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p-s sj cW VlA.eVv' \ C C.W a '/'p' 'O l g/" American Society of Heating and Ventilating Engineers Heating ventilating air conditioning guide. VOL 30 19 St 628.8 AMERICAN 21718 78700 Ventilating Enginee No.- 6310715. This Book Shall Not Be Taken From The Library SC-ASHVE-028 { Heating Ventilating Air Conditioning Guide 1952 V HEATING VENTILATING AIR CONDITIONING GUIDE 1952 An Instrument of Service Prepared for 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, i ` Vol. 30 $o0-per Copy A310715 Published Annually by American Society op Heating and Ventilating Engineers 62 Worth St. New York 13. N. Y. i Copyright 1952 BY THE American Society of Heating Ventilating Engineers AND BY IT Dedicated To the Advancement of The Profession ` and ' Its Allied Industries TEXT AND ILLUSTRATIONS ARE FULLY .PRO TECTED BY COPYRIGHT AND . NOTHING THAT APPEARS MAY BE REPRINTED EITHER WHOLLY OR IN PART WITHOUT SPECIAL PERMISSION. Printed and Bound by Waverly Press, Inc. BALTIMORE MARYLAND U. S. A. ` 1 ^ so PREFACE TO THE 30th EDITION <A The Heating Ventilating Air Conditioning Guide, 1952, shows an increase over previous editions in both usefulness and size. The Technical Data Section which comprises 1064 pages of technical and design information on 50 different subjects, represents an increase of 16 pages in space, in addition to an equal increase filling the equivalent of 16 pages derived from condensation of previous text. The chapter arrangement of the last two editions has been retained, the chapters being grouped under the familiar section titles: I Fundamentals, II Human Reactions, III Heating and Cooling Loads, IV Combustion and Consumption of Fuels, V Systems and Equipment, VI Special Systems, VII Instruments ana Codes. While the entire book has been reviewed carefully and important revisions have been made throughout, special attention is called to the improvements in the follow ing chapters: Chapter S--Heal Transfer. The tables of unit conductances for thermal convection and methods for computing radiant heat exchange for various conditions have been brought into agreement with latest research results. djbapter 9--Heat Transmission Coefficients of Building Materials. The section on water vapor and condensation in building construction has been rewritten and enlarged. Particular attention has been given to the discussion of visible and con i cealed condensation and to methods of preventing moisture damage in buildings. A j number of new materials are listed in the tables of conductivities and conductances, and revised values are shown for previously listed materials where new data have become available. Chapter 11--Heating Load. Average winter temperatures for October to May were obtained from the V. S. Weather Bureau and the Canadian Meteorological Service and are listed in the table of Winter Climatic Conditions for 316 United States cities and 16 Canadian cities. Chapter IS--Cooling Load. Design tables for heat gain through fiat glass and glass block have been simplified, and design tables for figured rolled glass have been added. Chapter IS--Fuels and Combustion. The sections dealing with oil and gas fuels have been rewritten and expanded to include more information on properties and combus tion data for present day fuels. T Chapter IS--Heating Boilers, Furnaces, and Space Heaters. Boiler rating informa tion has been brought up to date and a new abridged table showing current I-B-R boiler rating and sizing practice has been added. Chapter 16--Chimneys and Draft Calculations. The section on residential chimneys has been rewritten with special emphasis on the performance and selection of lowheight chimneys for basementless and other low buildings. The information is based on National Bureau of Standards test results. A new chart for determining gas appli ance vent and chimney sizes is included to show recommendations of the American Gas Association. Chapter 17--Estimating Fuel Consumption for Space Heating. The chapter was revised by the Technical Advisory Committee on Combustion. New constants were determined for use in fuel consumption formulas. All illustrative problems were reworked using the suggested constants. Chapter SO--Steam Heating Systems. Several piping diagrams have been improved by changes which bring them up to date with recent practice in the industry. Chapter SS--Radiators and Convectors. The information on baseboard type of radiation has been extended. Btu ratings have been added to the previous Equiva lent Direct Radiation ratings of the currently manufactured sizes of radiators. Chapter S4--Unit Heaters and Unit Ventilators. The unit ventilator section has been rewritten in conformity with present practice in rating and installation. Sev eral unit heater piping diagrams have been revised. Chapter SS--Unit Air Conditioners and Unit Air Coolers. Sections dealing with construction, ratings, operation and application of room coolers have been enlarged. Chapter SS--Fans. A section has been added on application of fans for high temper i a .uJ"e Work. Nomenclature and designations for fans have been brought into accord with latest industry practice. v j . Chapter S3--Air Cleaning. The surfiM^ sijbtidn has been rewritten to provide more . data on types of filters and dusts .encountered. Information has been added describing the charged-media type of filter. ' ' ...................... Chapter 36-^Refrigeration. The section on the absorption system has been enlarged to include a diagram and description of the lithium bromide-water absorption system Chapter 44--Industrial Air Conditioning. The table showing recommended air conditions for manufacturing, storing, and handling various types of products has been greatly enlarged,, and many important factors affecting the processes involved have been listed with the various products. '' Chapter 50--Ctides and Standards. The list of codes and standards has been enlarged to include new codes of interest, and latest editions of all codes have been indicated. Names and addresses of organizations which can supply the codes and standards are listed for convenience in obtaining copies. A comprehensive cross index is included for the Technical Data Section. , As a convenience in finding available types of equipment, this volume contains a Catalog Data Section listing the names, addresses and brief descriptions of products of 277 manufacturers. The section is provided with an elaborate cross index. : In the preparation of this edition, the Guide Committee has been able to draw upon the resources of information represented by: the experiences of many Society mem bers and other practicing engineers; the files of trade associations, government agencies, and various engineering publications; and the data collected and compiled by the Technical Advisory Committees and the Research Laboratory of the Society. It is impossible to give full credit to. all of those who have shared in bringing The Guide to its present position of usefulness to the heating ventilating air conditioning profession. To those who have contributed so much in the compiling of previous editions, The Guide Committee is pleased to add the names of those who have been most active in preparing this volume: 1. P. R. Achenbach C. B. Bbadley R. B. Cbepps " . R. B. Engdahl H. G. Gbagg N. A. Hall W. R. Heath R. C. Jobdan F. A. Joy M. W. Keyes W. B. Kibk A. A. Mabks G. W. McCobmick, Jb. A. J. Nesbitt G. V. Pabmelee H. E. Robinson F. E. Romie F. B. Rowley T. H. Smoot Benjamin Spieth C. S. Stock Geohge SVoboda L. V. Teesdale W. N. Withebidge The 1952 edition of The Guide is presented with confidence that it will serve to advance the arts and sciences of heating, ventilating, cooling, and air conditioning. GUIDE COMMITTEE P. B. Gobdon, Chairman D. B. Andebson W. S. Habbis W. E. Long F. J. Nunlist, Jb. N. Glickman- B. H. Jennings P. J. Mabschall C. D. Shields . Cybil Taskeb, Ex-Officio Cabl H. Flink, Technical Secretary ; VI ' Contents . - - r :. ; Page Title Page..................................................... ......................... ..............................................'. iii Pheface............. .................................................................. ....................................,......... v Index to Technical Data...................................... .............................................................. ix SECTION I. FUNDAMENTALS Chapter . 1.Terminology....................................................................... .:.................... 2. Abbreviations and Symbols.___ _..:.;. . . . .......... ....... . *... 3. Thermodynamics........... .................................................... ~23 4. Fluid Flow............................................... ............................ J..:.;............ 5. Heat Transfer................................................................... ,...................... 1 -11. 67 89 SECTION Ii: HUMAN REACTIONS ''' ' Chapter 6. Physiological Principles..............................;.................... 111 7. Air Conditioning in the Prevention and Treatment of Disease; 131 8: Air Contaminants.................................... :.................. 151 SECTION m. HEATING AND COOLING LOADS .Chapter 9. Heat Transmission Coefficients of Building Materials.............. 167 ' . 10. Infiltration and Ventilation.:.......................... ................................... 213 . 11. Heating Load.......................................................................... '............... 233 12. Cooling Load............................................................................................... 257 SECTION IV. COMBUSTION AND CONSUMPTION OF FUELS Chapter 13. Fuels and Combustion................................................ 14. Automatic Fuel Burning Equipment................................................. 353 15. Heating Boilers, Furnaces, Space Heaters...................................... 377 16. Chimneys and Draft Calculations.......... .................................. 17. Estimating Fuel Consumption for Space Heating..........................423 403 SECTION V. SYSTEMS AND EQUIPMENT . Chapter 18. Gravity Warm Air Systems................................................................... 439 19. Forced Warm Air Systems..................................................................... 449 20. Steam Heating Systems.......................................................................... 469 21. Hot Water Heating Systems.................................................... 511 22. Radiators and Convectors..................................................................... 529 23. Panel Heating............................................................. '................... _____ 541 24. Unit Heaters and Unit Ventilators.................. :.............................. 555 25. Unit Air Conditioners and Unit Air Coolers.................................. 571 26. Pipe, Fittings, Welding.......................................................................... 585 27. Pipe Insulation................................................................. 28. District Heating........................................................................................ 619 29. Central Systems for Air Conditioning...................................... 629 30. Air Distribution......................................................................................... 645 31. Air Duct Design............................................................ ,........................ 669 32. Fans............................................................................................................. 705: 33. Air Cleaning................................................................................... 723 34. Spray Apparatus............................................................. 35. Air Heating and Cooling Coils............................................................ 767 36. Refrigeration............................................................................................... 791 - 37. Dehumidification by Sorbent Materials.............................................829 38. Automatic Control...................................................... ; 39. Motors and Motor Controls................................................................. 855 40. Sound Control............................................................................................ 871 . 41. Electric Heating............................................................ :........................ 893 42. Corrosion and Water Formed Deposits, Causes and Prevention 901 43. Owning and Operating Costs............................................................... 923 vu 317 603 741 839 ' .. SECTION VI. CONTENTS. (ConcludedX/ . ' ` : .. SPECIAL SYSTEMS ; - Chapter 44. Industrial Air Conditioning.................................................------------- 933 45. Industrial Exhaust Systems............................................ :..........955 46. Industrial Drying Systems........................ ;..............................:------ 969 47. Transportation Air Conditioning... ................................................. 997 48. -Water Services.................. ........................ ....................................... ;. .1013 SECTION VII. INSTRUMENTS AND CODES ' Chapter 49. Instruments and Measurements.. ................................................... 1037 50. Codes and Standards...............................................................................1057 CATALOG DATA SECTION.......................................................................... Index to Advertisers....................................... ............................................................ 10^ Index to Modem Equipment........................................................................................... 1073 Manufacturers' Catalog Data...................................................................................... -1097' 1065 INDEX Heating Ventilating Air Conditioning GUIDE 1952 TECHNICAL DATA SECTION CHAPTERS 1-50 and PAGES 1-1064 ' Cross Reference to Subjects in Chapters 1-50 Alphabetically Listed 30th EDITION viii INDEX HEATING VENTILATING AIR CONDITIONING GUIDE 1952 Technical Data Section Chapters 1-50 and Pages 1-1064 A Abatement ' air pollution* 151, 154 v smoke* 8, 155, 322 Abbreviations* 11 Absolute humidity, 5 pressure, 7 temperature, 9, 30 zero, 1, 30 Absorbents, 834 process, 834 temperature, pressure, centration, 835 con Absorbers ^ duct, sound, 880 * outlet, 885 .. plate cells, 883 ' ' plenum, 885 Absorption systems, 807 Acceleration, 1 Acclimatisation 118 Acoustics, 871 Activated alumina, 830 Activated carbon, 147, 829* 1000 Activated bauxite, 831 Adiabatic, 1 miring - two air streams, 57 saturation, 60 Adsorbents. 829 . process, 831 temperature, pressure, con centration, 835 Adsorption, odor, vapor, 156, 829 Aerosol, I, 134, 151 Air change measurement, 1049 change method, 218, 249 chemical vitiation of. 111, 152, 156 ' circulation, 112, 439, 449, 629, . 669, 998 _ circulation in drying, 988 classification of impurities, , 151, 724. dust, 151, 724 . lout, 151, 724 Cleaner, 151, 723, 998 viscous impingement type, , 725 . cleaning, 723 clcsnmg devices, 709 classification of, 709 installation, 732 Air (continued) cleaning devices (continued) ' maintenance, 731 performance, 729 safety requirements, 733 ` selection, 731 testing, 729. vapor adsorption, 733 combustion, 343, 344 conditioning process, 629, 933 . contaminants, 111, 151, 955, 1054 cooled condensers, 816 cooling, tropics, 136 current measurement, 1048 dehumidification, 829 . . distribution, 439, 449, 645, 998, 1004,1007 air entrainment, 647 application of methods, 665, 998 balancing the system, 660 ceiling outlets, 658 - definitions, 646 duct approaches to outlets, 441, 661 flow patterns, 661 friction chart, 670, 671 furnace systems, 439, 449 guide vanes, 450, 653 induction, 647 . jet pattern, 648 mechanics, 647 momentum theory, 647 outlet location, 658 outlet performance* 655 - outlets, 657 parallel slots, 649 railway car, 998 recommended velocity, 450, 686 return and exhaust intakes, 664, 888 room air motion, 654, 656 ' spread, 647, 652 ' standards for, 645 .throw, 646,- 650 vanes, 450, 653 velocity, 557, 558, 669 velocity across jets, 648 vertical drop and rise* 654 volume control, 663 wall outlets, 450, 654, 657 duct construction, 694, 964 duct design, 451, 669, 964 duct friction loss, 669 dust concentrations, 155, 160, 161 excess, 326, 337, 344, 365, 371 filter, 723 flow resistance of coils, 777 impurities, 113, 151, 723 infiltration, 213 causes of, 213 . due to wind pressure, 213 through walls, 214 XI Air (continued) " infiltration (continued) leakage, 213, 217, 326 . moist, 25 * motion, 122 . ' " movement, influence of, 117 movement, -measurement of, 1043, 1047 ; . outdoor, 112, 629 . physical impurities' in* 113, 151,155, 723 . pollution, 151,155 abatement, 155,322,955 primary, 324 quantity required, 112, 343, 344, 999,1001 refrigeration cycle, 804 room motion, 640, 642 saturated, 1 secondary, 324, 341, 371 space conductance, 170, 180 standard, l . sterilization of, 132, 142 . supply and return openings, 440, 450,655, 657 supply opening noise, 657, 885 temperature requirements, 123, 126, 241, 258, 934-944, 1007 theoretical requirements, 112, 342, 344, 1008 thermodynamics of, 23 unit cleaning devices, 723, 732, 741 washers, 1, 741 Air change method computing infiltration, 218, 249 . Air conditioning* 1 aircraft, 1003 automobiles in summer, 1003 central system, 629 . ' comfort, 2 . . hospitals, 131-148 humidity, table, 934 industrial, 933 ' atmospheric conditions re quired, 259,-934-944 calculations, 949' general requirements,'933 problem classification, 933 typical applications, 933 owning ana operating cost, 923 passenger bus in summer, 1002 processes, 54 adiabatic mixing, 57 adiabatic saturation, 60 cooling, 55 heating, 54 . railway passenger car, 997 ship, 1006 stoker-fired units, 354 storage systems, 809 streetcar, 1001 Heating Ventilating Air Conditioning Guide 1952 . Air conditioning (continued) summer dA<ngn. conditions, 258, 259. 261 temperature table, 258, 259, 261, 934 transportation, 997 treatment of disease, 131 unit.. 571 ' Air cooler, 571 units, 571, 581 defrosting, 582 design, 581 operation, 583 performance, 582 ratings, 582 types of, 581 Air biters, 723 Air pollution, 154 control, 155, 322, 956 Air requirements, 112, 999 Air supply opening noises, 657, 885 . Air velocity, 450, 557, 647, 663 677, 686, 957, 963 cooling towers, 756 design, 686 residual, 650 unit heaters, 557 Air washer, 1, 741 Airborne infection, 132, 164 control, 132, 164 Airfoil fan, 705 ... Aircraft air conditioning, 1003 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, 1046 deflecting vane, 1047 propeller, 1046 revolving vane, 1046 thermal, 1048 Anesthetics, 138 Anthracite coal, 318, 321, 353 firing methods, 321 Apparatus dew-point, 258, 633, Aspect ratio, 1, 646, 648 Asthma symptoms,,145 Atmosphere, standard, 63 Atmospheric _ _ conditions for industrial proc esses, 934-944 cooling towers, 751 make-up water, 765 winter freezing, 766 Atomizing humidifiers, 745 Atomizing oil burner, 361 Attenuation, 879 ducts, 879 duct branches, 879 elbows, 879 grilles, 879 Attic fans, 721 location, 721 types, 721 temperature, 243 - Automatic controls (see Controls), 458, 839 application, 846 purpose of, 839 types of, 839 Automatic (continued) fuel burning equipment, 353 viscous filter, 726 Automobile air conditioning, 1003 Axial flow fans, 705 ' B Boiler, boilers (continued) steel, 378 stoker-fired units, 354 testing codes, 382 troubles, 389 * types, 377 British thertoal units, 2Bucket trap, 500, 502 Baffle, 1, 368 Bare pipe heat loss, 603 Barometer, 1042 Basement coefficients of transmission, , 185 heat loss, 185, 245 temperatures, 245 Basementless houses, 246, 465 Bernoulli equation, 68 Biochemical reactions control of rate of, 947 Bituminous coal, 317, 322. firing methods, 322 Blast heater, 2 Blow, 2. 558, 646 Body adaptation to hot conditions, 118 heat loss, 113, 120 odor. 111 thermal interchanges, 119, 120 Boiler, boilers, 377 capacity for unit beaters, 564 care, 390 cast-iron, 377 cleaning steam, 390 combustion rates,*386 connections, 388, 496 ' Hartford return, 496 return, 496 sizing, 487 steam, 486 construction, 377 design, 379 efficiency, 382 electric, 896 erection, 389 fittings, 388 furnace design, 379 gas-fired, 368, 388 selection of, 383, 388 gas-fired units, 368 \ conversions, 368 selection of, 368, 383, 388 heating, 377 heating surface, 2, 379 heat transfer rates, 379 horsepower, 2 hot water supply, 385, 1027 load. 385 . maintenance, 389 * oil-fired units, 365 operation, 389 output, 382 rating, 380, 383 rating codes, 380, 1057 selection of, 385 based on heating surface and grate area, 387 cast-iron, 386 . estimated design load, 385 estimated maximum load, 385 gas-fired, 388 hot water supply load, 385, 1024 piping tax, 382, 385, 603 radiation load, 385 steel, 380, 385 warming up allowance, 385, 388 . soot, 350 . space limitations, 388 special heating, 378 XU Building, buildings condensation, 198-211 heat transfer through surfaces 186-197 infiltration, 213, 248, 300 intermittently heated, 251 materials, heat transfer , through, 170, 177, 183, 186, 246 multi-story, air leakage, 219 Burner, oil, 361 Bus air conditioning, 1002 By-pass, 2, 622, 630 c Calcium chloride, 829, 834 Calculated heat loss method, 233 Calorie, 2 Calorific value, 318, 329, 334, 335 Carbon activated, 148, 829,1000 dioxide, 111, 158,324, 332, 339 350 monoxide, 158, 339-350 Cast-iron boilers, 377 ' Ceiling cooling units, 582 high, 241 . ,. outlets, 658, 999 perforated, 658, 999 unit heater, 557 Central air conditioning sys tems, 629 , accessibility, 643 air quantity, 635 apparatus dew-point, 633 control, 630 cooling load, 257, 634 . corrosion, 916 design procedure, 643 effectual temperature differ- ence, 635 equipment arrangement, 629 633 equipment selection, 640 evaporative cooling, 639 fan system, 2 features. 629 - heating load, 233, 635 individual room control, 632, induction units, 637 high pressure type, 638 low pressure type, 637 location of apparatus, 642 outdoor air, 629, 634 pre-cooling, 639 reheating, 630 - run-around, 640 -- selection, 640 . sensible cooling, 639 storage capacity, 635 zoning, 630 . Centrifugal compressors, 815 condensing unit, 815 fan, 705 Charcoal, 156, 733 Index to Technical Data Section Chart air elimination, 481 air flow unequal openings, 222 air flow and sound level, 887 air friction, 670, 671 chimney capacity,- 408, 410, 411, 413, 416, 417 . chimney draft, 407, 408, 410, 411, 412 chimney flow, 410, 411, 413,414 coil temperature, 552 color, 22 comfort, 126 ,. compressor and coil perform ance, 827 correction for pipe roughness, 673 dehumidifier performance, 838 design temperature map, 240 disease frequency, 133,134 draft required, 404 dry vs. wet weight, 971 drying time, 972, 973 drying weight, 972 dust particle size, 153 economical thickness pipe insulation, 616 edge loss, 247 effective diameter, 652 effective temperature, 124, 125, 126, 127 elbow loss, 678, 679 entrainment ratio, 649, 651 . estimating surface tempera ture, 198, 549 expansion factor, 81, 82 evaporation chart, 985 fan characteristics, 710-712 fan sound level, 710, 711, 712, 877-879 fan system characteristics, 713 filter resistance. 730 firebox dimensions, 360 flow due to wind, 223 flow through opening, 222 flow coefficients, 79, 80 flue area, 229, 416, 417 flue loss, 339, 340 friction air ducts, 670, 671 friction factor, 71 friction in pipes, 513,515,1016 1018 fuel consumption, 374, 375 fuel oil index, 332 gas vents, 416 head due to temperature, 512 heat flow, glass, 289 heat emission by radiation from panels, 545 heat endurance, 119 heat loss body, 115, 116, 120, 121, 122 canvas surface, 610 coefficients, insulated ducts, 700 . convection from panel, 547 duct, 700 floor, 247 * insulated pipe, 607-610, 612 insulation, 607, 608, 609, 616 humidity, 982 infiltration, 215 inside surface temperature, . 549, 550 insulation of cold pipe, 612 hangelier formula, 910 moisture loss from body, 122 motor characteristics, 860-863 MRT elevation, 119 orifice coefficient, 77 orifice installation, 83 Panel heat output. 545, 547,548 permissible relative humidi ties for various transmis sion coefficients, 200 pressure loss in ducts, 670, 671 pressure loss in elbows, 678. 679, 681 pressure loss in faucets, 1019 Chart (continued) ' pressure loss in meters, 1019 psychrometric charts, 51, 983 persons at rest, 124 pump performance, 522 radiation between black ' bodies, 99 ' radiation shape factor, 98 refrigerant pressure-enthalpy 794 refrigeration horsepower, 931 residual velocity, 651 . room absorption correction. 889 solubility of calcium salts, 907,908 . solubility of gases, 906 sound attenuation, 883 static deflection, 891 static regain, 691, 692 system characteristics, 713 temperature in panel, 552 thickness pipe insulation pre vent sweating, 612 velocity and velocity head, 677 vena contracts location 85 viscosity, air, 69 viscosity, water, 70 well water temperatures, 746 Chemical ' laboratory hoods, 962 reactions, 945 control of rate of, 645 vitiation of air. 111, 156 Chimney, chimneys, 403 available draft, 405, 410 construction details, 418 determining sizes, 408, 412 effect, 2 factors affecting draft, 404 gas heating, 417 general considerations for, 403, 418 industrial; 405 performance, 408-414 residential, 409 sues, 408, 412 static draft, 404 theoretical draft, 403 Cinders, 151 Circular equivalents of rec tangular ducts, 673 Circulators, 622 Cleaning boilers, 390 Climatic conditions, 235, 261 Closed expansion tank, 524 sizing formula, 525 Coal, coals anthracite, 317 bituminous, 317 classification of, 318 dustless treatment, 320 estimating consumption, 423 firing methods, 321 lignite, 319 Codes, 1057 installation, 1057 rating, 1057 testing, 1057 Coefficients of transmission, 5, 100, 181-197, 603, 781 basement, 245 floor, 192, 245-247 wall, 245 coils, 532, 604, 781 doors, 197 floors and ceilings, 191, 192 frame construction, 186, 190 glass, 197 glass block walls, 197 Coefficients of transmission (continued) masonry partitions, 190 . . masonry walls, 188 overall, 181 formulas for calculating, 181 roofs, 193-196 skylights, 197 windows, 197 Coil, colls, 767 air flow resistance, 779 applications, 773 arrangement, 768 construction, 768 cooling, 767 dehumidifying, 777 direct-expansion, 770 dry cooling, 573, 639, 781 film coefficient, 784. 785 flow arrangement, 772 heat emission, 532, 781, 1030 heat transfer surface, 779. heating, 776 performance, 781, 783 cooling, 781 dehumidification, 783 heating, 781 . rating, 777 ` selection, 775, 786 cooling, 777, 788 dehumidifying, 777 beating, 776 steam, 769 uses, 767 water, 770 Coke classification of, 320 estimating consumption, 423 firing methods, 323 Cold therapy, 143 Color, piping systems, 22 Combustion, 317 ' adjustments, 354, 366 air required, 343 analysis, 344 chamber, 360, 367 dew-point, 350 flue gas, 344, 346 gas, 336 heat balance, 347 heat of, 341 index, 331 losses, 348 oil, 330 principles of, 337 rates, 374, 404 smokeless, 322 Comfort air conditioning, 2 air conditioning systems, 629. 997 chart, 126 line, 2 zone, 2 Compartment dryer, 991 Compressor, compressors 813, 815 centrifugal, 813 reciprocating, 813 refrigeration, performance of, 824, 825 rotary, 813 . Condensates, 904 Condensate return pumps, 498 Condensation 'buildings, 198 concealed, 204, 207 control, 207 interstitial, 204 surface, 199 Treating Ventilating Air Conditioning Guide 1952 Condensers, 816 air cooled, 816 design data, 758 evaporative, 816 water cooled, 816 Condition line, 59, 309, 633 Conductance, 3,167, 170,' 180 air space, 170,178 building materials, 171, 180 insulators, 174,180, 606 soil, 169 surface, 177, 684, 765 Conduction, 3, 89 drying methods, 989 electric heaters, 893 equation, 90 steady-state solutions, 101 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, 606 ' insulation blankets, 174, 180 insulators, 174, 180, 606 loose-fiU insulation, 175, 180, 187 masonry materials, 171, 180 plastering materials, 173, 180 reflective insulation, 170, 180 rigid insulation, 175, 180 roofing construction, 173, 181 soil, 176, 177 woods, 173, 181 - Conductor, 3 Conduits for piping, 621 Control, controls actuated, 841 actuating, 840 airborne infection, 132 all-year conditioning, 630, 844, 848 application, 846 automatic, 458, 839 fuel appliances, 361, 843 ' temperature, 844 basic types, 839 central fan system, 629, 848 ' all-year system, 629, 848 heating cycle, 635 coal-fired plant, 842 compressor, 847 cooling units, 848 dehumidification, 848 . dehydrating equipment, 833 designation, 839 district heating, 851 draft, 326 electric heating, 843 electronic, 839, 853 * equipment for motors, 866 fan, 716 gas burner, 843 gas-fired appliances, 843 heating unit, 842 hot water supply, 1031 humidity, railway care, 1000 ice bunker, 847 indicating, 854 individual rooms, 1010 limit, 843 - modulating, 844 motor, 820 oil burners, 842 panel heating, 852 pneumatic systems, 839 _ rate of biochemical reactions, 947 . rate of chemical reactions, 945 rate of crystallization, 947 recording, 854 i- Control, controls (continued) refrigeration equipment, 813, 847 ' ' compressor type, 847 ice cooling, 847. well water, 847 regain, 944 '- residential systems, 842 room thermostat, 843 - service water temperature, 1031 ship control, 1010 single .phase motor, 867 Bound, 871 squirrel-cage motor, 866 steam jet system, 848 stoker. 361. 842 system, 644 temperature, 844 terminology, 839 two-position control, 839 unit cooler, 847 ' unit heaters, 846 unit systems, 846 - unit ventilators, 846 valves, 509, 599, 841 ventilator, 226 volume, 661 well water, 847 zone, 844 Controllers, 839 functions, 839 types, 839 Convection, 3, 89, 99 equation, 91 unit conductances, 94 Convector, convectors. 3, 529, 533 correction factor, 534, 536 heat emission, 535 heating effect, 535 induction, 637 - ratings, 534 Converging vanes, 653 Conversion burners, 361, 368 . equations, 15, 203 Coolers, 571, 581 Cooling, 257, 571 air conditioning units, 571 atmospheric water, 741 coil selection, 777 evaporative, 639 load, 257, 634 methods. 466 ' performance of coils, 781, 783 ponds, 749 residential, 466 sensible, 639 spray, 745, 749 effect of wind, 750 make-up water, 765 size of equipment, 751, 755 winter freezing, 766 systems. 467, 629,999. 1002 tower design, 757, 758 tower performance, 760 units, 571 component parts, 572 control. 578 definitions, 571 defrosting, 582 design, 572 performance, 571, 579,583 ratings, 578, 582, 583 remote, 576 sound isolation, 575 types of, 571 water, 756 water piping, 1022 ' Copper elbow equivalents, 513 Core area, 646, 1047 Corrosion, 585, 901 air ducts, 917 atmospheric, 916 boilers. 908 cathodic protection, 919 coal storage equipment, 917 cold water, 912 condensates, 904, 914 flues, 917 heating systems, 908 ' hot water, 913 . industrial exhaust systems, 967 minimizihg condensate, 914 pipe, 918 prevention, 918, 967 refrigerating-systems, 913 ' underwater, 911 Cost of air conditioning, 923 amortization, 923 ' condenser water, 929 first, 923 fixed charges, 923 heating, 931 interest, 926 installed, 923 insurance, 927 maintenance, 927 owning and operating, 923 rent, 927 - service, 928 taxes, 927 Crack length used for computations, 249 Crystallization control rate of, 947 Cylinder dryer, 990 D Dalton's rule, 28 Damper, dampers, 326, 451, 629, 662, 849 Darcy formula, 69 Decibel, 871 Definitions, 1 Defrosting, 582 Degree-day, 3, 417 for cities, 429 - formula for, method, 428 operating unit, 438 ( unit fuel consumption, 434, 435 Degree of saturation, 8, 25, 31 Dehumidification, 633, 745, 829 air conditioning units, 576 air washers, 745 coil selection, 767, 777 comparison of methods, 829 control, 833 definitions and methods, 829 equipment, 633, 829, 633 performance, 832 estimating loads, 836 liquid methods, 834 ships, 1009 solid methods, 833 Dehumidifying agents, 829 sorbents, 829 absorbents, 829 adsorbents, 829 Density of air, 1 Design conditions summer, 258, 261 winter, 235, 241 . Dew-point apparatus temperature, 309, 633. 644 .. flue gas, 350, 917 temperature; 9, 26, 1050 Dichlorodifiuoromethane, 793, 794 XIV 1 I - ; Index to Technical Data Section Direct expansion coils, 770 fired unit heater, 555 indirect beating unit, 3 radiator, 7 return system, 3, 518 Disc fan, 705 - . Distribution of air (see Air Distribution), 439, 449, 829. 645, 671, 998, 1004 District heating, 619 automatic control, 851 glossary of rate terms, 627 meters, 625 . piping, 619 ' conduits for,. 621 inside, 623 overhead distribution, 623 sizes, 620 tunnels, 623 rates, 627 * steam requirement, 627 Diverging vanes, 450, 653 Domestic oil burners, 361 Door, doors coefficients of fransmission, 203 leakage, 215, 217 natural ventilation, 215, 225 Down-Feed one-pipe riser, 3, 6, 471 steam heating, 3, 477 system, 4, 469 Draft, drafts, 4, 403 available, 405, 410 - calculations, 403 chimney, 403 - control, 326 * factors, 404 ' Sneral equation, 403 . ad, 4 industrial chimneys, 405 mechanical, 403 natural, 213, 403 regulation, 326 residential chimneys, 409 requirements, 325, 404, 415 theoretical, 403 Drawing symbols, 17 Drip, drips, 4,. 471, 505 Drum dryer, 990 Dry air, 1 composition, 25, 341 . density, 32 ` filters, 723 properties of,.30 velocity head, 677 Dry-bulb temperature, 9 Dry cooling coils, 639, 767, 781 Dry return, 8, 469 Dryer, dryers, 988 cabinet, 990 . calculations, 984 compartment, 990 cylinder, 990 drum, 989 rotary, 990 spray, 990 tunnel, 990 Drying, 945, 969 application of hygrometry, 983 calculations, 984 chart, 983, 985 conduction, 989 constant rate period, 973, 975 convection, 989 control, 987 critical moisture, 980 effect of air velocity, 974 Drying (continued) equations, 980 . equilibrium moisture, 981 " equipment, 988 \ example, 992 external conditions, 971 factors influencing, 970 falling rate period, 917 internal conditions, 971 mechanism of, 970 methods, 988 conduction, 989 convection, 989 radiant, 988 periods, 972 problem, 992 radiant, 988 . surface temperature, 974 systems, 969 terminology, 969 - Duct, ducts, 441-443, 452, 669 air velocities in, 450, 685, 963 approaches to outlets, 661 area change, 680 attenuation, 879 circular equivalents, 673 construction details, 694 design, 442, 452, 685, 696, 964 design methods, 687 elbow friction losses, 678, 966 exhaust Hpaign, 9Q4 friction losses, 669 heat loss coefficients, 697 lining, 882 maintenance, 701 measurement of velocities, . 1043 noise transmitted, 874 pressure changes, 683 pressure loss, 669, 678 - . recirculating, 441, 443, 450, 664 rectangular equivalents of round, 417, 673 resistance, 669, 966 roughness correction, 673 aide outlets, 662 sizes, 669 sound absorbers, 880 ' symbols for drawing, 19 . system design, 442, 452, 669 Duct sizing, 669, 685 equal friction method, 688 general rules, 442, 452, 687 static regain method, 690 velocity method, 687 Dust, 4, 151 combustible, 161 concentrations, 155 determination, 154 filtera, 723, 727 precipitators, 727 removal, 723 size, 153 Dust collectors, 723, 735 application, 719 centrifugal, 737 cinder catching, 722 cyclone, 737 dry dynamic, 721 high efficiency, 721 electrostatic, 735 fabric, 736 factors affecting selection, 734 settling chambers, 738 testing methods, 738 wet, 736 centrifugal, 737 disintegrator, 737 dynamic precipitator, 737 orifice type, 737 packed tower, 737 washers, 720 XV Dynamic-head, 5, 674 tames,' 674 . EDR (Equivalent direct radia tion) 7,385, 480, 484, 486, 488. 529 ' defined, 7, 385, 529, 534 Effective temperature, 9,122 chart, 125, 126 index, 122 Ejector nozzles, 658 Elbow attenuation, 879 copper equivalents, 513 friction losses, 485,513 iron equivalents, 485, 513,1020 sheet metal, equivalent, 443. 456, 678, 679 681, 966 Electric, electrical air conditioning, 895 boilers, 895, 896 control systems, 839 . heaters, 893 conduction. 893 gravity convection, 894 radiant, 894 heating, 893 calculating capacities, 898 central fan. 895 control, 839 domestic water, 896 elements, 893 induction, 898 - power problems, 899 resistors, 8, -693 . hot water heating, 897 motor design limits, 856 panel heating, 544 precipitators, 727 radiant heating, 894 resistors, 893 systems, 855 voltage ratings, 856 unit heaters, 894 Electricity static, 948 Emissivity, 95, 170 Enclosed radiator, 539 Enthalpy, 4, 23,30,51 free, 4 specific, 4, 30 Entropy, 4, 30, 51 mixing, 51 Equivalent evaporation, 4 Estimating fuel consumption, 423 Eupatheoscope, 1052 Evaporative condensers, 816 cooled, unit conditioners, 571 cooling, 639 Evaporators, 817 Excess air, 341, 344,347, 371 Exhaust opening, 664, 956 measurement of velocities. 960. 1047 Exhaust systems, 955 air flow measurement, 959 axial velocity formula, 959 capture velocities, 957 classification of, 955 conveying velocity, 963 corrosion, 967 duct construction, 964 duct design, 964 Heating Ventilating Air Conditioning Guide 1952 . Exhaust systems {continued) duct resistance, 066 duct velocity, 957, 963 ducts for, 964 air velocities in, 657, 963 construction, 965 design, 960 resistance, 966 dust filters, 723 -- efficiency of, 966 hoods, 956 air Sow, 959 . air velocity, 959 axial velocity formula for, 959 canopy, 962 capture velocities, 957 chemical laboratories, 962 design principles, 961 kitchen, 963 large open, 961 lateral exhaust, 962 low velocity systems, 960 spray booths, 962 suction, 957 velocity contours, 960 resistance of, 966 ' suction requirements, 959 types of fans, 705 velocity contours, 960 velocity requirements, 964 Expansion ' factor, gases, 81, 82 of pipe, 508, 590 tank piping, 524 tank size, 524 tanks, 524 valves, 819 F Fan, fans, 449, 705 application, 719 arrangement of drives, 714 . attic, 721 location, 721 - ftTiftl flow, 705 centrifugal, 709 characteristic curves, 71(1*712 control, 716 designations, 706, 715 efficiency, 709 . exhaust, 720 furnace system, 449 installation, 719 lawa, 707 marine, 720 mine, 720 motive power, 717 noise generated, 710, 876 . performance, 705, 709 radial flow, 705 selection of, 717 air conditioning systems, 717 industrial exhaust systems, ' 967 speed, 718 .. system characteristics, 713 unitary systems, 720 volume control, 716 Fanning formula, 69 Fever therapy, 142 equipment for production of, 143 Film conductance, 92, 167, 168, 179, 783 Filter, filters, 723 _ air conditioning units, 570, 675 ' dry air, 723, 727, 998 dust, 723 . installation, 732 performance, 729 . Filter, filters {continued selection, 731 testing, 729 4 viscous automatic, 726 viscous impingement 725 . ' type, Fittings sheet metal, 443, 446, 456,.678, 681, 966 pipe. 485, 513, 575, 585, 1020, 1021 allowance, 443, 456, 485, 513, 966, 1020 Flexible mountings, 889 Float trap, 500 Floor cooling unit, 571 heat transfer coefficients, 191, 192 unit heater, 555 Flow . coefficients, orifices, 77 compressible fluids, 73 critical, 76 measurement head meters, 78, 83 - liquids, 78 orifices, 78 Pitot tube, 84, 1043 variable area meters, 86 Flow meters, 78, 625, 1020 Flue gas loss, 347 Fluids flow, 67 theory, 67 Fluid meters, 78, 625 Fog, 4, 152 . Force, 4 Forced . air heating system,f449 circulation pipe sizee,|518 convection, 92, 93, 781 Free convection, 92, 94 enthalpy, 4 Friction loss air ducts, 464, 669 circular pipes, 69 elbows. 443, 456, 485, 513, 966, 1020 gas piping, 372 non-circular pipes, 72 refrigerant piping, 822, 823 water heating, 513-515 water piping, 513-515, 1016 1018 Fuel, fuels, 317 analysis, 317, 327, 334 burning equipment, 353 classification, 317, 320, 328,335 consumption, 423 ~ degree-day method, 427 load factor, 438 maximum demands, 438 seasonal efficiency, 424 firing methods, 321 gas, 333 liquid, 326 solid, 317 4 unit consumption, 434 lltlllVfltlATI 30^ Fuel oil, 326 analysis, 327 carbon residue, 328 classification of, 326 combustion of, 330 flashpoint, 329 grade of, 329 XVI Fuel oil {continued) maximum carbon dioxide val ues, 345 ' theoretical air requirements,- 343 viscosity, 328 Fumes, 4, 151 Furnace, furnaces, 4, 391 . capacity, 393 ' casings, 397 cast iron, 393 % design, 396 efficiency, 396 fan; 392 forced warm air, 392 gas-fired units. 396 ' grate area, 395 a gravity warm air. 391 heating surface, 394 heavy duty, 392 _ humidification equipment, 397 materials, 398 , mechanical warm air, 392 controls, 458 cooling methods, 466 cooling system, 467 dampers'. 451 ducts, 451 fans, 392 -filters, 392 _ . method of designing. 396 motors, 392 ratings, 393 . oil-fired units, 392 rating, 393 steel, 393 - stoker-fired units, 354 G Gage, gages draft, 1042 pressure, 7, 1041 Garage ventilation, 231 Gas, gases, 152, 158 atmospheric, 152, 164, 905 burner controls, 843 chimneys for heating, 416 . classification of, 335 combustion of, 336 _ estimating coinsumption, 433 expansion factor, 61, 82 heaters, 401 pipe size, 372 solubility, 908 apace heaters, 401 specific heat, 5 Gaseous fuels ' classification of, 335 combustion of, 336 _ _ maximum carbon dioxide val ues, 345 ' products of combustion, 340, 342 properties of, 334 . specific gravity, 334 theoretical air requirements, . 342, 344 typical analyses, 334 Gas-fired appliances, 368 boilers, 368 combustion process, 371 . controls, 373 conversion burners, 368 furnaces, 368 _ measurement of efficiency of combustion, 371 ratings for, 372 _ . sizing heating plants, 382, 383 space heaters, 369 Index to Technical-Data Section Glass coefficient of transmission, 196 heat absorbent, 291 shading of, 297 solar heat transmitted, 286 292 window transmittance, 288 - Glass block walls coefficient of transmission, 197 solar heat gain, 292-298 Globe thermomenter, 1036 Graphical symbols for drawings, 17 ' air conditioning, 21 duct work, 19 " heating, 17 piping, 17 refrigerating, 21 ' ventilating, 19 Grate area, 5, 387, 394 Greek alphabet, 14 Grille, grilles, (see Register$), 439, 441, 450, 646, 657 air supply noises, 885 attenuation, 879 exhaust, 441, 664, 888 locations, 441, 658, 664 door, 665 floor, 665 wall, 665 - mechanical furnace systems, 450 noises, 664 - railway car, 999 recirculating, 999 return, 439, 441, 664, 888 selection, 886 velocity, 450, 663, 888 Ground temperatures, 244 Guarded hot plate, 1051 Gun type oil bumerB, 361 H Hangers plpe^`591 Hartford return connection, 471, 496 Hay fever symptoms, 144 Health, 131, 949 Heat, 5 area transmitting surface, 1029 auxiliary sources, 251, 302 balance, 347 combustion, 318, 335, 341, 342 emission of appliances, 304 occupants, 120-122, 303 - exchange measurements, 114 . now resistance, 99,167 flow through glass, 286 flow through roofs, 181, 193 196, 280-284 flow through walls, 282 gain, 257 ' ' generated by motore, 303 humid, 5 infiltration equivalent, 300 instantaneous load, 266, 299 introduced by outside air, 300 latent, 5, 249, 257, 302, 303, 304, 308, 312, 313, 314, 630, 633, 644 liquid, 5 - mechanical equivalent of, 6,15 Heat (continued) ' methods of, transfer, 89 radiant, 92, 95, 96, 529 Tremoval, natural ventilation, 222 sensible, 5, 248, 257, 266, 302, 303, 304, 308, 312, 313, 314, 633, 644 factor, 632 specific, 5 transfer, 89. 186-197, 529, 603, 697, 781 boiler rates, 379 overall coefficients, 99, 167, 168, 186-197, 529. 781, 1029, 1030 surface coils, 776 symbols, 12, 100, 167 through building Trmfpriftlf> 167 water coils, 1030 Heat gain, 257 appliances, 304 ceilings, 275 components of, 257 ducts, 635 electrical heating equipment, floors, 290 gas burning equipment, 306 glaret, 286 glass blocks, 290 infiltration, 300 instantaneous, 299 latent, 266, 644 lights. 303 moisture, 307 occupants, 303 outside air, 302 partitions, 299 people, 120, 302, 303 roof, 275, 278 sensible, 266, 630 shaded windows, 297' solar, 257 8team heated equipment, 305 various sources, 251, 308 ventilation, 300 - wall, 275, 278 Heat loss air change, 248 bare pipe, 532, 604 basement, 245 duct, 697 infiltration, 248 insulated pipe, 605 latent, 249 residence problems, 255 ' sensible, 248, 644 through ceilings and roofs, 248 to sky, 187, 273 transmission, 167, 24S Heat pump, 792, 810, 1035 Heater, heaters direct-fired unit, 555 electric, 557, 893 solar water, 1033 unit, 555, 894 vertical blow unit, 556 Heating air conditioning units, 571 boilers, 377 surface, 2, 399 coil selection, 775 district, 619 ' domestic water by electricity, 897 effect, radiator, 536 electric, 893 hot water, 897 load, 233, 384, 635 performance of coils, 783, 1030 xvii Heating {continued) reversed cycle refrigeration. 812 steam systems, 469 surface, 9 square foot of, 8 symbols for drawing, 17 up the radiator, 538 vacuum systems, 9,476 vapor, 10, 474 warm air system, 10, 439. 449 - water, 511, 1013 Heavy duty fan furnace, 392) High duty humidifiers, 7471A High temperature hazards,lll7, 137 Hood, hoods, 956 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, 385, 1023 coil surface, 1029 . demand per fixture, 1014, 1015,1026 person, 1023, 1024 electric heating, 897 heat pump, 1036 beating surface, 1029 indirect heater, 1027 methods of heating, 1026 panel heating, 541 safety devices, 1032 service, 1013 service piping. 1030 solar heaters, 1033 storage tank, 1023 supply - ' boilers, 378, 897, 1026 piping, 1013 temperature control, 1031 Hot water heating systems, 5,511 ' circulation head, 511, 512, 519 classification, 515, 518' direct return system, 516 elbow equivalents, 513 expansion tank, 524 forced circulation. 512, 515 friction heads, 512 gravity, 515 available head, 511 circulation, 511 _ pressure heads, 511 installation details, 527 mechanical circulators, 621 one-pipe forced circulation, 516, 519 gravity circulation, 516, 519 orifice friction heads, 517 pipe sizes, 513 forced circulation, 511 gravity circulation, 511 piping design, 518 pressure head, 512 reversed return system, 518 systems of piping, 518 two-pipe faired, 516, 519 gravity, 516, 519 zoning, 52$ Human body acclimatization, 118 Heating Ventilating Air Conditioning Guide 1952 Human body (continued) adaptation, 114 cold conditions, 115 hot conditions, 115 heat emission, 120, 303 high temperature hazards, 117 metabolic-rates, 116, odors, 111 . temperature, 114 thermal interchanges, 113, zone of evaporativeregulation, 115 Humid heat, 5 Humidification, 575, 743, 748 control, 463, 840 direct, 745 forced furnace systems, 397 Humidifier, humidifiers air washer, 743 atomizing, 747 . high duty, 747 spray, 748 unit, 748 . Humidity, 5 Humidistat, 5 Humidity, 5 absolute, 5 control, 840,1000 influence of, 122, 141 measurement of, 1049 . nurseries for premature in fants, 140 ratio, 5, 25 __ relative, 5. 25, 633 Hygrostat, 5, 840 ' I Ice systems, 809 Impulse trap, 500 Incn of 'water, 5 Induction units, 637 high pressure types, 638 low pressure types, 637 Industrial .. air conditioning, 933. conditioning and drying, 945 contaminant control, 950 control of chemical reac tions, 945 dilution systems, 950 Sjneral requirements, 933 umidities, 924, 948 laboratories, 948 machining tolerance. 948 moisture content and regain, 944 polished surfaces. 948 process, 933 safety, 949 static electricity, 948 . temperatures, 924 exhaust systems, 955 Infiltration causes, 213 . due to wind pressure, 213 heat losses, 248 latent, 249 . sensible, 248 temperature differences, 218 through outside doors, 217, through walls, 214 through windows, i*> Inflammability, 162 * Inside temperature, 4, zoo Instruments, 1037 Insulation, 6, 603 ' economical pipe thickness, 615 gravity furnace duct, 439 low temperature pipe, 612 pipe, 605 pipes to prevent freesing, 613 sound, 880 underground pipe, 617 Intermittently heated build ings, 251 Isobane, 6 Isothermal, 6 j Joints, duct, 694 K Kata thermometer, 537, 1048 Moist air. 25 properties of, 32 saturation, 29 specific volume, 32 Moisture, 198. 944 content, 944, 946 loss per person, 122, 303 permeability, 200 regain. 944 * . Mol. 6 Monofluorotrichloromethana, 793, 797 Motor, motors, 251, 392, 855 alternating current, 859 capacitor type, 862 classification, 858 control, 866 control equipment for, 866, 868 design limits, 856 . . electric, 855 enclosures, 869. L Laboratones, 948 Latent heat, 5, 248, 633 Ices, 249 . Laws of thermodynamics, 9 Leaders, 439 Leakage of air, 213 door, 215. 217, 225, 301 window, 215,216,225, 300 Light beat gain, 303 Lignite, 318, 319 - Lint, 724 Liquid absorbents, 834 heat of, 5 T.ithinm bromide, 808 Lithium chloride, 829 Load cooling, 257, 634 design, 6, 257 heating, 233, 635 maximum, 6, 385 refrigeration, 257 M Machine vibration, 889 Manometer, 6, 1041 Marine (see ship heating, venti~ laiing, air conditioning) Mass, 6 Hbh, 514 Mean radiant temperature, 119, . 548,551,854 Meter, meters, 78, 625 area, 78, 85, 625 condensate, 625 differential, 625 flow, 78,625 force, 78 head, 78, 83. 625 Nicholla' heat, 1052 orifice, 80, 626 selection, 627 velocity, 626 venturi, 1045 Metering, liquids, 78, 625 Micromanometers, 1042 Micron, 6 .Mist, 152 XV111 UCILUCUWuij -- multi-speed, 859 polyphase, 859 rating, 867 repulsion induction, 863 selection, 855 single phase, 862 ._ speed characteristics, 860, 863 speed ranges, 856 . split phase, 863 squirrel cage, 859 synchronous, 859, 866 wound rotor, 859, 866 N Natural draft, 403 towers. 735 . Natural ventilation, 220 gaeral rules, 228 at removal, 228, 230 Noise, noises, 871 absorptive material, 880-885 air conditioning system, 872 air supply opening, SS5 apparatus for measuring, 872 control, 872 controlling vibration, 889 cross transmission between rooms, 888 design room level, 875 duct sound absorbers, 880 duct system attenuation, 879 fans, 876 general problem, 872 grille, 874 Intakes, 664 kinds of, 874 levels, 875 loudness, 876 measurement, 871 plenum absorption, 685 through building construc tion, 888 `' transmitted through ducts, 874 unit of measurement, 871 Nozsle flow, 75, 78 Nurseries for premature in fants, 140 air conditioning equipment, 141 air conditioning requirements, HI Index to Technical Data Section o Odors, 111, 113, 147, 158, 950 human body. 111 . oil, oils analysis, 327 calorific value, 329 classification of, 326 combustion index,'332 combustion of. 330, 336 estimating consumption, 423 Oil burners, 361 boiler settings, 367 . classification, 361 . combustion adjustments, 366 combustion process, 365 controls, 368, 842 domestic, 361 furnace design, 366 gun type, 361 measurement of efficiency of . combustion, 367 mechanical draft, 361 operating requirements, 365 rotary type, 362 vaporizing type, 363 One-pipe system, 469, 516 gravity air-vent, 471 hot water, 516 steam, 6 ' - supply riser, 6 unit heater connection, 561 vapor, 472 Opening, openings air supply noises, 885 stacks, 226 types of, 224 doors, 225 roof ventilators, 225 skylights, 225 windows, 225 . Operating rooms, 138 .. conditions, 139 , reducing explosion hazard, 138 sterilization of air in, 140 Operative temperature, 852 Orifice discharge, 75, 480, 517 flow, 75 formuku, 77, 1045 heating systems, 478 Orsat apparatus, 1053 Outdoor air, 112, 629, 998, 1003 Outlet, outlets air supply noises, 885 ceiling, 658 duct approaches, 661 location, 450, 659, 664 performance, 655, 659 selection, 658 side outlets, 662 sound absorbers, 885 types, 657 wall outlets, 657 Outside temperature, 235, 261 Overhead distribution, 623, 1031 Overhead system, 6, 623 Oxygen chambers, 142 tents, 142 ^ therapy, 145 Ozone, 113 P Panel heating, 541 application methods, 541 Panel heating (continued) calculation principles, 544 electric, 544 . hot water, 541 steam, 541 . warm air, 463, 543 Panel radiator, 6 Particle size chart, 153 Perfect gas relationships, 27 Perforated ceilings, 658 Perforated outlets, 657, 658 Permeability, 200, 205 Permeance, 200, 203, 205 pH value, 906, 910 Phon. 871 Physical impurities in air, 113 Physiological principles, HI Pipe coils, 532, 541 heat emission, 532 wall, 532 : Pipe, piping. 585 capacity, 466-491, 513, 1013 coatings, 918 coil connections, 508 - coil output, 532 cold water, 1013 commercial dimensions, 585 conduits for, 621 connection to bating units, 496, 508 - corrosion, 912, 918 design, hot water system, 513 dimensions, 585 economical thickness insula tion, 615 expansion, 590 fittings, 592 fitting equivalent, 485, 513, 1019, 1020 flexibility, 590 ' forced circulation, 518 hangers, 591 heat losses, 603 hot water heating systems, 518 - inside dimensions, 586 insulation prevent freezing, 613 low temperature insulation, 612 materials, 585, 918 one-pipe forced circulation, 521 one-pipe gravity circulation, 521 one-pipe vapor, 491 overhead distribution, 473, 623, 1031 sizes, 479, 483 high pressure steam, 487 hot water forced circulation, 521,523 . hot water gravity circula tion, 521, 522 indirect heating units, 494 low pressure, 485 maximum velocity, 483, 518 one pipe riser, 486,492 orifice systems, 479 pressure drop, 482, 486-492 sub-4a5t4mospheric systems, tables for, 482-491 . two-pipe forced circulation, 523 two-pipe gravity circula tion, 522 two-pipe riser, 486 two-pipe vapor systems, 492 vacuum systems, 493 water supply systems, 1013 steam distribution, 469, 619, 623 steam heating systems, 463 supports, 591 . symbols for drawings, 17 tax. 382-385 XIX Pipe, piping (continued) sizes (continued) ' . thread connections, 591 ' threads, 591 tunnels, 623 underground insulation, 620 unit heater connections, 470, 510 water supply. 1013 - Pitot tubes, 64, 1043 Plate cell, 885 Plenum absorbers, 885 Plenum chamber, 6 Pneumatic control systems, 839 Pollution of air, 151 Polyphase motors, 859 Ponds, 749 Poatentiometer, 6 Power, 7 ' Precipitators, 727, 735 Pre-cooling, 639 Premature infant nurseries, 140 Pressure absolute, 7 atmospheric, 1 gages, 1025 loss, water supply piping. 1015-1021 measurement, 1041 barometer, 1042 .. regulators, 494, 622, 623, 840 static, 7 taps, 83 total, 7 vapor, 7 velocity, 7 Prime surface (see Beating Sur face), 9 Propeller fan, 705, 721 Protective coatings, 918 Psychrometer, 7, 1049 Psychrometric chart, 51,124 Pump, pumps condensate return, 498 mechanical circulators, 512 vacuum heating, 498 . controls, 499 piston displacement, 499 Pyrometer, 7,1040 optical, 1040 radiation, 1040 R Radial flow fan, 705 Radiant drying, 9S8 Radiant heating, (see Pond Heating) Radiation, 7 - baseboard, 532 equation, 92 - load, 385 shape factor, 95, 545 . Radiator, radiators, 7, 529 baseboard, 532 codes, 531, 1057 concealed, 539 connections, 507 correction factor, 536 ' direct, 7 effect of paint, 536 enclosed, 539 gas-fired, 370 heat emission of, 529 heating, 538 heating effect, 536 output of, 530 Heating Ventilating Air Conditioning Guide. 1952 Radiator, radiators (con tinued) panel, 6 ratings, 530 recessed, 7, 539 tube, 530 types of, 530 warm air, 370 Railway air conditioning* 997 air cleaning, 998 . air distribution, 998 heating, 997 humidity control, 1000 refrigeration, 998 summer systems, 998 temperature control, 1000 ventilation, 999 winter systems, 997 Reciprocating compressors, 813 Recooling, 629 Rectangular duct equivalents, 673 Reducing valves, 494, 622 Reflective insulation, 170, 180 Refrigerant* refrigerants, 8, 793 dichlorodifluoromethane, 793, 795 feeds, 771, 772 . monochlorodifluordmethane, 793, 797 monofluorotrichloromethane, 793, 798 pipe sire, 821 _ water, 805, 809 Refrigeration, 791, 998, 1002, 1009 absorption system, 807 air cycle, 804 ammonia, 822 basic concepts, 791 complex cycles, 803 compressors, 813-816 conaensers (see Condensers), 816 control, 818 coolers, 817 definitions, 791 discharge pressure, 601 equipment selection, 813 evaporators, 817 expansion valves, 819 float valves, 819 heat pump, 811 ice systems, 809 load, 257 mechanical, 791,993, 1002,1009 piping, 821 - reverse cycle, 792, 811 ship, 1009 simple cycle, 804 steam jet, 805 subcooling, 802 suction, 801 superheating, 802 symbols for drawing, 17 theory, 791 - ton of, 8, 791 types of compressors (see Com pressors), 813-816 vapor compression cycle, 796 water jacket, 801 Regain, 944 control of, 944 _ hygroscopic materials, 946 static, 690 Register, registers. (see OrHies), 439, 441, 450, 646 air supply noises, 686, 885 R eglster, registers (continued) mechanical furnace systems, 450 noises, 885 selection, 439, 451, 658 Reheat, 632, 640 Reheating, 632, 640 Relative humidity, 5,25; 52,1049 measurement of, 1049 Repulsion induction motors, 858, 863 Ship heating, ventilation, air conditioning (continued) factors affecting design, 1006 general consideration,1006 heating, 1007 ' insulation of hull, 1006 ducts, 1007 . refrigeration, 1009 requirements for space, 1009 bakery, 1008 bath, 1008 Residence control systems, 842 air conditioning, 844 coal-fired heating plant, 842 domestic hot water supply* 1031 cooling methods, 466 gravity furnace systems, 439 heat loss problems, 255 hot water heating system, 511 mechanical furnace system* 449 steam heating system, 469 Resistance thermometers, 1040 Resistors, 893 Return grille. 441, 888 mains. 8, 469, 489, 491, 513-516 openings, 441, 664 Reverse cycle refrigeration, 792, 811 Reversed return system, 8, 518 Roof* roofs heat flow through, 173,193-196, 275*279 .. time lag of solar radiation, 274 ventilators, 225 Room air motion, 647, 654 control, 843 # cross transmissionfnoiae, 888 latent heat, 633 noise level, 875 operating, 138 sensible heat, 633 Rotary dryer, 990 Rotary oil burner, 362 Run-around system, 640 s Sanitary ventilation,*132 Saturated air, 1, 25, 29 Saturation, 8 degree of, 8, 29 pressure, 7 Scale, 895 ' cause and prevention, 901 closed systems, 907 heating systems, 908 high temperature, 908 open systems, 908 Secondary air, 324, 341, 371 Sectional boiler, 378 Sensible cooling, 639 Sensible heat. 257, 266, 303-309, 313, 633, 644 factor, 633 gain, 257, 303-309 loss, 248 Sheet metal gages, 697 Shipheating, ventilation, air conditioning, 1006 air conditioning, 1006 design conditions, 1007 XX Siley, 1008 undry, 1008 living, 1008 machinery, 1007 shower, 1008 storeroom, 1009 toilets, 1008 washroom. 1008 ' systems, typical, 1010 ventilating, 1007 Silica gel, 831 Silicon dioxide, 831 Single phase motors, 862 Slime, 909 ` cause and prevention, 909,911 formers, 909 Slotted outlets, 649 Sludge, 901 cause and prevention* 905 Smoke, 8, 154, 322 abatement, 154, 322 density measurements, 1037 Smokeless arch, 8 Smokeless combustion, 322 Solar constant, 8, 266 Split systems, 8 Splitter dampers, 662 Spray . apparatus, 741 booths, 962 cooling, 745 ` cooling ponds, 749 cooling towers, 751 dehumidifier, 633, 745 distribution, 747 dryer, 991 equipment, 741 generation, 741 humidifiers. 743, 747, 748 unit air conditioner, 575 Spread, air distribution, 647, 652 Square foot of besting surface, 8 Squeeze dampers, 662 Squirrel-cage induction motor, 858, 859, 866 Solar heat, 266 absorbed by glass, 286 altitude, 266 calculation tables, 267-282, 286 through shaded windows, 297, 298 time lag, 274 transmission of, 278 through glass, 288 through roofs, 280 through walls, 282 Solar beat gain, 286 basic principles, 286 design for figured rolled glass, 291 ' design for flat glass, 289 design for glass block* 292 deviation from design, 297 shading glass, 297 . Solar radiation. 266 absorption of, 268 magnitude, 266 Solar water heater,.1033 Sol-Air temperature, 271, 273 Index to Technical Data Section Soot, 151,. 322, 340 Sorbents, 829 absorbents, 829, 830 adsorbents, 829 Sound (see Noise), 871 absorbers, 874 apparatus for measuring, 872 attenuation, 874, 879 control, 871, 889 cross transmission between rooms, 888 general problem, 872 duct absorbers, 880 intensity, 871 isolation, 576 levels, 645, 872 measurement, 872 outlet absorbers, 885 pressure, 871 unit, 871 ' Space heaters, 398 design, 399 Stack, stacks, 213,226,403,439, 442 height, 8, 228 wall, 439, 442 . smoke, 403 ' ' Standard, standards, 1057 air distribution, 645 atmosphere, 63 Standard air, 1 Static electricity elimination, 948 - pressure, 7. 683,706-115 regain, 690 '. Steady flow, energy equation, 24, 67 Steam, 8 coils, 769, 776. . distribution piping, 479, 619 estimating consumption, 435, 627 flow, 481, 482- flow measurement, 78, 625 heated equipment, 304 heating systems, 469 condensate return, 469 connections to units, 508 control valves, 509 corrosion, 908 drips, 505 flash leg, 506 gravity one-pipe air-vent, 471 gravity return, 469 high pressure steam, 473 low pressure steam, 473 mechanical return, 469 one-pipe, 470 orifice, 478 piping for, 479 sub-atmospheric, 477 two-pipe, 472 vacuum, 476 vapor, 474 let type of compressor, 805 meters, 78, 625 panel heating, 541 pipe capacities, 482,486-491 properties, 32, 49 rates, 627 reducing valves, 494 requirements, 435, 627 runout, 471 superheated, 8 tables, 32, 49 traps, 500 _ valves, 509 Steel boilers, 378 Sterilization of air, 132 Stoker, stokers, 353 . classification of, 353 Stoker, Stokers, (continued) . combustion adjustments, 353 combustion process, 355 controls, 361 furnace design, 359 . mechanical, 353 overfeed fiat grate, 357 overfeed inclined grate, 355 sizing and ratings, 360 underfeed, 356 ' Sub-atmospheric systems, 477 Summer air conditioning sys tem, 257, 467, 629 . Summer comfort, 127, 128 ' Superheated steam, 8 Supply mains* 8 Supply openings, 450, 648, 657, 885, 999 , measurement of velocities, 1047 Supports, pipe, 591 Tables (continued) climatic conditions, 235, 261 coal analyses, 318 coal classification, 319 codes, 1057 coil capacity balance, 779 combustible elements and compounds, 342 combustion rates, 386 comfort ranges, 123 condenser design data, 764 conductanoe, 93, 170, 180 air space, 170, 180 conduction problem solution, 101, 107 conductivity materials, 9t, 170, 175. 176, 180 convection conductances, 93 convector correction factors, 536 conversion equations, 15 conveying velocity, 963 Surface cooling coil arrangements, 778 condensation, 199,.612 cooling tower pipe size, 1022 conductance, 3, 170, 179 coefficients, 92,179, 610 external pipe, 605 heating, 9 . copper elbowequivalents, 513 copper tube capacity, 516 copper tube surface, 605 correction factor, temperature, extended, 9 434, 534, 559 temperature, 198,397, 549, 1039 Suspended unit heater, 556 corrosion resistance, 967 cost of air conditioning, 924 decibel scale, 873 . Symbols, 12, 13, 14 air conditioning, 21 for drawings, 17 degree-days for cities, 429 design dry- and wet-bulb tem peratures, 235, 256, 259, 279, 924,1007 heating, 18 piping, 17 ventilating, 19 design humidity, 924-944 dew-point, fuels, 350 ' draft in chimneys, 415 draft requirements of appli T ances, 415 duct attenuation, 879 duct combinations, 451* 452 Tables air changes, 218 air conditioning temperaturer. and humidities, 933 934 944 . . air duct size, 442 air leakage, 214, 216, 217 air requirements, 113 air, volume of, 32 allowable concentration gases, vapors, 158 oust, fumes, ICO, 161 altitude, pressure and tem- ' perature* 63 analytical solutions for heat conduction, 107 anthracite size, 320 atmospheric gas, 905 atmospheric impurities, 153, 905 attenuation between grille and room, 881 data, lining board, 883 in straight ducts, 879 of branches, 880 of elbows, 880 of plate absorber, 884 azimuth angle, 266 black body radiation, 96 boiler ratings, 380, 381, 383 bonnet pressure, 463 building load factors. 438 calorific value, 318,319,329,334 capacity constants, unit heat ers, 559 capture velocities, 957 carbon dioxide maximum, 345 cast-iron boiler rating, 383 ceiling temperature, 242 chimney draft, 415 circular equivalents of rec tangular ducts, 674 classification of coals, 319 motors, 858 water, 902 duct joints, 696 . duct sizing, 442, 443, 445, 446, 454, 459. 460. 958, 960 duct velocity 686 duct weight, 697. 698, 965 dust concentration, 155 elbow attenuation 880 elbow equivalent , 513, 966', 1020 emissivity factors, 3 end reflection, 884 # environmental conditions, limits, 118 equivalent Sue sizes, 417 equivalent length of fittings 443. 456, 485, 1021 equivalent temperature dif ferentials, 280, 282 exhaust pipes for machines* 958. 960 exhaust velocities, 957 expansion tank uses, 526 fan outlet velocity, 718 fan speed, 718 fitting allowance, 443, 456, 485 fitting dimensions* 593-596 fixture flow, 1014 fixture units, 1014 flammability of gases and vapors, 162 - flanged fittings surface, 606 flue gas dewpoint, 350 free convection, 94 friction loss, pipe, 513-516, 1016-1018 friction valves and fittings, 443, 456, 485, 1021 . fuel consumption, 434, 435 fuel oil properties, 328 . fumes, concentration, 160 gas piping capacity, 372 gaseous fuel properties, 334 glass absorptance, 288 glass transmittance, 288 graphical symbols, 17 heat absorbed, cooling water* . 759 XXX Heating , Ventilating Air Conditioning Guide 1952 Tables (continued) beat conductance, 93, 101, 170, 171-175 beat equivalents, 251 heat flow walls and roofs, 276, 280 beat gain appliances, 304 glass, 290, 292 glass blocks, 293,296 n. insulated cold pipes, 613 beat loss bare copper pipe, 604 bare steel pipe, 532, 604 basement, 245 pipe coils, 532 radiation. 96 best transmission coefficients, 186 building construction, 185 197, 284 doors, 197 glass, 197 roofs, 194, 284 walls, 186 water heaters, 1030 hot water demand, 1023, 1024, 1026 , hot water pipe sizes, 513-516, 1016-1018 humidities, industrial air con ditioning, 934-944 incident angle, 269 _ infiltration through outside doors, 217 infiltration through walls, 214 infiltration through windows, 216 inflammability, gases, 162 inside temperatures, 241, 258, 934,1007 # instantaneous solar heat gain, 266 insulation conductivity, 606 insulation factors, 606 insulation thickness, 613, 615 - insulation to prevent freeing, 615 insulation, underground, 617 intake velocity, 663 iron elbow equivalents, 513 life of equipment, 925 limits for contaminants, 158 163 ' load factors, 438 cost, 927 maximum allowable concen- ' trations - dust, fumes, mists, 160 dusts, 160, 161 flammable gases, 162 gases, 158 vapors, 158 metal gages for ducts, 696, 965 meter performance, 1020 'minimum outdoor air require ments toremove odoTs, 113 moisture content for mate rials, 946 ' moisture regain, 946 moisture transfer, 200 motor classification, 858 - motor current, 859 motor design limits, 856 motor drive applications, 862 motor horsepower, 856 motor ratings, 864 ' motor speed range, 856 motor voltage, 856 noise levels, 875 - oil fuel specifications, 328 oil heat value, 329 ' operating conditions, 826 operating hours, 930 orifice capacities, 480, 517 outdoor air requirement, 113 outlet velocities, 558, 718 outside temperature, 235, 261 owning and operating cost, 926 particle size, 153, 154 particulate matter, size, 153 Tables (continued) periodic heat flow. 276 permeability to vapor, 205 physiological response to heat, 117 pipe capacity, 372, 482, 484, - 486,514, 822,960,1022 pipe covering factors, 606 pipe dimensions, 586-588 pipe expansion, 589 pipe fitting dimensions, 593 600 pipe roughness, 73 pipe surface, 605 pipe volume, 527 pressure loss . ducts, 464 elbows, 513 fittings, 485, 513 refrigerant line, 822, 823 registers, 461, 462 return intake, 664 properties of air, 32, 342 . dichlorodifiuoromethane, 795 'fuel oil, 328 gaseous fuels, 334 moist air, 32 ' monochlorodifluoro- methane, 797 monofluorotrichloro- methane, 798 steam, 49 water, 40 radiation, black body, 96 radiation factors, 95 radiation problem solution, 97 radiator neat loss correction factors, 534 radiator sizes, 530, 531 rating air conditioning units, 579 rating steel boilers, 380 ratio of specific heats, 73 . refrigerant properties, - 795, 797, 798 . . refrigerant line capacity, 822, 823, 826 refrigeration equipment selec tion, 826 regain of hygroeoopic mate rials, 946 ' requirements for fuel oil, 328 return pipe capacities, 488, 491 room temperature differential, 242 screen mesh, 154 . shading effect, 268 sheet metal gages for ducts, 696, 965 ship design conditions, 1007 slime control, 911 slime formers, 603 smoke chart numbers, 1053 sodium dichromate, 914 soil conductivity, 176 sol-air temperature, 273, 279 solar altitude, 267, 270 . solar declination, 270 solar beater design, 1035 solar heat gain, 280, 283, 290 solar radiation, 267, 269 sound attenuation, 879, 880, 881, 883, 884 sound level, 875, 876 specific gravity factors, 373 specific neat of compressible fluids, 73 specific heat ratio, 73 spray pond design data, 751 steady-state conduction prob lems, 101 steam consumption of build ings, 436 steam pipe capacities, 482, 483, 486, 490 steam table, 49 steel boiler ratings, 380, 381 summer climatic conditions, 261 XXII Tables (continued) . summer design conditions, 258, 261 surface conductance, 93, 170 temperature differential, 242 temperature, industrial air conditioning, 259 temperature, inside, 258, 259, 933 a temperature limit for'men, 118 temperature range, 260 * temperatuie( summer, 261 temperature, winter, 235 thermal conduction problems, 107, 113 thermal conductivity, 91, 606 thermal convection conduc tance, 93 ^ thermodynamic properties moist air, 32 water, 40 . transmittance, glass, 288 unit conditioner rating, 579 unit fuel consumption, 434 unit heater capacity factors, 559 . unit heater velocities, 558 unit ventilator capacities, 567 upper temperature limits, 118 vanes in elbows, 681 velocity, return intake, 663 ventilation standards, 265 warm air ducts, 442, 443, 445, 446, 451, 454, 459, 460 warm air fittings, 443 warming-up allowance, 385 - water analyses, 902, 903, 904, 921 ' watercooling effectiveness, 759 water fixture flow, 1014 water main temperatures, 744 water meter performance, 1020 water pipe capacities, 514, 516 water requirements, 1023,1024, 1026 weight of air, 32 - weights of ducts, 697-698 . winter climatic conditions, 235 winter design temperatures, 235 Tank, expansion, 524 Tax, pipe, 384,- 385 Temperature, temperatures absolute, 9, 30 ' ' attic, 243 ' automatic control, 839, 846 basement, 245 " control for railway passenger car, 1000 ; control service water, 1031 design wet-bulbj 757 dew-point, 26' - dry-bulb, 9 drying, 934, 984 ' effective, 9,122-128 ground, 244 . '' hazard, 117 ' industrial, 259, 934-944 inside, 241, 258, 1007 fellings, high, 241 proper level, 241 mean radiant, 120, 548 measurement, 1037 thermocouple, 1038 thermometers,. 1037 outside, 235, 261 surface, 396, 1040 ' thermodynamic wet-bulb, 26 unbeated spaces, 244 water main, 744 wet-bulb, 9 ' Terminology, 1 Test methods, 1037, 1057 Index to Technical Data Section Testing codes, 1057 Therapy ' cold, 143 fever, 142 oxygen, 145 Thermal conductance, 167, 170, 180 conduction equation, 90 conductivity, 90, 168 convection, 89, 91 ' convection equation, 91 expansion of pipe, 590 interchanges of body, 113 radiation equation, 92 resistance, 8, 167, 170, 180 resistivity, 8, 170,180 steady-state conduction prob lems, 101 transmittance, 247 unit conductances for convec tion, 93 . . Thermocouples, 1038 Thermodynamics, 23 air and water mixture, 23 laws of, 9 wet-bulb temperature, 26 Thermometers, 1037 alcohol, 1037 dry-bulb, 1037 globe, 537, 1052 Kata, 537, HM8 mercurial, 1031 resistance, 1040 stem correction, 1037 wet-bulb, 1049 Thermostat, 9. 840 room, 840 Time lag through walla and roofs, 274 Ton of refrigeration, 8 Total he&t, 5 Total pressure, 7 Tower, towers, 751 ` cooling, design, 758 cooling, performance, 760 mechanical draft, 753 natural draft, 752 selection, 763 spray cooling, 751 u Ultra-violet light, 113,132,153 Underfeed stoker, 354 Underground pipe insulation. 622 Unbeated space temperatures. Unit, units air cleaners, 723, 735 air conditioners, 571 application, 578 cooling, 581 dehumidifying, 576 humidifying, 575 ratings, 579 types of, 571 air coolers, 571, 581 defrosting, 584 design, 581 performance, 581 ratings, 582 types of, 571 air filters, 723 British thermal, 2 dehumidification, 576 direct-indirect hating 3 fuel consumption, 423 heaters, 555 application, 557 boiler capacity, 564 capacity factors, 564 control, 561, 846 direct-fired, 353, 377, 555 electric, 558 piping connections, 562 ratings, 558 temperatures, 549, 550 types of, 555 humidifiers, 748 . types of, 748 induction, 637 noise measurement, 871 . systems, 555, 569 ventilators, 564 air exhaust vents, 569 applications, 568 . capacity, 567 v control, 839 ratings, 567 window, 570 Unitary equipment, 555 definitions, 555 Vapor, vapors, 151 barrier, 207 heating systems, 10, 474 '"it neater connection, 562: Pressure, 7 transmission, 200 . Vaporizing oil burner, 362 'Velocity, 10 capture, 957 coil, 575 conveying, 963 duct, 686 . exhaust intakes, 664, 957. 063 hood, 957, 963 pressure, 7* . reduction method, 687' return grilles, 664 unit heater, 555, 556 Ventilation, 10, 260 animal shelters, 227-230 ' dairy stables, 223 garages, 231 living space, 209 natural, 220 . general rules, 226 passenger bus in summer, 1002 railway passenger car, 997 . rules, 226 ship, 1007 ' symbols for drawings, 17 systems, 629 , walls and attics, 210 wind forces, 220' Ventilator, ventilators. 225 control, 226 roof, 225 unit, 564, 846 control, 846 window, 570 Vertical blow unit heater, 556 Vertical openings, 219 fifrnlipg 219 Vibration, machine, 889 Viscous filters, 725 automatic, 726 impingement, 725 Vitiation of air. 111 Volume control, 663 furnace, 360, 367 specific, 10 Transmission ' heat losses, 247 . solar heat, 279 Transmittance, thermal, 9 Transportation air conditioning, temperature and humidity control, 1000, 1001, 1003, 1010 ' automatic return, 475, 504 bucket, 502 float, 500 impulse, 503 steam, 500 . thermostatic, 501 tilting, 503 Traveling-grate stoker, 355, 357 .Treatment of disease, 131 Tropical air cooling, 136 Tube radiator, 7 Tunnel dryer, 990 T unnels, pipe, 623 Twamg vane, 657, 661, 679, 681 iwo-pipe system, 9, 472, 516 V Vacuum cooling units, 805 beating pumps, 460, 498 control, 499 piston displacement, 499 heating system, 9, 469 down-feed, 474 unit heater connection. 510. 562 Vacuum dryer, 988 Valve, valves, 508, 509, 600 automatic, 601 check, 601 control, 509 expansion, 619 gate, 600 globe, 600 reducing pressure, 494 Vane, vanes, 653, 662. 681 Vaned outlets, 653, 657 XX1U w Wal), walls beat flow through. 186-190 247,271 * heat transfer coefficients, 89 . 186-190 ' infiltration through, 213 time lag of solar radiation, 274 Warm air gravity heating system, 489 combination carrying caparity, 445 design procedure, 446 furnace capacity, 393 installation practice, 439 .standardized combinations 442 mechanical heating systems, automatic control, 393, 458 cooling methods, 466 continuous circulation, 463 dampers, 451 design procedure, 452 ducts, 451 Heating Ventilating Air Conditioning Guide 1952 Vann air (continual) Mechanical heating systems {continued) fans, 392, 463 filters, 392 furnace, 391 heavy duty, 392 - selection. 463 humidification, Urge systems,JM - registers and gniles* w standard combinations, 451, 452 . panel heating, 463 radiators, 370 Water {continued) 'heating. 896, 1026 load, 1023 make-up, 764 . maximum main temperature, 744 meters, 1618. WJ9 mineralised, 902 .. properties of. 40 . services, 1013 arrangement, 1031 temperature control. 1031 thermodynamic properties of, Window, windows ,. Wcoefficients of transmission. 197 SdLtiou through, 286 ventilators, 570 WSreconditioning system, Q29 comfort gone,. 124 freezing equipment /o* Wound rotor motor, 8W Wrought-irou Pipe, 585 Wrought-steel pipe. 585 Y Washer, washers,' 741 air, 1, 741 Water ESSsS," meat, 741, 751 characteristics, classification, 902 cnlls. 761, 1027 . wntTOl temperature service, 1031 cooled condenser, 816 corrosion treatment, 90 demand, 1013 _ _ faucets. 1014, 1019 . fittings, loss, 1018. 1019 fixtures, 1014 fixture unite, .1014 formed depoeits. 801 ' hMnd-fired, 1086 . solar, 1033 , treating chemicals, Ml, 919 well temperatures, 746 Water vapor. 25. 32, 40, 198 saturation pressure, 25, 4U specific enthalpy, 4 specific volume. 10.40 surface condensation, 199 Welding. 585 Year-round air conditioning system* 629 ga^Tmethods,^ SuST^ment.eM installation. 630 location of apparatus, 642 selection, 640 z wctrbx--pr4u?56,(TM Wet return, 8, 469 7nnc control, 630 _ Zone of evaporative regulation, 115 ' Wind, winds fdM toltock efiect, 213 natural drsiteqmpmeiit751 selection of, velocity, 234, 4bu Zoning. 630 control. 630, 844 recooling, 631 reheat, 631 volume control, dm XXIV CHAPTER 1 TERMINOLOGY 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., 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 the actual value of this acceleration at sea level and about 45 deg latitude. Adiabatic: An adjective descriptive of a process such that no heat is added to, or taken from, a substance or system 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., 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 all, or 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 0.075 lb per cu ft and an absolute viscosity of 1.22 X 10~` 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 m 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 2 CHAPTER 1 1952sGuide ; Blast Heater: A set of heat transfer coils or sections used to heat air which is drawn or foi-ced through it by a fan. : i . 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 heating surface within the flues. . Boiler Horsepower: The equivalent evaporation of 34.5 lb of water per hr from and at 212 F. This is equal to a heat 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 i 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 gram 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 29.) 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 feel comfortable. (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 Terminology 3 heat. Condensation of steam or water vapor is effected in either steam 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 for a 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 difference. Common unit is: Btu per (hour) (square foot) (Fahrenheit degree). Symbol C. : Conduction, Thermal: The process of heat transfer through a material medium in which kinetic energy is transmitted by the particles of the material from particle to particle without gross displacement of the particles. - .. Conductivity, Thermal: The time rate of heat flow through unit area of a homo geneous substance under the influence of a unit temperature gradient.. Common units are: Btu per (hour) (square foot) (Fahrenheit degree per inch). Symbol k. Conductor, Thermal: A material which readily transmits heat by means of con duction: . 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 botil 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 22.) 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, Pi. being the larger, is: db difference = 10 logioPi/Pi- . In acoustics the threshold of hearing at 1,000 cycles per sec has been standardized at 10"le watts per sq cm. If Pi is the power in watts per square centimeter of a ' measured sound, then 10 logio Pi/10-1* 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 below. 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 crystallization 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. 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 bv the water is the shortest feasible, and so that there are considerable differences in the lengths of the several circuits composing the system. Down-Feed One-Pipe Riser (Steam): A pipe which carries steam downward to the heating units and into which the condensate from the heating units drains. 4 CHAPTER 1 . 1952 Guide Down-Feed System {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. t Diy: 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.) . Electric Heating Element: A unit assembly consisting of a resistor, insulated sup ports, and terminals for connecting the resistor to electric power. Enthalpy: A term used in lieu of total heat or heat content. Expressible in Btu per pound. Mathematically defined as h -- u + pv/J. When a change occurs at con stant pressure, as when water is boiled, the change in enthalpy is equal to tbe 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 = fdQ/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 Bubstance 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 Terminology 5 manifestly ineffective (i.e.r 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, it is the cubical contents of the furnace, flues and combustion chamber, up to the plane of first entry into the tubes. (A.S.M.E. 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 be 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 form of 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 oTdry 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 (Cy) 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.) Heater, Electric: A complete assembly of heating elements with their enclosure ready for installation in service. ,. 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. Humidlstat: 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 grains per cubic centimeter. , Humidity, Relative: The ratio of the mol fraction of water vapor in a mixture to T0* *racti.on of water vapor in saturated air at the same dry-bulb temperature ana 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 iquia water 1 in. high at a standard temperature. The standard.temperature is r 6 CHAPTER 1 1952 Guide sometimes taken as 0 C and sometimes as 62 F. One inch of water at 62 F = 5.197 lb per sq ft. . . Insulation (Thermal): A material having a relatively high resistance to heat flow, and used principally to retard the flow of heat. . . Isobaric: An adjective used to indicate a change taking place at constant pressure. Isothermal: An adjective used to indicate a change taking place at constant temperature. Load, Estimated Design: In a heating or cooling system, the'sum of the useful heat transfer, plus heat transfer from or to the connected piping, plus heat transfer occurring in any auxiliary apparatus connected1 to the system. The units are Btu per hour or, in heating, equivalent direct radiation (EDR). .Load, Estimated Maximum: In a heating or cooling system, the calculated maxi mum heat transfer that the system will be called upon to provide. . 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 pressure 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 equal 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, -m F/a. The common units of mass are the gram and the pound. . ;. Mechanical Equivalent of Heat: The quantity of mechanical energy equal to,one unit of heat. J = 778.3 ft-lb per Btu = 4.187 X 107 ergs per gram-calorie. . . 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. -. . 1 .. Micron: A unit of length, the thousandth part of 1 mm or the millionth of a1 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 KP'psi. Mol: A weight of 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-.1Gram 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 ft3), /or 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 (ft3 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 heating unit there is but one connection which must serve as both the supply and the return, although separate supply and return connections may be used. (Hot Water)--A hot water system in which the cooled water from the heating units is returned to the supply main. Consequently, the heating units far thest from the boiler are supplied with cooler water than those near the boiler in the same circuit. ; '. . . Overhead System: Any steam or hot water system in which the supply main is above the heating unit. In a steam system the return must be below the heating units; in a water system the return may be above or below the heating units. Panel Heating: A heating system in which heat is 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 Healing System. Plenum Chamber: An air compartment maintained under pressure, and connected to one or more distributing ducts. . -1 Terminology T: Potentiometer: An instrument for comparing small .electromotive forces, or-for1 measuring,small electromotive forces by comparison with a known electromotive: force.1 Its principal advantage is that during the measurement, no current flows1 . 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, granr 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 oyer 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. - ' 1 1 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 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 term Radiant Heating is fre quently used to include both Panel and 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 inay, 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. A A heating unit exposed to view within the room or space to be heated, t* ra ,lat,?r transfers heat by radiation to objects within visible range, and by conduc"'j? TM "}? surrounding air which in turn is circulated by natural convection; a sousage ra"la^or *s a*so a convector, but the term radiator has been established by long tho^a<^*a^ur'-Concea,ed: A heating device located within, adjacent to, or exterior to _ -r00lnl)e*n6 heated, but so covered or enclosed or concealed that the heat transfer ace of the device, which may be either a radiator or a convector, is not visible l - CHAPTER 1 1952 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 of heat while expanding or vaporising. . Refrigeration, Ton of: The removal of heat at a rate of 200 Btu per min, 12,000 Btu per hr, or 288,000 Btu per 24 hr. . Resistance, Thermal: The reciprocal of thermal 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-Return System: A system in which the heating or cooling medium from several heat transfer units is returned along paths arranged so that all circuits com posing the system or composing a major sub-division of it are of practically equal length. ~ Sabin: A unit of equivalent sound absorption equal to the equivalent absorption of one square foot 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 ora 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. 1 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 heated) 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. Wei Saturated Steam is steam at the saturation temperature corresponding to the pressure, and containing water particles in suspension. Superheated Steam is I ' ' 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 environment. 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: (1) 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 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 ot 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 foot) (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.* 1 h Xj5!fr'<iLiutll0If first stated laws are given in parentheses. 1 ra Glossary of Physics, by LeRoy Dougherty Weld (McGraw-Hill, 1937). CHAPTER 1 1952 Guide 10 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-Feed System: A heating system in which the supply mains are below the level of the heating units which they serve. < Vacuum Heating System: A two-pipe steam heating system equipped with the -necessary accessory apparatus which will permit operating the system below atmos p.heVraicnepRreasstiuor:e Iwnhaeinr ddiesstririebdu.ting devices the ratio of depth of vane to shortest open ing-Vwaipdothr: bTehtewegeansetowuos faodrjmaceonf tsugbrisllteanbcaerssw. hich 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- retVurenl.ocity: A vector quantity which denotes at once the time rate, an. d the direction of a linear motion. V = -- For uniform linear motion V = -- Common units dt t areV: efenetitlapteiorns:ecTohned.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 AiVr Cisocnodsiittiyo:niTngh.a) t propert.y 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- poiIsne bmeainngy 1f/o1r0m0uolaf s1 apbosisoelu. te 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' KceinnetimpoaistiecsvXisc2o.s4it2y =is vthisecroastiitoy ionf pabosuonldustepveisrcfoosoittyhtooutrh. e 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 visVcoolsuitmyein, Ssqpueacrieficfe: eTthpeervsoelucmoned.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 WvaariromusArior oHmesatoinf gthSeybsuteilmdi,nFgotrhcreodu:gAh dwuacrtms. air heating system in which circula tion of air iB 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 imbedded in 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 and 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 3, 4,12, 31, 35, and 46. . Absolute....................................................................................................................................... .abs ' Air horsepower................................................................... ...................................................... air hp Alternating-current (as adjective)..................................................................................... .-.a-c Ampere.................... .............................. .................................. ..........:.................................... ,. .amp Ampere-hour.............. ............................ .................................................................. ,........... amp-hr Atmosphere..................................................... ,.......................................... .............................. .atm Average..............................................................................................................................................avg Avoirdupois ............................................................................................ ...............avdp Barometer............................................................. bar. Boiling point.......................................................................................... bp Brake horsepower................................................................................................ bhp Brake horsepower-hour......................................................................................................... bbp-hr British thermal unit........................................................................................................... . . iBtu British thermal units per hour..............................................................................................Btuh Calorie................................................................................................................... ........................... cal Centigram................................................................. '.............. .................................. ................ eg Centimeter.............................................. cm Centimeter-gram-second (system)...........................................................................................cgs Cubic......................... .cu Cubic centimeter......................... ;...............................................................................cu cm or cc Cubic foot......... .......................... ......................................... .............................. CU ft Cubic feet per minute......................................... .................................... :..:.......... .....: '.cfm Cubic feet per second.'......................................................... ^................................................... cfs Decibel.................................... db Degree*..........................................................'............................................:......................... deg or Degree, Centigrade........................... ............................................................................................. C Degree, Fahrenheit............. . . ... .. ................... i ............ F Degree, Kelvin............................................................................................ K Degree, Reaumur.....................................................................................................-.............. .R Diameter.;,.................................................. ,diam Abbreviations for Scientific and Engineering Terms, Z10.1-1941 (Ameriocm Standards Annotation). _ y 18 recommended that the abbreviation for the temperature scale, F, C, K, R, be included in expres- 09 tor numerical temperatures but, wherever feasible, the abbreviation for degree be omitted, e-0-, 68 F. 11 12 CHAPTER 2 1952 Guide / - Direct-current (as adjective) .......................................................... :d-c Electromotive Force.................................................................................................................... emf Feet per minute.................................... fpm Feet per second................................................................................................................. fps Foot............................:.. .................................................................................................................... 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 .............................................. ............ 7............................. ihp Indicated horsepower-hour..7....................................!...................................................... ihp-hr Kilogram...................7...........:..............:...................................................... ............................ .kg Kilowatt.................. ........................7.7............. ....................................... ...kw Kilowatt-hour...................................................................................... kwhr Mass..7........................................................... mass Melting point.................................................................................................................................. mp Meter................................................................................................7. /....................................... ... .m Micron......................................................................... :. i......................................................a (mu) Miles per hour.......... ...................................................... ........................................................ : .mph Millimeter............................................ ............................'................ :..........................................mm Minute................................ ................,.................................'.............................................min Molecular weight....... .-......................................................... ............................'................. mol. wt Mol............................... ................................................................................................................. .. .mol Ounce............................................................................................................................................. .. .oz Pound.................................................................... .;.............................................................................lb Pounds per square inch............................................................................................... :............. psi Pounds per square inch, gage ... Pounds per square inch, absolute Revolutions per minute.................. Revolutions per second.................. Second.......... ........................................ Specific gravity Specific heat-- Square foot........ Square inch....... Watt.................... Watthour........... psig .psia .rpm . .rps . .sec sp gr .sp ht .sq ft sq in. .... w . .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.8 Additional symbols and variations in the standard symbols Letter Symbols for Mechanics of Solid Bodies, Z10.3-1942, imd Letter Symbols for Heat and Thermo dynamics, Z10.4-1943 (American Standards Association). , . Abbreviations and Symbols 13 found necessary in the individual chapters will be found in a list at the end of Chapters 3, 4, 12, 31, 35, and 46. , '' : ; ` 7 Acceleration, due to gravity................i......................... ..................................... ......................g Acceleration, linear........................... ,................. ..........:.............................................................. a Area..................................................................................................................................................... A Change in specific volume during vaporization,....................................... , .................... pt. Density, Weight'per unit volume, Specific weight.i.i........ .7 . .7d.brp (rho) Distance, linear,........................ ..........,......................'.................................................................. * Dry saturated vapor, Dry saturated gas at saturation pressure and temperature, vapor in contact with liquid............ :.............................................................. Subscript g Efficiency.................. ........................ ..........................................,.................................. 7............. n Elevation above some datum....... ........................................................................ .. 7 ... z, Z Emissivity............... ................................................................................. ............................ ............. e 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............................................................. ......................B Head...................... ...................................................... ........................................................... .. - H or A Heat content, Total heat, Enthalpy. (The capital should be used for any weight and the small letter for unit weight)......................................................H or h Heat content of saturated liquid, Total heat of saturated liquid, Enthalpy of saturated liquid, sometimes called heat of the liquid............................................... hi Heat content of dry saturated vapor, Total heat of dry saturated vapor, En thalpy of dry saturated vapor. 7........:................................................................... ____ ht Heat of vaporization at constant pressure...,...... ...................................... ... ... A or. At, Hydraulic radius..................................................... ............................................................;------Ba Internal energy, Intrinsic energy. (The capital should be used for any weight and the small letter for unit weight)... i............................................................. U or u Length of path of heat flow, thickness..................................................................................... L Load, total.......................................................................................................................................... W Mechanical efficiency.......................... ..................... ................ .................................................... Cm 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........................................................................................ ............. .Nr* Saturated liquid at saturation pressure and temperature, Liquid in contact with Specviaficpohre..a...t....................................................:.._.._._.._.._.._.._._...._.._.._.._.._._.._...7.................._._.:...........................................7..........................S.u.b..s...c..r.i.p...t cf Specific heat at constant pressure....................................................... .............................. . Cp Specific heat at constant volume........ ............................................... .... .....................:. ,c Specific volume, Volume per unit weight, Volume per unit mass.............. -y...........'.: .v Temperature (ordinary) F or C. . (Theta is used preferably only when t is used for Time in the same discussion).... .7.7....:.'..'..:.'...........................f or 9 {theta) Temperature (absolute) F abs or K. (Capital theta is used preferably only when small theta is used for ordinary temperature).......................... T or 9 {capital theta) Thermal conductance:* heat transferred per (unit time) (degree)................................C . c,, i=m B L ti -- fj ,r . * *^rma ending icily designate properties independent of eise or shape, sometimes called specific propertter. Examples: conductivity, resistivity. Terms ending ones designate quantities depending not only on the material, but also upon size and shape, sometimes called total quantities. - Examples: conductance, transmittance. Terms ending ion designate rate of heat transfer. Examples: conduction, transmission. 14 CHAPTER 2 1952 Guide Abbreviations and Symbols 15 `i- 1 Thermal conductance; per:unit 'area, Unit conductance:;heat transferredrper.... . (unit time) (unit area) (degree)......... ................................................................. ,C k a f CONVERSION EQUATIONS' Heat, Power and Work ' V A RA A(U - t.) L Thermal conductivity: heat transferred per (unit time) (unit area) (degree per unit' length)............................................................ ....................................................................k 1 ton refrigeration Latent heat of ice ' : . : / 12,000 Btu per hour 3 \ 200 Btu per minute = 143.4 Btu per pound . Q_ A k= (h -- ti) Surface coefficient of heat transfer, Film coefficient of heat transfer, Individual coefficient of heat transfer: heat transferred per (unit time) (unit area) .. (degree).................................................................................. :................ .} 9. s f 1 Btu : '` 1 Int. watthour . 1 Int. kilowatthour ' ' ( 778.3 ft-lt> = 1 0.2930 Int. whr I 252.0 I.T. calorie ............... . 2656 ft-lb I 3.413 Btu ' 3600 Int. joules 860 I.T. calories. ! y. f 3,413 Btu ! 3.517 lb water evaporated from. I and at 212 F A /= tl --- i . 1 Int. kilowatt (1000 watts) !! (In general f is not equal to k/L, where L is the actual thickness of the fluid film.) 1000 I.T. calories) S:t Overall coefficient of heat transfer, Thermal transmittance, per unit area: heat , 1 I.T. Kilocalorie/ . transferred per (unit time) (unit area) (degree overall)............. ............. ^ V f 1.341 hp 1 56.88 Btu per minute. . .. \ 44,267 ft-lb per minute (3.968 Btu 1 3088 ft-lb I 1.1628 Int. whr '. 1 A U= tl -- tl i: ` ' ' ' Thermal transmission (heat transferred per unit time). : a .- . 9=t ;; . . Thermal resistance (degree per unit of heat transferred per unit time).................... R - --=h g \_kA Thermal resistivity___ ____ ....... ................................;:.. 1-------- ........................ 1/k Vaporization values at constant! pressure, Differences between values for satu rated vapor and saturated liquid.at,the same pressure. - -Subscript fg Velocity.............................................................................................................. ........................ .V Viscosity, absolute.......... :...............:............. ,..................................... ......,..... it Viscosity, kinematic...............................................,.......................................'. ............ -n/p Volume (total)....................................................................... '.......................................... /......... V Voliune per unit time, Rate at which quantity of material passes through a, machine, Quantity of heat per unit tune, Quantity of heat per unit weight....q Weight of a major item. Total weight....................................................................................W- Weight rate, Weight per unit of power, Weight per unit,qf time.................................. to Work (total).......... ....;...... ........ . .......... -....... ...IV , THE GREEK ALPHABET ... !/ . . 1 horsepower 1 boiler horsepower Weight and Volume : 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 {0.7455 Int. kw 42.40 Btu per minute ' :; 33,000 ft-lb per minute 550 ft-lb per second / 33,475 Btu per hour \ 9.809 Int. kw ; ' ' ' I 231 cu in. .\ -0.1337 cu ft 277.42 cu in. / 7.481 gal \ 1728 cu in.,,. 62.37 lb 69.83 lb 8.338 lb 7.998 lb .. . /16oz ' \ 7000 grains 1.244 cu ft 2000 lb A a Alpha It Iota B 0 Beta K k Kappa T y Gamma A X Lambda A 6 . Delta M ft Mu E e Epsilon N v Nu Z f Zeta E| Xi , . ' H ij Eta 1 . ` O.o Omicron 0 68 Theta ; . II w Pi . . P p iRho . ; Su Sigma 1 : Tr Tau T v Upsilon $ <p 4> Phi Xx Chi . 'Sf^r Psi `. Q to Omega 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 * Checked in 1944 by ,Vaiuntal Bureau of Standards. Abbreviations Int. and"I.T. refer to International end International CSteam),Table,-rcspertively. . . 16 CHAPTER 2 1952 Guide 1 atmosphere 14.696 lb per square inch' 2116 lb per square foot 33.94 ft water at 62 F . 30.01 in. mercury at 62 F 29.921 in. mercury at 32 F X 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) ... ( 0.4330 lb per square inch \ 62.37-lb per square foot 1 in. mercury at 62 F (in vacuo) 1 in. mercury at 32 F (in vacuo) 0.4897 lb per square inch 17.835 oz per square inch 1.131 ft water at 62 F 13.57 in. water at 62 F . 0.49115 lb per square inch Metric Units 1 cm 1 in. 1m 1 ft 1 sq cm 1 sq in. 1 sq m 1 sq ft 1 cu cm 1 cu in. 1 cu m 1 cu ft 1 liter 1 kg 1 lb . i 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 .. 1 dyne. ... 1 absolute joule = 14.22 lb per square inch 0.03613 lb per cubic inch 62.43 lb per cubic foot = 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 l.T. calorie.per square centimeter =1.8 Btu per pound = 3.687 Btu per square-foot - 1 I.T. calorie per (second) (square centi ' 2903 BTU per (hour) (square foot) meter) for a; temperature gradient of 1 C. = for a temperature gradient of 1 F deg per centimeter deg per inch of thickness. 'Abbreviations and Symbols 17 GRAPHICAL SYMBOLS FOR DRAWINGS' ; Graphical Symbols for Drawings Pi-ping Heating 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 .. -FOR' -fov Alb 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--i-------------- C---------7-- CH -- -H- -D- --B-BR- Plumbing . 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 '- Sprinklers 42. Main Supplies 43. Branch and Head 44. Drain , frm: American Standard Graphical Symbols for Pipe Fittings, Valves, and'Piping (ASA fici 7TM and American Standard Graphical Symbols for Heating, Ventilating, and Air Conditioning on15r with the permission of the publisher, The American Society of Mechanical Engineer*, 29 West 39th St., New York *Cn. Y. 18 CHAPTER 2 Graphical Symbols for/Drawings,. /iJOb.'r-U-S . 1952 -Guide - Heating 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 Heatef (Centrifugal Fan), Plan XPA -- ----EZ3h ' Xw;. "t;.., 6 6--- = ---- I ~1 E-a -------- 1V1 X IREC1 ; 4 3--- = ---- .14. Unit Heater (Propeller), Plan 15. Unit Ventilator, Plan. . . .. , Abbreviations and Symbols Graphical Symbols for Drawings 16, Valves 16.1 Check ....... ... -v. . - 16.2 Diaphragm' -. V 16.3 Gate - 163 Globe . . ` ............... 16.5 Lock and Shield f 16.6 Motor Operated . . ' 16.7 Reducing Pressure ' 16.8 Relief (Either Pressure or Vacuum) 17. Vent Point' Graphical Symbols for Drawings 18. Access Door : 19. Adjustable Blank Off --~ 20. Adjustable Plaque 21. Automatic Dampers 19 ;Heating -- -- --CXI-- -- & VENT Ventilaiing ZZZ3-'- X. AD f TR 20X12 r P-20XI2-700Cpm H~r ,$ T P-20">-700 Cfm -W----- - Gjfl 22. Canvas Connections 20 CHAPTER 2 Graphical Symbols for Drawings 1952 Guide Ventilating 23. Deflecting Damper - tT -24. Direction of Elow.... e 25. Duct (1st Figure, Side Shown; 2nd Side - not Shown).............. 1 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 |^V-(E OR R 20X12) [XH-----------(S 20X12) p^-JlCR 20 X 12- 700 Cfm ld_dcG*0X 12 - 700 c^m TR-12X8 700C^m 30. Fan and .-Motor-With Belt Guard 4S&EE3 31. Inclined Drop in Respect to'-Air Flow 32. Inclined Rise in Respect to Air Flow 33. Intake Louvers on Screen 34 Louver Opening 35 Supply Outlet Ceiling (Indicate Type) 1 C iz VSr j L 20)^12-700 C^m 20* DIAM. 1000 C^m 36. Supply Outlet Wall (Indicate Type) r> TR - 12X8 700 cf m 37. Vanes 38. Volume Damper. - Abbreviations and Symbols Graphical Symbols for Drawings 39. Capillary Tube------ WNAA/-" 40. Compressor 5 41. Compressor, Enclosed, Crankcase, Ro tary, Belted o 42. Compressor, Open Crank case, Recipro cating, Belted 43. Compressor, Open Crank case, Reciproeating. Direct Drive 44. Condenser, Air Cooled, Finned, Forced Air 45. Condenser, Air Cooled, Finned, Static 46. Condenser, Water Cooled, . Concentric. Tube in a Tube 47. Condenser, . Water Cooled. --'TOTH-- Shell and Coil 48. Condenser, Water Cooled, . Shell and Tube 49/ Condensing Unit, Air Cooled -P6- 50. Condensing Unit, Water Cooled L6t- 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 21 Air Conditioning 57. Evaporator Mani- . folded, Finned, Gravity Air ' 58. Evaporator, Plate Coils, Headered or Manifold . 59. Filter, Line 60. Filter & ` Strainer, Line 61. Finned Type Cool- . ing Unit, Natural Convection 62. Forced . Convec tion Cooling Unit Hill11' "" + y C 11 If I. ------ . _ ^1 . ) 63. Gage 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 6-6 '-6 sor, Sealed Crank . case. Recipro cating . 70. Motor-Compres sor, Sealed Crank case, Rotary --WAr*^)-AA/V-- 71. Pressurestat 72. Pressure Switch 73. Pressure Switch With High Pressure Cut-Out 74. Receiver, Horizontal -dD -rffh- d=S 75. Receiver, Vertical P! CHAPTER 2 1952 Guide 76. Scale Trap -Q-. 80.6 Evaporator Pressure Regulating, Throt tling Type (Evapo rator Side)' ' ' 77.' Spray Pond 80.7 Hand Expansion 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 jfT 0 -f- 80.4 Evaporator Pressure Regulating, Snap Action 80.5 Evaporator Pressure .Regulating, Thermo static Throttling Type --(s>t -<5^ 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 6" 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 from1 Part V, Fourth Edition, of the Engineering Standards of the Heat ing] Piping and Air Conditioning Contractors National- AssociationJ ' Class F--Fire-protection D--Dangerous materials S-^Safe Materials and, when required . P--Protective materials . V--Extra valuable materials Colob Red Yellow or Orange Green (or the achromatic black, gray or aluminum) . colors, white, Bright blue . Deep purple -, Fig. 1. Main Classification by Colob . . ' See-Scheme for Identification of Piping Systems, A13-I928, 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 - 1 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. ,q. = U. - U, + w . For a constant pressure process ' (1) -: iq = Hi -- Hi (2) where iq> = energy added between points 1 and 2. U = internal energy of system. w = work done by syBtem. . . H = enthalpy of system. . ... .. ` Subscripts X and 2 refer to sections of the system between which a change takes place. .. . For engineering problems, a more important application of the First Law is its use in cases in winch, in addition to energy, one or more fluids are crossing the boundaries of the syBtem. 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 24 CHAPTER 3 1952 Guide velocity, and energy in the form of enthalpy. Additional, energy may cross the boundaries of the system in the forms of heat or work. The various forms of energy crossing the boundaries between the sections under consideration may be equated by applying the First Law of Thermody namics: --- - PE, -{- KEi 4- Ei 4- iff* -- PEi r KEi 4- Hi 4- iv (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. iff* = 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 VL- -WORK heat- t------- =Vs He Fio. 1. Eneboy 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- iff* = Hi 4- ` (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 + 4- Sh,, . (5) where h = enthalpy of moist air, Btu per pound of dry air, hwi =*- enthalpy.of liquid water, Btu per pound. h-n = enthalpy of solid water, Btu per pound. L = flow rate of liquid water, pounds per hour. . S == flow rate of solid water, pounds per hour. - . G = flow rate of dry air, pounds per hour. Thermodynamics 25 ' Similarly, an equation expressing the conservation of mass may be written thus: .. ; . ; where 23 [<7(I. + W) + L + S] = 23 1^(1 + ^ + L + SJ "in ' out . - " (6) ' .. W = 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 diy 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 and barometric pressure. ........... - Relative humidity and degree of saturation are related according to the identity: . [. - 0 (7) where . * = relative humidity, expressed as a decimal. It = degree of saturation, expressed as. a decimal. Pm = observed (or barometric) pressure of the moist air. .. Pm = saturation pressure of pure water at the prevailing temperature, expressed in the same units as P. / = a dimension]esa factor which may be regarded as accounting for influences arising when air and water are intermixed. Magnitudes of / have been reported by Goff and Gratch1 and by Goff* Table 1 gives values of /, for a limited range of conditions. 26 CHAPTER 3 1952 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 A,, TP,,. 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 . hi + (W* -- W\)h,* = h* . (8) where * indicates condition at thermodynamic wet-bulb temperature. Table 1. Magnitudes op /. fob the Range 0 to i25 F . (Standard Barometric Pressure, 29.921 in. Hg) Temp. F /s Temp. F A 0 1.0048 10 1.0046 20 1:0046 30 . 1.0045 , 40 . 1.0044 50 1.0044 60 . 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 eouree1 gives / to seven significant figures over the temperature range 208 F to + 202 F and over the pressure range 20 to 36 in. Hg. ` The temperature corresponding to h* for given values of hi and TP, 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; (6) conduction of heat along the stem of the thermometer; and (c) impact of the air on the wick or bulb of the thermometer. Arnold1 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 ho 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- tomic gases at low pressures follows these equations closely enough 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 rioted 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 1952 Guide gas is heated' or cooled at constant pressure, the volume vanes as the absolute temperature T. Stated mathematically, . .. --P = constant (volume constant) (10) y ' '' . ' ' -- = 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 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, .- Vm = F. = v. Tm = To = T- . V (13) . (14)' Pm -- pi + P mmh - nuh* + (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: ,, ,, = = + (17)n'RT n.)BT . Vt p. V- P, where Vt = total volume, cubic feet. n = number of mols of dry air. . . . Thermodynamics 29 nw = number of.mols of water vapor. . -. , . R = universal gas constant, 1545 foot-pounds per (Fahrenheit degree) (mol).. ; p = 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 _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 preshire of the mixture. A similar expression is obtained for the diy 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 V> = + n. (19) 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, '- - :- . ' . Pt. ' . The humidity ratio W may be obtained from.Equation 17: W 18.016 p, 0 622 P 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 = h. + (22) h = enthalpy, Btu per pound of dry air. . In relating the. enthalpy to the state of the moist air, the fact that in all applications only differences in enthalpy are involved, allows the arbitrary selection of a datum or zero enthalpy point. Accordingly, from perfect gas relationships, it is possible to write for any temperature of (, Fahrenheit greater than OF _ ____ 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. Tables 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 1952 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. t 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 eucK'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 ' and Ventilating Engineers and the Towne Scientific School of the University of Pennsylvania. These properties are published herein as Table 2, and are taken from a research report by Goff and Gratch.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. . ((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. .. , IF, -- 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 in the case of Table 2). At given values of temperature and pressure, the humidity ratio W can have any value from zero to IF.. ' t>* = specific volume, of dry air, cubic feet per pound. ... . . ; iiu;= v,the,,difference between the volume, of moist -air at saturation, per pound of dry air, antrthe specific volume of the dry air itself, cubic feet per pound of dry air. ' .. ' ! tv = specific volume Of moist air at saturation per pound of dry air, cubic feet per . pound of dry air. , '- A.= specific enthalpy of dry air, Btu per pound of dry air. The specific enthalpy of dry air has been assigned the value zero at 0 F, standard atmospheric pressure. The energy unit Btu is related to the foot-pound by definition, as follows: 1 Btu = 778.3ft-lb. .. . . ... , A,, = h, -- A., the difference between the enthalpy of moist air at saturation, per pound of dry air, and the specific enthalpy of the dry air itself, Btu per pound of dry air. . A. = enthalpy of moist air at saturation per pound of dry air, Btu per pound of dry air. ... .. ' 8, ='specific entropy jof,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. . iu = 8. -- s., 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 ary air) (Fahrenheit degree). 8. = entropy of moist air at saturation per pound of dry air, Btu per (pound of dry air) (Fahrenheit degree). - . . . A. = 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 pressure, Btu per (pound of water) (Fahrenheit degree). The specific entropy of ^liquid water has been assigned the value zero at 32 F, saturation pressure (0.088586 *psia). , '' 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 IF, 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 saturation pressure listed in Table 2 have been computed from the formulas of Goff and Gratch. .. THERMODYNAMIC PROPERTIES OF WATER AT SATURATION Since water vapor at low pressures acts almost as a perfect gas, the enthalpy of water vapor should also be a function only of the temperature within these limits. Therefore, the enthalpy of the water vapor may be expressed as being approximately equal to file enthalpy of saturated vapor at the dry-bulb temperature of the mixture. Substituting these values in Equation 22, the enthalpy of the mixture becomes \ - A = 0.24 I + Wht (25) where he is the value of the enthalpy of saturated vapor at the temperature f, 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 Obviously the degree of saturation p can have any value from zero (dry an-) to unity (moist air at saturation). The degree of saturation, is con- I. CHAPTER 3 ' 1952 Guide -J jl \ Table 2. Thebmodynamic Pbopebties op Moist Am* (Standard Atmospheric Pressure, 29.921 in. Ho) Fahb. Temp. 1(F) -160 -155 -150 -145 -140 -135 -130 -125 -120 -115 -no -105 -100 -95 -90 -85 -80 -75 -70 -65 -60 -55 -50 -48 -46 -44 -42 -40 -38 -30 -34 -32 Humidity Ratio W X 10* 0.0002120 0.0003869 0.0006932 0.001219 0.002109 0.003586 0.006000 0.009887 ' 0.01606 0.02571 0.04063 0.06340 0.09772 0.1489 0.2242 0.3342 0.4930 0.7196 1.040 1.491 2.116 2.982 4.163 4.747 5.406 6.149 6.985 7.926 8.980 10.16 11.49 12.98 1 . Volume cu pt/lb dby AIB Enthalpy Btu/lb dby aib V* Vaa v A* Aaa 4. 7.520 7.647 7.775 7.902 0.000 0.000 0.000 0.000 8.029 8.156 8.283 8.411 0.000 0.000 0.000 0.000 8.537 8.664 8.792 8.919 0.000 0.000 0.000 0.000 9.046 9.173 9.300 9.426 0.000 - 0.000 0.000 0.000 9.553 9.680 9.806 9.932 10.059 10.186 10.313 10.364 0.000 0.000 0.000 0.000 o.ooo. 0.000 0.001. 0.001 10.414 10.465 10.516 10.566 0.001 0.001 0.001 0.001 10.617 . 10.668 10.718 10.769 0.002 0.002 0.002 0.002 7.620 7.647 7.775 7.902 -38.504 -37.296 -36.088 -34.881 8.029 .8.156 8.283 8.411 -33.674 -32.468 -31.262 -30.057 0.000 0.000 0.000 0.000 . 0.000 ' 0.000 0.000 0.000 . -88.504 -37.296 -36.088 -34.881 -33:674 -32.468 -31.202 -30.057 8.537 8.664 8.792 8.919 -28.852 -27.648 -26.444 -25.240 0.000 0.000 0.000 0.001 -28; 852 -27.648 --26.444 -25.239 9.046 9.173 0.300 9.426 -24.037 -22.835 -21.631 -20.428 0.001. 0.002 0.002 0.003 -24.036 -22.833 -21.629 -20.425 9.553 6.680 6.806 9.932 -19.225 -18.022 -16.820 t15.617 0.005 0.007 0.011 0.015 -19.220 -18.015 -16.809 -15.602 10.059 10.186 10.314 10.365 -14.416 -13.214 -12,012 -11.532 0.022 0.031 0.043 0.046 -14.394 -13.183 -11.969 -11.483 10.415 10.466 10.517 10.567 -11.051 -10.571 -10.090 -9.609 0.056 0.064 0.073 ' 0.083 -10.965 -10.507 -10.017 -9.526 10.619 10.070 10.720 10.771 -9.129 -8.648 -8.108 -7.687 0.094 0.100 ' 0.121 0.136 -9.035 -8.542 -8.047 -7.551 Entbopy . Btu peb(*F) (lb dby aib) . 4a ff&a ' tfa Condensed Wateb Enthalpy Btu/Lb Aw Entropy Btu/(Lb) rF) w ' Vap. Press. In. Hg a X 10* . Fahb. Temp. t(F) -0.10300 -0.09901 -0.09508 -0.09121 0.00000 0.00000 0.00000 0.00000 -0.10300 -0.09901 -0.09508 -0.00121 -222:00 -220.40 -218.77 -217.12 -0.08740 -0.08365 -0.07997 -0.07634 0.00000 -0.08740 , 0.00000 -0.08365 0.00000 -0.07997 0.00000 . -0.07634 -215.44 -213.75 -212.03 -210.28 -0,07277 -0.06924 -0.06577 -0.06234 0.00000 0.00000 0.00000 0.00000 -0.07277 -0.06924 ' -0.06577 -0.00234 -208 i 62 -200.73 -204.62 -203.08 -0.05897 -0.05566 -0.05237 , -0.04913 0.00000 0.00000 0.00001 0.00001 -0.05897 -0.05565 -0.05236 -0.04912 -201.23 -199.35 -197.44 -195.61 -0.04595 -0.04280 -0.03960 -0.03663 0.00001 0.00002 0.00003 0.00005 -0.04594 -0.04278 -0.03966 -0.03658 -193.56 -101.57 -189.66 -187.53 -0.03360 -0.03061 -0.02766 -0.02646 0.00006 0.00009 0.00012 .0.00013 -0.03354 -0.03052 -0.02754 -0.02636 -185.47 -183.39 -181.29 -180.44 -0.02532 -0.02416 -0.02301 -0.02186 ' 0.00014 0.00016 0.00019 0.00021 -0.02518 -0.02400 -0.02282 -0.02165 % -179.59 -178.73 -177.87 -177.01 -0.02072 -0,01958 -0.01845 -0.01733 0.00024 0,00026 0.00030 0.00034 -0.02048 -0.01932 -0.01815 -0.01699 -170.14 -175.27 -174.40 --173.62 -0.4907" -0.4853 -0.4800 -0.4747 0.0001009> 0.0001842' 0.0003301 0.0005807 -0.4695 ' 0.001004 --0.4642 0.001707 -0.4500 0.002858 -0.4538 0.004710 -0.4485 -0.4433 -0.4381 -0.4329 0.007653 0.01226 0.01939 0.03026 , -0.4277 -0.4225 -0.4173 -0.4121 0.04666 0.07111 0.1071 0.1697 -0.4069 -0.4017 -0.3966 -0.3913 0.2356 0.3441 0.4976 0.7130 -0.3861 -0.3810 -0.3758 -0.3738 1.0127 1.4258 1.9910 2.2702 .- -0.3717 -0.3696 -0.3670 -0.3655 2.5854 2.9408 3.3408 3.7006 -0.3634 -0.3614 -0.3593 -0.3573 4.2658 4.8626 5.4980 6.2093 ' -160 -155 -150 -146 ' -140 -135 -130 -126 -120 -116 -no -106 -100 -96 -90 -85 . . -80 -75 -70 -65 . -60 -55 -60 -48 - -46 -44 -42 -40 -38 -36 -34 -32 - * Compiled by John A. GoS and S. Gratch, to Table 2. (Continued)Thermodynamic Pbopebties of Moist Air. (Standard Atmospheric Pbessube, 29.921 in. Ho) Fahb. Temp. t(F) Humidity Ratio WtxlO* Volume cu pt/lb dby aib -30 -28 -26 -24 -22 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -30 -9 -8 -7 -8 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 1.464 1.649 1.856 2.087 2.344 2.630 2.785 2.948 3.120 3.301 3.491 3.692 3.903 4.125 4.359 4.606 4.866 5.137 5.423 5.724 6.040 6.371 6.720 7.085 7.469 7.872 8.295 8.739 9.204 9.692 10.20 10.74 10.820 10.870 10.921 10.972 11.022 11.073 11.098 11.124 11.149 .11.174 11.200 11.225 11.250 11.275 11.301 11.326 11.351 11.376 11.401 11.427 11.452 11.477 11.502 11.528 11.553 11.678 11.604 11.629 11.654 11.679 11.705 11.730 0.002 0.003 0.003 0.004 0.004 0.005 0.005 0.005 0.006 0.006 0.006 0.007 0.007 0.008 0.008 0.008 0.008 0.009 0.010 0.010 0.011 0.012 0.013 0.013 0.014 0.015 0.016 0.016 0.017 0.018 0.019 0.020 10.822 10.873 10.924 10.976 11.026 11.078 11.103 11.129 11.165 11.180 11.206 11.232 11.257 11.283 11.309 11.334 11.359 11.385 11.411 11.437 11.463 11.489 11.515 11.541 11.567 11.693 11.619 11.646 11.671 11.697 11.724 11.750 Compiled by John A. Goff and 8..Gratch. - Enthalpy Btu/lb dby aib ' _ Entbopy Btu peb (F)' (lb dby aib) -7.207 -0.720 -6.240 -5.765 -5.285 -4.804 -4.564 -4.324 -4.083 -3.843 -3.603 -3.303 -3.123 -2:882 -2.642 -2.402 -2.162 -1.922 -1.681 -1,441 -1.201 -0.901 -0,721 -0.480 -0.240 0.000 0.240 0.480 0.721 0.961 1.201 1.441 0.154 0.173 0.196 0.216 . 0.246 0.277 0.293 0.310 0.328 0.348 0.368 0.389 0/412 0.436 0.461 0.487 0.514 0.543 0.574 0.606 0.639 0.675 0.712 0.751 0.792 0.835 0.880 0.928 0;977 1.030 1.085 1.142 -7.053 -6.553 -0.050 -5.546 -5.039 --4.527 --4.271 -4.014 -3.755 -3.495 -3.235 -2.974 2.711 -2.446 -2.181 -1.915 -1.648 -1.379 -1.107 -0.835 -0.562 -0.286 -0.009 0.271 0.562 0.835 1.120 1.408 1.698 1.991 2.236 2.583 -0.01621 -0.01509 -0.01398 -0.01287 -0.01177 -0.01067 -0.01012 -0.00958 -0.00904 -0.00850 -0.00790 -0.00743 -0.00689 -0.00630 -0.00582 -0.00529 -0.00475 -0.00422 -0.00369 -0.00310 -0.00263 -0.00210 -0.00167 -0.00105 -0.00052 0.00000 0.00052 0,00104 0.00156 0.00208 0.00260 0.00312 0.00038 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 0.00135 0.00142 0.00149 0.00157 0.00165 0.00174 0.00183 0.00192 0.00202 0.00212 0.00223 0.00234 0.00246 0.00258 -0.01683 -0.01460 -0.01350 --0.01233 -0.01116 -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 0.00310 0.00379 0.00442 0.00506 0,00570 Condensed Wateb Enthalpy Btu/Lb Aw -172.64 -171.75 -170.86 -169.97 ^-169.07 -168.17 -167.72 -167.26 -160.81 -166.35 -165.90 -165.44 -164.98 -164.52 -164.06 -163.60 -163.14 -162.67 -162.21 -161.74 -161.28 -160.81 -160.34 -159.87 -159.40 -158.93 -158.46 -157.99 -157.52 -157.04 -156.57 -166.09 -0.3552 -0.3531 -0.3511 -0.3490 -0.3460 -0.3449 -0.3439 -0.3428 -0.3418 -0.3408 -0.3398 -0.3387 -0.3377 -0.3367 -0.3367 -0.3346 -0.3336 -0.3326 -0.3310 -0.3305 -0.3295 -0.3285 -0.3275 -0.3284 -0.3254 -0.3244 -0.3234 -0.3223 -0.3213 -0.3203 -0.3193 -0.3182 Vap. Press In Hg p x 10* 0.70046 0.78928 0.88838 0.99885 1.1219 1.2587 1.3327 1.4107 1.4929 1.5795 1.6706 1.7666 1.8077 1.9740 2.0859 2,2035 2.3273 2.4573 2.5940. 2.7377 2.8886 3.0472 3.2137 3.3885 O.i040 3.9666 4.1785 4.4007 4.6337 4.8779 6.1339 Fahb. Temp. <(F) -30 -28 -20 -24 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 --6 -5 -4 -3 -2 -1 0 1 2 '3 4 6 6 CO CO Thermodynamics CHAPTER 3 - Fahb. Temp. , ((F) Table 2. Humidity Ratio W.x 10* MThermodynamic.Properties of oist Air* (Standabd Atmospheric Pressure, 29.921 in. Ho) (Continued) --------------- ---------------------------------------------- . , Volume CU FI/lb DBY AIB , Enthalpy ....... Btu/lb dry aib ' . Entbo'py . , . Bru peb (F) (lb DBY aib) Condensed Water h. h.Da tfea t>a ' 5m . . 8m . fta Enthalpy , - Btu/Lb Entropy Btu^Lb) Vap. Press In. Hg Aw'. ' w: ' Pa X 10* 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 26 26 . 27 28 29 30 g- 32* 33 .34 * 36 36 37 1.130 1.189 1.251 1.316 1.383 . 1.464 1.528 1.606 1.687 1.772 1.861 1.953 2.061 2.162 2.258 2.369 2.485 2.606 2.733 2.865 8.003 3.147 3.297 3.454 3.617 3.788 3.788 3.944 4.107 4.275 4.450 4.631 11.756 11.781 11.806 11.831 0.021 0.022 0.024 0.025. 11.777 11.803 11.830 11.856 11.857 11.882 11.907 11.933 0.026 0.028 0.029 . 0.030 11.883 11.910 11.936 11.963 11.958 11.983 12.009 12.034 0.032 0.034 0.035 0.038 11.990 12.017 12.044 12.072 12.059 12.084 12.110 12.135 0.040 0.042 0.044 0.046 12.099 12.126 12.154 12.181 12.160 12.186 12.211 12.236 0.046 0.051 0.054 0.057 12.209 12.237 12.265 12.293 12.262 12.287 12.312 12.338 0.059 0.062 0.065 0.068 12.321 12.349 12.377 12.406 12.363 12.388 12.388 12.413 12.438 12.464 12.489 12.514 0.071 0.075 0.075 0.079 . 12.434 12.463 12.463 12.492 0.082 0.085 0.089 0.093. ' 12.520 12.546 12.678 12.607 1.681 1.922 2.162' 2.402 2.642 2.882 3.123 3.363 3.603 3.843 4.083 4.324 4.564 4.804 5.044 5.284 5.525 5.765 6.005 ' 6.245 6.485' 6.726 6.966 7.206 7.446 7.686 7.686 ,7.927 8.167 . 8.407 8.647 8.887 ' 1.202' 1.266 1.332 1.401 1.474 1.550 1.630 1.713 1.800 1.892 1.988 2.088 2.192 2.302 2.416 2.536 2.661 2.792 2.929 3.072 3.221 3.377 8.640 3.709 3.887 4.072 4.072'. 4.242' 4.418 4.601 4.791 4.987 2.883 3.188 3.494 3.803 4.116 4.432 4.763 5.076 5.403 5.735 6.071 6.412 6.758 7.106 7.460 7.820 8.186 8.857. 8.934 9.317 9.706 10;103 10.506: 10:915 11.333 11.758, 11.758 12.169 12.585 13.008 -13.438 13.874 0.00364 0.00415 0.00467 0.00518 o!b0569 0.00620' 0.00871 0.00721 0ib0772 0.00822 0.00873 0.00923 0.00973 ' 0.01023, 0.01073 0.0(123 001173 0.01223 0.01273 0.01322 0.01872 0.01421 0.01470 0.01519 0.01568 0.01617 0.01617 0.01666 0.01716 0.01764 0.01812 0-.01861 0.00271 0.00285 0.00299 0.00314 0.00635 0.00700 0,00766 0.00832 0.00330 0.00346 0.00363 0.00380 0.00399 0.00418 0.00438 0.00459 0.00899 0.00966 0.01034 ; 0.01101 ' 0.01171 0.01240 0.01311 0.01382 0.00481 0.00504 0.00528 0.00553 0.01454 0.01527 0.01601 0.01676 0.00579 0.00607 0.00635 0.00665 0.01752 0.01830 0.01908 0.01887 0.00696 0.00728 0.00761 0.00796 0.02068 -0.02149 0.02231 0.02316 0.00832 0.00870. 0.00870 0.00904 0.02400 0.02487 ' 0.02487 0.02570 0.00940 0.00977 0.01016 0.01058. 0.02655 0.02741 0.02828 0.02917' -165.61 -155.13 -154.65 -154.17 --153.69 -163.21 -162.73 -162.24 -151.76 -151.27 -150.78 -150.29 -149.80 -149.31 -148.82 -148.33 -147.84 -147.34 -146.85 -146.35 ^--145.85 --145.36 -144.86 -144.36 -148.86 -143.36 0.04\ 1.05' 2.06 3.06 4.07 5.07 -0.3172 -0.3162 -0.3152 -0.3141 -6.3131 -0.3121 -0.3111 -0.3100 --6.3090 -0.3080 -0.3070 0.3059 -0.3049 -0.3039 -0.3029 -0.3018 -0.3008 -0.2998 -0.2888 -0.2977 -0.2967 -0.2957 -0.2947 -0.2636 -0.2926 -0.2816 O.QOOO 0.0020 6.0041 0.0061 0.0081 0.0102 6.4022 5.6832 ' 5.9776 6.2858 6.6085 -6.9462 7.2997 7.6696 8.0565 8.4612 8.8843 9.3267 9.7889 10.272 10.777 11.305 11.856 12.431 13.032 13.659 14.313 14.666 . 15.709 16.452 17.227 18.035 18.037 1J.778 19.646 20.342 21.166 22.020 Compiled by John A. Goff and 8. Gratoh. , ' . ' * Extrapolated to represent znetaatable equilibriupi with undercooled liquid. Fahb' Temp 1(F) 7 8 9 10. . 11 12 13 14 16 16 17 18 19 20 21 22 23 24 25 26 27 28 26 SO 31 32 32* 33 34 85 36 37 ss . 1952 Guide | | Thermodynamics Table 2. Thermodynamic Properties of Moist Air* (Standard Atmospheric Pressure, 29.921 in. Ho) (Continued) Fahb. Temp. ((F). Humidity Ratio W% x 10* . Volume cu pt/lb dry aib . Vm Pa Enthalpy Btu/lb dry air fcu h. 38 89 40 41 42 43 44 45 46 47 48 49 60 51 52 53 54 55 56 57 58 56 60 61 .... 62 63 64 65 66 87 68 69 ' 4.818 6.012 5.213 5.421 5.638 5.860 6.061 6.331 6.`67k 6.835 7.100 7.374 7.858 7.952 8.266 8.569 8.894 6.229 9.576 9.934 10.30 10.66 11.08 11.49 .11.61 12.35 12.80 13.26 13.74' 14.24' 14.76 15.28 12.540 12.665 12.660 12.616 12.641 12.666 12.691 12.717 12:742 12:767 12.792 12.818 12.843 12.868 12.894 12.919 12.944 12:970 12.665 13.020 13.045 13.071 13.096 * 13.121 13.147 13.172 13.167 13.222 13.247 13.273 13.298 13.323 6.097 0.101 0.105 0.109 0.114 0.119 0.124 0.129 6.134 0.140 0.146 0.151 0.158 0.164. 0.170 0.178 6.185 0.162 0.200 0.208 0.216 0.224 0.233 0.242 0.251 0.261 0.271 0.282 0.292 0.303 0.315 0.327 12.637 12.666 12.665 12.725 9.128 9.368 6.608 6.848 12.755 12.785 12.815 12.846 10.088 10.326 10.569 10.809 12.876 12.607 12.938 12.969 11.049 11.289 11.530 11.770 13.001 13.032 13.064 13.097 . 12.010 12.250 12.491 12.731 13.129 13.162 13.165 13.228 12.971 13.211 13.452 13:692 . 13:261 13.295 13.329 14.363 13:932 14,172 14.413 14.653 13.368 13.433 13.468 13.504 14.893 15.134 15.374 15.614 13.539 13.576 .13.613 ' 13:650 15.855 16.095 16.335 16.576 5.191 5.403 6.662 5.849 14.319 14.771 15.230 15.697 6.084 6.328 6.580 6.841 16.172 16.657 17.149 17.650 7.112 . 7.391 7.681 7.981 18.161 18.680 19.211 19.751 8.291 8.612 8.945 9.289 20.301 20.862 21.436 22.020. 9.644 10.01 10.39 10.79 22.615 23.22 23.84* 24.48. 11.19 11:61 12.05' 12.50. 26.12. 25.7826.46 27.15- 12.06 13.44 13.94 14.45 27.85 28.67 29.31 30.06 14.98 15.63 16.09. 16.67 . 30.83 31.62: 32.42. 33.25 * Compiled by John A. Goff and.8. Gratoh. Entropy Btu per (eF) (lb dry air) Saf.. a 0.01909 0.01957 0.02005 0.02053 0.02101 0.02149 0.02197 0.02245 6.02293 0.02340 0.02387 0.02434 0.02481 0.02528 0.02575 0.02622 0.02669 0.02716 0.02762 0.02809 0.02855 0.02902 0.02948 0.02994 0.03040 0.03086 0.03132 0.03177 0.03223 0.03269 0.03314 0.03360 0.01097 0.01139 0.01183 0.01228 6.01275 0.01323 0.01373 0.01425 0.01478 0.01534 0.01591 0.01650 6.01711 0.01774 0.01839 0.01906 0.01976 0.02047 0.02121 0.02197 0.02276 0.02357 0.02441 0.02527 0.02616 0.02708 0.02803 0.02901 0.03002 0.03106 . 0.03213 ; Q, 03323- 0.03006 0.03096 0.03188 0.03281 0.03376' 0.03472 0.03570 0.03670 0.03771 0.03874 0.03978 0.04084 0.04192 0.04302 6.04414 0.04528 0.04645 0.04763 0.04883 0.05000 0.05J31 0.05259 0.05389 0.05521 0.06656 0.05794 0.05935 0.06078 0.06225 0.06375 0.06527 0.06683 Condensed Water Enthalpy Btu/Lt> Aw Entropy Btu/(Lb) (F) ' 9w Vap. Press In. Hg Pa . 6.08 7.08 8.09 9.09 10.09 11.10 12.10 13.10 14.10 15.11 16.11 17.11. 18.11 19.11 20.11 21.12 ' 22.12 23.12 24.12 25.12 26.12 27.12 28.12 29.12 30.12 31.12 32.12 . 33.11 34! 11 35.11 36.11 37.11 0.0122 0.0142 0.0162 0.0182 6.0202 0.0222 0.0242 0.0262 0.22904 0.23819 0.24707 0.25748 6.20703 ` 0.27813 0.28899 0.30023 0.0282 0.0302 0.0321 0.0341 0.31185 0.32386 0.33629 0.84913 0.0361 0.0381 0.0400 0.0420 0.36240 0.37011 0.39028 0.40492 0.0439 0.0459 0.0478 0.0497 ' 0.42004 0.43565 0.45176 0.46840 0.0517 o0..0o5e3e6s 0:0574 0.0584 0.0613 0.0632 . 0.0651 ' 0.48558 0.50330 0.52159 0.54047 6.55994 0.58002 0.60073 0.62209 6.0070 0.0689 0.0708 0.0727 0.64411 .0.66681 0.69010 ' ` 0.71430 Fahb. Temp. ((F) 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 64 55 56 57, 58 59 ,60 61 62 63 64 65 66. 07 68 69 - \ Table 2. Thermodynamic Properties of Moist Air11 (Standard Atmospheric Pressure, 29.921 in. Hq) (Continued) t Fahr. ` Temp. t(F) Humidity Ratio W, x 10* Volume cu ft/lb dry air to toe to 74 79 84 89 94 99 - 104 1.819 2.156 2.555 3.017 3.555 4.182 4. Alfa 4.911 13.348 13.373 13.398 13.424 13.449 13.474 13.499 13.525 13.550 13.575 13.601 13.626 13.651 13.676 13.702 13.727 13.75213.777 13.803 13.828 13.853 13.879 13.904 13.929 13.954 13.980 14.005 14.030 14.056 14.081 14.106 14.131 14.157 14.182 14.207 0.839 0.351 0.864 0.377 0.392 0.407 0.422 0.437 0.463 0.470 0.486 0.504 0.623 0.542 0.560 0.581 0.602 0.624 0.646 0.668 0.692 0.718 0.741 0.768 0.795 0.822 0.851 0.881 0.911 0.942 0.075 1.009. 1.043 1.079 1.117 13.687 13.724 13.762 13.801 13.841 13.881 13.921 13.962 14.003 14.045 14.087 14.130 14.174 14.218 14.262 14.308 14.354 14.401 14.448 14.496 14.645 14.595 14.645 14.697 14.749 14.802 14.856 14.911 14.967 15.023 15.081 15.140 15.200 15.261 15.324 a Compiled by John A. Goff and s/Gratch. . Enthalpy Btu/lb dry air Am h. 16.816 17.056 17.297 17.537 17.778 17.27 17.89 18.53 19.20 19.68 18.018 18.259 18.499 18.740 18.980 20.59 21.31 22.07 22.84 23.64 19.221 19.461 19.702 19.942 20.183 24.47 25.32 26.20 27.10 28.04 20.423 20.663 20.904 21.144 21.385 29.01 30.00 31.03 32.09 33.18 21.625 21.865 22.106 22.346 22.687 34.31 35.47 36.67 37.90 39.18 22.827 23.068 23.308 23.548 23:789 40.49 41.85 43.24 44.68 46.17 24.029 47.70 24.27Q 49.28 24.610 50.01 24.751 52.59' 24.991 54.32 34.09 34.95 35.83 36.74 37.66 38.61 39.57 40.57 41.58 42.62 43.69 44.78 45.90 47.04 48.22 49.43 60.66 51.93 53.23 54.56 55.93 57.33 58.78 60.25 61.77 63.32 64.92 66.55 68.23 69.96 71.73 73.55 75.42 77.34 79;31 Entropy Btu per (*F) (lb dry air) to toa a 6.03405 0.03450 0.03405 0.03540 0.03585 0.03437 0.03554 0.03675 0.03800 0.03928 0.03630 0.03675 0.03720 0.03765 0.03810 0.04060 0.04197 0.04337 0.04482 0.04631 0.03854 0.03899 0.03943 0.03987 0.04031 0.04784 0.04942 0.05105 0.05273 0.05446 0.04075 0.04119 0.04163 0.04207 0.04261 0.05624 0.05807 0.05995 0.06189 0.06389 0.04295' 0.04339 0.04382 0.04426 . 0.04469 6.04513 0.04556 0.04600 0.04643 0.04686 0.06596 0.06807 0.07025 0.07249 0.07480 0.07718' 0.07963 0.08215 0.08474 0.08741 0.04729 0.09016 0.04772 . 0.09299 0.04815 ' 0.09691' 0.04858 0.09891' 0.04900 - 0.1020 0.06842 0.07004 0.07170 0.07340 0.07513 0.07660 0.07872 0.08057 0.08247 0.08441 0.08638 0.08841 0.09048 0.09260 0.09477 0.09669 0.06926 0.10158 0.10366 0.10640 0.10890 0.11146 0.11407 0.11675 0.11949 0.12231 0.12519 0.12815 0.13117 0.13427 0.13745 0.14071 0.14406 0.14746 0.1510 Condensed . Water Enthalpy Btu/Lo Aw Entropy Btu4P> w, Vap. Press In. Hg P ' Fabb. Temp. ((F) 38.11 se.ii 40.11 41.11 42.10 43.10 44.10 45.10 46.10 47.10 48.10 49.09 60.09 51.09 62.09 53.09 54.08 56.u8 56.08 57.08 58.08 59.07 60.07 61.07 62.07 63.07 64.06 65.06 66.06 67.06 68.06 69.05 70.05 71.05 72.05 0.0746 0.0765 0.0784 0.0803 0.0821 0.0840 0.0850 0.0877 0.0806 0.0914 0.0933 0.0052 0.0970 0.0989 0.1007 0.1025 0.1043 0.1062 0.1080 0.1098 0.1116 0.1135 0.1153 0.1171 0.1188 0.1206 0.1224 0.1242 0.1260 0.1278 0.1296' 0.1314 0.1332 0.1350 0.1307 0.73915 0.76475 0.79112 0.81828 0.84624 . 0.87504 0.90470 0.93523 0.06665 0.99899 1.0323 I.0665 1.1017 1.1379 1.1762 1.2135 1.2620 1.2034 1.3301 1.3770 1.4219 1.4671 1.5135 1.5612 1.6102 r.6606 1.7123 1.7654 1.8199 1.8759 1.9333 1.9923 2.0528 2.1149 2.1786 70 71 - 72 73 74 75 70 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 . 96 97 98 99 100. 101 102 103 104 . .1952 G u id e 'E R 3 OS. MfMW OSSS*. ' S Therm odynam ics . Table 2. Thermodynamic Properties of Moist Air* (Standard Atmospheric Pressure, 29.921 in. Hg) (Continued) 'Fahr. Temp. t(F) ,Humidity Ratio . W x 10 Volumb cu ft/lb DRY XlB . to toa fa Enthalpy Btu/lb dry air Ac Am Aa 105 106 107 108 109 no 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 - 135 136 137 139 0.6070 0.5234 0.6404 0.5578 0.5758 14.232 14.258 14.283 14.808 14.333 1.155 1.194 1.235 1.278 1.321 0.5944 0.6135 0.6333 0.6536 0.6746 14.359 14.384 14.409. 14.436 14.460 1.365 1.412 1.460 1.509 1.560 0.6962 14."485 0.7185 14.510 0.7415 1.4.636 0.7652 14.561 0.7897 14.586 1.613 1.668 1.723 1.782 1.842 0.8149 0.8410 0.8678 sO.8955 0.9242 14.611 14.637 14.662 14.687 14.712 1.905 1.968 2.034 2.103 2.174 0.9537 . 0.9841 1.016 1.048 ' 1.082 i.116 1.152 1.169 1.227 1.267 14.738 14.763 14.788 14.813 14.839 14.864 14.889 14.915 14.940 14.965 ' 2.247 2.323 2.401 2.482 2.565 2.652 2.742 2.834 2.930 3.029 '1.308 - 1.350 ' 1.393 1.439 1.485 14.990 16.016 15.041 15.066 15.091 3.132 3.237 3.348 3.462 3.580 15.387 15.452 15.518 15.586 15.654 15.724 15.796 15.869 15.944 16.020 16.098 10.178 16.259 16.343 16.428 16.516 16.605 16.696 16.790 16.886 16.985 17.086 17.189 17.295 17.404 17.518 17.631 17.749 17.870 17.994 18.122 18.253 18.389 18.528 18.671 * Compiled by John'A. Goff and S. Gratch. 25.232 25.472 26.713 25.953 26.194 56.11 57.95 59.85 61.80 63.82 26.434 26.675 26.915 27.156 27.397 65.91 68.05 70.27 72.55 74.91 27.037 , 27.878 28.119 28.359 28.600 77.34 79.85 82.43 85.10 87.86 28.841 29.062 29.322 29.563 29.804 90.70 93.64 96.66 99.79 103.0 30.044 30.285 30.526 30.766 31.007 106.4 109.8 113.4 117.0 120.8 , 31.248 31.489 31.729 31.970 32.211 124.7 128.8 133.0 137.3 141.8 32.452 82.692 32.933 33.174 83.414 146.4 151.2" 156.1 161.2 166.5 . 81.34 83.42 85.56 87.76 60.03 92.34 ' 94.72 .97.18 99.71 .102.31 104.98 107.73 110.55 113.46 116.46 119.54 122.72 125.98 129.35 132.8 136.4 140.1 143.9 147.8 151.8 155.9 100.3 164.7 169.3 174.0 178.9 -183.9 189.0 194.4 199.9 Entropy Btu per (F) (lb dry air) to (aa to 0.04943 0.04985 0.05028 0.05070 0.05113 0.05155 0.05197 0.05239 0.05281 0.05323 0.1052 0.1085 0.1118 0.1163 0.1189 0.1226 0.1264 0.1302 0.1342 0.1384 0.05365 0.05407 0.05449 0.05490 0.05532 0.1426 0.1470 0.1515 0.1562 0.1610 0.05573 0.05615 0.05656 0.05698 0.05739 0.1659 0.1710 0.1763 0.1817 0.1872 0.05780 0.05821 0.05862 0.05903 0.05944 0.1930 0.1989 - 0.2050 0.2113 0.2178 0.05986 0.06026 0,06067 0.06108 0.06148 ' 0.2246 0.2314 0.2386 0.2450 0.2536 0.06189 0.06229 0.06270 0.06310 0.06350 0.2614 0.2695 0.2778 0.2865 0.2954 0.1546 0.1584 0.1621 0.1660 0.1700 0.1742 0.1784 0.1826 0.1870 0.1916 0.1663 0.2011 0.2060 0.2111 0.2163 0.2216 0.2272 0.2326 0.2387 0.2446 0.2508 0.2571 0.2636 0.2703 0.2772 0.2844 0.2617 0.2093 0.3070 0.3151 0.3233 0.3318 0.3406 0.3496 0.3589 Condensed Water Enthalpy Btu/Lo . Aw Entropy B`$f *W Vap. Press In. Hg . Pa Fahr. Temp. t{F) 73.04 74.04 75.04 76.04 77.04 78.03 79.03 80.03 81.03 82.03 83.02 84.02 85.02 86.02 87.02 88.01 89.01 ' 90.01 91.01 92.01 93.01 94.01 95.00 06.00 97.00 98.00 99.00 100.00 101.00 102.00 103.00 104.00 105.00 106.00 107.00 0.1385 0.1403 0.1421 0.1438 i0.1456 0.1472 0.1491 0.1508 0.1525 0.1643 0.1560 0.1577 0.1596 0.1612 0.1629 0.1646 0.1664 0.1681 0.1668 0.1715 0.1732 0.1749 0.1766 0.1783 0.180.0 0.1817 0.1834 0.1851 0.1868 0.1885. 0.1902 0.1618 0.1635 0.1652 0.1969 2.2439 2.3109 2.4502 2.5225 109 2.6726 2.7605 2.8304 2.9123 2.9962 3.0821 3.1701 3.2603 3.3627 3.4474 3.6443 3.6436 3.7452 3.8493 3.9658 4.0646 4.1765 4.29074.4076 4.5272 4.6465 4.7747 4.6028 5.0337' 5.1676 6.3046 6.4446 5.5878 5.7342 114 119 122 123 124 129 130 131 132 133 ' 134 135 - 136 137 138 139 CO -4 r Table 2.'Thermodynamic Properties of Moist Air* (Standard Atmospheric Pressure, 29.921 in. Ho) (Continued) Farr. T BMP. w Humidity Ratio Wt Volume cu ft/lb dry air . Enthalpy Btu/lb dry air Va Vaa v . ha Aaa 140 144 145 148 147 148 140 150 161 152 153 154 165 157 158 169 160 163 164 167 ` 169 170 171 172 173 174 . 0.1534 0.1584 0.1636 0.1689 0.1745 0.1803 0.1862 0.1924 0.1989 0.2055 0.2125 0.2197 0.2271 0.2349 0.2430 0.2514 0.2602 0.2693 0.2788 0.2887 0.2990 0.3098 0.3211 0.3329 0.3452 0.3716 0.3858 0.4007 0.4163 0.4327 0.4500 0.4682 0.4875 0.5078 15.117 15.142 16.167 15.192 15.218 3.702 3.829 3.961 4.098 4.239 18.819 18.971 16.128 16.290 . 19.457 15.243 15.268 15.293 15.319 15.344 4.386 4.539 4.698 4.862 6.033 19.629 19.807 19.991 20.181 20.377 15.369 15.394 15.420 16.445 15.470 5.211 5.396 6.687 5.788 5.996 20.680 20.790 21.007 21.233 21.466 16.496 15.521 15.546 16.571 15.597 6.213 6.439 6.675 6.922 7.178 21.709 21.980 22.221 22.493 22.775 15.622 15.647 15.672 16.698 16.723 7.446 7.727 8.020 8.326 8.648 23.068 23.374 23.692 24.024 24.371 15.748 16.773 16.799 16.824 15.849 8.985 9.339 9.708 10.098 . 10.508 24.733 25.112 25.507 25.922 26.357 15.874 15.900 16.925 1 15.950 15.976 10.938 11.391 s 11.870 12.376. 12.911 26.812 27.291 27.795 28.326 28.886 33.655 33.896 84.136 34.377, 34.618 34.859 35.099 35.340 35.581 35.822 36.063 36.304 36.545 36.785 37.026 37.267 87.508.. 37.749 37.990 38.231 38.472 38.713 38.954 39.195 39.436 39.677 39.918 40.159 40.400 40.641 40.882 41.123 41.364 41.605 41.846 172.0 177.7 183.6 ` 189.7 196.0 202.5 209.3 216.4 223.7 231.3 239.2 247.3 255.9 264.7 273.9 283.5 293.5 303.9 314.7 326.0 337.8 350.1 363.0 376.5 390.5 405.3 420.8 437.0 454.0 471.8 490.6 510.4 531.3 553.3 576.5 205.7 211.6 217.7 224.1 230.6. 237.4 244.4 251.7 259.3 267.1 275.3 283.6 292.4 301.5 310.9-, 320.8 331.0 341.7 352.7 364.2 376.3 388.8 402.0 415.7 429.9 445.0 460.7 447.2 494.4 512.4 531.5 551.5 572.7 594.9 618.3 . Entropy .~ Btu per (F) (lb dry air) (I Fat - a 0,06390 0.06430 0.06470 0.06510 0.06549 0.06589 0.06629 0.06669 0.06708 0.06748 0.06787 0.06827 0.06866 0.06906 0.06945 0.06984 . 0.07023 0.07062 0.07101 0.07140 0.071790.07218 0.07257 0.07296 0.07334 0.07373 0.07411 0.07450 0.07488 0.07527 0.07565 0.07603 0.07641 0.07680 0.07718 0.3047 0.3142 . 0.3241 0.3343 0.3449 0.3559 0.3672 0.3790 0.3912 0.4038 . 0.4169 0.4304 0.4445 0.4591 0.4743 0.4901 0.5066 0.5237. 0.5415 0.5600 0.5793 0.6994 0.6204 0.6423 0.6652 0.6892 0.7142 0.7405 ,0.7680 0.7969 0.8273 0.8592 0.8927 0.9281 0.0654 0.3686 0.3785 0.3888 0.3994 0.4104 0.4218 0.4335 0.4457 0.4583 0.4713 0.4848 0.4987 0.5132 0.5282 0.5438 0.5599 0.5768 0.5943 0.6125 - 0.6314 0.6511 0.6716 0.6930 0.7153 0.7385 0.7629 0.7883 0.8160 0.8429 0.8722 0.9030 0.9352 0.9691 1.0049 1.0426 Condensed Water Enthalpy Btu/Lb Aw BEntturo^py) ' Bw Vap. Press In. Hg . Pa Fabr. Temp. *(F) 107.99 108.99 109.99 110.99 111.99 112.99 113.99 114.99 115.99 116.99 117.99 118.99 119.69 120.69 121.99 122.69 123.99 124.99 125.99 127.00 128.00 129.00 130.00 131.00 132.00 133.00 134.00 135.01 136.01 137.01 138.01 139.01 140.01 141.01 142.02 0.1685 0.2002 0.2018 0.2035 0.2051 0.2068 0.2084 0.2101 0.2117 0.2134 . 6.2150 0.2167 0.2183 0.2200 0.2216 ' 0.2232 0.2248 0.2265 0.2281 0.2297 0.2313 0.2329 0.2345 0.2361 0.2377 0.2393 0.2409 0.2426 0.2441 0.2457 0.2473 0.2489 0.2505 0.2521 0.2537 6.8838 6.0367 6.1930 6.3527 6.5160 6.6828 6.8532 7.0273 7.2051 7.3867 7.5722 7.7616 /.y&su 8.1525 8.d64i 8.5599 8.7701 8.9846 6.2036 .0.4271 9.6556 6.8876 10.125. 10.367 10.614 10.866 11.123 11.385 M.652 11:925 12.203 12.486 12.775 . 13.069 13.369 140 141 142 143 144 145 146 147 148 ` 149 150 151 152 i5a 164 155 156 . 157 i5a 159 160 161 162 163 164 165 166 167 169 . 170 171 172 * Compiled by Joho A. Goff and 8. Gratoh. CO 00 'O CA to o B o. - . Table 2. Thermodynamic Properties of Moist Air* (Standard Atmospheric Pressure, 29.921 in. Ho) (Concluded) sSP ' . Humidity w.Ratio Volume cu ft/lb dry air va Vaa ' . . Enthalpy Btu/lb dry air ' Entropy Btu per (F) (lb dry air) Aa ft Aa . 0a 4aa . 0a 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 ' . 164 165 166 167 168 199 200 0.5262 0.5519 0.5760 0.6016 0.6288 0.6578 0.6887 0.7218 0.7572 0.7963 0.8363 0.8805 0.9283 0.9802 1.037 1.096 1.166 1.241 1.324 1.416 1.519 1.635 1.767 1.617 2.091 2.265 16.001 16.026 16.051 16.076 16.102 13.475 14.074 14.710 15.886 . 16.104 16.127 16.152 16.177 16.203 16.228 16.870 17.689 18.665 19.504 20.513 16.253 16.278 16.304 16.329 16.354 21.601 22.775 24.047 25.427 26.934 16.379 16.405 16.430 16.455 16.480 28.580 30.385 32.375 34.581 37.036 16.508 16.531 16.556 16.581 16.607 16.632 39.785 42.885 46.402 50.426 55.074 60.510- 29.476 30.100 30.761 31.462 32.206 42.087 42.328 42.569 42.810 43.051 32.997 33.841 34.742 35.707 36.741 43.292 43.534 43.775 44.016 44.257 37.854 39.053 40.351 41.756 43.288 44.498 44.740 44.981 45.222 45.463 44.959 46.790 48.805 51.036 63.516 ' 45.704 45;646 46.187 46.428 ' 46.670 56.291 69.416 62.958 67.007 71.681 77.142 46.911 47.153 47.394 47.636 47.877 48.119 * Compiled by John A. Goff end S. Gratoh. 601.1 627.1 654.7 684.1 715.2 ' 643.2 669.4 697.3 726.9 758.3 0.07756 0.07794 0.07832 0.07870 0.07908 1.005 1.047 1.091 1.137 1.187 ' 1.083 1.125 ; 1.169 ' 1.216 1.266 748.5 783.9 821.9 862.5 906.2 791.8 827.4 865.7 906.5 950.5 0.07946 0.07984 0.08021 0.08059 0.08096 1.240 .1.296 1.357 1.421 1.490 1.319 . 1.376 ' . 1.437 1.602 1.571 953.2 1004 1069 1119 1184 997.7 ` 1049 1104 1164 ' 1229 0.08134 0.08171 0.08208 0.08245 0.08283 . 1.665 * 1.645 1.731 1.825 1.928 1.646 1.727 1.813 a 1.907 2.011 1255 1332 1418 1513 1619 1301 1378 1464 1559 1666 0.08320 0.08357 0.08394 0.08431 0.08468 2.039 2.161 2.296 2.444 2.609 2.122 2.245 2.380 2.628 2.694 1737 1871 2022 2195 2395 2629 1784 1918 2069 2243 2443 2677 0.08505 0.08542 ' ' 0.08579 0.08616 0.08653 0.08689 2.794 3.002 3.238 3.507 3.817 4.179 2.879 ` 3.087 3.324 3.693 ' 3.904 4.266 . Condensed Water Enthalpy Btu/Lo Aw Entropy Bt(4> > 0w Vap. Press In. Hg . Pa Fahb. Temp. 1(F) 143.02 144.02 - 145.02 146.03 147.03 148.03 149.03 150.04 151.04 ' 162.04 163.05 154.05 155.05 166.06 157.06 158.07 159.07 160.07 161.08 162.08 163.00 164.09 165.10 166.10 167.11 168.11 0:2553 0.2568 0.2584 012600 0.2616 13.675 13.987 14.304 14.628 14.958 175 176 177 178 179 . 0.2631 0.2647 '0.2662 0.2678 0.2693 15.294 15.636 15.985 16.340 16.702 180 181 182 183 184 0.2709 0.2724 0.2740 0.2755 0.2771 17.071 185 17.446 186 17.828 187 18.217 188 18.614 , 189 0.2786 0.2802 : 0.2817 0.2833 0.2848 1 ' 0.2864 0.2879 0.2895 0.2910 0.2925 0.2940 19.017 19.427 19.845 20.271 20.704 21.145 21.59422.050 22.614 22.987 23.468 190 191 192 193 194 195 196 197 198 199 200 1 Table 3. Thermodynamic Properties of Water -at Saturation* Fahb. ' Temp. ((F) Absolut hi Pressure Pa X 10* ` Lb/Sq In. In. Hg , Specific Volume, cu ft pbre lb Sat. Solid Evap. vig X 10-* Sat. Vapor vt X lfc* Enthalpt, Btu per lb Sat. Solid . Ai : Evap. , Sat. Vapor Aig kg -155 --145 -125 --120 -105 --100 --95 --90 --85 -80 --75 --70 -65 --60 ' -55 --50 -48 --46 --44 -42 -40 . -38 -36 -34 --32 0.009040 0.01620 0.02850 0.04926 0.06380 0.1403 0.2312 0.3757 0.6019 0.9517 1.486 2.291 3.491 6.260' 7.841 11.57 16.89 24.43 35.01 , 49.72 70.01 97.76 111.5 127.0 164.1 186.1 211.0 238.8 270.0 304.9 0.01008 0.01840 0.03298 0.05803 0.01722 ' 0.01723 0.01723 0.01724 36070 20080' 11390 6577 - 0.1003 0.1706 0.2856 0.4708 . 0.01724 0.01726 0.01725 0.01726 3864 2308 1400 862.2 0.7649 1.226 1.938 3.025 > ' O.Q1726 0.01727 0.01728 0.01728 - 538 6 341.1 218.9 142.2 - 4.664 7.108 10.71 15,96 0.01729 0.01729 0.01730 0.01730 93.52 62.23 41.86 28.46 23.55 34.39 49.74 71.28 0.01731 . 0.01732 0.01732 0.01733 19.55 13.56 9.501 6.715 101.2 142.6 199.0 227.0 *0.01734 0.01734 0.01735 0.01736 4.788 3.443 ' 2.496 2.200 258.5 294.0 334.0 379.0 0.01736 0.01736 0.01730 0.01737 1.941 1.715 1.516 1.343 429.5 486.2 549.7 620.8 0.01737 0.01737 0.01737 0.01738 1.191 1.057 0,9391 ' 0.8355 36070 20080 11390 6577 -222.05 -220.44 -218.82 -217.17 1212.43 1213.02 1213.62 1214.17 - 990.38 962.58' 994.80 997.00 3864 2308 1400 862.2 -215-49 . -213.80 ' -212.08 -210.34 1214.70 1215.22 1215.71 1216.18 699.21 1001.42 1003.63 1005.84 638.6 341.1 218.9 142.2 -208.58 ' -206.79 -204.98 -203.14 1216.63 1217.06 1217.46 1217.82 1008.05 1010.26 1012.47 1014.68 . 93.62 62.23 41.86 28.46 -201.28 -199.40 1 -197.49 -195.50 ' 1218.17 1218.50 1218.80 1219.08 ` - 1016.89 1016.10 1021.311023.52 19.55 13.56 9.501 0.715 -193.60 -191.62 -189.61 -187.58 1219.33 1219.56 1219.76 1219.94 ' 1025.73 1027.94 1030.15 1032.36 4.788 3.443 2.496 2.200 -185.52 ` -183.44 -181.34 -180.49 1220.10 1220.23 . 1220.34 1220.37 1034.58 1036.79 1039.00 1039.88 1.941 1.715 1.516 1.343 -179.64 -178.78 --177.02 -177.06 1220.40 1220.43 1220.45 1220.48 1040.76 1041.65 1042,53 1043.42 1.191 1.057 0.9391 0.8355 -176.19 -175.32 . -174.45 -173.57 1220.46 1044.30 1220.51 1045.19 1220.52 1040.07. 1220.52 ' 1046.95 Compiled by John A. Goff and 8. Gratch. Entropy. Btu per (Lb) (F) Sat. Solid Evap. `ig : Sat. Vapor -0.4907 -0.4854 --0.4801 -0.4748- -0.4695 -0.4643 -0.4590 -0.4538 -0.4485 -0.4433 -0.4381 -0.4329 -0.4277 -0.4225 -0.4173 -0.4121 -0.4069 -0.4017 -0.3965 -0.3914 -0.3862 -0.3810 --0/3758 -0.3738 -0.3717 -0.3666 -0.3076 -0.3055 -0.3634 -0.3614 -0.3593 -0.3573 4.0456 3.9812 3.9188 3.8583 3.7996 3.7428 3.6874 3.6338 3.5815 3.53Q8 3.4815 3.4335 3.3868 3.3412 3.2969 3.2530 3.2114 3.1702 3.1301' 3.0910 3.0620 3.0152 2.9786 2.9643 . 2.6501 2.9356 2.9219 . 2.6080 . 2.8942 . 2.8807 2.8071 2.8538 3.5549 3.4958 3.4387 3.3835 3.3301 3.2785 3.2284 3.1800 3.1330 3.0875 3.0434 3.0006 2.9591 2.9187 2.8796 2.8415 2.8045 2.7685 2.7336 2.6998 2.6664 2.6342 2.6028 -2.5905 2.5784 2.5663 2.5543 . 2.5425 2.5308 2.5163 2.6078 2.4965 Fahb. Temp, ((F) -160 -155 -160 -145 -140 -135 -130 -125 -120 -115 -110 -105 -100 -95 -90 -85 -80 -- ib -70 --65 -60 --55 --60 -48 -40 --44 -42 -40 -38 -36 -34 -32 U> 1952 Guide $1 Thermodynamics Table 3. Thermodynamic Properties op Water at Saturation* (Continued) Fahb. Temp. ((F) Absolute Pressure' Pa X 10* Specific Volume, cu FT PER LB Lb/Sq In. In, Hg Sat. Solid ' ti; Evap. vu X .10-< Sat. Vapor vg X 10-* -30 -28 -20 -24 -22 -20 -19 -18 -17 -16 -15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 .2 3 4 6 6 0:3440 0.3876 0.4363 0.4905 0.5509 0.6181 0.6545 0.6928 0.7332 0.7757 0.8204 0.8070 0.6172 0.6694 1.024 1.082 1.143 1.207 1.274 1.344 1.419 1.496' 1.578 1.664 1.754 1.849 1.948 2.052 2.161 2.276 2.396 2.521 - 0.7003 0.7891 0.8882 0.9987 0^01788 0.01738 0.01738 0.01739 1.122 1.269 1.333 1.410 . 0.01739 0.01730 0.01739 0.01740 1.493 1.579 1.070 1.760 0.01740 0.01740 0.01740 0.01740 1.887 1.974 2.080 2.203 0.01740 0.01740 0.01740 0.01741 2.327 2,457 4.894' 2.737 0.01741 0.01741 0.01741 0.01741 2.888 3.047 3.213 3.388 0.01741 0.01744 0.01742 0.01742 3.572 3.764 3.666 4.178 0.01742 0;01742 0.01742 0.01742 4.400' 0.01743 4:033 . 0.01743 4.878 - , 0.01743 6.134 0.01743 Compiled by John A. Goff and 8. Gratch. 7.441 6.634 5.921 5.290 4.732 4.237 4.011 3.707 3.899 3.407 3.228 3.000 2.901 2.750 2.009 2.475 2.349 2:229 2.110 2.010 1:909 1.814 1:723 1.638 K557 1.481 1.408 1.840 1.275 1.214 ..... 1,155 1.100 7.441 6,634 5.921 5.290 4.732 4.237 4.011 3.707 3.696 3.407 3:228 3.000' 2^901 2.750 2.609 2.475 2 .'349. 2.229 2.116 2.010 L909 1.814 1.723 1.638 1.557 1.481 1.408 1.340 1.275 1.214 . 1.155 1.100 . Enthalpy Btu per lb Entropy, btu per (Lb) (*F) Sat. Solid Ai- Evap. Aig Sat. Vapor A* Sat. Solid Evap. tg,- Sat. Vapor ; se < Fahb. temp. ((F) -172.08 -171.80 -170.91 -170.01 -169,12 -168.21 -187.70 -167.31 -166.85 -100.40 -165.94 -165.48 -165.03 -164.67 -164.11 -163.65 -183.18 -162.72 -162.26 -101.79 -101.33 -160.86 -160.39 -159.92 -159.45 -158.98 -168.51 -158.04 -157.50. -157.09 -166.61 -156.14 ' 1220.52 1220.52 1220.51 1220.50 1047.84 1048.72 1049.60 1050.49 -0.3552 -0.3532 -0.3511 -0.3490 1220.49 1220 .*47 1220.46 1220.48 1051.37 1052.20 1052.70 1053.14 . -0.3470 -0.3449 -0.3439 -0.3429 1220,43 1220.42 1220.41 1220.39 1053.58 1054.02 1054.47 1084.91 -0.3418 -0*3*08 -0.3398. -0.3388 1220.38. 1220.36 1220.34 1220.32 1055.35 1056.79 1056.23 1056.67 -0.3377. -0.3367 -0.3357 -0.3347 1220.30 1220.28 1220.26 1220.23 1057.12 1067.56 1058.00 1068.44 -0.3336 -0.3326 -0.3316 -0.3306 1220.21 1220.18 1220.15 1220.13 1058.88 1059.32 1069.76 1060.21 -0.3295 -0.3285 -0.3275 -0.3264 1220.10 1220.07 1220.04 1220.01 1060.65 1061.09 1061.53 1061.97 -0.8254 -0.3244 -0.8234 -0.3224 1219.97 1219.94 1219.90 1219.88 1062.41 1002.85 ~ 1063.29, . 1063.74 -0.3213 -0.3203 --0;3199 > -0.3182 2.8405 2.8274 2.8143 2.SOI3 . 2.7898 2.7757 2.7095 2.7632 2.7568 2.7606 2.7444 2.7383 2.7320 2.7289 2.7198 2.7138 2.7076 2.7016 2.6966 2.8896 2.6836 2.6777 2.6718 2.6658 2.6600 2.6541 2.0483 2.6425 2.6367 2.6309 2.6252 2.6194 ' 2.4853 2.4742 2.4032 2.4523 . --30 -28 -26 -24 2.4416 2.4308 2.4256 2.4203 -22 -20 -19 -18 2.4150 2; 4098 2,4046 2.3996 -17 -.16 -15 -14 2:8943 2.3892 2.3841 2.3791 -13 -12 -11 -10 2.3740 2.3690 2.8640 2.3596 --9 **.8 ' -?7 -6 2.3541 2.8492 2.3443 2.3394 --4 -3 -2 2.3346 2.3297 2.3249 2.3201 --1 0 1 * 2.3154 2.8106 2.3059 2.3012 .3 4 5 6 0 CHAPTER 3 Table 3. Thermodynamic Properties of WATER at Saturation* (Continued) Fahb. /(F) 10 14 18' 19 20 21 2223 24' 25 26 27 28 29 30 31 32 32 ' Absolute Pbbssubb - v* . . Lb/8q In. In, Hg 0.02653 0.03087 0.03767 0.04581 0.04808 0.05045 0.05293 0.05562 0.05823 0.06105 0.06400 0.06708 0.07030 0.07365 0.07715 0.08080 0.08461 0.08858 0.088586 0.05402 0.05683 0.05977 0.06286 0.06608 0.06946 0.07300 0.07669 0.08056 0.08461 0.08884 0.09326 0.09789 0.1027 0.1078 0.1130 0.1186 0.1243 0.1303 0.1366 0.1431 0.1500 0.15711 0.1645 0.1723 0.1803- 0.18036 Specific Volume, cu ft peb lb Enthalpy, Btu peb lb .. r;Vi 0.01743 0.01743 0.01744 0.01744 0.01744 0.01744 0.01744 0.01744 0.01744 0.01745 0.01746 0.01745 0.01745 0.01745 0.01746 0.01746 0.01746 0.01746 0.01746 0.01746 0.01746 0.01746 0.01747 0.01747 0.01747 0.01747 0.01602 1 Vig. 10480' 9979 9507 9060 8636 8234 . 7861 7489 7144 6817 6605 6210 5929 5662 6408 5166 4936 ' 4717 4609 4311 . 4122 3943 3771 3608- .3463 3305. 3304.6^ Sat. Vapor . . Vg . Sat. Solid hi Evap. Aig' ' 10480 9979 9507 6060 --155.66 -165.18 -154.70 -154.22 1219.84 1219.80 1219.76 1219.72 8636 8234 7861, 7489 -153.74 -163.26 -152.77 -152.29 ' 1219.68 1219.64 1219.59 1219.56 7144 6817 6505 6210' -161.80 -151.32 -150.83 - -150.34 1219.50 1219.46 1219.41 1219.36 6929 ' 5662 ' 5408 6166' -149.86 - -146.36 -148.87 -148.38 1219.31 1219.26 1216.21 1219.16 4936' 4717 4509 4311 " -147.88 -147.39 -146.89 ' -146.40 ' 1219.10 1216.05 1218.98 1218.93 4122 3643 3771 3608 -145.90 -146.40 -144.90 -144.40 1218.87 1218.81 1218.75 1218.69 . 3453. ,, ,3305'.' - -143.90 -143.40 1218.63 1218.66 3304.6 0.00 1075.16 ` Sat. Vapor . hg 1004.18 1064.62 1065.06 1085.50 1065.94 1066.38 1066.82 1067.26 1087.70 1068.14 1068.58 1069.02 1069.46 1069.90 1070.34 1070.78 1071.22 1071.66 1072.09 1072.63 1072.97 1073.41 1073.85 1074.29 1074.73 1075.16 1075.18 Entbopy, Btu peb (Lb) (F) Sat. Solid ' i.- Evap. *ig - Sat. Vapor Fahb. Temp. 1(F) -0.3172 -0.3182 -0.3152 -0.3142 -0.3131 -0.3121 -0.3111 -0.3101 -6.3090 -0.3080 -0.3070 -0.3060. -6.3049 -0.3039 -0.3029 -0.3019 -6.3008 ,-0.2698 ' -0:2988 -0.2978 -0.2968 -0.2957 -0.2947 -0.2937 -0.2927 -0.2918 0.00000 2-6138 2.6081 2.6025 2.6969 2.11912 2.6867 2.5801 2.5746 2.5690' 2.6635 2.6681 2.5526 2.5471 2.6417 2.6864 2.6310 2.5256 2.6203 2.6160 2.6097 2.5045 2.4991 2.4939 2.4887 2.4836 2.4783 2.1867 ' 2.2066 2.2919 2.2673 2.2827 2.2781 2.2736 2.2690 2.2646 2.2600 2.2565 2.2511 2.2466 2,2422 2.2378 2 7 8 9 10 11 12 13 14 15 16 17 18 19 21 2.2248 ' 2.2205 23 2.2119 2.21)77 2.2034 2.1992 2.1950 . 27'. 2.1908 2.1867 31 , 2.1867 . . .32* * Compiled by John A. Goff and 8. Gratehl . ... * Extrapolated to represent metastable equilibrium with undercooled liquid.- i 1952;Guide | | | Thermodynamics Table 3. Thermodynamic Properties of Water at Saturation* (Continued) Fahb. Temp. /(F) Absolute Pbbssubb p* Specific Volume, cu ft peb lb. Enthalpy, Btu peb lb Lb/8q In. In. Hg Sat. Liquid W Evap. Vfg Sat/ Vapor Sat. Liquid - v8 ht Evap. Afg Sat. Vapor Ag 32 0.( 0.18036 0.01602 3304.6 33 0.092227 0.18778 0.01602 3180.6 34 0.095999 0.19546 0.01602 3061.7 33 0.099908 0.20342 0.01602 2947.8 36 0.10396 0.21166 0.01602 2838.7 37 0.10815 0.22020 0.01602 2734.1 38 0.11249 0.22904 0.01602 2633.8 39 0.11699 0.23819 0.01602 2637.6 40 0.12164 0.24767 0.01602 2445.4 41 0.12646 0.26748 0.01602 2366.9 42 0.13145 0.26763 0.01602 2272.0 43 0.13660 0.27813 0.01602 2190.5 44 0.14194 . 0.28899 0.01602 2112.3 46 0.14746 0.30023 0.01602 2037.3 46 0.15317 0.31186 0.01602 1966.2 47 0.15907 0.32387 0.01602 1896.0 48 0.16617 0.33629 0.01602 1820.5 49 0.17148 0(34913 0.01602 1765.7 60 0.17799 0.36240 0.01602 1704.3 61 0.18473 0.37611 0.01602 1646.4 63 0.19169 0.39028 0.01602 1588.-7 63 0.19888 0.40492 0.01603 1634.3 64 0. 20630. 0.42003 0.01603 1481.9 66 0.21397 0.43664 0.01603 .1431.5 66 0.22188 0.46176 0.01603 1383.1 67 68 0.23006 . '0.23849 0.46840 0.48658 0.01603 0.01803 1336.6 1291-7 69 0.24720 0.60330 0.01603 1248.6 60 0.25618 0.52160 0.01603 1207.1 61 0.26645 0.64047 0.01604 1167.2 3304.6 3180.5 3061.7 2947.8 2838.7 2734.1 2633.8 2637.6 2446.4 2366.9 2272 lb 2190.6 2112.3 2037.3 1965.2 1896.0 1829.5 1765.7 1704.8 1646.4 ,1588.7 1634.3 1481.9 1431;5 1383.1. 1336.5 1291.7 1248.6 1207.1 1167.2 0.00 1.01 ` 2.01 5.03 9.05 10.06 ii.ua 14.06 15.06 . 1/.0/ 20.07. 21.0/ 24.08. 25.08. 1075.16 1074.69 1074.03 1073.40 1072.90 1075.18 1075.60 1076.04 1076.48 1076.92 1072.33 1071.77 1071.20 1070.64 1070.06 1077.38 1077.80 1078.24 1078.68 1079.11 1069.50 1068.94 1068.37 1067.81 1067.24 1079.55 1079.99 1080.43 1080.87 1081.30 1068)68 1066.11 1065.55 1064.99 1064.42 1081.74 1082.18 1Q82.62 1083.06 1083.49 1063.86 1063.30 1062.72 1062.16 1061.60 . 1083.63 1084:37 1084.80 1085.24 1085.68 1061.04 1060:47 1069.91 1069.34 1068.78 1086.12 ' 1086.55 1086.99 1087.42 - : 1087.88 * Compiled by John A. Goff and S.'Gratoh. Extrapolated to represent metaatable equilibrium with undercooled liquid.' Entbopy, Btu peb (lb) (F) Sat. Liquid 0.00000 0.00205 0.00409 0.00612 0.00815 0.01018, 0.01220 0.01422 0.01623 0.01824 0.02024 0.02224 0.02423 0.02622 . 0.02820 0.03018 0.03216 0.03413 0.03610 0.03806 0.04002 0.04167 0.04392 0.04587 .0.04781 0.04975 0.05168 0.05381 0.05553 0.05746 Evap. g Sat. Vapor g `. . 2.1867 2.1811 2.1755 2.1700 2.1644 2.1867' 2.1831 . 2.1761. 2.1726 2.1589 2.1535 2.1480 2.1426 2,1372 2.1691 2.1657' 2.1588 . 2.1654 2.1318 2.1265 2.1211 2.1168 2.1105 2.1520 2.1487 2.1453 2.1387 2.1052 2.0999 2.0947 2.0895 2.0842 2.1354 2.1321 2.1288 2.1266 2.1223 2.0791 2.0739 2.0688 2.0637 2.0586 2.1191 2.1159 2.1127 2.1096 2.1064 2.0535 2.0485 2:0434 2.0385 .2.0334 . .2.1033 - 2.1002 2.0970 2.0940 - 2.0909 Fahb, Temp. *(F) 36 41 48 . 48 50 51 56 57 58 60 . . 61 ..-4 fi. Table 3. Thermodynamic Properties of Water at Saturation* (Continued) Fabb. Temp. t(F) Absoluts Pbessubb : Lb/8q In. In. Hg . Specific Volume, cu ft pub lb - Enthalpy.. Btu per lb . ' Entropy, Btu per (lb) (F) Sat. Liquid vt ' Evap. toSat. Vapor Sat.Liquid Fg Evap.' tog Sat.'Vapor - Sat. Liquid hg Evap. efg Sat. Vapor *g Fahr. Temp. F) 62 63 64 66 66 67 68 69 70 71 72 73 * 74 75 76 77 78 79 80 81 82 83 84 88 . 86 87 88 89. so 91 0.27602 0.28488 0.29606 0.30664 0.31636 0.32760 0.33900 0.36084 0.36304 0.37661 . 0.38856 0.40190 0.41664 0.42979 0.44436 0.45936 0.47478 0.49066 0.60701 0.62382 0.54112 0.85892 0.87722 0.59604 0.61640 ,0.63530 0.65575 0.67678 0.69838 0.72059 0.66994 0.68002 0.60073 0.62209 0.64411 0.666&1 0.69021 0.71432 0.73916. 0.76476 0.79113 0.81829 0.84626 0.876060.90472 .0.93624 0.96666 0.99900 1.0323 1.0665 1.1017 1.1380. 1.1762 1.2136 1.2630 1.2935 1.3351 1.3779 1.4219 1.4671 0.01604 0.01604 0.01604 0.01604 0.01604 0.01605 0.01605 0.01605 0.01605 0.01606 0.01606 0.01606 . 0.01606 0.01606 0.01606 0.01607 ,0.01607 0.01607 0.01607 0.01608 . 0^01608 0.01608 0.01608 0.01609 0.01609 0.01609 0.01610 0.01610 0.01610 0.01610 Compiled by John A. Goff and 8. Gratch. 1128.7 1091.7 1056.1 1021.7 988.63 956.76 926.06 896.47 867.95 840.46 813.96 788.36 763.73 739.95 '717.01 694.88 673.52 662.91 633.01 613.80 595.25 577.34 660.04 543.33 527.19 611.60 496.62 481.96 467.88 464.26 1128.7 1091.7, 1056 A 1021.7 988.65 866.78 926.08 896.49 867.97 840.47 813.97 788.40 763.75 739.97 717.03 694.90 673.54 662.93 633.03 613.82 595.27 577.36 560.06 543.35 527.21 511.62 4QQ.S4 481.98 467.90 454.28 30.08 81.08 32:08 33.08 84.07 35.Q.7 36.07 37.07, 38.07 39.07 40.07 41.07 42.06 43.06 44.06 45.06 46.06 47.06 48.06; 49.05 50'05` 61.06 62.05 63406 54.04 55.04 56.04 . 57.04 . 58.04 60.03 .................. 1058.22 1057;65 1057.09 1056.62 1055.97 1055.40 .1054;84 1054.27 1053.71 1053.14 1052.68 1052.01 1051.46 1060.89 1050.82 1049.76 1049.19 1048.62 1048.07 1047.50 1046.93 1048.37 1045;80 1045.23 1044.67 1044.10 1043.54 1042.97 1042.40 1041.84 1088.80 1088.73 1089.17 1089.60 1090.04 1090.47 1090.91 1091.34 1091.78 1092.21 1092.65 1093.08 1093.62 1093.96 1094.38 1094.82 1095.26 1096.68 1096.12 1096.55 1096.98 1097.42 1097.85 1098.28 .1098.71 1099.14 1099.68 1100.01 1100.44 1100.87 0.05937 0.06129 0.06320 0.06510 0.06700 0.06890 0.07080 0.07269 0.07458 0.07646 0.07834 0.08022 0.08209 0.08396 0.08582 0.08769 0.08954 0.09140 0.09325 0.09510 0.09694 0.09878 0.10062 0.10246 0.10429 0.10611 0.10794 0.10976 0.11158 0.11339 2.0284 2.0235 2.0186 2.0136 .2.0087 . 2.0039 1.9990 1.9941 1.9893 1.9846 1.9797 1.9749 1.9701 1.9664 1.9607 1.9560 1.9513 1.9466 1.9419 1.9373 1.9328 1.9281 1.9236 . 1.9189 1.9144 1.9099 1.9054 1.9008 1.8963 1.8919 2.0878 2.0848 2.0818 2.0787 2.0757 2.0728 2.0698 2.0668 2.0639 2.0610 '2.0580 2.0551 2.0622 2.0494 2.0465 2.0437 2.0408 2.0380 2.0352 2.0324 ; / 2.0297 2.0269 2.0242 2.0214 2.0187 , ,2.0160 2:0133 2.0106 2.0079 2.0053 . 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 mmsam i n pi w w (jJ iOn to O A oa. Table 3. Thermodynamic Properties op Water at. Saturation11 (Continued) Fahr. Temp. m Absolute Pbessubb p ' -Specific Volume, cu ft pbb lb Enthalpy,* Btu per lb '. Entropy, Btu per (lb) (*F) Lb/Sq In. In. Hg Sat. Liquid VI Evap. Sat. Vapor Sat. Liquid Vf .. to Evap. tog Sat; Vapor Sat. Liquid A* . , f Evap. I* Sat. Vapor g 92 93 94 95 96 ' 97 98 '99 101 102 103 104 105 106 107 108 100 110 111 112 113 114 115 116 117 118 . 119 ' 120 121 0.74340 0.76684 0.70091 0.81564 0.84103 0.86711 0.89388 0.02137 0.04030 0.97854 1.0083 1.0388 1.0700 1.1021 1.1351 1.1688 1.2036 1.2390 1.2754 1.3128 1.3510 1.3902 1.4305 1.4717 1.3139 i;567i 1.6014 1.6468 1.6933 1.7409 1.5136 1.5613 1.6103 1.6607 1.7124 1.7655 1.8200 1.8759 1.9334 1.9923 2.0529 2.1149 2.1786 2.2440 2.3110 2.3708 2.4503 .2.5226 2.5968 2.6728 2.7507 2.8306 2.9126 2.9963 3.0823 3.1703 3.2606 3.3530 3.4477 3.6446 0.01611 0.01611 0.01611 0.01612 0.01612 0.01612 0.01612 0.01613 0.01613 0.01614 Mien 0.01614 0.01614 0.01615 0.01015 0.01616 0.01616 0.01616 0.01617 0.01617 0.01617 0.01618 0.01618 0.01618 0.01619 0.01619 0.01620 0.01620 0.01620 0.01621 441.10 428.38 416.07 404.17 392.65 S8'i.51 370.73 360.30 350.20 340.42 330.96 321.80 312.93 304.34 296.02 2$7.96 280.14 272.58 265.24 258;14 251.25 244.57 238.10 231.82 225.73 . 219.83 214.10 208.54 203.16 197.93 441.12 428.40 416.09 404.19 392.67 381.53 370.75 360.32 350.22 340.44 830.08 321.82 312.65 304:36 296.04 287.68 280.16 272.60 265.26 258.16 Mi: 27 244.59 238.12 231.84 225.75 219.85 214.12 208.56 203.18 197.95 60.03 61.03 62.03. 63.03 64.02 65.02 66.02 67.02 68.02 69.01 - 70.01 71.01 72.01 73.01 74.01. 76.00 76.00 77.00 78.00 79.00 80.00 80.99 81.99- 82.99 83.99 ' 84.99 85.69 86.98 87.68 68.98 1041.27 1040.70 1040.13 1039.66 1039.00 1038.43 1037;86 1037.26 1036.72 1036;16 1035.58 1035.01 1034.44 1033.87 1033.29 1032.73 1032.16 1031.68 1031.01 . 1030.44 1029.86 1029.30 1028.72 1028.15 1027.57 1026199 1026.42 1025.85 1025.28 1024.70 1101.30 1101.73 1102.16" 1102.69 1103.02 0.11520' 0.11701 0.11881 0.12061 0.12241 1103.45 1103;88 1104.31 1104.74 1105.17 U05.59 1106.02 1106.45 1106.88 1107.30 0; 12420 0.12600 0.12778 0.12967 0.13135 0.133i3 0.13490 0.13667 0.13844 0.14021 1107.73 1108.16 1108.58 1109.01 1109.44 044197 . 0.14373 0.14546 0.14724 . 0.14899 1109.86 1110.29 1110.71 1111.14 1111.56 0.15074 0.15248 0.15423 0.15696 0.15770 1111.98 1112.41 1112.83 1113.26 1113.68 0.15943 0.16116 0.16280 0.16461i 0.16634 1.8874 1.8830 1.8786 1.8741 1.8698 1.8654 1.8610 1.8566 1.8523 1.8480 1;8437 1.8394 1.8351 1.8309 1.8266 1.8224 1.8182 1.8140 1.8068 1.B056 1.8016 1.7073 1.7932 1.7800 1.7849 1.7809 1.7767 1.7727 1.7687' 1.7647 2.0026 2.0000 . 1.9974 1.9647 . . 1.9922 1.6896 1;9870 1.9844 1.9816 1.9793 1.97*68 1;0743 1.9718 1.6693 1.0668 1.9644 1.6619 1.9595 1.0570 1.9546 1.9522 1.9498 1.9474 1.9450 1.9426 1.6403 1.9379 1.6356 1.9333 1.9310 * Compiled by John A. Goff and S. Gratch. : / ' ; v; . / ;< . <,: Fahr. Temp. , ((F) 92 93 94 95 96 07 98 99 100 101 102 103 104 105 106 107 108 109 110 in 112 113 114 115 116 117 118 119 120 121  -Lv'1 jj \ Table 3. Thermodynamic Properties of Water at Saturation* (Continued) Fahr. Temp. ((F) Absolutb Pressure ` P Lb/Sq In. In. Hg Specific Volume, cu FT PER LB . .Enthalpy, Btu per lb ; > r; Entropy, Btu per (lb) (?F).;, Sat; Liquid vf Evap. Vfg Sat.' Vapor Sat; 'Liquid Vg Af Evap. , . V* V . Sat Vapor v Ag , . Sat; Liquid M Evap: sfg Sat. Vapor . Fahr. Temp. ((F) 122 123 124 125 126 . 127 128 129 130 131 132 133 134 135 136 137. 138 139 140 141 142 143 144 145 146 147 148 149 150 151 1.7807 1.8396 1.8907 1.0430 1.9966 2.0514 2.1075 2.1649 2.2237 2.2838 - 2.3452 2.4081 2.4725 2.5382 2.6055 2.6743 2.7446 2.8166 2.8900 2.9651 . 3.0419 3.1204 3.2006 3.2825 3.3662 ' 3.4517 3.5390 3.6282 3.7194 3.8124 ` 3.6439 3.7455 3.8496 3.9561 4.0651 *4.1768 4.2910 4.4078 4.5274 4.6408 4.7750 4.9036 5.0340 5.1679 5.3049 5.4450 5.5881 5.7346 5.8842 0.0371 6.1934 6.3532 6.5164 6.6832 6.8536 7.0277 7.2050 7.3872 7.5727 7.7622 0.01621 0.01622 0.01622 0.01622 0.01623 0.01623 0.01624 0.01624 0.01625 0.01625 0.01626 0.01626 0.01626 0.01027 0.01627 0.01628 0.01628 0.01629 0.01629 0.01630 0.01630 0.01631 0.01631 0.01632 0.01632 0.01633' 0.01633 0.01634 0.01634 0.01635 192.85 187.93 183:15 178.51 174.00 169.63 165.38 161.26 157.25 153.36 149.58 145.91 142.34 138.87 135.50 132.22 129.04 125.94 122.94 120.01 117:16 114.40 111.70 109.09 106.54' 104.06 101.65 99.306 97.022 94.799 `192.87 187.95 183.17 178.53 174.03 169.65 165:40 101.28 167.27 163.38 149.00 146.93 142:36 138.89 135.52 132.24 129.06 126.96 122.96 120.03 117.18 114.42 111.72 109.11 106.66 104:08 101.67 99:322 97.038 94.815 89.98 90.98 91.98 92.98 93.98 94:97 95.97 06.97 97.97 98.97 .99.97 100.97 101.97 102.97 103:97' 104.97 105.97 100.97 107.96 108.96 109.96 110.96 111.96 112.96 113.96 114.96 115.66 116.96 117.96 ` 118.96 ' 1034.13 1023.54 1022.96 1022.39 1021:81 1021.24 1020:66 1020:08 1019.50 1018:92 1018.34 1017.76 1017.18 1016.59 1016.01 1016.43 1014.85 1014.20 1013.69 1013.11 1012:62 1011:64 1011:36 1010,77 1010.18 1009.59 1009.01 1008.42 ' '1007.83 1007.24 1114:10 1114:52 1114.94 . 1115.37 1115.79 1116.21 1116:63 1117:05 1117.47 1117:89 1118:31 1118:73 1110:15 1119.56 1119:68 1120:40 1120:82 - 1131:33 1121.65 1122.07 1122:48 1122.00 1123:31 1123.73 1124.14 1124:55 ; 1124.97 1125.38 1125.79 1126.20 0:16805 0:16977 0:17148 0.17319 0:17490 0.17660 0.17830 0.18000 0.18170 0;18339 0.18508 0.18676 0.18845 0.19013 . 0:16181 0.19348 0:19516 0.19683 0.10850 0.20016 0.20182 0.20348 0:20514 0.20676 0.20845 ' 0.21010'' 0.21174 0.21339 0.21503 0.21067 1.7606 1:7666 1.7626 1.7486 I: MW 1.7407 1:7367 1:7328 1.7289 1:7250 1:7211 1.7172 1.7134 1.7095 1.7050 1.7018 1.6679 1.6942 1.6903 1.0865 1.6828 1.0790 1.0753 1.6715 1.6678 1.6641 1.6604 1.0567 ;1.6530 ' 1.6493 1.9286 1.9264 1.0241 1.9318 1:9165 1.9173 1.9130 1.9133 1.9106 1.9084 1.9062 1.9040 1.9018 1.8996 1.8974 1.8953 1.6931 1.8910' .1.8888 1.8867 , 1.8846 1.8825 1.8804 1.8783 1.8783 ' 1.8742 . 1.8731 1.8701 .- <1:8080 1.8660 ' 122 123 124 125 120 127 138 129 130 131 132 133 134 136 136 137 138 140 141 142 143 144 145 147 148 150 15t , * Compiled by John A. Goff and S. Gratoh. o 11952 Guide Thermodynamics Table 3. Thermodynamic Properties of Water at Saturation" (Continued) Fahr. Temp. ((F) Absolute Pressure . p* Lb/a'q In. In. Hg Specific. Volume cu PT PER LB ' , Enthalpy, Btu pbA lb ; - ; Entropy, Btu. per (lb) (F) - Sat. Liquid tit - Evap. Vfg Sat. Vapor Sat. Liquid Vg Af ' Evap. Afg Sat. Vapor Sat. Liquid Ag " *( Evap. gfg - 1 Sat. Vapor *g Fahr. Temp. ((F) 152 3.9074 153 . 4.0044 154 4.1036 155 4.2046 156 4.3078 7.9556 8.1532 8.3548 8.5607 , 8.7708 0.01635 0.016361 0.01636 0.01637 0.01637 92.635' 90.628" 88.477 86.460 84.536 02.651 90:644 88.493 86.496 . 84.652 ' 119.96 120.67 121.97 122.67 123.97 1006.96 1006.06 1005147 1004.88 1004.29 1126.62 1127.03 1127.44 1127.85. 1128.26 0.21830 1.0457 0.21994 1:6421- 0.22157* 1.6384 0.22320-1 1.6348 0.22482 . 1.6312 1.86401.8620. 1,8600 1;8580 1.8560 152 153 154 156 156 157 4.4132 8.9853" 0.01638 82.642 158 4.5207 0.2042 - 0.01638. 80.798 169 . 4.6304 0.4276 0.01639: 79t00r 160 4.7424 9.6556 0,01039 77,.251 161 . 4.8866 ' 9.8882 0.01640 75.546 162 4.9732 10.128 0.01640 73.885 163 6.0931 10.368' 0.01641 72.267 164 8.3134 10.615 0,01642 . 70.690 165 5.3372 10.867 0.01642 69.153 166 5.4634 11.124 0.01643 67.654 82:658 80.814 79.017 77.267 75.662^ 73.901. 72.283 70:700' 69.169 67.070, 124.97 125.97 ' 120.97127.97 128.97 129.97 130.96 131.08, ; 132.98, 133.98 1003.70 1003.11. 1002.51 , 1001-92 1001.33 1128:67 1129.08 1129.481 1129.89: 1130.30 1000.74' 1000.13 999.54' 968.64: 998.35 1130.71? 1131. 11': U3l;5ffl. 1131.92. . 1132.33 0.22645: 0:22807' 0.229691 0:23130' 0.23292 . ' 0.234530.-23614' 0:23774- 0.23035 0.24095 1.0270 1.8540 1.6239 1.6204: 1.8520 1.5501; 1.6168-- 1.8481' 1.6133 1.8462 .. , 1.6097* r.0002- 1.6027 1.8442 1.84281 1.8404 1.5990.- 1; 8384-: 1,5950 . 1.8365 157 158 159160 161 162 163- ' 164 165166 167 168 169 170 171 '5.6621 6.7233 585li 8.8936 6.1338 LI.386 Ll;653; 11.925 12.203 12.487 0.01643 0.01644 0:01644: 0.01645 0.01645 66.194- . 04.770 63.382 62.029 00.710 60.210 64.786 63,3981 62.045 60.726 ' 134.98 135.98 136.99 137.99 138.99; . 097;75: ' 1132:73' ' o:jssr 097:16. . 1133.14* 0.24414 996.65 > 1133.54*. 0.24574 995:95: - 1133.94: 0.24733: 995.36 - 1134.35 0.24892 1.5920 1!.5887` 1.5852- 1-5817* 1.5782 1'8340* 1,8328 1.8309 1:8290" 1,8271 107' 168 169 170 ' 171 ' 172 173 174 175 170 0.2746' 6.4192 6.66660.7188 .6:8699 12.775 13.070 13.370 13.676 13.987 0.01640 0.016470.01047, 0.01648 0.01648 ' 59.423 58.168 56.944 55.750 54.586 ' 59.439 58.184. ; 56.960- 56.760' 64.602 . 139.99' 1.41.00 142.00: 143.00 . .144.00 994,76: 094.15.693.55': 992:65'' 662.35 1 1134'. 75i 1135.15 1135.557 1135.95 . 1136.35 0'.25051' 0.25209 0.25367' 0.25525-' 0.25683 i;5748 1.5713 1.5679' 1.5644r 1.6611 1.8253 1.8234' 1.8216 i:.8197; 1.8179 172 173' 174 175 170 177 .. 7:0259 14:305' . .0,01649 . 53!450 ` . ,53.400.-. . . 145:00. 091.75 : . .1136.75 * .0.25841 t 1.5577- 1.8161' j 177 1/9 7.3469 } .Aim 7.6801 14.629 14.669 ' 15.295 16.637. 0.01650 0.01650 0.01651' . 0.01651 52.341 61.260 ,50.203 ' 49.173 ' .. ' 52.357 51.270 50.220 49.100 ' 146.01 ' 991.14 ' 1137:15 ' ' 0.25998 147.01 ' 960.54' 1137.55 ' 0.26165 148.01. .... .989.63, . f, .1137.94 0.26312 149.02- ' 989.32* 1138.34 : 0.26468 1.5543 1.5508 1.5475;. 1.6442 1.8U3 1.8124 - 1.8106 1.8089 178 1iS7)9- - 181 * Compiled by John A. Goff and S. Gratoh. i 48 CHAPTER 3 1952 Guide Thermodynamics r:> 49 T a b l e 3 . T h e r m o d y n a m ic P b o p e b t ib s o f W a t e r a t S a t u b a t io n * (Concluded) ; fa<eEHaHfw1a-_, 5SS3S gssss sgss .ssg|3: SS|| SS252 1.7811 i;B B / 1.7760 ' 1.7744 1.7727 1.7711 1.7694 1 1:7678 1.7662 . 1.7646, 1.7629 1.7613 1.7597 1.7581 1.7565 : Sat. Vapor *g 1.8071 1.8053 1.8035 1:8017 1.8000 1.7082 . j 1.7065 1.7947 1 1.7930 1.7913 p-. "a j as . ba\ -*6P" n . > \ W |MM=iiil=tiii!!ili?S{;!?5iii . ----- Hill! h Aoas 1IIII.lllli-lllll 111!! ilil Sillll M' ooooo ooooo ooooo o o o o o .00000 ooooo. Sat.'Liquid ' h ,8a. ja : - -a GO atAts DH PQ VW 3 BHz W asasa-essss sssss sgss2:sssss ssssss II1II |S|S= S2|22=-|i|2S3!pS2 2222|S assss sssss-sgsES s<ssss;;5assss sssszz ifHill llg;:gfH^lllss;sills Isssll :Sg8S.-3Sgg , ggSgg ggsss ,-sssas S32SSS 3SSS3---32SSS SSS33-; 3SS23. SSSS5 3SESSS Sat. Vapor Sat. Liquid ig ht -ap~. . ' aBs' ' A 3S3SS ggSSS ssssss po -M. ..gO*3' wdSs,,. 32333-33383' Sill! -.SlsiliSSSSa. .388383 .assas ssjsss ssasg. ^ssss-scssgg ssssss >g 00' -'A - iOOlOlOlOll-OlOlOlOrO lOlOlOlOlO HOOOiOlOl IOSOOOiOi IOOlOlOiOlOl Sat. Liquid 6B aH ---` SB0T fl* -82333 222ES isssS.lssP 52222 2gg5S tills SSSS8 sills SSSSS slips KSS888 fats. . H* sa M-o>3 *aa< V .- ' cr-' 00 1r-o1cpo1o IIsll ooooo llill ooooo o81-8--8-2\^28222^232 225222:2 B : -23333' 83333 '33232 SSSSr 83888 888838' , Table,4. . Properties of SaTURATEDSteaM: Pressure Table* .. ;. ABS. , Specific Volcme Temp . Enthalpy . as p F t '-'Sat. , LiTquid :^T Sat. Evap. Lfd if,- r- Entbopy Sat. ,vr ' .Ji.i \Abs.- Sim. - p; . 0.25 0.50 ?.M 1.5 .2 40.23 - /y.iu * 91.72 101.14 8:88K g-01606 2423.7 lZi 0.01611 444.9 6.01614 339.2 8.28 26.86 38.47 47.05 59.71 69:10 1071.1 1060.6 1054.0 {88:2 S? 1079.4 1087.5 18?:? 1105.7 0.0166 0.0754 0.0914 0.1147 0.1316 m?-as2.1423 2.1589 2^0635 2.0387 2.0041 1.9797 : 0.25 8:S- 1.00 1.5 2 * 4 125.43 0.01622 176.7 93.34 1116.0 0.1738 1.7476 1.9214 4 6 8- 10 140.78 -S 152.24 161:49 120.72 108.67 S 120.13 129.38 1122.3 1127.0 1130.8 oS 0.2335 1.6881 1.8877 1.6454 , 1.8640 1.6121 1.8456 6 12 169.28 0.01644 ~ 63 .03 137.18 " QQft 7- 1133.9 0.2460 1.5847 1.8307 n afc ifr. 14 16 18 176.05 182.05 187.45 0.01648 0.01652 0.01655 54.55 48.14 43.11 143.96 149.98 155.39 992.6 988.9 985.7 1136.6 1138.9 1141.1 0.2568 0.2662 0.2746 1.5613 1.5410 1.5231 1.8181- ; :*f. 14,, !(: 1.8072 16 ' ' 1.7977 18 '* & 20 22 192.37 196.90 0.01658> ,39.07 0.01661 35.73 160.33 . m.7 .1143.Of 0.2822- 1.5069 1.7891 20 .. 164.87 979.8 '1144.7* 0:2891 1.4923 1,7814- '.'iO-,22 J * A 24 201.09 0.01664 32.94 169.09 977.2 1146.3 0.2955 1.4789 1.7744 24 i( 26 . 206.00 .0.01667 -.30.56 .173.03 974.8 1147.8 0.3014 1.4665 1.7679 26' 28 208.67 '0.01669 1 - 28;52 s 178,72 972.5* 1149.2 0.3069 1.4550 1.7619 - ';28: S' 30 212.13 '-0.01672 / . ?6*74 ;180.1fr ; 970.3, 1150.5 0.3122 .1.4442 1.7564 ;...30 .. , -A Lb/Sq In. 14.696 . 16 f 18 212.00 0.01672 216.32' : 0.01674 222.41 0.01679 26.80 24:75 22.17 180.07 970.3 1150.4 0.3120 1.4446 184.42- : 967.6. 1152.0 0.3184 1.4313 190.56 963.6 1154.2 0.3275: .1.4128 .Lb/Sq In. 1.7566 : 14.696 1.7497 - W 16 * - 1.7403. 18. 20 227.96 0.01683 20,089 196.16 960.1 1156.3 0.3356 1.3962 1.7319' * * 20 : ,-4; % 22 24 26 28 233.07 : 0.01687. 237.82 0.01691 242.25 0.01694 246.41 0.01698 18.375; 201.33 16.938' 206.14 15.715 210.62 14.663 214.83 956.8 953.7 950.7 947.9 /1158.1 1159.8 1161.3 1162.7 0.3431 0.3500 0.3564 0.3623 ,1.3811 1.3672 1.3544 1.3425 1.7242 22p 1.7172 ' 24 1.7108. ; 28 . 1.7048 ' ` ' 28 . " 30 250.33 0.01701 13.746 218.82 :945.3 1164.1 0.3680 1.3313 1.6993 30 1m 254.05 0.01704 12.940 222.59 942.8 1165.4 0.3733 1.3209 1.6941 32 257.58 0.01707 12.226 228.18 940.3 1166.5 0.3783 1.3110 1.6893 34 - *S 260.96 0.01709 11.688 229.60 938.0 1167.6 0.3831 1.3017 1.6848 36 264.16 0.01712 11.015 232.89 935.8 1168.7 0.3876 1.2929 1.6805 38 * 267.25 0.01715 10.498 236.03 933.7 1169.7 -0.3919 1.2844 1.6763 ,, . 40 - - ;ar: 270.21 273.05 0.01717 10.029 239.04 0.01720 ! '9.601 241.95 931.6 1170.7 0.3960 1.2764 1.6724 929.6 1171.6 0.4000 1.2687 1.6687 . 42 '-44-'. - -a 276.80 .0.01722' . ,9.209, 244.75 . 927.7 1172.4 0.4038 -1-2613 1.6652 * 46 1 $ 278.45 0.01725 ' 8.848' 247.47' 925.8 1173.3 .0.4075 .1.2542 1.6617 ' '48 - - i 1 . 50 52 ' 54 56 281.01 283.49 285.90 288.23 0.01727 0.01729 0.01731 0.01733 8.515 8.208 7.922 7.656 250.09 252.63 255.09 257.50 924.0 922.2 920.5 918.8 1174.1 1174.8 1175.6 1176.3 0.4110 0.4144 0.4177 0.4209 1.2474 1.2409 1.2346 1.2285 1.6585 1.6553 1.6523 1.6494 - 50 * ` 52 54 . 56 r 290.50 0.01736 7.407 259.82 917.1 1176.9 0.4240 1.2226 1.6466 58 rS- 292.71 0.01738 7.175 262.09 915.5 1177.6 0.4270 1.2168 1.6438 60 - V 294.85 0.01740 6.957 264.30 913.9 1178.2 0.4300 1.2112 1.6412 62 s 66 68 296.94 298.99 300.98 0.01742 0.01744 0.01746 6.752 266.45 6.560 268.55 6.378 270.60 912.3 910.8 909.4 1178.8 1179.4 1180.0 0.4328 0.4356 0.4383 1.2059 1.2006 1.1955 1.6387 1.6362 1.6338 64 66 68 J * ! . 70 . 72 74 76 78 80 302.92 304.83 306.68 308.50 310.29 312.03 0.01748 0.01750 0.01752 0.01754 0.01755 0.01757 6.206 . 6.044 5.890 5.743 - 5.604: , 5.472 272.61 274.57 276.49 278.37 280.21 282.02 907.9 906.5 905.1 903.7 902.4 901.1 1180.6 1181.1 1181.6 1182.1 1182.6 1183.1 0.4409 0.4435 0.4460 0.4484 0.4508 0.4531 1.1906 1.1857 1.1810 1.1764 1.1720 1.1676 1.6315 1.6292 1.6270 1.6248 1.6228 1.6207 ',.70 72 74 .76 . ' , 78 80 ; ' ' > 84 86 313.74 315.42 317.07 0.01759 0.01761 0.01762 ' `5.346 283.79 `899.7 5.226 285.53 -.898.5 5.111 287.24 897.2 1183.5 1184.0 1184.4 0:4554 0.4576 0.4598 1.1633 1.1592 1.1551 1.6187 1.6168 1.6149 -82 84 86 818.68 0.01764 5.001 288.91 895.9 1184.8 0.4620 1.1510 1.6130 . 88 1 . 90 92 94 98 320.27 321.83 323.do 324.87 0.01766 0.01768 0.01769 0.01771 4.896 4.796 4.699 4.606 290.56 292.18 293.78 295.34 894.7 893.5 892.3 891.1 1185.3 .1185.7 1186.1 1186.4 0.4641 0.4661 0.4682 0.4702 1.1471 1.1433 1.1394 1.1358 1.6112 1.6094 1.6076 1.6060 90 92 , 94 96 1 t j 100 150 200 300 400 500 -- 326.3b 327.81 358.42 381.79 417.33 467.01 0.01772 0.01774 0.01809 0.01839 0.01890 0.0193 0.0197 4.517 4.432 3.015 2.288 1.5433 -1.1613 0.9278 296.89 298.40 330.51 355.36 393.84 424.0 449.4 689.9 888.8 863.6 843.0 809.0 780.5 755.0 U86.8 1187.2 1194.1 1198.4 1202.8 1204.5 1204.4 0.4721 0.4740 0.5138 0.5435 0.5879 0.6214 0.6487 1.1322 1.1286 1.0556 1.0018 0.9225 0.8630 0.8147 1.6043 1.6026 1.5694 1.5453 1.5104 1.4844 1.4634 .98 100 150. 200. 300 . , 400 500 . Thermodynamic Properties of Steam, by J. H. Kenftr> and F. G. Keyes Inc., 1936 edition. 50 CHAPTER 3 -i 1952 Guide veniently used to interpolate-values for the enthalpy, specific volume, and entropy of moist air from, the data of Table ?. Within the estimated precision of the data of Table 2, at temperatures below 150 F, the volume v, enthalpy h, and entropy a,-of moist air -per "pound of dry air at any de gree'of saturation ^ may be computed from the simple relations: . : \-':v = r h ~ h& + , V. * '' . (27) ; . (28) (29) '4? 1? 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 fof 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 v which is defined as -' v "i'f s? s-\ -- a)A 1 + aWjt (30) where a denotes the ratio of the apparent molecular weight of dry air (28.966) to'the molecular weight of water (18.0.16) and is,equal to 1.6078. Table 5 gives the values of the coefficient A for several,higher temperatures, the .value of p at which the correction term v attains its maximum value, and the maximum value of term there attained-. v . The correction term for the enthalpy is _ <i(i -- >)B h ~ -i + aWiM (31) Table 5. Coefficients A, B, C Appeasing in Equations 30, 31, 32, Maximum Values of Corrections Defined by Equations 30, 31, 32. Degree of Saturation5 at Which These Maxima Occur, Pm.. Maximum Value of . Correction Defined by Equation 33. . Degree_of Saturation at Which This Maximum Occurs, pm. " (Standard Atmospheric Pressure) A(ft/lba) B: (Btu/lbm) C (Btu/F/ ' lb) Umax (/<*/lb.) &inax ' (Btu/lba) jjnax (Btu/F/ lb) , Mm 3max- (Btu/F/ Iba) Pm 0.0018 0.0042 0.0096 0.0215 0.0487 0.1169 0.3363 0.0268 0.0650 0.1439 0.3149 0.6969 1.636. 4.608 0.00004 0.00009 0.00020 0.00042 0.00091 0.00207 0.00567 0.0004 0.0010 0.0022 0.0047 0.0099 0.0207 0.0451 0.0069 0.0155 0.0332 0.0693 0.1418 0.2903 0,6180 0.00001 0.00002 0.00005 0.00009 0.00019 0.00037 0.00076 0.4925 0.4878 0.4805 0.4691 0.4511 0.4213 0.3662 0.0015 0.0025 0.0040 0.0065 0.0106 0.0179 0.0333 0.3650 0.3632 0.3602 0:3557 0.3485 0.3363 0.3129 Thermodynamics 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 asD.. r . Corrections for the entropy consist of two terms: s which is defined as m(1 - /PC , 1 + aW.^t. (32) and s, the so-called mixing entropy, which contributes the larger part of the error. The mixing entropy is defined as +l = 0.1579 [(1 + paW.) logio(l paW. - aaWdog10 fix) . - -- p(1 + aW,) logm(l + aW,] (33) Table 5 lists the values of the coefficient C, the maximum values of s and s and the values of, p at which they occur. The maximum s occurs at the. same degree of saturation as the maximum values of. t>. and h. . Fig. 3. Basic Coordinates of A.S.H.V.E. Psychrometric Chart THE ASHVE PSYCHROMETRIC CHART A psychrometric chart is a graphical representation of the thermo 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' energy5 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 1923,7-8 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 approximately 40. deg with, the humidity ratio axis. This is shown, in Fig. 3. 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, necessary for locating and describing states on the chart. The arrange- 52 CHAPTER 3 1952 Guide ment 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 ; Ca> . CB> DRY-BULB TEMPERATURE (0) Fio. 4. Arrangement op Families op Curves on AE.H.V.E. PSYCHROMETRIC 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 -conr 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 Qh -- hi)/(Wt --W:)........... ;. 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 changed 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. .' 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 . ......--~. ,/uaau. a uc uni imit6 at m3 saturation curve, or the point at which die 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 1952 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 on 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 sub-cooled 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.S.H.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, ft. = 19.221 Btu per lb of dry air and A, = 24.47 Btu per lb of dry air. Then ft at the specified conditions is 19.221 + 0.40(24.47) = 29.01. Btu per lb of dry air." . . Solution 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 2: 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, hi = 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. W* 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 t* = 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 8: 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 + iji = Ghi or ... iOi = G(,hi -- Ai) Thermodynamics 55 Fig. 6.. Illustration op Process op 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 lb of water vapor per lb of dry air; the.initial enthalpy is 4.804 + 0.80(2.302) = 6.646 Btu per lb of ary air; the final degree iof saturation is 0.001722/0.08149 = 0.02113; the final enthalpy is 28.841 + 0.02113(90.70) = 30.757 Btu per lb of dry air; the final volume is 14.611 + 0.02113(1.905) = 114.651 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 S; i = (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 (Ai -- hi)/(IF, -- Wi) = . The horizontal line 1-2, Fig. 7, then represents thelcondition line for the process, and the final state of the moist air must lie on this line. The final state is located at the fioint at which the 120 F dry-bulb temperature line crosses the condition line, and is abeled 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, . . .. ' . ,g, = (2q,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 i passes through successive states along the line IF = IF, = constant, until the saturation line is intersected'. The Fig. 7. Solution of Example 3 on A.S.H.V.E. Psychrometric Chart 56 CHAPTER 3 ' 1952. 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 i,. The final enthalpy is then A,; the liquid water formed is (IFi -- Wt), 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 Wi; 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(0.03763) " = 0.01837 lb of water vapor per 1b of dry air; the initial enthalpy is 22.827 + 0.50(40.49) = 43.072 Btu per lb of dry air; the humidity ratio at saturation at the yv Thermodynamics 57. cu ft per lb of dry air; and the final enthalpy is 34.2 Btu per lb of dry air. The solu tion of the problem is ' . ... 20,000 ,, , . . i9> = 4 X (43 -- 34.2) = 12^00 Btu per min. ; , The other method is to use an energy balance, . . . ;i?i 5= C[Ai -- Aj -- A:(Wi -- IF,)] . . i. The initial humidity, ratio ip 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;6oo : ; \. . . ' . ..: .... '. = -T147.4T X (4' 3 - 34'1 ~ 0.00`25 X 38.07) ;."...... '' ' . . ..= 12,130 Btu per min. . Fig. 8. ; Cooling of Aib at Constant Pressure Shown on A.S.H.V.E. PsYCHBOMETBIC CHABT 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,s 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 ! Gh\ = Ght -+ Gifflx -- JPa)Awa + i?a or . . i?a -- -- Ag -- (Wi -- -- x20 000 _-- (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 problem by use of the psychrometric chart. The simpler is to use the region to the left of the saturation line (Fig. 8). From point 1 draw a horizontal line on the chart 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, ................ ' - .................... - . .. 19 = G(hi -- A). ... The initial enthalpy is 43 Btu per lb of dry air; the initial specific volume is 14.4 Adiabatic Mixing of Two Steady .Flow Air Streams at Constant. Pressure The process is diagrammed in Fig. iO. By applying the principles of the con servation of mass and energy, three equations may be written; .Mass balance for the diy air, ` .. 1 7 1' *7 Gi + Gt =* Gj Energy-balance for the process, ' 7 ` .. 7 * GiAi -F'GjAt = GjA, * :' 77 7 ' -- Mass balance for the water vapor, . GilFi + G,W, = G,W, Eliminating Gj and combining, the three equations yield the equation,. . Ai ---Ai. Wj -- Wi Gj. - -... ' '>t" Ai -- Ar = IF, -- H,l.= Gi' . ; . . ...- ' /oil .:, px,aTnvk 6: Outside air at 0 F dry-bulb temperature And 0.80 degreGof*Saturation W n nom'xe^ adiabatically with recirculated inside air at 70 F dry-bulb temperature degree of saturation, in the ratio of one pound of dry air in theffirlher to four m the latter. Find the temperature and degree of saturation in the resulting mixture. Solution a: From the data of Table 2. The only unknown properties are the humidity ratio W, and the enthalpy Aj of the resulting mixture. These may be determined7 from Equation 34. Thus, -- 1 38 CHAPTER 3 1952 Guide - : ~ ; 20.270 - K, 0.003164 - W, 1 h, - 0.668 ~ W,- 0.000630 _ 4 .7 7'7`V -7 V ; from which A, = 16.350 and IF, =: 0.002657. The enthalpy of the final mixture may also be expressed by Equation 28: : A, = A, + /lAaa ' ' . . . ' ' ' ' " . - ' Since it by definition is W:i/W,, Equation 28 may be'rewritten as .: ; : 16.350. = A. + (0:002657/^X A,, At 56 F 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 . it = 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 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 <7, ^ =1 Gi Da_i 4 .- . Scaling the distances on the chart, the required solution to Example 6 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(IF, -- Wi) and the moisture havingitheenthalpy. A. Btu per pound of moisture.:... : . ; . ... ' : An energy balance yields .. : .. ... .77 7 .. .. ' . ' . . ' G,A, + G,(Wt - W\)hw = G,A, ' . -, .; . (35) Example 6: Liquid water chilled to 40 F is injected into.ah air stream initially, at 95 F dry-bulb temperature and 80 F thermodynamic wet-bulb temperature. At what temperature will saturation be reached ? How much water must be evaporated to reach saturation? i Solution a: From the data of Table 2. The solution of Equation 35 for A, yields : A, =,Ak -Pv(W, - Wt)h, !: The initial enthalpy of: the moist air A, miist be found from Equation 8, , 7 A, - A* - (IF* - IF,)A,,* 7 : 22.827 -f ,.40.49 = 43.69 (0.02233 - 0.03673/,) (48.05) ; from which it 0.511. : ' ' j! Hence, A, = 22.827 + 0.511(40.49) . end = 43.52 Btu per lb of dry air' IF, = 0.03673(0.511) - = 0.01877 lb per lb of dry air. . The solution of Equation 35 is : , A, = 43.52 + (IF, - 0.01877) (8.09) By trial aind error, this equation will be satisfied at the temperature 79.8/ F. At this temperature the-humidity ratio IF, is 0.02223. "The weight of water evaporated is therefore 0.02223 - 0.01877 = 0.00346 lb per lb of dry air. '' ' 1 Q G_ W, W77777^77t7 . MOISTURE ADDED =Gtwj-W,) NO HEAT EXCHANGE ACROSS BOUNDARIES AT ENTHALPY h. Fio. 12. Illustration op Addition op Moisture to an Adiabatic Stream 60 CHAPTER 3 ' 1952 Guide Solution b: From the A.S.H.V.E. Chart. Solution of Equation 35 for the ratip (At - ht)/(.W, -- W,) yields h,-ht W,-Wi / (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 psychrometric chart with the value of h* on the pro tractor. Draw; a line parallel to this reference line through the initial point I (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 thB designation given any, process in which the state of moist air is changed from:some initial unsaturated condition to a saturated one with- Fio. 13. Solution of Example 6 on A.S.H.V.E. Psychbometbic Chabt 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'0 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 psychrometric chart 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 2, and is 65.51 F. At this temperature the humidity ratio at saturation and enthalpy at saturation are 0.01350 and 30.45, respectively. The humidity ratio at the initial state is 0.60(0.01882) = 0.01129; the initial enthalpy is 0-60(20.59) + 18.018 = 30.372. The weightpf water Thermodynamics 61 added is therefore 0.01350 -- 0.01129 = 0.00221 lb per lb of dry air; the enthalpy change is 30.45 -- 30.372 = 0.078 Btu per lb of dry air. 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 Stead; Flow Fig. 15 is a schematic representation of a system operating at constant pressure, where ' . Gi is the rate of flow of dry air, pounds per minute. . G, is the rate of evaporation of the water, pounds per minute. h,, 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 1: >1 . OWt + Q _+<?** * GJh . . A mass balance gives , ... (37) Gi + G,Wj + G. = G, + GtW, ' ' GiWi + C. - GtW, (38) L, . * . (Fig. 15. hw, ' ' Illustration of Addition of Heat'and Wateb-VafoS VapoSb to aJr Aib Stream in Steady Flow. 62 CHAPTER 3 i : 1952 Guide ' Combining equations 37 and 38 and solving for the ratio (ht` -- hi)/{W? -- Wi), ht -h W,-Wx Q_ + A, G,, (39) Example 8: Moist air+t 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 flow 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 4.802 + 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,, + M-i + A.*(W* - W.0 = A*. The values of these properties are: A* = 35.39; W* = 0.01668; Aw* = 39.61; A,,i = 90.70; = 0.08149; A., = 28.84. Making the proper substitutions and solving for degree of saturation, " . u = 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. G' = (0-005549 - 0.00172) . \l.\2 -- - . = 6.82 lb per min. The heat supplied is obtained from Equation 37. . Q = Gxilh -- Ai) -- GWA. - = 20,000 (35.02 - 6.65) - 6.32(28.08) . ' = 46,667 Btu per min. .Solution b: From- the -AS.H.V.E. 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, ana read the value of the ratio (At -- hi)/(W, -- H',) as 7500 fronr Thermodynamics 63 the protractor on the chart: (Fig. 16). From Equation 39 ' ' ". " . A, - A, Q . .-. - W1t-W' 1x =.^-+Aw G. = 7500 The rate of water supply was determined in Solution a, but will be found from the . chart. It is ; ' ' ' ' ........ . ' : ; : 20,000 ' G. = (0.0055.-;0,(17) . / ; '' . . . .. = 6.28 lb per min Q ~ Gw(7500 - A.) = 6^8(7500 - 23) .. ' = 46.900 Btu per nun.- . ' , ' ;. Table 6. Pbessube and Temperature for Altitudes in U. 8. : : . Standabd Atmosphebe 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 8^8 7.04 5.54 4.36 3.436 Temp F.; . I. +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 T 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: . 1. There is a linear decrease in temperature T irith altitude up to' the limit of the isothermal atmosphere at 35,332 ft. Thus, .. . .... . T - To - 0.003566' Z :. 2. The air is dry. ' -'. 3. Air is a perfect gas obeying the laws of Charles and Boyle: (40) -. ' ' PV = RT .4. Gravity is constant at all altitudes with the standard value. 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 .1952 Guide Absolute Temperature , Gravity Density ' - : 518.4 F Abs ......... 32.1740 ft per (sec) (sec) , -0.07651 lb per cu ft Values, of pressure and temperature are listed in Table 6 for altitudes in the standard atmosphere from --1000 to`50,000'ft above seiLleyelV ; For further explanation, References 9 and 10 should be consulted. ' ...... LETTER SYMBOLS USED IN CHAPTER 3 a = degree of saturation (decimal), p = density of fluid, pounds per cubic foot. v = relative humidity (decimal). o = 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 usein 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. ' Gt = flow rate of dry air, pounds per minute. -- Gw = rate of evaporation of water, pounds per minute. . H = enthalpy of the system. H = enthalpy of the flowing medium, Btu per pound of dry air- . A = enthalpy of moist air, Btu per pound of dry air. -. - . A = enthalpy correction term to be added above 150 F, to enthalpy. A, = specific enthalpy of dry air, Btu per pound. . A,, = h, -- hm = 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. .. ;- - h2 = enthalpy of saturated water vapor, Btu per pound. . h> = enthalpy of moist air at saturation per pound' of dry air, Btu per pound -- of dry air. , ' -- -- .... hm* = enthalpy of moist air at saturation at thermodynamic wet-bulb temperature, Btu per pound of dry air. " ' 5 - ` - ' : hw ='specific enthalpy of condensed water (liquid or solid) at standard pressure, ' Btu per pound water..; .' . ; . * . Aw* = specific enthalpy of water as added at the thermodynamic wet-bulb fem; perature t*, Btu per pound of dry.air. ' A.i = enthalpy of liquid water, Btu per pound. . ' Aw. = 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. .. <n.= mols of water- vapor at saturation. , nw = mols of water vapor. . P = absolute pressure. ' P. = atmospheric pressure, inches Kg. . ,' Thermodynamics 65 LETTER SYMBOLS (Continued) . P0 f= stsindard atmospheric pressure by definition 29.921 in. Hg. . P. = saturation pressure of pure water at prevailing temperature. p = total pressure of a mixture of air and water vapor, pounds per square inch . . * . or inches Hg. . ... . . .. P. = partial pressure of dry air, pounds per square inch or inches Hg. Pm <= saturation pressure of pure water vapor, pounds per square inch or inches . Hg, . ,. . . .. ' . , p,w,*= .partial pressure of water vapor in mixture of air and water yapor, pounds per square inch or inches Hg. . ..., PE = potential energy, Btu per pound dry air. .. . PE = average potential energy, Btu per pound dry air. Q = total heat added or subtracted, between sections, Btu per minute, q -- ratio of energy added (or removed)-to water added(or removed), Btu per pound. Also called specific enthalpy of water-added. . :. - iqi = energy added between points 1 and 2. ; .. ; iji = heat added between sections 1 and 2, Btu per pound dry air. , B = universal gas constant, 1545 foot-poundAper. (Fahrenheit degree) (mol); = gas constant for dry air.- ' :' A, = gas constant for water vapor. S = flow rate of solid water, pounds per hour. , -. , ; = entropy of moist air per pound of dry air, Btu per (pound)- (Fahrenheit degree). ' V' . ' 8 = correction to be added to entropy of moiBt air obtained from Table 2. i = 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. \ Sm = specific entropy of dry air, Btu per (pound) (Fahrenheit degree, absolute). s,, = the difference between the entropy of moist air a( saturation per pound of dry air, and the specific entropy of the dry air itself, Btu per (pound of dry air) (Fahrenheit degree, absolute). . .. ' s. = entropy of moist air at saturation per pound of dry air, Btu per (pound ' of dry air) (Fahrenheit degree, absolute). . ' ,.... w = 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. : T0 = standard atmospheric temperature, by definition 518.4 F absolute. t = temperature, Fahrenheit degrees. t* = thermodynamic wet-bulb temperature, Fahrenheit degrees. U = internal energy of system. U = internal energy. V = volume. F = average velocity, feet per minute. v -- volume of moist air per pound of dry air, cubic feet per pound. i> = correction to be added to volume of moist air per pound of dry air, above 150 F. = specific volume of dry air, cubic feet per pound. 66 CHAPTER 3 1952 iGuide LETTER SYMBOLS (Concluded) ,, = , -- , 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. . .. pt = total volume, cubic feet. -' < W = humidity ratio, of moist air, pounds of water per pound of dry air. W, = humidity ratio, at saturation, weight of water vapor per pound of dry air, pound per pound. . , W.* = humidity ratio corresponding to thermodynamic wet-bulb temperature i*. pounds of water per pound of dry air. - , w. = work done by system. . . .. . u> <= shaft work withdrawn between sections 1 and 2, Btu per pound of air. Z = elevation above any datum, feet. . 2 = average elevation, feet. Subscripts with symbols have following meanings: 1, 2, 3 indicate section of flow; a = air, w = water, wl = 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). .. * Standardization of Thermodynamic Properties of Moist Air, by J. A. Goff (A.S. H.V.E. Journal Section, Heating, Piping and Air Conditioning, Vol. 21, November 1949, p. 118-128). . . ... ... * The Theory of the Psychrometer, by J. H. Arnold (Physics, Vol. 4, 1933). 4 Thermodynamic Properties of Moist Air, by J. A. Goff and S. Gratch (A.S.H.V.E. Transactions, Vol. 51, 1945, p. 125). 5 Low Pressure Properties of Water in the Range --160 to 212 F, by J. A. Goff and S. Gratch (A.S.H.V.E. Journal Section, Heating, Piping arid Air Conditioning, February 1946). .. Thermodynamic Properties of Steam, by J. H. Keenan and F; G. Keyes (John Wiley and Sons, Inc., New York, 1936). t 7Ein aeues Diagramm fur Dampfluftgemische, by R..Mollier, (ZVDI, Vol. 67, Sept. 8, 1923, p. 869-872). " Das i-x Diagramm fur Dampfluftgemische, by R. Mollier (ZVDI, Vol. 73, July 20, 1929, pp. 1009-1013). ., 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? + Jui + PiVi + Jg 4- -- zi = --- + Jut + prvt + W + -- zj .2g, 9o 2gc (1) where V = velocity in feet per second. 9 = gravitational acceleration, in feet per (second) (second). 9o = 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. 9 = 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, expressed in Btu per pound of fluid, Equation 1 becomes : V,! 9 V,1 g + Jh + Jq + - zi = -r1 + Jh, + W 4- - z, 2ff, gc 2g gc The equivalent differential form for energy Equation 1 is - (2) 1 g' -- dV' + Jdu + d(pv) + -- dz -- Jdq + dW = 0 2ffc Qt ' 67 (3) 68 CHAPTER 4 1952 Guide Replacing v by its equal g/g*p (where p is density in pounds weight per cubic foot) and rearranging, Equation 3 becomes . -- dV1 + - dp + dz +' -- [J du + pdv -- J dq + dW] = 0 2? P 9 . (4) . In the case of flow through a pipe, ho outside work is performed so that dW = 0. Furthermore, ' . y - . 'Jdu + pdv = JTds = J dq + JTda' . ; ' (5) where ," . . - ........ . ds = total change in entropy. . ds' = change in entropy due to internal irreversibility from turbulence and friction.................... . ., .. . . - . . i:. \. ' , ' 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 care 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. . . ... .... ....... : > Fig. 1. Relation of Various Factors in Bernoulli Equation Accordingly, Equation 4 may be written . .. ' -dV' + -- +dz + -JTds'. = .0* - ' " 2g p g " In cases where.there is no internal irreversibility, ds'- may be integrated to give ' : (6) 0, and Equation 6 ^ + - + 21 = ^ + ~ + 2g .pm ... . .2g 2j Pm . (7) where p. is the proper mean density. .. This is commonly called- the Bernoulli equation, named after the Swiss 71 mathematician and physician. who first propounded the theory. ^ is known as the velocity head, - is the pressure head, and * 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 portions of this chapter the distinction between g and ge will be omitted. Aeide from the dimensional consistency the factor, g/ge, is not in general significant in fluid now analysis. Pressure Loss in Circular Pipes . The pressure loss in circular pipes is customarily expressed by the formula: h, flV* 2gd where hi = 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. (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, . ....... (9) 70 CHAPTER 4 1952 Guide where \ .' Nr. = 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 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 Fig. 3. Relation op Kinematic .Viscosity to Temperature of Water 64 / = Nr. (10) With laminar flow, the velocity profile is a parabola, having the formula: . v = ==An - U) 4pl . (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 1 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 Transactions. or glass tubing. The effect of roughness on/, an effect which is considerable at 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 signifyingthe 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 NBe, and from this point proceed horizontally to left margin to find the value of / for use in Equation 8. 72 CHAPTER 4 1952 Guide Theicurves in Fig. 4 may be approximated very closely by'the empirical formula:1 v : <. : ' (12) Equation ;8 is'apjilicable to all 'liquids; and to - gases whfeh the pressure loss is less thaiFlO percent of the initial pressure.-'5.Wheii' the loss in. head .is high, the formula to be used for gases is : 1 e. Pi* -- pi* ' JlVi* - ' iii . . Pf gdPlVl . .. . (13) which may be a to give the loss in pressure; Pi-Pi^PiU-A/^fl : LV ffdpi (14) Fiq. 5. Comparison of Velocity Profiles for 3 Different Reynolds ; ; Numbebs-but fob' Same Average Velocity . Pressure Loss in Non-Circular Pipes The formulas for. friction Joss in piipes.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 d,, defined by the equation: - 4 X area of cross-section r^ 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 = (4 x 2)/6 = l1/, ft. . , In the case of a round pipe, ' 4 X 1V4 J dH (16) . In computing the Reynolds number, and from that the friction factor, the hydraulic diameter is not to be used. A better approximate procedure is to replace the length in the Reynolds number by the shortest dimension plus one-fourth, of the hydraulic diameter. . Thus, in a duct of dimension a x b'where a < b, Nb, for the purposes of calculating friction factors, is ,' 1VK. = (o-f 0.25dH)Vp/M . (17) Fluid Row 73 Table 1.,Vapp^s OF,.e f,or: Different Kinds of Pipe . , : ' IVpe of Pipe' ` / v ' , e . ' Asphalted cast-iron............................... ....... .......... Galvanized iron............................................... ............ Wood stave............. .. _,.......... __________ ................... V-;......' Concrete.............................:.................... 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* + -- = 0 2g p If, in addition, the flow is adiabatic, ' Vp * = pun * so that Equation 18 becomes or by integration, Pillk dp - dV* + .-7- = 0 2g - Pi (18) (19) (20) This extension to compressible flow of Bernoulli's equation reduces to the more familiar form if the pressure change is small. The ratio of specific heats, 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 fob Compressible Fluids COMFHESSIBLE Fl.UII) Ratio k = cp/c-r Helimi! 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. .-....................................... 1.66 1.40 1.34 1.28 to 1.32 1.24 to 1.26 74 CHAPTER 4 1952 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 = kgRTl . . (22) Accordingly, Equation 21 may be written i(Fy - Vy) + 0 (23) or, by rearrangement, k-- Or (24) 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 ' .... so that and ^ = 2* = /^Yr a,5 T, \pj k-1 (w - vy) + ay a,> 0 2 (25) (26) 1 + k - 1 vy ay 2 dy a,' 1 + k ^ 2 1 V, a,*. (27) The ratio of flow velocity to sonic velocity is known as the Mach number, ' M = V/o " '> This parameter is particularly useful in compressible flow analysis. In i general, if M g 0.1 the flow may be considered to be incompressible. This is generally true in heating and ventilating ah'ducts. " In terms of the Mach number ' -. M ay T, a,* ' Ti k-1 i + --My . k-1 i + --My and k--1 i 1 + ~Y~ Ml2 P: Pi i + ^My (29) f. The quantity, Fluid Flow 75 . is called.the stagnation pressure, and gives a measure of pressure energy. For incompressible flow " . . ' where . Tfi = p+~pyt=p+.. g . .2? . , 1 (3i) ,, ' 9 = ^-p?V 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 i -. P = p. \ . : - " ' (33) This represents another extension of the Bernoulli equation to compressible flow. Friction will cause a loss in pressure energy. ' :i ; !,r . > / 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:fiow 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 sepond is to = piA iVi = p?ArVz (34) or, in terms of Mach number, . According to Equation 29 to = AzMt y/kgpzPj i + k- 1 My . 1+SrM*' (35) (36) from which \ .My : (37) so that w -- At k-1 1+-- W i/??t[(S)-] i -.My/My (38) ff the initial velocity is sufficiently small,`Mi1 will be negligible so that P = P (30) If this is computed and. the figures are plotted, the curved1 line (partly akk- ~ - 76 CHAPTER 4 1952 Guide 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: P* . (40) Pi For air, with ft = 1.40, -- = 0.53. P1 . Actually, the broken part of the Curve is not attained for. the flow in the nozzle. If the ratio of pi 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 p/pi is decreased further, the discharge is constant, as indicated by the horizontal line. The value of pi at the maximum point is called the critical pressure, or p,, and it is seen that p0 is approximately 53 percent of pi when air is flowing. Fluid Flow 7.7 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 this case both M, and Mi are small quantities, pi = pi, and (pi -- pi)/pj = Ap/pi is small. Retaining only first order terms, it follows from Equation 35 that . . '' " .' : so that Mi _ Ai ~ Ai (44) 1 - ,'/#?!> VI - {Ai/Axf Vi - P (45) : where ft = D2/Di. The quantity l/\/l -- /34 is the velocity of approach Fio. 6. Relation or Flow or Gas to Pressure Drop in a Converging . Tube ;. To find the velocity at the critical pressure, it is assumed that the J upstream velocity Vi is so small as to be negligible. Using the subscript c to indicate conditions at the critical point, from Equation 29 Pc (41) or Me -- %tt (42) | Substituting the critical pressure ratio from Equation 40 it follows that | ,; M = 1 (43) | or that the velocity at the throat is equal to the local sonic velocity. 1 w. c Fig. 7. Dimensions and Flow 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 2k *--1 . f46) . and-the mass flow is A, w= vr ; y/2gpAp (47) The volume flow is then Q~At vr^ V2?Ap/p=A* (48) 78 CHAPTER 4 1952'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 Meiers (Pressure Sensitive), which may be of Venturi, flow nozzle, orifice plate, or Pitot, tube types; (2) Area Meiers, which may be of gale, tapered tube, or tapered plug types; (3) Force Meters, which may be of vane, propeller, or turbine types; (4) Quantity Meters, 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 Note: From Table 6 of Reference 2. 79 Fig. 8. Dimensions fob International Standards Association Flow Nozzle . Note: From Reference 3. Used by permission of AJ5M.E. 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. Flow Coefficients, K for Square-edged Orifice Plates and Radius :' . . - Taps in Smooth Pipe ' 1 : Note: From Fig. 36d of Reference 4. ' ' ' ' '10- 11- Flow Coefficients, K, for Square-edged Orifice Plates and Vena Contracta Taps, in Smooth Pipe Note: From Table 7 of Reference 2. 80 , , CHAPTER 4 1952 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 = yr--^ V 2ffpAp (49) Fluid Row 81 and .......................... Q = KA, >/2ght (53) The coefficients K and C will be determined by the area ratio Aj/Aj, or by the diameter ratio Di/Dj 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 Vr,, the Reynolds number, and the ratio of diameter, of the orifice or nozzle throat tcf 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 Nozzle as a Function of Area Ratio (D,/Di)! and the Reynolds Number Nut Note: From Reference 3. Used by permission of A.S.M.B. and '' ..... - - AjC ,______ (50) 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 Ai/A2,it is often convenient to introduce a combined flow coefficient, K which is . '. ' ' C . K = vr^ (51) so that ' to = KAt\/2gf>&p (52) < >,Fig. 13. Relation of Expansion Factor, f 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. 4 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 <f> the equation for flow with no loss becomes: Aj0 . w = VT-a* - p>) (54) By comparison with Equation 35. = /k 1 - ffl) * r 2 p, (p,/p,) - l From Equations 34 and 35, (55) . = (P(pt/pi),,k (56) 82 ' CHAPTER 4 - Hence, by Equation 38 for a small value of Mh 1952 Guide i .y U- - 1/ (pi/p.) -1 i ->(Pi/pl)" From Equations 37 and 56, if M2 is not too large; ; ' '' r ' ' iM%l -&-'$&* ' so that, approximately,; ; ; . ; 1 - If1 + (` - f)^] ^ '57 " (58) (59)' " Fluid'Flow 83 Installation of Head Meters : . i, . - 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 contracts 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- < >,Fig. .14. Relation of Expansion Factob, t fob Nozzles to Diameteb Ratio and Pbessube Loss fob Steam, Cabbon Dioxide and' NatubAl ,Gas Where to the same degree of approxiniation from'Equation 36 . ' ' `' `' ,Pi - Pj M2 = 2- kjh ' ; (60) Values of <f> 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 <t> by an empirical factor Y obtained by the,equation ., =Y 1 - (0.41 + O.350`) (61) When this correction is used, the flow will be given by the equation .. , . to = KAiY y/2jpi(pi - pj) (62) Fig. 15. Minimum Conditions to be Obsebved When Installing Obifices 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 corner tap, is used in . European practice. Pressures are taken from recesses in the flange connected to annular slits in the comers formed by the pipe wall and the orifice plate. 84 . CHAPTER 4 1952 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 contracts-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 Fc from, Equation 64, .. , ' F,, = 1 + \M' + AM' - ' ; * (64)' where .> M> = 2 kp- . , (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 am 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 of 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 49). 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 = s/zghi (63) Fig. 17. Location of Vena Contracta in Relation-to Ratio of Orifice to Pipe Diameter and to Rate of 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- 1952 Guide formed bestween the float mid inside wall of the tube'. :At'any particularrate 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, vt(pi -- p), is balanced by the pressure difference acting on the cross-section area of the float, A fAp, where pt, A;, vf, are, respectively, the float density, float cross-section area, and'float;volume; ' Accordingly, the difference in head across' the annulus is.given by ` : - "-ii: Fig, 18.. Schematic Diagram op Variable Area Flow-Meter i The.voluxne.flow.follows from equation (63) as ........................... ... . t .... . - ; . .... . Q =. KAt\/2ffPf(prfi)/pAj .:............- , (67) and the mass flow as j ... w = pQ -- KAt\/`2.<jvt(pi -- p)-p/Ai ' - {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 investigated* and; |the ac tion .of the flow-meter as just outlined, experimentally .confirmed. The, flow-coefficient variation for any. float must be known in older tq 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 - f} -- ratio, throat or orifice diameter to pipe diameter. - , . (i = absolute viscosity, pounds per foot second. , . . , n/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). .' pr = density of float in variable area meters. $ = expansion factor for nozzles. - ' a = velocity of sound, feet per second. ' A =. cross-sectional area of flow, square feet.. . . ... C = correction' factor (coefficient of discharge) for flow through orifice, nozzle or Venturi. ' . , Cp = specific heat of gas at constant pressure. e*-= 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). .' gt = 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. . At = 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 Venturi. . k -- ratio of specific beat at constant pressure to specific heat at constant vpl- ume. . L = perpendicular distance from axis of pipe, feet. .. I = length of pipe, feet. : . . - M = Mach number. . . , . NR* = Reynolds number. . - p =,pressure, pounds per square foot. p = stagnation pressure. .. .. . .- . . . . ., pc = critical pressure. - Q -- discharge rate, cubic feet per second. 0 = heat transferred to the fluid per pound of fluid flowing. R -- gas constant. ' . r = 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. Fc = critical velocity, feet per second. v = specific volume, cubic feet per pound. . W = mechanical work, foot pounds per pound of fluid flowing. w = mass flow of gas, pounds per second. Y = expansion factor--correcting for expansion of gas under reduced down stream pressure. . z = elevation above some arbitrary datum, feet. REFERENCES 1 Friction Factors for Pipe Flow, by Lewis F. Moody (A.S.M.E. Transactions, 66, 1944, 671-678; Discussion, idem. 66, 1944 , 678-684); also, An Approximate Formula for Pipe Friction Factors (Mechanical Engineering, 69, 1947, 100S-1006). 1 88 , .CHAPTER 4 1952 Guide . * Fluid Meters, Their Theory and Application (American Society of Mechanical Engineers, 4th Edition, 1937). . 1 Flow Measurement, Power Test Codes, Part 5, Chap. 4 (American Society of Me chanical Engineers, 1949). - Standards for Discharge Measurement (National Advisory Committee for Aero nautics, NACA Tech. Mem. 952, 1940) (Translation of German Industrial Standard 1932). .. 5 Gas Measurement Committee Report No. 2, Natural Gas Department (Amer ican Gas Association, 1948). The Flow Mechanism and Performance of the Rotameter, by E. M. Schoenbom, Jr. and A. P. Colburn (Institute of Chemical Engineers, Transactions, 35, 1939, 359 381). . - BIBLIOGRAPHY . [A] Thermodynamics, by Edwaid F. Obert (McGraw-Hill Book Company, 1948). [B] Thermodynamics of Fluid Flow, by Newman A. Hall (Prentice-Hall, Inc., 1951). [C] Fluid Mechanics, by Russell A. Dodge and Milton J. Thompson (McGraw- Hill Book Co., 1937). . [D] Fluid Mechanics, 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. Prandtl (Blackie, 1936). .. . . . [F] A Study of the Data on the Flow of Fluids in Pipes, by Emory Kemler, Hy draulic Paper HYD-55-2 (A.S.M.E. Transactions 65, No. 10, 7-22, 1933; Discussion, idem., 55, No. 10, 23-32, 1933). [G] The Flow of Fluids in Closed Conduits, by R. J. S. Pigott (Mechanical Engi neering 65, 1933, 497-501, 515). . [H] Fluid Meters, Their Selection and Installation (American Society of Mechanical Engineers, 1933). ." (H The Orifice 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 67,1935, .281 294; Discussion, idem. 58, 1936, 146-156). [Kj Pitot Tubes in Large Pipes, by Edward 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.S.M.E. Transactions, 67, 345-357, 1945; Discussion, idem. 67, 357-360, 1945). CHAPTER 5 HEAT TRANSFER Conduction, Convection, Radiation; Equations for Conduction, Convection, 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 34. The objectives of this chapter are to: 1. Describe the mechanisms and present the rate equations for the different modes of heat transfer. . 1 2. Rlustrate 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 m 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 mvolves 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 U to a colder fluid at a bulk tem perature ti. (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.) jin the laminar sublayer, immediately adjacent to the wall, the. heat. transfer <furs by thermal, .conduction; in the transition region,' which is`l called the, buffer layer, eddy mixing as well as conduction effects are significant; 89 ' 90 CHAPTER 5 1952 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. '. ...Im the conduction and convection mechanisms, the transfer of heat is associated with matter. For: radiant heat transfer, however, a change in laminar region "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 squarefoot 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 try 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.: Fiq. 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- ariisms 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 (teiri1 ' peratiire difference) and a resistance in order that heat transfer calculations Jr may be effected more conveniently and rapidly. f 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). . " . 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 y the physical significance of the indicated quantities; * . Tt should be emphasized that the thermal conductivity used should be ^ expressed in consistent units; either using the inch or foot throughout. ' ^ . ............... Fiq. 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 feet. -. ... Thermal Convection Equation ' = h,,(t. - t,) 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- Table 1. Approximate Unit Thermal Conductivities* . Conductivity, k = Btu per (hr) (sqft):(F deg per in.) Material . *; .. Material . *: Air......................... Aluminum............. Brass (70. - 30).! Cast-Iron........ Copper. ........ vrlass.................. .. 0.168 1416.0 720.0 336.0 2640.0 3.6-7.32 Nickel................. .............. SoU......................... Steel , mild.......... . Water, liquid........ ........ ! 240.0 408.0 . ... 2.4-12.0 312.0 4:08 ' I^crtnal conductivities depend to some extent on temperature. The'above magnitudes are apprcsiTMate only. Refs to Chapter 9, and Reference 4 for additional data. 92. ,, CHAPTER S 1952 Guido perature difference (i, -- if) 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), hc, 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 values* 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 of natural convection may be solved by the simple first-power equation if the convection coefficient is expressed as a unit conductance: q = K- A (ti -- h) (2b) where heat transmission by convection, Btu per hour, surface area, square feet. temperature difference between the Burface and the fluid, Fahrenheit degrees. . 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- jr = itAiFaFe (Ti4 -- 7Vl (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, qj A Btu per (hour) (square foot), which sees surface 2 through a non-absorbing medium, is proportional to the difference of the Heat Transfer 93 .Table 2. Approximate: Unitj.Conductances -fob. Thermal Convection fob 1 Several Flow.Systems ... Expressed in Convenient Empirical Form M , . CHAPTER 5 . L952 Gufdfe -'Table. 2. 'Approximate Unit Conductances fobThermal Convection ifob Several Flow Systems (Concluded) Case ; - - System ' * Heat Transfer Equation* and its'Limits of Application RepebENCB " : : * Forced Convection ' 9 Same aa Case 7. ! ' General Equation (Laminar-Flow) 3- 10 Same as Case 7. ; For .600JB00.'-' . 4c (tnrag*) " 2hex 'Equation for Air * Flow) ' 1c = 0B562(rf)M ' ' 3 For < 500,000 Fbeb Convection0 11 # Equation for Air . * <$r*- (kT io> < nGi < io' 5 Free convection past a heated horizontal cylinder. ', 12 T| Equation far Air ................ e i iJ ! l0*-< JVGr < 10' Free convection pa it a single vertical sur- . face. ., 13 i JV. U t --J Free convection past a heated horizontal surface (face up). 14 i ' t*-- <~~i 1 ,' 10* < NGt < 10" Equation for Air *.-("()"* 10* < Nqt < 10T 5 Equation for Air ("(fr 10* < Nqt <10* -6 Free convection past a heated horizontal : surface .(face .down). \ : . ' a Fluid properties should be evaluated at the arithmetic mean fluid temperature, ff. = ,(t surface + t fluid) divide^ by 2. ' ' ' .. '';* , * -c . . t. o These expressions are suitable approximations to longitudinal flow m other than nght circular cylinders, provided the hydraulic dtnmptp.r is employed as the conduit dimension parameter. . For non-circular cross sections, the hydraulic is equal to four times the cross-sectional area divided by the wetted perim eter. ... ' For low rates of heat transfer by free convection the exponent decreases towards zero, and for higher rates, increases towards 0.33. The above equations employing an exponent equal to 0.25 are applicable in the intermediate range indicated. ' ; NOMENCLATURE AND DIMENSIONS FOR TABLE 2 cp = heat capacity at constant pressure, Btu per (pound) (Fahrenheit degree). D = cylinder diameter, feet. / = 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 3600* feet per hour per hour.) G 3600 Ump = mass flow per unit'cross-sectional area normal to flow, pounds per (hour) (square foot of flow cross-section). . jVisr = Grashof modulus, dimensionless (Na'r = D'p'p^ig/pf). he = average unit thermal convective conductance from the leading edge of surface to the position i, Btu per (hour) (square foot) (Fahrenheit degree). AC1 = 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). - ............ I = a dimension of the system, feet. \ . . m = a subscript denoting mean. :i P = pressure, atmospheres. -- Pa = pressure (atmospheric) atmospheres. ' . t = temperature, Fahrenheit. T = temperature, Fahrenheit, absolute. . it = fluid.velocity, feet per second. . ' ' ' , V V = volume, cubic feet. '. '; . '. . x = a dimension of the system, feet. ... 1 dV p = coefficient of cubical expansion (p =: ^(^y)p); for.perfect gases (3 = 1/T. At'= 'difference between wall and .fluid, temperatures, Fahrenheit degrees. : - p = fluid viscosity, pounds,per (hour) (foot). ... .. .. ; p = density, pounds per cubic foot. , . . . .. > . oo = infinity, referring the quantity to a point not directly affected by the phenomenon in question. : Table 3. . Radiation Factors or Emissivities. c* :` For the determination of factor FE :in Equation 8" ' Class Subpaces Fraction op Black-Body . . , Radiation ; r At 50-100 F At 1000 F Absorptivity -- (FOB t: Solar" * Radiation 1 . A 8mall hole in a large box, sphere, furnace, or enclosure.................... ........................................................ 0.97 to 6.99 2 -Black non-metallic surfaces such as' asphalt, car- ' bon, slate, paint, paper............... .......................... .... 0.90 to 0.98 3 Red brick and tile, concrete and stone, rusty steel and iron, dark paints (red, brown, green, etc.).. 0.85 to 0.95 4 Yellow and buff brick and stone*, firebrick, fire clay........................................................................................ 0.85 to 0.95 . 5 White or light-cream brick, tile, paint or paper. 0.85 to 0.95 6 0.90 to 0.95 7 -8 Bright aluminum paint; gilt or bronze paint___ *. 0.40 to 0.60 Dull brass, copper, or aluminum; galvanized steel; polished iron.......................................................... 0.20 to 0.30 9 Polished brass, copper, monel metal.......................... 0.02 to 0.05 10 Highly polished aluminum, tin plate, nickel, chromium ........................................................... . 0.02 to 0.04 0.97 to 0.99. 0.90 to 6.98 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.S5to0.9S 0.65 to 0.80 0.50 to 0.70 0.30 to0.5i> Transparent* 0.30 to 0.50 0.40 to 0.65; ,0.30 to 0.50" 0.10 to 6.40 Emissivities of other materials may be found iu Reference 4. " Reflects about 8 percent. fourth powers of the absolute surface temperatures (7Y -- T*4). The pro portionality factor (oFaFe) 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-" Btu per (hour) ` (square foot) (Fahrenheit degree absolute temperature to the fourth power). "a =' the geometrical factor which is dimensionless and S 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 and 1. This factor ac counts for the absorption and emission characteristics of the surfaces for the 96 , CHAPTER 5 ; 1952 Guide 3.Fig. Radiation Between Surfaces . radiation which exists. Emissivities or absorptivities () for many common surfaces, are given in Table 3. The value of Fb for large parallel planes, long concentric cylinders, or large enclosed bodies is 1 .+ (1/ei + l/ -- 1).` - The radiation under black-body conditions, or for an-emissivity of 1.0, is given in Table 4a for cold surfaces as low. as --39 F to warmer 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 7). . Photographic and other methods are given in References 8 and 9. - 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 radiation by the equation: 5, = A, A (ti - tj) . (4) TAble 4. Heat Transmission by Radiation for Black-Body Conditions* ' Expressed in Btu per (square foot) (hour) . Temp `F - Deo 6 -1 -2 -3 -4 -5 -6 -7 -8 -9 -30 -20 -10 0 59.3 65.2 71.4 78.0 .58.7 64.7 70.8 77.4 58.2 64.1 70.1 76.7 57.7 63.5 69.5 76.0 57.2 62.9 68.9 75.4 56.7 62.3 68.3 74.7 56.2 61.7 87.7 74.0 55.7 61.1 67.1 73.4 55.2 60.5 66.4 72.7 54:7 59.9 65.8 72.1 0 0 . 78.0 10 ' 85.0 20 .92.4 30 100 .40 . 109 50 118 60 127 70 137 80 148 90 159 " 100 170': 110 183 120 196 - 130 211 -H 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 +3 80.1 87.2 94.8 103 112 121 130 140 151 162 174 187 200 215 +4 80.8 88.0 95.6 104 112 122 131 142 152 163 175 188 201 217 +5 81.5 88.7 96.4 105 113 123 132 143 153 164 176 189 203 218 +6 82.2 89.4 97.2 105 114 123 133 144 154 166 178 191 204 220 +7 82.9 90.2 98.0 106 115 124 134 145 155 167 179 192206 221 +8 83.6 90.9 98.8 107 116 125 135 ' 146 156 168 180 193 207 222 +9 - 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 9 (102 -- 62.3) 0.95 37.7 Btu per (square foot) (hour). Heat Transfer 97 - Table 5. - Net Radiation Solutions System > > Solution ' . Remarks Two infinite parallel planes. e, e3 ^2 el*e2: 7 J--------"(TV - TV) Considering interrefiections. iA 1+ -Cl -i (Reference 5). _\ ^ G)L+L/(ri' Considering interrefiections. m (References)' ' o _ One radiation shield between two infinite parallel planes. 9r` 1 /9r\ .A . n + 1\A/p_ . Considering interrefiections. (Reference 5) . _ ere23 *^1 .. where the net radiation ex n radiation shields between two infinite parallel planes. - - change without the shields'. T = -j----- --r^TT---------Trt . . ei it\e / - . Considering interrefiections and diffuse surfaces. (Ref erence 5)- Two concentric spheres or'two infinitely . lon cylinders. - ~ = n <wFa<7V - TV) dAi. . Surface diffuse, neglecting interreflection. (Refer ence 5) Two areas dAi an d dAi - : *OI*1 = G) Neglecting inteireflections. - T*\ (Reference 5) ' where N is the length of cylinder from which Qr is exchanged - Tube of infinite length parallel to an in finite wall. . -)T - Surfacesare perfect radi- 4T~ / atore. . =, See-Fig. ,4* ' .. . - ' (Reference 4) ' ' Surface element di and rectangle above and parallel to it, with one corner of reot&ngle contained in normal to dAi - ij. - Surfaces are ` perfect 'ra- ` - . See Fig. 5 ' (Reference 4) rTv ' diatore. ' ^'planes1 rec^anK^es in perpendicular Surfaces are perfect ra diators. . -See Fig. '6' (Reference 4) Oppostid parallel rectangles and di^ks of equa1 size. . . - ' '' 98 CHAPTER S 1952 Guide Heat Transfer V '99 - The conductance hT thus defined is a function of the shape-eniissivity factor, as .well as the temperatures of the radiator and receiver. - Fig: 7 shows a plot of the equivalent conductance for two black bodies (t.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 cases it is durable to treat convection and radiation as a single combined process, using a first-power equation: . Vr *= h,, A (t, - t,) . (5) where qTc is the total heat flow due to radiation and convection, in Btu per hour: Values of Arc, the surface or film conductance for combined Fio. 5. .' FGeometrical Factor for Direct Radiation Between Adjacent Rectangles in Perpendicular Planes* Fig. 6. PGeometrical Factor for Direct Radiation Between Opposed Parallel Rectangle and Discs of Equal Size* *Fiom Radiant Heat Transmission, by H. C. Hottel (Mechanical Engineering, July 1930, pp. 700 to 702). Pig. 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 !v In most of the steady-state heat transfer problems encountered in`air conditioning applications, more than one of the heat transfer mechanisms ' fira effective) and the thermal current'flows through several resistances in senes or in parallel. In using the resistance concept, the calculations inf volved are analogous to the application of Ohm's Law in electricity, viz:, "fie heat flow or thermal , current is directly proportional to the thermal Potential or temperature difference, and inversely' proportional' to the thermal resistance: ' . . '' nj -- R 100 CHAPTER 5 1952 Guide Following the-electrical analogy, when there is a thermal current-flowing through several resistances in series, the resistances are additive: ; ' fiT = Ri + R + Rt + -I" tt, - (7) Similarly, conductance is the reciprocal of resistance, and for heat-flow through several resistances in parallel, the conductances are additive: 11 1 ------- 1-----------1-------- h R, Ri Rz (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, 27 and 35, 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 Heat Transfer 101 Table 6. Solutions.for Some Steady-State'Thermal Conduction. Problems8- b No. Systsm Expressions for the resbtaace.lt entering Into the conation: * -- . . . ' ! tl/R (Btu per hour) - ; l. Flat wall or curved wall if curvature is small (wall thickness less than 0.1 of inside dia meter). . o . Jl - 7 kA Surfsce are^A Radial flow through a right circular cylinder, ' "tot : UngcyGndtr ollereaN r.ij'fcj R- -- 2wklf (See footnote *), R~ / txtN ~ tsm Fo* y 3, a satisfactory approximation b: iox*-p co*b-> --* 2tMH " Fig. 8. Heat Transfer Conditions in an Insulated Cold- Water Line steady-state' conductionproblems.. 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, ' <?rc, Btu per hour, may be thought of as flowing through the parallel _ resistances Rr 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, R- r# 4rfc The straight fin or rod baated at one end. . . * U Conduction 1 cross-section ^reaiA ' Finned surface of area BB. \jpi * " *.tanhL Creefootnote.<(tnd. For ml > 2.3, tanh n 1 m -- yfksP/kA . A -- conduction cross-section area* P -- perimeter of cross section A. As " unit conductance to the surroundings from the fin surface. -' k -- thermal conductivity fin material. ' 6S -- wall temperature--ambieat temperature (* 4 O R rn A. (-J-taohM-1) BB n - JisE _ J?-*! JfcA y U 61 defined as In Case $ above. Btu Se/k"l"won8 to eJn^yed m these solutions are: length of dimension p, L, t = feet: units of k - fom)nLffi!uS Wuare foot) (Fahrenheit degree for one foot thickness); units of h, Btu per (hour) (square ^ iranrenheit degree); units of area. A = square feet. e thermal conductivity, k, in these solutions should be taken at the average material temperature. ^ loge * = 2.303 logic s. * Dlovi^3 exPression can also be employed as an approximation for tapered fins or of annular fins by em- average magnitudes of A and p. * tanh is the hyperbolic tangent. n 102 CHAPTER 5 1952 Gaide Rti.and into the water stream 'through tho convection resistance, ..R\, Note tiie 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 JBtu, is the summation of the individual resistances: .; '. - . - ; : .; Rt -- Ri + Rt 4- Ri -\-. Rt ' ' ; (9) where the resultant parallel resistance Ri is obtained from: f . - ' li i i F= . : ,, .do) 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: '. \ (to - t,) g,, (Btu per hour) = . Rj> (11) For a unit length of the pipe the heat transfer rate is: '. 77 Btu per (hour) (foot) - ^~rr~ ........ N '; fS-rly;. - (12) The temperature,drop, At, through an individual resistance may then be calculated from the relation: ' ' ' .... . .. , At -- R q,, (13) where R is the resistance, in question. it . -' 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 9 ~R (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 Rt and Rt, is case 2 in Table 6. Thus for a 1 ft length of 2 in. nominal sizb 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 log, Ri = 2ir X 1.033 26 X 1 = 8.5 X 10-4 (hr) (F deg) per Btu. 2.188 log. 11 .18S8 R, = ------------ :--------- = 3.9 (hr) (F deg) per Btu.. . 2ir X 0.025 X J .; . Heat Transfer 103 The convection resistances to heat transfer from the .pipe wall to the cold-Water, iZi, and from thb air to the surface of the insulating1 material; Rt, 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 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, ft. 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. i.,!- 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 (fallowing:-; \ .... . <> K = 13.9(l<)-==' ... .- Ur* " ' ' A r<v '' : ' (15) . where Ua = 5 fp8 2.067 D 12 0.1725 ft .i - 34 + 36 U= 2 35F _ m Blu p,, ,p j.g,.........., This heat transfer rate is through the inner surface of. the pipe and it is, therefore, this area that determines the resistance Ri- :' ^d therefore A = *D = 0.542 sq ft per unit length of pipe, Ri ,1 . hcA 494 X 0.512 Rt = 3.73 X 10'* (hr) (F deg) per Btu.'. n 104 CHAPTER 5 1952; 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.this case is as follows: / >\.-7aA- ft, = 0271 (16) where therefore, Af = 20:F' :\ : ' '.D = 0.364 ft : ' P ;= Po = one atmosphere .... .. - . ft, = 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 = jt x 1 = i-14 s<ift ; R, _L 1. KA ' 0.737 XU4. jR, = 1.19 (hr) (F deg) per Btu. This result" may not be deemed conservative inasmuch as the expression is for stillair.- 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. (tt.p)0'* ftcOven*.) = 0.211(T,) D* (17). 100 + 120 T, = 4- 460 = 570 Rankine (Fahrenheit abstract) u. = 7 fps ' ". p = 0.076 = 0-06911*5 per cu i) = 0.364 ft 0.211(570) (7:X 0.0694)-* .. ft,(.TMW) - (0.364)-* ftc<v,,v) = 2.73 Btu per (hr) (sq ft) (F deg) and 11 Rc (Forced Convection) = ft, A 2.73 X 1.14 Rc = 0.321 (hr) (F-deg) per Btu. . The radiation resistance, Rr, which acts in parallel with the resistance just calculated, can be computed with the aid of Fig. 7. The pipe wall, . assumed 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 ~gr is determined directly. .. . f r E . .. *; p^j?E = 14 Btu per (hr) (F deg) (sq ft). The angle factor:, FAl is unity, and for an estimated surface emissivity of 0.95 (see Table 3),. FE == ,0.95. Therefore, , .. ft, = 1.4 F*F = 1.4 X 1 X 0.95 : ft, = 1.33 Btu per (hr) (F deg) (sq ft) and the radiation resistance, Rt, is then the following: : hr A 1.33 X 1.14 i ' 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 A R< L 'i_ Rc + Rr 5^ :+ 0^9 = iM Btu per (hr) (F deg) Rr = 0.216 (hr) (F deg) per Btu. ' 5 - " !/ ' The overall resistance, Rt, surroundings to cold water, is the stun of Ri + Rt + Ri + Rt -- 4.12 (hr) (F deg) per Btu for 1 ft length of pipe. Note that the controlling resistances are Rs and Rt, and that neglect of both Ri and Rj would not significantly influence the total-resistance, Rt. On the basis oif this resistance calculation* the heat transfer from the surroundings to the cold water may be evaluated as: ; Ore _ to tl 120-34 N~ Rt = 20.8 Btu per (hr) (ft) 4.12 or about 0.175 tons of refrigeration per 100 ft of pipe. Since the calculation is based on a 1 -ft pipe length: - - - .. . =. 20.8 Btu per hr. . The temperature drops through the various resistances are now readily evaluated by Equation 14 as:. . . - . At = qR . to -- t,, (air to insulation surface) = qR, = 20.8 X 0.216 = 4.49 F deg ta -- la (through the insulation) = qR, = 20.8 X 3.9 = 81.2 F deg - tn -- (,i (through the pipe wall) = qR, = 20.8 X 8.5 X 10"* = 0.018 F deg ti -- t, (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 fiitially made. It is apparent that a better solution could be obtained if the whole problem were reiterated using the temperature distribution just ^lculated. : .. 106 CHAPTER S 1952 Guide r 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.4-6'9-10'11 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 Fro. 9. . Example op a Graphical Solution to a Pboblem in Transient Heat .. _ Conduction. . ' summary of the cases reported and tabulated. Many more analytical solutions are available in the form of infinite series,10'u-17-18 but are not tabulated. Certain complex cases may be treated by combining the simple analytical solutions as discussed in Reference 16. (See also Reference 24). 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.4-9-18-19-20 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,6-19 and also, for one dimensional (radial) heat flow in spheres and cylinders.20-23 Heat Transfer 107 Table 7. Analytical Solutions por Heat Conduction in Variously Shaped Solids . Shape .op Solid . Boundabt Conditions Data Available in Graphs Semi-infinite. Surface temperature changed. suddenly - Temperature distribution in solid as a function of time. ' References: (4) p. 37, (6) p. V-28; (0) p. 254; (12) p. 45. *3--*- . x-- ' A steady flow of heat is suddenly ap plied to the surface. Heat flow from surface as a function of time. References: (0) pp. 256,267; (12)p.47. Temperature distribution as a func tion of time. - Reference: (9) p. 257. The surface temperature has been Temperature distribution as a func varying sinusoidally with time for tion of time. a long time. - Reference: (9) p. 296. ; Heet flow from surface as a function of time. - Reference: (9) p. 296. Semi-infii ite with fluid at Hie temperature of the fluid in con free sux ace. - - tact with the surface has a sudden change in temperature. (The sur face conductance is constant). Temperature distribution as a func tion of time. ' References: (4) p.37; (5) pp. V-45,48, 1) V?- M ^ | ~ " The temperature of the fluid in con tact with the surface has been vary ing sinusoidally with time for a long time. (The surface conductonce is constant). Temperature distribution as a func tion of time. Reference: (9) p. 298. Heat flow from the surface as a func tion of timeii . Reference: (9) p. 298 Slab. k The temperatures tx and are sud denly changed from the initial uni form slab temperature to a new temperature. (The case where the surface on one aide is is treated by 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. . References: (5) p. V-12; (9) p.265. The temperature h and b suddenly begin to inoease as linear func tions of time. The- slab is in itially at uniform temperature. (The ease where one surface is against heat flow is treated as noted above). Temperature distribution aa a func tion of time. - - Reference: (9) p. 268. The temperature at both surfaces Temperature distribution as a func has been varying gmunid*lly for a tion of time. ' long time. Reference: (9) p. 300. . Heat flow from the surface. Reference (9) p. 303. . 8l&b imm.Breed ixi a fluid with constan t cone uetance between fl aidan< 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). Temperature distribution aa a func tion of time. References: (4) pp. 32,33, 34,85; (5) pp. V-9,10,35, 42; (9) pp. 274,284; (12) p. 106. % Heat flow from the surface aa a func tion of time. . References: (5) p. V-10; (9) p. 274; (12) p. 107. 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 temperature are expressible as a Fourier series). Temperature distribution as a func tion of time. Reference 13. Heat flow at the surface as a function of time. ' Reference 13. 108 CHAPTER 5 1952 Guide Table 7. Analytical Solutions fob Heat Conduction in Variously Shaped , Solids (Concluded). Shape op Solid Boundabt Conditions ' Data Available m Gbaths Cylinder of infinite mension di The surface temperature is suddenly Temperature distribution as a func . changed from the initial (uniform) tion of time. temperature. Reference: (9) p. 265. Heat flow from surface as a function of time. Multiply temperature difference be tween surface and fluid by surface . conductance. The surface temperature suddenly Temperature distribution as a func begins to increase linearly with tion of time. time. - Reference: (9) p. 269. Cylinder of ipfinito ami di mension immersed in & fluid. - ft* The surrounding fluid suddenly changes from the initial (uniform) temperature of the cylinder. Temperature distribution as a func tion of time. - References: (4) p. 36; (5) pp. V-16, V-35, V-43, V-48; (9) pp. 278, 286; (14). Heat flow from the surface as a func tion of time. .. References. (5) p. V-16; (9) p. 278. The temperature of the surrounding Temperature distribution as a func fluid ohanges sinusoidally. tion of time. - Reference: (5) p. VI-34. . - Heat flow from the surface as a funotionof time. . Reference: (6) p. VI-36. Sphere 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; (9) pp. 264 265. The temperature at the surface sud Temperature distribution' as a func denly begins to change as a linear tion of time. . ` function of time. Reference: (9) p. 269. Sphere immersed in fluid. The temperature of the surrounding Temperature distribution'as a func fluid suddenly changes from the tion of time. initial uniform sphere temperature. References: (4) p. 36; (5) pp. V-21, V-35. V-44; (9) pp. 281, 282; (4). Heat flow as a function of time. References: (5) p. V-21; (9) p. 281. Rectangular bar of infinite length. Any of the above noted boundaryconditions for a slab. Temperature distribution as a func tion of time. Combine solutions as indicated in Refs. 15 and 16. Parallelopiped (rectangular). Any of the above noted boundary conditions for a slab. Temperature distribution as a func tion of time. Combine solutions as indicated in . Refs. 15 and 16. ' Cylinder of finite length. Any of the boundary conditions given above for a cylinder and a slab. - Temperature distribution as a func tion of time. ' Combine solutions as indicated in Refs. 15 and 16 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- in Refs. 15 and 16. Heat flow at the surface as a func tion of time. Reference: (9) p. 267. Consider the slab to be divided, as shown in Fig. 9, by n equidistant planes parallel to the slab surface and a distance Ax apart. Let the tem perature of the slab at any plane and any time (0) be denoted by Then the temperature of the Blab at the two adjacent planes at the same Heat Transfer 109 time will, be denoted as Tli+Az.e) and T(z~Az,$y. - In a similar manner the temperature of the x plane at a time A8 later will be T<i,*+(A). In accordance with this nomenclature, the temperature at any plane x and time 8 + A0 is given as /(x+Az.S) + T{x--Ax,d) T{x.e+A)'= --------- ;---------------------- (18) which may be interpreted as follows. The temperature of the slab at any plane, x, and any. time, 8, is equal to the average temperature of the two adjacent planes obtained at the time (8 -- A8). ' The time interval A0 i determined by the equation 2Az* ae = -- a (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 ar* ' . h(Ta- T) = -k --OX In terms of finite differences these two equations (employing nomenclature established by Fig. 9) become . and ------- -- =0 or Tf = Te at x = L . Az . . or KT,, - Ta-) = -k (7'B ~- 7'a) at x = 0 . Az = _ Tk TT ~ Th' ~b . k/h Az . 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 litera ture.5-91118 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 1952 Guide the analogy of electrical resistance-capacitance networks to thermal systems.11 , . For two dimensional problems in steady state conduction, additional techniques of solution are found in flux plotting,5'18 and in the use of a potential tank.5,18 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). I The Transmission of Heat by Radiation and Convection, by Griffith and Davie (Special Report No. 9, 1933, Department of Scientific and Industrial Research. Hie Majesty's Stationery Office, London, England). ' A Method of Correlating Forced Convection Heat Transfer Data and a Compari son with Fluid Friction, by A. P. Colburn (American Institute of Chemical Engineers Transactions, Vol. 29,1933, p. 174). . . 4 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). . . Heat Transfer by Free Convection from Heated Vertical Surfaces, by V. S. Touloukian, G. A. Hawkins and M. Ja'ckob (A.S.M.E. Transactions, 1948 p. 13). 7 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). ' Heat Transfer, by Max Jakob (John Wiley and Sons, Inc., Vol. 1,1949). 10 Numerical Methods in Engineering, by L. E. Grinter (The MacMillan Co. 1949). II Numerical Analysis of Heat Flow, by G. M. Dusinberre (McGraw-Hill Book Co., Inc., 1949). . 17 Elements of Heal Transfer and Insulation, by Max Jakob (John Wiley and Sons, Inc., 1942). ', 18 Periodic Heat Transfer at the Inner Surface of a Homogeneous Wall, by H. A. Johnson (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, May 1948, p. 121). 14 Temperature Charts for Induction and Constant Temperature Heating, by M. P. Heisler (A.S.M.E. Transactions, Vol. 69, 1947, p. 227). 14 Temperatures in Solids During Heating and Codling, by F. C. W. Olsen (In dustrial and Engineering Chemistry, Vol. 34, 1942, pp. 874-877). 14 Applied Mathematics in Chemical Engineering, by T. K. Sherwood and Charles E. Reea (McGraw-Hill Book Co., Inc., 1939). 17 Introduction to the Mathematical Theory of the Condition of Heat in Solids, by H. S. Carslaw (Dover, 1945). 14 Heat Conduction, by L. R. Ingersoll, A. C. Ingersoll and 0. J. Zobel (McGrawHill Book Co., Inc.,1948, p. 209). 14 Applied Mathematics in Chemical Engineering, by T. K. Sherwood (McGraw-Hill Book Co., Inc., 1949, p. 241). , . ., Methods graphiques pour l'etude des installations de Chauffage et de refrigera tion en regime discontinu, by A. Nessi and L. Nissolle (Dunod, Paris, 1949). 41 Method for Determining Unsteady-State Heat Transfer by Means of Electrical Analogy, by V. Paschkis (A.S.M.E. Transactions, Vol. 64, 1942, pp. 105-i0). 77 Heat Insulation in Air Conditioning, by R. H. Heilman (Industrial and Engineer ing Chemistry, Vol. 28, July 1936, p. 782). 77 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). 74 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, pp. 1170-1172). 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 dir 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 ari 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 aiid' 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 33. . 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 111 112 CHAPTER 6 1952 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 Health' (Table 1) and the A.S.H.V.E. Research Laboratory.' 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. , 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 1J air changes per hour are necessary to provide a ventilation rate of 10 cfm per person. Therefore, in the ordinary dwelling with adequate cubic space allot ment, no special provision for controlling chemical purity of the air is necessary (aside from removal of fumes from heating appliances). For such conditions, the control of air temperature is the major consid eration. In more crowded rooms (large offices, large workrooms, auditoriums), where the cubic space per person is less and it is usually impossible to admit untempered outside air without creating drafts, mechanical ventila tion is essential. 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. Notwithstanding the rapid advance made in air conditioning, some per sons still believe there is a stimulating quality in outdoor air (particularly country, mountain and seashore air) under ideal weather conditions, which is lacking in artificially conditioned air. It is apparent, however, that modem air conditioning insures control of the phenomena of nature for the service and comfort of man independently of weather conditions. Freedom of movement, action and thought, together with the variability of stimuli experienced by persons under ideal conditions in the country, mountains or seashore, undoubtedly has some stimulating effect. Various experimenters have attempted to duplicate the invigorating qualities of . Physiological Principles 113 "Table T. Minimum Outdoor Air Requirements to Remove Objectionable Body Odors Under Laboratory Conditions1 . ' . Type of Occupants . Ara Space per Person Cu Ft Outdoor Am Supply CFM per Person..' . Heating season with or without recirculation.. Air not conditioned. . '' ' f Sedentary adults of average socio-economic status....* 'l Laborers................................................ ;.............................. .[ Grade school children ofaverage socio-economic status* .1 Grade school children of lower socio-economic status.... Children attending private grade schools_____________ 100 200 300 500 200 100 200 300 500 200' 100 25 16 12 7, 23 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 30 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 SO 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.5. 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.5 . 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 well. 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 pf physical impurities by air cleanuig methods. (See Chapter 33.) THERMAL INTERCHANGES WITH ENVIRONMENT Body temperature depends upon the balance between heat production uud heat loss. Heat resulting from oxidation in the body (metabolism) 114 CHAPTER 6 1952 Guide 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: M = dz S -J- E R C ' ' (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 lie at a lower level. At this point, which may be termed the neutral point for that individual, conditions, are neither too hot nor too cold. If, through a fall in air temperature, or a rise in air movement, the rate of heat loss from the skin to the environment is increased, 'then the body must do 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 lie 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 fallin 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 vasomotor 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.9 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 * Normal control, naked, in calorimeter at temperatures from 72.8 to 04.1 F. First column in each experi ment represents heat production as determined by indirect calorimetry, the second column, hea t eliminatinti The portion marked with vertical lines represents vaporisation; the dotted area, convection; the unmarked Area, radiation. The skin temperature represents the average reading of 18 spots on the surface. unable to balance the restriction in heat loss, the body has entered the next zone. Once again, the normal body takes steps to prevent a change in its deep temperature; but they are not the counterpart of the steps taken under similar circumstances on the cold side. There is, in fact, very little change in heat production, beyond that resulting from a disinclination for exertion. The second line of defense, on the hot 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 |u the zone of inevitable body healing. The body enjoys a little more latitude m 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 1952 Guide arid air motion are most important. With dry-bulb temperature above body temperature, air motion facilitates evaporative heat loss by removing hpt 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 riormal 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 tjhe 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 DRY'BUIB TEMPIRATURL DEG FAHR (AT 45 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 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 cfressed in customary winter indoor clothing. The Pierce Laboratory data for the semi-reclining subjects also include the rate of heat storage (either positive or negative) due to a rise or fall in body temperature. For the normally clothed subjects, a curve gives the total heat loss (that is, the sum of the radiation, convection and evaporative losses). Here, 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 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 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.12 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. - -t - Table 2. Physiological Responses to Heat op Men at Rest and at Work* Effective Actual Cheek Temp . (Fahb . Deo) Men at Rest Rise in Rectal Temp (Fair Deg per Hr) Increase Approximate in Pulse'' LoesinBody Rate . Weight by (Beats per Perspiration Min per' (Lb per Hr) Hr) Men at Work i. 90,000 tt-lb of Work per Hour Total Work Accomplished (Ft-Lb) Rise in Body Temp (Fahr Deg per Hr) . Increase in Pulse Rate (Beats per Min per Hr) Approximate LonIn Body Wt by Per spiration (Lb per Hr) 60 70 80 85 90 95 100 105 110 96.1 96.6 97.0 97.6 99.6 104.7 -- 0.0 0.0 0.1 0.3 0.9 2.2 4.0 5.9b 0 0 i 4 15 40 83 137,b 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 0.5 0.6 0.8 1.1 1.5 2.0 2.7b 3.5b 4.4b f Data by A.S.H.VJ3. Research Laboratory. Computed value from exposures lasting law? than one hour. HIGH TEMPERATURE HAZARDS .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, flushlng of face and neck, pulse rate above 150, glazed eyes, and mental dis- 118 CHAPTER 6 1952 Guide Table 3. Uppeb Limits op Environmental Conditions fob Acclimatized, Healthy, Young Men in Military Service Environment orReactions at the end 4 hb Rectal Temp F Pulse rate 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.16 . 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 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 period each day. It was found that the ability of a new subject to endure these conditions showed daily improvement for a period of at least 2 weeks. However, after acclimatization was completed, a recess of several days had no effect on the endurance of the subject. Individuals differ widely in their capacity to acclimatize. Acclimatized men lose most of these improvements in a few weeks of temperate climate, even though they are vigorously active. In the course of acclimatization, the sweat glands come 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 op Acclimatized Subjects Working at a Specific Rate10 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 m 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 Laboratory10 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 CHAPTER 6 1952 Guide 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 E!T; 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 os compared with unit rise in ET, as'conditions get hotter. This may be due more to a growing importance of unit rise in ET than to a 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. Fig. 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---Persons 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. All curves:are averages of lvalues for high and low; relative humidities; variation due to humidity is small. | i *j ' 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 Eig. 6. Relation Between Radiation and Convection Loss from the Human Body and Dry-Bulb Temperature for Still Air* 14 a Loc. Cit. See footnote a, Fig. 5. APPLICATION OF PHYSIOLOGIC PRINCIPLES TO AIR . CONDITIONING PROBLEMS In order to estimate cooling loads in occupied spaces it is necessary to know the metabolic rate (heat production) of man. This has been studied extensively, and found to remain relatively constant per unit of body surfece area in a subject fasting and resting quietly after a good night's sleep. Ihe rate is high in children, and diminishes gradually with age; it increases 111 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 vanes widely in different persons doing the same work. Figs. 5, 6, and 7 and Table 28 of Chapter 12 give sufficient basic data for estimating heat pro duction and heat loss under various conditions. 122 CHAPTER 6 . 1952 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 faictors 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. Fig. 7. Evaporative Heat and Moistube Loss fbom the Human Bodt in Rela tion to Dby-Bulb Tempebatube fob Still Aib Conditions* 14 * Loo. Cit. 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 studies22 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 also to a, considerable degree determines the physiological effects on the body induced by heat or cold. For this reason, it is called the effective temperature scale or index, and it denotes sensory heat level. . Effective temperature is an empirically determined index of the degree of warmth perceived on exposure to different combinations of temperature, humidity, and air movement. It was determined by trained subjects who compared the relative warmth of various air conditions in two adjoining conditioned rooms by passing back and forth from one room to the other. The numerical value of the index for any given air conditions is fixed by the temperature of slowly moving (15 to 25 fpm air movement) saturated ' Physiological Principles . T23 .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 measureddirectly, 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 3b0 and 500 fpm have been presented in some of the earlier editions, of the Guide. 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 of Comfobt Ranges With Zone of Thebmat. Neutrality Investigators Effective Temperature Operative Temp Optimum Line Range Range Remarks Comfort Zone Houghten and Yaglou. 66 63-71 Yaglou and Drinker... 71 Yaglou.......................... 72.5 Keeton et al................. 75 66-75 66-82 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 DuBois and Hardy___ Winslow, Herrington and Gagge............ 75 73.2-76.9 71.8 64.8-76.0 Basal; nude; men. . Basal; clothed; mien. . ' 84.0-87.8 Non-basal; at rest; nude: men.' 74 -84 Non-basal ;at rest ;clothed;men. - As stated previously, effective temperature is an index of the degree of warmth experienced by the body. An effective temperature line is, there fore, a fine 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 conditions, with subjects doing light work, were in very close agreement with the effective temperature chart. Other work20 under similar environmental conditions, but with subjects walking 3 mph and carrying 20 lb packs, indicated that the effective temperature lines should be more 124 CHAPTER 6 1952 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 winter 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 The distribution curve, showing the percent of people feeling comfortable 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 percent of people feeling comfortable at various effective temperatures in the winter, was based on research prior to 1932. This curve indicated that at 66 ET a maximum number of people were comfortable. Later studies22 by the A.S.H.V.E. Research Laboratory indicated that a maxi mum of 97.7 percent of the people were comfortable at 68 ET, and this finding has been confirmed by current practice.21 However, adequate data from the later studies were available only for the ET range of 65 to 69, Pro. 9. Effective Temperature Chart Showing Normal Scale of Effective Temperature, Applicable to Inhabitants of the United States Under Following Conditions: :' ,,* Clothing: Customary indoor clothinp. B. Activity: Sedentary or light muscular work. C. Heating Convection type, warm air, direct steam or hot water radiatora, plenum systems. as presented in Fig. 10. The studies should be extended to cover a wider ^ge. 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 1952 Guide measurable degree the optimum conditions for comfort previously in dicated. 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 Physiological Principles 127 Many field studies** 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. .' * ATote--Both summer and winter comfort lines apply to inhabitants of the United States only. Applica tion of winter oomfort 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 lina is liirnitad 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 fine 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, theaters and auditoriums, temperatures somewhat lower than those indicated by the comfort line may be desirable because of counter radiation between' the bodies of occupants in close proximity to each other. Such radiation will also elevate the mean radiant temperature of the room. Fig. 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 studies*5 have shown that for healthy individuals this shock is not harmful, under some conditions it may be unpleasant or >128 CHAPTER 6 1952 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 Laboratory* 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 Illinois17 in cooperation with the A.S.H.V.E. Committee on Research indicate 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 work1* 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 do which equals 0.116 C deg per (kilogram calorie) (square meter) (hour).19 Yaglou* criticizes the concept of overall insulation, and points out that different parts of the body require different amounts of insulation. The literature on effects of clothing is difficult to coordinate at the present time, as much of it is still in military service. reports which are yet to be published and amplified. For prematurely bom infants, the optimum temperature varies from 100 to 75 F, depending upon the stage of development. The optimum relative humidity for these infants is placed at 65 percent.11 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 * 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). ; .. * 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). 4 Tobacco Smoke Control--A Preliminary Study, by Charles S. Leopold (A.S.H.V.E. Transactions, Vol. 51, 1945, p. 255). ' 6 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 Ejmosure 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 Earl 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). . 4 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, Medictu Science, Vol. 3, 1937, No. 4, p. 348; also Transactions of the Association of American Physicians Vol. 51, 1936, p. 252). 4 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). 10 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 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). - 11 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- Teague, W. E. Miller and W. P. Yant (A.S.H.V.E. Transactions, Vol. 35, 1929, p. 245). of Insensible Perspiration (Diffusion of Water) Locally Through Living Through Dead Human Skin, by G. E. Burch and T. Winsor (Archives of Internal Medicine, Vol. 74, 1944, p. 437). 11 The Influence of Clothing, Work and Air Movement on the Thermal Exchanges of Acclimatized Men in yarious Hot Environments, by N. A. Nelson, W. B. Shelly, , Horvath, L. W. Eichna, and F. F. Hatch (Joumal of Clinical Investigations, Vol. 27, 1948, p. 209). .' 14 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-- Turthopgtody 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- 0U (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 ;.aiHumidities in Still and Moving Air, by W. J. McConnell and C. P. Yaglou Transactions, Vol. 31, 1925, p. 101). A.S.H.V.E. Research Report wo. 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-- aeat and Moisture Losses from Men at Work and Application to Air Conditioning by F- c- Houghten, W. W. Teague, W. E. Miller and W. P. Yant .Transactions, Vol. 37, 1931, p. 541). A.S.H.V.E. Research Report pio. no6--Air Conditioning in Industry--Physiological Reactions of Individual Workers to High Effective Temperatures, by W. L. Fleisher, A. E. Stacey, Jr., F. C. a m- B. Ferderber (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 59). -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). r, -f A.S.H.V.E. Research Report No. 1151--The Peripheral Type of Circulatory railure in Experimental Heat Exhaustion, by R. W. Keeton, F. K. Hick, Nathaniel vuickman and M. M. Montgomery (A.S.H.'V.E. Transactions, Vol. 46,1940, p. 157). 14 Heat Disease: Clinical and Laboratory Studies, by M. W. Heilman and E. S. Montgomery (Journal of Industrial Disease and Toxicology, 18:651, 1936). -rp LPerformance in Relation to Environmental Temperature, by L. W. Eichna, 1945 VTFan<f N. Nelson (Bulletin of Johns Hopkins Hospital, Vol. 76, P- 25-58). 130 , CHAPTER 6 1952 Guide u 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). ** Life, Heat and Altitude, by David B. Dill (Harvard University Press, Cam bridge, 1938). . ' ,0 The Upper Limits of Environmental Heat and Humidity Tolerated by Accli matized 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 cology, Vol. 27, March, 1945, p. 59). 11 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). !! 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. Reseahch 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. 32,1926, p. 315). How to Use the Effective Temperature Index and Comfort Charts, by C. P. Yaglou, W. H. Carrier, Dr. E. V. Hill, F. C. Houghten and J. H. Walker (A.S.H.V.E. Trans actions, Vol. 38, 1932, p. 410). !S 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). 14 Conditions for Comfort, by C. S. Leopold (A.S.H.V.E. Transactions, Vol. 53, 1947, p. 295). ,s 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. Keeton, F. K. Hick and M. K. Fahnestock (A.S.H.V.E. Transactions, Vol. 53, 1947, p. 327). ' 14 A.S.H.V.E. Research Report No. 1055--Cooling Requirements for Summer Comfort Air Conditioning, by F. C. Houghten, F. E. Giesecke, C. Tasker and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 43, 1937, p.` 145). 17 A.S.H.V.E. Research Report No. 1012--Study of Summer Cooling in the Re 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). * 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). ,s 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, Vol. 94, 1941, p. 428). . Thermal Insulation of Clothing, by C. P: Yaglou (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, Sept. 1948, p. 107). ,l Application of Air Conditioning to Premature Nurseries in Hospitals, by C. P. Yaglou, Philip Drinker and K. D. Blackfan (A.S.H.V.E. Transactions, Vol. 36, 1930, p. 383). . CHAPTER 7 AIR CONDITIONING IN THE PREVENTION AND TREATMENT OF DISEASE Sanitary Ventilation, Control of Airborne Infection, Value of Air Cooling Under "Tropical Conditions, Treatment of Disease, Operating Rooms, Nurseries for Premature Infants, Fever Therapy, Cold Therapy, Allergic Disorders, Oxygen Therapy, General Hospital Air Conditioning THE late 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, or any buildings, following an atomic explosion has the attention of engi 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 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 number of people using the shelter, are factors in determining the neces sity for using outside air. Such a shelter should be closed to outside air during the period immediately following a blast. `. A surface or subsurface atomic burst would result in wide dispersion of radio-active particles in high concentrations.1 There is relatively little 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. The recent 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.* 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 o? containments, 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 situation at Donora. The U. 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. This 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 1952 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.* 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. Three important documents have appeared in English, Swedish and French literature recently.4' *6 ; In this country, where the study initiated, the Council of Physical Medicine of the American Medical Association approved the radiant dis infection 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 ASHVE has from time to time reported progress in the Journal since 1944, and has approved a set of definitions, formulations and factors which is now being reviewed by the Committee of Research and Standards of the A.P.H.A. with the purpose of joint adoption by the Association and the Society. Since this important new field of sanitary ventilation is yet in its infancy, just emerging from the research and development stage, it has not been possible to prepare a comprehensive treatment in The Guide. Those pro fessionally interested must still refer to the official publications of the or ganizations listed, and the enormous technical literature on the subject which they review. The following section on Control of Airborne Infec tion 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 to the outside air to conserve warmth, as well as the crowding of persons indoors, provides conditions conducive to a high incidence of contagion. 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 tion) is a major intrinsic factor. Apart from the seasonal picture of air borne contagion, are such extrinsic factors as rate of turnover of personnel, and the marked susceptibility of the recruit in comparison with permanent personnel11 as shown in Fig. 2 by studies of military personnel housed in barracks. These extraneous variables and the factor of contact infection (direct spray) tend to complicate any evaluation of the effectiveness of air sanitation for elimination of micro-organisms in droplet-nuclei and drop let-dust. Thus, control measures may eliminate consistently 90 percent of airborne organisms in laboratory tests, but cannot effect a decrease in actual incidence of infection exceeding 30 percent. Thirty percent may Air Conditioning in Prevention and Treatment of Disease 133 be the maximal reduction in infection possible by air treatment methods. . 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.11 .. The following sequence of events has been postulated as occurring' in a large proportion of intra-ward infections: (o) 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- Fig. 1. Study ofAverage Monthly Frequency (1921-1926 inclusive) of Speci fied 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: (o) suppression of dust and lint, and (b) disinfection of dropletnuclei. A third measure, control of relative humidity is important. It aas been shown that the viability of certain organisms sprayed into the atmosphere from a liquid suspension is dependent on relative humidity, fhe mortality rate of the organisms is very high at a relative humidity of 50 percent,14 and decreases at humidities above and below this figure. It 134 CHAPTER 7 1952 Guide 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 barracks18,17 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 bacteriologic 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. Fig. 2. Monthly Incidence of Acute Respiratory Illness Among Naval Re . cruits and Ship's Company (Permanent Personnel)1 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, " 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 Air Conditioning in Prevention and Treatment of Disease 135 the number of air changes per hour, is important and that continuous va porization is needed to maintain effective concentrations of glycol vapor.21 \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 Uquid 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 4000 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.27 Under practical conditions, particularly in the presence of dust in the air, glycol effectiveness is much reduced. The use of other chemical aero sols 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 about five times that recommended commercially. No significant effect in the incidence of disease could be detected in about 400 inmates during the six-year period. The data imply that air layers were not sufficiently mixed. However, more efficient mixing would have been obtained at the expense of increased 136 CHAPTER 7 1952 Guide circulation of dust and lint. Sources of ultraviolet radiation should be so situated as to protect the eyes of the occupants of the room from direct or reflected rays. A combination of ultraviolet radiation and dust 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. "i:; 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.9 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 bums, 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 bum 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. 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 ronment. The gradient between the body surface temperature and the environmental temperature is such that loss by radiation is slight. The heat loss by evaporation in a warm, humid environment is low whether the patient does or does not perspire. 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 anoter influ 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 tem perature height of patients with various acute febrile diseases.30 Air Conditioning in Prevention andTreatment of Disease .137 ^Frequently from ;50..%iSj75cpfcEcefit;:of -perSoBnel.Abq^clijQavat vessels operating Sst tropicaL-waters ate afflicted with heat rash\tp a.vdegree that mterfereSi.)sdth rest and? sleep. In carefully, controlled experiments29 it was posable-to produce a fulminating type oJ,rash in all.men living conT tinuoii^ly at an effective,temperature :of. $5 (j^F dry-bulb tmd 83 F wet- bulb)K. In the control group, 12 oujiibf 24,lir were spent in a relatively cool atmosphere of 75. ET (80 F dry-bulb, and 70;F wet-bulb). - These men either remained free |rom,heat rash, or ocfiasjo^fly developed a mild form'. Thus, .ihtermittent'qoolihg to a degree; whicnprevented sweating in men at test 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 deep without excessive-sweating. Berthing spaces tended to have ex tremely low odor levels; Rfotivation, initiative and alertness, in contrast to the usual irritability and lack of incentive incident to residence in tropical climate, were maintained.81. . . .. 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 infants, 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 theymay 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 heat regulatory center of the brain. Obviously, one: of the most important 138 CHAPTER 7 1952 Guide factors ini recoveiy 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 burns 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, diy 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 be cause winter humidification helps reduce the danger of anesthetic gases; summer cooling with some dehuinidification 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. Reducing Explosion Hazard Explosion hazards in operating rooms began with the introduction of modern 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 oxygen, 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 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 into the air may accumulate to any lower concentration, and thus introduce a serious hazard. The.most dangerous period is at the end of the operation when the patient's lungs and the anesthesia apparatus are customarily washed out with- oxygen with or without the addition of carbon dioxide: Even when this procedure is omitted, it is difficult in practice to avoid dilution of the anesthetic gas with air during the normal course of breathing following the administration. In. either case the mixture would pass through the explosion range and extraordinary precaution is necessary for the safety of the patient and operating personnel . ... In a study34 of 230 anesthetic explosions and fires, 70 percent of the ex 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. In 1941 the National Fire Protection Association35 made certain recommendations for safe practice based on available infor mation. Some of these recommendations are: Windows should be kept closed so that the air conditioning system can prevent pooling of explosive anesthetic gases. Twelve air changes per hour and a humidity of 55 percent are advised. If a higher humidity were compatible with the well being of the patient and personnel, it should be maintained. All electrical installations should comply with the standards set by the National Electrical Code for use in ex plosive situations. Cautery equipment should not be used in hazardous locations. To prevent static sparks, ml bodies in an operating room should be conductive or coupled. It is essential that adequate grounding be provided for the floor and every object in the operating room. Conductive rubber should be used on shoes, leg tips, operating table coverings and all rubber parts of the anesthesia equipment. All furniture in contact with the floor should be metal. In the absence of complete grounding facilities, the simple method of intercoupling patient, operating table, anesthetist and gas machine at ground potential maybe used. 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- It should be realized that when a room and the occupants have been com- pletely grounded, there is always the possibility that'the patient or the operator might receive a dangerous shock if a short circuit developed in any of the electrical equipment. ' 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, arid 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 httle more than 0.8 F variation in the rectal temperature during the course of the operation.36 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 cooi ng- 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 140 CHAPTER 7 1952 Guide . 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 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 cases. . ' ' " In the control of airborne infection in the operating room, the prevention of dispersal of infectious materials into the air, control of dust, and proper ventilation supersede 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-hours*7 without replenishment. The removal of bacteria by the process of air cooling and condensation of mois ture out of air, merits further study.*8 : 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 whieh protect the patient against infection from attendants, and from bacteria-containing air in the corridor or ward.83 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 prove satisfactory in operating rooms when producing between 8 and 12 air changes per hour, of filtered and properly conditioned air, without recircu lation, during the course of anesthesia. A separate exhaust fan system, is usually necessary to confine and remove the gases and odors. Double windows are desirable and often necessary to prevent condensation and frosting on the glass in cold weather, and to minimize draffs. The air flow of 8 to 12 air changes in operating rooms should: (1) reduce the concen tration 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 pre paring the room for emergency operations. Much can be gained by ther mal insulation of sterilizing equipment, and by thorough exhaust ventila tion 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. 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 Air Conditioning in Prevention and Treatment of Disease 141 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 research40 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 nursery 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. . Importance of Humidity: Although external heat 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-ihtestinal 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 life) was found to vary inversely, with.the humidity. In the old nurseries with.natural humidfly 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 tp 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 the installation 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 1952 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. Air Conditioning Equipment Many of the installations now in use are of the central system type pro jecting for filtration, for humidification and heating in cold weather, and for cooling and dehumidification in hot weather. A ventilation* rate be tween 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. 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 Bacterkd 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 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 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 blisters and mild dehydration. The limits of induced systemic fever are usually between 104 and 107 F (rectal), and the: duration from 3 to 8 hours at a time. The total period of fever 'treatment varies with the type of the organism involved. The diseases which respond favorably to artificial fever therapy are gonorrhea and its complications (which include arthritis, pelvic infections in women, and involvement of the eye), syphilis and chorea. The most striking results are seen in' gonorrhea and syphilis, since the causative organisms can be destroyed at temperatures compatible with human life. However, the use of fever therapy has decreased since peni cillin has been found so effective in the treatment of gonorrhea and syphilis. Mild fever, up to 101F for one hour, has recently been used in the treatment of rheumatoid arthritis. This degree of fever is not bactericidal, but is believed to stimulate the body defense mechanism. Air Conditioning in Prevention and Treatment of Disease 143 Equipment for Production of Fever . . . Artificial fever can be induced by injections df 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.42 Among the devices for the production of fever by physical means, the one most widely used is the hot humid air or air conditioned, cabinet.: This apparatus was developed at the Kettering Institute for. Medical Re search at Miami Valley Hospital in Dayton, Ohio. ., In the earlier studies of the Society, temperatures were elevated more easily using saturated atmospheres. A fever, therapy apparatus43 using these same principles has proved efficient as a means of inducing and main-, taining fever in a body, with small likelihood of bums 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 bums 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 of an extremity is not indicated, the application of a tourniquet and pack- 144 CHAPTER 7 1952 Guide mg 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 wth 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. cancerdjgs not proven successful. . The methods used for refrigeration, depending upon available facilities, are as follows:44 "" ' (1) Cracked or shaved ice which is simple and has the advantage of not freezingtissues. However, it is cumbersome and sloppy to handle and is unsuited to pro longed treatments. (2) rise 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 add" 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 in the form of blankets containing rubber tubes suitable for covering the entire body, or'all or part of a limb. Special applicators are available for insertion into various body cavities, and for 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 bronchial1 asthma. . It is commonly known that non-specific environmental factors such as dust; irritating gases, change of temperature and humidity may precipitate asthmatic attacks in allergic subjects, even in the absence of exposure to specific allergens. It is assumed that the presence-of frequent allergic bronchial constriction renders the smooth muscles of the bronchi so sensi1 tive to various 'non-specific stimuli that the threshold of their response to such irritation inconsiderably 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.46 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 air. A pollen-free atmosphere is especially valuable when desensitization has given little or no relief, and when desensitization is not advisable owing to intercurrent illness. OXYGEN THERAPY Oxygen therapy is used to prevent or relieve anoxia. Some of the more important clinical conditions in which oxygen treatment is beneficial in clude pneumonia, severe anemia, cardiac decompensation, pulmonary ate- 146 , CHAPTER 7 1952 Guide lectasis, 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.17 The necessity of air conditioning in oxygen therapy arises .from the fact that oxygen is too expensive a gas to waste in the ventilation of oxygen "tents and oxygen chambers. Air conditioning is applied to the oxygen tent or chamber through reconditioning of the atmosphere in a closed circuit. Excessive heat, moisture and carbon dioxide are removed. Oxygen Tents ' : In oxygen tents, the air enriched with oxygen is usually circulated by means of a small motor blower which sends the air over soda lime to remove carbon dioxide, and then over ice to remove excess heat and moisture. The concentration of oxygen in the tent is regulated by means of a pressure reducing valve and flow meter. In an inadequately cooled tent, high 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, 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, to avoid loss of oxygen. Glass windows in the ceiling and walls admit light from outside the chamber. The air conditioning system may be of the gravity type, or of the fan type using mechanical refrigeration or air drying agents.. .. The temperature and humidity requirement in oxygen therapy depends primarily upon, the physical condition of the patient, and secondarily upon the type of disease. In pneumonias48 prescribed conditions should be a temperature of 60 to 75 F, humidity 20-50 percent, moderate air move ment, oxygen concentration of 50 percent, and carbon dioxide of less than one percent. . Oxygen in Aviation . An important application of the principle of oxygen therapy is in aviation. At the present time all high altitude military airplanes in this country areprovided with gaseous oxygen equipment, and military personnel are re quired to utilize oxygen at all times while in flight above 15,000 ft, or be 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 during the cool season of the year can be satisfactorily fulfilled by the use of con ventional heating equipment, in conjunction with window air supply and gravity or mechanical exhaust. Insulation against heat and sound is much more important than 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 Put 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 AngloTlranian 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 ET) 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 re sults.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 and vapors, perfumes, oxidizing gases and simple exhaust methods are unsatisfactory. An ideal deodorant would purify the air by means of odor adsorption so that subsequently the air can be recirculated.  i 148 CHAPTER 7 - 1952 Guide Air Conditioning in Prevention and Treatment of Disease 149 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 81 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). methods for elimination of odors over other methods remains to be an swered. The present status of the problem is that the commercial aspect ` 88 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). r is highly controversial.60 88 Glycol Vapors for Disinfecting Purposes, Editorial (Journal of the American Medical Association, 133:696, March 8, 1947). . '' ' REFERENCES - 84 An Experiment with Triethylene Glycol Vapor for the Control'of Colds Among Office Employees, by W-J-McConnell (IndustrialMedicine, 18:5,192-196, May,1949). I The'Effects of Atomic Weapons, Revised September, 1950.. (For sale by the 88 Ultra-Violet Light Control of Air-Borne Infections in a Naval Training Center, :{ Supt. of Documents, U. S. Government Printing Office, Washington 25, D, C.).. . . by S. M. Wheeler, H. S. Ingraham, A. Hollaender, N. D..Lill, J. Gershon-Cohen, ` Investigation of the Smog Incident in Donora, Pa., and Vicinity, by James G. and E. W. Brown (American Joumat of Public Health, Vol. 35, p. 457,1945). i 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., 88 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, Industrial Medicine and Surgery, 19:97-101, March, 1950). W. C. Dreessen, P. A. Nealand, and I. Possner (American Journal of Hygiene, 48: ' 4. Studies in Air Hygiene, by R. B. Bourdillon, O. M. Indwell and J. E. Lovelock 207-226, Sept., 1948). .. . with W. C. Cawston, L. Colebrook, F. P. Ellis, M. Vanden Ende, R. E. Glover, A. 87 Recent Studies on Disinfection of Air in Military Establishments (American M. Macfarlan, A. A. Miles, W.:F. Raymond, E. Schuster and J. C. Thomas (Medical Journal of Public Health, Vol. 37, p. 189, Feb. 1947). i Research Council of Great Britain,1948. Special Report Series No. 262). 88 Commercial Exploitation of Glycol Vaporizers (Editorial in American Journal . * Ultraviolet Irradiation with Artificial Illumination, by.Hans E. Ronge, Uppsala, of Public Health, Vol. 39, No. 2, February 1949, p. 222). Sweden, 1948,191 pages. L'Hygiene du.Batiment per L'Ultra-violet by P. A. Burrucand, Centre Scien 88 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. tific et Technique du Batiment, Paris, 1949. - : -. - Pitts, W. A. White, Jr., W. V. Consolazio, and L. J. Pecora (Research Project X-205, ' ` Acceptance of Ultraviolet Lamps for Disinfecting Purposes,'Council of Physical Therapy (Journal of American MedicalAssociation, 122:503-504,1943). . Report No. 2, Naval Medical Research Institute, Bethesda, Md., May, 1945). 88 Mechanism of Heat Retention, by F. K. Hick and M. M. Montgomery. (Un 8 Evaluation of Methods to Control Airborne Infection, by. J. E. Perkins (Ameri published) . can Journal of Public Health, Z5:SSl-$&7,1045). . The 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). \ 81 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). 10 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.) II Factors in the Control of'the Spread of Acute Respiratory Infections with Ref erence to Streptococcal Illness and Acute Rheumatic Fever, by 8. M. Wheeler and T. D. Jones (American Journal of the Medical Sciences, 209:58, 19-15). . " Dust Control, Report on Suppressive Measures for the Control of Diist, 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). , : . s. u Laboratory and Field Studies of Glycols and Floor-Oiling in the Control of Air Borne Bacteria, by A. P. Krueger, et cd (U. S. Naval Medical Bulletin, 42:1288,1944). ** The- Lethal Effect of Relative Humidity on Air-Borne Bacteria, by Edward W. Dunklin and Theodore T. Puck (Journal of Experimental Medicine; Si :87-101, Feb., 1948). - :' ' ' 16 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. 18 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). : .. 18 Lethal Effects of Triethylene Glycol Vapor on Air-Borne Bacteria and Influ enza Virus, by O. H. Robertson, et al (Science 97:142, 1943). . .' `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, 209:162, 1945). . V; - 88 Summary of a 3-Year Study of the Clinical Applications of the Disinfection of Air by Glycol Vapors, by T. N. Harris and J. Stokes, Jr. (American Journal of the Medical Sciences, 209:152, 1945). .. , ` 88 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). 88 Fundamentals of Anesthesia (American Medical Association Press, Chicago, HI., 2nd Edition, 1944, p. 204). 84 The Hazard of Fire and Explosion in Anesthesia, by B. A. Green (Anesthesioloay, 2:144, 1941). 88 Control of Physical Hazards of Anesthesia, by R. M. Tobell and A. W. Friend (Canadian Medical Association Journal, 46:560, 1942). 88 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. Leigh Cook, Jr. (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 161). 87 Unpublished Naval Studies, by A. R. Behnke and O. Schneider (1940). 88 Disinfection of Air by Air Conditioning Processes, by C. P. Yaglou and Ursula Wilson (American Association for the Advancement of Science, Publication No. 17, d. 129). 88 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). 48 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 Journal 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). ' 48 Physical Medicine, by F. H. Krusen (W. B. Saunders Co., Philadelphia and London, 1941). . . 48 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-- 150 , CHAPTER 7 1952 Guide ' . Eever Therapy Locally Induced by Conditioned Air, by M. B. Ferderber, F. C. Houghten and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 307). Refrigeration for Anesthesia and Therapy, by L. W. Crossman and S. K. Safford (The,Modem Hospital, 64:86, 1945). . ' 7--.. . . - . . <s The Effect of Low Relative Humidity and Constant Temperature on Pollen Asthma, by B. Z. Rappaport, T. Nelson, and W. H. Welker (Journal of Allergy, 6:111, 1935). . . , " Hospital Air Conditioning, by C. P, Yaglou (The Environrnent and Its Effect Upon Man, Harvard School of Public Heallh.p. 244, 1939). . Principles and Practices of Inhalational Therapy, by A. L. Barach (J. B. Iippincott Co., Philadelphia, London, Montreal, 1944). 48 The Management of Pneumonia,- by- j. G. M. Bullowa (Oxford University Press, p. 260, 1937). . . : .* What Are the Right Conditions, for Comfort Cooling, by Cyril Tasker (Heat ing, Piping, and Air Conditioning, Aug., 1948, p. 84). . . . 80 Odors Physiology and Control, by C. P. McCord and Wm. R. Witheridge (Mc Graw-Hill Book Co., 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; Maximum Allowable Concentrations of Industrial -Air ' Contaminants; Flammable Gases and Vapors; Combustible Dusts; Atmospheric Pollen; Airborne Bacteria '. THE normal constituents of the earth's atmosphere are, oxygen, nitro gen, carbon dioxide, water vapor, argon, small or negligible amounts of other inert jgases, hydrogen, variable traces of ozone, and small quanti ties of microscopic and submicroscopic solid matter, sometimes called permanent atmospheric impurities. From the viewpoint of the air condi tioning engineer, all other airborne substances may be termed contaminants. This term is applied preferably, however, to undesirable or chance im purities, 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 sub stances 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, windstorm, sea-spray evaporation, thermal disintegration, earthquake; volcanic eruption, combustion, manufacturing, transportation; agricul ture; and the biochemical or biological processes of life. They are classi fied at various times as organic and inorganic, visible or invisible, micror scopic or macroscopic, 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 Dusts, 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, grinding, 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 dust unless they are smaller than about 100 microns. Dusts may be of .mineral type, such as rock, ore, metal, sand; vegetable, such as grain, flour, wood, cotton, pollen; or animal, such as wool, hair, silk, feathers, leather. Fumes are solid particles commonly formed by the condensation of vapors from normally solid materials such as molten metals.' Metallic fumes generally occur as wie oxides in air because of the highly reactive nature of finely divided matter. Fumes may also be formed by sublimation, distillation, calcination, or chemical reaction, whenever such processes create airborne particles predominately below the 1 micron size. Fumes permitted to age tend to flocculate into clumps or aggregates of larger size, thereby facilitating removal from air. . . Smokes are the extremely small solid particles produced by incomplete combustion 151 152 CHAPTER 8 1952 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 are 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 as 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 cpmmonly 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. -- 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 . 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 liquids arranged according to size on the micron scale. There are 25,400 microns in 1 inch. Particles larger than 10 microns are unlikely to remain suspended in air currents of moderate strength, but settle out by gravity at speeds dependent upon the shape, size and specific gravity of the particle, wind velocity, orientation of the collecting surface, and topography. These larger particles are of major interest to the engineer in the solution of nui sance problems, but it is usually the smaller particles, or those below 10 microns, that remain in the air long enough to be of hygienic as well as economic significance. Industrial dust particles are predominantly of the order of 1 micron in size. Tremendous numbers are also present in the submicroscopic range below 0.5 micron, but those below 0.1 micron are not believed at present Air Contaminants 153 to be of practical importance, possibly due to their 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). .. Compiled by W. Gj Frank and Copyrighted, used by permission. Fig. 1. Sizes and Characteristics of Airborne j?articulate Matter The survey1 of atmospheric pollution in 14,Anaerican cities conducted from 1931 to 1933 indicated the average/si^pf; outdoor dust particles to be 0.5 micron, as collected by the Owens jet dust, counter and measured under the microscope. Inability .of the light field microscope to reveal 154 CHAPTER 8 1952 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 reference 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 correspond ing 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 Tabu: 1. Relation of Scbeen 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 10)0 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 ASTM 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 faU 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 combustion control methods in his local ity, but it does not provide a suitable index of the suspended dust'that air cleaners in a ventilating system are expected to capture.5 * * Gravi metric or weight data of the type given in Table 2 are preferable. In some cases airborne particle counts may be necessary, as for pollen, bac teria, 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, increase 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 13, 14 and 15 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 2-40 4r-400 4000-200,000 * 1 grain per 1000 cu ft = 2.3 milligrams per cubic meter. 1 os per cubic foot =* 1 gram per liter = 1000 grama per cubic meter Milligrams per . Cubic Meter 0.05-0.5 0.1 - 1.0 0.2 - 5.0 0.5 -10 10-1000 10,000-500,000 Many present ordinances limit the number of minutes in any one hour that smoke of a specified density (determined by comparison with a Ringelmann Chart which is described in Chapter 49) 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, accumu lation 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 ^nog (Pennsylvania 1948) are classic examples in the history of gaseous eir pollution. In both instances it is believed that irritant gases, princi- 156 i -CHAPTER 8 1952 Guide 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'Tadiation in Baltimore6 by actinic methods demonstrated that ultraviolet light: intensity in the country was 50 percent greater than in the city. In Newr York City7 a loss as great as 50 percent 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 land 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. * * !0-11 - 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. However, the . engineer will find, at times, that odors originating outside buildings in industrial or business districts may determine the kind and capacity of equipment he must provide for a high quality air supply instal lation. INDUSTRIAL AIR CONTAMINANTS Many industrial processes are sources of contaminants. Their control is an important function of the ventilating or air conditioning engineer, because the atmosphere within buildings is the medium whereby such finely divided matter is dispersed and transported from the source to remote locations where it may cause property damage, nuisance, fire, ex plosion, disease and even death. Tables 3, 4 and 5 give the maximum allowable concentration values for many industrial air contaminants as adopted by the Sectional Committee Z37 on Allowable Concentrations of Toxic Dusts and Gases of the Ameri can Standards Association, and as reviewed annually by the Committee Air Contaminants 157 on Threshold Limits and adopted by. the American Conference of Govern mental Industrial Hygienists at its 1951 meeting. f 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.IJH. values, reliability of the A&4 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 dayB 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 MA.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, wllile 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 MAC. values; Column 2, those of the A.C.G.I.H. Committee on Threshold Limits. Column 3 gives th'e 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 a number of industrial dusts as given were obtained from data of the A.C.G.I.H, Committee on Threshold Limits. i ' 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 budding construction, and installation of automatic alarms. Some 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 1952 Guide ' Table 3. Maximum Allowable Concentration op Gases and Vapors SUBSTANCE ASA STAND- M.A.C. ppm by volume. Threshold Limit Values A.C.GJ.H.* 1951 ppm Gm/cu m or ' Oz/1000 ci Oz/1000 cu ft Acetaldehyde..................... ......:...................... . Acetic acids....................................... .................. Acetic anhydride............................................... -Acetone................................................................. Acrolein.................................'................................ Acrylonitrile........................................................ Ammonia.............................................................. Amyl acetate....................................................... iso-Amyl alcohol............................................... Aniline................................................................... Arsine..................................................................... Benzene (benzol)............................................... Bromine................................................................ 1,3-Butadiene..................................... ............... n-Butanol......................................:.................... 2-Butanone....................................... -............. n-Butyl acetate.................................................. Butyl `'cellosolve"............................................ Carbon dioxide................................................... Carbon disulfide................... `........................... Carbon monoxide............................................. Carbon tetrachloride....................................... "Cellosolve"........................................................ * 'Cellosolve" acetate........................................ Chlorine................................................................ 2-Chlorobutadiene................................................ Chloroform........................................................... 1-Chloro-l-nitropropane................................... Cyclohexane. ..............................................----Cyclohexanol....................................................... Cyclohexanone................................................... Cyclohexene......................................................... Cyclopropane (propene)................................. o-Dichlorobensene............................................ Dichlorodifluoromethane..............'.................. 1.1-Dichloroethane...................... ;*: 1.2-Dichloroethane (ethylene dichlonde) 1.2-Dichloroethylene.......................................... Dichloroethyi ether......................................... Dichloromethane................................................... Dichloromonofluormethane............................ 1.1-Dichloro-l-nitroethane............... 1.2-Dichloropropane (propylene dichlo ride).................................................................... Dichlorotetr&fluoroethane................................ Dimethylaniline................................................ Dimethylsulfate........................................... Dioxane................................................................. Ethyl acetate......................... ............................ Ethyl alcohol...................................................... Ethyl benzene............. ...................................... Ethyl bromide................................................... Ethyl chloride. ... _......................................... Ethylene chlorhydrin................... .................. Ethylene oxide................................................... Ethyl ether............. ............................................ Ethyl formate..................................................... Ethyl silicate....................................................... Formaldehyde.................................................... Gasoline................................................................ Heptane................................................................ Hexane.............................................. '................. Hydrogen chloride............................................ Hydrogen cyanide............................................ Hydrogen fluoride............................................. 100 20 100 10 200 10 5 500 0.5 0.36 0.02554 0.02085 1.2065 0.1145 20 0.04336 100 200 1.064 100 0.36 5 0.019 0.05 35 1 1000 50 0.11393 0.00653 2.210 0.1515 250 200 200 5000 20 . 0.735 0.948 0.966 0.0622 100 50 0.313 200 0.736 100 0.54 1 25 0.0905 100 0.488 20 0.101 400 1.375 100 , 0.409 100 400 400 50 1000 0.401 1.34 0:6875 0.3005 4.94 100 0.405 75 0.3038 200 0.794 15 0.0878 500 1000 10 1.74 4.20 0.0589 75 1000 0.3265 6.98 6 1 100 400 1000 6.02475 0.00515 . 0.36 1.44 1.881 200 200 1000 5 100 0.868 0.892 2.64 0.01645 0.18 400 1.212 100 0.303 100 0.851 5 0.006135 500 2.045 500 2.05 500 1.76 6 0.00746 10 0.01104 3 0.00245 0.43 0:02 0.02 1.21 0.013 0.05 1.16 0.41 0.02 0.12 0.03 3.3 0.18 0.88 1.04 1.02 0.05 0.19 0.76 0.53 0.09 0.31 0.08 1.69 0.42 0.41 1.58 0.91 0.24 3.18 0.33 0.23 0.59 0.08 1.25 2.83 0.4 0.29 4.36 0.02 0.002 0.33 1.52 2.2 0.96 0.59 2.75 0.015 0.09 1.67 0.315 0.87 2.89 2.87 2.54 00..0001-s 0.002 Air Contaminants 159 Table 3. Maximum Allowable Concentration of Gases and Vapors . . (Concluded) :' Substance ASA StandABDS . MAC. ' ppm by volume Thbesbold Limit Values^ : ppm Gm/cu m ' or O1/1000 cu ftb: Oz/1000 cu ft . Mesityl oxide....................................................... Mononitrotoluene......................................................... Nitrogen oxides (other than nitrous ox- 1,1,2,2-Tetrachloroethane............................ . 20 . 200. 100 25 400 200 ? 200 200 0.05 20 25 .200 200 20 100 25 . 25 100 500 100 100 100 100 75 1000 5 , 200 500 1 100 . 25 0.5 100 50 500 1 1000 200 1 0.05 0.5 400 200 500 0.1 500 200 1 10 5 , 100 200 100 100 500 200 0.1208 nU.'jWrafl A OKCJ 0 400 0A465 5.61 0.638 1.945 0.307 _ .. . 0.182 r94 0.704 0.00281 0.834 2.085 2.845 0.85 0.343 0.679 0.752 0.0219 0.536 0.556 1.28 0.868 ' n nmo * ` 0 111 ' n*ni Oil 2.44 .0.48 ' 0.25 0.49 . 0.71 2.6 0.006 0.004 0.275 . .. 0.003 . 4.5 0.82 0.0018 0.885 2.75 . U.IHU 0.02 0.405 0.83 0vA.C.G.I.H. = American Conference of Governmental Industrial Hygienists. Liquid ounces .(at 20 C) of chemical in 1000 cu ft. * 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 to limit the concentration to J or J of the lower explosive limit, and this fact should be given full weight in determin- mg the capacity and design of ventilating equipment. Rarely should 160 . CHAPTER 8 1952 Guide 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 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 point is a convenient method of expressing this property in terms of the temperature scale. It may be defined as the temperature to which a com 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. Table 4. Limits fob Toxic Dusts, Fumes and Mists Substance A.S.A. Standabds, M.A.C. mg/cu m Threshold Limit Values, A.C.QJ.H. 1051 mg/cu m Antimony..... Arsenic.............. . Barium............... Cadmium......... Chlorodipbenyl Chromio arid & chromates (As CrOi......................................... Cyanide as CN............ :....................................................................... Dinitrotoluene................ ..................1.................................................. Fluorides........................................................... ...................................... Iron Oxide fume. Magnetiiiim oxide fume..................... Manganese.................................. -.......... Mercury................................................... Pentachloroanphthalene................... Pentachlorophenol............................... Phosphorus (yellow)....................... Phosphorus pentachloride............... Phosphorus pentasulfide................... Selenium compounds as selenium. Sulfurio acid........................................... Tellurium................................................ Tetnd....................................... ^.............. Trichloronaphthalene......................... Trinitrotoluene... Zinc oxide fumes 0.1 (W) 0.1 , 0.15 0 0.1 u.o 0.1 1. 0.1 5 1.5 2.5 15 0.15 15 6 0.1 0.5 0.5 01 .1 01 .1 0.1 1.5 5 1.5 15 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 pr vapors must be applied with caution; the reader is referred to other publi; cations for this information.11 18 . ' Design of equipment for the control of combustible anesthetics is out lined in Chapter 7. Construction of equipment for handling air contain ing flammable substances, or, operating in atmospheres so contaminated, is discussed in Chapter 45. : . 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 f= 10,000 Air Contaminants 161 ppm (parts of contaminant per million parts of air, by volume, or in other words, cubic feet.of .contaminant per.million pubic 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 from 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. Table 5. Limits fob Minebal Dusts : Substance . Threshold Limit Values A.C.QJ.H. 1951 mppcf^ ; v ,, . * mppcf--million particles per cubio foot of air, standard light field count. 50 50 50 . .1; * 2o " - 50 ' 5 20 50 50 ! ' * ' 20 20 50 , Thus the air conditioning engineer is involved for two reasons: (1) 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 opera tion. (See Chapter 45). 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 in1' the air; moisture content and composition of the air; size and temperature of the ignition source; and degree of dispersion of the dust cloud. Investigations on the explosibility of dusts require determina tion of the maximum pressure developed during explosion of a known air concentration, as well as determination of the rate of pressure rise. In 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 162 CHAPTER 8 1952 Guide , Table 6. Approximate Limits of Flammability of Single Gases and Vapors. In Air at Ordinary Temperatures and Pressures* , Gas oh Vapor Lower Limit..; Percent by ' Volume ' --.-Upper Limit , . Closed Cuph .Percent BT . Flash Point _ .Volume ,. Fahrenheit. Acetyldehyde.......... ............................. Acetone. ...........................................- Acetylene.................... f-. - -v-............ Allyl alcohol............................................ Ammonia................................................. ' ' 4.0 5 2.5 - .. 2.5 . . `2.5 ! 15:5 57 12.8 ...80 . . 26.6 -17 0 70 Amyl alcohol......................................... Amyl chloride....................................... Amylene............................. ..........-- Benzene (benzol) --' - - Benzyl chloride :--'`1.2 * 1.6 . 1.6 . 1.3 ; : 1.1 . \ .* 7.7 6.8 100 12 . 140 Butane .......... Butyl acetate.. Butyl alcohol.............. ......................... Butylene ................................................. Carbon disulfide ..:.................... '1.8 1.4 1.7 2.0 1.2. " - 8.4 ' ' - 15.0 .V 9.7 .. . .50 . 84 ; -22 . Carbon monoxide .>............................. Crotonaldehyde.................................... Cyclohexane.......................................... Cyclopropane................................. Decane......... ................................------- 12.5 2.1 - 1.3 2.4. 0.67 . * 74.2 15.5 .. 8.4 10.5 2.6 , 55 1 il5 Dichloroethylene (1,2)................... Diethyl selenide. ............................... Dioxane......... ....................................... Ethane ................................................. Ether (diethyl) . ................................ 9.7 12.8 2.5 2.0 22.2 3.1 12.5 1.8 36.5 57 54 -49 Ethyl acetate....................................... Ethyl alcohol....................................... Ethyl bromide. ....................'............. Ethyl cellosolve.................................. Ethyl chloride..................................... 2.2 11.5 ' 28 ' 3.3 19.0 ' ' 54 6.7 2.6 11.3 15.7 - io4 4.0 14.8 , "58 ' Ethylene............. ................................. Ethylene dichloride........................... Ethyl formate..................................... Ethyl nitrite......................................... Ethylene oxide.................................... 2.7 28.6 6.2 15.9 56 2.7 16.5 -4 3.0 50 -31 - 3.0 80 Furfural (125 C)................................. Gasoline (variable) ................ Heptane................................................. Hexane................................................... Hydrogen cyanide............................. 2.1 1.4-1.5 1.0 1.2 5.6 7.4-7.6 6.0 6.9 40.0 140 -50 25 -15 Hydrogen.............. ............................... Hydrogen sulfide ............... ......... Illuminating gas .(coal gas)............ Isobutyl alcohol........... . Isopentane...... ................ Isopropyl acetate'............................. . Isopropyl alcohol. ............................. Methane.......................;................_ - Methyl acetate. ................... ; Methyl alcohol................................... . 4.0 -' ' 74.2 4.3 . i ; 5.3 . . 45.5 33.0 - '1.7 1-3 :,n -- 00 1.8 '- .. 2.0 : 5.0 . 3.1 - 6.7 15.0 , -15.5 36.5 . ` .: 82 43. 63 . i4 52 Methyl bromide........................... ............ .............. _ . Methyl butyl ketone........:............................ - Methyl.chloride.................................... .. ... Methyl cyclohexane......................1............... : ' Methyl ethyl ether.........................................."' ` . 13.5 1.2 - 2:0 - 14.5 8.0 18.7.. . io.i , "25 -35 Methyl ethyl ketone...........'.................... '..........' Methyl.formate.......................................... -*: Methyl propyl ketone............................................ Natural gas,(variable). . --................... :..;. Naphtha (benzine)........................... v............... . ' 1.8 5.0 1.5 .4.3 . 1.1 ' 9.5 . .22.7. . 8.2 13.5 : 6.0 30 -2 20^-iio Naphthalene............................................................... Nonane..................................................... '................. Octane...........-........................... ........... Paraldehyde.......................................................' Pentane......................................................................... r.\'' 0.9 0.83 0.95 1.3' 1.4 7.8'.. 176 88 56 Air Contaminants 163 Table 6. Approximate Limits of Flammability of Single Gases and Vapors . In Air at Ordinary Temperature's and Pressures* (Concluded) ` Gas or Vapor Lower Limit Percent bt Volume . Upper Limit. . Percent bt Volume x' Closed Cupb Flash Point Fahrenheit Propane........................................................................ Propyl acetate ...'.................................................. ,, Propyl alcohol............................................................ Propylene..................................................................... Propylene dichloride............................................... Propylene oxide......................................................... Pyndine........................................................................ Toluene (toluol)........................................................ Vinyl chloride..................... ................................. ... Water gas (variable)............................................. ; Xylene (xylol)........... ..................................... .......... 2.1 i:-8 2.1 2.0 . 3.4 ' 2.0 - 1.8 1.3 . 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 66 74 40 95 ' ' . 63 * 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). ' -. . . . .' . k Closed cup refers to the equipment used in flash point determinations. 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 33). 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 grains are fairly uniform in size within the range of 15 to 25 microns. Pollen grains can be removed from the air more readily than the particles of dust prevalent in outdoor air or produced by dusty processes, since the latter predominate in the range of O.l.to 10 microns in size. . . . Most grains are quite hygroscopic and therefore vary ini weight with the humidity. Illustrations and data oh individual pollen grains are available in the botanical literature." ` Geographical distribution ' of plants known to produce hay fever is also recorded.11 M 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 determin- fflg the number of grains in a measured volume of air,1*-17" 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 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 13 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 164 CHAPTER 8 1952 Guide ' 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 directlyby 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.19- "81 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." 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 product^, 'i; . ' .. ' REFERENCES ' '. ."`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). . f.Micremeritjcs, The Technology of Fine Particles, by J,.M. BallaValle (Pitman Publishing Corporation,. 1943).. -: * Atmospheric Pollution Due to Smoke, by A. C. Stern (Heating and Ventilating, May, 1945). . . .. . " ' . .' Atmospheric Pollution Due1 to Dust and Cinders, by A. C. Stern {Heating and Ventilating, July, 1945); .. , ' 4 Sootfall Studies for New York City, by J. Siegel and B. Feiner (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, September, 1945, p..495)` * 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 Eight, 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 {V. 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). 9 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). 10 Disposal of Refinery Wfistea, Section II: Waste Gases, Vapors, Sludges and Dusts (American Petroleum Institute, New York City, 1938). ' :' Air Contaminants 165 : 11 Offensive Trades, by David Ronald (William Hodge and Co., London, .1935). 11 Limits of Inflammability of Gases and Vapors, by H. F. Coward and G'. W. Jones (U. S. Bureau of Mines Bulletin No. 279, 1939).' ................... 14 Inflammation Limits and Their Practical Application in Hazardous Industrial Operations, by G. W. Jones (Chemical Reviews, Vol. 22, February, 1938). 14 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 and Rates of Pressure Rise, by P. W. Edwards and L. R. Leinbach (V. S. De partment of Agriculture Technical Bulletin No. 430, October, 1935). .. ' * Dust Explosion Hazards in Plants Producing or Handling Aluminum; Magnet sium, or Zinc Powder, by H. R. Brown (V. 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). . 18 Inflammability and Explosibility of Powders Used in the Plastics Industry, by I. Hartman, and J. Nagy (U. S. Bureau of Mines Report of Investigation No. 3751, May, 1944). * .. 19 Industrial Dust Explosions, by H. R. Brown (U. S, Bureau of Mines, Informa tion Circular No. 7309, January, 1945). ' 80 Proposed Code for the Prevention of Dust Explosions in the Plastics Industry (National Fire Protection Association, Boston, May, 1945). .V ' 11 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. : !' 88 An Introduction to Pollen Analysis, by G. Erdtman (Chronica BotanicA Go., Waltham, Mass., 1943). . .: 88 Pollen Grains, by R. P. Wodehouse (McGraw-Hill Book Co., New York,1935). 84 Atmospheric Pollen, by R. P. Wodehouse (Aerobiology, p. 8-31, Publication No. 17, American Association for the Advancement of Science, Washington, D. C., 1942). '8` Hayfever Plants, by R. P. Wodehouse (Chronica Botanica Co., Waltham, Mass., 1945). 8`-Hay Fever: A Geographical and Botanical Survey, by E. R. Squibb and Sons, New York, 1937. ` tecnmques for Appraising Air-Borne Populations of Microorganisms, Pollen and Insects (Phytopathology, Vol. 31, March, 1941, p. 201-225). 88 Apparatus for Determining the Pollen Concentration of the Atmosphere, by B. J. Cody, W. F. Kinney and N. A. Kerstein (Research Department, the Detroit Edison Company, Detroit). . 89 The Volumetric Incidence of Atmospheric Allergens, by O. C. Durham (Journal of Allergy, Vol. 14, September, 1943, p. 455-461). ' 80 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). 81 Air-Borne Fungus Spores as Allergens, O. C. Durham (Aerobiology, d. 32-47, Publication No. 17, American Associationfor the Advancement of Science, Washington, D. G 10X91 88 Sampling Devices, by H. G. DuBuy and A. Hollaender (American Journal of Medical Science, Vol. 209, February, 1945, p. 172-177). 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 Sciertce, 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.). . 166 CHAPTER 8 1952 Guide - !' Analytical Chemistry of Industrial Poisons, Hazards and Solvents, by M. B. Jacobs (Interscience Publishers, New York, 1941). . .. Bibliography of: Industrial Hygiene, 1900-1943 (V. S. Public,Health Service Bui- letin No. 289, 1945). . . -. Clouds and Smokes, by Wl E. Gibbs (P. Blakiston's Son & Co., Philadelphia, Pa., 1924). .. ... Determination and Control of Industrial Dust, by Bloomfield and DallaValle (If. 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, Boston, 1937). . . Industrial Dust, by Drinker and Hatch.(McGraw-Hill Book Co., New York, 1936). Industrial Health Engineering by A. D. Brandt (John Wiley & Sons, Inc., New YorInk,du19s4tr7i)a,l Hygiene. and Toxicology, edited by F. A. P. atty (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, etal (U- 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, New York, 1943).. . . .. .. Occupation and Health, two volumes (International. Labor Office, Washington, D.CTo.)x.icology and H, ygiene of Industrial Solvents, by Lehmann and Flury, trans' lated by Eleanor King and H. F. Smyth, Jr. (Williams and Wilkins, Baltimore, 1943)- CHAPTER 9 HEAT TRANSMISSION COEFFICIENTS OF BUILDING MATERIALS Heat 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; Water Vapor and Condensation; Vapor Transmission; Condensation Control 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 walls 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, (he overall coefficient of heat transmission. 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 combinations 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 (air to air); the time rate of heat flow expressed in Btu per (hour) (square foot) (Fahrenheit degree temperature difference between air on the inside and air on the outside of a wall, floor, roof or ceiling).- The term is applied to the usual .combinations of materials, and also to single materials, such as window glass, and includes the,surface conductance on both sides. 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 perpendicular to the area. Its value is expressed in Btu per (hour) (square foot) (Fahrenheit degree per inch of thickness). Materials are considered homogene ous 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 material from one of its surfaces to the other per unit temperature difference between the two surfaces. Its value is expressed in Btu per (hour) (square foot) (Fahrenheit degree). The term ts applied to specific materials as used, either homogeneous or heterogeneous. ,f-- film or surface conductance; the time rate of heat.flow between a surface and the surrounding air. Its value is expressed in Btu per (hour) (square foot of surface) (Fahrenheit degree temperature,difference). Subscripts! and o are used to differen tiate between inside and outside surface conductances, respectively. a = thermal conductance of an air space; the time rate of heat flow through an air space per unit temperature difference between the boundary surfaces. Its value is ex pressed in Btu per (hour) (square foot of area) (Fahrenheit degree). The conduct ance 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. R = thermal resistance. Its value is obtained from the reciprocal of heat transJer as expressed .by U, k, C, f ora. , It is expressed in (hours) (square feet) (Fahren heit degrees) per (Btu). For. example, a wall with a U value of 0.25 would have a .. .......... ' ' ' ' '167 ' ' "" ' ' ' '' ' 168 CHAPTER 9 1952 Guide 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 = Ri -+- Rt 4" Ri + 4 ... "i Ro - . (1) where,- Ri + Rt, etc., are the individual resistances of the wall components. ' -- ET = total resistance. ' ' '' For a wall of a single homogeneous material of conductivity k and thickness x, with surface coefficients/i and/0, . " 1 - . , 1 X ` 1 * ' / +/. <3) Heat Transmission Coefficients of Building Materials 169 . 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 method* is generally used. Tables 1 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 Fig. 1. Typical Variation op Thermal Conductivity with Density--for Fibrous'Material. Then by definition, U = l/R-t For a wall with air space construction and consisting.of two homogeneous materials of conductivities: h and fcj, thicknesses Xi and **, respectively, arid separated by an air space of conductance a, Rt =.7'+f /i k, a + kt /,, (3) and - U = 1/Rt In the case of types Qf 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 k. The resistance of the section 1/C.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. The determination of the fundamental conductivities and conductances requires considerable skill and experience to obtain accurate results. It with Mean Temperature 1 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. 1. 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 in Fig. 2. Thermal Conductivity of Soil The following statements are based largely on results of a study8 made in the Engineering Experiment Station, University of Minnesota, and pub lished in Bulletin 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 tots 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 degree of influence of temperature depends upon whether it is above or below frees- 170 , , CHAPTER 9 1952 Guide Table 1. Conductances (O') fob Surfaces and Air Spaces ' AU conductance value* expressed in Btu per {hour) {square foot) {Fahrenheit degree temperature difference) .. >. . . Section A. Surface Conductances for Still Alra , ____________ - . . . Surface Emissivity . of Surface . .. of Heat Flow : e - 0.83 c - 0.05 . - Vertical;:'.:--------------- ........------------:-- . Upward' Downward . 1.95 1.21 1.52* . 1.16. . 0.44' 1 . 0.74 Section B. Conductance of Vertical Spaces at Various Mean Temperaturesb Mean Temp Fahr Deg Conductances of Aik Spaces foe Various Widths in Inches 0.128 0.250 0.364 0.493 0.713 1.00 1.500 20 . 30 - 40 50 60 70 80 90 100 110 120 130 140 150 300 2.385 2.470 2.560 2.650' 2.730 2319 2.908 2.990 3.078 3.167 31250 3.340 3.425 1370 1.425 1.480 1335 1390 1.648 1.702 1.757 1.813 1370 1.92S 1.980 2.035 2.090 1.180 1334 1388 1340 1390 1.440 1.492 1.547 1.600 1.650 1.700 1.750 1300 1352 1.100 ' 1.148 . 1.193 1.242 1.295 1340 1390 1.433 1.486 1.534 1380 1.630 1.680 1.728 1.040 1.080 1.125. . 1.168 1310 1.250 1395 1340 1380 1.425 1.467 . 1310 1.550 1392 1.030 1.070 1.112 : 1.152 1.195 1340 1380 1320 1362 1.402 1.445 1.485 . 1330 1.569 1.022 1365 1.105 1.149 1.188 1328 1370 1310 1350 ' 1392 1.435 1.475 1319 1359 Section C. Conductances and Resistances of Air Spaces . Faced on One Surface with Reflective Insulations Location and Position of Aia Space Direction OF . Heat Flow TempDiff Fahr Dbg Winter Summer Conductance* (O No. of Air Spaces 23 Resistance* - No. of Air Spaces 1 23 Rafter Space (8 in.) Horizontal Horizontal ' 30 deg slope 30 deg slope 304eg elope Down Up Down Up Down ' ' Up Down Up 45 45 45 45 25 25 25 25 0.10 037 0.09 034 0:15 035 0.13 033 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 .435 1439 538 16.67 635 10.00 5.88 11.11 7.14 Stud Space &H in.) Vertical - 80 034 234 40 033 0.13 . 435 _ 739 Vertical 15 032 3.13 20 0.18 0.11 5.56 9.09 Vertical* 30 0.46 2.17 8 Radiation and Convection from Surfaces in Various Positions, by G. B. Wilkes and C. M. F. Peterson (A.S.H.VJ0. Transactions, Vol. 44, 1938, p. 613. * ' 'b 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.VJ3. 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). 4 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 rafterandstudspacesare divided into equal spaces. / 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. 9 Radiation and Convection Across Air Spaces in Frame Construction, by G. B. Wilkes and C. M. F. Peterson (A.S.H.V.E. Transactions, Vol. 43, 1937, p. 351). ` The recommended surface conductance for calculating beat 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 were de rived from Fig. 4, which was based on tests conducted at the University of Minnesota, and apply to vertical surfaces. Heat Transmission Coefficients of Building Materials 171 Table 2. -Conductivities (ft) and Conductances (C) of Building and * : Insulating Materials These constants are expressed in Btu per {hour) (square foot) (Fahrenheit degree temperature different*). Conductivities {k) are per inch thickness and conductances.(<7) are for thickness or ' construction stated, not per inch thickness. '' ; '.c Material , Description "P (z* D o B B -' J S i 0 "o u Conduct Q B ivity or Conduct Resistance a ance < a. Per' For 1 Inch Thick h 2 Thick ness (*> (O ness Listed * a S G) G) A u th o r ity BUILDING BOARDS (Non-Inbulating) i........... -t. - Compressed cement and as bestos sheets........................... Corrugated asbestos board.. Pressed asbestos mill board.. Gypsum board--gypsum between layers of neavy paper......................................... I in. gypsum board................ 1 in. gypsum board................. t in. gypsum hoard................. 118 20.4 60.5 62.8 63.5 119 110 86' 70 90 FRAME OON8TRUC- TION COMBINA- TION8........ ................ . 1 8n. fir aWthing nnH hnflj. 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......... YeQow pine tap aiding........... - 80 20; 20 16 4.1 0.48 0.84 1.41 0.86 0.50 0.82 0.85 1.28 m i .ig 2 2 0.24 2.08 1.19 0.71 - i\ 0.27 0.85 0.88 (3) 0) 1.16 (4) 2.00 1.22 1.18 0.78 (4) (4) 8) MASONRY,MATERIALS Common yellow clay brick8: One tier yellow common clay bride, one tier face brick, approx. 8 in. thick8: _ _ _ _ Clay Tils, Hollow......... 2 in. Tile; 1 in. plaster both sides............................................ 4 in. Tile, ) in. plaster both sides........................................... 6 in. Tile, | in. plaster both sides........................................... 8 in. Tile, average of 8 types (Walls No. 59, 63, 64, 66, 67. 90, 91. 92)................... 12 in: Clay t3e wall: 8 in. x 5 in. x 12' in. and 4 in. x 5 in. x 12 in.8......................... 120.0 110 127.0 100 124.3 105 - /- . oeo _ 0.20 0.21 _ 0.77 1.00 0.60 _ 0.47 _ 0.52 - 0.26 - _ 1.30 (4) 1.00 f.67 2.18 O) (3) (2) 1.92 (4) 8.84 (4) Authorities: . * National Bureau of Standards, tests based on samples submitted by manufacturers: - 1 A. C. Willard, L. C. Lichty and L. A. Harding, tests conducted at the University of Illinois. /'' . * d. C. Peebles, tests conducted at Armour Institute of Technology, basedon samples submitted by manufacturers. ^ . . ............................. * F. B." Rowley, et ai, tests oonducted-at the University of Minnesota. ' .t * A.8.H.VJS. Research Laboratory. .. 1E. A.-Allcut, 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). n _ Heat Transmission Through Insulation as Affected by Orientation of Wall, by F. B. Rowley and C. Lund (A3.H.V.E. Transactions, Vol. 49, 1943, p. 331). .. ... * The Effect of Convection in Ceiling Insulation, by G. B. Wilkes and L. R. Vianey (AJ3.H.V.E. Trans actions, Vol. 49r 1943; p. 196). .: See AB.H.V_B. Research Report No. 915--Conductivity of Concrete, by F. C. Houghten and Carl Gutberlet (A3.H.VE. Transactions. Vol. 38, 1932, p. 47). . . See Beating, Ventdating and Air Conditioning, by Harding and Willard, revised edition, 1932. See BMSlS, 17. S. Department of Commerce, National Bureau of Standards, Washington, D. C. '' ,t.a Hoofing, 0-15 in. thick (1.34 lb per square foot), covered with gravel (0J3 lb per square foot), combined uuckneaa assumed 0.25. " 172 CHAPTER 9 1952 Guide kTable 2. Conductivities ( ) and^ConductAncest^-C) of Building'and Insulating Materials--Continued These constant are expressed in Btu per (four) {square foot) {Fahrenheit degree temperature difference). Conductivities (k)areper inch thickness and conductance* (C) are for thickness .or construction stated, not per inch thickness. , -; _ o Conduct- P o 0 IVTTY OB Conduct- Resistakce 9' - . aH akce Material Description n. w *4 3 zH G | H s S Per 1 Inch Thick- h (*> (C) Thick ness ness Listed s 0 (0 (s) < MASONRY MATERIALS '. --(Continued) Concrete.. ...................... Sand and gravel aggregate. various ages and mixes.. -- Sand and gravel aggregate.. 142 Steam treated limestone Pumice (Sued in Cali* 97 74.6 fornia) aggregate0........ 66.0 Expanded Burned clay ag- 69.9 Burned clay aggregate.......... . 67.1 Blast furnace ring amepite. 76.0 Expanded .vermlcuEte ag- 75 75 75 75 75 75 75 70 r 11.35 to 16.36 12.6 10.8. 4.9 -- __ 0.09 0.06 0.08 0.09 0.22 2.27 0.44 2.42 -- ; 0.41 . 2.28 2.86 .1.6 0.44 0.36 0.63 _ __ __ -- (S) (f4if) (4) (4) (4) (4) (4) (3) 11 1 ; : 8 In. Concrete Blocks . 13 In. Concrete Blocks Expanded .vermiculite^. ag- .26.7 Expanded vermiculite ag- gregate....................................... 35 90 Expanded vermiculite ag- 60 . 90 Expanded Vermiculite ag- gregate, 1:9.4 mix.. ..___ .26.3 119 Expanded Vermiculite ag- gregate, 1:2J) mix.................. 46.6 119 Perlite aggregate. 1:10.3 mi*. 24.4 119 Perlite aggregate 1:2.9 mix... 47.6 119 76 75 Cellular concrete...................... 40.0 75 Cellular concrete....................... 50.0 75 Cellular concrete................. Cellular concrete....................... Air-cooled slag aggregate____ Air-cooled slag aggregate.... .60.0 70.0 124.2 124.9 76 76 119 119 8 in. three oval core, sand and gravel aggregate......... 8 in. three oval core, crushed limestone aggregate?........... 8 in. three oral core, cinder . aggregate................................ 8 in. three oval eore, burned 8 in! three" oval eore, expanded blast furnace slag 8 in. three oval core, aircooled slag aggregate........... 126.4 40 134.3 .40 86.2 40 67.7 40 40 -- 40 0.86 1.10 -- r 1.18 0.91 0.97 1.60 0.75 1.45 2.6 1.06 1.44 1.80 2.18 5.3 6.9 -- __ __ __ __ -- -- -- -- 1.03 0.63 1.33 0.69 0.40 0.94 0.69 0.56 0.46 0.19 0.17 _ -- __, . _- __ __ __ -- ' . 0.90 -- -- 0.86 .. r- 0.58 .. -- 0.50 1.11 1.16 1.73 2.00 0.49. -- 0.68 ;2.04 -- ' 1.47 0) 0) () (1) hi (3) (3) hi M (h1i) (4) (41 .(4) (4) (4) (4) 3 12'in. three oval core,'sand and gravel aggregate?......... 12 in. three oval core, cinder 124.9 ' 40 ; >1' 86.2 40 a 12 In.- three oval core, burned clay aggregate___ 78.7 40 -**r- See footnotes oh first page of Table 2. -- - 0.78 0.53, 0.47 -- . 1.28 (4) 1.88. (4) 2.13 (4) HeatdTransmission Coefficients of Building Materials 173 Table ,2.: Conductivities (fc) and Conductances (C) of Building and ' Insulating Materials--Continued 1 . These ametante are expreeeed in Biu per (hour) {square foot) (Fahrenheit detree temperature difference.) Conductivities (A) are per inch thickness and conductances (C) are for thickness or construction stated, not per inch thickness. _ 0 Conduct-; O O O IVITY OB Conduct- Resistance to ANTE a Material . Description 0 Per For wg Inch Thick- e >t* 3 H (*) <0 Thick neas ness Listed 50 2< aa (0 (e) QS < MASONRY MATERIALS --(continued) .Gtpbum................................... PLASTERING RIALS MATE- 3 in. solid gypsum partition tile............................................. 3 in. three cell gypsum partition.tile................................ 4 in. three dell gypsum par- 874 percent gypsum.. 124 51.2 74 2.41 -- 0.74 0.60 1.66 Gypsum plaster........................ __ Gypsum plaster, { in. thick. __ Cement plaster...................... __ Wood, lath and plaster, to__ Gypsum plaster and expanded vermiculite, 4 to Gypsum vermiculite plaster Mix. 100 lb:. 2 cu ft............ .. Mix. 100 lb: 3 cu ft............... Gypsum perlite plaster Mix. 1001b: 2 cu ft .........; 39.9 40.7 49.1 42.5 Gypsum sand plaster Mix. 100 lb: 200 lb................ 104 Mix. 100 lb: 300 lb . ;., 107 Insulating plaster 0.9 . in. thick applied to | in. gyp". 54.0 __ Z.30 73 . 8.00 70 __ 75 0.85 63 .1.84 64 -6464 1.35 53 5.55 52 5.77 75 __ 8.80 2.50 __ __ 1.07 0.42 --' 0.60 0.30 : 0.13 . 1.18 0.54 0.61 0.60 0.74 0.18 0.17 HOOFING : :: j< ' Asbeetos shingles: ................ Asphalt, composition or prepared............. ;.................... Built-up roofing, bitumen - or frit, gravel or slag 65.0 70.0 70.0 _ Wood shingles___ ...................... -- 75 - 6.0 _76 -- 6.5 75 6.5 __ 10.00 __ -- 1.28 - 0.75 0.10 WOODS : 20.0 0:58 1.72 - 8.8 90 0.38 -- 2.63 7.3 90 0.33 -- 3.03 California redwood, 0 % 28.0 75 28.7 Ml 0.67 __ 1.43 1.49 Douglas fir, 0 % moisture.. 34.0 75 0.67 -- Eastern hemlock, 0 % 1.49 moisture............................... 30.0 . 75 0.76 Long leaf yellow pine, 0 % -- 1.32 40 0 75. 0.86 Mahogany ..:........................... 34.3 -86 0.90 _ 1.16: , 1.11 I Hard maple, 0 % moisture. 46.0" 75 1.05 -- 0.95 _44.3 .86 Maple, across grain.................. 40.0 75 1.10 1.20 0.83 -i Norway pine; 0 % moisture. 32.0 75 0.74 -- 1.35 Red cypress, 0 % moisture. 32.0 75 0.79 -- 1.27 Red oak, 0 % moisture.. 48.0 75 1.18 -- Short leaf yellow pine, 0 % 0.85 moisture................................. 36.0 75 0.91 -- 80ft elm, 0 % moisture.. 34.0 75 0.88 -- 1.10 1.14 -- 1.35 1.67 (4) (4) (4) (4) 0.11 0.40 (4) (*) (4) 0) __ (1) G) <>! (0 __ (1) 0) 0.93 0) 0.17 0) 0.15 0.15 . (3) 0) 0) 0.78 -- -- Hi a! a) (4) (1) -- (4) (4) _ M) (1 (4) fl) _ (3) _ (4) _ t) -- (4) _ (4) -- (4) .See footnotee.on first page of Table 2. 174 CHAPTER 9 1952 Guide Table 2. Conductivities (k) and Conductances (C) op Building and' . Insulating Materials--Continued These constant* are expressed in Btu per (hour) (square foot) (Fahrenheit degree* temperature difference.) Conductisities (k) are per inch'thickness and conductances'(O are for thickness or" . - . construction stated, not per inch thickness. - ' r ' Matebial '' ; . Description 1? t> O 0. n i a a V Conduct- Q a a IVITT OB Conduct ance Resistance < Per 2 -Inch Thick- H (*) ( Thick ness ness listed sO < a S G) G) < WOODS--(continued) Soft maple, 0 % moisture.. 42.0 75 0.95 *1.05 : ___Sugar pine. 0 % moisture.. 28.0 75 0.04 -- 34.3 - 80 0.90 1.50 1.04 West coast hemlock, 0 % Yellow pine................... Shavings, various from 31.2 80 0.78 1.00 12.0 * 90 ' 0.41 _ -- 1.28 1.00 2.44 -- -- - _ -- !41 (4) 0) (1 (3) 0) SHavinxs.from maple beech and Birch (coarse).............. 13.2 90 0.30 --- - - -- 2.78 in INSULATING : MATE- RTATifl Blanket ............ and Bat Chemically treated wood fiben held between layers Flax fibers between strong Chemically treated hog hair 3.02 4.00 J. - between kraft paper . .. 5.70 Chemically treated hog hair between kraft paper and asbestos paper........................ 7.70 Hair felt between layers of 11.00 . Kapok between burlap or 1.00 Stitched and creped ex- pending fibrous blanket... 1.50 Paper and asbestos - fiber with emulsified asphalt Cotton insulating bat............. 0.875 -' 6.25 4.50 Short Staple Linters, 2.45 1.60 0.85 0.05 Felted cattle hair...................... 13.00 11.00 Felted hair and asbestos----- 7.80 Ground paper between two ' layers, each | in. thick made up of two layers of kraft paper (sample J in. thick)....................................... 12.1 4.5 __ 70 0.25 90 0.28 71 0.20 71 0.28 75 0.25 90 0.24 70 . 0.27 94 0.28 72 0.24 90 0.25 90 0.24 90 0.24 90 0.20 90 0.29 90 0.30 90 0.20 90 0.26 90 0.28 75 _ 0.27 __ _ _ -- __ -- -- -- -- -- -- 0.40 _ 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 _ 3.70 _ Made from sugar cane fiber.. 13.5 70 0.33 __ Made from hard wood fibers. 15.20 70 0.32 -- Made from wood fiber............ 15.90 72 0.33 -- 15.00 70 0.33 -- Made from wood fiber .. - -- 52 0.33 -- Made from wood fiber...... 15.20 -- 0.33 -- Made from wood fiber......... 10.90 90 0.34 -- Made from licorice root. .. . )6.1 81 0.34 -- 3.03 3.12 3.03 3.03 3.03 3.03 2.94 2.94 i in. insulating boards with out 8pedal finish^ (eleven 16.5 --90 0.33 3.03 to 2i:8 to -- 0.40 -- to 2.50 1 in. insulating board........... 13.2 -- 0.34 --: . 2.94 _ -- ` __ __ -- -- -- --. -- -- 2.50 _ _ -- -- -- -- -- -- -- ' (8) 0) 0) G) (3) (1) (3) (1) (3) ffil!j fi! h1) (1 0) (!) O' ; (3) 2 f(3i!) fi)! fi (3) a) (4) See footnotes on first page of Table 2. Heat Transmission Coefficients of Building Materials 175 Table 2. Conductivities (fc) and Conductances (C) op Building and . . Insulating Materials--Concluded . 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, not per inch thickness. '- ' ' Material ' Description ? &. 'D o - 05 fib 3 h 1 N Q "wo G M Conduct^ IVlTY OB , Conduct- . ' ANCB 3 Resistance w -fib Per For 3 Inch Thick ' -H -z (i) (C) Thick .- ness- ' s ness . Listed. o G) G)3 s D s -< INSULATING MATERI ALS--(Continued) Loose FillTtpe................ Made from ceiba fibers........... Made from ceiba fibers.......... Chemically treated wood . fibers.......................................... Fibrous material made from dolomite and silica.............. Fibrous rnftternl made from slag............................................ Redwood bark'............. ,............ -Redwood bark............................ Glass wool fibers 0.0003 in. to 0.000 in. in diameter.... Granular insulation made from combined silicate of lime and alumina .. .* Expanded vermiculite............ Regranulated cork about A in. particles.. ___ Hand applied granular mineral wool 2 in: to 6 in." thick,' horixontal posi tion. No covering....... 4 in. machine blown granu lar mineral wool, horizon tal position*. No eover- - ing.:.:........................... :..... Rock wool............................. . 1.90 1.60 4.0 1.50 9.40 3.00 5.00 1.50 4.20 7.0 8.10 6.05 to 7.13 5.74 10.0 75 75 75 75 103 90 75 75 72 70 90 90 Slab Insulations.................. Corkboard, no added binder. 14.0 90 Corkboard, no added binder. 10.6 90 Corkboard, no added binder. 7.0 90 Corkboard, no added binder. 5.4 90 Corkboard................................ 8.7 Corkboard, asphaltic binder. 14.5 90 Chemically treated hng hair with film of asphalt. 10.0. 75 Sugar cane fiber insulation blocks encased in asphalt membrane............................ .13.8., 70 Made from shredded wood and cements___ ;................... 24.2 72. Made from shredded wood and cement......................... Ueliulsr *!**.... ......... 29.8 9.0 __ 75 Cellular glass............. ................ 9.0 50 0.23 0.24 0.28 0.27 0.27 0.31 0.20 0.27 - 0.24 0.48 0.31 0.30 to' 0.33 0.30 0.27 0.34 0.30 0.270.25 0.29 0.32< __ __ __ __ __ 0.28 0.30 -- 0.46 - -- 0.77 0.42 0.40 __ -- -- 4.35 4.17 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 8.57. 3.33 2.17 i .so 2.38 2.50 - (3? (3) (4) (3) (1) 8! (3) (3) - 0) Ml __ . ._ - . (1) nin Jo 0) (3) . --- -_ (3) (3) - (4) us . fn .-- - See footnotes bn first page of Table 2. ing. For increases of moisture content exceeding about 6 to 12 percent, the conduc tivity of frozen soil becomes progressively greater than that of the unfrozen soil. Effect of Density. Density affects the thermal conductivity of a soil in about the same manner for all soils, at any moisture content, and for either the frozen or un frozen condition. On the average, each one pound per cubic foot increase in dry density increases the thermal conductivity by about 3 percent. ' Effect of Moisture. An increase in moisture content, up to the point of saturation, causes an increase.in thermal conductivity. The rate of increase is indicated by the following values. Average conductivities, in Btu per (square foot) (hour) (Fahren heit degree per inch), of four sands at a density of 110 lb per.cu ft were: 6.8 at 2.5 percent moisture, 8.9 at 5 percent moisture, 11.2 at 10 percent moisture. Five soils of a fine texture at a density of 100 lb per cu ft, gave average conductivities of 6.7 at.10 percent moisture, and 9.5 at 20 percent. Thus, the doubling of moisture con 176 CHAPTER 9 1952 Guide tent within the ranges cited increases the conductivity by approximately 30 or 40 percent. At higher moisture contents the percentage increase would be less. ' Effect of Soil Characteristics. The thermal conductivity of the soil, at a given density and moisture content varies in general with the texture of a soil; being rela tively high for coarse-textured soils and relatively low for fine-textured soils. The mineral composition of the soils also affects the conductivity. Quartz tends to give high values, whereas minerals such as plagioclase feldspar and pyroxene, which are constituents, of basic rocks tend to give low values of thermal conductivity. These points are illustrate^ Ijy the values in Table 3 which lists seventeen soils in approxi mate order of their magnitude of thermal conductivity from greatest to least for seven different density-moisture content conditions. Some of the . values in this table have been determined by extrapolation and are consequently approximate. Blank spacefill the table indicate that the density or moisture content, or both, are such that na.tests were possible for that condition or that no tests were sufficiently TablP 3. Thermal Conductivity (4) Values or Soils in Approximate Order op Decreasing Values" h. . Mean Temperature--iO F %Moist'dbe Content-- Son. No. Son/Designation 4 4 4 ! 10 | 10 | to | 20 Dby Dknsity-lb psb CO FT 100 no 120 90 no 90 100 P4714 P4703 P4701 P4709 P4G04 P4601 P4705 P4706 P47U P4704 P4713 P4502 P4503 P4708 P4602 Fine Crushed Quarts 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 Loam 12.0 16.0 11.6 16.0 10.0 14.0 . 8.5 8.6 1101..50 22.0 13.5 6.0 .5.5 5.0 9.04= 7.5 7.5 6.6 6.0 13.0 0.5 10.0 9.5 7.0 4.5 6.5 4.5 5.5 - 4.5 6.0 4.04= P4710 ' P4505 Fairbanks SUty Clay Loam . Northway Silt Loam : " * = Btu per {square foot) (hour) (Fahrenheit degree per inch). 15.0 13.6 134= 10.0 8.5 7.5=fc 5.5 9.04; 5.0 9.04: 5.0 9.04= 4.0d; 7.04= 8.0 10.0 7.5 10.0 7.5 9.6 6.04= 7.04= 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 tivity at a given condition. Sandy loam soils are midway in the table and fine grained soils such as clay and silt loam are last. Estimating Thermal Conductivity. The four diagrams of Fig. 3 are presented to aid in the estimate of the thermal conductivity of any soil. . Two of the charts are for sands or sandy soils, and two for silt and clay soils. One of the diagrams for each type of soils is for the frozen, and the other for the unfrozen condition. It is expected that these charts will give conductivity values with a precision of 25 per cent. The effect of such factors as density, moisture content, freezing, or texture may be easily approximated by use of these graphs.. : Specific Heat of Soils Tests to determine specific heat were run on twelve soils. On five of the soils, tests were made at three or four mean temperatures varying from about 10 .to 140F. The specific heat values of all twelve soils varied by only a small amount (about 0.01), and averaged 0.19 at 140 F. The specific heat values of the soils decreased with a decrease in temperature. The average value at zero F would be about 0.16. Values at temperatures Heat Transmission Coefficients 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 convection and conduction 's Fig. 3. Determining Thermal Conductivity op Soils prom Density and Moisture Content . 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 23.) The convection part of the surface conductance is affected markedly by 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 178 t CHAPTER 9 1952 Guide recent tests' on smooth surfaces; show that surface length also affects sig 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 to 19, 1,65 has been selected as an average inside surface conductance; and 6.0 as ah 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 he used for low emissivity surfaces such as bright metal. Values of U 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 conductance. In special cases, where surface conductances become important factors in the overall rates of heat transfer, more selective coefficients may be Table 4. Variation in Surface Conductance Coefficient with Different Temperatures of Surrounding Surface Surrounding Surface Temperature 75 F . 70 F 69 F 60 F 60 F Convection--Btu per (hr) (sq ft).. 6.6 Radiation-- Btu per (hr) (sq ft)... 4.4 Total--Btu per (hr) (sq ft)............. 11.0 6.6 8.6 15.2 6.6 9.6 16.2 6.6 17.0 23.6 6.6 24.9 31.5 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 emis- sivities, 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 } 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 6 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 metalswhich 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 T, 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. 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, hor 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 *hrectly for the long wave length radiation corresponding, to average room 180 CHAPTER 9 1952 Guide Table 5. ' Conductivities (ft) and Condutances (C) Used in Calculating Heat ( )UTransmission Coefficients in Tables 6 to 19 ' 1 These constant* are expressed tn Btu per (how) (square foot) (Fahrenheit degree temperature difference). ., Conductivities (k) are per inch thickness and conductances (C) are for thickness or , ' . . construction stated, not per inch thickness -' ' .. Conductivitt| [Conductance! Rebzstancb Description Per Inch| ! Thick- 1 For Thicki, (k) (O ness ness - tasted (D g) AIR SPACES ` BipomuniAdteud..b..y..O...b.d..z.n..a..b.t..M...a.-. Vertical, J in. or more in width. Boundsd btAluminum Foil. Vertical, I in- or more in width. 1.10 0.40 0.91 2.17 EXTERIOR FINISHES (Frame Walls) Bbick Veneer ........................ Stucco (1 in.).................. . Wood Shinsues...................... Yellow Pine Lap Siding. .. 4 in. thick (nominal).. 2.27 0.08 0.78 0.78 INSULATING MATERIALS Aluminum Foil...................... Bats and Blankets............. COBKBOABD........................................ Insulating Board. .............. Mineral Wool........................ VEBM2CULIT3.................................. See Air Spaces............................................. . Made from mineral orvegeteble fiber or animal hair, enclosed or open. , Pure, no added binder.:*............... .Vegetable fiber............:------ '..................... Fiber made from rock, slag or glass.. Expanded........................................................ 0.27 0.30 0.33 0.27 0.48 3.70 3.33 3.03 3.70 2.08 INTERIOR FINISHES Composition Wallboabd .... Gtpbum Plaster...................... . Gtpbum Boabd (% in.)........... Gtpsum Lath (| in.) and Plaster................................. Insulating Boabd (1 in.) .... Insulating Board Lath () in.) and Plaster........... Inbulatxng Board Lath (1 in.) and Plaster...___ Metal Lath and Plaster .. Pltwood (3 in.)..................... Wood Lath and Plaster. -. A in. to 3 in. thick. . I..;..................... Plain or decorated.................................... Plaster thickness assumed 1 in.. Plain or decorated......................... - Plaster thickness assumed ) in... Plaster thickness assumed ) inA. Plaster thickness assumed i in.'.. Plain or decorated............................. 0.50 3.70 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 Bbick........................................ Bbick........................................ Bbick........................................ Adobe, assumed 4 in._thick.......... Common, assumed 4 in. thick....... Face, assumed 4 in- thick................ Cement Mobtab. I......... 3 in. Clat Tile (Hollow' 4 in. Clat Tilb (Hollow, 6 in. Clat Tile (Hollow' 8 in. Clat Tile (Hollow: 10 in. Clat Tile (Hollow 12 in. Clat Tile (Hollow' 16 in. Clat Tilb (Hollow) light weight aggregate^................... . Concrete............................ Concrete............................. ... Sand and gravel aggregate............. 3 in. Concrete Blocks____ Hollow, cinder aggregate................. 4 in. Concrete Blocks____ Hollow, cinder aggregate................. * 8 m. Concrete Blocks____ Hollow, gravel aggregate................ 12 in. Concrete Blocks____ Hollow gravel aggregate................... 8 in. Concrete Blocks____ Hollow, cinder aggregate................. 12 in. Concrete Blocks Hollow, cinder aggregate............ 8 in. Concrete Blocks .:... Hollow, light weight aggregate.. 12 in. Concrete Blocks.......... Hollow, light weight aggregator.. Gtpsum Fiber Concrete. .., 871 percent gypsum and 12) percent wood chips...... .................................. 3 in. Gtpsum Tilb................. Hollow................................................. ... 4 in. Gtpsum Tile................. Hollow...................................................... Stucco....................................... Tils and Terbaxzo............... For flooring.. Stone................................................ 2.50 12.00 1.66 12.50 12.00 12.50 0.89 12.25 1.28 1.00 0.64 0.60 0.58 0.40 Q.31 1.: 1.00 1.00 0.80 0.60 0.53 0.50 0.47 0.61 0.46 0.40 0.08 0.08 0.08 0.08 1.12 0.80 0.43 0.78 1.00 1.57 1.67 1.73 2.50 8.23 0.78 1.00 1.00 1.25 1.66 1.88 2.00 2.13 1.64 2.18 Conductance values for horizontal air spaces depend on whether the heat flow is upward or downward, but in most cases it is sufficiently accurate to use the same values for horisontal as for vertical airspaces. v - * Expanded slag, burned day or pumice. Heat Transmission Coefficients of Building Materials 181 Table 5. Conductivities (ft) and Conductances (C) Used in Calculating Heat' Transmission Coefficients (U) in Tables 6 to 19 ' These constants are expressed in Btu per (how) (square foot) (Parhenheit degree temperature difference.) ' Conductivities'(fc) are per inch thickness and conductances (C) are for thickness or . construction stated, not per inch thickness . - . - : CpNDUCTIVlTI ' J OR ' Resistance Conductance Material Description ; Per Tnnh For ` Thick Thick-, <i) (C) . ness ness Listed: G) G> ROOFING MATERIALS Asbestos Shingles................... Asphalt Shingles..................... Built-up Roofing................ Heavy Roll Roofing.............. Slate............................................... Wood Shingles........................... SHEATHING # Gtpsum () in.)............................ Insulating Board (if ns.)... Pltwood (A in.)........................ Fir ob Yellow Pine (1 in.). Fir, Plus Building Paper .. -- , SURFACES Ordinary non-refleetive materials. 15 mph Wind Velocity............ Ordinary non-reflective materials, vertical.......................................................... WOODS Fir Sheathing (1 in.) Build : . ino Paper and Yellow Pine Lap Siding.................... Maple or Oak............................. Yellow Pine or Fib............... ............... ..................: .*.................................. 10.00 -- __ -- 0.80 3.53 20l00 1.28 0.42 2.66 1.02 0.86 1.65 6.00 -- 0.10 -- __ 1.25 0.28 0.78 2.37 0.98 1.16 0.61 0.17 2.00 - 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 6 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 1952 Guide applied) will comply with the tabulated values. Exact conductivities or conductances for specific materials should be obtained from the maker. Insulating Materials >- In order to determine the benefit derived from the addition of insulating materials to a given construction, the overall coefficient ofheat transmis sion I7i of the insulated construction may be compared with the corre sponding coefficient' {/ without insulation. Attention is called to the necessity of applying the insulating material in accordance with the manu facturer's'specification ; The engineer must evaluate carefully the eco nomic 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 unsatisfactory results. _ . Tib Rods and Insulation Computed Heat Transmission Coefficients Computed overall heat transmission coefficients of many common types of building construction are given in Tables 6 to 20, inclusive, each coeffi cient being identified by a serial number, except in Tables 19 and 20: For example, the coefficient U of a brick veneer, frame wall with wood sheath ing and f-in. of plaster on gypsum lath is 0.27 (Wall No. 28-C in Table 6) and with 2 inches of blanket or bat insulation, the coefficient would be 0:097 (No. 49-B in Table 7). 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 transfer which state that in parallel flow the conductances are additive, while in series flow the resistances are additive. Likewise, in order to deter mine 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 1 and Fig. 5. As this wall was tested by the hot box method Heat Transmission Coefficients of Building Materials 183 at the University of Minnesota, a direct comparison can be made between calculated and tested values. ; -i Example 1: Calculate the coefficient of heat transmission U for wall as Bhown in Fig. 5. Wall construction consists of two 4-in. concrete walls separated by a 2$-in. space filled with insulation; J-in. diameter metal tie rods are imbedded a distance of 1 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 Fig. 5 the following paths of heat flow from plane A to plane F will be noted: ... 1. From A to B: One path through 3 in. of concrete. . . , 2. From B to C: Two'paths, (a) through 1 in. of tie rod, and (b) through 1 in, of concrete. , 3. From C toD: Two paths, (a) through 2J in. of tie rod, and (6) through 2} in. of insulation. . 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. . 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 made 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. . ' '' ' . 'i Parallel Flout. The conductances through the areas of parallel heat flow may. be determined as follows: 1. The area of each J-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 4 = 0.00048 sq ft of tie-rod to each square foot of wall area. Then from plane B to plane G, the conductance C, is - 0.00048 400 0.99925 12 C, ~lo~.x 7o + 1Fx Ti = 0192 + 11994 " 12189 A U1C u uisuiavitiu 11 Will yiailC KJ liU piailtJ . w 0.00048 400 0.99952 0.30 . . . : M + ir ><^- = 0.077 + 0.120 = 0.197 .. 3. For tie rod and concrete from plane D to plane E the conductance C> is ,, 0.00048 400 0.99952 12 Cl " To- x lo + ~uT x lo = 0192 +11994 = 12;186 . . -' Series Flow. After the conductance values have been determined, the total re sistance and U value can be determined as follows: ,, 1 x, 1 1.1 x, 1 IiT~fi+kl + cl + ct + d, + +f0 . . -, - ftx = -- + -- + -1-- + -- + ---- + -- + .1 1.65 12.0 12.186 0.197 12.186 12.0 6.0 ` Ri = 0.606 + 0.250 + 0.0821 + 5.076 + 0.0821 + 0.250 + 0.167 = 6.513 U= = 0.153 Btu per (hr) (sq ft) (F deg). . . . Ht 6.513 \ 184 CHAPTER 9 1952 Guide The Hot. Box test value, from' University of Minnesota, for this wall, corrected for a 15 mph -wind velocity, was U = 0.150 Btu' per (hr) (sq ft) (F deg). The error between the calculated and test values would be ; .. 0 153 01^ X 100 = 2 percent. 0.150 . ... - . If the effect of the tie rods were omitted from the calculations, the over all U value would be 0.103.. Although the percentage of area occupied by . 0.00048 ' .. the tie rods per square foot of wall area is -- X100 0.048 percent, the error between the calculated and test values would be 0.150 - 0.103 X 100 = 31 percent. 0.150 In making the calculations for values of U shown in Tables 6-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 i 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 lin. (S-2-S)................................. Min. .- 11 in. (S-2-S)................................ ly in. 2 in. (S-2-S)................................ If in. 21 in. (S-2-S)................................2f in. Nominal ' Actual 3 in.-fS-2-S)....... ;.............................2f in. 4 in. (S-2-S).................................. .3# in. Finish flooring, (maple or oak) i .. 1At 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. . 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, the combined coefficient from room air below the ceiling to exterior air can be calculated from the following formula: Heat Transmission Coefficients of Building Materials 185 ** U,, + nU, (4) and U = 1/Et where . U = combined coefficient to be used with ceiling area. Rt -- total resistance of ceiling and roof. U,, = coefficient of transmission of ceiling. Ur = coefficient of transmission of roof. n = ratio of roof area to ceiling area. (5) 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 Ut and U,, 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 Ut. Where attic wall areas are large, it is preferable to estimate the attic temperature as illustrated in Chapter 11, and calculate the heat loss through the ceiling by multiplying the value of U,, for the ceiling by the difference in temperature above and below the ceiling. Basement Floor, Basement Wall and Concrete Slab Floor Coefficients The heat transfer through basement walls and floors to the ground is dependent on the temperature difference between the air within and that of the ground, on the material 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. Relearch Laboratory indicate a heat flow of approximately 2.0 Btu per (hr) (sq.ft) through an uninsulated contrete 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 (he 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 11. 186 CHAPTER 9 19S2 Guide Table 6. Coefficients of Transmission (l/) of Frame Walls These coefficient* are expressed in Btu 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 15 mph. ' - No Insulation Between Studs* (SBe Table 7) EXTERIOR FINISH INTERIOR FINISH TYPE OP SHEATHING Gtfotm 04 w. THICK) PitWOOD (VfeDI. thick) Wood/ (H6 ra. thick) Bldo. Patch Instil- ATtKQ Board ("/6 m. thick) 3 B 2 1 Aa CD /BfiATtUMG Meta! Lath and .................... Gypsum Board (H in.) Decorated............. - Wood Lath ahd Plaster... Gypsum Lath (H in.) Plastered*......... .-........: Plywood (H InT) Plain or Decorated--............ Insulating Board (M In.) Plain or Decorated... Insulating Board Lath (H in.) Plastered*--__ Insulating Board Lath (1 in.) Phatoed*_____ 023 022 021 0.31 0.30 0.23 0.22 0J7 032 . 032 031 030 030 033 032 0.17 036 030 026 . 030 035 0.19 035 0.19 0.24 0.19 0.19 .016 019 0.15 015 012 1 2 3 4 S 67 8 Wood* SsntaLxs /TWA Metal Lath and Plaster*.. 0.25 035 036 017 9 Gypsum Board (H in.) 1 0.25 035 038 0.17 10 wood Lath and Piaster-- 0.24 034 035 016 11 Gypsum Lath (H in.) Plastered*-- 0.24 034 035 016. 12 Plywood (H in.) Plain or Decorated- 0.24 034 0.24 016 13 Insulating Board (M in.) Plain or Decorated--. 0.19 0.19 0.19 014 14 Insulating Board Lath (H in.) Plastered*____ 0.19 0.18 0.19 013 15 Insulating Board Lath (1 in.) Plastered*_____ 0.14 0.14 015 0.11 18 /HCATKtNa) Stdoco /TUFA StVCCO SiteATKlMGJ Metal Lath and Plaster*...TM______ 0.43 Gypsum Board (H in.) Decorated., 0.42 . wood Lath and Plaster- 0.40 Gypsum Lath (K in.) Plastered*TM...... 0.39 Plywood (H in.) Plain or DecoratedTM............. 0.39 . Insulating Board (M in.) Plain or Decorated-- 0.27 Insulating Board Lath M in.) Plastered*. 0.26 Insulating Board Lath.tl in.) Plastered*- 0J9 0.42 0.41 039 039 038 037 036 019 032 031 030 030 039 . 032 032 . 016 033 033 032 022 032 0.18 0.17 0.14 17 18 19 20 21 22 23 24 . Bbicx Vhkekb* /TffPA ' ht-ICK Metal Lath and Plaster*_________ 0.37 036 038 031 25 Gypsum Board (H in.) Decorated- 0.36 036 038 031 28 Wood Lath arid Plaster- 0.35 034 037 030 27 Gypsum Lath (Hin.) Plastered*---------. 034 034 0.27 030 28 Plywood (M in.) Plain or Decorated_____-- 034 033 037 030 29 Insulating Board (K in.) Plain or.Decorated--. 0.25 035 031 0.17 30 Insulating Board Lath (V$ in.) Plastered*, 034 034. 030 0.16 31 insulating Board Lath (I in.) Plastered*-- 0.18 018 015 033 32 /HttfHIWG (Sec text p. 182.- . . * Coefficients not weighted; effect of studding neglected. .. .. . Plaster assumed X in. thick. ' . :. e Plaster assumed H in. thick. a . - 4 Furring strips (1 in. nominal thickness) between wood shingles and all sheathings except wood. * Small air space and mortar between building paper and brick veneer neglected. .. . / Nominal thickness, 1 in. . ....... Heat Transmission Coefficients of Building Materials 187 Table 7. Coefficients of Transmission ({/) of Frame Walls with Insulation .. , Between Framing0 b . , ... Coefficients are expressed in Btu per (hour) (squarefoot) (Fahrenheit degree difference in temperature between .............. the air on the two sides), and are baaed on an outside wind velocity of 16 mph, _ COEFFICIENT WITH INSULATION BETWEEN FRAMING N umber COEFFICIENT ' WITH NO INSULATION BETWEEN FRAMING Mineral Wool ob Vegetable Fibers in Blanket ob Bat Fobmc (Thickness below) 1 IN. 2 IN. 3 IN. 33 in. . Mineral Wool, between Framing4 A BcD - 0.11 0.13 \ * 0.15 0.17 : 0.19 0.21 0.23 0.25 0.078 0.088 " ` .0.097 0.10 ' 0.11 0.12 0.12 , 0.13 ` 0.27 0.29 0.31 0.33 - 0.14 0.14 0.14 0.15 0.35 , 0.37 0.39 0.41 * 0.43 0.15 . 0.16 0.16 0.16 . . 0.17 0.063 ' 0.054 0.070 ' 0.058 : 0.075 " 0.062 0.080 , 0.066 0.084 0.088 0.091 0.094 . 0.069 0.072 , 0.074 0.076 : ........ . 0'097 0.10 0.10 0.10 - 0.078 0.080 0.081 0.083 : o.ii . . 0.084 0.11 . : , 0.085 0.11 ' 0.086 0.11 - 0.087 0.11 0.088 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 : 33 35 37 ` 39 41 43 45 ; 47 49' 51 53 : 55 : 57 : 59 61 : 63 65 (See text p. 187.) . ' .. '. * This table may be used for determining 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 not applicable to 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, II in. insulating board sheathing studs, gypsum lath and plaster, with 2 in. blanket insulation between studs. According to Table 6, a wall of this construction with no insulation between studs has a coefficient of 0.19 (Wall Noi 4D). . Referring to Column B above, it will be found that a wall of this value with 2 in. blanket insulation between the studs has a coefficient of 0.084 - ' -. * Coefficients corrected for 2 x 4 framing, 16 in. on centers--15 percent of surfaoe area. t e Based on one air space between framing. - - - - - - * No air space. ". Glass Coefficients The U values for glass sheets and hollow glass block, given in Sections A, B and C 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 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 Burface conductance for radiation and convection combined, based on airto-surface 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 tern- 188 CHAPTER 9 1952 Guide . Table 8. Coefficients of Transmission (J7) of Masonbt Walls Coefficients are expressed in Bit* 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 IS mph, . TYPE 07 MASONRY 1 INTERIOR FINISH . (Plus Insulation Waxes Insicatxd) - i I F . bs i 1! a 1 d 1 3 33 41 3 Jl *t k sj 11 si g-S ta 1 i fSi iiiIs 3 a J. li ?i k all IdE ACE nM 8 2 3 & ABc DE FGH 8 0-60 0.46 022 021 020 022 022 026 0.14 67 12 o,,v 024 025 025- 024 0.19 029 024 023 68 16 0.28 027 .021 021 020 027 026 0.13 022 69 8 0.40 027 027 027 026 020 020 025 0.13 70 10 029 027 027 027 026 020 0.19 025 023 71 12 020 028 022 022 021 .0.17 027 023 022 72 16 024 024 029 029 0.18 0.15 0.15 023 021 73 8 0.70 0,04 029 028 026 026 025 028 026 74 13 027 023 025 024 023 024 023 027 026 76 16 049 0.45 021 021 029 022 022 026 024 78 24 027 025 026 026 025 029 029 025 023 77 . 6 0.79 0.71 0.42 0.41 029 027 026 029 0.16 78 8 0.70 0.61 029 028 026 026 025 0.18 026 79 10 0.63 028 027 026 024 025 024 028 0.16 80 12 027 023 025 024 023 024 023 027 025 81 Gravel Aggregate 8 0.56 032 034 034 032 034 033 027 025 82 12 0.49 0.46 032 031 030 032 033 026 024 83 Cinder Aggregate 8 0.41 039 038 038 037 031 030 0.15 023 84 12 038 036 0.36 036 035 030 '0.19 025 023 85 " light Weight Aggregate* . 8 036 034 036 035 034 029 029 0.15 023 88 12 034 0.33 0J ,034 034 0.19 0.18 0.14 023 87 (See text p. 182.) ' Based on 4 in. hard brick and remainder common brick. 6 The 8 in. and 10 in. tOe figures are based on two cells in the direction of heat flow. The 12 in. tile is based on three cells in the direction of heat fl*>w. The 16 in. tile consists of one 10 in. and one 6 in. tile, each having two cells in the direction of heat flow. e Limestone or sandstone. * These figures may be used with sufficient accuracy for concrete walls with stucco exterior finish. * Expanded slag, burned clay or pumice, 1 ' ' S Thickness of plaster assumed i in. s Thickness of plaster assumed } in; . * Based on 2 in. furring strips; one air space. Heat Transmission Coefficients of Building Materials 189JJ (U)Table 9. Coefficients of Transmission of Bbick and Stone Veneer Masonbt Walls Coefficients are expressed in Btu per (hour) (equate foot) (Fahrenheit degree difference in temperature between the air on the two sides), and are based on an outside wind velocity of 15 mph. TYPICAL CONSTRUCTION FACING BACKING. :. INTERIOR FINISH (Plus Insulation Wbbbb Indicated) iI s a s1 & 5 d! a* _d s 3 3 9si i 4' ais, S- 3 a ao I3 |3 1 32 l fl J3 3. JB 3. If 1s 5 l| fl 1 3 A 3 i GQ s| 3 e- ft !? i| II gd 13 la "T 3*9 WP 3S la s5 si 3j 3 8 55 1 s s o\ AS AS A B c D E 'F G H i 6 In. Hollow Tllet 034 035 035 034 029 0.18 024 013 88 8 In. Hollow TUe*__________________ 034 032 035 034 033 029 028 024 023 89 4 In. Brick Veneer* 03S 034 035 035 033 034 033 017 025 90 034 030 033 033 031 033 033 027 025 91 8 In. ConcreteBlocks, 8 lu Concrete bEE 0.44 0.41 039 039 038 031 021 026 014 92 (Cinder Aggregate) ......... 034 033 035 034 034 029 018 014 013 93 8 In. Concrete Blocks* ,^ (light WeightAggregate)*.:____ 031 039 033 033 022 028 027 024 022 94 6 In. HriltnwTibA & in. Hollow Till*........ 037 035 036 036 035 019 029 025 013 9S 036 034 035 035 034 019 029 014 023 96 4ln Cut Veneer* 0.63 038 037 036 034 035 034 028 015 97 037 033 035 034 033 034 033 027 025 98 8 In. Concrete Blocks* (Gravel Aggregate)........... .......... 0.47 0.44 030 030 039 032 031 026 014 99 8 la Concrete Bloefce* - (Cmdex Aggregate)___________ 036 034 035 035 034 029 029 015 023 100 8 In. Concrete Blocks* : (light WeightAggregate)*-_____ 032 030 033 033 032 028 0.17 014 022 101 (See text'p. 182.) ` Calculation based on i in. cement mortar between backing and facing, except in the case of the con- tt'ete backing which is assumed to be poured in place. * The hollow tile figures are based on two air cells in the direction of beat flow. . Hollow concrete blocks. ' . Expanded slag, burned clay or pumice. * Thickness of plaster assumed } in. 1 Thickness of \ in. 8 Based on 2 in. furring strips; one air apace. 190 CHAPTER 9 1952 Guide Table 10. Coefficients of Transmission (17) of Frame Partitions or Interior Walls" Coefficient) are expressed in Bin per (hour) (square foot) (Fahrenheit decree difference in temperature between the air on the two sides), and are based on still atr (no wind) conditions on both sides. INTERIOR .FINISH Studs SINGLE PARTITION (Finish on one side only of studs) DOUBLE PARTITION (Finish on both skies of studs) No nrauumoH BBTWXHN STUDS ln.Bunxsr* BETWKBfl 8TUD8. On azb spacb. Metal Lath and Plaster*^ Gypeum Board (M in.) Decorated.^. Wood Lath and Plaster. Gypeum Lath (M In*) Ra8tered*_ Plywood (H In.) Plain or Decorated.. Insulating Board Lath CM in.) Plastered*.. Insulating Board (l in.) Plastered*-- A` 0.69 0.67 0.62 061 069 036 - 03$ 023 ' ' B 039 0J7 0.34 034 033 0.19 018 012 e 016 016 016 016 016 0J1 Oil 0.08S (See text p. 182.). a Coefficients not weighted; effect of studding neglected. ': . * Plaster assumed 2 in. thick. .. _ e Plaster assumed 1 in. thick. _ d For partitions with other insulations between studs refer to Table 7, using values in Column B of above table, in left-hand column of Table 7. Example: What is the coefficient of transmission ( U) of a rartofaon consisting of gypsum lath and plaster on both sides of studs with 2 in. blanket between studs? Sedunmu According to above table, this partition with no insulation between studs (No. 4B) has a coefficient of 0.34. Beferring to Table 7, 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). (U)11.Table Coefficients of Transmission of Masonry Partitions Coeffiiciente are expressed in Bln per (hour) (square. the atr on the two sides), and are based on - (fik MAKft ' Ia TYPE OF PARTITION 1 11 I Fahrenheit degree difference in temperature between atr (no wind) conditions on both sides. TYPE OF FINISH No Fnasa (Plain walls) PlASTKB Own 8n>a AB FU8RB Both 8mxs C a 1 1 n 8 0^0 0.47 4 045 . . - 0.41 043 040 9 3 O^S 4 0^9 023 . 028 022 027 11 12 Hoilow Tobob . Blocks Cinder Aggregate .... ,..... 3 4 Light Wdght Aggrcgriet------ 3 4 060 046 . 041 035 0.47 0.42 029 034 043 040 037 0.32 13 14 13 16 4 (See text p. 182.) 2 in. solid plaster partition, U =* 0.63. * Expanded slag, burned clay or pumice. OAO 0.46 0.41 17 J------ -- T a b l e 12. C o e f f ic ie n t s o f T r a n s m is s io n (U) o f F r a m e C o n s t r u c t io n .Ce i l i n g s a n d F l o o r s ............. ;. Coefficienta are expressed in B tu per (hour) (square fo o t) (F ahrenheit degree difference between the a ir on the two tides) and are based on s till a ir (no xnnd) conditions on both sides. F o r coefficients w ith in s u la tio n betw een jo is ts , see T ab le. 7. Heat Transmission Coefficients of Building Materials . grataj| |Ji (S^E 5333 s^ssss oooo 3i-3 . 1] 333 RfcSS ooeo oooo e-e oooo oooo ;Is ~*ooo ddoe> sill. ceeoNh oooc . neeg oooo 8S w <ooo oooc oooo 191 .S ^-S -S3- 53 3JA aa9 51 5 sa ft' -^3-i bseg-i go Sa a ox 113 a 2 f dS 8ZS 3 c 3 ss szS in . S Ss j*s^a s.3 ISs 33 ibl oSa eei 111! 3 ,s- 'to .S2-' S3 b 2> "C 13 x2oa3o pSc 511S32 p E ta 8 03 " S. a I3S _ Spb* abo J.-3>^_~ow - S"9 a % f. *f I I i g 3 .8 igl- II' $ <3 a S a S s E sg-S 38 o. os* S e=<: 192 CHAPTER 9 1952 Guide Tabu: 13. Coefficients of Transmission ([/) of Concrete Construction Floors and Ceilings Coefficient* are expressed in Btu per (hour) (square foot) (Fahrenheit degree difference in temperature between the aiit on the two sides), and are based on stiU air (no wind) conditions on both sides. type of emmo TYPE ,OF FLOOBINO Thicknim OP . CoSCBBtP (Inches) No Hooting (Caserete Bare) . T3e*or Temno Flooring an Concrete Directly on Concrete Parquet* Flocnz^ Is Mastin' on Concrete Double Wood Floor cm Seepezs* j AB c D E 8 , 068 065 0.66 045 025 1 6 059 *056 oil 0.41 023 2 10 060 - 0.48 049 026 022 3 3o 3e 3o in* Raster Applied to Underside of 8 6 10 082 054. 040 059 022 044 060 053 045 024 022 021 4 6 6 Metal lath and Plaster* Suspended or Gypsum Board 04 &) and Plaster/-- 8 0 10 8 6 10 0.38 0.85 .032 020 023 080 027 024 021 037 035 032 025 035 022 . . 033 029 030 020 * 028 028 028 027 024 019 018 017 019 018 017 7 8 9 10 11 12 InsojattngBeard loth 04bv)andPlaster/ 8 6 025 ' 023 024 023 025 023 : 021 ' 020 015 015 IS 14 022 021 022 0U9 014 18 Thickness of tile assumed to be 1 in. * Conductivity of asphalt tile assumed to be 3.1. . * Thickness of wood assumed to Be in.; thickness of mastic, l in. (k 4.5). .Col. D may also be used for concrete covered with carpet; ... d Based on if in. yellow pine or fir sub-flooring and H in. hardwood finish flooring with an air space between sub-floor and concrete. ' * Thickness of plaster assumed to be f in. - / Thickness of plaster assumed to be } in. - . - . 9 For other thickness of concrete, interpolate. Table 14. (U)Coefficients of Transmission of Concbete Basement Floors on Ground with Various Types of Finish Flooring U -- 0.10 Btu per (hr) (ea ft) (Fahrenheit degree temperature difference between the ground pnd the air over the floor). . (See text p. 185.) * Since few data are available, a coefficient of 0.10 is frequently used for all types of basement concrete floors on the ground, with or without insulation. For basement wall below grade, use the same average coefficient (0.10). A lower ground temperature should, however, be used for walls than floors as explained in Chapter It. For further data see A.8.H.VJ5. Research Report No. 1213--Heat Loss Through Base* ment Walls and Floors, by F. C. Houghten, S. I. Taimuty, Carl Gutberiet and C, J. Brown (AJS.H.V.E. Transactions, Vol. 48, 1942, p. 369). perature of the room surfaces seen by the glass.. Special consideration should be given to those cases where the glass sees interior surfaces at temperatures differing greatly from the room air temperature, i.e.,. such cases as in sun rooms, greenhouses, and some pane} heated rooms, or where there is an unusual amount of air motion in the vicinity of the glass. Although based on zero outdoor air, the values change only slightly with different design temperatures, being about 5 percent greater for a 30 F outdoor design temperature. In computing the Table 20 values, consideration of the dependence of the indoor surface conductances upon temperature and direction of heat flow leads to surface conductances averaging about 1.50 for block and vertical glass, and about 1.80 for horizontal glass, as compared to the Heat Transmission Coefficients of'Building`Materials 193 15.Table (U)Coefficients 'of Transmission ' of 'Flat Roofs Covered with Built-up Roofing; No Ceiling--Under Side of Roof Exposed ' (See Table 16 for Flat Roofs with Ceilings) Thai coefficient are expressed in Btu par {hour) (square foot) (Fahrenheit decree difference in temperature' between the avron'the two eides), and are based on an outside wind velocity of IS mph. Type op Roop Deck Insulation on Top op Deck (Covered with Built-Up Rooting) Thick ness op Roof Deck . (Inches) No In sula tion '' Insulating Board ' (Thickness' Below) - tin. 1 In. It In. 2 In. CORKBOABD (Thickness Below) 1 In. It In. 2 In. Num ber BEH Flat Metal|Roof DeckJ' tM/OUTIM/ JL 0.94 0.18 0.14 0.17 0.15 Precast Cement Tile ' /iir fcooftNCj /Tut yfimtx/JF* Concrete * ^ injuutiaii UCOMHfij / coHtttre. 1| in. 0.84 0.17 0.16 2 in. 4 in. 6 in. 0.82 0.73 0.65 0.36 0.34 0.33 0.24 0.23 0.22 0.17 0.17 0.16 0.14 0.13 0.13 0.22 0.21 0.31 0.16 0.16 0.15 0.13 0.12 0.12 Gypsum Fiber Concrete6 on t in. Gypsum Board 2RimirMicJUt/ffK ram MAAD ' 't in. 'I in. 0.38 0.31 0.24 0.21 0.18 0.16 0.14 0.13 0.12 0.11 0.17 0.15 0.13 0.12 0.11 0.10 Wood* lOCftlHNf/iUUOIflf/l/ mmrnm w#op7 1 in. It in. 2 in. 3 in., 0.49 0.37 0.32 0.23 0.28 0.24 0.23 0.17 0.20 0.17 0.16 0.14 0.15 0.14 0.13 0.11 0.12 0.11 0.11 0.096 0.19 0.17 0.16 0.13 0.14 0.13 0.12 0.11 0.12 0.11 0.10 0.091 - transmission of bare corrugated iron (no roofing) ia IA0 Btu per (hr) (sq ft of projected Ta) (F deg difference in temperature) based on An outside wind velocity of 15 mph. .. 871 percent gypeum, lit percent wood fiber. Thickness indicated includes t in. gypsum board. * Nominal thicknesses specified--actual. thicknesses used in calculations. . . '. ish ISil Ii: -oi' nv :l -1 194 Table. CHAPTER 9 16. Coefficients of .Transmission ({/) of Flat Roofs Covered with Built-up .Roofing. With Lath and Plaster Ceilings" (See Table 15 for Flat Roofs, with No Ceilings) 1952 Guide n Heat Transmission Coefficients of-Building Materials 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 io n ' (U) o f P it c h e d R o o f s Coefficient* are ezproceed in B tu per (hour) (equate fo o t) (F ahrenheit degree difference i n tem perature between the a ir on the tw o tid e s ), and are bated on a n outeide w in d velocity o f lit m ph, , . ' d Plaster assumed 3 In. thick. * Plaster assumed ) in. thick. 195 196 CHAPTER 9 1952 Guide Table 18. Combined Coefficients of Transmission (17) of Pitched Roofs" and Horizontal Ceilings--Based on Ceiling Area4 Coefficients are expressed in Btu per (hqur) (square foot of ceUing area) {Fahrenheit degree difference in temperature between the air on the two sides), and are based m an outside trind velocity of 16 mph. type or Boorma and boot sheathing cmnva C0EFF1CIENT/ (Fboh TABLEU) Wood Bbtmim oh Wood 8nm< Asphalt SsncGLBPOB Rcu Roctxsu oh Wood Bheithot* . Noioof (Rafters Exposed) (0,- 0A8) Mlnlan* . nans Board : of Rafters (Ur- OB) 1 In. Insu lating Board on Under Side of Baftos (Ur - 016) NoBoqf Insulation (Rafters Exposed) (Ur - 058) Min* Insu lating Board cm Under Side of Rafters (Or - 013) 1 In. Insu lating Board on Under Side of Bifttn We- 017) Z A. B c D. 'E F aio au 052 052 0085 - -- 0078 0092 ^ s- 0578 npoO 0582 051 0587 0566 057 0574 0578 0587 0594 050 Oil 0574 0579 0583 . nrtftx 0567 ' 0571 0576 0579 19 20 21 n 0J4 051 > . 0591 0581 ou ; 0593 0588. 28 056 012 0596 . 0084 012 056 018 050 0587 053 057 053 050 : 0590 058 . 058 014 Oil v 0598 014 059 014 Oil 0095 056 020 on ss on 025 ,, 026 027 028 029 . 015 Oil *' QjQffi 055 052-- 050 056 012 . OlO 056 : 052 050 017 = 018 021 017 oji 1 058 053 018 ' 058 019 014 OJS 014 051 Oil 051 019 058 056 016 017 ; 057 018 018. 059 059 059 ' 020 080 020 014 ais 020 044 021 055 052 022 086 022 016 : 058 022 086 022 055 053 028 087 023 i 016 ; 058 023 045 069 04! 061 067 069 025 . 029 - 059 040 051 041 017 ; 018 058 : 019 v 019 ` 059 : 058 054 016 015 - 056 016 046 050 041 041 048 043 .0097 050 050 051 051 012 052 012 052 012 058 058 058 014 014 054 056 056 056 056 017 019 059 059 040 040 0086 0589. 0592 059$ 0598 24 2a5 2a7 050 050 Oil 051 Oil aa 81 82 a on 84 051 85 OU 89 012 U 052 89 Oil 39 058 40 058 41 058 42 053 48 054 016 056 056 ` 056 016 44 45 41 47 48 49 (See text on p. 184.) - Calculations.baaed on 4 pitch roof (n 15) using the, following formula: ,- ,, Ur X Vet U --------------UZ, Ur-\---- n U = combined coefficient-to be used with ceiling area.'.' . Ur = coefficient of transmission of the roof. Uce 'coefficient of transmission of the ceiling. ' => the ratio of the area of the roof to the area of the ceiling. Use cftfling area (not roof area) with these coefficients. * Coefficients in Columns D, E and F may be used with sufficient accuracy for tile, slate and rigid as bestos shingles on wood sheeting. A Based on 1 x 4 in. strips spaced 2 in. apart. . * Sheathing assumed 3$ in. thick. / Values;of Uce to be used in this column may be selected from Table 12. Heat Transmission Coefficients, of Building Materials 197 Table 19. Coefficients of Transmission (17) oeSolld Wood Doors. .. , , Coefficients are expressediintnbBitiun Ppef7r" (hour) [ignorefoot) (Fahrenheit degree difference in temperature between' ' the air on tAet`xfo' s' ides), and are based upon an outside wind velocity of 16 ppA. ` . Nominal Thickness ' -Inches , Actual Thickness ' Inches - U8.* .. .. , , , u.$ 'Exposed Dooa WithGlass Stobm Do'ok* -. - 1 u H ft M* 1A .11 0.69 ,0.59 0.52 0.51 ' . 0.35 0.32 0.30 0.30 r: 2 li 2* 2* 3- 2| 0.46 0.38 : , 0.33 - 0.28 0.25 > ,0.23 ` . , wiuvuum using s = ior wooq;/< / = 0.0 and 150 for air space. . _ - s ,A V 'npntct 055 may be used for single exposed doors containing thin wood panels or single panes of glass, and 059 for the same with gi*** storm doom .. . " 8 50 percent glass and thin wood .* . . '':' -- Table 20. Coefficients of Transmission (/) of Windows, Skylights and Glass Block Walls Coefficient^ are expreeccd in Btu per (hour) (eguare foot) (Fahrenheit degree difference in temperature between the asr on the two sides), and are based upon the following outdoor conditions: 0 F air temperature, ____________________________________ dear skies, no solar radiation - - Section A--Vbbtical Glass Sheets Numbbb op 8hbzts Ohs Two . .. . : THEBE . . Air Spaoe, inches.............................. None U............................... 1.13 H 0.61 H 0.66 1* - 0.63 . H 0.41 H 0.80 1* 0.84 Section B--Hobixontal Glass Shuts (abat tlow dp) . Numbbb op Sheets : . ONE.: . : . Two Air Spaoe, inches....................... U...................... None 1.40 H 0*7 0.66 1 . 0.63 ' SacTiojr C--Walls or Hollow Glass Block DsscmnioH 54}xx 51 x 31 in. thick., f x 7} x 3{ in. thick Viix 7] x 3t in. tthhiiick with glass fiber screen dividing ^ cavity.. 0.60 0.56 0.48 Section D--Approximate Application Factobs fob Windows Multiply Flat Glass U Values bt TLlesb Factobs Siifgle Glass Double Glass6 Windows with Percent^ Glass |pSE2f' : 1 pSf Factor Sheets.................... Metal RmI) ' 100 l.'00! ' 1 106 1.00 1 . : 80 0.90 1 80 0.95 i 80 o'oo 60 0.80 1 60 .0.85 I . 60 0.80 80 1.00 I 80 140 | 80 - 1.00* (See text p.187.) ' ' '. ' * For 1 in. or greater. ' , '' ' '' Unit type double glasing (two lights or panes in same opening). ' ' * with U. values for two sheets with 1 in. air apaoe. ' -. . ... ., Baaed on area of exposed portion of sash; does not include frame or portions of sash by frame. For.metal storm sash or metal sash with attached storm pan - / - 198 , CHAPTER 9 i- - 1952 Guide '' ' : 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 testa summarized in a research bulletin16, and are approximate only. In practice,, some variation in heat flow through windows having . the same ratio of glass to sash area, may be expected because of difference in construction details and in air space edge effects. ' " CALCULATING SURFACE TEMPERATURES In many heating and cooling load calculations it is necessary to deter 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: ' Ri . (t O R, ~ (ii -.) (6) where " ". ' ' ' :,r . \. .' . '' ' Ri <= the reBistance from the inside air to any point in the structure at which the .............. temperature is to be determined. ................... lit = the overall resistance of the wall from inside air to outside air. fi = inside air temperature. ... ix = temperature to be determined. - t, = outside air temperature. "' 1 ................... - ' Example 2: 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: J R, = 1/fi = 1/1.65 = 0.606 . R, = 1/17 = 1/0.25 - 4.00 . Then, by. Equation 6 - ~ ;---- . 0,606 70 -- tx . 4.00 = 70 -- (-20) : .. ' ' "' A = 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 23, Panel Heating. . WATER VAPOR AND CONDENSATION IN CONSTRUCTION Water as a vapor is present in all air and as adsorbed moisture in build ing materials such as wood. Even dense materials like glass hold consider able adsorbed moisture on their surfaces. In each of these places water may be harmless or even desirable, if its quantity is not excessive. Ex cessive moisture in building materials may cause mould, rot, and rust. Water blistering may damage seriously the exterior paint on wood siding when the siding moisture content rises above a safe level. While excessive Heat Transmission Coefficients of Building Materials 199 moisture in building materials may be caused'by rain leakage, 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 ih winter, and in the enclosure of refrigerated spaces at all seasons. Water vapor released within a budding, either incidentally or intentionally, may result ih 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 arid 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 demand1 a high humidity; require buildings designed to reduces the effect of moisture oh the structure. Moisture problems in residences occur in winter and become 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.16 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. ; 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 arid 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 arid.the heat transfer coefficient [/of the surface structure. Based on a value of 1.65 for the inside surface, conductance, Fig. 6 shows the relative humidity in a room at 70 F. when visible condensation will appear at various [/-values. The curves for. single and double glass at their usual [/-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 low er 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 an- spaces. Since con densation seeks the coldest spot, values from Fig. 6 can be applied only with caution. As a result, the limit of relative humidity for a non-homogeneous wall is lower than might be inferred from its average [/-value. The avoidance of interior visible condensation is partly a construction 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 in winter, F l| ! I ;2i II j! 3: }.| i -i L; 1 r 1' :j 'C} I * !}' i iftfi i !i i 2-00' ; v CHAPTER 9 ..1.952 Guide 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 visible surfaces. Vapor permeates through certain materials very readily and may penetrate exterior or cold walls and contact material therein having a 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 ,. Fig. 6. Relative Humiditt at Which Visible Condensation Will Appeab on Inside Stxhpace 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 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 as 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). The term permeability has frequently been applied to the rate of vapor transmission for the thickness of the material considered or tested, but 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 gested17 that the term permeance (similar to conductance in heat transfer) ' Heat Transmission Coefficients of Building Materials 201 be. used .whep referring to, any. specimen of definite' thickness, or an as sembly of, such pieces. This recommendation is followed in this chapter. The -term; permeability, as used herein, defines a property of, the, material and is numerically equal to the permeance of. a unit thickness. ,. The theory covering water vapor transmission through materials leads to the following formula, . . W = MAT Ap . (7) where, W = .total weight 'of vapor transmitted through, the specimen, grains. . A =. area of the specimen, square feet. . ......... . . . .... /; . T = time during which the.transmission occurred, hours. . , 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) (hour) (inch of mercury vapor pressure difference). . The basic units in Equation 7 are favored by the building industry. The designation perm for the unit of permeance'has been proposed17 as a convenient substitute for the unit,T grain per (squaje foot) (hour) (inch of mercury vapor pressure difference), and this recommendation is followed herein. :. j The weight ofvapor 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: ; where, )' '' ' or, n = Mt '' ;' ' . '' , '. (8) '- M = the permeance of the specimen, perms. : t the thickness of the'specimen, inches. ' - ' . , . .: . Evidently ti is the permeance of a unit thickness of the material, which is its permeability,' as above defined. 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 7'and 8may be combined to give: V : ; ... w = (9) 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 202 CHAPTER 9 1952`Gvude series is the sum of the resistances of its component parts provided con densation does hot take place within' the assembly. Expressed in the more usual terms, the'permeances (Mi, Mi, M3, etc.) of the individual pieces may be combined by use of the'formula'" - , M = _--L---,--_--L---,---i----+---.--.--.--2--_ do) Equation 10 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, the conditions of moisture movement through a building wall are generally PERCENT RELATIVE HUM0ITY ON THE HIGH PRESSURE SIDE Fio. 7. Permeability of Wood (Sugar Pine) different. A steady state, where the entering and leaving moisture are equal, rarely exists, and frequently, the moisture in some portion of the path is liquid, in which case forces of capillarity and gravity are usually 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 permeable to water vapor when, the relative humidity is high. Since the equilibrium moisture content of permeable materials is increased to a greater or less degree by exposure to high relative humidity, it is likely that this sorbed moisture contributes to the mechanism of transfer. The variations in the permeability of sugar pine wood are shown in ' Fig. 7.18 It isnotable that high relative humidity on either side of a speci men increases its permeance and the average permeability of the piece. Heat Transmission Coefficients of Building Materials 203 The spot permeability is shown, but-the average, is more readily, used in practical calculation. Temperature also affects permeability,; but for.most materials is considered a minor factor, although data are .few, ;These variations are to be expected in most materials and therefore, due care is required in choosing for each the proper value at its exposure conditions. Exact calculation by any of the preceding formulas, therefore, requires, a knowledge of such variations as shown in Fig. 7 for each material, but approximate calculations are readily made and are adequate for most requirements. Permeance Data and Testing The simplest method of finding the vapor permeance of a specimen is to seal it over the top of a cup containing desiccant, or water, placing it in a Table 21. Conversion Factors for Vapor Transfer Units Multiply Number of ' WVT Units . .. to Obtain J, . grams . ' (24 hrs) (sq m) grains (hr) (sq ft) . , grams (34 hre) (eq m) by same method* - '. grains (hr) (sq ft) Perms by same method* by same method* ` method A A B, 73.4 F method C A D, 90 F method E, 100 - F .. 1 0.0597 0.144 0.0840 0.0344 16.7 1 ' ' 2.41 1.41 0.575 . % Relative Humidity on the Two Sides op-Specimen: ;; Method ' Temperature>F In cup Outside cup A. B C: D . 73.4 73.4 90 90 100 . 0 100 0 100 . 0 , ' ; 50 50 50 . -. 50 90 . .' '. * Data obtained by one method cannot be reliably converted to another method; controlled atmosphere, and weighing it periodically. The steady rate, of weight gain or loss is normally the water Vapor transfer; When the'cup contains a desiccant the procedure is called the dry-cup method and when the cup contains water, the wet-cup method. Usually the 'outside at? mosphere is heid 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. 1 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 204 CHAPTER 9 1952 Guide per- (unit area) (unit time). Such, data may be called water vapor traps- - 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 ban be converted to permeance, care being taken if conversion of'the basic units (weight, area-and time) is also required. -The following formula applies: / : WVT rating Permeance = ----------- Ap (11) where, , WVT 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 21 presents tlie conversion factors applicable to the commonly used units and test methods. ' Table 22 presents some data on typical building materials showing in each case the source and method and, where applicable, the thickness tested. .: . Water-proofed building papers are listed in Federal Specifications UU-P147, May 24, 1948, according to water vapor resistance required as: Class A. For uses where a high degree of water vapor resistance is required. Class B. For uses where a lower degree of water vapor resistance ana of water resistance is required. _ __ _ Class C. For uses where a moderate degree of water resistance is required. Class D. For uses where low resistance to water vapor is required. . . It may be noted that a paper may be tvoter-proof i.e. possess water re sistance, and still have low water vapor resistance. Detail requirements in these specifications are given as follows, the specified WVT Test being a dry method at 73F: 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 inyitation for bids. Paper of both strengths shalf have a minimum water resistance of 24 hr; and a maxi mum water vapor permeability (WVT) of 4 grams per square meter per 24 hr, (i.e. 0.676 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 shall 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). . .; : 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 to escape. The resulting balance may be expressed in terms of relative humidity if the inside temperature is 70 F. The relative humidity in heated buildings Heat Transmission Coefficients of Building Materials 205 Table 22. Permeance and Permeability op Materials ' ` to Water Vapor '_ ' Per meance . Perm Permea bility* Perm-inch RHpflHt Aib (still) .' ` '' ' Insulation : ' Cellular glim* - , -. . . Corkboard `- Corkboard . ... ' Structural Insulating Board (vegetable, uncoated) Mineral Wool (unprotected) . ' .. Wood . . Sugar Pine (see Fig. 7) . .; Plywood (Exterior type 3 ply D.F.), \i in. Plywood (Interior type 3 ply D.F.)* H in. Masonrt . ` ... Concrete (1:2:4 Mix) . .. ' Concrete (8* cored block wall,' limestone agrgt.) Brick wall--with mortar-r4 in. . . . . Tile wall--with mortar--4 in. Interior Finish . Plaster on wood lath '. ................. Plaster on metal lath--H* . Plaster on plain gypsum lath (with studs) Gypsum wall board--plain--H in. Insulating wall board (uncoated)--H in. . Paint--2 coats Asphaltic paint on plywood ' Aluminum in varnish on wood Enamels, brushed on smooth plaster Primers or Sealers on insulating wall board . Various Primers + 1 coat flat paint on plaster Flat paint (alone) on insulating wall beard Water Emulsions on insulating wall board Paint--Exterior, 3 coats ^ White lead <fc oil prepared paint on wood siding White lead-sine oxide A linseed oil on wood 0.72 . 1.86 2.4 0.8 . 0.12 11. .15. 20 50. 50-90 0.4, 0.3t0.5 0.6-1.6 0.9-2.1 1.6-3. 4. 30.-85. 0.3-1.0 0.9 120. o;o' 2.1-29..66 12106-.6: 0.. 02-73 75-0 .100-46 40-x 100-30 b 0.4-6.4 various. 60- i 60-. - tv 44 100-45 79-68 50-x 60-x 100-30 40-x 40-86 60-20 40-x 100-30 95-0 ' 62r0 40vx 40-x 40-x 40-x 60-0 96-0 Rep4 18 21 24 : 22 19' 18 26' 26 24 18 19 22 18 2228 19 26 18 22 22 22 22 per 500 sq ft Permeance-Perms dry cup wet cup * Building Papers and Felts Duplex sheet, asphalt laminae, aluminum foil one side Saturated and eooterf felt heavy roll roofing - Kraft and asphalt laminae. Reinforced 30-120-30 Insulation back up, asphait-sat., one side glossy - Asphalt-saturated and coated sheathing paper . Asphalt-saturated sheathing paper . 15-pound asphalt felt *: ' 16-pound tar felt . .* . Single sheet Kraft, double infused' ` 43 326 34 . 21 43 . 22 70 70 16 0.002 0.05 . 0.3 0.4 0.3 . 3.3 1.0 4.0 30.8 0.176 27 0.24 : 1.8 0.6-4.2 . 0.6 .. 20.2 ' 5.6' 18.2 41:9 27 27 27 .27 27 ;'27 27 27 Description is a guide only, and does not insure, permeance.. - - . . (( .t Methods: d--dry cup; w--wet cup; t--two temperatures; b--special cell; v--air velocity both sides; 4--average of four methods. ` , - ' . < ' - t References. No. 22 also indudes Bulletins 22 and 25 of the Engineering Experiment Station, University of Minnesota. No. 28 includes data to be published by the Engineering Experiment Station, The Pennsylvania State College. ` ., .... . - 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 constructed small' houses although the average house relative humidity is probably below 25 percent. Surveys in residences show that the relative humidity increases 206 ! C^ HAPTER 9 1952 Guide as would be expected in warmer weather.; Fig. 8 represents the results of one such survey.13 ' 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 fibrous 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 side may occur harmlessly in masonry walls when the weather is above freezing but water seepage into the building must obviously be avoided. In typical frame construction with wood sheathing which has large water absorbing capacity, seepage is rare and occurs only after a long period of steady cold weather. More generally, moisture accumulates in wood sheathing and siding through the colder months and reaches a peak in late Heat Transmission Coefficients of Building Materials 207 wall structure permits. Ventilation, as discussed later in this chapter, is an important correction factor in these cases. Insulation in a wall or roof reduces-heat loss and lowers the temperature of the outer elements of the1 structure, thus increasing the possibility of condensation if the vapor path to the cold surface is not blocked. Since low vapor resistance is a characteristic of fibrous insulation, the needed vapor resistance must be provided by other means. It is to be noted that, in typical residential conditions, condensation does not occur in fibrous insulationdtself, except when frost has formed on sheathing arid gradually Fig. 8. Relative Humidity in Dwellings winter, after which the drying of spring and summer completes the annual cycle. The average winter temperature arid its duration are factors in the condensation problem. In Fig. 9 the United States is divided into three condensation zones based on winter weather conditions.2" 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 warmer. Within' each zone, similar degrees of con densation trouble are to be expected, and similar corrective measures apply. . .. In roofs, the condensation problem is much the same as in walls. The roof covering may be even more resistant to the escape of vapor than wall coverings such as paint;.and while paint is likely to be ruptured by exces sive moisture, no such relief occurs in roofs. Thus roofs furnish con 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 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 (Zones Include Arens with Design Temperatures nbout as follows Zone I. -20 F and lower .. Zone II, 0 F to -- 20 F; and Zone III, above OF) ' 1' built backward among the fibers. Wet insulation may result from this condition or from liquid condensation seeping down from, a higher level. Control of Concealed Condensation - ': An excessive accumulation of moisture in walls (or roofs) can be prer vented by one or more of the following measures: (1) 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 amont of cavity ventilation is essential in cases where the vapor inflow is not completely stopped and the moisture storing capacity of the outer wall demerits' is slight. -This applies to some prefabricated designs using metal siding. 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. 208 CHAPTER 9 .1952 Guide 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 also1 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 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 having cavities in ceilings which open into the outside walls. Such cavities allow vapor entering.Jhe ceiling to diffuse or be transported to the cold areas. Stoppage of this path is difficult, requiring normally the painting of the ceiling as well as the walls. Similar treatment niay be required on internal partitions, or at least the first stud space adjacent to the cold wall. The pecessary barrier resistance depends on a number of factors. When the vapior flow, occurs in annual cycles as in heated buildings, the require ment 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-theoutsidewith-materialshighly-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 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. . For 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. ' " '. ' 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 modern dwelling include a vapor barrier when the con struction includes any material-that would be damaged by moisture or its freezing. This applies to all condensation zones when the U value for the wall is lower than 0.25 Bto per (sq ft) (hr) (F deg), arid it applies in 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 be placed as near to the warm surface of the wall as practicable. Second, it Heat Transmission Coefficients of Building Materials 209 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,different 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 over some solid framing member, and not between the studs or in similar places. Usually a two-inch Tap 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 of insulation, should form a continuous unbroken membrane over the entire insulated area. Edges should be lapped'over framing members; ends of strips should be fastened by lapping over plates or headers. All openings Fig. 10. Water Vapor Balance in a Dwelling (Vapor Barrier, 1 perm; Wall and Ceiling Area 2000 sqft Insulated) 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 meiasure is obviously necessary as an accompaniment to a vapor barrier since, if the barrier blocks entrance into the walls, the water vapor must be removed by other means. No great volume of air change is necessary, however, and normal infiltration alone is frequently all that is required in winter weather. The effectiveness of ventilation is shown in Fig. 10, 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 shown in Fig. 6. By reference to Chapter 6, 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 10, it appears that usual infiltration will normally supply the necessary air change, but that supplementary ventilation may be necessary in kitchen 210 , CHAPTER 9 1952 Guide and laundry for proper vapor control and for the reduction 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 - used.; The vents must be shielded from the entrance of rain and insects. Attics and crawl speces may be considered as parts of the structure, and for these portions ventilation is practically a necessity. Attic ventilation has long been an established practice, but its effectiveness is likely to be diminished by the newer practice of adding insulation to ceilings. In sulation requires added ventilation which in turn necessitates adequate insulation. The recommended ventilation shown in Table 23.for dwellings20 is based on such insulation. The net area refers to the total of all openings free from obstructions. The use of louvers and 8-mesh screen (usually recommended) requires a gross area 2.25 times that listed. In zone I, a ceiling vapor barrier is recommended for all constructions. It is also neces sary 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 de sirable 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 comer, as high as possible, should be provided.20 Their total net area may be calculated by the formula: - ?L 100 + 300 (12) where: L' = the perimeter of the crawl space, linear ft. A -- the area of the crawl space, square feet. * a = the total net area of all vents, (or the gross area if a 4-mesh screen is used), square feet. .. This ventilation is usually sufficient but cools the first floor so much that insulation is needed. A better treatment is a cover on the damp ground.. 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 12. . ., 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 bamer 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 Heat Transmission Coefficients of Building Materials 211 Table 23. Recommended Good Practicem-Lopt and Attic Ventilation Flat Root--Slops Less than 3 Inches in 12 Inches Condensation Zone I: Total net area of. ventilation should be ^ooth^ distributed uniformly at the eaves pit** 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 Roof--Slope oveb 3 Inches in. 12 Inches Condensation Zone I: Total net area of at least 2 louvers on opposite sides located near the ridge to be Hoothb plus a vapor bamer in the top story ceiling. . -' . Condensation Zone II: Same ventilation as for Zone I. A vapor barrier is not considered necessary.' Condensation Zone III: Same as for Zone II. - Hip Roof Condensation Zone I: Total net area of ventilation should be Hoothb with.J6oothb distributed uniformly at' the eaves and $$ooth located at the ridge with all spaces interconnected. A vapor barrier should used in the top story ceiling. . be Condensation Zone II: Same ventilation as for Zone I. A vapor barrier is not considered necessary. Condensation Zone IH: Same as for Zone II. Gable ob Hip Roof--With Occupancy Contemplated Condensation Zone I: Total net area of ventilation shoud be $4oothb with Joothb distributed uniformly at the raves and 6oothD located at the ridge with all spaces interconnected. A vapor barrier should .1o be used on the warm side of the top full story ceiling, the dwarf walls, the sloping part of the roof, and the attic story ceiling. ' Condensation Zone II: Same as for Zone I. ' .- Condensation Zone IH: Same as for Zone I except that a vapor barrier is not considered necessary if insula tion is omitted. .. . , * It is recognised that in many areas increased ventilation may be desirable for summer comfort. For winter comfort, insulation is reoommended between a living space and a loft or attic ventilated at these rates. b Refers to area enclosed within building lines at rave level. - 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. . REFERENCES 1 Standard Method of Test for Thermal Conductivity by Means of the Guarded Hot Pis e, sponsored by 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.VJE. and A.8.T.M. in 1942 (A.S.T.M. designation C-177-42T, Approved 1945). * Heat Transmission Through Building Materials, by F. B. Rowley and A. B. AJgren (University of Min nesota, Engineering Experiment Station Bulletin No. 8, p. 11). . * Thermal Properties of Soils, by Miles S. Keisten (Unnersiiy of Minnesota, Engineering Experiment Sta tion Bulletin No. 21, June 1949). 4 Radiation and Convection from Surfaces in Various Positions, by G. B. Wilkes and C. M. F. Peterson (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 513). . * Radiation Corrections for Basic Constants Used in the Design of All Types of Hearing Systems, by B. F. Raber and F. W. Hutchinson (A.S.H.V.E. Tbansactionb, Vol. 51, 1945, p. 213). A.S.H.V.E. Research Report No. 869--Surface Conductances as Affected by Air Velocity, Temper ature and Character of Surface, by F. B. Rowley, A. B. Algren and J. L. Blackshaw (A.S:H.V.E. Trans actions, Vol: 36, 1930, p. 444). . .. .. 7 Forced Convection Heat Transfer from Flat Surfaces, by G. V. Parmelee and R. G. Hueb8cher (A.S.H.V.E. Research Bulletin No. 3, p. 40; also published in AB.H.V.E. Transactions. Vol. 53. 1947, p. 276). * A.S.H.V.E. Research Report--Heat Flow through Unshaded Glass: Design Data for Calculations, by G. V. Parmelee and W. W. Aubele (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning. June 1950, p. 130). Radiation and Convection Across Air Spaces in Frame Construction, by G. B. Wilkes and C. M. F. Peterson (A.S.H.V.E. Tbansactionb, Vol. 43, 1937, p. 351). . " 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, 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). . . u A.S.H.V.E. Research Report No. 1213--Heat Loss Through Basement Walls and Floors, by F. C. Houghten, S. I. Taimuty, Carl Gutberiet and C. J. Brown (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 369). " Measurements of Heat Losses from Slab Floors, by R. S. Dill, Wm. C. Robinson and H. E. Robinson (National Bureau of Standards, Building Materials and Structures Report BMS 103). 212. CHAPTER 9 1952 Guide M See pp. 130-132 of Reference 7. - . ; ;- Heat Transmission through Glass, by G. V. Parmelee (A.S.H.V.E. Research Bulletin No. 1, July 1947). .. Research in Home Humidity Control, by S. C. Hite and J. L. Dray (Purdue University, Engineering Experiment Station, Research series No. 106, November 1948). n Permeance Measurement Improved by Special Cell, by F. A. Joy and E. R. Queer-{A.S.H.V.E. Jour nal Section, Heating, Piping and Air Conditioning, June 1949, p. 103). - ' . . & Water Vapor Transfer Through Building Materials, by F. A. Joy, E. R. Queer and R. E. Schreiner (Penn" sylvania State College, Engineering Experiment Station Bulletin No. 61, December 1948). . , 11 Remedial Measures for Building Construction, by L. Y. Teesdale (Report R1710 of U. S. Forest Products ^Laboratory 1947). 20 Condensation Control in Dwelling Constructions ( U. S. Housing and Home Finance-Agency, 1949). . u The Diffusion of Water Vapor Through Various Building Materials, by J. D. Babbitt (Canadian Jour nal of Research, Vol. 17, February, 1939, p. 1$). _ n 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 Bulletin No. 17). s The Relation of Wall Construction to Moisture Accumulation in FULType Insulation by Henry J. Barre Iowa State College of Agriculture 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 1941, p. 103). ' Permeability of Paint Films to Moisture by R. I. Wray and A..R. Van Vorst (Industrial and Engineer ing Chemistry Vol. 25, p. 842, 1935). . . . ** 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 1950). v 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. Journal Section Heating, Piping and Air Conditioning, December 1950). BIBLIOGRAPHY A.S.H.VJ3. Research Reports: ;. No. - 852--Effects of Air Velocities on Surface Coefficients, by F. B. Rowley, A. B. Algren and J. L. Black ' ahaw (A.8.H.VJB. Transactions, Vol. 38, 1930, p. 123). .. w0 gQ5--Wind Velocity Gradients Near a Surface and Their Effect on Film Conductance, by F. C* Boughten 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. S3). No 915--Conductivity of Concrete, by F. C. Houghten and Carl Gutberlet (A.S.H.V.E. Transactions, i' VoL 33, 1932, p. 47). - .. No. 964--The Heat Conductivity of Wood at Climatic Temperature Differences, by F. B. ' Rowley (A.8.H.V.E. Transactions, Vol. 39, 1933, p. 329). ' No 996--InqMifctrng Value of Bright Metallic Surfaces, by F. B. Rowley (A.8.H.V.E. Transactions, ; * Vol. 40. 1934, p. 413). . .. No. 1026--Thermal Properties of Concrete Construction, by F. B. Rowley, A. B. Algren and 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). ASH V.E. Research Report--Overall Coefficients for Flat Gloss Determined under Natural Weather Conditions, by G. V. Parmelee and W. W. Aubele (A.S.H.V.E. Journal Section. Heating, Piping and Air Conditioning, December 1948, p. 111). Tnmiiftiing 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. MacLean (A.8.H.V.E. Transactions, Vol. 47, 1941, p. 323). The Specific Heat of Thermal Insulating Materials, by G.B. Wilkes and C.O.Wood (A.6.H.V.E. Trans actions, Vbl. 48, 1942, p. 493). '- .' ' ' Heat Loss Studies in Four Identical Buildings to Determine the Effect of Insulation, by D. B. Andeison (A.S.H.VJ2. Transactions, Vol. 48,1942, p. 471). .' Effect of Ceiling Insulation upon Summer Comfort, by T. D. Phillips (National Bureau of Standards, Report BMS52, July 1, 1940). . Thermal Insulation Made of Wood-Base Materials, Its Application and Use in Houses, by L. V. Teesdale (U. S. Forest Products Laboratory Report No. R1740, October 1949). ` Heat Transmission Through Building Materials, by F. B. Rowley and A. B. Algren (University of Min nesota, Engineering Experiment Station Bulletin No. 8). Building Insulation, by P. D. Close (American Technical Society, Chicago, 1945). . Moisture Condensation in Building Walls, by H. W. Wooley (National Bureau ofStandards, Report BMS63, December 14, 1940). '* Condensation of Moisture and Its Relation to Building Construction and Operation, by F. B. Rowley, A. B. Algren and C. E. Lund (A.8.H.V.E. Transactions, Vol. 45, 1939, p. 231). . ' a Theory Covering the Transfer of Vapor Through Materials, by F. B; Rowley (A.S.H.V.E. Transac tions, Vol. 45, 1939, p. 545). Simultaneous Heat and Vapor Transfer Characteristics of an Insulating Material, by F. G. Hechler, E. R. McLaughlin and E. R. Queer (A.S.H.VJS. Transactions, Vol. 48, 1942, p. 605). Comparative Resistance to Vapor Transmission of Various Building' Materials, by L. V. Tees dale (A.7h.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, Heating, Piping and Air Conditioning, December, 1939, p. 766). Condensation Within Walls, by F: B. Rowley, A. B. Algren and C. E. Lund (A.S.H.V.E. Transactions, Vol. 44, 1938, p. 95). CHAPTER 10 INFILTRATION AND VENTILATION Causes of Infiltration, Infiltration Due to Wind Pressure, Infiltration Hue to Temperature Difference, Sealing of Vertical Openings, 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 . .. THE air leakage which takes place through various apertures in buildings must be considered in heating and cooling calculations, and properly evaluated. This infiltration, as it is'sometimes designated, takes place through cracks around doors and windows, through solid walls, and through fireplaces and chimneys. Although the latter sources of leakage may be considerable, they are often neglected on the assumption that dampers would be closed during periods of extreme cold weather, or that the fire place will be in use at such times, and will therefore contribute to the heat supplied and lessen the heating load. ' .. CAUSES OF INFILTRATION The displacement of heated air in buildings by unheated outside air is due to two causes, namely, (1) the pressure exerted by the wind, and (2) the difference in density of outside and inside air because of differences in temperature. The former is generally referred to as infiltration and the latter as stack or chimney effect. In either case an exact estimate of the amount of infiltration under design conditions is 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 wind velocity and direction; (3) the exposure of the building with respect to air leakage openings, and with respect to adjoining buildings; (4) the variations in outside 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 plaimed 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 side 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 side. 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 that actual building leakages, owing to this building up of pressure, will be 80 per cent of laboratory test values. While there are cases where this is not true, tests in actual buildings substantiate the factor for-the gen 213 214 CHAPTER 10 1952 Guide eral case. Mechanical ventilating systems are frequently designed to 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 tive means, exceeds the infiltration rate, it is common practice to use the greater value in determining the heating capacity to warm the outside air. Infiltration Through Walls Data on infiltration through brick and frame walls are given in Table l.1 The brick walls listed in this table are walls which show poor workman ship, and which are constructed of porous brick and lime mortar. For good workmanship, the leakage through hard brick walls with cementlime mortar does not exceed one-third the values given. These tests indicate that plastering reduces the leakage by about 96 percent ; a heavy . Table 1. Infiltration Through Walls* Expressed in cubic feet per square foot per hour Type op Wall Wind Velocity, Miles per Hour 5 10 15 20 25 30 8yi in. Brick Wallb_ J Plain------------ 2 } Plastered'___ 0.02 4 .8 12 19 23 0.04 0.07 0.11 0.16 0.24 . fPlain________ 13 in. Brick Wallb. < Plastered'___ (.Plastered11___ 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 0.26 * 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. b Constructed of porous brick and lime mortar--workmanship poor. '. .Two.coats prepared gypsum plaster on brick. ' d Furring, lath, and two ooats prepared gypsum plaster on brick. Wall construction: Bevel siding painted or cedar shingles, sheathing, building paper, wood lath and three coats gypsum plaster. . 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 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 Infiltration and Ventilation 215 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 Fig 1. Infiltration Through Various Ttpes of Shingle Construction and length of crack are also considered when the crack method is employed. The amount of infiltration for various types of windows is given in Table 2.* The fit of double-hung wood windows , is determined by crack and clearance. Crack thickness is equivalent to one-half the difference be tween the inside window frame dimension and the outside sash width. The difference between the width of the window frame guide and the sash thickness is considered as the clearance. The length of the perimeter opening or 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 length, plus the meeting rail length. All of the window crack in any given room is not necessarily used in estimating the infiltration heat loss by the crack method. The length of crack to be selected in any given case de pends on the number of exposed sides, as explained in Chapter 11. 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 216 CHAPTER 10 1952 Guide Table 2. Infiltration Through Windows . Expressed in Cubic Feel per Foot of Crack per Hour Remarks Wind Velocity, Miles per Hour 5 10 15 20 25 30 Double-Hung Wood Sash Windows (Un locked) Around frame in masonry wall--not calkedb..:... 3 Around frame in masonry wall--calked.....-- 1 Around frame in wood frame construction*............ 2 Total for average window, non-weatber-etripped,' A-in. crack and A:in. clearance-0 includes wood frame leakage".......................... ?..................... ' 7 ; 4 Total for poorly fitted window, non-weather- stripped, sVn. crack and .sV-in. clearance.0 Includes wood frame leakage*1.................................... 27 Ditto, weatheretripped..................................................... 6 8 2 6 21 13 69 19 Windows* Non-weatberstripped, locked.......................................... 20 Non-weatberstripped, unlocked-- ............... 20 Weatherstripped, unlocked............................................... 6 45 47 19 Saab Windows k Industrial pivoted, A-io. crack*--............................ Architectural projected, A-in. crack" .................. Architectural projected, A-in. crack"....................... Heaw casement section, projected, A-Jd- erackj:. Heavy casement section, projected, A~>n- crack1.. 52 15 20 6 14 3 8 108 36 52 18 32 10 24 14 20 27 36 3 4 A 5 \6.. 11 17. 23 30 39 59 W 104 24 36 .49 63 til 154' 199 249 34 51 71 92 70 96 125 154 74 104 137 170 32 46 60 76 176 244 62* 88 88 116 33 47 52 76 18 26 38 54 304 .372 112 139 152 182 60 74 100 128 36 48 72 92 ' Hollow Metal, vertically pivoted window*.............................. .. .......... 30 88 145 186 221 242 ' * The Values oven in this table, with the exception of those for double-hung and hollow metkl windows - are 20 percent lees than test values to allow for building up of pressure in rooms, and are based od test data, reported in the papers listed in chapter footnotes. . - t- '' ' _. ' b The values given for frame leakage are per foot of sash perimeter, as determined for double-hung wood windoWB. Some of the frame leakage in masonry walls originates'in the brick wall itself, and cannot be pre vented by ^tiring For the additional reason that calking is not done perfectly and deterioratesVith time, - it is cor,id*red advisablw to choose the masonry frame leakage values for calked frames as the average deter mined by the calked and non-calked tests. ' .. > ` . ' . t o The fit of the average double-hung wood window was determined as A;in. crack and A-in. clearance by .measurements on approximately 600 windows under heating season conditions. 'j , d The values given are the totals for the window opening per'foot of sash perimeter, and include frame 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. ; ',r. a A-in. crack and clearance represent a poorly fitted window, much.poorer than average. . - - " f windows tested in place in building, so that no reduction from test values is necessary,'as'mentioned in footnote a. ' - ' . * Industrial! pivoted window generally^ used in industrial buildings. Ventilators horizontally pivoted at center <fr slightly above, lower part swinging put. ' b 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-monumental buildings such as schools. Ventilators swing in or out and are balanced on side arms. &-in. crack is obtainable in the beet practice of manufacture and installation, Vio. crack considered to represent average practioe. i of imatwa design and section shapes as so-called heavy section easement, but of lighter weight. A-in. crack is obtainable in tbe bat practice of manufacture and installation,. A-ia. crack considered to represent average practice. < 1 Mnd of heavy sections. . Ventilators swing in or out and stay set at any degree of opening. . A-in. crack is obtainable in the best practioe of manufacture and installation, A-in. crack consideredto represent average practice. ' '' . ' k with reasonable care in installation, leakage at contacts where windows are attached to steel frame-` wn-k and at muiliona, is negligible. With A-in. crack, representing poor installation, leakage at contact with steel framework is about one third, and at muiliona, about one-sixth of that given for industrial pivoted windows in the table. 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 Infiltration and Ventilation 217 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 Table 3. Infiltration Through 72-Inch Revolving Door and 36-Inch Swinging DooR*.b , (Cubic Feet per Person per Passage) - ' Usage Freelt-Rbvolvtnq Door Door Equipped with Brake Infrequent ' 75 ' 60 . 40 : '' 60 50 40 39-Inch Swinging Door........ These figures are based on the assumption that there is no wind pressure and-that swinging doors are in use in one wail only. Any swinging doors in other walls should be kept closed to. insure air conditioning in accordance with these recommended standards. - - b From Application Engineering Standards for Air Conditioning for Comfort 1947, Air Conditioning & Refrigerating Machinery Association, Inc.,- Washington, D. C. Used by permission. ' sash section in contact with steel work at mullions should be figured at 26 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.* 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-hung wood window may be used. If poorly fitted, twice this figure should be used. If Weatherstripped, the values may be reduced one-half. A single door 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 218 CHAPTER 10 1952 Guide 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. - Air Change Method . The amount of air leakage may be estimated by assuming a certain num ber of air changes per hour for each room, the number of changes as sumed being dependent upon the type, use, and location of. the room, as 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 other sources of air leakage cannot readily be evaluated, as is often the case, the use of the air change method may be justified.* The values in Table 4 may be used with reasonable accuracy for resi dences, and are the requirements for each room. The total infiltration allowance for the entire building should be one-half the sum of the infil- Table 4. Aik Changes Taking Place under Average Conditions in , Residences, Exclusive op Air Provided for Ventilation* Kind or 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:.__.1 i iM 2 2 Kind of Room or Building Rooms with no windows or outside doors___ Entrance Halls Reception Halls.. .......... Bath Rooms__ _ ......... .. Number of Air Changes taking Place per Hour M toM 2 to 3 2 2 less than i air change. tration allowances of the individual rooms, since whatever air enters-on the windward side, generally leaves the building on the leeward side, and the infiltration requirements therefore do not exist simultaneously on all sides, or in all rooms. An allowance of one air change per hour for all sources of air leakage for the entire volume may be considered average for a well constructed residence. . The air leakage, due to opening and closing of doors in vestibules, is sometimes based on the air change method, even though the air leakage estimates for other rooms are based on the crack method. Except for vestibules and reception halls, it is not advisable to attempt to apply the air change method to factories and industrial and commercial buildings, because .of wide variations in the type and percentage of fenestration which is- the principal source of- air leakage in such buildings. ' INFILTRATION DUE TO TEMPERATURE DIFFERENCE .The- air exchange due to temperature difference, inside to outside, is a chimney effect, causing,air. to enter through openings at lower levels, and to leave at higher levels.8 Although it is. not appreciable-in low buildings, this loss should be considered in tail, single story buildings with openings near the ground level and near the ceiling! Also in tall, multi-story, build ings it may be a considerable item, unless the sealing between various floors and rooms is quite perfect. V' -" : . In tall buildings, temperature difference or chimney effect will-produce Infiltration and Ventilation 219 a head that will add to the effect of the wind at lower levels, and subtract from it at higher levels. On the other hand, the wind velocity at lower levels may be somewhat abated by surrounding obstructions. Further more, the chimney effect is reduced in multi-story buildings by the partial isolation of floors, thereby preventing free upward movement, so that wind and temperature difference may seldom cooperate to the fullest extent! Making the assumption that the neutral zone7 is located at mid-height of a building, and that the temperature difference is 70 deg, Equations 1 and 2 may be used to determine an equivalent wind velocity to be used in connection with Tables 1 and 2, that will allow for both wind velocity and temperature difference: .. V. = Vv* i;75o . (1) . where . . Ve:= Vv + 1.755 . ' (2) Ve = equivalent wind velocity to be used in conjunction with Tables 1 and 2, miles per hour. ' V = wind velocity upon which infiltration would be determined if temperature / difference were disregarded, miles per hour. a = distance of windows under consideration from mid-height of building if above mid-height, feet." ' b = distance if below mid-height, feet. The coefficient 1.75 allows for about one-half the temperature difference head. For buildings of unusual height, Equation 1 would indicate negative infiltration at the highest stories, which condition may, at times, actually exist. . Sealing of Vertical Openings In tall, multi-story buildings, every effort should be made to seal off vertical openings, such as stair-wells and elevator shafts, from the remainder of the building. Stair-wells should be equipped with self-closing doors, and, in exceptionally high buildings, should be closed off into sections of not over 10 floors each. Plaster cracks ' should be filled. Elevator en closures should be tight, and solid doors should be used. If the sealing of the vertical openings is made effective, no allowance need be made for the chimney effect. Instead, the greater wind move ment at the greater heights makes it advisable to install additional heating surface on the upper floors above the level of neighboring buildings, this additional surface being increased as the height is increased. One arbi trary rule is to increase the heating surface on floors above neighboring' buildings by an amount ranging from 5 per cent to 20 per cent. 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 installations. , 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 of air makes it advisable to increase the amount of heating surface at the lower levels, and to decrease the amount at higher levels. One rule is to calculate the heating surface of the entire stair-well in the usual way, and to place 50 per cent of this in the bottom third; the normal amount in the middle third, and the balance in the top third. . 220 CHAPTER 10 1952 Guide Infiltration and Air for Combustion 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. NATURAL VENTILATION Ventilation by natural forces finds application in industrial plants, public buildings, schools, dwellings, garages, and in farm buildings. The natural forces available for moving air into, through, and out of buildings are: (a) wind forces, and (b) the difference in temperature between the air inside and outside a building. The air movement may be caused by either of these forces acting alone, or by a combination of the two, depending upon atmospheric conditions, building design, and location. The ventilating results obtained will vary, from 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, '. Values are given in Table 3, Chapter 12 for the average wind velocities for the months June to September in various localities throughout the United States, while Table 1, Chapter 11, 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 oner half of the average for many hours per month. Consequently, if the natural ventilating system is designed for wind velocities of one-half of the average seasonal velocity, it should prove satisfactory in almost every case. Equation 3 may be used for calculating the quantity of air forced through ventilation openings by the wind, or for determining the proper size of such openings to produce given results: . . where . Q = EAV , (3) . ' Q = air flow, cubic feet per minute. A = free area of inlet openings, square feet. , V = wind velocity, feet per minute, = miles per hour X 88. E = effectiveness of openings. (E should be taken at 0.50 to 0.60 for perpendicu- . lar winds, and 0.25 to 0.35 for diagonal winds.8) The precision of 'results obtained by the use of Equation 3, depends upon the placing of the openings, as the formula assumes that ventilating openings have a flow coefficient slightly greater than that of a square- Infiltration and Ventilation 221 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 usually well placed, the flow will be slightly more than that given by the formula. Inlets should be placed to face directly into the prevailing wind, while outlets should be placed in one of the five places listed: ' 1. On the side of the building directly opposite the direction of the prevailing wind. 2,.Dn the roof in,the low pressure area caused by the jump of the wind (see Fig,;2). 3. On the sides adjacent to the windward face where low pressure areas occur. Fig. 2. The Jump op Wind fbom Windward Face op Building. B(A--Length op Suction Area; --Point of Maximum Intensitt op Suction; C--Point of Maximum Pressure) 4. In a monitor on the side opposite from the wind. 5. In roof ventilators or stacks. . . ., TEMPERATURE DIFFERENCE FORCES7 The stack effect produced within a building, when the outdoor tempera ture is lower than the indoor temperature, is due to the difference in weight of the warm column of air within the building and cooler air outside., . The flow due to stack effect is proportional to.the square root of the draft ;head, or approximately . ..: . , Q = 9.4A s/h(l - to). . : (4) 222 CHAPTER 10 1952 Guide where 1 . : :' 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. . ' t = average temperature of indoor air in height ft, Fahrenheit degrees. t0 = temperature of outdoor air, Fahrenheit degrees. ' ' 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 ikfiltration and Ventilation 223 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- Fig. 3. Increase in Flow Caused by Excess of One Opening Oveb Anotheb air to be passed through the building per minute, to maintain this tempera ture difference, can be determined by means of Equation 5. where H 0.0175 (t - to) (5) Q = air flow, cubic feet per minute. ... H = heat removed, Btu per minute. . .. t -- to = inside-outside temperature difference, Fahrenheit degrees. . 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. Fig. 4. Detebmination of Flow Caused by Combined Fobces of Wind AND TeMPEBATUBE DIFFERENCE ' . 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 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, as a percentage, the ratio of the flow produced by temperature difference to the sum of the two flows, the actual flow due to the combined forces can be approximated from FiS-4-. . Example 1: Assume a drop forge shop, 200 ft long, 100 ft wide, and 30 ft high. .TJie cubical content is 600,000 cu ft, and the height of the air outlet over that of the ^ ^ 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- 224 CHAPTER 10 1952 Guide 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? 11 , . ,, 15 X 7.75 X 18;000 Solution for Temperature Difference Only: The heat/f.=----------. gg : -- 34,875 Btu per min. . . By Equation 5, the air flow required to remove this heat with an average temper ature difference of 10 deg is ' _____H ____ ' 34,875 199,286 cfm. 0.0175U - ii) ~ 0.0175 X 10 This is equal to about 20 air changes per hour. From Equation 4, the inlet (or outlet) opening area should be Q____________ 199,286 1224 sq'ft. 9.4Vh(t - to) ~ 9.4\/30 X 10. The flow per square foot of inlet or outlet would be 199,286 -s- 1224 -- 163 cfm, with all windows open. .;. Solution for Wind Only: With 1,224 sq 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. The outlet area will be equally distributed on the two sides of the monitor, or 612 sq ft on each side. With the wind perpendicular to the long side, there will be 410 sq 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 and 612 sq ft in the monitor, the flow will be increased 26.5 percent over that produced by equal openings. Using 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 times that calculated for temperature difference alone, or 201,920 cfm. _ ' The original flow, due to temperature difference alone, was 199,286 cfm with au openings in use. The effect of the wind is to increase this to 201,920 cfm, even though half of the outlets are closed. , ; A factor of judgment is necessary in the location of1 the openings in a. building, especially those in'the roof; where heat, smoke, and fumes are to be removed. Usually, windward monitor openings should be closed, but if the wind is low enough for the temperature head to overcome it, all windows may be opened. TYPES OF OPENINGS ' Types of openings may be classified as: (1) windows, doors, monitor openings and skylights; (2) roof ventilators; (3). stacks connecting to Infiltration and Ventilation 225 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 Windows have the.advantage of transmitting light, as well,as providing ventilating area, when open.. Their movable parts are arranged to open in various ways; they may open by sliding either vertically, or horizontally, by tilting on horizontal pivots at or near the center, or by swinging on pivots at the top, bottom or side. Regardless of their design, the air flow per square foot of opening may be considered to be the same under the same conditions. The type of pivoting should receive consideration from the standpoint of weather protection, and certain types may be ad vantageous in controlling the distribution of incoming air. Deflectors are sometimes used for the same purpose, and these devices should be con sidered a part of the ventilation system. - 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 perature head which create flow through other types of openings. The capacity of a ventilator depends upon four things: (1) its location on the 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 energy of the wind for inducing flow by centrifugal or ejector action For maximum flow induction, a ventilator should be located on that part of the roof where it will receive the full wind without interference. If ventilators are installed within the suction region created by the wind passing over the building, .'or. in a light court, or on a low building between two high buildings, their performance will be seriously influenced. Their normal ejector action, if any, may be completely lost. - ': The base of the ventilator should be of a taper-cone design to produce the effect of a bell-mouth nozzle whose coefficient of flow is considerably higher than that of a square-entrance orifice. If a grille is provided at the base, or if the base or structural members present obstructions, addi tional resistance is introduced, and the base opening.should be increased in size accordingly. .. Air inlet openings located at lower levels in the building, should be at least equal to, and preferably larger than,, the combined throat areas of all roof ventilators. The air.discharged by a roof ventilator depends on wind velocity and temperature difference, and, in general, its performance will be the same as any monitor opening located in the same place but, due to the four capacity factors already mentioned, no simple formula can be devised for expressing ventilator capacity. .. : Roof ventilators may be classified as stationary, pivoting or oscillating, and rotating. Generally, these have a round throat, but the continuousridge ventilator would fall in the stationary classification. When selecting roof ventilators, some attention should be given to ruggedness of construc 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 *n 226 CHAPTER 10 1952 Guide Infiltration and Ventilation 227 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 -, Slacks 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. 10. In case it is intpossible 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. Tfie"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 rrina 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 suc 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 flow through the zones ' to be ventilated.' , 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 fop. 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. '. Fig. 5. Recommended Type op Cover fob Wooden Outlet: Flue *1ii .flj 3. Greatest flow per square foot of total opening is obtained by using inlet and out . The opening H should equal one-half the least dimension of the flue. Heavy insulation of the level deck let openings of nearly equal areas. is essential. . _ .. 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 and grouping of ventilation openings, can be readily arranged to take full advantage VENTILATION OF ANIMAL SHELTERS* 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 Animal shelters require ventilation to remove moisture, odors and, in the. case of dairy stables, excess heat. . to a suction force, and effective movement through the bmlding-will be assured. Outlets. Outlet flues for natural draft systems should be round or . 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. approximately square. A thermal resistance (1/17) of not less than two is required in their side walls. They should extend at least two feet 6. In order that temperature difference may produce a motive force, there must be vertical distance between openings. That is, if there are a.number of openings avail able in a building, but all are at the same level, there will be no motive head produced by temperature difference, no matter how great that difference might be. 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. 7. In order that the force of temperature difference may operate to maximum ad vantage, the vertical distance between inlet, and outlet openings should be as great as possible.. Openings in the vicinity of the neutral zone are less effective for ventila 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 tion. . dimension of the flue, Fig. 5. A level, heavily insulated ceiling under the 8. In the use of monitors, windows on the windward side should usually be kept closed, since, if they are open, the inflow tendency of the wind counteracts the outflow tendency of temperature difference. Openings on the leeward side of the monitor flue roof, and over the entire area of the flue, is important. Inlets. Inlets should direct the incoming air vertically upward so as result in cooperation of wind and temperature difference. to avoid drafts on the animals, and to insure immediate mixing of incoming 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 air with the room air. A reasonably uniform distribution around the ing wind. The strong suction effect of the wind at the roof near the windward end stable or pen is desirable. Inlet flues, that deliver air close to the side walls, '1 will then cooperate with temperature difference, to provide for the most active and stimulate convection currents, which is desirable. Whensoplaced, they also satisfactory removal of the heat and gas-laden air. ' 228 CHAPTER 10 1952 Guide tend to bathe the side walls with cool air, thus reducing temperature differ- . ence between the inside and Outside of the wall. From the standpoint of air movement, insulation of inlet flues is not important. Condensation is, however, likely to occur on them, unless the thermal resistance of their walls is at least two! r Controls or throttling devices in inlet flues are seldom required. If .used, they are best applied to the inlets and limited to the side of the building facing prevailing winter winds. They should be so made th^t an opening, at least one inch wide by the width of the'flue, will always remain open. . ... Amounts of heat and water produced by livestock vary not only with the different kinds of animals, but also with age, weight, feed consumption' and production. These facts, and the vagaries of the weather, make exact 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 for. 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 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 pen stables or loafing bams in which there is a thick manure and bedding pack on the floor, and in which doors are normally kept open. . Outlets. One flue will serve a stable 200 ft long. In stables over 120 ft long, the flue should be about midway.between the ends or, if the stable is L^shaped, near the angle. In shorter stables, it may be at any con venient location. : ' The exhaust point in the stable should be not more than 18 in. abovethe 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 ' : i76 N iAo =. Vh (6) where A ,, = area of the outlet flue; square inches. ' N = weight of animal population, thousands of pounds.-. h = vertical distance from top of inlet flues to top of 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. Infiltration and Ventilation 229 Example 2: Assume a stable in which the vertical height from the top.qfthe inlets to the top of the outlet flue is 32.5 ft, and in which 38 cows, averaging 1300 lb, will be housed. Determine required size of outlet flue. ', - Solution: From. Equation 6 176 X (38 X 1.300) A. = = 1525 sq in. V32A 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 im below the ceiling. Sheep Bams : . 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 Fio. 6. Modification of Flue Areafob Outlets Exceeding 1000 Sq In. 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: 1 '' ' ' '. " i-- . ; where - : . A0 = area of the outlet, square inches.. " At,-- 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 of the manure pack. ' '- Inlets. Provide one inlet, 60 sq in. in area, for each 150 sq ft of floor area. Inlets should be. well distributed around the side walls, and de signed to deliver air near the ceiling (see section on Dairy Stables). . . 230 CHAPTER 10 1952 Guide Swine Barns ' .' 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 wfiTch 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 bams that are well stocked and adequately ventilated, this requires walls with an overall thermal resistance of from 3 to 6, and celings 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. j 2.5 X A, Ao= 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 area may be equal to 70 percent of the outlet area. Inlets in cold and in warm houses should deliver air from points 12 to 24 in. above the floor. In cold houses which normally do not have storm sash, windows may be raised enough to give the desired area, and be fitted with baffle boards to direct the air straight and upward. . In houses less than 20 ft in width, all inlets may be on one side. In wider houses, a rather uniform distribution of inlets is essential. Infiltration arid Ventilation 231 GARAGE VENTILATION . Because of hazards resulting from carbon monoxide and other physi 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. As cold weather, sets in, more and more of the ventilation openings are closed, and consequently bn extremely cold days, the carbon monoxide concentration runs high. .. ' Many garages can be satisfactorily ventilated by natural means, par ticularly during the mild weather, when doors and windows can be kept open. However, the A.S.H.V.E.' Code of Minimum Requirements for Heating and Ventilating Garages, adopted in 1935, states that natural ventilation may be employed for the ventilation of storage sections where it is practicable to maintain open windows or other openings at all times. The code specifies that such openings shall be.distributed as uniformly as possible in at least two outside walls, and that the total area of such open ings 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 removal of the same amount and its discharge to the'outside as a' means of flushing the garage.10 Research ' Cooperative research on garage ventilation, undertaken by the, A.S.H.V.E. Committee on Research at Washington University, St. Louis, . Mo., and at the University of Kansas, Lawrence, Kans., and tests con ducted at the A.S.H.V.E. Research Laboratory, have resulted in authorita tive papers on the subject. Some of the conclusions based on work at the Laboratory 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. , ' 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 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 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.S.H.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. 232 CHAPTER 10 1952 Guide 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, JVol. 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 Weathertightness of Rolled Section Steel Win dows, by J. E. Emswiler and W. C. Randall (A.S.H.V.E. Transactions, Vol. 34, 1928;p. 527). Pressure Differences Across Windows in Relation to Wind Velocity, by J. E. Emswiler and W. C. Randall (A.S.H.Y.E. Transactions, Vol. 36, 1930, p. 83)., 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, pi 169). ' * Fuel Saving Resulting from the Use of Storm Windows and Doors, by A. P. Kratz and S. Konzo (A.S.H.V.E. Transactions, Vol. 42, 1936, p. 87). The Infiltration Problem of Multiple Entrances, by A. M. Simpson and K. B. Atkinson (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, June, 1936, p: 345). Infiltration Characteristics of Entrance Doprs, by A. M. Simp son (Refrigerating Engineering, June, 1936). .. ` Indices of Air Change and Air Distribution, by F. C. Houghten and J. L. Black- shaw (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 261). . 8 A.S.H.V.E. Research Reports No. 994--Wind Velocities Near a Building and Their Effect on Heat Loss, by F. C. Houghten, J. L. Blackshaw and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 40,1934, p. 387). No. 1069--Heating Requirements of an Office Building as Influenced by the Stack Effect, by F. C. Houghten and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 43, 1937, p. 437). Flue Action in High Buildings, by H. L.. Alt (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, May, 1932, p.. 376). Influence of Stack Effect on the Heat Loss in Tall Buildings, by Axel Marin (A.S.H.V.E. Transactions, Vol.. 40, 1934, p. 377). 7 Neutral Zone in Ventilation, by J. E. Emswiler (A.S.H.V.E. Transactions! Vol. 32,1928, p. 59). 8 Predetermining Airation of Industrial Buildings, by W. C. Randall and E. W. Conover (A.S.H.V.E. Transactions, Vol. 37, 1931, p. 605). 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. 315). .. 10 Code of Minimum 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). CHAPTER 11 HEATING LOAD General Procedure, Design Outdoor Weather Conditions, Inside Temperatures,^ ` Attic Temperatures, Temperatures in-Unheated Spaces, Ground Tempera-'- tures, Basement: Temperatures and Heat Loss, Floor Heat" Loss in Base- - mentless Houses, Transmission':Heat Loss; Infiltration Heat Loss, Se- :: , ' lection of Wind Velocities', Auxiliary Heat Sources; Intermittently . > 1 Heated Buildings, Residence Heat Loss Problems '*< PRIOR to designing a' heating system, an estimate must be made bf the maximum probable heat 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 diyided.into two groups, namely : (i) the transmission losses or heat transmitted through the confining walls,.floor, ceilmgr^glass or Other surfaces; and (2) thp in-; filtration losses or- heat required to warm outside air which leaks in through cracks and crevices, arouM doors and:windows, opening of doors and;windows, .or heat required to warm outside, air. qspd,for ventilation. GENERAL PROCEDURE , 1 The general prdredure'fpr'calcuSiting heat losses of a structure;is: , 1.Select the-design outdoor weathe'r conditions ^temperature, wind direction ana* wind velocity. The data on climatiC condrtions given in Table 1 ahd the isotherms of average design temperature iUiFig,'T-wiH be helpful, `.but should be used with judgr, mept. 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 T.ables2)''[' , , . / . ,, 3.Estimate temperatures in adjacent unheatOd .spaces ahd,the. attic.. The attaq temperature need not be estimated if the combined roof and ceiling coefficient Utised.: 4: Select bKcOinpute the heat transmission coefficients for outside walls and glass;' also for inside walls, floors, or top-floor ceilings; if -these are next to uhheated spaed; include roof if next to heated space, . (See Chapter 9). - 5.Measure net drea 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; made 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 by the area of the surface in square feet, and the temperature difference between the inside and outside air. (See-ItOms 1, 2; and 3). '': ' - ' ' > ` '! 7; Select unit valuesnnd cb&'pute" 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 expressegthe heat required to warm up the cold air leaking into the building per hour". (See Chapter 10): 8. When positive ventilation using outdoor air is provided by an air heating or an air 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 amount 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 outdoor air supply equals or exceeds the amount of natural infiltration which would 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 ' " . ' -233 " ' - ..: . - 234 CHAPTER 11 1952 Guide (Item 7) of the cold air entering by infiltration, or required to replace mechanical exhaust, represents the total heat loss equivalent for any building. DESIGN OUTDOOR WEATHER CONDITIONS There are no hard and fast rides 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 and experience. The outside, design, temperature seldom is taken as the lowest temperature, 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 prevailing at the time of design outside conditions frequently are entirely different from those prevailing 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 data of this nature are not available, but Column 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 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. Because of the limited data available, design temperatures in common use are listed in Column 10. Many of these values were furnished by A-S.H.V.E. members--the balance were taken from an ACRMA Bulletin,1 manufacturers' publications and other sources,1 and a few were estimated. The map. Fig. 1, shows isotherms approximated for these design tempera tures. They may be used as a guide for localities not listed in the table. Interpolation between these lines is suggested, and due consideration must be given to elevations and other local conditions. Large differences in climate occur within relatively small distances of Weather Bureau stations in hilly and mountainous regions. Experience and judgment are necessary to deal properly with this factor. Column 8 of Table 1 gives the maximum wind velocity which occurred with temperatures the same as, and lower than, those shown in Column 8. Winter average velocities for all temperatures are given in Column 11. Column 6 lists the average annual minimum temperature which is the average of readings of the one lowest temperature occurring for each year the station has been in existence. It is of interest as a guide to the lowest temperature to be expected, except for an occasional extreme of short duration; 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 Heating Load 235 Table 1. Winter Climatic Conditions* ` Col. 1 Col. 2 State Station1* Col. 3 Ele va tion* FT Col. 4 Period or Record0 Col. 5 Low est Temp. on Rec, ORD F Col. 6 ; Aver age An-' NUAL Min. Temp.* F Col. 7. Ava.. WlN' TER Temp/ F Col. 8 Col. 9 Col. 10 Col. 11 Design Design DrtBulb Temp. onTAC 97*% Wind VeL. AT Design TEMP.b Dry- Bulb Temp. IN ` Common Basis Use1 v Avo. Wind Vel. Dec. Jan.. Feb.J *F Mph F Mph Ala.... Anniston...................C 733 Birmingham- f1 - 711 1893-1947 1893-1945 Birmingham............A 615 1939-1947 Mobile../'... ___ C 143 1872-1947 Mobile........................A 219 1940-1947 Montgomery.;........ C 293 1872-1947 Montgomery............A 226 1938-1944 Arts..:. Flagstaff....................C 6957 1899-1947 Kingman.................. A 3473 1935-1939'* Phoenix..................... C 1122 1895-1947 Phoenix...:............ A 1112 1937-1947 Tucson.......................C Up to 1946 Tucson....................... A 2561 1935-1939'*. Winslow.....................C 4853 Up to 1946 Winslow.................... A 4899 1932-1947 Yuma.........................C 146 1876-1946'* Ark.i.. Fort Smith.............. C 545 1882-1945 FoH Smith;............ A 463 1945-1947 little Rock..........: .C 451 1879-1942 Little Rock..............A 282 1942-1947 Cal.... Bakersheld...............A 499 1937-1946'* Burbank................... A 740 1931-1947 Davvett ...................A 1925 1935-1939'* Eureka....................... C 115 1886-1947 Fresno........................ C 387 1887-1939 Fresno........................A 281 - 1939-1947 Los Angeles............. C 534 1877-1947 Oakland.................... A 21 1929-1947 Red Bluff................. C 341* 1877-1934 / Red Bluff....'........ A 346 1944-1947 Redding.................... A 579 1935-1939'* Sacramento.-.::... .C 116 ! 1877-1947 Sacramento..............A 22 1938-1947 San Diego.................C 90 1871-1940 San Diego.................A 34 1939-1947 San Francisco.........C 164 1875-1947 San Jose.................... C 100* Up to 1945 Williams.................... A 124 1935-1939'* (Jol... t Denver.............. ;.. .C 5398 1871-1947 Denver.................. . .A 5379 1934-1947 Grand Junction.. .C 4587 1889-1945'* Pueblo....................... C 4770 1889-1938'* Pueblo....................... A 4810 1939-1947 Conn.. Hartford................... C 229 1905-1940 Hartford..................A 20 1940-1947 New Haven.............C 180 1872-1946'* New Haven.............A 17 D.C... Washington..............C 128 1943-1947 1871-1947 Washington..............A 20 1935-1939 Fla... Apalachicola............C 23 1922-1947 Jacksonville.............C 104 1871-1947 Jacksonville.............A 29 1938-1947 Key West................. C 23 1871-1947 Key West................. A 48 1939-1947 Miami........ :..............C 253 1896-1947 Miami ....................... A 13 1940-1947 Pensacola..................C 67 1879-1947 Pensacola.................. A 113 1943-1947 Tamr>a....................... C 111 1890-1940 Tampa....................... A 12 1941-1946 Titusville..................A 52 Ga..... Atlanta...................... A 1020 1935-1939'* 1878-1945'* Augusta.....................C 195 1871-1946'* Augusta.....................A 424 1939-1947 Macon.........................C 408 1899-1947 Macon.........................A 432 1939-1947 Savannah................. C 115 1871-1945 Savannah . .............A 56 Idaho.. Boise........ ..................C 2818 1939-1947 1864-1939'* Boise........................... A 2849 1939-1947 Burley........................ A 4150 1935-1939d Idaho Falls.............. A 4744 1935-1939** Lewiston................... C 763 1900-1944 Pocatello...................C 4522 1899-1947 111.. Pocatello..:.............A 4467 1938-1947 Chicago..................... C 601* Up to 1946 -10 -10 -10 -1 13 --5 9 -25 8 16 21 6 19 -19 -18 22 -15 7 -12 7 19 21 20 17 23 28 23 17 25 17 17 22 25 ' 34 ' 27 . 22 -29 ' -30 -21 -27 -26 -18 -24 -15 -4 -15 18 10 16 41 42 27 28 7 20 19 31 -8 3 10 7 8 8 16 -28 -13 --35 -18 -23 -28 -23 -23 12 22 18 19 -15 26 -1 27 6 10 25 29 26 37 28 37 37 -11 -2 -1 -1 29 38 35 23 32 12 22 -1 1 -12 -8 52.3 53.8 51.8 58.9 56.4 21 30 35.9 59.5 57.7 57.2 57.2 43.6 43.5 62.5 50.4 22 . 31 ,30 6 51.6 21 .55.5 33 57.5 35 .27 49.3 53.8 . 32 59.3 51.9 36 63.9 52.9 32 53.0 58.2 54.2 53.5 39.0 37.0 39.9 41.1 36.4 38.4 . 43.4 60.9 62.0 60.6 73.1 72.5 71.4 59.7 43 29 0 2 4 11 14 31 45 66.0 51.3 54.2 38 22 64.7 68.5 66.7 40.3 39.8 36.9 42.7 37.1 35.0 * 29 5 .2 -7 6 37.6 5 10 8.0 7.4 15 9.9 8.5 10 7.5 -10 7.7 8.6 25 5.4 5.6 25 5.3 6.3 -10 7.5 - 30 6.7 . 10 8:3 5 8.3 ' 6.6 5.6 ' 25` 4.9 8.5 - 30 7.3 25 5.4 4.5 35 . 6.4 7.6 30 6.1 7.1 30 7.2 -35 5.8 35 ' 25 8.3 -10 8.8 -15 -20 6.4 0 8.3 0 8.1 . 1 0> 7.4 25 25 7.0 45 6.3 7.5 7.5 ' 4.4 7.9 8.7 9.4 7.8 8.4 9.0 10.6 35 10.1 7.3 20 10.9 30 8.6 6.5 10.2 10 11.7 10 6.5 15 6.7 20 9.5 7.7 -10 9.1 4.5 8.8 7.6 5 4.1 -5 8.9 7.2 9.8 -10 12.0 Blank spaces indicate data not yet completed. 236 CHAPTER 11 /- 1952 Guide Table 1... Winter Climatic Conditions"--(Continued) Col. 1 State Col. 2 Station!* . Col. 3 EleVA TION FT Col. 4 Periop RECORD* Col. 5 LowEBT Temp, on Rec ord* ' F Col; 6 Col. 7 Col. 8 Col. 9 Col. 10 Col. 11 Aver age. / An nual Min. Temp.* ,Avg. . Win ter Temp. . Design Dry.Bulb' -Temp, on TAC 97i% -Wind Vbl. at Design Temp.1* Basis8 Design DryBulb Temp, in Commpn Use' i Avg. Win Vel. . Dec. ! Jan.. : Feb.j : F F- F Mph F ; Mph 111..... Chicago...................A 615 1935-1939*! Moline..'................ A 564 1935-1939-! Peoria......................A 660 1935-1939** Springfield............. C 603 1879-1947 Springfield............. A 608 1930-1947 Ind.... Evansville.............. C 464 1897-1940 Fort Wayne............C 885 1911-1941 -Helmer.................... A 970 1935-1939d -Indianapolis.'......... C 816 1871-1946* Indianapolis........ A 800 1932-1946* Terre Haute...........C 1146 1893-1946d Terre Haute...........A 589 Charles City.....- .C 1023 1891-1945** Davenport.-............C 648 1872-1947. Des Moines............ C 805 1878-1945* -Des- Moines............ A 979 1935-1939** 740 1874-1947 ;Keokuk..................C 637 1871-1945** Sioux City.:.;-....... C 1093 1880-1944 Sioux City.-........ .-.A 1098 1940-1945** Kan... Concordia............... C 1425 1885-1947 Dodge City............C 2515 1942-1947 Dodge City............A 2599 1874-1942 Topeka.................... C 991 1887-1947 Topeka....... . :........A 883 1946-1947 -Wichita....................C 1497 1888-1930 Wichita................... A 1423 1939-1047 Ky.... Louisville................C ' 563 1871-1047 Louisville................A 544 1937-1047 La....... New Orleans;.........C 85 1874-1947 New Orleans..........A 8 1937-1047. Shreveport............. A 179 1935-1939* Maine. Eastport..................C 100 1873-1947 Portland.. ........... C 70 1885-1940 Portland..................A 66 1040-1947 Md.... Baltimore............... C 114 1871-1947. Baltimore...........A 43 1935-1939* Mass... Boston.....................C 356 1870-1935* Boston.....................A 45 1936-1947 Nantucket..............C 45 1886-1947 Nantucket..............A 48 1946-1947 Mich... Alpena-----;.C 615 Up to 1946 Detroit.................... C 1000 . 1873-1933. Detroit........ A 632 1935-1939* Rscanaba..............' .C 645 1878-1945** Grand Rapids..... C 708 1891-1946* Lansing. -.............;.. U 861 1910-1947. TAnniiig....-........... A 863 1940-1947 Marquette............ .- .C 721 1874-1947. Sault St. Marie___ C 724 1888-1942* Minn... Duluth...................... C 1133 1874-1947 Duluth................ . .A 1413 1941-1947 -Minneapolis.............C 945 1890-1947 Minneapolis.........;. A 873 1935rl947 .St. PauK....... '... .C 951 1871-1933 St.' Paul.................; .A 708 1937-1947 Miss... .Meridian................... C 410 1889-1947 Meridian................... A 298 1939-1947 I Vicksburg...............C 316 1874-1947 Vicksburg.............: .A 266 1941-1947 Ho. Columbia..:........ : .<3 739 1889-1947 -Columbia................. A 787. 1939-1947 Kansas City............C 741c 1889-1940. Kansas City........: .A 780 1935-1939* St. Louis...................C 646 j - .St. Louis___ '...........A 597 1871-1947 1930-1947 1270 1935-1939* Mont... : Billings................... A 3584 1935-1939* Butte..........................G 5700 1894-1931 Butte..........................A 5538 1931-1947 -Havre....... ...-.........C 2498 1880-1947 Helena.................. .C 4175* 1880-1940* i Kalispell................. C 3004 1897-1947. 'Miles City............. C 2400 1892-1942* Miles City.............. A 2629* 1935-1939* Neb.... Lincoln....................C 1189 1887-1947 -24 -19 -16 -24 -25 -18 -18 -11 -34 . 27 . -30 -32 -27 . -35 -24 -25 -26 -26 -25 -21 :--22 -10 -20 -15 ; .7 19 --23 -21 39 -7 -18 -14.. -8 12 . -28 . -24 -32 . -24 -25.. --10 -27 -37 -4i -33 -34 -31 -41 -26 ' -6 : -7 -1 10 -26 -18 -22 -22 -19 -34 -52 -57 -42 -34.. -49 -29 . 35.1 34.6 37.3 --7 39.8 37.7 1 45.1 . 37.6 -6 39.6 39.0 -5 41.7 -22 31.2 -13 * 37.0 36.4 35.4 -17 34.6 -12 *39.3 -20 . 32.6 -13 40.7 -10 41.4 42.1 ; -4 43.6 -5 45.1 43.9 26 61.6 60.6 16 --15 31.5 -6 33.8 33.0 8 44.3 44.1 -3 38.1 39.3 -12 29.6 -11 36.5 27.3 36.0 34.0 -13 28.3 -22 26.0 -28 24.3 -23 29.4 -25 :-i8 15 29.0 54.8 18 ' -6 56.8 53.6 42.3 41.1 41.5 -2 -5 -30 -36 -24 -17 -30 -13 43.6 42.3 34.9 30.7 27.0 28.4 31.6 31.6 29.0 '27.6 37.0 -3 -6 -6 -2 -1 2 -8 6 9 36 27 13 .8 4** -15 2 3 8 -17 -18 -18 11.7 , 10.8 10.7 11.6 11.5 11.4 -10 -10 .-^10 8.3 11.9 9.6 -10 ' 10.4 ' -10 : 11.3 10.2 14.5' -15 -15 -20 . -20 7.9 10.5 . 10.1 7.1 8.3 . 11.5 -16 7.7 -10 10.6 -10 9.2 14.7 8.8 12.8. ' 8.9 . -10 12.4 0 r 20 9.8 8.6 . 20- 8.8 -10 12.6 -5.- . 10.4 0 . 8.2 8.9 .0 12,4 * 12.3 . 0 14.8 -10 11.0 -10 12.0 11.0 -15 9.5 -10 12.1 -10 . 9.8 -10 10.6 -20 8.9 -25 13.4 -20 11.3 ^20 : 9.5 9-9 . 10 . 6.3 10 8.3 -10 8.9 -10 10.3 10.6 .0 11.8 10.8 11.0 11.0 9.1 -25 12.4 -20 4.8 -30 9.4 -20 . 7.4 -20 5.2 -35 5.6 8:4 -10 10.6 Approximate value. . Heating Load 237 Table 1. Winter Climatic Conditions"--(Continued) Col. 1 State Col. 2 . Station1* -" Col. 3 Eletion* FT Col. 4 Period Record*- Col. 5 Low EST Temp. ON . Rec ord*' F Col. 6 Aver age An- nual Min: Temp* F Col. 7 Col. 8 Col. 9 Col. 10 Col. 11 Avg. WinTER Temp.' Design Design DryBulb Temp, on TAC 974% Wind. Vel. at Design Temp.1* Dry- Bulb Temp. IN Common Basis8 Use* Avo. Wind. Vel. Dec. Jan. Feb.J F. F Mph F Mph Neb... Lincoln___..... ..A 1185 1933-1947 North Platte... ..C 2815 1874-1947 North Platte... ..A 2788 1935-1939** Omaha............... ..C 1219 1873-1935 Omaha......... . 1009 1935-Pres. Valentine........... ..C 2627 1889-1947 Nev.... Elko.................... ..A 6079 1935-1939* las Vegas.......... A 1882 1937-1947 Reno.................. ..C 4588 1905-1942 Reno.................. A 4417 - 1940-1947 Winnemucca__ G 4293 1871-1947 N. H... Concord............. ..c 343 1871-1941 Concord___ .... A 359 1941-1947 N. J... Atlantic City... .-.C 45 1874-1947 Camden............. ..A 20 1935-1939** * Newark......... ..A 15 1931-1947 Sandy Hook__ c 19 1914-1938** Trenton............. c 144 1866-1946 N.M... Albuquerque... ..c 5022 1931-1933 Albuquerque... ..A 5319 1935-1947 ElMorro............ ..A 7120 , 1940-1947 Rodeo. ............. ..A 4116 1935-1939** Roswell.............. ..G 3643 .1905-1947 N. Y... Tucumcari........ . A Albany............... ..C 4054 . 114 ' .1935-1939* 1874-1947 Albany............... A 280 .1938-1947 Binghamton___` ..c 915 1891-1946 Binghamton-- ..A 836 - 1942-1947 Buffalo.......... ..o 693* 1873-1945** Buffalo............... A 726 : 1935-1939** Canton............... ..c 458 . 1889-1947 Elmira................. ..A 948 1935-1939* Ithaca................. G 888 1879-1937 G 425 1871-1947 Oswego...:. ----- G 363 1871-1943 Rochester............ ..G 609 1872-1947 Rochester. ..A 560 1935-1939** Syracuse.......... : *. ..G 465 1928-1940 A 404 1940-1947 N. C... Asheville............. ..O 2280 1902-1947 Charlotte............. ..G 809 1878-1947 Charlotte............. ..A 757 ' 1939-1947 -26 -35 -32 --21 -38 8 -19 -16 -36 -35 --37 --9 -14 -11 -14 5 -6 -25 -29 -24 -22 -28 -17 -20 -43 -24 -14 -23 -i 22 --16 -24 -26 -6 -5 -3 Raleigh.............. '. C Raleigh.............. : ..A Wilmington........ G N. D... Bismark............... ..G Bismarck............. ..A Devils Lake....... ..G Dickinson........... ..A Fargo..................- ..A Pembina............. A Williston............. G Ohio... Akron................. ..C Akron................... ..A Cincinnati........... ..G Cincinnati........... ..A Cleveland............ ..C Cleveland........... ..A Columbus........... ..G Columbus.-......... A Dayton...: .. ..G Dayton..... .......... ..A Sandusky.......... '. ..G Toledo................. ..c Toledo.... r-___ ' ..A Okla... Ardmore.............. ..A Oklahoma City.. ..C Oklahoma City. ..A Tulsa ..A Waynoka............. ..A Ore.... Arlington............ A Baker................... ..G Baker................... ..A Eugene...............'. ..G Eugene....... ....; ..A Meaford......... ..G 405 1944-1947 446 1935-1939** 78 1871-1947 1675 1875-1940 1855 1940-1947 1481 - 1904-1947 2599 1935-1939** 900 1935-1939** 830 1935-1939** 1919 1879-1947 1887-1931** 104 1935-1939** 772 1870-1947 488 1931-1947 669 1871-1946** 813 1930-1946** 812 .1878-1946** 820 1939-1947 1086 1883-1943 1002 1940-1947 608 1878-1946** 668 1871-1947 626 1940-1947 762 1935-1939** 1264 1890-1947 1311 1939-1947 686 1932-1947 1529 1935-1939** 881 1935-1939** 3501 1889-1947 3374 1939-1947 366 1890-1942** 368 1942-1947 1428* .1911-1929 -2 5 -45 -38 -46 -50 -20 -17 -14 -17 -5 -20 -15 -28 . -11 -16 -16. -13 -17 -10 -5 -25 -19 -4 9 1 -10 -17 -14 -22 16 --10 -15 6 2 -19 , - : _n --4 -26 --10 -3 . --4 :6 12 13 18 -31 -:33 -2 -2 : -3 1 ' -5 2 -17 35.6 35.4 36.4 33.6 , 53.8 41.7- ' 38.0 ,33.2 42.3 41:2 42.0 44.3 -. 10 16 51.4 . 49.1 35.2 34.7 . 13 :0 34.8 ' 29.5 .34.9 41.1 . 34;4 35.1 5 34.8 46.1 50.6 50.0 54.6 25.3 22.9 21.7 25.6 24.5 37;3 .43.0 . 37.2 40.4 38.'2 40.4 -1 22 17 20 .-24 f -20 -25 -30 9 7 6 ' ;4 38.0 37:2 35.7 47.9 49.0: 35.2 33.8 . 45.9 45.4 . 44.7 :4 18 14 13 10 7 3 23 12.7 -20 10.7 -10 . -25 5.3 3.6 -15 11.6 7.1 ' 8.4 .. -10 9.2" -10 9.6 -10 14.0 -25 8.0 -rl5 11.9 -10- 7.5 7.8 8.5 7.1 12.4 10.9 11.9 10 . 10 . -30. -30 -25 10.6 8.0 13.8 10.5 12il 9.7 14.7 11.3 11.3 7.8 6.4 5.3 -10 0 *0 " -10 0 -5 15 .5 7.9 9.7 9.2 6.0 8.1 6.2 15.8 .7.3 7.1 10.5 6.8 17.1 10.5 11.3 11.2 7.3 7.9 9.1 10.1 8.6 ` 8.5 14.7 11.6 11.1 11.0 12.1 11.5 5.6 4.3. 238 C H/AP^ TER 11 ' 1952 Guid'e Table 1. Winter Climatic Conditions*--(Continued) State Col. 2 Station1* .- t Col. 3 Ele va tion* ft Col. 4 Pbbiod - Col. 5 Low EST Temp. on Rec ord F Col. 6 Aver age . An nual Min. Temp. F Col. 7 Col. 8 Col. 9 Col. 10 Col. 11 Design Design Avo. Win- ! . TER Temp.* Dbt-. Bulb Temp. onTAC 97 Wind. Vel. AT Design Temp.*1 DbyBulb Temp. IN COMMON Basis* Use1 Avg. Wind Vel. Dec. Jan.. Feb.* F F Mpb F Mph Ore.... Medford___ ____ ...A 1343 1929-1947 Portland............ .. c 98 ' 1874-1947 -3 -2 Portland....... ...A 25 1940-1947 3 Roseburg........... ..C 523 1877-1947 -6 Pa....... Curwensville... A 2219 1943-1947 -10 Erie.................... ...C 771 . 1873-1946. -16 Erie ....... ........... ...A 736 1935-1939. Harrisburg-.-.... ...c 335f 1888-1938. -14 Harrisburg........ ...A 339 1935-1939 Pa....... Philadelphia:... ...C 200 1871-1947 Philadelphia ...A 18 1940-1947 -11 1 Pittsburgh........ ...C 929 1875-1947 --20 Pittsburgh........ A 1284 1935-1947 -16 Reading............. , C 311 1913-1947 -14 ...c 877 1901-1947. -19 Sunbury............ ...A 448 1935-1938d R. I..., Block Island... r. 46 . 1881-1947 -10 Providence........ c 77 ; 1904-1947 -17 S. C... Charleston........ ...c 59 1871-1947 7 .Charleston..... A 51 1940-1947 14 Columbia... ...C 401 1887-1947 -2 Columbia ...A 227 1939-1947 9 Greenville......... C 1006 Up to 1946 -5 S. D... ...C 1342 1881-1938 -43 .Huron................ A 1287 1938-1947 ; -30 Rapid Citv....... ...C 3309 . 1887-1947 -34 Rapid City....... ...A 3220 1939-1947 1 -r27 Te[ n,ni ... Chattanooga... .. C Chattanooga... ...A -952 675 1879-1947 : -10 1940-1947 6 Knoxville........ ...C 1024 1871-1942 ' Knoxville.......... A 1007 1942-1947 -16 1 Memphis.......... ...C 348 1872-1941 -9 Memphis............ . A 267 1 1941-1947 .1 Nashville........... ...C 714 - 1871-1947 -13- Nashville:......... A 610 1939-1947 -15 Texas.. Abilene.-............ ...C 1748 ' 1885-1944 -6 Abilene............. , A 1756 1940-1947 -9 Amarillo.......... . .0 3686 * 1892-1941 -16 Amarillo........... A 3595 1941-1947 -7 Austin................ ...C 625 1897-1942 -1 Austin................ A 625 1942-1947 13 Brownsville.... ...C 140 1922-1943 12 Brownsville.... A 25 1943-1947. 30 Corpus Christi. C 21 1887-1942d 11 Corpus Christi. 'A 45 I943-1948d 23 ' Dallas............... ...C 732 1913-1940 -3 Dallas............... Del Rio...'___ , cA 520 1020 l 1940-1947 1905-1947 5 12 El Paso............ ...C 3792 1880-1942 -5-' ...A 3956 1939-1947J 11 Fort W'orth. C 708 1898-1939d -8 Fort Worth....... A 728 1940-1947 4 Galveston........ ...C 128 1871-1947 8 Galveston....... ...A 9 1939-1947 14 ...C 198 1888-1947 5 A 73 1932-1947 5 Palestine.......... C 555 1881-1947 -6 Port Arthur... ...C 64 1917-1947 11 A 21 1944-1947 24 San Antonio... ...C 770e 1885-1941 4 San Antonio... ...A 800 1942-1947 17 ...A 513 1931-1947. 7 Wink................. ...A 2811 1935-1939 Utah.. Milford........... . 1 A 5095 lMS-lSST1 -17 C 5472 1901-1947 -32 Salt Lake City ...C 4346 1874-1947 -20 A 4254 1928-1947 -30 vt...... Burlington----- ...C 409 1884-1943 -29 Burlington----- ...A 335 1943-1944 -23 Va....... Gape Henry... 24 1874-1947 5 Lynchburg___ ...C 644 1874-1944 -7 Lynchburg___ Norfolk. ... ...Ar 951 91 1944-1947 1871-1947 7 2 Richmond....... ...c 180 1897-1947 -3 ...A 172 1929-1947. -12 ...A 1194 1935-1939 Wash... Eilensburg ...A 1731 1935-1939 18 46.1 . 44.3 19 46.7 33.7 -3. 37.3 3 39.0 -6 42.7 41.4 -2 40.9 38.7 . 41.2 37.7 40.1 : 1 37.5 22 67.4 55.0 19. 54.4 23 22 0 .6 '7 g6m7 . 26 49.2 . -26 28.2 - -21 33.4 9 50.3 ' 47.8 2' 47.9 46.8 ' '-9/ "51.1 '50.0 : . 5 48.5 ' 53.9 0 45.2 58.4- 19 19 H 20 11 29 66.8 63.7 - 13 55.6 ' 23 60.6 16 53.5 - 28 12 55.1 61.7 22 61.0 60.1 67.1 61.2 33 21 60.6 -15 -2 -17 36.3 40.0 38.3 31.5 32 26 23 --2 49.2 8 46.8 15 49.3 10 47.0 36.2 15 21 1 4.3 8.0 13.5 12.1 9.0 12.1 . 7.1 - 6.0 6.2 8.9 7.3 10.4 12.9 8.8 8.6 9.2 7.6 11.6 8.5 7.7 7.4 7.1 8.2 3.3 10 10 . -5 0 0 0 0 --5 0 15 10 10 -20 -20 10 0 0 15 --5 --10 20 30 20 15 10 10 20 20 15 20 -15 -10 10 15 7.3 3.9 13.6 7.6 11.0 11.6 9.0 7.6 20.6 12.1 10.5 8.0, 8.4 10.7 8.0 7.7 7.2 9.3 9.8 10.1 12.1 8.3 10.4 11.0 10.6 8.0 9.0 10.5 11.2 10.5 8.0 8.3 9.0 7.8 11.6 14.0 8.1 12.1 8.1 Heating Load 239 Table 1. Winter Climatic Conditioned(Continued). Col. 1 State' Col. 2 Station*1 Col. '3 Col. 4 Eleva- TTON* Period Record*1 FT Col. 5 Low. EST Temp. Rec* OHDd Col. 6 Aver age An-. NUAL Min. Temp. F Col. 7 Col. 8 Col. 9 Col. 10 Col. 1: Avg. Win ter' Temp.* Design Design DrtBulb Temp.' onTAC 97}% Wind Vel. at Design Temp*1 DbyBulb ' . Temp. ' IN Common Basis* . Use* Avg. Wind. Vel. 1 Dec. Jan.. Feb.1 F F Mph F.. Mpb Wash.. W. Va.. Wise... Wyo... North Head___ . O 199 1884-1947 Seattle ............ ..c 104 1890-1947 Seattle............... ..A 47. 1928-1947 Spokane............. ..C 2030 1881-1941 Spokane.,......... ..A 1974 1941-1947 Tacoma.............. . C 279 1897-1947 Tatoosh Is......... 110 1883-1947 Yakima............. ..c 1160 1938-1946 Yakima............. A Elkins................. . C 1066 1969 .1944-1947 1898-1944 Parkersburg----- ..C 685 1888-1947 Green Bay........ . c 598 1886-1947 La Croese.......... ..c 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 1927-1947 Cbevenne.......... -.0 6144 1873-1935 Cheyenne...... .-.A 6161 1935-1947 Lander............... ..C 5448 1891-1946 Lander............... ..A 5568'. 1946-1947 Rock Springs... ..A 6746 ; 1932-1942 'n 3 3 . -30 ' -7 7 7 -24 --4 -28 -27 -36 -43 r-28 : ,-29 : -25 i. -29 ; -38 ' -34 ' --40 -14 -33 24 46.4 20 46.3 45.1 -5 37.7 44.9 i . 45.4 39.8 -8 . -1 -18 -21 39.4 42.9 . 29.8 31.7 30.5 31.4 -12 33.4 -29.0 -18 , .33.6 '-12 . 30.0 30.1 ? 24 6.3 4 5.1 -17 6.9; -8 9.1 -6 11.9 -3 j' 111.1 -7; , 9.1 ' 20 15 -15 15 15 -5 -10 -10 -20 -25 -15 -15 --15 -18 16.1 9.8 `0.2 8.0 18.9 4.1 6.2 ' 7.1 10.5 9.3 "10.1 12.1 13.3 .3.9 Alta.. B. C:. Man.. N. B.. N. S.. Ont..;. P.E.I. Que... Sask.. Y. T.. Newf. Edmonton.......... Vancouver.......... Victoria............... Winnipeg............ Fredericton........ Yarmouth.......... London............... Ottawa___........... Port Arthur.-___ Toronto............... Charlottetown.. Montreal___ .-... Quebec.........,. i. Prince Albert... Dawson............... St. Johns............ 2219* 22 228 786* 164 136 912 294 644* 379 - 186 187 296 1414 1062 428 Up to 1943 Up to 1943 Up to 1943 Up to 1943 Up to 1943 -Up to 1943 Up to 1943 Up to 1943 Up.to 1943 Up to 1943 Up to 1943 Up to 1943 Up to 1943 Up to 1943 Up to 1943 Up to 1943 -67 .2 --2 -54 -35 -12 -27 -35 -40 -26 --27 -29 -34 -70 -68 -21 -^41 - 22.8 13 ' 42.6 19 44.0 -38 17.2 -25 > 27.5 . . 0* 34.8 -14 '32.6 -24 26.4 -29 .22.0 -11 32.7 --13. - 29.4 -18 23.9 -23' 24.5 -47 16.0 ' -54 1.9 . -5 31.5 . -40 i 7.6 10 :4.5 5 12.6 -35 10.1. . -20 9.1 -5 14.3 . -5 10.3 -20 ;8.4 -30 .8.0 -10 . 13.6 -10 9.8 ' -15 11.3 -20 13.3 -45 5.1 -45 .3.7 .-10 12 compiled from U. S. Weather Bureau Records for years indicated, and Canadian . data from Meteorological Service of Canada corrected to 1946. ' . - foltowSbyletter Q*itiom followed *>*lettCT A are airport stations. aU others are city office statione and are actuauLLil^ftfe r^FLi' The periods of record indicated apply.only to the lowest temperature ever recorded shown in OOX.5, and generally estendfroma summer month of the first year indicated through the spring months of the Ust year indicated. The periods marked by d terminated in December of the year indicated * Average of readings of one lowest temperature obtained for wb year. 1 For period October to April, inclusive. ' ' *" - th;**^8i10U44 8 Wg- ?Jy 10 ai{Port*> as these data for city stations are not available at 13 ***? *mpunm hourly outdoor temperature which has been equalled or ^ ^ur8_*m December, January and February for the period of record.' It is torural areas 1 m mOSt Casethe airport stations are outside of the city and these date would apply primarily thektS'pe9ri?ujSthown inSY'^ ^ CC^red ai temperat""the " loer then. fer reTt d>*nienipemture3 in use by A S.H.VJE. Member* es reported by Chepter Secretaries WheIJ th<e weTM "Ot available the design temperatures from an ACRMA puhiica- turn and venous other sources have been inserted. . K. throu^heFebnl948l0CitieS indicatd " ^ 11 were furnished by the U. S. Weather Bureau and corrected p-rep^red A-S.H.V.E. and U. S. Weather Bureau for annual weather data of city of Detroit indicates 6 as design temperature based on Dec. to March, inclusive. m Computed for.Reading by Karl Shelley and 0. F. Smith.* . . - 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 240 CHAPTER 11 1952 Guide 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 humidity of approximately 50 percent is required to produce an effective temperature of 68 ET when the dry-bulb temperatime is 72.5 F. However, .even where provision is made for artificial humidification,' the relative humidity is seldom maintained higher than 40 percent during the ex- H s'ST ' Heating Load 241 tremely cold weather, and. where no provision is made for humidification, the relative humidity may. be 20 percent or less. Consequently, in using , the figures fisted in Table .2,- consideration should be given to the actual relative humidity to be maintained, if provision is to be made for humidifi cation. If no humidification is to.be provided, the higher temperatures 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 a 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 Dby-Bolb Temperatures Usually Specified* Type op Building. .Deo F. -. Type op Building , Deg.F Schools-1 ". ' Assembly rooms............................................. Toilets and baths___.................................... Wardrobe and locker rooms............. 70-72 68-72 55-65 ` 70 65-68 65-70 60-65 . `75 ` Hospitals-- Private rooms......... _________ 70-72 Theaters--' Lounge rooms. ............................................... Hotels-- , ` Toilets' and service rooms........'.........;.... Homes.-________............... .............................. 68-72.. .68-72 \ 70 66 65-68 68 .70-73 Operating rooms........ __ ____ Wards..................... .v.\ .:.... Kitchens and laundries........ * 70-65 : `68 66 Public buildings...'......................v............. 68-72 .120 Steam baths.................................................... - 110 ' 70-80 .'50-60 Paint Shops. .. ............................ . .............. .80 _ * 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 Chapter 6.) - When relative humidity is not controlled separately, optimum'dry-bulb temperature for conifort *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 Levei. In making the actual heat loss compu 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 temperature at the proper level will be used. By air. temperature at the proper level is meant, in the case of walls, the air temperature at the mean height 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 from the tendency of the warmer or:.less-dense air-to rise. Amafiowance.for this fact should be made in calculating ceiling heat losses, particularly in the 242 CHAPTER 11 1952 Guide - 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 par ticularly 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* Breathing Betel Temperature (5 tt Above Floor) Height (Ft) 60 65 70 72 74 76 78 80 85 90 10 3.0 3.3 3.5 3.6 3.7 3.8 3.9 ` 4.0 4.3 4.5 11 3.6 3.9 4.2 4.3 4.4 4.6 3.7 4.8 5.1 5.4 12 4.2 4.6 4.9 5.0 5.2 5.3 5.5 5.6 6.0 6.3 13 4.8 5.2 5.6 5.8 5.9 6.1 6.2 6.4 6.8 7.2 14 6.4 5.9 6.3 6.5 6.7 6.8 7.0 7.2 7.7 8.1 15 6.0 6.6 .7.0 7.2 7.4 7.6 7.8 8.0 8.5 9.0 16 ` 6.1 6.6 7.1 7.3 7.5 7.7 7.9 8.1 8.6 9.1 17 6.2 6.7 7.2 7.4 7.6 7.8 8.0 8.2 8.7 9.2 18 6.3 6.8 7.3 7.5 7.7 7.9 8.1 8.3 8.8 9.3 ' 19 6.4 6.9 7.4 7.6 7.8 . 8.0 8.2 8.4 8.9 9.4 20 6.5 7.0 7.5 . 7.7 7.9 8.1 8.3 8.5 9.0 9.5 25 7.0 7.5 8.0 8.2 8.4 8.6 8:8 9.0 9.5 10.0 30 7.5 8.0 8.5 8.7 8.9 - 9.1 9.3 9.5 10.0 10.5 35 8.0 8.5 9.0 9.2 *9.4 9.6 9.8 10.0 10.5 11.0 40 8.5 9.0 9.5 9.7 9.9 10.1 10.3 10.6 11.0 11.6 45 9.0 9.5 10.0 10.2 10.4 10.6 10.8 11.0 11.5 12.0 50 9.5 10.0 10.5 10.7 10.9 11.1 11.3 11.6 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 Ho of one degree for each foot above 5 ft. Tnis table is generally applicable -to forced air types of heating systems. For direct radiation or gravity-warm 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 ys 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,* * * * 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 Heating Load 243 ceiling.heights under 10 ft), the breathing level to floor differential may also bemeglected, as the two are somewhat compensating, especially where both floor and ceiling losses are calculated for the same space.. In other cases, the 10 ft temperature differentials in Table 3 may be used in arriving at the floor heat loss, these differentials to be subtracted from,the .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: .. where _ AcUgTi +, t0(A,U, AwUj, + Agf/g) U ~ AM, + AM, + AM,, + AM, .. ( t, = attic temperature, Fahrenheit degrees. ti = inside temperature near top floor ceiling, Fahrenheit degrees. . <c = outside temperature, Fahrenheit degrees. . Ae = area of ceiling, square feet. A, = area of roof, square feet. .. .. Aw = area of net vertical attic wall.surface, square feet. A,, = area of attic glass, square feet. . V. = coefficient of transmission of ceiling, based on surface conductance of 2.20 (upper surface, see Chapter 9). 2.20 = reciprocal of one-half the air space ' resistance. U, = coefficient of transmission of roof, based on surface conductance of 2.20 (lower surface, see Chapter 9). (7w = coefficient of transmission of vertical wall surface. ' UB = coefficient of transmission of glass. ' Example 1. Calculate the temperature in an unheated attic, assuming the. follow ing conditions: tx = 70; t, = 10; Ac = 1000; A, = 1200; Aw ** 100; A, = 10; U, = 0.50; U, = 0.40; Uw = 0.30; U, = 1.13. . Solution:. Substituting these values in Equation 1:. . . (1000 X 0.40 X 70) + 10[(1200 X 0.50) + (100 X 0.30) + (10 X 1.13)] (1000 X 0.40) + (1200 X 0.50) + (100 X 0.30) + (10 X 1.13) 34,413 i. = ------ 33.1 F, 1041 Equation 1 neglects the effect of any interchange of air such as would take place through attic vents or louvers intended to preclude attic con densation. However, according to tests,8 such venting of attics by means of small louvers or other small openings does not appreciably reduce the attic temperature and may be neglected without serious error. -Neither does this equation take into consideration such factors as heat exchange between chimney and attic or solar radiation to and from the roof. Because of these latter effects, actual attic temperatures are fre quently higher than the calculated values using Equation 1. The attic 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 assump tion will generally be considerably less than if the roof were neglected (as is sometimes the practice) and the attic temperature assumed to be the same 244 CHAPTER 11 1952 Guide as the outside temperature. When relatively large louvers are installed, as is customary in the southern states, the attic temperature is often assumed as the average between inside and outside. For a shorter, approximate method of calculating heat losses through 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. _ i(AjVi + AjUt + A,U, + etc.) + UAJJ* + AbUb + ACU, + etc.). " AiUi + AMi + A,Vi + etc. + A.tT. +. AbUb + ACU, + etc. ' where ; . i,, = temperature in unheated space, Fahrenheit degrees. t = inside design temperature of heated room, Fahrenheit degrees. .. to = outside design temperature, Fahrenheit degrees. A,, At, As, etc. = areas of surface of unheated space adjacent to heated space, square feet. A., Ab, A,,, etc. = areas of surface of unheated space exposed to outside, square feet. Ui, Ut, Ut, etc. = coefficients of transmission of surfaces of Ai, At, Aa, etc.. t/., Ut, Uc, etc. = coefficients of transmission of surfaces A, Ab, Ac, etc. . Example 2: Calculate the temperature in an unheated space adjacent to a heated room having surface areas (A,, At, and A,) in contact therewith of 100, 120, and 140 sq ft and coefficients (Uh U,, and U,) of 0.15,0.20, and 0.25, respectively. The surface areas 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 6ixth surface is on the ground and is neglected in this example. Assume t = 70 and U = -- 10. Solution: Substituting in Equation 2: 70[(100 X 0.15) + (120 X 0:20) + (140 X 0.25)] + -10[(100 X 0.10) + (140 X 0.30)1 U = (100 X 0.15) + (120 X 0.20) + (140 X 0.25) + (100 X 0.10) + (140 X 0.30) 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 temperatures under, the floors generally being higher than those adjacent to walls. Factors affecting these temperatures will be discussed. i Heating Load 245 Temperatures Under Basement Floors ,, The temperature of the ground under basement floors9 is affected by heat , sources within the basement and is not influenced by atmospheric 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 34. 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 Grade Heat Losses eob Basement Walls and Floors . Ground Water ' Temperature* Lossb .' Basement'Floor . Btu/Sq Ft Btu/Sq Ft . -. 40 ': 1 50 60 3.0 2.0 1.0 . ? Sec Fig. 3, Chapter 34. . ... ` ` b Based on basement temperature of 70 F and U of 0.10. - 6.0 . 4.0 2.0 , . - winter; the'gfound temperatures near the surface-will be higher than when* 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 ment walls in contact with the soil is only 0.10, any reasonable, assumed ground temperature will not materially affect the calculated heat loss. BASEMENT TEMPERATURES AND HEAT LOSS The allowance to be made for basement heat loss depends on whether the basement is to be heated or not. . '. If the basement is healed to a specified temperature, the heat loss should be calculated in the usual manner, based on the proper wall and floor co efficients (see Chapter 9) and the outside air and ground temperatures. Heat loss through windows and walls above grade should be based on out 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 ground, temperature. . . . . ; -. The heat loss values for below grade,basement walls and floors given in Table 4 are sufficiently precise for general practice. . - If a basement is completely below grade and is not heated, the tem perature in the basement normally will range between that in the rooms, above and the ground temperature. Basement windows will, of course, lower the basement temperature when it is cold outside, and heat given off by the.heating plant will increase the basement temperature. In any case, the exact basement temperature is indeterminate if the basement is not, heated. In general, it is found that the transient heat from the heating 246 . CHAPTER 11 1952 Guide plant warms the air near the basement ceiling sufficiently to make it un 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. - FLOOR HEAT LOSS IN BASEMENTLESS HOUSES ' Two types of concrete floors are in common use in basementless houses: (a) the Boor not heated but relying for warmth on radiation received from walls, ceiling, etc.; and (b) the floor containing heating pipes or ducts and constituting a radiant slab for heating or partially heating the house. ` For type (a) the floor heat loss, economically considered, is of minor importance since it comprises generally about 10 percent of the total heat, loss of the house. From the comfort standpoint, however, it may be most important, since houses with cold floors are not successfully heated. In this 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 ceiling panel heating system or other system capable of warming the floor uniformly by radiation. Data are meager, but the results of some experiments'0-11 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 loss can be estimated by means of the formula: Hr = FP (t - O (3) where . Hp = 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 0.81 for a floor with no edge insulation to 0.55 for a floor with edge in sulation). ' t = inside air temperature, Fahrenheit. to = outside air temperature, Fahrenheit. . In most instances the values given in Fig. 2 for edge loss are of sufficient precision for use.'* The insulation shown extending under.the floor (about 2 ft) can also be located along the foundation wall with equal effectiveness if the insulation extends 18 in. to 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 insulated at the edge with 1 in. of insulation, and the house is located in zone B (outside design temperature = --10 F). Solution: From Fig. 2 the heat loss per foot of exposed edge is 55 Btu per hr. The length of exposed edge is 12 ft + 15 ft = 27 ft, and the total edge loss is 27 x 55 = 1485 Btu per hr. Floors of type (b), consisting of concrete slabs placed on the ground, and containing heating pipes or ducts, are now in use in many small dwelling houses. The heat loss downward or through the ground from such floors . Heating Load 247 is called the reverse loss. Authoritative data for computing or estimating the magnitude of reverse losses are lacking, it is customary for designers to allow a percentage (often in the range from 10 to 20 percent) of the house ` heat loss to cover the reverse heat loss from such a floor. There is some indication that it may be possible to use Equation 3 to estimate the reverse loss by substituting for t the temperature of the heating medium. . The desirability of edge insulation is apparent, but standards of practice have not been established: An inch of waterproof material is the minimum thickness of edge insulation that should be used, and greater thicknesses are recommended.12 Such a floor usually is placed above a cinder or gravel - fill four or more inches thick, both to insulate the floor from the earth and to retard the rise of ground water by capillarity. Obviously, it is important that such floors be laid several inches above grade, and that effective sub soil drainage be provided to avoid slabs soaked by rain or melting snow, and consequent excessive heat loss. ." Tmperatur Zoo* for Design Purposes Rtconmendxi T Edg* rEdg* . *Ne Edg* *n*fewbaotmomwKhA ' ` J f Tir --r~*~y "V Fio. 2. Heat Loss per Foot of Exposed Edge fob Concrete Floors at or Near Grade Level.11 . TRANSMISSION HEAT LOSS The basic formula for the loss of heat by transmission through any surface is given in Equation 4: H, = ATJ (t - f,,) . (4) where Ht = heat loss transmitted through the wall, roof, ceiling, floor, or glass, Btu per hour. A -- area of wall, glass, roof, ceiling, floor, or other exposed surface, square feet. XJ = coefficient of transmission, air to air, Btu per (hour) (square foot) (Fahr enheit degree temperature difference) (Chapter 9). t = inside temperature near surface involved (this may not necessarily be.the so-called breathing line temperature), Fahrenheit degrees. , to = 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 f is 70 F and the outside temperature L, 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)] = 6000 Btu per hour. 248 CHAPTER 11 1952 Guide Transmission Loss 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 -- i0) and the proper value of U: . - s: Flat .roofs. Select the coefficient of transmission of the ceiling and roof from . : Tables 15 or 16, Chapter 9, or u?e 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. ... ... - ,1 2. By estimating the attic temperature (based on the inBide and. outside design - temperatures) by means of Equation 1, and substituting-.for tQ.in Equation-4, the value of /thus obtained, together with the ceiling area A and the ceiling coefficient U. This applies to pitched roofs. In the case of flat roofs it is not necessary to calculate the attic temperatures, as the ceiling-roof heat loss can be determined as suggested in paragraph la. INFILTRATION HEAT LOSS ; The infiltration heat loss includes (1) the sensible heat loss or the heat required to wann the outside air entering by infiltration, and (2) the latent heat loss or the heat equivalent of any moisture which must be added. . Sensible Heat Loss . The formula for the heat required to warm the outside air which enters a room by infiltration to the temperature of the room, is given in Equation 5: ` : ' ' ' ' H. = 0.240 Qd (t - <,,) (5) where . H, = heat required to raise temperature of air leaking into building from t,, to t, Btu per hour. 0.240 = specific heat of air. . Q = volume of outside air entering building, cubic feet per hour (see Chapter 10). ' - d = density of air at temperature tOI pounds per cubic foot. . It is sufficiently accurate to use d = 0.075 in which case Equation 5 reduces to - H. = 0.018 Q (.1 - t0) . (5a) The volume Q of outside air entering per hour depends, on the wind velocity and direction, the width of crack or size of openings, the type of openings and other factors, as explained in Chapter 10. Where the crack method is used for estimating leakage, it is more convenient to express the air leakage heat loss in terms of the crack length: ' ' H, = BL(t- t,,) ' (5b) where ' B = air leakage per (hour) (foot of crack) (Chapter 10) for the wind velocity and type of windows or door crack involved, multiplied by 0.018. L = length-of window or door crack to be taken into consideration, feet. Heating Load 249 Example 5: 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 zero, respectively. . Solution: According to Table 2, Chapter 10, the air leakage through a window of this type (based on A 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)-+ (3 X 3), or 19 ft; t = 70 and t0 = 0. Substituting in Equation 5b, . Em -- 0.70 X .19 X (70 -- 0) = 931 Btu per hour. . .. . Crack Length to be Used for Computations . . . For designers who prefer to use the crack method, the basis of calculation is as follows: The amount of crack used for computing the infiltration heat loss should be not less 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 on the leeward side. Therefore, take one-half the total crack for computing each side and end of the building. In a room with one exposed wall, take all the crack; with two exposed walls, take the wall having the most crack; and with three or four exposed walls, take the wall having the most crack; but in no case take less than half the total crack. . , In small residences the total infiltration loss of the house is generally considered to be equal to the sum of thd. infiltration losses 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 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 10 indicates air changes commonly used, but should be taken only as a guide.' ' ...... . ' : - When calculating infiltration losses by the air change, method, Equation 5a may be used by substituting for Q the volume of the room multiplied by the nimiber of air changes obtained from Table 4, Chapter 10. For further discussion of the method see section on Air Change Method in Chapter 10. - .. 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 (W, - W0) h,, . - ... , - ' (6) .- Hi = heat required to increase moisture content of air leaking into building from m0 to Btu per hour. . Q = volume of outside air entering building, cubic feet per hour. i 250 CHAPTER 11 19S2 Guide . d = density of air at temperature l-,, pounds per cubic foot. . - W, = vapor density of inside air, pounds per pound of dry air. . W,, -- vapor, density of outside air, pounds per pound of dry air. his = latent heat of vapor at to., Btu per pound. ' . . " . If the latent heat of vapor h/,, is assumed to be 1060 Btu per lb, Equa tion 6 reduces to: . .. Hi = 79.5 Q (Wi - wj (6a) Equations 5a, 5b and 6a may also be used for determining the sensible . and latent heat gains due to infiltration, in cooling,load computations. ; SELECTION OF WIND VELOCITIES . .The effect of wind on the heating requirements of any building should be given consideration for two reasons: .. ; .... .1. Wind movement, increases the heat transmission of walls, glass, and roof, 'affecting poor Walls to a much greater extent'than good'walls. . : 2. Wind increases materially the infiltration of cold air through the cracks around doors and windows, and even though the building materials themselves (see Tables 1 ;and 2, Chapter 10). . . .. ' . 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 with1 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 :for 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 average velocity of .winds occurring at temperatures equalled or exceeded 97? percent of.the winter period for each locality, this, value should be the basis for estimating infiltration losses. When using the air change method it will, not be necessary to consider the wind velocities. Designers employing the crack method generally use values corresponding to a lfi-mile wind. Due to the small effect of the wind velocity on the transmission, coefficient, the values in Chapter 9,: based oil a 15-mile wind may be iised with sufficient accuracy for all ordinary conditions. :1 . , Exposure Factors Many designers use empirical exposure factors to increase the calculated heat loss of rooms, or spaces on the tide or sides of the building exposed to the prevailing winds. However, the use of exposure factors is .unneces sary when the Guide method of calculating heat losses is used. Therefore, exposure factors may be regarded as factors of safety 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 of multi-story buildings. Tall buildings may have severe infiltration heat losses, induced by their stack effect (see Chapter 10), 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 to Heating Load 2511: a large extent be a matter of experience and judgment of the designer, since there are at present no authentic test data available from which rules-.; could be developed for the many conditions ^encountered in practice, '~i AUXILIARY HEAT SOURCES :: The heat supplied by persons, lights, motors and machinery alwaysj should be ascertained in the case of-theaters, assembly halls; and industrial^ 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. have; a marked effect on.the operation and control of the system:. -In general,,:, where audiences: are present, the heating system must have sufficient capacity to bring the building to the stipulated inside temperature before the audience arrives. In..industrial plants, quite a different condition exists, and heat sources, if always available during occupancy, may be substituted for a portion of the heating installation. In no case should the Table 5. Heat Equivalents of Vabious :Sookces* 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 12, Table 29. actual heating installation (exclusive: of heat sources) be reduced below that required to maintain at least 40 F in the building. Electric Motors and Machinery . 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 to the machinery from the outside, then only the heat equivalent of the brake horsepower supplied is used. In some mills this is the chief source of heating, and it is frequently sufficient to overheat the building even. in zero weather, thus requiring cooling: by ventilation the year 'round. Table 5 shows the heat output equivalent 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 28, Chapter 12. For appliances see Table 29, Chapter 12. 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.13 . 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 252:: CHAPTER 11 1952 Guide Fig. 3. Elevations and Floor Plans of Residence Heating Load 253 Table 6. Heat Loss Calculation Sheet fob Uninsulated Residence ... (Fig. 3) . .... .... , ..... .. .. A B - 1 C ! b E' F 'JL ' o . Room oa' Space - Past or Stbuctubeob Infiltration Aib Changes Net Abea ob Aib Volume . CIENT Dipt.* Heat Lobs (Btu per . hour) _ ' .Totals hour) -. Bedroom A ' and Closet Bedroom B and Closet Walls - . , . . 238 sq ft.: 0.28 . 80 5330. : Glass 40 sq ft - 0.45 . .80 . .. 1440 Ceiling . .. , . 262 so ft 0.69 39.8*. . 6910 Infiltration $0* ' ' ` 1510cfhb;- 0.018 80 * 2180 Walls . Glass . Ceiling Infiltration (H)* l&6sqft 0.28 . -80 . ' 3490 ' ; .40 eq ft 0.45 . 80 ,A 170 salt 0.69 V 39.8* - 1440 . .4660 1020 cfhb 0.018 sa 1470;: .. * "16,850 . % 11,060. Bedroom C and Closet Bedroom D and Closet Walls ;. Glass. -. . Ceiling ' Infiltration (H)* : . .114 sq ft--: 0.28 27 eq ft . 0.45 129 so ft 0.69 874 dnb ` 0:018 Walls . Glass ' Ceiling Floor over garage Infiltration 04)* ' ' * - 118 sq ft. . . 20 sq ft' 110 sq ft ' UO'eqJt 660cfhb 6.28 ' 0.45 0.69 0.25... 0.018 80.. 80 . 39.8^ 80 .2560 970 . , 3540. ' = 1260 " i . -x 8.330 80. .. 80 . 39.ff* 35 80 , 2650 - . ` 720 -3020 960*' 950 : - - ' .. J 8.300 Bathroom 1 Walls' Glass Ceili-ntr InfilNation (1)* ' 30 sq ft ' 0i.28 *80 : ' 670 14 sq ft 0.45 ' 80 - - 500 <- 65 sq.ft 0.69 39.8d 1510 440cfhb 0.018 80 630 3,310 Bathroom 2 " Walls ` ' Glass Celling '=- . Floor oyer 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 ' 1640 80 . 320 . 960 ... 35 310* ` 80 --. -------400 . -- Jj; .1. -3,630 - Living Room Dining Room Walls ^ . Walls (adfoinin? garage) Glass Floor ' ,, Infiltration (lH)h ~ Walls ;= Glass (doors) Glass (windows) Floor , Infiltration (1VS)` ; r- 267 sq ft 94 sq ft . 50sq-ft 294 sq:ft i 3745cfhb 0.28. 0.39* 0.45 0.018 166 sq ft 35 sq' ft 20 sq ft 188 sq ft ' 2140cfnb - 0.28 0.85 0.45 0.018 80 35 80 80 80 80 80 80 5980 1280* 1800 6400 3720 2380 720 3080 A . ,,. -i! 14,460 i _. ... 9,900 Kitchen and Entrance to Garage Walls - Walls (adjoining garage) Glass - ."* Door ' - Floor . Infiltration (1H)1 ;/ . . - 96 sq ft 51 sq ft 18 sq ft 17 sq ft 125 sq ft 1595cmb 0.28. 0.39* 0.45 0.51 80 85 80-: > 35 0.018 80 - 2150 700* 650 300 r 2300. ... 6,100 Lavette and Vestibule Walls '` Walls (adjoining garage) Glass Door ' Floor . -Infiltration (lH)b . 82 sq ft 85 sq ft 9 sq ft -. - 19 sq ft 30 sq.ft 383cf&b . 0.28. 0.39' 0.45 0.51 ,0.018 80 35 80 80 80 1840 1160* 320 780 r 550 x- 4,650 Entrance Hall Walls Door . Ceiling1, InfiltiationCS)1.' 39 sq ft 0.28 80 21 sq ft 0.38 80 . 87 salt 0.69 sg.ff* ' mocfhb 0.018 80 870 640 2390 1600 5,500 Garage Walls . Glass Doors- Infiltration 0H)0 Floor - Gain adjoining toozds 167 sq ft 0.28 45 . 53 sq ft 1.13 45 0.51 . 45 2360 0.018 .45 29 ft* * 0.81 45 2110 2700 1010 1910 1060 -4410* r- 4,380 Recreation Roomg Walls Glass - Floor . Infiltration 0 )" 220 eq ft 0.10 38 . 8 sq ft ' 1.13 .80 287 sq ft 0.10 20 2010 cfhr 0.018 80 . 840 720 57Q 2890 6,020 TOTAL . 100,500 . Jfta :254 CEUPTER 11 1952 Guide . ... ;N.OTES FOB TaBL 6., . . The inside-outside temperature difference ia 70*- (--10) or 80 F except where otherwise noted. 1 b Volume of infiltration, cfh = (no. air changes) x (floor or ceiling area) x (ceiling height). ... e From Equation.Sa. . .. . ' ....... - ......................, d The ceiling beat losses are calculated by estimating the attic temperature andthen calculating the loss through theoeuing using the'proper temperature difference. This unheated attic is not ventilated during winter The attic temperature is estimated from Equation l to be 30.3 F when the outside tem perature ia --10-F- and room temperature is 70 F. The temperature difference is then 70--30.2 or-39.8 deg. Jfor the residence, attic temperature becomes 4.6 F and temperature difference 70--4.6 = 63.4 deg. Temperature in garage assumed to be 35 F. . f Coefficient for wall adjoining garage calculated on basis of metal lath and plaster op both aidee of studs (U - 0.39). .- - '.................................................................... . .............. c One half of value from Table 4, Chapter 10, for storm windows or weatberetripping. . b Exposed on two sides, weatherstripped. windows offset by fire-place. Use \\i. * 1 Window on one side treatherstripped but double-doora are hard to dose tightly. Hence, conservative value of 1V$. -: ............................ 1 Ammmltig kitchen vent, door to vestibule usually open, allow full table value of l)i. ................ 1 - k One-half value in Table 4, Chapter 10, increased to 1M by nearby outside door in vestibule. ** 1 Full value in Table 4, Chapter 10, to allow for frequent opening of outside door. . - . " Two sides exposed, large doors but large volume. Use value 1J4 as given in Table 4, Chapter 10. -B Two unweaiherstripped windows in protected location, but fireplace, indicate 1 change;' P Heat losses from these rooms into garage are beat gains for garage. .. U Neglect heat to basement, as losses from boiler, piping, etc., will probably keep basement near, f not above, 70 F. ' - Upstairs hall ceiling figured with downstairs. Heat should be provided downstairs for both;. - * Linear feet of exposed edge. - )Table 7. Summary .op Heat Losses of Uninsulated Residence (fitu Per Hour Room ob Space - 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 Totals6 Percentage^ " Walls 6330 3490 2560 2660 670 1640 7260 3720 2850 3000 870 --1030* 840 33.850 83.850 38.4 Ceiling and Roar 6910 4660 3540. . 3020 1510 960 2390. --1270b. 21,720 21,720. 24.6 Floob Glass and Door InfilTBATION 1440 . 2180 1440 1470 970 1260 .960 720 950 500 630 310 320 400 . . . 1800' 5400 . 3100 3080 950 2300 1100 550 640 1600 1060 .3710 , 1910 . 570 - . . 720 2890 2,900 2,900 3.3 17,410 17,410 19.7 24,620 12,310 14.0 Totals 15,860 11,060 8,330 8.300 3,310 3,630 . 14.460. . 9.900 6,100 4.650 5,500 4,380 5.020 100,500 88,190 100.0 Wall heat lose of S1I0 Btuh minus Wall heat gains of 1280,700 and 1180 Btuh. b Heat gains of 960 and 810 Btuh. Based on H computed infiltration. Based on operating totals. )Table 8. Summaby of Heat Losses of Insulated Residence (Ptu Per Hour - Room ob Space Bedroom A '' Bedroom B . .Bedroom C . Bedroom D Bathroom 1 'Bathroom 2 Living Room Dtning Room Kitchen fovette . . Entrance Hall Garage . Recreation Design Totals. Operating Totals* Percentages* . . Walls ' Ceiling . and Roof 2480 1620 1190 1230 310 760 3370 1730 1320 1390 410 ' -470* 840 2460 1660 1260 2080 540 . 250 850. --910 16,180 16.180 29.1 7,190 7,190 12.9 Floob - 690 220 1060 570 2,540 2,540 4.6 Glass and Doob InvtlTBATION 1440 1440 970 ' `1 720 500 320 1800 8100 ' 950 1100 640 3710 720 2180 1470 1260 950 630 400 5400 3080 2300 550 1600 1910 2890 17,410 17,410 31.3 24,620 12.310 22.1 Totals 8,560 6.190 4,680 4.670 . 1,980" 1,950 10,570 7,910 4,570 3,040 3.500 5.300 5.020 67.940 55.630 100.0 * Wall heat loss of 980 Btuh minus wall heat gains of 690,320 and 540 Btuh. b Heat gains 690 and 280 Btuh. c on H computed infiltration. 0 Based on operating totals. Heating Load 255 biiildings 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/chrirches, auditoriuriis and other interriuttently heated buildings, additional capacity should be provided. .. , . : . .. . .. RESIDENCE HEAT LOSS PROBLEMS Example 6: Calculate the heat Iosb of the residence shown in Fig. 3 located in the vicinity of Chicago. From Table 1, design outdoor conditions are --10 F and 12 mph wind velocity. Inside temperature from Table 2 is assumed to be 70 F. The attic is unheated. Assume ground temperature to be'50 F (see Fig. 3, Chapter 34) under basement and garage floors and 32 F adjoining basement walls. Estimate infiltration losses by the air change method.- No wall, ceiling or roof insulation is to be con sidered in this problem, but all first and second floor windows, except in the garage, are to have storm sash. The building is constructed as follows (heat transmission coefficients U are parentheses): . .: :- . . . . Walls: Brick veneer, building paper, wood sheathing, studding, metal lath and plaster (0.28). Walls of dormer over garage,'same except wood siding in place of brick veneer (0.26). ?: .. . Attic Walls: Brick veneer, building paper,1 wood sheathing on studding-(0.42). Basement Walls: 10 in. concrete (0.10). " Roof: Asphalt shingles on wood sheathing on rafters (0.53). :\ Ceiling (Second floor): 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 6, and a summary of the results in Table 7. The values in column F of Table 6 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 6 for further explanation of data. Attention is called to the summary of heat losses (Table 7) for the uninsulated resi dence. As storm windows are used in this instance the glass 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 wail, ceiling and floor transmission losses comprise 66.2 percent of the total. . Example 7: Calculate the heat loss of residence shown in Fig. 3 based on the same conditions as in Example 6 but having construction improved or insulated to obtain coefficients as follows: . Walls, 0.13; Walls of Dormer over Garage, 0.12; Attic Walls, 0.28; Walls Adjoining Garage, 0.18; Basement Walls (Recreation Room), 0.10. Roof, 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 8. REFERENCES 1 ACRMA Application Engineering Standards for Air Conditioning for Com fort, (1947), Air Conditioning and Refrigerating Machinery Association, Inc., pages 4 to 7. 256 CHAPTER 11 1952 Guide ~ * An Analysis of Winter Temperatures for One Hundred and Twenty Cities, by Clark.M. Humphreys (Carnegie lnslitute of Technology Bulletin 1939). . Investigation Of Oil-Fired Forced Air Furnace Systems in the Research Resi dence, by A. P. Katz and S. Konz<f (.University of Illinois Engineering Experiment Station Bulletin No:`818). . > 4 Performance of a Hot-Water Heating System in the I=B = R Research Home at the University of Illinois, by A. P. Kratz, W. S. Harris, M. K. Fahnestock, and R. J. Martin (University of Illinois Engineering Experiment Station Bulletin No. 349). '* A, Study of Radiant Baseboard Heating in the I=B = R Research Home, by A. P. Kratz and W. S. Harris {Engineering Experiment Station Bulletin No, 358). ? Performance of a One-Pipe Steam'System in the I=B=R Research Home, by \V. s, Harris (University of Illinois Engineering Experiment Station Bulletin N o. 383)' / 7 A.S.H.V.E. Research Report No. 1011--Tests of Three Heating Systems inan Industrial Type of. Building, by G. L. Larson, X). W. Nelson, and John James;. (A.KH,V.E. Transactions, Vol. 41, 1935, p.-185). - ... ' * 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 Bulletin .No,17>.. ... -. . 9 A:S.H.V.E. Research; Report 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. Transactions; Vol. 48, 1942, p: 369). 10 Measurements of Heat Losses from Slab Floor, by R. S. Dill, W. G., Robinson and H. E. Robinson (U,S. Department of .Commerce, National Bureau of Sgandards, Building Materials and Structures Report BMS 103).. '. .' 11 Temperature and Heat. Loss Characteristics of Concrete Floors Laid on the Ground, by H.D. Bareither, A. N. Flemming and B. E, Alberty (University ofIllinois, Small Homeh Council Technical Report). -" , '[ 11 Concrete Floors fbr Basementless Houses (University of Illinois, Small Homes Council Circular No. F.4.3). ' ' 19 Heat Requirement Tables for Intermittently Heated Buildings (Engineering Experiment Station Bulletin No. 60, A. arid M. College of. Tezaa,.College Station, Texas) contains a .set of tables.applicable.to.either intermittent heating or cooling. Further'information`may be'found'in' a p'aper, A Method of Compiling Tables for Intermittent Heating, by, Elmer G. Smith (A.S.H.V.E: Journal, Section,.Heating, Piping and Air Conditioning, June 1942,:p. 386). '1 CHAPTER 12 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 and Floors; Load from Outside Air,i_. Ventilation and. Infiltration;:Effect of Outside, Mr-on Load; Heat Sources Within Conditioned Space; Moisture Transfer Heat Load; Miscellaneous Heat Loads; Required Air Quantity Through Conditioning Equipment; Minimum Entering .... . Air Temperature; Example Cooling Load Calculation ' '' : -" THE variables affecting cooling-load calculations aj"e numerous, often difficult to define precisely, and always intricately inter-relatied. 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. - 7: - 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.preinium 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. r The calculation procedures presented in this chapter deal with the; vari ous instantaneous,rates of heat, gain, both sensible and latentj in a condi tioned space. There may be an appreciable difference .between the net instantaneousrate of heat gain and the (6tal cooling load at any instant. This difference is caused by the storage and subsequent .release of heatby the structure and its contents.' This thermal-storage effect may be quite im portant in determining ah 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 and data presented for calculating individual components of the net rate of instantaneous heat gainl ' -: ' :; Solar healing calculations involve the same principles as codling load calculations.. Many, of the data oil ,solar radiation given in this chapter can be used in calculations for solar.heating. '......... .; COOLING LOAD; CALCULATIONS Summer cooling load calculations, whether for industrial or comfort . applications, require consideration of the following factors: A. Design Conditions: (1) indoor conditions; (2) outdoor conditions; (3) venti lation rate. - ' ', B. Instantaneous Heat Load, Sensible arid Latent: (1) load from solar radiation, 257 258 CHAPTER 12 1952 Guide 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 due to heat sources within the conditioned space such as people, lights, power equipment, and appliances; (5) load due to moisture transfer through permeable building materials; (6) miscellaneous heat sources. 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. 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 Commebcial Design Room'Conditions fob Summer Average Peak Load in Comfort Air Conditioning* Type of Installation Dry-Bulb Temp Deluxe Application............. Normal Application_______ 75 to 40 min Occupancy.___ 78 80 82 Wbt-Uulb Temp* Relative Humidity Per Cent 65 50 67 51 68 49 Grains Per Lb* Effective . Temp* 72.7 78.5 80.0 72.2 74.0 75.3 . * Values in Table 1 are for peak lead conditions. It is general practice to operate a system at approxi mately 76 F and 50 percent relative humidity at other than peak load. - . b Fsychrometric data for standard barometric pressure. . . . Fig. 10, Chapter 6, air movement 15 to 25 fpm. 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 de sign conditions for which summer air-conditioning equipment is selected, should not exceed a temperature of 80 F or a relative humidity of 50 per cent for the average job in the United States. If these conditions are exceeded, complaints of discomfort may be expected, especially with continu ous occupancy. For veiy brief occupancy only, a slightly higher peak load design temperature may be employed. In regard to the lower limit of humidity, complaints are not encountered for store installations' oper ated down to 35 percent relative humidity or, for office jobs, somewhat lower. These observations apply to normal commercial practice in this country only; for extremes, such as tropical or very hot regions, it is regarded as more practicable to design for a peak-load outdoor-indoor temperature difference of about 15 to 20 F. Table 1 offers typical design conditions for average requirements en countered. The deluxe figures would also apply in general for localities having a summer outdoor design temperature of 90 F or less; and the 15 to 40 min occupancy values, or even somewhat higher dry-bulb tem- Cooling Load 259 peratures, would indicate acceptable'conditions for very hot localities.Table 1 is to be used with goodjudgment, for there is no universal rule which may be applied to indoor design conditions. ", . ' `- i 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 this Table 2. Classification Materials, Location or Process Temperature F Relative Humidity Employee Efficiency Storage Prior to Manufacturing Manufacturing Process ' Research and Development General Machine Shop Work Drafting Rooms............... Offices'....................... ........ Rough Caatings........................ Ceramic Materials.................... Pharmaceutical Powders........ Sugar................................... Paper................................'' Electrical Goods....... .!!! Flour................................... * ` `' Rubber.................... .....\.f* Grains.............................. Hardened Aluminum Alloys. Machine Tool Oil Cooling................... Precision Parts Honing Machinery.. Ceramic Molding............................... . Manufacturing of Electrical Wiring.. Assembly Line............................. ........ Gage Rooms................................... ....... Instrument Calibration. Match Manufacturing.......................... Paper Testing Laboratory.................. Textile Testing Laboratory....... ........ Special Process Temperature Boxes. Chemical Laboratories....................... Fibres and Plastics............................... Drafting.___ .................................... Temperature Shock Tests;................. 78-80 . 78-80 78-80 60-80 70-80 80 75-80 . 60-80 60-75 60-75 - 60 0 to -30 70-00 75-80 . 80 60-80 65-80 78 68 72-74 60-80 70 -100 to +170 - .78 . 70-75 78-80 -80 to +150 .50 50 50 50 50 15-35 35 35 . 35-60 55-65 40-60 30-45 40-55 . 60 35-50 5400-50 50-56 50 55-65 65 50 50-65 45-50 Cleveland fn?m l^e ariic!e>-!*`I^oor C*imate and Refrigeration Engxruenng, Vol. 40, No. 27, July 3, 1947, p. " for Post-War Industry," by E. K. TTg1m comfort and .efficiency of the workers. No generally-applicable specifica-tions are possible, as each job has its own special requirements. Table 2 offers illustrative general information. 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-toindoor 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 3 for various locations in the United w 260 CHAPTER 12 1952 Guide " 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 3, due considera tion must be given to elevation. ' . Column 6 of Table 3 indicates the design dry-bulb temperature suggested; by the A.S.H.V.E. Technical Advisory Committee on Weather Design Conditions. This temperature is the maximum hourly, outdoor tempera ture which has been equalled or exceeded 2 percent of the total hours of. June, July, August and September for the period of record,, in this case, the 5-year period 1935-1939, and should not be confused with the period of . record given in Column 4 which, applies only to highest temperature ever recorded. Since all of these data (Column 4) are based on airport records, they are not necessarily applicable to cities. , The data given in Columns 7 and 8 were obtained from local A.S.H.V.E. Chapter Secretaries, and represent the design temperatures in local use. Where such information was not available, it was taken from a publication of the A.C.R.M.A.1 and frond various other sources. The Technical Advisory Committee on Weather Design Conditions has suggested that wet-bulb design temperature be taken as that wet-bulb temperature which has' been equalled or exceeded 5 percent of the hours during months of the period of record. While not available for the 1951 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 aver age of the daily minimum temperatures. This range is highest in semiarid or desert regions and at high elevations, and lowest near the oceans or very large lakes. The daily range of temperature (Fahrenheit de grees) in July for the principal areas of the United States can be ap . proximated from the following tabulation: East Sea Shore.. :........12 to 18 Gulf Sea Shore............. 12 to 18 Great Lakes Shore.... 18 to 21 West Sea Shore........ 15 to 20 East of Mississippi River.............................. 19 to 24 Mississippi River to Rocky Mountains... .24 to 33 Rocky Mountain Area.................................... 33 to 42 West Coastal States........................................ 20 to 36 Ventilation Rate , The introduction of outside air is necessary for the ventilation of condi tioned spaces. Chapter 6 suggests minimum outdoor-air requirements for representative applications; but it is to be emphasized that minimum re-; quirements are not necessarily adequate requirements for all psychological attitudes and physiological responses. Local codes and ordinances frequently specify ventilation requirements, for public places and for industrial installations. Recommended and minimum Ventilation rates for the most cpmmon. Cooling Load 261 Table 3. Summer Climatic Conditions Suggested Design Wei-Biilb and Dry-Bulk Temperatures Col. 1 State Col. 2 Station? Col. 3 Eleva tion* Ft Col. 4 . Period Col. 5 ' Col. 6 Col. 7 Highest Temp. Design Design Dry-Bulb Dry-Bulb Temp, on Temp, in ' Recorded4l T.A.C. 2*7j Common F F QF Design Wet-Bulb Temp, in Common Use* Ayerage Summer ! Wind Velocity* F ; MPH Ala.'.... AnnintoD . .. CO Birmingham.. ..CO Birmingham.. AP Mobile............ CO Mobile............. AP Montgomery. ..CO Montgomery.. ..AP Ariz.... Flagstaff......... CO Kingman....... AP , Phoenix_____ . CO Phoenix....... ..AP Tucson............ AP : Winslow.......... CO Winslow__ ... ..AP Yuma............. CO Art.... Fort Smith;.. CO Fort Smith:.. AP . Little Rock... CO Little Rock... ..AP Calif... Bakersfield___ AP Burbank......... AP Daggett___... AP Eureka............ .CO Fresno............. .CO Fresno............. AP Los Angeles... CO Oakland......... AP Red Bluff..... <X> -Red Bluff..... AP Redding......... .AP : Sacramento... CO (Sacramento... AP = San Diego....... CO San Diego.... AP San Francisco. CO San Jose......... CO Williams......... AP Colo....'. Denver........... <X> Denver............ .AP Durango......... CO Grand Junction.CO Pueblo............ CO Pueblo............ AP Conn,, . Hartford......... CO Hartford......... AP New Haven... CO New Haven... AP D. C. .. Washington... (X) Washington... AP FU........ Apalachicola.. .CO Jacksonville..: CO Jacksonville... AP Key West........ (X) Key West......... AP Miami............... (X) Miami............... AP Pensacola......... CO Pensacola......... AP Tampa....'........ CO Tampa.............. AP Titusville......... .AP Ga......... Atlanta............. AP Augusta............ CO Augusta....--- AP Macon............... CO Macon............... AP Savannah......... (X) Savannah......... AP Idaho... Boise................. CO Boise................. AP Burley..!......... AP Idaho Falls ... AP Lewiston........... CO Pocatello........... (X) m. Pocatello........... AP Chicago............. CO Chicago ....... AP Moline............... AP 733 1893-1947 ' 711 .1893-1945 ` 615 1 1939-1947 \ . 143 1872-1947 : 219 1940-1947 293 1872-1947 226 1938~1944d 6957 ' 1899-1947 3473 1935-1939 1122 1895-1947 ; 1112 1933-1947 2561 1935-1939 4853 Up to 1946 4899 1937-1947 146 1876-1946 545 1882-1945 463 1945-1947 : 451 1879-I942d 282 1942-1947 499 1937-1946 740 193I-194?d 1925 . 1935-1939 . 132 ' 1886-1947 ' 387 . 1887-1939 v 281 1939-1947 ! 534 , 1877-1947 ' 21 1929-1947 305c 1877-1934* . 346 1944-1947' . 579 1935-1939 116 1877-19475 , 22 .193&-1947 ; 90 1871-1940* 34 . . 1939-1947 164 1875-1947 . 100 Up to 1946 124 1935-1939 5398 1871-1947. 6379 . 1934-1947 6558 ' Up to 1946 . 4587 ' Up to 1946 4770 1889-1938 4810 1939-1947 : 229 1905-I940d ' 20 1940-1947.' 180 1872-1947 17 1943-4947; 128 , 1871-1947 . 20 " 1935-1939 23 1922-1947 104 1871-1947 29 1938-1947 23 1871-1947 48 1939-1947 253 . 1896-1947' . 13 '1940-1947 67 . 1879-1947 113 . 1943-1947, Ill . 1890-1940 12 . 1941-1946d 52 1935-1939 , 1020 1935-1939 195 1871-1946 424 . 1939-1947 408 1899-1947 . .432 1939-1947 116 1871-1945d . 56 1939-1947 . 2818 ` ' 1864-1939 2849 . . 1939-194? ` ; 4150 '' 1935-1939 4744 , 1935-1939 763 . , 1900-1944d 4522 1899-1947 4467 1938-1947 1872-1947 601 1Up to 1946' 615 1935-1939 594 - 1932-1947 105 107 103 . 94 103.. 104 .. 92 107: ' 103 93 107 . 99 118 117 io7 112; 102 107. 103 . 95 120 113 107 110 107 ' \ 97 113 * 104 ill : ' . 94 113. . 104 . 85 115 111 " ,i03 . 109 : 102 80 115 112 . 112 . 101 114 108 110 106 -* ' ' 79 101 106. 116 . . i03 105. 104 . 93 /- 99 . ' 105 104. 104 . " 95 101 98 ' . ' 88- 101 94 . 84 106 . 106 . 92 102 ' 104 105 . 94 100 95 96 . 100 , 89 103 105 98 : 98- 98 . 90 . 102 ' 93 106 ` 105' 105 102-' 105 ` 105 93 112 109- 95 104 94 100 88 117 : 105 103 92 106' 105 107 92 106 94 ,*85 95 .95 , 78 . 78. - 80" ! ;f ' 5.4 8.0 95 : 90 -- 65 : - ioi 76'- 6.0 105 72 100 70 iio 78' 95 :. 76 - ft.i . : 95 ' ; 78 6.2 ios - '70 90 105 90 : ,85 ;)oo ' 65 '* 'r: : 74 7.9 7 * .70 65 ' 70 5.8- ioo -72 ' 7.9 , 85 ` 68 . `65 10.7 91 " ; 70 ' 95 64 6.9 " 95 '65 ' 95 65 ' 6.3 95 65 .93 75 95 95 . 75 . 7.4 78 ' 5.9 95 80 85 78 ' 8.4 . 98 78 \6i ; 79 ` : 8.7 95 5 95 ' 78 - ` 78 ** 7.4 95 - ie ' 98 . 76 ' 95 . 7* 95 78 95 ' 65 7.9 8.6 5.8 95 65 95 65 68 78 ' `95 : ' 75 ' 9;5. ' 96 - ' 76 - `262 CHAPTER 12 1952 Guide 4 Table 3. , Summer Climatic Conditions* (Continued) Suggested Design Wet-Bulb and Dry-Bulb Temperatures Col. 1 State Con. 2 Station1* . Con. 3 Con. 4 Eleva Period tion* Recobd*1 Ft Con. 5 . Con. 6 ^ Con. 7 Con. 8 Con. 9 .Highest Temp. Ever . Recorded" Design^ Dry-Bulb Temp, on T-A.C. 2\% Basis' Design Dry-Bulb Temp, in ' Common Use* Design -Wet-Bulb Temp, in Common Use* Average Summer Wind Velocity* F F . F F . Mph Til AP Springfield.... .00 Springfield___ AP CO Fort Wayne... CO AP Indianapolis. .00 Indianapolis.. AP Terre Haute.. CO Terre Haute... AP Davenport....' OO AP OO CO OO AP OO Dodge City... OO AP Topeka........... .OO AP Wichita........... OO AP Ky......... Louisville....... OO AP La....... New Orleans.. OO AP Shreveport-- .AP OO Portland......... OO AP Md........ Baltimore....... OO AP , . . OO AP Nantucket___ OO , AP OO OO AP .OO AP Marquette----- <X> Minn.... Duluth............ (X) AP Minneapolis... oo- AP St. PauF........ oo AP Mias....... Meridian......... (X) AP Vicksburg....... OO Vicksburg....... ..AP Mo....;. Columbia....... OO AP AP OO St. Louis........ AP AP Mont.... BiHinpn.;........ AP AP OO Helena............ Kali*pell......... OooO AP Nebr.... Lincoln........... OO Lincoln........... North Platte.. oAPo AP Omaha . .. OO Omaha . .. AP - Valentine........ OO Nev....... Elko................. AP AP OO Reno................ AP OO N. H... Concord.......... oo Concord.......... ..AP 660 1935-1939 111 603 1879-1947 110 608 1930-1947 109 464 1897-1940, 108 885 mi-i94id 106 970 1935-1939 107 . 816 1871-1946 106 . . 800 1932-1946 107 1146 1893-1946 110 589 1941-1946 , 203 648 1872-1947 111 979 1935-1939 111 740 1874-1947 110 637 1872-1948. 113 1093 1889-1944d 111 1098 1940-1946 108 1425 1885-1947 - 116 2515 1874-1942d 109 . 2599 1942-1947 109 991 1887-1947 114 883 1946-1947 108 1497 1888-1939 114 1423 1939-1947 109 563 1871-1947 107 544 1937-1947 103 85 1874-1947 102 8 .. 1937-1947' 100 179 1935-1939. 109 100 1873-1947 93 185 ..1885-1940 103 65 1940-1947 99 114 1871-1947 107 43 1935-1939 105. 356 1670-1935 104 45 1936-1947 101 45 1886-1947 92 48 .1946-1947 ' 82 615 1874-1946 104 . 1000 1873-1933 104 632 1934-1947 105 861 1910-1947 102. 863 1940-1947 98 721 1874-1947 108 1133 1874-1947 106 1413 1941-1947 95 945 1890-1947 108 873 1938-1947 104 951 1871-1933 104 708 1937-1947 104 410 1889-1947 105 298 1939-1947 105 316 1874-1947. 104 266 1941-1947 104 739 1889-1947 111 787 1939-1947 102 780 1935-1939 . 112 646 1871-1947 110 597 1930-1947 111 1270 1935-1939 105 3584 1935-1947 106 5538 1931-1947 100 2498 1880-1947 108 4175 1880-1940 103 3004 1897-1947 101 2629 1935-1939 108 1189 1887-1947 115 1185 1933-1947 115 2815 1874-1947 109 2788 1935-1939. 109 1219 1873-1935d 111 1009 . 1935-1947 114 2627 1889-1947 no 5079 1935-1939 102 1882 1937-1947 117 4588 1905-1942 106 4417 1940-1947 105 4293 1871-1947. 108 343 1871-1941d 102 359 1941-1947 i 99 . 94 96 89 9i 95 ioo 93 93 98 91 87 89 9i ioi . 97 96 92 85 97 ioi 98 98 92 108 93 ' 96 -98 95 95 95 95 95 95 95 95 95 95 95 ioo ioo 95 95 ioo 90 90 95 92 95 95 95 95 93 93 95 95 95 05 ioo ioo . 95 90 95 95 95 95 95 95 95 95 95 90 76 77 78 75 76 . 78 78 78 78 78 78 78 78 78 75 , . 78 80 78 ' 70 73 78 75 75 75 Si. 73" 75 73 73 75 75 79 ' 78 8.2 7.6 8.9 8.6 li.8 7.2 6.9. 7.6 8.7 7.4 12.5 9.5 10.2 4.6 6.4 76 78 70 67 . 78 . 78 6.i 9.5 8.7 8.i 9.7 8.i 65 . 7.2 73 ... - 4.9 Cooling Load 263 Table 3'. Summer Climatic Conditions* (Continued) Suggested'Design Wet-Bulb and Dry-BuTb'Temperatures Col. 1 State Col. 2 Station1* Con. 3 ' Eleva TION Ft Con. 4 ' Period of Record* Con. 5 Con. 6 - Con. 7 Col. 8 Highest Temp. Ever Recorded* Design Dry-Bulb Temp, on' T.A.C. 2*% Basis . Design ` Dry-Bulb Temp, in Common Use* Design Wet-Bulb - Temp, in Common USE* F . #F F F Con. 9 Average Summer Wind Velocity* Mph N. J..... ' Atlantic City. CO Camden........: AP Newark........... AP Trenton.......... CO N. M.... Albuaueraue.. CO Albuqueraue.. AP El Morro___ .AP Rodeo.............. .AP Roswell........... CO lucumcan.... AP N. Y... Albany............ (XI Albany........... AP Binghamton.. CO Binghamton.. AP Buffalo............ .AP Canton__ :... .CO ./ Elmira............ AP New York__ CO Oswego............ CO Rochester....... CO Rochester....... AP Syracuse....... <X Syracuse......... AP N. C.... Ashville............ <X> Charlotte........ CO Charlotte........ AP Greensboro... AP Raleigh........... CO Raieifh............. AP Wilmington___ CO N. D.... Bismarck........ OO - Bismarck......... AP ' Devils lake... (X) Dickinson....... .AP Fargo................. .AP Pembina........... AP Wiliiston........... (X> Ohio___ Akron................ AP Cincinnati........ <X> Cincinnati........ .AP Cleveland......... .CO Cleveland......... AP Columbus........ (XI Columbus....... AP Dayton............. CO Dayton............. AP Sandusky......... (X) Toledo.............. CO loledo............... AP Ufcla.... Ardmore........... .AP Oklahoma Citv.CO Oklahoma Citv.AP TuIra ............... AP Waynoka.:___ .AP Ore........ Arlington......... AP Baker................ OO Baker................ .AP Eugene............. OO Eugene............. AP Medford............ OO Medford........... AP Portland........... (X) -Portland........... , AP Roaeburg......... <X) Curwensville... AP Erie................... .CO Erie................... AP Harrisburg....... AP Philadelphia... .CO Philadelphia... AP Pittsburgh....... (X) Pittsburgh....... .AP Reading............ (X) Scranton........... (X) Sunbury........... AP Block Island... .(X) Provident** <x> Charleston....... (X) Charleston....... .AP 45 20 25 144 5022 5319 7120 4116 3643 4054 114 280 915 836 726 458 948 425 363 609 . 560 465 404 2280 809 757 896 405 446 78 1675 1655 1481 2599 900 830 1919 104 772 488 669 813 812 820 1086 1002 608 668 626 762 1264 1311 686 1529 881 3501 3374 366 368 1428 1343 98 25 523 2219 771 736 339 200 18 929 1284 311 877 448 46 77 59 51 1874-1947 1936-1939 1931-1947 1866-1946 1931-1933d 1933-1947 1935-1939 1935-1939 ' 1905-1947d 1935-1939 1874-1947 1938-1947 1891-1946 1942-1947 1935-1939 .1906-1947 1935-1939 .1871-1947 1871-1947 1872-1947 1935-1939 1902-1940 1940-1947 1902-1947 1878-1947 . 1939-1947 1928-1947 1887-1947 1944-1947 1871-1947 1875-1940 1940-1947 1904-1947 1938-1939 .1935-1939 1935-1939 1879-1947 1935-1939 1870-1947 1931-1947 1871-1946 .1930-1946 1878-1946 1939-1947 1883-I943d 1940-1947 1878-1946 1871-1947 1940-1947 1935-1939 1890-1947 1939-1947 1932-1947 .1938-1939 1935-1939 1889-1947 1939-1947 1890-1942 1942-1947 1911-1929 1929-1947 . 1874-1947 1940-1947 1877-1947 1943-1947 1873-1946 1938-1939 1938-1939 1871-1947 1940-1947 1875-1947 1938-1947 1913-1947 1901-1947 1935-1939 1881-1947 1904-1947 . 1871-1947 1940-1947 104 . . 105 9i 104 : 89 106 : . 99 * . 101 93 92 84 104 97 107 .107 104 . 97 99 88 103 97 , 95 .// .88 99 96 - 88 102 100 . ' 102 ` 98 . 89 : 102 ?. 97 ;l - 88 99 103 103 ' 93 101 91 104 102 ' 93 103 . * 114 109 . 96 112 112 94 115 93 109 ; 92 110 . 101 ` 88 108 108 ' , 94 100 ' 107 ' 90 106 100 90 108 .99 105 105 100 . 91 110 * 99 113 109 99 109 100 115 . / 103 111 95 104 103 90 104 . 105 88 110 115 \ 95 107 105 .~. r . 87 109 90 *" 82 98 96 ' 85 103 91 106 100 103 102 88 105 103 101 89 93 100 104 103 9i ' . ". ` ' . . . . . 95 ' 78 - 9595 95 - 95 75 78 70 ' '70' . 93 75 7.5 95 ' 75 ' 93 90 73 73 8.2 95 75 12.5 93 73 95 < 75 93 75 93 75 95 ' 78 6.6 95 78 95 78 6.3 95 '78 ` 8.4 95 73 95 70 95 75 95 73 95 ' `75 . 95 78 5.6 95 75 li.i 95 7\ 6 . 95 78 95 75 ' 95 75. ioi 77 9.8 ioi 77 90 66 90 68 95- 70 90 68 6.5 90 66 93 75 ' 95 95 78 9.7 95 75 8.9 95 75 95 75 95 75 93 75" 9.5 95 78 ' 9.8 264 CHAPTER 12 1952 Guide Col: 1 State' Table 3. /Summer Climatic Conditions* (Concluded) Suggested Design .Wet-Bulb and Dry-Bulb Temperatures ' Col. 2 , .. Station*5 - Col. 3` Ele vation Ft Col. 4 Period op Record*1. . Col. 5 t . .Col. 6/! . Col. 7 . ,'Col. 8 - Highest. Temp. Ever Recorded Design'- Dry-Bulb .Temp, on T.A.C. 24% Basis _ Design DRy-BuLB. Temp, in ' Common Design Wet-Bulb Temp, in Common Use* . - "F f ; - 1 "F F Col. 9 Average Summer . Wind Velocity* . Mph s. c....: Columbia......... CO Columbia......... .AP. S. D...... Huron............... CO Huron............... A P Rapid City----- CO Rapid City___ AP Tenn.... Chattanooga... .<X) Chattanooga... .AP Knoxville...... (X) Knoxville......... .AP Memphis ... . CO Memphis.......... AP Nashville......... CO Nashville___ .. AP Texas/.*. Abilene......... . CO Abilene......... .. AP Amarillo........... CO Amarillo........... AP Austin............... CO Austin............... AP Brownsville___ CO Brownsville___ AP Corpus Christi. (X) .Corpus Christi .AP Dallas............. CO Dallas............. AP Del Rio......... El Paso........... CO El Paso........... .AP Fort Worth... (X) Fort Worth... AP Galveston....... .CO Galveston....... AP Houston........... CO Houston........... AP Palestine.......... CO Port Arthur... <;o Port Arthur... AP San Antonio.. CO San Antonio.. .AP Waco................ AP Wink............... AP Utah-... Milford........... AP Modena........... .CO v Salt Lake City..CO Salt Lake City.AP Vt. CO Burlington.... AP Va......... .CO Lynchburg___ CO Lynchburg___ AP Norfolk........... .CO. Richmond.... CO Richmond . AP Roanoke......... AP Wash... EUensburg___ .AP North Head.. .CO Seattle............. CO Seattle............. .AP Spokane......... CO Spokane......... .AP Tacoma........... CO Tatooeh Island.CO Yakima.......... CO Yakima.......... AP W. Va... Parkersburg.. CO Wise.. .. Green Bay.... CO La Crosse....... CO La Crosse....... .AP Madison.......... CO Madison......... AP Milwaukee.... CO Milwaukee___ .AP Wyo....... Cheyenne....... CO Cheyenne....... AP Lander............ CO Lander............ AP Rock Springs .AP 401 227 1342 1287 3309 3220 962 675 1024 1007 348 267 714 610 1748 1756 3686 3696 625 625 140 25 21 45 732 520 1020 3792 3956 708 728 128 *9 198 73 555 64 21 770 800 513 2811 5095 5472 43464254 . 1887-1947. 106 :. 1939-1947** : 104 v -1881-1938d 111 r: 1938-1947 110 .. .1888-1947 106 1939-1947 108 1879-1947 . 163 '1940-1947 105 1871-1942d 104 ' 1942-1947 102 : - 1872-1941d 106 1941-1947 v . 105 1871-1947 106 : 1939-1947 104 1885-1944 ` in 1940-1947 109 1892-1941 . 107 - 1941-1947 106 . 1897-1942 - 109 , 1942-1947 104 lS22-1943d 102 1943-1947 100 1887-1942 . 105 1943-1946 101 . .1913-1940 110 - . 1940-1947 109 1905-1947 111 . 1887-1942 106 - 1939-1947 104 1898-1939 112 . -.1940-1947 *. no ... 1871-1947 101 .1939-1947 101 1888-1947 108 ..: 1932-1947 105 1881-1947 108 , 1917-1947 102 1944-1947 *. 98 188S-1941d 107 1942-1947 104 . ' 1931-1947 Ill 1935-1939 . 110 - . .1935-1939 103 1901-1947 101 . 1874-1947 105 . 1928-1947 106 : .94 .::94 . , 96'. . 97 : 96 . . 99 .. 97 . .93 . ' ' 98 .98 99 !94 '. 95 335 -1943-1947 24 1874-1947 * 644 '1874-1944 . 951 1944-1947 91 1871-1947 180 1897-1947 172 71929-1947 1194 1935-1939 . 1731 1935-1939 ' 199 1884-1947 ; 104 ., 1890-1947 ' 47 1928-1947 2030 1881-1941 1974 1941-1947 279 1897-1947 : 110 1883-1947 ; 1160 . .1928-1946 '* 1066 " 1944-1947 ' 685 1888-1947 598 1886-1947 725 ' 1872-1947 677 1943-1947 1008 1858-1947 884 1935-1939 744 1870-1947 707 1927-1947 6144 1873-1935 6161 1935-1947 5448 1891-1946 5568 1936-1947 . 6746 .1932-1942 . 101 106 . 100 ` 105 107 104 , : , ,92 103 ` *: 90 105 - " '90 97 100 99 -108 ; :8i ` 104 . - : 92 98 88 *; 110 103 * 106 ' 104 108 * 96 91 107 106 89. 105 106 . ' 87 100 100 ; 89 102 97 98 . 87 . Y !. . ': . * ' . 95 " ' ' 75 ' 95 75 95 ` 70 .95 76 \ 95 . 75 - 95 78' * 95 78 ioo 74 * ioo 72 . 100 .78 ioo V 80 95 80 ioo -;.78 . ioo 78 100 69 ioo ..78 /" .95; 95 78 100 78 95 79 ioo ' 78.. 95 , 95 65 65 ' 90, 73 95 ' 78 95 . 75 .. 95 * 78 95 75 95 * 76 . 85. 85 65 '. 65 93 ' 65..' 85 64 95 . ' 65 95 75 95 . 75 95 75 95 75 95 75 * 95 . '95 65 ' 65 10.3 . 7.9 5.6 5.7 7.3 ' 11.8 7.6 9.3 8.4 9.5 -* 9.7 /. 8.8 7.8 9.8 8.5 i6. i 6.4 7.7 6.5 ... >. i 5.2 9.2 6.4 7.9 9.8 9.2 Cooling Load 265 .. NOTES FOR TABLE 3 * Data compiled from U. 8. Weather Bureau Data and various other sources. b Column 2. The station designation AP or CO indicates airport or city office station, respectively. ' c 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 shown in Column 5, 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^ applies only, to airports, as these data for city stations are not avail-, able at this time.' The temperature shown is the maximum hourly outdoor temperature which has been' equalled or exceeded 24 percent of the total hours of June, July, August'and September (or the 5-year period 1936-1939, 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. . ' r f Columns 7 and,8 record wet and dry-bulb temperatures in use by A.S.H.V.E. Membera asreported 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: . ' * . * The average wind velocities indicated in Column 9 were furnished by the U. 8. 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 Fas the de sign wet-bulb temperature which has been equalled or exceeded 5 percent of the hours for period 1935-:1939.. 1 Blank spaces indicate data not available. ' 7' ' - Table 4. Ventilation Standards* Application S * Smoking' - / . Cfm per Person : "Cpm per. q Ft ov, Floor. Recommended Minimum1* Minimum*5 Apartment Average..........7..!___ Banking Space........................................... Barber Shops........................... ~................ Occasional.......... Considerable___ 20 '.. 30 . ' 10 - - 15 *o . Y * ; Brokers' Board Rooms..................... Very Heavy....... - ,50 ' Corridors (Supply or Exhaust).............. Directors' Rooms..................... ................ Extreme.......... '.. ` 50 Drug Stores*1.......................... Considerable.... 10 Garages....................................................... . 10 10 25 74 10 * 74 20 25 30 74 n 6133 6^25 0.05 o.io i!o' Residence.................................. Laboratories4............................................ Some.................... 20 . Private.......................................... Considerable___ Restaurant Cafeteria4.......................... Dining Roomd..................... Considerable___ School Rooms......................................... 30 - 1125 25 is 25 1120 0.33 2.0 1.25 0^25 ' Toilets (Exhaust)................................... 15 . 10 2.0 ^ Taken from present-day practice or large air conditioning companies. b When minimum is used,1 take the larger of the two. c See local codes which may govern. 4 May be governed by exhaust! e May be governed by special sources of contamination or local codes. * All outside air recommended to overcome ex plosion hazard of anesthetics. . * * -- applications are summarized in Table 4. For further general applications, a basis of estimating the cfm per person may be taken as: 1. People not smoking........................................... 7\ Recommended 5 Minimum 2. People smoking.................................... .......40 Recommended 25 Minimum The cooling load due to the introduction of outside air for ventilation is 266 CHAPTER 12 1952 Guide determined once the indoor and outdoor design conditions are fixed. Cal . culations will be discussed subsequently. , ,/ INSTANTANEOUS HEAT LOAD The total cooling load is frequently divided for convenience into two components, sensible heat and latent heat. While this subdivision is not -imperative, past practice has found it convenient. A gain of sensible heat is considered to occur when there is a direct addi tion, of heat to the enclosure by any one or all of the mechanisms of conduc tion, convection, and radiation. A gain of latent heat 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 Fig. 1. Definition of Solar Angles the rate of condensation and the latent heat of condensation; this product, expressed in Btu per hour, would be called a latent heat load. As a further example, the infiltration of outdoor air with a high dry- bulb temperature and a high humidity ratio, and the corresponding escape of room air at a lower dry-buld temperature and a lower humidity ratio, would increase both the sensible heat load and the latent heat load.' ' SOLAR RADIATION Magnitude of Solar Radiation If a plane surface were set perpendicular to the. sun's, rays. (t.e.,. for normal incidence) outside the earth's atmosphere, it would receive solar radiation of about 420 Btu per (hr) (sq ft). A similarly oriented surface, at the surface of the earth, would receive considerably less solar energy because a large part of 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 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- '. Cooling Load 267 poses, is confined' to the radiation spectrum between 0.3 and 2.3 microns. 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 7t, received by a surface at the earth, is the sum of la and Id, where . Id = K Ion = the direct or beamed solar radiation, Btu per (hour) (square, foot of receiving surface). . . IDo = the direct solar radiation normal to the sun's rays, Btu per (hour) (square '. foot of receiving surface). Table 5. Values of Ido, Direct Solar Radiation Received at Normal Incidence at the Earth's Surface, and Values of Id, Diffuse or Set Solar Radia tion. Received by Variously Oriented Surfaces Btu pin (hour) (bquarh foot) BOLAB . Altitude Dbobbxs Fob Clbab Atmosphbbbs Dibbct* Normal Radi* atioh . DxrrusE ob Set Radiation' . Fob Industrial Atmosfbebbs . Direct*1 Nobmal Radi* ATIOH . Dxftubb ob-Skt Radiation ' AM -* i, 6 10 . 16 20 26 30 36 * 40 46 60 60 70 80 . 00 67 123 166 197 218 235 248 258 266 273 283 289 . 292 294 NE 8 6 11 11 20 14 27 16 32 16 35 4 8 11 13 15 17 36 17 17 3$ 19 18 36 21 19 35 23 19 33 26 21 28 . 27 22 23 29 -- , -- -- ------ w Hobxz. 47 7 14 10 19 12 23 . 13 26 15 28 16 30 17 31 18 82 19 33 21 .84 , 23 36 -- --. ---- 84 68 80 103 . 121 136 148 168 165 172 181 ' 188 195 200 NE 4 11 8 22 11 . 28 13 36 16 43 18 47 19 60 20 50 21 49 22 47 22 41 22 34 ---- 8 W Hobxz. 63 97 13 9 17 12 21 .16 24 18 27. 21 80 23 31 26 . 84 27 37 30 41- 34 -- - .-- 9 18 24 31 38 44 48 63 ' 65 68 63 69 " pL - N W S E Hobiz. N W 8 E Hobiz. Moon'3* proposed standard lor sea level, 20 mm preapitable water vapor, 300 dust particles per cu cm, 2.8 mm Hg partial pressure of ozone. b For 40 deg north latitude on about August 1. c Based on observations by ASHVE Laboratory at Cleveland on cloudless days during which the observed normal incidence values closely approximated the normal incidence values tabulated. d Derived from recommended design sol-air temperatures4 for New York City fora horizontal surface with absorptivity of 1.0. ' . Id = 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. Such radiation is usually diffuse. The diffuse radiation strikes af all angles. /, = total incident solar radiation, Btu per (hour) (square foot of receiving surface). . K = cosine of the angle of-incidence, 0. For a vertical surface, $ is defined in . Fig. 7. Standardized, practical-purpose values of the direct solar radiation /Dn incident upon a plane perpendicular to the sun's rays at the earth's surface, have been proposed by Moon.* Table 5 gives these values. They are 268 CHAPTER 12 1952 Guide 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.' Values typical of a humid industrial area derived from sol-air data for New York City* are also given in Table;5. 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). Oh the other hand, values 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 latitude on August 1 (18 deg decimation, north) are given in Table 5 for the two types of atmospheres. These are based.upon observations made on cloudless.days in Cleveland over a'period of several^summers. Since less extensive data were available for industrial atmospheres, there is more uncertainty regarding these values. In both instances, the values.include an unknown amount of ground reflection, which may be. expected to vary with location.' It should be noted that- clouds which do not obscure the sun tend to increase diffuse radiation vialues. Nearby buildings may reduce diffuse irradiation by partial shading. i Calculation Tables .; / The irradiation of a surface by the sun is the product of Id*, the direct normal radiation (see Table 5), and the cosine K of the incident,angle, 0. For horizontal surfaces, the.cosine K equals the sine of the solar altitude. For vertical walls, A is a function of the solar altitude 0 and the wall solar azimuth 7, thus . .. ; ... . _ K = cos B = COS0 cos y (1) These three angles are defined in Fig. 1. Values of K are given in Table 6 and values of /3 and y are given in Table 7 for 18 deg north declination (August 1). To compute K values for orientations other than those given in Table 6, third angle <#>, the solar azimuth, is required. In this discussion, <t> will be measured east from south in the morning,- and west from south in the after noon. Hence, <j> values are equal to 90 deg minus the y values for an east or west facing wall, except when Table 7 shows the south walls to be in the shade. In thus case <t> equals 90 + y, that is, <f> is greater than 90 deg. The wall azimuth ip is the angle, measured east from 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, \p 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:/ For walls facing west of south: y<t> ~~ ^ a.m. y = $ + p p jn. y = <t> + $ bhl * y = <p -- tp p.m. CoolingLoad 269 Table .6. / Values of K, the Cosine of the Incident Angle, fob Variously - Oriented Walls and a Horizontal Surface Computed for 18 Deg Declinationt North {August /). - Sun Time 30 Deo North Latitude Cosine E or the Incident Angle - AM A - 6 Ajn. . 7 . 8 9- 10 . 1112 6 p.m. 5. 4 3 2 1 N 0.267 0.144 0.030 .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 SW ^ Horis. 0.068 . 0.144 0.192 0.208 .0.147 0.156 0.367 0.566 0.737 0.866 0.951 ^ 0.978 . pi - N. NW : W SW S * SE Horis.- Sun Time -AM -- A : ' 6 SJD. 6/ 7 8- - 7 p.m. 6 5 4 93 10 2 11 1 12 pi -- 40 Deg North Latitude Cosine K or the Incident Angle .N . . NE -E SE 8 . SW. 0.406 0.237 0.079 0.934 0.840 0.705 0.533 . 0.337 0.129 . 0.914 0.951 0.919 0.824 0.673 0.476 0.246 0.000 0.358 0.605 0.694 0.631 0.614 0.542 0.424 .. 0.265 0.069 0.196 0.292 0.354 0.875 0:076 . 0.265 N NW W SW S SE Hobxs. 0.009 0.199 -0.391 0.566 0.713 0.829 0.903 0.927 Horis. ,, Sun Time AM - A 5 ajn. 6 7 8 9 10 11 12 7 p.m. 6 5 4 3 2 1 pL -- N 0.385 0.199 0.010 `- N 50 Dbg North Latitude Cosine K or the Incident Angle NE E' ' SE s- 0.922 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 NW W SW ' S SW 0.183 0.375 SE ' Horis. - 0.078 0.233 0.399 0.645 0.669 * 0.766 0.829 - 0.848 Horiz. Treat negative values of 7 as if they were positive. If 7 is greater than 90 deg, the wall is in the shade. ' Values of K for other seasons and latitudes may be found in. the litera ture,6 or may be computed from data given in Hydrographic Office Bulletin No. 214, Tables of Computed Altitude and Azimuth6 and the Ephemeris of the Sun.7 Table 8 shows the variation of solar declination during the months ordinarily requiring cooling. - Example 1: Find the solar azimuth 4> at 6:30 pun. at 40 deg north latitude on August 1st. . ' . Solution: From Table 7 in the column of 7 for a wall facing west 4> for 6:00 pjn. 270 CHAPTER 12 l '' , 1952 Guide Table 7. "Values of the Wall Solar Azimuth, y, fob Variously Oriented Walls and Solar Altitude . ' Computed for 18 Deg Declination; North -{August 1) , Sun Time AM-* 1 6 a.m. 7 8 9 0 p.m. 5. 4 3 .10 2 11 1 12 T PM -* Sun Time AM-* i 5 a.m. 6 7 8 7 p.m. 6 5 4 '9 3 10 2 11 1 12 r PM -+ Solar ~ Altitude 0 Degrees 9.0 21.5 34.5 47.5 60.0 72.0 78.0 . Solar Altitude 0Degrees 0.5 11.5 23.0 34.5 45.5 56.0 64.5 68.0 30 Deo Nort^. Latitude ,Azimuth Angle y Degrees - N. NE E. SE S 74 81 88 shade 29 36 43' 51 62 83 shade 16 9 2 6, ' 17 38 90 N NW W ' 40 Dsg North Latitude 61 ` 54 47 ' 39 28 7 .45 - SW shade 84 73 52 0 S .Azimuth Angle y Degrees ' SW shade 45 SE - N NE E 66 76 85 shade N 21 31 ' 40 50 61 76 shade 24 14 5 5 16 31 55 90 ` NW ' W, SE s. ' SW ' 69 69 50 shade 40 85 29 74 14 59 10 35 45 0 SW . . S shade 80 45 SE Sun Time AM --* 1 5 a.m. 6 7 8 7 p.m. 6 5 4 9 10 .11 12 3 2 1 t PM -- Solar Altitude 0 Degrees 50 Deo Nobth Latitude .' Azimuth Angle y Degrees N NE E SE S 4.5 13.5 . 23.5 33.0 42.0 50.0 56.0 58.0 67 78 90 shade N 22 33 45 57 70 87 shade NW 23 12 .0 12 25 42 64 90 W 68 . 57 45 33 20 3 19 45 SW 90 78 - ' 65 48 26 0 's SW shade 71 45 SE . Table 8. Approximate Solar Declinations in Degrees Date April 1 April 15 May 1 May 15 Declination 4.5 10.0 15.0 19.0 Date June 1 June 15 July 1 July 15 Declination ' 22.0 23.5 23.0 21.5 Date Aug. 1 Aug. 15 . Sept. 1 Sept. 15 Declination 18.0 14.0 8.5 3.0 . Cooling Load 271 is 90 + 14 = 104 deg, and at 7:00 p.m. is 90 + 24 = 114 deg. . By interpolation, <t> for 6:30 p.m. is 109 deg west of south (at 5:30 a.m. 4> would be 109 deg east of south.) Example 8: Find K for a wall facing 18 deg east of south at 10:00 a.ni. on August 1 at 50 deg north latitude. ` Solution: The wall azimuth is 18 deg. The solar azimuth is 48 deg east (Table 7). The wall solar azimuth is 48 -- 18 or 30 deg. From Table 7, f} is 50 deg. Then r K = cos p cos y = cos 50 X cos 30 = 0.643 X 0.866 = 0.557. ' Example 3: Find K for the wall in Example 2 at 3:00 p.m. ,. Solution: The solar azimuth is 65 deg west. The wall solar azimuth is therefore 65 + 18 = 83 deg. The angle p is 42 deg. K = cos 42 X cos 83 = 0.743 X 0.122 = 0.091. Example 4'- Find the total solar irradiation for the wall for the conditions of Example S. Solution: Use clear atmosphere solar intensities. ' At 50 deg altitude, the direct normal radiation is 273 Btu per (hr) (sq ft). Then, . 7d = K X 7n. = 0.557 X 273 = 152.0 Btu per (hr) (sq ft). By linear interpolation, the diffuse irradiation is 7d = 25 + M (33 - 25) = 26.6 Btu per (hr) (sq ft). . The total solar irradiation is . . 7. = 152.0 + 26.6 = 178.6 Btu per (hr)(sq ft). . PERIODIC HEAT FLOW THROUGH WALLS AND ROOFS ' The calculation of heat flow, through a structural section of a building exposed to the weather, requires consideration of the diurnal cycles of solar irradiation and air temperature. These cycles and other factors lead to a periodic variation in the instantaneous rate of heat flow into the weather surface, and a related periodic variation in the rate of heat flow into the air conditioned space. Because of heat capacity and other factors, these heat flow cycles are, in general, out of time phase and unequal in amplitude. In order to calculate the rate of heat entry into the weather surface of a building, it is necessary to know: ' 1. The intensity of direct solar radiation striking the surface. 2. The absorptivity (or reflectivity) of the surface for direct solar radiation. 3. The intensity of diffuse or sky solar radiation striking the surface. . 4. The absorptivity (or reflectivity) of the surface for diffuse or sky solar radia tion. 5. The rate at which the surface emits radiation to the sky and other surround ings. 6. The rate at which the surface absorbs the low temperature radiation emitted . by the Bky and other surroundings by virtue of their temperatures and radiating characteristics. ' 7. The temperature of the surrounding air. 8. The temperature of the outer building surface. 9. The unit convective conductance for heat transfer between the air and the building surface. ' The Sol-Air Temperature . The complex interrelationship of the above factors can be considerably simplified through the use of the sol-air temperature concept. The sol- 272 CHAPTER 12 1952 Guide air temperature t,, is the temperature of the outdoor air, which, in the absence of all radiation exchanges, would give the same rate of heat entry into the surface as would exist with the actual combination of incident solar radiation, radiant energy exchange with the sky and other outdoor sur roundings, and convective heat exchange with the outdoor air. . The sol-air temperature is developed as follows: .' 1.The basic heat balance equation which includes the factors listed, gives the rate of heat entry into the weather side of a sunlit building surface, and is written:-- . ) = ad/d + "d/<l + /,(<<. - (l) + aMe - lBl, Btu per (hr)(sq ft) . (2) where - a => absorptivity (dimensionless) of weather side of wall or roof for incident , solar radiation. Subscripts D and d refer respectively to direct and diffuse. I = incident solar radiation, Btu per (hour) (square foot), Subscripts D and d refer respectively to direct and diffuse. = outside air temperature, Fahrenheit degrees. ' ;L = temperature of weather surface of wall or roof, Fahrenheit degrees. /, = unit convective conductance. of weather, surface,.Btu per (hour)(square foot) (Fahrenheit degree). '" B. -- low temperature radiant energy falling on surface from outdoor surround- ings.Btuper (hqur)(square foot of receiving surface). .' iL =* emissiviiy of.surface at temperature fi, (also equals absorptivity for Rm), dimensionless. ' , ' Bl = low temperature radiant energy emitted by.a black body at temperature ty, Btu per (tour)(square foot). .. . . 2. The sol-air temperature is defined as: gp/p + Otdld d- *l(B. -- Bl) U+ (3) 3. The' instantaneous' rate of heat entry into the weather surface of the wall or roof becomes: ' : ' ' ' The term et(B. -- Rj.) is difficult to evaluate,, since U., on which Re depends, cannot be found until/. and the thermal properties of the struc- ture are known. However, it may be estimated from experimental ob servations of surface temperatures of walls and roofs which appear in the literature8,9 on periodic heat flow. RL can then be found from Chapter 5, Table 5, and cL can be found from Table 3 of the same chapter; The term R, represents the low temperature radiant energy from, outdoor surroundings which falls on the surface in question (l is - -the fraction absorbed). In the case of horizontal surfaces, all of this energy comes from the atmosphere of which water vapor is the principal radiating com ponent. For horizontal surfaces, Brunt's10 correlation of a long series of observations shows R, to be dependent upon the dew-point temperature. For the commonly used design dew-point 67 F, his empirical equation CoolingrLoad 77 , 273; Table 9. . Design Sol-Aib T^PEBATtraESFOB:40. North Latitude and. 18 D .DECLINATION, NORTH (AuqDST11) FOB. ClEAB AND InDD8TB1AL ATMOSPHERES . Sol-Aib TempBbatdre/ Fahrenheit Degree* 'Ant8 &7N iTlME Sur face ' Cle^b Atmospheres Hob. N". : ;s'.. W 'Industrial Atmosphere* Hob. -> \ SW j*' i::, ,'ftxb 0.0 " ois; 0.25! 0^25 0.25 ois 0i5 0.25 0.25 0.26 ois .. 12 " -v. 1-ajn. -2 3 4 * 6`` 0 7s . 9 10 11 12 1 pan. 2 3 4 8 -6 7 8 9 10 11 : 77-' 76 76 75 74 74 74 76 77 80' 83 87 90 93 94 . 95 94 93 91. 87 85 83 81 79 77 76-. 76' 75 74 74 85 102 119 . 136' 149 160 165 166 160 151. 136 120 .102: 87 . 85 83 81 79 77 77 ` ; :-7i - 77: 76 76 : 76' - 78 . 76 76 *-76 ' 76 : 75 75 75 75 74 74 74.. 74 75 76 ' ` 74 74 ` " 85 112 76 ; 76 83 132 79 * 78 81 137 86 81: 85 134 99 `85 88 92 96 * ' .98 98 124 111 96 98 99 110 88 119 62 124 . 66 125 ., 117 121 .135 100 100 114 98 98 103 101 96 . . 97 : 102:! .93 93. .88. , : .87 . 87;, 149 154 150. 129 89. 85 83 81 . 79 85 83 - 81. 79 85 83 81 . 79 85 83 .81 . 79 TJ 78 - 7675 ,74 TJ , . 78 76 75 74 - 77 '* 76,...76 75 74 77 ,76. . 78 75 . 74 77 ' 76 .. . 76 75 74 74 82 95 ` 110 123 ' 75 ' 80 81 82 85 75 95 113 120 120 74 ' 74 77 76 80 79 80 83 96 86 135 1 88 115 105 90 145 92 108 113 95 150 95 98 117 .. 98 151 98 101 119 114 146 99 101 116 126 138 127 113 99 87. 100 99 99 97 88 101 99 97 - 93 87 111 103 98 98 . 92 135 137 131 112 ; 88 . : 85 85 85 85 85 83 83 83 83 83 81 81 81 81 81 79 79 79 79 79 24 hr avg fm 83.1 100.1 86.5 95.8 92.3 . 95.8 103.4 86.0 92.9 91.2 92.9 * a = surface absorptivity, dimensionless. . '' ' . fcxo *=' unit surface conductance, radiation and convection combined, Btu per (hr) (sq ft) (F deg). b Values in this column are magnitudes of to, the outdoor dry-bulb temperature; gives R, as 82 percent of the hemispherical radiation emitted by a black surface radiating at a temperature equal to that of the outdoor dry-bulb temperature. For vertical surfaces, R, varies, since part of the energy is received from the ground, the temperature of which is .influenced by solar radiation. Few data for vertical surfaces are available. ' Because of the lack of data regarding R, and the difficulty of evaluating lCR, -- Rl), present practice in calculating sol-air temperatures is to compensate for the term by increasing /<*,. This.is a: rough approxima tion, since, during a considerable part .of the night, outdoor surface tem peratures are .at or close to the ambient air temperatures, "yet the radiation loss is of appreciable magnitude. Example 6: If fc, = 90F, a, = 0.7, /, = 200 Btu per (hr)(sq ft), /,, 3.0, find, the sol-air temperature for a roof when the dew-point temperature is 67 F. Solution: Previous experience indicates that the roof temperature under these conditions will be about 120 F. , equals 0.9. Using the tabular data of Table 4, Chapter 5, to determine B, and Bl: u _ go + 0 7 (200) + 0,9 (0.82 X 159 - 196) = m Q F Example 6: Find t, if compensation for cl(B, -- Bl) is made by replacing /,, with fao, the surface conductance for radiation and convection combined, equal to 4.0. Solution: t. = 90 + --^K)) = 125.0 F. 274 CHAPTER 12 1952 Guide _i - Based upon the solar data of Table 5, sol-air data have been computed for locations in clear and in humid industrial areas where the' design dry-bulb temperature is 95 F. As given- in Table 9, these are for 40 deg north latitude, 18 deg north declination (August . 1). Jtadiation exchange has been included with the convection transfer; a value of 0.25 was used for at//oro. The data for industrial areas are practically identical with solair data for New York City4 which were-derived from an analysis of U. S. Weather Bureau records for a 10-year period. A similar analysis for Lincoln, Nebraska* leads to somewhat higher sol-air temperatures than the clear atmosphere values given in Table 9 because of the -higher dry- bulb temperatures. .. Corrections for other conditions indicated by ('), are made as follows: 1. To adjust the data in Table 9 iot variations in U\ - a. Establish the value of question. the dry-bulb temperature, for the locality in .' . b. Determine W -- to. c. Add (algebraically) to' -- to to the data tabulated. 2. To adjust the data of Table 9 for other values of ai/fen'. interpolate or extra polate the tabulated data by direct proportion, using the column for at//e,, = 0.0. Sol-air temperatures are especially helpful in the calculation of periodic heat transfer, as will be illustrated in the material which follows. PRINCIPLES OF PERIODIC HEAT FLOW Calculation principles for periodic heat flow are dealt with briefly in this section; in the section which follows, practical tables are given to facilitate rapid design estimates. In addition to the rate o! heat entry into the out side building surface, these tables take into account the following factors: 1. The thermal conductivity of material. ' 2. The density, specific heat and character of material. . 3. Thickness of material. 4. Room air temperature. .. 5. Unit convective conductance between the inside surface and room air; and radiant heat transfer between the inside surfaces and other surfaces in the room. Time Lag The fundamental analysis of periodic heat flow is complicated when compared with steady-state calculations on account of the time-variable storage of heat from point to point through a wall or roof. The cyclic variation of outdoor conditions produces a related cyclic variation of tem perature and heat flow throughout each structural section exposed to the weather. The cyclic variations undergo a progressive shift in phase and decrease in amplitude in going through a wall with constant conditions maintained in the indoor space. '- By a shift in phase is meant that as the cyclic temperature wave passes through the wall, the time of occurrence of the maximum temperature at any point shifts farther and farther behind the time of the outer-surface maximum for successive positions through the wall. The resultant time lag between the outer-surface and inner-surface maximum temperatures is important, for it may be the determining factor in fixing the time of'the maximum cooling load. By a decrease in amplitude is meant that as the cyclic temperature wave . Cooling Load 275 passes through the wall, the difference between the maximum temperature of a cycle and the mean temperature of the cycle, which is the amplitude; of the wave by definition, decreases progressively as the wave passes through the wall. The magnitude of the temperature amplitude at the inner wall surface is necessary for the determination of the instantaneous rate of heat transfer to the indoor space. ., Practical design data for periodic heat flow comprise a meads of deter mining the time lag and amplitude decrement for different wall, construc tions; and any given outdoor cycle of sol-air temperature. Both analytical and experimental studies have been made on this problem.11 While the analytical solution has been written, it is far too detailed for direct use in rapid practical work; and the extensive numerical work required to estab lish a basis for simplified calculations has been only partially completed. The method reported by Mackey and Wright11 will be adopted as the basis for the design procedure recommended here. Homogeneous Walls or Roofs, Constant Indoor Temperature For walls or roofs of a single, homogeneous material, the instantaneous rate of heat gain within an enclosure where the indoor air temperature is held constant is, approximately,. . j = U (tm -- ti) + X(7 (t,* -- O Btu per (hour) (square foot) (5) where lm = 24-hr average sol-air temperature for the particular value of --, Fah- ' ' fero renheit degrees. X = amplitude decrement factor, a variable that depends upon the thickness material, and orientation of the wall or roof; see Table 10 for values.' The , amplitude decrement factor X as used in this chapter is equivalent to /1.65 X X\ ------ J as defined by Mackey and Wright,11 and also used by Stewart.1* te* = sol-air temperature at a time earlier than the time for which the heat gain is being found by an amount that is equal to the time lag of the wall or roof, Fahrenheit degrees; see Table 10 for values of time.lag. V -- overall coefficient of heat transfer of the wall or roof, Btu per (hour) (square foot) (Fahrenheit degree), u= 1 fcri .1 1 1L 1.65+4 + ft 1 0.856 , +7k h thickness of building material, inches. . k = thermal conductivity of building material, Btu per (hour) (square foot) (Fahrenheit degree per inch). . feei = unit indoor surface conductance (radiation and convection combined), Btu per (hour) (square foot) (Fahrenheit degree). /cro = unit outdoor surface conductance (radiation and convection combined), Btu per (hour) (square foot) (Fahrenheit degree). The time at which the maximum occurs in the rate of heat entry into the outside surface of walls or roofs is taken as the time at which the peak point occurs in the sol-air temperature cycle (mean sun time is used in the sol-air cycles). The corresponding maximum rate of heat entry follows from Equation 5 with te* being the maximum temperature of the sol-air cycle. The time of maximum heat gain to the room is obtained by adding the 276 CHAPTER 12 1952 Guide time lag to the time of maximum sol-air temperature (from Table 9) for the particular wall or roof. . ' ' " ; The magnitude of the. second term in Equation 5 relative to the first term indicates the relative.portion of the structural heat' in-flow assignable to periodic heat flow. The periodic term is continually passing through a cyclic variation from zero to a. positive maximum, to zero, to a negative maximum, to zero again and so on over each 24-hour cycle. Surfaces with Table 10. Pbbiodic Heat Flow Data fob Homogeneous Walls ob Roofs Material Thicknebs, In. - Over-all Co KmCIENT, Btu per (hr) (sq n)F) Thermal Resist^ ANCE OP (hb) (bq rr) (#F)/Bru L k Tins Lao. Hr. Factor, X, in Equation 5 Horisorital and North East South West Stone 8 0.67 12 0.55 16 . 0.47 24 0.86 0.64 0.96 . 1.281 1.92 - 5.58.0 10.5 15.5 0.51 0.28 0.17 0.06- 0.86 0.19 0.10 . 0.03 ` 0.48 0.26 0.15 0.05 0.42 0.22 0.13 - 0.04 . Solid Concrete ' Common Brick Face Brick Wood ' Insulating Board 2 4 6 8 12 16 . 4 8 12 16 4 H 1 2 . M . 1. 2 4 6 0.98 0.84 0.74 ` 0.66 0.54 0.46 r 0.60 0.41 0.31 , 0.25 . 0.77 0.68 0.48 0.30 6.42 0.26 0.14 0.08 0.05 0.17 0.33 0.50 0.67 1.00 0.80 1.60 2.40 3.20. 0.44 0.62 1.25 5 2.50 1.51 3.03 6.05 12.1 18.2 1.1 .2.5 3.8 5.1 . 7.8 10.2 2.3 5.5 8.5 12.0 . 2.4 0.17 0.45 . 0.08 0.23 . 0.77 2.7 . 5.0 0.93 0.79 0.61 0.49 0.29 0.17 ' . 0.83 0.51 0.26 0.13 0.81 1.0 1.0 0.98 1.0 1.0 1.0 0.83 0.64 0.87 0.68 0.46 0.33 0.17 0.09 0.75 . 0.39 0.17 0.08 0.70 1.0 0.99 0.91 1.0 1.0 1.0 0.74 0.49 0.92 0.78 0.58 0.46 0.26 0.15 0.81 0.49 0.25 0.12 . 0.78 1.0 0.99 0;96 1.0 1.0 . 1.0 0.81 0.61 0.89 0.72 0.51 0.39 0.22 0;12 0.78 0.44 0.21 0.10 0.74 1.0 0.99 0.94 1.0 1.0 1.0 0.76 0.55 * Based upon an outdoor.surface conductance .of 4.0 and an indoor surface conductance of 1.85;Btu per (hour) (square foot) (Fahrenheit degree). ` different exposures pass through these cycles with maximum points at dif ferent times of day. .... An example in the use of Tables 9 and 10 follows: Example 7.- . Find the instantaneous rate of heat gain through an 8 in. west wall of common brick (at = 0.7, /ero -- 4.0) located at 40 deg north latitude at 9:30 p.m. sun time. The indoor air temperature is constant at 80 F.. Use sol-air data for an industrial atmosphere. . . Solution: From Table 10,. U -- 0.41, the time lag is 5.5 hr, and X = 0.44. By linear interpolation on the basis of aJfao in Table 9, ` U = 83.1 + U.J5 (92-9 - 83.1) = 90;0F. The design sol-air temperature at a time earlier than 9:30 p.m. by the .time lag (at 4:00 p.m.) is, by interpolation, from Table 9, . . ' U' " 94 + jrir (13.7 - 94) = 124.1 F. Cooling. Load 27.7. From Equation 5, the instantaneous design rate of heat gain is , J- = 0.41[(90.0 - 80) + 6.44(124.1 90.0)] = 10.3 Btu per (hr) (sq ft). From Table 10, the time lag is 5.5 hr. From Table 9,' the time of maximum rate of.heat entry for a west wall is 4:00 pm. plus 5.5 hr or 9:30 p.m. (this is sun time). The coniputed rate is therefore the maximum rate. . . -. :- -- . - Composite . Walls or Roofs, Constant Indoor Temperature; ' ' A> composite wall or roof is made up of'two or more layers of different materials. 'Since'the analytical solution for this type of construction has not been reduced to simple and practical terms, it is necessary at present Fig. 2. Approximate Value of the Amplitude Decrement Factor X .. . fob Use in Equation 5 to utilize approximate procedures. In accord with the results of com parative calculations, the following procedures are suggested.11 To find a time lag for a composite construction: a. Find the time lag for each layer from Table 10. . I b. Add the individual time lags, recognizing that-this sum will always be less than the true time lag for the actual composite wall. . . c. To the sum from (b), add an arbitrary additional lag of ) to 1 hr to obtain the estimated lag for the actual construction. For two-layer and light construction walls, the f-hr value will be suitable while, for walls of three or more layers, or very heavy construction, the 1-hr value, is preferred. For intermediate conditions, indi vidual judgment is the only guide. (Computed time lags should not be considered, to be accurate closer than to about the nearest hour by this method.) To find the amplitude decrement factor, X, for composite construction: Having determined the time lag and the orientation, use Fig. 2. (Note also that the factor X for a. composite construction should never exceed the product of the factors for the individual layers.) ' One valuable result of the analytical studies made to date on composite waffs has been the demonstration of the effect of the order of the materials. Other factors remaining the same, the use of the material of lower density 278 CHAPTER 12 1952 Guide on the weather side will increase the time lag and decrease the instan taneous maximum rate of heat gain. Two examples are given to show how to estimate, roughly, the instan taneous rate of heat gain through sunlit composite walls or. roofs.. - Example 8: Estimate the maximum instantaneous design rate of heat gain from a horizontal roof in a location having an industrial type of atmosphere. The roof is made up of black, built-up roofing on the weather side (a = 1, U = 4,thermal resistance = 0.28), 1 in. of insulating board, and 4 in. of concrete with no ceiling. The temperature of the indoor air is 80 F. ' ^ Solution: The overall coefficient of heat transfer for this construction is: IT = ----1---------------------------------------------------------------------------- = 0.22 Btu per (hour) (square foot) (F deg) u 0.25 + 0.28 + 3.03 +.0.33 + 0.61 .. ... If the time lag of the built-up roofing be ignored, the sum of the time lags of the individual layers is, from Table 10, (0.23 + 2.5) or 2.73 hr. ~ Actually, the time lag will be between 0.5 hr and 1.0 hr greater than this, so assume a time lag of 3.5 hr. From Table 10, the homogeneous concrete roof having a time lag of 3.5 hr would have a value of X of about 0.65; use this .value for the composite roof. From Fig. 2, X is approximately 0.65. With values of U and .* found from Table 9, as in previous examples, use Equation 5 and find the maximum design instantaneous rale of heat gain as: 1 = o.22[(103.4 - 80) + 0.65(151 - 103.4)1 = 11.9 Btu per (hr) (sq ft). A . The maximum instantaneous rate of heat gain from this roof would occur at about 4:30 p.m.,-sun time. Example 9: Estimate the maximum instantaneous design rate of heat gain on August 1 from a south wall in a location at 40 deg north latitude having a clear at mosphere. The wall consists of 4 in. of face brick (a, = 0.7; / = 4.0),.4 in. of common brick, furred, with an air space (thermal resistance = 0.75), and finished on the inside with | in. of plaster on metal lath (thermal resistance -- 0.23); the tem perature of the indoor air is constant at 75 F. _ Solution: The overall coefficient of heat transfer for this construction is: U = 0.25 + 0.44 1__________________=__0_._3_2_B__tu__p_e_r__(h_r) + 0.80 + 0.75 + 0.23 + 0.61 (sq ft) (F deg). From Table 10, the sum of the time lags for the face brick and the common brick is (2.4 + 2.3) or 4.7 hr. The.actual time lag will be slightly greater than this, and a value of 5.5 hr will be assumed. ' From Fig. 2, X is approximately 0.45. By interpolation in Table 9, U = 89.5 F, and t* = 115.4 F. From Equation 5 the maximum instantaneous design rate of heat gain is: .. 1 = 0.321(89.5 - 75) + 0.45(115.4 - 89.5)] = 8.4 Btu per (hr) (sqft). A" . ., The time of this heat gain is about 6:30 p.m., sun time: ` Those concerned with a further study of the details of cooling-load estimates in particular relation to periodic heat flow will find much of value and interest in the reports of experimental studies of these problems.8, e 111 l8, l4, 16 PRACTICAL TABLES FOR CALCULATING SOLAR HEAT GAIN THROUGH WALLS AND ROOFS Use of Equivalent Temperature Differentials . The preceding paragraphs have explained the principles and methods used in estimating solar heat gain- by use of sol-air temperature. This method is rather tedious and is not convenient for every-day use. Some Cooling Load 279 new practical tables12 have therefore been' `developed using - the basic method reported by Mackey and Wright.11 These new tables utilize equivalent temperature differentials which may be multiplied by the overall heat transmission coefficient U to give directly the total heat transmission, Btu per square foot, from solar radiation and from temperature difference between outside and room air. These tables were prepared from sol-air data, as shown in Table 11, which Table 11. Summer Design Sol-Aib Temperatures Used for Tables . 12 and 13 q Mean Sun Time 4 S - Uol Air Temperature Fahrenheit Degrees Auy Sur Horn. North face1* ` East South West . Ratio*: -j-- /eo 12 Midnight . 1AM .2 3 4 5 6 7 8 9 10 11 12 Noon 1PM 2 3 4 5 6 7 8 9 , 10 11 24 Hr Avg tm 0 0.225 0 0.225 0.125 0.225 0.125 0.225 0.125 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 74 74 74 74 74 74 74 74 74 74 74 74 75 80 74 74 74 74 74 76 74 110 93 74 74 74 74 75 91 75 123 100 75 75 75 75 77 106 77 126 103 82 78 77 77 80 119 80 125 104 93 86 80 80 83 129 83 117 100 102 93 83 83 87 137 87 108 - 96 110 99 89 87 90 142 90 ' 92 92 114 104 98 92 93 144 93 93 93 115 105 110 102 94 140 94 95 94 111 104 124 111 95 132 95 95 95 104 100 135 119 94 120 94 93 107 93 91 96 91 .87 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 85. 85 85 83 83 83 81. 81 81 79 79 79 85 85 85 85. . 85 85 83 83 83 83 83 83 81 81 81 81 81 81 79 79 79 79 79 79 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. fco = unit convective conductance = 4.0 Btu per (hr) (F deg). -. ' b values in this column are magnitudes of to, the outdoor air temperature. are approximately the same as data for an industrial atmosphere in Table 9. It is suggested that Tables 12 and 13 be used for general estimating purpose. These analytical procedures, as well as those using Tables 9 and 10 pre sented here, yield generally higher rates of heat gain than reported for Pitts burgh in early A.S.H.V.E. experimental studies. Current authoritative opinion indicates a preference for analytical calculations. ` . '280 CHAPTER 12 1952 Guide Table 12. Total Equivalent Temperature'Differentials for Calculating : Heat Gain Through Sunlit and Shaded Roofs _Sun Time ' Description of Roof Construction*. A.M. . P.M. ' 8 10 12 2 4 6 8 10 12 " ' - ' Light Construction Roofs-- Exposed to Sun 1" Woodb or 1' Woodb + 1" or 2" Insulation . 12 38 54 62 50 26 10 4 0 Medium Construction Roofs--Exposed to Sun 2" Concrete or . . 2f Concrete + 1' or 2" Insulation or 2" Woodb ; 6 30 48 58 50 32 14 6 2 2' Gypsum or 2' Gypsum + 1' Insulation l* Woodb or 2" Woodb or + 4' Rock Wool 2" Concrete or in Furred Ceiling 2Gypsum : 0 20 40 52 54 42 20 10 6 4* Concrete or . 4" Concrete with 2" Insulation , - . 0 20 38 50 52 40 22 12 .6 Heavy Construction Roofs--Exposed to Sun 6" Concrete .. ': 6* Concrete -b 2* Insulation 4 6 24 38 46 44 32 18 12 6 6 20 34: 42 44 34 20 .14 Roofs Covered with Water--Exposed to Sun Light Construction Roof with 1* Water Heavy Construction Roof with 1' Water Any Roof with 6* Water 0 . 4 16 :22 18 14 10 2 -2 -2 -4 10 14 16 14 10 -2 0 0 . 6 10 10 '. 8 4 0 6 0 , `' Roofs with Roof Sprats-- Exposed to Sun Light Construction 1 Heavy Construction . `. : 0 4 12 18 16 14 10 '2 0 ; -2 -2 2 8 12 14 12 10 6 J . ' Light Construction Medium Construction Heavy Construction Boops in Shade 1 ;- :' . ! --4 0 -4 --2 --2 -2 6 12 14 12 8 '2 2 8: 12 12 10 6 0 4 8 10 10 8 0 2 4 ? Includes 1 in. felt roofing with or without slag. May also be used for shingle roof. ^Nominal thickness of the wood. ; ' : . . NOTES FOR TABLE 12 [Total heat transmission from solar' n__ __.. J radiation and temperature difference Explanation, jbetween outside and room air. Btu . * (per (hr) (sq ft) of roof area . -- , - Heat transmission Equivalent temperature differential from above Av coefficient forsummer Btu per (hr) tabl.e .... . . (sq ft) (F de. g. ) 1. Source. Calculated by Mackey and Wright method (see reference list) and adjusted after siudying ASHVE original test data. Estimated for July in 40 deg north latitude. (For sol-air temperatures used in calculations see Table 11.) For typical design day where the maximum outdoor temperature is 95 F and minimum temperature at night is approximately. 75 F (daily range-of. temperature, 20.F) mean 24 hr tem perature 84 F for a room temperature of 80 F. All roofs have been assumed a dark color which absorbs 90 percent.of 'solar radiation, and reflects only 10 percent. ,: -. ' .. - - * . 2. Application. These values may be used for all normal air conditioning estimates; usually without correction, in latitude 0 deg to 50 deg north or south when the load is calculated for the hottest weather.' Note 5 explains how 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 the area of the roof, the area projected on a horizontal plane. . - . .. 4. Attics. If the ceiling is insulated and if a fan is used in the attic for positive ventilation, the total tem perature differential for a roof exposed to the sun may be decreased 25 percent. ' '- Cooling Load 281 v 5; Corrections. .For temperature difference when outdoor. maximuip'design.temperature.mSnus^rbom is-dif ferent from IS 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. ..... . . ... For outdoor daily range of temperature other than SO deg: If the daily range of temperature is less than 20 deg, add 1 de$ for every 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 -f 4 deg at all hours of the day. ' ......... . flight Colors. . Credit should not be taken for light colored roofs except where the permanence ofthe-light color is established by experience, as in rural areas or where there-is little smoke. When the exterior surface roof exposed to the sun is a light color, such as white or aluminum-(which absorb approximately 50-percent arid'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 tn othOr months. The table values of tem perature differentials will be approxi mately correct for a roof in the following months: ' , North Latitude t Latitude (deg) - Months . .- ' 6 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 Latitude (deg) Months 0 All Months ' 10 All Months .- 20 All Months except May, June, July 30 Sept, Oct. Nov. Dec, Jan. Feb. Mar 40 Oct, Nov, Dec, Jan, Feb . 50 Nov, Dec, Jan For other months, the.total temperature differential (t*) may be approximated by'the use of the following formula: ' . ' . . . - .' , " - - tx = te -f- (< -- t) ... ir - where t -- temperature differential for the same wall in shade for desired time of day; obtained from Table 12. , ; ly = 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). . / = same as ly except use the maximum value for flat skylight, for month, and latitude desired for t* tv -- temperature differential for particular roof exposed to sun for the desired time of day from Table 12.' . ' .' . (Note that this 'makes adjustment only-for solar radiation and that there may he additional correction for out door temperature.) ._ ' . " Tables 12. and 13 are based on an equation re-arranged from Equation 5 to read: - . , = 4 = Ultu, + X ((.* - tn) "*!] . . A .. r.......................~V (6) -. Let L + X(<o* -- tm) = Ip, a net equivalent outdoor temperature for com bined periodic and mean heat flow. Magnitudes of <P will vary cyclically with time. Then, :: -- j = V{tp-ti) .................... (7) which is a simple form analogous to the steady state equations of Chapters 5 and 9. 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 12 and 13 were developed by using an outside surface conductance of 4.0 and an inside film conductance of 1.65 Btu (hr);(sq ft) (E deg): A reduction was made in the temperature differentials for roofs amounting to some 20 percent of solar radiation as' explained by Stewart.12 . This was to compensate for several factors, one of which is the radiant heat lost, to the 282 CHAPTER 12 1952 Guide Table 13. Total Equivalent Temperatube Differentials for Calculating , :' Heat Gain Through Sunlit and Shaded Walls Sun Time * Nobth Latitude . . Wall .... Facing .3 A.M. P.M. . .' 10 12 2 ` 6 6 10 Exterior oolor of Wal --D - dark, L =* light 12 South ' -Latitude Wall . Facing . D LD D D LD LD D D D Frame '- NE ' 22 10 24 12 14 10 12 10 14 14 14 14 10 10 6 4 2 2 ' SE E 30 14 30 18 32 10 12 12 14 14 14 14 10 10 6 6 2 .2 E SE 13 6 20 10 28 18 24 16 16 14 14 14 10 10 6 4 2 2 NE 8 -4 -4 4 0 22 12 30 20 26 20 16 14 10 10 6 6 2 2 N SW. -4 -4 0 -2 0 4 26 22 40 28 42 28 24 20 6 4 2 2 NW W -4 -4 0 0 0 0 20 12 40 28 48 34 22 22 8 8 2 2 W NW -4 -4 0 -2 0 4 12 10 24 20 40 26 34 24 6 4 2 2 SW N (Shade) - --4 -4 -2 -2 4 4 10 10 14 14 12 12 8 8 4 4 0 0 . S (Shade) 4 In . Brick OB Stone Veneer + Frame NE -2 -4 24 12 20 10 10 6 12 10 14 14 12 12 10 10 6 4 - SE' ` E 2 0 30 14 31 17 14 14 12 12 14 14 12 12 10 8 6 6 E SE 2 --2 20 10 28 10 26 16 18 14 14 14 12 12 10 8 6 6 NE S -4 -4 -2 -2 12 0 24 16 26 18 20 16 12 12 8 8 4 4 N SW ' 0 -2 0 -2 2 2 12 8 32 22 36 26 34 24 10 8 6 6 NW ' W 0 -2 0 0 4 2 10 8 26 18 40 28 42 28 16 14 6 6 W NW -4 -4 -2 -2 2 2 8 0 12 12 30 22 34 24 12 10 6 6 SW N (Shade) -4 -4 -2 -2 0 0 6 6 10 10 12 12 12 12 8 8 4 4 8 (Shade) 8 In. Hollow Tile OB 8 In. Cinder Block NE E SE 8. SWw NW . N (Shade) 0 0 0 0 20 10 16 10 10 6 12 10 14 12 12 10 8 8 SE 4 2 12 4 24 12 26 14 20 12 .12 10 14 12 14 10 10 8 E 2 0 2 0 16 8 20 12 20 14 14 12 14 12 12 10 8 6 NE 0 0 0 0 . 2 0 12 6 .24 14 26 16 20 14 12 10 8 6 . N 202020 4 2 42 42 000020 -2 -2 -2 -2 -2 -2 6 4 12 10 26 18 30 20 26 18 8 6 NW 6 4 10 8 18 14 30 22 32 22 16 14 W 4 2 8 6 12 10 22 18 30 22 10 8 SW . 0 0 6 6 10 10 10 10 10 10 6 6 S (Shade) 8 In. Brick or 12 In. Hollow Tile or 12 In. Cinder Block NE E SE 8 SW W NW N (Shade) 222 868 840 424 8 4 0 840 222 000 . 2 10 0 14 40 24 2 16 8 14 8 10 6 10 8 10 10 10 8 8 18 10 18 10 14 8 14 10 14 10 12 10 4 14 10 18 12 16 12 12 10 12 10 12 10 2 4 2 10 6 16 10 16 12 12 10 10 8 4 0 4 8 4 10 6 12 8 20 12 24 16 20 14 4 0 6 8 6 10 6 14 8 20 16 24 16 24 16 2 2 2 4 2 6 4 8 6 10 8 16 14 18 14 0 0 0 0 0 2 ,2 6 6 8 8 8 8 6 6 . 12 In. Brick ' . SE E .. . NE N NW ' W SW S (Shade) . NE E SE S SW W NW N (Shade) 8 6 8 0 8 4 8 4 10 4 12 6 12 6 10 6 10 6 SE . 12 8 12 8 12 8 10 6 12 8 14 10 14 10 14 8 14 8 E 10 6 10 0 10 6 10 6 10 G 12 8 14 10 14 10 12 8 NE 8 6 8 6 0 4 6 4 6 4 8 4 10 6 12 8 12 8 N 10 6 10 0 10 0 10 6 10 6 10 8 10 8 12 8 14 10 NW 12 8 12 8 12 8 10 6 10 6 10 6 10 0 12 8 16 10 W . 8 6 8 0 8 4 8 4 8 4 8 4 8 6 10 6 10 6 SW 4 4 2 2 2 2 2 2 2 2 ' 2 2 2 2 4 4 6 6 S (Shade) 8 In. Concrete or Stone OR 6 In. or 8 In. Concrete Block NE E SE S 8W ' W NW N (Shade) 4 2 4 0 10 8 14 8 10 6 12 8 12 10 10 8 8 6 SE 6 4 14 8 24 12 24 12 18 10 14 10 14 10 12 10 10 a E 6 2 0 4 10 10 18 12 18 12 14 12 12 10 12 10 10 8 NE 2 1 2 1 4 1 12 6 16 12 18 12 14 12 10 8 8 6 N 6 2 4 2 0 2 8 4 14 10 22 16 24 16 22 16 10 8 ' NW 6 4 0 4 6 4 8 -.c 12 t -2C lA 28 18 2f If 14 10 W N 4 2 4 0 4 2 A A e f li 1C 2C 14 22 1C f 6 .SW 0 0 0. 0 0 0 2 2 4 4 6 6 8 8 6 6 4 4 S (Shade) Cooling Load 283 Table 13. Total Equivalent Temperature Differentials fob Calculating Heat Gain Through Sunlit and Shaded Walls--Concluded. Sun Time North . Wall . NE E SE S . SW W NW . N (Shade) A.M. P.M. 8 10 12 i - l 1 10 12 Exterior color of Wall --D -- dark, L = light D D LD L D L D L D L LDL D 12 In. Concrete or Stone L 6 .4 10 6 84 6 4' 84 10 8 64 00 6 8 8 4 8 8 6 0 26 6 10 46 24 46 68 26 00 2 14 8 14 8 10 8 10 8 12 10 10 8 6 18 10 18 12 16 10 12 10 14 10 14 10 4 14 8 16 10 16 10 14 10 12 10 12 10 2 4 2 10 6 14 10 16 12 ,14 10 10 8 4 6 4 8 6 10 8 18 14 20 14 18 12 6 10 6 10 6 12 8 16 10 24 14 22 14 2 6 4 6 4 8 6 10 8 18 12 20 14 0 0022 44 668866 South Latitude Wall Facing SE E NE N ' NW W. SW S (Shade) NOTES FOR TABLE 13 Explanation: Total heat transmission from solar radiation and temperature difference between outside and room air, Btu per (hr) (sq ft wall area) Equivalent temperature differential from above table Heat a transmission coefficient for wall, Btu per (hr) (sq ft) (F deg) NOTES: . . 1. SOURCE. Same as Table 12: 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, m which case it may be desirable to make correction to the temperature differentials shown. Thesolar intensity on all walls other than east and west varies consi derably 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 daily 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 range. For example, the daily range in Miami, Florida is 12 deg, or 8 deg less than 20 deg; therefore, the dor-.- rection is +4 deg. ' Color of exterior surface of wall. Use temperature differentials for light walls only where the permanence of the light wall is established by experience. For cream colors use the values for light walls. For medium colors interpolate hlf way between the dark and light values. Medium colors are medium blue, medium green, bright red, light brown, unpainted wood, natural color concrete, etc. Dark blue, red, brown, green, etc., are considered dark colors. ' " . Forlalitudes other than 40 deg north; and in other months. These table values will be approximately correct for 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 noon) the temperature differential for either a south or north wall will be approximately the same as a north,, or shade wall. The temperature differential ((*) for any wall facing, and for any latitude for any month may be approximated as follows: ` ' (i a ( + yj X (lw -- /) : where = temperature differential for the same wall in shade for desired time of day; obtained from Table 13. . , h -- 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). It = same as Ii except use the maximum value for wall facing, for month, and latitude desired for tx.. tw = temperature differential for particular wall facing, for the desired time of day from above table. (Note that this makes adjustment only /or solar radiation, and that there may be additional correction ' for outdoor temperature.) . - 4. POR INSULATED WALLS use same temperature differentials as used for uninsulated walls. 284. CHAPTER 12' 1952 Guide -Table 14. ~ USummer Coefficients of Heat. Transmission of Flat Roofs Covered With Built-Up Roofing* > ~-Btu-per (hour) (square foot) (F deg difference between the air on the two sides) '` 1 ~----ft's------------------------ ------------------------ Insulation on Top op Deck " {Covered With Built-Up Roofing) TtpE'.oF; Roof Deck Ceiling not shown ' Thickness of Roof Deck (Inches) . . NoCeiling-- , . Underside of Roof . ' Exposed . . No' In sula' tion Insulating' Board? Thickness, In. i 1' u 2 Furred Ceiling with Air Space, Metal Lath . . and Plaster A No In-, sula- tion Insulating Boardd .Thickness, In. i u 2' Flat Metal -Roof Deck . -4 Ply . Felt : ' Roof ; Ditto" ' + } in. 81ag. 0.73 0.35 0.23 0.17 0:13 0.40 0.25 0.18 0.14 0.12 0.54 0.30 0.20 0.16 0.13 0.34 0.22 0.16 0.13 0.11 Precast Cement Tile ' ' ----- PI 4 Ply Felt Roof ; it Ditto .4* in. Slag H ' .1 .0.67 0.33 0.22 0.17 0.13 0.38 0.24 0.18 0.14 0.12 0.50 0.28 0.20 0.15 0.12 0.32 0.21 0.17 0.13 0.11 Concrete 4 Ply 2 0.65 Felt 4 0.59 - ` Roof . - - 6 0.54 . isfiw. r^s3?8 Ditto - .. . 2 .. . 0.49 f .- 4... 0.46 ~7 --J + 4 in. Slkg 6 0.42 0.33 0.22 0.16 0.13 0.37 0.31 0.21 0.16 0.13 0.36 0.30 0.20 0.16 0.13 0.33 0.28 0.20 0.15 .0.12 0.31 0.27 0.19 0.15 0.12 0.30 0.26 0.19 0.14 0.12 0:29 0.24 0.18 0.14 0.12 0.23 0.17 0.13 0.12 0.22 0.17 0.13 0.11 0.21 0.16 0.13 0.11 0.21 0.16 0.13 0.11 0.20 0.16 0.13 0.10 Gypsum and Wood Fiberb on 1* Gypsum Board ------- N------------ ^ e---^ 4 Ply Felt Roof Ditto + i m. Slag. 24' 31 H 31 0.34 0.23 0.17 6.13 0.12 6.25 0.18 0.14 0.12 0.097 0.28- 0.20 0.15 0.12 0.11 0.21 0.16 0.13 0.11 0.094 0.29 0.20 0.16 0.13 0.11 0.22 0.16 0.13 0.11 0.093 0.25 0.18 0.14 0.12 0.10 0.19 0.15 0.13 0.10 0.090 Wood --__ __ 4 Ply Felt Roof ! 0.43 0.26 6.19 0.15 0.12 0.'29 0.^0 6:15 0.13 0:11 u 0.33 0.22 0.17 0.13 0.11 0.24 0.18 0.14 0.12 0.097 2 -0:29 0.20 0,16 0.13 0.11 0.22 0,16 .0.13 0.11 0.094 3 0.22 0.16 043 .0.11 0.09 0.17 0.13 0.12 0.10 0.085 1 Ditto H 4* 4 in. Slag 2 3 0.35 0.29 0.26 0.20 0^23 0.17 0.14 0.11 0.25 0.20 0.15 0.12 0.10 0.21 0.19 0.14 0.12 0.10 0.20 0.15 0.12 0.10 0.09 -0.16 0.18 0.14 0.12 0.10 0.17 0.13 0.11 0.093 0.15 0.13 0.10 0.090 0.13 0.11 0.09 0.081 The summer coefficients are considered temporary, and have been calculated 'with an outdoor wind velocity of 8 mph. For summer an inside surface conductance of 1.2 ha* been used instead of the regular 1.65 value. In all of these roofs a 4 ply felt roof has been assumed I in. thick, thermal conductivity = 1.33. Fitch and slag have been assumed as an additional thickness of 1 in. which has been assigned thermal con ductivity = 1.0. In both cases thermal conductivity refers to one.inch thickness. . b 87i percent gypsum, 12i percent wood fiber. Thickness indicated includes J in. gypsum board. This is a poured roof. c Nominal thickness of wood is specified, but actual thickness was used in calculations.' - - d If corkboard insulation is used, the coefficient U may be decreased 10 percent. sky which is not included in the Mackey and Wright method. The tem perature differentials for roofs were based on an inside surface conductance of 1.65 because the charts prepared by Mackey and .Wright1* used this Cooling Load '285 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 temperature differential would be changed very little even if a value 1.20 were used instead of 1.65. But to obtain the heat flovy .rates through roofs, more accurate values will be obtained if the overall heat, trans mission coefficient is calculated using 1.2 as the inside film conductance of s heat transfer in summer. The roof coefficients of transmission for summer shown in Table 14 are based bn surface conductances /cro of 4.0 for an outside roof surface and 1.20 for ah 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 inside 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. ' ' ` j\ .. . ; 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 T:65,-it is recommended that the overall coefficient Ujfor walls, be taken directly from the tables in Chaptei! 9iirwhich 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 areapparent from Examples lO to 12. 1. The total sensible heat flow is obtained by multiplying the overall heat trans mission coefficient, U, and the equivalent temperature .differential indicated in Tables 12 and 13. . 2. The temperature differentials listed for few representative types of con struction maybe used on all classes of walls and roofs, even though the overall heat transmission coefficient is-different, provided the structure has thermal and.physical properties similar to one of those listed in Tables 12 and 13. ... . 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 10: Given: A roof is constructed of 6 in. of stone concrete with 2 in. of insulating board and tar felt roofing jf 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 80 F. ' Solution: From .Table-12 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 mission coefficient for summer is taken from,Table 14 and is found to be 0.13. The heat flow rate equals 34 X 0.13 = 4.42 Btu per (hr) (sq ft). Example 11: For the conditions of ExampldiO, find;the rate of heat flow into build ing at 2:00 p.m. during July for design temperatures of 105 F (outdoor) and 78 F (in door). Daily range of temperature 30 deg, i.e., outdoor temperature minimum .of 75 F which,occurs.at 4;00;or 5:00 a.m.; this.being 30 deg less than the maximum. ; -7 Solution.:. Make.correction in equivalent. temperature differential in accordance ` with Note 5 in Table 12 as follows: - - . . ... v The correction' for 27 deg design temperature difference is (27 -- 15) = + 12. 286 CHAPTER 12 1952 Guide _. . / jq_20\ The correction for 30`deg daily- range is (-------- ^--) = -- 5. Net total correction is + 12 -- 5 = + 7. . .. .. The heat flow rate at 2:00 p.m. therefore is (34 + 7) X 0.13 .= 5.32 Btu per (hr) (sq ft). ----- ' A' method of determining heat flow rales, when structure is not given in Tables 12 or 13, is illustrated in Example 12. . Example IS: 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 J 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. ...... V------V----- if- SUN (WAVE LENGTHS UNCHANGO^ JRANSMITTCD INDOOR RADIATION (Wave lengths unchanged) OUTDOOR CONVECTION to>Vt.< V" THERMAL CAPACITANCE OP CLASS INCIDENT INDOOR RADIATION REELECTED l INDOOR - RADIATION INDOOR CONVECTION ~ V<u V>^ s CHITTED OUTDOOR RADIATION ^DIFFERENT DISTRIBUTION If*--it*--Jf- EMITTED INDOOR RADIATION (DIFFERENT DISTRIBUTION * OF ENERGY VS.WAVE LENGTH THEN TRANSMITTED) ' m OUTDOOR AIR TEMPERATURE too OUTDOOR CLASS - SURFACE TEMPERATURE it mm INDOOR AIR .TEMPERATURE INDOOR GLASS SURFACE TEMPERATURE . . Fig. 3. Instantaneous Heat-Balance Conditions on a Glass Section . . . Solution: For the purpose of selecting the equivalent temperature differentialt this construction is assumed to be equal approximately to ah 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 12. Calculate the overall heat transmission coefficient U of the roof as follows: ' 1 U= : 0.33. --1--- 1---4--- 1---4----j--0--.3--7-5-- ^0-.-5--0-- (_ --1 \2 12 4.97 1.33 1.00 4.0 'Die heat flow rate is then 38 X 0.33 equals 12.5 Btu per (hr) (sq ft). TABLES FOR CALCULATING SQLAR 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. 3. The net heat Cooling Load 287 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 through glass section _ IPisToralanrsrmadititaetdio, n J"1I ["Heat flow by convective and radiative exchanges at Lthe indoor surface . (7a) The second term of the right side of Equation 7a can also be expressed by a heat balance equation as follows: . [Heat flow by convective-] ["Absorbed-] rRadiative exchanges be- "1 and radiative exchanges I = solar . I 1 tween outer surface of glass I at the indoor surface J Lradiation J Land outdoor surroundings J ["Convective exchanges "| THeat storage-] between outer surface of I within the I (7b) Lglass and outdoor air J Lglass sectionJ Equations 7a and 7b can be combined and expressed in symbolic terms by Equation 7c. Tabular values of the two bracketed terms of Equation 7a are presented later in this section for various types of glass for specific design conditions. (q/A) where [td/d + rd/d] + [otd/d + ad/d + e,o-- tgoRgo -- fco (f,o -- O -- jSG, Btu per (hr) (sq ft) (7c) (q/A) = instantaneous rate of heat flow, Btu per (hour) (square foot). .. rD, rd = transmittance of glass for direct and diffuse solar radiation, respectively. Id, /d = incident direct and diffuse solar radiation, respectively, Btu per (hour) (square foot). .. aD, ad = absorptance of glass for direct and'diffuse solar radiation, respectively.. tgo = emissivity of glass at temperature l<o. . : : '. Rm = low temperature radiant energy falling on glass from outdoor surround ings, Btu per (hour)(square foot). . Rgo ' - low temperature radiant energy emitted by a surface with emissivity equal to 1.0 at temperature /,,,. fa, = outdoor convective conductance, Btu per (hour) (square foot) (Fahren heit degree). tga = temperature of outdoor surface of glass, Fahrenheit degrees. to = temperature of outdoor air, Fahrenheit degrees. '. S = rate at which glass stores energy, Btu per (hour)(square foot). Transmissivity and absorptivity vary with both wave length of the incident radiation and incident angle. Values of r and a for a single sheet of the average ordinary drawn window glass are given in Table 15 for a standard distribution, of solar energy.* Values for two air-spaced sheets 288 CHAPTER 12 1952 Guide are also given. Normal incidence transmittance valuesfor some com monly-used types and combinations are given in Table. 18. ..Some yaria-: tion in these, values can be expected in. practice due to variations in manufacture and in solar .'energy distribution. ^However, a .change jn transmissivity causes an-approximately equal and `opposite, change.-in absorptivity. Hence, thei'total heat flow is not' greatly- altered. ` Ttaris-. mittance data for other types of glass, arid various patterns of 8-in- glass blrick are given in A.SJI.V.E. research papers.16'17 20 ... ` A . As stated earlier in this chapter,- present data as to the value , of Rl are inadequate, so for the present it is suggested that f,, be. increased to. include'radiation, and the term e^R. f&Rt. be disregarded. - It is not practicable to give values of S in this chapter. However, for ordinary glass, the value of & is small. .,, , Fig. 4 is a graphical solution, for single glass, of`Equation' 7b. Only Table 15. Tbanbmittances and Absobptances or Common Window Glass fob Dibect and Diffuse Solas Radiation ` ': Single Sheets ' . TWO AIB-SPACED SHEETS t Angle of Incidence, $, DEG '0 20 40 fiO 60 70 80 90 . ** 0.87 0.87 0.88 0.84 0.70 0.67 0.42 0.0 * 0.79 ftD ' D Outdoor Sheet Indoor Sheet -Fob Direct Radiation . . '' 0.05 .. 0.05 0.06 0.08 .. 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 0.08 0.07 ; 0.07 6;07 , 0.07 0.0 0.04 0.04 0.04 0.05 . 0.05 -0.05 : 0.05 0.05 S Fob Diffuse ob et Solab Radiation f. . : 0.06 0.68 0.07 0.05 absorbed solar radiation is considered, although low temperature radiation 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/oi as given by Equation-8, and an equivalent surface conductance for radiation fri as given by Equation 9. Indoor surfaces seen, by the glass, are.assumed to radiate as a.black body at room air temperature. ... : ' /ri = 0.162 [(^9)`:- (Mo?)4] / (9) where :! t,i = temperature of indoor surface of glass, Fahrenheit degrees, fi = temperature of indoor air, Fahrenheit degrees. . A more complete treatment of the problem is given in an A.S.H.V.E. research paper.18 . . . Example IS: Find the total heat gain at 10 a.m.'sun time for a single unshaded', sheet of common window glass in a wall facing 18 deg east of south on August 1 at; Cooling Load 289 50 deg' n'O'rth 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 9 min. From Example 4, Id = 152.0, Id = 26.6. By interpolation in Table 15, td is found to be 0.81, aD is 0.06; t& and d are 0.79 and 0.06, respectively. The heat gain due to transmitted solar radiation is (g/A), = 152.0 X 0.81 + 26.6 X 0.79 = 144.1 Btu per (hr)(sq ft). The heat gain by convection and radiation from the indoor surface is found from Fig. 4: . . from which t,, + f* = 83 + 0^6. (152-0 + 26,6) _ ^ ? y /eo 4 .. :. ; (g/A)a = 1U Btu per (hr)(sq ft). ' Fiq. 4. Convection and Radiation Heat Flow fob Vebtical: Single Glass From Equation 7a the total heat flow is (g/A) = 144.1 4- 11.5 = 155.6 Btu per (hr)(sq ft). ^ Design Tables for Flat Glass ' Tables 16 and.17 give design values of instantaneous rates of heat gainior 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 Hie solar, intensity values for a clear atmosphere as given in Table 5. Table 16 represents the first bracketed term of Equation 7a;.therefore, the values are dependent only upon values of 7 and t. Tabie.17 is the second term of Equation 7a, and is based upon a 75 F indoor temperature and a dry-bulb temperature cycle, with a 95 F maximum as tabulated. The total heat gain is the sum of the Table 16 and Table 17 values. In preparing Table 17, convection and radiation heat exchange were coinbined, and a' combined surface conductance of 4.0 used. Correctioris to be applied for 290 CHAPTER 12 1952. Guide 16. orTable ..Instantaneous Rates Heat Gain Due to Transmitted Direct orand Diffuse or Sky Solar Radiation by a Single Sheet Unshaded ; . Common Window Glass ;, ' For Clear Atmospheres and 18 Deg Declination, North (August 1) Note: For total instantaneous heat gain, add these values to the Table 17 values. soo Sun Time AM*** i . ` Instantaneous Heat Gain in Btu peb (he) (so ft) N- ' NE . E se -s sw W::. NW` Hobiz. 6 a.m. 6 p.m. 25 98 108 52 H7 5 23 155 190 no 84 16 148 205 136 S5 9 3 16 106 180 136 a 10 11 12 2 1 17 54 128 116 18 20 59 78 18 -19 19 35 55 55 17 10 10 10 10 71 14 13 13 13 137 21 15 15 15 195 34 17 16 16 241 45 19 18 . 18 267 49 35 19 19 276 5 a.m. 7 p.m. 3 7 6 2 U 6 7 6 5 26 116 131 67 .16 149 195 124 Z8 4 14 . 129 205 156 0000 1 7 6 6 6 25 11 10 10 10 77 18 12 12 12 137 9 Q 10 o 11 12 3 2 1 15 79 180 162 42 14 14 14 188 16 31 127 148 . 69 16 16 16 229 17 18 58 113 90 23 . 17 17 252 17- 17 19 64 98 64 , 19 17 259 5 a.m. 7 p.m. 20 54 54 20 33 33 6 et 6 7 6 S 25 128 149 81 12 139 . 197 136 8 .7 7 7 12 10 10 10 34 80 Z8 4 13 107 202 171 32 12 . 12 12 129 o 9 3 14 54 176 183 72 14 14 14 173 Q 10 e 11 2 1 15 18 124 174 no 16 15 15 206 16 16 57 143 136 42 16 16 227 12 16 16 18 98 ' 144 96 . 18 16 234 N NW W sw. s SE . E NE Hobiz. other design temperatures are given in Table 26 in a later section, Effect of Deviation from Design Conditions. Tables 16 and 17 may be used for other types of glass with good accuracy, by using the factors given in Table 18. Table 16 values are multiplied by the appropriate factor given in Table . 18 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 vection and radiation, two steps are required. First, Table117 values are multiplied by the appropriate coefficient of X. listed in Table 18. Second, Table 19 values are multiplied by the appropriate coefficient of Y listed in Table 18, and added to the first value. All convection and. radiatipn gain values for double glass were computed for a J-in. air space. No great error is involveil in cooling load estimates if: these are used for double:glass with other air spaces. .' - '' Example 14: Find the total instantaneous heat gain through a single sheet of regular plate glass in a southwest wall at 2 p.m. sun time and 40 deg north latitude on. August 1. The maximum dry-bulb temperature for desigo is 98 F.; the atmos-. phere is clear. The indoor temperature is 75 F. ' . Solution: From Table 16 the heat gain due to transmitted radiation is 148 Btu per (hr) (sq ft) for common window glass; from Table 18, the factor for regular plate1 glass is 0.87. The coefficient of X in Table 18 is 1.0, while A is found from Table 17 for common window glass for the same hour, orientation and latitude. The co efficient of Fin Table'18 is0.25, while the F value is found from Table 19for asouth- Cooling Load 291 Table 17. Instantaneous Rates of Heat'Gain by Convection and Radiation prom i Single Sheet of Unshaded Common Window Glass For Clear Atmospheres and 18 Deg Declination, North (August-1) . For 76 F Indoor Temperature ' Note: For total instantaneous heat gain, add these values to the Table ,16 values. Sun . Time Dbt- Nobth Bulb Latitude Deo F Degrees 5 a.m. 6 7 8 9 10 11 12 1 p.m. 2 3 4 5' 6 7 8 9 74 74 75 77 80 83 87 90 30,40,50 93 94 95 94 93 91 87 85 83 Instantaneous Heat Gain in Btu peb (hr) (sq ft) N NE . E -1 0 0 2. 5 8 13 17 20 21 22 21 20 18 13 11 8 -1 --1 11 33 56 79 9 11 *13 . 15 17 17 20 20 21 21 22 22 21 21 20 20 18 18 13 13 11 11 88 SE -1 0 2 5 8 11 16 18 21 21 22 21 20 18 13 11 8 S SW -1 -1 --1 -1 00 32 65 10 15 19 22 23 8 14 18 22 24 24 26 22 25 20 23 18 19 13 13 11 11 88 W NW Hob. -1 -1 -1 -1 -1 . 0 002 225 55 8 8 8 13 13 13 18 17 17 21 22 20 25 24 22 26 26 24 26 25 24 24 24 23 22 20 20 18 13 13 13 11 11 11 88 8 west wall at 2:00 p.m. and 40 deg north latitude. The correction for design dry-bulb temperature is found from Table 26 to be 1.0 Btu per (hr) (sq ft) per degree difference from 95 F design temperature. The total instantaneous heat gain is, from Equa tion 7a, , . q = 0.87 X 148 + 1.0 X 24 + 0.25 X 27 + 1.0 (98 - 95)' = 162.7 Btu per (hr) (sq ft). Design Tables for Rolled Figured Glass ' Tables 20 and 21 give design values of instantaneous rates of heat gain for a number of common patterns, of single vertical sheets of rolled figured glass. The tables are for a solar declination of 18 deg, which corresponds to a nominal August 1 day, and are based upon the solar intensity values for a clear, atmosphere as given in Table 5. The values are given1 in terms of corrections to apply to Tables 16 and 17. The heat gain due to-transmitted solar, radiation is found by multiplying the Table 16 values by the approximate percentages given in Table 21. To obtain instan taneous rates of heat gain by convection and radiation, Table 19 values are multiplied by1 the appropriate value of Y from Table 20 and then added to Table 18. Application Factors to Apply to Tables 16,17 and 19 to Obtain . . Instantaneous Rates of Heat Gain for Various Types of Single t - Flat Glass and Combinations of.Two Sheets of Flat Glass ' ' , ` Spaced at 1 in. . ' `. Glass `' Nobmal Incidence Tbansmtitakcb Factor to Afplt to Table 16 Single Common Window. Single Regular Plate Single Heat Absorbing Plate Double Common Window . ' Double Regular Plate . Heat Absorblag Plate Outdooral Regular Plate Indoors ' - / , 0.87. 0.77 0.41 0.76 0.60 0.35 1.00 . -0.87 0.46* . 0.85 0.66* 0.37* b Cr precision, increase factors 10 percent when glass is in the shade. ' - X values are Table 17 valued. 1 Y values are Table 19 values. Factob to Aptly to Table 17 . . - 1.0(X)b.+o.ooo 1.0(X) + 0.25(F) 1.0(1) + 1.00(F) 0.6(X) + 0.10(F) 0.6(X) -f-0.55(F) 0.8<X) + 0.75(F) 292 CHAPTER 12 1952 Guide " Table 19.. Values op Y to be Used with Factors in Table 18 and Table 20 in the Determination op Instantaneous Rates op Heat Gain Due to Convection and Radiation pob Vabious Types op Single Glass and Combinations of Two Sheets' " op Glass Spaced at i 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 40 Degrees North Latitude Values of Y in Btu per (hr)- (sq ft)* N NE E SE 0 4 2 2. 2 3 3 3 3. 3 3 3 2 4 0 01 16 18 24 30 22 33 16 30 5. 25 3 12 33 3.3 33 3 3 3 3. 22 X1 00 0 9 20 25 29. 27 21 15 3 3 3 3 2 1 0 S ' SW 0 1 2 _ 2 8 14 18 19 19 16 10 4 2 1 0 0 1 2 2 3 3 3 12 22 27 30 29 23 14 2 W NW Horiz. 0 -0 11 22 2. 2 33 33 33 3 .3 10 - 3 24 4 31 . 15 36 23 34 ` 27 24 21` 33 0 3 11 21 32 37 42 45 44 41 35 26 17' 6. ' 1 Sun Time . Latitude ' SE s SW Sun Time Latitude 5 a.m. 6: 7 8 - 9 10 11 12 1 p.m. 2 3 4 5 6 7 30b Degrees North Latitude 0 0 0. 5 a.m. 7. 1 . 1 6 18 2 2 7 22 2 2 8 24 3 3 9 22 16 6 3 3 5 7 9 9 6 3 3 4 14 21 10 11 12 . 1 p.m. .2 50b Degrees North Latitude 3 5 27 3 3 3 26 4 2 2 21 5 1 1 11 5 0 0 07 * Values of 7 for 8 and 9 pm. are zero. ' -. b For N, NE, E, W, NW and horizontal use 40 deg North Latitude values. SE s SW 2. . 0 - .0 13 - 1 1 22 2 2 28 3 2 30 13 . . 3 31 20 3 27 25 5. 20 27 17 9 25 26 3 22 32 3 16 27 2 ' 2- 11 00 33 31 26 17 7 the corresponding Table 17 values. The total instantaneous heat gain is the sum of the gain due to transmitted solar , radiation and the gain by convection and radiation. `. . . The values given in Tables 20 and 21 are based upon an A.S.H.V.E. research paper20 to which the reader is directed for additional data. The values in Tables 20 and 21 may be used with fair precision for other pat terns of similar transmittance and surface characteristics. For example, the data for hammered glass may be used for glass having shallow, closely ' spaced ribs or for glass having small, closely-spaced circular indentations. Because some patterns have distinct. orientation properties, no attempt has been made to give values for non-vertical glass. Design Tables for Glass Block Walls : Tables 23 and 24 give design values of instantaneous rates of heat gain for sunlit walls of Type I pattern 8-in. hollow glass block for a solar de clination of 18 deg (see Table 22 for description of block patterns). These tables are based upon the solar intensity values for a clear atmosphere as given in Table 5. 'For solar energy transmittance data the reader is referred to reference 18. Table 23 presents values of transmitted direct Cooling Load / -293 Table 20. Application Factors to Apply to Tables 17. and-. 19.to Obtain In stantaneous Rates of Heat Gain fob Vertical Single Sheets - op Rolled Figured Glass -Having Normal Incidence Transmittances and Listed Thicknesses (Smooth Side Indoors, Figured Side Outdoors) J(See Table SI for Factors to Apply to Table 16 Values)___________________________ . Glass Pattern . Normal Incidence .Transmittance Thickness, Inches Factor to Applt to Table 17 Hammered Hammered, etched both sides ' Deep ribs on } in. centers Hammered heat absorbing . Hammered heat absorbing, etched both sides 0.75 0.67 0.77 approx. 0.21 0.14 Hj 1.0(X) + 0.50(F)b'c Hi 1.0(X) +0.65(Y)d Hi i.0(X) + 0.60(F)* a l.O(X) +1.15(F)' H LOGO + 1.40(F) * X values are.Table 17 values ' b Y values are Table 19 values . c Use 0.40(F) for east and west glass . Use 0.60( F) for east and west gift** * Use 0.35(F) for east and west glass Use 0.95( F) for south gift.*** . Table 21. Instantaneous Rates, of Heat Gain Due to Transmitted Direct and Diffuse Solar Radiation by Unshaded Rolled Figured Glass- Multiply the Table 16 Values by These Percentage Factors ' For Clear Atmospheres and 18 Degrees Declination, North (August 1) For . .. 80, ^0, and 60 Degrees North Latitude - Note: To obtain total instantaneous heat gain add adjusted Table 16 values -.- to adjusted Table 17 values . / Instantaneous Heat Gain Due to Transmitted Solar Radiation as a Percentage op Single Sheet op Common Window Glass . Sun Tims - Hammered Hammered and Etched AM . ; i ** N, NW W, SW NE* E SE s N, NW . W,SW NE E SE S 5 a.m. 6 7 8 9 10 11 7 p.m. 6 5 4 3 2 1 . 80 80 85 70 80 ' 60 80 85 85 75 80 60 80 . 80 85 80 80 60 80 75 85 80 75 60 . 80 . 60 80 80 60 -60 80 65 75 75 65 60 80 80 60 70 65* 60 80 80. 80 60 65* 60 '65 75 55 60 65 75 50 60 60 70 : 55 60 55 65 55 60 50 55 55 50 55 50 55 50 60 50 50 50 60 60 50 50 Sun Time 5 a.m. 6 7 8 9 11 7 p.m. 6 5 4 .3 1 Ribs.on i In. Centers Hammered Heat Absorbing 60 . 75 85 25 60 25 20 25 20 25 60 80 85 30 60 25 20 25 20 25 60 65 85 40 60 25 20 25 20 25 60 40 80 50 55 . 25 . 20 20 20 . 25 60 30 70 55 35 25 20 20 20 20 60 40 40 55 35 25 20 20 20 - 20 60 60 - 35 40 35b 25 25 20 20 20 60 60 60 35 45b . . 25, . 25 25 20 20 t . PM-> N. NE . E, SE NW W SW S ' N. NE E, SE NW `w ` SW S Sun Time AM. l^ 5 a.m. 7 L 2 10 11 12 7 p.m. S 3 * 2 1 t PM-> Hammered and Etched Heat Absorbing N, NW W, SW NE E SE .8 20 15 15 10 20 * Decrease values 10 percent for 20 . 15 15 10 20 30 deg latitude: increase 15 percent for 20 10 15 10 20 50 deg latitude 20 10 15 10 20 20 10 10 10 10 b Increase values 30 percent for 20 15 10 10 10 50 deg latitude 20 20 10 10 10 20 20 20 10 10 N, NE E. SE NW W SW S i!l. . 294 vCHAPTER 12 -, 195 2. 'Guide Table 22. Description or Glass Block Patterns A- Ouidoor surface Elevation Section of Htdlow Glass Block to Indicate Location of Surface Patterns Type I A, D: B: C: E: --Smooth Face . Smooth . , Wide vertical ribs or flutes Wide horizontal ribs or flutes None - . ' Type IV--Light Diffusing A, D: Close pitch deep horizontal corrugations B, C: Vertical light diffusing prisms E: None Type II A, D B, C --Semi-Light Diffusing Narrow vertical ribs or flutes Etched or stippled . Type IVA--Light .Diffusing ; Same as IV except tions vertical corruga E None `- . . >. Type V -Light Directing A, D: Close pitch deep vertical cor Type III--Light Diffusing rugations ; A, D Narrow vertical ribs or flutes B, C: Horizontal light directing B, C Etched or stippled prisms . E Glass fiber screen None Table 23. Instantaneous Rate op Heat Gain Due to Transmitted Direct and Diffuse Solar Radiation by. Unshaded Walls of 8-in. Hollow Glass Block of Type I Pattern . For Clear Atmospheres and 18 Deg Declination, North (August 1) Note: For total instantaneous Heat gain add these values to Table 24 values Sun Tim ' H ? AM-* J 4- a o :Z. . eo B z m Q . z oH Q g 6 a.m. 7 8 9 10 11 12 5 a.m. 6 7 8' .9 10 11 12 5 a.m. e 7 8 9 10 11 . 13 6 p.m. 5 4 3 .. 2 1 7 p.m. 6 5' 4 3 2 1 7 p.m. 6 5 4 3 2 1 Instantaneous Heat Gain in Btu peb (hb) (sq ft) N NE E SE s SW W NW 4 5 5 5 6' 8 6 1 5 4 5 5 6 6 6 4 .5 4 4 5 5 8 6 45 59 42 25 12 8 6 3 50 54 34 18 ,8 6 .6 28 ' 53 44 26 12 6 6 6 55 94 94 59 2712 7 3 67 98 90 59 29 13 6 27 77 101 88 57 29 14 6 12 2 29 4 38 5 34 6 24 9 13 10 89 00 17 2 36 4 47 5 47 10 35 15 22 18 13 17 41 22 3 44 4 57 7 60 16 54 25 34 32 20 34 22 33 44 55 66 7 6 87 00 22 44 44 5 5. 56 76 13 6 11 22 44 44 55 65 10 6 20 6 2 3 4 5 6 6 6 0 2 4 4 5 6 6 6 1 2 4 4 5 5 6 6 T PM-* N NW W sw- S SE E NE. Cooling Load ' ' ' 295 Table1 24. 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 1) For 75 F Indoor Temperature Note: For total instantaneous heat gain add these values to valuies in Table 21, or Table 23 adjusted by Table 25 factors. Sum Time Dry- Bulb Farr. ' 5 a.m. 6 7 8' 9. 10 11 12 1 p.m. 2 3 4 5 6 7 8 .9 74 74 75 77 80 83 87 90 93 94 95 94 93 91 87 85 83 ' . Instantaneous Heat Gain in Btu per (hb) {bq ft) . N NE E SE - s : . SW W NW. 40 Degrees North Latitude -1 2 3 2 2 j4 6 8 10 11 ' 13 13 13 15 13 9 8 -1 5 17 23 -22 14 8 10 12 12 13 13 12 11 9 6 t5' -1 6* 19* 28* 35 38 31 18 16 17 , 18 17 15 13 10 6 4 -1 5 15 23 29-. 34 34 28 16 13 13 13 12 11 9 6 5 -l 0 1 3 .. 7 -1 -1 0 -0 11 22 34 14 . 5 21 -7 25 11 28 27 27 39 5 8 10 14 30 23 . 46 18 47 15 45 13 37 . 10 21 43 46 44* 37* 23* 6 99 4 5 : 6 --1 0 1 .2 3 5 '`7 9 11 13 19 32 37 31 17 6 5 Sum Time DryBulb Latitude SE S SW Latitude SE S SW 5 a.m. 6 9 10 12 1 pan. 5 8. .74 . 74 75 77 80 83 87 90 93 94 95 94 93 91* 87 ' 85 83 30b Degrees North Latitude -1 -1 -1 u 300 13 1 1 22 2 .2 28 3 4 31 6 6 28 10 7 20 14 9 50b 12 17 . 18 Degrees 13 18 32 North Latitude 14 16 41 14 15 45 13 13 43 12 11 34 8 8 17 6 6 8 555 -1 ; 7 15 23 29 34 37 . 35 25 14 13 13 12 11 9 6 5 -1 0 1 2 8 17 24 30 33 34 30 22 14 12 9 6 5 --1 0 1 2 3 4 6 19 33 41 45 46 45 38 25 .12 5 _ y,,r tyPs III, IV, IVA aod V patterns and 30, 40 and 60 deg latitudes, multiply east wall values for 6 I and s a.m. by 1.40, and west wall values for 5, 6 and 7 p.m. by 1.25. For N, NE, E, W and Nff use 40 deg North Latitude values. and diffuse solar radiation, while Table 24 gives values of instantaneous rates of heat gain by convection and radiation from the wall. The latter values are for an indoor temperature of 75 F and a 95 F muTimiim 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. Because 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 26 gives cor rections to be applied for other design temperatures^ To obtain transmitted direct and diffuse solar radiation for other types oi 8-in. block, the Table 23 values are multiplied by the approximate per- 296 CHAPTER 12 1952 Guide . Table 25. Instantaneous Rates of Heat Gain Dub to Transmitted Directand. Diffuse Solab: Radiation by Unshaded Walls of 8-in Hollow Glass Block of Types II, III, IV, IVA and V Patterns Multiply the Table SS Values for Type I by These Percentage Factors For Clear Atmospheres and 18 Deg Declination, North (August 1) . . . For SO, 10, and SO Deg North Latitude 'Note: To obtain total instantaneous heat gain add adjusted Table SS values to the Table 24 values. . Instantaneous Hbat Gaik Dub to Transmitted Solar Radiation as a Pebcbntaob op Ttpb i Pattern Sun Time . Type n Pattern . Ttpb III Pattern AM i; N, NW, W, 8W NE E SE s N, NW, W, SW NE E SE S 5 a.m. 6 7 8 9 10 11 12 7pan. 6 5` 4 3 .2 1. r PM -- ' 100 100 100 . 100 100 100 , 100 . 100 N. NE, E, SE 100 .100 95 95 90 90 95 90 95 85 95 95 100 95 100 100 NW l W 100 90 90 90 ' 90 95 95 100 SW 100 100 100 100 90 95 100 100 S 70 70 70 70 70 70 70 70 N, NE, E,SE 70 70 70 70 65 65 70 70: 65 60 65 70 65 60 65 70 65 65 70 65 70 70 75 65 70 70 80 75 70 70 75 90 NW W SW S ... Sun TXmb . . Ttpb IV Pattern Ttpb IVA Pattern AM -- i ... N, NW, W, SW NE E SE s. N, NW, W, SW NE E SE S 5 Bjn. 6 .7 ;. 8 0 10 11 12 7pja. 6 5 4 8 2 1 85 45 35 75 55 55 45. 35 80 55 55 45 35 60 . 55 55 45. 30 40 55 55 , 50 25 30 60 55 55 35 30 50 55 55 45 35 40 55 55 55 50 45 pi- N, NE, IS, SE NW W : SW -S Sun Time . . . Ttpb V Pattern AM -- .1 - N. NW, W. SW NE E SE s 5 ajn, 8 7 8 9 10 . . 11 12 7 pjn. 6 6 4 3 2 1 - 80 ' 35 35 30 GO 60 35 35 30 60 60 35 40 35 60 60 50 65 50 60 60 80 90 90 60 GO 70 105 105 90* 60 60 80 110 105* 60 60 60 85 115* 55 55 55 55 55 55 55 55 N, NE, E,SE 45 35 35 35 35 40 45 45 50 65 55 85 55 70 55 55 NW W 30 55 30 55 35 55 45 55 65 50 90 60 105 95 100 115 SW S Designation of Block Type II--Semi-Light DiffusingIII--Light Diffusing IV--Light Diffusing IVA--Light Diffusing V--Light Directing . . ; PL- . . N, NE, E, SE NW W SW S * Beduce by 30% (or 30 deg N lat itude only. - Table-26. Approximate Corrections to Tables 17 and 24 for Deviations .. ' from Indoor and Outdoor Design Temperatures . For each degree the design room temperature exceeds 75 F, subtract correction. For each degree the design outdoor dry-bulb temperature exceeds 96 F, add correction. Apply these corrections to each value in Table 17 or Table 24. Glass Type Single Flat or Rolled Figured Glass Double-Flat Glass and Glass Block Correction Btu per (hr) (sq pt) 1.0 0.5 . Cooling Load 297 centages given in Table 25. 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 walls of some patterns. ,, . Example IS: Find the total instantaneous heat gain through an.east wall of 8-in. hollow glass block of Type V pattern at 8 a.m. and 50 deg north latitude. The design temperatures are 75 F indoors and 95 F maximum outdoor dry-bulb, clear atmosphere. . Solution: The gain due to transmitted solar radiation is found from Table 23 for Type I pattern. The factor for Type V is found from Table 25. The convection and radiation gain is found from Table 24 (note the footnote). The total instantaneous heat gain is, from Equation 7a, g = 86 X 0.65 + 28 X 1.4 = 95.2 Btu per (hr)(sq ft). Effect of Deviations from Design Conditions If the indoor temperature differs from 75 F, or the design outdoor dry- bulb temperature differs from 95 F, corrections can be made to the convec tion and radiation gain values for flat glass, rolled figured glass, and glass block according to the schedule in Table 26. ' The effect of the humid industrial type atmosphere is to cause a con siderable reduction in heat gain, if all factors except solar intensity remain the same. Reference 19 gives heat gain values for four orientations at 40 deg north latitude on August 1 for several types of flat glass and glass block, and solar intensities typical of humid industrial atmospheres. These data show that the following approximate reductions, based on total gain for the day, can be expected: 20 percent for all types of glass and glass block in east or west facing walls; 10 percent for south facing flat glass,; 5 percent for south facing glass block walls.. " Shading of Glass Areas--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: where n tan 0 cos y r,r, tan 0 tan y Tt tan y -f cos -y ' (10) . rj = s/1, 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 7. Special cases not covered by the tabulated data may be solved analy tically;21 however, the design conditions chosen will yield a satisfactory approximation if used without correction for any time during the summer period. Example 16: Estimate 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). . . . Solution: From Table 16, the instaneous' rate of heat gain, due to transmitted direct and diffuse solar radiation, is 180 Btu per hr. From Table 7,0 is 45.5 deg and 298 CHAPTER 12 1952 Guide y is 16 deg. From Equation 10, the fraction of the total window area that is receiving . direct solar radiation is: . ,, . 0.1 tan 45.5 0.0167 tan 45.5 tan 16 i = 1 ~ co- s ,1g6 - 0.167 tan 16 + -- -- cos lo .--------- = 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 applied only to the Table 16 value. Note also a small error results from the fact Table 27. Effect of Shading upon Instantaneous Solab Heat Gain Through Single Thickness of Common Window Glass Type op Shading Finish on Side Exposed to Sun Fraction op Gain Through Un shaded Window Canvas Awning 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 set at 45 degb ' Inside Venetian Blind, Slats set at 45 degb Inside Venetian Blind, Slats set at 45 degb Inside Venetian Blind, Slats set at 45 degb Outside Venetian Blinds Slats set at 45 degb , Outside Venetian Blind, Slats set at 45 deg, extended as an awning0 Outside Shading Screen,1} solar altitude 0-20 deg Outside Shading Screen, solar altitude 20-40 deg Outside Shading Screen,*1 solar altitude, above 40 deg Dark White Medium color Dark color White - Medium color : Dark color White Medium ' Aluminum Dark color Cream . Any color Dark color Dark color Dark color 0.25-0.35 0.45 0.63'' 0.80 0.72 0.81 0.90 0.62 0.74 0.70 . 0.86 0.30 - 0.40 0.75-0.43 0.43-0.22 0.22 . * Roller shades are assumed to be opaque. Some white shades may transmit -considerable solar radia 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. . . ' c Commercial shade with wide slats. . Metal slats 0.05 in. wide, spaced 0.063 in. apart, and set at 17 deg angle with horizontal. At solar alti tudes below 38 deg some direct solar rays are allowed to pass between slats, and this amount becomes progres sively greater at low solar altitudes. that the diffuse radiation is not shaded to the same extent as the direct radiation. The total instantaneous heat gain therefore .is: . g = 3 X 5 (0.851 X 180 + 26) = 2690 Btu per (hr)(sq ft) A window such as the one used in Example 16 would customarily be pro vided with an additional shading means for use particularly when directly sunlit. Conventional shading devices include awnings, shades, and screens of various types. . Experimental work conducted at the A.S.H.V.E. Research Labora tory and other research23 to determine the effectiveness of various types of window shades, have been used as the basis for the recommended ratios in column 3 of Table 27. 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, therefore, must be considered as approximate, only, and will have to be used with considerable judgment. An inside shade is effective to the ex Cooling Load 299 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 The difference between instantaneous heat gain and instantaneous cool ing load has been mentioned previously; its practical importance is suffi cient to warrant further consideration. Fig. 5 offers a simplified schematic illustration showing how the radia tive part of the instantaneous heat gain is first absorbed by solid objects, and is not encountered by the conditioning equipment as a cooling load until some later time, when it finally appears in the air stream entering the equipment. While it is true that some lag also is inherent in convective heat transfer and the time required to change the air in the conditioned space, this is usually of the order of a few 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 as the 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 investiga tors13' 2425 have made a study of the problem and have presented many useful data. Tables 12,13,16,17,21,23, and 24 are all based on instantane ous rates of heat transfer. Hence, practical judgment and experience offer the only basis of procedure. Until the needed data become available, it is recommended that the 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 which a different temperature prevails, the transfer of heat through the separating structural section must be considered. Calculations are made according to the relation: . q = UiA ,(lb -- l,) Btu per hour. (11) where XJi = coefficient of overall heat transfer between the adjacent and the condi . tioned space, Btu per (hour) (square foot) (Fahrenheit degree). A-, = area of separating section concerned, square feet. = air temperature in adjacent space, Fahrenheit degrees, fi = air temperature in conditioned space, Fahrenheit degrees. Magnitudes of l/j may be obtained from Chapter 9. . The temperature 300 CHAPTER 12 1952 Guide A may have1 any value over a considerable range, according tb conditions in the adjacent spacer The temperature in a kitchen or boiler robin may be as much-as 15 to 50 deg above the outdoor air temperature. It is recom mended that actual temperatures be measured in adjoining spaces wherever practicable. Where nothing is known, except that the adjacent space is of conventional construction and contains no heat sources, it is recommended that the difference (fb -- t,) be taken as the difference between the out door air and conditionecTspace design dry-bulb temperatures minus 5 deg. In some cases it may be that the air temperature in the adjacent space will correspond closely to the outdoor air temperature at sill 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 from1 Table 13. 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. Ventilation required is pri- Fig. 5. Origin op 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. . marily dependent upon the number of occupants and upon the materials and apparatus within the space which may give off odors. For spaces having ceiling heights 10 ft or less, the total requirement should be checked against the volume, and in no case should the ventilation air rate be less than one air change per hour. In spaces having ceilings higher than 10 ft where the occupant load is low, a check calculation can be made against the volume of the space below an assumed 10-ft ceiling. Infiltration must never be counted upon to provide ventilation, because on still days there will be little or no infiltration. Infiltration. The principles of infiltration calcinations have been dis cussed in Chapters 10 and 11, 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 10, 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 the total crack length on all sides of the building, for the wind would not act simul taneously on all sides at once. In no case, however, should less than half Cooling Load 301 of the total crack length be figured. A knowledge of the prevailing wind direction will aid judgment in this consideration. : Cooling-load infiltration for doors*6 may be obtained from Table 3, Chapter 10. For conditions other than those covered, the notes appended to Table 3 will provide a basis for estimates.^ The tabulated data may also be used as the basis of estimates for interior doors between an air-condi tioned and a non-air-conditioned space. ,.j. . : . Infiltration load, must be included whenever the new air introduced through the system, is not sufficient to maintain excess pressure within the enclosure to prevent the infiltration. Whenever economically feasible, it is desirable to introduce sufficient outdoor air through the air-conditioning equipment to maintain a constant outward escape of air, and thus eliminate the infiltration portion of the load. The pressure maintained must, of course, be sufficient to overcome wind pressure through cracks and door openings. When this condition prevails it is not necessaiy to include any infiltration load. When the quantity of new air introduced through the cooling equipment is not sufficient to. build up the required pressure to offset infiltration, the entire infiltration load should be included in the cooling load calculations. . . Total Outside Air Load. To determine the design cooling load caused by.the introduction of outside 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 rate. 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 calculations. Refer to Chapter 3, and also section on Apparatus-Dew Point in Chapter 29. The following equations are considered to be of sufficient precision for use at usual design condi tions, as their accuracy is within 1 percent. ,, / 0.00923\ , SensibleLoad q, =, Q X 60 X 0.244 X0.075 f 1---------1 (f,, - ,) . Latent Load Total Load =.Q X 1.08 (t0 -- fi), Btu per hour q. = Q X 60 X 0.075 X 1076 (W,, - W,) = Q X 4840 (W0 -- Wi), Btu per hour qt = ?. + q (12) (13) (14) where - Q = rate of entry of outside air, cubic feet per minute, to = outdoor dry-bulb temperature, Fahrenheit degrees, fi = indoor dry-bulb temperature, Fahrenheit degrees. W0 = outdoor humidity ratio, pounds moisture per pound of dry air., Wi = indoor humidity ratio, pounds moisture per pound of dry air. 0.075 = standard air density, pounds per cubic foot. 0.244 = a constant approximating the specific heat of dry air corrected for mois ture Btu per (pound) (Fahrenheit degree). 1076 = a factor approximating the average Btu released in condensing one pound of water vapor from air. Standard air weight (0.0075) lb per cu ft) is recommended for use in all 302 CHAPTER 12 1952 Guide 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 dehkmidified 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 out door 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 sensible and latent heat loads within the space must be included. In filtration must be included in the space load since this air enters the doors and windows, and its heat and moisture load must be offset by the intro duction of cooler, dryer air to the space. However, since ventilation air is taken through the conditioning equipment and cooled, this portion does not become a part of the space load. To determine the total load on the refrigeration machine, the ventilation air load must be included in the grand total load. ' Example 17: For outdoor design conditions of 95 F dry-bulb and 75 F wet-bulb, and indoor design conditions of 80 F dry-bulb and 67 F wet-bulb, and for the supply of outdoor air at the rate of 1000 cfm and the exhaust of room air at the corresponding rate, calculate the total, sensible and latent heat gains. Solution: Substituting in Equation 12: g. = 1000 X 1.08 (95 - 80). = 16,200 Btu per hr. From psychrometric data Wo = 0.01413, Wi = 0.01122. Substituting in Equations 13 and 14: g. = 1000 X 4840 (0.01413 - 0.01122) = 14,100 Btu per hr. , gt = g. -f- g. -- 30,300 Btu. - Many cooling coil manufacturers publish tables giving psychrometric data based on the average conditions of the leaving air for various coil temperatures, air velocities, and entering dry-bulb and wet-bulb condi tions. When these tables are used, it is necessary to calculate the mixed air condition entering the coil, and determine from the tables what coil and air velocity will produce the desired leaving air conditions as required for the space to be conditioned. When cooling coils are listed as 80 to 95 per cent 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. HEAT SOURCES WITHIN THE CONDITIONED SPACE People. The rates at which heat and moisture are given off by human, beings under different states of activity are given in Table 28. In many applications these sensible and latent heat gains become a large fraction of the total load. Appreciable variations in heat-emission rates must be recognized according to the age and sex of the individual, state of activity, environmental influences, and duration of occupancy (since for short occupancy the extra heat and moisture brought in by people may be a significant factor). While Chapter 6 should be referred to for detailed information, Table Cooling Load 303 28 in this chapter summarizes practical data representing conditions commonly encountered. Lighting. In general, the instantaneous rate of heat gain from electric lighting26 may be calculated from the following relation total light ^ j use (special allow- wattage (factor * (ance factor X 3.41, Btu per hr. (15) The total light wattage is obtained from the ratings of all fixtures installed, both for general illumination and for display use. Table 28. Rates of Heat Gain fbom Occupants of Conditioned Spaces" Degree op Activity Typical Application Total Heat Adults, Male Btu/Hb Total . Heat Adjusted Btu/Hb . Sensible Heat Btu/Hb . Latent Heat Btu/Hb Seated at Rest...'.......................... Seated, Very Light Work........... Moderately Active Office Work Standing, Light Work; or Walking Slowly............... .Y.____ Walking; Seated........................... Standing; Walking Slowly......... Sedentary Work............................ Light Bench Work........................ ModerateJOancing........................ Walking 3 mph; Moderately Heavy Work........... Bowling.....................'___ -___ ... Heavy Work....... .................. ;____ Theater-Matinee.... Theater-Evening___ Offices, Hotels, Apartments............... Offices, Hotels, Apartments............... Department Store, Retail Store Dime Store............... Drug Store . Bank.......................... Restaurant6............... Factory...................... Dance Hall Factory.................. :. Bowling Alley........... ' Factory...................... 390 390 450 475 550 550 490 . 800 900 1000 1500 330 350 . 400 450 180 195 195 200 450 500 550 750 850 .. 1000 1450 200 . . 200 220 220 245 " 300 ' 465 150 155 205 250 * 250 . 300 330 530 605 ' 700 985 4 Note: Tabulated values are based on 80 F from dry-bulb temperature. For 78 F room dry-bulb, the total heat remains the same, but the sensible heat values should be increased by approximately 10 percent, and the latent heat values decreased accordingly. ,. bAdjusted total heat gain is based on normal percentage of men, women, and children for the application luted, with the postulate that the gain from an adult female Is 85 percent of that for an adult male, and that the gain from a child is 75 percent of that for an adult male. 'Adjusted total heat value for sedentary work, restaurant, includes 60 Btu per hour for food per individual (30 Btu sensible and 30 Btu latent). . ' . d For bowling figure one person per alley actually bowling, and all others as sitting (400 Btu per hour) or standing (550 Btu per hour). * ' The use factor is the ratio of the 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 to 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 ballast. For ventilated fixtures, recessed fixtures, and the like, manufacturers' or other data*7 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 RatingX / Load \ - { Motor. Efficiency ) X (pactorj X 2644- BtU ' hr` . (16) It is assumed that both the motor and the driven equipment are within 304 CHAPTER 12 Table 29. Rate op Heat Gain From Appliances WITHOUT HOODS*' b Appliance Capacity Over-all Dimen sions (Less Lbcs Control and Handles: A--Automatic Last Dimension M--Manual is Height) Inches Miscellaneous Data Manu facturer's Rating Watts Coffee Brewer and Warmer Heal Coffee Brewer Unit with Heal . Tank .. ; Coffee Urn 3 gal 5 gal . Doughnut Machine Egg Boiler . 2 cups Food Warmer, with Plate Warmer,"per sq ft of top surface Food Warmer, alone, per eq ft of top surface Fry Kettle . 11H lb fat Fry Kettle 25 lb fat Griddle, Frying Griddle, Frying Grill, Meat Grill, Sandwich Roll Warmer Toaster, continuous 300 sllces/hr Toaster, continuous . 720 sllces/hr Toaster, pop-up . 210 sllces/hr Waffle Iron 20 waffles/hr 20 x 301 20 12x23 x21 18 (Diam.) x 37, 22x 22 x 57 10 x 13x 25 12 (Diam.) x 14 16 x 18x 12 18 x 18x8 24 x 20 x 10 14 x 14 x 10. 13 x 14 x 10 23 x 23 x 29 15 x 15 x 28 20 x 15 x 28 12 x 11 x 9 12x13x10 Restaurant Electrical Appliances M M Brewer 660 w Warmer 90 w 600 90 2000 w Water heater, 2960 w brewer 4960 A Nickel plated , A Nickel plated 4500 5000 . A Exhaust System 4700 ' M 1100 Insulated, separate heat A . unit for each pot; plate 400 ' warmer in base A. A A A A A A A .. A A A A -. Area 12 x 14 in. - Area 18 x 14 in. Area 23 x 18 in. Area 10 x 12 in. Area 12 x 12 in. Three drawers 2 slices wide 4.slices wide ' '4 slice 7 in, diam, waffle 300 2600 7000 2350 4000 3000 1650 1000 2200 3000 2450 760 Btu/Hr Main taining Btu per Hour Recommended Rate of Heat Gain Btu per Hour Sensible Latent Total 2000 300 17000; . 306 15000 17000 16000 3750 . 2600 3600 1350 . 500 900 230 4800 2200 3400 6000 1200 ' 350 220 60 ' 1200 1120 290 6000 1600 2300 0, SOO 3700 5700 ` 5000 . 2000 . 350 , 700;. 1000 ' S900 24000 8000. 13500 10250 * 5600 3400 7500 10250 8400* 2500 400 1100 2000 2800 5000 1000 1000 000 6000 6000 2000 600 \ 200 1600 3800 3100 5300 3000 2700 2400 6100 . 6100 . 4?00 1100 350 . ; 55Q_ 2400 ` 4000 ' 5700 9500 1700 4800 2900 , 8200 2100 . 6000 700 3400 309 2700 1300- 0400 * 2600 .8700' 900 5800 750. 1850. fSgamrfBMit iifiiiiiiiiiiiliiilffllifHff . 1952 Guide I Cboling Load Restaurant Gas-Burning Appliances ' Coffee Brewer and Warmer H gal Coffee Brewer Unit with 4> gal Tank 10 x 30x26 Tank Coffee Urn Food Warmer, per sq ft of top surface 3 gal _ 5. gal ' 12 x 23 x 21 18 (Diam.) x 37 " Fry Kettle IS lb fat 12x20x18 Fry Kettle 28 lb fat......... 15 x 35 x 11 Grill 22 x 14 x 17 -. M M A .A - M A A M. Stoves. Short Order Open Top, per sq ft top Closed Top. per sq ft top Fry Top, per sq ft top Toaster, Contlnous 360 sllces/hr Toaster, Contlnous 640 sllces/hr 15 x 15 x 28 20 x 15 x 28 M M M A A , Brewer Warmer 4 Breviers and Tank Nickel plated Nickel plated . Water bath Area 10 x 10 Area 11 x 16 Insulated, Grill surface of 1.4 sq ft Top burner 22,000 Btu/ hr Bottom burner 15,000 Btu/hr . Ring type burners Ring type burners Tubular type burners 2 slices wide " 4 slices wide . 3400 500 500 2000 14250 24000 37000 3400 4700 600 3000. 4300 1350 400 7200 850 100 1800 1*700 600- 6000 2500 2500 3900 . 8900 5000 7800 830 4200 7200 14400 430 2800 4800 3600 1230 7000 12000 18000 14000 11000 12000 12000 20000 . 10000 14000 4200 3300 3600 7700 12000 4200 3300 3600 3300 '5000 8400 6600 7200 11000 17000 Coffee Urn 3 gal 5 gal Coffee Urn 3 gal 5 gal Food Warmer, per sq ft of top surface Food Warmer, per sq ft of top surface Restaurant Steam-Healed Appliances 12 x 23 x 21 18 (Diam.) x 37 12 x 23 x 21 18 (Diam.) x 37 .. T T M M Nickel plated Nickel plated Nickel plated ' Nickel plated ..... ' ,. . .' t ~ , '.. M . .2400 3400 2600 3700 400 430 For restaurant appliances, miscellaneous electrical and miscellaneous gas burning appliances. . k When these appliances are hooded and provided with adequate exhaust, use 60 percent of recommended rate of heat gain from unhooded appliances. 1600 2300 2600 3700 ' -4000 5700 5200 7400 500 800 1150 1600 O ^ T a b l e 29. R a te of H e a t G a in F ro m A p p lia n c e s W IT H O U T HOODS" (C o ncluded) H air Dryer. Blower Type H air Dryer, Helmet T y p e , Permanent Wave Machine Neon Sign, per linear ft of tube Steriliser, Instrument 1 Burners, Laboratory Small Bunsen Small Bunsen Fishtail Fishtail Large Bunsen Cigar Lighter j H air Dryer. 5 helmets Stoves. Oven 306 fOt'Do QCQ U2 aUM{H<w iSSSS: * 7200 1 1800 1 9000 9200 ; 2300 j 11500 CHAPTER 12 2700 8 8 oo * 2 88 . 800 -8 8co . 1200 1870 . 160 2300 88 ;* * 1952 Guide 1 1000 4000 - 19000 oPCS0o-ko0oOO5oC0-J > ooooo: vroo O O .- . ooCOoonCOooCnOoon00non>o o S' 15000 83080 .. 1 2500 | 33000 25000 1 25000 | 5400 2400 3750 0009 igOtt o 8 oNto 8*Q ' 60 heaters at 25 w each, 36 in normal use ; Q 1 -mz 3H S5 8 S oil pi S!1 2 An 2 3 Sg o-JaSgSiZ2 d<S"3XQ|Sg o|"K On Pan, 165 w; Low, 915 w; High, 1580 w 8*g2*; gif SdBd *a0t*a0t 3o5 3Po ii 22 .< For physicians: thermo stat cuts off 550 w , before boiling - 1100 Manufactured Gas Natural Gas - Manufactured Gas , Natural Gas ' Adjustable orifice | Continuous Flame | Heater and fan blowing air to helmets . Insulated, modern N ot Insulated 0H08n080n4i8o08o 22222 2 < :i?l!| ed fl a Si CQEQttmS 333.23 SSSSx sa ea s A- & - .w ,fr AI3 s3 3.3 8S 5=3Sa! .3 a) s*s 1? *52 3*0 *53 |8 3 f nS 38 i U<3 a l e. C c9 fi S SSr8S <5.0 Cooling Load 307 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 $ 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 29 presents, recommended data.28 Note that the maintaining rate in Table 29 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 29. 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 no 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 con ditioned. The same effectiveness of the hood should be figured for both latent and sensible heat. LOAD FROM MOISTURE TRANSFER THROUGH PERMEABLE BUILDING MATERIALS The diffusion of moisture through all common building materials is a natural phenomenon which is always present to a greater or lesser degree. The permeability values for various building materials are given in Table 22 of Chapter 9, together with an explanation of moisture transmission through these materials. In the usual comfort air-conditioning application, it is common practice to neglect moisture transfer through walls, for the actual rate is quite small and the corresponding latent-heat load is hardly significant. So-called vapor barriers are frequently employed in modern construction for the pur- . pose of keeping moisture transfer to a minimum, and reducing the de teriorating and insulation-destroying effects of moisture. ' Industrial jobs, on the other hand, frequently call for a low moisture content to be maintained in a conditioned space. Here the matter of moisture transfer cannot be 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. The equation for computing this load is: M / Vapor Pressure \ 7000 \ Difference, In. Hg/ * 1076, Btu per (hr) (sq ft) (17) where it = permeability grains per (sq ft) (hr) (in. Hg). 7000 grains per pound. 308 CHAPTER 12 1952 Guide - The factor 1076 is defined in list of symbols at Equation 14. (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. JWhen 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 from 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 lump- these factors together and combine them with a safety factor according to the experience and judgment of the estimator. On this basis, a small safety factor is added to the calculated cooling load to com pensate for miscellaneous effects. No'rules can be given for this procedure, as experience in air conditioning is indispensable for application of suitable safety factors. . REQUIRED AIR QUANTITY THROUGH CONDITIONING EQUIPMENT 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; and to refer to the section on Apparatus Dew-Point in Chap ter 29. 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 quantity 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: : 1. Determine the total sensible and latent heat loads in Btu per hour for the space. ,..... 2. Compute the quantity called the enthalpy-humidity difference ratio (also referred to as heat-moisture ratio) of the room load, jr.------tjj-. Use the equation: rr i -- W .. I. A ?; * 'A- I v I i A ,1 Cooling Load 309 hi -- ft. (Space sensible load + space latent load) W i -- W, = Space latent load/1076 where h, = enthalpy of moist air supplied to the space, Btu per pound of dry air. hi = enthalpy of moist air at room design conditions^ Btu per pound of dry ' ' air. . . .. ..... ' ' .humidity ratio of moist air supplied to the space, pounds of vapor per pound of dry air.) ' - Wi = 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 of water vapor removal in pounds per hour. If the rate of water removed is known, it may be used directly in Equation 18. - 3. Draw a line through the reference point on the A.S.H.V.E. psychrometric chart and the value of (A, -- h,)/(Wi -- .1V,) determined above. Draw a second line through the state point of the room air' (design wet-bulb and dry-bulb temperatures) parallel to this line. This is the condition line for the process. ' 4. Read the t,emperature where the condition line from step 3 intersects the satura tion line. This is called the apparatus dew-point. 5. Compute the required air quantity from the relation . (Space sensible load) Space \ /Apparatus V] Coil V (19) Kdry-bulb/ \dew-point/J * efficiency / The magnituderof Qn 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 (1----0- '00923X 1-08, assuming an average supply air dew-point of 55 F. Since standard air density (0.075) includes the weight of the water vapor, it is desirable to reduce it to the basis of dry air by the last factor where 0.00923 = humidity ratio of air at 55 F dew-point, and 0.62 =* ratio of density of water vapor to dry air at same temperature and pressure. Refer to Chapter 35 for coil selection. - Note that the product [(space dry-bulb) -- (apparatus dew-point)] X (coil effi ciency) is equal to the dry-bulb range through which the conditioned air is cooled. Hence, inVare 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 efficiency is specified accordingly on the proper basis. MINIMUM ENTERING AIR TEMPERATURE Due consideration must be given to the temperature of the air entering the conditioned space in order to prevent objectionable drafts. With ceil ing type diffusers or wall grilles with a high aspect ratio (see Chapter 30), many engineers consider 20 deg as the maximum difference for good design under average conditions. This difference can only be exceeded with ex tremely high ceiling outlets or wall grilles. Thus, if 80 F dry-bulb is to be maintained in a space with average ceiling height, the minimum delivered air temperature would be limited to about 60 F diy-bulb temperature. If the'latent heat load is relatively high, it is often necessary to circulate more air with a higher delivered dry-bulb temperature in order to produce a thermodynamic balance. If the dry-bulb temperature of the air supplied to the space is known, the required air quantity can be calcuated from the formula, , g.: Qn, 1.08 (ti - O (20) 310 CHAPTER 12 1952 Guide or the supply temperature U can be determined as follows, t. h - ft 1.08 x Qi. . (21) EXAMPLE--COOLING LOAD CALCULATION --An effective means of summarizing the calculation procedure will be the use of an illustrative example. While condensed calculation forms are commonly employed for work of this nature, an outline will be used here in order to facilitate explanatory comments. , Example 18: A one-story office building Fig. 6 is located in an eastern state near 40 deg latitude. The adjoining buildings on the north and west are not conditioned, and the air temperature within them is known to be substantially equal to the outdoor air temperature at any time of the day. South wall construction: 8 in. concrete block, 4 in. brick veneer, i in. plaster on walls. (Table 9, Chapter 9, No. 92B, U -- 0.41.) East wall and outside north wall construction: 8 in. concrete block, painted white, J in. plaster on walls. (Table 8, Chapter 9, No. 82B, V = 0.52.) West wall and adjoining) north party wall construction: 13 in. solid brick, no plaster: i = --+-- +-- or, U = 0.263. Use U = 0.26. U 1.65 5 1.65 , Roof construction: 2J in. flat roof deck of 2 in. gypsum fiber concrete on gypsum board surfaced with built-up roofing. (Table 14, U = 0.34 for summer.) 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 in. reveal on all windows. . Front doors: Two 2 ft-6 in. x 7 ft (glass panels). Side doors: Two 2 ft-6 in. x 7 ft (i 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; A0 = 41.38 Btu per lb dry air. Indoor design conditions: Dry-bulb 80 F, wet-bulb 65 F; Wi = 0.0098 lb vapor per lb dry air; Ai = 29.95 Btu per lb dry air. Cooling Load 311 Occupancy: 85 office workers. , Lights: 12,000 watts, fluorescent; 4000 watts tungsten. ' Fan motor: 7J hp. Conditioning equipment to be located in adjoining structure to north. . Find : Total, sensible, and latent maximum cooling loads and required air quantity through conditioning equipment. Solution: From Table 4, the recommended ventilation rate is 15 cfm per person. Total necessary = 85 X 15 = 1275 cfm or 76,500 cu ft per hr. ' As the room volume is 40,000 cu ft, the air changes per hour will be 76;500/40,000 = 1.91 which is more than one air change. . Estimated Time of Maximum Cooling Load: For this job, judgment indicates that the roof will make the greatest single 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 12 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 plm. Examination of Table 16 (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 Blightly 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. Heal Gain Through Outer WaU and Roof Areas: From Table 13 the temperature differential for the south wall (8 in. concrete block with 4 in. brick veneer) may be about the same as a 12 in. brick which is 6 deg at 3:00 p.m. for a dark colored wall. From the same table, the temperature differential for the east wall (8 in. concrete block with plaster) will be 11 deg at 3:00 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 pun. (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 13) 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 -- f.) = 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 Hbat 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 6 11 3 2 15 0.34 0.41 0.52 0.52 0.26 0.59 72,000 995 4,380. 265 550 310 Total...................... ..................... .................. .. 78,500 * Calculated from gross wall area, less windows and doors. 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 16 and 17 will give the total heat gain from the glass areas. The window reveals will shade the south windows; the fraction of the window area receiving direct radiation is obtained from Equation 10 by substituting values as follows: , n = s/l = 4/60; rj = 4/36; 0 = 45.5 deg, tan 0 = 1.02 y = 74 deg, tan y = 3.487, cos y = 0.276 . 312 CHAPTER 12 J952 Guide r _ i (1M.\ _ i f34im . (\ (l-O2) (3.487) = A . Gt ~ 60 VO.276/ 36 (3`^87) + \60y \36/ ; 0.276 ' The south doors will be considered entirely sunlit. The outdoor air temperature is 95 F at 3:00 p.m. From Table.27 the inside Venetian blind factor is 0.74. The instantaneous heat gains due to transmitted direct and diffuse solar radiation, and from convection and radiation gain, are found in Tables 16 and 17 as listed below' for the south facing doors and windows',. the north facing windows and the 1 glass - doors in the east wall. The gain through the solid portion of the east doors may be approximated by use of Fig. 4, since the wood panels have'little heat capacity. From Table 5 the diffuse radiation value is taken as 18 Btu per (hr)(sq ft) from which to + is found to be 98.2 for a = 0.7 and fm =' 4.0. From Fig. 4, g = 27.0 Btu per (hr) (sq ft). These heat gains are itemized in the following table (note the corrections for difference between 80 F indoor design temperature and the 75 F design temperature used in Table 17). .... ............: Location South WindowB South' Doors East DooreJGlass \Wood North Windows Total . Area Sq Ft Frac tion Sunlit Shade Factor Trans Solar Gain Btu/ (hr) (8Q it) CORR from Gonv and Rad Gain 75F to 80F - Indoor Btu/ (hr) Temper (sqft) ature Btu/(hr) (sqft) Total Gain Btu/ (hr) (sqft) Total Gain, ; Btu/hr- .. 6b 35 18 18 30 0.462 1.00 -- -- -- 0.7i -- -- -- -- 14 42 14 -- 24 --5 33 1980 . 24 -5 61 2135 22 -5 31 ' 560- 27 -5 22 395 22 --5 . 32 . k 960 . 6030 In some jobs it would be desirable to increase (or decrease) the instantaneous radi ation heat 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. i- . Heat Gain from Ventilation and Infiltration: . 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 + 67 = 1342 cfm. The sensible, latent and total loads are determined from Equations 12,13, and 14, respectively, at 3:00 p.m. (Table 11) U = 95, ti = 80, Wo = 0.0169, IFi = 0.0098. All the air entering the room as infiltration becomes a part of the space load. ' Infiltration: g. = 67 X 1.08 (95-- 80) = 1085 Btuh, sensible. g. = 67 X 4840 (0.0169-0.0098) = 2300 Btuh, latent. St = q. + 8. = 1085 + 2300 = 3385 Btuh, total. Ventilation Air Taken through Cooling Unit Which Does Not Become a Part of the Space Load: . g, .= 1275 X 1.08 (95^80) = 20,700 Btuh, sensible. 8. = 1275 X 4840 (0.0169-0.0098) = 43,800 Btuh, latent. , St = S. + 8. = 20,700 + 43,800 = 64,500 Btuh, total. Cooling Load 313 Heat Gain from Sources within the Conditioned Space: . For the occupants, use the data of Table 28 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 allowance factor of 1.20 for the fluorescents and of unity for the tungsten globes. S.i = (12,000 X 1.20 + 4000) X 3.41 = 62,700 Btu per hr. " For the fan motor, use Equation 16 with a load factor of unity, and omit term Motor Efficiency because the motor is not within the space. ' 8m = 7.5 X 2544 = 19,100 Btu per hr. Moisture Permeation, Miscellaneous Allowance, and the Load-Lag Estimate: Moisture permeation will be negligible, since this is a 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 that no adjustment for load-lag need be made to the load as computed. (Refer to Fig. 5). 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 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 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:' The total loads are summarized in Table 30. ' '1 " ' Compute the enthalpy difference ratio from Equation 18. ' . . hj -- h, Wi-W, (184,415 + 23,550) X 1076 = 9500. 23,550 Table 30. Summaby op Total Loads--Example 18 \ Load Component . Sensible Btu/hr Latent Btu/hr All walls, roof and doors.............................................. Glass areas.............................................................................. Infiltration 67 cfm........................................................... Occupants........................ ......................... Lighting.................................. ................................... Motor, fan......... 78,500 6,030 1,085 17,000 62,700 19,100 Space Tioad . 184,415 Ventilation 1275 cfm... Totals................. ...................... 20,700 205,115 Grand Total Sensible and Latent. ^.................................................................. 2^300 21,250 23,550 43,800 67,350 ' 272,465 " From the A.S.H.V.E. psychrometric chart, determine that the apparatus dew point is 54.6 F (refer to Chapters 3 and 29). . . 1 computing the effective air quantity, assume a coil efficiency of 85 percent. 7900 cfm. 1.08 (80 - 54.6) X 0.85 314 CHAPTER 12 1952 Guide (Refer to Chapter 35 for coil selection and efficiency.) - ' From note under.Equation 19 the dry-bulb range will be (80 -- 54.6) X 0.85 -- .21.6 deg, and the dry-bulb temperature of air leaving the coil will be 80 -- 21.6 = 58.4 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 21): .- 184,415 - 19,100 1.08 X 7900 80 - 19.4 = 60.6 F. With good distribution and diffusion, this temperature should not produce objec tionable drafts. Example 18: Summary Outdoor Conditions.............................95 DB Space Conditions..................................80 DB 78 WB 65 WB 0.0169 Humidity Ratio 0.0098 Humidity Ratio Difference................................15 . 0.0071 . Sensible Load Transmission . ' Btu/Hr Roof 4000 sq ft X 53 X 0.34 =............................................... .................. 72,000 S Will 4ns an ft. y 6 y 0 41 -- .......................................... .................. 995 E. Wall 765 sq ft X 11 X 0.52 =........................................... ................... 4,380 iq tyHn f.y I7n sq ft. y 3 y o 52 --..................................... .................. 265 N AW Partv Wall Wfi5 an ft. y 2 y 0 26 -- ................ .................. 550 Floor None Tlrtrxr U onft YISYO.W- ............................. .................. 310 All Glass and Rest of Doors =................................................ ................... 3,020 Solar Radiation S. Glass 60 sq ft X 14 =..................... S. Glass (Doors) 35 sq ft X 42 =..... E. Glass (Doors) 18 sq ft X 14 =--N. Glass 30 sq ft X 15 =.................... 840 1,470 250 450 Internal Load Infiltration 67 cfm X 1.08 X 15 = ... Lights (12,000 X 1.20 + 4000) 3.41 = People 85 X 200 =................................. Motor, Fan 7.5 hp X 2544 =................ 1,085 62,700 17,000 19,100 Total Sensible Space Load-- 184,415 Latent Load Infiltration 67 cfm X 4840 X 0.0071 = People 85 X 250=...................................... Total Latent Space Load 2,300 21,250 23,550 Ventilation Air Sensible 1275 cfm X 1.08 X 15" =... Latent 1275 cfm X 4840 X 0.0071 =.' 20,700 43,800 Grand Total Load 272,465 LETTER SYMBOLS USED IN CHAPTER 12' a = fraction of incident solar radiation absorbed, dimensionless; subscripts D, d, t refer to direct, diffuse and total, respectively. 0 = solar altitude, degrees. y = wall solar azimuth, degrees. e = emissivity, dimensionless. . e = incident angle, degrees. X = amplitude decrement factor, dimensionless. f, = permeability to moisture transmission, grains per (square foot) (hour) (inch mercury). Cooling Load 315 r = fraction of incident solar radiation transmitted, dimensionless. Subscripts D, d, t refer to direct, diffuse and total, respectively. <t> = solar azimuth, degrees. .. & = wall azimuth, degrees. A = area across which heat is being transferred, square feet. . $ = unit surface conductance, Btu per (hour) (square foot) (Fahrenheit degree). ' Subscripts c, r, o, and i refer to convection, radiation, outdoor, and indoor, . respectively. , Gt -- fraction of total window area receiving direct solar radiation when shaded by window reveal, dimensionless. h = enthalpy of air per pound of dry air, Btu per pound. Subscripts i, o, and s refer to indoor, outdoor, and supply air, respectively. I = incident solar radiation, Btu per (hour)' (square foot). Subscripts D, d, Dn, and t refer to direct, diffuse, direct normal arid total solar radiation, respectively. K = cosine of angle of incidence for direct solar radiation striking a surface, dimen sionless. k = thermal conductivity of building material, Btu per (square foot) (hour) (Fahrenheit degree per inch). L = thickness of building material, inches. I = height of window, feet. Q = rate of entry of outdoor air, cubic feet per minute. Qr = required air quantity through conditioning equipment, cubic feet per minute. q = instantaneous rate of heat transfer, Btu per hour. 9e = instantaneous latent heat load, Btu per hour. 1 = latent heat load due to moisture transmission through materials, Btu per (hr) (sq ft). q, = instantaneous sensible heat load, Btu per hour. . ?t = ? + Btu per hour. . ' R, = low temperature radiant energy received from outdoor surroundings (does not include solar radiation), Btu per (hr) (sq ft of receiving surface). R = radiant energy emitted by a black body, Btu per (hr) (sq ft).. ' Subscripts go and L refer to outdoor surfaces of glass and building, respec tively. ., S = rate of heat storage within a glass section, Btu per (hr)(sq ft).' < = sol-air temperature, Fahrenheit degrees. <* = 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, Fahren heit degrees. Iti = temperature of indoor glass surface, Fahrenheit degrees. Ito = temperature of outdoor glass surface, Fahrenheit degrees. ' ti = indoor air temperature, Fahrenheit degrees. in = temperature of outer surface of building, Fahrenheit degrees. . fm = 24-hr cyclic average sol-air temperature, Fahrenheit degrees. lo.= outdoor air temperature, Fahrenheit degrees. ip = <m + (f* -- <m), net equivalent outdoor temperature for combined periodic and mean heat flow, Fahrenheit degrees, i. = room supply air dry-bulb temperature, Fahrenheit degrees. U = overall coefficient of heat transfer of a structural seotion, Btu per (square foot) (hour) (Fahrenheit degree). o = volume of outdoor air per pound of dry air, cubic feet. u> = 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. 316 CHAPTER 12 1952 Guide REFERENCES ` 1 Application Engineering Standards for Air Conditioning for Comfort (Air Conditioning and Refrigerat ing Machinery Association, Inc., 1947, pp. 4-7). " - '- Proposed Standard Solar Radiation Curves for Engineering Use, by P. Moon (Journal of the Franklin Institute, November 1940, Vol. 230, No. 5, pp. 533-617). *. A.S.H.VJ3. Research Report No. 1268--Summer Weather Data and Sol-Air Temperature^--Study of Data fpr 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 Yprk City, by C. O. Mackey and'E. B. Watson (AJ3.H.V.E. Transactions, Vol. 51, 1945, p. 75). ` ` . Summer Cooling for Comfort as Affected by Solar Radiation, by G. A. Hendnkson' and J. H. Walker (Heating and Ventilating, Vol. 29, No. 11, November 1932, pp. 14-21). . .\ Tables of Computed Altitude and Aaimuth (U. S. Navy Dept. Hydrographic Office Bulletin No. 214, Vols. 1-9, Washington, D. C,, 1940). i The American Nautical Almanac (U. S. Naval Observatory, Washington; D. C., annual). - TheEffectof Solar Radiation on the Heat Transmission Through Walls, by F. C. Houghten, Carl Gutberlet and A. A. Rosenburg (American Society of Testing Materials Symposium on Thermal Insulating Materials, Philadelphia, 1939). .; A.S.H.V.E. Research Report No. 1157--Summer Cooling Load as Affected by Heat Gain Through Dry, Sprinkled and Water Covered Roofs, by F. C. Houghten, H. T. Olson and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 46, 1940). .. n Radiation in the Atmosphere, by D. Brunt (Supplement to the Quarterly Journal of the Royal Mete orological Society, Vol. 66,1940). ` `' ' ' ' u 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.V.EL Trans actions, Vol. 38, 1932, p/ 231); Effect of Heat Storage and Variation in Outdoor Temperature and Solar Intensity on Heat Transfer Through Walls, by J. S. Alford, J. E. Ryan and F. O. Urban (A.S.H.V.. Trans^ actions Vol. 45, 1939, p. 369). Periodic Heat Flow in Building Walls Determined by Electrical An alogy Method, by Victor Paschkia (A.S.H.VJE. Transactions, Vol. 48, 1942, p. 75).--Periodic Heat Row- Homogeneous Walls or Roofs, by C. O. Mackey and L. T. Wright, Jr. (A.S.H.V.E. Transactions, Vol. 50. 1944 p. 293). Periodic Heat Row--Composite Walls or Roofs, by C. O. Mackey and L. T; Wright, Jr (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.VJ3. Journal Section, Heating, Piping and Air Conditioning May 1948. p. 121). . ss Solar Gain Through Walls and Roofs for Cooling Load Calculations, by J. P. Stewart (A.S.H.VE. Journal Section, Heating, Piping and Air Conditioning, August 1948, p. 121). n A S.H.V.E. Research Report No. 1002--Cooling Requirements of Single Rooms in a Modern Office Building, by F. C. Houghten, Carl Gutberlet, and Albert J. Wahl (A.S.H.V.E. Transactions, Vol. 41,1935, p. 53). `' u Study oi Actual vb. Predicted Cooling Load on An Air Conditioning System, by James N. Livermore (A.S.H.V-E. Transactions, Vol. 49, 1943, p. 287). . u A.S.H.V.E. Research Report No. 1195--Heat Gain Through Walls and Roofs as Affected by Solar Radiation, by F. C. Houghten, E. C. H&ch, S. I. Taimuty and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 91). . it A 8.H.VJE. Research Report--Measurements of Solar Heat Transmission Through Rat Glass, by G. V. Parmelee, W. W. Aubele and R. G. Huebecher (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, Vol 20, No. 1, January 1948, p. 158). . n A.S.H.V,F Research Report--Solar and Total Heat Gain Through Double Flat Glass, by G. V. Parmelee and W. W. Aubele (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, Vol. 20, No. 6, June 1948, p. 116). u A.B.H.V.E. Research Report--Solar Energy Transmittance of Eigbt-Incb Hollow Glass Block, by G. V. Parmelee and W. W. Aubele (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, Vol. 21, No. 9, September 1949. p. 111). ti a S.H.V.E. Research Report--Heat Row Through Unshaded Glass: Design Data for Use in Load Calculations, by G. V. Parmelee and W. W. Aubele (A.S.H.VJ2. Journal Section, Heating; Piping andAir Conditioning, June 1950, p. 123). . A.8.H.V.E. Research Report--Solar Energy Transfmittaiice of Figured Rolled'Glass, by G. V. Parmelee and W. W. Aubele (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, Vol.23, No. 2, February 1951, p. 124). . a S.H.V.E. Research Report No. 975--Studies of Solar Radiation Through Bare and Shaded Win dows by F. C. Houghten, Carl Gutberlet and J. L. Blackshaw (A.S.H.VJ). Transactions, Vol. 40, 1934, p. 101). . A.S.H.VJ3. Research Report No. 1180--Heat Gain Through Western Windows With and Without Shading, by F. C. Houghten Mid David Shore (A.S.H.V.E. Transactions, Vol. 47,1941, p. 251). . a The Mechanism of Heat Transfer, Panel Cooling and Heat Storage, Part II: Solar Radiation, by C. S. Leopold (Refrigerating Engineering, June 1948, p. 571). ; M The Mechanism of Heat Transfer, Panel Cooling, Heat Storage, by C. S. Leopold (Refrigerating Engi- neefing, July 1947, p. 33). Hydraulic Analogue for the Solution of Problems of Thermal Storage, Radiation, Convection and Conduction, by C. S. Leopold. (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, July 1948, p. 105). ' t Heat Gains Are Not Cooling Loads, by C. O. Mackey and N. R. Gay (AJ3.H.VJ2. Journal Section, Heating, Piping and Air Conditioning, August 1949, p. 105). * See Reference 1, p. 8. . s Cooler Footcandlesfor Ait Conditioning, by W. G. Darley (A.S.H.V.E. Transaction, Vol. 46,1940, p. 387) Lighting and Air Conditioning Design Factors, Report of IJBJd.--A.S.H.VJS. Joint Committee on Lighting andAir Conditioning (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, Septembr 1941, p. 605). Lighting and Air Conditioning, by Howard M. Sharp (Heating and Ventilating, No vember 1942, p. 35). :- a Compiled by J. P. Stewart from various sources. *4t CHAPTER 13 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 not attained wide-spread usage as yet. The choice of fuel is usually based on dependability, cleanliness, availability, economy, operating requirements, and control. Analysis of Fuels SOLID FUELS Goal 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 requites considerable space; a treatment applicable to . heating boilers is given in a Siireau of Mines Bulletin.1 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. This 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 of1 a sample of coal when dried at about 220 F. To determine the volatile matter, the dried sample is heated to about 1750 F in a closed crucible, and the loss of weight is noted. The remaining sample, is then burned in an open crucible, and the accompanying loss of weight represents the fixed carbon. The unbumed residue is ash. Although detennined separately, the sulfur content is frequently reported with the proxiihate analysis be cause the usefulness of a coal for certain purposes depends on its sulfur content. '. In the ultimate analysis, which is difficult to make, the percentages of carbon, hydrogen, oxygen, nitrogen, sulfur, and ash in the coal sample are determined. It is used for detailed studies of fuels, and in computing 317 318 CI H^APTER 13 1952 Guide 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.* 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 Btu pxb Lb ' Constituents, Per Cert Rare Moist, Mineralmatter- free Moist, as Received Oxygen Hrdrogen Carbon Nitrogen Sulfur Anthracite___ _ .-- 14,600 12,910 5.0 2.9 80.0 0.9 0.7 Semi-Anthracite------------ 15,200 13,770 5.0 3.9 80.4 1.1 1.1 Low-Volatile Bituminous---------------- 15,350 14,340 5.0 4.7 81.7 1.4 1.2 Medium-Volatile Bituminous............. _ 15,200 13,840 5.0 5.0 79.0 1.4 1.5 High-Volatile Bituminous A________ 14,500 13,090 9.2 5.3 73.2 1.5 2.0 High-Volatile -. Bituminous B -- . 13,500 12,130 13.8 5.5 68.0 1.4 2.1 High-Volatile Bituminous C..---------- 12,000 10,750 21.0 5.8 60.6 1.1 2.1 Sub Bituminous B. __ 10,250 9,150 29.5 6.2 52.5 1.0 1.0 Sub Bituminous C-------- 9,000 8,940 35.8 6.5 46.7 0.8 0.6 Lignite- _______ _ 7,500 6,900 44.0 6.9 40.1 0.7 1.0 Awh 10.5 8.5 6.0 8.1 8.8 9.2 9.4 9.8 9.8 7.3 ft+ Br c 87.9 89.3 , 91.4 89.0 87.7 87.3 87.4 88.2 89.0 91.0 * (Btu as received) X 100 + (100 - 1.1 Ash) coals and in lignite. The percentage of ash and its fusion temperature do . not indicate the composition or distribution of its constituents. Classification of Coals ' A classification of coals is given in Table 2, and a brief description of the kinds of fuel is given in the following paragraphs, but it should be recog nized that there are no distinct lines of demarcation between the kinds, and that they graduate into each other. Anthracite is a clean, dense, hard coal which creates little dust in handling. It is comparatively hard to ignite, but it bums freely when well started. It is non-caking, it burns uniformly and smokelessly with a short flame, and it requires no attention to the fuel bed between firings. It is capable of giving a high efficiency in the common 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 specifi cations are shown in Table 3. :' Semi-anthracite has a higher volatile content than anthracite. It is not so hard, and ignites somewhat more easily. Otherwise their properties are similar. Semi-bituminous coal is soft and friable, and fines and dust are created by handling it. It ignites somewhat slowly and burns with a medium length of flame. Its caking properties increase as the volatile matter increases, but the coke formed is relatively weak. Having only half the volatile matter content of the bituminous coals, it can. be burned with less production of smoke, and is sometimes called a smokeless coal. Fuels and Combustion 319 The term bituminous coal covers a large range of coals and includes many types having distinctly different composition, properties, and burning characteristics! The coals range from the high-grade bituminous coals of the East to the poorer coals of the West. Their caking properties range from coals which melt completely, to those from which the volatiles and tars are distilled without change of form, so that they are classed as non-caking or free-burning. Most bituminous coals are strong Table 2. Classification of Coals by Rank0 l^6&d: F.C. Fixed Carbon. V.M. TM Volatile Matter. Btu = British thermal units. Class Group Limits of Fixed Carbon os Btu Mineral-Matter- Free Basis R EQUTBITE'PHYSICAL Properties I. Anthracite. U. Bituminous*. HI Sub-bitumi nous IV. Lignitic. Meta-anthracite Dry F.C., 98 per cent or more (Dry V.M., 2 per cent or less) Anthracite Dry F.C., 92 per cent or more and less than 98 per cent (Dry V.M., 8 per cent or less and more than 2 per cent) Semi-anthracite Dry F.C., 86 per cent or more arid less than 92 per cent (Dry V.M., 14 per cent or less and more 1. Low volatile bituminous coal... than 8 per cent) Dry F.C., 78 per cent or more and less than 86 per cent (Dry V.M., 22 per cent or less and more than 14 per cent) Medium volatile bituminous Dry F.C., 69 per cent or coal . more and less than 78 per cent (Dry V.M.. 81 per cent or less and more than 22 per cent) High volatile A bituminous coal 4. High volatile B bituminous coal 5. High volatile C bituminous Coal 1. Sub-bituminous A coal. Sub4>ituminous B coal. Dry F.C., less than 69 per cent (Dry V.M , more than 31 per cent); and moist0 Btu, 14,000 or more Moist0 Btu, 13,000 or more and less than 14.OOO0 Moist Btu, 11,000 or more and less than 13.OOO0 Moist Btu, 11,000 or more and less than 13,000 Moist Btu, 9500 or more and less than 11,000 Sub-bituminous C coal. Lignite............................ Brown ooal..................... Moist Btu, 8300 or more and less than 9500 ' Moist'Btu less than 8300 Moist Btu less than 8300 Non-agglomerating Either agglomerat ing or nonweathering/ Both weathering and non-agglomerat ing Consolidated Unconsolidated w ckssification does not include a few coals which have unusual physical and chemical properties ppd which come within the limits of fixed carbon or Btu of the high-volatile bituminous and sub-bituminous rankB. All of these coals either contain less than 48 percent dry, mineral-matter-free fixed carbon, or have more than 15,500 moist, mineral-matter-free Btu. ' e If agglomerating, classify in low-volatile group of the bituminous ' 1. , Moist Btu refera to ooal containing its natural bed moisture but not including visible water on the surface of the coal. ' I* recognised that there may be non-caking varieties in each group of the bituminous Coals haying K) percent or more fixed carbon on the dry, mineral-matter-free basis shall , be classified according to fixed carbon, regardless of Btu. , There are three varieties of coal in the high-volatile C bituminous coal group, namely. Variety 1, agglom erating and non-weathering; Variety 2, agglomerating and weathering; Variety 3, nniwtgglnnwfcinff and non-weathering. . Adapted from AJS.T.M. Standards, 1937, Supplement, p. 145, American Society for Testing Materials. and non-friable enough to permit the screened'sizes being delivered free from fines. In general, they ignite easily and burn freely; the length of flame varies with different coals, but it is long. Much smoke and soot are possible, if improperly fired, especially at low rates of burning. Sub-bituminous coals occur in the western states; they are high in moisture when i*11?! a to break up as they dry or when exposed to the weather; they are to ignite spontaneously when piled or stored. They ignite easily and quickly, and haye a medium length flame; are non-caking and free-burning; the lumps tend to break into small pieces if poked; very little smoke and soot are formed. bignite is of woody structure, very high in moisture as mined, and of low heating 320 CHAPTER 13 1952 Guide ' value; it is clean to handle. It has a greater tendency than the sub-bituminous coals to disintegrate as it dries, and it also is more liable to spontaneous ignition. Freshly ' mined lignite, because of its high moisture, ignites slowly. It is non-caking. The char left.after the moisttore and volatile matter are driven.off burns very easily, like charcoal. The lumps tend to break up in the fuel bed, and pieces of char falling into the ashpit continue to bum: Very little smoke or soot is formed. . Dustless Treatment In order to allay the dust, the more friable coals are sometimes sprayed with various petroleum products such as a solution of calcium chloride, or a mixture 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 Table 3. Standaed Anthracite Specifications* Test Mesh Bound . Si2B of Coal Through In. Broken................... Egg.......................... Stove....................... Nut......................... Pea.......................... No. 4' ................... m 3M to 3 2He 1H 'Ms Mo Ms Ms H Over In. 3M to 3 2Ms 1W *Ms Ms Ms Ms H* Oversize Max. % _ 5 m m 10 10 10 10 20 Undersize . Max. % Min. % 15 m 15 m 15 m 15 m 15 m 15 7H 17 7M 20 10 20 10 ' Maximum Impurities Slateb % Boneb % or Ash0 % 2 m2 23 34 45 11 11 11 11 12 15 16 * Approved and adopted, effective July 28, 1947, by the Anthracite Committee (Manual of Statistical Information, Anthracite Institute). . b When date content in the sizes from Broken to Nut inclusive is less than above standards, bone content may be increased by one and one-half times the decrease in the slate content under the allowable limits, but slate content specified above shall not be exceeded in any event. e Ash determinations are on a dry basis. - ' * A tolerance of 1 percent is allowed on the maximum percentage of undersize and the maximum percentage of ash content. The maximum percentage of undersize is applicable only to anthracite as it is produced at the preparation plant. . Sate is defined as any material which has less than 40 percent of fixed carbon. Bone is defined as any material which has 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 qt 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 Coke is produced by the distillation of the volatilematter from coal. The type of 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.bven. Coke is also produced as a residue from the destructive distillation of oil. . .. ; High-temperature cokes. Coke,, as usually available, is of the high-temperature type, and contains between 1 and 2 percent volatile matter. High-temperature cokes are subdivided into beehive coke of which comparatively little is now sold for domestic use, by-product coke, which covers the greater part of the coke sold, and gas-house coke. The differences among these three cokes are relatively small; their denseness and hardness decrease and friability increases in the order named. In general, the lighter and more friable cokes ignite and burn more readily. : Low-temperature cokes are produced at low coking temperatures, and only a portion of the volatile matter is distilled off. Cokes, as made by various processes under.de velopment, have contained from 10 to 15 percent volatile matter. In general, these cokes ignite and burn more readily than high-temperature cokes. The properties of various low-temperature cokes may differ more than those of the various high-tem Fuels and Combustion 321 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 tp shake the. grates only until the first bright.?dais 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 ;iti is<at least level with the sill of the fire-door. .. Aisatisfactory. methodt-of firing pea coal consists of drawing the red coals toward the front end, and piling fresh fuel toward the back;of the firebox. -* - .. - Peat 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 bum 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 grates, this fuel can be burned satisfactorily without the aid of any special equipment, except small mesh grates. In general, it will be found more satisfactory with 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 form low fire will minimize the clinker formation and keep any clinker formed in an easily broken up condition so that it re&dily can be shaken through the grate. Forced draft and small mesh grates or, for greater convenience, domestic stokers are frequently used. Buckwheat anthracite No. 2, or rice size, is used, principally in stokers 322 CHAPTER 13 1952 Guide of the domestic, commercial and industrial type. No. 3 buckwheat anthra cite, or barley, has no application in domestic heating. ' Firing Methods for Bituminous Coal A commonly recommended procedure for firing domestic heating units, called the side-bank method, requires the movement of live coals to one side or the back of the grate, and placing the fresh fuel charge on the opposite side. The results are a more uniform release of volatile gases, and the subjection of these gases to the high temperature of the red 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' should never be fired over the entire fuel bed at one time. A portion of the glowing fuel should always be left exposed to ignite the gases leaving the fresh charge. The importance of firing bituminous coal in small quantities at short intervals is discussed in a U. S. Bureau of Mines technical paper.1 Better combustion is obtained by this method in that the fuel supply is main tained more nearly proportional to the air supply. ' If the coal is of the caking kind, the fresh charge will fuse into one solid mass which can be broken up with the stoking bar and leveled from 20 min to one hour after firing, depending on the temperature of the firebox. Care should be exercised when stokmg not to bring the bar up to the surface of the fuel, as this will tend to bring ash into the high temperature 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 raised only enough to break up the fuel. With fuels requiring stoking it may not be necessary to shake the grates, as the ash is usually dislodged during stoking. It is acknowledged that it may be difficult to apply the outlined methods to domestic heating boilers of small size, especially when frequent attendance is impracticable. The adherence to these methods insofar as practicable, however, will result in better combustion. ' The output obtained from any heater with bituminous coal will usually exceed that obtained with anthracite, since bituminous coal bums more rapidly than anthracite, and with less draft. Bituminous coal, however, will usually require frequent attention to the fuel bed. . Preventing Smoke In general, time, temperature and turbulence are the essential require 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. Checker or alternate firing, in which the fuel is fired alternately on 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 door and the coke pushed back into the furnace just before firing again, pro- . duces the same effect. The volatiles as they are distilled thus have to pass over the hot fuel bed where they will be burned if they are mixed with sufficient air, and are not cooled too quickly by the heat-absorbing surfaces of the boiler. .' Steam or compressed air jets, admitted over the fire, create turbulence in the furnace and bring the volatiles of the fuel more quickly into contact Fuels and Combustion 323 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.7, 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 modem 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. Modem boiler installations are usually designed for high capacity per square foot of ground area, 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 to 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 Coal and Coke Coke ignites less readily than bituminous coal and more readily than anthracite, and bums rapidly with little draft. In order to control the air admitted to the fuel it is very, important that all openings or leaks into the ashpit be closed tightly. A coke fire responds rapidly to the opening of the dampers. This is an advantage in warming up the system, but it also 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 interval of attention as with other fuels, a deep fuel bed always should be maintained when burning coke. The grates should be shaken only 324 CHAPTER 13 1952 Guide slightly in mild weather, and should be shaken only until the first red particles drop from the grates in cold weather. The best size of coke for 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 1 in. screen. For . large fire-pots 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 COj 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 or Fuel in a Hand-Fired Fubnacb 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.1 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 COj and Oj. Some of the carbon dioxide of the bxidizing zone is reduced to carbon monoxide ih the upper layer of the fuel bed, noted as the reducing zone and indicated by the symbols COj 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 bum 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 to produce the same rate of binning and the same excess'air, depends on a 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 so important, because small pieces fuse together and form large lumps. Fortunately, a smaller size fuel gives more resistance to air flow through \ Fuels and Combustion 325 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 second ary air openings. For certain sizes of fuel, no secondary air openings are required, and for large; sizes, too much excess apr 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 unbumed 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 bed, and more frequent cleanings to keep its resistance down. Insufficient draft also restricts the control that can be accomplished by adjustment of the dampers. For draft requirements see Chapter 16. The quantity of excess air present has a marked effect on the draft required to produce a given rate of burning. If the excess is caused by holes in the fuel bed, or an extremely thin fuel bed, it is often possible to produce a higher rate of burning by increasing the thickness.of the bed. The thickness of the fuel bed should not, however, be increased top much, because the increased draft resistance will reduce the rate of primary air supply and the rate of burning. Draft Regulation for Coal and Coke Firing Because of the varying heating load demands present in most instal lations, it is necessary to vary the rate of fuel burning. The maintenance of the proper air supply for the various rates of burning is accomplished by regulation of the drafts. Methods of draft regulation used for solid fuel are shown in Fig. 2. The air enters through the ashpit draft door, firing 326 CHAPTER 13 1952 Guide l > door, and by leaks in the setting, whereas the gases leave only through the outlet. By throttling the gases with the damper in the outlet all the air entering by each of file 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 fiirough the other two intake openings, resulting in an increase of excess air. A considerable increase in the efficiency of hand:fired furnaces and boilers can be realized by regulating the air supply by means of the damper in the outlet instead of the, ashpit damper. Use of the ashpit damper is required, of course, for low rates of combustion. The cold air check damper , is to be used only when chimney draft is excessive. It is normally closed unless closing of the outlet damper and ashpit damper is unable to control the rate of combustion. Furnace Volume for Coal and Coke - The principal requirements for a hand-fired furnace are that it shall have enough grate area and correctly proportioned combustion space. The amount of grate area required is dependent upon the desired combus tion rate. The furnace volume is influenced by the kind of coal used. Bituminous coals, on account of their long-flaming characteristic, require more space in which to bum the gases of combustion completely than do the coals low in volatile matter. For burning high volatile coals, provision should be made for mixing the combustible gases thoroughly, so that combustion is complete before the gases come in contact with the relatively cool heating surfaces. An abrupt change in the direction of flow tends to mix the gases of combustion more thoroughly. Anthracite requires com paratively, little combustion space. ' CLASSIFICATION OF FUEL OILS - Fuel oils are mixtures of hydrocarbons derived from crude petroleum by refining processes designed to produce suitable proportions of naphtha, gasoline, kerosene, fuel oil, and lubricating oil. The processes leave a residue of coke, asphalt, or paraffin depending on the source of the crude oik In the past, refining processes have been directed toward producing the maxi mum amount of gasoline, because this product was in greatest demand. Fuels and Combustion 327 The relative proportions of gasoline and fuel oil produced, per unit volume 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-eracked 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. Analysis of Fuel Oils Crude oil in its natural state contains primarily paraffin hydrocarbons (chemical formula CnHin+i, naphthene hydrocarbons (formula CJff&), and aromatic hydrocarbons (formula CnHta-e) where n is a whole number. Fuel oils produced by pure distillation, that is the straight-run fuel oils contain essentially these same hydrocarbons. Those produced by crack ing processes may. contain generally all the hydrocarbon series from CnHia+I to CJiin-u, and especially do they contain appreciable percentages of the olefin hydrocarbons which are relatively less stable than file paraffin, napthene, and aromatic hydrocarbons. The paraffin hydrocarbons are hydrogen-saturated, are among the most stable, and have the highest hydrogen-carbon ratio of any of the hydrocarbon series. The straight-run fuel oils have the highest paraffin content, the highest hydrogen-carbon ratio and are the most stable of the fuel oils. The thermally-cracked fuel oils have the lowest paraffin content while the catalytically-cracked fuel oils are intermediate' in paraffin content and stability. The hydrogencarbon 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 some 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 use 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. 328 .CHAPTER 13 1952 Guide <1 fa CD a s s i fa o .a s 3 z i - 02 a. 'i s Bao s 'a *2_fa. &I- 02 J,. 1 * o3 00 a Max. 1 M in. sslh o Mi o j fa Z3 g ii ag 0S H ts. 3 10% 90% E nd Point Point Point 1 i s Max. Max. s tSo ' t--o ' Rtt> 32.1 (81) .. ce>* n 11 I-2 t J g la fa J 8 -S09 ' "S. " Sa-a a- lag 1& "f *h IS a I `!>> ."^S. . ou-'.a&au 3^| 5JI I'fS jls <0 3 " o CO - .g ia8 aoo*-g-' tgiSl--i a-Ss f3* %?s.215s >aaQi> If I il'-a st ostsg-Sj&ft.9l grj~g . al 8 8 a. * a 3 c a a=3 a s3^o, 9s*a gs ;33'S agmS,,S** a?o^.o~ s23-as|^go , 5 ga fa a*- _ 2 o"I-** aiZ 2* acs s glfsf . 1 Og o 3 S1a s 3 -fa oP3U fa o fa M ax.' ' Trace 0.15 CO o i t.'a a no or oo c* 00*1 oro o n A residual type o il for burner installa ' 130 tions equipped w ith preheating facilities or Legal A n o il fo r burner installations not 110 equipped w ith preheating facilities or Legal i Legal ing No. 1 A .P .I. g ra v ity 26 (m in.) fuosreIgnenberuarln pe rusrpnooster edoq umier e- A distillate o il intended for vaporising pot-type burners and other burners re q u irin g this graded A .P J . g ra vity 35 (m in.) -O A o a f3a bO. HQ <3 o --* C-i . A distillate tio heating oil for >d <D. A n o il fo r use in burners equipped w ith preheaters p e rm ittin g a high viscosity 150 or Legal . >Ib-* c io ;dzj "o**s-* e--a si *2 3O'*33 a#. a Or J*s3SJ3 3.s 1=3 . s as fi 38* 2a w wfc a=-2 5S5Bao o<" : a 2 s 'cs-5 ;|.S i 5 ig.S'S2 I B.3d d iSaH ' gs T a b l e 4. Flash Point F V; --j Fuels and Combustion 329 Table 5. Approximate Gravitt and Calorific Value of Standard' Grades of Fuel Oil Commercial Standabd No. Approximate Gravitt Range - AJ>J. Calorific Value Bttj Per Gallon i .2 4 5 6 35-45 26-40 12-25 10-23 8-17.5 138,800-132,900 144,300-135,800 153,000-145,000 154,600-146,200 156,000-149,700 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 unbumed 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 in 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. Some of these characteristics of a fuel oil are required to lie within certain limits for each of the grades of fuel oil listed in Commercial Standard CS12-48. Some fuel oils do not fall into any of the grade classifications of the Commercial Standard because failure to comply with all of the re quirements of one grade does not automatically place the fuel oil in the next 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 cent carbon, 12.0 to 13.5 percent hydrogen, one to three percent oxygen and nitrogen, and 0.5 percent or less of sulfur. The heavier grades of fuel oil, Nos. 4, 5 and 6, may contain as much as 88 percent carbon, as low as 11 percent hydrogen, and considerably more sulfur than is permissible in the domestic grades. Due to variation in the constituents of different fuel oils and the differ ent refining methods used, the API gravities and calorific values of the different grades of fuel oil cover a range in each grade with some overlapping between domestic grades and between commercial and industrial grades. The relation between the API gravity of fuel oils and their calorific 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 33 0 C/ H' APTER 13 1952 Guide - 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 new experimental evidence. Much, still remains unknown about the process of decomposition and combustion of hydrocarbons. . t.. . Only three theories will be discussed here: (1) the carbonic combustion theory, (2) the aldehydeous combustion theory, and (3) the chain reaction theory. The carbonic combustion theory postulates that thermal destruction of hydrocarbon molecules is likely to occur if (1) the oil is suddenly exposed Pig. 3. Illustration of.Blue and Yellow Flame Combustion 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 be thermally decomposed into hydrocarbons of lower molecular weight along with some free carbon atoms released under the conditions just described. The free carbon atoms may produce smoky combustion while those carbon atoms that are oxidized to carbon, dioxide will produce a yellow luminous flame. ' 't The aldehydeous combustion theory is based on the evidence that alde hydes, alcohols, and possibly peroxides are formed as intermediate products when hydrocarbons are decomposed and oxidized to the final products of combustion. The formation of formaldehyde is certain since. it can be identified in the flue gases from blue flame oil burners when insufficient combustion air is provided. Alcohols have been identified by certain in vestigators during the oxidation of methane and ethane. Aldehydeous combustion is illustrated by the blue flame oil burner and the conditions conducive to this type of hydrocarbon decomposition consist of (1) allowing the oil time and opportunity to evaporate completely prior to combustion, (2) mixing the air and oil vapor thoroughly before combustion, and (3) pre heating the air or the mixture. Blue and yellow flame combustion can be demonstrated by the apparatus 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 \ Fuels and Combustion 331 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 aide-hydeous combustion theory since most investigators who have studied the former have observed that the formation of aldehydes is one of the steps in the combustion process. It has been well established that fuel oils 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,6 Pease, and others have advanced the theory that that the reactions between hydrocarbons and oxygen are probably chain reactions. This theory postulates that a great many different reactions take place simultaneously or progressively between molecules, atoms, .and radicals 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. Time, temperature, pressure, light v and certain catalytic agents all may affect the speed and nature of these processes. The kind of intermediate products formed before combustion is complete 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 substances, have all been identified as intermediate products in certain reactions. The chain reaction theory, in reality embraces and elaborates on the aldehydeous combustion theory. Oil Burning Indexes A number of indexes have been used, or proposed, as an indication of the burning qualities of fuel oils based on one or more physical measure ments made on the oil. These may be summarized as follows: . A. Indexes based on a single physical test: (1) API gravity7, (2) Aniline point8, (3) Institute of Petroleum smoke test, (4) Carbon-Hydrogen ratio based on flue gas analysis or ultimate analysis, and (5) Percent aromatics determined by sulfuric acid absorption tests*. B. Indexes based on two or more physical tests: (1) Diesel index* based on API gravity and aniline point, (2) Institute of Petroleum cetane number 10 based on the API gravity and 50 percent distillation point, (3) Universal Oil Products characteri zation factor11 based on specific gravity and average boiling point, (4) Burning index11 based on API gravity and 50 percent distillation point, and (5) Estimated Carbon- Hydrogen ratio1* based on API gravity aniline point, and boiling point. . Various investigators have shown correlation between one or more of these indexes and the performance of fuel oils in oil burners. Experiments conducted with the Oil Heal Institute Reference Test Unit18 indicated good correlation between the smoking tendency of fuel oils and API gravity, burning index, Diesel index, and hydrogen-carbon ratio for a limited num ber of oils in laboratory apparatus simulating a pressure-atomizing burner. These results are shown graphically in Fig. 4. Smoking tendency is given here in terms of smoke spot reflectance, the light reflectance of a smoke- 332 CHAPTER 13 1952 Guide soiled `filter paper. A high reflectance, relative to a clean filter paper,' indicates low smoking tendency. 00%/U is the observed CO% divided by the ultimate or maximum theoretical CO% expressed as a percentage: Reid and Hersberger12 have related burning qualities arid burning index for various oils in a wall-flame burner. Cauley and Delgass18 cite test results on combustion indexes obtained with vaporizing burners. The present experimental data are probably too meager as yet to correlate adequately any one of these indexes with burning qualities of oil fuei for all types of burners. Few attempts have been made to suggest limits for any of these fuel oil`indexes for particular applications, even though correlations be tween them and burning qualities have been observed. In other words, o Smoke Spot Reflectonce for 80% of Uitimote CO* A Per Cent of Uitimote CO* for 80% Relotive Reflectance 25 3 80 30 35 40 API GRAVITY -Arff < r CO* . 45 (kLj 02) - -70 60 50 mol e a1 0.12 0.13 0.14 0.15 0.16 HYDROGEN-CARBON RATIO O \ a do* 5 1/ V ' a\ b oke -o. -o-- 0 20 40 60 DIESEL INDEX o CO u e< 80.lOO-'-Po 3u. 20t HO** . - Oa. Q 40- -tn cc Hosci o . - 60"`Stn '< A Sm ake d zo 40 60 80 BURNING tNOEX 100-L 100 ' Fig. 4. Correlation op Burning Qualities of Fuel Oils with Four ' Combustion Indexes . hone 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 therrdal 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 Standard CS12-48 has a maxi- \ Fuels and Combustion 333 .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 tion of the fuel, and high combustion chamber temperatures (preferably red hot) promote smokeless combustion with a minimum of excess air. Natural draft burners depend on the motivating force of a chimney to induce enough air into the burner for complete combustion. Forced draft burners are supplied with combustion air by means of a blower or fan; the chimney merely conducts the flue gases outdoors and prevents leakage x 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 14 and 16 respectively. . FUEL GASES Fuel gases employed for various heating and air conditioning processes throughout the United States fall into three broad classifications: natural, manufactured, and liquefied petroleum. Natural gas is a mixture of several combustible gases and, usually, a small percentage of inert gases obtained from geologic formations. Natural gas is produced in significant amounts in 20 states. Texas is by far the largest producer, followed by Louisiana, Oklahoma, California, Kansas, and West Virginia. Manufactured gas is made by the distillation or cracking of oil or coal, by the steam carbon 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 hquefied 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 hquefied 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 334 CHAPTER 13 1952 Guide 1129 1021 2558 2358 2504 2316 3210 2961 3184 2935 550 516 Spe cific G rav ity* N et' . HKm% gD a g o u)NOOh' o -i -< e* i--i NOuHCOot--o(Nt-'^-.OaiOa-N(JCCOC5MiOH^NOt-OQ aeMeCMo IQ Tf rH CM a-O0 CO i-H'^OOt'-COcM'^'^OOcOMt'--COcoCcD f-JOOO 700 627 NCM 1 CM CM ? . 0.46 0.52 0.79 a `o w o o X o o ,, o o 7 "oo - cS C$<N: ' 00 tn -w.*s d d^ .aoaS *o 00 - cm 3 3 .OOMCJ"COD N CO CJ O O ONNNW5 GOOO a CM CM S .................... oo cmoocm . tHCCOJCONCO "` "*-ooti--H- *` III CO CM : .................... .... H 05 - .IT..*........................ . IQ O CO iH CM CO CD lO W 05 t-- CO CM CO CM CO HcoWcoc'#d- a"0* CO CM ID OJ a CM 00 ' CO O'tfOHCiOo^io-^iIO-Hi-i^H^HCScIoCcMoOcO* N-< aCO CMp-aeMoot'-c WHNO*-iO-NcmNcOm cOm ciOm h*-O--* iTt<Tt<00O5o^00tf5 r-H CM ' l 55 NCM T--D1 OUi-5H CO CM I CM CO CD C505C0i-f O t-HCMCM*tit--05 i-i eMi-teocM^*-ncoco CM . CM CM CM O ,- CO CM CD CCMM* f LIS w ith b B lu e , N a tu ra ural T his table abstracted from Gaseous F u e l*, Am erican. Oae A. ssocia.tion, and from A .Q .A . Laboratories Data. 0A t 60F and 30 in . meroury, absolute pressure. . T a b l e 6. T y p ic a l G as A n alyses Constituents o f Oas--Percent by Volume C .H , 'oo' 'm' *t*i &to *to s&0. 7Ch3O ^>OL7* 8h33 LOa . s a3 a * 22 * wwww e8 aS 3 cG 7__ *L03a *L0oa 'LS0a 'L5a) 3aebs >aoaoseo ao HOOOO uo o2S *'* ' to af-s ` ^O o i? t* . -S |o "e.fol.--g->.-3a a &. J.S 'g '3 ata 913 ^aoo La s 2* : !k o :s|^g| *2 - os*** o mWWF: o 3> o O o hH *cL5. *s 3 43cS^ a 55 p H --dhbo eCel c0o5) $fl 0a 0f.l 3*2 oa, ao * ***2 *a* ^cmLcqpqm ^CMCO^acO cfi cj bo bo <s5 aj && S> 2 73*0 *tg-3ra b-.s>3-1 . +-W.**oC8*G3O'j S g 3^ "3 3-0 |^||-gl tfpjooo&SSooii l**OOOOiHNW^>0N CS O D O s o -O s .8 a&<>D 00 05 . \ Fuels and Combustion 335 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. 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 transcontinental transmission lines, into areas having existing manufac tured gas facilities. In such instances some gas companies supply a 600 to 800 Btu mixture (See Table 6). In some territories these mixtures are distributed as an intermediate step in changing over from manufactured gas to natural gas. Although the burden of adjusting installed heating and air conditioning equipment and supplying, new orifices and burnerequipment is generally assumed by the gas companies when the gas ischanged, it is advisable to consult the local gas company to insure that equipment is provided with proper orifices and burners when installed. Most states enforce legislation through their public service commissions to require delivery of a gas of specified average or minimum heating value within their respective limits. Any given heating value within reason fortunately may be maintained and yet permit considerable latitude in the composition of the gas distributed. Hence the 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 336 CHAPTER 13 1952 Guide " 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 it 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 will 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. It is important to note that gas furnaces and boilers, as well as most other classes of heating equipment, are designed to create their own draft. The air-to-gas ratio in a Bunsen burner head has a decided effect on the rate of flame propagation. The gas-air mixture must flow from the burner ports faster than the flame bums, otherwise flashback will occur. The flashback condition normally results either from an excess amount of primary air or insufficient gas or both. Conversely, the velocity of the issuing mixture must not be so high that the flame will be blown from the ports, a condition known as lifting. Fortunately, contemporary types of such burners have a rather wide range of flexibility, in capacity and adjust 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 asssmed by the local utility providing the supply of gas. It should be recognized that a change in fuel gas will change the operating C02 value. For example, an appliance operating on carburetted water gas at 20 percent excess air will have 14.2 percent COs 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 COi 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 Fuels and Combustion 337 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 14. Care must be exercised to insure adequate air supply for combustion equipment installed in buildings or other structures. Where the equip ment is closely confined, as in closets or small furnace or boiler rooms, the air supply must also provide for ventilation. Current recommended prac tices are: '. 1. Where the equipment is not closely confined (typical cellar installation.or equiv alent) provide not less than 1 sq in. of free access tooutside air for each 1000 Btu per hr heat release of fuel consumed. Infiltration into conventional frame or brick construction, unless unusually tight with storm windows and tight doors, provides adequate air. 2. Where the equipment is closely confined, provide two openings to outside air or from spaces freely communicating to the outside. One opening should be near the . top of the equipment enclosure and the other near the bottom. Each opening should have not less than ) sq in. of free area for each 1000 Btu per hr heat release of fuel burned, and.should communicate to air source or outside by suitable ducts. Where the enclosure is in a building of otherwise, conventional construction, and the air source will be the normal infiltration into building, each opening shall have not less than 1 sq in. of free area for each 1000 Bu per hi- heat release. - 3. Clearances from equipment to closely confining enclosures should conform to local codes and to standards listed by recognized agencies such as AGA Testing Lab oratories! and Underwriters' Laboratories.a See Fig. 5 for details concerning installa tion of gas burning equipment.1' 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, the combustible constituents of solid, liquid, and even gaseous fuels can not be completely burned. Incomplete or partial combustion of all fuels produces toxic gases, such as carbon monoxide, with smaller quantities of aldehydes, ketones,, and other hydroxylated hydrocarbon compounds. t o t a l lo s s in f l u e g a s in p e r c e n t : 338 C0APTER 13 , 1952 Guide 1' j " -This fact indicates that, while combustion processes involving common types of fuel may be regulated by experienced operators to produce the | most efficient results, normal combustion processes can be so imbalanced as J to create hazards unless both design and operation are planned with'a knowl edge of the fundamental principles of combustion. - : ' ,. ! i s' . '! j Combustion may be defined as the chemical combination of a substance with oxygen resulting in the evolution of heat, and usually some light. The rate of combustion depends upon the rate of reaction of the'substance with oxygen, upon the rate at which oxygen is supplied, and upon the temperature 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 Fuels and Combustion 339 1 .j t i Fjg. 5. Illustration. Showing Air Openings Necessary to Supply Air for Combustion When Appliance is Installed in Confined Space A. Ventilating air outlet register for furnace room, 1 aq in. freearea for each 1000 Btu per hrfurnace input located above relief opening of draft hood. Register must not be blocked by drapes or other furnishings. B, Both regfcters must either face same large ventilated interior space or extend to such space by means of ducts. Vertical distance C/L to C/L of registers should be notless than 3} ft'. '- C. Suggest room access door be not less than 6 ft high by a width sufficient to provide for installation or removal of furnace. Atl east 2 ft horizontal clearance should be provided in front of furnace when close t door is open, or 18 in. when door is closed. . ?" pomhustion and ventilation air inlet register for furnace room, 1 sq in. free area for each 1000 Btu per hr furnace inputg located at or below combustion air inlet to furnace.- -Register must not be blocked by drapes or other furnishings. .- - circulated byf urnace must be handled by duets which are sealed to furnace casing and are entirely separate from means provided for supplying oombustion and ventilation air. F. Spacing between draft hood and wall at least 6 in. (unless approved for closer spacing). If flue product t he directed toward wall, 12 in. spacing recommended. xx* S pa?^ * 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 perform ance. In installations where the flue terminal is below nearby walls or roof peaks, an effective vent cowl should be used. -' the combustion process. For a continuous reaction, as in heating processes, it is necessary to establish an effective balance between rates of removing heat and of supplying fuel and air or oxygen to keep the reaction.going. In establishing such a balance, consideration must be given to the removal or venting of products of combustion, so that the entire process is one of flow wherein draft conditions in the combustion space play an important part. . Complete combustion is obtained when all combustible elements in a fuel are oxidized, by all of the oxygen with which they will combine. All oxygen or air supplied is generally not utilized, and this excess portion is TO TAL LOSS in f l u e g a s in per c e n t Anthracite Fuel Oil Fig. 6. Flue Gas Losses with Various Fuels* Flue Gas Temperature Shown. Loss is Based on 65 F Room Temperature. 340 CHAFER 13 1952 Guide 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 for complete combustion of all elements of a fuel is supplied and utilized. The 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 C02 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 %co. % EXCESS AS IN FLUE GASES % EXCESS AIR . %C0, IN FLUE GASES . * --00" 500 ~ -400-- - r90 Hr40 - It) J- - -100 / -50 10- . . a ' %FLU LOSS BUTANE ANO PROPANE -a % FLUE LOSS 90 -c o -a Adapted from American Gas Association Laboratories Fine Loss Charts* - Pig. 7. Alignment Chart for Calculation of Plue XiOSSes fob . Butane, Propane, Coke Oven, and Natural Gases . of heating equipment must be sufficiently flexible in performance to pro 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 it advisable, from a practical standpoint, to insure complete combustion but not perfect combustion in the sense expressed above. To attempt to do so would undoubtedly result eventually in unsatisfactory performance especially from a safety standpoint. Consequently, common types of 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 economically. Reference to flue loss charts such as Figs. 6 and 7 for gas burning equip ment and to the air requirements discussion in Chapter 14 shows that Fuels and Combustion 341 reasonable quantities of excess air can be used without appreciable reduc tions in operating efficiencies. Oxygen combines with the combustible elements and compounds of any fuel in accordance with fixed laws. The reactions and resultant products of perfect combustion of common fuel constituents are set forth in Table 7. All of the oxygen required for combustion is normally obtained from the surrounding air, which is a mechanical mixture of nitrogen and oxygen with small amounts of carbon dioxide, water vapor and inert; gases. For prac tical combustion calculations, air is considered to consist of 20.9 percent oxygen and 79.1 percent nitrogen by volume, and 23.15 percent oxygen and 76.85 percent nitrogen by weight. The nitrogen, being inert, passes through , the reaction without change. Table 7 gives the air quantities corresponding to the oxygen required for perfect combustion. Air supplied to the combustion reaction is in most instances introduced in two ways. Primary air is introduced through or with the fuel, and secondary air is supplied to the flames issuing from the fuel. Incomplete combustion is obtained when any of the combustible elements are not completely oxidized in the combustion reaction. This condition not only represents inefficient use of the fuel but also presents a hazard because carbon monoxide is usually one of the products of incomplete combustion. For example, a hydrocarbon may not oxidize completely to 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 tbe 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 by products of combustion not properly vented), or insufficient mixing of the air and fuel, are the primary causes of incomplete combustion. Heat of Combustion As previously stated, the process of combustion results in the evolution of heat. The heat generated by .the complete combustion of a unit of fuel is constant for a given combination of combustible elements and com pounds, and is known as the heat of combustion, calorific value, , or heating value of the fuel. The heat of combustion of the several substances found in the more common fuels is given in Table 7. .. The calorific value of a fuel may be determined either by direct 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 js determined in a calorimeter, the water vapor is condensed and the latent heat of vaporization is included in the heating value of the fuel. The heat ing value so determined is termed the gross or higher heating value, and this is what is ordinarily meant when the beating value of a fuel is specified, hn 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, C0%, the hydrogen unites with oxygen to form water vapor, Hfi, and the nitrogen, being inert, passes through the re action without change. When combustion is incomplete, some of the CfL,n may unite with oxygen to form carbon monoxide, CO, and some of tiie 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 T a b l e 7. G e n e r a l D a t a o r C o m b u s t ib l e 'E le m e n t s a n d C o m po unds' 342 OSOM is, no ISQ -sggv leg CQ CHAPTER 13 1952 Guide l. i l l s f-l ' 09 .M wH 09 00 t- CQ i--< 09 . -co o o 09 09 co co 9 O 09 8 CO aO lO C5 t-- - 09 CO ' ^ 05 o ^ . b- 05 co co co' co co CO co 00 rP I e> p co co*. co I I f. I CO co 09 to 1-1 05 1~1 05 09 o ^ co t". co 8 C9 C9 09 S g `8 S3 8 . eo>' r* 05 a5 ^ ^ t-05 05 CO CO CO ' i- 00 o r . o1-1 coCO Oeo CvoO 5 2 S3co *0 ^ cjg 09 09 09 C9 09 09 09 II g8 O . 09 o CQ O d +++ C9 09 CO II S3 09 CD- 00 '00 i .co. 2, i i i i CD CD 00 05 CD 05 to 05 05 00 09 05 O 05 o q q d d O O o. +o &s co 09 Sd *Til 09 .+. + +d + 'O o oo 09 d o o oTjl 09 a B EU cm ? *C39 O55 o. CO Q O I <5 8 8+ + +H d to d 6 N CO D . +" .+ t q ++ o EC 5 60 ttj oO O 09 q c CM CM o I 9 8 i e 3 till % % *5 ~ ^ ^ 3 o o o aj q o G O _r o! T3 `S 60 aaj o. oLi PH O a o o S3 O0-O0 m A to t* a 3 2 -2 <S c5 3 O O. aua >t c3 S SA SA *o O. H 2 O g < S H fl K ft a m a . 03 2 .9* >g 3 S-2 l og S 5m a JSS .o ^ 5|a .9 1 8 8 9 .2 g 2 >og Fuels and Combustion 343 combustion efficiency is obtained. Incomplete combustion may result from any or all of the followingthree conditions: (1) inadequate air supply, (2) insufficient mixing of air and gases, and (3) a temperature too low to pro duce 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: .. . Pounds air required per pound fuel = 34.56 (2) For Gaseous Fuels: . Cubic feet air required per cubic foot gas = 2.39 (CO + Ht) + 9.53 CH, + 16.68 CtH, + 23.82 C,H, + 30.97 CJL0 + 11.91- CH, + 14.29 C,Ht + . 7.15 HtS -- 4.78 Oj + 30.47.Dluminants (3) Gaseous fuels may contain a wide variety of components classified as iUuminahts, which are not separated by the usual methods of gas analysis. The principal ones in addition to ethylene and acetylene which are included in Equation 3, with the air required per cubic foot of gas are: propylene, 21.44; butylene, 28.58; pentene, 35.73; benzene, 35.73; toluene, 42.88; and xylene,. 50.02. Since toluene and xylene are normally scrubbed from the gas before distribution; they may be disregarded in computing air required for a fuel gas. An approximate value of 30.47. (as shown in Equation 3) may, therefore, be employed. If ethylene and acetylene are included as iUuminants, 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 is expressed as follows: Pounds air required per. pound fuel = 2.47 CO 4- 34.34 Hi + 17.27 Cf7 + 16.12 C,H, + 15.70 CiHs + 15.49 CJ7io + 13.30 CiH, + 14.81 CiH, + 6.10 HS - 4.32 0, (4) Where 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 on 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. Su.'- 344 CHAPTER 13 1952 Guide Table 8. Approximate Air Requirements for Theoretically Perfect -' ` Combustion of Fuels* " Ttpe OF Fuel Air Requires fob Perfect Combustion Lin per Lb Fuel . Cu Ft per Unit^ Fuel AppboxiPreci- Per Cent Exceptions Solid Btu per lb X 0.00073 Btu per lb X 0.0097 3 Fuels containing : more than-30% . . water ` Liquid Btu per lb X 0.00071 Btu per lb X 0.0094 . 3 Results low for gasoline and kerosene Gas Btu per lb X 0.00067 Btu per cu ft X .0.0089 . 5, Gases of. 300 Btu per. cu ft or `' less _ .. .: a Values in table taken from page 276 of Gaseous Fuels, 1648, published by American Gas Association. ' & 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. 2, 105.5; No. 5, 112; No. 6, 114.2. 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. COMBUSTION EFFICIENCY FROM THE FLUE GAS ANALYSIS .. . - . - Excess Air A commonly employed index of efficiency of combustion is the relation existing between the amount of air theoretically required for perfect com bustion and the amount of air actually supplied. Since the difference between air supplied for combustion and theoretical air required is charac terized as excess air, its percentage may be calculated by use of the follow ing equation, : -( -)>Percent excess air Air supplied -- Theoretical air X 100 Theoretical air (5) ` The amount of dry air supplied per pound of fuel burned may be obtained from Equation 6 which has reasonable precision for most solid and liquid fuels. Values for C02, CO and N, are percentages by volume from the flue gas analysis, and C is the weight of: carbon burned per pound of fuel, cor rected: for carbon in the ash. 3.04Nt %; _ Pounds.dry air supplied per pound of fuel X (CO, + CO) x (6) Because excess air calculations are almost invariably made from Orsat analysis results, and theoretical air requirements are not always known, another convenient method of expressing the relation of Equation 5 is as follows:- ' - _ . 100(0, -CO/2) Percent excess air = ^ x 0 264 _ (0j _ c0/2) : (7> f. K' if H W U | V 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 ; . ' Percent excess air = . X 100 -- . . CO, . A (8) Fuels and Combustion 345 Table 9. Approximate Maximum Theoretical CO, Values, and 1 CO, Values for Various Fuels with Different Percentages of' ` Excess Air ' i,! . . Type of Fuel Coke Anthracite Bituminous Coal No. 1 and 2 Fuel Oil ' . - Maximum Theoretical or Ultimate Percent COs Percent COs at Given Excess Air Values : 20% ' . 40% 60% . ; 21.0 20.2 18.2 . 15.0 17.5: . 16.8 15.1 . 12.3 15.0 ' 14.4 12.9 10.5 :. 13.0 ' f 12.6 11.3 9.1, No. 6 Fuel Oil Natural Gas Carburetted Water Gas Coke Oven Gas : ,; 16.5 12.1 17.2 11.2 13.6 9.9 .14.2 9.2 11.6 8.4; . 12:1 7.8 . '10.1 7.3 10.6 6.8 Mixed Gas (Natural and . retted Water Gas) Propane Gas (Commercial) Butane Gas (Commercial) Carbu- 15.3 13.9 . 14.1 ' 12.5 11.4 il.6" . 10.5 9.6 9:8 ' . 9.1 8.4 - 8.5 where U = ultimate carbon, dioxide, percent of flue gases resulting from perfect cdm- . bustion. 1 : CO, " carbon dioxide content of flue gases, percent. P = dry products from perfect combustion, cubic feet per cubic: foot of gas burned. ' : - . -4 -- air theoretically required for complete combustion,- -'cubic-feet-per-cubic ' foot of gas burned. 1 As the ratio of P/A is approximately 0.9 for most city gases, a value of 90 may be substituted: for 100 in Equation s for rough calculation. Carbon-hydrogen ratios of different fuels vary considerably, 'hence the maximum or ultimate CO, attainable also varies. Where they are un known, theoretical maximum CO, values may be calculated from a flue gas analysis by use of Equation 9. ;. , ' , Maximum theoretical % CO, = % COs i Aue gas sample.X 1Q0V . ... ' / O, in same sampleX "V 0.21 ) . .. Approximate maximum CO, values for perfect combustion' of . several common types of fuel sire shown in Table 9 , together with values of CO! that will be attained with different amounts of excess air. Dearable values attained Pracrice depend upon the fuel, the method of Airing, and other considerations. In general, fuels burned in suspension, such as gas, Pn, 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 baac requirements must be met: (1) adequate heat absorbing surface of proper shape and construction is necessary in the appliance, (2) heat transler 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 are covered, with soot, ash, or scale,' flue losses will generally be excessive 346 CHAPTER 13 1952 Guide - due to the large amount of sensible heat escaping to the chimney. Too much excess air dilutes flue gases excessively add increases sensible flue gas loss. On the other hand, a deficiency of excess air will in all probability cause incomplete combustion, and some of the combustible gases will pass from the appliance without being completely burned. Highest combus 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 wall enable the observer to compute the amount of flue gases produced, the excess air, the actual quantity of air supplied for com bustion, and the flue losses. While the analysis of flue gases has been well described in several governmental and other scientific publications, the subject is of such importance that it warrants brief repetition here. Carbon dioxide and oxygen content are of principal interest in determining flue losses. Either or both of these values may be employed in such 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 49 for details regarding the 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. ' 11C0i + 80, + 7 (CO + A,) Pounds dry flue gas per pound fuel = 3 (CO, + CO) (10) Values for (70, 02, CO, and AT, are percentages by volume from the flue gas analysis, and C is the weight of carbon burned per pound of fuel, cor rected for carbon in the ash. Total dry gas volumes of flue gases resulting from the combustion of one cubic foot of gaseous fuels for various percentages of (702 may be deter 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. (ID \ Fuels and Combustion 347 After obtaining the quantity of flue gases from Equations 10'or 11, the excess air quantity may be determined by' subtracting the quantity of: dry 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,, 3.1percent O,, and 86.9 percent. A, by volume. The analysis of the fuel is 90 percent CHt, 5 percent A,, and 5 percent CJSt by volume. Find U the maximum theoretical percent CO, and the percent excess.air. Solution: From Equation 9: (10.0)(100) 11.8% CO, \02lJ From Equation 8, (11.8 - 10.0) X 90 Percent Excess Air = 10 16.2 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) (CJ?4) + (16.68)(CtH,) = 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,)(9.528 -- 2.0) 6.78 From ethane = (0.05 CtH,) (16.675 - 3.0) = 0.68 Nitrogen in fuel = - 0.05 Nitrogen in excess air = 0.791 X .162 X 9.41 = 1.20 . Total Nitrogen 8.71 cu ft Oxygen, O,: Oxygen in excess air = 0.209 X .162 X 9.41 = 0.32 cu ft Carbon dioxide, COi: From methane = -(0.9 CHO(l.O) =0.90 From ethane = (0.05 CJf,)(4.0/2.0) = 0.10 : Total Carbon Dioxide 1.00 cu ft Water vapor, H/) (does not appear in Orsat analysis): (0.9 CH,) (2.0) =1.8 (0.05 C,ff,)(6.0/2.0) = .15 Total water vapor = 1.95 cu ft Total volume of dry gas per cubic foot of gas: ' ' ' 8.71 + 0.32 + 1.00 = 10.03 cu ft Total volume of wet gases per cubic foot of gas (neglecting water vapor in combus tion air): ' 10.03 + 1.95 = 11.98 cu ft The cubic feet of dry flue gas per cubic foot of fuel gas may also be computed from Equation II as follows: ' (1.00) (100) 10.0 10.0 cu ft HEAT BALANCE The usual practice in analyzing the performance of heating appliances is to make an accounting, insofar as possible, of the disposition of all heat units available in the quantity of fuel burned. This accounting is called 348 CHAPTER 13 .1952 Guide -a heat balance. Various components of this balance are generally expressed in terms of Btu per pound of fuel burned, or as a percentage of its calorific value. Components of special interest are listed as items 1 to 7 inclusive. 1. Useful heat transferred to heating medium, usually computed by . determining the rate of flow of the heating'fluid through the heating device, and the change in enthalpy of the fluid (heat added) between the inlet and outlet. 2. Heat loss in the dry chimney gases'. - A, = ujjCp ((, - f.) : . (12) 3. Heat loss in water vapor formed by the combustion of Hydrogen. 9Ht A. = -- (1091.8 + 0.455,(1, - /.) (13) 4. Heat loss in water vapor in the air supplied for combustion. ht = 0.455 M (t, -- 1.) 5. Heat loss from incomplete combustion. . ,. :. . ; . , . h, = 10143 Cy(Vc(o-sc-+0-co)/ 6. Heat loss from unburned carbon in the ash or ret fuse. (14) (15) . As = 14600* I Vioo ) (16) 7. Radiation and all other unaccounted for losses. Radiation and convection losses from a heating appliance are not usually deter mined by direct measurement. For tHis reason they, together with any other losses not measured, are determined by subtracting the total of items 1 to 6 from the heat of combustion of the fuel. If the heating appliance is located within the heated space, however, radiation and convection losses may be considered as useful heat rather than lost heat.' They may, therefore, be omitted from calculations of heat 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 are: Ai = heat loss in the dry chimney gases, Btu per pound of fuel. A, = heat loss in water vapor from combustion of hydrogen, Btu per pound of fuel. .. A, = heat loss in water vapor in combustion air, Btu per pound of fuel. A, = heat loss from incomplete combustion of carbon, Btu per pound, of fuel. A, = heat loss from unburned carbon in the ash, Btu per pound of fuel. to, = weight of dry flue gas per pound of fuel (from Equation 10), pounds. , . cp = mean specific-heat of flue gases at constant pressure (cp ranges from 0.242 to 0.254 for flue gas temperatures from 300 F to 1000 F)*, Btu per pound. fg = temperature of flue gases at exit of heating device, Fahrenheit. 1 ' f. = temperature of combustion air, Fahrenheit. 1' Hi = 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 of \ . . . dry air. . , * A' value of 14600 applies in calculating ash pit loss; in calculating heat of formation of carbon compounds use-14093 Btu per lb. . ', Fuels and Combustion 349 10. -- weight of combustion air per pound of fuel used, pounds, from Equations . 2,4,5,6,7 and 8. , CO, COi = percentages of CO, COt in flue gases by volume. C = weight of carbon burned per pound of fuel corrected for carbon in ash, ' pounds. WC* - W.C. 100 W (17) where Cu = percentage of carbon in the fuel by weight from the ultimate analysis. IF. = weight of ash and refuse, pounds. . (7. = 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. 6*, if COt 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. : . ,. :: . Utilization of gaseous fuels, for numerous reasons, is generally a more sim ple process than is the case with either solid or liquid fuels.: 1 Accordingly, the determination of a practical heat balance is also a more simple procedure in that items 5 and 6 do not generally apply to gas installations. A series of typical alignment charts has been combined in Fig: 7 for use in determin ing flue 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 loss is indicated where the straight edge interesects the flue loss column. The operating efficiency of a gas appliance can then be'computed with sufficient precision by application of Equation 18. Percent Combustion Efficiency = . /Gross Btu of fuel \ _ /total flue losses per\' \gas per cubic foot/ ycubic foot fuel gas)/ ^ ^ Gross Btu of fuel gas per cubic foot .^g Reference to Table 9 will show that ultimate COt percentage values of fuel gases vary. While personal errors involved in COt, 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 by American Gas Association) and particularly to tables covering various properties of different commercial gases included in these publications. CONDENSATION AND CORROSION Sulfur dioxide or sulfur trioxide, formed by the combustion of sulfur in 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. 350 CHAPTER 13 1952 Guide Table 10. Average Flee Gas Dew-Point for Various Feels8 ` Type of Fuel ` Average Dew-Point Temperature, F Oil - ........... ................................ Butane-Air Gas Mixture (535 Btu/cu ft...........................,. 68 84 93 111 127 137 119 124 121 Therefore, unless heating equipment is designed for operation at flue gas temperatures below the dewpoint, which is seldom the case, it is always ad visable to maintain temperatures above this value in all parts of the ap pliance. Excessive spot temperatures in the combustion chamber or else where, on the other hand,, are also destructive in that they may result in 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 normal 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 dicated not only throughout the appliance, but in its connecting vent, flue, or chimney, as well. Otherwise, excessive condensation and corrosion problems, with resultant customer dissatisfaction, will in all probability be the result.. Average 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. SOOT The deposit of Soot on the flue surfaces of a boiler or heater acts as an insulating layer over the surface, and reduces the heat transmission to the water or air. The Bureau of Mines Report of Investigations No. 3272** shows that the loss of seasonal efficiency is not so great as has been 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 de crease in efficiency of an oil fired boiler, due to soot deposits, is relativelysmall, the attendant increase in stack temperature may be considerable. The soot accumulation clogs the flues, reduces the draft, and may pre vent proper combustion. Soot can probably be most effectively removed , by a jet of compressed air, by means of a brush, or a vacuum cleaner.- However, it has been found that copper chloride, lead chloride, tin chloride, zinc chloride, common salt and some other salts are partially effective in 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 49. . REFERENCES 1 Five Hundred Tests of Various Coals in Househeating Boilers (U. S. Bureau of Mines Bulletin No. 276). . 1 Combustion Efficiencies as Related to Performance of Domestic Heating Plants, Fuels and Combustion 351 | 'by A. P. Kratz, S. Konzo and D. W. Thompson ( University of-Illinois, Engineering Experiment Station Circular No. 44). ; 8 Quality of Anthracite as Prepared at Breakers, 1935 (U. S.Bureau of Mines Re port of Investigation, R. I. 3283). . 4 Hand Firing Soft Coal Under Power Plant Boilers (U. S. Bureau of Mines Tech nical Paper No. 80). . ............ ,. ' 6 Combustion Blames and Explosions of Gases. Lewis and von Elbe: (Cambridge University Press, 1938). :. 4 Oil Burning, by H. A. Romp (Martinus Nijhoff, 1937). 7 ASTM Test Designation D287-39. 8 ASTM Test Designation D611-43T. ` 8 Tomorrow's Fuel Oil, by W. A. Sullivan and E. B. Glendenning (Fueloil and Oil Heal, Vol. 4, No. 1. 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). 11 Burning Index for Distillates, by J. C. Reid and A. B. Hersberger. Fueloil and Oil Heal, Vol. 5, No. 9, Jan. 1947, p. 90). 18 Carbon Hydrogen Ratio of Catalytically Cracked Distillate Fuel Oils, byS. PCauley and E. B. Delgass (The Oil and Gas Journal, Vol. 45, No. 12 July 27, 1946, p. 166). 14 Rating of Fuel Oils by a Test Unit, by D. W. Locklin and G. V. Parmelee^ASHVE Journal Section, Heating, Piping and Air Conditioning, Dec. 1950, 18 Gaseous Fuels (American Gas Association, 1948, pp. 56-59). 18 Gas Analysis and Testing of Gaseous Materials by V. J. Altieri (American Gas Association, First Ed. 1945). . 18 Tentative Methods of Test for Specific Gravity of Gaseous Fuels (American Society for Testing Materials, ASTM Designation: 1070-49). . 18 Standard Method of Test for Calorific Value of Gaseous Fuels by the Water , Flow Calorimeter (American Society for Testing Materials, ASTM Designation: 900-48). . -" 18 American Standard for Installation of Gas Piping and Gas Appliances in Build ings. ASA Z 21.30 1950 (American Gas Association). 80 NBFU Standard for the Installation of Oil Burning Equipments--NBFU pam phlet no. 31 (National Board of Fire Underwriters). - 81 Domestic Gas Range Research (American Gas Association Laboratories Bulletin 7,P- 64). '88 Condensation of Moisture in Flues, by William R. Morgan (University of Hlinois, Engineering Experiment Station Circular No. 22). , 88 Effect of Soot on Heat Transmission in Boilers (U. S. Bureau of Mines Report of Investigation No. 3272). ' 84 Effect of Soot on the Rating of an Oil-Fired Heating Boiler (National Bureau of Standards Report BMS 54). , 88 Removal of Soot from Furnaces and Flues by the Use of Salts and Compounds, by P. Nicholls 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 of Combustion in the Steam Boiler F'urhace, 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 Research, Inc., Technical Report No. IV). Hand-Firing of Bituminous Coal in the 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 State Geo logical Survey Bulletin No. 62). . 352 CHAPTER 13 1952.Guide. 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. . 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 less Treatment. -Technical Report 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 F. K. Ovitz. ;. ; . . Report of Investigations (R. I. 2980), Coke as a Domestic Heating Fuel, by P. Nicholls and B. A. Landry. : . Technical Paper No. 303, Value 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. Nicholls. Handbook; Questions and Answers for the Home Fireman (Revised), by J. F. Bark - ley. Anthracite Industries Laboratories Publications:, : , . Report 2015, Comparison of Sizes, Egg, Stove and Chestnut-Anthracite. 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 Fuelsand Burners, by James A. Moyer (McGraw-Hill Co., 1937). . Handbook of Oil Burning, by Harry F. Tapp (American Oil Burner Association). Industrial Gas Series; Combustion-{American Gas Association). . . ,. Comfort Heating {American Gas Association). Gaseous Fuels {American Gas Association, 1948).Combustion {American Gas Association, 3rd Edition, 1932). Handbook of Oil Burning {Oil-Heat Institute of America, 1951). Formulas and Graphs for Representing the Interchangeability of Fuel Gases, by Elmer R. Weaver {National Bureau of Standards Journal of Research, 1951, Re search Paper R.P. 2193). .. ! CHAPTER 14 AUTOMATIC FUEL BURNING EQUIPMENT Classification of Stokers, Combustion Process and Adjustments, Furnace Design,. Rating; Classification of Oil Burners, Combustion Process, Combustion Chamber . Design; Classification . of Gas-Fired Heating Equipment, Combustion ' Process, Ratings; Sizing of Gas Piping, Fuel Burning Rates A UTOMATIC mechanical equipment' for the combustion of solid, XIL liquid, 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 at tractive 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 lignite coals, and coke. The U. S. Department of Commerce has issued commercial standards for household anthracite stokers.1 - Units are available in either the hopper type, as shown in Fig. T, or in the bin-feed type as shown in Figs. 2 and 3. Some stokers, particularly those designed for use with anthracite, automatically remove ash from the ash pit and deposit it in an ash receptacle as shown in Fig. 3. Most 353 354 CHAPTER 14 1952 Guide 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 bn 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 Fig. 1. Undebfbed Stokeb, Hoppeb Type, Class 1 fe Fig. 2. Undebfeed Stokeb, Bin Feed Type, Class 1 . furnaces, some of the combination stoker-fired units (Fig. 4) are more 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 sively for heating plants in apartments and hotels, also, for industrial plants. They are of the underfeed type and are available in both the hop per type, as illustrated in Fig. 5, and. the bin feed type, shown in Fig. 6. These units also are built in plunger feed type with an electric motor or 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 accord 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. Anthracite stokers in this class are equipped with moving grates which Automatic Fuel Burning Equipment 355 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 the 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 fuel in the combustion zone. As the temperature of the coal rises, it gives off moisture and occluded gases, which are largely non-combustibles. When the temperature increases to around 700 or 800 F the coal particles become plastic, the degree of plasticity varying with the type of coal. i 356 CHAPTER 14 1952 Guide Automatic Fuel Burning Equipment 357 Fig. 3. Underfeed Anthracite Stoker with Automatic Ash Removal, ,, Bin Type . Fig. 6. Underfeed Screw Stokbb, Bin Type, Class 2, 3 or 4 COAL COAL HOPPER AGITATOR Fig, 4.. Stoker-Fired Winter Air Conditioning Unit Fig. 7. Underfeed Side Cleaning Stoker . . A rapid evolution of the combustible volatile matter occurs during and directly after the plastic stage. The distillation of volatile matter con tinues above the plastic zone where the coal is coked. The strength and. porosity of the coke formed will vary according to the size and character 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 and, as this ash layer becomes thicker with time, that portion exposed to the higher, temperatures surrounding the retort fuses into a clinker. The i Fig. 8. Overfeed Traveling-Grate Stoker temperature in the fuel bed, the chemical composition and homogeneity f the ash, and the time of heating govern the degree of fusion. Most bituminous coal stokers of Classes 1, 2, 3 and 4 require manual removal of the ash in clinker form. 358 CHAPTER 14 1952 Guide - In the underfeed side-cleaning stokers the fuel is introduced at the fronts of the furnace tq one or more retorts, and is advanced away from the 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 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-rcleaning 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 359 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 bum the fuel at the rate of feed. . While there may be only slight variations in the rate at which the coal is being fed, due to variations in the size or density of the coal, there may be wide variations in the rate of air flow as the result of changes in fuel bed 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 coin- 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 ash 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-grate stoker is provided with an ash plate on which ash is accumulated and dumped periodically. This type of stoker is suitable for all types of coking 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 its agitating effect on the fuel, it is not desirable for badly clinkering coals. It usually should be provided with a front arch to ignite the volatile gases. Combustion Adjustments The coal feeding rate and air supplv to the stoker should be regulated sb 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, as explained in Chapters 13 and 49. . 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.* 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.) 360 CHAPTER 14 1952 Guide For burning rates from i00 to 1200 lb coal per hour H = 0.03 B'+ 24 where ~ . . , H = minimum setting height, inches, measured from dead plates to crown sheet . for steel boilers. For cast-iron boilers height may be | H. . B = burning rate coal per hour, pounds. Standards for minimum firebox dimensions and base heights have been formulated by the Stoker Manufacturers Association as shown in-Fig. 11.* 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 361 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 at times 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 the 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 38.) . 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 mri-ng coal 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 the boiler or furnace. Installation of stokers (particularly smaller sizes) on the side of the boiler or furnace will sometimes facilitate clinker removal- Rating and Sizing Stokers 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 been adopted by the Stoker Manufacturers Association.* The Association also has adopted a uniform method of selecting stokers that is published in convenient tables and charts.* The required capacity of the stoker is calculated as follows: Load (Btu per hour) Stoker burning rate = required (pounds of Heating value of coal (Btu per pound) X overall efficiency of coal per hour) stoker and boiler or furnace In determining the total load placed on a stoker-fired boiler by a steam 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 nous 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 uito the following groups: pressure atomizing or gun, rotary, and vapor izing or pot. These are further classified as mechanical draft, and natural draft. Pressure Atomizing (Gun Type) Burner Gun type burners may be divided into two classes: low-pressure and high-pressure atomization. In the first group, a mixture of oil and primary 362 CHAPTER 14 1952 Guide air is pumped as a spray through the nozzle at a pressure of 2 to 7 psi. Secondary air is supplied by a fan. Ignition is obtained by means of a high-voltage electric spark used alone, or as primary ignition for a gas pilot. Various features of a low pressure atomizing bumer'are shown, in Fig. 12. . The high-pressure atomizing type, illustrated in Fig. 13, is characterized by an air tube, usually horizontal, with oil supply pipe centrally 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. .' . This type of burner utilizes a fan to supply the air for combustion, and 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 Automatic Fuel Burning Equipment 363 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. . Horizontal rotary burners are used principally to bum the heavier oils, Nos. 5 and 6 grades, principally in larger commercial and industrial in stallations, allbough domestic sizes are available. Such burners are of the mechanical atomizing type,, using rotating cups which throw the oil from the edge of the cup at high velocity into the surrounding stream of air delivered by the blower (Fig. 16). Horizontal rotary burners commonly use a combination electric-gas ignition system, or are lighted manually. Primary air for combustion is supplied by a blower, and secondary air, often introduced through a Fig. 13. High-Pressure Atomizing Oil Burner running period. Gun type burners operate on the intermittent on-off . principle, and with a luminous flame. The combustion process is completed in a chamber constructed of refractory material, or stainless steel, this being a part ,of the installation. Pressure-atomizing burners generally use the distillate oils, No. 1 or 2 grade. (See Chapter 13.) Rotary Type Burner This class of burners may be divided into two groups: vertical and horizontal. Most of the smaller rotary burners are of the vertical type, and use a light distillate oil of No. 1 grade. The most distinguishing feature of vertical rotary burners is the principle of flame application. These burners are of two general types: the center flame and wall flame. In the former type (Fig. 14), the oil is atomized by being thrown from the rim of a revolving disc or cup, and the flame bums in suspension with a characteristic yellow color. Combustion is supported by means of a bowl-shaped chamber or hearth. The wall flame burner (Fig. 15) differs in that combustion takes place in a ring of stainless steel 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 i tbc5r V. .1 -% iSir X; Fig. 14. Center Flame Vertical Rotary Burner checkerwork in the combustion chamber, is controlled by chimney draft. These burners operate with a luminous flame, usually on high-low or continuous setting. In larger installations, burners may be installed in multiple in a common combustion chamber. Because of the high viscosity oils used in these burners, it is customary to preheat the oil between the tank and thebumer. Preheating when delivering from tank car, or truck, is often required in cold weather. Vaporizing Burners 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 additional or secondary air is admitted to complete combustion. The openings 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 is either 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 364 CHAPTER 14 1952 Guide Automatic Fuel Burning Equipment 365 I 4 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 be noted in such units; some having the combustion chamber and burner at the top, some at the bottom, and some at the center of the appliance. I One type of boiler-burner unit is shown in Fig. 18. The coordinated design of boiler (or furnace) and burner elements insures the optimum in | operating characteristics, and the maintenance of balanced performance. ft This type of equipment usually has more heating surface, and better flue t proportions and gas travel than conventional boilers or furnaces. Some pilot fire can be increased to give almost any desired control characteristic within the range of the burner. The majority of vaporizing burners are manufactured in sizes up to one gallon per hour input. Most vaporizing burners are limited to use with No. 1 fuel oil having a maximum end point of 625 F and a minimum A.P.I. gravity of 35 deg. A barometric draft regulator is required to maintain the recommended draft. A draft of not more than 0.06 in. of water column is recommended for most natural, draft burners. When burners are equipped with me chanical forced draft, a slightly lower chimney draft can be used. A burner of this type is illustrated in Fig. 17. Vaporizing burners are adaptable to water heaters, space heaters, and furnaces. Some types have also been applied successfully to conversion installations. The heat output is in the range of requirements for the average or small home. -The modulating flame allows simple manual control by regulation of a metering valve, and simplifies the control equipment. Quiet com bustion and the absence of moving parts contribute to quiet operation when the heating device is located in the living quarters. lt- SS- "t i, { I ! * r 17.Fig. 'Vaporizing Pot-Type Burner v V, f! I of the better conversion installations, however, may equal the unit type in performance. Operating Requirements for Oil Burners The U. S. Department of Commerce, in conjunction with the oil burner and heating appliance industries, has established commercial standards for conversion burners and burner-appliance units which cover' installation, construction and performance tests.4 Combustion Process Efficient combustion must produce a clean flame and use a relatively small excess of air, t'.e., between 25 and 50 percent. This can be done only by vaporizing the oil quickly and completely, and mixing it vigorously with air in a combustion chamber hot enough to support the combustion. A vaporizing burner prepares the oil for combustion by transforming the liquid fuel to the gaseous state by the application of heat before the oil vapor mixes with air to. any extent and, if the air and oil vapor tempera tures are high and the fire pot hot, a clear blue flame is produced. 366 CHAPTER 14 i952 Guide 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 bum 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 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, and 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 con stant, or an increase in oil delivery while the air supply remains constant, will make the mixture of oil and air too rich for clean combustion. The more efficient the adjustment, the more critical it will be. The oil and air supply rates must remain constant. The following factors may influence the oil delivery rate: (1) changes in oil viscosity due to temperature change or variations in grade of oil delivered; (2) erosion of atomizing nozzle; (3) fluctuations in by-pass relief pressures; and (4) possible variations in methods of atomization. Any change due to partial stoppage of oil delivery will increase the proportion 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 (t'.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 exceed 0.02-0.05 in. water. An automatic draft regulator is very helpful in maintaining such values. Even though a fan is generally used to supply the air for combustion, in most oil burners, the importance of a proper chimney should not be overlooked. The chimney should have sufficient height and size to insure that the draft will be uniform within the limits given, if maximum efficiency throughout the heating season is to be maintained. Automatic Fuel Burning Equipment 367 Measurement of the Efficiency of Combustion Since efficient combustion is based upon a clean flame and definite proportions of oil and air employed, it is possible to determine the results by analyzing the combustion gases. It is usually sufficient to analyze only for carbon dioxide (CO%). A showing of 10 to 12 percent indicates the best adjustment, if the flame is clean. Most of the good installations show from 8 to 10 percent COj. Taking into account the potential hazard of low excess air (high C02), a setting to give 10 percent COj constitutes treasonable standard for most 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 re fractory or firebrick 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. In this way as much firebrick as possible is close to the flame so it may be kept hot. This insures quick vaporization, rapid combustion and better mixing by eliminating dead spaces in the combustion chamber. An overhanging arch at the back of the fire pot is sometimes used to increase the flame travel and give more time for mixing and burning, and sometimes to prevent the gases from going too directly into the boiler flues. When good atomization and vigorous mixing are achieved by the burner, combustion chamber design becomes a less critical matter. Where secondary air is used, com bustion 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 in 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 1.5 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 much higher fuel rates may be satisfactory. For best results, care should be taken to keep the gas velocity below 40 fps. Where checkerwork of brick is used to provide secondary air, good practice calls for about 1 sq in. of opening for each pound of oil fired per hour. Such checkerwork is best 368 CHAPTER 14 1952 Guide adapted to flat flames, or to conical flames that can be spread'over the floor of the combustion chamber. The proper bricking of a large or even medium sized boiler for oil firing is important, and frequently it is advisable to 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 38. 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 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 and forced warm air funaces, steam, and hot water boilers are used, and for other applications where warm air floor furnaces and room heaters are installed in the space being heated. . Central Heating Systems . Boilers and furnaces specially designed for gas-firing incorporate design features for obtaining maximum efficiency and performance. Small flue passes to secure good heat transfer, the use of materials resistant to the corrosive effects of products of combustion, and draft hoods are notable features. Control equipment includes gas pressure regulators, automatic pilots, and limit controls designed to protect the appliance and to insure safety of operation. A boiler designed for gas-burning is illustrated in Fig. 19. . ` Conversion burners are usually complete burner and control units de signed for installation in existing boilers and furnaces. Burner heads are of circular or rectangular shape in order to fit in the space available. Single port burners, discharging the flame against a ceramic, stainless steel, or cast-iron target, have become popular in the past few years. The control equipment is generally the same as for gas boilers and fumaces. Various baffles made of clay radiants or metal are used for the purpose of guiding the products of combustion along the heating surface in the firebox or flues. Automatic air dampers are supplied on many models to prevent flow of air into the firebox when the burners is not operating. A typical gas conversion burner is shown in Fig. 20. Burners of this type are available in sizes ranging from 50,000 to 400,000 Btu per hour capacity. Burners of larger capacity, for use with natural gas in large boilers, are usually engineered by the local utility or contractor. They are available in an infinite number of sizes because the burner may be an assembly of multiple burner heads filling the entire firebox. Domestic sizes of conversion burners should conform to American Stand- f. i, S V h ft Jr Automatic Fuel Burning Equipment 369 ard Listing Requirements for Conversion Burners, A.S.A. Z21.17-1948, and installation should be made in accordance with American Standard Requirements for Installation of Domestic Gas Conversion Burners, A.S.A. Z21.8-1948.6 .... . Draft hoods, conforming to American Standard Requirements, should be installed in place of the dampers used with a solid fuel. . One form of central heating system is the warm air floor furnace.6 The 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-furnace applications, the heating element, gas piping, and flue vent piping are suspended below the floor, and the only part in the room. being heated is the circulating air register which may be of the single-type installed in the floor, or of the.dual-type installed in a partition, and heating two rooms. , A recent type of central heating, used in mild climates, is the recessed, heater which is either a gravity or forced-air furnace designed for installa tion in the interior partition of a building, and having stub ducts conduci ng air to two or more rooms. This type of heater is usually installed in new homes, and is plastered into the wall, becoming a permanent part of the building. Space Heaters . Space, heaters are defined as heating units that take the air for com-' bustion from the space being heated. They may be broadly classified as room heaters and unit heaters.. Room heaters are used for heating single rooms or connecting rooms with good circulation between them and, except for wall-type heaters, they E 370 CHAPTER 14 1952 Guide' are semi-portable. Unvented-type room heaters should not be used in residences, unless provision is made to remove the excess moisture caused by release of the flue gases into the living quarters. All types of room heaters are capable of automatic control, although they are generally con trolled 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 heaters, 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 hot 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. Wall healers, 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. Unit healers are used extensively for heating large spaces such as stores, . garages, and factories. These heaters consist of a burner, heat exchanger, fan for distributing the air, draft hood, automatic pilot, and controls for burners and fan. They are usually mounted in an elevated position from which the heated air is directed downward by louvers. Some unit heaters are suspended from the ceiling, and others are free-standing floor units of the heat tower type. . Unit heaters are available in two types, classified according to their use, with, or without ducts. Only those types of unit heaters tested and approved as warm air furnaces can be connected safely to ducts, as they have sufficient blower capacity to deliver an adequate air supply against duct resistance, and are equipped with limit controls. . 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 B V 'i % Automatic Fuel Burning Equipment 371 vided for moving the air through the system. Duct furnaces are tested for operation at much higher static pressures than are obtained in unit heaters. Combustion Process and Adjustments Most domestic gas burners are of the atmospheric injection (Bunsen) . type in which primary air is introduced and mixed with the gas in the throat of the mixing tube. A ratio of about 5 parts air to 1 part gas for manufactured gas, and a 10 to 1 ratio for natural gas, are generally used as theoretical values of air required for complete combustion. For normal operation of most atmospheric type burners, 40 to 60 percent of the theoretical value as primary air will give best operation. The amount of excess air required in practice depends upon several factors, notably: uniformity of air distribution and mixing, direction of gas travel from burner, and the height and temperature of combustion chamber. 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. 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. Little difficulty should be had in maintaining efficient combustion when burning gas. The fuel supply is normally held to close limits of variation in pressure and calorific value, and the rate of heat supply is nominally constant. Because the force necessary to introduce the fuel into the combustion chamber is an inherent factor of the fuel, no draft by the chimney is required for this purpose. The use of a draft hood insures the maintenance of constant low draft conditions in the combustion chamber with a resultant stability of air supply. A draft hood is also helpful in controlling the amount of excess air and preventing back drafts that might extinguish the flame. (See Chapter 13.) , _ Due to the use of draft hoods and gas pressure regulators, both the input and combustion conditions of gas appliances are maintained quite uniform until deposits of dirt, corrosion, or scale accumulate in the air inlet openings, burner ports, or on the heating surface. Periodic cleaning is necessary to keep any gas appliance in proper operating condition. Measurement of the Efficency of Combustion The efficiency of combustion may be judged from the percentage of carbon dioxide (COt), oxygen (Of) and carbon monoxide (CO) in the flue gases. The COj and 0% may be obtained by means of an Orsat apparatus, but the CO must be determined by more accurate equipment. It is customary to use simple indicators to determine whether CO is present, and to make adjustments of the appliances to reduce the CO below 4/100 of one percent before continuing tests in which the COt and Oj can then be found by use of the Orsat apparatus. Since the ultimate COt for any gas depends on the carbon-hydrogen ratio, the quality of the combustion 372 CHAPTER 14 1952 Guide :' ' ' . should not be judged from the value of the CO% in the flue gas without reference to the ultimate <70j obtainable. Practical values of COt will usually be from 8 to 14 percent, depending on the gas used. ' ->.>i. . > i 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. The tests are conducted at the A.O.A.Laboratories. Outputrating is determined from the approved input and an average efficiency stated. in the Approval Requirements, and is the heat available at the outlet. t i !' f r 7 Sizing Gas-Fired Heating Plants , Although gas-burning equipment usually is completely automatic, }r i Table 1. Capacity op Gas Piping Nominal Diameter of Pipe in Inches Length of Pipe m Feet *. 2 Capacity--Cu Ft Per Hr with a 0.6 Sp Gr Gas and Pressure Drop of 03* 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 I r t maintaining the temperature of rooms' at a predetermined figure, there are some manually controlled installations. In order to overcome effec tively the starting load and losses in piping, a manually-controlled gas boiler should have ah output as much as 100 percent greater than the equivalent standard radiation which it is expected to serve. Boilers under thermostatic control, however, are not 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 percent 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 15. 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. Automatic Fuel Burning Equipment 373 Installations 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 38. 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 Table 2. Multipliers for Various Specific Gravities For Use With Table 1 Specific Gravity Multiplier Specific Gravity Multiplier .35 1.31 1.00 .775 .40 1.23 1.10 .740 .45 1.16 1.20 .707 .50 1.10 1.30 .680 .55 1.04 1.40 .655 .60 1.00 1.50 .633 .65 .962 1.60 .612 .70 .926 1.70 .594 .75 .895 1.80 .577 .80 .867 1.90 .565 .85 .841 2.00 .547 .90 .817 2.10 535 undue loss of pressure between the point of supply (the meter) and the burner. The size of gas pipe required depends upon the following: 1. Maximum gas consumption to be provided. 2. Length of pipe and number of fittings. 3. Allowable loss in pressure from the outlet of the meter to the burner. 4. Specific gravity of the gas. `J . To obtain the cubic feet per hour of gas required by the burner, divide the Btu input at which the burner will be adjusted, by the average Btu heating value per cubic foot of the gas. Capacities of different sizes and lengths of pipe, in cubic feet per hour, with a pressure drop of 0.3 in. of water column for a gas of 0.60 sp gr, are shown in Table 1. In adopting a 0.3 in. pressure drop, due allowance for an ordinary number of fittings was made. To convert the figures given in Table 1 to capacities for another gas of different specific gravity, multiply the tabular values by the multipliers shown in Table 2. 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 Automatic Fuel Burning Equipment 374 CHAPTER 14 1952 Guide 375 GROSS OUTPUT - HUNDRED FEET STEAM RAOIATION t--i--i--i--i--i--r--i--i--i--i--i--i--i--i--r- --I---- 1--I--T" 5 JO 20 25 GROSS OUTPUT - HONORED FEET WATER. RAOIATTON Fig. 21. Coal Fuel Burning Rate Chart ii 30 Fig. 22. Oil Fuel.Burning Rate Chart* * This chart is based upon No. 2 oil having a beat content of 143,400 Btu per gallon. If other grades of 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. -' =*u k GROSS OUTPUT - HUNDRED FEET STEAM RAOIATION 1V I I--I--I--I-- I I--r--i--I--I--I--1--1--I--1--I--I--,--I--r--,--I--I--r--I--,--,--p- O 5 . to 20 26 30 GROSS OUTPUT-HUNDRED FEET WATER RAOIATION Fig. 23. Gas Fuel Burning Rate Chart 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 15, and for . warm air systems, in Chapters 18 and 19. 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 1 Domestic Burners for Pennsylvania Anthracite (Underfeed Type), (U. S. De partment of Commerce, National Bureau of Standards, Commercial Standard No. CS48-40). ' 1 * Stoker Manufacturers,Association Manual: Industry Standards, Recommended Practices, Technical Information. Published by Stoker Manufacturere 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. . 376 CHAPTER 14 1952 Guide - 4 Automatic Mechanical Draft Oil Burners Designed for Domestic Installations (U. S. Department of Commerce, National Bureau of Standards, Commercial Standard No. CS75-42). Flue Connected Oil Burning Space Heaters Equipped with Vaporiz ing Pot Type Burners (U. S. Department of Commerce, National Bureau of Standards, Commercial Standard No. CS101-43). Warm-Air Furnaces Equipped with Vaporiz ing Pot-Type Oil Burners (U...S. Department of Commerce, National Buredu of Stand ards, Commercial Standard No. CS104-46). Oil-Burning Floor Furnaces Equipped with Vaporizing Pot-Type Burners (I/. S. Department of Commerce, National Bureau of Standards, Commercial Standard No. CS113-44). 6 American Standard Requirements for Installation of Domestic Gas Conversion Burners (A.S.A. Z21.8-1948 American Standard Association). 8 Gas Floor Furnaces, Gravity Circulating Type (U. S. Department of Commerce,. National Bureau of Standards, Commercial Standard No. CS99-42). BIBLIOGRAPHY : Performance Expectancy of Domestic Underfeed Stokers for Anthracite, by Allen J. Johnson (Transactions, A.I.M.E., 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, E. R. Kaiser and H. R. Limbaeher, Technical Report No. 1, Bituminous Coal Research, Inc. (July, 1937) Part II. . Oil Fuels and Burners, by James A. Moyer (McGraw-Hill). Handbook of Oil Burning, by Harry F. Tapp. A Study of the Oil Burner as Applied to Domestic Heating, by Arthur H. Senner (Technical Bulletin 109, U. S. Department of Agriculture). - Progress in Domestic Oil Heating, by Rene J. Bender (Mechanical Engineering, October, 1942). . A.S.H.V.E. Research Report No. 907--Study of Performance Characteristics of Oil Burners and Low Pressure Heating Boilers, by L. E. Seeley and E. J. Tavanlar (A.S.H.V.E. Transactions, Vol. 37, 1931, p. 517). A.S.H.V.E. Research 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). Air Supply and Its Effect on Performance of Oil Burners and Heating Boilers, by L E. Seeley, J. H. Powers and E. J. Tavanlar (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 75). . Study of Fuel Burning Rates and Power Requirements of Oil Burners in Relation to Excess Air, by L. E. Seeley and E. J. Tavanlar (A.S.H.V.E. Transactions, Vol. 40, 1934, p. 319). Oil Burning in Residences, by D. W. Nelson (A.S.H.V.E. Transactions, Vol. 41, 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. Comfort Heating, American Gas Association. American Standard Approval Requirements of Central House Heating Gas Ap pliances, American Standards Association. A Method for Determining Fuel Burning Rates in Heating Boilers Fired by Auto 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). - CHAPTER 15 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 parts; the first dealing with boilers, the second treating warm air furnaces, and the third covering space heaters. HEATING BOILERS Steam and hot water boilers for low pressure heating are built of steel or cast-iron in a wide variety of types and sizes, many of which are illustrated 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 ASME Boiler Construction Code for Low Pressure Heating Boilers. Some states and municipalities have their own codes which apply locally, but these are usually patterned . after the A SME 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 few non-ferrous boilers are made. : ...... 2. According to the fuels for which the boilers are designed. These are coal, handfired or stoker-fired; oil; gas;.or wood. ..Some boilers are designed specifically for one fuel, but many boilers are designed for more than one fuel. 3. According to the specific purpose or application for which the boiler is used, such as space heating or domestic hot water supply. 4. According to the design or construction of the boiler such as sectional, round, fire-tube, water-tube, magazine feed, Scotch, etc. , : Cast-Iron Boilers . . .' , , Cast-iron boilers are generally classified as: '. . ,, 1. Square or rectangular boilers with vertical sections and rectangular grates, commonly known as sectional boilers. 2. Round boilers with horizontal pancake sections and circular grates. ' 377 ' 378 CHAPTER 15 1951 Guide i- 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. 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 summerwinter 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 web-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. There are a few boilers made with capacities up to 18,000 sq ft of steam radiation. For larger loads, boilers must be installed in multiple. - 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. Those with integral water jacketed furnaces are called portable firebox boilers, and are the most commonly used type. They are usually shipped in one piece, ready for piping connections. Refractory furnaces are usually installed in refractory lined furnace boilers after they axe 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 heated passes through the boiler, and as indirect, if the water heated does not come in contact with the water or steam in the boiler. .. Direct heaters are built to operate at the pressures found in city supply ' mains, and are tested at pressures from 200 to 300 lb per square inch. The life of - direct heaters depends almost entirely on the scale-forming properties of the water supplied and the temperatures maintained. If low water temperatures are maintained, the life of the heater will be much longer due to decreased scale formation and minimized corrosion. Direct water heaters in some cases are designed to burn refuse and garbage. Indirect heaters generally consist of steam boilers in connection with heat exchangers of the coil or tube types which transmit the heat from the Heating Boilers, Furnaces, Space Heaters 379 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. . 4. 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 13 and 14.) 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 eooled 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 op 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 Hie gas passages must not be so small as to cause excessive resistance , to the flow 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 draft loss through the boiler. ' Heat Transfer Rate . Practical average overall heat transfer rates, expressed in Btu absorbed per square foot of surface per hour, will average about 3300 for hand-fired boilers, and 4000 for mechanically-fired boilers when operating at design load. When mechanically-fired boilers are operating at maximum load, as defined in this chapter under heading Selection of Boilers, these values will run between 5000 and 6000. Boilers operating under favorable con ditions at these heat transfer rates, will give exit gas temperatures that 380 CHAPTER IS 1952 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. 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 for Rating Steam Heating Solid Fuel Hand-Fired 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,3 (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. The Steel Boiler Institute, Inc. has adopted a Rating Code for Com mercial Steel Boilers and Residential Steel Boilers, and for Testing OilFired Residential Steel Boilers (Fifth Edition as Revised Jan. 1, 1948). The commerical 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 Boilebs--Oil Fired" . .. Sq Ft Steam ! 275 320 400 550 700 900 1100 1300 1500 1800 2200 2600 3000 SBI 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 20.0 23.6 27.3 Heating Surface Sq Ft 16 19 24 32 41 53 65 77 - 88 106 129 153 177 * Stoker-fired and Gad-fired SBI Net Rating not greater than Oil-fired. Hand-fired, SBI Net Rating (Steam) not greater than 14 times the square feet of heating surface. is. ! t- % j 382 CHAPTER 15 1952 Guide I ' ' -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 boilers, respectively. The Institute of Boiler and Radiator Manufacturers has adopted a Code6 , for rating cast-iron heating boilers, based upon performance obtained under controlled test conditions. This Code applies to all sectional castiron heating boiler except, those of magazine-feed type. The Gross I -- B = R Output is obtained by test, and is subject to . certain limiting factors. For hand-fired boilers, the number of boilers of a series to be tested, the minimum overall efficiency, the minimum time limit, (the time an Available Fuel Charge will last when binned at a rate. which will produce the Gross / = B = R Output), the chimney area and height, and the draft in the stack are all subject to the limits established in tiie Code. Tests are run using anthracite coal of standard specification. Bituminous coal and coke ratings are the same as for anthracite coal. For automatically-fired boilers, the number of boilers of a series to be tested, the flue gas temperature and analysis, the minimum overall efficiency, the draft loss through the boiler, and the heat release in the- combustion chamber are subjected to limitation by the Code.6 Auto matically-fired boiler ratings are established by oil-fired tests using gun type oil burners and commercial grade . No. 2 fuel oil. Stoker-fired and gas-fired ratings (where no A.G.A. Rating is published) are based on the Gross 1= B=*R Output obtained by oil-fired tests. - The Net I = B -- R Rating is determined from the Gross I = B = R Output by applying specified Piping and Pickup Factors which range from 2.36 to 1.40 for hand-fired boilers, and from 1.56 to 1.288 for automaticallyfired steam boilers, and from 1.333 to 1.288 for automatically-fired hot water boilers. In all cases, the factor decreases as the boiler size in creases. Table 3 is abstracted from the 1951 I = B = R Boiler Rating Tables in the Code and illustrates the relationship between Net I = B = R Rating and Gross I = B = R Output. The American Gas Association rates gas designed boilers at 80 percent of the A.G.A. Input Rating. These ratings are determined by- per formance tests described in the A.G.A. Approval Requirements for Central Heating Appliances. The Heating, Piping and Air Conditioning Contractors National As sociation has adopted a method, based on their physical characteristics for rating boilers that are not rated in accordance with the SBI or I = B = R Codes. Ratings are expressed on a Net Load basis.in square feet of steam radiation. 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 absorbed by the water and steam in the boiler per pound of combustible burned on the grate, to the calorific value of 1 lb of combustible as fired. The combined efficiency of boiler, furnace and grate is the ratio of the heat absorbed by the water and steam in the boiler per pound of fuel as fired, to the calorific value of 1 lb of fuel as fired. r--' a 4n. i-1 ?C r> t T a b l e 3. = B = R B o il e r R a t in g T a b l e *I I -GBro-ssR ` O utput 1000 B tu Heating Boilers, Furnaces, Space Heaters 383 ' .X M inim um M axim um Stack Allow able Areab i D ra ft Loss In . W.O. 0.183 0.192 0.206 s ^o*oOoo Neooo5C*oIoO--o McoCoO--^cDo cDoNco oooooo OOOOOO ii s*. aH 0 .3 Pi 6 a o fJ c* <3 m N et; Steam W ater Steam 30a xy s . oOOoieOnOnNo03 wi3nDtoNcoOcoM-- o3'oC3>iC-40* h33.--co eao5 03 eo 3re----o 3ccoo0 o*3Q C*Dc CwD* O^O*9O* OOC30C3O0 COO 003- . 3-- GO DO ' CO ra oooc*o&* egooad> *ao>^cijj OCDCOGCOOCCGNDOC0OO0CCO0D0COGCOO 0GO03 OO03OO GGOO3 GOOO3 OGOOJ 0C0D3* 1.660 1.626 1.492 1.466 1.444 1.424 1.339 1.331 1.320 1.310 1.301 1.294 1.288 . 1.288 1.288 i 1.288 1 1.288 1.288 CO ' cCcooO cCcooO cCcooOceCoOo eCeOooCeraOo CO CO CO coco CO c CO COCO CO CO cecoo --ecoo occo* o--coc--Oo c0e3 CC3GTCOCDCCOOOMOOOOMOOOOOOCeOOi CCcOOcG0nO0 COnQOeGGOOcCOnOOD0O0O 16000 ! 18000 20000 oo--oo-Woot-ooOrooOoo oOc--koOc3oOc3Oot3tOoCiOoOC4O 3700 4000 4400 4800 6200 6600 ooOCD*ooCrDf*ooCoDooot--ooot3--ooo0o0 OooOoOoOoOoO 3a4o0a4o0c0cv0 00O I3'0O3OC--DS*O3* --eNo 'CcCoO ' O-CWD*CCDCOCOOCO0N3*G^-*HCGOD eeooc0od3c*0Do --eoecec*se*G^o* ^OC(ODCo0Oa4M0tOo0Co0C 8840 4320 4800 2040 2160 2280 2400 ' 2880 l 3360 3840 4320 4800 1440 1636 1632 . 1680 1800 1920 03 CD3 O-- cCoD *C4D* OCOO O-- DC^OD3C0OCCCODCOCDD C3DD-OCCOO M0039OC0DD33C00C3--0C*C409* 4< CO SSSggg Co3C--CCn3^C3CCDCeCoO 1000 B tu 1000 B tu 1 Sq' F t W ater ! I -CBro-ssR O utput 1000 B tu OO nO--DCDCDO^'Ti C^0r1Cn-cS00Oc0Oc3.mH0Oh-- OO--ODM--C0C3OD0D0'CO3OCNO 1858 1978 2102 2164 2318 2473 C0C0D3CC3GO-*O30--C33 G--coD30eO3-CCe-COo. sss 933 d-< N $ OOlOOOHM eOPCoDMoMNCn^CCoCO4NCDC. C0033OC3--O0C3C--OO OICDOOC(C-OO0CC3OO 0333 000^.-- 333353 N03D--DCOD30VCCO --3 caaiGoi-' 30--3oCGOOo0O3 Area oieoooo 301000030 30 o o too 30 0*0030 300 OOOOOO & O . 0CO3 0CO C-OO'-COD' 0-O3' CQO 3^C3QOtOot--CD CCOOC^D 0D 0<0030-3---3C-O3'C--* Cr-Dr3----r03-t0--3 --c--ooCsO cSSSSaccSS M axim um | M inim um Staok ! Staok 112.6 118.0 120.0 H eight 4.00 4.00 4.00 4.00 4.00 ; 4.00 Tim e A v a ila b le M- a i < .3 P ip in g and P ic k u p F a c to r Steam 8q F t Hr 4.00 4.00 4.00 100 400 700 1000 1300 1600 o . oDcCoOeto>cCoOoDcNo 0-- CD IO V - OCCOOOCD3t--CDO C0DONC0D3O0--31 CCCCCCMmm CO 1900 1.872 1 4.49 2200 1.837' ; 4.34 2600 1.806 4.24 2800 1.774 : 4.16 3100 j 1.744 1 4.07 3400 1.717 4.00 OoOoOoOooOoO oooooooooooo <' -- *** V * CDDOCDCCDOCOD IND 3D0 3Oc0cC3o0CoCeCtO-^NcD* oooooo 1.409 1.400 1.400 1.400 1.400 1.400 ! 3700 4000 4400 4800 6200 6600 oooooooooooo OCDVCDC0G3--O3D-OCO- oooooooooooo OCD O03 O03 OOOCOOW* 16000 18000 20000 ' .eo oC*CdDDOoInmoD> -- 3 CO CO coeooco*o*co oo q co e* a -r 00 030 -- co eo 0v^OnOnCOo9O0oG0Oc00t3 OOOOOO * CD GO O 00 CD O --CO*** CO CO OOO i sag CCC3CCC3CCD (Ovc1 Net I-B - Steam and w a te r 1000 B tu UOPcD.IcSOnCDOoOMoDMt. 864 970 1083 1192 1298 1401 o--3oo0--3on--i-va0--3ooC--oOneCocD 3-3--3DOOCO 030 -- 3-- OCQ --ccecc^n<e^ccccDc3--c tac-soNeoo --ooceoomOot-- OHO 3- W 3 3SB * E x tra c te d fro m R a tin g T a b le in 1961 e d itio n o f b T o be specified in catalog. Teatin g and R a tin g Code fo r Low Pressure Cast Iro n H eating Boilers* `, 384 CHAPTER IS 1952 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 steam in the boiler 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 . . In referring to boiler rating, it is necessary to know the basis on which .t he - rating has been established in order to understand the exact meaning of the term. The following example will illustrate the meaning of three ratings which might be established for the same boiler; . Assume that an installation has the following loads determined in accordance with the section Selection of Boilers: ` Net Load.................... '..................................... 1000 sq ft of steam radiation Piping Tax......................................................... 200 sq ft of steam radiation . Design Load................................. 1200 sq ft of steam radiation -. Pickup Allowance.............................................. 240 sq ft of steam radiation Maximum orGross Load....................... 1440 sq ft of steam radiation - : A boiler that is just large enough to carry this system might be said to ' have a net load rating of 1000 sq ft, a design load rating of 1200 sq ft, or a ... gross load rating of 1440 sq ft, depending on the basis on which the boiler is rated. ; On a net load basis the boiler would be rated 1000 sq ft of steam radiation .. and .would have sufficient excess capacity to supply the normal piping and pickup load. Net I=B--R Ratings, SBI Net Ratings, and Net Load ' Ratings of the Heating, Piping and Air Conditioning Contractors National ' Association are established on this basis. . 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 load. It would be of adequate size for a system in which the sum of the net load ~ and the piping heal loss did not exceed 1200 sq ft of steam radiation. The SBI Ratings shown in columns 1, 2, 3, 10, 11 and 12 of Table 2 (not to be confused with SBI Net Rating) are established on a design load basis. On & gross output basis of rating, the boiler would be rated 1440 sq ft of steam radiation and would be of adequate size for a system in which the sum of the net load, piping load, and pickup load did not exceed 1440 sq ft of steam radiation. Gross I=B = R Output and A.G.A. Ratings are established on a gross output basis. ' In the determination of boiler ratings, the Gross Output is the quantity of heat available at the boiler nozzle,. with the boiler normally insulated . and when operating under limitations stipulated in the code or method by. which the boiler is rated. The boiler may be capable of producing a greater nozzle output, but in doing so would exceed some of these limitations. Heating Boilers, Furnaces, Space Heaters 385 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 room in accordance with data given in Chapters 9,10 and 11. The sum of the calcu lated heat losses for all the rooms represents the total required heat emission of the 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. . ' / = 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 48. 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 sizes of installations, it is better to compute the heat emission from both bare and covered pipe surface in. accordance with data in Chapter 27. In average house heating systems, it is common practice to consider the piping tax to be equal to 25 percent of the Net Load. In determining Net I = B = R Ratings from Gross I = B = R Output, the piping factor allowed varies from 30 percent for small boilers to 12 percent for larger boilers. 4. Warming-Up or 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. Warming-up Allowances for Hand-Fired Low-Pressure Steam and Hot Water Heating Boilers" 0 DESIGN Load (RmiSOTmo Sumuation or Inna 1,2, and 3) Btu per Hour Up to 100,000 100,000 to 200,000 200,000 to 600,000 600,000 to 1,200,000 1,200,000 to 1,800,000 Above 1,800,000 Equivalent Square Feet of Radiation* Up to 420 420 to 840 840 to 2500 2500 to 5000 5000 to 7500 Above 7500 PSBCKNTAOS CAPACITY TO ADD roB Wabiuno-Upo ' 65 60 55 50 45 40 * This table is taken from the A.S.H.V.E. Code of Minimum Requirements for the Heating and Ventila tion of Buildings, except that the second column has been added for convenience in interpreting the design load in terms of equivalent square feet of radiation. b See also TimeAnalysis in Starting Heating Apparatus, by Ralph C. Taggart (A.S.H.V.E. Transac tions, Vol. 19, 1913, p. 292); Report of A.S.H.V.E. Continuing Committee on Codes for Testing and Rating Steam Heating Solid Fuel Boilers (A.S.H.VJ3 Transactions, Vol. 36, 1930, p. 35); Selecting the Right Sixe Heating Boiler, by Sabin Crocker (Heating, Piping and Air Conditioning, March, 1932). . e This table refers to hand-fired, solid fuel boilers. A factor of 20 percent over design load is adequate when automatically-fired fuels are used. - d 240 Btu per square foot. 386 CHAPTER 15 - / -* Other items to be considered in boiler selection are: 1952 Guide . Efficiency with hard or soft coal, gas, or oil firing, as the case may be. . 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. Height of water line. h. 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,* 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 Steel Boiler Institute, Inc. code, are intended to correspond with the estimated Table 5. Practical Combustion Rates fob Coal-Fired Heating Boilers Operating at Maximum Load on Natural Draft of from f in. . to 1 in. Water* . - - Kind of Coal No. 1 Buckwheat Anthracite Sq Ft Gsats Up to 4 5 to 9 10 to 14 15 to 19 20 to 25 Lb of Coal per Sq Ft , Grate per Hour 3 4m 5 Anthracite Pea Up to 9 10 to 19 20 to 25 5 5H 6 Anthracite Nut and Larger Up to 4 5 to 9 10 to 14 15 to 19 20 to 25 8 9 10 11 13 Bituminous Up to 4 5 to 14 15 and above. 9.5 12 15.5 * Steel boilerB usually have higher combustion rates for grate areas exceeding IS sq ft than those indi- eated in this table. . * 'Si- Heating Boilers, Furnaces, Space Heaters 387 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 SBI 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 expressedin 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 SBI 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 per formance tests are available, a good general rule for conventionally de signed 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: H G= CXFXE (1) where G = grate area, square feet. . H = required gross output of the boiler, Btu per hour (see Selection of Boilers). C = desirable combustion rate for fuel selected, pounds of dry coal per square foot of grate per hour (see Table.5). F = calorific value of fuel, Btu per pound. E = efficiency of boiler, usually taken as 0.60. Exarnple 1. Determine the grate area for a required gross outjrnt of the-boiler of 500,000 Btu per hour, a combustion rate of 6 lb per hour, a calorific value of 13,000 Btu per pound, and an efficiency of 60 percent. 500,000 G = 10.7 sq ft 6 X 13,000 X 0.60 The boiler selected should have a grate area not less than that determined by Equation 1. With small boilers, where it is desired to provide sufficient coal capacity for approximately an eight-hour firing period plus, a 20 per- 388 CHAPTER 15 1952 Guide cent reserve for igniting a new charge, more grate area may be required 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 on 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 the boiler water line is of vital importance. ' CONNECTIONS AND FITTINGS Steam outlet connections should be the full size of the manufacturers' tappings, in order to keep the velocity of flow through the outlet reasonably low, and to avoid fluctuation of the water line and undue entrainment of moisture, and should extend vertically to the maximum height available above the boiler. A steam velocity in boiler outlets not exceeding 25 to 30 fps at maximum load is recommended, unless data are available to show that a higher velocity is satisfactory. See further data on pipe connections to boilers in Chapters 20 and 21 and in the ASME Boiler Construction Code for Low Pressure Heating Boilers. Where a return header is used on a cast-iron sectional boiler 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 tions through the large plugged openings. An equivalent cleanout plug should be provided in the case of a single return connection. Blow-off or drain connections should be made near the boiler, and so arranged that the entire system may be drained of water by opening the drain cock. In the case of two or more boilers separate blow-off connec tions must be provided for each boiler, on the boiler side of the stop valve on the main return connection. Water service connections must be provided for both steam and water. Heating Boilers, Furnaces, Space Heaters 389 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 paper 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 surfacb 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 lo deliver enough heat. The cause of this condition may be: (a) poor draft; (6) poor fuel; (c) inferior attention or firing; (d) boiler too small; (e) im proper piping; (/) improper arrangement of sections; (g) heating surfaces covered with soot; (ft) insufficient radiation installed; and (i) with mechanical firing, fuel burning equipment too small. 2. The water line is unsteady. The cause of this condition may be: (a) grease and dirt in boiler; (6) water column connected to a very active section and, therefore, not showing actual water level in boiler; and (c) boiler operating at excessive rate of output. 3. Water disappears from the gage glass. This may be caused by: (a) priming due to grease and dirt in boiler; (ft) too great pressure difference between supply and 390 CHAPTER 15 1952 Guide return piping preventing return of condensation; (e) 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: (a) 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; (6) smoky combustion- (e) too low a rate of combustion; and (d) too much excess air in firebox causing chilling of gases. 7. Boiler smokes through fire 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; (c) improper fire caused by a fouled nozzle; or (d) to an insufficient quantity of oil being burned. Cleaning Boilers All boilers are provided with flue 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 pip .. ing systems serves as a carrier for sand and dirt, with the result.that a scum of fine particles and grease accumulates on the surface of the water in all new boilers, while heavier particles may settle to the bottom of the boiler ahd 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 1J 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 recedes, 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 10 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. Insoluble compounds have been developed which are effective, but special instructions on the proper cleaning compound and directions for its use, as given by the boiler manufacturer, should be carefully followed. Care of Idle Heating Boilers Heating boilers are often seriously damaged during summer months due chiefly to corrosion resulting from the combination of sulfur in the Heating Boilers, Furnaces, Space'Heaters\ 391: 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 depends upon the difference in density between the heated air leaving the top of the casing and cooled air entering the bottom of the casing. Since . this gravity head is relatively low, the furnace must have low internal re sistance to the flow of air, and relatively large areas must be available for free circulation within the furnace casing. It is common practice to pro vide approximately 50 percent free air area through gravity type furnaces. Furnaces for gravity type systems are available in designs suitable for central heating, pipeless furnace, or unit floor furnace installations. Booster fans are sometimes used in conjunction with gravity design systems, to in crease air circulation. Where a fan is to be used with a furnace casing sized for gravity air flow, some form of baffling must be emplpyed to re strict the free area within the casing and to force impingement of the air against the heating surfaces. Where square casings are used, the corners must be baffled. 392 CHAPTER 15 1952 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 33. 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 fur naces, 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 .in stallations so that the pressure in the air space is higher than that, in the combustion chamber or flues. The National Warm. Air Heating and Air Conditioning Association has prepared a Tentative Code for Testing and Rating of Oil-Fired Furnaces. Compact fan-furnace-burner -units are available, suitable for basement, closet, or. attic installations.. - 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 bat tery combinations of one or more units. Most manufacturers of heavy duty furnaces rate their furnaces in Btu Heating Boilers, Furnaces, Space Heaters 393 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 heat 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 29. Ducts are designed by the method outlined in Chapter 31. 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 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 of 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 may also be sectional in design, or may be combinations of common com bustion chambers and sectional or tubular radiation surfaces connected to a flue gas collector. Steel furnaces are made in capacities ranging from 40,000 Btu per hour to capacities as large as 600,000 Btu. Steel furnaces have low heat capacities as a result of their relatively low mass and, therefore, deliver heat rapidly on demand. FURNACE RATING Warm air furnaces are generally rated in Btu per hour output at the bonnet (point of heat generation) or at the register (point of heat delivery). 394 CHAPTER 15 1952 Guide Rating Equations for Gravity Warm Air Furnaces* Until a method of testing and rating gravity warm air furnaces has been developed, the following empirical rating equations are recommended by the National Warm Air Heating and Air'Conditioning Association. . Gravity warm-air furnaces of conventional design, having ratios (of heating surface to grate area) of 15 to 1 or greater,, and having a ratio of casing area to face area not less than 0.4, are rated by the following equa 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) 2. Hand-fired furnaces, with ratios of heating surface to grate area greater than IS to 1 and less than 95 to 1. . Bonnet Capacity in Btu per hour = 1785 X S X 1.333 (3) 3. Hand-fired furnaces with ratios of heating surface to grate area in excess of 95 to 1- ' Bonnet Capacity in Btu per hour = 1785 X 25 X G- X 1.333 (4) where S = heating surface, in square feet. G = actual grate area, in square feet. . The Register Delivery Rating is equal to 0.75 x (Bonnet Capacity). The Leader Pipe Rating in square inches, formerly used as a rating unit, may be jOund by dividing the Register Delivery Rating by 136. Heating Surface of Furnace Prime heating surface is defined* as surface above the top of the grate having hot gases or live fuel on one side and circulating air over the other, and in all cases is measured on the exterior or air'side. The areas of the outer casing, the inner liner, and any radiation shields shall not be considered as heating surface. . ,' In determining the amount of heating surface, extended surfaces are considered to be prime heating surface subject to the following limitations: 1. Extended heating surface may consist of fins, ribs, webs, lugs, or other pro jections from the prime heating surface. Projections less than i` in. thick at the base, and extending more than 1 in. from the prime Surface are classified as fins. 2. Integral fins are continuously welded to, or cast as a part of, the prime heating surface. Both sides are included as heating surface, subject to the following allow ances : Distance from Prime Surface . Ratio of Effective Area to 1st inch 0.40 2nd inch 0.30 3rd inch 0.20 Over 3 in. None 3. Non-integral fins are spot welded to, or otherwise held in line contact with the rime heating surface. Both sides are included as heating surface, subject to the allowing allowances: Distance from Prime Surface. Ratio of Effective Area to 1st inch 0.30 2nd inch 3rd inch 0.20 0.15 Over 3 in. None . Heating Boilers, Furnaces, Space Heaters 395 4. In the case of ribs, webs, or lugs more than 1 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 ease of ribs, webs, or lugs more than J 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 defined* 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 x S x 1.177 (5) 2. Hand-firedfurnaces, with ratios of heating surface to grate area greater than 15 to 1 and less than 95 to 1. Bonnet Capacity in Btu per hour = 2265 xS x 1.177 (6) 3. Hand-firedfurnaces with ratios of heating surface to grate area in excess of 95 to 1 Bonnet Capacity in Btu per hour = 2265 x 25 x G x 1177 (7) where S a heating surface, in square feet. ' G actual grate area, in square feet. The Register Delivery Rating is equal to 0.85 x (Bonnet Capacity). The following testing and rating codes have been generally accepted in the industry: . Commercial Standards CS-109-JU for rating solid fuel-burning, forced-air furnaces having bonnet outputs of 80,000 Btu per hour or less. This provides a method of rating small coal-fired forced-air furnaces by test. A Tentative Code for Testing Oil-Fired Furnaces. This code has been adopted by the National Warm Air Heating and Air Conditioning Association for rating oil-fired furnaces by test. The American Gas Association method of rating gas-fired furnaces on performance under tests. This is described in the 'Approval Requirements for Central Heating Gas Appliances. . ' 396 CHAPTER 15 1952 Guide Commercial Standards 11S-44 is a method of rating oil-burning floor furnaces by test. . Commercial Standards CS 104-46 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 Heating 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. Adeqyate heat transfer surface. 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 of fuel. 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. b. Regulation of the quantity and the distribution of the air for combustion should be provided by use of check dampers, draft regulators, draft hoods, air shutters and air orifices. c. Total draft loss through appliances should not exceed that available from chimneys which would normally be obtainable in the size of building which the appliance will supply with heat. d. The use of ignition safety devices such as safety pilots, hold-fire controls, and the like is recommended. 3. Fuel capacity of appliance. a. With solid fuels adequate coal capacity should be provided for at least 5 hr of operation at the maximum rated combustion rate. 4. Adequate circulation of air over heating surface. a. In gravity furnaces, free air space between casing and heat exchanger should be great enough to permit free flow over all surfaces. b. Forced air furnace design must include fans having proper capacity and suitable performance characteristics. Internal static pressures must be minimized without losing the advantages of high velocity circulation over the heat exchanger surfaces. c. The air .flow over the heating surface must be directed to obtain maximum efficiency and to eliminate hot spots and air noises. d. Air velocities at bonnet should not be much in excess of 1,000 fpm, and air temperature distribution at the furnace outlet should be uniform within approximately 30 deg. Heating Boilers, Furnaces, Space Heaters 397 5. Durability. a. A minimum metal weight for gas-fired heat exchangers is established as No. i 20U.S. Gage for plain carbon steel by the A.G.A. Approval Requirements for ' Central Heating Gas Appliances, with Borne municipal codes specifying 18 gage. Cast-iron sectional thicknesses of I in. to I 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 1 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 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 I in. flange is normally used for this purpose. . - d. Suitable provision should be made in appliances so that the controls and humidifiers may be installed in the proper location. When these auxiliary units are installed in the ductwork, detailed instructions should be provided to insure their proper location. e. The flue connection should be of integral flue pipe size, and provision should be made to attach the flue pipe to the flue outlet of the furnace. HUMIDIFICATION EQUIPMENT Evaporating pans are usually located in the outlet air. There is a present trend toward heating the water. Equipment for doing this may make use of sprays, or it may take the form of water circulating coils placed _ within the combustion chamber, and connected by pipes to the humidifier pans where a constant water level is maintained by some separate float device. All humidifiers require provision for removal of dirt and lime. 398 CHAPTER 15 1952 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) surfacefired and magazine-feed for solid fuels, (b) vaporizing pot-type and blue-ffame heater for oil, and (c) vented and unvented heaters for gas. (The type of gas burner de sign, 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 ' magazine-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 hitter 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 rating solid-fuel space heaters. A tentative procedure, TS-3443, has been issued by the Division of Trade Standards, National Bureau of Standards, but is 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 detennining the heater output, expressed in Btu per hour, by the indirect method. The measurable heat Heating Boile.rs, Furnaces, Space Heaters 399 losses: (1) loss due to moisture in the fuel, (2) loss due to heat in the dry flue gases, (3) loss due to unbumed carbon monoxide, and (4) loss due to .unbumed 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 unbumed 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 comer 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 may be accomplished by: (a) fabrication of certain parts from cast-iron or an alloy iron, (b) protection by a refractory liner, (c) use of high temperature enamel coat111gs, (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. Strength in 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 smokeless combustion is obtained by admitting secondary air through a narrow slot, extending from side to side, above the edge of the fuel bed where the gas leaves to enter a vertical gas passage.11 Complete mixing of the volatile material, released from the coal in the magazine, with the secondary air supplied is obtained as both streams pass under the bottom of the arch. Complete combustion results from this intimate mixing in a region which maintains itself at high temperatures even during banking periods. OIL HEATERS Vaporizing pot-type oil heaters consist of: (1) a metal pot in the bottom of which the oil is vaporized, the vapors burning at or near the top of the 400 CHAPTER 15 1952 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 vaporized, 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 13) 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 gen erally 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: Hr = A - B (8) and where. E - H,/A (9) A = total heat of fuel used. . B = heat lost in flue gases. H, = net heat delivered to the room. E = unit efficiency. The following minimum performance requirements are stipulated: I. Adequate provision for ease of lighting and insurance against loss of ignition prior to heating of burner. . 2. Ease of operation of controls. Heating Boilers, Furnaces, Space Heaters 401 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: 1. Proper pitch of oil lines from the sump to the burner, thus preventing vapor and air lock. . . 2. Proper positioning of the oil sump or constant-level valve to maintain the proper oil level in the burners, if factory 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 aseparate fuel tank is used, the heater should have provision for secure fastening to the floor to prevent excessive strain on 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 noncorrodible metal, or of metal suitably coated to resist corrosion. 8. The heater should have suitable baffling or insulation to prevent overheating of floors and walls. 9. Strength in assembly to prevent transportation 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.12 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 the gas. . Materials and Construction Standards covering materials and accessories used in the construction of gas heaters are described in ASA Approval Requirements for Gas-Fired Room Heaters1* and in applicable Listing Requirements.1* 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,12 based on the total heating value of the gas. Vented space heaters having input 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 basqd upon the following equation: . e, = 100 -- * X 100 (10) where q = hourly gas heat input, Btu per hour. Hf = heat above room temperature carried away by the flue products, Btu per hour. ` et = heating efficiency, percent. 402 CHAPTER 15 1952 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 dame 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. . i 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 16, Chimneys and Draft Calculations. In all cases, it is recom mended that installation be made in accordance with the current National Building Code. REFERENCES I See A.S.H.V.E. Transactions, Vol. 35,1929, pp. 332 and 332. 8 See A.S.H.V.E. Transactions, Vol. 36, 1930, p. 42. * See A.S.H.V.E. Transactions, Vol. 37,1931, p. 23. 4 See A.S.H.VJE. Transactions, Vol. 44, 1938, p. 366. ` I-B=R Testing and Rating Code for Low Pressure .Heating Boilers, 1950 (Insti tute of Boiler and Radiator Manufacturers). *I=B=R Ratings for Cast-Iron Boilers (Institute of Boiler and Radiator Manu facturers). . ' 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). i Recommended forms for municipal installation and fire codes are included in Manual 7--Code and Manual for design and Installation of Warm Air Winter Air Conditioning Systems, Second Edition, 1947 (National Warm Air Heating and Air Conditioning Association). II The Development of a Design of Smokeless Stove for Bituminous Coal, by B. ALandry and R. A. Sherman, presented at the 1948 Annual Meeting of the ASME. a 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, Z21.18. 1936, with addenda effective June 15,1935, July 8,1938, Automatic Main Gas-Control Valves, Z21.22, 1949 (American Standards Association). CHAPTER 16 CHIMNEYS AND DRAFT CALCULATIONS Theoretical Draft; Factors. Affecting Required Draft; Industrial Chimneys, Available Draft, Determining Chimney Size; Residential Chimneys, Available Draft, Determining Chimney Size; Draft Requirements of Residential Appliances; Chimneys for Gas Heating; Recommendations of the National Board of Fire Underwriters; General Considerations ADRAFT 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 atnospheric 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 the 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 will 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 fol lowing formula: 403 404 CHAPTER 16 1952 Guide where H = height of chimney, feet. . Bn = existing barometric pressure, inches of mercury. Wo = density of air at O F and 1 atmosphere pressure, pounds per cubic foot. Wc = 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 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. The efficiency of a chimney is defined as the ratio of the observed draft 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 gases traversed the chimney without cooling and without friction. The chimney efficiency may be calculated as follows: . final measured draft Efficiency = ., , , ,----- --- ----- ----------- -------------------------- ideal draft calculated from the inlet temperature (2) FACTORS AFFECTING REQUIRED DRAFT Before the proper chimney can be selected for an installation, the re quired draft of the combustion unit must be known. The required draft is, of course, equal to the sum of all the resistances to gas flow from the ash pit door to, and including, the.chimney connection. Fig. 1 presents information on the fuel-bed draft loss for various kinds Chimneys and Draft Calculations 405 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 31.) 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 li ft in diameter are in the industrial chinney 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 = 2.96 HB, (Wo _ c\ \T0 To) and for a rectangular stack: 0.00126vr*re/Z/ D`BoWo m 0.000388W^Tp/Lfe + y) ' (xyYBoWo where Do = 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 degrees, absolute. (4) 406 CHAPTER 16 1952 Guide " Tt = temperature of flue gas, Fahrenheit degrees, 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 elevation. . 2. The unit weight of a cubic foot of chimney gases at 0 F and sea level barometric pressure is given by the equation: JF,, = 0.131COt + 0.095Ot + 0.083N, (5) In this equation COt, Oi and Nt represent the percentages of the parts by volume of the carbon dioxide, oxygen and nitrogen content, respectively, of the gas analysis. For ordinary operating conditions, the value of Wt may be assumed at 0.09. ..The density effect on the chimney gases, due 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 top of the stack. This drop in temperature depends upon the material and construction 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:* 3.13T,{(tT-] r,, = tfb-3 (6) where . Ti = temperature at the center of the connection from the breeching, Fahrenheit degrees, absolute. . Hb = 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 condi 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, re 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 and convenience to the reader, this constant value of 0.016 has been employed in the de 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* in determining the friction factor, f. The following problem illustrates the use of Equation 3: Example 1: Determine the available draft of a natural draft chimney 200 ft in Chimneys and Draft Calculations 407 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 = 29.92 in. 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. /0.0863 Do = 2.96 X 200 X 29.92 X V 522 O09\ 960 ) 0.00126 X 100* X 960 X 0.016 X 200 10* X 29.92 X 0.09 = 1.27 - 0.14 = 1.13 in. Fig. 2 shows the variation in the 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 Fio. 2. Typical Set of Operating Characteristics of a Natural Draft Chimney tiie 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. 408 CHAPTER 16 1952 Guide DETERMINING INDUSTRIAL CHIMNEY SIZES If the required performance for a proposed chimney is known, and if a chimney-gas velocity is assumed. Equation 3 can be transposed to yield the necessary height, and an equation can be developed for the required diame ter. These operations result in the following equations: H= D,______________ WA _ 0.184/lVe-BoV2 tJ ~ TJ) (7) Fig. 3. Chimney Performance Chart . To solve a typical example: Proceed horizontally from a Weight Flow Rate point to intersection with diameter line; from this intersection fol- ' 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. DWB0WC The weight of gas per second, W = 12.075 from which Tc D = 0.288 A / WT-- T BJV'V where . H = required height of chimney above grate, feet. D = required minimum diameter of chimney, feet. V -- chimney gas velocity, feet per second. Z)r = total required draft, inches of water. - (8) For large chimneys, it is usual to assume that total construction cost Chimneys and Draft Calculations 409 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: where F, => 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................................. Tc = 960 F absolute Average atmospheric temperature 62 F....................................T0 = 522 F absolute Average coefficient of friction 0.016.............................................. / = 0.016 Average chimney, gas density, 0 F, 1 Atmosphere................. Ws = 0.09 lb per cu ft Barometer reading, sea level......................................................B0 - 29.92 in. Hg When these values are substituted in Equations 7, 8 and 9, respectively, the results are: ', H = 1900, (10) D = 1.5W`,S (11) F. = 13.7WV` (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' Handbook* or the Handbook of Building. Construction.* 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. The chimney height and location that are best suited to a building, from an architectural standpoint, will sometimes be unsatisfactory for the proper operation of the heating equipment. Chimney height is likely to be critical in one-story ranch-type or rambler-type houses, and therefore, it is im portant to compare carefully the available draft of the chimney and the required draft of the heating appliance to determine whether or not they will operate together satisfactorily. Most residential chimneys are constructed of brick with a clay flue liner, but recently several lightweight, prefabricated chimneys have been mar keted. These chimneys were primarily designed for use with gas equip ment, but recently several have been approved by the National Board of Fire Underwriters for use with all types of fuels. The advantages of the lightweight, prefabricated chimney are ease of installation, somewhat lower cost, and reduced weight on the supporting structure. 410 CHAPTER 16 1952 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 X. *l. U-. Chimneys and Draft Calculations 411 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 maYrmiim 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. HEIGHT OF CHIMNEY ABOVE CENTER LINE OF THIMBLE-FEET 4. 9* 9* 9* x 13'Fig. Available Draft fob x and Masonry Chimneys (Ambient Temperature 0 F) ambient temperature of 60 F. The available drafts produced by 9 X. 9-in. and 9 X 13-in. masonry chimneys are equal for practiced purposes over the range of mass flow from 83 to 300 lb per hr.* In tests of these chimneys the smaller chimney produced slightly greater drafts in the lower end of the range of mass flow rates whereas the larger chimney produced slightly higher drafts in the upper end of the range! . The chimney height for heating plants that operate on an on-off or high- fire 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 chimney height should be selected from Fig. 4 which shows the available draft for an outdoor temperature of 0 F since this is likely to be the more.critical cpndition with respect to chimney draft. The available draft for outdoor temperatures between 0 F and 60 F can be obtained by interpolation from Figs. 4 and 5 with only slight error. . HEIGHT OF CHIMNEY ABOVE CENTER LINE OF THIMBLE - FEET 5. 9" x 9' 9' x 13'Fig. Available Draft fob and Masonry Chimneys (Ambient Temperature 60 F) The available draft may be expressed as: where D. = nj), .' (13) nc = chimney efficiency taken from Fig. 7 at the desired conditions of tempera ture and flow. Di = ideal draft, calculated from Equation 14, assuming that the barometric pressure is 29.92 in Hg, and the ambient temperature is 60 F. ' . Di = 0.25541?off Q- - i-) (14) where Ba = barometric pressure, inches of mercury. H = chimney height, feet. Ti = chimney inlet temperature, Fahrenheit degrees, absolute. To = ambient air temperature, Fahrenheit degrees, absolute. 412 CIHA' PTER 16 1952 Guide 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 ' There are several lightweight chimneys that have recently been approved by the National Board of Fire Underwriters for use with all types of fuel. These chimneys are constructed of precast masonry or vitreous enameled steel surrounded by an insulating material. The characteristics of these chimneys can be assumed to be approximately those presented in Figs. 4 and 5. 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 tor gas-burning Chimneys and Draft Calculations 413 chimney from Figs. 6, 7 and 8. This solution can be best explained by a numerical example. , Example 8: Determine if a 13-ft, 8 x 8-in. nominal-size flue is sufficient lor 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 COj. . Solution: From Fig. 8, a flue'-gas rate of approximately 180 lb per hr is obtained. The available draft for a 180 lb per hr fuel rate, and 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-buming 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 FLUE-CAS FLOW-POUNDS PER HR Fig. 6. Available Chimney Draft for 13 Ft Brick Chimney*' 6 * Square Flue Liner x 6t in. inside. b Barometric Pressure 29.92 in. Hg. Air Temperature 60F. - 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 termine whether the chimney is adequate in height for the particular heating unit it serves. For calculations where the fuel rate and the percentage CO2 are the only known factors, the flue-gas rate can easily be determined for coal, oil and gas from Fig. 8. By entering Fig. 8 at the percentage C0%, moving verti cally to the curve for the type of fuel, and then moving horizontally to the fuel rate, the flue-gas rate in pounds per hour may be determined for any fuel.7 Any of the described methods of determining available draft may be used, but a graphical solution to the problem may be had for the 8 X 8-in. Fig. 7. Effect of Gas Flow on Chimney Efficiency* * Derived from temperature plots. Liner 8 x 8 in. outside, 6} x 6* inside. Height 13 ft. 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 effect9 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 tests8'10 on several chimneys with liners having nominal outside dimensions: 9 in. diameter, 12 in. diameter, 9X9 in., and 9 X 13 in. These tests showed that for flue gas rates up to 200 lb per hr, and entering flue gas temperatures from 200 to 1000 F, the 9-in. round liner provided an 414 CHAPTER 16 1952 Guide '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 ehtCnhg flue gas temperatures above 600 F. '- Table 1 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 chimney is best suited to mass flow rates from 130 to 170 lb per hr, a 9 X 9-in. chimney performs best for flow rates from about 200 to 300 lb per hr, and a 9 X 13 in. and 12 in. round chimneys are best suited to flow rates above 300 lb per hr.. These results were obtained with clean chimneys, so that conclusions about chimney areas require some modification if soot deposits are taken into consideration. _ Soot deposits in chimneys reduce' the effective area of the finer and may in some cases entirely close the passage. Soot deposits are likely to be FUIE CAS FLOW-POUNDS PER HR Fig. 8. Graphical Evaluation op Rate of Flue Gas Flow from Percent COt and Fuel Rate* * Average density gas 0.045 lb per cu ft, 62 F. Average weight oil 7.08 lb per gal, 60 F. greater in the horizontal passages in the heating plant, the breeching, and the smokepipe, than in the vertical chimney finer. An increase in the liner diameter of one inch above that required for a clean chimney will probably make adequate allowance for soot deposits in all but the worst cases. Where smoky combustion is likely to occur and the mass flow rates on a clean chimney basis approach those listed in Table 1, 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 hot 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 Chimneys and Draft Calculations 415 Table 1. Approximate Flue-Gas Flow Rates for Maximum Available Draft in Masonry Chimneys Nominal External Lines Dimensions Internal Abba op Lines, Sq In 9 in. Dia. 9 in. x 9 in. 12 in. Dia. 9 in. x 13 in. 38.5 49 78.5 77 200 Flue Gas Temperature at Ckimnet Inlet, Fahb. 600 1000 200 600 ..1000 Mass FloW Rate, LB/HR Flue Gas Velocity at Chimney . Inlet, FPM 170 150 130 175 250 300 215 306 . 334 175 400 600 290 Above Above 150 ___ 320 320 295 Above Above 150 ___ -- 320 320 finings, 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 speedy minimum areas based on the older dimensions. ' DRAFT REQUIREMENTS OF APPLIANCES Typical flue-gas temperatures and drafts required at rated output for several kinds of domestic heating appliances11 are contained in Table 2. 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 burners and stokers are equipped with blowers, and therefore, the chimney is not required to overcome the resistance of the fuel bed or burner. Nevertheless, a draft in the firebox, of about 0.03 in. of water, is considered desirable so that any small openings in the firebox or flue passages will result in leakage of air inward, and not leakage of combustion products outward. Firebox leakage should be kept to a minimum, however, since such leakage adversely affects heating plant efficiency. Difficulty in obtaining enough draft for natural draft appliances is likely to occur for attic installations or in one-story houses without basements. Automatic oil-burning space heaters, floor furnaces, and warm air furnaces employing natural-draft vaporizing burners require a draft of 0.06 to 0.08 Table 2. Drafts Required by Typical Residential -Heating Devices or Appliances . Device Draft, Inches Water Stack Tempera ture0 F Deg Space Heater, Oil Burning, Pot Burner....................... Warm Air Furnace, Oil Burning, Pot Burner............. Warm Air Furnace, Hand Fired.................................... Floor Furnace. Oil Burning, Pot Burner..................... Mechanical Oil Burner, Less than 5 gph..................... Mechanical Oil Burner, More than 5 gph....... ... Cooking Stove, Solid Fuel................ .............. . Space Heater, Coal Burning......................................... 0.06 to 0.08 0.06 0.06** 0.06 0.03* 0.04b 0.06b 1000 860 900 860 _ 400 900 * Draft in firebox. 8 For chestnut sired anthracite. B 18 in. from heater. 416 CHAPTER 16 1952 Guide in. water for outdoor temperatures of 60 F. Taking into account the' temperature drop of the flue gases between heater and chimney, Fig. 5 shows that an effective chimney height of 10 to 13 ft above the center line' of the thimble is the minimum that should be employed for these types of equipment. Coal-burning heaters and furnaces that are required to attain rated output at a design outdoor temperature of 0 F would probably per form satisfactorily with an effective chimney height of about 8 ft as shown in'. Fig.. 4. Application of adequate insulation to the smokepipe and breeching, might reduce these minimum values by 1 to 2 ft. When these Chimneys and Draft Calculations 417 less than 15 ft, since most barometric dampers permit enough cold air to' leak into the chimney even in the closed position to reduce the draft appreciably. 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 Btu input of the appliance. The chimney sizes adopted by Fig. 9. Capacity in Btu peb Hour fob Gas Appliance Flues ob Vents minimum chimney heights cannot be provided for architectural reasons or where flue gas temperatures lower than those shown in Table 2 exist, forced draft or induced draft should be employed. Since most residential heat ing plants are not designed for pressurized combustion chambers, forced draft should be used only to overcome the fuel bed or burner friction un-. less it is known that the plant has been constructed with no possibility of leakage in the combustion chamber and flue gas passages. The use of barometric dampers in the smokepipe of natural-draft oil heating appliances employing vaporizing burners, is not recommended when these appliances are connected to chimneys having effective heights o6Sk 15 _ oJ*U5z hi o 5 PER CENT INCREASE IN CAPACITY OYER CIRCULAR TLUE Fig. 10. Capacity of a Rectangular Flue or a Semi-Elliptical Flue, with Semi-Circulab Ends Having Its Minimum Width . Equal to the Diameter of a Circular Flue, Compared . with the Capacity of the Circular Flue the American Standards Association and the National Board of Fire Un derwriters in 1950 for gas appliances12 are shown in Fig. 9. Additional provisions of ASA Standard Z21.30-1950 relating to chimney size are: 1. In no case shall the vent area be less than the area of a 3-in. diameter pipe. 2. When more than one appliance vents into a flue or vent, the flue or vent area shall be not less than the area of the largest flue or vent connector plus 50 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 capacity is equal to the capacity of the round pipe for which it is substituted. Since Fig. 9 has been prepared for circular flues, relative capacities for rectangular and semi-elliptical flues13 are shown in Fig. 10. 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 418 CHAPTER 16 1952 Guide 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 Associalion and the American Standards Association, and is essential for safe 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 to 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 3-ft chimney. As the draft hood is designed without moving parts, the relief opening is always open, and consequently some air is drawn into the chimney. This air lowers the gas temperature in the chimney, but it also lowers the dew-point of the gases and tends to prevent condensation. The installation of conversion burner equipment in large boilers is usually made in accordance with regulations of the local gas company. In such installations a definite chimney draft may be required for proper combustion, and consequently the foregoing reference to the use of draft hoods would not apply. The products of complete combustion of gas are water vapor (fliO) and carbon dioxide (COt)., 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. Hie 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 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 be made to the National Building Code, recommended by the National Board of Fire Underwriters, Article X, Section 1001 to 1006, in which the following are some of the important provisions listed in the 1951 edition: 1. Flue Connections Required. Every heating apparatus or heat producing ap pliance requiring a flue connection shall be connected with a flue conforming to the provisions of this article. This shall not include electric appliances; gas appliances, except as specifically required in this article; nor oil fired appliances especially de signed for use without flue connection. 2. Use of Nonconforming Flues. Flues not conforming to the requirements of this article for chimneys, metal smokestacks or vents for gas appliances, shall not be used unless listed by Underwriters' Laboratories, Inc., installed in full compliance with the 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 piipe connections in more than one story'of a building, Chimneys and Draft Calculations 419 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 rriay equal the wall thickness. In every case the corbeling shall not exceed 1 in. projection for each course of brick projected. _ . e. No change in the size or shape of a chimney, where the chimney passes through the roof, shall be made within a distance of 6 in. above or below the roof joists or rafters. 5. Chimneys for Heating Appliances, Low Heat Industrial Appliances and Portable Type Incinerators. a. Chimneys for stoves, cooking ranges, warm air, hot water and low. pressure steam heating furnaces, fireplaces, and low heat industrial appliances, other than chimneys for incinerators of nonportable type, shall be constructed of solid masonry units or of reinforced concrete. The walls shall be properly bonded or tied with corrosion-resistant metal anchors. In dwellings and buildings of like heating 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 lin ,. ing conforming to the requirements below. . c. Flue linings shall be made of fire day or other refractory day which Will with stand the action of flue gases and resist, without softening or cracking, the tempera tures to which they will be subjected, but not less than 2000 F. Flue linings may be of cast iron of approved quality, form and construction. _ d. Required day flue linings shall be not less than | in. thick for the smaller flues, and shall increase in thickness for the larger flues. e. Flue linings shall be installed ahead of the construction of the chimney as it is carried up, carefully bedded one on the other in Type A, Type B, or fire clay mortar with close fitting joints left smooth on'the inside. . f. Flue linings shall start from a point not less than 8 in. below the intake, or, in the case of fireplaces, from the throat of the fireplace. They shall extend, as nearly vertically as possible, for the entire height of the chimney, and be extended 4 in. above the top of cap of the chimney. g. Cleanouts for flues or fireplaces shall be equipped with cast-iron doors and frames arranged to remain tightly closed when not in use. h. When two or more flues are contained in the same chimney, at least every third flue shall be separated by masonry at least 4 in. thick bonded mto the masonry wall of the chimney. Where flue linings are not so separated, the joints of adjacent flue linings shall be staggered at least 7 in. 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 lin'ed 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 420 CHAPTER 16 1952 Guide 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. 9 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. . 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 noods. 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 chimneys14 made of a variety of materials have developed additional recommendations regarding the construction of masonry chimneys that will decrease the hazard to surrounding combusti ble materials. GENERAL CONSIDERATIONS FOR CHIMNEYS The draft of domestic chimneys may be subject to a variety of influences not usually encountered in power chimneys15 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. How 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 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 cine 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. Chimneys and Draft Calculations 421 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, but if blowing in the opposite direction,, the draft may be decreased. The surrounding of a heating appliance with a restrictive enclosure that will limit entrance of combustion air is more likely to occur in a small utility closet installation on the first floor than in a basement installation. An opening with a free area approximately twice the area of the smokepipe 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 or cooking stove and a water heater with the same chimney flue. This is not 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. Gas burning devices, with their draft hoods and lack of draft dampers, are especially bad in this respect. The traditional method of avoiding this with brick chimneys has been to construct multiple-flue chimneys, so that each fuel-burning device could be served by a separate opening. If two devices must be served by one flue-opening in a chimney, their connections 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 ceding, so that each device can be serviced as well as possible, regardless of the treatment of the other. Excessive height in a chimney does no harm, but means for controlling the draft are more than ordinarily essential if the chimney is too large in capacity. Coal-burning devices often have air leaks around the firebox, and the draft doors sometimes fit so poorly that the fire cannot be con trolled 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. 422 CHAPTER 16 1952 Guide 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 in 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). .. Friction Factors for Pipe Flow, by L. F. Moody (AJ3MJB. Transactions, Vol. 66, 1944, p.671). . 4 Mechanical Engineers1 Handbook, Eleventh Edition, by R. T. Rent, Editor in Chief (John Wiley and Sons, Inc.). Handbook of Building Construction, by G. A. Hool and N. C. Johnson (McGraw- Hill Book Co., Inc, New York, 1929). 4 Observed Performance of Some Experimental Chimneys, by R. S. Dill, P. R. Achenbach and J. T. Duck (A.S.H.VJE. Transactions, Vol. 48, 1942, p. 351). 1 Performance of Residential Chimneys, by L. B. Schmitt and R. B. Erigdahl (A.S-H.V-E. Journal Section, Heating, Piping and Air Conditioning, November 1948,p. 111). ... Performance of Fourteen Masonry Chimneys Under Steady State Conditions, by P. R. Achenbach and S. D. Cole (A.S.H.VE. Journal Section, Heating, Piping and Air Conditioning, October 1948, p. 119). Physics of Chimneys; by P. R. Achenbach. (Physics Today, Vol. 2, No. 12, Dec. 1949). it Performance of Masonry Chimneys for Houses, by Robert K. Thulman (Hous ing and Home Finance Agency, Technical Paper No. IS, Aug. 1949). u National Bureau of Standards Commercial Standards: CS101-43 Oil-Burning Space Heaters Equipped With Vaporising Pot-Type Burners, CS7542 Automatic Mechan ical Oil Burners Designed for Domestic Installations, CS(E)104-43 Warm Air Fur naces Equipped With Vaporising Pot-Type Burners; CSKW^ Solid-Fuel Burning Forced Air Furnaces, CS113-44 Oil-Burning Floor Furnaces Equipped With Vapor ising Pot-Type Burners. " American Standard Installation of Gas Piping and Gas Appliances in Build ings (American Standards Association, Z21.30-1950). . . u Comfort Heating, 1938, p- 71 (American Gas Association). 14 Fire Hazard Tests with Masonry Chimneys, by Nolan D. Mitchell (National Fire Protection Association Quarterly, Oct. 1949). is Chimneys and Draft (Chapter 32 in Winter Air Conditioning, by S. Konzo, pub lished by National Warm Air Heating and Air Conditioning Association, 1939). CHAPTER 17 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; 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 useful in 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 past 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 heat 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 nrmsnin.1 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 is 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 methods in common use will give trustworthy rekilts over a full annual heating season, and in some cases such estimates will prove consistent within themselves for monthly periods. As the period of the estimate is shortened, there is more chance that some factor not allowed for in the estimating method will 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 methods are based upon an estimate of seasonal efficiency. The former is also based upon an estimate of average seasonal temperature. Neither method takes into account factors which are difficult to evaluate, such as 423 . 424 CHAPTER 17 1952 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 wiU .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 fights, 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 summary3 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. . 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 Sea sonal Efficiency, 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 with- out controls............................. Anthracite, stoker-fired........... Coke, hand-fired with con- trols........................................... Coke, hand-fired without con- trols........................................... Direct electric heating............. 60-80 50-65 60-80 60-80 50-65 100 .Estimating Fuel Consumption for Space Heating 425 CALCULATED HEAT LOSS METHOD In the Calculated HeatrLoss 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 11. 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 done, 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 11, for U. S. and Canadian cities. ................ Computation and Application ;' In order to apply the Calculated Heat-Doss Method, the hourly heat loss from the building under maximum ' load, or design condition, is com puted following the principles discussed in Chapters 9, 10, and 11. The fuel: requirement is then computed by.the equation , ,. ,, g(t - ON . " W* - t0)C ; (1) where ` 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 f,, and (j. ` l = average inside temperature maintained during heating period, Fahrenheit degrees. ... t* = average outside temperature through estimate period, Fahrenheit degrees (for cities with an.Oct. 1-May 1 heating season--see Table 1, Chapter 11). ' <d = inside design temperature, Fahrenheit degrees (usually 70 F). t0 = outside design temperature, Fahrenheit degrees (see Table 1 in Chapter 11). IV .= .number of heating hours in estimate period (for ah Oct. 1-May 1 heating . Beason, 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 thin 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. Example 1: A residence building is to be heated to 70 F from 6 a.m. to 10p.ih. and 65 F from 10 p.m. to 6 a.m. The calculated hourly heat loss is 120,000 Btu per hour based on 70 F inside at --10 F outside. If the building is to be heated by metered steam, how many pounds would be required during an average heating season? Solution: The heating value of steam may be taken as 1000 Btu per lb, and since it is purchased steam, the efficiency can be assumed as 100 percent. Assume average outside temperature as 36.4 F. The average inside temperature is: (16 X 70) + (8 X 65) _ 24 426 CHAPTER 17 1952 Guide Substituting in Equation 1 ' - 120,000 (68.3 - 36-4) 5088 = m m 1.00[70-(-10)11000 Example 2: What would be the fuel cost to heat' the building in Example 1 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 F = 28,800 lb. 0.65[70 - (-10)113,000 The fuel cost is then (28,800 H- 2000) (14) = $201.00 : Example 3: 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 F, 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 11 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 doors. . Solution: The average hourly temperature is (72 X 16) + (65 X 8) f, = 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 M ~ 100,000 X 0.80 X (72 - 0) 2697 hundred thousand Btu. 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 developed* which makes pos sible a quick solution if the gross wall, ceiling, or floor areas and respective transmission coefficients are known. The Federal Housing A dminislration 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 developed to apply to detached houses approximately rectangular in shape with total exterior door and window areas equal to about 25 percent of the floor area, and with a floor area not greater than about 1500 sq ft. Equation 2 is for a one-story residence, and Equation 3 is intended for two-story stmctures. Ei = A {G -f* Uw + U0 -(- Iff) (f<j -- O (2) Ht = A (G + 112 17. + 0MUc + 05 Vi) (fd - to) (3) Estimating Fuel Consumption for Space Heating 427 where . .. Hi = heat loss from one-story residence, Btu per hour. Hi -- 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 on 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). Um = coefficient of transmission for outside wall. Uc = coefficient of. transmission for ceiling. Ut = coefficient of transmission for floor. : id = inside design temperature, Fahrenheit degrees. - to -- outside design temperature, Fahrenheit degrees. . . Notes for application of Equations 2 and 3. 1. The calculation of heat loss from heated spaces into adjacent spaces such as attics, basementless 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 Ut = 0. 3. For structures having concrete slab floors laid on the ground a modified appli cation of the formula may be made. Assume Ut -- 0 and calculate the heat loss in accordance with the check formula. Then add the slab loss determined in accordance with the procedure developed by the National Bureau of Standards and described in 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 method and short-cut 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 11 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. The American Gas Association10 determined from records in the heating of residences that the gas consumption varied directly as the degree-days, or 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, twice as much gas was consumed as on a day when the temperature was 10 428 CHAPTER 17 1952 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. Degreedays may be calculated on other than the 65 F base, but are seldom used and are of little value except for example, in warehouses, where the inside temperature to be maintained differs greatly from the usual inside temper ature range of 68 F to 72 F. Studies made by the National 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, Canada and Newfoundland. The values 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 averageswere 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 by the degree-day method is: . ' F = U X N X D X C, (4) where F = fuel consumption for the estimate period. U = unit fuel consumption, or quantity of fuel used per (degree-day) (building load unit). N = number of 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 429 Table 2. Average Monthly and Yearly Degree-Days for Cities in the United States, Canada and Newfoundland*' b (Base 65F) State Station * , C8 3 iYears oo.cB<a oSfc > g Z *- 6 p <5 E CaO >o Z da Q i nH fa 3 a e> < h < a 2 P-9 '3S Eo* hR 5* Ala.... -Anniston............. 05/08-40/41 36 Birmingham___I 98/99-45/4( . 48 Mobile................. 98/99-45/46 48 - Montgomery.;... 98/99-45/46 48 Aria. .. Flagstaff............... 98/99-40/4] 43 . Phoenix................ 98/99-45/41 48 Yuma................... 98/99-40/41 45/46 44 Ark.... Bentonville...... 06/07-40/41 35 - Fort Smith.... .A 98/99-45/41 48 Little Rock.....A 98/99-45/41 48 Calif... Eureka.................. 9S/SfM5/4f 48 ' Fresno............... A 98/99-45/46 ..48 ` Independence.-... 98/99-40/41 43 Los Angeles......... 98/99-45/46 48 Needles................ 17/18--38/3S 22 Point Reyes........ 98/99-40/4] 43 Red Bluff..........A 98/99-33/34 (] 0 1(3 136 388 60C 609 513 361 162 37 1 ( : 1< 11 .348 58- 59: 49] 31? 130 23 ] ( . ( 1 4* 208 37! 39] Zh 175 "52 3 . c ( ( i 7: 271 48 49* 405 231 85 10 0 4; . 7( 24* 573 84] ill: 116] 97( 889 661 469 190 i ( ( 18 10{ 3& 401 26? 1& 47 7 0 2071 7241 ( ( ( 1 11? 30f 318 182 85 25 ] ( 3 ' 1 31 21( 51C 81( 879 71e 619 247 86 7 ( ( 12 128 41C 711 76? 615 390 154 36 1 ( . ( 11 m 38? 668 70< 579 367 145 31 1 281 281 274 344 411 518 541 478 504 ,44C 391 307 4758 C ( i 1\ 30S 565 57? 38C 289 152 52 4 2403 C 1 C 28 218 512 778 799 619 477 267 120 * 18 3834 C f 4c 110 225 272 235 212 15i 102 2] 1391 ( 6 (] If 217 41f 447 243 124 2f 3 0 '1495' 35C 33f 263 282 317 425 467 406 437 412 415 363 4474 Colo... 44/45-45/46 41 Sacramento.......... 98/99-45/46 48 Ran Diego ,. A 98/99-45/46 48 San Francisoo.... 98/99-45/46 48 San Jose............... 06/07-40/41 35 Denver................. 98/99-45/46 , 48' Durango............... 04/05-40/41 37 Conn.. D. C.. Fla.... Grand Junction.. 98/99-45/46 -.48. Leadville.............. 07/08-40/41 34 Pueblo..........:..A 98/99-45/46 .48 Hartford............A 04/05-45/46 42 New Haven.... A 98/99-45/46 48 Washington.......... 98/99-45/46 48 Apalachicola........ 13/14-45/46 33 Jacksonville......... 98/99-45/46 48 Key West............. 98/99-45/46 48. Miami.................. 11/12-45/46 35 Pensacola............. 13/14-45/46 33 Tampa...............A 98/99-45/46 48 98/99-45/46 Augusta................ 98/99-45/46 48 Macon................... 99/00-45/46 47 Savannah......... A 98/99-45/46 48 Thomasville 05/06-40/41 36 Idaho.. Boise.................. A 93/99-45/46 48 Lewistown........... 00/01-32/33 33 Pocatello............... 98/99-45/46 . 48 Ill........ Ind.... Chicago................ 98/99-45/46 Peoria................ A 05/06-45/46 Springfield........... 98/99-45/46 Evansville.........A 98/99-45/46 Fort Wayne___ A 11/12-45/46 Indianapolis. .-. 98/99-45/46 Royal Center___ 18/19-31/32 48 41 48 48 35 48 14 Terre Haute........ 12/13-45/46 Iowa .. Charles City........ >4/05-45/46 Davenport........... 98/99-45/46 Des Moines.......... >8/99-45/46 34 42 48 48 Dubuque............. 98/99-45/46 48 Keokuk................ >8/99-41/42 44 Sioux City........ A >8/99-45/46 48 Kan... Concordia............ >8/99-45/46 48 Dodge City___ A >8/99-45/46 48 lola........................ 05/06-40/41 36 Topeka................. >8/99-45/46 48 -Wichita.............. A >8/99-45/46 48 Ky.... Louisville............. >8/99-45/46 48 Lexington............. 98/99-40/41 43 Ia....... New Orleans....... 98/99-45/46 48 Shreveport........A >8/99-45/46 48 Me... Eastport............... 98/99-45/46 48 - Greenville............ >7/08-40/41 42/43-45/46 38 Portland........... A 98/99-45/46 48 Md... Baltimore............. 98/99-45/46 48 0 0 12 97 345 592 601 419 328 178 72 . 9 2653 2 1 15 98 332 582 595 405 326 202 101 21 2680 5 1 9 60 143 252 300 257 230 172 118 .49 1596 196 179 121 139 241 420 460 340 317 272 255 197 3137 . 21 21 52 151 329 512 527 383 339 249 167 72 8 8 126 411 710 1005 1023 897 790 616 275 64 5839 25 37 201 635 861 1204 1271 1002 859 1 1 59 347 743 1138 1218 883 071 377 152 23 280 332 509 841 1139 1413 1470 1285 1245 990 740 434 10678 . 3 4 91 377 730 1042 1042 875 724 446 195 : 29 5558 3 16 105 370 692 1065 1157 1062 859 524 213 47 6113 3 11 88 341 658 1017 1109 1023 840 522 221 47 5880 0 2 42 251 553 872 928 834 624 340 101 . 14 4561 0 0 1 23 154 300 323 252 159 38 2 0 1252 0 0 0 25 144 294 302 244 131 . 42 3 0 1185 0 0 0 0 2 14 .21 15 7 0 0 . 0 59 0 0 0 0 15 41 53 45 28 3 0 . 0 185 0 0 0 25 159 305 332 255 162 39 4 0 1281 0 0 0 6 60 149 157 126 62 11 0 0 571 0 0 0 0 4 85 312 529 533 448 274 107 13 5 91 322 532 538 449 278 108 14 1 . 2306 1 2338 0 0 1 45 206 390 395 332 194 `66 6 0 1635 0 0 2 48 208 361 359 299 178 52 5 1 1513 9 17 136 385 717 1025 1077 840 688 440 252 92 5678 5 9 107 378 688 932 992 779 603 371 193 52 5109 12 21 176 475 .821 1159 1224 1004 845 550 330 124 6741 6 7 88 337 .712 1116 1218 1080 861 531 259 67 6282 4 8 88 350 730 1126 1231 1035 790 436 178 28 6004 0 3 65 286 664 1056 1151 977 719 377 132 16 .5446 0 1 35 211 544 888 948 822 682 288 -85 , 6 *4410 6 13 106 374 737 1107 1211 1052 864 '504 217 41 6232 1 4 66 297 660 1032 1102 973 737 410 154 22 5458 n 16 116 373 740 1104 1239 976 860 502 245 54 6239 0 3 62 270 627 993 1072 897 687 358 133 15 5117 8 24 164 480 906 1362 1535 [281 995 552 255 62 7624 2 6 61 344 748 1176 1291 1111 835 448 171 29 6252 1 6 102 354 767 1204 1320 [132 843 446 171 29 6375 3 12 123 402 808 1249 1380 [190 915 493 204 41 6820 1 3 71 303 680 1077 1191 1025 761 397 136 . 18 5663 3 11 128 402 844 1273 1402 [206 909 485 202 40 6905 1 3 68 288 670 060 1144 954 712 365 142 18 5425 1 3 59 275 641 998 1046 868 668 351 139 20 5069 0 1 40 236 579 030 1026 817 599 282 98 8 4616 0 2 56 254 623 013 1096 917 659 326 116 13 5075 0 1 41 221 576 947 1016 836 604 290 103 9 4644 0 1 35 217 549 881 931 816 588 298 93 8 4417 1 3 48 258 601 916 964 862 650 352 123 14 4792 0 0 0 23 .145 304 323 247 129 31 1 0 1203 0 0 4 71 275 506 531 415 241 79 10 0 2132 158 146 271 628 827 224 1364 238 080 778 530 301 8445 69 113 315 643 1012 .464 1625 443 251 842 468 194 9439 28 48 182 466 794 182 1309 188 997 671 376 136 7377 0 1 33 227 526 855 921 837 637 343 95 12 4487 : * Computed from daily temperatures recorded by- United Statee Weather Bureau stations over a varied number erf seasons as indicated in the 3rd and 4th column of the table. Degree-day data for airport stations ue not included in this table. The data for United States cities were computed by .the United States Weather Bureau in 1946 and 1947 in accordance with the requirements of the National Joint Com mittee on Weather^Statistics. The data for a number of the cities listed are based on readings at more than one official city weather station during the periods of analysis, but the slight difference in the readings would not appreciably affect the resultant. " Letter A indicates city office and airport records combined. 430 CHAPTER 17 1952 Guide Table 2. Average Monthly and Yearly Degree-Days for Cities in the v-w ___n n i Kin* \ MTlM >:n I ' Statb Station Yeabs * L 1 a 5 0<c 0 5 >j< --> D < l >* J a a 03 <Ih fau S e. *< s D-j ----- -- Boston............... A 98/99-45/46 48 Fitchburg. 98/99-40/41 43 Nantucket. 98/99-45/46 48 Alpena___ Detroit.... 98/99-45/46 48 98/99-45/46 48 98/99-45/46 48 Grand Rapids.. 03/04-45/46 43 Houghton, i....... 00/01-40/41 42/43-45/46 45 Lansing-- Ludington. Marquette. 10/11-45/46 36 12/13-40/41 29 98/99-45/46 48 98/99-45/46 . 48 Duluth.......... Minneapolis. Morehead -- St. Paul........ 98/99-45/46 98/99-45/46 98/99-40/41 98/99-32/33 37/38-40/41 48 48 43 39 Miss... Mo.... Corinth---Meridian. Vicksburg.Columbia. Hannibal - 09/10-40/41 00/01-45/46 98/99-45/46 98/99-45/46 98/99-40/41 98/99-45/46 32 46 48, 48 43 48 Saint LouisSpringfield 98/99-45/46 48 98/99-45/46 48 09/10-45/46 37 Havre-- Helena... KalispeD. 98/99-45/46 48 98/99-45/46 48 99/00-45/46 47 98/99-45/46 48 Missoula.......... Drexel............. Lincoln........... North Platte.. 92/93-45/46 54 15/16-25/26 11 98/99-45/46 48 98/99-45/46 '48 Omaha............. Valentine........ Reno................ Tonopah___'. Winnemucca.. . 98/99-45/46 98/99-45/46 *. 05/06-45/46 14/15-40/41 98/99-45/46 48 48 41 27 48 N. H. N. J.. Concord..._ -- Atlantic City. Cape May....... Newark........... . 03/04-45/46 98/99-45/46 . 98/99-31/32 L98/99-23/24 35/36-40/41 43 48 34 32 N. M. Sandy Hook.. Trenton........... Albuquerque. Roswell......... . Santa Fe......... . 15/16-40/41 . 14/15--45/46 l 19/20-45/46 . 05/06-45/46 . 98/99-45/46 26 32 27 41 43 N. Y. Albany............ . 98/99-45/46 48 Binghamton.. . 98/99-45/46 48 4 98/99-45/46 48 N. C. Canton.......... . Ithaca.......- New York.... Oswego............ Rochester. - Syracuse........ Asheville......... Charlotte........ Hatteras......... Manteo............ Raleigh........... . 00/07-45/41 . 99/00-42/42 . 98/99-45/41 . 98/99-45/41 A. 98/99-45/46 A. 03/04-45/41 . 02/03-45/41 . 98/99-45/41 . 98/99-45/41 ; 04/05-28/21 . 98/99-45/41 40 44 48 48 48 43 44 48 48 25 48 Wilmington. .. ; 98/99-45/41 48 N. D. Bismarck........ . 98/99-45/41 48 Devils Lake... . 04/05-45/41 42 Grand Forks.. . 12/13-40/4 42/43-45/41 33 Ohio.. Williston.. Cincinnati Cleveland. Columbus.. Dayton.... . 98/99-45/4 . 98/99-45/4' . 98/99-45/4 . 98/99-45/4 . 11/12-42/L 45/46 48 48 48 48 33 Sandusky. . 98/99-45/4 ' 48 Toledo....... Okla.. . 98/99-45/4 ' 48 . 18/19-30/3 13 . 98/99-45/4 . 48 Ore... .. 98/99-45/4 > 48 A 11/12-40/4 1 45/46 31 7 15 98 3 12 29 144 4 15 15 87 3 53 79 235 5 7 15 111 3 54 84 256 5 8 20 128 4 647 1008 1108 inw 841 538 245 66 774 1139 1240 1137 940 572 254 70 690 904 1010 967 866 619 366 121 874 1238 1388 1321 162 764 448 168 749 1124 1134 927 566 253 56 927 1329 1382 219 808 477 170 764 1136 1143 944 569 263 57 5936 6743 5875 8278 6560 8777. 6702 70 94 268 5 18 36 167 4 41 55 182 4 86 99 258 91 110 285 e 80 97 292 t 8 23 167 4 20 47 240 1 965 1355 818 1190 794 1135 926 1306 965 1379 1066 1539 942 1415 1105 1609 1421 1251 820 474 195 1178 995 600 294 80 1183 056 698 418 153 1349 193 794 494 220 1470 i291 826 487 215 1497 1254 804 515 234 1372 1072 577 260 62 1555 1225 679 327 '98 9030 7149 7458 8745 9307 9723 7966 9327 11 24 169 4 0 . 1 13 006 005 0 3 62 1 3 66 0 2 51 0 1 38 1 2 48 14 31 223 27 54 275 43 66 291 66 102 332 . 7 20 188 37 56 275 4 6 95 1 5 85 4 9 131 1 4 84 S 19 167 . 8 18 140 7 105 10 23 188 18 49 189 1 2 39 1 2 38 942 1412 418 669 322 525 267 483 621 1000 652 1037 598 993 558 925 561 908 889 1215 1012 1376 944 1252 968 1235 918 1322 951 1235 788 1271 732 1144 799 1163 744 1169 877 1246 697 959 713 1010 801 1090 823 1228 546 867 527 852 1371 1078 573 258 60 7975 570 396 149 32 1 3087 440 274 107 17 1 2330 407 236 82 10 0 2069 916 655 337 120 14 5070 980 710 374 128 15 5393 909 651 322 108 12 4962 855 607 300 91 8 4596 827 596 302 109 12 4569 1102 923 555 315 106 7213 >1358 1102 614 341 133 8416 1157 990 639 413 192 7930 1135 956 630 413 220 8032 1267 997 545 275 81 7591 1072 903 590 369 179 7604 11096 843 493 219 38 6611 2 1056 792 407 166 25 5980 ' 1039 846 480 227 49 6384 >1088 810 410 157 24 6095 11166 962 563 287 74 7197 r 791 702 498 SOI 93 5621 5 87C 749 522 28(3 82 5812 i 884 768 536 321 114 v 6357 5 1213 993 637 m 100 7400 6 887 .750 485 m 37 5015 6 876 737 459 188 33 4870 1 6 65 635 3 1002 794 448 162 29 5500 1 2 40 579 6 m 833 49$ 201 31 5369 . 1 6 63 301 G04 957 0 0 27 258 646 913 0 0 26 191 512 781 12 15 129 451 772 1071 3 922 ; 748 441 154 25 5256 5 702 592 322 91 6 4517 3 585 ! 45$ 19$ SC 2 3578 4 89? ' 78f 544 291 6C 6123 4 li 117 411 753 1143 15 37 148 448 767 1137 15 .24 126 413 745 1110 1 1161 941 551 221 41 6 1155 95( 584 261 . 74 6 1165 995 661 341 9( 6648 6818 6925 27 61 219 550 898 1368 17 40 156 451 770 1129 6 1385 1131 695 34( 101 8305 6 4154 | 971 60< 292 Hi 6914 .1 4 50 272 594 940 8 952 771 465 172 3( 5280 2( X 147 440 762 1151 5 1188 1015 665 361 12* 7188 1( 26 132 423 751 1123 7 1155 96; 605 282 7: 6772 13 32 146 437 760 1147 >5 116 972 61 28< 7! 6899 2 0 3 49 279 565 800 7 71! 55! 315 11* 17 148 420 684 >0 601 4i: 19! 3! 15 4236 * 3224 0 0 0 1 7 m61 273 500 358 595 0 1 17 153 415 681 c ( 5 90 306 520 21 44 244 595 1057 1520 0 531 39 191 3* : 2 5* 461 24! 71 ' 2 6k 42$ 211 4 i 1 47 32< 14 2 4 147 118 642 34< 10 2554 3109 3275 2420 8937 42 76 295 687 1186 1676 190>66 16k 1312 752 41 141 10104 32 6C 274 663 1160 1681 15 160151291 711 35 ) 12: 9871 21 . 6 285 637 1104 1545 ; 53 273 611 960 u 93 354 684 1045 < 68 314 670 1019 3 151 122 67 18 89 ; 66 36 13 106 87 55 91 97 5 74 ) 43* 36 13 13 1 25 l 5 16.1 21> 9301 4990 6144 5506 i 71 309 660 992 i i 82 347 695 1067 > l l 100 370 718 1097 () () 28 169 513 805 ' ) 22 153 455 792 5-1 7 l 259 534 848 1161 79 93 J 75 l 41 > 16.l 2 l 55 106 i 86 l 53 ; 23 l 4 2 89 108 1 88 53 i 22 ' 4 1 il 64 i 50 i 21 2 6 . 5 46 68 > 45 ' 20 > 5 \ l 22 984 82 1 601 41 8 21 7 5412 6095 6269 3826 3670 7197 I 1 D 99 837 44 636 556 387 22a 7 4 4650 Estimating Fuel Consumption for Space Heating 431 Table 2. Average Monthly and.Yearly Degree-Days for Cities in the United States, Canada and Newfoundland* (Continued) State Station Years fOc. "< ocq 0aaZ $ *D-s d & < W m & Nov. fada Q z <"5 aw x < K0. *< SCS H> 3 *<3 s z <o -9 . Ore.... Portland............. 98/99-45/4f Roseburg./......... 98/99-45/41 Pa.... Erie....................... 98/99-45/46 Harrisburg........A 98/99-45/46 Philadelphia........ 98/99-45/41 Pittsburgh........... 98/99-45/41 Reading................ 12/13-45/41 Scranton............... 00/01-45/41 R. I... Block Island........ 98/99-45/41 Narragansett Pier 98/99-17/11 Providence...- 04/05-45/46 S. C... Charleston........... 98/99-45/46 Columbia............. 98/99-45/4( Due West......... 21/22-31/32 Greenville......... A 17/18-45/4( s. D... Huron................... 98/99-45/46 Pierre.................... 98/99-40/41 48 21 . 2* IOC 2T. 538 721 771 61C 532 36E 237 108 48 Z 2! 111 3H 54! 71- 73C 582 530 386 257 111 48 17 101 369 692 104$ 115$ 1101 922 591 284 68 48 . 1 6 . 67 314 637 990 1073 972 757 425 146 23 48 ( 2 3( 23! 54' 88- 962 881 681 371 115 17 48 ' : ; 61 322 651 982 1042 964 751 444 166 29 34 ; 5 61 30 60( 95: 1031 92$ 736 423 144 23 46 ( 22 n; 404 717 107* 1162 1071 862 523 213 48 1( . 11 71 3i; 591 911 1030 984 875 618 354 20 ] 2( 121 364 691 1012 m: 1074 916 622 342 113 42 1 16 101 351 661 102( lift 1027 847 538 237 48 ( ( ] 41 225 421 452 384 239 83 7 48 ( < 1 95 321 56( 561 482 305 126 18 11 ( ( $ 141 392 59* 651 491 411 158 29 c ] 12 121 41C 650 684 551 403 179 40 1 48 1C 2C 15$ 502 662 140$ 1572 1353 1039 573 271 70 4353 4332 6363 6412 4739 5430 5232 6218 5897 6397 6984 1866 2488 2890 3059 7940 42/43-45/46 Rapid City.......... 98/99-45/46 Tenn.. Chattanooga........ S8/99-45/4I Knoxville.......... A 98/99-45/46 Memphis........... A 98/99-45/46 Nashville......... 98/99-45/46 Texas . Abilene..............A 98/99-45/46 Amarillo............ A 98/99-45/46 Austin................A 26/27-45/46 Brownsville ... A 08/09-45/46 Corpus Christi... 98/99-45/46 Dallas............ A 13/14-45/46 Del Rio................ 05/06-45/46 El Paso..............A 98/99-45/46 Fort Worth....... A 98/99-45/46 Galveston............ 98/99-45/46 Houston.:........... 09/10-45/46 Palestine............... 98/99-45/46 Point Arthur....... 17/18-45/46 San Antonio__ A 98/99-45/46 Taylor............. ... 01/02-40/41 Utah.. Modena............... 00/01-45/46 Salt Lake City.. 98/99-45/46 Vt....... Burlington......... 06/07-45/46 Northfield ........ 98/99-42/43 Va....... Cape Henry...... 98/99-45/46 Lynchburg....... A 98/99-45/46 Norfolk................ 98/99-45/46 Richmond. ....... 98/99-45/46 Wytbeville ......... 02/03-40/41 Wash.. North Head."....... 02/03-45/46 Seattle ................ 98/99-45/46 Spokane............ A 98/99-45/46 Tacoma................ 98/99-45/46 Tatoosh Island... 98/99-45/46 Walla Walla. . 98/99-45/46 Yakima.............. 09/10-45/46 W. Va.. Elkins................ A 98/99-45/46 Parkersburg......... 98/99-45/46 Wis___ Green Bay........... 98/99-40/41 Ia Crosse .. . 98/99-45/46 Madison................ M/05-45/46 Milwaukee........... 98/99-45/46 Wausau................. 5/16-40/41 Wyo... Cheyenne..........A 98/99-45/46 Lander.................. 98/99-45/46 Yellowstone Park M/05-40/41 47 48 48 48 48 48 48 48 20 38 48 33 41 48 48 48 37 48 29 48 40 46 48 40 45 48 48 48 48 39 44 48 48 48 48 48 .37 48 48 48 48 42 48 26 48 48 37 4 11 136 438 887 1317 1460 1253 971 516 238 52 15 28 192 495 842 1178 1280 1140 981 598 339 C C 13 15C 432 691 711 604 412 185 39 (J l 2C 18$ 498 756 774 666 470 226 56 U 14 126 387 670 716 600 386 157 33 0 0 20 170 469 748 768 675 467 218 55 (1 . <i 10 96 332 602 619 483 296 110 23 1 2 42 221 548 854 861 719 546 284 107 0 2 31 227 410 458 315 185 46 5 0 0 0 8 65 176 191 111 65 11 1 0 0 0 11 102 255 282 204 93 17 1 0 0 0 6 70 293 574 600 437 281 91 15 0 0 2 35 203 413 413 262 139 31 3 0 0 6 88 366 615 615 432 291 104 14 0 0 5 79 285 553 586 463 270 97 16 0 0 0 14 123 290 334 255 130 27 0 0 1 27 160 331 361 247 150 36 2 0 0 4 67 261 496 512 401 236 60 11 0 0 0 0 1 1 27 177 328 375 254 151 31 171 366 390 287 148 37 37 2 4 0 0 2 56 234 462 494 375 214 64 6 11 156 499 m 1142 1190 944 816 567 338 3 5 98 371 712 1033 1093 871 716 446 236 23 51 209 530 870 1313 1467 1338 mi 694 339 106 62 1L2 283 602 947 1389 1524 1384 1176 754 405 0 0 7 125 398 676 731 682 526 301 86 1 2 37 230 521 799 829 732 537 287 81 0 0 9 129 392 668 712 650 483 254 62 0 1 27 196 486 780 814 722 538 278 72 7 13 82 352 662 916 945 836 677 410 168 251 229 255 350 491 642 697 597 610 505 428 67 69 170 365 554 704 759 637 595 436 299 160 20 71 37 184 480 817 061 1139 931 756 490 285 118 75 190 390 581 737 786 658 612 455 313 301 295 325 421 534 654 716 627 643 537 454 5 10 90 315 662 910 981 770 571 354 166 .8 17 124 395 778 050 1125 837 624 374 193 15 23 115 403 722 003 1033 947 763 489 229 1 . 3 56 286 617 930 977 882 660 369 129 17 38 179 494 889 329 1493 1329 1087 658 327 7 22 157 454 864 339 1492 1281 990 531 232 52 8 20 145 452 857 296 1451 246 1002 588 274 66 13 17 124 411 786 203 329 177 959 617 341 102 26 58 216 568 982 427 594 381 1147 680 315 40 46 251 587 876 144 1187 064 996 720 460 27 43 265 623 021 400 427 197 006 669 410 125 173 424 759 079 386 464 252 165 841 603 334 7197 3238 3658 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 5800 4928 7931 7421 7405 7079 8494 7536 8243 9605 Alta.. B. C.. Man.. N. B.. N. 8.. Ont... Calgary............. Edmonton........ Vancouver........ Victoria............. Prince Rupert. Churchill.......... Winnipeg.......... Moncton........... Saint John....... Halifax.............. Fort William___ Hamilton.......... London............. Ottawa.............. Toronto............. Windsor............. 1122 1426 1609 1355 1215 750 480 1224 1593 1810 1504 1299 777 428 657 818 893 736 682 498 326 462 738 815 689 651 504 366 702 893 933 804 809 645 521 1187 1773, 2356 2604 2288 2204 1530 1097 744 1302;1829 2111 1775 1631 822 397 595 936 1373 1528 1392 1190 798 474 870 1271 1417 1266 1132 792 505 783 1141 1280 1168 1065 768 493 1143 1596 1807 1582 1386 888 567 816 1178 1305 1187 1063 651 322 843 1200 1336 1240 1073 642 307 984 1494 1646 1459 1256 726 310 817 1155 1304 1206 1072 669 341 795 1172 1283 1148 995 582 251 9,650 10,285 5,573 5,485 7,063 17,148 10,980 8,812 8,678 7,614 10,496 7,119 7,425 8,816 7,374 .432 CHAPTER 17 1952 Guide Table 2. Average Monthly and Yearly Degree-Days for Cities' in the United States, Canada and Newfoundland* (Concluded) y l l a State Station P.E.I.. Y. T... b t a o Te S5 ZgYeabs . H O '* o^Q m 55 6 p < S' CO H O O o d u Q i -si 03 < s P3* 0* < N < s H B *->, Y 5* 57* 222 639 868 1246 1463 1338 1203 858 536 213 8,538 7* 20* 180 561 948 1407 1587 1392 1209 702 298 88 8,399 17* 43 276 661 1060 1534 1696 1481 1311 849 428 102 9,438 16* 68 396 781 1305 1767 2027 1635 1445 725 397 138 10,700 167 322 687 1209 1908 2440 2666 2159 1879 1092 580 246 15,356 Degree-days for cities in Canada and Newfoundland were supplied by. the Canadian Meteorological Division, Department 0/ 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 veiy 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 Wheat transfer surfaces Table 3. Correction Factors for Outside Design Temperatures* .Outside Design Temp F ..................................... -20 -10 0 +10 20 Correction Factor.............................. 0.778 0.875 1.000 1.167 1.400 %The multipliers in Table 3, which are high 1? nfild climates and low for cold regions, are not in error as might appear. The unit figures in Tables 4, 5, and 6 are per square foot of radiator or thousand Btu beat lpea per degree-day. For equivalent buildings and beating seasons, those in warm climates have lower design heat 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. Since the northern cities have more radiator surface per given building and a higher seasonal degree-day total than cities in the south, the total fuel per season will be larger for the northern city. Estimating Fuel Consumption for Space Heating 433 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. Estimating Gas Consumption . .. 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 rtable 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 i: 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, . ; : P = 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 in Table 3 as explained under Elstimating 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 firing, in a building located in Toledo, Ohio. The building has a calculated heat loss of 240,000 Btu per hr. The oil heat value is 144,000 Btu per gal, and the assumed seasonal efficiency is 80. The outside design temperature for Toledo is --10 F, and the inside design temperature is 70 F. ' Solution: From Table 5, under 80 percent efficiency and in the bottom line, the value of U is found to be 0.00383 gal per 1000 Btu hourly heat loss for 0 F out side temperature. The correction factor for --10 F outside design temperature ;434 CHAPTER 17 ...... 1952 Guide -from Table 3 is 0.875.. Solving 0.875 X 0.00383 0.00335. Making a further, cor- Tection 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 noraial 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 . 1 /' 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 (17) fob GasJ Based on 0 F Outside Temperature,, 70 F Inside Temperature , Hot Water -- Steak Warm Air! - Heating VaIjUE of Gas Btu fee . Cu Ft . Cu Ft Gas per Degree-Day . . per Sq Ft EDR, Up to 500 Sq Ft 500 to 1200 Sq Ft Over 1200 Sq Ft 500 535 : .800 . ` 1000 0.149 0.139 0.094 0.075 0.142 0.132 0.087 0.071 0.134 0,126 0.085 0.068 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 300 to Over ' ' .,.700 . . 700 Sq Ft Sq Ft Gravity . Fan . Systems 0.254 0.237 0.159 0.127 0.242, 0.226 0.151 0.121 0.231; 0.216 0.144 0.116 0.896 0.861 0.840 , 0.805 0.560 . ,0.538 0.449 0.431 1 Therm Gas Consumption, in Therms per Degree-Day . 100,000 ' Btu 0.000743 0.000709 0.000675 0.00127 0.00121 0.00116 0.00450 0.00430 ` * Abstracted from Comfort Heating, American Gas 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 normal 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 -totahwill 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 U is 0.875 X 0.0444 = 0.0389. From Table 2, D 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 during these three months the estimated consumption is '. . " 2953' . ' ~ X 58,100 - 27,600 lb. . Estimating Fuel Consumption for Space Heating 435 ---- , -----` ~ vyuoumrrxun- vunHTANTS \U) FOR UI Based on 0 F Outside Temperature, 70 F Inside Temperature . ' Unit Gal Oil per Sq Ft Steam Radiator Gal Oil per Sq Ft Hot Water Radiator Gal Oil per 1000 Btu per Hour Heat Loan Efficiency in Percent 70 ' 0.00105 ' 80 0.00092 0.00066 0.00058 ::! 0.00437 0.00383 - ?.n.L&fcracliau aSy peBrmirss^ionSiroim'0D'e0g^ree-D0a"y HWainthdObUoot k^(rSeedcoundcEtidoitnioonf, 1937). bv C Strock anrl C, tr n ' cPer 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 temperar 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 H X 24 X D 1000 (6> : F = pounds of, steam required for estimate period, . . .; H = calculated heat loss, Btu per (hour) (degree difference). 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 tikes caire,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 throughput the period, If ah average inside temperature other . . Table 6. .Unit Fuel Consumption* Constants (U) fob CokLb . 1 ' . ' Based oh 0 F Outside Temperature, 70 E Inside' Temperature- 40 50 Lb Coal per Sq Ft Steam Radiator.... 0.0216 0.0172 Lb Coal per Sq Ft Hot Water Radiator.. 0.0135 0.0108 - 60 0.0143 0.0091 - 70 SO i'. 0.0123. 0.0108 0.0078 0.0068 Lb Coal per 1000 Btu per Hour Heat Loss........................... 0.0889 0.0717 0.0592 0.0507 0.0444' VI AS|UW UkU UCI LPUlUlU* '' Abstracted by permission from Degree-Day Handbook (Second Edition 1937) bvC Strock&nHP W t> PTM* added for operation without night reductioS of temp^Vt^ C' ` B* 436 CHAPTER 17 1952 Guide Table 7. Steam Consumption op Buildings with Various Types of Occupancy* Type op Building No. Bldgs. Average Volume' Heated .Space . 1000 Cu Ft Steam fob Heating Lb per DD per 1000 Cu Ft Average Hours op Occupancy Office......... ............................ Office and Bank.................. Office and Printing.;......... Office and Theater.............. Office'and Stores or Shops. Bank............................ Department Store... Stores............... ,......... Loft.............................. Warehouse.................. Hotel and Club................. Apartment or Residence. Theater.............................. Garage........................ -- Manufacturing:.. i......... ; .. - Church.................. i........... Hospital....... ...................... School................................ . Municipal or Federal------ Lodge. Gym, Hall or Auditorium Miscellaneous.................. 334 49 8 7. 28 16 63 73 73 51 22 13 19 49 8 15 12 .7 2160 . 3000 4950 1615 3400 310 1795 1425 1240 1540 1350 1115 3215 0.685 0.577 1.230 0.412 . 0.617 0.786 0.385 0.624 0.588. 0.459 0.990 0.963 0.482 0.202 0.808 0.532 1.194 0.592 0.687 0.390; 0.479 12.1 13.1 17.7 12.9 . 13.2 11.7 11.1 . 10.4 10.0 9.4 22.3 21.8 12.9 7.9 22.0 11.5 15.6 12.4 21.4 Prinrir1** ** TT^ting, NfitinnaL Association of Building Owners and Manonert. . than approximately 70 F is to be used, the number of degree-days should be obtained for the new base. . :Example 7: An eight-stoiy 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 building heating? . Solution: Since the average inside temperature is approximately 70 F, the degree- days 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>368iooq lb of steam. F= 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 typ, 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 hot 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 building. Estimating Fuel Consumption for Space' Heating 437 Table 8. Heat Consumption Record fob Comparison Col. 1 Col. 2 Col. 3 Col. 4 Col. 5 Col. 6 Col. 7 ` Total Consumption Consumption For Heating Avg iuAAA Temp. ` 65 F Base Day Ls/Dbg Day/ , Mcuiy Sept.............. 337,500 170,600 T Oct................. 834,200 . 667,200 Nov............... 1,446,600 1,279,600 o . Ok Dec..........: 2,176.400 , 2,009,400 3 Jan............ 2,332,200 2,165,200 Feb....... : 2,131,100 1,964,100 Mar........... 2,021,900 1,854,900 2 Apr................ 1.241.500 1,074,500 May.............. 672,600 505,500 June.......... 258,600 91,600 July.......... 188,400 Aug........... 180,100 65 ; 146 : 1,170 0.575 53 . .339 1,966. .0.970 44 641 1,990 0.982 25 1,233 1,630 . 0.804 22 1,297 1,670 0.822 28 1,106 1,775 ' 0.888 ' 31 1,032 1,799 , - 0.885 43 ' 647/ 1,660 0.818 55 303 : 1,670 ; 0.822 / 50 1,830 0.905 Total....... 13,821,000 Sept.......... 330,200 Oct................. 887.100 Nov............... -1,525,200 A Dec............ 2,045,600 a ` Jan.........;. 1,933,400 Feb............ 1,990,200 Mar..........( 1,984,100 146,200 . 61 703,100 52 1,341,200 . 39 1,861,500 28 1,749,400 30 1,806,200 30 . 1,800,100 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 2J percent. 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 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 Table 9. Building Load Factors and Demands of Some Detroit Buildings . Building Classification Load Factor .. Printing..................'.................................................... Apartments.......................................................... . .. " Banin. Churches............ Theaters................. .'."..i... !. ............................................... 0.318 0.316 0.287 0.263 0.255 0.238 0.223 0.203 0.158 0.138 0.126 .Lb of Demand per (Hour) (Sq Ft of Equivalent Installed Radiator 8ubfacb) 0.184 0.207 0.217 0.209 0.225 0.182 0.248 0.152 . 0.145 438 CHAPTER 17 1952 Guide -The year under consideration may then be compared, month by month, with the previous year. Column 3, Consumptioii 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-rdays in 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. -. ;' MAXIMUM DEMANDS AND LOAD FACTORS : In. one form of district heating rates,!.a portion of the charge is based upon the maximum demand of the building. The maximum demand may be measured in several-different ways. It. may be. taken as the instantane ous peak or as the rate of use during any specified interval. One method is to take,the average of the three highest hours during the winter. These !figures.;are shown for a number of buildings- in Detroit in Table 9" . These maximum demands were measured by an attachment on the con densation meter, and therefore represent the amounts of condensation passed through the meter in the highest hours, rather than the-true rate.at which steam is supplied. There might be slight differences in these two quantities due to time lag and to storage of condensate an the system, but wherever this has been investigated it has been found to be negligible, ' 'The .load factor of a building is the ratio of the average load"-to the maximum load and is an index .of the utilization. Thus> in Table 9, the theaters, operating for short hours, have a load factor of 0.126 as compared with the figure of 0.318 for clubs and lodges. .. . REFERENCES . * Comfort Heating (American Gas Association, 1938). .. ` Are Automatic Air Shutters Justified on a Gas-Fired Conversion Burner? by W, M. Myler, Jr. and H, W. Nelson (A.S.H.V.E. Journal Section, Healing, Piping and Air Conditioning, Oct. 1948, p. 111). . . '` * Efficiency of Bituminous-Coal-Burning Space Heater, by J.'W. Tieman and F. L. Bagby (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning: Journal Section, Feb- 1951, p. -117). . . .. . . * 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). 5 The Stoker-Fired Warm-Air Furnace in the Research Residence, by S. Konzo (University. of Illinois, Engineering Experiment Station, Circular 39, 1939, p. 98). * Performance of a Hot Water Heating System in the I = B = R Research Home at the University, of Illinois (University of Illinois, Engineering Experiment Station, Bulletin No.. 349, Jan. 4, 1944). . .1 Fuels and Burners (Univesrity of Illinois, Small Homes Council, Circular G3.5, July 1949).. ,. . '. 8 Investigation 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. Transactions, Vol. 49, 1943, p. 345). 10 House Heating (Industrial Gas Series, American Gas Association, Third Edition). . .- 11 Report of Commercial Relations Committee (Proceedings, National District Heating Association, 1932). ,- u The Heat Requirements of Buildings, by J. H. Walker and G. H. Tuttle (A.S.H.V.E. Transactions, Vol. 41, 1935, p. 171). . CHAPTER 18 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 topi 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 waim-air furnace system, the size of the leader pipe to a given room depends upon the length of the leader and the tem perature of the warm air entering the room.at the register. For most successful operation, the furnace 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 have been expressed directly in terms of Btu per hour. 1 In general, it is advisable 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, and from this point there should be a uniform upgrade of at least I in. per foot of run. Leaders over 12 ft in length, of having a large num ber of elbow fittings should be avoided if possible. In cases where such leaders are necessary, it is recommehded 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 439 440 CHAPTER 18 1952 Guide in balancing the air distribution of the system, a damper should be placed in each leader pipe except one, this latter leader preferably being connected to a room heated at all times, such as a living room. In a gravity circulating system, the ratio of stack to leader area is quite p. IjSTFig. 1. A Sectional View op a Typical Plant Showing Good , * ", . Installation Practice* . A. ' House-chimney, no bends nor offsets. B. Top of chimney at least 2 ft above ridge of roof. C. `Flue lining' fireclay., D. :Ail-joints air tight. ' E. At least 8 in. brick. F. >No other connection beside that to furnace. G; Cleanout frame and door, airtight.. Hi' Smoke pipe, end flush with inner surface of flue. I. Draft door.' J. Use flue thimble. K. iCaaing body.. - ... ,, Li f~V>ring hood or bonnet, top.of all leader collars on M. Round leader,.pitch 1 in. per foot.. . - N. Sleeve with dead air space or 1 in. of non-: combustible insulation around leader where passing through wall. ' O. Dampers in all leaders, except one. . P. Transition fittingB. ' Q. Rectangular wall stack. -- R. Baseboard register. . S. Distributee pipes equally around bonnet. T. Floor register. . U. Return air face.^ _ V. Panning under joist. ,. W. Transition oollar. ;. X. Round return pipe. . - Y. Transition shoe. ... . Z. Top of shoe at casing not above pate level. From N.W.AM.&A.C.A.Manual 5: Gravity Code and Manual, Third Edition, 1947. important, although little is gained by providing wall stacks with areas . in excess of 75 percent of their connected leader pipe area. In most cases a 3J in: X 12 in. stack is the largest which can be installed in normal wall construction. Hence, any room having a heat loss much in excess of 9000 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 be, retained at the average value of 175. F, which has been recommended. . Gravity Warm Air Systems 441 Registers used for discharging warm air into rooms should have a net area not less than the area of the leader pipe to which the register is at . 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. Floor registers are easy to install, but they may interfere with' placement of carpets and may be dirt catchers. . 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 effectively receive 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. 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. Frictional resistance in the return air system is as detrimental as is resistance in the warm-air system, so that care should be exercised in locating return air grilles which require long return ducts. Where a divided system of two or more returns is used, the grilles must ' be placed to serve the maximum area of cold wall or windows. Thus, in rooms having only small windows the grilles can be brought as close to the furnace as possible, but if the room has large window exposure the grille should be located near the exposure. 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. . 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 ducts through which air is returned to the furnace 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 aft,er the duct has passed under some obstacle. Ducts returning air to the furnace should avoid heat sources which tend 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 in terposed between the heat source and the duct. The top of the return shoe should enter the casing below the level of the grate in the case of a coal furnace, and not more than 14 in. above the floor in the case of oil or gas furnaces. It may be wide to retain proper area. , 442 CHAPTER 18 . 1952 Guide OUTLINE OF DESIGN PROCEDURE The data underlying the design procedure are given in detail in a circular1 issued by the University of Illinois. In this procedure the design of the warm-air duct system is considered as an entire unit, sp that for a given heat loss, the sizes of leaders, stacks, boots, stackheads, and registers are 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, grilles, fittings, and registers are. designated as Combination Numbers. The numbers assigned and the combinations selected as standard are listed in the following Tables 1 to 4 inclusive.* . '. Table 1. First Stoby Wabm-Aik Ducts* ' Combination . :no. , Leadeb Pipe - Diameteb, In. Floor Register Size, In. ' Baseboard - ,. ' Size' . Extension i 8 .. 8 x 10 10 x 8 : 2M . - 2 .. 9 9 x 12 12 x 8 , 2M 3 10 10 x 12 12 x 9 3A ' 4 ' ' 12 ' 12 x 14 13x11 ' 5H 5 , 14 14 x 16 ' * 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 Stoby Warm-Aib Ducts--Single Wall Stacks and Fittings Combi nation No. Leadeb Pipe Diameter, In. SlACKb Size In. * ' Register Size, In. Baseboard - Sidewall . ' Size ' Extension ' ii 12 . 14 . ' 15 16 8 10 x 3M 9 12 x 3'H 10 14 x3M 12 12 x 5M 12 - 14 x5M 8 x 10 9 x 12 10 x 12 10 x 8 12 x 8 12 x 8 ' 12 x- 9 13 x 11. : 2M 2K ... 2H 3H 5M. 10x8 , 12 x,8 12 x 8 b Recommended stack sixes. Tables may also be applied to 3 in. and 3 1/2 in. stack depths. Table 3. Second Stoby Wabm-Aib Ducts--Double Wall Stacks and Fittings Combi nation No. Leadeb Pipe Diameteb, . In. Stack Size, In. Internal External Floor Register Size, In. ' Baseboard .Sidewall Size Extension 21 8 214 X 10 3H x 10% 8 x 10 ; 10 x 8 2>i 10 x 8 22 8 . 3 x 10 3% xlO% 8 x 10 10 x 8 2M 10 x 8 23' 9 2'A x 12 3^' x 12^ 9 x 12 12 x 8 2K 12 x 8 24 . 9 3 x 12 3Ys xl2% 9 x 12 12 x 8 21i 12 x 8 . c Commercial sixes vary 1/8 in. from values shown. r* i Gravity'Warm Air Systems 443 Table 4. Return Aik Ducts Combi nation NO. 31 . 32 . 33 34 35 36 37 38 Duct Dia. In. 10 12 14 16 18 20 22 24 Area at Shoe Con nection. Sq In. * Metal Grille Sizes ' ' Choose One .A B c When Joist Lining is Used* When Duct is Used No. of Joists Lined Minimum* Depth. la. Choose One 8x14 10x12 i 6x30 8x24 12x14 i .170 8x30 10x24 14x16 i 220 10x30 12x24 2 280 12x30 14x24 2 340 14x30 18x24 2 420 18x30 2 500 20x30 2 7 14 x 6 12 x 8 9 22 x 6 16 x 8 12 28 x 6 22 x 8 8 28 x 8 22 x 10 10 36 x 8 . 28 x 10 12.5 36x10 30 x 12 15.0 42x10 36x12 18.0 42x12 36x14 . d Based on 14 in. space between joists. ' * Use full depth of joist except when jpist depth is less than minimum depth required, taken pan must be used. . fG H . Fig. 2. Typical Warm Aik Boots I Table 5. Resistances op Warm Air Boot Combinations Expressed in Elbow Equivalents Warm Air Boot . A B C . d: E F G H I Name op Combination 45-Deg Angle Boot and 45-Dee Elbow 90-Deg Angle Boot Universal Boot and 90-Deg Elbow End Boot Offset Boot 45-Deg Angle . Floor Register--Second Story Offset Offset ' Equivalent No. op 90-Dbg Elbows i .i i 2 214 A 3 3 2 Cl* 444 ' CHAPTER 18 /v . , . 1952 Guide * e'air spoco- open. Insulated with Space or cow ered with magne sia, osbestos, or sand. Inner tmer-from top cosing ring to grate /eve l , /feta/ casing Fig..3. ^Details of Foenace Bonnet, Casino, and Foundation . (From N.W.A.H. & A.C.A. Manual 5, Third Edition) 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 that free areas be maintained throughout fittings. . Figs.-3 and 4 show recommended practice as given by the N.W.A.H. & A.C.A. For construction, design features, and ratings of gravity furnaces see Chapter 15. Carrying Capacity The Btu carrying capacities of the selected warm air and return air combinations are shown in Tables 6, 7 and 8. . The selected types of return air ducts and fittings are shown in Fig. 5. . Support tojo/5t or ceiln-- ' Masonry wall, /feta! th/mbto. Collar Sonnet PUjoints toped with \ asbestos paper \'r'r/inght collar Insulated with s layers of air ceell/loassbbeessttbo:s paper whenp/pe passes thru unheaied space. Fig* 4. Details of Bonnet and Leader of Gravity Warm-Air Furnace ' .. (From N.W.A.H. & A.C.A. Manual 5, Third Edition) . Gravity-Warm Air Systems 445 Table .6. Warm Air Carrying Capacity, Btu Delivered, First Story Registers* v. v. Length of Leader Pipe--in Feet , Combi- . NATION No. No. OF Elbows 4 Ft 6 Ft 8 Ft 10 Ft 12 Ft 14 Ft 16 Ft 18 Ft 20 Ft 22 Ft 24 Ft 1 6,020 5,850 5.680 5,510 5,340 5,170 5,000 4.830 4,660 4,490 4,320 2. 7,620 7.400 >.180 6,970 6,760 6,540 6,320 6,110 5.890 5,680 5,460 3 1 9,400 9,140 8,870 8,600 8,340 8.070 7,810 7,540 7,270 7,010 6,740 -4 : 13,350 12,970 12,590 12.210 11,830 11,450 11,080 10,700 10,320 9,950 9,560 5: 17,520 17,020 16,530 16,040 15,550 15.050 14,550 14.050 13,560 13,060 12.560 ' :l 5,850 5,660 5,490 5,330 5,160 5,000 4.840 4,670 4,510 4,340 . 4;i$o 21 7,360 7,150 6.940 6.730 6,520 6,320 6.110 5,910 5,700 51500 5,290 3 2 9.090 8,840 8,580 8.320 8.060 7.800 7,550 7,290 7.040 6,780 6,520 4 12.910 12,540 12,170 11,800 11,430 11,060 10,690 10.320 9.950 9,580 -^,210 5 16,940 16,450 15,990 15,500 15,040 14,550 14,080 13,600 13,120 12,650 12,150 1 2 .3 4 5 5,620 5,460 5,310 5,150 4,990 4,830 4,670 4,510 4,350 4,190 4,030 7,120 6.910 6,710 6.510 6.310 6,110 5.900 5,700 5,500 5,300 5,100 3 8.780 8,530 8.280 8,030 7,780 7,530 7,290 7,040 6.800 6,550 6.300 12,450 12,100 11,750 11.400 11.050 10.700 10,350 10,000 9,650 9,300 8,950 16,360 15,900 15.440 14,970 14.510 14,050 13,600 13,130 12,660 12,200 11,750 1 5,420 5,260 5,110 4,960 4.800 4,650 4,500 4,350 4,190 4,040 3,890 2 6,860 6,660 6,460 6,270 6.080 5,890 5,690 5,500 5,300 5,110 4.910 3 4 8,460 8.200 7,980 7,740 7,500 7,260 7.020 6,780 6,550 6,310 6.070 4 12,010 11,670 11,330 10390 10,650 10,310 9,970 9.630 9.290 8,950 8.610 5 15,770 15,320 14,880 14,420 13,990 13,540 13,100 12,650 12,200 11,750 11,310 1 2 '3 4 5 5,240 5,090 J 4.940 4,790 4,640 4,500 4,350 4,200 4.050 3.910 3,760 6,630 6,440 6,250 6,060 5.880 5,690 5,500 5.320 5,130 4,940 4,750 5 8,180 7,950 7,720 7,490 7,260 7,030 6.800 6,560 6.330 6,100 5,860 11,610 11.290 10,950 10,620 10,300 9,070 9,640 9,320 8,990 8.660 8.320 15,250 14,800 14,380 13,950 13.520 13,090 12,650 12,230 11,800 11,370 10,940 'Additional values for 6 and 7 elbows are given in Manual 6, N.W.AM.A.C.A. . :. Table 7. Warm Air Carrying Capacity, Btu Deuvered Second Story Registers*' Length of Leader Pipe--in Feet Combi nation No. *>. NO. OF Elbows 4 Ft 6 Ft 8 Ft 10 Ft 12 Ft 14 Ft 16 Ft 18 Ft 20 Ft 22 Ft 24 Ft 11-22 - 8,370 8.140 7,900 7,670 7,430 7,190 6.950 6.710 6.470 6,240 6,000 12-24 10,040 9,760 9.470 9,190 8,900 8,620 8,330 8,050 7,770 7,480 7,200 14 1 11,710 11,380 11,050 10,720 10,390 10,060 9,720 9,390 9,060 8,730 8.400 15 . 16,200 15,750 15,300 14.840 14.380 13,920 13,460 13,000 12.550 12,100 11,640 .. 16 18,920 18,390 17,850 17,310 16.780 16,240 15,710 15,180 14,640 14,100 13,570 11-22 12-24 ' 14 . 15 16 7,940 7,720 7.500 7.280 7,050 6,830 6,600 6.370 6,150 5,930 5,700 9.540 9,270 9.000 8.730 8,460 8.190 7,920 7,650 7,380 7,110 6,840 2 11,120 10,810 10,500 10,180 9,870 9.550 9,230 8,920 8,610 8,290 7,980 15.400 14,970 14,530 14,100 13.670 13,230 12.800 12,360 11.930 11,500 11,070 17,980 17,470 16.960 16,450 15.950 15.430 14,830 14.420 13,910 13,400 12,890 11-22 12-24 14 15 16 7,530 7,320 7.110 6,900 6,680 6,470 6.250 6,040 5,830 5,620 5.400 9,030 8,780 8.520 8,270 8,010 7,750 7,500 7^240 6,990 6,730 6,470 3 10,530 10,240 9,940 9,650 9.350 9,050 8,750 8.450 8,160 7,860 7,560 14,580 14,180 13.780 13,370 12,950 12,530 12,120 11,710 11,300 10,890 10.480 17,040 16,550 16.070 15,580 15,110 14,620 14,140 13,660 13.180 12,700 12,210 11-22 12^24 14 15 16 7.120 6.920 6,720 6.520 6,310 6.110 5,900 5.700 5,500 5,300 5.100 8,530 8,290 8,050 7,810 7.570 7.330 7,080 6.840 6,600 6,360 6,120 4 9,950 9,670 9,390 9.110 8,830 8,550 8.260 7.980 7,700 7.420 7,140 13,780 13.390 13,000 12,610 12.220 11,830 11,440 11,050 10,670 10,280 9.890 16,080 15,620 15,170 14,710 14,260 13.810 13,350 12,900 12,440 11,980 11,530 11-22 6,700 6,510 6,320 6.130 5,940 5.750 5,560 5,370 5.180 4.990 4,800' 12-24 8.040 7,810 7.580 7.350 7.130 6,900 6,670 6,440 6,220 5,990 5.760 14 5 9.370 9,110 8,850 8,580 8,310 8,050 7,780 7,510 7,250 6,980 6.720 15 . 12,970 12,600 12.240 11,870 11.500 11.140 10,770 10,400 10,040 9,680 9,310 16 15.140 14.710 14,280 13,850 13,420 13,000 12,570 12.140 11,710 11,280 10,850 * When floor registers are used, see Fig. 2. b No. 21 for Btu values multiply 11-22 values by 0.83. 0 No. 23 for Btu values multiply 12-24 values by 0.83. 446 CHAPTER 18 1952 Guide - Table 8. Return Air--Carrying Capacity--Btu Serviced Return Air Com bination No. Duct Dia In. Type A. Btu per Hr Types B * and C Btu' per Hr Type D Btu per Hr . Type E Btu-per Hr Type F Btu per Hr . Return Air Com* BINATION No. 3132 33 34 35 36 37 38 10 11,300 9,500 7,800 12 16,300 13,700 : 11,300 5,000 7,200 7,800 11,300 31 32 14 22,200 18,700 15,300 9,800 15,300 ' 33 16 29,000 24,400 20,000 12,800 20,000 34 18 36,700 30,800 25,300 16,200 25,300 20 45,300 38,000 31,300 20,000 31,300 35 36 22 54,800 46,000 37,800 24,100 37,800 24 65,200 ,54,800 45,000 28,700 45,000 37 38 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, 10 and 11. 2. Prepare a layout showing (e) furnace, (6) 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 the room to be heated is on first or second story; (6) the approximate length of leader pipe in 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. Up to 20' Same as Type E except that col* tar and.shoe are same as for Type A. * Type F Note: For Types C, D, E, and F return-air duct 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 of Return-Air Duct Systems ^Gravity. Warm Air Systems 447 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,thecom- bination 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, reid directly in Tables 1, 2, or 3 the leader, stack, and register sizes required. . .. .. . 6. From Table 8 select the combination number for the return-air system to cor respond with the Btu serviced and the type of return-air system. Then from Table 4 select the duct!and grille sizes, etc., corresponding to the same combination hiun- ber. ' '' ; '. . 7. Select a furnace having a register delivery, in Btu per hour, equal to the total heat loss from the structure. Standard work sheets to facilitate design according to the above recom mended procedure, are available from N.WA.H. & A.C.A. Fia. 6. Typical Basement Line Drawing Design Examples Examples 1 and 2 will illustrate the use of the tables in selecting warm-air and return-air system sizes. - . Example 1: For a room which has a heat loss of 22,500 Btu per hr, select the size 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 14 in. floor register or a 13 X 11 in. baseboard register with a 5} in. extension. Example S: What is the size of a return-air system of Type D which is to serv ice 35,000 Btu per hr? . . Solution: From Table 8 find Combination Number 37 which will service 37,800 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 duct42 X 10 in. or 36 X 12 in. If joist lining is UBed the minimum depth should be 15 in. for two 2-joist Bpaces 14 in. wide, or 10 in. for three joist spaces. . 448 CHAPTER 18 1952 Guide REFERENCES \ ........ `The engineering data were obtained from University of Illinois, Engineering EzperimentStationBulleliris Nos.141,188,189 and 246; Warm Air Furnaces and Heat ing,Systems; by A:: C,1 Willard, A. P. Kratz, V.S. Day',"and S; Konzo. See also Manual :5: Gravity Code, and Manual for the Design and Installation ^of Gravity Warm Air Heating Systemsj Third Edition, 1947, published by. the NationalWarm AirHedtihg and Air Conditioning Association. -. . * Simplified Procedure for Selecting Capacities of Duct Systems for Gravity Warm Air Heating Plants,:by A.P. Kratz and S. Konzo {University of Illinois','Engineering Experiment Station CfircularA5, Dec.,,1942). . := , _ . . GwitylCpde and Manual for the Design and Installation of. Gravity Warm Air Heating Systems,' Manual 5, Third Edition. 1947, National Warm Air Heating and Air Conditioning Association. .. CHAPTER 19 FORGED WARM AIR SYSTEMS Air Distribution, Standard Combinations of Parts, Simplified Method 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 circulations 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'i 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 S in such a way as to give a greater uniformity of temperature distribution. . ,!. 4. Humidity control is more readily attained. - ;v 5. The air may be cleaned by sprays or filters, or both. .. ;J ,, 6. The fan and duct equipment may be utilized for a complete-cooling and de-; humidifying 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, therebyincreasing 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. 8. 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 15 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 grilles. . In general it has been found that changes in the type, air velocity, and 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 warm 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 wall, and the return openings near the greatest outside exposure. In any case, the warm air registers should be located so that the air stream never discharges directly against people at rest. - Tests' in Warm Air Research Residence No. 1 at the University of Illinois, have indicated that continu ous blower operation gave better results than intermittent operation. 449 450 CHAPTER 19 1952 Guide 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 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 fpm, should be avoided as they may cause drafts. High side wall registers must be of such type that 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 Fig. 1. Recommended Type of Base Board and Low Sidewall Registers* Sidewall Registers6' * Vertical bare with adjustable 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 registers should not exceed 22 deg. For baseboard locations, the. deflection for horizontal, multiple valve registers should not exceed about 10 deg. 6 Horizontal valves, in back or front, to give downward deflections not to exceed from 15 to 22 deg. 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 air 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 B of Manual 7 of the National Warm Air Heating 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 and 2 have been recommended as standard by the National Warm Air Heating 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. Forced Warm Air Systems 451 Table 1. Warm Air Duct System Combinations of Parts ' Selected as Standard Con BINA* TION NO. Stack Size In. Branch Pipe - Size, In. Round Rec tangular Registeb Size, In. (See Figs. 1 and 2) Babe^boabd High ob Low Sidewall Floob .Registers* 1 2 3. 4 5 6 41 10 x 3i 6 4x8 10 x 6 8 x 10* 42 ' 10 x 3} 6 4x8 10 x 6 8 x 10* 43 12 x 31 7 . 5x8 . 12 x 6 9 x 12* 44 14 x 31 8 6x8 14 x 6 . 9 x 12* or longer 45 10x3} 9 8x8 (2) 10 x 6 10 x 12* (2-Stacks) or (1) 24 x 6 46 12 x 3} 10 10 x 8 (2) 12 x 6 12x14* (2-Stacks) or (1) 30 x 6 Requibed Increase in "Width op .Tbunk Duct, In. 7. i 2 3 4 5 7 * Use these items only when the building construction or capacity requirements necessitate the use of floor registers. The sizes listed for floor registers correspond to the standard sizes for gravity warm air furnace . systems, except for the sizes of the floor box 'collars. The use of standard blind boxes is suggested. ' A 12 x 5J in. stack may be used on Combination 45, and a 14 x 5i in. stack on Combination 46 with floor registers. .... Dampers Suitable dampers for air direction or volume control are essential to any duct system. Special care must be used, in the design of any system, to avoid turbulence and 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 provided for each main or duct branch. Labels placed on ducts should indicate 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 radii of elbows should preferably be not less than one and one-half times the pipe diameter for round pipes, or the equivalent round pipe, size in the case of rectangular ducts. Warm air ducts passing through cold spaces,' or where 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. , 452 CHAPTER 19 1952 Guide: /- - Table 2. Return Air Duct System Combination of Parts Selected as Standard Combi nation No. Return-Aih Intake , Size, In. BaseBoabd Floor* Riser Size, In. Where - Stack is Used in Stud Space . Branch Pipe Size; In: Round Rectan gular Required When Joist Lining Increase in IS U8BDb . - Width op Number op Joist , Trunk Duct Spaces Lined and (por 8 In. Minimum Depth op Space Required Depth op Duct), In. i 2 3 4 66 7 '8 51 10 x 6 6 x 10 10 x 3i . or 4 x 14 6 4x8 a space of 3 in. depth i 52 10 x 6 6 x 10 10 x 3I or 4 x 14 6 4x8 1 space of 3 in. depth 2 53 12 x 6 6 x 12 12 x 31d : 7 5x8 1 space of 4 in. or depth . 6 x 14 3 54 14 x 6 6.x 14 14 x 3id 8. ,6x8 1 space of 5 in. depth 4 55 24 x 6 6 x 30 Two 9 8x8 1 space of 6 in. or stacks depth or 2 spaces 30x6 each. of 3 in. depth 10 x 3J. 5 56 30 x 6 6 x 30 Two 10 10 x 8 1 space of 7 in. stacks depth or 2 spaces 12 x 3id of 4 in. depth 7 : 57 8x30 12 15x8 1 space of 9 in. 12 depth or 2 spaces of 5 in. depth. a Use these items only when building construction^ or capacities, require the use of floor-intakes.. The sizes listed correspond to standard sizes for gravity installations, except floor box collars. The use of standard blind boxes is suggested. , . -. .; ;"' b Based on 14 in. space between joists*. .Use full depth of joist, except when joist depth*is* leg? thuyt mini mum depth required, in which case a drop pan must be used. This may occur when two or more return ducts are connected to the same joist space. . . -v , / 0 If it is desired to use 14 in. x 3| in. stud space, it makes no difference whether this space has protruding' keys or:not. r. - . = >` .i, . 4.If it is desired to use 14 in. x 3| in. stud space, the plaster base must be smooth, without any protruding plaster keys to interfere with the flow of air. .' STANDARD COMBINATIONS OF PARTS The combinations of parts selected as standard by the National Warm. Air Heating arid Air Conditionirig Association are shown in Tables 1 and 2. A method for selecting these combinations is indicated in the following section Simplified Method of Design. ' SIMPLIFIED METHOD OF DESIGN A simplified method for selecting the combinations of branches, boots, stacks, and registers, is given3 in Manual 7 of the National Warm Air Heating and Air Conditioning Association. In this method, the sizes of the branch ducts are obtained from two tables giving their Btu capacities. The proper combination of parts for each branch can be determined if the follow ing information is available.' ' : a. Location of room, that is, whether on first or second story. Forced Warm Air Systems 453 6. Actual length of duct from bonnet to boot; in feet. c. Btu loss from room to be heated. . d. Equivalent lengths in feet of all fittings and of the register. Fig. 3 shows .the values of equivalent lengths of fittings commonly used for domestic systems. This simplified method is applicable to structures having heat losses not in excess of approximately 120,000 Btu per hour. The capacities shown in Tables 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 100 deg temperature rise of the air, and a static pressure available for overcoming friction losses in the external duct 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 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 in column 7 of Table 1, or column 8 of Table 2. DESIGN PROCEDURE FOR LARGE SYSTEMS4 ' For buildings having a heat loss in excess of 120,000 Btu per horn1, the design procedure6 given in Manual 9 of the N.W.A.H. & A.C.A., may be used, except where ventilation air volume exceeds volume required to sup ply calculated heat loss. This procedure consists of: 1. Calculation of design heat losses from individual spaces in the structure. (See Chapter 11.) .. 2. Location of registers and return intakes on floor plan, showing types of registers, with distance from register to opposite wall and deflection of registers desired. . 3. Laying out a proposed duct system for both warm air and return air sides of the system, and including details of types of fittings and the actual and equivalent lengths of each branch line from. bonnet to register, without sizes. (See Fig. 3, Groups 1 through 6, for equivalent length of fittings.) . , . 4. Determination of bonnet temperature. If. rating sheet for furnace-blower unit specifies a fixed value of bonnet temperature, enter table at this value. If not specified, use the following procedure: Use Table 5 for buildings having a heat loss between 120,000 and 350,000 Btu per hr or Table 6 for buildings having a heat loss greater than 350,000 Btu per hr. Select shortest actual length and read downward in nearest column in Tables 5 or 6 until lower heavy diago nal line is reached, but do not cross line. Run horizontally to first column of table and note bonnet temperature. Also select longest actual length and read downward in nearest column in Tables 5 or 6, until upper heavy diagonal line is just crossed. 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. 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 of duct system. A. Warm air branches. a. Use Table 9 to select maximum bonnet pressure usually required for the trunk carrying the maximum volume of air (cfm). If the maximum 454 CHAPTER 19 1952 Guide ~ Table 3. Capacity Tables fob Warm Aik and Return Air Branches*' b FIRST STORY For UNINSUL- Mettal Ducts Actual Length (from Bonnet to Boot) or, (from Return *lenum to Boot) in Feet ' ' 1 to 7 FT. 8 to 12 13 to 17 18 to 24 25 to 34 35 to 44 45 to 54 FT. FT. FT. FT. FT. FT. Col. a Col. b Col. c Col. d Col. e Col. f Col. g Warm Air Combi- NATION No. Air . Combi- nation No. Section A. 7200 12500 40 to 69 16000 Equivalent. 19100. Ft for Fit tings and ' 25000 Register 32000 80000 6700 11700 15000 18000 6100 10800 14000 17000 23400. 21600 30000 28000 75000 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. 4600 8500 100 to 129 11300 Equivalent 14300 Feet 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 ' 4100 7300 9800 12300 14600 .19600 49200 3800 6900 9100 11700 13800 18200 45800 3600 6400 8600 11000 12800 17200 41900 3400 6000 8100 10300 12000 16200 40300 2900 5300 7200 9100 10600 14400 36000 2600 4700 6400 8100 9600 12800 31800 2300 4200 5600 7100 8400 11200 28100 41 42 43 44 .45* 46* ;-- " 51 52 53 54 55 56 $7* Section E. 165 to 200 Equivalent Feet ,' 3800 6500 8800 11000 13000 17600 44100 3500 6100 8200 10500 12200 16400 41500 3300 5700 7700 9900 3100 5400 7200 9300 11400 10800 15400 14400 38800 ,36000 2700 4800 .6400 8300 9600 12800 32000 2400 4300 5700 7300 8600 11400 28200 2100 3800 5000 6400 7600 10000 24700 41 42 43 44 45* 46* -- 51 52 53 54 55 56 57* Fob INSULATED Ductb Col. a 1 TO 9 Col. b 10 TO Col. c . Col. d 18 TO 24 FT. 25 to Col. e 35 to ' For Ducts that are COM PLETELY INSULATED with i In. Thick Insul ation from Bonnet to Boot, use these Column Headings. * These tables are for use in 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 tables. c Use these, items only when the building construction, or capacity requirements, necessitate the use of two adjoining stacks or floor registers. Forced Warm Air Systems . . 455 Table 4. Capacity Tables for Warm Air and Return Air Branches** *> SECOND STORY For UNINSU LATED Metal Ducts Actual Length (from Bonnet to Boot) or, (from Return Plenum to Boot) in Feet 1 to 7 8 to 12 13 to 17 18 TO 24 25 to 34 35 to 44 45 to 54 FT. - ' FT. FT. FT. FT. , FT. FT. Col. a Col. b Col. c Col. d Col. e Col. f Col. a WXrm Air . Combi. NATION No. Return Air Combi- nation No. Section A. 40 to 69 Equivalent Ft for Fittings and Register 6300 10900 14000 17000 21800 28000 70000 5700 10000 13000 15900 20000 26000 65000 5200 9200 12100 14900 18400 24200 60500 4800 8500 11400 13900 17000 22400 57000 4100 7300 10000 12400 14600 20000 50000 3500 6400 8800 11100 12800 17600 44000 3100 5600 7800 9900 11200 15600 39000 41 51 42 '52 43 53 44 54 45* . 55 46' 56 57' Section B. 70 to 99 Equivalent Feet 5000 .9000 11900 14800 18000 23900 59500 . 4600 8200 11000 13900 16400 22000 55000 4300 7600 10300 13000 4000 7100 9600 12200 15200, 14200 20600 19200 51500 48000 3400 6200 8400 10800 12400 16800 42000 3000 5400 7500 9600 10800 15000 37500 2700' 4700 6700 8500 9400 13400 33500 -41 51 ' 42 52 43 53 44 54 45' 55 46' 56 -- ; - 57' Section C. . 4200 7700 100 to 129 10400 Equivalent 13000 . Feet 15400 21700 52200 390) 7200 9700 12100 14400 19400 48400 3700 6700 9000 11300 13400 18000 45300 3500 6200 8400 10600 12400 16800 42300 3000 5400 7400 9400 2600, 4700 6500 8300 10800 9400 14800 13000 37000. 32500 2400 4100 5800 7400 8200 11600 29000 41 42 4344 45" 46' -- 51 52 53 54 55 56 57' Section D. 130 to 164 Equivalent Feet 3800 6800 9100 11400 13600 18200 45500 3500 6300 8400 10500 3200 5800 7900 9800 12600- 11600 16800 15800 42000 39600 3000 5500 7400 9200 11000 14800 36800 2700 2300 4800. 4200 6300 5700 8100 7200 9600 8400 12600 11400 32200 28200 2100 3700 5000 6400 7400 10800 25100 41 42 43 -44 45* 46' --* ' 51 52 53 54 55 56 57' Section E. 165 to 200 Equivalent Feet 3500 6100 8200 10300 12200 16400 41000 3200 5700 7600 9500 11400 15200 38300 2900 5300 7100 8900 10600 14200 35800 2700 5000 6700 8300 10000 13400 33400 2500 4400 5700 7400 8800 11400 29000 2100 3900 5100 6500 7800 10200 25800 1900 3400 4500 5800 6800 9000 22800 41 42 . 43 44 45' 46' -- 51 52 53 54 . 55 56 57' ' Fob INSULATED Ducts Col. a 1 to 8 FT. Col. b- 9 to 14 FT. Col. c 15 to 20 FT. Col. d - Col. e 21 to 27 28 to 42 FT. Col. f 43 to 54 FT. For Ducts that *bb COM PLETELY INSULATED with | In. Thick Insulation from Bonnet to Boot Use these Column Headings. * These tables are for use in sizing both the warm air and the return air branches. b Frictional resistance and temperature drops in ducts have both been accounted for in these tables. c Use these items only when the building construction, or capacity requirements, necessitate the use of two adjoining stacks or floor registers. ' .. 456 CHAPTER 19 / Fig.. 3. Equivalent Length of Fittings GROUP 1. WARM AIR AND RETURN AIR BONNET OR PLENUM. 1952.Guide ggOUP^; ANGLES AND ELBOWS FOR TRUNK DUCTS, inside OACmjs % width OF OUCT. *-"'* to. ft 4 TO IS - S* < TO 27- IO' 2t TO 4t- IS* 42 TO S2-20' S3 TO 64* 25 CQ. rt 4 TO ll-IO* 12 TO 21-19* 22 TO-27-20' 29 TO 33 - 29* 34TO 42 - 30* 43TO SI- 40` . 92 TO 64--SO* 'V > V 5* CO FT. rx , ^ 4 TO 6 - 20*-w T TO 0 40* 12 TO IS 95* 16 TO 21 74* 22 TO 27-0*' 26 TO33-129* 34 TO 42-190* * TO II - IS' * 12 TO 21 - 20* 22 TO 27- 29' 26 TO 42 - 40* Vt'`' ` ' Forced Warm Air Systems .. Fig. 3. Equivalent Length of Fittings (Continued) GROUP a: boot fittings. - FROM BRANCH to stack; 457 30'cart 35`to. rx , Wan 4Vu.it 70'to. rt 30'to. n Wn. rx Wuft 15`ta. rt . SS'urt GROUP 5. STACK ANGLES, ELBOWS. AND COMBINATIONS . 5'u ft . 10'u n GROUP 6. RETURN.AIR ten 'toxsk-ss* 12 X SU 65. MX3I-.T0 mt k X 3 . 7V* 12 X 3 g - 63* I4X3V-90* 10'n rt - 65*66 rt bonnet pressure is not high enough to accommodate the pressure loss through the registers, use a higher bonnet pressure. If the register presure 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 register pressure loss from maxi mum bonnet pressure. so* urt `' ft.A, emu. AND ritTWC. R.A. GAtU. TO STUD SPACE. R.A. CAILL ONLY. FLOOR GAtU. TO LIMCR 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. 1, Chapter 31), volume (cfm), and pressure drop per 100 ft of duct. .. ' B. Return air branches. : a. Select a low value of actual duct loss obtained from step b under item A for the suction loss of return duct system. '468 * CHAPTER 19 f' ' 1952 Guide ' - Fig. 3. Equivalent Length of Fittings (Concluded) CROUP 7. REGISTERS (iNCUUOINC LOSSES IN STACKHEAD AND VO-OCITY PRESSURE). PT 25 EQ. FT. FL.REC. i. BOX ONLY Table 4A. Equivalent Length fob Registebs Deflection Angle A r Baseboard, High ' or - Low Sidewall Registers .' Floor Registers with Box only Eq. Ft. 35 For 2-way deflection registers, add the vertical and horizontal deflection angles together and multiply by 0.7. Select closest angle A in Table 4A. b. Proceed in sizing return air branches by the same method described for . the warm air branches. ' . C. Trunk duels for warm air and return air sides of system. 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. . c. Determine trunk duct size by using an air friction chart, volume (cfm), - and pressure drop per 100 ft of trunk duct. . - -. 8. Selection of Blower. . A. Determine total cfm air delivery (the sum of all branch cfm values). B. Determine static pressure requirement. ' a. For furnace-blower combination units it is the sum of bonnet pressure and suction pressure. b.' For blowers separately selected from the furnace it is the sum of bonnet pressure, filter loss, casing loss, losses through air washers, coils, and other devices. . . 9. Selection of Furnace. . .. ... A. Determine register delivery (the sum of room Btu losses); B. Determine bonnet capacity. . Bonnet capacity = (total cfm) X (temperature rise). X 1.089. C; Determine allowance .for pick-up load. For buildings which are heated in- termittently, such as cnurches and auditoriums, it is customary to add from 10 to 25 percent extra furnace capacity for warming of the structure. AUTOMATIC CONTROLS Air stratification, high bonnet temperatures, excessive flue gas tempera tures, and heat overrun or lag in a properly designed system, can be largely eliminated through proper care in the planning and installation of the con trol system;6 desirable controls usually employed are; 1. A thermostat located in a living room where maximum fluctuation in tempera ture can be expected, in order to secure frequent operation of fans, drafts, and burn ers. The thermostat location should not be on an outside waU, in a bedroom, bath room, or sun room, or in a location where it will be affected by direct radiant heat from Forced Warm Air Systems 103 102 101 69 98 97 96 95 94 93 26.0 26.6 27.3 28.8 29.6 30.5 31.5 32.3 33.3 34.6 97 96 95 94 93 92 91 90 90 30.5 31.6 32.3 33.3 34.6 35.9 37.3 38.6 38.6 240 87 42.7 8Tk 88 aOEn , sa> s3 A~ aeS* >Sfic3> o Ei- P* o S3 g | a > g > 31 gSo-.S 3^ Z J*s P5 jc e B3 .31 Big a<Kcu o V. HS Sq gS .&e .So, g 2 (33 CO 3 *. 55 fe, O g a a GO aa A < H I 170 93 02 91 90 90 89 89 ' 88 34.6 35.9 37.3 38.6 38.6 39.9 39.9 41.3 oCO oCC3* o N OoC4 .8 ost 1 oCD O CO OOO O74S . co 00 S3 3 8 OK 1 95 32.3 S occ to (oOeHo 130 128 126 123 121 119 117 115 113 111 110 108 107 105 15.9 16.4 16.9 17.6 18.1 18.7 19.3 20.0 20.7 21.6 22.1 23.1 23.6 24.8 102 101 100 26.6 27.3 28.0 | no 103 102 101 100 99 98 97 26.0 26.6 27.3 28.0 28.8 29.6 30.5 108' 107 106 23.1 23.6 24.2 o o < g s s oto c* sa eo C4 O fci o'"! U > 120 118 116 1 114 112 111 109 108 108 105 18.4 19.0 19.6 20.3 21.1 21.6 22.5 23.1 24.2 24.8 5 WH 137 134 131 129 126 124 122 120 118 116 114 112 110 109 107 106 105 103 102 101 100 99 98 97 14.6 15.1 15.7 16.2 16.9 17.3 17.9 18.4 19.0 19.6 20.3 21.1 22.1 22.5 23.6 24.2 24.8 26.0 26.6 27.3 28.0 28.8 29.6 30.5 150 147 143 12.6 12.9 13.5 1 160 156 1 152 11.4 11.8 i 12.3 140 14.0 149 12.7 137 14.6 145 13.2 134 15.1 142 13.7 131 16.7 139 14.2 129 127 16.2 16.6 136 '133 14.8 15.3 124 17.3 130 15.9 122 17.9 128 16.4 120 118 | 116 18.5 .18.4 19.6 126 '123 121 18.9 17.6 18.1 114 20.3 119 18.7 112 21.1 117 19.3 110 22.1 115 20.0 109 22.5 113 20.7 107 23.6 106 105 24.2 24.8 i 110 108 22.1 23.1 103 102 26.Q .26.6 107 108 23.6 24.2 101 27.3 104 25.4 100 28.0 103 26.0 459 0` Register delivery volumes in column 1 for zero length of duct. , 138 136 132 129 127 125 122 120 118 116 114 14.4 14.9 16.6 16.2 16.6 17.2 17.9 18.4 19.0 19.6 20.3 119 117 115 113 1 112 18.7 19.3 20.0 20.7 21.1 118 116 115 113 111 19.0 19.6 20.0 20.7 21.6 116 114 112 1110 109 107 106 19.6 20.3 21.1 22.1 22.5 23.6 24.2 VZZ on Register temperature, Fahrenheit. (Use upper value in each group). . 1Register delivery volume in oubio feet per minute per 1000 Btu. (Use lower value in each group). 171 167 163 158 154 161 147 144 10.4 10.7 11.1 11.6 12.1 12.4 12.9 13.4 160 156 153 149 145 142 139 136 133 11.4 11.8 12.2 | 12.7 13.2 13.7 14.2 14.7 15.3 157 153 150 146 143 140 137 135 131 128 126 124 122 11.7 12.2 12.6 , 13.1 13.5 14.0 14.6 14.9 15.7 18.4 16.9 17.3 17.9 124 17.3 w <M1 H HC4 0p0i Sod WW OH CHICHD *"C W . o. CHO 30 128 16.4 H pH 131 128 126 124' 122 15.7 16.4 16.9 17.3 17.9 ^COWU) 170 168 161 157 153 150 146 143 140 137. 10.5 10.8 11.3 11.7 12.2 12.6 13.1 13.5 14.0 14.6 174 169 10.1 10.6 601 991 B II 801 191 991 <o o wen 175 170 10.0 10.6 swo OCQ wa> 0w0 o coo *-* o oWo? ar> coo 2oo 200 8.6 460 CHAPTER 19 1952 Guide Forced Warm Air Systems 461 Table 7. Determination of Free Area and Pressure Loss of Register for 22 Deg Deflection of Air*' b- d> Register Free Area in Square Inches (Upper value in each group) Pressure Loss in Incites of Water (Lower value in each group) Cfm Up to 59 Residential Use Reg. Size OR Equiv alent 10x4 10x6 Pres sure Loss .01 .01 Rej9IDENT1AL USE ' Cfm 100-119 ~ R EO. . . S ze 1 cB j Eq nivAL ENT 1 12 X 6 14x4 ' Pres- . - Cfm SURE - Loss ` .02 .02 700-739 Distance From-Register to Opposite Wall 31-34 35-39 40-49 50-59 B0^59 70-79 80-89 AB 243 186 127 85 0.02 0.03 0.06 0.11 60-69 10 x 6 12x4 .01 [ 120-129 .02 12 x 6 14x6 .02 .02 740-779 271 208 141 94 0.02 0.03 0.05 0.10 - 70-99 10 x 6 12 x 6 .02 1 130-169 ' 14 x 6 .02 .02 780-819 230 157 105 0.02 0.05 0.09 . ,. Cfm 190-209 170-189 14 x 8 .02 Distance From Register to Opposite Wall Up TO 19-21 22-24 25-27 28r30|31-34 35-39 40-49 50-59 18 A 68 49 38 29 24 .19 0.02 0.03 0.05 0.08 0.11 0.16 820-859 860-899 900-930 254 173 115 0.02 0.04 0.08 278 190 126 0.02 0.04 0.08 304 207 138 \ 0.02 0.04 0.07 210-229 . 82 60 0.02 0.03 45 35 28 23 0.04 0.06 0.10 0.13 230-249 22 1 71 54 42 34 28 0.02 0.04 0.06 0.08 0.11 0.17 940-979 980-1019 332 0.02 226 0.03 151 0.07 108 0.12 360 245 163 118 0.02 0.03 0.06 0.11 . 250-269 84 63 49 40 32 25 0.02 Q.03 0.05 0.07 0.10 0.16 1020-1059 390 265 177 127 0.02 0.03 0.06 0.11 270-299 100 76 60 48 38 30 0.02 0.03 0.04 0.06 0.09 0.13 1060-1099 285 190 137 0.03 0.06 0.10 300-339 96 .73 60 48 37 0.02 0.04 0.05 0.07 0.11 1100-1139 307 204 147 0.03 0.05 0.09 340-379 122 95 78 .61 47 33 0.02 0.03 0.04 0.06 0.09 0.16 1140-1179 330 220 158 0.02 0.05 0.09 380-419 420-459 117 . 94 75 58 39 0.02 0.03 0.05 0.08 0.15 142 113 91 70 47 0.02 0.03 0.04 0.06 0.13 1180-1219 1220-1259 353 235 169 0.02 0.04 0.08 376 251 180 0.02 0.04 o.os -- 460-499500-639 168 135 108 83 56 0.02 0.03 0.04 0.06 0..11 159 126 97 66 0.02 0.03 0.05 0.10 1260-1299 1300-1339 401 0.02 426 0.02 267 0.04 284 0.04 192 0.07 204 0.07 136 0.13 -- 144 0.13 540-4)79 185 147 113 77' 0.02 0.03 0.04 0.08 1340-1379 452 301 217 154 109 0.02 0.04 0.06 0.12 0.22 580-619 212 169 130 88 51 0.02 0.03 0.04 0.08 0.18 1380-1419 479 319 230 163 116 0.02 0.04 0.06 0.12 0.21 ,620-659 192 147 ioo 59 0.02 0.03 0.07 0.15 1420-1459 '508 338 244 172 122 0.02 0.03 0.06 0.11 '0:20 660-699 217 166 113 75 0.02 0.03J 0.06 0.13 1460-1500 536 0.02 356 0.03 256 0.06 o18:i2o 129 0.19 AB ' .` A' B' 1 If register selected based on distance from register to opposite wall is unsatisfactory on account of size or pressure loss, it is permissible to shift one or more spaces left or right in the tables to obtain a more suitable register. If re Quirements fall in blank space, select two registers in place of one and divide CFM capacity between the two registers. b Pressure loss is based on FLAT FACE ADJUSTABLE BAR TYPE and does NOT include stackhead. c Values on the right of line A and A' should not be used in applications such as churches, auditoriums, and con cert halls. . ,, d Values on right of line B and B' should not be used in applications such as residential work, motion picture thea ters, court rooms and schools. , *. CFM X 144 For floor and baseboard registers where a velocity of approximately 300 FPM is need, the free area =------ ^qq------ CFM or approximately, 2 ` Assume a pressure loss of .01. 462 CHAPTER 19 1952 Guide Table 8. Determination of Free. Area and Pressure Loss of Register for No Deflection of Air*- b*cd' e Register Free Air in Square Inches (Upper value inreach group) Pressure Loss in Inches of Water Column (Lower value in each group) CFM Distance fsom RsoxarrsB to Opposite Wall 19-21 |22-24|25-27|28-30I31-34| 35-39 140-491 50-59 60-69 190^-209 tb 63 47 37 so 24 18 0.02 0.03 0.04 0.06 0.09 0.15 CFM 660-699 Distance non Rsgxstbb i ' Opposite Wall 35 39140 49| 50-59 160-69 | 70-79 180-89 /1' E 210 143 95 69 49 0.02 0.03 0.07 0.12 0.22 210-229 76 58 45 36 29 23 0.02 0.02 0.04 0.05 0.08 0.12 700-739 236 160 107 77 54 0.02 0.03 0.06 .0.11 0.21 250-219 69 53 43 34 26 0.02 0.03 0.04 0.07 0.11 740-779 262 179 119 86 61 0.02 0.03 0.06 0.10 0.18 250-269 .81 63 50 40 31 31 0.02 0.03 0.04 0.06 0.09 0.18 780-819 291 198 132 95 67 0.02 0.03 0.05 0.09 0.17 270-299 93 73 69 47 36 24 0.02 0.02 o.os 0.05 0.03 0.16 820-859 320 218 145 105 74 0.02 0.03 0.05 0.08 0.15 300-339 95 77 61 46 32 0.02 0.03 0.04 0.06 0.12 860-899 352 240 160 115 81 0.02 0.02 0.04 O.OS 0.14 340-379 120 97 77 59 40 0.02 0.02 0.03 0.05 0.10 900-939 385 262 175 126 89 0.01 0.02 0.04 0.07 0.13 380-419 119 95 73 50 0.02 0.03 0.04 0.08. 940-979 419 285 190 137 97 0.01 0.02 0.04 0.07 0.12 420-459 149 114 88 60 0.02 0.03 0.04 0.07 980-1019 455 309 206 148 105 0.01 0.02 0.04 0.06 0.11 460-499 171 136 105 71 0.02 0.02 0.03 0.06 1020-1059 493 335 223 161 113 0.01 .0.02 0.03 0.06 .0.11 00-539 160 123 84 0.02 0.03 0.05 1060-1099 530 361 241 173 123 0.01 0.02 0.03 0.06 0.10 540-579 186 143 97 0.02 0.02 0.05 65 47 0.09 0.17 1100-1139 571 388 258 136 132 93 0.01 0.02 0.03 0.05 0.09 0.17 580-619 213 164 0.02 0.02 111 74 54. 0.04 0.08 0.15 1140-1179 416 277 199 141 100 0.02 0.03 0.05 0.08 0.16 620-659 180 0.02 127 85 . 61 0.04 0.07 0.14 1180-1219 . AB a If register selected based on distance from register to oppo site wall is unsatisfactory on account of size or pressure loss, it is permissible to shift one or more spaces left or nght in the tables to obtain a more suitable register. If requirements fall in blank. space, select two registers in place of one and divide CFM capaoity between the two registers. b Pressure loss is based on FLAT FACE ADJUSTABLE BAR TYPE and does NOT include stackhead. ' c Values on the right of line A and A' should not be used in ap plications 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. . e For floor and baseboard registers where a velocity of ap proximately 300 FPM is used, the free area = or aP . . CFM. . . ... proxunateJy, --^-- Assume a pressure loss ot .01. * For any volume under 190 CFM use Table 7. 1220-1259 1260-1299 1300-1339 1340-1379 1380-1419 1420-1459 1460-1500 446 297 214 151 107 0.02 0.03 0.04 O.OS 0.15 476 317 228 161 116 0.02 0.03 0.04 0.07 0.14 507 338 243 172 122 0.01 0.02 0.04 0.07 0.13 539 359 258 183 130 0.01 0.02 0.04 0.07 0.12 882 274 195 138 0.02 0.04 0.07 0.12 403 290 206 146 0.02 "0.03 0.06 0.12 308 218 155 0.03 0.06 0.10 324 230 183 0.03 0.06 0.10 Forced Warm Air Systems 463 Table 9. Suggested BoAnet 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 Trhough Any One Duct Suggested '. Bonnet Pressure . , In. Water 3500 to 5000 5000 to 7500 7500 to 10,000 10,000 to 12,000 ' 12,000 to 14,000 0.15 0.25 0.375 0.500 0.750 the sun or from a fireplace, or by direct heat from any warm air duct, register or chimney. . 2. A fan switch control located in the bonnet to start blower operations at tempera tures between 110 and 130 F, and to stop the blower at about 25 to 30 deg below the cut-in point. The lower settings are used for high sidewall register installations, and the higher settings for baseboard register installations. For most satisfactory results these settings should be as low as.is feasible. . 3. A protective high limit switch located in the bonnet to stop, the system inde pendently of the thermostat if the bonnet temperature exceeds 175 F. 4. On 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 that the fire is dying, or a time interval contactor is used to cause the stoker to run a few minutes out of each hour. : 6. A humidistal to regulate the moisture supplied to the rooms, located either in one of the rooms or in the main return duct near the furnace. ; ADJUSTMENT OF SYSTEM FOR CONTINUOUS AIR CIRCULATION 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) in the furnace bonnet or warm air v plenum controls the blower operation. This procedure as outlined in detail in Manual 6 of the National Warm Air Healing and Air Conditioning As sociation, is as fpllows :7 1. Adjust the fuel input in proper relation to the heat loss of the Structure. 2. Determine the temperature rise through the furnace. . 3. Adjust the air volume to produce a temperature rise through the furnace of 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 distri bution between rooms. - 8. Set the room thermostat at the desired room temperature. WARM AIR CEILING PANEL SYSTEMS . Warm air ceiling panel heating systems utilize a false ceiling suspended 3| 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 ,464 CiH'A PTER 19 1952 Guide Table 10. PressureDrop in Duct . Inches of Water per 100 Feet of Duct Length EQUIVA LENT OPTotal Pressure Drop in Duct (In Water) Duct (Ft) 0.04 0.05 0.06 0.07 0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18 0.19 0.20 35-44' 45-54 , :o;io .0.08 0.13 0.1c 0.15 0.12 0.18 0.14 0.20 O.lt 0.23 0.11 0.25 0.2C 0.28 0.22 0.30 0.24 0:33 0;26 0.35 0.2i 0.38 0.30 0.40 0.32 0.43 0.45 0.34 .0.36 0.48 0:38 0.50 0.40 55-64 65-74;? 0.07 0.06 0.08 0.07 0.1C 0.09 0.12 0.10 0.13 0.11 0.15 0.17 0.13 0.14 0.1S 0.16 0.2C 0.17 0.22 0.19 0.23 0.20 0.25 0.21 0.27 0.23 0.2C 0.24 0.30 0.26 0.32 0.28 0.33 0.29 75-84 85-94 95-104 105-114 .0.05 0.05 0.04 0.04 0.06 0.06 0.05 0.05 0.08 0.07 o.oe 0.05 0.09 0.01 0.07 0.06 0.10 O.OJ 0.03 0.07 0.11 0.10 0.0s 0.08 0.13 0.11 0.10 0.09 0.14 0.12 0.11 0.10 0.15 0.13 0.12 0.11 0.16 0.14 0.13 0.12 0.18 0.16 0.14 0.13 0.19 0.17 0.15 0.14 0.20 0.18 0,16 0.1s 0.21 0.19 0.17 0.15 0.23 0.20 0.18 0.16 0.24 0.25 0.21 .0.22 0.19 0.20 0.17 0.18 ` 115-129 130-149 ' 0.03 0.02 0.04 0.04 0.05 0.04 0.06 0.05 0.07 0.06 oios 0.07 0.08 0.07 0.09 0.06 0.10 0.09 0.11 0.09 0.12 0.10 0.12 0,11 0.13 0.11 0.14 0.12 0.15 0.13 0.16 0.14 0.17 0.14 150-169 0.02 0.03 0.04 0.04 0.05 0.06 0.06 0.07 0:08 o.oa ,0.09 0.09 0.10 0.11 0.11 0.12 0.13 . 170-189 . 0.02 0.03 0.03 0.04 0.04 0.05 0.06 0.06 0.07 0.07 0.08 0.08 0.09 0.09 0.10 0;11 0.11 190-214 215-239 . 240-264 ' 0.02 0.03 0.03 0.02 .0.02 .0.02 0.02 0.02 0.02 0.04 0.03 0.03 0.04 0.04 0.03 0.05 0.05 0.04 .0.05 0.04 0.04 0.06 0.05 0.04 0.06 0.05 0.05 0.07 0.06 0.05 0.07 0.06 0.06 0.08 0.07 0.06 0.08 0.07 0.06 0.09 o.oa 0.07 0.09 0.08 0.07 0.10 0.09 0.08 0.10 0.09 0.08 265-289 0.01 0.02 0.02 0.03 0.03 0.03 0.04 0.04 0.04 0.05 0.05 0.05 0.06 0.06 0.07 0.07 0.07 290-324 325-374 .375-424 425-474 0.01 0:02 0.02 0.03 0.03 0.03 0.03 0.04 6.04 0.04 0.05 0.05 0.05 0.06 0.06 0.06 0.07 0.01 0.01 0.02 0.01 0.02 0.02 0.02 0.02 0.02 0-.02 0.03 0.02 0.03 0.03 0.03 0.03 0.03 0.03 0.04 0.03 0.04 0.04 0.04 0.04 0.05 0.04 0.05 0.04 0.05 0.05 0.05 0.05 0.06 0.05 0.01 0.01 0.01 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0.03 0.03 0.04 .0.04 0.04 0.04 0.05 475-524 0.01 0.01 0.01 0.02 0.02 0.02 0.02 0.02 0.02 0,03 0.03 0.03 0.03 0.03 0.04 0.04 0.04 525-574 . 0.01 0.01 0.01 0.01 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0.03 0.03 0.04 575-625 0.01 0.01 0.01 0.01 0.01 0.02 0.02 0.02 0.02 0.02 0.02 0.03 0.03 0.03 0.03 0.03 0.03 ' Equiva- Total Pressure Drop in Duct (In. op Water) Duct (Ft) 0.21 0.22 0.23 0.24 0.25 .0.26 0.27 0.28 0.29 0.30 0.32 0.34 0.36 0-38 0.40 0.45 0.50 35-44 45-54 55-64 65-74 0.53 0.55 0.58 0.60 0.63 0.65 0.68 0.70 0.73 0.75 0.80 0.85 0.90 0.95 1,00 1.13 1.25 0.42 0.44 .0.46 0.48 0.50 0.52 0.54 0.56 0.58 0.60 0.64 0.68 0.72 0.76 0.80 0.90 1.00 0.35 0.37 0.39 0.40 0.42 0.43 0.45 0.47 0148 0.50 0.53 0.57 0.60 0.64 0.67 0.75 0.83 0.30 0.32 0.33 0.34 0.36 0.37 0.39 0.40 0.42 0.43 0.46 0.49 0.52 0.54 0.57 0.64 0.72 75-84 85-94 ; . 95-104 105-114 0.26 0.23 0.21 0.19 0.28 0.25 0.22 0.20 0.29 0.26 0.23 0.21 0.30 0.27 0.24 0.22 0.31 0.28 0.25 0;23 0.33 0:29 0.26 0.24 6.34 0.30 0.27 0.25 0.35 0.31 0.28 0.26 0.36 0.32 0.29 0.27 0.38 0.33 0.30 0.28 0.40 0.36 0.32 0.29 0.43 0.38 0.33 0.31 0.45 0.40 0.36 0.33 0.48 0.50 0.42 0.45 0.38 0.40 0.35 0.37 0.56 0.50 0.45 0.41 0.63 0.56 0.50 0.46 115-129 0.18 0.18 0.19 0.20 0.21 0.22 0.23 0.23 0.24 0.25 0.27 0.28 0.30 0.32 0.33 0.38 6.47 130-149 0.15 0.16 0.16 0.17 0.18 0.19 0.19 0.20 0.21 0.21 0.23 0.24 0.26 0.27 0.29 0.32 0.36 150-169 0.13 0.14 0.14 0.15 0.16 0.16 0.17 0.18 0.18 0.19 0.20 0.21 0.23 0.24 0.25 0.28 0.31 170-189 ' 0.12 0.12 0.13 0.13 0.14 0.15 0.15 0.16 0.16 0.17 0.18 0.19 0.20 0.21 0.22 0.25 0.28 190-214 215-239 r 240-264 265-289 0.11 0.11 0.12 0.12 0.13 0.13 0.14 0.14 0.15 6.15 0.16 0.17 0.18 0.19 0.20 0.23 6.25 0.09 0.10 0.10 0.11 0.11 0.12 0.12 0.13 0.13 0.13 0.14 0.15 0.16 0.17 0.18 0.20 0.22 0.08 0.09 0.09 0.10 0.10 0.10 0.11 0.11 0.12 0.12 0.13 0.14 0.15 0.15 0.16 0.18 0.20 0.08 0.08 0.08 0.09 .0.09 0.10 0.10 0AQ 0.11 .0.11 0.12 0.12 0.13 0.14 0.15 0.16 0.18 290-324 . '`325-374 ' 375-424 425-474 0.07 0.07 0.08 0.08 0.08 0.09 0.09 0.09 0.10 0.10 0.11 0.11 0.12 0.13 .0.13 0.15 0.17 0.06 0.06 0.07 0.07 0.07 0.08 0.08 0.08 0.09 0:09 0.09 0.10 0.10 0.11 0.11 0.13 0.14 0.05 0.06 0.06 0.06 0.06 0.07 0.07 0.07 0.08 0.08 0.08 0.09 0.09 0.09 0.10 0.11 0.13 0.05 0.05 0.05 0.05 0.06 0.06 0.06 0.06 0.07 0.07 0.07 0.08 0.08 0.09 0.09 0.10 0.11 475-524 525-574 . 575-625 0.04 0.04 0.05 0.05 0.05 0.05 0.05 0.06 0.06 0.06 0.06 0.07 0.07 0.08 0.08 0.09 0.10 0.04 0.04 0.04 0.04 0.05 0.05 0.05 0.05 0.05 0.06 0.06 0.07 0.07 0.07 0.07 0.08 0.09 0.04 0.04 0.04 0.04 0.04 0.04 0.05 0.05 0.05 0.05 0.05 0.06 0.06 0.06 0.07 0.08 0.08 are installed through these hangers and metal lath is attached to the rods. The lath is then plastered to a thickness of J in., making a completely sealed air space above the ceiling. Warm air is delivered to this sealed space through 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 ceiling, 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 23, Panel Heating.) . Forced Warm Air Systems' 465 Becatise a warm air ceiling pazrel system involves a different type .of ceiling construction, its installation is practically limited to new construe-: 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 given* in Manual 7-A of the National Warm Air Healing arid Air Conditioning Association. This procedure is given in the following general outline: . 1. Calculate .the design heat losses from individual spaces in the structure. (See Chapter 11.) _ _' ; .. ; . a. Determine furnace size from tables in Manual 7-A. > > ' . ` b. Determine fan (blower) size from tables in Manual 7-A. :: 2. Lay out the ceiling panel design, locating panel inlets and outlets, and make a tentative drawing of supply and return system. 3. Measure actual length of warm air travel from plenum to discharge into panel. 4. Determine equivalent length of fittings, including panel inlet connection to ' panel, from values given in Manual 7-A. 5. Select duct sizes required from capacity tables and check minimum allowable : .. panel area.. .. .: 6. Measure actual length of return air travel from warm air outlet into panel to . connection at blower cabinet. . p ... . 7. Determine equivalent length of fittings and. turns from warm air outlet into panel to blower inlet. ................ ` :. 8. Add actual lengths and equivalent lengths, determine, width of space 3) in. deep that may be used, and find the size of the return air duct required.1 9i- Determine both warm air and return air trunk sizes. . / . WARM AIR PERIMETER SYSTEMS Warm air perimeter heating systems are combination panel and convec tion systems that have been developed especially for structures having a concrete-slab floor laid on the ground. Warm air is delivered from the furnace-blower unit through round ducts imbedded in the concrete floor slab to a continuous duct along the outer perimeter of the house just in side the exterior walls. The warm air is introduced into the rooms through registers which are connected to the ducts,, and are located under windows or at the points of greatest heat loss. The return air is collected through one or more grilles located high on the interior sidewalls or in the ceiling. 466 CHAPTER 19 ' 1952 Guide A suggested procedure9 for the design and installation of a warm air perimeter heating system is given in Manual 4 of the National Warm Air Heating and Air Conditioning Association. This procedure follows the general outline: . ... . 1. Calculate design heat losses from individual spaces in the structure. (See Chapter 11.) Calculate design heat losses, below grade using table in Form 5,10 . . which accompanies Manual 4. . ; . 2. Lay out perimeter system design, locating ducts, registers, and return air . grilles or intakes. !. 3. Determine length from furnace to each register using shortest distance. _ 4. Determine register sizes from tables in Form 5. .* 5. Determine size of return-air intake and ducts from tables in Form 5. The furnace may be either, the down-flow or the conventional up-flow type, in most cases, the down-flow type is preferred since it requires a minimum amount of floor area and ductwork, and eliminates the need for a duct to bring the warm air down from thetop of the furnace, or a duct to bring the return air down to the blower inlet. . Fig. 5. Cboss-section of Slab Construction Containing Perimeter Duct8 Several arrangements of perimeter ducts may be used, 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, as is shown in Fig. 4. 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 is away from the slab, and where there is no standing water at any 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 eflect may be obtained under certain conditions by the circulating basement air. A more positive cooling effect may be obtained Forced Warm Air Systems 467 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 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 cold 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 and doors should be tight, and awnings should be supplied on the sunny side of the building. See also Chapters 29, 36 and 37. Conclusions drawn from studies11 conducted in the University of IUtnois Research Residence, subject to the limitations of the test are: 1. An uninsulated building of ordinary residential type may require the equivalent of three tons of ice in 24 hr on days when the maximum outdoor temperature reaches 100 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 in savings of from 20 to 30 percent in the required cooling load. 3. The cooling load per degree difference in temperature is not constant, but in creases as the outdoor temperature increases. .. 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. . ' DESIGN OF COOLING SYSTEM The general procedure which may be used for the design of a summer cooling system in a forced-air installation is: 1. Calculate heat gain for each room or space to be conditioned. (See Chapters 9 and 12.) Allowance for addition of outside air must be included in this calculation. 2. Select a temperature of air leaving supply inlets. In University of Illinois Research Residence tests, a value of from 65 to 70 F was found satisfactory. 3. Determine indoor conditions to be maintained. In the Research Residence, 80 F dry-bulb and 45 percent relative humidity were found satisfactory. 4. Determine the quantity of air to be introduced into each room. - 5. Estimate heat loss in duct system between cooling unit and supply registers. 6. Calculate the sensible and latent heat to be removed by the cooling unit. 468 CHAPTER 19 19S2 Guide - 7. Determine size of ducts in duct system and size of registers, as explained in this chapter. 8. Determine pressure loss in duct system and select fan having proper capacity. 9. Select cooling unit from manufacturer's data. Specify temperature and pres sure of available cooling water, voltage and characteristics of electrical supply, and method of control of apparatus. 10. Select cooling coils from manufacturer's data to take care of latent heat load and to give required drop in air temperature with the weight of air flowing. (See Chapter 35.) . . 11. If system is to be used for both winter heating and summer cooling, duct sizes must be checked to insure that velocities and friction losses are reasonable for both conditions of operation. Adjustable dampers will be necessary to'make changes in air distribution for the two. seasons.- Provision-must also be made:for changing fan speeds for summer and winter operation. . 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). 1 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). . .. . * Code and Manual for the Design and Installation of Warm Air Winter Air Con ditioning Systems (National Warm Air Heating and Air Conditioning Association, Manual 7, Second Edition, 1947). ,. . 4 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,-Vo] . 53, 1947, p. 177). .. , ... .5 Code and Manual for the Design and Installation of Large Warm Air Winter Air , Conditioning Systems (National Warm Air Healing and Air Conditioning Association, Manual 9, Fourth Edition, 1950). . .. * Automatic Controls for FoTced-Air Heating Systems, by S. Konzo and A. F. Hubbard (A.S.H.V.E. Transactions, Vol. 40,1934, pi 37).. . I Service Manual for Continuous Air Circulation Technicians (National Warm Air Heating and Air Conditioning Association, Manual 6, First Edition, 1947). = ".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, Second Edition, 1948). _. Warm-Air Perimeter Heating (National Warm Air Heating and Air Conditioning Association, Manual 4, First Edition, 1950). . 10 Work Sheet for Warm-Air Perimeter Systems (National Warm Air Healing and Air Conditioning Association, Form 5, Second Edition, 1950).: , II 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 Report 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 20 STEAM HEATING SYSTEMS Classification of Steam Heating Systems by Types; One-pijie; 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 prig; 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 in the systern 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 ing 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 form a U-shaped container, with the boiler steam pressure on the top of the water at one end, and the steam mam pressure on the top of the water at the other end. The difference between these two pressures is.the pressure drop in the system, 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 balance the pressures, and it will rise far enough to produce a flow through the return pipe 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 i psi, and utilizes a Hartford return connection instead of a check valve on the return, 469 f- 470 CHAPTER 20 1952 Guide the rise in the water level at the far end of the return, due to the difference in steam pressure, would be J of 28 in. (28 in. head being equal to one pound per square inch), or in. Adding 3 in. to overcome the resistance of the return main, and 6 in. as a factor of safety for heating up, gives 12J 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, and either traps or pumps must be employed, the system is known 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 return and a forced return system, a boiler return trap or alternating receiver is employed and the system may be known as an alternating return system. . When condensate is pumped to the boiler under pressures of the atmosphere or above, the system is known as a condensate pump return system. Steam Heating Systems 471 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 as shown in Fig. 5 Chapter 24. - There are several variations in the piping arrangement of a one-pipe system as follows: ' 1. Up-feed one-pipe systems where the radiators and other heating units are lo 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 radiatoror 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 lo cated above the mains, and the mains are dripped at each radiator connection to a wet- , j ! 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 472 CHAPTER 20 1952 Guide Fig. 6. Typical Up-Feed Gravity One-Pipe Air-Vent System dr 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 more 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- jjipe systems must be either fully opened or fully closed. No throttling or modulating- position caii 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-logged heating unit itself. ' TWO-PIPE SYSTEMS Two-pipe systems, as previously defined, are systems in which steam mid '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 .thay be employed. Fig. 7. Typical Steam Runout where Risers are Dripped Steam Heating Systems 473 Two-Pipe High Pressure Systems :: . Two-pipe high pressure systems operate at pressures above, i5 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 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 sys tems, because they have, the disadvantage' of not holding heat when the rate of steam generation is diminishing. . They also have the disadvantage of 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 con densate 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 474 CHA/P-TER 20 , 1952 Guide Steam Heating Systems 475 range of the average vapor system. Fig. 9 illustrates a typical low pressure system with condensate pump.' Two-Pipe Vapor Systems Two-pipe vapor systems operate at pressures varying from 20 in. vacuum or more (depending upon the tightness with which the system is assembled) to 15 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 piping connections are essential with special appliances for pressure equalizing and air elimination. Fig. 12. Detail of Drip Connec- tions at Bottom of DownFeed Steam Drop ' Fig. 13. Typical Connections for Automatic Return Trap 476 CHAPTER 20 1952 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 thevalve. ' 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 (luring 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 retum risers are connected in the basement into a common return main which slopes downward toward the vacuum pump. The vacuum Steam Heating Systems 477 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 tp 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 tp 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 oh 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 may reach as high as 25 in. Hg, after which further reduction in heat output is obtained by restricting the quantity of steam. . . ., The rate of steam supply is controlled by a valve in the steam main or by thermostatically controlling the rate of steam production in the boiler. 478 CHAPTER 20 1952 Guide The control valve may be of the automatic modvlaling 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. Fid. 16. Method of Making Lifts on Vacuum Systems when Distance is Over 5 ft ' Fio. 17. Detail of Main Return 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 as the 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 479 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 14.7 + 2.0 0.90 or 90 percent. Should the steam pressure be dropped to J 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 with 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 dose. 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 fadli- 480 CHAPTER 20 ... 1952 Guide 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,umt back to.tl^e boiler, tends to obtain such a result. The '. Table 1. Obifice Capacities fob Low Pbessube Steam Stbtems ' This table'is baaed on data from actual teste* ' " Games1:' Diameter- ' 64ths of an Inch : - 6, IN. He 1 . 5 IN* Hg 'Differential Differential 4 in. Hg. r: - 2 in. Hg 1 IN. He Differential Differential Differential Capacity Expressed in Square Feet E D R - . - 7g. 18-23 23-29 16-21 21-27 V ' (9: - - ;29-36 A 27-33 ,10 / 36-44 i ; 33-40 ,,.-..11 . ... 44^2 40-48 12 52% . 48-57 " . 13 1 ; . 62-7fc 57-66 ... - - 14 ` ' / 72-83 ; . 66-76 - 15 - 83-94 . 76-86 ... 16 .94^106 17 106^119 97-109 18 1 ' 119-133 109-T22 -19 133-148 122^135 20 , 14&-163 135-149 21 163-179 .. 149-164 15-19 ,, . 10-13 19-25 ' ' 13-17 25-30 17-21 30-37 . 21-26 37-44 26-31 44-51 31-37 51-59 37-43 59-67 43^49 67-76 49-66 :: 76-86 . 56-64 86-97 64-72 97-108 72-80 108-120 80-88 v/. 120-133 88-98 j, 133-145 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 : ' ; 7 . ' 4.5-5.8 8 - 5.S-7.3 9 7.3-9.0 . , 10 9.0-11.0 ,H : 12 11.0-13.0 13.0-15.5 13 ` 15.5-18.0 : 14 . 18.0-20.8 15 20.8-23.5 16 , : 17 23.5-26.5 ' 26.5-29.8 -. ;18 29.8-33.3 .19 33.3-37.0 , 20 37.0-40.8 ' 21 40.8-44.8 4.0-5.3 5.3-6.8 6.8-8.3 8.3-10.0 10.0-12.0 12.0-14.3 14.3-16.5 16.5-19.0 19.0-21.5 21.5-24.3 24.3-27.3 27.3-30.5 30.5-33.8 33.8-37.3 37.3-41.0 3.8-4.8 4.8-6.3 6.3-7.5 7.5-9.3 9.3-11.0 11.0-12.8 12.8-14.8 14.8-16.8 16.8-19.0 19.0-21.5 21.5-24.3 24.3-27.0 27.0-30.0 30.0-33.3 33.3 36.3 2.5-3.3 3.3-4.3 4.3-5.3 5.3-65 6.5-7.8 7.S-9.3 9.3-10.8 10.8-12.3 12.3-14.0 14.0-16.0 16.0-18.0 18.0-20.0 20.0-22.0 22.0-24.5 24.5-26.8 2.0-2.8 2.8-3.5 3.5-4.3 4.3-5.0 5.0-6.0 6.0-7.0 7.0-8.0 8.0-9.3 9.3-10.5 10.5-11.8 11.8-13.0 13.0-14.5 14.5-16.0 16.0-17.8 Note.--The radiator orifice plates recommended in this table are made of-brass stampingB 0.023 in. thick cu]>shaped to be inserted in radiator valve unions. . ., ' , ^ Flow of Steam Through Orifices into Radiators, by S. S. Sanford and C.B. Sprenger (A.S.H.V.E. Trans actions, Vol. 37, 1931, p. 371). i .: ; condensate, which occurs in steam piping as well as in radiators must be drained to prevent impeding the ready flow of the steam and 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 return, must be avoided. It is important that steam piping systems distribute steam not only at full, design Joad, but during excess and1 partial loads. Usually the average winter steam .demand,is less than half of the,demand at the "design outside Steam Heating Systems 481 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 unload. . 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 Fig. 18. Relation Between Elapsed Time, Steam Pbessube, Condensate and Aib Elimination Rates ............ ' pressures to be attained in' much shorter time intervals than those which are sluggish. Results are given in Fig. 18 from investigations^ 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 of the steam, and the pressure drop through the pipe. This relationship 482 CHAPTER 20 1952 Guide Table 2. Flow op Steam in Pipes P -- loss in pressure in pounds per square inch. D = inside diameter of pipe in inches. L = length of pipe in feet. d -- weight of 1 cu ft of steam. W = pounds of steam per hour. ' ,, I PdDi W = 5220 -A/ / ' 3.6\ V ( 1 + ~p \L 1' ' P = 0.0000000367 ( 1 + Col. 1 PurnHimn. Pips Sm IN . Ounces /~P~ Actual 52201*1--10--0. Nominal Internal Diameter Pipe Sq Inches Col. 2 iAvo Steam /* Press. V+* fsxq Col. 3 i-- V' Lenotb IN Fbet * Col. 4 1100 Vt 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 i 1.049 0.864 0.536 --1.0a 0.187 20 92.28 m 1.380 130.5 1H 1.610 184.6 2 2.067 1.496 2.036 3.356 1.178 --0.5a 0.190 1.828 0.0 0.193 3.710 0.3 0.195 40 60 80 226.0 24 2.469 4.788 6.109 1.3 0.201 100 261.0 3 3.068 7.393 11.183 2.3 0.207 120 291.8 319.7 34 3.548 4 4.026 9.887 12.730 16.705 5.3 0.223 23.631 10.3 0.248 140 160 345.3 *4 4.506 15.947 32.134 15.3 0.270 180 369.1 5 5.047. 20.006 43.719 20.3 0.290 200 412.7 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 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 . 500 690.5 14 13.250 137.880 566.693 125.3 0.557 600 738.2 16 15.250 182.655 816.872 150.3 0.603 700 825.4 904.1 1167.2 1650.7 2334.5 2859.1 Column 1 X 2X3X4 - lb of steam 175.3 0.645 800 pipe for a given condition. 200.3 Example 1: 1 ox drop -- 2 in. pipe -- 1.3 lb press. -- 100 ft equivalent length: 0.685 130.5 X 3.710 X 0.201 X 1 " 07.2 lb per hour. 97.2 X 4b > 388.8 sq ft equivalent radiation. 900 1000 1200 Table 2 does not allow for entrained water in low-pressure steam, condensation in covered pipe and roughness in com- mercial pipe as found m practice. . 1500 2000 2.240 1.580 T.290 1.120 1.000 0.912 0.841 0.793 0.741 0.710 0.632 0.578 0.538 0.500 0.477 0.447 0.407 0.378 0.354 0.333 0.316 0.289 0.258 0.224 a Pounds per square inch gage -- 2.04 in. Vacuum, Mercury Column. i _ b The factor 4 is the approximate equivalent in square feet of steam radiation of 1 lb of steam per hour. Steam Heating Systems 483 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: ' 1. 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 thi3 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 of condensate is limited and is flowing in the same direction as the steam, only the pressure drop need be considered. When the condensate mustflow against the steam, even in limited quantity, the velocity of the steam must not exceed limits above which the disturbance between the steam and 484 CHAPTER 20 1952 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. Compabative Capacity op Steam Lines at Vabious Pitches fob Steam and Condensate Flowing in Opposite Dibections* .. Pitch of Pipe in Inches per 10 Ft. Velocity in Ft per Sec . Pitch of Pipe Hin. H in. 1 IN. m in. 2 in. 3 in. 4 IN. 5 IN. 1 Capacity : Max. Vel , j Capacity Max. Vel. Capacity PTipnefthSfrifzl e .Capacity ; Capacity 1 Max. Vel. ! Max. Vel. Capacity '> i1 s Capacity 6> '3aa. ` - sS a S i Capacity Expressed in Square Feet EDR H 25.0 12 30.3 14 37.3 18 40.4 19 42.5 20 46.1 21 47.5 22 49.3 23 1 45.8 12 52.6 15 63.0 17 70.0 20 75.2 22 83.0 23 87.9 25 9L.2 26 1H 104.9 18 11712 20 133.0 23 144.5 25 154.0 27 165.0 28 172.6 29 178.2 31 1M 142.6 18 15910 21 181.0 23 196.5 25 209.3 27 224.0 28 234.8 30 242.6 31 2 . , 236.0 19 263.5 20 299.5 23 325.5 25 346.5 27 371.5 28 388.4 29 401.1 30 ' Capacity Expressed in Pounds per Hour M .1 1H 1H 2 6.3 12' 7.6 14 9.3 18 10.1 19 10.6 20 11.5 21 11.9 22 12.3 23 11.5 12 13.2 15 15.8 17 17.5 20 18.8 22 20.8 23 22.0 25 22.6 26 26.2 18 29.3 20 33.3 23 36.1 25 38.5 27 41.3 28 43.2 29 44.6 31 35.7 18 39.8 21 45.3 23 49.1 25 52.3 27 56.0 28 58.7 30 60.7 31 59.0 19 65.9 20 74.9 23 81.4 25 86.6 27 92.4 28 97.1 29 100.3 30 Data from American Society op Heating and Ventilating Engineers 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 Rim 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 5fc- Steam Heating Systems 485 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 J 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 op Pipe to be Added to Actual Length op Run-- ' Owing to Fittings--to Obtain Equivalent Length - Size of Pips Inches Length, in Feet to bb Added to Run * Standard Elbow Side Outlet Tee Gate Valve* Globe Valve* Angle Valve* a % 1H 2m r 3 S4 H 5 6 8 10 12 14 13 , 13 22 30 33 43 5.0 63 8 9 11 13 17 21 27 30 3 03 14 . 7 4 0.4 18 10 5 0.5 23 12 6 0.6 29 15 7 0.8 34 18 8 1.0 46 22 . 11 : 1.1 , 54 27 13 ; 1.4 66 34 15 1.6 80 40 18 1.9 92 45 22 ' 2.2 112. . 56 27 23 136 67 35 3.7 180 92 45 4.6 230 112 53 53 270 132 63 6.4 310 152 Valve In full open position. Example of length in .: feet ofpipe to be added to actual length of run. Measured Length'. -- '133.0 ft 4 in. Gate Valve ; 1.9.ft' .L.-------&?'0-----;4--4 in. Elbows - ' 36' .0 ft y ' t jEqulvalent Length " 169.9 ft .... 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 B to G, inclusive, are used where the steam and condensate flow in the same direction, while Columns H and I are for cases where the steam 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 486 CHAPTER 20 1952 Guid. Table 5. Steam Pipe Capacities fob Low Phessube 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 orAmerican Society Heating and Ventilating Engineers. , """ Pipe 8xzb In. A CAPACITIES OF STEAM MAINS AND RISERS Special Capacribb ron One-Pips Systems Only Direction or Condensate flow in Pipe IzTnb With the Steam in One-Pipe and Two-Pipe Systems A pai - or -i A pai A pai ip 1 Os .Drop 1 pai or aoz Drop 1 pai 4 0* Drop i pai 8 0s Drop Against the ator Supply Valves Two-Pipe Only Risers and Up- Vertical Peed Con Vertical Hori zontal nec tions Radi ator and Riser Run outs B c D B F G H* /c J* K IS Capacity Expressed in Square Feet E DR i 1 li 11 2 2| 3 31 4 5 6 8 10 12 16 - 30 30 39 46 56 79 in 157 56 34 87 100 122 173 245 346 122 75 134 155 190 269 380 538 190 108 273 315 386 546 771 1,091 386 195 449 518 635 898 1,270 1,800 635 395 822 948 1,160 1,650 2,330 3,290 1,130 700 1,230 1,420 1,740 2,460 3,470 4,910 1,550 1.150 1,740 2,010 2.460 3,480 4,910 6,950 2,040 1,700 3,210 3,710 4,550 6,430 9,090 12.900 4.200 3.150 5,280 6,100 7.460 10,550 14,900 21,100 7.200 5,600 11,000 12.700 15.500 21,970 31,070 43.900 15.000 12,000 20,000 23.100 28,300 40,100 56,700 80,200 28.000 23.000 32.000 37.100 45.500 64,300 91,000 129.000 46.000 38.000 61.000 69.700 84,800 121,000 170,000 242.000 88.000 76.000 25 45 98 152 288 464 800 1,140 1,520 28 62 93 169 28 62 93 169 260 475 745 1,110 2,180 Capacity Expressed in Pounds per Hour i 1 n H 2 21 3 31 4 5 6 8 10 12 16 8 10 12 14 20 22 25 31 43 34 39 48 67 68 79 97 137 112 130 159 225 206 237 291 411 307 355 434 614 435 503 614 869 806 928 1,140 1,610 1,320 1,520 1,870 2,640 2,750 3,170 3,880 5,490 5,010 5;790 7;090 .10,000 8,040 9,290 11,400 16,100 15,100 17,400 21,200 30,300 28 61 95 193 318 581 869 1,230 2,270 3,730 7,770 14,200 22,700 42,400 >8 40 14 9 87 31 19 135 48 27 273 97 49 449 159 99 822 282 175 1,230 387 288 1,740 511 425 3,210 1,050 788 5,280 1,800 1,400 11,000 3,750 3.000 20,000 , 7,000 5,700 32,200 ,11,500 9,500 60,500 22,000 19.000 6 11 20 38 72 116 200 286 380 -- -- -- 7 16 23 42 7 7 16 23 42 65 119 186 278 545 All Horizontal Mains and Down-Peed Risers Mains UpFeed Risers and Un dripped Run outs UpFeed Risers Radi ator Con nec tions Run outs Not Dripped Note.--Steam at an average pressure of 1 psig is used as a basis for calculating capacities. All drops shown are in pm per 100 ft of equivalent run--based on pipe properly reamed. * Do not use Column B for drops of 1/24 or 1/32 psi; substitute Column C or Column B as required. ' b Do not use Column J for drop 1/32 psi except on sizes 3 in. and over; below 3 in. substitute Column B. c Fitch of horizontal runouts to risers and radiators should be not less 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 Steam Heating Systems 487 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 of a system. Example 2: What pressure drop should be used for the steam piping of a system if the measured length of the longest run is 500 ft, and the initial pressure is not to be over 2-psig? . Solution: It will be 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 I psi and a length of run of 1,000 ft, the drop per 100 ft would be iV psi, while if the total drop were 1 psi, the drop per 100 ft would be A psi. In the first instance the pipe could be sized according to Column D for iV 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 the 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 condensate flow in the sam6 direction, use t^-psi drop (Column D). . 2. Where the riser runouts are not dripped and the steam and condensate flow in opposite directions, and alsoJn the radiator runouts where the same condition occurs, use Column L. 3. For up-feed steam risers carrying condensate back from the radiators, use Column J. 4. For down-feed systems, the main 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. 6. For the dry-return main, use Column U. 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 J psi. The return piping sizes should corre spond with the drop used on the steam side of the system. Thus, where ifr-psi drop is being used, the steam main and dripped runouts would be Steam Heating Systems 489 490 CHAPTER 20 ` 1952 Guide Table 8. Steam Pipe Capacities for 30 Psio Steam Systems* Capacity Expressed in Pounds per Hour (Steam and Condensate Flowing in Same Direction) . ' Pipe Size Inches . Drop in Pressure--Pounds peb IOO Ft in Length x :x X X = > * 2 'H 1. : . IK . 44 2 2H . 3 3H 4 5 6 . 8 10 12 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 38 45. 77 89 172 199 267 309 543 ' 627 924 1,030 1,630 1,880 2,450 2,830 3,460 - 4,000 - 6,400 .- 7,390 10,400 12,100 21,900 . 25,300 40,600 46,900 . 64,000' 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 at an average 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 ^-psi drop the sizing would be the same, as for fa 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 0, and the wet-return from Column AT. 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 i 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 general, 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. 9. 150, : Table Steam Pipe Capacities fob Psig Steam Systems* ' Capacity Expressed in Pounds per Hour ; (Steam and Condensate Flowing in Same Direction) Pipe Size ' Inches - ' X . Drop in --Pressure Psi per 100 Ft in Length X X X * .2 5 X' 1 1H 1H 2 - Vfy 3 m 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 82 185 287 585 959 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 19.5Q0 40,600 75,600 119,000 ' 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 50,400 105,000 165,000 307,500 * Note: Steam at an average pressure of 150 psig is used as the basis for calculating the above table. Steam Heating Systems 491 10. 30' Table Return Pipe Capacities fob psig Steam Systems? Capacity Expressed in Hounds per Hour Pipe Size Inches X i 1M : m 2 m 3 3H 4 5 6 ' Drop in Pressure--Pounds per 100 Ft in Length H 115 230 485 790 1,580 2.650 4,850 7,200 10,200 19,000 31,000 H 170 340 710 1,160 2.360 3,900 7,100 10,600 15,000 27,800 45,500 M 245 490 1,025 1,670 3,400 5,600 10,300 15,300 21,600 40,300 65,500 H 308 615 1,290 2,100 4,300 7,100 12,900 19,200 27,000 55,500 83,000 1 365 730 1,530 2,500 5,050 8,400 15,300 22,800 32,300 60,000 98,000 * Note: The above table is based on steam at pressures of 0 to 4 pais. 4. Supply mains, runouts to risers, or risers, should be dripped where 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 ran 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 1 psi the drop per 100 ft will be slightly less than -fa psi. It would be well in this case to use & 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 Bupply, 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. SIZING PIPING FOR ONE-PIPE VAPOR SYSTEMS Piping for one-pipe vapor systems is sized so as to permit only a few ounces pressure drop in the system. Otherwise, the method follows that outlined for sizing one-pipe gravity systems. 11 150Table . Return Pipe Capacities fob . psig Steam Systems* Capacity Expressed in Pounds per Hour . Pipe Size Inches a Drop in Pressure--Psi per 100 Ft in Length HMH 1 X 156 232 360 465 560 i 313 462 690 910 1,120 650 960 , 1,500 1,950 2,330 1^5 1,070 1,580 2,460 3,160 3,800 2 2,160 3,300 4,950 6,400 7,700 2X 3,600 5,350 8,200 10,700 12,800 3 6,500 9,600 15,000 19,500 23,300 3H 9.600 14,400 22,300 28,700 34,500 4 13,700 20,500 31,600 40.500 49,200 5 25.600 38,100 58,500 76.000 91,500 6 42,000 62,500 96,000 125,000 150,000 1 * Note: The above table ia based on steam at pressures of 1 to 20 peig. 2 890 1,780 3,700 6,100 12,300 20,400 37,200 55,000 78,500 146,000 238,000 492 CHAPTER 20 Table 12. Pipe Sizes fob One-Pipe Up-Feed' System Shown in Fig. 19 Part of System Section of Pipe Radiation Theoretical Practical Supplied Pipe size Pipe"size EDR Sq Ft (Inches) (Inches) Branches to radiators.: -- Riser.............................. Riser................... :.................. Riser...................................... Riser....................................... Riser...................... ................ Runout to riser.................... Supply main........................ Branch to supply main__ Dry return main................. Wet return main.................. Wet return main.................. Wet return main.................. a to & & to c c to d d to t e to / f tog g to h A to / f to k k 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 mm 3 3 3H . 3. m m 1 '` 1 1 2. 1H 2' m m 3 .3 3M 3 3 2 2 2 2 Fig. 19. Rises, Supply Main and Return Main of One-Pipe System 1952 Guide ' ---- ^--Rner- SIZING PIPING FOR TWO-PIPE HIGH PRESSURE SYSTEMS . Steam supply piping for two-pipe high pressure canbe sized for greater pressure drops than that of the return piping. For a system-using steam at 30 psig, the total pressure drop can he 5 to 10 pa, 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 dashing 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 i 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 heathjg 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 by Steam Heating Systems 493 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 I. 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 J 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 psi. In this case tiie steam mains would be sized from Column B, the radiator and Undripped riser runouts from Column 7; the risers from Column B, because Column H gives a drop in excess of ^ 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 sV 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 J in. in 10 ft. 2. Pitch of horizontal runouts to risers and radiators should not be less than $ 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 be dripped separately into a wetrreturn, 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 } to 1 psi. Systems in which,the maximum equivalent length does not exceed 200 ft preferably employ the. smaller pressure drop, while systems over 200 ft equivalent length of run, more frequently are designed for the higher drop, owing to the relatively greater saving in pipe sizes. For example, a system with 1200 ft longest equivalent length of run would employ a drop per 100 ft of \ psi divided by 12, or -jV psi. In this case, the steam main would be sized from Column C, Table 5, and the risers also from Column C (Column H could be used as far as critical velocity is concerned, but the drop would exceed the limit of ^ psi). Riser runouts, if dripped, would use Column C but, if undripped, would use Column I; radiator runouts, Column I; return risers, lower part of Column S, Tables 6 and 7; return runouts to radiators, one pipe size larger than the radiator trap connections. 494 CHAPTER 20 1952 Guide 'Notes on Vacuum Systems .. 1. It is not generally considered good practice to exceed f 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 radiators should not be less than $ 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. ' 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 vary 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 diaphragm. These valves also control the low pressures more closely under conditions of varying high pressures. Valves that shut oflF all steam are called dead end type. They are single seated, and some of them have pilot operation that provides close control of the reduced pressure. If a thermostatically controlled valve is installed Steam Heating Systems 495 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 tworstage reduction. If the radiation served is cast-iron, the A.S.M.E. 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 twostage 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 of piping to and from the reducing valve be such that they will pass the desired amount of steam with the maximum velocity desired. A common error is to make the size of the reducing valve the same size as that of the service, or outlet pipe size. Generally, this will make the reducing valve oversized, and 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 the other on the basis of 0.3 X 50,000 lb, or 15,000 lb. During the mild or reduced demand periods, steam will flow through the smaller valve only. During the remainder of the season, the larger valve is set to control at whatever low pressure is desired, and the smaller one at a somewhat lower pressure. . Thus, when steam flow is not at its maximum, the smaller valve is closed, but it opens automatically when the maximum 496 CHAPTER 20 1952 Guide steam demand occurs, because this maximum demand creates > a slight pressure drop in the service line. The installation 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 operated valves. '- - There should be a by-pass around each reducing valve 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 Fiq. 20. The Hartford Return 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 Steam . Cast-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. Return ' _ Cast-iron boilers are generally provided with return tappings on both sides, while steel boilers are generally equipped with only one return Steam Heating Systems 497- tapping. 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 normal 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 line to each boiler would require only half of the capacity of the entire system, or, if the boiler capacity were more than one-half the entire system load, the return would be sized on the 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. With returns pumped from a vacuum or receiver return pump, the size of the line may be calculated from the water rate on the pump discharge when it is operated, and the line sized for . a very small pressure drop; The relative boiler loads should be considered, as in the case of gravity 498 CHAPTER 20 1952 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 pennits the water to pass repeatedly through the cycle of vaporization, with subsequent condensation and return to the boiler. During such repeated cycles any incrustants of 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 tod 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 also frequently used where steam at suitable pressures is available, the steam being used afterward for building heating. The usual vacuum pump 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 special steam 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 conditions 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 499 For rating purposes3 vacuum pumps are classified as low vacuum and high vacuum. Low vacuum pumps are those rated for maintaining 5 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 5j 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 limits. 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 elec tric or steam driven. Their piston speed in feet per minute should not exceed 20 times the square root of the number of inches in their stroke. They are usually supplied with an air separating tank, open to atmosphere, placed on the discharge side of the pump, and at an elevation sufficiently 500 CHAPTER 20 1952 Guide Steam Heating Systems 501 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 io 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 its latent heat, and to allow condensate and air to pass as soon as it accumu 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 (I) 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 Fig. 25. Typical Float and . Thermostatic Trap 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 I 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 modem type of thermostatic trap consists of thin corrugated metal bellows or discs enclosing a hollow chamber. The chamber is either filled with a liquid, or a small amount of a volatile liquid, such as alcohol, is introduced. The liquid expands or becomes a gas when steam comes in contact with the expansive element. 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 lef[ of a length of pipe should also be pro-, vided ahead of the trap on unit heaters and similar apparatus to cool the condensate in order to help in the trap action. Thermostatic traps are made in sizes from $ OPTIONAL INLET i Fio. 23. Thebmostatic Trap Bellows Ttpe Fio. 24. Thermostatic Trap Disc Type . Fig. 27. Inverted Bucket Trap Fig. 28. Inverted Bucket Trap with Central Guide 502 CHAPTER 20 1952 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 i 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 tial pressure (usually 1 psi at least) between the inlet and outlet of the trap in order to Steam Heating Systems 503 bottom of the trap to the outlet of same. Inverted bucket traps are made in sizes from i 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 trap. The orifice, however, is adjustable for the pressure differential required. A gage glass or float indicates whether the trap is operating. These traps can be used for draining condensate from steam water and oil heaters, blast heaters, unit heaters, dryers, vulcanizers, kitchen equipment, laundry equipment, evaporators, steam lines and other equipment, where the pressure differential between Bteam supply and condensate return does not drop below 5 psi. Flash type traps are made in sizes . from i 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 tne flashing action lift the condensate out of the bucket to the return opening. Upright bucket traps are used for draining condensate and air from blast coils, unit heaters, steam mains, laundry 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 hot influenced by pulsations or wide fluctuations of pressure. Upright Ducket trapB are obtainable in sizes varying from J 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 buoyancy. The steam pressure entering through the open, valve discharges the trap. Air is eliminated automatically by passing through the small vent hole located in the top of the inverted bucket. Inverted bucket traps for use on low pressure systems, par ticularly with blast coils or unit heaters, are usually furnished with a large capacity opening equipped with a bi-metallic thermostatic element which closes when heated " by steam, and opens when cooled by air and condensate, allowing air to escape from the inverted bucket to the trap outlet. Inverted bucket traps are used for draining condensate and air from blast coils, unit heaters, steam drips, laundry equipment, sterilizers, steam water heaters and other equipment. They are particularly suited for draining condensate from steam lines or equipment where abnormal amounts of air must be discharged, and where there is also foreign matter such as dirt, sludge and oil draining to the trap. The discharge from inverted bucket traps, like that of the upright bucket traps, is intermittent and requires a definite differential pressure between the inlet and the outlet of the trap in order to lift the condensate from the Fig. 31. Tilting Tbap 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 flow, 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. . When condensate reaches near-steam temperature, part of the control flow flashes into vapor, due to reduced pressure in control chamber. The increased volume of the 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. Under 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 J to 2 in., and for pressures ranging from one to 600 psig. Fig. 30 illustrates a trap of the impulse type. Tilting Traps. This type of trap as the name implies depends for its operation on the tilting of the trap receiver. When the receiver is in a horizontal position con densate accumulates until the weight of condensate overbalances that of a counter weight, when the receiver tilts. The tilting action opens the discharge valve, and steam pressure pushes the condensate out of the open discharge valve. When the. receiver tank is emptied, except for a slight water seal, the receiver drops back to itB 504 CHAPTER 20 1952 Guide Steam Heating Systems 505 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 accumu 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 Sow 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 Trap. 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 sizes 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 diy.. 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 1} 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. . .. Steam Trap Installations ' The following general rules 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 Beak Fig. 36. Looping Dry Return Main Around Opening Fig. 37. Methods of Taking Branch from Main ' ' To find length C-tnuJUply A by constant for ange 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 ofi 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 steam 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 STEAM MAIN Fig. 40. Dripping End of Main into Wet Return OR! RETURN MAIN DIRT POCKET Fig. 41. Dripping End of Steam Main into Dry Return Fig. 42. Dripping Heel of Riser into Dry Return 506 CHAPTER 20 1952.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 Steam Heating Systems |jj_ /Runout above floot ^"fi,ser/ Wallljne^ o^Swing^^H nii!iinminiiniiiij|iiiUTT| 1 Radiator X i"n* 'vl Runout below floor PLAN 507 Fig. 43. Flash Leg Installation for 80 psi Maximum Steam Working Pressure Table 13. Dimensions Applying to Fig. 43 Traps Con- PEB HE., Lb at 70 Psi ! 200 . 300 ' 700 1500 2500 4000 8000 15000 HP Side N m & (S K6 A is cu LP Side c .C2O & o. is CL 6 0- Flash 2 i t 21-80 A 31-7C '3 a 0-20 4 0-15 4 f 31-7C 1 i 0-15 4 1 61-8C i i 0-15 5 l 61-8C li 10-15 8 U H 61-8C 2 1* 0-15 10 2 61-80 21 1*0-15- 12 24 A 61-80 \2i 1*0-15 16 Ft. 3 3 3 4 5 6 6 6 - B c D E F l_G In. In. In. In. In. In. 68 68 68 6 10 6 10 6 12 6 12 8 14 3 3 - i24 ii u a 4 1 3 4 - 124 H U 1 1 41 2 H 5 H 24 4 52 3 2 63 3 3 Plate NESS. In. i i i 1 i i i 1 Fig. 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 flash tank or flash leg into which the high pressure trap is arranged to discharge. This tank provides the required space for the flashing from high temperature condensate to low pressure 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, Fig. 45. Two-Pipe Top and Bottom Fig. 46. Two-Pipe Connections to Opposite End Radiator Connections Radiator Hung on Wall 508 CHAPTER 20 / 1952 Guide THERMOSTATIC TRAP, .INCET VAiVE Pig. 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 property 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. - -Two methods of-connecting a unit heater to a one-pipe steam heating system are* illustrated in Fig; 2 (and also in Fig. 5 of Chapter 24). Steam Heating Systems 509 Fig. 51. Typical Connections to Finned Tube Blast Heating Coils of the Steam Distributing or Non-Freeze Type ;Typical;two-pipe radiator connections are shown in- 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 a typical return and connection for blastheaters 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 Air Fig. 52. Typical Return Connections to Finned Tube Blast Heaters with High Pressure Steam . 510 CHAPTER 20. -SUPPUr MAIN 1952 Guide fob 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.E1 Research Report No. 951--:Condensat-e and Air Return in Steam Heating Systems, by F. C. Houghten and- J. L. Blackshaw (A.S.H.V.E. Transac tions, Vol. 39, 1933, p. 199). 1 Pipe size tables in this chapter 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. ' * A.S.H.V.E. Standard Code for Testing and Rating Return Line Low Vaeiium Heating Pumps (A.S.H.V.E. Transactions, Vol. 40, 1934, p. 33). - CHAPTER 21 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 ' Twc^Pipe Forced Circulation Systems, Expansion Tanks, Installation Details, Zoning of Systems AHEATING 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 23) 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 48). AVAILABLE CIRCULATION HEAD The available head in a gravity circulation system may be.found from the equation: . : a- - A. = ^-r X 2.31 X 12,000 144 (1) where . A. = available head per foot of height, milinches (1 milinch = 1/1000 ofTin. 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 flow temperature of 200 F and a 35 deg drop, and with the mains located 4 ft above the center line of the boiler, the available head is 600 milinches. This is found by following the 200 F flow riser line in Fig. 1 to its intersec tion with the 165 F return riser line, and then reading, horizontally, a head 511 512 CHAPTER 21 1952 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 513 Table 1. Iron and Copper Elbow Equivalents* Fitting Iron Pipe Copper Tubing Fitting Iron COPPBB Pipe Tubing Elbow, 45-deg.............. ........ Elbow, 90-deg long turn___ Elbow, welded, 90-deg......... Reduced coupling................ Open return bend................ 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 2.0 Radiator or convector.... 3.0 Boiler or heater................. 3.0 Tee, per cent flowing through branch: 100 ...................................................... 50................................ 25......................... . .. 1.8 4.0 16.0 3.0 4.0 4.0 1.2 4.0 20.0 ' * The friction in one 00 deg standard elbow is approximately equal to the friction of a length of straight pipe of the same nominal sue and 25 diam long. Hence, one elbow equivalent in feet of pipe equals 25 diam (in inches) divided by 12. 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 system, 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 heat ing system must be known in order to design either gravity or forced circu lation systems. The friction loss of fittings is customarily expressed in equiv- 514 CHAPTER 21 1952 Guide Table 2. Heat-Gabbying Capacity of Standard Black Pipes with Tempebatuhe Drop of 20 Deg* Nominal Pipe Sizes % in. to IS in., and Friction 4 to 800 milinches per foot (A = Capacity, Mbh. B = Velocity, inches per second) (One milinch equals 0.001 in.) MCLINCH FaiCFoot-op Pipe M H H Nominal Pipe Size,, Inches 1H m 2 2H 3 3H 4 5 6 8 10 12 4 A 0.75 1.35 2.85 5.4 11.3 17.0 33.0 53.1 95 141 197 363 596 1250 2320 3730 B 1.5 1.7 2.1 2.4 2.9 3.2 3.8 4.3 5.0 5.5 6.0 7.0 7.9 9.6 11 12 6 A 0.9 1.7 3.6 6.75 14.0 21.2 41.3 66.4 119 176 248 456 748 1570 2920 4690 B 1.8 2.1 2.6 3.0 3.6 4.0 4.7 5.3 6.2 6.9 7.5 8.8 10 12 14 16 8 A . 1.05 2.0 4.2 7.9 16.4 24.8 48.4 77.9 140 207 291 535 879 1850 3440 5520 B 2.1 2.5 3.0 3.5 4.2 4.7 5.6 6.3 7.3 8.0 8.8 10 12 14 17 19 10 A 1.2 2.2 4.7 8.9 18.6 28.0 54.7 88.1 158 234 329 605 997 2100 3910 6270 B 2.4 2.8 3.4 4.0 4.8 5.3 6.3 7.1 8.2 9.1 9.9 12 13 16 19 27 12 A 1.35 2.45 5.2 9.8 20.5 31.0 60.4 97.4 175 259 364 671 1100 .2320 4330 6950 B 2.7 3.1 . 3.7 . 4:4 ,5.3 5.9 6.9 7.8 9.1 10 11 . 13 15 18 21 24 14 A 1.45 2.65 5.65 10:7 22.3 33.7 65.8 106 190 282 397 731 1200 2530 4730 7590 B 2.9 3.4 4.1 4.8 5.7 6.4 7.6 8.5 9.9 n 12 14 16 20 23 26 16 A 1.55 2.85 6.05 11.5 24.0 36.3 70.8 114 205 303 428 787 1300 2730 5100 8190 B - 3.1 3.6 4-4 5.1 6.2 6.9 8.1 9.7 11 12 13 .15 17 21 25 28 20 A 1.75 3.25 6.85 13.0 27.1 41.0 80.0 129 232 344 484 892 1470 3100 5790 93C0 B 3.5 4.1 4.9 5.8 7.0 7.7 9.2 10 12 13 15 17 20 24 28 32 25 . A 2.0 3.65 7.75 14.7 30.6 46.3 90,5 146 263 389 548 1010 1670 3510 6570 10560 B 4.0 4.6 5.6 6.5 7.9 8.8 . 10 12 14 15 17 19 22 27 32 36 30 ' A B 2.2 4.0 8.55 16.2 33.8 51.2 100 162 290 430 607 1120 1850 3900 7280 11710 4.4 5.1 6.1 7.2 8.7 9.7 11 13 15 17 - 18 . 22 25 30 35 40 35 A 2.35 4.4 9.3 17.6 36.8 55.7 109 176 316 469 661 1220 2010 4250 7940 12780 B 4.7 5.5 6.7 7.9 9.5 11 13 14 16 18 20 23 . 27 33 39 44 40 A 2.55 4.7 10.0 18.9 39.6 59.9 117 189 341 505 712 1320 2170 4580 8570 13780 B 5.1 5.9 . 7.2 8.4 - 10 11 13 15 18 20 22 25 29 35 ' 42 47 50 A .2.85 5.3 11.3 21.4 44.7 67.7 133 214 386 572 807 1490 2460 5190 9720 15650 B 5.7 6.7 8.1 9.5 12 . 13 15 17 20 22 24 29 33 40 47 54 60 A B 3.15 5.85 12.4 23.6 49.4 74.9 147 238 427 633 893 1650 2730 5760 10780 17360 6.3 7.4 8.9 11 13 14 17 19 22 25 27 32 36 44 52 60 B70 A 3.45 6.35 13.5 25.7 53.8 81.4 160 258 ` 465 690 973 1800 2970 6280 11760 18950 6.9 8.0 9.7 11 14 15 18 21 24 27 29 35 40 ' 48 57 65 80., A B 3.7 6.8 14.5 27.6 57.9 87.6 172 278 500 743 1050 1940 3200 6770 12690 20440 7.4 8.6 10 12 . 15 17 20 22 26 29 32 37 43 52 62 70 100- A' ' 4.15 7.7 16.4 31.1 65.4 99.0 194 314 566 840 1190 2200 .3630 7680 14400 23200 -B 8.3 9.7 12 14 17 19 22 . 25 30 .33 36 42 48 59 70 80 . 150 A 'B 5:2 9.6 20.4 38.8 81.6 124 243 393 709 1050 1490 2760 4560 9650 18120 29220 10 12 15 17 21 23 28 32 37 41 45 53 61 74 88 101 ' 200. .A ' 6.05 11.2 23.9 45.4 95.5 145 285 461 832 1240 1750 3240 5360 11350 21320 34400 B 12 14 . 17 20 25 27 33 .37 43 48 53 62 71 87 104 118 300 ' A ' B 7.5 13.9 29.7 56.6 119 181 356 577 1040 1550 2190 4060 6730 14270 26830 43300 15 18 21 25 31 34 41 46 54 . 60 66 78 90 110 131 149 400 . .A 1 ;. B .8.75 16.2 .34.7 66.2 140 212 417 676 1220 1820 2570 4780 7910 16790 31580 51000 18 .21 26 30 36 40 48 54 64 71 78 92 105 129 . 154 175 500 A 9^85 18.3 39.2 74.8 158 239 471 ` 765 1380 2060 2910 5410 8970 19040 35840 57880 ) B . .20 23 29 33 41 45 54 62 72 80 88 104 119 147 174 199 600 A 10.9 20.2 43.2 82.5 174 264 521 846 1530 2280 3220 5990 9930 21100 39740 64210 B 22 26 32 37 45 50 60 68 80 89 97 115 132 162 193 221 800 A 12.7 23.6 50.6 96.5 204 310 610 992 1790 2670 3780 7030 11670 24820 46780 75620 B 25 30 37 43 52 59 70 80 94 104 114 135 155 191 228 260 * For other temperature drops the pipe' capacities may be chanced correspondingly. For example, with - a temperature drop of 30 deg. the capacities shown in this table are to be multiplied by 1.5. , - If! f-r jL Hot Water Heating Systems 515 alent number of elbows of the same pipe size which would hive 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 1. 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 WATER IN GALLONS PER MINUTE 40 60 100 200 Z * * e 10 20 30 40 o eo no 200 400 goo 1000 2000 HEAT CONVEYED PER HOUR IN THOUSANDS OF BTU Fig. 3. Friction in Type L Copper Tubing 5000 Lower scale of chart is based on 20 deg temperature difference between flow and return risen. To find friction when temperature drop is other than 20 deg, multiply the actual heat conveyed by factual temp, drop, I 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 reversal return systems are shown in Figs. 4, 5, and 6, re- 516 CHAPTER 21 1952 Guide L' Table 3. Heat-carrying Capacity of Type Copper Tubing . : with. Temperature Drop of 20 Deg* . Nominal Tube Sizes | in. to 4 in., and Friction 60 to 720 milinches per foot. (A = Capacity, Mbh. B = Velocity, inches per second) (One milinch equals 0.001 in.) . Nominal Tube Size In. 720 . Milinch Fkiction Loss peb Foot of Tube 600 < 480 360 300 240 180 . 150 120 90. .75 ,60 ' A'1* ' 10 9 .. B 27. 24 .A H . J? A' %B 20 . 18 35 30 36 30 37 34 A' HB 51 46 42 . 38 A 104 94 ^ 1 B 48 45 . A 1H B 185 169 55 51 - A 300 270 B 62 57.- A -` 625 / 560 2 B . 76 68 A . '1130) 1010 :2H b ; 90 - 80 A ' 1840 1650 3 B 98 90 .A 3H B 2750 2480 110. 100 A 3900 3505 4 .B 120 108 8 6.8 6.2 21 18 16.5 5.4 4.6 : 14 13 4 11 16 13.5 12 10.8 9 8 25 21 19 17 15 13 26 22.1 . 20 17.8 30 24 21 19 15. 13.1 17 15 40' 34 ' 31 33 27 24 28 ' 23.2 20.5 21 19 17 82 70 39 ' 34 63 ... 56 . 47 i 42 30 25' 22 19 149 125 112 100 84 75 45 39 35 30 25 22 235 200 180 160 134 120 51 43 39. 35 30 25 .495 420 375 335- '-280 250 59 51 47 42-; 36 32 890 750 : 680 600 ' V500 69 58 49. 47 42 450 37 1450 1210 1100 980 80 66 59 ' 52 820 740 47- 42 2170 1840 1650 1450 1210 1100 89 75 66 57 51 . `45' 3100 2600 2350 : 2090 1760 1580 96 83 73 .63 55. 49 3.6 3 2.8- 2.4 10 8.5 * 8 7 -7 6 5.4 4.7 12 10 9 8 11.8 9.9 9 7.9 13 11 10 ' 9 18.1 15:3 13:9 12.1 14 12 11.5 10 37 32 17 14.5 28 25 13. 12 66 56 50 44 19 17 16 13 105 90 22 . 19 200 188 27 22 . 81 71 17 ... 15 170 150 20 : 18- 395 335 ' 305 33 26 23 270 21' 650 550 490 420 36 30 27 23 980 820 . 740 650 40: 35 ; 30 26. 1390' 1180 1080 44 37.. 34 950 29 ; a For other temperature drops the pipe capacities may be changed correspondingly, For example,-with 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. , . Oner-pipe forced systems compared with gravity systems provide more rapid'circulation, with consequent smaller1 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 FiPiR f 4.Fig. One-Pipe System Fig. 5. A Two-Pipe Direct Return System . AFig. 6 Two-Pipe Reversed Return System Hot Water Heating Systems 517 Table 4'.'. Friction (in Milinches) of Central Circular , Diaphragm Orifices in Unions (One milinch equals 0.001 in.) . . DiunrsB or Orifices (Inchsb) 1 2 , .. . Vaocm oi Water in Pub in Ihches fer S*com> . ` '' | -3 |(; 4 | .6 V. . |8 10 %-in. Pipe. j .| . 12. 18 . 24 1 34 0.25 0.30 0.35 : 0.40 , 0.45 0.50 0.55 1300 650 330 170 2900 1450 740 380 185 5000 2500 1300 660 330 155 75 11,300 20,800 32,000 45,000 5700 10,400 16,000 23,000 57,000 ,2900 5200 . 8000 12,000 26,000 1500 2600 ; 4000 6800: 13,000 ;740 -1300 2000 2900 6500 . 350. 620 970 1400 3200 170 300 480 700 1600 47,000 24,000 53,000 12,000 27,000 5700 13,000 2800 6400 0,35 0.40 0.45 0.50 0.55 0.60 0.65 900 2000 3500 460 1000 1800 270 570 1000 160 330 580 190 330 200 120 1-in. Pipe 7800 14,000 22,000 4000 7200 .12,000 2300 . 4100, ... 6400 1400 ` 2300 .. 3700 750 1300 2200 440. . . 800 13Q0 260 460 720 32,000 17,000 9300 5400 3000 1800 1100 37,000 65,000 21,000 37,000 12,000 22,000 50,000 7000 13,000 28,000 "4200' 7400 17,000 2400 4300 10,000 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 lVfin. Pipe. 8900 5800 3800 2500 1700 1150 750 16,000 10,400 6800 4400 3000 2000 1300 25,000 36,000 16,400 23,000 10,500 15,000 .6900 10,000 4700" 1 6700 3100 , 4500 2100 3000 53,000 34,000 22,000 15,000 10,000 6700 60,000 40,000 27,000 60,000 18,000 40,000 12,000 26^000 0.55 0.60 0.65 0.70 0.75 0.80 0.85 I'A-in. Pipe 850 1900 3300 7400 13,000 21,000 30,000 600 1300 2300 5400 8600 16,800 2i;ooo 50,000 400 850 1500 3600 7200 10,400 14,000 30,000 53,000 260 600 1100 2600 4400 7000 10,000 21,000 39,000 180 400 760 1800 3000 5000' 7000 14,000 28,000 300 540 . 1200 2200 . 3200 : 5000 10,200 19,000 45,000 200 380 860 1600 2300 3000 7800 13,000 30,000 0.70 0.80 0.90 1.00 1.10 1.20 1.30 890 1850 3500 470 975 1800 255 560 1000 160 340 610 214 375 195 S-in. Pipe 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 7900 4200 3100 ;` i . 38,000 23,000 49,000 14,000 30,000 8100 16,800 4400 8850 Wote.--The losses of head tor the orifices In the lK-in. and 2-in. pipe were calculated from those in the smaller pipes, the calculations being .based on the assumption that, for any.given velocity, the loss of head ts a function of the ratio of the diameter of the pipe to that of the orifice. ' This had been found to be practically true in the tests to determine the losses of head in orifices in 3-in..;l-in..-and*l}4-in. pipe, con* ducted by the Texas Engineering Experiment Station, and also in the tests to determine the losses of bead hnhoes in 4-in., 6-in., and 12-in. pipe, conducted by the Engineering Experiment Station of the University of Illinois. {Bulletin 109. Table 6. p. 38. Davis and Jordan). 518 CHAPTER 21 1952 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 Phtoc Amancemknt One-Pipe Two-Pipe Direct Return Two-Pipe Reversed Return . Type op Circulation Gravity Forced . Gravity Forced Gravity ' Forced Expansion Tank . Open Closed . ;Open . Closed Open - Closed Open Closed Open Open Closed -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 are likely to cause disturb ing noises in buildings other than factories: 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 the 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 519 The water to be, circulated is W = ff/(C41) (2) where . W = weight of water, pounds per hour [gallons per minute = W/{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- Iation system is diagrammed in Fig. 8.. . ` . . ' ! ! ; Fio. 7. Gravity System Fig. 8. Forced Cir culation System Fig. 9. Determina tion of Required ' Temperature Difference Elementary Gravity System " : 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 un'.r' i ^bis uniform velocity is such that the friction of the circuit is equal to the a l "eYelPed by *be 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 n5ers> respectively, the head will be 90 milinches per foot of water column. A, 8 "e?d urey be found from Fig. 1. Since the center of the radiator is 10 ft above tne 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. ine friction of 1 ft of 1 in. pipe is found from Fig. 2 to be about 46 milinches at 20 Mon, and the corresponding velocity 9 in. per second. Note that all values in Fig. z are based on a temperature difference of 20 deg. . Similarly, if a 11 in. pipe were to be used, the frictionhead would be about 12 mil- inches per foot, and the corresponding velocity about 5 in. per second, from Fig. 2. (>T0 bp1*2t3be4 5friction in the elbows, boiler, radiator, and valve, Table 1 is used, and Liu6 Clrcu!t *s found to be equal to 10 elbow-equivalents plus 24 ft of pipe. 'tl= elbow-equivalent is equal to a pipe length of 25 times the nominal diameter. -~n t6 e9uivalent lengths of straight pipe are 45 ft of 1 in. pipe or 50 ft of 1J in. PP;, . 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- 520, CHAPTER 21 , .. . 1952 Guide inches, and if 11 in. pipe is used, the friction will be 50 X12, or 60Q 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 11 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 to 160 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 bn 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 or 585 milinches. Since the head wpuld.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 i System (Example 3) System (Example 4) flow riser temperature is 200, the return riser temperature will be HO, and the average water temperature in the radiator about 185 F. '' Elementary Forced Circulation System ; ; Example 2: Design a system for the piping arrangement shown in Fig. 8, accord ing to 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 must develop. Solution.- Assume 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 will 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, tod 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 tor about 197.5 F. . If a ) in. pipe were.used instead of a 1 in., the equivalent length of circuit would be 35 ft instead of 45; the unit head, 686 milinches instead of 533; the velocity, 27 in. per Hot Water Heating Systems 521 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,(MM) 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 100 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 f in.); the equiva lent length is therefore 33 ft. The circuit can therefore be designed for a friction loss of 504 t- 33 = 15 milinches per foot. From Table 2 by interpolation a I 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 made 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 -- n/wi \ (gy qqq X 30J = 186 F. 30) = 181 F. - .. . /QftOfl 4- 10 SOD At point F the temperature will be 190 -- (----- 7 400'-- X One-Pipe Forced Circulation System Example 4- Select pipe sizes for the one-pipe forced circulation system having a load of 67,500 Btu shown in Fig. 11. Assume a water temperature drop of 20 deg. The water temperature does not affect the size of piping, but does affect the radiator sizes required. Solution: The water to be circulated at 20 deg drop will be 67,500 + 20 - 3375 lb per hour or = 7 gpm. By reference to manufacturers' pump capacity charts (typical example, Fig. 12), 522 CHAPTER 21 1952 Guide -it will 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 O 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 11 in. pipe would supply 131,600. Since the 1 in. pipe is too small, a 1} in. pipe will be used. Since the 1} 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 Toss 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 Fig. 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 -s- 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 6: Select pipe sizes for the two-pipe gravity system shown in Fig. 13. The center plane Of the nighest 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 118 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 + H:N containing 38 ft of pipe and, if 50 percent is added for equivalent length of fittings, the equivalent length is 57 ft. . Hot Water Heating Systems 523 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 Bize corresponding to 20/30 of actual load for each section as follows: , Section Load Mbh Size op Pipe fob 16 Milinches peb Foot ' Section A-B B-C C-D D-E E-F . 58 31 20 16 6 m G-H 1H H-K IH. K-L 1 L-M H M-N Load Mbh Size op Pipe pob 16 Milinches peb Foot 11 19 25 31 58 1 1H 1H 1*4 . Piping to the radiators may be sized from Table 2 for the same resistance, 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: Radiator.......................................... FI . F2 #3 F4 #5 Load. Mbh................ ..................... 11 8 8 6 24 Pipe sise. In........................................ 1 '4 ` * 1- 1 11 F6 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. ' 7950 Solution: The water to be circulated is 159,000 -5- 20 = 7950 lb per hr or ^ g 16.5 gpm. From a pump performance chart such as Fig. 12 it is found that 16.5 gpm will be delivered by a 1 in. pump against a 3 ft head (36,000 milinches) or a li in. 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 li 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 SOPPLT Mbh 159 91 75 63 49 37 16 ' Pipe Size, In. ' Section IH J-K 1H K-L IH L-M 1M M-N 1 . N-O 1 O-P H P-Q Retubn Mbb Pipe Size, In. 16 . 28 42 54 75 91 . 159 H H .1 ,,1 1M IH m The radiator circuits may also be sized for the same friction loss, 300 milinches per foot, using Table 2 as follows: Radiator........ ...................................... *1 2 *3 <4 Load, Mbh........................................ 18 12 14 12 Pipe site. In.......................................... | 4 4 4 0 Where circuit divides, use } in. branch to F5 and 4 in. to F6 radiator. *5 and *6 *7 21 16 I 524 CHAPTER 21 1952 Guide It M8H Fig. 13. Two-Pipe Revebsed Return Gravity System (Example 5) Fig. 14. Forced Circulation Two-Pipe Reversed Return System 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 ENT GAGE/"* GLASS OVERFLOW PIPE EXPANSION PIPE CIRCULATING TO INSIDE SEWER PIPE DRAIN Fig. 15. An Open Expansion Tank Fig. 16. A Closed Expansion tank Hot Water Heating Systems 525 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 A .S.MJS. 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 dosed expansion tank 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, + 0.434R P, 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. H -- 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 containing 5000 gal and operating at 200 F flow temperature. The static head, due to the 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 526 CHAPTER 21 1952 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, V= 200 14.7 200 = 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. Table 6. Required A.S.M.E. Size of Closed Expansion Tank Sq Ft op Equivalent Direct Radiation Installed Gallon Tank - Sq Ft op 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 1600 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 33sq 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. 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 AJSM.E. 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 527 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 Water in Standard Pipe Pipe Size, In. H M 1Itt Lineal Ft op Pipe Containing 1 Gal 63.1 36.1 22.2 12JS 9.47 Pipe Size, In. 2 2H 3 4 6 6 Lineal FT op Pipe Containing 1 Gal 6.76 4.02 .2.60 1.52 0.96 0.67 run around an obstacle 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 1 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 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 circula- 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 in 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. . yuPPly connections are usually made at the bottom of radiators so that circulation ui not be stopped by accumulation of air, as would be the case with a top supply 528 CHAPTER 21 1952 Guide Fig. 17. Vertical Zoning of Hot Water Heating System in a 12-Story Building 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 used. ' Unless used as heating surface, all piping, both flow and return, should be insu lated. All large systems should be provided with extra stop and drain valves, suitably located so that parts, of the system may be isolated for repairs without making it necessary to drain the water from the entire system. - Relief Value. The A.S.M.E. 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 hori zontal) 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 22 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 typd. 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 emission 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): 530 CHAPTER 22 1952 Guide Table 1. Column-Type Cast-Ibon Radiator Height Inches 15 18 20 22 23 26 32 38 45 Generally Accepted Rating peb Section* One Column ' Sq Ft ' Btu/hr TwoCoIumn . Sq Ft Btu/hr Three.Column ` Sq Ft Btu/hr i*4 . m 2 2*4 3 360 ' 400 480 600 720 1*6 360 2' 480 2*4 ' ' 540 2*6 . 560 2H 640 3*6 800 4 660 5 1200 . 540 3 720 3* 600 4*6 1080 5 1200 6 1440 Four Column ' ` Five'Column Six column -- . . Sq Ft Btu/hr 13 16 . 18 20 22 , 26 -.32 38 45 - 3 4 5 6*6 8 10 720 -. . 660 1200 . 1560 1920 2400 - .Sq Ft - 4*4 < 7 10 Btu/hr Sq Ft . Btu/hr . 1120 * 1680 2400 3 3*4 . 4*4 r- 5r 720 900 1080 1200 t These ratings are based on steam at 215 F and air at 70 ' F. They Apply only to installed radia* tore exposed in a normal manner; not to radiators installed behind enclosures, grilles, or under shelves. For Btu per hour ratings at other temperatures, divide table values by factors found in Table 6. Table 2. Labge-Tube Cast-Iron Radiators Sectional, cast-iron, tubular-type radiators of the large-tube pattern, that is, having tubes approximately 11 in. in diameter, 21 in. on centers. - -- Number op Tubes peb Section ' Catalog Rating per Section* Sq Ft Btu/hr Height ' In. Width Section Center, Spacing1* Leg Height6 To Tapping In. . '(In. In. T i* 420 20 2*6 4*6 2 480 ' 23 2*6 4*6 3 2*4 560 26 4*6 2*4 :4*6- 3 720 32 2*4 4*6 3*4 840 38 2*4 4*4 2*4 - 540 - 20 4 . -2*4 600 23 2*6 ` ' 4*6 2*4 660 26 6*4-6Me 2*6 4*6 . 3*4 840 32 2*6 4*6 4*4 1020 38 2*4 ; 4*4 2H 640 `20 3 720 23 5 3*4 840 26 4*4 * 1040 32 5 1200 38 2*4j " 2*4** 2*4*! 2*4;* 1 2*4*1 4*6 4*6 4*6 4*6 4*4 3 '720 20 2*6 . 4*6 . 3*4 840 23 2*6 - 4*6 - 6 4 660 26 9-10*6 2*4 4*6 5 1200 32 2*6 4*6 6 1440 38 2*4 4*4 . 2*4 600 14 . 2*6 3 7 3 720 17 11*6-12>M 2*4 3 3% 880 20 2*4 3 or 4*6 * These ratings are baaed on steam at .215 F and air at 70 F. They apply only to installed radia tors exposed in a normal manner; not to radiators installed behind enclosures, grilles, or under shelves. For Btu per hour ratings at other temperatures, divide table values by factors found in Table 6. D Maximum assembly 60 sections. Length equals number of sections times 21 in.- c Where greater than standard leg heights are required, this dimension shall be 6 in., except for 7-tube sections, in heights from' 13 to 20 in., inclusive, for which this dimension h*11 be 41 in. ` Radiators may be furnished without legs. . . d For 5-tube hospital-type radiation, this dimension is 3 in. Radiators and Convectors 531 Number op Tubes per Section , Table 3. Small-Tube Cast-Ibon Radiators '- Catalog Rating per . Section* Section Dimensions . A Height6 B Width Minimum Maximum c. Spacing1* D Leg Height0. Sq Ft Btu/hr - In. In. - In. In. In. 3d . 4d 5d 6d 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 25 19 -22. ' 25 22 25 19 25 32 3*4 . 4*4, ^ 4M 4Mo 554 5*6 6'Me ' 6*M 61*0 3*4 41*6 41*6 41*6 6*6 6*6 8^ 8 8 1* w 1* m 1*4 154 154-. m 1*4 2*4 2*6 2*6 2*4 2*4. 2*4 2*4 2*4 2*4 t) &. mm a These ratings are based on steam at 215 F and-air at 70 F. They apply only to installed radia tors exposed in a normal manner;-not to radiators installed behind enclosures, grilles,-or under shelves. For Btu per hour ratings at other temperatures, divide table values by factors found in Table 6. b Length equals number of sections times 11 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 shall be 41 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 Height 13*4 13*4 22 13*4 29 Length or Width 16*6 22 13*4 29 13*4 . Thickness 3 3 3 3 3 Heat Output Sq Ft 6*4 8 8 11 11 Btu/hr 1560 1920 1920 2640 2640 * These ratings are based on steam at 215 F and air at 70 F. They apply only to installed radia tors exposed in a normal manner, not to radiators installed behind enclosures, grilles, or under shelves. For Btu per hour ratings at other temperatures divide table values by factors found in Table 6. 532 CHAPTER 22 1952 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- Table 5: Heat Emission op Pipe Coils Placed Vertically on a Wall (Pipes Horizontal) Containing Steam at 215 F and Surrounded . with Air at 70 F Btu per linear foot of coil per hour (not linear feet of pipe) Size of Pipe Single row................................................ Two. .. v............. i Four............ ............................ ........... Six............................................................... Eight.......................................................... Ten .......... ..........'....v.................... Twelve.............................______________ 1 In. ' 132 252 440 567 651 732 812 HIn. 162 312 545 702 796 907 10)5 . 11 In. 185 348 616 793 907 1020 1135 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 whieh 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.* 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 533 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 the pipe. _ The heat emission of pipe coils placed vertically on 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 175 Btu per linear foot of pipe, respectively, for 1-in., 11-in., and 11-in. coils. . . *. 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 Metal front Fig. 1. Typical Recessed Convectob Plaster front 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 and the grilles be so designed that they will not 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 appearance. 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 534 CIHA' PTER 22 1952 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 pier 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.' 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 In. Hg. Abe Lb per Sq In. Heating Factors for Direct Cast-Iron Radiators Factors for Convectors . Temp F Steam on Wateb Room Temperature F 80 75 70 65 60 55 50 Inlet Air Temperature F 80 75 70 65 60 55 50 22.4 20.3 17.7 14.6 10.9 6.5 Lb per Sq In. 1 6 15 27 52 3.7 4.7 6.0 7.6 9.3 11.5 15.6 21 30 42 67 150 160 .. 170 180 190 200 215 230 250 270 300 2.58 2.36 2.17 2.00 1.86 1.73 1.62 3.14 2.83 2.57 2.35 2.15 1.98 1.84 2.17 2.00 1.86 1.73 1.62 1.52 1.44 2.57 2.35 2.15 1.98 1.84 1.71 1.59 1.86 1.73 1.62 1.52 1.44 1.35 1.28 2.15 1.98 1.94 1.7*1 1.59 1.49 1.40. 1.62 1.52 1.44 1.35 1.28 1.21 1.15 1.84 1.71 1.59 1.49 1.40 1.32 1.24 1.44 1.35 1.28 1.21 1.15 1.10 1.05 1.59 1.49 1.40 1.32 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 1.00 1.10 1.05 1.00 0.96 0.92 0.88 0.85 1.17 1.11 1.05 1.00 0.95 0.91 0.87 0.96 0.92 0.88 0.85 0.81 o.ya 0.76 1.00 0.95 0.91 0.87 0.83 0.79 0.76 0.81 0.78 0.76 0.73 0.70 0.68 0.66 0.83 0.79 0.76 0.73 0.70 0.68 0.65 0.70 0.68 0.66 0.64 0.62 0.60 0.58 0.70 0.68 0.65 0.63 0.60 0.58 0.56 0.58 0.57 0.55 0.53 0.52 0.51 0.49 0.56 0.54 0.53 0.51 0.49 0.48 0.47 * To determine the size of a radiator or a convector for a given space, multiply the heat loss of the space in Btu per hour by the proper factor from the above table and select radiator or convector having an equiva lent Btu per hour rating. ' ' ,, ' An alternate method is 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. s 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 65 F in the case of a convector, divide the heating capacity at the basic rating 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,4 (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 535 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 -t-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 be addressed to the Division of Trade Standards. . A Testing and Rating Code for Baseboard Type of Radiation5 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 pier 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 I = B = R Steam Ratings: (1) rating in Btu pier hour pier 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 I = B = R Water Ratings: (1) rating in Btu per hour pier linear foot for each average water tempera ture listed, (2) percentage added to capacity in deteimining 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 Manufacturers. ' Effect of Operating Conditions . The heat output of a radiator is proportional to the 1.3 power of the tempierature 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 536 CHAPTER 22 1952 Guide Table 7. ' . Factors to Convert 7 = B = R Steam Ratings to Hot Water . Ratings at Temperatures Indicated Average Radiator Temperature ' Factor Average Radiator ' Temperature ` Factor ' '"Average Radiator Temperature v Factor 150 , 155 160 165 170 0.45 0.49 . 0.53 0.57 0.61 175 0.65 180 0.69 185 0.73 190 0.78 195 0.82 200 205 ' 210 . 215 220 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 rating- test 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 The output under standard conditions will be: where //. - CJh C. = correction factor. . . . ' t, = steam temperature during test, Fahrenheit degrees. ' tT = room temperature during test, Fahrenheit degrees, tj = inlet air temperature during test, Fahrenheit degrees. H, = heat emission rating under standard conditions, Btu per hour. H. = 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.8-910 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 537 temperatures.12-18 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 radia1 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 It 1 1 1 1 1 1 ! i 1 Temperature m deg F .wMoroomtempino^r Position Na 3 ftjsition Na 1 t Ml 11111 30-level Eaun Diff 30* level Eauiv Dirt 13 5.60 lb convector Na 1 16 * r7rf,fr z ^tttt* 5-84 ^ convector No. 72 67.7 662 15 674 659 1JS ftB 9 642 3S -22 m 4M'i m lH|lH1111 converter Na 6 6&0 66.6 1.4 6&0 6S.1 *23 67.9 ao 682 66.4 13 0 123456789 10 Equivalent net steam condensed, fb per Hour r- ------- -|-- ~[----------------: Test I-W74, convector Na 6 **|-- ------- == -- = = =^LenRth3tr, ? blocked = == = Test l-W4, convector Na 22= --1 ] -- rj 2r. L[L* Cf, = = =|= =tength32-.-J -j j ] =E= = Cotrtvech Na 22 Djnvector Na 1 non-t errous cast iron testirigunit testing unit --= ------- --|-- --\y!d -- Test I-W10L convector Nat _ -- Length37l*. 3-se<^ blocked 4 j~ p -v Eftfc =J:Test R-W64.8-sec, 26', 5-tube radiator,: = 18El J! J in -- = -- --5 3== = - lj^4C MHBl = -- r =^ ~ I Jzz = H ~| ^ [ 1 ~t 1 '----* -- \ 1 " t ~ -- - Steam tamo 216.5* f z " Z ~ 1 fbt------- ----| j - J -- ~f | 1 ; __ g _ 5-tt be cas iron rad afar --I--*-- Ccmvector Na 6 non-ferrous heating un3 . 10123456789 HEIGHT ABOVE ElOOR IN FEET Fig. 2. Temperature Gradients and Equivalent Temperatures for Radiator 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,16 the thermo-integrator,18-17 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 show 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 in the test room. The difference between the minimum and the maximum 638 CHAPTER 22 1952 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 2i5 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. Radiators and Convectors 539 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. There should be better 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- 4 56 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 breathing level. 4. The comfort 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. Tests19 on an old-style column-type cast-iron radiator indited 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 Fig. 4. Steam. Consumption of Exposed and Concealed Radiators ator with a well-designed enclosure (B), with a poorly-designed enclosure (C), and with a cloth cover (D) will illustrate the relative heating character istics. In Fig. 4 the.curve.Q3) 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 equipped with water pans for the purpose of adding moisture to the air in 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 adequffl,%to maintain a relative humidity above 25 percent on a zero day. 540 CHAPTER 22 1952 Guide REFFERENCES I I = B = R Installation Guide No. 5, Baseboard Heating Systems, Institute of Boiler and Radiator Manufacturers, New York. . a 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). 8 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. Transactions, Vol. 39, 1933, p. 237). (See also A.S.H.V.E. Trans actions, Vol. 41, 1935, p. 38, and Vol. 42, 1936, p. 29).. . I=B=R Testing and Rating Code for Baseboard Type of Radiation. (Institute of Boiler and Radiator Manufacturers, First Edition, July 1950). 4 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. Broderick (A.S.H.V.E. Transactions, Vol. 40, 1934, p. 443). . 1 Factors Influencing the Heat Output pf 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 (No. 29, April, 1942). 8 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. Severns (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). II 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). . 18 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). 15 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). . 16 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). i17 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, Vol. 22, No. 1, July, 1935, pp. 137-156). . 18 The Globe Thermometer in Studies of Heating and Ventilation; by T. Bedford and C. G. Warner (The Journal of Hygiene, Vol. 34, No. 4). 18 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). 80 Humidification for Residences, by A. P. Kratz (University of Illinois, Engineer ing Experiment Station Bulletin, No. 230, p. 20). CHAPTER 23 PANEL HEATING Definitions; Application Methods: Imbedded 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 ' *- 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 imbedded 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 are calculated in the conventional manner, the heat release from the heated surfaces is expressed in terms of heat output per square foot of surface per hour, and the room air temperatures, to be maintained are approximately the same as those maintained by heating systems employing cast-iron radiators, convectors, or warm air ducts. ' This chapter does not include a separate discussion of such topics as the influence of radiation on human comfort, the mechanisms by which human beings release heat, and other 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 this subject. 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 imbedded pip ing. More recently, the use of warm air ducts, and imbedded 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 tubing are used widely in ceiling, wall, or floor panel construction. . Tubing sizes used are f, ), f and J in. O.D., while piping is generally J, J or 1 in. I.P.S. Where coils are imbedded in concrete or plaster, no screw threads should be used for 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. : ; . For non-ferrous tubing, solder-sweated couplings are used. It is recom mended that a medium temperature solder of 95 percent tin--5 percent 541 542 CHAPTER 23 1952 Guide , antimony, or its equivalent, be used. All piping or tubing is, generally, subjected to a hydrostatic test of at least three times the working pres sure, but not less than 150 psig. . The more common forms of application of panel heating fall into the following general categories: (1) imbedded;, piping for ceilings; (2) im bedded piping for walls; (3) imbedded piping for floors; (4) air heated ceilings, walls or floors; (5) electrically heated ceilings, walls or floors. . Imbedded Piping for Ceilings When piping is imbedded-in ceilings, the construction used is generally one of the following: a. Pipe or tubing is imbedded in the lower portion of a concrete slab, generally very close to its lower surface. If plaster is to be applied to the concrete, the piping . (IRC TIC TO SUPPORTS SCRATCH COAT HEATING PIPING f CMBEDOlNG / . PIPES SUPPORTING MEMBERS ON 3 OR * FT CENTERS, use PIPE OR STEEL STRUCTURAL MEMBERS Fig' 1. Coils in Structural Concrete Slab . 'METAL LATH ^-FINISHED PLASTER CEILING Suspended Plaster Ceiling LATH APPLIED TUBING WIRE 5rT*LSli0,ST*.pipiii FINISH / BELOW LATH FINISHED PLASTER CCIUNG - Fig. 3. Coins in Plastkb Below Lath 3 COAT PtLAaSsTtEeRr/' 'METAL LATH * Vtmshed plaster ceiling 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, tnen the piping is installed about I in. above the undersurface of the slab. Fig. 1 shows 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 imbedded in a metal lath and plaster ceiling. If the lath is suspended to form a hung ceiling, the piping may be suspended as a prefabricated pipe coil so that the lath may be held by wire to the underside of the pipe coil. Pisster is then applied io the metal lath, care being taken to imbed the coil, as shown m 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 imbed the tubing, as shown in Fig. 3. - . . -. . d. Other forms of ceiling construction utilize prefabricated panels of metal, composition board, wood paneling, etc., having water warm piping, tubing or. chan nels 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 rous piping or tubing, with coil pipes spaced from 4^ to 9 in. on centers, de pending on the required output, pipe or tubing size, and other factors. Panel Heating 543 Fio. 4. Coils in Floor Slab on Grade Where plastering is applied to pipe coils, a standard three-coat gypsum ^plastering specification1 iafollowed, with a minimum of in. of cover below . 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. Insula tion 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. ' Imbedded Piping for Walls Although not so universally used as ceiling panels, wall panels may be constructed by any of the methods outlined for ceilings. 1 Imbedded Piping for Floors '. The construction for piping imbedded in floors will depend upon whether (a) the floor is laid on grade, or (b) the floor is above grade. . . . a. Both ferrous and non-ferrous pipe and tubing are used in floor slabs which rest on grade. The coils are constructed as either sinuous-continuous pipe coils, or arranged as header coils with the pipes spaced from 6 to 18 in. on centers. The coils are generally installed with 11 to 4 in.-of cover above the coils.. It is recommended that insulation be used to reduce the perimeter and reverse losses. Fig. 4 Bhows the . application of pipe coils in slabs resting on grade. Generally, a waterproofing, layer is desirable to protect insulation and piping. . b. Where the coils are imbedded in structural load supporting slabs above grade, construction codes may affect their position. Otherwise, the coil piping is installed in the same manner as described for slabs resting on grade. 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 Fig. 5. Warm Air Plaster Ceiling Construction . ; 544 CHAPTER 23 AtRKAcT IMPREGNATED 1952 Guide .... , . Fig. 6. Warm Aib Floob Panel Construction 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 19). .. 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 imbedded in a manner similar to hot water piping in concrete or plaster; (2) prefabricated electric heating panels to be attached, to room surfaces; and (3) electrically heated fabrics or other materials for applica tion to, or incorporation into, finished room surfaces. Again, the problem of compliance with applicable codes must be- considered. Figs. 7 and 8 indicate two methods that have been used. OUTPUT FROM PANEL SURFACES The heat transfer from a panel is accomplished by two basic heat trans fer processes: radiation and convection, which are considered in following paragraphs. Radiation Transfer The radiation transfer can be evaluated by means of the relationship set up by Stefan and Botzmann: . "'PM}] (i) STUO SPACE OrCi y*wMTiw ~-Al6tp LATH ! VT* FINISHED PIASTER Fig. 7. Electric Heating Cables in Plasteb ISOLATION INSULATION--* SEE DETAIL A1 IN PANEL HEATING PANEL ATTACHED TO JOISTS PREFABRICATED PANEL ATTACHED TO JOISTS DETAIL ELECTRIC RESISTANCE ELCMENT IN PANEL A Fig. 8. Prefabricated Electric Panel Panel Heating 545 where . q, = heat transfer by radiation, Btu per (square foot) (hour). ' T, = absolute temperature of panel heated surface, Fahrenheit.- ; Tw = absolute mean radiant temperature of all unheated surfaces, Fahrenheit. = the configuration factor (dimensionless). . --` F. = the emissivity factor (dimensionless). For large parallel planes or large enclosed surfaces as ordinarily: en countered in panel heating practice: .'. ci e. (2) tu = panel surface temperature Fig. 9. Heat Output by Radiation where .. ei and e, = emissivities of the respective surfaces. In heating practice ei and e% are usually equal to 0.9 and F, to 0.82. Also, the configuration factor F. 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: Irregularities in room surfaces and materials may introduce some error, m 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 values are shown in Fig. 9 for various surface temperatures. These values are applicable for either floor or ceiling panel radiation outputs. 546 CHAPTER 23 1952 Guide 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 *6 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. . b. The position of the surface. The basic general equation for natural convection from a flat surface is of the following form: 5. , . . (4) where q,, = 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. ' = 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 Pfeterson 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 fc 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 q< = 0.81 (i. - J.)1U (5) for heat flow upward from horizontal surfaces and small temperature differences, give results that check within reasonable precision the. con- Panel Heating 547 . vection 'output from floor panels, with temperature differences as recom mended. Curve A in Pig. 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 ceiling 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 obtained from Curve B in Fig. 10, based on the Nusselt and Henky equa tion "'- ' 9,, = 0.22 (U - <0,Jt . (6) / A / / 3L vAf/ A / 3r f /A ir y I- 1 -J 1 1 1 1 I t I 1 O 5 IO 15 20 29 39 35 40 49 50 55 00. Ai,0-tD PAHR OEG. . U = panel surface temperature U -- inside air temperature Fig. 10. Heat Output bt Convection from Floor and Ceiling Panels should 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 transfer 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 floor 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) 21.4 Convection (Fig. 10, Curve A for a temperature difference of 15 deg F) 16.9 Total useful heat transfer 38.3 548 CHAPTER 23 1952 Guide Example 2: Find the combined total useful heat transfer from a square foot of ceiling panel having a surface temperature of 100 F, when the average room air tem perature is 70 F and the mean radiant temperature UMRT of the unheated room sur faces is 60 F. Radiation . (Fig. 9 for UMRT of 60 F and t. of 100 F) Convection -- (Fig. 10, Curve B for a Ai of 30 F) Btu/(hr)(sq ft) - 35.3 15.5 Total useful heat transfer ' 50.8 Since the greater number of panel installations are designed for an average room air temperature of 70 F, it is possible to present in chart form (see Fig. 11) the relationship between panel output (radiation plus con vection) and the unheated mean radiant temperature-for various surface temperatures and panel positions based on 70 F inside air temperature. Panel Heating 549 Fig. 12 must be corrected by values obtained from Fig. 13. The follow ing example illustrated the use of Figs. 12 and .13. 1 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 U 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 Fig. 12. Inside air temperature = 70 F Relation of Overall Coefficient of Heat Transfer to Inside Subface Temperature 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 a. 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. No basement. Insulation will be used between slab and fill. d. Heating medium, hot water. e. Floor surface temperature, 85 F (Maximum). 550 C. / H'APTER 23 1952 Guide Fio. 13. Inside Wall Subfacb Tempebatube Cobkectton pob Inside . Aib Tempebatubb8 Otheb Than 70 F A* -- 70 > If Af is positive: tw' * Iwt correction . If AJ is negative: tw* TM iw -- correction - U inside &ir temperature , (* = {ihwHa wall surface temperature based on f* ** 70 F tw* actual ifwnHft 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 11. The calculations are shown in Table 1. The heat loss through the surface areas containing the heating medium is not included in the calculation. The calculated rate of heat loss will determine the amount of heat which must be supplied by the heating panels to the room. WEST Fio. 14. Room Plan fob Illustration of Method of Designing a Panel Heating System Data: Values of overall heat transfer coefficients as calculated: .1. Outside walls U =* 0J0 3 Ceiling U = 0.08 .3. Floor ` 4 Windows V = 0.30 V - 0.55 Panel Heating 551 Table 1. Calculated Heat Loss of Room (Fig. 14) . Surfaces Area Sq Ft o Calcuiation Ceiling...................... - 272 80 352 480 480 0.10 0.55 0.08 _ 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 ' Total heat loss................................................................................................... Heat Loss Btu/br 2,176 3,520 0 3,072 0 8,295 17,063 3. Determination of UMRT The calculations for determining UMRT are shown in Table 2. The inside sur face temperatures shown in the fourth column were determined from Fig. 12. Table 2. Calculation of UMRT Surface Area Sq Ft Inside Surface* Temperature F* Product (Area x Temperature) 0.10 0.08 0.55 272 352 480 80 1,184 65 70 66 43 17,680 24,640 31,680 3,440 77,440 Total of products _ 77,440 UMRT Total area 1,184 65.4 F 8 Values of inviH. wall surface temperature for various U values and outside design temperatures found in Fig. 12. - ' 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. 11. 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, t.e., 10 or more percent less, than the calculated heat 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 panel for various cover depths, tube or pipe sizes and spacings, and rate of heat 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. As sume that the panel haa J in. pipes, spaced on 12 in. centers, and that the depth of cover from top of panel surface to top of pipes is 2.5 ini The four sections of Fig. 552 CHAPTER 23 1952 Guide Fig. 15. Relation of Wateb Temperatures and Coil Outputs to Coil Spacing and Depth of Burt for Floor Coils in Slabs on Grade 15 are marked Part 1 to Part 4 and, as will be evident by following the dashed line on the chart, are used as follows: , Pari 1. Starting from the depth of cover (2.5 in.), proceed vertically to the line representing pipe spacing on centers (12 in.), and then horizontally to the firat ordi nate of Part 2. -- Part S. Move parallel to the nearest upward sloping line, indicating "2 in. & over" cover, to intersect the ordinate representing } in. pipe, and then proceed hori zontally to the first ordinate of Part 3. Pari S. Proceed parallel to and along 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 water temperature in the coil of 106 F. Part 4: From the water temperature 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 multiplier to be used. The reguired panel 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 imbedded in plaster on ceilings or walls, design pro cedure is simplified considerably by the physical limitations of the space available. For tubing fastened to the underside of lath, the largest practical size is f in. O.D., while for ferrous pipes above the lath, it is 1 in. I.P.S. Therefore, the actual tube or pipe size selected is usually determined by the length of coil circuit and its flow resistance in consideration of the available circulating head. In order to obtain a reasonably even heat distribution over the finished Panel Heating 553 plaster heating surface, pipes-, or tubes should be spaced on about 6 in. centers,, and not over 9 in. centers. Within these limitations it is found . in practice" that heat output rates do not vary too seriously with variations in pipe and tube size and tube spacing. '? ,: In generalr-for plaster ceiling panels with tubes or. pipes spaced on to 9 in. centers, the temperature of the circulating water is about 10 to 25 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 h When water is used as the heating medium, the piping layout-and ar rangement should- be based on the design principles outlined in-Chapter 21 for Two-Pipe Forced Circulation Systems. The pressure drops through the coils should be cairefully 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. - - " ' ' - 1" -;:k - - ' - " .. 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 21, Hot Water Systems, also apply to piping systems for panel heating. Control problems of panel heating systems are discussed"in Chapter S'g'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 structurarconditions, 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: . ... ''' " . '' REFERENCES 1 Standard Specifications for Gypsum Plastering, including Requirements for lathing and Plastering (American Standards Association, A42.I, 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 Associlion). 1 Various investigations of W. Nusselt (1915-1928) as discussed in Chap. 23 and Chap. 25, and tabulated in Author Index of Heal Transfer, by Max Jakob, Vol. I, 1949 (John Wiley and Sons, New York). * The Transmission of Heat by Radiation and Convection, by Ezer Griffiths & A. H. Davis (Special Report No. 9, 1922, Department of Scientific & Industrial Research, His Majesty's Stationery Office, London, England). 1 Radiation and Convection from Surfaces in Various Positions, by G. B. Wilkes and C. M. F. Peterson (ASHVE Transactions, Vol. 44,1938, page 513). 554 CHAPTER 23 1952 Guide BIBLIOGRAPHY Trend Curves for Estimating Performance of Panel Hating Systems, by B. F. Raber and F. W. Hutchin son (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 Itaber and F. W. Hutchinson (A.S.H.V.E. Transactions, Vol. 48, 1942,p.'35). ' -* A.8.H.VJ3L Research Report No. 1193--Radiation as a Factor.in the Feeling of Warmth in Convection Radiator and Panel Heated Rooms, by F. C. Houghten, Carl Gutberlet and E. C. (A.S.H.VJ3. Trans actions, Vol. 48, 1942, p. 85). Panel Heating and Cooling Analysis, by B. F. Raber and F. W. Hutchinson (AJ3.H.V.E. Transactions Vol. 47, 1941, p. 285). * Operating Results of a Residence Radiant Wall Heating System, by EL J. Rodee (AJ3.H.V.E. Transac tions, 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 (Beating and Ventilating, March, 1941, p. 35). Radiant Heating and Cooling, by F. El Gieseckis (Heating, Piping and Air Conditioning, June, July, Au gust, 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. Vanderweil (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.8.H.V.E. Journal Section, Heating, Piping and Air Conditioning, Oct. 1947; p. 113). -' Graphical Solution of Radiant Panel Areas, by W. P. Chapman and R. E. Fischer (Heating and Ventilat ing, Jan. 1948, p. 88).. . ., ._ - Elmbedding Coils in Radiant Heating Panels, by D. L. Mills and L. J. LaTart (Heating and Ventilating, Dec. 1947, p. 75). .s Radiant Heat with Copper Tubing, by D. L. Mills and L. J. LaTart (Heating and Ventilating, Nov. 1947 p. 95). s . Panel Heat with Copper Tubing--Experiment in Practice, by D. L. Mill* and L. 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.VJ3. 'Journal Section, Heating, Piping and Air Conditioning, Aug; 1947, p. 111). - ' Panel Heating--A Basic Discussion, by S. Eonso (American Ariiean, Oct. 1946, p. 68). Solar House Heated by a Warm Air Floor Panel, by John E. Peterson (American Artiean, Dec. 1946, p. 83). . Design Data for a Warm Air Floor Panel, by Axel B: Algren (American Artisan, Jan. 1947, p. 141). The Mechanism of Heat Transfer, Panel Cooling, Heat Storage; by Charles S. Leopold (Refrigerating En gineering, July 1947, p. 33). .. - Radiant Heating--Simplified Design and Installation (Copper and Brass Research Association, 1949). Laboratory Studies on Heai Flow Within a Concrete 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. Journal Section, Heating, Pip* ing and-Air Conditioning, April 1950, p. 109). Heat Flow Analysts in Panel Heating or Cooling Sections, by L. E. Hulbert, H. B. Nottage and C. V. Franks (A.S.H.VJS. Journal Section, Heating, Piping and Air Conditioning, April 1950, p. 117). Electric Analogger Studies on Panels with Imbedded Tubes, by Carl P.'Kayan (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, May 1950, p. 123). -` Books . ' Hot Water Heating, Radiant Heating and Radiant Cooling, by F. E. Giesecke, 1947 (Technical Book Co., P. O. Box 62, Austin, Tex.). ' ' Panel Heating and Cooling Analysis, by B. F.- Raber and F. W. Hutchinson,-1945 (John Wiley and Sons, New York). . . * - .. Radiant Heating, by T. Napier Adlam, 1947 (Industrial Press, 148 Lafayette St., New York). Radiant Heating, by R. W. Schoemaker, 1948 (McGraw-Hill Book Co., New York). Chapter V (pages 103-115) of Healing 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 Fundamentals, by W. H. Severn* and J. R. Fellows (John Wiley and Sons, New York, Second Edition, 1949). CHAPTER 24 UNIT HEATERS AND UNIT VENTILATORS Definitions; Unit Heaters: Classification, Application, Ratings, Location, Space Temperatures, Control, Piping, Boiler Capacity; Unit Ventilators: Ratings, Capacity Requirements, Application, Selection, Control, Location, Exhaust Flues; Window Ventilators 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 25. . . 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. The term unit ventilator denotes an assembly, the principal function of which is to ventilate.: Tt'may serve to circulate air within the space, or to introduce air from without the space, or may accomplish both purposes. The essential elements of a unit ventilator are a fan and motor, a heating element, a set of dampers, a housing, and outlet vanes or diffusers.. UNIT HEATERS Classification The various types of unit heaters which are at present available can usu ally be classified according to one of the three following methods: . 1. By type of heater.. Under this classification there are three types of heating elements-to be considered: (o) the steam or hot water type, (6) the ' electric type, and. (c) the direct fired type which may be gas, oil, or coal fired. 2. By type of fan. Under this classification there are two types of fans to be considered: (o) the propeller type1 and (b) the centrifugal type. Either type may be arranged for horizontal or vertical delivery of air. 3. By arrangement of dements. 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 (5) the blow-through type, in which the fan blows air through the heater. Unit heaters are available in any combination of the three preceding gen eral classifications. For example, the steam or hot water type may be 555 556 CHAPTER 24 / '> 1952 Guide Unit Heaters and Unit Ventilators 557 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. . Fig. 4. Propeller Fan Type Unit Heater--Vertical Blow Application of Unit Heaters '................. Steam or hot water unit heaters axe 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. 9.) There are a variety of applications which are favorable to the use of electric unit heaters. For supplemental heat in residence bathrooms, for the heating of ticket booths, Watchmen's offices, factory offices, locker rooms and other isolated rooms scattered over large areas, their use is peculiarly adaptable.. They are particularly useful in isolated and untended pump ing stations or pits where they may be thermostatically controlled to pre vent 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 used. The installation cost of gas-fired units is usually less than that of a type requiring thata 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 healers are of finned, welded steel, or, cast-iron construction, and equipped with centrifugal blowers. They are usually stoker-fired to insure proper firing of fuel. They are used principally in large industrial plants such as fpundries or assembly plants, and provide a convenient source of heat, are readily installed arid economical in Operation, since all heat given off by the surface of the heater remains in the heated space. There are three major factors.to consider in the application of unit heat ers, namely: (1) location of-unit, (2) air distribution, and (3) heating me dium. . Outlet Velocities .. . : Outlet velocities of unit heaters vary from about 400 to 2500 fpm, depend ing upon the type of unit arid-.the distance to which the air- is to be pro jected. Noise and drafts must be considered in the choice of air velocities, 558 CHAPTER 24 1952 Guide /^ , -since both increase with increase of air velocity. Velocities and blow dis tances for the various types of unit heaters illustrated in Figs. 1, 2, 3 and 4 are given in Table 1. ' .. . In the selection of unit heaters it is important to ascertain that the blow is sufficient. The blow-is dependent to a marked degree on the temper ature of air leaving the heater, as well as upon its velocity. (See discussion under heading of Inlet, Outlet, and Space Temperatures with Unit Heaters.) Air Outlets In order to direct the air to points desired and to diffuse the air to avoid drafts, unit heaters are commonly equipped with directional outlets, ad justable 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 horn- above an entering air temperature of 60 F. This applies to all types of unit heatera, 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- Table 1. Outlet. Velocities and Distance of Blow foe Vabious Ttfes of Unit Heaters . : Ttpb or Unit Hbateb ' . Outlet ' Velocities FPM Distances or Blow--Ft* 1500-2500 400-1000 1200-2200 20-200 30-100 70 * Refer to manufacturers* tables-for limits of blow. 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 2 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 code' 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 Unit Heaters and Unit Ventilators 559 Table 2.- Constants fob.Determining'the Capacity of Unit. Heaters fob; . Various Steam Pressures and Temperatures of Entering Air " (Based on. Steam Pressure of % psig and Entering Air Temperature of 60 F) ' ' Steam- ' ' '' Temperature or Entering Aib . Pbes- 8T7BB PSIO -10* 0 10" . . 20 30" 40* 50* .60* 70* 80* 90* 100* w ' cu >* B' O. O* 04 B H Se s . ' . .0 2 5 10 15 20 30 -40 50 - 60 . 70 . 75 80 00 100 1.54 1.50 1.64 1.73 1.60 1.45 1.50 1.55 1.64 1.71 1.86 1.07 2.06 2.13 2.20 ' 1 -77 1.87 1.06 2.04 2.00 2.26 2.28 2.31 2.36 2.41 2.16 2.18 2.21 2.26 2.31 1.37 1.41 1.46 1.55 1.61 1.68 1.78 1.86 1.94 2.00 2.06 2.09 2.11 2.16 2.20 1.27 1.32 1.37 1.46 1.53 1.19 1.24 1.29 1.38 1.44 1.11 1.16 1.21 1.29 1.34- 1.03 1.08 1:13 1.21 1.28 1.58: 1.68 1.77' 1.85 1.90 1.50 1.60 1.68 1.76 1.81 1.42 1.51 1.60 1.67 1.73 1.33 1.43 1.51 1.58 1.64 1.96 1.09 2.02 2<06 2.11 1.87 1.90 1.93 1.97 2.02 1.78 .1.81 1.84 1.88 1.93 1.70 1.72 1.75 1.79 1.84 0.96 1.00 1.05 1.13 1.19 0.88 0.93 0.97 1.06 1.12 0.81 0.85 0.90 0.98 1.04 0.74 0.78 0.831 0.91 0.97 0.67, 0.71 0.70 0.84 0.90 1.25 1.35 1.43 1.50 1.56 i.17 1.27 1.85 1.42 1.47 1.10 1.19 1.27 1.34 1.39 1.02 1.12 1.19 1.26 1.31 0.95 1.04 1.12 1.19 1.24 1.61 1.64 1.66 i:711.75 1.53 -1.4ft-- 1.37 1.55 1.47: 1.40 1.58. 1.50. 1.42 1.62 1.54 1.46 1.66 1.58 i:50 1.29 1.32 1.34 1.38 1.42 w .^ B O o 04 B H 0 1.48 1.41 1.33 1.25 1.18 1.11 1.03 0.96 0.89 0.82,, 0.75 0.69 2 1.52 1.44 1.36 1.29 1.22 1.14 1.07 1.00 0.93 0.86 0.79 0.73 5 1.57 1.49 1.41 1.33 1.26 1.19 1.11 1.05 0.98 0.91 0.84 0.77 - 10 1.64 1.56 1.48 1.40 .1.33 1.25 1.18 1.11 1.04 0.97. 0.90 0.84 . 15 1.60 1.61 1.53 1.46 1.38 1.31 1.24 1.17 1.10 1.03 0.96 0.90 20 1.73 1.65 1.57 1.50 1.42 1.35 1.28 1.21 1.14 1.07 1:00 0.94 30 1.80 1.73 1.65 1.57 1.50 1.42 1.35. 1.28 1.21 1.15 1.08 1.01 40 1.86 1.70 1.71 1.64 1.56 1.40 1.42 1.35 1.28 1.22 1.15 1.08 50 1.03 1.85 1.77 1.70 1.63 1.55 1.48 1.42 1.35' 1.28 1.21 1.15 60 1.07 1.00 1.82 1.75 1.67 1.60 1.53 1.46 1.40 1.33 1.26 1.19 t 70 2.02 1.94 1.87 1.80 1.72 1.65 1.58 1.51 1.44 1.38 1.31 1.2A O . 75 2.04 1.97 1.90 1.82 1.75 1.68 .1.61 1.54 1.47 1.40 1.33 1.27 80 2.06 1.99 1.01 1.84 1:77 1.70 1.63 1.56 1.49 1.42 1135 1.29 00 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 1.00 1.92 1.85 1.77 1.70 1.63 1.66 1.49 1.43 1.36 Note: To determine capacity at any steam pressure and entering temperature, multiply constant from table by rated capacity at GO F entering air and 2 peig. -. 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 is satis factory. . '. ' are made in the built-in-wall model, suspension model, arid free-standing or portable model. ' _ Electric unit heaters are rated on the energy input to the heater, expressed in terms of kilowatts, Btu or EDR. Quite often all three ratings are given in parallel columns in the catalogs. ~'r . Gas-Fired. Gas-fired unit heaters are built in both suspended and floor models, with either propeller or centrifugal type fans. They are available in a wide range of sizes from about 24,000 to over 4,000,000 Btu per hr ca pacity, and are usually rated in terms of both, input and output according to the approval requirements of the American Standards Association. Any gas-fired unit which is thermostatically controlled and has a pilot must 560 CHAPTER 24 1952 Guide have an element'in the pilot flame which Will automatically close the gas valve on pilot failure. . '. : .' Oil-Fired. The oil-fired unit heater is usually equipped with a centrifugal fan, and can be. obtained, in sizes ranging from 125,000 to 1,650,000 Btu per hr output capacity in standard units. It is furnished in either the floor-mounted or in smaller sizes in the suspended type. 'Stoker-Fired. The stoker-fired type of unit heater can be obtained in ranges of from 300,000 to 6,000,000 (or more) Btu per hr output capacity. Ratings are based upon delivered output at heater outlet.; 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 discharge side are used with the unit, areduction in air and heating capacity will result because of this added resistance. The percentage of this reduction in capacity will depend upon the characteristics of the heater, and on the type, design and speed of the fans, so. that no specific percentage reduction can he assigned for all heaters at a given added resistance. In general, however, propeller fan type units will experience' a larger reduction in capacity than housed centrifugal fan units for a given added resistance, and a given heater will have a larger re duction in capacity as the fan speed is lowered. The heat output to be expected under other than, free delivery conditions should be secured from the manufacturer. : .......... . .... Determining Unit Heater Requirements The formulas given in the section on Unit Ventilators may be used to determine unit-heater capacity requirements. ; ' . Location of Unit Heaters ; ' ; .. Care should be taken in the location of unit heaters to insure free air circulation to the intake. The best arrangement is to locate units so that they discharge air nearly parallel to.exterior walls; and in a direction which will produce a rotational circulation around the room. This is preferable to" directing the discharge against the outside walls; ' ' Various types and makes of unit heaters are illustrated in the Catalog Data Section of this edition! As hot blasts of air. in working zones are .usu ally objectionable, heaters mounted on the. floor should have their discharge outlets above the head line, and suspended, heaters should be placed in such manner and turned in such direction that the heated air stream will not be objectionable in the working zone. In the interest of economy, however, the elevation of the heater outlet and the direction of discharge should be so arranged that the heated air is brought as close above the head line as possible, yet not into the working zone. ,. 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 leaving the heater in order that the heated air may be forced into the occupied zone. ' . .. . .. - Inlet, Outlet and Space Temperatures with Unit Heaters ' i 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 iii the working zone of the space. In Unit Heaters and Unit Ventilators ... \ ,v1 561 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;. :Correspondihgly, units with lower dis charge air temperature will maintain: lower temperature differences than -units with higher, discharge temperatures.. DireetiOnal'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-ceiling temperature difference. -:' '- Sincethe outlet temperature of..air from a unit heater increases with'the temperature of the heating, medium-, such as high pressure steam,' heaters Fig. 5. Unit Heateb Connection to One-Pipe Gravity Steam System 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 forin 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 bp the same as that to be maintained in the room itself. ' -1 - 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. .' If the fain is controlled,: it is advisable to 562 CHAPTER 24 1952 Guide --.provide a temperature-operated switch to prevent the fan from starting until the heating element is heated throughout. Unit heaters may be used in summer as a means of circulating air to give some measure of com fort due to air motion. In such cases the heating-element should be shut off'from the source of heat. The thermostat which prevents the fan from starting until the heating element is heated, should be provided with a by pass switch, which, upon being closed, will permit the fan to be operated independently of the heating element. 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 / Unit Heaters and Unit Ventilators 563 common return to a boiler, with vent trap or condensate pump.and receiver, is shown in Fig. 6. The traps must pass air and condensate rapidly to.keep the return piping partially full of water. . Since unit heaters are often constructed with sufficient strength, the use -of high pressure steam in them is a common practice. As shown in'Fig. 7, the condensate and air reach the overhead return through traps, and check valves are located in the return, piping. It is, however, preferable to locate the high pressure return below the heater. . For two-pipe closed gravity return systems, the return from each unit should be fitted with a heavy-duty or blast trap, and an automatic air valve should be connected into the return header of each unit heater. Pro vision must be made to compensate for the pressure drop, by elevating the unit heater above the water line of the boiler or of.the receiver. Fiq. 6. Unit Heateb Connection fob Vacuum ob Vapob Ststem Discharging .. Condensation into Dbt Retubn . themselves to function as intended. The basic piping principles for steam systems are discussed in Chapter 20. 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 ample pipe capac ity is particularly,important. A method of connecting a unit heater to a one-pipe gravity system is illustrated in Fig. 5. When the return main is located above the boiler water line, an artificial water line must be created by providing an equaliz ing loop to prevent steam passing into the return, and thus into, other units. A piping arrangement where both the air and condensate pass through a Fiq. 7. Method of Connecting Unit Heateb to High Pressure Ststem _ In pump and receiver systems, the air may be eliminated by individual air valves on the heaters, or it may be carried into the returns as in vacuum systems, and the entire return system be free-vented to the atmosphere, provided all units, drip points, and radiation are properly trapped to pre vent steam entering the returns. ' . On vacuum or open vent systems, the return from each unit should be fitted with a large capacity trap to discharge the water of condensation, and with a thermostatic air valve for eliminating the.air, or with a heavy-duty trap for handling both the condensation and the air, provided the air finally can be elininated at some other point in the return system. For high pressure systems the same kind of traps may be used as with vacuum systems, except that they must be constructed for the pressure used. If the air is to be eliminated at the return header of tile unit, a high pressure air valve can be used; otherwise the air may be passed with.the condensate through the high-pressure return trap, and then eliminated at some other point in the system. . : Fig. 8 represents the connections to a hot water heating system. The air 564 CHAPTER 24 ^ 1952 Guide vefit is-not required if the main is-above the heater in. which case.air can be eliminated through the piping system. ; . ' . . ; ... . 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 wifi occur, plus an allowance .for pipe line' losses. It is unwise to iristall a single unit heater as the sole load on any boiler, particularly if the unit heater motorris started and stopped by thermostatic Control. The wide and sudden fluctuations of load that occur under such cpnditions 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 Unit Heaters and Unit Ventilators 565 hot water may-be employed, as the heating medium. ; Unit ventilators are intended primarily for use.in schools,, meeting rooms, offices, or other ap^ plications where the density of occupancy indicates the need for ventilation. In normal operation, the discharge air temperature from a unit ventilator is varied in accordance' with the room demaridk 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 mUt;be below, that.of the. rOoms. It is customary to equip unit ventilators with, control devices that prevent the delivery, of air at a temperature, that will cause cold drafts. Unit ventilators may be of the heating element or damper controlled type, con structed on the blow-through (Fig.-9)-'or .draw-through prmciple as [illus trated in Fig. 10. . ,.......... - . ... .. ... ; WINDOW Fig. 8. Method op Connecting Unit Heateb to Hot Wateb System rapid fluctuation. In most cases, and particularly where the boiler is coal- firedi .it. is advisable to use: two. or more smaller units instead, of one large unit heater. . : ... ' ... , . ;' Steam pressures tbelow 5 lb Can beused 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 con-e- sponding differential in pressure between the Supply and return piping should be maintained, by means of a vacuum. ` ... . . UNIT VENTILATORS '. A unit ventilator is essentially a. modified' unit heater. In addition to heating, it hais the, additional function of introducing outdoor air for ven tilation and cooling, 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 eooling effect to be varied while the fanfare operating continuously. Eitheristeamor forced Fig. 9. Typical Blow-Through Type Unit'Ventilatob Showing One op Many Arrangements of Dampers and Heating Elements .. Ratings of Unit Ventilators ; ; ... ' , : v 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 and 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-. -The1 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 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. 566 CHAPTER 24 1952 Guide Standard Code for Testing and Rating Steam Unit Ventilators.6 This code requires that the following rating information be supplied: ' . Rating Factors to be Specified. The rating of the unit ventilator shall specify: . a. Final temperature at different entering air temperatures. ., ft. 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. Fio. 10. Typical Draw-Through Type Unit Ventilator Showing One op Many Arrangements op Dampers and Heating Elements 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: o. 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 dr 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 3 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 Unit Heaters and Unit Ventilators 567 quired by the unit may be similarly divided as (1) heat required for ventila tion (Hr) and (2) surplus heat (Ht). 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 Hr and H, is the total heat (Ht) to be supplied by the unit ventilator. These quantities of heat are related by the following equations: H, = 0.24 IF (f -- Q Ht = 0.24 W (h -- to) H. = Ht - Hr = 0.24 IF (i, - 0 IF = d 60 Q . Ht = H. + 0.24 d 60 Q {t - to). (1) (2) (3) (4) (5) where . . d = density of air, pounds per cubic foot (0.075 lb per cu ft for Standard Air by definition). H, = surplus heat, Btu per hour. Hr = heat required to warm air for ventilation, Btu per hour. . Ht -- total heat requirements for both heating and ventilation, Btu per hour. Table 3. Typical Capacities of Unit Ventilators for an Entering Air . Temperature of Zero . .:: Cubic Feet or Aib peb Minute Anemometer Rating Standard Air Rating Total Capacity in Square Feet, Equivalent Di rect Radiation Capacity Available fob Heating the Room, Squabs Feet Equivalent Direct Radiation Final Aib . Temperature F Deg 750 500 1000 750 1260 1000 1560 1250 214 320 . 427 534 56 84 112 141 95 95 95 95 . Q = volume of air handled by the ventilating equipment, cubic feet per minute. t = temperature to be maintained in the room, Fahrenheit degrees. , to = outside temperature, Fahrenheit degrees. - ft = temperature of the air leaving the unit, Fahrenheit degrees. . IF = weight of air circulated, pounds per hour. .' 0.24 = specific heat of air at constant pressure (approximate value). Example1: The heat loss of a certain room is 24,000 Btu per hour, 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 Solution: Since the surplus heat is available to replace the heat loss of the. room, H, = 24,000 Btu per hour. Substituting in Equation 5: Ht = 24,000 + 0.24 X 0.075 X 60 X 1000 (70 - 0) = 99,600 Btu per hour t, = 24,000 + 70 = 92.2 F 0.24 X 0.075 X 60 X 1000 If in Example1 a 1000 cfm (Standard Air) unit were required, but only 568 CHAPTER 24 1952 Guide 25 percent of the air introduced were outdoor air, the solution would be as follows:- ' '1 - - ' ; : , . Ht = 24,000 + 0.24' X0.075 X 60 X 0.25 X 1000 (70 - 0) = 42,000 .. ' - 24,000 ' ' 0.24 X 0.075 X 60 X 1000 ' '' ................. 1 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'ufiit ventilator heating capacity may be made. The combined system employs a unit ventilator with sufficient heating 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 so that a fixed minimum of outdoor ah is introduced at all times. The amount of outdoor airmay be governed by state or local codes; or may be calculated by -the engineer to meet the need of the application.. In some cases, a variable aihouht of outdoor air is introduced depending on outside temperatures. This is done in order to conserve fuel, .with some sacrifice of ventilation. : . 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.' If the ventilation require ments are less than this value, some; air. may be recirculated from the room. With this quantity of air handled, it is possible to obtain satisfactory cooling in mild weather,: Since coohng is an important function, the unit ventila tor- 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 ffoiA 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: Cyde 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 Unit 'Heaters and Unit Ventilators 569 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 preven+ioverheating, 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-rrA 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 of 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 Fig. 11. Typical Window Ventilator of the room.. It is difficult to obtain proper air distribution if` the unit is installed either on an inside wall or in a corner 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 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 570 CHAPTER 24 1952 Guide vent opening will produce an objectionable draft. In such a case the velocT ity in the vent opening should not exceed 400 to 450j 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. 11 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. .' REFERENCES 1 See National Association of Fan Manufacturers standard definitions in Chapter 32. 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 1930. Code revised 1950. * Standard Code for Testing Hot Water Unit Heaters prepared by Engineering Committee of Industrial Unit Heater Association. Adopted by Industrial Unit Heater Association August 1942 and published September 1942. 1 A.S.H.V.E. Research Report No. 958--Temperature Gradient Observations in a Large Heated Space, by G. L. Larson, I). W. Nelson and O. C. Cromer (A.S.H:VJE. Transactions, Vol. 39, 1933, p. 243). A.S.H.V.E. Research Report No. 1011-- Tests 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). * 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). * 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 25 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 committee11 * * 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 classified1 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 outsidej 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.1 . 7. A Forced-Circulation Air Cooler is a factory encased assembly of elements by which heat is transferred from air to refrigerants.1 CLASSIFICATION OF UNIT TYPE EQUIPMENT . Field assembled apparatus as described in Chapter 29 can be designed in shape, size, and capacity for any application, with the refrigeration and 571 572 CHAPTER 25 1952 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. ; iurrfi If the"condensing unit and cooling and heating poil 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. ~r- ' -' .. : 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; 7J, 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 com dition of feeling cool, self-contained units, called room coolers, find exten sive arid economical application. These units are usually, restricted to summer and intermediate season operation, arid range from J to lj tons of refrigeration capacity. ... . . A special application of remote units is found iri the unit air cooler yrhiph is used extensively- iri 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 teriaperature 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, but since it contains no element of heat transfer, .it is treated in Chapter 32, 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.. (Jnit .Air Conditioners and Unit Air Coolers 573 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 Mcess 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' cqils 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 pf the casing. They are also available with flanges and flanged access ..doors topeririit 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 lj 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 wifl'usually last as long as the uriit '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. Iri 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 corrosiori resistant paint to prevent excessive oxidation and corrosion of the blowers. Some of the smaller1 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 full capacity of the coil. The cooling coils also perform the function of dehumidification. To prevent carryover of condensate, eliminator plates 574 CHAPTER 25 I' Fig. 5. Remote Floor Type Room Unit Aib Conditioneb 1952 Guide & Unit Air Conditioners and Unit Air Coolers 575 should be used if face velocities exceed 500 to 530 fpm, unless adequate means of catching the droplets are provided. f.'JWhen 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 over come 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. Filters. It is almost axiomatic that all units should have filters. Some small suspended units of 1 ton capacity or less, with low coil face velocities and propeller fans, are equipped 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 insure adequate filter surface, since the cross-sectional area of the Unit is seldom adequate for filter area. V-shaped or staggered filter arrange ments 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 or other sound deadeners. (For design of suitable sound deadeners see section Controlling Vibration from Machine Mountings in Chapter 40). 576 CHAPTER 25 1952 Guide / /- . MODIFICATIONS OF REMOTE UNITS Features of various modifications of remote air conditioners are given in'the 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 tpat 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 sueh as lithium chloride are used to remove .moisture , from the air. . fAs explained in; Chapter .37, 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 pnits are also available.for use with solid adsorbents such as silica gel. Remote Room Units ^; ; For individual rooms, with coolingdoad requirements of to 1$ 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,rs usually installed in place of an existing; radiator, is , shown in- Fig..f5. Furnished jvith chilled .water from a icentral plant,, these units; onerf;a satisfactory method1 of conditioning- existing, offices, potel, and apartment rooms. These units may be obtained withiffit^g;pnd outside; air;.con nections, bui'for: most'satisfactory apptjcfttfcn are ugedas suppiements to central systems that supply propeHy, conditioned andf.filtered, air to the .areas.served.. ' - - -- -. ...i',-;- f,- ; ; .-. Induction type units, using primary conditioned air under pressure to induce local circulation, are described in Chapter 29. ;. ni ... , . ' Self-Contained Units f .-.; -. ; 't A-typical.large selfrcontained Phil is'shown-in Elg, 6;'-;;It is essentially -a remote-vertical type conditioner mounted on tbp pf 'a sound -insulated enclosure containing the cbhdensing:iihit.?'Air'distfibdiibn dg-ohtaihed by means of grilles mounted' in the discharge plehum- when'the unit is located in the conditioned area. `'Duct 'distribution- of cohditioned air can be obtained. by1 removing.tlie plenum, 'connecting directly; to. the blower dis charge, and safing the top of the umt.a v ; : ' The heat generated 'by-the compression fbf refrigerant g^'es 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 7i, 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 577 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 duet connection; between? the unit and an .outside window, or ventilated air .Shaft is required to permit Fig. 6.'Self-Contained , Wateb-Cooled Aib , .Conditioner . ! , ..." -. i , . ... : .. . Fig. 7. Self-Contained Aib-Cooled. Unit . . . , Air, Conditioner .. i... .' , . 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 taining to the installation, of small motors. The exterior finish of the unit in 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 Fig. 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 intoThe conditioned area. A feature of the design shown in Fig: 7 is that the 578 CHAPTER 25 1952 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 38. . ; 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 self- contained type and (2) Standard Method of Rating and Testing Self- Contained Air Conditioning Units for Comfort Cooling2 covering the self- contained, 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* dehuinidifying 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: (1) 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 579 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*. Standard Rating Basis fob Self-Contained Air " Conditioning Units Functions All Types op Units Item Rating Condition Description .. Value All a Barometric Pressure ' . .. , : 29;92. in. Hg. Cooling 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 Water-Cooled d Water Temperature Entering Condensers Unit . e Water Temperature Leaving Unit ' Air - Cooled f ' and Evapor- Cooled Con-' densers Air Entering Outside Air Inlet (1) Dry-Bulb ' (2) Wet-Bulb 80 F 67 F . See Note 75 F 95 F 95 F 75 F Heating Humidifying Air Circula tion . g Unit Ambient and Total Air Entering Unit , , vided ;with h Heating Medium, Pressure or Heating . Temperature Function (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 jVok*' Rating shall be based on both ventilation and recirculated room air entering at 80 F dry-bulb end 07 F wet-bulb temperature. (The Note as given in .the code has been condensed in order to remove material not pertinent to this chapter). . . '` adjustment of air volume. Any such field adjustment should be made when filters 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 of unconditioned 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 the need for careful installation of the various sections of sectionalized 580 CHAPTER 25 1952 Guide /' units,. usjng;a sealing compound if necessary to prevent air leakage into the fanfseetion of the unit. , "r . 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 seal 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 support'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 ran 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 instkliing small remote or self-contained units with outside air conhfections'in buildings more than 6 stories high, the effect of wintertime Unit Air Conditioners and Unit Air Coolers 581 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,finhed-.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 fruite: 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 beiow 32 F, fin spacing may vary from 2 to 6. fins per inch, while above 32 F it may vary from 5 to 8 fihs per inch. Both direct expansion refrigerants and brine 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 application of the unit. In the larger sizes particularly, speed adjustment of the fan is generally provided to permit variation of the air delivery, and thus obtain a closer control of the relative humidity. While unit coolers are usually installed in the storage space, remote installation combined with 582 CHAPTER 25 1952 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 cooleri 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, mid 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. Since 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 583 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 umt 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-surface 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 posses 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 umt cooler, the final selection being based on the economical balance be tween umt cooler, the compressor, and the condenser. Procedures for rating and testing room coolers are given in an ASRE Standard* 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-- no coU; or according to type of air delivery to room as (1) free delivery fan, or (2) pressure fan. Natural convection air coolers are classified according to type as (1) external baffle, (2) built-in baffle, and (3) without baffle. Arrangement and Operation The refrigerant is usually supplied to the evaporator through a thermo static expansion valve, thus obtaining dry expansion in the evaporator. 584 CHAPTER 25 1952 Guide i- Many prime surface coils utilizes 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. r 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 , df air many times in excess of the'dir 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 ip 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.'. ' . ' .jv. . . .. -' . .. ;. .. . Unit location is also, important from the standpoint of. occupant com fort, low velocity outlets being.preferred for floor type units. High velo cityoutlets are acceptable in fur storage vaults, ice cream hardening rooms .and. other spaces where air motion. is Aot an important factor. . . ' . : In general, unit' air copiers should not be suspended in front of door openings,-or close to them where moist watm-air.will be drawn directly into the unit, each time: the doords: 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 tq 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 of 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 Circidart No. 13-42 end No. 16 ,in ASRE Standard No. 1&-R, Methods of Rating end Testing Air Conditioners. *' CHAPTER 26 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 and irons, wrought-iron, copper, and brass, has increased considerably during the past few years. The recent development of copper, brass, and bronze fittings which can be assembled by soldering or sweating, per mits the use of thin-wall pipe and thereby has reduced the initial cost of such installations. The following brief discussion indicates the variety of pipe materials and the types of pipe available. . _ Wrought-Steel Pipe. Because of its low.price, the great bulk of wrought pipe used for heating and ventilating work at the present time is of wrought steel. The material used for steel pipe is a mild steel made by the acid- bessemer, the open-hearth, or the electric-furnace process. Ordinary wrought-steel pipe is made either by shaping sheets of-metal into 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, lap- weld 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: ' . Seamless steel pipe is frequently used for high pressure work or where pipe is desired for close coiling, cold bending, or other forming operations. Its advantages are its somewhat 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 wherf bent. ' Wrought-Iron Pipe. Wrought-iron pipe is claimed to be more corrosionresisting than ordinary steel pipe, and therefore its somewhat higher first cost is.said to be justified on the basisof longer life expectancy. Wroughtiron 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 examination of polished and etched speci mens will readily disclose the difference. Cast-Ferrous Pipe. There are now available several types of cast-ferrous 585 586 CHAPTER 26 1952 Guide 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 1J in. to 6 in., and in standard lengths of 5 or 6 ft, with external and internal diameters closely approximating those of extra strongswrought 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. Steel pipe bearing a small alloy of copper or other alloying element, and iron pipe bearing a small amount of copper and molyb- Table 1. Dimensions of Schedules 30 and 40 and Standard Weight Pipe* External ; Internal Surface Diameter In. Weight pee Ft, Lb ClBCUtfPBBENCR, In. Sm d. j i & =3 S I 4 .W - iK 11 f! 1 d E ! s. Transverse Area, So In. r <3 aa S .a 3 s Length op Pipe, Ft per Sq Ft 1 00 Length op Pipe, Ft Con taining ICoFt Weight op Water, la per Ft -3 5 u 0.405 0.269 0.068 0X44 0X45 27 Ye 0.540 0X64 0.088 0.424 . 0.425 18 yk. 0.675 0.840 0.493 0.091 0.622 0.109 0X67 0X50 0X6S 18 0X52 14 1.272 1.696 2.121 2.639 0X45 1.144 1X49 1.954 0.129 0.229 0X58 0X54 0.057 0.072 0.104 0.125 0.191 0.167 0X04 . 0X50 9.431 14.199 2533.775 7.073 10.493 1383.789 5.653 7.748 754XG0 4X47 6:141 '473.906 0X25 0.045 0X83 0.132 vs 1 11HM 1.050 1X15 1.660 1.900 0.824 0.113 1.130 1.134 14 1.049 0.133 1.678 1.684 IW UH1X80 0.140 2.272 2.281 im 1.610 0.145 2.717 > 2.731 3X99 4.131 5X15 5.969 2X89 3.296 4.335 5.058 0.866 1X5S 2.164 2X35 0X33 0X64 1.495 2.036 0X33 0.494 0.669 0.799 3.637 2X04 2X01 2X10 4.635 3.641 2.768 2X72 270.034 166.618 96X75 70.733 0X31 0X75 0.65 0X8 12 2.375 -2H , 2.875 za3 3.500 4X00 2.067 0.154 2.469 0.203 3.068 0.216 3X48 0.228 3.652 5.793 7X75 9.109 3.678 11H 7.461 6.494 4.430 5X19 8 9.032 7.757 , 6.492 7.616 8 10.996 9.638 9.621 9X02 8 12X66 11.146 12X66 3X55 : 1.075 4.788 1.704 7X93 2.228 9X86 2.680 1.608 1X28 1.091 0.954 1X47 42.913 1X47 30X77 1X45 19479 1.076 . 14X65 1.45 2.07 3.20 4X9 -4 ` 4X00 4.026 0.237 i0.790 10X89 8 14.137 12.648 15.904 12.730 3.174 0.848 0.948 ' 11X12 5.50 5 5X63 5.047 0.258 14.617 14X10 8 17.477 15.856 24.306 20.006 4X00 0.686 0.756 7.198 8.67 6 6.625 6.065 0.280 18.974 19.185 8 20X13 19.054 34.472 28.891 5X81 0X76 0.629 4.984 12X1 8C 8.625 8.071 0277 24.696 25:000 8 27 096 25X56 58.426 51.161 7X65 0.443 0.473 2 815 22.18 8 8.625 7.081 0X22 28X54 28.809 8 27.096 25.073 58.426 50X27 8X99 0.443 0.478 - . 2X78 21.70 10C 10.750 10.136 0X07 34.240 35.000 8 33.772 31X43 90.763 80.691 10.072 0.355 0X76 10. 1G.750 10X20 0X85 40.483 41.132 8 33.772 31.479 90.763 78X55 11.908 0X55 0X81 1.785 34.95 1X26 34X0 12c 12.750 12X90 0X30 43.773 45.000 8 40.055 37.982 127.676 114.800 12 876 0X99 0X15 1X54 49.70 12 12.750 12.000 0X75 49X62 50.706 8 40X55 37.699 127.676 113.097 14X79 0X99 0X18 . 1X73 49.00 * Standard-weight wrought-iron pipe has approximately the same wall thicknesses and weights as con tained herein for steel pipe.. For exact dimensions, see American Standard for Wrought-iron and Wroughl- Steel Pipe, ASA B36.10. ' . ' t> Thicknesses shown in bold face type are identical with thicknesses for Schedule 40 pipe of ASA B36.10. - Same as Schedule 30, ASA B36.10.' ' ' . '. denum, have been claimed to possess more resistance to corrosion than plain steel pipe and they are advertised and sold under various trade names. , Copper Pipe and. Fittings. Owing to inherent resistance to corrosion, copper and brass pipe have always been' used in heating, ventilating, and water supply, installations, but the cost with standard dimensions for threaded connections has been high. The recent introduction of fittings which permit erection by soldering or sweating, allows the use of pipe with thinner walls than would be possible with threaded connections, thereby reducing the cost of installations. The initial cost of brass and copper pipe installations generally runs higher than the corresponding job with steel pipe and screwed connections in spite of the use of thin wall pipe, but the corrosive nature of the fluid Pipe, Fittings, Welding 587 conveyed or the inaccessibility of some of the piping may. warrant, use of a more expensive material than plain steel. The advantages of corrosion* resisting pipe and fittings should, be weighed against the correspondingly higher initial cost. - COMMERCIAL PIPE DIMENSIONS The two weights of steel and wrought-iron pipe commonly used are known as standard weight and extra strong, which correspond to Schedules 40 and 80, respectively, of the American Standard for Wrought-iron and WroughtSteel Pipe, dSA B36.10. The same external diameter is used for both Table 2. Standard Weights and Dimensions of Welded and Seamless Steel Pipe* Standard-Weight Pipe Extra-Strong Pipe . DoUBUb Extrao Pipxb Octside No. op Duke* Threads ten. In. per In. Schedule 30. Wall Thick ness, In. Weight per Ft, Lb TAC Schedule 40 . Wall Thick ness, In. Wright per Ft, Lb TAC Schedule 60 Wafl Thick ness, Id. Wright per Ft, Lb Plain Ends Schedule 80 Wall Thick ness, In. Weight per Ft, Lb Plain Ends WaO Thiekness In. Weight perFt, Lb Plain Frwfs vs vXs M H 1 I Ye W 2 JH 3 3M 4 5 .' 6 8 10 12d 0.405 0X40 0.675 0X40 1.050 1X15 1.660 1.900 2X75 2X75 3X00 4.000 4X00 .5X63 6.625 8.625 10.750 12.750 27 18 18 . 14 14 UK UH tm 8 8 8 8 8 8 8 8 8 -- ____ ; -- 0.277 0X07 0X30 , -- 0.068 0.088 0.091 0.109 ____ ____ __ * - -------- 0.113 0.133 0.140 0.145 0.154 0X03 0.216 0X26 0X37 25X0 35.00 45.00 0X58 OXSO 0X22 0X65 0X75 0X6 0.43 0X7 0X5 1.13 1.68 2X8 2.73 3.68 5X2 7.62 9X0 10X9 14X1 19.19 28X1 41.13 50.71 ------____ -- -- . -------- - 0X00 54.74 oxood 65.41 0X95 0.119 0.126 0.147 0X1 0X4 0.74 1.09 0.154 1.47 0.179 2.17 0.191 : 3X0 0.200 3.63 0X18 5.02 0X78 7.66 0X00 10X5 0X18 12X1 0X37 . 14.98 0X75 0.432 oxoo - 20.78 28X7 43X9 -- -- 0X94 0X08 0X58 0.382 0.400 0.436 .0X52 0.600 0.636 0.674 0.750 0X64 0X75 .( 1.71 2.44 3.66 5.21 6.41 9.03 13.70 18X8 22X5 27X4 38X5 53.16 72.42 -- From Standard Specifications for Welded and Seamless Steel Pipe of the American Society for Teeting MateriaU, A.S.TJd. Designation A120. * Sizes larger than these shown in the table are measured by their outside diameter, such as 14 in. outside diameter, etc. ' These larger sizes will be furnished with plain ends, unless otherwise specified. The weights will correspond to the manufacture!,* published standards although it is possible to calculate the theoretical weights for any given size and wall thickness on the basis of 1 cu in. of steel weighing 0.2833 lb. b The American Standard for Wrought-iron and Wrought-Steel Pipe ASA B36.10-1930 has assigned no schedule number to Double Extra-Strong pipe. .. c A 10 in. Standard Weight pipe is also available with 0.279 in. wall thickness, but this wall is not covered by a Schedule Number. `` .. . ^ Owing to a departure from the Standard-Weight and Extra-Strong wall thicknesses for the 12 in. womtnwl size, Schedules 40 and 60, Table 2 of the ASA B36.10-1939, Standard for Wrought-iron and Wrought-Steel Pipe, the regular Standard and Extra-Strong wall thicknesses (0.375 in. and 0.500 in.) have been substituted. weights of each nominal size for manufacturing reasons, as well as to afford interchangeability in threading and other elements associated with fabri cation and erection. Hence, the difference in wall thickness is accom panied by a corresponding change in inside diameter. In sizes up to 14 in., pipe is designated by its nominal size which corresponds roughly to the inside diameter of Schedule 40 pipe. In sizes 14 in. and upward, pipe is designated by its outside diameter (O.D.), and the wall thickness is speci fied. . . While the demands for pipe for the heating and ventilating industry are reasonably well served by Schedule 40 (standard weight) pipe, the erection 588 CHAPTER 26 I' 1952 Guide '` of pipe by welding sometimes warrants using' lighter wall thicknesses. The considerations governing pipe wall thickness and its relation to joint design are covered in the American Standard Code for Pressure Piping, ASA B31.1-1942, see Section 122. Standard schedules of pipe thick nesses are contained in the American Standard for Wrought-Iron and Wrought-Steel Pipe, ASA B36.10, which includes standard-weight and ' . , ' Table 3. Standard Dimensions and Weights, and Tolerances in Diameter and Wall Thickness for Copper Water Tubes* . (AU tolerance* in line table are flue and minve except ae otherwise indicated) Average Out side Diameter - Wall Thickness In. Theoretical Weioht, Lb per Ft Standard Actual Water Outside Size, In. In. Tolerance. In. TtpeK Ttpe L Ttpe M Drawn Temper j N o m in a l N o m in a l Tolerance Type L Type M 8 g - a < M 0.250 0.002 0.001. 0.032 u 0.375 0.002 0.001 0.032 12 0.500 0-0025 0.001 0.049 H 0.625 043025 0X01 0.049 H ,K : la 0.750 0.875 1.125 <1.375 0-0025 0.003 0.0035 0.004 m 1.625 : 0X015 2 ;: 2.125 0.005 2H 2.625 .0.005 3 3.125 0.005 0X01 0.001 0.0015 0.0015 0.049 0.065 0.065 0.065 0.002 0.002 0.002 0.002 0X72 0X83 0.095 0.109 3M 4 5. 6 3.625 4425 5.125 6.125 0X05 0X05 0.005 0X05 0.002 0.002 0.002 0.002 0.120 0.134 0.160 0.192 8 . 10 12 8.125 . 10.125 . . 12.125 0X06 0XQ80.008 +0.002 -0.004 +0.002 -0X06 +0.002 -0X06 0.271 0X38 0.405 Sa s 0X03 0X04 0X04 0.004 0.004 0X045 0X045 0.0045 0.005 0.007 0.007 0X07 0X08 0.010 0.010 0.012 0X25 0X30 0X35 0.040 0X42 0.045 0.050 0X55 0.060 0.070 0.080 0X90 0.100 0.110 0.125 0.140 0X16 0X18 0.020 0.200 0X50 0X80 aI ao S5 "o & 0.0025 0.0035 0.0035 0.0035 0.025 0.025 0.025 0X28 0.0025 0.0025 0.0025 0.0025 0.085 0.134 0X69 0X44 0.068 0.126 0.19S 0X85 0.06S 0.107 0.145 0X04 0.0035 0.004 0X04 0X045 0X30 0.032 0.035 0X42 0.0025 0X03 0.0035 0.0035 0.418 0.641 0X39 1.04 0X62 0.455 0.655 0X84 0X63 0X28 0.465 0.682 0.0045 0.006 0.006 0.007 0.049 0X58 0.065 0X72 0X04 0.006 0.006. 0.006 1X6 2X6 2.93 4.00 1.14 1.75 2.48 3X3 0.940 1.46 2.03 2.6S 0.007 0.009 0X10 0.010 0.083 0.095 0.109 0.122 0X07 0.009 0X09 0X10 5.12 6X1 9.67 13.9 4X9 5X8 7.61 10.2 3X8 4.66 6.66 8.92 0X14 0X16 0X18 0.170 0X12 0X54 0X14 25X 0X15 40X 0X16 57X 19X 30.1 40.4 16X' 25.6 36J * From Standard Specifications for Copper Water Tube of the American Society for Testing Materials AJS. T.M. Designation B8S-41. ' Note 1:--For copper gas and oil burner tubes, the tolerances shown above for various wall thiftlrnpan^ (type K) apply irrespective of diameter. Note 2:--For tubes other than round no standard tolerances are established. These tolerances do not apply to condenser and heat exchanger tubes. extra-strong thicknesses in Schedules 40 and 80, respectively, and eight other schedules of varying wall thickness to provide, for different service conditions. Dimensions and other useful data for Schedules 30 and 40 pipe are given in Table 1. Table 2 from AJS.T.M. Specifications A53 and A120 combines the schedule thicknesses of ASA B36.10 and the old series designations. 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 number of lengths ordered may be jointers which are two pieces coupled together. 3 * I i` . '% J * Pipe, Fittings, Welding 589 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. 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 U. S. Government and the American Society for Testing Materials. There are Table 4. Thermal Expansion of Pipe in Inches per 100 ft* {For superheated steam and other fluids refer to temperature column) Saturated Steam Elongation in Inches per 100 rr prom -- 20 F up * ' Saturated ' Steam ' Elongation in Inches per 100 pt raoM --20 F up Tem Vacuum Inches ofHg. Pressure Psig perature Fahren heit CastIron Pipe Degrees Steel Pipe Tem <SsrWrougbtIron Pipe Pressure Prig perature Fahren heit CastIron Pipe Degrees Steel Pipe Wrought - Iron . Pipe ' Copper Pipe 29.39 28.89 27.99 26.48 24.04 20.27 14.63 6.45 ... __________ __ _ ........ ...... . ........ _ .. -- -20 0 20 40 60 80 100 120 140 160 180 200 0 0.127 0.255 0.390 0.518 0.649 0.787 0.926 1.051 1.200 1.345 1.495 0 0.145 0.293 0.430 0.593 0.725 0.898 1.055 1.209 1.368 1.528 1.691 0 0.152 0.306 0.465 0.620 0.780 0.939 1.110 1.265 1.427 1.597 1.778 0 0.204 0.442 0.655 0.888 1.100 1.338 1.570 1.794 2.008 2.255 2.500 2.5 10.3 20.7 34.5 52.3 74.9 103.3 138.3 180.9 232.4 293.7 366.1 220 240 260 280 300 320 340 360 380 400 420 440 1.634 1.780 1.931 2.085 2.233 2.395 2.543 2.700 2.859 3.008 3.182 3.345 1.852 2.020 2.183 2.350 2.519 2.690 2.862 3.029 3.211 3.375 3.566 3.740 1.936 2.720 2.110 2.960 2.279 3.189 2.465 .3.422 2.630 3.665 2.800 3.900 2.988 4.145 3.175 4.380 3.350 4.628 3.521 4.870 3.720 5.118 3.900 5.358 a From Piping Handbook. by Walker and Crocker. This table gives the expansion from -20 F to the tem perature in question. To obtain the amount of expansion between any.two temperatures take the differ ence between the figures in the table for those temperatures. Fot example, if a steel pipe a installed at a tem perature of 60 F and is to operate at 300 F, the expansion would be 2.519 -- 0.593 = 1.926 in. three standard wall-thickness schedules of copper water tubing classified in accordance with their principal uses' as follows: Type K--Designed tor underground services and general plumbing service. Type L--Designed for general plumbing purposes. Type M--Designed for use with soldered fittings only. . ' 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 is essential as in hidden replacement work, or where as few joints as possible are desired as in 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 classes are extensively used with soldered fittings. Standard dimensions, weights, and diameter and wall-thickness toler ances for these classes of copper tubing are given in Table 3. Copper pipe is also available with dimensions of steel pipe. Refrigeration lines used in connection with air conditioning equipment also employ copper tubing extensively. For refrigeration use where tubing absolutely free from scale and dirt is required, bright annealed copper 590 CHAPTER 26 1952 Guide 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 100 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 the line. ... . 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 hotwater 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 iri 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 is relatively complicated.1 The following approximate method, however, has been found to give reasonably good results and is deemed to be suf ficiently accurate for most heating installations. Fig. 1 shows several types of expansion bends commonly used for taking Pipe, Fittings, Welding 591 up thermal expansion. The amount of pipe, L, required in each'of these bends may be computed from Equation 1. ' . L = 6.16 VOA : (1) where ^ : ' - L = length of pipe, feet. D = outside diameter of the pipe'used, inches. A = the amount of expansion to be taken up, inches. . .. . This formula, based on the use of mild-steel pipe with wall thicknesses, 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 of the, bend should not exceed about twice the height, since for a given total length of pipe in the bend, the height 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 1J 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 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 to 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 work of the floor above. For long runs of vertical pipe subject to considerable thermal expansion, either the hangers should be designed to prevent ex 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 AmericanStandard taper pipe thread, ASA B2.1-1942 is used: This thread is cut 592 CHAPTER 26 1952 Guide with a taper of 1 in 16 measured on the diameter of the pipe so as to secure a tight joint. The number of threads per inch varies with the pipe size. Threads for fittings are the same, except that it is regular practice to furnish straight tapped couplings for Schedule 40 pipe 2 in. and smaller. For steam<pressures in excess of 25 psi, it is recommended that taper-tapped couplings be used to obtain a tight joint. These may be secured by ordering line pipe* which is used for oil piping, the couplings of which are provided with taper-tapped threads and may be used. with regular mill-threaded standard weight pipe. Thread lengths should be in accordance with ASA B2.1. Right-hand threads are used unless otherwise ordered. To facilitate drainage, some elbows have the thread tapped at an angle to provide a pitch of the connecting pipe of $ in. to the foot. These elbows are RBTDGERATOT TYFC rURED-TUBtKG FITTINGS ' . &A COMPRESSION TUQMG FilUNGS FLAftOHUSNG FITTINGS * Fia. 2. Copper ob Brass Tubing Fittings , 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. 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 3$ 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. Pipe, Fittings, Welding 593 5. 45Table American Standard Dimensions of Elbows, Tees, Crosses, and _ ~ A40.3-1C rH Car Brass** Nominal Size* Laying Length. TetTEll and Cross** Laying Length, EU With External Shoulder laying Length, 45Deg EU laying Length. 45 Deg EH Externa) Shoulder Inside Diameter of Fittings,* . Min. Metal Thicknes8^ Wrootbt Metal Metal Thickness* Min.* Bona or FnnKOS H 1 J Q 0 ' T R T and R E,Min. a .X 96 X 16 96 96 X 0.31 ' 0.08 0.048 0.030 0.378 96 0.43 0.08 0.048 0.035 0.503 x J6 96 96 96 0.54 0.09 0.054 0.040 0.628 X 96 '96 X X 0.78 0.10 0.060 0.045 0.878 i X Vs 96 96 1.02 0.11 0.066 0.050 1.1285 ix X 1 . 96 96 1.26 0.12 0.072 0.055 1.3785 IX l ix X. X 1.50 0.13 0.078 0.060 1.629 2 IX IX 96 X 1.98 0.15 0;090 0.070 2.129 ixIX m X X 2.46 0.17 0.102 0.080 2.629 3 IX X l . 2.94 0.19 0.114 0.090 3.129 ix3)4 4 2 2X IX 2X X IX `96 3.42 0.20 0.120 0.100 3.629 3.90 0.22 0.132 0.110 4.129 5 6 3X 3% .--- . 196 m -- 4.87 0.28 0.168 0.125 5.129 5.84 0.34 0.204 0.140 6.129 All dimensions given in inches. . a This size is-the nominal bore of the tube. . - k These dimensions may be used for wrought-metal fittings as well as for cast-brass fittings at wnufm*- turer'e option. "This dimension is the same as the inside diameter Class L tubing (American Standard fiiwrififtattonff for Copper Water Tube, ASA H23.1-1939 (A^S.TJkf. B88). ^ Pattons shall be designed to produce body thicknesses given in the table. Metal thielmwa< at no point shall be less than 90 percent of the thicknesses given in the table. e This dimension has the same thicknesses as Type L tubing. * These dimensions are minimum, but in every case the thickness of wrought fittings should be at-least as heavy as the tubing with which it is to be used. ' Note 1:--Wrought fittings, as well as cast fittings, must be provided with a should or stop at the bottom end of socket. . * Note 2:--Street fittings with male ends are for use in connection with other fittings illustrated. - As in the case of pipe, several weights of fittings are manufactured. Recognized American Standards for the various weights are as follows: Cast-iron pipe flanges and flanged fittings for 25 lb (sizes .4 in. and larger), 125 lb, and 250 lb maximum saturated steam pressure, ASA B16b2, B16a, and B16b, re spectively. Malleable iron screwed fittings for 150 lb maximum saturated steam pressure. ASA B16c.. Cast-iron screwed fittings for 125 and 250 lb maximum saturated steam pressure ASA B16d. Steel flanged fittings for 150 and 300 lb maximum steam service pressure, ASA B16e. . The allowable cold water working pressures for these standards vary from 43 lb for the 25 lb standard, to 500 lb for the 300 lb steel standard. . . War standard ratings in effect for the duration of the emergency per mitted higher ratings for certain sizes of the 125 lb cast-iron flanged ;594 CHAPTER 26 I^ 1952 Guide fitting standard, and for 300 lb steel flanges and flanged fittings, than those 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 ;-retum bends, which may be of either the close or open pattern, and may be cast with either a back or side outlet; tees'; Table 6. American Standard Dimensions of Elbows, 45-Deo Elbows, Tees and Crosses (Straight Sizes) for Class 125 Cast-Iron Screwed Fittings, ASA B16a-1939 Pipe, Fittings, Welding 595 Table 7.. American Standard Dimensions of Tees; . Crosses* (Straight Sizes), and Elbows for Class 125 Cast-Iron Flanged Fittings, ASA B16a-1939 Elbow Tee Cross 45 deg elbow `A c Nominal ' Pips . SlZB ' CSNTEB . to End, . ' Elbows. Tees and Cbossks CENTEE to End, 45. Dm Elbows BB V Length op Thread, Mm. Width ' op Band, Mm. ' Inside Diakethb op Fitting Min. Max. <7 B Mbtal Thickness, Min. Outbids Diameter op Band. Mir. ' H- K H 5* l i>* 1)4 2 2)4 3 3)4 4 5 6 8 10 12 0.81 0.95 1.12 1.31 1.50 1.75 1.94 2.25 2.70 3.08 3.42 3.79 4.50 5.13 6.56 8.08b 9.50b 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 4.28 5.16 5:97 0.32 . 0.36 0.43 0.50 0.58 0:67 0.70 6.75 0.92 0.98 1.03 1.08 1.18 1.28 1.47 1.68 1.88 0.38 0.44 0.50 0.56 0.62 0.69 6.75 6.84 6.94 1.08 1.06 1.12 1.18 1.28 1.47 1.68 1.88 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 8.625 10.750 12.750 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 8.725 10.850 12.850 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 0.550 0.690 0.800 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 10.63 13.12 ' 15.47 , All dimensions given in inches. ` Patterns shall be designed to produce castings of metal thickness given in the table. Metal thickness at no point shall be less than 90 percent of the thickness given in the table. '. 'b Applies to elbows* and tees only. 1 ` 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 lines or free escape of air in water lines. Fittings for copper tubing are available in the soldered, flared, or com pression types. Illustrations of each of these types are shown in Fig. 2. A AA Nominal Pipe Sresb-* . CbNTKUTO . Face Tees, CBOSSeSA*^ . and Elbows Face to Face Tbss AND Crosses*-* B Cram to Fact Lono Radius Elbow**** : ./c . ' ' 'Center to Fact 45 Deo 'Elbows Diameteb OP Flanas Thickness op Flange. Mm. MetalIi Thickness or Boot 1 m 2 2)4 3 3)4 4 5 6 8 10 12 14 O.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. 3)4 354 4 4% 5 5)4 6 0)4 7)4 8 9 11 12 14 , 15 16K 18 22 25 28 31 34 7 7)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 0)4 7 , 75* 3)4 9 105* 11)4 14 16)4 19 21K 24 26M 29 34 41M 49 56)4 64 m 2 2)4 2)4 3 3 3)4 .4 4)4 5 5)4 0)4 7)4 7)4 8 3)4 m u 15 18 21 24 4k . 4)4 5 6 7 7)4 3)4 9 10 11 13M 16 19 21 1 23)4 25 27)4 32 385* 46 53 59)4 % )4 . 9& K 5* % % UA :1 m m 1)4 IK m 1% m 2)4 2K 2K 25* 56 . 56 tz zl % K K : 56 : K. A *56 lK . H6 IK 1)4 His IK . 1% 2 All dimensions given in inches. . .* Crosses both straight and reducing sizes 18 in. and larger herent weakness in the citing design. . be reinforced to compensate for the in . k Size of all fittings listed indicates nominal inside of port. .. ' c Tees, side outlet tees, and crosses, 16 in. and smaller, reducing on the outlet, have the same center to face, and face to face as straight size fittings corresponding to the size of the larger opening. Sizes 18 in. and larger, reducing on the outlet, are made in two lengths, depending on the size of the outlet. - . ** Tees and crosses, reducing on run only, carry same dimensions center to face and face to face as a straight sue fitting of the larger opening. '- '' -. * Reducing elbows and side outlet elbows carry 'same dimensions center to face as straight size'elbowa corresponding to the size of the larger opening. .. . . * Special degree elbows, ranging from 1 to 45 deg, inclusive, shall have the same center to face *s 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 straight line flow and is the angle between the flange faces. ' " '' . .- * Side outlet elbowB shall have all openings on intersecting center lines. -- k Body thickness at no point shall be less than 87* peroent of the dimensions given in the table. ' 596 CHAPTER 26 1952 Guide Fittings for copper pipe of /PiS dimensions are available in screwed or soldered types of connection. Table 5. 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, while the flared and soldered types are used in both large and small sizes. An American Standard, A<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 Table 8. ` American Standard Dimensions fob Butt-Welding Elbows, Tees, , Caps, and Lapped-Joint Stub Ends, ASA B16.9-1940 Nominal Pot 8m [ Outbids ' Dumzteb ' 90-Deg i Elbows -A Cbntsb-to-End 45-Deg Elbows B ' Of Ron Tee ; C*. i \a tyt 2 2K 3 3K 4 5 6 8 10 12 ; i.3i5 1.660 < 1.900 2.375 ! 2.875 3.500 . 4.000 4.500 5.563 6.625 8625 10.750 12.750 ik m 2A 3 3% 4K 3% 6 7K 9 12 15 18 % i m m ;m 2 2A 2K 3K 3% 5 6 Vi7K m `VA 2A m 3 3A 3% m 5% 7 8A 10 ,CaP8 m m IK IK 2 2K 2K 3 3K 4 5 6: . LapfedJoint Stub Ends Length 4 .4 4 6 6 6 6 6 8 8 8 10 10 Radius of FriRllet Diam. of fcr K As A Mb , &% % 3ie Ke ; ; : Mi ; K= K 2 2K 2% 3`A 4K 5 SK 6As 7As 8K 10% 12A - 15 . All dimensions given in inches. - - * Thft'diTnt>TMnrm of welding tees cover those which have side outlets from one Bise less than half the size of the run-way opening of the tees to full size. * ' b Dimensions E and F are applicable only to these fittings in schedules up to and including Schedule 80, ASA Standard B36.10-1939. . The shape of these caps shall be ellipsoidal and shall conform to the requirements of the AJ3.MJ3. Boiler Construction Code. .. d This dimension is for standard machined facings in accordance with*American Standard for Steel Pipe Flanges Flanged FittingB (ASA B16e-1939). The back face of the lap shall be machined to conform to the 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. 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 the market for these fittings. For this reason formulation of an American Standard for these fittings was abandoned by the ASA in 1936. Pipe, Fittings, Welding .597 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 A-in. raised face. The standard facing for steel flanged fittings for 150 and 300 psi is a A-in. 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 with 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 6, whereas the dimensions for 125 lb cast-iron flanged fittings are given in Table 7. ' For low temperature service not to exceed about 220 F, a number of paper or vegetable fiber gasket materials will prove satisfactory; for plain raised face flanges, rubber or rubber inserted gaskets are commonly em ployed. 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.. WELDING Erection of piping in heating and ventilating installations by means of fusion welding has been commonly accepted in the past few years, as an alternate method to the screwed and flanged joint. Since the question of economy of welding as against the use of screwed and flanged fittings is dependent on the individual job, the use of welding is generally recom mended on the basis of 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. Fusion welding, commonly used in erection of piping, is defined as the process of joining metal parts in the molten, or molten and vapor states, without the application of mechanical pressure or blows. Fusion welding embraces gas welding and electric arc welding, both of which are commonly' used to produce acceptable welds. Welding processes and procedure are described in various publications. Welding application requires the same basic knowledge of design as do the other types of assembly, but, in addition, requires a generous know ledge of the sciences involved, particularly as to welding qualities of metal, their reaction to extremely high temperatures, and the ability- to determine and use only the best quality welding rods. This requirement applies equally to employer and employee, with the employer accepting all of the 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 groups.8-4-5 In general, the wall thickness and chemical analysis of the 598 CHAPTER 26 1952 Guide pipe are the governing, factors,'not the working pressure. There are a number of safety codes which govern the installation of welded piping in many cities and states. Some of the more prominent are listed at the end of this chapter.4-6'8 . . . A complete line of manufactured steel welding fittings is now available, Table 9. American Standard Dimensions, of Steel Welding Neck and Slip-on PSIWelding Flanges fob Steam Service Pressure Rating of 150 (Gage). . at a Temperature of 500 F, and 100 PSI (Gage) at 750 F,. - ASA B16e-1939 ... . Pipe, Fittings, Welding 599 are included in the American Standard. Larger sizes also are available in some types of fittings. The welding bevel which is a straight 37 -deg V for wall thickness | in. and below, and a U-bevel for thicknesses heavier than J in., conforms to the recommended practice of ASA Standard B16e-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 9 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 10. American Standard Dimensions of Socket-Welding Elbows, Tees, Cbosses, 45-Deg Elbows, and Couplings Nominal Pm i.Sm- .Dzawetkb or Flakgb. Thickness F'olgf.* - Mur. DuttSTsa OF Hub Hub Diam. BzounaNQ ChamOfFer^-* Lsnoth Thro Hub* iKSfOB Du1C of Pin Schedule 40e 0* Q X H r J H 3K K \K 3% K l . . ,'4K K IK m . K. m 5 7K 2 6K 2H 7 K 3 .m % 3K 8K 7K 49 5 - -. 10 6 11 7K >K 1: 8 13H IK 10 16 1% 12 19 IK 14 O.D; .21 .IK 16 O.D. 233^ IK 18 O.D. 25 1% 20 O.D. 27K 1% 24 O.D. 32 IK IK IK i*K 2K . 2K 3K 3% 4K: 4% 5K 6K 7% 9'K. 12 14K 15K 18 19K 22 26K 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 IK 0;62* 2K 0.82* 2K 1.05* 2K 1.38* 2K ; 1.61* 2K 2.07* 2K 2.47* 2K 3.07* 2'K 3 3.55* 4.03* 3K 5.05* 3K ; 6.07* 4 7.98* . 4 4K 10.02* .... : 5 To Be 5 Specified 5K by 5% Purchaser 6 Boas or &AP-ON Flanges Min. Duic OF *CBirocllte No. OF . Bolts fim OF Bolts W 0.88 2K 4 K 1.09 2K 4 K 1.38 3K 4 K 1.72 3K 4.. K 1.97 3K 4 K 2.44 4K 4 H 2.94 -5K 4 % 3.56 6 4K 4.06 7 8K 4.56 7K 8 K 5.66 8K 8 K 6.72 9K 8 K 8.72 11K 8 K 10.88 14K 12 K 12.88 17 12 14.19 18K 12 16.19 21K 16 lK l 18.19 22K 16 IK 20.19 25 20 IK 24.19 29K 20 IK All dimensions* given in inches. '. ' B A raised face of M fl in. is included in thickncts offlange minimum and in length through hub. . b The outside surface of the welding end of the hub shall be straight or tapered at not more than 0 deg. 0 Dimensions H and J correspond to the outside and inside diameters of pipe as given in ASA B36.101039, Schedule 40. . * These diameters are identical with the diameters of what was formerly designated as Standard Weight Pipe of the corresponding sizes. . and a dimensional standard7 has been prepared under the procedure of the American Standards Association to unify heretofore divergent dimensions for the same type welding fittings as produced by different manufacturers. Standard dimensions for steel butt-welding elbows, tees, caps, and lappedjoint stub ends are given in Table 8. - Dimensions for eccentric and con centric reducers, and 180-deg return bends are not shown in Table 8, but Centeb to Bottom op Socket Nom inal. Pxpb SlZB 90-Deg Mini mum Ella, Tees, Crosses Depth op Socket - e*S3 1 45-Deg Ells g rg-e s UJ . Coup lings Dis tance Be tween Bottom Socketb Boss DiaMETEB OP Socket, Mini mum Minimum Socket Wall Thickness 1 oo Jo3 Jo3 CO CO Bobe Diameter op Fittings Sched. 160 Sohed. 160 Sohed. 80 Sched. 40 Sched. 80 Sched. 160 A .A .E B C" D H Ms Ms H 0.420 0.125 0.125 0.269 0.215 H $4 Ms Ms H 0.555 0.125 0.149 0.302 H 96 Ms H 0.690 0.125 0.158 0.423 *4 H w Vi 0.855 0.136 0.184 0.234 0.622 0:546 0.466 Ha MHH 1.065 1.141 0.193 0.273 0.824 0.742 0.614 1 a H 1M Q 1.330 0.166 0.224 0.313 1.049 0.957 0.815 1H a 1M 1W `M `H. h 1.675 0.175 0.239 0.313 1.380 1.278 1.160 Ma 2H m 1M 1 m 1M 1 m H . 1.915 0.181 .0.250 0.351 1.610 1.600 1.338 M 2.406 0.193 0.273 0.429 2.067 1.939 -1.689 2H H 1H Mi 1H 1M M - 2.906 0.254 0.345 0.469 2.469 2.323 2.125 3 M 2M m 1V4 IH H 3.535 0.270 0.375 0.546 3.068 2.900 2.626> AH dimensions are given in inches. . ... * Dimension C is 1J times the MmWl pipe thickness, mmiTnvrm, but notthan ip, Reducing sizes have same 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 10.8 VALVES . Valves are made with both threaded and flanged ends for screwed and bolted connections just as.are pipe fittings. ,: 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 600 CHAPTER 26 1952 Guide 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 to 250 lb saturated steam working pressure, although most manufacturers also make valves for medium pressure up to 175 lb steam working pressure; 11.Table American Standard Contact Surface to Contact Surface Dimensions of Cast-iron and Steel Flanged Wedge Gate Valves, ASA B16.10-1939 . . e The connecting end flanges of 175 lb valves are the same as those on 250 lb valves* ,Notb 1Where dimensions are not given, the sizes either are not made or there is insufficient demand to warrant the expense of unification. .- Note 2:--Female and groove joint facings have bottom of groove in same planeas flange edge, and center to contact surface dimensions for these facingB are reduced by the amount orthe raised face. - 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 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 Pipe, Fittings, Welding 601 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 11. End-to-end dimensions for steel butt-welding valves in sizes up to 8 in., inclusive, are the same as those given in Table 1.1 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 ndividual taste. - Ordinary steam valves may be used for hot water service by drilling a rs-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. 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. Wert, S. Smith, E. T. Cope (The Detroit Edison Company). * See API Specification 5L for Line Pipe, American Petroleum Institute. Standard Manual on Pipe Welding (Heating, Piping and Air Conditioning Con tractors National Association, Second Edition, 1951). Welding Handbook (American Welding Society, 1942). 602 CHAPTER 26 1952 Guide . * ASME,Power-BoilerCode, American Society of Mechanical Engineers. ` American .Standard Code for Pressure Piping, ASA B-31.1--1942, American Standards Association. . . ., ' . o Marine Engineering Regulations of the Coast .Guard, American Bureau oJ 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^S. Navy, Bureau of Ships, April,.1940. ... American Standard, Steel Butt-Welding Fittings, ASA B16.9-1940, American Standards Association. . . American Standard, Steel Socket-Welding Fittings, ASA B16.11-1946, American Standards Association. .. .' CHAPTER 27 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 thus 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 i. 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 pier 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 F, 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). The total annual heat loss from the entire line = 1.624 X 169.4 X 165 (linear ft) X 4000 (hr) = 181,600 Mb. (Mb = 1000 Btu.) Example S: Coal costing $11.50 per ton and having a calorific value of 13,000 Btu per pound is being burned in the furnace supplying steam to the pipe line given in the previous example. If the system is operating at an overall efficiency of 55 percent, determine the monetary value of the annual heat loss from the line. Solution: The cost of heat per 1000 Mb supplied to the system = 1,000,000 X 11.5 (dollars) + [13,000 (Btu) X 2000 (lb) X 0.55 (efficiency)] = $0,804. The total cost of heat lost per year = 0.804 X 181:6 (thousand Mb) = $146.00. 603 604 CHAPTER 27 1952 Guide ~ . PIPE INSULATIONS 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 inBtu per (hour) (linear fool) (Fahrenheit degree difference between the pipe and surrounding still air at 7OF) Nominal Size (Inches) * X` iH ]U , . - 23 M 43X -5 6 8 10 12 120 F Hot Water 150 F 180 F 210 F 227.1 F (5 Lb) Steam 299.7 F (50 Lb) 337.9 F (100 Lb) 60 F 0.465 0.555 0.684 0.847 v 0.958 1.180 1.400 . 1.680 1.900 2.118 2.580 3.036 3.880 4.760 5.590 80 F . 0.495 0.605 0.743 0.919 1.041 1.281 1.532 1.825 2.064 2.302 2:804 3.294 4.215 5.180 6.070 Temperature Difference , 110 F - 140 F 0.546 0.666 0.819 1.014 1.148 1.412 1.683 2.010 2.221 2.534 3.084 3.626 .4.638 5.680 6.670 . 0.584 0.715 0.877 1.086 1.230 1.512 1.796 2.153 2.433 2.717 3.303 3.886 4.960 6.090 7.145 157.1 F 0.612 0.748 0.919 1.138 1.288 1.578 ' 1.883 ' 2.260 2.552 2.850 3.470 4.074 5.210 6.410 7.500 227.7 F* 0.706 0.866 1.065 1.324 1.492 1.840 2.190 2.630 2.974 3.320 4.050 4.765 . 6.100 7.490 8.800 267.9 F 0.760 0.933 l;147 1.425 1.633 1.987 *.363 2.840 3.215 3.590 4.385 5.160 6.610 8.115 9.530 Table 2.. Heat Loss fbom Horizontal Tarnished Copper Pipe Expressed in Btu per (hour) (linear foot) (Fahrenheit degree difference between the pipe and surrounding still air at 70 F) , Nominal Pipe ' Size . (Inches) . ' Hot Water (Type K Copper Tube) 120 F 150 F 180 F 210 F Steam (Standard Pipe Size Pipe) 227.1 F (5 Lb) 297.7 F (50 Lb) 337.9 F (100 Lb) Temperature Difference *X 1H IX 2IX* 2M 3 3H 4 ., 4H 5 ;6 8 50 F 0.250 0.340 0.440 0.500 0.580 0.730 0.880 1.040 1.180 1.460 1.600 1.840 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 0.657 1.143 1.343 1.535 1.715 . 2.071 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 terials are supplied in segments for assembly on large pipes. The sectional coverings are generally supplied with a pasted-on canvas jacket. Blanket insulations are sometimes used for wrapping large pipes, particularly where removal, for frequent servicing of-the pipe is necessary.. Fittings and bends are commonly covered with portions of standard; preformed Pipe Insulation 605 Table .3, External Surface per Linear Foot of Pipe Nominal Pipe Size (Inches) Surface Area (Sq Ft) x . 0.22 x 0.275 1 0.344 IX 0.435 0.498 Nominal Pipe Size (Inches) 2 2X 3 3X 4 Surface Area (Sq Ft) 0.622 0.753 0.917 1.047 1.178 Nominal Pipe Size (Inches) ` 5 6 8 10 12 Surface Area (Sq Ft) . 1.456 1.734 2.257 2.817 3.338 , : 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 canying 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 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. / 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. Individual manufacturer's materials will, of course, vary in conductivity to some extent from these values. The heat losses through 1, l j, 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. 1, 2, and 3. Table 4. External Surface per Linear Foot of Copper Tubing Outside diameter J in. greater than nominal size ' Tube Size . (INCHES) x X 1ix IX Surface Area (Sq Ft) 0.164 0.229 0.295 0.360 0.426 1 Tube Size (Inches) 2 2X 3 3X 4 Surface Area (Sq Ft) 0.556 0.687 0.818 0.949 1.080 Tube Size (Inches) 5 6 8 Surface Area (SqFt) 1.342 1.604 2.128 : -- 606 CHAPTER 27 1952 Guide Table 5. Abba of Flanged Fittings, Square Feet* Nominal Pipe Sub (Inches) 1 IH 2 2H .3 34H 4* 5 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 2141 3.43 4.41 0.438' 0.510 0.727 0.84S 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 I.874 2.16 2.76 3.74 4.28 4.99 5.46 6.02 7.76 II.09 15.60 18.76 _ Tee Standard Extra' Heavy 1.235 1.481 1.815 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 ' Including areas of accompanying flanges bolted to the fitting. Standard' thicknesses of 85 percent magnesia pipe covering are not exactly 1 in. However, the loss through any given thickness of insulation can be obtained by interpolation. Also, the losses through, any of the insulations given in Table 6 can be obtained by multiplying the losses obtained from Figs. 1, 2, or 3 by the factors given in Table 7. Pipes operating at high temperatures are frequently insulated to the Table 6. Thermal Conductivity (fc) of Various Type Pipe Insulations . . .for Medium and High Temperature Pipe* Expressed in Btu per {hour) {square foot) {Fahrenheit degree temperature difference ; .. .. . per inch) Types op Insulating Materials Density Lb/Cu Ft Temp. Rangb op Accepted . Use Mean Tkmpbratubb, F Dbg 100 '200 300 400 500 Corrugated Asbestos--Type - 4 Ply per 1 in...................................................... 6 Ply per 1 in.................................................. 8 Ply per 1 in........... .......................... . . -- Laminated Asbestos-1--Type - 11-14 11-13 15-17 18-20 30-35 10-15 25-30 13-15 TJp to 600 F Up to 300 F Up to 300 F Up to 300 F Ud to 700 F Ud to 800 F Ud to 1900 F Up to 1200 F 0.39 0.45 0.51 0.57 0.68 0.80 0.51 0.59 0.69 0.49 0.57 0.65 0.39 0.40 0.63 0.34 0.44 U.4& 0.66 0.39 0.49 0.50 0.44 0.54 0.55 0.49 ii `u 0.54 * Average values from laboratories for insulating materials of various manufacturers. Table 7. Pipe Covering Factors - Types op Insulating Materials Temperature Difference, Pipe to Am, F Dbg 100 200 300 400 500 Corrugated Asbestos--Type Mineral Wool--Type.............................................................. Diatomaceoua 8uica--Type...................................................... Brown Aabestoe Fiber--Type.............................. '................ 1.30 1.19 1.15 0.96 0.98 1.37 0.86 1.36 1.23 1.19 0.98 1.00 1.36 0.88 1.43 1.27 1.23 1.00 1.02 1.35 0.91 L02 1.05 1.35 0.93 L04 1.07 1.34 0.96 Pipelnsulation 607 best, advantage by combining a high temperature insulation near the-pipe with a moderate or low temperature insulation around it as an outerflayer: 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 Fig. -1. Heat Loss Through 1 In. Thick 85 percent Magnesia Type . .. Covering 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 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 608 CHAPTER 27 1952 Guide transferred per square foot of outer surface of the insulation is given by the equation: u lag. n Pipe Insulation 609 . After the true heat loss is obtained, the loss per square foot of pipe' sur face can be calculated from the relationship: , :' , . where 1 = ?o(r/r,) , ' ; qi = Btu per (hour) (square foot outer surface of pipe). .. Fig. 2. Heat Loss Through 1J In. Thick 85 percent Magnesia Type .. Covering - where q,, = Btu per (hour) (square foot of outer surface of insulation), ri = outer radius of pipe or inner radius of insulation, inches, n = outer radius of insulation, inches. : k = thermal conductivity of insulation, Btu per (hour) (square foot) (Fahrenheit degree per inch). (, = temperature of inner surface of insulation, Fahrenheit degrees, it = 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. Fig. 3. Heat Loss Through 2 In. Thick 85 percent Magnesia Type .' Covering :: The heat loss through two or more thicknesses of insulation applied to a pipe can be calculated by means of the equation: ii -- ti q. r. .log. nn + (2) where r< = outer radius of second layer of insulation, inches. r. = outer radius of last layer of insulation, inches. The method of solving Equation 2, which is the most difficult of the two, is given in Example 3. Example 8: 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. - '. 610 CHAPTER 27 . : 1952' Guide . i Solution: ln figuringthe heat loss from Equation 2, it is necessary to first make an assumption for the outer surface temperature it and the temperature between thei 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. Firstassume an outer surface temperature of 140 F and a temperature-of 570 F between the two-rna-; terials corresponding to a mean temperature of (1200 + 570) 2 or 885 F for the dia- tomaceous silica and (570 4- 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. ' 1200 - 140 ' 6.312 8.312 8.312 log. 3.312 8.312 log, 6.312 0.865 + 0.5 1060 = 98.3 Btu. 6.2 + 4.85 The temperature drop from the outer surface of the insulation to the surrounding' air for a heat loss of 98.3 Btu is found from Fig. 4 to be 57 F for a 16-in. O.D. cylin drical surface, or 57 + 80 F room temperature = 137 F surface temperature: Since a 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: go 1200 - 138 = 98.4 Btu. 6.2 + 4.58 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 Pipe Insulation 611 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 ito;the new assumptions are (1200 + 586) -5- 2 = 893 and (586 4- 138) -s- 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 F, 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 -i- 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, is avoided. ' Fig. 4. shows the loss of heat from canvas-covered, cylindrical surfaces of various outside diameters when the surface to air temperature difference is low. The data are from tests made at Mellon Institute. . . The frequent practice of omitting insulation on that portion of a pipe which passes through a masonry wall, or which may be in contact with other metals, should be avoided. Physical contact between the pipe sur face and other structural materials of high thermal conducitivity will re sult 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 Example 4: If the steam line given in Examples 1 and 2 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. Tne saving due to insulation is then 181,600 - 33,500 = 148,100 Mb per year. From the solution of Example 2, it was found that the heat supplied to the system 612 CHAPTER 27 1952 Guide 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. * Solve problems as indicated by dotted line, entering chart at lover left-hand scale Fio. 5. Thickness op Pipe Insulation to Prevent Condensation on Outer Surface* 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 Pipe Insulation 613 moisture to the cold surface. There are a number 'of methods of pro- during vapor seals; Some of which have been worked out by insulation manufacturers to suit their products, and others by applicators and users, v Unless .time-proven methods are known, specifications of insulation man ufacturers ghould be obtained and followed carefully. - .. , . 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 approximate required thickness of insulation to prevent condensa tion on pipes and flat metallic surfaces may be' obtained from Pig; 5 in Table 8. Heat Gains fob Insulated Cold Pipes Bates of heat transmission giveninBluper (hour) (Fahrenheit degree temperature difference between fluid in pipe and surrounding still air) Based on materials'having conductivity, k -- 030 - Nominal Pipe - Size (Inches) H 1 }X j2 d 3H 4 5 6 8 . 10 12 Ics Water Thickness Thickness of Insulation (Inches) Btu Per Linear Foot Btu Per Sq Ft Pipe Surface 1.5 0.110 0.502 1.6 0.119 0.431 1.6 0.139 0.403 1.6 0.155 0.357 1.5 0.174 0.351 1.5 0.200 0.322 1.5 0.228 0.303 1.5 0.269 0.293 1.5 0.295 0.282 1.7 0.294 0.248 1.7 0.349 0.239 1.7 0.404 0.233 1.9 0.455 0.201 1.9 0.559 0.198 1.9 0.648 0.194 Brine Thickness Thickness of Insulation (Inches) Btu Per Linear Foot Btu Per Sq Ft Sur/ace 2.0 0.098 0.446 2.0 0.111 0.405 2.0 0.124 0.352 2.4 0.131 0.300 2.5 0.134 0.270 2.5 0.151 0.244 2.6 0.170 0.226 2.7 0.186 0.202 2.9 0.191 0.183 2.9 0.209 0.176 3.0 0.241 0.165 3.0 0.259 0.150 3.0 0.318 0.140 3.0 0.383 0.135 3.0 0.438 0.131 . Heavy Brine Thickness Thickness of Insulation (Inches) Btu Per Linear Foot Btu Per Sq Ft Pipe Surface 2.8 0.087. 0.394 2.9 0.094 0.340 3.0 0.104 0.294 3.1 0.113 0.260 3.2 0.118 0.238 3.3 0.134 0.214 3.3 0.147 0.197 3.4 0.162 0.176 3.5 0.176 0.167 3.7 0.182 0.154 3.9 0.202 0.138 4.0 0.228 0.130 4.0 0.263 0.116 4.0 0.309 0.110 4.0 0.364 0.108 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 the next thinner,. commercial insulation in cases where an intermediate thickness is indicated. Heat gains for pipes insulated with a material having an installed conducitivity of 0.30 Btu per (sq ft) (hr) (F deg per in.) are given in Table 8. inis 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. 614 CHAPTER 27 .1952 Guide / - ' -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 insu lation necessary to take-care of still water in pipes at various water and surrounding;-air. temperature conditions. Because, of. the damage and 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 conductivity 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 Table 9. Data fob Estimating Requirements to Prevent Freezing of Water in Pipes with Surrounding Air at --18 F Nominal Pipe Sizb (Inches) Number op Hours to Cool 42 F Water to Freezing Point Water Flow Required at 42 F to Prevent Freezing. Pounds per Linear Foot or Pipe per Hour X 1 IX .2 -. 3 .4 5 0 S 10 12 . Thickness of Insulation in Inches (Conductivity, 0.30) 2 0.42 . 0.83 1.40 1.94 3.25 4.55 . 5.92 7.35 10.05 . 13.00 -15.80 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 i.i6 2.02 2.90 5.03 7.20 9.69 12.20 17.25 22.70 28.10 12 1 0.54 R 0.68 . R 0.84 0.95 1 1.24 8 1.47 I 1.73 . i 1.98 - 1 2.46 :B . 2.96 | 3.43 .3 * 0.45 0.55 0.68 0.75 0.94 1.11 1.29 1.46 1.78 2.12 : 2.45 4 0.40 0.48 0.58 0.64 0.79 0.93 1.06 1.19 1.43 1.70 1.93 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 visable to double the rate8 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 wafer 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 onefifth 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 . Pipe-Insulation 615 . 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: the outer surface of the 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 the1 Table 10. Thickness of Pipe Insulation Ordinarily Used Indoors* Thickness of Insulation ' . Steam Pressure . Steam Temperature ' . Psig Fahrenheit or Condition Degrees Pipes Larger Than 4 In. . Pipes 2 In. to 4 In. - Pipes X In. to IX In* 0 to 25 25 to 100 100 to 200 Low Superheat Medium Superheat ,, High Superheat 212 to 267 267 to 338 .338 to 388 388 to 500 500 to 600 600 to 700 1 in.1H in. 2 in. 2X in* 3 in. . 3X in. 1 in. 1 in. IX in. 2 in. . 3 in. 1 in* , 1 in. 1 in. 1M m. 2 in. 2 in. ` * AQ piping located outdoors or exposed to weather is ordinarily insulated to a thickness i in.' greater than; shown in this table, and covered with a waterproof jacket. . . 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. .. ECONOMICAL THICKNESS OF PIPE INSULATION . 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 typicalexample. In using the chart, start with the scale at the left bottom; margin representing 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-i 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 616 CHAPTER 27 1952 Guide Fig. 6. Chart fob Determining Economical Thickness of Pipe Insulation Pipe Insulation 617 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.* ' UNDERGROUND PIPE INSULATION Underground steam distribution lines are carried in protective struc tures of various types, sizes and shapes (see Chapter 28); ' Detailed data 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 Table 11. Thickness of Loose Insulation fob Use as Fill in Underground Conduit Systems Steam Pressure Pbio or Condition Steam Temperature Fahrenheit Degrees Minimum Thickness op Insulation in Inches 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 ik 2 2K IK m 25 to 125 267 to 352 2 2'A 3 IK IK Above 125, or superheat 352 to 500 2K 3 3K IK IK Minimum Distance Between Steam and - Return i 1K IK resistant wire, then sew on a wire-inserted asbestos fabric jacket with wire. 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 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 to 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 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- 618 CHAPTER 27 . 1952. Guide ^^ -' .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 tem perature difference for use with the chart when, applying it for underground pipe line estimates. __ .' , REFERENCES ..i Heat Loss from.Copper Piping, by R. H. Heilman (Heating, Piping and Air Con ditioning, September, 1933, p. 458). ' ' . . `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, Octoberl947, p.118). .' ' * Handbook of the National District Heating Association, Second Edition, 1932. ' 4 Theory of Heat Losses from Pipes Buried in the Ground,. by J. R. Allen A.S.H.V.E. Transactions, Vol. 28, 1920, p. 335). . CHAPTER 28 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. Some 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 36. . STEAM DISTRIBUTION PIPING . 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 matter, since the local conditions control the layout, little can be said re garding it. J 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, how ever, is a small part of the total at times of maximum load. Miscellaneous 619 620 CHAPTER 28 1952 Guide " steam requirements such as laundry, cooking, or process, should be indi vidually calculated. The steam requirements for water heating should 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 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 hot 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 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. . 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 75 psig is usually demanded, although 30 psi 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 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 26. 3. A proper hydrostatic test should be made on the assembled line before the insulation and the top of the conduit are applied. The hydrostatic test pressure 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. Since it is difficult to make a concrete or masonry conduit absolutely water-tight, provision should be made for some seepage. The pipe should be protected by a waterproof jacket over the insulation, and the seepage drained from the inside of the conduit. Underdrainage of the conduit is generally provided for by a tile drain laid in crushed stone or gravel under- District Heating 621 neath the conduit. The tile underdrain should be carried to the sewer or some other drainage point. Manholes are required at intervals for access 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. ^ "''ono Layer Offer Ptper ; Covered WWi Hot Thr And Pitch Standard ihhknest Pipe Covering wilh Wfeferproof Jacket Vd. Sewer Crock Bell & Spigot Joint Fiq. 1. Constbuction Details of 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 20. . CONDUITS FOR PIPING Conduits for steam pipes buried underground should be reasonably waterproof, able to withstand earth loads and to take care of the expansion and contraction of the piping without strain or stress on the couplings, or without affecting the insulation or conduit. Expansion of the piping must be carefully controlled by means of anchors and expansion joints or bends so that the pipes can never come in contact with the conduit. Anchors can be anchor fittings or U-shaped steel straps which partially encircle the pipes, and are firmly bolted to a short length of structural or cast steel set in concrete. In general, cast steel is preferable to structural steel. 622 Ci H-APTER 28 1952 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- Fig. 2. Connections pob Reducing Valve Without Bt-pass 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 partially or 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. Distri ct'jHeating 623 PIPE TUNNELS Where steam heating 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 work starts here Not*--All viIvm, fittings, and. traps up to and Including customer's control valve to bo at toast equal to AmorU lean Standard ISO lb. S. S. P Pipe to bo Sched ule 40. : Continuous-flow 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 permits1 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. Fig. 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-condensable gases, (See Chapter 42, Corrosion). Most district heating companies enforce certain regulations regarding the consumer's installation, partly to safeguard their own interests, but 1 Code for Pressure Piping, B31-I, 1942, American Standards A ociatton, Paragraph 408, p. 115. 624 CHAPTER 28 1952 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 tKe 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 625 Because of the lack of coincidence between the heating system load and the hot water demand, a greater amount of heat 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. 1 / S. Seat supply.should be graduated according to variations in the outside temperature. The maximum in economical operation and satisfactory heating can only be ob tained by the use of automatic temperature control (See Chapter 38). . METERING The perfection of fluid meters has contributed as much to the advance ment 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 orFig. 5. MEraon Installing a Water Heater and Economizer in a Gravity Heating System 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 practice to 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, as it permits the heat to be adjusted according to variations in sunshine and wind. S. Residual heat in the condensate should be salvaged. . This heat may be salvaged by means of a cooling coil, or as is more frequently done, by a water heating economizer (see Fig. 5) which preheats the hot water supply to the building. The condensate from the heating system, after leaving the trap, passes through the economizer. The supply to the hot water heater passes through the economizer, absorbing heat from the condensate. If the hot water system in the building is of the recirculating type, the recirculating connection should be tied in between the economizer and the water heater proper, not at the economizer inlet, because the recirculated hot water is itself at a high temperature. Fig. 6. Gravity Installation for Condensation Meter 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 flow traps are used, a vented receiver is not necessary, but is desirable. Fig. 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 section of stream, under constant head, is used as an indication of the rate of 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 626 CHAPTER 28 1952 Guide -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 offlow or'total flow. This mechanism , may be either mechanical or electrical. The electric flow meter has the advantage of being able to locate the instru ments 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.:..(l) . Fio. 7. Orifice 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. 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 fines. Larger size mains are metered by installing a 2 in. meter in a by-pass with a restricting orifice in the main fine. .: . District Heating 627 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: (1) 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: (o) purchase price, (6) 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. STEAM REQUIREMENTS Methods of estimating steam requirements for heating various types of buildings are given in Chapter 17. - . Table 7 in Chapter 17 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 water heating can be satisfactorily estimated by using a consumption of 0.0025 lb per' (day) (cu ft of heated space) for office buildings, without restaurants, and 0.0065 lb per (day) (cu ft of heated space) for apartment buildings. Complete information on water heating' requirements is given in Chapter 48. . 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. RATES Fundamentally, district heating rates are base4 upon the same princi ples as those recognized in the electric light and power industry, the main object being a reasonable return on the investment. However, there are. other requirements to be met: the rate for each class of service should be based upon the cost to the utility company of the service supplied, and 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). 628 CHAPTER 28 1952 Guide 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. Straight-Line Meter Bate. The price charged per unit is constant, and the con sumer pays in direct proportion to his consumption without considering the differ ence in costs of supplying the individual customers. 2. Block Meter Bale. 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 customers having a high load factor (relatively low demand), and those having a low oad 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, bo the high demand customers are benefited at the expense of the others: .. 3. Demand Bates. These refer to any method'of charge based on a measured maximum load during a specified period of time. The./Jot 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 rate 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 charge based upon the demand, either estimated or measured. () A charge based upon the amount of steam consumed. This rate may be modified by dividing the quantities of steam demanded and con sumed into blocks charged for at different rates. '. The Doherty rate is divided into three elements: / (a) A charge based upon demand. (6) 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 Hopkinson 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. CHAPTER 29 . CENTRAL SYSTEMS FOR AIR CONDITIONING Features of Systems, Zoning, Apparatus Dew-Point, 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 ing 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 of outside air, is interlocked with the return air damper C in such manner that 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 more detail in Chapter 33. The cleaned air passes to the equipment that changes its temperature and humidity. Except in very warm climates, a heating or tempering 629 630 CHAPTER 29 1952 Guide coil F is required to warm the air to a temperature above freezing. Usu 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' Central Systems for Air Conditioning 631 Various methods-are practicable for controlling the temperature, hu midity and air- movement in various rooms or zones. A measure of con-: tool is attainable merely by proportioning the flow of air to each room, though usually such control by throttling dampers is difficult to maintain and should be avoided when possible. '- Another scheme is to install a properly proportioned coil in the branch air supply duct serving each room 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 WEATHER TEMPERING COIL HEATING COIL RETURN AIR / yHUMIDIFIER \ ONE OF SEVERAL DUCTSMIXING OAMPER Fig. X. Arrangement of Equipment fob Year-Round Air Supply System its tubes, or the surface may be cooled by a pump-circulated liquid such 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 is delivered into 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 pro hibitive. Economy is favored if the varying requirements, of numerous rooms or zones can be simultaneously satisfied by air from a single central supply system. FILTER-' \/ `-WATER TANK INTAKE DAMPER ^-ACCESS DOORS '-COOLING COIL Fig. 2. Alternate Arrangement of Equipment for Controlling Air Condition in Central' Air Supply System heat transfer devices are placed'in branch ducts for improved temperature control, mechanically circulated water gives excellent results as a heat carrier. The water usually is warmer than the air but it is possible to use water colder than the air. . . _ It is practicable also to use single central air conditioning equipment similar to that shown in Fig. 1, in conjunction with several fans, one for each room or zone. . In such cases there may be a separate reheater on the suction 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, coils, 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 by 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 deliver the air through the heating coil and through-the cooling coil to the two air pressure chambers A and B at the right of these coils. From these chambers many separate ducts, one of which is shown, each with a double-blade mixing damper, may convey the air to the various rooms. The mixing dampers, one of which is shown, are interlocked so that as the 632 CHAPTER 29 1952 Guide upper one closes, the lower one opens; selecting between them, air in the required quantity from either the warmer chamber A or the cooler one B. In cold weather no refrigerant is required in the cooling coil, and in hot weather no heating medium is circulated in the heating coil. With this scheme, the control of relative humidity in warm weather is not always sufficiently precise to meet requirements, since the untreated ah' 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. X reheater could be placed if desired, to the right of the lower coil to bring the air in the lower chamber to the-desired relative humidity. The simple arrangement of Fig. 2 is admirable in winter and, except where close control of relative humidity is important, may be acceptable in summer.' . . Another method of attaining temperature control in individual rooms with a year-round central air supply system, is to install a booster fan Fig. 3. Arrangement fob Individual Room Temperature Control with Central Air Supply System between the main air supply duct and the air delivery opening to each zone or room, as shown in Fig. 3. Air can then be delivered from the central supply fan through the main duct at some desired condition, for instance, 60 F, 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 de livered into the room, the spent air outlet is throttled in proportion. In many large installations this principle is applied successfully for zoning different stories in multi-story office buildings, the main supply fan being on the roof, and each booster fan used for supplying the rooms of one orientation 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 coils located in the ducts may be used. In some cases where general recircu-. Central Systems for Air Conditioning 633 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. - . APPARATUS DEW-POINT In ordinary practice, with commercial apparatus, complete saturation of the air is seldom obtained. Four-row finned cooling coils contact ap proximately 80 percent of the air, whereas six-row finned. coils contact approximately 95 percent of the air. In spray type dehumidifiers of good 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, 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 percent of the. air. For a given room load, the same apparatus dew-point will be required whether the cooling appliance contacts all the air or only 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 below the dew-pomt temperature produces two effects: 1. The air quantity which must be passed through the dehumidifier must be in creased. ; Thus, if 20 percent of the air passing is contacted, then (20 4- 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 may change the sensible heat factor. If return air only is passed through the dehumidi fier or if room air only is by-passed, the room load will not change, but if some outside air is passed through, the room sensible heat gain and room latent heat gain will be changed due to the addition of untreated outside air, which changes the sensi ble heat factor. When a load calculation is made, it is necessary to know the per centage of air affected in the dehumidifier, and calculation must be made accordingly. If the ventilation air is drawn through the dehumidifier before it goes into the room, only, that portion of the air not saturated must be included in the room load for the purpose of determining the apparatus dew-point and supply air 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............................... 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 634 CHAPTER 29 . . , 1952 Guide "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 tp that required to bring the dew-point temperature 6f 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 introdiiced 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.. . . . .. COOLING LOAD The method of determining the cooling load for a conditioned space or spaces is outlined in Chapter 12. 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 lie 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' only large enough to handle the average:maximum.' If a system employ ing zone recirculating fans and a single central-fan and.dehumidifier were used, the :saving would be reflected in the capacity of. the central fan and dehumidifier. Another example of this' diversity is' found in an. office building having restaurants and stores of-certain types in-the first story and basement. At noon, when the restaurants and stores are crowded, the offices are below normal occupancy. T. ^ - . Y- 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, having been warmed by the sun, may radiate heat long after the passing Central Systems for Air Conditioning 635 of the stin, 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 ari 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 31): There will also be some heat gain to the 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 11. 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 conditions when there is but the merest fraction of normal occupancy, and when there are prac tically no fights, 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 or 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- 636 CHAPTER 29 1952 Guide ,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, and 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, low supply air temperatures result in larger heat gains to the air passing through the ducts, as well as in poor control. Too high a supply air 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 Central Systems for Air Conditioning 637 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 30 for further discussion of the most satisfactory design difference between the entering air temperature and volume in relation to the desired room condition. INDUCTION CONVECTORS--LOW PRESSURE TYPE _ Induction Gonvectors 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 a grille at the top of the convector. Heating coils are located in the second ary aor 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. An 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 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. 638 (CHAPTER 29 1952 Guide Selection' of induction convectors should be made with due regard tir 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 rom the room through coils located in the secondary air stream and supplied with chilled water in slimmer and with hot water in winter. The chilled water removes a large portion of the sensible heat in slimmer and the hot water supplies the sensible heat loss in winter. The primaiy air is delivered at a sufficiently low dewrpoint 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 primaiy 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.. . Central Systems for Air Conditioning 639 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 is relatively great, it may be possible to replace mechanical refrigeration, or other cooling sources, and use the evaporative cooling effect- A well designed air washer using recirculating sprays will reduce the entering dry- bulb temperature to within a degree or two of the entering,wet-bulb condi tion. Thus, it may be possible that, with air entering at lOO 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 iow 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. .All of these remarks with regard to evaporative cooling are based on the assumption that all 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 wells 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 640 CHAPTER 29 1952 Guide -may be used down-stream from the unwetted coil. Saturation or partial saturation after the coil will 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 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 in the 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 collect 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. . Central Systems for Air Conditioning 641 Fans operate at full 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 - liquid, this liquid should contain some anti-freezing substance such as , ethylene glycol. If hot water is employed in cold climates, the temper-' ature control of the air should be obtained through use 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-distri, buting-tube coils or mechanically circulated water coils are satisfactory in such cases, and throttling valves may be used. Refrigeration equipment must be carefully selected to satisfy the partic 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 642 CHAPTER 29 1952 Guide spaces that are otherwise usable should be charged against the system as an operating cost. In general, the apparatus should be arranged to have 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. 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. Where 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 byTpass, 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. Central Systems for Air Conditioning 643 . The location of the complete apparatus assembly, including the dehumi difier, 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 lines 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 exceed ingly important that water-tight drained floors be provided under all overhead cooling systems, since water condensed out of the air generally will be present and may damage the interior finish of the rooms below 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 filter, 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. 644 CHAPTER 29 1952 Guide 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 quantity. 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 30 AIR DISTRIBUTION Standards for Satisfactory Conditions, Definitions, Mechanics of Air Distribution, Outlet Performance, Types of Air Outlets, Outlet Location and Selection, Directional and Volume Control, Return and Exhaust Intakes, Specific Applications CORRECT air distribution contributes as much or more to the success of a forced air heating, ventilating, cooling or air conditioning system as does any other single factor. An air conditioning system may deliver the required quantity of conditioned air and still fail to give satisfactory room conditions because of poor air distribution. The scope of the chapter is limited to the air distribution within the conditioned space. Reference is made to the distributing duct system only insofar as it affects the per formance of the air distribution outlet. (See Chapter 31 for information on air duct design). STANDARDS FOR SATISFACTORY CONDITIONS The object of air distribution is to create within the space the proper combination of room temperature, air motion and humidity, whether by cooling, heating or ventilating. The purpose to be accomplished deter mines the factors to be controlled. For instance, in many industrial ap plications it is necessary to maintain proper standards throughout a large portion of the space; sometimes almost throughout the entire enclosure. In these cases design room temperature, room , air motion and humidity will depend entirely upon the requirements of the product and its manu facturing processes. If, however, comfort of the occupants is the principal objective, con sideration of the occupied zone (floor to 6 ft above floor level) is primarily required. In order to obtain comfort conditions within this zone, standard limits have been set up as acceptable effective temperatures. This term comprises air temperature, motion, humidity and their physiological effect on the surface of the human body. Any variation from accepted standards of one of these elements may result in discomfort to the occupants. The same effect may be caused by lack of uniformity of conditions 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 dif ferent locations, or too rapid fluctuation of room temperature or air motion (gusts). 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. With, reference to permissible room air motion it is not possible to estab lish a specific standard covering the entire complex problem of air distribu tion. Velocities less than 15 fpm generally cause a feeling of air stagna tion, whereas velocities higher than 65 fpm. will disturb loose paper sheets 645 646 CHAPTER 30 1952 Guide on desks and may result in a sensation of draft. Air velocities of 25 to 35 fpin in the occupied zone are most satisfactory, but air motion of 20 to 50 fpm will usually be acceptable, particularly when the lower part of this range of velocity is used in cooling applications, and the higher values on heating jobs. In any case,,it is certain that the effect of room air motion on comfort or discomfort depends on air temperature and direction as well as on velocity. Reference should be made to Chapter 6, Physiological Principles, for information on effective temperature and comfort zones. Material in Chapter 40, Sound Control, covers acceptable room noise levels and noise generated by air outlets. 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 Intake: Any opening through which air is removed from a space which is being heated, or cooled, or humidified, or dehumidified, or ven tilated. 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. A supply grille discharges air axially with a limited spread.. 6. Register: A grille equipped with a damper. 7. 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 the portion of a grille, bounded by a line tangent to the outer edges of the outer openings through which air can pass.- 9. Mean Area: The total of the core and free areas divided by two. 10. Percentage Free Area: The ratio of the free area to the core area expressed in percentage. _ 11. Aspect Ratio: The ratio of length of the core of a grille to the width. - 12. Vane Ratio: The ratio of depth of vane to shortest opening width between two adjacent vanes. . 13. Plague: 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 thereby effecting its mixture with the room air. . . 15. Primary Air: The air delivered to the outlet by the supply duct. 16. Induction: The entrainment of room air by an air stream. 17. Internal Induction: The induction of room air drawn into an outlet by the primary air stream. (Commonly called aspiration.) . 18. External Induction: The induction of room air by the air stream discharged from the outlet (commonly called secondary air motion). 19. Induced Air: The room air entrained by the primary air through internal in duction, or by the discharged air through external induction or both. 20. Total Air: The mixture of primary air and induced air. 21. Induction Ratio: The total air divided by the primary air. 22. Throw {.Blow): The horizontal or vertical axial distance an air stream travels on leaving the outlet (grille) to a position at which air motion reduces to a maxi mum velocity of 50 fpm. . 23. Drop: The vertical distance, the lower edge of a horizontally projected air stream drops between the outlet and the end of its throw. 24. Rise: The converse of drop. . 25. Envelope: The outer boundary of an air stream moving at a perceptible ve locity. Air Distribution 647 26. Spread: The divergence of the air stream in a horizontal or vertical plane after it leaves the outlet. 27. Diffusion: Distribution and mixing of air within a space, accomplished by an outlet discharging supply air in various directions and planes in order to effect the desired air conditions in the occupied zone of that space. 28. Radius of Diffusion: The horizontal distance from the diffuser outlet to the perimeter of the space, within which effective diffusion is accomplished and air mo tion in the occupied zone is reduced to 50 fpm maximum. 29. Outlet Velocity: The average velocity of air emerging from the outlet measured , n the plane of the opening. . 30. Terminal Velocity: The average air stream velocity at the end of the throw. ' 31. Temperature Differential: Temperature difference between primary and room air. . 32. Temperature Variation: Temperature difference between points of the same space. MECHANICS OF AIR DISTRIBUTION In the mechanics of air distribution, two major problems are involved: (1) complete mixing of the primary air and air outside of the zone of occu pancy in order to reduce the temperature difference and air motion to acceptable limits before the air enters the occupied zone; and (2) counter action of the natural convection and radiation effects within the room. The theory concerning the distribution of conditioned air within an en closure is still incomplete, and no general law governing outlet performance has been formulated. The characteristics and performances of the various existing types of outlets must therefore be evaluated largely by experimen tal work. Some progress has been made concerning the theoretical analy sis of the characteristics of a primary air stream discharged in an uncon fined space, t.e., a space large enough so that the primary air stream is not disturbed by contact with surfaces, or by adjacent streams. The approach' to this problem is usually made by means of the momentum theory. De velopment of this theory has so far been confined to side wall distribution of air, because this is its most elementary application. Fundamentally, the same laws apply also to ceiling distribution, but a great amount of addi tional research is still required to adapt them to the more complicated conditions of deflection of air up to 90 deg, spread up to 360. deg and the re sulting rapid induction. Momentum Theory . When air is discharged from an outlet into a free open space, the primary air stream entrains room air as it traverses the space. This entraining effect increases the cross-sectional area and reduces the velocity of the resulting air stream. When the air stream is projected horizontally, in duction takes place with the conservation of linear momentum. This has been confirmed by tests which indicate that the momentum remains al most constant throughout the entire measurable length of the air stream. This relationship may be expressed by Equation 1: , ' where M,Vi + MtVi = {Mi + M,)V, (1) Mi = mass of primary air. Mt mass of induced air. 648 CHAPTER 30 1952 Guide. V, velocity of primary air. . Vt = velocity of induced air (for practical use, Vi -- 0). Vi = velocity of the mixture. . If the velocity of induced air is zero, Equation 1 changes to MiVi = (Mi + MJV, .' Vi Mi + Mi or, V, ~ Mi ~T ' (2) Since in many applications the densities of primary and room air are about equal, air volumes may be substituted for mass and Equation 2 becomes . V\ = Qi + Qi = Qt V, Qi Qi where .... Qi = volume of primary air, cubic feet per minute. . Qi -- volume of secondary air, cubic feet per minute. . Q, = volume of mixture of primary air and induced air, cubic feet per minute- r = induction ratio. ' ` Jet Pattern from Round or Rectangular Openings in a Large Room The relation between the shape of the discharge of a jet and the shape of the conventional outlet has long been the subject of research. It has been proved to be incorrect to assume that the jet retains the outlet shape when it discharges into afree- open space.1 Air streams from rectangular outlets having low aspect ratios develop a symmetrical or cone shape within a few-diameters from the nutlet face. From there on, the jet continues to expand at a fairly constant rate. Beyond 20 diameters there is very little difference between round and rectangular jets. The. assumption can'be made that the apex of the cone is in the same, position for any jet having a small aspect ratio. For the more usual problems of the conventional room with outlets near the ceiling, there'are insufficient experimental data to justify a definite statement on the effect of aspect ratio. If the round or rectangular opening is divided into a number of orifices having straight sides, the performance of the air stream will be similar to that of a plain opening. . Velocity Across Jets Results of many tests1 indicate that the ratio of centerline velocity to average velocity is about . 3,: irrespective of outlet size, shape or initial velocity. This statement is true for stream cross-sections located beyond 10 diameters from the outlet, and is fairly accurate for distances up to 50 diameters. , Experimental data are lacking for distances beyond 50 diam eters. . Effect of Aspect Ratio on Entrainment In slotted outlets, the air entrainment of the primary jet is a function of aspect ratio.1 This effect is most pronounced when large changes in the ratio are made. A comparison between a slot of aspect ratio 24 and a square opening of the same area is given in curves A and B of Fig. 1. At Air .Distribution r; ;;; 549 a distance of 8 ft from the outlet, the entrainment of the dot is 8.1 as conP parec^ with 6,9, for.jlhe. square, ;or an.increase, of about 17: percent,; .ipurY;P .the: furtimruncreasejin entrainment ;ob.tainet} by usihgiap aspect r%fe.qf,48,; ,^An&incre^eLtA0 percent is obtained over; the. 1 in. slot. This indicates that long narrow slots produce air ;streams that give high, induction of secondary air.., .. ... <.)>,. ` Parallel Slots . . ' ... The use of several slots in 'parallel to vary the rate of air entrainment depends mainly on the distance between the slots. If close together, the air pattern is about the same as for a single opening of equal area. Spac ing-the openings farther apart gives an increase in entrainment as shown on cqryes I) and E of Fig.-l. It will be noted .that 2 pjpenihgs 24,'ih, x J in.; located Very close together will obtain.an entrainment, which isabout the same aS ObtAihed with brie 24 in. x in. opening. However, if the slots are' spaced 6 in. apart there is a marked increase in entrainment. 650 CHAPTER 30 -1952 Guide t ' * -Throw: Equations'for the throw of straight flow side wall outlets have'been'die-! veloped- on' the! basis of the momentum theory. -Equation States ihe throw in terms of the'area of the outlet and the primitry airvblumel3 ' " : Qi L = 0.83 -^= .. VAi where \ -.t.:1-.-;-'-.-......~j L = throw, feet: . ; '. .. Ai = effective outlet area, in square inches = (gross measured area) X (percen tage of free area/100) X (discharge coefficient). ; The discharge coefficient is. approximately 0.8. ............ ' Equation 4 has been developed.under the assumption that the tempera ture of the supply air is the same as the temperature of the room air. It applies only to straight;flow": .outlets with aspect ratios'less than 16. Equation 5 for the performance , of. straight flow outlets evolved from research1 allows, the calculation of the maximum residual velocity at any distance perpendicular to the-.outlet-face. It applies for aspect ratios up to 50. - : '. ' : - ' i :' ' : V ' 7T rr ... (5) where V, = maximum residual velocity in air stream, i.e., the highest maintained ve locity at the given cross section in'the room, feet per minute. Vi = average initial velocity across outlet, feet per. minute. . K = constant of proportionality. ' Ai = effective outlet area in square feet = (gross measured area) X ^(percentage of free area/100) X (discharge coefficient). . ! X = normal distance from outlet face, feet. : Equation 5 together with Equation 6 (which reduces to Equation 7 if the jet angle is 20 deg) for the entrainment'ratio',"' where Entrainment Ratio = ( A/ + 2X tan - j -- .. RXVA\V 0.785 . .. ?) (6) R =, ratio of maximum residual velocity to average residual velocity. 0 = jet angle or spread angle in degrees. . - . - - . . .-. _ Entrainment Ratio = (A/ + 0.35 X ) --' 1'' ` (7) . 20:deg jet angle)- BXy/,Ax .0.785 ./ . i has been used to develop, charts3 which provide the graphical solution of problems involving the determination of the throw of air from'dots and,jets, the residual velocity,, arid .the size of openings. (See Figs. 2 and 3). The charts, apply only to .air 'discharging into room, air of same temperature as the stream. - They can be used to determine the throw of. air and entrainment Air-' Distribution 651 ratios up to 40:1 with initial velocities of 1000 to 6000 fpm, and with resid: ual velocities of-100 to 1000 fpm. The charts furthermore are for "use with sharp-edged orifices or slots, and include.the coefficient of discharge. .If,air is discharged from an orifice with a well-rounded entrance or from a length of straight duct, the coefficient of discharge is unity and the .'actual area of the opening is the effective area. For such rectangular openings the ef fective diameter is the diameter of a circle with an area equal to the actual with;an initial velocity of 2000 fpm.. Determine the maximum residual velocity and the entrainment ratio at a distance of 15 ft from the slot. '- From Fig. 3 the effective diameter = 6.2 in. = 0.52 ft.: The number of effective diameters in 15 ft f 15/0.52 = 28.8. '. From Fig. 2 at 2000 ft initial velocity read entrainment ratio =6.6 and maximum residual velocity = 390 fpm. From tests.it has been shown that the average residual velocity may be taken as 1 of the maximumor 130 fpm in this case. Example 2: Using the data from Example 1 determine the distance at which the maximum residual velocity will be 150 fpm. . .... ........ . From Fig. 2 at Fi = 2000 and V, = 150, the number of effective diameters-is read directly as 73 and the throw of the air is therefore 73 x.0.52 = 38 ft. ..; Example S: Air issues from a round orifice plate with an initial average velocity of 4000 fpm. It is to have a maximum residual velocity of 400 fpm at a distance of 30 ft from the opening. Calculate the size of the opening required and the entrainment ratio. .. . On Fig. 2 at the intersection of the curve of.4000 fpm, the entrainment ratio is. read directly as 15 and the effective diameters of throw = 55. ' " - 652 CHAPTER 30 rJ.952Guide /Since 55 effective diameters are equal to 30 ftr as required; .1 .effective diameter = 30/55.= 0.545 ft or 6.56 in. ' . . . , ..... ... ; . On' Fig. 3 vertically below intersection of 6.56 in. effective diameter tine, and equivalent round opening line; read 8.5 in. in lower margin. : '' ` ' Example kv:A jet of air issues fromapipe or from air orifice having awelbrounded Air Distribution 653 ured'and found to be-between 14 and'25 deg; The angle will depend on the- type of approach, type of outlet and< velocity. '- - The effect of vertical bars placed in the face of the outlet to increase, the spread, may also be deduced from the momentum theory. Assuming that , there .are ho horizontal deflecting bars; and that the air spreads vertically through a total wangle of (14 - deg; that a uniform velocity exists at; any ec- tion -of the air stream; and that.the conservation of;momentum .principle applies- down'to a:velocity: of 60 fpm ; the. following approximate equations for throware to be substitutedlfor Equation.4;2 ; . : ; For a spread of 15 deg oh each horizontal side L 0.55 yi-- ' v Ai (8) For a spread of 30 deg bn each'horizontal side L = 0.37 Va, (9) . For a spread of 45degon each horizontal side Z. 0.28 0. y/,A (10) entrance (coefficient of discharge 1.0) and delivers air with the same velocities and with the same throw as.in Example 3. What is the required diameter? ` : : In this case since the coefficient of discharge is unity, the effective diameter ofthe jet is the actual diameter of the pipe or orifice, or 6.56 in., as obtained in Example 3 Spread . The induction effect results in the spreading of the air stream. The total angle included by the air stream from.straight flow outlets has .been .meas- Guide Vanes -. .. '. .' ^ ^. Vanes should have a depth of one to two times the'spacirig between the vanqs. If the ratio, of vane depth to spacing is less .than, one, effective con trol by means of the vanes cannot be obtained: Little improvement is ob tained by increasing the' ratio, beyond two. The effect' of various, types df vanes is given in following paragraphs. .. , .. .. Straight Vanes. As mentioned previously, the included angle.between both planes will be in the neighborhood of 14. deg, for a straight setting of the varies aS shown in Fig. 4. ,. Diverging Vanes. Such vanes set'for an angular spread will have a marked effect on the direction and distance of travel of an air stream. An outlet having vertical . vanes set straight forward in the center, with uniformly increasing angular deflection to a maximum at each end of 45 deg, will produce an air stream with a horizontal included angle of approximately 60 deg as shown in Fig. 4. The throw -will be re duced one-half for such a.vane setting... Increasing the divergence of the vanes reduces the air quantity handled by an outlet, for'S:'given duct static pressure. The primary function of the vanes is to spread the air. horizontally. Spreading the air vertically entails the risk of hitting warns of other-obstructions,'or of blowing pri mary air at excessive velocities into the occupied zone;; ;....... ! ' ; Converging. Vanes. The blow of an outlet may be somewhat increased by converg ing the vanes of an outlet as illustrated in Fig. 4. Even with converging vanes, the resultant angle of spread of an air stream will not'be less than 14 deg. The air con verges for a few feet in front of the outlet, and then diverges more than if the vanes had been set straight. = - Both the horizontal arid vertical vanes of an outlet are important; After an installation has been made, many ` conditions of draftiriess or stuffiness 654 CHAPTER 30 -1952 Guide can be alleviated by some vane adjustment, provided an independent means for regulation of static pressure behind the vanes is included--<>!;.>- ;v Vertical Drop and Rise . , :The distance that thelower edge of the air stream drops below the bottom of the outlet is important, since the air stream should not reach the occupied' zone until the velocity has fallen to. about 50 fpm. : The drop: (H, feet)'is influenced by two forces; the natural vertical spread of. the stream and;the gravitational force due to the difference in density between supply air- and room air. For air emerging at room temperature, the drop will be a func tion of the spread only and will be equal to: . , :, : ...... . r g,,tXl,n(Spread2AnglC) (ID where ;-J5Ti = drop due to spread (when emerging air and room temperature are the same), feet. / L -- throw, feet. When there is a temperature difference between the air stream and the room, there is an additional drop which, is approximately:4,; Hi -- ni(tr -- r,,)L"i (12) where ' Hi = additional drop due to temperature difference, feet. rii and rii = constants (tentative suggested values i = 5, n, = 1.2). tt = room temperature, degrees Fahrenheit. ., Ut = supply air temperature, degrees Fahrenheit. , .. Vi = jet,1velocity, feet.per minute. . ... i : , i . "' .- ,It should be remembered,'that the total'drop H = Hi + Hz- \Hi'is positive for either heating or cooling; Hz is positive, for cooling, negative for'heaitihg. In corisequence, there will always'be vertical'drop in coqllng, and a vertical rise in heating only if Hz > Hi.: '' . ~ ''" 7: Another empirical'equation for the total drop is? " where m(tr -- i,,)L H= Ui. . ... . (13) ' ro'= . constant, (tentatively suggested value of m = 16). . .. .' In other`words, for a given throw L, the drop or rise increases as the tem perature difference increases andthe outlet velocity decreases. This,equa tion is only valid if a temperature difference exists between room air and supply/air.. . :: Room Air Motion (Wall Outlet) ...One.If the most important, problems in air distribution is to achieve air motion in the occupied zone within acceptable velocity limits., . Therefore, Air .Distribution 655 outlet performance and characteristics of. the space have to be related to this air motion. . '' 'Theair moving in the occupied zone is (for a side wall outlet) equal, in quantity, to the total air contained.in the, outlet stream at the. end of .the throw,'and it is generally moving in a direction opposite to the stream; Assuming that the maximum volume of air is in circulation when the air stream velocity Fj drops to 200 fpm, that the free area for return-flow is 0.6 of the area of the wall in.which the outlets are located, .then, according to .the momentum theory:2-4 . . -- .. , ,. Q. 0.6 x A (14) where. V = .average room velocity, fpm. . ... Qi volume of room air in motion, cfm. " A<r = area of wall in which outlet is located, square feet. ' : . ' .` y. Since Q3 = Qi x r, (by definition); and r = according to Equation 3; __ V.3 . . ' . . the average room velocity is: .. __ . ............ ..... > = ^ =_9> 0.6A. 0.6AW\F,/ or, with Vs = 200_fpm., ............. ; . F = QiF, 120A, ' . (15) When the: volume Qi; of primary air, the velocity Vi, of primary airland the wall area A,,, are known, the average room velocity may be calculated from Equation 15 in order to determine the acceptability of the air dis tribution system. " ' ' '' . - :- OUTLET PERFORMANCE The factors of*, outlet performance, (1) throw, (2): drop, (3) room', air motion, (4) capacity, (5) temperature differential, (6) dirt and (7) noise, place considerable limitations on the design of a satisfactory distribution system. . '. . . .. , . .. '. . : ' .. ' 1. Throw. The throw of a wall outlet must be sufficient to produce satisfactory . conditions over the. area to.be conditioned. , Underblowing may eause heated air to rise too rapidly above.the occupied, zone and thus create excessive vertical temper ature variation (stratification);,in cooling operation it may cause cold air.to drop into the occupied zone before a satisfactory mixing of,supply and roOm air has been accomplished by.induction and;thereby create a condition of.acute discomfort (draft). On the. other hand, overblowing.will result in objectionable downdrafts from any surface the primary air; stream may strike. . . . . < . ' - On the average, it is considered most practicable to select a throw which is threefourths of the distance toward an exposed wall or window, as shown in A. of Fig. 5. However, structural characteristics, mounting height; temperature differential and resultant drop or rise,'or location of greatest heating or cooling loads strongly affect the selection of. the optimum throw. In spaces with beamed ceilings, the outlets should be located below the bottom of the lowest beam level, and.preferably'ldw enough so that an upward or arched blow may be employed. The blow should be arched sufficiently to miss the beams and, at the same time, in such a manner as to 656 CHAPTER 30 1952 Guide prevent the primary or inducedair stream from striking furniture and obstaclea, and producing objectionable drafts. . In the case of ceiling diffusers, air is .distributed with a,horizontal spread, of .360 deg. In addition there is a downward component of air: motion. Therefore, both: throw (radius of diffusion) and mounting height are important and interdependent factors. Due to the 360 deg spread of air diffusion, the rate of induction will be higher, and the throw shorter, than that of a wall grille opening handling the same air.quantity at the same outlet velocity. Therefore, ceiling diffusers will, frequently .permit the use of higher air velocities .than wall outlets., and consequently.may be sized smaller, to handle the same air volumes.' If such beiling outlets are installed flush with the' ceiling, impingement of the air stream along the ceiling surface restricts'induction of secondary air, and the throw is increased approximately 20 percent above that of an unrestricted air stream. '. In the use of perforated ceiling plates as air distributing devices, the term throw could hardly be applied in its proper meaning. Although this type of outlet can handle the greatest amount of air in proportion to room size, jet velocities must be kept low. In all types of ceiling air distribution the following should be noted:. ' If cold air is used, it must be brought to the proper temperature by mixing with room air before entering the zones of occupancy. : . .Air slightly above room temperature will usually be properly .distributed by out lets selected for cooling. . ' ' ... .. : .When delivering warm air the same may be projected downward, and the amount of dispersal of the jet varied to obtain proper mixing and control., . - 2. Drop. The outlets should be located so that the air stream at the termination of the blow is not less than 5 or 6 ft abdve the floorleyel. As illustrated in B of Fig. 6 the maximum permissible blow for a given ceiling height may be obtained by locat ing the outlet low on'the wall, arching the blow, ,andaweeping .the air across the flat ceiling.. -The air, as.it traverses the room,,will adhere,to the ceiling., The objection to this methodis the possible streaking of the ceiling with dirt. : ' V 3. Room Air Motion. Various features may cause room air motion to exceed ac ceptable standards. Some of these are: excessive air discharge velocities; high air volume per cubic foot of space (often referred to as number of'air changes per hour); premature drop of cold air into the occupied zone j'.overblow causing Spilling of high velocity air into the occupied zone; heating in severe climates1 by means of downward projection of hot air. It should be realized that these factors will not equally affect all types or designs of outlets at different temperature differentials; mounting heights; etc.' For instance, certain outlets may safely handle mOre air per cubic foot of space at higher discharge velocities than-others, and-downward'projection of Supply air will sometimes not be considered excessive if the Supply air temperature is sub stantially higher than the.room temperature. -, . ,. ' 4. Capacity. The. quantity of air to be; handled is'determined by the .heating, cooling, or ventilating requirements. 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 used should be carefully noted to make certain that resulting velocities are suitable for the application.' > Air Distribution 657 5. -Temperature Differential. This is one of the most important factors affecting outlet performance. The quality of the temperature control, or the extent of the control problem, is directly a function of temperature difference: Obviously, a- system which carries under design conditions only a 5 deg difference between supply air stream and room temperature, would require no control at all, for even a 50 per cent change in load could only effect a 2 deg change in room temperature under the worst conditions. Because of the self-equalizing nature of most load factors, even this extreme is never realized'. It is obvious that the greater the temperature dif ferential Between supply air and room temperature, the greater will be .the change in: roOm temperature for a given change in load. The use of outlets that' give.rapid mixing, permits greater temperature' differentials: : These principles' apply ini both heating and cooling practice:. '. . ' ' - . . .. 6. Dirt. Although the primary air may be carefully filtered, small particles of dirt and dust will niot be captured.by mechanical filteisi.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. With wall outlets, :dirt streaking may be minimized by preventing direct impingement of the air on any ceiling or room surface- d Floor outlets may-offer objection as dirticollectors, -"'t. ' . 7. Noise: 'The increase of noise level caused by an.butlet is priijiSrily a function of its air discharge' velocity and its size.' The maximum acceptable noise level in a space may dictate completely the selection of the permissible outlet velocity. In addition, however, noise may be caused by excessive restriction of free outlet area due to outlet design; by unnecessary turbulence due to one sided air flow through the outlet ; or by the impingement of high velocity air on sharp edges. Such high fre quency noises due to excessive turbulence are especially annoying (see Chapter 40 lor discussion of permissible room noise levels ana noise generation by.outlets). TYPES OF AIR OUTLETS : Two types of air supply outlets are commonly used; side wall and ceiling. A variety of designs has been developed for both.types, and the final selec tion depends to a large degree upon the specific problems arising in the air distribution system to be used. , In addition to the comments on use and application of outlets which fol- - low, reference should also be made to sections of this chapter oh Outlet Location and Selection, as well as on Specific Applications, . Wall Outlets ;. Wall type openings in general use are; (1) perforated grilles, (2) vaned outlets, (3) registers, (4) slotted outlets, (5) ejector nozzles, and (6) wall diffusers. . . /. ' ' . ./ ' ... 1. Perforated Grilles. Due to the non-adjustibility and small vane ratio, these outlets, although inexpensiveI have not. met with favor as wall type supply open ings.. They are useful primarily where" directional air control is unnecessary, ana for return air intakes. , l' . . . .... 2. Vaned Outlets: Outlets equipped with either vertical or horizontal adjustable vanes or both are particularly suited to sidewall distribution. For proper'control over the air flow, the-vane ratio should be from 1 to 2. Outlets with non-adjustable vanes may.be employed? but they should only be used where the perfonnance is not critical or can be adequately predicted. Vanes should be properly designed to pre, vent an increase of.noise above permissible level. ." . 3. Registers. Perforated grilles or vaned outlets equipped with a vane damper are termed registers. They are used primarily for residential heating systems, where the outlet distribution is not critical and low cost is of importance. 4. Slotted Outlets. Slotted outlets consist essentially of either flat steel plates containing a number of long narrow slots, or a single long narrow slot. In order to give a good conversion from static pressure to velocity pressure, the sides of the slots gre rounded to give a venturi effect. Due to their high aspect ratio, the slotted out lets'have a'greater induction effect than the comparable vaned outlets of equal area and consequently, the throw is reduced. Tbey are primarily useful where an un: 658 CHAPTER 30 1952 Guide obtrusive means, of distribution is desired, and where it is desirable to submerge the outlets into the room decoration and to ininiinize the effect of obstructions in the line of discharge. They are adaptable to harrow rooms having low ceilings. In this case the slots should extend; the full length of the room. In all applications air quantity and distribution must be carefully, planned, as correction after installation is difficult. . . ." 5. Ejector Nozzles. These are outlets operating at high static pressure. They give a high conversion from static in the duct to velocity pressure in the outlet, and have a high induction effect due to their high outlet velocity. They are chiefly used for long throw and industrial process installations, such as drying, freezing, cooking, etc. Another type of ejector is sometimes referred to as a louver nozzle and has a 45 to 90 deg elbow, which can be rotated similarly to a universal joint about ah axis perpendicular to the surface to which it is fastened. _ These outlets give a con siderable degree of adjustability and are, therefore, desirable for use in confined spaces where spot cooling is employed. The use of very high velocities is gradually disappearing due to noise difficulties. ' 6. Wall Diffusers. These outlets incorporate design features originally developed for ceiling outlets{ and use, therefore, semi-conical or semi-pyramidal guide vanes instead of the straight vanes of the conventional side wall outlet. Ceiling Outlets Generally used ceiling outlets are: (1) plaques, (2) ceiling diffusers, and (3) perforated ceilings and panels. A discussion of each follows. . 1. Plaques.' Plaques are of simple design. The air from the supply opening impinges on a plate, which permits the air to be deflected horizontally in all direc tions. Plaques, although inexpensive, are difficult to control and are not generally satisfactory. In certain applications, a properly designed plaque yields satisfactory results. . .. 2. Ceiling Diffusers. Ceiling diffusers are round or rectangular outlets installed on, or parallel to, the ceiling, and discharge supply air in a variety of directions and planes. Performance of the different designs varies according to principle employed. Some have no internal induction, but hasten external induction Dy supplying air in multiple.layers. Others have internal induction and distribute air over an entire hemisphere. The induction effect is greatest in the direction of the axis of the outlet, and least in the plane perpendicular to the axis and located at the ceiling level. Thus the induction is greatest in the vertical direction where the least throw can be toler ated, and least in the horizontal plane at the ceiling where the greatest blow is both desired and permissible. . 3. Perforated Ceilings and Perforated Panels. These devices obtain air diffusion by discharging air through perforations in the ceiling or part of the ceiling or walls. The advantages are unobtrusive appearance, adaptability for application of sound absorbing material to the design, and large outlet areas (when desired) to limit outlet air velocities. . . .. . Some perforated panels feature a control plate frame which is inserted in the con ventional 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 veloci ties. Means are providedin all cases for distributing the primary air over the entire panel in order to obtain even air distribution and proper air velocities. . . The large outlet areas are advantageous where there is a high' room load, a high ventilating requirement, or where a low ceiling, combined with high ventilating air requirement, necessitates a low outlet velocity. This last condition may be illustrated by a drafting room with a 9 ft ceiling having a high cooling load. In this case, the air velocity at the head level of standing occupants must be barely perceptible, and consequently, the velocity from the outlets must be low in order to be dissipated in a distance of approximately 4 ft. OUTLET LOCATION AND SELECTION In selecting the location of outlets, consideration must be given to the factors of (1) physical construction, (2) physical appearance, (3) location of heating or cooling loads, and (4) outlet performance. , 1. The physical construction of a building, particularly of old buildings, immedi 'Air Distribution 659 ately .places limitations on the type of distribution system which can be employed. The first factor in the selection of outlet locations, therefore, is a consideration of the possible location of the supply duct, that is, whether it is above the ceiling, within the walls, through furred spaces above corridors, or in the conditioned space, etc. A particular method of distribution may be highly desirable, but its execution, due to the location of beams and masonry walls, may be impossible. 2. The physical appearance of the outlets should conform to the esthetic appearance of the room. In factories, warehouses, etc., the esthetic demand may not be high; however, in department stores, clubs, theaters, etc., the location of the grilles may be dictated largely by such demands. ' 3. The location of healing or cooling loads in a room dictates to a great extent the general location of the outlets. The. outlets should be located to neutralize any undesirable cold drafts or radiation effects set up by a concentration of the heating or cooling load. The problem can be divided into natural loads due to outside weather and internal heat loads. In winter the natural or primary heating load is caused by exposed walls, win dows and skylights. Heat is lost primarily through convection to these exposed surfaces. The convection currents or cold drafts drop down the exposed surfaces and seriously impair the comfort conditions in the room, particularly at the floor level near the exposed surfaces. The outlets should be located to counteract these downdrafts. Methods which may be employed are: . a. Direct counteraction of convection currents from cold surfaces can be obtained by locating the outlets to blow upward from beneath windows or exposed walls, or to blow across the exposed wall. This method is desirable in small offices or bedrooms, or any location where people are seated or working near exposed 1 surfaces. In northern climates; where the outside temperature may be con stantly below 40 F, and the construction consists of uninsulated walls and single glass, this method of distribution is particularly useful for the main tenance of comfort requirements. b. High induction by ceiling or wall outlets may be employed to nullify the con vection currents from exposed surfaces. H outside temperatures are consist ently below 40 F, and the exposed surfaces are not well insulated, the induction effort required for neutralization of the downdrafts is so great that the air motion in the room may exceed comfort limits, unless care is taken in selection and location of the outlet. Where comfort conditions are not critical as in factories for heavy manufacturing, warehouses, etc., satisfactory results can . be obtained even in cold climates. For uninsulated walls and glass areas some supplementary heating is often valuable. Wall diffusers, direct radiation or warm panels will satisfy these requirements for supplementary heating. c. The location of exhaust or recirculated air openings at the base of large areas of glass is sometimes effective in reducing cold downdraft into the occupied space. If a concentrated source of heat creating an internal heat load is located at the oc cupancy 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 latter method will prove more economical, as heat will be withdrawn at its source rather than be dissipated into the conditioned space. Where a lighting load is particularly heavy (five watts per square foot) and located high in a conditioned space, it may be economically desirable to locate the outlets below the lighting load. Warm air from the lights will stratify, near the ceiling and can be removed by an exhanst or return fan, the former being advisable if the wet-bulb temperature of the air is above the outside temperature, and the latter being pref erable if the wet-bulb, temperature is below that of the. outside air. Either method , reduces the requirements for supply air. If. the lamps are exposed, less saving can be realized than if enclosed, as a considerable portion of the total energy is radiant. 4. Outlet Performance. The laws of air distribution, previously discussed, will be found to exercise an important influence upon the design of an acceptable distribution system. This applies particularly to such features as throw, drop, capacity and room air motion. . Procedure for Outlet Location and Selection In determining outlet location and selecting the type of outlets, it is cus tomary to proceed as follows: 660 CHAPTER 30 ,. 1952 Guide f 1. Study the plan'of the building and note the amount of air to be supplied to each enclosure. . ; 2. Select number of outlets for each enclosure, considering air quantity required and distance available for throw or.as radius of diffusion. " The same factors, as well as distance from floor leveLavailable 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 space. Usually the outlets .will be evenly spaced to distribute air uniformly throughout the enclosure. Sometimes, however, more air should be supplied and directed towards zones.having exceptional heating'or cooling loads. An important point to consider is the combination of proper outlet -location and efficient, duct design (see Chapter 31). Consult manufacturers' tables for recommended location and spacing of outlets: . . 4. Select size of outlets according,to air quantity handled, permissible throat or discharge velocities or effective throw, taking into consideration other factors such as noise level, static pressure resistance, etc. It will generally be found that most selection tables for grille type, outlets are based on capacity and throw, whereas data for ceiling or wall diffusers are usually based upon capacity and permissible outlet velocity. Choice and arrangement of either type of outlet should, however, satisfy the requirements of all aspects of air distribution. Therefore, type, location ana size of any outlet should be -checked against manufacturers' ratings to determine whether the selection made would satisfy the requirements of the job: .The most important questions to be considered are: '. a. .Can drafts occur because of divergence between rated throw (radius of diffu- . .. sion) and distance between outlet and nearest obstacle of air stream (wall, - beam, pillar, ledge, etc.)? .. . - - b. Can drafts occur because of excessive cooling temperature, differential and too low mounting height of the outlet? . . . c. Can drafts occur because of too:low velocity causing a drop in cooling installa tions? d.Will the outlet operate at too high a velocity and thereby cause an excessive . . increase in noise level? . . .. . .. ' . .- ' i e. Will the outlet operate against an excessive static pressure resistance? :. Balancing the Sysem . ' In designing an air conditioning system it should'be the, aim of the en gineer to size ducts and outlets in such a mariner that proper distribution of supply air takes place. . In practice, however, this is almost impossible and therefore additional means for regulating air distribution are required, to balance the system. Some of these means are: - . - 1. Reducing the effective area of some supply openings by blankroffs. ....-; 2. Placing dampers in the supply and return (exhaust) openings. v: 3. Placing dampers in the supply and return (exhaust) ducts. 4. Using combinations of dampers in both supply and return (exhaust) ducts. : In selecting the desired type of damper or balancing method, the follow ing points should be kept in mind: . . " . 1. Unfavorable effect on air stream and noise level should be avoided. This will often eliminate blank-offs and dampers, installed in the supply and return (exhaust) openings, unless such dampers are of special dpsign. ' 2. It should be possible to alter the volume control setting and measure the amount of air handled without difficulty. This will be particularly- difficult, to achieve in the case Of blank-offs. ... : ' Generally speaking, it is most satisfactory to install dampers in the sup ply duct at some distance back of the outlets, so as to avoid disturbing the air flow. Dampers in both supply and return air ducts, form the most .flexible means of controlling supply of air to the room and static, pressure within the room. Means of volume and directional control are discussed in Air::Distribution 661 detail in a following section of this: chapter.. Many types of air distribution control devices are now commercially available: ' . , - DIRECTIONAL AND VOLUME CONTROL Duct Approaches to Outlets ^ In order to obtain proper direction of flow arid distribution; of air from outlets, it is necessary that the air stream approaching the outlet ,be of uni form velocity over the entire, connection to duct, and perpendicular to the face. . ... .;... . ' - '. .. . Grilles and directional outlets cannot compensate for improper approach. Any attempt to secure a low face velocity and a high duct velocity by cori- TT % V r E. 0 .600 FT PER MIN F. Fig. 6. Outlet Velocity and Air Direction Diagrams for Stack Heads with Expanding Outlets Stack 14 in. x 6 in. Outlets 14 in. x 9 in. Stack Velocity 500 fpm _ . A. Rounded Throat and Rounded Back. D. Square Throat and Cushion Chamber. B. Square Throat and Round Back. E. Rounded Throat and Back and 2 Splitters. C. Square Throat and Back. ` ': - F. Square Throat and Back and 6 Guide Vanes. , '' * structing an expanding chamber directly behind the grille, is likely to be un- successful because the enlargement angle, even in a straight duct, cannot be greater than 7 deg at each side . if the stream is to fill,the outlet without turbulence. . . ., In elbow outlets or stack heads at the top of vertical stacks, it is necessary to provide splitters or. guide vanes in the elbows 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. The direc tion of flow, distribution and velocity (measured 12 in. from outlet) of the air, based on tests,6 are shown in Fig. 6 for various types of stack heads ex panding from a 14 in. x 6-in. stack to 14 in. x 9 in. outlets, without grilles. The air velocity for each Was 500 fpm-in the stack below the elbow, but the direction of flow and the distribution patterns are generally indicative of 662 CHAPTER 30 - 1952 Guide i v perforinance obtainable with non-expanding elbows of similar shapes for a range of velocities 200 to 1400 fpm. Some of the conclusions drawn from the tests were: ^ 1. Experiments with various elbow outlets on the 14-in. x 6 in. vertical stack5 with stack air velocities of 200 t<>1400 fpm, indicated that enlargement of the outlet area, whether used in connection with square or rounded elbows, would not reduce either the angle of discharge (which was 20 to 30 deg above the horizontal) or the outlet velocity. The effect: of the enlargement of the.putlet was mainly to increase the reverse flow area in the lower part of the outlet, but in each case enlargement of the outlet reduced the static pressure in the duct below the'elbow. ' 2. Splitters in the elbows had the effect of dividing the air stream into a number of streams' flowing through rounded elbows, and therefore lowered the angle of dis charge, reduced or eliminated the reverse flow area, and made the outlet velocity quite uniform. : , .... : _ 3. Turning vanes having 2 in. inner and 1 in. outer radii located in the center of the elbow were found most effective in improving performance in regard to angle of discharge, outlet velocity, and elimination of reverse flow area. Fig. 7. Effect of Various Dampek Arrangements Designed foe Straight Blow 4. Pressure loss through stack heads may be reduced by use of splitters or turning vanes, or by increasing the inner radius of an elbow. Considering the sum of the velocity and static pressure as a measure of the energy required to change the direc tion of the air stream and to deliver the air into the atmosphere, and considering the energy required for a plain fitting as 100 percent, it was found that turning vanes dropped the energy requirement of square type stack heads to 45 percent. Splitters reduced the energy requirement to 90 percent in long radius elbows, and .to 74 per cent in short radius turns. In expanding heads, splitters reduced the energy require ment to 58 percent. - . , ,; Side Outlets in Horizontal Air Ducts .. . When air is supplied to a room from side outlets in horizontal ducts, it is necessary to use directive devices within the duct at each outlet in order to obtain a uniform velocity of delivered air, and to obtain a direction of flow perpendicular to the face of the Outlet. In tests6 conducted with 3 in. x 10 ini,!4 in. x 9 in., and 6 in: x 6 in. outlets in a 6 in. x 20 in. horizontal duct at duct velocities of 200 to 1400 fpm (in the 6 in. 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 therefore not found to be desirable. Ceiling Outlets on Horizontal Ducts 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 it- Air Distribution 663 self. The shorter the connection between bottom of duct and outlet, the greater is the need for directive devices to obtain uniformity of flow. - Gen erally 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 if the ducts are shallow and the connection areas are compara tively large. This will be the case when more than one outlet is installed on one duct run, and restrictions of duct area 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 Table 1. Recommended Return Intake Face Velocities Intake Location Dnnr nr wall Innvprs ' , . Velocity Over Gross Area Fpm 800 up 600-800 400-600 500-700 600 of them however permit a range of adjustment from maximum air supply to complete shut-off. When selecting type and location of such dampers, the following points must be considered, especially when the volume control feature is to be located near the air outlet itself: (1) deflection of air stream by the damper; (2) need and feasibility of directional control; (3) increase of noise level due to irregular and localized high air velocities caused by damper operation. The following types of volume control are most frequently encountered: : 1. Slide Damper. A.single plate which can be pushed across the duct. Since its operation changes the free area of air passage in a one-sided manner, it should not be located:near any air outlet, and its.use is practicable only where no intermediate setting between full open and-closed is required. .. . . 2. Hit-and-Miss Damper. Two slotted plates or discs, closely adjacent; by moving one of the two plates the 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. . . ' .. i Splitter Damper: A single blade sheet metal plate-hinged at one edge, usually located at the branch connection of a duct or outlet.. It is easy to operate, but often -causes irregular air flow in the duct. When used in connection with, and near an. outlet, additional directional control is required. . 4. Buiterfiy Damper. A single blade sheet metal plate hinged in the middle, usu- slly located in a straight duct run. It is easier to handle than a splitter damper, since only half the motion is necessary to change its setting: However, if located too close to an air outlet, it is objectionable because its operation frequently results in a 664 CHAPTER 30 1952 Guido 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. 7). ' 5. Louver Dampers. Numerous designs have been developed incorporating a. series of splitter or butterfly dampers across the duct or air. outlet. Their main advantage consists in. retaining greater uniformity of air flow, and in requiring less depth for installation. Some designs provide for louver blades moving in opposite directions, and while decreasing free air passage area, retain a constant air flow direction along the axis of the duct air outlet connection (see A and B in Fig. 7). ; 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 effect of air flow through return intakes upon air movement in the room is slight. Air handled by the intake is drawn from all directions, the velocity dropping off rapidly as distance from intake increases. The only locality where drafts may prove objectionable is adjacent to the intake. To prevent ex cessive airmotionin this areadue to the return intake,itis advisable to compute the total air motion toward the exhaust opening as outlined in Equation 14 where A is Table 2. Approximate Pressure Drops fob Lattice Retubn Intakes....... . Inches Water Gage--Standard Air PERCENT; Frsb Area 400 50 .............60------------ .. 70 , 80 0.06 0.04 0.03 0.02 sqo - 0.09 _.0.06 0.05 0.Q3 FraFacb Velocity, 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 eoo 0.28 0.20 0.15 0.11 1000 0.35 0.24 0.18 0.14 the exhaust wall area in square feet. Recommended return intake face velocities ..sure given in Table 1. : 2. Permissible Pressure Drop. The permissible pressure drop will depend on thechoice of the designer. Table 2 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 gfille area: The major difference betWeen the supply outlets and return intakes is the frequent installation of the latterat ear-level. -When so located, it iarecommended that the return intake velocity be not in excess of 75 percent of the maximum permissible outlet velocity. .- . .: . Outlet Location The control of the room air motion for the maintenance of comfort con ditions depends oh the proper selection of the supply outlets. The loca tion of-the Teturn or exhaust intakes does not critically affect air motion, un less room air velocities in the occupied zone adjacent to the intake exceed comfort lirriits. The locations of return or exhaust intakes are, however, important for obtaining the desired room temperature equalization. Ceiling locations for exhaust putlets are recommended for bars, kitchens, .lavatories, dining rooms, club rooms, etc., where warm air will rise to the ceding level. In heating installations, location of the return grilles in the Air Distribution -665 ceiling or high on the wall will result in stratification of the conditioned air, and a high percentage of the heated air will be drawn into the return duct before it has served its purpose. (Refer also to considerations outlined previously in section. Outlet Location and Selection in this chapter.) Some circular ceiling outlets combine the supply and return openings in a single unit. The return duct is in the center with the supply pattern on the outside. This method gives best results for cooling applications. The application for heating is more critical and requires consideration of ceiling height, amount of outside wall area, and number of air changes required. In some cases, stratification of warm air may cause short circuiting. Where the wall losses are a small part of the total, little difficulty is encountered with stratification. '. 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 Rear wall distramtion ' . . Ceding distribution Fig. 8. Aib Distribution Methods fob Theaters, Chubches, and Auditoriums . 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 imbalanced 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. 8 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 bal cony, where, ceiling heights are low and where direct impingement of air is sometimes a hazard. -. . Wall or ejector distribution is particularly applicable for relatively long and narrow theaters. It is essential with this type of distribution that there be no interference with the movement of air throughout its entire path from the high velocity nozzles to the front of the theater. The ceiling should be smooth, without projecting beams or obstructing ornamentation. For large 666 CHAPTER 30 1952 Guide Fio. 9. Distribution Methods for Small Rooms A. Satisfactopr for cooling. Unsatisfactory for heating in severe climates where the outside tem perature is consistently below 40 F, and single glass and uninsulated walls are prevalent.- -' B. 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. - . ` D. Satisfactory for both cooling and heating. The air should be discharged slightly away from the wall, and-for low velocities, should be fanned out parallel to the wall. . - : . . _ . ; 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 system during the winter heating period,, the returns should: preferably be located at the floor level and heir the front of the theater to prevent cold spots which may result from exposed wall convection or infiltration from exits. ; ..... , " For mvUi-rocm buildings diagrams shown in'Fig. 9 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 zllz J `r A [j : t t t r t' 1--1 v W V' wV ' <P , Fiq; 10. 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 Walls. Moderate room air motion, outlet blows should not impinge giving rise 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 size to allow for blocking when not located in perfect squares; - ' - '' Air Distribution 667 is illustrated in Fig. 10. Marine applicationsof air distribution systems are . given in Chapter 47. REFERENCES. Control of Air Streams in Large Spaces, by G. L. Tuve and G. B. Priester (A.S.H.V.E.. Transactions, Vol. 50, 1944, p. 153). .. . 'Air Conditioning Principles, by C, O. Mackey (International, Textbook ..Com pany, Scranton, Pa:, 1941, p. 187). .. ' ' . ' ... ' ' * Throw of Air from Slots and Jets, by R. D. Madison and W. R. Elliot (A.S.H.V.EJournal Section, Heating, Piping and Air Conditioning, Noy,. 1946, p! 108).. . 4Modem Air Conditioning, Heating and Ventilating,, by, W.. H. Carrier, R.- E: Cherne, and W. A. Grant (Pitman Publishing Corp., New York, N.',Y., 1940).... . s A.S.H.V.E. Research Report No. 1155--The Performance-of Stack Heads, by. D. W. Nelson, Di H. Krans and A. F. Tuthill (A.S.H.V.E. Transactions; Vol. 46; ltun ,, onu-i 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 ; : ; ./ " Jets . Calculation, of Turbulent Expansion Processes, by W. Tollmien (NACA .Tech. Memo. No. 1085, September, 1945). .. . Investigations of the Turbulent Mixing Regions Formed- by Jets, by A. M. Kuethe (Joumalof Applied Mechanics, Vol. 2, p. 87,1935). ... . ,, Air Flow at Discharge of. Fan-Pipe Lines in Mines, Part II. by G. E. McElroy (U. S. Bureau of Mines Report of Investigations No. 3730, November, 1943).. vV: .Investigation of Flow in an Axially Symmetrically. Heated Jet of Air, by S.iCorrsin (NACA-ACR No. 3123--declassified--December,-1943). ; .! . j Isothermal and Nonisothermal Air Jet Investigations, by V. Cleeves and L. M. K. Boelter (Chem. Eng. Progress, Vol. 43, No. 3, Trans. Section, March 1947, p. 123). Diffusion of Submerged Jets, by M. L. Albertson, Y.-B. Dai, R. A. Jensen and Hunter Rouse (Proceedings ASCE, December 1948, p. 1571).. = ' . ... f...s Air Distribution . '' . . . . . . .. ... . A.S.H.V.E. Research in Air Distribution and Air Duct Friction,' 'by C. Tasker (A.S.H.V.E. Journal Section, Hailing, Piping and Air Conditioning, April 1948,p. 125). Turbulence--A Fundamental Frontier in Air Distribution, by H. B. Nottage (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, April 1949, p. 115). Air Distribution and Draft, by J. Rydberg and P. Norback (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, January 1949, p. 167). Downward Projection of Heated Air, by Linn Helander and C. V. Jakowatz (A.S.H.VJE. Journal Section, Heating, Piping and Air Conditioning, March 1948, p. 129). Outlet Performance The Rationale of Air Distribution and Grille Performance, by C. O. Mackey (Refrigerating Engineering, June 1938, p. 417). 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. 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). A.S.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). Slots and Perforated Panels Air Discharge from Narrow Slots, by F. F. Stevenson (Heating, Piping and Air 668 CHAPTER 30 1952 Guide Conditioning, May, 1941, p. 308, and June, 1941, p. 368.. Discussion by J: R. Fellows and D. W. Nelson, loc. cit., September 1941, p. 558 and 559). .. The Discharge of Air From a Long Slot, by A. Koestel and G. L. Tuve (A.S.H.V.E". Journal Section, Heating, Piping and Air Conditioning,..January 1948, p.. 153). Air Streams from Perforated Panels, by A. Koestel, Philip Hermann.and G. L. Tuve (A.S.H.V.E. Journal Section, Healing, Piping and Air Conditioning, July 1949, p. 107). ...'-- .... Instrumentation . . . A.S.H.V.E. Research Reports No. 857, 911 and 966--Measurement of the Flow. of Air Through Registers and-Grilles, by L. E. Davies (A.S.H.V.E. Transactions, Vol. 36, 1930, p. 201; Vol. 37, 1939, p. 619 and Vol. 39, 1933, p. 373). Measuring Air Distribution and Grille Performance in Air Conditioning, by G. L. Tuve {Heating, Piping and Air Conditioning, November 1937, p. 700). 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.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 and Grilles, by G, L, Tuve and D. Kv Wright, Jr. (A.S.H.V.E. Transactions, Vol. 46, 1940, p: 313): ....................... . A.S.H.V.E. Research Report No. 1165--Development of. Instruments for the Study of Air Distribution in Rooms, by A- P- Hratz, A. E. Hershey and R. B. Eng- dahl (A.S.H.V.E. Transactions,' Vol. 46, 1940, p. 351). . Miscellaneous _. 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. 959--Indices of Air Change and Air Distri bution-, by-F. C. Heighten and J. L: Blackshaw (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 261). A.SN.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), . . . . . .; Vertical Air Distribution in Tall Buildings, by-Wm. Sturm (Heating, Piping and Air CondiHoning; June 1947, p. 69 and September 1947, p. 93). Balancing Air Delivery of- a System of Manifold Air Diffusers,by G. S, Dauphinee and P. Argentieri (A.S.H.V.E. Journal Section, Heating, Piping and Air. Con ditioning, April 1949, p. 105). CHAPTER 31 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 Construc tion Details, Heat Losses from Ducts, Maintenance ! /\IR ducts for the transmission of the air in forced air heating,'ventilat- mg, 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 6f . the flow of. fluids will be found in Chapter 4, Fluid Flow. - !, PRESSURE LOSSES ; I: ; ' Air .ducts, impose resistances to air flow which must be; overcome by pressure differences resulting from the expenditure of energy in mamtaining - 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 causeronly 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 fpr 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 outlbt to balance the system, ; . , : ` . -j 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 of air flow, and may be caused by changes in size and.shape of the cross section of the duct, by bends (elbow's), and by obstructions to flow offered by dampers. ;. , FRICTION LOSSES Pressure drop in a straight duct is caused by surface friction, and this friction loss is most- readily calculated by means of the Air Friction Charts, . 669 670 CHAPTER 31 1952 Guide Air Duct Design 671 CU FT OF AIR PER MINUTE CU FT OF AIR PER MINUTE' For Volumes of 10 to 2000 cfm (Based on Standard Air of 0.075 lb per eu ft density flowing through average, dean, round, galvanised metal ducts having approximately 40 joints per 100 ft.) No safety factor included. Caution: Bo not extrapolate below chart. . ` Vor Volumes of 1000 to 100,000 cfm (Based on Standard Air of 0.075 lb per cu ft density flowing through average, clean, round, galvanised 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.E. 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): . ........ 1 672 CHAPTER 31 1952 Guide y _ yy h, fit. 0 2} (1) where i hi = head loss due to friction, in feet of fluid flowing, f !;= length of conduit, feet?' ` . ; /) = inside diameter of conduit, feet. ' . o = .mean fluid velocity, feet per second. ' . 1 g = acceleration due to gravity, 32.17/feet per (second) (second). ' f = a non-dimensional friction coefficient, which tor ventilation work depends ; upon Reynolds Number ^and the relative roughness of the conduit. Appro- \ j 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 air* with a density of 0.075 ;lb per cu ft, flowing throujgh 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 jvidely 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 jas the density without'serious error, and therefore , where ' ; '. ' l ho : friction loss under actual .operating conditions, any consistent units. ;: h. = friction loss under standard conditions, any consistent units. Pa = 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 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 ana-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 673 Fiq. 3. Correction Factors fob Pipe Roughness ; .To correct for pipe roughness n^ultipiy friction loss .obtained from Figs-1 and 2 by correction factor ob tained from'Fig. 3. - Example 8: If the duct in Example 1 is very rough, instead of galvanized, with 40 joints per 100 ft, find the total friction. ...... _v- Solution: On Fig. 3 find (by interpolation between 12 in. and 40 in. pipe) the 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'rough duct is therefore 2 X 0.38 = 0.76 in. .. CIRCULAR EQUIVALENTS OF RECTANGULAR DUCTS * An air handling system is visually sized first for round ducts. Then, if f rectangular'ducts are desired, their sizes "are selected to provide air carry ing capacities equivalent to those of the round ducts originally selected. . . A recent comprehensive study at the A.S.H.V.E. Research Laboratory proved: that for; most practical purposes rectangular ducts of aspect ratios not exceeding 8:1 will have1 the same .static friction pressure loss for equal .. ,. r Table 1. Values, of Roughness t for Different Pipes* Pipe Degree or Roughness - - c ' ` Roughness in Feet . DrawnTubing. . ............................................ Very smooth New Steel or Wroiight-Iron Pipe........................... Medium smooth Galvanized Iron . . ....................................................!. Average Average Concrete .....!....................................... .. Medium rough . Average Riveted Steel. . . . ............... ........................ Very rough * Used in computing values for Fig. 3. 0.0000015 : 0.00015 0.0005 . . 0:003 0.01 ' v.-FfT- 674 CHAPTER 31 1952 Guide Air Duct Design 675 -lengths and mean'velocities of flow as a circular duct of the same hydraulic diameter. When duct sizes are expressed in tertns of hydraulic diameter, and when equations for friction loss in round and rectangular ducts are equated for equal capacity and equal length, an equation giving the circu lar equivalent of a rectangular duct is Obtained6 (Equation 3). where (o6)- d,, = 1.30 = 1.30 (o + 0!6 (ab)5 (a + &), (3) a length of one side of rectangular duct, inches. (Other side is 6.) 6 = length of one side of rectangular duct, inches. (Other side is o.): , d0 = 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 ductiby 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 of Rectangular Ducts for .Equal,Friction ' . - and Capacity ' -- , Dimensions in'Inches. . - : Side RECTAN 4J0 iS fi.0 ' M-. 6JO 6-5 7jD 7.5 8i> 8,5' W) . 9,5 - 10.0 GULAR PUCT 3:0 3.5 4.0 4.5 5.0 5.5 3.8 4.1 4.4 4:e 4.9 5.1 4.0 4.2' 4.4 4.3 4.6 4.8 4.6 4.9 5.1 4.9' 5.2 5.4 5.2 5.5 5.7 5.4 5.7 6.0 4.6 5.0 5.3 5.6 6.0 6.3 4.8 5.2 6.5 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 6.5 6:0 6.4 6.9 7.3 7.6 5;6: >6.1 6.6 7.0 7.4 7.8 5:7 6.3 6.8 7.2 7.6 8.0 Side Rectan ion 10.5 1L0 11.5 12J) 12J 13JO 13.5 14.0 14.5 ISjO 15.5 16.0 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 7.0 7.6 8.3 8.9 9.4 9.8 Table 2. Circular Equivalents of Rectangular Ducts for Equal Friction and Capacity (Continued) ' Dimensions in Inches - Side _ Reo- _ TAN 6 7 8 9 10 11 12 13 14 15 16 17 j 18 18 ' GULAB Duct 6 6.6 7 7.1 7.7 8 7.5 8.2 8.8 9 8.0 8.6 9.3 9.9 10 8.4 9.1 9.8 10.4 10.9 11 8.8 9.5 10.2 10.8 11.4 12.0 12 9.1 9.9 10.7 11.3 11.9 12.5 13.1 13 9.5 10.3 11.1 11.8 12.4 13.0 13.6 14.2 14 9.8 10.7 11.5 12.2 12.9 13.5 14.2 14.7 15.3 15 10.1 11.0 11.8 12.6 13.3 14.0 14.6 15.3 15.8 16.4 I 16 10.4 11.4 12.2 13.0 13.7 14.4 15.1 15.7 16.3 16.9 17.5 10.7 11.7 12:5 13.4 14.1 14.9 15.5 16.1 16.8 17.4 18.0 18.6 18 11.0 11.9 12.9 13.7 14.5 15i3 16.0 16.6 17.3 17.9 18.5 19.1 19.7 19 11.2 12.2 13.2 14.1 14.9 15.6 16.4 17.1 17.8 18:4 19.0 19.6 20.2 20.8 20 11.5 12.5 13.5 14.4 15.2 15.9 16.8 17.5 18.2 18.8 19.5 20:1 20.7 21.3 22 12.0 13.1 14.1 15.0 15.9 16.7 17.6 18.3 19.1 19.7 20.4 21.0 21.7 22.3 24 12.4 13.6 14.6 15.6 16.6 17.5 18.3 19.1 19.8 20.6 21.3 21.9 22.6 23.2 26 12.8 14.1 15.2 16.2 17.2 18.1 19.0 19.8 20.6 21.4 22.1 22.8 23.5 24.1 28 13.2 14.5 15.6 16.7 17.7 18.7 19.6 20.5 21.3 22.1 22.9 23.6 24.4 25.0 30 13.6 14.9 16.1 17.2 18,3 19.3 20,2 21.1 22.0 22.9 23.7 24.4 25,2 25.9 32 34 36 38 . 40 42 . - 44 46 ' "48 l 50 52 . 54 14.0 14.4 14.7 15.0 15.3 15.7 16.1 16.4 16.5 17.0 17.4 17.8 17.7 18.2 18.6 19.0 18.8 19.3 19.8 20.3 19.8 20:4 20.9 21.4 20.8 21.4 21.9 22.5 21.8 22.7 22.4 23.3 23.0 23.9 23,5- 24.5 23.6 24.2 24.8 26.4 24.4 25.1 25.8 26.4 25.2 25.9 26.6 27.3 26.0 26.7 26.7 27.5 27.4 28.3 28.1 29.0 15.3 15.6 15.9 16.2 16:8 17.1 17.5 17.8 18.2 18.5 18.9 19.2 19.4 19.8 20.2 20.6 20'7 21:1 21.5 21.9 21.9 22.3 22.7 23.2 23.6 23.4 23.9 24.3 24.0- 25.1 24.5 25:6 25.0- 26.1 25.5 26.7 26.0 26.6 27.2 27.7 27.0 27.6 28.2 28.7 27.9 28.5 29.1 29.7 28.8 29.7 29.4 30.4 30.0 31.0 30.6 31.6 16.5 16.8 17.0 17.3 18.1 18.4 18.7 19.0 19.6 19.9 20.2 20.5 20.9 21.3 21.6 22,0 22/3 22.7 23.1 23.4 23.6 24.0 24.4 24.8 24.8 25.2 25.6 26.1 26.0 27.2 26.4 27.6 26.8 28.1 27.3: 28.5 28.2 28.7 29.2 29.7 29.2 29.8 30.3 30.8 30.2 30.8 31.4 31.9 31.2 32.2 31.8 32.8 32.4 33.4 32,9 33.9 56 . 17.6 19:3 20.9 22.4 23.8 25.2 26.5 27.7 28.9 30.1' 31.2 32.4 33.4 34.5 58 17.8 19.5 21.1 22.7 24.2 25.5 26.9 28.2 29.3 30:5 31.7 32.9 33.9 35.0 60 18.1 19.8 21:4 23.0 24.5 25.8 27.3 28.7 29:8 31.0 32.2 33.4 34.5 36.5 62 18.3 20.1 21.7 23.3 24.8 26.2 27.6 29.0 30:2 31:4 32.6 33.8 35.0 36.0 64 18.6 20.3 22.0 23.6 25.2 26.5 27.9 29.3r 30.6 31V8: 33.1 34.2 35.5 36.5 66 18.8 20.6 22.3 23.9 25.5 26.9 28.3 29.7 31.0 32.2. 33.5 34.7 35.9 87.0 68 19.0 20.8 22.5 24.2 25.8 27.3 28.7 30.1 31.4 32.6 33.9 35.1 36.3 37.5 . 70 19.2 21. 22.8 24.5 26.1 27.6 29.1 30.4 31.8 33.1 34.3 85.6 36.8 37.9 losses may be assumed to be caused by changes in area, actually occupied by the air flow, for convenience they are divided into two general classes: (1) those caused by changes in direction of the duct at bends and branches, and (2) those caused by changes in cross-sectional area of the duct at transi tions.' Dynamic losses vary substantially as the square of the mean velocity of T a b u s 2. C ie c u l a b E q u iv a l e n t s o f R e c t a n g u la r D ucts fo r E q u a l F r ic t io n a n d C a p . 676 CHAPTER 31 1952 Guide Dim ension) in Inches ' ipr 1 'ggSS SSSS SS83 ,-.583S S.SSS SSSS SSSS SSSS SSSS sss J ; ' . : : : . .; 11 221 ' i : .. : _ : . - - <,0,0.0. =>o>s> SSSS SSS : ; ; - : :-----S2 . :; . - : : :---:---------------- :-------- :-------- : = ' BS SSSS SSS : 3383 8"88 838 ssss ssss sss 8338 8888.383 s1 .., gg SSSS SSSS'- SSg ' . ; : : ~ ::. , . . " - gggK g'sss ssss-sss -.-.-.8 .8888 ;338 . . sn ssss gggg ..gsss. sss g - .. ;------------------------ 33 3t"33 S 888 -0333 883 .. . , : . ;SS SSSS SSS? CPS?:;S,SgE SSS ; : . ?- ' - . OJWVN - SSSS SSSS.-SSSfe.SSSC-sees ; --. %f: . ; S SSSS SSSS SSSS BBSS gfUrK CEE ! : 88 -> - .ss SSSB SSSS ,SSSS SSSS SSSS KKR . ,,,,,, -.= " .. - SES SSSS BSSS SSSS SSSS SSSS SKE . .. : s' : , ; ssse ssss ssbs ssss s.sss..sssb sss --------- ----------- ----- , . = , .. ,' . ,. .v S.: SSS? SSSS 0300J r-B39-w; -\: .. * . -* ; --ssss SSSB SSSS rtwooo no ssss -sssss -ir ""T SSSS, SSSS,-sss oeoot^ **Or-'* ssssi-ssss- sss 8 - . ' '593 5333 3SSSS SSSS SSSB SSS- SSSS SSS ----------- - . -('rr r=>s> g: 'SSSS.SSSS SSSS SSSS SEES ssss.ssss sss : ; .' ' & Ssss i3is ssss esss esss -sIs . 3 3333. 3333 00^0 . 3333 .333 ;S ; . gg ''SSSS "8333 5883 8333 SSSS 3385 S38S SB" -------------- ---' 3333 3333.3333 383.:3333 3333 333" . ;.g. " SSS SSSS;8853 3358-8888 8S3S SES3 SSSS sss , . .!=.; r!-. -'-S ; - f . S5SS : SSSS .SSS3 ESS" 5533 :3333 33SS- SSSS '3SS_ , . ~ ,,.oo. : =>-.=. 33 = 3 0303 -=- .'s |. g-ssss--.sss.sk.ssss ssss 8335.;.53ss 8888 ssss:;sss_ ' s ` 3-33 r33 3333 3333. 3333 ,333 SS SSSS. SSSS SSSS SSSS 3553-'3835 5333.3383 -33S_ ----- 3338 3333 3333 3333 3383 8333 3333 3333 38'f g . SSS BSSS SSSS SEES SSBS SSSS 3353 8335 5333 S3* 3333 3333 3333 3338 333 3333 3333 3333 3333 333" s ESSE SSSS SSSS SSSS ESSS SSSS SSSS SS53.S833 S5^_ . Ail Duct"Design 677 tKe air; and are therefore conveniently expressed as a fraction of.the:velocity head: -' ' ' ' - - :^ ` and for" standard air : .: . i. where h, = dynamic pressure loss, feet of fluid flowing. ,. , Fig. 4. Relation Between Velocity and Velocity Head for Standard Air f ^ = 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 number , of velocity heads lost at the conduit transition or bend. Yalues of the dynamic loss coefficient for various duct elements are sometimes tabulated,*-7- * 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 (Y = 4005can be conveniently used to find the total dynamic pressure loss for any duct element with known dynamic loss coeffxAent C. This coefficient is nearly independent of the air velocity and the roughness of the duct walls; therefore dynamic losses cannot theoretically be computed as friction losses. For duct components where intense eddying flow is not 678 CHAPTER 31 1952 .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. 5 gives the additional equivalent length of duct in terms of widths W for elbows in rectangular ducts; Fig. 6 gives the equivalent length in terms Air/ Duct/Design 679 the aspect ratio is ^H = 2g4 = 4.0; Fig. 5 gives (L/W)i =* 6, so Li = 6 X 6/12 = 3 addi tional equivalent-feet. . The total length of the straight runs from A to D is i = 1a-b + Ib-c + Ic-d = . 7 + 20 + 5 = 32:ft and the additional equivalent length due to the elbows isL -- In + Lt = 23. + 3 = 26 ft. Thus the equivalent length of the system from A to D is l + L = 32 + 28. = 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 byth'e 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 op Rectangular Cboss-Section of diameters D for round ducts. When these curves for additional equiva lent length are used, the straight lengths of duct between' elbowsshould be measured'to'tfie 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. .ExampUiS; - (Use of Fig. 5 for the calculation of elbow losses.) .. . 1 Given the portion of a duct system shown in Fig. 7, if is required to determine the 'pressure loss between points'A and D. 'Air at'standard conditionals-being supplied at'th'e rate of 2000'efm in a 6 by-24 in. galvanized duct of average construction. .El bows No; 1 and 2-have centerline radii of 18 and 9 in., respectively. .; , . Solution: For elbow No. 1 the radius ratio is = 24 = an<^ ^he aspect ratio ig =; ^ = 0.25. The additional equivalent length for elbow No. 1 in terms of W is obtained:from Fig. 5: (L/W), = 11.5. Thus L, = 11.5 X 24/12.= 23 additional equivalent feet!. Similarly for elbOw No. 2, the ratio radius is ^ = g = 1.5 and ' .. _ , RADIUS' RATIO, R/O . ., ., . Pro. Loss6. in 90-Deg Elbows op Round Cboss-SectiOn ' V aspect .ratio, H/W ~ 1/4, than if the bend of the same radius, ratio bad i been made in the plane of the narrow- dimension giving an aspect'ratio. H/W =.4. . . ! '.. . Data presently available for losses in compound bends/0- " where two,or more elbows are close together, do not warrant refinement of design calcu lations beyoiid 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. Data12 for losses at branch take-offs are at present quite meager. An A.S.H.V.E. cooperative investigation is underway for the purpose of obtain ing 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 680 CHAPTER 31 1952 Guide Fig. 7. Portion of Duct Ststem-^or Example 3 forms will prodiice a substantial saving in pressure loss. The addition of vanes or splitters, divides an elbow into parallel channels, each having more favorable radiud and,aspect ratios than the''original elbow. Values of addi tional equivalent length L, for elbows of square cross-section having various vane forms and1 combinations, may be found frqm Table 3 in which values of L/W are shown. . ; . -. ......... ; f ; ; : LOSSES DUE TO AREA CHANGES Area changes' in ducts,' generallyunavoidable, are necessitated frequently by the building construction or changes in the volume of air carried. Ex perimental investigations1416 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 Ibss 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. r: 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 of the contraction and reaches a minimum at the vena conlracia: 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, contracts to the'full area following the contraction. Enlargement in area may be considered as a special condition of general expansion following contraction.' Fig: 8 illustrates'(a) abrupt enlargement and (b) abrupt contraction. : . ' For a sudden symmetrical enlargement, ,a theoretical expression fpr the' loss is. . . ..' '*. 'A-.. ;v j;. Fig. 8. Air Flow at Abrupt Enlargement or Contraction of Air Stream Air Duct Design or for standard air; 681 where \ At/ \vm) V 4005 / (7) h* -- pressure loss due to sudden enlargement, feet of fluid flowing. H0 = pressure loss due to sudden enlargement, based on standard air, inches of water. .. Table 3. Pressure Loss in Vaned Elbows of Square Cross-section Expressed in Additional Equivalent Duct Length*. b ' . Additional Equivalent Length L = Duct Width W, in Feet, Multiplied by L/W Values Shown . MITER EL80W ELBOWS WITH VARIOUS RADIUS RATIOS R'yW 0 .2 .4. .6 A 1.0 R/W 0.5 R'/w 0 .2 .4 A .8 1.0 Uw'r; Rt n9 A L/W 20 % 70 34 28 33 54 60 Uw-1 % 60 20 19 24 30 60 X 0 .2 .3 .2 .3 RVw 0 .4 .5 .4 .5 RVw 0 0 O .6 j.7 % 70 22 22 18 20 R/W 0:5 - Rl,/W o .2 .3 .4 .5 .6 0 .4 .5 .6 .7 .6 % 60 .16 19 20 21 24 R/W 0.7 X 0 .4 .6 .8 1.0 1.2 14 15 % 24. 13 14 21 24 .c % 0 .7 .8 .9 1.0 1.2 D1 L/W 15 28 ' 70 % 10 8.0 6.0 7.4 7.2 7.4 ^ ` These values are based upon vane test data of Reference 13 which have been modified by the findins of Reference 9. . .' , 67anra: A = a large number of small arc vanes; B = a small number of large arc vanes; C.-- hollow vanes Having different outside and inside curvature; D = four vanes with radius of 0.4 W; E = single splitter with radius of 0.5 W; F = no vanes or spUtteia. w t>i = velocity in the inlet duct, feet per second. tit = velocity in the outlet duct, feet per second. V, = velocity of standard air in the inlet duct, feet per minute. Vt = velocity of standard air in the outlet duct, feet per minute. Ai = area of. the inlet duct, square feet. . . At = area of the outlet duct, square feet. - . . The loss for a sudden symmetrical contraction, he can similarly be ex pressed as *(lq)1 h, ,2g (8) 682 CHAPTER 31 1952 Guide where ' 'V : = pressure loss due to sudden contraction, feet of fluid flowing. v't = the velocity at the vena contracta, feet per second:; ; A't = the area of the vena contracta, square feet. "Introduction of the contraction coefficient a = ~ and the loss coefficient C = -- 1^ in Equation 8 gives (with At X v't = Ax X j): or for standard air: `'i (9) GO) where . Hc = pressure loss due to sudden contraction, inches of water. Vi = velocity of standard air in the inlet duct, in feet per minute. Values of a and C for sharp comers for increasing ratios of .A2/A1 are given in the following table: ', At/Ai ` ,0.01 0.1 : 0.2 0.4 0.6 0.8 1.00 -a ' 0.6 0.61 0.62 0.65 0.7 0.77 . 1.00 c 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 .ff = 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 duct. Values for C\ are given in the following table: Total Included Angle, Degrees Ci S 0.20 7 0.15 10 0.16 SO 0.35 80 0.65 40 0.80 SO 0.92 60 1.0 Air Duct Design 683 Pressure losses for various duct transitions and area changes have been determined experimentally, although the available information is generally restricted to symmetrical area changes.- '1415 *>17 . PRESSURE CHANGES The fundamental energy equation for standard air flow in a horizontal duct pan be written18 ' ; HS + + 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. Or5)'In Equation 12, H is a measure of the potential energy and | 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 losses and eddy formation are possible.19 In order to keep losses in an expanding duct section to a minimum and to convert the velocity pressure efficiently into static pressure, the angle of divergence should be kept small.70 Theoretically, it might seem possible to 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 tion of the principle of static regain in duct design is, of course, impossible for various reasons71 such as: the necessity of using sections of uniform diameter because of cost, the need for using ducts of dimensions varying . m full inches, the changing of duct sizes mainly at branch connections, and 684 CHAPTER 31 W 1952 Guide r - *. ' 4he! ine'vitable^tess 'due ta'turtrtilence- The principle of static pressure regdin.'is; However,"of importance in.the economical design' of duct.systems. Fig. 9 shows the application of static pressure negaih 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 duct, the diameter of which is equal to., the; fan outlet....jTjhe total .pressure,which pmst.be provided by the fan is therefore the sum of the pressure that is necessary to .overcome the fric tion in the duet (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 Fig. 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 \-t/Decrease in TotalPressure I Y OuetoStafie Pressure Regain Velocity Pressure ofthe MrLeaving the Systemj . P%ssure - - v ''StaticPressure Re-. gainm 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 hi in an abruptly expanded section is the difference in the velocity pressures of the1 small and the large duct, minus the dynamic pressure loss (Equation 6): -; (13) or simplified Vt(Vi -- Vi) 9 where . hi = regain' in static pressure, feet of fluid, flowing. (14) Air Duct Design 685 Vi and vt = mean velocities in inlet and outlet duct sections, respectively, feet ' per second. ... '. The static, pressure regain in a gradually expanding transition, followed by an after section, may be expressed, as . , , _ Jh _ \jg 2g\ ~Clfa -- Pi),~| [ -H J (15) or Ar = -- Cxfa - t>t) 2g . (16) where ' Ci = .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 w sections in smooth circular ducts.15'1 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 18 (Gravity Warm Air! Systems) and Chapter 19 (Forced Warm Air Systems). The design of ducts in industrial exhaust systems is discussed in Chapter 45. 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 be 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. Losses in contractions are low, but, the in cluded angle .of convergence should not be larger than 60 deg. ' - ' "' -A 4. Special care should be taken to avoid restriction'of flow'in elbows; or . trans- 1 formation pieces. . " ' : ' . ' ' ' 5. Where the greatest air carrying capacity per square foot of sheet metal is de sired, rectangular ducts should be made as nearly square as possible. Aspect ratios greater than 10 to 1 should be avoided. , ; .. 6. Ducts 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 general procedure for design is outlined as follows: .- . 1. Study the plan of the building and draw in roughly the most convenient system of ducts, taking cognizance of the building construction, avoiding, all obstructions in steel work and equipment, and at the same time'maintaining a simple design. 2. Arrange the positions of duct outlets to insure the proper distribution of air. 3. Divide the building into zones and proportion the volume of air necessary for each zone. . * .... ; . . 4- Determine the size of each outlet, based on the volume as obtained in the pre ceding paragraph; for the proper outlet velocity and throw. In case of some ceiling diffusers, determine Bize of outlet for proper throat velocity, and radius of diffusion. 686 CHAPTER 31 1952 Guide - 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, fpm ' Maximum Velocities, fpm Designation ` . Outside Air Intakes* Filters* ., Heating Coils* Air Washers Suction Connections Fan Outlets Main Ducts . Branch Ducts Branch Risers Residences Schools, Theaters, Public . Buildings Industrial Buildings Residences Schools, Theaters, Public Buildings * Industrial Buildings 500 500 250 300 450 500 500 .. 800 900 350 300 350. 600 500 ` 600 1200 350 700 500 500 500 . 500 500 500 700 800 1000 900 ' 1000 1400 1000-1600 1300-2000 1600-2400 1700 1500-2200 1700-2800 700-900 1000-1300 1200-1800 800-1200 1100-1600 1300-2200 . 600 600-900 800-1000 700-1000 800-1300 1000-1800 500 600-700 800 ' 650-800 800-1200 1000-1600 * These velocities are for total face area, not the net free area; other velocities in table are for net free area. portance of air velocities, elbow design, location of dampers, fan connec tions, grille and register approach connections, and similar details. For.industrial 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 an 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 is desirable to mount the outlet flush with the side of the duct, in which case Air Duct Design 687 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 30 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 tie 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 29 (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 cm 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. t 0. * air quantity in cubic feet per minute. Vm = air velocity in feet per minute. 1 . 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 loss found by adding the individual losses of the sections of the duct which has the highest resistance. This may be the duct with the longest nm, but 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- 688 CHAPTER 31 1952 Guide locities. Balancing is] obtained by use of dampers. The method is illus trated in Example 4- 1` . - iS. C4CQTI*OrMr ---A Oi --S.E..C..-.B..- O* --Sto-C 2O --SEC---0 O1 o*rr 20-ft -ft Flo. 10. Duct Layout fob Example 4 . . Example 4: (Velocity Reduction Method). A duct layout is shown in Fig. 10. V The fan delivers 8000 cfm. Four outlets deliver 2000 cfm 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.!). Results are tabulated in Table 5. . Section Table 5. Tabulation of Results (Example 4) . Ant Volume Velocity cfm fpm Area sq ft Area . Duct Size sq in.. ' in. . . Diam in. Frict per ' 100 rr in. HjO Frict Loss in. HsO A - . 8000 2200 3.64 524 26 x 20 . 24.8 0.25 0.10 B 6000 2000 3.00 432 22x20 22.9 ' 0.23 0.05 C 4000 1800 2.22 320. , 20 x 16 19.5 0.24 0.05 D 2000 1600 1.25 180 .. 12..x. 16.- 15.L .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 auto 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 auto 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 5: (Equal Friction Method). A duct layout is shown in Fig. 11. The fan delivers 2500 cfm. Outlets No.-T and 2 deliver 750 cfm each and outlet No. 3 de livers 1000 cfm'. Trunk velocity is assumed as 1500 fpm; the area will be 1.67 sq ft (240 sq in.); and the size will be 20 x 12 in. Determine sizes of ducts for sections B, Cy D and E and find the total pressure loss. . .. Solution: The equivalent round diameter of a 20 x 12 in;. rectangular duct is 16.8 in-. (from.Table 2).. Referring to Friction Chart, Fig. 2, a volume of 2500 cfm through Air. Duct Design 689 2-0 t 4 SECTION-A 20-rr SEC-0 * SEC-C d SEC-E IO-FT ^ 15-FT " sec-0 O-FT > S-FT--o. tS-FT. 3-6 Fig. 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 of Results (Example 5) Section Air Friction -Volume PER .100 FT. rfm in. Diam. in. Veloc ity fpm Rectan gular Duct . in. Friction PER 100 PT. in. Diam. in. Veloc ity fpm Rectan gular .Duct in. A' B C D E. 2500 750 1750 750 1000 0.2 16.8- 1620 20 x 12 0.2 : 17 1600 20 x 12 0.2 10.7 1190 10 x 9 0.286 10 1350 10 x 8 0.2 14.8 1400 15 x 12 0.2 14.5 1450 15 x 12 0.2 10.7 1190 10 x 9 0.4 9.8 1350 10 x 8 0.2 12 1300 10 x 12 0.2 12 1300 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 + C + E).. 0.12 (Du ct length = 20 ft + 10 ft +, 15 ft 4- 15 ft) Elbow loss................................ 0.02Loss through outlet.............. 0.12 . '. . Total pressure loss in . duct..................................... = 0.26 in.. . ' 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 lo88,_but also against the losses in all air conditioning apparatus such as washers or spray chambers, heating or cooling coils and filters. The static head required of theian 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 ldsses 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,, AH2, aHz to be the total pressure loss through ducts (1), (2) and (3); r, rb, rc, rd, re the friction losses in the straight sections of the system; rb., rde, r,, the elbow losses, and r,, r2, r, the loss through the outlets. Then, ' AHi = ri 4- rb 4- 2rbe 4- r, ' AHi = r,,~ 4- rc 4- rd 4- rd, 4- r2 AH, = r. + r,, + r, + r,, + r. If - . AH. - AH, = AH, -- AH . .. . * . n> + 2rbe = AH -- r. -- r. : .' ' ' rs + rd, = AH - r. -- r. -- r. 690 CHAPTER 31 1952 Guide or, using the values from Example 6: . n> + 2n>. = 0.26 - 0.04 - 0.12 = 0.10 in. . rd + rde = 0.28 - 0.04 - 0.02 - 0.12 = 0i08 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) 0.15 0.10 +2X 0.10 = 0.286 in. - 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 with a 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+20X^ + 15X^ + 0.12=0.26 . 0.06+ 10 X ^+ 10 X^j + 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 Hr = theoretical head recovered (static regain), inches of water. Vi = initial velocity of standard air, feet per minute. Vt = velocity,of standard air after reduction, feet per minute. . ' . 1 ' ' Under ideal conditions, 0.7 to 0.8 of the velocity head is actually re covered, but for practical design an average recovery of 0.5 is assumed. The actual velocity head recovered Hr, then becomes ... . "-"[(iss) (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 2000 Air Duct Design _ _ 691* ' <> 2 WIZ O 01 O (o0 t~o coc Z ZD . 5 Cb 2 iiii P fc <o->.-^o2>i. * 0H< U3 Ph Q HO .S* <0 < C<Q ^-S25? . 2^ OI o e O S 10 H U. 2;Z 2 001 rIoz--- ae asI SoJ 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 the 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 692 CHAPTER 31 1952 Guide Air Duct Design 693 outlet run). An outlet run is typified by Sections G-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 in Fig'. 14. The fan delivers 8000 cfm. Outlets 1, 2, 3 and 4 deliver 1500 cfm each, and outlets 5 and 6, 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 and 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 Solution: ,. . 1. Size Section F by the equal friction method so that ithas 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. X -y^r- = 0.03 in. water. . 3. Using Static Regain Chart, Fig/13, size Section B for. a net pressure loss equal to 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 sit the velocity in Section A (1500 fpm) at left margin. Proceed horizontally to 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 line, and1 from this.intersection proceed horizontally to the Air Velocity Base Line. Proceed 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). -- " 6000 , Since Section B carries 6000, cfm, the area required will be-y^^ 4 sqft, and the size of duct will be 36 x 16 in. 4. Using Static Regain Charts (Figs. 12 and 13) determine size of Sections C, D, E 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 from 1040 fpm.velocity; which is the.velocity in Section D. : . ' Duct sizes determined by-the given procedure are listed in Table 7on next page. 694 CHAPTER 31 ; 1952 Guide Section Table 7. Tabulation op Results (Example 6) An Volume efm Equiva lent Length ft Velocity fpm Rectangular Duct ' in. Diam. in. Friction TfPeb 100 in. HiO- NetPbxs* ffUBB LOSS in. H]0 A B C D -E 8000 6000 4500 3000 1500 40 1500 - 48 x 16 25 1500 36 x 16 15 13(H) 31 x 16 26* 1040 26 x 16 15 860 16 x 16 29.2 -- -- -- --` 0.13 . ---- -- -- - _ ---- .05 .03 0 0 0 F 2000 22.5 1200 G 1000 15 900 15 x 16 10 x 16 17. 0.13 .03 ---- 0 * Includes additional equivalent length of elbow between outlets 2 and 3, which is assumed as 3.5 W, ox II ft equivalent length of duct. (Based on 3000 cfm at estimated velocity of llOOfpm). ' 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 = 0.05 - Loss in Section F (or B) Outlet Loss Total Pressure Loss = 0.03 = 0.12 =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 swedged 1.5 in. from each end and assembled with the larger end of the adjoining section butting against the swedge. The sections are held in place by rivets, sheet metal screws, or by soldering, - Rectangular ducts are generally constructed by breaking the corners 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 thp 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-vulcanizing Air Duct Design 695 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, arid.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 S SBp. Drive sEp End . sEp Double $cam Pittsburgh seam Bar sfip bar sfip Rocket dip Angle connection Good . Fair Heater, filter, and washer connecfiua - . fay noted poor. When obstructions cannot be avoided, the duct area should never be decreased more than 10 percent, and then a streamlined collar should be used. Larger obstructions require an increase in the duct size in'order to maintain as nearly uniform velocity as possible. Branch take offs should always be arranged to cut or slice into the air stream in order to reduce as far as possible the losses in velocity head. - 1 Wherever ducts pass through fire walls or connect two fire areas of a building, automatic fire dampers should be provided. For design of such 696 CHAPTER 31 1952, Guide -dampers and other fire protective details, see Pamphlet No. 90 of the Nationai Board of Fire Underwriters.0 The recommended gages for steel (or iron) and aluminum sheet metal rectangular ducts are given in Table 8. Steel or iron sheets are specified according to the Manufacturers or U. S. 'Standard Gage System. Alu minum sheets are specified according to the American or Brown & Sharpe Gage System. Weights of black and galvanized steel and iron sheets per square foot of surface, for.various gages are given in Table 9. Similar data for 2S aluminum sheets will be found in Table 10. Weights of standard Table 8. Recommended Sheet Metal Gages fob Rectangular Duct Construction* .' ' Alu minum B.&S. Gage Steel U.B. Std. Gage Maximum Side, Inches Type of . TBANSVERBS JOINT CONNECTIONS ' Bracing 24 26 Up to 12 S, Drive, Pocket or Bar Slips, on None 7 ft 10 in. centers . 13 to 24 S, Drive, Pocket or Bar Slips, on None- 7 ft 10 in. centers ; 22 24 25 to 30 S; Drive, 1 in. Pocket or 1 in. Bar lxl x j in. angles Slips, on 7 ft 10 in. centers0 4 ft from joint 31 to 40 Drive, 1 in. Pocket or 1 in. Bar 1 x 1 x i in. angles Slips, on 7 ft 10 in. centers0 4 ft from joint 20 22 4i to 60 1J in. Angle Connections, or 1} in. 1J x 1J x ,, in. angles Pocket or 1$ in. Bar Slips with 4 ft from joint If in. x J in. bar reinforcing on 7 ft 10 in. centers" . 18 20 61 to 90 1$ in. Angle Connections, or H 14 x-14 x 4 in. diagonal in. Pocket or 14 in. Bar Slips angles, or 14 x 14 x 4 3 ft 9 in. maximum centers with in. angles If x | in. bar reinforcing 2 ft from joint 16 18 91 and up 2 in. Angle Connections or If in. 14 x 14 x 4 in. diagonal Pocket or 1$ in. Bar Slips 3 ft angles, or 14 x 14 x 4 9 in. maximum centers with If x in. angles. f in. bar reinforcing4 " 2 ft from joint terns. Where special rigidity or stillness is required, aucis snouia ue wusuuuwu m tucm vnu * .w. 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, b Other joint connections of equivalent mechanical strength and air tightness may be used. * Duct sections of 3 ft 9 in. may be used with bracing angles omitted; instead of 7 ft 10 in. lengths with joints indicated. . 4 Ducts 91 in. and larger require special held .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 M hard temper , are readily workable, and can be used for practically all auct work. , The 2S type (commercially pure aluminum) is suitable for all, except very large ducts. For large ducts, where more strength is desired, the 3S alloy with % 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 op Black and Galvanized Sheets 697 u.s. Std. Gags Black Sheets Approximate Tbickn ess, In. Weight Per Square Foot Galvanized Sheets* Thickness, In. Weight'Per Square Foot Steel Iron Ounces Pounds Steel * Iron Ounces Pounds 30 28 26 24 22 20 18 16 14 12 11 10 0.0123 . 0.0153 0.0184 0.0245 0.0308 0.0368 0.0490 0.0613 0.0766 0.1072 0.1225 0.1379 .. 0.0125 . 0.0156 0.0188 0.0250 0.0313 0.0375 0.0500 0.0625 0.0781 0.1094 0.1250 0.1406 .8 10 12 16 20 24 32 40 50 70 80 90 ,0.500 0.625 0.750 1.000 1.250 1.500 2.000 2.500 3.125 4.375 5.000 5.625 0.0163 0.0193 0.0224 0.0285 - 0.0346 0.0408 0.0530 0.0653 0.0806 0.1112 0.1265 0.1419 0.0165 0.0196 0.0228 0.0290 0.0353 . 0.0415 0.0540 0.0665 0.0821 : 0.1134 0.1290 0.1446. 10.5 0.656 12.5 0.781 14.5 0906 18.6 ' 1.156 22.5 -1.406 26.5 l.ARA 34:5 42.5 52.5 : 2.656 -.9 OKI 72.5 4.531 82.5 ' 6.166 92.5, A.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. Repeated 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 compensate1 for the heating effect of the duct surface. . - The thermal transmittance U for ducts can be found as follows: ' ; ' ! For uninsulated metal duct, U = ' ' 7,+To '- (20) J 10. 2S 0.098Table Weights and Thicknesses op. Aluminum (Density lb/cu in.) B. & S. Gage 28 26 24 22 20 .18 16 14 . Thickness, Inches Decimal 0.012 0.016 0.020 0.025 0.032 0.040 0.051 0.064 . Nearest Fraction 1/64 1/64 1/64 1/32 1/32 .. . 3/64 3/64 ' 1/16 Weight peb Square Foot Ounces 2.7 3.6 4.5 5.4 7.2 9.0 11.5 14.4 . .Pounds 0:169 " 0.226 0.282 : : 0.353 0.452 ' , 0.563 0.720 0.903 : 698 CHAPTER 31 1952 Guide ... . For uninsulated non-metallic ducts, l ' V= l+*-+ i /i fc Jo (21) where T7 == overall coefficient of heat transfer, Btu per (hour) (square foot) (Fahren- . .; heitidegree).. ; ." /i = surface conductance (inside) Btu per (hour) (square foot) (Fahrenheit - degree). Jo = surface conductance (outside) Btu per (hour) (square foot) (Fahrenheit degree). . x = thickness, inches. k = unit conductivity of material, Btu per (hour) (square foot) (Fahrenheit ' degree per inch thickness). Table 11; Weights and Thicknesses of Standard. Copper. Sheets*. Rolled to.Weight . ... . Weight per Square Foot Pounds 1120 0.625 0.750 14 0.875 16 1.000 18 1.125 20 1.250 24 1.500 28 1.750 32 2.000 36 2.250 40 2.500. 44 2.750 48 3.000 56 3.500 64 4.000 ' Thickness, Inches ' Decimal Equivalent ~ 0.0135 0.0162 0.0189 0.0216 0.0243 0.0270 0:0324 0.0378 0.0432 0.0486 0.0540 0.0594 : 0.0648 0.0756 0.0864 . - ' Nearest Fraction Uut. 46 '6 ' 44 6 4 6 V44 A% Nearest Gage NoJ B.&S. 27 26 25 21 20 19 17 16 15 15 14 13 11 Stabs 29 27 26 24 23 22 21 20 19 18 17 : 1176; 15 14 U.aSro, 29 28 28 25 24 23 22 20 19 18 1 17 17 16 14 13 Variations from these weights most be Expected In practice*-. '' oC - ' < Where x is small and k is large, however,- the factor r 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: 0.32!) /i - D,.,s (22) where . v = velocity of air in duct, feet per second. D = inside diameter of duct, feet. Film conductance /<> 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 Diict-Design -. The heat loss from a given length of duct can be expressed by: 699 where ' ' . Qw = heat loss through duet walls, Btu per hour. P = perimeter of duct, feet. '' l = length of duct, feet. . t, = temperature of air entering, duct, Fahrenheit degrees. h = temperature of air leaving duct, :Fahrenheit. degrees. .; t3 = temperature of air surrounding duct, Fahrenheit degrees. The heat given up by the air in the duct is: . ' : ' . where Q. = 0.24w(ii - l,) = UAAVmpAh ~ fe) ' :. (24) to = weight of air through duct,' pounds per hour. - A = cross-sectional area of duct, square feet. < - Vm = mean velocity of fluid,.feet per minute. , - pv = density of air at specified temperature at which, velocity Va, is measured pounds per cubic foot. .. , Equating (23) and (24): ...... . fi -f- tt -- 2f, - 28.8.4 VniPr :- j- ti tt " UPI - - Let y = 28.8A.FmPr for rectangular ducts, and'J.2Z)FmPv for round ducts UPl Ul and solve for h and fe: ti -- Uy + 1) - 21, (y - l) (25) ti ~ ti(y --.-1) +2<i (y.+ i) (26) For low velocities and long ducts of small, cross-section, a somewhat more accurate formula may be used as follows: -; : f, = ^ + <! (27) where '. - . UPL Z 14.4Ap,,Vm' e -- Naperian base of logarithms = 2.718. '' . In using Equations 25, 26, and 27, one of the duct air temperatures will be unknown and will be obtained by substitution of the , other known or assumed values. .' Heat loss coefficients for insulated ducts with various conductivities are given in Fig. 16. The conductivities of various materials, which are based on mean temperatures, ranging from about 70 to 90 F, will be found in Table 2 of Chapter 9. For cases where the mean temperature is other 700 CHAPTER 31 1952-Guide 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 neglected. Example 7: Determine tHe entering air temperature and heat loss for a-duct 24 X 36 in. cross-section and 70 ft in length, insulated with ) in. of a material having a 16. LossFig. Heat Coefficients fob Insulated Ducts* . * For round ducta less than 30 in. diameter, increase heat transmission values by the percentages shown Thickness op Insulation (laches) i 1. . H . 13% 5% % i% 2% 3%- . conductivity of 0.35 Btu at 86 F mean temperature, carrying air at a velocity of 1200 ;fpm, measured at 70 F, to deliver air at 120 F with air surrounding the duct at 40 F. ", Solution: Referring to Fig. 16, the overall heat transmission coefficient is found to be 0.49 Btu. From Table 1, Chapter 3 the density of air'at 70 F and 29.921 in. Hg Air- Duct' Design 701 is found to be 1/13.348 = 0.0749 lb per cu ft. Substituting these and the other given values in Equation 25, y and h will be as follows: . - 28.8 X 6 X 1200 X 0.0749 '. V = ------. -=0.4495.3X 10 X 70 tl = 120(45.3 + 1) - 80 = 123.7F 45.3 - 1 Substituting in Equation 23: Q, = 0.49 X 10 X 70 ^123 ?2+ 120) - 40J = 28,100 Btu per hr. For special considerations which apply to insulation of ducts in marine installations see Chapter 47.' . ' ' -. ... ... MAINTENANCE Ducts should be designed in such a manner as to enable easy mainte nance.*3 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.26-26 - LETTER SYMBOLS USED IN CHAPTER 31 a = coefficient of contraction, . . -= absolute roughness, feet. . -, Po = density of air under actual (operating) conditions, any consistent units. . .. . . p = density of air under standard conditions, any consistent units. pv = density .at which Fm is measured, pounds per cubic foot.. ,, , . A = cross-section area of duct, square feet. - . , .;.V . . :. . Ai. = area of inlet duct, square feet. .. At = area of outlet diict, square feet. '" .' " ' - ; . A't = area of vena contracts, square feet. . :, a = length of one side of rectangular duct, inches. (Other side is 6.) ' 6 = length of one side of rectangular duct, inches. (Other side;is a:) C and Ci -- dynamic loss coefficients, -dimensionless., a = regain constant, dimensionless. :. ... '. . ,. D = inside diameter of duct, feet. - .. . : ... <4= circular .equivalent of a rectangular duct for equal friction and capacity, inches. ................ .............` . - ' , - ,e = Napcrian base of lpgarithms = 2..718, . .' / = non-dimensional'friction coefficient. ' ,'i -' '"'J1 . ... /i =-8urface,conductance (inside) Btu per (hour) (square foot) (Fahien- heit degree). , . . .: /o -- surface conductance (outside) Btu per (hour) (square foot) (Fah- renheit-degree).. . . .... -,- ' g = acceleration due to gravity, 32.17 feet per (second) (second), ., ; . m =. duct dimension perpendicular to plane of bend, feet.; .'. H/W = aspect ratio, dimensionless. . F ... , Ho = pressure loss due to sudden contraction, based, on standard air, . . inches of water. . .. ... . . . ., II. -- pressure loss due to sudden enlargement, based on standard' air, inches of water. ''' " ....... E,, = pressure loss due to gradual enlargement, based on standard air, inches of water. ' ;. Ht = dynamic loss for standard air, inches of water. v .J .. Hi and H, = 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. . ... . . 702 CHAPTER 31 1952: Guide A0 = frietion loss under actual (operating) conditions, any consistent Units. .. : As = pressure loss due to sudden contraction, feet of fluid flowing! . h, = pressure loss due to sudden enlargement, feet of fluid flowing. hi = friction loss, feet of fluid flowing. --... hr = regain in static pressure, feet of fluid flowing. . h. = friction loss under standard conditions, any consistent units. hr = total dynamic pressure loss, feet of fluid flowing. ' k = conductivity, Btu per (hour) (sqft) (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. I = length of straight duct, feet. - P = perimeter of duct, feet. , Q = air quantity, cubic feet per minute. . ' ... . Qw -- heat loss through duct 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, ti = temperature of air entering duct, Fahrenheit degrees. ti = temperature of air leaving duct, Fahrenheit degrees, v ti = 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. . Vm .= mean velocity of air or fluid, feet per minute. ' - ' Vi = mean velocity of standard air in inlet duet section, feet per minute. V, = mean velocity of standard air in outlet duct section, feet per minute. v = mean fluid or air velocity, feet per second. ti = mean velocity in inlet duct section, feet per second. Vt = mean velocity in outlet duct section, feet per second. . W =* duct dimension in plane of bend, feet, to = 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). 8 Friction Factors for Pipe Flow, by L. F. Moody (A.SM.E. Transactions, Vol. 66, 1944, p. 671). ,. * 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, Heating, Piping and Air Conditioning, October, 1946). . * Friction Equivalents for Round, Square and Rectangular Ducts, by R. G. Hueb- seher (A.S.H.V.E. Journal Section, Healing, Piping and Air Conditioning, Decem ber, 1947). * Winter Air Conditioning, by S. Konzo (National Warm Air Heating and Air Con ditioning Association, 1939, p. 363). . I Modem Air Conditioning, Heating and Ventilating, by W. H. Carrier, R. E. Cheme and W. A: Grant, 1940, p. 234 (Pitman Publishing Corp.). * Heating, Ventilating and Air Conditioning, by L. A. Harding.and A. C. Willard, 1932, p; 673 (John Wiley and Sons). `A.S.H.V.E. Research Report--Energy Losses in 90-Degree Duct Elbows: A Survey and Analysis of Available Information, by D. W. Locklin (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, September 1950, p. 138). 10: Pressure Loss in Ducts with Compound Elbows, by J. R. Weske (National Ad visory Committee for Aeronautics, Advance Restricted Report W-39, February 1943). II Pressure Losses in Rectangular Elbows, by R. D. Madison and J. R. Parker (Heating, Piping and Air Conditioning, July, p. 365, August, p. 427, September, p. 483, 1936). 18 Fittings Losses for Extended-Plenum Forced Air Systems, by H. H. Korst, N. A. Buckley, S. Konzo, and R. W. Roose (A.S.H.V.E. Journal Section, Healing, Pip ing and Air Conditioning, February 1950, pp. 111-118. . Air Duct Design 703 A.S.H.V.E. Research Report No. 216--Effect of 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 (17. S. Bureau of Mines, Information Circular I.C. 6663, p. 4) . . _ - . . . 45 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). '. : '< * 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). ' . . ' -. - 18 Fluid Mechanics, by R. C. Binder, 1943, p. 152 (Prentice-Hall). 80 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). :. 81 Duct Sizing with Partial Static Regain, by R. H. Anderegg and' F. W. Hutchin son (Heating, Piping and Air Conditioning, August, 1946, p. 97). \ 88 Power Savings Through Static Pressure Regain in Air Ducts, by 'J. R. Fellows (Heating, Piping and Air Conditioning, April, 1939, p. 219). .' 88 Standards of the National Board of Fire Underwriters (N.B F.IJ. Pamphlet No. 90, p. 21). !. ?4 Design of Air Conditioning Systems for Low Maintenance, by M. G. Kershaw (Refrigerating Engineering, October, 1946, p. 315). 88 Clean Your Ducts, by. G. L. Candler (Heating, Piping and Air Conditioning, July, 1947, p. 83).. .' ' - :'V ; 88 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.). 1: Elementary Mechanics of Fluids', by Hunter Rouse, 1946. (John Wiley & Sons, Inc.). . The Flow of Liquids, by W. H. McAdams (Refrigerating Engineering, February, 1925, p. 279). .' : : ' > 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.MJ3. 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 of Civil 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 Frictional Resistance to the Flow of Air in Straight Ducts, by F. C. Houghten, J. B. Schmieler, J. A. Zalovcik, and N. Ivanovic (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 35). Analysis of Factors Affecting Duct Friction, by J. B. Schmieler, F. C. Houghten, and H. T. Olson (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 193). 704 CHAPTER 31 1952 Guide ..1 The Flow of Air In Ducts, by E. Kemler (Heating and Ventilating, May 1936, p- 38). .. ; Total, Static and Velocity Pressure, by A. A. Berestheff (Heating, Piping and. Air Conditioning, March 1932, p. 195). , . PRESSURE LOSS IN ELBOWS \ , v. Experimental Investigation of Velocity Distributions Downstream of Single Duct Bends, by John R. Weske (National Advisory Committee for Aeronautics Technical Note 1471, January, 1948). .. Investigations of the Flow in Curved Ducts at Large Reynolds Numbers, by John R. Weske (Journal of Applied Mechanics, December, 1948, pp. 314-348. Flow, of Fluids in Curved Passages, by J: Eustice (Engineering, Vol. 120, 1925, p. 604). New Data for the Design of Elbows in Duct Systems; by Loring Wirt (General Electric Review, Vol. 30, June 1927, pp. 286-296). ASHVE Research Report 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 Transr. actions, .April 1944, pp. 177-183). ... , . ...... ASHVE Research Report--Friction Equivalents, for Round, Square and Rec tangular Ducts, by R. G. HuebBcher (ASHVE Journal Section, Heating, Piping and Air Conditioning, Vol. 19, December 1947, pp. 127-135). , . . . . . Loss in 90-Degree Pipe Bends of Constant Circular Cross Section, by Albert Hofmann (Transactions of the Hydraulic Institute of the Munich Technical University Bulletin 3, 1929, ASME 1935, pp. 29-41). .. Pressure Losses in Rectangular Elbows, by R. D. Madison and J. R. Parker (ASME Transactions, AER58-2, April 1936, pp. 167-176). . ASHVE Research Report No. 1211--Pressure Loss Caused by Elbows in EightInch Round Ventilating Duct, by M. C. Stuart, C. F. Warner and W. C. Roberts (ASHVE Transactions, Vol. 48, 1942, pp. 336^350). : Friction of Air in Elbows, by A. I. Brown (Power Plant Engineering, August 15, 1932, p. 630). ... Loss of Pressure Due to Elbows in the Transmission of Air Through Pipes or Ducts, 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. 76-477, June 11, 1929, pp. 188-212). An Investigation of Pressure 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). DUCT DESIGN . A Rational Method of Duct Design, by L. G. Miller (ASHVE Transactions, Vol. 43,1937,p. 71). MISCELLANEOUS Performance Tests of Asbestos Insulating Air Ducts, by R. H. Heilman and R. A. McArthur (A.SlH.V.E. Transactions, Vol. 44, 1938, p. 197). ; Aluminum in Heating, Ventilating and Air Conditioning, Reynolds Metals Co., Louisville, Ky. CHAPTER 32 ' " ' FANS .... . .\ Types, Fan Performance, Fan Laws, Fan Performance Curves, System Characteristics, Fan Arrangements, Fan Control, Motive Power, Fan Selection, Fan Installation, Fan Applications . .,. , I N HEATING, ventilating and air conditioning practice, the devices used to produce air flow are variously known as fans, blowers, exhausters or propellers. .. The' A.S.M.E. Test Code1 limits fans to those inwhich'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 vj- .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. Tnbeaxial 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.2 , FAN PERFORMANCE Fan performance is a statement of volume, total pressures,, static pres sures, speed, power input, mechanical and static efficiency, at a stated density. These terms are defined by the National Association of Fan Manufacturers2 as follows: 1. Volume handled by a fan is the number of cubic feet of air per minute expressed at fan outlet conditions. 70S 706 CHAPTER 32 1952 Guide /^ . 2. Total pressure of a fan is the rise of pressure from fan inlet to fan outlet. 3. Velocity pressure of a fan is the pressure corresponding to the average velocity determination from the volume of air flow at the fan outlet area. 4. Static pressure of a fan is the total pressure diminished by the fan velocity pressure. .-- 5. Power output of a fan is expressed in horsepower and is based on fan volume and the fan total pressure. 6. Power input to a fan is expressed in horsepower and is measured horsepower deliyered to the fan shaft. . , ., . '7. Mechanical efficiency 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. Fan outlet area is the inside area of the fan outlet. 10. Fan inlet area is the inside area of the inlet collar. . '" .. While the total pressure truly represents the actual pressure developed by the fan, the static pressure may best represent the useful pressure for overcoming resistance. In many installations, since the outlet velocity of the fan is greater than the duct: velocity, some of the velocity pressure :may be utilized by conversion to static-pressure within the system. 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 only the static pressure as available to overcome the system resistance. Fig. 1. Names and Definitions op Types of Fans Propeller Fan ...... A propeller, fan consists of a propeller or disc wheel within a mounting ring or plate. . ' : Tubeaxial Fan . ' A tubeaxial fan consists of an axial flow wheel within a 'cylinder. '' . . - . Vaneaxlal 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 consists of a fan rotor or wheel within a scroll type of housing. . Fans. 707 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 0.0001573 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 LAWS5 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 (a) Q: (b) P: (c) Power: Varies as fan speed. Varies as square of fan speed. Varies as cube of fan speed. 2. 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. 708 CHAPTER 32 t -. 3. Variation in Fan Size: . .. , At Constant RPM--Constant Air Density Constant Fan Proportions--Fixed Point of Rating () Q: Varies as cube of wheel diameter. --.... () P: Varies as square of wheel diameter. .(c). Tip Speed: Varies as wheel diameter. . , (d) Power: Varies as fifth power of diameter. . 1952 Guide . : , .- . A.'Variation in Air Density: Constant Volume--Constant System Fixed Fan Size--Constant Fan Speed (a) Q: Constant. (6) P: i Varies as density. , (c) Power: Varies as density. . . . . . . . . .. . . . . ' 5. Variation in Air Density: . Constant Pressure--Constant System ' ' '' Fixed Fan Size--Variable Fan Speed .. -'(a) Q. Varies'inversely as squareroot of density: (b) P: Constant. ., . .(c) RPM: Varies inversely as square root of density: (d) Power: Varies inversely as square root of density. ' 1; ; ... ... .. : \ 6. Variation in Air Density: 1 ` Constant Weight of Air--Constant System Fixed Fan Size--Variable Fan Speed , , ,(a)Q: . Varies inversely as density; (6) P: , . '()' RPM: ' (d) Power: Varies inversely as density. Varies inversely as density. :. Varies inversely as square Of density.' ` ! '. .... ;. ; ' :: ' - ; ;: . .: ', Examples 1 to 4 illustrate the application of the preceding fan laws. Example 1: A certain fan delivers 12,000 cfm at a static pressure of 1 in. of water when operating at a speed of 400 rpm and requires an input of 4 hp. If in the same installation 15,000 cfm are desired, what will be the speed, static pressure, and power? 15,000 Speed 400 X ,, ~ = 500 rpm 12,000 /500V_ Static pressure = 1 K 1.56 in. \400/ " J/500Y ' Power = 4 X = 751 hp Example S: 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 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? 1 ' ' Static pressure , 0.0602 ,, ^. 1 X 0,,.0,,7-5 = 0.80 in. 0.0602 Power = 4 X = 3.20 hp Example S: If the speed of the fan of Example B is increased so as to produce a static pressure of 1 in. of water at the 200 F temperature, what will be the speed, capacity, and power? Fans:- 709 - Speed = 400 X a/ = 446 rpm ' 0:0602; - .- " Capacity .= 12,000 X 0:075 =' 13,392 cfin (measured at 200 F) 0.0602 ' Power = 4 X ji /-5^5. = 4.46 hp ' 0.0602 , Example 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 0.0602 0.075 .. Capacity = 12,000 X.^j^ = 14,945 cfm (measured at 200 F) . ; . h ,,. . , 0.075 : ' ; . ; ' * Static pressure = 1 X^^ = 1-25 in......... . . , /0.075 V ; Power = 4 X ( : ) =650hp > The fan laws stated may be combined to give other Overall valued: One useful combination is the product of laws ! and 3'which gives the following relations: - ' : ' .. Capacity varies as the ratio of Bize 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 12,000 cfm at' 70 F at 1 in. static1 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 m. wheel at the same speed? .. : (I)'* ......Capacity /400\ \m) x 12,000 = 23,400 cfm Static pressure = /45\* (- ) X (/4--00\1* x1 = 156 in. (4&5)\S /4OOV 1 xUJx4 = : l-22hp 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 .de sired range_.of'volumes. Figs. 2, 3 and 4 illustrate performance (some times called ' characteristic) curves of various types of fans. ' '" Centrifugol 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- 726 CHAPTER 33 ' 1952 Guide clogging dirt mat on the - filter face. High velocity filters are apt to be: adversely affected if the amount of lint in the air to be cleaned is excessive.' ; The resistance of filters increases with dust or lint loading, and it is the resistance due to this .cause 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. Manometers are often installed to indicate the pressure dropacross filter banks, and they serve to indicate when the filter requires-clean-- ing. The pressure drop tolerated differs between operators and system designs. The resistance of a filter bank can be kept desirably low byperiodically 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'use.. The frame is frequently a combina-; tion of cardboard and wire. ' ': Cleahable 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 latter 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 outsideof thesystem. 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 iri place, provision should be made to collect and. drain the water so as to prevent leakage from the filter housing. ' . '; Automatic Viscous Filters In an automatic, air filter, means are provided to remove the dust from the medium' mechanically. Automatic filters with moving cloth media have been constructed, but are not now in wide use. : The medium in a typical automatic 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 hous ing, so that the filter medium can be moved as . a continuous curtain up one side and down the other side of the sprockets. The arrangement is such that, at the bottom, the medium passes through a .bath of special oil which both serves to remove the dirt from the plates, and acts as an ad hesive when the cleaned plates next pass, through the . air stream.1 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 an auto matic 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 mo tion. In operation, the resistance of an automatic filter will remain ap proximately constant as long as proper operation is obtained. A resist ance of Yi in. water at a face velocity of 600 fpm is typical of this class. Air Cleaning 727 ; ; DRY AIR FILTERS The media' in such filters are usually fabrics dr 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 fromi 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- . Fig. 1. Diagrammatic Cross-Section of Ionizing Type ` Electrostatic Precipitator ' ciency with very fine particles equivalent to that of electrostatic precipita tion is not uncommon with certain types of dry filters. A comparatively deep-bed, to 1 in. thickness, 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:: ' ELECTRIC PRECIPITATORS Two principal types of electrostatic, precipitators 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 Electrostatic Precipitator The fact that a particle exposed to an electric field will assume a charge and migrate toward one of the electrodes, has been utilized for some years 728 CHAPTER 33 1952 Guide "in boiler plants as a means of sinoke abatement. The same principle has been used in equipment developed for air cleaning in air conditioning with out generating ozone in intolerable quantities. The air stream in a pre cipitator passes first through a relatively high-tension electric field, known as the ionizing field, and then through a secondary field where, the pre cipitation of the dust occurs. The arrangement, is as shown in Fig. 1. In a typical case, a potential of 12,000 volts may be used to create the ionizing field, and some 5000 volts between the plates upon which the precipitation of dust occurs. These voltages,, which are capable .of shock to personnel similar to that of a spark plug, necessitate some safety meas ures. A typical arrangement provides means for automatically making the unit inoperative when a door to the precipitator is. opened.. To resume operation the procedure necessitates closing the door and turning an electric switch, the latter of which should be located at a reasonable distance from the equipment. The voltages necessary for the operation of the precipita tor are usually obtained from an alternating current building service line by means of a step-up transformer. Precipitation with alternating current is possible, but is not nearly so effective, so the current is usually rectified by means of vacuum tubes. The transformer and tubes are collectively termed the power pack. . . The precipitators of this type offer negligible resistance to air flow and, therefore, care must be exercised in arranging the duct approaches on the entering and leaving sides of the precipitators in order that the air flow may be distributed uniformly over the cross-sectional area. The efficiency of the precipitator is very sensitive to air velocity, and the device itself has much less tendency to rectify the air stream than filters which have much higher resistances. In most systems, resistance is deliberately added in the form of a perforated plate attached to the air approach side of the precipitator in order to obtain a uniform distribution of air. Such plates, however, are only partially effective. The plate also serves to prevent lint agglomerates, paper, and similar foreign material from reaching the precipitator proper. Electric precipitators of the ionizing type are available in both auto matic and non-automatic types. The plates of non-automatic precipita tors are commonly coated with a light oil as an adhesive. Cleaning is accomplished with a water hose and, for this reason, the bottom of the equipment' is made water tight and provided with a drain. In one auto matic type, the grounded groups of precipitation units are mounted on chains; and are alternately dipped in oil and exposed to the air stream with an action similar to that of an automatic impingement filter. The charged precipitator plates are mounted stationary in the air stream. These plates .collect only a minor portion of the total dirt. They are cleaned and re coated with adhesive by means of a wiping device attached to the revolving chain. Charged Media Electrostatic Precipitators . The charged media type precipitator consists of a dielectric filtering medium, usually arranged in pleats as in typical dry filters. No ionization 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 gridwork consisting of alternately grounded and charged members, the latter usually, being held at a potential of 12,000 volts d.c. An intense and non-uniform electrostatic field is thus created through the dielectric medium. Airborne particles approaching the field are polarized Air Cleaning '729 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 for velocity and, unlike the ionizing type, the resistance of the charged media type electrostatic precipitator rises as dust is accumulated oh the media. Because of these characteristics the filter tends to equalize the air distribution over the face of the filter. Like typical replaceable media mechanical filters, the charged'media pre cipitator is serviced by replacing the filtering medium. ' ' 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 Fig. 2. Cross-Section Diagram of Charged Media Type Electrostatic Precipitator 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 cleaner differs with the size and nature of the dust on which'the cleaner operates. The efficiency of an air cleaner, algebraically expressed,'is where : ' U) ' D, = amount of dust per unit volume in uncleaned air. D, = amount of dust per unit volume in cleaned air. Several methods have been investigated for evaluating Di and Dj. . The 730 CHAPTER 33 1952 Guide .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 .ion 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 has found wide utility, and- was recognized by the American Society op Heating and Ventilating Engineers and incorporated in a code.4 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 accomplished 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. Air Cleaning 731 air filters. Type A is a dense pack used in bacterium:control ;Type B is a medium- pack used for general ventilation work; Type C is a low re sistance unit, for use where low resistance is the important factor and maximum cleaning efficiencies are not- essential; and Type D is a high-: velocity viscous-impingement filter. . : - :. At the National Bureau of Standards two injectors are provided on the air cleaner testing apparatus. One injector-is used to contaminate the air stream with Cottrell'precipitate, previously ^described. This dust- is-used to make both efficiency 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. 4 illustrate the difference in the characteristics of two filters, one a- viscous-impinge ment type and the-other a dry filter with a cellulose fiber medium. The two injectors can be operated either separately or simultaneously. 1200 Fig. 3. Resistance to Aik Flow oe Typical Unit Aib Filtebs The dust-spot or blackness test for cleaner efficiency was developed at the National Bureau of Standards,6 The test consists of drawing samples of cleaned air and of uncleaned air through filter papers simultaneously. :The ratio of the areas of paper through which the air samples are drawn, and the ratio of the amount of air drawn through the papers, are adjusted during successive trials to yield spots of approximately equal, blackness on the papers. The ratios of the areas and of the. volumes of the air samples are then indicators of the filter effectiveness. A special photometer is pro vided for comparing the blackness or opacity of the papers by transmitted light. For. tests of ordinary air filters by this method, a dust is injected into the air stream. The dust consists of precipitated smoke particles from a Cottrell precipitator used in a local power plant for smoke abate ment. For tests of electrostatic air cleaners, no dust is added to the air. Tests are commonly made with the dust existing in the air at the location of the installation on a clear day. . . 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 non-automatic air cleaners. Determination of dust-holding capacity is an objective of each test under the A.S.H.V.E. Standard Code.4 Curves are obtained during such tests to show the relation between dust load and resistance. Fig. 3 indicates the general range of resistance to air flow through unit For removing fine dust or liquid particles which show no gravitational' settling tendency, electrical precipitators are highly effective in air cleaning applications.' The electrostatic equipment- is comparatively expensive to install and maintain. However, in many applications where the cleanest air possible is needed, this' expense is justified by the results obtained with properly installed and operated electrostatic air filters. While the charged media type of electrostatic precipitator is less expensive to install and maintain than other types, it is still substantially more costly than the mechanical types of filters. . .. . The advantage of the automatic 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 arrestance may not be any higher. Unit filters constitute the majority of air cleaners now in use, and some choice.is possible between the types available. Where lint in an eminently dry state predominates, a dry filter obviously may be preferable to other types because of its lint-holding capacity. If the -tint is greasy, or if oil 732 CHAPTER 33 1952 Guide 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 represent the general type of air cleaner.' now in use. They have approached standards 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 automatic oil type if the resistance is to be maintained within reasonable limits. FILTER INSTALLATION Many air cleaners are available in units of convenient size for handling when installing, cleaning, or replacing. Such units are usually designated as filters or unit filters. A typical unit filter may be 20 in. square and from one to several inches thick, depending on the manufacture and.proposed use. In large systems, a number of such units are installed adjacent to each other and collectively called a bank of filters. : Air cleaners are commonly installed in the outdoor air 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 bulding. 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 depreciation as well as ex pense and convenience of maintenance. The following recommendations apply to filters (also washers) installed with central fan systems: , .' Air Cleaning 733 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 Bhould be lined with'felt to prevent infiltration of unclean air. All connections and seams, of the sheet metal ducts on the clean air side should be as air-tight as possible. 5. Electric lights should be installed in the chamber in front of and behind the air filter. . 6. Air washers should, whenever possible, be installed between the tempering and heating coils to protect them from extreme cold in winter. . 7. 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. 8. Filters should have permanent indicators to give a warning when the 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 mitted in accordance with some existing local regulations. Combustion of dust and lint on a filtering medium is possible, though the medium itself may not burn. ' `' ADSORPTION OF VAPORS OTHER THAN WATER ' Many of the foreign gases in the atmosphere are 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 60 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. Adsorbers may be applied to reduce objectionable gases entering through 734 CHAPTER 33 1952 Guide 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 2--DUST COLLECTORS Industrial development and growth of industrial areas have had a cumu lative effect upon the problem of dust control. Not . only has the atmos phere 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. 1 .. . . 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 dust collector is required. An industrial air clean ing installation is designed to perform one or more of the following func tions: '' 1. Prevent a nuisance or physical damage to a plant or adjacent property.. . 2. Prevent re-entry of contaminants, to working spaces.. ; . .3. Reclaim usable material. .. . ' ... i.'v4.. Reduce fire, explosion, or.other hazards. ... .. 5. Permit recirculation of cleaned air to working spaces. .., ' . ; . DEGREE OF DUST REMOVAL REQUIRED . v. Minimum standards of dust removal required of a dust collector may be established by local or state regulations,, prepared byrnunicipal smoke abatement or health departments, or by state labor or health departments. Regardless of minimum standards, it is good practice '.to install the most effective collection equipment available in the light, of practical operation features and installation and equipment costs. This is warranted because the required degree of effluent removal is increasing continually; ' Public nuisance complaints often occur even when the effluent concentration dis charged to the atmosphere is below the permissible limits of Concentration and visibility. Plant location, contaminants involved and meteorological conditions of the areas, must be evaluated in addition to existing regulations or cddCs of good practice. . '. .. . Air cleanliness must be of the highest order where cleaned air is recir culated to the workroom. Such recirculation is considered poor practice and is prohibited by many states where toxic materials are involved, except 'for those cases where discharge, to atmosphere is impossible or decidedly impracticable. Where air is recirculated, air contamination must not exceed the established maximum allowable concentrations listed in Chapter 8. Usual, requirements are a fraction, often to f this standard, . depending on: state involved, air quantities recirculated in relation to the .cubical Content of working space, and the presence of other exhaust systems discharging to the atmosphere. '. FACTORS AFFECTING SELECTION Selection of a dust collector for a given application requires an evaluation of the following 5 considerations: 1. Dust load and particle size of the contaminant. 2. Degree of removal required. .... < Air Cleaning 735 .3. Conditions of air or gas stream with reference to temperature, moisture content,: and chemical composition. - ..; . . - . 4. Characteristics of contaminant whether corrosive, sticky, or packing, and its specific gravity, particle.size.and shape. / . .... . . . ... .. .. 5. Methods of disposal or salvage that meet.the conditions imposed by material, process, or plant location. ... . - .' ' ` ' " . . With the range of variables that must be considered, selection of proper dust collection equipment is based largely on experience, and manufacturers , of such equipment should be consulted for their recommendations. TYPES AND APPLICATION OF DUST COLLECTORS ` Dust collectors are available in a .multiplicity of designs, frequently in volving more than .one principle of operation. Basic principles of opera tion are described in following sections. Manufacturers of various types can be found in the catalog section of The Guide, or in handbooks featuring Such equipment. , .. . .. . Electrostatic Dust Precipitators Electrostatic dust and fume collectors differ, materially from the low ! voltage designs described in Part.I of this chapter, although the principles, methods of operation and efficiencies are similar.; Fordust collector loads, it is:obvious that more severe demands are.made uponmethods of cleaning the collector, disposal of dust accumulations, and, servicing practices. Low voltage cleaners to date do,not have sufficient inherent dust holding capacity. One. exception in the field of exhaust systems, is that of the oil mist collector, which functions, satisfactorily with the, conventional. low voltage type electrostatic precipitator.. . The heavy duty dust collectors employ an assembly of parallel collector electrodes 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. The earlier high voltage collectors were made in the form of vertical pipes, and are still used for high operating pressures and for wet collector designs where water continuously flows down ward inside the pipe walls of the collector electrode. The negative dis charge electrodes or rods are accurately centered between the usual 9 in. collector electrode spacing, the latter being of positive charge. Precipita tion occurs in a single stage wherein ionization and collection are carried ' on simultaneously throughout the unit, and . depend on high potentials of 60,000 to 75,000 volts. The two-stage type which has the added primary stage of ionizer and receiving electrodes, however, fulfills some needs better than the single stage type. , .. 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 charged collector plates. Air velocities vary from 4 fps to 8 fps with negligible pres sure drops. Attention should be directed to the prohibition of air recirculation to occupied spaces. High voltage cleaning equipment produces ozone in ex cessive quantities and, in addition, develops oxides of nitrogen. Collector electrode cleaning is conveniently managed by a rapping device, either electrical or pneumatic, without interrupting operation. The dry plate surfaces release the dust readily into hoppers below the plates. For longer than two decades, electrical precipitators of the heavy duty 'j 736 CHAPTER 33 1952 Guide high voltage type have been used for the control of hazardous materials, and for nuisance abatement. They have been applied to flue gases from cement kilns, smelters and paper plants; to exhaust systems serving crushers, grinders and conveyors; to chemical and metal working plants; and to many pulverized-fuel, fly-ash applications. To date, precipitators have been used principally for elevated temperature installations, and dry products that are free of condensation or dampness. Fabric Collectors Dust collectors in this group, often known as cloth dust arresters or doth filters, remove dust by passing air at low velocity through a filter material. Cotton cloth is the usual material, although wool, glass, asbestos, and metal screen are sometimes employed. Filter velocities depend on dust concentration, particle size, and permissible vibration interval. Normally at about 3 fpm, they often are reduced to 1 fpm or lower where heavy dust loads of very fine material are involved. Velocities in excess of 6 fpm are seldom used, except in automatically vibrated sectional collectors where velocities as high as 20 fpm are frequently employed. . Collection efficiency is high, even for low micron dust sizes, when the collector is properly maintained. As collected material builds up on filter surfaces* increasing the resistance to air flow, such a system must be stopped at 4 to 8 hour intervals so that the dust load can be vibrated from the filter surfaces to reduce the pressure loss. . Filter cloth is supported in the form of envelopes or bags in a suitable steel housing. Space requirements are quite large, generally necessitating ah outdoor location. Pressure .drop is normally 2 to 4 in. water column. Material is collected dry. Fabric arresters are limited to applications where air is above the dew-point, as condensation packs the collected material with resultant high pressure drop, and prevents removal by vi bration. Temperatures should not exceed 180 F for cotton, or 200 F for wool. Wet Collectors . In a wet dust collector, the contaminant is brought into contact with a liquid, usually water, for removing the dust from the gas stream. The various available designs represent combinations of methods that make cataloging according to principles, pressure drop, or efficiency, difficult. Wet type dust collectors have the ability to handle high temperature and moisture laden gases.. The collection of dust in a wetted form eliminates a secondary dust problem in disposal of collected material. However, the use of water may introduce corrosive conditions within the collector, aiid freezing protection may be necessary if collectors are located outside in cold climates. Space requirements are nominal. Pressure losses and collection efficiency vary widely with design. . '1 1. Static Washers. These units, unlike most air washers, are designed to handle heavy concentrations of dust. Both scrubber and eliminator plates (each having flooding nozzles) are employed in addition to the bank of sprays ahead of the scrubber plates, and 2 banks of opposed sprays located ahead of the eliminators. A hopper- bottom tank with recirculating pump completes the assembly. Pressure drop is about )4 to % in. of water. Spray towers can be placed in this same group, as they consist of a tower structure with various nozzle arrangements, and usually include an eliminator section at the top. Wet glass cell washers have special sprays playing on filter cells filled with fiber glass or other filter media. Flooded eliminator plates are used to remove free mois- Air Cleaning 737 tqre from the air stream. Pressure drop is about % in. of water, and the length of the unit is comparable to that of a single stage air washer. Applications are usually limited to low dust concentrations. ,. 2. Packed Towers. Collectors in this group are essentially contact beds through, which gases and liquids pass, either concurrently, counter-currently, or in cross flow, and are used primarily for nuisance abatement of highly corrosive contaminants. The liquid usually enters at the top of the tower, while the gases may enter at the top, at the bottom, or through an open side. Water flow rates of 5 to 10 gpm per 1000 cfm (70 F volume) are distributed fre quently through V-notched ceramic or plastic weirs. High temperature deteriora- u tion is avoided by use of brick linings permitting 1600 F gases direct from furnace flues. .. ' Air flow pressure loss for four-foot beds of irregular shaped materials, such as ceramic saddles or coke, range from 1)4 to 314 in. water, with respective face area velocities of approximately 200 to 300 fpm. 3. Wet Centrifugal. A number of designs utilize a combination of centrifugal force and water contact to effect collection. In designs of this group, the collector is cylin drical, either in shape of a tower or with the axis horizontal.. Air is introduced tan gentially, and frequently directed counter-current to flow of water by baffles or direc tional plates. Water may be brought into contact with the dust particles by keeping collector surfaces washed by spray nozzles, by induced water picked up by the air, or by fall of water due to gravity. Pressure losses range from 2)4 to 6 in. water. 4. Dynamic Precipitator. This type uses water sprays within a fan housing, and obtains precipitation of the dust particles,on the wetted surfaces of an impeller with special fan blade shape. No external pressure drop is involved, although mechanical efficiency is somewhat lower than the mechanical efficiency of standard exhaust fans. 5. Orifice Type. In this type, the air flowing through the collector is brought in contact with a sheet of water in a restricted passage. Water flow may be induced by the velocity of the air stream, or maintained by pumps and weirs. Pressure losses vary from 1 in. or less in water wall spray booth collector designs, to from 3 to 6 in.' in most industrial collector arrangements. Pressure losses as high as 20 in. are used, with some collectors designed to collect very small particles. . . 6. Disintegrator. This type of unit generally consists of one or more stages, and is largely used for cleaning producer, blast furnace, or other gases where the gas is to be used in engines, and must be practically free of dirt. The spray is generally in the fan inlet, and elimination is effected largely on the fan blades and. also on the sur faces beyond. A special two-element fan is used; the air with its dust content and water spray enters one side of the wheel aiid is discharged from the inlet of the other wheel. As the air passes through the cyclonic chamber, a high degree of scrubbing action takes place. Relatively high pressure losses are encountered, with resulting high horsepower requirements. - CENTRIFUGAL DUST COLLECTORS Centrifugal collector design can be divided into four groups: 1. Cyclone Collector. This type is commonly applied for the removal of coarse dusts from an air stream, as a precleaner to more efficient dry or wet dust collectors, or as a separator in product conveying systems using an air stream to transport material. Principal advantages are low cost and low pressure drop {% to 1)4 in. water), but this type cannot be used for high efficiency collection of fine particles. 2. High Efficiency Centrifugal Collectors. These have been developed to obtain higher centrifugal force action on dust particles in a gas stream. Centrifugal force is a function of peripheral velocities and angular acceleration, and improvement in dust separation efficiency has been obtained by (a) increasing velocities through a cyclone shaped collector; (b) utilizing a skimmer or other design feature; (c) using a number of small diameter cyclones in parallel; and (d) in some unusual applications, by placing units in series. . While such collectors do not generally reach an efficiency on small particles equal to that of the electrostatic, fabric, or some wet type units, their effective collection 738 CHAPTER 33 1952 Guide range is extended appreciably beyond that of the conventional cyclone. Pressure losses of collectors in this group range from 3 to 8 in. water, colujnn. . , 3. Dry Type Dynamic Precipitator. In this type, dust is precipitated by centrif ugal force upon specially shaped blades of an exhauster:wheel,.and then conveyed through a dust, circuit in the fan casing to the dust storage-hopper. . - 4. Cinder Catching Fan. This is a special type of collector in which removal of solids is effected by a slotted scroll. - It is a fan unit which is often used for the dual purpose of dust' removal and induced draft service. SETTLING CHAMBERS While it would be possible in theory to remove dust by settling in a large chamber when conveying velocities "are reduced, to the point where the. particles would no longer be held in suspension,' such devices have little practical application in dust collecting equipment. Extreme. space re quirements and the. presence of .eddy currents1 may nullify the effective velocity. The settling chamber type of collector can therefore'be used only for removal of extremely coarse particles. Pressure' drop should be % to in, water, column, plus that necessary, to accelerate the air motion to the required conveying velocity at discharge of. the settling chamber. SONIC AGGLOMERATORS . Sonic agglomerators, now in an early stage of development, may prove to be valuable accessories in the dust collecting field. " High-intensity sound can be utilized to coagulate low-micron and sub-micron sized aerosols such as smoke, fumes, or -very fine dusts into resultant particles which are large enough to be collected efficiently with several of the'types of dust collecting equipment previously described. ' . This high-intensity sound can be created by various means such as piezo-electric crystal: generators, magnetostriction units, or-high-powered sirens which are practical at present for units with greater air flow ca pacities. For effective coagulation, a minimum sound level of 155 to 160 de cibels6.- 7t 8 is required'.. The sound frequencies used are dependent on the size of the particles to be coagulated, and may vary from 1000 cycles-per second for larger particles to far into the ultrasonic region for smaller parti cles. Fairly high dust concentrations, on the order of one grain per cubic foot of gas, are required for effective coagulation. Neither operating temperatures in the range of O F to over .1000 F, nor electrical properties of the aerosols,6 have any apparent effect on agglomeration efficiencies .. TESTING METHODS Methods pf determining the performance of industrial air cleaning de viceswill depend upon-the nature of the air contaminant, its quantity, the required accuracy of the test, and the type of air cleaning device. .The technics used in collecting the samples are the same'as those utilized in the field of industrial hygiene. ' ' ": The tests may be facilitated by feeding, uniformly, a known amount of the material to Se-removed. The performance efficiency may be calculated from the amount of material introduced, the quantities of air involved, the amount of material intercepted, and the quantity that escapes. When it is necessary to test the device under actual use, the material entering and leaving must be sampled simultaneously over a sufficiently long period of time to collect ati adequate amount for analysis. If feasible, the quantity Air' Cleaning 739 of material removed by the cleaning device during the test/period should. also.be determined. ,. . ._. . .. ' . Unusual care must-be exercised in collecting the samples to- insure that the sampling areas selected are actually representative of the' material entering and leaving the Cleaning device: With gases; vapors-and fresh fumes, this problem is not great: On' the other hand, mi^ts, dusts and aged fumes may present considerable trouble. When the material is .confined' in a duct system, it is common practice to collect the sample along the center line. The sampling tube is located .parallel with, and facing, the flow. The sampling velocity should be approximately the same as the air velocity in the duct.' With large ducts it may be desirable to make traverse tests to locate an optimum sampling position. - - . :^ REFERENCES ' ' `Bronchial Asthma.and Allied Allergic. Disorders, by S. S. Leopold and'C: SLeopold (Journal of the American Medical Association, March 7, 1925; Vol. 84, p. 731 734). ' Dirt Patterns on Walls, by R. A. Nielsen (A.S.H.V.E. Transactions, Vol. 46, 1941, p. 247): '' ' - ' - -- ...... " ; .......... - * Industrial Dust, by Philip Drinker and Theodore Hatch (McGraw-Hill Co., New York, N. Y.). ' ' ;. 4 A.S.H.V.E. Standard Code for Testing and Rating Air Cleaning Devices Used in General Ventilation Work (A.S.H.V:E. Tbansactions, Vol. 39;T933, p. 225). ` `A Test Method for Air Filters, by Richard S'. Dill (A.S.H.V.E.'Tbansactions, Vol. 44, 1938, p. 379). . ' ' ' '' . " Industrial Sonic Agglomeration and Collection Systems, by H. W. Danser and E. P. Neuman (Industrial and Engineering Chemistry, November, 1949): ' 'Sonic Agglomeration of Fumes'in Ferromanganese Blast Furnace,' by A. H. Briscoe {Heating and Ventilating, June 1950). ` '. ' ." '' 8 Elements of Ultrasonics; by S. Young White (Audio Engineering, February, 1948). .. ;. ' ; BIBLIOGRAPHY , . . Design, and Applicatipn of Oil-Coated Air Filters; by H. C. Murphy (A.S.H.V.E. Transactions, Vol. .33, 1927, p. 73). . .. .:' Operation and Maintenance ;of Air, Filters, by W. G- Frank. {Heating, Piping and Air Conditioning, May, 1931;p. 378).. . . .. , J .. . ... . .. i 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, -Healing, Piping and Air Conditioning, April, 1933,' P- 217). . - ' ... _ ' : The Economic Factors in Converting Recirculated.Air for Ventilation, by H..E. Ziel and Henry Sleik (A.S.H.V.E. Journal Section, Heating, Piping and Air Condi tioning, July, 1943, p. 367). , ,, . . ., . .. -. Operation, Maintenance of Cloth-Screened Dust Collectors, by W. F. Terry (Heal ing, Piping and Air Conditioning, May, p. 259, June, p. 304, 1933). Testing and Rating of Air Cleaning Devices Used in General Ventilation Work, by Samuel R. Lewis (A.S.H.V.E. Transactions, Vol. 39, 1933, p. 277). A.S.H.V.E. Research Report No. 1094--Air Filter Performance as Affected by 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 Den8>ty, 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 740 CHAPTER 33 1952 Guide 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. Rowlev and R. C. Jordan (A.S.H.V.E. Transactions, Vol. 47, 1941, p. 391). ~~v . A.S.H.V.E. Research Report No. 1218--Overloading of Viscous Air Filters Dur ing Accelerated Tests, by F. B. Rowley and R. C. Jordan (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 437). The Dust-Free Space Surrounding Hot Bodies, by H. H. Watson (Transactions of the Faraday Society, Vol. 32, 1936, Pt. 2, p. 1073). A New Electrostatic Precipitator, by G. W. Penney (Electrical Engineering, Jan uary, 1937, p. 159). . Electrostatic Precipitation for Aircraft, by Howard E. Corbitt and Norman J. Clark (Aero Digest, December, 1940, p. 132). Cleaning of Air and Gas by Thermal Repulsion, by Samuel C. Blacktin (Journal, Society of Chemical Industry, 68, 1939, p. 334-8, 69, 1940, p. 153-4). . Pointers on Selecting Equipment for Industrial Gas Cleaning, by C. E. Miller (Chemical arid Metallurgical Engineering, 46, March, 1938, p. 132-5). Electrical Precipitation, by W. A. Schmidt and E. Anderson (Electrical Engineer- ng, 67, August, 1938, p. 332-r338). . . . Electrostatic Precipitation for Cleaning Industrial Gases, by H. W. Wagner (Fuel Economist, 10, 1935, p. 895-9, 942-5, 971-3); ., .. Dust Precipitation, by M. Pauthenier and Mme. Moreau-Hanot (Electrician, US, August 10, 1934, p. 187-9). ., ,. Alternating Current Precipitators for Sanitary Air Analysis: II: Acid Formation in Electric Precipitators, by W. G. Hazard and Tomoyoshi Ishikawa (Journal of Industrial Hygiene, October, 1932, p. 367-70). Electrical Precipitation, by A. W. Simon and L. C. Kron (Electrical Engineering, 61, February, 1932, p. 93^-5): The Mathematical Theory of the Cottrell Electric Precipitator, by. A. W. Simon (Iron and Steel Engineering, 6, 1929, p. 143-6). . . Progress in the Art of Electrical Precipitation Since 1900, by P. E. Landolt (Trans actions, American Electrochemical Society, 51, 1927): ' ' Some Factors and Principles Involved in 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). - Electrical Engineering Features of the Electrical Precipitation Process, by G. H. Horne (Transactions, American Institute of Electrical Engineers, 41> 1922, p. 808). 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, Heating, Piping and Air Conditioning, May, 1946, p. 117). Agglomeration of Smoke, Fog or Dust Particles by Sound, by H. W. St.Clair (Industrial and Engineering Chemistry, November, 1949). . Ultra Sonics, by Ludwig Bergmann, translated by H. Stafford Hatfield (John Wiley & Sons, New York 1946). Ultra Sonics, by Benson Carlin (McGraw Hill Book Co., Inc. New York, 1949). CHAPTER 34 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. Figs. 1 and 2 show the essential construction features of conventional air washers. Intimate contact between the air and the water is secured (I) 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 several baffle type plates located across the air stream. Water is supplied at the top of the washer to spray over these plates. ' In the case of the fiber glass or metal surfaces, the water spray is usually rather coarse and at 741 742 CHAPTER 34 1952 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; ah 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. T.Typical Single-Bank Aib : Fig. 2: Typical Two-Bank Air : :Washer 1. . 1 Washer-` spray and.wetted surfaces; and the elimination of-entrained moisture from the outlet air. .Y . . ' 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:di<itated by the 'space available. Washers of nearly equal height and width' are desirable front :aii air flow 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 ft from the entering or leaving end of the washer. 'Tn addition, air washers are very often furnished with cooling coils or heating coils within thewasher chamber, and the use of these coils affects the overall length of the washer. Where increase of overall heat transfer between the air and water is 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. " . ' . ' '. ' . 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 743 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 11 - < ti -1' (1) e = humidifying effectiveness, percent. 1 <i = dry-bulb temperature, of the entering air, Fahrenheit degrees. . Is = dry-bulb temperature of the leaving air, Fahrenheit degrees: Y V = thermodynamic wet-bulb `temperature of the entering air, Fahrenheit de grees. . V. .- The following may be taken as representative humidifying or saturating effectiveness of an air washer for the conditions stated: ` , 1 bank--downstream................... ................................................... 60-70 percent 1 bank--upstream........................................................................... 65-75 percent 2 banks--downstream... .. .V... ...>.. r.l. 85-90 percent .2.banks--4 upstream and 1 downstream..!............... . . 90-95 percent 2 .banks-r-upstream.................. ... .............. 90t95 percen The humidifying or saturating effectiveness 6f a washer is dependent upon 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 hUmidiity, but does not alter .the humidity ratio (pound water vapor per pound'dry air). At a higher wet- 744 CHAPTER 34 1952 Guide Table 1. Average Maximum Water Main Temperatures* | T emp. F T emp. F State . City fa cu aS State H City State City Ala. Birmingham........... 84 Mobile...................... 80 Ark. little Rock 83 '-Aria. Phoenix.................... 82 Tucson--... !......... 80 Calif. Anaheim ............. 60 Berkeley .; .V.......... 69 Fresno...................... 80 Fullerton.............. . 76- Glendale......... ........ 68 Loe Angeles............. 80 Oakland...;............. 69 Ontario.................... 70 Pasadena.................. 82 Pomona.................... 76 Riverside........-......... 78 Sacramento............. 72 San Bernardino___ 66 ' San Diego................ 84 San Francisco......... 71 Whittier.................. '. 75 Colo. Denver........ :.......... 75 Conn.- Bridgeport............... 66 Hartford.. ;....... 73 New Haven............. 76 Waterburv........ 72 D. C. Washington..-;. 84- Del. Wilmington............. 83 . Fla. . Jacksonville............. 86 Miami ..................... 82 Tampa......... 77' Ga. Atlanta.................... 85 Macon.!.... :.\___ 80 Idaho. Boise....................,.. 60 111. .Chicago.................... 78 Cicero...........1...... 76 Evanston :............. .73 Moline........ 83 Peoria......... 67 ' Rockford.................. 59 Springfield............... 82 Ind. Evansville............... 88 Gary.......................... 75 Indianapolis............ 84 South Bend............. 61 Terre Haute............ 82 Iowa Cedar Rapids......... 78 Des Moines............. 77 Sioux City............... 62 Hans. Concordia................ 57 Kansas City........... 86 Topeka..................... 88 Wichita........... . 72 Ky. Louisville................ 85 La. Baton Rouge.-......... 85 New Orleans........... 90 Shreveport............... 88 Me. Augusta.................... 60 Md. Baltimore....... ; 75 Maas. Mich. Minn. Mo. Nebr. Nev. N. H. N. J. n. y. N. C. N. M. Ohio Okla. 80 Cambridge............... Fall River........ :... Lowell....................... Lynn......................... New Bedford.......... Salem...................... ; 70 76 50 Pa. 68 70 . 68- 5 Eugene.......,.............. -Portland.................. Altoona........... i____ Johnstown*. McKeesport.'.,..... . 60 65 74 75 74. 82 Worcester................. 76 Philadelphia 85< Detroit..................... 77 70 Pittsburgh ___'.... 86' 84 S. C. 77 Jackson.................... 56 Spartanburg........... 78 Kalamazoo......... .. 53 S: D. Rapid City 64 .Tenn., 65 82 Duluth...*................ 55. Memphis. . -............ 85 Minneapolis............. 85 Nashville................. 90 St. Paul........ .......... 80 Amarillo .. ....... :... 70 Jefferson City___ '.. 82 Austin...................... 90 Kansas City....... 84 -Beaumont................ 86 Springfield............... 82 Dallas....... .. x........... '. 86 St. Joseph................ 84 El Paso.................... 85 ' St. Louis. ..*..!........ 85 Fort Worth1 :-- . 85 Springfield............... 74- Galveston............ 90 Lincoln..................... 70 Houston........... -.... 83 Omaha...................... H5 Port Arthur/.... 83' Reno......................... 70 San Antonio........... 78 76 85 63 Utah- 44 75 65 78 Va. 75 79 73 68 80 Buffalo...................... 78 Richmond............... 85 56 Wash. 58- 74 62 New Rochelle......... 75 Spokane..*;......... 51 72 57 70 W. Va. 85 60 78 69 70 74 85 92 Winston-Salem....... 82 Albuquerque........... 65 PnovAkron........................ 76 1NCE Canton..................... 50 Cincinnati............... 84 77 84. B. C. 60 82 72 P.E.I. 83 Que. Oklahoma City___ 82 54 58 75 68 Quebec...................... 64 60 50 63 48 78 68 * These averages taken from various city water main locations, with some actual values slightly higher and some lower than values shown. Some values were supplied by H. E. Degler, Marley Company. Some 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 3. Even 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 745 point of the mixture'should move'in a direction determined by4he specific j enthalpy? of the heated spray as explained in Chapter 3. /Tf ~is possible,i by: elevating the water ^temperature, to /raise the air temperature; both< dry-bulb and wet-bulb, above the dry-bull) temperature, of'the enterihg aif.i Jii each of the methods, "1, 2/or 3, the airfeaving the ;air_ washer may i require reheating to produce iq the . conditioned spacej thqirequise& 4ry-; bulb temperature and relative humidity! . 'V DEHUMIDIFICATION AND COOLING WITH AIR WASHERS : . V. Cooling of the wef-bulb temperature of an air vapor'mixture, ca'n 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. - -- .. r '. - Both sensible and latent heat are removed in the process of 'dehumidi fication by cold spray water. Abstraction of sensible heat occurs during J the entire time that the air is/iii 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 leaying 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 stagetwnshersj 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 iqaximum 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 wafer.main averages which may be used as a guide, but? -they should be Verified from! local records. This is particularly true with -; city,water main temperatures. In the case of well water temperatures, Fig.-3 shows the apprpximate temperatures of water to be expected from wells at depths of 30 to 6() ft. . -, ' :. . ; Air washers for dehuinidifying 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 com trailer 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 to the method of, operation: (1) indirect, such as the air washer, which 746 CHAPTER 34 1$>52 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- F ig . 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 o f 30 to 60 F t 1 Spray Apparatus 747 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 separalionis 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) atomiz ing, (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 about 160 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, from 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 moisture, and cooled. It then escapes from the opening below at a high 748 CHAPTER 34 1952 Guide .velocity- in a complete.-and nearly horizontal circle. -The spray is evapo rated and the resulting vapor diffused. . This-distribution.of fine spray overthe maximum possible area promotes complete and rapid vaporization.- Spray Humidifiers. ;This type`consists of an impact spray nozzle .in a cylindrical casing , with ai 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'semcing of individual units without, af fecting the room as a whole, group control of the water and power may be employed. : : '' , :- - 1: - !:'r.''\ ' . - 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 varies'or diffusers, and a housing to enclose the various parts. " Unit humidifiers fall into four general classifications, depending ori 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. " - , . Iri 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 aff 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. : ;- i - 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 a refrigerating plant or an electric steam-generating station. This heat removal is generally accomplished by first transferring the heat of the gas Spray Apparatus 749 to cooling water in a heat exchanger' The water, if cheap or plentiful, may be wasted to the nearest sewer dr 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 .- - : r ,; . Many communities have found tbat. 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 structores 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 fine. 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 (hr) (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 ' the 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 50 times that of a spray pond, or. about 1000 times that of .-a:water-cooling tower 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 that natural air movement across the surface of the water would be re tarded, 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 nozzles are located'iii an arrangement such as shown in !Eig:`4 to Spray 750 CHAPTER 34 1952 Guide i - _ the water upwardsinto 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.* : 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 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 Spray Apparatus 751 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 42). 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 Conventional Up-Spray System Units Standard Minimum Maximum Water capacity per nozzle............................... gpm < ' 35 to 50 25 60 : Nozzles per 12 ft length of pipe.................... 6 4- 6 Height of nozzles above water level.............. ft 6 5 12 Nozzle pressure................................................... psig 6 .5 7 Size of nozzles and nozzle arms...................... in. 2- 11 2 Distance between spray lateral piping......... ft 25 13 38 Distance nozzles from pond side unfenced.. ft 25 to 35 20 50 Distance nozzles from pond side fenced....... ft 15 to 20 15 25 Height of louver fence...................................... ft 12 12 12 Depth pond basin............................................... ft 4 to 5 2-- Friction loss allowed per 100 ft pipe............. ft 1 to 3 -- --- - Design wind velocity......................................... . mph 5 3-- ATMOSPHERIC COOLING TOWERS Spray-filled 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 ' may 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 twice 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, and 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 cooling air. The spray-filled atmosoheric tower is shown in Fig. 5. 752 CHAPTER 34 . 1952 Guide :,Muchof ti}e: atmospheric water coqlingvfor refrigeration work during the past 30 years has- been done with natural-draft deck type towers, also referred to as atmospheric deck lowers,. \see Eig. 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 oyer the upper part of the structure by means of troughs, splash heads, or nozzles, and drops from deck to deck enroute to the basin:.'1 The purpose of the decks is primarily to arrest the fall of the water, to break and re-break it into drops so asto present the most efficient cooling.'surface to the air which is'passing through the tower transversely to fhe decks. The wooden dedltS also, add to the area of water surface exposed to'the air', blit since they offer resistance 1 Fig.1 5.Spray Filled Atmospheric Fig: 6.'Atmospheric "Deck. Towee Cooling Toweb . .1 , '" to the'flow of air, the number and arrangement of the'decks depend upon basic tests and operating experience.- To prevent loss of watef'bn the leeward side of fheTower, 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. In most designs the top edge of efich 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.,air beyond the open area of the tower, and tq control the quantity of air permitted to pass through the tower.' V" . . '! The efficiency of a deck tower is improved primarily by, jincreasing length pr height, or both, within limits; the, length and height increase the area of tower exposed to the wind. The improvement is. hot. directly propor tional to the change made in either case. Neither does a certain percentage Spray Apparatus 753 change of one dimension make an equal improvement ip 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 tothe 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 qf air required by any type, of cooling equipment. - As moveihent of air through the towers is obtained by power-consuming fans, it is essential that this air quantity and the draft loss be reduced to a-.mini- , mum so as to secure low operating cost. 1 : ' , 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 qf 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 combination of the spray-filled and wood-filled design is used. ' . . The forced draft type of tower (Fig. 7), has the advantages qf being suit able for corrosive waters, and having fhe fan mounted near the ground level on a rigid foundation where it is easily accessible. . . The heated air leaves the top of a forced draft tower at a low velocity and may be subject to recirculation tothe fan inlet, with consequent reduc- 754 CHAPTER 34 1952 Guide ' tion in performance. This reduction could be as much as 20 percent under certain conditions. During cold weather, recirculation may 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, startere, 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 Sprgy Apparatus 755 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. OiSTftiasriNG'ogS' 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 CONCRCTC BA&1N ' 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 offsets the additional operating expense and initial cost as compared with those of atmospheric towers. The counterfloto (conventional) type of induced draft tower has the fan located at-the top, Fig. 8, to provide vertical air movement across the filling. Air is discharged upward at a high velocity to prevent recircula tion. Another type, for small requirements, has the induced draft fan in one end (see Fig. 9) to provide horizontal flow. ' Another induced draft tower, developed for the purpose of obtaining compactness, larger capacity, increased flexibility and improved per formance, is the crossflow type. This type of tower employs multiple fans centered along the top, each fan drawing air through two cells paired to the suction chamber which is partitioned midway beneath the fans and fitted with drift eliminators that turn the air upward toward the fan outlet. This tower obtains a horizontal air movement as water falls in a cascade 756 CHAPTER 34 . 1952'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 approxiihately'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 refrigerationrequires approximately 30 gallon-deg of cooling water per'minute per .ton of refrigeration^ In atmospheric cooling towersif-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 or 7 gpm per sq ft because 6f-iBlanket^-'effect, while the capacity of the most efficient types ranges up to 9 or lO 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 Tower-for'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 fieat 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.i per cent, for 12 to 14 deg of actual cooling due to the additional- amount of cooling bysensible 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 757 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 factors3 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 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 3, Chapter 12 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 which the equipment must be designed, the cold water temperature must be chosen to place the requirement within, the effectiveness range of the 758 CHAPTER 34 1952 Guide -I ^ -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: g (hot water temperature -- cold water temperature) X 100 - 1 hot water temperature -- wet-bulb temperature of entering air . where . Et .= 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 1: 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 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 variables3 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 design 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 759 Table 3. Effectiveness of Water Cooling Equipment ... ' Cooling Equipment Water Cooling Effectiveness--Percent Minimum Typical Maximum Spray Ponds......................................... Spray Filled Atmospheric Towers.. Atmospheric Deck Towers............... Mechanical Draft Towers........... 30 40 50 50 40 to 50 45 to 55 50 to 60 55 to 75 60 60 .90 93 and interfacial surface tension of the wetted, tower areas also affect dis tribution. .. 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, arid (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-s-10-11-12 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 by Cooling Water Mechanical Equipment Btu peb Min peb Ton Refrigeration Compressor.............. .................. Refrigeration, Absorption System.................. Steam Turbine Condenser................................. Steam Jet Refrigerating Condenser................ Diesel Engine Jacket & Lube: Oil: Four-cycle, Supercharged.............................. Four-cycle, Non-supercharged..................... Two-cycle, Crank-case Compressor............ Two-cycle, Pump Scavenging, Large Unit. Two-cycle, Pump Scavenging, High Speed iNatural Gas Engine: Four-cycle.......................................................... Two-cycle.......................................................... 250 550 -- 550 -- -- -- -- -- -- _ --- Btu peb Lb of Steam _ -- 1000 1100 -- -- -- -- - -- ;-- - --. Btu peb bhp-hb __ -- -- -- 2600 3000 2000 2500 .2200 4500 4000 760 CHAPTER 34 1952 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 rthe enthalpy of the main air stream. . . ' - . . . .. ' . .... conditions 1 WATER .. L FLOW LB PER HR '' ACTIVE: ' TOWER VOLUME ^ --------v-- -- rr~: Z f* >A S air GX flow LB PER HR : . CONDITIONS 2 .' Fig. 10. Operations in a Typical ' Wateb Cooling Toweb ' 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 witfiirt the volume, is neglected, and the'usualconcepts of heat flow and mass heat transfer are applied, the equations typifying cooling tower operation are: KaV `G r1 dh h K' - K (3) and i KaV _ rl de jL ~ 2 h' -K "(4) wherev d = overall average wetted area (surface of;water drops plus wetted tower sur face), square feet per cubic foot of active tower volume. ' (?, ='weight rate of flow of air, pounds of dry air per hour. . ft = enthalpy, Btu per pound of dry ais ' Spray Apparatus 761 ' h0 = 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. . .. . ^ v e = temperature of water in tower, Fahrenheit. 9i = temperature of inlet,water,.Fahrenheit. . :!' .. : . 9t = temperature of: outlet,water, Fahrenheit.. . . . ; . .." ' ' -V =:active tower'volume; cubic feet. . ' . .. .7 " . ' .....: .. Either term -779-- or may be. called the Tower Performance Factor - : . tr - L ' . '! '' or Number of Tower Units (NTU). - ., . .. , Fig.' 11.- Temperatuhe-Enthalpy Diagram fob Air-Wateb Yapob' Mixtube Showing Operating Lines fob Example 2 ' These equations indicate that the rate of heat transfer from the water to the air defends `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. The integration of Equations 3 and 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 tfiagram ip. Fig: 11 represents the conditions for either of.the above equations.-, "fibe water is cooled from the temperature <?i to J92, arifi the enthalpy of the air film surrounding it follows,the saturation line h".... Air enters the tower at a. wet-bulb temperature of (, and an,enthalpy,of.%. ;It is heated. to an outlet wet-bulb temperature of t{, wiih, an enthalpy of Ai.. Since-the heat rejected by the water equals the heat absorbed .by the,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 fine is the.L/G ratio., . . : . ., . 762 CHAPTER 34 1952 Guide Example 'S: 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 Performance Factor; show in tabular form the successive steps 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 6 in increments of two degrees (A9 = 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, A. 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 As'increases in equal increments of 1.2 (ratip) Btu per F deg, hence. AA = A0 X g = 2X 150,000 lb 125,000 lb = 2.4. The potential for mass' heat transfer is (A' -- A,) as shown in column 4; this 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 (A* -- A.); and column 6 is calculated in a similar manner, except that the increments are two degrees instead of 2.4 Btu. Table 5. Sequence of Mechanical Integration Tower Performance Factor 1 Water Temp. 2 Enthalpy op Film ft' 1 :3 Enthalpy.or ' Air ft. 4 Enthalpy * ' 5 Aft Difference <X - An) (h* - ft.) ' (avg.) 6 Ad (ft' - ft.) (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: ... -. --= T"! ;--d*1 2.46, Tower Performance Factor. n _ jl ' - KaV * , dB ", '' . s . . .= --------- -- = 2.05, Tower Performance Factor . - . -, h A-- A* - .. - - ' ' .The results obtained in Example 2 are designated as the Tower Per foptionee 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 763 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 3, Chapter 12). 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. . 764 . CHAPTER 34 1952 Guide 7 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 plaint ;is usually affected by the quantity hnd 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 prig head pressure as a normal maximum, the limiting temperature of the ammonia in the condenser is 96 F.1 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 he less Table 6. Condenser Design Data GA8 Desired Pressure in . ' Condenser - Leaving Hot-Water v ' Temperature, Gas Temperature Fahrenheit in Condenser, '-Fahrenheit Best Average Condenser -Condenser Design' Design . Steam. ............... ... Steam........................................ Steam.................................;................. Ammonia............................................ Carbon dioxide............................ Methyl chloride.......................... Freon, F-12.................................... Freon, F-12............. .............. ......: Freon, F-12.................... - 28 in. vacuum:: 27 in. vacuum ; . .- 26 in. vacuum 185 psi* i030 psig* 102 psig* 117 psig* ' i26 psig* " - 136 psig* . . . 101.2 115.1 125.4 96.0 86.0 100.0 100.0 105.0 110.0 1 97 110 .; 120 .. 92 83 ... , : 96 : .... . 96., 1 100 ' 104 93 '' 105' 114 . - 88... 80 ' 92 93 . 97 101 : 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 capacity. Refer to Chapter 36, for information on Evaporative Condensers. In ternal-combustion engines have limiting hot water temperatures of 140 to 180 F for closed systems, and 110 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 765 : : 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 waiter circulated foreach 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 scaledorming'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 chloro- phenates (see Chapter 42). ... ... . 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' induces 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 42..?. -. . r 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-1 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, sinceevaporation at such points rapidly increases the concentration, of dissolved solids. The presence of sodium carbonate in harmful amounts is generallyindicated by a high pH of 9 to li. 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-epeed Motors. For readily adapting tower performance to tempor 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 766 CHAPTER 34 1952 Guide crease performance to any great extent, but' increases operating hazards considerably. Water-cooling towers operated in sub-freezing weather aresubject 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 10 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 I Temperature of Water Available for Industrial Use in the United States, by W- D. 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, Healing, Piping and Air Conditioning, October, 1942, p. 624). . * Cooling Tower Performance Studies, by L. M. K. Boelter (A.S.H.V.E, Transac tions, Vol. 45, 1939, p.615). ; .- 4 Summer Weather Data; Statistics, Charts, Maps, and Analysis, by J: C. Al bright, 1939. (The Marley Company, Inc., 1944). : 5 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). 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). * 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). * 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 Engineering Chemistry, April, 1941, Vol. 33, p. 467). ' 10 Graphical Method of Determining Number Transfer Units, by T. Baker (In dustrial and Engineering Chemistry, August, 1935, Vol. 27, p. 977). " Performance and Selection of Mechanical-Draft Cooling Towers, by Joseph Lichtenstein (A.S.M.E. Transactions, October, 1943, Vol. 65, No. 7, p. 779). u Performance of Small Mechanical Draft Cooling Towers, by W. M. Simpson and T. K. Sherwood (Refrigerating Engineering, December, 1946, p. 535). ' II The Evaporation of a Liquid into a Gas, by W. K. Lewis (4 .S.M.E. Transac- . tions, Vol. 44, 1922, p. 325). .. 14 Verdustungs Kuhlung, by H. Merkel (Forschungsarbeiten, No. 275, 1925). .' CHAPTER 35 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, Performance of Heating.and : Dry Cooling Coils, Overall Coefficient of Heat Transfer, Perform- .. ance of Dehumidifying CoilB, 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 entile 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 cons 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 dehumiaification 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. . For combined cooling and dehumidifying, surface, coils present an alter nate to spray dehumidifiers. For many applications it is possible, by proper selection of apparatus, choice of air velocities, refrigerant tempera . 767 768 CHAPTER 35 1952 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 codeg, wmfib- restrict the use of directexpansion coils in the air stream, and hence, loiial''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 hekt 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 -to1 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 halve 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 769 transfer, value. Numerous types of-fin arrangement are used;! the most, 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 common 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, v In other types, the spiral fin may be knurled into a shallow groove .on the. exterior of the tube. The: tube may be ex- - Spiral fins <c: O O a.. .A O O Flat continuous fins O, O oo t O; O Flat corrugated fins . . Flat squar* tins' ' Fio. 1. Types of Fin Coil1 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 cOmmbn'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 mbst-'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 A and 1 in. outside diameter; and with fins spaced three per-inch up to eight per inch. The tube Spacing generally varies from about 1$ to in. on centers; depending upon the width of individual fins and on other-considerations of performance.'' Fin spacing^should be chosen for the duty to be performed, with Special atten tion-being paid to lint accumulation and, especially in dehuthidifying, the consideration of frost accumulation. ` : ''. : Steam Coils ; For proper, performance of steam heating coils, condensate and air must contnnidusly eliminated and .the steam, must. be evenly distributed, to the iridividual tubes. This distribution is usually accomplished by indi- 770 CHAPTER 35 1952 Guide vidual'orifices in the tubes, by distributing plates and orifices in the steam header, or by perforated internal steam-distributing pipes extending into .the individual tubes. The latter arrangement has the advantage of 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 light heating lpads, is also minimized. This is especially valuable for outside air pre- ' heaters. . Water Coils ... . The performance of water coils, for heating or'cooling, depends on the elimination of air from the system and proper distribution'of water. Air Air Heating and Cooling Coils 771. 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. Fig. 2. Various Water Circuit Arrangements elimination is taken care of, in the system piping as described in Chapter 21. 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. .. Direct-Expansion Coils Coils for volatile'refrigerants 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 ' Fig. 4. Direct-Expansion Coil with Flooded System 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 heat 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 handles 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 and 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 772 CHAPTER 35 1952 Guide -the thermal valve and is discharged against the end plug in which the.individual liquid feeds are;.elosely 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-superheat- should be produced with the least possible sacrifice of active evaporat ing surface. Sometimes a single thermal, valve is used per coil: In other cases, multiple valves are used, with the coil divided:across the air flow or Air Heating and Cooling Coils -V . . - -. - : " 773 in steam heating coils, the temperature within the tubes being substantially uniform, and the mean temperature difference the same whatever the direction.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.-yalye. 'Applications.'. ' Heating coils in field assembled banks are used for a number of purposes as described in Chapter 29. They may be arranged with the air flow should be avoided, since, it offers the disadvantage of unequal load on the two parallel circuits.- V.- -. . .. ; ,, . .. Fiow Arrangement . ,... ; .. . ' The relative directions of flow of the air outside the tubes and the medium within them, influence the performance ofthe surface: ' 'There are three types of relative flow in common use:7"Fig: 8A'shows parallel-flow in 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 airand the medium in the tubes passat right angles to each other. The counter-flow arrangement is almost universally, used in brine or water coils to take advantage ofthe highest possible mean.temperature difference.for igiven entering water and air temperatures. It is klso commonly used, innoils 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 . Fio. 6. Arrangement.fob -, Pace Contbol Fig.7. Akbangement pob .. Depth Contbol verfical or hiorizontal, although the. latter is more common. For steam 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 ing air and water pockets, water heating coils are generally arranged with the tu^es horizontal. . Certain precautions must be taken against freezing. Where steam coils are used with entering'air .'below freezing temperature, throttling the'SteaUi supply may cause freezing of the condensate in the bottom of the coil, if the tubes are of the varifety not provided with internal distributing pipes or an equivalent arrangement. ... .: There.are coils available having inner distributing tubes, and having the supply mid .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 umer.tube is prevented from-freezing.,. A wide range of modulation at very lpyv temperatures without danger pf freezing, is therefore obtained. As an added precaution, with both steam.and.water coils,.the outside air inlet 774 CHAPTER 35 1952. Guide dampers are often closed automatically when the fan is stopped to avoid trouble caused by very cold outside air drifting in during off 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 fan 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 Air Heating and Cooling Coils 775 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 20.). .- . .. COIL SELECTION In the selection,of a coil it is necessary to consider several factors: . . 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. 1 ' 6. Allowable resistances in air circuit and through tubes. 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. '' .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 Chapter 9, 10, 11 and 12. 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 cases. The air quantity is infliienced'by a number of considerations. The air 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 pf 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 influ 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 low, or it may be limited by the 'maximum fan peripheral velocity which requirement- of quietness may permit. The friction through the water or 776 ` CHAPTER 35 1952 Guide "brine circuit; may be dictated by: the head available from' a givqn.Bize of pump and pump motor. As the ifan and pump motor inputs represent a refrigerating load on cooling installations, it is economical to keep themlow;' Proper performance of a surface heating or cooling coil depends upoh 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 flowj the performance as given in the manufacturer's ratings cannot usually be obtained. To obtain rated performance it is necessary that the air quantity he 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 10.Fig. Coil Arranged with : ... . Drip Trough . 11.Fig. Recirculating Sprat System : for Gleaning 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' rteam, 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 eachcase, and should be based on an economic analysis of theplkn.t ' design as a whole. No: general rule can, therefore, be laid down for the selection of heating or cooling, coils. . It is ppssible,,however, to point `out the.limits.of usual practice and to indicate the influence of the variables involved in the coil selection, , , . , . .. Heating Coils- ' " . Steam and hot water.heating coils are usually rated, within these limits: Air Face Velocity--200to 1200fpm, sometiinesup'.to 1500'fpm. 1:: Steam Pressure--2 to 200 psig, sometimes up to 350 psig. Air Heating and Cooling Coils 777 Hot Water Temperature--150 to 225 F. Water Velocity--2 to 6 fps. Individual cases may deviate widely, but the tabulation given herewith will serve as a guide to usual 'heating installation practice: Air Face Velocity--500 to 800 fpm face, 500 being a common figure.. ' Delivered Air Temperature--varies romi about 72 F for ventilation only, to about 150 F for complete heating. :; . Steam Pressure--2 to 10 psig, 5 psig being common. ' Hot Water Temperature--150 to 225 F. Water Velocity--2 to 6 fps.. . i Water Quantity--Based on about 20 deg temperature drop through a hot-water coil. ; ' .' .. Air Resistance--The. total resistance through heating coils is usually limited to from f to f in. of water gage for public buildings, to about 1 in. for factories. The selection of heating coils is relatively simple as it involves dry-bulb temperatures and sensible heat only, without toe complication of simul taneous latent heat loads, as in cooling Coils. For a given duty, entering air temperature, and steam pressure, it is possible to select several arrange ments of the same design of coil depending upon the relative importance of space, cross-sectional area, and air resistance. Cooling Coils . Cooling and dehumidifying coHs are,usually rated within these limits: ; Entering Air-Dry-Bulb--60 to 100 F. 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 F, at coil suction outlet. . Water Temperatures--40 to 65 F. ' ' .` '. Water Quantities--2 to 6 gpm per ton, or equivalent to a water temperature rise of from 4 to 12 deg. '. . .- . ' Water Velocity--2 to 6 fps. . -. .. The ratio of total to sensible heat removed varies in practice from 1.00 to aboutl.65, i.e., sensible heat is from 60 to 100 percent of total, depend ing on the application. (See Chapter 29.) Since required ratios may der 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 and 600 fpm are frequent, 600 being a common value. Refrigerant temperatures ordinarily vary between 40 and 50-F where cooling is 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 cooling coil surface-temper ature, toe coil selection is made on the basis of dry-bulb temperatures and sensible heat transfer only, the same as with heating coils. It is possible also to choose various arrangements of face area, depth, air velocity, etc., for toe same duty. . . - Dehumidifying Coils . The selection of coils for combined cooling and dehumidifying duty is more involved than for heating or sensible cooling, and requires considera tion of both dry- and wet-bulb air temperatures. It is further compli cated by the fact that the proportional amount of dehumidification required is also highly variable. The methods outlined in the section, Heat Transfer and Resistance, may be used to determine whesther-it is possible for : a coil to perform the duty required. If entering and leaving air conditions are 778 CHAPTER 35 1952 Guide Table 1. Vabious 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 Cfm per total ton__ __ 478 Face velocity, fpm.... 325 Resistance, in. water.; 0.11 Coil face area, sq ft.... 147 Coil rows dceD ______ 4 Coil evaporator temp. F deg...... 45 234 100 "" 69 31 1.45 41,700 417 423 0.27 99.0 6 45 i.; 100 69 31 ` 1.45 37,100 371 500 0.51 74.2 8 45 MOO 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 arid 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 pf 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 ! 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 in latent heat capacity. Ori 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 estiinated.load. .. . ' Sometiriaes, arbitrary air. quantities are specified for ventilation or other Air Heating and Cooling Coils 779 Table 2. Capacity Balances fob Maximum and Minimum Load Conditions Conditions Capacity in Tons . _' Total Total Sensible Latent Required at minimum load conditions---------- Same equipment balanced at minimum load Same.equipment balanced at maximum load Same equipment balanced at minimum load conditions with 38,800 Btu per hour reheat 10.90 6.62 10.90 9.85 8.38 6.62 7.90 3.86 7.90 6.58 5.05 3.36 3.00 3.26 3.00 3.26 3.33 3.26 1.38 1.98 1.38 1.50 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 faff of outside temperature or other cause, the condensing unit arid 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 fight loads. In general, freeze 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 checkirig 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. 2. The design and-surface arrangement of the coil. 3. The velocity and character of the air stream: 4. The velocity and character of the medium in the tubes. The driving force is usually taken as the logarithmic mean teinperature difference for heating or cooling without dehumidification. For combined 780 CHAPTER 35 1952 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 Dehumidifying Coils. 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 in part of the circuit, and superheating in the remainder. In spite of this, heat transfer and ratings for coils using volatile refrigerants are usually based on a refrigerant temperature corresponding to the average pressure in the coil. 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 tubes increase the total heat transfer, as against the in-line arrangement, and corrugated fins 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 coil face velocity. This bears a varied relation to the actilal'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 that 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 coil rating information may be misleading. The significant value is mass velocity in pounds per (minute) (square foot of face area) and not ciibic feet pier minute, because for a fixed volume the corresponding weight may Vary widely, depending upon the temperature and barometric pressure. . 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 portant in obtaining reliable test ratings, and in realizing rated performance in practical installations. The resistance through the coils will assist in distributing the air properly, but where the inlet duct connections are brought in at sharp angles to the coil face, the effect is frequently bad and there may even be reverse air currents through the coils. This reduces the capacity, but can be avoided by proper layout or by the use of directing baffles. . Heat 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 6 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 information 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 781 PERFORMANCE OF HEATING AND DRY COOLING COILS V The performance of heating and dry cooling coils depends in general upon: . . .7 ' 1. The overall coefficient of heat transfer from the fluid within the coil to the air it heats or cools. , , ., ,. , 2. The mean temperature difference between the fluid within the coil and the air flowing over the coil. . .. 3. The physical dimensions of the coil. , . Thus, for any one definite operating condition, the heating or cooling capacity of a given coil is expressed by the following basic formula: g% = U X ,(4W X A X N . (1) where .. . ... . .. gt = total heat transferred by the coil, Btu per (hour): (square foot of coil face . . area). .. . U = overall coefficient of heat transfer;. Btu per (hour) (square-foot of external . . coil 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 . the coil-and the.air passing over it. (This is commonly taken as the 16ga- rithmic mean temperature difference). ; , ., i A = external surface area of the given coil, square feet per (square foot of coil face area) (row of coil depth). . : ,< . N = number of rows of coil 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 design of coil can always be considered as a combined effect of three individual heat transfer coef ficients, namely: '. 1. The film coefficient of heat transfer between air and the external surface of the coil, usually given in Btu per (hour) (square foot external surface) (Fahrenheit degree mean temperature,difference).. . . '. 2. The coefficient of heat transfer through the coil material--tube wall, fins, ribs* etc. ' "' 3. The film coefficient of heat transfer between the internal surface of the coil and the fluid flowing within the coil; usually, given in Btu per (hour) (square foot internal surface). (Fahrenheit degree mean temperature difference). ... . , .. These three individual coefficients acting in series result in an overall coefficient of heat transfer in accordance with the basic laws given in Chap ters 5 and 9. For a bare pipe coil the overall coefficient of heat transfer, whether for heating or for cooling (without dehumidification), can be ex pressed by a simplified basic formula as follows: U=- 1 *+^+A /i * /. (2) 782 CIH^APTER 35 where ' ' " 1952 Guide :- ,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). . . . . . .. f-, = 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). ,ro = 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 surface. .^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 R. } ` .. f fo ... . - : (3) . For finned coils the formula* for the overall coefficient of heat transfer can be conveniently written: . . . .;/ , /i + rf. ' : ; " 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 fi and ij/ 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.r Air Heating and Cooling Coils .. 783 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 Fio. 12. Performance op Dehttmidipying 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.' In the process of dehumidification, since heat is being transferred to the coil surface by two different mechanisms (convection and condensation), it 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 9. = /,, X A X N X (at,) . (5) 9. = sensible heat transferred, Btu per (hour) (square fqot of coil'face area). <1 = dry-bulb temperature of air entering coil, Fahrenheit degrees. t* = dry-bulb temperature of air leaving coil, Fahrenheit degrees. . 1. = average temperature of coil external surface, Fahrenheit degrees. V' li. 784 CHAPTER 35 1952 Guide Ata = logarithmic mean temperature- difference between airaricEcoil surface = ti -- It h ^ t. log. 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. (which is useful for the solution of dehumidification problems and .for-the determination of '/, from test data): . . . . .. ; foANih - <,) = 0.2436(1, ti - t, log. tt -- tg ti) or. foAN 1, -- 1, 0.2436 _ get, - t. (6) where 0.243 = specific heat of humid air, Btu per (pound) (Fahrenheit degree). 6 = air mass velocity, pounds'per (hour) (square foot of coil face area). An examination of Fig. 12 will reveal that ..when U-is at the dew-point of the entering air: \! ' 1, 1# tt -- tg 11 1dpi t. -- Idpl and when U is below the dew-point: . t .--- . , , ,ll ~. 1, . 1| "--,1dpi.. It tg ti -- IdpS Therefore, Equation 6 may be written in its most useful form as h.AN \ 'ti -- Idpl , 1 tl tg 0.2436 = log. ------ = log.- ! -- Idpl It ~ t. (7) where ta = minimum dry-bulb possible without dehiimidification', Fahrenheit degrees: .1dpi = .dew-point of air entering coil,'Fahrenheit degrees. . '. . ldp; = .dewTpoint. of air leaving coil, Fahrenheit degrees. , : ; .... This equation may be used to establish a line, as A-2-3, for a given coil if /o is knownforthe coil, or it may be used to determine f0 from test data for the purpose of rating coils: Theuse of this equation for 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 have, been developed expressing the film coefficient /<> 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 785 prevalent from the edge of a fin to its center. It is therefore necessary to make tests to evaluate the combined term rifa. The term, q/0, will be written merely/0 in this discussion, as there is no necessity, for Separately evaluating ij, and because values of fa are usually applied only to the partic ular coils for which tests are made. , - The air side coefficient,/,, of a coil of particular dimensions, is an.expon ential function of the mass velocity of the air: : /,, = Z Oa ' ' (s) ' where . . fa = film coefficient of heat transfer, Btu per (hour) (square foot external surface) (Fahrenheit degree mean temperature difference between air and average surface temperature). ' ' 6 = air mass velocity, pounds per (hour) (square foot of coil face area). Z and n = constants which depend iipon 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 A, directly from the results of any wet coil test. If calculated in'this' inanner, is plotted against 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 of Z and n are extremely vari able, depending on the particular design and arrangement of the coil surface. Therefore, it is desirable that these constants be determined direptly from test data for each type of coil surface. ' Internal Film Coefficient .: : The internal film coefficient,/ which appeara in Equation 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 minimum, to keep the superheat as low as possible without carrying liquid back to the compressor, and 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 as 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 the external film temperature and the refrigerant for evaluating / in Equation 9. ,786 CHAPTER 3S i 1952 Guide where .- . ft = internal film coefficient of heat transfer, Btu per (hour) (square foot of internal tube surface) (Fahrenheit degree). --... . (, = average refrigerant temperature, Fahrenheit degrees. ' To evaluate ft 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: ' ` yo* /i,= l.s(i +100) -- (10) where V = water velocity, feet per second. . D = internal diameter of tube, inches. t = 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 fi based on the calculated surface temperature for the entire coil may be lower than those obtained by use of Equation 10, actual test 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 (f, -- (,) 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 promoters increases the value of ft 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 quantity of 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: /0 = 10.7 at 400 fpm, /, -- 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 (t -- (dpi in Equation 7 Air Heating and Cooling Coils 787. 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. ,. f0AN , (, - (apt , 102-80 , , ... . o^=log'(r^=,og-iy-=,og'12-22=2-5 ' Then substituting values for A, and"G, N may be found as follows: 10.7 X 15N = 2.5 from which, N = 6.58 0.243 X 1740 (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 (, -- (dpi for a 6 row coil. 10.7 X 15 X 6 0.243 X 1740 102-80 log, tt (dpi 2.275 This establishes values of 9.78 for 7----- ^ = B and 2.25 for (1 -- (dpi- (i -- (dpi - (3) Next, the exit air condition at 57.3 F dry-bulb and 56 F wet-bulb as.shown at B,' is found by locating a point on the load ratio line at a horizontal distance of 2.25 dry-bulb degrees from the saturation curve. . (4) The surface'temperature may now be found from Equation 7 which may also be written as .. . ........ . Bt1- (, B-1 . ; ' . where . . .. U -- tdfA B M -- tdpS 788 CHAPTER 35 /- 1952 Guide 9;78 X 573 - 102 t. =. ' 8.78 52.3 (5) The total coil'load may be calculated from the enthalpyddififfefererenncceeaacrcorsos the coil and the air quantity using the weight of dry air instead of the weight of the mixture. . , G.Xhi-ht) -,1700 (49.24 - 23,77) ' .... = 43,200 Btu per (hr) (sq ft of. face area) where , . (7. = weight of dry air. per (hour) (square foot of coil face area). hi = enthalpy of air vapor mixture entering coil, Btu per pound of dry air. hj = enthalpy of air vapor mixture leaving coil, Btu per pound of dry air. . ; r~ . AIA\ xxtocno V V. 4, D an cc V1 \ 4,// \L \ V V- \ -- V ' \ Al \ \ -v LA------------------- 155 40 i . . at * . CO " IB FtG.14; Psychbometbic Layout fob Coil Selection Using Reheat (6) The refrigerant temperature may be found from Equation 9 ' 43,200 ,' 325 " (<* " Q 15 x 6 x -- 15 . M .. : : Therefore; U = (52.3 - 22.1) = 30;2; : . .^ Thus a coil 6 rows deep, operating at a refrigerant temperature.of 30.2 F-and a face velocity of 400 fpm, 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 selected. If a coil depth of 6 rows is maintained, the exit air conditions for the coil are indi cated at point B Fig. 14 as 72.3 F. dry-bulb and 70.8 F wet-bulb, and the surface temperature will be L Air Heating and Cooling Coils 789 t. 9.78 X 72.3 102 ------ ~x8.r7;8;--' :----- = 69.0' , The coil load will be: qt = 1700 (49.24 -- 34.66) =: 24;800 Btu per (hour) (square.foot of face area) and the refrigerant temperature will be found from Equation 9: 24,800 = (t. - fr) = 12.7 ,, 325 16 X 6 X. 77 ` . 15 Therefore, U = 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 will 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. LETTER SYMBOLS USED IN CHAPTER 36 :... . it = fin efficiency. ' ' ' :( ` A = external area of coil, square feet per (square foot of coil face area) (row . of coil depth). . ... n tl fdpi - ' - - . . tt -- idpl . ; . . D = internal diameter of tube, inches. . ". . . G = air mass velocity, pounds per (hour) (square foot of coil face area). . (? = dry air mass velocity, pounds dry air per (hour) (square foot of coil face area). . . ............... fi = 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). hi = enthalpy of air-vapor 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 wallf inches. N = 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/,,. The value of n is the slope of the line. . .. ?. = sensible heat transferred, Btu per (hour) (square foot of coil face area). 9t = total heat transferred by coil, Btu per (hour) (square foot of face area). R = ratio between external and internal surface of tube. t = average water temperature, Fahrenheit degrees, fi = dry-bulb temperature of air entering coil; Fahrenheit degrees, fj = dry-bulb temperature of air leaving coil, Fahrenheit degrees. t = minimum dry-bulb temperature possible without dehumidification, Fahr enheit degrees. . fdpi = dew-point of air entering coil, Fahrenheit degrees. . 790 CHAPTER 35 . 1952 Guide -- (dpt = dew-point of air leaving coil, Fahrenheit degrees. t, -- average refrigerant temperature; Fahrenheit degrees. t. = average temperature of external surface of coil, Fahrenheit degrees. ' Afm = mean temperature difference, between fluid in coif-and air passing over . coil, Fahrenheit degrees. -" . Note: Atm is usually the logarithmic mean. Af0 = 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 /0. ... .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). . 1 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.VJE.,Journal Section, Heat ing, Piping and Air Conditioning, June, 1946, p. 111). ' * Maximum Rate of Heat Transfer with Minimum 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 36 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 per 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 hour, by 12,000. In equation form: Hi - (Btu per hour heat gain) + 12,000 (1) where Ht = 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 modem refrigeration systems use a liquefi able vapor as the workihg substance. By altering the pressure of the refrigerant its boiling temperature is changed, allowing the material to boil in the evaporator at a temperature sufficiently lower than that of the con ditioned space, to insure maintenance of an effective heat transfer rate from 791 792 CHAPTER 36 1952 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, thehighpressure liquid refrigerant is reduced in pressure and again allowed to-boil in tiie evaporator. In order to permit'evaluation of the effectiveness with which any given cycle operates, some term is desirable which would 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. If 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 refrigerating machine, because all mechanical shaft work required to operate the compressor is dissipated as Useful heat through the condenser. The Carnot 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 in an actual machine because of the impossibility of obtaining complete reversi 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 where (CP) - T` Tt-T. (2) T. =* evaporator temperature, Fahrenheit degrees, absolute. Te -- condenser temperature, Fahrenheit degrees, absolute. .' With the ideal Carnot cycle operating as a heat pump, the coefficient of performance is . (CP) Pc Pc - T, (3) The Carnot cycle coefficient of performance for both a refrigerating machine and a heat pump increases as the spread between the evaporator and the condenser temperatures decreases. In general, the same is true for an actual system operating as either a refrigerating machine or a heat pump. Refrigeration 793 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 low-to-high temperature range can be achieved with only a moderate change in ratio. A further consideration, from the standpoint of practical operating effectiveness, is that the suction pressure should not be below atmospheric (to prevent leakage of air into the refrigerant lines) nor should the condenser pressure be 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. Fig. 1 presents a pressure-enthalpy chart for dichlorodifluoromethane (Freon-12). Although tabular arrangements of refrigerant properties require interpolation be tween 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), monochlorodifluoro-" methane (Freon-22) and monofluorotrichloromethane (Freon-11); the first two of these are commonly used in reciprocating compressors; the last refrigerant is used in centrifugal machines. 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 to 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 60 F superheat means, not that the 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, F-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 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 794 CHAPTER 36 1952 Guide O 'O OO <j 2 Horn 3Mvnos add scmnod - 3anss3ad nmossv O O O o O OOOOOO O tf oooooo OOOOOO O V "o o" <o -* n> o 0 on ^ - - -a -*S{ ^ --o * SCALE.CHANCE O O oo O S.o o o o _ H3N! 3HVn0S W3d SONOOd - 3Wns^3bd 3J/nOS0V 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 795 Table 1. Properties of Dichlorodifltjoromethane (F-12) Temp. F Prsb. La per . Sq In. liquid . Vapor- Enthalpy and Entropy Taken From --40 F. . Enthalpy . Entropy `25 F Superheat . 50 F Superheat. liquid Vapor' liquid Vapor* fiithalpy Entropy Enthalpy Entropy 0 2 4 $ 6 8 10 12 ' 14- 16 18 20 . 22 24 .26 .28 30 . 32 34 36 . 38 39 40 41. 42 44 46 / 48 50 ;52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 - 86 88 90 : 92 94 96 98 100 102 104 106 108 110 U2 114* 116 118 120 122 124 126 128 130 132 134 136 138 140 23.87 24.89 25.96 26.51 27.05 0.0110 0.0110 0.0111 0.0111 . 0.0111 28.18 29.35 30.56 31.80 33.08 C.011L 0.0112 0.0112 0.0112 0.0112 34.40 35.75 . 37.15 38-58 40.07 0.0113 0.0113 0.0113 0.0113 0.0114 41.59 43.16 44.77 46.42 48.13 0.0114 0.0115 0.0115 . 0.0115 0.0116. 49.88 -50.78 51.68 52.70 53.51 0.0116 0.0116 0.0116 0.0116 0.0116 55.40 57-35 59.35 6129 63.49 0.0117 0.0117 0.0117 0.0118 0.0118 65.63 67.84 70.10 72.41 74.77 0.0118 0.0119 0.0119 0.0119 ' 0.0120 77.20 79.67 82.24 84.82 87JO 0.0t20 0.0120 . 0.0121 0.0121 0.0121 99JO 93.00 95.85 98.76 10L70 0.0122 0.0122 0.0123 0.0123 * 03)123 104.8 111017..19 114-3 117.7 0.0124 0.0124 0.0124 0.0125 0.0125 121/) 124-5 128.0 131.6 135.3 0.0126 03)126 0.0126 0.0127 0.0127 139.0 142J 146.8 isa? 1544 0.0128. 0.0128 0.0129 0.0129 ' . 0.0130 158.9 163.1 167.4 17L8 1762 0.0130 . 0.0131 0.0131 0.0132 aoi32 1802 185.4 190.1 194.9 1992 ' 0.0133 0.0133 0.0134 0.0134 0.0135 2042 209.9 215JO 2202 0.0135 0.0136 0.0137 03)138 1.637 1.574 1.514 1.485 1.457 1.403 1251 12011253 l.?07 1.163 1.121 1.081 IMS' .1.007 0.973 0.939 0.908 0277 0248 - 0219 . 0206 : 0.792 0.779 , 0.767 0.742 0.718 0.695 0.673 0.652 0.632 0.612 0.593 0275 . 0257 0240 0224 0208 0.493 0.479 ~ 0.464 0.451 0.438 0.425 0.413 0.401 0-389 0.378 0-368 0-357 0247 0-338 0228 0219 0310 0302 -0293 0.285 . 0277 0269 > 0.262 0254 .0247 0240 0.233 0227 0220 . 0214 0.208 0.202 0196 0191 0185 0180 825 7821. .8.67 78.44. 9.10 " `78.67. 922 7829 923- 78.90 0.01869 0.01961 0.02052 0.02097 0.02143 . 9.96 10.39 1022 11.26 11.70 79.13 7926 7929. 7922 -80.05 0.02235 0.02328 0.02419 0.02510 0.02601 12.12 80.27 ` 0.02692 .1225 8049 0.02783 13.00 8072 . 0.02873 13.44 - 80.95 0.02963 1328.* 81.17' 03)3053 1422 14.76 1521 15.65 1610 8129 81.61 8123 82.05 82.27 0.03143 0.03233 0.03323 0.03413 0.03502 1625 16.77 17.00 1723 17.46. 82.49 82.60 82.71 8222 82.93 0313591 0.03635 0.03680 0.03725 0.03770 17.91 18-36 1822 1927 19.72 83.15 8326 8327 83.78 83.99 0.03859 0.03948 0.04037 0.04126 0.04215 20.18 20.64 21.11 2127 22.03 8420 84.41 84.62 8422 853)2 0.04304 004392 0.04480 0.04S68 03)4657 22.49 22.95 23.4223.90 2427 2424 2522 2520 2628 26.76- 85.22 85.42 85.62 8522 86.02 8622 86.42 86.61 8620 86.99 0.04745 0.04833 0.04921 0.05009 0.05097 0.05185 03)5272 0.05359 0.05446 0.05534 2724 27.72 2821 28.70 29.19 87.18 8727 8726 87.74 87.92 0.05621 0.05708 0.05795 0.05882 0.05969 29.68 30.18 3067 31.16 3125 88.10 88.28 88.45 88.62 88.79 0.06056 0316143 0.06230 0.06316 0.06403 32.15 32.65 33.15 33.65 34.15 88.95 89.11 .89.27 89.43 8928 0.06490 0.06577 0.06663 0.06749 0.06836 34.65 35.15 35.6S 36.16 36.66 89.73 8927 90.01 90.15 9028 0.06922 0.07008 0.07094 0.07180 0.07266 37-16 37.67. 38.18 38.69 39.19 9040 9022 90.64 9C.76 9026 0.07352 0.07437 0.07522 0.07607 0.07691 39.70 4021 4072 4124 9096 913)6 91.15 9124 0.07775 03)7858 0.07941 03)8024 0.17091 0.17075 0.17060 0.17052 0.17045 81.71 0.17829. ,8526 81.94.. 0.17812 .8521 `82.17 0.17795 ' 85.76 82.29 0.17786 8529 82.41 0.17778 86311 0.18547. 0.18529 0.18511. 0.18502 0.18494' 0.17030 82.66 0.177630.17015 82.90 . 0.17747 0.17001 83.14 . 0.17733 0.16987 8328 0.17720 0.16974 ..-83.61 0.17706 86.26 0.18477: 8621. 0.18460 86.76 0.18444.87.01 0.18429- ;8726 ai8413. 0.16961 0.16949 0.16938 0.16926 0.16913 8325. 84.09 8422 8425 '84.79 0.17693 0.17679 0.17666 0.17652 027639 8721 .87.76 88.00 ` .8824 88.49; 0.18397 0.18382 0.18369 0.183550.18342 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 0.18328 88.97- 0.18315 8921 0.18303 89.45. 0.18291 8928 0.18280 0.16843 0.16838 0.16833 0.16828 0.16823 86.18 8629 86.41 8622 86.64. 0.17566 0.17560 0.17554 0.17549 0.17544 89.92 -.90.04 90.16 . 90.28 90.40 0.18268 0.18262 0.18256 0.18251* 0.18245 0.16813 0.16803 0.16794 0.16785 0.16776 86.86 -87.09 8721 8724 . 87.76 0.17534 0.17525 0.17515 017505 0.17496 90.65 9029 . 91.14 9128 . 91.61 0.18235' 0.182240.18214 0.18203 0.18193 0.16767 0.16758 0.16749 0.16741 0.16733 87.98 88.20 88.42- 88.64 8826 0.17486 0.17477 0.17467 0.17458 0.17450 9123 . 923)6 `9228 9221 92.74 at8i84: 0.18174 ai8165 0.18155 0.18147 0.16725 0.16717 0.16709 0.16701 0.16693 89.07 89.29 8920 89.72 89.93 0.17442 0.17433 0.17425 0.17417 0.17409 9227 9320 93.43 9X66 9349 0.18139. 0.18130 0.18122 ai8ii4 0.18106 0.16685 0.16677 0.16669 0.16662 0.16655 90.14 90 36 9027 90.78 90.98 0.17402 0.17394 0.17387 0.17379 0.17372 94.12 9424 9427 9420 95.01 ai8098 0.18091 a18083 0.18075 028068 0.16648 91.18 0.16640 9127 0.16632 9127 0.16624 91-77 0.16616 9L97 0.17365 0.17358 0.17351 0.17344 0.17337 9522 ai8061 95.44; 0.18054 95.65 0.18047 9526 0.18040 96.07 0.18033 0.16608 0.16600 0.16592 0.16584 0.16576 92.16 9226 9225 92.75 92.93 0.17330 0.17322 0.17315 0.17308 0.17301 9628 9620 96.71 96.92 97.12 0.18026 028018. 028011 028004 027998 0.16568 0.16560 0.16551 0.16542 0.16533 93.11 9320 93.48 93.66 9322 0.17294 0.17288 0.17281 0.17274 0.17266 9722 9723 97.73 97.93 98.11 027993 027987 027982 0.17976 027969 0.16524 0.16515 ai6505 0.16495 0.16484 93.98 94.15 94.31 94.47 94.63 ai725S 0.17249 0.17241 0.17233 0.17224 9829 98.48 9826 9824 '99.01 027961 027954 0.17946 027939 027931 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 9925 9923 99.70 9927 0.17922 0.17914 027906 0.17897 027889 0.16411 0.16396 0.16380 026363 9526 95.72 9527 96.03 G.17166 0.17156 ai7145 0.17134 100.04 10022 10029 10026 027881 0.17873 027864 027856 796 CHAPTER 36 1952 Guide of refrigerant which is present in vapor form. Consider, for example, F-12 with a quality (the percent in vapor form) of 30 percent; the enthalpy of this material would be equal to __ where ha = A, + 0.30 (A, -hi) ; (4) ' . Am = specific enthalpy of the mixture. . hi '= specific enthalpy of the liquid. h, = specific enthalpy of the saturated vapor. ' . . ' " Values of hi and hr are obtained from Table 1 for the actual pressure of the mixture. .. 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 pa is discharged. The quality of the material at discharge is then determined by making use of the fact that the expansion process is completely irreversible, is a throttling process, and hence, occurs without change in enthalpy. Thus, the enthalpy, of the mix ture, Am, is equal to the enthalpy of the saturated liquid at the entrance state, ht., and can therefore be read from the table. ' Thus, . his = Am = hrd -- (1 l) (Ayd Afd) (5) or, x = (Am -- Afd) + (Avd -- Afd) (6) where hi. =? enthalpy of saturated liquid at entrance to expansion valve. Am = enthalpy of mixture. hri = enthalpy of saturated vapor at discharge. Aid = enthalpy^of liquid at discharge. x = proportion of liquid in the mixture, decimal. ' . .' . . Vapor Compression Refrigeration Cycle Simple Cycle. The refrigerant cycle is the series of state changes (which occur in the conditioning processes) needed to restore the refrigerant to a condition in which it will possess the ability to extract heat from the space to be cooled. For all compression-type systems the cycle consists oif four processes: heat gain in the evaporator; pressure rise in the compressor; 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 ah expansion valve. Basically, then, 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. Refrigeration 797 Table 2. Pbopebties of Monochlobodifluobomethane (F-22) , Sat Temp F Abs Press Lb per Sq In. Volume. Enthalpy and Entropy Taken from -40 F Enthalpy Entropy 50 Dec Superheat 100 Dec Superheat Liquid Vapor Liquid Vapor Liquid Vapor Enthalpy En tropy Enthalpy ' En tropy 0 38.79 0.01192 1.373 io.63 105.02 0.0240 0.2293 112.35 0.2446 120.00 0.2590 ' 2 40.43 0.01195 1.320 11.17 105.24 0.0251 0.2289 112.59 0.2442 120.26 0.2586 4 5 86 42.14 43.02 43.91 45.74 000...000111221009108 0.01205 1.270 11..222416 1.175 11.70 11.97 12.23 12.76 105.45 105.56 105.66 105.87 0.0262 0.0268 0.0274 0.0285 0.2285 0.2283 0.2280 0.2276 112.83 112.95 113.07 113.31 0.2438 0.2436 0.2434 0.2430 120.52 120.65 120.78 121.04 0.2581 0.2579 0.2577 0.2572 10 47.63 0.01208 1.130 12 49.58 * 0.01211 1.088 13.29 106.08 0.0296. 0.2272 113.55 0.2426 121.30 0.2568 13.82 106:29 0.0307 0.2268 113.79 0.2422 121.56 0.2564 14 5149 0.01215 1.048 14.36 106.50 0.0319 0.2264 114.02 0.2418 121.82 0.2560 0.0122216 53.66 0.01218 1.009 14.90 106.71 0.0330 0.2260 114.25 0.2414 122.08 03566 18 55.79 0.9721 15.44 106.92 0.0341 0.2257 114.48 0.2410 122.33 03552 20 57.98 0.01225 0.9369 15.98 107.13 0.0352 0.2253 114.71 0.2406 122.59 03548 22 00.23 0.01229 0.9032 16.52 107.33 0.0364 0.2249 114.94 0.2402 122.84 03544 24 6245 0.01232 0.8707 17.06 107.53 0.0375 0.2246 115.17 0.2398 123.10 03540 26 64.94 0.01236 0.8398 17.61 107.73 0.0379 0.2242 115.40 0.2395 123.35 0.2537 28 67.40 0.01239 . 0.8100 18.17 107.93 0.0398 0.2239 115.62 0.2391 123.60 0.2533 30 32 34 ' 36 ' 38 69.93 7243 75.21 77.97 80.81 0.01243 0.01247 0.01250 0.01254. 0.01258 0.7816 0.7543 0.7283 0.7032 0.6791 18.74 19.32 . 19.90 20.49 21.09 108.13 108.33 108.52 108.71 108.90 0.0409 0.0421 0.0433 0.0445 0.0457 0.2235 03232 0.2228 00..22222225 115.84 116.07 116.29 116.52 116.74 0.2387 0.2383 0.2380 0.2376 Q.2373 123.85 124.10 124.35 124.59 124.84 0.2529 0.2525 0.2522 0.2518 0.2515 / 42 44 46 48 83.72 86.69 89.74 9248 96.10 40 99.40 62 1024 54 106.2 66 1094 68 113.5 ,W ! 62 64 . 66 68 112117.40 . 124.9 128.9 133.0 0.01262 0.01266 0.01270 0.01274 0.01278 0.6559 0.6339 0.6126 0.5922 0.5726 0.01282 0.5537 0.01286.. 0.5355 0.01290 .0.5184 0.01294- 0.5014 0.01299 0.4849 0.01303 0.01307 0.01312 0.01316 0.01320 0.4695 0.4546 0.4403 0.4264 0.4129 21.70 .22.29 22.90 23.50 24.11 24.73 25.34 25.95 26.58 27.22 27i83 28.46 29.09 29.72 30.35 109.09 109.27 109.45 109.63 109.80 109.98 110.14 110.30 110.47 110.63 110.78 110.93 111111..2028 111.35 0.0469 0.0481 0.0493 0.0505 0.0516 0.0528 0.0540 0.0552 0.0564 0.0576 0.2218 00..22221115 0.2208 0.2205 0.2201 0.2198 0.2194 0.2191 0.2188 0.0588 0.2185 0.0600 0.2181 0.0612 0.2178 0.0624. 0.2175 0.0636 0.2172 116.96 117.18 117.40 117.61 117.82 0.2369 0.2366 0.2363 0.2359 0.2350 125.08 125.32 125.56 125.80 126.04 118.02 118.22 118.42 118.62 118.82 no.oi 119.21 119.40 119.59 119.77 0.2353 *126.27 0.2350 126.50 0.2347 126.73 0.2343 126.96 03340 127.19 0.2337 0.2334 0.2331 0.2327 0.2324 127.42 127.65 127.87 128.10 128.32 0.2511 0.2508 0.2504 0.2501 0.2497 03494 0.2491 0.2488 0.2484 0.2481 0.2478 0.2475 0.2472 0.2469 0.2466 70 1374 72 1414 74 145.9 76 150.4 78 155.0 0.01325 0.4000 0.01330 0.3875 0.01334 0.3754 0.01339 0.3638 0.01344 ' 0.3526 30.99 31.65 32.29 32.94 33.61 111.49 .111.63 111111211...078158 0.0648 0.0661 0.0673 0.0684 0.0696 0.2168 0.2165 0.2162 0.2158 0.2155 119.96 120.15 120.32 120.50 120.67 0.2321 0.2318 0.2315 0.2312 0.2309 128.54 128.76 128.97 129.19 129.40 0.2463 0.2460 0.2457 0.2455 0.2452 80 82 84 86 .' 88 159.7 164.5 169.4 174.5 179.6 90 92 94 . 96 98 100 102 104 106 108 111120 114 116 118 1844 190.1 195.6 2014 2064 212.6 218.5 224.6 230.7 237.0 243.4 249.9 256.6 263.4 2704 120 277.3 0.01349 0.01353 0.01358 0.01363 0.01368 0.01374 0.01379 0.01384 0.01390 . 0.01396 0.3417 0.3313 0.3212 0.3113 0.3019 0.2928 0.2841 0.2755 0.2672 0.2594 34.27 34.92 35.60 36.28 36.94 37.61 38.28 38.97 ' 39.65 40.32 112.13 112.24 112.36 112.47 112.57 112.67 112.76 112.85 112.93 113.00 0.0708 0.0720 0.0732 0.0744 0.0756 0.0768 0.0780 0.0792 0.0803 0.0815 0.2151 0.2148 0.2144 0.2140 0.2137 0.2133 0.2130 00..22112262 0.2119 112201..0825 121.18 121.34 121.50 121.66 121.82 112221..1927 122.26 0.2306 0.2303 0.2300 0.2297 0.2294 0.2291 0.2288 0.2285 03282 0.2279 129.61 129.82 130.02 130.23 130.43 130.63 130.83 131.03 131.23 131.42 0.2449 0.2446 0.2443 0.2441 0.2438 0.2435 ' 0.2432 03429 0.2427 0.2424 0.01402 0.01408 0.01414 0.01420 0.01426 0.2517 0.2443 0.2370 0.2301 0.2233 40.98' 41.65 4232 42.98 43.66. 113.06 113.12 113.16 113.20 113.24 0.0827 0.0839 0.0851 0.0862 0.0874 00..22111115 0.2107 00..22110040 122.40 112222..5636 122.79 122.92 0.2276 0.2273 0.2270 0.2267 0.2264 131.61 131.80 131.99 132.17 132.35 0.242i 0.2418; 0.2416 0.2413 0.2411 0.01433 ' 0.01440 0.01447 0.01454 0.01461 0.2167 0.2104 0.2043 0.1983 0.1926 44.35 45.04 46.74 46.44 47.14 113.29 113.34 113.38 113.42 113.46 0.0886 0.0898 0.0909 0.0921 0.0933 0.2096 0.2093 0.2089 0.2085 0.2081 123.04 123.16 123.28 123.40 123.51 0.2261 0.2258 0.2255 0.2253 0.2250 132.53 132.71 132.88 133.05 133.22 0.2408 0.2405 0.2403 0.2400 0.2398 0.01469 0.1871 47.85 113.52 0.0945 0.2078 123.62 0.2247 133.39 0.2395 Data from Kinetic Chemicals, Inc., 1045 798 CHAPTER 36 1952 Guide - The most common and least complicated type of refrigeration cycle is called the simple saturation cycle, and is shown diagrammatically in Fig. 2 and plotted upon pressure-enthalpy coordinates in Fig. 3. For this system, 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 can be 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. Table 3. Pbopbbties op Monofluobotrichloromethane (F-ll) Sat. Tehf. y Abb. Paisa. &*peb Sq In. VOUTKB liquid* Vapor Enthalpt ahd Ektbqrt Tassh From --40 F Enthalpy Entropy 25 F Superheat 50 F Superheat liquid Vapor liquid Vapor Enthalpy Entropy Enthalpy Entropy 0 2.59 0.01020 13.700 7.81 90.4 0.0178 0:1975 93.9 0.2049 97.4 0.2120 5 2.96 0.01024 12.100 8.81 91.2 0.0200 0:1974 94.7 0.2047 98.2 0.2117 10 '3.38 0.01028 10.700 9.82 92.0 0.0222 0.1973 95.5 0.2045 99.0 0.2114 15: 3.85 0.0J032 9.530 10.80 92.8 0.0243 0.1971 96.3 0.2043 99.8 0.2111 20 4.36 0.01036 8.490 11.90 93.7 0.0264 0.1970 97.2 0.2041 100.7 0.2109 25 4.94 0.01040 7.580 12.90 94.5 0.0286 0.1969 98.0 0.2039 101.5 0.2107 30 5.57 0.01045 6.770 13.90 95.3 0.0307 0.1969 98.8 0.2038 102.3 0.2105 35 6.27 0.01049 6.080 14.90 96.1 0.0328 0.1968 99.6 0.2037 103.1 0.2103 40 7.03 0.01053 5.460 16.00 96.8 0.0349 0.1968 100.3 0.2036 103.8 0.2101 45 7.88 0.01057 4.920 17.00 97.6 0.0370 0.1967 101.1 0.2035 104.6 0.2099 50 8.79 0.01062 4.440 18.10 98.4 0.0391 0.1967 101.9 0.2034 105.4 0.2098 55 9.80 0.01066 4-020 19.10 99.2 0.0412 0.1967 102.7 0.2033 106.2 0.2097 60 10.90 0.01071 3.640 20.20 100.0 0.0432 0.1967 103.5 0.2033 107.0 0.2096 65 12.10 0..01076 3.300 21.30 100.8 0.0453 0.1967 104.3 0.2032 107.8 0.2094 70 13.40 0.01081 3.000 22.40 101.5 0.0473 0.1967 105.0 0.2032 108.5 0.2093 75 14.80 0.01086 2.740 .23.50 102.2 0.0493 0.1967 105.7 0.2031 109.2 0.2092 80 85 90 95 100 JOS ' 16.30 17.90 19.70 21.60 23.60 25.90 0.01091 0.01096 0.01101 0:01106 0.01111 0.01116 2.500 2.280 2.090 1.918 1.761 1.620 24.50 102.9 0.0513 0.1966 106.4 0.2030 109.9 0.2090 25.60 103.6 0.0533 0.1966 107.1 0.2029 110.6 0.2089 26.70 104.4 0.0553 0.1966 107.9 0.2028 111.4 0.2088 27.80 105.1 0.0573 0.1966 108.6 0.2028 112.1 0.2087 28.90 105.7 0.0593 0.1965 109.2 0.2027 112.7 0.2085 30.10 106.4 0.0613 0.1965 109.9 0.2026 113.4 0.2084 Superheated vapor from the compressor flows to the condenser where de-superheating and condensation take place. From the condenser the re frigerant 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 direct cooling of room air by the refrigerant, the system is said to be of the direct expansion type, while a system in which the evaporating refrigerant cools water or brine, which in turn cools the air, is said to be indirect. Although many differences exist between most actual systems and that of the simple saturation cycle, this latter is, nonetheless, of great value in that it provides an extremely simple method of rapidly achieving an approximate analysis of probable power requirements, compressor size, etc. Further, the equations used in analysis of a simple saturation cycle form the basis Refrigeration 799 of the more complex treatments required for compound refrigeration cycles. For these reasons a typical simple saturation problem will be worked in detail. . . Example 1: A simple saturation cycle carries a 7 ton load when operating between . suction and discharge pressure of 52.7 psia and 121 psia with F-12 as the refrigerant. Determine: (a) the cooling effect provided by each pound of refrigerant; (6) the re frigerant circulating rate; (c) the horsepower required; (d) the quantity of heat'to be dissipated from the condenser; (e) the required condenser cooling water, 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. Solution: (a) Saturated liquid F-12 at 121 psia leaves the condenser and enters the expansion valve. The enthalpy of this material (from Table l).is 29.68 Btu per 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. (6) 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, Wr = (7 ton X 200) + 53.14 .= 26.3 lb per minute. Heat of Compression ' Added to Gas (e) The horsepower required is equal to the increase in energy of the refrigerant. passing through the compressor (expressed in Btu per minute) divided by the con version factor 42.42, which is the number of Btu per minute corresponding to l hp, . (hp) = Wr (hi -- A,,) -i- 42.42 .' (7) where . hp = horsepower. '' Wx = refrigerant circulating rate in pounds per minute. ftd = enthalpy of vapor at condition of discharge from compressor. hva = enthalpy of saturated vapor entering compressor. . W, is known from (6) and hn is the enthalpy of refrigerant as it enters the com pressor in a saturated vapor state at 52.7 psia; thus ATM = 82.82. 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 is 800 CHAPTER 36 1952 Guide 0.17330, so the superheat, td, possessed by the actual gas discharged from this com pressor can be obtained .by interpolation as, . ; ted 0.16828 - 0.16608 25 ` 0.17330 - 0.16608 from which ted .= 7.6 deg. ..' . As the saturation temperature at 121 psia is 94 F the actual temperature, Id, of the vapor leaving the compressor is, td -- 94 -f- ted -- 94 -1- 7.6 = 101.6 F. By the same kind of interpolation the enthalpy of the discharged vapor can be determined from, the enthalpies given for vapor superheated 25 F and for saturated vapor, . (hd -- 88.10) (0.16828 - 0.16608) (92.16 - 88.10) = (0.17330 - 0.16608) from which, hi = 89.34 Btu per pound. Then substituting in Equation 7, . (hp) = 26.3 (89.34 - 82.82) + 42.42 = 4.03. .. . (d) The rate of heat loss from the condenser, Qc, must be equal to the sum of the energies picked up by the refrigerant in the evaporator and the compressor, <2,, = 53.14 +- (89.34 -- 82.82) = 53.14 + 6.52 = 59.66'Btu per pound or 26.3 X 59.66 = 1569 Btu per minute. This same figure can, of course, be determined more Fig. 3. Pbessure-Enthalpy Diagram for Simple Saturation Cycle directly by subtraction of the enthalpy of liquid leaving the condenser from the enthalpy of superheated vapor going into it, thus, Qe -- 26.3 (89.34- -- 29.68) = 1569 Btu per minute. (e) The cooling water rate (based on a gallon as 8.34 lb) is 1569 + (8 X 8.34) = 23.5 gpm. , _ (/) The compressor size is fixed by the volume of gas which must be drawn into the machine per unit time. Saturated vapor at 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 efficiency of 90 percent, the compressor must then displace 20.49 + 0.9 = 22.8 cfm. The speed is given as 500 rpm and, as the unit is known to be double-acting, the displacement is therefore (22.8 X 1728) (2 X 500) = 39.4 cu in. If the unit were designed so that bore d and stroke were the same, (P) + 4 = 39.4 d = 3.69 in . (g) (CP) = (h,, - hte) + (hi - K,) ' = (82.82 - 29.68) + (89.34 - 82.82) = 8.17 where hu 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 same tempera- Refrigeration 801 ture limits. Then. T, =? 501 ,F (which is 41 F + 460) and Tc = 554 F (which is 94 F +. 460) and, ' 501 (CP) = = 9.6 554 - 501 The actual cycle is therefore 8.17 9.6 or 85 percent as effective as a Carnot cycle between the same temperature limits. ' Influence of Suction Pressure Brief consideration of the analytical procedure used in discussion of the simple saturation cycle will bring out the need for maintaining the suction pressure on any refrigeration system as high as the load will permit. As the suction pressure increases, for fixed discharge pressure, the enthalpy of 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 decrease. Thus the effect of such a pressure rise is to require more work per pound of refrigerant handled, and at the same time to necessitate an increase in the refrigerant flow rate. . 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 802 CHAPTER 36 1952 Guide 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 around 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 en thalpy increase required to compress a vapor through a given pressure range increases with superheat. Further, superheated vapor leaving an evapo rator is usually an indication that the suction - pressure is lower than 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 Fig. 4. Pressure-Enthalpy Diagram fob Refrigeration Cycle with Subcooling and Superheating . 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 sub-cooling. 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. 4 shows the pressure-enthalpy diagram for a typical refrigeration cycle operating with Refrigeration 803 both 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 place within the operator's control the ability to alter the clearance of the machine, but most moderate size compressors are built with fixed clearance. By definition, the clearance is the percentage of- the volume swept by the piston, which is represented by spaces in the end of the cylinder (including valve spaces, etc.) when the piston is at the end of its stroke. Because of the trapping of high pressure vapor in the clearance space, and its subsequent re-expansion, the suction valves of the. compressor do not open until the piston has completed part 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, ' (CVE) = 100 - Fo|j^ - lj (8) where CVE = clearance volumetric efficiency. . Vc = clearance, percent of volume swept by piston, which is contained in spaces at end of cylinder when piston is at end of stroke (clearance includes valve spaces, etc.). . ' vi = specific volume of gas at compressor inlet. ' Pd = specific volume of gas at compressor discharge. 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. This results 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 tod difficult to predict the effects of these factors to any degree of accuracy comparable to actual tests. . Complex Refrigeration Cycles The preceding sections have dealt only with refrigeration systems in which there is but one evaporator; compression is accomplished through but a single stage, and expansion proceeds through a single expansion valve. In large systems or in low temperature systems in which the compression ratio is high, the compression process can be carried out in stages, with the refrigerant passing through several cylinders arranged for operation in series. The thermodynamic advantage of such compound. compression arises from the fact that intercoolers can be placed between the stages of 804 CHAPTER 36 . 1952 Guide compression to extract heat from the vapor, and thereby cause the overall compression process to approach more closely the ideal condition of iso thermal compression. Essentially, such intercoolers serve the same pur pose as a cooling jacket, but with greater effectiveness'because of the more satisfactoiy heat transfer' conditions. In the simple saturation cycle the saturated liquid entering the expansion valve commences to vaporize as soon as its pressure starts to drop. The vapor produced during the expansion process has no further use, in terms of refrigerating effect, since it has already picked up its latent heat of vaporization as a result of heat which it has extracted from the unvaporized 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 isuneconomical. With compound compression, there is at least one intermediate pressure at which flash yapor 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 can then pass. through a second expansion valve where the pressure is dropped to that corresponding to the low-pressure evaporator. The number of expansion valves is limited by the number of stages of compression.' Further cycle complications may arise if more than one evaporator is to be operated with a single compressor, and particularly, if the pressures in these evaporators are to differ. The most common solution is to operate the 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. This permits these evaporators to operate at higher pressures and, there fore, higher temperatures than those corresponding to the compressor sucrion conditions. However, this is accomplished only with a loss of power, since all of the refrigerant from all of the evaporators must be compressed through the maximum lift from the lowest pressure 'in the System. The Air Cycle System : Air cycle refrigeration, one of the earliest forms of cooling, became obsolete for many years because of its low coefficient of performance and -high operating costs. Recently, however, it has been applied with success to aircraft cooling systems where, with low equipment weight, it can utilize a portion of the cabin air supercharger capacity. It is unique among refrigeration systems in that the refrigerant remains in the gaseous phase throughout the cycle. Fundamentally, the air cycle is essentially the same as the vapor cycle. Compression is accomplished by a reciprocating or 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 much greater drop in air temperature is accomplished if the expansion is controlled to approach the isentropic by replacing the valve with an expansion engine or turbine. Furthermore, the work recovered by such an expansion engine can be utilized to supply part of the work of compression or to drive other devices. .. It is a common misconception that aircraft flown at high altitudes do Refrigeration 805 not require comfort cooling.. With pressurized cabins the work of com pression results in an air temperature increase which, , when added to the heat supplied by ram effect, solar radiation, electrical and mechanical equipment and the occupants of .the .plane, may make the conditions in tolerable without comfort cooling. At 600 mph, the ram temperature effect of stopping the air relative to the plane will result in an entering air temperature of 164 F when the ambient air is at the standard Army summer sea level design temperature of 100 F. At 1000 mph, the entering air tem perature is almost 280 F. Air cycle systems are used in practically every jet fighter and many modem commercial passenger planes flying today. In comparative studies1 made during the design of the cooling system for one large commercial airliner, it was shown that an air cycle system was much lower in both weight and space requirements than either a vapor compression or dry ice system. It had the further advantages of ease of repair and the use of a completely non-toxic refrigerant. The weight, for example, was reduced from approximately 60 lb per ton for a vapor compression system, or an initial weight of 130 lb per ton for a dry ice system, to approximately 25 lb per ton for an air cycle system. The usual disadvantage of high power requirements for the operation of the air cycle system was shown to be more than offset by the reduction in fuel requirements for transporting the bulk and weight of the cooling system through the air. Quite possibly, with continued development and further experience, air cycle refrigeration systems may be used economically for other applications, particularly in the transportation field. The Steam Jet System The steam jet system, under certain circumstances, is desirable for use in air conditioning.* Steam supplies directly the power used for com pressing the refrigerant, thus eliminating the losses connected with other methods of supplying energy. As 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 must be condensed. The steam jet system functions on the principle that water 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. A diagrammatic representation of a typical steam ejector water cooling system is shown in Fig. 5. The figures correspond to an average repre sentative system. The water to be cooled enters the evaporator and is cooled to a temperature corresponding to the vacuum maintained. Be 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 the water 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 through the evaporator, amounting to approximately 11 lb per (hr) (ton) of refrigeration developed. The remainder of the water at the desired 806 CHAPTER 36 1952 Guide 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 conT 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 5. to 200 psig, and condenser water temperatures as high as 90 F. The Refrigeration 807 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 utilises 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 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 boostersteam pressure to 10 psigincreases the steam consumption by approximately 72 percent over that required at 200 psig. The capacity of a steam jet system is usually controlled by controlling the number of boosters in use since the unit usually has several boosters operating on the same evaporator. Usually one booster is automatically controlled, whereas the others are manually operated. The capacity is dependent, as for all compressors, upon the evaporator temperature, or in other words, the suction pressure. For example, the capacity is lowered approximately 17 percent if the evaporator or chilled water temperature is lowered from 50 to 45 F. The capacity therefore can be controlled to some extent by regulating the evaporator temperature. Fig. 6. Closed Absobption 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 available in bibliography item A, and a discussion of various absorbents is given in bibliography item F. Thermodynamically, the effectiveness of a refrigerant-absorbent combination increases , directly with its negative deviation from Raoult's Law. : Fig. 6 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 refrigerant vapor as it goes into solution), then through the condenser, and finally through the rectifier. Refrigerant from the evaporator enters the absorber where it goes into solution in the absorbent; the high concentration solution is then pumped to the generator where heat is supplied; the refrigerant (with some absorbent vapor) leaves for the rectifier and the warm low concentration solution is returned to 808 CHAPTER 36 1952 Guide l- the absorber. In the rectifier selective condensation occurs, the concen tration .of the . absorbent in the condensate being much greater than its 'concentration in.the entering..vapor mixture; rectifier condensate is dripped ;.b^ku^b^the.generator. ' ; ; ;,The. ratio of refrigerating effect to heat input (the performance ratio or commonly used efficiency measure of absorption machines) is only 40 to 45; percent .with the ordinary ammonia absorption system and, aside from the inherent disadvantages , involved in the use of a toxic and explosive refrigerant, this is not . sufficiently high to make it competitive with other types of systems when used in air conditioning applications. Therefore, recently, several absorption systems using hygroscopic brines of salts such as lithium chloride or lithium bromide' (solids in the pure state) as absorb ents and water as the refrigerant have been developed. Such systems are limited to higher temperature applications but,.thermodynamically,,have Fig. 7. Diagram of Lithium Bromide Water Absorption System the advantages of a refrigerant with a high latent heat of vaporization and nonvolatile absorbents with a large negative deviation from Raoult's Law. None of. the absorbent is carried off with the refrigerant from the generator and the performance'ratio ranges as high as 75 percent. Both the refriger ant and the absorbent are non-toxic and non-explosive and the performance ratio does not vary greatly between 20 percent of capacity and full load. This increased efficiency places operating costs in competition with other forms of refrigeration in many high temperature applications such as air conditioning. One- form of lithium-bromide-water absorption system is shown sche matically in Fig. 7 with the generator and condenser shown located in a high pressure shell and the evaporator and absorber in a low pressure shell. The water to be cooled flows to the evaporator 1 from the load where a small portion of it is flashed into vapor thus cooling the remaining water which is then returned by pump 2 to the load. The pressure in the low side shell and, therefore, the temperature of the water passing through the shell is controlled by the temperature and concentration of the lithium Refrigeration 809 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 delivered back to the low pressure shell. Heat applied at the generator 7 boils off the water vapor earlier condensed in the absorber and returns the brine to its original concentration. The condenser 8, also located in the high pres sure shell, liquifies 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 pier 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.' If the peak load factor is low as compared with a long period of operation, such as in a restaurant, or if the hours of operation are short but the usage factor high, as in a church, then it is possible to consider storage refrigeration. This method of accumulating refrigeration frequently makes it possible to use low cost off-peak electric power! Power costs may also be reduced by H e a t P om p H e a t Sources A nd Sin k s 810 s s <8 8 HI* < B S' < 8H < . ao< d: 00 ta a .< & H>< 6 Bt . < H eat Source . Well Water .' Earth. Source Classification S u ita b ility as H eat S in k . . A va ila b ility ' P rim ary Good U niversal . C ontinuous . ' ` ' * P rim ary or auxiliary P rim a ry . ' P rim a ry . Good .. Good ' ' G ood . - V a ria b le w ith source P rim a ry o r a u x ilia ry' P rim ary or ,auxiliary ^ A u xilia ry * U sually poor . ' None / "... C ities . U ncertain . ; Ibtre . . L im ite d . , . ' Extensive ' . U niversal ` . (Location) . A vailability (Tim e) C ontinuous-^xcept local shortages C ontinuous-- unless C ontinuous ' well runs d ry ' ; V a ria b le ' C ontinuous, tem pera . ture level _ drops - fro m a m a x im u m to` a m inim um .as heat In te rm itte n t. r U npredictable, except over *' extended ' is rem oved,- s lo w ly - i. itim e ' .. .rises w hen p u m p is inoperative . ' 1 , .. E xpense (O rig in a l) L o w ,, less th a n earth and w ater pourcee ex cept city . Expense (O perating) ' R e la tive ly low U sually lowest H igh, usually prohibi tive - ' U sually satisfactory V ariable w ith loca tio n (10 to 25 F Deg) U sually adequate M oderate . Excellent A ir, earth ` 8cale'on coils. Local use restrictions d u r in g shortages. Die* poeal. W ater tern-, perature m ay be come too low to per m it fu rth e r heat ro. m oval. ' H ig h , re s u lt o f d r illin g L o w " __' j V a ria b le ; H ig h , u s u a lly lees th a n U nexplored w e ll ' ' :v the cost o f d r illin g a w ell . . . Low to m oderate ' R e la tive ly low' R e la tive ly low R elatively moderate U n e x p lo re d . Prom ising, . as ' ' auxiliary for reducing oper Tem perature (Level) Tem perature (V a ria tio n ) Design In fo rm a tio n Favorable 75-95% of tim e in m ost of U. S. " Extrem e Inadequate Satisfactory . . Satisfactory U sually good In itia lly good-rdrops ating coat E x c e lle n t CHAPTER 36 w ith tim e and rate of heat w ithdraw al Sm all U sually adequate M o d e ra te U sually ade- ' quate U sually moderate Large-- lees th a n fo r air, however . A d e q u a te if source is In a d e q u a te . Extrem e . P ractically . available oonstant in supply and tem perature ` Suso o f E q u ip m e n t A daptability to Mass P Sources irto ductio may n Augment 8pecialProblem e P articularly bulky Excellent, can be factory assembled and tested Least heat available when demand great est. Coils m ay become frosted requiring extra capacity, alternate source, or standby heat. M ay require d u c t w ork. -Variable a ir tem perature makes control difficult. Moderate (except w ell) Moderate Excellent, (except well) Excellent Variable (usually . M oderate (except P ro b a b ly . m oderate) ground coils) * b u lk y Poor. Fair / ' ,/ A ir, water A ir, earth, ' w a te r Corrosion*, scale m a y ` form on heat trans fer surface.Disposal. W ater location, tem perature, com posi tio n usually un k n o w n .u n til well d rille d . Well m ay ' W ater m ay cause - scale, oorro- sion. and algae fouling. U sually scale form ing or L im ite d b y local gool- P ro b a b ly w ill . corrosive. O ften in - 1 ogy and clim ate. In require heat s u ffic io n ts u p p ly . V ery s ta lla tio n costs d iffi storage equip* lim ited application, c u lt to estim ate. Re raent a t e ith henoe requires in d i quires considerable er `e va p o ra to r vid u a l design. ' ground area, m ay or oondenser damage law ns, gar side. . dens. - run dry. 1952 Guide Refrigeration 811 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 "warming 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 cycle, 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 during the past four years and, consequently, at the present time there are several hundred residential in stallations and probably a greater number of commercial systems. . How ever much research is needed before the residential heat pump installation can successfully emerge to compete economically and wifi 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 .arid 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 be 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 to water, earth to air, and earth to water. In addition, it should be recog- IL* 812 CHAPTER 36 1952 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 pUssibility 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. Exhaust tir fan 'Conditioned ak (an Exhaust air fan Conditioned air fan A typical arrangement of a heat pump system with air as the heat, source is shown in Fig. 8. ' . 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 tiie 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 813 in current technical magazines should form sufficient information for those interested in the development of this type of heating. . BASIC REFRIGERATION EQUIPMENT Compression Refrigeration Maciunes . 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 the centrifugal compressor; an ejector may be used as in the steam jet refrigeration cycle; or absorption of a low pressure refrigerant gas in a secondary fluid, followed by the absorbent's release upon application of heat, may be utilized. A detailed discussion , of the equipment required for each of these types of systems is beyond the scope of this chapter. For a more comprehensive treatment, reference may be made to the bibliography. The present discussion is limited to positive displacement 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 (i.e., 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 oh 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 Bpeed (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, thiB 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 sealed with a bellows type crankshaft seal. Horizontal double-acting compressors operate with a sliding piston rod, moving back and forth through a stuffing box. If the motor is direct-drive and enclosed within the compressor housing, the compressor is classi fied as closed or hermetic. This eliminates the necessity of any shaft seal, and not only 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 the lubricating oil. Compressor Valves. All refrigeration compressor valves are dependent for their 814 CHAPTER 36 1952 Guide ^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 the evaporator or condenser-operating pressures requires a.change of valvesetting. 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 815 Centrifugal Compressors . Centrifugal compressors are used with very low pressure refrigerant; , usually both evaporator and condenser work below atmospheric pressure. Water and monofluorotrichloromethane (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;large 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 2 nd stage compressor Condenser Fig. 9. 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 diagrammaticafiy in Fig. 9, 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 very 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 compare- tively low loss of refrigerant and sealed-in lubrication. , ' Fig. 10. Enclosed Type Centrifugal Condensing Unit air conditioning system. This is done because it would not be economical 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, direct- driven centrifugal compressor is illustrated in Fig. 10. . ' . 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 4Q00 rpm for 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 increascrs. Centrifugal systems are particularly well adapted to large capacities (up to 3000 tons) although it is also possible to secure units as low as 50 tons in rating. Because centrif ugal units operate best with refrigerants possessing a high specific volume, and because, of the simplification of lubrication difficulties, they are fre quently used for extremely low temperature applications.. They are adapt able to a wide range of temperatures from --130 F to 50 F. . One important advantage is their flexibility under varying loads, since unite may be de- 816 CHAPTER 36 1952 Guide 'signed 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 ofrefrigeration, 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 principaLdisadvantages 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 Bupply 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 34. . 3. Evaporative 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. The end view of a typical evaporative condenser is shown in Fig. 11. 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 coil, 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 , 817' ;the water-air. mixture^ so as to remove the entrained water. The air leaving the 'unit is almost c6mp^f^yisturate'dts6 that care must be taken in locating discharge ducts to prevent condensation.' , ' ' " ;'. . 1' ' .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 is vaporized by the heat of the refrigerant so that each pound of water usedjextracts approximately lOOO.Btu from the refrigerant, whereas under, standard rating conditions where the water t'emperature rise is 20 F, each pound of water extracts Only 20 Btu from the. refrigerant. Including the water lost by entrainment 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 818 CHAPTER 36 1952 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 Sows 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 Sows. 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 the 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 heaters, consist of a finned coil, propeller fan, and controls suspended directly in the Bpace 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 819 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. Fig. 12. Typical Thekmostatic Expansion Valve 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 ihe'se 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. 12 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 re frigerant. 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 aball float located in either a receiver or the evaporator itself on- 820 CHAPTER 36 1952 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 Valves. 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.js 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 jof 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 tjie 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 directly responsive 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 cutoff 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 systems 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 821 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 are 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 ip a secondary refrigeration system. . ,. '. , Suction Pressure Valves. Suction pressure control valves, frequently called back Jtreasure regulators or two-temperature valves, are sometimes placed in the suction ine 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 mofe 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. Safety 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 case 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 i8 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 warmed to return it to the comfort range. Chapter 38, 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 connect ing piping between the compressor and the condenser requires that a higher pressure be maintained inside the compressor during discharge than in the 822 CHAPTER 36 1952 Guide I "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 nfthe 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 TOO 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 5. 100Table Freon-12 Liquid Lines, Tons Capacity per Ft Equivalent Length Pressure Drop per 100 Ft Equivalent Length, Psi 3 '5 ' 1 . 20 - t OD i OD i IPS |OD i IPS lOD 1 IPS . li OD 11 IPS If OD 11 IPS If OD 2 IPS 21 IPS 3 IPS 31 IPS 4 IPS 0.88 2.89 , 4.88 4.88 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. 2.68 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 pier ton of refrigera tion, great care should be given 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 fpm 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. The total Refrigeration 823 Table 6. `Maximum ^Tons of Compressor. Capacity for Freon-12 Lines . . (Only for temperatures indicated) . : ; ; Line Size, Inches i OD 1I OIPDS | IPS { OD . f IPS li OD 1 IPS 1| OD li IPS li OD ii ips 2i OD 2 IPS 2| OD 2i IPS 3J OD 3 IPS 3| OD 3| IPS 4J OD 4 IPS 5 IPS 6 IPS 8 IPS 10 IPS . 12 IPS ' Suction Lines- ' . Discharge-Lines Based on 105 F Condensing Temperature .. Psi Pressure Drop per 100 Ft Equivalent length at 40 F Saturation Condensing Temperature . i. 0.14 0.17 0.25 0.35 !0.55 0.68 1.26 1.43 1 0.20 0.24 0.35 0.45 0.76 0.94 1.80 2.01 21 0.28 0.34 0.51' 0.65. l.J 1.35 2.57 2.89 i? ... 0.35 0.42 0.62 0.79 '4 M o:'4i 0.49 0.73 0.93 5. 0.45 0.54 0.81 1.03 lift F.; (;F 1.43 1.87 1.15 1.50 1.34 1.65 3.17 3.54 1.58 ; 1.92 3.76 4.17, 1.75 2.12 4.15 4.60 2.97 3.26 5.05 5.29 2.38 2.62 4.05 4.25 2.21 2.70 3.40 4.05 3.12 i 3.82 . 4.78 5.75 4.45 5.37 6.79 8.10 5.50 6.72 8.42 10.12 6.38 7.68 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 19.1 20.9 27.8 30.2 8.60 12.1 10.9 ! 15.3 17.1 24.0 ; ;171 24.0 27.2 38.2 29.4 42.3 39.7 , 55.7 43.2 61.0 15.1 19.2 30.1 30.1 47.8 51.8. 69.8' 76.1 17.4 32.2 34.6 34.6 19.2 24.5 38.2 : 38.2 55.0 60.0 80.3 87.0 ' 60.7 66.2 - 88.7 : 96.0 19.2 20.6 32.2 32.2 51.5 54.5 72.0 78.8 15.3 16.5 25.9 25.9 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 97.3 103 176 322 111 118 203 366 123 130 : 224 403 95.8 101.6 171.5 266 77.1 81.6 137.8 214 211 297 422 523 602 664 461 370 352 503 712 887 1024 1130 725 582 550 780 1108 1373 1582 1748 1041 836 pressure drop in the suction line should be between one and two psi, if the velocity can be kept to within the specified limits. Compressor discharge or'hot gas lines may be designed with velocities from 1000 to 5000 fpm, except for dense gases such as carbon dioxide, where noise considerations will reduce the tipper limit. A pressure dyop 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 ACRMA Equipment Standards-1946, of the Air Con ditioning and Refrigerating Machinery Association, and are used by permis- Table 7. "" Approximate Suction-line Capacity Factors for Equal Pressure ' '. - Drop of Freon-12 . - . .. 20 0 -Saturated Suction Temperature. F. 50 40 30' ib -io -20 Factor ...: .......... 1.09, 1.00 0.92 0.86 0.80 .0:74 0.66 0.56 824 . CHAPTER 36 1952vGuide vsion. Table'5 shows the tonnage capacity normally allowed for'Freon-12 liquid lines per foot equivalent length of pipe, and Table 6 the maxirqum tonnage for suction and discharge Freon-12 lines. Table 7 presents suc tion-line capacity factors for equal pressure drop. "; - ACCESSORIES - Tlehydrators, oil separators, strainers, yibration.eliminatbrs, sight glasses, and various types of valves are accessories frequently needed for the proper Refrigeration 825 in water lines leading to wateh cooled condensers. Sight-glasses, which permit visual inspection of the condition-of the refrigerant are sometimes installed on factory assembled commercial unit systems. It is particularly advisable to place such a fitting before the expansion valve, if the evaporator is located above the condenser. ". r Flexible vibration eliminators, usually consisting, of a 'bellows design covered with woven, copper wire, are sometimes installed in copper lines where units 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 isolate portions :of a system. Fio. 13. 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 into 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 expansion valves, as well as before regulating valves 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. 13 and 14. : From Fig. 13 it may be observed that power requirements for-the centrif ugal compressor increase much more rapidly than for the reciprocating compressor, with increase in evaporator temperature. Similarly, the capacities of the steam ejector and centrifugal compressors increase more rapidly than those of the reciprocating compressor with increase in evapo rator temperature. Thus, both the steam jet and centrifugal machines tend to be more self-regulating than the reciprocating. It" is also evident from Fig.' 13 that the steam jet equipment is best suited for operation at high evaporator temperatures. ' The. effect of condenser temperature upon the power and capacity of the different types of compressors is shown in Fig. 14. It may be noted 826 CHAI P' TER'36 1952 Guide that the powerirequired by :the reciprocating compressor increases rapidly with increase, in condenser -temperature^ while the power curve for the ' centrifugal compressor is relatively flat. It is also evident that the ca-: parity of the steam.jet compressor is independent of condenser temperature until a certain point is reached, where it .drops to- zero. As previously stated, steam jet equipment requires more condensing water than other types of compression systems. Consequently, steam jet systems are well suited to t^iose 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 Hajobitt Used ' ' Some Used Few Used 0 to 5 Unit systems in con Unit central systems Built up central sys ditioned space. . using duct distri tems. bution. 5 to 25 Built up central sys Unit central systems tems using recipro .. using duct districating compres-. : bution. . . sors. : Unit systems in con ditioned space. Built up systems us ing absorption and adsorption sys tems. 25 to 50 Built up central sys tems using recipro cating compres sors. Built up central sys. terns using centrif ugal compressors. Central systems us ing adsorption sys tems. 50 to 400 Built up central sys tems using recipro cating. compres 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- terns using steam vigal compressors. jet'. job is of utmost importance for satisfactory results. The most important factors in the selection of the equipment are: 1. Loads (as determined by the conditions of the space to be cooled), . 2. Economics (both initial and operating costs). . 3. Codes (local safety codes must be adhered to and influence the type of system to be used). .. . .. ' . -1 A btoad division of equipment to be used for a particular installation or application maybe made on the basis of the magnitude of the load. Gurrent'-general practice is outlined in Table 8. . Unit"or 'packaged., systems, consisting of a reciprocating compressor, condenser, evaporator, and fans,, are generally used in the smaller sized jobs where electric power is available, as they are manufactured complete, ready to install, and are the most economical (see Chapter 25). . The reciprocating, compressor in the built-up central system (see c Refrigeration 827 .' Chapter 29) covers the widest rarige 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. 13 that all systems using compressors have a common characteristic, namely, that the capacity varies. with the evaporating temperature. Not only can the equipment be selected to produce a given result, but the performance can be predicted under 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 - in 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. 15. 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 is plotted on the same graph. The operating point will be, of course, where the two curves cross. Data given in Table 9 illustrate two types of conditioned enclosures having 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 82 percent sensible to total heat, the operating point A in Fig. 15 is found to be 42.2 F evaporating temperature, with a face velocity of 500 fpm. In the case of the restaurant, with a ratio of 69.5 percent sensible to total heat, the air velocity is lowered to 300 fpm, and the evaporating tempera- 828 . CHAPTER 36 1952 Guide * Table'9. Typical Operating. Conditions for Two Types, of Load . Type o Enclosure Load, Bttj peb Hour Sensible Latent Total Ratio Sen* BIBLE TO Total Air Entering Con. _ F Deg Per Cent RJH. Operating Balance Point Evapo rator Temp F Deg Con denser Per Cent Pressure Sensible . Lb per Heat Sqln. Restaurant. . 103,000 45,000 148,000 0J695 82 45 .34.4 123 .69.9 Office.................. 121,000 27,000 148,000 0.820 82 45* 42.2 100 82.1 ture is lowered to 34.4 F as shown in point B of Fig. 15. In order to obtain the same capacity, a larger condensing unit is used. This illustration assumes zero pressure drop through the suction line. The pressure drop can be taken into account by shifting the compressor performance curves by the amount of pressure drop expressed in Fahrenheit degrees. REFERENCES 1 Air Cycle:Refrigeration, by Paul C. Scofield (Refrigerating Engineering, Vol. 57, No. 6, June 1949, pi 558). * Application and Economy of Steam Jet Refrigeration to Air Conditioning, by A. R.Mumford and A. A. Markson (A.S.H.V.E. Transactions, Vol. 44,1938, p. 33). *A New Development in Absorption Refrigeration, by'A. A. Berestneff (Re frigerating Engineering, Vol. 57, No. 6, June 1949, p. 553). .. 4 The Application of Storage Refrigeration to Air Conditioning, by C. F. Boester (A.S.H.V.E. Transactions, Vol. 45, 1939, p. 675). `. 5 Use of Cold Accumulators fn the Air Conditioning Field, by R. W. Evans and C. J. Otterholm (A.S.H.V.E. Transactions, Vol. 48, 1942, p. 123). BIBLIOGRAPHY A. Refrigerating Data Book, Vol. 1 (American Society of Refrigerating Engineers). B. Refrigeration Engineering, by H. J. Macintire (John Wiley & Sons). C. Theory of Mechanical Refrigeration, by N. R. Sparks (McGraw-Hill Book Co.). D. Refrigeration and Air Conditioning Engineering, by B. F. Raber and F. W. Hutchinson (John Wiley & Sons, 1945). E. Refrigeration, by J. A. Moyer and R. U. Fittz (McGraw-Hill Book Co.). : F. Refrigerants and Absorbents, by W. R. Hainsworth (Refrigerating Engineering, August and September, 1944). ' G. Air Conditioning and Refrigeration, by B. H. Jennings and S. R. Lewis (In ternational Textbook Company, 1944). . - H. Refrigeration and Air Conditioning, by Jordan and Priester (Prentice-Hall, Inc., 1948). . . ' -A ' i CHAPTER 37 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. Dehumidification may be accom plished by latent heat removal, together with sensible heat removal, as described in Chapters 29, 34, and 35, 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, silica 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, during the 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. ADSORBENTS 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 829 830 CHAPTER 37 1952 Guide i- the result that water is extracted by the adsorbent and its weight increased, while the moisture content of the gas . is correspondingly reduced. (The adsorbent is said to be saturated for a given condition when equilibrium is attained.) The weight of water a given adsorbent will extract is dependent upon the relative humidity. (ratio of the partial pressure in the gas to. the saturation pressure at a given'temperature) and the temperature of the adsorbent. The process is reversible; if the temperature of the adsorbent is raised until the vapor pressure of the adsorbed water becomes greater than the partial pressure of the vapor in the surrounding atmosphere, water will be released by the adsorbent. After the adsorbent, cools to room tem 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 sorbent so that it may be used repeatedly. ' 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. . 7. Be available at reasonable.cost. 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 pre cipitate is converted into a highly porous adsorptive material. It is low 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 elements indicated spectrographically. Substantially all of the soda is combined 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. water. High resistance to shock and abrasion is one of its more important physi cal characteristics. Commercial sires range from a powder passing through 300 mesh screen to particles 1 in. in diameter. The sizes commonly used are 8-14 mesh and $ in. to 8 mesh. The average weight for most forms is & I f f; i Dehumidification by Sorbent Materials 831 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 thie 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 sire . 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 AWt, Fe/h, Si02, TiOi, and HtO 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 adrerbent properties, but details concerning them are not available. . DEHUMIDIFICATION BY SOLID ADSORBENTS , Since adsorption is primarily a condensation process, heat, equivalent to the latent heat of evaporation of the vapor, plus the heat of wetting (which is an additional amount of heat, depending upon the vapor being adsorbed and the adsorbent used) is liberated. The sum of the latent heat of evap oration and the heat of wetting is known as the heat of adsorption. During adsorption it might be said that latent heat is transformed into sensible heat, which is dissipated into the adsorbent, into the metal of the adsorbent container, and into the gas mixture, resulting in a rise in temperature. Fig. 1 shows the relationship between temperature, vapor pressure, and moisture content of a solid adsorbent. These curves indicate the general performance of solid adsorbents, although the exact values vary for the 832 CHAPTER 37 1952 Guide different adsorbents, and may. vary even for different types of the same compound. The effects of vhpor pressure and temperature upon the mois ture content of an adsorbent may be observed by referring to Fig. i. 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 , awater. vapor pressure of 13.2 mm Hg, the water content of the adsorbent is 33 percent. . . With ah 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 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 tem perature of 70 F, the moisture' content of the adsorbent is. 20 percent, while at 100 F, the equilibrium water content is 11 percent. . .. , .. In practice, the temperature rise in the dehumidified air caused by the adsorption heat, is approximately 10 deg F for each grain of moisture re 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 ap 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 833. 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 hilmidistat 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 the 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 at 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 occupied 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 huinidity is important, dehumidification is used to advantage . in conjunction with cooling. 834 CHAPTER 37 1952 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 pre- sure. Calcium chloride is frequently used because of low cost. ' Liquid Absorbents: These are primarily water solutions of 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 or 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 moisture 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 means 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. These 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 huinidity of 70 percent, i.e., having a dew-point of 60 F, or a water vapor pressure of 13.2 mm Hg, the water Dehumidification by Sorbent Materials 835 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) Fig. 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 concentrator, a solution heater and a cooling coil, all as shown in Fig. 5. The contactor and cooling coil are located in the wet air stream. The air to be conditioned is brought into contact with an aqueous brine solution having a vapor pressure below that of the entering air, resulting in a trans fer of moisture from the air to the brine solution. This results in a conver sion of latent heat to sensible heat, which raises the solution temperature and consequently, the air temperature. The temperature change of the' 836 CHAPTER 37 1952 Guide 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 Cooling coil and. Fig. 5. Liquid Absorbent Equipment in Which Solution Cooler . and Contractor are Combined .. of the absorption process. During concentration, the aqueous vapor pres sure of the solution is greater than that of the surrounding air/ while during dehumidification, the reverse is the case. Utilization of this principle per mits winter humidification by heating (instead of cooling) the solution pumped to the contactor. ' Water is thereby evaporated into, instead of being condensed out of, the conditioned air stream. This requires dilution of the'brine;externally to the contactor, rather than concentration. . > 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 practice, when maintaining a low humidity ratio, to recirculate a large percentage of the air in the room through the dehumidifier, and to add only enough out side. air to meet the needs of the problem. The humidity ratio of the mixture of outside and recirculated air and the dehumidifier performance data can be used to calculate the humidity ratio of the air leaving the de humidifier. The difference between the humidity ratio of the air in the room and that of the dehumidified air entering the room represents the Dehumidification by Sorbent Materials 837 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 (118.4 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 = . Grains per ` Minute 120 1800 grains per person per hour is obtained from Fig. 7, Chapter 6, by interpolation between curves C and D. , - 2. From burned gas: ' 15 X 650/60 =; ' 162 1 cu ft natural gas produces approximately 650 grains of , moisture. ;. 3. From exposed water surface: 2 X 20 =- 40 Evaporation from water surface is assumed to be 20 grains per (minute) (square foot) at 87 F water with air movement of 100 fpm. . > . .4. From infiltration:.,, gx X (118.4 -- 24.1) = oO x Id.00 . . . .696. ; One air change, 6000 cu ft, assumed per hour (see Chapter 10). . . 5. Moisture transmitted through room surface: . ,. : ' ~ X 3 X (0.783 - 0.176) = 67 Permeability assumed to be 3 grains per (square foot) ' (hour) (inch Hg vapor pressure difference on two sides of . : . , .. .. . wall). ; Total moisture gain from internal sources 1085 . Let q be the air delivered to the room, pounds per minute.] Let it be assumed for this problem that 85 percent of the air is recirculated and 15.percent is outside air. Enough air must be supplied to replace leakage from the system,or to satisfy normal ventilating requirements.for the occupants of the room as'given in Chapter 6, which* ever is greater. The amount is estimated from experience or obtained by test. : The humidity ratio of the mixture of recirculated and outside air entering the dehumidifier is then: . .. 0.85g(24'l) U.oog + 0.15g _ gg g grains per pound entering dehumidifier. ' For the dehumidifier whose performance is shown in Fig. 6, for 38.3 grains per pound in entering air, the leaving humidity ratio will be 6.5 grains per pound. . Effective dehumidification in the room is 24.1 -- 6.5 or 17.6 grains per pound of supply air. 838 . CHAPTER 37 . , - . 1952 Guide Fio. 6. Performance Data fob Typical Commercial Solid Adsorbent ' Dehcmidifier . ' 1085 grains per minute . . . .. , Then q = 17-6~ g|:ait{8 per pound = 616 " air Per minute minimum that must be supplied to the room to maintain 30 F dew-point. . Note that this figure represents the minimum requirement for the arbitrary condi 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 to force moisture through the walls into the dehumidified zone of relatively low vapor pressure. As this'process can: be an unnecessary load on-the dehumidifyirig equipment, provisions should be made for keeping the vapor transfer to a minimum. Also, if the space is cooled below the ambient dew-point, there is a possibility that condensation may occur within the walls, unless vapor 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 wiil be protected from rupture. (See section on Water Vapor and Condensation, Chapter 9.) CHAPTER 38 Automatic control Basic Types of Control, Types of Controllers, Actuating Devices, Actuated Controls, Residential Control Systems, Zone Control, Automatic Control Application, Control for Central Fan Systems, District Heating Control, Panel Heating Control, Indicating and Recording Equipment THE function of atUomatic control, as applied to the heating, ventilat ing and air conditioning industry, may be broadly subdivided into the maintenance of temperature, humidity, and pressure, within predetermined ranges. It automatically coordinates the operation of the various con trolled devices in proper sequence to produce the desired result. BASIC TYPES OF CONTROL Available automatic control equipment may be divided into four main groups depending on the primary source of power: 1. A self-actuated regulator is one in which all the energy necessary to operate a valve or damper motor is supplied by the responsive element.or bulb. Temperature changes at the bulb result in pressure changes of an enclosed fluid which transmits them directly, to the valve or damper motor. Instruments of this type are available either with a rigid bulb or with flexible tubing from the bulb to the operating motor. The flexible tubing ihay 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 ho operate motors, relays, or other con trolled items. ' 1 Electrical controls may be divided into two classes: (1) those wherein the primary measuring device utilizes contacts to regulate the flow of the electric current, and (2) those wherein the primary measuring device is a resistance wire component of. an electronic circuit; these are known as electronic controls. ' : 3. In pneumatically operated equipment the primary source of energy is compressed air 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. power is a suitable liquid at a pressure of 15 to 25 psig or higher, which is handled in the same manner as compressed air. . . TYPES OF CONTROLLERS The basic types of controllers and their operations are: . 1. Two-position or on-off controllers are the simplest type and are clearly described by the name. With controllers of this type the valve or damper motor.can assume only two positions, either open or shut. . 2. Proportional or gradual acting controllers function to re-position the controlled device, by small increments of travel, to regulate the flow as the controller senses a slight change in the controller condition. 3. Floating controllers act to produce valve or damper movement whenever there is a deviation from the control point. Whenever the condition to be controlled is above the control point, the valve closes at a constant rate, and continues to close until the temperature returns to the control point. Below the control point the valve reverses its action and moves in the other direction until the control point is again reached. 4. Automatic reset (or proportional plus reset) controllers function to reposition a valve or damper by small increments of travel, as in a proportioning controller. In addition, a mechanical device in the controller automatically and constantly resets the instrument to offset the normal drift (inherent in a proportional controller) be .. 839 . .. 840 CHAPTER 38 1952 Guide tween maximum and minimum load. The rate of reset is manually adjustable and must be set to meet the load requirements of the individual system. Controllers may also be designated by types as: a non-indicating con troller, 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 and 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 duct work. 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) 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 could open a volume damper on a rise in temperature in summer, and close the same damper on a rise in temperature in winter: 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 a 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 the pipe line 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 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 differential type which maintains a predetermined difference between two pressures. For pressures in duct work, static pressure regulators are available in the differential type. They are sensitive to changes of 1/100 in. of water. Automatic Control 841 , 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 a motor operator, as directed by a thermostat or other controlling device. 1. A normally open or direct acting valve will assume an open position when all operating power is removed. ' 2. A normally closed or reverse acting valve will assume a closed position when all operating power is removed. 3. Single sealed valves are designed for tight shut-off using appropriate disc ma terials for various pressure ranges. . 4. Pilot piston valves serve a similar function on high pressure installations. 5. Double seated or balanced valves are designed for applications where tight shut off is not required. They are not affected bv varying inlet pressures or pressure differentials, and thus are widely used where these conditions exist. 6. A three-way valve is fitted with a double faced disc, operating between two Sorts, and functioning to close one port as the other is opened. Depending upon ow it is installed, it may be used as: a. A three-way mixing valve to mix as required two fluids entering the two inlet ports and leaving through the common outlet port. b. A three-way diverting valve to divert the flow from the inlet port to either of the outlet ports. .. Valve discs, poppets, and seats are available in various shapes to meet any desired flow characteristics with various materials as required by serv ice conditions. A damper is designed to control the flow of air or gases, and is similar to a valve in this respect. Single blade dampers are generally restricted in size because of the difficulty of securing proper operation with high velocity 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 and flow characteristics than the parallel blade type. For long life and trouble free operation, dampers should be constructed with heavy metal frames, blades of iron adequately braced, and ample bearing surfaces of non-corrosive materials. When fairly tight closing is desired, felt may be glued and riveted on the edges and ends of the blades. Other materials for blades and frames are also used for special services. A damper motor 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 one or more damper blades. Suitable brackets are available for floor, wall, or duct mounting of the motor. 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 motor. Various types of relays are designated as follows: 1. An electro-pneumatic relay, when electrically energized, starts 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- 842 CHAPTER 38 1952 Guide -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 a valve or damper motor lever and is affected by both valve or damper position and controller demand. It is re positioned by a thermostat or other controlling device, and is arranged to give a definite motor position for a given force from the thermostat without regard for.motor hysteresis, friction, or pressure variations of the controlled fluid. 6. An electronic amplifier is used only in electronic control circuits to amplify the micro-currents of electronic controllers to usable voltages required by standard electric actuating devices. They may be either two-position or proportioning re lays. 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 control medium failure. Manual switches are available in the two-position or proportional types. Two-position switches change the flow of energy from one line to one or more other lines; 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. 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, and also economy of operation. 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 check 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 check the fire whenever a prede termined temperature or pressure has been exceeded. A manually operated base ment switch is usually included on the motor so that the draft may be opened and the check closed when the boiler or furnace is being filled with coal'. 2. Cool Fired Stokers. Domestic stokers are usually controlled by a room 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 to its maximum rate. When the thermostat is satisfied, the relay provides for a minimum flow of fuel and air to the burner to maintain the fire at its minimum rate. The limit control prevents the continuance 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. Automatic ignition usually is not available and the firing of a stoker is normally on or off. 3. Automatic Oil Burners. Automatic oil burner controls normally consist of a room 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 or 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 Automatic Control 843 sqpply to be shut off. If. the. oil and air mixture ignites properly, the buerner con . tinues to run until the thermostat is satisfied, or until the limit control affected by the temperature or pressure in the boiler or furnace stops the burner. 4. Automatic Gas-Burners. The controls for an automatic gas burner usually in clude a room thermostat, a limit control, a safety pilot, gas pressure regulator and a gas valve (solenoid, motorized or diaphragm type). Upon a demand for heat at the thermostat, the gas valve is opened; admitting gas to the burner. The safety pilot ignites the gas which continues to burn until the thermostat is satisfied, or until the limit control shuts off the gas valve. The limit control may also reduce (throttle) the gas flame as required to maintain a desired temperature or pressure of the heating medium. If the pilot flame is extinguished for any reason, either before or after the main gas valve is turned on, the safety pilot closes the gas valve, thus eliminating the danger of delivering gas to the burner without ignition. 5. Electric Heating. Electric heating has become popular in.those areas where electric power is plentiful and inexpensive. The electric heating elements may be located in each individual room and turned on and off by thermostats in each room, or the heat may be supplied by a central heating system. In the case of a central heating system, the control is usually of the proportioning type which ener gizes from five to ten heating elements in sequence, according to the demand for heat, by means of a sequence controller consisting of a series of switches operated by 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 control, having bellows responsive to the boiler pressure, which breaks 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 source of heat 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 valves, damper motors, stokers, oil burners, gas burners, etc. Room thermostats may be of the plain or single temperature type, or of the day-night type providing for automatic night lowering and morning increase of the control point. 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 thermostatically controlled systems, a possible fuel saving of from 7 to 10 percent may be obtained by 844 CHAPTER 38 1952 Guide reducing the house temperature 6 to 10 deg from about 10:00 pan. to 5:30 a.m.* , 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. . 2. It should never be mounted on an outside wall or other cold surface, or where it is exposed to cold drafts from an outside door. 3. It should never be mounted where it will be affected by direct rays of the sun; by heat from a nearby warm surface such as chimneys, pipes or ducts in a wall, or 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. ' 5. It should be located where it is safe 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. . System Control There are several types of system control in common use for residential applications. They are usually of the two-position (on-off) type, or of the proportioning type. .1. Two-Position (On-Off) Control. The most simple type of domestic control is the type in which the room thermostat starts the burner or other source of heat when the temperature of the air at the thermostat falls below, the thermostat setting, and 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. 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 water system may be run 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. Air-Conditioning Systems Year 'round residential air-conditioning systems which provide for heat ing 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 described later in this chapter, since the basic principles are the same and the final results must provide for the comfort of the occupants. Economy in first cost may result in both lack of economical operation and discomfort. 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. Save Fuel for Victory, University of Illinois, Engineering .Experiment Station Circular Series -No. 47, p. 31. Automatic Control 845 3. Service section such as kitchen, pantry, servant's quarters. 4. Recreational areas. Zone control for steam and hot water heating systems is employed where it is desired to control the heating effect of ,a multiplicity of radiators or convectors, located in various heated spaces, through the use of a single regulator. Under certain conditions, particularly in buildings of limited size, it is possible to consider the entire building as a single heating zone. In such cases, the zone regulator, or master controller, may operate, directly, the automatic firing equipment of the boiler or the reducing valve in the street steam main. In large buildings the demands of satisfactory tempera ture control, however, will make it necessary to sub-divide the heating system into suitable zones. ' 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. 1. Exposure may be a factor to be considered, with particular reference to pre 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 sub-dividing of 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 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 otherwise desirable, often will influence the decision as to the final number of zones 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 possibly should be sub-divided vertically into two or more zones, for the higher structures. Also, the presence of two or more wings, having the same generaTex posure, may suggest the desirability of more restrictive zoning. In smaller build ings, and in those of larger extent where cost and other conditions limit the number of zones, a common compromise is to combine the North and West exposures in one zone; and the East and South exposures in a second zone. Frequently, when the street floor level is given over to public spaces or to activities which are markedly different from, those carried on in the remainder of the building, it.is advisable to provide a separate steam main, with conventional room thermostats in each individ ual area. . For steam heating systems, the radiator output may be varied pro . portionately to the changes in outdoor temperature, by any of a number of general methods. Those in most common use are: ' 1. Turning the steam on and off at appropriate intervals, as dictated by tempera ture or time considerations, proportioned to the need for heating. 2. Varying the pressure of steam in the system in accordance with the demand for heat. . 3. Throttling the steam pressure, at the demand of the controller, to allow flow through orifices in proportion to the heating requirements. In hot water heating, the accepted practice is (1) to vary the tempera ture of the hot water supplied to the system, or (2) to vary the flow of hot water; both being varied proportionately to the heating requirements. The regulator, for each zone usually is of a type which in some manner responds to the outdoor temperature and effect of sun and wind for the 846 CHAPTER 38 1952 Guide I' zone. Many of the available zone controllers are arranged in such a way as to be affected also by the temperature of the heating system and the in door temperature in the zone. Whatever the mechanical features of the regulator, its function is to dictate the flow impulse, or'rate of flow, in such a way as to maintain the-desired indoor temperature in the zone, regardless of the fluctuations in the outdoor temperature! Provisions also inay be made to maintain a predetermined low economy temperature in each zone during periods of non-occupancy; to facilitate quick warming-up following such periods; and to follow those portions of the daily cycle of control with normal heating effect during the occupancy period. A control panel, at a central location, may be arranged so that manual switches for each zone may raise or lower the operating temperature. Time switches, if desired, may be provided for obtaining, automatically, any day-night or other predetermined control program which the operators of the building may desire. The characteristics of the regulators which are 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 firing means, are some of the more com mon regulators, which are used to control the flow of steam or hot water, under the command of zone controllers. The characteristics of these regulators usually are determined by the manufacturer of the type of con troller which is selected. . AUTOMATIC CONTROL APPLICATION Some of the considerations affecting the selection of automatic controls for applications are given in the following paragraphs which describe con trols and operation for various types of units. Unit Heater Control Two-position (on-off) control by means of a room thermostat is the standard method of control for unit heaters. A limit control should be incorporated to prevent operation of the unit heater fan motor when steam or hot water is not available. The limit control can be a surface thermostat or pressure control. Where there is no possibility of drafts, and continuous air circulation is required, the unit heater fan motor may operate continuously. In this case, a room thermostat controls a valve (two-position or proportioning) in the stream or hot water supply line. Unit Ventilator Control Various makes of unit ventilators are designed for different control cycles Selection of automatic temperature control for unit ventilators is largely determined by the design of the particular unit. The choice of control cycle may also be determined by local and state ventilating codes, particularly where units are installed in school rooms. It is desirable to coordinate the selection of control cycle with the unit ventilator manu facturer since, in many cases, modifications of the unit are required for the installation of the control equipment; and, in some cases, it is desirable to have the equipment factory-mounted. Two typical control cycles are: (1) Variable Outdoor Air with Fixed Minimum, and (2) Variable Outdoor Air without Fixed Minimum. Control Cycle No. 1. In full heating position, the outdoor air damper is closed, the recirculating air damper is open, and the supply valve is open." In full cooling position the outdoor air damper is open, the recirculating air damper Automatic Control 847 is'closed, and the supply valve is closed or at a minimum position to maintain a minimum discharge air temperature. The sequence of control operations is: On call for cooling, under control of a room thermostat, outdoor air damper opens to minimum setting. The supply valve then closes gradually, after which the outdoor air damper gradually opens to the maximum position and, simultaneously, the re circulating air damper closes. A low limit thermostat mounted above the coil prevents the discharge temperature from dropping below, a predetermined minimum. Control Cycle No. 2.. In full heating position the outdoor air damper is closed, the recirculating air damper is.open and the supply valve is open. In full cooling position the supply valve is closed, the outdoor air damper is open and recirculating air damper is closed or at any position required to maintain a minimum discharge air temperature. The sequence of control operations is: On call for cooling, under control of a room thermostat, the valve gradually closes. As the valve leaves full-open position, control of the recirculated air and outdoor air dampers is transferred to a thermostat installed ahead of the heating coil to main tain a minimum air temperature. On continued call for cooling, the valve gradually closes If direct radiation is used, it is desirable that it be controlled in sequence with whatever control cycle is adapted for the unit ventilators. . 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 selfcontained, 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 ing paragraphs. Well Water. Where well water is used directly in air washers or cooling coils, control of temperature or humidity is usually 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 control, 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 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 volume. 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 thermostat 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 off 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. 848 CHAPTER 38 1952 Guide - Steam Jet. A steam jet refrigeration system is commonly controlled by means of a thermostat in the chilled (secondary) water. The thermostat operates a two- position valve in the steam line to the jet. In the case of multiple jet units, program or step control can be achieved by controlling the jets in sequence. As in the case of direct expansion refrigeration units, a system of control is advisable for. the water- cooled-condensing unit. ..... . Centrifugal Units. The control of centrifugal refrigeration units or other types of vacuum systems is customarily achieved by means of a thermostat in the ctulled water to control the operating cycle of the equipment at full or reduced capacity. Adsorption Units. Control of adsorption units consists of a damper control which, in response to humidity, controls the 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. , 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 addition of a hygrostat or wet-bulb controller controlling the water valve from space conditions. In order to secure a constant discharge dry-bulb temperature, a coil is provided with proportioning valve controlled by a proportioning thermo stat in the unit discharge. - - CONTROL FOR CENTRAL FAN SYSTEMS Automatic temperature control for central fan heating, cooling, ventilat ing, and air conditioning systems involves the proper application of various types of controlling instruments and associated regulators such as valves, dampers, and damper operators, relays and other auxiliary equipment 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. Otherwise, some arrangement of available package equipment probably would be used. It is impossible to state in detail the control ap paratus 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. Ventilating 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 considerations to be borne in mind: (1) to control space temperature; (2) to prevent drafts; (3) to guard against freezing. Automatic Control 849 Usually in central fan systems, suitable thermostats operate valves in the steam or hot water supply to heating coils, or 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 preheaters and reheaters, a duct thermostat (following the preheaters, and located in the entrance to the chamber between the groups of coils) controls the pre..heaters: 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 mtake to controf 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 con trolling 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 con trol, in conjunction with a thermostat in the heated space or in the return air. TO Fig. 1. Control Diagram fob Year .'Round Air Conditioning System 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 changed as the humidity in the conditioned space varies. 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 typos 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. . 4. Cooling and dehumidifying may be controlled by means of thermostats, and hygrostats 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, mich controlling instruments normally are located in the fan 850 CHAPTER 38 1952 Guide - discharge 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 is associated, a room thermostat in each zone may operate, mixing dampers iri the inlet to each zone duct, determining the quantity of warm air which-is required from that 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 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 'round 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 starter, 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. . - THERMOSTAT HYGROSTAT . DISTRIBUTION System Using 100 Percent Outdoor Air 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 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. 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. Automatic Control 851 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 Fig. 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. 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. DISTRICT HEATING CONTROL There are three general means of obtaining centralized control of heat output of radiators in district heating systems. 1. Controlling the rate of steam-flow into the radiators. 'This is accomplished by equipping the radiator inlets with orifices, and controlling the flow of steam through them into the radiator by controlling the difference in pressure between the supply and return. . 2. Controlling the temperature of steam in the radiators by varying its pressure'. This involves the use of high vacuums to obtain low steam temperatures. This must be supplemented by some other type of control for low heat output. 3. Controlling the length of time steam flows into the radiators by admitting steam to a heating system intermittently and varying the length of the on and off 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 outdoors. (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 radiator 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 put in good operating condi tion. In general, the heating system in a building is not given the atten tion that other mechanical equipment is given, because .it will continue to function, after a fashion, even though changes in piping, location of radiation, settlement of piping, and the normal wear and tear or other changes have taken place. Because of this depreciation of the system, operation becomes more and more costly, and parts of the building have to be greatly over heated in order to prevent underheating in other parts. Vents, traps, vacuum pumps, and valves should be given a careful inspection and re placed 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 and properly vented. These inspections and repairs are not costly, and may prevent a much greater outlay in future years. In most cities district heating companies will .be willing to make a survey of heating systems, and offer recommendations in regard to operation and 852 CHAPTER 38 : 1952 Guide/ .changes in piping layout.. The selection of control equipment'depends upon the type and size of building, and the degree of . saving which may be obtainable. PANEL HEATING CONTROL Automatic controls for radiant and convective heating differ somewhat due to the thermal inertia characteristics of the panel heating surface, and theincrease in the mean radiant temperature within the space under in creasing loads for panel heating. ` 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 Automatic Control 853 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 Jag 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' ' ' ELECTRONIC ' FLO* TEMft ' Fig. 3. Panel Heating Control System supply of heating medium. This will cause uncomfortably. Warm condi tions to' exist in a space. Also, there will be a considerable . delay between the tiine the thermostat calls for heat and the time heat is actually de livered t6 the space (because of the large part of the heat that must first be stored in the thermally heavy radiant surface). Whenever inertia exists in the source of heat supply, uncomfortable cycling of space conditions will result unless means of anticipating load changes before they occur in the space, or means of setting the basic energy supply fate from load conditions, are provided. . If a thermally heavy radiant surface is used, the primary control should 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 ' Fig. 4. Electronic Control System fob Panel Heating 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. ' . Two of the many methods used to achieve satisfactory control are shown in Figs. 3 and 4. Fig. 3 shows a control system operated by an outside thermostat in conjunction with a room heat control instrument. The outside thermostat modulates the temperature of the circulating water in the coils by mixing some of the hot water leaving the boiler with a proportionate amount of return water which is diverted to the three-way valve'. . One type of room instrument consists of a blackened copper sphere of 6 or 8 in. in diameter, in which a cylindrical sump contains a volatile liquid. A small electric heating coil creates in the sphere a vapor pressure which remains constant as long as the total heat loss from the sphere is at the desired rate. If the Operative Temperature becomes too high for comfort, a greater vapor pressure results from the smaller heat loss from the sphere. This acts on a diaphragm and reduces the supply of heat to the room. With too low an Operative Temperature, the reverse action occurs. A similar instrument, which has an electric heating element for warming the air inside 854 CHAPTER 38 1952 Guide the sphere and the thermostat-operated switch, is also used for controlling room conditions. ' ' . Fig. 4 shows a typical electronic control system. 'The electronic control system operates the circulator in cycles. ' It varies the flow of water to the panel in proportion to the heat demand, as measured from room, out door, and panel conditions. A low limit immersion thermostat-, set to maintain desired water temperature in the boiler, starts the burner. A high limit immersion thermostat is set to stop the burner at maximum desired boiler water temperature. A manual by-pass, as shown, is desirable to prevent the flow of water into the panel at temperatures in excess of design 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 and a conventional fixed control point room thermostat may be used. If a large infiltration load exists, or 5 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 temperature control is not recommended with heavy panels, though it may be satisfactory with light panels. 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 C02, 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 of recorded, and in other cases, separate instruments are used for the purpose. ' CHAPTER 39 MOTORS AND MOTOR CONTROLS 9 Fundamentals of Motor Selection; Alternating Current Motors, Types and Control Equipment; Motor Rating; Functions of Motor Control Equipment; Glossary of Motor Terms, Enclosures, Speed Classification and Mounting THE electric motor, available in many different types 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-c 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 horsepower design limits are given in Table 1. Power lines are often given voltage ratings known as nominal system voltages which are numerically slightly different from the standardized motor voltages. 3. Phases. Three-phase power supply is most desirable, but only single phase is offered for most residential and rural districts. . 4. Frequency. Sixty-cycle systems predominate in the United States. In foreign countries, 50-cycle systems are 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 oj Power. Dips in voltage from switching or other line disturbances may 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: (1) 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; (6) frequency of starting. 1. Mechanical Arrangement. Arrangement of the driven .machine usually deter mines whether a horizontal or vertical motor is needed. Horizontal motors are more generally available and less expensive; most grease-lubricated ball-bearing motors will operate in either position. Fractional-horsepower waste-packed sleeve-bearing 855 856 CHAPTER 39 1952 Guide Table 1. Reasonable Hobsepoweb Design Limits fob Standabd Motob Voltages POWEB 8UFPLT Standard Motob Voltage Suggested Minimum Suggested Maximum - Hobsepoweb - Hobsepoweb Alternating 1-phase - - Alternating 3-phase 115 230 110 220 . 440-550 2300 4000 4600 6600 - ' -None - ' , - None ' None .- Nonje ; 60 .. \ 100 250 400 1 15 15 - 200 . 1000 * 6000 7500 8000 None , motors are satisfactory for short periods of...vertical operation where no thrust is involved. , s ' If shaft is lilted for momentary operation, special construction of bearing housings will be required for oil-ring-lubricated sleeve-bearing inotors, 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 heeded, 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. , ' '' Belt Drive. . Diameters and widths of pulleys or sheaves and center distances are factors in determining motor-bearing pressure?, and shaft deflection. Mat belts should hot run at greater speeds than about 5000 fpm.- Application of flat belting to vertical-shaft motors is difficult. * -. . -, Chain Drive. The chain manufacturer 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-qf 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-bearihg* motors \ Table 2. Speed Ranges fob Vabiogs Types of Motobs Poweb Supply Tttb . ,. - Speed Range Single Phase . a-c Brush-shifting repulsion motor Capacitor-motor with tapped winding Multi-epeed capacitor-motor ' '' ` .. ': . 3:1 ' 2:1 2 or 3 fixed speeds Poly phase a-c Multi-epeed squirrel-cage ` Wound-rotor motor , 2-speed wound-rotor motor ' Brush-shifting shunt motor . Brush-shifting series motor '' Squirrel-cage motors with variable frequency supply Motor-Generator Set--D-c Drive Motor Rectifiers--D-c Drive Motor . . 2, 3 or 4 fixed speeds . 2:1 4:1 . 20:1 3:1 Very wide range Very wide range . Very wide range d-c . Shunt-wound standard constant-speed motor with field oontrol - . *D-e motor with armature control Adjustable-speed motor ' . ... ........... ; .. Shunt motor with adjustable voltage supply . .* 2:1 in some cases . . <;,Wde from 2:1 to 6:1 Very wide - - * Speed regulation relatively wide. Unsuitable for some loads. Motors and Motor Controls 857 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 tor 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 for an 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 in determining the type of motor. A torque-speed curve is desirable and sometimes essential. The starting torque or breakaway torque required by the driven machine may be as low as 10 percent, as in the case of medium-sized centrifugal pumps, or as high as 225 to 250 percent of full-load torque, as in the case of a loaded 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 the ac celeration. The approximate time required for acceleration from rest to full speed is: Time in seconds = (rpm) X WRf -s- (IX 308) ' (1) where (rpm) = full-load speed in revolutions per minute. T = average torque available for acceleration, foot-pound. - WRf = inertia of rotating parts, pound-foot square. . If the time to accelerate 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 WR1 must be known, since the pull-in torque required of this motor varies approximately as the square root of the total WR1 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 the motor shaft by multiplying by . [(rpm of rotating member) 4- (rpm of motor)]1 (2) 6. Frequency of Starting. The frequency of starting the driven machine affects the motor and control by increasing their heating, particularly where accelerating 858 CHAPTER 39 1952 Guide , t' Type Table 3. Classification of Motors Speed ,. Full Voltage .. Character istics - Starting Starting Torque Current HP -Range . . Constant Speed Drives Application See Footnotes' (o) to () .. Polyphase a-o J -Squirrel-cage general Constant purpose Design A Normal 1-2.5 High 6-8 times times Squirrel-cage Design Constant Normal 1-2.5 Normal 5-6 times . times Squirrel-cage -Design Constant High 2-2.5 Normal 5-6 . times times Wound rotor Constant or High 1-2.5 Low 1-3 variable .. times times (with second iry control) Synchronous high speed . Exactly con Normal . stant 0.75-1.75 times Normal 5-7 times Synchronous low. . Exactly con Low 0.3-0.4 Low 3-4 speed . stant times times All , Medium Small ' Medium * Small All Medium ' large. Medium Large (a) Fans and (e) centrifugal .. ' * - - pumps and centrifugal compressors (a) Fans and centri fugal pumps - and centrifu gal compres sors (5) Reciprocating pumps (e) and compressors started loaded (a) Hoists . (b) reciprocating ` pumps and - ' compressors (c) and frequent (e) or hard start . (a) Fans and centri fugal pumps and centrifugal compressors (a) Reciprocating compressors ' starting un loaded Two value .capacitor Constant High Normal Small (5) Pumps and com- Permanent split .capacitor Capacitor start . Constant Constant Repulsion Induction Constant .<3 Split phase 0Q - Constant and adjustable Low Moderate High Normal Normal Normal Normal Normal Fractional (a) Fans, Blowers Small Fra<v (a) Fans and pumps tional . Medium . . (a) Fans Small (6) pumps and - compressors Fractional (a) Fans (6) pumps and . - compressors (d) fans--direct . Adjustable Speed Drives Polyphase a-o | Squirrel-cage high slip. Transformer adjustment 8quirrel-cage sepa rate winding or ' regrouped poles Wound rotor Variable Constant multi- speed Variable Normal Normal Normal or high Normal or low High Low (with second iry control) Repulsion ?d Variable High s Capacitor low torque Variable Low 3 tapped winding two speed Capacitor low torque Variable o transformer ad- Low .S GO justment Split phase re grouped poles Constant Normal Normal Normal Low Normal Medium Small (a) Fans All (a) Fans (b) pumps and (e) compressors All (a) Fans (b) centrifugal pumps and - compressors Low and Fractional Fractional (a) Fans, centrifugal pumps (b) compressors (d) Fans, drect Fractional (d) Fans - Fractional (d) Fans a. Drives having medium or low starting torque and inertia (WJ2*) such as fans and centrifugal pumps'or reciprocating pumps and compressors started unloaded. b. Drives having high starting torques, such as reciprocating pumps and compressors started loaded. c. Similar to (a) except where frequent or hard starting (large WR1) requires a higher starting and accel erating torque, d. Fans direct connected, e. Stoker drives. -. Motors and Motor Controls '859 time is prolonged by high WR' 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 said 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 start-induction run single phase motor, for in stance, will cost approximately twice as much 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-Rotor Current of Three-Phase, 60-Cycle Motors at 220 Volts*-b .. ' . HP Design . Design F B, C, AND D HP . Design B,C and D Design F Amperes Amperes Amperes Amperes 1M 2 3 5 7H 10 15 20 25 - 1 24 35 45 60 90 120 150 220 290 365 30 435 40 580 50 725 60 870 75 1085 270 360 450 540 675 100 1450 900 125 1815 1125 150 2170 ` 1350 200 2900 1800 * The locked-rotor current of three-plmse, 60-cycle, constant-speed, induction motors, measured with rated voltage and frequency impressed an|j_with rotor locked, shall not exceed the tabulated values. b Locked-rotor current at other voltages shall be inversely proportional to the voltage. c For 1 hp or less the value is given per hp. ' Polyphase Motors The three types of polyphase motors are: squirrel-cage induction motors, wound rotor induction motors, and synchronous motors. Squirrel-edge motors are specified by NEMA standards providing a variety of speed and torque characteristics. Design A motors provide normal starting torque at starting current in excess of Design B motors, and are suitable for constant speed application to equipment such as fans and blowers. Design B 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 unloaders, and on reciprocating pumps. Design D motors have high slip* and are used with flywheels for widely pulsating loads on equipment such as reciprocating 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. 860 CHAPTER 39 - '* 1952 Guide ; As near rated load as possible. In addition, as shown in Fig. 2, power factor and efficiency are better for higher speed motors. Wound Rotor motors are used for applications requiring high starting torque At low starting current, because a wound rotor motor with its con- trailer 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 motor changes the speed torque characteristics. The motor speed, with , ' 1 . Motors and Motor Controls 861 Synchronous motors are used to drive fans, blowers, pumps, compressors and other applications. . Compressor applications having a- high peak torque require the use of flywheels to smooth out power peaks, and should always be referred to the electrical manufacturer for recommendations. Synchronous motors are provided with built-in damper windings on the rotor and operate during the starting period similarly to - squirrel-cage motors. After the motor is nearly up to speed, field ^excitation is applied and the motor draws into step at synchronous speed. After excitation, is applied, the motor runs at exactly constant speed and will remain at this Fig. 1. Speed Torque Characteristics op Squirrel-Cage Motors 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 to 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 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 plant 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. I T" j ?f . HORSEPOWER RATING Fig. 2. Efficiencies and Power Factors for Squirrel-Cage Induction .. - .Motors; * : , . . speed until a load approaching the, pull-out load is reached, whereupon the motor pulls out of synchronism and stops. .. In applying synchronous motors consideration must be given to the torque the motor can develop on pull-in, that is, at the instant when field excitation is applied. Table 5 shows typical application requirements of synchronous motor drives, listing starting, pull-in, and pull-out torques. 'Multi-Speed motors provide flexibility in . many types of drives. -. 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 or 4 speed. Twospeed induction motors are usually of single winding type, having a 2 to 1- . speed ratio such as 600 rpm and 1200 rpm, or may be double winding. Three-speed induction motors are always two winding, and four-speed 862 CHAPTER 39 1952 Guide motors are usually two winding with a 2 to 1 speed ratio in each winding. Motors can be provided in constant torque varying torque, or constant horsepower ratings. The constant horsepower type of motor is consider ably larger than the constant torque motor, , due to "the fact that the same horsepower must be developed at either reduced speed or high* speed. In selecting two-speed motors for fan, pump, blower, or compressor applications, it is usually found that two winding motors are more expensive than'the single winding type. The control cost for two-speed, two wind ing motors, however, is more economical, and therefore the combined price of both motor and control for the two winding motor is only slightly higher.. Because of the improved performance of the two winding motors, and because of the factor of safety provided by two independent windings, the increased cost is frequently worth the difference. Table 5. Typical Application Requirements op Synchronous Motor Drives Showing Starting, Pull-In and Pull-Out Torques Application Method op Connecting Motor to Load Starting Conditions Tobques Start Pull Pull ing - in Out Remarks 3gj Exhaust and venti Coupled or belted lating Usually loaded 50 60-125 150 WR* of fan must be considered Cycloidal positive Coupled or engine Unloaded a type 40-60 40-60 150 Two-speed motors sometimes used - 1 Blowing engines re Engine type ciprocating Unloaded . 40 CQ Turbo high speed Direct connected or Unloaded (in 30 step up gear take closed) 40-60 150 50 150 WK* of blower must be considered Air Engine type Unloaded 40 30 150 Flywheel effect im portant e s i Ammonia and am monia booster High speed--belted Low speed--engine type occasionally coupled Unloaded (by by-pass) 40 30 150 Flywheel effect im portant o O Freon High speed--belted Unloaded (by 45 Low speed--engine by-pass) 50 150 Flywheel effect im portant Gas reciprocating High speed--belted Unloaded (by 40 Low speed--engine by-pass) 30 150 Flywheel effect im portant yH t. if; ,V Single Phase Motors . Single phase induction motors have auxiliary windings or devices for starting, and are classified by the method used. . ' Capacitor start motors develop high starting torque in fractional horse power ratings, and moderate starting torque in larger ratings. They are used for constant speed drive such as fans, blowers and centrifugal pumps. During the starting period, a winding with a capacitor in series is connected to the motor circuit and when the motor comes up to speed, a centrifugal switch cuts the capacitor and second winding out of the circuit. Two-value capacitor motors develop high starting torque employing a starting capacitor and a running capacitor. The starting capacitor gives high starting ability, but is suited for short time operation only, and is cut put for the running condition by a centrifugal switch. The running ca pacitor gives high efficiency at full speed. These motors are used on Motors and Motor Controls 863 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- o^ 1 1 1 1 1 1 1 1 .1 /R pulsion-start induction run 5 5 ^Vf -/> r Wo*1 X ftJOT OR STAI TIN6 WINDING REPIJLS ON START IN CTION RUN ftj<>TO y \,h\ z\\ s -SWITCH OPERATING SPEEDS *s /. & o yo< ' rVJr 'y 5 .& Jf / <7 f A1 f' 9-/. 5# ifs DS : s \ r t if o 3* w % ts\ 4 PER CENT OP PUU. LOAD TORttUE Fig. 3. Speed-Torque Characteristics op Single Phase Motors 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 high break away torque, and where commutator and brush noise are not factora. Split Phase motors have a high resistance auxiliary winding which is in 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, 864 CHAPTER 39 . 1952 Guide ' and when equipped with a high slip rotor, may be used'for adjustable varying speeds through line voltage control. The motors are ideally suited for fan duty. . . Speed-torque characteristics of single phase motors are shown in Fig. 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-EEI-NEMA* recommended three application rules taking into account the greater annoyances re suiting from frequent motor starting during lighting hours against infre- Table 6. Recommended Single Phase Motoe Ratings fob Full Voltage Starting HP Rating Lockbd-Rotor Cubsent at 25 C Amperes General Use (Rules 1 A 2) Special Conditions (with Utility Pshaobsion) (Rule 3) Ho H H H H H 1 1H 2 3 5 115 V 222000 23 31 45 61 70 230V 111000 11.5 15.5 22.5 30.5 . 35 40 50 17000 115 V A-M A-M A-M ' A-M M M 230 V A-M A-M A-M . A-M . A-M A-M M M M M 115 V A-M A-M A-M A-M A-M A-M A-M A-M 230 V 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 same as the NEMA standard for single-phase Design M motors. - 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 frequentlystarted) 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 withii and around the motor. Centrifugal starting switches are not used on such motors because any arcing in the gas and oil atmosphere would be' detrimental, and also because the units are permanently sealed and cannot be serviced or repaired in the field. In place of a centrifugal switch, an external relay is used to start hermetically enclosed motors. Refer to Glossary at end of chapter. Motors and Motor Controls 865 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 automatic push-button starting. Fig. 4. Recommended Controls fob 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 fine current going to' the motor. When the motor is started, the inrush current to the running winding, passing through the relay coil, causes the contacts to close, and , applies power to the starting winding. As the motor comes up to speed, the current decreases until at a definite calibrated value of current 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 usually started with a voltage-type relay. In this method; of starting the relay coil is connected in parallel with the starting winding. When power is applied to the line, the relay does not operate because it is calibrated to operate on a higher voltage. As the motor comes up to speed, the voltage across the starting winding and relay coil increases in proportion to the, motor speed. At a definite voltage corresponding to a pre-selected speed, the relay operates and opens its contacts, thereby opening the starting 866 CHAPTER 39 I ' 19S2 Guide winding circuit. The relay then keeps these contacts open because there is sufficient voltage induced in the starting winding, when the motor is running, to hold the relay in the open contact position. . CONTROL FOR ALTERNATING CURRENT MOTORS Squirrel-Cage motors are usually linestarted where power company ' limitations permit: In sizes up to 5 hp at 220 volts, or 7-\ hp at 440 volte, polyphase motors may be started, by means of manual switches haying 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 COMBINATION LINESTARTER ...Motors and Motor Controls 867 In.applying reduced voltage starters to synchronous motors it should be remembered that; since these motors are 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 tor insure development of sufficient1 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. I ,, . SPEED [ X I REGULATING *J CONTROLLER UNIT ASSEMBLED CONTROL Fio. 5. Recommended Controls fob Wound Rotor Motors 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. _ Wound Rotor motors require control of both primary and secondary circuits. The primary* control may be the same as for squirrel-cage motors, manual or magnetic, at full voltage. Secondary* control pro vides means of varying secondary resistance for starting and speed control. The secondary controller should be specified for starting duty only,, or for , 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 speci fied. Fig. 5 illustrates recommended control practice for wound rotor motors. ' . Synchronous motor starters should provide pull-out protection, auto 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 field.control, but require hand operation for closing the line contactors to start and transfer to full voltage. % Refer to Glossary 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 Motors 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 868 CHAPTER 39 1952 Guide " be 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, paper 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 simi lar 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. 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 open 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 starting inrush current, however, is limited in many cases by regulations of power companies because of the voltage fluctuations which may be caused by heavy current surges. It is therefore often necessary to reduce the starting current below that obtained by across-the-line starting. The power supplier should be consulted to determine the allowable inrush cur rent for any given location. The choice between full voltage and reduced voltage starting is governed almost entirely by inrush current limitations. The starting torque of all motors varies with the starting current, and it is therefore necessary to insure that the motor is supplied with sufficient current to develop enough torque to accelerate the load. In present practice overload protection of motors is obtained by use of thermal overload inverse time limit type protection. The usual setting of such protection devices is not to exceed 125 percent of rated full load current for open 40 C 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 tion is ended. The second type, called low voltage protection, causes the motor line contactor to drop out on low voltage, but prevents restarting Motors and Motor Controls 869 when the voltage returns to normal except by the action of an operator. This latter type of protection is desirable where it is necessary for the operator to make initial starting adjustments on the machine. Manual control for an alternating or a direct current motor is usually located near the motor. When so located an operator must be present to start and stop or change the speed of the motor by operating the control mechanism. Manual control is sometimes employed only as a device to . give overload protection, and another device is employed to start and stop the motor. Manual control is used particularly on .small motors which operate unit heaters, 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 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 striking and running along a hori zontal or inclined surface. Splash Proof motors (50 C rise) are so constructed that drops of liquid or solid particles falling on the machine or coming toward it in a straight line at any angle 870 CH/AP' TER 39 1952 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, nonventilated machines, except that exterior cooling is provided by means of a fan or fans integral with the machine. 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 surrounding 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 m 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 Bpeed 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. Beteen 600 and 1200 rpm the rated horsepower increases directly with speed from 20 to 25 hp. . (5) Motors may also be rated 1 hour with temperature rise of 50 C with the higher . horsepower rating (see 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 . yertical Mountings are available for such applications as pumps and agitators. This type of application may require a special umbrella-type hood to protect against dripping liquids. Ylanged 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 close coupled pump and similar applications. CHAPTER 40 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 an international standard, the decibel (db) is the unit for expressing sound pressure levels. The sound pressure level, in decibels, is given by the relation: ' db = 20 logio () \0.0002) CD where P the sound 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 in 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: 871 . 872 CHAPTER 40 1952 Guide db = lOlogio^^^ (2) where I -- the sound intensity in watts per square centimeter. ' The reference intensity is 10~l* watts per square centimeter, coinciding with the reference pressure of 0.0002 dynes per sq cm or 2 X 10"* 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 of 0.0002 dynes per square centimeter, or to a threshold of 10~le 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 meter1 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 and 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 leastthree decibels, and preferably five decibels, below that found in Item I. 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. Sound Control 873 Table. 1. Decibel Scale vs. Sound Pressures and Sound Intensities Decibel LEVEL : Pressure dynes per sq cm - ' .. Intensity watts per sq cm -- . Decibel Level ., ' Pressure' dynes per sq cm' Intensity ' ` watts per.sq cm - 0 0.000200.- 1.000.X 10- .. 40 . 0.0200 1.000 X 10-" i 0.000224 1.259 X 10"" 50 0.0631 1.000 X 107" 2 0.000252 1.585 X 10-' 60 0.200 1.000 X 10-" 3 0.000282 2.000 X 10~" 70 0.631 1.000 X 10-= 4 0.000317 2.520 X 10"" 80 ,, 2.00 1.000 X 10- 6 0.000399 8 0.000503 . 10 .0.000631 20 . 0.00200 30 0.00631 4.000 X 10-" 6.310 X 10-", 1.000 X io-" 1.000 x io- 1.000 X io-" 90 . 6.31 100 , - 20.0 110 . 63.1 120 200.0 . .. ...... 1.000 X 10-' i,goo x-io- 1:000.x ir6 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- ween 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 transmission is through dividing walls, it will be. necessary to'refer to published .data on losses through, standard building constructions.3 Information concerning the sound levels created by ventilating and air conditioning, equipment such as fans, motors, air washers and similar items, has riot yet been completely established. However, numerous manufacturers are in a position to supply such data upon many of their products. Additional information is being collected. Uniformity in method of test and 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 of Fan Manufac turers. The Code prescribes, that .the sound level shall be measured by the flat response network of the sound-level meter. . Readings on the 40 db arid 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 needle reading of the meter. The fast 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 sourid level of the fan is 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- 874 CHAPTER 40 1952 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, sprayB, 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 tern. f. 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 2 3 4 1. Determination of acceptable room noise level resulting from the operation of the equipment. . 2. Determination of noise 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 system. 4. Selection of the proper sound treatment for the duct system. The difference in decibels between the overall attenuation required and the nat ural attenuation (3) is the additional sound attenuation to be provided by absorp 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 875 Table 2. Typical Sound Levels* Weighted Network Response Rooms Sound Level in Decibels to be Anticipated ` Min. . Represent ative . Max. Sound Film Studios......................................... ..................... Radio Broadcasting Studios................................................ Planetarium............................................................................. Residence, Apartments, etc.......................,....................... Theaters, Legitimate............................................................ Theaters, Motion Picture....................... :........................... Auditoriums, Concert Halls, etc........................................ Executive Offices, Acoustically Treated Private Offices'; General Offices.................... ................................................... Class Rooms.................................................. -- ............ Libraries, Museums, Art Galleries.................................... Public Buildings, Post Offices, etc.................................... Court Rooms............................................................................ 10 10 15 33 25 30 25 25 30 35 50 25 30 30 45 30 Upper Floors Department Stores....................................... Stores, General, Including Main Floor Dept. Stores.. Hotel Dining Rooms.............................................................. Banking Rooms...................................................................... Office Machine Rooms.......................................................... - 40 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............................................................. .............. Vehicular Tunnel.................................................................... 60b 55b 50 75 75 70 65 65 85 80 80 75 80 95 90 * These values are tentative. More detailed measurements by D. F. Seacord, Bell Telephone Labora tories (Journal Acoustical Society of America, Vol. 12, pp. 183-187, 1940) give average values and standard deviations of room noise in residences, offices, stores, factories, etc., in large American cities. b 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 levels 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- 876 CHAPTER 40 1952 Guide Table 3. Average Sound. Conditions in Various .Types op Rooms and . Buildings*., Flat Response Network Type op Room ob Building ~ , Decibels Broadcasting studios...... ........................................................... 20-30 (very quiet) Residences, churches, libraries, apartments, auditoriums, execu-' " tive offices, class rooms...!................................... . . ' .. 40-55 (quiet) Hospitals, court rooms, quiet offices, show rooms, small retail stores, tea rooms, hotel dining rooms, foyers, upper floors of department stores, reereation rooms....................................... .. Banking rooms, beauty salons, barber shops, general offices, restaurants, main floors of department stores, cocktail lounges, dairy bars, tap rooms, billiard halls............... ... ___ . 45-60 (moderately . quiet) 55-70 . (average) : Gymnasiums, transportation waiting rooms, drug stores, grocery stores, cafeterias, super markets, recreation halls, 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. . Representative sound 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. . In general, if the sound level in the space resulting from the operation of the air conditioning equipment only, is equivalent to, or less than, the typical level (from Tables 2 or 3 or, bettor 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; to minimize possible annoyance due to introduction of single'or distinctive frequency components from the equipment, it is desirable to design for an equipment sound level of at least 5 db below the typical space level. : NOISE GENERATED BY FANS , Noise generated by fan wheels may be divided into two classifications, rotational noise and vortex noise.. The rotational noise may be described -.Sound Control 877 Fig. 1. .Sound/Level Characteristics of Typical Centrifugal,. ; Multi-Blade Ventilating Fan as that due to the thrust and torque applied to the air. Vortex poise is that due to the shedding of vortices from the blade, and is dependent.on the angle of attack, velocity, air' turbulence, and blade shape. Vortex noise is due to pressure variations on the `blade as a. result of variations of ' air circulation. Given the noiselevel at'the outlet or'inlet of one type of fan''construction under specific conditions of aze;'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. . .. .' db (change) = 50 ^ ': (3) 2. For constant pressure and tip speed, the noise.level of a given type of fan will increase with increasing fan size. /Size\ . db (change) -- 20 login \Sizei / (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. The noise of a given fan is not constant at constant speed if the air delivery changes due to change of resistance. In general, a backward' curved blade fan is lowest in noise at or near 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 of the curves denotes the range of minimum sound emission. The selec tion and application of the fan should be made within such good applica tion range where quietness of operation.is of major consideration. The various types of fans available possess individual sound level character istics throughout their range of possible operation. Recourse to standard 878 CHAPTER 40 1952 Guide Sound Control Fio; 2. Sound Level Characteristics op Typical Vaneaxial Fan test rating information should be made to arrive at the sound emission of a particular type. . 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'shown in Fig. 2. The sound level of a particular fan is primarily governed, by the operating speed required to produce a desired delivery against the system static pressure. Fig. 3 illustrates the variation of fan sound level in deci bels with operating speed, the fan operating in connection with a conven 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 whiph extend over a broad field. Fig. 4 illustrates the general scope of sound levels of centrif ugal ventilating fans over a wide range of volumetric capacities and static Fig. 3. Relation op Sound Level'to Operating Speed of a Centrifugal " Ventilating Fan Fig. 4. Typical Sound Levels at Point of Minimum Sound Euibsion for ' Centrifugal Ventilating Fan 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 DutUs. The attenuation of sound in straight sheet metal ducts is a function of the length, shape, and size of the duct.4 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 placp 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 <Iuct 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 Duct Sub, In. Attcnuation fsb Ft, db 6x6 24x24 72x72 0.10 0.05 0.01 , 880 CHAPTER 40 1952 Guide Table 5. Attenuation op Elbows* Elbow Size lN.b. . Attenuation peb Elbow, db Verv small. . .. Large................ 3 3 to 15 .2 15 to 36 1.5 36 plus : i * The attenuation in vaned elbowB should be considered the same aa in elbows having the same dimen sions as the radius of curvature of the vanes. If the vanes are lined for the purpose of damping any vibra tions in them, one third may be added to the attenuation values listed. ' b These attenuation values are based on elbowB having a center line radius 1.5 to 2 times the diameter or width of the duct. The attenuation will be greater if the ratio is less than 1.5 and less when the ratio is greater than 2. This attenuation is a function of the total grille area (supply and return) and the total sound absorption of the room in sabins: (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 coirespondihg 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: : .. ., n / Attenuation between \ ,,,, . Total Room Absorption in Sabins' * V grilles and room 10 lo&0 Total Grille Area . " ,,,N (5) ' Values in Table 7 approximate the attenuation for various 'fates 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. Selection of the Absorptive Material . ; When a sound wave impinges on the surface of a porpus material, a. 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: : Table 6. Attenuation at Duct Branches or Outlets Ratio Branch Duct + Outlet Abba Supply Duct Area 1.00 1.20 1.35 1.50 1.75 Sum op Branch Areas Supply Duct Abba Attenuation per Transformation, db 0.0 0.8 1.3 1.8 2.5 Sound Control 881 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 an 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;5 (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 Between Grilles and RooU: / Outlet VBLOCtTT PPM 500 , 760 1000 , 1250 An Changb . Min. 5- 10 16 20 '5 10 15 20 ' 5 10 16 20 6' ' 10 15 . 20 Live Room* ot - 0.05 db ii 14 16 17 13 16 18 19 14 17 19 20 ,16 . 18 20 21 Medium Room o ~ 0.15 db 16 19 21 22 . Dbad : Room* a - 025 ' db . : ....... 18 21 23 24 . 18 21 23 . 24 19 22 24 25 20 23 25 26 20 . 23 26 26 . ' 21 - 24 . ,28 ` 28 22 25 27 28 ' * Average absorption coefficient for the room. ` b Live room-average absorption coefficient 0.05. Bare wood or concrete floor--hard plaster walls and ceiling--minimum of furniture. . 0 Medium room-average absorption coefficient 0.15. Carpeted floor, upholstered furniture, hard plaster walls aud ceiling or bare room with acoustically treated ceiling. d Dead room-average absorption coefficient 0.25. Heavy carpeted floor. Walls and tiling aooustically treated. 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.father 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 accuratejy 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 882 CHAPTER 40 1952 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.extentjyith 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. . Duct Lining By far the most commonly used method of obtaining sound absorption in ventilating systems is to line the duct with absorbing material. It is 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 for the same area of applied acoustical material. Subject to certain restrictions, the attenuation of a fully lined duct to single-frequency sounds 'may be expressed by the approximate Equation 6:7 . where ' R = 12.6L -M o' * A (6) .. , 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 from 9 x 9 in. to 18 x 18 in., for cross-sectional dimension ratios ofT: 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 1 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. It is also possible to calculate the absorption by a very complicated 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 883 Table 8. Attenuation Data fob Typical 1 in. and $ in. Thick Duct Lining Boabd ' Frequency cycles per second 1-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-? A P 4.9 L~ A 7.6 .A p . 9.2 L -- A p 9.1 L^r A J-Inch Thickness . Absorption Coefficient a O1*4 0.13 0.25 0.40 0.72 0.78 0.06 0.15 0.28 0.63 0.71 Attenuation. db p 0.8 L^r A p 1.9 Lg 3.5 Z, A p 7.9 A p 8.9 L -r 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 Fig. 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. ' 0.1 02 03 0.4 OA 0B 1 2 3 4 6 8 10 ATTENUATION. DECIBELS PER FT Fig. 5. DSound Attenuation fob Vabious Absobbing uct Linebs 884 CHAPTER 40 1952 Guide Sound Control 885 .6Fig. Acoustic Treatment op Ducts A. Unlined metal duet. B. Absorption lined duct (Case 1). 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 cases. . ' '- Sample Calculations for Duct Treatment - 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) .......................... ....................... 40. db Required attenuation......................... ....................-.. ; . . .............37 db - Solution: -Natural attenuation of supply duct. .. 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) 2 x 1..................................... 2.0 db : Attenuation grilles to theater air change 10 inin (Table 7) outlet 1 ' velocity 1000 fpm . ....................................................................................... 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 duct, either in the form of duct wall lining or rectangular cells of the plate or cell absorber arrangement. A similar analysis of the return duct system showB 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 2: A 10 x 20 in. duct 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 duct 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 0.40> < - 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 20 6 Fig. 7. Absorption Plenums With and Without Sound Cells Case 2. (Two 1 in. splitter plates, 3.channels each 20 in. X ^ in.). From Equation 6, R -- 12.6 X 12 X X 0.4b1-4 = 29 db. 667 . Additional attenuation may be obtained by using additional splitter plates or use of egg-crate arrangement of absorbing materia) 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. , Plenum Absorption in Sabins ' db (Attenuation) = lOlogu 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 are also employed in large systems with long runs where only a few outlets near the fan require treatment. Frequently outlet cells are the only means of 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 Sound Control 886 CHAPTER 40 1952 Guide 887 F . 8iq . Outlet Cells fob Pan Outlets ob Gbilles a constant rate.u 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, arid 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 ' ri)........................db (change) = 50 logic 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. ]db (change) - - 25 logic (Total Pressure)i (Total Pressure)i (9) The resultant room noise level can be approximated by Equation 10. -[ ]Room Level Noise Level at Total Room Absorption in Sabins -- 10 logio Face of Grille Total Grille Area (10) 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. 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 found possible to present these data with sufficient practical accuracy as a family of uniform curves, as illustrated in Fig. 9, which are based 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 lever. , 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 30) 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 -s- 725 or 3.31 sq ft. If the room absorption had been greater, the previously selected velocity of 725 fpm would be safe, since the sound level reduces. If the room absorption had been 200 sabins, a correction of plus 1.3 should.be made by reference to Jig..10, and-the 888 CHAPTER 40 1952 Guide permissible velocity becomes that corresponding to a total sound level of 36.3, or approximately 800 fpm. . 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 Babins, 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 fined 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 pf 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 Sound Control 889 , Fio. 10. Room' Absobption Cobbection Chabt . . means of preventing the transfer of noise into the air stream. Inside lining may also be used in ducts to absorb noise which reaches the air stream from equipment such as fans, sprays and coils; noise due to eddying currents set up by elbows, dampers and similar obstructions; and noise transmitted from room to room where there is a common duct system. , CONTROLLING VIBRATION FROM MACHINE MOUNTINGS It is impossible to select equipment which will operate without producing some mechanical noise and, since the equipment must be mounted in a building, it is'probable that a part of this noise wilj be transmitted to the building to such a degree as to make noisy conditions, in the rooms which are to be air conditioned: ' Much of this noise may be transmitted by the duct if it is rigidly con nected to the fan outlet. It is coinmon practice to make the connection between the fan and the duct with a canvas sleeve which effectively restricts noise at this point. Noise may also enter the building through the mount ing of the motor and the fan. Flexible mountings should be provided in all installations, but these mountings must be carefully designed so that they will actually reduce the energy transmitted between the machinery and the supporting floor. If a flexible material is used, it is desirable to investigate the installation so that it is not short-circuited by through bolts which are improperly insulated, and by electrical conduit which is not properly broken and is attached both to the equipment and to the building. The flexible mounting, if improperly engineered, may actually increase the energy transmitted between the equipment and the supporting floor. In the proper isolation of vibration, which is usually in the lower range 890 CHAPTER 40 1952 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: where T -- transmissibility of the support. / = frequency of the vibratory force. fn -- natural frequency of the machine unit on its support (damping = 0). Equation 12 showB 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 resonant frequency, where / = /,, the transmissibility becomes infinite. This is not true in practice because all materials have some internal damping effect. However, operating at or very close to the resonant frequency is always serious as forces and stresses may be multiplied 10 to 100 times.. As the disturbing frequency becomes greater than die natural frequency, the transmissibility becomes a smaller quantity, and at the value of ///,, = \/2 it again has the value of unity. Beyond this point true isolation is first accomplished. At a ratio of 3 to 1 for / to./n 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 results for effective vibration control, but for the lower speeds as experienced with compressor work the higher ratios become uneconomical. For a given installation, the speed of the compressor is fixed by. the speci fications; therefore the value of / is fixed. That leaves only /,, 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 offa 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 /D can be determined by Equation 13: .TM 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). 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 vari ous static deflections, is a curve showing the worst possible conditions or resonant conditions. ," Plotting another curve CD, which is \/2 times curve AB, shows the area MCDN in which the resilient material or mounting does more harm Sound Control 891 Fig. 11. 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 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 + 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, it is desirable to design for at least 8 springs and one or two spares for cases of un known 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 is also important. For the slow-speed type compressor, a common speed found in practice is 360 rpm. For speeds below this, isolation should not be attempted except under careful supervision. Referring to Fig. 11, it is 892 CHAPTER 40 1952 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 isolation 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 imbalanced 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 modern 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 American Standard for Noise Measurement, Z24.2-1942, American Standards Association. * American Standard for Sound Level Meters for Measurement of Noise and Other Sounds, Z24.3-1944, American Standards Association. ^ .. . * Sound Insulation of Wall and Floor Constructions (U. S. Department of Commerce, National Bureau of Standards, Building Materials and Structures Report BMS17 and Supplement). ' 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, 1942, p. 267). # For coefficients of commercial sound absorbent materials see Bulletin Acoustical Materials Association, 919 No. Michigan Ave., Chicago, IU. , * SoundPropagation inDucts Lined with Absorbing Materials, by L. J. Sivian (Journal Acoustical Society of America. Vol. 9, 1937-38, pp. 135-140). . .. . 7 The Absorption of Noise in Ventilating Ducts, by Hale J. Sabine (Joumal Acoustical Society of America, Vol. 12, p. 53, 1940). , . Sound Absorption in Rectangular Ducts, by L. L. Beranek (Journal Acoustical Society of America, Vol* 12, pp. 228-37, October, 1940). .. * The Transmission of Sound Inside Pipes, by Philip M. Morse (Journal Acoustical Society of America, Vol. 11. pp. 205-210, October, 1939). .. to The Prediction of Noise Levels from Mechanical Equipment, by J. S. Parkinson (Beating and Venti lating, March, 1939. pp. 23-26). ' Methods of Rating the Noise from Air Conditioning Equipment, by J. S. Parkinson (A.S.H.V.E. Jour nal Section, Baiting, Piping and Air Conditioning, July, 1940, p. 447). ' u The Noise Characteristics of Air Supply Outlets, by D. J. Stewart and G. F. Drake (A.8.H.V-E. Trans actions, Vol. 43, 1937, p. 81). . .. i CHAPTER 41 ELECTRIC HEATING Resistors, Heating Elements, Electric Heaters, Unit Heaters, Central Heating and Air Conditioning,'Electric Boilers, Electric Hot Water Heating, Heating Domestic Water Supply, Calculating Capacities, Induction and Dielectric Heating, Power Problems ELECTRIC heating deals with the conversion of electrical energy into heat and the distribution and practical use of the heat so produced. In certain regions, where the cost of electricity is favorable, electric heating is used extensively. Its use is also frequently dictated by special con ditions. . Definitions of the terms Electric Resistor, Electric Heating Element, Electric Heater and other terms applying to heating practice, will be found in Chapter 1. RESISTORS AND HEATING ELEMENTS Commercial electric heating elements usually have solid resistors such as metal alloys or non-metallic compounds containing carbon. In some types of electric boilers, water forms the resistor which is heated by passing an alternating electrical current through it. In one type of heating element, the resistors are exposed coils of nickelchromium wire or ribbon, or non-metallic rods, mounted on insulators. This type is used extensively for operation at high temperatures for radiant heat, or at low temperatures for convection and fan circulation heating. Some elements have metallic resistors embedded in a refractory insulat ing material, encased in a protective sheath of metal. Fins or extended surfaces add heat-dissipating area. Elements are made in many forms, such as strips, rings, plates and tubes. Strip elements are used for clamp ing to surfaces requiring heat by conduction, in some types of- convection .air heaters, and in.low temperature radiant heaters. Ring and plate elements are used in electric ranges, waffle irons, and many small air heaters. Tubular elements may be immersed in liquids, cast into metal, and, when formed into coils, used in electric ranges and air heaters. Cloth fabrics, woven from flexible resistor wires and asbestos thread, are used for many low temperature purposes such as heating pads, aviators' clothing and radiant panel heating installations. Special incandescent lamps are used as heating elements in certain applications where radiant heat is desired. These use carbon or tungsten filaments as resistors, and are designed to produce maximum energy in the infra-red portion of the spectrum. ELECTRIC HEATERS Conduction electric heaters, which deliver most of their heat by actual contact with the object to be heated, are used in such applications as aviators' clothing, hot pads, soil heaters, and water heaters. Conduction - 893 894 CHAPTER 41 1952 Guide -heaters are useful in conserving and localizing heat delivery at definite points. They are not suitable for general air heating. Radiant electric heaters, which deliver most of their heat by radiation, have heating elements with reflectors to concentrate'the heat rays in the desired directions. They-are not satisfactory for general air heating, as radiant heat rays do not warm the air through which they pass. They must, first be absorbed by walls, furniture, or other solid objects which then give up the heat to the air. For a discussion of electrically heated panels as applied to radiant heating, see Chapter 23: . Gravity convection electric heaters, designed- to induce thermal air circula tion, deliver heat largely by convection, and should be located and used in much the same manner as steam and hot water radiators or convectors. They generally have heating elements of large area, with moderate surface temperature, and are enclosed to give a stack effect to draw cold air from the floor line. The flexibility possible with electric heating elements should discourage the use of secondary mediums for heat transfer. Water Power supply Electric Heating 895. If the line voltage is more than 120 to ground, it is advisable to supply the thermostatic control circuit through a transformer. CENTRAL HEATING AND AIR CONDITIONING Electric heating elements can be used for the prime source of heat in a central fan heating system or in the heating phase of an air conditioning system. They can be used in the same manner as steam heating units for tempering, preheating or reheating the air at the main supply fan location, and as booster heaters at the delivery terminals of the duct system. In the humidification phase of air conditioning, electric heating elements can be used to provide moisture by the evaporation of water. , In coordinating the input of heat energy and the volume of air circu lation, a basic difference between electric heating and steam heating enters into the problem. Steam is approximately a constant-temperature and steam add nothing to the efficiency of an electric heater and entail expensive construction and maintenance. Induction and dielectric heaters are described in a later section. UNIT HEATERS Electric unit heaters include a built-in fan unit which circulates room air over heating elements. They are adapted to the same uses as other types of unit heaters, if conditions are favorable to electric heating. They are very adaptable for heating of small offices, locker rooms, etc., in other wise unheated buildings. In small unattended equipment rooms, thermo statically controlled electric unit heaters are frequently used to maintain a temperature above, freezing. The best location for electric unit heaters depends upon local conditions. Various designs and arrangements are available, as with steam unit heaters (see Chapter 24). . The arrangement of the wiring circuits is very important. In principle, they are all the same and include as essential elements, a magnetic control contactor, a thermostat, and a master hand switch. Ail heaters should be designed with a safety thermal trip wired in series with the magnetic con tactor, and with the hand switch and thermostat. A typical wiring diagram for single phase power supply is shown in Fig. 1. A main disconnect switch should be provided. For three-phase power supply, a 3-pole contactor should be used with the heater arranged for 3-phase connection. On large sizes, separate over-load protection for the motor should be provided. Fio. 2. Resistance Type Boiler fob Steam ob Hot Wateb source of heat for any given pressure, and a change in air volume flowing over steam coils does not greatly affect the temperatures of the coil sur face. 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 input of energy. If the volume of air flow over electric heating elements is changed, and no change is made in the electrical power input, there will. be a corresponding change, in the 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 force the air to accept all the heat. With electric heat the total heat is constant unless some compensating action is performed by controls. Auto matic variation of the electrical heat input synchronized properly with the air flow, can be successfully accomplished by various special methods of control. By-pass dampers as used with steam units will not control electric heat. Electric heaters are useful in balancing the heat distribution in central fan systems. Even in those instances where steam is the principal heat source, the temperature of individual rooms can be controlled locally by separate electric booster'heaters. These heaters can be installed in branch ducts or behind the air outlet grilles in each room. With this arrangement, the central heating unit distributes air at an average temperature, con trolled from a thermostat centrally located, such as in the main return duct. The electric booster heaters may be controlled by thermostats 896 CHAPTER 41 1952 Guide mounted in each individual room to permit the occupant to maintain any desired temperature independent of the rest of the building. ELECTRIC BOILERS ' .... Steam or hot water generating boilers using electrical energy are entirely automatic, and are well adapted to intermittent operation. Small electric boilers usually have heating elements of the enclosed metal resistor type immersed in the water. Boilers of this construction may be used either with direct or alternating current since the heat is delivered to the water by contact with the hot surfaces. To lessen the likelihood of binning out of heating elements, they should be of substantial construction, with a low heat density per unit of surface area, and provision should be made for Electric Heating 897' well-insulated, pressure type steel tank, equipped with electric heating elements, automatic time switches, and automatic limit controls for tem perature and pressure. The heating system installed in the building may be of any standard design. A system of this kind requires very careful desijgn .to avoid excessive overall radiation losses during periods of low heat demand. It is also important to provide for sudden changes in heat demand. A typical water heating boiler is illustrated in Fig. 2. HEATING DOMESTIC WATER BY ELECTRICITY Electric water heaters of the automatic' storage type for domestic hot water supply are simple and reliable. In many sections of the country low electric rates have been established by the electric utilities to secure this load. In many localities, electric`rate schedules divide the current . Fig. 3. Diagrammatic Arrangement of an. Electrode Boiler . cleaning off deposits of scale which. restrict the heat flow. A typical resistance type of steam or hot water boiler is shown in Fig. 2. . . Large electric boilers are usually of the type employing water as the resistor, using immersed electrodes. With this type only:alternating cur rent can be used, as direct current would cause electrolytic deterioration. Such a type of electrode boiler is shown in Fig. 3. . . Electric steam boilers are useful in industrial plants which require limited amounts of steam for local processes, and for sterilizers, jacketed vessels and pressing machines which need a ready supply of steam. It sometimes is economical to shut down the, main plant fuel-burning boilers when the heating season ends, and to supply steam for summer needs with small electric steam boilers located close to the operation. ELECTRIC HOT WATER HEATING Electric water heating, using an electric boiler in place of a fuel-burning boiler, like electric steam heating, is generally 'confined to auxiliary or other limited applications. The use of insulated water-storage tanks, in which to store heat generated by electricity during off-peak hours at extremely low rates, is a development which has some special applications. In this system of heating, the primary storage tank is simply a large, Fig. 4. Piping Arrangement for Connecting Electric Water . Heater to Fire-Box Coil . Fig. 5. Domestic Hot Water Heater for Off-Peak ` Service used for water heating into two classifications, regular and off-peak. A time switch automatically limits use of the off-peak heating element to the hours of off-peak load, while the regular heating element is a stand-by at all times. Storage of this two-element type of water heater is larger than average to help carry over the periods when the off-peak element is timed out. Some utilities now offer a schedule which, beyond a stipulated minimum, lowers the rate for all electric service if an electric water heater is installed. . Competition with other fuels, especially gas, seems to be the major controlling factor in the use of electricity. The first cost of electric storage heaters is greater than for gas, owing to the need for larger tank storage due to off-peak service and slower recuperating capacity. '; In residential work, to. effect a saving in the cost of operation, it is sometimes desirable to use a furnace coil or indirect heater in connection, with an electric water heater. In this case it is important to make the proper connections in order to benefit by any heat obtained from the furnace, and at the same time to prevent dangerous overheating. The proper piping connections are shown in Fig. 4, and in this' case the electric' heater will only furnish heat when insufficient heat is supplied from the furnace. This , arrangement has a further advantage in the summertime in that the bare tank through which the cold water passes on its way to 898 CHAPTER 41 1952 Guide . _the electric heater serves as a tempering tank, absorbing heat from the basement air and requiring the use of less energy in the electric heater. A typical domestic hot water heater as shown in Fig. 5 is arranged with upper and lower heating elements for the usual type of off-peak heating service. The lower heating element is under the control of the. off-peak time switch. However, the upper heating element is usually connected to the line so that, in case the supply of hot water in the tank becomes . exhausted, the top thermostat can turn on the top heater and heat a small supply of water. The top heater will not heat the water in the tank below its location, but when the off-peak period arrives the, lower heater is turned on and the entire tank becomes heated. CALCULATING CAPACITIES In calculating electric heating capacity, one kilowatt is equal to 3413 Btu per hour or 14.2 sq ft equivalent direct steam radiation. All of the energy applied to an electric, resistor is transformed into heat. The output of an electric heater is a fixed constant, unaffected by the temperature of the surrounding air, and the total load on an electric heating system is the total wattage of the connected electric heaters. ELECTRIC HEATING BY INDUCTION AND DIELECTRIC MEANS These methods differ radically from resistance heating. They have many important industrial uses, and open up a whole new field of special applica tion where extreme speed or control of heat location are vital. Metals and other electrical conductors can be heated by induction. The work is placed in an alternating magnetic field within, or adjacent to, a coil, and heat is produced in the body of the piece by eddy currents. While induction heating has certain limitations, it has great advantages in certain applications- such as melting metals, forging, brazing, heat treating and particularly for localized heating and zonal hardening of metals. It is possible to apply localized heat so rapidly that conduction cannot draw the heat away before it has time to accomplish the desired purpose at a par ticular spot. Surfaces and local areas can be hardened without distortion or scale formation. . Commercial 60-cycle alternating current may be used in special cases, such as induction heating of large pressure vessels hut special higher fre quency generating equipment is generally required. It should be carefully selected for the particular kind of work to be done. Motor- generators with frequencies in the vicinity of 250 cycles, per second, are used, for many melting furnaces. Motor-generators having frequencies between 2,000 and 10,000 cycles per. second, are generally used for heat treating and hardening sizeable parts. For heating or brazing thin sections or small parts, electronic tube oscillators, spark discharge oscillators, or mercury arcs are used to produce frequencies ranging up to 500,000 cycles per second. Work coils used with high frequency induction heating are generally copper tubes through which cooling water is circulated. These must be specially designed for each application. - Non-conductors of electricity can be heated internally by dielectric means by placing the materials in a high frequency electrostatic field between electrode plates. This process is distinctly different from the induction heating process. High voltages and very high frequencies, often up to 50 million cycles, are needed to produce the desired rate of Electric Heating 899 heating. The main field for dielectric heating is with materials which are poor thermal conductors. Food can be sterilized, plywoods bonded,. plastics heated, granular or crystalline - material dehydrated, deep-pile fabrics dried, and countless other products heated quickly and uniformly. Dielectric heating is well suited to many continuous production processes, as the materials can pass through the heating field quickly and without the necessity of contact with the electrode surfaces. . POWER PROBLEMS The cost of electric energy varies because of several factors. Distribu tion costs differ for large and small users. The fact that electricity cannot be economically stored, but must be used as fast as generated, makes it impossible to operate electric plants at uniform loads; hence, even the time of use may affect the cost of electricity. Special low rates are some times available during certain prescribed hours of use. .. Since cost of production and distribution depends not only upon the quantity of energy used but also upon the maximum rate of use, electric energy is often sold on a demand rate basis. In some cases, the demand charge is based upon the rated connected load; in other, cases, upon the maximum demand indicated by a demand meter. Homes are almost universally Supplied with lighting current of 115 volts, which can only be used economically for small heaters. Usually the service lines will not permit more than plug-in devices. The National Board of Fire Underwriters permits approved heaters of 1320 watts or less to be plugged into approved baseboard receptacles, but such heaters cannot be served on a circuit supplying much other load without overloading the circuits. There is an increasing trend toward supplying homes with three wire 115-230 volt service. Where homes have such service, larger heaters can be installed. For industrial purposes, heaters should be designed to use polyphase power, which is usually supplied at 208, 220, 440 or 550 volts. All polyphase heaters should be balanced between phases. In ordering electric. heaters, proper voltage must be specified, as the heat produced , will vary as the square of any variation in voltage. BIBLIOGRAPHY Electric Elements Well Adapted to the Air Conditioning Heating Cycle, by L. P.' Hynes (Heating, Piping and Atr Conditioning, January, 1940, p. 29). Electric Heating for Los Angeles Building (Heating and Ventilating, 37:50-l; June, 1940). - House Heating Load Characteristics as They Affect Wiring Costs, by Jack B. Cochran (Electrical World, April 12, 1947). Low-Voltage, High-Current Radiant House Heating {Electrical World, January 3, 1948, p. 39). Radiant Heating by Electricity, by L. N. Roberson {Heating and Ventilating, September 1946, p. 89). Radiant Heating, by F. M. Tiller {Chemical Products, March-April 1945). Applications of Radiant Energy (Lighting Handbook, Illuminating Engineering Society, 1947, Section 16). ^Industrial Applications of Infra-red, by J. D. Hall (McGraw-Hill Book Co., Faster Baking and Drying with Infra-red Heat, by Paul H. Goodell {Electrical World, June 21 and July 5, 1947). 900 CHAPTER 41 1952 Guide ' Electrical Radiant Heat vs. Steam Convection, by Douglas Dow (Electrical World, August 10, 1940, p. 61). . .. r.;Infra-red vs.i Convection Ovens-for Drying Paint Coatings, by J. F.Gschwind (Industrial Finishing, September 1945). , TM' --. . . Industrial Electric Resistance Heating, by, Lee. P. Hynes (American Institute of Electrical Engineers, P.aper No. 48^247). , ........... .. . Recent Advancements in Industrial Heating Processes and Equipment, by Eugene Mittelman (Industrial Heating, September 1944). Heating of Non-magnetie Electric Conductors by Magnetic Induction, by R. M. Baker (Electrical Engineering, June 1944). 1 Operating Experience" with HF Heating, by Henderson C. Gillespie (Electronic Industries, February 1944)'. .- : . . .> . Unusual Methods of'Applying Electronic Heat, by E. D. Tillson (Electronics, April 1945). . - . ,. Dielectric Heating, by T. W. Dakin and R. W. Auxier (Industrial and Engineering Chemistry, March 1945). ; Induction and Dielectric Heating, by Kennard Finder (Electrical Engineering,. February 1947)............ , : t.. . , ... .. ... High Frequency Heating in the Radio. Spectrum,-by. W. C. Rudd (Electrical Engi neering, June 1947). Standard Handbook for Electrical Engineers, McGraw-Hill Book Co. CHAPTER 42 CORROSION AND WATER FORMED DEPOSITS, CAUSES AND PREVENTION Definitions, Classification and Characteristics of Water, Causes and Prevention of Scales and Sludges, Causes 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 used to remove it from the surface on which it is deposited. Scale, which may or may not. adhere to the underlying surface, is usually 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 toremove 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 .barnacles1 or mussels: Slimes 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, formed 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 de8tructi6n-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. - 901 902 CHAPTER 42 1952 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. . ' " Mineralized Waters All the waters found in streams, wells, lakes, and the ocean are mirteralized. 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 '. ' and Used Industrially in the USA Location ob Abba1 ,b . Substance .. Unit a) (2) (3) (4) (5) (6) (7) 09 (> fiiliwt....................................... '............. fiftlwnm................. ............................. Magnesium................. :............ ........... Sodium.................................................. Potassium........................................... SiO* Fe Co Mg Na K 202611 60 102 371 100 09 202 14 2 6521 . 386 71 62 18 44 92 3841 96 27 183 18 23 21150 155 46 78 3 400 111..030000 400 Sulphate............................................... HCO* SaO* ' NOj 112401 11230 12129 103 202 135 132 339 8140 13 313214 2800 5241291 .1 210 389 117 3 150 2.700 19.000 31 66 165 426 434 983 564 948 35.000 12 11 8Non-Carbonate Hardness................ CaSO* 5 98 165 287 274 7 18 40 58 54 0 172 295 125 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) fiabilrill supply--New York City (6) Well Water--Maywood, Illinois-- (2) Swamp Water (Colored) Black Creek, Middleburg, Florida 2090 ft. (3) Niagara River (Filtered) Niagara Falla, New Yora ' (7) Well Water--Smithfield, Va.--330 ft. (4) Missouri River (Untreated) Average (8) Well Water--Rosewell; N. Mexico (5) Well Waters--Public Supply--Dayton, Ohio--30-60 ft. (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 t]tie 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 gje in terms of parts per million.* This is the approved standard terminology for reporting the results of mineral analyses.5 Values reported in the other terms commonly used may be converted into the standard form by using the factors listed in Table 2. Parte per are hereinafter abbreviated ppm. A part per million signifies a unit weight of mate rial per million unit weights of the solution. . Corrosion and Water Formed Deposits, Causes and Prevention 903 Table 2. Conversion Factors fob Water Analyses To Convert . Grains per U. S. gallon............ ............ .............. Grains per Imperial gallon.................................. . Grams per liter................................................... .... Mg per liter--...................................... ;.................... Into ppm ppm ppm ppm Multiply by ' 17 14a 1000 1 ' Data for dissolved gases or pH values have been omitted in Tabic 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 COs 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 Phyla Algae Fungi Table 3. Principal Slime Formers Rough Division op Phyla 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 (Phycomycetes) and the stalked fungi (Basidomy- cetes) rarely form slimes but their filaments may hold together the slimes of other organisms. 904 CHAPTER 42 1952 Guide Table 4. Plant Wateb Supplied Examination WATER SUPPLY-- 200 feet deep well--average water temperature 53 F-- 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. ANALYSIS REQUIRED-- ; MACROSCOPIC L4 MICROSCOPIC |V) ` BACTERIOLOGICAL L) ORGANIC CONTENT |VJ PROBLEM-- A 25-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-- Heavy brown flocculant material settles rapidly in clear water. pH--7.3 Odor--woody, mouldy. :' ' MICROSCOPIC ; EXAMINATION-- Inobganic Matebial--small amount white crystals! Amobphous Matebial--small amount--brown. Ibon Bacteria--profuse growth of crenothrix--(Photo usually included). . CULTURAL EXAMI- :. NATION-- . : TOTAL COUNT Saboubaud's Agab 1. Aerobic gram positive spore-forming rod with mucoid . sheaths. (Photo usually included). , 2. Short gram negative coccibacilli (Photo usually in cluded). 100,000 organism/cc. . . ORGANIC CONTENT (by WEIGHT, DRY BASIS)--60% DISCUSSION- 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. RECOM- .' MENDATIONS-- It is recommended that the water be treated at the suc tion side of the deep well pump with chlorine in quanti ties sufficient to maintain a free chlorine residual of 1.0 ppm at the discharge of the shell and tube cooler. 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 return water. . In the heating and ventilating field, the biological characteristics of condensates are likely to be of concern only where the condensate is used Cbrrosion and Water Formed Deposits, Causes and Prevention ' 905 As cooling water in recirculating systems. The deleterious gas contents of condensates. however, very often create serious cortosion troubles. ; The data in Table 5 typify the chemical composition of the atmosphere ih' rural and metroplitan areas, and of stack gases when various types of common' fuels are used. The curves in Fig; 1 disclose the solubility of the maj or deleterious gases present in such atmospheres in 'otherwise pure water, when the partial pressure of the gas is one pound per square inch absolute.' - ' " ' ' : V:: - ` 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 steams 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 of Diffebbnt Atmosphebes . Air Flub Gases Name of Gas Chemical Formula Rubai. % by Vol ume Partial Pres sure psia Metro politan - Partial %by Pres Vol - sure ume, peia Bitum. Coal Partial %by Pres Vol sure ume psia Fuel Oils Partial %by Pres Vol sure ume psia Natural Gas % by Vol ume Partial Pres sure psia Oxygen ...................... : o. Carbon Dioxide....... : CO Sulphur Dioxide___ SO* 21 3.143 21' : 3.143 ! 2. 0.299 0.03 0.004 . 0.06: 0.009 15 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 906 CHAPTER 42 1952 Guide I' ' '' ' - 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 907, _ 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. . . - . d. Substances, such as the polyphosphates, having the property of. inhibiting the precipitation of calcium carbonate from solutions supersaturated with it, may be added. ' ' 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. Fio. 1. Solubility op Gases at Pabtial PbessUBE op f 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,8 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 other elements, particularly sodium, the compounds of which are relatively soluble. Fio. 2. Solubility op Calcium Carbonate in Distilled Water Containing Carbon Dioxide (pH Values at Approximately 7S F) 1 ' Fig. 2 Adapted bom (l)Ind. & Eng. Chem, 20 (1B28) 1107--by Baylia. (2) JA.CS. GO (1929) 2088--Frear Johnson. . 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 little trouble with scale. However, in both once-through and closed recirculat ing systems, slimes may cause trouble. If there is some tendency for scaling, it may usually be prevented by the 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. 908 CHAPTER 42 I' Open Recirculating Systems . 1952 Guide : : 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 op Calcium Sulfate and op Calcium Carbonate 1 poh Comparison :' ' ' (CaCOt in Equilibrium with Normal COt Content of the Atmosphere) Fig. 3.Adapted from Bull. No. 16, Univ. of Mich. "Formation and Properties 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 practical method for minimizing sludge formation. This is . Corrosion and Water Formed Deposits, Causes and Prevention 909 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,12 and inorganic sulphates.13 - 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 mussels, 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. PIVOT LIN E CHI Ax PTER 4 2 &3 a~ ie--al. .3. ; S S 8 "8 S c" So -S3 ~.s 15 321 a ** S3 Ho Wa HoB=--* HSS4*r^*cs,j. as' TTTilTrUrsUssi s sinss 1|"I 1 I I I | I min|im|iwp} i | *|iUH'H1 PHTI'IV 1952 Guide *3- .in! g.9i * > o * o <t o O o * O n - - o' o 9* 9 O r* r* *> * o o 2 12 t% c* n o 5 ::! s .. . 8 3 o# i r, | 4 | "i,,,,i"nr ne o , i 'i 'i'in'i'ri,,"i'mi oooooo o o ' r o TP1 oo gM l-rm-r oo i111 rr oO* : o o o'I rn TT TT| I I M | I I I I | I M I | I I n ` o. o ^^ o n. !3 s f s3i5 oO . Corrosion and Water Formed Deposits, Causes and Prevention 911 While chlorine is the most generally used chemical, the use of others may occasionally prove to be more practicable. Choice of the chemical is conditioned largely by the design and operation of the system.. Open Recirculating Systems In spray ponds and cooling towers of the open type, light-loving algae growths are likely to cause blocking of 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- Table 6. 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 Tetracnloropnenate Pentachlorophenate Permanganate of Potash Blue Vitriol Gas Crystalline Briquettes Briquettes Briquettes Crystalline Crystalline 8 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 in general is subordinate to those mentioned. Dissolved oxygen, acid 912 CHAPTER 42 1952 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 . ! .' Where water from municipal supplies is used industrially in a closedsystem 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 cases the cost may be prohibitive. When the use of sodium sulphite or a comparable chemical for oxygen removal 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 tests16 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 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 systems, not previously , inhibited, about 500 ppm of sodium dichromate are usually maintained at the start: After two or three months, aind in new systems, a residual of . about 300 ppm of dichromate usually proves effective. When insufficient dichromate is employed, pitting is sometimes accelerated. Aeration does, not impair the efficiency of dichromates, but does deplete the caustic soda concentration. ! . In large industrial systems, the use of vacuum deaeration has been shown to be effective.1* 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. . Corrosion and Water Formed Deposits, Causes and Prevention' 913 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 . .1 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 914 CHAPTER 42 1952 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 suggested80 that 125.1b 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 op Sodium Bichromate to be Added to Maintain Initial Concentration . ' Specific Gravity of . Brine to be Strengthened 1.16 1.18 1.20 1.22 1.24 1.12 1.14 1.16 1.175 Lo Sodium Dichromate 1 . per 100 lb CaCls Added . .. 0.695 0.621 0.556 0.502 0.455 , . , - Lb of Sodium 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 50 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 915 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."' ' Design of Condensing Equipment. In the design of water heaters and comparable types of condensing equipment,88 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. Fio. 5. Relation of Htdbate/Cabbonate Content in Hard Boiler ' Water and CO in Steam at About 5. Psi Operating Pressure (AU 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 COs 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 COs 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,84 inadequate quantities may accelerate rather than decelerate corrosion on those surfaces not covered by the oil. Sodium silicate added to COs-bearing condensate has been shown to decrease, but not entirely prevent, corrosive action. It is not definite whether the protection afforded by silicate solutions is due to the establishment of a protective 916 CHAPTER 42 ; 1952 Guide i- ' - film on the. metal surface or to neutralization of the CO* by the alkali in the silicate solution. .: , : ..It has been postulated that ammonia,25 cyclohexylamine;?' ethylene . . diamine, and morpholine2.7 will retard corrosion of condensate lines. Tests with benzylamine havealso 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 COj 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 8CS8CMCR STtC NO Aata 1 1 i 60 GAY TEST 12 18 20 24 28 O 4 6 12 .16 20 24 28 O 4 8 12 16 20 24 28 32 38 40 AVERAGE penetration in INCHES PER TEAR X 1000 Fig. 6. COMPABATIVE CORROSION RESISTIVITY OP 10 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 reflect the corrosion resistance of the more commonly used metals to attack by condensate containing oxygen and COj. . .. In contemplating the use of a resistant metal, as a section of a conden 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 densates. .. . ATMOSPHERIC CORROSION Most of the problems originated by atmospheric corrosion occur in connection with the fire-side of boilers and furnaces (including their flues Corrosion and Water Formed Deposits, Causes and Prevention 917 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 . yirtually 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.31 Concrete linings for steel bunkers have also been ef fectively employed.82 . 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 steer 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.15). . - 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 the 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 918 CHAPTER 42 1952 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 copper- silicon alloys will resist corrosion and may, at times, be used to advantage. However,34 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 hot be embedded directly in cinders or in tidal marshes where it may be subjected to attack by sulfur compounds. Lead33 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 919 maintain them by recoating when necessary. Buried steel pipe lines' have been protected against corrosion with considerable success by the use of .very thick bituminous coatings applied in molten condition. The.best results are obtained by applying the bituminous coatings over a standard priming coat such as red lead or a 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 bareanodic 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 hairing 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.33 . 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 reported37 to produce dermatitis. Chrom- itch is not uncommon among workers handling chromates. The amines are said to be absorbed through the skin.38 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 in 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- 920 CHAPTER 42 1952 Guide -yided, and a shower head or its equivalent .provided at or very, near the point.where the chemicals are mixed. Chemicals should always be washed from the-shin urith.lhrge volumes of water. - . .. . . ;,,For the handling of chlorine and chlorinators, the U. S. Public Health Service29 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 interVals and kept in serviceable condition. Note:--All-purpose masks offer adequate protection only when the concentration of acid gases does not exceed two percentsee 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: "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,nr 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 aU public water supplies in the United States.42 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 921 Table 8. Recommended Maximum Allowable Content in Wateb; Supply* , . .Max . - .Substance ' CONCENTRATION, Substance ppm Max Concentration, ' PP?n . .' Copper.:.................... lion & Manganese (Total). Magnesium.................. ............ Zinc............................................ Lead............................ .... . Fluorine............................... .... U. S. Public Health Service. 3.0 0.3 125.0 . 15.0 0.1 1.0 Phenols (Total)............... :.. Poly-phosphate of Sodium;. pH Value @ 25C................... . , *' ' ' 005 0.05 0.001 ,10 0 .10.6 ! 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-rsiphoned 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 nr the water supply, the feeding device shall automatically cease operating." . REFERENCES j : I Annual Report (1947) Committee D-19 (American Society for Testing Materials), , 2 Corrosion Handbook, edited by H. H. Uhlig (John Wiley & Sons, p. 27).: Discussion, Corrosion and Material Protection, May 1945, p. 2. . 4 Round-Table Discussion on Organizing the Classification of Industrial Waters, b^W. C^Schroeder (Proceedings, American Society for Testing Materials; Vol: 44 Typical Water Analyses for Classification With Reference to Industrial-Use, by W. D. Collins (Proceedings, American Society for Testing Materials, Vol. 44, 1944, p. 1057). .. . . . . ... . ` A.S.T.M. Standard D-596--41 (American Society for Testing Materials)-. . - . 7 Discussion on Preventing Solution of COj in Condensates, by E. W. Guernsey (A.S.H.V.E. Transactions, Vol, 51, 1945, p.,69). . -. - .. . Studies of the Mechanism of Solution of COi in Condensates Formed in Steam Heating Systems of Buildings, by L. F. Collins (A.S.H.V.E. Tbansactions, Vol; 51, 1945, p. 39). . .. . ' .' The Analytical Control of Anti-Corrosion Water. Treatment, by W. F. Langelier (Journal, American Water Works Association, Vol. 28, 1936, p. 1500). . , 10 Surface-Active Properties of Hexametaphosphate, by G. B. Hatch and Owen Rice (Industrial and Engineering Chemistry, Vol. 31, 1939, p. 51). . II Slime Control in Cooling Equipment with Phenol Derivatives, by J. A. Holmes (Pj-weedings, Annual Water Conference, Engineers' Society of Western Pennsylvania, 11 Tuberculation of Mains as Affected by Bacteria, by H. G. Reddick and S. E. Linderman (Journal, New England Water Works Asscoiation, Vol. 46, 1932, No. 42). ** Microbiological Anaerobic Corrosion of Steel Pipe Lines, by R. F. Hadley (The Oil and Gas Journal, September, 1939). 14 Tests of Corrosion Inhibitors for Water Treatment in Air Conditioning Equip- 922 CHAPTER 42 . 1952 Guide 'ment, by James H. Wilson and E. C. Groesback (Research Paper 1305, 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). ' . Cold Water Vacuum Deaeration, by S. T. Powell (Proceedings, Water Confer ence, Engineers' Society of Western Pennsylvania, 1945, p. 51). -. Corrosion--Causes and Prevention, by F. N. Speller (McGraw-Hill Book Co., 1951, pp. 805, 905, 910 and 912) . . u Corrosion Control with Threshold Treatment, by G. B. Hatch and Owen Rice (Industrial and Engineering Chemistry, Vol. 32, 1940, p. 1572). " - i Refrigeration Data Book (American Society of Refrigerating Engineers, 1936, p. 404). ,.o Engineering Problems of Water Treatment, by L. F. Collins (Power Plant Engineering, Vol. 50, July 1946, p. 78-81,120). 11 See p. 470 of Reference 18. . . " Studies in The Detroit Edison Co. (Unpublished). , . " 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). * Corrosion in Steam Heating Systems, by Leo F. Collins and Everette L. Hender son (Beating, Piping and Air Conditioning, October 1939, p. 620). U. S. Patent 1,395,730. U. S. Patent 2,053,024. ,' . 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). . i 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). . " Rubber Linings and Coatings, by J. J. McNeil (Corrosion and Material Pro tection, March-April, 1947). . .. ** Protection of Steel Bins from Corrosion, by J. V. Schaefer (Power Plant Engi neering, Vol. 26, 1922, p. 632). . " Some Notes on Corrosion of Cast-Iron Sectional Boilers, by E. R. Walters {The Institution of Healing and Ventilating Engineers, Preprint, 1944). . ' * See p. 67 of Reference 2. " Soil Corrosion Studies, 1941 by K. H. Logan and M. Romanoff {National Bu reau of Standards Journal of Research, Vol. 33, 1944, p. 145). " Cathodic Protection of Steel Equipment Submerged in Water, by L. P: Sudrabin (Proceedings, Water Conference, Engineers' Society of Western Pennsylvania, 1944). n a, discussion by D. W. Haering (See p. 66 of Reference 11). a Cyclohexylamine and Dicyclohexylamine, by T. S. Carswell and H. L. Morrill {Industrial and Engineering Chemistry, Vol. 29, 1937, p. 1247). ' 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. . * 41 Official Plumbing Code of the City of Detroit, Article V. "Private Communication from H. S. Jordan, A.W.W.A. CHAPTER 43 OWNING AND OPERATING COSTS Fixed Charges: Amortization, Interest, Taxes, Insurance, Rent; Maintenance Costs;' Service Costs: Operating Refrigerating Equipment, Condenser Water, Heating THE purpose of this chapter is to discuss owning and operating costs of heating, ventilating, and air conditioning systems. The discussion will dwell particularly on air conditioning systems, as most owners or prospec tive purchasers will be interested in comparing the owning and operating costs with the. possible investment return due to increased patronage, im proved efficiency of employees, or improvement and maintenance of quality in a manufactured product. Owning and Operating Costs may be grouped under three headings: (1) Fixed Charges, (2) Maintenance Costs, and (3) Service Costs. FIXED CHARGES Fixed Charges, which are the cost of owning the system, include: (1) Amortization, (2) Interest, (3) Taxes, (4) Insurance, and (5) Rent. Amortization , Amortization cost will depend on: (1) the total first cost, and (2) the amortization period. . The total first cost of an installation is the actual dollar outlay or capital expenditure required to buy and install the air conditioning, or heating and ventilating system ready for operation. It can be divided into two parts: (a) the first cost of the air conditioning or heating and ventilating system-itself, and (b) other first costs incurred because of the installation of the air conditioning or heating and ventilating system. The first cost of air conditioning or heating and ventilating systems in cludes 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. 7. Insulation of "pipes, ducts and equipment. ." The best procedure for establishing the first cost of any system is to. first determine the heating and cooling load and then, after a thorough engi neering study, select the type of1 system. The installed cost of a system will vary between wide limits depending upon the type of equipment selected, the design of the distribution system, equipment and labor costs in the locality, etc. An approximate cost, within 10 percent, may then be quickly determined for a selected design in a given locality by adding 923 . . " :- E q u ip m e n t , T e m p e b a t u b e C o n tbo ls, e tc .* T a b l e I . . C o s t D o l l a b s p e b T o n p o b a -C o m p l e t e S y s t e m , I n c l u d in g H e a t in g a n d C o o l in g C o; il s . F a n , D u c t s , R e f b ig e b a t io n ,' CHAPTER 43 Sag eo oog 3 ^(glOo* ggsHo , 5 > a > g5 as 52.00 50.00 48.00 46.00. 44.00 /42.00 40.00 1952 Guide 1.55 190.00 1.43 165.00 " 1.38 120.00 1.33 ' " 90.00 1.30: 60.00 1. 28 . 1.25 1.23 1.17. 1.14 3 dBBc " O 'Is ' oCoO. - &2 ' *! dcfHe ;&v cCq 0ioi-r>; :0<355- 0ic>0eoi o0o0. ^00' <t--o - t'-'<--. c<i CQ ` ci--. in -< T* rH fH ' , .4 . o HZo faHtcs ..0, 0-.0 0 Q -Q :o .Os,0/. = ttro*.rOcocOoos^cootOOO*'c^-<*o,cOoO5owNtoooO.t.oo00 19,350 35,700 51-000 66.400 ' 97.400 128,200 ' 156,800 183,600 234.000 284.000 13,100 24,500 35,700 46.000 68,200 90.000 110,000 129.000 168.000 205,000 Aib Han- DUNG Equipment 00 HOiK 0' Bo* sO 3HO H A SB CO ' -lag - 6,250 . 11,200 15,900 20,400 29,200 . 38,200 . 46,800 54,600 66,000. 79,000 E walo Ra.Hf^fl S30.H0. . s ' m 8 -PdB 0So '- . & oto ooo tOoi.-Om io-- oo oooo . ooo oo 0c0q , H . . .- 1 a3sB*&*5hb=o , Oic4A;C^c*Nqciq^-t<5O3oHNo_oNHoN.oH Wof-HoOof-4 tOo^ . HO BSE3-. 12.500 26,000 37.500 50.000 75.000 100;000 125.000 150.000 .200,000 250.000 ; ' B 3 eo s Q& .. E g- 1" <ta Cl <& S" fe - as - 8,333 16,666 25.000 33.332 50.000 66,664 83.333 100,000 133,328 166,666 sJas-8 Mi 3o"|-S 9 8 1 o - ' |8 J ft 5 a s-s | H I |1 | ps . ; Owning and Operating Costs -- , .. -925 the estimated unit costs of the component, parts of the system. A rea sonably precise estimate of the cost.of the components: may, be, obtained from cost records of recent installations of a comparable design, or may be obtained from manufacturers nr contractors. , Table 2. Pbobable Useful Life of. Equipment* ''lajiiN YiABSi,: 1. Heat Pboducing Equipment ' (a) Boilers................. ................................................................................ (5) Stokers and burners.................................................................. ...... 20 20 2. Heat Distbibuting Equipment : (a) Piping--copper....................................................................... .......... (o) Piping--iron.......... ............................................................................ (c) Radiation--concealed..................................................................... (d) Radiation--direct.................... ,.......................................... .. (e) Valves and specialties.................................................................... same as bldg. 20 25 25 3. Aib Handling Equipment -- (a) Filters--automatic___ ___:..........:............................................ '.. (&) Heating and cooling coils............................................. (c) Spray humidifiers and dehumidifiers........................................ : (d) Fans.................................................... .................. ...........i:;.. . (e) Air conditioning units...................... .............................................. (f) Motors................................................................................................... (g') Electrical starting equipment..................................................... (A) Pneumatic contr(H systems.......................................................... () Electric control systems.................. .............................................. : 20 20 10 15 10 20 20 15 15 . :,:! - " : ! ,: . 4. Aib Distbibuting Equipment . (a) Ductwork......... :................................................................................ (6) Outlets, grilles.................... .............................................................. (c) Duct insulation........ ........................................................................ same as bldg. 20 - 15, . . 5. Refrigerating Equipment (a) Centrifugal refrigerating machines............................................ (6) Reciprocating refrigerating machines........................ ,. . (c).-Motors and starters..........~.................................................... .. (d) Piping--copper........................................................... ...................... (e) Piping--steel........................... .......................................................... "' 20 . 20 20 20 20 ' 20., . : . 6.. Wateb Saving Devices (a) Evaporative condensers................................................................. (b). Cooling towers...................................................... ............................ 15 15 * Taken from U. S. Bureau ofInternal Revenue Schedule of, Probable Useful life, revised 1042. . In Table 1 an attempt has been made to give approximate averages of the cost of air conditioning systems where the refrigeration .requirement is one ton for every 333 sq ft of floor area, and where the air quantity" to be distributed is cfm per sq ft of floor area. This table, should be used with caution, as the floor area per ton of refrigeration and the cfm per square foot of floor area may vary between wide limits. Other first costs, incurred because of the installation of the air condition- 926 / Cs. HAPTER 43 1952/' Guide -mg or heating-and ventilating system, include costs of electrical work, plumbing, miscellaneous' piping, building alterations, cutting, patching, furring in of ducts or pipes, foundations, structural supports, remodeling or redecorating after installation, consulting engineer's fees, licenses, per mits, etc. These vary so widely that no approximations are possible, and each case must be considered alone. - The length of the amortization 'period to be used depends upon: the type 'and remaining life of the building or space for which the system is to be used; the type of equipment to be employed as a part of the system; the character of the business; and the lease or ownership conditions. . Table 3. Owning and Operating Cost First Cost Annual Service Cost Cost of mechanical system................ Other costs............................................. ___ FiratC^t^FC)^Tgtal....... Annual Fixed Charges Amortization--Depreciation period Y years.............................................. Interest rate 1%................ ; ............ -Amortisation and Depreciation FC _ Y "............................................ Y 4- 1 Interest: --X / =....... . ......... Taxes.................................................... Insurance.......................................... -Rent....................................................... Annual Fixed Charges: Total) Annual Maintenance Costs Replacement or servicing of air filters................................ .................. Outside Maintenance service............. Water Treatment................................ . Lubricating oil and grease--;......... Painting for corrosion protection or other purposes................................. Replacement of worn parts.............. Refrigerant........................................... Wages of engineer or operator......... Annual Maintenance Cost-- TOTAL...................................... Electric Power Costs - Fans.....................................................-- Pumps--Chilled water................... -- Pumps--Condenser water...............-- Pumps--Well water...........................-- Cooling tower fans............... -- Cooling tower pumps...................... -- Refrigeration machines.......1------- -- Miscellaneous or other............ '.... Gas........................................................... -- Coal................... t Oil--for boilere or Deisel engines... -- Steam ' For Direct Heating............... -- For Ventilation--preheaters......... - For Ventilation--reheaters............- For Turbine driven equipment... - For Engine driven equipment-- - Sewers ', Charges for discharging water - into public drainage systems... - Condenser water...................... - Annual Service Costs-- TOTAL............................................ - Summary Annual Fixed Charges....................... Annual Service Costs........................ Annual Maintenance Costs............. Annual Owning and Operating Costa--TOTAL. Depreciation, due to deterioration and obsolescence, must also be con sidered in arriving at the amortization period. Deterioration and mainte nance generally go hand in hand. If a long depreciation period is to be used, the item for maintenance, repair and replacement of wearing parts must be greater than for a short depreciation period. An approximation of the useful life of various items of equipment and parts of systems is shown in Table 2. It should be noted that if an appro priate maintenance item is hot established, the rate of equipment deteriora tion may be increased substantially. Interest The interest chargeable may be based on the average money rate for the period in which the first cost of the equipment will be amortized. Owning and Operating Costs 927 Some accountants do. not include interest in the annual fixed, charges,-as they consider it a negligible item. : . . The formulas for computing interest and amortization are given in Table 3. This table will also serve as a check list of the various compo nents to be considered in determining owning and operating costs. - Taxes ' ... . . ... . . . '..... The taxes chargeable will be the proportion of property tax caused by the increased valuation , of the property,due .to air conditioning. . Insurance The rate for insurance may vary considerably depending on the type of structure in which the equipment is located and upon other governing factors. A rate of about $0.60 per $1,000 may be considered as being representative of normal installations. Table 4. Approximate Maintenance Cost for.Largb Air Conditioning Installations, Usino High Quality Equipment , - Dollars per Ton per Yea b Repairs for refrigeration machinery............................. .. Refrigerant................................................ ......................... .................. Oil and grease....................................................................i.................. ' Painting (Water boxes and dehumidifieiB)................................. Filters, clean and re-oil 4 times per year................. .............. Controls, outside service......................... ........................................... Cleaning air conditioners................................. ..............;................ 0.40 0.11 ,0.40 1.38 0.24' 1.19 Rent 5 ' . ; ;/ " If the equipment under consideration is to be located in rented or leased quarters, it may be necessary to include an item for space rental. MAINTENANCE COSTS Maintenance costs include replacement: parts and the labor required for making repairs, replacing parts, cleaning, painting, etc. It should be noted that major overhauling or complete-replacement may restore the capital value of certain items of equipment, and in such cases the costs incurred may not necessarily be charged as maintenance costs. Generally, routine labor requirements will be the function of an operating engineer or staff, and the responsibility of this group may extend beyond the equipment being discussed here; hence, it is important to include only an equitable share of the time of this group. Extraordinary repairs involving special machinery will usually be covered by contract with equipment service divi sions, and should be accounted for on that basis. ' - Many of the items included in maintenance costs are' highly variable and depend on the type and quality of the purchased equipment. For 928 CHAPTER 43 1952 Guide i ' -large air conditioning installations,, using high quality equipment, some approximate costs per ton are given in Table 4. SERVICE COSTS Service 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: . .. i 0.746(bhp)//K annual'power cost = --:-------------- (1) where bhp = brake horsepower. H = annual operating hours. B = power rate, dollars per/kwhr. tl = 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 largely the demand charge which determines the proper value of R to use in Equation 1. '' Operating Refrigerating Equipment In an air conditioning system the refrigerating equipment is usually the largest power consuming item to be considered. Also, the prediction of operating cost is more difficult 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 cooling for the period of May 15th to Octo ber 15th. This table was calculated from the following equation: //. = m(b + cf) . i (2) where .. . - .. Hi == equivalent full load operating, hours of refrigeration equipment used for . summer cooling during period May 15 to October 15. .. m = total hours during period May; 15 to October 15 that the establishment' is i. open for business. ... . . b = fraction of maximum load from internal heat under average operating con . ditions. . . .- . c = fraction:of.maximum load which is due to external sources at maximum ! : : design conditions. . .. ; : / = ratio of the number of hours for a particular city, when the outside wet-bulb ; I : exceeds 65 F, during the period June 1 to October ! to the total, number of hours during that same period. Total hours are assumed, as 8 hr per day .. .. . period for barber shops, department stores, funeral parlors, offices, short : , | hour restaurants, and specialty shops, and 12 hr per day .period for drug stores, long hour restaurants, and theaters. - - Owning,and Operating Costs 929 It should be pointed out that certain southern cities may have seasons longer than the 5-month period indicated in Table 5. If it is desired to consider a longer season of operation, the ratio of full load operating hours to hours open for business is smaller; in other words, the refrigeration loadfactor 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: ' where 0.746 (bhp,) TH. R season power costs = v. (3) brake horsepower per ton (see Fig. 1) for average load during period. (Due allowance should be made for poorer compressor efficiency at light load.) tons of refrigeration at maximum design load. . equivalent full load refrigeration operating hours (Table 5). - power cost, dollars per kwhr, including demand and energy charges, 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 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 pm--' 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 = 0.060 aTH.C 1. .(4) where B = cost of water for refrigeration during period, dollars. o = average gallons per minute (ton). T = tons of refrigeration at maximum design load. Ht = equivalent full load refrigeration operating hours (Table 5). C = water cost, dollars per 1000 gal. ' The average gallons per minute per ton must take into account the variable water temperature. When well water is used as a source, and CHAPTER 43 /- swnp: 1952 Guide Owning and Operating Costs ' 931 entering and leaving temperatures are considered constant, the average gallons per'minute per ton obviousfy are equal to the design gallons per minute per ton. However, when the source is river or lake water, its max imum seasonal temperature will generally be reached at the same time that the refrigeration load factor is highest. The average gallons per minute per ton shotdd be calculated from known or estimated water temperatures; be cause they vary through the season.' Maximum water main temperatures are given in Chapter 34, but'should always be verified locally. ' In lieii of this tedious work, the average gallon per minute per ton may be taken as 80 percent of design gallons per minute per. ton with reasonable accuracy, CONDENSER TEMPERATURE, FAHRENHEIT DECREES f Fig. 1. Typical Brake Horse Power Requirements for Refrigeration* * Values given are representative of "F-12" reciprocating machines of about 25 tons capacity in air con ditioning applications. Requirements of smaller machines are usually higher, and for larger mnchinpa may be lower. Values shown are for liquid refrigerant at condenser temperature (no subcooling). Suboooling of the liquid may decrease these values approximately 0.3 percent to 0j5 percent for each Fahrenheit degree the liquid temperature is lowered. for the condition of variable temperature of entering water obtained from rivers and lakes. When cooling towers or evaporative condensers are used, the windage and evaporation losses are usually between 2 percent and 3 percent of the water circulated. Heating ' The method of estimating fuel consumption to balance the building heat loss is given in Chapter 17. 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, Ike 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- di 932 CHAPTER 43 1952; Guide ifying, must.not; be neglected, when this'.feature is included equipment. , .. i .. ; ... the ^ ' . ! BIBLIOGRAPHY .Modern Air,Conditioning,Heating and Ventilating, by W. H. Carrier, R. E. Cherne,'and.^lX Grant-^liapiter IV (Pitman Ptiblishing Corp., 1910). i( , Predicting .(Operating -Hours of Refrigeration Equipment Used in Air. Condition- iifg;:by W. A.;'Grant'(Re}rigeraling`Engineering, 3\uy,1941). ` ' /. ' Cost of Operation of Refrigeration Used for Air Conditioning, by R E.` Cherne ' (Refrigerating`Engineering, December, 1943)/>> ' ! .' t : ' u> . CHAPTER 44 INDUSTRIAL AIR CONDITIONING General Requirements for Manufacture, Processing and Preservation; Design Con ditions and Application Data; Classification of Problems; Moisture Content and Regain; Conditioning and Drying; Chemical and Biochemical Reactions; . Crystallization; Control for Machining, Polishing, and for Static Eleo- tricity Elimination; Laboratory Conditions; Calculations; Safe1' . guarding Health and Maintaining Safety; Contaminant Con trol; Dilution Systems for Contaminants; Heat Storage; . ... Radiation; 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, and commodities; and (2) maintaining the health, safety and, efficiency of workers. This chapter includes 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 is a wide variance between manufacturers' requirements, depending on results desired, experience, and cost considerations. V CLASSIFICATION OF PROBLEMS.................. In general, any industrial air conditioning problem in processing may be 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 crystallization. 1 6. Control of temperature for close tolerance machining and grinding. 933 934 CHAPTER 44 1952 Guide . Table 1. Temperatures and Humidities Applicable to Industrial Air . .Conditioning* ' Process . , * f Temp. F j R.H. % BAKERY , . Bread oven............................... ..................................................... . : 75-80 ; - 75-80 92-06 375-450 ' /. ; 40-50 70-75 80-85 Bread cooler (room.or tunnel) Vacuum 28.6 in.'............. . ' '' . , 7-7.6 . .. 40-45 .. 75-80 70-75 . 95-110 . 60-65 60-65 . . : . 8O-85. 65-70 -65 50 60-65 Fresh ingredients, storage.......................................... .............. 70 30-45 65-80 45-70 80 . 32-35 .. 70-80': 55-65 80-85 60-es 55-65 35 ' . 40^50 f . . METHODS OF MIXER COOLING ` 1. 35-40 F water.circulated through mixer jacket. '; 2.15-25 F brine. . .. 3. Direct expansion, refrigerant circulated through mixer jacket. 4. Cracked ice added todough in mixer. . - 5. Cold air introduced into mixer during mixing process. 6. Cooled agitators are used in mixers. ` . - - ` - . ... -. , '' ' . .. MIXER LOAD CALCULATIONS'V ... !" Refrigeration is required to remove: excess ingredient, if any;,'heat generated by the beating and mixing of dough; heat in miTM1 body; heat of hydration of flour and water; and heat absorbed by mixer from atmosphere during mixing process. .. ' , , . t Additional factora are the design and speed of mixer, consistency, kind and mass of dough. . Data Used in Calculations: ' ... '' 1 bb!. flour ** 200 lb ` ';' . Heat of hydration *= 6.5 Btu per lb. of flour . " - . Specific heat of flour = 0.42 Btu per lb ` Water is 65% of weight of flour Flour is 65% of batch ,- ... Sponge is 60% of batch . -. , Total motor output is converted to heat in the mixer. ' 1 ,: . `` .' ! . . . . ' ` . In fermenting robins recent practice is to use direct radiation for heating, atomising sprays for humidify* ing, and gravity convection oooling surfaces lor temperature reduction and debumidifying thereby eliminat ing objectionable air currents. ..... . ' Proof box and bread'cooler conditions vary slightly for dark bread. ' " ` Cakes are sterilised by ultra-violet rays before wrapping. - ' ` ' - - - - ': . Process ' BANANAS . Temp.F ' : 68 . 60. , 54 to 56 ' ; R.H. % . . 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 68 F-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 is to be moved. : . - < .- ' ' i - ` Typical refrigeration load for ripening room per carlot, with an 85 F ambient temperature: Insulation 4b electric load . -- 0.4 ton ' Lave load = 0.9 ton . Pull download (from 68 F to 60 F) 1.6 ton . ; Minimum carlot--20,000 lb which represents about 300 stems. ' . Since 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.Air Conditioning 935 , 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). ' '' . *1 Approximate rate of evolution of heat by bananas when stored at temperatures indicated: " ' Bananas at 54 F .= 3,300 Btu.(per ton) (24 hr). green at 68 F = 8,360 Btu (per ton) (24 hr). ' turning at 68 F = 9,240 Btu (per ton) (24`hr). ripening at 68 F 8,360 Btu (per ton) (24 hr). - ` . .' ' ' .- ' Room BREWING Temp. F; - R.H. % Ale...................... /............................................................ * If wooden tankage is used, otherwise humidity con trolled to prevent condensation on walls and ceiling. 30 to 32 32 to 34 40 to 46 32 to 35 55 to 62 CO ii , ` 75 min.* 75 min.* . * 75 min.* 75 min.* 75 Wort cooled to 47 F for lager, 54 to 59 F for ale, by evaporative oooling or use of double pipe or plate type ooolers with counter flow of cooling medium. - Fermentation produces 250 Btu per lb of sugar fermented. Lager fermented five days at 55 to 00 F, ale at 68 to 75 F, then cooled to storage temperature. -- . Bottled beer pasteurized by heating to 140 F in twenty minutes, maintaining temperature for aighteen minutes, then cooling to 80 F in twenty minutes. Canned beer requires one-third timo, Cold water, brine, direct expansion ammonia or propylene-glycol and water solutions may be used as the cooling medium. . ,. . Process . : I . Temp.F . 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 -I . R.H. % 40 to 50 50 to 55 55 to 60 A0 13 40 to 50 55 45 40 to 50 Tunnel discharge room requires a dew point lower than the temperature of the product leaving the tunnel. ^ During the summer months the product is usually held in the tempering room for 24 hours prior to ship- Recovery of sugar fly in coating kettle rooms is accomplished with the use of cyclone type dust collecting uevices. 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 100,1b of 90 F chooolate per (worker) (hr). . Specific heat of chooolate = 0.30 to 0.56 Btu per Gb)(F deg). Latent heat of fusion = 34 to 40 Btu per. (lb) (F deg). Freezing point = . ' ' .. ' , ' ' Sweet milk chocolate = 86 F. ` '". . ' Dark chooolate 90 to 92 F. - .. .. '` \ '. . Process I Temp.F . CANDY (HARD) Manufacturing .. Tunnel ...................................................................... Peeking................................ Storage....... . Tempering = (Ventilation only) - 75 to 80 75 to 80 55 65 to 75 65 to 75 B.H.% 30 to 40 40 to 45 40 to 45 45 to 50 <936 CHAPTER 44 )^ ^ * 1952 Guide /' i - Table 1.' 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 120io 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 theroom. .. .' . , ' 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.- . . . !t Filtration of air is required. . - ' Process ' Temp. F CHEWING GUM .. 77 68 72 74 74 ' ; R.H. % 33 63 53 47 58 Process F R.H. . CERAMICS . Molding room................................................................................ Clay storage.......................................... ............... ............... Decalcoznania production'.-......................................... Decorating room------- .................................................................. . 110 to 150 . . .. 80 . - - 60 to 80 ; '75 to 80 - 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 essentia], and the dust count must be held down to four million particles per cubic foot due to the danger of silicosis. . .. . Process ' CEREAL Packaging...................................................................................... Temp. F ? 75-80 R.H.% 45-50 ; Process ' CITRUS FRUIT Temp. F ' r.h.% 1 ; . ` Prior to transcontinental shipment 58 . 60 84 to 88 86 to 88 .. Careful consideration must be given to air volumes, air temperatures, humidity, ventilation and dis tribution. '1 " In regions where end rot is prevalent, it may be necessary to store grapefruit at temperatures of 32 to 34 F for a period not exceeding Bix weeks. " 1 ;' Lemon and grapefruit storage requires ah air conditioning system to (1) maintain a constant temperature, (2) maintain a nigh relative humidity, (3) ventilate to maintain 0.1% CO* content, (4) obtain uniform air 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 Per (ton) (24 hb) ' Lemons Grapefruit 580 810 . 2070 6200 460 1070 . * 2770 4180 - 1 - Industrial Air Conditioning 937 Table 1. Temperatures and Humidities.Applicable to Industrial Air Conditioning--(Continued) ' CITRUS FRUIT (Continued) - Approximately 10 percent of the cooling load is considered as latent heat load. . . In a conventional system the air required-is one cfm-'per storage box or 650 cfm per carload, resulting in a small temperature rise in the supply, air making possible the required high humidities. . - In a combination system the air required is one cfm per sq ft of floor area or 300 cfm per carlot with the addition of auxiliary humidifying nozzles to maintain the required high humidities. : - - Installation of metal ducts is required. Ductwork made of insulation board is sometimes preferred;1 Process Temp. F R.H.%............ DISTILLING : . j; Storage: . . 60 ' 35 to 40 ` : 32 to 34 65 to 72 - 50 td 60 Mashing done at 150 to 155 F; then oooled to 64 to 68 F. * Yeast culture fermented at 170 F, then cooled to 70 to 72 F. ' ' Yeast propagated at 150 to 154 F. . .. . ... . . . . Mash heated to 165 F and then cooled to 80 F,.then pitched with yeast and fermented at maximum tem perature of 85 F. ' ` '' - - .. Cooling for various distilling processes normally accomplished by use of river or well water depending on temperatures and availability. . . .. Low humidity and dust control important where grains are ground. . Viscous filters preferred as mold spores and bacteria are trapped in the viscous film, preventing propaga tion. Process j Temp. F . Electronics and X-Ray: . . ELECTRICAL PRODUCTS ... R.H. % - '' . '.r- Electrical Instruments: , Small Mechanisms: 8witohgear: , Water wheel generators: Rectifiers: '~ Dust control is essential in these processes '.' . : ; 70 -76 * 76 ' 72 74 to 76 73 ` 73 73 75 68 76 70 ' 74 - ,r ' 50 to 55 50 to 55 : 40 to 45 60 to 63 50 50 50 65 to 70 , 30 to 40 Process Temp. F R.H. % FLOOR COVERING Linoleum: 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. - : Precise control of temperature and humidity is. required for mechanical oxidizing of linseed oil. The rate of flow and the temperature of cooling water in the jacket surrounding the tank must be controlled. - Air filtration is recommended for the stoving process. 938 CHAPTER 44 1952 Guide / Table 1. Temperatures and Humidities Applicable to Industrial Aib Conditioning--(Continued) Pbocess .. | Temp/ F Mold making: ' * Winter design temp. foundries : 60 to 70 60 to 70 ' 55 to 65 40 40 to 50 55 to 65 The charging room is usually unheated. ' In oore making fume exhaust hoods are required for oven and for cooling areas adjacent to ovens. In mold making provide hoods at transfer points with wet collector dust removal system. Use 600 to 800 cfm per hood. . * Pouring rooms require two-speed powered roof ventilators. Design for minimum of two cfm per sq ft floor area at low speed. Shieldingis required to oontrol radiation from hot surfaces. Proper introduction of air will minimise preheat requirements. In shakeout room provide hoods with wet oollector dust removal system. - Exhaust 400 to 500 cfm per sq ft grate area. Roof ventilators are generally .not effective. . In cleaning room provide hoods for grinders and cleaning equipment with dry cyclones or bag type col lectors. .. .. '" Winter ventilation (preheated) is require! to the extent of replacing exhausted air. Summer ventilation 8 usually supplemented by use of pedestal fans. ' .' Spot coolers are sometimes us^d in larger installations. ' .. ' Pbocess FUR Temp. P R.H. % 110 18 to 20 40 to 50 55 to 65 Shock treatment, for eradication of any insect infestations, requires the lowering of the temperature to 18-20 F for 3 to 4 days; then raising it to 60-70 F for 2 dayB, then lowering it onoe again to l8-20 degrees for 2 days and raising it to the storage temperature. ' -1 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 Temp. F R.H. % Drying: Vegetable tanned........... ................ :........................................ Chrome tanned........................................................................ Storage.................................................... -...................................... 70 120 50-60 75 45 40-60 After leather is moistened in preparation for rolling and stretching, it is placed in an atmosphere held at room 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. ` Temp. F R.H. % LENSES (OPTICAL) Fusing.... Grinding. The air must be free of dust and temperature held constant. ' ' To acquire desired cleanliness of air a combination of impingement and electrostatic filters are used Dust collectors are required for grinding operations. ' 1- Industrial Air-Conditioning 939 Table 1. Tempebatubes and Humidities Applicable to Industbial Aib Conditioning--(Continued) ' Rooms Temp. F . LIBRARIES AND MUSEUMS R.H. % 70-80 70-80 40-50 . 40-50 Spray type dehumidifiers used to eliminate SO*. Water treatment is essential to maintain between 8.5 and 9.0 pH. -. Reheat is usually needed far refrigeration cycle due to the low 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 where leakage can cause damage. . Check Figures for Cooling Estimates: Low 40 20 30 0:73 0.12 0.92 Medium - High , 60 80 ' 1 35 ' - 45 - ` 51 75 0.83 0.90 0.23 0.40 1.60 . . 2.10 . MALTING (BREWING) Steeped 24to72hrin45to65F water. Germinated six days at 55 to.75 F. . ' Kilned at temperatures of 120 to 175 F. . MALTING (DISTILLING) Germinated twenty dayB at 63 F. . .... .... . Germination produces total heat of 16,000 Btu/bushel at varying rate depending upon grain and process. - Pbocess Temp. F: . RM.% . . . ` *' MATCHES . .... 72 to 74 . 70 to 75 60 to 62 ' 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. . Pbocess . ,,. Temp. F R.H. % MUSHROOMS Sweating-out period Spawn added........... Growing period........ Storage................. .. 120 to >140 60 to 75 48 to 60 32 to 35 nearly sat. moderate 80 to 85 As spawn startB to Stow, it is necessary to abruptly cool the mushroom house by 15 deg in a 12 hr period (approx.). Usually, this is the controlling factor in selection of refrigeration equipment, nnlejw 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. Visoous filters are preferred, as mold spores are trapped in the viscous film. Odorless oil should be used; * Heat of emission is 4 Btu per (hr)(pq ft of growing surface). . 940 Table 1. CHAPTER 44 i 1952 Guide Temperatures and . Humidities: Applicable toIndustrial Air Conditioning--(Continued) Process Temp. F PAINT APPLICATION R.H. % Lacquers: Oil Painte . .. 70-90 180-300 75 60 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 or Process Temp. F PHARMACEUTICAL R.H. % 80 90 75 to 80 70 ' 80 78 to 80 80 78 ' 75 ' 80 Biological manufacturing.......................................................... . . 80 Laver extracts................................................. . 70 to 80 . 74 to 78 75 to SO ., 75 to 78 : : ' *' ' -' 30 to 35 35 35 30 30 to 50 40 ' 5 to 10 35 ' 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 pier cu ft. Various kinds of gelatin require different temperatures. ' Penicillin incubation process requires, .holding temperature within i deg F, with temperatures and hu midity rigidly controlled during all manufacturing phases. `` " ' Ampule filling requires a 20 percent relative humidity when especially fine powders aroused.: Uncoated tablet manufacturing requires accurate control of temperature and relative humidity, since low relative humidity causes formation of a hard outer layer, and high relative humidity retards drying at the proper rate. '' Liver extracts 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. .r Sterile conditions are essential in many pharmaceutical processes. Provide suitable air exhaust to re move surplus material from tablet compressing machine. - Air filtration is generally required, with positive air filtration in some areas. . Animal Rooms in Pharmaceutical Laboratories ' In the following tabulation each of the items mentioned is equivalent in metabolism to one man: Quantity 6n7o2 73 7210 16 . .16 5 .. Animal White Mice Rats Rats i:- ' Guinea Pigs Rabbits Cats Monkeys Dogs Weight Each 22010 g g 400 g 241.60 g kg . . 3.0kg . 3.0 kg . . 14.0 kg Dogs are generally, the worst offenders as far as.odor generation is concerned. t Decontamination of exhaust air is recommended in populated areas. : For good air quality conditions the following space per animal and total air circulation (all outdoor or decontaminated in'recirculation) should be provided: nima.1 . .... cu ft . . . . cfm Mice 3 ... 0.5 Rats . 4 . 0.75 Guinea Pigs 6 1.0 Rabbits 10 1.9 Hamsters 8 1.5 Cats 35 10.0 Dogs 150 28.0 IndustrialAir Conditioning 941 , Table lv i. Temperatures'and Humidities Applicable to Industrial ' Air Conditioning--(Continued) Process - Temp. F ` R.H. % . PHOTO STUDIO 74 75-80 70 72 70-75 60 - ......... 50- - . 70 ` - *: 65 60 .- : 45 1 'V ' " ' Heat liberated during printing, enlarging and drying processes is removed through an independent ex haust system, which also serveathelamp houses and dryer hoods. -> . Dust control is essential, and absolute filtration is required in some areas. ,. Process '- ' .Temp. F PHOTO MATERIAL R.H. % ; 20-125 65-75 70-75 70-75 60-80 40-50 40-80 40-60 40-65 45-50 40-50 . 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 - . . . - PLASTICS Manufacturing areas: . - '` Cellophane wrapping.;li..________. ... .>y ............... i*.. Absolute filtration is required in some areas. Collection andremoval of dustand fumes is essential. Temp. F - R.H. % ; 801 1 - . 75 to 80 . . ' 25 to 30 : . 45 to 65 . * - -- . '; ' ' Process '' " ' PLYWOOD Temp. F " R.h. % 90 60 90 15 to 25 POULTRY RAISING Brooder: Battery room: ` 70-75 70-75 50-60 70 50-60 45-60 70-75 70-80 Maximum ventilation is required for laying quarters during the summer months, while an attempt is made to maintain a temperature 10 deg above or below outdoor temperature during the winter, to condensation on the exterior walls. This applies to houses not having forced ventilation systems. Process Temp. F PRECISION MACHINING Spectrographic analysis............................................................. Gear matching A special assembly room.............' Cement & due ntamip Precision part* mMhlnin^ . 75-80 75-80 65 75 R.H.% . 45-50 35-40 50 45-50 942 CHAPTER 44 .1952 Guide - Table 1. . Temperatures and Humidities Applicable to Industrial Air Conditioning--(Continued) . Process Temp. F R.H. % PRECISION. MACHINING (Continued) .- 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. _. . , Process PRINTING Temp. F R.H. % . Pressroom: Stockroom: ' " 5 to 8% above pressroom b 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 higher relative humidity at start. All printing requires conditioned paper otherwise it will not lie fiat, with 40 to 45 percent R.H. low limit to eliminate static electricity; and 60 percent R.H. high limit to prevent swelling of the rolls and slow ink drying. 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' forall exoept 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 heating 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 offioe areas. Process Temp. F REFRIGERATION EQUIPMENT Compressor Assembly....................................................................... Refrigerator Assembly....................................................................... 75 70 to 76 75 65 to 82 . R.H. % 40 30 to 45 30 to 50 47 Process . Temp. F RUBBER DIPPED GOODS R.H. % , 90 80 . 75-90 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 943 Table. 1. Temperatures and Humidities Applicable to. Industrial Air" Conditioning--(Continued) Process Temp. F TEXTILES Cotton: Opening........................................................................... Picking.......................................................................................... Carding, Winter...............;...................................................... Carding, Summer........... .............................................................. Carding, Summer...................................................................] -.or . Carding, Summer................................................ ......................or Drawing...................................................................................... Roving............................................ ..............................;............ Ring Spinning . Conventional.......................................... '............................. : long Draft....................................... :.................................... Frame Spinning................... .....................................;............ Spooling & Warping............................................................... Weaving..................................................... '............................... ; Cloth Room................................................................................ ' Combing..:................ .....................:.............................. ......... Linen: Carding............................................................................. Spinning.............................. ...................................................... Weaving........................................................................................ Woolens: Pickers................ Carding.............................. Spinning............................ Dressing............................. Weaving Light goods.................. Overcoating (32 os.). Drawing............ ................ Worsteds: Carding......... Combing....................... Gilling............................ Top Storage................. Drawing........................ . . Cap Spinning............... Spooling & Winding. Weaving.......................... Finishing..................... | Silk: Preparatory.. Weaving................ Dressing................ Spinning............... Throwing............ . Rayon: Spinning............................. Throwing......................................... Weaving Regenerated............................... Acetate......................................... . Spun rayon................................ - Carding, roving,' drawing......... ' Knitting ' ' Viscose or cupram monium. Acetate___ _ ..........:................ Laboratory (ASTM)................. Rayon synthetic fiber processing:. Viscose ' Preparatory................................... Weaving.......................................... . Celanese.............................1................ Preparatory................................... Weaving........................................... Nylon Preparatory................................... Weaving........................................... 70-75 75 75-80 83 85 87 so . 80 .-}* : -. * , 55-60 * ' 55-60 .55 ' . 90 , . 80 . . 70 . . - 60 60 . 80-85 80-85 80-85 78-80 78-80 ' 75 .75 70 . r .. 55 . 55-60 65 70-85. 65-70 - ; 50-65 75-80 75-80 80 .. x -. 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 ' 65 80-85 . 65-70 80-85 . . 65-70 70-85 .. 75-80 80-85 65 80-85 . 50-55 75 : 65-70 80 55-70 75 . . - 60 80 80 80 80 80 80-90 ' 80 . 60-65 60-70 60-65 65-70 60 50-60 55-60 80 80 .80 75-80 80-90 ' 50-65 55-60. 80 ' 50-60 . 50-60 80-85 80-85 70 65 60 . 65 80 . 80 80 80 80 80 . . . . 60 60 70 70-75 50-60 50-60 Cotton: Relative humidity maintained, in ring spinning depends on staple, twist and whether leather aprons are used for conveying long draft stock. Aprons readily absorb moisture wwalwg cotton to stick when relative humidity is above 55 percent. ", With conventional 3 or 4 roll spinning, relative humidity may be as high as 70 percent dependent upon draft, twist and staple.. -- , .. .- . Relative humidity carried in cotton weaving depends upon construction of the doth. When automatic machines are to be tended and the warps are heavily sized, it may be as high as 90'percent. Woden: In woolen spinning, the relative humidity maintained for mules is generally 55 percent with conditions over frame spinning at 55 to 60 percent. Both types of spinning depend on the of stock spun, also the regain in the roving. ' '. . ' ` 944 CHAPTER 44 1952 Guide Iv ' - Table 1. Temperatures and Humidities [Applicable to . Industrial Air Conditioning--^(Concluded) TEXTILES (Continued) 1 ' Worsteds: Top storage temperature depends on whether cellar long period conditioning at low temperature or quick conditioning at high temperature is used. Weavingrelativehumidifcydependsuponstaple, quality and construction. ... Filtration of air is essential. . . .. Rayon manufacture: The steeping room, where sheets of raw material are dipped in caustic soda then broken into a fine matted crumb, is held at 70 F and 55 percent relative humidity. Relative humidity is -held down to prevent condensation on cold pipes and jackets. . - ... In churn room, where sodium cellulose is converted into cellulose xanthate, temperatures of 75 to 80 F are while humidity control is not important. Room temperatures are held below 85F during the summer months. '' The crumb is dumped into aging tanka located in a room held at 73' F with no humidity control. . 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 Twntoriftl ia 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 80F. Relative humidity is held at 55 percent. - -: .. Process Temp. F R.H. % TOBACCO Cigar and cigarette making............................................................. Softening................................................................................................. Stemming and stripping................................................................... Packing and shipping........................................................................ Filler tobacco casing and conditioning...................................... Filler tobacco storage and preparation ....................................... Wrapper tobacco storage and conditioning.............................. 70 to 75 00 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 affect 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 945 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-diy 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 46). 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 946 CHAPTER 44 1952 Guide ' . Table 2. Regain op Hygroscopic Materials Moisture Content Expressed in Percent of Dry Weight of the Substance at Various . Relative Humidities--Temperature, 75 F Class]- Description Relative Hojudot--Pee Cent Authobitt 10 20 30 40 50 60 70 80 90 - --" ' Cotton ' . Sea island--roving . 2.5 3.7 4.6 53 6.6. 7.9 93 11.5 143 HufhiKftpift Cotton American--cloth ' 2.6 3.7 4.4 5.2 33 63: 83 too 143 Schloesing Cotton Absorbent ' ' 4.8 9.0 12.5 15.7 183 203 223 243 25.8 Fuwa Natural Textile Wool Silk ' ' ' Australian merino--skein 4.7 7.0 8.9 103 123 14.9, 173 19.9 23.4 Hartahorne Raw chevennes--skein 3.2 '5.5 6.9 8.0 8.9 103 11.9 143 183 Schloesing linen Table cloth 1.9 2.9 3.6 43 5.1 6.1 7.0 8.4 103 Atkinson linen '' Dry spun--yarn 3.6 5.4 6.5 73 83 8.9 93 11.2 133 Sommer Jute Hemp Average of several grades 3.1 5.2 6.9 83 10.2 123 14.4 173 203 Storch Manila and sisal--rope 2.7 4.7 6.0 7.2 83. 9.9 ii-6 13.6 15.7 Fuwa Rayons Viscose Nitrocellu lose Cupramonium Average skein Cellulose Acetate Fiber 4.0 5.7 6.8 7.9 9.2 103 12.4 143 16.0 Robertson 0-8 1.1 1.4 1.9 2.4 3.0 3.6 43 53 Robertson M. F. Newsprint Wood pulp--24% ash H. M. F. Writing Wood pulp--3% ash 2.1 3.2 4.0 4.7 S3 63 73 8.7 10.6 U. St B. of S. 3.0 4.2 5.2 6.2 7.2 83 9.9 119 143 U. S. B. of S. Piper White Bond Rag--1% ash 2.4 3.7 4.7 53 63 73 83 10.8 133 U.S.B.of& Com. Ledger 75% rag--1% ash 3.2 4.2 5.0 5.6 63 6.9 83 103 13.9 U.S.B. ofS. Kraft Wrapping Coniferous 3a 4.6 5.7 6.6 7.6 8.9 10.5 12.6 14.9 U. S. B. of S. Leather Sole oak--tanned 5.0 83 11.2 13.6 16.0 183 20.6 24.0 293 Phelps Catgut Racquet strings 4.6 7 2 8.6 102 123 143 173 193 21.7 Fuwa Clue Hide 3.4 4.8 5.8 6.6 73 9.0 10.7 113 123 Fawn . Organic Rubber - . Sofid tires . an a2i 032 044 034 066 076 0.88 099 Fuwa Wood Timber (average) 3.0 4.4 5.9 7.6 93 113 (4 0 173 22.0 Forest P. Lab. Soap White 1.9 3.8 5.7 7.6 10.0 12.9 163 193 233 Fuwa Tobacco . Cigarette 5.4 8.6 11.0 133 16.0 193 25.0 33.5 50 0 Ford White Bread 03 1.7 3.1 43 63 83 113 143 19.0 Atkinson Crackers 2.1 2.8 33 3.9 5.0 63 83 10.9 14.9 Atkinson Food-' . Macaroni stuffs Flour ' 5.1 7.4 83 10.2 117 13.7 163 19.0 223 Atkinson. 2.6 4.1 53 6.5 8.0 9.9 12.4 15.4 193 Bailey Starch 2.2 33 5.2 6.4 7.4 83 93 10.6 12.7 Atkinson Gelatin . . 0.7 1.6 23 33 4.9 63 7.6 93 11.4 Atkinson Asbestos fiber Finely divided. 0.16 0.24 0.26 032 041 031 062 073 0.84 Fuwa Shea Gel' -; 5.7 9.8 12.7 153 173 183 203 213 22.6 Fuwa Inorganic Domestic Coke 0.20 0.40 0.61 0.81 1.03 134 1.46 1.67 139 Selvig Activated Charcoal Steam activated 7.1 14.3 223 26.2 283 293 30.0 313 32.7 Fuwa Sulfuric Acid HtSO* . 33.0 41.0 47.5 523 S7.0 613 67.0 733 823 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 IndustrialjAir Conditioning 947 allow the internal gases to escape freely-as the chemical oxidizers cure the varnish from -within. This produces a surface free from bubbles and a homogeneous film throughout. . Desirable temperatures for drying varnish vary with the type. A relative humidity of 65 percent is beneficial 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 carbon 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 tobacco, 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, as the one controls the rate of cooling, while the other, through evapora tion, changes the density of the solution. In the coating pans for pills, gum, and nuts, a heavy sugar solution is added to the tumbling mass. As the water evaporates, each separate piece is covered with crystals of sugar. A smooth, opaque coating is only accom plished by blowing into the kettle the proper amount of air at the right dry- and wet-bulb temperatures. If the cooling and drying are too slow, the coating will be rough and 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. 948 CHAPTER 44 1952 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. 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. 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-thanaverage 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, 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 a relative humidity of 55 percent or more. As some machines consume 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, 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 949 CALCULATIONS . The methods for determining the heating and cooling loads for the various industrial processes are similar to those outlined in Chapters 11 and 12. 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 10 gives information on natural ventilation. If mechanical ventilation is to be used, Chapter 32, Fans; Chapter 30, Air Distribution; Chapter 31, Air Duct Design; Chapter 33, Air Cleaning; and Chapter 34, 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 45, and will not be further treated in this chapter. 2. A system employing the dilution method will usually be indicated where the contamination originates at scattered points dispersed generally throughout the area. .. 3. Combination of local exhaust and dilution methods is often economical, since well designed exhaust hoods or openings, 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.: 950 CHAPTER 44 1952 Guide Design of Dilution Systems . The first step in the design of a system employing the dilution method is to determine as exactly as possible the nature and extent of the 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 system. 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 , and un 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 data are tabulated m 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: . . . V X 10` (MAC) - (SAC) (1) 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 weight 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, . .. . . - `W ' t -f- 460 ` - - -' cfm (vapor) ="-- X 359 X------ 492 . (2) - where ' W = rate of generation of contaminant, pounds of liquid solvent per minute. Jf, = molecular weight. t -- air temperature, Fahrenheit. . - A special case occurs where local concentrations of solvent vapors of the breathing zone, 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 45) will generally be the recommended treatment for these particulate contaminants.. . Industrial Air Conditioning 951 3. Sensible Heat. 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 (ti- t0) XdXc where Q = quantity of air circulated, cubic feet per minute. -. H = rate of generation of heat, Btu per minute. ti = allowable temperature in the space, Fahrenheit. . . ", Jo = 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 U approaches too closely the temperature to 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. Control of Radiant Heat . One of the most difficult problems of ventilation engineers is found in the so-called hot industries (steel mills, paper mills-, foundries, etc.) where radiant heat from high temperature surfaces is a most important factor, the magnitude of which is not always appreciated. Since ventilation can not remove radiant heat, it is worthwhile to consider using low emissivity materials and shielding to minimize conversion to sensible heat due to interaction with surfaces within sight of the radiant source. Odors . There is little information available either on 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 contaminant, 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. '' : 952 CHAPTER 44 1952 Guide . _ BIBLIOGRAPHY Processing Air Conditioning Design Conditions for Various Industries, by N..N. Wolpert (.Beating and Ventilating, May 1949, p. 70; June 1949, p. 73; July 1949, p. 79; Aug. 1949, p. 102). .. \ Air Conditioning Design Data for Commercial Applications, by N. N. Wolpert (Heating and Ventilating, Feb. 1950, p. 68). _ _ ASRJE Data Book 1950 (American Society of Refrigerating Engineers). Refrigeration of Oranges in California, by H. M. Hendrikson and J. R. MacRill, 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. MacRill, Refrigerating Engineering Application Data No. 18-R (American Society of Re frigerating Engineers). ,,_ Air Conditioning in the Bakery, by W. L. Fleisher (A.S.H.V.E. Transactions, Vol.37,1931,p. 141). ,,. ,. 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, Renting, Piping and Air Conditioning, October 1947, p. 107). Air Conditioning in Candy Manufacture, by H. C- 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 (Healing 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 (Heating and Ventilating, October, 1935, ^ 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 (Heating 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). . Close Machine 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). Industrial Air Conditioning 953- BIBLIOGRAPHY . (Continued) /. . Processing (Continued) 1 , .' 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 (Transactions Society of Motion Picture Engineers, April, 1927, Vol. XI,: No.'30 pi 335-365). - " - - -, ' " 1 ' Industrial Air Conditioning, by F. F. Stevenson (Healing, 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). . -' Reducing Heat Loads in Industrial Air Conditioning, by L. R. St. Onge (Refrigeiat- ingEngineering, January 1946, p. 35). ' .... Air, Light, and Sound Controlled in Western Electric's New Plant (Heating, Piping and Air Conditioning, Nov. 1948, p. 79). , New IBM Plant Addition, Poughkeepsie, N. Y., by J. T. Browne (Healing, Piping and Air Conditioning, Jan. 1949, p. 111). 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, Healing 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, 1949, p. 440). Air-Conditioned Crane Cabs, by B. R. Small (Industrial Hygiene Foundation, Precentive 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 Veniilationl 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. Wells and E. C. Riley (The Journal of Industrial Hygiene and Toxicology, Vol. 19, No. 10. De cember, 1937). Industrial Cooling as a Production Aid, by J. Partington, Jr. (Healing 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). Ventilation Requirements for Industrial Solvents, by W. C. L. Hemeon (Heating 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 Dust Explosions, by Hylton R. Brown (Healing 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 (Heating, Piping, and Air Conditioning, April, 1946, p. 106). 954 CHAi P' TER 44 1952 Guide -Air Conditioning Requirements for Workers in Factories, by H. A. Mosher (Heat ing, Piping and Air Conditioning, August, 1946, p. 82). ... , . Hot Weather Limits Hard Work: (Brief summary of investigation done for Army Quartermaster Corps, by Department of Physiology, Medical School, University of Indiana. Heatingand Fenfifatfng,,.August,. 1947, p. 11(IU ; Methods Used in Determining the Health Hazards Arising from the Inhalation of Various Chemicals, by Francis F. Heyroth (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, January, 1947, p. 109, and discussions, Heating, Piping and Air Conditioning, April, 1947, p. 113). . .' Air Recirculation from Exhaust Systems, by John M. Kane (Heating and Ventilat- tnffShouM'li^iBePReMrculated from Industrial Exhaust Systems? by Allen D. Brandt (Healing, Piping and Air Conditioning, August, 1947, p. 69). ` Dehumidification Methods and, Applications; by John Everetts, Jr.^(A,S.ll.V .Ji. Journal Section, Heating, Piping and Air Conditioning, December, .1946,, p. 12HRating Dynamic Dehumidification .Equipment,; by -E. .R. Queer and E. K. McLaughlin (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, January, 1947, p. 103). '' CHAPTER .45 INDUSTRIAL EXHAUST SYSTEMS i Classification of Systems, Hood Design Principles, Capture'. Velocity and Hbiid Suction, Duct System Design, Resistance of System, Efficiency of System, Air Flow Producing Equipment, Protection Against Corrosion and Abrasion ' IN many industrial plants some type of exhaust system designed ..to collect and remove dusts, fumes, mists, vapors, and gases is essential in order to promote efficiency, economy, and safety of operation. Defini tions of these various contaminants are included in Chapter 8, Air Con taminants. ' The theory of air flow in an exhaust system in the following, paragraphs A to D will be found in a publication1 of the American Foundrymen's Association. . A. When the air flow producing equipment of an exhaust system is properly oper ated, it will produce a negative pressure (below atmospheric) in the exhaust side of the system sufficient to overcome all resistance, and to sustain the desired air ve locity; and, further, will overcome all resistances on the discharge or positive pressure side of the system so that the air drawn through exhaust inlets will be discharged against atmospheric pressure. .` . B. An exhaust system is entirely dependent on a sufficient volume of air flowing into the exhaust inlets to catch the matter to be exhausted before such matter has ah op portunity to diffuse into the general atmosphere of the work place or room. ` . C. The velocity of the air flowing into an exhaust inlet is usually of secondary importance, and becomes an essential factor only when a certain velocity is required to overcome some force action on the matter to be caught. . The velocity within an exhaust system is only important to the extent that it shall be sufficient to convey the entrained matter and prevent it from settling or dropping out in the piping sys tem. Velocity in terms of velocity pressure is most essential in designing a system; because it is the basis upon which all calculations are made. In testing and checking a system the velocity, as determined from the velocity pressure reading obtained by means of a Pitot tube, is the only true indication of the exact air flow in a pipe or system. ;' D. The total pressure within an exhaust system is only of importance in deter mining the power required to operate the system. Total pressure tests do not in dicate the proper functioning of an exhaust system as related .to the volume And velocity of the air flowing into an exhaust inlet. :' General design information is included in this chapter which is intended to relate primarily to industrial exhaust systems. ' . CLASSIFICATION OF SYSTEMS In general, there are two basic layouts of exhaust systems, the central and the multiple unit system. In the central system a fan is located near the center of operations with a. piping system radiating to the various machines to be served. In the multiple unit system, which is sometimes employed where the machines to be served are widely scattered, or where the operations are apt to be independent or intermittent, small individual exhaust fans are located at the center of the machine groups or at each machine. The unit arrangement has the advantage of flexibility. Exhaust systems may be classified with respect to the nature of the material to be handled by them as (a) those handling dusts and certain fumes and mists of large particle size; and (b) those handling vapors,.gases and certain fumes and mists of small particle size. Design details differ in systems serving dust producing operations and those exhausting the 955 956 CHAPTER 45 1952 Guide more vapor-like matter, even though the same basic theories govern both classes. Dust or gas may be captured by enclosure or by open hoods with posi tive inward air movement. With some classes of machinery it is not feasible to hood the machines closely, and in. these cases open hoods over or adjacent to the machines are provided to collect as much as possible of the dust and fumes. Examples of these classes include such machines or operations as pickling tanks, melting furnaces, arc welding, and monu ment finishing operations. .. Open hoods should be placed as close to the source of dust or fumes as possible, with due regard to the movements of the operator. In no in stance should the operator be located between the source of dispersion and the exhaust hood or enclosure. When the hood must be placed at some distance above the machine, it should be large enough to cover a large area, as dispersion (considering dust) is usually quite rapid. .Some consideration should be given to the natural movement of the contaminant. In many cases there are convection currents and other atmospheric disturbances in the work room. These disturbances diminish the tendency of dust and fumes to settle from the room air. . In some classes of operation, the main objective is to prevent the escape of dust into the surrounding atmosphere, and the removal of some dust from the machine of enclosure may be merely incidental. The dustcreating apparatus is enclosed within a housing which is made as tight as ' practicable, and sufficient suction is applied to the enclosure to maintain an inward air flow through all cracks and openings, thus preventing escape of the dust. While the exhaust system is required to handle only the air which enters through the crevices and openings in the enclosure, in many installations leakages are very high, and great care is required to reduce such leakages to a minimum. . Certain dust and fume producing operations are best carried on by iso lating the process in a separate compartment or room, and then applying general ventilation to this space. HOOD DESIGN PRINCIPLES2-6-6-7 The first and most important steps in the design of a local exhaust sys tem are to determine the number and shape of hoods or enclosures, and the size of the branch connections. No general rules, however, can be given since hood and duct designs are determined by the characteristics of the operations to which they are applied. When a tentative decision regard ing the set-up has been made, it is next necessary to obtain the suction and air velocities required to effect control. At this point, the designer must rely upon the prevailing practice, and on such physical data relating to hoods, duct systems, and collectors as are available. In general, the most important requirements8 of an efficient local exhaust system are:- . 1. Hoods, ducts, fans, motors and collectors should be of adequate size and type. 2.. The air velocities should be sufficient to control and convey the materials col lected. 3. The hoods and ducts should be placed so as not to interfere with the operation of a machine or any working part. . 4. The system should do the required work with a minimum power consumption. '5.. When flammable contaminants are conveyed, the piping Bhould be provided with an automatic damper in passing through a fire-wall (Refer to Pamphlet No. 91, National Board of Fire Underwriters).? Industrial Exhaust Systems 957 6. Ducts and all metal parts should be grounded to reduce the danger of dust ex plosions by static electricity: Motor and starting equipment should conform to Article 500--Hazardous Locations--of the National Electrical Code.10 ' 7. The exhaust system should be readily accessible for inspection and main tenance; CAPTURE VELOCITY AND HOOD SUCTION The removal of dust or contaminant by means of an exhaust hood re quires a movement of air, at the point of origin, sufficient to carry it into the exhaust system. The air velocity necessary to accomplish this depends upon the physical properties of the material to be controlled and the direc tion and speed with which it is dispersed. If the dust to be removed is already in motion, as is the case with high-speed grinding wheels, the hood must be installed in the path of the particles so that a minimum ajr vol ume may be used effectively. It is always desirable to design and locate Table 1. Minimum Aib Velocities Required at Point op Origin to Capture Contaminant Effectively Condition op Generation op Contaminant Released without noticeable movement Released with low veloc ity . Minimum Capture Velocity, FPM 50-100 100-200 Active generation 200-500 Released with great force 500-2000 Process Evaporation of vapors; exhaust from pick ling, washing, degreasing, plating, weld ing, etc. Paint spraying in booth; inspection, sort ing, weighing, packaging, low speed con veyor transfer points; rotating mixtures, barrel filling. .. Foundry shakeout, high speed conveyor transfer points, crushers, screens. Grinding, tumbling mills, abrasive cleaning. a hood so that the volume of air necessary to produce results is as small as possible. This will reduce the size of equipment, the power'required - by the system, and also the heating load, requirements in winter. Capture Velocities Data for the selection of capture velocities of many operations are not available, but it is safe to assume that for most dusty operations velocities should not be less than 200 fpm at the point of origin. Recommended minimum capture velocities for various processes are given in Table 1. The method for determining, approximately, the quantity of air that must be exhausted to produce these capture velocities at the point of ori gin, is given in Equation 1: . ,. Q = V(10X + A) (l) where 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 hood to the point where the air velocity is V feet per minute. A = area in square feet of the hood opening. . 958 CH.A/ P^ TER 45 " . ' 1952 Guide ' ' Table 2. Bbanch Pipe Size fob Woodworkino Machine Hoops Based on a Pipe Velocity of 4000 fpm. ; Type of Machine Self feed table saw ' Other single saws . Saws with Dado Head' Band saws . Disc sanders Triple drum sanders Min. * In. Branches, '' Max. ` \ Minimum Diameter, - In. Bottom Branch i Top Branch Others ' 2 5 4. 18 1 .18 1 4; . .5; ; '1 ' 15 2 2 .4 4 2 3. 2 5 4 3 62 5 5 18 ' 1 - 4 18 28 1 5 26 . 32 2 4 4 32 38 2 5 4 38 48 3 5 4 4 30 1 " 7 30 36 1 8 36 42 1 9 42 48 1 10 Single drum sanders: (area in sq in.) Horizontal belt sanders Vertical belt sanders : Jointers Single planers Tenoner . 350. 700 1400 9 6 9 8 20 . , 26 350 700 1400 2800 9 14 6 9 14 8 20 20 26 36 1 2 2 1 1 1 1 1 :1 . ,1 1. 2 4 5 6 7 5 6 4 5 6 4 5 5 6 '7 1'5 - 4 4 5 - aNot over.10 in. diameter. ' No set rule can be given regarding the shape of a hood for a particular operation, but it is well to remember that its essential function is to create an adequate velocity distribution. The fact that the zone of greatest effectiveness does not extend laterally from the edges of the opening, may frequently be utilized in estimating the size of hood required. Where complete enclosure of a dusty operation is contemplated, it is desirable to leave enough free space to equal the area of the connecting duct. Hoods for grinding, polishing, and buffing should fit closely, but, at the same time should provide an easy means for changing the wheels. It is advisable to design these hoods with a removable'hopper at the base to capture the . heavy dust and articles dropped by the operator. Such provisions are of Industrial Exhaust Systems 959 assistance in keeping the ducts clear. The-air quantity required to cap ture dust which is_.thrown or projected in a direction, away from the hood ' at considerable velocity, may often be reduced by effective baffling or par tial enclosure of an operation. This procedure is strongly urged where dusts are directed beyond the zone of influence of the hood. ... .. . Air Flow from Static Readings . State codes for local exhaust systems at certain operations list minimum static suction requirements which may range from 1 in: to 5 in: water column. Frequently, in grinding, buffing, and polishing operations, a large part of the wheel must be exposed, and the dust-laden,air-within the hood is thrown outward by the centrifugal action of the wheel, thus counter acting useful inward draft. - The static suction at the throat of a hood is frequently used in practice, as a measure of the effectiveness of control. Where the hood coefficient is known, the volume of air flow through any hood may be determined from the equation: Q = 4005 fAy/h, (2) where . Q = quantity of air exhausted, cubic feet per minute. A = area of connecting duct, square feet, . ft, = static suction measured at approximately 3 diameters from throat of hood, inches of water. . / = orifice or restriction coefficient which varies from 0.6 to 0.95, depending on ' the shape of the hood.s An average value of / is 0.8, although for a well-shaped opening a value of 0.85 to 0.9 may be used. The factor/is determined from the equation: ft. ./ = ft. (3) where ft. is the velocity head in the connecting duct. The static suction is not a good measure of the effectiveness of-a hood, unless the area of the opening and the location of the operation, with re spect to the hood, are known. This is clearly indicate! by Equation 4 which shows that the velocity at any point along the axis varies approxi mately inversely as the square of the distance. This fonnula, coupled with Equation 2, should serve to indicate the velocity ` conditions to be expected when operations are conducted externally to the hood opening. Axial Velocity Formula for Hoods ., When the normal, flow of air into a hood is unobstructed,' Equation 4 may be used to determine the air velocity at any point along the axis:11 0.1 Q V= x* + 0.1 A (4) where ' V = velocity at point, feet per minute. Q = quantity of air exhausted, cubic feet per minute, x = distance along axis, feet. A = area of opening,.square feet. 960 CHI A^PTER 45 1952 Guide Design Based on Total. Air Flow '' Where the foregoing factors Ire not known, the usual method of de signing an exhaust system is to base the air flow through the system on rates of flow (through each hood) which have been found by expeiehce to provide adequate control. For woodworking systems the sizes of branch connections in common use are given in Table 2. ., Similar data for grinding and buffing wheels are given in Table 3. Velocity Contours , - It is possible, by use of a specially constructed Pitot tube,12 to map con tours of equal velocity in any axial plane located in the field of influence. It has been found that the positions of these contours for any hood can be Table 3.- Branch Pipe Sizes fob Gkinding and Buffing Hoods Based on a Pipe Velocity of 4500 fpm: Type of Wheel Wheel Size Diameter, In. Min. Max. Maximum Width In. Area Sq In. Branch Pipe Minimum Diameter, In. Grinding 9 9 18 18 24 24 30 30 36 Disc Grinding 20 20 30 8 Buffing, Polishing and Scratch 8 16 Brushing 16 24 24 30 i 30 3 175 4 300 5 500 6 700 .300 2. 3 4 6 50 150 300 600 3 .4 5 6 7. 4 5 ' 3^ 4 5 6 expressed as percentages of the velocity at the hood opening, and are purely functions of the shape of the hood.1* , Further, the velocity contours are identical for similar hood shapes when the hoods are reduced to the same basis of comparison. These facte are. applicable to all hood problems so that, when the velocity contour distribution is known, the air flow required can be determined. Fig. 1 shows the contour distribution in two axial planes perpendicular to the sides of a rectangular hood having a side ratio of one-half. The distribu tion shown is idential for all openings with a similar, side ratio, provided the mapping is as shown in the figure. The contours are expressed as per centages of the velocity at the opening. .. Low Velocity Systems On multiple installations of the same operation, it is often possible to institute a great saving in power cost by designing an exhaust system using low velocities in the main ducts. Such a system, for use in grinding and shaping porcelain, has been described.14 In these operations, the separate machines are grouped around a central plenum chamber, and exhausted by means of a low pressure fan connected to the plenum. In Industrial Exhaust Systems 961 one such case, a power saving of over 90 percent was obtained.. A similar design technique15 has been described for use in ventilating plating tanks. Canopy Hoods 1: Canopy hoods are being replaced by other types of hoods, such as siotted hoods at tank operations. : Where canopy hoods are used, they should ex tend 6 in. laterally from the tank for every 12 in. elevation and, wherever possible, they should'have side and rear, aprons so as to prevent short- Fig. 1. Velocity Contours fob Rectangular Opening with a Side Ratio of . One-Half. Contours are Expressed as Percentages of the . . Velocity at the Opening ' circuiting of air from spaces not directly over the vats or tanks. In most cases, hoods of this type take advantage of the natural tendency of the vapors to rise, and air velocities may be kept low. Gross drafts'from open doors or windows disturb the rise of the vapors, and therefore 'considera tion must be given them. The air velocities required also depend upon the character of the vapors given off. The recommended minimum- cap ture velocity is 100 fpm. ' : . The quantity of air which must be exhausted to obtain any given cap ture velocity is expressed by the following equation: Q = 1.4 PDV where .. , Q = quantity of air exhausted by hood, cubic feet per minute. P = perimeter of the tank, feet. D = distance between tank and hood opening, feet,V =' capture velocity, feet per minute. ' (5) . . ' 962 CHAPTER 45 ' 1952 Guide Lateral Exhaust Systems ' : Lateral exhaust, as developed for chromium plating,16 is preferred to canopy type hoods. The method operates by drawing air and fumes laterally across the top of vats or tanks into slotted ducts located at the top and extending fully along one or more sides of the tanks. The slot width is usually based on a slot velocity of 2000 fpm, but'should not be less-than 1 in. wide. The hood should not be required to draw the air laterally for a distance of more than 24 in., and the level of the solution should be kept 6 to 8 in. below the top of the tank. If width of tank is. over 24 in., a double lateral exhaust should be used with slots on both sides. It has also been determined that a similar control may be used for tanks wider than 3 ft when the same velocity (2000 fpm) is maintained through a slot which is increased \ in. for every foot of width greater than 3 ft. When these slots must be extended more than 6 ft in length, some method of spreading the flow is necessary to provide even air flow distribution through the entire slot length. This can be accomplished by tapering the slot, which incidentally will add to the resistance of the system. A more economical approach is to place properly spaced vanes in the side ducts, or to branch the side ducts.11 Spray Booths In the design of an efficient spray booth, it is essential to maintain an even distribution of air flow through the opening and about the object being sprayed. While in many instances spraying operations can be per formed mechanically in wholly enclosed booths, the volatile solvent vapors produced by spraying operations may reach injurious or explosive concen trations. At all times, the concentrations of these vapors, and particu larly those containing benzol, should be kept well below 100 parts per million in the breathing zone of the worker. Vapors from many spraying operations are dangerous to the health of the worker, and care should be taken to minimize exposure to them. It is recommended in the design of spray booths that the exhaust duct be located at the end of the booth opposite the opening. In front of this duct should be placed baffle plates which will cause a uniform air velocity distribution across the frontal area. The air volume should be sufficient to maintain a velocity of not less than 150 fpm over the open area of the booth. . Spray booths may be of either the dry or wet type. The latter is the more modem design, provided with a water-wash section for the removal of the solid over-spray contaminants, and for the absorption of water- soluble thinners or solvents. . . . . The most modem innovation is the electrostatic spraying and detearing unit. Objects to be sprayed are passed through a high tension electro static field, which not only produces a more evenly sprayed surface, but materially reduces excessive over-spray. The detearing unit removes tear drops of sprayed material from the edges or ends of air-drying sprayed ob jects as these objects pass through a high tension electrostatic field. Hoods for Chemical Laboratories Hoods used in chemical laboratories are generally provided with sliding windows which permit positive control of the fumes and vapors evolved by the apparatus. Their design'should offer easy access for the installa tion of chemical equipment, and should be well lighted. Air velocities should not exceed 100 fpm when the window is fully open. Industrial Exhaust Systems 963 Kitchen Hoods The length and width of kitchen hoods should be such as to extend be yond the extreme projection of the ranges, broilers, etc., over which they are installed. The minimum projection or overlap should be 12 in. Where space conditions permit, range hoods should be about 2 ft high in order to provide a reservoir to confine momentary bursts of smoke and. steam until the exhaust system can evacuate the hood. Range hoods should be located as low as possible to increase their effectiveness.; In general, the amount of air to be exhausted from restaurant range hoods is at the rate of 100 cfm per square foot of face area. In some cases, where the application is principally frying, and where it is not practicable to install a hood 2 ft high, it is recommended that the face velocity be increased from 100 to 150 fpm, depending on peak load conditions in the kitchen. Exhaust connections to range hoods should always be made at the top and back of hoods, and should be spaced preferably not more than 6 ft apart, and be rectangular in shape with the long side parallel to the back of the hood. Exhaust openings into range hoods should be designed to maintain a velocity of 1500 to 1800 fpm. . An approved fire damper with fusible link should be (and is required by code in many states) installed in the main exhaust duct or branch ad jacent to the range hood. Should there be more than one hood connected to a common duct, then the branch duct to each hood should be provided with a fire damper. Access doors should be provided, at the fire damper for purpose of inspection, cleaning, or for renewal of fusible link. All exhaust piping to range hoods, commonly called grease ducts, should be provided with tight fitting cleanout doors of adequate size to permit easy removal of grease. Some engineers use filters to advantage in hoods which are subject to grease conditions. , Hoods over steam tables should be of construction similar to range hoods. It is good practice to design such hoods with a face velocity of 60 to 70 fpm. Hoods over dishwashing machines are usually relatively small, and generally 1500 to 2000 cfm per hood are allowed, which is equivalent to a velocity of approximately 100 fpm per square foot of face area. Range hoods in diet kitchens are constructed the same as restaurant range hoods, but with less exhaust air per square foot of face area, depending upon the nature of the food cooked. Hoods are not often used in private residences, unless they are quite large and the consideration of expense is not important. For such residences the hoods should be designed on the same basis as diet kitchens. Most all residence kitchens can be effectively and economically ventilated by the installation of a built-in kitchen ventilator, which should be located in . an outside wall and in close proximity to the kitchen range. It has been found that the capacity of the built-in kitchen ventilator should be at least 350 cfm regardless of the size of kitchen! This can be justified on the Table 4. Approximate Conveying Velocities Material Conveyed Design Velocity FPM Vapors, gases, fumes, very fine dust................ Fine dry dusts........................................................ Average industrial dusts..................................... Coarse particles..................................................... Large particles, heavy loads, moist materials 2,000 3,000 3.500 3,500-4,500 4.500 and over 964 CHAPTER 45 1952 Guide basis that the smaller the kitchen the more concentrated the heat will be, thus requiring a more rapid rate of air change. Standard size, built-in kitchen ventilators are generally available in three sizes, namely,-350, 500 and j800 cfm. ..The proper size to use will depend on design conditions and available wall space. - . . DUCT SYSTEM DESIGN In designing a duct system, it is necessary to recognize a few funda mental principles, (see also Chapter 31). Knowing the quantity of air required, the size of the duct may be computed from Equation 6: A Q V where ` , A = cross-section area of duct, square feet. . Q = air quantity to be exhausted by. the duct, cubic feet per minute. V = velocity of air, feet per minute. (6) ' Air Velocities in Ducts ;; Where it is necessary to transport the particulate material collected in an exhaust system, minimum carrying velocities must be . maintained in the ducts preceding the collector. It has been found that good results are obtained when design air velocities in horizontal runs are not less than 2000 fpm, or not greater than 5000 fprn. When the dust being carried is organic and other than wood flour, or similar material, a velocity of 2500 fpm is adequate. Approximate required conveying velocities are given in Table 4. ' For duct systems wherein the air has no dust or solid load, a lower velocity is desirable, which may range from 1500 to 2500 fpm. . In view bf the fact that the horsepower required by a system depends directly On the resistance,, and the resistance is a function of the velocity, economical design requires velocities of this magnitude. . The equal friction method-is generally used for designing a duct sys tem, as. this insures equal resistance to air flow in all branches throughout the system (see Chapter 31). Long main ducts do not generally provide the most economical layout. Where it is necessary to ventilate a large number of machines, or'machines which are widely separated, it is desir able to locate the fan at approximately the. center bf the system. With this arrangement it is possible to choose a fan which will deliver the re quired air quantity against a lower resistance pressure, and this will gen erally result in a horsepower saving. ' . ' When a system carrying dust is designed with an oversize main duct to allow for future extension, the air velocity may be found to be too low to carry the dust, and serious plugging may occur. In this case it is desir able to install an orifice in the end of the pipe to allow for the lower air . quantity. Construction The interior of all ducts should be smooth and free from obstructions at joints, and soldered air-tight. Other sealing mediums are permissible where soldering is impracticable. Ducts should be constructed of galvanized, sheet metal, except when the presence of corrosive fumes or gases, temperatures above 400 F, or other factors would make galvanized material impracticable. For the usual ex- Industrial Exhaust Systems 965 Table 5. Gages op Metals fob' Exhaust Systems* Diameter op Round Pips or Greatest Dimension op Rectangular Pipe, '. Inches Thickness of Duct Material U. S. Gags Number For Highly Abrasive Matter. . For Other Matter . Up to 8 inclusive________________ Over 8 to 18 inclusive.- ... . Over 18 to 30 inclusive.__________ Over 30_________________________ 20 18 16 14 22 20 18 16 Fundamentals of Design, Construction, Operation and Maintenance of Exhaust Systems {American Foundrymen's Association, p. 53). . '' haust systems, the metal thicknesses shown in Table 5 are recommended. Elbows and angles should be a minimum of two gages heavier than straight lengths of equal diameter. Hoods should be a minimum of two gages heavier than straight sections of a connecting branch. Longitudinal joints of ducts should be . lapped and riveted or spotwelded on 3-in. centers maximum. Girth joints or ducts should be made with lap in direction of air flow, with 1 in. lap for duct diameters through 19 in., and 1J in. lap for diameters over 19 in. Elbows and angles should have an inside or throat radius of two pipe diameters whenever possible. Large radii are recommended for heavy concentrations of highly abrasive dusts. Elbows 6 in. or less in diameter should be constructed of at least 5 sections and, if over 6 in. in diameter, of 7 sections, with angles pieced proportionally. Hoods should be free of sharp edges or burrs, and re inforced to provide necessary stiffness. Transitions in mains and submains should be tapered with a taper 5 in. long for each 1 in. change in diameter whenever possible. All branches should enter the main at the large end of the transition at an angle not to exceed 45 deg, or preferably 30 deg. Branches should be connected only to the top or sides of mains, with no two branches entering diametrically opposite to each' other. Dead end caps should be provided within 6 in. from last branch of all mains and sub-mains. ' Cleanouts should be provided every 10 ft and near each elbow, angle, or duct junction in horizontal sections. Ducts should be supported sufficiently to place no loads on 'connected equipment, and to carry weight of a system plugged with material. The maximum distance between supports should be 12 ft for. 8 in. or smaller ducts, and 20 ft for larger ducts. Six inches minimum clearance should be provided between ducts and the ceiling, wall or floor. Blast gates for adjustment of the system should be placed near the connection of a branch to the main, ;and means of locking gates after the adjustments have been made should be included. Rectangular ducts should be used only when clearances prevent the use of round construction. Rectangular ducts should be as nearly square as possible. The weight of metal and the lap, and other ' construction details, should be the equal of round duct construction having a diameter equal to the longest side. All pipes passing through roofs should be equipped with collars so arranged as to prevent water from leak ing into the building. The main trunks and branch pipes should be as short and straight as possible.- , . Cleanout openings having suitable covers should be placed in the main and branch pipes so that every part of the system can be easily reached in case the system clogs. Either a large cleanout door should be placed in the main suction pipe near the fan inlet, or a detachable section of pipe, held in place by lug bands, may be provided. . 966 CHAPTER 45 1952 Guide - Every pipe should be kept open and unobstructed throughout its entire length, and no fixed screen should be placed in it, although the use of a trap at the junction of the hood and branch pipe is permissible, provided it is not allowed to fill up completely. The passing-of. pipes.through fire walls should be avoided, wherever possible, and floor sweep connections should be so arranged that foreign material cannot be easily introduced into them. . At the point of entrance of a branch pipe into the main duct, there should be an increase in the latter equal to their sum; Some state codes specify that the combined area be increased by 25 percent. While this is not always good practice, and is frequently done at the expense of a reduced air velocity, it is often done where future expansion of the exhaust system is contemplated. '' Duct Resistance ' - The resistance to flow in round galvanized duct, riveted and soldered at the joints, may be obtained from Figs. 1 or2, Chapter 31. The pressure drop through elbows depends upon the radius of the bend. For elbows Table 6. Loss Through 90-Deg Elbows Ratio of Elbow Center Line Radius to Pips Diameter or Depth ~ ' . J 'H : 2- . 21 . Approximate Loss in Percent . ox .Velocity Head ; - 80 31 22 19 whose centerline radii vary from lOO to 250 percent of pipe, diameter, the loss may be estimated from Table 6. .. , . . RESISTANCE OF SYSTEM . . The resistance of the exhaust system is composed of three factors: (1) loss through the hoods, (2) collector drop, and (3) friction drop in the duct system. .'. The loss through the hoods is usually assumed to be equal to one-half the suction at the hoods. Where possible the resistance of the particular collector to be used should be obtained from the manufacturer. . Friction drop in the pipes must be computed for each section where there is a change in area or in velocity. ' The velocities should be-found in each section of pipe, starting with the branch most remote from the fan. The friction drop for these sections can be determined by reference to Table 6 in this chapter, and Figs. 1 or 2, Chapter 31. Total friction loss in the piping system is the friction drop in the most remote branch, plus the drop in the various sections of the main, plus the drop in the discharge pipe. . .. EFFICIENCY OF EXHAUST SYSTEMS The efficiency of an exhaust system depends upon its effectiveness in reducing the concentration of dusts, fumes, vapors, and gases below the safe or threshold limits.18 ' Too much emphasis cannot be placed on the necessity of testing exhaust systems frequently by determining the concentration of atmospheric con tamination at the worker's breathing level.19 Commonly accepted values Industrial Exhaust Systems 967 of threshold limits for usual atmospheric contaminants will be found -in Tables 3, 4 and 5, Chapter 8. . .. - .. ' AIR FLOW PRODUCING EQUIPMENT . In any type of exhaust system, some form of air flow producing equip ment is required to create the pressure necessary to cause the air to flow through the system to the discharge stack. The principal types of air moving equipment are centrifugal exhaust fans, disc or propeller fans, axial flow fans and venturi ejectors. Table 7. Corrosion Resisting Materials.for Exhaust Systems*. MATERIAL . Metals AClDb Acetic Chromic Hydro chloric Hydro fluoric Nitric Phos-. PHOBIC Sul- PHUBOU3 Sul phuric Dil.Jconc. Dil. Uonc. Dil. Cone. Dil.Jconc. DiL Cone. Dil. Cone. Dil. Cone. DiL Cone. Aluminum.......... Good . t Fair ., Poor. No Data Poor Good Poor ` Poor Poor Magnesium and Alloys............... No Data Good Poor No Data Poor Good No Data No Data No Data- No Data Lead and LeadCoated.'. ;........ 1 Poor Good Poor Poor Poor Poor Good Gooc Poor Moly Alloy (60 Ni--2QMo--20 Fe)................... .. Good No Data Fair No Data Poor- . Poor No Data Good Monel Metal.... Fair Poor Fair|Poor Good** Fair|Poor ' Fair Fair Good| Poor Bronze.................. Poor Good Silioon Iron........ Fair|Good No Data Fair Poor Good . Good No Data Good Stainless Steel0 Good (18 Cr-8 Ni).. Good Poor No Data Good Poor Good Poor Good Enameled Steel No Data Miscellaneous No Data Good Poor Good Poor ' No Data Good Asbestos Comp. Wood.................... Rubber................ Plastics. Good except against strong acids and ftlkaliea Some woods are decomposed or softened faster than otheis. 1 1 1 1 Poor. | | . Poor In general plastics resist weak acids and are decomposed by concentrated acid. - ? Standanl Practice Sheet No. 115 (Division of Industrial Hygiene, New York State Labor Department). ., Acid mists in air are more corrosive than as liquid in storage tank. Galvanized iron not resistant to acid. . , . j Stainless steel of (24 Cr--10 Ni) fairly resistant at low temperature for HCl and HiPOu a Under most conditions. - ' At room temperatures. ` . ` PROTECTION AGAINST CORROSION AND ABRASION Manufacturers generally provide special fans for the handling 0f various industrial wastes. When corrosive or abrasive materials'are conveyed, the fan blades and interior of the fan housing should be protected from wear. This may be accomplished by placing the collector on the suction side of the fan. Excellent protection against many corrosive acids may be obtained by lining the interior surfaces of the ducts and fans, including wheels, with rubber. . The removal of gases and fumes in many chemical plants requires that metals used in the construction of the exhaust system be resistant to chem- 968 CHAPTER 45 1952 Guide1 . ical corrosion. A list of the materials which may be used to resist the action of certain fumes is given in Table 7. Hoods and ducts, when short, may- frequently be constructed of wood and be quite effective. Rubberized paints are available and may be applied -as protective coatings in: handling such gases as chlorine and hydrochloric acid. .. - ' , . REFERENCES 'Tentative Recommended Good Practice Code and,Handbook on the Funda mentals of Design, Construction, Operation and Maintenance of Exhaust Systems, Page 21, Industrial Hygiene Codes Committee, American Foundrymcn's Association. * How to Design Exhaust Hoods, by J. M. DallaValle (Heating and Ventilating, Series of 12 articles March, 1943 to February, 1944). 8 Industrial Exhaust Ventilation in Industrial Hygiene, by Allen D. Brandt (A.S.H.V.E. Transactions, Vol. 50,1944, p. 331). 1 Fan Engineering, 1948, Buffalo Forge Co. 5 Nature of Air Flow at Scution Openings, by A. D. Brandt, R. J. Steffy and R. G. Huebscher (A.S.H.V.E. Transactions, Vol. 53, 1947). * Energy Losses at Suction Hoods, by A. D. Brandt and R. J. Steffy (A.S.H.V.E. Transactions, Vol. 52, 1946, p. 205). 7 Industrial Health Engineering, by Allen D. Brandt (John Wiley & Sons, Inc., New York). . '. 8 For more detailed requirements refer to Fundamentals Relating to the Design . and Operation of Exhaust Systems, Z9-1936 (American Standards Association). . Industrial Code Bulletin Nos. 10 and 12 (New York State Labor Department). Principles of Exhaust Hood Design, by J. M. DallaValle (V. S. Public Health Serv ice, 1939). . * Standards of the N.B.F.U. for Installation of Blower and Exhaust Systems lor Dust Stock and Vapor Removal or Conveying, National Board of Fire Underwriters. 18 National Electrical Code 1947, N.B.F.U. Pamphlet No. 70, National Board of Fire Underwriters. . : 11 The Control of Industrial Dust, by J. M. DallaValle (Mechanical Engineering, Vol. 55, No. 10, October, 1933). 18 Studies in the Design of Local Exhaust Hoods, by J. M. DallaValle and Theodore Hatch (A.S.M.E. Transactions, Vol. 54, 1932). 18 Velocity Characteristics of Hoods under Suction, by J. M. DallaValle (A.S.H.V.E. Transactions, Vol. 38, 1932, p. 387). 14 Low Velocity Exhaust Systems, by Theodore Hatch (Heating and Ventilating, October, 1940, p. 27). . 18 Tank Ventilating Power Costs Cut by Low Velocity Systems, by William B. Harris (Heating and Ventilating, July, 1942, p. 42). 18 Health Hazards in Chromium Plating, by J. J. Bloomfield and William Blum ! (U. S. Public Health Report, Vol. 43, No. 26, September 7, 1928). 17 New Data for Practical Design of Ventilation for Electroplating, by W. P. Battista, Theodore Hatch and Leonard Greenburg (Heating, Piping and Air Condi tioning, February, 1941, p. 81). Ventilation of Plating Tanks, by Allen D. Brandt (Heating, Piping and AirConditioning, July, 1941, p. 434). 18 Criteria for Industrial Exhaust Systems, by J. J. Bloomfield (A.SJH.V-E. Transactions, Vol. 40, 1934, p. 353). ' m Keeping Dust Under Control, by John M. Kane (presented to the 31st National Safety Congress, October 28, 1942, and reprinted in part in National Safety News, January, 1943). The Determination and Control of Industrial Dust, by J. J. Bloom field and J. M. DallaValle (Public Health Bulletin 917, 1935), Engineering Control of Air Contamination of the Working Environment, by A. D. Brandt (In Manual of Industrial Hygiene, U. S. Public Health Service, 1943, p. 189-266). . . CHAPTER 46 , 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 37. 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 faces. Bound 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, i.e., per pound of commercially dry solid. 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. Dry basis indicates the moisture content of a wet solid as pounds of water per pound of bone-dry solid. The advantage of using this basis is that the absolute amount of moisture loss is obtained simply , by subtracting the moisture contents before and after drying. (See definition of Wet Basis.) . Dryer efficiency is that fraction of the total heat, supplied by fuel, used to evaporate water. Overall efficiency is sometimes used to distinguish overall system efficiency from the efficiency of the drying space or evaporative efficiency. Equilibrium moisture content is that to which a given material can be dried under specific conditions of air temperature and humidity. Evaporative efficiency compares the amount of evaporation actually obtained in a dryer with that which would obtain by saturation of the air. Thefalling-rate period is that drying period during which the instantaneous drying rate continually decreases. 969 970 CHAPTER 46 1952 Guide f- 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 at 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. Thefunicular state is that condition in drying a porous body when capillary suction 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 Wight or 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 rum-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 a 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 dryers may be shown to differ fundamentally with respect to the method used for transferring heat to the solid.' In general, heat must flow first to the outer surface of the solid and then into the interior. An important ex ception is drying with high frequency electrical currents where heat is generated within the solid, producing a higher temperature at the interior than at the surface, and consequently, causing heat to flow from inside the solid to the outer surfaces. Mass transfer in drying occurs as liquid or vapor flow, or both, within Industrial1Drying Systems 971= 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 on 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 easier to establish and the results have greater immediate application hr dryer design and operation. Internal Mechanism of Liquid Flow. Internal liquid flow may occur -by several mechanisms, depending on the structure of :the solid. Several mechanisms of flow are as follows: . -. 1. Diffusion in continuous, homogeneous solids. 2. Capillary flow in granular and porous solids. 3. Flow caused by shrinkage and pressure gradients. . 4. Flow caused by a vaporization-condensation sequence. 5. Flow caused by gravity. . ' 6. Flow caused by an electrical potential, electro-osmosis. 7. Flow caused by temperature gradients, thermal diffusion '.' Although more than one of these mechanisms of flow may be effective at one time, only one predominates as a rule at a given time in a solid during drying. However, a different mechanism may predominate at a different time in the cycle. The mechanism of moisture flow is usually established experimentally from a study of moisture gradients. External Variables. The principal external variables involved in any drying problem are: temperature, humidity, air flow, state of subdivision of the solid, agitation of the solid, method of supporting the solid, and the contact between hot surfaces and wet solid. All these variables do not necessarily occur simultaneously in one problem. ' 972 CHAPTER 46 1952 .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. 2, it is shown by a straight line of constant slope dW/dd, which becomes a horizontal line on the rate curves in Figs. 3 and 4. ' Industrial Drying Systems 973 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 Fig. 4. Rate of Dbyino, vs. Time 8 to convection, the surface temperature will be constant at some value between the air temperature and the wet-bulb temperature. This higher temperature in turn produces a higher constant rate of evaporation. In those dryers in which heat is transferred to a wet solid by conduction through hot surfaces, and heat transfer by convection is not a factor, the wet surfaces approach the boiling point temperature rather than a wetbulb temperature. When all the heat for evaporation in the constant-rate period is supplied by a hot gas, a dynamic equilibrium is established between the rate of heat transfer to the material and the rate of vapor removal from the surface. This equilibrium between heat and mass transfer rates can be expressed as follows: dtp htAbt ... S- = -- " k'A*v ... (1) where T? = drying rate, pounds of water per hour. 97 4 CHi A.PTER 46 1952 Guide At: = 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 t,, Btu per pound. . fc = mass transfer coefficient; pounds per (hour) (square-foot) (atmosphere)V ,. a! = (t, -- l.) = temperature difference between air and surface of evaporation, , Fahrenheit degrees. , . ' ! = air temperature, Fahrenheit.' '. '" U = temperature of surface of evaporation. Fahrenheit. Ap = (p. -- p.) = vapor pressure difference, atmospheres, p, = vapor pressure of water at U, atmospheres. . ' p, = partial pressure of water vapor in air, atmospheres. : When ht = he, the coefficient of heat transfer by convection only, then under equilibrium conditions becomes ta, 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 + 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 Centigradedegrees. , Effect of Air Velocity. The principal effect of air velocity is on hc and ke, 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 ? . A, = 0.0128 G0-* ; (2) where ' Ac = 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: , . ^o0.0128G0M(<>_u (3) where . i,, = wet-bulb temperature of the drying air, Fahrenheit degrees. . . Heat transfer coefficients, rather than mass transfer coefficients, should be used to estimate drying rates, because heat transfer coefficients are generally more reliable, and, unless the temperature of the drying surface is measured, it must be calculated from heat transfer considerations before mass transfer coefficients can be applied for drying-rate predictions. The assumption that the surface of drying is at the wet-bulb temperature of the air, introduces a more serious error in the computation of mass transfer than of heat transfer. '' Determination of True Surface Temperature. Frequently, radiation and conduction are of sufficient magnitude to cause the temperature of evap oration to exceed the wet-bulb temperature of the air. When this occurs, it is necessary to estimate the true surface temperature in order to calculate Industrial Drjfing Systems 975 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-Circulation 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 milking 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 and5, cylindrical particles with through-circulation of air : ,. where aw dW _ 0.42aG-ss(AH)m 0.37c.a(?"Af d0 Dp41 Xp.D",-41 v .. ' ' .' \ " . ............... constant rate, pounds of water per (hour) (pound of dry stock). ,,, W ' . a =. drying area, square feet per cubic foot of bed yolume.. . . G = superficial mass velocity, pounds of dry air per (hour) (square foot), m = 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 hunudity. cbrres- ponding to the wet-bulb temperature of the drying air).' ~ = bulk density of dry granular bed, pounds per cubic foot. : Dp = average diameter of particle, feet. Aim = logarithmic mean difference between temperature entering and leaving the bed and the wet-bulb temperature, Fahrenheit degrees. c8 = humid beat, Btu per (pound of dry air) (Fahrenheit degree). X = latent heat of evaporation, Btu per pound. Equation 4 applies w;hen the Reynolds number DpG/n js greater than 300, where /x 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 drying, evaporation rates of liquid drops must be estimated.' 'Below a value of Reynolds number (DpG/u) of 10 for spherical particles, tbe: heat ' transfer coefficient across the gas filin surrounding the drop is given by ' (5) where A = film heat transfer coefficient, Btu per (hour) (square foot) (Fahrenheit de-. gree). - ki = thermal conductivity of gas film, Btu per (hour) (square foot) (Fahrenheit degree per foot). . Equation 5 is applicable when the Reynolds number for liquid drops is less than 10. Drop diameters are almost always less than 500 microns, and usually in the range of 20 to 150 microns. ' The rate of evaporation of drops may be expressed in tenias of heat transfer or mass transfer. In terms of heat transfer, the evaporation rate is given by the equation: , ,, . ? , . . 976 CHAPTER 46 1952 Guide ^0.-0 da x (6) where dw evaporation rate^ pounds per hour. de A'similar expression based, on mass transfer is da 2irMdiDp (p. -- P) dB RT (7) where . . M -- molecular weight of the diffusing vapor. d = 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). pi = vapor pressure at the particle surface corresponding to the liquid tempera ture, atmospheres. p = 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 (i.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: .. IfXpdlp 12*/(* - t.) . (8) where e = time, hours. W = water content 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 (ta -- t,) 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 plXKTU* - (Pp*)*! 8*.(!.-,) ,Qs ' where ' >L = density of the evaporating liquid, pounds per cubic foot. Dti = drop diameter at the start of evaporation, feet. Dp, = 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. When the temperature of the drying air is maintained above the boiling point of the liquid being evaporated, or when superheated vapors are used for drying, the usual equations for mass transfer, expressing rate of evaporation Industrial Drying Systems 977 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.1 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 (th - t.) (10) where - q = rate of heat transfer, Btu per hour. V = overall heat transfer coefficient based on the temperature difference between the heating medium and the product, Btu per (hour) (square foot) (Fahren heit degree). fh = temperature of the heating medium, Fahrenheit degrees. . . i, = temperature of the solid, Fahrenheit degrees. 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)n (11) The FaUing-Rdte Period. In the discussion of the periods of drying, it was shown that the drying process is discontinuous, consisting of a period of a constant rate of evaporation and a period'in which the rate 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 tent is less than the required final moisture content, the constant-rate period will constitute the whole of the drying process. On the other hand, if the initial moisture content is less than the critical moisture content, as -978 CHAPTER 46 1952 Guide 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- unsaturated 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 froih a progressively decreasing wetted surface. With the surface no longer completely wetted, dry portions of the solid protrude into the air filin, 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 line 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 falling-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: _ j V -Wo-W. , 1 e-Md(W!Z.)l ii _L j-iKdd/!!)' J- . . . 9 25 J (12) where . ... ' W, Wo, Wo = 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 . ::i / - external conditions, respectively, pounds of water per pound of i `r 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 = _ g-liloltLy Wo - W. (13) Industrial Drying Systems 979 From Equation 13 an expression for the rate of drying may be derived to give '' : dW de ' (14)' where dW/di = 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 -- IF.), the liquid diffusivity d, and that the time of drying varies as the square of the material thickness. However, Equation 14 holds only when (IF -- W.)/(IFo -- IF.) <0.6. When this ratio-exceeds 0.6, the curve.of drying rate 8..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: , (15) where K is a function of the constant.rate as follows: .. (dW/de)o (Wo - 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 (dWfdOc) the value of K becomes ., . . ` : hdt. - l.) K= PoL\(Wo - W.) (17) and hence, the falling rate for-this case is given by . . ; V.' fdw\ _ ~ - w.) /; \d8jt. pjMWo-Wo) :, (18); For materials obeying Equation 18, the drying time varies directly as' the thickness. When, the surface temperature in the constant-rate, period is at the wet-bulb temperature, tv can be substituted for fc 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: : :r 1. Diffusion law . . . . .. . 2. Proportional-to-thickness law PoLk(Wo - W.), (Wo - WA ~hito - u) ^\w~rwo ) (20) 980 CHAPTER 46 1952 Guide / - -r- 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 drying. When through- circulation drying is involved, the appropriate 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 . 0^7c.nGJa(At)m p,XDpo(IF. - WO ( (IF.) (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. Appboximate Classification of Materials Most Likely to Obey Equations 19 and 20 Materials obeying equation 19 Materials Obeying Equation 20 1. Singe-phase solid systems such as 1. Coarse granular solids, such as sand, soap, gelatin, glue. paint pigments, minerals, etc. 2. Wood and similar solids below the fiber 2. Materials in which moisture flow occurs saturation point. . at concentrations above the equi 3. Last stages of drying starches, textiles, librium moisture content at atmos paper, clay, hydrophilic solids, and other materials when bound water is pheric saturation, or above the fiber saturation point. being removed. 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 in 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: 0t = 9c + 01 OF. - TFJxLp. pJMWo - W.) Wo-wr hiio-t.) + UU-Q OZW-Wo =B Wo Wo + log. Wo W - W.l Wo J (22) Industrial Drying Systems 981 where : , - n poB\(Wo -- We) 1' ~ ht(t. - U) = K' ' , 0t = total drying tiine, hours. . . . .0. = drying time for constant-rate pepod, hours. . , 0i = drying time for falling-rate period, hours. W0 = initial moisture content, pounds per pound of dry solid. IF. = critical moisture content, pounds per pound of dry solid. IF. = equilibrium moisture content, pounds per pound of dry solid. IF = moisture'content at time 0t, pounds per pound of material. ' hi = total overall heat transfer coefficient Btu per (hour) (square foot) (Fahren- . heit degree). . to = air temperature, Fahrenheit degrees. . to -- temperature of surface of material, Fahrenheit degrees. . 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 , . Wq -Wo IF. - TF.~I + log, Wo - Wo W - 1F.J (23) where B, 2.7p,\DJ>(Wo - IF.) c,aG-M(Al)m 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 and 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 vapor in the surrounding air, and a decrease in the water vapor content will decrease the amount of equilibrium bound water. Water so retained by a solid in equilibrium with the humidity of the surrounding, air, is .designated as the equilibrium moisture content. Such moisture may be held as adsorbed surface films or condensed in fine capillary structures at reduced vapor pressure. . ` . The equilibrium moisture content varies with the temperature and humidity of the surrounding air. Consequently, any correlation of equili brium moisture content should take these two factors into account. How ever, at low temperatures, e.g., 60 to 120 F, a plot of equilibrium moisture content vs. percent relative humidity, expressed as 100 (p/p.), is essentially independent of temperature. Such a plot usually results in a curve of double curvature with a point of inflection (see Fig. 5). The equilibrium moisture content at A given relative humidity is not 982 ' CHAPTER 46 .. 1952-Guide independent of temperature for all temperature ranges. As the tempera 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 hygroscopic 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 of 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 hygroscopic material may be determined in a number of ways. The requirement for any method is a Industrial Drying Systems 983' conditions of- air humidity and'temperature.- Drying costs1'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 until a constant weight is obtained. The moisture content at this final weight represents the equilibrium moisture content for the particular relative humidity involved. The value of equilibrium moisture content so ob tained will'depend on 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 or lower than the equilibrium value. The equilibrium moisture content reached by losing moisture, i.e., by drying, is generally higher than that 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 specific vapor by the air or gas stream. Likewise, two processes are involved in; . the 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' rate; and (2) the calculation of the, heat, and air. quantities required; The. first estimates concerning drying time have been considered in the first, part of this chapter. The second calculations are based on the use of the- psychrometric chart, Fig. 6. ............... ,. . . In drying, the humidity chart finds its greatest utility in analyzing-the operation of existing dryers, in making design calculations, and in.checking calculations of air quantities.. It is equally useful in interpreting the humidity-temperature relations within the dryer. The adiabatic cooling lines on the humidity chart, indicate the relation between the temperature and the humidity which are present in air passing through an adiabatic dryer, i.e., one in which all of the sensible heat given up by the air in cool ing is used to evaporate water from the wet stock. Referring to the section of the humidity chart shown in Fig. 7, where AB is one adiabatic satura tion line, it follows that air entering an adiabatic dryer at temperature ti 984 CHAPTER 46 1952 Guide and a humidity. Hi will cool, following this cooling line toward- point A. Air leaving -with a humidity- Hj will consequently have cooled to tj, the wet-bulb temperature of the air throughout -the dryer being ti,. When heat is.lost to the surroundings, the operation is somewhat lower than tj, so that the actual, humidity-temperature relation is represented by the line Bb, having less slope than the adiabatic saturation line. The .ratio (ti -- t2>/(ti -- ta) 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 Hj 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 line such as Be having a positive slope. , ........ Industrial'Drying Systems 985 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.' 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 for tray drying of any material in the constant-rate drying period.. It does not apply to rotary or through-circulation drying. ... ' . A curve for correcting the air velocity in any given problem is incor? porated in Fig. 8. This curve is based on the variation of drying rate with 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. to, determine drying times for design purposes by means , of pilot tests, however, when tests are not feasible, diying times may often be estimated approximately .from Equations 22 and 23. . The following nomenclature wifi be used in the discussion of design cal culations: . H = humidity ratio of air, pounds of water vapor per pound of dry air. . Nt = pounds of dry air supplied to the dryer per unit of time. . , S = pounds of stock dried per unit of time in a continuous dryer. . S' = pounds of stock charged per batch to a discontinuous dryer. . 0 - time, hours. ' .' Q = total heat supplied to the drver, Btu . 986 CHAPTER 46 1952 Guide t = air temperature. Fahrenheit degrees. . .-ip ... ; -!; t' = stock temperature, Fahrenheit degrees.; : , i" = average stock temperature over short time interval, in.a batch.dryer, Fahr- - .. , enheit degrees. ...... . .. . . . ........, .. wet-bulb temperature; Fahrenheit degrees.- , . ; , ... ...... *i.,= specific heat of.the stock, .Btu perpound. . . . .. . - .Qro,^= total.radiation and conduction losses, Btu per hour.. .; . .- IF =. pounds .of water per pound of dry stock. ., .' x =, heat of`evaporation of water, Btu per pound. ' " . ... . V c,'.= humid heat of air; i.e., heat necessary to raise 1 lb of dry air' + H lb of steam I F deg. '' " Subscript (l)..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 : . N. (Ht -- Hi) =.S(Wi -- Wi) (24) where Ht is constant. ' - In discontinuous dryers, the drying operation is given by the equation ,` dW N.(H, - = S' -- (25) where Ht is a variable during a portion of the cycle. In the continuous dryer, the heat consumption per unit time is ? = N^(t, - h) + AT.(X, + it - ft){Ht - Hi) + S(t', - <',)(*, + IF,) + Qn (26) o -- .. ' Equation 26' assumes continuity of operation1 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 f, t' and H may be employed, provided the third term of the right hand member of the equation is modified to read: S'(ft - ft) (si - Wi) . and in the second term t't be replaced by ' .. '. ' >, -h ft ' 2 .. .'. Theoretically, these periods should be .very short and the equation intejgrated. Practically, the error introduced by using a small number of long periods and employing average values of the variables over each, is nbt serious. The evaluation of'Equation 25 may be approxiniated'in a similar manner. The first term of the right hand member of Equation 26 represents heat lost as sensible heat in the effluent air. In many- drying operations this becomes excessive. Each pound of air supplied should remove the maxi mum amount of moisture. This is best accomplished by bringing the air into contact with the stock with sufficient intimacy so that the air leaving Industrial Drying Systems 987 the dryer is saturated, or nearly so. Counter-current,- as-against;parallel, flow-of.'air and stock gives rise to optimum operating conditions, resulting in a minimum quantity of air required (iV), and a corresponding minimum loss, as sensible heat, in the exit air. Similarly, continuous operatiori 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- Fig. 9. Changes in Aib Dubing 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 losses from the dryer are those of radiation and conduction from the hous ing, 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 (n> or the temperature determined by previous test). As the air evaporates moisture, it cools along the constant wet-bulb line. BD to point C. The difference between the moisture content of air at B and at .C represents the moisture pick up of the air. The maximum possible pick up from B to D is never achieved in practical dryers, the actual pick up being anywhere from 10 to 75 per cent of the maximum. :. < In order to conserve heat and to control the wet-bulb temperature at which the drying takes place, recirculation is used. The process is shown on Fig. 9. The outside air at A is mixed with recirculated air until the moisture level is raised to the desired point. The mixture is represented at point M, the heaters heat the mixture to the desired dry-bulb tempera ture at point S. The moisture is picked up from S to L. Point'L is the condition at which air is exhausted. = . : . 988 CHAPTER 46 1952 Guide - 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 . .. ,'ln 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 Hi. Where experimental data are lacking L may, be approximated from Regain Tables (see chapter 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. . Fio. 10. Temperature and Moisture Conditions in a Tunnel 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 vari ables involved, it is generally not possible to select S except oh 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 A L. 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. 1 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 of 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. 1 Drying systems can also be classified, according to the method of product handling, as batch operation, semi-continuous and continuous. Radiant Drying 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. Industrial Drying Systems 989. 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 (hying 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. 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. II,8 flat surfaces, open kettles and immersioh 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 material 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 micro-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 in a high vacuum chamber connected to extremely low temperature con densers. The water is removed by vaporizing from the solid directly to the gas without ever becoming liquid. Convection Drying (Direct Dryers) A limited amount of convection drying takes place in almost any dryer such as those described in the preceding paragraphs, However, to be 990 CHAPTER 46 1952 Guide Industrial.Drying Systems `991 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: : Itotary Dryers. These dryers are cylindrical drums which cascade the material being dried through the air stream. (See Fig. 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 diyer 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 VCT.MATtftUL Fio. 12. Cross Section and Longitudinal Section Through Circulation Dryer" 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 r,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 tures may run from 250-300 F up as high as 1200 F. Drying times are very short because of the minute particle size. Particles as small as 5 to 10 microns are formed in spray dryers. The dry powder is separated from the air by cyclone separators which are sometimes followed by cloth bags or scrubbing towers. Because of the high inlet temperatures and the relatively large volume of air required, the efficiency of the spray dryer is not too good and, conse quently, is seldom used for dilute solutions (less.than 30 percent solids). Fig. 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 1 1 'I**" Q [s Fig. 14. Section op Continuous Dryer, Blow-Through Type 992 CHAPTER 46 1952 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.' 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 1: Assume 900 lb per hour of ceramic powder is to be produced. The powder has a specific heat of 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 of 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 highest desirable product temperature. Experience also indicates that a drying time of 45 min is possible at about 160 F dry-bulb and 100 F wet-bulb. Fig. 16. Continuous Belt Dryer for Ceramic' Powders Industrial Drying Systems 993 Step 1: Let x = pounds moisture at final condition. Then, . = 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 x895.5 + x 0.19 or, x = 210 lb. ' The weight of moisture to be removed is 205.5 lb per hour, and wet material enter ing dryer is 1105.5 lb per hr. . .. Step 2: Previous tests indicate that a \ 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 (} hr) drying time, the dryer holding capacity will have to be 830 ' ` 1105.5 X 0.75 = 830 lb of wet material or =, 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 = 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.10 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 Kg. 6) is 0.028 lb per pound of air. Make-up air will be assumed at 80 F dry-bulb and 72 F dew-point (summer weather), or a humidity of 0.0168 lb per pound of air. The pick-up is therefore 0.0280 -- 0.0168 or 0.0112 lb per . 205 5 : . . pound of air. Then ^ q ~ ^ = 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 of.air per min. Hence, .. . Make-up air = 46 percent Recirculated air = 54 percent Step 4: Although the drying condition and drying rate should preferably be de termined from experience or test results, the drying conditions can sometimes be estimated if the regain characteristics of the product or a similar product are known. In this case the regain characteristics of clay could be used as a guide: Inspection of regain data for typical clays indicates that at about one-half of one percent the vapor pressure of the moisture in the product is about 0.7 in. Hg less than the vapor pressure of free moisture at the product temperature. An assumption is made that the product temperature approximates the air wet-bulb temperature. If an assumption is made regarding the percent recirculated air the desired vapor pressure in the dryer can be estimated. For example assume a use of 46 percent outside air or 307 lb per min. Then 2055 the moisture pick-up -- gQ y gqy = 0.0112 lb per pound of air, with a consequent total of 0.0168 + 0.0112 = 0.0280 lb of moisture per pound of air in the leaving outside air, which has about 1.25 in. Hg vapor pressure. This is assumed to be the vapor pressure of the moisture in the product, and thus the vapor pressure of free water at product temperature can be 1.25 + 0.7 = 1.95 in. Hg. The temperature corresponding to 1.95 in. Hg is 100 F, and thus the air wet-bulb can be.estimated to be 100 F. At 100 F wet- bulb temperature and 0.028 lb moisture per pound of air, the dry-bulb temperature is 160 F. Obviously, the assumed percentage of recirculated air affects the results, and therefore it is important that it be based on experience. About 50 percent recircula tion is reasonable for the type dryer considered in this example. ' 994 CHAPTER 46 1952 Guide Step 5: The pick-up of moisture per pound for the total air circulated is 205.5 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 and 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 + 0.45 ^0,028 +2 0 0229^ = 0.251; 1, = 80 F; f. = 160 F; t,' = 100 F; X = 1100 (approx.); W = 0.005 lb; i = 0.22. Q = 18420 (0.251) (160 - 80) + 18420 (1100 + 160 - 100) (0.028 - 0.0168) + 900 (100 - 80) (0.22 + 0.005) + Qn . = 609,000 Btu per hr + Qn The heat input requirement is therefore 609,000 Btu per hr plus radiation and con vection losses (.Qn) 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 radi-. ation and conduction losses are a large percentage of thetotal. 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 cir culating duct would maintain constant desired wet-bulb temperature, by simultaneous positioning of three sets of dampers in. the makeup air, the exhaust air and the recirculated air'ducts. . . LETTER SYMBOLS USED IN CHAPTER 46 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). r. = humid heat, Btu per (pound of dry air) (Fahrenheit degree), d = diffusivity of the liquid or vapor, square feet per hour, jD0 = average diameter of particle, feet. Dpi = drop diameter at start of evaporation, feet. Dp = drop diameter of dry particle, feet. e -= Naperian base of logarithms - 2.718. . G = mass velocity of dry air, pounds per (hour) (square foot). AHm = logarithmic mean of inlet and outlet humidity driving force across the air film adjacent to the particle through which the water vapor diffuses, pound per pound. (The surface humidity is taken as the humidity cor responding to the wet-bulb temperature of the drying air). Hi = humidity ratio of entering air, pounds of water vapor per pound of dry air. _ Hi = humidity ratio of leaving air, pounds of water vapor per pound of dry air. h = film heat transfer coefficient, Btu per (hour) (square foot) (Fahrenheit degree). A, = coefficient of heat transfer by convection, Btu per (hour) (square foot) (Fahrenheit degree). , h, = coefficient of heat transfer by radiation, Btu per (hour) (square foot) (Fahrenheit degree). At = total gas film heat transfer coefficient, Btu per (hour) (square foot) (Fahrenheit degree). . K = a constant (a function of the constant drying rate). Industrial Drying Systems 995 kt = gas film thermal conductivity, Btu per (hour) (square foot) (Fahren- . heit degree per foot). .. ti = mass transfer coefficient, pounds per (hour) (square foot) (atmosphere). ; L = material thickness, feet. . . M = molecular weight of the diffusing vapor, ' -- dry air supplied to the dryer,.pounds per hour. Ap = p. -- p = vapor pressure difference, atmospheres. . p. = vapor pressure of water at f,, atmospheres. = vapor pressure at.the particle surface corresponding to the liquid tem perature, atmospheres. Pi = partial pressure of water vapor in air, atmospheres. ' p = vapor pressure of liquid in the drying medium, atmospheres. : Qn = 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. * = specific heat of stock, Btu per pound: ' T = absolute temperature of the gas, Fahrenheit degrees. U = air or gas temperature, Fahrenheit degrees. , lh = temperature of the heating medium, Fahrenheit degrees. t, " temperature of particle, solid or surface of evaporation, Fahrenheit degrees. t, = wet-bulb temperature of drying air, Fahrenheit degrees, ti = entering air temperature, Fahrenheit degrees. <i = leaving air temperature, Fahrenheit degrees. ti -- entering stock temperature, Fahrenheit degrees. h' = leaving stock temperature, Fahrenheit degrees. t" = average stock temperature over short interval of time, in batch dryer (ft" = entering, ti = leaving) Fahrenheit degrees. Af = (U -- f.) = temperature difference between air and surface of evapora tion, Fahrenheit degrees. . Afm = logarithmic mean between temperature entering and leaving the bed. and the wet-bulb temperature, Fahrenheit degrees. . U = overall heat transfer coefficient, Btu per (hour) (square foot) (Fahren heit degrees temperature difference between heating medium and prod . uct). ' W = moisture content on dry basis at any time 0, pounds of water per pound . W,, = critical moisture content, pounds water per pound dry material. . We = water content, dry basis, of the drop as it enters the drying chamber, . pounds per pound of dry solid. IFo = moisture content at equilibrium with external conditions, pounds per ; pound dry material. Wo = initial moisture or moisture content at start of difTusional period, pounds per pound. u> = pounds of water. dW de = drying rate, pounds of water per (hour) (pound dry material). ' = constant drying rate, pounds per (hour) (pound dry material). = falling rate, pounds water per (hour) (pound of dry stock). dw de = drying rate or rate of evaporation, pounds of water per hour (Eq. 1). e = time, hours. Bo = drying time for constant rate period, hours. Bt = drying time during falling rate period, hours. Bt = total (bring time, hours. X = latent heat of evaporation at Btu per pound. . M = viscosity of the air stream, pounds per (hour) (square foot). Pc = density of evaporating liquid, pounds per cubic foot. p = bulk density of dry granular bed, density of dry particle, pounds per cubic foot. .Vr. 996 CHAPTER 46 1952 Guide REFERENCES 1 Drying, by W. R. Marshall, Jr. and S. J. Friedman, Perry's Chemical Engineers' Handbook, McGraw-Hill Book Co., Inc., New York, 3rd Edition,. 1950. Indicated material supplied by W. R. Marshall, Jr. and S. J. Friedman,.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. S-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 O. A. Hougen (Transactions, American Institute of Chemical Engineers, 1942). . 6 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). . Mass Transfer in the Flow of Gases through Granular Solids Extended to Low Modified Reynolds Numbers, by C. R. Wilke and O. A. Hougen (Transactions, Ameri can Institute of Chemical Engineers, 1945). 7 Limitations of Diffusion Equations in Drying, by O. A. Hougen, H. J. McCauley and W. R. Marshall (Transactions, American Institute of Chemical Engineers, 1940). 8 What the Air Conditioning Engineer Should Know About Drying (Heating and Ventilating, December, 1942). 8 Spray Drying, by. Ben B. Fogler and Robert V. Kleinschmidt (Industrial and Engineering Chemistry, December, 1938). ' " 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.V.E. Tbanbactiorb, Vol. 24,1018, p. 25). 'Thermodynamic Properties of Moist Air, by John A. Goff and S. Gratch (A.S.H.V.E. Transactions, Vol. 51, 1045, p. 125). . Factors Influencing the Performance of Rotary Dryers, by C. F. Prutton and C. O. Miller (Transactions, American Institute of Chemical Engineers, Part 1, February, 1942; Part 2, August, 1942). ( Drying of Solids by Through Circulation, by W. R. Mni-shali 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. Mets, G. B. Ridley, C. O. Lavett, D. J. Van Marie (Industrial and Engineering Chemistry, May, 1921, pp. 427-450). - .. Studies in Rotary Drying, I and II, by S. J. Friedman and W. R. Marshall, Jr. (Chemical Engineering Progress, 1949). Symposium on Drying (Industrial and Engineering Chemistry, 1938). Principles of Drying Lumberand Humidity Diagram, by H. D. Tiemann (Forest Service Bulletin, 104,1912). The Diying 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 (Food 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 1. R. Berkness (Wood Products, Vol. 45, 1940, P. 12). Development of the Unit Operations of Chemical Engineering: Drying, by T. K. Sherwood (Chemical & Metallurgical Engineering, Vol. 42, p. 214). . _ The Spray Dryer--Its Possibilities in Industry, by D. W. Biochgno (Food Manufacturing, Vol. 19, June, 1944, p. 195). . ._ ,, Mechanism and Rate of Drying by Near-infra-red Radiation, by L. E. Stout, K. J. Caplan and W. G. 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 Arsdel (A.8.H.VJ2. 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. Ross Company. ' Elements of Chemical Engineering, by Badger and McCabe (McGraw-Hill Co., 1931). Fan Engineering, Buffalo Forge Co. Die Trockentecnnik, by M. Hirsch (Julius Springer, Berlin, 1932). Kiln Drying of Lumber, by H. D. Tiemann (Lippincott, 1920). CHAPTER 47 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 pas1 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 using covers designed to increase gravity air circulation, and to direct the warm air from firmed heating surface along cold outside walls and car windows. In some new cars, wall convector panels are used and extend the full length of the car, with air intakes along the floor and outlets at win dow 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 the panel duct increases air flow and improves heating surface efficiency. Steam may be used directly in finned tubing, or steam may be used to heat a liquid (usually a mixture of water and diethylene glycol) which is 997 998 CHAPTER 47 1952 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 long 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 29.) 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 7. 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 is 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 to the entire train. Recently there have been installations in which a Dieseldriven alternator is mounted on an individual passenger car to supply the 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 in 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 999 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 of metal, wool, cloth, spun glass, hemp, paper, hair and wire screen. Most filters have a viscous coating of oil for greater cleaning efficiency. Some types may be cleaned, re-treated, and re-used, while other types are dis carded when dirty. Applications are also being made of electric precipita tion for air cleaning. In this system the coarser particles are removed 1000 CHAPTER 47 1952 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 29 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 in 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 give 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 1001 STREETCAR AND TROLLEY COACH HEATING AND VENTILATING Streetcars and trolley coaches present a special problem in the maintonance 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 his 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 modem 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. The best results 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 ' withstand the vibration present on transportation equipment, is used. Automatically operated dampers are used to control flow of heated air to the passenger space, or to direct heated air to the atmosphere. An automat ically operated rheostat or multi-point switch is used to vary the speed of the ventilating fans. Recent control system applications employ one thermostat to operate both heating dampers and ventilating fans in a modulating or graduated manner, with a compensating thermostat in the heat supply duct to correct for wide fluctuations in temperature of airleaving the resistors. Ventilating fans are usually stopped or operated at lowest speed during the heating cycle, and then their speed is gradually increased as the car temperature rises above the heating-cycle control point. 1002 CHAPTER 47 1952 Guide ' I' PASSENGER BUS AIR CONDITIONING The passenger bus designed for urban transportation operation presents a greater problem to the designer of heating systems than does the interurban 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 surfatee 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 atmospheric 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 is 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. 1003 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 engine. 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 bpses 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 enginedriven 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 is 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 has progressed from comparatively simple systems to highly complex multi-purpose designs. The attendant control problem has become cor respondingly complex. On older, non-pressurized planes, the heating sys- , 1004 CHAPTER 47 - .1952 Guide 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 im 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 a 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 1005 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 supercharged-air inter-cooler would be in full closed position, so that none of the heat of compression would be removed, and the air would 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 rim 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 lull cold position, i 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, mid adjust ing the cabin-pressure relief valve setting, by means of a cabin pressure se. lector, to maintain the desired cabin pressure;1 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 stat and to vibration experienced on all airplanes. All modem controls use some type of bridge system with temperature sensitive resistors as sensing elements. Iii some types of controls, the bridge system feeds a sensitive balanced relay, which in turn runs a modulating motor or controls an on-off power relay. A recent sensitive and quickly responding type uses an electronic amplifier, which in turn controls a two-phase motor, or, through relays, controls a d-c motor, or merely closes and opens a power relay for on-off applications. . In addition to extreme speed and accuracy which are required of all air craft temperature controls, they must be able to operate under great ex- 1006 CHAPTER 47 1952 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-heating due to failure of air supply, or any other cause. Also, there should-be safety devices to shut off fuel in case of flame failure. -' _ On the latest high speed jet airplanes, the temperature control problem is still more severe than on the latest transports; as in addition to the accuracy required, 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 bn 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 oh 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, such as steel, copper and brass, is many times the value of building material used ashore. The length of ducts between heat sources and fans necessitates extra duct insulation. Hull insulation must be of high quality, with Transportation Air Conditioning 1007 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 Design Temperatures 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 A R.H. Effective Temp. F .% 80 50 80 55 85 50 F 73-74 73+-74J 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 as close as possible to each zone. Where a reheater serves only one space, it 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 ' The prime purpose of machinery space ventilation is to maintain a habitable temperature for the operating personnel. It is more practicable to use spot cooling of personnel at working areas than to attempt to obtain uniform ambient temperature. The permissible temperature rise (above * See Ventilation and Heating of Maritime Commission Ships, by J. W. Markert (Heating and Ventilating, Feb. 1943, p. 333). . 1008 CHAPTER 47 1952 Guide 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.1 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. 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 id 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 will 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 from Transportation Air Conditioning'. y ` 1009 45 to 60 F. Ventilation should be. sufficient to change the air in the spaces, ini 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 37). 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 (Freon) compressors. Ships requiring in excess of approximately 125 tons Of refrigeration generally - use centrifugal compressors: Steam jet refrigeration has proven satis factory on several large foreign liners and is being seriously, considered in this country 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 well established.. All passenger staterooms, except steerage and third 1010 CHAPTER 47 1952 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 spacesare usually air conditioned. ' All messrooms, recreation rooms, officers' offices, crew's inboard rooms, and those having fixed portlights are usually air conditioned on passenger vesgels. 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 f6r 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, a 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 just described, except that each room is provided with an induction unit (floor type where possible) which reheats the primary air supply. Control of Transportation Air Conditioning 101i Fig. 1. .Arrangement of Aib Conditioning System with Central Supply Equipment and Individual Hot Wateb Room Reheatebs .' heating coil in the induction uhit 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 sub master 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. However, if power is available, and suitably strong duct construction and adequate sound absorbing facilities are provided, high velocity systems may be used. BIBLIOGRAPHY . Railway Passenger Cars . Report on Performance and Coat of Operation of 1037 Internal Combustion Engine Mechanical Compres- emn Equipment for Air Conditioning Railroad Passenger' Care, by Division of Equipment Research, Aw cxatum of American Railroads, May 1,1937. ' 1012 CHAPTER 47 1952 Guide _ Report on Relative Performance of Air Filters, by Mechanical Division, Association of American Rail roads, January 15, 1938. .... - . Air Conditioning of Railroad Passenger Cars, by L. W. Wallace and G. G. Early, Jr. (A.SJd.E. Trans actions, November. 1937). ' Passenger Car Cooling Methods, by Kenneth Cartwright {Refrigerating Engineering, February, 1936. d. 83 and March, 1936, p. 158). . . _' Diesel Drive for Passenger Air Conditioning, by J. R. Horhaday (Refrigerating Engineering, March, 1942 p. 139). _ Railroad Air Conditioning, by Gordon T. Wilson {Refrigerating Engineering, May, 1943, p. 323). Railway Air Conditioning, by M. R. Bastin (Railway Elec. Engr., August-December, 1942). Head-End Power for Railway Cars, by F. L. Sahlmann and E. M. Bill (Railway Elec. Engr., May, 1939). -Head-End Power for Streamlined Passenger Trains, by J. D. Loftis (A.S.MJ2. Raleigh Section, October 26 1846)-.' * P.C.C. Car Ventilation, B-3697 Westinghouse Electric Corp., September,' 1946. . . Buses and Automobiles Bus Heating, by E. T. Todd and F. O. Gadd (Heating and Ventilating, Dec. 1946 p. 83). Air Conditioning of Automobiles and Buses, by. L. W. Child (Society of Automotive Engineers Journal, June, 1938): Bus Air Conditioning, by Jerry Hicke (Heating, Piping and'Air Conditioning, October, 1938, p. 639). Bus Air Conditioning, by A. J. Mallinckrodt and Lara Hanson (Refrigerating Engineering, June 1939, p. 388). .- Problems in Air Conditioning Automobiles. by F. J. Linsenmeyer (Society of Automotive Engineers Jour nal, July, 1939). . ' . . Airplanes " .v Comfort in High Altitude Flying, by D. W. Tomlinson (A.S.H.VJD. Tbanbactionb. VoL 47, 1941, p. 57). Heat Exchangers for Aircraft, by Arthur J. Hess (Refrigerating Engineering, September,4944,jp. 192). Heat ing and Ventilating for Transport Airplanes, by B. M. Brod (A.8H.V-E. Tranbactions,.Vo1. 52, 1946). Com- fortization of Aircraft, by Albert A. Arnhym (Pitman Publishing Corp.*, New York, 1945). ~ - Refrigeration for Air Conditioning Pressurised Transport Aircraft, by & L. Messinger {Heating and Ven tilating, January, 1946, p. 63). . -- ' .. ' . Ships * The Ventilation of Ships, by R. McDonald (Journal of the Institution of Heating and Ventilating Engineers. (British) October, 1939). '. Ventilation and Air Conditioning of the S. S. Panama (Heating and Ventilating, September, 1939, p. 47). Air Conditioning the New Mauretania (Heating. Piping and Air Conditioning, July, 1939, p. 431). . . * Trying, Ventilating and Air Conditioning on Shipboard, by J. H. Clarke (Heating, Piping nnA Con ditioning, August, p. 467; September, p. 529; October, p. 610, 1940). * `- Care of Cargo at Sea, by O. D. Colvin, W. H. E. Hahne, and M. R. Colby (Transactions of the Society of Naval Architects and Marine Engineers, Part I, Vol. 46, 1938, p. 109; Part H, VoL 49, 1941, p. 208). . -Ventilation of Ships, by J. Dawson (Journal of The Institution of Heating and 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.8.N.R., and W. C.. 1 _____t h. O Uir V1 in KU9 -- 9K\ 1 ,: ,. ' , by Comdr. T. H. Urdahl, UJS.N.R. and Lt. John Everetts, Jr.. U.S.M.K. (Healing, 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- Bey (Heating, Piping ond Air Conditioning, August, 1943, p. 419). . Ventilation and Hating of Maritime Commission Ships, by J. W. Markert (Heating and Ventilating. Feb r. ua. r_y_, <1i9M4>3i, p-- . 32). nWnh..y. Q8hui:p_ iVrentilation, 1by Jt. iWs. Markert /(Hcjeait.i`ng a__n__dr Vtrentil1a_t.i-ng-, Oac.ito-bler, 19n4,3\). Ett.vo lution of Ships Ventilation Systems, by J. W. Markert (The Log, 1944 Yearbook, p. 202). Refrigeration, Air Conditioning, Ventilation and Heating, by H. E. Parker (Marine Engineering, Vol. II, The Society of Naval Architects and Marine Engineers,` 1944, Chapter VI, p. 319). Blackout at Sea, by J. W. Markert (Heating and Ventilating, March, 1944; p. 55). Your Merchant Marine Will be Comfort Air Conditioned, by J. W. Markert (Heating and Ventilating, May, 1945, p. 60). - ' Modern Air Conditioning, by J. W. Markert (Marine Engineering and Shipping Review, November, 1945, p, 177). ` Modern Marine Refrigeration andAir Conditioning, by W. H. Carrier and L. E. Starr (Morins Engineering and Shipping Review, April, 1946, p. 132). . -. Protects U. S. Navy's Inactive Fleet, by Capi. T. H. Urdahl and Comdr. E. R. Queer, (Heating, Piping and Air Conditioning, March, 1946, p. 71). - * ! Reconversion of Liner S. S. Lurline, by Robert Tate (Society of Naval Architects and Marine Engineers, May 12, 1949). Air Conditioning of P-2 American President Liners, by J. W. Markert (Pacific Marine Review, August, 1946). - Export Lines Air Conditioning of Four Aces, by J. W. Markert (Marine Engineering, March, 1949). CHAPTER 48 WATER SERVICES Sizing Cold Water Supply Piping, Procedure for Sizing Cold Water Systems, Cool ing Water Piping, Estimating Heating Load' and Storage Capacity, Methods . " 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 . ,1 .. 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. Intact, 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 satisfactory supply of water for a given fixture, and (2) the number of fixtures which may be assumed to be in use at.the same time. , .. The minimum flow that will be satisfactory to the 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 of dwelling also has considerable influence on the water consumption. In apartment houses the per capita daily water consumption is generally higher 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 sidered a safe design figure. . .v Although a considerable number of bousing projeks 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 consumption in housing projects falls in between the consumption in apart ment houses and that in single dwellings at the s$me geographical location. ' * - : ... ' .; ioi3 . ' 1014 CHAPTER 48 19S2 Guide Table 1. Proper Flow and Pressure Required During Flow for Different Fixtures Fixtubb -,,Flow Pbbbsubs* Flow gpm Ordinary basin faucet.................................................................... Self-closing basin faucet.................................................... Sink-faucet--| in..................... ................. ............... Sink faucet--jin..-......... ................................................... ' Bathtub faucet............ ..................... Laundry tub cock--l in..................................................................... Shower........................................................ ... Ball-cock for closet............................................................... Flush valve for closet................... ............................... Flush valve for urinal........................................................................ Garden hose, 50 ft, and sill cock...................................................... 8 12 10 5 5 \9. 15' 10-20 15 30 3.0 2.5 4.5 4.5 0 . rn fi n 30 15-4 01- 15.0 5.0 ? Flow,pressure is the pressure in the pipe at the entrance to the particular fixture considered. . Wide range due to variation in design and type of flush-valve closets. ` ' In general, a daily per capita water consumption of 40 gal can be iisedas 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 os Group* 'Water rlosrt . PfldMtfll urinal Stall or wall urinal Lavatory... Bathtub ' Kitchen , Water closet ... lavatory . Occupancy Type op Supply Control Weight in Fixture . Units? . ^ /. Water Services 1015 . No. 1 for system predominantly for flush valves. ` No. 2 for system predominantly for flush tanks. "' .. -. Fio. 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 umts. 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 umts 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 possible the determination of the design rate of flow in any particular section of piping. The next gen eral 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 pne of ascertaining the minimum pressure in the street .main, and the minimum Combination fixture Private__________ ,, Fauret 3 * For supply outlets likely to impose continuous demands, estimate continuous supply separately and 'add. to total demand for fixtures. - : 1 b For fixtures not listedt weights may be assumed by comparing the fixture to a listed one nng water in similar quantities and at wimiW rates. 0 The given weights are for total demand. For fixtures with both hot and cold water supplies, the weights for maximum separate demands may be taken as H the listed demand for the supply. V' Fig. 2. Section of Fig. 1 on Enlarged Scale 1016 CHAPTER 48 1952 Guide FRICTION LOSS IN HEAD IN LBS. PER SQ. IN PER IOO FT. LENCTH Water Services FRICTION LOSS IN HEAD IN LBS. PER SQ. IN. PER IOO FT. LENCTH 1017 . Fig. 3. Flow Chart for 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 maniifacturers' 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'tover- coining the difference in elevation between the water main and the highest fixture. . 'i Hie: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 . copper, brass, or lead may usually be classified as smooth. ' 15 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 being laid, are classified as rough. ' fI Figs. 3, 4 and 5 give the pipe friction losses corresponding to these three types of pipes for various nominal diameters.1 - Example 1: A 2J in. fairly rough pipe supplies 100 gpm of water. Find the fric tion loss in head if the pipe length is 200 ft. 1018 CHAPTER 48 1952 Guide FRICTION LOSS IN HEAD IN LBS. PER SQ. IN. PER 100 FT. LENCTH Water Services. 1019 Fig. 5. Flow Chart tor Rough Pipe Soliilion: 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 informal tiori oh 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, in pounds per square, inch for any given rate of flow. Experience has shown, however, that, the simplest method of expressing losses in fittings and valves is to use the, concept of an equivalent length of straight pipe. Thus it;has 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. . A. | in. laundry bibb (old style). ` E. Combination compression sink faucet B. Laundry compression faucet. F. Basin faucet. C-l. | in. compression sink faucet (Mfr. 1). G. Spring self-closing faucet. ' C-2. | in. compression sink faucet (Mfr. 2). H. Slow bcIf-closing faucet. I). Combination compression bath tub faucets (both open). . . . " - (Dashed lines indicate recommended extrapolation) 1020 CHAPTER 48 1952 Guide Table 3. Performance Requirements of Water Meters* * American Water Works Association Standards: _ >' _ - Registration. The registration on the meter shall indicate the quantity recorded to be notiess than 98 percent nor more than 102 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 shall be not less than 90 percent of the actual flow recorded when a test is made at the rate of flow set forth under minimum-test flow. 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 desirable1 to connect hose bibbs ahead of the reducing valve. .1 The principles involved in sizing either up-feed or down-feed systems are1 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 Dxametbr op Fitting In. Equivalent Length of Pipe foe Various Fittings 90 Deg Standard Ell Ft 45 Deg Standard Ell Ft 90 Deg Side Tee Ft Coupling or Straight Run of Tee Ft Gate , Valve -Ft Globe Valve Ft kz. i 0.6 1.5 0.3 0.2 8 2 1.2 3 0.6 0.4 15 H 2.5 1.5 4 0.8 0.5 20 3 1.8 5 0.9 0.6 25 \M.----------------------- 4 2.4 6 1.2 0.8 35 l H--- 5 3 7 1.5 1.0 45 2. _ 7 4 10 2 1.3 55 2>_ 8 5 12 2.5 1:6 65 3 10 6 15 3 2 80 3M---------------------- 12 7 18 3.6 2.4 100 4. 14 8 21 4.0 2.7 125 5 17 10 25 5 3.3 140 6_ 20 12 30 6 4 165 Angle Valve Ft 4 8 12 15 18 22 28 34 40 50 55 70 80 Water Services 1021 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. .. ; p = [P -- 0.43# - 10] TM where . p = average pressure loss per 100 ft of equivalent length of pipe, psi. P = pressure in street main, psig. r . (1) 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, J in. pipe.. . 30-gal Horizontal hot-water tank, j in. pipe Water meters (No valves included) ' , | in. with in. connections........................ . 4 in. with J in. connections......... ............ " | in. with | in. connections.......................... I in. with 1 in. connections.......................... II in, with-1 in. connections........ -... ( Water softener................ ...............................;.. Nominal Diameter of Pipe--Inches '1 " 4' 1.2 6.7 .4.8 3.4 --` . --- -- 1 17 '5 28 20 14 9 4.4 50-200 1 li . 56 ' ' '__ ' 16 ' ' -- 90 - __ 64 -- 45 ' '--- 30 115 14 . 54 ; -- . .--f , H = height of highest fixture above street main, feet. ` L = equivalent length determined in paragraph 4, feet. ' If the system is of the down-feed supply from a gravity tank, the height of water in the tank, converted to pounds per square inch by multiplying by 0.43, replaces .the street main pressure, and the term 0.43 H in Equation 1 is added instead bf 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 ithe value of p, calculated as in paragraph 6, choose the sizes of pipe from Figs. 3, 4 or 5. Examples: 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. Solution: From Fig. 2 the estimated peak demand is found to be 51 gpm. From Table 3 it is evident that several sizes of meters would adequately measure this flow. For a trial computation choose the 14 in. meter. From Fig. 6 the pressure drop through a 14 in. disc-type meter for a flow of 51 gpm is found to be 6.5 psi. Then the pressure drop available for overcoming friction in pipes and fittings is 55 - (15 + 50 X 0.43 + 6.5) => 12 psi. , At this point it is necessary to make some estimate of the equivalent pipe length of the fittings on the direct line from the street main to the highest fixture. The exact equivalent length of the various fittings cannot now be determined since the ipe sizes of the building main, riser, and branch leading to the highest fixture are not nown as yet, but a first approximation is necessary in order to make a tentative selection of pipe sizes. If the computed pipe sizes differ from those used in deter mining the equivalent length of pipe fittings, a recalculation will be necessary, using 1022 CHAPTER 48 1952 Guide. -Table 6. Computation op Branch Size in Example 2 ' Fixtures No. and Kind Fixture Units (From Table 2 and Note c) - Demand (From Fiol 2) Gpm Pipe Site ` (From Fig. 4) In. 3 x 6 = 18 } (2 x 2) = 3 i (3 x 1) = 2.25 23.25 38; the computed pipe sizes for the fittings. For the purposes of this example assume that the total equivalent length of the pipe fittings U 50 ft. _ ' Then the permissible pressure loss 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 riserSi 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 1H in. Items entering the computation of pipe size are given in Table 6. ' COOLING WATER PIPING . Water i3 veiy 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 op Reprig. Cooling Water GPM Pipe Sizes (Nominal 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 if 2 2i 2i 3 3 M. 2 3 4 4' ' 4 ' 75 100 150 200 250 225 300 450 600 750 5 6 56 5 8. 68 8 '8 Water Services 1023 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 codling sys tems, a pressure drop of the order of 2 to 3 psi per ItiO ft of pipe lengjth, 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 for Hot Water in Gallons Apartments and Private Homes No. or Rooms Numbeb or Bathrooms . 1 .2 3 4 1 2' '60 70 ' ' - . 3 80 -- __ __ 4. 90 . 120 . __ _. _5 . - -. 100 140 --- . __ , 6- 120 160 200 . 7 140 . 180 . 220 __ 8 160 200 240 250 9 180 220 1 260 275 10 11 . . 200 . . 240 . 260 280 300 300 340 12 -- . 280 325 380 13 -- 300 350 420 14 -- -- 375 460 15 -- -- 400 500 16 -- -- ' --* 540 17 -- -- - -- 580 _18 -- -- -- 620 19 -- --- -- 20 -- -- -- '-- 5 - ____ ___ __ __ __ __ 450 500 550 600 650 - 700 750 800 850 Hotels Room with basin.......... .................................. ............................................................................1' 10 Room with b&th---transient......................................................................................;.............. 60 Room with bath--resident......................................................................................................... 60 2 Rooms with bath..................................................................................................................... 80 3 Rooms with bath...................................................................................................................... 100 Public shower.................................................................................................................................. 200 Public basins.................................................................................................................................... 150 Slop sink___ '............. .................................................I.................................... .................... 30 Office Buildings White color worker (per person) Other workers (per person)........ Cleaning per 10,000 sq ft___ '.... Hospitals- IPer bed 2.0 4.0 30.0 80-100 tore 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. For 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 1024 CHAPTER 48 1952 Guide -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. Tn 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 of Buildings Type op. Building Hot Water Required Max. Hourly Duration Demand in op Peak Relation to Load Day's Use Hours Storage Capacity in Relation to Day's Use Heating Capacity in Relation to Day's Use Residences, apartments, 40 gal per hotels, etc. peison per day* Office buildings 2 gal per person per day* . Factory buildings 5 gal per person per day* Restaurants 1/7 1/5 1/3 4 1/5 = 1/7 2 1/5 1/6 1 2/5 . - 1/10 1 1/8 1/10 Restaurants 3 meals per day Restaurants 1 meal per day 1/10 8 1/5 . 1/10 1/5 2 2/5 1/6 * At 140 F 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 water 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 S: 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 re- Water Services 1025 quirement of 6 X 40 = 200 gal. per day, and a maximum hourly demand.of.200 X 1/7- = 28.5 gal. The heater should have a storage capacity of 200 X 1/5 = 40 gal, and a; heating capacity of 200 X 1/7 = 28.5 gal per hr. i The conditions given in Example S may be cited as average. It is pos sible 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 lOOO.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 nr. Water required for 4-hr peak =4 X 1140 = 4560. .| . . . If a .1000 gal storage tank is used, hot water, available from the tank = 1000 X 0.75 = 750. Water to be heated in 4 hr = 4560 -- 750 = 3710 gal! Heating capacity per hour 3710/4 = 930 gal. ,, If instead of a 1000 gal tank, a 2500 gal tank had been installed, the required heat i-ng capacity per rh. our wou,ld, ,be 4-5--6-0-------- (--250--0 --X --0.7=5) 671 gal. , Table 10 may be used to determine the size of water heating equipment from the number of fixtures. To obtain the probable maximum demand, multiply the total quantity for the fixtures by the demand factor in line 11. The heater or coil should have a water heating capacity equal to 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 6 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 gal per hr 1 30 bathtubs....................................................................... X 20 = 600 gal per hr 30 showers.......................................................................... X 75 = 2250 gal per hr 60 kitchen sinks................................................................ X.10 = 600 gal per hr 15 laundry tubs................................................................ X 20 = 300 gal per hr Possible maximum demand....................................'... = 3870 gal per hr Probable maximum demand....................... = 3870 X 0.30 = 1161 gal per hr Heater or coil capacity................................................... = 1161 gal 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. The amount of 180 F water needed in restaurants per day may be determined according to the method outlined by the American Gas Association* in the following paragraphs: . 1. Multiply the number of meals per day by the number of dishes per meal (6 for low-price restaurants, 8 for medium-price restaurants, and 10 for high-price 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 number of meal periods per day (one, two or three) by the dish- 1026 CHAPTER 48 1952 Guide washing tank capacity in gallons, giving the gallons of 180 Fwater per day necessary to fill the tanks. . 5. Add values from paragraphs 3 and 4 to obtain the total number of gallons of 180 F water required per day. . . . For purposes other than dishwashing, a considerable amount of 140 F water is also used. To find the daily 140 F water requirement in a 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.' 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 Water'Demand peb Fixtubes fob Various Types of Buildings Gallons of water -per hour per fixture, calculated at a final temperature of 140'F Apart ment House Club ,, Gym nasium Hos pital Indus Hotel trial Plant Office Build ing Pri vate Resi dence School Y.M. C.A. 1. Basins, private lavatory 2 2 2 2 . 2 2 6 62. Basins, public lavatory 4 8 8 12 2 6. 3. Bathtubs........................... 20 20 30 20 20 30 4. Dishwashers.................... 15 50-150 50-150 50-200 20-100 5. Foot basins....................... 6. 'Kitchen sink___;........... 3 10 3 ' 12 20 33 20 .20 12 20 7. Laundry, stationary 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 15 11. Demand factor............... 0.30 0.30 0.40 0.25 0.25 | 0.40 | 0.30 12. Storage capacity factor* 1.25 | 0.90 1.00 0.60 0.80 | 1.00 | 2.00 2 20 15 3 10 20 5 75 15 0.30 0.70 22 15 8 30 20-100 20-100 3 12 10 *20 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 first 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 1027 section or fire-brick lining 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 life. 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-buming heaters. As they have the same tendency as coalboilers 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 Heateb 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 16. Electric water heaters for domestic hot water supply are described in the section Heating Domestic Water by Electricity in Chapter 41. In the indirect method, either steam or hot water is used for heating the water. With steam, the water to be heated is preferably circulated around the outside of the steam tubes which are submerged within a tank. A typical indirect heater using steam is shown in Fig. 8. The coils usually are 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 lining, 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 1028 CHAPTER 48 1952 Guide' Fig. 9. Indibect Wateb Heater Mounted on Side of Boileb. 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 tubeboilers and small residential boilers. In this casethe heat transfer surface, is in the form of a number of straight copper tubes, with rear U-bends or afloating 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,' Hot water ' to fixtures Fig. 10. Indibect Wateb Heateb Placed in Boileb -Water Services 1029 and by fittings and restrictions, so that the water attains the desired temperature in one passage through the coil. This arrangement is fre-r 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. 42. , ' COMPUTING HEAT TRANSFER SURFACE ,: The area of the inside surface of a heating coil may be determined from Equation 2. Q X 8A3(<t - ti) A U X tm . (2) where A = surface area of coil, square feet. <2 =. quantity of water heated, gallons per hour. .. 1, = hot water outlet temperature, Fahrenheit. .; . . I, = 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 17 = 240 (steam) and 100 (hot water). . For iron coils [7 = 160 (steam) and 67 (hot. water). . . . ta -- logarithmic mean of the difference between the. temperature of the heating ; medium and the average water-temperature, and is approximately: '-[/kTe] i, = 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 manufacturers published ratings.' . ' Example 6: What area of copper transfer surface will be required to heat 70 gal of water per. hour from 40 to 180 F with boiler water at 220 F? Solution: . , t, (180 + 40)1 2 . -1 no 70 X 8.33(180 - 40) 100 X 110 7.42 sq ft ' For instantaneous submerged heaters, the surface required will depend upon (1) the velocity of water in the tubes, (2) the'boiler water tempera ture, (3) the inlet water temperature, (4) the outlet water temperature, (5) the cleanliness of the coil surface, and (6) the condition of the boiler water surrounding the coil. If the heater is located in the water of an ac- 1030 CHAPTER 48 1952 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 y/v may safely be used. (t> = 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, Tui.ii 11. Coefficient of Heat Transfer of Instantaneous Water Heaters U = Blu per (hr) (sq 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, fixture^. In average-sized and small residences and systems, in 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 down- feed 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 circulationisemployed. InFig. 11 (a) and (b), this is accom- Water Services 1031 plished 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, or a fixture branch is connected to the top of the main where air venting is desired, and then dropped to the fixture outlet. It is sometimes necessary to make an allowance for 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 ag 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. 11 1- ri i'! "-I -\ Q. Ij 3 `^ W a. Ss 'a. ' a. C3 33 3 S to y `W <o 1 1_ _ i 1 1 JJ J J/ ^ -- o .O <c> Fig. 11. Methods of Arranging Hot Water Circulation Lines 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 (in the return line) set to start and stop the pump over approximately a 20 F deg temperature range. - CONTROL OF SERVICE WATER TEMPERATURE Coal-fired boilers are usually controlled by ah immersion thermostat (located in the heated water) which opens or closes draft dampers at the boiler to adjust the rate of fuel combustion. With oil or gas-fired boilers, the immersion thermostat controls the oil burner or the automatic gas valve. The gas pilot flame usually burns continuously. With electric heaters, the immersion thermostat operates a switch on the source of energy. When steam or hot water is the medium for heating the water in the tank, an immersion thermostat is used to control a valve in the steam or hot water supply line. In small residence installations, using water as the carrier, a combined immersion thermostat and butterfly valve in one simple 1032 CHAPTER 48 1952 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 miming, it is-usual to insert a weighted check-valve in the house heating main so that no circulation to the house heating system can occur unless the pump operates. In summer the fire may be controlled to maintain a boiler water temperature lower than when heating, and generally about 20 F warmer than that desired in the domestic hot water system. . The immersion thermostat in a hot water storage tank should be located no higher than the center of the tank, and possibly should be even closer to the bottom, since water in a tank stratifies proportionally to the 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 piressure-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 of discharge should be such as to limit the pressure rise for any given heat input to 10 percent of the pressure at which the valve is set to open. For any given installation, the discharging capacity should be in excess of the water to be discharged by the heater. The heater discharge Qm in gallons per minute may be computed by Equation 3: ........... ' ' - Water Services 1033 i Q,,-= 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. .. Tank Connections Coil Inclination The capacity of temperature relief devices' may be calculated by Equa tion 4: . 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 been 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 essentially of a storage tank, heating coil, and hot box. The coil is installed in the hot box, and is arranged to circulate water to and from the storage tank. The advantage in. the use of this type of heater is the fact that it ' 1034 C/ H* APTER 48 1952 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. Hue 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: ,, Qo X 0.50 s= 0.75 = 0.666Qd (5) where S = storage capacity of tank, gallons. Qd = 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 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 bn 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. Water Services 1035 Table 12. Suggested Solar Heater Design Data* Design Item Based on Rate of 30 Gad peb Day pbb Person Based on Rate op 40 Gad peb Day pbb Person No. of Occupants in Residence.. 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8 Hot Water Used at Night, gal per person...........................: 15 ' 15 15 15 15 15 15 15 20 20 20 20 20 20 20 20 Hot Water Used at Night, gal total................................................. 15 30 45 60 75 90 105 120 20 40 60 80 100 120 140 160 Retained in Tank, 25 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 94 113 130 150 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 Total Water to be Heated: Gal per 8 hr period....................... 35 70 104 135 169 203 235 270 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, so ft......................... 25 50 75 100 121 145 168 192 32 64 96 128 160 192 224 256 Equivalent length 1 in. ooil, ft. 100 200 300 400 484 580 664 768 128 256 384 512 640 768 896 1024 Box Size: ' flArea, so ft......................................... 25 50 75 too 121 145 168 192 32 64 96 128 160 192 224 256 Width, ft....................... .................... 6 78 10 10 11 4 6 8 9 in 11 12 12 Length, ft.......................................... 6 8 11 12.5 13.5 14.5 16.5 17.5 8 10 12 14 16 18 19| 21 * Sun Effect and the Design of Solar Heaters, by H. L. Alt (A.S.H.VJ3. Transactions, Vol. 41, 1035, 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 1036 CHAPTER 48 /- 1952 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 needmg 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.* ' . 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) 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 49 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'*- * * The present purpose is to discuss the use and characteristics of the more im portant instruments.. .' TEMPERATURE MEASUREMENT*' 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-filled 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 minus 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 is often accomplished with the instrument completely immersed in a bath at . the 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 by means of the following formula: where K = 0.00009 D (1, - U) K = correction to be added, Fahrenheit degree's. 1037 (1) 1038 C/ H'APTER 49 1952 Guide ' D = Dumber of degrees on the thermometer scale which are not immersed, fi = temperature indicated on the thermometer, Fahrenheit degrees, ti = temperature of the non-immersed mercury column, Fahrenheit degrees. . 0.00009 = difference in the coefficient of expansion of the mercury and glass. - tA 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 i3 placed at a point at which it is desired to observe the temperature. In practice it i3 desirable to utilize Amf 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 observa tions 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 B is adjusted so that the galvanometer shows zero current. Battery 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, copperconstantan are satisfactory and develop a relatively large emf of 40 to 60 Instruments and Measurements 1039 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. 1) 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 ther mocouples 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 average temperature. Thermocouples in parallel, haying the similar metals of . a number of couples connected together and run to a common cold junction, will, cause an indication on a potentiometer which is the true emf only if the electrical resistances of the parallel junctions; are the same.9-10 1040 CHAPTER 49 1952 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 operaation; 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. flovf through coil L than through coil H. This causes an in crease in' the force exerted by coilL, 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 Bt. 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 measurements; but, generally, because of its construction it is more costly and is apt to have considerable lag. It gives best results when used to measure steady or slowly changing temperature. For accurate results the entire thermometer coil must be exposed to the' temperature to be measured. . 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 1041 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. . r 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 Gages PRESSURE MEASUREMENT . . 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 are as follows: 1 Standard Atmosphere = 14.696 lb per sq in. =* 29.921 in. mercury at 32 F = 33.96 ft water column at 68 F For most ordinary purposes, the following figures are of ample accuracy: I 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 important, except insofar as it affects the meniscus through wetting or surface tension. Bores of at least A in. for rough, and | in. for more precise, measurements 1042 CHAPTER 49 1952 Guide 'are recommended. Liquids other than water are sometimes used for low pressure measurement and, when this is done, the readings must be cor rected 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.11 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.11 For measuring low pressure differences to within 0.001 in. of wafer, verysensitive 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.1*. 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. 3This 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 parr 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. hit - 28.630) (1.11231 -10978) (2) where C = correction to be subtracted, inches of mercury. Instruments and Measurements. ' 1043 . 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 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 are called upon to measure the flow of air more often than that of other gases, and usually the air is measured at or near atmospheric pressure. Under this condition, the air can be treated substantially as an incompressible fluid which implies that simplified formulas can be used with sufficient accuracy for the solution of many problems.18 The Pitot Tube ` The construction of the Standard Pitot Tube11 is shown in Fig. 3. Thie formula for velocity used in conjunction with it, is as follows: 7,, = 1096.5 (3) 1044 CHAPTER 49 1952 Guide where ' Vm = velocity, feet per minute. _ hn = 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 com puted. Suggested Pitot tube locations for traversing round and rectangu lar 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. In rectangular ducts the readings should be taken in the center of equal areas over the cross-section of the duct. The number of spaces should not be less than 16, and need not be more than 64. When less than 64 are taken, the number of equal spaces should be such that the centers of the areas are not more than 6 in. apart. In determining the average velocity in the duct from the read ings given, the calculated individual velocities or the Square roots of the velocity heads must be averaged. It is incorrect to use the average velocity head for this purpose. Pulsating or disturbed flow will give erroneous results and therefore, if possible, the Pitot tube should be located at least 7\ 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 1$ diameters ahead of the Pitot tube.1* 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 pur poses 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 1045 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 extraor dinary 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. Ob = 5.2KYD* A. (4) where Qm = air flow, cubic feet per minute. K = orifice coefficient. Y = expansion factor, see Fig. 5. D -- orifice diameter, inches. d -- pipe diameter, inches. Ti = temperature of air at orifice, Fahrenheit degrees, absolute. Bi = absolute pressure ahead of orifice, inches of mercury. = absolute pressure after orifice, inches of mercury. hw = pressure drop through orifice, inches of mercury. . As most laboratories are less than 1000 ft above sea level, precision is ade quate in many cases if standard atmospheric pressure, 29.92 in. Hg, is assumed. Equation 4 then becomes. Qm = 0.95kYD* \/?U. (5) 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 RT, P = pressure, pounds per square inch, absolute. R = 53.3, the gas constant for air. Tt = temperature of the flowing air, Fahrenheit degrees, absolute. (6) " The thin-plate square-edged orifice often has a discharge coefficient K 1046 CHAPTER 49 1952 Guide near 0.60. The exact value dependson the location of the connections, the pressure drop, the diameter ratio of orifice to pipe, and the sharpness of the edge."'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 isiess. 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 VentiIator-Codes,1 and in A.S.R.E. Circular 13*. 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 Wile14 in an article in which pertinent informa tion on nozzle discharge coefficients, Reynolds numbers, and the resistance Fig. 5. Expansion Factob fob Aib and Other Diatomic Gases Applicable to Flange, Radios 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 1047 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,18 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 pressures. Each instrument, and the attachments for it, must receive individual cali bration. For determining average velocity in a duct, it is necessary 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 accu racy, 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.18'17 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 0.85.11 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 minimum velocity. This is the main reason for the large difference in ratings of unit ventilators by the anemometer method, and by air volume measurements in a duct approach to the inlet.19 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 jet on the end of a rubber tube has been found especially convenient and accurate on supply grilles.10 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 1048 CHAPTER 49 1952 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, partic ularly 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." 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." 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 hol-vrire anemometer, a very fine heated wire is employed as a resistancethermometer element whose temperature may be determined accu rately." '* 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.*6 The heated-thermocouple anemometer is cali brated to give velocity in terms of the differential emf between heated and Instruments and Measurements 1049 unheated thermo-jjunctions exposed to an air stream."-w 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 temperature, humidity and pressure upon the air properties which influence convective heat transfer.*7 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 In the past, efforts have been made to determine the rate of air change in buildings by impregnating the air with C02, hydrogen, water vapor or another substance, and then observing the rate of decrease in concentra tion*8 with an Orsat apparatus, a psychrometer or another suitable means. Success has not been attained in a satisfactory degree, chiefly because build ing materials absorb or reject the substances used to impregnate the air, thus impairing the precision of the tests. Recent experiments iri England are described in a paper by Dick.*9 . HUMIDITY MEASUREMENT Psychrometers . ....... "' ... Any instrument capable of measuring the humidity or hygrometric state of the air is a hygrometer. A psychrometer is aparticular kindbf hygrom eter which consists of two mercury thermometers, one of which-Kas 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.40 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 continued until the thermometer readings, become steady. Due to evaporation,, the wet-bulb thermometer will indicate a lower temperature than the dry-bulb thermometer, and the difference is known as the wet-bulb depression. Charts and tables are available showing the relation between;lhe thermom eter readings and the humidity.41,41; Data are usually based bn a total pressure of-one standard atmosphere. For precise work, a correction.-is necessary for barometric pressure and is usually made by multiplying the observed relative humidity by the ratio of the observed to the standard atmospheric pressure. .... For air temperatures below 32 F, the water. on the wick may either freeze or 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. - 1050 CHAPTER 49 1952 Guide -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 are used 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 thermometers in fluids in contact with the back of the mirror, but in modern instruments thermocouples are used, and are soldered or welded to the mirror itself. The dew-point apparatus is not so commonly used as the psychrometer, probably because it is less convenient. It is usable, however, for higher temperatures than the wet-and dry-bulb psychrometer, and should be con sidered for dew-points near or above the boiling point, as in the case of'flue gases. Special apparatus for high.precision has been constructed, in which the photronic cell and a light source are used for dew or frost detection instead of visual inspection. 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 instrument 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 hu midity, some operators report satisfactory reproducibility of results. 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 Instruments and Measurements 1051 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 testgas, and to a standard gas having a known absolute humidity. The pressure of the standard gas is varied until contact with it establishes the same resistance in the film as the test gas, and the humidity of the test gas is then determined by computation based 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.V.E. in 1942, and has become practically universal, and the apparatus is de scribed in an A.S.T.M. publication.45'48 It consists essentially of an elec trically 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 of each specimen by a clamp screw. Hot plate apparatus accommodating specimens on the order of one foot square and an inch or more thick, is common. The apparatus at the National Bureau of Standards takes speci mens 8 in. square, while plate3 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, 1052 CHAPTER 49 1952 Guide -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 A.S.H.V.E. Standard Test Code for Heat Transmission through Walls.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 meas ured, converted to Btu per hour, and divided by the area and the tempera ture difference through the wall, from surface to surface, to yield the conductance of the wall. The transmittance or 17-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 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.51 A heat balance consists in the simultaneous application of both tests to the same device. The indirect test almost invariably indicates the greater capacity, Instruments and Measurements 1053 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 ah arbitrary radiation and unaccounted for factor.51 .. 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 extracted by potassium hydroxide. The sample is then remeasured and successively passed into the second and third pipettes, where the oxygen and the carbon monoxide are respectively extracted by potassium pyrogallate and cuprous chloride. . For field testing and burner adjustment, simpler portable devices are available for carbon dioxide determination only. From curves, based on typical hydrogen content of several common fuels, efficiencies may be Table I. Ringelmann Smoke Chart Spacings Nuwbeb or Card i 2 3 4. Thickness op Lines, mm 1.0 2.3 3;7 5.5 ' Distance in Clear Between lines, mm 9.0 7.7 6.3 4.5 . . 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 - 54 In large plants, carbon dioxide recorders are used to obtain a continuous indication of the plant's efficiency.55 SMOKE DENSITY MEASUREMENTS - : Ringelmann chartf are widely used for evaluating the density of smoke discharged from chimneys or stacks, and smoke ordinances are based on them in some cities. Each chart is composed of a series of crossed black lines on white paper which, at a distance of about 50 ft, is visually compared with the smoke under observation. Four charts are used with different degrees of blackness as shown in Table 1. The smoke density is specified by Ringelmann numbers from 1 to 4. The photoelectric cell' is used in -some apparatus developed for smoke density recording in large plants. The same device is included in the test ing equipment for domestic oil burners described in National Bureau of Standards, Commercial Standard CS75-42.50 Under Laboratory Tests this publication contains the following section: "Smoke Determination.--After combustion has reached equilibrium, the amount of smoke in the flue gases, when viewed lengthwise through 4 feet of the smoke pipe in accordance with the Underwriters' Laboratories, Inc., Standard for Domestic Oil Burners (Subject 296), March 1934 and subsequent revisions, shall not reduce-the output of a standard photoelectric cell from 9 microamperes, with a clear 1054 CHAPTER 49 1952 Guide 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 SmithGreenburg 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 during 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 Cleaning 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 rates is then indicative of the effectiveness of the cleaner in arresting dust. A statement of an air cleaner's efficiency by any test method, is meaningless unless the test dust is specified. Other instruments for determining gaseous and particulate air con taminants are described in industrial hygiene literature.67 61 68 68 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 Instruments and Measurements 1055 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 1 Standard Code for Testing and Rating Steam Unit Beaters, adopted January, 1030, by A.S.H.V.E., revised 1950. - * A.S.H.V.E. Standard Code for Testing and Rating Steam Unit Ventilators (A.S.H.VJ5. Transactions, Vol. 38. 1932, p. 25), adopted June, 1932. > * A.S.R.E. Standard Methods of Rating and Testing Air Conditioning Equipment, A;S.R.E. Circular No. 13. * , * 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). .. 1 Temperature Measurement (A.S.M.E. Power Test Code, Part 3). - * Investigation of Warm Air Furnaces and Heating Systems, by A. C. Willard, A. P. Brats V. S* Day (Illinois 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). . M American Standard for Indicating Pressure and Vacuum Gages, Round Dial Type, with sure Chamber, B. 40.1 1939- American Standards Association). Pres Standard Test Code for Centrifugal and Axial Fans, 1938 {A.S.H.V.E. and N.A.F.M.) published by N.A.F.M. as Bulletin No. 110. . . - u Fan Engineering, Buffalo Forge Company, 5th Edition, p. 165. ` ' u Illinois Micromanometer (University of Illinois, Engineering Experiment Station Bulletin No. 120, p. 91). 11 The Weathertightness of Rolled Steel Windows, by J. E. Emswiler and W. C. Randall (A.S.H.V.E. Transactions, Vol. 34, 1928, p. 527)- * Pressure Measurement (A.S.MJS. Power Test Code 1936, Part 2, Chapter 2). n The Measurement of Static Pressure, by C. J. Fechheimer {Mechanical Engineering, August, 1927). 11 Psychometric Tables for Vapor Pressure, Relative Humidity and Temperatures of the Dew-Point (U. S. Department of Agriculture, Weather Bureau, Washington, D. C.). 11 For technical data refer to Fluid Meter Reports, Parts 1--1937, 2--1931, and 3--1933 (American Society of Mechanical Engineers). . * Technical Notes No. 546 (National Advisory Committee for Aeronautics, November, 1935). ** The Characteristics of Double Pitot Tubes, by F. R. Ingram, E. Diez-Cahseco and L. Silverman (A.S.H.VJ3. Journal Section, Heating, Piping and Air Conditioning, November, 1942, p. 708). ` ' _ a Discharge Coefficients of Square Edged Orifices for Measuring the Flow of Air, by H. 8. Bean, E. Buck ingham and P. S. Murphy (Bureau of Standards Journal of Research, Vol. 2, 1929, p. 561). ** Flow Measurement by Nozzles and Orifice Plates (A.S.M.E. Power Test Codes, Chapter 4 of'Part 6 1940). u Air Flow Measurement in the laboratory, by D. D. Wile (Refrigerating Engineering, June, 1947, p. 515). u 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.VJ5. Transactions, Vol. 48, 1942, p. 241). . a` A.S.H.V.E. Research Reports Noe. 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). ** 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.VJE. Transactions, Vol. 38, 1932, p. 463). * 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.VJ2. Transactions, Vol. 44, 1938, p. 77). n Measuring Air Flow, by G. L. Tuve (Heating, 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.V.E. Transactions, Vol. 45, 1939, p. 645). . . ?v- 1056 CHAPTER 49 1952 Guide 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). 44 A.8.H.V.E. Research Report No. 1165--Development of Instruments for the Study of Air Distri bution in Rooms, by A. P. Kratz, A. E. Hershey and R. B. Engdahl (A.S.H.V.E. Transactions, Vol. 46, 1940, p. 351). Development of Testing Apparatus for Thermostats, by D. D: Wile (A.S.-H.VJ2. Transactions, Vol. 42, 1936, p. 349). .. ' * 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.V.E. Journal Section, Heating, Piping and Air Conditioning, Vol. 22, September, 1950, p. 146). **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 Seo TION, Heating, Piping and Air Conditioning, May, 1950, p. 131). 44 The Temperature of Evaporation, by WilliB H. Carrier (A.S.H.VJ3. Transactions,-Vol. 24,1918, p. 25). ** Psvchrometric Tables for Vapor Pressure, Relative Humidity and Temperatures of the Dew-Point ( XJ. 8. Department of Agriculture, Weather Bureau, Washington, D. C.). 43 A Review of Existing Psychrometric Data in Relation to Practical Engineering Problems, by W. H. Carrier and C. O. Mackey (A.S.M.E. Transactions, January, 1937, p. 33; Discussion A.8.M.E. Transactions, August,. 1937, p. 528). . PHvided 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 Plate adopted July, 1942, by A.S.H.V.E. (A.S.T^S. Designation C177 - 42T). . 44 Guarded Hot Plate Apparatus Complying With the Requirements of Section 4 of AJ5.T.M. Method of Test for Thermal Conductivity of Materials by Means of the Guarded Hot Plate, A.S.T.M. 41 A.8.H.V.E. Standard Test Code for Heat Transmission Through Walls (A.8.H.VJ3. Transactions, VoL 34, 1928, p. 253), adopted 1928. ' 44 A.8.H.V.E. Research Report No. 685--Measuring Heat Transmission in Building Structures and a Heat Transmission Meter, by P. Nicholls (A.8.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. Krats and C.-E. A. Winslow (Year Book, American Journal Public Health, 36-37). 44 The Thermo-Integrator--A New Instrument for the Observation of Thermal Interchanges, by C.-E. A. Winslow and Leonard Greenburg (A.8.H.V.E. Transactions, Vol. 41, 1935, p. 149). IeB"R Testing and Rating Codes for Low Pressure Heating Boilers, 1947 (Institute of Boiler and Radiator Manufacturers). 44 Commercial Standard for Warm Air Furnaces Equipped with Vaporizing Pot-Type 00 Burners, C.S. 104-46 (National Bureau of Standards). - 44 Rapid Determination of Small Amounts of Carbon Monoxide, by Martin Shepherd (Ind. Eng. Chem. Anal. 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. S. Bureau of Mines, Technical Paper No. 355, 1926). 44 Commensal Standard for Mechanical Draft Oil Burners Designed for Domestic Installations, C.S. 75-42 (National Bureau of Standards). 43 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. Lewis (A.S.H.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.VJ2. Transactions, Vol. 39, 1933, p. 225), ' w A Test Method for Air Filters, by Richard 8. 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 (Interecience Publishers, Inc., New York, 1941). ' 44 The Determination and Control of Industrial Dust, by J. J. Bloomfield and J. M. Dalla Valle (17. S. PvMtc Health Bulletin No. 217, 1935). _ . a Sampling and Analysis of Atmospheric Contaminants, by F. A. Patty (Industrial Hygiene and Toxi cology, Vol. I, Interscience Publishers, Inc., New York, 1948). . 44 Electrical Engineer's Handbook, by Harold Pender and Knox Mcllvaine (John Wiley and Sons, New 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 Standarde Association). ' CHAPTER 50 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 by Vakious Societies and Associations ` Subject Title Sponsor Reference Acoustics American Standard Acoustical Ter (Terminology) minology (Proposed): Air Conditioning Code of Minimum Requirements for Comfort Air Conditioning (1938). AS of A ASHVE ASRB . ASA Z24.1 ASHVE Air Conditioning Code and Manual for the Design and .. NWAH A ACA . (120,000 BtuI. Installation of Warm Air Winter Air Hr or less) . Conditioning Systems (1945). NWAH A ACA t Manual No. 7 Air Conditioning The Technical Code for the Design (Above 120,000 and Installation of Mechanical Btu/hr) Warm Air Heating Systems (1948). NWAH A ACA . . NWAH A ACA Manual No. 9 , Air Conditioning Standards of the NBPU lor the Instal lation of Air Conditioning, Warm Air Heating, Air Cooling and Venti lating Systems. NFPA ' NBFU NBPU "Pamphlet-No. 90. Feb. 1950 Air Conditioning ASHE Standard Methods of Rating /Equipment) . and Testing Air Conditioning Equipment (1942). Air Conditioning ASRB Standard Methods of Rating (Equipment) and Testing Air Conditioners (1949).. (Supersedes ASRB Circular 13-42) ASRB ASHVE NEMA RMA ACMA ASRB ASRB . Circular No. 13-42 ASRB Standard 16-R Airplane Aeronautical Recommended Practice for Heating and Ventilating Air planes (1943). SAB SAB ARP 85 Airplane Aeronautical Recommended Practice for Internal Combustion Type Air plane Heaters (1945). SAB . SAB . ARP 143A Attic Ventilation Residence Ventilation Guide (1950). Boilers I=B=R Testing and Rating Code for Low Pressure Heating Boilers (1950). PFMA IBR PFMA IBR . Boilers Net Load Reoommendations for Heat ing Boilers. Publ. semi-annually. . HP A ACCNA HP A ACCNA Boilers Net Square Feet Radiation Loads in 70 Deg Fahr, Recommended for Low Pressure Heating Boilers (1948). - HP A ACCNA HP A ACCNA Boilers Boilers Standard and Short Form Heat Bal ance Codes for Testing Low Pressure Steam Heating Solid Fuel Boilers (Codes 1 and 2)(1929). ASHVE Performance Test Code for Steam Trying Solid Fuel Boilers (Code No. 3)(1929). ASHVE ASHVE ASHVE t ASHVE Boilers - - ASHVE Standard Code for Rating Steam Heating Solid Fuel Hand Fired Boilers (Revised April 1930). ,ASHVE ASHVE 1057 1058. - -. . CHAPTER 5 / Table 1. Codes and Standabds--(Continued) 1952 Guide - Subject Title Sponsob Reference Boilers. ASHVE Standard Code for Testing Steam Heating Boilers Burning Oil Fuel (1932). ' . ASHVE - ASHVE Boilers ASHVE Standard Code for Testing Stoker-Fired Steam-Heating Boilers (1938). Boilers - ' ASME Boiler Construction Code for Low Pressure Heating Boilers (1946 with 1948 Addenda). ' Boilers * , ASME Boiler Construction Code ' (Combined Edition) (1048 with 1947 Addenda). ' ASHVE ASHVE ' '-'ASME ' 'ASME ' ., ASME . . ASME Boilers (Gas) American Standard Approval Re quirements for Central Heating Gas Appliances (1951) A.Q.A. ASA Z21.13.-1951 Boilers (Miniature) ASMS Miniature Boiler Code (1946). ASME ASME Boilers (Power) Boilers (Power) ASME Power Boiler Code. Including Rules for Inspection (1946) with 1947 Addenda). Suggested Rules for Care of Power Boilers (1946). * ASME - ASME ASMS ASMS Boilers (Steel) Steel Boiler Institute Rating Code for Commercial Steel Boilers and Resi dential Steel Boilers (1948). Boilers (Steel)' Simplified Practice Recommendation for Steel Firebox Boilers and Steel. Heating Boilers (Commercial and Residential Types) (1950). Boilers (Steel) SBI Code for Testing Oil-Fired Resi dential Steel Heating Boilers (1948). SBI BS _ SBI SBI SBI BS ' R157-50 SBL 'Boilers (Steel) ' SBI tinting Code for Scotch Type Boilers (Over 15 pei 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 Requirements Buildings American Standard Building Re quirements (1946). - Basic Building Code (Also published in Abridged form as Abridged Building Code) 1950. NBA USPHS . BOCA : ` ASA A53.1-1946 BOP Burners (Anthracite) Burners (Gas) Commercial Standard for Domestic Burners for Pennsylvania Anthra cite (Underfeed Type) (1940). - American Standard Requirements for. Installation of Domestic Gas Con version Burners (1948). - BS -. AIL * A.G.A.. BS CS48-40 ASA Z21.S-1948 Burners (Gas) American Standard Requirements for - - - - A.Q.A. . Installation of Gas Burning Equip ment in Large Boilers (1950). ASA Z21.33-1950 Burners (Gas) American Standard Testing Require ments for Gas Conversion Burners (1948). A.G.A. ASA Z21.17-1948 Burners (Oil) Commercial Standard for Mechanical- Draft Oil Burners Designed for Do mestic Installations (1942). BS OBI BS CS75-42 Chimneys (Flue American Standard Sixes of Clay Flue Linings) Linings (1947). AlA PC ' ASA A62.4-1947 Cleaners (Air) ASHVE Standard Code for Testing and Rating Air Cleaning Devices Used in General Ventilation Work (1934). - ASHVE See ASHVE Transac tions, Vol. 39, 1933, p. 225 Codes and' Standards 1059 Table 1. Codes and Standadds--(Continued) Subject | Title Sponsob Reference . Coils , Proposed Commercial Standard for Rating and Testing Air Cooling Coils Using Non-Volatile Refriger ants (1945). BCMI BS BS TS 4044 Color Scheme (Piping) Color Scheme (Piping) Scheme for Identification of Piping Systems (1945). Scheme for Identification of Piping Systems (1928). HP A ACCNA : ASMS HP A ACCNA Engrg. Stds., Sec. 2 Part V .. ASA A13-1928 Compressors ' ASRB Standard Methods of Rating and Testing Refrigerant Com pressors. . ASRE * ASHVE ACRMA ASRB Standard 23 Condensers ASRB Standard Methods of Rating and Testing Evaporative Conden sers. ASRE ASHVE ACRMA ASRE Standard 20 Condensers ASRE Standard Methods of Rating, and Testing Water-Cooled Refrig erant Condensers. : ASRB ASHVE ACRMA... ASRB Standard 22 ' Condensing Units ASRB Standard Methods of Rating and Testing Meohanical Condensing Units (1940). ASRE ASHVE . .ACRMA . . ASRE Standard 14-41 Conductivity - Standard Method of Test for Thermal Conductivity of Materials by Means of the Guarded Hot Plate (Tenta tive) (1942). : ASHVE ASRE. ASTM NRC . ASHVE Control Equip ment (Indus trial) Underwriters* Laboratories, Inc., Standard for Industrial Control Equipment (July 1938, reprinted Sept. 1945). ' UL . : . UL Subject 508 Controls Underwriters* Laboratories, Inc., s Standard for Temperature Indicat ing and Regulating Equipment (Jan. . 1947). . UL UL Subject 873 . Convector ASHVE Standard Code for Testing and Rating Concealed Gravity Type Radiator (Hot Water Section) (1933). . ASHVE ASHVE Transactions, Vol. 39, 1933, p. 237 Convector ASHVE Standard Code for Testing - ing and Rating Concealed Gravity Type Radiation (Steam Code) (1931). , ASHVE ASHVE Transactions, Vol. . 37, 1931, p. 367 Convector Commercial Standard for Testing and . Rating Convectors (1947). BS . CMA IBR , BS CS 140-47 Coolers (Air) ASRB Standard Methods of Rating and Testing Forced Circulation and Natural Convection Air Coolers for Refrigeration (1945). . ASRE ASHVE ACRMA - REMA . ASRE Circular No. 25-44 Coolers ASRE Standard Methods of Rating and Testing Water and Brine Coolers- . '. . ASRB . ASHVE ACRMA ASRB . Standard 24 Ducts and Fittings . Simplified Practice Recommendation for Pipes, Ducts and Fittings for Warm Air Heating and Air Condi tioning (1945). Mfrs. . . BS . BS R207-49 , Exchangers (Heat) Standards of Tubular Exchanger Afanufaciurers Association (1941). 1 TEMA . TEMA ' . Exhaust Systems American Standard for Grinding, Pol ' ishing, and Buffing Equipment Sanitation (1941). AFA ASA Z43-1941 Exhaust Systems Tentative Code of Recommended - Practices for Testing and Measur ing Air Flow in Exhaust Systems (1937). AFA 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 ' 1060 CHAiPTER 5.0 '. Table 1. Codes and Standards--(Continued) -1952 Guide Subject ' Title Sponsor Reference . Exhaust Systems Standards for Blower and Exhaust Systems (1949). . NFPA NBFU NFPA No. 91 . Fans Fans Definitions and Terms in Use by the Blower Industry (1950) (Was NAFM Bulletin No. 105). Standard Test Code for Testing Cen trifugal and Axial Fans (1950) (Was' NAFM Bulletin No. 103). NAFM NAFM* ASHVE NAFM Bulletin No. 110 - NAFM ' ; Bulletin No. 110 Fans Standards, Definitions, Terms and - NAFM , Test Codes for Centrifugal, Axial .ASHVE** 'and Propeller Fans.. NAFM Bulletin 110 1950 Fans Standards for Fans (1947). NEMA NEMA Publ. 47-128 Fans Test Code for Fans (1946). ASME ASME PTC 11-1946 . Fire Prevention Budding Code Recommended by the National Board of Fire Underwriters (1943). ' . NBFU ' NBFU Fire Prevention National Fire Codes (1951). NFPA '- NFPA ' Fire Prevention National Fire Code for the Prevention of Dust Explosions (1943). - NFPA - . NFPA _ . Furnaces (Duct) American Standard Approval Re quirements for Gas-Fired Duct Fur naces (1942). A.O.A. : ASA Z21.34-1942 Furnaces (Gas, Floor) Commercial Standard for Gas Floor Furnaces--Gravity Circulating Type (1942). . BS AGAEM . BS * . CS99-42 Furnaces (Gas) - American Standard Approval Re quirements for Central Heating Gas Appliances (1951). A.G.A. ASA Z21.13-1951 Furnaces ' Commercial Standard for Solid-Fuel- - FHA . (Foroed Air, Buraing Forced Air Furnaces (1944). N.W-.A.H. A A.C.A. Solid-Fuel) . AIL BS CS109-44 Furnaces (OilFired) Commercial Standard for Warm Air Furnaces Equipped with Vaporis ing Type Oil Burners (1949). . Mfrs. BS BS . CS104-49 Furnaces (Oil) Commercial Standard for 03 Burn ing Floor Furnaces Equipped with ' Vaporising Type Burners (1951). BS OPA BS . : CS113-51 Furnaces (03) A Tentative Code for Testing 03- Ftred Furnaces. * NWAS A ACA NWAHAACA Garage Ventilation Recommended Good Practice Re quirements for the Construction and Protection of Garages (1932). NFPA NBFU. .. . NFPA No. 88 Garages Code of Minimum Requirements for Heating and Ventilating Garages (1935). ASHVE ASHVE Gas Equipment American Standard Requirements for (Large Boilers) Installation of Gas Equipment in Large Boilers. A.G.A. ASA , , . Z21.33-1950 Gases (Toxic) and Dust American Standard Allowable Con centration of Harmful Gases: . Carbon Monoxide Hydrogen Sulfide Carbon di-sulfide ; Bensene Cadmium ' ASA . ASA ; . Z37.1-1941 ' , Z37.2-1941 . Z37.3-1941 ..... Z37.4-194I Z37.5-1941 Manganese - *- Chromic Arid and Chromates Mercury Metallic Arsenic and Arsenic Tri - oxide 1 Z37.6-1942 Z37.7-1943 Z37.8-1943 Z37.9-1943 . Xylene * Also endorsed by PPMA. ** Refers to Test Code for Centrifugal and Axial Fans. Z37.10-1943 : Codes' and Standards i061 Table 1. Codes and Standards--(Continued) Subject Title Sponsor Gases (Toxic) . and Dust - (Continued) Lead and Certain Inorganic Lead Compounds . Toluene '' Oxides of Nitrogen Methanol Heat Transfer (Walls) . Styrene-Monomer Formaldehyde Methyl Chloride Trichloroethylene ASHVE Standard Test Code for Heat Transmission Through Walls (1928). ASHVE Heaters (Room, Gas Fired) American Standard Approval Re quirements for Gas-Fired Room . Heaters (formerly called Space ' Heaters) (1949 with Addenda 1950). A.G.A. Homes (Pre fabricated) Mineral Wool Commercial Standard for Prefabri cated Homes. Commercial Standard for Mineral Wool Insulation for Heated Indus trial Equipment (1949). PHM1 BS . BS I.M.W.I. Mineral Wool Mineral Wool Commercial Standard for Mineral Wool Insulation for Low Temper ature Installations (194S). Reoommended Commercial Standard for Industrial Mineral Wool Prod ucts--All Types--Testing and Re porting (1946). BS IMWI IMWI BS ' Motors Nema Motor and Generator Stand ards (June 1945). NEMA - Motors Proposed Test Code for Single-Phase Motors (1941). . A1EB Panel System (Warm Air) Pipe A Tubing (Copper A Brass) Piping Piping (Gas) Pumps Code and Manual for the Design'and Installation of Warm Air Ceiling Panel Systems. Simplified Practice Recommendation for Copper Water Tubes and Brass Pipe. ' American Standard Code for Pressure Piping (1942, with Supplement No. 2, 1947). . American Standard for Tptniiatirm of stallation of Gas Piping and Gaa Ap pliances in Buildings (I960). Hydraulic Institute Test Code for Centrifugal Pumps* Hydraulic In stitute Test Code for Rotary Pumps (1943). . NWAH A ACA ASMS A.G.A. m - Radiation (Base IB=R Testing and Rating Code ' board) for Baseboard Type of Radiation (1950). IBR Radiators Code for Testing Radiators (1927). ASHVE Radiators Simplified Practice Recommendation for Cast Iron Radiators (1943). Refrigeration. . Underwriters' Laboratories, Inc., (Equipment) ' Standard for Air Conditioning and Commercial Refrigerating Equip ment (Feb. 1946). * IBR BS UL Refrigeration . American Standard Safety Code for (Mechanical) 1 Mechanical Refrigeration (1939). ASRE Refrigeration Underwriters' Laboratories, Inc., (Unit Systems) Standard for Unit Refrigerating Systems (Feb. 1946). UL Refrigerators (Gas-Fired) American Standard Approval Re quirements for Refrigerators Using Gaa Fuel (1941). *** Also designated A8RE Circular No. 15. A.QJL. Reference Z37.11-1843 - Z37.12-1943 Z37.13-1944 Z37.14-1944 Z37.15-1944 Z37.16-1944 Z37.18-1949 Z37.19-1946 ASHVE . * ASA Z21.11-1949 BS CS125-47 BS CS117-49 BS CS105-48 BS C8131-46 : NEMA . 45-102 AIBB NWAH A ACA Manual No. 7-A BS R217-49 ASA B31.1-1942 ASA Z21.30-1950 HI Section F IBR ASHVE BS R174-47 UL Subject 207A 1 ASA B9-1939*** UL 'Subject 207C . ASA ' . Z21.19-1941 1062 CHAPTER SO . 1952 Guide Table 1. Codes and Standards--(Continued) Subject - . Title ' 6ponsob Reverence Refrigerators. (Household) American Standard Test Procedures for Household Electric Refriger ators (Mechanically Operated) (1944). . . ASRE___ USDA T- ASA B38.2-1944 ; Sound (Measurement) Sound - v (Measurement) American Standard for-Noise Measurrinent. American Standard for Sound Level Meters for Measurement of Noise and Other Sounds. . AS of A AS of A ASA Z24.2-1942 ASA Z24.3-1944 Sound . _ American Standard Method for the . - 4So/4 (Measurement) Pressure Calibration of Laboratory Standard Pressure Microphones. ` ASA Z24.4-1938 Sound ` Sound. Measurement Test Code for (Measurement) Centrifugal and Axial Fans (1950) (Was NAFM Bulletin No. 104). . NAFM NAFM Bulletin No. 110 (1950) Space Heaters Commercial Standard for Flue Con nected Oil-Burning Space Heaters Equipped with Vaporizing . Pot- Type Burners (1943). ICHAM . BS CS101-43 3. - \ * Stokers Code for Determination of Rated Ca- parities of Anthracite Underfeed Stokers (1944). SMA " . SMA Stokers Code for Determination of Rated Ca pacities of Bituminous Underfeed Stokere (1944). .. SMA " SMA Stokers Recommended Minimum Firebox ; SMA . . Dimensions and Base Heights (1944). SMA Stokers Recommended Standards Governing Minimum Setting Heights (1944). - SMA ` SMA Tubing (Seam Simplified Practice Recommendation less Copper for Copper and .Copper-Alloy. and Copper Air - Round Seamless Tube (1948). loy) Mfra. ' BS . ... BS R235-48 Tubing (Seam Standard Specifications for Seamless less Copper Copper Water Tube (1951).. . Water Tube) , ASTM , . .i.- - ASA. H23.1-1951 Unfired Pressure Unfired Pressure Vessel Code (1950). Vessels .ASMS . .- ASMS Unit Heaters American Standard Approval Requiremente for Gas Unit Heaters (1940). A.G.A. ASA . Z21.26-1940 Unit Heaters. Standard Code for Testing and Rating , ASHVE Steam Unit Heaters (1950). .. ., IUHA '. . ASHVE - IUHA Bulletin 10 . Unit Heaters Proposed Standard Code for Testing Hot Water Unit Heaters (1942). IUHA IUHA Unit Ventilators A.S.H.VJE. Standard Code for Testing and Rating Steam Unit Ventilators (1934). . ASHVE ASHVE - Vacuum Pumpe A.S.H.V.E. Standard Code for Test ing and Rating Return Line Low Vacuum Heating Pumps (1934). . ASHVE . ASHVE . Warm Air (Gravity) - Gravity Code and Manual for the De sign and Installation of Gravity Warm Air Heating Systems (147). NWAH & ACA NWAHA ACA Section No. 5 Water Heaters American Standard Household Auto matic Electric Storage-type Water Heaters. NBMA . ASA . C72.1-1949 Water Heaters American Standard Approval Re quirements for Gas Water Heaters (1950). A.G.A. . ASA Z21.10-1950' Water Heaters NBMA Standards for Electric Water Heaters (1945). . NBMA . ' NBMA 45-104 Code's and Standards " . .. 1063 Table X. Codes and Standards (Concluded) Subject ' Water Heaters Wiring ; Wiring Title ` . ` Testing and Rating Hand-Fired Hot Water Supply Boilers (1948). Interior Wiring Design for Commer . cial Buildings. National Electrical Code, Standard of NBFU and NFPA (1947, with 1949 Supplement). Sponsob fha - AIBB ... NBFU NFPA Reference ' . bs : CS145-47 AIBB ` 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 A.G.A. AQAEM Air Conditioning Manufacturers Association, superseded 1940 by ACRMA. Air Conditioning and Refrigerating Machinery Association, Southern Bldg., Wash* ington, D. C. . American Foundrymen's Association; 222 W. Adams St., Chicago, 111. American Gas Association, 420 Lexington Ave., New York, N. Y. , Association of Gas Appliance and Equipment Manufacturers, superseded 1945 by AlA AIBB AIL ASA AS of A .ASHVE . . ' ASMS ASRE . ASTM BOCA BOB BS CMA FHA .GAMA . HI HP A ACCNA IBR ICHAM 1MWI IUHA NAFM NBFU .. NBMA NFPA / NHA ! NRC / NWAH A ACA OBI OHIA \ OPA PC PFMA PHMl REMA . RMA SAB SBI . SMA TEMA UL USDA USPHS 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. Anthracite Industries Laboratory, 237 Old River Rd., Wilkes Barre, Pa. American Standards Association, 70 East 45th St., New York, N. Y. 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 39th 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. 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. . ' 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. Hydraulic Institute, 90 West St., New York, N. Y. ' Heating, Piping and Air Conditioning Contractors National Association, 1250 Ave nue of the Americas, New York, 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 Wool Institute, 441 Lexington Ave., New York, N. Y. - Industrial Unit Heater Association, 2157 Guardian Bldg.,- Detroit, Mich. -National Association of Fan Manufacturers, 2159 Guardian Bldg., Detroit, Mich. 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. . National Warm Air Heating and Air Conditioning Association, 145 Public Square, Cleveland, Ohio. . . Oil Bumer Institute, superseded 1942 by OHIA ; '- Oil Heat Institute of America, 6 East 39th St., New York, 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, SOS 20th St., N.W., Washington, D. C. Refrigeration Equipment Manufacturers Association, 1346 Connecticut Ave., N.W., Washington 6, D. C. .. 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. 1064 CIHA" PTER SO Table ? -Circumferences and Areas of Circles 1952 .Guide Diameter IN Inches ;. Area ' Sqln. 8qFt Circumference Inches Feet Diameter in Inches Area . Circumference ' Sq In. Sq Ft 1 Inches - ' Feet" H l IX IH iX `2 2X2H 2^ 3 3>? 4 *X 4H 4H s N 5X SH 6 6K 6H 65* 7 IX 8 85* 8J* SM 9 ?>* 9H 9X 10 . WH 11 IlM 12 I2M 13 i*M 14 UK 15 I5H 16 16H 17 . tw 18 mi 19 19H 20 20H 21 21 a 22 22H 23 23H 24 2<H 25 2SM 26 26H 27 2?M 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 5L939 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 . 18.06 28.27 0.1964 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 56.73 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 s103.9 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 .S5 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 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 0.1964 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, 28 615.8 4.276 28H 637.9 4.430 29 660.52 4.587 29M .683.5 4.747 30 706.8 4.909 31 754.8 5.241 1 32 804.3 5.585 .33 v 855.3- 5.940 ; 34 907.9 6.305 35 962.1 6.681 36 1018.0 , 7.069; 37 . 1075.0 7.467 - 38 1134.0 7.876 . 39 1195.0 . 8.296 40 1256.0 8.727 41 . 1320.0 9.168 42 1385.0 9.621 . 43 1452.0 10.08 44 1521.0 10.56 45 1590.0 11.04 46 1662.0 11.54 :v47 1735.0 12.05 48 1810.0 12.51 49 - 1886.0 13.09 50 1963.0 13.64 51 2043.0 14.19 52 2124.0 14.75 S3 2206.0 15.32 54 2290.0 15.90 55 2376.0 16.50 . 56 2463.0 . 17.10 . 57 2552.0 17.72 58 2642.Q 18.35 59 2734.0. 18.99 60 .2827.0 19.63 61 2922.0 20.29 62 3019.0 20.97 63 3117.0 21.65 64 . . 3217.0 22.34 . 65 . 3318.0 23.04 66 3421.0 23.76 67 . 3526.0 24.48 68 3632.0 25.22 .69 3739.0 25.97 70 3848.0 26.73 71 39S9.0 27.49 72 4072.0 28.27 73 * 4185.0 29.07 74 . 4301.0 29.87 75 4418.0 30.68 . 76 4536.0 31.50 77 4657.0 32.34 78 . ;4778.0. 33.18 79 4902.0 ' 34.04 80 5027.0 34.91' 81 5153.0 35.78 82 528t.0 36.67 83 5411.0 37.57 84" 5542.0 38.48 85 5675.0 39.41 86 5809.0 40.34 87 5945.0 41.28 88 6082.0 42.24 89 6221.0 43.20 90 6362.0 44.18 91 -6504.0 45.17 92 6648.0 46.16 93 6793.0 47.17 -94- 6940.0 48.19 95 . 7088.0 - 49.22 96 7238.0 .50.27 97 7390.0 51.32 98 7543.0 52.38 99 7698.0 53.46 100 7854.0 54.54 . 87.97 89.54 91.11 92.63 94.25 97.39 100.5 103.7 106.8 109.9 .. 1I3.1116.2 119.4 122.5 125.6 128.8 131.9 135.1 138.2 141.4 144.5 147.7 150.8 153.9 . 157.1 160.2 163.4 166.5 169.6 172.8 175.9 179.1 182.2 185.4 188.S 391.6 194.8 197.9 201.1 204.2 207.3 210.5 213.6 216.8 219.9 223.1 226.2 229.3 232.5 235.6 238.8 241.9 245.0 248.2 -251.3 254.5 257.6 260.8 263.9 267.0 270.2 273.3 . 276.5 279.6 282.7 285.9 289.0 292.2 295.3 298.4 301.6 304.7 307.9 311.0 - 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.S2 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 '23.30 23.56 23.82 24.09 24.35 24.61 24.87 25.13 25.39 25.66 25.92 .26.18 CATALOG DATA SECTION INDEX TO ADVERTISERS PAGE 1067 INDEX TO MODERN EQUIPMENT PAGE 1073 / V. INDEX TO ADVERTISERS HEATING VENTILATING AIR CONDITIONING GUIDE, 1952 A . Page ACE ENGINEERING CO., 1435 West 15th St., Chicago 8, HI............................ 1382 ACME INDUSTRIES, INC., Jackson, Mich........................................................ .. 1216 AEROFIN CORP., 410 S. Geddes St., Syracuse 1, N. Y..................... 1217-1218-1219 AIR & REFRIGERATION CORP., 475 Fifth Ave., New York 17, N. Y........... ... 1099 AIR CONTROL PRODUCTS, INC., Coopersville, Mich............................... 1264-1265 AIR DEVICES, INC., 17 East 42nd St., New York 17, N. Y................. 1178, 1263 AIR FILTER CORP., 108G N. Water St., Milwaukee 2, Wis....................... ......... 1179 AIR-MAZE CORP., 5200 Harvard Ave., Cleveland, Ohio......................... 1180-1181 AIR-MAZE CORP., DETROIT AIR FILTER DIV., 5200 Harvard Ave., Cleve land, Ohio.................................................................................................................... 1182 AIRTHERM MFG. CO., 728 S. Spring Ave., St. Louis 10, Mo............................... 1141 ALADDIN HEATING CORP., 2272 San Pablo Ave., Oakland 12, Calif............. 1234 ALCO VALVE CO., 851 Kingsland Ave., St. Louis 5, Mo..................................... 1299 ALDRICH CO., 121 E. Williams St., Wyoming, 111.................................................. 1332 AMERICAN AIR FILTER CO., INC., HERMAN NELSON DIVISION, 673 Central Ave., Louisville 8, Ky...................................................... 1183-1184-1185 AMERICAN ARTISAN (publication), 6 N. Michigan Ave., Chicago 2, 111......... 1490 AMERICAN BLOWER CORP., P. O. Box 58, Roosevelt Park Annex, Detroit 32, Mich...................................................................................................................... 1100-1101 AMERICAN BRASS CO., THE, Waterbury 20, Conn..................................... 1174-1175 AMERICAN COOLAIR CORP., 3606 Mayflower St., Jacksonville 3, Fla................ 1235 AMERICAN FLANGE & MFG. CO., 30 Rockefeller Plaza, New York 20, N. Y. 1480 AMERICAN FOUNDRY & FURNACE CO., P. O. Box 904, Bloomington, 111..................................................... .................................................................... 1120-1121 AMERICAN FURNACE CO., 1300 Hampton Ave., St. Louis 10, Mo................... 1122 AMERICAN MOISTENING CO., Providence 1, R. 1.............................................. 1214 AMERICAN RADIATOR & STANDARD SANITARY CORP., P. O. Box 1226, Pittsburgh 30, Pa........................................................................... 1328-1329-1330-1331 AMERICAN SOCIETY OF REFRIGERATING ENGINEERS, 40 West 40th St., New York 18, N. Y........................................................................................... 1486 AMERICAN SOLVENT RECOVERY CORP., Cassady & 8th Aves., Columbus 3, Ohio. .. 1186-1187 AMERICAN STRUCTURAL PRODUCTS CO., SUB. of OWENS-ILLINOIS GLASS CO., Toledo 1, Ohio................................................................................... 1460 1 AMERICAN 3 WAY-LUXFER PRISM CO., 431 S. Dearborn St., Chicago 5, IU..................................................................................................................................... 1461 V. D. ANDERSON CO., THE, 1960 West 96th St., Cleveland, Ohio........ 1410-1411 494]. ANEMOSTAT CORP. OF AMERICA, 10 East 39th St., New York 16, N. Y. 1266-1267 APRIL SHOWERS CO., INC., 4126 Eighth St., N.W., Washington 11, D. C.... 1459 m ARMSTRONG CORK CO., BuUding Materials Dlv., Lancaster, Pa................... 1464 ARMSTRONG MACHINE WORKS, 851 Maple St., Three Rivers, Mich.. 1412-1413 AUER REGISTER CO., THE, 6600 Clement Ave., Cleveland 5, Ohio.................. 1268 AURORA PUMP CO., 40 Loucks St., Aurora (Chicago Suburb), HI................... 1401 AUTOMATIC BURNER CORP., 1823 W. Carroll Ave., Chicago 12, IU............... 1383 AUTOMATIC GAS EQUIPMENT CO., Brushton & Thomas St., Pittsburgh 21, Pa.................................................................................................................:......... 1151 B BABCOCK & WILCOX CO., THE, 85 Liberty St., New York 6, N. Y.................... 1352 BADGER MFG. CO., 230 Bent St., Cambridge 41, Mass......................................... 1293 BAHNSON CO., THE, Winston-Salem, N. C..................................................... 1102-1103 BAKER REFRIGERATION CORP., South Windham, Maine.......:.............. 1225 BALTIMORE AIRCOIL CO., INC., 2615 Mathews St., Baltimore 18, Md........ 1226 BARBER-COLMAN CO., 150 Loomis, Rockford, 111.........................i........................ 1269 BARNES & JONES, INC., 128 Brookslde Ave., Boston 30, Mass....................... 1409 BAYLEY BLOWER CO., 1821 S. Sixty-Sixth St., MUwaukee 14, Wls................ 1236 BELL & GOSSETT CO., Morton Grove, III. . ............................................... 1396-1397 BINKS MFG. CO., 3130-36 Carroll Ave., Chicago 12, IU................................. 1206-1207 BISHOP & BABCOCK MFG. CO., THE, MASSACHUSETTS BLOWER DIV., 4901 Hamilton Ave., Cleveland 14, Ohio................................................................ 1237 G. C. BREIDERT CO., 3129 San Fernando Rd., Los Angeles 65, CaUf................ 1258 BROWN PRODUCTS CO., 97-12 MetropoUtan Ave., Forest HlUs, N. Y.:........ 1333 1067 1068 1952 Guide Page BRYAN STEAM CORP., Chili Pike, Peru, Ind........................................................ BUENSOD-STACEY, INC., 60 East 42nd St., New York 17, N. Y....................... BUFFALO FORGE CO., 450 Broadway, Buffalo, N. Y.......................................... BUFFALO PUMPS, INC., 450 Broadway, Buffalo, N. Y............................... BURNHAM CORP., Irvington-on-Hudson, N. Y...................................................... 1334 1104 1238 1402 1335 C E. K. CAMPBELL CO., 1809 Manchester, Kansas City 3, Mo............................. 1143 CAMPBELL HEATING CO., 3121 Dean, Des Moines 17, Iowa........ 1124-1125, 1142 CAM-STAT, INC., DIV. of the PAUL HENRY CO., 11831 W. Olympic Blvd., Los Angeles 64y Calif................................................................................................ 1300 PHILIP CAREY MFG. CO., THE, Lockland, Cincinnati 15, Ohio............ 1448-1449 CARRIER CORP., Syracuse 1, N. Y................................................................. 1106-1107 CARTY & MOORE ENGINEERING CO., 1150 W. Baltimore Ave., Detroit 2, Mich............................................................................................................................... 1414 CELOTEX CORP., THE, 120 S. LaSalle St., Chicago 3, III................................. 1466 CHAMPION BLOWER & FORGE CO., Div. 9, Lancaster, Pa.......................... 1239 CHICAGO METAL HOSE DIVISION, FLEXONICS CORP., Maywood, III.. 1176 CHICAGO PUMP CO., 2330 Wolfram St., Chicago 18, 111.................................. 1403 CHICAGO STEEL FURNACE CO., 9326 S. Anthony Ave., Chicago 17, 111.... 1146 CHRYSLER AIRTEMP, DIV. of CHRYSLER CORP., Dayton 1, Ohio.... 1126-1127 CLARAGE FAN CO., Kalamazoo, Mich.................................................................... 1105 CLAYTON & LAMBERT MFG. CO., Louisville 10, Ky........................................ 1123 CLEAVER-BROOKS CO., 465 E. Keefe Ave., Milwaukee 12, Wis.................... 1353 COAL-HEAT (publication), 20 W. Jackson Blvd., Chicago 4, 111......................... 1487 COMBUSTION CONTROL CORP., 77 Broadway, Cambridge 42, Mass......... 1301 COMBUSTION ENGINEERING-SUPERHEATER, INC., 200 Madison Ave., New York 16, N. Y........................................................................................... 1354-1355 W. B. CONNOR ENGINEERING CORP., Shelter Rock Lane, Danbury, Conn............................................................... ................. 1188-1189-1190-1191, 1270-1271 CONTINENTAL AIR FILTERS, INC., P.O. Box 1647, Louisville, Ky................... 1192 CRANE CO., 836 S. Michigan Ave., Chicago 5, 111........................................ 1336-1337 CURTIS REFRIGERATING MACHINE DIV. of CURTIS MFG. CO., 1959 Kienlen Ave., St. Louis 20, Mo.............................................................................. 1227 CYCLOTHERM CORP., Oswego, N. Y.................................................................. 1356 D DE BOTHEZAT FANS DIV., AMERICAN MACHINE & METALS, INC., East Moline, 111.................................................................................................................... 1240 CHARLES DEMUTH & SONS, INC., 245 Elm Place, Mineola, N. Y............. 1272 DETROIT REGULATOR CO., 1742 Rivard St., Detroit 7, Mich........................ 1302 DEWEY-SHEPARD BOILER CO., THE, Sales Office, 1311 N. Capitol Ave., Indianapolis, Ind.................................................................... 1357 DIAMOND MFG. CO., 253 West 8th St., Wyoming, Pa....................................... 1273 DOLE VALVE CO., THE, 1933 Carroll Ave., Chicago 12, 111................. ........... 1443 DOLLINGER CORP., 6 Centre Pk., Rochester 3, N. Y.............................. 1194-1195 DOMESTIC ENGINEERING (publications), 1801 Prairie Ave., Chicago 16, 111. 1488 DRAVO CORP., Heating Dept., Dravo Bldg., Fifth & Liberty Aves., Pitts burgh 22, Pa....................................................................................................... 1144-1145 C. A. DUNHAM CO., 400 West Madison St., Chicago 6, HI............................... 1415-1416-1417-1418-1419 DURANT INSULATED PIPE CO., 1015 Runnymede St., P. O. Box 88, Palo Alto, Calif................................ 1453 DUTTON BOILERS, DIVISION HAPMAN-DUTTON CO., 639 Gibson St., Kalamazoo, Mich.......................................... 1358 E ELECTRIC AUTO-LITE CO., THE, Instrument & Gauge Div., Dept. HV, Toledo 1, Ohio............................................................................................................ ELECTROMODE CORP., 45 Crouch St., Rochester 3, N. Y............................... ENTERPRISE ENGINE & MACHINERY CO., A SUBSIDIARY of GEN ERAL METALS CORP., 18th and Florida Sts., San Francisco 10, Calif... 1303 1152 1384 F FAIRBANKS CO., THE, 393 Lafayette St., New York 3, N. Y........................... 1444 FARR COMPANY, P. O. Box 10187, Airport Sta., Los Angeles 45, Calif.... 1196-1197 FARRAR & TREFTS, INC., 20 Milbum St., Buffalo 12, N. Y........................... 1359 FEDDERS-QUIGAN CORP., 57 Tonawanda St., Buffalo 7, N. Y....................... 1153 FIELD CONTROL DIVISION of H. D. CONKEY & CO., Press Bldg., Mendota, I1L............................................................................................................... 1308 Index to Advertisers 1069 Page FITZGIBBONS BOILER CO., INC., 101 Park Ave., New York 17, N. Y... 1360-1361 FLEXONICS CORPORATION, EXPANSION JOINT DIVISION, (formerly Chicago Metal Hose Corp.,Maywood, 111.)......................... 1294 FLUID SYSTEMS, INC., 1881 Dlxwell Ave., New Haven 14, Conn......... 1376-1377 FLUOR CORP., LTD., THE, 2500 S. Atlantic Blvd., Los Angeles 22, Calif.,. 1208 FOSTER WHEELER CORP., 165 Broadway, New York 6, N. Y........................ 1209 FRICK CO. (Inc.), Waynesboro, Pa.................................................................. 1228 FRIGIDAIRE, DIVISION OF GENERAL MOTORS, Dayton 1, Ohio............. 1110 FULTON-SYLPHON DIVISION, ROBERTSHAW-FULTON CONTROLS CO., Knoxville 4, Tenn................................................................................... 1304-1305 G G & O MANUFACTURING CO., THE, 138 Winchester Ave., New Haven 8, Conn.......................................................................................................... GENERAL AUTOMATIC PRODUCTS CORP., 2300 Sinclair Lane, Baltimore 13, Md........................................... :................................................................... ......... GENERAL BLOWER CO., 8600 Ferris Ave., Morton Grove, 111......................... 1220 1338 1241 UD11 DXUtD GL/it 1AV/DO) OUi AI1CU /iVC., VTltimifllff 1, ........................................... lOUP--1JW -GENERAL ELECTRIC CO., Air Conditioning Div., Bloomfield, N. J___ 1108-1109 GLASFLOSS CORP., 155 East 44th St., New York 17, N. Y............ .................. 1193 GRINNELL CO., INC., Providence 1, R. 1..................................................... 1154-1155 GUSTIN-BACON MFG. CO., 210 West 10th St., Kansas City, Mo................... 1450 H HAMMOND BRASS WORKS, Summer Blvd., Hammond, Ind........................... 1445 ARTHUR HARRIS & CO., 210-218 N. Aberdeen St., Chicago 7, 111................. 1295 luiai u< iur\j uuiituiU) luiviii............................................................................. j HARTZELL PROPELLER FAN CO., DIV. of CASTLE HILLS CORP., Plqua, Ohio......................................................................................................... 1242 HASTINGS AIR CONDITIONING CO., INC., Hastings, Nebr........................ 1111 HAYES FURNACE MFG. & SUPPLY CO., 2929 S. Fairfax Ave., Los Angeles 16, Calif................................................................. 1128 HEATING & PLUMBING EQUIPMENT NEWS (publication), 148 Lafayette St., New York 13, N. Y............................................................................................. 1489 HEATING and VENTILATING (publication), 148 Lafayette St., New York 13, N. Y................................................................................................................................ 1489 HEATING, PIPING and AIR CONDITIONING (publication), 6 N. Michigan Ave., Chicago 2, 111.............................. 1490 HENDRICK MFG. CO., 48 Dundaff St., Carbondale, Pa........................... 1276-1277 HENRY VALVE CO.,Melrose Park, HI....................................................................... 1309 HIRSCHMAN-POHLE CO., INC., 200 Lent Ave., Le Roy, N. Y..................... 1259 HOFFMAN SPECIALTY CO., 1001 York St., Indianapolis 7, Ind...................... 1420-1421-1422-1423 HOMESTEAD VALVE MFG. CO., P. O. Box 127, Coraopolis, Pa...................... 1446 HOOK & ACKERMAN, INC., 9 East 40th St., New York 16, N. Y.. ............. 1339 HUBBELL CORP., P. O. Box 700, Hawley Road, Mundelein, 111...................... 1310 HUNTER FAN AND VENTILATING CO., P. O. Box 2858, Desoto Sta., 400 S. Front St., Memphis 2, Tenn....................................................................... 1243 I ILG ELECTRIC VENTILATING CO., 2880 N. Crawford Ave., Chicago 41,111. 1156,1244 *"w**,v*w ajli VJill DDXvlli V v \7y vuIVttgU Oy 1U> ....................... ATE*4 ILLINOIS TESTING LABORATORIES, INC., Room 516, 420 N. LaSalle St., INDEPENDENT REGISTER CO., THE, 3747 East 93rd St., Cleveland 5, Ohio 1278 INFRA INSULATION, INC., 525 Broadway, New York, N. Y............................ 1482 INGERSOLL PRODUCTS DIV., BORG-WARNER CORP., 321 S. Plymouth Ct,, Chicago 4, 111....................................................................................................... 1481 INGERSOLL-RAND, 11 Broadway, New York 4, N. Y........................................... 1404 INSULITE DIVISION, MINNESOTA and ONTARIO PAPER CO., 500 Baker Arcade Bldg., Minneapolis 2, Minn............................................................. 1468-1469 INSUL-MASTIC CORP. OF AMERICA, 1162 Oliver Bldg., Pittsburgh 22, Pa. 1467 INTERNATIONAL BOILER WORKS CO., THE, 500 Birch St., East Stroudsburg, Pa....................................................................................... 1362 INTERNATIONAL EXPOSITION CO., Grand Central Palace, New York 17, T N. Y........................................................................................ 1395 IRON LUNG VENTILATOR CO., 4013 Prospect Ave., Cleveland 3, Ohio.... 1260 J JENKINS BROS., 100 Park Ave., New York 17, N. Y............................................ 1447 JENN AIR PRODUCTS CO., 333 N. Pennsylvania Ave., Indianapolis 4, Ind. 1245 1070 1952 Guide _ Page JOHNS-MANVILLE, 22 East 40th St., Hew York 16, N. Y................. . 1470-1471 S. T. JOHNSON CO., 940 Arlington Ave., Oakland 8, Calif.................... 1386-1387 JOHNSON SERVICE CO., Milwaukee, Wis................................................... 1312-1313 JOHNSTON BROS., INC., Ferrysburg, Mich..................... ~........................... 1363 JOY MFG. CO., General Offices, Henry W. Oliver Bldg., Pittsburgh 22, Pa. 1246-1247 KENNARD CORP., 1819 S. Hanley Rd., St. Louis 17, Mo................. .............. 1157 KEWANEE BOILER CORP., Kewanee, Hi.................................. 1364-1365-1366-1367 KIMBERLY-CLARK CORP., Neenah, Wis............. :................... ................... 1472-1473 KRITZER RADIANT COILS, INC., 2909A Lawrence Ave., Chicago 25, HI........ 1222 L LADISH CO., Cudahy, Wis........................................................................................... LAD BLOWER CO., THE, 2007 Home Ave., Dept. H, Dayton 7, Ohio............ LEE CORP., 1001 TatnaU St., Wilmington, Del....................................................... LILIE-HOFFMANN COOLING TOWERS, INC., 4239 Duncan Ave., St. Louis 10, Mo......................................................................................................................... H. C. LITTLE BURNER CO., San Rafael, Calif.................................................. LOCKPORT COTTON BATTING CO., Lockport, N. Y........................................ 1296 1248 1147 1210 1385 1474 ,M MAID-O'-MIST, INC., 3217 N. Pulaski Rd., Chicago 41, HI..................... 1426-1427 MARLEY CO., INC., THE, 222 W. Gregory, Kansas City 5, Mo........................... 1211 MARLO COIL CO., 6135 Manchester Ave., St. Louis 10, Mo............................., 1229 JAS. P. MARSH CORP., Dept. 5, Skokie, HI................................................ 1428-1429 McCORD CORP., Air Conditioning & Refrigeration Div., Detroit 11, Mich... 1162 McDONNELL & MILLER, INC., 3500 N. Spaulding Ave., Chicago 18, HI....................................................................................................... 1372-1373-1374-1375 McQDAY, INC., 1602 Broadway, N.E., Minneapolis 13, Minn............. .. 1158-1159 MERCOID CORP., THE, 4201 Belmont Ave., Chicago 41, HI............................. 1314 MEYER FURNACE CO., THE, Peoria 1, 111.................................................. 1130-1131 MILLS INDUSTRIES, INC., 4100 Fullerton Ave., Chicago 39, 111. .................. 1230 MILWAUKEE GAS SPECIALTY CO., 730 N. Jackson St., Milwaukee 2, Wis. 1315 MINNEAPOLIS-HONEYWELL REGULATOR CO., 2644 Fourth Ave., So., Minneapolis 8, Minn..................................... 1316-1317 MODINE MFG. CO., 1515 Dekoven Ave., Racine, Wis............................... 1160-1161 MOELLER INSTRUMENT CO., 132nd St. and 89th Ave., Richmond Hill 18, N.Y........................... :.................................................................................................. 1318 MONARCH MFG. WORKS, INC., 2500 E. Ontario St., Philadelphia 34, Pa... 1215 MORRISON PRODUCTS, INC., East 168th St. and Waterloo Rd., Cleveland 10, Ohio........................................................................................................ 1249 L. J. MUELLER FURNACE CO.,Milwaukee 15, Wis.................................. 1132-1133 MUNDET CORK CORP., Insulation Dlv., 7105 Tonnelle Ave., North Bergen, N. J..................................................................................................................................... 1465 D. J. MURRAY MFG. CO.,Wausau, Wis................................................................ 1163 N. NASH ENGINEERING CO., THE, 234 Wilson Rd., South Norwalk, Conn. 1406-1407 NATIONAL HEATER CO., 2182 Cleora Ave., St. Paul 4, Minn............... 1148-1149 NATIONAL RADIATOR CO., THE, Johnstown, Pa...................................... 1340-1341 HERMAN NELSON DIVISION of the AMERICAN AIR FILTER CO., INC., Moline, 111........................................................................................................... 1164-1165 JOHN J. NESBITT, INC., Philadelphia 36, Pa............................. ......................... 1166 NEW YORK BLOWER CO., THE, 32nd St. & Shields Ave., Chicago 16, 111. 1250 NIAGARA BLOWER CO., 405 Lexington Ave., New York 17, N. Y.. .......... 1112 W. H. NICHOLSON & CO., 211 Oregon St., Wilkes-Barre, Pa.............. 1430-1431 NORGE HEAT, DIVISION OF BORG-WARNER CORP., 672 E. Woodbridge, Detroit 26, Mich................................................................................. ............. 1134-1135 O OHIO BRASS CO., Mansfield, Ohio............................................... ............... .......... 1432 ARTHUR A. OLSON & CO., Broad and Court Sts., Canfield, Ohio................ 1150 OWENS-CORNING FIBERGLAS CORP., Toledo 1, Ohio....................... 1198, 1451 OWENS-ILLINOIS GLASS CO., Kaylo Div., Toledo 1, Ohio............................. 1475 ;' P ., PACIFIC LUMBER CO., THE, 100 Bush St., San Francisco 4, CaUf............. 1478 PACIFIC STEEL BOILER DIV., U.S. RADIATOR CORP., Detroit 31, Mich..................................................................................................................... 1342-1343 Index to Advertisers 1071 Page PARKS-CRAMER CO., Fitchburg, Mass......................................................... 1114-1115 PATTERSON-KELLEY CO., THE, 101 Burson St., East Stroudsburg, Pa.. . 1221 PEERLESS PUMP DIVISION, FOOD MACHINERYAND CHEMICAL CORP., Ovl Wt$al nVCUUv AUy DVD AllgClvS vlf walil.................................... . ................................................. IWw PENN CONTROLS, INC., Goshen, Ind.................................................................... 1319 PERFEX CORP., Milwaukee 7, Wis.......................................................................... 1320 rainoi/AUiu iiaai u rvircR ouuuiuru, v,umi...................................looo-iooy PITTSBURGH CORNING CORP., Room U52, 307 Fourth Ave., Pittsburgh 22, Pa................................................................................................................... 1462-1463 PITTSBURGH LECTRODRYER CORP., Foot of 32nd St., P. O. Box 1766, Pittsburgh 30, Pa....................................................................................................... 1113 PLUMBING AND HEATING JOURNAL (publication), 92 Martllng Ave., X til Iy i\/WII| 1*....................................................................................................................................... Ixfl H. W. PORTER & CO., INC., 817-G Frellnghuysen Ave., Newark 5, N. J.. 1454 POWERS REGULATOR CO., THE, General Office and Factory, 3400 Oakton St., Skokie, HI............................................................................................................ 1321. J. F. PRITCHARD & CO., Equipment Div., Dept. 230, 908 Grand Ave., Kansas City 6, Mo.............. ....................................................................................................... 1212 PROPELLAIR DIVISION, ROBBINS & MYERS, INC., 1947 Clark Blvd., opnugueiUf vmu......................................................................................................................................................................... iaoi FRANK PROX CO., INC., 1201 S. First St., Terre Haute, Ind......................... 1346 PYLE-NATIONAL CO., THE, Multi-Vent Dlv., 1363-78 N. Kostner Ave., R RAY OIL BURNER CO., 1301 San Jose Ave., San Francisco 12, Calif....... 1390-1391 C. L. RAYFIELD CO., 2010-18 S. Halstead St., Chicago 8, HI........................... 1392 READY-POWER CO., THE, 11231 Freud Ave., Detroit 14, Mich...................... 1231 REFLECTAL CORP., 155 East 44th St., New York 17, N. Y............................... 1483 REFRIGERATION APPLIANCES, INC., 923 W. Lake St., Chicago 7, 111.... 1232 REFRIGERATION ECONOMICS CO., INC., 1231 Tuscarawas St. E., Canton 2, Ohio.......................................................... 1167 REFRIGERATION ENGINEERING, INC., 7250 E. Slauson Ave., Los Angeles 22, Calif......................................................................................................................... 1233 REGISTER & GRILLE MFG. CO., INC., 70 Berry St., Brooklyn 11, N. Y.. 1279 RESEARCH PRODUCTS CORP., Madison 10, Wis............................................. 1199 REVERE COPPER & BRASS, INC., 230 Park Ave., New York 17, N. Y..... 1177 RHEEM MFG. CO., 570 Lexington Ave., New York 22, N. Y.................. ........... 1136 RIC-WIL CO., THE, Union Commerce Bldg., Cleveland, Ohio......................... 1455 ROCHESTER MFG. CO., INC., 80 Rockwood St., Rochester 10, N. Y........... 1322 ROME-TURNEY RADIATOR CO., THE, Erie Blvd., East, Rome, N. Y........ 1223 S wrxivw WM UU/.t ikUipiie OlttlC DIUg., AVCW Ullh X, 11. ........................................... 1*0`-110*J SARCOTHERM CONTROLS, INC., Empire State Bldg., New York 1, N. Y. 1433 SERVEL, INC., Air Conditioning Div., Evansville, Ind......................................... 1137 SHAW-PERKINS MFG. CO., 201 E. Carson St., Pittsburgh 19, Pa................. 1347 SHEET METAL WORKER (publication), 92 Martllng Ave., Tarrytown, N. Y.. 1491 SILVERCOTE PRODUCTS, INC., 161 E. Erie St., Chicago 11, HI.................. 1484 SIMPLEX MFG. CO., 198-206 N. Main St., Fond du Lac, Wis.......................... 1323 SKIDMORE CORP., St. Joseph, Mich...................................................................... 1408 H. B. SMITH CO., INC., THE, Westfield, Mass.................................................. 1350 SNIPS MAGAZINE (publication), 5707 W. Lake St., Chicago 44, 111................ 1492 H. J. SOMERS, INC., 6063 Wabash Ave., Detroit 8, Mich........................ 1200-1201 SONNER-BURNER CO., 412-420 East 6th Ave., Winfield, Kansas................... 1378 SPENCE ENGINEERING CO., INC., 28 Grant St., Walden, N. Y.................. 1324 SPENCER HEATER, LYCOMING-SPENCER DIVISION--AVCO MFG. SPRAYO-FLAKE INSULATION COi, 2727 Irving Park Road, Chicago 18, STANDARD STAMPING & PERFORATING CO., 3111 West 49th Place, Chicago 32, 111..........................................!................................................................. 1282 STERLING, INC., 3738 N. Holton St., Milwaukee 12, Wis................................. 1325 STEWART MFG. CO., INC., Cedar Grove, N. J.................................................. 1283 STRONG, CARLISLE & HAMMOND CO., 1392 W. Third St., Cleveland 13, Ohio............................................................................................................................... 1436 SWARTWOUT CO., THE, 18511 Euclid Ave., Cleveland 12, Ohio.................... 1261 SYNCROMATIC CORP., 1141 Tenth St., Watertown, Wis.................................. 1129 1072 1952 Guide Page T TACO HEATERS, INC., 137 South St., Providence 3, R. 1................................. 1400 Taylor forge & pipe works, inc., p. o. box 4ss, Chicago 90, in... 1297 TAYLOR INSTRUMENT COMPANIES, Rochester 1, N. Y.......................... . 1326 H. A. THRUSH & CO., Peru, Ind.................................................................... 1398-1399 TITUS MFG. CORP., 113 East 8th St., Waterloo, Iowa............................. 1284-1285 TITUSVILLE IRONWORKS CO., THE, DIV. of STRUTHERS WELLS CORP., Titusville, Pa........................................................................................................... :. 1368 TORRINGTON MFG. CO., THE, 50 Franklin St., Torrlngton, Conn........ 1252-1253 TRADE-WIND MOTORFANS, INC., 5725 So. Main St., Los Angeles 37, Calif. 1254 TRANE CO., THE, 2021 Cameron Ave., LaCrosse, Wis.............................. 1168-1169 TRION, INC., 1000 Island Ave., McKees Rocks, Pa.............................................. 1202 TUBE TURNS, INC., Louisville 1, Ky........................................................................ 1298 TUTTLE & BAILEY, INC., New Britain, Conn............................................. 1286-1287 U UNION ASBESTOS & RUBBER CO., 332 S. Michigan Ave., Chicago 4, 111. 1456-1457 UNITED STATES AIR CONDITIONING CORP., 3321 Como Avenue, S.E., Minneapolis 14, Minn................ '............................................................................. 1116 UNITED STATES RADIATOR CORP., Detroit 31, Mich.......................... 1344-1345 UNITED STATES REGISTER CO., Battle Creek, Mich........................... 1288-1289 UNITED STATES STEEL, Pittsburgh, Pa............................................................... 1292 UNITED STATES TESTING CO., INC., 1415 Park Ave., Hoboken, N. J... 1485 UNIVERSAL DIFFUSER CORP., 890 Whittier St., New York 59, N. Y.......... 1290 UTILITY APPLIANCE CORP., 4851 S. Alameda St., Los Angeles 58, Calif... 1140 V VAPOR HEATING CORP., 1450 Railway Exchange, Chicago 14, 111................ 1369 VINCO CO., INC., THE, 47 West 63rd St., New York 23, N. Y............. 1370-1371 VORTOX CO., Claremont, Calif................................................................................... 1203 VULCAN RADIATOR CO., THE, 22 Francis Ave., Hartford 6, Conn.............. 1224 W WAGNER ELECTRIC CORP., 6464 Plymouth Ave., St. Louis 14, Mo............... WALKER MFG. & SALES CORP., 1701-10 Penn St., St. Joseph, Mo........... WATER COOLING EQUIPMENT CO., New Hampshire Ave. and Weber Rd., 1257 1327 WATERMAN-WATERBURY CO., THE, 1121 Jackson St., N. E., Minneapolis TTAXUUill YT&DOIAA 06 VHUIUCU J............................ IHH-IWO-IWT-ITW-ITII WEBSTER ENGINEERING CO., THE, DIV. of SURFACE COMBUSTION CORP., 115 S. Frisco St., P. O. Box 2168, Tulsa, Okla.................................. 1379 WEIL-McLAIN CO., 641 W. Lake St., Chicago 6, 111............................................. 1351 WESTERN BLOWER CO., 1800 Airport Way, Seattle 4, Wash.......................... 1255 WESTERN ENGINEERING & MFG. CO., 4112 Ocean Park Ave., Venice, Calif................................................................................................................................ 1262 WESTINGHOUSE ELECTRIC CORP., Air Conditioning Div., Hyde Park, Boston 36, Mass.......................................................................................................... 1117 WESTINGHOUSE ELECTRIC CORP., STURTEVANT DIV., Hyde Park, DUalUU OU, .............................................................................................................................................................. ... ifcVTf . xww WILLIAMS OIL-O-MATIC DIV., EUREKA WILLIAMS CORP., Bloomington, 111.................................................................................................................... 1393 WILSON & CO., INC., Air Filter Div., 4100 S. Ashland Ave., Chicago 9, HI. 1205 GRANT WILSON, INC., 141 W. Jackson Blvd., Chicago 4, HI........................... 1452 L. J. WING MFG. CO., 59 Vreeland Mills Road, Linden, N. J. .. 1170-1171-1172 WOOD CONVERSION CO., Dept. 220-2, First National Bank Bldg., St. Paul . 1, Minn.......................................................................................................................... 1479 WORTHINGTON PUMP & MACHINERY CORP., Air Conditioning & Re frigeration Div., Harrison, N. J............................................................................. 1118 Y YARNALL-WARING CO., 133 Mermaid Ave., Philadelphia 18, Pa.................... YORK CORP., York, Pa.................................................................................................. YORK-SHIPLEY, INC., York, Pa................................................................................ YOUNG RADIATOR CO., Dept. 541, Racine, Wis................................................. YOUNG REGULATOR CO., 5209 Euclid Ave., Cleveland 3, Ohio....... ............ 1442 1119 1394 1173 1291 Z Z-CRETE DIVISION, ZONOLITE CO., 135 S. LaSalle St., Chicago 3, HI.. . 1458 JOHN ZINK CO., 4401 S. Peoria, Tulsa, Okla.............................................. 1380-1381 INDEX TO MODERN EQUIPMENT Of Advertisers Appearing In . Heating Ventilating Air Conditioning Guide, 1952 ACCUMULATORS . Westinghouse Electric Carp., Air John J. Nesbitt, Inc., 1166 McQuay, Inc., 1158-1159 Conditioning Div., 1117 Niagara Blower Co., 1112 Worthington Pump A Machinery Worthington Pump A Machinery Parks-Cramer Co., 1114-1115 Corp., 1H8 Corp., 1118 Patterson-Kelley Co., Inc- The York Corp., 1119 1221 ADSORBERS, Odor Young Radiator Co., 1173 Petroleum Heat A Power Co^ 1388 American Solvent Reoovery Corp., 1389 " 1180-1187 W. B. Connor Engineering Corp., 1188-1191. 1270-1271 AIR CLEANING EQUIPMENT (See also Filters, Air) Air A Refrigeration Corp., 1099 ` Air Devices, Inc., 1178, 1263 Air Filter COrp., 1177 Air-Maze Corp., The, 1180-1182 American Air Filter Co., Ine., 1183-- 1185 American Moistening Co., 1214 American Radiator A Standard Sanitary Corp.; 1328-1331 American Solvent Recovery Corp.. 1186-1187 Y. D. Anderson Co., The, 1410-1411 AIR CONDITIONING COM PRESSION EQUIPMENT Airtemp Div., Chrysler Corp., 1126-- 1127 Baker Refrigeration Corp., 1225 Carrier Corp., 1106-1107 Curtis Refrigerating Div., of Curtis Mfg. Co., 1227 Frick Co., 1228 - Frigidaire, Div. of General Motors, 1110 General Electric Co., 1108-1109 Mills Industries,. Inc.,, 1230 Heady Power Co., The, 1231 Trane Co., The, 1168-1169 Westinghouse Electric Corp., Air Conditioning Div., 1117 Worthington Pump A Machinery Ready Power Co., The, 1231 Refrigeration Appliances, Ino,, 1232 Refrigeration Economics Co., Ino,, 1167 Refrigeration Engineering, Inc., 1233 Seivd, Inc., 1137 Trane Co., The, 1168-1169 United States Air Conditioning Corp., 1116 Waterm&n-Waterbury Co., The, 1138-1139 Western Blower Co., 1255 Westinghouse Electrio Corp., Air Conditioning Div., 1117 Worthington Pump A Machinery Corp., 1118 York Corp., 1119 Young Radiator Co., 1173 Continental Air Filters, Inc., 1192 ..Corp., 1118 Dollinger Corp. (formerly Staynew York Corp., 1119 AIR COOLING EQUIPMENT Filter Corp.), 1194-1195 (See Cooling Equipment, Air) Farr Co., 1198-1197 Glasfloes, 1193 Owens-Coming Fiberglas Corp., 1198 Parka-Cramer Co., 1114-1115 Research Products Corp., 1199 AIR CONDITIONING CON TROLS (See Controllers and Con trol Equipment, Humidity and Temperature Controls) AIR COOLING, HUMIDIFYING AND DEHUMIDIFYING AP PARATUS Aerofin Corp., 1217-1219 H. J. Somers, Inc., 1200-1201 Air A Refrigeration Corp., 1099 ' Trion, Inc., 1202 Vortox Co., 1203 AIR CONDITIONING REGIS Airtemp Div., Chrysler Corp., 1126 TERS AND GRILLS (See Grilles, 1127 Westinghouse Electric Corp., Stur- Registers) American Blower Corp., 1100-1101 tevant Div., 1204, 1256 American Moistening Co., 1214 Wilson A Co., Inc., 1205 AIR COMPRESSORS (See Com pressors, Air) AIR CONDITIONING SCREEN (See Shade Screening) AIR CONDITIONING UNITS American Radiator A Standard Sanitary Corp., 1328-1331 Armstrong Machine Works, 1412 1413 Bahnson Co., The, 1102-1103 Acme Industries, Inc., 1216 Baker Refrigeration Corp., 1225 AIR CONDITIONING. Absorp Air A Refrigeration Corp., J"" Bayiey Blower Co., 1236 - tion Type, Oil and Gas Fired Airtemp Div., Chrysler Corp., 1126- Buensod-Stacey, Inc., 1104 Servel, Inc., 1137 1127 Buffalo Forge Co., 1238 American Blower Corp., 1100-1101 Carrier Coip., 1106-1107 American Radiator A Standard Clarage Fan Co., 1105 AIR CONDITIONING COILS Sanitary Corp., 1328-1331 Farr Co., 1196-1197 Acme Industries, Inc., 1216 Bahnson Co., The, 1102-1103 Fedders-Quigan Corp., 1153 Aerofin Corp., 1217-1219 Baker Refrigeration Corp., 1225 Frick Co., 1228 American Blower Corp., 1100-1101 Bell A Gossett Co., 1396-1397 General Electric Co., 1108-1109 Baker Refrigeration Corp., 1225 Bishop. A Babcock Mfg. Co., The, Jenn-Air Products Co., 1245 : Bell A Gossett Co., 1396-1397 _(_M_a__s_s_a_c_h_u_s_e_tts Blower Div.), 1237 Kennard Corp., 1157 Carrier Corp., 1106-1107 Buensod-Stacey, Inc., 1104 Mario Coil Co., 1229 Frigidaire, Div. of General Motors, Buffalo Forge Co., 1238 McQuay, Inc., 1158-1159 1110 Carrier Corp., 1106-1107 Modine Mfg. Co., 1160-1161 Hastmgs Air Conditioning Co., Ine., Clarage Fan Co., 1105 D. J. Murray Mfg. Co.. 1163 _ Curtis Refrigerating Machine,DiJvo.hn J. Nesbitt, Inc., 1166 gennard Corp., 1157 , of Curtis Mfg. Co., 1227 Niagara Blower Co., 1112 Mario Cod Co., 1229 Farr Co., 1196-1197 Parks-Cramer Co., 1114-1115 rJSXor<^ Corp., 1162 Fedders-Quigan Corp., 1153 Ready Power Co., The, 1231 McQuay Inc., 1158-1159 Frick Co., 1228 Refrigeration Appliances, Inc., 1232 Modine Mfg. Co., 1160--1161 Frigidaire, Div. of-General Motors, Refrigeration Economics Co., Inc., John J. Nesbitt, Inc., 1166 1110 1167 Niagara Blower Co.. 1112 General Electric Co., 1108-1109 Refrigeration Engineering Inc., 1233 Refrigeration Appliances, Ine., 1232 Hastings Air Conditioning Co., Inc. Trane Co., The, 1168-1169 Refrigeration Economics Co.,Inc., 1111 United States Air Conditioning. r. . Jenn-Air Products Co., 1245 Corp., 1116 Refrigeration Engineering, Inc., 1233 8. T. Johnson Co., 1386-1387 Utility Appliance Corp., 1140 Home-Turner Radiator Co., The, Kennard Corp., 1157 -ri223 ~ Mario Cod Co., 1229 Westinghouse Electric Corp., Air Conditioning Div., 1117 Co., The. 1168-1169 McQuay, Inc.. 1158-1159 Worthington Pump A Machinery States Air Conditioning Meyer Furnace Co.. The, 1130-1131 Corp., 1118 Corp., 1116 . L. J. Mueller Furnace Co., 1132-- York Corp., 1119 Vulcan Radiator Co., The, 1224 1133 Young Radiator Co., 1173 Numerals following Manufacturers' Names refer to pages in the Catalog Data Section 1073 1074 1952 Guide AIR. DIFFUSERS AND VENTI AIR TRAPS (See Trope, Air) AXIAL FLOW FANS (See Fane, LATORS, CEILING, FLOOR Axial Flow) AND WALL AIR TUBING, Flexible Metal Air Control Products, Inc., 1264 (See Tubing, Flexible Metallic) BASEBOARD HEATING 1265 American Radiator A Standard Air Devices, Inc., 1178, 1263 AIR VELOCITY METERS (See Sanitary Corp., 1328-1331 AlftAdin Heating Carp., 1234 Meters) Brown Products Co., 1333 - Anemoetat Corp. of America, .1266 Burnham Corp., 1335 1267 AIR WASHERS Campbell Heating Co., 1124-1125, Barber-Colman Co., 1269 Air A Refrigeration Corp., 1099 1142 W. B. Connor Engineering Carp., American Blower Corp., 1100-1101 Crane Co., 1336-1337 1188-1191, 1270-1271 Bahnson Co.. The, 1102-1103 . C. A. Dunham Co., 1415-1419 Charles Demuth A Sons, Inc., 1272 Bayley Blower Co., 1236 Fedders-Quigan Corn., 1153 Hart A Cooley Mfg. Co., 1274-1275 Bishop A Babcock Mfg. Co., The, General Automatic Products Corp., Independent Register Co., The, (Massachusetts Blower Div.), 1237 1338 1278 Jenn-Air Products Co., 1245 Minneapolis-Honeywell Regulator Co., 1316-1317 Pyle-National Co., The, Multi-Vent - *Div, 1280-1281 A Grille Mfg. Co., Ino, Buensod-Staoey, Inc., 1104 Buffalo Forge Co., 1238 Carrier Corp., 1106-1107 Clarage Fan Co., 1105 Continental Air Filters, Inc., 1192 Mario Coil Co., 1229 D. J. Murray Mfg. Co., 1163 Kritxer Radiant Coils, Inc., 1222 National Radiator Co., The, 1340 1341 Roxne-Turney Radiator Co., The, 1223 United States Radiator Corp., 1344 1345 1279 ,. Standard Stamping A Perforating Co., 1282 Titus Mfg. Corp., 1284-1285 Tuttle A Bailey, Inc., 1286-1287 United States Register Co., -1288 1289 . Universal Diffuser Corp., .1290 New York Blower Co., The, 1250 Niagara Blower Co., 1112 Parks-Cramer Co., 1114-1115 . Trane Co.. The. 1168-1169 Western Blower Co., 1255 Westinghouse Electric Corp., Stur- tevant Div., 1204, 1256 York Corp., 1119 Vulcan Radiator Co., The, 1224' Warren Webster A Co., 1437-1441 Weil-McLain Co., 1351 . BELLOWS Chicago Metal Hose Div., Flexonics Corp., 1176 ,, Fulton Sylphon Div., The, Robert- ahaw-Fulton Controls Co., 1304 AIR DUCTS (See Ducts) ALARMS, Water Level 1305 McDonnell A Miller, Inc., 1372-1375 AIR ELIMINATORS V. D. Anderson Co., The, 1410-1411 C. A. Dunham Co., 1415-1419 Illinois Engineering Co., 1424-1425 Jas. P. Marsh Corp., 1428-1429 Sarco Co., Inc., 1438-1435 Photoswitch, Inc., (Affiliate of Com bustion Control Corp.), 1301 Yamall-Waring Co., 1442 ALUMINUM DUCTS (See Ducts, Aluminum) BENDS, Pipe, Ferrous and Non- Ferrous Grinnell Co., IncA 1154-1155 Arthur Harris A Co., 1295 LadishCo, 1296 Parks-Cramer Co., 1114-1115 .....................,,, . ALUMINUM FOIL, Insulation AIR FILTER GAGE . Infra Insulation, Inc., 1482 Air Devices, Inc^ 1178, 1263 Lockport Cotton Batting Co., 1474 Owens-Coming Fiberglas Corp., Reflectal Corp., 1483 1198 Research Products Corp., 1199 Silvercote Products, Inc., 1484 ALUMINUM FOIL VAPOR AIR FILTERS (See Filters, Air; BARRIER (See Aluminum Foil) Air Cleaning Equipment) AIR MEASURING INDICAT ING AND RECORDING IN STRUMENTS . Anemoetat Corp. of America, 1286 1267 . Laboratories, Inc., ALUMINUM SHEETS (See Sheets, Aluminum) AMMONIA COILS Ammonia) ANCHORS pjpe (See Coils, Minneapolis-Honeywell Regulator Co.. 1316-1317 Parks-Cramer Co., 1114--1115 Powers Regulator Co., Tbe.1321 Taylor Instrument Co's., 1326 H. W. Porter & Co., Ino., 14 ANEMOMETERS Illinois Testing Laboratories, Ino, 1311 BENDS (See Pipe, Returns) BLOCKS, Asbestos . Philip Carey Mfg. Co., The, 1448 1449 Union Asbestos A Rubber Co., 1456-1457 Grant Wilson, Inc., 1452 BLOCKS, Glass American Structural Products Co., 1460 Pittsburgh Corning Corp., 1462-1463 BLOWER HOUSINGS Bishop A Babcock Mfg. Co., The, (Massachusetts Blower Div.), 1237 Champion Blower A Forge Co., 1239 Lau Blower Co., The, 1248 Meyer Furnace Co., 1130-1131 Westinghouse Electric Corp-, Stur- tevant Div., 1204, 1256 AIR MOISTENING APPARA TUS (See Humidifiers) AIR PURIFYING APPARATUS Air A Refrigeration Corp., 1099 Air Filter Corp., 1177 _. American Solvent Recovery Corp., 1186-1187 V. D. Anderson Co., The, 1410-1411 W. B. Connor Engineering Corp., 1188-1191, 1270-1271 J. F. Pritchard A Co. (Puridryer Dept.), 1212 H. I. Somers, Inc., 1200-1201 Trion, Inc., 1202 Universal Diffuser Corp., 1290 Wilson A Co., Ino., 1205 AIR RECEIVERS (See Receivers, Air) AIR RECOVERY, Method of Axnflriftan Solvent Recovery Corp., 1186-1187 .^ W. B. Connor Engineering Corp., 1188-1191, 1270-1271 ASBESTOS PRODUCTS (See In sulation) Philip Carey Mfg. Co., The, 1448 1449 Johns-Manvffie, 1470-1471 H. W. Porter A Co.. Ino., 1454 Union Asbestos A Rubber Co., 1456-1457 Grant Wilson, Inc., 1452 AT__M__OSPHERIC COOLING TOW----E--R---S----(-See Cooling Towers, Atmospheric) ATOMIZING SPRAY NOZZLES (See Spray Nozzles) ATTIC FAN COOLERS (See Fane, Attic; Ventilators, Attic) AUTOMATIC FUEL BURNING EQUIPMENT (See Burners, Au tomatic: Gae Burners,* OH Burners; Stokers) AUTOMATIC SHUTTERS (See Shutters, Automatic) BLOWER MOTORS (See Motors, Electric) BLOWERS, Centrifugal (See Fans) BLOWERS, Fan (See Fans, Supply and Exhaust) . BLOWERS, Forced Draft Aladdin Heating Corp., 1234 American Blower Corp., 1100-1101 Bayley Blower Co., 1236 Bishop A Babcock Mfg. Co., The, (Massachusetts Blower Div.), 1237 Buffalo Forge Co., 1238 Champion Blower A Forge Co., 1239 Clarage Fan Co., 1105 General Blower Co., 1241 Ilg Electric Ventilating Co., 1156, 1244 Joy Mfg. Co.. 1246-1247 Herman Nelson Div., American Air Filter Co.. Ino., 1164-1165 New York Blower Co., The, 1250 United States Air Conditioning Corp, 1116 Please mention THE GUIDE 1952 when writing to Advertisers Index to Modem Equipment 1075 Westinghouse Electrio Corp, Stur- United States Aire Conditioning BOILERS, Gaa Fired tevant Div., 1204,1256 Corp, 1116 Airtemp Div, Chrysler Corp, 1126 L. J. Wing Mfg. Co, 1170-1172 Utility Applicance Corp,1140 1127 . L. J. Wing Mfg. Co, 1170-1172 Aldrich Co, 1332 BLOWERS, Heating and Venti lating BOILER-BURNER Aladdin Heating Corp, 1234 Air Devices, Ine, 1178, 1263 American Blower Corp, 1100-1101 Aldrich Co, 1332 American Foundry A Furnace Co, American Radiator A Standard 1120-1121 Sanitary Corp., 1328-1331 American Radiator A Standard Bryan Steam Corp, 1334 Sanitary Corp, 1328-1331 Burnham Corp, 1335 Automatic Gas Equipment Co, Fitsgibbons Boiler Co, Inc, 1360 1151 1301 Bayley Blower Co, 1236 General Automatic Products Corp, Bishop A Babcock Mfg. Co, The, 1338 (Massachusetts Blower Div.), 1237 General Electric Co, 1108-1109 Buffalo Forge Co, 1238 Hook A Ackerman, Inc, 1339 Campbell Heating Co, 1124-1125, L. J. Mueller Furnace Co, 1132-1133 1142 . National Radiator Co, The, 1340 E. K. Campbell Co, 1143 1341 Champion Blower A Forge Co, 1239 Norge-Heat, Div. of Borg-Wamer Clarage Fan Co, 1105 Corp, 1134-1135 C. A. Dunham Co, 1415-1419 Pacific Steel Boiler Div, U. S. General Blower Co., 1241 Radiator Corp, 1342-1343 Hartsell Propeller Fan Co, Div. of Petroleum Heat A Power Co, 1388 Castle Hills Corp, 1242 1389 Hastings Air Conditioning Co., Inc, Ray Oil Burner Co, 1390-1391 1111 H. B. Smith Co, Inc, The, 1350 Dg Electric Ventilating Co, 1156, Sonner Burner Co, 1378 1244 United States Radiator Corp, 1344 Jenn-Air Products Co, 1245 1345 Joy Mfg. Co, 1246-1247 Weil-McLain Co, 1351 Lau Blower Co, The, 1248 Williams Oil-O-Matic Div., Eureka Meyer Furnace Co, The, 1130-1131 Williams Corp, 1393 Morrison Products, Inc, 1249 John Zink Co, 1380-1381 L J. Mueller Furnace Co, 1133-1133 ' Herman Nelson Div, American BOILER COMPOUNDS (See Air Filter Co, Inc, 1164-1165 . New York Blower Co, The, 1250 Compounds, Boiler) * Niagara Blower Co, 1112 BOILER COVERING (See Cover Refrigeration Appliances, Inc., 1232 Torrington Mfg. Co, The, 1252-1253 ing, Pipe and Surfaces) American Radiator A Standard Sanitary Carp, 1328-1331 Bryan Steam Corp, 1334 Burnham Corp, 1335 Cleaver-Brooks Co, 1353 Combustion Engineering - Super* heater. Inc, 1354-1355 Crane Co, 1336-1337 Cyclotherm Corp, 1354-1355 Dewey-Shepard Boiler Co, 1357 Dutton Boilers, Division HapmanDutton Co, 1358 Farrar A Trefts; Inc, 1359 Fitsgibbons Boiler Co, Inc., 1360 1361 General Electric Co, 1108-1109 Hook A Ackerman, Inc, 1339 International Boiler Works Co, The, 1362 Johnston Bros, Inc, 1363 Kewanee Boiler Corp, 1364-1367 L. J. Mueller Furnace Co, 1132-1133 National Radiator Co, The, 1340 1341 Norge Heat, Div. of Borg-Wamer Corp, 1134-1135 Pacifio Steel Boiler Div, U. S. Ra diator Corp, 1342-1343 Frank Prox Co, Inc., 1346 Spencer Heater, Lyooming-Spenoer Div, Avco Mfg. Corp, 1348-1349 Titusville Iron Works Co, The, (Div. of Struthers-Wells Corp.), 1363 United States Radiator Cop, 1344 1345 Vapor Heating Corp, 1369 Weil-McLain Co, 1351 Trade-Wind Motorfans, Inc, 1254 Trane Co, The, 1168-1169 .United States Air Conditioning Corp, 1116 Utility Appliance Corp, 1140 Western Blower Co., 1255 Westinghouse Electric Corp, Stur- tevant Div., 1204, 1256 L. J. Wing Mfg. Co, 1170-1172 . BOILER FEED PUMPS (See Pumps, Boiler Feed) BOILER FEEDERS (See Feeders, Boiler) BOILER GRATES (See Grates or Boilers) BOILERS, Heating - Airtemp Div, Chrysler Corp, 1126 1127 Aldrich Co, 1332 American Radiator A Standard Sanitary Corp, 1328-1331 Babcock A Wilcox Co, The, 1352 Brown Products Co, 1333 Bryan Steam Corp, 1334 BLOWERS, Pressure American Blower Corp, 1100-1101 Bayley Blower Co, 1236 BOILER WATER FIELD KIT for Testing and Treating Vinco Co, Inc, The, 1370-1371 Burnham Corp, 1335 Cleaver Brooks Co, 1353 . Combustion Engineering - Super heater, Inc, 1354^1355 . Buffalo Forge Co, 1238 Crane Co, 1336-1337 Champion Blower A Forge Co, 1239 BOILER WATER TREATMENT Cyclotherm Corp, 1356 . General Blower Co, 1241 Vinco Co, Inc, The, 1370-1371 Dewey-Shepard Boiler Co, 1357 Hartzell Propeller Fan Co, Div. Dutton Boilers, Division Hapm&n- of Castle Hills Corp, 1242 BOILERS, Cast-Iron Dutton Co, 1358 Hg Electric Ventilating Co, 1156, Airtemp Div, Chrysler Corp, 1126 Farrar A Trefts, Inc, 1359 1244 1127 Fitsgibbons Boiler Co, Inc, 1360 Ingeraoll-Rand, 1404 American Radiator A Standard 1361 United States Air Conditioning Sanitary Corp, 1328-1331 General Electric Co, 1108-1109 Corp, 1116 Burnham Corp, 1335 Hook A Ackerman, Ino., 1339 Westinghouse Electric Corp, Stur- Crane Co, 1338-1337 . International Boiler Works Co, The, tevant Div., 1204, 1256 General Electric Co, 1108-1109 1362 L. J. Wing Mfg. Co, 1170-1172 Hook A Ackerman, 1339 * S. T. Johnson Co, 1386-1387 L. J. Mueller Furnace Co, 1132-1133 Johnston Bros., Inc, 1363 BLOWERS, Turbine Western Blower Co, 1255 L. J. Wing Mfg. Co, 1170-1172 National Radiator Co, The, 1340 Kewanee Boiler Corp, 1364-1367 1341 L. J. Mueller Furnace Co, 1132-1133 Norge Heat, Div. of Borg-Wamer National Radiator Co, The, 1340 Corp, 1134-1135 1341 Frank Prox Co-, Ino., 1346 Norge Heat, Div. of Borg-Wamer BLOWERS, Warm Air Furnace H. B. Smith Co, Ino., The, 1350 Corp, 1134-1135 Aladdin Heating Corp., 1234 Spencer Heater, Lyooming-Spencer Pacific Steel Boiler Div, U. S. Ra American Foundry A Furnace Co, Div, Avco Mfg. Corp, 1348-1349 diator Com, 1342-1343 1120-1121 . United States Radiator Corp, 1344 Petroleum Heat A Power Co, 1388 American Furnace Co, 1122 1345 1389 * American Radiator A Standard Weil-McLain Co, 1351 Frank Prox Co, Inc, 1346 Sanitary Corp, 1328-1331 Williams Oil-O-Matic Div, Eureka H. B. Smith Co, Inc., The, 1350 Bishop A Babcock Mfg. Co, The Williams Corp, 1393 Spencer Heater, Lycomlng-Spenoer (Massachusetts Blower Div.), 1237 Div, Avco Mfg. Corp, 1348-1349 Campbell Heating Co, 1124-1125, BOILERS, Down Draft 1142 Cleaver-Brooks Co, 1353 Titusville Iron Works Co, The (Div. of Struthers-Wells Carp.), Clarage Fan Co, 1105 Farrar A Trefts, Inc, 1359 1368 General Blower Co, 1241 Kewanee Boiler Corp, 1364-1367 United States Radiator Corp, 1344 Meyer Furnace Co, The, 1130-1131 Titusville Iron Works Co., The 1345 Morrison Products, Inc, 1249 (Div. of Strutheis-Wells Corp.), Vapor Heating Corp, 1369 ' L. J. Mueller Furnace Co, 1132-1133 1368 Weil-McLain Co, 1351 Numerals following Manufacturers* Names refer to pages In the Catalog Data Section 1G76 1952 Guide Williams Oil-O-Matic Div., Eureka Williams Oil-O-Matic Div., Eureka BURNERS, Gas (See Qae Burners) Williams Corp., 1393 Williams Corp., 1393 BURNERS, Oil (See OH Bumeer) BOILERS, Magazine Feed BOILERS, Unit Steam Gener- Farrar A Trefts, Ido., 1359 a tor CALKING, Building . Spencer Heater, Lycoming-Spencer Cleaver-BrookB Co., 1353 Philip Carey Mfg. Co., The, 1448 Div., Avco Mfg. Corp., 1348-1349 Combustion Engineering - Super 1449 beater, Inc., 1354-1355 BOILERS, Oil Burning Air Devices, Inc., 1178, 1263 Airtemp Div., Chrysler Corp., 1126-- 1127 Aldrich Co., 1332 American Radiator A Standard Cyclotherm Corp., 1356 Dutton Boilers, Division Hapmanr Dutton Co., 1358 International Boiler Works Co., The, 1362 Johnston Bros., Inc., 1363 CAPS, Vent Flue G. C. Breidert Co., The. 1258 CARBON* Activated American Solvent Recovery Corp., 1185-1187 Sanitary Corp., 1328-1331 Babcock A Wilcox Co., The, 1352 Brown Products Co., 1333 Bryan Steam Corp., 1334 Burnham Corp., 1335 Cleaver-Brooks Co., 1353 Titusville Iron Works Co., The, (Div. of Struthers-Wells Corp.), 1368 Vapor Heating Corp., 1369 _B_O__I_L_E__R__S,,, _W__a_t_e_r__T_u__b_e W. B. Connor Engineering Corp., 1188-1191, 1270-1271 CASTINGS, Bronze and Dairy Nickel Silver Metal Arthur Harris A Co., 1295 . Combustion Engineering - Super- American Radiator A Standard heater, Inc., 1354-1355 Sanitary Corp., 1328-1331 CELLULAR GLASS (See Glass, Crane Co., 1336-1337 Babcock A Wilcox Co., The, 1352 Cellular) Cyclotherm Corp., 1356 Dewey-Shepard Boiler Co., 1357 Dutton Boilers, Division Hapman- Dutton Co., 1358 Bryan Steam Corp., 1334 Combustion Engineering - Super heater, Inc., 1354-1355 Foster Wheeler Corp., 1209 CEMENT, Asbestos Philip Carey Mfg. Co., The, 1448 1449 Farrar & Trefts, Inc., 1359 ', Fitzgibbons Boiler Co., Inc., 1360 1361 General Electric Co. 1108-1109 International Boiler Works Co., The, 1362 S. T. Johnson Co., 1386-1387 Johnston Bros., Inc., 1363 Kewanee Boiler Corp., 1364-1367 National Radiator Co., The, 1340 International Boiler Works Co., The, 1362 CEMENT, Insulating H. B. Smith Co., Inc., The, 1350 Titusville Iron Works Co., The (Div. of Struthers-Wells Corp.), 1368 Philip Carey Mfg. Co., The, 1448 1449 Johns-Manville, 1470-1471 Owens-Corning Fiberglas Corp., 1451 BRACKETS. Radiator Union Asbestos A Rubber Co., American Radiator A Standard Sanitary Corp., 1328-1331 1456-1467 Z-Crete Div., Zonolite Co., 1458 1341 Carty. A Moore Engineering Co., Norge Heat, Div. of Borg-Wamer 1414 CEMENT, Mineral Wool C__o_r_p_., 1134-3135 Grinnell Co., Inc., 1154-1155 Philip Carey Mfg. Co., The, 1448 Pacific Steel Boiler Div., U. 8. Ra- National Radiator Co., The, 1340- 1449 diator Corp., 1342-1343 1341 . Petroleum Heat A Power Co.* 1388- United States Radiator Corp., 1344 CEMENT, Refractory (See Re 1389 1345 fractories) Frank Prox Co., Inc., 1346 ' H. B. Smith Co., Inc., The, 1350 BREECHINGS Spencer Heater, Lycoming-Spencer Farrar A Trefts, Inc., 1359 Div., Avco Mfg. Corp., 1348-1349 __ CHIMNEY TOPS G. C. Breidert Co.* The, 1258 Titusville Iron Works Co., The BURNER PROTECTION, Gas (Div. ofStruthers-Wells Corp.), andOil CHIMNEYS (See Breechings) 1388 ' Combustion Control Corp., 1301 United States Radiator Corp., 1344- Mercoid Corp., The, 1314 1345 Milwaukee Gas Specialty Co., 1315 Vapor Heating Corp., 1369 - Weil-McLain Co., 1351 BURNERS* Automatic Williams Oil-O-Matic Div., Eureka Ace Engineering Co., 1382 ' Williams Corp., 1393 Aldrich Co., 1332 Automatic Burner Corp., 1383 CIRCULATORS, Hot Water Heating ' Bell A Gossett Co.. 1396-1397 Chicago Pump Co.* 1403 . Crane Co., 1335-1337 Hoffman Specialty Co., 1420-1423 Jas. P. March Corp., 3428-1429 BOILERS, Steel Enterprise Engine A Machinery Minneapolis-Honeywell Regulator Airtemp Div., Chrysler Corp., 1126-- Co., Burner Div., Sub. of General Co., 1315-1317 1127 Metals Corp., 1384 National Radiator Co., The, 1340 Aldrich Co., 1332 8. T. Johnson Co., 1385-1387 1341 Bryan Steam Corp., 1334 Burnham Corp., 1335 . H. C. Little Burner Co,, 1385 Pacific Steel Boiler Div., U. S. Ra Petroleum Heat A Power Co., 1388- diator Corp., 1342-1343 Cleaver-Brooks Co., 1353 Combustion Engineering - Super heater, Inc., 1354-1355 Cyclotherm Corp., 1356 Dewey-Shepard Boiler Co., 1357 Ray Oil Burner Co., 1390-1391 C. L.-Bayfield Co., 1392 Sooner Burner Co., Inc., 1378 United States Radiator Corp.* 1344-- Taoo Heaters, Inc., 1400 H. A. Thrush A Co., 1398-1399 Trane Co., The, 1165-1169 United States Radiator Corp., 1344 1345 . Dutton Boilers, Division Hapman- 1345 Dutton Co., 1358 - Farrar A Trefts, Inc., 1359 Fitagibbons Boiler Co., Inc., 1360- Webster Engineering Co., The, 1379 BURNERS* Combination for CLEANERS, Air (See Air Cleaning Equipment) 1361 Foster Wheeler Corp., 1209 General Electric Co., 1108-1109 Natural and L.P. Gases L. J. Mueller Furnace Co., 1132-1133 COAL BURNERS Automatic) ' (See Burners, S. T. Johnson Co., 1385-1387 BURNERS* Combination Gaa Johnston Bros., Inc., 1363 Ke..wanee Boiler Cor^p.,. 1364-1367 National Radiator Co., The, 1340- 1341 Pacific Steel Boiler Div., U. S. Ra- and Oil Ace Engineering Co., 1382 Babcock A Wilcox Co., The, 1352 Cleaver-Brooks Co., 1353 Dewey-Shepard Boiler Co., 1357 COATINGS, Protective Philip Carey Mfg. Co., The, 1448 1449 Insul-Mastic Corp. of America, 1467 diator Corp., 1342-1343 Enterprise Engine A Machinery Co., Petroleum Heat A Power Co., 1388- Burner Div., Sub. of General COILS, Aluminum 1389 Metals Corp., 1384 Aerofin Corp., 1217-1219 Rheem Mfg. Co., 1136 S. T. Johnson Co., 1386-1387 Mario Coil Co., 1229 Spencer Heater, Lycoming-Spencer Petroleum Heat A Power Co., 1388- McQuay, Inc., 1158-1159 Div.. Avco Mfg. Corp., 1348-1349 1389 John J. Nesbitt, Inc., 1166 Titusville Iron Works Co., The Ray Oil Burner Co., 1390-1391 Niagara Blower Co., 1112 (Div. of Struther8-Wells Corp.), C. L. Rayfield Co., 1392 Patterson-Kelley Co., Inc.* The* 1368 . Webster Engineering Co., The, 1379 1221 Please mention THE GUIDE 1952 when writing to Advertisers Index to Modem Equipment 1077 Refrigeration Appliances* Inc., 1232 Refrigeration Appliances* Inc., 1232 Nash Engineering Co.* 1405-1407 Refrigeration Economics Co., Inc., Refrigeration Economics Co., Inc~ Worthington Pump and Machinery 1167 1167 Corp., 1118 Refrigeration Engineering, Inc., Refrigeration Engineering, Inc.* 1233 Rome-Tumey Radiator Co., The, 1223 Trane Co., The, 1168-1169 Worthington Pump A Machinery Corp-, 1H8 . Young Radiator Co., 1173 COILS, Ammonia Acme Industries, Inc., 1216 Aerofin Corp., 1217-1219 . GAO Manufacturing Co.* The, 1220 1233 Rome-Tumey Radiator Co., The, 1223 Trane Co., The, 1168-1169 United States Air Conditioning Corp., 1116 Westinghouse Electric Corp., Air Conditioning Div., 1117 Worthington Pump A Machinery Corp., 1118 York Corp., 1119 Young Radiator Co., 1173 COMPRESSORS* Refrigeration Airtemp Div., Chrysler Corn., 1126 1127 Baker Refrigeration Corp., 1225 Carrier Corp., 1106-1107 Curtis Refrigerating Machine Div. of Curtis Mfg. Co., 1227 Frick Co.. 1228 Frigidaire, Div. of General Motors, 1110 General Electric Co., 1108-1109 Ingersoll-Rand, 1404 Kennard Corp., 1157 Mills Industries, Inc., 1230 Mario Coil Co., 1229 COILS, Pipe, Copper Ready Power Co., The, 1231 McQuay, Inc., 1158-1159 Arthur Harris A Co., 1295 Trane Co., The. 1168-1169 . Modine Mfg. Co., 1160-1161 Kritzer Radiant Coils, Inc., 1222 Westinghouse Electric Corp., Air Niagara Blower Co., 1112 - Niagara Blower Co., 1112 Conditioning Div., 1117 Patterson-Kelley Co., Inc., . The, Refrigeration Engineering, Inc., Worthington Pump A Machinery 1221 1233 Corp., 1118 Refrigeration Appliances, Inc., 1232 York Carp., 1119 York Corp., 1119 Refrigeration Economics Co., Inc., 1167 Refrigeration Engineering, Inc., 1233 Trane Co., The, 1168-1169 Worthington Pump A Machinery Corp., 1118 . Yaroall-Waring Co., 1442 York Corp., 1119 COILS, Pipe, Iron Acme Industries, Inc., 1216 Bayley Blower Co., 1236 Kritzer Radiant Coils, Inc., 1222 Niagara Blower Co., 1112 Refrigeration Engineering, Inc., CONCRETE INSERTS (Sea In serts, Concrete) CONDENSERS and EVAPORA TORS Acme Industries, Inc., 1216 American Blower Corp., 1100-1101 Baker Refrigeration Corp., 1225 COILS* Pipe and Tube* Non* COILS* Blast Ferrous ' Aerofin Corp., 1217-1219 . McQuay, Inc., 1158-1159 American Blower Corp., 1100-1101 Niagara Blower Co., 1112 Bayley Blower Co., 1236 Patterson A Kelley Co., Inc., The, GAO Mfg. Co., The, 1220 1221 ' Hastings Air Conditioning Co., Inc., Refrigeration Engineering, Inc., 1111 1233 Kennard Corp., 1157 Rome-Turney Radiator Co., The, Mario Coil Co., 1229 * 1223 McCord Corp., 1162 McQuay, Inc., 1158-1159 Modine Mfg. Co.* 1160-1161 D. J. Murray Mfg. Co., 1163 John J. Nesbitt, Inc., 1166 New York Blower Co., The, 1250 Niagara Blower Co., 1112 Refrigeration Appliances, Inc.* 1232 Refrigeration Economies Co., Inc., 1167 COILS* Stainless Steel Arthur Harris A Co., 1295 Mario Coil Co., 1229 McQuay, Inc., 1158-1159 Niagara Blower Co., 1112 Patterson-Kelley Co., Inc., 1221 Trane Co., The, 1168-1169 . The, Rome-Tumey Radiator Co., The, 1223 COILS. Tank Trane Co., The, 1168-1169 Bell A Gossett Co., 1396-1397 United States Air Conditioning Patterson-Kelley Co., Inc., The, Corp., 1116 1221 Vulcan Radiator Co., The, 1224 Taco Heaterc, Inc., 1400 Westinghouse Electric Corp., Stur- Western Blower Co., 1255 tevant Div., 1204, 1256 Young Radiator Co., 1173 COLLECTORS, Fly Ash Baltimore Aircoil Co., Inc., 1226 Bell A Gossett Co., 1395-1397 Buffalo Forge Co., 1238 Carrier Corp., 1105-1107 Curtis Refrigerating Machine Div. of Curtis Mfg. Co., 1227 Farrar A Trefts, Inc., 1359 Foster Wheeler Corp., 1209 Frick Co., 1228 Frigidaire, Div. of General Motors, 1110 GAO Mfg. Co.. The, 1220 Arthur Harris A Co., 1295 Kennard Corp., 1157 Mario Coil Co., 1229 McQuay, Inc., 1158-1159 Niagara Blower Co., 1112 Ready Power Co., The, 1231 Refrigeration Appliances, Inc., 1232 Refrigeration Economics Co., Inc., 1167 , Refrigeration Engineering, Inc., 1233 Rome-Turney Radiator Co., The, 1223 Trane Co., The* 1158-1169 United States Air Conditioning Corp., 1116 Westinghouse Electric Corp., Air American Blower Corp., 1100-1101 Conditioning Div^ 1117 COILS, Brass V. D. Anderson Co., The, 1410-1411 Worthington Pump A Machinery Arthur Harris A Co., 1295 . Corp., 1118 Mario Coil Co., 1229 COMPOUNDS* Boiler York Corp., 1119 McQuay, Inc., 1158-1159 Vinco Co., Inc., The, 1370-1371 Young Radiator Co., 1173 Trane Co., The, 1168-1169 COILS, Cooling Aerofin Corp., 1217-1219 COMPOUNDS* Boiler and Radi* CONDUIT* Refrigeration (See ator Sealing Hose, Flexible Metal, and Liquid, Vinco Co., Inc., The, 1370-3371 Gas, Vapor) American Blower Corp., 1100-1101 Frick Co., 1228 . COMPOUNDS, Soot Destroyer CONDUITS, Underground Fit Frigidaire, Div. of General Motors. Vinco Co., Inc.. The, 1370-1371 tings 1110 Durant Insulated Pipe Co., 1453 GAO Mfg. Co., The, 1220 Arthur Harris A Co., 1295 Hastings Air Conditioning Co., Inc.. COMPRESSOR MOTORS Motors, Electric) (See H. W. Porter A Co., Inc., 1454 Ric-wiL Co., The, 1455 1111 Kennard Corp., 1157 Mario Coil Co., 1229 CONDUITS. Underground Pipe COMPRESSOR TUBING, Flex Durant Insulated Pipe Co., 1453 ible (See Tubing, Flexible Metallic). H. W. Porter A Co., Inc., 1454 McCord Corp., 1162 Rio-wiL Co., The, 1455 . McQuay, Inc., 1158-1159 Modine Mfg. Co.* 1160-1161 D. J. Murray Mfg. Co., 1163 John J. Nesbitt, Inc., 1166 New York Blower Co., The, 1250 Niagara Blower Co., 1112 Patterson-Kelley 1221 Co., . Inc;, The, COMPRESSORS* Air Curtis Refrigerating Machine Div. of Curtis Mfg. Co., 1227 IngersoU-Rand, 1404 Johnson Service Co., 1312-1313 Joy Mfg. Co., 1240-1247 Minneapolis-Honeywell Regulator Co,, 1310-1317 Z Crete Div., Zonolite Co., 1458 CONTROL, Air Volume Damper Air Control Products* Inc.* 1264 1265 Air Devices, Inc., 1178, 1263 Anemostat Corp. cl America* 1266 1267 Numerals following Manufacturers* Names refer to pages In the Catalog Data Section 1078 1952 Guide Barber-Colman Co., 1269 . Warren Webster & Co., 1437-1441 Ready Power Co., The, 1231 Johnson Service Co., 1312-1313 Young Radiator Co., 1173 Refrigeration Economics Co., Inc., Minneapolis-Honeywell Regulator 1167 Co., 1316-1317 Powers Regulator Co., The, 1321 Young Regulator Co., 1291. CONTROL, Boiler Water Level McDonnell A Miller, Inc., 1372 1375 CONVECTORS A CONVEC TOR ENCLOSURES Acme .Industries, Inc., 1216 Airtherm Mfg. Co., 1141 American Radiator A Standard Sanitary Corp., 1328-1331 Brown Products Co., 1333 Refrigeration Engineering, Inc., 1233 Servel, Inc., 1137 Trane Co., The, 1168-^1169 Worthington Pump A Machinery Corp., 1118 Young Radiator Co., 1173 Mercoid Corp., The, 1314 Crane Co., 1336-1337 Penn Controls, Inc., 1319 Sarco Co., Inc., 1434-1435 Warren Webstar A Co., 1437-1441 CONTROL EQUIPMENT, Com bustion Combustion Control Corp., 1301 Detroit Regulator Co., 1302 General Controls, 1306-1307 Illinois Engineering Co., 1424-1425 Mercoid Corp., The, 1314 Minneapolis-Honeywell Regulator Co., 1316-1317 National Radiator Co., The, 1340 1341 Penn Controls, Inc., 1319 Perfex Corporation, 1320 Simplex Mfg. Co., 1323 - C. A. Dunham Co., 1419-1419 Fedders-Quigan Corp., 1153 GAO Mfg. Co., The, 1220 Kritxer Radiant Coils, Inc., 1222 Modine Mfg. Co., 1160-1161 National Radiator Co., The, 1340 1341 John J. Nesbitt, Inc., 1166 Rome-Turney Radiator Co., The, 1223 Shaw-Perkins Mfg. Co., 1347 H. J. Somers. Inc., 1200-1201 Trane Co., The, 1168-1169 Tuttle A Bailey, Inc., 1286-1287 United States Radiator Corp., 1344 1345 Warren Webster A Co.. 1437-1441 Young Radiator Co., 1173 COOLING EQUIPMENT, Water (See also Water Cooling) Acme Industries, Inc., 1216 Aerofin Corp., 1217-1219 Airtemp Div., Chrysler Corp., 1126 1127 Baker Refrigeration Corp., 1225 Baltimore Airooil Co., Inc., 1226 Bell A Gossett Co., 1396-1397 Binks Mfg. Co., 1206-1207 , Carrier Corp.., 1106-1107 "" Fedders-Quigan Corp., 1153 Fluor Corp., Ltd., The, 1208 Foster Wheeler Corp., 1209 Frick Co., 1228 Frigidaire, Div. of General Motors, 1110 General Electric Co., 1108-1109 United States Radiator Corp., 1344 Hastings Air Conditioning Co., Inc., 1345 COOLING EQUIPMENT. Air 1111 Webster Engineering Co., The, 1379 Aerofin Corp., 1217-1219 Kennard Corp., 1157 Airtemp Div., Chrysler Corp., 1120- Lilie-Hoffmann Cooling Towers, CONTROL EQUIPMENT, Time April Showers, Inc., 1459 Barber-Colman Co., 1269 General Controls, 1306-1307 Minneapolis-Honeywell Regulator Co., 1316-1317 Penn Controls, Inc., 1319 Perfex Corp., 1320 American Blower Corp., 1100-1101 American Moistening Co., 1214 American Radiator A Standard Sanitary Corp., 1328-1331 April Showers, Inc., 1459 Bahnson Co., The, 1102-1103 Baker Refrigeration Corp., 1225 Bell A Gossett Co., 1396-1397 Inc., 1210 Marley Co., Inc., The, 1211 Mario Coil Co., 1229 McQuay, Inc.. 1158-1159 Modine Mfg. Co., 1160-1161 National Radiator Co., The, 1340 1341 John J. Nesbitt, Inc., 1166 Niagara Blower Co., 1112 CONTROLLERS AND CON TROL EQUIPMENT OSes Hu midity and Temperature Control) Alco Valve Co., 1299 American Moistening Co., 1214 ' Bahnson Co., The, 1102-1103 Barber-Colman Co., 1269 Combustion Control Corp., 1301 Detroit Regulator Co., 1302 C. A. Dunham Co., 1415-1419 Fulton SylphoD Div., The, Robert- ghaw-Fulton Controls Co., 1304 1305 General Controls, 1312-1313 Hoffman Speciality Co., 1420-1423 ' HubbeU Corp., 1310 Illinois Engineering Co., 1424-1425 Johnson Service Co., 1312-1313 Jas. P. Marsh Corp., 1428-1429 Mercoid Corp., The, 1314 Minneapolis-Honeywell Regulator Co., 1316-1317 Parks-Cramer Co., 1114-1115 Penn Controls, Inc., 1319 Perfex Corporation, 1320 ` Photoswitch, Inc., (Affiliate of Com bustion Control Corp.), 1301 Powers Regulator Co., The, 1321 Sarcotherm Controls, Inc., 1433 Simplex Mfg. Co., 1323 Taylor Instrument Cos., 1326 CONTROLS, Water Level Maid-O'-Mist, Inc., 1426-1427 Bishop A Babcock Mfg. Co., The, (Massachusetts Blower Div.), 1237 Buensod-8tacey, Inc., 1104 Buffalo Forge Co., 1238 Carrier Corp., 1106-1107 DeBothezat Fans Div., American Machine A Metals, Inc., 1240 FeddeiB-Quigan Corp., 1153 Frigidaire, Div. of General Motors, 1110 General Electric Co., 1108-1109 Ingersoll Products Div., Borg-War ner Corp., 1481 Jenn-Air Products Co., 1245 Joy Mfg. Co., 1246-1247 Kennard Corp., 1157 Mario Coil Co., 1229 McQuay, Inc., 1158-1159 Meyer Furnace Co., The, 1130-1131 L. J. Mueller Furnace Co.. 1132-1133 D. J. Murray Mfg. Co., 1163 Niagara Blower Co., 1112 Parka-Cramer Co., 1114-1115 Ready Power Co., The, 1231 . Refrigeration Appliances, Inc., 1232 Refrigeration Economics Co., Inc., 1167 Refrigeration Engineering, Inc., 1233 Servel, Inc., 1137 Trane Co., The, 1168-1169 . United States Air Conditioning Corp., 1116 Utility Appliance Corp., 1140 _ Westinghouse Electric Corp., Air Patterson-Kelley Co., Inc., The, 1221 J. F. Pritchard A Co., 1212 Ready Power Co., The, 1231 Refrigeration Appliances, Inc., 1232 Refrigeration Economics Co., Inc., 1167 . Refrigeration Engineering, Inc., 1233 Servel, Inc., 1137 Trane Co., The. 1168-1169 Water Cooling Equipment Co., 1213 Westinghouse Electric Corp., Air Conditioning Div., 1117 Worthington Pump A Machinery Corp., 1118 Yamall-Waring Co., 1442 York Corp., 1119 Young Radiator Co., 1173 . COOLING TOWER FANS Baltimore Airooil Co., Inc., 1226 DeBothezat Fans Div., American Machine A Metals, Inc., 1240 ' Hartzell Propeller Fan Co., Div. of Castle Hills Corp., 1242 Lilie-Hoffmann Cooling Towers, Inc., 1210 Joy Mfg. Co., 1246-1247 Marley Co., Inc., The, 1211 J. F. Pritchard A Co., 1212 United States Air Conditioning Corp., 1116 . L. J. Wing Mfg. Co., 1170-1172 Conditioning Div., 1117 . CONVECTION HEATERS American Radiator A Standard Sanitary Corp., 1328-1331 C. A. Dunham Co., 1415-1419 Worthington Pump A Machinery Corp., 1118 York Corp., 1119 Young Radiator Co., 1173 COOLING TOWERS, Atmos pheric, Mechanical Draft, Forced Draft, Induced Draft, (Sec alto Codling Equipment, Fedders-Quigan Corp., 1153 Water) Kritxer Radiant Coils, Inc., 1222 COOLING EQUIPMENT, Oil Acme Industries, Inc., 1216 Modine Mfg. Co., 1169-1161 Acme Industries, Inc., 1216 National Radiator Co., The, 1340 Aerofin Corp., 1217-1219 Air A Refrigeration Corp., 1099 American Blower Corp., 1100-1101 1341 . Bell A Gossett Co., 1396-1397 Rome-Turney Radiator Co., The, Marley Co., Inc., The, 1211 Baker Refrigeration Corp., 1225 Baltimore Airooil Co., Inc., 1226 1223 Shaw-Perkins Mfg. Co., 1347 Niagara Blower Co., 1112 Binks Mfg. Co., 1206-1207 Patterson-Kelley Co., Inc., The, Buensod-Staoey, Inc., 1104 . Trane Co., The, 1168-1169 1221 . Carrier Corp., 1106-1107 Please mention THE GUIDE 1952 when writing to Advertisers Index to Modem Equipment 1079 Curtis Refrigerating MarhinA Div. of Curtis Mfg. Co., 1227 Fluor Corp., Ltd., The, 1208 Foster Wheeler Corp., 1209 Kennard Corp., 1157 Lilie-Hoffmann Cooling Towers, . Inc., 1210 Marley Co., Inc., The, 1211 Mario Coil Co., 1229 D. J. Murray Mfg. Co., 1163 J. F. Pritchard A Co., 1212 Refrigeration Appliances, Inc., 1232 Refrigeration Engineering, Inc., 1233 , ' Servel, Inc., 1137 United States Air Conditioning Corp., 1116 Vulcan Radiator Co., The, 1224 Water Cooling Equipment Co., 1213 CORK PRODUCTS (See Insu' lotion) Mundet Cork Corp., 1465 Minneapolis-Honeywell Regulator Refrigeration Engineering, Inc., Co,, 1316-1317 1233 Penn Controls, Inc., 1319 Trane Co., The, 1168-1169 Simplex Mfg. Co., 1323 United States Air Conditioning Spence Engineering Co., Inc., 1324 Corp., 1116 Westinghouse Electric Corp., Air DAMPER REGULATORS, Fur Conditioning Div., 1117 nace York Corp., 1119 ` . Field Control Div. of H. D. Conkey A Co , 1308 DEHYDRATORS, Refrigerant Fulton Sylphon Div., The, Robert- Henry Valve Co., 13)9 shaw-Fulton Controls Co., 1304 1305 General Controls, 1306-1307 Hart A Cooley Mfg. Co.. 1274-1275 DESTROYERS, Soot (See .Soot Destroyers) Minneapolis-Honeywell Regulator Co., 1316-1317 DETECTORS, Smoke (See Smoke Penn Controls, Inc., 1319 Simplex Mfg. Co., 1323 Detectors and Indicators, for Flue* and Ducts) . United States Register Co., 1288 . 1289 DIFFUSERS, Air (See Air Dif Young Regulator Co., 1291 ' fusers, and Ventilators, Floor and Wall) DAMPERS, Air Volume Control CORROSION, Treatment of Durant Insulated Pipe Co., 1453 Insul-Mastic Corp. of America; 1467 Owens-Coming Fiberglas Carp., 1451 H. W. Porter A Co., Inc., 1454 . Rio-wiL Co., The, 1455 Vinco Co., Inc., The, 1379-1371 Air Control Products, Ino., 1264-1265 Air Devices, Inc., 1178, 1263 AlftHHin Heating Corp., 1234 American Foundry A Furnace, Co. 1120-1121 Anemostat Corp. of America, 1266 1267 Bahnson Co., The, 1102-1103 Halt A Cooley Mfg., Co., 1274-1275 DISCS, Removable Composition Fairbanks Co., The, 1444 Jenkins Bros., 1447 DISTRICT HEATING (See Cor rosion, Treatment of--Expansion Joints--Insulation, Underground-- Meters, Pipe) COVERING, Pipe and Surface Armstrong Cork Co., 1464 Philip Carey Mfg. Co., The, 1448 1449 Durant Insulated Pipe Co., 1453 Gustin-Bacon Mfg. Co., 1450 - Infra Insulation, Inc., 1482 Insul-Mastic Corp. of America, 1467 Johns-ManvQle, 1470-1471 Kimberly Clark Corp., 1472-1473 Mundet Cork Corp., 1465 Owens-Coming Fiberglas Corp., 1451 Owens-Illinois Glass Co., Kaylo . Div., 1475 Pittsburgh Coming Corp., 1462-1463 *H. W. Porter A Co., Inc., 1454 Refiectal Corp., 1483 Rio-wiL Co., The, 1455 8prayo-Flake InmtUfa'nn Co.. 1476-- 1477 Johnson Servioe Co., 1312-1313 Minneapolis-Honeywell Regulator Co., 1316-1317 Parks-Cramer Co., 1114-1115 Powers Regulator Co., The, 1321 Titus Mfg. Corp., 1284-1285 ' Tuttle A Bailey, Inc., 1286-1287 United States Register Co., 1288 1289 Young Regulator Co., 1291 DAMPERS, Back Draft (JSee Dampers, Air Volume Control) DAMPERS, Flue Simplex Mfg. Co., 1323 - DAMPERS, Mechanical Johnson Service Co., 1312-1313 Minneapolis-Honeywell Regulator DISTRICT HEATING, Hightemperature Fluid Systems Durant Insulated Pipe Co., 1453 Z-Crete Div., Zonolite Co., 1458 DRAFT APPARATUS (See Blott ers, Forced Draft) DRAFT CONTROL, Barometric Field Control Div., of H. D. Conkey A Co.. 1308 National Radiator Co., The, 1340 1341 Perfex Corporation, 1320 Simplex Mfg. Co., 1323 Walker Mfg. A Sales Corp., 1327 Webster Engineering Co., 1379 DRYING EQUIPMENT Union Asbestos A Rubber Co.. Co.. 1316-1317 Air Devices, Inc., 1178, 1263 1456-1457 Grant Wilson, Inc., 1452 Powers Regulator Co., The, 1321 Young Regulator Co., 1291 Buffalo Forge Co., 1238 Electromode Carp., 1152 Z-Crete Div., Zonolite Co., 1458 Lee Corp., 1147 CUT-OFFS, Low Water General Controls, 1306-1307 Maid-O'-Mist, Inc., 1426-1427 McDonnell A Miller, Inc., 1372-1375 Mercoid Corp., The, 1314 Minneapolis-Honeywell Regulator Co., 1316-1317 National Radiator Co.. The, 1340- DEFLECTION GRILLE (See Grilles, Registers and Ornamental Meted Work, also Louvers, Registers) Air Control Products, Inc., 1264 1265 Diamond Mfg. Co., 1273 Hart A Cooley Mfg. Co., 1274-1275 Hendrick Mfg. Co., 1276-1277 Titus Mfg. Corp., 1284-1289 Modine Mfg. Co., 1160-1161 National Heater Co., 1148-1149 Niagara Blower Co., 1112 Arthur A. Olson A Co., 1150 Trane Co., The, 1168-1169 DUCT INSULATION (See Insu lation, Duets, Ventilating, Air Conditioning) Penn Controls, Inc., 1319 Warren Webster & Co., 1437-1441 DAMPER REGULATOR SETS Tuttle A Bailey, Inc., 1286-1287 United States Register Co., 1288 1289 Young Regulator Co., 1291 DUCT SYSTEMS, Gravity and Forced Air Clayton A Lambert Mfg. Co., 1123 Air Control Products, Ino., 1284-1265 American Radiator A Standard Sanitary Corp., 1328-1331 Barber-Colman Co., '* ` DEHUMIDIFIERS Air A Refrigeration Corp** 1099 Airtemp Div., Chrysler Corp., 1126- DUCTS, Prefabricated Philip Carey Mfg. Co., The, 1448 1449 FiAdr0niSrai D`T' f H` D` Conkey American Blower Corp.. 1100-1101 Clayton A Lambert Mfg. Co., 1123 a ... ,, Bahnson Co.. The, 1102-1103 MC?"l31W3j?neyWeU Begulator B^^<LsSSy?lSc!fn04 Johna-Manville, 1470-1471 L. J. Mueller Furnace Co., 1132-1133 United States Register Co., 1288- NSmMtor Co.. The, .340- 1341 Penn Controls, Inc., 1319 Perfex Corporation, 1320 Tuttle A Bailey, Inc., 1286-1287 Young Regulator Co., 1291 DAMPER REGULATORS, Boiler (See Regulators) Fedders-Quigan Carp., 1153 Mario Coil Co., 1229 New York Blower Co., The, 1250 Niagara Blower Co., 1112 Parks-Cramer Co., 1114-1115 Pittsburgh Lectrodryer Corp., 1113 J. F. Pritchard A Co., 1212 Ready Power Co., The, 1231 DUST COLLECTING EQUIP MENT American Air Filter Co., Inc., 1183 1185 American Blower Corp., 1100-1101 V. D. Anderson Co., The, 1410-1411 Buffalo Forge Co., 1238 General Blower Co., 1241 Numerals following Manufacturers* Names refer to pages In die Catalog Data Section 1080 1952 Guide Trion, Inc., 1202 Flexonica Carp., Expansion Joint Air Conditioning Co., Inc., Wilson A Co, Inc., 1205 Div, (Formerly Chicago Metal 1111 Boee Corp.),|1294 Hg Electric Ventilating Co., 1155, DUST COLLECTORS. Cloth Type American Air Filter Co., Inc., 1183-- 1185 Foster Wheeler.Corp, 1209 Fulton Sylphon Div., The, Robert- shaw-Fulton Controls Co., 1304 1305 Arthur Harris A Co, 1295 1244 Morrison Products, Ino., 1249 L. J.Mueller Furnace Co., 1132-1133 Herman Nelson Div., American Air Filter Co., Inc., 1164-1105 EJECTORS, Sewage Chicago Pump Co., 1403 Illinois Engineering Co., 1424-1425 New York Blower Co., The, 1250 Owens-Coming Fiberglas Corp., Niagara Blower Co., 1112 1451 Tornngton Mfg. Co., The, 1252-1253 H. W. Porter A Co., Inc, 1454 Trade-Wind Motorfans, Inc., 1254 ELECTROSTATIC AIR Yamall-Waring Co., 1442 - Trane Co., The, 1168-1169 CLEANERS Young Regulator Co., 1291 Utility Appliance Corp., 1140 Air-Mace Carp., 1180-1182 Western Blower Co., 1255 American Air filter Co., Inc., 1183-- 1185 Trion, Inc.,-1202 Westinghouse Electric Corp., Sturtevant Div, 1204, 1250 EXPANSION LOOPS Durant Insulated Pipe Co., 1453 Rio-wiL Co., The, 1455 Z-Crete Div., Zonolite Co., 1458 Wilson A Co., Inc., 1205 . EXPOSITIONS Westinghouse Electric Corp., Stur- tevant Div., 1204, 1256 FANS, Electric ' Philip Carey Mfg. Co., The, 1448 1449 ELECTROSTATIC FILTERS, International Exposition Co., 1395 Champion Blower A Forge Co, 1239 General Blower Co, 1241 Trion, Inc., 1202 FAN BLADES Tornngton Mfg. Co., The, 1252-1253 Hunter Fan A Ventilating Co, Inc, 1243 Hg Electric Ventilating Co, 1156, ELIMINATORS, Air 1244 Maid-O'-Mist, Inc., 1426-1427 FAN MOTORS (See Motors, Elec Propellair Div, Robbins A Myers, tric) Inc, 1251 .. EVAPORATIVE CONDENSERS (See Condenser* arid Evaporators) EVAPORATORS FAN STACKS Dutton Boilers, Division Hapman- Dutton Co., 1358 Tornngton Mfg. Co, The, 1252-1253 Trade-Wind Motorfans, Inc., 1254 Western Engineering A Mfg. Co, Ino, 1262 L. J. Wing Mfg. Co, 1170-1172 American Blower Corp., 1100-1101 Bell A Gossett Co., 1396-1397 Buffalo Forge Co., 1238 Farrar A Trefta, Inc, 1359 Foster Wheeler Corp., 1209 Arthur Harris A Co., 1296 Mario Cofl Co., 1229 Refrigeration Appliances, Inc, 1232 Refrigeration Engineering, Inc., 1233 . Rome-Tumey Radiator Co., The, 1223 Trane*Co.. The, 1168-1169 Westinghouse Electric Corp., Air Conditioning Div., 1117 - Young Radiator Co., 1173 FANS, Attic American Blown Corp., 1100-1101 American Coolair Corp., 1235 Buffalo Forge Co., 1238 Philip Carey Mfg. Co., The, 1448 1449 Champion Blower A Forge Co., 1239 DeBothezat Fans Div., American Machine A Metals, Inc., 1240 General Blower Co., 1241 Hunter Fan A Ventilating Co., Ino., 1243 Hg Electric Ventilating Co., Ine., 1156 1244 ' Jenn-Air Products Co., 1245 Lau Blower Co., The, 1248 FANS, Furnace Aladdin Heating Corp, 1234 American Blower Corp, 1100-1101 Bishop A Babcock Mfg. Co, The, (Massachusetts Blower Div.), 1237 Champion Blower A Forge Co, 1239 DeBothezat Fans Div, American Machine A Metals, Inc., 1240 . Joy Mfg. Co, 1246-1247 Meyer Furnace Co, The, 1130-1131 Morrison Products, Inc, 1249 L. J. Mueller Furnace Co, 1132-1133 United States Air Conditioning Corp, 1116 L. J. Wing Mfg. Co, 1170-1172 EXHAUST Exhaust) HEADS (See Heads, H. J. Somers, Inc., 1200-1201 Tarrington Mfg. Co., The, 1252-1253 Trade-Wind Motorfans, Inc., 1254 FANS, INDUCED DRAFT American Blower Corp, 1100-1101 Buffalo Forge Co, 1238 EXHAUST TUBING, Flexible (See Tubing, Flexible, Metallic) EXHAUSTERS Air Devices, Inc., 1178, 1263 American Blower Corp., 1100-1101 FANS, Axial Flow American Blower Corp., 1100-1101 Bahnson Co., The, 1102-1103 Baltimore Aircoil Co., Ino., 1226 Buffalo Forge Co., 1238 Hartzell Propeller Fan Co., Div. of Champion Blower A Forge Co, 1239 Clarage Fan Co, 1105 DeBothezat Fans Div, American Machine A Metals, Ino, 1240 General Blower Co, 1241 L. J. Wing Mfg. Co, 1170-1172 Bayley Blower Co., 1236 Castle Hills Corp., 1242 G. C. Bieidert Co., 1258 Hunter Fan A Ventilating Co., 1243 FANS, Portable Buffalo Forge Co., 1238 Hg Electric Ventilating Co-, 1156, Baltimore Aircoil Co, Ino, 1226 Champion Blower A Forge Co., 1239 1244 Champion Blower A Forge Co, 1239 DeBothezat Fans Div., American Joy Mfg. Co., 1246-1247 General Blower Co, 1241 A Metals, Inc., 1240 New York Blower Co., The, 1250 Hartzell Propeller Fan Co, Div. of General Blower Co., 1241 Propellair Div., Robbins A Myers, Castle Hills Corp, 1242 Hartsell Propeller Fan Co., Div. of Inc., 1251 Hunter Fan A Ventilating Co, Ino., Castle Hills Corp., 1242 Western Engineering A Mfg. Co., 1243 Hg Electric Ventilating Co., 1156, Inc., 1262 Hg Electric Ventilating Co, 1156, 1244 Westinghouse Electric Corp., Stur- 1244 . Jenn-Air Products Co., 1245 tevant Div., 1204, 1256 Lau Blower Co, The, 1248 Joy Mfg., Co., 1246-1247 L. J. Wing Mfg. Co, 1170-1172 Herman Nelson Div., American Air John J. Nesbitt, Inc, 1166 Filter Co, Inc, 1164-1165 New York Blower Co., The, 1250 Bwartwout Co., The, 1261 Trade-Wind Motorfans, Inc., 1254 Trane Co., The, 1168-1169 United 8tates Air Conditioning Carp., 1116 Western Engineering A Mfg. Co., Inc., 1262 Westinghouse Electric Carp., Stur- tevant Div., 1204, 1256 L. J. Wing Mfg. Co., 1170-1172 FANS, Centrifugal Aladdin Heating Corp, 1234 American Blower Corp, 1100-1101 American Foundry A Furnace Co., 1120-1121 Bayley Blower Co, 1236 ' Bishop A Babcock Mfg. Co.,' The, (Massachusetts Blower Div.), 1237 Buffalo Forge Co, 1238 Campbell Heating Co, 1124-1125, 1142 Propellair Div, Robbins A Myers, Inc, 1251 Torrington Mfg. Co, The, 1252-1253 L. J. Wing Mfg. Co, 1170-1172 FANS, Propeller American Blower Corp, 1100-1101 American Coolair Corp, 1235 Baltimore Aircoil Co, Inc, 1226 Bishop A Babcock Mfg. Co, The (Massachusetts Blower Div.), 1237 E, K. Campbell Co, 1143 Buffalo Forge Co, 1238 EXPANSION JOINTS Champion Blower A Forge Co, 1239 DeBothezat Fans Div, American Badger Mfg. Co., 1293 Clarage Fan Co, 1105 Machine A Metals, Inc, 1240 Celotex Corp., The, 1466 General Blower Co, 1241 General Blower Co, 1241 - Please mention THE GUIDE 1952 when writing to Advertisers Index to Modem Equipment 1081 Hartzell Propeller Fan Co, Div. of Castle Hills Corp, 1242 Hunter Fan A Ventilating Co, Inc, 1243 Hg Electric Ventilating Co, 1156, 1244 Jenn-Air Products Co, 1245 Lau Blower Co, The, 1248 Herman Nelson Div, American Air Filter Co, Inc, 1164-1165 - New York Blower Co, The, 1250 J. F. Pritchard A Co, 1212 Propellair Div, Robbins A Myere, Inc, 1251 ' Torrington Mfg. Co, The, 1252-1253 Trade-Wind Motorfans, Inc., 1254 Trane Co, The, 1168-1169 Western Blower Co, 1255 Western Engineering A Mfg. Co, Inc, 1262 L. J. Wing Mfg. Co, 1170-1172 FANS, Supply and Exhaust Aladdin Heating Corp, 1234 American Blower Corp, 1100-1101 American Coolair Corp, 1235 Bayley Blower Co, 1236 Bishop A Babcock Mfg. Co, The (Massachusetts Blower Div.), 1237 Buffalo Forge Co, 1238 Philip Carey Mfg. Co, The, 1448 1449 Champion Blower A Forge Co, 1239 Clarage Fan Co, 1105. DeBothezat Fans Div, American Machine A Metals, Ino.) 1240 General Blower Co, 1241 Hartzell Propeller Fan Co, Div. of Castle Hills Corp, 1242 Hunter Fan A Ventilating Co, Inc, 1243 Hg Electric Ventilating Co, 1156, 1244 Jenn-Air Products Co, 1245 Joy Mfg. Co, 1246-1247 Lau Blower Co, The, 1248 Herman Nelson Div, American Air Filter Co, Inc, 1164-U65 New York Blower Co, The, 1250 Niagara Blower Co.. 1112 `Propellair Div, Robbins A Myers, Inc, 1251 Trane Co, The, 1168-1169 United States Air Conditioning Corp, 1116 Westinghouse Electric Corp, Sturtevant Div, 1204, 1256 L. J. Wing Mfg. Co, 1170-1172 FANS, Ventilating (See Fans, Attic, Axial Flow, Centrifugal, etc.) FEED WATER HEATERS (See Heaters, Feed Water) FEED WATER REGULATORS CSee Regulators, Feed Water) FEEDERS, Boiler Water Cyclotherm Corp, 1356 Maid-O'-Mist, Inc, 1426-1427 McDonnell A Miller, Inc, 1372-1375 Penn Controls, Inc, 1319 Warren Webster A Co, 1437-1441 Grant Wilson, Ine, 1452 Clayton A Lambert Mfg. Co, 1123 Wood Conversion Co, 1479 Meyer Furnace Co, The, 1130-1131 L. J. Mueller Furnace Co, 1132-1133 FIBER INSULATION (See In- United States Register Co, 1288- sulation) ' ' 1289 FILTERS, Air (See Air Cleaning FITTINGS, Hot Water Heating Equipment) Systems Air A Refrigeration Corp, 1099 Hammond Brass Works, 1445 Air Devices, Inc, 1178, 1263 Jas. P. Marsh Corp, 1428-1429 Air Filter Corp, 1177 National Radiator Co, The, 1340 Air Maze Corp, The, Detroit Air 1341 Filter Div, 1182 Pacific Steel Boiler Div, U. S. Ra American Air Filter Co, Inc, 1183-- diator Corp, 1342-1343 1185 Sarco Co, Inc, 1434-1435 American Moistening Co, 1214 Sarcotherm Contois, Inc, 1433 American Radiator A Standard Taco Heaters, Inc, 1400 Sanitary Corp, 1328-1331 ' H. A. Thrush A Co, 1398-1399 V. D. Anderson Co, The, 1410-1411 Trane Co, The, 1168-1169 Bahnson Co, The, 1102-1103 United States Radiator Corp, 1344 Bishop A Babcock Mfg. Co, The, 1345 (Massachusetts Blower Div.), 1237 Continental Air Filters, Ino, 1192 DoUinger Corp, 1194-1195 Farr Co, 1196-1197 Glasfioss, 1193 FITTINGS, Jacketed Steam nii Oil Parks-Cramer Co, 1114-1115 Owens-Coming Fiberglas Corp, 1198 . FITTINGS,. Pipe, Add Resisting Research Products Corp, 1199 TAdish Co, 1296 `. * H. J. Somera, Inc, 1200-1201 Taylor Forge A Pipe Works, Inc, Trion, Inc, 1202 1297 Vortox Co, 1203 Wilson A Co, Inc, 1205 FITTINGS, PIPE, ALLOY AND . STAINLESS, Non-Ferrous FILTERS, Air, Continuous, Ladish Co, 1298 Automatic Taylor Forge A Pipe Works, 1297 American Air Filter Co, Inc., 1183^- Tube Turns, Ine., 1298 1185 V. D. Anderson Co, The, 1410-1411 Bahnson Co, The, 1102-1103 Continental Air Filters, Inc, 1192 DoUinger Corp, 1194-1195 Farr Co, 1196-1197 FITTINGS, Pipe, Flanged GrinneU Co, Inc, 1154-1155 Henry Valve Co, 1309 Taylor Forge A Pipe WorkB, 1297 FILTERS, Electrostatic Precipi York Corp, 1119 ' tators Air-Maze Corp, 1180-1182 FITTINGS, Pipe forUnder* ground Conduit FILTERS, Gas Air-Maze Corp, 1180-1182 American Air Filter Co., Inc, 1183 'Durant Insulated Pipe Co, 1453 H. W. Porter A Co, Inc, 1454 Rio-wiL Co, The, 1455 1185 American Solvent Recovery Corp, FITTINGS, Pipe, Galvanized 1186-1187 . GrinneU Co, Inc, 1154-1155 V. D. Anderson Co, The,' 1410-1411 Ladish Co., 1296 ' W. B. Connor Engineering Corp, Taylor Forge A Pipe Works, Inc, 1188-1191, 1270-1271 1297 DoUinger Corp, 1194-1195 . . Trion, Inc., 1202 . ' _ FITTINGS, Pipe, Screwed FILTERS, Grease Air Devices, Inc., 1178, 1263 Air Filter Corp, 1177 GrinneU Co, Ino, 1154-1155 Henry Valve Co, 1309 . Ladish Co, 1296 _ ' . ` Air-Maze Corp, 1180-1182 American Air Filter Co, Inc, 1183 FITTINGS, Pipe, Seamless Weld 1185 ing Continental Air Filters, Inc, 1192 Ladish Co, 1296 - DoUinger Carp, 1194-1195 Farr Co, 1196-1197 Research Products Corp., 1199 FITTINGS, Pipe, Socket-Weld. Ing Ladish Co, 1296 FILTERS. Liquid Air-Maze Corp, The, 1180-1182 DoUinger Corp, 1196-1195 FITTINGS, Pipe, Solder American Brass Co, The, 1474-1475 FELT, Insulating (See Insulation Fdt) FELT, Sound Deadening Armstrong Cork Co, 1464 Philip Carey Mfg. Co, The, 1448 1449 Johns-Manville, 1470-1471 Kimberly-Clark Corp, 1472-1473 Lockport Cotton Batting Co, 1474 Owens-Coming Fiberglas Corp, 1451 Union Asbestos A Rubber Co, 1456 1457 FILTERS. Odors American Solvent Recovery Corp, 1186-1187 W. B. Connor Engineering Corp, 1188-1191, 1270-1271 FIREBRICK, Insulating Armstrong Cork Co, 1464 Babcock A Wilcox Co, The, 1352 Johns-Manville, 1470-1471 FITTINGS, Air Conditioning and Warm Air Furnace (See Furnace Pips and Fittings) FITTINGS, Pipe, Steel Henry Valve Co.', 1309 . Ladish Co, 1296 Taylor Forge A Pipe Works, Inc, 1297 Tube Turns, Inc, 1298 FITTINGS, Welding GrinneU Co, Inc, 1154-1155 Ladish Co, 1298 Taylor Forge A Pipe Works, Inc, 1297 Tube Turns, Inc, 1298 Numerals following Manufacturers* Names refer to pages In the Catalog Data Section 1082 1952 Guide FLANGES, Galvanized or NonFerrous Simplex Mfg. Co., 1323 United States Air Conditioning 'American Furnace Co., 1122 Corp., 1116 American ~Rnr^tnr A Standard Water-Cooling Equipment Co., 1213 Sanitary Corp., 1328-1331 Campbell Heating Co.. 1124-1125, FLANGES, Lead, Roof Simplex Mfg. Co., 1323 FLANGES, Pipe, Alloy, less Non-Ferrous Ladish-Co., 1298 . Staln- FUTASEufLtJoSBmLUIanRticiNI(NSeGa EQUIPMENT, FBtuZrrnneJr*s, AAvuttool- - matte; Gas Burners; OH Burner*; Sicker) FUEL OIL, Heating. Pumping and Straining Units Ace Engineering Co., 1382 .1142 CEhleiccatrgoomSotdeeelrCFourrpn.a,c11e1155C92o.. 1146 Fitsgibbons Boiler Co., Inc., 1360 1361 General Automatic Products Corp., 1338 General Electrio Co., 1108-1109 Hayes Furnace Mfg. A Supply Co., FLANGES, Pipe, Blind Grinnell Co., Inc., 1154-1155 Ladiah Co., 1296 m, Taylor Forge A Pipe Works, Inc., 1297 Bell A Gossett Co., 1396-1397 S. T. Johnson Co., 1386-1387 Ray Oil Burner Co., 1390-1391 FURNACE PIPE AND FITTINGS 1128 Hoffman Specialty Co., 1420-1423 S. T. Johnson Co., 1388-1387 H. C. Little Burner Co., 1385 Meyer Furnace Co., The, 1130-1131 L. J. Mueller Furnace Co., 1132-1133 Clayton A Lambert Mfg. Co., 1123 Norge Heat, Div. of Borg-Warner FLANGES, Pipe, Reducing Grinnell Co., Inc., 1154-1155 Ladiah Co., 1296 _ Taylor Forge A Pipe Works, Inc^ 1297 Tube Turns, Inc., 1298 . Meyer Furnace Co., The, 1130-1131 L. J. Mueller Co., The, 1132-1133 United States Register Co., 1288- FURNACES, Electric Electromode Corp., 1152 _^Corp., 1134-1135 Petroleum Heat A Power Co., 1388-- 1389 Ray Oil Burner Co., 1390-1391 Rheem Mfg. Co., 1136 Syncromatic Corp., 1129 United States Radiator Corp., 1344 1345 FLANGES, Pipe, Steel Utility Appliance Corp., 1140 Grinnell Co., Inc., 1154--1155 FURNACES, Gas-Fired, Floor Waterman-Waterbury Co., The, jAHifth Co., 1296 American Radiator A Standard 1138-1139 . Taylor Forge & Pipe Works, Inn* Sanitary Corp., 1328-1331 Williams Oil-O-Matic Div., Eureka 1297 Tube Turns, Inc., 1298 Williams Corp., 1393 FURNACES, On Burning, Floor John Zink Co., 1380-1381 Airtherm Mfg. Co., 1141 ' FLANGES, Welding Grinnell Co., Inc., 1154-1155 lldwh Co., 1296 Taylor Forge & Pipe Works, Inc., 1297 Tube Turns, Inc., 1298 American Foundry A Furnace Co., 1120-1121 American Radiator A Standard Sanitary Corp., 1328-1331 . Chicago Steel Furnace Co., 1146 Dravo Corp., 1144-1145 Lee Corp., 1147 . GAGES. Altitude Electrio Auto-Lite Co., The, Instru ment A Gauge Div., 1303 Jas. P. Manh Corp., 1428-1429 GAGES, Compound H. C. Little Burner Co., 1385 C. A. Dunham Co., 1415-1419 FLOATS, Ferrous and Ferrous (Seamiest) Arthur Harris A Co., 1295 Non- National Heater Co., 1148-1149 Arthur A. Olson A Co., 1150 FURNACES, Suspended Electric Auto-Lite Co., The, In strument A Gauge Div., 1303 Jas. P. Marsh Corp., 1428-1429 FLOATS, Welded W. H. Nicholson A Co., 1430-1431 Chicago Steel Furnace Co., 1146 FURNACES, Wall GAGES, Liquid Level . Minneapolis-Honeywell Regulator Co., 1316-1317 H. C. Little Burner Co., 1385 Rochester Mfg. Co., Inc., 1322 Rheem Mfg. Co., 1136 &SS5 IfcdSS Co.. The. 1S40- John ZinkCo.. 1380-1381 Taylor Instrument Cos., 1326 Yamall-Waring Co., 1442 1341 Pacific Steel Boiler Div., U. 8. FURNACES, Warm Air, Heavy .' Ffn-Kfttnr Corp., 1342-1343 Duty United States Radiator Corp., 1344 Air Devices, Inc., 1178, 1263 1345 United States Steel, 1292 Airtherm Mfg. Co., 1141 Aladdin Heating Corp., 1234 Amariwin Foundry A Furnace Co., 1120-1121 FLUE GAS ANALYSIS E. K. Campbell Co., 1143 Minneapolia-HoneyweU ' Regulator Campbell Heating Co., 1124-1125, Co,, 1316-1317 1142 Chicago Steel Furnace Co., 1146 GAGES, Pressure C. A. Dunham Co., 1415-1419 Electrio Auto-Lite Co., The, Instru ment A Gauge Div., 1303 Jas. P. Marsh Corp., 1428-1429 Minneapolia-HoneyweU Regulator Co., 1316-1317 Perfex Corporation, 1320 Rochester Mfg. Co., Inc., 1322 Taylor Instrument Cos., 1326 FOOD SAVERS o American Solvent Recovery Corp., 1186-1187 .,, W. B. Connor Engineering Corp., 1188-1191, 1270-1271 Dravo Corp., 1144-1145 Hayes Furnace Mfg. A Supply Co., 1128 Lee Corp., 1147 H. C. Little Burner Co., 1385 Meyer Furnace Co., The,-1130-1131 GAGES, Steam Dole Valve Co., The, 1443 C. A. Dunham Co., 1415-1419 Electric Auto-Lite Co., The, Instru ment A Gauge Div., 1303 L. J. Mueller Furnace Co., 1132-1133 Woffmaw Specialty Co., 1420-1423 TFi9j-LiTffinlprTi ato?nKiif-2rcHSEi7i"i'ir>' National Heater Co., 1148 1149 Arth-AOhon* Co., 1150 TINGS (See Duett; Fitting) Ray Oil Burner Co., 1390-1391 Jas. P. Marsh Corp., 1428-1429 Minneapolis-Honeywell Regulator Co,, 1318-1317 Rheem Mfg. Co., 1136 FORCED DRAFT COOLING TOWERS (See Codling Towers, Induced Draft, Mechanical Draft) Acme Industries, Inc., 1216 Air A Refrigeration Corp., 1099 Balfpr Refrigeration Corp., 1225 Fluor Corp., Ltd., The, 1208 Foster Wheeler Corp., 1209 Syncromatic Corp., 1129 United States Radiator Corp., 1344--1345 Waterman-Waterbury Co.,. The, 1138-1139 John Zink Co., 1380-1381 FURNACES, Warm Air, Resi- GAGES, Tank . Minneapolis-Honeywell Regulator Co., 1316-1317 Rochester Mfg. Co., Inc., 1322 GAGES, Vacuum Dole Valve Co., The. 1443 Kennard uCoorrp., n11o57/ adence C. A. Dunham Co 1415-1419 T Coding Towers, Airtemp Div., Chrysler Corp., 1126- Electrio Auto-Lite Co., The, Iostru- Tnrt _ 1210 1127 ment A Gauge Div., 1303 Mario Coil Co.. 1229 Aladdin Heating Corp., 1234 Jas. P. Marsh Corp.. 1428-1429 J. F. Pritchard A Co., 1212 American Foundry A Furaaee Co., Minneapolis- Honeywell Regulator RgfrigpmtioP F.wgitiPiaring, Ine.f 1233 1120-1121 Co* 1316-1317 . Please mention THE GUIDE 1952 when writing to Advertisers Index to Modem Equipment 1083 Moeller Instrument Co., 1318 Barber-Colman Co., 1269 HEATERS, Air > Rochester Mfg. Co., Inc., 1322 Diamond Mfg. Co., 1273 Aerofin Corp., 1217-1219 .Taylor Instrument Cos., 1326 Dole Valve Co., The, 1443 Air Devices, Inc., 1178, 1263 Hart A Cooley Mfg. Co,, 1274-1275 Airtherm Mfg. Co., 1141 GAGES, Vapor C. A. Dunham Co., 1415-1419 Hendrick Mfg. Co., 1276-1277 American Foundry A Furnace Co., Independent Register Co., The, 1278 1120-1121 Minneapolis-Honeywell Regulator Minneapolis-Honeywell Regulator Bahnson Co., The, 1102-1103 Co., 1316-1317 Co., 1316-1317 Buffalo Forge Co., 1238 Pyle-National Co., The, Multi E. K. Campbell Co., 1143 GAGES, Water Yarnall-Waring Co., 1442 Vent Div., 1280-1281 Campbell Heating Co., 1124-1125, Register A Grille Mfg. Co., Inc., 1279 1142 GAS BURNERS Airtemp Div., Chrysler Corp., 1126-1127 American Furnace Co., 1122 American Radiator A Standard Sanitary Corp., 1328-1331 Babcock A Wilcox Co., The, 1352 Standard Stamping A Perforating Co., 1282 Stewart Mfg. Co., Inc., 1283 Titus Mfg. Corp.. 1284-1285 Tuttle A Bailey, Incl, 1286-1287 United States Register Co , 1288 1289 Young Regulator Co., 1291 Chicago Steel Furnace Co-, 1146 Combustion Engineering - Super heater, Inc., 1354-1355 Dravo Corp., 1144-1145 Electromode Corp., 1152 GrinneU Co., Inc., 1154-1155 Lee Corp., 1147 McQuay, Inc,, 1158-1159 Crane Co., 1336-1337 Hook A Ackerman, Inc., 1339 Meyer Furnace Co., The, 1130-1131 L. J. Mueller Furnace Co., 1132-1133 Norge Heat, Div. of Borg-Warner Corp., 1134-1135 Ray Oil Burner Co., 1390-1391 C. L. Rayfield Co., 1392 Sonner Burner Co., 1378 United States Radiator Corp., 1344 1345 Utility Appliance Corp., 1140 HANGERS, Pipe Grinnell Co., Inc., 1154-1155 HANGERS, Radiator - Carty A Moore Engineering Co., 1414 National Radiator Co., The., 1340 1341 United States Radiator Corp., 1344 1345 Meyer Furnace Co., The, 1130-1131 Modine Mfg. Co,, 1160-1161 L. J. Mueller-Furnace Co., 1132-1133 National Heater Co., 1148-1149 National Radiator Co., The, 1340 1341 Herman Nelson Div., Amgrlwm Air Filter Co., Inc., 1164-1165. Arthur A. Olson A Co., 1150 Refrigeration Engineering, Inc., 1233 Syncromatic Corp., 1129 Waterman-Waterbury Co., The, 1138-1139 . Webster Engineering Co., The., 1379 John Zink Co., 1380-1381 GAS BURNERS (See Combination, etc.) HEADS, Exhaust V. D. Anderson Co., The, 1410-1411 HEADS, Sprinkler (Fire Protec tion) Grinnell Co., Inc., 1154-1155 Trane Co., The, 1168-1169 Westinghouse Electric Corp., Sturtevant Div., 1204, 1256 L. J. Wing Mfg. Co., 1170-1172 Young Radiator Co., 1173 John Zink Co., 1380-1381 GAS FILTERS (See Fillers, Gas) GAS SAFETY PILOTS (See Pilots) ' GASKETS, Asbestos Grant Wilson, Inc., 1452 GASKETS, Cork Armstrong Cork Co., (Industrial. _ Div.), 1464 Mundet Cork Corp., 1465 GLASS (See Insulation, Cellular Glass) GLASS BLOCK ROOFLIGHTS (See Skylights) GLASS BLOCKS American Structural Products Co., 1460 . American 3 Way-Luxfer Prism Co., 1461 Pittsburgh Corning Corp., 1462-1463 GLASS, Cellular Armstrong Cork Co. (Building Ma terials Div.), 1464 ' Pittsburgh Corning Corp., 1462-1463 HEAT EXCHANGERS Acme Industries, Inc., 1216 Aerofin Corp., 1217-1219 - Bell A Gossett Co., 1396-1397 Binks Mfg. Co., 1206-1207 Farrar A Trefts, Inc., 1359 Frick Co., Inc., 1228 Hayes Furnace Mfg. A Supply Co., > 1128 Mario Coil Co.. 1229 McQuay, Inc., 1158-1159 - Modine Mfg. Co., 1160-1161 National Radiator Co., The, 1340 1341 John J. Nesbitt, Inc., 1166 Niagara Blower Co., 1112 Patterson-KeUey Co., Inc., The, 1221 J. E. Pritchard A Co., 1212 Refrigeration Economics Co., Inc., 1167 Rome-Turney Radiator Co., The, 1223 H. A. Thrush A Co.. 1398-1399 Trane Co., The, 1166-1169 . United States Radiator Corp., 1344 1345 Western Blower Co., 1255 _ Worthington Pump A Machinery Corp., 1118 York Corp., 1119 HEATERS, Automatic -Hot Water, Domestic Airtemp Div., Chrysler Corp- 1126 1127 American Radiator A Standard Sanitary Corp., 1328-1331 ' Combustion Engineering - Super heater Inc., (Chattanooga Div.), 1354-1355 Crane Co., 1336-1337 Dewey-Shepard Boiler Co., 1357 Frigidaire Div., General Motors Corp., 1110 S. T. Johnson Co., 1386-1387 National Radiator Co., The, 1340 1341 . Norge Heat, Div. Borg-Warner Corp., 1134-1135 Pacific Steel Boiler Div., U. S. - Radiator Corp,, 1342-1343' Petroleum Heat A Power Co., 1388 1389 Ray Oil Burner Co., 1390-1391 Rheem Mfg. Co., 1136 United States Radiator Corp., 1344 1345 York-Shipley, Inc., 1394 HEATERS, Blast Aerofin Corp., 1217-1219 Airtherm Mfg. Co., 1141 Young Radiator Co., 1173 Carrier Corp., 1106-1107 GOVERNORS, Pump Electromode Corp., 1152 McDonnell A Miller, Inc., 1372-1375 Spence Engineering Co., Inc., 1324 Warren Webster A Co., 1437-1441 HEAT RECLAIMERS Patterson-KeUey Co., Inc., 1221 C. L. Rayfield Co., 1392 The, GAO Mfg. Co., The, 1220 ' Hastings Air Conditioning Co., Inc., 1111 McCord Corp., 1162 GRATES FOR'BOILERS AND McQuay, Inc., 1158-1159 FURNACES Combustion Engineering - Super heater, Inc., 1354-1355 HEAT SURFACE Aerofin Corp., 1217-1219 GAO Mfg. Co., The, 1220 Kritser Radiant Cods, Inc.. 1222 GREASE FILTERS (See Filters, McQuay, Ioc., 1158-1159 Grease) Modine Mfg. Co., 1160-1161 John J. Nesbitt, Inc., 1166 . GRILLES, REGISTERS AND New York Blower Co., 1250 ORNAMENTAL METAL Niagara Blower Co., 1112 WORK (See also Louvers, Reg-. Rome-Turney Radiator Co., The, itlers) 1223 Modine Mfg. Co., 1160-1161 D. J. Murray Mfg. Co.. 1163 Niagara Blower Co., 1112 Rome-Turney Radiator Co., The, 1223 Trane Co., The, 1168-1169 United States Air Conditioning Corp., 1116 . Westinghouse Electric Corp., Stur- tevant Div., 1204, 1256 Young Radiator Co., 1173 Air Control Products Inc., 1264-1265 Vulcan Radiator Co., The, 1224 Auer Register Co., The, 1268 Warren Webster A Co., 1437-1441 Bahnson Co., The. 1102-1103 Young Radiator Co., 1173. HEATERS, Cabinet Electromode Corp., 1152 ----- If._Namaa rpfr i the Catalog Data Section 1084 1952 Guide Modine Mfg. Co., 1160-1101 Ray Oil Burner Co., 1390-1391 L. J. Mueller Furnace Co., 1132-1133 Trane Co., The, 1168-1169 Rheem Mfg. Co., 1136 D. J. Murray Mfg. Co., 1163 Young Radiator Co., 1173 H. B. Smith Co., Inc., The. 1350 National Heater Co., 1148-1149 Spencer Heater, Lycoming-Spencer National Radiator Co., The, 1340 HEATERS, Baseboard Heaters) Convection (See Heating, Convection Div., Avco Mfg. Corp., 1348-1349 1341 # Titusville Iron Works Co., The, -Herman Nelson Div., American (Div. of Struthers-Welb Corp.), Air Filter Co., Inc., 1164-1165 . 1368 John J. Nesbitt, Inc., 1166 HEATERS, Duct Type Hayes Furnace Mfg. A Supply Co., 1128 United States Radiator Corp., 1344 1345 Vapor Heating Corp., 1369 . Weil-McLain Co., 1351 New York Blower Co., 1250 Niagara Blower Co., 1112 Arthur A. Olson A Co., 1150 Pacific Steel Boiler, Div., U. S. York-Shipley, Inc., 1394 Radiator Corp., 1342-1343 . HEATERS, Electric Electromode Corp., 1152 Fluid Systems, Inc., 1376-1377 HEATERS, Indirect Aerofin Corp.. 1217-1219 Bell A Gossett Co.. 1398-1397 Refrigeration Engineering, Ino.,1233 Rheem Mfg. Co., 1136 ' Rome-Turney Radiator Co., The, 1223 - HEATERS, Feed Water Bell A Gossett Co., 1396-1397 Foster Wheeler Corp., 1209 Warren Webster A Co., 1437-1441 Worthington Pump A Machinery Corp., 1118 Campbell Heating Co., 1124-1125, 1142 . Pacific Steel Boiler Div., U. S. Radiator Corp., 1342-1343 Patterson-Kelley Co., Inc., The, 1221 Taco Heaters, Inc., 1400 Sonner Burner Co., 1378 Trane Co., The, 1168-1169 United States Air Conditioning Corp., 1118 United States Radiator Corp., 1344 1345 Utility Appliance Corp., 1140 H. A. Thrush A Co., 1398-1399 Warren Webster A Co., 1437-1441 HEATERS, Fuel Oil United States Radiator Corp., 1344 Western Blower Co., 1255 Airtemp Div., Chrysler Corp., 1126 1345 Westinghouse Electric Corp., Air 1127 Bell A Goesett Co., 1396-1397 York-Shipley, Inc., 1394 Conditioning Div., 1117 L. J. Wing Mfg. Co., 1170-1172 Brown Products Co., 1333 HEATERS, Space, Direct-Fired Young Radiator Co., 1173 Cyclotherm Corp., 1356 Chicago Steel Furnace Co., 1146 JohnZink Co., 1380-1381 Fluid Systems, Inc., 1376-1377 Norge Heat, Div. Borg-Warner Heaters, Storage Corp., 1134-1135 Hook A Ackerman, Ino., 1339 HEATERS, Unit, Electric Electromode Corp., 1152 Arthur A. Olson A Co., 1150 Kewanee Boiler Corp., 1364-1367 Ilg Electric Ventilating Co., 1156, Patteraon-Kelley Co., Inc., The, National Radiator Co., The, 1340 1244 1221 1341 L. J. Wing Mfg. Co., 1170-1172 Ray Oil Burner Co., 1390-1391 Pacific Steel Boiler Div., U. S. Taco Heaters, Inc., 1400 Radiator Corp., 1342-1343 HEATERS, Unit, Gas Fired H. A. Thrush A Co., 1398-1399 Patterson-Kelley -Co., Inc., The, Airtherm Mfg. Co., 1141 York-Shipley, Inc., 1394 1221 American Blower Corp., 1100-1101 United States Radiator Corp., 1344 American Foundry A Furnace Co., HEATERS, Gas Airtherm Mfg. Co., 1141 American Foundry A Furnace Co., 1126-1121 E. K. Campbell Co., 1143 Campbell Heating Co., 1124-1125. 1142 Cyclotherm Corp.,.1356 Dravo Corp., 1144-1145 Hayes Furnace Mfg. A Supply Co., 1128 Hook A Ackerman, 1339 Lee Corp., 1147 L. J. Mueller Furnace Co., 1132-1133 National Heater Co., 1148-1149 Norge Heat, Div. Borg-Warner Corp., 1134-1135 Arthur A. Olson A Co., 1150 Rheem Mfg. Co., 1136 United States Radiator Corp., 1344 1345 . Utility Appliance Corp., 1140 York-Shipley, Inc., 1394 1345 HEATERS, Tank Bell A Gossett Co., 1396-1397 Fluid Systems, Inc., 1376-1377 Hook A Ackerman, Inc., 1339 Pacific Steel Boiler Div., U. .8. Radiator Corp., 1342-1343 Patterson-Kelley Co., Inc., The, 1221 . Spencer Heater, Lycoming-Spencer Div., Avoo Mfg. Corp., 1348-1349 United States'Radiator Corp., 1344 1345 HEATERS. Unit Airtherm Mfg. Co., 1141 American Blower Corp., 1100-1101 Automatic Gas Equipment Co., 1151 Bishop A Babcock Mfg. Co., The, (Massachusetts Blower Div.), 1237 Brown Products Co., 1333 Buffalo Forge Co., 1238. 1120-1121 American. Furnace Co., 1122 Automatic Gas Equipment Co., 1151 Carrier Corp., 1106-1107 Hastings Air Conditioning Co., Inc., 1111 Hayes Furnace Mfg. A Supply Co., 1128 Hg Electric Ventilating Co., 1156, 1244 Lee Corp., 1147 Modine Mfg. Co., 1160-1161 L. J. Mueller Furnace Co., 1132-1133 National Heater Co., 1148-1149 National Radiator Co., The, 1340 1341 Arthur A. Olson A Co., 1150 Rheem Mfg. Co., 1136 . Trane Co., The, 1168-1169 United States Air Conditioning Corp., 1116 Utility Appliance Corp., 1140 L. J. Wing Mfg. Co., 1170-1172 John Zink Co.. 1380-1381 Burnham Corp., 1335 HEATERS, Hot Water Service Air Devices, Inc., 1178, 1263 Airtemp Div., Chrysler Corp., 1126 1127 Aldrich Co., 1332 American Radiator A Standard Sanitary Corp., 1328-1331 Bell A Gossett Co., 1396-1397 . Burnham Corp., 1335 Campbell Heating Co., 1124-1125, 1142 Carrier Corp., 1106-1107 Chicago Steel Furnace Co., 1146 Clarage Fan Co., 1105 Crane Co.. 1336-1337 Dravo Corp., 1144-1145 C. A. Dunham Co., 1415-1419 Electromode Corp., 1152 HEATERS, Unit, Oil Fired Airtherm Mfg. Co., 1141 American Foundry A Furnace Co., 1120-1121 Dravo Corp., 1144-1145 Lee Corp., 1147 National Heater Co., 1148-1149 Arthur A. Olson A Co., 1150 Crane Co., 1336-1337 Cyclotherm Corp., 1356 Dewey-Shepard Boiler Co., 1357 Fedders-Quigan Corp., 1153 Grinnell Co., Inc., 1154-1155 HEATERS, Unit, Turbine Hartzell Propeller Fan Co., Div. of L. J. Wing Mfg. Co., 1170-1172 Dutton Boilers, Div. Hapman- Castle Hills Corp., 1242 Dutton Co., 1358 Hastings Air Conditioning Co., Inc., HEATING SYSTEMS, Air, Hook A Ackerman, Inc., 1339 1111 Heavy Duty S. T. Johnson Co., 1386-1387 Hayes Furnace Mfg. A Supply Co., Airtherm Mfg. Co., 1141 Johnston Bros., Inc., 1363 1128 American Foundry A Furnace Co., Kewanee Boiler Corp., 1364-1367 Hg Electric Ventilating Co., 1156, 1120-1121 L. J. Mueller Furnace Co., 1132-1133 1244 E. K. Campbell Co., 1143 Ptttific Steel Boiler Div., U. 8. Kennard Corp., 1157 Campbell Heating Co., 1124-1125, Radiator Corp., 1342-1343 . Lee Corp., 1147 . 1142 Patterson-Kelley Co., Inc., The, H. C. Little Burner Co., 1385 Chicago Steel Furnace Co., 1148 ' 1221 McCord Corp., 1162 Dravo Corp., 1144-1145 Petroleum Heat A Power Co., 1388 McQuay, Inc., 1158-1159 Electromode Corp., 1152 1389 Modine Mfg. Co., 1160-1161 Lee Corp., 1147 - Please mention THE GUIDE 1952 when writing to Advertisers Index to Modem Equipment 1085 Meyer Furnace Co., The, 1130-1131 McQuay, Inc.. 1158-1159 L. J. Mueller Furnace Co., 1132-1133 Trane Co., The, 1168-1169 United States Radiator Corp., 1344-- 1345 General Electric Co., 1108-1109 Hayes Furnace Mfg. A Supply Co., 1128 National Heater Co., 1148-1149 Vapor Heating Corp., 1369 Hook A Ackerman, Inc., 1339 Niagara Blower Co., 1112 Waterman-Waterbury Co., The, S. T. Johnson Co., 1386-1387 Pacific Steel Boiler Div., U. 8. 1138-1139 Kewanee Boiler Corp., 1364-1367 Radiator Corp., 1342-1343 Weil-McLain Co., 1351 Lee Corp., 1147 Arthur A. Olson A Co., 1150 Ray Oil Burner Co., 1390-1391 Syncromatic Corp., 1129 Trane Co., The, 1168-1169 United States Radiator Corp., 1344 1345 . HEATING SYSTEMS, Air Resi dence 1 Airtemp Div., Chrysler Corp., 1126 1127 HEATING SYSTEMS, Coal-fired Airtemp Div., Chrysler Corp., 1126 1127 American Foundry A Furnace Co., 1120-1121 American Radiator A Standard Sanitary Corp., 1328-1331 E. K. Campbell Co., 1143 Campbell Heating Co., 1124-1125, 1142 Meyer Furnace Co., The, 1130-1131 L. J. Mueller Furnace Co., 1132-1133 National Heater Co., 1148-1149 Norge Heat, Div. Borg-Warner Corp., 1134-1135 Arthur A. Olson A Co., 1150 Pacific Steel Boiler Div., U. S. Ra diator Corp., 1342-1343 Rheem Mfg. Co., 1136 Servel, Inc., 1137 - Syncromatic Corp., 1129 ' American Foundry A Furnace Co., 1120-1121 American Radiator A Standard Sanitary Corp., 1328-1331 Burnham Corp., 1335 Campbell Heating Co., 1124-1125, 1142 Crane Co., 1336-1337 Dravo Corp., 1144-1145 Fitzgibbons Boiler Co., Ine., 1360 1361 Kewanee Boiler Corp., 1364-1367 Lee Corp., 1147 Meyer Furnace Co., The, 1130-1131 United States Air Conditioning Corp., 1116 Utility Appliance Corp., 1140 Waterman-Waterbury Co., The.' 1138-1139 L. J. Wing Mfg. Co., 1170-1172 York-Shipley, Inc., 1394 Chicago Steel Furnace Co., 1146 L. J. Mueller Furnace Co., 1132-1133 Electromode Corp., 1152 National Heater Co., 1148-1149 HEATING SYSTEMS, Genera General Automatic Products Corp., Norge Heat, Div. Borg-Warner tors, Steam 1338 Corp., 1134-1135 . Vapor Heating Corp., 1369 General Electric Co., 1108-1109 Arthur A. Olson A Co.. 1150 Hayes Furnace Mfg. A Supply Co., Syncromatic Corp., 1129 HEATING SYSTEMS, HIgh- 1128 Waterman-Waterbury Co., The, temperatlire Fluid Meyer Furnace Co., The, 1130-1131 1138-1139 Fluid Systems, Ino., 1376-1377 L. J. Mueller Furnace Co., 1132-1133 Titusville Iron Works Co., The, Norge Heat, Div. Borg-Warner Corp., 1134-1135 Padfio Steel Boiler Div., U. S. Radiator Corp., 1342-1343 Ray Oil Burner Co., 1390-1391 Refrigeration Engineering, Inc., 1233 Syncromatic Corp., 1129 HEATING SYSTEMS, Electric Electromode Corp., 1152 . Fluid Systems, Inc., 1376-1377 Ilg Electric Ventilating Co., 1156, 1244 (Div. of Struthere-Wells Carp.), 1368 HEATING SYSTEMS, Hot Water Air Devices, Inc., 1178-1263 Airtemp Div., Chrysler Corp., 1126 1127 . Trane Co., The, 1168-1169 . United States Radiator Corp., 1344 HEATING SYSTEMS, Furnace American Radiator A Standard American Foundry A Furnace Co., Sanitary Corp., 1328-1331 1345 Waterman-Waterbury 1138-1139 Co., 1120-1121 The, American Furnace Co., 1122 Bell A Gossett Co., 1398-1397 Brown Products Co., 1333 American Radiator A Standard Burnham Corp., 1335 York-Shipley, Inc., 1394 Sanitary Corp., 1328-1331 Crane Co., 1336-1337 E. K. Campbell Co., 1143 Durant Insulated Pipe Co., 1453 HEATING SYSTEMS, Auto - matte Airtemp Div., Chrysler Corp., 1126 1127 Airtherm Mfg. Co., 1141 American Foundry A Furnace Co., 1120-1121 'American Radiator A Standard Sanitary Corp., 1328-1331 E. K. Campbell Co., 1143 Campbell Heating Co., 1124-1125, 1142 Chicago Steel Furnace Co., 1146. Crane Co., 1336-1337 Dravo Corp., 1144-1145 C. A. Dunham Co.. 1415-1419 Electromode Corp., 1152 General Automatic Products Corp., 1338 General Electric Co., 1108-1109 Hayes Furnace Mfg. A Supply Co., 1128 Hook A Ackerman, Ino., 1339 S. T. Johnson Co., 1386-1387 Campbell Heating Co., 1124-1125, 1142 Crane Co., 1336-1337 Dravo Corp., 1144-1145 ' General Electric Co., 1108-1109 Hayes Furnace Mfg. A Supply Co., 1128 S. T. Johnson Co., 1386-1387 Lee Corp., 1147 Meyer Furnace Co., The, 1130-1131 L. J. Mueller Furnace Co., 1132-1133 National Heater Co., 1148-1149 Norge Heat, Div. Borg-Warner Carp., 1134-1135 Arthur A. Olson A Co., 1150 Petroleum Heat A Power Co., 1388 1389 Ray Oil Burner Co., 1390-1391 Rheem Mfg. Co.. 1136 Syncromatic Corp., 1129 . united States Radiator Corp., 1344 1345 Waterman-Waterbury Co., The, 1138-1139 General Automatic Products Corp., 1338 General Electric Co., 1108-1109 Hoffman Specialty Go., 1420-1423 Hook A Ackerman, Inc., 1339 S. T. Johnson Co., 1386-1387 Kewanee Boiler Corp., 1364-1367 Kritzer Radiant Coils, Inc., 1222 Jas. P. Marsh Corp., 1428-1429 L. J. Mueller Furnace Co., 1132-1133 Norge Heat, Div. Borg-Warner Corp., 1134-1135 Pacific Steel Boiler Div., U. 8. Ra diator Corp., 1342-1343 Refrigeration Engineering, Inc., 1233 Rio-wiL Co., The, 1455 Sareo Co., Inc., 1434-1435 . Sarcotherm Controls, Inc., 1433 . H. B. Smith Co., Inc., The, 1350 Taco Heaters, Inc., 1400 Trane Co., The, 1168-1169 H. A. Thrush A Co., 1398-1399 United States Air Conditioning Kewanee Boiler Corp., 1364-1367 Corp., 1116 Lee Corp., 1147 Mever Furnace Co., The, 1130-1131 L. J. Mueller Furaaoe Co., 1132-1133 National Heater Co., 1148-1149 HEATING SYSTEMS, Gas-fired Airtemp Div., Chrysler Corp., 1126 1127 Airtherm Mfg. Co., 1141 United States Radiator Corp., 1344 1345 Vapor Heating Corp., 1369 Vulcan Radiator Co., The, 1224 National Radiator Co., The, American Foundry A Furnace Co., Warren Webster A Co., 1437-1441 1340-1341 1120-1121 York-Shipley, Inc., 1394 Norge Heat. Div. Borg-Warner American Furnace Co., 1122 Corp., 1134-1135 American Radiator A Standard HEATING SYSTEMS, Oil Fired Arthur A. Olson A Co., 1150 Sanitary Corp., 1328-1331 Airtemp Div., Chrysler Corp., 1126 Pacific Steel Boiler Div., U. S. E. K. Campbell Co., 1143 1127 Radiator Corp., 1342-1343 . Campbell Heating Co., 1124-1125, Airtherm Mfg. Co., 1141 Petroleum Heat A Power Co., 1388 1142 American Foundry A Furnace Co., 1389 Chicago Steel Furnace Co., 1146 1120-1121 Ray Oil Burner Co., 1390-1391 Crane Co., 1336-1337 American Furnace Co., 1122 C. L. Rayfield Co., 1392 Dewey-Shepard Boiler Co., 1357 American Radiator A Standard Rheem Mfg. Co., 1136 Dravo Corp., 1144-1145 Sanitary Corp., 1328-1331 Sareo Co.. Inc., 1434-1435 Fitzgibbons Boiler Co., Inc., 1360-- Brown Products Co., 1333 Sarcotherm Controls, Inc., 1433 1361 E. K. Campbell Co., 1143 Numerals following Manufacturers' Names refer to pages in the Catalog Data Section 1086 1952 Guide Campbell Beating Co., 1124-1125, Barnes A Jones, Inc., 1409 HUMIDITY AND TEMPERA 1142 C. A. Dunham Co., 1415-1419 TURE CONTROL Chicago Steel Furnace Co., 1146 General Electric Co., 1108-1109 ' American Moistening Co., 1214 Crane Co.. 1336-1337 Hoffman Specialty Co., 1420-1423 Armstrong Machine Works, 1412 Dewey-Shepard Boiler Co., 1357 Illinois Engineering Co., 1424-1425 1413 Dravo Corp., 1144-1145 Kewanee Boiler Corp., 1364-1367 Bahnson Co., The, 1102-1103 Fit*gibbons Boiler Co., Inc., 1360- Jas. P. Marsh Corp., 1428-1429 Barber-Colman Co.,-1269 1361 Saroo Co.. Inc., 1434-1435 Buensod-Staoey, Inc., 1104 General Automatic Products Corp., Trane Co., The. 1168-1169 C. A. Dunham Co., 1415-1419 - 1338 Vapor Beating Corp., 1369 Johnson Service Co., 1312-1313 General Electric Co., 1108-1109 Warren Webster A Co.. 1437-1441 Mario Cod Co.. 1229 S. T. Johnson Co., 1386-1387 York-Shipley. Inc., 1394 Minneapolis-Honeywell Regulator Kewanee Boiler Corp., 1364-1367 Co., 1316-1317 Lee Corp., 1147 . H. C. little Burner Co., 1385 Meyer Fiirnaoe Co.. The, 1130-1131 HOSE, Flexible Metal American Brass Co., The,. 1174-1175 Chicago Metal Hose'Div..' Flexonica Parks-Cramer Co., 1114-1115 Perm Controls, Inc., 1319 Powers Regulator Co., 1321 ' L. J. Mueller Furnace Co., 1132-1133 nnm ma Ready-Power Co., The, 1231 National Beater Co., 1148-1149 Taylor Instrument Cos., 1326 NnSL *n?uii<SIV' Borg'Warner HOT WATER HEATING SYS- Corp., 1134-1135 Arthur A. Olson A Co., 1150 Pacific Steel Boiler Div., U. S. TEMS (See Heating Systems, Hot Water) ' HUMIDITY RECORDERS and INDICATORS American Moistening Co., 1214 Radiator Corp., 1342-1343 Johnson Service Co.; 1312-1313 Ray Oil Burner Co., 1890-1391 HUMIDIFIERS Minneapolis-Honeywell Regulator C. L. Rayfield Co.. 1392 Serve! Inc., 1137 Air A Refrigeration Corp., 1099 American Moistening Co., 1214 Co., 1316-1317 Moeller Instrument Co., 1318 Syncromatic Corp., 1129 Armstrong Machine Works, 1412 Parks-Cramer Co., 1114-1115 _ United States Radiator Corp., 1344 1413 Powers Regulator Co., 1321 1345 Bahnson Co.., The,. 1102-1103 Taylor Instrument Cos., 1326 Waterman-Waterbury Co., The, Biliks Mfg. Co., 1206-1207 1138-1139 Buensod-Staoey, Inc., 1104 Williams Oil-O-Matic Div., Eureka Buffalo Forge Co., 1238 Williams Corp., 1393 Carrier Corp., 1106-1107 Farr Co., 1196-1197 HYGROMETERS (See Humidity Recorder and Indicator) American Moistening Co., 1214 Minneapolis-Honeywell Regulator HEATING SYSTEMS. Steam Co., 1316-1317 AWemp Div., Chxyalec Corp.. 1126- }>& Moeller Instrument Co., 1318 Parks-Cramer Co., 1114-1115 American Radiator * Standard Sanitary Corp., 1328-1331 Barnes A Jones, Inc., 1409 Burnham Corp., 1335 Crane Co., 1336-1337 Dewey-Shepard Boiler Co.. 1357 C. A. Dunham Co., 1415-1419 McDonnell A Miller, Inc., 1372-1375 Meyer Furnace Co., The, 1130-1131 L. J. Mueller Furnace Co., 1132-1133 Niagara Blower Co., 1112 Parks-Cramer Co., 1114-1115 Re_fr_igeration Engineering, Inc., Taylor Instrument Cos., 1326 IGNITION. Oil Burner (See Trans/ormert) INDUCED DRAFT COOLING TOWERS (See Cooling Towers, FDiutzrgaibnbt oInnssuUBlaomtieliepd*r rUPvoip.e, TinCnceo...,, nIS1wf4iO53-- Tnm. nJe. QSC_o_om_e,,rs*ioInnnc_.i<1,1>16m28U-1v1"6l*9UI Forced Draft, Mechanical Draft) Acme Industries, Ine., 1216 1361 General Electrie Co., 1108-1109 Hoffman Specialty Co., 1420-1423 Illinois Engineering Co., 1424-1425 S. T. Johnson Co., 1386-1387 Kewanee Boiler Corp., 1364-1367 Kritser Radiant Coils, Inc., 1222 Jas. P. Marsh Corp., 1428-1429 L. J. Mueller Furnace Co., 1132-1133 Pacific Steel Boiler Div., U. .8. Radiator Corp., 1342-1343 Refrigeration Engineering, Inc., 1233 HUMIDIFIERS, Central Plant Air A Refrigeration Corp., 1099 American Moistening Co., 1214 Bahnson Co., The, 1102-1103 Barber-Colman Co., 1269 B...u..e..n...sod-Stacey, Inc.,. 1104 Buffalo Forge Co., 1238 Carrier Corp., 1106-1107 Farr Co., 1196-1197 Johnson Service Co., 1312-1313 Baker Refrigeration Corp., 1225 Baltimore Aircoil Co., Inc., 1228 Binks Mfg. Co., 1206-1207 Fluor Corp., Ltd., The, 1208 . Foster Wheeler Corp., 1209 Kennard Corp., 1157 '___ Lilie-Hoffmann Cooling Towers, Inc., 1210 Mario Coil Co., 1229 J. F. Pritchard A Co., 1212 Water Cooling Equipment Co., 1213 Ric-wiL Co., The, 1455 Saroo Co., Inc., 1434-1435 H. B. Smith Co., Inc., The. 1350 Trane Co., The, 1168-1169 Mario Coil Co., 1229 Jas. P; Marsh Corp., 1428-1429 McDonnell A Miller, Inc., 1372-1375 Niagara Blower Co., 1112 INSERTS. Concrete Carty A Moore Engineering Co., 1414 . United States Air Conditioning Corp., 1116 United States Radiator Corp., 1344- 1345 Vapor Heating Corp., 1369 Vulcan Radiator Co., The, 1224 Warren Webster & Co., 1437-1441 L. J. Wing Mfg. Co., 1170-1172 York-Shipley, Inc., 1394 Parks-Cramer Co., 1114-1115 Powers Regulator Co., The, 1321 Trane Co., The, 1168-1169 Westinghouse Electric Corp., Stur- tevant Div., 1204, 1256 HUMIDIFIERS, Convector -M-a-id---O.'.-.M....i.s.t, -Inc., -1-4--2-6---1--4-2--7 INSTRUMENTS, Indicating, Controlling and Recording Barber-Colman Co., 1269 Combusion Control Corp., 1301 Electric Auto-Lite Co., The, In strument A Gauge Div., 1303 Illinois Testing Laboratories, Inc., 1311 Johnson Service Co., 1312-1313 ,, HUMIDIFIERS, Industrial HEATING SYSTEMS, Vacuum Maid-O'-Mist. Inc., 1426-1427 Airtemp Div., Chrysler Corp., 1126 1127 American Radiator A Standard Sanitary Corp., 1328-1331 Maid-O'-Mist. Inc., 1426-1427 Barnes A Jones, Inc., 1409 ' C. A. Dunham Co., 1415-1419 HUMIDIFIERS, Unit General Electric Co., 1108-1109 Armstrong Machine Works, 1412 Jas. P. Marsh Corp., 1428-1429 Minneapolis-Honeywell Regulator Co., 1316-1317 Moeller Instrument Co., 1318 Perfex Corp., 1320 Powers Regulator Co., The, 1321 Rochester Mfg. Co., 1322 Taylor Instrument Cos., 1326 Hoffman Specialty Co., 1420-1423 Kewanee Boiler Corp., 1364-1367 Jas. P. Marsh Corp., 1428-1429 Sarco Co., Inc., 1434-1435 Warren Webster A Co., 1437-1441 1413 Bahnson Co., The, 1102-1103 Buffalo Forge Co., 1238 Mario Coil Co.. 1229 D. J. Murray Mfg. Co., 1163 Niagara Blower Co., 1112 HEATING SYSTEMS, Vapor P__a_r_k_s_-_C__ra__m_e__r_C_o_., 1.114-1.115 Airtemp Div., Chrysler Corp., 1126- Refrigeration Engineering, INSULATION. Acoustical {See Insulation, Sound Deadening) Inc., INSULATION. Aluminum Infra Insulation, Inc., 1482 Reflectal Corp., 1483 Silvercote Products, Inc., 1484 1127 1233 American Radiator. A Standard H. J. Somers, Ine., 1200-1201 Sanitary Corp., 1328-1331 Trane Co., The, 1168-1169 INSULATION, Asbestos (See Cov ering, Pipe) Please mention THE GUIDE 1952 when writing to Advertisers Index to Modem Equipment 1087 INSULATION. Building Owens-Coming Fiberglas Corp., INSULATION, Steel American Flange A Mfg. Co., Inc., 1451 American Flange A Mfg. Co~ Ine.: . 1480 Pacific Lumber Co., The, 1478 1480 American Structural Products Co., Sprayo-Flake Insulation Co., 1478 Sprayo-Flake Insulation Co., 1476 Sub. of Owens-Illinois Glass Co., 1477 1477 1460 Grant Wilson, Inc., 1452 Armstrong Cork Co., 1464 - . Wood Conversion Co., 1479 INSULATION, Structural Philip Carey Mfg. Co., The, 1448 American Flange A Mfg. Co.. Inc.. 1449 INSULATION, Magnesia 1480 Celotex Corp., The, 1466 Gustin-Bacon Mfg. Co., 1450 * Infra Insulation, Ine., 1482 - Philip Carey Mfg. Col, The, 1448 Armstrong Cork Co. (Building Ma 1449 * terials Div.), 1464 ' Johns-Manvflle, 1470-1471 Celotex Corp.. The, 1466 Insul-Mastic Corp. of America, 1467 Insulite, 1468-1469 Johns-ManviUe. 1470-1471 Mundet Cork Corp., 1465 Grant Wilson, Inc., 1452 Insul-Mastic Corp. of Amau'wi 1467 Insulite, 1468-1469 Johns-Manville, 1470-1471 Kimberly-Clark Corp., 1472-1473 Lockport Cotton Batting Co., 1474 Mundet Cork Corp., 1465 Owens-Coming Fiberglas Corp., 1451 Owens-Illinois Glass Co., Kaylo - Div., 1475 Pacific Lumber Co., The, 1478 Pittsburgh Corning Corp., 1462 INSULATION, Metal American Flange A Mfg. Co., Inc., 1480 Infra Insulation, Ino., 1482 Reflectal Corp., 1483 Silvercote Products, Inc., 1484 Sprayo-Flake Insulation Co., 1476 1477 1463 H. W. Porter A Co.. Inc., 1454 INSULATION, Mineral Reflectal Corp., 1483 Insul-Mastic Cam. of America, 1467 Silvercote Products. Inc.. 1484 Owens-Illinois Glass Co., Kaylo Sprayo-Flake Insulation Co., 1476 Div., 1475 1477 Sprayo-Flake Insulation Co., 1476 Grant Wilson, Inc., 1452 1477 Wood Conversion Co., 1479 Z-Crete Div., Zonolife Co., 1458 Owens-Illinois Glass Co., Kaylo Div., 1475 Pittsburgh Corning Corp., 1462-1463 Wood Conversion Co., 1479 Zonolite Co., 1458 - -INSULATION, Underground Steam Pipe Durant Insulated Pipe Co., 1453 Insul-Mastic Corp. of Amm-foa, 1497 Johns-Manvflle, 1470-1471 Owens-Coming Fiberglas Com.. 1451 ^ Owens-Illinois Glass Co., Kaylo Div., 1475 H. W. Porter & Co., Ino., 1454 Rio-wiL Co., The, 1455 ' INSULATION, Calcium Silicate Johns-Manville. 1470-1471 Owens-Illinois Glass Co., Kaylo Div., 1475 INSULATION. Mineral Wool (See Insulation, Building) INSULATION, Pipes and Sur Union Asbestos A Rubber Co.. 1456-1457 Grant Wilson, Inc., 1452 . Z-Crete Div., Zonolite Co., 1458 INSULATION, Cellular Glass Armstrong Cork Co., 1464 faces (See Covering, Pips and INSULATION, Water . Surface) ' - April 8howere Co., Inc., 1459 Pittsburgh Corning Corp., 1462-1463 INSULATION, Cork Armstrong Cork Co., 1464 Insul-Mastic Corp. of America, 1467 Mundet Cork Corp., 1465 ' INSULATION. Plastic Insul-Mastic Corp. of America, 1467 Sprayo-Flake Insulation Co., 1475 1477 JOINTS, EXPANSION (See Ex pansion Joints) LABORATORY, RESEARCH AND TESTING (See Testing H. W. Porter A Co., Ine., 1454 INSULATION, Reflective Laboratory) * Grant Wilson, Inc., 1452 American Flange A Mfg. Co., Inc., 1480 LIMB SCALE CONTROL INSULATION, Cotton Lockport Cotton Batting Co., 1474 INSULATION, Ducts, Ventilat ing, Air Conditioning Armstrong Cork Co., 1464 ' Philip Carey Mfg. Co., The, 1448 1449 Celotex Corp., The, 1466 Infra Insulation, Inc., 1482 Kimberly-Clark Corp.. 1472-1473 Lockport Cotton Batting Co., 1474 Reflectal Corp., 1483 Silvercote Products, Inc., 1484 Sprayo-Flake Insolation Co., 1476 1477 . Vinco Co., Inc., The, 1370-1371 LIQUID LEVEL CONTROLS Alco Valve Co., 1299 Barber-Colman Co., 1269 General Controls, 1306-1307 Johnson Service Co., 1312-1313 Jas. P. Marsh Corp., 1428-1429 Celotex Corp., The, 1466 Gustin-Bacon Mfg. Co., 1450 INSULATION, Refractory McDonnell A Miller, Ino., 1372-1375 Minneapolis-Honeywell Regulator Infra Insulation, Inc., 1482 Armstrong Cork Co., 1464 Co., 1316-1317 Insul-Mastic Corp. of America, 1467 Philip Carey Mfg. Co., The. 1448 Penn Controls, Inc., 1319 Johns-Manville, 1470-1471 1449 Photoswitch Inc., (Affiliate of Com Kimberly-Clark Corp., 1473-1473 Johns-Manvflle. 1470-1471 Lockport Cotton Batting Co., 1474 Grant Wilson, Ine., 1452 bustion Control Corp.), 1301 Powers Regulator Co., The, 1321 ' Mundet Cork Corp., 1465 Saroo Co., Inc., 1434-1435 Owens-Coming Fiberglas Corp., INSULATION, Sheets, Stainless Spence Engineering Co., Inc., 1324 Steel Taylor Instrument Cos., 1328 Owen-Illinois Glass Co., Kaylo American Flange A Mfg. Co., 1480 Div., 1475 LIQUID LEVEL GAGES (See Pittsburgh Coming Corp., 1462-1463 Reflectal Corp., 1483 Sprayo-Flake Insulation Co., 1476 1477 Grant Wilson, Inc.,-1452 Wood Conversion Co., 1479 INSULATION, Sound Deaden* tng (Sea also Felt, Sound Deaden ing) . Armstrong Cork Qx, 1464 Celotex Corp., The, 1466 Gustin-Bacon Mfg. Co., 1450 Gages, Liquid Level) LOUVERS (Alto see Grilles, Reg isters) American Foundry A Furnace Co 1120-1121 INSULATION, Felt Johns-ManviUe. 1470-1471 Kimberly-Clark Corp., 1473-1473 Lockport Cotton Batting Co.-, 1474 Insul-Mastic Corp. of America, 1467 Insulite, 1468-1469 . Johns-Manvflle, 1470-1471 Kimberly-Clark Corp., 1472-1473 Lockport Cotton Batting Co., 1474 Auer Register Co., The, 1288 Barber-Colman Co., 1269 Diamond Mfg. Co., 1273 Dole Valve Co., The, 1443 General Blower Co., 1241 ' Owens-Coming Fiberglas 1451 Grant Wilson, Inc., 1452 Wood Conversion Co., 1479 Corp., Mundet Cork Corp., 1465 Owens-Coming Fiberglas Corp., 1451 Pacific Lumber Co., The, 1478* Hart A Cooley Mfg. Co., 1274-1275 Hendrick Mfg. Co., 1276-1277 Independent Register Co., The, 1278 Minneapolis-Honeywell Regulator Sprayo-Flake Insulation Co., 1476 Co., 1316-1317 INSULATION. Fiber Celotex Corp., The, 1466 1477 Pyle-National Co., The, (Multi Union Asbestos & Rubber Co., 1456 Vent Div.), 1280-1281 Gustin-Bacon Mfg., Co., 1450 1457 Register A Grille Mfg. Co., Ino., Insulite. 1468-1469 Grant Wilson, Ine., 1452 1279 . Kimberly-Clark Corp., 1472-1473 Wood Conversion Co., 1479 Standard Stamping A Perforating Lockport Cotton Batting Co., 1474 - Zonolite Co., 1458 Co.. 1282 Numerals following Manufacturers* Names refer to pages In the Catalog Data Section 1088 1952 Guide Stewart Mfg. Co., Inc., 1283 - Swartwout Co., The, 1261 Titus Mfg. Carp., 1284-1285 Tuttle A Bailey, Inc., 1286-1287 United States Register Co., 1288 1289 L. J. Wing Mlg. Co., 1170-1172 MECHANICAL DRAFT APPA RATUS (Sea Blowers, Forced Draft) General Blower Co., 1241 Weatinghouae Electric Corp., Stur- tevant Div., 1204, 1256 MECHANICAL DRAFT COOL ING TOWERS (See Coding Towers, Forced Draft, Induced Draft) Acme Industries, Inc., 1216 Baker Refrigeration Corp., 1225 Baltimore Alrooil Co., Inc., 1226 Binks Mfg. Co., 1206-1207 Fluor Coro., Ltd., The, 1208 . Kannard Corp., 1157 Lilie-Hoffmann Cooling Towers, Inc., 1210 Mario Coil Co., 1229 J. F. Pritchard k Co., 1212 Water Coding Equipment Co., 1213 METAL INSULATION (See In sulation, Metal) METERS, Air Anemoetat Corp. of America, 1286 1267 Illinois Testing Laboratories, Inc., 1311 Minneapolis-HoneyweU Regulator Co., 1316-1317 Automatic Burner Corp., 1383 Bryan Steam Corp., 1334 Clover-Brooks Co., 1353' Webster Engineering Co., The, 1379 York-Shipley, Ino., 1394 Enterprise Engine A Machinery Co., Burner Div., Sub. of General Metals Corp., 1384 Ray Oil Burner Co., 1390-1391 York-Shipley, Inc., 1394 OIL BURNERS, Vaporizing' American Furnace Go., 1122 . Automatic Burner Corp., 1383 H. C. Little Burner Co., 1385 York-Shipley, Inc., 1394 ` OIL BURNERS, Automatic OIL BURNERS, Variable Capac Ace Engineering Co., 1382 - ity Aldrich Co., 1332 Enterprise Engine A Machinery Airtemp Div., Chrysler Corp., 1126-- Co., Burner Div., Sub. of General 1127 Metals Coro., 1384 ' American Radiator A Standard C. L. Rayfield Co., 1392 Sanitary Corp., 1328-1331 York-Shipley, Inc., 1394 Automatic Burner Corp., 1383 Cleaver-Brooks Co., 1353 Enterprise Engine A Machinery OIL BURNING EQUIPMENT Ace Engineering Co.', 1382 Co., Burner Div., Sub. of General Metals Corp., 1384 General Automatic Products Corp.. 8 1338 . T. Johnson Co., 1386-1387 Johnston Bros., Inc., 1363 H. C. Little Burner Co., 1385 L. J. Mueller Furnace Co., 1132-1133 Norge Heat, Div. Borg-Wamer Corp., 1134-1135 Aldrich Co., 1332 Automatic Burner Corp., 1383 . Brown Products Co., 1333 Enterprise Engine A Machinery Co., Burner Div., Sub. of General Metals Corp., 1384 ' Fluid Systems, Inc., 1376-1377 General Automatic Products Coro.. 1338 General Electric Co., 1108-1109 ' Pacific Steel Boiler Div., U. S. Radiator Corp., 1342-1343 Petroleum Heat A Power Co., 1388 1389 Ray Oil Burner Co., 1390-1391 C. L. Bayfield Co., 1392 United States Radiator Corp., 1344 1345 Webster Engineering Co., The, 1379. Willjams Ou-O-MatJo Div., Eureka Williams Corp., 1393 H. C. Little Burner Co., 1385 Meyer Furnace Co., The, 1130-1131 L. J. Mueller Furnace Co., 1132-1133 National Radiator Co., The, 1340 1341 Petroleum Heat A Power Co., 1388- 1389 Ray Oil Burner Co., 1390-1391 C. L. Rayfield Co., 1392 Webster Engineering Co., The, 1379 York-Shipley, Inc., 1394 . York-Shipley, Inc., 1394 METERS, Flow Minneapolis-HoneyweU Regulator Co., 1316-1317 Taylor Instrument Coe., 1326 OIL BURNERS, Pressure Atom izing Airtemp Div., Chrysler Caro., 1128 1127 OIL BURNING SYSTEMS In dustrial Ace Engineering Co., 1382 Enterprise Engine A Machinery Co., Burner Div., Sub. of General Aldrich Co., 1332 Metals Corp., 1384 METERS, Steam Minneapolis-Honeywell Co., 1316-1317 Regulator American Furnace Co., 1122 S. T. Johnson Co., 1386-1387 Automatic Burner Corp., 1383 -Petroleum Heat A Power Co., 1388- * Babcock A Wilcox Co., The, 1352 1389 . Burnham Corp., 1335 Ray Oil Burner Co., 1390-1391 MIXERS, Hot,' Gold Water Fulton Sylphon Div., The, Robert- sbaw-Fulton Controls Co., 1304 1305 Cleaver-Brooks Co., 1353 Crane Co., 1336-1337 Enterprise Engine A Machinery Co., Burner Div., Sub. of General Metals Corp., 1384 York-Shipley, Inc., 1394 OIL TANK GAGES (See Gages, Tank) MOTORS, Damper Minneapolia-Honeywell Regulator Co., 1316-1317 Penn Controls, Inc., 1319 MOTORS, Electric Wagner Electric Corp., 1257 NOISE ELIMINATORS (See Tubinn. Flexible; Sound Deadeners; Vibration Absorbers) NOZZLES, Air Diffusion, Air Washing, Brine Spraying, Hu midifying, Oil Burner, Water Cooling (See Spray Nozzles) General Automatic Products Carp., 8 1338 . T. Johnson Co., 1386-1387 L. J. Mueller Furnace Co., 1132-1133 Pacific Steel Boiler Div., U. 8. Radiator Corp., 1342-1343 Petroleum Heat A Power Co., 1388 1389 Ray OH Burner Co., 1396-1391 C. L. Rayfield Co., 1392 Syncromatic Corp., 1129 United States Radiator Corp., 1344 1345 Williams OH-O-Matic Div., Eureka Williams Corp., 1393 York-Shipley, Lie., 1394 John Zink Co., 1380-1381 ORIFICES, Radiator C. A. Dunham Co., 1415-1419 Illinois Engineering Co., 1424-1425 Johnson Service Co., 1312-1313 Minneapolis-Honeywell Regulator Co., 1316-1317 Sarco Co., Inc., 1434-1435 Sarootherm Controls, Inc., 1433 Warren Webster A Co., 1437-1441 ORNAMENTAL GRILLES (See Deflection Grilles, Grilles, Registers and Ornamental Metal Work, Lou vers, Registers). PANEL HEATING American Radiator A Standard NOZZLES, Oil Burner Automatic Burner Corp., 1383 Monarch Mfg. Works, Inc., 1215 OIL BURNERS, Rotary Ace Engineering Co., 1382 . Enterprise Engine A Machinery Co., . Burner Div., Sub. of General Sanitary Corp., 1328-1331 Crane Co., 1336-1337 Kritzer Radiant CoQs, Inc., 1222 Sarcotherm Controls, Inc., 1433 OIL BURNER MOTORS (See Motors, Electric) OIL BURNER TUBING, Flex ible (See Tufrinp, Flexible, Me tallic) 8 Metals Corp., 1384 . T. Johnson Co., 1386-1387 Johnston Bros., Inc., 1363 Petroleum Heat A Power Co., 1388 1389 Ray Oil Burner Co., 1390-1391 C. L. Rayfield Co., 1392 PANELS. Air Distributing - Pyle-National Co., The. (Multi Vent Div.), 1280-1281 PERFORATED METALS Diamond Mfg. Co., 1273 OIL BURNERS Aldrich Co., 1332 American Radiator A Standard Sanitary Carp., 1328-1331 York-Shipley, Inc., 1394 OIL BURNERS, Steam Atomiz ing Babcock A Wilcox Co., The, 1352 Hendrick Mfg. Co., 1276-1277 Pyle-National Co., The, (Multi Vent Div.), 1280-1281 Register A Grille Mfg. Co., Inc., 1279 Please mention THE GUIDE 1952 when writing to Advertisers Index to Modem Equipment 1089 Standard Stamping A Perforating PLASTER BASE, Sound Dead- Chicago Pump Co., 1403 Co., 1 enlng Crane Co., 1336-1337 Celotex Corp., The, 1466 C. A. Dunham Co., 1415-1419 PILLOW BLOCKS Lau Blower Co., The, 1248 Insulite, 1468-1469 Wood Conversion Co., 1479 ZonoUte Co., 1458 Dutton BoUers, Div. HapmanDutton Co., 1358 . Hoffman Specialty Co., 1420-1423 PILOTS, Safety General Controls, 1306-1307 Milwaukee Gas Specialty Co., 1315 Minneapolia-Honeywell Regulator Co., 1316-1317 Penn Controls, Inc., 1319 ' Perfex Corp., 1320 PIPE ANCHORS PLATES, Stainless Steel United States Steel, 1292 ' PLATES, Steel United States Steel, 1292 PRECIPITATING EQUIPMENT Trion, Inc., 1202 IngeraoU-Rand, 1404 Nash Engineering Co., .The, 1406 1407 Peerless Pump Div., Food Ma chinery A Chemical Corp., 1405 Skidmore Corp., 1408 Spence Engineering Co., Inc., 1324 Worthington Pump A Machinery Corp-. 1118 GrinneU Co., Inc., 1154-1155 Westinghouse Electric Corp., Stur- PUMPS, Brine tevant Div., 1204, 1256 Aurora Pump Co., 1401 PIPE BENDING Buffalo Pumps, Ino., 1402 Acme Industries, Inc., 1216 . PREHEATERS, Fuel CHI Chicago Pump Co., 1403 GrinneU Co.. Inc., 1154-1155 Ace Engineering Co., 1382 Ingersoll-Rand, 1404 Parks-Cramer Co., 1114-1115 Bell A Gossett Co.. 1396-1397 Peerless Pump Div., Food Ma Fluid Systems, Inc., 1376-1377 chinery A Chemical Corp., 1405 PIPE, Brass Taco Heaters, Inc., 1400 American Brass Co., The, 1174-1175 Western Blower Co., 1255 Worthington Pump A Machinery Corp., 1118 Revere Copper A Brass, Inc., 1177 PRESSURE REDUCING PUMPS, Centrifugal PIPE CONDUITS (See Conduits, Underground Pipe) VALVES (See Regulators, Pres Aurora Pump Co., 1401 sure) ' Bell A Gossett Co., 1396-1397 Buffalo Pumps, Inc., 1402 PIPE, Copper American Brass Co., The, 1174-1175 Revere Copper A Brass, Inc., 1177 PIPE COVERING (See Covering, PROCESS HEATING UNITS Air Devices, Inc., 1178, 1263 Niagara Blower Co., 1112 Trane Co., The, 1168-1169 L. J. Wing Mfg. Co., 1170-1172 . Chicago Pump Co., 1403 C. A. Dunham Co., 1415-1419 IngeraoU-Rand, 1404 Peerless Pump Div,, Food Ma chinery A Chemical Corp., 1405 Skidmore Corp., 1408 Pipe) PIPE, Fabricated . Dutton Bailera, Div. Dutton Co., 1358 Hapman- PROCESS HEATING UNITS, Fluid Heating and Cooling Arthur A. Olson A Co., 1150 Trane Co., The. 1168-1169 Taco Heaters, Inc., 1400 Trane Co., The, 1168-1169 Worthington Pump A Machinery Corp*. U18 GrinneU Co., Inc., 1154-1155 PUMPS, Circulating (See Cir PRODUCT DEVELOPMENT culators) PIPE FITTINGS (See Fittings, Pipe) PIPE, FURNACES (See Furnace - Pipe) PIPE HANGERS (See Hangers, Pipe) ^ PIPE HEATING Fluid Systems, Inc., 1376-1377 PIPE, Returns GrinneU Co., Inc., 1154-1155 United States Testing Co., Inc., 1485 PROPELLER FANS (See Fans, Propeller) PSYCHROMBTERS (See Air Measuring, Indicating and Re cording Instruments) American Moistening Co., 1214 ' Bahnson Co., The, 1102-1103 Illinois Testing Laboratories, Inc., 1311 Johnson Service Co., 1312-1313 Minneapolis-HoneyweU Regulator Co., 1316-1317 Aurora Pump Co., 1401 Bell A Gossett Co., 1396-1397 Buffalo Pumps, Inc., 1402 Chicago Pump Co., 1403 In^ersoU-Rand, 1404 Minneapolis-Honeywell Regulator Co., 1316-1317 Peerless Pump Div., Food Ma chinery A Chemical Carp., 1405 Sarcotherm Controls, Inc., 1433 Taco Heaters, Inc., 1400 H. A. Thrush A Co., 1398-1399 Trane Co., The. 1168-1169 Worthington Pump and Machinery Corp., 1118 MoeUer Instrument Co., 1318 PIPE, Spiral Welded Parks-Cramer Co., 1114-1115 Taylor Forge A Pipe Works, 1297 Taylor Instrument Cos., 1326 PUMPS, Condensation Aurora Pump Co., 1401 Buffalo Pumps, Inc., 1402 . . PIPE, Steel Farrar A Trefts, Inc., 1359 GrinneU Co., Inc., 1154-1155 Taylor Forge A Pipe Works, 1297 PIPE SUPPORTS, For Under ground Conduits Durant Insulated Pipe Co., 1453 H. W. Porter A Co., Inc., 1454 Ric-wiL Co., The, 1455 Z-Crete Div., Zonolite Co., 1458 PUBLICATIONS American Artisan, 1490 American Society of Refrigerating Engineers, 1486 Coal-Heat, 1487 Domestic Engineering, 1488 Heating A Plumbing Equipment IfewB 1489 1 Heating A Ventilating, 1489 Heating, Piping and Air Condition ing, 1490 Humbing and Heating Journal, 1491 Chicago Pump Co., 1403 Crane Co., 1336-1337 C. A. Dunham Co., 1415-1419 Hoffman Specialty Co., 1420-1423 IngeraoU-Rand, 1404 Nash Engineering Co., The, 1406 1407 Peerless Pump Div.. Food Ma chinery A Chemical Carp., 1405 Skidmore Corp., 1408 Sterling, Inc., 1325 H. A. Thrush A Co., 1398-1399 Trane Co., The. 1168-1169 8PITOT TUBES (See Air Measuring Sheet Metal Worker, 1491 and Recording Instruments) nips Magazine, 1492 PUMPS, Fuel OH Ace Engineering Co., 1382 ' PLASTER BASE, Fire Retarding PUMP MOTORS Celotex Corp., The, 1466 Electric) (See Motors, Petroleum Heat A Power Co., 1388 1389 PropeUair Div,, Robbins A Myers, Johns-ManviUe, 1470-1471 Inc., 1251 Zonolite Co., 1458 PUMPS, Ammonia Ray Oil Burner Co., 1390-1391 Worthington Pump A Machinery PLASTER BASE, Insulatlve Celotex Corp., The, 1466 Corp., 1118 York Corp, 1119 PUMPS, Sump Aurora Pump Co., 1401 Insulite. 1468-1469 Buffalo Pumps, Inc., 1402 Johns-ManviUe, 1470-1471 PUMPS, Boiler Feed Chicago Pump Co., 1403 Wood Conversion Co., 1479 . Aurora Pump Co., 1401 Peerless Pump Div., Food Ma ZonoUte Co., 1458 Buffalo Pumps, Ino., 1402 chinery A Chemical Carp., 1405 Numerals following Manufacturers* Names refer to pages in the Catalog Data Section 1090 1952 Guide --Propellair Div.. Bobbins A Myers. Inc., 1251 . Skidmore Carp., 1408 PUMPS, Turbine Aurora Pump Co., 1401 Shaw-Perkins Mfg. Co., 1347 . United States Radiator Corp., 1344- 1545 . . Vulcan Radiator Co.. The, 1224 Warren Webster A Co., 1437-1441 National Radmtnr Co.. The, 1340- 1341 * Shaw-Perkins Mfg. Co., 1347 Warren Webster A Co., 1437-1441 Young Radiator Co., 1173 . Chicago Pump Co., 1403 Peerless Pump Div., Food Ma chinery A Chemical Carp.. 1405 Skidmore Corp., 1408 RADIATION, Cast-Iron RANGES. Cooking, Hotel, Hos American Radiator A Standard pital, etc. Sanitary Corp., 1328-1331 Air Devices, Inc., 1178, 1263 Burnham Corp., 1335 - Ray Oil Burner Co., 1390-1391 PUMPS, Turbine Vane Type Peerless Pump Div., Food Ma chinery A Chemical Corp., 1405 PUMPS, Vacuum Crane Co., 1336-1337 D. J. Murray Mfg. Co., 1163 United States Radiator Corp., 1344 1345 Weil-McLain Co., 1351 RECEIVERS, Air Curtis Refrigerating of Curtis Mfg. Co., 1227 Farrar A Trefts, Inc., 1359 Div., Chicago Pump Co., 1403 C. A. Dunham Co., 1415-1410 Hoffman Specialty Co., 1420-1423 Joy Mfg. Co., 1246-1247 Nash Engineering Co., The, 1406 1407 Skidmore Corp., 1408 Sterling, Inc., 1325 Worthington Pump A Machinery Corp., 1118 PUMPS, Water Supply Peerless Pump Div., Food Ma RADIATION, Copper Airtherm Mfg. Co., 1141 C. A. Dunham Co.. 1415-1419 Fedders-Quigan Corp., 1153 GAO Mfg. Co., The, 1220 International Boiler Works CoThe, 1362 Joy Mfg. Co., 1246-1247 ` Worthington Pump A Machinery . Corp., 1118 Kritzer Radiant Coils, Inc., 1222 Modine Mfg. Co., 1160-1161 Rome-Turney Radiator Co., The,' 1223 Shaw-Perkins Mfg. Co., 1347 Trane Co., The, 1168-1169 Young Radiator Co., 1173 . RECEIVERS, Condensation Aurora Pump Co., 1401 . Hoffman Specialty Co., 1420-1423 - Illinois Engineering Co., 1424-1425 Worthington Pump A Machinery Corp., 1118 chinery A Chemical Corp., 1405 RADIATION, Plain and Ex RECEIVERS, Refrigerants PURGERS, Refrigeration tended Surface Acme Industries, Inc., 1216 Armstrong Machine Works, 1412 C. A. Dunham Co., 1415-1419 Worthington Pump A Machinery 1413 Fedders-Quigan Coip., 1153 Corp., 1118 York Corp., 1119 GAO Mfg. Co., The. 1220 York Corp., 1119 . Infra Insulation, Inc., 1482 PURIFIERS AND SCRUBBERS, Kritzer Radiant Cods, Inc., 1222 Air, Gas and Steam . Modine Mfg. Co.. 1160-1161 V. D. Anderson Co., The, 1410-1411 Rome-Turney Radiator Co., The, 1223 PYROMETERS, Portable and Stationary Illinois Testing Laboratories, 1311 MinneapoUs-HoneyweU Regulator Co., 1316-1317 Shaw-Perkins Mfg. Co., 1347 H. B. Smith Co., Inc., The, 1350 Trane Co., The, 1168-1169 Vulcan Radiator Co., The, 1224 Warren Webster A Co., 1437-1441 Young Radiator Co., 1173 ' RECORDERS, Humidity, Tem perature American Moistening Co., 1214 Electric Auto-Lite Co., The, Instru ment A Gauge Div., 1303 Moeller Instrument Co., 1318 Powers Regulator Co., The, 1321 Taylor Instrument Cos., 1326 RADIANT HEATING Burnham Corp., 1335 Campbell Heating Co., 1124-1125, 1142 Crane Co.. 1336-1337 Kritzer Radiant Coils, Inc., 1222 National Radiator.Co., The, 1340 1341 Sarcotherm Controls, Inc., 1433 United States Radiator Corp., 1344 1345 RADIATION, Aluminum Infra Insulation, Inc., 1482 Trane Co., The, 1168-1169 Young Radiator Co., 1173 - RADIATION, Baseboard, Fer rous .. American Radiator A Standard ' Sanitary Carp., 1328-1331 Burnham Corp., 1335 ' Crane Co., 1336-1337 C. A. Dunham Co., 1415-1419 Fedders-Quigan Corp., 1153 ' Kritzer Radiant Coils, Inc., 1222 National Radiator Co., The, 1340 1341 H. B. Smith Co., Inc., The, 1350 Trane Co., The, 1168-1169 Vulcan Radiator Co., The, 1224 Weil-McLain Co., 1351 - RADIATION. Baseboard, Nonferrous American Radiator A Standard Sanitary Corp., 1326-1331 C. A. Dunham Co., 1415-1419 Fedders-Quigan Corp- 1153 General Automatic Products Corp., 1338 Kritzer Radiant Cods, Inc., 1222 National Radiator Co., The, 1340 1341 Rome-Turney Radiator Co., The, 1223 RADIATOR BRACKETS (See Brackets, Radiator) RADIATOR ENCLOSURES AND SHIELDS American Flange A Mfg. Co., Ine., 1480 - National Radiator Co., The, 1340 1341 H. J. Somers, Inc., 1200-1201 RADIATOR , HANGERS (See Hangers, Radiator) . RADIATOR HEAT REFLEC TORS Infra Insulation, Inc., 1482 . Silvercote Products, Ino., 1484 REFRACTORIES, Cement, Ma terials . Armstrong Cork Co. (Building Ma- teriflJsDivJ, 1464 Babcock A Wilcox Co., The, 1352 Philip Carey Mfg. Co., The, 1448 1449 Johns-Manvflle, 1470-1471' ' Grant Wilson, Inc., 1452 REFRIGERATING EQUIP- MENT, Centrifugal Bell A Gossett Co., 1396-1397 Carrier Corp., 1106-1107 Trane Co., The, 1168-1169 Worthington Pump A Machinery Corp., 1118 York Corp., 1119 RADIATORS, Cabinet Airtherm Mfg. Co., 1141 American Radiator A Standard Sanitary Corp., 1328-1331 Crane Co., 1336-1337 REFRIGERATING EQUIP MENT, Steam Jet. Ingersoll-Rand, 1404 Worthington Pump A Machinery Carp., 1118 C. A. Dunham Co., 1415-1419 Fedders-Quigan Corp., 1153 Kritser Radiant Coils, Inc., 1222 Modine Mfg. Co., 1160-1161 National Radiator Co., The, 1340 1341 Shaw-Perkins Mfg. Co., 1347 United States Radiator Corp., 1344 1345 Young Radiator Co., 1173 REFRIGERATING MACHIN. ERY Airtemp Div., Chrysler Corp., 1126 1127 Baker Refrigeration Corp., 1225 Carrier Corp., 1106-1107 Curtis Refrigerating Machine Div., of Curtis Mfg. Co., 1227 Frick Co., 1228 Frigidaire Div., General Motors RADIATORS, Concealed Corp., 1110 Airtherm Mfg. Co., 1141 General Electric Co., 1108-1109 American Radiator A Standard Niagara Blower Co., 1112 .. Sanitary Corp., 1328-1331 Ready-Power Co., The, 1231 Crane Co., 1336-1337 Refrigeration Engineering, Inc., 1233 C. A. Dunham Co., 1415-1419 Trane Co., The, 1168-1169 Fedders-Quigan Coin., 1153 ' Worthington Pump A Machinery Kritzer Radiant Coils, Inc., 1222 Corp.. 1118 Modine Mfg. Co.. 1160-1161 York Corp., 1119 Please mention THE GUIDE 1952 when writing to Advertisers Index to Modem Equipment 1091 REFRIGERATION CONTROLS Alco Valve*Co., Ine., 1299 General^Controls, 1306-1307 HubbeU Corp., The. 1310 Penn Controls, Inc., 1319 REGISTERS (See Grilles, Louvers) Air Control Products, Inc., 1264-1265 Auer Register Co., The, 1268 . Barber-Colman Co., 1269 Diamond Mfg. Co-, 1273 Dole Valve Co., The, 1443 Hart A Cooley Mfg. Co., 1274-1275 Hendrick Mfg. Co., 1276-1277 Independent Register Co., The, 1278 Pyle-National Co., The, (Multi Vent Div.), 1280-1281 Register A Grille Mfg. Co., Inc., 1279 Standard Stamping A Perforating Co., 1282 Stewart Mfg. Co. Inc., 1283 Titus Mfg. Corp., 1284-1285 Tuttle A Bailey, Inc., 1286-1287 United States Register Co., 1288 1269 Young Regulator Co., 1291 REGULATORS, Air Volume Barber-Colman Co., 1269 Johnson Service Co., 1312-1313 Minneapolis-Honeywell Regulator Co., 1316-1317 Powers Regulator Co., The, 1321 Young Regulator Co., 1291 REGULATORS, Automatic Draft Walker Mfg. A Sales Corp., The, 1327 REGULATORS, Damper field Control Div., of H. D. Conkey A Co.. 1308 Fulton Sylphon Div., The, Robert- ahaw-Fulton Controls Co., 1304 1305 Hart A Cooley Mfg. Co., 1274-1275 Johnson Service Co., 1312-1313 Minneapolis-Honeywell Regulator Co., 1316-1317 Powers Regulator Co., The, 1321 Spence Engineering Co., Inc., 1324 Trane Co.. The, 1168-1169 Warren Webster A Co., 1437-1441 Young Regulator Co., 1291 1 REGULATORS, Humidity (See Humidity Control) REGULATORS, Pressure BeU A Gossett Co., 1396-1397 Detroit Regulator Co., 1302 C. A. Dunham Co.. 1415-1419 Fulton Sylphon Div., The Robert- shaw-Fulton Controls Co., 1304 1305 General Controls, 1312-1313 Hoffman Specialty Co., 1420-1423 HubbeU Corp., The. 1310 Illinois Engineering Co., 1424-1425 Johnson Service Co., 1312-1313 Jas. P. Marah Corp., 1428-1429 McDonnell A Miller, Inc., 1372-1375 Mercoid Corp., The, 1314 Monarch Mfg. Works, Inc., 1215 Penn Controls, Inc., 1319 Perfex Corp., 1320 Powers Regulator Co., The, 1321 Spence Engineering Co., Inc., 1324 Strong, Carlisle A Hammond Co., 1436 Swartwout Co., The, 1261 Taylor Instrument Cos., 1326 H. A. Thrush A Co.. 1398-1399 Webster Engineering Co., The, 1379 REGULATORS,. Remote Con trol HubbeU Corp., 1310 Mercoid Corp;, The, 1314 Minneapolis-HoneyweU Regulator Co., 1316-1317 Perfex Corp., 1320 Young Regulator Co., 1291 REGULATORS. Temperature (See Temperature Control) REGULATORS, Time Controls General Controls, 1306-1307 Minneapolis-HoneyweU Regulator Co., 1316-1317 Perfex Corp., 1320 RELIEF VALVES (See Valves, Rdief) ROOF COOLER April Showers Co., Inc., 1459 SEPARATORS, Dust . American Air Filter Co., 1183-1185 V. D. Andereon Co., The, 1410-1411 DoUinger Corp., 1194-1195 SEPARATORS, Gas V. D. Anderson Co.. The, 1410-1411 SEPARATORS, Oil Acme Industries, Inc., 1216 Air-Maze Corp., 1180-1182 DoUinger Corp.. 1194-1105 Illinois Engineering Co., 1424-1425 Warren Webster A Co., 1437-1441 York Corp., 1119 SEPARATORS, Refrigerant Oil Acme Industries, Inc., 1216 SEPARATORS, Steam V. D. Anderson Co., The, 1410-1411 IUinois Engineering Co., 1424-1425 W. H. Nicholson A Co., 1430-1431 Strang, Carlisle A Hammond Co., 1436 Warren Webster A Co., 1437-1441 SEPARATORS, Vapor V. D. Anderson Co,, The. 1410-1411 SHADE SCREENING IngersoU Products, Div. Borg- Wamer Corp., 1481 SHEETS, Asbestos, Flat, and Corrugated Johns-Manville, 1470-1471 SHEETS, Copper Alloy American Brass Co., The, 1174-1175 Revere Copper A Brass, Ine^ 1177 SHEETS. Copper Bearing Steel United States Steel, 1292 SHEETS, Galvanized United States Steel, 1292 . SHEETS, Higb Tensile United States Steel, 1292 - SHEETS, Special Finish United States Steel, 1292 REGULATORS, Draft Field Control DivM of H. D. Conkey A Co., 1308 8implex Mfg. Co., 1323 Walker Mfg. A Sales Corp., The, 1327 REGULATORS, Evaporator Pressure Alco Valve Co., 1299 HubbeU Corp., The, 1310 REGULATORS, Feed Water McDonnell A Miller, Inc., 1372-1375 Penn Controls, Inc., 1319 REGULATORS, Furnace Field Control Div., of H. D. Conkey A Co., 1308 Mercoid Corp., The, 1314 Minneapolis-HoneyweU Regulator Co., 1316-1317 RUST INHIBITOR Vinco Co., Inc., The, 1370-1371 RUST AND SCALE REMOVER Vinco Co., Inc., The, 1370-1371 RUST PREVENTATIVE (See Cor rosion, Treatment of) SAFETY CONTROLS (See Burner Protection, Gas and OH) SAFETY VALVES (See Valves, Safety) . SCREENING SHADE (See Shade Screening) SCREENS. Perforated Metal Diamond Mfg. Co., 1273 SHEETS, Stainless Steel American Flange A Mfg. Co^ Ine^ 1480 United States Steel, 1292 SHEETS, Steel American Flange A Mfg. Co., Inc.f 1480 United States Steel, 1292 SHUTTERS, Automatic American Foundry A Furnace Co., 1120-1121 Dole Valve Co., The, 1443 General Blower Co., 1241 Hg Electric Ventilating Co., 1156, 1244 Herman Nelson Div., American Air Filter Co.. Inc., 1164-1165 L. J. Wing Mfg. Co., 1170-1172 SKYLIGHTS, Insulated American 3 Way-Luxfer Prism Co., 1461 REGULATORS, Gas Detroit Regulator Co., 1303 General Controls, 1306-1307 Minneapolis-HoneyweU Regulator Co.. 1316-1317 Penn Controls, Inc., 1319 Webster Engineering Co., The, 1379 SEPARATORS, Air American Solvent Recovery Corp., 1186-1187 V. D. Anderson Co., The. 1410-1411 DoUinger Corp., 1194-1195 W. H/Nicholson A Co.. 1430-1431 Strong, Carlisle A Hammond Co., 1436 SMOKE DETECTORS AND INDICATORS (For Flues and Ducts) Combustion Control Corp., 1301 SOOT DESTROYER Vinco Co., Inc., The, 1370-1371 Numerals following Mant facturers* Names refer to pages lx i the Catalog Date Section 1092 1952 Guide SOUND DEADENING, Insulatlon Celotex Corp., The. 1466 Insul-Mastic Corp. of America, 1467 Insulite, 1466-1469 Johns-Manville, 1470-1471 Mundet Cork Corp., 1465 Owens-Coming Fiberglas Corp., Combustion Engineering - Super heater, Inc., 1354-1355 Crane Co., 1336-1337 Meyer Furnace Co., The, 1130-1131 STRAINERS, Air Maid-O'-Miet, Inc., 1426-1427 SWITCHES, Stack Safety Mercoid Corp., The, 1314 Minneapolis-Honeywell Regulator Co., 1316-1317 Penn Controls, Inc., 1319 TANK COILS (See Coils, Tank) 1451 Pacific Lumber Co., The, 1478 Union Asbestos & Rubber Co.. 1456-1457 Grapt Wilson, Inc., 1452 Wood Conversion Co., 1479 STRAINERS. Dirt . V. D. Anderson Co., The, 1410-1411 Armstrong Machine Works, 1412 1413 C. A. Dunham Co., 1415-1419 TANK COVERING (See Covering Pipe) TANK HEATERS (See Heaters, Tank) Hoffman Specialty Co., 1420-1423 ' SOUND DEADENING (See Vibra Illinois Engineering Co., 1424-1425 TANKS. Blow-off tion Absorber*) Sarco Co.. Inc., 1434-1435 Sterling, Inc., 1325 Farrar A Trefts, Inc., 1359 International Boiler Works Co., SPRAY DRYER {See Spray Equip Warren Webster A Co., 1437-1441 The, 1362 ment) SPRAY EQUIPMENT Binks Mfg. Co., 1206-1207 Monarch Mfg. Works, Inc., 1215 D. J. Murray Mfg. Co., 1168 Yarnall-Waring Co., 1442 SPRAY NOZZLE COOLING SYSTEM American Moistening Co., 1214* April Showers Co., Inc., 1459 Bmks Mfg. Co., 1206-1207 Lilie-Hoffman Cooling Towers, Inc., 1210 Marley Co., Inc., The, 1211 Monarch Mfg. Works, Inc., 1215 D. J. Murray Mfg. Co., 1163 Yarnall-Waring Co., 1442 SPRAY NOZZLES American Moistening Co., 1214 April Showere Co., Inc., 1459 Bahnson Co., The, 1102-1103 Binks Mfg. Co., 1206-1207 . STRAINERS, Gas Maid-O'-Mist, Inc., 1426-1427 STRAINERS, Oil Ace Engineering Co., 1382 V. D. Anderson Co., The, 1410-1411 Armstrong Machine Works, 1412 1413 Bell A Goesett Co., 1396-1397 Hubbell Corp., The, 1310 Monarch Mfg. Works, Ine., 1215 Sarco Co., Inc., 1434-1435 Spence Engineering Co., Inc., 1324 Sterling, Inc., 1325 STRAINERS, Refrigerant Alco Valve Co., 1299 General Controls, 1306-1307 Henry Valve Co., 1309 Hubbell Corp., The, 1310 Maid-O'-Mist, Ine., 1426-1427 Penn Controls, Idc., 1319 Sarco Co., Inc., 1434-1435 Sterling, Inc., 1325 TANKS, Pressure Farrar A Trefts, Inc., 1359 . International Boiler Works Co., The, 1362 Trane Co., The, 1168-1169 TANKS, Storage Farrar A Trefts, Inc., 1359 International Boiler Works Co., The. 1362 * Rheem Mfg. Co., 1136 Western Blower Co., 1255 TEMPERATURE CONTROL American Flange A Mfg. Co., Inc.. 1480 Barber-Colman Co., 1269 Cam-Stat, Inc., Div. of the Paul Henry Co., 1300 ' Crane Co., 1336-1337 Fluid Systems, Inc., 1376-1377 Fulton Sylphon Div., The, Robert shaW'Fulton Controls Co., 1304 1305 General Controls, 1306-1307 Buensod-Stacey, Inc., 1104 Hoffman Specialty Co., 1420-1423 Buffalo Forge Co., 1238 STRAINERS, Steam Illinois Engineering Co., 1424-1425 Marley Co., Inc., The, 1211 Monarch Mfg. Works, Inc., 1215 D. J. Murray Mfg. Co., 1163 Parks-Cramer Co., 1114-1115 ' Alco Valve Co., 1299 Illinois Testing Laboratories. Inc.. V. D. Anderson Co., The, 1410-1411 1311 Armstrong Machine Works, 1412- Johnson Service Co., 1312-1313 MIS Jas. P. Marsh Corp., 1423-1429 Water Cooling Equipment Co., 1213 Crane Co., 1336-1337 Mercoid Corp., The, 1314 Yarnall-Waring Co., 1442 C. A. Dunham Co., 1415-1419 Grinneli Co., Inc., 1154-1155 Minneapolis-Honeywell Regulator Co., 1316-1317 STEAM GENERATORS, Unit Cleaver-Brooks Co., 1353 Combustion Engineering - Super heater, Inc., 1354-1355 Cyclotherm Corp., 1356 Dutton Boilers, Div. Hapman- Dutton Co., 1358 Footer Wheeler Corp., 1209 Johnston Brothers, Inc.,-1363 Vapor Heating Corp., 1369 Worthington Pump A Machinery Corp., 1118 York-Shipley, Inc., 1394 Illinois Engineering Co., 1424-1425 Maid-O'-Mist, Inc., 1426-1427 Sarco Co., Inc., 1434-1435 Spence Engineering Co., Inc., 1324 Sterling, Inc., 1325 Strong, Carlike A Hammond Co., 1436 Trane Co., The, 1168-1169 STRAINERS, Water Alco Valve Co., 1299 V. D. Anderson Co., The, 1410-1411 Armstrong Machine Works, 1412 1413 Penn Controls, Inc., 1319 . ` Perfex Corp., 1320 Powers Regulator Co., The, 1321 Baroo Co., Inc., 1434-1435 Sarcotherm Controls, Inc., 1433 Spence Engineering Co., Inc., 1324 Staling, Inc., 1325 Taylor Instrument Coe., 1326 Warren Webster A Co., 1437-1441 Yarnall-Waring Co., 1442 Young Regulator Co., 1291 TEMPERING VALVES Valves, Tempering) (See STEAM HEATING SYSTEMS (See Heating Systems, Steam) Hubbell Corp., The, 1310 Illinois Engineering Co., 1424-1425 Maid-O'-Mist, Inc., 1426-1427 Monarch Mfg. Works, Inc., 1215 TESTING LABORATORY United States Testing Co.,Ino., 1485 STEEL INSULATION (See In Sarco Co., Inc., 1434-1435 sulation, Steel) 8pence Engineering Co., Inc., 1324 THERMOMETERS, Distance Sterling, Inc., 1325 Type STOKER MOTORS (See Motors, Trane Co., The, 1168-1169 Electric) ' Yarnall-Waring Co., 1442 Electric Auto*Lite Co., The Instru ment A Gauge Div., 1303 Fulton Sylphon Div., The. Robert- STOKERS, Mechanical, Anthra cite Airtemp Div., Chrysler Corp., 1126-- 1127 Combustion Engineering - Super heater. Inc., 1354-1355 SWITCHES, Float Alco Valve Co., 1299 McDonnell A Miller, Inc., 1372-1375 SWITCHES, Flow Control McDonnell A Miller, Inc., 1372-1375 ehaw-Fulton Controls Co., 1304 1305 Illinois Testing Laboratories, Inc., 1311 Johnson Service Co.. 1312-1313 Jas. P. Marsh Corp., 1428-1429 Minneapolis-Honeywell Regulator STOKERS, Mechanical, Bitu minous Airtemp Div., Chrysler Corp., 1126 1127 SWITCHES, Mercury Mercoid Corp., The, 1314 Minneapolis-Honeywell Regulator Co., 1316-1317 Co., 1316-1317 Moeller Instrument Co., 1318 Powers Regulator Co., The, 1321 Sarco Co., Inc., 1434-1435 Taylor Instrument Cos., 1326 Please mentit n THE GUIDE 1952 when writing to Advertisers Index to Modem Equipment 1093 THERMOMETERS, Indicating Electric Auto-Lite Co., The, Instru ment A Gauge Div., 1303 Fulton Sylphon Div., The, Robert- shaw-Fulton Controls Co., 1304 1305 Illinois Testing Laboratories, Inc., 1311 Johnson Service Co., 1312-1313 Jas. P. Marsh Corp., 1428-1429 Minneapolis-Honeywell Regulator Co., 1316-1317 Moeller Instrument Co., 1318 Powers Regulator Co., The, 1321 Rochester Mfg. Co., 1322 Sarco Co., Inc., 1434-1435 Taylor Instrument Coe., 1326 Jaa. P. Marsh Corp., 1428-1429 Sarco Co.. Inc.. 1434-1435 . Strong, Carlisle A Hammond Co., 1436 Trane Co., The. 1168-1169 TRAPS. Float V. D. Anderson Co., The, 1410-1411 Armstrong Machine Works, 1412 1413 Barnes A Jones, Inc., 1409 Crane Co., 1336-1337 C. A. Dunham Co., 1415-1419 ' Illinois Engineering Co., 1424-1425 Jas. P. Marsh Corp.. 1428-1429 W. H. Nicholson A Co., 1430-1431 Saco Co., Inc., 1434-1435 Trane Co., The, 1168-1169 Crane Co., 1336-1337 C. A. Dunham Co., 1415-1419 Grinneli Co.. Inc., 1154-1155 Hoffman Specialty Co., 1420-1423 Illinois Engineering Co., 1424-1425 Jas. P. Marsh Corp., 1428-1429 W. H. Nicholson A Co., 1250 * Powers Regulator Co., The, 1321 Sarco Co., Inc., 1434-1435 Sterling, Inc., 1325 TraneCo., The, 1168-1169 Warren Webster A Co., 1437-1441 TRAPS, Vacuum ' V. D. Anderson Co., The, 1410-1411 Armstrong Mar>Vnnn Works, 1412 1413 Barnes A Jones, Inc., 1409 THERMOMETERS, Recording Electric Auto-Lite Co., The, Instru ment A Gauge Div., 1303 Johnson Service Co., 1312-1313 Minneapolis-Honeywell Regulator Co., 1316-1317 Moeller Instrument Co., 1318 Powers Regulator Co., The, 1321 Taylor Instrument Cos., 1326 TRAPS, Float and Thermostatic V. D. Anderson Co., The, 1410-1411 Barnes A Jones, Inc., 1409 C. A. Dunham Co., 1415-1419 Grinneli Co., Inc., 1154-1155 . Hoffman 8pkdalty Co., 1420-1423 Illinois Engineering Co., 1424-1425 Jas. P. Marsh Corp., 1428-1429 Illinois Engineering Co., 1424-1425 ' Jas. P. Marsh Corp., 1428-1429 Strong, Carlisle A Hammond Co., 1436 TUBES, Boiler Babcock A Wilcox Tube Co., -The, 1352 THERMOSTATS Barber-Colman Co., 1269 Cam-Stat, Ino.. Div. of the Paul Henry Co., 1300 Crane Co., 1336-1337 Fulton Sylphon Div., The, Robert- shaw-Fulton Controls Co., 1304- W. H. Nicholson A Co., 1430-1431 Sarco Co., Inc.. 1434-1435 Sterling, Inc., 1325 Strong, Carlisle A Hammond Co., 1436 Trane Co., The, 1168-1169 Warren Webster A Co., 1437-1441 TUBES, Copper American Brass Co., The, 1174-1175 Revere Copper A Brass, Inc., 1177 TUBES, Pitot (See Air Measuring and Recording instruments) 1305 General Controls, 1312-1313 Hoffman Specialty Co., 1420-1423 TRAPS, Radiator Barnes A Jones, Ine., 1409 Crane Co., 1336-1337 TUBING, Aluminum Revere Copper A Brass, Inc., 1177 Johnson Service Co., 1312-1313 C. A. Dunham Co., 1415-1419 Mercoid Corp,, The, 1314 Minneapolis-Honeywell Regulator Co., 1316-1317 Penn Controls, Inc.. 1319 Grinneli Co., Inc., 1154-1155 Hoffman Specialty Co., 1420-1423 Illinois Engineering Co., 1424-1425 Jas. P. Marsh Corp., 1428-1429 TUBING, Copper . American Brass Co., The, 1174-1175 Revere Copper A Brass, Inc., 1177 Perfex Corp., 1320 W. H. Nicholson A Co., 1430-1431 Powers Regulator Co., The, 1321 Sarco Co., Inc., 1434-1435 TUBING, Fabricated Sareo Co., Inc., 1434-1435 Sterling, Ino., 1325 Revere Copper A Brass, Inc., 1277 Sarcotherm Controls, Inc., 1433 TraneCo., The, 1168-1169 H. A. Thrush A Co., 1398-1399 Vapor Heating Corp., 1369 United States Radiator Corp., 1344 1345 Warren Webster A Co.. 1437-1441 TUBING, Finned Aerofin Corp., 1217-1219 Fedders-Qmgan Corp., 1153 TIME SWITCHES, (See Switches, GAO Mfg. Co., The, 1220 Electric and Time) TRAPS, Return Kritzer Radiant Coils, Inc., 1222 Crane Co., 1336-1337 Rome-Turney Radiator Co., The, TIMERS, Electric, Interval Barber-Colman Co., 1269 Photoswitch, Inc., (Affiliate of Com* bastion Control Corp.), 1301 TIMERS, Electric, Sequence Photoswitch, Inc., (Affiliate of Com C. A. Dunham Co., 1415-1419 Hoffman Specialty Co., 1420-1423 Illinois Engineering Co., 1424-1425 Jas. P. Marsh Corp., 1428-1429 Sarco Co., Inc., 1434-1435 Trane Co., The. 1168-1169 TRAPS, Scale 1223 Vulcan Radiator Co., The, 1224 TUBING. Flexible Metallic American Brass Co., The, 1174-1175 Chicago Metal Hose Div., Flexonics Corp., 1176 bustion Control Corp.), 1301 Tllinmn Engineering Co., 1424-1425 TUBING, Steel TOWERS, Cooling, (See Coding- TRAPS, Scale, Refrigerant Revere Copper A Brass, Inc., 1177 Towers) Henry Valve Co., 1309 TURBINES TRANSFORMERS Aldrich Co., 1332 General Controls, 1306-1307 Wagner Electric Corp., 1257 TRAPS, Steam V. D. Anderson Co.. The, 1410-1411 Armstrong Machine Works, 1412-- 1413 Barnes A Jones, Inc., 1409 Pyle-National Co., The, 1280-1281 L. J. Wing Mfg. Co,, 1170rll72 Worthington Pump A Machinery Corp., 1118 . TRAPS. Air V. D. Anderson Co., The, 1410-1411 Armstrong Machine Works, 1412 Crane Co., 1336-1337 C. A. Dunham Co., 1415-1419 Hoffman Specialty Co., 1420-1423 Illinois Engineering Co., 1424-1425' UNDERGROUND PIPE DUITS (See Conduits, ground Pipe) CON Under 1413 Jas- P. Marsh Corp., 1428-1429 W. H. Nicholson A Co., 1430-1431 W. H. Nicholson A Co.. 1430-1431 UNIT HEATERS (See Heaters, Barco Co., Inc., 1434-1435 Sarco Co.. Inc., 1434-1435 Unit) ' Strong, Carlisle A Hammond Co., Sterling, Inc., 1325 1436 TRAPS, Bucket V. D. Anderson Co., The, 1410-1411 Armstrong Machine Works, 1413-- 1413 Strong, Carlisle A Hammond Co., 1436 Trane Co., The, 1168-1169 Vapor Heating Corp., 1369 Warren Webster A Co., 1437-1441 Yarnall-Waring Co., 1442 UNIT VENTILATORS (See Ven tilators, Unit) UNITS, Air Conditioning (See Air Conditioning Units) Crane Co., 1336-1337 C. A. Dunham Co., 1415-1419 Hoffman Specialty Co., 1420-1423 TRAPS, Thermostatic Barnes A Jones, Inc., 1409 VACUUM HEATING SYSTEMS (See Heating Systems, Vacuum) Numerals following Manufacturers' Names refer to pages in the Catalog Data Section 1094 1952 Guide -VACUUM REFRIGERATING Powers Regulator Co., The, 1321 VALVES, Packless SYSTEMS Ingentoll-Rand, 1404 Taylor Instrument Coe., 1326 C. A. Dunham Co., 1415-1419 - Fulton Sylphon Div., The, Robert* VALVES. Air Crane Co.. 1330-1337 Dole Valve Co.. The, 1443 Hammond Brass Works, 1445 ' Hoffman Specialty Co., 1420-1423 Homestead Valve Mfg. Co., 1440 Jenkins Bros., 1447 Maid-O'-Mist, Inc., 1426-1427 VALVES, Exhaust Maid-O'-Mist, Inc.. 1426-1427 VALVES, Expansion Alco Valve Co., 1299 Crane Co., 1336-1337 General Controls, 1312-1313 Henry Valve Co., 1309 shaw-Fulton Controls Co., 1304 - " 1305 General Controls, 1306-1307 Henry Valve Co;, 1309 Hoffman Specialty Co., 1420-1423 Illinois Engineering Co., 1424-1425 Jas. P. Marsh Corp., 1428-1429 Minneapolis-Honeywell Regulator Co., 1316-1317 Jas. P. Marsh Corp., 1428-1429 Ohio Brass Co., 1432 W. H. Nicholson A Co., 1430-1431 VALVES, Float Ohio Brass Co., 1432 Alco Valve Co., 1299 Powers Regulator Co., The, 1321 Sarco Co., Inc., 1434-1435 Hubbell Corp., The, 1310 VALVES, Angle, Cross Crane Co.. 1336-1337 Globe and Illinois Engineering Co., 1424-1425 Maid-O'-Mist, Inc.. 1426-1427 McDonnell A Miller, Inc., 1372-1375 VALVES, Pressure Reducing (S Regulators, Pressure) . Fairbanks Co., The, 1444 Frick Co., 1228 Grinnell Co., Inc., 1154-1155 Hammond Brass Works, 1445 Henry Valve Co., 1309 Jenkins Bros., 1447 Ohio Brass Co., 1432 VALVES, Flow Control Bell A Gossett Co., 1396-1397 VALVES, Radiant Heating Homestead Valve Mfg. Co., 1446 Crane Co., 1336-1337 General Controls, 1312-1313 VALVES, Radiator Homestead Valve Mfg. Co., 1448 American Radiator A Standard Illinois Engineering Co., 1424-1425' Sanitary Corp., 1328-1331 Jas. P. Marsh Corp., 1428-1429 Barnes A Jones, Inc., 1409 VALVES, Automatic McDonnell A Miller, Inc., 1372-1375 Crane Co., 1336-1337 Fulton Sylphon Div., The, Robert- Ohio Brass Co., 1432 C. A. Dunham Co., 1415-1419 . shaw-Fulton Controls Co., 1304 Taco Heaters, Inc., 1400 Fairbanks Co., The, 1444 . 1305 H. A. Thrush A Co., 1398-1399 Fulton Sylphon Div., The, Robert- General Controls, 1306-1307 Hubbell Coro., The. 1310 Jas. P. Marsh Corp., 1428-1429 McDonnell & Miller, Inc., 1372-1375 Minneapolis-Honeywell Regulator Co., 1316-1317 Sarcotherm Controls, Inc., 1433 Sterling, Inc., 1325 VALVES, Gas Hammond Brass Works, 1445 Homestead Valve Mfg. Co., 1446 Jenkins Bros., 1447 Ohio Brass Co., 1432 Penn Controls, Inc., 1319 ' Perfex Corp., 1320 ahaw-Fulton Controls Co., 1304 1305 Grinnell Co.. Inc., 1154-1155 Hammond Brass Works, 1445 Hoffman Specialty Co., 1420-1423 Illinois Engineering Co.,. 1424-1425 Jenkins Bros., 1447 - Maid-O'-Mist, Inc., 1426-1427 Jas. P. Marsh Corp., 1428-1429. VALVES, Back Pressure Alco Valve Co., 1299 General Controls, 1306-1307 Hubbell Carp., The, 1310 Illinois Engineering Co., 1424-1425 VALVES, Gate Crane Co., 1336-1337 Fairbanks Co., The, 1444 General Controls, 1306-1307 Hammond Brass Works, 1445 Jenkins Bros, 1447 Ohio Brass Co., 1432 Minneapolis-Honeywell Regulator Co., 1316-1317 Ohio Brass Co., 1432 Sarco Co., Inc., 1336-1337 Sterling, Inc., 1325 ` Taco Heaters, Inc., 1400 Trane Co., The, 1168-1169 VALVES, Balanced General Controls, 1306-1307 Illinois Engineering Co., 1424-1425 Maid-O'-Mist, Hie., 1426-1427 VALVES, Humidifier Maid-O'-Mist, Inc., 1426-1427 VALVES, Radiator, Humidify ing Maid-O'-Mist, Inc., 1426-1127 McDonnell & Miller, Inc., 1372-1375 Minneapolis-Honeywell Regulator Co., 1316-1317 . VALVES, Hydraulic Homestead Valve Mfg. Co., 1446 Jenkins Bros., 1447 VALVES, Radiator Orifice. Barnes A Jones, Inc., 1409 W. H. Nicholson A Co., 1430-1431 C. A. Dunham Co., 1415-1419 VALVES, Blowoff Yarnall-Waring Co., 1442 Grinnell Co., Inc., 1154-1155 Fairbanks Co., The, 1444 Hammond Brass Works, 1445 Homestead Valve Mfg. Co., 1446 -Jenkins Bros., 1447 McDonnell A Miller, Inc., 1372-1375 Yarns11-Waring Co., 1442 . VALVES, By-Pass VALVES, Magnetic Alco Valve Co., 1299 General Controls, 1306-1307 Hook A Ackerman, Inc., 1339 Hubbell Coro.. The, 1310 McDonnell A Miller, Inc., 1372-1375 Illinois Engineering Co., 1424-1425 Minneapolis-Honeywell Regulator . Co*. 1316-1317 Ohio Brass Co., 1432 Sarco Co,, Inc., 1434-1435 Warren Webster A Co., 1437-1441 General Controls, 1306-1307 Jenkins Bros., 1447 VALVES, Check Fairbanks Co., The, 1444 Grinnell Co., Inc., 1154-1155 Hammond Brass Works, 1445 VALVES, Mixing, Thermostatic Fulton Sylphon Div., The, Robert* shaw-Fulton Controls Co., 1304 1305 Powers Regulator Co., The, 1321 Sarco Co., Inc., 1434-1435 VALVES, Radiator, Pneumatic Diaphragm Johnson Service Co., 1312-1313 Minneapolis-Honeywell Regulator Co., 1316-1317 Powers Regulator Co., The, 1321 Henry Valve Co., 1309 Hubbell Corp., The, 1310 VALVES, Motor Operated - VALVES, Reducing Jenkins Bros., 1447 Barber-Colman Co., 1269 Bell A Gossett Co., 1396-1397 Ohio Brass Co., 1432 Bell A Gossett Co.. 1396-1397 Crane Co., 1336-1337 General Controls, 1306-1307 C. A. Dunham Co., 1415-1419 VALVES, Corrosion Resisting Crane Co., 1336-1337 Homestead Valve Mfg. Co., 1446 Jenkins Bros., 1447 Illinois Engineering Co., 1424-1425 Johnson Service Co., 1312-1313 W. H. Nicholson A Co., 1430-1431 Sarco Co., Inc., 1434-1435 Taylor Instrument Coe., 1326 Fulton Sylphon Div., The, Robert* shaw-Fulton Controls Co., 1304- 1305 . Illinois Engineering Co., 1424-1425 Strong, Carlisle A Hammond Co., Warren Webster A Co., 1437-1441 1438 VALVES, Diaphragm Crane Co., 1336-1337 General Controls, 1306-1307 VALVES, Non-Return Fairbanks Co., The, 1444 Taco Heaters, Ine., 1400 Taylor Instrument Cos., 1326 H. A. Thrush A Co., 1398-1399 Grinnell Co., Inc., 1154-1155 Hammond Brass Works, 1445 Henry Valve Co., 1309 Illinois Engineering Co., 1424-1425 VALVES, Refrigerant Line Hubbell Corp., The, 1310 Jenkins Bros., 1447 ' Alco Valve Co., 1299 Johnson Service Co., 1312-1313 Ohio Brass Co., 1432 Baker Refrigeration Corp., 1225 Please m< i THE GUIDE 1952 when writing to Advertisers ' Index to Modem Equipment 1095 Hammond Brass Works, 1445 Henry Valve Co., 1309 Jenkins Bros., 1447 Worthington Pump A Machinery - Corp., 1118 York Corp., 1119 ^. VAPOR BARRIERS Infra Insulation, Inon 1482 Reflectal Corp.. 1483 Silvercote Products, Inc., 1484 . . VAPOR HEATING SYSTEMS B&hnson Co., The, 1102-1103 Carrier Corp., 1106-1107 DeBothesat Fans Div., American Miwhinft A Mptftla, Inn , 1240 General Blower Co., 1241 ' Hg Electric Ventilating Co., 1166 1244 {See Healing Systems, Vapor) Jenn-Air Products Co., 1245 - VALVES, Relief Kennard Corp., 1157 Bell A Gossett Co., 1396-1397 Henry Valve Co., 1309 Maid-O'-Mist, Inc., 1426-1427 VENT FLUE Vent Flue) GAPS (See Caps, Herman Nelson Div., American Air Filter Co., Inc., 1164-1165 John J. Nesbitt, Inc., 1166 Jas. P. Marsh Corp., 1428-1429 New York Blower Co., The, 1250 McDonnell A Miller, Inc., 1372-1375 VENTILATORS, Attic (See Fans, Trane Co., The, 1168-1169 Mfg. WorkB, Inc., 1215 Electric, Propeller, Supply and L. J. Wing Mfg. Co., 1170-1172 Taco Heaters, Inc., 1400 Exhaust) H. A. Thrush A Co., 1390-1399 American Blower Corp., 1100-1101 Trane Co.. The, 1168-1169 American Coolair Corp., 1235 VENTILATORS, Window York Corp., 1119 G. C. Breidert Co., 1258 Air Control Products, Inc., 1264-1265 Philip Carey Mfg. Co., The. 1448 American Coolair Corp., 1235 VALVES, Safety General Controls, 1306-1307 Henry Valve Co., 1309 Jas. P. Marsh Corp., 1428-1429 McDonnell A Miller, Inc., 1372-1375 Milwaukee Gas Specialty Co., 1315 1449 Champion Blower A Forge Co., 1239 Clarage Fan Co., 1105 . DeBothesat Fans Div., American Machine A Metals, Inc., 1240 General Blower Co., 1241 Dg Electric Ventilating Co., 1156, Hg Electric Ventilating Co., 1166, 1244 Lau Blower Co., The, 1248 L. J. Wing Mfg. Co., 1170-1172 VIBRATION ABSORBERS (See VALVES. Solenoid Alco Valve Co., 1299 General Controls, 1306-1307 Jas. P. Marsh Coro., 1428-1429 McDonnell A Miller, In&, 1372-1375 W. H. Nicholson A Co., 1430-1431 1244 Lau Blower Co.. The, 1248 Torrington Mfg. Co., The, 1252-1253 Trade-Wind ifotorfans, Inc., 1254 Western Engineering A Mfg. Co., Inc.. 1262 L. J. Wing Mfg. Co., U70rll73 Sound Deadening) American Brass Co., The, 1174-1176 Celotex Corp-. The, 1466 Chicago Metal Hose Div., Flexonics Coro., 1176 . Mundet Cork Corp., 1465 Grant Wilson, Inc., 1462 Penn Controls, Inc., 1319 Spence Engineering Co., Inc., 1324 VENTILATORS, Floor and Wall WALLBOARD, Insulating Air Control Products, Inc., 1264-1265 Armstrong Cork Co., 1464 VALVES, Stop and Check (See .Valves, Non-Return) American Coolair Corp.. 1235 . Charles Demuth A Sons, Inc., 1272 DiamondlMfg. Co., 1273 Philip Carey Mfg. Co., The. 1448 1449 Celotex Corp., The, 1460 General Blower Co., 1241 Insulite, 1468-1469 VALVES, Tempering Dole Valve Co., The, 1443 Fulton Sylphon Div., The, Robert- shaw-Fulton Controls Co., 1304 1305 Powers Regulator Co., The, 1321 8aroo Co., Inc., 1434-1435 Taco Heaters, Inc., 1400 Hart A Cooley Mfg. Co., 1274-1275 Hendrick Mfg. Co., 1276-1277 . Hg Electric Ventilating Co., 1166, 1244 Independent Register Co., The, 1278 Jenn-Air Products Co., 1245 Register A Grille Mfg. Co., Inc., 1279 Titus Mfg. Corp., 1284-1285 Trane Co.. The, 1168-1169 Johns-Manvnie. 1470-1471 Mundet Cork Corp., 1465 Wood Conversion Co., 1479 WARM AIR FURNACES Furnaces, Warm Air) (See United States Register Co., 1288 WARM AIR HEATING SYSTEM VALVES, Thermostatic Alco Valve Co.. 1299 1289 Universal Diffuser Corp., 1290 (See Heating Systems, Furnace) Crane Co., 1336-1337 Fulton Sylphon Div., The, Robert- VENTILATORS, Roof WASHERS, Air (See Air Washers) shaw-Fulton Controls Co., 1304 Air Control Products, Inc., 1264-1265 1305 General Controls, 1308-1307 Illinois Engineering Co., 1424-1425 Jas. P. Marsh Corp., 1428-1429 Powers Regulator Co., The, 1321 Sarco Co., Inc.. 1434-1435 Spence Engineering Co., Inc., 1324 Sterling, Inc., 1325 Yarnall-Waring Co., 1442 VALVES, Water Flow Regulat ing Bell A Gossett Co., 1396-1397 Dole Valve Co., The, 1443 H. A. Thrush A Co., 1398-1399 VALVES, Water Level, Float Control Maid-O'-Mist, Inc., 1426-1427 VALVES. Water Regulating Alco Valve Co., 1299 Fulton Sylphon Div., The, Robert- shaw-Fulton Controls Co., 1304 1305 Hammond Brass Works, 1445 Jenkins Bros., 1447 Jas. P. Marsh Coro., 1428-1429 Air Devices, Inc., 1178, 1263 American Coolair Coro., 1235 . American 3 Way-Luxler Prism Co., 1461 G. C. Breidert Co., 1258 . DeBothexat Fans Div., American Machine A Metals, Inc., 1240 General Blower Co.. 1241 . Hartxell Propeller Fan Co., Div. of Castle Hills Corp., 1242 Hirschman-Pohle Co., Inc., 1259 Hg Electoic Ventilating Co., 1156, 1244 Iron Lung Ventilator Co., 1260 Jenn-Air Products Co., 1245 New York Blower Co., 1250 Propellair Div., Robbins A Myers Inc., 1251 SwartwoutJCo., The, 1261 Trade-Wind Motorfans, Inc., 1254 Trane Co., The, 1168-1169 Weston Engineering A Mfg. Co., Inc., 1262 ' L. J. Wing Mfg. Co., 1170-1172 VENTILATORS, Ship Air Devices, Inc., 1178, 1263 G. C. Breidert Co., 1258 L. J. Wing Mfg. Co.. 1170-1172 WATER COOLING (See Coolinq Equipment, Water; Cooling Towers) Acme Industries, Inc., 1216 Aerofin Corp., 1217-1219 - Baker Refrigeration Corp., 1225 Baltimore AirooQ Co., Inc., 1226 Binks Mfg. Co.. 1206-1207 Carrier Corp., 1106-1107 4 Curtis Refrigerating Machine Div. of Curtis Mfg. Co., 1227 Fedders-Quigan Corp., 1153 Fluor Corp., Ltd., The, 1208 Kennard Corp-, 1157 4 ____ Lilie-Hoffmann Cooling Towers, Inc., 1210 Marley Co., Inc., The, 1211 Mario Coil Co.. 1229 Modine Mfg. Co., 1160-1161 National Radiator Co., The, 1340 1341 Niagara Blower Co., 1112 Patterson-Kelley Co., Ine., The, 1221 . Refrigeration Economics Co., Inc., 1167 Trane Co., The, 1168-1169 __ Water Cooling Equipment Co., 1213 Westinghouse Electric Corp., Air Conditioning Div., 1117 , Worthington Pump de Machinery McDonnell A Millar, Inc., 1372-1375 Penn Controls, Inc., 1319 VENTILATORS, Unit Powers RegulatorlCo., The, 1321 American Blower Corp** 1100-1101 Sarco Co., Inc., 1434-1435 American Coolair Corp., 1235 Corp-. H18 Yarnall-Waring Co., 1442 York Corp-. 1H9 Young Radiator Co.* 1173 Numerals following Manufacturers* Names refer to pages in the Catalog Data Section 'gsW7 1096 1952 Guide. WATER COOLING, Spray Sys tems ' Air A Refrigeration Corp., 1099 American Blower Corp., 1100-1101 April SboweiB Co., Ino., 1459 Carrier Corp., 110fr-1107 Niagara Blower Co., 1113 Pittsburgh Lectrodryer Corp., 1113 Refrigeration Engineering, Inc., 1233 Trane Co., The, 1168-1169 Westinghouae Electrio Corp., Air Conditioning Div., 1117 fork Carp., 1119 * WATER COOLING TOWERS (See Cooling Towers, Water) WATER FEEDERS (See Feeders, Boiler Water) WATER HEATERS (See Heaters, WELDING FITTINGS (See Fit Hot Water Service) . tings, Welding) . WATER MIXERS, Thermostatic (See Valves, Tempering) Bell A.Gossett Co., 1396-1397 Dole Valve Co., The, 1443 WELDING ROD ' American Brass Co., The, 1174-1175 Revere Copper A Brass, Ine., 1177 Fulton Sylphon Div., The, Robert* ehaw-Fulton Controls Co., 1304 1305 Powers Regulator Co., The, 1321 Sarco Co., Inc., 1434-1435 Taco Heaters, Inc., 1400 WHEELS, Blower Champion Blower A Forge Co., 1239 Lau BtoweriCo., The, 1248 Morrison Products, Inc., 1249 Tonington Mfg. Co., The, 1253-1253 United States Air Conditioning WATER TREATMENT . Corp., 1116 Vinco Co., Inc.. The, 1370-1371 Worthington Pump A Machinery WHEELS, Spray (See Spray Equip Corp., 1118 < ment) i MANUFACTURERS' CATALOG DATA (PAGES 1099-1496) Please mention THE GUIDE 1952 when writing to Advertisers On pages 1099-14% will be found the Catalog Data of 277 manufacturers whose products are described and illustrated. For the convenience of the user of THE GUIDE 1952 there are eight main divisions: Air Conditioning....................................................1099-1173 Air Conditioning and Heating Piping............1174-1177 Air System Equipment........................................ 1178-1292 Bends, Coils, Fittings.......................................... 1293-1298 Controls and Instruments.................................. 1299-1327 Heating Systems................................................... 1328-1447 Insulation..................... 1448-1485 Publications.............................................................1486-1496 On pages 1073-1096, 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 producers address, may be located quickly. % ; I 'JS i Air Conditioning sS Air & Refrigeration Corporation 475 Fifth Avenue, New York 17, N. Y. 271 Milton Avenue, S. E., Atlanta, GA. Representatives in all major cities Air Conditioning, Humidifying, Dehumidifying, 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 Btation apparatus. For most purposes the Capillary Washer requires 14 the volume of water at }4 the pressure used by conventional spray equipment. They are available with factory insulated casings and 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, heat-' ing coils, Capillary Cells with suitable sprays, spray pump and mixing dampers. Units are designed for floor mounting _or for Spray Type Air Washers for washing, humidifying and dehumidifying air are all basically the same. A & R Spray Washers include special features of design de veloped 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 stations 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 dehumidifiers 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 remiire only bolting together to make enclosures of any required shape tor plenum chambers and many other purposes. Panels are available m widths from 3 in. to 48 in., and in lengths to 12 ft. Their use insures tremendous economies in field labor. For de tails, see Panel Bulletin. Write for catalog and engineering data. Registered Trade Mark 1099 Factory /netgated Plenum Chamber Air Conditioning m 1 Unit Systems American Blower Corporation Detroit 32, Michigan CANADIAN SIROCCO COMPANY, LTD. 310 Ellis Street, Windsor, Ontario Branch Offices in Principal Cities - Division of American Radiator ^ <$taudaml ^anitarti corporation ' AIR CONDITIONING -- HUMIDIFYING -- DEHUMIDIFYING -- COOLING -- VENTILATING -- HEATING -- VAPOR-ABSORPTION -- DRYING -- AIR WASHING AND PURIFICATION -- EXHAUSTING EQUIPMENT AND MECHANICAL DRAFT APPARATUS -f- American Blower Corporation Air Conditioning s^jtems 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. Capillar; 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. American Blower Air Washer--above, cleans, purifies and freshens air, removes dust, odors and bacteria, cools if desired and provides an effective method of con trolling humidity. Bulletin 3923. 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 Bulletin 1521 Type B booster coils Type W water coils Type C cleanable water coils Type X direct expan sion coils Bulletin B-1318 Type H heavy duty coils " "ABC" Utility Sets--complete packaged units, directly connected or V-Belt short coupled drive for duct applications. Sizes for wide variety of ventilating problems. Quiet, compact. Bulletin 2814. Double Inlet "ABC" Multiblade Fan-- above, is a heavy duty ventilating fan. The wheel has narrow, forward pitched blades. Low tip speeds assure quiet op-, eration. Request Bulletin A-801. Bul letin A-603 describes backwardlyinclined, nonoverloading HS Fan. 1100 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 6017. Gas . Fired Unit Heater--self con tained--available in 7 sizes for clean, automatic, instantaneous heating. Ad justable louvers assure efficient heat dis tribution throughout the work area. A. G. A. approved. Write for Bulletin 7117. Centrifugal Type Unit Heaters--for use with or without duct systems, for large hard to heat areas. Ideal for floor mounting. Request Bulletin 5917. American Blower Air Conditioning Units. --Type A for all normal unitary type commercial and industrial applications. Cooling, heating, humidifying. Capaci ties 1000 cfm--13600 cfm. Type S for commercial and industrial applications desiring washed air or high relative hu midities. Capacities 1000 cfm--13600 cfm. Type M, large capacity for central system installation with separately mounted fan. Cooling, dehumidifica tion, heating, humidifying. Capacities 1000 cfm--41000 cfm. Bulletin 6527. 1101 Air Conditioning Centra) System % Air Conditioning centrisjtem Winston-Salem, N. C HUMIDIFYING -- VENTILATING -- COOLING -- FILTERING COMPLETE SYSTEMS 1. HUMIDUCT--A unit system for indus trial air conditioning--designed, manu factured, and installed by Bahnson. Systems provide ventilating, heating, cooling, humidifying, dehumidifying and. filtering in any desired combination. 2. CENTRAL STATION--Systems for industrial and commercial applications --designed, manufactured and installed by Bahnson. Type Y or Centrispray Air Washers along with Bahnson manufac tured components provide complete temperature and humidity control. UNIT HUMIDIFIERS 3. TYPE E HUMIDIFIER--A self-con tained unit for smaller commercial and industrial rooms. Evaporates up to 7 gph with excellent distribution and low sound level. Installed singly or in groups with individual or group auto matic control. Requires only water supply and electrical connection. 4. 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. 5. TYPE BA-2 HUMIDIFIER--A high- capacity 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, drain, . and electrical connection. ' SYSTEM COMPONENTS 6. AIR WASHERS--Bahnson Type Y Ah' Washers cleanse, cool and provide humidity control. Available in sizes from 6000 cfm up, they can be provided with spray systems best suited for par ticular applications. Bahnson FLEXIDUR spray nozzles are used and auto matic suction strainers are available. Write for Further Information on the Equipment Shown Above. 1102 -s> Winston-Salem, N. C HEATING -- DEHUMIDIFYING -- AIR CLEANING -- VAPOR ABSORBTION 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. CENTRISPRAY EVAPORATOR--A combined fan and evaporator unit avail able in capacities up to 40,000 cfm. Pro vides high humidification and air hand ling capacity with the inherent economy of the Bahnson centrifugal atomization principle. .9. GRILLES -- Bahnson wide-blade grilles provide complete directional control of air flow. Special features include a removable core to facilitate cleaning as well as to provide access to the distribution duct. 10. MOTORIZED PSYCHROMETER-- A psychrometer for accurate and rapid reading of wet and dry bulb tempera tures--complete with humidity calcu- lator and record pad holder. 11. AUTOMATIC CONTROLS--Bahn son pneumatic or electric humidity and temperature controls are sensitive, accu rate and dependable. Available in as pirated cabinets combined with re corders. 12. TYPE ESC ATOMIZER--A Belfcleaning pneumatic atomizer of superior design for direct humidification or sup plementary evaporation. Uses both air and water under pressure to provide high evaporation at low power cost. Modulating control, regulates evapora tion in direct proportion to the room requirements. 13. FLEXIDUR SPRAY NOZZLE--A brass spray nozzle with orifice stamped from stainless steel to eliminate erosion, prevent accumulation of foreign matter, and assure uniformity of spray pattern. 14. TYPE DC SPRAY NOZZLE--The Bahnson Type DC Spray Nozzle utilizes the principle of impingement of water jets to produce a fine uniform spray. This can result in a saving in pumping cost of 50 per cent over conventional spray nozzle systems. Write for Further Information on the Equipment Shown Above. 1103 Air Conditioning BUENSDD-STACEY ^ UKORWIUTtD TM 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 Long Island City, N. Y., with complete Bheet _ ---*> metal and pipe shops in each. Buensod- Stacey also manufactures many compo nents 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. 4 .-J5K-* *W Buensod-Stacey Special Defiumidificr 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 BUENSOD - STACEY ROTARY STRAINERS save maintenance dollars. Constructed of stainless steel, they are especially useful where the air contains large, quantities of solids such as lint in textile mills. ' Buensod-Stacey Rotary Strainer BUENSOD-STACEY DUAL DUCT SYSTEM* for air conditioning multi-story and multi-room buildings is a practical and economical' way to obtain individually con trolled temperatures in each enclosed space of such structures as office buildings, laboratories, apartment houses and hotels. This system, which is a simple combina tion of high pressure, high velocity, cold and warm air ducts, distributes the air at desired temperature through Buensod-Stacey Vertical and Horizontal Air Dis tributing and Mixing Units. It does not require widely scattered coils, fans or other mechanical apparatus. 'Protected by patent applications. 1104 Air Conditioning g"nSs Clarage Fan Company Kalamazoo, Michigan Application Engineering Offices (Consult Telephone Directory) Clarage Air Handling and Conditioning Equipment FANS AND BLOWERS AIR WASHERS CONDITIONING UNITS UNIT HEATERS For over 35 years Clarage has been a leading manufacturer of equipment and units for ventilating, exhausting, cooling, air cleaning, humidifying and .complete conditioning. Clarage equip ment is designed to meet all types of industrial, commercial and public build ing requirements. Only a few examples of the complete Clarage line are shown on this page. Clarage Unit Heaters are available foi 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 Fans are offered in many dif ferent standard types and arrangements. Sizes range from 200 to 200,000 cfm. Equipment is designed for slow speed (quiet) and high speed operation, either V-belt or direct motor driven. Most 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 dehumidi- fying purposes. sizes quickly adjustable for any of 8 di We welcome your inquiry on any air rections of air discharge. Special fans handling or conditioning problem. Con constructed for special industrial appli tact our nearest branch office, or write us cations can be furnished. at Kalamazoo, Michigan. 1105 _' Air Conditioning Carrier Corporation Syracuse 1, N. Y. MARINE DIVISION: 385 Madison Are. 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. Room Air Conditioners--for individual rooms and offices in compact modem styl ingand handsome finish to blend with fin est of interior furnishings. Window sill models in H, 14, % ana 1 hp capacity. Console models in 1 and 114 hp capacity. Weathermakers--completely self-con tained air conditioners for commercial and industrial applications. Six sizes from 3 to 20 hp cooling capacity. Year-Round Weathermakers--for heat ing and cooling in residential and com mercial applications. Compact, efficient pas heating combined with summer cool ing. Four combination sizes. Zoning Weathermakers--blow-through fan-cml units for air conditioning sys tems using remote sources of heat and refrigeration. In six sizes for comfort and industrial applications. System Weathermakers--fan-coil uni tary air conditioners for application to central cooling and heating systems for comfort and industrial use. Five sizes in vertical and horizontal models. Central Station Air Conditioners--for application with fan and duct systems for large spaces such as Btores, 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 Weathermasters. 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. 1106 AIR CONDITIONING Carrier Corporation Air Conditioning sJSSL, Carrier REFRIGERATION 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 standardmotor or turbine drive. Available in capacities from 100 to 2500 tons. Absorption Refrigerating Machines--for producing chilled water at 36 F or higher in fully automatic operation from 10 to 100 per cent capacity. Uses high or low pressure steam for operation. Capac ities 115,150,200, 270 and 350 tons. Reciprocating Refrigerating Machines-- for comfort and industrial air condition ing and for process cooling. Direct or belt drive, water or evaporative cooled types from 5 to 100 horsepower. 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 75 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. Carrier) INDUSTRIAL HEATING Unit Heaters--for commercial and indus trial space heating using steam or hot water. Complete range of sizes in two types: Model 46U Horizontal Discharge in capacities from 21,000 to 200,000 Btu per hour, and Model 46S Four-way Directed-flo in capacities from 82,000 to 500,000 Btu per hour at 2 lb steam. Gas-Fired Unit Heaters--for clean, eco nomical heat in offices, stores, factories and similar spaces where gas is avail able. Approved for manufactured, mixed, natural and LP gases. Capac ities: 70,000 to 230,000 Btu per hour. Heat Diffusers--for ventilating as well as. heating large commercial and indus trial spaces. Floor, wall or ceiling mounted with coils for steam or hot water. Capacities 115,000 to 1,720,000 Btu per hour at 2 lb steam. 1107 Air Conditioning GENERAL ELECTRIC HOME HEATING and YEAR 'ROUND AIR CONDITIONING . Air Conditioning Division, Bloomfield, New Jersey REGIONAL OFFICES: * .. New York 22, N. Y.--570 Lexington Ave. ' Chicago 54,UL--Merchandise Mart, Room 1144 New Orleans 12, La.--511 International Trade Mart - San Francisco 6, Cal.--235 Montgomery St. See your classified telephone directory for local sources under: G-E Home Heating Equipment--G-E Air Conditioning G-E Refrigeration Machines--G-E Water Coolers For information on equipment for large commercial or industrial installations: Call or write Manager, Direct Sales, Air Conditioning Division, Bloomfield, N. J. 1. G-E ROOM AIR CONDITIONERS (WINDOW MOUNTED) For offices, homes, apartments, hotels, and wherever small space cooling is required. Easily installed and serviced. Re quires no plumbing--merely an electrical connection. Fits most standard windows. Performs same function as larger air conditioning units. Two handsome models--4 and J hp. 2. G-E PERSONAL WEATHER CONTROL AIR CONDI TIONING SYSTEMS For office buildings, hotels, hospitals, and other multi-room structures. Room air conditioner (remote type) controlled by each tenant. No ductwork required. Quiet--refrigeration machines installed elsewhere. Compact, attractive cabinets-- only 26 in. high, 9 in. deep--enclose fans, filters, coils, and con trols. Three sizes: f to 14 tons cooling, corresponding heating capacities. 3. G-E CENTRAL PLANT AIR CONDITIONERS For large space and multi-room building cooling and heating. G-E sectional design permits 12 vertical and 8 horizontal ar rangements. Saves engineering and installation time, saves valuable space. Cooling, heating, year 'round air condi tioning. Five sizes: 1,000 to 12,800 cfm. 4. G-E PACKAGED AIR CONDITIONERS For industrial areas, office suites, stores, etc. Units cool, dehumidify, filter, ventilate, and circulate, (heat, if desired). Fast installation, economical operation. Muggy Weather Control on 3, 5, and 74 hp sizes reduces clamminess without chilling. Five self-contained models: 2 to 10 hp. 5. G-E WATER COOLERS For commercial and industrial installations. Sanitary top; angle-stream, non-squirt bubbler; automatic stream regulator; sturdy, attractive cabinet; foot pedal control; sealed refriger ation system; economical pre-cooler. Three air-cooled pres sure type units--4, 7, and 10 gph; 10 gph water-cooled pressure type unit, and 3 gph bottle type cooler. 6. G-E CONDENSING UNITS AND COMPRESSOR UNITS For air conditioning, process cooling, refrigeration; for selfcontained or remote application. Open type units from % to 60 hp; sealed units from % to H bp. 1108 General Electric Air Conditioning Central Systems G-E HOME HEATING EQUIPMENT 7. G-E OIL FIRED BOILERS Compact, integral unit. Outstandingly economical. High heat transfer rate and low water content mean fast heat. Built-in tankless-type hot water coil available. Five models: 100,000 to 450,000 Btu's per hour. Listed by Underwriters' Laboratories, Inc. Constructed in accordance with ASME Code. 8. G-E OIL FIRED WARM AIR FURNACES Quick heat due to rugged steel, finned heat transfer surface. G-E engineered to retard chimney losses during shutdown. Four models:--60,000 to 155,000 Btu's per hour. Listed by Underwriters' Laboratories, Inc. Ideal for use in G-E AirWall or conventional warm air systems. For year 'round air conditioning, use in parallel with G-E Residential Air-Gondi- tioner. - 9. G-E GAS FIRED BOILERS G-E specially designed, water filled, diamond-shaped projec tions on cast iron boiler sections and unique zigzag flue gas travel--to assure rapid heat transfer and maximum heat ab sorption. Clean, quiet, complete combustion because of raised port atmospheric burners. Seven models--96,000 to 432,000 Btu's per hour. Tested and approved by the A.G.A. Listed by Underwriters' Laboratories, Inc., and constructed in accord ance with ASME Code. 10. G-E VERTICAL GAS FIRED WARM AIR FURNACE Rugged cast iron section with pin-point extended surfaces re . suit in high heat transfer. Automatic controls for dependable operation. Burns natural, manufactured, or mixed gas. Five models: 60,000 to 210,000 Btu's hr input. Tested and approved by A.G.A. Listed by U.L. Ideal for use in G-E Air Wall or conventional warm air systems. For year 'round air condition ing, use in parallel with G-E Residential Air Conditioner. 11. G-E AIR-WALL HEATING SYSTEM The amazing new system of distributing heat from standard G-E Gas or Oil Fired Furnaces. Two-types of heat in one-- forced warm air plus radiant heat. G-E standard Air-Wall Register directs heat in a fan-like pattern up and out in front of the normally cold walls of a room, warming them so that they actually radiate heat. G-E Automatic Air-Wall Register offers all these benefits plus automatic individual room temperalure control. Thermostat element in automatic register modulates damper to admit warm air required to each room. NEW PRODUCTS G-E Horizontal Gas Furnace is designed for installation in attic, crawl space, basement, utility room. It may be sus pended from rafters or floor joists to save floor space. This space-saver unit has all the famous G-E gas furnace features described above including the long-life, fast-acting pin-point heat transfer sec tions. Two models with 90,000 and 120, 000 Btu's hr input. Tested and ap proved by A.G.A. Listed by U.L. Ideal for use in G-E Air-Wall or conventional warm air systems. G-E Kitchen While Oil Boiler is a com pact, fully integrated unit, combining an oil-fired boiler, a built-in expansion tank, and a tankless-type hot water coil. De signed for radiant panel and forced hot water. Attractive white jacket stays comfortably cool. Oil burner listed by Underwriters' Laboratories, Inc. G-E Year 'Round Air Conditioning Sys tem combines the new G-E Residential Air Conditioner with the G-E Oil or Gas Fired Warm Air Furnaces. With these units connected in parallel, this system heats, cools, filters, humidifies, dehumidifies, ventilates, and circulates the air. The G-E Residential Air Conditioner can often be installed in existing warm air heating systems with only minor changes in ductwork. 1109 Air Conditioning Frigidaire Division of General Motors. Dayton 1, Ohio Room Air Conditioners--Self-Contained Air Conditioners--Central System Air Conditioners More railroad cars are air conditioned by Frigidaire i Boom Air Conditioner Room Air Conditioners Compact, easily installed window units, providing all five summer air conditioning functions for rooms up to 500 sq ft. 4-way cool air outlet, fresh air control, exhaust air control, moisture disposal. All-steel, heavy-gage welded cabinet, bonderized. Thermostatic control optional. Quiet operation. Powered by sealed-in Meter-Miser, with 5-Year Warranty. % and 1 hp self-contained units. Sdf-Con iained Air Conditioner Self-Contained Air Conditioners 3, 5, 7\, and 10 ton capacity self-contained units. Quickly installed, fast, low-cost cooling. Little or no duct work needed. Use singly, or in multiple for a wide range of applica tions. Welded steel construction. Centrifugal, double-width fans. Thermostatically controlled. Water-cooled compres sor, rubber-mounted for vibrationless operation. Uses safe Freon-12. Heating coil optional. Full Underwriters' ap proval. Central System Air Conditioner Hemv Duty Comprtam Central System Air Conditioners Both horizontal and vertical central system air conditioning models, in capacities, types and sizes to meet practically any air conditioning need. 5 to 40-ton capacities. Heating coils and humidifier assembly optional. Quiet, vibrationless opera tion :K Ball-bearing, oil-less type rubber-mounted motors. Aileron control adjusts air discharge. Frigidaire Multipath Cooling Units. Heavy-Duty Compressors. Water-cooled compressors, including 7| to 25 hp with stepcontrol for regulating capacity. Designed for properly bal anced operation with Frigidaire cooling units and controls. Precision manufacture reduces friction, drag, resistance to a minimum. Important features, such as long-wearing pistons, with floating piston pins, sealed crankcases, one-piece bodies, continuous lubrication. Evaporative Condensers . 10 to 60 ton capacities for use with evaporative type compressors. All steel rein forced cabinet, all surfaces fully protected from corrosion. Prime surface con denser coil, easily accessible. Low pressure, non-clogging spray nozzles. Frigidaire reserves the right to change specifications, or discontinue models without notice. 1110 Air Conditioning nStHefte5"d Coolers Hastings Air Conditioning Co., Inc. Hastings, Nebr, Manufacturers of - Cooling, Heating and Ventilating Equipment. Gas and Steam Unit Heaters. Water, DX and Steam Coils. 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; ' Floor Model* UTILITY MODELS: One or more units will handle any size job with or without ductwork. Attractively finished, these units are ideal for installation within the conditioned space. Four-way, stainless steel louver grilles are standard. CENTRAL PLANTS: Sectional construction for ease of handling. Motors mounted inside to provide neat, compact units. Angle-iron base frame for suspension is standard. Model Zephyr Royal Majestic Master Floormaster Type Suspended Floor model Suspended Suspended hloor model CFM 590 590 1,120 2,240 2.240 SPECIFICATIONS Capacity--tons Water 6 Row DX Motor 4 Row 6 Row HP Filters Coil Coil Coil 1-2 1-2 1)4-3 3-0 3-6 ___ -- 2)4 5 5 ___ -- -- -- -- <4 % H & H 1 1 2 4 3 Dimensions Height Width Depth 25" 24" 29" 40 28 21 26 28 38 27 46 48 93 48 25 CP 30 CP 40 CP 60 CP 80 CP 120 Suspended 3,000 4-9 m 10 1 5 30 51 60 Suspended 4,000 6-12 10 15 1 8 31 64 73 Suspended 6,000 9-18 15 20 2 10 31 70 74 Suspended 8,000 12-24 20 30 3 12 36 75 85 Suspended 12,000 18-36 30 40 5 20 39 95 90 STEAM UNIT HEATERS.--Centrifugal Type for extreme quietness and efficiency. Steam pressure--to 150 lbs per sq in. Finish--Brown wrinkle enamel and stainless steel louvers. Sizes--80,000 Btu/hr and 160,000 Btu/hr output. GAS UNIT HEATERS.--Twelve models. 75,000 to 200,000 Btu capacity. Equipped with CENTRIFUGAL or PRO PELLER type fans. A.G.A. approved for all gases. Squirrel-cage blowers provide SILENT operation and per mit air delivery thru duct systems up to in. S.P. Stainless steel ribbon burners result in quiet efficient com bustion. Dual directional, individually adjustable stainless steel louvers permit complete control of air delivery. Write for Catalogs, Literature, or Information 1111 i ' Air Conditioning -s^m Niagara Blower Company General Sales Office: 405 Lexington Ave. Hew York 17, N. Y. Chicago--5: 37 W. Van Buren St. ' Buffalo--7: 673 Ontario St. Seattle--4: 705'Lowman Bldg. District Engineers in Principal Cities Over 85 Years' Experience in Industrial Air Conditioning, Liquid Cooling and Air Drying 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 AIR CONDITIONING SYSTEMS For human comfort and for all industrial applications requiring controlled conditions of temperature, relative humidity, air purity and air movement. '1. ~ NIAGARA AIR CONDITIONER. TYPE A, AND CONTROLLED HUMIDITY METHOD 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 specific information. NIAGARA AIR CONDITIONER, TYPE C A year around air conditioning unit providing heating and humidifying or dehumidifymg. 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. 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. Ask for Bulletin 111. NIAGARA "DUAL"COOLERS Simultaneously cools a room and furnishes chilled water as a refrigerant. Saves equipment cost, operating expense. Patented. Ask for Bulletin 70. 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 73 and 109. NIAGARA MOTOR BLOWERS One, two and three-fan units. High and low static pressure models. Ask for Bulletin 89. 1112 Niagara Aeropaee Condenser with "Oilout" and Balanced Wet Bulb Control Air Conditioning unit System* Pittsburgh Lectrodryer Corporation Foot of 32nd Street Pittsburgh, 30, Pa. This machine protects equipment in storage by maintaining a relative humidity of SS per cent or lower. Small automatic air conditioning type LEC TRODRYER used for providing lowered rd- - alive humidities. FOR INDEPENDENT CONTROL OF DEHUMIDIFICATION IN COM FORT AND INDUSTRIAL AIR CONDITIONING The results of years o.' experience in the independent control of industrial de humidification are now available for com fort air conditioning in the form of sturdy, dependable, thoroughly tested 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 machines for controlled adsorption de chaser specifies. Standard machines are humidification. available in several sizes ranging from 350 cfm upward. 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 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. eration or water cooling. With this type Write for full details. 1113 Air Conditioning 1'Sems 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. 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 for 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. 1114 Air Conditioning Parks-Cramer Company Fitchburg, Mass. Charlotte, N. C. Automatic Airchanger An improved system of forced air change and distribution used with a direct humidifying system. Insures fixed humidity and maximum evaporative cooling by controlling amount of air change and operation of humidifiers by humidity and temperature Psychrostat. Designed for either complete new in stallations or for supplementing existing direct humidifying equipment. Gradumatic Humidifying System New and advanced 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. Few component parts, easy to take apart and reassemble. Proper operation assured without testing. No adjustment re quired. Both air and water ports cleaned automatically. Heads operate continuously, evaporative output being varied gradually and automatically by Certified Climate Psychrostat to suit requirements for constant humidity at all times. Certified Climate Psychrostat Improved model more sensitive and accurate than ever before. Rugged and reliable. Use of the wet and dry bulb principle permits Psychrostat to perform the many and varied tasks in the field of humidity and temperature control which con tribute 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. 1115 Air Conditioning United States Air Conditioning Corporation Engineers and Manufacturers of Air Conditioning, Refrigeration, Units Heaters, Coils and Ventilating Equipment 3321 Como Ave. Southeast For Industrial, Commercial and Residential Applications Minneapolis 14, Minnesota Refrigerated Kooler-aire--Central Sta tion Air Conditioning plant with builtin evaporative condenser or water con denser. 3 to SO ton 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 tonB. Permits water savings of 95 per cent. Upright Store Conditioners--A com pletely packaged room air conditioner built in: 2,3, 5, 7l/t and 10 ton capacities. Room Air Conditioner--One-half ton and three-quarter ton window type air conditioners with five year compressor guarantee. 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. 1116 Central Systems, Air Conditioning Refrigeration and Unit Heaters Westinghouse Electric Corporation Air Conditioning Division Air Conditioning, Heating, Ventilating, Refrigeration Compressors, Dust Control and Fume Removal Equipment, Electronic Air Cleaners, Mechanical Draft Equip ment Hyde Pflik offices in aii principal cities Boston 36, Mass, AIR CONDITIONING UNITS Unitaire Conditioners (R) are complete self-contained easily installed air con ditioning units requiring 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 and 8 tons. Type LU Central Plant Unitaire Con ditioners are designed for installation with supply and return air ducts and are available in capacities of 10, 15, 20 and 25 tons. 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 Self-Contained Unitaire Type S U Central Plant Unitaire Type L U Compressor. Type CLSlStQ I&TER COOLED CONDENSERS Available in 14 sizes within the 2 to 100 ton range. Constructed with integrally finned copper tubing and steel shells and tube sheets in accordance with the recommendations of Paragraph U-69 of the ASME Unfired Pressure Vessel Code. WATER COOLERS Type LC Water Coolers are vertical semi-flooded, Freon-12 Units designed for cooling water for use in indirect air conditioning systems and industrial processes. Available in 5 sizes with ca pacities from 5 to 110 tons. EVAPORATIVE CONDENSERS Where water is scarce or expensive, or its use or disposal restricted, Evapora tive Condensers provide savings in water consumption. Available from approxi mately 5 tons to 100 tons of refrigeration. UNIT HEATERS - Sturtevant horizontal Speedheaters-- available in capacities of 25,800 to 300, 500 Btu/hr for both steam and hot water applications. Downblast Unit Heaters project heated air downward to working level. Avail able in capacities of 40,000 to 400,000 Btu for both steam and hot water ap plications. Type CWC Two-Cylinder V-Type Com pressor. Type CLS 110/188 Water Coder Type LC Aqyamiser Evaporative Condenser--Type EVA Downblast Speedheater Design It Horizontal Speedheater Design 14 1117 Air Conditioning central Sjstmmi Worthington Pump and Machinery Corporation Air Conditioning and Refrigeration Division General Offices: HARRISON. NEW JERSEY Albany Atlanta Baltimore Birmingham Boston BuYyalo CHARLOTTE Chicago Cincinnati Cleveland Dallas Denver Detroit El Paso FobtWobth Louisville Galveston Milwaukee Greenville, S-C. New Haven Houston New Orleans Kansas Citt New Yore Knoxville Omaha . Los Angeles Philadelphia Phoenix Pittsburgh Portland, Orb. Providence St. Louis Sr. Paul Salt Lass Cm Representatives'In all Principal Cities San Franobco Seattle Springfield, Mass. Syracuse Tulba Washington, D. C. Wilmington, Del. AjO.25 Packaged Air Conditioners Centrifugal Refrigeration Water Codling Systems Provide cooling (or heating, if desired), dehumidification, ventilation, and air cleaning for commercial and industrial applications. 3, 5, 71, 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. Refrigeration Compressors Freon Air Conditioning Units Model HS-3 and 5 hp, 2-cylinder, vertical, splash lubrication. Model HF 7J to 100 hp, 4-cylinder, B-type and 6cylinder, W-type; full force feed lubri cation. 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. 5 sizes, 2,000 to 12,000 cfm, 4 to 62 tons. With or without internal face and bypass damp ers. Series ECZ, 10 to 150 tons. Sectionalized construction, all parts easily ac cessible. Galvanized steel coils for am monia, bare copper coils for Freon-12. 1118 Air Conditioning York Corporation York, Pennsylvania Factory Branches and Distributor 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 available over wide range of capacities--up to 1500 tons refrigeration for Freon-11 water cooling duty--suitable for steam turbine or motor drive. Self-contained dynamically balanced, non-vibrating V/W type reciprocating com pressors available in capacities up to 350 tons refrigeration in a single unit, with water cooled or economizer type condensers. Efficient automatic capacity reduction available for economical operation at reduced load. York Sectional Economizer The York Economizer--A combined force-draft cooling tower and refrigerant con denser, 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 Bingly or in multiple for applications of any specified capacity. Economizers 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, for year-round processing. Yorkalre Unit Air Conditioner--A compact, self-contained model occupying but 21 x 42 inches of floor space and requiring only water, drain and electrical connections to operate. Spe cial 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-^-ap, 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 Yorkaire Unit Air Conditioner 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 espe cially applicable. Construction features insure a minimum space demand and maximum performance conditions. Stand ard washers are available in a full range of capacities for industrial installation. 1119 Air Conditioning Automatic Heating Air Control American Foundry and Furnace Co. Auburn, Ind. Chicago Cincinnati Cleveland Dallas, Tex. Denver Dee Moines Detroit, Mich. Elmira, N. Y. Ft. Worth, Tex. Grand Rapids Indianapolis Kftnaafl City, Mo. Kenmore, N. Y. Los Angeles General Offices: Bloomington, Illinois P. O. Box 904 Sales & Engineering Offices in Principal Cities Lige Warm. A Vent. Co. Temperature Equip. Corp. Walter A. Juergens Amex. Warm. A Vent. Co. J. F. Ashcraft Co. Kent Engineering Co. C. H. McGuiness Co. H. J. Clemens Amer. Warm. & Vent. Co. J. P. Ashcraft Co. Bennett Heating Equip. Co. Elliott-Williams Company John H. Kitchen A Co. Murton J. Rodman Harry F. Haldeman, Inc. Milwaukee Nashville . New Orleans New York City Oakland Philadelphia Richmond, Ind. Richmond, Va. St. Louis Salt Lake City San Antonio Seattle Toledo West Lafayette, Ind. Amer. Fdry. & Fur. Co. Cooper A Winters R. K. Rothrock The Demutb Co. Aladdin Heating Corp. Amer. Htg. & Vent. Co Harry Hoff SM. Works Richmond Air Eq. Co. M. F. Carlock Williams Gritton A Wilde Langhammer-Rumrnel Co. McPherson Fur. A Eq. Co. Amer.Warm. A Vent. Co. F. H. Speaker A Son F-12 LOUVER DAMPER Made to fit any size opening. Adaptable to automatic or hand control. Blades of 16 gage steel. Channel frames 2 x 34 x 34 in. standard except in large sizes-- optional 34 x 2 in. bar iron frame. Stand ard steel painted aluminum--optional galvanized iron. Ball bearing blade piv ots standard--optional brass trunions. Made for. vertical or horizontal installa tion. For industrial plants, power houses, hotels, schools, theatres, etc. When F-12 is ordered with blades longer than 48 inches, dampers are made in multiple sections operating in unison. Motor brackets for internal or external mounting at extra charge. Motors and connecting linkage furnished by others unless specific arrangements are made. Standard is as illustrated with adjustable extended shaft. . S-454-F COMBINATION STORMPROOF LOUVER and DAMPER Consists of galvanized iron frame with 26 gage galvanized iron stationary horizontal stormproof louver blades riveted se curely to outside frame. Apron extends over sill. Back of stormproof louver is No. 16 mesh, rust-proofed, insect screen in "U" type removable frame. Back of screen is multipleblade ball nearing louver damper--similar to F-12 but with off-center axle--to control volume of air admitted. Louver damper blades of 16 gage steel galvanized. Frame of 2 x 34 x ^ in. galvanized channel iron. Dampers can be automati cally or manually controlled. Blades all work in unison. Made to fit opening size specified. Standard for 8 in. deep wall. Entire assembly or any part can be furnished made of aluminum, copper or stainless. SUPERIOR BLOWERS Forwardly Curved Multiblade Type Heavy Duty Construction Made in Single and Double Widths with wheel diameters ranging from 10 to 65 in., in 5 in. increments. Capacity Range: 800 to 105,000 cfm 1120 American Foundry and Furnace Co. Air Conditioning t Automatic Heating Air Control HEAVY DUTY HORIZONTAL HEATERS Heavy Cast Iron Construction for long, dependable service and steadier heating even with automatic burners. Sectional for easy conveyance, assembly, and part replacement. Tight Joints--offset type packed with furnace cement and asbestos rope, then bolted. Integrally Cast Fins add strength and heating surface. Long Fire Travel saves heat and fuel. De signed to Relieve Internal Stresses set up by heating and cooling. No Freezing-- No Scaling of heater possible since no water used to transfer heat. Att active Steel Panel Casing. CENTRAL TYPE FORCED WARM AIR For schools, churches, theatres, audi toriums, gyms, drying plants, etc. Heats and ventilates with same system --uses part outside air to maintain air quality. Air filters, automatically con trolled humidifier, and automatic tem perature regulation optional. Summer cooling by adding compressor and coil. Output Capacity per heater, Btu per hr: Hand Fired Coal-- Stoker Fired 278,000 to 1,942,000 Coal-- 278,000 to 2,440,000 Oil or Gas-- 278,000 to 4,080,000 Two or more heaters may be set to gether to provide any desired output capacity. Special Models for hand fired coal, stoker fired coal, oil and gas. Convertible Heater (see picture top of page) designed so only minor changes necessary to switch from use of one fuel to another at any time and yet preserve same output capacity--a distinct advan tage when fuel situation uncertain. UNIT HEATER TYPE FORCED WARM AIR For Industrial Buildings, Warehouses, Factories, etc. For oil, gas or stoker fired coal. Use for heating and ventilat- mg, or for tempering outside air supplied to replace air exhausted. Each unit is complete heating plant. Induced Draft Fan optional. Output Capacity. Range Eer Unit: toker Fired Coal - 557,500 to 2,028,000 Btu per hr. Oil or Gas - 440,000 to 3,580,000 Btu per hr. DOMESTIC HEATING EQUIPMENT 1121 June-Aire Vertical Gat Fired Air Conditioning ' ~ ~1 American Furnace Co. 1300 Hampton Ava, St Louis 10, Mo. Factory-Red Bud, 111. Home Office--St. Louis, Mo. Manufacturers of Warm Air Heating Equipment Distribution and Sales Offices in Principal Cities GAS - OIL - COAL FIRED HEATING UNITS " ----- SPACE HEATERS--Suspended ceiling units for industrial and commercial instal lations--oil or gas fired. Space saving automatic heat--no furnace room needed. Functions effectively with minimum of duct work. Ratings up to 210,000 Btu output. Two sizes--oil input 1.35 gph and 2 gph. Unit Heater AGA approved--Gas fired--vented-- propeller fan forced air type mod ernly styled, die-formed, welded steel cabinet--baked hammerloid finish. Heat ex change elements hidden from view and touch. Fan securely mounted at rear. Btu input, 90,000 and 150,000 per hour--air delivery cfm--1400 and 2300. GAS FIRED UNITS--A.G.A. approved gravity, forced air, Base-Bio (hi-boy) and Counter-Flo models. Heat exchanger in Master Gas models--electrically welded steel--In Thermo design--sectional cast iron. Nationally known controls, dou ble walled Hammerloid enamel finished cabinets. Hourly Btu input ratings, 70.000 to 200,000. 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 UNITS--Gravity, hi-boy, Counter-Flo and forced air models-- Oil Master, Vapor-Fire and Air Stream designs. . 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 gal per hour. SOLID FUEL UNITS--AFCO gravity steel furnaces and THERMO gravity cast iron furnaces--Thermo pipeless cast iron and AFCO Modern Air (forced air) steel units. Gravity units available in conventional round galvanized casing or in square cabinet finished in two-toned Hammerloid enamel. All units adapt able to automatic heat with gas, oil, or stoker. Btu capacity at registers up to 236.000 per hour. Stoker--"Triple Seal" construction eliminates hopper smoke nuisance. Three sizes 20, 35 and 50 lb coal feed per hour. Capacity up to 480.000 Btu per hour. Descriptive Bulletin Available on each Uoid 100 Serin UA Unit. 1122 Air Conditioning SdFintoS' Clayton & Lambert Mfg. Co. Louisville 10, Ky. Manufacturers of C & L Blow Torches, HOFFMAN Water Heaters Silver Shield Silos, LAMNECK Furnace Pipe and Fittings dom from exposed ducts in recreation rooms, etc. Flexibility, ease of assem bly, reasonable original cost, efficiency and accurate control of air flow, com bined with exceptional appearance, are inherent qualities of this DeLuxe System. 720-T Main Trunk Ells, sizes same as - duct 721 Side Takeoffs 4x8, 5x8, 6x8 722 Side Takeoffs 4x8, 5x8, 6x8 724-725-726 Reverse Stack Elbows 700-T Duct sizes 4x8 to 36x8 710-T Starting Collar, sizes same as duct 728-T & 729-T Increaser-Reducer Sections, sizes same as duct (Max. Inc. 10" for 728-T and 5' for 729-T) 712-T Main Trunk Angles, sizes same as duct 713-T Main Trunk Angles, sizes same as duct 717-T Main Trunk Ells, sizes same as duct 730 735 712 713 716 717 720 700 755 756 Top . Takeoff 4x8-10x334, 5x812x3)4, 6x8-14x3)4 Stack Adapter 4x8-10x3)4, 5x812x3)4, 6x8-14x3)4 Angle 10x3)4, 12x3)4, 14x3)4 Angle 10x3)4, 12x3)4, 14x3)4 Elbow 10x3)4, 12x3)4, 14x3)4 Elbow 10x3)4, 12x3)4, 14x3)4 Elbow 10x3)4, 12x3)4, 14x3)4 Wall Stack 10x3)4, 12x3)4,14x3)4 Stack Head 4, 5, 6, 8x10, 4, 5, 6, 8x12, 4, 5, 6, 8x14 Stack Head 4, 5, 6, 8x10, 4, 5, 6, 8x12, 4, 5, 6, 8x14 Write for L-49 Catalog showing our complete line of Standardized Ducts and Fittings. j 1123 / Air Conditioning STTM Campbell Heating Company 3121 Dean, Des Moines 17, Iowa ' SUMMER and WINTER AIR CONDITIONING Industrial, Commercial--Institutions, Residences Eabtebn Representative: Neil Adams, Old York Road, Lambertville, N. J., Telephone No. 665 CAMPBELL "WINTER-CHASER" AIR CONDITIONING SYSTEM The Campbell "Winter-Chaser" System provides all the essentials of winter air conditioning: Simultaneous control of temperature, humidity, air circulation and air cleanliness, besides providing fresh air for ventilation, quick heating, flexibility; and a summer cooling effect. Campbell equipment is built of the best materials obtain able, and has been developed through over sixty years of experience. The system is designed by competent experienced engineers and installed by experienced mechanics. It is guaranteed as to results and for 10 years as to durability. We will be glad to help solve any heating or ventilating problems or help with layouts and specifications for churches, schools, garages, etc. For Large Schools, Churches, Commercial and Industrial Buildings GAS--OIL--STOKER OR HAND FIRED Campbell Heating Company Air Conditioning Automatic Equipment Heavy Duty Furnaces CAMPBELL "WINTER-CHASER" AIR CONDITIONING SYSTEM ENGINEERING SERVICE Our Engineering Department will be glad to help solve any heating or ventilating >roblems or help with layouts and specifications for churches, schools, or any large milding. GUARANTEE If the duct system is designed or approved by our Engineering Department, and heater and blower are furnished by us and are according to our ratings, we will guaran tee any heater for ten years against repairs from any cause and will guarantee the heating of all rooms to which warm air is delivered to 70 deg in the coldest and wind iest weather. The motor, humidifier, automatic burner and controls, and other parts made by others carry their manufacturers' guarantee. GAS OR OIL FIRED 8000 Series Heater No. 8075 8100 8125 8150 8175 8200 8250 Output Capacity BTU Per Hr (1) Heating Normal Surface Blower CFM Sq Ft for 140 (2) Reg. Temp. Size Motor for yr sp HP 725,000 280 8,850 893,000 320 10,900 1,080,000 360 13,200 1,275,000 440 15,600 1,440,000 480 17,500 1,725,000 600 21,100 2,160,000 750 26.400 1 in 2 2 2 3 Dimensions Casing Inches 76 x 80- 88* high 76 x 93- 96* 3 76 x 105- 96* " 76 x 118-102* " 76 x 130-102* " 94 x 137-120* " 94 x 157-120* " Addnl Space for Blower 54* 60* 66* 66* 72* 76* 76* Approx. ShippingWeight Including Burner & Comb. Chamber, lbs. 6,000 7,200 8,500 9,700 11,500 12,700 15,000 I Unit includes furnace, casing, blower, motor. V-flat drive. (1) Allow 10 to 35 per cent over beat loss figures for pick up load and 10 to 15 per cent for duct and other radiation losses. The upper hgures are preferable for best operating economy and life of the equipment. (2) Heat emission per sq ft of heating surface is 3000 Btu per hr or less. 1124 Unit No. I CFM Output at Heating for 140 Registers Surface Regis* Btu per hr. Sq Ft ter _________I Temp. Motor Size for H SP HP Gals. Oil Gas or Oil No. of Filters Casing Size, Inches Approx. Input. | and Size, ABtu per hr. j inches j L | W I Ht. 1866 18100 27133 30166 30200 302^ 30250 For residences, stores and other buildings kept warm continuously (1) 112,000 (3) 66 1400 w 1 140,000 4-16 x 20 78 41 168.000 100 2100 a 1M 210,000 4-20 x 20 86 41 224,000 133 2800 V, 2 280,000 6-16 x 25 90 50 280,000 166 3500 w 350,000 6-16 x 25 92 60 336,000 200 4200 3 420,000 9-16 x 25 97 60 392,000 233 5000 H 3H 490,000 12-20 x 20 104 80 448,000 250 5600 a 4 560,000 12-20 x 20 104 80 52 57 62M 74 . 76 72 72 1300 1700 2100 2600 3100 3500 3700 133D 1MD 200D 233D 250D 255D For churches, schools or buildings where rapid temperature raising is necessary (2) 290,000 (4) 133 3700 X 3 365,000 6-16 x 25 90 50 62H 365,000 166 4600 X 3X 455,000 6-16 x 25 92 60 74 440,000 200 5500 X 4 550,000 9-16 x 25 97 60 76 510,000 233 6400 V, 4H 635,000 12-20 x 20 104 80 72 580,000 250 7300 y* 5X 730,000 12-20 x 20 104 80 72 660,000 255 8300 6 820,000 12-20 x 20 104 80 72 2100 2700 3200 3600 3800 4000 Campbell heaters are guaranteed to deliver full rated capacity C) AI]W approximately 10 per cent over heat loss for pick up load. W Allow uj> to 35 per cent over heat loss for pick up load. Meat emission per sqft of heating surface is 1800 Btu per hr or less. (4) Heat emission per sqft of heating surface is 2600 Btu per hr or less. 5^pTOR, EASTERN SALES: Neil Adams, Old York Road, Lambertville, N. J. Telephone 1125 Air Conditioning Automatic Equipment; Heating and Cooling CHRYSLER AIRTEMP AIRTEMP DIVISION OF CHRYSLER CORPORATION. DAYTON L.OHIO "PACKAGED" AIR CONDITIONERS 2-, 3-, 6-, 8-, 11- and 16-ton capacities COMPLETE--Assembled and tested at the factory. Cools, dehumidifies, filters and circulates air. Free air discharge or duct distribution. Heating coil for year-'round service optional. COMPACT--Entire unit is enclosed in "Bonderized" steel cabinet of modern 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. 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) one hp. unit requires 230 volts. Adjustable grilles provide controlled air circulation. Adjustable outside air intake. Cooling, mechanism can be turned, off for mild weather air circulation. . DEHUMIDIFIERS }-hp Capacity. Low-cost, portable dehu midifier removes excessive moisture from the air. Can be plugged into any convenient electrical outlet. Protects against rust, mildew and corrosion. Very compact in Bize--15 in. high, 12 in. wide, 16J4 in. long. RADIAL COMPRESSOR UNITS 10 to 100-ton 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. Seven models in three types-- floor, wall and ceiling--are available. Built-in controls make: each unit independently operated. Two centrifugal fans pro vide circulation. COMMERCIAL REFRIGERATION UNITS For refrigerator cases, cooler rooms, walk-in boxes and other commercial applications. Sealed and open types for self-contained or re mote installation. Complete range of sizes from hp to hp. 1126 Air Conditioning Heann* CHRYSLER # AIRTEMP AUTOMATIC HOME HEATING CHRYSLER AIRTEMP AUTOMATIC HOME HEATING GAS-FIRED FURNACE GRAVITY____ Sheet steel cabinet, "Bonderized" inside and out to resist rust. Heating surface is surrounded by an inner liner. Cooler air circulation between this and cabinet provides minimum heat loss. Burner is adap table to all gases . . . gives quiet operation . . . and is easily removed . for service. Complete with automatic controls. Capacity: 80,000 Btu. . CONVERSION GAS BURNERS. . . .For quick, easy installa tion in existing furnaces. Combustion principle provides higher efficiency . . . minimum fuel consumption. Available in two capacities from 75,000 to 225,000 Btu. CONVERSION OIL BURNERS. . . .New focused flame design. Four models available in capacities from 34 gal to 4J4 gph. New type high velocity firing head secures exceptional effi ciency, clean and quiet operation with both straight run and catalytic oils. GAS-FIRED AUTOMATIC FURNACE____ Heats, humidifies, filters and circulates the air. Steel Models 60,000 to 185,000 Btu output. "Bonderized" and insulated jacket. The Airtemp Gas Burner starts, stops and operates quietly, has many exclusive features -- no popping or flash-backs. Approved, A.G.A. Laboratories. OIL-FIRED STEEL BOILERS____ 12 models--from 81,000 to 324,000 Btu--for steam and hot water heating in every size and type of home. Available in flush and fully enclosed types, complete with Airtemp burner and all controls. COMBINATION HEATING AND COOLING FOR THE HOME. . . .Combination of a 2-ton, 3-ton, 5-ton or 8-ton Chrysler Airtemp "Packaged" Air Conditioner and any of the larger Chrysler Airtemp automatic furnaces. The same blower, filters and ducts of the automatic heating system are employed for cooling in the summer. 1127 Air Conditioning Automatic Equipment Gas Fired Units Hayes Furnace Mfg. & Supply Go. 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 coolmg coils or washer. Heat exchanger will not corrode when subjected to continuous ventilation dunngthesummerseason. Designedfor 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 7O;0OO.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. Suspended 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.G-A. APPROVED 1128 Air Conditioning SdrSraaces Syncromatic Corporation Watertown, Wisconsin HEAVY DUTY STEEL FURNACES OIL -- GAS -- COAL 330,000 to 1,000,000 BTU Output MANUFACTURERS OF WARM AIR HEAT ING EQUIPMENT DISTRIBUTED THROUGH RECOGNIZED WARM AIR WHOLESALERS IN PRINCIPAL CITIES 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. H.P. BLOWER MOTOR SMOKE OUTLET MODEL NUMBEH B.T.U. OUTPUT AT BONNET CFM AT 2" EXT. 8T. PR. OFB 33 OFB 40 OFB 45 OFB 50 OFB 55 OFB 60 OFB 70 OFB 80 OFB DO OFB 100 330,000 400,000 450,000 500,000 550,000 600.000 700,000 800,000 900,000 1,000,000 4,000 4,850 5,800 5,800 6,800 7,500 8,500 10,000 11,500 13,500 1.0 1.0 1.5 1.5 2.0 2.0 2.0 3.0 3.0 3.0 DIMENSIONS L wH 531 102' 72" 63{ 102* 72" 53* 102* 72" 67J 110* 72" 671 no* 72" 671 110* 72" 811 118' 84" 811 118* 84" 651 132* 84" 951 132' 84" FIRING RATES 1000 APPROX. OIL B.T.U. BTOKEB SHIPPING G.P.H. GAS lb/hb WEIGHT GF.H. 12" 3.0 12" 3.5 12" 4.0 14" 4.5 14" 5.0 14" 5.5 16" 7.0 16" 8.0 18" 9.0 18" 10.0 393 476 534 595 655 715 835 950 1075 1145 35 4180 0 40 4180 0 45 42300 50 4884$ 55 4934 60 4934 70 6357 80 6617 90 7367 100 7517 CP-Coal Fired Gravity & Forced 70 to 160,000 Btu "700" SERIES OFB 611 OR- OQ-Fired Fired Hl-BOY 00 to 146,000 Btu 86,000 Btu GPU Gas Fired HI-BOY 76 & 66,000 Btu GF Gat Fired "000" Series LO-BOY OR Fired 76 to 146,000 Btu 80 to 108,000 Btu Complete line of warm-air furnaces for residential heating in Gas, Oil and Coal, - using Patented Counter Flow heat exchanger principle Complete range of ratings from 60,000 to250,000 Btu output. Separate catalogs on all of the above units are available on request. For complete information on Hi-Cap line write to: SYNCROMATIC CORPORATION, Watertown, Wisconsin. 1129 Air Conditioning Thg ffleveR fuRnace Comppnv Peoria, Illinois ' Branches*and Distributors --... Manufacturers of Heating and Air Conditioning Equipment ' for Coal* Gas and . Oil Burning Atlanta, Ga. Chicago,'III. Kansas Crrr, Mo. Minneapolis, Minn. Baltimore, Md. Columbus, O. Knoxville, Tenn. Muscatine, Ia. Birmingham, At-*- Des Moines, Ia. Lima, O. Omaha, Nebr. Bosi-on, Mass. Florence, 8. C. Los Angeles, Calif. Philadelphia, Pa. Buffalo, N. Y. Grand Rapids, Mich. Milwaukee, Wis. Pittsburgh, Pa. St. Louis, Ma (Export Agent: Mid-States Export-Import Co., Inc., Peoria, 111.) WEIR AND MEYER Steel Warm-Air Furnaces have a more than 80-year reputation for efficiency, dependability and durability. They are available for small and large requirements and for all fuels in a wide variety of firing applications. MEYER GAS-FIRED EQUIPMENT--The MEYER gas-fired equipment is available in three types, the Q, M, the G Series ranging from 75,000 to 495,000 Btu/hr inputs. This entire gas line is A.G-A. approved. Q Series Q SERIES GRAVITY gas-fired equip ment is available in three sizes ranging from 75,000 to 150,000 Btu/hr. These units feature an extra large heating ele' ment and a Meyer fountain burner which produce amazing fuel economies. G SERIES FORCED AIR gas-fired is available in five sizes ranging from 110, 000 to 495,000 Btu/hr inputs. These units employ extra heavy gage heating elements of the tubular design, which extract maximum heat from the fuel used. M SERIES FORCED AIR gas-fired Hi- boy has an input of 90,000 Btu/hr. It is designed to furnish winter air condition ing for those who want to save space in their small homes. . U Series B-l SERIES FORCED AIR gas-fired LoBoy has an input of 110,000 Btu/hr and features the exclusive Meyer D-shaped Thermatic Radiator. Unit is shipped assembled. B-l Seria MEYER BLO-AIRE--These blower and filter units enable you to convert almost any gravity installation to forced air. They can be used for gas, oil, stoker, or hand-fired furnaces. Avail able in four sizes ranging from 1,000 to 2,600 cfm air delivery. MEYER SUMMER AIR CONDITIONER--MEYER Home Summer Air Conditioners are designed to fit neatly to the fan compartments of both oil and gas fired Meyer equipment. Available in 2, 3, 5, 6, 8 and 10 ton sizes these units are easy to install, and inexpensive to operate. They may be installed at the same time the heating equipment is installed or later. 1130 The Meyer Furnace Co. Air Conditioning iwffiffi.ffi.11'*11* MEYER OIL-FIRED EQUIPMENT.--The MEYER oil-fired air conditioners are available in four types, the D, B, E and K series ranging from 72,500 to 294,000 Btu.hr output at bonnet. The D and B Series are Hi-boys suitable for basement or first floor installation, and the E and K are designed for basement installations. D SERIES FORCED AIR--oil fired Hi-boy has an output at the bonnet of 72,500 Btu/hr. This unit uses an Underwriters' Laboratory approved burner of the vaporizing type. Designed for small homes this unit is compact and smartly styled. B SERIES FORCED AIR oil-fired Hi-boys are available in two sizes, 93,500 and 110,000 Btu/hr output at bonnet. These units use the high-pressure gun-type oil burner. D Series B-l SERIES FORCED AIR oil-fired LoBoy is available with pressure oil burner and output at bonnet of 105,000 Btu/hr or with vaporizing oil burner and output at bonnet of 96,000 Btu/hr. This series features D-shaped Thermatic Radiator. Unit is shipped assembled. B Series B-l Series E SERIES FORCED AIR oil-fired equip ment is available in two sizes, 110,000 and 165,000 Btu/hr output at bonnet. These units employ extra heavy gage heating elements of the tubular design, which extract maximum heat from the fuel used. K SERIES FORCED AIR oil-fired equip ment is available in two sizes, 203,000 and 294,000 Btu/hr output at bonnet. These units are designed primarily for larger homes and buildings. B Series WEIR COAL-FIRED EQUIPMENT--WEIR coal-fired equipment is available in four types: the U, UC, R and 500 Series, ranging from 81,000 to 1,000,000 Btu/hr output at bonnet. Multiple installations will produce greater outputs*. Welded and riv eted construction is rugged, efficient and gas-tight. Equipment may be stokerfired or adapted to oil or gas firing. U SERIES GRAVITY coal-fired furnaces are available in five sizes ranging from 91,300 to 170,000 Btu/hr output at bon net. U Series UC SERIES FORCED AIR coal-fired furnaces are available in five sizes rang ing from 81,000 to 191,000 Btu/hr output at bonnet. R SERIES HEAVY DUTY coal-fired fur naces are available as forced air units in two sizes with maximum, outputs at bon net of 400,000 and 500,000 Btu/hr. The 400,000 Btu/hr unit is also available as a gravity unit. This equipment is avail able in round or rectangular casings. UC Series B Series 500 SERIES HEAVY DUTY coal-fired, forced air furnaces are available in five sizes ranging from 550,000 to 1,000,000 Btu/hr output at bonnet. 1131 900 8eries _______________________________ / - Air Conditioning L. J. Mueller Furnace Co. - Milwaukee 15, wis. Mueller ClimafrolHEATING MR CONDITIONING Type 101 (Gas) 201 (Oil) Gas-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 103 Gas-fired, steel, winter air-conditioner. Sectional construction. 8 sizes (in 45,000 Btu increments) with A.G.A. input ratings from 225,000 to 540,000 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 hour. Type 110 Type 108 Gas-fired, cast-iron winter air-conditioner. Sectional construction. Available in 67,500, 90,000, 112,500, 135,000 and 157,500 Btu input. Type 109 (Gas) 209 (Oil) Gas-fired, steel, winter air-conditioner (convertible to, or available as oil-fired, Type 209). Two sizes: A.G.A. input ratings of 100,000 or 135,000 Btu per hour. Type 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, 100,000, 120,000and 160,000 Btu per hour. L. J. Mueller.Furnace Co. Air Conditioning Automatic Equipment; Heating--Cooling Type 115 (Goa) and SIS (Oil) Type ISO Type 1S5-151 Type 115 (Gas) and 215 (Oil) Gas-fired, steel, winter air-conditioner (convertible to, or available as oil-fired Type 215). Counter flow design for perimeter heating, slab or crawl-space homes. A.G.A. rated at 110,000 Btu input. Type 150 Gas, direct-fired, steel, suspended unit heater. Horizontal tubular design. Propeller-type fan. (Also with blower, Type 151.) Available with A.G.A. input ratings of 60,(XX), 90,000, 120,000 or 150,000 Btu per hour. Type 165-151 Gas-fired horizontal winter air-conditioner. Heat exchanger as in Type 150 with blower. Two sizes with A.G.A. input ratings of 60,000 and 90,000 Btu per hour. Type 151 Blower unit heater available in four sizes 60,000, 90,000, 120,000 and 150,000. Also, Type 253 oil-fired horizontal winter air conditioner. Type VH Type 10 Type SO Type UH Gas-fired unit-heater. Steel sectional design heat exchanger with in dividual burners. Nine sizes (45,000 Btu increments) with A.G.A. input ratings from 180,000 to 540,000 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 20 Gas-fired, cast-iron boiler for larger installations. Sectional construc tion (sizes increase in increments of 63,000 Btu). A.G.A. approved. Ratings of 1680 to 20,160 sq ft for hot water, and 1050 to 12,600 sq ft for steam. Type 111 ((7a) and Sit (Oil) Type US (paa) and SIS (OH) Type 114 (Gat) and S14 (Oil) Type 111 (Gas) and 211 (Oil) Gas-fired, steel gravity furnace. Available as, or convertible to oil-fired, Type 211. Shipped assembled. Available with A.G.A. input rating of 90,000 Btu per hour. Type 112 (gas) and 212 (Oil) Gas-fired, steel, winter air-conditioner (convertible 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-conditioner (convertible to, or available as oil-fired. Type 214). One size: A.G.A. input rating of 110,000 Btu. 1132 , Type SO Type 70S Type 901 type 50 Oil-fired, steel, winter air-conditioner. All-welded heat exchanger. Blower at rear. Pressure-atomizing burner. Available in four sizes with register output of 100,000, 150,000, 200,000 and 225,000 Btu output per hour. Type 702 Coal-fired, steel, winter air-conditioner. Blower-filter cabinet may be installed on either side. Five sizes--20, 22, 24, 27 and 30 inches. (Gravity unit in same sizes, Type 701. Cast-iron gravity and forced air also available.) Type 901 Summer air-conditioner available in 3-, 5- and 7-1/2 tons sizes. Shown installed in Type 105 gas-fired furnace which has A.G.A. inputs of 100,000, 150,000, 180,000 and 225,000 Btu. 1133  ' ' . Air Conditioning |n*?lSnent- Norge Heat Division of Borg-Warner Corp 672 E. Woodbridge, Detroit 26, Michigan Shown here are pictures and brief de scriptions of Norge Heat Products. More complete information ' on these products may be obtained by writing to Norge Heat Division, Borg-Wamer Corporation, 672 E. Woodbridge, De troit 26, Michigan. Gas Lo-Boy Models Gas Hi-Boy Models Fully automatic winter air conditioners for any gas--natural, mixed, manufac tured, L.P., L-P.-Air. Vee-Sectional 12gage steel heat exchanger with cleanout opening. Factory assembled. A.G.A. approved. 7 models, 80-170 M/Btu. Compact winter air conditioners for any gas. Built-in draft diverter; filter frames for returns. Vee-Sectional 12-gage steel heat exchanger. Factory assembled. Also Hi-Boy wall-type. A.GA. ap proved. 6 models, 62.5-120 M/Btu. Gas Gravity Models Gas Stowaway Models Fully automatic, easily installed. Drilled raised-port cast-iron burnerswith over 300 drilled jets provide cone-shaped flame. Round combustion chamber, baffled outer drum radiator. A.G.A. approved. 3 models, 80-120 M/Btu. Compact forced-air units. Pressedsteel plate-type heat exchanger. Non clogging, milled-slot,. cast-iron burners. Sirocco-type blower. Dual flue outlets. Factory assembled and wired. A.GJL. approved. 3 models, 60-100 M/Btu. Oil Lo-Boy Models Oil Hi-Boy Models Norge Heat, Div. of Borg-Warner Corp. Air Conditioning Oil Gravity Models Oil Suspended Models Fully automatic pressure-atomizing units. All-steel vertical combustion chamber, baffled outer-drum radiators. Pressure vaporizing and natural-draft floor furnaces available. Thermostat or manual...operation. 4 models, 54-100 M/Btu. ' Horizontal winter air conditioners. May be installed on attic floor joists, suspended from rafters or overhead joists. Pressure atomizing burner; cor rugated plate-type heat exchanger. Tunnel firing. 5 models, 80-180 M/Btu. Coal-Fired Models Oil or Gas Square-Cased Boilers Forced air convertible furnaces for coal, oil, gas, or coal-fired gravity furnaces. Heavy gage, all-steel body; locomotivetype bar grates; waist-high shaker mech anism; pre-formed high-temperature fire brick. 12 models, 20in.-27 in. dia. Round, dry-bottom, fully water legged boilers. Vertical corrugated plate-type flues for large heat transfer area in minimum space. Stainless steel com bustion chamber. SBI rated; built to ASME code. 18 models to 1440 sq ft. Oil or Gas Round-Cased Boilers Gas and Oil Water Heaters GA Boilers are round, dry-bottom, fully water legged. Corrugated plate-type flues. Tankless type coils--210 gal/hr-- standard equipment. Storage tank coils optional. SBI rated; built to ASME code. 12 models to 880 sq ft. Conversion Gas Burners Automatic gas water heaters have spi ral baffled internal flue. Heavy gage "Nor steel" tank. Raised-port cast-iron burner. Oil-fired heaters have vaporiz ing burner. 10-yr., 5-yr., 1-yr. war ranties. 10 gas, 3 oil models; 20-66 gal. Conversion Oil Burners Winter air conditioners with pressure atomizing burner and jet-type combus tion chamber. Tunnel firing design. 12-gage, all-steel heat exchanger. Rapid transfer for exceptional economy. Fac-. tory assembled. 7 models, 80-180 M/Btu. Fully automatic winter air conditioners. Pressure atomizing burner, jet-type com bustion chamber. Corrugated plate-type steel heat exchanger. Tunnel firing. Hydraulically tested. Factory assem bled. 8 models, 60-180 M/Btu. 1134 For boilers, warm air furnaces. Serve 95 per cent of domestic heating needs. Patented, single port, self-piloting, flame retention burner head--with non clogpng features--insures safe, quiet opera tion. 7 models, 50-300 M/Btu. Dependable performance at minimum cost. Spinner for proper mixing of air and atomized oil; choke to govern angle of air mixture with oil spray; motor fan coupling for quiet operation. Easy to install and service. 8 models, 8-6.0 gph. 1135 Air Conditioning Automatic Heating Rheem Manufacturing Company 570 Lexington Avenue, New York 22, N. Y. . Regional Offices: 4361 Firestone Blvd., South Gate, Calif. 1025 Lockwood Drive, Houston 20, Texas 7600 S. Kedzie Ave., Chicago 20, HI. 29-38 41st Ave., Long Island City, N. Y. Sparrows Point 19, Md. Every Rheem Furnace is given a 48point test with pilot and burners ignited. Automatic controls, safety checks, op erations and construction details must be 100 per cent. GAS WARM-AIR HEATING EQUIPMENT RHEEM GAS-FIRED WINTER-AIR CONDITIONER Series 3202--Highboy model, completely automatic, filtered and blower-circulated warmth. Electrically welded firebox is curved to eliminate expansion noises. Oversize blower , is dynamically balanced for quiet, large capacity operation. Shipped completely assembled. Uses any type gas. Avail able with front vent. Easily installed in closet, utility room or basement. Series 3402--Lowboy winter-air conditioner illustrates com pleteness of the Rheem line which embraces a model and size for any home. Vibration-free blower--motor equipped with thermal overload protection, insures true rated capacity. Ex- elusive high-efficiency sloped burner assures quiet extinction. Automatic shut off controls. .. Series 3200--For large homes, stores, restaurants etc. Fully automatic; low-cost operation. Smart, graytone enamel jacket. Fully A.G.A. approved. Specified by the nation's leading architects and builders. RHEEM GAS-FIRED GRAVITY FURNACE Series- 3300--Built for low-cost and economical operation. Electrically welded, air-tight, heating elements; no fumes can get into air stream. Corrugated liner prevents overheating and expansion noises. Large circulation area assures abundant warm-air flow. Automatic temperature controls. Humidifier available. For use mth all gases. RHEEM GAS-FIRED SPACE HEATERS . Series 1600--Rheem has developed these sturdy furnaces with the twin objectives of achieving the greatest possible heat out put from units of the smallest practical size. Nopit is required. Floor and wall furnaces are installed from floor level, thus sav ing costly construction details. . Gas tight, fumeless operation. Contours of die-formed steel heating elements keep warm-air flow at a maximum while baffles inside elements slow the flow of hot gases until all usable heat is transferred to the air. Interlocking safety valve. A.G.A. approved. Series 3909 Series 3409 Lowboy Series 3900 Series 3300 Air Conditioning Automatic Equipment Heating and Cooling REGIONAL OFFICES New York - Atlanta Chicago - Dallas Los 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 building location because the units are quiet and vibrationless. SERVEL 25-TON WATER CHILLER MODEL DUT. An economical source of chilled water for industrial processing and of air conditioning for office build ings, hospitals, factories and defense plants. 25-ton capacity 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 Conditioning equipment under "Incremental As sembly Plan." SERVEL "ALL-YEAR" AIR CONDI TIONER MODEL DE Delivers 5-ton of refrigeration with 96,000 or 144,000 Btu/hr of heating. Operates on existing steam source or comes complete with gas or oil boiler and controls. . SERVEL "SELF-CONTAINED" AIR CONDITIONER MODEL SDE Provides 5-tons of refrigeration. Heating can be added as optional equip ment. Steam from any source supplies the energy for this unit. "CORROSIVE MASTER" EVAPORATIVE WATER COOLERS Available for use with 3 and 5-ton SERVEL units. SERVEL 5-YEAR WARRANTY--All SERVEL absorption equipment carries a 5-year factory warranty. 1137 Air Conditioning gSgiS&F* The Waterman-Waterbury Go. Minneapolis 13, Minnesota ^ . Manufacturers of WATERBURY Coal, Oil and Gas Fired Furnaces and Air Conditioning Equipment WATERBURY COAL-FIRED SEAMLESS FURNACE Gas-tight, welded steel furnace body. A large combustion chamber and radiator with long fire travel insure efficiency and economy. Air Conditioners for homes and larger buildings. Round G a lv . Dia, Round G a lv , ___ H gt. Sue Output BTU Body Body Per Hr. Dia. Hgt. A120 A122 A124 A127 A130 AI33 836R 85,000 94,200 105,100 136,500 180,000 225,000 265,000 20* 52* 41' 22 52 43 24 52 45 27 58 49 30 58 55 33 66 58 36 63 58 Sq. in. Leader Pipe Size Sq. Casing 65' 470 65 524 65 586 72 758 70 1000 80 1230 80 1470 38x38 40x40 42x42 46x46 53x53 55x55 58x58 Size Sq. Casing Outlet 34x34 36x36 38x38 42x42 49x49 51x51 54x54 'SCaqs- ing Hgt. Heating Surface Sq. Ft. 52* 52 52 59 57H 67 67 35.7 39.6 44.3 57.4 76.0 94.0 112.0 Flue Pipe Dia. 8' 8 9 9 9 10 10 Specifications Waterbury Coal-Fired Air Conditioner No. of Filters W idth Casing Length Casing H e ig h t Casing Output Size BTU Per Hr. A120-10 A122-10 A124-12 A127-15 A130-18 A133-22 836R-22 95,400 105.800 118,200 153,000 205,000 250,000 300,000 38' 40 42 46 53 55 58 50* 54 60 62 93 99 102 Size Size Outlet Inlet Opening Opening Size Each Filter CFM Range 52* 52 52 59 57H 67 67 28x34 28x36 34x38 34x42 49x49 51x51 54x54 16x34 20x36 20x38 22x42 36x36 40x40 40x40 2 16x20 600-1400 2 20x25 600-1400 2 20x25 1000-2400 2 20x25 1600-3200 4 16x25 2800-4800 4 20x25 4000-6500 4 20x25 4000-6500 Specifications Waterbury Gas-Fired Gravity Furnace Size 6413A 6415A 6418 Input Rating BTU Per Hr. 80,000 110,000 130,000 Output BTU Per Hr. 60,000 82,500 97,500 Width Casing 28' 30 40 Length Casing 28' 30 37 Height Casing 48' 53 53 Size Outlet Open ing 24x24 26x26 36x33 Flue Pipe Dia, Size Gas Connec tion Required S' a* 6Q 7X Waterbury Gas Conversion Burner A real gas burner, the same as used in the Gas Furnace and Air Conditioner. Muirmim Number BTU Input Cubie Feet of Mixed Gas Cubic Feet of Manuf'd Gaa G-200 200,000 250 360 1138 Air Conditioning The Waterman-Waterbury Co. Minneapolis 13 Minnesota 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 liquidified petroleum gas. W idth 1 Casing Length Casing Height Casing Size Input Rating BTU Per Hr. Output BTU Per Hr. CFM Range Size Outlet Open ing Size Inlet Open ing No. of Fil ters Size Each Filter Size Flue Gas Pipe Connec. Dia. Re quired 6412-7* 60,000 48,000 250 to 550 22* 42* 42* 18x18 18x12 1 16x25 5' 6413A-9* 90,000 72,000 400 to 1000 28 59 48 24x23 24x16 2 16x25 5 6415A-10* 120,000 96,000 600 to 1400 28 61 53 24x23 24x18 2 16x25 6 6418A-12* 150,000 120,000 1000 to 2400 34 71 53 30x30 22x30 2 20x25 7 6420-15 185,000 147,000 1600 to 3200 36 60 S3H 32x32 32x22 2 20x25 8 Also available as a Hi-Boy. W M $ 1 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. Size Input Rating GaLOil Per Hr. Output BTU Per Hr. Size Outlet Open ing Size Inlet Open ing 6313A-9* 6315A-10* 6318-12* 6320-15 .75 1.00 2.35 1.50 84,000 112,000 151.000 168,000 Also available as a Hi-Boy. 28' 59* 48' 28 61 53 34 71 53 36 60 53H 24x23 24x23 30x30 32x32 24x16 24x18 22x30 32x22 W idth Casing f Length I Casing Height Casing No. of Filters a Size Each Filter E 2 16x25 6' 2 16x25 7 2 20x25 7 2 20x25 8 WATERBURY OIL-FIRED AIR CONDITIONER B 300 SERIES Designed especially for large installations, the B 300 OilFired Air Conditioner has a unique furnace body. It features an extra large radiator with a baffle for unusually long fire travel, thus assuring efficient use of the fuel. , Length I Casing Height Cosing [ No. of Filters 1 Size B322-15 B324-18 B327-18 B330-22 B333-25 B336-25 Rating Gal. Oil Per Hr. 2.0 2.5 3.0 3.5 4.0 4.5 Output BTU Per Hr. Width Ii-esa Front Hood 224,000 280.000 336,000 392,000 448,000 504.000 44' 48 52 56 60 66 72* 68 92 100 108 114 Size Size Outlet Inlet Opening Opening Size Flue Each Pipe Filter Dia. CFM Range 55' 40x40 55 44x44 62 48x48 62 52x52 70 56x56 70 62x62 24x28 2 20x25 8' 1600 to 3200 36x36 4 16x25 9 2800 to 4000 36x36 4 16x25 9i 2800 to 4800 40x40 4 20x25 9 4000 to 6500 44x44 4 20x25 10 5000 to 8000 44x44 4 20x25 10 7000 to 10,000 1139 l- . Automatic Heating. Evaporative , v Alt KsOTUiltlOnXTlQ xir Cooling and Blowers Utility Appliance Corporation 4851 S. Alameda St., Los Angeles 58, Calif. Cable address: utilifan, los Annies Utility Gas-Fired Heating Equipment, Evaporative Air Coolers and Blowers Forced Air Furnaces Utility Wall Heaters Floor Furnaces (Vented) Flat and Dual FORCED AIR FURNACES. Compact design permits use in basement or closet . . . dynamically-balanced blower, resilient mount . . . Fiberglass Dustop filters. . . heavy gauge steel, die-formed and welded . . . baked enamel finish. Models: from 70.000 to 200,000 Btu inclusive. FLOOR FURNACES (Vented) FLAT and DUAL. Designed for quiet, efficient, trouble-free, long-life, satisfactory service. "FULL FLOW" performance. High est quality materials. Guaranteed! Four basic models available--45,000 Btu and 60.000 Btu Floor and Dual Register. Controls: (1) Manual, with manual pilot; (2) Manual, with 100 per cent safety pilot; (3) Automatic (self-generating type) with safety pilot. UTILITY WALL HEATERS. All units fit standard 4 in. stud walls without furring and are adjustable for finished wall thicknesses ranging from 4% in.-5}4 in. Single and dual models. Optional Thermostat or 3-rate manual control. Vented. Mod els: from 27,500 to 50,000 Btu inclusive. UNIT HEATERS. Suspended type. Complete unit, burner, heat exchanger, draft diverter motor, fan afid all other parts housed in steel cabinet, baked enamel finish. Adjustable grilles. 65,000-90,000-150,000-225,000-Btu models. EVAPORATIVE AIR COOLERS. Comfort cooling . . . residential, commercial, in dustrial . . . dynamically-balanced . . . centrifugal blower . . . uniform water dis tribution. "No-Sag" aspen-fiber pads. 24 cooling models 800 cfm-13,000 cfm. EVAPORATIVE AIR COOLER PORTABLE ROOM MODEL 1,000 P. For home, office or trailer this portable model with 4-Way directional discharge grill is very popular. Equipped with Direct Drive Blower, Belt Drive Pump and Water Level Indicator. Seal Bonded against rust. . STANDARD BLOWERS. Dynamically-balanced, multiple-vane centrifugal blow ers. Four-side angle iron frame increases rigidity, eliminates vibration . . . permits installation with any of four discharge positions. 9 in. dia.-26 in. dia. . . . Single and Double Width. Guaranteed Air Deliveries. Utility Blowers and Coolers are tested in accordance with the A.S.H.V.E. Code Utility heating appliances are A.G.A. approved. Writs for complete information, catalogs and price. 1140 Air Conditioning . Hteidc`OT Airtherm Manufacturing Company 728 S. Spring Ave. St. Loois 10, Mo. Representatives in Principal Cities For Heating Satisfaction--Think first of AIRTHERM 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 in full range of types and sizes. Write for Catalog 702-A 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-A. AIRTHERM Centrifugal Fan Vertical Horizontal Unit Heaters 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 1208-B. 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 402-A. 1141 Air Conditioning He5ei|ired Campbell Heating Company 3121 Dean, Des Moines 17, Iowa DIRECT FIRED SPACE HEATERS Oil, Gas, Stoker, Hand Fired or Combination Gas and Oil Fired Heater. Guaranteed for 10 Tears from Any Cause, Blower, Motor, Burner and Controls, for One Year Against Defects. The Campbell Direct Fired Space Heaters are designed to be located in the room to be heated but they can be con nected to a duct system for heating any type of building and are quiet enough to be used in churches, schools, etc. They are designed to be shipped as a complete unit ready to connect to fuel line, electric power and flue but they can be shipped in sections for assembling in a basement room. The steel heater is then assembled and welded on the job. Furnished also for Gas, Stoker or Hand Firing Wf Overall Unit Num ber Output Capacity Btu per hr. 65* Return*Air-- No Ducts CFM for 140 Motor Heating Surface SqFt (4) Dimensions Ttwht>a Notlncl. Burner Stack Connection Dia. In. (5) Outlet HP W L Ht. Temp. (3) (2) U8075 725.000 8,850 2-H HP 280 80 80 114 12 U8100 U8125 U8150 U8175 U8200 U8250 893,000 10,900 1,080,000 13,200 1,275,000 15,600 l,440.000i 1.725.000 .1271,,510000 2,160,000 26,400 2-HHP 2-k HP 2-1 HP 2-1 HP 2-1 HP 2-1H HP 320 - 360 . 440 480 600 750 80 80 80 80 93 105 118 130 111280 112200 94 137 136 94 157 136 14 16 16 2108 20 Firing Rates Oil GPH 1,000 Btu GAS C.F.H. 1 1 7.0 8.5 1.192000 18000. 1102..05 1,350 1,600 125 150 14.0 16.5 1,800 2,150 210705 20.5 2,700 250 StLobkse/rH r 56,.000000 118701,,,,000000000000 13,000 (1) Allow 10 to 35 per cent above heat loss for pick up load. If heater is not located in room to be heated an allowance for duct and other radiation losses should be made of 10 to 15 per oent above heat loes figures. (2) Bated air volume produces 75 deg air temperature rise through the heater. This air volume can be varied to suit other conditions. (3) Motor sire can be increased to provide for any duct system. (4) Heat Emission per square foot of heating surface is 3000 Btu per hour or less. (5) An induced draft blower can be furnished if a stack or chimney b not available. The gas passages of the heater axe adequate so that an induced draft blower b not ordinarily necessary. Stack connection can be provided through the top of the to support a stack through the roof, or out the front as illustrated. For data on other Campbell Produete eee page* 112^-1125 DIRECTOR* No. 665 EASTERN SALES: Nsxl Adams, Old Yobs Road, 1142 Lambebtvtlle, N. J. Telephone Air Conditioning E. K. Campbell Company Kansas City 3, Missouri HEAVY DUTY FURNACE FAN EQUIPMENT Standard Units Up To 8,000,000 BTU/HR ; . Made in Units from 500,000 Btu/hr to 8,000,000 Btu/hr. . Available for any fuel or in "All-Fuels" model. Operating efficiencies up to 84 per cent with resultant fuel economy. Counter-Flow heat transfer. ' Drive thru principle exclusively (no suction applications). . Low Internal resistance to flue gases. Fiberglas insulated casing. Baked enamel exterior finish. Extra Heavy welded steel construction throughout. . Available in any required arrangement of duct outlets. . Extreme flexibility of equipment arrangements. . Balanced job'design--blower and furnace sized separately. . Sold only on an engineered basis to fit job requirements. Used in thousands of large buildings over country, the E. K. Campbell Co's Type H-D Furnace-Fan system is particularly suited for buildings containing large spaces, such as industrial plants, churches, schools, hangars, etc. High quality equipment, designed to last, giving unusually low cost on a year service basis. The B. K. Campbell Company guarantees RESULTS as well as its equipment. Inquiries invited regarding LARGE SPACE HEATING PROBLEMS. Manufacturing Engineers since 1910 1143 I Air Conditioning Industrial Heating; Direct-Fired Heaters DRAVO CORPORATION HEATING DEPARTMENT Dravo Bldg., Fifth and Liberty Avenues PITTSBURGH 22, PA. DRAVO Comte^a DIRECT-FIRED HEATERS Gas-Fired Dravo Counterfio Direct-Fired Healer Offer All these Important Advantages: LOW FIRST COST . . . Users report savings of 30 to 60 per cent compared with standard wet-type systems. CONSERVES STEEL ... 50 to 70 per cent less steel required when using direct- fired hot air heating method with Dravo Counierflo Heaters. WORKING-ZONE WARMTH............ Units heat areas of 4,000 to 20,000 sq ft each. Warmth is concentrated in working zone; roof heat loss greatly reduced. NO FUEL WORRIES . . . Burn gas or oil--readily converted from one to other. LOW OPERATING COST . . . 80-85 per cent efficiency at bonnet plus top efficiency in heat distribution holds cost down. AUTOMATICALLY CONTROLLED . . . On-off or modulating controls. The heater looks after itself--no continuous attention required. . EASY INSTALLATION . . . Just hook up fuel, electric and exhaust connections --the heater is ready to go. STAINLESS STEEL CHAMBER . . . Rugged mill-type construction, top-qual ity engineering, assure durability. 5 FUNCTION SERVICE . . . Each unit can provide not only comfort heating, but year-around ventilating, tempered make-up air, process drying, and heat curing. TESTED-APPROVED ... A.G.A. and/or UL seal on all stand ard units. Each heater flame-tested at factory before shipment. CAPACITY AND DIMENSION TABLE . . . Notes: A--CAPACITIES. (/) Gas capacities based cm Nat - - ' ----- ---- ------ ($) Light oil capacities baaed on oil having 140,000 Model Number Btu Output Capacity per hour Approximate Fuel Burned SGA LO HO Cu. Ft. Nat. Gals. Light Gals.Heavy Gas per hr. Oil per hr. Oil per hr. Equivalent Sq. Ft. Steam Radiation Approx. C.F.M. Air at 70T. 40 50 75 100 125 150 175 200 400,000 500,000 750,000 1,000,000 1,250,000 1,500,000 1,750,000 2,000,000 500 625 940 1,250 1,560 1,875 2,190 2,500 3.6 4.5 6.7 8.9 11.1 13.4 15.6 17.8 3.5 4.3 6.5 8.6 10.8 1 3:0 15.0 17.2 1,670 2,080 3,130 4,170 5,210 6,250 7,280 8,330 4,500 5,500 8,500 11,000 14,000 17,000 19,000 22,000 1144 "i ,1 Air Conditioning Industrial Heating; Direct-Fired Heaters DRAVO CORPORATION Atlanta ^Boston Chicago Cleveland Detroit *Nbw York Philadelphia Pittsburgh > Sales Representatives in Principal Cities Manufactured and told in Canada by Marine Industries, Ltd., Sorel, Quebec Export Associates: Lynch, Wilde & Co., Washington 9, D. C. FLEXIBILITY OF APPLICATION Although the Dravo Counterfio Heater attains its greatest space heating efficiency when operating on the floor, it can be suspended horizontally or inverted when floor space is not available. Because of its sturdy construction and the ab sence of fragile refractory, it can be placed in practically any conceivable position. FIVE FUNCTION SERVICE WITH ONE UNIT: COMFORT HEATING--fast, economi cal heating of entire working-zone pro vides ideal comfort conditions. YEAR-ROUND VENTILATION-- maintains positive circulation of clean, fresh air--improves hot weather plant conditions. TEMPERED MAKE-UP AIR--ideal for foundries, paint spray booths and similar applications; replaces contaminated air with fresh tempered make-up air. PROCESS DRYING--process applica tions include dryingof ceramics, paint, hay, rugs, rubber toys, and many other items. HEAT CURING--the efficient design permits use for low temperature curing. Write for bulletin HVG-523-A and specification sheets. Cutaway view of heater Btu/gal and 80 per cent efficcieny.T (S)^Heavy oil capacities based on oil having 145,000 Btu/gal and 80 per cent ef ficiency B--Recommend a minimum height of stack 8 ft above peak of roof. Fan Motor H.P. Approx. Shipping . Weight Width Overall Heater Dimensions Length Height With Nozzles Without Nozzles Stack Diameter l'/i 2 3 5 7 Vi 10 15 20 1,400 1,500 2,500 2,600 3,400 3,600 4.200 /4A00 ' 2*7" 2*7" 3'8" 3'8" 4'3" 4*3" 4'9" 4'9" 4'n" 4'n" 7'3" 7*3" 8'11" 8'11" 9'5" 9'5" 8*1" 8'1" 10'O" 10'O" 11*2" 11'2" 12'9" 12*9" 7'0" 7'0" 8'8" 8'8" 9'8" 9'8" 10*11" 10*11" 8" 8" 10" 10" 12" 12" 12" 12" 1145 Air Conditioning iaSer?*"4 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 niay 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 OUTPUT BTU AIR DEL. CFM 350-A 500-A 750-A 1000-A 1250-A 1500-A 2000-A 350.000 3000-4200 500.000 6000-7800 750.000 8200-4600 1.000.000 12500-15500 1.250.000 15000-17500 1,500.000 17500-21000 2,000.000 21000-24000 L 72 92 100 114 124 128 144 W 36 42 50 54 56 62 66 H 84 90 99 110 1)4 115 125 ARTCRAFT SUSPENDED UNITS I Ratings and Specifications Suspended Units MODEL 75-8 75-SL 100-8 150-3 200-S 250-S 350-8 400-8 500-8 750-8 OUTPUT AIR DEL. BTU CFM-|"S.P. 85.000 85,000 100.000 150.000 200.000 250.000 350.000 400,000 600.000 750.000 800-1000 800-1000 1000-1600 1200-2000 2200-2600 2400-3200 3000-4200 4200-5200 4600-6200 8200-0600 L 63 78 76 79 86 90 104 107 114 146 WH 24 34 22 22 24 34 31 36 31 40 35 42 38 53 40 53 45 62 52 66 1146 Factory Installation Uodd tOQS-M Air Conditioning Automatic Equipment; Direct-Fired Heaters* Unit Heaters Lee Corporation 1001 Tatnall Street, Wilmington, Delaware Manufacturers and Designers of Complete Line of Industrial and Commercial Warm Air Heaters Representatives in all Principal Cities Exclusive Representation to the Railroads: Railroad Supply and Equipment. Inc., First Federal Bide.. Scranton 3, Pa. In Canada: Comstock Lee Heating Division. Canadian' Comstock Company. 206 Laird Drive North. Leaside. Toronto, Canada Lee Heater Number Output Capacity (Btu per hr) Total Heating Surface in sq ft Cu ft of Airper Min. (Approx.)* - Fan Motor HP External Static Pressure (Std.) Maximum External Static Press Available for Duct Work (Larger Motor Required) Temperature Rise (Degree F) Fuel Consumption** A-cu ft Gas per'hr (App.) B-gal Oil per hr (Approx.) Shipping Weight (Approx.) Lbs Refractory Comb. Chamber Stainless Steel Corob. Chamber lee heavy duty heaters LEE HEATERS have beenin 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. 300 400 500 600 750 300.000 400.000 500,000 600.000 750.000 92 106 126 202 235 3500 4500 6000 7000 8500 1 u2 35 u I- V u 1' V r I' 79 380 2.6 3000 2100 82" 500 3.5 3100 2200 77 630 4.3 3300 2400 79 750 5.2 4500 4000 82 940 6.5 4700 4200 Lee Heater Number Output Capacity (Btu per hr) Total Heating Surface in sq ft Cu ft of Air per min. (Approx.)* Fan Motor hp External Static Pressure (Std.) Maximum External Static Press. Available for Duct Work (Larger Motor Required) Temperature Rise (Degree F) Fuel Consumption** A-cu ft Gas per hr. (App.) B-gal Oil per hr. (Approx.) Shipping Weight (Approx.) Lbs Refractory Comb. Chamber Stainless Steel Comb. Chamber 1,000 1,000,000 278 11,500 5 i' 1' 1250 1,250,000 333 14,000 !: 1500 1,500,000 375 17,000 10 1' 1' 1750 1,750,000 423 20,000 15 1' 2000 2,000,000 470 22,000 15 V 80 1250 8.6 6000 5200 83 1560 10.8 6300 5500 82 1880 13.0 7500 6200 . 81* 2190 15.0 8600 7400 84 2500 17.2 9800 8600 * Based on Standard Air at 70 F Free Delivery. . ** Fuel Consumption Based on 1000 Bin per cn ft Gas, 145,000 Btu per Gal Oil, and on 80 per cent Effi ciency for the heater. 1147 Air Conditioning SESS-SK National Heater Company 2182 Cleora Avenue St. Paul 4, Minnesota OIL. GAS and COMBINATION GAS-OIL FIRED UNITS 200,000 to 1,500,000 Btu Air Conditioning Industrial Heating Direct Fired Units National Heater Company 2182 Cleora Avenue St. Paul 4, Minnesota MODEL "H"--Fully self-contained, automatically operated, direct fired unit heaters. Provides working level warm air circulation for factories, foundries, warehouses, garages, hangers and ter minals. MODEL "S"--Similar to Model "D," equipped with side or rear mounted blower cabinets, these styles are par ticularly adapted to modulating type of face and by-pass temperature control systems and where head room is limited. MODEL "D"--Meets specific require ments of large central heating systems necessary in theaters, auditoriums, schools, churches, offices, and super markets. Multiple oversize blowers in sure positive air delivery against resist ance of long supply and return duct runs. Heater Number TD-20 TD-25 TD-30 TD-40 TD-50 TD-70 TD-80 TD-100 TD-125 TD-150 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 CFM at M in. S.P. 2,400 3,200 4,000 5,400 6,600 8,800 10,200 12,500 15,300 19,400 HP Blower Motor X X U 1 m 2 3 5 5 7X Overall Dimensions Width Length 28 28 32 32 32 32 48 48 54 . 54 52 52 60 60 80 80 80 80 100 100 Height 66 66 81 81 81 81 81 81 103 103 1148 Smoke Outlet 10* 10* 10* 10* 12* 12' 12* 12* 14* 14* Shipping Weight 950 1020 1250 1360 1600 1850 2310 2680 3155 3340 HEAVY DUTY "ALL FUELS" HEATERS A durable, welded, one-piece steel con structed heater suitable for coal, oil or gas firing and easily converted from one fuel to another. Designed chiefly for central heating systems, drying, and make up air applications. Large fire box with ample flue travel ensures com plete fuel combustion with minimum stack loss--giving an unusually high efficiency factor whether stoker, oil or gas fired. Provisions made for relief of internal stresses due to repeated expan sion and contraction. Rigid panel type insulated casings are shaped to contour of heaters. Fan capacities listed provide an average 75 deg temperature rise through heater. Blowers or blowerfilter-cabinet units can be sized to meet exact requirements of each installation. PORTABLE HEATING UNIT A "plug in" portable heating system, self-contained and designed for immedi ate heat delivery when and where needed. Shipped fully assembled with induced draft blower and built-in oil storage tank, if desired. Smaller models tare 28 in. and 32 in. wide. Wired and flame tested at factory. 1 Heater No. P-200 P-300A P-300 P-500 P-800 P-1200 P-1800 BTU 200,000 300.000 300,000 500,000 800,000 1,200,000 1,800,000 CFM 3.000 4,200 5,000 7,000 10,500 15,000 23,000 Motor HP 4 i i 2 3 5 7* Ship- 840 950 1400 1600 2060 2900 3800 W idth i 0 o Blow er Heater Number *904 *905 *907 *908 *910 *915 *920 HBtu Output Capacity Sq Ft Heating Surface CFM at in. S.P. 400,000 500,000 700,000 800,000 1,000.000 1,500,000 2,000.000 138 184 234 268 351 519 667 5,400 6,600 8,800 10,000 12,500 18,000 24,000 HP Blower Motor 1 IX 2 3 3 5 7X O'vt w a s 64 70 82 94 118 118 142 imenai S M E'*> 38 69 48 72 48 78 48 78 48 78 66 96 66 96 Smoke Outlet Weight 50 10* 2,370 50 10* 2,640 52 12* 3,020 52 12* 3,280 70 14* 3,730 52 16* 4,880 70 16* 5,920 Air Conditioning Direet-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 Surfaced 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 Fan. 7. Bearings Outside Heater at End of Shaft. - " Four Pass Gas Travel-Counter Current. Engineering Data--Gas, Oil, or Dual Gas-Oil Heaters. Heater Model Number U-300 U-400 U-600 U-600 U-750 IT-1000 U-1250 U-1500 U-1750 U-2000 BTU/HR Output Capacity 300,000 400,000 500.000 600,000 750,000 1,000,000 1,250,000 1,500,000 1,750,000 2,000,000 CFM Blowing Fans A 3,500 4,500 5,500 7,000 8,500 11,000 14,000 17,000 20,000 22,000 3'- \m 3'- 1* 3'- l" 3'- 1* 3'- 8* 3'- 8* 4'- 4' 4 - 4' 4 M0* 4M0* General Dimensions B 2M1* 3'- 7* 4'- 3' 4M1* 5'- 3' 5M1* 7'- 0* 8'- 0' 8'- 0* 9'- 0* C 7M0* 7M0* 7'- 3* V- 3* 8'- 9* 8'- 9* r- 9* 9'- 9* 10'- 9* 10'- 9* Cl r-i* I'-l* l'-3* r-i* im* i#-*' l'-5* l'-S* l'-6* r-6* D r- 6* r-6* r- 7* r- 7* r- 8* 1M1* r-ii* 2'- 0* 2'- 1* r-1* No. of Blow ing Fans 1 1 2 2 2 2 2 2 2 2 Motor HPs Blow ing Fans 1 IK 2 3 3 5 7H 10 15 15 Stack Dia. 8* 8* 8* 8* 8* 10* 10* 12* 12* 12* No. of Nos ale Out lets 2 3 3 4 4 4 4 5 5 5 Write for complete data on stoker fired units and large central systems.. 1150 Air Conditioning Uni* Better, 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. Cutramay view of heater, showing the easti' iron heat exchanger tn place, , Heat exchanger end combustion chamber.% SIZES AND CAPACITIES (also made in five sizes in Blower Type Units)'- Unit No. 215 C 175 C 160 C 140 C HOC 85 C Input B.T.U. Per Hour 215j000 175.W0 160,000 140,oar 110,000 85,000 Output--AGA B.T.U. Per Hour 172,000 140,000 128,000 112,000 88,000 68,000 Sq. Ft. EJ>.R. 744 605 553 484 ' 381 294 1151 Air Del. C.F.M. 3500 2900 2600 2320 1820 1350 Motor H.P. 1 i A 1*0 9*0 Speed R.P.M. 1140 1140 860 860 860 1000 AA ^yrox"^J 525 ? 475 7 450. a 400 M 350 - i 900 ft Ah Conditioning <Jnit Heater* Air Conditioning Unit Heaters and Coolers Fedders-Quigan Corporation 57 Tonawanda Street Buffalo 7, N. Y. Manufacturers of Convector-Radiators, Wall Radiation, Baseboard Radiation, Unit Heaters, Railroad Car Convectors, Unit Coolers, Refrigeration Colls, Air-cooled Fin and Tube Condensers, Clip-on Thermometers, Room Air Conditioners, Automotive Radiators. Car Heater Cores, Electric Water Coolers. i fedders 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. Fa mous lifetime heating element eliminates all danger of fire, shock or burn. Capaci ties from 1500 to 4000 watts--with man ual, wall thermostat or built-in thermo : stat control. All have thermal safety switches. Silver gray enamel finish. A Great Name in Comfort gular louvers in front face of enclosure. Cool air flows down from the wall and is directed out into the warm air stream by means of curved top of enclosure. BIET-IN-WALL BATHROOM Heater Designed to build into the wall, this. 115 volt, 1320 watt heater is designed for small rooms such as baths, bedrooms, kitchens, etc. Employs the famous lifetime heating element that is com pletely safe. Available with or without built-in thermostat. Thermal cut-off prevents overheating. Two-way switch permits ! use of fan without heat. Available in white baked-on enamel or chrome. Right: Fedders Downblow Unit Heater FEDDERS UNIT HEATERS CONVECTOR-RADIATORS For installation in homes, apartments, UNIT HEATERS for Auxiliary Warmth Horizontal Unit Heaters are built in offices, institutions and other locations. capacities from 100 to 1000 EDR and They can be used with steam, and forced I These fan-circulating units are used as auxiliaries to a main Downblow models from 155 to 2050 EDR. or gravity hot water systems. heating system or, where electric rates permit, as main heating Advanced design assures maximum heat In addition to Type F stock models, sources. Require no plumbing or duct work--only circuit wir ing efficiency with minimum use of piping Fedders offers a complete line of Con ing. Employ the completely safe lifetime heating element that and materials. Quick response to manual vector-Radiators for special applica has no exposed hot or glowing wires, gives high thermal con and thermostatic controls contributes to tions. ductivity and resists corrosion. Safety switch prevents over comfort and fuel economy. Circulating Write for catalog giving complete data. heating. Thermostat control available on all models. air in summer season adds to year 'round Suspension Type (left) for wall or ceiling mounting in factories, comfort. Write for catalog. 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-12, Electromode Cor poration. Electromodes are approved by Underwriters' Laboratories and are fully guaranteed. 1152 FEDDERS WALL RADIATION FEDDERS BASEBOARD RADIATION Well adapted for industrial, commer Patent Applied For cial, institutional and household use. Complete \fine for semi-recessed and flush mounted--installations in homes, apartments, offices, hospitals and in stitutions. Anti-streak design adds to cleanliness. Warm air is directed out into the room by Fedders built-in an Cold drawn, seamless steel pressure type tubing is bullet expanded into self spacing, collared, die-formed steel fins. Covers available in expanded mesh or solid front with flat or sloping top with die cut grille. 1153 Air Conditioning YH&SSS? 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 THERMOLIER GRINNELL UNIT HEATERS Thermolier is a quality unit heater. It is backed by Gnnnell's 60 years of varied heating experience. It is so soundly designed and engineered that no changes in its basic construction or op eration have been necessary since its in troduction years ago. Basically, all models incorporate the same quality features. However, the heating element of the Horizontal and Vertical delivery types consist of a single header with a series of copper, pitched, finned U-tubes, while the Textile type utilizes a single header with a series of copper, pitched, webbed U-tubes--par allel to one another. Thermolier motors are not standard stock motors but are built to exact spec ifications for unit heater duty. This assures maximum life at maximum opera ting efficiency with the minimum of electrical input. Fans have aluminum blades with special steel hubs and are made to specifications to insure accurate balance, minimizing noise and vibration. Supply and return pipes.are both on the same side of the unit, assuring com pactness, neatness and economy in installa'tion. Each Thermolier is fur nished with adjustable swivel couplings which provide an easy and practical method of hanging the unit and facilitat ing adjustment after erection. The housing of all units are formed from heavy gage steel and are finished in attractive artmetal slate grey. THERMOLIER CONSTRUCTION FEATURES that save trouble and money Use of a plain thermostatic trap, the simplest and least expensive kind of trap, is practical because of Thermoliers's ex clusive internal cooling leg. Maximum capacity provided at all times and annoying destructive, water hammer eliminated by built-in pitch of tubes and internal cooling leg which as sures continuous drainage of condensate. Damaging strains caused by expansion and contraction eliminated by "U" type expansion tubes. Safety and durability assured with leak-proof tube-to-header construction. Five other important features. Write for Thermolier Catalog. 4 MODELS 18 SIZES Horizontal DeHoerf Textile Model 1154 Velocity Nozzle Vertical Delivery Grinnell Company, Inc. Air Conditioning Unit Heaters and Coolers CAPACITIES--GRINNELL THERMOLIER All based on Standard Basis of Rating (2 lb Steam Pressure and 60 deg Entering 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 . 262 422 352 1062 874 1271 914 1250 852 1433 1127 D66 D71 D91 1140 625 1140 625 1140 625 128.700 90,000 151,700 103,000 196,000 127,500 536 2166 375 1340 632 2716 423 1592 817 2738 532 1551 Dill 1140 640 275,300 195,700 1147 815 5095 3342 Capacity tables for hot water Thermolier on request. exit air temp "F 116 122 133 138 119 123 116 122 129 137 133 138 120 129 116 126 134 147 114 119 conden sation lb per hr air veloc ity at exit--linear ft per min louvers wide open louvers set at 45 velocity nozzle max 37 786 912 1336 31 595 690 1011 50 851 987 1447 40 633 734 1076 64 753 949 1160 56 620 781 955 73 901 1135 1388 58 648 816 998 87 887 1118 1366 65 604 761 030 105 1016 1280 1565 87 799 1007 1230 133 ' 779 93 482 157 977 107 573 203 985 132 558 982 607 1231 722 1241 703 1332 824 1671 980 1684 954 285 1048 1415 1803 203 688 929 1183 Vertical delivery models--for constant speed operation, use bold face figures only --for two speed operation, use both figures model VA1042 VA1045 VA1065 VA1075 VA1101 VA1111 rpm at normal speeds 1725 1250 1725 1250 1140 625 1140 625 1140 600 1140 640 total heat delivered Btu per hr 50.800 40,100 73,600 59,900 109,400 74,500 145.600 94,200 185,000 122,200 257,000 187,000 equivalent direct radiation edr 212 167 307 249 456 310 607 392 770 508 1071 729 cfm at exit air temp 1483 1078 1363 995 2869 1630 2609 1402 4510 2517 4921 3105 exit air temp *F 93 96 114 121 97 105 116 129 100 108 112 121 condensa tion lb per hr 53 41 76 62 113 77 151 98 191 126 266 194 air velocity at exit ft./ twlti 1399 1017 1287 939 1354 769 1231 662 1495 835 1631 1030 Textile models--constant speed operation model rpm at normal speeds total heat delivered Btu per hr equivalent direct radiation edr cfm at exit air temp exit air temp. *F conden sation lb per hr TX70 TX110 1140 1140 69,800 113,700 291 474 2297 2438 Textile Thermolier not available (or hot water systems. 89 106 72 118 air velocity at exit--linear ft per min louvers wide open louvers set at 45 velocity nozzle max 826 1041 1412 877 1105 1500 Grinnell Thermoqers are tested and rated in accordance with rules of the Industrial Unit Healer Association adopted January 1930. 1155 I Air Conditioning tfni* Hmters ILG Electric Ventilating Co. 2880 North Crawford Ave., Chicago 41, HI. Offices In more than 40 Principal Cities i H I! I i i h! i. f till 111:I:t I 1:1 I jj :im0!3i)i!iiisi!i! MlUBBiaiHlIIJli'l' ! 1 1 * I # H IIIIII !| || j| ...................{ Low-Celling Type--for mounting where there is little head-room. Side inlets and outlets assure compact installation. Horizontal Type Unit Heaters--have ILG-buiit 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. Diffusers 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 degrees. Protected against excessive temperature rise by patented auto matic thermal cut-out and magnetic starter. Sizes 5 to 15 KW. Type "HT"--for installations requiring a small volume of heat. Exceptionally efficient. Suitable for constant duty. Non-over heating black heat type coil with individually interchangeable elements. Sizes 1-1/2 to 4 KW. For ILG Propeller and Centrifugal Fans, see page 1244. 1156 AAtirr VU1on-aI.iVtionmg Blower Units. Evaporatbre Condensers, Cooling Towers i nflRD 1819 So. Hanley Rd., St Louis 17, Mo. Manufacturers of HEAT TRANSFER EQUIPMENT Blast Finned Coils--Heating and Cooling Air Conditioning Units--Regular--MultiZone Sprayed Coil Dehumidifiers--Heating & Ventilating Units Evaporative Conden sers and Cooling Towers WATER, STEAM AND DE COILS-- Complete Range of Sizes--9 in. x 12 in. to 36 in. x 120 in. SPRAYED COIL DEHUMIDIFIERS--56 sizes--6 sq ft to 81 sq ft. Air Volumes up to 48,600 cfm. MULTI-ZONE UNITS--(Not Illus trated). Sizes range up to 36 sq ft coil face, and 19,800 cfm. BLOWER UNITS--Ceiling and floor type air-conditioning units. 1 to 50 tons nom inal capacities in 12 sizes. 400 to 20,000 cfm. Various arrangements of dis charge, filter box and motor drive. (Horizontal and Vertical). HEATING AND VENTILATING UNITS --(Not Illustrated). Air volumes from 400 to 21,000 cfm. `EVAPORATIVE CONDENSERS--3 to 75 tons. All refrigerants. All prime surface coils. Indoor or outdoor units. `COOLING TOWERS--3 to 75 tons. Triple tier wetted deck. Indoor or Out door units. Write for catalogs and name of nearest representative * Hot-Dipped Galvanized alter Fabrication 1157 Air Conditioning UannditCHoedaetersrs McQuay, Inc. 1602 Broadway, NJE., Minneapolis 13, Minn. MANUFACTURERS OF AIR CONDITIONING. EQUIPMENT ------Sales Offices in all Principal Cities Air Conditioners PROVEN * Comfort Coolers Air Conditioning Colls Blower Coolers .-Blast Heating Colls (Suspended & Floor Type) Refrigeration Coils Ice Cube Makers (Auto Unit Heaters Unit Coolers Seasonmakers matic) Icy-Flo Accumulators Zeropak Low Temp. Units Cooling Towers PRODUCTS * Evaporative Condensers THE EXCLUSIVE McQUAY NEW RIPPLE FIN COILS Heat transfer surface with higher effici ency and greater durability is assured when you select a McQuay New Ripple Fin Coil. The eiqiansion 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 head ers provide inherent flexibility to ac commodate unequal contraction and ex pansion during operation. Ripple fin coils easily and effectively drain off condensed moisture, with water hang-up being sharply reduced on coils requiring verti cal (up) air flow. _ Ripple fin coils permit increased face velocities without danger of moisture New Ripple-Pin Coil carry-over from the fin surface to the air stream. _ McQuay's numerous header sizes mid 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. MORE THAN 1,000,000 COIL TYPES AND SIZES McQUAY manufactures a complete line of Standard Coils for the Industry. Colls for Heating--1 to 10 rows deep using low or high pressure steam or hot water. Jet-Tnbe (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 Colls for Cooling--1 to 10 rows deep. Direct Expansion Coils for Cooling--1 to 8 rows deep. Refrigeration Colls--all types and sizes. .. Special Coils--of various materials furnished on order for special applications. 1158 McQuay, Inc. Air Conditioning UannditCHoeoaletresrs Horizontal Unit Heater HORIZONTAL UNIT HEATERS Three basic types available--Standard, High cfm, ana Textile. 13 Standard models ranging in size from 21,600 to 360.000 Btu; 11 High efm models 20,300 to 248,000 Btu; 5 Textile models 38,100 to 196,300 Btu. Write for Catalog 321 and 322. DOWN FLOW UNIT HEATERS Down Flow Unit Heater 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) 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. Bloxoer Type Unit Heater Seazonmaker {Ceiling Type) BLOWER TYPE UNIT HEATERS Made in 20 basic sizes covering the entire range from 1000 cfm and 20,600 Btu to 21.000 cfm and 1,600,000 Btu. Filters, face and by-pass dampers, mixing boxes, humidifiers, and all styles of discharge nozzles are available. Write for Cata logs 340 and 342. CENTRAL STATION AIR CONDITIONER (For Large Commercial and Industrial Jobs) . Horizontal and Vertical types. Cools, dehumidifies, filters, and circulates air in summer; heats, humidifies, filters, and cir culates air in winter. Freon and water cooling coils--steam and water heating coils. Cooling capacities from 2 to 70 tons, cfm from 1000 to 15,675 in both sus pended and floor type. Write for Cata log 502. SEASONMAKERS (For Multi-Room Buildings) Room air conditioner, three types: floor, basic, and ceiling. Cooling and heating medium supplied from central plant. Cools, dehumidifies, and filters in sum mer; 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 compactness, attrac tiveness, quiet operation, and ease of in stallation make it ideal for hotels, apart ment buildings, hospitals, etc. Write for Bulletin 700. Air Conditioner (Year-Round) Air Conditioner (Year-Round) Seasonmaker (Floor Type) ICY-FLO ACCUMULATORS The new practical "Storage-Battery" for refrigeration effect is now available for handling heavy loads of short dura tion. Ideal for churches, lodges, mortu aries, noon cafeterias, and many indus trial applications. Write for Bulletin 108. 1159 Accumulator I " Air Conditioning Unit Heaters and Coolera 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 Representatires in 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--16 Models designed ^ for high overhead installation or at low levels. A fully coordinated line of Modine Unit Safety Fan Guard--On all Horizontal Heaters offers greatly expanded oppor- models, a built-in fan guard offers con- tunities for correct unit heater applica- stant protection from exposed fan. tion, Used individually or in combina-Bonderized Casings--All Unit Heater tion, they meet the exacting engineering . , casings are Bonderized to prevent rust demands of any space heating applica- .and bond paint to steel, tion. Efficient Motors--Nationally known Rugged Condenser--Tubes and headers makes of continuous-duty, totally en- are cylindrical and brazed at the joints closed fan type. Rubber mounted to for greater pressure-resisting strength, prevent vibration noise. Individual expansion bends absorb dif- Easy Installation--Direct-from-pipe line ferential stresses. suspension for low cost, fast installation OnerPiece Construction--Tubes, header, of all Horizontal types. Accurately, inlet and outlet connections are brazed rated in strict accordance with the into a rugged, pressure-resisting unit. Standard Test Code for Unit Heaters. NEW MODINE GAS-FIRED UNIT HEATERS New Modine Gas-Fired Unit Heaters in five sizes . . . from 217 to 550 EDR . . . . feature light weight, 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 cleaning. All models are A.G.A. approved for natural, manufactured, mixed, LP and LP-air gases. ' Modine Manufacturing Company Air Conditioning * *<552?* 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-140-47 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. TYPE F--Shown with attractively louvred 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 wall 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. Tape F11 MODINE CABINET UNITS - Modine Cabinet Units were intended for heating with steam or hot water or cooling with chilled water. Water mod els may be used for both heating and cooling. Available in five models from 120 to 640 EDR. Various combinations with and without optional equipment permit free standing, recessed and con cealed installations, wall mounting in upright and inverted positions as well as ceiling mounting. This quiet, high capacity unit for quick, positive distribu tion of heated or cooled air is ideal for offices, lobbies, commercial and public buildings. Important new design and perform ance improvements make it possible to closely match the specific requirements of the application. Casings fully coordinated in over-all size, size of flanged edges and diameters and location of mounting holes, simplify installation in a single duct. Smaller duct connections are possible because all surface within casings is heat transfer surface. MODINE HEATING COILS The extensive line of Modine Heating Coils is engineered to meet the diversified requirements of modern air-handling systems. In addition to more than 1200 catalogued heating coils for use with steam and hot water, Modine produces many custom built coils for installation in air-handling equipment produced by other firms. Types include standard and non-freeze heating and booster coils, and hot water heating coils. 1161 Air Conditioning aUnnditCHoeoaletersrs McCord Corporation AIR CONDITIONING AND REFRIGERATION DIVISION Detroit 11, Michigan ' FACTORIES: DETROIT, MICH., WASHINGTON, IND., WINDSOR, CANADA MANUFACTURERS OF UNIT HEATERS, CONDENSERS FOR DOMESTIC AND COMMERCIAL REFRIGERATORS MCCORD HORIZONTAL TYPE UNIT HEATERS 16 models for industrial, commercial general office, and store use--a type size and design for every application. Features: modern design, high capacity. Air Conditioning Unit Heatsis and Coolers 8U. . PAT. OFF. J. Murray Manufacturing Co. Wausau, Wisconsin Offices In Principal Cities MANUFACTURERS OF GRID UNIT HEATERS AND GRID BLAST COILS Designed and testedto operate with steam or hot water systems--for steam pres sures from 2 lbs to 250 lbs. Engineered along the same lines as the standard GRID Unit which had aluminum heating sections and has been on the market since 1929. MCCORD VERTICAL TYPE UNIT HEATERS 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-resrticting. 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 con 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. 1162 One piece construction "fin" heating sections of high test cast iron--no sol dered, brazed, welded or expanded con nections. Patented. Overall dimeneione for netoUatian of Cart Iron GRID Unit Heater Cl (CAST IRON) SERIES GRID UNIT HEATER DATA No. Capacities Dimensions Motor 5 P8I Steam Vol. 60F Air Pipe Sise Sup* Approx. port Ship. A B C D E Fan CFM HP RPM Btu/ Hr Final Temp. Supply Return F Rod Dia. Weight Lbs. ci-iooo lit 13* 12* 9* 15* 1/25 1550 572 29,080 106 i* u M 150 Cl-1200 14* 16* 12* 12* m 1/15 1650 798 45,450 112 i* 1* H 210 CI-1500 17* 15* m 16 231 1/8 1750 1500 76,500 107 1* M 280 CI-1520 17* 15* 11* 21 28| 1/8 1760 1700 101,500 114 i* 1* H 890 CI-2000 22* 20* Hi 21A 28* 1/0 1150 2600 143,000 CI-2026 22* 20* 11* 25* 35* 1/6 1150 2876 173,640 no 115 2 2 1* M 490 1* H 520 CI-2600 27* 25* 18 25* 351 1/2 1150 4850 224.000 107 2 1* H 700 CI-2504 27* 25* 13 25* 35* 1/4 1150 8300 206,000 117 2 1* H 660 Cl-2680 27* 25* IS 31 "40* 1/2 1160 4650 276.800 114 2 1* H 900 Cl-8000 82| 81 13 31 40* 1/2 850 6800 382,000 108 2* I* H 1020 ci-tooo S2| 81 13 81 40* 1* 1150 8000 880.000 108 2* 1* H 1070 NO ELECTROLYSIS TO CAUSE CORROSION Low maintenance expense. More air changes per hour. Positive "directed" heat. No leaks--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. 1163 Air Conditioning Unit Beaters and Coolers a&l HERmnn nELson Division of the American Air Filter Company, Inc. Louisville, Kentucky Moline, Illinois Branch Offices and ProductApplication Engineers in the Following Cities: Atlanta, Ga. Baltimore, Md. Boston, Mass. Buffalo, N. Y. Cape Elizabeth,Me. Chicago, III. Cincinnati, O. Cleveland, O. Columbus, O. Dallas, Tex. Denver, Colo. Des Moines, Iowa Detroit, Mich. Duluth, Minn. Grand Rapids, Mich. Greensboro, N. C. Houston, Tex. Indianapolis, Ind. Jackson, Miss. Kansas City, Mo. Los Angeles, Calif. Louisville, Ky. Memphis. Tenn. Miami, Fla. Milwaukee, Wis. Minneapolis, Minn. Missoula. Mont. Moline, III. Nashville, Tenn. New Orleans, La. New York. N. Y. Oklahoma City, Okla. Omaha, Neb. Philadelphia, Pa. Phoenix, Abiz. Pittsburgh, Pa. Portland, Ore. Richmond, Va. Saginaw, Mich. St. Louis, Mo. Salt Lake Citt. Utah San Antonio, Tex. San Francisco, Calif. Seattle, Wash. Spokane, Wash. Springfield, Mass. Syracuse, N. Y. Washington, D. C. HERMAN NELSON HORIZONTAL SHAFT PROPELLERFAN TYPE UNIT HEATERS. Designed for ceiling suspension, these unit heaters project warm air downward in an angular direction. Copper heating element for use with steam or hot water, incorporates patented stay tube which maintains proper relationship between headers without increasing strain on loops thus prolonging life of unit. A wide variety of models, sizes and arrangements. HERMAN NELSON VERTICAL SHAFT PROPELLER-FAN TYPE UNIT HEATERS. For high ceiling installations. Dis charge air vertically downward, or at an angle to vertical in various directions. Long life copper heating element for use with steam or hot water incorporates patented stay tube. Units available with either high or low velocity discharge, each with a wide range of capacities. HERMAN NELSON DE LUXE UNIT HEATERS. Efficient economical, compact, quiet and attractive, these Unit Heaters provide the ideal method for heating offices, showrooms, corridors, markets, stores, etc. Copper heating element in corporates patented stay tube. Units may be placed on floor, wall or suspended from ceiling. Eighteen models, sizes and arrangements. HERMAN NELSON CENTRIFUGAL-FAN TYPE UNIT HEATERS. The Herman Nelson Centrifugal-Fan Type Unit Heater can be applied to solve a multitude of heatmg and ventilating problems. With 1,890 combinations of models, sizes and speeds available, there is a unit to fit the average requirements of commercial and industrial buildings of all types. HERMAN NELSON DRAFT/STOP UNIT VENTILATORS . . .The DRAFT/STOP Unit Ventilation System developed by Herman Nelson employs a new design principle. Drafts are trapped before they can reach classroom occupants. Cold drafts are prevented from circulating throughout the room to create constantly changing temperature levels. DRAFT/STOPproduces abundant fresh air of even temperature ... a truly healthful atmosphere that minimizes the possibility of health hazards. The system is quiet, has a smart modern appearance and is economical, being almost en tirely free of maintenance problems. 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 THE AMERICAN SOCIETY OF HEATING AND VENTILATING ENGINEERS. 1164 Air Conditioning HERmnn nEison Division of the American Air Filter Company, Inc. Louisville, Ky. Moline, HI. ml bSJwot HERMAN NELSON DIRECT DRIVE PROPELLER FANS. Provide most economical form of quality ventilation obtain able for industrial buildings of all types. 7 standard sizes available with wheel diameters from 14 to 36 in. and capacities from 655 to 12,400 cfm. There are 7 high powered models to operate against static resistance of % in., with wheel diam eters from 14 to 36 in. and capacities from 1,200 to 14,600 cfm. Also three models especially adapted to small store and office applications. Standard Models available with two speed motors. HERMAN NELSON BELT DRIVE PROPELLER FANS. For public and commercial building installations where slow speed, quiet operation are required. Twelve sizes of the stand ard model with wheel diameters from 24 in. to 54 in. Also six sizes of the High Powered model with the same wheel diam eters. Capacities: 5,650 to 36,150 cfm. Due to quiet operation of Herman Nelson Belt Drive Propeller Fans, use of two speed motor is unnecessary. HERMAN NELSON DIRECT DRIVE UNIT BLOWERS. De signed for many applications, such as fume hoods, toilet ventilation, chemical laboratories, industrial processing and drying problems. Compact, direct connected, motor driven units have universal discharge and mount on floor, wall or ceiling. Available in four sizes with 9 speed combinations. Wheel diameters from 6})j in. to 11 in. and capacities from 360 to 2,265 cfm. HERMAN NELSON BELT DRIVE UNIT BLOWERS. Fully self-contained unit including motor, drives and housing; slow speed or non-over-loading type wheels available; adjustable motor pedestal with vibration dampers; universal discharge; nine sizes with 70 drive combinations. Available with any rotation and discharge. Wheel diameters from 11 in. to 30 in. and capacities from 980 to 16,892 cfm. HERMAN NELSON CENTRIFUGAL FANS. Herman Nelson Centrifugal Fans are designed and constructed for smooth, efficient, long-life operation on any system requiring the use of a Class I or II centrifugal fan. These fans are available in either slow speed or non-over-loading type; 17 wheel diameters from 12to 73 in.; single or double width; 8 arrangements for direct or belt drive; and any rotation or discharge. 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 THE AMERICAN SOCIETY OF HEATING AND VENTI LATING ENGINEERS. 1165 Air Conditioning 2a JOHN J. NESBITT, INC. Philadelphia 36, Pa. ' Manufacturers of THE NESBITT SYNCRETIZER Heating and Ventilating Unit, and NESBITT WIND-O-LINE RADIATION, and THE NESBITT PACKAGE, sold by Nesbitt and American Blower Corporation; NESBITT SERIES D HEATING SURFACE with Steam-distributing Tubes, NESBITT SERIES H HEATING SURFACE, and NESBITT SERIES W COOLING SURFACE, sold by John J. Nesbitt, Inc.; NESBITT CONVECTORS, sold by plumbing and heating wholesalers WEBSTER-NESBITT UNIT HEATERS (See page 1441), distributed in U.S.A. by Warren Webster & Company NESBITT SYNCRETIZER--Series 500 NESBITT SURFACE For heating and ventilating school rooms, offices, etc. where the continuous introduction of outdoor air is desired. Incorporates exclusive Nesbitt features: Comfort Control automatically regulates temperature of air stream's protective blanket; Air Volume Stabilizer prevents more than designed percentage of out door air from entering the unit, saves fuel; Uniform Air Discharge Tempera tures assured by Nesbitt Dual Steamdistributing Tube radiator; DirectedFlow Adjustable Outlet permits air discharge pattern best suited to indi vidual classrooms. For data on Syn cretizer and schoolroom ensemble con sisting of the Syncretizer, Convector, and storage units, Pub. 261. Wind-O-Line Radiation New auxiliary heating for down-draft protection under long window exposures. Available wall-hung in attractive casing for use with free-standing Nesbitt Syn cretizer, or recessed in component units of The Nesbitt Package. Publication 264. Engineering Pub. 261, Section W. Nesbitt Series B Thermovent For heating and ventilating audito riums, gymnasiums, assembly halls, and similar gathering places. Pub. 227. SERIES W. Continuous or cleanable tube water surface for air-cooling, de- humidifying or heating. Copper tubes, aluminum fins. Wide range of sizes in three types: Type WD with exclusive freeze-jrroof 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. 255. 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 steam- distributing 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 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. 282. 1166 Air Conditioning ""d cSte? Refrigeration Economics Co., Inc. 1231 Tuscarawas St. E., Canton 2, Ohio RECOY PRODUCTS C. T. Coils Ceiling Diffusers C. F. Coils C. T. Colls--Continuous-tube down-draft fin-coils are still first choice for meat coolers, or other products requiring; high humidity and gentle air circulation. Ceiling Diffuser--Ceiling diffusers distribute the cooled air across the ceiling, so the draft does not strike the products stored or occupants. C. F. Coils--Continuous fin coils for unit coolers, blast heaters, air conditioning and condensers. Shell Condenser Evaporative Condensers Floor Units Air Conditioning--Air Conditioning units of ceiling or floor type in all capacities, for cooling, heating, or both. Shell Condenser--Shell and tube, also shell and fin coil condensers. Evaporative Condensers--Evaporative condensers from 2 to 100 tons. Brine spray cooling to 25 tons. Floor Units--Floor units with cooling surface exposed to view have a definite ad vantage over those with coils hidden. Water Cooling--Self contained complete ice water and brine coolers complete with high and low sides, circulating pumps, controls, and insulation. 1} to 50 hp. Wall Units--Recoy "All Seasons" wall units provide a damper for deflecting the cold air down along the wall or out horizontally into the room, thus providing proper air circulation for "All Seasons." Automatic Defrost Units--Complete, ready for electric, liquid, suction, and hot gas connections. One coil working always, both 98 per cent of time. 1167 . Air Conditioning Unit Heaters and Coolers The TRRV1E Company 2021 Cameron Avenue, La Crosse, Wisconsin In Canada: Trane Company of Canada, Ltd., Toronto, Ontario--Offices in 14 Canadian Cities COMPLETE LINE HEATING AND CONDITIONING Over 80 Trane Sales Offices in U. S. Albant, N. Y. Aij*entown, Pa. Amarillo, Texas Appleton, Wis. Atlanta, Ga. Aurora, III. Baltimore, Md. Batport, L. I., N. Y. Billings, Mont. Birmingham, Ala. Boston, Mass. Buffalo, N. Y. Canton, Ohio Charleston, W. Va. Chattanooga, Tenn. Chicago, III. Cincinnati. Ohio Clarksburg, W. Va. Cleveland, Ohio Columbia, S. C. Columbub, Ohio Dallas, Texas Davenport, Iowa Dayton, Ohio Denver, Colo. Des Moines, Iowa Detroit, Mich. Duluth, Minn. Erie, Pa. Flint, Mich. Gainesville, Fla. Grand Rapids, Mich. Greensboro, N. C. Greenville, S. C. Harrisburg, Pa. Houston, Texas Indianapolis, Ind. Johnson Citt, Tenn. Kansas City, Kans. Knoxville, Tenn. La Crosse, Wis. Lansing, Mich. . Lake Charles, La. Los Angeles, Calif. Louisville, Kt. Memphis, Tenn. Miami, Fla. Milwaukee, Wis. Nashville, Tenn. Newark, N. J. New Orleans, La. New York, N. Y. N obth Tarryton.N.Y. Oklahoma City, Okla. Omaha, Nebr. Philadelphia, Pa. Phoenix, Aris. Pittsburgh, Pa. Portland, Maine Portland, Orb. Providence, R. I. 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 LIRE. The Trane Company fabricates a complete line of heating, cooling, air conditioning and air handling equipment. So comprehensive is the Trane Line that any number of complete heating and air conditioning systems can be de signed in which all the major parts are made by Trane. TRANE CONVECTORS--Attractive, ef ficient, easy-to-install units. Available for either steam or hot water heating systems in a variety of cabinet types. ` TRANE COILS--There are Trane Ex tended Surface Coils for every heating or cooling application. Types include coils for steam, not water or booster heating, direct expansion or water cooling. Type E Heating Coil TRANE PROJECTION UNIT HEATERS --A Trane development, the Model P taps the reservoir of wasted ceiling heat, offers ideal solution to multitude of heating problems. Illustrated here with the new adjustable Louver Cone Diffuser for uniform heat distribution. TRANE HORIZONTAL UNIT HEAT ERS--Combines the Trane broad blade propeller fan, extended surface coil and many other features into a heater that is rugged, efficient and handsome. Avail able in 24 sizes 22,000 to 352,000 Btu. New Louver Fin Diffuser completely controls direction of air flow. . TRANE BLOWER TYPE UNIT HEAT ERS--Better known as Torridors they combine Trane Centrifugal Fans, Ex tended Surface Coils, rugged casings to provide the ideal unit for heating large spaces and for process applications. TRANE GAS UNIT HEATERS--The built-like-a-boiler unit that's available in seven sizes. These new units are suitable for every heating application. Capacities from 50,000 to 210,000 Btu. Force-Flo Heater Wall-Fin Heater 1168 The Trane Company Air Conditioning Unit Heaters and Coolers TRANE FORCE-FLO HEATERS--A de luxe unit heater with centrifugal fan. A powerhouse of heat in a neat appearing cabinet. Capacities from 17,700 to 105,000 Btu. TRANE WALL-FIN HEATERS--Finned radiation in both ferrous and nonferrous construction. For industrial and com mercial applications. Lengths 2 ft to 12 ft in 6 in. increments. Expanded metal grilles and cabinets available. TRANE UNIT VENTILATORS--Meets every requirement of ventilation in School rooms and similar installations. : Units available with matching shelving and auxiliary convectors. TRANE ROOF VENTILATORS--A com plete line of powered ventilators for supply and exhaust and vertical units for exhaust only. Capacities from 355 to 25,000 cfm. TRANE STEAM SPECIALTIES--Over 150 items including three types of valves, thermostatic traps, inverted bucket traps, float traps, strainers, vents and direct traps. '" *; TRANE HOT WATER HEATING SPE CIALTIES--Included are the Trane Circulator, FloValves and Fittings. Combined with Trane Convectors they provide an ideal warm water heating system. TRANE MULTI-ROOM AIR CONDI TIONING SYSTEMS--Includes Cus tom-Air which provides separate con trol of temperature ana moisture, UniTrane for control of temperature and moisture without the use of ducts. TRANE CLIMATE CHANGERS--A unit type air conditioner, designed for year- round air conditioning. Available in various coil combinations with or with out humidification equipment. Capaci ties from 450 to 23,000 cfm. TRANE SELF-CONTAINED AIR CON DITIONERS--Packaged units, ideal for office, shop or home air conditioning. Centrifugal Fan TRANE EVAPORATIVE CONDEN SERS--For condensing Freon and Methyl Chloride refrigerants. Uses mini mum amount of water. Capacities from 3 to 100 tons. TRANE REFRIGERATION EQUIPMENT--The CenTraVac is a hermetic centrifu gal refrigeration unit in sizes from 50 tons up. Trane Reciprocating Compressors and Condensing Units are available from 3 to 50 tons. TRANE FANS--Centrifugal in Class I and II. Backwardly inclined or forward curved types, all arrangements. Wheels from 12 in. to 108 in. Capacities from 668 to 491,000 cfm. Utility ana Propeller Fans with direct or belt drive. TRANE EDUCATIONAL MATERIAL--The Trane Air Conditioning Manual ($5.00), unbiased textbook for the engineering profession. The Trane Refrigeration Manual ($1.50), a reference for servicing and installing all types of refrigeration systems. OTHER TRANE EQUIPMENT--1. Condensation and Centrifugal Pumps; 2. Dry Type Water Chillers; 3. Product Coolers; 4. Fluid Coolers; 5. Brazed Aluminum Heat Transfer Units; 6. Transportation Air Conditioning Equipment; 7. Shelland-Tube Heat Exchangers; 8. Evaporative Coolers; 9. Air Washers; 10. Multi Zone Air Conditioners. 1169 Air Conditioning Unit Heaters Office and Factory LINDEN, N. J. L. J. Wing Mfg.Co. 59 Vreeland Mills Road, Linden, NT J. Canadian Factory: MONTREAL Branch Offices in European Representative for Heaters: Principal Cities Wanson, Haren-Nord, Brussels, Belguim WING REVOLVING UNIT HEATERS Wing Revolving Unit Heaters draw the air from the roof or ceiling, pass it through the Wing Featherfin Heating Section, and project the resultant heated air through slowly revolving discharge outlets to the working level below. As the moving warm air reaches the working level, it mixes uniformly with the cold air, circulates around bulky machinery or other obstacles and penetrates into cold damp corners, repair pits, etc. jHxhm-ae OviUi Thus is assured a comfortable, uniform temperature throughout the entire plant, a condition not attainable with the single-direction discharge of the ordinary unit heater. The effect on the worker, because of the gentle air motion, is a pleasing sensation of fresh, live, invigorating warmth. The Wing Revolving Unit Heater is available in three different types of revolving discharge outlets, as illustrated above, to suit the varying requirements of buildings and rooms of different heights and shapes. An additional feature of the Wing Re volving Unit Heater is its use for summer cooling. With the steam turned off and the fans on, the revolving discharge outlets provide an equally pleasant cooling effect. Wing Revolving Unit Heaters are also available in Gas-Fired models. Bulletin BR-e. 1170 L. J. Wing Mfg. Co. Air Conditioning Unit Heaters Design No. 1 Design No. 7 Design No. i-HV Design No. 8 Design No. 3 Design No. 4 WING Design No. 8 FIXED DISCHARGE UNIT HEATERS Eight different designs of outlets meet the requirements of every type, size and height of building or occupancy. Located near ceiling or roof, the accumu lation of hot air in the upper spaces, with the accompanying costly waste of heat, is prevented. Bulletin HRJS. uwn. ntaijiKt), liAKAUK HEATERS Applicable for heating the inrush of cold air at large door ways and for garage heating. Often cuts heating costs in half. Bulletin HR-6. FOR LOW CEILINGS Position of fan and motor are reversed to meet conditions Type **LC'* of ceiling or roof height, form and shape of building, coverage etc. Bulletin HRJi. . ' WING UTILITY UNIT HEATERS A lightweight suspended unit heater for delivering heated air in one general direction. Has the same powerful fan and rugged heating element as WING Featherweight Unit Heaters. Bulletin U-9. WING GAS FIRED UNIT HEATERS For natural or manufactured gas. Combines gas burners, heat exchanger and combustion chamber with motor driven Wing fan and discharge outlets. The revolving discharge outlet distributes the heat continuously in constantly changing directions. Bulletin OH-1. FEATHERFIN HEATER SECTIONS For heating or cooling air for any purpose by steam, hot or cold water or refrigerant. The heating element is extremely light and, for equal heat transfer, offers little resistance to air flow. Available for any desired final air temperature. Bulletin HS-8. VARIABLE TEMPERATURE SECTIONS Invaluable in supplying fresh air of varying temperatures for space heating or process work. Close control of the de livered air temperature. Positively will not freeze. Manual or automatic control. Bulletin HS-8. WING INDUSTRIAL FOG ELIMINATORS Eliminate fog, odor and fumes in dyeing, bleaching and finishing plants, creameries, pasteurizing, bottling, canning and packing plants, chemical works, paper mills, steel pickling plants, etc. No ducts are required. Bulletin FE-18. 1171 L. J. Wing Mfg. Co. Air Conditioning FSiSd mowers WINGFOIL DUCT FANS A compact, economical "housed fan" designed to operate against static pres sure. Available in either the elbow or straight-line type. The motor is en tirely outside the housing--always cool, clean and easily accessible--and out of the path of hot or dirty air or gases which might be injurious to it. Delivers large air volumes with low lower consumption efficiently against static-pressure, itraight line type furnished for horizontal or vertical operation and is driven by V-belt. Elbow type may have either belt or direct drive. Complete range of sizes from 200 to 85,000 cfm. Bulletin F-ll. WING MOTOR-DRIVEN BLOWERS (1) Simple and Rugged Construction (2) Compact Design (3) Low Installa tion Cost (4) High Efficiency, Quiet Performance (5) Built-in Voltrol Vanes (capacity regulating dampers) actuated by an external balanced lever. Can be adjusted manually or connected to any standard combustion control regulation. Precise in construction. Reduction in volume is accompanied by a reduction in horsepower over a wide range. SW-51. WING TURBINE-DRIVEN BLOWERS Applied to hand, stoker, oil or pulverized fuel fired boilers, increase boiler capacity, maintain constant steam pressure and permit complete combustion of low-cost fuels. The exhaust steam, free from oil, can be used for heating or proc esses. Bulletin SW-51. WING DRAFT INDUCERS Provides positive, uniform draft re gardless of weather conditions and as sures thorough and efficient combustion with high. COi content. Eliminates high, costly, unsightly stacks. Bulle tin 1-51. WING SYSTEM OF CONTROLLED COMBUSTION For low pressure heating boilers and small power boilers. Increases capacity and permits use of lowest cost fuel. Eliminates necessity of frequent firing, allowing intervals as great as 24 hours even in zero weather. " " '* " ,nn WINGFOIL SAFETY VENTILATING FANS An axial flow fan that will deliver air against static pressure, quietly and efficiently. Capacities to 100,000 cfm. Bulletin F-ll. 1172 Air-Conditioning Young Radiator Co. Dept. 541, Racine, Wis. Sales and Engineering Offices in Principal Cities ' HEAT TRANSFER - PRODUCTS 'IjgPp Heat Transfer Products for Automotive and Industrial Applications. Heating, Cooling, Air Conditioning Products for Home and Industry. HEATING,' COOLING & AIR CONDITIONING EQUIPMENT Left: Type "SH" unit heaters for hori zontal air discharge. Capacities from 19,000 to 325,000 Btu per hour. Right: Convector-Radiators in Standard ized Types--circulate rather than radi ate heat. Used with steam or hot water systems. Cabinets blend with architec ture and room decor. Left: Type "V" or Vertiflow unit heaters for vertical air discharge. Capacities from 52,600 to 552,000 Btu per hour. Left: Cabinet Type unit heaters offer unit heater performance plus the beauty of modern cabinet styling. Capacities from 26,200 Btu to 115,000 Btu per hour. Right: Type "BH" blower unit heaters for floor, wall or ceiling mounting. Ca pacities from 109,400 to 1,047,000 Btu per hour. Young "YAC" Air Conditioning Units provide year around air conditioning. Available in eight sizes, in capacities ranging from 450 cfm to 15,750 cfm, horizontal (left) or vertical (right) units. Heating coils furnished for either steam or hot water; cooling coils for water or direct expansion operation. Possible to provide a unit for heating only, cooling only, or for heating and cooling. Com pact, easy to handle, and install. HEATING & COOLING COILS Left: Type "W" water coils for cooling or heating with either unit or central plant systems. Five widths, 11 to 35 in.; 2 to 8 rows of tubes; many lengths. Right: Types "B" and "A" blast coils for either unit or central plant heating and air conditioning systems. Steam distributing tube type available. Other types in Young's complete line of coils include: Type "E," evaporator coils for direct expansion cooling sys tems; Type "C," unencased coils for use in factory built unit air conditioners available in either standard or steam distributing tube types. 1173 Air Conditioning and Heating Piping Copper and Brass The American Brass Company General Offices: Waterbury 20, Conn. District Offices in Principal Cities Anac^idA from nync^t^con^mncr IN CANADA: Anaconda Ambbican Buass Limited, New Toronto, Ontario PRODUCTS--Anaconda Deoxidized 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 stalled in restricted space where the use of a wrench would be impossible. For Heating, Plumbing and Air Conditioning Anaconda Types K and L Deoxidized 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: 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. 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, Accuracy of Dimensions--Anaconda Copper Water Tubes are all finished to the close size. tolerances required by the ASTM and Federal Specifications, which have been found essential for effi cient assembly with solder fittings. the long radius turns of elbows and the smooth inside surface of wrought copper fittings further reduce friction losses. REFRIGERATION TUBING Anaconda Dehydrated Copper Refrig These factors naturally increase the efficiency of the system, particularly when it includes a forced pressure circulator. eration Tubes are manufactured in accor dance with ASTM Specification. B68, in all standard sizes up to and including % in. O.D., in 50-foot coils. Longer lengths are made to special order. These tubes are manufactured under excep 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 tionally clean mill conditions and close technical control to assure clean, smooth inside surfaces, unusual accuracy in size and shape, and uniform softness. The tubes are sealed immediately after an nealing and dehydrating. . 1174 Air Conditioning and Heating Piping cop*r nd Br> The American Brass Company VIBRATION ELIMINATORS American Vibration Eliminators--Com pressor vibration and noise are muffled in a line equipped with an American . Vibration Eliminator. What's more, the line that absorbs vibration is far less apt to fail from fatigue. An American Vibration Eliminator is a deluxe prod uct. The corrugated bronze tubing is seamless. Copper ferrules and tube ends are bronze welded. Each unit is pressuretested under water, is spotlessly clean and dry, with ends firmly sealed. ANACONDA "85" RED BRASS PIPE 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. 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. EVERDUR* Everdur Metal is the original coppersilicon alloy group. It is manufactured by The American Brass Company in five standard compositions and in practically all commercial forms. This high strength engineering metal is resistant to a wide range of corroding agents. Because of a versatile combina tion of useful properties, Everdur has become standard as a materal for equip ment in many fields of engineering and industry. In addition to their non-rusting prop erties and high strength, Everdur alloys possess many qualities not usually found in metals of this character. They are unusually resistant to general atmo spheric conditions and other normally corrosive factors. Everdur alloys have excellent machining and working charac teristics and can be fabricated into a variety of forms and shapes. Everdur alloys areavailable for oxy-acetylene,car bon and inert-gas-shielded arc welding. Everdur Tanks--Everdur copper-sili con alloy is an ideal material for durable, rustless water tanks of every descrip tion--from domestic range boilers to large storage heaters for hotels, laun dries, hospitals, textile plants, schools or breweries. Everdur is made in all commercial shapes including annealed tank plates which have physical properties as given in AJS.T.M. Specification B96. 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. Welds made with annealed Everdur tank plates meet the requirements for U68 and U69 construction in the AJ5.M.E. Code for Unfired Pressure Vessels. For additional data and names of fabri cators address our nearest District Office. EVERDUR FOR AIR CONDITIONING 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 Americas Brass Company registered at the U. B. Patent Office. RESTRICTOR TUBE FORMED TUBE PARTS HARD COPPER TUBE CUT TO LENGTH COPPER WATER TUBE IN COILS AND STRAIGHT LENGTHS FITTINGS FOR TYPES K AND L TUBES VIBRATION ELIMINATORS CHARGING HOSE FLEXIBLE REFRIGERATION TUBING CONDUIT DIE PRESSED FORGINGS COPPER, BRASS, BRONZE IN SHEETS, WIRE, RODS, TUBES AND SPECIAL SHAPES 1175 Air Conditioning and Heating Piping ndw Tubm* Chicago Metal Hose Division Flexonics Corporation Maywood, niinois ' District Offices Atlanta Boston Cincinnati Cleveland Detroit Ft* Worth __ ' Los Angeles New York Philadelphia St. Louis San Francisco Distributing Outlets in Principal Cities In Canada: Flexonics Corporation of Canada* Ltd** Brampton, Ontario REX Super Service Vibra-Sorbers Rex Vibra-Sorbers control vibration and reduce noise in refrigeration and air con ditioning machinery. All-metal con struction 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: -fa in. to 4 in. inside diameters. BURST PRESSURES: 1,000 to3,700 psi. LENGTHS: Standard stock lengths. Special lengths available on order. COUPLINGS: Stock units with-male or female sweat fittings; also available with male pipe thread fittings. 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 ts 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 >ni to 12 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. 1176 ,. _ .... . , rr . Pipe and Tube Air Conditioning and Heating Piping of copper and Copper Alloys Revere Copper and Brass Incorporated Executive office: 230 Park Avenue, New York 17, N. Y. MILLS--Baltimore, Md.; Chicago* III.; Clinton* III.; Detroit, Mich.; ' Los Angeles and Riverside, Calif.; New Bedford* Mass.; Rome* N. Y. DISTRICT SALKS OFFICES--Atlanta ,Ga.; Boston* Mass.;Buffalo, N, Y.; Cincinnati* Ohio;Cleveland*Ohio; Dallas*Tex.;Datton*Ohio; Grand Rapids* Mich.; Hartford* Conn.; Houston, Tex.; Indianapolis, Ind.; Milwaukee, Wib.; Minneapolis* Minn.; New Yorx, N. Y.; Philadelphia, Pa.; Pittsburgh, Pa.; Providence, R.I.; St. Louis, Mo.; San Francisco, Calif.; Seattle* Wash. REVERE PIPE AND TUBE OF COPPER AND COPPER ALLOYS For Heating, Air Conditioning, Plumbing, Revere Copper Water Tube, Types K, L, and M, meets Federal and ASTM specifications. Types K and L furnished in hard and soft tempers. Type M, in. and above, furnished in hard temper only. Type K soft temper tube is recom mended for underground water service or fuel lines. Hot water lines of Copper Water Tube lose very little heat to ambient air, hence the use of copper saves fuel. Revere Red-Brass Pipe (Gov't Grade A) or Copper Pipe (both SPS) are recom mended for piping systems where threaded connections are required. Revere Dryseal Copper Tube is dehy drated and sealed. It is commonly used for Refrigeration and Air Conditioning Systems, fuel lines, compressed air lines, and general service work. Furnished in dead soft temper, in. to 1 in. OD, it is easily bent and flared. For Radiant Heating Revere Copper Water Tube, furnished in 60 ft coils is easily bent to form sinuous coils for heating panels. Long, one-piece lengths of copper tube reduce the number of couplings or joints required. - Small diameters of copper tube re quire less thickness of embedment in plaster. For Condensers and Heat Exchangers Revere Cupro-Nickel condenser tube has definitely been found superior for condensers, aftercoolers, and similar heat exchangers. Similar tuDes of Revere Admiralty Metal are widely used. Revere Seamless Copper Tube is com monly used for finned tube coils. For Industrial Piping and the Process Industry Revere produces a wide range of pipe and tube made of copper and copper al loys for industrial use where high resist ance to corrosion is required. Solicitations for assistance in selecting piping material best suited to specific conditions for Fuel Lines, Compressed Air Lines, etc., are welcome. Silver-Brazed Joints Revere ed-Brass Pipe or Copper Pipe is recommended where Silver-Brazed joints are required with standard pipe sizes. Revere Copper Water Tube and stand ard soldered type fittings can also be Silver-Brazed satisfactorily and generally at less cost than heavier pipe. Technical Advisory Service Revere maintains a staff of technical men to assist engineers, designers, and contractors in the selection of suitable Revere products for various applica tions. Their services are available with out obligation. Technical Literature Literature relating to many fields of application for Revere pipe and tube products is available upon request. Two booklets on Radiant Panel Heat ing cover design procedure, and a third is in the form of a non-technical and un biased discussion for lay readers. Revere Copper Water Tube STANDARD DIMENSIONS AND WEIGHTS Type K Type L Type M Size In Id. A M P O 1 8 i J |fW 8 a g* W all 1 ITnh.i 1 W all Th In . H .375 .032 .134 .030 .126 H .500 .049 .269 .036 .198 .025 .145 .625 .049 .344 .040 .286 .028 .204 H .760 .049 .418 .042 .363 H .876 .065 .641 .045 .466 .032 .328 1 1.125 .065 .839 .050 .656 .035 .465 \Yt 1.375 .065 1.04 .055 .884 .042 .682 IH 1.625 .072 1.36 .060 1.14 .049 .940 2 2.125 .083 2.06 .070 1.75 .058 1.46 2.625 .095 2.93 .080 2.48 .065 2.03 3 3.125 .109 4.00 .090 3.33 3M 3.625 .120 5.13 .100 4.29 4 4.125 .134 6.51 .110 5.38 5 5.126 .160 9.67 .125 7.61 3 6.125 .192 13.9 .140 10.2 .072 2.68 .083 3.58 .095] 4.66 .109 6.66 .122 8.93 Air System Equipment and cleaners Air Devices, Inc. Air Diffusers Exhausters Air Filters Filter Holding Frames Hot Water Generators 17 East 42nd St. New York 17, N. Y. Agents in All Principal Cities Designed along entirely new air filter ing principles, the high velocity Agitar 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 permits 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. 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 an dean by catching and holding the dirt. There is no straining action, hence no clogging. HIGH VELOCITY 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. 1/3 LESS SPACE REQUIRED The ability of the FM to filter, with greater efficiency, 50 per cent more air at the high velocity of 432 fpm reduces the number of filter panels required. Now TWO FM's will do the work of THREE ordinary filters . . . K less space required . . . fewer units to be installed . . . fewer units to be serviced . . . overall installa tion and maintenance costs reduced to a minimum. HIGHER EFFICIENCY At the recommended velocities of other leading all metal viscous type filters, the Agitair FM has a higher dust arresting efficiency, which increases as velocities are stepped up. 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 SERVICEABLE LIFE The Agitair FM Filter with its greater dust holding capacity, stays in service for longer periods of time; gives efficient per formance for months instead of weeks or weeks instead of days. Less frequent servicing--and rugged construction combine to give the Agitair FM Filter a much longer serviceable life. 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: Delivered com pletely knocked down for easy assembly, this Agitair holding frame has been espe cially designed for installations requiring an unusually large number of filter panels and where cramped and unusual condi tions place a limitation on available space GREASE FILTERS An efficient, all-metal grease catching, grease holding media. Available in all sizes. 1178 Air System Equipment Air Filter* Air Filter Corporation 108G North Water St. Canadian Representative Milwaukee 2, Wis* DOUGLAS ENGINEERING CO., Ltd. Montreal AIR FILTERS (formerly Aircor) Pennanent-Cleanable GREASE FILTERS AIRSAN AIR FILTERS Industrial Domestic Commercial' AIRSAN VIRO-CRIMP FILTER The specially designed high velocity Airsan Viro-Cnmp 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 comers 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 air evenly over entire filtering area provid ing high filtering efficiency and dust holding capacity with low resistance. Media is viscous type, permanent, clean able, 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 L30I. 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 TypeFi (1 in thick) .060 in. w.g. at 288 fpm Type Fi (2 in. thick) .085 in. w.g. at 288 fpm Type D, (2 in. thick) .09 in. w.g. at 288 fpm Type Dt (4 in. thick) .10 in. w.g. at 288 fpm Type W (2 in. thick) .07 in. w.g. at 300 fpm 98.5% 985% 985% 985% 985% AIRSAN HOLDING FRAMES Made ofiheavy 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 L601. 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 L503. Initial Resistance: .07 in. w.g. at 216 fpm Efficiency Rating: 98.5% Stand. Thickness: 2 in. Write AIR FILTER Corp. for Complete Bulletins 1179 Air System Equipment Air Filters and Cleaners CORPORATION 5200 Harvard Ave., Cleveland, Ohio THE FILTER ENGINEERS Representatives in all principal cities TYPES. AVAILABLE--During the past 27 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 trostatic dirt precipitator, special panel air filters for ventilating, grease, railroad, aircraft and marine applications. ELECTROMAZE ELECTRIC AIR CLEANER 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 efficiency at velocities ranging from 100 fpm to 700 fpm. Recommended velocities for each type of filter furnished on request. For truly super-clean air, the Electro maze electrostatic dirt precipitator is the choice. It removes particles as small as 0.0000039 in. diameter (tenth of a micron), has a rated efficiency exceed ing 90 per cent, as tested by the National Bureau of Standards Discoloration Method. Collects smoke, fumes, pollens, and soot. . Sizes--Filter panels furnished in ac cepted 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, com plete with neoprene seals and choice of locking devices, available for use either singly or drilled for assembly into panel bank. ' Cleaning and recharging filters easily cleaned by washing in hot water contain ing 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 repre sentative on information on any type of filter. Representatives are in most princi pal cities. See classified section of your telephone directory. Electromaze consists of individual pre cipitator cells 4 in., 8 in., or 12 in. in width by 12 in. high. Each cell is a com plete filter with built-in ionizing section. These cells slide into a framework, auto matically making electrical connection by means of a plug in the rear. This unique ``desk drawer" construction provides greater flexibility of size, re duced erection cost, easier cleaning. Electromaze cells can be formed into banks for any cfm requirement to fit any space in increments of 4 in. wide and 12 in. high. The cells are easily cleaned in a separate tank when no duct drain or water connections are available. When duct drains are installed, cells may be flushed clean in place with ordinary city water pressure. Ah System Equipment * CORPORATION All the necessary power pack equipment, indicator lights, door interlock equip ment, etc., is furnished with each in stallation. Air-Maze Corporation manufactures a complete line of viscous impingement type ventilating air filters to meet your requirements within a wide range of limits of pressure drop, velocity, effi ciency, weight, dirt holding capacity and price. A few types are illustrated on this page. THESE FILTERS ARE ALL METAL, WASHABLE, FIRE RE TARDANT. KLEENFLO For average-duty residential and com mercial ventilating applications. Kleenflo panels are baffle impingement type, constructed of layers of crimped galvanized screen. Low initial cost. Available in 1 in., 2 in., and 4 in. thick nesses. TYPE P-5 High velocity panel for handling a large volume of air at low resistance. Par ticularly recommended where space is limited. Available in heavier construc tion for railroad application (Model P-5RR). Also in bronze for maritime use. Available in 2 in. and 2H in. thick nesses. GREASTOP TYPE "B" Widely used in restaurant and hotel kitchens to trap airborne grease and prevent duct fire hazards. Progressive density of media provides large accumu lation without undue restriction of air flow. Available in either "V" or wall angle assemblies or as individual filters. Heavy duty industrial filter for fresh air intakes. Has large dirt holding capacity, high efficiency, low pressure drop. All metal construction. Easy to clean. Holds approximately 2 to 2% times more dust than conventional filters. Available in 2 in. and 4 in. thicknesses. 1181 Air System Equipment Td cieSfere CORPORATION DETROIT AIR FILTER DIVISION DDSTAY DISPOSABLE AIR FILTER PANELS Engineered and constructed to provide greater capacity and longer life. Filter medium is constructed of highly ab sorbent fiber board and designed to change direction of air flow twice as it passes through an outer and inner wafer.' This two-wafer design, as shown below, causes a scrubbing action in the air, forcing it to contact the adhesive coated passageways. As the dust is collected it absorbs ad hesive from the reserve by capillary action. This constantly maintains a. dust-collecting film on the wafer sur faces and substantially increases the filter's life. Full air flow is maintained because the dust's volume decreases when it is wetted out by the adhesive. RESISTANCES Filters available with resistances as low as .155 in. water at 400 . ft per min. (Graphs showing resistance at various velocities are available for each type of filter.) SIZES Dustay filter panels are available in the following standard sizes: 20 x 25 in. 20 x 20 in. 16 x 25 in. 16x 20 in. 16x 23 in. 15x 20 in. Four separate types, varying in the size of the cellular passages, meet a wide range of applications. Three panel thick nesses, 1 in., 2 in., and 4 in. provide varied capacities to suit individual re quirements. Specific information avail able upon request. ADHESIVE "WICK ACTION" PROVIDES GREATER DIRT-HOLDING Odorless and stable. Has extremely CAPACITY high "wetting out" properties which maintain a tacky surface even after Dust is collected on the inside cellular passages of a Dustay filter, not just the face surface alone. Dustay's highly ab large amounts of dust have been collected. sorbent filter medium holds more than For full details see your nearby Air-Maze a pound of adhesive compared to only 3 representative, or write Air-Maze Cor to 6 ounces for other disposable filters. poration, Cleveland 5, Ohio. 1182 Air System Equipment ciSJer. American liter 673 Central Avenue, Louisville 8, Ky. HERmnn nEison muision In Canada: Darling Brothers, Ltd., Montreal, Quebec aar 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-bome 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 1164-1165) 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-Pi 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. 250. 1183 American Air Filter Co., Inc. Air System Equipment Air Filters and Cleaners Electro-Cell Electronic Filter Electro-PL Electromatic Filter Multi-Duty Automatic Filter Electro-Cell Electronic Filter--Differs in concept and design from all other plate type electronic precipitators. In stallation has been simplified, perform ance improved and maintenance advan tages provided. Built in vertical sec tions of two widths--2 ft and 3 ft over-all. Collector plate assemblies are removable; ionizers are hinged and extend the full height of the sections, preventing current loss. A choice of washing collector plate assemblies while in place, or removing assemblies for individual cleaning. 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 preipitation 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 accomodate either armored screen panels or die stamped louver 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. 241-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. 211-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 upto500fpm. Exclusive pyramid pocket media design eliminates through-air pas sages and gives uniformly high efficiency over wide range of air velocities. HV-2 has large dust capacity, long life, and decided advantages where space is limited. Available in three designs. Write for Engineering Bulletin No. 203. AMER-glas Disposable Filter American Tyva HV-t 1184 Airmat Type PL-li American Air Filter Co., Inc. Air System Equipment * ^/aSers AAF ROTO-CLONE DYNAMIC DUST PRECIPITATORS THE ROTO-CLONE is an exclusive, patented development of AAF combin ing the functions of exhausting, separat ing 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 runB, increased power consumption, and higher installation costs. The Roto-Clone, how ever, 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. 274-A. Type D Roto-Clone--a dynamic precipitator which has been successfully applied to the dry collection of nearly every kind of granular industrial process dust. Combines functions of exhauster, dust separator and storage facilities in one com pact, space-saving unit with turbine-like impeller as the only moving part. The impeller's numerous hyperboloid blades produce high mechanical and collection efficiency, which is unaffected by changes in air volume or operating speeds, remaining constant over entire pressure volume range. Adapted to floor or overhead installations and easily relo cated, the Type D's low power consumption and trouble free performance effect real economies in space and operating costs. It is also adapted to individual unit applications at isolated dust sources or to a central system with main dust and branch connections for in-line production. Available in 13 sizes with capacities ranging from 100 to 15,000 cfm. Write for Bulletin No. 272A. Tupe D Roto-Clone Type W Roto-Clone provides the high dust separation effi ciency where extreme fines and exceptionally heavy dust loads are involved. Widely used in the ceramic, chemical and min ing industries and particularly in foundry dust control. Com bining dynamic precipitation with integral sprays, which maintain a flowing film of water on all collecting surfaces, the Type W functions continuously at peak efficiency without interruption for reconditioning or servicing of any kind. It also delivers a constant exhaust air volume, while dust dis charged as sludge creates no secondary dust problems. The compact, self-contained unit including exhauster, collector, and hopper requires minimum space and has a low installation cost. Type W is available in 12 sizes and three arrangements for capacities from 1,000 to 50,000 cfm. Write for Engineer ing Bulletin No. 274A. Type N Roto-Clone is a hydro-static type dynamic precipi tator with dual washing and scrubbing action, engineered originally for efficient control of combustible dust. The Type N Roto-Clone has no moving parts, pumps or auxiliary equip ment, but cleans by forcing air twice through an inverted S-shaped water curtain induced by the forced flow of air through a stationary impeller. Water is constantly reused and water level automatically maintained while entrained moisture in clean air is removed by special wide-spaced elimi nators. There are no interior horizontal surfaces or narrow air passages to allow dust accumulation. Like all RotoClones, the Type N combines the functions of exhausting, separating and storing dust. In the latter case three hopper designs have been developed for different requirements in sludge disposal. Type N is available in 11 sizes with capacity ratings from 750 cfm to 48,000 cfm. Write for Engineering Bulletin No. 277A. 1185 Type W Roto-Clone Type N Roto-Clone  Air Filters / ' Air System Equipment American Solvent Recovery Corp. Cassady and 8th Aves. ----__ Columbus 3, Ohio acsc* Air Recovery Odor Removal Air Purification 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 Filters continuously remove odors and gases by positive adsorption. By physically removing the odors--stale, stuffy "used" air is revitalized for fresh use. Pur Air ACSC Filters will eliminate odor nuisances from fresh air intake, re circulated 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. PUR AIR ACSC FILTERS 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 Filters designed to purify all types of enclosed spaces. The manufacturer of Pur Air ACSC, Filters and Units produces both the activated coconut shell carbon and the complete air purification equipment. This combined, integrated function per mits Pur Air to offer the greatest protection in better quality activated coconut shell carbon at lower initial and maintenance costs. Filter Plate Filler Fold Activated Coconut Shell Carbon PUR AIR FILTER PLATE Pur Air ACSC Filter Plate permits in stalling the most carbon in the smallest space. For precision results, install one (1) Filter Plate per 100 cfm. Air resist ance only 0.1125 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. 1186 American Solvent Recovery Corp. Air Filters Air System Equipment * ^cieanere PUR AIR SALES REPRESENTATIVES Albany, New York, F. R. Foote Co., Inc. Albuquerque, N. M., Boyd Engineering Co., Inc. ^Amarillo, Texas, Snook A Aderton, Inc. .Atlanta, Georgia, Crawley-Gorbandt Co. Baltimo'BE, Md., Lancaster, May A Co. .Binghamton, N. Y., Dudley W. Gregg ; Bibmingham, Ala., 8. C. Bratton Boston, Mass., l. R. Geissenh&iner Buffalo, N. Y., Van Ness Harwood 1 . Butte, Mont., Sullivan Valve A Engr. Co. Charleston, W. Va., Engineering Products Co. Charlotte, N. C., Robert E. Mason Co. Chicago, III., Zintel, Byfield A Co. Cincinnati, O., Russell R. Gannon Co. Cleveland, Ohio, Dan B. Billington Columbus, Ohio, Russell R. Gannon Co. Corpus Christl Tejc, L. S. Pawkett & Co. Dallas, Tex., W. E. Lewis A Co. Dayton, Ohio, Russell R. Gannon Co. Denver, Colorado, E. P. Murr Detroit, Mich., George Q. McNamara, Inc. El Paso, Tex., Boyd Engineering Co. Houston, Tex., Jack Thomas Davis Indianapolis, Ind., Russell R. Gannon Co. Kansas City, Mo., Manufacturers' Sales Co. Little Rock, Abe., J. C. Lewis Co. Los Angeles, Cal., Hess, Greiner A Polland Louisville, Ky., Russell R. Gannon Co. Lubbock, Tex., Snook A Aderton, Inc. Memphis, Tenn., J. B. L&mmons Miami, Florida, Stuart G. Pizie Milwaukee, Wis., Zintel, Byfield A Co. Nashville, Tenn., Cedi G. Acree Newark, N. J., John B. Hewett Co., Inc. New York, N. Y., John B. Hewett Co., Inc. Norfolk, Va., Laurence Trant A Co. Oklahoma City, Okla.,J. M. O'Connor Co. Omaha, Nebraska, D. E. McCulley Peoria, III., Zintel, Byfield A Co. Philadelphia, Pa.. George F. Bertrand Co. Phoenix, Abiz., Boyd Engineering Co. Pittsburgh,- Pa. , E. J. Deckman Co. Portland, Orb., T. C. Langdon Co. Rochester, N. Y., A. R. Bowman Co. Rockford, III., Zintel, Byfield A Co. Salt Lake City, Utah, Williams, Gritton A Wilde San Antonio, Tex., L. S. Pawkett A Co. San Francisco, Cal., E. C. Cooley Co. Seattle, Wash., E. H. Langdon Co. South Portland, Maine, A. E Wallgren Spokane, Wash.. Sullivan Valve A Engr. Co. Toledo, Ohio, Eyster Engineering Co. Tulsa, Okla., J. M. O'Connor Co. Washington, D. C., Lancaster, May A Co. Wichita, Kansas, J. M. O'Connor Co. M-15 CANISTER For replacement on existing systems. For new installations where canister-type ACSC equipment is specified. _> PARTIAL AIR BYPASS For application where available space is limited. Existing ventilation/and air conditioning systems can be equipped without Requiring extensive or costly alterations. AIR FRESH'NER Purifies and removed 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 tories, animal rooms, toilets, locker rooms, libraries, vaults food coolers, etc. 450 cfm and 660 cfm models available. ' Partial Air By Pate FIXED MOUNT UNIT Complete line of self-contained units available for warehouses J5<?Fjt.rlal rooms> 2640 cfm. storages, etc. 12 sizes from 220 cfm to STANDARD EQUIPMENT Pur Air Filters 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 filter for each application and available space. Air Fresh'ner Unit CUSTOM DESIGN Custom design and fabrication service 13 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. 1187 Portable Unit - Fixed Mount Unit Air Filters i Air System Equipment and Cleaners ' Air Recovery W. B. CONNOR ENGINEERING CORP. Danbury, Conn. Representatives in All Principal Cities In Canada: Douglas Engineering Co., Lt<L, Montreal, P. Q. Air Recovery QOREX) Air Purification 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 ' nrtlH"'' 'I'Tjk i 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 33K per cent load reduction would lower the Fig. 1 Dorex Canister 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. Fig. t Typical Canixler Arrangenunt--side view Activated Carbon Traps Gases and Odors Activated carbon removes gases and odors by adsorption--a natural phe nomenon which takes place when air borne 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, 1188 W. B. Connor Engineering Corp. Air Filters Air System Equipment 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 avail able 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 from 0.15 to 0.2 in. wg. Fig. S. Dorex Type C Air Recovery Cell 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 it--consists of removable, perforated, carbon - filled canisters which are mounted in multiple on one or more supporting manifold plates. Fig. 1 shows 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 space limitations. TYPE C--Equipment for Recovering the Freshness of Recirculated Air. Dorex Type C Air Recovery Cells were developed to meet a need for a large capacity, easily handled and installed air purification unit. Each cell measures only 24 in. x 24 in. x8I in. deep and completely purifies 1,000 cfm. They require no more engineer ing than that required for ordinary dust filters and can be mounted right along with them in either flat or "V" arrangement. (Fig. 3) TYPE G--for "Package" Conditioners, Unit Heaters, Refrigerated Spaces, Airplane, Bus, Railway Car, and Marine Installations and Other Systems Where Space Is at a Premium. These compact panels consist of sturdy metal frames, each housing a battery of exposed perforated metal tubes which contain the activated carbon. Standard units of one, two or three tube rows in depth are available in a range of stock sizes for arrangement in air ducts. (Fig. 4) 1189 W. B. Connor Engineering Corp. .. _ _. Air Filters Air System Equipment ana cleaners Air Recovery Ftj. 5. Dorex Typo D Storage Unit TYPE D--For Extending Storage Life and Preserving Produce Quality in Refrigera ted Storage ` ' Type D units are designed to remove ripening gases, disease-causing gases and flavor-impairing odors from the air in cold storages, thus extending storage life and generally preserving produce quality. In apple storages, for instance, they have added 3 to 8 weeks to the keeping time of the fruit. In order to control storage atmosphere adequately and economically. Type I) equipment was engineered to tne following specifications: (1) Constant purification and recirculation of all storeroom air, (2) Thorough mixing of purified air with storage room air, (3) Continuous opera tion independent of other equipment in the storage space, (4) Flexibility in location, and (5) Self-contained unitary design to eliminate costly duct work or alteration. Dorex units are portable and can be floor mounted or hung from walls or ceilings. The directional air jet creates an individual pattern for air mixing and distribution and avoids undue air impact on stored produce or fixtures. With the straightening vanes, the amount of "throw" can be adjusted up to a tight jet that reaches 90 feet away from the unit. The large quantity of air thus handled and the high aspiration it creates (five to six times the volume of supply air) results in a very efficient mixing of room and supply air. Dorex Storage Units are built in sizes and capacities to fit any storage space. All parts are either of non-corrosive metal or protected with corrosion-re sistant coating. (Fig. 5) TYPE PL--For Purifying Compressed Air The _ Type PL Dorex Vapor and Gas Adsorber is designed specially to extract oil vapors, fermentation odors and other gaseous impurities from compressed air. It is especially designed to effectively remove air-entrained gaseous odors and impurities not eliminated by commercial filters, separators, after-coolers or receivers. (Fig. 6) 'ig. 6 Dorex Type PL FOOD SAVER--for Refrigerated Cool ers, Storage The Food Saver is designed to extract gases (odors) from refrigerated coolers and other food storage spaces. Com pact, sturdy construction. One unit serves up to 1000 cu ft of space. (Fig. 7) Fig. 7 Food Sauer Unit AU Dora equipment it catered by U. S. Patentt Not. tfiH,7S7; tfiOSfiSl; tfiOOfiSi; 1103133; 3103131 and othert pending; Canadian Patentt Not. 383.338; {tlfiOO; SOSfill; VHfiM; UOfiSS; JIS.787; USfiSC. 1190 W. B. Connor Engineering Corp. Air Filter* Air System Equipment and cleaner* Air Recovery Nation-wide Sales and Engineering Service The W. B. Connor Engineering Corporation maintains a research laboratory, a staff 'of trained specialists, and district representatives in leading cities. Their services are at the disposal of consulting engineers, architects, air conditioning dealers, and plant engineers. Our staff can assist you in determining whether or not it would be to your advantage to install Dorex in a system you may be designing or improving. Among Thousands of DOREX Users American Tel. & Tel. Co. General Motors Corp. Anheuser-Busch, Inc. Hammermill Paper Co. Boeing Aircraft Co. Lever Bros. Bristol Myers Co. Monsanto Chemical Co. E. I. du Pont de Nemours Pennsylvania R. R. Co, & Co., Inc. Radio Corp. of America E. R. Squibb & Sons Union Carbide & Carbon Corp. Western Electric Mfg. Corp. Western Union Telegraph Co Bulletin 117-C Bulletin 105 A Bulletin 10$ A Bulletin 105A on Type H Equipment and Bulletin 106A on Type G Equipment are handbooks containing all the detailed drawings, charts and text necessary for the selection and ap plication of Air Recovery Equipment and some typical ap plications. They also cover pertinent information on ventila tion, oxygen requirements and recommended fresh air volumes for offices, stores, apartments, hotels, restaurants, night clubs, theaters, hospitals, and schools. Bulletin 117-C contains complete information on Dorex Type C Air Recovery Cells. Air Recovery and Odor Control in Air Conditioning Systems is an unbiased research report prepared for the American Hotel Association by the York Research Corporation of Con necticut on their investigation into the effect of Air Recovery on air quality and conditioning costs. New and Complete Textbook for Only $2 Completely revised and brought up to date, the new edition of Air Conservation Engineering goes thoroughly into the eco nomics, functions and mechanics of Air Recovery. It can help you figure requirements to a wide variety of uses. Contains technical data needed in designing most applications, includ ing valuable air conditioning tables and charts. .Cites actual cases and describes the advantages to Design Engineers, Architects, Plant Engineers and Contractors. For your copies of the FREE literature outlined above or the Air Conservation En gineering. textbook, Air Conservation Engineering, at $2, please send your request to our Engineering Dept, at Danbury, Conn. {See payee 1370 and mi for data on KNO-DRAFT Adjustable Air Diffusers.) 1191 I Air System Equipment << Continental Air Filters, . Inc. P.O. Box 1647 Louisville, Kentucky REVOLUTIONARY NEW FILTER MEDIA USED IN CONTINENTAL AIR FILTERS AUTOMATIC, SELF-CLEANING Air Filters range in rated ca pacities 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 impingement type with a contin uous, rotating filter curtain arranged so that the air passes through both curtains in the same direction, made possible by the`Terris Wheel" action at the top and bottom of the curtain. At the bottom each cell soaks in a semihorizontal position in the oil bath to loosen collected dust, then falls to a vertical position, causinga flushing action counter to the air flow. The dust in the oil settles as sludge to the bottom of the nil tank. The rotation of the curtain is controlled by an automatic electric timer. - Power is. transmitted from a fractional .. horsepower motor through a speed re- dueer and a chain and sprocket"drive, with shear pin protection. MEDIA as used in Continental Filter Cells is composed of dieformed, double corrugated metal strips placed under pressure in non-nesting relationship in sturdy holding frames. Effi ciency of performance results from changes in direction and turbulence created as air streams cross and recross each other while passing through the media, insuring contact of all dust particles with oil coated surfaces. Low resistance results from relatively large, non-clogging passages. UNIT FILTERS utilizing the same type media have the same advantages, with the additional advantage that they may be thoroughly cleaned by a cold water spray. No hot water, detergents, or special equipment are required. Filters are available with handles, latches and holding frames for bank installations, and in-2 in., .and .4 in. thicknesses of popular sizes and capacities. Used without oil, these filters make excellent grease filters, or replacements for glass cells in air washers. . 1192 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 10 ft long and either 1 in. or 2 in. thickness, then fitted into permanent frames. The result in saving is as much as 30 per cent of air filter costs. Changes can be made quickly and the fluffy, fine glass fibers are easy on the hands. 1193 For Complete details, write Dept. HVG-52 Air System Equipment Air Filters and Cleaners Dollinger Corporation Filters for Building Ventilation, Air Conditioning, Engine Intake, Pipelines and Many Other Special Applications. Representatives in Principal Cities 6 Centre Park SfHni 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 effici ency of Staynew Model A-3 is un surpassed among mechanical self-clean ing filters. Operation and Features: Double filter curtains (1) carried on heavy roller chains driven by sprockets keyed to the shafts of the curtain rollers (2). These rollers float oh 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 fear 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-iJ Automatic Filter (numbered features are referred to in accompanying description) tion of curtain travel such that cleaned panels (4) are always on the filtered air side, .^Therefore no dust can be carried across the back or return side of the front curtain t ) be blown off and carried on by the flow of air. Patented, exclusive Staynew Compressed Air Curtain Cleaners (5) are 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 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 parts from accidental damage. Drive motor operates for a few seconds at 15 minute intervals, and compressed air curtain cleaners can be arranged to operate simultaneously. 1194 Dollinger Corporation Air System Equipment clivers STAYNEW PANEL TYPE FILTERS Model WKE Panel and Frame Handle$ and Latches 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 Model 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. Model PVRS Kitchen Range Filter Kitchen Range Filter (Model PVR-3): Solves the problem of grease collection in exhaust hoods over ranges, steam tables or cookers. Eliminates fire hazard and odorous, unsanitary conditions. Features exclusive Staynew "RL" steel filtering medium made in 3 in. deep units. High quality in every re spect, yet low in price. STAYNEW LIQUID FILTER 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 models available to handle up to 1000 gpm. Representatives in Principal Cities Complete Information from Factory on request Model ELS (.Sectional View) FILTERS FOR INTERNAL COMBUSTION ENGINES, COMPRESSORS, PIPE LINES; ALSO DUST COLLECTORS 1195 Air System Equipment Air Filters Chicago r' Farr Cpinpany Manufacturing Engineers . P.O. Box 10187, Airport Station ; . LOS Angeles 45, Calif. ...... - Manufactured under licence by Control Equipment Co., Ltd., Montreal, Canada FAR-AIR* FILTERS FOR ALL TYPES OF INDUSTRIAL USE Hew York THE FAR-AIR FILTERING PRINCIPLE . . . Herringbone-Crimp Media Design . FAR-AIR Filters obtain maximum efficiency through their herringbonecrimp media design. Zinc electroplated wire mesh is formed in alternate layers of flat and herringbone-crimp to make channeled, triangular openings facing the incoming air flow. Design allows greater air flow, turbulence and effi ciency. Dirt builds up in the mesh on the entering side which diverts the air Progressive Loading Feature flow through the channels to clean mesh where the filtering process continues. The accompanying diagram of progres sive dirt loading shows why FAR-AIR filters have-higher performance,' larger dirt holding capacity, lower pressure loss, easier cleanability and reduced maintenance costs. FAR-AIR CAPACITIES .. . Recommended face velocities are 519 fpm although velocities up to 700 fpm may be used. Higher air velocities than recommended results 4n greater pressure loss and a shorter service period. Ve locities lower than 350 fpm are not recommended. The following chart can be used as a guide in estimating FAR-AIR Filter requirements. 4 in. filter thickness has twice the pressure loss of the 2 in. thick ness. ,NET FACE VEL. F.P.M. CAP. C.F.M. Per Sq. In. 346.. 390 ' 433 476 519 563 606 650 693 2.40 2.70 3.00 3.30 3.60 3.90 4.20 4.50 4.80, PRES SURE LOSS CLEAN V $44 0.06' 0.07' 0.09' 0.10' 0.12' 0-14' 0-16' O-IO' 0-21' NOMINAL FILTER SIZE Standard Stocked Filters Other Common Sues 16* x 20*| 16* x 25*| 20* x 20*| 20* x 25* 10* x 20*116* x 16*120* x 30*1 25* x 30* 625 700 780 860 935 1015 1090 1170 1250 FILTER CAPACITY CUBIC FEET PER MINUTE 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 360 405 450 495 540 585 630 680 725 . 485 550 610 670 730 790 855 915 975 1235 1390 1545 1700 1855 2010 2165 2320 2475 1575 1775 . 1970 2170 . 2365 2560 2760 2960 3155 MEDIA DESIGNATION AND APPLICATION Type 44: 14 Jnesh zinc-electroplated steel screen.1 For Ventilation, paint, lint, ink, oil. Type 44F: Coated with vinyl or other special paint. For fume-resistant ap plications. Type 44G: Standard filter, unoiled. For grease arrestance. . Type 44MZ: Screen painted with zinc chromate before and after assembly. Frame hot dip galvanized. Marine type--ventilation application. Type C4C4H: All copper media and filter frame. Corrosion-resistant and water elimination applications. Type A4A4: All aluminum media and filter frame. Stainless steel and monel filters for special applications can be * Trade Mark Reg. supplied on special order. 1196 Air System Equipment Air Filters 'Chicago Farr Company Manufacturing Engineers P.O. Box 101877 Airport Station Los Angles 45,-Galif. Manufactured under license by Control Equipment Co.t Ltd^ Montreal, Canada New York HOLDING FRAMES AND DIMENSIONS FAR-AIR holding frames are made from 16 gage steel and have a baked enamel finish. Felt stripping around the inside flange assures tight filter fit and prevents air by-pass. Frames are" interlocking and easily bolt together to form a rigid framework. Calking be tween frames in a bank is unnecessary. Clips hold filters firmly in place. Brae-: ing is not needed in banks up to 5 filters high by 6 filters wide. Instruction sheets are included in every shipment. STANDARD STOCKED SIZES (Actual) - V and 4' Thickness FILTERS Type'44 and 44H* HOLDING FRAMES Shipping Shipping ' Weight (lbs.) ` - Weight (lbe.) 154 X 194' X 244' x194 X 194' 194 244' 4 114 114 13 16 X 20' 16X25' 20 X20' 20 X 25' 4f 54 84 6 * Includes handles FAR-AIR Filters and Holding Frames can be furnished in practically any size to meet exact specifications. Sizes over 25 in. X 30 in. are not recommended, however, as they are difficult to handle. HOW TO SPECIFY STANDARD TYPE 44 FILTERS & FRAMES Filter Bhall 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 layejs of each per inch, J-in. rod reinforced, and enclosed in a frame of 16 gage steel with flush mitered comers. 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. SELF WASHING FILTERS GREASE ELIMINATORS 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 ment. Washing water and contami nated oil is immediately flushed away, eliminating messy sludge and oil sumps. There is no oil entrainment. Each unit has a safety deluge valve that auto matically prevents fire from passing the unit. Installation is simple and inexpensive. FAR-AIR Grease Eliminators consist of two standard filters in a special adapter with drip pan. These units 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 information on any FAR-AIR product is available on request ... or see Sweet's Architec tural File. 1197 t Air System Equipment ciders Owens-Corning Fiberglas Corporation Toledo 1, Ohio Fiberglas AIR FILTERS WHAT THEY ARE--Fiberglas* Dust-Stop Air Filters are replaceable, impingement-type filters. Dust-Stops are con structed of glass fibers that are non-absorptive, do not shrink or swell. WHERE DUST-STOPS ARE USED-- Dust-Stop Filters are used in all systems in which there is a mechanical movement of air--central heating, ventilating and air-conditioning systems, and mechan ically-circulated warm air furnaces. Composed of numerous glass fibers coated with a viscous adhesive, Dust- Stop Filters catch the dust particles as the air moves through them. , ADVANTAGES OF DUST-STOPS--One of Dust-Stops' great est plus values is fire safety. The fibers cannot bum and will withstand temperatures of 1,000 F. Being glass, the fibers are inorganic, chemically stable and resistant to corrosive vapors. A new, improved dust-catching adhesive is sprayed on the fibers which accounts for longer life with no loss of efficiency. All Dust-Stop Filters are now listed by Underwriters' Laboratories. No special machinery is necessary to install Dust-Stops. Air filtering costs are further cut by Dust-Stops' high capacity to clean the air of dust, dirt, lint and pollen. Dust-Stops are readily adaptable to practically any system. Their low cost and easy installation make Dust-Stops the engineer's preferred filters. FACTS ABOUT DUST-STOPS--Avail able in two standard types: No. 1 (1 inch thick) and No. 2 (2 inches thick). Both types are made in many sizes to fit prac tically every installation. Each filter is faced with a metal grille and bound on the edges with a fiberboard frame. WHERE TO BUY DUST-STOPS--Check yellow pages of your phone book for name of the Dust-Stop distributor in your vi cinity. If unable to locate a distributor write Dept. 44, Owens-Corning Fiberglas Corporation, Toledo 1, Ohio. 'FIBERGLAS and D UST-STOP are trade-marks {Reg. U. S. Pat. OS.) of Owens-Corning Fiberglas Corporation for products mads of or with fibers of glass. .11,98 Air System Equipment Air raters Research Products Corporation Madison 10, Wisconsin AIR FILTERS FOR HEATING AND VENTILATING Greaae Filters for Kitchen Exhaust Systems--Paint Arrestor Pads V'VNvv -<4 \N \\ / A'vV \ V vV> RP AIR FILTERS Controlled turbulence design is pro vided in every RP filter. Scientifically staggered bailies 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. ODOR REMOVAL Exclusive RP Combination dust and odor removal is available in the D-O Air Filter--a replaceable filter--and with D-O Kote, the dust and odor removing ad hesive for application to RP alumaloy washable niters. WASHABLE The RP Alumaloy E Z Kleen Air Filter is an economical selection for many applications. Like all RP washable air filters, this filter is ex tremely easy to clean. 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 REPLACEMENT All RP replacement filters employ a fiber media. The oversize RP "Self Seal" idea was developed due to the handles, lift handles and water soluble filter coat adhesive are available. Efficiency in excess of 99 per cent on grease vapors, gleaming appearance, ease of cleaning and light weight have made ease and safety in handling the exposed media. Soft, resilient, and nonfractur ing, the media only is sold in a refill pad for the famous RP Fiber Self-Seal, Air Filter for central systems and units RP Alumaloy Grease Filters a volume performance leader in its field. A free comprehensive data booklet on kitchen exhaust systems is available. and the RP Snap-In Grid for central systems (illustrated). The filters and pads as well as a conventional cardboard frame filter are available in one and two inch thickness. RP Paint Arrestor Pads, stop and hold overspray in spray booth operation. RP Paint Arrestors cut labor costs and maintenance down-time necessary with conventional paint spray booths. RP Paint arrestors have high overspray removal efficiency, versatility in applica RP Alumaloy Air Filter and Inset Showing Handle tion and low first cost. Loci 1199 Air System Equipment Air Filters and Cleaners H. J. Somers, Inc. 6063 Wabash Ave., Detroit 8, Mich. Agents in All Principal Cities SOMERS Heavy Duty Industrial Filter AU Welded Vet Type Patent No's. 2008800.2130107 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--Do 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. , ^ ....... ....... , 1200 H. J. Somers, Inc. Air System Equipment Jjja SOMERS WASHABLE AIR FILTERS AU Welded Vee Type Stock Sizes Frame Sue Height and Length Frame Depth Filter Surface Square Tnehan Far Average Dry Filter Installations Wet Application a* x 12* 12* x \r 12* x20* 15W x24M' 1hW x24U' I5$i" x24&' wr x 24H' 16* x 20* ie* X 21H' l* x 25* 16* x 25* 16* x 25' 10* x 25* 16* x 25* 16* x 25' ie' x 25' 18' x 18* 18* x 18* 18* x 24' 19H' x 19)4' 19X* IW xx l19WK' 19X' x 19H' WM' x 19)4' IW x 19)4' T 20* x 20* 20* x 20* 2tr x 20* 20* x 20* 20* x 20* 20' x 20* 20* x 20* 20* x 20* 20' x 25' 20' x 25' 20' / x 25' x 25' ^ 20* x 30* 20* x30)4' 23' x 20* 2233gH'' x23H' x 17K' 24' x25H' 25' x 20* 26' x23)4' 26' x23H' 26' x 34' 28' x33M' 29' x33)4' 30* x 15' 30* x 20* 30* x 24' 31' x23H' 3)4* 2)4' 3H' W ZW 2* 3H' r 3' 2* w 3' 3H' 3K' 3)4' 3H' ZW 3H' 3' 2* 3' 3' 3' 3)4' 3H' zW 2* 2)4' 2M' 2H' 3' 34' 3)4' 3H' 3V|' 2* 2H" 3H' zW 3H' 3)2' 3)4' 3)4' 3' 3H' 3H' 2)4' 2H' 3H' 2)4' 3H' 3*2' 3)4' 3' 3K' 288 288 720 1023 1674 480 mo 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 288 CJ.M. 288 C.F.M. 720 C.F.M. 1023 C.F.M. 1674 CJ.M. 480 C.F.M. 1110 CJ Jd. 384 C-FJ4. 816 CJ.M. 480 CJ.M. 624 CJ.M. 864 C.F.M. 1344 C.F.M. 1440 C.F.M. 1632 CJ.M. 1056 C.F.M. 884 CJ.M. 1134 CJ.M. 1080 CJ.M. 480 CJ.M. 819 CJ.M. 936 CJ.M. 995CJ.M. 1053 CJ.M. 1170 CJ.M. 1696 CJ.M. 480C.F.M. 600 CJ.M. 780 CJ.M. 840 CJ.M. 960 CJ.M. 1020 C.F.M. 1200 C.F.M. 1320 CJ.M. 1680 C.F.M. 600 CJ.M. 1020 CJ.M. 1560 CJ.M. 1800 CJ.M. 1800 CJ.M. 2400 CJ.M. 1656 CJ.M. 1621 C.F M 1068 O F M. 1872 C I .M. 1800 C F.M. 936 C.F.M. 936 CJ.M. 2652 CJ.M. 1428 CJ.M. 3046 CJ.M. 1800 CJ.M. 1800 CFM. 1800 CJ.M 3162 C.FJM 144 CJJf. 144 CJ.M. 360 CJ.M. 511 CJJL 837CJ.M. 240 CJJM. 555 CJ-M. 192 CJ.M. 408 C.F.M. 240 CJ.M. 312 C.F.M. 432 CJ.M. 672 C.F.M. 720 C.F.M. 816 C.F.M. 528 CJ.M. 432 CJJf. 567 CJM. 540 CJ.M. 240 C.F.M. 409 CJ.M. 468 CJJi. 497 CJ.M. 526 C.F.M. 585 CJ3f. 848 CJ.M. 240 C.F.M. 300 CJ.M. 390 C.F.M. 420C.F.M. 480 C.F.M. 510CJ.M. 600 C.F.M. 660 C.F.M. 840 CJJI. 300 C.F.M. 510 CJ.M. 780 C.F.M. 900 C.F.M. 900CJJ4. 1200 CJ.M. 828 C.F.M. 810 C.FJ1. 534 C.F.M. 936 C.F.M. 900 CJ.M. 468 C.FJ4. 468 C.F.M. 1326 CJ.M. 714 CJ31. 1520 C.F.M. 900CJ.M. 900CJ.M. 900 CJ31. 1581 CJ.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 Corp., Norge Div.--Borg Warner Kelvinator Corp., York Ice Machine Co. Ships: Amer. Shipbuilding Co., U. S. S. Saratoga, 17. S. N. Lake City, Fla., U. S. N. Daytona Beach, Fla., U. S. N. Vero Beach, Fla., U. S. N. Jacksonville, Fla., Utilities and Municipalities: City of Kenosha, 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. 1201 / ^ Air System Equipment Air Filters TRION, INC.* --1000 Island Avenue, McKees Rocks, Pa. IK METROPOLITAN PITTSBURGH TRION ELECTRIC AIR FILTERS (Electrostatic Precipitator) Trlon Electric Air Filters remove more than 90 per cent of dust, dirt, smoke, pollen and air-borne bacteria from air streams (National Bureau of Standards "blackness" test). Trion manufactures a complete size range of electric air filters for residential, commercial and industrial applications as follows: BUILT-UP UNITS for commercial and industrial use. Complete unit consists of (A) ionizing-collecting cells for specified cfm at required cleaning efficiency; (B) power pack(s) of proper size and capacity, complete with electronic tubes, indicating instruments and magnetic circuit breaker; (C) complete water-wash cleaning system; (D) built-in bank of water proof, dry type mechanical after-filters; (E) rust resistant steel framework, factory assembled, then matched-marked before shipment; (F) door interlock and time delay Bcrews; (I) "Danger High-Voltage" sign; (J) Trion name plate; (K) all high voltage cable and connectors. CUSTOM-BUILT "PACKAGED" UNITS are advantageous in smaller installa tions where space is limited. Models up to 9330 cfm are constructed to specifications as a complete package, including drain pan and access door. . STANDARD "PACKAGED" UNITS for residential and small commercial use are available from stock in 4 sizes up to 4000 cfm at 90 per cent efficiency. Shipped fully assembled, complete with adaptors, interchangeable to accommodate air now from right or left. . ENGINEERED EQUIPMENT designed and manufactured to meet specific re quirements of by-product recovery, nuisance elimination, general purification of air or other gases. Design takes into consideration pressure, temperature, corro sion, dirt-loading, removal of collected dirt. Designer and manufacturers of equipment for electrostatic cleaning and purifying of air and other sen. 1202 AwjSystem Equipment Air raters Vortox Company Claremont, California 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. Vortox Panel Filter with Frame OPERATION. Numerous changes in direction of dust laden air cause the dust particles to impinge 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 locomotives'l It is constructed to withstand the severe usage of locomotive service. It has the exceptional characteristics as in all types of Vortox Panel 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 du3t 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 apd 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 X 2 Actual Outside . Dimensions Inches______ 151 X 19} X 1} 151 X 24 X 1 19} X 19 X 1 19} X 24} X it Capacity Range In CFM** 640 to 950 800 to 1200 800 to 1200 1000 to 1550 Outside Dimensions Of Holding Frames Inches 16} X 20} X 2 16} X 25} X 2 20} X 20} X 2 20} X 25} 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 of the filter. The range of capacities stated above are computed on the basis of average to high velocities applied to the total filter area th* actual outside dirnninrw of Vortox Panel Air Filters* 1203 i - Air System Equipment An 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 Boston 36, Mass. PRECIPITRON AIR CLEANERS PRECIPITRON electronic air cleaners are applied to remove airborne dust and dirt from ventilating air. Used in com mercial establishments, they reduce soil age, redecoration and cleaning costs. Industrially, they reduce contamination of processes and provide the cleaned atmosphere necessary for precision manufacturing. Horizontal Air Flow Designed for installation in ducts--man ual washing. Available in capacities of 1200 cfm and up with efficiencies of 90 or 86 per cent by Blackness Test. Power supply--115 volts, single phase, 60 or 60 cycle. Semi-automatic Wash Similar to horizontal air flow but equip ped to perform the functions of washing, draining and applying adhesive auto matically. Units for 90 per cent effi ciency 40,000 cfm up, may have pro visions for wiv'hing the PRECIPITRON without interrupting the air cleaning. In cases where the cleaner can be shut down for washing, units are available for either 90 or 85 per cent efficiency, in capacities of 24,000 cfm and up. Encased Precipitron Horizontal Airflow Commercial Precipitron With Semi-Automatic Wash Vertical Air Flow A PRECIPITRON arrangement for ver tical, up or down, air flow--manual washing. Particularly suited to small and medium size installations where floor space is at a premium. Capacities of 1200 to 9600 cfm with efficiencies of 90 or 85 per cent. 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. Available with built-in fan for individual machine application, without fan for group col lection system. Capacity--600 cfm. Home Unit Designed for residential use when con nected in return air duct of forced warm air heating system. Capacity-1200 to 1500 cfm; efficiency 90 per cent. Operates from house current witn total power con sumption of 60 watts. ' 1204 ....Commercial Vertical Airflow Unit Air System Equipment At niters Wilson & Co., Inc. AIR FILTER DIVISION 4100 S. Ashland Ave. Chicago 9, Illinois A Product of t\ n\ n ------- W'N'V7 ,,4-- H.t*-mA - 4'* 4> < 4 > <>4*44> -4 4 - . <' ;V' f* >4 V 4 V-4 4 i4 P-A 4 4 > A 4 4 V 4 >4 a -< 4 r < *-4 >~4 > >4 . y-4 >4 V< . 4 V 4 *-4 -< p-4 < * >-4 >4 >-4 >- >4 >4 4 -4 y4 .* 4 >-4y 4 ><y-4 *-4 - . a >< < >-< w-4 '4 y <4>4 * *< < -<-<v a V,4 y4 . y y 4 4 ->-4' *. 4 V-4 \V 4 y-4 y 4 y<>--4MV^-M>4 ; >-< >*4 -< ->. y* 4. >-* . y* v 4 4 y 4, y-* ' fc-4 ' ' __ 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 ani mal hair, scientifically bound, EDGESEAL adds an extra 20 per cent of face filtering area. Even greater is the addi tion to holding capacity. 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.M7 at 300 F.P.M, ACTUAL DIMENSIONS Width Length Thickness ACTUAL DIMENSIONS Width Length Thickness 10"xlPx2" 10* x 20* x 2* 15*s 20*x 2* 15* x 20* a 2* 16' x 25' x 2* 20*x20*x2* 20* x 25* x 2* 20#x30*x2' 200 400 600 640 800 800 1000 1200 10* w I454* 1554' 1654* W* 1954* 1954* 10* 1054* 1954* IBM' 24M' 19M' 24M' 2954* 2* 2 r Y 2* r Y 10M' 10M' 15M' 16M' 16M' 20M' 20M' 2054' 10M' 20M' 20M' 20H' 25M' 20M' 25M' 3054' 2* y Y 2* Y Y Y Y WILSON HAIR FILTERS are manufactured in all regular and special sizes in 2 in. and 2 in. thicknesses in and M in. thickness provided when required.) 1205 ' Air System Equipment tSSSI Manufacturing Company 3130-36 Carroll Ave., Chicago 12, 111. Representatives in all principal cities Water cooling systems and nozzles... a size and type for every purpose Binks atmospheric spray cooling towers Small sizes, in a variety of standard units 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 SB. Binks horizontal induced draft cooling towers 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 diameter. Fre quently installed in multiples for large capacities. Ask for Bulletin 34- Binks spray filled forced draft towers Small, compact, quiet, specially suitable for use with packaged air conditioners. Nineteen sizes for systems ranging from 3 to 21 tons of refrigeration. Ask for Bulletin 35. Binks redwood atmospheric cooling towers In single section units of solid redwood construction, are built in seven standard sizes to handle normal capacities of 20 to 125 gpm of cooling water. Ask for Bulletin 40. Binks steel cased Induced draft cooling towers Towers of this type are of the spray filled or deck filled type--made in 20 standard sizes of sq ft rated area. Larger models are engineered to specification. Air propulsion assemblies for either type can be arranged for V-belt or reduction gear drive, as required. Ask for 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 38. 1206 Binks Manufacturing Co.Air System Equipment xiffiSS Binks non-dogging Rotojet spray nozzles Non-clogging Rotojet nozzles are the heart of every Binks water cooling system. They account largely for the efficiency and satisfactory operation of Binks water cooling installations. In addition to cooling tower applications, Binks Rotojet 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 tern. Standard small and medium Rotojet nozzles are machined from brass bar stock, but can be made on special order from monel, stainless steel, or other machin 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 threads and orifices. These nozzles may be cast in other metals for special purposes. Binks small and medium capadty Rotojet nozzles To fit to % in. pipe connections. Regularly supplied in brass, with male or femme 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. Full data is contained in Bulletins Nos. 10 and 11. Binks heavy-duty Rotojet nozzles To fit 1 to 2J^ 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). Ask for Bulletin No. IB. Binks Spra-Rite nozzles Produce a solid mass cone spray pattern. Small sizes for 14 to % in. connections are widely usedfor air washing, cooling, brine refrigeration, rapid evaporation processes, filtering systems, chemicals, etc. Bulletin 19. Binks large capacity Spra-Rite nozzles To fit 1 to 3 in. connections meet a variety of heavy-duty uses in blast furnace gas washers, vibrating and revolving screen coal and gravel washers and water cooling. Bulletin 19. 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 deliver round or flat spray and are designed for use with auto matic siphon or pressure feed installations. Described in Bulletin No. 16. Engineering service and technical bulletins Binks engineering service and facilities are available without obligation or cost to architects, heating and ventilating engineers and builders. We welcome the op portunity to be of service in planning and installing cooling systems that will fully meet every requirement of performance. Give us the details of your problem and we will submit our suggestions. Technical bulletins describing Binks water cooling systems and industrial nozzles are available for all units described on these pages. Write for the ones that will be useful to you. They will be mailed promptly, without obligation. 1207 Air System Equipment cooling Towers The Fluor Corporation, Ltd. 2500 South Atlantic Blvd. Los Angeles 22, California District Offices New York City Boston - Pittsburgh * Chicago - Tulsa - Houston - San Francisco - Countertlo Induced Draft Cooling Towera--Aerator Natural Draft Cooling Toweia Thirty years of intensive development in -the design, fabrication and erection of cooling towers enable Fluor to offer both natural draft and induced draft cooling towers with comparable first cost based on comparable performance, guaranteed ' cooling efficiency, and dependable, long life service. COUNTERFLO INDUCED DRAFT COOLING TOWERS DESIGN: Octagonal or rectangular shape with counter-flow design that per mits longer air-water contact. Distribu tion system available in either up-spray or down-spray types. Octagonal shape eliminates "dead" corners and is comple mentary to modern building or plant design. PERFORMANCE: Counter-flow principle plus efficient distribution system pro vides maximum performance far m excess of cross-flow or concurrent types. Dis tribution system in the upper portion of tower "flashes off" approximately 30 per cent of heat load before water starts down through tower. Performance to cus tomer'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 tip. 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 6 in. x 6 in. beams. Two-inch red wood in fan deck and stack. Internal gusset plate and bolt-type structural joint take both'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-bulb 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 20 to 25 years. . MANUFACTURE: Completely prefabricated. Timber joint structural connectors meet the most rigid building code requirements. Structure is composed of select redwood. Members are 4 in. x 4 in. or greater. Aerator panels are m. x 3 in. bat tens supported on 2 in. x 4 in. transcords. Hardware according to customer specification. 1208 Air System Equipment cooua* Towers Foster Wheeler Corporation 165 Broadway, New York 6, N. Y. . District Offices Atlanta Boston Chicago Cincinnati Cleveland Dallas Detroit Houston Kansas Citt, Mo. Los Angeles Philadelphia Pittsburgh San Francisco Washington, D. C. Foster. .Wheeler engineers have had O many years of experience in the design and construction of high efficiency cool ing towers for service in any geographical location and under all climatic condi tions. These cooling towers meet the requirements of a variety of industrial needs such as those encountered in chemical plants, public utilities, textile manufacture, office buildings, depart ment stores, and oil refineries. Foster Wheeler offers cooling towers of all types and capacities employing natural, forced, or induced draft. Recommenda tions are made only after careful study of . the customer's particular requirements. Vacuum Refrigeration Schematic diagram showing arrange ment of a typical vacuum refrigeration system. These systems, which cool water by subjecting it to high vacuum, supply chilled water for air conditioning or refrigeration. When a sufficient quan tity of steam is available, vacuum refrigeration systems have several out standing advantages such as low initial cost, low maintenance cost, absence of toxic and explosive refrigerants and, ex clusive of pumps, no moving parts. En tire unit designed and constructed by Foster Wheeler. 1209 Air System Equipment cooling Towers Lilie-Hoffmann Cooling Towers, Inc. Exclusive Builders of Cooling Towers for SO Years 4239 Duncan Ave., St. Louis 10, Mo. Two Modern Plants--St. Louis, Mo., and PLAnmew, 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. FORCED DRAFT TOWER 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. Rigidly braced and tied together to pre vent warping and buckling. Withstand wind pressures up to 100 mph without use of guy lines. Three-tier zigzag pattern spray elimina tor cuts drift loss to minimum. Fan open ings covered by galvanized screenwire. Towers built in single or multiple cells. Continuous design improvement, based on installation studies, presents record of unfailing operation. 1210 Air System Equipment The Marley Company, Inc. 222 W. Gregory, Kansas City 5, Missouri Representatives in All Principal (Sties (Consult Classified Phone Directory) Water Cooling Towers and DriCoolers of Ail Types and Capacities. Spray Nozzles MARLEY DOUBLE-FLOW AQUATOWER . . . The new "low silhouette," low pumping head tower for air conditioning and refrigeration jobs of 50 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 seven standard sizes of all steel or wood with asbestos cement board casing, it has open distribution, full height louvered sides, and all fittings and mechanical equipment are com pletely accessible. Write for Bulletin DFA-52. 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. More than 7,000 Aquatowers are now in service throughout the country. They are carried in stock, shipped completely assembled and require no field erec tion. Large models may be readily disassembled to facilitate handling. Write for Bulletin AQ-52. 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, theaters, 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 100-52 or 200-52. MARLEY Conventional . .. These structurally excellent COUNTER-FLOW towers assure peak performance and op erating economy. Built to high structural standards, they are equipped with Marley mechanical units and other exclusive Marley features. Marley Conventional towers meet every water cooling application and are also adaptable to indirect cooling with atmospheric sections. Available in redwood, steel or asbestos board casing. Medium to large capacity. Write for Bulletin C-52. ~Z MARLEY Double-Flow .. . Has these advanced features in -! cooling tower design: Horizontal air-flow through full height louver walls, Open distribution system, Low pumping head, Minimum draft loss, Double service from each fan unit, Pa tented, nail-less filling which retains correct alignment without ^ fasteners, Marley designed and built mechanical equipment, ] Utmost flexibility, Safe operation and low maintenance cost. Available in redwood or asbestos board casing. Double-Flows I are used wherever large gallonage of water must be cooled j economically and efficiently. Write for Bulletin DF-52. MARLEY Nozzles . . . Marley patented, bronze Spray Nozzles achieve the fundamental requirement of every spray installa tion ... a maximum breakup at lowest pressure . . . without moving parts. Three styles, one piece, two piece, humidifying. Write for Bulletin SN3-52. 1211 Air System Equipment cooling Towers equipment division j. F. Pritchard & Company Dept. 230,908 Grand Ave., Kansas City 6, Missouri Houston, St. Louis, Chicago, Pittsburgh, Tulsa, New York Representatives in Other Principal Cities THREE LEADING LINES--COOLING TOWERS, HEATING EXCHANGERS, Gas Equipment for FIVE MAJOR FIELDS--Chemical, Natural Gas, Petroleum, Power and Refrigeration COOLING TOWERS Models for every capacity and applica tion. Guaranteed performance ratings assure trouble-free performance and long life. Many patented features not available in any other tower. Specifica tions, prices and ratings furnished promptly, without obligation. (Left) SERIES H INDUCED DRAFT TOWER. Horizontal flow design. Es pecially adapted to air conditioning, refrigeration, and industrial heat loads. Steel or Redwood construction. For roof or ground-level installations. Pre fabricated for easy assembly. 30 to 100 tons capacity. (Center) SERIES Q INDUCED DRAFT TOWER. Vertical counterflow model. Especially adapted to air conditioning, refrigeration and industrial heat loads. For roof or ground-level installations. 100 to 1500 tons capacity. (Right) SERIES G INDUCED DRAFT COUNTERFLOW TOWER. Designed for medium capacity industrial applica tions. Uniform air distribution for maximum cooling effect. 20 to 100 tons. Prefabricated, Redwood or steel. (Near Right) SERIES PB "COTOPACK" INDUCED DRAFT COOLING TOWERS. Ideally suited for indoor or outdoor service on small air conditioning or refrigeration installations as well as jacket water and air compressor cooling. Shipped assembled. 6 to 20 tons ca pacity. (Above Right) SERIES SR COTOSPRAY* TOWERS. Type "G" is pictured above right. Type "F" also available. For roof or ground-level installation. Designed for air conditioning and refrigeration installations requiring 3 to 35 tons capacity. Simple bolted assembly. Finest Redwood with steel pipe distribution system. Louvers lift out for easy access to interior. Series SRE for specific heavy duty indus trial applications also available. Pritchard Accessory Equipment includes: SEALDFLOW* Fan Drives, COTO SPRAY* Nozzles and COTOSPRINK* Distributors, POWairSAVER* Fans MINIM- ICER* Louvers. WRITE FOR BULLETINS * Registered trade names for specialized equipment produced by J. F. Pritehard & Co. 1212 . Ah System Equipment xj5 Water Cooling Equipment Co. New Hampshire Ave. and Weber Rd. St. Louis 23, Mo. Fabricating Plants St. Louis, Mo. Abcata, Cal. Houston, Texas Representatives In Twenty Eight Principal Cities COOLING TOWER SELECTION is dependent upon many factors and variables including type of service, water pollu tion, wet bulb air temperature, temperature of water to be cooled, final temperature required, power source, location of proposed installation, adjacent equipment, and many other variables peculiar to each proposed installation. Therefore it is extremely difficult for an engineer to select the proper type and size of water cooling equipment without the assist ance of a WCEC engineer. __ _ Selection of the type of cooling tower should not be made on the initial cost basis alone, but instead on the cost of providing sufficient water cooling capacity to as sure low operating temperature and high performance. OUTSTANDING DESIGN FEATURES--(1) Patented Cast-iron Timber Connectors which develop the full strength of the timber joints, an accomplishment almost im possible to achieve otherwise. (2) Patented Redwood Drift Eliminators of the new multiple effect type remove the entrained moisture carried by the air. The elimi nator blades are separated by spacers so arranged that the blades are free to expand and contract to avoid warping. No nails or metal fastenings are used. (3) Patented Non-Clogging Low Pressure Spray Nozzles provide maximum water break-up at lowest possible pressure. A true paraboloid of revolution is maintained in the whirl chamber thereby eliminating a constricted orifice which is the principal cause of clogging. (4) Improved Nailless Grid Type Fill repeatedly interrupts and refilms the water in its passage through the tower. The filling members are arranged to obtain maximum possible retardation of the descending water to allow a long and intimate exposure of the water to the air rising through the tower. The filling guides the air to completely utilize its heat removing capacity with minimum resistance. No nails are used in the filling. MECHANICAL DRAFT TYPE COOLING TOWERS, either Induced Draft or Forced Draft, are designed for more exacting performance and operate independent of wind velocity. Overall plant economy results from cooler water possible with controlled volume of air. Three Types of Induced Draft Systems are built (1) Contraflow, (2) Multi-Stage, and (3) Low Head. Fans located on the top of the tower provide vertical movement of air across the filling, discharging air at high velocity to prevent recirculation. Contraflow Type are designed for large cooling systems needed by industry. Water distribution is by gravity splash system. Most extremely large installations are of this type. Multi-Stage Type has been designed by WCEC to meet the demand for extreme performance and low operation and maintenance costs. They employ low pressure head and have less air resistance, longer air travel, and consequently cooler water. WLH Low Head Series Towers, especially suitable for medium duty are compact, low in height, and are shipped completely pre-fabricated, ready for assembly, with minimum field labor. Twelve sizes are manufactured. Forced Draft Systems, especially suitable for corrosive or polluted waters, operate on the same principal as Induced Draft Systems except that the fans are located in the air entrance. WATERFALL SPRAY TYPE ATMOSPHERIC COOLING TOWERS are fabricated in from 5 to 1,000 gpm capacity. Spray nozzles, break-up the water with cooling performed by air movement controlled solely by atmospheric conditions. Thirty- three sizes are pre-fabricated for easy assembly. Deck Type Atmospheric Towers are manufactured in various sizes for any capacity or cooling requirement. The size is changed by varying the number of bays and cooling decks. All are made of All Heart California Redwood or other suitable material. ENGINEERING ASSISTANCE is available to help solve the cooling problems in your plant. Our engineering staff is prepared to work with you in the proper selec tion of a water cooling tower that will meet your requirements with (1) guaranteed maximum efficiency, (2) economy of operation, (3) conservation of water. Write for our Catalog. 1213 Air System Equipment oSt?dlf,il1* American Moistening Company . Established 1888 Providence 1, R. I. - Atlanta, Ga. Boston, Mass. Camden, N. J. Charlotte, N. C, Air Conditioning Systems--Humidification, Evaporative Cooling and Central Station Because Amco installs both ductless and duct systems, you can rely on Amco engi neers to give you sound, impartial advice. If you already have a modem,.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 the 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. 1214 ' Air System Equipment spn, 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- AIR CONDITIONING AND OIL BURNER NOZZLES Water Capacity In Gallons per Hour Fig.FSO 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 60 .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 H in. or 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 RedJBrass and in pipe sizes 1 in., in., 2 in., and in. Capaci ties from 4.1 to 88 gpm at 7 lb pressure. Write for Detailed Catalogs 1215 i . Air System Equipment cweSS?" Snrt"" ACME INDUSTRIES, INC. Jackson, Michigan Representatives in Principal Cities CONTINUOUSLY SERVING THE REFRIGERATION INDUSTRY SINCE 1919 FREON CONDENSERS AMMONIA CONDENSERS Shell and Tube type for use with Am monia, Freon or other Refrigerants. Standard or special designs to meet vary ing water temperatures available and condensing temperatures desired. EVAPORATIVE CONDENSERS All prime surface for Freon or Ammonia Refrigerants--Heavy Gage Sheet Metal Casings, especially processed for Maxi mum Resistance to Rust and Corrosion. Capacities to 100 tons. All fabricated steel parts are now hot-dip galvanized after fabrication. DRY-EX COOLERS Refrigerant in Tubes, Solution baffled through shell. For cooling water, brine. Glycols or Alcohols by direct expansion of refrigerant. HEAT INTERCHANGERS Shell and coil units for small capacities, shell and tube units for large installa tions. 16 standard models from one ton to 180 tons capacity. BLO-COLD INDUSTRIAL UNIT COOLERS Blo-Cold Models are available for either medium temperature or low-temperature applications. All fabricated steel parts are hot-dip galvanized after fabrication. COOLING TOWERS Twelve sizes of induced draft cooling towers to fit practically any application. Sturdily built, hot dipped galvanized for long life. Acme Industries, Inc. also manufacture Flooded Water and Brine Coolers, Hi-Peak Water Coolers, Pipe Coils, Flow-Cold Liquid Chillers, Oil Separators, Receivers and Fin Coils. . WRITE FOR CATALOG ON ANY PRODUCT 1216 Air System Equipment f5>ce*nsfer /^cropin Corporation 410 So. Geddes Street Syracuse 1, N. Y. Aerofin Standardized Light-weight Heat Exchange Surface Branch Offices Boston, Cleveland, Chicago, New York, Philadelphia, Detroit, Dallas, San Francisco and Montreal 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 field. 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 Bq ft to 26.28 sq ft. . Pig.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--% 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 ized iron. Design--Constructed with headers on Aerofin Non-freeze heateT (Fig. 1) is opposite ends making possible installa non-freeze, non-stratifying spiral fin coil tion of units with tubes horizontal or built into casing for air conditioning vertical. 1217 Aerofin Corporation Air System Equipment stSf^fnrfer Aerofin Corporation Air System Equipment Heat Transfer Surface 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. Fit. i Fig. 6 Aerofin Heavy-Duty Industrial Heating Coil (Fig. 4) for use where extra-rugged Narrow Width Aerofin: (Fig. 6) recom coil is needed for close control. Steam mended for water cooling or for flooded pressures from 25 to 450 lb gauge; tem Freon systems. Made in straight tubes peratures to 550 F. only with headers on opposite ends, joints Headers--Pressed steel. between headers and tubing being Tubing--1 in. O.D. heavy copper. brazed. Construction similar to Flexi- Casings--12-gauge galvanized iron. tube Aekofin. . 1218 Fig. 7 . Aerofin Continuous Tube Water Coils (Fig. 7) are designed for air cooling by circulating cold water through the Aeboftn 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. $ 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 No other foundation required. Aerofin Cleanable Tube Units (Fig. 8) Sale: Aerofin is sold only by manu for cooling only made with headers re facturers of nationally advertised Fan movable to permit cleaning tubes. Recommended for use where sediment or scale forming chemicals are present in the^cooling water. Headers--Fabricated steel. System Apparatus. List upon request. Write Syracuse for Heating Bulletin H-4S; Direct Expansion Bulletin DE-48-1 on refrigeration type units; Continuous Tube Bulletin C. T. 39-2 for Water Cool Tubing--Copper or admiralty. ing Coils; or pamphlet on Cleanable Type Casings--Copper or galvanized iron. Aerofin for cooling. 1219 I Air System Equipment Heat Transfer Surface The G & O Manufacturing Company 138 Winchester Avenue New Haven 8, Connecticut G30 . SQUARE FIN TUBING STRAIGHT LENGTHS--U-BENDS--CONTINUOUS COILS THE use of INDIVIDUAL fins results in high efficiency in heat transfer from primary tube surface to secondary fin surface. Fins of any size or shape may be obtained giving any desired proportion of primary and secondary surface. A square fin has about 30 per cent greater surface than a round fin of a diameter equal to one side of the square. Individual fins permit of any fin spacing: also, of using fins in groups at intervals along tubes. STANDARD sizes 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 temperature alloy--complete thermal contact. C--Free air-flow passages; non-clogging. O.D. of Tube w w w H' H' H' 1* W Fin Size Fin Spac Surface per ing per Inch Linear Foot H'aq. W r'd. IX'X 2* oblong 1H' r'd. 1M' r'd. IM'sqSH'oq. 2H* r'd. 6 0.80 aq. ft: 6 0.60 sq. ft 6 3.65 sq. ft. 6 0.87 aq. ft. 6 1.55 aq. ft. 6 2.40 aq. ft. 6 4.00 aq. ft. 4 2.33 sq. It. RADIATING ELEMENTS FOR ALL HEAT TRANSFER PURPOSES G&O Finned Radiation Coils for industrial applications are available in a wide range of sizes. 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 I*"!* 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, 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. |'tl Proem IS. Fin Tube Condenser. P* Freon Cooler (Dry Expansion Type) 2-circuit construction. All I** Coolers built in accordance with the ASME Code, Par. U-69, for unfired pressure vessels. Universal Tvpo B Standard No. 10 Send for Catalog and Price List 1220 P* Freon Cooler (Dry Expansion Type) 3-circuit construction for 200-ton 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. 1221 I ^ Air System Equipment Cons KRITZER RADIANT COILS, INC. "IF IT'S KRITZER, IT'S RIGHT SIR" 2909A LAWRENCE AVENUE CHICAGO 25, ILLINOIS KRITZER "FIN-TUBE" RADIANT COILS Kritzer "FIN-TUBE" Radiant Coils introduce a new, im proved method of radiant heating. They are enclosed in joist or stud spaces, concealed but not imbedded in structural ma terials. They warm the air in these spaces, and indirectly warm ceilings, floors or walls to produce radiant panels for all areas. No concentration of heat in one spot. Kritzer com bines low first cost with lower installation costs. Installation begun and finished when framing is up, and before plastering. Coils are installed crosswise to joists--finned sections lying be tween joists slightly above plaster; tubing suspended on hang ers with metal clad insulating sleeves. Simple construction. A single 36 in. copper tube is mechanically bonded to 134 in. x 3 in. aluminum fins, in sections for highly multiplied heat transfer surface. These compact, attractive baseboards supply heat both by ra diation and convection--allow maximum use of floor space-- harmonize with any interior decoration. Standard Baseboard Coils are made with aluminum fins 2 in. x 534 in. mechanically bonded to two 34 in copper tubes. Universal Coils are made with 234 in. x 3% in. fins in steel, aluminum or copper on 1 in. or. 134 in. diameter steel pipe or copper tubing. Installation re quires only three quick, easy steps. (1) Steel back plate is placed against wall on finished floor and fastened. (2) Elements are then snapped into place. (3) Front cover is simply snapped in place and end enclosures installed where required. Damper with control knob is available as optional equipment. Furnished in standard 10 ft, sections easily cut on the job, or cut to length on order. KRITZER "FIN-PIPE" COMMERCIAL HEATING COILS More Btu's for less time, labor and dollars! Engineered for greater efficiency and faster installation. Kritzer "FIN-PIPE" Coil sections easily equal the heat output of equipment costing over twice as much, yet Kritzer Radia tion more than cuts in half the time and labor necessary for installation. Fins grip pipe with specially designed deep col lars to assure better heat transfer and a permanent, positive mechanical grip. Pipe sections are furnished with chamfered ends, ready for welding, or threaded with modern, improved chaser type die heads that give clean, sharp threads so necessary for fast, leak-proof connections. A vari ety of covers snap on to wall hangers but do not touch fins. Kritzer "FIN-PIPE" Commercial Radiation is available in a va- _ Slope top cover 334riety of sizes:2 in.; 134 in.;l in. steel pipe KriucTeTm- or copper tube with 434 is. square, 'n mmial Coil square or 234 x 334 in- fins of steel, alumi numor copper, spaced24,32, or48 per foot. 1222 Air System Equipment Fin Tubing and Coils The Roine-Turney Radiator Company Erie Boulevard. East Rome, N. Y. Manufacturers of "Ro-Fin" Tubes for Efficient Heat Transfer Ik Pnn.Anri.PBTA 8BB W. H. BuKTEK, 1205 Hamilton St. In Sr. Louis bee Brass and Copper Sales Co., 2817 Euclid Aye. . Ik Buffalo see J. Landers, 170 Franklin St. "Ro-Fin" Extended Surface Helical Fin Tubing for Heat Transfer Nearly 100 sizes of "Ro-Fin" Extended Helical Fin Tubing are in production: straight lengths, coils, U-bends, coils-wifchin-coils, with or without threaded end connection, or for standard flare connections. "Ro-Fin" tubes are adaptable for all types of heat transfer work, and are made to the individual specifications of each order. Complete range of sizes includes tube diameters (outside diameter) from f in. to If in., fin widths from ^ in. to f in. Number of fins per inch: 3 to 19. "RoFin" tubes can be furnished in continu ous lengths, with or without joints. Straight lengths furnished up to 25 ft long. "Ro-Fin " lubes in a convector radiator for heating homes, office*, churches, schools. Cutaway section showing replaceable header construction of copper heating dement. Write for information on yonr heat transfer problems for: Refrigeration Condensers Steam Condensers Fluid Recovery Condensers Fan-Type Unit Heaters Concealed Radiation Convectors Diesel Engine Cooling Baseboard Radiation 1223 Air System Equipment. R^gre The Vulcan Radiator Company 22 Francis Avenue Hartford-6, Conn. Representatives in Principal Cities Vulcan Radiation is used in railroad cars, ships, hospitals, schools, churches, homes and industrial plants. Available in steel or copper . . . easy to install . . . light in weight . . . requires few fittings and sup ports . . . tube ends threaded or cham fered for welding. Heat distribution is uniform. Steel radiation comes in two sizes ... 2 in. IPS, rated--5i sq ft per lineal ft at 1 lb steam and 70 deg air . . . for li in. IPS see illustration--this size also available in copper. Illustrated catalog available. Standard Grille Cover Linovector Covers Type P Type S 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 ' vsponds quickly to thermostatic control. Full heat output is obtained almost immcdi- ately after steam is supplied. Since most of the heat is given off by convection ,'tbe residt]iSjEVEN, UNIFORM HEAT from floor to ceiling. Vulcan Baseboard Radiation ... fin-on- tube construction with grille covers com bines 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 supports. Comes in two sizes . . . 1} in. IPS . . . steel fins 2f in. wide by 3| in. high ... for 1 in. IPS, see illustration. Also available in cop per. Illustrated catalog available. 1 in IPS Pal. No. tJt&ifiiS Radi-Vector Coven Type K Type L l*B*R ratings for Vulcan Radi-Vector available in Catalog No. 68. 1224 Air System Equipment ?"* BAKER REFRIGERATION CORPORATION South Windham, Maine Offices, Warehouses and Parts Depots in Principal Cities Air Conditioning Refrigeration Products: Air conditioning and refrigeration (central plant and unit equipment). Condensers--evaporative or shell ana tube, wide capacity range. Cooling Units-- for every requirement, for all refrigerants. Liquid Receivers--for ammonia or Freon, with positive liquid seal. Valves and Fittings--a complete line. FREON 1. Baker Compressors, li to 60 hp, feature high efficiency at low operating cost. Timken bearings, forced feed lubrication, gear-type oil pump, posi tive shaft seal promote long life. 2. Baker Condensing Units. } to 60 hp, are engineered with matched com ponents to assure efficient, trouble free operation for every application. Com pressor units, 1} to 60 hp. AMMONIA - - upph _ capacity reduction control down to 33} per cent. Double suction control for operation at two different temperatures is available on special order. ,_ 4. Baker Compressor Units. 2 to 15 hp, feature automatic motor control with overload and low voltage protection. Complete Condensing Units also available from 2 to 15 ton capacities, ready for installation. _ 5. Baker Booster Compressors for two-stage operation on the low side in low temperature applications. Forced-feed lubrication and balanced fly wheel for "V" belt drive. Compact design requires a minimum of space. 6. BAKERAIRE--Delivers maximum cooling per horsepower input. Famous Baker hermetic compressor in 3,5,7} and 10 ton capacities. 4-way air discharge, new Sphericoil condenser, humidity con trol, spring-mounted compressor. 7. CENTRAL-AIR--A complete unit air conditioner in capacities from 5 to 40 tons with built-in evaporative condenser. Factory assembled and tested, delivered ready to operate. Simplified installation keeps first cost low. Fully automatic controls. 1225 Air System Equipment Refrigerating Machinery Baltimore Aircoil Company, Inc. 2615 Mathews "Street Baltimore 18, Maryland Manufacturers of Evaporative Condensers and Cooling Towers BALTIMORE FAN COMPANY (A Division of Baltimore Aircoil Company, Inc.) Manufacturers of Propeller Fan Wheels 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: 3 TR to 100 TR. Model "PT" Cooling Tower: Vertical propeller fan type. . .outdoor installa tion only. Capacities: 3 TR to 100 TR. Model "U" Moid "UL" Model "U" Evaporative Condenser: Centrifugal fan type. . .indoor or out door installation. . .Freon or Ammonia. Capacities: 10 TR to 100 TR. Model "UT" Cooling Tower: Centrifu gal fan type. . .indoor or outdoor in stallation. Capacities: 10 to 100 TR. Model "UL" Evaporative Condenser: Centrifugal fan type. . .indoor or out door installation. . .Freon or Ammonia. Capacities: 105 TR to 260 TR. Model "LT" Cooling Tower: Centrifu gal fan type. . .indoor or outdoor in stallation. Capacities: 105 to 252 TR. Model "LT" Baltimore Fan Company Type "IC" Propeller Fan Wheel: Industrial ventilation (free air). 24 in. to 48 in. diameter. Baltimore Fan Company Type "LS" Propeller Fan Wheel: Medium pressure applications. 24 in. to 96 in. diameter. Baltimore Fan Company Type "HP" Propeller Fan Wheel (illus trated) : Higher pressure applications. 24 in. to 72 in. diameter. 1226; Air System Equipment Curtis Refrigerating Machine Division of Curtis Manufacturing Company 1959 Kienlen Ave., St. Louis 20, Mo., U. S. A. Established 1854 . New York Office 80 Vesby St. Chicago Office 9 S. Clinton St Full Line of Units from }4, to 40-hp Unit Coolers and Evaporator Coils 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 4ir Conditioning Installation, Packed and Remote Types. Combination air and water cooled Condensing Units. M Through S kp. \y^hpAir Cooled Condensing Unit. Other sizes from *4 to 3 hp. IS hp Cleandble Shell and Tube Condensing Unit. Other sizes from S to 40 hp. Commercial Refrigeration Air cooled condensing units from % to 3 hp, inclusive, and water cooled units from M to 40 hp, inclusive. All models available for either Freon (F-12) or Methyl Chlo ride. Mechanical advantages include Timken Bearings. Positive Pressure lu brication; [Special models are available for ice cream, frozen food cabinets and for the dairy ifldustry. and 7H Ion Packaged Type Air Conditioner. 10-16 ton Remote or Central Type Air Conditioner. Air Conditioning For today's Air Conditioning requirements Curtis offers complete packaged, refrigerated air conditioning units, re quiring only water and electrical connections to install. Cools, dehumidifies, circulates and filters the air. Eliminates costly installation expense. Adaptable for heating. . 1227 Atlakta Boston Burram COABLOTTB Chicago Cincinnati Dallas Kansas City Lob Angeles Air System Equipment Frick Company (Incorporated) Air Conditioning, Refrigerating, Ice Making and Food Freezing Equipment ' Waynesboro, Penna. urnDistributors in Principal Cities Memphis New Oblbanb New Yobk Oklahoma City Palatka PwTT.*narr-pTTTA PlTTBBTJHOH St, Louis Seattle Washinoton - NEW "ECLIPSE" Frick Compressor. Bulletin 100. 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 enable us to solve your problems. FREON-12 REFRIGERATION ' Frick NEW "ECLIPSE" and the larger F-12 compressors provide a complete and efficient line. Coils, coolers, condensers and controls to suit. Patented FlexoSeal at shaft, pressure lubrication from reversible pump, capacity controls, and other superior features make Frick machines your logical choice. See Frick Bulletin SOS on hospitals, SOS on ammo nia systems, SOI an typi cal installations, SOS on engineering details, and Sit on unit conditioners (illustrated). Eclipse Combined Unit with NEW "ECLIPSE" Compressor. Bulletin 100 AMMONIA REFRIGERATION Combined units and vertical enclosed compressors, with two or four cylinders, in sizes from tons up. Widely used for air conditioning, with material savings. Ask for Bui. 503 on this subject. Enclosed Freon-19 , Machine. Bulletin SOS. LOW-PRESSURE REFRIGERATION Commercial and industrial units in sizes from M hp up. Charged with Freon-12. Air and water-cooled condensers. Coils, coolers, and air conditioners. Get in touch with your Frick Distributor; ask for Bui. 97. Our service includes estimates, layouts, manufacture, installation, and mainte- > nance. ' Enclosed Ammonia Compressor. Bulletin lit. Air System Equipment Mario Coil Co. 6135 Manchester Ave., St. Louis 10, Mo. Manufacturers MARLO =HEArP_ _ Sine* 1995 |RAN$FER Equipment Industrial Coolers--Unit Coolers--Evaporative Condensers--Low Temperature Units-- Air Conditioning Units--Heating and Cooling Colls--Cooling Towers--Diesel Engine and Oil Evaporative Coolers. Cooling COOLING TOWERS. Triple-type; In duced Air----- Wetted. Surface----- Water Spray. Compact in space, weight and price--3 to 100 tons--Built Sectionally. Write for Bulletin 406. EVAPORATIVE CONDENSERS. 3 to 100 tons--All refrigerants--All prime sur face coils--No fins--Quiet--Motor Uni drive--Durable construction. Write for Bulletin 404- INDUSTRIAL COOLERS. Dry Coil and Brine Spray 15 unit sizes--1000 to 24,000 cfm--Floor Type. Galvanized frame and pans--Sectionally built. Variable: (1) Rows of coil and fin spacing (2) Defrost sprays optional (3) All refrigerants. Write for Bulletin 408. AIR CONDITIONING UNITS Floor and Ceiling Types. Cooling, heat ing, humidifying, dehumidifying, filter ing, circulation--1 to 150 tons--480 to 37,000 cfm. Bulletin 409. Multi-zone Unit. Complete winter and summer functions--individual zone con trol--1500 to 17,000 cfm. Bulletin 409 MZ. ELECTRIC DEFROST LT UNITS. Compact ceiling type--High capacity-- Low cost. 7 sizes--Ammonia or Freon-- J to 2\ tons at 12 deg. TD. Defrosted electrically. Quickly installed--Write for Bulletin .408. (U.S. Patent 2266373) BALL-BONDED COILS. Mechanically expanded tubes to fins--For air condi tioning, heating and industrial refrigera tion. Any material--All refrigerants. Bulletins 896 and 498. . Electric Defrost LT Units Low Pressure Refrigerating Unit, Bulletin 07. Two Frick NEW "ECLIPSE" Compressors, each with 9 Cylinders, Air Condition Weingarten's Supermarket at Houston. 1228 1229 IAir System Equipment Refrigerating Machinery Mills Industries, Incorporated 4100 Fullerton Avenue Chicago 39, Illinois Mills Compression Equipment for Air Conditioning Commercial and Industrial Refrigeration COMPRESSOR 21 in. x 3 in. four cylinder, vertical, single acting, reciprocating type . . . heavy, one piece alloyed semi-steel cylin der block and crankcase . . . oil sight glass . . . alloy semi-steel pistons, two compression rings, one oil ring . . . hard ened piston pins . . . drop forged steel connecting rods . . . bronze piston pin bearing . . . bronze main bearings ... ex clusive Mills design shaft seal. CONDENSING UNIT Base of cast iron ends and formed steel sides . . . shell and tube type receiver condenser with removable heads and leak alarm fittings . . . complete with auto matic water valve, starting box, low pres sure control with high pressure safety cut-out . . . complies with Underwriters' specifications . . . dynamically balanced and non-vibrating, light in weight, com pact, requiring a minimum of floor space. Mills Condensing Units are economical to operate and maintain. Condensing units are shipped ready to operate. No special foundations are necessary. APPLICATIONS Refrigeration in air conditioning appli cations for comfort, food preservation, and industrial uses for processing and testing. Compactness of condensing units make them ideal for self-contained ap plications. ENGINEERING Mills Industries, Incorporated main tain an engineering test laboratory as a service to their customers, equipped with three hot rooms, calorimeter, in dicating and recording, pressure and electrical instruments and all apparatus necessary for a thorough analysis of the use of condensing units to any manufac turer's product or field applications. CAPACITIES AT 40 F SUCTION GAS Size RPM C a p a c itie s in B TU D epth H eight | N e t W eight Sao S jgS oiit .SO Q .e 5 hp 480 16.37 65000 63' 29$' 32* 8951b 7}hp 700 23.86 90500 63' 29$' 32* 9451b 10 hp 890 30.34 115000 63' 30' 34' 10501b Air cooled models from K to 3 hp. Water cooled models from M to 10 hp. Combination air and water models From J4 to 3 hp. All models are designed for use with Freon-12 or Methyl Chloride refrigerants for low, standard, and high back pres sures, for operation throughout the com plete range of temperatures. ' Compressors are designed for low head temperatures and high volumetric effi ciency. . Condensers are matched to the per formance ranges of each compressor. A Member of the Mills Field Organization is Near You and at Your. Service 1230 Air System Equipment Machine'1 Boston Chicago Dallas The Ready-Power Co. 11231 Freud Ave. Detroit 14, Mich. DISTRICT OFFICES-OR REPRESENTATIVES LOCATED IN FOLLOWING CITIES Philadelphia Pittsburgh Los Angeles . Milwaukee New Orleans . New York Seattle St. Loois ' flEHDY-POlUER AIR CONDITIONING AND REFRIGERATION EQUIPMENT . Compressor Type -. Ready-Power Engine Driven Com pressor and Condensing Units are de signed and built to meet the need of (1) Low operating cost air conditioning and refrigeration employing NATURAL GAS fuel and (2) Air Conditioning and re frigeration where electric power is not available or high in cost. It is particu larly adaptable to portable equipment for pre-cooling airplanes, perishable shipments by rail or truck, and for in ` stallations in refrigerated cars and trucks. CAPACITY MODULATION The Ready-Power inherent system of capacity modulation permits operation of the compressor to meet the needs of varying conditions. This assures much better control of temperature and humidity conditions than is possible with the usual "on and off" system generally used with electrically driven equipment. On units of 15 to 55 ton the capacity modulation is controlled both by varying the engine speed and by unloading the cylinders 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. All capacity modulation is auto matically controlled. 3 TO 55 TON RANGE Unit capacities range from 3 to 55 ton for air conditioning and multiple unit installation of over 100 ton are in success ful operation. Either compressor or condensing units are adaptable for use with evaporative condenser, heat exchanger 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. All 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. 1231 Air System Equipment Refrigeration Appliances, Inc. 923 W. Lake St. Chicago 7, III. AIR CONDITIONING AND REFRIGERATION EQUIPMENT COMF-E-FEX Remote type ceiling mount comfort cooler. Available with direct expan sion or chilled water coil. Heating coil optional. Throway filter in tilting frame at air intake for easy replacement. Sizes: %, 1, 2, 3 tons. Specifically de signed for professional offices, beauty parlors, barber shops, tourist courts, and small stores--where floor space is at a premium. CLIMATE MASTER New console type air conditioner suit able for under window placement. Es- Eecially designed for office buildings, ospitals, hotels and motels, in multiple installations using water as a cooling and heating medium. Also available with direct expansion, water, or steam coils, in any combination. Provides in dividual zone control from a central sys tem while eliminating costly duct work. SAN-E-FEX Ceiling mount, central station air conditioner in six sizes from 5 to 25 tons. Avail able in direct expansion or chilled water coils. Heating coils optional. Perma nent or replaceable type filters. Expansion valve furnished with Freon model. Large, low speed centrifugal blowers. Scientifically engineered, rugged con struction. FLOOR TYPE AlR HANDLING UNIT Central station air conditioner in eight sizes from 5-40 tons. Direct expansion or chilled water coils. Heating coils option al. Permanent or replaceable filters. Expansion valve furn ished with Freon model. 12 gauge, all steel, channel formed, welded construction. Removable panels for easy access to in terior. EVAPORATIVE CONDENSER AND COOLING TOWER Floor type evaporative condensers and cooling towers in nine sizes from 5-50 tons. 12 gauge, channel formed, welded steel construction, hot dip galvanized after fabrication. Intake eliminators positively contain sump splash. De mountable sections to facilitate han dling. Turnover blower section for top, right, or left air discharge. Removable doors for easy access to interior. Sepa rate motors for pump and blower. Ceiling suspended models in smaller sizes also available. AIR-E-FEX--Custom-built air conditioning coils for water or direct expansion. We also manufacture a complete line of unit coolers and gravity coils for commer cial or industrial refrigeration and air conditioning applications. Ceiling, wall, or floor mount, for fixture or rooms, for high or low temperatures. Specification and Data Sheets upon Request 1232 Air System Equipment e//liG&UtiUM, ENGINEERING, INC. 7250 East Slauson Avenue, Los Angeles 22, California. rrcEcofl-ipg Manufacturers of Air Conditioning and Commercial Refrigeration.Equipment mm *tc. RECOLD HEAT TRANSFER EQUIPMENT gives performance with economy because each unit is designed for a specific applica tion. Whatever your problem may be--commercial or industrial refrigeration or air conditioning for cooling or heating--you will find that RECOLD equipment will meet the conditions encountered on any job. RECOLD AIR CONDITIONERS AND INDUSTRIAL REFRIGERATION UNITS Outstanding in appearance, performance and versatility, these units have pleas ing rounded corners and sparkling blue- grey hammertone finish. Totally en closed units, with large access doors to motor, expansion valves and coil connec tions. Capacities: Air Conditioners up to 50 tons; Industrial Units up to 15 tons Air Conditioning Units; Multizone Air Conditioners - Commercial and Industrial Coolers; Am monia and Freon Units 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 150 tone. Diagram Showing How "Dri-Fan" Principle Oper ates. Wasg arrows denote warm inlet air stream, other arrows show discharge of moist air. Fan is placed in dry incoming air stream, preventing rust and corrosion. -.fjnique construction provides completely sealed access doors without the use of. gaskets of any kind. Galvanized construction. /i Write for Complete Catalog and^Name of Nearest Distributor 1233 Air System Equipment Fans and blowers Aladdin Heating Corporation 2272 San Pablo Ave., Oakland 12, Calif. Manufacturers of Centrifugal Blowers, ' Heating arrd Ventilating Equipment. FC Fan BB Fan EX Fan The Aladdin FC Fan having a forward curved rotor is builtin 14 standard sizes,single or double width, of 8 arrangements of drive and 8 directions of discharge. The low tip speed which is characteristic of this fan makes it ideal for general application where quiet operation is essential. Write for Bulletin No. 490. The BB Fan is a backward curved fan with the nonoverloading horsepower characteristic. This fan is built in 12 standard sizes, single or double width of 8 arrangements of drive and 8 directions of discharge. These fans are available in class I, II, III or IV and can be built for special application where required. Write for Bulletin No. 485. The EX Fan is used chiefly for the conveying of materials, fume exhaust, etc. These fans are reversible and can be furnished in 13 standard sizes of. 8 arrangements of drive and 8 directions of discharge. They can be desirable for special applications such as for handling abrasive materials or for acid fumes. Write for Bulletin No. 460. The RB Fan having a radial curved rotor is used chiefly for kitchen exhaust duty. They are well suited for handling grease and other sticky materials, also for exhaust ing fumes and vapors from tanks, hoods, etc. This fan is built in 12 sizes, single width only, of 8 arrangements of drive and 8 directions of discharge. Write for Bulletin No. 450. The FC Utility Sets having a forward curved rotor are built in ten standard sizes, of 57 standard speed combinations, single width only. These units are self-contained and can be furnished for any rotation and discharge. All units can be furnished with weather proof hoods when required. Write for Bulletin 525. Fuseair ceiling outlets are manufactured in a complete range of sizes both in the supply type and the combination supply and return type. These units are fabricated from spun aluminum and all standard units are given an aluminum finish. Write for Bulletin No. 520. - i 'I ,| ' '. . ' -i ~ 1234 Air System Equipment *nd Blowers American Corporation 3606 Mayflower Street, Jacksonville 3, Florida Exhaust Fens and Related Eqoijment for Industrial and Home rvwijwg . Authorized Distributors and Dealers in Most Communities ' District Representatives: Atlanta, Ga.--John L. Underwood Co, Inc., 555 Whitehall St, S.W, Atlanta 3, Ga. Baltimore Mu--Herbert C. Has, 3803 Cedardale Rd, Baltimore 15, Md, phone Liberty 0781 Cincinnati, Ohio --Halsey E. Kendrick, R.R. 7, Box 89, Cincinnati 11, Ohio, Phone Humboldt 4573 Dallas, Texas--J. D. Clower, Whitewright. Texss. LD Phone. Whitewright 919F2 New York, N.Y.--E. R. Dexter, 117 N. Middletown Rd, Pearl River, N. Y, LD Phone Pearl River 5-2725 Washington, D. C.--Robert A.Msgee, 7402 Columbia Ave, College Park, Md, phone Warfield 1480. COOLAIR BELT DRIVE FANS are specifically engineered to move large volumes of air quietly and at low cost. CERTIFIED RATINGS, UL LABEL ' Coolair Fans are rated in accordance with the ASHVK Standard Test Code for Centrifugal and Axial Fans (1938). In addition, fans up to and including the 62 in. sizes are rated by the A & M Col lege of Texas and listed under the Re examination Service of Underwriters' Laboratories. SKF BALL BEARINGS in all models. Write for special bulletins and catalog sheets on above units, and the following equipment not shown here: Window Fans, Attic Packages, Shutters, Direct Drive Fans. Blade dia. (inches) CONDENSED PERFORMANCE DATA and DIMENSIONS Coolair V-Belt Drive Exhaust Fans TYPE H (Ultra-quiet, spring-mounted) hp rpm Overall Dim. (inches) Ht. Width 28 32 38 44 50 58 62 y% k, X M M H.H 490 420,475 331, 371 291, 326 284,318 242, 272 216, 241 4350 7730, 8620 9800,11050 13300,14670 17250,19300 20000, 22500 24400, 27200 30k ~30X 36H 36k 42H 42k 49 49 55X 61k 55k &> 67k 67k TYPES H and C--For commercial and home use. Type H is equipped with sound -absorbing springs, assuring exJxemely quiet operation. U. S. Patent ' 2191418. Type C is similar but with rigid frame and heavy duty blades, for com mercial and industrial use. TYPE HT (Ultra-quiet TWIN UNITS) 26 32 38 44 50 X 468 361, 420 326 317 284 8400 13000, 15460 19300 28800 34500 36H 42H 49 55K 61K 73k 85k 98 110k TYPE C (Commercial, Rigid Frame). 26 H to X 557 to 780 4900 to 7200 32 a to h 441 to 651 7300 to 10450 36k 38< yi to i 334 to 552 9100 to 14670 42k 44 X to IX 300 to 494 12040 to 19450 49 50 56 X to 3 284 to 496 17250 to 30000 55k X to 2 242 to 370 20000 to 30000 6lk 62 X to 3 1216 to 369 24400 to 41500 67k 30k 36k 42k 49 55k 61k 67k TYPE CT (Commercial Twin Unite) 26 H to H 510 to 612 8900 to 10900 30X 32 H to 38 383 to 523 12680 to 17100 334, 378 18200, 20600 mi 42X 44 'A. 1 309, 330 24800, 26500 49 50 1 to 2 284 to 351 34500 to 42600 X 61k 73k 98 110k TYPES HT and CT--These twin units often fit perfectly where limited space prevents use of a single fan big enough for the job. U. S. Patents . 2109838, 2191418. TYPE S and SX For large industrial jobs. Heavy-duty double frame con struction, pillow-block ball bearings. TYPE S (Industrial Unite) 72 |1 to 5 1155 to 270 35000 to 600001 75k ! 75k 84 |2 to 7kll?0to270 58000 to 850001 87 I 87 TYPE SX (Industrial Unite) . 96 3 to 10 150 to 225 80000 to 120000 99 99- 108 5 to 15 150 to 215 110000 to 111X Ulk 154000 1235 Air System Equipment na Biswers Bayley Blower Company 1821 S. Sixty-Sixth Street Branches in Principal emeu Milwaukee 14, Wis. Engineers and Manufacturers of Fans, Washers,. Heaters and Other Air-Handling Equipment CENTRIFUGAL FANS Bayley offers a complete selection of types, sizes and arrangements of centrif ugal fans for ventilating, conditioning and mechanical draft service, with slowspeed or power-limiting wheels. Made in single and double widths, with capac ities up to 300,000 cfm or more. Smaller sizes have reversible housings for con venience and economy. Type "F" Fans are equipped with wheels having forward-curved floats, effecting a slow-speed characteristic. The floats of the wheels supplied with Type "AP" Fans are backwardly in clined, producing a non-overloading characteristic. Choice of fans is de termined by the design conditions of the individual installation. Vent Set Type"EX" Fan Turbo Washer Chinook Heater 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 engineered and sturdily built to give long-lasting, efficient service. . 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 en countered in materials handling or exhaust. Type "H" is similar, but proportioned for relative higher pressures and smaller volumes. Designs are adaptable to spit virtually any requirement of temperature, corrosion-resistance or other severe operating conditions. AIR WASHERS--Because Turbo washers atomize by mechanical means, they cannot clog, hence are admirably suited to handling air contaminated with particulate matter. Standard pressure-nozzle washers also available for use where dust content is light. .... BLAST HEATERS--The finless, long-lasting iron pipe coils of Chinook Heaters will not dog, 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. .* 1236 Air System Equipment Fans and Blowers The Bishop & Babcock Mfg. Co. Massachusetts Blower Division -4901 Hamilton Ave. Cleveland 14, Ohio SQUIRREL CAGE AND POWER FIXED FANS Squirrel Cage Fans, outstanding in performance, slow speed characteristics. Power Fixed Fans are backward curve blade type, with non-overloading charac teristics. Double width, double inlet. Class I or Class II construction. Rating and dimension tables available. Sizes 131 in. to 861 in. wheel diameter, single and double width. Write for catalogs. MASSACHUSETTS AIR CONDITIONING UNITS Designed to combine cooling in summer and heating in _ winter. Available in seven sizes ranging from 1,000 cfm to 14,000 cfm and may be obtained in either vertical or horizontal design. These un its are built in sections to facilitate easy handling and erection. Built with vari ous heating and cooling coil combinations to suit requirements. These units in corporate traditional Massachusetts fea tures of fine workmanship and superior ' performance .^Write for catalog. The new Design 2 Air Conditioning Furnace Blowers are now available, with a wide variety of stock combinations and dis charge arrangements. They can be furnished in special widths or in multiples. Also available are wheel assemblies, housings and housing sides. Sizes 7 in. to 27 in. wheel diameter. Write for catalog. Unit Heaters. Blower type. Floor and Ceiling type made in 13 standard sizes, with regular or non-freeze coils, filter and damper sections. Ratings from 50,000 Btu up. Propeller Fan type "H," Hori zontal made in 16 sizes. Type "V" Ver tical projection for ceiling mounting. Write for catalogs for full information. Propeller Fans available with Belt drive with wheel sizes24 in. to 48 in. Direct Drive with wheel sizes 12 in. to 30 in. Both types available with single or 2 speed motor. A complete line of Automatic Shutters and Fan Houses are obtainable. Write for catalog. Air Washers. Four types available. Type A--cooling dominating cleansing. Type B--as much cooling as possible without mechanical refrigeration. Type C--cooling and cleansing with use of mechanical refrigeration only. Type D--Identical with type A except that flooding nozzles have been omitted. 1237 Air System Equipment F"s < biowot 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. For Complete Information, Write for Bulletins Indicated, or Call Your Trained "Buffalo" Engineering Representative In Nearest City Listed Below. ENGINEERING REPRESENTATIVES ALBANY 7. N. Y., Mr. R. B. Taylor, 966 Broadway; ATLANTA, QA., Mr. J. J. O'Shea, 305 Techwood Dr., N. W.; BALTIMORE l, MD., Machinery & Equipment Sales, Inc., Mr. C. A. Conklin III, 1014 Cathe dral St.; BOSTON, MASS., Mr. E. D. Johnson, 507 Main St., Melrose Station; KITCHENER, ONTARIO, CANADA, Mr. A. S. Capwell, Canadian Blower and Forge Co.; CHICAGO 3, ILL., Enunert & Trumbo., 20 N. Wacker Drive; CINCINNATI tS, OHIO, Mr. S. O. Johnson, 2944 Colerain Ave.; CLEVELAND 15, OHIO, Wearer & Sherman, 570 Hanna Bldg.; CORPUS CHRIST1, TEXAS, Langhammer-Rummel Co, 101 N. Alameda St.; DALLAS I, TEXAS/Mr. T. H. Anspacher, 615 Tower Petroleum Bldg.; DENVER, COLORADO, Hendrie A Bolthoff Co., Box 5110, Terminal Annex D: DETROIT 13, MICHIGAN, CoonDeVisser Co., 2051 W. Lafayette Blvd.; GREENVILLE, S. CAROLINA, Mr. Roy A. Stipp.P. O. Box 1796, 104 E. Stone Ave.; HOUSTON 5, TEXAS, Mr. D. M. Robinson, 2609 Sunset Boulevard; INDIANAPOLIS 4, INDIANA, 8. E. Fenstermaker & Co., 937 Architects and Builders Bldg.; DAVENPORT, IOWA, D. C. ar. u. r. oexton, r. u. sox tvs Empire Bldg.; ou r on aia.a, aajYrtjioaw.m*.,. owiunu, nal Warehouse Bldg.; LOS ANGELES 13, CAL. Halladay & Knauff, 804 Pershing Sq. Bldg.; LOUISVILLE ORLEANS It, LA., Devlin Bros., 1003 Maritime' Bldg.; NEW y6rK 7, N. F,, Johnson & Norman, 39 Cort- landt St.; NEWARK t, N. J., Johnson & Norman, Room 205,27 Washington St.: OMAHA t, NEBRASKA, "Wain"l ` Bid*.; Ing Co. m-- Apai,nNy4, 2a311nDoug"Vla.s St.;* PH. ILrAa DEP4LI*PnHIAt t,TPnA1 .,.DmamviidTslOoDnT&TBH/1uInTgMer, D12A00 Cnur.naXrTd LeeM( UAiUl 1/iJ I 1, U A Sin, race 1 urpui O. VU., IAU UU. 1UUU W., wail t u<uvv "| VOO.. O...**! " nhaa. w. Lockhart, 1214 Central Tower Bldg.; SAN ANTONIO 6, TEXAS, Langhammer Kummel Co., 300 Blum St., P. O. Box 367; SEATTLE 1. WASHINGTON, Arthur Forsyth Co., 3150 Elliott Avenue; SPO KANE, WASHINGTON, Arthur Forsyth Co., 501 Hyde Bldg.; TOLEDO 9, OHIO, Mr. Carl EyBter, 1118 Madison Ave.; WASHINGTON 6, D. C., Mr. G. S. Frankel, Mgr., 310 Woodward Bldg.; WILKES-BARRE, PA., Power Engineering Co., 517 Brooks Bldg.; TYPE "LL" FANS. Used in large ventilation systems in plants, public buildings, and shops because of their quiet operation, non-overloading characteristic and complete se lection of sizes from 600 to 500,000 cfm. Backward curved blades, inlet vanes and special housing scroll shape con tribute to high efficiencies. BULLETIN 3737. AXIAL FLOW FANS. Like the "LL" 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-C. 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 haa 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-D. 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. 1238 * Ait System Equipment % Fans and Blowers Champion Blower & Forge Co. Manufacturers and Engineers plant* offices: Lancaster, Pa. 9Address Correspondence to Div. Manufacturers of Blowers, Ventilating Fans and Exhaust Fans for Air and Material; and Blast Gates Representative* lit Principal Cities ~ Type S Forward curve ventilating fans, single and double width. Sizes 6 in. to 60 in. wheel dia. O Type 8 Type CE Electric cast iron exhaust and forced draft fans. Also volume control dampers. Type BY Type A Industrial Ventilating and domestic attic fans. Built in sizes 30 in., 36 in., 42 in., 48 in. Type SV Super Ventilating fans, direct motor drive up to 36 in. diameter. Motor belt drive up to 48 in. size. 1239 i v Air System Equipment Fans and bu>ws DeBothezat Fans Division American Machine and Metals, Inc. Main Office and Factory--East Moline, Illinois Foreign Sales Office: Woolwobth Buildino, New York 7t N. Y. SALES ENGINEERING OFFICES IN ALL PRINCIPAL CITIES LOOK IN YOUR TELEPHONE DIRECTORY UNDER "FANS" OR "VENTILATING EQUIPMENT" CONTROLLED VENTILATION FUME REMOVAL Power-Flow Roof Ventilator Motor driven fan in weatherproof hous ing provides positive controlled ventila tion at all times, regardless of wind direction or velocity. Streamlined ap pearance, low height. Operates effi ciently with or without duct system. Power-Flow Roof Ventilators are avail able with fan wheels 12 inches through 48 inches in diameter, and capacities up to 40,900 cfm. Catalog furnished on re quest. Bifitrcatcr (Cut-away view) For exhausting abnormally hot, corro sive, inflammable or explosive fumes. Motor is mounted in separate chamber. Destructive fumes are by-passed (bi furcated) around motor, as illustrated above. Bifurcator Fans install directly in the duct, in any position. Available with fan wheels 12 inches through 48 inches in diameter, and capacities up to, 45,000 cfm. Catalog furnished on re quest. - VENT SETS Vertical Discharge Roof Ventilator DeBothezat Axial-Flow Vent Sets are built with fan wheels from 16 inches through 48 inches in diameter. Fan wheels can be volume type (with 4 blades) or pressure type (with 14 blades). Non overload power characteristic. Certified performance ratings. Catalog on re quest. DeBothezat - Vertical Discharge Roof Ventilators exhaust straight up at high velocity. Available with fan wheels 36 inches, 42 inches and 48 inches in diam eter, with capacities up to 40,900 cfm. Model 7B7 has square base with conical transformation for standard curb open ings. Model 7B8 has square base with reinforcing gussets for installations re quiring special curb sizes. Bulletin fur nished on request. SPOT COOLING DeBothezat "Hy-V" Air Jets blow a directed stream of cooling air as far as 35 feet without the use of ducts. Avail able with bracket for wall mounting or equipped with portable wheeled stand. With fan wheels 18 inches through 30 inches in diameter, and capacities up to 12,000 cfm. Catalog on request. 1240 Air System Equipment Fans and Blowers General Blower Company 8600 Ferris Ave., Morton Grove, HI. , Engineering.. Manufacturing Application of Blowers Fans and Exhausters FOR BETTER AIR MOVING PERFORMANCE More than 20 years' experience in building Blowers, Fans, and Exhausters to meet the exacting specifications of leading Architects Engineers and Con tractors. Engineering skill and integrity in building, and supplying all types of Centrifugal Fans, Turbo Blowers, and Gas Boosters enables us to supply the type of equipment best suited for the particular need, whether standard or custombilt. Turbo Blower With Oil Pump Aeeembly Sales Engineering offices maintained in all large cities to bring the engineering o knowledge and skills, and the resources of General Blower Company to your organization. We engineer and build many special types of fans and blowing equipment. Consult us on your particular problems. Induetrial Pan Steel Plate Type l Write for our illusirated^Products Bulletin covering the complete line of "LUNGS FOR INDUSTRY" Direct Driven Multi-Vent Set weather cover removed Turbo Blower 1241 Centrifugal Fane- Backward and Forward Curve Types in all Standard Arrangements . / Air System Equipment Fans and Blowers Hartzell Propeller Fan Co. DIV. OF CASTLE CORP. Piqua, Ohio PROPELLER TYPE FANS Single-Propeller, Two-Propeller and Multiblade. 12in.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 48 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. . There is a Hartzell fan or blower to meet any air-moving need--Lo-Noise, Exten sion-Shaft, Pulley-Drive, Duct, Belt-Drive, Reversible, Cooling Tower and Mine Fans. Also makers of Unit Heaters, Fan-Powered Roof Ventilators, Penthouses, Intake Air Units, and Farm Crop Driers. Engineering representatives in princi pal cities. - 1242 Air System Equipment Fans and Circulators Hunter Fan and Ventilating Company Exclusive Fan Makers Sines 1886 400 S. Front Street," Memphis, Tenn. BELT-DRIVEN FANS Capacities from 5100 to 22500 cfm; sizes 24 in. to 48 in. Certified air delivery ratings. Fans tested by A & M Col lege of Texas according to Standard Test Code as adopted by ASHVE and PFMA and air deliveries are in accord ance with the standard test code for centrifugal and axial fans and conform with U. S. Department of Commerce Standard No. CS 178-51. Heavy dieformed blades, balanced for quietness. Ball bearings throughout--sealed against dirt and grease leakage. Thrust type bearings permit installation in any posi tion. Rubber-mounted ball-bearing mo tors, with built-in thermal overload pro tectors. Underwriters' Laboratory Label, with re-inspection service. Fan guaran teed five years; motor one year. PACKAGE ATTIC FANS Complete with ceiling shutter. Heavy duty motor, rubber mounted for quiet ness. Precision balanced blades. Builtin fuse link. Simple, inexpensive instal lation. Ball bearings throughout. Underwriters' Laboratory approved. Fan guaranteed 5 years; motor and shutter, 1 year. 4750 and 6800 cfm models are com plete with fan, motor and automatic ceiling shutter. Resilient rubber cush ion on fan frame forms vibrationless air seal. Shutter with integral metal trim is finished in ivory and is designed to operate quietly and to eliminate drafts when closed. 7700 and 9700 cfm models are complete with fan, motor, manual shutter, built-in switch and ceiling trim. Pull-chain located at one corner of shutter controls fan and locks shutter open when fan is operating. No acces sories are required. 18 AND 22 INCH WINDOW FANS Two speed reversible capacitor type mo tor. Cat. No. BSS00: 18 in. blade, 2500 cfm--cabinet 24 in. high, 27 in. wide ad justable to 35 in. wide. Cat. No. BS400: 22 in. blade, 3400 cfm--cabinet 27% in. high, 29% in. wide adjustable to 39 in. Certified air delivery ratings. Cat. No. W-S051. Certified air delivery: 7000 cfm. Electrically reversible. 30 in. blades. Belt-driven for quietness. Cools 4 to 6 rooms. Modern safety grille. HUNTER ENGINEERING SERVICE Hunter's Engineering Department will assist you with your cooling and ventilating design problems. See Hunter Section in Sweet's Catalog. Write for new Hunter manual "How to Cool for Comfort" giving methods and installation details. 1243 / ' Air System Equipment ^nwintdF.na 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 coBts. Rugged, heavyduty framework. Dynamically-bal anced fan wheel, direct-connected to motor. Smooth, quiet, effortless opera tion--economical, long lived. "ONENAME-PLATE" Guarantee. Certified ratings. Sizes 8 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. Cast iron base. Universal discharge. 12 ca pacities. Type "P" (right) for exhausting dust, fumes, removjd of steam, vapors. Four discharge positions to avoid friction in short bends. 7 capacities. Kitchen Ventilators and Night Cooling Fans Kitchen Ventilators (left)--wide range of sizes, types for mounting in wall, ceiling, or window. Full capacity. Extra-quiet. Rigid construction. Headlined by new LC10 Built-in Ilgette shown left above. Type "PRV" Power Roof Ventilators Night Cooling Fans (right above)--port- able model for use at attic or downstairs window. For permanent installation in attic, use ILG Self-Cooled Motor Pro- peller Fans, (top of page) . Centrifugal fan type, for exhaust from vertical flues or duct systems. Directconnected, self-cooled motor. Non overloading, backward curved wheel. 10 sizes. Up to \l/i in- SP. , 1244 . Air System Equipment tfa ctSSS Yrotes _______ Architects & Builders Building Indianapolis 4, Indiana Repheskntatives in Pbinopai* Cities Wall Exhauster Suspended Air Circulator WALL EXHAUSTERS Jenn Air wall exhauster has proven its position in the commercial and industrial ventilating field. It is a complete pack age unit designed for mounting on the wall exterior. The aluminum housing provides enclosure for the motor which is mounted out of the air stream. The centrifugal wheels are non-overloading and the air is discharged radially. In many cases such an exhauster can be installed with but a fraction of the duct work required for venting through the roof. ROOF EXHAUSTERS AXIAL AND CENTRIFUGAL TYPES These direct connected power units are available in axial as well as centrifugal types. Their low contour, special motor enclosure and all aluminum construction indicate the quality built into this prod uct. The power unit is floated on live neoprene isolators to eliminate vibration. The axial roof type is recommended for lower static pressure applications while the centrifugal units operate well against higher resistances. Both have non-over loading characteristics. AIR CIRCULATOR Jenn Air offers a positive way to over come the heat problem. This industrial air circulator is suspended from above and thereby eliminates the possibility of accidental body contact. They take up no valuable floor space and have an ad justable angle of suspension which allows their use for short or long distance pro jection. The venturi design has the effect of increasing the efficiency of the fan without sacrificing quiet operation. All of the above equipment is available in a wide range of sizes and also in explo sion proof types. Write Department H for information. 1245 Air System Equipment Fans and Blowers JOY MANUFACTURING CO. General Offices: Henry W. Oliver Building, Pittsburgh 22, Pa. MANUFACTURERS OF VANEAXIAL FANS DOTTED STATES AND TERRITORIES Wash., Spokane..............................1118 Ide Ave. Ala., Birmingham 601--10th St., N. (Crandall Eng.) Calif., Los Angeles 11............. 2900 Santa Fe Ave. Calif., San Francisco 2.................... 155 Fell St. Colo.. Denver 2 1626 Wazee St. (Schloes & Shubart) W. Va., Huntington..................... 742 Eighth Ave. IN CANADA Alberta, Calgary.................902 Ninth Ave., W. Nova Scotia, Sidney.................... 361 George St. Ontario, Galt................................ 175 Beverly St. Ontario, Kirkland Lake........24 Duncan Ave.' D. C., Washington 5...1000 Vermont Ave.. N.W. Ida., Kellogg......... .......................305 N. Elm St. III., Centbalia............................Fifth and Chestnut Tt-t.,, Chicago........................ 2315 S. Michigan Ave. Kt., Mjddlesbobo. ......................... 609 N. 19th St. Mass., Boston 15........................ 88 Brookline Ave. Mich., Detroit 21___ 15815 James Couzens Hgy. Minn., Duluth........................ 1 E. Michigan St. Mont., Butte.............................24 W. Granite St* Mo., St. Louis 10.................... 4235 Clayton Ave. N. Y., New York 7........................30 Church St. Okla., Commerce.................... Ill Commerce St. Orb 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............................117 N. Kansas St. Utah, Salt Lake City 15. .1359 S. Second West St. Wash., Seattle 4........................ 3410 First Ave. So. Ontario, Sudbuby.................... 176 Hyland Ave. Ontario, Toronto............................208 Simcoe St. Quebec, Dorval...........................Montreal Airport EXPORT OFFICES N. Y., New York 1.................Empire State Bldg. Algeria, Algiers Compagnie Joy, SA.4, Rue Charles Vallin Australia, Sydney.................... Scottish House ` Belgium, Brussels___ 15 Rue De Grand Hoepice Brazil, Rio de Janeiro C&ixa Postal, 54, Copacabana Chile, Santiago.......................................Casilla 86-D England, London WI.....................6 Carlos Place France, Paris.......................... 18 Ave. Parmentier Mexico, Mexico City......... Ramon Guzman 51-B Fb. Morocco, Casablanca Cie. (Marocaine) Joy, SA. Rue de Verdi Northern Rhodesia, N'Dola Joy-Sullivan (Africa) (Pty.) Ltd. South Africa, Johannesburg 14 Webber St., Selby AND MORE THAN 500 DISTRIBUTORS THROUGHOUT THE WORLD SERIES 1000 AXIVANE* INDUSTRIAL AND COMMERCIAL FANS Joy Series 1000 adjustable blade AXIVANE* Industrial fans are available in 124 sizes ranging in volume capacity up to 100,000 cfm with pressures up to 9.6 in. W. G. Housing diameters range from 18 in. to 60 in. For complete speci fications, construction details, and selec- tor charts giving; pressure-volume range for each fan, write for bulletin number J-605. 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 are standard equipment on all Series 1000 fans. The factory blade setting can be quickly changed to provide either a wide pressure range for any particular volume or a change in a volume simply by loosen ing a lock nut with a wrench, setting the blades uniformly with the indicator, and Blades are adjustable on the job by loosening one lock nut Cutout drawing thawing location of motor and com pact conctruction 1246 Joy Manufacturing Co. Air System Equipment f* *< Blower* 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. 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 sys tem and increases efficiency by decreas ing pressure loss. .The Joy AXIVANE* fan utilizes an aerodynamically efficient blade and sta tionary vane design. 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. 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. QUIETER OPERATION MATCHED ACCESSORIES For equal weight and space the Joy Inlet bells, screens, and fan supports AXIVANE* fan is quieter than a centrif are accessories designed to fit all AXI ugal type fan of equal volume and pres VANE* Fan housings. In ordering, it sure. The streamlined airflow from an is only necessary to state the model AXIVANE* fan makes sound insulation number with or without the accessories a simple and inexpensive operation when as desired. If required with accessories, required for the ventilation and air con these will be furnished to fit the fan ditioning of quiet spaces such as hospi model ordered without special number. tals, auditoriums, radio stations, etc., No matter how carefully a duct system where insulation against system noise is planned, an incorrectly selected inlet must be used. ben will reduce fan efficiency by increas ing intake turbulence. This excess tur MORE COMPACT Joy AXIVANE* fans are built around the motor, the fan housing becoming an actual part of the duct system. This produces a more compact design than is possible with a centrifugal fan. An AXI- 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. 1247 - Air System Equipment ISJi'wbSST"1 The Lau Blower Company 2007 Home Avenue, Dept. H, Dayton 7, Ohio Engineers and fabricators of general Air Handling Equipment Blower Assemblies* Blower Wheels Propeller Fans*Accessories NEW Series "A" Blower Assemblies The Lau Series "A'! Blower Assembly-- result of years of exhaustive tests of all Special Feaiurct Patent* Applied for types of blowers--years of research and design evolution--is the all-time, out standing achievement in the blower field. Greater mechanical strength. Greater efficiency. A more compact unit (overall size considerably smaller than formerly). Will fit more jobs. Embodies many new - and revolutionary features exclusive witfi Lau. Includes new 3-point suspension type bearing bracket--an integral part_ of the shroud--identical for various, angles of discharge. New frictionless, self-aligning bearing--completely en cased in Neoprene. New center suspen sion wheel (see below). New discharge outlet design and construction. Cut-off cannot set crooked on outlet. No wavy . edges. Faster installations. New 1-piece motor mounting easily convert ible, rear to top or vice versa, by simple use of two sheet metal screws. Many other features. Complete range of sizes. Every size tested and rated for perform NEW Series "A" Blower Wheels ance in accordance with A.S.H.V.E. and New center-suspension wheel tested and NAFM Codes. proved by us to have greater mechanical strength, truer concentricity and far more efficient performance than ordinary types of wheel. Complete details sup plied. Write Dept. H. For Further Information Propeller-type "Niteair" Fans For a wide variety of applications where it is necessary or advantageous to ex haust undesirable air and provide fresh air from the outside. Equally applic able for industrial, commercial, residen tial and farm building installations. Ef ficient and economical method for correcting innumerable air-control prob lems--removing dust-laden, foul, con taminated, or excessively hot air, fumes, gases, smoke. Venturi-type entrance housing reduces air "drag" and turbu lence--eliminates most common cause of "air noise." 5 sizes--24 in. to 48 in. These Pans Comply with . dal Standard* C8178-61 1248 Air System Equipment "whJST" Morrison Products, Inc. A 25 Year Firm East 168 Street and Waterloo Road, Cleveland 10, Ohio 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. charts, sources of component parts. One-Piece Blade Construction. ThreePiece Balanced Assembly--one-piece Housing Squares and Scroll Sides avail able for Low Cost Assemblies. blade and two pressed rings with integral Catalogs: Morrison Blower Wheels hubs welded together. --Copies Mailed Upon Request. 1249 ' ' Air System Equipment. |^^7"tnating THE NEW YORK BLOWER COMPANY SALES OFFICES 32nd STREET and SHIELDS^ AVENUE CHICAGO 16 IACTOBT, LAPORTE, INDIANA Representatives in Principal Cities FANS BLOWERS UNIT HEATERS MAKE-UP AIR UNITS HEAVY DUTY HEAT SURFACE MlB--15,000 cfm MIS--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 SOS. Type ME 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 horse-power 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 JfiS. , 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. Sieelfin Comet Exhaustair--Delivers 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 Bit. Comet 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 BIS. Type GI 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 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. General Purpose Pan Capacities 400 cfm to 18,000 cfm. Bulletin 612. 1250 Air System Equipment Fans and Blowers PROPELLAIR Div ROBBINS & MYERS, INC. 1947 Clark Boulevard SPRINGFIELD, OHIO VENTILATING SPECIALISTS IN ALL PRINCIPAL CITIES Propellair Direct- Connected Fans For Duct*, Walla, Win dows, Hoods, Roof Venti lator* 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: 800-85,000 cfm. Type "C.D." Belt-Driven Propellair Tube-Axial Type For Heat, Acids, Alka lies--Fumes, Gases, Dust For Heat, Moisture, Fumes, Dust, and Gases Propellair Extended-ShafrFans 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: 2,000 to 68,000 cfm. Tvre "CE." Propellair Sky Blast Power Roof Ventilator A complete fan unit in short duct section ready for installation in lines from 20 in. to 48 in. diameter. Type "CS" may be used for severe acid or alkaline condi tions, explosive fumes and gases. Type "CSV," for excessive temperatures, cir culates outside air through belt and fan shaft tubes to keep drive and bearings ciol. Capacities: 4,100 to 43,000 cfm. 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: 20 in. to 60 in. Capacities: 3700 to 77,000 cfm. N Airfoil-Section Blades Airfoil Principle Entrance Ring A compact, highly efficient pressure fan using standard steel drum sections incorporating standard NEMA frame motors in direct drive models. Also available in belt-driven ratings with motor outside the air stream. Cast alu minum airfoil propeller and guide vanes for maximum efficiency and durability. Available in 20, 24 and 30 in. diameters, ranging from 4,000 to 15,000 cfm. / 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. 1251 i - Air System Equipment ?"n^3WBr* The Torrington Manufacturing Co. 50 Franklin Street, Torrington, Conn. Manufacturers of Blower Wheels and Propeller Type Fan Blades. "B" ' Series AIRISTOCRAT Fan Blades--Outstandingly high efficiency is the chief characteristic of this truly new fan blade. It delivers more air for any given horsepower. 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. This high efficiency is the result of four years of research and development which from the beginning was devoted to bringing out a superior fan blade. Convincing proof of the superior per formance of this new fan may be found in the NEMA and NAFM tables prepared as a guide to selection. The catalog con taining these tables and specifications will be mailed upon request. 4-Blaie Airittocrat Attic Fan "M" Series Specifications: Three-blade models in 10 in., 12, 14, 16, 18 and 20 in. diameters; four-blade models 8 in., 10,12,14,16,18, 20,22 and 24 in. diameters. Five pitches in most sizes. Aluminum blades, steel spider and hub. Standard finishes. 4-Blade Airistocrat Attic Fan ,lB" Series AIRISTOCRAT "M" Series Attic Fan Blades--Three outstanding features of this new design are: (1) Extremely high efficiency, which gives maximum cfm per 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, in- 24, 30,36,42 and 48 in. diameters, in 40 deg pitch only. 1252 The Torrington Mfg. Co. Air System Equipment I"w "wteST" AIRISTOCRAT "B" Series Attic Fan Blades have the same proportions, proved aerodynamically correct, in all . diameters. New larger center disc and heavier spider arms increase strength and a new blade shape adds to the appearance of this carefully designed product. Available in 3, 4 or 5 blades in standard diameters 24, 30, 36, 42 and 48 in. All steel construction. Available in the following finishes: 1. Plain. 2. All one color lacquer. Pressure "U" Series--Four blade . models of steel designed for pressure , operation. Sizes 20 in., 22, 24, 26, 28 and 30 in. diameters. 4-Blade Airistocrat Pressure Fan " U" Scries "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)4, 5, 514, 6, 6)4, 8, 9, 10, 12 and 16 in. diam eters, all four blades; also 5)4, 7, 8, 9, 10 in. 6-blade. Available in the follow ing finishes: 1. Plain. 2. Lacquered. 3. Zinc plated (steel only). 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; concentric rib serving as backing for blade strip is formed at same time as h\ib socket, insuring trueness of wheel. Rigid radial ribs prevent deflection by -thrust. Three thicknesses of metal in rims make for maximum strength. Excellent for many heating and venti lating uses. Manufactured in both aluminum and steel in 1)4 in., 2,3,3%, 4, 4)4, 5,6, 7, 7)4, 8)4,9 and 10)4 in. diame ters. Clockwise or counterclockwise rota tion. Same sizes available in DA type double width, double inlet wheels.. "One Piece" Airistocrat Fan Airotor Blower Wheel--Single Width--Single Iniet Patentt $J31,06l; J7i,69S Des. ISO#4* Torrington Airotor Blower Wheel-- Double Inlet--Spider End Plates. Has blades punched and formed in a single strip, rigidly held by flanged single piece end rings. Hubs are rigidly mounted by peening. Wheels of 2)4 in., 354 in., 7)4 and 10)4 in. diameter are available at present. Additional sizes now being developed. Airotor Blower Wheel Double Inlet--Spider Bnd Plates 1253 Air System Equipment Fans and Blowers WHO Trade-Wind Motorfans, Inc, 5725 So. Main St. CLIPPER 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 8601 shows double blowers used in this 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 1601. RIGHT: Model 8601 installs in a cabinet over the stove. Inlets, equip ped with washable filters, are pro vided in base ofunit 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 Description Horizontal discharge com plete with grille. Typo Blower Single Wheel Net Air CFM 100 Recomm. Max. Room Size Cu Ft Bathrooms Only Duct Size 4' Round Motor Watts 60 1501 Clipper Interchangeable horizontal or vertical discharge, complete with grille. Two Wheels 300 1000 10*x3J' 90 2501 Clipper Interchangeable horizontal or vertical discharge complete with grille, 2-speed motor & switch. Two Wheels 425 2000 10*131' 145 3501 Super Clipper Cabinet Installation Includes housing, 2 filters, 2-speed motor and switch; stainless steel hood optional. Two Wheels 550 - 3000 13'x4' 185 1254 Air System Equipment Fans and Blowers Western Blower Company Main Office and Plant: 1800 Airport Way, Seattle 4, Washington Sales Offices in the Principal Cities West of Rocky Mountains MuUiblade Fans Mill Exhausters Exhaust Fans ' Turbine Multiblade Fans--forward curved blade, Type TR, or backward curved blade, Type "S," fans for heating, ventilating, mechanical draft, etc. Bulletins No. 30 and 31. Mill Exhausters--single or double for material conveying exhaust systems, direct connected or V-belt driven. Bulletin No. 32-3. Pulley Driven Utility Sets--V-belt driven, slow speed, quiet operating, for general utility duct ventilating systems. Bulletin No. 31. RB Volume And Pressure Fans Western Unit Heaters Pulley Driven Utility Sets 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. 53. Centrifugal Exhaust Fans Series 59--for general exhaust systems. Complete packaged units. Bulletin No. 59. Volume Heaters Spirovane Propeller Fans Air Washers--for cleaning, cooling, humidifying and dehumidifying. Bulletin No. 30. Volume Heaters--with one or more centrifugal fans for heating, ventilating and air conditioning. Available in vertical or horizontal cabinet units. Bulletin No. 54. Splrovane Propeller Fans--furnished either direct connected or V-belt driven for commercial or industrial ventilation. Bulletin No. 50. . Olympic Heat Exchangers--Converters, Side Arm Heaters, Immersion Heaters, Oil Heaters, and Condensate Coolers. Bulletins as listed above furnished upon request. 1255 Air System Equipment biowot4 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 Boston 36, Mass. CENTRIFUGAL FANS Silventvane (R) centrifugal fans are highly effective in both commercial and industrial service. Available in capacities ranging from 500 to 480,000 cfm volume --total pressures up to in. AXIFLO FANS Especially designed to operate against resistance. Either vertical or horizontal air flow. Widely used in industrial heat ing, ventilating and fume removal. VENTILATING SETS Rexvane (R) ventilating sets are direct-: connected general purpose blowers or ex hausters made in 7 sizes up to 4000 cfm. V-Belt ventilating sets are self-contained units consisting of a centrifugal fan and motor with V-belt drive. Enclosing cover available. Air deliveries from 500 to 14,000 cfm. HEAT TRANSFER SURFACE Sturtevant cooling and heating coils are available for Freon, chilled or hot water, standard steam and steam distributing . types. AIR BLENDERS For both winter and summer conditioning of individual rooms-mixes conditioned air from a central system with recircu lated air. AIR HANDLING UNITS For year-round air conditioning when connected with cooling media in summer and source of steam or hot water in winter. Units available for heating and ventilating, or for ventilating only. Available in horizontal or vertical type, with or without coil sections. Sizes from 1200 cfm to 18,000 cfm. INDUSTRIAL HEATERS Designed for large area, severe heating jobs using steam, or hot water. Capaci ties range from 77,700 to 1,270,000 Btu/ hr and 1420 to 17,600 cfm. SURFACE DEHUMIDIFIERS For central plant air conditioning, these sprayed coil units are available with chilled water or direct expansion coils. Capacities range from 5 to 115 tons of re frigeration with 1600 to 45,000 cfm. AIR WASHERS For evaporative cooling, humidifying, dehumidifying and cleaning--four types available in capacities from 4500 to 110,000 cfm. SUentvane Centrifugal Fan Design 10 Rexvane Ventilating Set Evaporator Coil Direct Expansion Type BA Surface Dehumidifier Elbow Axifto Fan Design tAB V-Belt Ventilating Set Air Waeher, Type C 1256 Air System Equipment Motors 6464 Plymouth Avenue St. Louis 14, Mo., U.S.A. Sales Offices in 32 Principal Cities 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 Wagner open-type 40 C single-speed poly phase squirrel-cage motors are built with sleeveJor ball bearings and rigid bases. rigid bases. Resilient bases are avail able on fractional hp and small integralhorsepower ratings, and face and flange type endplates can be furnished to meet specific requirements. Thermal protec Multispeed motors, vertical and flange mounted motors, and splash-proof and totally enclosed motors are also avail able. tors can be supplied on ratings through Type RP-1--Normal Torque Normal Slip IK hp. . Ratings 1/6 to 400 hp, 3 or 2 phase, all Type RA--Repulsion-Start Induction standard voltages and frequencies. I&gh starting torque, low starting cur rent. % to 15 hp, all standard voltages apd frequencies. Type RK--Capacitor-Start Induction Type RP-5--High Torque High Slip Ratings IK to 200 hp, 3 or 2 phase, all standard voltages and frequencies. . High starting torque, normal starting current. to 3 hp, all standard volt Part-Winding Increment Type Motorand-Starter Combination ages and frequencies. A low cost combination of a squirrel -cage FAN DUTY MOTORS motor wound with two parallel star cir cuits and a magnetically or manually Type TM--Shaded-pole, low starting torque, for shaft mounted propellor fans which draw air over the motor. Totally enclosed non-ventilated, no temperature operated two step increment type starter, which limits the inrush of current at starting. Available with normal or high torque open or enclosed motors. rating, with sleeve bearings, round frame or rigid or resilient base. Ratings 1/125, Write For These Bulletins 1/80, 1/40, 1/30 and 1/20 hp, 115 or 230 volts, 60 or 50 cycles. Three-speed re actor controllers can be supplied if speci MU-185--Describes and illustrates all types of Wagner motors. fied. A companion line of direct current - MU-40--Lists part numbers and prices fan-duty motors is also available. of Wagner Motor repair parts. Mst-i 1257 Air System Equipment Air vents 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 WHEN YOU CONSIDER VENTILA TORS, ASK FOR.PROOF OF PER FORMANCE . .. Ventilators are usually selected on the basis of their capacity ratings. That makes sense, but do you know that: X. Capacity ratings of most ventilators are not certified. .. 2. Capacity ratings of/most ventilators are based on horizontal wind tests only. Patent No. t!6SW HOW YOU CAN GET BETTER RESULTS WITH LESS MONEY Breidert Alr-X-Hausters provide safe, sure ventilation no matter which way the wind blows! . and . . . Breidert Air-X-Hausters pio neered with published certified capacity ratings based on tests' made with wind blowing in all directions as shown below. Only such tests can guarantee the capaci ties a ventilator will deliver under _ actual operating conditions. No matter which way the wind blows, barring in terior negative pressures, the Breidert provides safe, sure ventilation ... on roofs, vent flues, chimney tops. Station ary, no moving parts, nothing to jam or get out of order. Briedert Air-X-Hausters are ideal for Kitchen Ventilation, for Vent Flue Caps, for Chimney Tops. They also are widely used on all types of factories, commercial buildings, and residences. /\X -UJ- U * It takes fewer Breiderts to do the job as same size conventional ventilators. (or) Use the same number of smaller size Breiderts to do the same jcb as conventional ventilators. Old Method Breidert Method - Write for Free Engineering Data Book -- contains specifications and installation data, certified capacity ratings, etc. Address Dept. HV. . %By Pittsburgh Testing Laboratories 1258 ' Air System Equipment Air Vents and Roof Ventilators Hirschman-Pohle Co., Inc. 200 Lent Ave. . . . LeRoy, N. Y. Sales Representatives In Principal Cities 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. Cone removable for service switch /| for service G Spring & Rubber Vibrotion Absorbers Louver Oomper Corner ' Reinforcing and Jjt Supporting Angies 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. Standard capacity tables or suggestions to meet yonrfiequirements available on request. .- It 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 makessuch 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 pan 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): uses 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. .. . It can be furnished with any type or size of base connection desired, with or without any type of damper for any type of control. For extreme heat conditions or where injurious fumes are to be exhausted, the motor can be isolated from the path of the exhausted air by our Isolated motor section, either single or double shell. Motors used are of standard manufacture designed for vertical operation, fully enclosed, 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 for any type of application. 1259 Air System Equipment Air Intake Units Roof Ventilators Iron Lung Ventilator Company 4013 Prospect Avenue H Cleveland 3, Ohio Manufacturers of IRON LUNG Roof Ventilators and Air Intake Units Hi 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 Fans having air delivery ratings certified in accordance with the Stand ard Test Code for Axial Fans endorsed by the PFMA and the ASHVE. 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 Chaaaia, AaaamUtd" "Cvi-n-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 Approx. Net Wt. 110/220 Volt. 1 Phase. 60 Cycle 3720 x 1725 175 lbs. 5200 1725 209 lbs. 220/440 (or 550) Volt. 3 Phase. 60 Cycle 6510 H 1725 233 lbs. 8880 Vi 1725 288 lbs. 10900 l 1725 300 lbs. 13500 l 1725 390 lbs. 21150 2 1140 613 lbs. 28800 3 1140 773 lbs. 40000 3 1140 875 lbs. Approx. Shpg. Wt. 250 lbs. 316 lbs. 356 lbs. 455 lbs. 465 lbs. 565 lbs. 808 lbs. 983 lbs. 1175 lbs. 1260 Air System Equipment Air Vents and Roof Ventilators The Swartwout Company 18511 Euclid Avenue, R,`'T'Mn,aliTes in Priadpri cities Cleveland 12, Ohio DUCT EXHAUST VENTILATOR GRAVITY ROOF VENTILATORS The Airlift is a centrifugal fan unit for duct exhaust against static pressure. Operates at very low noise levels. Fan has backwardly curved blades com pletely non-overloading; streamlined in let close-coupled to duct throat increases efficiency, avoids turbulence; 14 sizes, 49 capacity variations. WEATHERPROOF LOUVERS 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 ooening per unit. Used as single units, i r 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. order in a wide selection of sizes up to 74% in. high by 48 in. wide per unit. Provide adjustable or fixed weather proof louver equipment to fit wall open ing desired. Large openings fitted with bank of units of equal size for best ap pearance. Optional operating methods; optional anchoring methods. Swartwout-Dexter Heal Valves 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, 15,18,24,30,36and 42 in. Ten foot units. Adjustable damper. Weatherproof. OTHER SWARTWOUT ROOF VENTILATOR TYPES ROTARY, yraaity AIRJECTOR, VALVENT, yjavily powered and powered JECT-O-VALVE, powered WHIRLOUT, powered See Sweets Architectural or Engineering File or send for Swartwout general catalog 1261 Air System Equipment Western Engineering & Mfg. Co. ESTABLISHED 1921 4112 Ocean Park Ave. Venice, Calif. PRODUCTS Representatives in Principal Cities HIGH EFFICIENCY ROOF VENTILATORS Air System Equipment anFSSL Air Devices, Inc. Air Diffusers Exhausters Air Filters Filter Holding Frames Hot Water Generators 17 East 42nd St. New York 17, N. Y. giThiD B"products" Agents in All Principal Cities AGITAIR DIFFUSERS Square or Rectangular in Shape Type A Western Rotary . Efficiency: Extremely high exhaust ca pacity due to "backward curved blower wheel" type mechanism. Momentum operates the Western Rotary Ventilator between wind peaks when any stationary ventilator is inoperative. Capacities certified by a foremost uni versity laboratory. (See results in our catalog.) CERTIFIED CAPACITY RATINGS (See our complete catalog) Bulk, height, weight and cost are below other types yielding comparable capa cities. Weight is important when de signing roof loading. Appearance: Modem functional design adds beauty. No guy wires needed. Guarantee: Bearings are guaranteed for ventilator life. Sizes: Available from stock in sizes 6 in. through 48 in. Forbes Syphonalre Efficiency: Exhausts high volume. Will not backdraft. Tests of a foremost uni versity laboratory show the outstanding capabilities. Openings exposed to wind will lower efficiency in a stationary venti lator. The Forbes Syphonaire has a solid 360 degree wind-band to prevent this possibility. CERTIFIED CAPACITY RATINGS (See our complete catalog in Sweet's) Bulk: Low design, light in weight. Appearance: Modern, attractive, no guy wires needed. Projects: Used for many Government projects. Sizes: Fabricated from galvanized iron. Also available in aluminum and copper or stainless steel. Sizes from 6 in. through 48 in. Westemalre Curb-Mounted Fan May be used with any ventilator of same throat size to increase exhaust volume. High speed-High velocity or Slow SpeedQUIET Operation. For fumes, smokes, dust or excessive heat. SEE OUR COMPLETE CATALOG IN SWEET'S ARCHITECTURAL FILE and ARCHITECTS AND ENGINEERS CATALOG FILE or write to above ad dress for additional catalog and list of Representatives. 1262 Type CSF Circular AGITAIRS combine beautiful design with finest operating features to give rapid temperature equalization and draftless diffusion of air. Model CSF is ___________ __ _ ...... wiu uuui u, CM U Ol|UCU C quiet, easy to install. Pressure losses at or rectangular in shape with patented minimum. Type A diffusers are smaller, built-in diffusing vanes which can be as weigh less, are easy to install. Type CM O sembled in a variety of arrangements to is for marine use. In all sizes for all divide and discharge the air in propor types of mounting and with lighting tion to the area to be served, in one--two combinations. Dampers are provided --three or four directions without the use where needed. of baffles or blank-offs. Each side delivers a quantity of air proportional to the areas served. These AGITAIRdiffusers can be The AGITAIR Diffuser Data Booh, available to architects and engineers, will help you design and install air distribution systems. Consult our engineers. installed in any location in the ceiling or sidewall and will perform efficiently, dif fuse the air quietly, draftlessly, and with '--vrapid temperature equalization through out any shaped room. AGITAIR WIND-ACTUATED EXHAUSTERS Provide proper ventilation regardless of wind direction, and with positive elimi ACOUSTICAL CEILINGS TheAGITAIR Type RTC square or rec tangular in shape is especially designed for installation in acoustical ceilings. Made in sizes to conform to standard tile dimensions. nation of down-draft. Functions at peak efficiency at average low wind ve locities. Will not restrict the flow of air or gases when there is no movement of out door air across the head. Fan-equipped units also for higher rat ings. . - 1263 Air System Equipment Air Control Products, Inc. Coopersville, Michigan ... Air Conditioning Registers, Grilles, Ceiling Diffusers and Leigh Building Products. "sd GrUles 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 side-wall or base-board 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 Regis ters. ' NO. 110 SERIES REGISTER NO. 110 SERIES REGISTERS have ver tical adjustable fins for use where verti cal air control is not needed. Single shutter type damper. Operator sets close to face yet holds damper in a position. New Adjusto-Stop permits use of damper as a balancing damper. NO. 210 REGISTERS GRILLES NO. 210 SERIES REGISTERS have ad justable horizontal fins. Horizontal fins are used 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 and baseboard design. All of the above Reg isters and Grilles are painted in beauti ful beige prime coat. . Installation frames to fit these Regis ters are available in a complete range of sizes. No. 61, 61 and 62 return air intakes are built with the same type of adjustable fins. Write for New Air Control 4 Color 52 a.c. Catalog. 1264 Air Control Products, Inc. Air System Equipment Registers And Grilles Air Diffusers 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 SIDE WALL GRAVITY REGIS TERS are styled to match with base board registers. Adaptable for side wall installation above the base board. Equipped with balanced dampers. Fins on gravity Registers can be adjusted for forced air conversion. NO. 30 FLOOR REGISTERS--Unit-Grid Construction. A strong rugged low priced Register. Face is stamped from one piece of heavy gage metal. Dial operator easily opens or closes the valve with a touch of the foot. No. 31 Return Air Face is the same Unit-Grid Construction as No. 31 Regis ters. NO. 40 FLOOR REGISTERS feature famous Rigid-Lock 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 (J^g in.) between frets. No. 41 Floor Return Air Faces are same Rigid-Lock construction as above Registers. O AIR CONTROL DIFFUSERS Built in two styles--Flush Type or S.D. stepped down type. Air flow ring de sign gives ideal air distribution. Both styles are made in seven sizes--6 in. to 22 in. A low cost unit that does the job right. INSTALLATION RINGS Installation Rings provide a firm base for fastening diffuser in place. Diffuser screws to ears on side of ring. Made in a complete range of sizes. DROP RINGS--Use where it is desirable to drop diffuser down from ceiling. 2J in. deep. Rubber gasket on top edge for tight seal. Sizes from 6 in. to 22 in. CEILING DIFFUSERS DAMPERS. A low cost easy method of regulating the air issuing from the diffuser. Use either in the end of a round pipe or with a horizontal duct. Damper operates with chain that comes through the center of the diffuser. Write for New 4 Color 52 a.c. Catalog--complete engineering data. Also infor mation on Vision-Proof Grilles. 1265 Air System Equipment Anemostat Corporation of America 10 East 39tIrStreet Representatives in New York 16, N. y. DRAFTLESS fl^UntU^-AIR 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 Aspiration 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 wall distribution are available for com fort conditioning and industrial heat ing, ventilating and air conditioning in stallations. Units are also available for high pressure systems, handling veloci ties up to 5000 fpm and 6 inches of static pressure. 1266 Anemostat Corporation of America QUALITY Anemostat Air Diffusers are scientifi cally designed according to modem 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 Over a million Anemostat Air Diffusers are now doing an excellent job in thou sands of comfort conditioning and in dustrial 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 perform ance of air outlets. The Anemotherm Air Meter, a self-contained, compact, portable instrument, facilitates the bal ancing and checking of air distribution systems by engineers and contractors. It is now commercially available and is being used with great success by engi neers and contractors throughout the country. Air System Equipment Air System Equipment a^GriUes 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 now. 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 flow. Grille to match. Airo-Flex No. 7032 Register--Grille bars set to direct air downward at 22t deg, but adjustable for other angles. Single louvre. Grille to match. 5 A--Square Lattice Grille 1268 StA--Shell Grille Air System Equipment`maoriSes Barber-Colman Company ENGINEERED AIR DISTRIBUTION OUTLETS AUTOMATIC TEMPERATURE CONTROL SYSTEMS Rockford, Illinois Completely new air distribution princi ple provides flexibility in wide range of air pattern adjustment. Units are sized to match acoustical tile and are incon spicuous in design to blend with any type of ceiling. Ruggedness and simplicity facilitate installation. DOUBLE DEFLECTION GRILLES Greater versatility from simple units is obtained by adjustable vertical fins and removable core. High aspiration efficiency, rapid diffusion, maximum temperature differential, minimum pres sure drop, and guaranteed performance. A new idea in air distribution, matching modem architectural concepts and con tinuity of design. Linear panel units can be used singly, end to end, or in patterns. Also furnished for combina tion with M21118 Day-Bright fluorescent lighting unit. renlUn-fl<5 CEILING OUTLETS Provide uniform peripheral air distribu tion with quiet operation and high diffu sion efficiency. Neat in appearance and made in several types and a full range of sizes and capacities. Adaptable to all kinds of ceiling systems. AUTOMATIC CONTROLS Automatic. Temperature Control Systems are available for all types and sizes of heating, ventilating, and air conditioning installations. These systems are composed of selected, skill fully-engineered combinations of various types of thermostats, Motor-Operated Valves, and Control Motors. Specialized Barber-Colman control units include the Micro System for non-hunting proportioning control, the Econostat for indooroutdoor zone control, a Tine of self-contained Temperature Regulators, a series of Dual Bulb Thermostats, an Adjustable Ratio Control, a Thermostatic Adjuster, and others. All units of Barber-Colman design and manufacture are ruggedly built for accurate operation, long life, maximum performance, and minimum maintenance. 1269 Registers Air System Equipment W. B. CONNOR ENGINEERING CORP. Danbury, Conn. Representatives in All Principal Cities In Canada: Douglas Engineering Co., JUd., Montreal, P. Q. KNO-DRAFT Adjustable AIR DIFFUSERS 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. Installation, balancing and inspection Type KDA for supply air. Type SRD for combination - _. . ,. mo . supply and return air. Alum,num.mzesitoS6,n. Sixes 6 to >4 in. supply neck are fast because of features like the Type HD quick-opening set-lock assembly, the neck dia. Capacities SO to <**. Capacities 50 to >,500 self-contained inner unit and the sleeve- 15JOOO cfm per unit. efm per unit, return neck area 75% of supply. type damper. System design problems are eased because Kno-Draft Diffusers are adjustable o/ler 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 ing, 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. . Kno-Dmfl Diffusersarecoveredby U.S.Patent*Nos.9,866,887;tff69,U9; trl3tJH8 and other* pending; Canadian Patents Nos. 4t9jS06; WJOS. Any angle of air discharge needed to suit ceding heights and heating, ventilating or cooling air patterns can be obtained by raising or lowering bottom Cone B. 1270 W. B. Connor Engineering Corp. Air System Equipment1 mlofafe* 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 Pig. t Self-Contained Inner Unit Fig. S 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 50 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 element of the diffuser is secured to the combined suspension and adjustment screws by a springloaded catch Equipment Pig. 4 Air Direction Adjustment Pig. 5 Balancing Pig. 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 The W. B. Connor Engineering Corp. maintains a research laboratory with a staff of trained specialists and district representatives in leading cities. Their services are at the disposal of consulting engineers, architects, air conditioning dealers and plant engineers. They can assist you in petting 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. FM. ,ryeve Haniidmbinouonk oVUn AAlilr D1/UifflUusbliUoUn It contains the latest engineering data on air diffusion and is profusely illustrated with charts, photographs, sketches and dimension prints that simplify the selection, application, location, assembly, erection, testing and adjusting of Kno-Draft Adjust able Air Diffusers. It is designed to help you get top efficiency from an air con ditioning system by creating "custom-made" air distribution patterns. For/your FREE copy, please write Dept. Y-29. See pages 1188,1189,1190 and 1191 for data on Dares Air Recatcry and Air Purification Equipment.) 1271 Air System Equipment Grults" Iv Charles Demuth & Sons, Inc. Mineola, N. Y. Demuth Draftless Air Distributors Registers, Air System Equipment Grilles, Air Diffusers Diamond Manufacturing Company Main Office & Works Wyoming, Penna. Sales Representatives in All Principal Cities DIAMOND PERFORATED-METAL GRILLES: AIR-CONDITIONING GRILLES AND REGISTERS; PERFORATED-METAL PLATES, SHEETS AND PARTS FOR ALL ARCHITECTURAL AND INDUSTRIAL REQUIREMENTS. '2 W W W W ^ rai ka k-a fi* k* ft ft fvt f-t w w w w w v w w 5V wit 9 k+j kti kti wti kti 2V* ^ r+21 W r^ !.V k*> kt .... f-t kt f.t ft fit fJ fit % if* "Jack Special" Grille Pattern, 66 per cent open area I The DEMUTH DRAFTLESS AIR DIS TRIBUTOR consists of a series of curved rmi r -1 r_-i r_-i r.i rn rji r.i r_i p_i vanes, mounted on a deflecting cone, to LJ LJ hJ LJ LJ kj kJ LJ LJ kJ No. 860 Multiple Voice Flex-Bar Air-Conditioning 1!w insure 360 deg distribution without the aid of secondary equalizing devices. A second hollow deflecting cone is arranged n n r_T m rmi r.i r.i m r_-i rji LJ kJ lVi LbJ LbJ LBJ LJ LaJ LJ LBJ r_n p_t r_T rm-i r.i rj r.i r_n r,i r.i LJ LBJ LJ LBJ LbJ LbJ l"j LBJ LBJ LbJ Register with 1-Way directional flow. Diamond Air-Conditioning Registers & Grilles are available in a wide range of at a tangent to the primary cone, forming standardized types and sizes to meet & an injection nozzle. "Greek" Grille Pattern, 68 per cent open area any probable requirement. Catalog No. i 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. Diamond Architectural Grilles have been specified by leading architects and engi neers for more than a third of a century and are now installed in many of Ameri ca's finest buildings. Superior work manship and finish in heavy-gage metal 36 illustrates many popular types and gives complete working data. It also illustrates and describes Diamond Fab ricated Grilles, Diamond All-Steel Reg isters and other modern equpment for heating, ventilating and air-conditioning. f; Type (/) assures lasting beauty--standing up U Secondary air currents, which are created through the years against rough treat by the turbulence of the discharge, air, ment which no cast-metal grille could are drawn into the diffuser by the bottom survive. More than a hundred modern or secondary cone, mixed with the supply grille designs are illustrated in our cata air, resulting in positive aspiration. log No. 36--most of which are available Lighting Fixtures as illustrated by Type SL are standard accessories and are available in Type S, Type F and Type I. in any metal and in any thickness up to 14 in. Catalog also gives complete work ing data. For pendant or other special lighting ap Type (SL) 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 . No. 168-WL Honxontal-Bar Non-Vision-Design Air-Conditioning Register of manufacture. This device is intricate in design and simple to install--two very desirable features. It adjusts the vol ume of air supplied without decreasing "Egyptian'' Grate Pattern, 70 per cent open area the efficiency of the DISTRIBUTOR. "ri X X X X X X X X X X X X X XXX3 $3 XXXXXXXXX Maltese Crore" (hale Pattern, 86 per cent open area No. 600 Round Ceiling Outlet. Available tn flee standard sizes, with or without installation frames 1272 Other Diamond Products include a complete line of Ornamental Cane and other perforated metal for Radiator Covers, Metal Furniture and scores of other archi tectural and industrial applications. Write for illustrated catalogs. 1273 Air System. Equipment andGniies 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 Eermits any sideway deflection of airow. 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 facejprovides register for shallow or horizontal ducts which will not accommodate the turning blade valve of our No. 75 Design. Multi-shutter valve (depth lf 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 2J 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. j 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. 1274 Hart & Cooley Manufacturing Co. NO. 401 DESIGN--For Perimeter Heat ing. The No 401 "Diffusaire" Sidewall Register, installed above the baseboard on outside walls, 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 be 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. Also made in Baseboard type--No. 404. NO. 410 DESIGN--For Perimeter Heat ing. No. 410 "Diffusaire" Floor Regis ter is specifically designed for perimeter heating to counteract downdrafts from windows and cold walls. Opposed louvre 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 2\ 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 80 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 Registers and Grilles NO. 210 "NO-FLEX" Floor Register. Grid-type, very sturdy with heel-proof mesh (T\ in. x l$f 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. 1275 Air System Equipment g^Ts 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, Armorgrlds, Shur-Slte 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 advantages of 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 In specifying or requesting quotations on the Hendrick dual-unit Bulator, the fol lowing information is required: 1. The name or description of the de sired ornamental grille, as given in Photograph taken with deflecting vanes lees 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 ot both. Vertical deflecting vanes, showing how the vanes map be set to produce any desired air stream pattern. Beauty + Ventilator 1276 Hendrick Manufacturing Company Air System Equipment Gru^T* 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. They are easy to install, and always lie flat because of a special flattening opera tion in their manufacture. Many exclusive Hendrick designs, orig inally produced to meet ah architect's Aroive--60 per cent Open Area specifications for some particular proj ect, are now available as standard numbers, and facilities for making spe I'^'i ii^'i i'^h cial designs to specifications make the Hendrick service even more complete. The wide range of patterns permits the li&Sil li&Sil lifxiil li&fol li&Sil li&Sil liW.il IW.il choice of a grille that will harmonize La Crosse--66 per cent Open Area with any style of architectural design or period construction. 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. Arglin--OS per cent Open Area The standard mesh can either be fur nished with grille bars permanently set v> Grilles are fabricated in heavy-gauge at the factory for straight or directional aluminum, bronze, copper, Monel, steel, air flow, or furnished so that the grille stainless steel, and other commercially bars may be individually adjusted on the rolled metals. With ample open areas job to direct air flow to any desired and accurate sizes, Hendrick grilles are degree. characterized by clean-cut perforations, fine finish, and freedom from burrs and other imperfections. M-No. --67 per cent Open Area Front View Rear View M-No. 9--67 per cent Open Area 1277 Air System Equipment gSm*" The Independent Register Co. Established 1898 3747 East 93rd Street, Cleveland 5, Ohio AIR CONDITIONING REGISTERS AND GRILLES Rear View Showing Adjustable Deflecting Vanee 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--4-way adjust able direction of air flow. Flexible verti cal grille bars, multiple valves. No. 139 Wrought Steel--Flexible hori zontal grille bars, bendable for up, down or straight air flow. Single valves. Air System Equipment Register* Grilles Register & Grille Mfg. Co. Incorporated ' 70 Berry Street, Brooklyn 11, N. Y. Headquarters for all types of Registers and Grilles RESIDENTIAL AND COMMERCIAL DOUBLE CORE REGISTERS AND GRILLES QU a Dj tIEiHEJ ' jTq ; igQ Va SB Q. C Bj DCIBBinaiBBMB|yiP7p.tn 1 " *---gWa fww-- ~-r,L b n a a o QSesj Jr b a a --**-- iwri--rrrri--im'tii fi'i in i :njei:n`i B B 0 OQEfEElJOEl'a'EBBGGSB GIT -3.0 b b a o HEioda'nn'n o a n o ' q- ; .DO ODD " o. o BO oa Ha tO_3ancOaQcsOasQstDs 'OaO*3 D a D a O0 D a O'' a! do' i IiiaaDDniDioSSaD55 b? en BUS QEJ DQDODDDQ S3 D O D 0 : Style 30--Horizontal and Vertical Adjustable Deflection Designed only for high grade work where appearance and performance are the first consideration. When used as a grille only, style 320 gives complete control of directional flow, and, when fitted with one of our many types of shutter, permits control of volume as well. Can also be had with outside adjustable bars running horizontally (Style 310). FOUR-WAY ADJUSTABLE DEFLECTION AND VOLUME CONTROL 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. RC No. 1312R--With overlapping rim 54i in. wide, on all four sides. No. 1312C--With grille core only, in stalled with moulding. 1278 Style 5i0 Grille and HMV deflecting vanes Front bars vertically adjustable, rear vanes horizontally adjustable; or Front bare horizontally adjustable, rear vanes vertically adjustable. Use No. 120 Grille for adjustable right and left deflection. Style 110 has hori- zontal adjustablelbars for up and down deflection. Ask for our catalog which shows other types of air controls; also 81 different Stamped Metal designs. 1279 ' Air System Equipment outlets and Grilles The Pyle-National Company Multi-Vent Division 1363-78 N. Kostner Ave. Chicago 51, Illinois Jw1 SI.SCE1237 ' Sales Engineers and Agents in Principal Cities of U. S. and Canada 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. Panel Frame . . . installed in the bottom of air supply duct or plenum. Control Plate . .. supporting one or more valves per panel may be easily lowered to provide ready access to duct above for cleaning. Pressure Displacement Air Valve . . . single adjusting screw raises, and lowers a valve plate above opening in control plate to regulate volume of air flow from duct into dual V shaped primary distri bution sections, the design of which insures even distribution of air over the entire perforated area below panel. 11 Outstanding Advantages 1. Radiant Panel Heating and Cooling Effect Adds to the 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. 2. Complete Absence of Strong Air Streams or Blow Eliminates All Air Direction Adjustments by Diffusing Concealed Multi- Vent Panel exposed by removal of six squares of metal acoustical ceiling. Vanes or Baffles: With Multi-Vent duct velocities are so radically reduced (with in the diffuser itself) . . . diffusion is so rapid, thorough and wide-spread ... that no air movement in excess of ASHVE comfort 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- 'This application oflow velocity, pressure displacement air diffusion is fully protected by patents. Only vnlh Multi-Vent can you enjoy its benefits. Multi-Vent is the registered trade mark of tke Pyle-National Co.. Chicago, air distribution systems and parts thereof. 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 be bisected by partitions with no possi bility of draft hazards or other unde sirable air diffusion problems. 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 1280 Air System Equipment OnUets and Grilles THE PYLE-NATIONAL COMPANY Multi-Vent Division 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 and coils. 7. No Protruding Outlets to Interfere with Style and Location of Lighting Fixtures or with Interior Ceiling Design --Multi-Vent panels are completely con 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 . . . and 2 deg is guaran teed. This insures true air conditioning comfort and will meet the most exacting air conditioning requirements for scien tific research and industrial processing. 9. More Room Air Changes Per Hour 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 * See foot note on page 1280. MULTI-VENT*--LOW VELOCITY DISTRIBUTION BY DISPLACEMENT / i titii inn i i ii uKfi mni'KiH \ \ n i r "L`"r iimimi iVi200*-3*00Fran FMd -.................... ..... m FPM 30-50 1 1FPM ) I I i I I I t I t I I I I I I OTHER DIFFUSERS--DISTRIBUTION BY HIGH VELOCITY INJECTION 1000Dud Vcbcily PPM Ps*. -- ---------- Mtdt Si. fekddfo WO CFM 700-1500\ Outlet Vcfadiy PPM 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. Panel Type MVAR-122-1 MVAR-123-2 MVAR-124-2 MVAR-125-3 MVAR-126-3 MVAR-244-1 MVAR-245-1 MVAR-246-1 MVAR-364-1 MVAR-365-1 MVAR-365-2 MVAR-366-1 MVAR-366-2 Mnwirrinm Panel Frame No. of Air CFM Sizes--Inches Valves Capacity . 12 x 24 12 z 36 12 x 48 12 x 60 12 x 72 24 x 48 24 x 60 24 x 72 36 x 48 36 x 60 36 x 60 36 x 72 36 x 72 1 75 2 150 2 150 3 225 3 225 1 300 1 300 1 300 x 300 1 300 2 600 1 300 2 600 Special sizes to accommodate lighting or ceiling decoration are available. t Allowable cfm per sq ft of panel area must be de termined by DTD and ceiling height. Write for selection data. -' Standard types with perforated ceiling plate for plaster or fibre ceiling are listed above. Panels are also supplied less perforated plate for use in metal acoustical ceilings--designated MVAMC. ' Application data will be furnished on request. 1281 Air System Equipment gSuS" 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. 41H Sidewall Register Equipped with a single damper and a 3/16 inch turned down edge for flush side wall installations. No. 331 Sidewall Register Horizontal multiple valve louvres attached to vertical "bend-ezy" faces, adjustable for four way deflection. C-F4 Perimeter Baseboard Register For use in homes, churches, and com mercial installations. Fabricated of 20 gage steel with prime coat finish only. Simplifies balancing of heating systems. * rA * * a rA s rA b rA arA isrA S!* rA fti* k^tt***************** rA * i? rA a rA H 7a iB Zk B rA * rA i3 rA * *4*4*fctt*i3*8**tt*B**ii3fc 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. Union Jack Design Plain Lattice Design All Standforated Grilles and ornamental designs are available in steel from 16 gage to i in. thicknesses. They can also be furnished in non-ferrous metals, such as alu minum, brass, bronze and stainless steel, and in varying thicknesses according to the physical properties of each metal. Complete specifications will be furnished upon request 1282 Air System Equipment oSm" Stewart Manufacturing Co., Inc. Cedar Grove, N. J. Technical and price infor mation available through representatives in all prin cipal cities, or at factory headquarters. In Canada: Douglas En gineering Co. LtcL. 101 Murray St, Montreal 3, P.Q. A complete line of registers, grilles and scoops for all types of industrial and resi dential air conditioning applications. Stewart presents 54 styles in 2140 sizes for engineer or contractor with special as well as standard specification requirements. Engineering data available, conveniently arranged for estimating large or small installations. Standard material is cold rolled steel, but stainless steel, aluminum and brass are also available for most products. Style DDH Plaster Frame Style 94 DEFLECTAIRE Style DDH, ALL-WAY SELECTIVE AIRTHROW, has two banks of individually adjustable fins--front bank horizontal, rear bank vertical. Fins are stream-lined, in. deep, spaced on % in. centers. Bank of lever- or key-operated 1 in. multiple valves can be furnished as addition or substitution. Valve blades overlap when closed and open through 110 deg arc. Overall size of face 2 in. greater than duct opening. PLASTER FRAME allows for removal of grille when desired without damage to surrounding painted areas. Usable with composition duct and becomes the base to which register is attached. Style 94, MULTIPLE VALVE WALL REGISTER, is a unit of the Stewart residential line. Horizontal face bars J4 in. center to center and in. deep, deflect air downward. Multiple valve damper is lever operating. 1 in. valves overlap when closed and open on 110 deg arc. Face bars can be bent with removable key furnished. All grilles and registers have prime coat finish and sturdy rubber gasket is cemented on registers at factory. ' DV Close The DEFLECTAIRE Line is also available with face fins on CLOSE centers. This applies to all DEFLECTAIRE products, first bank only. Spacing of fins on CLOSEtype is H in. center to center. Fins are % in. deep, streamlined, sturdy, lightweight. Lever or key-operated multiple valves available with CLOSE-Type outlets and returns. 1283 Air System Equipment GnuesTM AIR COROITIORING OUTLETS IS Titus Mfg. Corp. WATERLOO, IOWA Titus Mfg. Corp. are designers and manu facturers of Airfoil Grilles featuring the Airfoil Louver--patterned after the air foil section of an airplane. The following distinctive features identify Titus Airfoil Louvers. (1) Smooth as glass stream lined surface (2) Solid construction (3) Noiseless performance (4) Minimum turbulence. AG-25 Volume Controllers provide posi tive control of air volume. Blades indi vidually adjustable. Sponge rubber gasket holds unit firmly in duct. Titus Mfg. Corp. Air System Equipment Grnies" L-8--features horizontal front louvers, vertical rear louvers. Blades are indi vidually adjustable. Front louvers are spaced on $ in. size. 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. 270 Airfoil Grille Gives 4-way direc tional control. Louvers set on } in. cen ters. Individually adjustable to create any air pattern desired. 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. 274 Multi-Shutter Register Airfoil Lou vers are featured in front. Individually adjustable. Rear multi-shutter damperblades. 230 Return Air Grille--blades on f in. centers. Parallel to long dimension. Deep fins. Standard 1} in. beveled border. Any size grille can be furnished. RL-21 Return Air Grille The RL-21 features the blades on in. centers. They present a smooth grille surface facili tating easy cleaning. 240 Return Air Register--Features rear multi-Bhutter louvers--quick shut off. Rear blades are deep-spaced on 1 in. cen ters. 1284 HEAVY DUTY INDUSTRIAL GRILLE --features 14 gage steel blades. Vertical support bars placed on 6 in. centers. Standard grade primer coat finish. Uses 16 gage steel, extra wide border for easy mounting. Made in two sections . . . Grille Face and Volume Controller. Es pecially designed to take lower wall use and abuse. 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. AG-35 VOLUME CONTROL DAMPER ... features opposed acting blades which operate simultaneously toward or away from each other in pairs. Sets back of Grille Face--controls distribution of air to grille outlet. Furnished with key for quick, easy adjustment. RL-22--Return air grille with multi-shut ter damper blades in rear. Front blades on | in. spacing. Rear blades operated by lever on face of grille. Available with removable lever lock. 1285 Air System Equipment Gri" Engineered Products for. Residential, Com mercial and Institu tional Air Condition ing, Heating, Venti lating ' NEW BRITAIN, CONNECTICUT Tri-Flex GRILLES AND REGISTERS FOR SUPPLY Available as grilles, double deflection grilles, multi-shutter registers, double deflection multi-shutter registers . . . with individually adjustable horizontal or vertical bars. Designed to meet every requirement of supply air delivery with maximum control of air direction, throw, drop and volume. Stocked in 26 standard sizes for quick specifying and economy. Where required, non-standard sizes can be furnished. 26 STANDARD SIZES 8x 10 x 10 x 12 x 12 x 12 x 4 4 6 4 5 6 14 x 14 x 14 x 16 x 16 x 20 x 4 5 6 5 6 5 A flexible device designed for installation with Tri-Flex grilles to provide positive control of air volume . . . uniform distri bution over the entire supply outlet. Stocked in the same 26 standard sizes as listed for Tri-Flex. Also available in non standard sizes. 20 x 6 20 x 8 24 x 5 24 x 6 24 x 8 24 x 10 24 x 12 . 30 x 6 30 x 8 30 x 10 30 x 12 36 x 8 36 x 10 36 x 12 AEROVANE GRILLES AND REGISTERS FOR RETURN Aerovane grilles and registers are available with horizontal or vertical bars, styled to match the Tri-Flex line. Stocked in 20 standard sizes for quick specifying and economy. Where required, non-standara sizes can be furnished. 1286 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 24x12 24 x 18 24 x24 30x12 30x18 30x24 36 x 18 36x24 36x30 48x24 48x30 48x36 Tuttle & Bailey Air System Equipment Registers Aerofuse DIFFUSERS TYPE LISTED SIZES FEATURES FOR INSTALLATION ON CEILING 12' X 12* 16' X 16' 20* X 20' 24' X 24' 30' X 30' Delivers supply air in 360 deg. patternType DF for flush mounting in standard acoustical ceilings. . .. Type DE for in stallation on plaster ceilings. 4i' 6' 8' 10' 12' 15' 18' 21' 27' 33' 38' 15'. . .27' 18' 33' 21' 38' Flush type, extends only | in. below ceiling. Temporary deflection of air stream issuing from outer passage mini mizes streakage. Combines flush type diffuser and attrac tively styled light fixture. Six-standard sizes . . . for use with 100 to 300 watt bulbs. .. . 8' 18' 10' 21' 12' 27' 15' 33' 38' Half round diffuser for installation on ceiling where it is desirable to distribute air from a point adjacent to a side wall. FOR INSTALLATION ON CEILING OR EXPOSED DUCT 6' 15' 8' 18' 10' 22' 12' 27' 33' Manually operated auxiliary effective area control ring provides complete onthe-job adjustment of air delivery. 6' 15' 8' 18' 10' 22' 12' 27' 33' High capacity diffuser with rings offset and stepped down maximum distance. For given effective area, neck diameter is reduced to minimum. b 00 wH 8' 10' 21' 12' 27' 15' 33' 38' Combination supply and return (or ex haust) unit. Designed for installation where simplification of duct layout is essential.' FOR INSTALLATION ON EXPOSED DUCT 41 E 1 Flush type, extends only f in. be 6' low duct. Supply air is directed in hori 8" zontal plane on leaving diffuser. 10' 12' E 2 Rings graduated downward me 15' dium distance effecting an average in 18' 21' 27' crease of approximately 45 per cent in capacity over that of Type El. 33' 38' E 3 Rings stepped down maximum dis tance effecting an average increase of approximately 90 per cent in capacity over that of Type El. 1287 Air System Equipment guSST* United States Register Company General Offices: Battle Creek, Mich., U.S.A. Branches: Minneapolis, Minn., Kansas City, Mo., Albany, K. V. 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. rii:.! r: 11' ffiii il i 1111 inumimr jiiniiiiiiiimminMiijii.il .................... m'lVI'MlM1! Ilf;.j hi!ill' timiirimutiiii.ii:m,m,> i,ij . \ \ .iinm tifimnmmmimiimrtj] I i!;,f" iicmmmmimiimMiJii. 'Wr.Vrir.iiMriMfilU!)!itmniiu!11h11n11niiih) i No. 256--Multiple-Valve 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 be 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. 177WI--Vertical Valves Individually adjusted. 145VVL--Lever operated Vertical Valves. Grilles and Vents in Matching designs are available. For Complete Information Write for Catalog No. 51 or Pocket Manual No. 51. No. 153-WL Horizontal Bar Non-Vision Design-Vertical lever operated rear valves. Complete Gravity and Air Conditioning Register, as well as Fitting Catalogs furnished on request. 1288 United States Register Co. Air System Equipment GniSf18 No. 500 U.S. Celling Outlet . No. 165-3% 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. 165-3%)--without heads (0165--3%). Intakes to match No. 175-3%, 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. Ideal for perimeter jobs. No. 500 U. S. Round Ceiling Outlet. Made in 6 in.,8 in., 10 in., 12 in. and 14in. sizes. Furnished with or without No. 900 frames. However, frames are recom mended. No. 165-3% U. S. Out-of-Wall Air Conditioning Register No. 410 U. S. Perimeter Floor 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. No. 191 U. S. Multi-Flex Register No. 190 U.S. Multi-Flex Register a t' c nj oisipap a ? s r & 3C; 0 ff ''D D S f 1 ! 1a- rJ s' j qja _q___a__a___a'--w a. o -if iiL : _j -- --j--1"'~ r * P r . d i wcj o; ods;oa n 2 1 j n ij < e s' aajab b 1 `s i - o iji 5, a d mlajap u > p i, No. 190 U. S. Multi-Flex Register Stream-lined, Double-edged Grille bars. Front bank of bars--Vertical, Adjust able. Second bank of bars--Horizontal, Adjustable. Rear Valves, Horizontal Lever operated. May be furnished key operated. No. 192 U. S. Multi-Flex Register--same as No. 190--but with Vertical Bars only. 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. 1289 Air System Equipment . Air Diffusers Universal Diffuser Corp. 890 Whittier St., New York 59, N. Y. ___ Manufacturers of FLEXIFLO Adjustable Diffusers Flexiflo Fully Open Individually movable blades of equalizing deflector VARIABLE EFFECTIVE AREA The effective area of FLEXIFLO is infinitely variable; all the blades move simultaneously when the control knob is moved up or down. The air delivery can thus be varied from near zero to full output without changing the character istic air pattern, which is a flow parallel to the ceiling. Since the throw is in versely proportional to the effective . area, precise control of air flow is ob tained by simply changing the opening of the FLEXIFLO to meet your specific requirements. OPERATING PRINCIPLE It is essentially a conical spiral with flanged edges, flexibly tied together by means of a centre rod which can slide up and down. In action the FLEXIFLO simulates an infinite number of concen tric jets. The air, on leaving the blades, travels parallel to the ceiling; the low pressure area created by its temporary high speed, creates a high aspirating effect resulting in a large entrainment of room air which is rapidly mixed with the cold air from the duct. This high rate of mixture dissipates the energy of the supply air so that objectionable drafts are eliminated. Moreover this rapid mixture of cold and warm air prevents stratification and quickly equalizes the temperature. UNIFORM DISTRIBUTION Every FLEXIFLO diffuser is equipped with an equalizing deflector attached directly to the main cross bar. The bladeB are individually movable and will remain fixed in any position. Besides acting as instruments to direct the flow of air and equalize its flow, they can be used to restrict the volume in case a large reduction in neck velocity should become necessary after installation. Write for Catalog Air System Equipment . Air Flow Regulators Young Regulator Company 5209 Euclid Avenue, Cleveland 3, Ohio DAMPER REGULATORS; REMOTE CONTROLS SYSTEMS Sales Representatives in Principal Cities No. 1 No. SOI No. 60S O Young Regulators meet practically every condition where damper regulators are required for controlling air volume. No. 1--For installation on finished wall. May be locked in any position. No. 700--For remote control of one or more dampers at distances up to 250 ft. No. 704--Corner pulley eliminates fric tion where there are many turns. No. 301 and 201--For imbedding in plas ter. Cover plate flush with finished wall. No. 605 and 602--Bearing set used in place of CRS rod when regulator is mounted on side of duct. No. 656--End bearing provides a bearing for the damper rod at side away from regulator ana has a rubber gasket which Srevents air leakage. _ Fo. 401--Valcalox regulator for mounting on duct. Maybe locked in anyposition. No. 4--Adapter for connecting different sizes and shapes of damper rods to vari ous models of regulators and to adjust length of rod. No. 403--Valcalox for mounting on duct, lever adjustment. May be locked in any position. No. 910--Convector regulator for operat ing 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 suspended ceiling. No. 1015--Volume control grille gives e<pial distribution of air over entire grille and directional flow. No. 807--Register with fusible link for operation by remote control. No. 805--Damper with fusible link for operation by remote control. No. 815--Relief damper with motor and remote bulb thermostat controls tem perature of individual rooms. No. ese No. 1015 1291 No. sis Air System Equipment sheet Metals UNITED STATES STEEL AMERICAN STEEL & WIRE DIVISION. CLEVELAND COLUMBIA-GBNEVA STEEL DIVISION. SAN FRANCISCO NATIONAL TUBE DIVISION. PITTSBURGH TENNESSEE COAL A IRON DIVISION. FAIRFIELD. ALA. UNITED STATES STEEL COMPANY, PITTSBURGH UNITED STATES STEEL SUPPLY DIVISION, Warehouse Distributors, Coast-to-Coast UNITED STATES STEEL EXPORT COMPANY, NEW YORK U.S.S STAINLESS STEEL for maximum resistance to severely corrosive and high temperature conditions In chemical plants and laboratories, ductwork is put to its severest test. Here, under conditions that spell early failure for less efficient materials, fume hoods and ventilating ducts fabricated of U.S.S Stainless Steel give highly satis factory service. Even when handling the fumes of very corrosive acids, U.S.S Stainless construction pays for itself by insuring high resistance to corrosive attack. , Its greater ease of cleaning, its structural strength with minimum weight, its freedom from danger of product con tamination, and its high resistance to extremes of temperature are further money-saving advantages. U.S.S Stainless Steel is produced in a wide variety of analyses, finishes, sizes and forms to meet practically every condition of use and fabrication. Our engineers are specialists in its use and will gladly assist you in its application. Other U.S.S Steels famous for superior service U.S.S GALVANIZED STEEL--for duct work carrying humidified air and for ducts in damp locations. U.S.S GALVANIZED PAINTBOND STEEL--for ductwork requiring immedi ate painting without preliminary treat ment or weathering. Paint will not flake. U.S.S COPPER STEEL--coated or un coated, insures increased resistance to corrosion, and increases life under all Bonderized surface prevents deteriorat ing action between paint and galvanized coating. A similar sheet, U.S.S DULKOTE, is available in the South and conditions of atmospheric exposure. the West. 1292 Bends, Coils, Fittings ^5,TM*" Badger Manufacturing Company 230 Bent St., Cambridge 41, Mass, i 60 East 42nd St., New York . Representatives n principal cities Badger "PACKLESS" Corrugated Expansion Joint EXCLUSIVE all-curve corrugations equalize stresses Directed Flexing Self-Equalizing Rings on Badger Joints assure even dis tribution of stresses whether caused by temperature, pressure or movement. . . no excessive strains. INSTALLATION, OPERATING, MAINTENANCE ECONOMIES "Packless"--Made from a single tube. . . no packing ... no servicing so no man holes or tunnels are required. Flexible--Fast response to movement reduces to minimum the thrust on ad jacent equipment. Wide range of traverses--By varying the number of corrugations, traverses from a fraction of an inch up to any practical limit are possible. Wide range of pressures--Standard joints for normal pressures . . . special joints for higher pressures. Directed flexing, all-curve corrugations plus all-curve self-equalizing rings-- Exclusive features on Badger Joints pre vent stresses from localizing--assure long life, greater dependability. Rings limit and progressively control flexing movement. 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 stall. Available in copper, stainless steel and other metals--To overcome temperature, pressure and corrosion condition. 1293 Bends, Coils, Fittings Expulsion joints Flexonics Corporation - EXPANSION JOINT DIVISION (Formerly Chicago Metal Hose Corp.) Maywood, Illinois . District Offices Atlanta Boston Cincinnati Cleveland Detroit Ft. Worth Los Angeles New York Philadelphia St. Louis San Francisco In Canada: Flexonics Corporation of Canada, Ltd., Brampton, Ontario CMH CONTROLLED-FLEXING EXPANSION JOINTS For presaurea up to 300 psi--temperatures to 1600 F The control rings of CMH'-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 7$ in. may be secured with a single CMH Ex pansion Joint. Standard sizes from 3 in. to 48 in. I.D. in either stainless steel or copper. Avail able with or without stainless steel in ternal sleeves. , CMH Controlled-Flexing Expansion Joint with flanged end,. CMH Controlled-Flexing Expansion Joint with Wdd- ing End*. ' CMH FREE-FLEXING EXPANSION JOINTS For pressures up to 30 psi . . . temperatures to 1600 F CMH Free-Flexing Expansion Joints are made with single or multiple corruga tions. Designed for expansion travel up to 1 in. per unit. Additionally, misalign ment correction or offset motion is cal culated at ^ in. per corrugation when . two or more corrugations are used. 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 CMH Free-Flexing Expansion Joint with flanged Ends. CMH Free-Flexing Expansum Joint with multiple cor rugations and flanged ends. CMH Free-Flexing Expansion Joint with welding end*. CMH FLEXONIFLEX EXPANSION JOINTS For pressures to 1500 psi .. temperatures to 1600F CMH FLEXONIFLEX units make it possible to utilize, the expansion joint's advantages of compactness and simplicity of installation at pressures far beyond those which had pre viously been considered safe. While units have been designed for pressures of 5500 psi, pressures in excess of this may be handled by units of special design. 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 f-in. through the normal range of high pressure pipe sizes. 1294 Bends, Coilsr Fittings Arthur Harris & Co. 210-218 N. Aberdeen Street Chicago 7, 111. ENGINEERS AND BRONZE FOUNDERS--FABRICATORS OF NON-FERROUS METALS AND STAINLESS STEEL Metals Fabricated--Aluminum, Block Tin, Brass, Bronze, Copper, Everdur, Monel, Nickel, Inconel, Stainless Steel and EA2 SMO. Bulletin on request. nBends A We make bends in every shape from all sizes of copper tube, pipe and tubing in copper, brass, aluminum, stainless steel, monel, tin and nickel. Standard or special connections. U-bends for storage water heaters. Also special pipe work for industrial installations, plumbing, heating and brewing. Non-Ferrous Castings--"Dairywhite" nickel silver for Process' Industries Equip ment. Suitable for milk and food products machinery. Castings also of 88-10-2. 80-10-10, 85-5-5-5, silicon bronze and manganese bronze, and special mixtures. Coils For heating, cooling and condensing. All shapes made from any size pipe or tube--standard or special connections, of copper, brass, aluminum, stainless steel, KA2 SMO, monel, inconel, nickel, block tin, and Everdur. Copper Expansion Joints B'tS0 Convex B-SSO Convex B-181 Concave ^ pressure and vacuum. Made in two styles--convex and concave Sizes 4 m to 60 in. diameter. Cast iron otsteel flanges. Flanges drilled to American stand ard unless otherwise ordered: B-290 available only in sizes 4 in. to 15 in. inclusive. Metal Floats -- vyiuuiTKiw v/piiuancu ni.rn co?Per' ?Iain Steel, copper plated steel, stainless steel, KA2 SMO, alumi- Dreron^Soi pUre "ckel, Admiralty and Everdur, for open tank and all in 7 beaTMlesa copper ball floatB carried in stock in diameters of 3 in., 4 in., 5 ' ln': i1 10 ,n;> 12 m- for Pen tank and Pressures of 25, 50, 100 and 150 lb. to 19 ; fPeCi.- ?lzes and pressures--made to order. Stainless steel ball floats 2'A in. floats "lg" pressure and corrosion carried in stock--special stainless steel mSS,, to order--stainless steel ball floats larger than 12 in. diameter can be made up specially. Float catalog sent on request. 1295 Bends, Coils, Fittings sfeSS'esng Ladish Co. Cudahy, Wisconsin TO MARK PROGRESS BRANCH OFFICES New York, Buffalo, Pittsburgh, Philadelphia, Cleveland, Chicago* St. Paul, St. Louis, Atlanta, Houston, Los Angeles, Tulsa, Havana, Toronto, Mexico City Distributors throughout the U. S. and Canada Standardizing on Ladish' assures unrestricted selection in meeting your entire fit tings requirements. . .for the Ladish fittings.line is complete in types, sizes, pressure ratings and material including carbon, alloy and stainless steels, aluminum, brass and other non-ferrous alloys. WELDING FITTINGS -- Size Ranges Giren in Inches. DESCRIPTION STD. EXTRA SCH. XXWEIGHT STRONG 160* STRONG 90* Elbows 45* Elbows Long Rad. Short Rad. Reducing Long Rad. 1-36 1-30 2x1 12x6 *-36 I-36 II-30 2x1 12x6 1-36 1-12 1-12 1-8 1-8 180* Returns (Long Rad. 1 X-Long ] Rad. (Short Rad. 1-30 1-2} 1-30 4-30 1-2} 14-30 Tees [ Straight (Reducing [ Outlet *-30 |x* 30x16 4-30 5x* 30x16 4-12 *x| , 12x14 1-8 3 *-- {? lx! 30x24 ix} 30x24 1x4 12x5 lxl 8x4 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--1)o not con orm to . .PB 14-12 14-12 14-24 14-24 2-24--1)o not conJ orm to. J?JS. *-24 1-24 * 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 Threaded Blind Socket Orifice Reducing Long Welding Neck ISO# 300# 400# 4-24 4-24 4-24 4-24 4-24 1-24 1-24 4-24 4-24 *-24 4-24 4-24 1-4 1-24 i-24 4-24 4-24 4-24 4-24 4-24 1-12 i-24 1-24 4-24 i-24 600# i-24 4-24 4-24 1-24 5-24 Ml 1-12 M4 4-24 900# 1500# 2500# 4-24 4-24 4-24 4-24 4-24 4-24 4-24 4-24 4-12 4-24 4-12 4-12 4-12 1-12 |-12 1-12 1-12 i-24 1-12 F12 i-24 i-24 4-12 SCREWED & SOCKET -- Size Ranges Given in Inches DE SCRIPTION 90* Ell 45* Ell Tee Cross Street Ell Lateral Coup lings Reducer Cape Bushings Plugs Inserts SCREWED 2000# 3000# 6000# 4-4 Mi 14 Ml 14 Mi 14 4-4 Mi SOCKET WELDING 2000# 4-4 M n 3000# 4-4 4-4 4-4 4-4 4000# 14 i-4 4-4 6000# n M M 4-2 Mi 4-2 4-14 Mi 1-2 M Mi Mi 14 4 nH i-4 H 1-4 144-4 M i-4 lx}--4x1 For use with Sch. 1 40, 80 & 160 Pipe 1296 Large O.D. Flanges--26 in. through 96 in. Bends, Coils, Fittings slSdStta"* Taylor Forge & Pipe Works General Offices & Works: Chicago 90, HI. (P. O. Box 485) Plants: Carnegie Pa.; Fontana Calif.; Gary, Ind., Hamilton OnL, Can, TAYLOR FORGE WeldELLS . District Offices , New York: 50 Church Street Chicago District Sales: 208 S. LaSalle St. Philadelphia: Broad Street Station Bldg. Houston: City National Bank Bldg. Pittsburgh: First National Bank Bldg. Los Angeles: Genera) Petroleum Bldg. San Francisco: 225 Bush St. Dallas: Mercantile Securities Bldg. WddSLL 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 types, 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. ` Welding Fittings--Range of Sizes Type of Fitting Descrip tion Standard Weight Extra Strong WeldELLS 90* Long }*-30* r-30* Radius WeldELLS 90* Short l'-24' l'-24' n WeldELLS Radius 45* Long r-3o* r-3o* Radius Return 180* Long *'-30' Bends Radius Return 180* Short l'-24' l'-24' Bends . Radius Tees Full |'-24' *'-24' Branch Tees Reducing 1'xi'xr 1'Xl'X*' outlet 16*X16*X6* 24'X24'X10' Reducers Concentric rxr l'Xi' A Eccen 30*X24# 30'X24' tric Caps l'-24' l'-24' Stub Ends Lap Joints l'-24' l'-24' Saddles 2'-24' Welding 2*-24* Forged Steel Flanges--Range of Sizes Welding Neck Slip-On Lap Joint Threaded Blind Socket Type Reducing (Threaded and Slip-On) Orifice 150 300 400 600 900 1500 lb. lb. lb. lb. lb. lb. !'-24' }'-24' }'-24' *'-24' }'-24' l'-24' }'-24' *'-24' }'-24' *'-24' *'-24' *'-24' *'-24' *'-24' *'-24' *'-24' *'-24' *'-24' *'-24' *'-24' *'-24' *'-24' *'-3|' *'-24' *'-24' *'-24' *'-24' *'-24' *'-24' V-W *'-24' *'-12* *'-24' l'-24' *'-24' *'-24' *'-24' *'-24' *'-24' l'-24' IMS' I'-ia* l'-ia* l'-ia* 1297 Threaded Flange Bends, Coils, Fittings ipSuutiS"* Tube Turns, Inc. trade mark General Offices and Factory: Louisville 1, Ky. DISTRICT OFFICES: traoe mark New York, 150 Broadway...................... Rector 3*7844 Tulsa,. 420 Wright Bldg...............................Phone 2*9193 Philadelphia, Broad Street StatfonMdg.^ ^ Houston, 1709-11 Comroeree Bldg..........Charter 1668 Pittsburgh, 3001 Grant Bldg............ Atlantic 1-8848 Chicago. Suite 904,600 S. Michigan Ave. Harrison 7-8528 Angeles, 2417 E. 24th Street.. Jefferson 8257 _ __ _ ,, .. . Sam Francisco, 2811 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 ana engineering data are included in TUBE-TURN catalog and Engi-; neering Data Book No. 211, sent on request. 90* Short Radius Elbow'!. Radius Elbow 90* Long Radius El TUBE-TURN SEAMLESS WELDING FITTINGS-RANGE OF SIZES Eccentric Reducer BESCRICTIM QBtWS-ariau gadus ELBCnC-V* Shot Sadia a80B5-4S* Loot Safin fiOURJB-'UO* Looj Radin FETURRS-IStrSicrt R*fins STMBAID !ITU KKUSU man stboro 160 *'-3O' r ^'30' J'-30* *'-xr m'sr v-yr *'*r m'-ar i'-ir i'-ir i'-ir ill HOOT moo rpc sin fvi sin *' 4'24' *'ir *'-r 4'*24' *'-ir r-r 4'-24' *'ir Lap Joint Stub End Cap ggfj Saddle KTWMS-lBO'Edia loot Safin r-2vs* l'-2*' ttC-SbwW *' *'24' Vt'-VP *'-r TIE3-8etfodni Outld *'2V *'24' *'12' *'-6' ttflUttftS-Ccnantric tad Eawtric *'i H* *'i H' *'*' *' *' 24' *16' 24'US' I2*5' O'* 3*' CAPS *'-24' *'24' v-uT i'-r STUB POS-Lap Joint *'24' *'24' SWOIS r-24' lATERALS-Sntod l'-24' l'-M* lATOMLS-Bs&SBifaHUB I'-24' I'-24' CtOSSES-Sbailtt nd Redadot *'24' *'-24' BDIGS-BWfini. Grow Tm *'-24' l'-* m*-r RUCS-IWfint. Rids* Tret *'12' *'12' SU--EBVES-IdM<friantumd Fiwiiwhrri->2w4l'n**MiMHerft.iwdMl taWiJD.V-- (fe ti&mtm. TUBE-TURN F0S6ED STEEl FUNGES-RANGE OF SIZES Blind Flange Msesirnoa is* la. SOOUL 40 IB. BOB IB. BOBU. 1S0BU. tSBOU. mmxG KECK *'-24' *'24' *'-24't *'-24' *'-24'* *'24' *'12* SUMS - *'24' *'24' *'-24't *'24' W'M'* *'24' *'-ir up jonrr *'24' *'24' *'-24't *'24' *'24'* *'-24' *'12' TKBEAOEO *'24' *'24' *'-24'1 *'24' *'24'* *'1T *-12* BUKO *'24' *'-24' *'24*1 *'24' *'24'* *'24' *'12* SOCKET TYPE *'-24' *'4' *'3*' BEDUCOIG-Tbtadcd or SfeOa *'-24' *'-24' *'-24't *'24' *'-24" *'24' *'-12* Ofana-ThRatfed l'-24' 4'IT r-12' 3'-12* i'-ir CnCE-SS>0n \'-24' OOnCE-lMfat Reek l'-24' 4'-12* r-u* r-ir I'-tt* tOtaM^ra a Nxa* fan Ift'iara* * fa* 600 Ifc. 6*o*a. Ml dM * W mm, . to UOO fa. faaoi Lapped Flange "a" and "TUBE-TURH" am (rad* Hart, of Tvho Tvrns. 1ne. 1298 Reducing Outlet Tee ISO* Long radius Return Straight Lateral Wddtng Neck Flange 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 100 tons Methyl Chloride, 50 tons "Freon-12.'f Low temperature valves for --40 F to --100 F. Type iOt with pressure limiting feature TypeTK US valves in 1" , Type TCL Type TR-- Multi-Outlet ALCO SOLENOID VALVES: for all types of service. For Liquid: "Freon" --up to 75 tons. Methyl Chloride--up to 150 tons. For Suction: "Freon"--up to 8.8 tons. Methyl Chloride--up to 17 tons. For brine, water, gas, air and steam. Type Sl Type tit Type RS ALCO AMMONIA CONTROLS: Solenoid Liquid Valves^--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 M9F Type UG ALCO SUCTION LINE CONTROLS: Type B vith Strainer Type 760 "EVAPOTROL" --Pressure Regulator--H ton. uFreon-lt"--ton, Methyl Chloride ALCO ALSO MAKES: Constant Pressure Expansion Valves--Liquid and Suction Line Strainers. 1299 i ' Controls and Instruments Cam-Stat, Incorporated Division of The Paul Henry Company 11831 W. Olympic BlvA 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 XJ.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. F14-SA Model LSI-7A Specifications: Fixed cut-out and dif ferential to manufacturer's requirements. Rating--90 volt-amps at 30 volts A.C. ADJUSTABLE LIMIT CONTROL Specification: Range--80to 130F. Dif ferential--15 F. (Fixed). Rating--Jhp at 120 or 240 volts A.C. Equipped with manual summer fan switch. FAN CONTROL Model LSt^A Specifications: Range--170 to 200 F, or to manufacturer's requirements. Dif ferential-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. LSS-9A Specifications: Fixed cut-out to manu facturer's requirements. Equipped with push button to reset after cut-out. Rat ing--90 volt-amps at 30 volts A.C. Controls and Instruments Combustion Control Corporation Flame Failure Safeguards ^jrexje) For Oil and Gas Flames 77 Broadway, Cambridge 42, Mass. New York--Philadelphia--Chicago--San Francisco--Washington, D. C. District Offices in ail Principal Cities FIREYE FIRETRON FLAME FAILURE SAFEGUARD AND CONTROL FOR GAS AND OIL BURNERS--SERIES FP FIRETRON is a photo-conductive cell which "sees" all types of gas and oil flames,even relatively transparent flames. Fireye offers Systems FP-2 and FP-4, using the FIRETRON cell. System FP-2 provides operating and starting protection for automatic gas, oil, and combination fuel burners. Sys tem FP-4 provides operating and starting protection for semi-automatically and manually ignited gas, oil, and combina tion fuel burners. Since the FIRETRON scanner supervises both pilot and main flames, a single scanner provides com plete supervision. Fireye equipment is designed with com pletely fail-safe circuits, whereby com ponent failure results in immediate safety shutdown. FIREYE PHOTOELECTRIC FLAME FAILURE SAFEGUARD AND PROGRAMMING CONTROL FOR OIL BURNERS--SERIES FF Complete operating and starting pro tection for industrial and commercial oil burners with Flame Rod protection of gas pilot. Type 24PJ8 automatically starts burner and programs sequence of gas pilot, ignition, burner motor, oil valves, providing scavenging period, fuel valve delay, post ignition time. Flame Rod, Type 45JP1, monitors gas pilot flame, preventing opening of oil valve unless gaspilot is established. Scanner Type 45PH5 takes over monitoring of oil flame after pilot is established. Failure of either gas flame during ignition or main oil flame during normal operation results in immediate shutdown of burner system. Two VJPt FIREYE SMOKE INDICATORS AND DETECTORS Type 17FU1 Type 17LHS. Photoelectric Smoke Detection Systems available for indicating smoke density passing through stacks, and also for de tecting smoke in air conditioning duct systems. Photoelectric equipment for duct sys tems detects the presence of even small amounts of smoke. At the first sign of smoke, automatically turns off blowers, closes automatic louvres, and signals the maintenance department. Recom mended for theatres, stores, hotels, and other locations where smoke is a hazard to property or a possible cause of panic. 1301 Controls and Instruments Detroit Regulator Co. 1742 Rivard Street Detroit 7, Michigan LOW PRESSURE GAS REGULATORS Pacific Coast Distributor; PACIFIC SCIENTIFIC CO. San Francisco, Los Angeles, Seattle, Portland Maxitrol gas regulators feature the patented 1'Straight-ThruFlow" design principle. This construction sharply reduces pressure loss commonly encountered in conventional type gas pressure regulators. The new feature permits greater flexi bility in design of manifolds for domestic equipment, and frequently allows a reduction in pipe size of gas manifolds. Capacity charts at greater differential pressures for Industrial use at Inlet pressures up to 5 psl available on request. i i Controls and Instruments The Electric Auto-Lite Company INSTRUMENT AND GAUGE DIVISION Department HV TOLEDO 1, OHIO 1 NEW YORK CHICAGO SARNIA, ONTARIO TEMPERATURE INDICATING & RECORDING THERMOMETERS .-CAPACITY RATING (A. G. A. Listed) Model No. Pipe Sise CuFt/ Hr at 0.3 Pressure Drop 0.6 Sp. Gr. Gas RV40 RV50 RV50 RV51 RV51 RV60 RV60 RV80 RV80 RV90 RV90 RV110 RV110 H H *4 H 1 l lX W 1H 2 2V, 2H 3 146 270 270 450 460 676 705 1,250 1,260 2,030 2,030 4.200 4,900 Btu/Hr Gases 800 Btu/ CuFt or More (Natural Gas) 108,000 200,000 200,000 333,000 340.400 500,200 521,700 025,000 032,400 1,502,000 1,502,000 3,108,000 3,626,000 Btu/Hr Gases Lees Than 800 Btu/ Cu Ft (Mid. Gas) 73,000 135,000 135,000 225,000 230,000 338,000 352,500 625,000 630,000 1,015,000 1,015,000 2,100,000 2,450,000 Model No. RV40 RV50 RV50 RV51 RV51 RV60 RV60 RV80 RV80 Rveo RV90 RV110 RV110 1302 DIMENSIONS cA B D m 2H IX 3 3% 3 3H *% 3H 6X 6J4 4M m VA 4H 5% ` m 67 SK 67 m PH 7X oV4 9 V2H 9 12K m 9% 14x 14% 1H VA 2X 2* 2X 2J4 2X 2H *x 2H 3K 3H Ship- & Each H* IS IS IX* IX* VA* VA* 5* 5 BX- 9S 20 S , 200 Model 500 Recording Thermometer .Temperature cycles are permanently charted by the Auto-Lite Model 500 Re corder. Precision-engineered for accu racy, it has legible 6 in. chart. Uniformly spaced subdivisions insure accurate read ings. The movement is liquid-filled and responsive to changes throughout the temperature range. Head is compen sated for temperature changes. All recorders are enclosed in dustproof and moistureproof aluminum cast cases. Movements and all actuating parts made of nou-ferrous metals. With double braided flexible armored capillary tubing of bronze composition or A in. semi-rigid copper tubing where capillary is to be immersed in liquids. Standard chart ranges between minus 40F and plus 550%. Choice of 24-hour or 7-day mechanical chart rotation. Complete with 100 charts, bottle of recorder ink, ink dropper. Wide choice of temperature ranges. Model 500 is made in 3 standard types: WALL MOUNTING, with brackets for mounting; bottom connection. PORT ABLE with spool-wound capillary, and strap handle. PORTABLE, SELF CONTAINED, with strap handle. Model F-l Indicating Thermometer This thermometer is designed to facili tate systematic temperature observation for air conditioning, refrigeration or heating applications. It has large, easily read dial, evenly calibrated and fully compensated for temperature changes at the indicating head. Choice'of tempera ture ranges between minus 40F to plus 750F. :. Equipped with flexible capillary tubing for distance reading, or with rigid stem for direct mounting. Auto-Lite's perfected one-to-one liquid filled movement eliminates delicate parts. Due to its strong construction, these instruments are particularly suited for installation on equipment where vi bration is a factor. Available with adjustable, electric alarm contact at small added cost. Auto-Lite Indicating Thermometer, Model F-l, may be mounted in 3 posi tions by simple screw adjustment. Send for Illustrated Catalog describing styles and types of Auto-Lite Thermometers, In- eluding detailed information on dial and chart ranges available, ' Controls and Instruments Fulton Sylphon Division ROBERTSHAW-FULTON CONTROLS CO. Knoxville 4, Tenn. Sales Representatives In Principal Cities Manufacturers of Sylphon Automatic Temperature Controlling Instruments and Packless Expansion Joints HOT WATER SUPPLY ordinary radiator valves with these Syl No. 999 phon Automatic Valves--no wiring, pip ing or auxiliary equipment is required. Temperature Regulator con trols temperature of liquids. Particularly suited for stor age water heaters and for all industrial processes re quiring accurate tempera ture control. Stainless steel frame for 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-80. minimum heat conduction. Large size Sylphon Bellows provides added power. Self-operating. Valve sizes from in. Sylphon No. 890 Radiator Control Valve to 4 in. Temperature ranges start at 40 F., up to 420 F. Bulletin HVG-A. For either exposed or concealed radia tion. Similar in appearance and action No. 902 Sylphon Thermostatic Water to other Sylphon Automatic Valves, but Mixers operated by an electric wall thermostat. The closing of the thermostat circuit energizes a low voltage electric heater coil surrounding a bulk 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 desired, offers effective zone control of large areas at a fraction of the cost of conven tional motor-operated valve systems. Bulletin HVG-80. Utilize hot water from any storage tank or instantaneous heater, and effectively regulate the amount of cold water re Sylphon No. 7 quired to temper it to the desired degree, Temperature Control actually mixing the hot and cold water together before delivery. Temperature remains constant in spite of fluctuations in supply water temperatures or pres sures. Four sizes with capacities rang ing from 5 to 131 gpm. Bulletin HVG-A A self-contained, self-powered regulator for controlling unit heaters, wall or ceil ing type radiators, heating coils in ducttype heating systems, etc. Quickly in SPACE HEATING CONTROL stalled, holds temperatures within close limits. Valve placed in steam line to , r : ; No. 885 Automatic Radiator Valve-- one or a battery of heaters, thermostat mounted on wall or column. For use on regular heating pressures up to 15 lb. For exposed radiation. Small, neat, at tractively finished, adjustable to room temperature desired. Simply replace Similar regulators, Nos. 7-2 and 7-3 for 50 and 75 lb. Pressure and temperatures up to 170 F. Bulletin HVG-50. 1304 Fulton Sylphon Div. Controls and Instruments REFRIGERATION CONTROLS No. 945-Z Regulator eliminates service problem and makes this regulator ideal for installation in in accessible locations. Suitable for steam pressures up to 15 lb; other types availa ble for pressures up to 75 lb. 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-A. The No. 928-ECC Sylphon Regulator if PACKLESS EXPANSION VALVES No. 110-M Sylphon Expansion Joint The Sylphon Packless Expansion Joint eliminates useless building height, ex pensive construction, non-revenue pro ducing space. No leaks or repairs, no ; repacking, always tight; heating sys- ` tern operates at full efficiency. Bulletin HVG-65. 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- 1 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 lator offer compensating control, auto matically raising their low limit setting at a predetermined rate as outside tem peratures fall. Sensitive--Close operating tempera ture differentials. 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 ranged to control any air conditioning system and to provide exactly the condi tions desired. Write for Bulletin SAC-850 The No. 928-C Regulator Room control and low-limit control in a single valve regulator for modulating control of ventilating systems. Main control from an electric room thermostat operating through the electric head "D" on the valve. Low-limit control by Bulb "B" located in discharge duct from the heater. Bulb "C", located in inlet side of the duct to the heater, compensates Bulb "B." Compensating thermostat can be furnished to raise low-limit setting at predetermined rate with falling out side temperature. Suitable for steam pressures up to 15 lb. The Sylphon No. 889-C Regulator A modulating, dual-function regulator for control of duct heating and ventilat ing Bystems--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 lb. The Sylphon No. 889-C7 Regulator 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. Fackless valve 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. 1305 I > Controls and Instruments GENERAL M CONTROLS 801 ALLEN AVENUE GLENDALE 1, CALIF. MaHufejctusieSiA of Automatic Pn&Uube, *lemp&uUuacf Jleoei tyloia QoutnoU. FACTORY BRANCHES: Baltimore 5, Birmingham 3, Boston 16, Buffalo 3, Chicago 5, Cleveland 15, Columbus 15, Dallas 2, Denver 4, Detroit 21, El Paso, Glendale 1, Houston 6, Indianapolis 4, Kansas City 2, Milwaukee 3, Minneapolis 2, Newark 6, New Orleans, New York 17, Omaha 2, Philadelphia 23, Pittsburgh 22, Salt Lake City 4, St. Louis 3, San Francisco 7, Seattle 1, Tulsa 6, Washington 6. l).C. DISTRIBUTORS IN PRINCIPAL CITIES. (A) Type T-70 <B) Type K-10 (A) THERMOSTATS Compact, snap-action, T-70 Thermostat. Functional beauty for accurate, remote control of desired temperature. Extends only % in. from wall. Streamlined stain less cover, sensitive to slightest tempera ture change, ivory plastic base. (B) MAGNETIC 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. LP.S., port sizes up to J4 in. (D) SLOW OPENING GAS VALVES New combustion control afforded by these diaphragm-controlled gas valves. Governor regulates fuel supply to burner in direct ratio to steam pressure, elim inating hunting aspect. Available 1 in. to 6 in. I.P.S. (E) MAGNETIC GAS VALVES Versatile, two-wire, straight magnetic current-failure valve. Packless. In sures tight shut-off indefinitely. Hum less. Size range, % in. to 6 in. I.P.S. Operating pressures up to 10 lb'. Volt ages and frequencies a.c. or d.c. Quiet, positive, troublefree. Available in ex plosion-proof housing. (C) BX-69 GAS ACTUATED PACKAGE SETS (F) Type V-110 (F) MANUAL RESET VALVES No outside current required. Operates Equipped with manually-reset electroon all types of gases. Safe, quiet, de magnetically-held valve operator. Cur pendable. For all gas-heating appli ances. Set consists of a PG-9 600 milli volt pilot generator, a B-60 gas control valve, a T-70 snap-action thermostat, rent flowing to operator permits manual opening by turning valve wheel at side. Current failure releases operator allow ing valve to close. Trip-free mechanism thermostatic cable and vent tubing. cannot be opened under unsafe condi Everything needed in convenient pack tions. Once closed, valve must be re age for remote gas control. opened manually. 1306 General Controls Controls and Instruments (G) Type G-l-7 (H) Type K-ll (G) HYDROMOTOR VALVES 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 piloted, two-wire current fail ure, high pressure, packless. Handle large capacities with minimum pressure drop and loss. Tight shut-off. Oper ates on air, steam, water, and refriger ants. (I) *hl-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 ahything 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. (K) GAS FUEL GOVERNORS Throttle gas lines according to boiler ressure applied to diaphragm. Ball earing thrust adjustment, ground and polished non-corrosive steins, low fric tion packing gland seal, multiple cali brated springs, high lift for maximum capacity. Suitable for butane, natural or manufactured gas. Available in. to 3 in., I.P.S. (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 Model) Manually-reset, electromagneticallyheld-open valve with current generated by single couple subject to heat of pilot flame. Available J4 in. to 134 in. I.P.S. m Type LSI, (O) Type V-S00 (I) Type RS-100 (J) RELAYS AND TRANSFORMERS Type RS-100 handles single phase motor loads up to 1 hp or heating loads up to 1.1 lew. Combines double-break relay and integral transformer. Normally open; large double-break contacts. Twowire control circuit; maximum holding current 0.4 amps. Furnished with 34 in. conduit connections and low voltage outlet, a.c. only. (N) FAN AND LIMIT CONTROL Combination. Fan and Safety Limit Control incorporates two separate switch units, one acting as a fan control; the other for safety limit operation. Each switch makes and breaks its own cir cuit independently. External adjusting knob on fan switch may be turned to "fan summer" position for manual con trol of fan for summer ventilation. (O) LOW PRESSURE GAS REGULA TORS New V-300 Series are reliable, troublefree valves with high capacity, close regulation, yet small and compact. Reg ulator size range from 34 to 6 in. I.P.S. Internal parts, corrosion-resistant. * Trade-murk--"hi-g" Indicates positive ability to function in any position, regardless of vibration, change 01 motion or acceleration. 1307 Controls and Instruments Field Control Division of H. D. Conkey & Company, Mendota, 111. Mami/acfurers 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. 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 C/ 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 SCOTTY-W: For hot water heaters. 6 in. Tee for 6 in. outlets. 26 gauge steel throughout. Pre-set at . factory to manufacturer's specifications. Ly 2 in. diameter lighting opening with cover on Tee. Collar, from heater to tee, 3| in. Tee length, 11 in. Control Tee to collar, 3 in. A precision made Field Control. 1308 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. Approved under safety codes. DIAPHRAGM TYPE--For low-pres sure refrigerants. 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 offj 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" S.A.E.; Y" thru i%" O.D. solder; K" thru 1" 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- laced while valves are under pressure. tock sizes Y" thru Ys" S.A.E. and solder. TYPE 705--Has two inches more dehy drant capacity than established prac tice. Brass shell, forged brass end caps with integral fittings. Dehydrant ca pacity 8 to 32 cu in. Sizes, M" thru Y" flare. TYPES 748, 756 and 757 cartridge driers with side outlet, dispersion tube, safety cylinder, cartridge retaining spring and distortion-proof access flange. Dehy drant capacity 12 to 500 cu in. Sizes Ys" thru 2ys" O.D. solder. STRAINERS ` WING CAP PACKED VALVES Bronze with solder connections in globe and angle types, Ye thru bYs" O.D.; semi steel with F.P.T. connections in globe and angle types, sizes Y" thru 2"; semi steel with bolted bonnets and square companion flanges with brass tailpieces for O.D.S., \Ys thru bYs . Also avail able with steel tailpieces for welding to pipe IY2" to 8" I.P.S. inclusive. TYPES 891 and 892. Screen area 11 and 25.5 sq in. respectively. Sizes Ys thru %" flare and Ys" thru Ys" O.D. solder. TYPE 895 steel "Y" strainer, forged brass end caps. Distortion-proof access flange. Screen area 23 to 150 sq in. Sizes Ys" thru 4Ys" O.D. solder; 1' to 3* FPT. RELIEF VALVES FERROUS TYPE-For ammonia. Sold by refrigeration jobbers. Write for Free Catalog. 1309 Controls and Instruments Hubbell Corporation P. 0. Box 700, Hawley Road Mundelein, 111. Designers and Manufacturers of Automatic Control Valves For All Refrigerants Controls and Instruments Illinois Testing Laboratories, Inc. Room 516,420 N. La Salle St., Chicago 10, 111. Precision Instruments for Every Industry Typt DSA-9, 8FD-9 Type SA-5, SA-6, SF-5 and SF-6 Back Pressure Regulating Valves are of the con ventional type used to maintain a constant evaporator pressure. Type SA-7, SA-8, SF-7 and SF-8 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. The DSA-9 and DSF-9 is a dual regulator which will control evaporators with two load conditions requiring different refrigerant temperatures. The diaphragms in the dual head may be set for any two evaporator pressures and will automatically change from one to the other by the opening or closing of the electric pilot valve. The SAC-6 and SFC-6 valves are of the compensating type and are used where a con stant temperature is desired in the medium being cooled. These valves will increase or decrease the evaporator pressure to compensate for the increase or decrease of the cooling load. Operated with air or electricity. The Type "T" suction stop valve is used where automatic suction line control is required. It is operated by high pressure gas and its construction makes a tight closing valve and its dependability far surpasses the conventional magnetic stop valve. All valves have built-in opening stems, which eliminates the by-passes usually used for manual operation. With either screwed, welding type flanges or copper tube connections, in sizes from % in. to 8 in. inclusive. Solenoid Valves from % in. to 2 in. inclusive for liquids and gases with composition seat discs readily renewable, coils for any electrical characteristics, built-in lifting stem standard, with either screwed, welding flanges or copper tube connections. Strainers in all sizes for liquid and gas with very large screen areas and arranged to bolt directly to valve or with screwed, welding flange or copper tube connections for installation wherever strainer is necessary. Write for complete information on these and our many additional Refrigeration Con trols and Accessories. 1310 The Alnor Velometer is an instan taneous, direct-reading air velocity meter designed for convenient, rapid determination of air velocities in air conditioning, heating and ventilating, and exhaust systems. It gives instan taneous direct readings in feet per min ute, without timing, calculations, or reference to tables or charts. Accurate information on performance of equip ment, duct systems, etc., can be ob tained with a few moments inspection with the VELOMETER. 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, 1-Jin. deep. Weight, 8oz. Accu rate, strong. Available in single and double scale ranges: 0-200 to 0-2500 fpm. Bulletin 725 The Alnor Velometer is built in sev eral standard ranges from 20 fpm to Alnor Thermo-Anemometer. For accu rate measurement of low air velocity. 6000 fpm, and up to 3 in. static or total Compact, direct-reading, battery oper pressure. Special ranges available as ated, self-contained, portable. Scale 6 in. low as 10 fpm and up to 25,000 fpm velocity and 20 in. pressure. Meter ranges: 0-600 fpm and double range 0-300/100-2000fpm. Accurate readings as lowas5fpm. Temporary Bulletin913-A. 1311 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. or Canada, Ltd,, 3615 Danfobth Ave., Tobonto 13, Ont. Halivax, N. S. Montreal, Que. 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 installation men available at all branches listed above. None is an agent, 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. 1312 Single Room Thermostat T-400 "Dual" Room Thermostat T-+60 Room Humidostat H-107 Piston Valve tor Convectors . V't60 Johnson Service Company Controls and Instruments Rigid Steam Insertion Thermostat T-808 . Sub-Master Capillary Thermostat TSOI V-10S Globe Valve with Pilot Positioner Sub-Master 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. V; JOHNSON HUMIDITY CONTROL' V, - ; 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, by-wood strip, bow-wood, horn, hair 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 gases and liquids. Johnson "Streamline" Diaphragm Valves--With modulating discs and special internal construction. Superior 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 posi tioner, independent of friction and pressure variations. JOHNSON DAMPER 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. "Masonite" is standard. Ebony, asbes tos, steel, polished oak, and genuine or imitation marble on order. Various apparatus is mounted on special switch boards, including gradual, lever type and multiple-step switches, clocks, air pres sure gauges, recording gauges, etc. S-Way Mixing Valve) (Rubber Diaphragm V-103 Piston Damper Operator D-Z51 Proportioning Louver Damper D~tt6 1313 Controls and Instruments The Mercoid Corporation i Main Office and Factory, 4201 Belmont Atenue, Chicago 41, Illinois New York Office, 205 East 42nd St. Philadelphia Office, 8137 N. Beoad St. AUTOMATIC CONTROLS FOR HEATING* AIR-CONDITIONING, REFRIGERATION AND VARIOUS INDUSTRIAL APPLICATIONS MERCURY SWITCHES BY MERCOID V /\ /\\ A`(rtti*ll* jpflt Tilting Type There are three primary operating types of Mercoid Mercury Switches:--1. MAG Magnetic Type NETIC TYPE, applied in a sSttaattiioonary Light Actuated Type position. Circuit is opened or closed with magnetic attraction by means of a per manent magnet or a small milli-ampere electromagnet. 2. TILTING TYPE, a variety of sizes, electrical capacities and arrangements available. 3. LIGHT ACTUATED TYPE. These switches are immune to dust, dirt or corrosion. THE 100% MERCURY SWITCH EQUIPPED CONTROLS No. I No. I No. i No. I No. 1. Pressure Controls Noted for their accuracy and depend able performance. The outside double adj ustment feature and visible dial eliminate all guesswork when setting the operating range. Various ranges and circuits available. No. 8 No. 2. Low Voltage Thermostats Mercoid Sensatherms operate on a total differential of 1 degree F.- Type H is the popular room thermostat. Type DNH is a hand wound day and night thermostat. Type HBH is a two-stage thermostat for control of high-low gas or oil burners. No. 3. Temperature Controls Available with or without remote connection for use with liquids or gases such as air, oil, water or distillate vapors. Equipped with a Bourdon tube and outside double adjustments. No. 4. Lever Arm And Float Controls The lever arm type is used where it is desired to mechanically open and close electric circuits. The float type is used to main tain fluid levels in tanks, or for control of sump pumps, etc. No. S. Line Voltage Thermostats No. 855 thermostats will directly handle the full motor load without the use of a relay. Available with "on-off" manual switch for unit heater applications. No. 6. Low Water Controls Available as a combination pressure and low water con trol or as a low water control only. May be furnished with quick-hook up fittings designed in accordance with the ASME code. - No. 7. Transformer-Relays Type V is a reliable low voltage mercury contact relay which also acts as a transformer inducing low voltage (24 volts) on the pilot circuit. Available in various voltages, cycles and circuits. No. 8. Vlsaflame Control For domestic and industrial oil burners. from the light of the flame instead of from the heat in the stack. into the burner unit. 1314 Operates direct It may be built . Controls and Instruments Milwaukee Gas Specialty Company 730 North Jackson St., Milwaukee 2, Wisconsin BASO* THERMOELECTRIC SAFETY PILOTS . Straight through valves with one pilot tapping each side. Cast, heat treated aluminum alloy bodies with replaceable electromagnetic hood assemblies and reset assemblies. 100 per cent shutoff safe lighting. A 8H Model A814-1 A814-2 A814-3 A505-1 A506-1 Inlet W F.P.T. W F.P.T. VS F.P.T. F.P.T. \ys F.P.T. Outlet W F.P.T. F.P.T. X" F.P.T. 1' F.P.T. 1 F.P.T. Pilot Tap ping H* F.P.T. W F.P.T. F.P.T. X* F.P.T. W F.P.T. Capacity Btu/hr. 80,000 101,000 130,000 280,000 329,000 Thermo couple Type 88D 88D 88 D 58D 58D Straight through low height valves with built in plug cock for main burner and pilot burner control. 100 per cent shut off and safe lighting. With or without pilot adjustment on either side. Model 841 has special plug head for single rod control of floor furnaces. Uses 88D thermocouple lead. Model 840-1 841-1 A842 Inlet F.P.T. Y? F.P.T. X* F.P.T. Outlet W F.P.T. W F.P.T. X" F.P.T. Pilot Tapping w c.c. H' C.C. Ye" C.C. Capacity 85,000 85,000 165,000 830 Switch Electrical Rating: .3 Amps at 250 A.C. .06 Amps at 230 Volts D.C. Uses 88D thermocouple lead Switch Type Baso is wired in series with automatic gas valve and other controls. Opens circuit to main valve in case of pilot failure. Main burner cannot be lighted until pilot is operating and switch held in closed position. 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 A814 or A505. Available in many current types. Two pilot tappings. Series C Basoid in % in. size only. . Model B4411 B4511 B4451-B1 B4551-B1 C4411 Inlet X0 F.P.T. \" F.P.T. X" F.P.T. Is F.P.T. X* F.P.T. Outlet Pilot Tap ping Current Type Capacity X* F.P.T. 1* F.P.T. Xm F.P.T. 1' F.P.T. X* F.P.T. W F.P.T. M' F.P.T. Hm F.P.T. F.P.T. W F.P.T. 115V, AC 115V, AC 20V, AC 20V. AC 115V, AC 159,000 189,000 159,000 189,000 94,000 Couple Lead Type 58D 58D 58D 58D 88D Basoid Reg. U. S. Pat. Off. 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-300-3. 1315 Controls and Instruments MINNEAPOLIS-HONEYWELL REGULATOR CO. 2644 Fourth Ave., S., Minneapolis 8, Minn. Cable Address: Minnreo, Minneapolis HONEYWELL CONTROLS for Heating, Ventilating, and Air Conditioning BROWN INSTRUMENTS for Indicating, Recordings and Controlling APPLIANCE CONTROLS for pas. Water and Space Heaters MICRO SWITCHES for all applications ' BELFIELD VALVES for Industrial applications -Factories: Minneapolis, Minn..Philadelphia, Pa_Wabash, Ind., Fbeeport, III., Chicago, III., Los Angeles, Calif., Toronto, Canada ' Broach Offices or Distributors are located in the following cities: Albany, N Y. Albuquerque, N.M. . Amarillo, Tex. Anchorage, Ai.abka Atlanta, Ga. Augusta, Georgia Baltimore, Md. Binghamton, N. Y. Birmingham, Ala. Boise, Idaho Boston, Mass. Buffalo, N. Y. Charleston, W. Va. Charlotte, N. C. Chicago, III. Cincinnati, Ohio Cleveland, Ohio Columbub, Ohio Corpus Christi, Tex. Dallas, Tex. Davenport, Iowa Dayton, Ohio Denver, Colo. Des Moines, Iowa Detroit, Mich. Duluth, Minn. East Orange, N. J. El Paso, Tex. Fargo, N. Dae. Fort Wayne, Ind. Fort Worth, Tex. (Aero only) Fresno, Calif. Grand Rapids, Mich. Great Falls, Mont. Greenville, S. C. Hartford, Conn. Houston, Tex. Indianapolis, Ind. Jacksonville, Fla. Kansas Cut, Mo. Knoxville, Tenn. Los Angeles, Calif. Louisville, Kt. Lubbock, Tex. Madison, Wis. Memphis, Tenn. Menasha, Wis. Milwaukee, Wis. Minneapolis, Minn. Nashville, Tenn. New Haven, Conn. New Orleans, La. New York, N. Y. Norfolk, Va. Oklahoma City, Okla. Omaha, Neb. Peoria, III. Philadelphia, Pa. Phoenix, Abi2. Pittsburgh, Pa. Portland, Me. Portland, Ore. Providence, R. 1. Richmond, Va. Roanoke. Va. Rochester, N. Y. Sacramento, Calif. Saginaw, Mich. St. Louis, Mo. Salt Lake City Utah San Antonio, Tex. San Francisco, Calif. Seattle, Wash. Shreveport, La. Sioux City, Iowa South Bend, Ind. Spokane, Wash. Springfield, III. Springfield, Mass. Syracube, N. Y. Toledo, Ohio Tulsa, Okla. Washington, D. C. Wichita, Kans. Wilmington, Del. Worcester, Mass. Youngstown, Ohio In Canada: Calgary, Edmonton, Hamilton, London, Montreal, In Puerto Rico: Santurcb In Mexico: Guada lajara, Mexico City, Monterey In Europe: London Brubsels, Stockholm, Amsterdam, Zurich Toronto, Vancouver, 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 in stallation. In addition, the Brown Instrument Division of Honeywell manufactures a specialized 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 eliminates the possibility of service difficulties and misunderstandings that often result from split responsibility when controls are purchased from more than one 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 install 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 mark "Modutrol" is used to designate Honeywell electric control systems designed for air conditioning or heating applications (other than domestic). It is your guarantee of Honeywell quality. A wide variety of both modulating and two-position motors, controllers and valves provide a flexible selection of Modutrol Valve control equipment. ELECTRONIC CONTROL Now, because of the many special features of Honeywell Elec tronic Control, it is easy to achieve results which previously would have been extremely difficult or impossible. Electronic controls are super-sensitive and accurate. They are simple in operation and very flexible in application. Honeywell electronic thermostats have no moving parts. A single one can be used to control heating, ventilating and cooling. The control settings can be maintained constantly or may be reset automatically. An almost unlimited number of averaging and compensating controls can be used to obtain practically Electronic Thermostat any desired result. 1316 Minneapolis-Honeywell Regulator Co. Controls and Instruments PNEUMATIC CONTROL The "Gradutrol 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 Gradutrol Relay, a Honeywell develop ment, which eliminates friction loss and allows accurate graduation of valves and damper motors, make the Gradutrol System a truly remarkable advance in pneumatic control. Pneumatic Radiator Valve COMBINATION SYSTEMS The outstanding advantages of the Honeywell pneumatic Gradutrol 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 Electric-Pneumatic Relay 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. Recording Thermometer FREE HONEYWELL LITERATURE Listed are but a few of the many pieces will be given prompt, personal attention of literature available, giving full infor --whether you contact the main office in mation on various Honeywell control Minneapolis, or any of the Honeywell devices and systems. Any inquiries you subsidiaries or branch offices located in may have pertaining to Honeywell equip principal cities throughout the United ment or some specific control problem States, Canada, and other countries. Zone Control with Inside Thermostats Residential Zone Control Specifications Unit Heater Control Automatic Controls for the Modem School Plan Your Hospital's Atmosphere Zone Control and Individual Room Con trol--For Homes Pneumatic Radiator Valves Spring-Return Valves Electronic Moduflow for Radiant Panel Heating Electronic Combustion Control Electronic Air Conditioning Control Electronic Humidity Control Modem Methods of Apartment Heating and Heating Control Weatherstat Zone Control Honeywell Aquatrol System for Com mercial Heating Automatic Controls for Heating and Air Conditioning Brown Industrial Instruments Send yonr request for literature to Minneapolis-Honeywell, Minneapolis 8, Minnesota, or to your nearest branch office. 1317 Controls and Instruments Moeller Instrument Company 132nd St. and 89th Ave., Richmond Hill 18, New York Representatives in Principal Cities INSTRUMENTS FOR HEATING AND VENTILATING 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 4J in., 6 in. and 81 in. sizes with flexible extension tubing. Scale ranges from minus 40 to plus 1000 F or its equivalent in centigrade. 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, 41 in. diameter dial, scale ranges frofn 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 made in ranges from minus 150 to plus 1125 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 1318 Controls and Instruments Penn Controls, Inc. Main Office--Goshen, Indiana; In Canada--Penn Controls, Ltd. Offices and Representatives Atlanta; Bebkely; Chicago; Cleveland; Dallas; Datton; Denveb; Detroit; Los Angeles; Minne apolis; Milwaukee; Moline; Newton, Mass.; New York; Philadelphia; Pittsburgh; Rochester; Salt Lake City; St. Louis; Seattle; Export--13E.40rHSr., New York 16, New York . . Distributors and Jobbers In All Principal Cities Automatic Controls for Heating, Refrigeration, Air Conditioning, Engines, Pumps and Air Compressors . 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 new line of Liquid Expansion Fan and Limit Controls)--Vapor and Steam Pressure Controls -- Relays and Relay-Trans formers--Humidistats--Day-Nite TemClocks--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. Stoker Timers Series S70 Low Side Pressure Control REFRIGERATION CONTROLS A complete line of automatic commercial refrigeration controls ... in a wide choice of pressure and temperature models to fit every need. Series 270 Heavy Duty Refrigeration Control fea tures two-pole, load-carrying contact structure and direct-reading calibrated scales. Other controls in the refrigeration line include: Cooling Room Thermostats -- Humidistats -- Relays -- Solenoid Valves--Line Starters and Motor Con tactors in Size 0, 1, and 1}--and Water Regulating Valves in sizes up to 2J in. I.P.T. Write for free catalogs which give complete descriptions and specifica tions. 1319 Series t7l\Dual Pressure Control Motor Starters and Contactors Water Regulators / '> Controls and Instruments Milwaukee 7, Wis. .Perfex Controls Ltd., Toronto 1, Ont. REPRESENTATIVES IN--Boston, Buffalo, Chicago, Cleveland, Indianapolis, Milwaukee, New York, Philadelphia, San Francisco. . DISTRIBUTORS IN--Atlanta; Baltimore; Bangor, Me.; Boston; Butte; Cedab Rapids; Chicago Cincinnati; Cleveland; Denver; Des Moines; Detroit; Fort Watne; Grand Rapids; Greensboro; Hartford; Indianapolis; Kansas City; Knoxville; Los Angeles; Louisville; Milwaukee; Minne apolis; Nashville: New Orleans; New York; Omaha; Philadelphia; Pittsburgh; Portland, Ore gon; Providence; Richmond; Rochester, N. Y.; Salt Lake City; San Francisco; Seattle; St. Louis; St. Paul; Sioux Falls; Syracube. 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 Gage Hot Water Controls Draft Control Draft Gage AUTOMATIC HEATING 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 control? (for gas, oil, stoker or. hand firing) time switches, relays, and barometric draft regulators. Feature of Perfex controls is the "Twin Conv' tact"; Switch--which gives double action, positive contact, - ipagnetic snap-action, immunity to vibration, doesn't require leveling and has no flexible leads to impede action or impair calibration. Line Voltage Thermostats Stoker Primary Controls OH Burner Primary Controls 1320 Solenoid Gae Valves > Controls and Instruments The Powers Regulator Co. 60 Years of Temperature and Humidity Control--Offices in over SO Cities General Oifice and Factory: Skokie, I1L New York 17, N. Y, 231 East 46th St-- Chicago 13, 3819 N. Ashland Ave.--Los Anoeles 5, 1808 W. 8th St.--Boston 15, 125 St. Botolph St.--Detroit 1, 320 McKerchsy .V----. [QJ | l 3,2118 Pine St.--New Orleans 12, 208-209 Vincent Bldg.--Kansas City 8, 1610 Main St--Seattle 1, 3160 Elliot Are.--Atlanta I 3, 142 Spring St. N.W.--Dallas 1. 2415 N. J Pearl St.--Greknheoro, 733 Jefferson Stand- Bldg.--Philadelphia 32,2240 N. Broad St. YMUard Bldg--Toronto, Ont., 195 Spading --Cleveland 3, 1670 E. 40th St.--Sr. Lome Ave.--Mexico, D.F. Apartado 63 Bis. A very complete line of Temperature, Humidity, Pressure--indicating, con trolling, and recording regulators--for heating and air conditioning systems, industrial processes and all types of hot water heaters. Sixty years of experience in furnishing and installing temperature and humidity control for every conceivable purpose in all types of buildings have given us a wealth of experience from which you can draw in selecting the proper type of control for any purpose. Catalogs and Bulletins describing our products fur nished upon request. Phone or write our nearest office. See your phone directory. 1321 i I Controls and Instruments Rochester Manufacturing Co., Inc. DfPfNtUBU ACCURACY 80 Rockwood St, Rochester 10, N. Y. 274 Madison Are., NEW YORK 16 - 9443 S. Ashland Are.. CHICAGO 20 2949 Harriet Are., S,, MINNEAPOLIS 1355 Market SU SAN FRANCISCO 3 1011 Green- mount Are.,'BALTIMORE 2 - 6270 Souder SL. PHILADELPHIA 24 - 4 Manor Rd., East, TORONTO, ONTARIO, CANADA. ,, Rochester Gauges--Dependable Accuracy Liquid level, pressure and temperature gauges in a wide range of types CIRCULATION AIR CONTROL THERMOMETER KIT 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 tinie. 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. LEAK-PROOF, PRESSURE-TIGHT 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 basement tank depths--22, 24, 27, 42, 44 or 47 in. Model S17S PRESSURE AND VACUUM GAUGES Designed for indicating and testing. Pressure gauges, 0-200 lb-vacuum 0-30 in., 2 in. dial, J 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. 1322 Maid ttSO 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 ft 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. 1323 2_j- Controls and Instruments Spence Engineering Company, Inc. 28 Grant Street, Walden, N. Y. 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 trouble-free, heatingduty. 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 _R_e,,g_u_l_a_t_or _re_d__u_c_e_s the steam pressure in addition to accurately modulating the ^ flow as required to control the temperature. No separate reucing valve is necessary. By adding a SPENCE Solenoid Pilot any SPENCE Regula tor may be cut on and off electrically. 4- The Spence design provides a self-op erated , pilot controlled regulator entirely packless in construction and guaranteed to shut tight. SECO Metal seats and discs will not be cut by the wire-drawing action of steam. Spence thermal ele ments 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. 1324 Controls and Instruments Sterling, Inc. 3738 North Holton Street Milwaukee 12, Wisconsin Heating and Temperature Control Products Distributed through leading Heating and Plumbing Wholesalers Sales Representathes in Principal Cities HEATING SPECIALTIES Thermostatic Traps: sizes 'A in., M in- 1 in.; max. pressure 15, 65, 100, 125 psi; Angle, Straightway, Corner, Vertical Body Styles. Float and Thermostatic Traps: sizes % in. to 2 in.; max. pressures 15, 100 psi. Strainers: max. pressure 125 psi; Cast Iron Sizes A in- to 2 in.; Brass Sizes % in. to 1 in. Also Radiator Valves, Boiler Return Traps. Illustrated at right is the compact, sturdy % in. 69B F & T Trap, which like all other Sterlco traps has a bellows type thermostat and replaceable seats and valve members. 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 14,000 sq ft EDR, 20 psi. 3500 Series: heavy duty units with ped estal 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. TEMPERATURE CONTROL VALVES No. 120 Thermotrol (illustrated): self-contained individual radiator temperature control for steam or hot water. Easily installed in place of manual radiator valve without wiring or other external connections. Tank Temperature Controls: self-powered modulating control valves for fluid heaters and process equipment. Sizes:% in., A in., in., 1 in., m in., \A in., 2 in. 1325 Controls and Instruments *iaulor In&trAimavt CjomtuuwA f Rochester 1, N. Y., U. S. A.-., ' IN CANADA--Tatbob Instbument Companies op Canada Ltd., Tobonto NEW YORK CHICAGO BOSTON PHILADELPHIA BUFFALO LOS ANGELES ST. LOUIS CINCINNATI PITTSBURGH SAN FRANCISCO TULSA CLEVELAND HOUSTON . BALTIMORE Manufacturing Subsidiary in Great Britain, Short A Mason, Ltd. London ATLANTA MINNEAPOLIS WILMINGTON SCHENECTADY SCOTIA Taylor Instruments for Indicating, Recording and Controlling Temperature,. Pressure, Humidity, Flow and Liquid Level (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 atented triple-lens construction, its road mercury column can be read easily and accurately with both eyes. Bore reflection is absent. (B) Taylor Biram'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) Taylor 10BG Hygrometers For air conditioning supply and return ducts, dryers, and other closed compartments where temperature and humidity read ings are desired. Combines the accuracy of an etched-stem thermometer and rug ged ness of an industrial thermometer. Available with bottle or constant auto matic water supply. (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. (E) 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 "P" Controllers; Indi cating Hygrometers and many types of Humidiguides. Controls and Instruments WALKER ' fojfrrnatic. DRAFT REGULATORS Walker Mfg. & Sales Corp. Sales Office & Factory 1701-10 Penn St. St. Joseph, Missouri Type 34 B These - controls - for Space and Water Heaters, Floor and Utility Furnaces, Ranges and Stoves. Ring and Damper pressed from steel; fittings are brass. Larger sizes are interchangeable for economy with Domestic Controls. These controls feature the Walker patd., non-clogging, closed box hinge. SIZES, SMOKE PIPE with Tee Joint with Collar Damper Section only 3' 4' 5' 6* 7' 8' HP' X X X X X __ __ __ X XXXXXX X XX X XXX X X Standard Finishes x denotes availability These controls made , in selected sizes are similar to Type 34B except that ad justment feature and balance assembly Type34C are refined to provide ease of setting and proper draft control. Prices are slightly higher, but these controls are extensively used by manufacturers who demand the best. SIZES. SMOKE PIPE 4' 8' with Tee Joint with Collar Damper Section only Standard Finishes Blued Blued Cad. or Zinc Iridite Type 34 DOMESTIC CONTROLS These controls are for central heating lants in homes, Apt. Bldgs., Churches, tores, Schools, etc. for economy and peak performance. All materials are carefully selected for resistance to heat, corrosion, moisture and soot. Aluminum ring assures positively rigid construc tion. Aluminized steel features the Damper Plate construction. Pivot pins are cadmium plated; adjustment and balance assemblies are brass. EE PIPE 6' 7' 8' 9* 10" 12* 14' 16' with Collar x|X|XjX X X X x|x|X Damper Section only X 1 * 1 X 1 * X X X X | X 1 X Standard Finishes Cast Aluminum Frame or Ring Brass Fitl TYPE BB--Industrial--These controls are ruggedly constructed for industrial boilers. Pivots are ball bearing. Close grained cast iron used in frame for rigid, proper alignment. Cast iron and brass fittings, in conjunction with tempera ture-resistant finish, assure longlife. No installation collars furnished. For de tails of installation or other recommen dations, write for further information. SIZES, Equiv. to Rd. Pipe Draft Regulator only StapdaVd Finishes 16' 18' 20* 22* 24' 26' 30r 36' Ix|xlx||x|x|z| ALL SIZES--Cast Iron Frame and Painted Steel Damper Plate or Vane 1327 Boilers Heating Systems Radiators . Convectors American ,, ^tandavd Radiator ^c^anitapg CORPORATION P. 0. BOX 1226, PITTSBURGH 30, PENHA. American Radiator & Standard Sanitary Corp. Heating Systems &,nSi4era 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--960 to 25,600 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 480 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. Ratines: Steam--930 to 4600 sq ft, Water--1640 to 7360 sq ft, installed radiation. 1328 1. WESTMORELAND WINTER AIR CONDITIONER For oil. Steel unit expertly engineered for automatic oil fired heating, with or without Arcoflame Oil Burner. Five sizes, from 150,000 to 330,000 Btu capacity at register. 2. WYANDOTTE WINTER AIR CONDITIONER For gas. Steel utility type unit for small homes with or without base ments. Factory assembled, pre-wired, cleanable heating ele ment. Five sizes, with A.G.A. input ratings from 55,000 to 125,000 Btu. Side or bottom return air inlet. 3. MAYFAIR SUMMER AIR CONDITIONER For summer cooling. The Mayfair summer air conditioner, latest addi tion to the American-Standard line, converts forced warm air heating system to year 'round conditioning. It uses same duct system. . .mechanically cools and dehumidifies the air. 4. MAGNE-FILTER AIR CLEANER For clean air year 'round. The electronic Magne-Filter air cleaner, installed in the return duct"of any winter or summer air conditioning sys tem, traps even the smallest dirt particles, removes pollen, air-bome bacteria, dust and smoke. 5. MOHAWK WINTER AIR CONDITIONER For gas. De luxe cast iron winter air conditioner for large or small homes. Preheated air offers fuel economy, extra efficiency. Ribbon burner for any type of gas. Eight sizes, with A .G.A. input ratings of 80,000 to 300,000 Btu. 6. WINTERGLO WINTER AIR CONDITIONER For oil. Steel utility type unit for small homes and individual apart ments. Factory assembled and pre-wired; two sizes, 85,000 and 105,000 Btu output at bonnet. Side or bottom return air inlet. Underwriters' listed with flange type Arcoflame Burner for less than standard clearances. 7. WINTERWAY WINTER AIR CONDITIONER For oil. Steel basement type unit with right or left side flue connec tion, solid base pan with leveling screws for quick installa tion. Underwriters' listed with flange type Arcoflame Burner. Three sizes, with 100,000 to 150,000 Btu capacity at register. 8. SENECA WINTER AIR CONDITIONER For gas. Low cost steel gas fired basement unit for small and medium size homes. Cleanable heating element. Four sizes with A.G.A. inputs of 85,000 to 150,000 Btu. 1329 American Radiator & Standard Sanitary Carp. i - Heating Systems Warm Ail Furnaces American Radiator & Standard Sanitary Carp. Gas and Heating Systems 4 Oil Burners, Water Heaters, Accessories 1. ALLERTON WINTER AIR CONDITIONER For all fuels. Moderately priced steel unit. Four sizes, 20 to 27 in. shell , diameters, from 86,100 to 127,900 Btu capacity at register. 2. CLIFFDALE WINTER AIR CONDITIONER For all fuels. Rugged steel unit. Two sizes, 30 and 34 in. shell diameters with 162,500 and 177,000 Btu capacity at register. 3. NAVAHO FLOOR FURNACE For gas. Shallow steel unit for homes with or without basements. Factory assembled. Available with floor grille or dual wall register, automatic con trols. Three sizes, with A.G.A. inputs of 25,000 to 50,000 Btu. 4. SHAWNEE WARM AIR FURNACE For gas. Compact steel furnace for economical heating. Cleanable heating ele ment. Two factory assembled sizes, with A.G.A. inputs of 65,000 and 80,000 Btu; three larger sizes, with inputs of 105,000 to 140,000 Btu. 5. KENWOOD WARM AIR FURNACE For all fuels. Cast iron furnace for hand fired coal. Heating element of durable cast iron. Dependable and economical. Four sizes, from`18 to 24 in. fire pot diameters--53,000 to 81,200 Btu capacity at register. 6. ARLINGTON WARM AIR FURNACE For all fuels. Modem steel furnace, in pipe and pipeless models, for coal (hand fired or stoker) or oil. Readily adaptable to gas: Heavy steel heating element. Four sizes, from 20 to 27 in. shell diameters--67,800 to 100,800 Btu capacity at register. 7. CLIFTON WARM AIR FURNACE For all fuels. Quality steel furnace for larger installations. Burns all fuels. Readily adaptable to gas. Two sizes, 30 and 34 in. shell diameters--128,200 and 139,300 Btu capacity at register. 8. BLOWER-FILTER UNIT For converting existing gravity installations to forced air. Replaceable filters remove dust, dirt and pollen. Quiet, dependable, rubber mounted motor, built-in overload protection. Six sizes, from 9 to 21 in. 1330 1. RADIANTRIM PANELS Replace ordinary baseboards. Provide all the advantages of both connected and radiant heat. Sheet metal accessories also available for complete installation. 2. SUNRAD RADIATORS Recessed or free-standing. Need no enclosure. Two sizes: 5 in. deep x 20 in. high and 7\ in. x 23 in. Inlet grilles if desired. 3. 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. 4. 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. Bums all gases. Three models, with A.G.A. inputs of 60,000 to 335,000 Btu. 5. BUDGET WATER HEATER--Approved by A.G.A. Heats water automatically, stores it for instant use. White enameled jacket, black trim. Thrifty and dependable. Three sizes--20, 30 (shown) and 40 gal. 6. ARCO RADIATORS--Modern, slim tube radiators that occupy less space and give more heat. Available in four widths--3, 4, 5 and 6 tubes--and four heights--19, 22, 25 and 32 in. 7. ARCOFLAME OIL BURNER--Listed by Underwriters' 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. 11 "DETROIT" HEATING CONTROLS AND ACCESSORIES-- A complete line of Heating Controls and Accessories for all types of Bystems. 8. No. 861 Hurivent'Vent Valve (for mains) 9. No. 300 Multiport Adjustable Air Valve 10. No. 500 Airid Air Valve 11. No. 999 Packless Radiator Valve 12. No. 5000 Variport Airid Adjustable Air Valve 13. No. 116 Radiator Valve. Complete line of elbows and fittings for all types of hot water systems. 1331 I Heating Systems Boiier-Bumer Aldrich Company 121 E. Williams St., Wyoming, Illinois Boiler-Burner Units, Domestic and Commercial Oil Burners Aldrich Boiler-Burner Units--available in 7 sizes for Hot Water Heating, Steam Heating, and Hot Water Supply--de signed for home, apartment, garage, club, restaurant, hotel, and factory installations. Gages, covers, and trim furnished to suit model and unit type ordered. Heavy-duty, double-spiral hot water coils factory-installed and tested in SC and WC models. Matched Al drich Oil Burner with each unit. Stand ard equipment includes full set of basic automatic controls. Series BG Boilers are gas-fired with A.O.A.-approved burn ers for first five sizes. Oil and gas burners are readily interchangeable. Welded steel fire box lined with cast re fractory having high resistance to de terioration. Large burner - mounting plate provides access to fire box for re placement of combustion chamber. ' Ex tra thick wool insulation blanket pro vides high insulating value and minimizes heat loss through radiation. Universal tappings on all models except "Bantam." BOILER-BURNER UNITS Sizes--Specifications--Dimensions Size ot Boiler Bantam 118 160 225 315 514 808 Rating Sq. Ft. Hot Water EDR.............................................. 660 750 1000 1500 2100 3300 5000 Rating Sq. Ft. Hot Water Standing Radiation.............. Rating Sq. Ft. Steam EDR... 440 425 500 500 650 1000 1400 2200 3333 630 935 1275 2025 3000 Rating Sq. Ft. Steam StandingR&diation........................... 285 Rating BTU Per Hr. (Max.).. 100.000 333 118,000 420 160,000 620 225,000 850 315,000 1350 514,000 2000 808,000 Water^Heater Delivery GPH @ 100 Rise................................ Storage Capacity Gallons....... Firing Rate--GPH Maximum Firing Rate--GPH Minimum Firing Rate--GPH Best......... Model Burner Furnished........ Sq. Ft. of Heating Surface-- Ena Main Shell (Inside).......... Height of Main Shell................ Dia. of Fire Box (Inside)........ Height of Fire Box..................... Number of Tubes...................... Length of Tubee......................... Output Hot Water! wc--opm Coil & 100 Rise J bc--gpm 93 20 1.00 .65 .75 CXI 17 m* 42$*' 12* 21 16 15$*' 3 3 125 28 1.25 .75 1.00 SAX1 21 19* 46$*' 14$*' 24' 16 15$*' 1.75 2.00 190 38.5 1.65 1.25 1.35 SAX2 27 21' 50$*' 16' 20 19$*' 2.00 2.75 280 72 2.75 1.75 2.00 SAX3 24k'. 58$*' 19* 30 23$*' 2.66 3.67 450 99 3.65 2.4 2.5 SAX3 28* 66M' 2JH* 42 30$*' 5.25 6.75 610 120 5.7 3.7 4.5 BX 32* 66$*' 27' * 60 29$*' 6.50 8.00 850 170 9.00 6.00 7.5 BX 38f 70Jf 3#f 94 31$* 7.25 10.00 Shipping Weight Lbs.--Boiler 440 697 843 1170 1760 1975 2370 Shipping Weight Lbs.-- Burner Only............................. Shinning Weight Lbs.--Total. 77 517 90 787 90 90 90 100 100 933 1260 1850 2075 2470 ALDRICH OIL BURNERS--Capacities from 0.75 gph to 19 gph. Models SAX-CX-BX-JU. 6 sizes, 4 models for domestic and commercial warm air, steam, or hot water systems. UL listed. SAX (illustrated) 3 firing ranges--0.75 to 1.35; 135 to 2-2 to 4.5. Model CX 0.75 to 2. BX 4 to 8.5. JU 7 to 19.00 gph. 1332 MODEL DESIGNATIONS Without Coil Steam Heating Hot Water Heating Hot Water Supply S W HGS* With Coil Steam Heating Hot Water Heating Hot Water Supply SC wc - * Galvanised, with dress jacket. Heating Systems Boilers & Radiators Unit Heaters Brown Products Company 97-12 Metropolitan Ave., Forest Hills, New York Brown Bayce-Heetis a"high-output" baseboard designed for residential and commer cial use. This smart looking new unit has a rating of 1100 Btu at 215F. (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 toallowmoreefficientaircirculation. For use on forced hot water or two pipe steam system. Heating element: M in. copper tubes expanded into rectangular beaded aluminum fins for greater strength and heat transfer area. TSlt&tvjt. OSCHUffl Automatic Oil-Fired Boiler Burner Units Domestic Water Heaters Available in 6 sizes for hot water radiation 68,000-472,000 Btu/hr. For steam radiation 5 sizes available from 93,000 472,000 Btu/hr (388-1965 sq ft EDR). Boilers come with built-in combustion chamber and flange mounted gun-type oilburner with controls. Available with 3, 4, or 5 gal instantane ous coil for hot water. Publication 100-2. mm CONVECTOR UNITS Brown Heet Convector Units in the dis tinctive 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. Free 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). H in. copper tube--expanded into aluminum fins. Publication 600-1. Unit Heaters Horizontal Suspended Type Brown Heet Unit Heaters are available in capacities from 2,400 to 240,000 Btu/hr (100-1000 soft EDR) operating at 2 lbs steam pressure 60 F air entering. Hot water use is optional. Heat ing element consists of in. OD copper tubes expanded into aluminum fins providing positive permanent mechanical bond. Publication 500-1. 1333 i ' Heating Systems Boilers. Gas and Oil 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, non-explosive 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. A Bryan Copper Tube Boiler never ex plodes. The worst that can happen is a , split tube which may be replaced in a few minutes' time by an inexperienced person. Bryan Copper Tube Boilers are engi neered expressly for oil or gas firing, where the flame is either on at full.intensity 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 of 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 Boilers Commercial Heating Boilers High Pressure Boilers 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 2250 to 4400 sq ft of steam ra diation or 3600 to 7050 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 clean ing plants, laundries, milk plants, tire repair shops and many others find them ideal for their operations. Heating Systems * BOILERS and RADIATORS Irvington-on-Hudson, N. Y. There's a Burnham for Every Purpose--Catalog No. 82 Sent on Request Base-Ray Radiant Heating Hy-Power Model Base-Ray--Ratings --2.35 sq ft per lineal foot. Tappings-- % in. at bottom only of both end sec tions. Sections are 7 in. high, 2 in. thick and in 12 and 24 in. length. Burnham Radiant Raditor--Two heights. 20 and 23 in. Ratings, 2.25 sqft per sec tion and 3.40 sq ft per section. Burnham Slenderized Radiators--three to six tubes in all heights 19 in. to 33 in. At left: No. 1, 2, 3 and 36 in. Series--All Fuel. 230 to 4920 sq ft. Steam and 370 to 7880 for Water. Center: PACEMAKER Boiler for oil firing 270 to 710 sq ft for Steam and 490 to 1270 sq ft for Water. Bight: YELLO-JACKET Boiler (with extended Jacket) All Fuel Convertible 305 to 935 sq ft for Steam and 490 to 1600 sq ft for Water. 50 in. Twin-Section--4500 to 14,600 sq ft for Steam and 7200 to 23,360 sq ft for Water. Welded Steel Boiler--Capacities from 2500 to 35,000 sq ft for Steam and 4800 to 56,000 sq ft for Water. Furnished for coal, oil or stoker firing. 1335 . Heating Systems Boilers, Radiators, Furnaces, Heating Accessories Crane Co. BOILERS, BASEBOARD PANELS, RADIATORS, FURNACES, VALVES, FITTINGS, PIPE, WATER AND' STEAM . SPECIALTIES, CONTROLS AND PLUMBING MATERIALS General Offices: 836 South Michigan Avenue, Chicago S, Illinois Nation-Wide Service Through Branches, Wholesalers, Plumbing and Heating Contractors CRANE OFFERS EVERYTHING IN HOME HEATING CRANE 16--A completely packaged boiler-burner unit. Patented Crane Sustained Heat Principle assures fuel economy. Oil burner is concealed be neath handsome jacket. For steam or hot water systems. CRANE 20--A highly efficient boiler in corporating Crane patented water baffle and increased ceiling heating surface. For hand or stoker firing of coal, or for oil or gas conversion. Steam or hot water systems. CRANE 14--A compact wet base boiler ideal for basement or utility room instal lation. May be had for steam or hot water system--to burn coal or coke, oil or gas. CRANE-LINE 2WG--Only 33 inches high, this efficient gas boiler will heat the average 5-room house. Designed for the most economical burning of. gas. For hot water systems. CRANE 30 & 40--Large boilers for schools, hospitals, public buildings, etc. For steam or hot water heating. Will burn coal or coke--oil or gas. VALVES--FITTINGS--The Complete Crane line of valves and fittings offers all necessary piping items for any heat ing system. ALSO--A complete line of gas, oil and coal-fired Furnaces, Unit Heaters and Floor Furnaces. For information on Crane Heating, con sult your Crane Branch or Crane Whole saler. Crane 40 Boiler 1336 Crant-Line tWG Deluxe Boiler Crane Co. Heating Systems Boilers, Radiators. Furnaces, Heating Accessories ^ - " CRANE RADIANT BASEBOARD HEATING Easy to install--special panel tool assures quick, positive assembly. Matching wood baseboard permits con tinuity of panels around wall--simplifies Type RC provides radiant and convected heat. Type R, solid front, provides radiant heat only. Both are 9 in. high. comer connections. When wall space is limited, i.e., kitchen and bathroom, Crane panels may be effectively installed at the ceiling. CRANE COMPAC RADIATORS Slender in line--modem in design--give more heat--use less space. For free standing or recessed installation, steam or hot water. Built in sizes to suit every need--in 3, 4, 5 and 6-tube types of 6 to 56 sections. Replace ordinary radiators with little or no change in ' piping. WATER SPECIALTIES Hot water specialties to suit every in stallation. They include water heaters, circulators and flow control valves--all top-quality equipment. Newly engineered. Crane-Line oil bur ners provide heating comfort at low fuel costs. Simplified design and sturdy con struction reduce maintenance. "Spreader Flame" principle of construc tion and operation. Produces the very best burning characteristics and feliminates losses due to incomplete combus tion or excess air. Hrre--ating Systems - Baseboard Radiation Boiler Burner Units - General Automatic Products Corporation EMRAL ufomalk 2300 Sinclair Lane Baltimore 13, Md. Manufacturers of a Complete Line of Gas and Oil Heating Equipment' FLOORLEVEL BASEBOARD RADIATION FLOORLEVEL BASEBOARD HOT WATER HEATING "J" SERIES BOILER BURNER (Oil Fired) A compact unit especially designed for FLOORLEVEL installations from 200 to 650 sq ft of hot water radiation. A floor complete unit containing tankless do (C) Center of ele- mestic hot water, built-in combustion chamber and oil burner. (D) Floor to bottom DE-AIRATOR TANK of panel 1' (E) Screw holes in bracket, center [to center 6 (F) Floor to center ' of lower screw E holes (G)Back of panel . to wall (H) Wall to center of element 1%' A complete unit for the elimination of air in hot water heating system; also * .J (I) Opening, top of replaces the expansion tank. moulding 1* panel to lower . Specifications "E" SERIES BOILER BURNERS (Oil Fired) Water Temp. Capacity (per Un. foot) 200F 600 Btu 190"F 445 Btu 180F 390 Btu Equiv. 3H eq ft per lin. ft. at 200* water. - A complete hot water heating system to fit all types of homes. Easy to handle and install. Radiation is concealed in attractive metal baseboard which re places the normal wooden baseboard. A COMPLETE PACKAGE For larger installations--440 to 1760 sq Packaged in 3 cartons . . . each package consists of enough material to do the average installation for the amount of square footage required. The packages are so sized in 6 assortments to fit any size installation. Carton No. 1 con tains the fin type heating element, carton No. 2 contains the front paneling and top moulding and carton No. 3 contains the panel and moulding splices, wall brackets, end terminals, miter corners, element orifices and wood corner blocks. ft hot water radiation. Vertical water tube wet base boiler. ASME approved. All models equipped with 4 gpm tank less domestic water coils. All units fully enclosed and well insulated- ' CONVERSION OIL BURNER' All sizes with capacity of 1 to 20 gpm. G/A vibration free universal coupling. WARM AIR CONDITIONER (Oil Fired) Highboy and Lowboy models, 85,000 to 200,000 Btu capacity. Burner & con trols. 1338 Heating Systems Boners, g.s Hook & Ackerman, Inc. 63-56 Shakespeare St. PITTSBURGH 4, PA. 9 East 40th St. ; NEW YORK 16, N. Y. HYDROTHERM The Midget Automatic Gas Heating Plant For residential, commercial and Industrial hot water systems. HYDROTHERM is engineered for max imum life and maximum fuel economy and fully AGA approved for use on Manufactured, Natural and LP gases. Outstanding for: Radiant heating systems Convection heating systems ' Gravity hot water systems Volume hot water heating . . MODEL tHWS v>/o Jacket 400 q ft InetaUcd Radiation S7S tbc, 18 in. x 87 in.xSOin. Booster service for 180 deg sterilizing water MODEL tHWS 888 cq ft InetaUcd Radiation 850lbs, 18 in. x t8 in. x 88 in. CONSTRUCTION:--All cast iron, the HYDROTHERM absorption unit has hori zontal sections, deep ribbed, overlapped and connected in zig-zag. This fully patented design is to give maximum heat transfer surface for a minimum water vol ume-resulting in great efficiency and quick pick up. Absorption unit is furnished completely assembled and factory tested at 250 lb hydrostatic pressure. All controls including automatic gas control valve, Baso safety pilot, pressure regulator, aquastat and tridicator are enclosed in De Luxe jacket of Hammeroid finish. CAPACITY RANGE OF HYDROTHERMS Will AGA ratings Supply Hydrotherm Model No. Input Btu/Hr Sq Ft Output Btu/Hr Output Sq Ft Water Installed Radiation Water 170* F 2 HW 2 45,000 36,000 240 180 2 HW 3 2 HW 5 *5i 2M HW 3 ,3 2H HW 4 2H HW 5 17020,,000000 210500,,000000 250,000 57,000 18200,,000000 210600,,000000 384 530 800 1066 1333 288 400 600 800 1COO d 2M HW 6 P 2J4 HW 2H HW 2H HW 807 2H HW 10 300,000 350,000 400,000 450.000 500,000 240,000 280,000 320,000 360,000 400,000 1600 1866 2133 2400 2666 1200 1400 1600 21080000 Capacity for Hot Water Storage Tanks Gallons per Hour for Temperature Rise Shown 40 60 80* 100" 120" 106 70 170 113 54 85 4628 35 56 238 158 119 95 79 357 237 178 142 118 476 317 238 190 158 595 396 297 238 198 714 474 356 284 236 833 554 416 332 276 952 633 475 380 316 1071 713 535 428 356 1190 792 . 594 476 896 1339 Ship ping Weight Lbs. 160 250 375 600 700 810 1200 1300 1400 1510 1620 ry___j . o _ Boilers, Radiators. nQtl7lQ oyStGlTlS Convectors, Accessories The National Radiator Company MODERN DESIGN A HEATING EQUIPMENT Johnstown Pennsylvania Branch Offices: Bm.tq.obe, 2100 St Paul Street Boston. Ne^u^ Sti^t .Bottalo, 17 Wells Street Chicago. <00 West Madison Street Detroit, *736 TwlIBi Street New Yobs, 60 EMt 4aid StoMt Philadelphia. 1218 Cherry Street PrrrsBOBQH. 125 Fust A venue.Ria.MOND,308 West Cary Street San Francisco, 681 Market Street Washington, D. 4043 Georgia Avenue, NW. national heat extractor cast iron boilers. Designed to fit the requirements of automatic heating, Na tional Heat Extractors are provided with many features to insure high operating efficiency and maximum fuel economy. These include extended heating surface, multiple-flue section construction, effectively insulated 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. . _ .. NATIONAL OIL HEATING UNITS, cast iron or steel, provide complete "one package" equipment designed for maximum 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. _, . , NATIONAL GAS BOILERS are modern, compact and designed exclusively for gas firing. Cast iron sections for long life and dependability. Tapered flues, long zigzag fire travel and heavy insulation insure efficiency and economy. "500" and **400" Series HEAT EXTRACTOR BOILERS Boiler Series 210000 Oil Beating Unit 300 400 500 OIL HEATING UNITS Net I-B-R Ratings. Sq Ft Steam Watei 170 to 470 350 to 830 700 to 2300 2500 to 6000 4000 to 10300 270 to 855 560 to 1560 1120 to 3835 4000 to 9600 6400 to 16480 GAS BOILERS Cm Boiler Type of Unit Net Ratings, Sq Ft Steam Water j Net Ratings, Sq Ft A.G.A. Approved Boiler Series 1 Steam Water 100 Series Cast 200 Series Cast Residential Steel.. 230 to 470 400 to 880 275 to 700 430 to 855 730 to 1560 440 to 1120 j 20 and 22 30 and 33 40 and 44 55 110 to 390 355 to 985 445 to 1920 1195 to 9690 205 to 715 650 to 1725 810 to 3250 2080 to 15505 1340 The National Radiator Company Heating Systems Radiators, Boilers, Convectors, Accessories is'-is'-ss' Sud 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 the Hartford Steam Bailer Inspection and Insurance Company. The 18 in. and 23 in. Series RESIDENTIAL STEEL BOILERS (for oil or gas) 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 installations. The Commercial Senes 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 18' and 23'............ 28', 29*, and 39*... SBI Net Ratings, Sq Ft Steam Water 275 to 700 570 to 3000 440 to 1120 910 to 4800 Boiler Type Automatically Hand fired.............. SBI Net Ratings, Sq Ft Steam Water 3000 to 35000 2500 to 29170 4800 to 56000 4000 to 46670 THE NATIONAL PACKET: A compact, all-in-one automatic oil-fired heating unit for small homes. An integral tank less heater provides domestic hot water. Unit also available with white enclosing cabinet. SBI Net rating 510 sq ft Water. The National Packet used with Na tional Art Baseboard provides a modern, low cost,' easy-to-install complete hot water heating system for small homes, motels, diners, stores, etc. Art Baseboard NATIONAL ART BASEBOARD--Re places customary wooden baseboard. Two types, BF (flush-to-wall) and BR (recessed under plaster). Heating ele ment consists of helical fin bonded to a copper tube. Designed for use with forced circulation hot water systems. NATIONAL ART CONVECTOR--A nonferrous convector, for flush and semi- or full-recessed installation. Aluminum fins bonded to copper tubing comprise the heating element. Enclosures are made in a variety of types for residential or commercial installation. NATIONAL AERO CONVECTOR-- Heating element 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--Blend inconspicuously with most decorative schemes. Compact proportions require minimum floor space. A wide variety of sizes and ratings can be furnished. 1341 Art Radiator Heating Systems Boilers. Steel DIVISION United States Radiator Corporation Detroit 31, Michigan Sales Offices in Principal Cities u * r os. Pacific Standard Firebox Boilers Pacific Split-Firebox Boilers 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 minimurns, and rated in ac cordance with Steel Boiler Institute 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 6470 to 42500 sq ft SBI rating steam and in cor responding capacities for water. { v PACIFIC FRONT SMOKE OUTLET BOILERS Pacific Front Smoke Outlet Boilers for band, 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 (as 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. 1342 Descriptive Bulletins on Pacific Commercial Boilers will be mailed on request Heating Systems BoQers Steel /acc/fcc P IV ISIO N United States Radiator Corporation Detroit 31, Michigan Sales Offices m Principal Cities NENBCI *t v s o#. 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 Bq 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 sq ft steam and in corresponding capac ities for water. . Pacific Round Steel Boilers Pacific "O'* Series Boilers Descriptive Bulletins on Pacific Residential . Boilers will be mailed on request 1343 Pacific Residential Square Boilers / Heating Systems Boilers, Cast Iron ZMtedjSiates Radiator @*Ponmorr Member General Office, Detroit 31, Mich. Branches and Sales Offices In Principal Cities - Reg. U. 8. Pat. Off. The United States Radiator Corporation carries a complete line of hand, stoker, gas and oil-fired boilers for steam or hot water heating, warm air furnaces, gas burners and oil burners, radiators,, baseboard convectors, controls and heating ac cessories for residential, commercial and industrial heating. U.S. 12 All-Fuels Boiler (Oilratings shovm. For coal-fired ratings, write for Catalog A-S99.) U.S. Radiant Baseboard Designed to operate with forced circu lating hot water systems, U.S. Radiant Baseboard replaces ordinary baseboard. It is light in weight, of all-steel construc tion and is roughed-in and installed exactly as standard radiator practice. Radiant surfaces, waterways and finned surfaces of U. S. Radiant Baseboard are copper brazed into a single pressure-tight unit. Exterior surfaces are specially treated,1{then protected with grey zinc chromate primer. Packed in individual cartons, distinctly marked, U.S. Radiant Baseboard is shipped in unit lengths of 2 to 12-ft in clusive in increments of 1-ft. Write for catalog AR-29G. Boiler <No. pi 12-30 12-40 12-50 12-60 I = B -- R Net Ratings D.C.I.R. Sq Ft 1000 Btti/hr Steam 230 310 390 470 Water 430 570 715 855 Steam 55 74 94 113 Water 8665 107 128 IB =R Gross Output 1000 Btu/br 86 114 143 171 U.S. Solar Flame Gas Conversion Burners are A.G.A. rated and are available for steam, hot water and warm air systems. 2 models. Capacities from 75,000 to 300,000 Btu's/hr. U.S. Solar Flame Oil Burners are avail able for steam and hot water boilers and warm air furnaces. 3 models. Capacities from 0.6 to 15 gal/hr. U.S. Fin-Ray Baseboard Radiation U.S. Solar Flame Gas Burners US. Fin-Ray Baseboard Radiation for homes and offices is furnished in 1 in. and 1-1/4 in. pipe sizes. For commercial applications U.S. FinRay Commercial Radiation is furnished 1-1/4 in. and 2 in. pipe sizes. . Write for catalogs AR 319B (Baseboard) and AR 318 (Commercial) for data and specifications. U.S. Gas Boilers include a complete range of sizes and capacities from 480 to 12,480 sq ft for steam heating, and from 240 to 20,000 sq ft for hot water heating. U.S. Gas Boilers are furnished with necessary control equipment and are completely automatic in every opera tion. All units are A.G.A. approved. THINTUBE RADIATORS 3-Tube 5-Tube Heights Id. 25 Per Section Heating Surface 1.6 Sq Ft 4-Tube a -nrsaFt 25 2.0 Sq Ft 22 2.1 8q Ft 25 2.4 Sq Ft__ 6-Tube 19 2.3 Sq Ft 25 3.0 Sq Ft 32 3.7 So Ft 1% in. Centura. 1344 Heating Systems. Boilers, c.st iron sjjxiicjjjjiajas RADIATOR WRPORATIOX~ OMI t ***** *i **1 *l |*r*MS General Office, Detroit 31, Mich. Branches and Sales Offices in Principal Cities U.S. 2 Oil-Fired Boilers BNo?P 2-03 2-04 2-06 I = B"R Net Ratings D.C.I.R. Sq Ft 1000 Btu/hr Steam 350 500 650 800 Water 645 910 1170 1425 Steam 84 120 156 192 Water 214 Member rW ni Re*. U. 8. Pet. Off. (Oil ratings shown. For Stoker and Hand _________ratings, write for Catalog A-417B) 28-30 28-35 28-40 28-45 28-50 28-55 28-60 28-65 28-70 28-75 850 1510 204 227 1055 1260 1470 1850 2185 2530 253 302 353 278 328 380 1690 2880 406 432 1900 3210 456 482 2120 3560 509 534 2340 3900 562 585 2570 4255 617 638 2800 4600 672 690 U.S. Vertical or Hori zontal Unit Heaters U.S. Vertical or Horizontal Unit Heaters are available with either 60 cycle AC or 25 cycle AC or DC motors in a wide range of sizes and capacities. Optional control equipment for special applica* tions may be obtained at extra cost. Write for catalog. 1345 Heating Systems* Castiron Frank Prox Company, Inc. Office and plant 1201 So. First St. Terre Haute, Ind. PROX BOILERS For Large Installations in Schools, Theatres, Apartments, Churches, Hospitals, Hotels', Etc. Write for complete catalog. CAN BE FURNISHED WITH A 22 IN. HIGH CAST IRON BASE FOR AUTOMATIC FIRING 22 in. High base plus 38 in. from normal grate line to crown sheet allows you a total of 60 in. from floor to crown sheet making it convenient for the installation of stoker, oil burner, or gas conversion burner. Front base opening will be made to suit your specifications at no extra charge when so ordered. 6 POINTS PARAMOUNT IN CHOOSING BOILERS 1. CONTINUOUS SERVICE--Any heat ing plant will break if carelessly oper ated. Broken sections in Prox Boilers can be plugged off and heat maintained. 2. FUEL ECONOMY--Short, wide fire box design, full three layer fire travel, low stack temperature, self cleaning Sues, conservative ratings. 3. LONG SERVICE, SAFETY--Prox cast sectional Boilers represent maxi mum permanence as compared to steel construction. 4. QUICK, DRY--STEAMING--Low water line, small waterways, quick cir culation, dry steam assured by steam separating header over Prox Boilers. 5. REPAIR ECONOMY--Remove any section like tilting book from bookcase, eliminating tearing down and destroying expensive covering. 6. INSTALLATION ECONOMY--Take flow direct from large steam separating header, saving extra cost of additional header construction STEAM WATER LINE <(gg; g fc] Regular Boiler Number BB-60 510 511 812 813 814 815 816 517 518 819 S20 821 822 S23 824 S25 Guaran teed Rating Steam 11440 12540 13640 14740 15840 16940 18040 19140 .20240 21340 22440 23540 24640. 25740 26840 27940 Returns (inches) ______ 1-3 1-3 1-3 1-3 1-3 1-3 1-4 1-4 1-4 1-4 1-4 1-4 1-4 1-4 1-4 1-4 STEAM AND WATER Grate Area (sq ft) Heating Surface (sq ft) 24.50 24.50 24.50 24.50 27.60 27.60 27.60 27.60 30.60 30.60 30.60 30.60 33.70 33.70 36.70 36.70 570 627 684 741 798 855 912 969 1026 1083 1140 1197 1254 1311 1368 1425 1346 Flows (inches) 111122222222------------1888888888880 2222----11110000 WATER Returns (inches) 4-4 4-4 4-4 4-4 4-4 4-4 4-4 4-4 4-4 4-4 4-4 4-4 4-4 4-4 4-4 4-4 Regular Boiler Number BB-60 W10 Wll W12 W13 W14 W15 W16 W17 W18 W19 W20 W21 W22 W23 W24 W25 Guaran teed Water Rating 17160 18810 2202411600 23180 25414 27060 28710 30360 32010 33660 35310 36960 38610 40260 41910 Heating Systems % Rdiaon Shaw-Perkins Manufacturing Company 201 E. Carson St. . Pittsburgh !?), Pa. Cutaway--Shaw Modd 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 (1 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*^ in. to 32J in. Supply 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 heating 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 " 1347 I " Heating Systems Boners, cast-iron Allentown, Pa. Cincinnati, Ohio Sales Representatives 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 Birmingham, Ala. Detroit, Mich. Kansas Crrr, Mo. New Yoke, N. Y. San Antonio, Texas ' Knoxville, Tenn. Philadelphia, Pa. Seattle, Wash. Boston,Mass. Grand Rapids, Mich. Memphis, Tenn. Pittsburgh, Pa.' Spoxane, 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 uA**t "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. 1,800 TO 42,500 SQUARE FEET, STEAM Steel Commercial Heating Boilers--Ex clusive peaked firebox design aids in making the "A" Boiler quick steaming and efficient. Space for either Btorage tank or instantaneous type service water coils. Larger sizes can be cut in half to move through narrow openings. ".A" Series 570 TO 3,000 SQUARE FEET 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 instal lation of oil burner or stoker. Available with domestic hot water coils and attrac tive insulated jacket. 1348 C" Series Spencer Heater Heating Systems Bouers. steel 320 TO 900 SQUARE FEET STEAM, NET LOAD Steel Residential Heating Boilers--Ex cellent for small homes requiring econo mical heat and instantaneous hot water. Available with attractive beauty jacket. "IV' Series 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. --------- -- ~ t ~ . .uai, dlfijun Cast Iron Sectional Magazine Feed Boilers-- Highly efficient for burning economical buckwheat anthracite or pea size coke. No motors or moving parts. Fuel feeds automatically down unique Spencer slop ing grate with minimum attention. Per mits conversion to oil heat. 1430 TO 4,510 SQUARE FEET, STEAM UL>* Series Cast Iron Magazine Feed Boilers--Resi dential or commercial: An economical heating unit ' for use with buckwheat anthracite. No motors or moving parts. Fuel feeds automatically down unique Spencer sloping grate, and requires only five to ten minutes' attention each day. May be converted to other types of fir ing if desired. 5,000 TO 18,740 SQUARE FEET, STEAM Steel Tubular Magazine Feed Boilers-- For larger buildings, apartments, indus try. One of the most economical boilers on the market. Designed for economi cal sizes of anthracite. Magazines hold enough fuel for 24 hours. Automatic feed, no moving parts. "V"-shaped duplex grate construction allows firing half of boiler during mild weather. 1349 / Heating Systems Boilers, cast-iron The H. B. Smith Company, Inc. Westfield, Mass. Branch offices and Sales Representatives in Principal Cities A complete line of modern cast iron sectional boilers for residential* commercial and industrial heating and for domestic hot water supply 15-20-25 SMITH-MILLS BOILERS Capacities 200 sq ft to 2275 sq ft steam radiation. This complete line of mod ern push nipple boilers is available in models for oil, gas, stoker and hand . firing. Provisions have been made for built-in domestic hot water heaters and controls. to m! MILLS WATER TUBE BOILERS Series 24-34-44 Capacities 900 sq ft to 13,380 sq ft of steam radiation. Independent header type construction--tens of thousands of these famous Mills Boilers are installed in schools, hospitals, apartment houses, stores, and other commercial and public buildings. Models for hand and all types of automatic firing. U MQU 42 AND 60 SMITH BOILERS May be used in batteries for heating loads up to and over 100,000 sq ft steam radiation. Many of these large units installed in industrial plants furnish steam for process requirements as well as for heating and domestic hot water. 60 Smith SMITH HY-TEST BOILERS Smith Hy-Test Boilers for hot water supply, are available in several models and many sizes for tank capacities to 20,000 gal. Constructed of the finest quality grey iron castings, these HyTest units are carefully tested at high pressures before shipment. The No. 17 series, for example, is tested at 350 lbs hydrostatic pressure--a higher test pres sure than is customary for cast iron boilers. IT HY-Tat Complete catalog information describing Smith boilers is filed in current issues of Sweet's "Architectural" and Domestic Engineering Catalog Directory 1350 Healing Systems % Boilers, cast-iron Weil-McLain Company Manufacturing Division: Michigan City, Ind. and Erie, Pa. General (Wees: 641 W. Lake Street, Chicago 6, 111. , NEW YORK OFFICE: 501 Filth Avenue Weil-McLain Roller and Radiator service ia made conveniently available through local atoeka earned by Weil-McLain Distributors in moot of the important distributing centers. <-- Nos. 57,67,77,87 All-Fuel Boilers Conversion type boilers for hand or automatic firing. Connected Load Rat ings: Steam 210 to 2300 sq ft, Water 340 to 3835 sq ft. Square-Type Boilers -- Sectional boilers for larger installa-. tions 28, 40 and 44 Series. Connected Load Ratings: Steam 1,580 to 11,300 sq ft, Water 2700 to 18,080 sq ft. <-- No. B-5 and B-6 Oil Heating Units Boiler burner units available with flush or extended j acket, Type A or Type N burner. Net I=B=R Rating: Steam 325 to .690 sq ft, Water 600 to 1235 sq ft. Type G and H Gas Boilers -- Jacketed gas boilers for natural, mixed, manufactured gas or liquefied petroleum gases. A.G.A. approved. Connected load ratings: Steam 390 to 1240 sq ft, Water 360 to 2160 sq ft. <-- Round-Type Boiler Unjacketed Round Boiler with corrugated heating surfaces for hand or automatic firing. Connected Load Ratings: Steam 310 to 900 sq ft, Water 490 to 1590 sq ft. Snug cast-iron baseboard panels giving combination of radiant and convected heat. A complete line of metal ac cessories for finishing is available^ Height 7-J4 in. Rating 2.4 sq ft per - lineal foot. . Raydiant "Recessed" --* A Radiant convector type all cast-iron Radiator. Made in "Recessed," also Partially Recessed types. . -- Solray Radiator Free standing, all cast-iron Cabinettype Radiator with metal cover top. Three heights: 21, 24, and 27 inches. One depth in 18 in. height. Junior Radiator --> Smaller Tubular type Radiation which conserves space. Available in 1| in. centers in 3, 4, 5 and 6 tube widths and 13 to 32 in. heights. 1351 Heating Systems BoneTM, steel The Babcock & Wilcox Co. 85 Liberty Street, New York 6, 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 Piping.. .Refractories.. .Process Equipment. Heating Systems Boners, steei Cleaver-Brooks Company 465 E. Keefe Ave., Milwaukee 12, Wisconsin Cleaver-Brooks Steam Boilers--Self-Contained, Gas Fired. Complete 15 to 500-hp, Oil Fired. Factory Tested 15 to 250 lb psi, Oil & Gas Fired. STANDARD SIZES HP 15 30 50 80 100 125 150 200 250 300 350 400 500 Approx, rated capac ity Lbs. Steam Per 515 1050 1725 2760 3450 4300 5200 6900 8800 10500 12000 13800 17000 Hour 212F. BURN OIL. BURN GAS. BURN OIL & GAS WITH EQUAL EFFICIENCY. Dia grammatic illustration in cross section representative of the Four-Pass design found in Cleaver-Brooks models. The outstanding feature of the Cleaver-Brooks steam boiler is its proven high efficiency . Economy of operation is assured by establishing an efficient flame and then absorbing the maximum amount of heat in the four passes. B & W INTEGRAL FURNACE BOILER, TYPE FM Complete Shop-Assembled Steam Plant This compact, self-contained unit find their steam-load characteristics bet combines all the desirable advantages of ter suited to a battery of these smaller, "packaged" steam plants with the serv shop-assembled units than to a single ice-proved economy and dependability tailor-made installation of the same ag of larger B&W Integral-Furnace water- gregate capacity. tube boilers that have been heavy favor The Type FM boiler is available in ites for years among power companies standardized sizes for steam require and all kinds of industrial plants. ments of 2800 to 25,000 lb per hr at pres The Type FM unit is expressly de sures up to 275 psi. It is unusually sensi signed for small and medium sized tive to load changes; is fast-steaming; plants, institutions, and buildings faced features automatic push-button opera with problems of skilled operating labor, tion with special provisions for safety; excessive fuel consumption, and costly is suitable for outdoor as well as indoor maintenance. Even large operators may installations with gas and/or oil firing. 1352 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 demands and takes into account these conditions: --. 3 settings. - _______ _________ _____, *~,,***v ture of condensate. Pressure of make-up water. Type of fuel available Electric current characteristics. Space and machinery arrangement. Sug gested boiler room layouts. Plant altitude above sea level Look for the "CLEAVER-BROOKS" listing under the boiler Section of your classified Telephone Directory. 1353 Heating Systems til<i`nd Combustion Engineering-Superheater, 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 United States and Canada More than 20,600 C-E Stokers purchased to date C-E SKELLY STOKER--A compact, self-contained unit with integral forceddraft fan, designed to burn either bi tuminous coal or anthracite. Alternate fixed and moving grate bare assure lateral distribution of fuel. Automatic control is standard equipment. Approxi mate range--20 to 300 rated boiler horse power. 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. C-E LOW RAM STOKER--A single retort, stationary grate underfeed stoker for bituminous coals. Approximate range --20 to 200 rated boiler horsepower. C-E SPREADER STOKER--A simple, rugged overfeed stoker designed to burn a wide variety of coals. Fines are burned in suspension and the coarser coal on a grate which may be of either continuous discharge 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. C-E Low Ram Stoker 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 need. C-E Spreader Stoker C-E BOILERS--Comprise all fire tube and water tube types--see typical exam ples on opposite page--including designs to suit all conditions of fuel, load and space. C-E Boilers range'in capacity from. 1000 to 1,000,000 (or more) lb of steam per hour. Separate Catalogs describing each of these products .are available. B 45S-A 1354 Combustion Engineering-Superheater, Inc. Heating Systems Boilers and Stokers C-E PREMIER BOILER AND SKELLY STOKER For small plants from 75 to 375 de veloped hp . . . pressure to 150 psi or higher ... burns bituminous coal or an thracite ... oil or gas. Economical and efficient, the Premier Boiler-Skelly Stoker Unit combines two service-proved components. The Premier Boiler has long been one of the most popular types in small plants. Compact and sturdily built, it can be installed in a minimum of space. Seams are fusion welded and stress relieved. The Skelly Stoker efficiently burns either bitumi nous coal or anthracite. In addition, provision is made for adding burners in the bridge wall for oil or gas firing ... if desired. C-E RE-CIRCULATION STEAM GENERATOR Completely automatic . . . full capacity and pressure In 3 minutes . . . sizes up to 6000 lb per hr . . . operating pressure 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 forced re-circulation and a unique method of feedwater treatment assure minimum maintenance, high efficiency and maximum output per unit of space. Requiring a floor space only 5 ft by 7 ft and a height of but 7 ft, the unit needs no special foundation and is furnished complete with all auxiliaries. Push but ton controlled, it is ideally suited for unattended operation and for either continuous or intermittent loads. 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 operating personnel. It is of symmetrical design, and steam is. released evenly across the full width of the unit. Gas flow is uni form, heat absorption is efficient and draft loss is low; it is essentially a "quick steamer." The boiler is bottom sup ported with no outside supporting steel; there are no seals or slip joints at the grate line to cause air leaks. Type VU-10 boilers are adaptable to stoker firing or may be fired with oil or gas. . 1355 C-E Premier Boiler and Skelly Stoker C-E Re-Circulation Steam Generator C-E Vertical-Unit Boiler, Type VU-10 Heating Systems stf8 Cyclotherm 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 Bpots. 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 io 800 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 Cyclotherm . 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-17,500 Comb. hy. oil and gas C-2800 thru C-17,500 Max. Model No. HP Rating 0600 C-IOOO 01400 02100 02800 03600 04400 06200 07000 08700 010500 012000 013800 017500 1 18 30 40 60 80 100 125 150 200 250 300 350 400 500 STANDARD RATINGS AND DIMENSIONS OutpatBTU 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 41,850 48,840 55,830 69,764 1356 Hot Water Units Equiva Gallons lent Di Per Hr rect Ra (100Rise) 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 Dimensions (Inches) Length Height Width 71 80} 1101 124 152 162 1731 1971 2244 2511 252 252 252 294. 44) 55 55 631 661 731 84) 91) 981 983 1021 102} 1021 1021 271 41 41 451 55 64 68) 76) 813 81J 88 88 88 88 Heating Systems !??"' 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 95,000 to 1,000,000 Btu ASME CODE CONSTRUCTED Dewey-Shepard boilers & water heaters (oil & gas fired) are built on the patented tube with-in a tube principle. All units are jacketed with fiber-glass insulation ready for instant hook-up. Boilers automatically welded. la Oil burners Underwriters' approved. Gas burners A.G.A. listed. Built-in coils optional. Model NET RATING Water, Sq Ft Steam, Sq Ft Btu B 465 290 70,000 C 580 365 87,500 D 700 435 105,000 E 930 580 140,000 F 1,165 730 175,000 G 1,400 875 210,000 H 1,640 1,025 246.000 I 1,865 1,165 280,000 J 2,330 1,455 350,000 K 2,800 1,750 420,000 L 3,730 2.330 560,000 M 4,450 2,780 666,666 Boiler ratines do not include allowance for Built-in Coils. Based on heat emission rate of ISO Btu per sq ft only. For other emission rates see SBI ratine code. OIL OR GAS BOILERS You Get 80% or More Heat Absorption with the Tube within a Tube This "Tube within a Tube" action results in pre-heating the incoming cold water before it coines in contact with the metal surfaces to which radiant heat is being applied. By this application you offer your customers many advantages 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 In the "Tube within a Tube" boiler there is one square foot of heating surface for every gallon of water. This method transfers every possible unit of heat to the water and results in EFFICIENT AND ECONOMICAL OPERATION. ' 1357 Heating Systems Dutton Boilers Division Hapman-Dutton Co. 639 Gibson Street, Kalamazoo, Michigan For Dutton Representatives, see "Boilers'' in Classified Phone Book Fotir 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, Institutions, etc. Healing Systems Boilers, steel Farrar & Trefts Atlanta, Ga. Baltimore, Hd. . Birmingham, Ala. Boise, Idaho . Boston, Mass. Buenos Aires, S. A. Charlotte, N. C. Chattanooga, Tenn. Chicago, III. Cincinnati, Ohio Cleveland, Ohio Cuyahoga Falls, Ohio Dallas, Texas Denver, Colo. Detroit, Mich. Geneva, N. Y. Grand Rapids, Mich. . Incorporated ESTABLISHED 1863 20 Milbum Street, Buffalo 12, N. Y. FARRAR & TREFTS SALES OFFICES Greenville, 8. C. Honolulu, Hawaii Houston, Texas Indianapolis, Ind. Ivyland, Pa. Knoxville, Tenn. Little Rock, Ark. Long Beach, Calif. Lob Angeles, Calif. Louisville, Ky. Marion, N. C. Medford Lakes, N. J.` Media, Pa. Memphis, Tenn. Mexico City, Mex. Milwaukee, Wis. Minneapolis, Minn. Montevideo, Uruguay Nashville, Tenn. New Orleans, La. .. New York, N. Y. Nutley, N. J. Omaha, Nebr. Orchard Park, N. Y. Philadelphia, Pa. Phoenix, Abie. Pittsburgh, Pa. Portland, Ore. Richmond, Va. Rochester, N. Y. St. Catherines, Ont. St. Louis, MoSalt Lake City, Utah San Antonio, Tex. San Francisco, Calip. Seattle, Wash. Syracuse, N. Y. Tampa, Fla. Toledo, Ohio Tulsa, Oxla. Washington, D. C. EconoTherm vxtier circulation diagram shows rotary motion. EconoTherm Models are fully automatic, self-contained, "packaged" units with full Bafety controls. Of 3-pass fire-tube design, they feature a modified Scotch Internal Furnace located off-center in the welded shell. Off-center firing creates.- a rotary:., water circulation, resulting in more uniform water temper ature, fast steaming, a steady water line at all times, and'high quality dry steam. Higher water column above furnace pro vides greater safety, extra efficiency. Rotary combustion in furnace, large steam storage space, and five or more square feet of water heating surface per rated hp combine to deliver a guaranteed efficiency rating of 80 per cent with steam Aroilable in 9 sizes, EconoTherm is a compact power upackage." Requires no heavy foundation or stack. dryness rating of 99 plus 0/0 dry steam . under proper operating conditions. . Induced draft fan pulls gases through boiler for positive draft and fast firing. Only a vent pipe is needed--no expensive chimney or stack! Boiler shell is onepiece welded construction. X-ray in spected, complying with all ASME requirements. Every unit gets full running test and is accompanied with certified ASME Data Report. OTHER DUTTON TYPES These include EconoMlst automatic HRT with 5-way convertible firing (15 to 105 hp), EconoMaster verticals (5 to 60 hp), and EconoMizer models (10. to 25 hp). 4610 (oil) 4820 (oil) 5835 (oil) 5850 (oil) 5865 (oil) 5880 (oil) 5890 (oil) 58100 (oil) 58125 (oil) ECONOTHERM--RATINGS AND DIMENSIONS ECONOTHERM Model Number 4710 (gas) 4720 (gas) 5735 (gas) 5750 (gas) 5765 (gas) 5780 (gas) 5790 (gas) 57700 (gas) 57125 (gas) Sq Ft Water Heating Surface 125 250 375544 650 814 905 1000 1252 . Lbs Steam Per Hr 773 1387 2456 3754 4485 5617 6210 6900 8639 1358 Equivalent Horsepower 25 50 75 100 125 150 175 200 250 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 is 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 all 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 and can be installed on two saddles. No expensive foundation or pit is required. No 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. Sizes range from 3,160 to 42,500 sq ft of steam radiation. Ratings of all these boilers conform to SB I. Write for Complete Catalog. 1359 Heating Systems Boilers, steel Re*. U. 8. Pat. OH. FitzgibbonsBoiler 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 Re*. U. S. Pat. OH. PRODUCTS--STEEL BOILER HEATING and POWER BOILERS for all fuels and all heating systems. Capacities to meet requirements of any building. Built and rated according to ASME and SBI Codes and "Hartford" inspected. "D" TYPE STEEL BOILER For mechanical firing with oil, gas or stoker in ratings from 2680 to 42,500 sq ft (steam), 4280 to 68,000 sq ft (water), 643 to 10,200 Btuh (1000's) EDR. 15 lbs Steam--30 lbs Water. For hand fired coal in ratings from 2200 to 35,000 sq ft (steam) 3520 to 56,000 sq ft (water), 528 to 8400 Btuh (1000'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 water. 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 Btuh (1000's) EDR. 15 lbs Steam --30 lbs Water. This compact, efficient Fitzgibbons boiler has the design advantages of complete water jacketing of all heating surfaces, including the rear furnace wall, thus elim inating usual rear dry-wall refractory lining and corresponding up-keep and repair expense. 1360 Fitzgibbons Boiler Company, Inc. "80" SERIES STEEL BOILER For smaller commercial buildings and large residences for oil, gas or anthracite coal firing in sizes from 1100 to 3000 sq ft (steam), 1760 to 4800 sq ft (water) and 264 to 720 Btuh (1000's)--all ratings SBI 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. Boners, steel `R.Z.U." JUNIOR STEEL BOILER Especially recommended for bituminous coal stoker firing, although excellent for oil, gas and anthracite firing as well. In sizes from 1100 to 3000 sq ft (steam), 1760 to 4800 sq ft (water) and 264 to 720 Btuh (1000's)--all ratings SBI net. Efficient firing with bituminous coal or other fuels is assured because of the ample tube area and diameter, 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) and 96 to 216 Btuh (1000's). "200" SERIES STEEL BOILER A steel boiler for the smallest homes with all the famous characteristics of Fitz gibbons design and construction. Low in fuel costs, high in heating efficiency with the Fitzgibbons TANKSAVER for tankless, year 'round domestic hot water. In sizes from 275 to 320 sq ft (steam), 440 and 510 (water), 66 and 77 Btuh (1000's). 1361 / ^ Heating Systems BoUers, steel The International Boiler Works Co. 500 Birch St., East Stroudsburg, Pa. Sales Offices in Principal Cities INTERNATIONAL Water Tube. Boilers are Supplying DEPENDABLE--LOW COST HEAT AND POWER for Apartmentbuildings. Office Buildings, Schools, Theatres^ Hotels, Greeiffious^, Industrial Plants. .. and Steam for Low and High Pressure Process Work, through out the Country. 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. .i INTERNATIONAL Water Tube Boilers are cutting fuel costs in thousands of heating installations. , Sizes and types for every requirement. 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 lb steam-30 lb water. Power Boilers 100-125rl50 psi. All Boilers ASME standard. Twin Section Healing Bader- Type C (Aleo {readable completely knockeddown-Type KD) For Oil, Gas, Stoker or hand fired Coal. ' Year round Domestic or Service hot water . . . from immersed copper coil, instantaneous or storage tank type. FOR FURTHER INFORMATION Induced Draft Power Bader-Type IDH For 8 page Catalog and complete specifi cations. WHITE TO THE INTERNATIONAL BOILER WORKS CO. East Stroudsburg, Pennsylvania 1362 Power Boiler-Type CR Heating Systems. Boilers, steel Johnston Brothers, Inc. ESTABLISHED 1854 Member. Fenysburg, Michigan 9* - O. S. Pot. Off. "PACKAGED" STEAM BOILER UNIT FULLY AUTOMATIC HEAVY OIL 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 500 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 507. ; 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 702. POWER PROCESS, HEATING. 25 to 300 hp and pressures 15 lb vto 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. 1363 1364 Kewanee. Boiler Cw?kati9n \ 400 and 800 Riveted Series for Heavy Duty OlvWofl oi AmmcAK Rapiatpb & /Uwlwd cowoiawbi , Kewanee, Illinois BRANCHES IN 64 PRINCIPAL CITIES Steel Heating and Power Boilers, Storage and Domestic Water Heaters FOR MORE THAN EIGHTY YEARS Kewanee Boilers have been outstanding for Long Life, Efficiency and Fuel Econ omy. Regardless of the type and size of building, or the fuel used, there is a Ke wanee just right for the job. They can be depended upon to produce the steam shown by their rated capacity, and even carry "overloads" of 50 per cent without any sacrifice of efficiency. Kewanee HEAVY DUTY RIVETED FIREBOX TYPES: 1380to42,500sq ft, 10 to 304 hp. Steam working pressures 100,125 and 150 lbs. Single-pass tubes for rear smoke outlet, two-pass for front smoke outlet. WELDED BOILERS: 3000 to 42,500 sq ft. Type "C" with rear smoke outlet; welded firebox two-pass for front smoke outlet. RESIDENCE STEEL BOIL ERS: 330 to 3000 so ft. Round and Square "R" with and without jackets. Boilers are built in strict accordance with Cottage 510 sq ft water boiler for oil-gas. ASME and SBI Codes. The Kewanee Water heating Coils either storage tank series include: or tankless. Boiler No.. SBI Rating Steam, Coal......................... Sq Ft Horsepower............................................. Hp SBI Rating Oil, Gas, Stoker..................Sq Ft Horsepower................................................... Hp Width and Length.......................... In. x Ft In. Overall Height Shell........... . . ...................In. Height of Water Line.................................... In. 576 3500 25 4250 30 42x8-7 80H 73 577 578 579 4000 4500 5000 29 32 36 4860 5470 6080 35 39 44 42x9-6* 48x8-lH 48x9-8 80M 88H 88H 73 76 76 580 581 480 481 6000 7000 43 50 7290 8500 52 61 84x9-21 54x10-6 94M 83 MX 83 583 584 585 587 588 589 590 483 484 485 487 490 10000 12500 15000 17500 20000 25000 30000 35000 72 89 107 125 143 179 214 250 12150 15180 18220 21250 24290 30360 36430 42500 87 , 109 130 152 174 217 261 304 60x12-9 66x12-10 66x14-9: 72x14-9 78x14-9 78x17-7* 84x17-9* 84x20-0* 102 108 108 114 116 116 126 i 126 97H 100 100 108 108 Two-Pass Tubular SO to 180 HP Six sizes for power or industrial process steam, for all fuels. 125 and 150 lbs W.P. All joints are fusion welded. Xray checked and stress relieved. Quick steaming unit, compact yet extra rugged. Metal casing is designed for refractory lined firebox. KEWANEE HI-TEST BOILER Boiler Number............................. HT 50 HT 60 HT 75 HT 100 HT 125 HT 150 Horsepower, Hand-fired............. 50 60 75 100 ' 125 150 Mech.-fired............ 60 72 90 120 150 180 Founds steam per hour, Hand-fired............................. 1730 Mech.-fired................................. 2070 2070 2470 2590 3110 3450 4140 4330 5180 5180 6210 Fur. vol. above grates. .cu. ft.. 72 90 105 140 181 213 Cylinder diameter--fronts in.... 42 42 42 48 54 --rear, m....... 66 66 72 78 84 54 84 Boiler length overall, ft.ln........ 12-5 13-5 14-3 15-5 16-2 Boiler height, floor to top in.... 107 113 116 126 142 Water line height, in................... 95 101 104 111 124 18-6 142 124 & ft CO 'g ~4 . 1365 KEWANEE SCOTCH MARINE TYPES High and Low Pressure Boilers ft ft ft ft ft to O SPECIFICATIONS-- Scottle Jr. 125 lbs. S.W.P. M-8100 Low Pressure SCOTTIE JR. for 6 to 36 hp is an ideal unit for producing high boiler No............................................... Ratings--Mechanical-Fired......... Hp --Lbs of Steam per hr......... Ratings--Hand-Fired................... Hp --Lbs of Steam per hr......... Shell Diameter................................In. Length Overall, Oil-Gas............... In. Height Overall 8hell......................In. Height of Water Line.................... In. HM 6 7 242 6 207 42 82H 54H 46H HM 9 12 410 9.9 342 48 8$ 53 HM15 18 620 15 520 48 105 62 53 HM20 24 830 20 660 48 W 53 HM25 80 1050 25 865 54 127 Sg HM30 86 1240 80 1050 54 144 80 SPECIFICATIONS--HM SCOT SERIES--125-150 lbs S.W.P. pressure steam at low cost for small loads. Economical to operate with oil, gas or coal at 125 lbs steam working pressure. HM SCOT for 52 to 304 HP has full length corrugated furnace and heavy gage tubes completely surrounded by water. Burns oil or gas. Generates maximum heat from the fuel. 125 and 150 lbs working pressure. M-8100 is low in first cost and economical to install. Low waterline makes it ideal where headroom is important. En tirely self-contained with return firetubes ana tubular fur nace. ` " ' Boiler Number.................................................. Rating, Steam Radiation............................... HoreeDower.................................................... Thousands of Btu per Hour......................... ,, HM-52 HM-61 HM-74 HM-87 7290 8500 10330 12150 1750 2040 2479 HM-109 HM-130 HM-152 HM-174 15180 18220 21250 24290 HM-217 HM-261 HM-304 30360 36430 42500 7286 8743 10200 Boiler Length..................................................... Boiler Height, Floor to top of Shell......... Water Line Height......................;.............. 10-6 U-8M 73 73 62 62 12-0 79 6SH 13-8 79 65M 14-10 85 69H 15-3 91)i na 17-3 m 73M 84 16-4 97K 77M 90 17--6 103H 82}* 96 18-6 109H 87H 102 18-6 115M 92k SPECIFICATIONS--LOW PRESSURE SCOTCH MARINE TYPE BOILER Boiler No- M-8178 *SBI Rating, Steam Rad............................... Sq Ft 5470 Btu per hr..............................................1000'a 1313 SBI Net Ratiog,Steam Rad......................Sq Ft 4500 Btu oer hr............................................. 1000's 1080 Furnace Volume (SBI min).................... . .Cu Ft 39.1 Shell Diameter........................................................In. 54 Length Overall................................................Ft In. Height Overall Shell.............................................. In. H$M Height of Water Line...................................... .in. * Water radiation 60 per cent more than steam. M-8179 6080 1459 5000 1200 43.5 54 9-11 88 M-8180 7290 1750 6000 1440 52.1 60 9-4 72X 59 M-8181 8500 2040 7000 10-5H 72H 59 M-8182 10330 2479 8500 2040 73.8 66 10-7 7SH 64 M-8183 12150 2916 10000 2400 64 M-8184 15180 3643 12500 3000 108.5 72 12-6 M-81S5 18220 4378 15000 3600 130.2 72 14-8 84k 69H M-8186 21250 5100 17600 4200 151.8 78 14-10H 90k 7\H M-8187 24290 5830 20000 4800 173.5 78 16-6 99}* 71k M-818S 30360 7286 25000 6000 216.9 84 18-2 97 74k M-8189 36430 8743 30000 7200 260.3 90 18-8 103 80 M-8190 42500 10200 35000 8400 303.6 96 18-0** 109 84 &ft ft I' to Kewanee Boiler Corp. rr if KEWANEE TYPE "C" HI-FIREBOX with Corrugated Crown Sheet Because of its ability to produce large amounts of steam quickly, while requiring a minimum of floor space, Kewanee Welded Type "C" has become the choice of engineers for heat ing larger buildings efficiently and at low cost. KEWANEE "5000" Series Welded The Corrugated Crown Sheet, developed by Kewanee, provides many advantages. The massive corrugations, made one-at- a-time, retain the same metal thickness throughout, adds strength, and provides additional heating surface which comes in contact with the hottest part of the fire. This up-draft firebox boiler burns any fuel. 15 sizes for low pressure heating, features increased heating surface, steam space, furnace volume and water content, yet takes up less room than similarly con structed boilers. SPECIFICATIONS--TYPE "C" HI-FIREBOX WELDED BOILER 7L70 Series & 27L70 Series . Boiler No. Oil, Gas, Stoker:..................... i 7L75 i 7L76 i 7L77 1116 1L19 1L6t> | VLSI 7L8Z 7L83 7UT4 | 7L85 7L86 7L87 | 7LS8 7L89 7L9Q SB1 Rating Steam.......................... Sq Ft SBI NetRating...............................Sq Ft Width x Length......................In. x Ft In Overall Height Shell........................... In. Height of Water Line.......................... In. 3650 4250 1 4860 5470 3000 3500 4000 4500 36x6-10) 36x7-9 42x7-10) 42x8-61 84 84 88M 88)4 . 75: 75 76H 7m 6080 7290 6000 6000 42x9-2 48x9-41 8814 92)4 76J4 79M 8500 7000 48x10-7 88 10330 8500 54x9-11 106 91 12150 15180 18220 21250 24290 30360 36430 42500 10000 .12500 15000 17500' 20000 25000 30000 35000 54x11-2) 50x11-6) 56x12-3) 72x12-1) 72x13-4) 78x14-9) 34x14-2) 84x16-11) 106 115)4 120)4 130)4 130)4 138 162)4 192)4 91 100)4 103 . 113 113 119 141H 141)4 Boiler No. Hand-fired Coal.................. 27L75 27L76 27L77 tills 27L79 27L80 27L81 27L82 27L83 27L84 27L85 27L86' 27L87 27L88 27L89 27L90 SBI Rating Steam...........................Sq Ft 3000 3500 4000 SBI Net Ratine............................... Sq Ft 2500 2920 3330 4500 5000 6000 3750 4170 5000 7000 6830 8500 10000 12500 15000 17500 20000 25000 30000 /' 35000 7080 8330 10420 12500 14580 16670 20830 25000.' 29170 SPECIFICATIONS--WELDED FIREBOX B OILER , "5000" Series & "6000" Series m Downdraft............................................ 5077 6077 5573 6078 5079 6079 5080. 5081 6080 6081 5082 6082 5083 6063 5084 6084 5085 6085 5086 6086 5087 6087 5088 6088 5089 6089 5U9U 6090 SBI Rating Steam, Coal..........................8q Ft SBI Net Rating.........................................Sq Ft 3500 2920 4000 3330 4500 3750 5000 4170 6000 7000 5000 5830 SBI Rating Steam: `,, Oil, Gas, Stoker......................................q Ft SBI Net Rating.........................................Sq Ft Width x Length...............................In. x Ft In. Overall Height................................................ In. 4250 3500 '42x7-3 81 70 4860 4000 42x8-2 81 70 5470 4500 42x8-11 81 70 6080 5000 42x9--1C 81 70 7290 6000 48x9-9 86)4 73)4 8500 7000 48x11-1 86)4 73)4 Rated Capacity for Water Boiler iB 60 per cent greater than Capacity for Steam toiler, ' 8500 10000 12500 15000 17500 20000 25000 30000 35000 7080 8330 10420 12500 14580 16670 20830 25000 29170 10330 8500 54x11- 92)4 77H 12150 15180 18220 21250 24290 30360 36430 ,42500 10000 12500 15000 17500 20000 25000 30000 '35000 54x12-1 60xl3-2j 60x15-3 66x14-51 66xl6-OJ 72x16-84 78x17-54 78x19-8) 92)4 100)4 100)4 105 105 111 117 117 77)4 84 84 86 86 93 99 96 Table for two senea of Boilers lists maximum dimensions only. '' 1366 Heating Systems Boners, steel Kewanee'^BoileijCorp.________________ !367 KEWANEE TYPE "R" RESIDENCE BOILERS Built of the same husky steel plate and by the same skilled workmen as Kewanee's famous larger boilers, Type "R" Welded Series provide all the advantages of their well-known Dependability and Fuel Economy to fully meet heating requirements " ' buildings. Any Type "R" can be converted from mechanical lo nana-nring or oacg again without making any change in the boiler proper. Water heating coils, tank or tankless models, can be installed at any time at small extra cost SQUARE-HEAT Type "R" is built ip 8 sizes from 740 to 3000 sq ft steam, or 1180 to 3970 sq ft of water radiation. Can be furnished with attractive jacket. ROUND Type "R" comes in 4 sizes ranging from 330 to 900 sq ft steam, or 530 to 1440 sq ft water. Available with square, or insulated round jacket. COTTAGE vertical tube boiler for hot water heating is built for oil or gas firing only; 77,000 Btu or 610 sq ft wa ter radiation. Compact two-tone green jacket occupies minimum space. KEWANEE STORAGE WATER HEATERS Ample hot water for steady service and sudden demands, using live or exhaust steam. 15 standard coil elements in 29 standard size storage tanks. Capacities 95 to 2240 gph. TABASCO WATER HEATERS Built of extra heavy steel plate, allwelded, for long life. 5 sizes to heat 165-700 gal raised 50 deg per hour. Burns any fuel. 100 lbs working pres sure. Cottage New KEWANEE COTTAGE BOILER SPECIFICATIONS Square-Heat Round MR" Cottage Boiler No............................................................... 3R1 3R2 3R3 3R4 3R5 3R6 3R7 Net Load Steam, Haodfired.................. Sq Ft Water........................................................SqFt Btu per Hour............................................ 1000's Net Load Steam, Mechanical...................Sq Ft Water........................................................SqFt Btu per Hour............................................1000's Heating Surface........................................ SqFt 740 1180 178 900 1440 216 63 910 1460 218 1100 1760 264 65 1080 1720 261 1300 2080 312 77 1230 1970 296 1500 2400 360 88 MAO 2370 366 1A00 2AA0 432 106 1810 2140 2480 330 2890 3430 3670 530 434 514 ,, 70 2200 2600 8000 400 3520 4160 4800 640 52A 624 720 66 129 153 177 24 670 910 137 700 900 1120 1440 610 168 216 77 41 53 19 Width and Length............................... In z In. Overall Height from Floor.......................... In. 30x30f30x36).30x42) 80x48) 34x42) 84x50) 84x58 65 65 M 65 72U 72)4 72U \MH^h^fWatwLine^^^^^j^^Jn: m m "M 62)4 28 81 31 20 4578l604M91604H9 m A Direct-Fired Domestic WATER HEATER Provides plenty of hot water dependably and ec onomically, for working pressures of 100 lbs; am ply strong to safely with stand the high water pressures carried in most city mains. 140 gal raised 100 deg per hour. Handsome two-tone in sulated jacket. Burns oil or gas only. Heating Systems Boners sted 5 v Heating Systems Boilers, steel THE TITUSVILLE IRON WORKS CO. TITUSVILLE, PENNSYLVANIA OF STRUTHERS WELLS CORPORATION DIVISION Designers and Manufacturers of A.S.M.L BOILERS...since 1860 Dependable CODE 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 psig. 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 Desiynaiion SOD Titusville Scotch Marine Heating Boilers built in 19 sizes ranging from 129 square feet to 2500 square feet heating surface, and maximum steam working pressure 15 psig. Type Designation Wee Scot to SO HPt SP above SO UP Titusville Scotch Marine Power Boiler built in 13 sizes ranging from 97 squar8 feet to 3000 square feet heating Burfac e Pressures 125 psig and 150 psig. e- Type Designation Ticotherm Titusville Ticotherm Steam Generators built in 13 sizes ranging from 1000 square feet to 5000 square feet heating surface. Pressures 160 psig, 200 psig, 250 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 psig, 160 200 psig, 250 psig and higher. Descriptive technical literature is available on request. 1368 Heating Systems Stem Generators Vapor Heating Corporation 1450 Railway Exchange, Chicago 14, Illinois New York e St. Paul Cleveland St. Louis Denver Washington Philadelphia San Francisco Portland Los Angeles e Jacksonville Houston SIGNIFICANT FEATURES OF VAPOR-CLARKSON STEAM GENERATING UNITS Full steam pressures within 2 minutes, from cold start. To start, press one button. Operating pressures can be regulated between 75 and 300 lbs per sq in. Minimum space required- exceptionally light weight (see table below). Construction conforms to A.S.M.E. Code and is Hartford Steam Boiler In spection and Insurance Co. inspected. Fuel and air intakes are above the zone of inflammable gases. No fire-tubes or grates; no crown-sheet or fire-box. No headers or drums; no water level to watch, hence no water level gage. Easy and economical to operate and maintain. High efficiency--beyond rated capacities. Automatic ignition; forced circulation. A FEW SPECIFIC USES On Diesel locomotives for passenger train heating. Pile Driving . . . Asphalt Plants. Concrete Plants and Concrete Curing. Paint stripping of all kinds. Emergency heating during repairs to stationary boilers. Oil field drilling Drying, in hospitals or laundries. Cleaning . . . Heating marine craft. Sterilizing of all kinds. Cooking and hot water for field camps. Road construction--drying sand, thawing culverts. Vulcanizing process and other process work. . Wherever instant pressure steam is required. TYPE OF UNIT 4951 4954 4616 4625 4630 4635 4740 4612 DATA ON VAPOR-CLARKSON STEAM GENERATORS HORSE POWER (212 F) 18 35 65 105 125 135 165 - 450 POUNDS STEAM PER HOUR (212 F) 640 1300 2070 3450 4000 4530 5200 15,500 DIMENSIONS (Inches) Length 39M 72 MX 68 80 80 73 96 Width 28 43 45 43 60K 60R 50 96 1369 Height 47 60H 67 73 72 72 79M 96 WEIGHT (Dry) Pound! 800 1325 2240 3000 3900 4500 5900 18,500 MOTOR RATING Horaepower 1H 2 3 5 5 5.4 7M / ' Heating Systems BoUer compounds The Vinco Company, Inc. 47 West 63 Street New York 23, N. Y. VINCO 5nEST0B* Sating srsitH Boiler Cleaner S and 5 lb. cans Oniy o clean boiler can be an efficient boiler. A clean boiler means saving fuel, as well as safeguarding boiler metal. A positively harmless Insoluble powder cleaner for new, re modeled and old heating systems. A unique, scientifically pro cessed compound on a special formula not to be confused with other powder boiler cleaners. . . What Vinco Boiler Cleaner Does Vinco removes oil, grease, scale, rust and dirt from the in ternal surfaces and from the boiler water- without the labor, expense, and uncertain results of blowing boilers over the top or of wasting returns. . By this thorough cleaning Vinco prevents or cures foaming, priming, surging, and slow steaming. How Vinco Boiler Cleaner Works Each minute grain of Vinco powder adsorbs several times its own weight of oil, grease, rust and dirt. These larger grains of adsorbed impurities then settle and are drained through the , bottom according to directions on each can. Vinco Guarantees 1. Vinco contains no potash, lye, soda of any kind; oil, acid, ' or other harmful ingredients. 2. Purchase price is refunded if results are not as claimed when Vinco has been used according to directions. VINCO RUST PREVENTER When used after Vinco Boiler Cleaner has removed oil, grease, rust, scale and dirt, it will add and keep the rust inhibiting factors at the optimal con stant for a year or more. (Test kit be low has complete instructions and chart.) if! ife msm VINCO FIELD TEST KIT No. 10 for Testing and Treating Heating Boiler Waters V- V1 The kit enables the layman to make simple, rapid tests to diagnose and prescribe correct treatment of boiler waters right on the job. - A new time saving method that permits valid conclusions I heretofore requiring complicated and often lengthy laboratory analysis and technique. Each kit has sufficient material for complete tests on 100 jobs. Vinco Field Test Kit No. io Refills cost about 2 cents for testing each job. 1370 The Vinco Company, Inc. Heating Systems Boner compounds SPECIFICATIONS FOR COMPLETE VINCO TREATMENT OF NEW OR REMODELED STEAM, VAPOR, OR HOT WATER SYSTEMS Do not use as a cleaning agent soda or any alkali, vinegar, or any acid. Use Vinco. 1. AFTER THE SYSTEM IS TESTED AND TIGHT, USE THE PROPER QUANTITY OF VINCO LISTED. After this first clean-out of any new or remodeled heating system, Vinco Boiler Cleaner need be used only if more piping, radiation, or another boiler is added to the original installation, or if the system is folded by unwise cleaning or leak-sealing experiments. 2. After using Vinco Boiler Cleaner, Vinco Field Test Kit should be used to determine and apply the proper quantity of Vinco Rust Preventer. Vinco Rust Preventer should be applied annually or whenever the boiler water is drained for necessary repairs to the system. SPECIFICATION FOR OLD HEATING SYSTEMS THAT DO NOT PERFORM PROPERLY Diagnose and treat according to Vinco Field Test Kit. If a test kit is not avail able, consult table of quantities on thiB page and follow directions on Vinco cans. SPECIFICATION FOR HOT WATER SYSTEMS If maintained below 200 F, use half quantities listed for treatment of steam systems to remove impurities. If main tained at approximately 200 F or above, use full quantities. Then use test kit to determine proper quantity of Vinco Rust Preventer. CONSULT THIS TABLE FOR NEW AND REMODELED HEATING SYSTEMS AND When a Vinco Field Test Kit No. 10 is not available if cleaning old heating systems. QUANTITIES OF VINCO (IN POUNDS) RE ..........QUIRED FOR HEATING SYSTEMS (Note that quantities are based on actual in stalled radiation, not on boiler capacity.) For Steam'or Vapor Systems, to prevent or cure priming or foaming. Sq Ft of Radiation Also for Hot Water Heating Systems Main tained at ap Annually, to remove rust scale, dirt and for Hot Water Systems below 200 F. prox. 200 F or above. . up to 350.......... 351 " GOO.......... 601 44 1100.......... 1101 " .1400.......... 1401 44 1800.......... 1801 44 2100.......... 2101 2700.......... 2701 " 3100.......... 3101 44 3700.......... 3701 " 4200.......... 4201 " 4600.......... 4601 " 5000.......... 5001 " 5300.......... 5301 " 5600.......... 5601 " 5900.......... 5901 " 6200.......... 6201 " 6500.......... 6501 " 6800.......... 6801 " 7100.......... 7101 44 7400.......... 7401 44 7700.......... 7701 44 8000.......... 8001 44 8300.......... 8301 44 8600.......... 8601 44 8900.......... 8901 44 9200.......... 9201 44 9500.......... 9501 44 9800.......... 9801 44 10100*......... 3 5 8 10 13 . 15 18 20 23 26 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 IH 2H 4 5 6M 7H .9 10 UH 13 15 15H 16 16M 17 17M 18 18H 19 19M 20 20H 21 21H 22 22M ' 23 23M . Above 10100 sq ft- use an additional pound Vinco for each additional 300 sq ft of actual installed radia tion. Seal-Off--1 lb. cane SO and 100 lb. drums Liquid Boiler Seal 1 qt. cans only REMOVE SOOT WITH VINCO SOOTOFF SEVERAL TIMES A YEAR Safely and thoroughly removes the in sulating blanket of soot on fire pot, flues and chimney. It also insures against ex ternal corrosion (caused by dampness and soot forming sulfuric acid during sum mer layoff.) No dangerous chemicals. VINCO SUPERFINE LIQUID BOILER SEAL ^different liquid seal. Unique in that it does not induce priming and foaming, l ,haa no unple^sant smell. Makes lasting repairs of boiler and heating system leaks. Fine to tighten up new jobs. Directions simple. _ Quantities--Steam and Vapor Systems--Use 1 quart Vinco Liquid Boiler Seal to each 6 sq ft grate area. Hot Water Systems--Use 2 quarts Vinco Liquid Boiler Beal to each 6 sq ft grate area. - .. 1371 Heating Systems BoUer Feeders McDonnell & Miller, Inc. Safety Devices for Steam and Hot Water Heating Boilers . . . Liquid Level Controls ' 3500 North Spaulding Ave., Chicago -18,. Illinois The McDonnell line consists of (1) boiler water feeders, low water fuel cut offs and combined feeders and cut-offs for low pressure steam boilers of all sizes and types, hand-fired or automatically fired; (2) pump controls, low water fuel cut-offs and low water alarms for steam boilers of any size or type with pressures up to ISO lbs; (3) safety relief valves (Btu-rated) for hot water heating boilers and domestic hot water heaters; boiler water feeders and low water fuel cut-offs for hot water heating boilers; (4) make up water feeders for receiving tanks and other liquid level controls for special applications; (5) water level controls for humidity pans of warm air furnaces. The selection of controls for usual applications is shown in the following service recommendation. Most of these products are described in the following three pages. Service Reci (1) STEAM BOILERS Boiler Size Maximum Steam Pressure McDonnell product to use HAND FIRED JOBS Up to 5000 sq ft Above 5000 sq ft 25 lbs 35 lbs No. 47 Boiler Water Feeder No. 51 Boiler Water Feeder Any size 75 lbs No. 53 Boiler Water Feeder ' AUTOMATICALLY FIRED JOBS Boiler Water Feeder--Low Water Cut-off Combinations Up to 5000 sq ft 25 lbs No. 47-2 Feeder Cut-off Combination Above 5000 sq ft . 35 lbs No. 51-2 Feeder Cut-off Combination . Any size Any size Any size 75 lbs No. 53-2 Feeder Cut-off Combination LOW WATER FUEL CUT-OFFS 20 lbs No. 67 Low Water Fuel Cut-off 50 lbs (Steam or water) No. 63 Low Water Fuel Cut-off Any size 150 lbs No. 150 or No. 157 Low Water Fuel Cut-off (Industrial or Process boilers--Specific recommendations on receipt of ^ complete data.) (2) HOT WATER HEATING BOILERS .-j Opening Pressure 30 Ibe. 30 lbs. 30 lbs. Btu. per Hour Capacity 242,900 496,700 769,400 McDonnell Product to use No. 33 Safety Relief Valve The 233 Safety Relief Valve Assembly The 333 Safety Relief Valve Assembly (3) DOMESTIC HOT WATER TANKS AND HEATERS Opening Pressure Btu per Hour Capacity McDonnell Product to use 45 pounds 75 pounds 100 pounds 125 pounds 150 pounds 321,300 308.700 423.900 513.900 605.700 No. 3345 Safety Relief Valve No. 3375 Safety Relief Valve No. 33100 Safety Relief Valve No. 33125 Safety Relief Valve No. 33150 Safety Relief Valve 1372 McDonnell & Miller, Inc. Heating Systems Boiler Feeders, Safety Petices Boiler water feeders, feeder-cut-off combinations, and low water cut-offs ... for low and moderate pressure steam boilers McDonnell No. 47-S for heating boilers under 6000 sq ft capacity. Maximum steam pressure, 85 lbs. McDonnell No. 61-8 for heating boilers over 6000 sq ft capacity. Maximum steam pressure, 36 lbs. McDonnell No. 47-2, shown installed above, maintains a safe water level in boiler by feeding water whenever neces sary. If emergencies such as priming or foaming permit water to fall to J in. in gauge glass, cut-off switch cuts cur rent to burner until emergency has passed. Has "Quick-Hook-Up" for fast, accurate installation right in gauge glass tappings; "cool" feed valve; extra-deep sediment chamber; .4 SALE-approved blow-off valve. Also available for hand fired boilers without No. 2 switch, as No. 47 Feeder. McDonnell No. 51-2, shown installed above, is same as No. 47-2 described at left, except it has greater feeding capac ity for larger boilers, and is installed with 1 in. equalizing pipes instead of "Quick-Hook-Up." Also available for hand fired boilers without No. 2 switch, as No. 51 Feeder. For boilers operating at higher pressures, from 35 to 75 lbs, use McDonnell No. 53-2 (or No. 53, without switch.) McDonnell No. 67 Low Water Cut-off For automatically fired steam boilers of any size Maximum steam pressure, 20 lbs. Has the McDonnell "Quick-Hook-Up" for quick, easy and trouble-proof installation in gauge glass tappings; deep sedi ment chamber with large quick-opening blow-off; packless, non-binding construction; adjustable terminal box to make wiring neat and easy; dependable snap-action twin switches. One switch can be used to sound low water alarm, or control McDonnell No. 101 Electric Water Feeder described below. Second switch cuts current to burner if water level drops to 34 in. in gauge glass. McDonnell No. 101 Electric Boiler Water Feeder For boilers up to 5000 sq ft capacity For use with No. 67 Low Water Cut-off or with McDonnell "built-in" Low Water Cut-offs which are standard equipment on many modern heating boilers. It converts the cut-off into a feeder cut-off combination as described at top of this page. 1373 McDonnell & Miller, Inc. Heating Systems i^coniSis 'McDonnell Pump Control, Low Water Fuel Cut-off and Alarm Switch ... for steam boilers of any size; maximum steam pressure, ISO lbs. The McDonnell No. 150 Pump Control, Cut-off and Alarm switch (and its equiv alent, No. 157) is built down to the last detail to stand the gaff of high pressure and temperature. It is equipped with two switches. One closes on small float drop to control electric boiler feed pump, or electric valve in line to steam pump. Second operates on greater drop to stop burner and complete low water alarm circuit. Underwriters' Laboratories ap proved. 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 greatly sim- . plifles installation, assures ideal repro duction of boiler water level in float chamber, and provides effective direct blow-down. No. 157 has automatic re set; for manual reset order No. 157-M. Operation of No. 150 or 157 Typical hook-up of the McDonnell No. 150 is shown at right. When water level- drops, No. 150 starts pump and then stops it when normal level is restored. If emergency occurs, cut-off switch stops burner; terminals for low water alarm are also provided. This method holds boiler water level within the close limits necessary to attain not only safety, but also highest steam ing efficiency. This has obvious advan tages over the ordinary method of simply returning condensate whenever a certain quantity has accumulated in receiver. Note McDonnell No. 27 make-up water feeder on receiver to maintain minimum water supply. . Drawings are available for all operat ing conditions--including two or more . boilers supplied by one pump. McDonnell No. 63 Low Water Cut-off for automatically fired hot water heating boilers. In any hot water heating system there is a possibility of low water after a prolonged opening of an adequate relief valve as the result of some emergency condition. The protection against this, in automatically fired boilers, is a low water fuel cut-off, and for some time heating engineers have been using the McDonnell No. 150 to provide this protection because our low pressure low water cut-off was not rated for the higher pressures of hot water boilers. As a result the No. 63 Low Water Cut-off has been de veloped for pressures up to 50 lbs. It provides an equally de pendable low water cut-off for hot water boilers at a more moderate price than that of the No. 150 which must be designed for higher pressures. The McDonnell No. 63 is also used on steam boilers where hook-up with 1 in. equalizing pipes is de sired. No* 63 1374 McDonnell & Miller, Inc. Heating Systems Boiler Water Level Controls McDonnell No. 33 Series Safety Relief Valves McDonnell Safety Relief Valves are built to comply with cur rent ASME Boiler Code, and have been tested and rated by the National Board of Boiler and Pressure Vessel Inspectors. The certified rating appears on the nameplate attached to each valve. The No. 33 Series offers the ultimate in safety in guarding boilers and water systems against the dangers of over-pressure. They have low discharge rate which handles normal thermal expansion easily, and high rate for emergency conditions. For Hot Water Heating Boilers No. S3 tss Assembly 333 Assembly McDon nell No. 33 Opening Pressure 30 lbs. Btu/hr Capacity Valve McDon nell No. Opening Pressure Btu/hr Capacity Valve McDon nell No. Opening Pressure Btu/hr Capacity 242,900 A B 33 3333 30 lbs. 33 lbs. 242,900 253,800 A B C 33 3333 3336 30 lbs. 33 lbs. 36 lbs. 242,900 253,800 272.700 Total Capacity Btu/hr 496,700 ' Total Capacity Btu/hr 769,400 For Domestic Hot Water Tanks and Heaters Valve No. 3345 3375 33100 33125 33150 Opening Pressure 45 lbs. 75 lbs. 100 lbs. 125 lbs. 150 lbs. Btu Capacity . 321,300 308,700 423,900 513,900 605,700 . Inlet Pipe Size 3_/r 3<r r i' r Outlet Pipe Size 1' 1* \* 1' . McDonnell No. 201 Temperature Relief Valve For Hot Water Tanks and Heaters A.O.A. Tested, Rated and Listed Heat Input 1,200,000 Btu/hr. Utilizes the well-known Vematherm thermostatic element, which combines high accuracy, durability and ideal operating characteristics. Opens at 188F, reaches full discharge capacity at 208F. McDonnell design places this element nght in the flow of hot water to fixtures, where it rapidly and more uni formly responds to variations in temperature. Suitable for operating pressures to 125 lbs. McDonnell No. 33 Safety Relief Valve and No. 247 Feeder for hot water heating plants with' boiler and radiation on same level. The drawing illustrates how the MeDonnell No. 33 and No. 247 team up to provide 1boitLh effic__i_e__nAt -o---p----e---r--a-Xt*ion anJd .p..ro- tection for "same-level" systems. In this type of plant there is always a possi bility of separation of the boiler from the connected load unless a means'of main taining a proper level is provided. The No. 247 water feeder does this by keeping the water level above the highest, point in the main. Protection from excess pressure is provided by the No. 33 Safety Relief Valve for all boilers up to 242,900 Btu output. When the boiler is auto- matically fired the No. 247 can be used with low water fuel cut-off switch (No. e\2A<4s7n-x2). Write for Literature--Condensed Catalog covering more popu lar McDonnell Products . . . Supplemental Catalog covering feeders, cut-offs and switches for all operating conditions . . . and Sample Specification Sheets. 1375 Heating Systems {Pipe) . Fiuid'd Fluid Systems, Inc. 1881 DIXWEll AVE. NEW HAVEN 14, CONN. Fluid Systems, Inc. and Thermal Electric are trade marks registered U. S. Pat. Off. and Patent #2,224,403. FUNCTIONAL SIMPLICITY FOR FUEL HANDLING SYSTEMS The common sense of fuel transport is permitted--for any make of burner--by the Thermal Electric Method, developed and engineered by Fluid Systems, Inc. ' The temperature of the fuel is elevated throughout the pipe system by impressing low voltage on the pipe wall. Volt age does not exceed 20 volts and the pipe is the current conduc- tor. Pipe heat losses are exactly offset and heat is generated at 100 per cent efficiency--at the very place where friction loss ' originates. A temperature of 120 F is maintained thermostati cally, under all conditions of flow or non-flow. At that tem perature any # 6 fuel of U. S. Specification assumes the viscos- # ity of light, free-flowing oil--and acts like it. - ' J '' There is no magic, no hidden play. Just good, plain, un decorated, simple hydraulic engineering. . Our intensive specialization has yielded valuable knowl edge about residual fuels and their handling. It is freely available--from design to final operation.- Ask for "The Com mon Sense of Fuel Transport." Write to:-- FLUID SYSTEMS, INC. 1881 Dlxwell Ave., New Haven, Conn. 1376 Heating Systems (Pipe) Bunker Oil and Viscous Fluid Fluid Systems, Inc. 1881 DIXWEll AVE. NEW HAVEN 14, CONN. Fluid Systems, Inc. and Thermal Electric are trade marks registered U. S. Pat. Off. and Patent #2,224,403. HYDRAULIC ENGINEERING by FLUID SYSTEMS, INC. The Thermal Electric Method of han dling residual fuel for oil burning sys tems is an accomplishment in functional simplicity. Unheated underground storage is now made possible by the simple Thermal Electric Tank Unit. The hazards and costs of steam or water coils are removed - . . fuel stratification eliminated. Smaller pipe sizes. Remote pump(s) eliminated for a majority of installations. Fluid Systems, Inc. occupies a unique position in the oil burner industry. Full responsibility for the fuel handling sys tem is lifted from the shoulders of the Specifying Engineer and the Installer-- and then guaranteed by Fluid Systems. OWCMIFTOBHU*W4OTMEiltG&BAAUAMSlGNPEtUtMSMEPNI 1377 Heating Systems Burners. Gas Sonner Burner Company Designers and Manufacturers of Gas Conversion Burners and Unit Heaters Offices and Factories: Winfield/Kansas , Type L-49 Heat Machine Type LV 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-49 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 300,000 Btu/hr. See Cat. 49-L-2R. 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. 49-LV-l. Special assemblies are available if required. 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. TYPETR^GAS BURNER FOR^SCOTCH MARINE BOILERS, brickset boilers, and other horizontal flame applications. Standard-Assemblies from 480,000 to 5,760,000 fBtu/hr described in Cat. 51-R-2. Special assemblies are also available if required. Unit Heater 1378 Type R SONNER Burner Heating Systems Burners, gs The Webster Engineering Company 115 South Frisco St., P.O. Box 2168 Tulsa, Oklahoma Division of SURFACE COMBUSTION CORPORATION, TOLEDO, OHIO Low Pressure Gas and Standby Oil. Consisting of a multiplicity of full venturi mixers with flame retention noz zles assembled in a metal casing com plete with pilot and louvre, the WEB STER KINETIC burner is presented as the latest addition to the Webster line of firing equipment. It may be used with natural, mixed and liquefied petroleum Series F600 and Series 650 Verti cal Gas Burners for Heating and Power Boilers. ., Series 340 Gas Burners for Vertical Boilers. ' Being a multiple head assembly, the WEBSTER KINETIC burner can be supplied in any size or shape. The firing Series VI and Webster Rectilinear High Pressure Inspirators for Boilers, Kilns, Stills, Dryers, etc. of Scotch Marine boilers with extremely low pressure gas without noise, vibration or electrical power and with minimum furnace draft was the sole objective when the WEBSTER KINETIC burner Series 200 and Series R Combination Gas and Oil Burners for Power Boilers. was developed. When design conditions preclude the use of a vertical burner in a steel firebox or sectional boiler, the Sales and Service In all principal WEBSTER KINETIC burner is highly cities. . recommended as the next best gas appli 3 cation. Trade Mark 1379 t Heating Systems Burners, gb and oa John Zink Company 4401 S. Peoria -- Tulsa, Okla. 342 Madison Ave. -- New York, N. Y. Heating Systems Burners. Gas and oa John Zink Company 4401 S. Peoria -- Tulsa, Okla. 342 Madison Ave. -- New York, N. Y. SERIES STV GAS BURNER Ideal for heating boiler installations. From one head to fifty heads. Quiet, effi cient and economical operation. Write for literature. SERIES VR VERTICAL GASBURNER 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 m boilers .having low draft and small combustion space. Write for literature. , .f ,J; f(' / to V- \ . ' . CBM-S \ J SERIES CBM-S COMBINATION GAS AND OIL BURNER The John Zink Series CBM-S Register Type Burner for either atmospheric or forced draft operation is specifically designed to provide short flame and high C02 when firing either with oil or with gas at 2 os to 3 lb. Burners for Process industries, High Pressure Steam Generation, Direct Fired Air Heaters, for applications requiring heated streams of mixed flue gas and air. 1380 . FLOOR FURNACES A size for every home heating requirement. Small grille--fool proof--simple to operate--AGA approved--sturdy, construction. Sizes 30,000 ; 35,000 ; 50,000 and 85,000 Btu input. Write for literature. NEW SUSPENDED UNIT HEATER (Series U 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. 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. 1381 Heating Systems Burners, on Ace Engineering Company 1435 West 15th StT, Chicago 8, 111. "Custom Engineered Oil Burning Systems Since 1931" The Ace Uniflow oil burner is built in ten sizes to burn all grades of fuel oil. The oil pump is available either as an integral part of the burner or as a sepa rate unit, depending upon the job re quirements. Standard models include both belt and direct drive and for opera tion with all electrical current character istics. The Ace oil burner features as standard equipment the patented Ace Uniflow valve, which permits constant uniform flow and flame regardless of oil tempera ture or viscosity. Approved by Underwriters' Labora tories, Inc., New York Board of Stand ards & Appeals and the States of Massa chusetts and Connecticut, these burners are designed to oil fire commercial and industrial boilers in the capacity ranges as shown below. Burner Sire 12 14 15 16 17 18 19 20 22 24 TECHNICAL DATA AND SPECIFICATIONS G. P. H. 8 15 22 30 45 70 .85 , 100 130 165 Boiler . Hone Power 24 45 66 90 135 210 255 - 300 . 400 : 500 So. Ft. Steam Radiation 3,300 6,000 8,800 12,000 18,000 28,000 34,000 40,000 52,000 64,000 Motor Size H. P. .| * f 1 -1 1.5 . . 2.0 3.0 5.0 5.0 . ACE AIR NOZZLE (Patent No. 2541347) The Ace variable-vaned air nozzle per mits accurate, efficient shaping of the flame to conform with the shape of the combustion chamber. The angle of the vanes can easily be changed in the field to any desired position to suit the boiler requirements and thus insure the maxi mum flame without oil impingement. SEND FOR ACE'MANUAL... PREPARED SPECIFICALLY FOR ARCHITECTS AND ENGINEERS. 1382 Heating Systems Burner*, on Automatic Burner Corp. 1823 W. Carroll Ave. Chicago 12, HI. "THE STANDARD OF THE INDUSTRY" MODEL 52A Domestic Conversion Oil Burner Famous for many years as the gun type oil burner that combines maximum effi ciency and economy with smoother, quieter, trouble-free operation. Fea tures exclusive ABC Choke, Spinner, Coupling and Oilairator mechanism for developing truly efficient combustion. Capacity 0.6 to 5.0 gph. MODEL 55 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 directly to the boiler by means of a flange. Among its many time-saving features are: 10 second nozzle removal, and a transformer which swings aside breaking electrical contact and permit ting easier drawer assembly removal. Capacity 0.6 to 3 gph. MODEL 54 For Commercial and Large Residential Use 'r 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 housing from both sides. With 2-stage pump. 4 to 10 gph. Industrial Oil Burner MODEL 53 Provides dependable, economical oil heat for small to medium sized factories, in stitutions, etc. Built-in safety 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 pump. Suit able for front or rear of furnace or boiler mounting. Capacity 9 to 16 gph. 1383 / N Heating Systems 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 B U R N E R SIZE O IL U.S. GALS. PER HOUR 1000 B T U GAS CU FT PER HOUR BO ILER HP STEAM EDR 240 B tu HOT WATER E D R 150 B tu . to a P5 O E-* O S AA-3 A-3 C-3 E-3 F-3 G-3 H-3 J-3 K-3 L-3 M-3 A H H H 1 l 2 3 3 5 4 7 15 20 28 35 50 70 100 135 200 *Non-Pump only 600 1,050 2,250 3,000 4,200 5,250 7,500 10,500 15,000 20,250 30,000 13 23 50 67 93 116 166 233 333 450 666 1800 3,200 6,950 9,310 12,930 16.125 23,075 32,390 46,290 62,550 92,575 2,880 5,120 11,120 14,900 20,700 25,800 36,900 51,800 74,000 100,000 148,100 All maximum capacities are necessarily approxi- mate. Burnere installed with adequate draft provi sions and correct furnace volume, properly designed, will develop capacities indicated, at sea level. V-BELT DRIVE All Enterprise-Burners are equipped with V-belt drive, allowing for the selection of a standard . motor to fit precisely.the voltage and torque require ments. Any replacement or repair service of standard motors is readily... avail able through nationwide service facil ities of motor manufacturers at stand ardized prices. Enterprise V-belt drive provides for various fan and atomizer speeds as necessary to insure efficient operation for both normal and unusual combustion requirements. OPERATION Selection of burner type depends on the articular requirements. Industrial type umers are designed for manual or various forms of semi-automatic con trol. Full automatic burners are gen erally specified for commercial heating lants, public buildings, apartment ouses, hospitals, and. general industrial service, to obtain efficient, economical burner operation without the need for a constant attendant. Manual, semi-automatic and full auto matic burners are furnished as standard equipment in pump type, and non-pump type "as shown in specifications chart. Non-pump type requires separate pump sets to furnish oil supply. Standard fuels are No. 5 oil, or No. 6 (Bunker "C") oil, preheated. OPTIONAL EQUIPMENT Gear Pump--for all sizes except L-3 and M-3 Metering Pump, dual type--for all sizes except L-3 and M-3 Fixed Fire Start--Sizes AA-3 through F-3 Low Fire Start--All sizes Modulating Control--All sizes Combination Oil and Gas--All sizes Electronic Controls--All sizes COMBINATION OIL--GAS BURNERS Enterprise Combination Burners are de-... signed to use whatever gas is readily ; available--natural, manufactured, or the .' by-product of a gas producing processe. They are adaptable as well to the use of a wide range of fuel oils. Automatic burners are supplied with standard gas-electric ignition with constant gas pilot for gas fuel, and intermittent gas pilot for oil fuel. METERING PUMP The Enterprise Metering Pump auto matically compensates for changes in viscosity, keeps the firing rate constant. It eliminates the need for compensat ing valves, metering valves, and m some cases relief valves. This is optional equipment, available for all sizes except L-3 and M-3. Engineers will be provided with com plete mounting dimensions, piping dia grams, wiring diagrams and combustion chamber designs for specific installation requirements. Consult with manufac turer before preparing specifications. Full information on request. Enterprise Burners have been tested, approved and listed as standard by Underwriters' Laboratories, Inc., and by other recognized boards and bureaus of safety measures and controls. 1384 Heating Systems Bnmn, on Trade Mark Burner Co. Head Office: San Rafael, Calif. Factory Representatives in 18 Principal Cities Automatic electric igni tion floor furnace. Dual register wall discharge models also. Domestic, Automatic, Natural Draft Electric Ignition Heating Equipment Complete line of domestic heating equipment, specifically de signed to burn low cost furnace oil. Burners and complete units listed by Underwriters' Laboratories. Conventional ther mostat control operates automatic electric metering valve and simultaneously turns on patented low voltage 3-volt ignition coil shown in burner. The floor furnaces, circulating heaters and wall furnaces shown offer high quality, low initial cost, automatic heat for small homes. The forced air furnaces offer basement type and first floor utility type automatic heating systems which are clean and quiet in operation. Special sus pended ceiling furnace for industrial use saves floor space and offers individual zone thermostat control with directed forced air circulation. HOURLY CAPACITIES AND RATINGS OF UNITS. Automatic electric ignition or manual control circulating heaters. Type of Unit Sizes Available Max. Thou. Thou. Blower Cap. Btu Btu Gal In Out lons put put VtoI * Automatic Burnera Dual or Floor Manual Heaters Wall Furnaces #00 0 9# 1 2 3 4 #70-47 Cl 70-47 Dual 100*47 Cl 100-47 Dual #59 71 108 #60 80 .25 .45 .62 .80 1.25 1.75 2.50 .48 .60 .70 .75 .45 .50 .75 .37 .60 35 60 87 114 175 245 350 65 70 95 no 62 71 108 53 84 26 45 65 85 130 183 260 50 55 75 80 43 53 77 42 65 Dimen. o. JS H.W.D. Usage .2 Inches u< 9 7 22 Convert8 9 8 23 ing Do- 9 9 25 mestic 9 10 28 Coal to 10 12 32 Oil Burn11 14 36 ing Fur12 16 38 naces 45 23 23 Homes 60 23 32 without 45 23 41 base* 60 23 44 ments 31 28 20 Heating 41 28 20 Small 43 36 21 Homes 51 29 20 No Base80 30 20 ment Automatic electric ignition conversion burner. . (Below) Automatic electric ignition tcaU furnacefor homes vritA concrete floors, dual heat discharge. A-AC-2 Basement B-AC D-MF #1 Air Fur* D-MF #2 naces A-UC DU-44 CIBL DU-46 CIBL Furnace CF-140 .75 1.12 1.60 2.45 .75 .80 1.15 1.35 105 155 230 340 105 112 160 190 84 9' 1000 i 45 20 54 Homes 125 10 1500 57 23TO with 178 14 2400 i 60 41 65 Base* 260 16 3600 \ 66 47 77 ments 84 9r 1000 i 71 21 37 Duct Distribo- 80 7 650 l 60 22 28 tion in Attic 120 10 1300 i 79 28 35 Garages, Stores A 145 10' 1000 i 49 62 39 Factories L. to r. Automatic electric ignition furnaces: basement, first floor utility room, suspended ceiling furnace for industrial um. 1385 Heating Systems Burners, on S. T. Johnson Co. Builders of Domestic and Commercial Oil Burners 940 Arlington Ave., Oakland 8, Calif. 401 No. Broad St., Philadelphia 8, Pa. , Self-storage water heaters, separate burner units, burner-boiler units, conditioned air units, range burners and various specialized items comprise the line-up of John son light-oil Burners. _ There is a wide range of sizes and capacities in each classification with which heat ing engineers and contractors can successfully meet every type of problem. Every Johnson Burner is backed by an unbroken record of fine engineering and excellent craftsmanship that dates back to 1903. Heating Systems Burners, on S. T. Johnson Co. Builders of Heavy-Duty Industrial Oil Burners 940 Arlington Ave., Oakland 8, Calif. 401 No. Broad St., Philadelphia 8, Pa. Johnson Industrial Burners are designed to operate on Heavy Oils which prodiicie extra heat at low cost. They increase the capacity of equipment formerly fired with coal and produce desired steam pressures more quickly. Automatic regulation per mits the boiler to operate with maximum efficiency at any specified steam pressure, without watching, care or attention, thus reducing labor costs. They have been installed with marked success in hotels, hospitals, factories, office buildings and other large structures all over America because they provide heating engineers with a wide range of capacities and with every desired feature of economy, performance and automatic control. In design and construction, Johnson Burners combine modern engineering techniques with the "know-how" and skill acquired in '49 years of practical experience in building fine oil burners. ,' BANKHEAT BURNERS Fully auto matic, pressure atomizing type. Sizes up,to 20 gph. HEATLUX HOUSE HEATERS (left) Fully automatic Bankheat Burners. Hot water heat. 2 sizes. AOULUX WATER HEATERS (right) Fully automatic, self-storage. Capacity: 100 to 540 gph. TYPE 30 AVH--Fully Automatic. Pre heater type. BurnsNo.60il. Sixsizes, 20 to 300 horse power output. ' AQULUX WATER HEATERS, Heavy- Duty Models Either self-storage or sepa rate storage. Fully automatic. Low fuel consumption and costs. Oil Burn ECONOLUX HEATERS Fully automatic Steam and Hot Water Units, 150 to 830 Mbh. ing models up to 540 gph. Combination Coal or Oil models up to 2000 gph. Combination Gas or Oil models in all sizes. 1386 TYPE 28 Manual and semi-automatic. With or without built-in pumps. Burns No. 5 and No. 6 Oils. Seven sizes, 2 to 135 gph. Illustration shows burner swung away from fire-hole-plate for easy inspection. 1387 Heating Systems Burners, ou Petroleum Heat & Power Company . . Stamford, Conn. DOMESTIC OIL HEATING EQUIPMENT PRESSURE ATOMIZING DOMESTIC BURNERS--Applicable to steam, hot water, or warm air systems, for use with No. 2 or lighter fuel oils. Listed by Underwriters' Laboratories. Models CA-1, CA-2. New type air dis tributor head for maximum combustion efficiency. Intermittent ignition with electronic or standard controls. Models P-9-70A, P-9-70. Standard, reli able "gun" type burner with constant electric ignition. Choice of. three pack age controls. Models P-12-3, P-13-A3, P-13-3. For larger residences, stores, garages and commercial buildings. No. 2 or lighter oil. Burner Model Number CA-1 CA-2 P-9-70-A P-9-70 P-21 P-22 P-12-3 P-13-A3 P-13-3 Nozzle Size gal per hr Total Capacity Steam sq ft Hot Water sq ft .75 to 2.00 300- 800 2.00 to 4.00 800-1600 1.00 to 1.50 400- 600 1.65 to 2.50 660-1000 2.00 to 4.50 800-1800 3.00 to 6.00 1200-2400 6.00 to 10.00 2400-4000 9.00 to 12.00 3600-4800 12.00 to 18.00 4800-7200 480- 1280 1280- 2560 640- 960 1050- 1600 1280- 2880 1920- 3840 3840- 6400 5760- 7680 7680-11520 Front view 0/ Petro Petro Strict "A" Standard Automatic Winter Air Boiler for Steam Conditioner Petro Storage Type Hot Water Heater PETRO MODEL HT OIL HEATING UNITS--The Petro Model HT Boiler normally delivers steam in as little as 43 seconds. With or without 3 gpm domestic hot water coil. Model HT-S3 rated 375 sq ft, and HT-S4, 450 sq ft, steam. Model HT-W3, 600 sq ft, and HT-W4, 720 sq ft, water. The Petro Model HT-A3 Warm Air Con ditioner is a compact electronically con trolled unit. With or without 3 gpm domestic hot water coil. Rated 110,000 Btu at bonnet, 90,000 Btu at register. Capacity 1250 cfm. OTHER PETRO HEATING UNITS Standard Model Petro Automatic Boil ers, in two sizes, for steam and water, are Bteel boilers designed for small home field. Series "A" Winter Air Condi tioner in three sizes from 75,000 to 115,000 Btu at register. Storage Type Water Heaters operate on No. 2 oil and heat 120 gph 100 F temperature rise. Send for Petro Domestic Catalog. Heating Systems Burners, on Petroleum Heat & Power Company Main Office and Factory: Stamford, Conn. "Since 1903" ... Good Oil Burning Equipment... Fuel Oils INDUSTRIAL AND COMMERCIAL OIL BURNING SYSTEMS Model WD-AH DirectDriven Rotary-Cup Type Burner. On w-6 and larger sizes, Modutrol Firing is standard. On smaller sizes, it is supplied as an extra. PETRO MODEL W BURNER is avail able in two types: (1) Direct-Driven, which includes electric motor, fan, pump, rotary cup atomizer in one self-contained assembly, together with air and oil con trols. (2) Belt-Driven, containing the same assembly as above except that the integral motor is replaced by motor mounted outside burner housing and arranged for belt drive. Removable ro tary cup and nozzle permit changing shape of flame to suit any boiler furnace reauirements. Interlocking air and oil control mecha nism permits any minimum or maximum operation required within the burner's range of operation. Counter-flow Angu- lar Air Vanes at nozzle increase air and oil turbulence and aid efficient combus tion of heavy fuel oils. Special oil adjustment valve meters oil to rotary cup, yet permits manual opera tion without disturbing permanent burner adjustment. Model WO-A Belt Driven, Rotary Cup Type Oxl Burner. FOR UNHEATED COMMERCIAL OILS: Model W-A--Automatic ignition and operation with synchronized control of oil and air. ' Model W-SA--Semi-automatic, i.e.: automatic variation of firing rate with manual ignition; also available for man-, ual variation and manual ignition. FOR PREHEATED OILS: HEAVY NO. 5, Models W-A-E and W-SA-E; No. .6 (BUNKER "C"), Models W-AH, W-SAH. Models W-A-E; W-AH--Automatic igni tion and operation with synchronized control of oil and air, and automatic control of oil heaters. Models W-SA-E; W-SAH--Semi-auto matic with oil heaters, i.e.: automatic variation of firing rate with manual igni tion ; also available for manual variation and manual ignition. CAPACITIES at 70% Boiler Efficiency Model W-2K W-3 W-4 W-5 W-6 W-7 W-8 W-8M W-9 Motor H.P. H a M 1 2 2 3 3 3 Mat. Gals, per Hour Rated Cap. B.H.P. 11 34.4 15 47.0 25 78.5 35 110.0 50 157.0 70 220.0 too 313.6 120 376.0 145 454.7 Sq. Ft. E.D R. Steam Rad. 4,810 6,560 10,940 15,300 21,880 30,600 43,750 52,500 63,250 These burners are available for all types of electrical current supply. PETRO MODEL GW COMBINATION GAS AND OIL BURNER, direct or belt driven. Independent combustion of each fuel--60 seconds to change from one to the other. Maximum combustion effi ciency from either fuel. PETRO'S THERMAL VISCOSITY CONTROL A dependable and accurate control of viscosity--and hence delivered combus tion efficiency--is through the heat ap plied to the oil. Petro's Thermal Vis cosity System controls this heat-applica tion at its source. CAPACITIES. Model BTU GW-4 GW-5 GW-6 GW-7 GW-8 . 3,750,000 5,200,000 7,500,000 10,500,000 15,000,000 OU* GPM 25 35 50 70 100 Gas* Cu. Ft/Hr 3,750 5,200 7,500 10,500 15,000 * Based on oil of 150,000 Btu/gal and gas of 1,000 Btu cu ft. Send for catalog of Petro Commercial and Industrial Oil Burners 1389 Oil Burners 9Heating System wt Heaters * -Air Conditioning Unit Ray Oil Burner Co. Since 1872 1301 San Jose Avenue San Francisco 12,;Cal. Distributors in All Principal Cities of the World Atlantic Seaboard Division 629 Grove Street 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; Oil Burning Water Heat ers ; Winter Air Conditioning Units, Commercial Ranges. . Oil Burners Heating Systems water Heater* Air Conditioning Unit Ray Oil Burner Co. Since 1872 1301 San Jose Avenue San Francisco 12, Cal. Atlantic Seaboard Division 629 Grove Street Jersey City 2, N. J. There is a RAY Burner for every Heating Purpose. 1 to 1000 Boiler ftp Type AG. Manual, Semi-Au tomatic. RCR for Ht oU, manual operation. -. Steam Turbine Drive, Type TG, all grades oil. Tested and approved for U. S. Navy Service. Four, 8 oven, fully auto matic oU Ranges. . . 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 drivesythe latter being recommended for use where other than 50 or 60 Cycles AC, or only DC is available. Types for straight elec Type ARJP, Fully Au . trie or straight gas ignition; pump or gravity feeds. Direct tomatic for heavy oil drive types include a steam turbine driven model. where gas for ignition not ' All fully automatic types for heavy oil incorporate the Ray available. Dual Pump and Reservoir, with the Ray VISCOSITY Valve, a patented, exclusive feature which automatically meters the correct amount of fuel at all times, regardless of changes in viscosity of the oil due to temperature variations. All larger 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. Type. AR144 Size 10 for No. 6. oil. Available tn 10 sizes from t to 810 gph. RAY PRESSURE ATOMIZING OIL BURNERS . Fully automatic, for No. 2 oil or lighter. AC or DC; capaci ties to 18 gal/hr. RAY WINTER AIR CONDITIONING UNITS Built in four sizes, with input capacities of 105,000, 140,000, 230,000, 350,000, 450,000 Btu. .. RAY OIL WATER HEATERS Four sizes. Capacities: 35, 45, 60 and 75 gal. Maximum recover rates: 100 to 240 gph. RAY OIL FIRED RANGES . Seven sizes for manual or fully automatic operation. Type BR-141, Belt Drive Automatic. tYi to 100 gph. Ray OU Furnace, Winter Air Conditioning Unit. Small capacity to ty$ gph) rotary burner, 1390 Fully Automatic, Type JP, ft or lighter oU ARC-MODEL 50. This burner 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 concentric with the nozzle. Change from one fuel to the other requires less than one minute. Avail able in ten sizes; in 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 eleven sizes; in capacities to 43,000,000 Btu/hr. TYPE XPJC. Combination gas-oil burner of the pressure atomizing type. Available in three sizes; in capacities from 560,000 to 2,500,000 Btu/hr. HOURLY CAPACITY RATINGS of RAY OIL BURNERS Burner Size JP XPJ XPJ-1 XP-2 0000 000 00 0 1 % 8 66 1 li 72 83 9 KlO 12 8 7 I 1 Motor H . P. Oil Capacity U. S. Gallons Min. 1 1 3 8 Max. 3 4 8 18 Equivalent Boiler HP Min. 3 3 9 25 Max. 9 12 25 56 0.5 2.5 2 8 0.5 2.5 2 8 1 2.5 3 8 25 7 16 4 11 5 15 8 22 13 35 17 50 27 72 10 33 12 50 15 67 25 100 35 110 40 165 50 225 85 335 35 150 120 500 50 210 ' 165- 700 75 320 . 250 1000 Equivalent Lbs. Steam Generated Min. Max. 110 325 110 430 325 865 865 1950 60 290 60 290 no 290 230 580 460 1250 580 1720 930 2500 1150 1400 1720 2900 3800 5800 7750 11500 4000 . 5800 8700 17400 24400 37000 iT* Heat Capacity Input Thou. Btu Oil or' 3000 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 75 375 234 1170 75 375 234 1170 150 375 469 1170 300 750 938 2350 600 1650 1870 5170 750 2250 2350 7030 1200 3300 3750 10,300 1500 1800 2250 3750 5250 7500 11250 4950 7500 10000 15000 22500 31500 48000 4690 5620 7030 11700 __ -- -- 15500 23400 31400 46900 __ -- ~ NOTE: These ratings ax* predicated upon specific conditions o! draft and furnace voiume. 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 baaed upon 150,000 Btu per gal of oil for rotary burners and 140,000 Btu per gal of ou for pressure atomizing burner* and upon an overall boiler efficiency of 75 per cent. 1391 Heating Systems oomers' RflyriELD C. L. Company AUTOMATIC 2010-18 S. Halstead Street, Chicago 8, Illinois DOMESTIC, COMMERCIAL AND INDUSTRIAL OIL BURNERS FOR ALL GRADES OF FUEL OILS, FOR SMALLEST TO LARGEST BUILDINGS For No. t or No. S Oils For No. 4 or No. 5 Heavy Oils For No. 5 or No. 6 Heaviest Oils 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 COj 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 models are all-electric operating, self-lubricat ing and have self-cleaning nozzles for long, 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 of 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. 1392 r . I j Heating Systems Burners, ou Williams Oil-O-Matic Division EUREKA 'WILLIAMS CORPORATION, BLOOMINGTON, ILLINOIS Manufacturers of Automatic Fuel OU Burners and Complete Heating Units for Steam, Hot Water and Warm Air. OIL BURNERS Model Fifty-Ten METERED LOW PRESSURE--Easily installed in any type heating plant. Uses any domestic fuel oil including the new catalytic oils. Model Fifty-Ten, Oil-Air Nozzle is guar anteed for life. Model Fifty-Ten K-4.5 K-7 Oil Capacity Gals, per Hr Min. Max. .6 2.50 4.00 3.0 4.5 7.00 Motor Atomizing HP RPM Pressure It 3450 1 to 3 lbs. 1725 2H lbs. H 1725 3 lbs. WUliams HI-PRESSURE Oil Burners . . . precision built for those who want high quality at low first cost. Readily installed in any type heating plant. Model AX HP-7 Oil Capacity Gala, per Hr Min. Max. 1.00 3.50 3.00 7.00 Motor Atomizing HP RPM Pressure * 1725 100 lbs. H 1725 100 lbs. BOILER-BURNER UNITS UTILITY MODEL 1--For upright instal lation in utility room, closet, or as space heater! 70,000 Btu--for small, insulated basementless home. 22 x 25 in.; 65 in. high. UTILITY MODEL 1-S--For space-saving horizontal installation in attics, base ments, utility rooms, service stations, stores, garages, or as floor furnace.70,000 Btu. 22 in. x 25 in.; 65 in. long. MODEL 70A--For small homes with basements. 70,000 Btu. Completely wired and assembled at factory. Stand ard or Deluxe models. All steel casing. Superlative styling. MODEL 10A--For 6 to 10 room home featuring famous Oil-O-Matic vertical counterflow principle. 100,000 Btu. Fuel-saving performance. Standard or Deluxe Models. B-SERIES--Steel Boiler-Burner Units, 4 sizes for steam (320-700 sq ft) ; 4 sizes for hot water (510-1120 sq ft). Built-in water heater optional. Welded all-steel con struction. Compact, rugged, efficient! C-SERIES--Cast-iron Boiler-Burner Units, 4 sizes for steam (300-750 sq ft); 4 sizes for hot water (555-1340 sq ft) for homes of 4 to 14 rooms. Built-in water heater optional. Standard or Deluxe models. MODEL 15A--For large 10 to 15 room home, small commercial establishments; featuring vertical counterflow. 150,000 Btu. Plentiful volume at low cost 1 Stan dard or Deluxe models. All Winter Air Conditioners and BoilerBurner Units feature the Model FiftyTen Low Pressure Burner for Maximum Efficiency and Economy. Factory engi neered and tested as integrated units. 1393 Heating Systems Burners, on York-Shipley, Inc. Main Office and Plants--York 16, Pennsylvania OIL-FIRED EQUIPMENT FOR INDUSTRY . HORIZONTAL ROTARY BURNERS STEAM-PAK GENERATORS Model AHPM direct-drive fully automatic pump-type burner with full modulating sys tem, for heating or process work. Uses No. 6 oil. York-Shipley Horizontal Rotary Burn ers cover the range from 45 to 400 boiler hp, and are built in direct-drive and beltdrive types. Models are offered for use of fuel ons No. 1 through No. 6 (light dis tillate to most viscous bunker oils), for manual, semi-automatic, or full modulat ing control, with or without pumps. The extremely wide range of models and sizes, high efficiency, and adaptabil ity of this line assures easy selection of the right unit to fit any type or shape or make of boiler, with long life ana low operating cost. Three significant engineering develop ments provide -precision combustion. The Iris Shutter, which gives absolute con trol of burner air, causing metered vol ume of burner air to remain constant; The Flame-Former, which shapes the flame to fit combustion chambers of any type; and The Automatic Torch Lighter, a pressure-type igniter for smooth and positive automatic starting. All York-Shipley Industrial products are sold, engineered and installed by local distributors who have been selected because of their knowledge of engineering and of equipment using heavy oils. .Model SPLSO-5 low-pressure boiler for heat ing applications. A three-pass, down-draft, horizontal fire tube design. Uses No. 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 commerical 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. 1394 INTERNATIONAL HEATING & VENTILATING EXPOSITION THE AIR CONDITIONING EXPOSITION Permanent Address--Grand Central Palace, New York 17, N. Y. EXPOSITIONS HELD Philadelphia, 1951; Chicago, 1949; New York, 1948; Cleveland, 1947-1940; New York, 1938; Chicago, 1936; New York, 1934; Cleveland, 1932; Philadelphia, 1930. FUTURE SCHEDULE The 1953 Exposition will be held at International Amphitheatre, Chicago, 111., January 26 to 30, 1953. 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 Grand Central Palace, New York 17, N. Y. EXHIBITORS Comprise leading firms in each phase of the industry; number has varied from 150 to 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. 2. The Oil Burner Group: 3. The Hydraulic Group: Water feeders, water heaters, pumps, . traps, valves, piping, fittings, expansion joints, pipe hangers, etc. 4. The Steam Heating Group: Vapor heating, steam specialties. 5. The Hot Water Heating Group: 6. The Air Group: . Warm Air furnaces and stoves, registers and grilles, cooling towers, air filters, motors, fans, blowers, 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, and does all these in proper season for com plete, all year-round air conditioning. 8. The Control Group: Instruments of precision for indicating, controlling or recording temperature, pressure, volume, time, flow, draft or any other function to be measured. 9. The Refrigerating Group: Compressors, condensers, cooling 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 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 organizations, public utilities, real estate management concerns, etc. A detailed analysis of registered attendance is available on request. Industrial Expositions in America lead the expositions of the world in style, business effectiveness, industrial influence and educational value. This Exposition.stands among the leaders in Industrial Expositions in America.. It is an educational institution which brings together the research develop ments and improvements in equipment and materials for use in heating, venti lating and air conditioning all types of buildings. - I ^ Heating Systems Hot w.ter 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 & G Hydro-Flo Forced Hot Water Heating System. It is built as a horizon tally driven unit for sound engineering reasons which have demonstrated their practical value in thousands of installa tions. This construction makes possible many desirable, exclusive features. 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 every revolu tion count by holding water slippage to a minimum. OH 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 castiron and copper. B & G Motorized Valves Thermostatically operated valves used to cdhtrol boiler water flow through in dividual circuits of zoned heating sys tems. B & G Boosters have a genuine oilcirculating lubrication system--one of the greatest reasons for quiet, depend able, economical operation. Oil is drawn up f rom the oil well by wool fibre wicking and dropped on the horizontal bearing 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 B & G Universal Pumps Designed for forced hot water heating systems in apartment and office build ings, factories, schools, etc. The in stallation can be operated as a large single zone or divided into several zones with circulation of pumped water in each circuit controlled by a B & G Motorized Valve, operated by a zone thermostat. 1396 Bell and Gossett Company Healing Systems Hot Water Heating Heat Transfer HOT WATER SYSTEMS AND SPECIALTIES B & G Relief Valves Designed and built to ASME require ments. Tested by National Board--la belled with ASME symbol. For relieving excess boiler pressures in hot water heating systems, and in the lines of service water systems. B & G Relief Valves have the design features which assure dependable service. B & G Reducing Valves Fast operating valves for keeping hot water heating systems properly filled. Easily adjusted to meet varying building heights. Also high pressure reducing valves for protection of plumbing fix tures. B & G Type "CWU" Radiation Heater 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. Pumping the water through both heater and heating system affords ex cellent temperature control, and per mits use of much smaller pipe and fittings. B & G Type "SU" 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 m these units heats water instantly as needed. Available in a wide range of capacities. Outdoor type, wind-compensaling tem perature control. The Regulator pro jects through the building wall, with the indoor end warmed by water in the radiation circuit. A small amount of this heat is conducted to the outside end, where it is 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. 1397 ___________________ Heating Systems Hot Water H. A. Thrush & Company Peru, Indiana Represertatfres in Principal Cities ___ . FORCED CIRCULATING THRUSH FLOW CONTROL SYSTEM OF HOT WATER HEATING AND HEATING SPECIALTIES Horizontal Water Circulator Patent Noel 3,0SifiO9, 1,137,791, i,tm,l!3, tjxnjeos, tjts7,867, tjsejst, tjss.oio, sjufii , 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 effi cient, long lived and vibration-free. Sealed-in lubrication. Made in 6 sizes, 1 in., 1J in., 1 im, 2 in., 2 in., and 3 in. Hi-Head Horizontal Thrush Water Cir culators, designed for use with radiant baseboards, convectors, radiant panels, etc., which require higher heads, are also available in 1 in., 1} in., and 1J in. sizes. 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 tank, greatly improving heating efficiency by eliminating air from the system. 1 in. through 14 in. valves also available with solder type outlet unions. Made in six sizes, 1 in., 11 in., 1J in., 2 in., 2} in. and 3 in. THRUSH AUTOMATIC FILLING VALVES Whenever system pressure drops below 12 lbs, city water pressure will auto matically open the valve and admit water until the system is filled. THRUSH LOW PRESSURE RELIEF VALVES, PRESSURE TANKS Relief Valves protect heating boilers from excess pressures. Large metal diaphragm assures positive closing and opening. Thrush Air Tight Pressure Tank conserves water and fuel. Heated water expands into tank. 1398 H. A. Thrush & Company Heating Systems Hot water Patent reissue No. 19300 No. 201 THRUSH RADIANT HEAT CONTROL Automatically maintains room tempera ture within a fraction of a degree. Con trols both room and water temperature in the heating system, compensating to prevent variation in room temperature or a lack of radiant heat. No. 200 Thrush Relay Transformer supplies low voltage. THRUSH DUAL CONTROL UNITS Provide automatic pressure relief, auto matically fill and maintain water supply in hot water heating system. Built-in strainer. Made in four types, brass or cast iron, f in. or f in. Patent No. 3,180,930 THRUSH WATER HEATERS 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 lb maximum. 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. 76 HIGH PRESSURE AND TEM PERATURE RELIEF VALVES The relief valve illustrated at the right has an added safety feature. In addition to the relief of excessive pressure there is also provision for relief if excessive tem peratures develop. It has a fusible plug in an opening in the casting. An other type with a fusible insert in the stem which projects into the hot water line, is also available. The fusible plug or insert melts at 210 F. Both types are designed for use in the hot water outlet line. Bronze or Iron NON-ADJUSTABLE THRUSH SUPPLY TEES FOR ONE PIPE HOT WATER SYSTEMS Assure positive diversion to radiator. Available in threaded cast iron or in bronze with solder connections for cop per piping. Complete range of sizes. 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, not retarded. Available in bronze with solder connections for use with copper C. 1. Patent No. 3,101,99-- pipe and in threaded cast iron for steel Bronze Patent Applied for pipe. WRITE FOR NEW CONDENSED CATALOG 1399 Heating Systems Hot 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 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 New Horizontal Circulators There is a storage or tankless type Taco high duty, are quiet, rugged and power- heat.exchanger for every job--residential, ful. Packed in specially designed car- apartment, commercial or industrial. tons for quickly changing flange sizes. 1400 Heating Systems Pumps ^UEQlk Aurora Pump Company AllROtov GJjuXLjjA, XUMP 40 Loucks Street, Aurora (Chicago Suburb) Illinois w- Manufacturers of Turbine-Type, Vertical and Horizontal Centrifugal and Special Design Pumps Distributors in Principal Cities Barring Unusual Conditions We MAINTAIN A COMPLETE STOCK Apco Single Stage Turbine-Type Pumps. Also available tn Two Stage. FOR IMMEDIATE SHIPMENT Packaged Duplex Condeneation Re turn Unit with No. 4 Series Apco Pumps; designed for smaller jobs. LARGER UNITS up to 160 gpm capacity, horizontal and vertical also available. APCO PUMPS are IDEALLY SUITED to MANY HEATING and AIR CONDI TIONING DUTIES--CAPACITIES UP TO ISO 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 45 Ft. Sizes Available Va", l\in, f" MEDIUM HEAD TYPE--JHC--Close Cou pled Caps, 6 to 160 gpm. Heads to 100 Ft. Sizes Available 1", ljim, 1)6*. 9m APPLICATIONS Well suited as integral part of manufac turer's product such as air conditioning units, cooliDg towers, evaporator coolers, hot water circulators etc., also for gen 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 oh all sizes and is located in packing cover-- easily replaceable. IMPELLER is balanced, enclosed type of nigh grade bronze material. SHAFTS--Stainless steel on Types JMC, SAC and JA. Can be furnished on Type SA at additional cost. MOTOR Built to NEMA specifications and equipped with STAINLESS STEEL 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. Write for CONDENSED CATALOG "V" 1401 Heating Systems Pumjs 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: ENGINEERING REPRESENTATIVES ALBANY 7. N. Y., Mr. R. B. Taylor, 966 Broadway: ATLANTA. GA , Mr. J. J. O'Shea. 305 Techwood Dr, N. W.; BALTIMORE I, MD., Mr. C. A. Conklin III, 1014 Cathedral St.; BOSTON 79, MASS,, Mr. E. D. Johnson, 507 Main St., Melrose Station; CANADA BUMPS, Mr. A. S. Capwell, Kitchener, Ont., Canada; CHICAGO 9, ILL., Emmert & Tmmbo, 20 N. Wacker Drive; CINCINNATI 99, OHIO, Mr. S. O. Johnson, 2044 Colerain Ave.; CLEVELAND IS, OHIO, Weager & Sherman, 570 Hanna Bldg., Euclid at 14th St.; CORPUS CHBISTI, TEXAS, Langhammer-Rummel Co., 101 N. Alameda St; DALLAS l, TEXAS, Mr. T. H. Anspacher, 615 Tower Petroleum Bldg.; DEN VER COLORADO, Stearns-Roger Mfg. Co., 1720 Cal ifornia St.; DETROIT 16, MICHIGAN, Cwm-DeVisser Co., 2051 W. Lafayette Blvd.; GREENVILLE, S. CAROLINA, Mr. Roy A. Stipp, P. O. Bor 1796, 104 E. Stone Ave.; HOUSTON S, TEXAS, Mr. D. M. Robinson, 2609 Sunset Boulevard; 'INDIANAPOLIS 4, INDIANA, S. E. Fenstermaker & Co., 937 Ar chitects & Builders Bldg.; DAVENPORT, IOWA, D. C. Murphy Co., 305 Security Bldg.; DES MOINES 11, IOWA, D. C. Murphy Co., 840-5th Avenue; KANSAS CITY, KANSAS, Mr. W. K. Dyer, Box 966, Post Office Building, Mission, Kansas; LITTLE ROCK, ARKANSAS, Mr. J. L. Brown, Terminal Ware house Bldg.; LOS ANGELES IS, CAL., Halladay A Knauff, 804 Pershing Sq. Bldg.; LOUISVILLE 2, KENTUCKY, Mr.H. M. Lutes. 633 South Fifth St.; MEMPHIS, TENNESSEE, Humphrey-Wynne Co., 620. Sterick Bldg.; MIAMI, FLORIDA. Mr. H. L. McMurry & Co., 46 N. E. 6th St.: JACKSONVILLE, FLORIDA, K. L. McMurry A Co., 25 Riverside Viaduct; TAMPA, FLORIDA, H. L. McMurry A Co., % Peninsular Warehouse A Ter. Co., 411 Hampton St.; MINNEAPOLIS 2. MINNESOTA, E. Floyd Bell, 2102 Foshav Tower; NEW ORLEANS IS, LA., Devlin Bros., 1003 Maritime Bldg.; NEW YORK 7,N. Y., Johnson A Norman, 39 Cortlandt St.; NEWARK 9, N. J., Johnson A Norman. Room 205,27 Washington St;; OMAHA 9, NEBRASKA, Wain Engineering Co.. 2311 Douglas St.; PHILADELPHIA 9, PA., Davidson A Hunger, 1200 Cunard Bldg.; PITTSB URGE 99, PA., Mr. H. Lee Moore, 345 Fourth Avenuo\ROCHESTER 1, N. Y., R. D. Moyer, 846 Sibley Tower Bldg.; ST. LO UIS 3, MO., Mr. J. W. Cooper. 2118 Pine St.; SALT LAKE CITY 1, UTAH, Stearns-Roger Mfg. Co., 405 Kearns Avenue; SAN FRANCISCO 3, CAL., Mr. Chas. W. Lockhart, 1214 Central Tower Bldg.; .S'A.V ANTONIO, TEXAS, Langhammer Rummel Co., 300 Blum St.; TOLEDO 3, OHIO, Mr. Carl Eyster, 1118 Madison Avenue; WASHINGTON 5, D. C., Mr. G. S. Fr&okel, Mgr., 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 hydraulically bal anced (water enters each side of impeller with equal pressure and volume), which contributes to the smooth operation and efficiency, as do simply formed water passages in the casing. BULLE TIN 955-N. 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. BULLETIN 963-F. CLOSE-COUPLED SINGLE SUCTION PUMPS. Extremely compact design permits installation vertically or horizontally. Available with either threaded or flanged connections. Suited to hand ling hot water with low submergence. Impeller overhung on motor shaft assures permanent align ment. BULLETIN 975-C. SELF-PRIMING SINGLE AND DOUBLE SUC TION PUMPS. Positive prime is obtained al most instantly when pump is started, without use of foot-valve. All parts are accessible, and above liquid to be pumped. Can be automatically op erated in remote locations. BULLETIN 970-A. 1402 Heating Systems Chicago Pump Company 2330 Wolfram Street BRunswick 8-4110 Chicago 18 PRODUCTS--Return Line Vacuum Heating and Boiler Feed Pumps, Condensation, ' House, Booster, Fire Pumps, Circulating, Brine, Sewage, Bilge, Sludge, Pneu- matlc and Tankless Water Supply Systems and Automatic Alternator for Duplex , Sets of Pumps. Fig. D-D900--Duplex "Condo-Voce" with Duplex Double Automatic Control CLOSE-COUPLED PUMPS Boiler Feed, Circulating, Tank Filling, Water Supply Capacities range from 3 to 600 Gpm against heads up to 189 ft. Motors from 1 to 20 hp. Discharge 1 to 3 in. Closed and open type impellers. Bulletin 108. "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. Fig. D-9S00 Fig. N-8905--Close-Coupled, aide auction pump "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 250. . VERTICAL CONDENSATION PUMPS for Low and Medium Pressure for Sys tems from-500 to 100,000 Sq Ft Radiation HThe vertical condensation pump is designed to receive re turns from lowest radiation. The receiver is placed underground--an ordinary hole sufficing if necessary--and requires y.os'oo very little floor space. Unit is shipped complete, easy to Vertical install, assembled so as to prevent steam leaks. Special bear- Condenings 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 245,253 and 255. - 1403 Heating Systems Pumps ATLANTA BIRMINGHAM BOSTON BUFFALO BDTTK CHICAGO CINCINNATI CLEVELAND DALLAS Ingeusoll-Rand TM II BROADWAY. NEW YORK 4. N. Y. DENVER DETROIT DULUTH BL FASO HOUBTON KANSAS CITT KNOXVILLE LOS ANGELES MINNEAPOLIS NEWARK NEW ORLEANS NEW TORE PHILADELPHIA PICHEB PITTSBURGH Offices and agents throughout the world POTTSVHjLB SALT htm dXT BAN FRANCISCO SCRANTON SEATTLE err. louxs TUMA WASHINGTON WILMINGTON CENTRIFUGAL PUMPS The is 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 is 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 encountered 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. LIGHT-WEIGHT JACKHAMER The J-10 Jackhamer 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. - 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 range of steam pressures down to 1 lb per sq m. I-R COMPRESSORS OF ALL TYPES AND SIZES I-R Compressors are offered in all sizes and types from V* to 3000 hp, in pressures from a few ounces to 15000 psi, and in stationary or portable models. Air-cooled units range from V* to 100 hp. I-R Water systems are available for industrial and domestic uses. 1404 Heating Systems Pumps Peerless Pump Division Food Machinery and Chemical Corporation PLANTS: Los Angeles 31, Calif., Indianapolis 8, Ind. Offices: New York; Atlanta; Indianapolis; Chicago; St Louis; Tulsa; Dallas, Plainview, Lubbock, Texas; Albuquerque, New Mexico; Phoe nix, Arizona; Fresno, Los Angeles, Calif. PRODUCTS: ' "~ Vertical Pumps: Deep and shallow well pumps; water supply, boosting, circulating and waste disposal pumps; condensate pumps; sump pumps. All types of drive. Horizontal Pumps: General purpose horizontal split case and end-suction pumps; turbine vane type pumps; boiler feed pumps; condensate pumps; circulating pumps; process pumps. All types of drive. Seals: Mechanical shaft seals for rotative shaft equipment and pumps. From 1 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: 1-150 hp. Heads: up to 260 feet. Single stage design. Compact, versatile, dependable and efficient. Good hydraulic character istics. Completely described in Bul letin B-2300. 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: 1 in. x 8]^ in. through 4 in. x 13 in. Capacities: up to 750 gpm. Heads: to 230 feet; tempera tures to 200 F. A11 types of drive. Completely described in Bulletin B-1350. Also larger size, designated as type "A," to 48 in. discharge for higher heads and capacities. Completely described in Bulletin B-1300. 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 Hydro-Line compact, close-coupled vertical centrif ugal pump for limited NPSH applications (at right). Ideally applied to condensate service. Provides capacities up to 5000 gpm. Pressures: up to 1500 feet. Temperatures: up to 250 F. Pump is enclosed in steel barrel. Easily installed as a complete unit. Ruggedly constructed for heavy-duty service. Designed for minimum required NPSH. Completely described in Bulletin B-592. OTHER PEERLESS BULLETINS are available, completely describing each type of pump in the Peerless line. Request copies describing the type pump in which you are interested. 1405 Heating Systems Pomps 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 Standard with the heating industry for over eighteen years. Removes air and condensation from return lines of vac uum steam heating systems, discharging air to atmosphere and returning water to the boiler. _ Two independent units are combined in a single casing--an air unit and a water unit. Impellers of both are mounted on the same shaft. Pump is bronze fitted throughout. Supplied direct connected to standard electric motors, for belt drive, or for steam turbine drive. For continuous or automatic operation. Standard in capa cities up to 300,000 sq ft E.D.R. Larger units special. Bulletins Nos. 307, 308, 309, and 310 on request. Vapor Turbine Vacuum Heating Pump Jennings Vapor Turbine Heating" Pumps combine all advantages of the standard return line heating pump with a new type of drive, a specially designed low pressure turbine which operates di rectly on steam from the heating mains on any system, requiring a differential of only 5 in. of mercury, and returns that steam to the heating system with prac tically no heat loss. This pump affords the safety and econ omy which goes with continuous con densation return and steady vacuum, and at no cost for electric current. Fur nished standard in capacities up to 65,000 sq ft E.D.R. Larger units special. Bulletin No. 290 on request. Condensation Pump and Receiver Removes the condensation from radi ators in return line steam heating sys tems, particularly radiators set below the boiler water line level, and pumps the condensation back to the boiler. Pump is bronze fitted with enclosed centrifugal impeller of improved design. By making the pump casing a part of the return tank, ana bolting the motor base to the tank, floor space is conserved. The rec tangular construction permits installa tion in a corner against the wall. These pumps are furnished in standard sizes with capacities ranging from 1J to 225 gpm of water. For serving up to 150,OCX) sq ft of equivalent direct radia tion. Bulletin No. 319 on request. 1406 Heating Systems Pumps The Nash Engineering Company 234 Wilson Road South Norwalk, Conn., U. S. A. Sales and Service Offices in all Principal Cities SEWAGE EJECTOR For pumping unscreened sewage or drainage from basements below the street sewer level, handling crude sewage from low level districts, pumping effluent, sludge and other heavy liquids. The Jennings Sewage Ejector is of the pneu matic type. Air, compressed only to the pressure at which it is used, by a Nash Hytor Air Compressor, is motive power to pump the accumulated sewage from a pot to the sewer. There are no air stor age tanks, reciprocating air compressors or screens, no air valves. Furnished in several standard sizes up to 1500 gpm against heads up to 100 ft. Bulletins on request. Suction Sump and Sewage Pumps Jennings Sump Pumps are self-priming centrifugals for handling seepage water and liquids reasonably free from solids. Sewage Pumps are equipped with non clog type impeller for liquids containing solids. Suction piping only is sub merged. Centrifugal impeller and vac uum priming rotor are mounted on same shaft that carries rotor of the driving motor, forming a single moving element, rotating without metallic contact. Will handle air or gas with liquid being pumped, and because of self-priming fea ture are installed entirely outside of pit, affording accessibility for inspection or cleaning. Capacities to meet all re quirements. Bulletins Nos. 159,161, and 338 on request. Air Compressor and Vacuum Pump Nash Air Compressors operate on a unique and different principle. The one moving part rotates in casing without metallic contact. There is nothing to wear, and no internal lubrication. Nash Compressors deliver absolutely clean air; ideal for agitation of liquids, pressure displacement, and handling gases. Vacuum pumps ideal for priming pumps, blood sucking pumps in hospi tals, and wherever non-pulsating vacuum is required. Pressure 75 lb or vacuum 27 in. of mercury. Furnished for any capacity; special for higher vacuums and pressures. Bulletins Nos. 282, 325, 331 and 337 on request. 1407 Heating Systems pi Skidmore Corporation St. Joseph, Michigan Quality Heating Pumps for over a quarter of a century Write for Bulletin No. J9-A on Type W Pump Bulletin No. SI on Type CV Pump SKIDMORE TYPE UV PUMP The Skidmore Type UV Condensation Pump, single or duplex unit, is designed for use where returns are too low to permit the operation of horizontal typo 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 Vertical Type CV Con densate Pump and receiver is designed for maximum efficiency in returning condensate to the boiler, or other points, from all types of low pressure steam heating systems and process equipment. Type CV Pump requires a minimum of space. The integral pump casing and motor is of cast iron construction, bolted to top of receiver. Pump is bronze fitted throughout, with enclosed centrif ugal 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. ll-A on Type HS Pump Bulletin No. 17 on Type TU Pump SKIDMORE TYPE HS PUMP SKIDMORE TYPE TM PUMP The model HS Condensation pump is economically designed to offer maximum efficiency with lower operating cost. The Type HS will operate at high temperature encountered in condensa tion pump service. The pump can be disassembled without disturbing piping connections. Furnished in either single or duplex type. Pump casing is.con structed of heavy close grain cast iron, vertically split, bronze fitted throughout. Capacities 1,000 to 65,000 sq ft EDR, pressures t1n0 tao. n7e5 l1b1_s_. The Type TM Condensate and make up water pump is of turbine type de signed for high pressures, for boilers up to 250 hp and pressures up to 150 lbs. Type TM pump consists of motor, steel receiver, automatic make-up valve mounted on receiver, water level gage glass mounted on receiver, self-cleaning strainer between pump and receiver, assembled and mounted on steel base. Cast iron base furnished if required. Electric boiler water level controller furnished for mounting on boiler. Write for Complete Engineering Data Bulletins on Skidmore Condensate or Vacuum Pumps will be sent on request 1408 Heating Systems steam fames cJones New York Office: 101 Park Avenue 128 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 Series K Valve 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 Valve The Series F Valve has no dial or pointer and is therefore fur nished 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, non-rising stems, renewable disc seats, .4of packless design. Made angle pattern in 1, and in. sizes; straightway (globe) pattern in % and 1 in. sizes. For use in vapor or vacuum systems. Size valve..................... x* X' l' DC Capacities--Sq Ft B. D. R. 2 ounces pres.............. 25 BO 90 160 8 ounces pres............... 45 90 160 280 Type H Valve 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 pres sure differentials of 1, 2, 3, 4 and 5 pounds, % in. valve up to 100 sq ft. 1 in. valve over 100 sq ft. Thermostatic Radiator Traps The B & J precision made thermostatic 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. Capacities-- Sq Ft. of E.D-R. Size No. Medium and high pressure traps suitable for pressures between IB lb and 100 lb can be furnished . X X 1 122 134 147 Pres. Diff.--Lb9. per Sq In. X X 1 2 5 15 70 92 168 228 320 610 120 152 320 450 710 1260 200 300 590 760 1200 2200 Capacities Lbs Water per Hour Float and Thermostatic Traps Made in five sizes for handling large and sudden loads of condensate that are greater and more variable than can be handled efficiently by thermostatic traps. Size No. Pres. Diff --Lbs. per Sq In. X X 2 5 15 X T41 70 100 200 210 230 1 T42 175 250 500 525 575 IX T43 425 600 1200 1260 1380 IH T44 850 1200 2400 2520 2760 2 T45 1775 2500 5000 5250 5750 Medium pressure F. & T. traps in H in. and 1 in. sizes can be furnished for pressures up to 65 lb. Suitable for pressures up to 15 lb. 1409 Heating Systems Specialties The V. D. Anderson Company Representatives In all I960 West 96th Street, Cleveland, Ohio principal - `dtles Manufacturers Of Steam Traps For Over 60 Years SUPER-SILVERTOP STEAM TRAPS Are inverted bucket steam traps of an improved, thoroughly tested design. These steam traps automatically remove both condensate and air from the steam system--no manual operations are nec essary. APPLICATIONS 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 then carried away in the discharging con densate. Super-Silvertops are used on any steam-using equipment where it is de sired to remove condensate and air auto matically in order to produce maximum heating efficiency. FEATURES No Restricting Passages--Even in the smallest sizes there are no narrow cored passages to become clogged with scale. Cannot Air-blnd--As the air is auto matically discharged ahead of the con densate in each cycle of operation. Simplified Piping--Connected either as an elbow or straight-in-line--only . one nipple needed since the U-tube is inside the' trap. Saves as much as three elbows, three' nipples and 60 minutes of time, compared to other inverted bucket steam traps. Precision Parts Alignment--The bucket does not swing free. It is con trolled in true engineering fashion, guided on a hexagonal tube. This makes a knife-edge contact, eliminating almost all friction. The unusual guide arrange ment keeps all parts in proper alignment Vacuum or Pressure--These traps do not leak steam. No danger of vacuum being destroyed--trap is recommended for vacuum operation. INSTANT HEAT Anderson Super-Silvertops can be equipped with Thermal Air Eliminators or Combination open float and thermo static steam traps can be used where instant heat is desired. Other Anderson products are: float-type steam traps, air release valves, and pipeline strainers, purifiers and separators. Note: Write for Free Copy of Book "S )LVING STEAM TRAP PROBLEMS." The V. D. Anderson Co. Heating Systems specialties Size No. Trap............ no Size Connections....... VS (See Note)............... only 2Shipping Wt., Lba__ H Diameter, Inches..... 4 Height, Inches........... 4*6 Max. Gs. Pressure.... 100 List Price.................... $10.00 SIZES. LIST PRICES. AND CAPACITIES 118 5 3X 4*6 150 $9.00 119 6 3H SH 200 $10.00 v12s0 or VS 7 3M 62 200 $12.00 21 :& 8 4* 651 200 $14.00 22 VS or 1' 14 5M 8*6 250 $23.00 v2s3 or 1' 16 5*6 10*6 '250 $32.00 24 or IVS 38 8% 13% 250 845.00 25 or 2r 75 9*4 1726 250 $60.00 WITH THERMAL AIR ELIMINATOR List Prioce.................... Differentia]l Pressure_______ 1 5 10 20 50 100 150 200 250 $11.60 1[ 8H10.60 | $>11.60 | $*1133.60 |I $<15.60 1I $Z268.20 tI $>35.20 I CAPACITY IN POUNDS OF WATER PER HOUR 137 161 225 390 775 1050 1500 305 360 510 970 1700 2300 3200 435 505 705 1190 2000 3200 4600 300 , 700 980 1650 2000 3500 6000 455 650 900 1400 1600 3100 4500 440 455 675 1200 1600 2450 4200 500 740 1310 1700 2900 3400 450 580 1000 1200 2000-- * 3700 655 1100 1300 2200 4150 1900 4500 $M49.8M0l I itfaifti 4an 2400 5274 7500 11100 7500 ' 10000 8000 8600 8900 9600 9200 21000 29650 40300 26000 25300 19100 20500 16800 13750 Size No. Trap................ ... Size Pipe Connections -. ... Shipping Wt., Lbs........ ... Diameter in Inches___ .. Height in Inches........... .. Max. Ga. Pressure*___ .. List Price........................ .. 119B % 7 3H 50 $14.00 COMBINATION TRAPS 120B VS 8 in 50 $16.00 21B H' 9 4% 8H 50 $18.00 22B \' ' 15 5*6 10*6 50 $27.00 Differential Pressure 1 5 10 15 20 30 50 CAPACITY IN POUNDS OP WATER PER HOUR 315 546 710 905 1032 1180 910 1100 480 820 1170 1390 1600 1850 / 1310 1600 865.'. 1504 1900 2200 1950 . . 2200 1500 1800 1140 1994 2500 3400 3500 3700 3700 3300 23B 1' 17 5*6 12*6 50 $36.00 1590 2654 3400 4800 5600 6200 4700 4700 24B i nr 39 8*6 15% 50 $49.00 2550 4275 11350 7800 Capacities based on continuous flow. When ordering be sure to specify maimnm steam premure. Note: Pipe sizes shown in heavy type are standard and traps will be shipped tapped standard unless other- w^espec^ed. Pipe sizes shown in light type furnished at no additional cost but only from Cleve- lana stock. * * Combination Trope ore available far preeettres op to 150 pei. Pricev. capacities and other information available upon application. - ANDERSON STRAINERS Anderson Self-Cleaning Strainers remove scale, grit, and sediment from the line. Stainless steel strainer screens- (brass on in. and 3 in.) are standard equipment and have an extremely large free area. Standard screen for steam and other gases has \4t in. openings--for liquids J6 in. openings. Other sizes of openings furnished when specified, prices on appli cation. Made in sizes from in. to 3 in. inclusive with screw connections. Cutaway view of Anderson strainer 1411 I Heating Systems specialties Armstrong Machine Works 851 Maple Street, Three Rivers,'Mich. Steam Traps .. . Air Traps . Humidifiers High Side Floats ... Refrigerant Purgers Representatives in Principal . ' Centers ARMSTRONG INVERTED BUCKET STEAM TRAPS Armstrong offers a complete line of traps for draining low and high pressure steam headers, pipe coil radiation, unit heaters, air conditioning equipment, process equipment, etc., to gravity or vacuum return systems. Automatic Air Discharge. Standard traps automatically discharge normal amounts of air along with condensate. Where large amounts of air must be vented quickly when steam is first turned on, Armstrong. BLAST Traps with thermic bucket vents are recommended. Air handling capacity, ranges from 500 to 1500 cu ft free air per hour. NEW! Traps with integral strainers save-fittings, labor. No. 880 with same capacity as No. 800 listed below is $11.50. No. 881 with same capacity as No. 811 is $16.00. Both cost less than traps plus separate Btrainers. . Capacities, Prices, Dimensions Note that capacities of No. 811, 812 and 813 traps are the same as No. 211, 212 and 213 respectively. On most installations, the engineer therefore has a choice of side inlet--side outlet or bottom inlet-- top outlet body styles. jvo Side Inlet Traps No. 800 No. 811 No. 812 No. 813 Pipe Connections........................... List Price (Regular)...................... List Price (Blast Trap)............... . Telegraph Code (Regular)........... Telegraph Code (Blast Trap)-- Height............................................. Diameter ....................................... Number of Bolts............................ Diameter of Bolts.......................... Weight.................................... ......... Maximum Pressure, lbs................ Continuous dis charge capacity in lb of water per nour at pressure indi cated. For more complete informa tion see the Capa city Chart in Arm strong Steam Trap Book. 5 10 15 20 30 50 70 100 125 150 200 250 Bottom 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 Bolta........................ Weight.................................... . Maximum pressure, lb.............. M'ortf'l H' or H` M'orX' X' or 1' No. tn-sie $10.00 $14.00 $23.00 $31.00 $12.00 $16.00 $26.00 $34.00 Aloe Brown Cherry Dawn Aloette Brownette Cherette Dawnette W ox* Z%" X' 5' 5' 6M' 7X' 6666 Mm 5 lbs. 150 450 560 640 690 500 580 660 640 680 570 X' 6 lbs. 250 830 950 1060 880 1000 840 950 860] 950 810 860 760 No. 211 H' $13.00 $15.00 far 4V|' X' 6 6 lb 250 X' H' 15 lbs. 250 27 lbs. No. 800-813 250 1600 1900 2100 1800 2050 1900 2200 1800 2000 1500 1600 1300 2900 3500 3900 3500 4000 4100 3800 3600 3900 3500 3200 3500 4800 5800 6500 6000 6800 6300 6000 6200 6700 5700 5300 5700 7600 9000 10000 8500 9800 9000 9200 10400 10900 9500 9200 7000 No. 212 No. 213 No. 214 No. 215 X'orX' X'orX' $21.00 $29.00 1' $41.00 1# or \Mm $55.00 $24.00 $32.00 $44.50 $60.00 Walnut Hemlock Larch Birette Walette Hemlette Larette 8* *8? 12X' 14# 5' w 8M' X' 8 12 lb 250 H' 6 21 lb 250 X' 8 34M lb 250 i W 8 47 lb 250 1412 14500 17300 19200 18500 18000 18200 18300 18000 20000 18500 17500 19000 Armstrong Machine Works Heating Systems Specialties High Capacity, Compact Size. The high leverage of the patented free-float ing lever makes it possible to open dis charge orifices which are very large for over-all trap size. Positive Action. The discharge valve is either wide open or closed tight. Fast opening and closing prevent wire-draw ing. Self-Cleaning. Swirling actionof con densate during discharge carries dirt through trap. There are no dead spots for dirt to collect. High Quality. 18-8 stainless interior parts. Valve and seat are chrome steel, hardened, ground and lapped. Low pressure trap parts same material and quality as those used for 1500 psi, 900 F. Armstrong Steam Trap Book. 44 pages of data on traps, selection, instal lation and maintenance. A usable hand book for any engineer dealing with traps. Free copy on request. TRAPS FOR UNIT HEATERS Armstrong inverted bucket steam traps are particularly suitable for drain ing low or high pressure unit heaters to vacuum or gravity return systems for these reasons: 1. Air and CO, are vented automati cally each time the trap opens--keeps heaters hot, helps prevent corrosion. 2. Condensate discharges at steam tem- Eerature as it accumulates--keeps eaters at maximum temperatures. 3. No build-up of back pressure in return lines. _ 4. Armstrong traps seldom require maintenance. A Bulletin with Btu output figures for 24 makes of unit heaters explains how to select traps. Available upon request. ARMSTRONG STEAM HUMIDIFIERS For Stores, Offices, Hospitals, Factories, Laboratories SOLENOID VALVE OPEN IT HIMXNSTAT CALLING FOR MOISTURE Operation- These units provide auto matic, closely controlled humidification by introduction of steam directly into the atmosphere. Installation is com parable to that of unit heaters. Steam at 15 psi or less is required. A solenoid discharge valve on the hu midifier is controlled by a sensitive strong Humidifiers is as much as 80 per cent less than some types of equipment. humidist&t. A fan mounted on the The small C-2 unit lists at $182.25 com humidifier aids in steam dispersal, or a plete with fan and motor, humidistat, venturi nozzle can be supplied. Where strainer and steam trap. Operation, us an electric spark might represent an ex ing steam at around $1.00 per ton, is plosion hazard, compressed air operated economical. There is no extra load on models are available. In addition to the heating system. No dripping--any the unit humidifier illustrated, there is moisture in the steam is re-evaporated a large model for installation in large air in the steam-jacketed separating cham ducts and central heating systems. ber. Control is accurate within a few Capacities range from 31 to 630 lbs of per cent R. H. steam per hour. Bulletin No. 1773 gives complete data Advantages. Installation cost of Arm- on required relative humidities, selecati!o__n__a__nJd i_n___sAt-a1l1l-a1t?io- n- oef XHT umid*if"iers. All Armstrong products are sold on a basis of satisfaction or your money back. 1413 Heating Systems specialties Carty & Moore Engineering Co. 1150 W. Baltimore Ave. 1919 ' - 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 sayings in labor due to the quick-mounting features. . Modd No. tf Bottom Hung 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 simple ad justments required to hang any particular type of radiation. Preparation of a O & 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 stock them six in an attractively-labeled carton. Shipping weight approx. 3} lbs. Tins bracket is also available with double hook and rein forced frame for double row wall radiation--specify No. 222. Model No. 33--A completely assembled top hung bracket Modd No. Bottom Hung Brackets 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 fressed steel stampings for } in., } in., in. and i in. nuts. A long travel slot permits ample adjustment yet the nut cannot pull out and the wide wingspread allows the insert to become deeply imbedded in the concrete so it cannot tear out under heavy strain. 50-} in. or } in. packed in a nicely-labeled carton-- 25-| in. or } in. 1414 Heating Systems C. A. Dunham Company DunHflm Heatlng'systems'and equipment 400 W. Madison Street, Chicago 6, HI. In.Canada: C. A. Dunham Co., Ltd., Toronto In England: C. A. Dunham Co., Ltd., London CONVECTOR RADIATION lotoer inlet grilles and in Recessed type Designed for use with hot water, or steam. Casings are No. 18 gage steel with removable fronts, and heavier gages for institutions. Dampers op tional. Capacities with steam at 1 lb, entering air at 65 deg F: 10 to 128 EDR. Cabinet dimensions: 4 to 10 in. wide; 18 to 64 in. long; 20, 24 and 32 in. high. Wall Cabinet Convector; ateo available n Sloping Top type Heating element of copper or aluminum fins on seamless drawn round copper tubes brazed to bronze headers; for working pressures up to 150 lbs. Tubes expanded after assembly to assure positive, permanent contact with fins. Heavy side plates protect fins from damage. BASEBOARD RADIATION For forced hot water, steam or vapor " heating systems. Baseboard consists of front and back enclosure sections of heavy gage sheet steel plus Dunham finned heating element. Enclosure sec tions are shipped in 10-ft lengths for cutting on job. Assembled by slipping front sections over flanges of back sec tions. Front sections are removable and are formed so that warm air is directed away from walls. Can be painted. Individual room dampers are optional. Finned heating elements available in 1 to 6 ft. lengths. FIN-VECTOR RADIATION New design. Extremely compact, light in weight, requires few supports, is easy to handle and assemble. Full range of sizes of covers and beating elements reduces Sloping Top Fin-Vector on-the-job cutting. Tube ends designed for fast assembly; covers formed for quick, simple joining. Covers and ele ments made in lengths from 2 ft to 10 ft in 6 in. increments. Covers in three styles: sloping top, flat top and expanded metal . . . each for one, two or three tiers of heating elements. Elements: tubes expanded into fins, no solder bond used. Tubes: seamless steel, 1H in. and 2 in. IPS; copper, in. nominal. Fins: 3} in. X 3M in. and in. X i}4 in. with rounded comers, fins spaced 24, 32 and 48 per lineal foot. 1415 C. A. Dunham Company i- Heating Systems dJShmTot DUNHAM UNIT HEATERS Horizontal Discharge Type Type V. Supplies proper volume of air at reasonably low out let temperatures. Available-in two models--H and HM. HM model, having less fin surface and lower final tempera tures, is for higher steam pressures. Sturdy steel case as sures maximum rigidity and freedom from vibration. Fur nished with constant-speed, two-speed or multi-speed motors. Manufactured in 11 sizes. Capacities at 2 lb steam, 60 deg entering air: 15,600 to 360,000 Btu per hr. Type V Heater Type C Heater Vertical Discharge Type Type C. Discharges air stream verti cally downward. Outlet temperatures relatively low. Volume of air kept high to promote uniform heat distribution horizontally, as well as to equalize tem perature differences between floor and ceiling. Four types of diffusers avail able. Heating element of non-ferrous mate rials. Fins are copper or aluminum. Tubes are heavy copper--expanded into fins to provide a positive permanent mechanical bond--then silver soldered into cast bronze or copper headers. ' Manufactured in 7 sizes. Capacities at 2 lb steam, 60 deg entering air: 32,800 to 492,000 Btu per hr. Wall type heater Blower Unit Heaters Type R. Available with mixing damp ers, by-pass dampers and filter sections for heating and ventilating large areas, ` or for heating only. Belt-driven centrifugal type blower fans use constant speed 1750 rpm motors on 60 cycle or DC current. Fans are double width, double-inlet type with forward pitched blades. Self-aligning, dustproof ball bearings support fan shaft. Heating element is replaceable tube type. Brass clamping nuts securely fasten seamless drawn copper tubes into semi-steel cast headers. All essential parts readily accessible, and can be re moved through either end of heater casing. Working pressure: up to 150 psi steam. Capacities at 2 lb steam, 60 deg enter ing air: 105,000 to 822,500 Btu per hr. Floor type heater with mixing damper. Also available with donyaied nozzles. 1416 Ceding type, healer C. A. Dunham Company Heating Systems frays0'165 DUNHAM HEATING SPECIALTIES Radiator Traps For all types of low pressure steam heat ing systems up to 25 lbs gage. Dunham design assures freedom from clogging; thorough draining of radiators by grav ity; minimum wear on parts. Body and cover of cast bronze; disc of Monel metal. Round, slightly raised valve seat minimizes depositing of incrustrants. Size 1E 2E 3C Pattern AP SW RH LH VST AP SW AP Tapping w U' 1* Cap. Sq Ft EDR 200 400 700 Thermostatic Steam Traps Operate in response to pressure caused by partial vaporization of liquid within thermostatic disc. Permanent adjust ment for correct operation built into trap at factory. Body, cover, union hut and nipple are brass. Valve and seat are special heat-treated stainless steel. Spherical valve is swiv eled to insure tight seating without causing localized stresses on disc. Ex ceptionally large valve opening permits ready passage of water or dirt. For 5 to 100 pounds working pressure-- Made in in., i in. and 1 in. sizes, for capacities from 125 to 1780 lb Cond./hr. * Ratings are based on 14 lb condensation per sq ft of EDR per hour and a iJ4 lb pressure differential.. Thermostatic Steam Trap Type TH-1A Float and Thermostatic Traps Especially adaptable for service as a drip-trap for dripping ends of steam mains, unit heaters and all types of heat exchangers. Capable of handling large amounts of air and water. Float is made of copper. Float valve and seat are Monel metal. Body can be removed for inspection of working parts without disturbing piping connections. Operat ing pressures up to 15 psi gage. Sizes: in., 1 in., 1)4 in., 1)4 in., and 2 in.; respective capacities: 800, 2000, 4800, 9600 to 20,000 EDR at 14 lb condensate per sq ft per hr with 2 lb pressure differ- Float and Thermostatic tial. Series 31 closed float traps avail- Trap, Seriee so able in same capacities. Inverted Bucket Trap Inverted Bucket Traps For venting air arid draining water from high pressure steam lines, heat exchangers, sterilizers and processing equipment. Traps increase heat transmission efficiency and hold equip ment capacity to a maximum. Body and cover of high tensile iron castings. Valve and seat (renewable and interchangeable) are special hardened, corro sion-resistant steel. Sheet copper bucket. Capacities range from 400 lbs to 5600 lbs of condensate per hour. Operating Pressures: 20 to 150 lbs gage. Sizes: Type OBS and ?4 in. Type OB )j> to 1)4 in. inclusive. 1417 C. A. Dunham Company Heating Systems fS"tles - DUNHAM HEATING SPECIALTIES Valves "Oriflex" Valves Self-contained, adjustable,orifice valves, packless bellowstype for proportioning steam supply to each radiator. Valve- need not be disconnected to make adjustments. Merely remove handle, insert key on adjustment stem and turn orifice to desired setting Sizes: $ and f in. '*Orifiex" Valve, Type J76 Packless Valves Pacile&s Valve, Type 1140 For all types of low pressure steam heating systems. Body and bonnet are brass castings. Heavily constructed brass union nuts and nipples. Phosphor-bronze bellows sealing member gives maximum resilience and wear; prevents leakage; keeps steam, water and dirt from clogging and corroding spin dle nut and. screw. Non-rising stem. Heat resistant com position handle. Sizes: to 1$ in. inclusive. . Spring Packed Valves For low pressure steam heating services. Body is brass casting, rough finish. Heavily constructed brass union nuts and nipples. Non-rising stem. Valve opens fully on less than one turn--dial shows direction and amount of opening. Heavy spring keeps constant pressure on special graphite asbestos composition packing to maintain tight seal around valve stem. Sizes: to 2 in. inclusive. Dunham Pumps Vacuum Pumps Type VR, Model B Pump, for capacities from tSfiOO to 65,000 EDR, Type VR, Model C Pump, for capacities up to tQpOO EDR, Furnished as single (Type VR) or duplex (Type VRD) units. Separate accumulator tank available for handling low returns. Each pump has own con trol panel wired through to motor. Pumps efficiently maintain desired vacuum range on return lines and deliver condensate direct to low pressure boiler. Selector switch on panel permits pump to operate on fully automatic, continuous, or float control. . Condensation Pumps Complete, compact assemblies for au tomatically returning condensate to boilers for gravity heating systems or steam process equipment. Also manu factured as Boiler Feed Pump. Type CHV--Single and Duplex--3450 . rpm for pressures up to 20 lbs. Capaci ties 2,000 to 10,000 EDR. Low priced pump. , Type CH--Model D, Single and Duplex Single Condensation Single Condensation Pump, --1750 rpm for pressures 50 lbs and lower. Pump,TypeCHV TVpe CH (CHH) Capacities 2,000 to 50,000 EDR. Rugged _____ pump for heavy duty applications. Type CHH--Model D, Single and Duplex--3450 rpm for higher pressures up to 70 lbs. Capacities 2,000 to 50,000 EDR. Rugged pump for heavy duty applications. 1418 C. A. Dunham Company Heating Systems ifS^E^ipment DUNHAM HEATING SYSTEMS Vari-Vac Differential . Cuts fuel costs up to 40 per cent. . required by utilizing a continuous flow Dunham Vari-Vac Heating Systems of steam at temperatures that vary with save up to 40 per cent on fuel costs the weather. For every size or type of . . . because Vari-Vac automatically building regardless of location or cliprovides the precise amount of heat matic conditions. "Supreme" job. Tape RSTT Control Equipment. Metro "Single Riser" Costs less to install, to maintain, to operate-- Provides an uninterrupted path for flow of steam from top to bottom of building. Continuous pipe runs down through overlying rooms ... is offset in each room into a convector or baseboard radiator. ` 1. Eliminates all radiator branches. 2. Eliminates all traps and valves in occupied quarters. 3. Eliminates costly furring of ma sonry walls. . 4. Eliminates expansion joints. 5. Eliminates settings for temporary heat. For complete catalog data on Dunham Products and Equipment write C. A. Dunham Company, 400 W. Madison St., Chicago 6, Illinois. 1419 Heating Systems Steam and Hot Water Hoffman Specialty Company General Office and Factory , 1001 York Street, Indianapolis 7, Ind. Sales Representatives in Principal Cities .. Manufacturers of Radiator Air Valves, Quick Vents and Air Eliminators for all types of Steam and Vacuum Heating Systems--Steam Traps of all kinds--Radiator Supply Valves--Vacuum and Condensation Pumps--and Hot Water Automatic Heat Control Systems. , RADIATOR AIR VALVES FOR STEAM AND VACUUM SYSTEMS No. i0 No. H No. i3 No 70A No. 71A No. IA No.lA No.S and No. 46 No. 40 Steam--Hoffman patented tongue syphon--Y in. connection--fixed port. No. 41, 43 and 45 Steam--Straight shank for convectors--telescopic syphon--Y in., Y in., and J4 in. male, Y in. female connections. No. 70A Steam--Tongue Syphon--Non-adjustable, single port--Y in. connection. No. 71A Steam--Straight shank for convectors--telescopic syphon Y in. connection. No. 1A Steam--Tongue Syphon--ADJUSTABLE air opening--Y in. connection. No. 2A VACUUM--Tongue Syphon--ADJUSTABLE air opening--Y in. connection. No. 3 Steam--For Airline or PAUL systems--Y x Y in. conn.--union tailpiece. Hoffman Specialty Company Heating Systems h"w.^ LOW, MEDIUM AND HIGH PRESSURE THERMOSTATIC TRAPS Low Pressure Medium Pressure High Pressure Low pressure traps have brass bodies, caps and union nut and tailpiece. 17C is made in Angle, Swivel and Vertical patterns. 8C 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 15 lb pressure Y in. connection . No. 8C Capacity 400 sq ft EDR 25 lb pressure Y in. connection . No. 9C Capacity 700 sq ft EDR 25 lb 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. Y in. 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. Capacities--Lb Condensate per Hour--Working Pressure--Lb per Sq In. Gage Traps 0880 % A' A' r 5 15 25 50 Traps 100 125 180 225 235 300 400 490 88HH H' A' 225 350 450 650 SH 325 500 625 850 9H H' l6 25 50 100 125 235 400 560 590 300 490 650 720 450 650 875 950 625 850 1125 1250 FLOAT TRAPS, DIRT STRAINERS AND SUPPLY VALVES No. 4 SteamMains--Will not close against water--% in. male, Y in-female connection. No. 4A Steam Mains--Float closes against water--% in. male, Y in. female connection. No. 16A VACUUM Mains--Float closes against water--M in. male, Y in. female con- UCUIlU/ll, .. No. 75 SteamMains--Medium systems--has float--%in.male,^in. female connection. No. 76 VACUUM Mains--Medium systems--has float--% in. male, M in. female CUUUWUUll. No. 75A Steam Mains--Large systems at low pressure--has float--% in. , male, .Y..ln- female connection. .. No. 76A VACUUM Mains--Large systems low pressure--has float--Y in. male, Y m- female connection. No. 74 Unit Heater Vent Valve--Operates 0 to 35 lb. Vents air at any pressure and whether rising or falling--can De used on steam mains--Y in. male, Y in. female connection. .. No. 79 Hot Water Vent Valve--Positively removes air from piping of any hot water system. Max. pressure 75 lb--Y in. male, Y in. female connection at base and tapped at top for Y in. pipe connection. 1420 50 Series Float and Therm. Traps are available in large capacities and four pressures, 15,30,60 and 125 lb. Used for venting and draining risers, steam mains, unit heaters, blast coils, etc. 50 Series Traps are made for easy servicing with all working parts mounted on cover. Remove four bolts to expose all parts. Pipe sizes are from % in. to 2 in. Radiator Supply Valves are made in sizes from Y to 2 in. in Angle, R.H., L.H., and Straightway patterns. Brass bodies, union nut and tailpiece. Nos. 180 and 185 have non-rising 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 Y 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 200 lbs. Vacuum Pumps Single and Duplex Units for different Capacities and Sizes Condensation Pump Single and Duplex Units for different Capacities arid Sizes 1421 Hoffman Specialty Company Heating Systems . Steam aad Hot Water 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 of 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. . ' W 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. Circulating Pipe Orifice A calibrated orifice used to balance the circuits through the boiler and through the Hoffman circulating pipe. Hot Water Control Valve . _. Opens only sufficiently to supply the correct amount of water to maintain the proper water temperature being circulated through the system. Thermometer. Should be installed about 6 in. from submerged 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. - 1422 Hoffman Specialty Company Healing Systems H1"waft HOFFMAN PANEL-FLO VALVES for adjusting the Sow 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 cutilow through coil as much as 60 per cent. . . WITH NO APPRECI ABLE CHANGE IN CIRCULATING PUMP HEAD. Has indicating Dial for accurate setting of each coil--or adjusting any coil withoutaffectingtheother coils. % in. pipe connection. 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 PRESSURE RE DUCING VALVES Series 710 Max. Press. 250 psi., Low Press. 5to80psi. Series 700 Max. Press. 200 psi.. Low Press. 1 to25 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. Series 7to Series 1100 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. Hydraulicajly formed bellows of selected material. Rugged construction. For water heat ers, convectors, fuel oil preheaters and other similar appli cations. 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 Yi 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. Hlustrated. are two popular control units, typical of the complete Hoffman line. . 1423 Hot Water Limit Control Immersion Type Heating Systems steam ILLINOIS ENGINEERING COMPANY General Offices and Factory: Chicago 8, 111. 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 --Types A&M 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 gjieam 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 steam at low positive pressures without any pump or mechanical vacuum producer. Recom mended for Residence, Small Apartment, and similar service. Gives rapid, flexible steam circulation. Illinois Float and Thermostatic Traps--Unsurpassed for draining ventilating units, 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 and 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. 1424. Heating Systems steam ILLINOIS ENGINEERING COMPANY General Offices and Factory: Chicago 8, HI. Representatives In Principal Cities Fig. S60 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 TrimFig. 121--Furnished in either single seat or double seat type as service requires, for the control of steam, air or gas. Con trol 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, Fig. 71. . ;. Non-return Valves--Fig. 260--Placed between boiler and header to prevent return of steam to boiler. Sensitive in operation. Extra heavy semi-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, warming 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 alvxiys 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. . I i (; Series HG t 1425 Series SO i Heating Systems Steam and Hot Water Maid-O'-Mist, Inc. 3217 No. Pulaski Road Chicago 41 rill. 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 autofmatic venting of the air which causes j circulation trouble and heating waste.. More and more, contractors who value satisfied customers are installing these l trouble stoppers. No. 7 Auto-Vent. For mains, pipe lines, unit heaters, convectors, coils, etc. De signed for vertical mounting only. Size No. 7 Avto-Veni 4% in. x 2J4 in- with in. I.P. female connection. Made of brass and equipped with a self-closing, float operated valve. 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 }4 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. No. 27 Auto-Vent No. 7 Auto-Vent For venting convector radiators For convectors and free standing radiation. Designed for horizontal mounting only. Size 3 in. x in. with J-jj I.P. female connection. Construction and internal working parts are same as in No. 7 Auto-Vent, but for horizontal mounting. Made of non- ferrous 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. 1426 7 Maid-O'-Mist, Inc. Heating Systems' Steam and Hot Water No. 67 Aulo-Vcnt No. 67 Auto-Vent For convectors and baseboard radiators. Designed for vertical mounting only. Size 3Jie in. x 1M in. with a H 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 No. 72 Auto-Vent For convectors, baseboard and free standing radiation. Designed for both vertical and horizontal mounting. Size V/a in. x H in. with % in. I.P. male con nection., No. 72 Auto-Vent is fast vent ing valve of the expansion type. All For convector radiators expansion and contraction of the single, non-porous, composition disk is confined to four port veqts. Internal siphon tube prevents water logging when installed in either .vertical or horizontal position. Immediate drainage means fast disk dry ing, quick venting cycle. Air in system enters valve and passes No. 71 Auto-Vent through the vent port to the atmosphere. Water following same path comes in contact with disk, which swells, closing ports. Entrapped air contracts disk and venting cycle is repeated. Cycle 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. No. 14 and No. 15 balancing valve UNIT-- Balancing Valve Adapter Units for Hot Water Heating Systems Maid-O'-Mist Valve Adapter Units make any copper, bronze, or cast iron tee a For baseboard radiation balancing valve. Stocks of expensive square head cocks or valves no longer needed. These units, quickly soldered or sweat fitted into No. u No. 15 copper and bronze tees or threaded into cast iron tees, regulate hot water flow through radiators, convectors, baseboard panels, radiant coils, return mains, and branches. Can be inserted in side outlet or run of tee of same pipe size to complete either a straightway or angle balancing valve. Precision made of non- ferrous metals. Simple balancing requires only a screw driver. ' 1427 I ^ Heating Systems vaSraUes Jas. P. Marsh Corporation Dept. 5, Skokie, Illinois 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 Packleee 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. Jas. P. Marsh Corporation Heating Systems *1$%^ 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 75 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 seat 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 and extreme duty. Marsh Electrimatic Solenoid Valves are made in both direct-acting and pilotoperated types in %, % in. and Vi in. or 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. 1429 i V Heating Systems 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: Albant, N. Y. . Atlanta, Ga. Baltimore, Md. BZBMZNGHAM, Ala. Buffalo, N. Y. Chicago, III. Cincinnati, O. Cleveland, O. Denver, Colo'. Des Moines, la. Detroit, Mich. Evansville, Ind. Fort Wayne, Ind. Fobt Worth, Tex. Frederick, Md. Gbbenebobo, N.C. Houston, Tex. Indianapolis, Ind. Kansab Cmr, Mo. Los Angeles, Cal. Mexico, Dj. Miami Springs, Fla. Milwaukee, Wis. Minneapolis, Minn. Mobile, Ala. Montheal, Que. Needham, Buss. New York, N. Y. Oak Ridge, Tenn. Omaha, Neb. Orlando, Fla. Pun.ADELPtnA, Pa. Pittsburgh, Pa. Ponca City, Okla. Portland, Me. Portland, Ore. Richmond, Va. Rochester, N. Y. Salt Lake City, V. San Francisco, Cal. Seattle, Wash. Spokane, Wash. St. Louis. Mo. Sumter, S, C. Syracuse, N. Y. Toronto, Onfc. Tucson, Arizona Vancouver, B. C. Washington, D. C. Yakima, Wash. STEAM, WATER, AIR, OIL AND GAS SPECIALTIES TRAPS Thermostatic: Steam, to 2251b. Expansion: Steam, to 2501b. Weight-Operated: Steam, Air, Gasoline; to 1500 lb. Piston-Operated: Steam, to 650 lb. Radiator: to 15 lb. SEPARATORS: Steam, Air, Gas to 250 lb. STRAINERS: to 600 lb. VALVES, Cylinder Con trol: Air, Gas, Oil, Steam, Water; Lever, Foot, Solenoid, Motor- Operated ; 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 Jot Every Heat, Power and Process Application A survey of large users of Nicholson industrial steam traps showed these main reasons for the increasingstandardization on Nicholson units for specified appli cations: 1) Operate on lowest possible tempera ture differential; no waterlogging. 2) Have 2 to 6 times average drainage capacity. 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 450 Max. Capacity In Lbs per Hr. at Various Pressures--Types A, AHV, AU Size, inches Ji-H--H X 1 1 lb. 865 865 1020 2 lbs. 1220 1220 1440 5 lbs. 1915 1915 2270 10 lbs. 2695 2695 3190 15 lbs. 3290 3290 3900 20 lbs. 3780 3780 4475 40 lbs. 5290 5290 6250 50 lbs. 5885 5885 6955 Size, Inches M--H--yi X1 60 lbs. 6400 6400 7590 80 lbs. 7310 7310 8660 too lbs. 8120 8120 9600 125 lbs. 8925 8925 10,570 150 lbs. 9775 9775 11,590 175 lbs. 10,400 10,400 12,310 200 lbs. 11,090 11,090 13,100 See Note A p. 2 LIST PRICES--TYPES A. AHV, AU TffpeAU Size, Inches K-K-M H l 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 Inches hi' %r . 1430 W. H. Nicholson & Company Heating Systems Specialties Nicholson Industrial Steam Traps, Types B and C Size 1 lb. 2 lbs. 5 lbs. 10 lbs. 15 lbs. 20 lbs. 40 lbs. ! 4^ " ! 1695 2120 3200 1610 2385 2985 4510 2530 3760 4700 7100 3560 5290 6610 9990 4350 6450 8070 12,200 4990 7420 9260 14,000 6980 10,350 12.960 19.600 martiMUM CAPACITY IN POUNDS PER HOUR AT VARIOUS PPVdCnptny-- H" Ye" i --IK' lK'-2 80 lbs. 9660 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 50 lbs. 60 lbs. 7775 11,640 14,430 21.800 8460 13,660 15,710 23.750 CAST STEEL 250 lbs. 300 lbs. 16,090 23,870 29,850 45,150 17,400 25,820 32.300 48,900 jTvse m vapacmes snown 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 operation?, select traps to handle not more than 50 per cent of capacities shown; Types B and C are for pressures from vacuum to 225 lb; cast iron, aluminum painted. Type C is also furnished in cast steel, with stainless steel bellows, for pressures to 300 lb with super heat up to 500 deg total temperature. For complete details, BULLETIN 450. LIST PRICES. TYPES B AND C Type B Size, Inches i- r . Type B Cast-Iron With Bellows of Bronze Monel Stain less $25.85 $29.20 $33.70 33.90 38.30 45.25 40.40 43.95 50.15 59.80 64.45 71.10 Type C Cast Iron With Bellows of Cast Steel With Bellows of Bronze Monel Stain less Monel Stain less $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 53.70 63.00 91.00 $45.45 60.30 69.65 97.65 Valve Orifice, Inches K' & K' jiyues a, tiu ana t. 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 " 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, SeriatA --------- vapor and vacuum; r and 1-hand comer types for 200 sq ft. Pressure to 15 lb. BULLETIN 744. 1- Series 2A 2R & 2L 4A Size K' K K List Price $5.30 6.00 7.95 A 2K' 2K 3K B 1M' H c 2K' 3kt 3H D 2K' 2H' 2H' E IK' Weight CAPACITIES IN SQUARE FEET EDR SERIES AND SIZE H'-2A, 2R & 2L 1 K'-4A | PRESSURE DIFFERENTIAL--LBS. PER SO ram K H i IK 2 S 10 15 85 120 165 200 235 370 530 640 165 230 330 400 465 730 1050 1300 ..-- --luMajnamoi wnn recommended standards of Steam Heat %nti.llthZtA`an' ScU*t.tMnV,Pp dUUirCeCctUlyy fWrom table for the lowest pressure diL Xfeerreenntttiali that masvy exist min the styrsateum. * 1431 i ' Heating Systems specialties Ohio Brass Company MANSFIELD, OHIO EOUJfe^TEMP Versatile New Radiant Heat Valve If a Provides balancing, tight shut-off, venting, draining and thermometer well all in one valve. 1. ADJUSTABLE FLOW--Easy adjust ment of flow for balancing. Full open to tight shut-off possible. 2. ABSOLUTE TIGHT SHUT-OFF-- Valve can be shut off completely by a VENTING OR DRAINING 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 key from above. .. 90 deg turn of stem. Synthetic rubber "O" ring on disc insures a leaktight closure. 3! BUILT-IN THERMOMETER WELL Figure t O Figure S --O-B EQUATEMP has a thermometer well drilled into the stem, providing a handy means for accurate balancing. 4. TAMPERPROOF CONTROL--- EQUATEMP settings require three sep VENTING OR DRAINING IN INVERTED POSITION Figure 3. Automatic vent installed in bottom drain. Figure 4. Top drain plug removed for draining' of system. Valve may be operated with key from below. arate Allen-type wrenches* (not nor mally available in the home). Same wrenches fit all size valves. 5. vfiRIABLE 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 S Figure 4 6. EQUATEMP MANIFOLD FITTING --Available with three or four outlets. May be combined to form manifolds of any desired number of valves. * Handy key furnished with each 24 valves. ROUGHING-IN DIMENSIONS COPPER-TOTOPPF.R Nn. 37 p H A Bc 1% m IX 2% -H 2& 3M li SCREW TYPE No. 38 Avail- A B c able X 1 % m 3 18 2% m 2 2% m 2H For additional information, please write to Ohio Brass Company, ` Mansfield (1), Ohio, for EQUATEMP Folder. 1432 D lM 2% i Heating Systems Hot water Sarcotherm Controls Inc. Empire State Bldg., New York 1, N. Y. Representatives in Principal Cities, Factory at Bethlehem, Pa. Sarcotherm Control for Hot Water and Radiant Healing System. Fully automatic and completely inte grated control systems for any type of heating, direct by outride temperature. 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. Type "[" Sarcostat Control for Steam Heating Syetem. 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 Engineering Staff on any proposed control system. There is no obligation. 1433 Heating Systems steam Sarco Company, Inc. Empire State Bldg., New York 1, N. Y. Branches In Principal Cities " SARCO CANADA LIMITED, 611 Gerhard St., E.,Toronto 8, Ont. 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 inproviding modern heating. SARCO RADIATOR TRAPS* Radiator Trap, Typo H Type H is the standard radiator trap tor 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 vacuum to 25 psi. Body and cap are of brass, standard brass finish; self-aligning valve head and re newable seat of hard bronze; union connection on inlet. In i in. size available in angle, straight or offset patterns, $ in. angle and straight, 1 in. angle only; also | in. and | in. vertical. Catalog HV-150. SARCO RADIATOR VALVES Radiator Valves Type V Type SM . Sarco offers two types of valves; bellows packless type 43 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 straights way patterns, wheel handles or lock shield. Also available for hot water systems. Bodies of all valves are brass, stand ard brass finish; outlet fitted with union connection; sizes i in. to 11 in. Catalog No. HV-160. 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 f" to 1". Also S-65 for pressures to 65 psi. Catalog HV-190A. Float-Thermoetatie Trap SARCO FLOAT-THERMOSTATIC TRAPS Sarco offers a wide selection of Float-Thermostatic Traps, i 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-450A. 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 i to 2 in. Catalog HV-S50A. . 1434 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-165. 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 central 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-170. 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 from 0 to 300 F. Catalog HV-600- Type TR-tt. Standard for hot water storage tanks, fan unite, 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-800. 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, iron or monel screens. Available in sizes J to 8 in. Catalog No. HV-tSOO. 1435 Heating Systems l^Sitie, Strong, Carlisle & Hammond Company Cleveland, Ohio "STRONG" The Complete Steam Specialties Line . - 56 1. Standard In-Line Traps (Semi-Steel). Inverted bucket type.' Hi-Cap design. Parts.on cover for easy removal without breaking pipe connections. All stain less parts. . Trap Pipe Size Continu- Capacity Weight No. (inches) ous at psi lbe/hr lbs 070 K, H 125 <90 3H 170 H. X 125 955 7 971 1 125 1230 7H List Price *7 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- X X X IX ix 2 2X 3 Weight lbe Sizes X-*n.t H-in. fur 1 nished with 60 x 50 2M mesh Monel cloth 3X screens. Sizes H-i- to 5H 3-in. standard with .027 8X perforated Monel. nx 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 Ibs/hr lbs 070-T X,X 30 660 3X 170-T H, X 30 1290 8 271-T H. 1 30 1780 9 . List Price $182..5000 17.50 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. . TraD Pipes Size Continu- No. (inches) ous at psi 171 X 125 80 X 125 181 X 82 125 125 83 84 . IX IX 125 125 85 2 125 Capacity Weight List Ibs/hr lbs Price 1230 7X $10.50 1700 16 17.00 3300 25 22.50 6100 35 30.00 10,200 64 37.00 15,400 82 55.00 32,000 117 73.00 5. Open Bucket Traps (Semi-Steel). For all steam service, and particularly suitable for pulsating pressures. Also for draining water or other liquids from lines on air or gas service. Anum-Metl seat guaranteed leakproof one year. Pipe Trap Size No. (inches) 30 X 31 X 32 1 33 \x 34 ix 35 2 36 2X Continuous Capacity at psi lbs/hr 125 1230 125 1560 125 2750 125 6100 125 8700 125 11,500 125 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 0.& K Pressure Regulators (Semi-Steel). For steam, air and gas. Direct operated. Rugged construction. Fitted with special laminated, phosphorbronze diaphragms and stainless valve and seat. Pipe Size No. (inches) Weight List lbs. Price Type O X% X Initial pressure to 225 8 psi, 400 F, reduced $15.00 Type K X ranges 0-200. Initial pressure to 225 15 19.00 (illus trated) X 1 IX IX psi, 400 F, reduced ranges from 0 to 85 psi. Type K has an inte gral strainer. 15 18 40 40 20.00 27.00 38.00 42.00 7. Type C Pressure Regulators (Semi Steel). For installations requiring ac curate and dependable regulation. Stainless trim, single-seated, pistonoperated, pilot controlled, spring-loaded. Pipe Size Weight List No. (inches) lbs Price TypeC >4 From initial pressure 17 $36.00 1X to 250 psi, 450 F. For 17 reduced pressure 17 39.00 43.00 \xIX from 0 to 200 psi. 40 46.00 40 48.50 *x2 Available in cast steel 48 series 30, 40 or 60 74 60.00 79.00 3 flanges; pressure 600 98 95.00 4 psi; temperature 750 150 160.00 deg. Complete Catalog Available on Request. Heating Systems * w.ter WARREN WEBSTER & COMPANY Pioneers of the Vacuum System of Steam Heating: : Since 1888 Main Office and Factory: 1731 Federal St. Camden 5, New Jersey REPRESENTATIVES Albany 6, N. Y. Columbus 15, Ohio Milwaukee 3, Wxs. Saginaw, Mich. *H. A. Bond R. A. Wilson A. M. Freeman W. A. Witheridge 152 Washington Ave. 20 S. Third St. Allentown-Easton, Pa. Dallas 4, Tex. 6088 PUmkinton Bldg. Minneapolis 3, Minn. 2340 Mershon St. St. Louis 3, Mo. E. Kessler Webster, Jr. J. R. Dowdell & Co. H. E. Gerrish Hester-Bradley Co. 1020 Highland Ave. P. O. Box 507 1111 Nicollet Ave. 85 Washington Ave. Bethlehem, Pa. - Davenport, Ia. Newark 2, N. J. Salisbury, N.C. Atlanta 3, Ga. H. H. Evanson Edward Mayr E. C. Shearon E. W. Klein and Co. 918 Kahl Bldg. 1060 Broad St. 529 S. Fulton St. 152 Nassau St.. N.W. Dayton 2, Ohio New Haven 10, Conn. Salt Lake City 4, Utah Atlantic City, N. J. *C. D. Weaver, Jr. H. R. Briggs Midgley- Huber *B. H. Strouse 1136 U. B. Bldg. 902 Chapel St. 44 W. 8 St., South 630 Guarantee Trust Bldg. Denver 4, Colo. New Orleans 12, La. San Antonio 5, Tex. Baltimobb 18, Md. *H. H. Herman W. H. Grant, Jr. R. 8. Ryden H. M. Harris 1228 California St. 209 Vincent Bldg. 403 Insurance Bldg. 2301 N. Charles St. Des Moines 9, Ia. New York 16, N. Y. San Francisco II, Calif. Birmingham 3, Ala. H. E. Drain J. F. Hanbury E. H. Goins Haydn Myer Co-, Inc. 506 Securities Bldg. 95 Madison Ave. 420 Market St. 2224 Comer Bldg. Detroit 2, Mich. North Hero, Vt. Seattle 9, Wash. Boston 10, Mass. A. B. Knight H. J. Clark W. W. Cox J. F. Tuttle Co. 8316 Woodward Ave. North Hero, Vt. 314 9th Ave. N. 127 Federal St. Grand Rapids 2,-Mich. Oklahoma City 1, Okla. Spokane 7, Wash. Brunswick, Maine Hero D. Brett F. X. Loeffler J. C. Kelly C. Claud Clark 331 Ottawa Ave. N.W. 1604 N.W. Fifth St. 2932 E. Trent Ave. . Box 476 Buvfalo 2, N. Y. Howard P, Asmus 502 Jackson Bldg. Butte, Mont. Sullivan Valve & Engr. Co. v 909 E. Second St. P.O. Box 1931 Chattanooga 2, Tenn. C. E. Mills 720 James Bldg. - Chicago 6, 111. ' P-. W. Stickney Harrisburg. Pa. Omaha 2, Nebr. Fred W. Scnimme) M. E. Wain ' 835 S. 13 St. 2311 Douglas St. Houston 1, Tex. Orlando, Fla. R. B. Johnson G. R. Macnam&ra 1017 Rosine Street Church & Main Bldg. Indianapolis 4, Ind. Philadelphia 3, Pa. *S. E. Fenatermaker. Karl Rugart 333 N. Pennsylvania St 26 South 20th St. Kansas City 8, Mo. Pittsburgh 22, Pa. *F. N. Scha&d , / R. B. Stanger 3252 Roanoke Road Empire Bldg. Los Angeles 13, Calif. Portland 4, Ore. Syracuse 2, N. Y. R. H. Bacon 214 E. Fayette St. Toledo 2. Ohio F. C. Richardson, Jr. - 402 Colton Bldg. Tulsa, Okla. Guy J. Griffin Loeffler-Greene . Supply Co., Box 1137 Washington 7, D C. H. S. Ivins 208 Hamilton Natl. 549 W. Washington Blvd R. M. Gunzel D. R. Munro Bank Bid Cincinnati 2, Ohio 320 Crocker St. 112 S.W. Pine St. Wichita 2. Kanb. *G. B. Houliston Louisville 4, Ky. Raleigh, N. C. Ray-F. Bauer 707 Race St. Clarke Kaye & Co. Allen-Still Co. 434 N. Rrck Island St. Cleveland 15, Ohio *A. L. Vanperhoof 519 Barret Ave. Memphis 3, Tenn. 1202 Newbern Ave. Richmond 19, Va. Wilkes-Harrb, Pa. A. H Roes 233 Hanna Bldg. Columbia, S. C. *T. J. O'Brien 1030 Exchange Bldg. L. A.Bernert Crenshaw Bldg. 303 Market St. Kingston, Pa. *R. F. Donovan P.O. Box 5204 401 Wildwood Ave. Milton, N. Y. (Near Poughkeepsie) Winfield C. Bailey Rochester 4, N. Y *L. M. Hakes 339 East Ave. Wilmington. Del. Wm. J. Robinson P O. Box 1501 . * Member of The American Society of Heating and Ventilating Engineers. Licensees and Manufacturers for Canada and Newfoundland: DARLING BROS., LTD., P, O. Box 187, Montreal, Caisda THE COMPANY Warren Webster & Company have specialized for sixty years in the field of steam circulation and steam distribu tion, particularly vacuum, vapor and low pressure steam heating of buildings, and medium pressure steam in industrial and process heating applications. Webster "true perimeter" forced hot water heating utilizes Webster Base board Heating, with or without Webster Continuous Flow Control. It is par ticularly suited for residences and other one and two-story buildings. The specialized experience of the Com pany is available through engineers at the Home Oflice and through the Repre sentatives listed above. Webster Repre sents! ives are prepared to supply on request full technical, availability and price information on all Webster Sys tems and Products. 1437 Warren Webster & Company ( Heating Systems Hot Water STEAM HEATING SYSTEMS Webster Steam Heating Systems are low pressure, two-pipe systems in which steam is delivered to radiators and other heating surfaces through supply piping and water of condensation and air are removed through separate return piping. Webster Radiator Valves and Thermo static Traps are installed respectively on the supply and discharge connection of each radiator. Webster thermostatic or float and thermostatic traps assure re moval of water of condensation and air from the piping. ' Available with vacuum return, or with open return (vented to the atmosphere) with either Condensation Pump or Boiler Return Trap and Vent Trap to return water to the boiler, or with Vent Trap alone where condensate is wasted to the sewer, or in appropriate small installations. Webster Vacuum System--A conven tional vacuum heating system in which the return mains are joined together and connected to the suction end of one or' more vacuum pumps which remove air and water of condensation and assists circulation by maintaining a lower pres sure in the return than in the supply piping. return is not possible, a Condensation Pump may be substituted for the Boiler Return Trap Combination. Webster Type~"V" System--Employs only a Webster Vent Trap. For instal lations of 1000 sq ft EDR or less with oil burner, stoker or gas burner; with vaporstat having cut-in pressure of about % lb and cut-out pressure of about M lb (not pressurestat), lockswitch or protec tor relay and one or more key room thermostats. Vent Trap at ample height above water level. Boiler Protector, or at least a low water cut-out. Ask for Bulletin. Webster Moderator Systems--These are all Webster Steam Heating Sj^tems with vacuum or open return to which are added (a) accurately sized metering ori fices in radiators and other heating sur-' faces to balance distribution and permit "partial filling" of all radiators practi cally simultaneously and at various fates of steam flow, (b) Automatic con trol by Outdoor Thermostat for varia tions in outdoor temperature, (c) Manual Variator to provide for convenient ad- i'ustments for heating up, reduced night eating, shut off, etc. Webster Type "R" System--A two- pipe, low pressure or vapor heating sys tem. Water of condensation is returned to the boiler by gravity, prompt return being assured regardless of variations in boiler pressure through the operation of a Webster Boiler Return Trap and Vent Basement installation of Webster Boiler Return Trap and Vent Trap for Vapor Heating, WAster Type "ft" System. ' Typical arrangement of WAster E-6 Moderator System. Trap in combination. Equipment is available in sizes to care for systems ranging from the smallest to 16,000 sq ft EDR. Where desired, or where gravity "E" Series Moderator Controls--In this series the Outdoor Thermostat and Variator position a motor-operated Steam Control Valve through an 1438 Warren Webster & Company Heating Systems |`watet Electronic Differential Pressure Control Cabinet to produce continuous steam delivery and nesting effect at the radia tors with automatic variation in heating for changes in outdoor temperature ana automatic adjustment to compensate for variations in steam supply pressure. Ask for Bulletin B-904A. "EH" Series Moderator Controls--In this series the Outdoor Thermostat and Variator may control a motor-operated steam valve or directly control oil or gas burner or stoker through a cycling Con trol Cabinet. Steam delivery is inter mittent but in short cycles so that heat ing effect is substantially continuous, particularly with cast iron radiation. Ask for Bulletin B-960. Control Valves---Main steam control valve, throttling type, maintains proper pressure differential control in the sys tem. Ask for Bulletin B-291. Motorized valves provide shut-off serv ice in steam or hot water heating, or throttling control in continuous flow hot water heating. Ask for Bulletin B-290. PERIMETER FORCED HOT WATER HEATING SYSTEMS Webster Continuous Flow Control--for forced circulation Hot Water Heating Systems. Outdoor Thermostat and Var iator control throttling-type valve or di rectly control oil burner, gas control or stoker motor. , Water flows continuously through .the system. Heating is con tinuous and adequate at all times. Ap plicable to Baseboard, Convector, Radi ator or Panel Heating. Ask for Bulletin B-200. Webster Baseboard Heating--A pat ented forced circulation hot water heat ing syBtem in which the heating element fits behind a specially built metal base board. Air enters at the floor line, passes over the finned heating element, is warmed and comes out of slots at the top of the baseboard. The heating ele ment is a copper tube with copper fins funning in a continuous loop around the exposed walls of the house--a separate loop for each floor. . Uses less material and less labor than conventional radiator heating systems, while providing all the advantages claimed for forced hot-water, plus radiant effect from warmed baseboards and walls/ plus natural convected air movement essential to comfort. Tem peratures vary less than 2 deg from floor to ceiling. Ask for literature. Diagram of typical installation of Webster Baseboard Heating in t story residence, showing: (1) Boiler; () Expansion Tank; (3) Circulator; (A) Pressure Reduc ing and Relief Valve; (5) Flo-Control Valve (If Re quired); (6) Webster Return Header Assembly Includ ing Purge and Balance Valve and Air Vent; (T) Webster Heating Element; (8) Reduced Heat Damper, or By-Pass (Optional); and (9) Expansion Loop. STEAM HEATING AND PROCESS SPECIALTIES Arrangement of Webster CF-9 Continuous Flow Hot Water Heating Control. Top, Outdoor Bulb; center, Control Unit with switch and Variator. Radiator Valves--Choice of spring re tained packing, Type BW-P or Sylphon Bellows Packless Series 600-S. in., AZ . in., 1 in., 1}4 in. sizes. In angle, right and left hand; straightway, with single or double union. Spring retained pack ing. For low pressure vapor and vacuum steam heating service. Ask for Bulletin B-705. 1439 Warren Webster & Company , . Heating Systems Steam Hot Water Thermostatic Traps--Series 7 and 5 for low pressure vapor and vacuum steam heating service, radiators and drips. H in., in., and 1 in. sizes. There are 6 body models in the i in. size alone. Maximum pressure, 25 lb per sq in. , Series 7 (diaphragm type) described in Bulletin B-702. Series 5 (bellows type) described in Bulletin B-701. Series 78 for discharge of air and water from heating coils of any apparatus using steam at pressures up to 150 lb per sq in. J^in., A in., % in., and 1 in. sizes. Ask for Bulletin B-1200. Heavy Duty or Drip Traps--Series "26" Float-and-Thermostatic for heat ing and air conditioning. Most used sizes: 00026, 0026, 026. Pressures up to 15 lbs per sq in. Made for the pressure and capacity conditions encountered at all drip points. Series "79" Float-andThermostatic for process. For pressures up to 150 lbs per sq in. For use where large volumes of hot condensate must be handled more quickly than is possible by thermostatic traps alone. Ask for Bulle tins. Strainers--Dirt: lA in. to 6 in. sizes. Maximum working pressure 150 lbs per sq in. Placed ahead of traps in return lines of steam-using equipment and steam heating systems to catch dirt and other particles, preventing them from impairing the tightness of the traps. Suction: Maximum working pres sures 15 lbs per sq in. Installed ahead of vacuum pump to prevent dirt from damaging pump. Ask for Bulletin B-709. . metal front or free standing floor cabinet. Contained within the enclosure in a pre fabricated unit, combining heating sur- Wall-to-wall application of Webster Walvector. Inset, Webster System Convector Radiator* face, valve, trap and uniono cnnections, shipped ready to connect to supply and return piping. Webster System Radiation was first offered in 1932. Now, available in an improved design, using the same basic material, copper tubing and aluminum fins. Increased rigidity of the tubing and the development ofa new method of manufacturing has produced a fin surface of unusual rigidity, free of expansion and contraction noises. Ask for Bulle tin B-1500. Webster Walvector--Elongated, nonferrous convector. Heating element is made up of a specially. annealed cop per tubing with rib-reinforced, square pressed aluminum fins. Available in two fin sizes: 3 in. fin size in 2, 3, 4, 5 and 6' ft; 4 in. fin size in 2, 4, 6 and 8 ft lengths. Boiler Protectors--One size, with % in. connections with or without electrical cut-out switch. Maximum pressure 15 lbs per sq. in. Maximum cold water main pressure, 150 lbs per sq in., mini mum not less than 25 lbs per sq in. Prevents breakage in low pressure heat ing boilers when the water level becomes inadequate. Ask for Bulletin B-727. Other Steam Heating Specialties-- Double Service Valves, Check Valves, Lift Fittings, Gauges, Motorized Valves, Steam and Oil Separators, Sight Glasses, Vacuum Breakers. Ask for Bulletins. RADIATION AND HEATING SURFACE Webster System Convector Radia tion--Non-ferrous convector radiation. Each Webster System Radiator includes a complete enclosure of furniture steel with baked prime coat. Choice of two types of enclosure, fully recessed, with Enclosure available in four types, for mounting along outside wall close to floor or under windows. Delivered as complete "package," it includes all com ponents needed. Can be used as separate convector unit or for wall to wall appli cation. Available without cover for low cost installation. For steam or hot water heating. Radiation may be orificed for steam installations. Ideal for educational or institutional buildings and other.commercial structures. Ask for Bulletin B 1551. 1440 Warren Webster & Company Heating Systems uSt 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. PROPELLER FAN UNIT HEATERS Designed to incorporate four 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 it 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 Healing 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 UNIT HEATERS Sturdy blower-fan units for the economical heating of large areas. Standard (Non-Thermadjust) Type. Used principally where heating is by recirculation only, and where constant heat output is desired during operation. Thermadjust Type. Employs dampers in front of casing and over face of heating element to provide mixing of unheated and heated air, pro ducing heat output in accordance with requirements and con tinuous circulation of air volume. Valve Controlled Type. Unit is of standard casing arrangement but equipped with Nesbitt Heating Surface and Steam-distributing Tubes for automatic control of heat output. Floor mounted, wall mounted, ceiling suspended, from 101,000 Btu/hr, 2450 cfm, to 1,008,000 Btu, 16,350 cfm. Pub. W-N 128. . Fig. S Blower-Fan Type Fig. S Doum-Blow Type LITTLE GIANT UNIT HEATERS Adaptable to a wide variety of applications and field condi tions. Seven 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 four larger models are of the draw-through type; produce the high discharge velocities necessary to blow long distances. These four 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 348,000 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. 1441 1 ' Heating Systems specialities Yarnall-Waring Company Manufacturers of Steam Specialties 133 Mermaid Ave.; Philadelphia 18, Pa. " YARWAY IMPULSE 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 beat-treated; bonnet is cold rolled steel, cadmium plated; cap is tobin bronze. For 600 lb, 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--J in. trap weighs only li lb. 2 in. weighs 8| lb. Small Size--I 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 seat. 750,000 sold. Stocked by 200 distributors. Send for descriptive Bulletin T-1740. YARWAY FINE-SCREEN STRAINERS Offer better protection against rust, scale and dirt for all steam equipment. Ten standard sizes 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 S-203. List Prices, Weights and Dimensions I?o. GO Serie^-to 400 lb; 120 Series--to GOO lb - Size w Ye' 19 1H' 1H' V Complete Trap Series 60 Complete Trap Series 120 Weight Pounds $15 22 < 25 37 m 2 31 52 2M 48 80 4 68 114 554 00 150 854 Length Inches 2M 3 3M 354 454 454 YARWAY EXPANSION JOINTS 3 Heating Systems vanes, au The Dole Valve Company Mam Offices and Factory: 1933 Carroll Avenue, Chicago 12, 111. WATER MIXERS ^ THE ALL STAR LINE THERMOSTATIC AIR CONTROL <cAIR AND VACUUM ^ v=1, VALVES "DOLE THERMOSTATIC AIR CONTROL" 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 Air Controls are avail able in two sizes and will fit 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. DOLE AIR AND VACUUM VALVES Dole No. to _ Fidly 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. I DOLE WATER MIXERS ! Dole Water Mixers provide safer, tem pered domestic hot water on all tankless heater and storage tank installations. Available in 3 sizes, M in., % in., and ! in. 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 Gland- akt types: Gun-pakt (illustrated) has xed 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 ptilities and industrial firms. Send for. Bulle tin EJ-1912. . 1442 1443 Heating Systems values The Fairbanks Company 393 Lafayette Street- New York 3, N. Y. Boston; Pittsburgh; Binghamton, N: 7.; Rome, 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 ~ 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 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. , IRON BODY GLOBE & ANGLE VALVES Bronze Mounted Pressures--125 through 250 Lbs S.W.P. Ends--Screwed and Flanged Discs--Bronze, Renewable Composition, Nickel Semi-Plug Disc and Seat Bonnets--O. S. & Y. ' Automatic Stop and Check Valves Alloy 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 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 1444 Heating Systems Valves and Fittings Hammond Brass Works 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 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. 301--Balancing Elbow-Male Union 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. 305--Balancing Fitting-Male Union and Female Thread. For concealed or convector type radiators. Hammond Radiator Valves and Elbows for Steam and Gravity Hot Water Heating Systems 6 No. 100--Steam Angle. Can also be used for vapor. 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 ing 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 for 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. See Hammond Catalog for complete line of valves. . Warehouse stocks located in 29 cities throughout the United States for your conveni ence and prompt delivery, at our regular prices and terms. 1445 I ' Heating Systems Vaivea Homestead Valve Manufacturing Co. P.O. Box 127 'Serring Since 1892" --. _ Coraopolis, Pa. Makers of Radiant Heating Valves and All Kinds of Plug Valves HOMESTEAD-RADIANTROL VALVE The Combination Balancing Valve ' and Air Vent for Radiant Heating Systems Provides control of room temperatures to meet varying requirements. . Is designed for simplicity and conveni ence of adjustment; and Engineered for ease and low cost of in stallation. Homestead Radiantrol Valves are but terfly type valves, which permit slight passage of water in the "closed" position. A quick quarter-turn fully opens or closes the valve. Graduations between "open" and "closed" positions give instant choice of amount of hot water for each panel. In "open" position valve provides nearly full pipe area flow. In the simplest sense, the Homestead Radiantrol Valve performs the same function for each radiant heating panel as the manual valve on a radiator, or the shutter on a hot air grille. It controls the flow of'hot water to each panel-or room in accordance with the varying heat requirements caused by differences in types of floor covering, changes in wall or ceiling construction, addition or elim ination of storm sash, individual likes and dislikes, etc. The Homestead Radiantrol Valve is an unique combination balancing valve and air vent for radiant heating systems. Saves up to $25 per panel in installation costs through: 1. Eliminating cost of making spe-' cial valve "wells" and covers. 2. Eliminating need for separate riser air vents. Chamber in neck of valve body is espe cially' designed to collect trapped air without restricting flow. Vent screw on valve cap provides simple means of removing trapped air from system. The Radiantrol Balancing . Valve is a "must" for any radiant heating system of more than one panel in order-- 1.'to insure proper flow needed to offset the various heat losses en countered; and 2. to remove air from each heating panel. Valve bodies are made of wrought iron, steel, or brass pipe with beveled or sweat ends for welding or soldering. Valve floor plates may be had with locks to prevent tampering; or with positive adjustable stops to limit opening and save rebalancing system. Radiantrol Valves are available in either foot-control or hand-wheel types; sizes i in., i in., 1 in. and 11 in. Controls heat in each panel; and balances Write for, complete catalog, Reference heat between various panels. - Book 39-7. No obligation. 1446 Heating Systems vim Jenkins Bros. 100 Park Avenue, New York 17, N. Y. Bbidoepobt, Conn.; Boston, Philadelphia, Chicago, San Fhancibco, 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 Horizontal Check Valves.--bronze, iron and steel; Hose Valves; Indicator Rosts; Lock Shield Valves. requirements. Below is a brief list. Needle Valves; Non-Return Valves; All-Iron Valves,--globe, angle, gate; Quick-Opening; Self-Closing Valves. Angle Valves,--bronze, steel, and iron body with bronze mounting or trimming. Radiator Valves; Rapid Action Valves; Regrinding Valves; bronze and iron body Blow-Off or Y Valves,--bronze and iron. Electrically Operated Valves, Gates, with bronze trimming; renewable plug seats and bevel seats of a special nickel alloy in globe, angle, check and swing check patterns. 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. 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. " 1447 / -V Insulation Air Ducts The Philip Carey Mfg. Company Lockland, Cincinnati 15, Ohio PRODUCTS District Offices In AH Principal. Cities CAREYDUCT is recommended whereever 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 com mercial 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. GOOD LOOKING. Surfaces are smooth and free from unsightly raised seams or joints. No stiffeners or braces. Blends well with modern interiors. . INSULATED. High-efficiency insula 5 TYPES OF CAREYDUCT tion assures delivery of hot or cold condi Insulated and Acoustical (I. & A.) Type. tioned air to outlets with minimum Built of asbestos sheets with an inner change in temperature. core and an outer jacket. Combines duct, insulation and acoustical treatment into AIRTIGHT. Won't "breathe" or vi one unit. brate at high velocities. Slipjoint con struction prevents leakage. Single Wall (S.W.) Type. This is an all asbestos duct designed for ventilating SAVES SPACE. Being 40 per cent to 50 per cent quieter than ordinary duct, Careyduct handles higher velocities, per and heating where a high degree of in sulation is not essential. It is ideal for residential heating. mitting the use of smaller sized ducts. Asbestos - Cement (K.D.C.A.) Type. Made of asbestos-cement wallboard in EASY TO INSTALL. Prefabricated different thicknesses. Shipped knocked Careyduct units are easy to install-- down ready for assembly. particularly in tight places. Simple low cost fittings can be made in the shop or on the job. Firefoil Panel (K.D.F.) Type. Fabri cated from Firefoil and shipped knocked down ready for assembly. For high tem FIREPROOF. Being 100 per cent as perature work. bestos construction Careyduct won't smoulder or burn. Approved by Under writers' Laboratories, Inc. Acid and Fume (A. & F.) Type. Built of asbestos sheets laminated together and treated with two coats of acid, alkali and water resistant coating. Ideal forlabora- * Installation tinder jurisdiction of International Sheet Metal Workers, A. F. of L. ' tones or industrial work. 1448 Insulation Air Ducts Pipe The Philip Carey Mfg. Company Lockland, Cincinnati 15, Ohio District Offices In AQ Principal Cities PRODUCTS CAREYCEL FOR AIR DUCTS Uses: A fireproof, low cost, high ef ficiency asbestos board for insulating ducts and all types of air conditioning equipment. Use 1 inch thickness up to 85F 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 11 lb per board foot. Sheet Size: 36 in. x 36 in., or cut to order.. Blocks: 6 in. x 36 in. Thick ness: i 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 i in.; 1 in'., double \ in. and double 1 in. thick sections, finished with cotton duck jackets and bands. CAREY PROTECTO TO CAREYCEL PREVENT FREEZING FOR HEATING SYSTEMS Uses: Designed especially to reduce Uses: Pipe coverings and blocks for the danger of freezing of exposed water pipes, boilers, ovens and other apparatus pipes. where the temperature doesn't exceed Description: Consists of two inner 300 F. Use 1 inch thickness for tem layers of hair felt, a waterproof felt liner peratures up to 300 F. and an outer layer of insulating felt Description: Pipe covering sections (wool felt). For severe conditions--ex 36 in. long by 1 in. thick, finished with posure down to 0 F--use two-inch thick cotton duck jacket and bands. Blocks: ness. 36 in. long sections with cotton 6 in. x 36 in. Sheets: 36 in. x 36 in., or duck jacket and bands. Standard thick cut to order. Thickness: 1 in. up. ness--approximately 1} in. 1449 Insulation 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 on duct runs is required). i . Shipped in compressed rolls. (See Sweet's File (Arch.) or write for A IA File 37-D-2) Thermal Efficiency of Ultralite Duct Insulation is shown in table at right. Tests were conducted by independent laboratories with A STM approved, guarded hot plate methods. THERMAL EFFICIENCY DENSITY "K" VALUE AT 60" 941J"ff / cu ft "" 1M" "" .253 .246 .235 2" "" .233 3" "" .217 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'tbreak, chip or dent. Available in K 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 A/A File 37-D-2) Density lbs/cu It 3 Thickness i" 1" ACOUSTICAL TABLE Sound absorption Coefficients at Frequencies 123 256 512 1024 2048 .11 .46 .42 .67 .80 .15 .53 .65 .90 .87 4096 .80 .90 NRC .60 .75 1450 Insulation Duct Owens-Coming Fiberglas Corporation General Offices--Toledo 1, Ohio. Pacific Coast Division; Box 89, Santa Clara, California. Fiberglas DUCT INSULATION For highly efficient thermal and acoustical insulation of ducts andduct systems, there are three distinct styles of Fiberglas* Insulations--each designed for specific chMfc insulation application requirements. FIBERGLAS COATED DUCT INSULA TION is versatile, lightweight Fiberglas PF (Preformed) Insulation both surfaces of which have been uniformly coated with a finish which improves handleability. Can be used on interior and ex terior duct surfaces. Standard size 24 by 48 in., in various thicknesses. Thermal conductivity (k) is approximately 0.23 Btu at 75 F mean temperature; the in sulation is recommended for tempera tures up to 450 F. CUT WITH A KNIFE--Fiberglas Coated Duct Insulation may be cut accurately with a knife to conform to irregular shapes and curved surfaces, is easily installed and provides a neat and lasting insulation for hot or cold ducts. FIBERGLAS PF INSULATION--PF In sulation is recommended for even greater economies on concealed duct work. It is also used for ducts which require a canvas or plaster finish. Available in densities from 2i to 10) lb per cu ft, PF Insu lation is useful to 600 F and has physical characteristics comparable to Fiberglas Coated Duct Insulation. (Fiberglas PF Insulation is not suitable for application to duct interiors.) FIBERGLAS AEROCOR* FLEXIBLE DUCT INSULATION--Aerocor is made of superfine glass fibers nearly thirty times as fine as human hair, lightly bonded into a fluffy blanket form. It is exceptionally efficient and useful up to 600 F. Aerocor is especially adaptable for inexpensive applications on the ex terior of concealed ducts and for all ducts of a circular or elliptical section. It pro vides savings in material and application costs. . Ajfo WHERE TO BUY FIBERGLAS INSULA TIONS--Check yellow pages of your phone book for name of your local Fiber glas applicator. If not listed, write Dept. 44, Owens-Corning FiberglasTCorporation, Toledo 1, Ohio. TnliifWVr <'Re1' U/tS' and AEROCOR are trade-marks oj Owens-Coming Fiberglas Corporation Toledo, Onto, Sot a vanetp of product* made oj or totlh fibers of glass. forponuson, 1451 Insulation au- Ducts Grant Wilson, Inc. 141 West Jackson Blvd. ASBESTOS DUX-SULflTIOnChicago 4, Illinois PROTECTED Specifications THERMAL: All sheet metal duct work from the unit (heating or cooling) shall be insulated oh the outer surface with Asbestos - Protected Dux - Sulation as manufactured by Grant Wilson Inc. to the thickness specified (or indicated) on the drawings, applied in accordance with the manufacturer's directions. Grant Wilson Dux-Sul Glue shall be used for applying Dux-Sulation and Dux-SulTape shall be used for sealing the joints and corners. ACOUSTICAL: All sheet metal duct work from the unit (heating or cooling) to the registers or grilles shall be lined _ on all four (4) inner surfaces with l/i in.' thick (or thickness shown on drawings) Asbestos - Protected Dux - Sulation as manufactured by Grant Wilson Inc. Ap plication shall be in accordance with the manufacturer's directions. Acoustical Values 70 Per Ceut Reduction in Loudness Fbbqdenct Feet 1035.................................................................................. 9.6 '2048............................................ 9.7 4100................................................................................... 11.4 517.................................................................................... 15.2 259.................................................................................... 31.0 129 ................................................................................... 34.0 Samples and Literature on Request THERMAL INSULATION: Dux-Sulalion saves 75 per cent of heat otherwise lost through ducts. It has a K factor of 0.27 Btu and is composed of flexible fibres fabricated into a strong felt with millions - of dead air spaces. A heavy Asbestos membrane, woven just below the outer surface, adds fireproofing qualities. Dux-Sulation comes in in. and 1 in. thicknesses (100 sq ft rolls), complete with adhesive and Asbestos strips for sealing joints and corners. ACOUSTICAL INSULATION: Dux-Su lation, when applied to the inside of Air. Conditioning and Ventilating Ducts, re duces noise travel 70 per cent in less than 10 lineal feet. It has a low frictional resistance coefficient of F = 0.0001322. Surface Temperature of In- DUX- Temperature 40F 60*F 80-F 100*F 120F 150*F Room Temperature--Deg F 30 60 70 90 33 48 63 78 37 63 68 83 42 57 72 88 47 62 77 93 52 68 83 97 60 75 90 105 Relative Humidity 20% 40% 60% 80% Room Temperature--Deg F (Dry Bulb) 30 50 70 90 0 12 28 44 10 27 45 64__ _ 18 37 56 75 25 44 64 84 Note: As uetenmaea uirougn uam* Tables above, the Surface Temperature of the DuxSulation must be HIGHER than the DEW POINT to prevent condensation. 1452 Insulation conduit Durant Insulated Pipe Company 1015 Runnymede Street, P. O. Box 88 Palo Alto, California TRADE-MARK REG. U. S. PAT. Eastern Manufacturing and Sales Associate DURANT INTERNATIONAL CORPORATION Williamstown, New Jersey REPRESENTATIVES IN PRINCIPAL CITIES I-. OFF. DURANT Pre-Sealed INSULATED PIPE Provides Positive Protection for Underground or Overhead Conveyance of Steam, Hot Water or Refrigerants Construction and Piping Details of D. 1. P. The patented construction principle used in the manufacture of DIP has provided effective, reliable and enduring insulation for the conveyance of hot or cold liquids and gases on many types of installations during the past twenty-five years. While each installation is custom designed to meet specific conditions and require ments, DURANT catalogs a wide variety of factory-built fittings--such as, ells, tees, expansion loops and bends--ready for easy installation in the field. DIP Research has recently developed a new insulating anchor which isolates the pipe electrically from the anchor plate, eliminating potential corrosion by elec trolysis. The DIP Engineering Staff is always ready to confer on your piping problems, and to supply detailed information or construction data. DURANT Processes and Products are protected by Registered U. S. Patents and Patents Pending . 1453 Insulation Conduit and Underground fThsrm-O-Tilt^ H. W. Porter & Co., Inc. ' 817-G Frelinghuysen Ave., Newark S, New Jersey Permanent Protection and REID HAY-DEN, INC. PInispuelaLtinioens.for Undergroun-d Baltimore, Md. Richmond, Va. Charlotte, N.C. Also sold and installed by Johns-Manville Construction Units in all principal cities. The Outstanding Advantages of Therm-O- Tile are: 1--PERMANENTLY higher efficiency. A permanently DRY conduit. DRY insulation. 2--PERMANENCY means: "much longer life." 3--Positive sealing throughout. Posi tive internal drainage. 4--Arched construction. Stronger than required by ASTM. 5--"Spread - footing" foundation. The "sidewalk" makes installation easier. 6--Surrounded by sealed air. 7--All loads transmitted directly to an unyielding base. 8--Correct slope is PERMANENT, hence no condensation pockets. 9--PERMANENCE assures lowest ulti mate cost. Maximum economy. With wet insulation, efficiency drops drastically, and unless the conduit is built on an unyielding foundation there may be sagging and collection of water in pockets. Always Drained. The Therm-O-Tile concrete base contains a drainage chan nel--see photograph--which carries off all water that may enter the conduit from any source, thereby keeping the insulation PERMANENTLY dry.' Drainage is entirely internal and ample to keep the pipe space always dry. Open to thorough inspection at any time at manholes. "Spread - Footing" Foundation. The Therm-O-Tile foundation base is a thick concrete slab poured directly in the trench bottom. Settling and sagging are thus positively prevented. The original THERM-O-TILE STEAM PATENTED CONDUIT SYSTEMS Thie assembly view shows "nearly everything." Note channel drain in concrete base which makes for "permanent pro tection" of the insulation and assures continuous high efficiency. PERMANENT Therm-O-Tile has long been well known to all leading heating and ventilating engineers, but we wish, again, to emphasize the importance of correct slope is PERMANENTLY held so that condensate pockets cannot form. Steel reinforced or placed on piles when installed over filled or boggy ground to "Permanent protection." ' It is not diffi insure PERMANENCY. cult to provide TEMPORARY pro tection and insulation under ground. Threads and joints don't fail immedi ately. Foundations don't sag immedi ately. But unless the job is properly Numerous Conduit Sections. Base and top sections of the Therm-O-Tile enve lope are made in a number of different sizes. These make 27 conduit sections available. For complete information done INITIALLY it won't be long before ask for Therm-O-Tile Bulletin. water seeps in and ruins the insulation. Cost is Competitive. Despite the su perior features that are obtained in Therm-O-Tile, it is nevertheless competi tive in total first cost. Manufacturers Engineers - Contrac tors. Write or call the nearest Porter- Hayden or Johns-Manville Technical Service Unit for recommendations, esti mates of cost, and complete specifications Showing the Use of Filler Type Insulation. Showing the Use of Sectional Pipe Covering. for the conduit and insulation on any underground pipe line project. _ 1454 Insulation Conduit and Underground The Ric-wiL Company PREFABRICATED INSULATED PIPING SYSTEMS UNDERGROUND OR OVERHEAD Union Commerce Bldg., Cleveland, Ohio Agents in Principal Cities Ric-wiL produces complete insulated piping systems designed and engineered to specific operating requirements for transmission (with the lowest possible ther mal loss) of steam, hot or refrigerated liquids or gases. Prefabricated units with single or any. HEL-COR Imulatd specified combination of pipes, in com ., plete sealed 21-ft sections. Helical corru- 'i?j j gated conduit, asphalt and phenolic- r resin coated, wrapped with asphalt n saturated asbestos felt. . Cast-Iron Injn- laid Pipe t/nin Heavy, corrosion-resistant cast iron is used as the protective housing for this pre-assembled underground system. Std. units are 18 ft, 6 in. Tong, with all acces sories furnished. Units are connected with standard mechanical joint, solid ' sleeves, or flanges. Pipe and insulation are housed within HEL-COR insulated a 16-g_age spirally corrugated ingot iron Pi Unit--M conduit, hot-dip zinc galvanized and .If*, j..__ coated on the inside with a corrosiona resistant phenolic resin. Available in single or multiple pipe systems, pre' fabricated in 21-ft lengths with all joint materials and accessories. * Standard TUe Conduit (Sectional) Super-Tile Conduit {Sectional) Vitrified and glazed A.S.T.M. Stand ard Tile housing--acid and weather proof. Foundation type drain supporting pipe with correctly engineered pipe sup port. For single or multiple pipe system-- sectional pipe covering or filler type insulation. 2 ft standard lengths. Similar to Standard Tile but with double-strength walls for heavy over head loads. Will support static load of 6 tons per wheel under actual installed conditions. Heavy duty tile base drain. Cast-Iron Conduit {Sectional) Heavy duty reinforced cast iron con duit for use m shallow underground in stallation close to or under rail traffic. Durable watertight vibration proof clamps insure tightness. 4 ft lengths. mo r< i. ' r?e *ma For use where installation conditions require concrete pads. Side walls are double-cell vitrified trapezoidal design. Arch may be Standard Tile, Super Tile or Cast Iron. For full technical information on Ric-wiL products and services, call or write the Ric-wiL office nearest you or Dept. 16-Z in Cleveland, Ohio. 1455 Insulation Pipe Covering Union Asbestos & Rubber Company 332 South Michigan Ave., Chicago 4,Ulinois UNARCO AMOCEL AND UNIBESTOS INSULATIONS For Temperatures up to 1200 F. For convenience, high thermal efficiency, and the economies of single-layer appli cation, always specify "Unarco." Three great insulations to serve you, all made from Amosite--the strong, light, longfibre asbestos that withstands moisture, heat, acid fumes; has high structural strength and impact resistance. For temperatures to 750 F, Use Unarco UNIBESTOS NO. 750 For temperatures to 1200 F, Use Unarco UNIBESTOS NO. 1200 ' Both types of Unibestos are regularly furnished in 3-foot lengths as cylinders or half-rounds in popular thicknesses to 4 in. for pipe from J in. to 24 in. Greater thicknesses and larger sizes available to 44 in. O.D. Unibestos 1200 is also made in blocks 36 in. long; widths to 36 in. in 6 in. increments; thickness to 3 in. For temperatures to 600 F, Use Unarco AMOCEL, made for pipes from J in. to 12 in. Furnished in 3-ft half-rounds with jackets and bands. Unibestos and Amocel are easy to cut and to fit; may be removed and reapplied re peatedly without loss of thermal effici ency. Carried in stock in principal in dustrial centers from coast to coast. Write for quotations and literature. A COMPLETE INSULATION SERVICE Unarco insulations also include hightemperature cements; tailored-to-fit in sulations of asbestos, glass fibres, glass cloth; and flexible insulations which wrap-on, lace-on, slip-on--all made at Unarco plants in Illinois, New Jersey, North Carolina, and Texas. Technical data and recommendations on request. 1456 | Insulation Packing Union Asbestos & Rubber Company 332 South Michigan Avenue Chicago 4, Illinois PACKINGS, GASKETS, AND TEXTILES Unarco Asbestos Packings, Gaskets, and Textiles comprise a wide variety of types, forms, and sizes for precise, economical selection for any job. UNARCO ASBESTOS G High-pressure Manhole and Handhole Gaskets: cut and folded from closely woven wire-inserted asbestos yarns Treated for heat-resistance. Regular shapes. Oval or round. J in. through i in. Asbestos-Lead Tubular Gasketing: asbestos-metallic cloth around a hollow lead tube. Optional dimensions. Ver HIGH-PRESSURE PACKINGS. Spi ral, coil, or ring-form. Plain or semi- metallic asbestos. With or without a core of red rubber. 1 in. through \ in., in increments of in. Good for 500 F; pressure to 300 psi. BRAIDED PACKING. Plain or wire- inserted asbestos yarns. Plaited, or . braid-over-braid. Unimpregnated, or with lubricant or coating for use with air, hot or cold water, oil, weak acids, steam. 1 in. through 2 in. square, in increments of A >n. TWISTED AND BRAIDED PACKING. For valve stems: long-fibre or wire-in serted asbestos yarns individually lubri cated or graphited. Twisted, A in. through i in. Round braid-over-braid, | in. through 1 in. For gasoline: as above, but specially treated, and also made in square i in. through 1 in. TWISTED ASBESTOS ROPE. High- grade asbestos rovings. 1 in. through 2 in. SHEET PACKINGS. Compressed, graphited, asbestos fibre sheets for high pressures and temperatures. 50 in. x 50 in. Thickness, A- in. through' i in. Also, cloth woven from asbestos-metallic yams, coated. 40 in. wide. Thickness, A in. through j- in. 3KETS AND TEXTILES satile Asbestos-Metallic Gasketing Tape: widths, i in. through 3 in.; thickness, J in.through jin. Unarco Textile Products include: fibre; yarn; cord; tape, plain or brass-wire-in serted; tubing; and woven cloth--for a multitude of uses. Write for nearest distributor's name or literature. ' 1457- I I ^ Insulation 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 improved ZCRETE system of underground insula tion is a field fabrication adaptable to any size, number or arrangement of pipes. Six inches of insulation is ordi narily used on the outside of all pipes. A minimum of four inches is economical spacing between 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 conven tional systems. The curing membrane provides external water protection and imparts a tensile strength to the conduit. S ^ s--*- i"earn MEMBRANE ,o, TCRETE SUPPORT -- Btocx :- \i :- -vi fiV-hi'v:* -MI Single Pipe Conduit -- B"rCRETE *- MEMBRANE :rO:;Q_ *TCRETE SUPPORT ---- BLOCK . 1 . ' . 1 .. -BAE Two Pipe Conduit . vQ :. i It:',- Multiple Pipe Conduit TYPICAL Z-CRETE CONDUITS Commonly used installations 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. Most open boxes or voids may be filled with Z-CRETE insulation without using rollers, rods, etc. The mass of water re sistant Z-CRETE restricts the move ment of moisture, so special" drainage provisions are not. ordinarily required. Z-CRETE is sold and installed by licensed applicators of Zonolite Company under U. S. Patent No. 2355966--Cana dian Patent No. 439356. There is an ap plicator near you. For further data or information, write Dept. HVG-2. *Z-Crete is a registered trade mark ot Zonolite Company. 1458 Insulation Roof Cooling April Showers Company, Inc. 4126 Eighth Street, N.W. Washington 11, D. C foirflfc f> rwzai ^ )AA R A T E N T E D AUTOM ATI C R F= CO O l_ IN <3 _ (Trade Mark Reg. U. S. Pat. Off.) 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 7,850,000 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 con ditioned), Augusta, Ga., Aerojet Engi neering Corp., Azuza, Cal., Westinghouse Electric Co., Hyde Park, Mass., General Electric Corp., Providence, R. I., Bulova Watch Co., Providence, R. I. Recent installations include:--Westinghouse Electric Corp., Baltimore, Md., 33,480 sq ft, Eastman Kodak Company, Rochester, N. Y., 156,000 sq ft, The Jacobs Mfg. Co., West Hartford, Conn., 85,760 sq ft, Weldon, Williams Lick, Ft. Smith, Ark., 38,000 sq ft, Lily Tulip Cup Corp., Springfield, Mo., 270,000 sq ft, Dixie Cup Company, Easton, Pa., 25,800 sq ft, City of L. A., Pierce Agri cultural College, Cal., 20,000 sq ft, Val-O-Will Farms, Lake Geneva, Wis., 55,000 sq ft. In addition, the Federal Government has over one million square feet of April Showers installations. Among them is the 500,000 sq ft roof the U. S. Naval Ordnance building in Indian apolis, Ind. APRIL S! lOWERSklso'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 system 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 cooling is protected by U.S. Patents. Write for Descriptive Literature No obligation for Estimates A FEW CHOICE DEALERSHIPS STILL AVAILABLE . . . WHITE 1459 f Insulation G1*ss Blocks American Structural Products Company Toledo 1, Ohio--Subsidiary of Owens-Illinois Glass Company INSULUX IHSUUIX CD MASS CLASS BLOCK BLOCK Insulux Glass Block Give Better Control of Interior Conditions What they are--Insulux Glass Blocks* are hollow, hermetically sealed units containing a partial vacuum. Properly used they aia control of interior condi tions to a point where initial and operat ing costs of heating or cooling equipment are reduced. . Conductivity Coefficient of Heat Transmission--The "U" factors for panels of Insulux Glass Block are as follows: Nominal Block Sue *' U** 6' sq. 8* sql 0.60 0.66 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. 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 steel sash as through glass block panels. However, as with sash, glass block transmit less solar heat when properly oriented and shaded. Complete in stantaneous solar heat gain data for all block designs and for all exposures are given on pages 294 and 295 of this "GUIDE." , Design, Sizes, Erection Insulux 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 3f in. Complete technical data, description, and details will be' gladly sent. Just address American Structural Products Company, Box 1035, Toledo 1, Ohio. Surface Condensation Because of the low over-all, air-to-air heat transfer, the exterior air tempera ture which will produce condensation on a glass block panel is much lower than that for ordinary windows. This per mits higher humidities where needed, for air conditioning for both comfort and industrial processes. Being glass, they cannot rust, rot, nor corrode . . . are not subject to deterioration caused by mois ture. Infiltration A panel of Insulux Glass Block provides a wall of glass and mortar which seals Photographs and illustrations above show koto Insulux Glass Block effectively controls daylight. To the left you see what happens when light beams strike an the building against infiltration. . Dust, drafts and air and vapor leakage are minimized. Natural ventilation re ordinary window. Notice uncomfortable, harsh bright ness near windows, extreme contrast in other parts of room. To the right, notice how the built-in prisms in Insulux Glass Block No. S6S throw light UP, and quirements can be met by installing spread it. Result is even, diffused light over all parts Reg. U. a Pat Oft. of the room. 1460 Insulation GUss Blocks Skylights American 3 Way-Luxfer Prism Co. 431 S. Dearborn St. Chicago 5, 111. 270 Park Ave., New York 17, N. Y. Products: American 3-Way Rooflights made of glass blocks of special strength and design in 3 arrangements for adaptation to all types of skylights in commercial, industrial, and institutional buildings. American Skylights and Skylight Ventila tors for special applications. American Magnalite Diffusing Glass Blocks for sky lights, and for doors, ceiling lights, screens and partitions. Benefits: American 3-Way Rooflights make possible many benefits, including maximum diffusion of soft light over greater area, increased structural at tractiveness, easy cleaning, long life, dust and air resistances, lower heat transfer, and reduction of solar heat transmission. Construction: American 3-Way Roof lights use specially designed, semi-vac uum glass blocks approximately 9 in. sq, 2 in. thick, set in a 3} in. thick, reinforced concrete grid. Each glass block is made of water-white crystal glass, designed solely for skylight use. American Glass Block Skylight Elements incorporated assure maximum light diffusion. Each glass block is sealed in place with permanent Tees-Ess compound applied in fluid form at about 280 F, insuring homogeneous, weatherproof seal. Non-ferrous metal reglets set and anchored in the reinforced concrete grids around the outer rows of glass blocks provide arrangement for weather-tight flashing connections with any type of roofing as per standard Hashing detail. IDEAL FOR AIR CONDITIONED BUILDINGS Reduces Seat Transfer: Tests using methods suggested by the A.S.H.V.E. Con ductivity Test Code show that Glass Block Rooflights have about two-and-one-half times the insulating value of sheet metal skylights. Reduces Solar Heat Transmission: Reduction in total solar heat gain as compared with ordinary windows is indicated by relative values given in Tables 23, 24, and 27 in Chapter 12. Reduces Condensation: Due to the nature of the grid construction where insulating materials are employed with semi-vacuum glass blocks assemblies, there is little or no tendency for condensation to form on the underside. Light Up--the AMERICAN way! CXTRUOCO COVTRn.ATE-COffTINUOU3 IN ONC OIRZCTION - - 1461 1 l Insulation GI*ss Blocks Pittsburgh Corning Corporation Room U52, 307 Fourth Avenue, Pittsburgh 22, Pa. PC GLASS BLOCKS Distribution by Pittsburgh Plate Glass Company; W. P. Fuller & Company on the Pacific Coast;. Hobbs Glass Ltd. in Canada; and by leading distributors of building materials everywhere. - ' Also makers of FOAMGLAS. '' THERMAL INSULATION . PC Glass Blocks allow the economical use of large glass lighting areas, reduce heat loss in cold weather and materially aid air-conditioning. This is because each PC Glass Block contains a sealed-in dead- air space that is an effective retardant to heat transfer. Tests by nationally recog nized laboratories have established the value of glass blocks for insulation. See pages 294 and 295 of this Guide. SURFACE CONDENSATION Due to high insulating value, condensa tion will not start forming on the room side of glass block panels until outside- air has reached a temperature much lower than that necessary to produce condensation on single-glazed windows. The accompanying chart shows at what temperatures condensation will form. condensation even at high temperature and humidity levels. SOLAR HEAT GAIN The use of glass blocks for light-trans mitting areas results in a marked reduc tion in total solar heat gain as compared with ordinary windows. This factor is of considerable advantage in buildings that are properly air-conditioned, but does not eliminate the need for adequate ventilation or shading in non-air-condi tioned rooms. For data on solar heat gain through glass blocks see tables 23 and 24 in the solar radiation section of this Guide--chapter 12. The tables are for standard pattern glass blocks. PC GLASS BLOCKS AID AIR-CONDITIONING Two of the chief aims of air-condition ing1--temperature control and cleansing of air--are aided by the use of PC Glass Blocks. Heat loss is less in winter--heat gain is less in summer. Solar heat trans mission and radiation are reduced. Neither dirt nor drafts can filter in, for each panel is a tightly sealed unit. PATTERNS, SIZES, INSTALLATION For example, with inside air at 70 F and relative humidity at 40 per cent condensation will not begin to form on the interior surfaces of a panel of single cavity glass blocks until an outdoor temperature of minus 14 F is reached. Under similar conditions, with single- glazed sash, moisture will begin to form when the outdoor temperature reaches 33 F. PC double cavity blocks (LX patterns)--in which a fibrous glass screen is inserted between the halves of the block--provide even better in sulation value, with less chance for PC Glass Blocks are available in decora tive and functional patterns--the latter designed for special control and direction of transmitted daylight. They are made in three sizes: 5% in. x 5% in., 7% in. x 7% in. and 11% in. x 11% in. (generally referred to as 6 in., 8 in. and 12 in.). All are 3% in. thick. Special shapes are available for turning corners and for building curved panels. Any mason can install PC Glass Blocks; no special tools are required. For complete information, write the Pittsburgh Corning Corpora tion, Pittsburgh 22, Pa. 1462 Insulation oust Pittsburgh Corning Corporation Room T52, 307 Fourth Avenue Pittsburgh 22, Pa. FOAMGLAS--the long life insulation This is foamglas. The entire strong, rigid block is composed of millions of sealed glass bubbles. They form a con tinuous structure which has unusually high resistance to moisture, vapor and acid atmospheres, is incombustible, ver min-proof and odorless. In those closed glass cells, which contain still air, lies the secret of the material's long life insulating efficiency. On new and existing walls, and as free standing partitions, foamglas supports its own weight. It remains in place ., . insures a long lasting barrier to vapor transfer and heat and cold. In foamglas you find a unique combina tion of properties which make it a truly effective and economical insulation-- whether for buildings or for indoor and outdoor pipe lines and equipment. foamglas is a cellular glass material which effectively retards heat travel, wherever it is used. Its exceptionally high resistance to moisture, vapor and many other destructive elements en ables foamglas to retain its original insulating efficiency. Freedom from re pairs, maintenance and replacement keep foamglas insulating costs low. You can get complete, up-to-date in formation on foamglas in our current literature. We shall be glad to mail you free copies of our booklets--and a sample of the material. On roof decks, rigid blocks of foamglas provide a firm level base for roofing felts. The long life insulation value of foamglas can be depended upon to help maintain desired indoor temper atures and humidities. isfoamqlas used to insulate process equipment and pipe, lines. It is avail able in standard flat blocks and curved segments to fit equipment, and in pre formed sections for standard pipe sizes and fittings.* foamglas used under concrete wear ing floors--or around the edge of floors on ground--reduces heat loss, increases comfort. Its high compressive strength supports heavier than normal floor iuaub. When you insulate urith FOAMGLAS, the insulation lasts! 1463 Insulation Armstrong Cork Company Building Materials Division Lancaster Pennsylvania Offices Aidant Allentown Anchorage Atlanta Baltimore Birmingham Boston Buffalo ' Charlotte Chicago Cincinnati Cleveland COLUMBUB Dallas Denver Detroit Evansville Harrisburg Hartford Houston Indianapolis Jacksonville Kansas City Los Angeles Louisville Memphis Milwaukee Distributors Minneapolis . New Orleans New York Omaha Philadelphia Pittsburgh Portland Providence Richmond Rochester St. Louis San Francisco Seattle Spokane Syracuse . Tacoma Tulsa ` Washington, D. C. Wilmington Charleston 23, W. Va.. .Capital City Supply Co. Eau Claire. Wis......................................Horel-George Co. El Paso. Texas. .Case Industrial Service Company Fort Wayne, Ind..........;..........................The Baldus Co. Grand .Rapids, Mich. Tony Batenburg Insulation Co. Green Bay, Wis. ,_ , _ , _ Northwestern Asbestos and Cork Insulation Co. Jamestown, N. Y.... Laco Roofing & Asbestos Co. Joplin, Mo....................................................Joplin Cement Co. Manitowoc, Wis. ( Northwestern Asbestos and Cork Insulation Co. Phoenix, Abiz...............................................Barrett & Holmes San Antonio, Tex. .... General Supply Co., Ino. South Bend 23, Ind...........Midland Engineering Co. Salt Lake City, Utah . Asbestos Engineering & Supply Co. Springfield, Mo.............Southwestern Insulation Co. ' Armstrong's Contract Service . 1 in., in.,-2 in., 3 in., 4 in., and 6 in. Armstrong's Contract Service provides thick. K factor: 0.27. trained engineers, supervisors, and in Armstrong's Cork Covering stallation crews that are thoroughly ex perienced in the application of both high- and low-temperature insulations to ducts, piping, and equipment. Backed by more than 40 years of service in the insulation field, this nation-wide organi zation will see that your job is done right from start to fimsh. 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 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 with 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 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 consequent 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 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 OF to 35F; 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, and pipe covering, high- tional finishes. Conforms to Federal temperature block and pipe covering Specification HH-C-561b. Sizes: 36 in. wool felt, hair felt, etc. All are available long; 12 in., 18 in., 24 in., and 36 in. wide; in standard sizes and thicknesses. For detailed technical information, Bampies, and descriptive literature, ask any office or distributor, Specifications appear in Sweet's C italogs for Architects and Engineers. 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 & block form. Complete Insulation Services for High and Low Temperature. Atlanta, Ga. Baltimore 30, Md. Boston (No. Cambridge) 40 Charlotte, 6, N.C. Chicago III. Cincinnati 2, Ohio Mundet Branches Dallas 10, Tex. Detroit 21, Mich. Houston 1, Tex. Indianapolis 4, Ind. Jacksonville 6, Fla. Kansas City 7, Mo. Knoxville 18, Tenn. Los Angeles (Maywood) New Orleans 16, La. New York 17, N.Y. Philadelphia 39, Pa. . St. Louis 9. Mo. . San Francisco 7, Calif. Washington, D.C. ARIZONA Phoenix, Tucson COLORADO Denver CONNECTICUT Hartford D. C. Washington IOWA Amana MINNESOTA MARYLAND M_in__n__e_a_p__o_l__is_ Baltimore MONTANA Anaconda TEXAS El Paso OHIO Toledo UTAH Salt Lake Crrr OKLAHOMA Oklahoma City VIRGINIA Norfolk, Richmond OREGON Portland WASHINGTON Seattle, RHODE ISLAND Providence ' Tacoma SOUTH DAKOTA Brookings W. VIRGINIA Charleston TENNESSEE Johnson City WISCONSIN . Appleton Knoxville, Memphis, Nashville NEW YORK, Avbrill Park, Buffalo, Plattsburg, Rochester, Utica, Westbuby, L. I. 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 in. to % in. granules and compressed under heat in moulds to produce Mundet flat 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. SGovernment 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, lA, in., 1 in., l`/2 in., 2 in., 3 in., 4 in., 6 in. Mundet "Jointite" 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 85per cent magnesia insulation makes available the most modern 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 Section of Mundet Moulded Cork Pipe Covering with PUiing. The pipe covering it made in lections 36 in. long, to fit all licet of pipe. Covers the complete installation of our products, in accordance with best estab lished practice. Divided responsibility is avoided. Materials and workmanship are guaranteed. Send for catalog. 1465 Insulation The Celotex Corporation General Offices 120 South LaSalle Street, Chicago 3, HI. C^ejloteX REG. U. i RAT. OFF. Celotex Insulation Board Products are made by felting long, tough cane fibres 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 % in. or in. with square edges. . 2 ft x 8 ft x % in. with V-type tongue and groove on long edges. Celotex 4 ft wide 26/32 in. Sheathing, 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). Celotex Insulating Lath--Insulation and continuous plaster base in one material. All edges beveled for additional plaster reinforcement at joints. Long edges -shiplapped. Sizes: Regular or VaporSeal, 18 in. x 48 in. x $ in. Celotex Roof Insulation Regular--Natural cane fibre 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., 1$ 2 in. # Preseal--Coated with special asphalt on all surfaces and edges for additional moisture protection. Sizes: 23 in. x 47 in., 24 in. x 48 in. Thicknesses: in., 1 in., H 2 in. . Preseal "SO"--Extra high quality board with conductance "C" before asphalt coating of 0.30 Btu per inch nomidal thickness. Same moisture-resistant as phalt coating as Preseal. Size: 24 in. x 48 in. Thicknesses: 1 in., H 2 in. Vapor-Seal--Has \ in. x $ in. offsets on all edges which form network of channels next to deck, serving to equalize air pressure therein. Asphalt-coated on all surfaces and ed^es. Thermal conduct ance, before coating, is 0.30 Btu per inch nominal thickness. Size: 24 in. x 48 in. Thicknesses; 1 in., 1 in., 2 in. Flexcell* Expansion Joint Filler--Cane . fibre felted into strong, resilient boards, then saturated with durable asphaltic compound. For expansion joint uses, perimeter insulation for concrete floors at grade, sill sealer, 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 walls, roof decks and partitions. Consists of cane fibre board core surfaced on both sides with layer of asbestos-cement board. Sizes: 4 ft wide x 4 ft to 12 ft lengths. Special sizes available. Thick nesses: 11/16 in., 1J in., 1& in., 2 in. Celo-Block*--Cold storage insulation made by laminating in. low density cane fibre boards with waterproof mastic ' and surfacing front and back with waterproofing asphalt. Sizes: 12 in. x 36 in., 18 in. x36in. Thicknesses: 2 in., 3in. Celotex Rock Wool Products--Regular Blankets, full- or semi-thick, 15 in. x 96 in., 15 in. x 48 in., 15 in. x 24 in. Utility Blanket, 15 in. x 96 in. Reflective Blan kets, standard thickness, 15 in. x 96> in. Also Loose, Granulated and Hand-Pour ing Rock Wool. . Q-T* Ductliner--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. Distributors in principal cities. 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 Off. For detailed information on all Celotex products, see Sweet's Files or write The Celotex Corporation 1466 Insul-Mastic Corporation OF AMERICA 1162 Oliver Building Pittsburgh 22, Pa. Representatives In Principal Cities Insulation ^SUbMAS!^ INSULATION--CONDENSATION PREVENTION VAPORSEALINQ INSULATION--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 all 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, Btands 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 100 sq in., per 24 hr is 0.01 grams. APPLICATION--Insul-Mastic is spray applied under heavy air pressure. Insul- Mastic licensees in principal cities have trained crews to do this work. Coatings are applied at the rate of six to eight gal 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, but may be colored with Insul-Mastic aluminum spray or Insul-Mastic colored vinyls. Slate granules of various colors may be blown into the coating while it is wet. LIFE--Accelerated weather- tests identi cal to that of the Bureau of Standards place Insul-Mastic's life at over 50 years in outside weather. 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 (1D '1 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 chicken wire which is brittle, requires two coats plus asphalt; and to the insula tion adds water which may never be driven off. Insul-Mastic and Glasfab is a flexible j'acketing which can withstand abuse such as ladders, foot traffic or fall ing objects. The Glasfab Membrane is imbedded into a tack coat of InsulMastic and then sprayed with a J-in. coating of the mastic. CORROSION PREVENTION--Installa tions of all types from small pipes to large tanks can be kept from corroding by a coating of Insul-Mastic. In chemically laden air or constantly moist conditions, this protection is particularly necessary; and Insul-Mastic's record in paper pulp mills, oil refineries and other industries where corrosion was a great problem confirms the durability of this coating. 1467 I Insulation INSULITE DIVISION Minnesota General Office: 500 Baker Arcade Bldg. and Ontario Paper Company Minneapolis 2,.Minnesota INSULITE STRUCTURAL INSULATION BOARD For 38 years engineers and architects have specified Insulite materials for struc tural uses, interior finish, and for other thermal insulation and sound control work. Insulite materials have proved their merit through actual performance on the job. STRUCTURAL MATERIALS CONDENSATION CONTROL--To pre vent condensation within walls, author ities recommend "sealing the warm side and venting the cold side" of the wall. 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 side of the wall, vapor-permeable Bild- rite Sheathing allows surplus vapor to escape toward the outside. Bildrite Sheathing*--A tough, durable, insulating sheathing material made from new wood fibers. Waterproofed through out by an integral asphalt treatment. Bildrite (4 ft width) has more than twice the bracing strength of horizontal wood, sheathing. 25/32-in. thick. Sizes: 2 x 8 ft. (V-joint on long edges) ...4x8 ft to 4x12 ft. (square edges). Thermal conductivity: 0.36 Btu per inch thick ness. Sealed Lok-Joint Lath*--An insulat ing plaster base, made from tough North ern wood fibers. Horizontal joints are reinforced by patented metal "Loks." Waterproofed throughout by an integral asphalt treatment. Asphalt vapor-bar rier protects against harmful condensa tion. - Thicknesses: A, %, and 1 in. Size: 18 x 48 in. Also available without vapor seal in A-in. thickness. THE INSULITE "WALL OF PROTECTION" ' Bildrite Sheathing (outside) and Sealed Lok-Joint Lath (inside) form, the ap proved Insulite "Wall of Protection." Transmission coefficient (U) for this construction with wood siding exterior is 0.15 Btu/hr/sq ft/F. This value is typical of the results gained by using Insulite materials in frame construction. For further (U) val ues see Chapter 9, pages 186 and 187. SHINGLE-BACKER Shingle-Backer is a fast applying, in sulating under-course material for dou ble-coursed shingled walls. Shingle- Backer's long 4-ft panels take the place of low-grade, wood under-course shin gles. Designed to make faster, easier shingled walls, without waste. Made from waterproofed, J46-in. insulation board, asphalt-impregnated throughout. No building paper is needed. in. thick, 48 in. long. Two widths: 13H in. for 12-in. shingle exposure; 15M in. fr 14-in. shingle exposure. A paying Bildrite Sheathing 1468 * 'jy Applying Lok-Joint Lath Insulite Insulation ROOF INSULATION Insulite Roof Insulation is fabricated from either Ins-Lite or Graylite insula tion board. The J^-in. thickness has square edges. The 1,1}, and 2-in. thick nesses are multiple layers stapled to gether. Available with either square or offset edges. Size: 23 in. x 47 in. INSULATING WOOL Insulite Insulating Wool is made from famous "Fiberglas," consisting of millions of long glass fibers bonded to gether with a thermo-setting resin. Available in the following forms: roll blankets, batt blankets, utility batts, and pouring wool. INDUSTRIAL INSULATION Lowdensite Industrial Board--A 10 to 14 lb density board with average ten sile strength of 100 lb/sq in., and average conductivity of 0.31 Btu/hr/sq ft/F/ inch thickness. Ins-Lite* Industrial Board--A 14 to 18 lb density board with average tensile strength of 250 lb/sq in., and average conductivity of 0.34 Btu/hr/sq ft/F/ inch thickness. Graylite* Industrial Board--Differs from Lowdensite and Ins-Lite in that it's integrally treated with asphalt, Sizes: 4 x 6 ft to 4 x 12 ft. Thicknesses: and 1 in. Primed Graylite Building Board-- Identical to regular Graylite Building Board, but has a prime coating for easy painting. Sizes: 4 x 6 ft to 4 x 12 ft. Thicknesses: and % in. Lusterlite Interior Board--A smooth, tough-surfaced board, factory-painted in White or Light Ivory colors. Easy to clean or repaint. Sizes: 4 x 6 ft to 4 x 12 ft. Thicknesses: H in. . Durolite Interior Board--Rugged pour able interior board with factory-painted finish. Easily cleaned or repainted. Highly.resistant to scuffing and abrasion. Available in Ivory, Pale Green, and variegated, Woodtone colors. Sizes: 4 x 6 ft to 4"x 12 ft. Thickness: in. Smoothlite Interior Board--A natural- colored, factory-coated board , with glossy finish. 68 per cent light reflec tion. Sizes: 4 x 6 ft to 4 x 12ft. Thick ness: in. Wevelite Interior Board--A practical, low-cost interior board with factory- painted finish in Ivory-White color. Easy to clean and repaint. Sizes: 4x6 ft to 4 x 12 ft. Thickness: % in. Tileboard (Lusterlite)--Same smooth, long-lasting finish as Lusterlite Interior Board. Flanged tongue-and-groove joint permits easy, secure fastening with staples, nails, or an adhesive. Sizes: 12 x 12 in., 16 x 16 in., 16 x 32 in. Thickness: ]4 in. Plank (Durolite lA in. and % in)--Same tough, scuff-resistant surface as Durolite Interior Board. Flanged tongue-and- Applying ehinglee and Shingle-Backer which provides increased strength and moisture-resistance. A 16 to 20 lb density board with average tensile strength of 300 lb/sq in., and average conductivity of 0.36 Btu/hr/sq ft/F/ inch thickness. HARDBOARD PRODUCTS groove joint permits easy, secure fasten ing with staples, nails, or an adhesive. Durolite % in. Plank has greater strength and insulation value--requires no furring strips. Colors: Durolite A in.--Ivory, Pale Green, and variegated Woodtones . . . Durolite % in.--Ivory, Pale Green, and Light Woodtone. Sizes: Durolite lA in.--8, 10, 12, and 16 in. wide; 8, 10, and 12 ft long . . . Durolite Yi in.--16 in. wide and 8 ft long. ' Fiberlite Acoustical Tileboard--A lowcost, highly efficient acoustical tile, factory-painted in White. Extremely Insulite 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 A to in. Sizes from 4 x 3 ft to 4 x 12 ft. Many colors and designs available. INTERIOR FINISHES Graylite Building Board--A rugged, durable board, integrally treated with asphalt for maximum strength and moisture resistance. Thermal conduc tivity is 0.36 Btu per in. thickness. Reg. U. S. Pat. Off. high light-reflection (80 per cent). Beveled edges on all sides. Sizes: 12 x 12 in., 16 x 16 in., and 16 x 32 in. Thick nesses: A and % in. Acoustilite Perforated Tileboard--A rug ged, sound-absorbing tileboard for resi dential and commercial interiors. Each tile unit contains 484 cleanly-drilled holes. Available with either flanged tongue-and-groove joint (for staple or nail application), or beveled butt-edge joint (for adhesive or nail application). A in. thick, 12 x 12 in. square. Factory- painted white finish has high light-re flection. 1469 Insulation JMIMUI Johns-Manville Executive offices: 22 East 40th Street, New York 16, N. Y. Offices in All Large Cities Home Insulation Applying Longfibre Super-Felt baits in new home For Existing Homes and Buildings: J-M Type A "Blown" Rock Wool . J-M Type A Rock Wool is blown pneu matically into the spaces between studs in outer walls and between roof rafters or attic floor joists. Insulation thick ness in walls corresponds to stud depth, approximately 3K in. The uniform fill assures maximum thermal efficiency. This type of insulation is installed only by Approved J-M Franchised Home In sulation Contractors, whose trained crews are equipped with the necessary apparatus. For complete information on J-M "Blown" Rock Wool Home Insulation and its application, write the address above or call your local Johns-Manville office. For New Construction: Super-Felt* Longfibre . Batts and Blankets J-M Superfelt Batts and Blankets are made of the revolutionary Longfibre 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. . FUL-THIK BATTS are fabricated of Longfibre rock wool to full stud thickness which assures maximum comfort and fuel savings. Each batt has a vapor-seal back ing paper with extended taking flanges for over-lapping at the framing members which protects against passage of ab normal humidity. Furnished in sizes 15 x 24, 15 x 48, 19 x 24, 19 x 48, 23 x 24 and 23 x 48 inches. Also furnished Seini-Thik. in the same sizes. THICK BATT BLANKETS are quality home insulation blankets fully enclosed in a permeable Kraft paper wrapping. In this blanket the Longfibre rock wool is firmly felted as in the Ful-Thik Batt, then encased for convenience in han dling. It is also backed with a heavy vapor barrier with reinforced tacking flanges. Furnished in sizes 15 x 48 and 23 x 48 in.___ MEDIUM ROLL BLANKETS are used where insulating requirements are not as exacting and where first-cost economy is a factor. Made of firmly felted 'Longfibre rock wool, these easy-to-install rolls are fully enclosed and have a heavy vapor- seal backing with reinforced tacking flanges. Furnished in sizes 15 x 64,23 x 64, 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., K. 1 and IK 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 Re*. U. 8. Pat. Off. per inch of thickness. 1470 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 temper atures up to 600F. Pipe insulation is fur nished in sectional or segmental form for all standard pipe sizesf,in 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 temperatures 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 K in. through 4 in. thick. Rock Cork* J-M 85% Magnesia Pipe Jnevlaiion 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 K in., K in., 1 in., single layer; 1 in. and 1| in., double layer, for all stan dard pipe sizes.t Temp, limit 225 F. 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 2J in. thick, single layer; over 2} in. thick in double layer, for all standard pipe sizes.f ' Re*. U. & Pat Off. Rock Cork is made of mineral wool and an asphaltic binder molded into sheets and pipe insulation for all low temperature service to minus 300 F. It 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., in l, IK. 2,3, and 4 in. thicknesses. Lagging, for curved surfaces, supplied,18iuculong by IK through 4 in. thick, 6 lm wide, depending on diameter. Pipe covering furnished in Ice Water, Brine, and Heavy Brine thicknesses, for all commercial pipe sizes.f Discs also available to a 36 m. max. diameter. . Zerollte* Zerolite is a resin bonded, mineral wool insulation for temperatures to minus 300 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 6 to 10 per cent lower conductivity. Furnished inisheets 18 im by 36 in. (18 in. by 18 in. available in i in. thickness only), in 1 in. through 4 im thickness. Lagging furnished in same sizes as Rock Cork. " Details^ on Request For further information about J-M In sulations and J-M Application Service^ write Johns-Manville, 22 East 40th Street, New York 16, N. Y. f Also available in sections to fit straight runs of copper pipe or tubing with nominal diameters of M in. and larger. f ! Insulation Kimberly-Clark Corporation Neenah, Wisconsin IflMSUL M. . V CAN.FAI ** New York 17, N. Y., 250 Park Avenue Atlanta 3, Georgia, 22 Marietta St., N. W. Chicago 3, Illinois, 8 S. Michigan Avenue San Francisco 4, Calif., 155 Sansome Street 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 Kimsul 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 1. 2. 3. No. 1. Flexible--fits into corners, tucks behind pipes, electrical wiring and othef "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. 5. 6. 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 ricated construction. ., No. 6. Any Width, Any Length--it's easy to cut exact lengths or narrow widtns. Avoids muss and fuss. Workmen do a fast, neat job--with Kimsul. T. M. Reg. U. S. Pat. Off. 1472 1 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, Becure 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 chem ical 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 materi- . als of which Kimsul is made offer no subsis tence to vermin or insects. Special chem ical treatment resists mold and fungus. Reflective KIMS UL Installed. Edge of fastening flange folded over face of framing completes the vapor seal. "k" Factor--0.27 Btu/sq ft/hr/F. 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 Plaster 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 sive as a sound absorbing element. See - (PERFORATED BOARD, FABRIC coefficients below. OR WIRE SCREEN FACIN6 T.M. Reg. V. S. Pat. Of. CONSTRUCTION DETAILS AND HEAT FLOW (U) FACTORS Heat Flow Kimsul GradeHorizontal_______Heat Flow Up Heat Flow Down Heat Flow Down "U" % "U" % "U" % *U" % UNINSULATED REG. COMMERCIAL THICK " STANDARD THICK " DOUBLE THICK REFLECTIVE MED. THICK " DOUBLE THICK .25 .15 .12 .08 .10 .08 .69 40 .25 52 .17 68 .10 60 .15 68 .10 .48 64 .20 75 .15 85 .09 78 .10 85 .08 .28 58 .16 69 .12 81 .08 79 .09 83 .07 43 57 71 68 75 "k" Factor (KIMSUL plies) 0.27* authority of J. C. Peebles, Armour Institute, 1938 (Does not include value of reflective cover.) 'Factors expressed inBtu/hr/sqft/F: k. per inch of thickness; "U" per assembled section of construction. Calculation .based on FHA Technical Circular No. 7, dated Jan. 1949. % = % of uninsulated heat flow stopped in the insulated construction. For further information write to KIMBERLY-CLARK CORPORATION--NEENAH, WISCONSIN 1473 Lockport Cotton Batting Co. Insulation Lockport, New York ACOUSTICAL INSULATION Atlanta Boston Buffalo Insulation Owens-Illinois Glass Company Kaylo Division Toledo 1, Ohio Chicago Cincinnati Cleveland Sales Offices Detroit Houston Minneapolis New York Oklahoma Cxtt Philadelphia . Pittsburgh St. Louis Washington Heat Insulation DENSITY.............. Approximately 11 lb per cu ft. FLEXURAL STRENGTH.... 50 lb per sq in. COMPRESSIVE STRENGTH (at 5% deformation) Before heating................................... 150 lb per sq in. After heating for 24 hours at 750 F....................................... 144 lb per sq in. afcT000F...................................123 lb per sq in. at 1200*F....................................... 117 lb per sq in. After boiling for 24 hours KAYLO HEAT INSULATION, a hydrous calcium silicate, is effective up to 1200 F. (while wet)......................................... 74 lb per sq in. LOSS IN WEIGHT Comes in four featured types to meet every insulation need: (1) Standard, open, blanket roll, backed by tough, waterproof, asphalt-coated kraft paper to form an effective vapor barrier. (2) Enclosed Blanket. Insulation is com pletely enclosed in envelope made of asphalt-coated paper on one side and a porous or "breather" type paper on other side. (3) Open Aluminum Foil-- providing all the features of open Type 1 lus the extra value of aluminum foil acking. Forms an effective vapor bar rier--stops 90 per cent of radiant heat. (4) Enclosed Aluminum Foil. Superior in insulation plus values and thermal effi Easy to Warehouse and Handle. Offers far more "compressibility." Requires one third the trucking and warehouse space of ordinary insulation. 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: 1, 1J4, 2, 3, 3%. Width--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. It performs efficiently through the hot water and low pressure steam range, also through temperatures in the super heated steam range. Therefore, a single material can be used for high tempera tures which usually require combinations of two different insulating materials. Kaylo Heat Insulation is incombustible and insoluble in water. Its light weight simplifies handling, shipping and applica tion. High strength makes breakage al most negligible. Kaylo Heat Insulation can be cut, scored or sawed with ordi nary tools. The material is non-irritat ing to the skin and non-toxic. After heating for 24 hours * at 750 F................................................ at 1000* F................... at 1200 F....................... . .5.5% 7.9% .....9.8% After boiling for 24 hours (after drying)............0.2% RESISTANCE TO ABRASION (Conventional tumbling test-loss in weight after 10 minutes) Before heating..................................................................2.2% After heating for 24 hours at 750 F........................................... 3.7% at 1000* F...................................................................5.7% at 1200 F........................................... 6.9% DIMENSIONAL STABILITY Linear shrinkage after heating for 24 hours ciency. Provides greater convenience, comfort, economy and performance. Thermal Conductivity--The "k" value for cotton is 0.24 Btu/hr/sq ft/degree F/inch. (See table.) _ Light Weight--Weight of 1 cu ft is % lb. (See table.) Flame-Proofed--Withstands 1800 blow torch heat. Moisture-Resistant--Chemical treat ment, combined with natural protective Type of Insulation Wgt.per Cu Ft 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 layerB of paper...................... Eel grass between layers of paper . .875 10.00 1.50 13.50 3.62 3.40 A* Value 0.24 0.27 0.27 0.27 0.33 0.25 KAYLO PIPE INSULATION is made to Simplified Dimensional Standards of thicknesses and diameters for snug nesting, when necessary. Coverings are sectional for tube and pipe sizes * in, to 12 in.; tri-segmental up to 23 in.; quad-segmental up to 41 in.; K-seg- mental (18 in. wide segments) up to 72 in. in diameter. at 750 F.................................................................... 0.8% at 1000 F...................................................................0.9% at 1200* F...................................................................1.5% Elongation after saturation (max.)......................0.04% MOISTURE ABSORPTION (volume) After 6 hours exposure in atmosphere of 120 F and 90% Relative Humidity.............0.9% CONDUCTIVITY (K) At 100* F mean temperature................................. 0.41 At 500 F mean temperature...............................0.54 coating on cotton fibres, enables -cotton to effectively resist moisture. Prevents rot and mildew. Smooth Texture--Cotton contains none of the sharp particles that irrithte the skin. 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...................... 1.50 8.80 7.00 15.90 24.20 0.27 (Ml 0.33 0.46 KAYLO HEAT INSULATING BLOCK is made in all standard sizes, up to 18 in. wide and in thicknesses from 1 in. to 6 in. Where necessary, on special order, the block can be shiplapped for I broken joint, single-layer application in WRITE FOR LITERATURE ON KAYLO HEAT INSULATION Flexible--Cotton batt may be ex panded or contracted to fit any enclosure. Compiled from Chapter 9. .. indicates temperature conductivity. . 1474 thicknesses of 3 in. or greater. 1475 i-' Insulation Insulation Co. ** INdepmdmdenc.ce 8-8800 2727 Irving Park Road, Chicago 18, 111. "Sprayo-Flake" is a multiple purpose insulation providing the utmost in ther mal insulation--noise reduction--con densation control--sealing against air infiltration, etc. VERSATILITY: Sprayo-Flake Insula tion is a versatile product produced from fibrous insulation materials and adhe sives suited to simultaneous SprayoFlake Insulation Gun application to structural surfaces haying regular or irregular centers, spacing or contours. SPRAYO-FLAKE PROCESS: It is made . in 10 standard types and is unique in that it is fabricated and applied in one single, efficient, economical operation on Sprayo-Flake triple-purpose insulation combining 'dampproofing, insulation, and vapor seal in one tailor-made application on wood furred brick trail. the job. The Sprayo-Flake Insulation Process consists of forcibly projecting, through a specially constructed Sprayo- Flake Insulation Gun, dry fibrous mate rials simultaneously with an atomized adhesive. The adhesive primes the sur face being treated and coats the fibers as they leave the nozzle of the Sprayo- Flake Insulation Gun, causing them to build up in a homogeneous, light weight, bonded, cellular insulation coating on the structural surface treated. "Air - Gun - Applied" Continuous "Bonded-On" Insulation Coatings for Steel, Brick, Aluminum, Cement and Sprayo-Flake insulation on air conditioning and healing and air conditioning ducts. Cinder Block, Cement and Asbestos Board, Gypsum, Precast Cement Tile, Wood Sheathing and Roof Decks, Con crete Slabs and Walls etc., in thickness of in., 1 in., 1J4 in., etcTHERMAL INSULATION APPLICA TION: On Masonry Construction Sprayo-Flake Insulation is the ideal in sulation for masonry walls because it is bonded securely to the wall surface treated providing highly efficient life time insulation and at the same time sealing the wall against air infiltration. The emulsified asphaltic adhesive used in applying Sprayo-Flake Insulation is Sprayo-Flake insulation on Concrete Walls and C'cjjings below grade with Aluminum Overcotc on Walls and Ceiling of Fur Storage Vault. one of the finest damp-proofing agents known to the construction science. ON STEEL CONSTRUCTION Sprayo- TYPICAL SPRAYO - BATT INSTALLATION Flake Insulation is especially well Siding -j building Papei--i Sheathing - adapted to use on all types of metal buildings. Being plastic in nature, it bonds and conforms to the surface of the outer covering without cutting and fit ting. These properties provide substan tial savings in both installations and maintenance throughout the life of the building. Seals joints--eliminates con -Studding Lath and Plaster - Note how Sprayo-Flake Insulation builds up and seals the juncture at framing members. densation. Sprayo-Flake *K' factor 0.10 Blu 1476 Insulation Insulation Go. INdependence 8-8800 2727 Irving Park Road, Chicago 18, 111. The Sprayo-Flake Bonded Insulation Mat is applied to the required thickness to the inside surface of the metal roof decking or sheet metal walls. SprayoFlake Insulation is usually applied around exposed purlins in a in. to % in. thickness. ON WOOD CONSTRUCTION SprayoFlake Insulation is bonded directly to wood sheathing, roof decks, etc. The Sprayo-Flake Insulation Mat covers all cracks and crevices and it not only pro vides a highly efficient insulation but it also seals the exposed surfaces against cold and warm air infiltration. SPRAYO-FLAKE "SPRAYED-ON" IN SULATION is ideal for Housing Proj ects, Homes, Industrial Plants, Defense Projects, Storage Tanks, Dust Collec tors. Fur Storage Vaults, Auditoriums, Hospitals, Laboratories, Schools, Ho tels, Flight Wind Testing Tunnels, Radio and Television Broadcasting Studios, Churches, Office Buildings, Commercial Buildings, Apartment Buildings, Cold Storage Plants, Libraries, Warehouses, Cafeterias, Machine Shops, Banks, Pub lic Utility Buildings, Dairy Buildings, etc. SOUND INSULATION: Sprayo-Flake Insulation is a very effective sound dead ening insulation when applied directly to one side of the sound transferring membrane. Tests were made by the C. F. Burgess Laboratories on floors and walls before and after being treated with Sprayo-Flake Insulation in actual struc tures. Sprayo-Flake data booklet 10A on request. SPRAYO-FLAKE PLASTERBASE ON MASONRY WALLS Brick Wall Gypsum Block Wall Brick Veneer Over Hollow THe 1477 Stone Wall I N Insulation The Pacific Lumber Company 100 Bush Street, San Francisco 4, Calif. 35 Bast Wacker Drive, Chicago 1, 111. JR? INSULATION PROVIDES EFFICIENT INSULATION 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 Insulation Manual WRITE FOR . THESE TECHNICAL AIDS One of many installation details shown in Palco Wool Cold Storage Manual 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. ENGINEERING REPORTS--on-thejob findings on actual installations. 1478 Insulation Wood Conversion Company Dept. 220-2 First National Bank Building St. Paul 1, Minnesota NEW- YORK CHICAGO DENVER BOSTON KANSAS CITY 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 belund 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. K-25* Fiber Pneumatic System--The modern, high-speed, automatic way to insulate domestic refrigerator cabinets and doors. Fluffed to proper low dens ity in the manufacturer's plant, K-25 is blown into cabinets and doors under high pressure, forming a tightly felted insulating mat without joints, lamina tions or voids. Tuffiex*--A soft, felted blanket materi al made from fleecy wood fiber, combines high insulating efficiency with toughness and exceptional resistance to heavy im pact blows. Tuffiex is light in weight and nonabrasive--will not tear or pull apart even when cut into narrow strips. Tufflex is available in rolls or sheets of vari ous thicknesses and widths. Applying Nu-Wood Interior Finish A pplying Balsam-Wool Sealed Insulation NU-WOOD* STRUCTURAL INSULATION Nu-Wood Interior Finish--A multiple- Nu-Wood Sheathing--A strong, struc purpose wood fiber material available in tile, plank and board. Nu-Wood insu lates, decorates and quiets noise. NuWood's colors are soft and harmonious-- tural insulating sheathing in in. and 25/32 in. thickness, asphalt impregnated, offering complete moisture protection. will not fade. The Nu-Wood interior finish line includes Sta-lite, an insulating interior finish with more than 70 per cent light reflection. Nu-Wood Roof Insulation--Will fill all requirements of Federal specification LLL-F-321b. Furnished in any prac tical thickness. Reg. U. S. Pat. Off. M-47-71G9 1479 Insulation ReflwtiTM American Flange & Manufacturing Co. Inc. 30 Rockefeller Plaza, New York 20, N. Y. Plaza 7-2200 TerroTherm 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. Permanent, Fire-Proof Insulation 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 ot 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 as thick. 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 are 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 pers'onnel. In these chambers, temperatures as low as -- 125F were maintained, with a tem perature drop of +70F to --70F in 10 to 12 min. 1480 Insulation Window Screens Ingersoll Products Division Borg-Warner Corporation 321 S. Plymouth Court, Chicago 4, III. Koolshade* sunscreen is a bronze min iature Venetian blind with fixed hori zontal bars set at an angle which will keep the greatest possible amount of solar 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 account for as much as 75% of the cooling necessary in air conditioning installations. 100 sq ft of Koolshade is equal to 1 ton of refrig eration and costs to % as much. Koolshade provides insect protection equal to ordinary insect screen. Koolshade is framed and applied to windows like ordinary insect screens. Ingersoll distributors can apply Kool shade in patented Koolshade aluminum frames, in Koolshade Quik-on frames which have only top and bottom frame rails held apart in tension by installation hardware or in wood or metal frames. Ingersoll's Sungard* economy sunscreen stamped from aluminum sheet, is in tended for industrial applications and performs the same heat load reducing function as Koolshade at lower cost. Sungard is not insect proof. Sungard is framed and applied by Ingersoll Distributors like Koolshade. 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's Ingersoll Koolshade Solar load transmitted through bare windows 116 Btu x 384 sqft................................................. 44,544 Solar load transmitted through Ingersoll Sungard Solar Load through KOOL SHADE......................................... 7,920 KOOLSHADE 11.5 Btu x 384 Reduction................... ..................... 53,280 sqft.................................................. 4,416 in Tons 4.440 Amount of Solar Heat stopped by KOOLSHADE............................... 40,128 Expressed in tons of refrigeration (12,000 Btu's--1 Ton) 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 12:00 noon Peak Load: Btu's Heat stoppage equals Tons 3.3444 Solar Load through Bare Windows 15,096 Follow same procedure for 15 West Solar Load through KOOL- _ Windows 4 ft x 6 ft--total square footage SHADE.......................................... 1,224 360 sq ft--and using 3 p.m. Peak Load: - Btu's Solar Lead through BareWindows 61,200 Reduction......................................... 13,872 in Tons 1.156 Total tons of refrigeration saved 8.9404 Write to Ingersoll Products Division, Borg-Warner Corporation. Dept. V for lechnical Information. 1 Ex&niple'based on test data from ASHVB GUIDE, 1940. * Koolshade and Sungard are trademarks (Reg. U-S. Pat. Off.). They are the property of the Ingersoll Steel Division, Borg-Warner Corp- - 1481 Insulation Infra Insulation, Inc. 525 Broadway, New York, N. Y. - - Telephone: WOrth 4-2241 "" THERMAL FACTORS OF INFRA INSULATION AND DRY ROCKWOOL EQUIVALENTS Type 6 Type 4 Jr., in ONE-INCH Space Up-Heat C.089 R11.23 = 4f" dry rockwool. Up-C.194R 5.15 = 2" dry rockwool Wall-Heat C.073R13.69 = 5f" dryrockwool. Wall-C.150R 6.66 = 2f" dry rockwool Down-Heat C.044R22.72 = 9" dry rockwool. Down-C.097R 10.30 = dry rockwool Infra Insulation, Type 6, is a tough 3-aluminum-sheet insulation, with 6 beat-ray- reflective surfaces, plus two outer 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. The normal installation rate between wood joists is 2,000 sq ft a day. The If cu ft carton contains 500 sq ft, weighs 40 lbs. Standard width, for 12 in., 16 in. and 24 in. centers. Standard Type 4, for 12 in., 16 in., 24 in. centers. . i Heat flow through wall space, which is air, is 5 per cent to 7 per cent by Conduction; 15 per cent to 28 per cent by Convection; and by Radiation, 65 per cent to 80 per cent. ABSORPTIVITY and RADIATION:--Each of Infra's 6 aluminum surfaces THROWS BACK 97 per cent of the heat rays which strike it. As emittive surfaces, Ki they emit ONLY 3 per cent of heat actually absorbed by conduction, convection and radiation. Practically all building materials, including ordinary insulations, absorb and emit 90 per cent of heat rays, against Infra's 3 per cent. CONDUCTION:--One sq ft of Type 6 Infra weighs only 1J os, has only If cuin. mass. The ratio is 1 of Infra mass to 431 of low conductive air. Ordinary insulation, when dry, has a ratio of 1 of mass to 23 of air. CONVECTION and VAPOR:--Each of the 3 tough aluminum sheets of Infra has ZERO permeability to all gases, including heated air, cold air, and water vapor. 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, reverse, triangular, reflective air pockets. The . construction, and the lack of weight for heat exchange, make Infra Insulation abso lutely non-condensation forming. Neither can it absorb nor store moisture. Infra Insulation uses 99.5 per cent pure .0009 in. and .002 in. aluminum, made in accordance with special Infra emissivity requirements. It has 17 lbs and 52 lbs bursting strength (Mullen test), 800 per cent to 2600 per cent greater than ordinary foils. The tearing strength is 28 grams and 80 grams (Elmendorf test). The special fiber separators are permanently flame-proof, mold-proof, and vermin-resistant. FIRE:--Since Infra emits practically no heat rays, and since aluminum's melting point is 1250 F, it has actually prevented the spread of fire. . SANITARY:--Infra is sanitary, inhospitable to vermin, and DOES NOT RETAIN 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 (|) inch in depth. Can be used in 1 in. spaces be tween furring strips; in brick or masonry walls; around metal ducts; and under floors, ordinary or radiant heated. Write for new 56-page authoritative manual, "Simplified Physics, of Vapor and Thermal Insulation." Insulation ALF0L INSULATION Manufactured by Reflectal Corporation 155 East 44th Street New York 17, N. Y. HEAT INSULATION for ALL PURPOSES Alfol Building Blanket--for sail Types of Building Structures. Alfol Building Blankets consist of spaced layers of Alfol Aluminum Foil Insulation attached along the edges to a liner sheet of heavy vapor proof paper. Packaged in handy rolls of 250 sq ft each for use on 12 in., 16 in., 20 in. or 24 in. centers. Weighs less than Vio lb per sq ft. High Insulating Efficiency Positive Vapor Barrier. Low Heat Storage Capacity. Negligible in Weight. Moisture Proof. Durable. Odorless and Clean. Easily Applied. Low Cost. . Specifications Handy Package--SoO Sq Ft of Insulation Description Type I -- 1 Layer ALFOL Type II.-- _ 2 Layers ALFOL Type III -- 2 Layers'ALFOL Type IV.-- ^ 3 Lavers ALFOL Widths Net Area Net Weight per Roll per Roll7* 12'-16'-24' 250 sq. ft. 17 lbs. 16*-20*-24* 250 sq. ft. 10 lbs. 12#-16#-24* 250 sq. ft. 20 lbs. l6'-20*-24' 250 sq. ft. 23 lbs. ALSO ALFOL PREFABRICATED INSULATION PANELS For Tanks, Towers, And All Types of Heated Equipment. ALFOL ASBESTOS . Alfol Aluminum Foil Insulation Laminated To Asbestos For Ovens, Ranges, Boiler Jackets, Hot Water Heaters, And All High Temperature Insulation Purposes. ALFOL JACKETING Heavy Reinforced Paper Combined With Alfol Aluminum Foil. Provides Insula tion And Vapor Barrier In One Convenient Form. For Refrigerator Cars, Trucks, Buses, Trailers, Etc. Write for complete information, catalogs and prices, 1483 Silvercote Products, Inc. 161 East Erie Street, ChicagorDl. S I L V i: K C O T E 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 with 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 gf - the framing members to form an air space between the insulation and the exterior sheathing. The water vapor perme ability of Silvercote Simplex is 99.2 grains per sq ft per hour per inch of mercury vapor pressure difference. 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. The oppo site side of this type of reflective blanket is a plain kraft finer perforated where necessary to allow compression packag ing and also to assure ample water vapor permeability at the so-called breather side of the blanket. Reflective Blanket, Silvercote on Breather Side--This product was developed for application m structures where only one air space adjacent to the cold side of the blanket is available. An air space faced on one side with a Silvercote surface will have approximately equal effectiveness whether formed on the vapor barrier or the breather side of the blanket. Since Silvercote paper is in itself not a vapor resistant material, it can readily be used on either side of blanket insulation. Reflective Blanket, Silvercote on Both Sides.--A de luxe insulation material utilizing the maximum 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 "U" 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. Testing Laboratory United States Testing Company, Inc. Est. 1880 Main Laboratories 1415 Park Ave., Hoboken, N. J. Philadelphia, Pa.--Chicago, III--Los Angeles, Calip.--Denver, Colo.--New Yoke N. Y.-- Providence, R. I.--Boston, Mass.--Memphis, Tenn.---Dallas, Texas ' * * The United States Testing Company, Inc., is one of America's leading independent testing and research laboratories. Established in 1880, it is today an institution known and recognized from coast to coast--an institution whose scientific findings are accepted as impartial and authoritative by every branch of American industry. Thermal Transmission A pparatus For mminnp thermal conductivity of rigid, semi-rigid or loose types of tnttxlating materials. Boiler Testing We have all the necessary equipment to test and rate heating boilers in accordance xoith 1-B^R--SBI--ASME Codes A ir Filter Duct Testino. Our Engineering Laboratory is equipped with all the necessary appara tus to conduct tests on domestic heating boilers for determination of fuel con sumption, draft-loss, stack temperature, steam quality, Btu output, flue gas analysis, and over-all efficiency. Rating tests are performed according to either the SBI or I=B=R codes; as well as under simulated operating conditions for development purposes. Water heaters can be subjected to capacity tests under wide temperature requirements and varied heating loads. Refractories, fuel additives, valves, pumps, burners, and heating accessories of many types are evaluated scientifically in our laboratories. Other facilities include all the neces sary equipment for conducting exhaus tive tests on air cleaning devices according to accepted impingement or the more recent discoloration methods. These tests may be performed with either artificial or natural dusts, under an almost infinite variety of flow rates and dust feed. Diffusers, grilles, registers, and duct ventilators are regularly tested and rated. SOUND MEASUREMENTS Measurements of sound absorption and sound transmission coefficients are but two of the typical tests made on a great variety of building materials. Field and laboratory tests are regularly conducted for determination of sound intensity in the audible range. Our experts are available for court testimony in connection with any of the tests we perform, in support of our findings. Write for Descriptive Literature and Price List. 1485 V / -- Publications American Society of Refrigerating Engineers 40 West 40th Street, New York 18; 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 35 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 $5.00. CODES AND STANDARDS 10NG acknowledged the most au- ASRE further contributes to refrigera J 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 Basic 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 81 different applications. A must for the design ot commercial 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 6J4 in. x 9 in. 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 IT is the policy of the ASRE to treat in its meetings current subjects touching upon all phases of the art of refrigeration. Membership is in several grades with dues from $10 to $18. Sec tions hold meetings in 31 principal cities. More detailed information will be sent on request. To keep apace with progress in refrigeration and air conditioning, read the publicity lions and follow the activities of the AMERICAN SOCIETY OF REFRIGERATING ENGINEERS. *0 West 40th St., New York 18. N. Y. 1486 Publications Coal-Heat Published at 20 W. Jackson Blvd., Chicago 4, Illinois Phone Wabash 2-9464 New York City, MUrray Hill 2-9192 Editorially . COAL-HEAT puts its emphasis on: --ways and means of furthering the more satisfactory use and sale of coal.--sales and servioe--heating merchandising--the fundamentals The `Equipment Situation'-- Three times.out of four the fuel dealer has two strikes against him because of the design, condition, and operation or the equipment in which much of his coal is used. For instance, findings of the Coal Heating Service inspection campaign in Minneapo lis and St. Paul, Minn., covering thousands of individual homes show that: 1. Only one heating system in 10 is in good condition. 2. More than 2 out of 3 need cleaning. 3. More than 3 out of 7 have chimneys or smoke pipe that need attention or re placement. In the larger field--among the nation's laundries, dairies, hotels, hospitals, apart ments, schools, churches, medium and larger sized plants the reader can assume from detailed records of plant inspections of such fuel users in Akron, Canton, Cleveland, Middletown, Ohio; Detroit, Flint, and Lansing Mich.; Durham, N. C.; Altoona and Erie, Pa.; Milwaukee, Minneapolis and St. Paul, Morgantown W. Va., Toronto, Canada, and Wheeling, W. Va., that `on the average' out of every 100 such plants: --from 20 to 80% are mechanically defective; --from 10 to 20% are obsolete; --from 10 to 15% are overloaded; --from 20 to 80% are improperly operated; Obviously, therefore, in all too many cases --far too much fuel is wasted; --heating or power costs are excessive; --heating and operating problems are far too frequent; --the modernization and replacement market is all but unlimited. So, if the reader recognizes this situation there can be no question as to COAL-HEATS place in the picture from the sales and service viewpoint. Functionally, the 477 feature articles and regular departments `indexed' in COALHEAT the past 12 months were divided as follows: Association News Business Trends. . Coal Handling.... Collections............ Costs....................... Credits................... Equipment.......... Fuels..................... Fuel Engineering. Heating................ Housing............... Markets............... New Products. ... 19 Operation & Maintenance................... 13 22 Personal Relations................................. 8 16 Personnel................................................... 22 13 Research.................................................... 20 18 Sales............................................................ 24 30 32 13 23 22 21 Salesmanship............................................ 33 Sales Promotion....................................... 23 Service....................................................... 25 Smoke Prevention................................... 26 Training Activities.................................. 26 each of these being covered as 14 briefly and helpfully as possible. 1487 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 has won ten major national editorial achievement awards in ten years--a record unsur passed by any business publication in any field. Editorial content 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 condi tioning, plumbing and allied products. 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 ijames and complete catalogs of leading manu facturers. . Published annually. 1952 Edition, $7.50. 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. 1488 Publications The Industrial Press 148 Lafayette Street, New York 13, N. Y. Telephone: Canal 6-8120 Heating and Ventilating Engineering magazine for the men toho ' 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. First twelve issues brought more than 87,000 requests for information about specific products such as: Boilers, furnaces, gas-burners, oil-bumers, toilets, sinks, pipe, fittings, valves, pumps, pipe-cutting and thread ing tools, hot water heaters, room coolers, water softeners, fans, blowers, controls, insulation, and many others. Sample copy and advertising facts upon request. Subscription rates in X]. S. and Canada; One year, S3; two years, SB; three years, tS. In all other countries, SB .' per year. 1489 / KEENEY PUBLISHING COMPANY 6 North Michigan Avenue, Chicago 2, 111. Publications Sheet Metal Worker Published by Edwin A. Scott Publishing Company 92 Martling Ave., Tarrytown, N. Y. Publications PLUMB! HD *x HEHf HEATING JOURNAL 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 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. 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 warm air heating, air conditioning, and sheet metal products and equipment, which lists all products, their trade names, and the manufac turers' addresses. The key man in the residential air con ditioning picture is the warm air heating 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.--A.B.C. Subscription Prices--U. S. tS per year. Subscription Prices--U.S. tS per year. Canada, Central and So. America--14-00 per year. Elsewhere S6 per year. 1490 rales--13.00 per year, U. S.t Canada and Pan A mer. Foreign 94.00. Ad vscerritxiseimng raaclees on request. Subscription rates--13.00 per year, U. 8., Canada and Pan A mer. Foreign 94.00. Ad vertising rates on request. THE January 1952 issue of Sheet Metal Worker was its 78th Anniversary and 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 Co. Subscribers are mainly merchandisin contractors purchasing practically all products and equipment which they fa iricate, erect or install. Manufacturers, jobbers and distributors also subscribe. The market has three main 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 the Audit Bureau of Circu lations, and Controlled Circulation Audit, Inc. Over 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 Co., Inc., Publishers 92 Martling Ave., Tarrytown, N. Y. PLUMBING and Heating Journal is edited to furnish a well-rounded, efficient service 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. 1491 Publications Snips Magazine 5707 W. Lake St. Chicago 44, HI. While distributed in 48 States and widely in Canada, the shaded area of the map shows where'SNIPS* circu lation is most intense. It's the area where warm air heat predominates and where sheet metal work, in all its branches, has made its greatest strides. ' READER INTEREST SNIPS is packed each month, from cover to cover, with hundreds of live news stories and exclusive pictures of the trade it serves. No long contributed stories. It's all field gathered material, secured the hard way, rubbing shoulders with the readers. Such work gets for the periodical a reader interest seldom found in a trade publication. You'll find this feature the basis of the sensa tional inquiry pulling power and sales producing value of advertising space in SNIPS. This live, friendly, close to the reader periodical "continues to go places" in reader interest, intense coverage and trade popularity. An effective medium preferred by many Notable Industrial Advertisers year af ter year, and many Prominent Jobbers who know their market well. We maintain our fine lists of known, reputable buyers, through constant co operative work with the jobber trade of the industry. _ Packed each month with practical appli cations of the latest advancements in the Sheet Metal, Heating and Engineering Field. DON'T MISS OUR SPECIAL ISSUES January Annual Issue--March Anniver sary Spring Market Issue--September Fall Market Issue--December Holiday Greeting Issue--Further information gladly sent on request. During the past year over 350 firms used space with us. These valued patrons see in our 13,000 readers, a carefully selected and substantial buying group, wor thy of "talking to" month after month. Rates for space have always been conservative. 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, by any standard of comparison. ABOUT SNIPS' MAILING LIST It's truly a select group that gets SNIPS. They are the outstanding firms and individuals in the trade whom the better supply houses are selling or trying to sell. They are the contracting and installing concerns whom the principal jobbers and distributors of the industry--people.who really know their territories best--consider worthy of cultivation by mail, promotion and salesmen's calls. These advertising people will be alert to serve you. H. F. Hoy, Nick Carter, Jay Barton and Ed Carter in the Home Office. In the East, Snips Magazine, 501 -I iftd Avenue, New York 17, New York, Murray Hill 2-9192. In the West, Kimball-Menne Company, 1052 W. 6th Street, Los Angeles 17. California, Madison 6-9395, and Km. 767 , 681 Market St., San Francisco 5, Calif., Yukon 6-4588 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 climate 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 Soci ety of Heating and Ventilating Engineers now numbers over 8500 members, whose express purpose is to improve the Art through the inter change 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, Jun ior, 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 on the Council for 1 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 per manently 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 funda mental principles of heating, ventilating and air conditioning, is located at 7218 Euclid Ave., Cleveland 3, Ohio. In September, 1894, a little group of nationally known engineers, educa tors 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 modem engineering. These keen, alert, progressive men knew that the methods and equip ment 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 themselves 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 enterprise 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 un furled the banner of The American Society of Heating and Ventilat- 1493 ing Engineers, thousands ,of the real leaders of thought and action in heating, ventilating, and air conditioning have gathered about that stand ard and carried it proudly before them far along the way of outstanding accomplishment. They may be identified among engineering 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. A. S. H. V. E. RESEARCH LABORATORY Since 1919 The American Society op Heating and Ventilating Engineers has maintained a permanent research staff and facilities devoted solely to the study of fundamental problems in the field of heating, ventilating and air conditioning. During the past quarter century much has been done to advance the art by estab lishing scientifically sound data which the engineer can apply in the design, opera tion, and maintenance of heating, ventilating, and air conditioning systems and equipment. For twenty-five years the Society's Research Laboratory was located at the U. S. Bureau of Mines Building, Pittsburgh, Pa. The Laboratory was moved to Cleveland in 1944, and early in 1946 the Society purchased premises at 7218 Euclid Avenue. In addition to work at the Society's Laboratory, a substantial part of the research pro gram has been carried on through the medium of cooperative agreements with leading educational institutions 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. The research activities are financed from Society funds, of which a portion comes from membership dues and from its publications, and these funds are ampli fied by contributions from friends in the industries engaged-in the general field of heating, ventilating, and air conditioning. ' The new Environment Laboratory is an important addition to the Society's facili ties for fundamental research. It has been constructed for the development of authentic data for the design and installation of panel heating and cooling. The room is the result of a conference in early 1947 of more than 100 representative engineers from consulting firms, technical societies, universities, trade associations and industry leaders. The group agreed that the Society should take the initiative in acquiring data for panel heating and cooling which were lacking at the time. In June 1947 the A.S.H.V.E. Committee on Research formed a Technical Advisory Com mittee on Panel Heating and Cooling to advise on technical details of this re search. The work was divided into four spheres of activity: 1. Heat distribution within and behind the panel. 2. Heat transfer between the panel and the space.in the room. 3. Comfort conditions. 4. Controls. In order to accomplish parts 2 and 3 of the proposed program, it was decided to construct a full-sized room wherein the temperatures of all the room surfaces might be controlled independently. So that the room could also be used for a study of the relationship between human comfort and radiation, it was designed to permit divi- 1494 sion into two rooms when desired. After two years of planning, construction began in 1950 and was completed in November 1951. . The room itself is 25 ft-by 12 ft with a ceiling adjustable in height from 7 to 12 ft. It can be divided into two separate rooms each 12 ft by 12 ft. The room is housed in . the main A.S.H.V.E. Laboratory and is 3 ft above the main laboratory floor. The interior surfaces of the room are aluminum panels backed by % in. copper coils on 3 in. centers. Outside wall temperatures as low as 0 F can be simulated. Floor and ceiling surfaces can be kept at temperatures as high as 180 F. The instrumentation provided, permits readings of surface temperatures within the room (400 thermocouples attached to back of panels), air temperatures, rate and temperature of infiltration air, and heat picked up or given off by all surfaces. It is intended to add more equipment which will permit maintaining air temperatures within the room, independent of surface temperatures. This will allow human comfort studies under varying internal dry bulb temperatures, relative humidities and air change rates. . It is expected that some of the practical results of the use of this room will be: 1. To measure the rate of the exchange of heat between surfaces of the room and air in the room as they are affected by temperature, humidity, ventilation, etc. 2. To determine the influence of radiation on human comfort, and using this to improve the A.S.H.V.E. Comfort Chart. 3. The use of the room to study the removal of heat by heat absorbing panels. 4. An evaluation of different types and colors of paint and wallpaper on panel performance. . In addition to these projects, the room also provides the A.S.H.V.E. Laboratory with a flexible research tool that should be extremely valuable for many years to come. THE GUIDE A distinctly new service was inaugurated by the Society in 1922 when it estab lished The Guide. Now in 1952, as the 30th Edition of the Heating Ventilating Air Conditioning Guide makeB its appearance, it is notable that The Guide has served effectively not only the membership but the entire profession and the allied industries, and has received world wide recognition as a reliable and authoritative compendium of useful heating, ventilating and air conditioning data. Throughout the 30 years of its service The Guide has become a reference book 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 modern 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 and Industry 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. 1495 THE AMERICAN SOCIETY OF HEATING AND VENTILATING ENGINEERS Headquarters: 62 Worth Street, New York 13, N. Y. (Tel. WHitehall 3-0377) ASHVE Research Laboratory, 7218 Euclid Ave., Cleveland 3, Ohio President....................... First Vice President. . Second Vice President Treasurer..................... Executive Secretary. .. Technical Secretary. .. OFFICERS ... .Ebnest Szekei.y ..........Reg F. Taylor ...............L. N. Hunter J. Donald Kroekeb ... A. V. Hutchinson ............Carl H. Funk COUNCIL Ernest Szekely, Chairman Reg F. Taylor, Vice Chairman - ( Fahnestock, P. B. Gordon, R. T. Kern, D. M. Mills. ox, N. H. Peterson, B. H. Spurlock, Jr.; and B. L. Evans, One Year: J. E. Haines, J. W. James, E. R. Queer, G. B. Supple, L. E. Seeley.- ADVISORY BOARD L. E. Seeley, Chairman; Homer Addams, Lester.T. Avery, M. F. Blankin, S. E. Dibble, S. H. Downs, E. O. Eastwood, W. E. Eleisher, H. P. Gant, F. E. Giesecke, E. Holt Gurney, L. A. Harding, H. M. Hart, C. V. Haynes, D. D. Kimball, G. L. Larson, SI R. Lewis, A. J. Offner, E. B. Rowley, A. E. Stacey, Jr., G. L. Tuve, A. C. Willard, C.-E. A. Winslow, ' and B. M. Woods. COUNCIL COMMITTEES Executive: L. E. Seeley, Chairman; L. N. Hunter, Reg F. Taylor. Sub-Committee: C. S. Koehler, H. E. Sproull, Reg F. Taylor. Finance: J. W. James, Chairman; N. H. Peterson, E. R. Queer, J. Donald Kroeker, Ex-Officio. . Ways and Means: C. E. Price, Chairman; I. W. Cotton, M. K. Fahnestock, A. J. Nesbitt, E. R. Queer. . Membership: J. E. Haines, Chairman; R. T. Kern, D. M. Mills. Program and Papers: E. R. Queer, Chairman; J. H. Fox, P. B. Gordon. Standards: L. N. Hunter, Chairman; B. H. Spurlock, Jr., G. B. Supple. COMMITTEE ON RESEARCH I. W. Cotton, Chairman R. S. Dill, Vice Chairman Cyril Tasker, Director of Research Three Years: I. W. Cotton, W. A. Grant, N. B. Hutcheon, B. H. Jennings, C. O. Mackey. Two Years: A. B. Algren, John Everetts, Jr., R. W. Keeton, M.D., T. H. Smoot,W. N. Withebidge. One Year: Carl F. Boester, R. C. Cross, R. S. Dill, A. J. Hess, H. A. Lockhart. / 1496 sttonSOI OOtS6 06 ll3HN3lWW-3yniVH- S9 HUMIDITY RATIO (W)-POUNDS WATER PER POUND DRY AIR QII Oil SOI OOt CU FT OF AIR PER MINUTE CU F T O F A IR P E R M IN U T E \ FRICTION LOSS IN INCHES OF WATER PER IOO FT FRICTION OF AIR IN STRAIGHT DUCTS HEATING VENTILATING ! AiFl CONDITIONING GUIDE COPYRIGHT 1951 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. CAUTION: DO NOT EXTRAPOLATE BELOW CHART.