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SC-ASHVE-013 ican Society of Heating and tilating Engineers eating ventilating air ditioning guide. OL 14 19 St 628.8 AMERICAN 21718 76902 X594507 This Book Shall Not Be Taken From The Library. Oo 'V cA v..KiV1: f JV) Sr. Louis Public Library ve/O H vt+y I t The American Society of Heating and 'Ventilating Engineers GUIDE 1936 ' FOR HEATING, VENTILATING, AIR CONDITIONING i 1 An Instrument of Service prepared for the Profession--Containing a j Technical Data Section OF reference material on. the desicn and specification of heating, VENTILATING AND AIR CONDITIONING SYSTEMS---- BASED ON THE TRANS ACTIONS--the Investigations of the Research Laboratory and Co operating Institutions--and the Practice of the Members and Friends of the Society ' tocether with a Manufacturers' Catalog Data Section , Containing Essential and Reliable Information Concerning Modern Equipment ALSO The Roll of Membership of the Society WITH }' 'Complete Indexes> .; :\ ,, / .\ ' '' to Technical a\io Catalog Baja-. Sections . Yol. 14 $5.60 Per Copy V X594507 - Published Annually by I American Society of Heating and Ventilating Engineers 51 Madison Avenue New York-,'N. Y. ' .'rr^wpb'-..jr: ! -r^-1 Copyright, 1936 . by the American Society of Heating and Ventilating Engineers ' AND BY IT Dedicated To the Advancement of The Protession . 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 ' The Horn-Shafer Company BALTIMORE MARYLAND H .3 ^ v 5 vs "T?eJp. 6*2.8.* V) PREFACE TO THE 14th EDITION. T$3 i* HE Guide Publication Committee has incorporated in the four teenth edition of The American Society of Heating and Venti lating Engineers Guide many new and important additions to the Technical Data Section which extends its usefulness to all those indi viduals who are interested in the professional art of heating, ventilating and air conditioning. The original conception of the founders of The Guide has been carefully protected in this new volume so as to maintain its continued role as an authoritative and unbiased presentation of long established, as well as newly recognized scientific standards of the profession and allied in dustries. . Because of increasing demands from various users.of The Guide, and because of increased application of air conditioning and cooling to all types of industrial processing and comfort installations, four new chapters have been added to the Technical Data Section on the subjects of Refrig eration, Drying, Motors and Their Control and Railway Air Conditioning. All of the principle thermodynamic cycles of cooling adaptable to air . conditioning are concisely described and illustrated in the new chapter on Refrigeration and in addition complete tables of the common refrigerants are included. Dryer design and methods of construction are given with proper control mechanism for adequate and desirable drying results. A \ ' new temperature and humidity chart which may be applied to all types of dryer calculations with a complete descriptive example is fully described. ' Electric motors and their proper adaptation to all types of applications for fans, filters, pumps, hoists, compressors, stokers, oil burners and other; . units used in heating, ventilating and air conditioning 'installations are discussed in the chapter on Motors with recommendations for. 'Control . devices accomplishing convenient and effective regulation. All of the. several complicated features involved in the design of passenger car ' railway air conditioning are amply discussed in a new chapter on this subject. A typical example is given involving the many factors which should be considered in the calculation of the cooling load for a passenger car. Curves and tables showing the costs per car mile for various types of cooling systems are given with cost equations which take into account the various mechanical efficiencies applicable to tractive power. In addition to this new material all of the previous chapters have been carefully checked and reviewed and in some cases the text has been com pletely rewritten.- Information onjjnit heaters, ventilators, coolers and air conditioners has been, correlated in one chapter and completely revised. Two methods of estimating fuel consumption are discussed in the new chapter on Heat and Fuel Utilization. 'System characteristics of fans with curves to illustrate the effects of sp.eed or system changes on'fan ' operation have been added. Other chapters which have been amplified " with much new material are: Cooling Methods, Industrial Exhaust Systems, Automatic Fuel Burning Equipment, Radiators and Gravity Convectors, Pipe, Fittings, Welding, Water Supply Piping, Water Heating, Electrical Heating, and Air Conditioning for Industrial Processes, # 's An additional feature of The Guide 1936 is the new table of saturated water vapor extending over a range from minus 130 to plus 200 F with heat content values based on the varying values of specific heat for air. As a result of a comprehensive survey of cities in the United States and Canada, a table has been added giving the maximum city water main temperatures. The degree-day table has been amplified so as to segregate the monthly values for each city. Basic and fundamental data which have been added to The Guide each year since its inception in 1922 has been retained with additions from research sources made necessary by the progress of the heating and venti lating art. The Problems in Practice which were a major innovation of the last edition of The Guide have been retained with new and practical examples to expand and amplify the text matter of each one of the 44 chapters. Over 60 new illustrations, curves and charts have been added which, enhances the value of the descriptive text material. The increasing demand for copies of this book by universities, engi neering and technical schools for student instruction indicates its recogni tion as the standard authority in the field of heating, ventilating and air conditioning. In connection with the manufacturers' Catalog Data Section the Com mittee has made a more determined, effort, to carry out the original . conception of having the descriptive material as free as possible from comparative statements and superlative terms, and to present therein such condensed technical information concerning modern equipment as will be of practical value to the user of The Guide. In general, the manufacturers have cooperated fully to make their data useful, informa tive and serviceable, so that the user can apply it effectively in the selection of materials or equipment to be used in general design. The Committee appreciates the aid of those far-seeing manufacturers who have assisted in this cooperative enterprise to advance the art of heating, ventilating and air conditioning which so vitally affects the comfort, happiness and health of everyone. In 1936 it will be possible to distribute The Guide to more than 12,000 users and it is extremely gratifying that a . greater number of manufactuers recognize the effective service rendered by this reference volume and have increased their advertising space iri order to carry the story of their products in greater detail to the thousands 1 who use this book. . It is felt that a careful study of both text and catalog data pages will amply reward the user who desires to obtain reliable data in convenient. form and it is hoped that the brevity and simplicity of the presentation. 1 will impress the user who requires a volume for quick reference. ' The Committee releases this fourteenth edition of over 12,000 copies with the sincere hope that it will receive the same generous reception that was accJorded to its predecessors and that users' will find it the most valuable reference volume in their library. , jj , Chairman GUIDE PUBLICATION COMMITTEE IV EDITORIAL ACKNOWLEDGMENT SINCE 1922 The Guide has held an enviable record as an authoritative reference volume .for the heating, ventilating and air conditioning profession and its allied industries. Each year the Guide Publication Committee invites and receives .the helpful assistance of hundreds of' engineers and technicians who have in the past given willingly of their time and knowledge to improve the advancement of the profession. It is with a profound feeling of appreciation that this Guide Publication Committee gratefully acknowledges the cooperative efforts of the follow ing individuals who have contributed generously to the improvement ofthis 1936 edition. T. N. Adlam J. J. Aeberly O. W. Armspach C. L. Arnold C. M. Ashley - W. R. Beattie E. H. Beling J. L. Blackshaw . M. G. Bluth C. A. Booth Albert Buenger W. H. Carlton Sabin Crocker D. N. Crosthwait, Jr. J. M. DallaValle John Everetts, Jr. J. R. Hertzler E. L. Hogan. J. H. Holton F. C. Houghten Prof. C. M. Humphreys - ` , . H. F, Hutzel C. F. Kayan R. T. Kern R. E. Keyes Prof. V. O. Knudsen J. W. Kreuttner C. H. Lankford L. L. Lewis , Prof. Axel Marin T. A. Marsh . H. C. Murphy Prof. D. W. Nelson P. Nicholls R. F. Norris A. J. Offner ; O. W. Dtt J. S. Parkinson G. C. Polk E. C. Rack H. G. Rappolt Prof. T. F. Rockwell C. Z. Rosecrans J. O. Ross S. I. Rottmayer Prof. F. B. Rowley S. S. Sanford Prof. W. M. Sawdon Prof: L. E. Seeley C. G. Seqeler H. C. Sharp J. >. Smith . A. E. Stacey, Jr. B. Steele , D. J. Stewart . C. A. Thinn . W. D. Turnbull G- H. Tuttle J. H. Van Alsburg' H. A. Wagner A. R. Walker W. K. Walker Prof. C. P. Yaglou Those individuals who constantly use The Guide and members of the Society are especially indebted to those engineers who have aided in the preparation of this edition and the Guide Publication Committee hereby expresses its sincere appreciation for the loyal cooperation of the several contributors to' this volume. GUIDE PUBLICATION COMMITTEE G. L. Larson, Chairman . . S. H. Downs W. W. Timmis E. A. Jones J. H. Walker E. N. McDonnell W. L. Fleisher, Advisory John James, Technical Assistant . CODE of ETHICS for ENGINEERS NGINEERING work has become an increasingly important factor E in the progress of civilization and in the welfare of the community. The engineering profession is held responsible for the planning, construc tion and operation of such work and is entitled to the position and authority which will enable it to discharge this responsibility and to fender effective service to humanity. That the dignity of their chosen profession may be maintained, it is the duty of all engineers to conduct themselves according to the principles of the following Code of Ethics: .. 1-- The engineer will carry on his professional work in a spirit of fairness to employees and contractors, fidelity to clients and employers, loyalty to his country and devotion to high ideals of courtesy and personal honor. _. f. 2-- He will refrain from associating himself with or allowing the use of his: . name by an enterprise of questionable character. 3-- He will advertise only in a dignified manner, being careful to avoid misleading statements. ..... 4-- He will regard as confidential any information obtained by him as to the business affairs and technical methods or processes of a client or employer. 5-- He will inform a client or employer of any business connections, interests or affiliations which might influence his judgment or impair the disinterested quality of his services. ' 6-- He will refrain from using any improper or questionable methods of soliciting professional work and will decline to pay or to accept com missions for securing such work. . 7-- He will accept compensation, financial or otherwise, for a particular service, from one source only, except with, the full knowledge and consent of all interested parties. 8-- He will not use unfair means to win professional advancement or to injure the chances of another engineer to secure and hold employment. 9-- He will cooperate in upbuilding the engineering profession by exchang ing general information and experience with his fellow engineers and students of engineering and also by contributing to work of engineering societies, schools of applied science and the technical press. JO--He will interest himself in the public welfare in behalf of which he will . . be ready to apply his special knowledge, skill and training for the use and benefit of mankind. vi CONTENTS THE A.S.H.V.E. GUIDE 1936 Page Title Page................................................!..... .................................................... ................ ________ i Preface......................................................... ;................................................................................. . iii Editorial Acknowledgment................................................1............................................. ...... v Code of Ethics for Engineers........................ :..................... ............................................ . vi Contents....:..................................................... ............... ............................ ........................ ............ vii Index to Technical Data.......................................................................................................... viii Chapter 1. Fundamentals of Heating and Air Conditioning-..... .................................. 1 Chapter 2. Refrigeration................................................................................ ......................... 37 Chapter 3. Ventilation and Air Conditioning Standards:... ........................................... 57 Chapter 4. Natural Ventilation................................. _........................................................... 89 Chapter 5. Heat Transmission Coefficients and Tables................................................. 103 Chapter 6. Air Leakage........................................ ...............:....................:............................... 131 Chapter 7. Heating Load........................ .................................................................................. 143 Chapter 8. Cooling Load...... ................................... .......................... ...................--................ 157 Chapter 9. Central Air Conditioning Systems............................................................... 169 Chapter 10. Cooling Methods................................................................................................. ,.. 179 Chapter 11. Humidification and Dehumidification............................ ................................ 201 Chapter 12. Unit Heaters, Ventilators, Coolers and Air Conditioners........................ 217 Chapter 13. Railway Air Conditioning.... ................................ ................................-............. 257 Chapter 14. Temperature and Humidity Control.......... ..... ............... ............................._ 269 Chapter 15. Air Pollution.............................................. ........ ..................................................... 287 Chapter 16. Air Cleaning Devices.......................................................................... : .......... 299 Chapter 17. Fans.............................................. ......................... ....... .................1....................... 309 Chapter 18. Sound Control.... ....................................................................................................! 325 Chapter 19. Air Distribution........................................................... ........ :............. ................... 343 Chapter 20. Air Duct Design.......'........................................;............:...................................... 351 Chapter 21. Industrial Exhaust Systems....;.................................... .................. ................... 371 Chapter 22. Fan Systems of Heating.................................... .................................................. 387 Chapter 23. Mechanical Warm Air Furnace Systems............................ ........................... 4p3 Chapter 24. Gravity Warm Air Furnace Systems............ :....... :....................... ................ 417 Chapter 25. Boilers.................:................ ...........;................................................... .'................ . 433 Chapter 26. Chimneys and Draft Calculations.... ............................................................... 451 Chapter 27. Fuels and Combustion.... ...................................................................................... 471 Chapter 28. Automatic Fuel Burning Equipment.............................................:................ 485 Chapter 29. Heat and Fuel Utilization...... ................... 509 Chapter 30. Radiators and Gravity Convectors.... ............... 521 Chapter 31. Steam Heating Systems...... :.................;........ .......................................;.......... 533 Chapter 32. Piping for Steam Heating Systems...................................................... ............ 557 Chapter 33. Hot Water Heating Systems and Piping............................................!.......... 587 Chapter 34. Pipe, Fittings, Welding--..................... 607 Chapter 35. Water Supply Piping and Water Heating..... :............... 629 Chapter 36. Insulation of Piping--............................................................................ ;............ 653 Chapter 37. District Heating....................:.........................;...... .......................... ;................... 671 Chapter 38. Radiant Heating........ ................. ........ _......... '...................................................... 689 Chapter 39. Electrical Heating........... ............................................................................... ...... 699 Chapter 40. Air Conditioning for Industrial Processes...................................................... 711 Chapter 41. Drying................................................^................... :................................................. 723 Chapter 42. Motors and Their Controls....... ............................................ :............................ 747 Chapter 43. Test Methods and Instruments........ ................................................ ............. 761 Chapter 44. Terminology....................... ;............................................................................. ;..... 771 Catalog Data Section............................................... ............................. _.......................793 Index to Advertisers........... ...................................... ................... ............. ;........................... . 795 Index to Modern Equipment...................................... :............................................................106I Roll of Membership......... ............,..... '................................. .......................... ............................1-64 'vii INDEX THE A. S. H. V. E. GUIDE 1936 14th Edition Technical Data Section Chapters 1-44 and Pages 1-792 Cross Reference to Subjects in Chapters 1 to 44 Alphabetically Listed A Abbreviations, 783 Absolute humidity, 7 Absorption, (see also Regain) as means of dehumidification, 182 closed, system, 51 of solar radiation by glass, 162 of sound, 329 * Acceleration, 771 Acclimatization, 62 ' Acoustics, acoustical, 325 effect of humidity on, 338 treatment, 330 Adiabatic saturation, 22, 182, 202, 771 Adjustable speed motor. 748 Adsorption, 771 as means of dehumidification, 182 systems alumina, 183 lithium chloride, 184 open liquid, 51 open solid, 52 silica gel, 183 Agitator dryers, 727 Air, adiabatic saturation of, 21 . amount per person, 77 ' atmospheric, 1 . changes of, indoors, 57, 138 cleaning devices, 200,. 771 A.S.H.V.E. code for, 300 ' ratings of, 300 requirements of, 299 types of, 301 ' composition of, 1, 57 Air (continued), , current dryer, 723 - density of. 6 distribution of, 343 auditorium, 347 . A.S.H.V.E. standards. 74. 76 for comfort, 76 ' downward, 348 effect of turning blades, 344 natural ventilation, 95 office, 346 railway air conditioning, 257, 348 residence, 345 stores, 346` in theaters, 347 with unit ventilators, 348 upward, 348 dry, 1, 4. 8, 70, 774 ducts, 351 (see Duds, Air) exfiltration, 131, 391, 509 filtration, 131, 140, 391, 509, 771 flow, 74, 76 -control, principles of, 95 . as cooling method, 179 diagrams, 351 formulae, 351 into a hood, 376 .natural, measurement of, 98 requirements; 96 tables, 351 through openings, 90, 95 friction of, in pipes. 353. 354 impurities in, 96. 287 size of, 299 ionization of, 80 - leakage. 131, 138 mixtures with water vapor, 10 moist, 70 Alphabetical Index to Technical Data Section Air (continued), Atmosphere, standard, 717 motion, 74, 76 Atmospheric steam heating system, 543. 569, 577 odors in, 57 Atmospheric water cooling apparatus, 204 optimum conditions, 67 - design of, 206 indoors in summer, 73 efficiency of, 207, 208, 212 . outside, introduced, Atomization, effect on temperature, 79 for humidifying, 213 ~* fan systems. 392 of oil. 495 through cracks, 138 Attic fans, 252 unit air conditioners, 242 Audiometer, 327 ' unit ventilators, 229 Automatic control, 269 (see also Controls) pollution, 287 Automatic fuel burning equipment, 485 abatement of, 291 Awnings, 408 effect on health, 288 .* primary, 473 , properties of, 2, 4, 74 quality, 74, 76 B quantity necessary, for combustion,-473, 483 . for ventilation, 74, 77, 530 Babcock's formula for steam flow, 557 recirculation of, 79 Baffles. 405, 772 fan systems. 388, 396 Bananas, 716 unit ventilators. 229 Barn ventilation, 99 saturated, 1, 5, 9, 779 Barometer, secondary, 473, 504 aneroid, 761 space conductances. 106 - mercurial, 761 speeds to convey material, 380 Baudelot, standard, 780 chamber, 203 summer, conditions, 73 heat absorber, 193 ' still. 64 Bends, expansion, 613 velocity, (see Velocity, Air) BET, British equivalent temperature, 691 vitiation, 57 Blast. 772 volume, 10 Blower, blowers, 309 (see also Pans) washer. 201, 772 (see also Washer, Air) standard test code for, 312 . cooling towers for, 204 Blow-through heating units, 389 operation of, 284 Body, human, surface area, 77 . saturation efficiency! 202 Boiler, boilers. 433, 772 , . weight of, 6 A.S.H.V.E. test codes, 438, 790 Air conditioning, 57, 74, 212, 771 (see also Air) A.S.M.E. construction code, 444 air change per occupant, 78 ' allowances, 648 A.S.H.V.E. standards, 74 . chemical factors, 57, 74 comfort chart, 68, 71 . baffles, 405, 772 capacity, 433 care during summer, 447 fundamentals of, 1 industrial, 711 cleaning, 447 connections, 444, 572 . apparatus for, 212 . conversion, 443, 501 ' automatic control, 281 exhaust systems, 371 design of, 436 domestic oil burners, 406, 500 of libraries, 720 . draft loss through, 462 plants, 212, 290 process conditioning, 711 efficiency of, 437, 439 for electric steam heating, 703 temperature differential in, 159 fittings. 444 unit, coolers, 235 . gas-fired, 435, 442, 502 . industries, requiring, 713 heat transfer rates, 437 * objective of, 1, 74, 83 heating surface, 437, 505, 772 physical factors, 57, 74 horsepower, 439, 772 - recirculation of air, 79, 277, 395, 410, 502 installation, 444, 446 -- standards, 57, 74 Algae formations, 209 Alternating current motor, 747 ' Alumina system of adsorption, 189 Aluminum foil, 125 Ammonia, 40, 206, 627 Anemometer, 765, 772 Anthracite, 471, 475 (see also Coal) Apartment houses, hot water supply to, 645 stokers suitable for, 490 Area of: ' chimneys, 457, 468 fittings, 617 grates. 400, 411, 424, 442 human body surface, 77 leader pipes, 419 pipe, 653 registers, 421 stacks, 421 1 wall surfaces, 104 ` A.S.H.V.E, Codes and Standards, 74,100,300,312," 529 ' A.S.M.E. boiler construction code, 445 Asbestos, 658 insulation, 448 . low pressure, construction code, 444 oil burners, 466, 500 operation, 446 output. 438 ' performance curves, 442 ratings of, 438 runouts, sizes, 574 scale in, 447 selection of, 400, 439, 442 settings, 436, 500 for mechanical stokers, 493 troubles with, 446 types of, 433, 703 warming-up allowance, 440, 442 water line, 445 Boiling point of water, 26 Booster, coils, 389 fans, 170. 430 Booths, spray, 378 Bourdon tube, 761 Boyle's law, 5 Brake horsepower, , fan. 205 heat equivalent of. 151 ' Ash, Branch connections, 535 cared for by stokers, 485 Breeching, draft loss through, 463 fly, 288 Brine. 193, 211 IX American Society of Heating and Ventilating Engineers Guide, 1936 British equivalent temperature, 691 British thermal unit, 772 Building, buildings, air velocities in, 357 classification for district heating, 683 construction, heat transmission of, 105, 107 district heating, 676 ' fuel requirements of, 509 . hot water supply to, 640, 643 intermittently cooled, 162 intermittently heated, 151, 413, 707 load factors, 518 materials, heat transmission of, 106 noise in, 327 saving of steam In, 677 8team consumption, 514 tall, infiltration in, 138 water supply to, 629 Burner, burners, automatic equipment, 485 coal, 485 conversion, 504, 506 - gas, 502 ` oil. 500 By-pass method. 170, 772 C Cabinets, (see Enclosures) dryers, 728 ` Calorie, 772 Calorific values, coal, 472 gas, 481 oil. 479 Can dryers, 727 Capacity motor, 750 . Capillary moisture, 732 . Carbon dioxide, 40, 206 . concentration in air, 76 . as corrosion agent, 626 . as an index of: combustion, 473 draft loss, 462 . odors, 57 measurement of, 767 Carbon monoxide, ., in air, 288 in garages, 100 poisoning, 289 produced by oil burners, 496 Carnot cycle, 44 Cattle, heat and moisture produced by, 99 Ceilings, heat transmission, 119 Central air conditioning systems, 169 automatic control of, 275, 283 design of, 171 . . location of apparatus, 172 ratings of, 176 spray type, 170 ~ Central fan heating systems, 387, 772 computations for. 395 ' connections, 579 design of, 391 electrical, 702 ' heating requirements of;.390 Charles* law, 7 . Chart, . of air densities, 6 ;. comfort, 68 . effective temperature, 64', 65, 66 . psychrometric, 64, 65, 66, 740, (back cover) Ringelmann, of smoke densities, 768 Chimney, chimneys, 451 action, 119 - areas of, 457, 461, 468 .. characteristics, 453 . . construction of, 465 effect. 90, 93, 119, 138. 549, 772 . for gas heating. 466 . .. . performance, 456 - sizes, 457, 461, 468 . , Venturi, 452 . Cinder, cinders, 288 . catching devices, 293 disposal of, 295 .' Circular equivalents of rectangular ducts, 360 Circulator, 503 City, maximum water main temperature, 180 Classrooms, (see Schools) Cleaners, air (see Air, Cleaning Devices) Clearance, window sash, 134 Coal, (see also Anthracile, Coke, Lignite) air speed for conveying, 380 analysis of, 471 bituminous. 477 calorific value, 472 classification of, 471 dust, disposal of, 295 . dustless, 478 ' pulverized, 478 . . semi-bituminous, 478 size of, 473 - Coal burning systems, . automatic control of, 278 automatic firing equipment. 485 boilers, 433 combustion rate, 404 . draft required for, 461 fuel requirements, calculation, 510 furnace requirements, 404. 411 - hand-fired, 479 stokers, 485 . ' . Codes, A.S.H.V.E. codes and standards, 790 for grinding, polishing, and buffing wheels, 374 for proportioning warm air heating plants, 502 for use of refrigerants, 171; 242 Coefficients of heat transmission, (see Heat Trans mission. Coefficients) Coefficient of performance, 44 . Coils, booster, 389 cooling, 241, 407 evaporator, 241 heating, 238, 389 hot water, 238 . . . pipe, 579 preheater, 389 radiator, 521 reheater, 389 steam, 238 ' tempering, 389 . . Coke, 472 combustion of, 478 . Cold, effects on human body, 60 Collectors, dust, 381 ,' Combined system, air conditioning equipment. 169 automatic control of, 276 central fan, 387 . . Combustion, 471 air required for, 473, 482 of different coals, 475 of gas, 481 of oil, 496 rates for heating boilers, 434 smokeless, 437 . ' ' . . with various stokers, 485 - ' Comfort, 62 chart, 68, 71, 76 . .. effective temperature, 63 . heating for, 689 .. . level, 525 `' line. 69. 71, 73, 773 for men working, 71 ., optimum air conditions for, 67, 71 . school children, 71 zone, 69, (see also Zone, Comfort) ' Compartment dryers, .728 . . .\ Compliance, of sound insulating materials. 336 Composition of water, 26 Compound wound motor, 747 . Compressed air, 213 Compressors, 37, 190 .. reversed refrigeration, 52, 706 . types of, 37, 190 ` Alphabetical Index to Technical Daja Section Condensation, on building surfaces, 151 meters, 681 prevention of, 151, 665 rate in radiators, 525 ' return pumps, 549 in steam heating systems, 533, 557 in winter, 71 Condenser, 37 design data, 194, 206 turbine, 204,208 ` - water temperatures, 207 ' Conditioning and drying, 717 (see also Air Condi tioning) Conductance, 104, 125, 773 of air spaces, 104, 106 of building materials, 107 of insulation, 107, 656 ' surface, 104 Conduction, 521, 773 Conductivity, 104, 125, 773 Conduit, 673 Connections, . for boilers, 444, 572, 574 . branch, 535 for central fan systems, 579 for chimneys, 461, 468 for convectors, 579 for direct heating systems, 676 for drains, 445 Hartford return, 574 for hot water systems, 604 for indirect heating units, 582 for pipe coils, 579 ' . for radiators, 577, 600 service, 676 constant speed motor, 748 Construction code for low pressure boilers, 444 Contact dryers, 723 Contours, velocity, 375 Control, controls, accessory automatic apparatus, 272, 773 of air conditioning equipment, 269, 281, 283 combined system, 276 split system 275 apparatus, 269 - automatic, 269, 272, 278. 283 connecting apparatus, 272 of cooling units, 281 . drying, 734 of electrical heating, 707 of fans, 319 - of electric motors, 747, 753 . manual, 93 . of mechanical warm air systems, 411 . of natural ventilation, 93 . of oil burning equipment, 279 rate of biochemical reactions, 715 . rate of chemical reaction, 715 rate of crystallization, 716 - . . of regain, 714 of relative humidity, 282 . of sound, 325 of steam heating systems, 548 . of temperature, 272, 499, 707 of vacuum pumps, 551 Convection, 84, 503, 689, 701, 773 Convectors, 521, 526, 773 A.S.H.V.E. code for, 529 ` connections for, 579 control of, 272 correction rating factors, 529 design of, 527 gravity, 521 heat emission by, 521, 528 heating capacity, 528 performance characteristics, 528 selection, -528 Conversion burners, 504 ' - ' Conversion equations, 785 Coolers, surface, 176 types of, 193 unit, 218 . Cooling, 20, 23 with central fan heating systems, 407 effect, 9 . . effective temperatures for, 75 . by electric refrigeration, 52, 706 equipment, design of, 206 evaporative, 169,179, 181, 202 of fluids, 207 of human body, 159 load, 157 with mechanical warm air systems, 415 methods, 169, 179, 407 ponds, 208 railway air conditioning, 259 . relative humidities for, 75 towers, 190, 195, 205, 208 units, thermostatic control, 281 water, 206 Copper pipe, 608 Corrosion, ' of boilers, 447 of industrial exhaust systems, 383 protective materials, 384 inhibitors, 627. of pipe, 626 tester, 627 Costs, of district heating service, 684 of electrical heating, 709 of railway fcir conditioning, 265 of unit conditioners, 252 Crack, window, 134 . Cyclone dust collector, 381 ..; Cylinder dryers, 727 D Dalton, law of partial pressures, 1 Damper, dampers, apparatus which operates, 271, 274, 277 control, 92 in duct systems, 409 .. types of, 409 , with unit ventilators; 230 Decibel, 325, 773 Definitions, 74 _ Degree-day, 773 base temperature for, 514 method of estimating fuel consumption, 511 records for cities, 512 . Dehumidification, 20, 201 effective temperatures for, 75 methods of. 169, 182, 240 by refrigeration, 182 1 relative humidities for, 75 * Dehumidifier, dehumidifiers, 182 alumina, 184 * . in central air conditioning systems, 170 in industrial air conditioning, 212 silica gel, 183 1 types of, 214 Density, 3, 773 of air, 6 of saturated vapor, 10 specific, 3 . of water, 30 . Design temperature, ' dry-bulb, 158 - wet-bulb, 158, 207 Dew point, 773 .' relation to relative humidity, 9 temperature, 2,282 .. Diameter, circular equivalents of rectangular ducts, 360 - Dichlorodifluoromethane, 37, 41, 191, 206 Diesel engine, 208 . Direct current motor, 747 . 1 Dirt pockets, 584 Disc fans, test code for, 312 Distribution of air, 343 (see also Air, Distribution) District heating, 671- . Diverter, back draft, 466 xi American Society of Heating and Ventilating Engineers Guide, 1936 Domestic oil burners, 494 Domestic supply, hot water, 500, 643, 705 water, 629 Doors, air leakage through, 134 coefficients of transmission of, 125 natural ventilation through, 92 Down-feed piping systems, 536, 537, 538, 541, 774 Downward system of air distribution, 348 Draft, 451 available, 454, 460 back, diverter, 466 dimensions, 467 calculations, 451 capacity, 453 equation, 460 gage. 762 head, 774 * intensity required, 460, 475 losses, 460 in chimneys, 463 . through fuel bed, 460 mechanical, 452 natural. 451 theoretical, 454 . towers, 210 Drain connections, 445 Draw-through heating units, 389 Drawing, symbols for, 787 * Dripping of steam pipes, 582 Drum dryers, 727 Dry-bulb temperature, (see Temperature, Dry-bulb) Dry return, 774 Dryers, agitator, 727 air current, 723 arrangement, 744 artificial air, 723 cabinet, 728 can, 727 compartment, 728 construction, 744 - contact, 723 cylinder, 727 design, 739 experimental technique, 744 drum, 727 electric induction, 729 loft, 728 . natural, 723 operating the, 737 operation, 724 pan, 727 '. room, 728 rotary, 728 spray, 728 ' tunnel, 729 types of, 727 Drying, 715, 723 (see alsoRegain) adiabatic temperature, 727 | - constant temperature, 727 . control operation, 734 ` circulation, 734 heat and humidity, 736 high temperature, 725 low temperature, 725 mechanism of, 729 methods of, 723 omissions in the cycle. 731 stages of moisture diffusion, 729 - constant rate period, 730 falling rate period, 730 sun, 723 ' time of, 737 materials, 738 vacuum, 726 ventilation phase, 742 . Duct, ducts, air, 351 . design of, 351, 356 equal friction method, 357, 359 velocity method, 357' for air distribution, 343 air velocities inf 380 Ducts, ducts (continued), circular equivalents, 360 . construction details, 368, 379 design of duct systems. 357, 366, 378, 408 humidity measurement in, 767 noise transmission through, 337 pressure loss in. 352 elbows. 352, 381 for recirculated air, 421 resistance, 381 sheet metal for, 368, 379 sizes of, 355, 359, 373 ' temperature loss in, 393, 419 temperature measurement in, 763 velocity measurement in, 764 Dust, 75, 287. 774 air speeds to convey, 380 catching devices, 293 - . collectors, 381 concentration in air, 299, 768 counter, 768 disposal of, 295 industrial exhaust systems, 371 measurement of, 768 Dynamic equilibrium Carrier's equation for, 2 EDR, equivalent direct radiation. 780 Effective temperature, (see Temperature, Effective) Elbow, elbows, design of, 408, 619 equivalents, 591 loss of pressure in, 352 resistance in, 381 sheet metal used in, 379 welding of, 621 Electric, electrical, central fan heating systems, 702 control, motor. 747 current, as corrosion agent,'626 - heat equivalents, 709 heating, 699 auxiliary, 707 cost of, 708 cost of insulation, 708 of hot water, 705 heating elements, 238, 699, 700 with unit heaters, 702 induction dryer, 729 , lamp bulbs, heat from, 151 .` motors, 747 Eliminator plates and baffles, 201, 205 . Emissivity, 692 Enclosures, .. concealed heaters, 527 convectors, 527 effect of, 525 unit air conditioners, 244 ' Engines, ' Diesel, 208 . internal combustion, 207' ' Enthalpy, 22, 775 . Entropy, 27, 775 . Equations, conversion, 785 Equilibrium, dynamic, 2 hygroscopic, 714 * moisture content, 734 Equipment room, design of, 333 Equivalent, equivalents, circular, 360 direct radiation, 150, 587, 780 - elbow, 591 ._ . evaporation, 439, 775 ./ heat, 785 of air infiltration, 140 of brake horsepower, 151 electrical, 709, 786 mechanical, 778 length of run, 561 square feet, 522 . Estimating fuel consumption, 509 xii Alphabetical Index to Technical Data Section Eupatheoscope, 695, 707, 770 Evaporation, 31, 32, 211, 212 equivalent. 439, 775 from human body, 59, 84 rate of. 31 from water pans, 526 Evaporative cooling, 169, 179, 181, 202 Evaporators, 38 Exfiltration, 131, 391, 509 Exhaust systems, 371 efficiency of, 383 flexible, 378 industrial, 372, 378 lateral, 377 . Expansion, of joints, 571, 673 of pipe, 571, 610, 673 in steam piping, 571 ' tanks, 602 Exposure factors, 150 F Fan, fans. 309 as accessory apparatus, 702 A.S.H.V.E. test code for, 312 attic, 252. 408 booster, equipment, 170, 430 brake horsepower, 205 control of, 319 for cooling. 408 designation of, 321 drives, arrangement of, 320 for drying, 318 " for dust collecting, 319 dynamic efficiency of, 311 efficiency of, 311 in electrical heaters, 702, 707 furnaces, 403, 415 for gas-fired furnaces, 502 for industrial exhaust systems, 383 . mechanical draft, 452 mechanical efficiency of, 311 motive power of, 321, 747 ' control of, 747 operating characteristics, 311 operating velocities, 317, 318 performance of, 309, 317 - quietness of, 226 ratings of, 316 selection of. 316. 319, 321, 383. 414 static efficiency of, 311 system characteristics, 315 systems of heating, 387 tip speeds, 317 total efficiency-of, 311 types of, 309, 313, 317, 430 in unit conditioners, 244 in warm air systems, 405, 414, 430 Fatigue, human, 61 Fiber saturation point, 732 Filter, filters. 295, 302 automatic, 303 doth, 382 design of, 302 dry air, 304 installation of, 305 resistance of, 407 for sound, 337 unit type, 302 - viscous type, 302 Fire walls, 379 . Fittings, 607 (see also Connections, Pipe) areas of, 615 ,* copper, 618 ` flanged, 619 lift, 545 ' screwed, 615 welding, 623, 624 - Flame, with oil burners, 495, 497 Flanges, welding neck, 623, 624 Floors, heat transmission-through, 119 Flowers, temperatures for greenhouses. 721 Fluid, fluids, cooling of, 207 formula for flow of, 351 meters, 680 ' Foodstuffs, regain of moisture of, 714 temperatures and humidities for processing, 718 Force, 775 Forge shops, heat given off in, 95 Formulae, conversion, 785 heat transmission, 105 Foundries, heat given off in, 95 Freezing, of cooling water, 211 insulation against, 663 ' Friction, of air in pipes, 354, 355 in chimneys, 456 coefficients, 355 heads in pipes. 590 in heating units, 390 losses in ducts, 353, 355, 359 -in water pipes, 637 Fuel, fuels, 471 (see also Anthracite, Coal, Coke, Gas, Lignite, Off) bed, draft loss through; 460 burning equipment, automatic, 485 , consumption, 509 ' * requirements, 510 ' degree-day method, 511 method of approximation, 510 utilization of, 509 Fumes, 287, 775 industrial exhaust systems, 371 toxirity of, 291 Fundamentals of heating and air conditioning, 1 Furnace, furnaces, 775 ` design of. 404, 411, 424. 436, 479 . door slot openings, 474 hand-fired, 479 performance curves of, 425 ratings of; 415 . types of. 403, 415, 502 volume. 775 ' for warm air systems, 403, 424 Fumacestat, 411 * G Gage, gages, - draft, 762 pressure. 761. 776 steam. 444 vacuum, 761 Galvanometer, 762 . Garage, garages, air flow necessary in, 96 A.S.H.V.E. ventilation code, 100 heaters for, 504 Gas, gases, calorific value, 151, 481 constant for dry air, 8 - in chimneys, 455 flue, analysis, 768 fuel, manufactured, 481 natural, 481 properties of, 482 .* scrubbers, 295 toxidty of, 291 Gas-fired appliances, 279, 501 ' accessory conditioning equipment, 252 automatic control of, 279, 501 , boilers, 435, 442. 502 selection factors, 505 ' carbon monoxide produced by, 506 chimneys for, 466 . classification, 501 control of. 502, 504 conversion burners, 504, 506 furnace requirements for, 404, 411 Xlll American Society of Heating and Ventilating Engineers Guide, 1936 Gas-fired appliances (continued), installation, 506 rate of gas consumption, 505, 517 ratings of. 505 types of space heaters, 503 used with unit heaters, 227 warm air furnaces, 502 Gaskets, 620 Glass, heat transmitted through, 125, 164 solar radiation through, 163 window, area, 104 Glossary of terms, 771 Grates, 776 areas of, 400, 411, 424, 442, 776 of furnaces, 400, 411. 424, 442 of stokers. 485 Gravity, convectors, 521 heat emission of, 521 gravity-indirect heating systems, 530 specific, 2 steam heating systems, 533 one-pipe air-vent, 533, 536, 565. 577 two-pipe air-vent, 537, 566, 577 warm air heating systems, design of, 417 Greenhouses, temperatures for, 721 Grille, grilles, 776 (see also Registers) - anemometer readings through, 765 for concealed heaters, 528 of roof ventilators, 92 for warm air systems, 409, 421 . H Hartford return connection, 536, 574 Health, effect of air pollution on, 288 Heat, 776 absorbed by building structure, 151 air infiltration equivalent of, 140 capacity, 85, 162, 776 of leader pipes, 419 conduction, 773 consumption, 509 . content, of air and water vapor, 10 of dry air, 21 of saturated water vapor, 22 convection, 773 conversion equations, 785 demand, factors governing, 143 effects on human body, 59 electrical equivalents of, 709. 786 emission, of convectors, 521, 528 by radiation, 692 of radiators, 521, 528 equivalent, equivalents, 785 of air infiltration. 140 of brake horsepower, 150 electrical, 709, 786 exchanger, 204, 206 shell and tube, 193 flow meter, 104, 769 gain, from fixtures and machinery, 165 from outside air, 165 to be removed, 175 nfiltration equivalent of, 140 latent, 30 loss, 82 of the liquid, 27. 777 loss, from bare pipe, 653 computation of, 103, 152, 692, 707 determination of, 143, 150, 509, 689 effect of insulation on, 667 . by evaporation, 32 ' from human body, 82, 689, 691 . by infiltration, 140, 509 . by intermittently heated buildings, 413 latent, 82 from piping of gas-fired furnaces, 504 Heat (continued), by radiation. 67, 689 sensible, 82, 691 to unheated rooms, 128 maximum probable demand. 143 mechanical equivalent of, 778 of the liquid, 27. 777 produced by cattle, 99 produced by human body, 58 pump, 52, 706 radiant, 724 radiation, 779 regulation in man, 58, 62 requirements, 510 sensible, 179, 776 of air, 10 ' loss. 82, 691 of water, 30 solar, 160 sources of, 689, 703 other than heating plant, 150, 187 specific, 30 . total, 21. 282, 781 of saturated steam, 27 transmission, 103, 689 through air spaces, 106 through building materials, 106 calculations, 103 . coefficients, 103, 126 of ceilings, 119 - combined, 127 . - of doors, 125 of floors, 119 of insulation, 107 of roofs, 122 of skylights, 125 of walls, 112 of windows, 125, 164 convection equation, 689 definition of terms used, 104 effects of solar radiation on, 169 formulae, 105 ' through glass, 125, 164 measurement of, 769 in surface coolers, 177 by surfaces not exposed to the sun, 159 symbols used in formulae, 104 tables, 103, 107 time lag, 162 utilization, 509 Heaters, for domestic hot water, 645 electric, 700 capacity of, 709 radiant, 503, 701 space, 503 unit, 218, 219, 702 wall, 503 Heating (see also Heat) district, 292, 671 effect of radiators, 524 '. electrical, 699 elements, electric, 700 fundamentals of, 1 load, 143 medium, 776 radiant, 689, 700 railway air conditioning, 259 ' by reversed refrigeration, 52, 706 surface, 437, 777 square foot of, 780 '. systems, district, 671 electrical, 699 . fan, 387 ' gravity warm air furnace, 417 . hot water, 587 mechanical warm air furnace, 403 radiant, 689 steam, 533 units, blow-through, 389 - central fan, 389, 702 ' draw-through, 389 water, 629 Henry and Dalton, law of, 626 XIV Alphabetical Index to Technical Data Section Hoods, a rial velocity formula, 375 canopy, 377 for chemical laboratories, 378 design of, 375 for exhaust systems, 371 of furnaces, 405 open. 377 suction pressures at, 374 Horsepower, 777 boiler, 439, 457. 772 ian, heat equivalent of, 150 Hot box, 104, 769 Hot plate. 769 Hot water heating systems, 587, 777 electric, 704 forced circulation, 589 gravity circulation, 597, 601. installation of, 603 mechanical circulation, 601 Hot water piping, 587 Hotels, stokers suitable for, 490 temperatures of in winter, 144 water supply, 629 Humidification, 20, 201 atomization for, 213 effective temperatures for, 75 methods of, 239 relative humidities for, 75 for residences, 414, 526 systems of, 212 with water pans, 526 in winter, 171, 526 Humidifier, huraidifiers,~253 . atomizing, 213 with fan systems,- 398 - high-duty, 213 spray, 214 . types of, 213 Humidistat, 271, 411, 777 Humidity, 7. 75, 777 absolute, 7, 771 control, 269 railway air conditioning, 263 effect of on acoustics, 338 , for industrial processing, 718 " measurement of, 766 relative, 8. 75. 779 (see also Relative Humidity) A.S.H.V.E. standards, 75 in comfort zone, 70 effect on moisture regain* 713 relation to dew point, 9 specific, 8, 777 . Hygrodeik, 777 Hygroscopic materials, 712 moisture content, 711, 732 processing of, 717 regain, 711, 712 ` Hygrostat, 271, 777 I Ice, in air conditioning, 194, 241, 407, 415 Inch of water, 777 induction motor, 749, 750, 751 Industrial, air conditioning, 711 apparatus for, 212 automatic control of, 281 . classification of problems, 714 ~ air pollution, 289 cooling systems. 182 drying, 318, 713 electrical heating systems, 706 exhaust systems, 371 heat sources, 150 plants, 711 . processing of hygroscopic materials, 713 temperatures and humidities for, 718 ^ unit heaters, 228 Infants, premature, 69, 70 Infiltration, 771 . average, 138 fuel utilization, 509 heat equivalent, 140 . through shingles, 133 through walls, 132 through windows, 134 Inlet opening, long throw, 343 short throw, 344 - Institutions, water supply to, 631 Instruments, 761 Insulation, 777 asbestos type, corrugated, 658, 659 laminated, 660, 661 . of boilers, 448 bright metal foil, 125 . building, 708 characteristics of, 107, 657 effect on heat loss, 667 with electrical beating, 699 heat transmission through, 107, 657 for low temperatures, 656 of machinery, 333 - magnesia type, 657 of piping, 653 to prevent condensation, 151, 153, 665 to prevent freezing, 663 reflective type, 125 rock wool type, 662 of sound, 330 . tables, 107, 657 thickness needed, 666 types of, 108 underground, 667 of vibration, 334 Internal combustion engines, 207 Ionization of air, 80 . Isobaric, 777 Isothermal, 7, 777 Internal moisture gradient, 734 J-K Joints, expansion. 571, 673 Kata thermometer, 76,.766 'L Latent heat, 30, 777 . loss, 82 . of water vapor, 10 Lead poisoning, 290 ' Leader pipes, 417 heat carrying capacity of, 419 size of, 419, 429 Leakage of air, 131 (see also Infiltration) Length of run, equivalent, 561 Libraries, air conditioning of, 720 Lignite, 472 . Lithium chloride system of adsorption, 184 Liquid, heat of the, 27, 777 Load, cooling, 85, 157 design, 438, 775 ' heating, 143 . hot water supply, 441 maximum, 440 radiation, 440 Loft dryers, 728 Loudness, 325 Louver fences, 209 M Machinery, . as heat source, 150, 166 sound insulation of, 333, 335 XV American Society of Heating and Ventilating Engineers Guide, 1936 Magnesia insulation, 657 Manometer, 764, 777 Masonry materials, heat transmission through, 107 Mass, 778 Mb. 587, 778 Mbh, 587. 778 Mean radiant temperature, 689, 692 Mechanical, draft towers, 210 equivalent of heat, 778 refrigeration, 37 ventilation, 79 warm air furnace systems, 403 Metabolism, 59, 81 Meters, choice of, 680 condensation, 681 fluid, 680 Nicholls heat flow, 769 steam flow, 682 types of, 680 water, disc, 635 Methyl chloride, 42, 206 Metric units, 787 Micron, 299, 778 Mixture, air and water vapor, 10 Moisture, 665 content, of air. 77, 179, 212, 711 as index of air distribution, 76 calculations, 737 equilibrium, 734 of hygroscopic materials. 712, 729 internal, gradient, 734 loss by human body, 82, 84 from outside air. 172 .' produced by cattle. 99 regain, 711 Mol, 778 Monitor openings, 92 Monofluorotrichloromethane, 43 Motive power, 747 Motors, electric, 747 adjustable speed, 748 adjustable varying speed, 748 alternating current, 747 capacitor type, 750 ` classification of, 752 compound wound, 747 constant speed, 748 control equipment for, 753 automatic, 754 manual, 753 multispeed, 756 pilot, 754 single phase, 758 slip ring, 757 direct current, 747 control of, 755 as heat source, 150 induction, . automatic start, 751 repulsion start, 749 slip ring wound rotor, .751 squirrel cage, 750 polyphase, 750 selection of, 383 series wound, 747 shunt wound, 747 single phase, 749 special applications, 753 split phase, 750 synchronous, 751 varying speed, 751 MRT, mean radiant temperature, 689, 692 N Noise (continued), control of, 329 . through ducts, 337 with warm air systems, 406 level, acceptable, 329 of compressors, 191 of fans, 317 of unit heaters, 226 of various apparatus, 328 measurement of, 326 Nozzle, 201 air spray, 173 oil atomizer, 495 water spray, 213 O Odors, 76 of human origin, 57 concentration, 79 removed by outside air, 79 ou, oils, atomization of, 451 burner, burners, accessory conditioning apparatus, 251 air for combustion, 496 air supply for, 495, 497 automatic, 500 boilers. 435, 437, 499 carbon monoxide produced by, 496 for commercial use, 500 control of. 278, 499 design considerations, 498 for domestic hot water supply, 500 for domestic use, classification, 494 efficiency of combustion, 498 flame with, 495 furnace requirements, 404, 411, 496 ignition, 495 installation, 497 ` oil consumption, 498, 509, 516 operation, 495 Orsat test. 498 specifications, 479 calorific value of, 480 ' classifications. 479 as corrosion inhibitor, 627 cost of, 481 heated electrically, 706 Ignition of, 480 preheating, 500 specifications, 479 One-pipe steam beating systems, gravity air-vent, 533, 537, 565, 577 down-feed, 537 up-feed, 534 vapor, 538 Openings, air inlet, 92, 343 . characteristics, 343 monitor, 92 for natural ventilation, location of, 95 resistance offered to flow,'96 size of, 89 * types of, 90 Orifice, orifices, ' friction heads, 596 steam heating systems, 547, 559, 569', 577 Orsat test apparatus, 498, 768 ' Outlets (see also Registers, Grilles) design and location of, 173 Oxygen, 626 Ozone, 79 i Natural draft towers, 210 Natural dryers, 723 Natural ventilation, 79, 89 Nicholls heat flow meter, 769 Noise (see also Sound) in buildings, 327 P Paint, ` effect on radiators,' 523 . spray booths, 378 temperatures and humidities for processing, 718 XVI Alphabetical Index to Technical Data Section Pan dryers, 727 Partial pressures, Dalton's law of, 1 Perspiration, 59, 79, 83, 85 Petterson-Palmquist apparatus, 767 Phon, 326 Pipe, piping, 607 bare, heat loss from, 653 bends. 571, 613 capacities (see Pipe, Sizes) coil radiators, 521 conduit, 673 connections, 572, 676 (see also Connections) copper, 608 corrosion of, 626 dimensions of, 608, 653 (see also Pipe, Sizes) down-feed systems, 536, 537, 538, 541 expansion of, 571, 610, 673 fittings, 586 (see also Connections, Fittings) for water supply, 634 welding fittings, 622, 653 flanges, 623, 653 flexibility of, 610 friction, of air in, 353 heads in, 591 gaskets, 620 ' hangers. 614 heat loss from, 505, 653 for hot water heating systems, 587, 603 insulation of, 653 joints, 571, 673 leader, 419 . ' radiators, 521 scale in, 626 sizes, for boiler runouts, 574, 672 for central fan systems, 579 for convector connections, 579 dimensions, 608, 610 ' for district heating, 672 for domestic hot water, 640 effects of variation of, 595 elbow equivalents, 591 equivalent length of run, 561 friction head, 592 . of orifices in unions, 596 for Hartford return connection, 574 for hot water heating systems, 588 forced circulation systems. 590 * gravity circulation systems, 597 for indirect heating units, 582 for pipe coil connections, 579 for radiator connections, 577 return, capacity of, 564 steam, 558, 562, 563 underground, 671 41 tables, 563. 610 tees, 617 " for underground steam, 671 ' for water supply, 633 weights, 608 steam, capacity of, 559 for steam heating systems, 533, 557 supports, 614 sweating, 665 systems, down-feed, 536, 537, 538, 541 systems, up-feed, 534, 537, 539, 542 tax, 441 tees, dimensions of, 617 ' threads, 614, 618 tunnels, 675 types of, 607 underground, ^ insulation of, 667 ,, steam, 671 for unit heaters, 226 up-feed systems, 534, 537, 539, 542 valves, 622 water supply, 629 weights of, 608 welding, 621 ' Pitot tube, 764 (Plastering materials, heat'transmission through, 109 'Plenum, chamber, 778 systems, automatic control of, 275 Plumbing fixtures, 629 Pollution of air, 287 Polyphase motors, 750 Ponds, cooling, 208 Pool, swimming, 650 Potassium permanganate, 209 Potentiometer, 763, 778 . , Power, 778 conversion equations, 785 electric, 708 . supply, . railway air conditioning, 264 Precipitators, dust, 294 Pressure, pressures, absolute, 771 air, in heating unit, 390 measurement of, 764 * atmospheric, 761, 772 for atomization, 202 barometric, 455, 761 basic, 3 . conversion equations, 786 drop, formula for, 672 dynamic, 774' gage, 761, 776 loss through ducts, 351 ' measurement of, 761 partial, Dalton's law of, 1 refrigerating plant, 206 of saturated vapor, 10 static, 400, 780 steam, in district heating, 672 . drop. 536, 558, 563 initial, 558 in orifice systems, 547 - ' saturated, 27 in sub-atmospheric systems, 546 total, 781 ' vapor, 31, 782 velocity, 782 , water, 26, 633 ' * * i . , " Processing, 711 cooling systems, 182 industrial, temperatures andjhumidities for, 718 of textiles, 713 unit heaters, 228 Propeller fans, test codeIfor/312- Psychrometer, 779 sling, 766 - Psychrometric, chart, 64, 65, 66 (back cover) for dryer, 740 explanation, 24 tests, 63 ' Pump, pumps, circulating, 601 condensation return, 549 heat, 52, 706 vacuum, 550 ratings of, 550 Pyrheliometer, 160 . Pyrometer, 763, 779 mercurial, 763 optical, 763 radiation, 763 thermo-electric, 763 ^ Q> Quality, of air. 76, 80 - A.S.H.V.E. ventilation standards, 74 impaired by recirculation, 80 xvu American Society of Heating and Ventilating Engineers Guide, 1936 Quantity, of air, A.S.H.V.E. ventilation standards, 74 blow by wind, 89 measurement of, 764 necessary for ventilation, 77, 79, 95, 173 of cooling water, 206 R Radiant heaters, 503 , Radiant heating, 689, 724 Radiation, 779 by black body, 692 direct, control of, 272 equivalent direct, 150, 587. 780 heat loss by, 67, 689 by human body, 62, 67, 84, 689 load, 440 with oil burners, 498 by radiators, 521 solar, 160 curative value of, 81 effect on heat transmission, 160 occlusion of, 289 through glass, 163 through walls, 162 ultra-violet, 80 Radiator, radiators, 521, 779 A.S.H.V.E. code for. 529 column, 773 condensation rate in, 525 connections, 577, 600 control of, 272 correction rating factors, 529 effect of superheated steam, 523 enclosed, 525 gas-fired, 503 heat emission of, 521, 528 heating capacity of, 528 heating effect of, 524 for hot water systems, 598 output of, 522 ' paint, effect of, 523 panel, 778 pipe coil, 521 . ratings of, 522 selection, 528 shields. 496 types of, 521 wall, output, 522 warm air, 504 Railway air conditioning, air distribution, 257, 348 cooling, 259 calculation of, load, 260 capacity, 260 internal combustion engine, 259 mechanical compressor, 259 methylene chloride, 259 costs, 265 heating, 259 humidity control, 263 power supply, 264 tractive resistance, 264 temperature control, 263 ventilation, 257 Rain, as dust catcher, 296 ` Rates, district heating, 684 Ratings, of air cleaning devices, 300 of boilers, 438, 505 for central fan conditioning, 176 of concealed beaters, 528 of fans, 316 of furnaces, 415 of gas-fired appliances, 505 of noises, 328 of pressure reducing valves, 569 of radiators, 522 for surface coolers, 176 for unit air conditioners, 250 of unit coolers, 237 Ratings (continued), . of unit heaters, 222 of unit ventilators, 233 * of vacuum pumps, 550 Receivers, alternating, 555 Refrigerants, 37, 190, 779 codes for use of, 171, 242 comparison of, 44 ' tables of, 40, 41, 42, 43 types of, 192 Refrigerating, capacity, 43, 187 Refrigerating effect, 43 Refrigerating plant, 204, 206 compressor, 208 operating methods, 188 . size of, 188 . steam jet system, 189, 208 Refrigeration, characteristics, 49 curves, 48, 49 coefficient of performance, 44 camot cycle, 44 compression ratio, 46 dehumidification by, 182 efficiency, cycle, 44 ejector, 48 . mechanical, 46 practical cycle, 44 . losses, 45 reverse cycle, 52, 706 limiting factors, 53 systems, closed absorption, 51 . mechanical, 37 open adsorption, liquid, 51 solid, 52 . steam ejector, 46 various types, 37 theoretical mechanical cycle, 38 - theoretical work per pound, 39 ton day of, 781 ton of, 43. 187, 781 unit of, 43, 187 Regain, control of, 714 of hygroscopic materials, 712 Registers, 779 (see also Grilles) with gas-fired furnaces, 503 with mechanical warm air furnace systems, 409 sizes, 421, 429 and stacks, 93 Reheaters, 175 Relative humidity, 8, 779 apparatus sensitive to, 271 A.S.H.V.E. standards, 74 for banana ripening, 716 ' in comfort zone, 70, 73 relation of dew point to, 9 control of, 282 . ' effect on sound, 338 in industrial plants, 711 of libraries, 720 for processing, 718 in public buildings, 73 in residences, 526 -, ' from water pans, 526 ' Research residence, 407, 427 Residences, ' air distribution in, 346 - ' humidification of, 414, 526 , oil burners for, 494 conversion burners, 504 -. * ' stokers for, 488 - Resistance, . of bright metallic surfaces, 125 of building materials, 107, 665 in ducts, 381 of exhaust systems, 382 of filters, 407 of insulators, 107, 665 of sound-insulating materials, 334, 336 thermal, 780 Resistor, 700, 703 ' '^y Alphabetical Index to Technical Data Section Restaurants, ' tobacco smoke in, 77 water supply to, 651 Return, dry, 774 pipe, capacity, 564 wet, 782 Reverse cycle of refrigeration, 52, 706 Ringelmann chart, 768 Rock wool insulation, 662 Roof, roofs, coefficients of transmission of. 122 conductivities of, 109 solar radiation on, .160, 161 ventilator, 92, 779 Room dryers, 728 S Salts in cooling water, 205 Saturation, fiber point, 732 Scale, in boilers, 447 centigrade, 762 on equipment, 205 Fahrenheit, 762 - in pipe, 626 . Reaumur, 762 School, schools, air distribution in, 348 air flow necessary in, 96 optimum air conditions, 71 stokers suitable for, 492 temperature of, in winter, 144 ventilation in, 71 " . Scrubbers, 295, 301 air, 201 Sensible heat, 179 of air, 10 loss, 82 of water, 30 series wound motor, 747 Settling chamber, 294 ' Sheet metal, for ducts, 368, 379 Shingles, air leakage through, 133 shunt wound motor, 747 Silica gel, regain of moisture of, 712 , system of adsorption, 183 ' - Silicosis, 290 single phase motor, 749 Sizes of pipe (see Pipe, Sizes) Skylights. 92. 125 Sling psychrometer, 766 Smoke, 287, 779 abatement of, 291 measurement of, 768 ' recorders, 768 tobacco, 77 Solar heat, 160 Sound, 325 absorption coefficients, 329 . control, 325 effect on duct design, 367 effect on humidity on, 338 effect of temperature on, 338 insulation of, 330 intensity, 325 measurement of, 326 in steam heating systems, 560 Specific density, 3 Specific gravity, 2, 779 of fuel gas. 454 Specific heat, 3, 779 mean, of water vapor, 3 of water, 30 Specific humidity, 8 Specific volume, 3, 779 of saturated steam. 26 Split phase motor, 750 . Split system, 780 - air conditioning equipment, 231 automatic control of, 275 central fan, 387 Spray, booths for painting, 378 cooling, ponds. 208, 210 efficiency of, 209 . towers. 209, 210 distribution of, 213 dryers, 728 generation of, 213 humidifiers. 214 type of central station system, 170 . water coolers, 193 Square foot of heating surface, 780 Stack, stacks, 93, 417 . effect, 90 height, 780 . size of, 95, 420, 429 system with registers, 93 wall, 420 Stairways, 139 Standards. air conditioning, 57, 74 A.S.H.V.E. codes and standards, 74 for pipe, 609 for ventilating industrial plants, 290 for welding, 621 Steam, 206, 780 coils, 238 condensing rates, 524 _ consumption for buildings. 514 - flow, Babcock's formula, 557 heat content of. 22 a9 heat source, 703 ' heating systems, 533, 780 air-vent, 533, 537, 565, 566 atmospheric, 543, 569, 577 classification, 533 ' condensation return pumps, 549 _ connections (see Connections, Fittings) corrosion of, 626 . design of, 543, 557 dirt pockets, 584 . district heating, 671 dripping of, 584 electric, 703. equivalent length of run, 561 gravity systems, 533 one-pipe, 533, 537, 565, 577 ' two-pipe, 537, 566, 577 . with high-pressure steam, 569 mechanical, 533 orifice, 547, 559, 569, 577 pipe, 557 (see also Pipe) capacity, 559, 562 sizes.. 558, 562 ' pressure drop in, 536, 546 sub-atmospheric, 545, 552, 559, 569, 577 types of, 533 vacuum, 543, 550, 553, 568 vapor, 559, 577 < . one-pipe, 538 two-pipe, 539, 541, 567 . ' water hammer in, 560 zone control, 548 high pressure, 569 jet apparatus, 189 . meters for, 680 pressure, 569 '. ' properties of, 22 ' requirements of buildings, 510, 683 * saturated, properties of, 27 savings in use of, 677 tables, 7, 22, 27 . trap, 780 . underground, 671 in unit heaters, 221 Stokers, apartment house, 490 automatic control of, 278, 411 1 commercial, 492 design of, 485 v economy of. 485 household, 488 .- mechanical, 485 *, operating requirements, 4S9 XIX American Society of Heating and Ventilating Engineers Guide, 1936 Stokers (continued), overfeed inclined grate, 486 heating boilers, setting heights, 493 types of, 436. 485 underfeed rear cleaning, 487 underfeed side cleaning, 486 Storage, of hot water, 644, 648 temperatures and humidities for, 718 Storm sash, 134 Sub-atmospheric systems, 545, 552, 559, 569, 577 Suction, static, in exhaust systems, 373 Summer, care of heating boilers, 447 ** comfort zone, 68, 69, 73 conditioning, apparatus for, 169 desirable indoor conditions in, 73, 75 temperatures, 158 wind velocities and directions, 158 Sun, - diurnal movement of, 160 drying, 723 effect, 85 . effect on heating requirements, 548 factor of cooling load, 164 Surface, cooling, 170 equipment^ 176 air conditioning, 170 ratings. 176 extended. gravity-indirect heating systems, 530 heating, 775, 777 square foot of, 780 radiant heating, 693 Swimming pool, 650 Symbols, for drawings, 787 for heat transmission formulae, 104 Synchronous motor, 751 Synthetic air chart, 780 T Tank, tanks, for domestic water supply, 636 expansion, 602 . flush, 636 Tees, dimensions of. 617 Temperature, absolute, 771 adiabatic, drying, 727 of air leaving inlets, 173, 392 . - ammonia, 206 apparatus sensitive to, 269, 762 atmospheric, 455 for bananas, 716 of barns, 99 base, for degree-day, 514 basic, 3 body. 58, 60. 690 changes, effect on human beings, 61 of chimney gases, 455 in cities, 148, 158, 512 of city water main, maximum, 180 commonly specified, 3 constant, drying, 727 control of, 269, 272, 499, 707 railway air conditioning, 263 of cooling water, 206 dew-point, 2, 282, 774 difference, between floor and ceiling, 146, 524 desired, determination of, 95 . in stacks and leaders, 93, 419 dry-bulb, 1, 2, 76. 774 as index of air distribution, 76 maximum design, 158 specified in winter, 144 Temperature {continued), effect on moisture regain, 713 effect on sound, 338 - effective, 64, 75, 145, 179, 774 A.S.H.V.E. standards, 74 chart, 64, 65. 66 for maximum comfort, 69, 691 optimum, 69 scale. 63, 75 . final. 390 of gas flame, 482 for greenhouses, 721 in industrial plants, 711 in industrial processing. 717, 718 inside, 73, 145, 392 surfaces, 692 low, insulation for, 656 of mean interior surface, 692 mean radiant. 689, 692 measurement of. 99. 269, 762 in occupied space, 73, 77 outside. 146, 158 radiation-convection, 695 range of cooling equipment. 207 records of cities, 148, 159 at registers, 419, 424, 531 room, 9. 511. 763 ' sensations, 62 surface, of man, 690 mean interior, 692 systems for control of, 272, 499, 707 thermo-equivalent conditions, 63 value used in calculations, 136, 392 water main, maximum, 180 wet-bulb, 2, 21, 767, 782 average, 207 design, 158, 207 as index of air distribution, 76 maximum, 207 Terminology, 771 Test methods, 761 Textile, textiles. fibres, regain of moisture, 711 weaving of, 715 temperatures and humidities for processing, 718 testing, standard atmosphere for, 715 . Theaters, air distribution in, 348 cooling in, 348 heat sources in, 83 . temperatures of. 73, 144 Therm. 780 Thermocouples, 762 Thermodynamics, 780 of air conditioning, 1 laws of, 777 Thermo-equivalent conditions, 63 Thermometer, duct, 763 globfe, 695 Kata, 766 mercurial, 762 recording, 764 .. resistance, 763 - Thermopile, 763 Thermostat, thermostats, 781 differential. 9,269 with gas-fired furnaces, 502 location of, 273, 278, 411 . with oil burners, 499 with radiant heaters, 707 types of, 93,230,269 . s ' . ' ` Tobacco smoke, 77 ' Ton of refrigeration, 43, 187, 781 '. Ton-day of refrigeration, 781 Towers, cooling, 190,195. 205, 208 atmospheric, 210 . mechanical draft, 210 natural draft, 210 spray, 209 XX Alphabetical Index to Technical Data Section Traps, dust catchers, 294 return, automatic, 555 with steam heating systems, 540, 552 types of, 552 Tube. Bourdon, 761 Pitot, 764 shell and tube heat exchanger, 193 Tubing, copper or brass, 618 Tuning fork, 327 Tunnel dryers, 729 Tunnels, for steam pipe, 675 Turbines, with unit heaters, 228 Two-pipe steam heating systems, gravity air-vent, 537, 566, 577 down-feed, 538 up-feed, 537 vapor, 539, 567 down-feed, 541 U Ultra-violet light, 80, 289 Underwriters' loop, 536, 574 Unit air conditioners, 217, 218, 237, 781 accessory apparatus, 218 advantages, 218 air distribution, 243 classification, 217, 238 cooling, 240 construction of apparatus, 244 costs, 252 design of. 244 filtering, 242 functions pf, 217 heating, 238 humidifying, 239 location of, 243 ratings of, 250 required capacity of, 251 types of, 238 uses of, 238 ventilation, 242 . Unit conditioning systems, 217 {see Unit Air Con ditioners) Unit coolers, 218. 235, 781 design of, 235 ratings of, 237 Unit equipment. 218 advantages. 218 controls. 254 miscellaneous, 252 . Unit heaters, 217, 218. 781 air temperatures, 222 blow-through type, capacity of, 224 ` boiler capacity, 226 control of, 273 design of, 219 - direction of discharge, 223 draw-through type, capacity of, 225 electric. 227, 702 estimating heat losses, 221 heating medium, 221 ` industrial uses, 228 output of, 222 piping connections, 226 quietness, 226 ratings of, 222 types of, 219, 702 used in industry, 227 Unit ventilators, 217, 218. 228 y capacity of, 232 control of, 274 design of, 228 . ratings of. 233 *. vents, 232 Unwin pressure drop formula, 672 A Up-feed piping systems, 534, 537, 539, 542, 782 Upward system of air distribution, 348 V Vacuum drying, 726 Vacuum pumps, 550 Vacuum refrigeration, 46, 189 Vacuum system of steam heating, 543, 550, 553, 568, 782 Valve, valves, 622 apparatus which operates, 271 on boilers, 445, 572 control, with steam heating systems, 571, 622 * with high pressure steam, 569 operator, 271 pressure-reducing, 570 ratings of, 569 for radiators, 535, 539 roughing-in dimensions, 625 sub-atmospheric system, 545 on traps, 553 types of, 622 for water supply, 634 Vapor, 782 mixture with air, 10 pressure, 10 . -steam heating systems, 538. 782 . water, 3, 5, 9, 10, 22 . weight of saturated, 10 . Varying speed motor, 751 Vegetables, temperatures for greenhouses, 721 Velocity, 782 air, A.S.H.V.E. ventilation standards, 74 in ducts of buildings, 357, 367 in exhaust systems, 373, 380 through heating units, 390 measurement of, 764 through mechanical draft towers, 211 through openings, 98 sound effect of, 338, 367 for ventilation, 76 chimney gas, 457 draft loss. 463 . contours, 375 . ' in ducts, 764 of fans, 319 head, of fluids, 351 steam, through an orifice, 569 in underground pipes, 671 f . water, in pipes, 592 wind, choosing, 136 measurement of, 98 on natural draft equipment, 210 in natural ventilation, 89 " ^ Vent, vents, in gas-fired steam or vapor systems. 506 on traps, 553 ' in unit ventilators, 232 ' Ventilation, 57, 782 {see also Air, Distribution) A.S.H.V.E. standards, 74,790 of barns, 99 drying phase, 742 of garages, 100 mechanical, 79 with roof ventilators, 93 . . . natural, 77, 138 advantages of, 79 air changes per hour, 138 control of, 93 disadvantages of, 79 general rules for, 97 heat to be removed by, 95 requirements for, 79 openings, doors, 91 formula to determine size of, 89 location of, 95 American Society of Heating and Ventilating Engineers Guide, 1936 Ventilation (continued), . Water (continued), , openings line, skylights, 91 in boilers, 445, 446, 533 types of, 90 in water supply systems, 636 windows, 91 make-up, 211 for public buildings. 359 meters, disc, 635 purpose of, 95 quantity of air necessary for, 77, 531 . pans, for humidification, 526 pressures, 26 Chapter 1 railway air conditioning, 257 properties of, 26, 30 by registers, 93 removal of free, 732 for schools, 72, 348 . replacement of, 211 by stacks, 93 . standards, 74, 790 supply piping, 629 temperature, maximum main, 180 FUNDAMENTALS OF HEATING AND for theaters, 348 Ventilator, ventilators, resistance of, 92 thermal properties of, 30 vapor, 5, 9, 10 given off in combustion of gas, 481 AIR CONDITIONING roof. 92, 779 heat content, 10, 22 ` unit, 218 (see also Unit Ventilators) mean specific heat of,- 3 . . Venturi chimney, 452 weight of saturated, 10 . Dalton's Late, Dry- and Wet-Bulb Temperatures, Properties of Vibration, insulation of, 333 Vitiation of air, 57 Volume, of air and saturated vapor, 10 conversion equations, 785 furnace, 779 specific, 3 of saturated steam, 27 of water, 30 ' Weather Bureau records, temperature, 148, 158 wind. 148, 158 Weatherstripping, 136 Weight, of air, 6 conversion equations, 785 of steam, 27 of vapor, 10 of water, 30 Welding, 607, 621 neck flanges, 623, 624 . . . . . Air, Humidity, Relative Humidity, Specific Humidity, Relation of Dew Point to Relative Humidity, Adiabatic Saturation of Air, Total Heat and Heat Content, Enthalpy, Psychrometric Chart, Properties of Steam, Properties of Water, Rate of Evaporation At IR conditioning has for its objective the supplying and maintaining, in a room or other enclosure, of an atmosphere having a composition, temperature, humidity, and motion which will produce desired effects W Wet-bulb temperature (see Temperature, Wet-bulb) upon the occupants of the room or upon materials stored or handled in it. Wet return, 782 Wind. Dry air is a mechanical mixture of gases composed, in percentage of Wall, walls. . air leakage through, 132 - of chimneys, 465 fire. 379 heat transmission coefficients for, 105, 112, 114, 116, 118 . radiators, output. 522 solar radiation on, 160, 161 , sound transmission coefficients for, 331 surfaces, areas of, 104 time lag through, 162 Warm air heating systems, 782 gas-fired furnaces for, 502 gravity, 417 . mechanical, 403 Washers, air, 201, 406, 772 capacity of, 203 specifications for, 204 types of, 201 Water, 41 ' boiling point of, 26 . - . circulating, temperature of, 206, 663 ' from city mains, 180, 194 cooling, - equipment, 204 efficiency of, 208 . ' quantity, 176, 206 temperature, 206 composition of, 26 - density of, 26 domestic supply, 629 ` . - . in cities, 148, 158 . effect on heating requirements, 147 forces in natural ventilation, 89, 95, 131 - prevailing, direction of, 136, 158 records of velocity and direction, 148, 158 velocity on natural draft equipment, 210 average, 89, 136 147, 158 equivalent, in tall buildings. 138 used in calculations, 136 Window, windows, 91, 93 air leakage through, 135 area, 104 clearance of sash, 134 coefficients of transmission of, 125 comparison of various shades for, 163 crack, 134 measurement of, 134 solar radiation through, 163 storm sash, 134 Winter, . comfort zone, 68, 69 conditioning, apparatus for, 170 cooling in, 157 ," humidification in, 171, 526 relative humidity in, 70 temperatures, 148 wind velocities and directions, 148 Wood, woods. air speed for conveying, 380 heat transmission coefficients of, 110 x volume, as follows1: nitrogen 78.03, oxygen 20.99, argon 0.94,' carbon dioxide 0.03, and small amounts of hydrogen and other gases.' 3- Atmospheric air at sea level is given in percentage by volume as: N2 'i 77.08, O2 20.75, water vapor 1.2, A 0.93, CO2 0.03 and H2 0.01. The a) amount of water vapor varies greatly under different conditions and is frequently one of the most important constituents since it affects bodily comfort and greatly affects all kinds of hygroscopic materials. . LAW OF PARTIAL PRESSURES A mixture of dry gases and water vapor, such as atmospheric air, obeys Dalton's Law of Partial Pressures: each gas or vapor in a mixture, at a given temperature, contributes to the observed pressure the same amount that it would have exerted by itself at the same temperature had no other gas or vapor been present. If p = the observed pressure of the mixture and pi, pi, pz, etc. = the pressure of the gases or vapors corresponding to the observed temperature, then p = pi -f p% + Pi, etc. . (1) evaporation of, 211 . factor of usage, 631 flow from fixtures, 630 freezing, 663 . . .. 'Z DRY- AND WET-BULB TEMPERATURES friction losses through pipes, 637 . hammer, 560 heaters,.389, 645 . heating, 629 hot, domestic supply, 643, 645 boilers, 279, 435 demand for, 649 electric heating of, 705 " pipe sizes for, 640 storage of, 648 heating systems, 587 (see also Bot Water Heat ing Systems) . . Zero, absolute, 771 Zone, zoning, . for air conditioning systems, 172 automatic control, 281 -. .comfort, 68, 72, 773 average, 68, 69 ' extreme, 68, 69 . heat loss within, 82 control of steam heating systems, 548 for cooling of buildings, 164 for large heating systems, 603 neutral, 778 Air is said to be saturated at a given temperature when the water vapor mixed with the air is in the dry saturated condition or, what is the equiv alent, when the space occupied by the mixture holds the maximum pos sible weight of water vapor at that, temperature. If the water, vapor mixed with the dry air is superheated, i.e., if its temperature is above the temperature of saturation for the actual water vapor partial pressure, the air is not saturated. . inches of water, 777 water supply systems, 629 1International Critical Tables. . XXll I American Society of Heating and Ventilating Engineers Guide, 1936 The starting point of most applications of thermodynamic principles to air-conditioning problems is the experimental determination of the drybulb and wet-bulb temperatures, and sometimes the barometric pressure. The dry-bulb temperature of the air is the temperature indicated by any type of thermometer not affected by the water vapor content or relative humidity of the air. The wet-bulb temperature is determined by a thermo meter with its bulb encased in a fine mesh fabric bag moistened with clean water and whirled through the air until the thermometer assumes a steady temperature. This steady temperature is the result of a dynamic equilibrium between the rate at which heat is transferred from the air to the water on the bulb and the rate at which this heat is utilized in evapor ating moisture from the bulb. The rate at which heat is transferred from the air to the water is substantially proportional to the wet-bulb depres sion (t -- t'), while the rate of heat utilization in evaporation is propor tional to the difference between the saturation pressure of the water at the wet-bulb temperature and the actual partial pressure of the water vapor in the air (e1 -- e). Carrier's equation for this dynamic equilibrium is t-f B - e' 2800 - 1.31' (2a) In the form commonly used, (B - *') (i - <) (2b) where t = actual partial pressure of water vapor in the air, inches of mercury. ' = saturation pressure at wet-bulb temperature, inches of mercury. B = barometric pressure, inches of mercury. t = dry-bulb temperature, degrees Fahrenheit. /' = wet-bulb temperature, degrees Fahrenheit. Formula 2b may be used to determine the actual partial pressure of the water vapor in a dry air-water vapor mixture. Then, from Dalton's Law of Partial Pressures, Equation 1, it follows that the partial pressure of the dry air is (B -- e). If a mixture of dry air and water vapor, initially unsaturated, be cooled at constant pressure, the temperature at which condensation of the water vapor begins is called the dew-point temperature. Clearly the dew-point is the saturation temperature corresponding to the actual partial pressure, e, of the water vapor in the mixture. PROPERTIES OF AIR Density is variously defined as the mass per unit of volume, the weight per unit of volume, or the ratio of the mass, or weight, of a given volume . of a substance to the mass, or weight, of an equal volume of some other substance such as water or air under standard conditions of temperature and pressure. The term specific gravity is more commonly used to express the latter relation but, when the gram is taken as the unit of mass and the cubic centimeter as the unit of volume, density and specific gravity have 2 i f i i 4 i ij if ) 'is Chapter 1--Fundamentals of Heating and Air Conditioning the same meaning. The term specific density is sometimes used to dis tinguish the weight in pounds per cubic foot; and as here used, density is the weight in pounds of one cubic foot of a substance. The density of air decreases with increase in temperature when under constant pressure. The density of dry air at 70 F and under standard atmospheric pressure (29.92 in. of Hg) is approximately 0.075 lb (see Table 1), while that of a mixture of air and saturated water vapor at the same temperature and barometric pressure is only about 0.0743 lb. In the mixture the density of the dry air is 0.0731 and that of the vapor is 0.00115 lb (see Table 2). In order to make comparisons of air volumes or velocities it is necessary to reduce the observations to a common pressure and temperature basis. The basic pressure is usually taken as 29.92 in. of Hg, but no basic tem perature is universally recognized. Common temperatures for this purpose are 32 F, 60 F, 68 F, and 70 F. Since 70 F is the most commonly specified temperature to which rooms for human occupancy must be heated, it is usually understood, when no other temperature is specified, that 70 F is the basic temperature for measuring the volume or the velocity of air in heating and ventilating work. The specific volume of air is the volume in cubic feet occupied by one pound of the air. Under constant pressure the specific volume varies inversely as the density and directly as the absolute temperature. The specific heat of air. is the number of Btu required to raise the temperature of 1 lb of air 1 F. The specific heat at constant pressure, Cp, and that at constant volume, Cv, are different. The specific heat at constant pressure is commonly used and it varies, under a pressure of one atmosphere, from a minimum at about 32 F from which it increases with either increase or decrease of temperature. The value 0.24 is suf ficiently accurate for use at ordinary temperatures, but the values range1 from 0.2399 at 32 F to 0.2404 at 212 F, 0.2413 at 392 F, 0.243 at -108 F, and 0.252 at -301 F. The mean specific heat of water vapor at constant pressure is taken as 0.45 for all general engineering computations. Table 3 is intended to aid in determining the density of moist air, taking into'account its temperature, pressure, and moisture content. Example 1. To show the use of Table 3:. Given air at 83 F dry-bulb and 68 F wetbulb (or a depression of 15 deg) with a barometric pressure of 29.40 in. of mercury. What will be the weight of this air in pounds per cubic foot? Solution. From Table 3 the weight of saturated air at 80 F and 29.00 in. barometer is found to be 0.07034 lb per cubic foot. There is a decrease of 0.00015 lb per degree dry- bulb temperature above 80 F. There is an increase of 0.00025 lb for each 0.1 in. above 29.00 in. From the last column of Table 3 it is found that there is an increase of approxi mately 0.000035 lb per degree wet-bulb depression when the dry-bulb is 83 F,, Tabu lating the items: .. 0.07034 = weight of saturated air at 80 F and 29.00 bar. -- 0.00045 = decrement for 3 deg dry-bulb, 3 X 0.00015. ` + 0.00100 = increment for 0.4 in. bar., 4 X 0.00025. . . + 0.00053 = increment for 15 deg wet-bulb depression, 15 X 0.000035. 1 0.07142 = weight in pounds per cubic foot of air at 83 F dry-bulb, 68 F wet-bulb, 29.40 in. bar. - 3 '/ of and 1936.American Society Heating Ventilating Engineers Guide, Table 1. Properties of Dry Air2 Barometric Pressure 29.921 In. Temperature Deg F 0 10 20 30 40 SO 60 . 70 80 90 100 110 120 130 140 150 160 180 200 220 240 260 280 300 350 400 450 500 550 600 700 800 . . 900. 1000 Weight per Cu Ft Pounds Per Cent op Volume at 70 F . Btu Absorbed bt One Gu Ft Drt Am peh Deg F 0.08636 0.8680 0.02080 0.08453 0.8867 0.02039 0.08276 0.9057 0.01998 0.08107 0.9246 0.01957 0.07945 0.9434 0.01919 0.07788 0.9624 0.01881 0.07640 0.9811 .0.01846 0.07495 1.0000 0.01812 0.07356 1.0190 0.01779 0.07222 1.0380 0.01747 0.07093 . 1.0570 0.01716 0.06968 1.0756 0.01687 0.06848 1.0945 0.01659 0.06732 1.1133 0:01631 0.06620 1.1320 0.01605 0.06510 1.1512 ` 0.01578 0.06406 1.1700 0.01554 0.06205 1.2080 0.01506 . 0.06018 1.2455 0.01462 0.05840 1.2833 0.01419 0.05673 1.3212 0.01380 0.05516 1.3590 0.01343 0.05367 1.3967 0.01308 0.05225 1.4345 0.01274 0.04903 0.04618 0.04368 0.04138 0.03932 0.03746 0.03423 0.03151 0.02920 0.02720 1.5288 ' 1.6230 1.7177 , 1.8113 1.9060 > 2.0010 2.1900 : 2.3785 , . , 2.5670 , . 2.7560 0.01197 0.01130 0.01070 0.01018 0.00967 0.00923 0.00847 0.00782 0,00728 0.00680 Cu Ft Drt Am Warmed One Degree per Btu 48.08 49.05 50.05 51.10 52.11 53.17 54.18 55.19 56.21 57.25 . 58.28 59.28 60.28 61.32 62.31 63.37 64.35 t 66.40 68.41 70.48 72.46 74.46 76.46 , 78.50 83.55 88.50 93.46 98.24 103.42 108.35 118.07 127.88 137.37 . 147.07 . ' From Fan Engineering 4 Chapter 1--Fundamentals of Heating and Air Conditioning It is usual to assume that dry air, moist air, and the water vapor in the air follow the laws of perfect gases. This assumption while not absolutely true, especially with saturated vapor at temperatures much above 140 F, Table 2. Properties of Saturated Air2 Weights of Air. Vapor of Water, and Saturated Mixture of Air and Vapor at 29.921 Inches of Mercury Temp. Deg F Weight in a Cubic Foot op Mixture Btu Absorbed bt Cubic Feet Sat. Specipic One Cubic Foot Air Warmed One Heat Btu Weight or Weight or Total Weight or Sat. Am per Degree per per. Pound Drt Am . Vapor the Mixture Deg F Btu or Mixturb Pounds Pounds % Pounds 0 10 20 30 40 50 60 70 80 90 100 110 120 ; 130 140 150 160 170 . 180 190 200 210 ` 212 0.08625 0.08433 0.08246 0.08062 0.07878 0.07694 0.07506. 0.07310 0.07103 0.06879 0.06635 0.06364 0.06060 0.05715 0,05319 0.04864 0.04340 0.03734 0.03035 0.02228 ..0.01300 0.00230 0.00000 0.000068 0.000110 0.000176 0.000277 0.000409 0.000587 0.000828 0.001151 0.001578 0.002134 0.002850 0.003762 . 0.004914 . 0.006351 0.008120 0.010295 0.012936 0.016108 0.019896 0.024400 0.029715 0.035938 0.037307 0.08632 0.08444 0.08264 0.08090 0.07919 0.07753 0.07589 0.07425 0.07261 0.07092 0.06920 0.06740 0.06551 0.06350 0.06131 0.05894 0.05634 0.05345 0.05025 0.04668 0.04272 0.03824 0.03731 0.02083 48.02 0.2413 0.02039 49.05 0.2415 0.01998 50.07 0.2418 0.01958 51.07 0.2420 0.01921 52.06 0.2426 0.01885 53.05 0.2431 0.01851 54.02 0.2439 0.01819 54.97 0.2450 0.01790 55.87 0.2465 0.01762 56.76 0.2485 0.01736 57.59 0.2509 0.01714 58.35 . 0.2543 0.01695 59.00 0.2587 0.01679 59.56. . 0.2644 0.01668 59.96 ' 0.2721 0.01662 60.17 0.2820 0.01662 60.17 0.2950 0.01668 59.96 0.3121 0.01684 ' 59.38 0.3351 0.01710 58.49 0.3663 0.01749 57.18 .0.4094 0.01802 55.50 0.4712 0.01815 55.10 0.4865 aFrom Fan Engineering. is sufficiently accurate for practical purposes and it greatly simplifies computations. , Boyle's Law refers to the relation between the pressure and volume of a gas, and may be stated as follows: With temperature constant, the volume of a given weight of gas varies inversely as its absolute pressure. ' Hence, if Pi and Ps represent the initial and final absolute pressures, and Vt and F2 represent corresponding volumes of the same mass, say one pound of gas, then--V^ P or Pi Vi = _P2 F2, but since Pi Vi for any given case is : Vi Jr1 a definite constant quantity, it follows that the product of the absolute 5: T able 3. W eights of Saturated and Partly Saturated A ir for Various Barometric and H ygrometric Conditions,b Pounds per Cubic' Foot ' of andAmerican Society Heating Ventilating Engineers Guide, 1936 . 6 aFrom Fan Engineering. bA convenient and accurate chart for quickly determining the weight of air under any condition of dry-bulb, wet-bulb, and pressure is A Chart fo r Determining the Weight o f Moist A ir in Pounds Per Cubic Foot, by John E. Younger. Published In Mechanical Engineering, June, 1925. Chapter 1--Fundamentals of Heating and Air Conditioning pressure and volume of a gas is a constant, or PV = C, when T is kept constant. Any change in the pressure and volume of a gas at constant temperature is called an isothermal change. Charles' Law refers to the relation among pressure, volume, and tem perature of a gas and may be stated as follows: The volume of a given weight of gas varies directly as the absolute temperature at constant pressure, and the pressure varies directly as the absolute temperature at constant volume. Hence, when heat is added at constant volume, Vc, the resulting eHquation is P5^i = T~ri, or, for the same temperature range at constant pres- sure, P,,c, th. e rewlati.on i:s ^ = rjy, In general, for any weight of gas, W, since volume is proportional to weight, the relation among P, V, and T is where PV = WRT (3) P = the absolute pressure of the gas, pounds per square foot. V = the volume of the weight W, cubic feet. W = the weight of the gas, pounds. R = a constant depending on the nature of the gas. The^average value of R for air is 53.34. T = the absolute temperature, degrees Fahrenheit. This is the characteristic equation for a perfect gas, and while no gases are perfect in this sense, they conform so nearly that Equation 3 will apply to most engineering computations. HUMIDITY Humidity is the water vapor mixed with dry air in the atmosphere. Absolute humidity has a multiplicity of meanings, but usually the term refers to the weight of water vapor per unit volume of space occupied, expressed in grains or pounds per cubic foot. With this meaning, absolute humidity is nothing but the actual density of the water vapor in the mixture and might better be so called. A study of Keenan's Steam Tables2 indicates that water vapor, either saturated or super-heated, at partial pressures lower than 4 in..of mercury may be treated as a gas with a gas constant R of 1.21 in the characteristic equation of the gas pV = wR (t + 460). Within such limits, the density (d) of water vapor is d = -- = 1.21 (1 + 460) (Punds per cubic foot) C4*) where t *+- 4DU (grains per cubic foot) = actual partial pressure of vapor, inches of mercury. ./ = dry-bulb temperature, degrees Fahrenheit. 'Published by American Society of Mechanical Engineers, see abstract in Table 6. . 7' (4b) of and 1936American Society Heating Ventilating EngineersGuide, Specific Humidity It simplifies many problems which deal with mixtures of dry air and water vapor to express the weight or the mass of the vapor in terms of the weight or the mass of dry air. If the weight of the water vapor in a mixture be divided by the weight of the dry air, and the weight of dry air be made unity, we have an expression of the weight of water vapor carried by a unit weight of dry air. This relation has no generally accepted name: It has been variously called: mixing ratio, proportionate humidity, mass or density ratio, absolute humidity, and specific humidity. Of all these terms specific humidity is the most suggestive of the meaning which it is desired to express and it has found considerable use in this sense even though it is defined in International Critical Tables as the ratio of the mass of vapor to the total mass. It will be understood here that specific humidity refers to the weight of,waiter vapor in pounds carried by one pound of dry air. ' The gas constant for dry air,, when the partial pressure of the air is expressed in inches of Hg, is 0.753; so that the specific humidity, if represented by W, is W= e - ^ Be 1.21 (t + 460) ' 0.753 + 460) " ; = 0.622 (pounds) (5a) . :.. . = 4354 ( (grains) where ` e = actual partial pressure of vapor, inches of mercury. B total pressure'of mixture (barometric pressure), inches of mercury. (5b) Relative Humidity , , Relative humidity (4>) is either the ratio of the actual partial pressure, e, of the water vapor in the air to the saturation pressure, et, at the drybulb temperature, or the ratio of the actual density, d, of the vapor to the density of saturated vapor, dt, at the dry-bulb temperature. That is: . . : * = i= * . The relative humidity of a given mixture at a .given temperature is riot the same as the specific humidity, W, of the mixture divided by the specific humidity, Wt, of saturated vapor at the same temperature, for from Equations 5a and 6 W_ -0622 Wt 0622 te) <P (B-et) .B -- <het .'-"(7) The specific humidity of an unsaturated air-vapor mixture cannot, . therefore, be accurately found by multiplying the specific humidity of saturated vapor by its relative humidity ; although the error is usually small especially when the relative humidity is high. With a relative humidity of 100 per cent, the dry-bulb, wet-bulb, and 8 : Chapter 1--Fundamentals of Heating and Air Conditioning dew-point temperatures are equal. With a relative humidity less than 100 per cent, the dry-bulb exceeds the wet-bulb, and the wet-bulb exceeds the dew-point temperature. RELATION OF DEW POiNT TO RELATIVE HUMIDITY A peculiar relationship exists between the dew point and the relative humidity and this is found most useful in air conditioning work: This relationship is, that for a fixed relative humidity there is substantially a constant difference between the dew point and the dry-bulb temperature over a considerable temperature range. Table 4, giving the dry-bulb and dew-point temperatures and the dew-point differentials for 50 per cent relative humidity, illustrates this relationship clearly. Table 4. Dry-Bulb and Dew-Point Temperatures for 50 Per Cent Relative Humidity Dry-bulb temperature----------------------------- 65.0 Dew-point temperature.--...------ ------------- - 45,8 Difference between dew-point and dry- bulb temperature----------- ----------- -------- 19.2 70.0 50.5 19.5 75.0 80.0 85.0 90.0 55.25 59.75 64:25 68.75 19.75 20.25 20.75 21.25 It will be seen from an inspection of this table that the difference between the dew-point temperature and the room temperature is approxi mately 20 deg throughout this range of dry-buib temperatures or, to be more exact, the differential increases only 10 per cent for a range of , practically 25 deg. .................. This principle holds true for-other humidities and is due to the fact that the pressure of the water vapor practically doubles for every 20 deg through this range.: f /. ' '- : The approximate relative humidity for any differerice between dew point and dry-bulb temperature may be expressed in per cent as: | ; ; . . 100 .- , where :; ' ti = dew-point temperature. I. .j . ; This principle is very useful in determining the available cooling effect obtainable with- saturated-air when a desired relative humidity is to be . maintained in a room, even though there may be a wide variation in roofn Temperature. This problem is one which applies to certain industrial con ditions, such as those in cotton mills and tobacco factories, where re latively high humidities are carried and where one of the principal prob lems is to-remove the-heat generated-by-the-machinery. It also-permits the use of a differential thermostat, responsive to both the room temperature and the dew-point temperature, to control the relative humidity in the room. ; Table 5 gives, for different temperatures, the density of saturated vapor, .' ' "' 9 ' '' American Society of Heating and Ventilating Engineers Guide, 1936 ace 77777oo^ 77777 1 M M p t'l MW ts 1gggM g< 10 ? T a b l e 5. P r o p e r tie s of Sa t u r a t e d W a t e r V apor w it h A ir -a t L o w T e m p e r a tu r e s * '3 ata. 1^R*Q 1 gOO-vH oooo '3 < 3 oO"-h Or* oo oo oooo oo 3, O >*noooHw wrJ< ooh 00 00 CO 00 00 oo oo oo on oo a< i <5 i *5 a 0 1 c a s S 3 i *5 as . Is* .1 3 >% coei < cot>. *S^i0<*-t Mill In, of Hg --- 1 eocpoocov-' tiO0 0055N16Q0<CP05 d............ * * * * 0.735 .805 .892 .989 1.098, ; 1.208 1.317 1.444 1.575 .1.728 1.889 2.087 2.292 2.611 2.742 2.983 3.258 3.543 . 3.872 4.213 l ! d s & 3 Founds X KM Grains Pounds X ICM O 1 o fl lb of Dry Air ' of 1 Dry lb Air o+f Vapor to Saturate it ' 0.1350 .1503 .1660 .1832 .2019 1 0.000693 0.000049 .000768 .000054 .000843 | .000059 .000928 .000065 1 j .001019' .000071 0.005738 .006362 .007027 .007755 .008545 0.00040 .00045 .00049 | .00054 .00060 8.31 8.33 8.36 8.38 8.41 0.2235 . .2451 . .2662 .2967 .3286 0.001125 .001230 .001332 .001480 .001635 0.000079 I 0.009459 | .000086 .01037 .000093 .01127 1 1 .00010 .01256 . .00012 .01391 1 0.00066 .00073 .00079 .00088 .00097 0.3610 .3954 .4382 .4858 .5393 0.001791 .001956 .002161 .002388 .002644 0.00013 .00014 .00015 .00017 .00019 0.01528 0.00107 .01674 1 .00117 ; .01854 .00130 .02056 | .00144 .02283 - .00160 8.56 8.58 8.61 8.63 8.66 | | 8.56 8.58 8.61 8.63 8.66 i 00^1 CO to 00 00 00 CO00 00 CO6>-f4.CfO*NN00 0h0 OOOcOdoo^ 00 CO 0000 00 00 oo 00 00 00 sf04sCROfsC-ROfsCCOOgCO o 0.5934 .6469 .7093 .7736 .8488 0.002900 0.00020 .003153 .00022 .003447 .00024 .003749 .00026 .004101 | .00029 0.02511 .02738 .03002 .03274 .03593 0.00176 .00192 .00210 .00229 .00252 0.9279 1.0251 1.1258 1.2334 1.3469 0.004471 0.00031 .004925 ! .00035 .005393 .00038 .005892 | .00041 .006415 .00045 0.03927 .04339 .04765 .05220 .05701 8.81 . 8.83 8.86 8.89 8.91 R* S-R^l COOOh~Hh^<h CO oo 00 1.4652 1.6003 1.7403 1.9019 2.0694 0.006960 0.00049 1 .007580 i .00053 .008219 .00058 .008958 ! .00063 .009719 .00068 0.06202 1 .06773 .07366 I .08050 .08759 0.00434 I .00474 1 .00516 . 1 .00564 1 .00613 8.94 8.96 8.99 9.01 0.04 2.2630 2.4637 2.6784 2.9196 3.1781 0.010599 . .011512 .012480 , .013560 ,014721 0.00074 .00081 .00087 .00095 .00103 0.09578 .1043 .1134 .1236 .1345 0.00705 .00730 .00794 .00865 .00942 9.06 9.09 9.11 9.14 9.16 tCa4t0torotQcoCc4o ^NNr*NeoWcoMd II 1 1 1 Dry Air OF . Datum -31.71 -31.46 -31.21 -30.96 -30.71 -26.74 -26.49 -26.24 -26.00 -25.75 (MM h* 00 O ow rjl>Rf * cort - 7M M " Compiled by W . M . Sawdon, vapor pressures converted from International Critical Tables. 5tcO4w*tt~*Ho UC)4C4!NR<NfCN*> 111I1 00re*o-o*occoo CO CO CO Co CO 11111 Mo*Nr~NRN*<Me* NoNoMooNooNoo Mill '-i in r- OwO005j05 05 11M1 i Vapor 32 F Datum i Dry Air with Vapor to Saturate it 1000.7 1001.2 1001.6 i 1002.1 1002.6 1 -31.71 -31.46 -31.21 i -30.96 . -30.71 ORj* w01iOmf~ NXJ OeoeOoo* 01 Mill 1003.0 1003.4 1003.9 1004.3 1004.8 | 1005.2 1005.7 1006.1 1006.6 1007.0 i -29.22 -28.97 -28.72 | -28.47 -28.23 COtC*OOO*0) tC~O fC~O hCO-1M~ (CNO II111 1007.5 1007.9 1008.4 1008.8 1009.3 -26.74 -26.49 -26.24 -26.00 -25.75 . 1012.0 1012.4 1 1012.9 1013.3 1013.8 , -25.50 -25.26 -25.01 -24.76 1 -24.51 1014.2 1014.7 1015.1 1015.6 1016.0 -24.27 -24.02 . -23.78 -23.53 . -23.28 3 Chapter 1--Fundamentals of Heating and Air Conditioning s0. r* oo l l*-! f~ t~ oo o o s 3 o W .2 . P ts ea of if -1 pa 0 *3 > 0 < I |J 1 !x ao, go 5 1 oif fi !' "Bok X g r ' e< r o CoO03 <- GC0O0CChO.C0 Mill 1 M l r . 11 sd kj & o d Pounds XHM Grains Grains of 1 lb of Dry Air- kcolTcoFcOo eo `l-l ill i i -w; 0C~Rf~f<f~t~f- tt'-0t~-t- t^h^*fN0- h*-f~ M 1 M M II 1 r3-oCo0ctoo-!ri-Htooo r-t-co, 10.64 1 ! 11.53 12.51 13.53 . 14.69 , 16.87 17.20 18.58 20.10 21.72 ' 1 23.47 25.34 27.29 29.52 31.81 ' h-0^tO0"a R?rC-OR* T* ' 49.87 63.59 57.65 61.81 86.41 71.17 76.64 82.28 88.19 94.62 R0Hth->^. Rff~'VO'Vrt'^* 3.4604 3.7507 4.0837 4.4281 4.S156 5.2264 5.6635 6.1449 6.6459 7.2157 7.7953 8.4486 0.1265 0,8731 10.669 11.517 12.436 13.394 14.480 15.614 16.883 18.170 19.628 21.141 22.757 24.496 26.323 28.318 30.361 32.621 0.015990 i .017284 .018767 .020292 .022009 0.00112 .00121 .00131 .00142 .00154 0.023817 .025738 .027851 .030041 , .032530 0.00167 .00180 .00195 .00210 .00228 0.035040 .037885 .040817 1 .044037 .047463 0.051151 .055082 .059165 .063831 .068605 0.073933 0.00518 .079405 .00556 .085510 .00590 1 .091865 .00643 .098632 .00690 1 0,10590 .11350 .12179 .13024 . 13959 0.14922 .16028 . 17.164 .18350 .19638 0.01044 .01122 .01201 .01285 .01375 ot*R-jo<(o.o*5k**fr~ hRf.0^tt"^*C^O i5 (RNf IN in oCO cCooO iliii 88888 o * ' * ' - O; 0.1465 .1588 .1729 .1875 .2039 0.2212 . .2397 .2601 .2813 .3054 1 0.3290 .3570 .3863 .4170 1 .4516 0.7146 .7694 .8308 :8948 .9632 1.037 1.114 1.109 1.285 1.381 1.480 1.593 1.711 1.833 1.967 0.01026 .01112 . .01210 .01312 .01427 0.01548 .01678 .01821 .01969 .02138 1 0.02309 | .02503 I .02704 1 .02925 1 .03101 0.03415 .03688 .03972 .04296 .04629 0.05002 .05386 .05810 1 1 .06264 1 .06742 ! 0.07259 .07708 .08393 .08905 .09607 0.10360 .11151 .11977 .12831 .13769 oo 9.19 9.21 9.23 9.26 9.29 0.44 9.46 0.49 0.51 0.54 9.82 9.84 9.87 9.89 9.02 OO IMM o M1M ^Compiled by W . M . Sawdon, vapor pressures converted from International Critical Tables. of 1 lb Dry Air of + Vapor to ' Saturate it *-R c-oi e^<ocoeo-^<1 'F^^1 Cf-^t^~*ff~~f- 0.44 9.46 0.49 9.51 0.54 9.82 0.84 9.87 9.89 9.92 9.94 9.97 9.99 10.02 10.04 T}< T#> 71777 H^HHH Mill r-T~ ^ d 0d*oW`CoJdHH II II 1 II 1 1 1 0MJ0NC0JIC0*I0N 11111 kdf~N^C'-Or'J' Rj`0-tjCf~4 O Rf CO 03 Wodoo-*-< Dry Air OF Datum Dry Air with Vapor to Saturate . it ^r-too CSNW0J 1 II 1 1 hhohoohh r*rcoo ^ooe*ctokoCoOo ^oo^oo f^ Cg^'o-o* e>i-<*- - 77777 -18.13 -17.89 -17,64 -17.40 -17.16 OOO t~.f~f~.f~ I I 1 i r 77777 77771 1018.7 1019.2 1019.6 1020.1 1Q2Q.5 -21.81 -21.50 -21.32 -21.07 j -20,83 1021.0 ! 1021.4 , 1021.9 1022.3 1022.8 1023.2. 1023.7 1024.1 1024.6 1025.0 * ONON ONONCOONt~ , 1 1027.7 1028:2 1028.6 1029,1 1029.5 -16.90 -r 16.66 -16.41 -16.17 -15.93 77777. rT" Rj' ^*< American Society of Heating and Ventilating Engineers Guide, 1.936 H' 12 T a b l e 5. Pr o p e r tie s of Sa t u r a t e d W a t e r V apor w it h A ir a t L o w T e m p e r a tu r e s 8 (C o n t in u e d ) 3 te 'g ' - B Oo 5 8 .ts a C*0 8 a o i* 1 O PS s -i&i . r* oJ .o fa 9 o SO3. as lx *o d' i h L b per Sq In . . .We ig h t of Saturated Vapor J per lb o f D ry A ir G ra in s I, -V olume in C u F t B arometer, 29.92 n . H a o f 1 lb o f : D ry A ir : 3 a oe * lx cs C-* r-B (N N- OOHHH WMNNN ooooo 22222 r-- O 05 'J* - OOHHH 22222 ^}* 00 CO 00 <*' .HOhOHcoHHNH^C<HGco ^ t" 1 05 05 05 05 22222 0^l0O5OcoOt~UcJo iIoftttOjtiOctoQntQh lO c-eoji tnJ-< Bji . CO CO CO -rj< 22222 fN Tt* NO 05 CO CO CO -e}< -e*< 22222 IONONU5 >$<^iOiOtO tOCDCOCDCO 222 ooooo to N. Q <N to to lO LO 22222 till OOIO ' ieloHtoeHoeHoF-^HNCO- Mill OOOJvHiO F- N- CO CD COtOC4C4^L lO lO N- CO ONNOrt- FHcC>oH4NCc4s^0c4odto 1 II i 1 . F0-4t0o4HrCCOf tOCoO"tONCO-" 1 1 I II 49.808 63.443 57.127 61.302 65.526 70.242 75.154 80.311 85.911 91.854 98.191 104.63 111.94 119.41^ 127.47 135.92 144.90 154.58 164.70 175.65 186.80 199.18 . 211.81 225.56 1 . 239.90 . 255.18 271.34 288.09 306.36 325.08 344.33 364.57 ' 388.64 413.10 438.20 0.20993 0.01470 .22469 .01573 .23958 .01677 .25645 .01795 .27344 ' .01914 2.108 2.262 2.418 2.595 2.773 ' 0.14756 .15834: .16926 1 .18165 .19411: 0.29239 : .31207 1 .33267 .35499 .37862 0.02047 2.973. 0.20811, .02184 3.181 .22267 | .02329 > 3.399 .23793' .02485 3.636 .25452 1 .02650 3.888 .27216. 0.40376 0.02826 .42917 .03004 .45808 , .03207 .48744 ! .03412 : .51905 .03633 4.156 4.428 4.738 5.054 5.395 0.29092 .30996 : .33166 .35378; .37765| 0.55213 .58722 .62493 .66426 : .70672 0.03865 5.753 .04111 6.133 .04375 6.643 .04650 6.971 .04947 7.435 0.402711 .42931 .45801 .48797 .52045 0.7498 .7976 .8461 .8989 ; .9538 0.05249 .05583 . .05922 .06292 .06677 7.907 8.431 , 8.965 9.548 1 10.16,. 0.55349 .59017 i .62755 .66836 .1 .71120 1.0122 0.07085 1.0738 .07517 1.1374 .07962 ; 1.2067 ` .08447 1.2774 .08942 10.80 11.49 12.20 12.97 13.76 0.75600 ' .80430 .85400 .90790 .96320 1.3499 1.4260 1.5166 1.6083 1.7021 0.09449 .09982 .10616 ;11258 .11914 14.58 15.43 16.45 17.49' 18.55 ' ' 1:0206 1.0801 1.1515 1.2243 1.2985 COO*hCDtocCoO .IHO"tetoOig.o Mco+CO rf* }i : oaCOoCOoCsOCO iCcO ^COcCoO oCO*C^D ocon^-co 1 1 III IIIII ,NhO ^e-JNi ---.0Kh^0-<im00'- . li I i.i `Compiled by W . M . Sawdon, vapor, pressures converted from International Critical Tables. N- CJ to *0 CD CO CO CO 2222 NlCNO cDN-t^N-oO ooooo C50510N-0 CD N- N- h~ CO ooooo ooooo NW5SON 0000000505 ooooo CCO5CMO5CNO -005 moocon cd to co*h moocoo*o CtH^ONN-c-^o'C'i*o oooon.n>n 1 ' 11 ' 11 1 ' ' coo^eo CO CO "< CD 0505050000 111 '' a CO CO CO CO ooooo 77771 000*DCO o<^h*h>hh 77777 NONICN mcgnnn 77777 SS2J5S^ ^MON-tO T7mi . Vapor 32 F D atum 1 : D ry A ir w ith Vapor to S aturate it 1032.2 . -1 4 .4 6 1032.7 J; -1 4 .2 1 1033.1 ; -1 3 .9 7 1033.6 -1 3 .7 2 1034.0 -1 3 .4 7 1034.5 1034.9 1035:4 1035.8 1036.3 ` ; : . -13.23 -12.99 12.74 -12.49 -12.26 1036.7 1037.2 1037.6 1038.1 1038.5 , ; ; ; -12.01 -11.76 -11.62 -11.27 -11.02 1039:0 1 -1 0 .7 8 1039.4 : -1 0 .6 4 1039.9 -1 0 .2 8 1040.3 -1 0 .0 4 1040.8 -9.795 1041.2 1041.7 1042.1 1042.6 1043.0 -9.547 -9.300 -9.053 -8.805 1 -8.557 1043.5 1043.9 1044.4 1044.8 1045.3 -8.309 -8.060 -7.812 -7.562 -7.313 1045.7 1046.2 1046.6 1047.1 1047.5 -7.064 -6.814 -6.562 -6.310 -6.057 . f t .f Chapter 1--Fundamentals of Heating and Air Conditioning . H 13 P r o p e r tie s of Sa t u r a t e d W a t e r V apor w it h A ir a t L ow T e m p e r a tu r e s8 (C o n c lu d e d ) 3 g 1 O O 1 & -*.5 P e* fcg i\ >o 5 5 fOib 2a o *o > a E as h x O PS g2 fas Pb m -ef CO Cd v-- 0v--0 N^> CV--O< /-gfa- ; : i: I! 1, l i. jvi i i fa OA4o?.. o oCNHVMtCCoOOcNCoTOjNstOoNoNr^ CON-CD TTT77 7 I' 1 1 1. II 1 1 In. of Hg Lb per Sq In. Founds X 1(H Grains P. Founds X 10-* Grains of 1 ib of Dry Air of 1 lb Dry Air o+f Vapor to Saturate it ' aCDO0co0'1e--o< MrC--J rlNONNJNeOI'Ntfi - OCbDjtJCoOOcToOfcCH'OjoCrsNt 1262.0. 1337. 1416. 1496. 1584. 1675.0 1772. 1874/ 1980. 2093. 464.87 492.67 522.64 553.09 585.51 619.89 656.73 695.54 , 734.84 , 1 778.06 822.76 870.41 920.51 972.58 1028.1 1085.6 1147.0 1209.8 1229.0 1348.3 1423.5 1500.6 1582.6 1668.6 1758.5 co HCt0oO0 . 1.8016 1 1.9049 2.0162 2.1287 2.2484 0.12611 .13334 .14113 .14901 .15739 2.3750 2.5105 , 2.6527 2.7963 2.9542 0.16625 .17574 .18569 j .19574 .20679 3.1168 3.2899 3.4714 .3.6596 3.8599 4.0666 0.28466 1 1 4.2871 .30009 1 ! 4.5120 .31584 1 | 4.5734 . .32014 5.0066 .35046 ,6.2738 5.5473 5.8379 6.1414 6.4583 0.36917, .38831 .40865 .42990 .45208 6.7914 0.47500 oBol oDo00-*^o COOi0tO0 lONCOD H eoCcOoGOe*o-<^C^O I-eQriGTjHOlOw^Oe^IDt/ aHoOoNoOeOoHt>oHo o 1.3776 1.4602 1.5491 1.6394 1.7353 26.25 27.81 29.45 31.12 j 32.95 1.8375 1.9467 2.0615 2.1784 . 2.3065 2.4388 2.5802 2.7286 2.8833 3.0478 3.2186 3.4006 3.5875 3.6442 3.9984 60.30 63.57 v 1 - 67.05 70.69 . 74.60 4.2210 4.4499 4.6935 4.9483 5.2150 78.52 5.5000 10.95 ! 10.97 11.00 11.02 , 11.05 11.07 11.10 11.13 11.15 1 11.18 11.45 11.48 11.50 11.53 11.55 11.58 O<nCeOq tcOsOcsOco ecooctoooeooo^je*o^ HHHHH 10.95 10.97 11.00 11.02 11.05 ; 11.07 11.10 11.13 I 11.15 11.18 11.21 11.24 11.26 r 11.29 11.31 ! ! ; 11.34 11.36 11.39 11.41 11.44 11.46 11.49 11.51 11.54 11.57 11.59 0OCN0Ot1COOO0.Cd<CNJO.CNCGOO-.tOCQOO. , NCCNOO-- Compiled by W . M . Sawdon, vapor pressures Converted from International Critical Tables. Q < > oGNOcMCoO)oCtQsOoOtoo*-0^*0 III M sOh-inON-Dc"5*OcNOoO.N^ (DiOiOcOco [MM Dry Air 0r Datum Vapor 32 F Datum Dry Air with Vapor i ito Saturate ' iflHNNN oo*AC*r tDlD>DU0^}< 11111 1048.0 1048.4 1048.9 1049.3 1049.8 NNH o oU3oM!O-oi*O!Uo-OUoO -4.531 -4.274 -4.015 -3.758. 1 -3.497 NCOtNo-C^t4TjtOCOO ` Mill -3.604 -3.363 -3.123 -2.883 -2.642 1052.5 1052.9 1053.4 1053.8 1054.3 -2.402 -2.162 -1.921 -1.681 -1.441 1054.7 -1.917 ,, 1055.2 -1.649 1 1055.6 1 -1.380 1 1056.1 -1.131 1 1056.5 -0.8375 <*eoco Ntoo- oNto- oNto>o0to0oGtoO o -1.201 -0.9604 -0.7203 -0.4802 -0.2401 -0.5636 -0.2882 -0.01098 +0.2679 +0.5487 1059.2 +0.8317 American Society of Heating and Ventilating Engineers Guide, 1936 a: r w*CSM* *>t-oo w^CSCO'* t-oocs cs --csccs*ewsc** cs cs.fc--* 0c0s cs nrHwCSCc0 To* C 14 T a b l e 5. Pr o p e r tie s of Sa t u r a t e d W a t e r V apor w it h A ir , 0 F to 200 F11 3 $ % l & 1. O . 5s gs M CS* Bo Ega >i < & OS * < Ia> ' g mj tok oHffl I9 0 1 taa I 28. f ; In. of Hg Lb per 8q In. Pounds a g a 1 1 of 1 lb of Dry Air 0.03773 .03975 .04186 .04409 , .04645 0.04886 .05144 .05412 .05692 .05988 0,06295 .06618 .06958 .07309 .07677 0.08067 .08469 .08895 .09337 ,09797 i 0.1028 .1078 .1132 .1186 .1244 0.1304 .1366 ! .1432 i .1500 .1571 i 0.1645 .1722 .1803 .1879 .1957 0.01853 .01963 .02056 .02166 .02282 0.02400 .02527 .02658 : .02796 .02941 0.03092 .03251 .03418 .03590 ** .03771 0.03963 .04160 .04369 .04586 .04812 0.05050 ' .05295 .05560 .05826 .06111 0.06405 .06710 .07034 .07368 .07717 0.08080 .08458 .08856 .09230 .09610 0.000067914 .000071395 .000075021 .000078851 , .000082890 0.475 .500 .525 .552 .580 0.000087005 .000091399 .000095955 .00010070 .00010572 0.00011090 .00011634 .00012206 .00012794 .00013410 0.776 .814 .854 .896 .939 0.00014082 .00014732 ,00015440 .00016174 .00016935 0.984 1.031 1.081 1.132 1.185 0.00017747 .00018564 .00019439 .00020335 .00021276 0.00022255 1.558 1 .00023278 1.629 .00024342 1.704 .00025445 1.781 .00026597 1.862 0.00027797 .00029043 .00030343 .00031471 .00032690 1.946 2.033 2.124 2.203 2.288 OC* to to 0.0007852 .0008275 .0008714 .0009179 .0009671 i 0.001017 .001071 .001127 .001186 .001247 0.001311 .001379 .001450 .001523 .001600 9.18 9.65 10.15 10.66 11.20 0.001682 .001766 .001855 .001947 1 .002043 0.002144 | .002250 , .002361 1 .002476 .002596 0.002722 .002853 .002991 .003133 .003283 19.05 19.97 20.94 21.93 22.99 0.003439 24.07 .003601 1 25.21 .003771 ! 26.40 .003931 27.52 .004094 28.66 tt---COCJOCOC<9 -it--coecoo*t-<"> CS CS C*3 Tf r- oo CC-SS'SCS*C-OCCTfSO< 0t>0< or-^on^tt-- c^*0o0COetoo to to to co oo 11.96 11.98 12.00 12.03 12.06 12.08 12.11 12.13 12.16 12.18 12.21 12.23 12.26 12.28 12.31 aCorapiled by W . M . Sawdon, vapor pressures converted from International Critical Tables. O"CC0OT)t^H CS CS CS CS CS CCOO COCCOOT-}* C'CO CS CS CS CSC* ctos to to oCO 0co0 0to0oCOCO' to CtoO to 0to000 cCOoCOo0o0-*<o of 1 lb of Dry Air -jVapor to Saturate it 11.59 11.62 11.64 11.67 11.70 11.85 11.88 11.91 11.93 11.98 11.99 12.01 12.04 12.07 12.09 csHHoCoCcSo CS CSCS CSC* 12.26 12.29 12.32 12.34 12.37 CS CS CS CO CO O goooocs C3OCOO'OtC0~3-3* 0t-0 0c0o0CtS0- 0^0 0t0 oQonCSrN-rH-tr-i-Qt- Dry Air OF Datum 0.0000 .2401 .4801 .7201 .9601 1.200 1.440 1.680 1.920 2.160 7.197 7.437 7.677 7.917 8.157 t-- cs --< ggg ooooo Vapor 32 F : Datum I i 1059.2 1059.7 1060.1 1060.6 1061.0 1 1061.5 1061.9 1062.4 1062.8 1063.3 1066.0 1066.4 1066.9 1067.3 1067.8 1088.2 1068.7 1069.1 1069.6 1070.0 1070.5 1070.9 1071.4 1071.8 1072.3 1072.7 1073.2 1073.6 1074.1 1074.5 i C00Mtt--10t0--<0-0*^0<0 cs cscs coco Dry Air with Vapor , to Saturate it 0.8317 . 1.117 1.404 1.694 1.986 3.795 4.108 4.424 4.742 5.064 5.392 5.722 6.058 6.397 6.741 7.088 7.443 7.802 8.166 8.536 8.912 ! 9.292 9.682 10.075 10.477 10.886 ; 11.302 11.726 12.139 12.556 1 1 . i t < s i i- Chapter 1--Fundamentals of Heating and Air Conditioning 3 SIf5 ' t-o^^oooocesto- Hffl t-- cocs Ja S3 oM0s. ^ cs 'C csoooocooo wHt-to-^Oot- ct-ooot--oSoic*s* CtQ--.w*eHoCS escoco^jjl t-- oo2 Oes Oeshc* hcscCsS 'CeSc cscTsf cscs cs tc-stc-sccoscs cs Ococ*-o< ccso ccoo 15 / T a b l e 5. P r o p e r t ie s o f Sa t u r a t e d W a t e r V a p o r w it h A ir , 0 F t o 200 Fa (C o n t in u e d ) 6 oO H< & w 3 O c* 0*5 isis > 23 CQ oO0sk > a- g 3 c a 0 *2 eo 0 R is 1 28 f> & O *o 4 Lb per Sq In. Pounds S e o 3 aa P- of 1 lb of Dry Air . t-t-t-t-00 OOOOCOffl -o*o*o C--HS *C4S CS CSWCS es cscs cscs CSCS CO CO CO t-oo p-e*co* - WW^o*** lflt--00 W*`"J*-s* ^ hcsco^j 0.20360 .21195 . .22050 , .22925 , .23842 0.24778 .25755 .26773 .27832 .28911 0.30031 .31191 .32393 .33635 .34917 0.36241 .37625 .39051 .40496 .42003 0.43570 .45179 .46828 .48538 .60310 0.52142 .54035 .55970 .57985 .60042 0.62179 .64378 .66638 .68980 .71382 te--ses r^oeto-cs 0.1000 .1041 .1083 .1126 .1171 0.1475 .1532 .1591 >1652 .1715 0.1780 .1848 .1918 .1989 .2063 0.2140 .2219 .2300 .2384 .2471 0.2561 .2654 .2749 .2848 .2949 0.3054 .3162 .3273 .3388 .3506 0.0003394 .0003527 .0003862 , .0003799 .0003943 2.376 2.469 2.563 2.660 2.760 0.004262 .004438 .004618 , .004803 .004996 i 29.83 31.07 32.33 33.62 , 34.97 12.46 12.48 12.51 12.53 12.56 0.0004090 .0004243 .0004401 .0004566 .0004735 2.863 2.970 3.081 3.196 3.315 1 0.005194 .005401 .005616 .005840 .006069 36.36 , 37.80 39.31 40.88 42.48 12.59 12.81 12.64 12.66 12.69 0.0004909 .0005088 .0005274 .0005465 .0005663 . 3.436 3.562 3.692 3.826 3.964. 0.008306 .006553 .006808 .007072 .007345 44.14 45.87 47.66 49.50 51.42 0.0005866 .0006078 .0006296 .00Q6516 .0006746 4.106 4.255 4.407 4.561 4.722 0.007626 .007921 .008226 .008534 .008856 53.38 55,45 57.58 59.74 61.99 CO t- rcOsC0S0 CO c-isaoocos roo hoo VtOtH-t^- tt---O00 C0O0 00 00 0.0006984 .0007228 .0007477 .0007735 .0008003 4.889 5.060 5.234 5.415 5.602 0.009102 .009536 .009890 .01026 .01064 0.0008278 .0008562 .0008852 .0009153 .0009460 oC^^vO^a^cosces^ss ooooo o t-co^-Sto>- ccss 13.09 13.11 13.14 13.16 13.19 CSCS CSCS CO eoeoeoeoco 0.0009778 .0010105 .0010440 .0010816 .0011140 6.845 7.074 7.308 7.571 7.798 0.01320 .01368 .01417 .01468 .01520 92.40 95.76 99.19 102.8 106.4 *wft>t-oo ^csco^ <e5pt-00 aCompiled by W . M ; Sawdon. vapor pressures converted from International Critical Tables. l JO >% Q of 1 lb Dry Air o+f Vapor to Saturate it Dry Air OF Datum 12.54 12,57 12.60 12.63 12.66 8.397 8.636 8.876 9.116 9.356 9.596 9.836 10.08 10.32 | 10.56 10.80 11.04 . 11.28 11.52 11.76 CeSoTt-f^tH- es cscs cscs ct-st-r-cooo o**oto-oocoo OcsOO-c-s' ^HWIcCSsCSC* ccsoeoeoc^s'O* cs cs es cs es cs es cs cs cs cs coco coco CO CO CO CO CO CO CO CO CO CO 13,49 13.53 13.57 13.60 13.64 CaoOotc-ro* 13.19 13.43 13.67 13.91 14.15 14.39 14.63 14.87 15.11 15.35. 1 Vapor 32 F Datum 1075.0 1075.4 1075.9 1076.3 1076.8 1077.2 1077.7 1078.1 1078.6 1 1079.0 1079.5 1079.9 1080.4 1080.8 1081.3 i 1081.7 1082.2 1082.6 1083.1 1083.5 1084.0 1084.4 1084.9 1085.3 1085.8 1086.2 1086.7 1087.1 1087.6 1088.0 1088.5 1088.9 1089.4 1089.8 1090.3 American Society of Heating and Ventilating Engineers Guide, 1936 16 i; :e T a b l e 5. Pr o per ties of Sa t u r a t e d W a t e r V apor w it h A ir , 0 F to 200 Fa (C o n t in u e d ) a H A. ga Ogo : H A S P r1 O i li CO oPa Chapter 1--Fundamentals of Heating and Air Conditioning >4 % a E m BOa o a !* 0' 1 Se* go. s^* cgo - . 1. ' 1^' ?- ' Ca? bfl' w * d Lb per Sq In. Pounds 1 Grains Pounds Grains of lib of Dry Air of 1 lb of Dry Air + Vapor to Saturate it Ncjct<tcN<OcoeNo .tcoocco-coc<u^v SON'flt' OCDCCJD>CODCNDOC* Ct'tJ'NOOCO*.QCOO CD 00 CO co^^uoo eccdsr-occw<3> 2.2414 2.3084 2.3770 , 2.4473 2.5196 1 1.1009 1.1338 1.1675 1.2020 1.2375 0.0032786 .0033715 .0034650 .0035612 .0036603 22.95 23.60 24.26 24.93 , 25.62 0.05037 .05200 .05368 .05541 .05719 CUCO5jTCCjOO4CCUO-3COfaOO.OO'f T#t ajl Tjt ^ 15.37 . 15.44 , 15.50 ; 15.57 15.64 110 2.5939 1.274 0.0037622 111 2.6692 1.311 .0038669 112 2.7486 1.350 .0039729 113 2.8280 1.389 .0040816 114 2.9094 1.429 .0041911 2.9929 3.0784 3.1660 3.2576 3.3492 1.470 1 .5 1 2 1.555 1.600 1.645 1 0.0043047 .0044208 ; .0045372 i .0046620 i .0047846 COCO>DCO eoid coco CC<OCt<^Ct-<CCOJCJ eoOtoi-HtoCcJoCcOo 0.05904 .06092 .06292 .06493 .06700 0.06913 .07134 .07361 .07600 .07840 cocoon Tjl ^ 483.9 499.4 515.3 532.0 548.8 16.08 16.18 16.24 16.32 16.41 i intoc-eo . r<*c-<iccjjerJoc^i tDotooCeDoftt-0t0OCDCDCDO tCoJCcoJC<Co<oC< . fC-CHOCCOJCCOOC'C* 3.4449 3.5406 3.6404 3.7422 3.8460 3.9519 4.0618 4.1718 4.2858 4.4039 ! 4.5220 4.6441 4.7703 4.8986 5.0289 1 1 1.692 1 .-739 1.788 1.838 1.889 1.941 1 .995 2.049 2.105 2.163 0.0049115 .005040 1 .005173 .005311 1 .005450 34.38 35.28 36.21 i 37.18 38.15 0.005590 .005734 .005882 .006031 .006188 39.13 I 40.14 41.17 ; 42.22 43.32 0.006344 44.41 .006504 ! 45.53 .006671 ' 46.70 .006839 47.87. 1 .007010 49.07 W<* f--*t'-<* *" ^* ^* ^ ^< ** 0.08093 566.5 .08348 584.4 1 .08616 603.1 ! .08892 622.4 .09175 642.3 1 0.09466 .09770 .1008 .1040 .1074 0.1107 ! .1143 .1180 ; 1218 1 ! .1257 1 14.85 14.88 14.90 14.93 14.95 16.96 17.06 17.17 17.27 17.38 Oa* rCtOWt-l0O0N NHNHNHNHNH 5.1633 .-5.2997 ! 5.4402 5.5827, 5.7293 0.007185, .007364 . .007547 .007732 .007923 50.30 51.55 52.83 54.12 55.46 14.98 15.00 15.03 15.05 15.08 18.10. 18.23 18.36 18.50 18.65 COcOOOO *-* CO (cCDOjeOoOOtoOSaCoNJi-NH N*N-*OaOOCC0OJ0 i0CO0J0N0 r-COtrO-ooe-Oh :; t . hc<-CcOoCCcJOotC'-CfJC^O* :;i * HC{N< 0OH0J ^CO(T0* c0T* eooceooocrco-jct^'>JiaH^*o CJC<C<C<C< C<CJC<C<C< l Compiled by W ..M . Sawdon, vapor pressures converted from International Critical Tables. *3 a 3 OCJ^OO*CODN"< O^<c^og0o0*CHJeCoD lCAJiCQ<iCOJlCQ<tCO< cCD<Cc<DCcJoCrJ-Cc>< rH-fo-cooonoo ifl ifliO oo OOOtOPCOJOICDJCO* OOC'*J0t*0CC<-CO co<o>*<D 0e5ort-<- i-H'*clOooAoC-<Oeto- j 0cj0c<c<c<e< , oCO dCO oCOdCOdCO CO CO CO CO CO cCOicCjOcCjeO oCOeCoO :: Dry Air 0F Datum 27.60 27.84 28.08 28.32 28.56 1 Vapor 32 F Datum Dry Air with Vapor to Saturate it 1108.5 1106.9 1107.4 1107.8 , 1108.3 1108.7 1109.2 1109.6 1110.1 1110.5 80.93 83.00 85.13 87.30 89.54 91.86 94.21 96.70 99.20 101.76 1111.0 . 1111.4 1111.9 1112.3 1112.8 104.40 107.13 109.92 112.85 115,80 1113.2 1113.7 1114.1 1114.6 1115.0 1 1 118.89 122.01 125 .-27 128.63 132.06 1115.5 1115.9 1116.4 1116.8 1117.3 135.59 139.26 143.01 146.87 150.96 1117.7 1118.2, . 1118.6 . 1119.1 1119.5 . 154.93 159.26. 163.68 168.24 172.89 1120.0 1120.4 1120.9 1121.3 1121.8 177.67 182.67 187.80 193.14 198.61 , . tfitbr-oo : Whh5h{ T American Society, of Heating and Ventilating Engineers Guide, 1936 a ss g ll i r w*r-Mr NCO2t#!< tfieOD' wf-00 HWCO^f w")cor-coo OfCJCOCOt to r- ooa *- M CO Tf ' 18 T a b l e 5. P r o p e r t ie s o f Sa t u r a t e d W a t e r V a p o r w it h A ir , 0 F t o 200 Fa (C o n t in u e d ) .<is Q w o 2 a e ds oh S 6 & IVolume in Co Ft Barometer, 29.92 n. Hq In. of Hg Lb per Sq In. ; j Founds 1 Grains -9 u & Grains of 1 lb of Dry Air O CO to 00 o MMiMflOOJOCOO MCO etoo oeoo ov c^o m*< 0V0 O CO CD CtoO to to to to to U0 tO tO to to ' tOtOtO 5.8779 6.0306 6.1874 6.3482 6.5111 ! 2.887 2.962 3.039 3.118 3.198 0.008116 .008313 .008516 .008724 .008933 50.81 58.19 59.61 61.07 | 62.53 0.1521 .1570 .1622 .1675 .1730 1064.7 1099.0 1135.4 1172.5 1211.0 j -? 'O00COCOM5 MOO CO COCO COCO 0.6781 0.8471 7.0222 7.1993 7.3805 0.009148 .009366 .009590 .009817 .010040 64.04 65.56 67.13 68.72 70.28 0.1787 .1846 .1908 .1971 .2037 1250.9 1292.2 1335.6 1379.7 1425.9 ! 7.5058 7.7551 7.9485 8.1460 8.3476 3.716 3.809 3.904 4.001 4.100 0.010284 .010526 .010772 ' , .011022 .011279 71.99 73.68 75.40 77.15 78.95 0.2105 .2170 .2250 .2327 .2407 1473.5 1523.2 1575.0 1628.9 1684.9 8.5532 8.7650 8.9788 9.1986 9.4208 4.201 4.305 4.410 4.518 4.627 0.011539 .011807 .012077 .012354 .012634 80.77 82.65 84.54 86.48 88.44 i c^otrt'ao-cr<.o^oc-ro-oowooo MMMMM o 1743.0 1803.9 1866.9 1932.7 2000.6 9.6486 9.8807 10.119 10.301 10.008 eo NcoClOOO0O0W 0.012919 .013211 ` .013509 .013812 .014120 90.43 92.48 94.50 96.68 98.84 rtOeoo- c-eHo-cwoo --co 2072.7 2140.9 ! 2225.3 ' 2306.5 2391.2 ic--oi m 10.860 11.117 . 11.379 - 11.646 11.919 i *5.334 5.460 5.589 5.720 5.854 0.014434 .014753 . .015080 .015410 .015750 CO CO -H coo Oto rO-h 0.3544 .3677 .3817 .3964 .4118 1- 2480.8 2573.9 2671.9 2774.8 2882.6 . 12.196 l 5.090 12.480 0.130 12.770 6.272 13.065 0.417 13.366. 0.505 0.016092 1 | v .016444 .016801 .017164 .017534 112.6 115.1 117.0 120.1 122.7 0.4280 .4451 .4631 .4821 .5022 ; 2996.0 3115.7 3241.7 3374.7 3515.4 A " Compiled by W . M.'Sawdon? rapor pressures converted from International C ritical Tables. 15.01 15.03 15.06 15.68 15.71 cro- r- or-o tc-o* ecoo ooCoOo-oi CO WO to to to to of 1 lb Dry Air o+f Vapor to Saturate it 1 1 ! 18.79 18.94 19.10 19.26 19.43 19.60 19.78 19.96 20.15 20.35 ttoOcto-Or-SMco^ MMoMM-*M^ 21.07 21.93 22.19 22.46 22.74 CoO CcoO m oo CcoO Meo MeoMeoMeoM^ 24.69 25.07 1 25.46 25.88 26.31 20.77 ! 27.24 27.74 28.28 28.84 1 ! i j Dry Air OF Datum 33.01 33.85 34.09 34.33 34.57 34.81 35.05 35.29 35.53 35.77 38.43 38.07 38.91 39.15 39.39 39.63 39.87 40.11 40.35 40.59 40.83 41.07 41.32 41.56 41.80 3 aOm E O O 5 w MOCNOIOQ'ON'OOO) MM CD Of- 0r*0 tCoO CCOO CCOO CCOD CeOo CNONCOSCNO CCO OCO Vapor 32 F Datum 1 1122.2 1122.7 1123.1 1123.6 1124.0 1124.5 1124.9 1125.4 1125.8 1126.3 1126.7 1127.2 1127.6 1128.1 1128.5 1129.0 1129.4 1129.9 1130.3 1130.8 1131.2 1131.7 1132.1 1132.5 1133.0 1133.5 1133.9 1134.4 1134.8 1135.3 1135.7 1136.2 1136.6 1137.1 1137.5 Dry Air with Vapor to Saturate H 204.30 210.11 ' 210.20 222.53 , 220.02 235.70 242.71 250.02 257.43 265.20 273.19 281.54 1 ! 290.21 299.25 I 308.61 318.34 328.51 339.04 | 350.02 361.36 373.38 385.76 398.80 412.34 426.42 441.34 456.81 473.11 490.18 508.11 526.91 646.79 507.68 589.76 613.05 T a b l e 5. Pr o p e r tie s of Sa t u r a t e d W a t e r V apor w it h A ir , 0 F to 200 Fa (C o n c lu d e d ) Chapter 1- Fundamentals of Heating and Air Conditioning of andAmerican Society Heating Ventilating Engineers Guide, 1936 dt, the weight of saturated vapor mixed with 1 lb of dry air, Wt, (at a relative humidity of 100 per cent and a barometric pressure, B, of 29.92 in. of mercury), the specific volume of dry air, and the volume of an air-vapor mixture containing 1 lb of dry air (at a relative humidity of 100 per cent and a pressure of 29.92 in. of mercury). The preceding equations or the data from Table 5 may be conveniently used in solving the following typical problems: Example 2. Humidifying and Heating. Air is to be maintained at 70 F with a relative humidity of 40 per cent (4> = 0.4) when the outside air is at 0 F and 70 per cent relative humidity (<1> = 0.7) and a barometric pressure, B, of 29.92 in. of mercury. Find the weight of water vapor added to each pound of dry air and the dew-point temperature of the humidified air. Solution. From Equation 5a and Table 5, Wi = 0.622 ( gg 92^_?`00264 ) = 0-000548 lb per pound of dry air. Wt = 0.622 ( 29^)2^--* 0^2()5 ) = 0.00618 Ib per pound of dry air. The water vapor added per pound of dry air must be (Wt -- W,) or 0.005632 lb. By inspection of Table 5, Wt = 0.00618 at* 44.5 F, so this is the dew-point temperature of the humidified air. .' 1 An approximation of the same result from Table 5 is W\ -- 0.7 X0.0007852 = 0.00054964 lb per pound of dry air. W -- 0.4 X 0.01574 = 0.006296 lb per pound of dry air. The water vapor added per pound of dry air is approximately 0.00574636 lb and the dew-point temperature is approximately 45 F. The degree of approximation is evident. Example S. Dehumidifying and Cooling. Air with a dry-bulb temperature of 84 F, a wet-bulb of 70 F, or a relative humidity of 50 per cent (<P -- 0.5), and a barometric pressure, B, of 29.92 in. of mercury is to be cooled to 54 F. Find the dew-point tem perature of the entering air and the weight of vapor condensed per pound of dry air. . Solution. From Equation 5a and Table 5, . Wi = o.622 = 001248 lb Per pound of dry air- Wt = 0.622 (29 92-o^oor) = -00887 Ib Per pund f dry air- Since W, = Wt when t = 63.4 F, this is the dew-point temperature of the entering air. The weight of vapor condensed is (W, -- Wt) or 0.00361 lb per pound of dry air: An approximate result is Wi = 0.5 X 0.02543 = 0.012715 lb per pound of dry air. .. Wt = 1 X 0.008856 = 0.008856 lb per pound of dry air, since the exit air is saturated/ Since Wj Wt at / = 64 F, this is the dew-point temperature of the entering air.; The weight of vapor condensed is 0.003859 Ib per pound of dry air. The degree of approxi mation is again evident. M ADIABATIC SATURATION OF AIR The process of adiabatic saturation of air is df considerable importance^ in air conditioning. Suppose that 1 lb of dry air, initially unsaturated but' carrying W lb of Water vapor with a dry-bulb temperature, t, and a wet-; 20 -X Chapter 1--Fundamentals of Heating and Air Conditioning bulb temperature, t\ be made to pass through a tunnel containing an exposed water surface. Further assume the tunnel to He completely in^ sulated, thermally, so that the only heat transfer possible is that between' the air and water. As the air passes over the water surface, it will gradu ally pick up water vapor and will approach saturation at the initial wetbulb temperature of the air, if the water be supplied at this wet-bulb tem perature. During the process of adiabatic saturation, then, the dry-bulb temperature of the air drops to the wet-bulb temperature as a limit, the wet-bulb temperature remains substantially constant, and the weight of water vapor associated with each pound of dry air increases to Wv, as a limit, where Wt> is the weight of saturated vapor per pound of dry air for saturation at the wet-bulb temperature. ............. Example 4. If air with a dry-bulb of 85 F and a wet-bulb of 70 F be saturated adiabatically by spraying with recirculated water, what will be the final temperature and the vapor content of the air? Solution. The final temperature will be equal to the initial wet-bulb temperature or 70 F, and since the air is saturated at this temperature, from Table 5, W = 0.01574 lb per pound of dry air. In the adiabatic saturation process, since the heat given up by the dry air and associated vapor in cooling to the wet-bulb temperature is utilized in evaporation, of water at the wet-bulb temperature, W. H. Carrier has pointed out8 that the equation for the process of adiabatic saturation, and hence for a process of constant wet-bulb temperature, is: h\z (Wv -W)=c^(l- t') + cPsW (t - t') (9a) and using cPa = 0.24 and cP3 = 0.45 - where h'ig (Wv - W) = (0.24 + 0A5W) (t - <') ... (9b). h'te = latent heat of vaporization at t\ Btu per pound. . (Wt< -- W) = increase in vapor associated with 1 lb of dry air when it is saturated. adiabatically from an initial dry-bulb temperature, /, and an initial vapor content, W, pounds. . Knowing any two of the three primary variables, t, V, or W, the third may be found from this equation for any process of adiabatic saturation. TOTAL HEAT AND HEAT CONTENT The total heat of a mixture of dry air and water vapor was originally defined by W. H. Carrier as . ' where . 2 - - o) + w [A'fg + c,,8 - f)i . ....................... . : . : do) S total heat of the mixture, Btii per pound of dry air. ~ Cpa = mean specific heat at constant pressure of dry air. .. Cpg = mean specific heat at constant pressure of water vapor. .. t = dry-bulb temperature, degrees Fahrenheit. , . . t' = wet-bulb temperature, degrees Fahrenheit. !. .... .......... . ............... ,'A.S.M.E. Transactions, Vol. 33, 1911. p. 1005. 21 American Society of Heating and Ventilating Engineers Guide, 1936 W = weight of water vapor mixed with each pound of dry air, pounds. h'ig = latent heat of vaporization at /', Btu per pound. Since this definition holds for any mixture of dry air and water vapor, the total heat of a mixture with a relative humidity of 100 per cent and at a temperature equal to the wet-bulb temperature (/') is . S' = fpa (/' - 0) + WV h'is (ll) By equating Equation 10 to Equation 11, the equation for the adiabatic saturation process, Equation 9a, follows. This demonstrates that the adiabatic saturation process at constant wet-bulb temperature is also a process of constant total heat. In short, the total heat of a mixture of dry air and water vapor is the same for any two states of the mixture at the same wet-bulb temperature. This fact furnishes a convenient means of finding the total heat of an air-vapor mixture in any state. Example 5. Find the total heat of an air-vapor mixture having a dry-bulb tempera ture of 85 F and a wet-bulb temperature of 70 F. Solution. From Table 5, for saturation at the wet-bulb temperature Wt< = 0.01574, and from Equation 11, ' = CD* (70 - 0) + 0.01574 h'ig = 16.8 + 17.16 = 33.96 By considering the temperatures in Table 5 to be wet-bulb readings, the total heat of any air-vapor mixture may be obtained from the last column in the table. Enthalpy This total heat of an air-vapor mixture is not exactly equal to the true heat content or enthalpy of the mixture since the heat content of the liquid is not included in Equation 10. With the meaning of heat content in agreement with present practise in other branches of thermodynamics, the .true heat content of a mixture of dry air and water vapor (with 0 F as the datum for dry air, and the saturated liquid at 32 F as the datum for the water vapor) is where h = Clfe it - Q) + W hg = 0.24(/ - 0) -f- W ha h = the heat content of the mixture, Btu per pound of dry air. t = the dry-bulb temperature, degrees Fahrenheit. W the weight of vapor per pound of dry air, pounds. As = the heat content of the vapor in the mixture, Btu per pound. (12) . The heat content of the water vapor in the mixture may be found in steam charts or tables when the dry-bulb temperature and the partial pressure of the vapor are known. Or, since the heat content of steam at low partial pressures, whether super-heated or saturated, depends only upon temperature, the following empirical equation, derived from Keenan's Steam Tables, may be used: As = 1059.2 + 0.451 ' (13) Substituting this value of ks in Equation 12, the heat content of the mixture is . .. 22 Chapter 1 Fundamentals of Heating and Air Conditioning A = 0.24 (/ -- 0) + W (1059.2 + 0.45 t) . (14) An energy equation can be written that applies, in general, to various air-conditioning processes, and this equation can be used to determine the quantity of heat transferred during such processes. In the most general form, this equation may be explained with the aid of Fig. 1 as follows: The rectangle may represent any apparatus, e.g.; a drier, humidifier, dehumidifier, cooling tower, or the like, by proper choice of the direction of the arrows. In general, a mixture of air and water vapor, such as atmospheric air, enters the apparatus at 1 and leaves at 3. Water is supplied at some temperature, /,. For the flow of 1 lb of dry air (with accompanying vapor) through the apparatus, provided there is no appreciable change in the elevation or velocity of the fluids and no mechanical energy delivered to or by the apparatus, . A. + Eh + (W, - W0 A, = A, + Rc or h - Ec = A, - A, - {W, - Wi) A, (15) where Eb = the quantity of heat supplied per pound of dry air, Btu. Ec = the quantity of heat lost externally by heat transfer from the apparatus, Btu per pound of dry air. Wi = the weight of water vapor entering, per pound of dry air. . W, = the weight of water vapor leaving, per pound of dry air. Aj = the heat content of the water supplied at t>, Btu per pound. fit -- = the increase in the heat content of the air-water vapor mixture in passing through the apparatus, Btu per pound of dry air = 0.24 (Is - l,) + W, (1059.2 + 0.45 It) - W, (1059.2 + 0.45/,) The net quantity of heat added to or removed from air-water vapor mixtures in air conditioning work is frequently approximated by taldng the differences in total heat at exit and entrance. . For example, in Fig. 1, an approximate result is where Eh - Ec = S, - 2, (16) . Bs = the total heat of the air-vapor mixture at exit, Btu per pound of dry air. S, = the total heat of the air-vapor mixture at entrance, Btu per pound of dry air. From the definitions of total heat and heat content, it may be demon strated that Equation 16 is exactly equivalent to Equation 15, when, and only when, t\ = t\ = k; i.e., when the initial and final wet-bulb tempera tures and the temperature of the water supplied are equal. The one pro- . cess that meets these conditions is adiabatic saturation, and either equation will give a result of zero; for other conditions, Equation 16 is approximate but satisfactory for many calculations. The following problems illustrate the application of these principles: Example 6. Heating (data from Example 2). Assuming the water to be supplied at 50 F, the net quantity of heat supplied is, from Equation 15, Eh - Ec = 0.24 (70 - 0) + 0.000548 X 0.45 (70 - 0) + 0.005632 , [1059.2 + 0.45 X 70 -- (50 -- 32)] = 22.90 Btu per pound of dry air. 23 American Society of Heating and Ventilating Engineers Guide, 1936 'Example 7. Cooling (data from Example 3)- If-the condensate is removed at 54 F the quantity of heat removed is found from Equation 15, by proper regard to the arrow direction in Fig. 1, . . ,; ................. Eh + Rc = 0.24 (84 - 54) + 0.00887 X 0.45 (84 - 54) + 0.00361 [1059,2 -j- 0.45 X 84 -- (54 -- 32)1 = 11.24 Btu per pound of dry air. Using Table 5, the initial total heat of the air-vapor mixture, since the wet-bulb temperature is 70 F, is 33.96 Btu per pound of dry air. The final total heat is, from Table 5, since the exit air is saturated, 22.55 Btu per pound. Hence, using Equation 16, the quantity of heat removed is, approximatefy, (33.96 -- 22.55) or 11.41 Btu per pound of dry air. The degree of approximation to the correct result is evident in this example. . PSYCII IlOMETRIC CHART4 The revised Bulkeley Psychrometric Chart5, will-be found attached to the inside back cover. It shows graphically the relationships expressed in Equations 9a and 9b. It also gives the grains of moisture per pound of dry air for saturation, the grains of moisture per. cubic foot of saturated air, the total heat in Btu per pound of dry air saturated with moisture, and the weight of the dry air in pounds per cubic foot. Fig. 2 shows the procedure to follow in using the Bulkeley Chart. The directrix curves above the saturation line are as follows: ' 4 "is the total heat in Btu contained in the mixture above 0 F, and is to be referred to the column of figures at the left side of the chart. Heat of the liquid is not included. B is the pains of moisture of water vapor contained in each pound of the saturated mixture and is to be referred to the figures at the left side of the chart. . Cis the grains of moisture of water vapor per cubic foot of saturated mixture, and is to be referred to the figures at the left side of the chart which are to be divided by 10. rD is the. weight in decimal fractions of a pound, of one cubic foot of the saturated mixture, and is referred to the first column of figures to the right of the saturation Jine between the vertical dry-bulb temperature lines 170 and 180 F; The relative density of the mixture is read in a similar manner from the same curve by the column of figures between the vertical dry-bulb temperature lines 180 and 190 F. ., E is similar to D but is for dry air, devoid of all moisture or water vapor. For.con- ' *See A Review of Psychrometric Charts. C. O. Mackey. {Heating and VentUeling, June, July, 1931), The Bulkeley Psychrometric Chart was presented to the Society in 1926. (See A.SIH.V.E. Thaws- actions, Vol. 32, 1926.) Single copy of the chart can be furnished at a cost of $ .50. . , ' Chapter 1--Fundamentals of Heating and Air Conditioning venience, the approximate absolute temperature Of 500 F is given at 40F on the satura tion line for the purpose of calculating volume, weight per cubic foot, and relative density at partial saturation. , METHOD OF USING THE CHART Example 8. Relative Humidity: At the intersection of the 78 F wet-bulb line and the 95 F dry-bulb line, the relative humidity is read directly on the straight diagonal lines as 46 per cent. .: Example 9. Dew Point: At the intersection of the 78 F wet-bulb line, the dew-point temperature is read directly on the horizontal temperature lines as 70.9 F. A-frC*D DirecWx Line* D.ELL'Orjf fcrfbUne D.P.L." Dew WntLine 6.P.LB4*6reim ItashmperLbJby AirSaturated T.H.STotal Heat per Lb.Drt AirSaturated \P.\tawrPressure in MmJAerowr . .. 6J,.C-fii.*6rains MoisturaperCb.Ff.SgturcrtcdAtr ftJt.L.=Relative Humidity Line WB1.* WetBufb Line .. S.L. * Saturation Line EP.C/.isKpght perCu/t.in Lbs.Saturated RD.S.*ReIatwe density perCu.Ff.Safunrterf lP.CfJ).*Rdlative DensityperCu.ft.0r* R.0.0.*Rdative DensityperGuJt.Qry 6.RCJ. i6.P.C.F.at Partial Saturation Abs.Temp.at OB. "KL AbsJmavflXR, Abs.Tmp.(rtD.h. W.P.CF. at Partial Saturation Abs-Tcmp. of P.P., R.O. at Partial Saturation ' * /U&Temp. at 0-6. o nmnDAuc QurkTOiMr: PuommTOR to FoT.r.ow in Using Bulkeley Chart Example 10. Vapor Pressure: At the intersection of the 78 F wet-bulb line and the 95 F dry-bulb line, pass in a horizontal direction to the left of the chart and on the logarithmic scale read the vapor pressure as 19.4 millimeters of. mercury. (Divide by 25.4 for inches.) Example 11. Total Heat Above 0 F in Mixture per Pound of Dry Air Saturated with Moisture: From where the wet-bulb line joins the saturation line, pass in a. vertical direction on the 78 F dry-bulb line to its intersection with curve A and on the logarithmic scale at the left of the chart read 40.6 Btu per pound of mixture. The use of this curve to obtain the total heat in the mixture at any wet-bulb temperature -is a great con venience, as the number of Btu required to heat the mixture and humidify it, as well as the refrigeration required to cool and dehumidify the mixture, can be obtained by taking the difference in total heat before and after treatment of the mixture. Example IS. Grains of Moisture per Pound of Mixture: From 70.9 F dew-point temperature on the saturation line, pass vertically to the intersection with curve B and on the logarithmic scale at the left read 114 grains of moisture per pound. ' Example 18 Grains of Moisture per Cubic Foot of Mixture, Partially Saturated: From 70.9 F dew-point temperature on the saturation line proceed in a vertical direction to curve C, and on the logarithmic scale to the left read 83.3 which, divided, by 10, gives. 8.33 grains. A temperature of 70.9 F is equal to an absolute temperature of 530.9, and - 95 F equals -555, absolute temperature.' Therefore, .^: X 8.33 = 7.97 grains per cubic foot of partially saturated mixture. - . Example 14. Grains of Moisture per Cubic Foot of Dry Air, Saturated: Starting at the saturation line at the desired temperature, pass in a vertical direction to curve C and on. 25 . $. of and 1936American Society Heating Ventilating Engineers Guide, the logarithmic scale at the left, read a number which, divided by 10, will give the answer. Example 16. Weight per Cubic Foot of Dry Air and Relative Density: From the point where, for example, the 70 F vertical dry-bulb line intersects curve E, pass to right side and read 0.075 lb; if cubic feet per pound are desired, divide 1 by this amount. The relative density is read immediately to the right as 1.00. ' Example 16. Weight per Cubic Fool of Saturated Air and Relative Density: From the point where, for example, the 70 F vertical line intersects the curve D, pass to the right and read weight per cubic foot as 0.07316 with a relative density of 0.9755 for saturated air at 70 F. Example 17. Weight per Cubic Foot and Relative Density of Partially Saturated Air- j . . an<? a wet-bulb temperature of 46 F is to be heated to 130 F. The wet- and dry-bulb lines intersect at a dew-point temperature of 42 F. Pass to the left where this dew-point line intersects the saturation line and then pass in a vertical direction to where the 42 F dry-bulb line intersects with curve D. Then pass directly to the right and read i P*'1! cubic foot of saturated air at 42 F as 0.07844 and the relative density as T046. The absolute temperature at 42 F is 502, and at. 130 F is 590. Therefore, 590 = 0.851. The weight of 1 cu ft of air at 50 F dry-bulb and 46 F wet-bulb when ^ *s 0-07844 X 0.851 = 0.06675, and the relative density is 1.046 X 0.851 PROPERTIES OF STEAM Steam is water vapor which exists in the vaporous condition because sufficient heat has been added to the water to supply the latent heat of evaporation and change the liquid into vapor. This change in state takes place at a definite and constant temperature which is determined solely by the pressure of the steam. The volume of a pound of steam is the specific volume which decreases as the pressure increases. The reciprocal of this, or the weight of steam per cubic foot, is the density. (See Table 6.) Steam which is.in.contact with the water from.which it-was.generated is known as saturated steam. If it contains no actual water in the form of mist or priming, it is called dry saturated steam. If this be heated and the pressure maintained the same as when it was vaporized, its temperature will increase and it will become superheated, that is, its temperature will be higher than that of saturated steam at the same pressure. PROPERTIES OF WATER Composition of Water. Water is a chemical compound (HsO) formed by the union of two volumes of hydrogen and one volume of oxygen, or two parts by weight of hydrogen and 16 parts by weight of oxygen. ' Density of Water. Water has its greatest density at 39.2 F, and it expands when heated or cooled from this temperature. At 62 F a U. S. gallon of 231 cu in. of water weighs approximately 8% lb, and a cubic foot of water is equal to 7.48 gal. The specific volume of water depends on the temperature and it is always the reciprocal of its density., (See Table 7.) Water Pressures. Pressures are often stated in feet or inches of water column. At 62 F, with h equal to the head in feet, the pressure of a column of water is 62.383/; lb per square foot, or 0.433/; lb per square inch. A column of water 2.309 ft (27.71 in.) high exerts a pressure of one pound, per square inch at 62 F. Boiling Point of Water. The boiling point of water varies with the pressure; it is lower at higher altitudes. A change in pressure will always 26 ' Chapter 1--Fundamentals of Heating and Air Conditioning- Table 6. Properties of Saturated Steam: Pressure Table* ALbb.*/S. qP<r**l*a<,. Tamp. Da*. F. pt W'Bg 58.83 %"H* 70.44 l"Hg 79.06 lV4"Hg 91.75 s Hi 101.17 l-S 108.73 115.08 Specific Volume Sat. Sat. Liquid Enp. Vapor VI Tt 0.01603 1256.9 0.01605 856.5 0.01607 652.7 0.01610 4454 0.01613 339.S 0.01616 2754 0.01618 2314 v* 1256.9 8564 6527 4454 3394 2754 8314 Total Heat Sat. Liquid hr 264838.47 47.06 59.72 69.10 7643 82.96 Enp, hr* 1058.8 1052.5 1047.8 10404 1035.7 10314 1027.9 Sat. Vapor hg 10857 1091.0 1094.9 1100.6 1104.8 1108.1 11104 Entropy Sat. Liquid Evap. Sat. Ah*. Pttu. Vapor Lb./3q. In. Sf sr Sg P 04533 2.0422 2.0955 0.0754 1.9856 0.0914 1.9451 0.1147 13877 0.1316 .13468 0.1450 1.8148 0.1561 1.7885 2.0609 2.0365 2.0024 1.9784 1.9598 1.9446 W'Bg 1"Hg 1%"H* a" hg *W*Bg 3"Hg 1.0 101.76 2.0 126.10 3.0 141.49 4.0 152.99 6.0 16245 6.0 170.07 7.0 176.85 8.0 18247 9.0 188.28 10.0 11.0 12.0 13.0 14.0 14.696 19341 197.75 201.96 205.88 209.56 212.00 16.0 18.0 20.0 22.0 24.0 26.0 28.0 21642 222.40 227.96 233.07 23742 24245 246.41 0.01614 333.8 333.9 0.01623 173.94 173.96 0.01630 11844 11846 0.01636 90.72 9074 0.01641 0.01645 0.01649 0.01652 0.01*656 73.59 62.03 53.68 4748 42.42 73.61 62.05 5370 4749 42.44 0.01658 0.01661 0.01664 0.01666 0.01669 0.01670 38.44 35.15 32.40 30.06 28.05 2640 38.45 35.17 32142 30.08 28.06 26.82 0.01673 0.01678 0.01682 0.02685 0.01689 0.01692 0.01695 24.75 2476 22.16 22.18 20.078 20.095 18463 18480 16.924 16.941 15.701 15718 14.647 14464 69.69 ,10354 1105.0 93.97 1021.6 1115.6 10943 1012.7 1122.0 12043 1005.9 1126.8 130.10 137.92 14471 150.75 156.19 1000.4 995.8 9917 988.1 9844 1130.6 11337 1136.4 1138.9 U4LQ 161.13 165.68 169.91 17341$ 17745 180.00 981.8 979.1 976.5 974.1 971.8 9704 1143.0 11444 1146.4 1147.9 11494 11504 18445 190.48 196.09 20145 206.05 21044 21475 967.4 963.5 959.9 956.6 9S3.4 950.4 947.7 11514 1154.0 1156.0 11574 11594 1161.0 1162.4 0.1326 0.1750 0.2009 0.2198 04348 04473 04580 04674 0.2758 04834 04903 04968 04027 04082 04119 04184 04274 03356 04431 04500 04564 04624 1.8442 1.9769 1.7442 1.9192 1.6847 13856 1.6420 13618 1.6088 1.5814 2.5582 1.5379 1.5200 13435 13287 13262 13053 1.79S8 1.5040 1.4894 1.4760 1.4636 1.4521 1.4446 1.7874 1.7797 1.7727 1.7663 1.7604 1.7564 1.4312 1.7496 1.4127 1.7402 13960 1.7317 13809 1.7240 13670 1.7170 13542 1.7106 13422 . 1.7046 1.0 2.0 3.0 . 4.0 6.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 13.0 14.0 14.696 16.0 18.0 20.0 22.0 .24.0 26.0 28.0 30.0 32.0 84.0 86.0 38.0 2S044 254.05 25748 260.94 264.16 0.01698 0.01701 0.01704 0.01707 0.01710 13.728 12.923 12409 11.570 10.998 13.745 12.940 12426 11487 11.015 21873 222.50 226.09 22941 23279 945.0 942.5 940.0 937.7 935.5 1163.7 1165.0 1166.1 11674 U6S4 04680 04732 04783 04830 04876 13310 13206 13107 13014 1.2925 1.6990 1.6938 1.6890 1.6844 1.6800 30.0 32.0 34.0 36.0 38.0 40.0 42.0 44.0 46.0 48.0 26744 27041 273.06 27541 278.45 0.01712 0.0171S 0.01717 0.01719 0.01722 10.480 10.010 9.582 9.189 8429 10.497 10.027 9499 9407 8446 235.93 238.95 441.86 244.67 24747 9334 931.2 929.2 9274 925.4 1169.2 11704 1171.1 1171.9 1172.7 04919 04961 0.4000 0.4039 0.4076 13840 13759 13682 13608 13537 1.6759 1.6720 1.6683 1.6647 13613 40.0 42.0 44.0 46.0 48.0 60.0 62.0 64.0 66.0 68.0 281.01 283.49 285.90 28843 290.S0 0.01724 0.01726 0.01728 0.01730 0.01732 8.496 8.189 7.902 7.636 7488 8414 8406 7.919 7.653 7.405 249.98 25242 2S4.99 25748 25971 923.5 .11734 921.7 11744 920.0 1175.0 9184 11757 916.6 1176.4 0.4111 0.414S 0.4178 0.4210 0.4241 13469 13404 13340 13279 13220 1.6580 1.6549 1.6518 1.6489 1.6461 60.0 62.0 54.0 66.0 68.0 60.0 62.0 64.0 66.0 68.0 292.71 29445 296.94 298.98 300.98 0.01735 0.01737 0.01739 0.01741 0.01743 7.155 6.937 6.732 6.539 64S7 7.172 6.955 6749 6456 6475 261.98 46478 26643 268.43 270.49 915.0 913.4 911.9 910.4 908.9 1177.0 1177.6 11784 11784 1179.4 0.4271 13162 0.4300 13107 0.4329 13053 0.4356 .13001 0.4384 1.19SO 1.6434 1.6407 1.6382 1.6357 1.6333 - 60.0 62.0 64.0 66.0 68.0 70.0' 72.0 74.0 76.0 78.0 302.92 30442 306.68 30840 31048 0.01744 0.01746 0.01748' 0.01750 0.01752 6.186 6.024 5470 5.723 5484 6403 6.041 5487 5.741 5.602 272.49 .274.45 27647 27845 280.09 907.4 1179.9 906.0 1180.5 904.6 1181.0 9034 -11814 901.9 1182.0 0.4410 >0.4435 0.4460 0.4485 0.4S09 1.1900 1.1852 1.1805 1.1759 1.1714 1.6310 1.6287 1.6265 1.6244 1.6223 70.0 72.0 74.0 76.0 78.0 80.0 82.0 84.0 86.0 88.0 312.03 313.74 31S.42 317.06 318.68 0.01754 0.01756 0.01757 0.01759 0.01761 5.4S2 5425 5404 5489 41979 5.470 281.90 5443 . 283.67 5422 285.42 5.107 287.13 4.997 28840 9004 8994 897.9 8967 895.4 1182.4 1182.9 1183.4 11834 11844 * 0.4532 0.4555 0.4578 0.4599 0.4621 1.1670 1.1627 1.1586 1-1545 1.1505 13202 13182 13163 13144 1.6126 80.0 82.0 84.0 86.0 88.0 90.0 92.0 94.0 96.0 88.0 32047 32143 . 32347 , 324. 32647 0.01763 0.01764 0.01766 0.01768 041769 4474 4.773 4.676 4.584 4.494 4492 4.791 '4.694 4.602 4412 290.45 292.07 29347 49545 '796.80 8944 11844 893.0 .1185.0 891.8 1185*4 .890.6 11854 889.4 11864 0.4642 0.4663 0.4683 0.4703 0.4723 1-1465 1.6107 1.1427 1.6090 1-1389 13072 1.1352 1.6055 1.1316 .13038 60.0 92.0 94.0 96.0 83.0 .Abstracted from Steam Tables and Mdlier Diagram, by Prof. J. H. Keenan, 1930 edition, by permission of the publisher. The American Society of Mechanical Engineers. ' ' 27 American Society of Heating and Ventilating Engineers Guide, 1936 Table 6. Properties of Saturated Steam: Pressure Table--(Continued) Aba. Pm*. Lb./Sq. In. P 100.0 102.0 104.0 106.0 108.0 Temp. Def. F. t 327.83 329.27 330.68 332.08 333.44 110.0 112.0 114.0 116.0 118.0 334.79 336.12 337.43 338.72 340.01 120.0 122.0 124.0 126.0 128.0 341.26 342.50 343.73 344.94 346.14 180.0 132.0 134.0 136.0 138.0 347.31 348.48 349.64 350.78 351.91 140.0 142.0 144.0 146.0 148.0 353.03 354.14 355.22 356.31 35737 160.0 162.0 164.0 166.0 168.0 358.43 359.47 360.51 361.53 362.54 160.0 162.0 164.0 166.0 168.0 363.55 364.54 365.52 366.50 367.46 170.0 172.0 174.0 176.0 178.0 368.42 36937 37031 371.24 372.16 180.0 182.0 184.0 186.0 188.0 373.08 374.00 374.90 375.78 -376.67 190.0 192.0 194.0 196.0 198.0 377.55 378.42 379.27 380.13 380.97 200.0 206.0 ' 210.0 216.0 220.0 381.82 383.89 385.93 387.93 389.89 226.0 230.0 , 236.0 240.0 246.0 391.81 393.70 395.56 397.40 39920 Specific Volume Sat. Sat. Liquid Evap. Vapor VI Vfg v 0.01771 0.01773 0.01774 0.01776 0.01777 4.408 4.326 4247 4.171 4.097 4.426 4344 4.265 4.189 4.115 0.01779 4.026 4.044 0.01780 3.958 3.976 0.01782 3.892 3.910 0.01783 3.828 3.846 0.01785 3.766 3.784 0.01786 3.707 0.01788 3.652 0.01789 3.597 0.01791 3.542 0.01792 .3.487 3.725 3.670 3.615 3.560 3.505 0.01794 3.433 0.01795 3.383 0.01796 3.335 0.01798 3.288 0.01799 3.242 3.451 3.401 3353 3306 3360 0.01801 3.198 0.01802 3.155 0.01804 3.112 0.01805 3.071 0.01806 3.031 3.216 3.173 3.130 3.089 3.049 0.01808 2.992 0.01809 2.954 0.01810 2.917 0.01812 2.882 0.01813 2.846 3.010 2.972 2.935 2.900 2364 0.01814 2.812 2.830 0.01816 2.779 2.797 0.01817 2.746 2.764 0.01818 2.715 2.733 0.01819 2.683 2.701 0.01821 2.653 0.01822 2.623 0.01823 2.594 0.01825 2.566 0.01826 2.538 2.671 2.641 2.612 2.584 2.556 0.01827 2.511 0.01828 2.484 0.01829 2.458 0.01831 2.433 0.01832 2.407 2.529 2.502 2.476 2.451 2.425 0.01833 2.383 2.401 0.01834 2359 2377 0.01835 2335 2353 0101837 2312' 2330 0.01838 2389 2307 0.01839 2.267 0.01842 2.213 0.01844 2.162 0.01847 2.113 0.01850 2.066 2.285 2.231 2.180 2.131 2.084 0.02853 2.0208 2.0393 0.01856 1.9778 1.9964 0.01859 1.9367 1.9553 0.01861 13970 1.9156 0.01864 1.8589 1.8775 Total Heat Sat. Sat. Liquid Evap. Vapor hf hfg . hg 29833 888.2 1186.6 299.83 887.1 1186.9 30130 886.0 11873 302.76 884.9 1187.6 304.19 883.8 1188.0 Entropy - Sat. Sat. Liquid Evap. Vapor 81 0.4742 0.4761 0.4779 0.4798 0.4816 S(g 1.1280 1.1245 1.1211 1.1177 1.1144 Sff 1.6022 1.6006 2.5990 1.5974 1.5959 Aba. Press.. Lb./Sq. In. P 100.0 102.0 104.0 106.0 108.0 305.61 882.7 11883 307.00 881.6 1188.6 30836 880.6 1188.9 309.71 879.5 11893 311.05 878.5 1189.5 0.4834 1.1111 1.5944 0.4851 1.1079 13930 0.4868 1.1048 13915 0.4885 1.1017 13901 0.4901 1.0986 13887 110.0 112.0 114.0 116.0 118.0 31237 877.4 1189.8 313.67 876.4 1190.1 314.96 875.4 1190.4 316.23 874.4 1190.6 317.49 873.4 1190.9 . 0.4918 1.0956 13874 0.4934 1.0926 13860 0.4950 1.0897 13847 0.4965 1.0868 13834 0.4981 1.0840 13821 120.0 122.0 124.0 126.0 128.0 318)73 872.4 11913 319.95 871.5 1191.4 321.17 870.5 1191.7 32237 869.6 1191.9 323.56 868.6 11923 0.4996 1.0812 13808 0.5011 1.0784 13796 0.5026 1.0757 13783 0.5041 1.0730 13771 0.5056 1.0703 1.5759 130.0 132.0 134.0 136.0 138.0 324.74 867.7 1192.4 325.91 .866.7 1192.6 327.06 865.8 1192.9 32830 864.9 1193.1 32932 864.0 11933 0.5070 1.0677 13747 .0.5084 1.0651 1.5735 0.5098- 1.0625 13724 0.5112 1.0600 13712 0.5126 1.0575 13701 140.0 142.0 144.0 146.0 148.0 330.44 863.1 1193.5 331.54 8622 1193.7 332.64 8613 1193.9 333.72 860.4 1194.1 334.80 859.5 11943 0.5140 1.0550 13690 0.51S3 1.0526 13679 0.5166 1)0502 13668 * 0.5180 1.0478 1.5658 0.5193 1.0454 13647 160.0 162.0 164.0 166.0 168.0 335.86 858.7 1194.5 336.91 857.8 1194.7 337.95 857.0 1194.9 338.99 856.1 1195.1 340.01 855.2 11953 0;520S 1.0431 1.5636 : 0.5218 1.0408 . 13626 0.5230 1.0385 13616 . 03243 1.0363 13606 0.5255 1,0340 .13596 160.0 162.0 . 164.0 166.0 168.0 341.03 .854.4 1195.4 342.04 853.6 1195.6 343.04 852.7 1195.8 344.03 851.9 1196.0 345.01 851.1 1196.1 0.5268 0.5280 0.5292 0.5304 0.5315 1.0318 1,0296 1.0275 1.0253 1<)232 1.5586 1.5576 1.5566 13557 1.5548 170.0 172.0 174.0 176.0 178.0 345.99 8503 11963 346.97 849.5 1196.4 347.94 848.6 1196.6 348.89 847.9 1196.8 349.8^. 847.1 1196.9 0.5327 1.0211 1.5538 0.5339 1.0190 13529 ; 0.5350- 1.0169 1.5520 . 0.5362 1.0149 1.5511 0:5373 1.0129 13502 180.0 182.0 184.0 186.0 188.0 350.77 8463 1197.0 . 351.70 845.5 11973 352.61 844.7 11973 353.53 844.0 1197.5 354.43 8433 1197.6 0.5384 1.0109 13493 0.539S -.1.0089 1.5484 03406 1.0070 1.5475 . 03417 1.0050 13467 0.S427 1.0031 13458 190.0 192.0 194.0 196.0 198.0 355.33 842.4 1197.8 357.56 840.5 1198.1 359.76 838.6 1198.4 361.91 836.8 1198.7 364.02 835.0 1199.0 0.5438 1.0012 1.54SO 03465 0.9964 13429 0.5491 0.9918 1.5409 03516 0.9873 1.5389 0.554Q 0.9829 1.5369 200.0 206.0 . 210.0 216.0 220.0 366.10 8332 11993 368.14 831.4 1199.6 370.15 829.7 1199.8 `372.13 827.9 1200.1 374.09 826.2 12003 0.5565 0.5588 03612 03635 0.5658 0.9786 0,9743 0.9702 0,9661 0.9620 1.5350 13332 13313 13295' 13278- 225.0 230.0 ' 235.0 240.0 245.0 ~ 28 Chapter. 1--Fundamentals of Heating and Air Conditioning Table 6. Properties of Saturated Steam: Pressure Table--(Continued) b. Press. b./Sq. In. p 260.0 260.0 27o!o 280.0 290.0 Temp* Deg. F. t 400.97 404.43 407.79 411.06 41424 Specific Volume Sat. Sat. Liquid Evap. Vapor Vf VfK v* 0.01867 1.8223 1.8410 0.01872 1.7536 1.7723 0.01877 1.6895 1.7083 0.01882 1.6302 1.6490 0.01887 13745 1.5934 300.0 320.0 340.0 360.0 980.0 41733 42339 428.96 43439 439.59 0.01892 1.5225 1.5414 0.01901 1.4279 1.4469 0.01910 13439 13630 0.01918 13689 1.2881 0.01927 13015 13208 400.0 44438 420.0 44938 440.0 454.01 460.0 458.48 480.0 . - 462.80 0.0194 0.0194 0.0195 0.01% 0.0197 1.1407 1.1601 1.0853 1.1047 1.0345 1.0540 0.9881 1.0077 ' 0.9456 0.9633 600.0 620.0 640.0 660.0 580.0 466.99 ' 0.0198 471.05 0.0198 474.99 0.0199 478.82 . 0.0200 48235 0.0201 0.9063 0.9261 0.8701 0.8899 0.8363 0.8562 0.8047 0.8247 0.7751 0.7952 600.0 620.0 640.0 660.0 680.0 486.17 489.71 493.16 496.53 499.82 0.0202 0.0202 0.0203 ' 0.0204 0.0205 0.7475 0.7677 0.7217 0.7419 0.6972 0.7175 0.6744 0.6948 0.6527 0.6732 700.0 720.0 740.0 760.0 780.0 S03.04 506.19 '509.28 51230 51537 0.0206 0.0206 0.0207 0.0208 0.0209 0.6321 0.6527 0.6128 0.6334 0.5944 0.6I5I 0.5769 0.5977 0.5602 0.5811 Total Heat Sat. Sat. Liquid Evap. Vapor hi hfg hg 376.02 824.5 1200.5 379.78 821.2 1201.0 383.44 818.0 1201.4 387.02 814.7 1201.8 390.50 811.6 1202.1 393.90 808.5 1202.4 400.47 8023 1203.0 406.75 7%.6 1203.4 412.80 790.9 1203.7 418.61 .7853 1203.9 4243 429.6 434.8 439.9 444.9 779.8 1204.i 774.5 1204.1 7693 1204.1 764.1 12040 7593) 1203.9 449.7 754.0 1203.7 454.4 749.0 1203.5 459.0 744.1 12033 463.6 7393 1202.9 468.0 ^ 734.5 1202.5 4723 476.6 480.8 484.9 488.9 729.8 1202.1 725.1 1201.7 720.5 12013 715.9 1200.8 7113 12003 492.9 496.8 500.6 504.4 5083 706.8 1199.7 702.4 11993 697.9. 1198.6 693.5 1198.0 6893 11974 Entropy Sat. Sat* ` Abe. Presi Liquid Evap. Vapor Lb./Sq. Ii 8f Sfg Sg P 0.5680 0.9581 1.5261 0.5723 0.9504 1.5227 260.0 260.0 0.S765 0.9430 1.5194 0.5805 0.9357 1.5163 0.5845 0.9287 1.5132 270.0 280.0 290.0 0.5883 0.5957 0.6027 0.6094 0.6157 0.9220 0.9089 0.8%5 0.8846 0.8733 1.5102 1.5046 1.4992 1.4940 1.4.891 300)0 320.0 340.0 360.0 . 380.0 0.6218 0.8625 1.4843 0.6277 0.8520 1.4798 0.6334 03420 1.4753 0.6388 03322 1.4711 0.6441 03228 1.4670 400.0 420.0 440.0 460.0 480.0 0.6493 0.8137 1.4630 0.6543 03048 1.4591 ' 0.6592 0.7%2 1.4554 0.6639 0.7878 1.4517 0.6686 0.7796 1.4482 600.0 620.0 640.0 660.0 680.0 0.6731 0.6775 0.6818 0.6861 0-6902 0.7716 0.7638 0.7562 0.7487 0.7414 1.4447 1.4413 1.4380 1.4348 1.4316 600.0 620.0 640.0 660.0 680.0 0.6943 0.7342 1.4285 0.6983 0.7272 1.4255 0.7022 0.7203 1.4225 0.7060 0.7136 1.41% 0.7098 0.7069 1.4167 700.0 720.0 740.0 760.0 780.0 800.0 820.0 840.0 860.0 880.0 518.18 521.03 523.83 526.58 529.29 0.0209 0.0210 0.0211 0.0212 0.0213 03444 0.5653 0.5293 0.5503 0.5149 0.5360 0.5013 0.5225 0.4881 0.5094 511.8 515.5 519.0 522.6 526.0 684.9 1196.7 680.6 1196.0 676.4 1195.4 672.1 1194.7 667.9 1194.0 0.7135 0.7004 1.4139 0.7171 0.6940 1.4111 0.7207 0.6877 1.4084 0.7242 0.6815 1.4057 0.7277 0.6754 1.4031 800.0 820.0 840.0 860.0 880.0 900.0 920.0 940.0 960)0 980.0 531.95 534.56 537.13 539.66 542.14 0.0213 0.0214 0.0215 0.0216 0.0217 0.4756 0.4969 0.4635 0.4849 0.4520 0.4735 0.4409 0.4625 0.4303 0.4520 529.5 532.9 5363 539.6 542.8 663.8 11933 659.7 1192.6 655.6 11913 6513 1191.1 6473 11903 0.7311 0.6694 1.4005 0.7344 0.6635 13980 0.7377 0.6577 13954 0.7410 0.6520 13930 0.7442 0.6464 13905 900.0 920.0 940.0 960.0 980.0 1000.0 1060.0 1100.0 1160.0 1200.0 54438 55033 55638 561.81 567.14 0.0217 0.0219 0.0222 0.0224 0.0226 0.4202 0.4419 03960 0.4179 03738 03960 03540 03764 03356 03582 546.0 554.0 561.7 5693 576.5 6433 1189.6 633.6 1187.6 623.9 1185.6 6143 1183.5 604.9 1181.4 0.7473 0.6408 13881 0.7550 0.6273 13822 0.7624 0.6141 13765 0.7695 0.6014 13709 0.7764 0.5891 13656 1000.0 1060.0 1100.0 1160.0 1200.0 1260.0 1300.0 1360.0 1400.0 1450.0 57230 57732 58231 586)96 591.58 0.0228 0.0230 0.0232 0.0235 0.0237 03187 03415 03029 0.3259 0.2884 03116 0.2748 03983 03621 03858 583.6 590.6 597.5 6043 611.0. 595.6 11793 5863 1177.0 5773 1174.7 568.1 1172.4 559.1. 1170.0 0.7831 0.5772 13603 0.7897- 0.5654 13552 0.7962 0.5540 13501 0.8024 03428 13452 0.8086 0.5318 13404 1260.0 1300.0 1360.0 1400.0 1460.0 1600.0 1600:0 1700.0 1800.0 1900.0 596.08 604.74 612.98 620.86 628.39 0.0239 0.0244 0.0249 0.0254 0.0260 03502 03741 03284 03528 03089 03338 0.1913 03167 0.1754 0.2014 617.5 6303 642.5 654.7 666.8 5503 1167.6 532.6 1162.7 515.0 1157.5 4973 1151)8 478.9 1145.7 0.8146 0.5212 13357 03262 0.5003 13265 0.8373 0.4801 13174 03482 0.4601 13083 03589 0.4402 13990 1600.0 1600.0 1700.0 1800.0 1900.0 2000.0 635.6 2200.0 649.2 2400.0 . 661.9 2600.0 673.8 2800.0 684.9 0.0265 0.0277 0.0292 . 0.0310 0.0333 0.1610 0.1875 0.1346 0.1623 0.1112 0.1404 0.0895 0.1205 0)0688 0.1021 679.0 . 460.0 1139.0 703.7 420.0 1123.8 729)4 .376.4 1105.8 756.7 327.8 1084.5 786.7 2723 1058.9 0.8696 0.4200 13896 .03912. 03788 13700 0.9133 03356 13488 0.9364 0.2892 13257 0.9618 0.2379 1.19% 2000.0 2200.0 2400.0 2600.0 2800.0 3000.0 3200.0 3226:0 695.2 704.9 706.1 0.0367 0.0477 0.0844 0.C459 0.0142 0.0601 0.0522 0 0.0522 823.1 202.5 1025.6 887.0 75.9 962.9 925.0 0 925.0 0.9922 0.1754 1.1676 1.0461 0.0651 1.1112 1.0785 0 1.0785 3000.0 3200.0 3226.0 American Society of Heating and Ventilating Engineers Guide, 1936 be accompanied by a change in the boiling point, and there will be a cor responding change in the latent heat of evaporation. These values are given in Table 6. Specific Heat. The specific heat of water, or the amount of heat (Btu) required to raise the temperature of one pound of water one degree Fahren heit, varies with the temperature, but it is commonly assumed to be unity at all temperatures. Steam tables are based on exact values, however. The specific heat of ice at 32 F is 0.492 Btu per pound. The amount of heat required to raise one pound of water at 32 F through a known temperature interval depends on the average specific heat for the temperature range. Sensible and Latent Heat. The heat necessary to raise the temperature of one pound of water from 32 F to the boiling point is known as the heat of the liquid ox sensible heat. When more heat is added, the water begins to evaporate and expand at constant temperature until the water is entirely changed into steam. The heat thus added is known as the latent heat of evaporation. Table 7. Thermal Properties of Water Temperature Deo F 32 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 212 220 240 260 280 300 350 400 450 500 550 600 700 Sat. Press. Lb per Sq In. 0.0887 0.1217 0.1780 0.2561 0.3628 0.5067 0.6980 0.9487 1.274 1.692 2.221 2.887 3.716 4.739 5.990 7.510 9.336 11.525 14.123 14.696 17.188 .24.97 35.43 49.20 67,01 134.62 247.25 422.61 681,09 1045.4 1544.6 3096.4 CVolume u Ft peb Lb Weight Lb per Cu Ft Specific Heat 0.01602 0.01602 0.01602 0.01603 0.01605 0.01607 0.01610 0.01613 0.01616 0.01620 0.01625 0.01629 0.01634 0.01639 0.01645 0:01650 0.01656 0.01663 0.0166^ 0.01670 0.01676 0.01690 0.01706 0.01723 0.01742 0.01797 0.01865 0:0195 0.0205 0.0219 .0.0241 0.0394 62.42 1.0093 62.42 1.0048 62.42 1.0015 62.38 0.9995 62.31 0.9982 62.23 0.9975 62.11 0.9971 62.00 0.9970 . 61.88 0.9971 ' 61,73 0.9974 61.54 0.9978 61.39 0.9984 61.20 0.9990 61.01 0.9998 60.79 1.0007 60.61 1.0017 60.39 1.0028 60,13 1.0039 59.92 1.0052 . 59.88 1.0055 59.66 1.0068 .59,17 . 1.0104 58.62 1.0148 58:04 1.020 ' .57.41 1.026 . 55.65 1.044 53.62 1.067 . 51.3 ` , - 1.095 48.8 . 1.130 45.7 1.200 41.5 1.362 25.4 30 Chapter 1- -Fundamentals of Heating and Air Conditioning RATE OF EVAPORATION In problems of air conditioning and drying, as well as in other industrial applications of evaporation, such as cooling towers, it is desirable to determine the rate of evaporation. There are two distinct cases of evaporation. Thefirst case is that in which the source of heat is primarily from the water itself and in which the air temperature may even be raised. The second is that in which the heat for evaporation is obtained entirely from the air itself, in which case the air is cooled and the temperature of the water remains substantially constant at the wet-bulb temperature. Both cases, however, may be reduced to a common basis of calculation. It has been found that the increase in the rate of evaporation is nearly in direct proportion to the increase in the air velocity, and that it is in direct proportion to the difference in vapor pressure between the vapor pressure of the water and the pressure of the vapor in the air. . The general formula covering the experimental data may be expressed as follows: J = (o + bv) (*' - e) , (17) where ' rate of evaporation. the rate of evaporation in still air. the rate of increase with velocity. the vapor pressure of the liquid. the vapor pressure in the atmosphere. velocity. . . ' .' , ... . The only difference between case one and case two is that in case one the vapor pressure of the liquid is one of the known or assumed factors, being dependent upon the known temperature of the liquid, while in case two, e' is the vapor pressure corresponding to the wet-bulb tem perature of the air. This wet-bulb or evaporation temperature is dependent upon the dry- bulb temperature and the moisture content, or upon the total heat of the air. as indicated in the previous paragraph. ` The effect of air velocity depends upon whether the flow of air is parallel to the surface or perpendicular to the surface elements. For a flow of air parallel to a horizontal surface w = 0.093 (1 + 2^5) (*' -- ) (approximately) (18) where / w = pounds evaporated per square foot per hour. v = velocity of atmosphere over surfaces, feet per minute. e' = vapor pressure of the water corresponding to its temperature, e = vapor pressure in the surrounding atmosphere.1 For transverse flow, as across a tubular surface, the rate of evaporation is nearly doubled. These relationships are indicated graphically on the chart, Fig. 3. American Society of Heating and Ventilating Engineers Guide, 1936 Chapter'!^--Fundamentals of Heating and Air Conditioning. : Since the difference in vapor pressures is substantially proportional to the difference between the wet- and dry-bulb temperatures (*.., the wetbulb depression) the rate of evaporation is also, for case too, substantially proportionate to the wet-bulb depression. In case too, the rate of sensible heat transfer from the air to the liquid to produce evaporation is substantially the same as the rate of heat transfer with the same type of surface, without moisture being present, but with the same temperature differences. In other words, the rate of heat transfer depends upon the temperature difference only, whether the surface is wet or not. For example, it has been shown that the rate of the value of 5.9 Btu per square foot per degree difference in temperature is obtained for a velocity of 400 fpm, and 9.55 Btu per square foot for a velocity of 800 fpm. ' It will be noted that for these two cases the heat transfer by evapo ration per degree difference in temperature corresponds almost exactly with the heat transfer by convection coils. The similarity may be noted by comparing the formula for heat transfer in parallel flow, UD = 0.026 + -- V (20) fSoo MOO 4- 11300 1<p5 uoo 1000 1- 900 <5 60Q 700 -1- 600 -l- 600 400 300 a XX 200 / # ww* ** A(PV Ifj ' ljvr<> it1 V>sei-rat'ortSL /Co rHa wi XXI-iCar rier Exp rii ten s c. rofi tfj; with the heat transfer by evaporation with parallel flow. The relationship will be seen to be very close in both cases and would indicate that the heat transfer by evaporation is actually brought about by a process of con-, vection. . . . . .................. The difference in form of the two formulae may be due in part tri errors in observation at the higher and lower velocities. , In cooling air and condensing out the moisture therefrom the heat transfer is considerably more rapid than when the air is dry and no moisture is condensed. In general the rate of heat transmission on the air side is increased an amount which is proportionate to the latent heat removed as compared with the sensible heat removed. That is, if the latent heat removed was 50 per cent of the sensible heat removed, then the conductivity of the surface in contact with the air would be increased =2 approximately 50 per cent. - 100{ 0. 1l1 Air Veto vty inf eet 90Ti Wm fie i 1 | Til % l ri Fig. 3. Heat Transmitted by Evaporation heat transfer with air flowing across staggered coils (transverse flow) may be represented by the formula: REFERENCES A Review of Psychrometric Charts, by C. O. Mackey (Heating and Ventilating, June, July, 1931). ' A New Psychrometric Chart, by C. A. Bulkeley (A.S.H.V.E. Transactions, Vol. 32, 1926). .. .. Air Conditioning Applied to Cold Storage and a New Psychrometric Chart, by C. A. Bulkeley (Refrigerating Engineering, February; 1932). `1 i ) ! where _________1_ Ut 0.0447 + 50.66 V (19) f/t = heat transfer, expressed in Btu peg hour per square foot per degree difference in temperature between steam and air, for transverse flow. Air Conditioning-Theory, by John A. Goff (Refrigerating Engineering, January, 1933): 191R1a).tio/.nal Psychro.me.tri.c F.or.mu.lae.,b.y W..H.. Carrie. r (A.S.M.E. Transactions, Vol.. ,33, Temperature of Evaporation, by W. H. Carrier (A.S.H.V.E. Transactions, Vol. 24,; 1918). . ... . . Principles of Engineering Thermodynamics, by Kiefer and Stuart. At a velocity of 400 fpm, Ut = 5.8; at a velocity of 800 fpm, Ut = 9.3. Basic Theory of Air Conditioning, by Lawrence Washington (Western Conference on Air Conditioning, San Francisco, Calif., February 9-10, 1933). . Referring to Fig. 3, showing the rate of heat transmission by evapo ration for different air velocities, it will be noted that for transverse flow there are 560 Btu per hour per square foot transferred per inclf difference of vapor pressure at a velocity of 400fpm, and 910 Btu per hour per square foot per inch difference in vapor pressure at a velocity of 800 fpm. 0ne inch of vapor pressure difference corresponds approximately to 95 deg difference between the wet- and dry-bulb temperature. Dividing by. 95, Mixtures of Air and Water .Vapor, by C, A. Bulkeley (Refrigerating Engineering, January, 1933). _ ' . Temperature of Evaporation of Water into Air, by W. H. Carrier and D. C. .Lindsay (A.S.M.E. Transactions, 1924). - .. . . Chemical Engineering, by Lewis, Walker and McAdams. : . ..;.... ' Fan Engineering, Buffalo Forge Co. ... : ; . - ' :':,The Psychrometric Chart, by E. V. Hill (Aerologist, April, May, June; 1932). . 32 .. ,, i American Society of Heating and Ventilating Engineers Guide, 1936 PROBLEMS IN PRACTICE 1 Given air at 70 F dry-bulb and 50 per cent relative humidity with a baro metric pressure of 29.00 in. Hg, find the weight of vapor per pound of dry air. Pressure of saturated vapor = et = 0.7387 in. Hg (Table 5). From Equation 5a, W = 0.622 / 0.5 X 0.7387 \ V29.00 - (0.5) (0.7387)/ W -- 0.008024 lb of vapor per pound of dry air at 70 F dry-bulb and 50 per cent relative humidity. Approximate Method: Weight of saturated vapor per pound of dry air = Wt = 0.01574 lb (Table 5). 0.01574 X 0.5 = 0.0787 lb of vapor per pound of dry air at 70 F dry-bulb and 50 per cent relative humidity. 2 Given air with-a dry-bulb temperature of 80 F, relative humidity of 55 per cent* and a barometric pressure of 28.85 in. Hg, calculate the weight of a cubic foot of mixture. . Pressure of saturated vapor at 80 F = et = 1.0316 in. Hg (Table 5). Pressure of the vapor in the mixture = 1.0316 X 0.55 = 0.5676 in. Hg. Pressure of the dry air in the mixture = 28.85 - 0.5676 = 28.282 in. Hg. pV -- wR (t + 460) (J? = 0.753 when partial pressure of air is expressed in in. Hg). 28.282 X 1 = da X 0.753 X (80 + 460) 28 282 da = 0 753 X 540 = 0-6955 lb. = weight of dry air in 1 cu ft of the mixture. ' Likewise from Equation 4a, dv = 1 21 X 540 = -000868 = weight of vapor per cubic feet at 55 per cent relative humidity. Weight of 1 cu ft of the mixture = 0.06955 + 0.000868 = 0.070418 lb. 3 Given air with a dry-bulb temperature of 75 F, a relative humidity of 60 per . cent, and a barometric pressure of 28.80 in. Hg, calculate, the volume of 1 lb of the mixture. Pressure of saturated vapor at 75 F = et -- 0.8745 in. Hg. Pressure of vapor in the mixture = 0.8745 X 0.6 = 0.525 in. Hg. Pressure of dry air in the mixture = 28.80 -- 0.525 = 28.275 in. Hg. 28 275 da. = 0753 X 535 = '0701818 = weiS^t of dry air in 1 cu ft of the mixture. From Equation 4a, . ^ =' 1 2i ><5535 0.000811 lb = weight of vapor per cubic feet at 55 per cent relative humidity. ' Weight of 1 cu ft of the mixture = 0.07018 ,-f 0.000811 = 0.070991 ib. ` Volume of 1 lb of the mixture = q-070991 ~ 14 08 cu ft- , 4 Given saturated air at a temperature of 75 F and a barometric pressure of 29.92 in. Hg, determine the total heat of the mixture per pound of dry air. From Equation 11 and Tables 5 and 6, Cpa -- mean specific heat at constant pressure of dry air *= 0.24. : hfg = latent heat of vaporization at the wet-bulb temperature = 1050.1 Btu per ft>. 34 -W* : ?' Chapter 1--Fundamentals of Heating and Air Conditioning Wt' = weight of water vapor mixed with each pound of dry air = 0.01873 lb. S = 0.24 (75 - 0) + (0.01873) (1050.1). S = 37.67 Btu per lb of dry air. , 5 0 Given air at 85 F dry-bulb temperature, 75 F wet-bulb temperature, and a barometric pressure of 29.92 in. Hg; determine the total heat of the mixture per pound of dry air. From Equation 10 and Tables 5 and 6, Cpa = 0.24. h'fg = 1050.1 Btu. Relative humidity = 62.3 per cent (from psychrometric chart). W = 0.622 ( 2992^ ) = 001612lbof moisture per lb of dry air. S = 0.24 (85 - 0) + 0.01612 [1050.1 + 0.45 (85 - 75)]. S = 37.40 Btu per pound of dry air. It will be seen from Questions 4 and 5 that the total heat is a function of the wet-bulb temperature. 6 It is desired to maintain a temperature of 80 F and a relative humidity of 50 per cent in a factory where the equipment gives off 6,000 Btu per hour; If the entering air is at 70 F with an average barometric pressure of 29.92 in. Hg; determine the relative humidity, and the pounds of air required per hour if there is no heat interchange between the walls, windows, or floors of the building. Pressure of saturated vapor at 80 F = 1.0316 in. Hg (Table 5). Pressure of vapor in the mixture = 1.0316 X 0.5 = 0.5158 in. Hg. falsa)- 001091 lb' Pressure of saturated vapor at 70 F = 0.7387 in. Hg. With the same specific humidity 0.01091 = 0.622 (/29,920_73(8o7,7V387 X*)\) . - <j> = 69.8 per cent relative humidity at 70 F. h = 0.24 X 80 + 0.01091 (1059.2 -f 0.45 X 80) = 31.15 Btu per pound, the heat content of the mixture at 80 F and 50 per cent relative humidity. h = 0.24 X ft) + 0.01091 (1059.2 + 0.45 X 70) = 28.70 Btu per pound, the heat content of the mixture at 70 F and the same specific humidity. - . 31.15 -- 28.70 = 2.45 Btu to be removed per pound of air. 6000 Btu = heat given off by equipment per hour. 6200^0 = 2449 lb of air required per hour. 7 Given 1 lb of dry air at 78 F and a barometric pressure of 29.92 in. Hg; calculate the volume. If the temperature is raised to 96 F and the volume remains constant, what will be the new pressure. Pi, in in. Hg? PV = wR (1 + 460) R (for air) = 53.34. \. . W = 1 lb. ' P = absolute pressure, pounds per square foot. ,, IX 53.34 X (78 + 460) ' ; 29.92 X 0.491 X 144 V -- 13.57 cu ft = volume of 1 lb. \ 35 American Society of Heating and Ventilating Engineers Guide, 1936 P, = r, A 7V ' 7VP, r, . p _ (96 + 460) (29.92 X 0.491 X 144) 1 (78 + 460) (0.491 X 144) 30.90 in. Hg. 8 Given saturated air at a temperature of 75 F and a barometric pressure of 29.92 in. Hg; determine the heat content of the mixture per pound of dry air,: including the heat content of the liquid above 32 F. From Equation 12, . h = 0.24 (/ - 0) + W (1059.2 + 0.45/). where . As = 1059.2 + 0.45/ (Empirical equation derived from Keenan's Steam Tables:) / = 75 F. W = 0.01873 lb of water vapor (Table 5). h = 0.24 (75 - 0) + 0.01873 (1059.2 + 0.45 X 75). h = 38.47 Btu per pound of dry air. ' 9 A. building requires 50,000 cu ft of air per hour to be raised from --10 F dry-bulb and 75 per cent relative humidity to 72 F dry-bulb and 30 per cent relative humidity. Determine the amount of heat and the weight of water which it is necessary to supply per hour if the temperature of the supply water is 50 F and the barometric pressure is 28.75 in. Hg. Assume air volume to be dry air at 70 F. . Weight of air = 0.075 X 50,000 = 3750 lb per hour. From Table 5, . ... Pressure of vapor in the mixture, outside air = 0.75 X 0.0221 = 0.0166 in. Hg. ( 28 n 75 m -- fifi 0 0166 \ ) - = ' 4. 9-3589 K>. . From Table 6, ' Pressure of vapor in the mixture, inside air = 0.30 X 0.7906 = 0.2372 in. Hg. * Specific humidity, inside air 0.622 (g8 = 0 005^74 lb- Water to be added = 3750 (0.005174 -- 0.0003589 ) = 18.06 lb per hour. Heat content, inside air = 0.24 X 72 + 0.005174 (1059.2 + 0.45 X 72) = 22.925 Btu per gound. Heat content, outside air = 0.24 X (-10) + 0.0003589 (1059.2 + (0.45 X -10) = .' --2.021 Btu per pound. . Btu added incident to the water per pound of dry air. ' (0.005174 - 0.0003589) (50 - .32) = 0.0867 Btu per pound. . Heat requirement per hour = (22.925 -- (--2.021 + 0.0867) X 3750 = 93,221 Btu.' 10 Determine the amount of heat and water that must be extracted to cool' 3750 lb of air (weighed dry) from 95 F and 60 per cent relative humidity to 50 F and 100 per cent relative humidity with a barometric pressure of 28.75 in. Hg. Pressure of vapor in the mixture, outside air = 6.6 X 1.659 = 6.995 in. Hg. : . . Specific humidity, outside air = 0.622 (28 75 --995) ~ 0.02231b. '" ' Specific humidity, inside air = 0.007626 lb. . -"'r Weight of water to be extracted per hour = (0.0223 -- 0.007626) X 3750 = 55.03 lby Heat content, outside air = 0.24 X 95 + 0.0223 (1059.2 + 0.45 X 95) = 47.37 Btu per pound. ' ...... 1 ; Heat content, inside air = 0.24 X 50 + 0.00764 (1059.2 + 0.45 X 50) '= 20.26 lB,tu per pound. . ' . Heat to be extracted = (47.37 - 20.26) X 3750 = 101,662 Btu. , + ; ! v ; 36 Chapter 2 REFRIGERATION ,Classification of Systems, Refrigerants, Mechanical Compression Systems, Theoretical Cycle, Refrigerating Effect per Pound Coefficient of Performance, Steam Ejector System, System Characteristic, Closed Absorption System, Open Adsorption Systems, Reverse Cycle THE various types of refrigeration systems most' commonly used for air conditioning purposes may be classified fundamentally as follows: 1. Compression Systems. .... . : a. Mechanical--Reciprocating, Rotary, and Centrifugal........ ........ b. Ejector. , 1. ,* ` .... 2. Absorption Systems. - _ .. a. Closed. b. Open. ' ' . - < Of these, the mechanical systems are the most extensively used at the present time and will- be given complete consideration in the following discussion. REFRIGERANTS The common refrigerants are volatile liquids which produce refrigera tion by their evaporation under reduced pressure. Factors usually in fluencing the choice of refrigerant are safety, chemical stability, operating pressures and adaptability for the type Of system to be'used. Of the six refrigerants whose properties are listed in Tables 1. to 6, ammonia, carbon dioxide, dichlorodifluorometh.ane (F12) and methyl chloride are used in reciprocating and rotary mechanical compression systems. Monofluorotrichloromethane (Fu) and water are used in cen trifugal compression systems. Water is used almost to the exclusion of other refrigerants in ejector systems. Closed absorption systems may use ammonia, methyl chloride, water, or others as the refrigerant. MECHANICAL REFRIGERATION SYSTEMS , While the mechanical refrigeration systems differ in the; methods used for compression, of the refrigerant vapor, they are all fundamentally similar. Refrigerant vapor, usually saturated or slightly superheated, is j drawn into a compressor (see Fig. 1).. It is then compressed and dis charged at a higher pressure to a condenser. The vapor is condensed as it . contacts a heat transfer surface over-which is flowing a cooling medium such.as water, air or a combination of the -two.. The liquid: refrigerant V;' ' ' ''. 37 ' ' American Society of Heating and Ventilating Engineers Guide, 1936 flows to the evaporator through an expansion valve which reduces its pressure arid regulates its flow. The evaporator absorbs heat from a medium which is to be cooled. When this rnedium is water or brine, the evaporator is known as a water or brine cooler and the refrigeration system, if used for air cooling, is known as an indirect system. When the medium cooled is air, the evaporator is known as a direct expansion cooler and the system is known as a direct expansion system. Fundamentally, the function of the system is to absorb heat at one temperature and pump it to a higher temperature, where it may be re-' moved by an available cooling medium. In order to conserve refrigerant, Heat of Compression Added to Gas Chapter 2--Refrigeration theoretical cycle starts with saturated vapor, operation is common at a condition of superheated. vapor (as at di). Moreover, expansion may tart either with a mixture of liquid and vapor or with a sub-cooled liquid, s at ci with expansion to eu It is obvious that this latter is desirable as ft increases the refrigerating effect. Area aibicdaai represents the work of such a superheated cycle, while the area eidigifid represents the refriger ating effect of the cycle with superheated vapor and sub-cooled refrigerant liquid. It will be noted on the pressure-volume diagram the volume of the liquid is indicated by a dotted line close to and parallel to the ordinate. 1 virtually all refrigeration systems are completely closed arid the same refrigerant is recirculated. Theoretical Mechanical Refrigeration Cycle . The complete mechanical refrigeration cycle may be illustrated on' the temperature-entropy diagram, and also on the pressure-volume diagram both of which are shown.in Fig. 2. ' ' Considering the theoretical cycle, saturated vapor is drawn into the compressor at a and compressed at-constant entropy (adiabatically) and then delivered to the condenser at b. Condensation occurs at constant' temperature Tt from b to c with a contraction from the vapor to th*e liquid volume. The line cd represents cooling from the temperature of . the condenser to that of the evaporator by an external cooling means. At the same time, the pressure is lowered to Pi. Evaporation then occurs', from dto a at temperature Tu completing the work cycle dbcda. Since no, . external means of cooling the refrigerant liquid is normally available, the cooling is generally accomplished by evaporation of a portion qj the refrigerant. Since- the work of expansion' is usually used up as friction in the expansion valve, this process is carried on at constant total heat,' as represented by the line ce, on the temperature-entropy diagram. Thus the refrigerating effect is represented by an area eagfe. While the normal * 38 Fig. 2. Theoretical Dichlorodifluoromethane (F,,) Cycles It is obvious that it is necessary to include the work of pumping the liquid as well as pumping the vapor as part of the refrigeration work. Theoretical Work per Pound . The temperature-entropy and pressure-volume diagrams are based, on one pound of the refrigerant. Likewise, the theoretical work and the refrigerating effects are conveniently based on a pound of refrigerant'. The compression work pier pound may be found by several methods. The temperature-entropy method starts with state point a. Since the quality of a is known, the heat content of the vapor -ffa is known, and also the entropy Sa. Since Sa = Sb and with 7* given, Hi> can be determined. If W = work in foot-pounds per piound of refrigerant, then W = (Hb - JZa) X 778 ~ . (1) The pressure-volume method starts with state pioint a, whose pressure , and specific volume are known. The work of compression is the adiabatic work of compression from Pi to Pi, plus the work of expelling the vapor ' at constant pressure Pt minus the external work' of evaporation of the , vapor to volume Fi at pressure Pi. (2) / American Society of Heating and Ventilating Engineers Guide, 1936 . . Table 1. Properties of Ammonia . .. Sat. Temp. . .F Lb per Sq In. Volume ' Liquid Vapor Heat Content and Entropt Taken From --40 F Heat Content liquid Vapor Entropy Liquid Vapor 100 F Superheat 200.F Superheat Ht ct Entropy Ht. Ct. Entropy .o 30.42 0.02419 5 34.27 0.02432 10 38.51 0.02446 IS 43.14 0.02460 20 48.21 0.02474 25 53.73 0.02488 30 59.74 0.02503 35 66.26 0.02518 40: 73.32 0.02533 45 ; 80.96 0.02548 50 89.19 0.02564 55 98.06 0.02581 60 107.6 0.02597 65 117.8 0.02614 70 . 128.8 0.02632 75 . 140.5 0.02650 80 153.0 0.02668 85 . 166.4 0.02687 90 180.6 0.02707 95 195.8 0.02727 100 211.9 0,02747 105 228.9 0.02769 9.116 8.150 7.304 6.562 5.910 5.334 4.825 4.373 3.971 3.614 3.294 3.008 2.751 2.520 2.312 2,125 1.955 1.801 1.661 1.534 1.419 1.313 42.9 611.8 0.0975 1.3352 666.8 1.4439 720.3 1.5317 48.3 613.3 0.1092 1.3253 668.9 1.4339 722.7 1.5215 53.8 614.9 0.1208 1.3157 670.9 1.4242 725.0 1.5115 59.2 616.3 0.1323 1.3062 673.0 1.4148 727.3 1.5018 64.7 617.8 0.1437 1.2969 675.0 1.4056 729.6 1.4925 70.2 619.1 0.1551 1.2879 677.0 1.3965 731.9 1.4833 75.7 620.5 0.1663 1.2790 678.9 1.3879 734.2 1.4744 81.2. 621.7 0.1775 1.2704 680.8 1.3794 736.5 1.4658 86.8 623.0 0.1885 1.2618 682.7 1.3712 738.6 1.4575 92.3 624.1 0.1996 1.2535 684.6 1.3630 740.9 1.4493 97.9 625.2 0.2105 1.2453 686.4 1.3552 743.1 1.4412 103.5 626.3 0.2214 1.2373 688.1 1.3474 745.3 1.4335 109.2 627.3 0.2322 1.2294 689.9 1.3399 747.4 1.4260 114.8 628.2 0.2430 1.2216 691.7 1.3326 749.5 1.4186 120.5 629.1 0.2537 1.2140 693.3 1.3254 751.6 1.4114 126.2 629.9 0.2643 1.2065 695.0 1.3184 753.7 1.4044 132.0 630.7 0.2749 1.1991 696.6 1.3116 755.8 1.3976 137.8 631.4 0.2854 1.1918 698.2 1.3048 757.9 1.3909 143.5 632.0 0.2958 1.1846 699.7 1.2983 759.9 1.3843 149.4 632.6 0.3062 1.1775 701.2 1.2919 761.9 1.3783 155.2 633.0 0.3166 1.1705 702.7 1.2855 763.8 1.3718 161.1 633.4 0.3269 1.1635 704.2 1.2793 765.7 1.3655 1.3172 Table 2. Properties of Carbon Dioxide Sat. Temp. F Abb Press. Lb per Sq In. Volume Liquid Vapor Heat Content and Entropt Taken From -40 F Heat Content liquid Vapor Entropy 50 F Superheat 100 F Superheat Liquid Vapor' Ht. Ct. Entropy Ht:Ct: Entropy 0 305.5 0.01570 0.2904 18.8 138.9 0.0418 0.3024 153,7 0.3342 167,5 0.3612. 5 332.0 0.01592 0.2661 20.3 138.8 0.0472 0.3000 153.7 0.3312 167.8 0.3582 10 360.2 0.01614 0.2437 24.0 138.7 0.0526 0.2970 153.7 0.3281 168.0 0.3550 15 390.0 0.01637 0.2236 26.7 138.5 0.0581 0:2939 153.7 0.3257 168.3 0:3517 20 421.8 0.01663 0.2049 29.4 138.3 0.0638 0.2909 153.7 0.3227 168:6 0.3489 25 455.3 0.01690 0.1879 32.3 138.1 0.0697 0.2879 153.7 0.3196 168.8 0:3464 ' 30 490.8 0.01719 0.1722 35.4 137.8 0.0758 0.2849 153.7 0.3164 169.1 013441 35 529.3 0:01752 0.1577 38.5 137.3 0.0817 0.2813 153.7 0.3147 169.3 0.34i5 40 567.8 0.01787 0.1444 .41.7. 136.7 0.0874 0.2776 153.7 0.3132 169.6 0.339145 609.6 0.01826 0.1321 45.0 135.9 0.0935 0.2739 153.7 0.3112 169.9 0.3365 50 653.6 0.01868 0,1205 48.4 135.0 0.1000 0.2699 153.7 0.3081 170.1 0.3342 55 700.0 0.01917 0.1096 51.9 133.7 0.1062 0.2656 153.7 0.3051 170.4 0.3320 60 748.6 0.01970 0.0994 55.5: 132.1 0.1135 0.2608 153.7 0.3022 170.7 0.3297 65 799.8 0.02034 0.0899 59.4 130.2 0.1206 0.2554 153.7. 0.2995 170.9 0.32?7 . 70 853.4 0.02112 0.08040 63.7 127.5 0.1282 0,2487 153.7 0.2971 171'. 2 6.3257 ` 75 ' 909.7 0.02217 0.07072 68.4 123.7 0.1370 0.2404 153.7 0.2947 171.4 0.3237 80 968:7 0.02370 0.06064 73.9 118.7 0.1476 0.2304 153.7 0.2927 171.7 0.3220 85 1030.3 0.02620 0.05006 81.4 112.2 0.1668 0.2169 153.7 0.2909 180.0 0,3204: 87.8 1069.9 0.03454 0.03454 97.0 97.0 0.1880 0.1880 153.7 0.2901 180.1 0.3199 1.28 40 2Chapter --Refrigeration Table 3. Properties of DichlorodifluoromeThane (Fi2) ---- Sat. Temp- F Press. Sa In. Liquid Vapor Heat Content and Entropt Taken From --40 F Heat. Content Liquid Vapor Entropy. Liquid Vapor 25 F Superheat 50 F Superheat Ht. Ct. Entropy Ht Ct. Entropy 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 23.87 0.0110 1.637 26.51 0.0111 1.485 29.35 0.0112 1.351 32.44 0.0112 1.230 35.75 0.0113 1.121 39:33 0.0114 1.025 43.16 0.0115 0.939 47.28 0.0116 0.863 51.68 0.0116 0.792 56.38 0.0117 0.730 61.39 0.0118 0.673 66.74 0.0149 0.622 72.41 0.0119 0.575 78.44 0.0120 0.532 84.82 0.0121 0,493 91.60 0.0122 0.458 98.76 0.0123 0.425 106.4 0.0124 0.395 8.25 78.21 9.32 78.79 10.39 79.36 11.48 79.94 12.55 80.49 13.66 81.06 14.76 81.61 15.88 82.16 17.00 82.71 18.14 83.26 19.27 83.78 20.41 84.31 21.57 84.82 22.72 85.32 23.90: 85.82 25.08 86.32 26.28 86.80 27.48 87.28 0.01869 0.17091 81.71 0.02097 0.17052 82.29 0.02328 0.17015 82.90 0.02556 0.16981 83.49 0.02783 0.16949 84.09 0.03008 0.16920 84.67 0.03233 0.16887 85.25 0.03458 0.16860 85.83 0.03680 0.16833 86.41 0.03904 0.16808 86.96 0.04126 0.16785 87.54 0.04348 0.16763 88.09 0.04568 0.16741 88.64 0.04789 0.16721 89.18 0.05009 0.16701 89.72 0.05229 0.16681 90.25 0.05446 0.16662 90.78 0.05665 0.16644 91.27 0.17829 85.26 0.17786 85.89 0.17747 86.51 0.17710 87.13 0.17679 87.76 0.17643 88.37 0.17612 88.97 0.17582 89.56 0.17554 90.16 0.17528 90.76 0.17505 91.38 0.17482 91.93 0.17458 92.51 0.17436 93.11 0.17417 93.66 0.17397 94.23 0.17379 94.80 0.17361 95.33 0.18547 0.18502 0.18460 0.18420 0.18382 0.18349 0.18315 0.18285 0.18256 0.18227 0.18203 0.18181 0.18155 0.18132 0.18114 0.18092 0.18075 0.18056 90 114.3 0.0125 0.368 28.74) 87.74 0.05882 0.16624 91.77 0.17344 95.86 0.18040 95 122.8 0.0126 0.343 29.93 88.19 0.06100 0.16604 92.27 0.17323 96.39 0.18020 100 131.6 0.0127 0.319 31.16 88.62 0.06316 0.16584 92.75 0.17308 96.92 0.18004 105 140.9 0.0128 0.298 32.40 89.03 0.06534 0.16564 93.24 0.17291 97.46 0.17991 110 150.7 0.0129 0.277 33.65 89.43 0.06749 0.16542 93.66 0.17274 97.93 0.17976 115 161.0 0.0130 0.258 34.90 89.80 0.06965 0.16520 94.07 0:17253 98.40 0.17955 120 171.8 0.0132 0.240 36.16 90.15 0.07180 0.16495 94:47 0.17233 98.84 0.17939 n= = 1.133 cv Temp. F Press. Lb per Sq In. liquid Table 4. Properties of Water Vapor Heat Content and Entropt Taken From --32 F Heat Content Liquid Vapor Entropy Liquid Vapor 50 F Superheat 100 F Superheat Ht Ct Entropy Ht Ct Entropy 32 35 40 45 50 55 60 65 70 75 80 85 .. 90 95 100 105 0.0887 0.01602 3296.0 0.1000 0.01602 2941.0 0.1217 0.01602 2441.0 0.1475 0.01602 2034.0 0.1780 0.01602 1702.0 0.2140 0.01603 1430.0 0.2561 0.01603 1206.0 0.3054 0.01604 1021.0 0.3628 0.01605 868.0 0.4295 0.01606 740.0 0.507 0.01607 632.9 0.596 0.01609 543.3 0.698 0.01610 467.9 0.815 0.01612 404.2 0.949 0.01613 350.3 1.101 0.01615 304.4 0.00 1073.0 0.0000 2.1826 1096.9 2.2277 1120.8 2.2688 3.02 1074.4 0.0062 2.1724 1098.3 2.2172 1122.2 2.2581 8.05 1076.8 0.0163 2.1555 1100.6 2.2000 1124.5 2.2406 13.07 1079.2 0.0262 2.1390 1102.9 2.1832 1126.7 2.2234 18.08 1081.5 0.0361 2.1230 1105.2 2.1667 1129.0 2.2066 23.08 1083.9 0.0459 2.1073 1107.5 2.1506 1131.3 2.1902 28.08 1086.2 0.0556 2.0920 1109.8 2.1349 1133.5 2.1742 33.08 1088.6 0.0652 2.0771 1112.2 2.1196 1135.8 2.1585 38.07 1090.9 0.0746 2.0625 1114.5 2.1046 1138.1 2.1432 43.06 1093:2 0.0840 2.0483 1116.7 2.0900 1140.3 2.1283 48.05 1095.5 0.0933 2.0344 1119.0 2.0758 1142.5 2.1138 53.04 1097.8 0.1025 2.0208 1121.2 2.0619 1144.7 2.0996 58.03 1100.0 0.1116 2.0075 1123.4 2.0483 1146.8 2.0857 63.01 1102.3 0.1206 1.9946 1125.6 2.0350 1148.9 2.0721 68.00 1104.6 0.1296 1.9819 1127.9 2.0220 1151.1 2.0588 72.98 1106.8 0.1384 1.9695 1130:2 2.0093 1153.2 2.0458 For properties of steam at high' temperatures, see Page 27. 41 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Chapter 2--Refrigeration Table 5. Properties of Methyl Chloride Sat. Temp. P Ass Press. Lb psb Sq In. Volume Liquid Vapor Heat Content and Entbopt Taken From -40 P Heat Content Liquid Vapor Entropy Liquid Vapor 100 F Superheat 200 F Superheat Ht Ct Entropy Ht. Ct. Entropy 0 s 10 IS 20 25 , 30 35 40 45 50 55 60 65 70 75 80 85 90 95 100 105 110 115 120 18.5 0.01628 20.89 0.01635 23.3 0.01645 25.8 0.01652 28.3 0.01660 32.0 0.01669 35.0 0.01678 38.8 0.01689 42.8 0.01700 46.5 0.01710 51.0 0.01721 55.7 0.01727 61.0 0.01734 66.8 0.01746 72.6 0.01758 79.5 0.01768 87.0 0.01779 93.9 0.01790 102.0 0.01801 108.7 0.01813 117.0 0.01825 124.3 0.01836 133.0 0.01847 143.0 _______ __ 154.0 -- 5.00 4.52 4.09 3.73 3.37 3.07 2 78 2.55 2.32 2.13 1.94 1.79 1.64 1.51 1.39 1.28 1.18 1.09 1.01 0.94 0.87 ....L... ' _____ ___ ... -- 14.5 16.3 18.0 19.9 21.7 23.5 25.2 27.0 28.9 30.7 32.5 34.5 36.5 38.5 40.5 42.5 44.5 46.3 48.0 50.0 52.0 53.8 55.5 57.3 59.0 194.0 195.3 196.5 198.0 199.0 200.0 201.2 202.4 203.7 204.5 205.3 206.1 207.0 207.5 208.0 208.5 209.0 209.5 210.0 210.3 210.5 210.6 210.7 210.8 211.0 0.032 0.424 215.6 0.036 0.4225 217.0 0.040 0.421 218.5 0.044 0.420 219.8 0.048 0.418 221.0 0.052 0.417 222.1 0.056 0.415 223.4 0.060 0.414 224.5 0.064 0.413 225.7 0.068 0.412 226.8 0.071 0.410 227.9 0.075 0.408- 228.8 0.079 0.406 229.6 0.083 0.404 230.5 0.086 0.402 231.3 0.090 0.400 232.2 0.093 0.398- 233.0 0.097 0.396 233.8 0.100 0.394 234.5 0.104 0.392 235.2 0.107 0.390 236.0 0.111 0.388 237.0 0.114 0.386 237.9 0.118 0.384 238.5 0.121 0.382 239.0 0.467 0.464 0.463 0.461 0.460 0.459 0.457 0.454 0.453 0.451 0.449 0.448 0.446 0.443 0.441 0.439 0.437 0.435 0.433 0.432 0.431 0.430 0.428 0.427 0.425 237.2 238.5 240.0 241.0 242.5 244.0 245.2 246.5 247.7 249.1 250.5 251.7 253.0 254.3 255.5 256.8 257.9 259.2 260.4 261.5 262.4 263.3 264.3 265.0 265.6 0.507 0.503 0.500 0.498 0.496 0.494 0.493 0.492 0.490 0.488 0.487 0.486 0.484 0.483 0.481 0.479 0.478 0.477 0.476 0.475 0.474 0.473 0.472 0.470 0.468 (F)Table 6. Properties of Monofluorotrichloromethane Sat. Temp. F Abs Press. Lb per Su l- Volume Liquid Vapor Heat Content and Entbopt Taken Fbom -40 F Heat Content Liquid Vapor Entropy Liquid Vapor 25 F Superheat 50 F Superheat Ht. Ct. Entropy Ht. Ct. Entropy ? so 0.01020 13.7 7.81 90.4 0.0178 0.1975 93.9 0.2049 97.4 0.2120 2.96 0.01024 12.1 8.81 91.2 0.0200 0.1974 94.7 0.2047 98.2 0.2117 1 38 0.01028 10.7 9.82 92.0 0.0222 0.1973 95.5 0.2045 99.0 0.2114 3 85 0.01032 9.53 10.8 92.8 0.0243 0.1971 96.3 0.2043 99.8 0.2111 20 25 30 4.36 0.01036 4.94 0.01040 5.57 0.01045 8.49 7.58 6.77 11.9 12.9 13.9 93.7 0.0264 0.1970 94.5 0.0286 0.1969 95.3 0.0307 0.1969 97.2 0.2041 100.7 0.2109 98.0 0.2039 101.5 0.2107 98.8 0.2038 102.3 0.2105 35 40 6.27 0.01049 6.08 7.03 0.01053 5.46 14.9 16.0 96.1 0.0328 0.1968 99.6 0.2037 103.1 0.2103 96.8 0.0349 0.1968 100.3 0.2036 103.8 0.2101 45 7.88 0.01057 4.92 17.0 97.6 0.0370 0.1967 101.1 0.2035 104.6 0.2099 50 8.79 0.01062 4.44 18:1 98.4 0.0391 0.1967 101.9 0.2034 105.4 0.2098 55 9.80 0.01066 4.02 19.1 99.2 0.0412 0.1967 102.7 0.2033 106.2 0.2097 60 10.9 0.01071 3.64 20.2 100.0 0.0432 0.1967 103.5 0.2033 107.0 0.2096 65 12.1 0.01076 3.30 21.3 100.8 0.0453 0.1967 104.3 0.2032 107.8 0.2094 70 13.4 0.01081 3.00 22.4 101.5 0.0473 0.1967 105.0 0.2032 108.5 0.2093 75 14.8 0.01086 2.74 23.5. 102.2 0.0493 0.1967 105.7 0.2031 109.2 0.2092 80 16.3 0.01091 2.50 24.5 102.9. 0.0513 0.1966 106.4 0.2030 109.9 0.2090 85 17.9 0.01096 2.28 25.6 103.6 0.0533 0.1966 107.1 0.2029 110.6 0.2089 90 19.7 0.01101 2.09 26.7 104.4 0.0553 0.1966 107.9 0.2028 111.4 0.2088 95 21.6 0.01106 1.918 27.8 105.1 0.0573 0.1966 108.6 0.2028 112.1 0.2087 100 23.6 0.01111 1.761 28.9 105.7 0.0593 0.1965 109.2 0.2027 112.7 0.2085 105 25.9 0.01116 1.620 30.1 106.4 0.0613 0.1965 109.9 0.2026 113.4 0.2084 n= _ = 1.13 It-is frequently helpful to think of the compression of the vapor in terms of head. The head may be likened to a vertical column of vapor in which is located the vapor to be compressed. The compression occurs when the vapor is moved down from a level corresponding to Pi to.a new level corresponding to P2, in equilibrium with the surrounding vapor. If this process is carried on isen tropically, the result will be the same as indicated previously. Then if A is the head in-feet, W--h (3) This relationship may easily be seen from the fact that a small difference of head dh divided by the specific volume of the vapor V is equal to the ' increment of pressure difference dP. Thus, dh. = VdP; also it can be seen by a comparison of the diagram that VdP = SdT, whence by integration all three of the previous ex pressions may be derived. '; Head-is very useful in considering the performance of centrifugal com pressors, which merely substitute a centrifugal for the gravity head. .Itis also useful in considering problems of fluid flow. In these problems, the head per degree can be obtained either by direct calculation or : 42 j' approximately by dividing the total head by the temperature difference Ti -- T\. The velocity head loss can then be calculated in degrees, using the customary formula V2 = 2gh. Refrigerating Effect per Pound The refrigerating effect per pound, is computed by the same method, regardless of the type of refrigeration system. The solution is indicated on the temperature-entropy diagram of Fig. 2. Assuming that the vapor leaving the evaporator is saturated, the refrigerating effect.in Btu per pound is obtained by subtracting from the heat content of the vapor at temperature Tu the heat content of the liquid at r2, or if the liquid is sub-cooled, the liquid temperature. Thus, the refrigerating effect in Btu per pound, is equal to . . ' H& - Hc = Ha - -He (4) If the vapor entering the compressor is superheated or supersaturated, a correction in the heat of the vapor is made accordingly. . The. unit of refrigeration is the ton, based on the latent heat of fusion of one ton of ice in 24 hours. Thus one ton = 200 Btu per minute = 12,000 Btu per hour. .43 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Coefficient of Performance ' The coefficient of performance of a refrigeration system is the ratio of the refrigerating effect to the work of compression, both expressed in the same units. The ideal or Carnot coefficient of performance depends upon the tem peratures Ti and T2 in much the same way as the ideal efficiency of a steam engine depends upon its working temperature, with an inverse relationship. Ideal C. of P. = (5) Evidently the smaller the compression range, the less power will be required to produce a given refrigerating effect. The theoretical coefficient of performance of actual refrigerants is always less than the ideal due to the tendency of most refrigerants to superheat when compressed, and due to the heat of the liquid which must Table 7. Theoretical Comparison of Various Refrigerants1 Refrigerant Work per Lb . Ft Lb Equiva lent Head Ft Gas Temp. Leavino Comp. F Reprig. Effect per Lb Lb' per Min per Ton 53,900 53,900 209 489.8 0.408 9,940 9,940 146 64.0 3.125 Dichlorodifluoro- . 6,280 6,280 134 55.74 3.638 16,500 16,500 183 156.9 1.275 Monofluorotrichloro- methane (Fn) 7,050 7,050 101 74.0 2.605 114,300 114,300 360 1010.8 0.181 .............. ............... *Evap. Refrig. Temp. = 40 F. Cond. Refrig. Temp. = 100 F. Suction Vapor Temp. *= 65 F. Liquid Temp. = 98 F. aBased on 1057 lb per sq in. (87 F) Condenser Pressure, and 85 F Liquid Temp, bBased on 40 F Temp. COBFF. OP Pehfor. 7.06 5.00 6.90 7.38 7.53 6.85 8.33 Ctclb Epp. PER CENT 84.8 46.9 82.9 88.8 90.4 82.3 100.0 - be removed. The cycle efficiency is the theoretical G. of P. divided by the ideal for the same temperatures. The cycle efficiency usually changes as the compression temperatures change. Comparative results of modified theoretical cycles of the refrigerants, are given in Table 7. \ . Practical Cycle . Fig. 3 illustrates the pressure-volume and temperature-entropy dia grams for an actual cycle. These diagrams are based upon the com pressor receiving vapor superheated and upon sub-cooling of the liquid going to the evaporator. The theoretical cycle is aibicc^ax. However, the vapor during compression actually follows line aj)z due to superheating as a result of the inefficient work of compression. The theoretical work of compression is ajticddi. Added to this ,is the area bibigihib-t on the tem perature-entropy diagram which represents the inefficient work of com pression (assuming no compressor heat losses). The sum of these areas represents the total work of the compressor per pound of refrigerant, and Chapter 2--Refrigeration the ratio of theoretical cycle work to the actual work represents the over all efficiency.. It should be noted that area aiWifiti is considered as part of the inefficient work and is commonly termed the superheat loss. The refrigerating effect per pound is. the same for the practical as for the theoretical cycle, working with the same sub-cooling of liquid and super heating of vapor, that is, area ejCigi/^i. . Sources of loss which are usually recognized as reflected by the overall efficiency referring particularly to reciprocating and rotary systems, are as follows: 1. The superheat loss. . 2. A pressure loss to and from the cylinder of the compressor. (The line pressure drop between the compressor and the evaporator and condenser, respectively, is usually taken into account separately in the design of the refrigeration system.) 3. Leakage loss through valves and past pistons is quite small in most compressors. 4. With an oil soluble refrigerant, there may be an absorption loss due to absorption and re-evaporation of refrigerant in the oil of the cylinder. 5. Mechanical losses are always present and are usually a large part of the total. Fig. 3. Practical Dichlorodifluoromethane (Fi2) Cycles Reciprocating and rotary compressors always take in less vapor than that which corresponds to the displacement. The overall volumetric efficiency is the ratio of the suction vapor volume to the piston displace ment. Part of this is the re-expansion volumetric efficiency which is the volume, at suction pressure, of the usefully re-expanded vapor which was in the clearance volume. This is expressed by the following equations: Volumetric Efficiency = 1-----X where = clearance volume. . I'd = cylinder displacement volume. . 45 . --1 andAmerican Society of Heating Ventilating Engineers Guide, 1936 The balance of the overall volumetric efficiency is known as the super heat volumetric efficiency even though it includes some other sources of capacity loss. .. The mechanical efficiency of a reciprocating and rotary compressor must be multiplied by the superheat volumetric efficiency to give the overall efficiency of the compressor. ' Eff. overall = ,^! Eff-overa" x Mech.Eff. = Super. Vol. Eff. X Mech. Eff. - Vol. ttl.reexp- , (7) Normally, the volumetric efficiency of a compressor varies with the Chapter 2--Refrigeration ired a two-stage purge is usually used,sometimes, a combination steamand water and occasionally a two-stage steam purge. The vapor which is drawn from the evaporator is the result of spraying water which has been warmed by the cooling load into the flash evaporator. Evaporation of a art of this water occurs, which cools the remainder, which is then again returned to the cooling load to receive more heat. The performance of the steam ejector may be studied theoretically by the use of the temperature-entropy diagram, Fig. 5. Unlike its usual application, however, the amount of working fluid is different for one portion of the cycle than for the other. Dry saturated steam under high pressure, for example 100 lb per square inch gage, at a, is expanded ratio of compression, while the mechanical efficiency remains virtually fixed. Good standard practices for Fi2 compressors are: Low comp, ratio = 2.5 to 1 . Vol eff.reexp. Vol. eff.super- Vol. eff-overall Mech. eff. 94 to 96 per cent 75 to 85 per cent 70 to 81 per cent 75 to 85 per cent High comp, ratio = 5 to 1 88 to 92 per cent 73 to 77 per cent 64 to 71 pier cent 75 to 85 per cent These values are for one ton or larger compressors. Part of the dif ference expresses the change with capacity.. With other refrigerants.and other types of compressors there will be some further variation. ; \ .- Steam Ejector Refrigeration System Fig. 4 is a diagrammatic representation of . a typical steam ejector refrigeration system. Live saturated steam is supplied to a nozzle which discharges at a high vacuum into the steam ejector. The expansion of the steam imparts a tremendous velocity to it, which entrains vapor from a flash evaporator and compresses it, with a conversion from velocity to static pressure. The mixture of vapor is then delivered to a condenser. The condensate is removed by suitable means, some of it being used in some cases to supply make-up water to the evaporator circuit. The con denser is maintained free of air by means of a suitable purge. This may. take the form of a water ejector if only a small amount of air is to be removed, as in a completely closed system. If a larger capacity is re- 46 Fig. 5. Steam Ejector Temperature-Entropy Diagram through the nozzle of the steam ejector. With 100 per cent efficiency, the expansion would occur along isentropic line ab. Actually, however; most nozzles are only about 90 per cent efficient, the real expansion being along the line abx. The resulting velocity is determined from the work area abxgea when multiplied by the mechanical efficiency. , At the evaporator pressure or slightly below, the vapor from the nozzle mixes with virtually dry saturated vapor from the evaporator. An impact loss also occurs at this point due to the mixture of vapors at different velocities. This results in bringing the state point of the mixture to c. Compression then occurs along the line cd, the work of compression per pound being cdfgc. In computing the work area, however, the point c is not actually known. Therefore, the work area CidfgCi is used in expres sing the efficiency of the ejector, the line cfd being an isentropic. The losses are expressed by nozzle efficiency, impact loss and diffuser efficiency. The work of compression, however, is performed on the mass of the mixture;. Thus, the available work is reduced in proportion to: 3/ primary . . . * M mixture1 , 47 of andAmerican Society Heating Ventilating Engineers Guide, 1936 ' The-impact loss is commonly determined from the formula: ' M Vprimary M ^secondary = ^mixture (8) Common, efficiencies for commercial ejectors are: nozzle efficiency 90 per cent, diffuser efficiency 60 to 70 per cent. Customary steam rates in pounds per ton are approximately as follows: Evaporator temp. Condenser temp. Evaporator temp. Condenser temp. 50 F 105 F 40 F 105 F Steam press. 100 lb Steam press Steam rate 30 1b per hour per ton Steam rate Steam press. 100 lb Steam press Steam rate 40 lb per hour per ton- Steam rate 12lb 45 lb per hour per ton. 12lb 70 lb per hour per ton. Chapter 2--Refrigeration Characteristics of Compression Systems The different types of compression systems have quite different characteristics of capacity and power with varying evaporator tempera ture and with varying condenser temperature, as will be seen from curves in Figs. 6 and 7. The capacity of the reciprocating and rotary compressor varies slowly with a change of evaporator temperature, and the variance of power requirements, in the air conditioning range of operation, is small for a change of evaporator temperature. On the other hand, the capacity and power of the centrifugal machine vary rapidly, and the capacity of the Fig. 6. Performance Characteristics of Compression Refrigeration " Machines at Constant Speed v ' Condenser Temperature 100 F . The steam ejector uses large amounts of condenser water and steam, and therefore this system has relative advantages when large quantities of water and steam are available at reduced costs. Characteristic curves show that the ejector performance is independent of condenser tempera ture up to a certain temperature, depending upon the particular design, and above this temperature the ejector breaks and loses all capacity. (See also Chapter 10.) . 48 Fig. 7. Performance Characteristics of Compression Refrigeration Machines at Constant Speed . Evaporator Temperature 40 F , steam ejector also varies considerably. Thus, both these latter types tend to be more nearly self-regulating than the reciprocating and rotary com pression type. On the other hand, the operating range of the latter near standard capacity is superior. Although the capacity of the reciprocating and rotary compressor is little affected by the condenser temperature, the power of the compressor is greatly affected, while the reverse is true for the centrifugal compressor. As previously , indicated, the condenser temperature has no effect on the capacity of the steam ejector type of compressor untiLa certain point is reached, beyond which the capacity is . zero. The steam consumption for the performance characteristic curves shown in Figs. 6 and 7 remains constant for all evaporator and condenser temperatures. .. of andAmerican Society Heating Ventilating . Engineers Guide, 1936 Fig. 8. Closed Absorption System Unconditioned Fig. 9. Open Liquid Adsorption System Fig. 10. Open Solid Material Adsorption System . 50 Chapter 2--Refrigeration CLOSED ABSORPTION SYSTEM Years ago the closed absorption system was in favor for industrial refrigeration and ice making. It is now of little commercial importance* however, except for very special applications (notably the gas-fired refrigerator). The most usual refrigerant has been ammonia, and in some cases water has been used as an absorbent. However, a long list of refrigerant-absorbent combinations have been proposed and quite a number have been tested, either experimentally or commercially. There are some commercial installations using a dry adsorber instead of a liquid absorber. . Fig. 8 shows a typical diagram of a closed absorption system. A mixture of refrigerant and absorbent is evaporated in the generator, passes to an analyzer and rectifier where it is purified, and then to a con denser where the refrigerant and remaining absorbent is condensed. It then passes through an expansion valve to an evaporator, where heat is absorbed from a cooling load. From the evaporator the vapor and residual absorbent passes to an absorber; where it meets absorbent which is initially low (weak) in refrigerant concentration. The absorbent absorbs the vapor, and the strong absorbent liquor is transferred to the generator through an interchanger with the weak liquor returning from the generator. . Cooling water is ordinarily used in the absorber to remove the heat of absorption and maintain the absorptive power of the absorber at a maximum. Like the steam ejector system, the absorption system compares most favorably when a cheap source of cooling water and steam or other heat source is available. Unlike the ejector system, the comparative per formance is usually best with a wide range of temperature between the evaporator and absorber, since with a good refrigerant-absorbent com bination, the amount of heat and water required for a given refrigerating effect increases slowly with an increase of evaporator-condenser tem perature range. . There are innumerable variations on the arrangement shown in Fig. 8 which include multiple absorption systems, parallel absorption systems,. systems using inert gas to raise the pressure in the evaporator and ab sorber to that of the condenser. OPEN ADSORPTION SYSTEMS For air conditioning installations, some experimental work and some commercial work has been done, using open adsorption refrigeration systems. The open liquid adsorption system is illustrated diagram matically by Fig. 9. Air from the outside and from the conditioned space is drawn through an adsorbent spray which,.with the air, is cooled by passing over water cooled surfaces. The adsorbent material adsorbs much of the water vapor from the air. The cooling coil removes the heat of adsorption and may cool the air below entering temperature, if. the water is cold. The dehumidified and partially cooled air is then passed to a humidifier where water-vapor is added with further cooling by evapora tion. A bypass may be provided so that some of the dry air bypasses the 51 of andAmerican Society Heating Ventilating Engineers Guide, 1936 humidifier in order to prevent the dew point of the mixture from rising too high. The air then passes through a fan and is delivered to the con ditioned space. The adsorbent, rich in water vapor, is discharged through an interchanger to a regenerator, from which it again flows to the adsorber. The adsorbent materials most commonly considered are solids which are put into solution as brines (see also Chapter 10). The difficulty with most adsorbents is that their adsorptive power is not great enough to dehumidify the air sufficiently. Thus, they have to be used inefficiently or do an inadequate job of dehumidification. Fig. 10 is a diagrammatic representation of an open solid material adsorption system. The spray and cooling coil of the open adsorber is replaced by a bed of adsorptive material and a separate water cooling coil, and a second section of adsorber must be provided for alternate reactiva tion while the first is adsorbing. A set of dampers or a rotary device must be arranged to connect the beds alternately to the air to be conditioned and to the hot gases for regeneration. Otherwise the liquid adsorption and solid adsorption systems are identical. The most efficient solid adsorption systems use some internal means of heating the adsorber bed before activation, and cooling it after activation, and other means may also be employed for improving the performance. These systems are especially affected by the temperature of the cooling water, since if the air leaving the cooling surface is at a higher temperature than the air entering, additional work must be done iii the generator or activator in order to compensate for the extra sensible heat of the leaving air. On the other hand, if the leaving temperature is lower than the entering temperature, the reverse is true. When the cooling water temperature is low, similar economies may, however, be obtained with compression systems by the use of an air pre-cooling coil. From this discussion it may be seen that these systems function to best advantage on a high air temperature, and on one in which the initial moisture content is high. Thus the use of high room temperatures and. comparatively large amounts of outside air are encouraged in connection with these systems. In order to offset the effect of high air temperature, some effort is made to keep the humidity lower than usual. The ratio of the heat input to the refrigerant Output, where the temperature of the air entering and leaving the adsorber cooler is not widely different, may vary from 4 to 1 for some of the solid adsorption systems, to as low as 1.5 to 1 for some of the liquid adsorption systems. THE REVERSE CYCLE The idea of heating by the reverse refrigeration cycle has captured the imagination of many people and has been much discussed. In principle, heat is absorbed in an evaporator from some available source of heat, pumped to a higher temperature and delivered to a cpndenser. The heat from the condenser is used for heating purposes. The compressor acts as a heat pump whose fundamental function is to raise the potential of the heat. The theoretical work of compression in relation to the heat delivered is: ' Tt . Ti - Tt 52 Chapter 2--Refrigeration where Xi = absolute temperature ofevaporator. Ti - absolute temperature of condenser. . - Thus with a small spread of temperature between the evaporator and the condenser, 6 or 8 times as much heat may be obtained theoretically and 4 or 5 times practically, as the work put in. There are a number of limitations, however, the most serious of which is the lack of ready availability of a practical source of heat. 1 Well water is the most desirable since its temperature is high even in the winter and thus a large amount of heat may be removed in relation to the weight of water handled. 2 Air may be used but its specific heat is low and its temperature uncertain. When the most heat is needed, the temperature of the air is lowest, thus resulting in the least favorable temperature combination. 3 It has been proposed to obtain heat by freezing water, but this is still in the theoretical stage. Some* of the other factors which act as limitations are the large tem perature spread when using air as a source of heat and when attempting to cool with even moderately low outside temperatures, the frequent dis parity between the size of the cooling load and heating ^ load requiring extra equipment for a complete heating load, and the relatively high initial cost of equipment at present available for the reverse cycle in comparison with that available for heating by conventional means. Because of these limitations, the present application of the system is largely limited to temperate climates, such as Florida and Southern California, or to heating only for intermediate seasons, or to other locali-. ties which have peculiar advantages as, for instance, the ready avail-, ability of well water. In these locations it is frequently possible, to do all' of the heating necessary with the refrigeration equipment so that the extra cost is only that of reversing the functions of the condenser and evaporator. . . PROBLEMS IN PRACTICE 1 Dichlorodifluoromethane (Fu) at a saturated temperature of 30 F but superheated 25 F to 55 F is compressed to a saturation temperature of 90 F with a compressor having an overall efficiency of 70 per cent. It leaves the con denser sub-cooled 5 F. What is the: a. Work per pound; b. Refrigerating effect; c. Pounds per minute per ton; d. Horsepower per ton; e. Heat rejected to condenser neglecting radiation;/. Equivalent discharge temperature? <* siix 43 16 x 144 x -939 x m -1 ] x aw - 9000 (By Pressure--Volume Method). ' . Check: (93.35 - 85.25) X ~, = 11.6 Btu per pound = 9000 ft-lb. (By Heat Content Method). b. 95.25 -- 27.48 = 57.77 Btu per pound. 53 ' of andAmerican Society Heating Ventilating Engineers Guide, 1936 c. -- 3.46 lb per minute per ton. ' d. 9000 X = 0.944 hp per ton. e. 200 + 0.944 X 42.5 => 240 Btu per minute per ton. . Check:. Heat content leaving compressor = 85.25 + 11.6 = 96.85 (96.85 -- 27.48) 3.46 = 240 Btu per minute per ton. /. Heat Content = 96.85. ` ' Pressure = 114.31b per square inch.. From Table 3, Temp. = 146 F. 2 If the velocity of vapor in the suction pipe is'50 fps and there are 10 velocity heads lost between evaporator and compressor, what is the saturation tem perature at the evaporator? .. h = 10 X. (4j)2 = 388 ft head. Head per degree = (47.28 - 43.16) X (M63 i-:79g) X ^ = 98.4 ft. Check: Head per degree = 9000 X (99 ^gp) = 105 ft- (Approx.) OOO Temperature = 30 + -- = 34 F. .3 If the refrigerant is sub-cooled to 70 F, what is the'effect on: a. Work per pound: b. Refrigerating effect; c. Horsepower per ton? a. No effect on work per pound. b. (85.25 - 23.90) = 61.35. 61.35 -- 57.77 = 3.58 Btu increase. 3 58 ,, 0 ,,. gy - b.2 per cent increase. 200 c. 61.35 = 3.27 lb per minute per ton. 3.27 9000 X 33,000 = 0 891 hp per ton' 0.944 -- 0.891 = 0.053 hp decrease. 5.6 per cent decrease. 4 What is the approximate change in capacity of the following types of systems per degree at 40 F: a. Reciprocating; b. Centrifugal; c. Ejector? a. 2.5 per cent. b. 3.0 per cent. c. 7.5 per cent. 54 Chapter 2--Refrigeration , 5* b ' Which type of system will maintain the most uniform evaporator temperature with change of load? Which system will maintain the most uniform load with change of evaporator temperature? ' From Fig. 6. a. Steam ejector. b. Reciprocating and rotary. 6 % a.' What is the velocity of steam expanding from 100 lb per square inch e ' saturated to 0.0178 lb per square inch absolute, corresponding to 50 F if the nozzle has an efficiency of 90 per cent? j What is the velocity of the mixture of this steam with one-third the mass "of entrained steam moving at 300 fps? ' a. v = .' V = 4110 fps. b. Vjnix' 3 X 4110 + 1 X 300 = 3158fps, 4 . ^ ^ jf a;r entering an open adsorption system at 80 F and 50 per cent relative humidity is dehumidi6ed and cooled to a temperature of 90 F and 12 per cent relative humidity, how much air is cooled per ton of refrigeration and what is the latent heat of the water which is adsorbed? Entering Conditions 66.6 F WB. 30.85 Btu Total, Heat 76.0 Grains per Pound Leaving Conditions 59.1 F WB. 25.59 Btu Total Heat 24.5 Grains per Pound cfm 200 X 13.5 = 513 cfm per ton. (30.85 - 25.59) 513 X (760 - 24.5) X 1044 13.5 X 7000 292.5 Btu. <513 X 0.2415 X 10's Check: L -- 200 + t 13.5 ) 291.6 Btu. . 8 If air entering an open adsorption system at 80 F and 50 per cent relative humidity is cooled to 75 F and 12 per cent relative humidity, how much air is required per ton and what is the latent heat of the water which is absorbed? Entering Conditions 66.6 F WB 30.85 Btu Total Heat 76.0 Grains per Pound Leaving Conditions 50.3 F WB 20.35 Btu Total Heat 14.4 Grains per Pound cfm 200 X 13.5 (30.85 - 20.35) 257 cfm per ton. 257 X (76.0 - 14.4) X 1044 13.5 X 7000 175.2 Btu. Check: L = 200 - ( ^ * ^j15 X 5) = 177.0 Btu. 9 0 Why is it possible for a reversed cycle refrigeration unit to show a better performance in heating operation than when operating during the cooling season? of and 1936American Society Heating Ventilating Engineers Guide, In normal use a refrigerating machine is arranged to remove heat and the heat removed is thrown away. The driving energy is converted into heat, most of which is added'to the heat removed and is also thrown away. In the reversed refrigeration cycle the heat removed is not thrown away, but, together with the heat converted from the driving energy, it is utilized to heat the building. 10 In a.large ice plant, for approximately 147,000 Btu equivalent input to the motor driving the ammonia compressor a ton of ice is produced, in the pro duction of which 288,000 Btu are removed from one ton of water at 32 F to transform it to ice at 32 F. What is the ratio of the heat removed in this process to the input of the motor? ' In this case the heat removed, or pumped from the water to the air is approximately 1.96 times the heat equivalent of the input to the motor. : 11 If the cycle is reversed in Question 10 and the heat is transferred or pumped from the air to the water, what is the ratio of the heat removed in the process to the motor input? In this case 2.96 Btu is put into the water for each Btu equivalent input to the motor, for the total heat put into the water now represents the heat pumped plus the heat converted from the driving energy, or motor input. vs,. \ 56 Chapter 3 VENTILATION AND AIR CONDITIONING STANDARDS Vitiation of Air, Heat Regulation in Man, Effects of Heat, Effects of Cold, Temperature Changes, Acclimatization, Warmth and Comfort, Effective Temperature, Comfort Chart, Comfort Line, Comfort Zone, Application of Comfort Chart, A.S.H.V.E. Ventilation Standards, Natural and Mechanical Ventilation, Recirculation, Ultra-Violet Radiation and Ionisa tion, Heat and Moisture Losses VENTILATION is defined in part as "the process of supplying or removing air by natural or mechanical means to or from any space." (See Chapter 44.) The word in itself implies quantity but not necessarily quality. From the standpoint of comfort and health, however, the problem is now considered to be one of securing air of the proper quality rather than of supplying a given quantity. . The term air conditioning in its broadest sense implies control of any or all of the physical or chemical qualities of the air. More particularly, it includes the simultaneous control of temperature, humidity, movement, and purity of the air. The term is broad enough to embrace whatever other additional factors may be found desirable for maintaining the atmosphere of occupied spaces at a condition best suited to the physio logical requirements of the human body. , VITIATION OF AIR Under the artificial conditions of indoor life, the air undergoes certain physical and chemical-changes which are brought about by the occupants themselves. The oxygen content is somewhat reduced, and the carbon dioxide slightly increased by the respiratory processes. Organic matter, which is usually perceived as odors, comes from the nose, mouth, skin and clothing. The temperature of the air is increased by the metabolic processes, and the humidity raised by the moisture emitted from the skin and lungs. Moreover, according to latest researches1, there is a marked decrease in both positive and negative ions in the air of occupied rooms. Contrary to old theories, the usual changes in oxygen and carbon dioxide are of no physiological concern because they are much too small even under the worst conditions. The amount of carbon dioxide in air is often used in ventilation work as an index of odors of human origin, but *See A.S.H.V.E. research paper entitled 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. Trans actions. Vol. 37, 1931). 57 --- ----------------------------------------------------------------------------------------------------------------------------------- -- - of and 1936American Society Heating Ventilating Engineers Guide, i>|.] ' the information it affords rarely justifies the labor involved in making the observation2. Little is known of the identity and physiological effects of the organic matter given off in the process of respiration. The former belief that the discomfort experienced in confined spaces was due to some toxic volatile matter in the expired air is now limited, in the light of numerous researches, to the much less dogmatic view that the presence of such a substance has not been demonstrated. The. only certain fact is that expired and transpired air is odorous and offensive, and it is capable of producing loss of appetite and a disinclination for physical activity, These reasons alone, whether aesthetic or physiological, are sufficient to warrant a desire for proper air conditions. .. A certain part of the dissemination of disease which occurs in confined spaces is caused by the emission of pathogenic bacteria from infected persons. Infections by droplets from coughing and sneezing constitute a limited mode of transmission in the immediate vicinity of the infected person. Experiments have shown that the mouth spray is a coarse rain which settles down quickly. The contamination is local and the problem is considered to be largely one of contact infection rather than air-borne infection. The primary factors in air conditioning work, in the absence of any specific contaminating source, are temperature, humidity, air movement and body odors. As compared with these physical factors, the chemical factors are, as a general rule, of secondary importance. ' j i j i j i . HEAT REGULATION IN MAN The importance of temperature, humidity and air movement arises from the profound influence which these factors exert upon body tem perature, comfort and health. Body temperature' is a resultant of the balancing action between its heat production and its heat loss. The heat resulting from the combustion of food within the body maintains its temperature well above that of the surrounding air. At the same time, heat is constantly lost from the body by radiation, conduction 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. In healthy persons this takes place auto matically by the action of the heat regulating mechanism. According to the general view, ^pecial areas in the skin are sensitive to temperature. Nen e courses carry the sense impressions to the brain and the response comes back over another set of nerves, the motor nerves, to the musculature and to all the active tissues in the body, including the endocrine glands. In this way, a two-sided mechanism controls the body temperature by (1) regulation of internal heat production (chemical regulation), and (2) regulation of heat loss by means of automatic varia tion in the rate of cutaneous circulation and the operation of the sweat glands (physical regulation). The-mechanisms of adjustment are complex and little understood at the present time. Coordination of these dif ferent mechanisms seem to vary greatly with different air conditions. 'Indices of Air Change and Air Distribution, by F. C. Houghten and J. L. Blackshaw (A.S.HVE Transactions, Vol. 39. 1933). 58 ----------------- Chapter 3___ Ventilation and Air Conditioning Standards With rising air temperatures up to 75 F or 80 F, metabolism, or internal . J! oroduction, is decreased5, probably by an inhibitory action on heat oducing organs, especially the adrenal glands, which seem to exert the pr . influence on basic combustion processes in the body. The blood "amllaries in the skin become dilated by reflex action of the vasomotor erves allowing more blood to flow into the skin, and thus increase its temoerature and consequently its heat loss. The increase in peripheral circulation is at the expense of the internal organs. If this method of cooling is not in itself sufficient, the stimulus is extended to the sweat elands which allow water to pass through the surface of the skin, where it is evaporated. This method of cooling is the most effective of all, as long as the humidity of the air is sufficiently low to allow for evaporation. In high humidities, where the difference between the dew-point temperature of the air and body temperature is not sufficient to allow rapid evapora tion, equally good results may be obtained by increasing the air move ment, and hence the heat loss by conduction and evaporation. In cold environments, in order to keep the body warm there is an actual increase in metabolism brought about partly by voluntary muscular con tractions (shivering) and partly by an involuntary reflex upon the heat producing organs. The surface blood vessels become constricted, and the blood supply to the skin is curtailed by vasomotor shifts to the internal organs in order to conserve body heat. EFFECTS OF HEAT Although the human organism is capable of adapting itself to variations in environmental conditions, its ability to maintain heat equilibrium is limited. The heat regulating center fails, for instance, if the external temperature is so abnormally high that bodily heat cannot be eliminated as fast as it is produced. Part of it is retained in the body, causing a rise in skin and deep tissue temperature, an increase in the heart rate, and accelerated respiration. (See Table 1.) In extreme conditions, the metabolic rate is markedly increased owing to the excessive rise in body temperature4, and a vicious cycle results which may eventually lead to serious physiologic damage. Examples of this are met with in unusually hot summer weather and in hot industries where the radiant heat from hot objects renders heat loss from the body by radiation and convection impossible. Consequently, the workers depend entirely on evaporation for the elimination of body heat. They stream with perspiration and drink liquids abundantly to replace the loss. One of the most deleterious effects of high temperatures is that the blood is diverted from the internal organs to the surface capillaries, in order to serve in the process of cooling. This affects the stomach, heart, lungs and other vital organs, and it is believed that the feeling of lassitude and discomfort experienced is due to the anaemic condition of the brain. Heat and Moisture Losses From the Human Body and Their Relation to Air Conditioning Problems, by F. C. Houghten, W. W. Teague, W. E. Miller, and W. P. Yant (A.S.H.V.E. Transactions, Vol. 35, 1929, p. 245). Thermal Exchanges Between the Human Body and Its Atmospheric Environment, by F. C. Houghten, W. W. Teague, W. E. Miller, and W. P. Yant (The American Journal of Physiology, Vol. 88. No. 3. April, 59 American Society of. Heating and Ventilating Engineers Guide, 1936 Table 1. Physiological Responses to Heat of Men at Rest and at Work? Eppective Temp. Actual Cheek T(Demsap Fahr) 60 70 80 85 90 95 100 105 110 ___ -- 96.1 96.6 97.0 97.6 99.6 104.7 -- Men at Rest Men at Work 90,000 pt-lb op Work per Hour . Rise in Rectal Temp (Deg Fahr per Hoar) Increase in Pulse Rate (Beats per Min per Hour) Approximate DssinBody Weight by Perspiration (Lb per Hr) Total Work Accomplished (Ft-lb) Rise in Body Temp (Deg Fahr per Hr) Increase in Pulse Rate (Beats per Min per Hr) Approximate Lass in Body Wt. by Per spiration (Lb per Hr) . 0.0 0.0 0.1 0.3 0.9 2.2 4.0 5.9b 6 0 i 4 15 40 83 137b 0.2 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 4.0 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 2.7 3.5b 4.4b "Data by A.S.H.V.E. Research Laboratory. ^Computed value from exposures lasting less than one hour. The'stomach loses some of its power to act upon the food, owing to a diminished secretion of gastric juice, and there is a corresponding loss in the antiseptic and antifermentive action which favors the growth of bacteria in the intestinal tract6. These are considered to be the potent factors in the increased susceptibility to gastro-intestinal disorders in hot summer weather. The victim may lose appetite and suffer from indiges tion, headache and general enervation, which may eventually lead to a premature old age. ' . In warm atmospheres, particularly during physical work, a considerable amount of chloride is lost from the system through sweating. The loss of this substance may lead to attacks of cramps, unless the salts are replaced in the drinking water. In order to relieve both cramps and fatigue, Moss6 recommends the addition of 6 grams of sodium chloride and 4 grams of potassium chloride to a gallon of water. 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 clearly that physical work in warm atmospheres is a great effort, and that production falls progressively as the temperature rises. The incidence of industrial accidents reaches a minimum at about 68 F, increasing above and below that temperature. Sickness and mortality rates increase progressively as the temperature rises. EFFECTS OF COLD The action of cold on human beings is not well known. Cold affects the human organism in two ways: (1) through its action on the body-as a whole, and (2) through its action on the mucous membranes of the upper respiratory tract. Little exact information is available on the latter. On exposure to cold, the loss of heat is increased considerably and only `Influence of Effective Temperature upon Bactericidal Action of Gasto-Intestinal Tract, by Arnold and Brody (Proceedings Society Exp. Biol. Med. Vol. 24. 1927, p. 832). , Some Effects of High Air Temperatures upon the Miner, by K. N. Moss (Transactions Institute of Mining Engineers, Vol 66, 1924, p. 284). 60 Chapter 3___Ventilation and Air Conditioning Standards within certain limits is compensation possible by increased heat produc tion and decreased peripheral circulation. The rectal temperature often rises upon exposure to cold but the pulse rate and skin temperature fall. The blood pressure increases, owing to constriction in the peripheral vessels and to thickening of the blood. The subcutaneous tissues and muscles form reservoirs for storing the water which leaves the blood. In extremely cold atmospheres compensation becomes inadequate. The body temperature falls and the reflex irritability of the spinal cord is markedly affected. The organism may finally pass into an unconscious state which ends in death. Cannon showed that excessive loss of heat is associated with increased activity of the adrenal medulla7. The extra output of adrenin hastens heat production which protects the organism against cooling. Bast8 r of thvroid and adrenal elands UDon exposure to cold. Effects of Temperature Changes A moderate amount of variability in temperature is known to be beneficial to health, comfort, and the performance of physical and mental work. On the other hand, extreme changes in temperature, such as those experienced in passing from a warm room to the cold air out of doors, appear to be harmful to the tissues of the nose, and throat which are the . portals for the entry of respiratory diseases. Experiments show that chilling causes a constriction of the blood vessels of the palate, tonsils and throat, which is accompanied by a fall in the temperature of the tissues. On rewarming, the palate and throat. do not always regain their normal temperature and blood supply. This anaemic condition favors bacterial activity and it is believed to play a part in the inception of the common cold and other respiratory diseases. It is believed, that the lowered resistance is duo. to a diminution in the number andphagocytic activity of :the.leucocytes,-'(white blood cells) brought about by exposure to coid and by changes in temperature. Sickness records in;industries,'seem -tc strengthen this belief. The Industrial Fatigue Research Board' of' England9 found that in workers exposed to high temperatures qjicb,to changes in temperature, namely, steel melters, puddlers, and tiri-piatle millmen, there is an excess of all sickness, the excess among the puddlers being due chiefly to respiratory diseases and rheumatism. The causative factor was not the heat itself but the sudden changes in temperature to which the workers were exposed. The tin-plate millmen who were not exposed to chills, since they work almost continuously throughout the shift, had no excess of rheumatism and respiratory diseases. On the other hand, the blast-fumacemen, who work mostly in the open, showed more respiratory sickness than the steel workers. This experience in British factories is well in accord with the findings in American industries10. According to these data the highest Studies on the Condition of Activity of Endocrine Glands, by W. B. Cannon, A. Guerido, S. W. Britton and E. M. Bright (American Journal of Physiology, Vol. 79, 1926, p. 466), . Studies in Exhaustion Due to Lack of Sleep, by T. H. Bast, J. S. Supernaw, B. Lieberman and J. Munro (American Journal of Physiology, Vol. 85, 1928, p. 135). - Fatigue and Efficiency in the Iron and Steel Industry, by H. M. Vernon (Industrial Fatigue Research Board, Report No. 5, 1920, London). . "Iron Foundry Workers Show Highest Percentage of Deaths from Pneumonia (Statistical Bulletin, Metropolitan Life Insurance Company, 1928). 61 of andAmerican Society Heating Ventilating Engineers Guide, 1936 pneumonia death rate is associated with dust, extreme heat, exposure to cold, and to sudden changes in temperature. ACCLIMATIZATION Acclimatization and the factor of psychology are two important in fluences in air conditioning which cannot be ignored. The first is man's ability to adapt himself to changes in air conditions; the second is an intangible matter of habit and suggestion. Some persons regard the unnecessary endurance of cold as a virtue. They believe that the human organism can adapt itself to a wide range of air conditions with no apparent discomfort or injury to health. In the light of the present knowledge of air conditioning these views are not justified. Acclimatization to extreme conditions involves a strain upon the heat regulating system and it interferes with the normal physiologic functions of the human body. Thousands of years in the heat of Africa do not seem to have acclimatized the Negro to a temperature averaging 80 F. The same holds true of northern races with respect to cold, although the effects are mitigated by artificial control. All this seems to indicate that adaptation to a climate averaging between 60 and 80 F is a very primitive trait11. ' Within these limits, however, there does occur a definite adaptation to external temperature level. People and animals raised under conditions of tropical moist heat have a lower rate of heat production than do those who grow up in cooler environments. This causes them to stand chilling poorly as they are unable to quickly increase internal combustion to keep up the body temperature. For this reason they have trouble standing the cold, stormy weather of the temperate' zones, and when exposed to it are very susceptible to respiratory infections. Likewise, people living in cool climates suffer greatly in the ipoist heat, of .the tropics until their adrenal activity has slowed- down.. "Within a couple' df years, however, they find themselves standing the Heat'much better arid disliking cold. They become acclimated by a definite change in the combustion level within the body12. ' - In certain individuals the psychologic factor is more powerful than acclimatization. A fresh air fiend may 'suffer in a room with windows closed regardless of the quality of the air. As a matter of fact, instances . are known in which paid subjects refused to stay in a windowless but properly conditioned experimental chamber because the atmosphere felt suffocating to them upon entering the room. . WARMTH AND COMFORT The temperature, humidity, and motion of the air, and the radiation between a person and surrounding hot or cold surfaces, taken together, determine his feeling of warmth and influence his elimination of body heat. In other words, the temperature sensations of the human body depend not only on the temperature of the surrounding air as registered by a dry-bulb thermometer, but also upon the temperature indicated by "Civilisation and Climate, by Ellsworth Huntington, Yale University Press, 1924. "Air Conditioning in its Relation to Human Welfare, by C. A. Mills, M.D. (A.S.H.V.E. Transactions, Vol. 40. 1934). 62 Chapter 3___Ventilation and Air-Conditioning Standards Wet-bulb thermometer. Dry air at a relatively high temperature may feel cooler than air of considerably lower temperature with a high mois ture content. Air motion makes any moderate condition feel cooler. On the other hand, in cold environments an increase in humidity produces a cooler sensation. The dividing line at which humidity has no effect upon comfort varies with the air velocity and is about 46 F (drybulb) for still air and about 51, 56 and 59 F for air velocities of 100, 300 and 500 fpm, respectively. ' Thermo-Equivalent Conditions Combinations of temperature, humidity and air movement which pro duce the same feeling of warmth are called thermo-equivalent con ditions. A series of tests18- M- 15 has been carried out in the psychrometric rooms of the A.S.H.V.E. Research Laboratory, Pittsburgh, in order to determine the equivalent conditions met with in general air conditioning work. These show that this newly-developed scale of thermo-equivalent conditions not only indicates the sensation of warmth, but also determines the physiological effects on the body induced by heat and cold. For this reason, it is called the effective temperature scale or index. Effective temperature is an index of warmth or cold. It is not in itself an index of comfort, as it is often assumed to be, nor are the effective tem perature lines necessarily lines of equal comfort. This is true because, in determining this index, the subjects compared not the relative comfort, but rather the relative warmth or cold of various air conditions. Moist air at a comparatively low temperature, and dry air at a higher tempera ture may each feel as warm as air of an intermediate temperature and humidity, but the comfort experienced in the three air conditions would be different, although the effective temperature is the same. Under extreme humidity conditions there seems to be a difference be tween sensations of absolute comfort and of the proper degree of warmth. In other words, human beings are not necessarily comfortable when the air is neither too warm nor too cold. Air of proper warmth may, for in stance, contain excessive water vapor, and in this way interfere with the normal physiologic loss of moisture from the skin, leading `to damp skin, and clothing and producing more or less discomfort; or the air may be excessively dry, producing appreciable discomfort to the mucous mem brane of the nose and to the skin which dries up and becomes chapped from too rapid loss of moisture. According to the comfort experiments first conducted at the A.S.H.V.E. Laboratory18 in the U. S. Bureau of Mines, Pittsburgh, and later studies at the Harvard School of Public Health17 in Boston, effective temperature appears to be a fair index of comfort also, particularly within a humidity range of 30 to 60 per cent, approximately. "Determining Lines of Equal Comfort, by F. C. Houghten and C, P. Yagloglou (A.S.H.V.E. Trans actions, Vol. 29, 1923, p. 361). "Cooling Effect on Human Beings by Various Air Velocities, by F. C. Houghten and C. P. Yagloglou (A.S.H.V.E. Transactions. Vol. 30, 1924, p. 193). . "Effective Temperature with Clothing, by C. P, Yagloglou and W. E. Miller (A.S.H.V.E. Trans actions, Vol. 31, 1925, p. 89). . "Determination of the Comfort Zone With Further Verification of Effective-Temperatures Within This Zone, by F. C. Houghten and C/P. Yagloglou (A.S.H.V.E. Transactions, Vol. 29. 1923. p. 361). "The Summer Comfort Zone; Climate and Clothing, by C. P. Yaglou and. Philip Drinker (A.S.H.V.E. Transactions, Vol. 35. 1929). . 63 American Society of Heating and Ventilating Engineers Guide, 1936 Definition of Effective Temperature . Briefly, effective temperature may be defined as an arbitrary index of the degree of warmth or cold felt by the human body in response to tempera ture, humidity, and movement of the air. Effective temperature is not a true temperature of the air but an index which combines temperature, humidity and air motion in a single value. The numerical value of the Chapter 3--Ventilation and Air Conditioning Standards signifies the minimum air movement it was possible to obtain in the" Laboratory s psychrometric chamber. Actually, the air motion was between 15 and 25 fpm in all experiments, without qualification, as measured by the Kata thermometer. This was not a linear movement of K-t >> rcnresented the turbulence or eddy currents produced by the air effective temperature index for any given air condition is fixed by the temperature of saturated air which, at a velocity or turbulence of 15 to 25 fpm, induces a sensation of warmth or cold like that of the given condition. Thus, any air condition has an effective temperature, of 65 deg when it induces a sensation of warmth like that experienced in practically still air at 65 F saturated with moisture. < In all reports of the A.S.H.V.E. Research Laboratory, the term still air ' 64 uiv Mia jo QNnoa toa Samson jo snwso change. Even in tightly sealed rooms, the natural air movement is not likely to fall below 10 fpm so long as there is a temperature or pressure difference between the air inside and that outside the room. The relation of temperature and humidity to comfort for persons normally clothed and at rest in still air is given in Fig. 1, while the effect of various air motions upon comfort for persons normally clothed at rest for velocities of 100 and 300 fpm are given in Figs. 2 and 3. The difference 65 American Society of Heating and Ventilating Engineers Guide, 1936 between the effective, temperature for still air and for moving air, of any velocity, represents the cooling resulting from that air velocity. These charts apply to average normal and healthy persons adapted to American living and working conditions. They are limited to sedentary or light muscular activity, and to rooms heated by the usual American convection methods (warm air, central fan and direct hot water and steam heating Chapter 3--Ventilation and Air Conditioning Standards If an occupant of a room loses heat by radiation to large wall or glass surfaces at lower temperatures, the air within the room must be main tained at a higher temperature to compensate for this effect in order to give the same feeling of warmth. The results of a recent study18 by the A.S.H.V.E. Laboratory, shown in Fig. 4, indicate that in poorly insulated buildings this effect may become of considerable importance. Thus an occupant of a room having inside wall surface temperatures of 55 F on three sides will require an air temperature of 74 F to have the same feeling of warmth he would experience in a warm-wall room with air at 70 F. A systems) in which the difference between the air and wall surface tem peratures may not be great. The charts do not apply to rooms heated by radiant methods such as the British panel system, open coal fires, and the like. They will probably not apply with adequate accuracy to races other than the white or perhaps to inhabitants of other countries where'the living conditions, climate, heating methods, and clothing are materially different from those of the subjects employed in experiments at the Research Laboratory. 66 30Temperatures Indicated by Shielded Thermometers in. Above the Floor wall consisting of 8-in. brick and plaster, with 16 F outside air tempera ture and 70 F inside air temperature, will have an inside surface, tem perature of 55 F. The reverse effect will be experienced by occupants of rooms having extensive high-temperature surfaces in them. In such cases, a lower air temperature is required to compensate for heat radiated to the occupant. The effective temperature index for persons doing medium or heavy muscular work, in still air, has also been determined at the A.S.H.V.E. Research Laboratory19. OPTIMUM AIR CONDITIONS No single comfort standard can be laid down which would meet every heed. There is an inherent individual variation in the sensation of, "Cold Walls and Their Relation to the Feeling of Warmth, by F. C. Houghten and Paul McDermott (A.S.H.V.E. Journal Section. Heating, Piping and Air Conditioning, January. 1933. p. 53). "Effective Temperature for Persona Lightly Clothed and Working in Still Air, by F. C. Houghten. W. W. Teague abd W. E. Miller (A.S.H.V.E. Transactions, Vol. 32, 1926). 67 , ofAmerican Society Heating and Ventilating Engineers Guide, 1936 warmth or comfort felt by persons when exposed to an identical atmos pheric condition. The state of health, age, sex, clothing, activity, and the degree of acquired adaptation seem to be the important factors affecting the comfort standards. Since the prolonged effects of temperature, humidity and air move ment on health are not known to the same extent as their effects on com fort, the optimum conditions for health may not be identical with those for comfort. On general physiologic grounds, however, the two do not How to Use the Effective Temperature Index and Comfort Charts (A.S.H.V.E. Transactions, VoJ. 38. 1932). 68 Chapter 3---Ventilation and Air Conditioning Standards d ffer greatly since this is in accordance with the efficient operation of the heat regulating mechanism of the body. This belief is strengthened by results of studies on premature infants over a four-year period20. By diusting the temperature and humidity so as to stabilize the body tem perature of these infants, the incidence of diarrhoea and mortality was decreased, gains in body weight increased and infections were reduced to a minimum. Comfort Chart; Comfort Line; Comfort Zone Fig. 5 shows a comfort chart, developed at the A.S.H.V.E. Laboratory, on which the average and extreme comfort zones have been superimposed. The extreme comfort zone includes air conditions in which one or more of the experimental subjects were comfortable. The average comfort zone includes those air conditions in which the majority of the subjects (50 per cent or more) were comfortable. That particular effective temperature at which the maximum number of subjects was comfortable was called . the comfort line. - The average winter comfort zone as determined at the A.S.H.V.E. Laboratory ranges from 63 deg to 71 deg ET (effective temperature). In winter while at rest, a large percentage of persons normally clothed were found to be comfortable at 66 deg ET and this temperature has been accepted by a committee of the Society21 as the winter comfort line or optimum effective temperature. The comfort line separates the cool air conditions to its left from the warm air conditions to its right. Under the air conditions existing along or defined by the comfort line, the body is able to maintain thermal equilibrium with its environment with the least conscious sensation to the individual, or with the minimum phsyiologic demand on the heat regulat ing mechanism. This environment involves not only the condition of the air with respect to temperature and humidity, but also the condition of the surrounding objects and wall surfaces. The comfort zone tests were made in rooms with wall surface temperatures approximately the same as the room dry-bulb temperature. For walls of large area having unusually high or low surface temperatures, however, a soiriewhat lower or higher- . range of effective temperature is required to compensate for the increased gain or- loss of heat to or from the body by radiation22. The average summer comfort zone for exposures of 3 hours or more ranges from about 66 deg to 75 deg ET, based on studies made at the Harvard School of Public Health17. The probable optimum effective temperature (for exposures of 3 hours or more) is 71 deg. These effective temperatures average about 4 deg higher than those found in winter when customary winter clothing was worn. The variation from winter to summer is probably due partly to adaptation to seasonal weather and partly to differences in the clothing worn in the two seasons. The best effective temperature (for exposures lasting 3 hours or more) was found to follow the average monthly outdoor temperature more closely than the prevailing outdoor temperature. It remained at approxi- "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). i ?9p{d Walls and Their Relation to the Feeling of Warmth, by F. C. Houghten and Paul McDermott (A.S.H.V.E. Transactions, Vol. 39, 1933). ;; 69 of andAmerican Society Heating Ventilating Engineers Guide, 1936 mately the same value in July, August and September, and although the average monthly temperature did not vary much-, the prevailing outdoor temperature ranged from 70 F to 99.5 F. A decrease in the optimum temperature became apparent only when the prevailing outdoor tempera ture fell to 66 F, which is below the customary room temperature in the United States for summer and winter. Young men as a general rule prefer conditions in the cool region of the comfort zone, and women and older people in the warm region of the comfort zone. Crowding the experimental chamber lowered the optimum effective temperature from 70.8 deg when the gross floor area per occupant was 44 sq ft and the air space 380 cu ft, to 69.4 deg when the floor area was reduced to 14 sq ft and the air space to 120 cu ft per occupant. In the comfort zone experiments of the A.S.H.V.E. Research Labora tory,the relative humidity was varied between the limits of 30 and 70 per cent approximately, but the most comfortable range has not been deter mined. In similar experiments at the Harvard School of Public Health, a relative humidity of 70 per cent was found to be somewhat humid in winter, by. about half of the subjects who were stripped to the waist, even when the dry-bulb temperature was 70 F or less. In summer, a relative humi dity of 30 per cent was pronounced as a little tod dry by about a third of the subjects wearing warm-weather clothing. So long as the temperature was kept within proper limits, the majority of the subjects were unable to detect sensations of humidity (i.e., too high, too low, or medium) when the relative humidity was between 30 and. 60 per cent. This is in accord with studies by Howell23, Miura24 and others. Dry air produces an excessive loss of moisture from the skin and respira tory tract. Owing to the cooling effect of evaporation, higher tempera tures are necessary, and this condition leads to discomfort and lassitude. Moist air, on the other hand, interferes with the normal.evaporation of moisture from the skin, and again may cause a feeling of oppression and lassitude, especially when the temperature is also high. Just what the optimum range of humidity is, is a matter of'conjecture. There seems to exist a general opinion, supported by some experimental and statistical data, that warm, dry air is less pleasant than air of a , moderate humidity, and that it dries up the mucous membranes in such a way as to increase susceptibility to colds and other respiratory dis- orders25- 26- 27. . For the premature infant, a high relative humidity of about 65 per cent is demonstrably beneficial to health and growth28, and according to Huntington29, this seems to be the case for adults also. All of these "Humidity and Comfort, by W. H. Howell (The Science Press, April, 1931). "Effect of Variation in Relative Humidity upon Skin Temperature and Sense of Comfort, by U. Miura (American Journal of Hygiene, Vol. 13, 1931. p.'432). . v "Reactions of the Nasal Cavity and Post-Nasal Space to Chilling of the Body Surface, by MuddrStuart, et aJ (Journal Experimental Medicine, 1921, Vol. 34, p. 11). ' "Reactions of the Nasal Cavity and Post-Nasal Space to Chilling of the Body Surfaces, by A. Goldman, ' et a! and Concurrent Study of Bacteriology of Nose and Throat (Journal Infectious Diseases, 1921, Vol. 29. p. 151). j _ . "The Etiology of Acute Inflammations of the Nose. Phhryna and Tonsils, by Mudd, Stuart, et al (Am. Otol.. Rhino!., and Laryngol., 1921). , "*' "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). . "Weather and Health, by Ellsworth Huntington (Bulletin of the National Research Council No. 75. -The National Academy of Science, Washington. D. C., 1930). -. 70 Chapter 3--viimu-w ~-------------------------------------------------------------- i______________ ,. indicate that the optimum humidity must always be considered ^combination with temperature. Until more exact information is secured, it would be desirable to restrict the comfort zones to the range of relative humidity employed in the ^"rnfort zone experiments, namely, 30 to 70 per cent. Relative humidities blow 30 per cent may prove satisfactory from the standpoint of comfort, 6 long as extremely low humidities are avoided. From the standpoint of health however, the consensus seems to favor a relative humidity between 40 and 60 per cent. In mild weather such comparativ ely high relati- e humidities are entirely feasible, but in cold or sub-freezing weather they are objectionable on account of condensation and frosting oh the windows. They may even cause serious damage to certain building materials of the exposed walls by condensation and freezing of the moisture accumulating inside these materials. Unless special precautions are taken .to properly insulate the affected surfaces, it will be necessary to reduce the degree of artificial humidification in sub-freezing weather to less than 40 per cent, according to the outdoor temperature. Information on the prevention of condensation on building surfaces is given in Chapter 7. The principles underlying humidity requirements and limitations are discussed more fully elsewhere30. The comfort chart (Fig. 5) applies to. adults between 20 and 70 yearsi of age living in the northeastern parts of the United States. For pre maturely born infants, the optimum temperature varies from 100 F to 75 F, depending upon the stage of development. The optimum relative humidity for these infants is placed at 65 per cent. 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 F to 68 F with natural indoor humidi ties. For school children, the studies of the New York State Commission- on Ventilation place the optimum air conditions at 66 F to 68 F tempera ture with a moderate humidity (not specified) and a moderate but not excessive amount of air movement (not specified)81. Satisfactory comfort conditions are found to vary from 40 deg to 70 deg ET, depending upon the rate of work and amount of clothing worn- The effective temperatures giving maximum comfort for persons working have been determined by the A.S.H.V.E, Research Laboratory82 for a rate of work which is considered hard labor. For this degree of work, 50 per cent were fairly comfortable for temperatures ranging from 46'to 64 deg ET, while the greatest percentage found maximum comfort at 53 deg ET, In hot industries, SO deg ET is considered the upper limit compatible with efficiency, and, whenever possible, this should be reduced to 70 deg ET or less. ' '> . APPLICATION OF COMFORT CHART The average winter comfort line (66 deg ET) applies to average -----1 ------ tha hrnarl brpntrranhic belt across "Humidification for Residences, by A. P. Kratj, (University of Illinois Engineering Experiment Station Bulletin No. 230. July 28, 1931). '. . ''Ventilation, Report of the New York State Commission on Ventilation, 1923. "A.S.H.V.E. research paper entitled Heat and Moisture Losses from Men at Work and Application to Air Conditioning Problems, by F. C. Houghten, W'. W. Teague, W. E. Miller and W. P. Yant (A.S.H.V.E. Transactions, Vol. 37, 1931). 71 of andAmerican Society Heating Ventilating Engineers Guide, 1936 the United States in which central heating of the convection type is generally used during four to eight months of the year. It does not apply to rooms heated by radiant energy, or to rooms with excessive glass area . or rooms with poorly insulated or cold walls, and it has not been advocated officially for use in foreign countries where the climate, heating methods and general living conditions are materially different from those in the United States, although several foreign workers have attempted to show that it cannot be so applied. Even in the warm south and southwestern climates, and in the very cold north-central climate of the United States, the comfort chart would probably have to be modified according to climate, living and working conditions, and the degree of acquired adaptation. In densely occupied spaces, such as classrooms, theaters and audi toriums, somewhat lower temperatures are necessary than those indicated by the comfort line on account of counter-radiation between the bodies of occupants22, in close proximity. In rooms in which the average wall surface temperature is considerably below the air temperature, higher air temperatures are necessary. The reverse holds true in radiant or panel heating methods. (See Chapter 38.) The sensation of comfort, in so far as the physical environment is con cerned, is not absolute but varies considerably among certain individuals. Therefore, in applying the air conditions indicated by the comfort line, it should not be expected that all the occupants of a room will feel per fectly comfortable. When the winter comfort line is applied in accordance with the foregoing recommendations, the majority of the occupants will be perfectly comfortable, but there will always be a few who would feel a bit too cool and a few a bit too warm. These individual differences among the minority should be counteracted by suitable clothing. Air conditions lying outside the average comfort zone but within the extreme comfort zone may be comfortable to certain persons. In other words, it is possible for half of the occupants of a room to be comfortable in air conditions outside the average comfort zone, but in the majority of. cases, if not in all, these conditions will be well within the extreme comfort zone as determined experimentally. ' Strictly speaking, the only authoritative comfort zone on which accur ate data are available, is tliat for 15 to 25 fpm air movement or- tur- bulance (often referred to as still air). In the past, the winter comfort zone has often been superimposed on effective temperature charts for various air velocities, on the Assumption that air conditions of equal warmth are approximately equally comfortable. This may hold in hot industries where the workers are adapted to high temperatures and strong air currents, but it does not apply to sedentary conditions. To ascertain approximately whether a given industrial condition is reasonably com fortable, it would be necessary first to compute the effective temperature from Figs. 1, 2 or 3, and then to refer this effective temperature to the comfort chart (Fig. 5), or to refer directly to a chart or table for the proper air velocity. .. The summer comfort line (71 deg ET) is applicable to the same geo graphic area as the winter comfort line. It is further restricted to cases in which the human body has reached thermal equilibrium with its environ ment. As a general rule this takes place after 1)^ to 3 hours' exposure. 72 -v 3--Ventilation and Air Conditioning Standards ,, nproon from outdoors enters a room cooled to 71 deg ET on a hot j ^ or over) an intense chill is likely to be experienced which is dayi ^ ant However, after remaining in the room for about 2 hours, ^fundamental optimum condition will prove satisfactory to the average tms iu The summer comfort zone, as well as the comfort line, makes Pfnner allowance for these adaptive changes in the body, and thus applies f homes offices, schools and other similar places where. persons of sedentary'occupations spend from 3 to 8 or more hours daily. In artificially cooled theaters, department stores, restaurants, and other nublic buildings where the period of occupancy is short, the contrast between outdoor and indoor air conditions becomes the deciding factor in reeard to the temperature and humidity to be maintained. The object of cooling such places in the summer is not to reduce the temperature to the Table 2. Desirable Indoor Air Conditions in Summer Corresponding ' to'Outdoor Temperatures Applicable to Exposures Less Than S Hours Outdoor Temperature (Deo Fahb) Drt-Bulb 95 90 85 80 7570 Indoor Air Conditions with Dew Point _ . Constant at 57 P Dbt-Bulb Wet-Bulb Effective Temp ' 80.0 78.0 76.5 75.0 73.5 72.0 65.0 ' 73 ; 64.5 72 64.0 . 71 63.5 ' 70 63.0 69 62.5 68 optimum degree, but to maintain therein a temperature which is tem porarily comfortable to the patrons who thus avoid sensations of chill and intense heat on entering and leaving the building. The relative humidity should be low enough (about 50 per cent or less) to give a sense of comfort without chill and to induce a rate of evaporation which will keep clothing and skin dry. For exposures less than 3 hours, desirable indoor conditions in summer corresponding to various outdoor temperatures are given in Table 2. ` It should be kept in mind that southern people, with their more sluggish heat production and lack of adaptability, will demand a comfort zone several degrees higher than those given here for the more active people of northern climates. Instead of the summer comfort line standing at 71 deg as here given, it was found to be much higher for foreigners in Shanghai where climatic conditions are similar to those of our gulf states. This difference in basic metabolic level of people forms a very real problem for air conditioning engineers, which they must recognize in their efforts to give proper conditions of comfort, Cooling of theaters, restaurants, and other public buildings in southern climates cannot be based on northern standards without considerable modification. 73 of andAmerican Society Heating Ventilating Engineers Guide, 1936 A.S.H.V.E. VENTILATION STANDARDS33 It is the intent of the Committee in presenting this report to confine itself to a statement of those requirements which, based on present day knowledge, will provide adequate ventilation for spaces intended for human occupancy. The following standards shall apply to all spaces occupied by human beings in all buildings for which ventilation regulations are to be established. SECTION I--AIR TEMPERATURE AND HUMIDITY The temperature and humidity of the air in such occupied spaces, and in which the only source of contamination is the occupant, shall be maintained at all times during occu pancy at an Effective Temperature, as hereinafter stated- The relative humidity shall be not less than 30 per cent, nor more than 60 per cent in any case. The Effective Temperature shall range between 64 deg and 69 deg when heating or humidification is required, and between 69 deg and 73 deg when cooling or dehumidification is required. These Effective Temperatures shall be maintained at a level of 36 in. above the floor. (See Appendix, Tables A and B). SECTION II--AIR QUALITY The air in such occupied spaces shall at all. times be free from toxic, unhealthful or disagreeable gases and fumes and shall be relatively free from odors and dust. In every space coming within the provisions of these requirements and in which the quality of the air is below the standards prescribed by good medical and engineering practices, due to toxic. substances, bacteria, dust, excessive temperature, excessive humidity, objectionable odors, or other similar causes, means for ventilating shall be provided so that the quality of the air shall be raised to these standards. SECTION III--AIR MOTION The air in such occupied spaces shall at all times be in constant motion sufficient to maintain a reasonable uniformity of temperature and humidity, but not such as to cause objectionable drafts in any occupied portion of such spaces. The air motion in such occupied spaces, and in which the only source of contamination is the occupant, shall have a velocity of not more than 50 ft per minute, measured at a height of 36 in. above the floor. _. SECTION IV--AIR DISTRIBUTION The air in all rooms and enclosed spaces shall, under the provisions of these require ments, be distributed with reasonable uniformity, and the variation in the carbon dioxide content of the air shall be taken as a measure of such distribution. . The air in a space ventilated in accordance with these requirements, and in which the only source of contamination is the occupant, shall be distributed and circulated so that the variation in the concentration of carbon dioxide, when measured at a height of 36 in. above the floor, shall not exceed one part in 10,000. SECTION V--AIR QUANTITY The quantity of air used to ventilate the given space during occupancy shall always be sufficient to maintain the standards,of air temperature, air quality, air motion and air distribution as herein required. Not less than 10 cu ft per minute per occupant of\the total air circulated to meet these requirements shall be taken from an outdoor source. APPENDIX Definitions For the purposes of these standards the terms used shall be defined as follows:-- . Ventilation: The process of supplying or removing air by natural or mechanical means, to or from any space. Such air may or may not have been conditioned. (See Air Conditioning). 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, distribution, dust, bacteria, odors, toxic gases, and ionization, most of which affect in greater or lesser degree human health or comfort. - "Report of A.S.H.V.E. Committee on Ventilation Standards consisting of W. H. Driscoll, Chairman, 1. J. Aeberly, F. Paul Anderson. L. A. Harding. D. D. Kimball. J. R- McColl, C. L. Riley. W. A. Rowe. Perry West and A. C. Willard, presented at the Semi-Annual Meeting of the Society, Milwaukee, Wis., June. 1932. and adopted by the Society in August. 1932. , - 74 ' T^apter 3---Ventilation and Air Conditioning Standards . _,,,,ture. The temperature of the air which is indicated by any type of thermometer Dry-Bulb I ^ waler TOp0I content or relative humidity of the air. which is not an finely divided state, the particles of which are large and heavy enough to fall Dust: Sohd matorai in ^ in still air. For instance, particles of fine sand or grit, such as are with increasing vcnxaiy.^u av{ra`e dimeter 0f which is approximately 0.01 centimeter, may be called dust, blown on a win ' rurB. An arbitrary index of the degree of warmth or cold felt by the human body Effective l emperai _ `humidity, and movement of the air. Effective temperature is a comptMfte in response to tempera.^. ,, of temperature, humidity, and air morion into a single value. The index which comDinra t e temperature scale has been fixed by the temperature of saturated air which numerical v?J^tical ^njation of warmth. induces an vapor (either saturated or superheated steam) occupying any space, which may H v^ifrentain oServapon and gases at the same time, or may not A ratio, although usually expressed in per cent, used to indicate the degree of Relative Humjuity ^ space resulting from the water vapor present in that space. The presence saturation exisripg many ^a at the time has nothing to do with the relative humidity of l "nsa*01`wSi^depends merely on the temperature and partial pressure of the vapor. ' i,, which the Only Source of Contamination la the Occupant: Spaces in which the Spaces in w^ n results entirely from the respiratory processes of the occupant, including heat, atmospheric contam n ,, . h5 bot|y No manufacturing or industrial processes or other sources of atmmpheric comamination, induding heat and moisture, than people are considered under this title. _ ,. TablbA. pvpective Temperatures Ranging prom 64 Deg to 69 Deg for Various Dry-Bulb TbmRelative Humidities for Still Air for Persons Normally Clothbo and Slightly Active. (For use when heating or humidification is required) Temperatures (Dec Fahr) 30 Relative Humidities (Per Cent) .. 35 40 45 50 55 Effective Temperatures (Degrees) 60 67 68 69 70 64.1 64.8 65.5 64.4 65.1 65.8 64.0 64.8 65.4 66.2 64.2 65.1 65.8 66.6 64.5 65.4 66.2 67.0 64.0 64.8 65.7 66.5 67.3 64.3 65.1 66.0 69.8 67.7 66.2 66.5 66.9 67.3 67.7 68.1 68.5 67.0 67.3 67.7 68.1 68.5 68.9 74 67.7 68.0 68.4 68.8 75 68.4 68.7 76 69.0 See Fig. 5. Table B. Effective Temperatures Ranging from 69 Deg to 73 Deg for Various Dry-Bulb Tem peratures and Relative Humidities for Still Air for Persons Normally Clothed and Slightly AcrrvEa-b (For use when cooling or dehumldlfication ls required) Dry-Bulb Temperatures (Deg Fahr) 30 Relative Humidities (Per Cent) 35 40 . 45 50 55 Effective Temperatures (Degrees) 60 73 74 ' 75 76 77 78 79 80 81 69.0 69.7 70.4 71.1 71.8 72.5 69.4 70.2 70.9 71.8 72.4 69.1 69.9 70.7 71.4 72.2 72.9 69.5 70.5 71.2 71.9 72.6 69.3 70.0 70.8 71.6 72.4 69.7 71.5 71.3 72.1 73.0 69.3 70.1 71.0. ' 713 . 72.6 See Fig. 5. ' bThls table applies primarily to cases in which the human body has reached equilibrium with the sur rounding air. A higher plane of summer effective temperatures is required in places of public assembly where the period of occupancy is short, than is required for offices and industrial plants where the period of occupancy is of longer duration. When the period of occupancy is two hours or less, the dry-bulb tempera ture shall be 72 F plus one-third of the difference between the outside dry-bulb temperature and 70 F, and the relative humidity shall not exceed 60 per cent. (See also Table 2.) 75 of and 1936American Society Heating Ventilating Engineers Guide, FACTORS INFLUENCING APPLICATIONS The conditions and limitations outlined under the heading Application of Comfort Chart should be noted in applying the temperatures and - relative humidities specified in Tables A and B of the preceding A.S.H.V.E. Ventilation Standards. Air.Quality In occupied spaces in which the vitiation is entirely of human origin, the chemical composition of the air, the dust, and bacteria content may be dismissed from consideration so that the problem consists in maintaining a suitable temperature with a moderate humidity, and in keeping the atmosphere free from objectionable odors. Such unpleasant odors, human or otherwise, can be easily detected by persons entering the room from clean, odorless air. A further discussion of air quality will be found in Chapters 15 and 16. Air Motion As a result of studies by Baetjer34 and work carried on by the A.S.H.V.E. Research Laboratory, it is now recognized that the importance of air motion in air conditioning ranks only second to temperature. Air in an occupied space having all the other essential qualities but lacking in air motion feels stagnant, stuffy, and depressing, because the vitiated air nexf to the body is not replaced by the surrounding air possessing the satisfactory qualities. Hence, air motion is absolutely essential that an occupant may. realize the other desired qualities of the atmosphere. Possible limits in variation in-air motion may range from 5 fpm to 50 fpm, as measured by the Kata thermometer. (See Chapter 43.) However, satisfactory results are more likely to be insured by air velocities ranging from 15 to 30 fpm. The limit, of 5 fpm may be taken as the minimum during the heating season, and 50 fpm as the maximum for the cooling season. Air Distribution Variation in concentration of carbon dioxide in different parts of an occupied room has been used as a measure of satisfactory distribution of the outside or conditioned air supply. For satisfactory air distribution, ..the carbon dioxide concentration at the 36-in. level should not vary by more than one part in 10,000 parts of air. Recent work2 by the A.S.H.V.E. Research Laboratory demonstrates that variations in dry-bulb tempera ture, wet-bulb temperature, or moisture content of the air are equally good indices of air distribution; This work also indicates that the presence of satisfactory air motion within the room (15 to 30 fpm'as measured by the Kata thermometer) insures satisfactory, distribution. Because of the laborious and exacting technique involved in making carbon dioxide determinations, it is recommended that satisfactory distribution can be amply insured by the presence of such air velocities in all parts of the room together with dry-bulb temperature variations of not to exceed 3 deg at, the 36-in. level;. ... "Threshold Air Currents in Ventilation (American Journal of Hygiene, Vol. IV. No. 6, p. 6S0. 1924)." 76 ^Ciiapter^--Ventilatin and Air Conditioning Standards Air Quantity Thp Quantity of air to be circulated through an occupied space, whether , 1 net^ral or mechanical means, or whether the air is conditioned or not, ' T' all cases be sufficient to maintain the required standards of air mUS * ature quality, motion and distribution. The factors which deterte`n!Tair quantity include the type and nature of the building, locality, "fmate height of rooms, floor area, window area, extent of occupancy, and last but not least, the method of distribution. The quantity of air supplied to a room by an air conditioning or venti lating system serves two purposes: First, the supply of sufficient outside ir for the needs of the occupants; and second, the setting up of circulation ar ajr motion within the room. Until recently it was considered that 30 cfm were necessary in any occupied space, particularly in a classroom. It has since been demonstrated that 10 cfm of outside air per person is frequently sufficient to remove body heat, insure against body odors, and provide the chemical needs of respiration. However, it is found that a greater volume should be circulated in the average room in order to provide the required air motion, It is now customary to supply the minimum amount of outside or conditioned air required for removing heat and odors, and to recirculate the additional volume. In offices and small rooms where the occupants smoke, from 6 to 7 cfm of outside air per occupant will be necessary to eliminate the nuisance effects of the smoke; this quantity of air, however, may be a part of that necessary for other ventilation requirements. Restaurants which permit smoking, because of the exposed food and the necessity that restaurant air seem very clean, need from 10 to 12 cfm of outside air per occupant to care for the smoke condition. This air, likewise, need not be in addition to that required for other ventilation purposes. . Temperature Rise The total quantity of air introduced is governed largely by the needs for controlling temperature and humidity when either heating or cooling is required. As a rule,, the introduction and distribution of warm air into an occupied space does not present as many difficulties as does the intro duction of cold air. The former is determined from the amount of heat to be given up to the space, and the latter is determined from the amount of heat to be removed from the space, using a temperature rise that will produce uniform distribution without the production of disagreeable drafts. Fig. 6 shows the changes in carbon dioxide concentration and moisture content resulting from occupation, in the atmosphere of a room supplied with various volumes of outside air. Data are given for an adult, 5 ft 8 in. in height weighing 150 pounds and-having a body surface area of 19.5 sq ft, and for a child, 12 years of age, 4 ft 7 in. in height, weighing 76.6 pounds and having a body surface area of 12.6 sq ft. It is a recognized fact that the dissipation of heat and moisture to the atmosphere, the addition of carbon dioxide, and all metabolic changes take place in pro portion to the surface area of the individual. Hence, data for persons of other sizes may be . obtained by interpolating among the curves given.. The rate of sensible heat production is given in Fig. 9. Fig. 6 also gives 77 ofAmerican Society Heating and Ventilating Engineers Guide, 1936 the temperature of the incoming air necessary to maintain a room tem perature of either 70 or 80 F as indicated, assuming that there is no. heat gain or loss to the room by transmission through the walls, solar radiation or other sources. . "Chapter 3___Ventilation and Air Conditioning Standards bution produce drafts with but a few degrees temperature rise, while other systems operate successfully with a temperature rise as high as 35 deg. The total air quantity introduced in any particular case is inversely proportional to the temperature rise, and depends largely upon the judgment and ingenuity of the engineer in designing the most suitable system for the particular conditions. Outside Air. In order to provide uniform temperature conditions, it is necessary to maintain a pressure of about 0.1 in. of water in the room or space to be ventilated or conditioned. This usually requires the iiitro- nf outside air which deoends on the particular Fig. 6. Relation Among Rate of Air Change per Occupant, Carbon Dioxide Concentration and Moisture Content of Enclosure, and Dry-Bulb . Temperature of Incoming Air Two of the most important factors on which the temperature rise . depends are (1) the method of distribution and (2) the most economical 1 temperature rise for the conditions involved. Some systems of distri- > 78 5 H NATURAL and mechanical ventilation Under favorable conditions natural ventilation methods properly combined with means for heating may be sufficient to provide for the foregoing standards. As a rule, in instances in which the only source of contamination is the occupant, the requirements may be fulfilled when the following conditions prevail: 1. At least 50 sq ft of floor area for each occupant, 2. At least 500 cu ft of air space per occupant. 3. Effective openings in windows and skylights equal, to at least 5 per cent of the floor area. Whenever natural means are not sufficient to maintain the standards, resort must be made to whatever modifications or mechanical apparatus are necessary to secure such standards. In large offices, large school.rooms, and in public and industrial buildr ings, natural ventilation is uncertain and makes heating difficult. The chief disadvantage of natural methods is the lack of control; they depend largely on weather and upon the velocity and direction of the wind. Rooms bn the windward side of a building may be difficult to heat and ventilate on account of drafts, while rooms on the leeward side may not receive an adequate amount of air from out of doors. The partial vacuum produced on the leeward side under the action of the wind may even reverse the flow of air so that the leeward half of the building has to take the drift of the air from the rooms of the windward half. Under such conditions no outdoor air would enter through a leeward window opening, but room air would pass out. In warm weather natural methods of. ventilation afford little or no control of indoor temperature and humidity. Outdoor smoke, dust and noise constitute other limitations of natural methods. RECIRCULATION AND OZONE The saving in operating costs due to recirculation of the air, while very considerable, must not be obtained at the expense of air quality. The percentage of recirculated air may be varied to suit the seasonal changes so as to conserve heat in winter and refrigeration in summer, but at no time during occupancy should there be taken from out of doors less than . American Society of Heating and Ventilating Engineers Guide, 1936 10 cfm for each occupant. As a general rule, recirculation impairs the quality of the air by excessive humidity (if not conditioned), excessive odors, or both, and it tends to deprive the air of its ionic content, but the influence of this factor on comfort and health is at present a matter of speculation. . , Ozone has been used as an adjunct to ventilation as a deodorant particularly where a portion of the air is recirculated in order to effect a saving in both heating and refrigeration. At proper concentrations ozone exerts practically no effect on pathogenic air borne organisms, but will eliminate most of the undesirable odors usually present in recirculated air. It is very important to use only equiptment which provides for positive control of ozone output, as higher concentrations produce a pungent and Fig. 7. Influence of Room Occupancy on Ionic Content*5 (Cubical Contents of Room, 10,000 Cu Ft; Number of Occupants, 34) unpleasant odor, with considerable discomfort to human beings so exposed. Toilets, kitchens, and similar .rooms, in buildings using recirculation, should be separately mechanically ventilated by exhausting the air from them in order to prevent objectionable odors from diffusing into other parts of the building. '. " . ULTRA-VIOLET RADIATION AND IONIZATION In spite of the rapid advances made in the field of air conditioning during the past few years, the secret of reproducing, in indoor spaces, atmospheres of as stimulating qualities as those existing outdoors in the country, under ideal weather conditions, has not as yet been found. In fact, extensive studies have failed to elucidate the cause of the stimulating quality of outdoor country, air, qualities which are: lost when such air is brought .indoors and particularly when it is handled by mechanical 80 Chapter 3--Ventilation and Air Conditioning Standards Table 3 Relation Between Metabolic Rate and Activity55 Activity Metabolic Rath Btu per Hour roa Average Man (19.5 Sq Ft Sur face Area) Authority Seated at icbt. Standing at rest--.... Very severe exercise-- Maximum exertion...... Painter (of furniture).. Man sawing wood------ 384 Research Laboratory, American Society of Heating and Ventilating Engineers. 431 Research Laboratory, American Society of Heating and Ventilating Engineers. 761 Average values from Douglas, Haldane, Henderson and Schneider; and Henderson and Haggard. 1049 1388 Douglas,. Haldane, Henderson and Schneider Average values from Douglas, Haldane, Henderson and Schneider; and Henderson and Haggard. 2530 Douglas, Haldane, Henderson and Schneider 2285 ockc Henderson and Haggard Benedict and Carpenter 3333 to 4762+ Henderson and Haggard 482 Becker and Hamalainen 626 . Becker and Hamalainen 661 . Becker and Hamalainen 762 to 963 Becker and Hamalainen 862 Becker and Hamalainen 876 Becker and Hamalainen . 1488 . Becker and Hamalainen 1797 Becker and Hamalainen means. It is true that many suggestions have been advanced to account for the stimulating quality of outdoor air, such as ultra-violet light and ionization. At the present time neither of these suggestions has received any degree of scientific confirmation. . It is generally recognized that total outdoor solar radiation has marked curative value in certain diseases and is also a powerful germicidal agent. A critical review of the literature, however, does not substantiate the theory that ultra-violet radiation is of importance in air conditioning, since the use of ultra-violet sources fails to produce indoors, the pre viously mentioned stimulating qualities found in outdoor air. Experiments36 show that in occupied rooms there is a marked decrease in both positive and negative small ions. As shown in Fig. 7, soon after the occupants assembled the ionic content fell abruptly to a very low level which was maintained until the occupants left the room. Both positive , and negative ions began to rise again as soon as the occupants departed.;; The effects of the decrease in the ionic content of indoor air on comfort and health have not yet been subjected to sufficient scientific investiga tion. It would appear, however, from the evidence at hand, that comfort is not associated with a high ion content--but this must be considered, at least for the time being, as still a subject for further study. A.S.H.V.E. research paper entitled Changes in Ionic Content in Occupied Rooms, Ventilated by Natural and Mechanical Methods, by C; P. Yaglou, L, C. Beniamin and S.P. Choate (A.S.H.V.E. Trans actions, Vol.,37,1931). Physiologic Changes During Exposure to Ionized Air, by C. P. Yaglbu, A,- D. Brandt and L. C. Benjamin (A.S.H.V.E. Transactions, Vol. 39, 1933), Diurnal and Seasonal Variations in the Small Ion Content of Outdoor and' Indoor Air, by C. P. Vaglou and L. C. Benjamin (A.S.H.V.E. Transactions, Vol. 40, 1934). The Nature of Ions in Air and their Possible Physiological Effects, L.B. . Loeb (A.S.H.V.E. Transactions^ Vol. 40, 1934). ' :. ' 81 1 of andAmerican Society Heating Ventilating Engineers Guide, 1936 HEAT AND MOISTURE LOSSES In order to solve air conditioning problems involving the human body it is necessary to know the rate at which sensible and latent heat are given up by the body under various conditions of temperature and activity Research at the A.S.H.V.E, Laboratory32' 36 has resulted in the data given in Figs. 9,10,andll. Table 3 gives the metabolic rates for various degrees of activity. The experimental data from which the curves were drawn show that -------- ------- Chapter 3___ Ventilation and Air Conditioning Standards ^itions of humidity and air motion, they are plotted as such in the conai ^.s .g accomplished by approximations which are sufficiently C^Ste for application to practical problems. Comparison of Figs. Qanrf 10 shows how the cooling load may vary between sensible and latent heat elimination for different atmospheric conditions and activities of Fig. 8. Relation Between Total Heat Loss from the Human Body and Effective Temperature for Still Air aCurve A--Men working 66,160 ft-lb per hour. Curve B-- Men working 33,075 ft-lb per hour. Curve C--Men working 16,538 ft-lb per hour. Curve D--Men seated at rest. Curves A and C drawn from data at an effective temperature of 70 deg only and extrapolating the relation between curves B and D, which were drawn from data at many temperatures. total heat loss does not vary appreciably within the comfort zone (see Fig. 8). Above or below this range the variation is approximately a function of effective temperature. Sensible and latent heat losses (Figs. 9 and 11) on the other hand, vary greatly within the comfort zone, the variation following closely the dry-bulb temperature. Although total heat loss and sensible and latent heat losses are not exact functions of effective and dry-bulb temperature, respectively, for all "Thermal Exchanges Between the Bodies of Men Working and the Atmospheric Environment, by F. C. Houghten, W. W. Teague, W. E. Miller, and W. P. Yant (American Journal of Hygiene, Vol. XIU, No. 2, March, 1931, pp. 415-431). 82 . Fig. 9. Relation Between Sensible Heat Loss from the.Human Body and Dry-Bulb Temperature for Still Air3 *Curve A--Men working 66,150 ft-lb per hour. Curve B-- Men working 33.075 ft-lb per hour. Curve C--Men' working 16,538 ft-lb per hour. Curve D--Men seated at rest. Curves A and C drawn from data at a dry-bulb temperature of 81.3 F only and extrapolating the relation between curves B and D which were drawn from data at many temperatures. avoided for obvious reasons. Tables 4 and 5 give the approximate effec tive temperatures at which perspiration is noticeable in different degrees for 95 per cent and 20 per cent relative humidity. In theaters, auditoriums, department stores and other crowded en closures, the amount of heat and moisture given off by the people is so large that normal changes in outside temperature and humidity have relatively little effect on indoor air conditions. The principal object of air conditioning in such places is to remove excessive heat and moisture by supplying a sufficient quantity of properly conditioned air. The indoor air conditions, however, must be varied according to the, outside tem perature, as has been pointed out. 83 American Society of Heating and Ventilating Engineers Guide, 1936 Fig. 10. Latent Heat and Moisture Loss from the Human Body by Evaporation in Relation to Dry-Bulb Temperature for Still Air Conditions3 ' Curve A--Men working 66,150 ft-lb per hour. Curve B--Men working 33,075 ft-lb per hour. Curve C--Men working 16.538 ft-lb per hour. Curve D--Men seated at rest. Curves A and C drawn from data at a dry-bulb temperature of 81.3 F only and extrapolating the relation between Curves B and D which were drawn from data at many temperatures. ' ' ,r Fig. 11. Heat Loss from the Human Body by Evaporation, Radiation and Con- ; vection in Relation to Dry-Bulb Temperature for Still Air Conditions3 Curve A--Meu working 66,150 ft-lb per hour. Curve B--Men working 33,075 ft-lb per hour. Curve - C--Men working 16.538 ft-lb per hour. Curve D--Men seated at rest. Curves A and C drawn from data .< at a dry-bulb temperature of 81.3 F only and extrapolating the relation between Curves B and D which were i drawn from data at many temperatures. h 84 '' . ; "Chapter 3__ -Ventilation and Air Conditioning Standards ` . , h heat and moisture from the human body constitute the major nf the cooling load, in most cases where air conditioning is pro-. P^for comfort and health other factors'must also be considered. These video io lights, machinery, and processes, as well as the trans mission ^and infiltration of heat through the building structure The imputations for these factors may be made in accordance with data given in Chapters 5 and 7. ~Table 4a. rl^ownnuiThTwON OwF Sen__s_i_b_le Perspiration for Persons Seated at Rest Degree of Perspiration* Atmospheric Condition 95 Per Cent Relative Humidity 20 Per Cent Relative Humidity Forehead clammy...-....... Body clammy_---.... - Body damp.......... ........... Beads on forehead-------Body wetPerspiration on forehead runs and drips.----- Perspiration runs down body------------------------- E. T. 73.0 73.0 79.0 80.0 84.5 88.0 88.5 D. B. 73.6 73.6 79.7 80.8 85.4 89.0 89.5 W. B. 72.4 72.4 78.4 79.4 84.0 87.6 88.1 E. T. D. B W. B. 75.0 75.0 81.0 87.0 86.5 94.0 90.0 87.0 87.0 97.5 109.4 108.5 125.2 116.0 60.7 60.7 67.5 75.2 74.6 85.4 79.5 Forty per cent of subjects registered degree of perspiration equal to or greater than indicated. Table 5. Condition of Sensible Perspiration for Persons at Work ' Under Various Atmospheric Conditions Atmospheric Condition ' Degree or Perspiration* 95 Per Cent Relative ; 20 Per Cent Relative Humidity Humidity* E. T. D. B. W. B. E. T. D.B. W.B. Forehead clammy--J........................... ---.......... Body clammy Body damp..........- .............................................. Beads on forehead__ ________ -....................... Body wet----------------------------------------------------Perspiration on forehead runs and drips.------- Perspiration runs down body- -- ----------- 59.0 50.0 60.0 68.0 69.0 78.5 79.0 59.4 50.2 60.3 68.5 69.6 79.3 79.8 58.3 49.3 59.3 67.5 68.5 78.0 78.5 69.5 57.0 62.5 76.0 71.0 82.0 81.0 80.5 61.6 69.6 91.0 82.8 100.5 99.8 56.5 44.2 49.5 63.4 53.0 70.2 69.0 Forty per cent of subjects registered degree of"perspiration equal to or greater than indicated. In many cases, allowance must also be made for sun effect and for heat capacity of the building structure in accordance with studies by the A.S.H.V.E. Research Laboratory87. Another item,to be considered is the radiant heat received by the body from high temperature wall and ceiling surfaces. , ' '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.E. Transactions, Vol. 38, 1932). ` of andAmerican Society Heating Ventilating Engineers Guide, 1936 * PROBLEMS IN PRACTICE 1 Determine the amount of sensible and latent heat given off by each person on a dance floor if the dry-bulb temperature is 75 F. First select from Table 3 an occupation which would seem approximately as strenuous as dancing. Let us assume that the average dancer will have the same metabolic rate as a person walking 3 miles per hour. Then the total heat emission will be 1049 Btu per hour per person. If we assume that conditions in the dance hall are within the comfort zone, then we can locate our point with reference to the curves in Fig. 8. We find that 1049 Btu falls between curves A and B, and slightly closer to B. Knowing this, the amounts of sensible and latent heat may be determined from Figs. 9 and 10, or the relative amounts may be determined from Fig. 11. . Using Fig. 11, we find that for a 75 F dry-bulb temperature, approximately 61 per cent of the heat will be by evaporation and 39 per cent will be sensible heat. Latent heat = 1049 X 0.61 = 640 Btu per hour. Sensible heat = 1049 X 0.39 = 409 Btu per hour. ' 2 What is the purpose and method of conditioning the air of occupied rooms? Chiefly comfort, and the method is to control the temperature, humidity, and air distri bution, and to prevent the accumulation of excessive body odors in the air. Other factors have yet to be studied. . 3 What are the most comfortable air conditions? Comfort standards are not absolute, but they are greatly affected by the physical con dition of the individual, and the climate, season, age, sex, clothing, and physical activity. For the northeastern climate of the United States, the conditions which meet the require ments of the majority of people consist of temperatures between 68 and 72 F in winter and between 70 and 85 F in summer, the latter depending largely upon the prevailing outdoor temperature. The most desirable relative humidity range seems to be between 30 and 60 per cent. 4 Are the optimum conditions for comfort identical with those for health? There are no absolute criteria of the prolonged effects of various air conditions on health. For the present it can be only inferred that bodily discomfort may be an indication of conditions that may produce poor health. .. 5 Given dry-bulb and wet-bulb temperatures of 75 and 68 F, respectively, first, what is the effective temperature? Second, is this condition warmer or cooler than 80 F dry-bulb and 60 F wet-bulb? j The first condition is given by the intersection of the 75 F dry-bulb line and the 68 F wet- bulb line (Fig. 5). The effective temperature of 72.1 deg is given by the numerical value of the effective temperature line passing through this point and indicated by the scale along the saturation curve.; The second condition is given by the intersection of 80 F dry-bulb and 60 F wet-bulb and is 71\8 deg ET. It is therefore 0.3 deg ET cooler than the first condition. - . ; 6 Given 76 F dry-bulb and 61 F wet-bulb, how many degrees difference are there between this condition and the winter comfort line or 66 deg ET? The effective temperature for this condition is given by the intersection of the 76-F dry- bulb and 61-F wet-bulb lines and is 70 deg ET, which is 4 deg ET warmer than the comfort line. '' -. 7 Assume that the design of an air conditioning system for a theater is to be based on an outdoor dry-bulb temperature of 95 F and a wet-bulb temperature of 78 F with an indoor relative humidity of 50 per cent. According to Table 2, the dry-bulb temperature in the auditorium should be 80 F. Estimate the sensible and latent heat given up per person. ' The sensible heat given up per person per hour under this condition may be obtained ; from Fig. 9. With an abscissa value of 80 F, Curve D for men seated at rest gives a value ; 86 i 3___Ventilation and Air Conditioning Standards on the ordinate scale of 220 Btu per person per hour as the sensible heat loss. The llaatteent heat given up by a person seated atrestperhour may be obtained from Fig. 10. With an abscissa value of 80 F, Curve D indicates a latent heat loss of 175 Btu per hour (left hand scale) or a moisture loss of 1190 grams per hour (right hand scale). g ^ How much sensible heat, how much latent heat and how much water vapor will be added per hour to the atmosphere of an auditorium by an audience of 1000 adults, when the dry- and wet-bulb temperatures are 75 F and 63.5 F, respectively? ' From Curve D, Fig, 9, find the sensible heat loss per person for a dry-bulb temperature of 75 F and still air to be 265 Btu per hour. From Fig. 10 find the latent heat loss per person for a dry-bulb temperature of 75 K to be 134 Btu per hour and the moisture added to be 905 grains per hour. Sensible heat = 1000 X 265 = 265,000 Btu. Latent heat = 1000 X 134 = 134,000 Btu. Water vapor added per hour to the air in the auditorium = 1000 X 905 = 905,000 grains or 129 lb. The sensible and latent heat added .to the air may also be found as follows: The effective temperature for dry- and wet-bulb temperatures of 75 F and 63.5 F, respectively is 70.3 deg. From Curve D, Fig. 8, find 403 Btu as the total heat added to the air by a person for an effective temperature of 70.3 deg. From Fig. 11 find the percentage of sensible and latent heat at a dry-bulb temperature of 75 F to be 66.5 per cent and 33.5 per cent. The sensible heat added to the air in the auditorium is 1000 X 0.665 X 403 = 267,995 Btu per hour. The latent heat added is 1000 X 0.335 X 403 = 135,005 Btu per hour. * 9 If the dry- and wet-bulb temperatures of the auditorium were 85 F and 63 F, respectively, how much heat and moisture would be dissipated to the atmosphere? From Figs. 9 and 10, respectively, the sensible and latent heat losses per person for a drybulb temperature of 85 F are found to be 164 and 225 Btu per hour. The water vapor added to the atmosphere is 1520 grains per hour. The audience will then add 164 000 Btu sensible heat, 225,000 Btu latent heat and 1,520,000 grains or 217 lb of water vapor to the air in the auditorium per hour. . 10 Neglecting the gain or loss of heat to an auditorium by transmission or infiltration through the walls, windows and doors, how many cubic feet of outside air, with dry- and wet-bulb temperatures of 65 F and 59 F, respectively, (63-1 deg ET) must be supplied per hour to an auditorium containing 1000 people in order that the inside shall not exceed 75 F (dry-bulb) and 65 F (wet- bulb), respectively? Figs. 9 and 10 give 265 Btu sensible heat and 905 grains of moisture as the additions per person with a dry-bulb temperature of 75 F in the auditorium. Therefore, 265,000 Btu of sensible hesat and 905,000 grains of moisture will be added to the air in the auditorium per hour. . Taking 0.24 as the specific heat of air, 2.4 Btu per pound of air will be required to raise the dry-bulb temperature from 65 to 75 F and = 110,400 lb of air or 110,400 X 13.4 = 1,479,000 cfh of air will be required. This is equivalent to = 24.7 cfm , 1UUU X OU per person. . The moisture content of the inside air as taken from a psychrometric chart is 76 grains per pound of dry air and that of the outside condition is 65 grains. The increase in moisture content will therefore be 11 grains per pound of dry air. Hence ---- = 82,300 lb of air at the specified condition will be required. This is equivalent to 82,300 X 13.4 = 1,103,000 cfh of air or = 18-4 cfm of air per person. 1UUU X oU The higher volume of 24.7 cfm per person will be required to keep the dry-bulb tem perature from rising above the 75 F specified. The wet-bulb temperature will therefore not rise to the maximum of 65 F. 87 of andAmerican Society Heating Ventilating Engineers Guide, 1936 11 The characteristics of air supplied to ventilate a room are: , Carbon dioxide concentration......................... _4 parts per 10,000 Wet-bulb temperature------ ----------------------------.45.2 F Dry-bulb temperature--.....-...................... --55.0 F Moisture content-- .......................... ..............--29.0 grains per pound of dry air . a. What will be the dry-bulb temperature of the air in the room if it is occupied by five adults, if the air change, including both ventilation and infiltration, is 50 cu ft per minute, and assuming that there is no heat gain or loss to the room from any source other than from the occupants? ' b. What will be the carbon dioxide concentration of the air in the room under these conditions? c. What will be the moisture content of the air in the room under these con ditions? d. What will be the wet-bulb temperature and the relative humidity of the air in the room under these conditions? e. What would the temperature of the incoming air have to be to give a room a dry-bulb temperature of 70 F? a. The air change is 10 cu ft per minute per occupant. From the bottom chart of Fig. 6 at the intersection of an incoming air dry-bulb temperature of 55.0 F and a rate of air supply of TO cu ft per minute per occupant, find by interpolation between the 70 F and 80 F adult curves the dry-bulb temperature of the air in the room to be 78.0 F. b. From the top chart of Fig. 6 find the increase in COj concentration to be 10 parts of COt per 10,000 parts of air. Therefore, the air in the occupied room will contain 14 parts of COa per 10,000. c. From the center chart in Fig. 6 find by interpolation between the 70 F and 80 F adult curves the increase in moisture content to be 23 grains per pound of dry air for adults in 78 F air. This gives a resultant moisture content of the air in the room of 52 grains per pound of dry air. d. From the psychrometric chart, Fig. 5, find the resulting wet-bulb temperature and relative humidity for 78 F dry-bulb and 52 grains of moisture to be 61.0 F and 37 per cent,, respectively. e. From the bottom chart, Fig. 6, find the required incoming air temperature to be 42 F dry-bulb. 12 Referring to the A.S.H.V.E. Comfort Chart (Fig. 5), list the conditions (dry-bulb, wet-bulb, effective temperature, and humidity) which will produce comfort at each corner of the average winter comfort zone and of the average summer comfort zone. Average winter comfort zone: Wet-Bulb F . Dbt-Bulb F Relative Humiditt . 58.5 51.5 59.0 67.0 64.5 67.5 79.0 74.0 Average summer comfort zone: Wet-Bulb f; . Drt-Bulb tF 70 per cent 30 per cent 30 per cent . 70 per cent , : Relative . Humiditt " . ... .: 62.0 54.0 63.5 71.5 ., 68.0 72.0 85.0 78.5 88 70 per cent : . 30 per cent ..... . ' . 30 per cent ' 70 per cent Chapter 4 NATURAL VENTILATION Wind Forces, Stack Effect, Openings, Windotes, Doors, Skylights, Roof Ventilators, Stacks, Principles of Control, General Rules, Measurements, Dairy Barn Ventilation, Garage Ventilation VENTILATION by natural forces, supplemented in certain cases with mechanical forces, finds extensive application in industrial plants, public buildings, schools, dwellings, garages, and in farm buildings The natural forces available for the displacement of air in buildings are the wind and the difference m temperature of the air inside and outside the building The arrangement and control of ventilating openings should be such that the two forces act cooperatively and not in opposition Wind Forces In considering the use of natural wind forces for the operation of a ventilating system, account must be taken of (1) average and minimum wind velocities, (2) wind direction, (3) seasonal, daily and hourly varia tions, in wind velocity and direction, and (4) local wind interference by buildings and trees. Table 1, Chapter 8, gives values for the average summer wind velocities and the prevailing wind directions in various localities throughout the United States, while Table 2, Chapter 7, 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 average wind velocities are seldom-below 5 mph, there are many hours in each month during which the wind velocity is from 3 to 5 mph, even in localities where the seasonal average is considerably above 5 mph. There are relatively few places where the hourly wind velocity falls much below 3 mph for more than 10 daylight hours per month. Usually a natural ventilating system should be designed:to operate satisfactorily with a wind velocity of 3 to 6 mph, depending on locality. . The following formula 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: . . where Q = EA V (l) Q = air flow in cubic feet per minute. -.* A = free area of inlet (or outlet) openings in square feet., V = wind velocity in feet per minute, . = miles per hour X 88. E -- effectiveness of. openings. - ,. . - . taken at from SO to 60 per cent if the inlet openings face the wind andfrom-25 to* 35 per cent ii the inlet openings receive the wind at an angle.) - ' - 89 American Society of Heating and Ventilating Engineers Guide, 1936 If outlet openings, where air leaves a building, are smaller than inlet openings, where air enters a building, the air will be less effective than indicated by the constant E. The accuracy of the results obtained by the use of Formula 1 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-edge 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 unusually well placed, the flow will be slightly more than that given by the formula. Inlets should be placed to face directly into the prevailing wind, while outlets should be placed in one of the following four places: 1. On the side of the building directly opposite the direction of the prevailing wind. 2. On the roof in the low pressure area caused by the jump of the wind (see Fig. 1). 3. In a monitor on the side opposite from the wind. 4. In roof ventilators or stacks exposed to the full force of the wind1. Forces due to Stack Effect2 The stack effect produced within a building is due to the difference in weight of the warm column of air within the building and the cooler air outside. The flow due to stack effect is proportional to the square root of the draft head, or approximately: ' where Q = 9A-A V H (I, - t.) (2) . Q = air flow in cubic feet per minute. A = free area of inlets or outlets (assumed equal) in square feet. H = height from inlets to outlets, in feet. 11 = average temperature of indoor air in height H, in degrees Fahrenheit. t% = temperature of outdoor air, in degrees Fahrenheit. 9.4 = constant of proportionality, including a value of 65 per cent for effectiveness of openings. This should be reduced to 50 per cent (constant = 7.2) if conditions are not favorable. ' The height between inlets and outlets should be the maximum which the building construction will allow. In some cases the necessary air-flow will be known from the require ments of the building occupancy, and the area necessary for certain assumed temperature differences may be calculated. Or the areas may be fixed by the building construction, and the maximum air flow for various differences between indoor and outdoor temperatures may be calculated. In any case, the conditions which give the minimum air flow are those which control the design, as the system must have ample capacity even under the most unfavorable conditions which are those of mild or warm weather. . TYPES OF OPENINGS The engineering problems of a natural ventilation system consist of the design, location, and control of ventilating openings to best utilize-the* * ]See Airation of Industrial Buildings, by W. C. Randall (A.S.H.V.E. Transactions. Vol. 34. 1928). *See Neutral Zone in Ventilation, by J. E. Emswiler (A.S.H.V.E. Transactions, Vol. 32,1926), and Predetermining Airation of Industrial Buildings, by W. C, Randall and E. W. Conover (A.S.H.V.E. Trans actions, Vol. 37, 1931). . 90 Chapter 4--Natural Ventilation natural ventilation forces, in accordance with the requirements of build ing occupancy. The types of openings may be classified as: 1. Windows, doors, monitor openings, and skylights. 2. Roof ventilators. 3. Stacks connecting to registers. 4. Specially designed inlet or outlet openings. Windows, Doors and Skylights ventilating area when open.^Thrir Fig. 1. The Jump of Wind from Windward Face op Building. (A--Length of Suction Area; B--Point of Maximum Intensity of Suction; C--Point of Maximum Pressure) , ' various ways; they may open by sliding as in the ordinary double-hung windows, by tilting on horizontal pivots at or near the center, or by swinging on pivots at the top or bottom. Whatever the form and type of window used, the amount of clear area that can be made available is the factor of greatest importance in ventilation.. All types of sash (double-hung, top, center or bottom horizontal pivoted, or vertical.pivoted) have about the same air flow capacity for the same clear area. Air leakage through closed windows is important during high winds (Chapter 6). , 91 American Society of Heating and Ventilating Engineers Guide, 1936 The proper distribution of air in occupied spaces is an element almost as important as that of sufficient air quantify. Advantageous pivoting of sash is very useful for. securing good air distribution. Deflectors are some times used for the same purpose, and these devices should be considered a part of the ventilation system. . Door openings are seldom included in the ventilation calculations, though they may be of great value for extreme summer conditions, and should be considered in this connection as well as in garage design. Skylight and monitor openings are of importance as .these and the roof ventilators are outlets, while the loyrer windows are usually inlets on the windward side and outlets on the leeward side. In general the areas of inlets and of outlets should be about equal. It is-important to make a check on this ratio in any installation, as any great excess of area of one set of openings over another means waste opening area. The operating devices used for sash, monitors, skylights and roof ventilators should be well selected as poor operating devices may defeat the entire design. Roof Ventilators The function of a roof ventilator is to provide a storm and weather proof air outlet, which is sensitive to wind action for producing additional flow capacity, and at the same time is subject to manual or automatic control by suitable dampers. The capacity of a ventilator at a constant wind velocity and temperature difference, depends upon four things: (1) its location on the roof, (2) the resistance it offers to air flow, (3) the area and location of openings provided for air inflow at a lower level, and (4) the ability of the ventilator head to utilize, the kinetic energy of the wind for inducing flow by centrifugal or ejector action. Frequently one or more of these capacity factors is overlooked in a ventilator installation. For maximum flow induction, a ventilator should be located on that part of the roof which receives the full wind without interference. (See Fig. 1.) This does not mean that no ventilators are to be installed within the suction region created by the wind jumping over the building, or in a light court, or on a low building-between two high buildings. Ventilators are highly effective in such low-pressure areas, but .their ejector action, caused by wind velocity, is of little importance in these locations, and hence their size should be increased proportionally. Ventilator resistance depends on (1) type of inlet, (2) area of openings and passages, and (3) number of turns or changes of direction of the air flow. The inlet grille, if any, should have ample free area, and the venti lator should always be provided with a taper-cone inlet in order to produce the effect of a bell-mouth nozzle (flow coefficient 0,97) rather than that of a square-entrance orifice (flow coefficient 0.60). In other words, the grilles should be oversize as compared with the ventilator, and they should be connected by tapering collars. If the ventilator head . construction produces changes in the direction of air flow, the area of the flow passages should be increased accordingly. i . Air inlet openings at lower levels in the building are of course necessary for the economical use of ventilator capacity. ;The inlet openings should be at least equal to, and preferably twice as great as the combined throat areas of all roof ventilators. The air discharged by a roof ventilator 92 Chapter 4--Natural Ventilation a d on wind velocity and temperature difference, but due to. the four depen s ^actors already mentioned, no simple formula can be devised for exoreCssmg ventilator capacity. q verafitypes of roof ventilators are shown in Figs. 2 to 11. These may , Hassified as stationary, Figs. 2 to 6, pivoted or oscillating, Figs. 7 to 9, DC elating Figs. 10 and 11. When selecting unit ventilators, some attention should be paid to ruggedness of construction, storm-proofing f tures dampers and damper operating mechanisms, possibilities of noise from dampers or other moving parts, and possible maintenance CIt;S'should be kept in mind that a suitable combination of roof venti lators with mechanical ventilation frequently offers the best solution of a ventilating problem. The natural ventilation units may be used to sup plement power driven supply fans, and under favorable weather con ditions it may be possible to shut down the power driven units. Where low operating costs are very important, such a combination has great advantages. Roof ventilators with built-in electric fans are attracting . increased attention because they combine the advantages of low instal lation and operating cost with those of continuous service. Controls In connection with any combination between natural and fan venti lation, the controls are of importance. Both the fans and the ventilator dampers may be controlled by some combination of three methods: (1) hand operation, (2) thermostat operation, and (3) control by wind velocity. The thermostat station may be located anywhere in the building, or it may be located within the ventilator itself. The purpose of wind velocity control is to obtain a definite volume of exhaust regardless of the natural forces, the fan motor being energized when the natural exhaust capacity falls below a certain minimum, and again shut off when the wind velocity rises to the point where this minimum volume can be supplied by natural forces. Stacks Stacks are really chimneys and utilize both the inductive effect of the wind and the force of temperature difference (the so-called gravity action). While their openings projecting above the roof are not provided with any special construction for developing suction by the action of the wind, the plain vertical opening is also effective in this respect. Like the roof ventilator, the stack outlet should be located so that the wind may act upon it from any direction. Stacks are applicable particularly in the case of schools, apartments, residences and small office buildings. Partitions interfere with , general air circulation, and some type of outlet from each room is necessary. If the building is not too tall, and the requirements of occupancy are moder ate, a system of stacks with registers in each room may be more eco nomical than a system of mechanical ventilation employing fans. In making the comparison, however,' the building space occupied by the stacks should be considered. . With little or no wind, chimney effect or temperature difference will produce outflow through, the stacks and an equal inflow through windows 93 - . A^g^NSocmT of Heating and Venting-EngiNEE^^T1^7 Chapter 4--Natural Ventilation in all sides of the building. With wind, the inductive force at the top of ventilating shafts is more powerful than that on the leeward side of the building, so that air is drawn in through leeward openings by a combina tion of the forces of wind and temperature difference. On the windward side, the direct forcing pressure of the wind is of course added to the temperature difference effect. Thus forces are available for causing in flow at practically every window of such a building. Adequacy of stack size must, of course, be provided. PBINCIPLES OF AIR FLOW CONTROL The air flow through a ventilation opening depends on the two factors already discussed, namely, (1) the natural forces available, (2) the open ings available, and the resistance to flow offered by these openings. The design problem includes, of course, a determination of the desired air Fig. 10. Rotating Ventilators quantity and distribution in order that the openings may be properly placed. The purpose of ventilation is to carry off either excess heat or air impurities, and the desired air quantities depend upon the amount of heat or of impurities present. The amount of heat can be determined, in the case of forge shops for example,, from the amount of fuel burned, which in turn is based upon the production capacity for which the building is being designed. In the case of foundries, the heat given off by the metal in cooling from the molten state can be used. In some instances, not all of the heat may be dissipated to the air, but a fair estimate of the amount to be removed by the air can usually be made. The next step is to select the temperature difference to be maintained. Knowing the amount of heat to be removed and having selected a desirable temperature difference, the amount of air to be passed through the building per minute to maintain this temperature difference can be determined by means of the following equation: where H cQD V (3) c = 0.24 = specific heat of air. V = specific volume of the air, cubic feet per pound, about 13.5. (See Chapter 1.) 94 95 of andAmerican Society Heating Ventilating Engineers Guide, 1956 H = heat to be carried off, in Btu per minute. Q -- air flow in cubic feet per minute. D = inlet-outlet temperature difference in degrees Fahrenheit. ; For disposing of air impurities, the required air flow must be such that the outside air will dilute the impurities to a degree that they are no longer objectionable. For human occupancy, such as in auditoriums and classrooms, 10 cfm per person is usually taken as the minimum of outside air necessary for ventilation (see Chapter 3).' For garage ventilation, sufficient air must be admitted to dilute the carbon monoxide content of the indoor air to 1 in 10,000 (see Garage Ventilation in this Chapter). Air quantity and quality are not the only requirements. For human occupancy, air distribution is important. In ventilation the air distribu tion is almost entirely a matter of the number, the design, and the location of inlets and outlets. In locating openings, special precautions should be taken against the formation of dead air spaces or pockets within the zone of occupancy. Suggested methods for estimating the air flow due to temperature difference alone and to wind alone have already been given. 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 same openings have been assumed in both' cases, and since the resistance to flow through the openings varies ap proximately with the square of the velocity3, this resistance becomes a limiting factor as the flow through the openings is increased. Recent investigations1-2 show that the total flow is only 10 per cent above the flow caused by the greater force when the two forces are nearly equal, and this percentage decreases rapidly as one force increases above the other. Tests on roof ventilators indicate that this is too conservative in the direction of low total flow quantities, but there is in any case a large judgment factor involved. The wind velocity and direction, the outdoor temperature, or the indoor activities cannot be predicted with certainty, and great refinement in calculations is therefore not justified. When designing for winter conditions, an added variable is the heat lost by direct flow through walls and windows and by infiltration. Example 1. Assume a drop forge shop, 200 ft long, 100 ft wide, and 30 ft high. The cubical content is 600,000 cu ft, and the height of the air outlet over that of the inlet is 30 ft. Oil fuel of 18,000 Btu per lb is used in this shop at the rate of 15 gal per hour (7.75 lb per gal). Temperature differences are 10 F in summer and 30 F in winter; and the wind velocity is 5 mph in summer and 8 mph in winter. What is the necessary area for the inlets and outlets, and what is the rate of air flow through the building? , Solution. The system must be designed for the summer conditions as these are the more severe. The heat to be removed per minute is: H ~60 X 7.75 X 18,000 = 34,875 Btu. ,,. By Equation 3, the air flow required to remove this heat with a temperature difference of 10 deg is: Q= VH cD _ 13.5 X 34,875 = 196,172 cfm' 0.24 X 10 rrttfs is true for cvrbuUni flow only. It would be more correct to state that the resistance varies approxi mately with ysfor high to moderate velocities, with Vi- for moderate to low velocities, and with the first power of the velocity for very low velocities through small openings. ` 96 A Chapter 4--Natural Ventilation . uaj to 19-6 air changes per hour. The assumption is made that the average This is eq (jjfjerence between indoors and outdoors is the same as the temperature rise Th?^r from the inlet opening to the outlet opening. Actually, the latter difference is i r and so the value of 19.6 air changes per hour is conservative as it allows for more Cooling than is necessary for an average temperature difference of 10 deg. rr iQfi 172 cfm areto be circulated by the force of the temperature difference alone, the area of opening would be, by Equation 2: <2________ 196,172 A = oaV~h~[i7 ~ 9.4 V30 x io ~ 1,205^ft' If this area of openings were provided, a wind velocity of 5 mph, acting alone, would produce a flow according to Equation 1, of: <2 = EAV = 0.50 X 1,205 X 5 X 88 = 265,100 cfm. If the inlet openings do not face the wind, but are at an angle with it, about half this amount may be considered to flow. A factor of judgment must now be exercised in making the selection of the area of openings to be specified. Apparently 1205 sq ft are a very generous allowance because either a direct wind of 5 mph or an average temperature difference of 10 deg acting alone will more than suffice to carry away the heat, and when the two forces are acting together, the system may have an excess capacity of 25 per cent to 50 per cent, especially if the outlets are made up partially of roof ventilators which employ the force of the wind for producing a suction effect. On the other hand, the wind may at times come from an unfavorable direction, or its velocity may fall below 5 mph or the building construction may not permit a full 2400. sq ft of inlet window area and an equal amount of monitor or roof ventilator outlet area. In case the two sets of openings are not equal, their effectiveness is reduced. From this example it must be apparent that while formulas may furnish a reliable guide, the final solution of a problem of natural venti lation requires a common sense analysis of local conditions to supplement and to modify the dictates of the formulas. GENERAL RULES A few of the important requirements in addition to those already outlined are: 1. Inlet openings should be well distributed, and should be located on the windward side near the bottom, while outlet openings are located on the leeward side near the top. Outside air will then be supplied to the zone of occupancy. 2. Direct short circuits between openings on two sides at a high level may clear the air at that level without producing any appreciable ventilation at the level of occupancy. ventilators should be located 20 to 40 ft apart each way and preferably on the ridge of the roof. The closer spacings are used when ventilating rooms with low ceilings. 4. Greatest flow per square foot of total opening is obtained by using inlet and outlet openmgs of nearly equal areas. . a-n /"dustrial building where furnaces, that give off heat and fumes, are to be. ' a -ri.11 ls ketter to locate them in the end of the building exposed to the prevailing wind. 1 he strong suction effect of the wind at the roof near the windward end will then cooperate with temperature difference, to provide for the most active and satisfactory removal of the heat and gas laden air. . 97 American Society of Heating and Ventilating Engineers Guide, 1936 Chapter 4--Natural Ventilation 6. In case it is impossible to locate furnaces in the windward end, that part of the building in which they are to be located should be built higher than the rest, so that the wind, in splashing therefrom will create a suction. The additional height also increases the effect of temperature difference to cooperate with the wind. 7. 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 result in cooperation of wind and temperature difference. 8. In order that the force of temperature difference may operate to maximum advan' tage, 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 ventilation. 9. In order that temperature difference may produce a motive force, there must be vertical distance between openings. That is, if there are a number of openings available in a building, but all are at the same level, there will be no motive head produced by temperature difference, no matter how great that difference might be. 10. In the design of window ventilated buildings, where the direction of the wind i& 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 of the force of the wind. On the other hand, where the direction of the wind is quite variable, it may be stated as a general principle that windows should be arranged in sidewalls and monitors so that there will be approximately equal area' on all sides. Thus, no matter what the wind's direction, there will always be some openings directly exposed to. the pressure' force of the wind, and others opposed to a suction force, and effective movement through the building will be assured. 11. The intensity of suction or the vacuum produced by the jump of the wind is greatest just back of the building face. The area of suction does not vary with the wind velocity, but the flow due to suction is directly proportional to wind velocity. 12. Openings much larger than the calculated areas are sometimes desirable, especially when changes in occupancy are possible, or to provide for extremely hot days.' In the former case, free openings should be located at the level of occupancy for psychological reasons. . Use a small (4 in.) low-speed anemometer, and correct all readings ording to a recent calibration. Mount the anemometer in a strap iron aPc wjth a long handle for convenience. Divide each opening into S. gQUares (by string or wire) and hold the anemometer in the center of 3 Vh square for a definite period of from 15 to 30 seconds. Record the ult of the traverse as soon as completed and start another one im mediately. A series of traverses over a period of one hour, or the full period covered by the wind velocity observations with a fairly steady wind may be considered a satisfactory test for that wind velocity. It is eferable to have an anemometer observer at each opening. If the opening is covered by a grille or register, use the proper correction factors (see Chapter 43). Outdoor Temperature. It is easy to. make an error of 1 to 5 deg in observing the outdoor air temperature. An accurate thermometer, calibrated in 1 deg divisions should be used. The thermometer should be mounted in the shade at about mid-height of the building and not too near the building wall or adjacent to an air outlet. The heat from a wall or roof which has been exposed to the sun is easily transmitted to a thermometer, with resulting high readings. Average Indoor Temperature. It is important to note that the capacity of an opening (such as roof ventilator) does not depend on the difference in the temperatures measured adjacent to the opening. It depends rather on the difference between the average temperature of the column of air inside the building and that outside. Indoor temperatures should therefore be observed at various heights to secure a good average. 13. Special consideration should be given to the possibility, of sidewall or monitor ( windows being closed on account of weather conditions. Such possibilities favor roof DAIRY BARN VENTILATION4 ventilators and specially designed stormproof inlets. A successful barn ventilating system is one which continuously supplies MEASUREMENT OF NATURAL AIR FLOW the proper amount of air required by the stock, with proper distribution and without drafts, and one which removes the excessive heat, moisture, The determination of the performance of any ventilating system involves measurements which are not easy to make. The difficulties are and odors, and maintains the air at a proper temperature, relative humidity, and degree of cleanliness. increased in the case of natural ventilation,.since the motive forces and Barn temperatures below freezing and above 80 F affect milk produc the air velocities are very small. The measurements necessary for giving tion. Milk producing stock should be kept in a bam temperature be the capacity of a system are (1) velocity of the wind, (2) velocity of the tween ib and 50 F. Dry stock, at reduced feeding, may be kept in a barn air through inlet and outlet openings, (3) outdoor air temperature, and 5 to 10 deg higher. Calf barns are generally kept at 60 F, while hospital (4) average indoor air temperature. and maternity barns usually have a temperature of 60 F or somewhat Measuring Wind Velocity. The cup-type of anemometer as used for higher. Weather Bureau observations is sufficiently accurate for this measure The heat produced by a cow of an average weight of 1000 lb may be ment. Some more accurate instruments as well as direct-reading types taken as 3000 Btu per hour. The average rate of moisture production by have been developed for airport service, but for ventilation work it is the a cow giving 20 lb of milk per day is 15 lb of water per day, or 4375 grains average wind velocity over a long period which determines the capacity of per hour.. To set a standard of permissible relative humidity for cow- the system. Hence the use of the Weather Bureau instrument, with an barns is difficulty For 45 F an average relative humidity of 80 per cent observation period of one hour or more, is satisfactory. If observations is satisfactory; with 85 per cent as a limit. of wind direction are required, these should be taken by observing a Where the barn volume is within the limit that can be heated by the sensitive Weather vane at frequent intervals (about every 5 minutes) stabled animals, the air supply need not be heated. The air should be during the same period. Velocity of Air Through Openings. The vane type anemometer is the (teSQI^by Af^A^R^j^fie refer to Technical Bulletin, U. S. Department of Agriculture most practical instrument for this measurement. 98- Dairy Barn Ventilation, by F. L. Fairbanks (A.S.H.V.E. Transactions, Vol. 34, 1928). Cow Barn Ventilation, by Alfred J. OEfner (A.S.H.V.E. Transactions, Vol. 39,1933). 99 __________ ________________________________ a American Society of Heating and Ventilating Engineers Guide, 1936 ; supplied through or near the ceiling. It is better to have the exhaust openings near the floor as larger volumes of warm air are then held in the barn and there is better temperature control with less likelihood of sudden change in barn temperature. .. If a cow weighs 1000 lb and produces 3000 Btu of heat per hour, and jj a bam for the cow has 600 cu ft of air space with 130 sq ft of building exposure, one cow will require 2600 to 3550 cfh of ventilation, depending on the temperature zone in which the barn is located. The permissible heat losses through the structure, based on one cow and depending on the temperature zone, vary between 0.043 and 0.066 Btu per hour per cu ft of barn space, and 0.197 to 0.305 Btu per hour per sq ft of barn exposure. GARAGE VENTILATION5- On account of the hazards resulting from carbon monoxide and other physiologically harmful or combustible gases or vapors in garages, the iimportance of proper ventilation of these buildings cannot be over emphasized. During 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 on extremely cold days the carbon monoxide concentra tion 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 for Heating and Ventilating Garages, adopted in 1929 and revised in 1935, states that natural venti lation may be employed for the ventilation of storage sections where it is practical to maintain open windows or other openings at all times. The code specifies that such openings shall be distributed as. uniformly as pos sible in at least two outside walls, and that the total area of such openings shall be equivalent to at least 5 per cent of the floor area. The code further states that where it is impractical to operate such a system of natural ventilation, a mechanical system shall? be used which shall provide for either the supply of 1' cu ft of air per minute from out-of-doors for each square foot of floor area, or for removing the same amount and discharging it to the outside as a means of flushing the garage. Research .. Research on garage ventilation undertaken by the A.S.H.V.E. Com mittee on Research at Washington University, St. Louis, Mo., and at the Code for Heating and Ventilating Garages (A.S.H.V.E. Transactions,. Vol. 35,1929), (A.S.H.V.E. , Reprint, January, 1935). . . Airation Study of Garages, by W. C. Randall and L. W.`Leonhard (A.S.H.V.E. Transactions, Vol. 30. 1930). . .. Carbon Monoxide Concentration in Garages,.by A. S. Langsdorf and R. R. Tucker (A.S.H.V.E. Trans actions. Vol. 36, 1930). ' Carbon Monoxide Distribution 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). . 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). 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). ' 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). . . 100 q^pter 4--Natural Ventilation University of Kansas, Lawrence, Kans., in cooperation with the A.S H V.E. Research Laboratory, and at the A.S.H.V.E. Research Laboratory has resulted in authoritative papers on the subject. Some of the conclusions from work at the Laboratory are listed below: 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 o( air change and a smaller heating load are required with upward tha3n. wIniththdeoawvnewraagred cvaesnetuilaptwioanrd. ventilation results in a lower concentration of carbon monoxide in the occupied portion of a garage than is had with complete 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 varv from -r. -n. an average rate of 35 cfh. PROBLEMS IN PRACTICE 1 What factors may make the adoption of a system of ventilation depending upon wind movement inadvisable in new construction? o." Variation in direction of wind. . .. b. Variation in wind velocity. c. Inability to clean incoming air. d. Inability to control location, size and shape of buildings on adjacent property. e. Unsatisfactory warming of incoming air during cold weather. . 2 a. What factors are important in the location and control of ventilating openbi.ngWs?hat types of ventilating opening' s are best suited to a proper distribu tion of the air supplied? . a. The proper distribution of air as required by the occupants, and the best utilization of natural ventilating forces. The general rules on page 97 apply particularly to these fba.ctWorisn.dows with swinging sash and openings with deflectors may be used to direct air to the points desired. . 3 9 a. What is the best location for ventilating openings? b. How are the sizes of ventilating openings determined for proper air supply? r ' a. Inlet openings should be low and facing the prevailing winds where possible. Outlet openings should be high and on the side opposite the prevailing winds. b. For simple openings use Formula 1 ; Q = EAV and for stacks use Formula 2: Q = 9.4 A \/ H (h -- 4j . The use of these formulae is illustrated in Example 1 of the text of this chapter, and outlet areas should be approximately the same for best results. Iiilet American Society of Heating and Ventilating Eram-., 4 a. What are the advantages of roof ventilators? b. How are proper sizes determined for roof ventilators? a. Roof ventilators offer the best utilization of the inductive force of the wind, and the may be very economically fitted with built-in fans to supply the necessary circulatioi when the force of the wind is not sufficient. b. Because of the many factors affecting the flow through roof ventilators no accurati formula can be given. It is usual practice to make the combined throat area of ai roof ventilators between one-half area and full area of the air inlets as determined bj Formula 1. ' 5 t What methods of control are used in ventilating systems? Hand control, control by a thermostat located in the ventilated space or in the venti lator, or wind velocity control designed to keep the air discharge constant regardless of wind velocity. 6 How is the quantity of air required for a building determined? Sufficient air must be supplied to carry away the heat and impurities generated within a building. The temperature rise and concentration of impurities in the exhaust air must be held within specified limits. (See Example 1.) 7 What measurements are necessary to determine the capacity of a venti lating system? Wind velocity and air velocities through openings, determined by suitable cup anemo-- meters; outdoor air temperatures, measured by a shaded thermometer not near objects heated by the sun or near exhaust air openings; indoor air temperatures, measured at various heights to secure a good average. - 8 How much air must be supplied for dissipating the heat generated in a dairy barn housing 100 cows if the outside temperature is 20 F and the inside temperature is to be maintained at 45 F? The total heat generated is 100 X 3000 = 300,000 Btu per hour or 5,000 Btu per minute. Then from Formula 3, . v CD _ 5000 X 13.5 0.24 X (45 - 20) = 11,250 cu ft per minute. This amount of air should also keep down humidity and odors. 9 a.. What precaution is necessary in the ventilation of garages using natural ventilation? ' b. How much window area is required for a garage with 50 x 100 sq ft Boor area if natural ventilation is used? . . . The carbon monoxide content of the air should be kept below 1 part in 10,000 and windows should be kept open at all times. . The window area should aggregate 5 per cent of the floor area. . , 0.05 X 60 X 100 = 250 sq ft of window area. This area should be evenly distributed along two sides of the building. . .... Chapter 5 HEAT TRANSMISSION COEFFICIENTS ANB TABLES Heat Transfer, Calculations for Transmission Losses, Areas Where Transmission Losses Occur, Coefficients of Transmission, Table of Conductivities and Conductances, Tables of Over-all Coefficients of Heat Transferfor Typical Building Constructions TO maintain specified inside temperature conditions and determine the type of plant required, it is essential to know the transmission losses of a structure and consider them in conjunction with the infiltration losses. Whenever a difference in temperature exists between the two sides of any structural material, such as a wall or roof of a building, a transfer of ' heat takes place through that material. When the inside temperature is the higher, heat enters the inside surface of the wall by radiation, con duction and convection, because the air and objects within the building are always warmer than the inside surface of the wall when the inside air temperature l is greater than the outside air temperature t0. This heat must then pass through the material of the wall from the inside to the outside surface, and is finally given off from the outside surface by radiation, conduction and convection, provided, of course, that equi librium has been established and all four temperatures are constant. If the outside temperature is the higher, the reverse process takes place. CALCULATIONS FOR TRANSMISSION LOSSES The calculations for heat transmission losses are made by multiplying the area A in square feet of wall, glass, roof, floor, or material through which the loss takes place, by the proper coefficient U for such construc tion or material and by the temperature difference between the inside air temperature t at the proper level (in many cases not the breathing-line) and the outside air temperature tQ. Therefore, where fft = AV(t -io) (l) Ht =.Btu per hour transmitted through the material of the wall, glass, roof or Boor. A = area in square feet of wall, glass, roof, floor, or material, taken from building plans or actually measured. (Use the net inside or heated surface dimensions in all cases.) . 1~ = temperature difference between inside and outside air, in which t must always be taken at the proper level. Note that t may not be the breathing-line . temperature in all cases. 103 X of andAmerican Society Heating Ventilating Engineers Guide, 1936 ._ i Heat is lost from a building by transmission through parts of the structure which separate heated spaces from the outside air or fron, unheated colder spaces within the building. In general, five parts are', involved: (1) outside walls; (2) outside glass; (3) inside walls or parti-i tions next to unheated spaces; (4) ceilings of upper floors, either below a: cold attic space or as the underside of a roof slab; and (5) floors of heated rooms above an unheated space.. 1 The net inside wall surface is usually determined by reference to the: scale plans and elevations of the building concerned. In some cases, of course, the actual building may have to be measured. The total area of ' all outside openings which are occupied by windows and doors is accurately' measured and listed as glass. The glass area is then deducted from the total outside wall area for each room and the difference is the net wall area. If there are no partitions, measure from the inside face of one wall to the inside face of the next wall. The areas of walls, ceilings and floors next to cold or unheated spaces are found, of course, by taking the inside dimensions of such areas, measured on the heated side. COEFFICIENTS OF TRANSMISSION The coefficients of transmission may be determined by means of the ' , guarded hot box or the Nicholls heat meter described in Chapter 43, or they may be calculated from fundamental constants. Because of the i unlimited number of combinations of building materials, it would be impractical to attempt to determine by test the heat transmission co efficient of every type of construction in use; consequently, in most cases' it is advisable to calculate these coefficients. Symbols The following symbols are used in the heat transmission formulae in. this chapter: Z7 = thermal transmittance or over-all coefficient of heat transmission; the amount of heat expressed in Btu transmitted in one hour per square foot of the wall, floor, roof or ceiling for a difference in temperature of 1 deg F between the air on the inside and that on the outside of the wall, floor, roof or ceiling. , k = thermal conductivity; the amount of heat expressed in Btu transmitted in one hour through 1 sq ft of a homogeneous material 1 in. thick for a difference in temperature of 1 deg F between the two surfaces of the material. The conductivity of any material depends on the structure of the material and its density. Heavy or dense materials, the weight of which per cubic foot is high, usually transmit more heat than light or less dense materials, the weight of which per cubic foot is low. C = thermal conductance; the amount of heat expressed in Btu transmitted in one hour through 1 sq ft of a non-homogeneous material for the thickness or type under consideration for a difference in temperature of 1 deg F between the two surfaces of the material. Conductance is usually used to designate the heat transmitted through such heterogeneous materials as plaster board and hollow clay tile. '' / = film or surface conductance; the amount of heat expressed in Btu transmitted by radiation, conduction and convection from a surface to the air surrounding it, or vice versa, in one hour per square foot of the surface for a difference in temperature of 1 deg F between the surface and the surrounding air. To differentiate between inside and outside wall (or floor, roof or ceiling) surfaces, fi is used to designate the inside film or surface conductance and fQ the outside film or surface conductance. a = thermal conductance of an air space; the amount of heat expressed in Btu trans . mitted by radiation, conduction and convection in one hour through an area of 1 sq ft of. 104 Chapter 5 Heat Transmission Coeppicients~^d Tab^~~~~~-- adthenepaeminradsstpeoarincaeltshfoeenrmcaleotasenimngapbiets.roaltuutreetedmiffepreernactuereo,/ tlhed:ewgidF1th. Ttthhheeo rS)A-"CtanSe of position and the an a'> space character of 7? = resistance or resistivity which is the reciororaI . ' or conductivity, t.e.: P ocal of transmission, conductance, ' JL = over-all or air-to-air resistance. u i = internal resistivity. k. _L internal resistance. c j_ = film or surface resistance; / --a- = air-sp:ace resistance. ; .. ' Fundamental Formulae The formula of the over-all coefficient for a simple wall x inches thick is : U = J_ + JL + Jl fi + * + fo : (2) and for a compound wall of several materials having thicknesses iff inches of Xi. Xj, *i, etc., the coefficient is: ' :\ ; V= T+-sr + t+t + ir+-"- (3) In the case of air-space construction, an air-space coefficient for each air space must be inserted in either Equation 2 or 3. Thus for a simple wall with one air space, V =* +-L fi kt a kt fo (4) and for a wall of several air spaces having conductances of dlt dt, a3, etc., the coefficient is: ' - ,- - ;1 U = J_ , _5l_l _L + A+--4. A+.L + dt. fi ki i hj Oj kt Ot kt fo , . (5) With certain special forms of materials which have irregular air spaces (such as hollow tile) or are Otherwise non-homogeneous, it is necessary to use the conductance (C) for the unit construction,. in which case is replaced by ... . . As in the case of the simple wallp./i : and ./0: are. always the inside ,and outside surface coefficients'for the twb'materials in Contact with air. If 105 I of andAmerican Society Heating Ventilating Engineers Guide, 1935 the air is still (no wind), then for the same material f; and fa are the same,' and/i = /0; but if the outside air is in motion, then f0 is always greaftj than fi and will increase as the wind velocity increases. Values for/j jt still and moving air have been determined for various building materials at the University of Minnesota under a cooperative research agreement with the Society1. The range of values for ordinary building materials is comparatively small and for practical purposes may be assumed constant for either still air or any given wind velocity, particularly in view of the' fact that the surface resistances usually comprise only a small part of the total resistance of the construction, except in the case of thin, highly, conductive walls. In determining basic heat transmission values f^J building construction, it is customary to use that value of f0 which will occur when a 15-mph wind blows parallel to the outer surfaces considered. Table I. Conductances of Air Spaces a at Various Mean Temperatures Temp ` Dso Fahb 0.128 Conductances or Air Spaces fob Various Widths in Inches - 0.250 0.364 0.493 0.713 1.00 1.500 20 2.300 1.370 1.180 1.100 1.040 1.030 1.022 30 2.385 1.425 1.234 1.148 1.080 1.070 1.065 40 2.470 1.480 1.288 1.193 1.125 1.112 1.105 50 2.560 1.535 . 1.340 1.242 1.168 1.152 1.149 60 2.6S0 1.590 1.390 1.295 1.210 - 1.195 1.188 70 2.730 1.648 1.440 1.340 1.250 1.240 1.228 80 2.819 1.702 1.492 1.390 1.295 1.280 1.270 90 2.908 1.757 1.547 1.433 1.340 1.320 1.310 100 2.990 1.813 1.600 1.486 1.380 1.362 1.350 no 3.078 1.870 1.650 1.534 1.425 1.402 1.392 120 3.167 1.928 1.700 1.580 1.467 1.445 1.435 130 3.250 1.980 1.750 1.630 1.510 1.485 1.475 140 3.340 2.035 1.800 1.680 1.550 1.530 1.519 150 3.425 2.090 1.852 1.728 1.592 1.569 1.559 ^Thermal Resistance of Air Spaces, by F. B. Rowley and A. B, Aigren (A.S.H.V.E. Transactions, VoL 35, 1929), The conductances of air spaces at various mean temperatures and widths,, for ordinary building materials, are given in Table 1. These results were likewise obtained at the University of Minnesota under a co operative research agreement 'with the Society. Values for k and C, the conductivity and conductance of building ma terials and insulations, are given in Table 2 as taken from the published values of various investigators. It should be noted that values of k and C as well as of U are dependent on the mean temperature, and it is; therefore desirable that the investigator determine heat-transmission values under conditions approximating those existing under actual con ditions. Recommended values for calculating the coefficients of trans mission of various types of construction are marked by an asterisk in Table 2. - Surface Conductances as Affected by Air Velocity, Temperature and Character of Surface, by F. B. Rowley, A. B. Aigren and J. L. Blackshaw (A.S.H.V.E. Transactions Vol. 36, 1930). See also reference* at end of chapter; ` 106 ------------------ hpat Transmission Coefficients and Tables Chapter 5--__________ ______ _>--:--:--------------------------- '------------- t.ble 2 Conductivities (k) and Conductances (O of Building lA ' Materials and Insulators -. - ,,, expressed in Blu per hour per square foot per degree Fahrenheit Per 1 in. thickness, The coefiiLients are exTresw unless otherwise indicated. ^^ -4 O Material Description U* P o E-B 5 aS if fkc ss8 s* 6G p- p aj O1o Ogo gsS gg 1& PoS < ' Curota Blocks1 _ Concrete------- Concrete Blocxb*Stons.. Tile------ Ton or Teftaano-.'.-- Common---~ Face-- ------ -- Damp or wetTypicaL--------- TypicalTypical (8 in.). * (12 in.)- Typical---- -.2-4 mix. Various ages and mix,<-. -- uo.o 143.0 Cellular- 40.0 50.0 60.0 70.0 Typical gypsum fiber concrete, 87-5% gypsum and 12.5% wood chips Special concrete made with, an aggregate of hardened clay--1-2-3 mix. 51.2 101.0 Typical (8 in,). - (12 in.)--------------------------------------- Special concrete block made with an aggre gate of hardened clay--4 x 8 x 16 in., 3 cores, 18% vniHw--... -- , bpem&l ooncrese oioca inaut? mui tu> o^iv- gate of hardened clay--8 x 8 x 16 in., 4 cores, 35% voids------------------- , TypicaL--------------------------- -------- -- 74.0 74.5 Typical hollow clay (4 ini)--. J * " (6 in.)*..- ` nlioni.n).').*.. - * (12 in.)*. . " (16 in.)*. Hollow gypsum (4 in.)Solid gypsum--------- --- Solid t ) 120.0 s 127.0 124.3 _ 51.8 - 75.6 - 75 _. _ 69 __ 75 75 75 75 74 70 _ ~ - 110 100 105 70 76 s.oo* 9.20* 5.00* 12.00* 5.20* 0.62t* 0.5lf* 12.00* 9.46 11.35 to 16.36 1.06 1.44 1.80 2.18 1.66* 3.98 l.OOf O.SOf* 0.66t 0.30t 12.50* 12.00* 1.00 0.64 0.60 0.5S 0.40 * 0.31 * 1.00 0.60 0.47 0.46 * 1.66 2.96 12.00* 0.20 0.11 0.20 0.08 0.19 1.61 1.96 0.08 0.11 -- 0.94 0.69 0.56 0.46 0.60 0.25 1.00 1.25 1.51 3.33 0.08 0.08 1.00 1.57 1.67 1.72 2.50 3.23 1.00 1.67 2.13 2.18 0.60 0.34 0.08 (2) (3) -- -- .. w (5) (3) 3 (3) (3) (4) (3) -- -- (3) (3) _ -- _ _ -- _ __ ( (2) (2) (}> (4) *--* Authorities: 8. Bareau of Standards, tests based on samples submitted by manufacturers. A. C. Willard, L. C. Iichty, and L. A. Harding, tests conducted at the University of Illinois. *J. C. Peebles, tests conducted at Armour Institute of Technology, based on samples submitted by manufacturers. *F. B. Rowley, testa conducted at the University of Minnesota. . A.S.H.V.E. Research Laboratory. . . E. A. Allcat, tests conducted at the University of Toronto. 'Lees and Choriton. Recommended conductivities and conductances for computing heat transmission coefficients. tFor thickness stated or used on construction, not per 1-in. thickness. For additional conductivity data see Table 14, Page 63,1984 A.S.RJ?. Data Book. `Recommended value. See Stating. Ventilating and Air Conditioning, by Harding and Willard, revised edition, 1932. One air cell in the direction of heat flow. *See A&H.V.E. Research Paper, Conductivity of Concrete, by F. C. Houghten and Carl Gatherlet (A.SJLV.E. Trans actions, VoL 37, 1931). . Ths 64m., 8-in., and 10-in. hollow tile figures are baaed on two ceflq in the direction of heat flow. The 12-in. hollow tile is based on three cells in the direction of heat flow. The 16-in. hollow tile consists ofone 10-ia. and one 6-in. tile, each having ,w> 4L. 4^.__L..* ei. /Not compressed. - Hoofing, 0.15-in. thick (1.34 lb per sq ft), covered with gravel (0.83 lb per sq ft), oombined thickness assumed 0.25. 107 . . , ' ' . of andAmerican Society Heating Ventilating Engineers Guide, 1935 Table 2. ^Conductivities (k) and Conductances (C) of Building Materials and' Insulators--Continued The coefficients are expressed in Btu per hour Per square foot per degree Fahrenheit per 1 in. thickness unless otherwise indicated. ' ' Material INSULATION--BLANKET or flexible types INSULATION--SEMIRIGID TYPE Description: - ' CPJ l! a? no. Chemically treated wood fibers held between Eel grass between strong paper/___________ " * " " " Fabric with non-metallic reflective surface 04 in. thick) ____ ______ Flax fibers between strong paper/________ Chemically treated hog hair between kraft paper/ ........................... Chemically treated hog hair between kraft paper and asbestos paper/ Hair felt between layers of paper/ Kapok between burlap or paper/________ __ Jute fiher/. . 4.60 3.40 4.90 5.76 7.70 il.00 1.00 6.70 JaB5fif K* af sB 90 90 70 90 71 71 75 90 75 3 1-1 lg Pb i o3 ji ii aS 03 8 i; K l < --- 0.27* 0.26 0.25 0.33f. 0.28 0.26 0.28 0.25 0.24 0.25 3.70 3.85 4.00 3.03 3.57 3.85 3.57 4.00 4.17 4.00 - w 'i|| oi I (3) * FIt/ - Flax and rye/_____ Felted hair and asbestos/.. 75% hair and 25% jute/ 50% hair and 50% jute/ * Jnttif Felted int* oHotofi/ Compressed neat moss. ... 11.00 12.10 13.60 7.80 6.30 6.10 6.70 10.00 . 11.00 90 70 90 90 90 90 75 90 70 0.26 0.30 0.32 0.28 0.27 0.26 0.25 0.37 0.26 3.84 (1) 3.33 (3) 3.12 (1) 3.57 * (1) 3.70 (1) 3.85 (1) 4.00 (3) 2.70 (1)i 3.84 (j); INSULATION--LOOSE FILL OR BAT TYPE .Fntmt Glass Wo6l______ ___ Granular________ Sawdiirt...... Made from ceiba fibers/____ . .. ....... . ** * -* - 1.90 1.60 75 75 0.23 0.24 4.35 4.17 (3) (3) Fibrous material made from dolomite and silica ........... Fibrous material made from nla? . Fibrous material 25 to 30 microns in dfa- 1.50 75 9.40 103 0.27 0.27 3.70 3.70 (3) (1) meter, made from virgin bottle clam .. Made from combined silicate of lima and 1.50 7S 0.27 3.70 (3) alumina. .. 4.20 72 0.24 , 4.17 (3) : Made from expanded aluminum-magnesium ailieata . 6.20 42 0.32 3.12 (3) 1.00 (n * *' * Flaked drv and flnffv/ " "* * 24.00 90 0.77 1.30 (a 18.00 90 0.59 . 1.69 , in 12.00 90 0.44 2.27 . (1) : - 34.00 90 0.60 1.67- (11 i 26.00 90 - 0.52 1.92 (11 ' a . 24.00 19.80 75 90 0.48* 0.35 .2.08 2.86 (3) , 0) ' 18.00 75 0.34 2.94 (3) 0.27* 0.31 3.22 (1) '* a aaa 18.00 90 0.30 0.29 j.3-,45 1) U) 14.00 90 10.00 90 0.28 3.57 0.27* 3.70 (i) ii) > Rock wool with a binding agent ' 14.50 77 0.33 3.03 (i) Rock wool with flax, straw duId. and binder 14.50 75 0.38 2.63 (J) |Rock wool with vegetable fibers - 11.50 72 0.31 3.22 (3) 0.41 2.44 (1) ? 5 From maple, beech and birch (coarse) Redwood bark_____________ _____ _ 13.20 90 3.00 90 0.36 0.31 2.78 3.22 (l) INSULATION--RIGID , 7 For notes see Page 107. 108 --r------- Chapter 5--Heat Transmission (Coefficients and Tables o Conductivities (k) and Conductances (C) of Building Table a. Materials and Insulators--Continued .-- The coefficients are expr in Btu per hour, per square foot per degree Fahrenheit pa 1 in. thickness, unless otherwise indicated._____________________ ____________ Material INSOLATION--RKHD --Continued CorsbOARD Fibbr- Descriptton S 5 ebs M ean T emp. (Deo Fabb) p aE a 85 !! i-- sP. eP 11 1S' Esa Ogo Oos No added binder.. Asphaltic binder__ :--.--------------------------- Typing ............... -------------- Core of fiber board coated two sides with nonmetailic reflective surface {*A in. thick)----- Fiber board coated one side with nonmetallic reflective surface ($6 in. thick)-- Made from chemically treated wood fiber.---- Made from chemically treated wood and vegetable fibers--.................... .....-......t-- Chemically treated hog hair covered with film of asphalt Made from corn stalks----------------------------- * " exploded wood fiber-----------------: * " bard wood fibers-----------...... Insulating plaster 9/10-in. thick applied to J^-in. plaster board base------------ ----------Made from licorice roots----------------------Made from 85% magnesia and 15% asbestos Made from shredded wood and cement.-----" " sugar cane fiber----------- -------- Sugar cane fiber insulation blockB encased in asphalt membrane-------------------- ----------Made from wheat straw---------- ----....... " " wood fiber____________ ___ ___ 14.00 10.60 7.00 5.40 14.50 23.4 20.00 25.00 10.00 15.00 17.90 15.20 54.00 16.10 19.30 24.20 13.50 13.80 17.00 15.90 15.00 8.50 15.20 16.90 90 90 90 90 90 -- 70 75 70 75 75 71 78 70 75 81 86 72 70 70 68 72 70 52 72 _ 90 0.34 0.30 0.27 0.25 0.32 0.33* 0.27t 0.49f 0.36 0.38 0.28 0.33 0.32 0.32 ,1.07f 0.34 0.51 0.46 0.33 0.30 0.33 0.33 0.33 0.33 0.29 0.33 0.34 2.94 3.33 3.70 4.00 3,12 3.03 ID a) <u <`i to 3.70 (3) 2.04 0) 2.78 (3) 2.63 (3) 3.57 3.03 3.12 3.12 (3) (3) 4 (3) 0.93 (3) 2.94 (3) 1.96 <l) 2.17 (3) 3.03 . (3) 3.33 3.03 3.03 3.03 3.03 3.45 3.03 2.94 (3) (3) (3) (3) 0) (3) (3) III building boards Asbestos----------------- GrpscrK-- Plabteb Boabd_ Compressed cement and asbestos sheets-... Corrugated asbestos board_____________ Pressed asbestos mill board------------------Sheet asbestos-- Gypsum between layers of heavy pap Rigid, gypsum between layers of paper (J^-in. thick).. Gypsum mixed with sawdust between layers of heavy paper (0.39-in. thick)--...---------- 8titn*.)_ 123.00 20.40 60.50 48.30 62.80 53.50 60.70 -- 86 110 86 110 70 90 90 _ _ ROOFING CONSTRUCTION ROOTING----. SemaLEa. Asphalt, composition or prepared__------- -- Built up--4-m. thick....*_____________ Built up, bitumen and felt, gravel or slag surfaced?______________________ _____-- Plaster board, gypsum fiber concrete and 3-ply roof covering Asphalt-- SlateWood. 70.00 -- --- 52.40 65.00 70.00 201.00 -- 75 -- _ 76 75 75 _ PLPArjSiBTfCETRING M ATERIALS Cement______ -_ Gypsuum, typical Thickn) ess %. ,, in.- Mbtal Lath and Plaster-- Total thickness ^ in_______________ Wood Lath and Plaster.___ plaster, total thickness M in____ For notes see Page 107. 109 73 ---- 70 2.70 0.48 0.84 0.29 1.41 0.37 2.08 1.19 3.45 0.71 2.60f 0.38 3.60| 0.28 3.73f* 0.27 2.82f* ` 0.35 (1) (2) (1) (2) (3) Cl) (1) _ -- 6.50f* 3.53f* 1.33f 0.58f 6.00f* 6.50t* 10.37* 1.28f* 0.15 (3) 0.28 . (2) 1.72 0.17 0.15 0.10 . 0.78 < (3) (73) -- 8.00 0.13 3.30* 0.30 8.80t 0.11 4.40f* 0.23 2.50t* 4 0.40 (2) _ (4) _ (4)  American Society o/ Heating and Ventilating Engineers Guide, 1936'":.! Table 2. Conductivities (k) and Conductances (C) of Building Materials and Insulators--Continued . The coefficients are expressed in Blit Per how per squarefoot Per degree Fahrenheit Per t in. thickness. . unless otherwise indicated. . 110 strips (one au space) in.) between furring of andAmerican Society Heating Ventilating Engineers Guide, Table 3. Coefficients of Transmission (U) of Masonry Walls'* Coejfcctenls are expressed in Btu per hour per square foot per degree Fahrenheit difference in temperature between the air on the two sides and are based on a wind velocity of 15 mph. ' TYPICAL CONSTRUCTION TYPE OP WALL Thickness or Masonbt (Inches) Solid Brick - Based on 4-in. face brick and the remainder common bnck. 8 12 16 5___Heat Transmission Coefficients and Tables INTERIOR FINISH Plaster on wood lath--furred | Plaster (.% In.) on metal lath--furred | Decorated building board (H in-) without plaster--furred Uninsulated Walls o J 1 (0 8a I t a0 S a 11 a * a $ 3j M a "H. o 4 .3 ABCD E Insulated Walls n 1 a ? ao 318 a j '1 1? oa x! SIS.d . Is 3 . PhO "3 5 is 2* 83 41 il nO 2 a. Js PL a Sgfl l!'e -?s Sb 13-sl RJ g ~.S S-g ss 8 s H 3.2 ax g|%* *51 3*K gsstS- PMSva F GH i' J K Plaster (% in.) on metal lath attached to furring strips (2 in.6)--flexible L insulation 0.50 0.36 0.28 0.27 0^20 ft 32 ft 9.5 6.21 0.30 0.24 0.20 0.23 0.19 0.17 0.22 0.19 0.16 0.16 0.24 0.13 0.14 0.12 0.11 0.23 0.19 0.17 0.12 0.11 0.10 0.20 0.17 0.15 Hollow Tile Stucco Exterior Finish. The 8-in. and 10-in. tile figures are based on two cella in the direction of flow of heat. The 12-m. tile is based on three cells in the direcUon of flow of heat. The 16-in. tile consists ol one 10-in. tile and one 6-in. tile each having two cells in the direction of heat flow. 8 10 12 16 0.25 0.24 0.26 0.26 0.22 0.19 0.27 0.27 0.22 0.19 0.26 0.26 0.22 0.19 0.20 0.20 0.17 0.15 0.20 0.19 0.17 0.15 0.15 0.15 0.13 0.12 0.13 0.13 0.12 0.11 0.20 0.20 0.17 0.15 0.11 0.11 0.10 0.097 0.18 0.18 0.16 0.14 Limestone or Sandstone 8 12 16 24 89 W* 11 > 0 71 0.58 0.49 0.37 0.64 0.53 0.45 0.35 0.37 0.33 0.30 0.25 0.39 0.34 0.31 0.26 0'37 0.33 0.30 0.25 0.26 0.24 0.22 0.20 0.25 0.23 0.22 0.19 0.18 0.17 0.16 0.15 0.15 0.14 0.14 , 0.13 0.26 0.24 0.22 0.20 * 0.13 0.13 0.12 0.11 0.23 0.21 0.20 0.18 Concrete ^ These figures may be used with sufficient , accuracy for concrete walls with stucco extenor finish. . 6 10 16 20 0.79 0.62 0.48 0.41 0.70 0.57 0.44 0.39 0.39 0.34 0.29 0.27 0.42 0.37 0.31 0.28 0.39 0.34 0.29 0.27 0.27 0.25 0.22 0.21 0.26 0.24 0.21 0.20 0.19 0.18 0.16 0.15 0.16 0.15 0.14 0113 0.27 0.25 0.22 0.21 0.13 0.13 0.12 0.12 0.23 0.22 0.20 0.18 Hollow Cinder Blocks Based on one air cell in direction of heat flow. Hollow Concrete Blocks . Based on one air cell in direction of heat flow. *Based on the actual thickness of 2-in. furring strips. 112 8 12 . V ` 8. 12 16 \ 17 1 18 ) 19 1 .i 0.42 0.37 0.56 0.49 0.39 0.35 0.52 0.46 0.27 0.25 0.32 0.30 0.28 0.26 0.34 0.32 0.27 0.25 0.32 0.30 0.21 0.19 0.24 0.23 0.20 0.19 0.23 0.22 0.16 0.15 0.17 0.16 0.13 0.13 0.14 0.14 or. 21 0.19 0.24 0.23 0.12 0.11 0.12 0.12 0.19 0.17 0.21 0.20 A waterproof membrane should be provided, between the outer material and the insulation fill1 to preventjmssible wetting by absorption and a subsequent lowering of efficiency. . . - 113 strips (one air space) of andAmerican Society Heating Ventilating Engineers Guide, 1936 Table 4. Coefficients of Transmission (V) of Masonry Walls with Various Types of Veneers Coefficients are expressed in Btn per hour Per square foot per degree Fahrenheit difference in temperature between the air on the two sides and are based on a wind velocity of IS mph. * TYPIPat CONSTRUCTION TYPE OF WALL Facing Backing WinNa: 4 in. Brick Veneer* 4 in. Brick Veneer* 6 in. 10 in 12 in! HoUow Tile- 6 in. 10 in. Concrete 16 in. j 21 3 22 23 c ;___ Heat Transmission Coefficients and Tables }sitriipns.) interior finish WUninsulated alls Insulated Walls Plaster in.) on rigid insulation (1 in.)--furred Plaster (H in-) on walla j Plaster on wood lath--furred *tas 1.O 21 13 Ja9S33 7 Ma swwx s tj a S .2 i i ja 3 "3. Ia 0a J II 0e 'd Ia ii 11 s1 **5 e 3 $3 ll-s 5 s Is zll Is 3g JPUSo ABCD E FGH I J 0.36 0.34 0.34 0.27 0.34 0.26 o!2o (L25 0.25 0.24 0.21 0.24 0.24 0.23 0.20 0.19 0.19 0.19 0.16 0.19 0.18 0.18 0.16 0.16 0.14 0.14 0.13 0.13 0.12 0.12 0.11 0.19 0.19 0.19 0.16 Plaster on metal lath (Jtfin.) attached to furring strips--furred space (over ^ in . wide) faced one side with bright aluminum foil Plaster (%in.) on metal lath attached to furring strips (2 in.*)--rock wool fill (1H in.*)/ KL 0.11 0.11 0.11 0.10 0.17 0.17 0.17 0.15 Plaster in.) on metal lath attached to furring insulation (2 in.*)--flexible between furring ( 0*18 0.39 0.37 0.33 0.30 0.26 0.35 0.31 0.27 0.33 0.30 0.26 0.24 0.22 0.20 0.23 0.22 0.19 0.17 0.16 0.15 0.14 0.14 0.13 0.24 0.22 0.20 0.13 0.12 0.11 0.21 0.20 0.18 4 in. Brick Veneer* 4 in. Brick Veneer* if jJJ; Cinder Blocks12 in! Cncrete Blocks- 4 in. Cut-Stone Veneer* 8 in. 12 in. Common Brick 16 in. 31 i 32 33 * 0.33 0.31 0.30 . 0.42 0.40 0.38 0.24 0.25 0.24 0.22 0.23 . 0.22 0.28 . 0.30 0.28 0.26 0.28 0.26 0.19 0.18 0.21 0.20 0.18 0.17 0.21 0.20 0.14 0.14 0.16 0.15 0.12 0.12 0.13 0.13 o;i9 0.18 0.21 0.20 0.11 0.11 0.12 0.11 0.17 0.16 0.19 0.18 0.37 0.28 0.23 0.35 0.27 0.22 0.25 0.21 0.18 0.26 0.21 0.18 . i 0.25 0.21 0.18 0.19 0.17 0.15 0.19 0.16 0.14 0.15 0.13 0.12 0.13 0.12 0.11 0.19 ` 0.17 0:15 O.U 0.10 0.095 0.17 0.15 0.14 4 in. Cut-Stone Veneer* 6 in. 10 In! Hollow Tile* 12 in. 4 in. Cut-Stone Veneer* 6 in. 10 in. Concrete 16 in. u 35 36 37 i% i 33 39 4 Computed from factors marked by * in Table 2. *Based on the actual thickness of 2-in. furring strips. ^The 6-in., 8-in. and 10-in. tile figures are based on two cells in the direction of heat flow. tile is based on three cells in the direction of heat flow. The 12-in? 114 0.37 0.36 0.35 0.28 0.35 0.34 0.33 0.26 0.25 0.24 0.24 0.20 0.26 0.25 0.25 0.21 0.25 0.24 0.24 0.20 0.20 0.19 0.19 0.17 0.19 0.19 0.18 0.16 0.15 0.15 0.14 0.13 0.13 0.13 0.12 o.u 0.20 0.19 0.19 0.17 O.U 0.11 0.11 0.10 0.18 0.17 0.17 0.15 0.61 0.51 0.41 0.56 0.47 0.38 0.34 0.31 0.26 0.36 0.32 0.28 0.34 0.31 0.26 0.25 0.23 0.20 0.24 0.22 0.20 0.18 0.17 0.15 0.15 0,14 0.13 0.25 0.23 0.21 0.13 0.12 o.n 0.22 0.20 0.18 ^Calculations include cement mortar (H in.) between veneer or fadng and backing. ..........- /aaw ou one air cell in direction of hmt flow. - - .. 'A waterproof membrane should be provided between the outer material and the insulation fill to prevent possible wetting by absorption and a subsequent lowering of efficiency. 115 of andAmerican Society Heating Ventilating Engineers Guide, 1936 1 )Table 5. Coefficients of Transmission (U of Various Types of Frame Construction INTERIOR FINISH These coefficients are expressed tn Btu per hour per square foot per degree Fahrenheit difference tn temperature between the air on the two stdes, and are based on a wind velocity of 15 mph TYPICAL CONSTRUCTION exterior finish TYPE OF SHEATHING 1 in. Wood* Wood Siding or Clapboard X in* Rigid Insulation H .in. Plaster Board N?: 1 No Insolation Between Stoddino Insulation Between Studding 1 3 00 S 1 s 0o S 3 0.25 00 ja & .3 1 0 0 t B 0.26 a 3 ja 'a l wxl o . ss Phw . c 0.25 0 .2 3 3 S a c i .a | |5 S> D 0 ' .2 ` -30 s. *T3 a c -M 2| si "I* J= . .& . E 0.19 0.15 d -a s. ~a 1 od fS 3I <8*3 0O ft, d 11ll - cva |S Ph . . MM- . FG H 0.11 0.19 0.19 Plaster (X in.) on metal lath-- stud space faced one Bide with bright aluminum foil J3 3 S sfl 6.I m 1 is? l-Ii. a0a3F.a a ,.2:9^ Si**ffi 111! J 0.061 0.17 0.23 0.24 0.23 0.1S 0.14 0.11 0.18 0.18 0.060 0.17 *0.31 0.33 0.31 0.22 0.17 0.13 0.23 0.23 0.064 0.20 snctfroniG) ,/TUFA Att/cco Wood Shingles SHEATHING*) Stucco ''S 1 in. Wood* X in. Rigid Insulation* X in. Plaster Board* 1 in. Wood* X in. Rigid Insulation X in. Plaster Board 0.25 0.19 0.24 0.26 0.20 0.25 0.25 0.19 0.24 0.19 0.15 0.19 0.15 0.12 0.15 0.11 0.10 0.11 0.19 0.16 0.19 0.19 0.16 0.19 0.061 6.057 0.061 0.17 0;14 0.17 0.30 0.31 0.27 0.29 0.40 0.43 0.30 ; 0.22 0.27 0.20 0.40 0.26 0.16 0.12 0.16 0.12 0.19 ; 0.14 0:22 0.22 0.21 0.21 0.28 . 0.28 0.064 0.062 0.067 0:20 0.19 0.24 1 in. Wood* Brick/ Veneer X in. Rigid Insulation /KCAIKMG' X in. Plaster Board "Computed from factors marked by * in Table 2, . *These coefficients may also be used with sufficient accuracy for plaster on wood lath or plaster o plaster board. . .< . . ;t . Based on the actual width of 2 by 4 studding, namely. 3% in. . . . .; 116 " 0.27 0.28 0.27 0.20 0.15 0.12 0.21 s ...0.21 0.062 0.18 0.25 0.26 0.25 6.19 0.15 ' 6.11 0; 19 ' 0;26" 0.061 O.lfT 0.35 0.37 0.35 0.24 0.18 . 0.13 0.25 0.25 0.066 0.22 *Yellow pine or fix--actual thickness about H6. in. Furring strips between wood shingles and sheathing. . /Small aif space and mortar between building paper and brick veneer neglected. ; A waterproof membrane should be provided "between the outer material and the insula on prevent possible wetting by absorption and a subsequent lowering of efficiency. andAmerican Society 0/Heating Ventilating Engineers Guide, iqv; Table 6. (U)Coefficients of Transmission of Frame Interior Walls and Partitions Coefficients ere expressed in Bin per hour per sauare foot t>er rleere* Fnhmth+u Jj/Tw, . . th`a"***. < TYPICAL CONSTRUCTION ^LA/TER. Wall No. Single Partition (Finish on One Side op Air Space Studding) Between Studding __ DOUBLE PARTITION 1 Finished on Bora Sides op Studding) GF^ljapkeeomd Between Studding Rock Wool RII* Between Studding Bumble Insulation Between Bright Alumina^ Studding (One Air Foil Space) Type of Wall Wood Lath and Plaster On Studding - 53 0.62 0.34 0.11 0.065 E 0.21 Metal Lath and Plaster* On Studding 54 0.69 0.39 0.11 0.066 0.23 Plaster Board (H in.) and Plaster** On Studding 55 0.61 0.34 0.10 0.065 0.21 34 in. Rigid Insulation and Plaster*4 On Studding 56 0.35 0.18 0.083 0.056 1 in. Rigid Insulation and Plaster* On Studding 0.12 0.066 0.048 0.097 134 in* Corkboard and Plaster** On Studding 0.16 0.081 0.052 0.040 0.070 2 in. Corkboard and Plaster* On Studding 0.063 0.045 0.035 0.057 0.24 0.26 0.24 0.15 0.10 0.073 0.059 Computed from fartors marked by * in Table 2. -Planter on metal lalh assumed -in. tUckT Thickness assumed in. 'Plaster assumed K-in. thick. Table 7. Coefficients of Transmission (V) of Masonry Partitions'- TYPICAL CONSTRUCTION fftfc/Otivfi No. Plain Walls (No Plaster) Walls Plastered on One Sms ' Walls Plastered on Bora Sides Type of Wall 4-ln. Hollow Clay Tile 4-in. Common Brick 4-in. Hollow Gypsum Tile 2-in. Solid Plaster 60 0.45 61 0.50 62 0.30 63 ....... 118 0.42 0.46 . 0.28 1 I ....... 0.40 0;43 0.27 . 0.53 "Chapter 5___Heat Transmission Coefficients and Tables oa 2* 35 S u gj mI 1 US* t s Z 2. Of2P- *4f5"s55* -5 (A Se Z 55 <3 41 S bo, I*.sa S |1 w O-h 2& S V) Z s ST.g H I* Hz w y S h. u o u 00 M i- 1 S % .v3.38 %*&S-B8 > g t%ystUs iliSs J -..3 mm Up BBi0f-3f =3J^ >*tu 8 E z w g 55 119 '5 H bi C *c 8 onS j cs^ o ? E ill a 1 m e "3 "See a 5* 5S`S a ,, ,, "S j 3 IS3 ff-SY 8J Sco-aO *S " gu ill 88 d ST God- oa c 4, 2 ||5 113 vet m8d ?Pe .<TJ.j a of andAmerican Society Heating Ventilating Engineers Guide, 1935 *i*.l3jJ|<s5s fflJ" a NNMN OOOO and are based on s till a ir (no w ind) conditions on both sides. Coefficients are expressed'irtBtu per hour per square fool Per degree Fahrenheit difference in temperature between the a ir on the two sidest T a b l e 9 . C o e f f ic ie n t s o f T r a n s m is s io n (C O o f C o n c r e t e C o n s t r u c t io n F l o o r s a n d C e il in g s ** 3 a 9 .S offfi-g-8 E-Sl jJS-i tol .1 S."g2 ""Scjsg l-g"2 !E^W.9 IIISoaO""-w r-1- cd co NNhh OOOO OOOO O(NCDHOrOtoHO OOOO OOOO e s~ ' e" c>a OlFo, S3*Sj ev 48' .S-o |*p *>.3 a 3 Mg C" k! 4 c>o.*oE 3*,23A i-H <35/ gg-iisl mu*ptx* " V b35o f3ea*2, uc fjy/4 ^ m'o to O 0 W09) 4ZU) - So a?. Ss a, do .O' e.g 'c.s i l-JSSJSlg S* s* 0 cC 120 - '...yjA-'Vi ofAmerican Society Heating and Ventilating Engineers Guide, 1936 Table 11. Coefficients of Transmission (V) of Various Types of Flat Roofs Covered with Built-Up Roofing* TYPICAL CONSTRUCTION Without Ceilings With Metal Lath AND Plaster Ceilings* TYPE OF ROOF DECK TBICEME88 or Roof Decs (Inches) No. JLooriKCj /Tut lapv^ifep IffWWULWAtUlOONN)i U00MN61 corfatTC. /T RooFlNtf, /Till *T/urfo*T/-jk Precast Cement Tile Hf/otAttoff/ S1N4, / COHCAtTt/ lir Concrete Concrete Concrete m IOOPINlNC/aULAflOK/ UuulaTioti ROtFlHj^..... Wood Wood Wood Wood IflJUtrfttOtt/ r/un.y.j rHJTCfic SSO#AfitPp' Ifi/ULAtlon/ M9FIH6A Gypsum Fiber Concrete6 '2 in.) on Plaster Board 'M in.) . Gypsum Fiber Concrete6 (3 in.) on Plaster Board <H in.) Gypsum Fiber Concrete6 (2 in.) on Rigid Insulalation Board (M in.) Gypsum Fiber Concrete6 (2 in.) on Rigid Insula tion Board (fin.) lH/OUATt1/ ntTAt./ yeck tWOUTtOOfIlL, WOFIKtfi p Flat Metal Roofs Coefficient of transmis sion of bare corrugated iron (no roofing) is 1.50 Btu per. hour per, square foot of projected area per degree ' Fahrenheit dif ference in temperature, based on an outside wind velocity of 15 mph. Computed from factors marked by * in Table 2. ^?ne3?S.s.pe?^_actual Wetnesses used in calculations. Gypsum fiber concrete--87K per cent gypsum. 12per cent wood fiber. 2H 3H 2H 3 122 a. -Heat Transmission Coefficients and Tables r-^m^ients are expressed, in Bln.per hour per square foot per (tepee %S* `.suras She ,hs s -Jt1 tws,dcs- American Society of Heating and Ventilating Engineers Guh^Tiqm Chapter 5--Heat Transmission Coefficients and Tables Table 13. Coefficients of Transmission (/) of Doors, Windows and Skylights CcdoeecffrieceieFnatsharerenhbeaitrddiffoenreanmceinmd tveemlopceitryatoufreISbemtwoebe.naIknedaairreinexspidreesasned oinutsBidlenopftehrehdouer. SPeSr n.f,,o,,S>Vikr~tf.iitk,, t A. Windows and Skylights u Single.... DoubleTriple.... -- B. Solid Wood Doors` 1.13". 0.45 0,281"- NoMIHAJj Thickness Inches i 1)4 iH m 2 2)4 3 Actual . . ' Thickness ' Inches D4e 1%6 m 1/4 2J4 2% . V 0.69 0.59 0.52 0.51 -0.46 0.38 0.33 / CSotemBpeuatetidngu.sVinegnCtila=tin1g.1a5ndfoAr iwr oCoodnd;/iitioni1n.g6,5baynHd/aording6.a0nd Willard, revised ed1itio. n 1932* . . gnelIst iasssuthffaictieonf tslyinagclecupraanteest^oo.fusgelastsh,ensaammeelyc.o1e.f1fi3cieBnttuopfetrrahnosumrispseior nsqfuoarrdeofoomotcpoenrtadinSinXg tdhiifnfewSoSoSd between inside and outside air temperatures. ! na ue^w ainwenoe I While most building materials have surfaces which show similar characteristics as far as the transmission of heat is concerned, it is a wella known fact that certain surfaces such as aluminum bronze, gold bronze, aluminum foil, or in fact any metallic, highly polished surface presents a greater resistance to heat transmission than the surface of the average building material. The greater heat resistance of such metallic surfaces is due primarily to their higher reflectivity and consequent lower emissivity of radiant heat. The use of multiple layers of metallic surfaces, combined with air spaces of low resistance, provides a definite insulating effect. Factors2 for air spaces bounded by aluminum foil are given in Tabled. . Coefficients of transmission of various types of wall, ceiling, floor and . roof construction with aluminum insulation can be readily calculated.. The present installation practice indicates that air spaces of in. to \Yi in. are preferred but manufacturers' recommendations should be closely followed in the application of aluminum foil insulation. :, The majority of the conductivities and conductances of the building materials and insulations given in Table 2 were determined by the hot plate method of testing3. Attention is called to the fact that conductivi ties per inch of thickness of materials or insulations do not afford a true basis for comparison, although they are frequently used for that purpose.. m .Insulating Value of Bright Metallic Surfaces, by F. B. Rowley (A.S.H.V.E. Journal Section, Beating, . Piping and Air Conditioning. June, 1934, p. 263). ' .. standard Test Code for Heat Transmission through Walls (A.S.H.V.E. Transactions, Vol. 34, 1928). See also Chapter 43. ' 125 American Society of Heating and Ventilating Engineers Guide, 1936 Correct comparisons should take into consideration many different factors, including conductivities or conductances, thicknesses installed and manner of installation, while the selection of an insulation should also give consideration to structural qualities, as well as to material and application costs. Fire, vermin, and rot resistance are other important factors to be considered when comparing materials. At present there is no universally recognized method of rating insulations. Conductivities and conductances of building materials and insulations are useful to the heating engineer in determining over-all coefficients of heat transmission of walls, floors, roofs and ceilings. Computed Transmission Coefficients Computed heat transmission coefficients of many common types of building construction are given in Tables 3 to 13, inclusive, each con struction being identified by a serial number. For example, the coefficient of.transmission (U) of an 8-in. brick wall and Y2 in. of plaster is 0.46, and the number assigned to a wall of this construction is 1-B, Table 3. Example l. Calculate the coefficient of transmission (U) of an 8-in. brick wall with H in. of plaster applied directly to the interior surface, based on an outside wind exposure of 15 mph. It is assumed that the outside course is of face:brick having a conductivity of 9.20, and that the inside course is of common brick having a conductivity of 5.0, the thicknesses each being 4 in. The conductivity of the plaster is assumed to be 3.3, and the inside and outside surface coefficients are assumed to average 1.65 and 6.00, respectively, for still air and a 15 mph wind velocity. Solution, k (face brick) = 9.20; x 4.0 in.; k (common brick) * 5.0; x = 4.0 in.; k (plaster) = 3.3;* = H in.;/i = 1.65;/0 = 6.0. Therefore, 6.0 T 9.20 t 5.0 T 3.3 T 1.65 1 0.167 + 0.435 + 0.80 + 0.152 + 0.606 = 0.46 Btu per hour per square foot per degree Fahrenheit difference in tempera ture between the air on the two sides. The coefficients in the tables were determined by calculations similar to those shown in Example 1, using Fundamental Formulae 2, 3, 4 and 5 and the values of k (or C),fufQ and a indicated in Table 2. by asterisks. In computing heat transmission coefficients of floors laid directly on the ground (Table 10), only one surface coefficient (/i) is used. For example, the value of. U for a 1-in. yellow pine floor (actual thickness, 25/32 in.) placed directly on 6-in. concrete on the ground, is determined as follows: ~ _J_ 4. 0^781 JM)^ -- 0.48 Bt'u per hour per square foot per degree difference 1.65 + 0.80 + 12.0 _ io temperature between the ground and the air immediately above the floor. The thicknesses upon which the coefficients in Tables 3 to 13, inclusive, are based are as' follows: : Brick veneer...................................................................................... ............ 4 in. Plaster and metal lath % in. 126 "Chapter 5--Heat Transmission Coefficients and Tables Plaster (on wood lath, plasterboard, rigid insulation, board form, or corkboard)------------------------------------ ,---------Slate (roofing)-------------------------------------------------Stucco on wire mesh reinforcing.-----------------------------Tar and gravel or slag-surfaced built-up roofing.-- H in. Vi in. _ 1 in. - % in. 1- in. lumber (S-2-S)....-------------------- ---- --------------------lii-in. lumber (S-2-S)........................................................ 2- in lumber (S-2-S)................................................ ........... 2J4-in. lumber (S-2-S)........................................................ 3- in. lumber (S-2-S)........................................................... 4- in. lumber (S-2-S)........................................... ............... Finish flooring (maple or oak)...... ....... .......................... -2Hi in. -IKe m. - IH in. - 2}4 in. .. 2% in. - %% in. -AKe in- Solid brick walls are based on 4-in. face brick and the remainder common brick. Stucco is assumed to be 1-in. thick on masonry walls. Where metal lath and plaster are specified, the metal lath is neglected. Rigid insulation refers to the so-called board form which may be used structurally, such as for sheathing. Flexible insulation refers to the blankets, quilts or semi-rigid types of insulation. Actual thicknesses of lumber are used in the computations rather than nominal thicknesses. The computations for wood shingle roofs applied over wood stripping are based on 1 by 4 in. wood strips, spaced 2 in. apart. Since no reliable figures are available concerning the conductivity of Spanish and French clay roofing tile, of which there are many varieties, the figures for such types of roofs were taken the same as for slate roofs, as it is probable that the values of U for these two types of roofs will compare favorably. The coefficients of transmission of the pitched roofs in Table 12 apply where the roof is over a heated attic or top floor so the heat passes directly through the roof structure including whatever finish is applied to the underside of the roof rafters. - Combined Coefficients of Transmission If the attic is unheated, the roof Structure and ceiling of the top floor must both be taken into consideration, and the combined coefficient of transmission determined. The formula for calculating the combined coefficient .of transmission of a top-floor ceiling, unheated attic space, and pitched roof, per square foot of roof area, is as follows: where U = Ur X free X(/,+ U Ux = 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. (6) In using this formula, a correction factor must be applied. As the amount of heat transferred through an air space is proportional to the difference of the fourth powers of the absolute temperatures of the surfaces enclosing the air space, a greater amount of heat is absorbed or emitted by radiation by the surfaces enclosing an unheated attic than by the surfaces of a wall or Ceiling in a room under still-air conditions, where the surrounding objects are only slightly higher in temperature than the interior surfaces of the walls and ceiling.- For example, the average . 127 of and 1916American Society Heating Ventilating Engineers Guide, coefficient of a surface in still air is 1.65 Btu per hour per square foot per degree Fahrenheit, whereas the average coefficient of an air space in an outside wall is about 1.10 Btu per hour per square foot per degree Fahren heit difference between the two surfaces, at a mean temperature of 40 F. An air space coefficient of 1.10 is equivalent to a surface coefficient of 2.20 for each of the two surfaces enclosing the air space, where the over-all transmission is computed by using the coefficients of the two surfaces enclosing the air space instead of the coefficient of the air space itself. Hence, in determining the values of UT and C4e to be used in the formula, the coefficients for the surfaces of the roof and ceiling enclosing the attic should be increased to allow for the additional amount of heat transferred by radiation, and a coefficient of 2.20 may be used with sufficient accuracy for each of these surfaces, although in very precise work a correction should be made to allow for the fact that the area of a pitched roof over an unheated attic is greater than the area of the ceiling, and hence, the amount of heat absorbed by radiation by each square foot of roof surface is less than is given off by radiation by each square foot of ceiling surface. If the unheated attic space between the roof and ceiling has no dormers, windows or vertical wall surfaces, the combined coefficients may be used for determining the heat loss through the roof construction between the attic and top-floor ceiling, but it should be noted that these coefficients should be multiplied by the roof area and not by the ceiling area. If the unheated attic contains windows, ventilators or vertical wall surfaces, which would tend to reduce temperature in the attic to a temperature approaching or equaling the outside temperature, the roof should be neglected and only the top-floor ceiling construction and the correspond ing ceiling area taken into consideration, using the coefficients given ih Tables 8 or 9. Where there are no dormers, doors, or windows, and when the transmission coefficients of the roof and the ceiling are approximately the same, the value of the attic temperature may be taken as an average between the inside and the outside temperature. . Basements and Untreated Rooms The heat loss through floors into basements and into unheated rooms kept closed may be computed by assuming a temperature for these rooms of 32 F. Additional information on the inside and outside temperatures to be used in heat loss calculations is given in Chapter 7. REFERENCES A.S.H.V.E. research paper entitled Wind Velocity Gradients Near a Surface and Their Effect oh Film Conductance, by F. C. Houghten and Paul McDermott (A.S.H.V.E. Transactions, Vol. 37, 1931). A.S.H.V.E. research paper entitled Surface Conductances as Affected by Air Velocity, Temperature and Character of Surface, by F. B. Rowley, A. B. Algren and J. L. Blackshaw (A.S.H.V.E. Transactions, Vol. 36, 1930). .. A.S.H.V.E;:research paper entitled Effects of Air Velocities on Surface Coefficients, by F. B. Rowley.. A. B. Algren and J. L. Blackshaw (A.S.H.V.E. Transactions, Vol. 36, 1930). . A.S.H.V.E. research paper entitled Conductivity of Concrete, by F. C, Houghten and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 37, 1931). ' . A.S.H.V.E. research paper entitled Surface Coefficients as Affected by Direction of Wind, by F. B. Rowley and W. A. Eckiey (A.S.H.V.E. ,Transactions, Vol. 37, 1931). A.S.H.V.E. research paper entitled Thermal Resistance of Air Spaces, by F. B. Rowley and A. B. Algren (A.S.H.V.E. Transactions, Vol. 35, 1929). . .. - . 128 g___ Heat Transmission Coefficients and Tables Chapter A.S.H.V.E. research paper entitled The Heat Conductivity of Wood at Climatic Temperature Dif ferences. by F. B- Rowley (A.S.H.V.E. Journal Section, Heating, Piling and Air ConditiobniyngF, -JuBn-e^1933) 8y F- B- ROWley and A- B- "* University of Min- V.EI.nTsRuAlaNtiSnAgCETIfOfeNcSt,oVf Soul.c3ce7s, s1iv9e3A1)i.r Spaces Bounded by Bright Meta. llic Surfaces; by L. W. Schad '(A aS H - Importance of Radiation in Heat Transfer through Air Spaces, by E. R. Queer (A.S.H.V.E. Trans actions, Vol. 38, 1932). '- Properties of Metal Foil as an Insulating Material, by J. L. Gregg (Refrigerating Engineering May 1932) Thermal Insulation with Aluminum Foil, by R. B. Mason (Industrial and Engineering CkLiistr* MarHceha, t1in9g3.3)V- entilating and Air Conditioning, by Harding and Willard. Revised Edition. 1932. ComTHhmoueitsrtmeeeaInlosInnusWlautoliaootndio. nUIttosilfizEBacutoiionldoninm, giUesns. iTtaeendcdhSAntaipctepasllicPGaaotvpioeernrn,mNbeoyn. t1RP1urs(inAsteminllegEricO. afBfnicaeAc,krc1sh9tri3toe1mc) t,((RMeao5yo0,'r1t 9o3`f4t).h.i,e. N,,rat.iona,l Jut. '-'-A Rtiildines and Structures, by E. A. All University of Toronto, 1934. PROBLEMS IN PRACTICE . What is the coefficient V and how is it applied? rhe coefficient V is the heat loss through walls, ceilings, and floors and the value depends ...on Hip construction and material, expressed in Btu per hour per square foot per degree * ` '' * ` ' ' nn -1--*------ ----- I Um^t- 2 t What is the conductivity of face brick? 9.20 (Table 2). . 3 What is the conductance of wood shingles? . 1.28 (Table 2). . 4 What is the over-all coefficient of transmission XJ for a solid brick wall 12-in. thick with plaster on wood lath, furred? 0.24 (Table 3, Wall 2C). ` 5 Find the value of U for a 6-in. concrete wall with plaster on metal lath attached to 2-in. furring strips with flanged blanket insulation. 0.23 (Table 3, Wall 12L). 6 Find the value of U tor a wood siding wall with an interior finish of %-in. plaster on metal lath; sheathing thickness, in. 0.26 (Table 5, Wall 41B). . 7 What value of V should be used for a brick veneer wall with J-in. rigid insulation sheathing finished on the interior with plaster on J-in. rigid insu lation? . .; 0.19 (Table 5, Wall 51D). 8 t What value of V should be used in computing the heat loss from an attic through a floor of yellow pine on joists with a ceiling of metal lath and plaster. 0.30 (Table 8, Floor 2B). 9 0 What is the over-all heat transfer coefficient for a 6-in. concrete floor witu no insulation and' with yellow pine flooring on sleepers resting on concrete. 0.33 (Table 10, Floor 2B). " 129 American Society of Heating and Ventilating Engineers Guide, 1936 10 What is the coefficient U for a built-up flat roof of 4-in. concrete with a A metal lath and plaster ceiling insulated with 1-in. cork board? ^ 0.17 (Table 11, Roof 3N). ' 11 A solid 12-in. common brick wall is finished on the inside with J^.jD i insulation plaster base, and J^-in. plaster; the plaster base is furred 1 in. froin i the brick; k for insulating material V. . 0.34. Calculate the over-all coefficient t ft fi = 1.65;/o = 6.00; k for brick = 5.00; o for 1-in. air space = 1.1 i' Ov,,-,ll hl resistance - R - + |f + [J + V + v-jc-vm TMi .| 12 A wall is built with two layers of 2'6-in. insulating material spaced 1 in. ? apart; the air space is lined on one side with bright aluminum foil; mean temperature is 40 F; still air on both sides of wall; fc for insulating materia] is 0.34. Calculate the value of U. ; ' fi - 1.65;/0 = 1.65; a = 0.46 _L _gj. | _1 , 0-5 , 1 1.65 ^ 0.34 ^ 0.46 + 0.34 + 1.65 6.327 i; 1 ' [/ = --= 0:158 It T; 13 What is the inside surface temperature of a 6-in. solid concrete wall? v Inside air, 70 F; outside air, --20 F with 15 mph wind. . t, The temperature drop from point to point through a wall is directly proportional to the ) heat resistance. fi = 1.65; k for concrete = 12;/Q = 6.0 Over-all resistance R = + "^ + =1.27 ., . .1 Temperature drop, inside air to surface = 1.65 Temperature drop, air to air 1.27 Temperature drop, inside air to surface = - _ 90 .= 43 . . 1.27 X 1.65 70 -- 43 = 27 F, inside surface temperature of wall. f-' )j I*: } 14 How many inches of insulating material having a conductivity of 0.30 would he required, for the wall of Question 3, to raise the inside surface tem perature to 60 F? \Temperature drop, air to inside surface = 10 F; temperature drop, inside surface to out side air = 80 F. Therefore, the heat resistance from inside wall surface to outside air must be eight times that from inside air to inside wall surface,'or 8 X , 4 = 4.85. The . resistance for. added material is, therefore, . 1.65 - i. 485-(1 + ) =419 4.19 X 0.30 = 1.25 in. of insulation. 130 Chapter 6 air leakage Nature of Air Infiltration, Air Leakage Through Walls, Window Leakage, Wind Telocity to be Selected, Crack usedfor Computa tions Multi-Story Buildings, Heat Equivalent of Air Entering ' by Infiltration AIR leakage losses are those resulting from the displacement of heated air in a building by unheated outside air, the interchange taking place through various apertures in the building, such as cracks around doors and windows, fireplaces and chimneys. This leakage of air must be considered in heating and cooling calculations. (See Chapters 7 and 8.) THE NATURE OF AIR FILTRATION The natural movement of air through building construction is due to two causes. One is the pressure exerted by the wind; the other is the difference in density of outside and inside air because of differences in temperature. 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 resis tance 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 experienced 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 general case. Tests on mechanically ventilated classrooms of average construction have shown that air infiltration acts quite independently of the planned air supply. Accor dingly, the heating or cooling load owing to air infiltration from natural causes should be considered in addition to the ventilating load. The air exchange owing to temperature difference, inside to outside, is not appreciable in low buildings. In tall, single story buildings with openings near the ground level and near the ceiling, this loss must .be considered. Also in multi-storied buildings it. is a large item unless the sealing between various floors and rooms is quite perfect. 'This tempera ture effect is a chimney action, causing air to enter through openings at lower levels and to leave at higher levels. - 131 of and 1936American Society Heating Ventilating Engineers Guide, A complete study of all of the factors involved in air movement through building constructions would be very complex. Some of the complicating factors are: the variations in wind velocity and direction; the exposure of the building with respect to air leakage openings and with respect to adjoining buildings; the variations in outside temperatures as influencing the chimney effect; the relative area and resistance of openings on the windward and leeward sides and on the lower floors and on the upper floors; the influence of a planned air supply and the related outlet ventsand the variation from the average of individual building units. A study of infiltration points to the need for care in the obtaining of good building construction, or unnecessarily large heat losses will result. AIR LEAKAGE THROUGH WALLS Table 1 gives data on infiltration through brick and frame walls. The brick walls listed in this table are walls which show poor workmanship and which are constructed of porous brick and lime mortar. For good workmanship, the leakage through hard brick walls with cement-lime mortar does not exceed one-third the values given. These tests indicate that plastering reduces the leakage by about 96 per cent; a heavy coat of cold water paint, 50 per cent; and 3 coats of oil paint carefully applied, 28 per cent. The infiltration through walls ranges from 6 to 25 per cent 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 per cent or a practically negligible quantity, which indicates the importance of good workmanship in proper sealing at the baseboard. It will be noted from Table 1, that the in filtration through properly plastered walls can be neglected. ' Table 1. Infiltration through Walls Expressed in cubic feet per square foot per hour* 1 Worn Veloott, Miles per Hour 5 8Min. Brick Wall------- {plastered.". \- 1.75 0.017 10 4.20 0.037 is , 20 25 30 7.85 12.2 18.6 22.9 0.066 0.107 0.161. 0.236 13 in. Brick Wall--------- 1.44 3.92 7.48 1116 16.3 21.2 0.005 0.013 0.025 0.043 0.067 Otf97 Frame Wall, with lath and plaster*1 0.03 0.07 0.13 0.18 0.23 ! 0.26 The values given in this table are 20 per cent less than test values to allow for building up of pressure in rooms and are based on test data reported in the papers listed p. 140. \ bWall construction: Bevel siding painted or cedar shingles, sheathing, building paper, wood lath and 3 coats gypsum plaster. - . . . 132 Chapter 6--Air Leakage Fig. 1. Infiltration through Various Types of Shingle Construction The value of building paper when applied between sheathing and shingles is indicated by Fig. 1, which represents the effect on outside construction 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 difficult to secure and maintain the full effectiveness of the plaster but also it is highly desirable to have two points of high resistance to air flow with an air space between them. o go 40 go eo too *eo mo too /go goo ego ltmLTf**rroK m C-F.H. Pen Sp. Ft. or Wall Fig. 2. Infiltration through Single Surface Walls Used in Farm and Other Shelter Buildings American Society of Heating and Ventilating Engineers Guide, 1936 The amount of infiltration that may be expected through simple walls used in farm and other shelter buildings, is shown in Fig. 2. The infil tration indicated in Figs. 1 and 2 is that determined in the laboratory and should be multiplied by the factor 0.80 to give proper working values. WINDOW LEAKAGE 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 as illustrated in Fig. 3. 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. Values of leakage shown in Table 2 for the average double-hung wood window were determined by setting the average measured crack and clearance found in a field survey of a large number of windows on nine windows tested in the laboratory. In addition, the table gives figures for a poorly fitted window. All of the figures for double-hung wood windows are for the unlocked condition. Just how a window is closed, or fits when it is closed, has considerable influence on the leakage. The leakage will be high if the sash are short, if the meeting rail members are warped, or if the frame and sash are not fitted squarely to each other. It is possible to .have a window with approximately the average crack and clearance that will have a leakage at least double that of the figures shown. Values for the average doublehung wood window in Table 2 are considered to be easily obtainable figures provided the workmanship oh the window is good. Should it be known that the windows under consideration are poorly fitted, the larger leakage values should be used. Locking a window generally decreases its leakage, but in some cases may push the meeting rail members apart and increase the leakage. On windows with large clearances, locking will usually reduce the leakage. Wood casement windows may be assumed to have the same unit leakage as for the average double-hung wood window when, properly fitted. Locking, a normal operation in the closing of this type of window, maintains the crack at a low value. For metal pivoted sash, the length of ..crack is the total perimeter of the movable or ventilating sections. Frame leakage on steel windows may be neglected when they are properly grouted with cement mortar into brick work or concrete. When they are not properly sealed, the linear feet of sash section in contact with steel work at mullions should be figured at 25 per cent of the values for industrial pivoted windows as given in Table 2. Leakage values for storm sash are given in Figs. 4 and 5. When storm sash are applied to well fitted windows, very little reduction in infiltration is secured, but the application of the sash does give an air space which reduces the heat transmission and helps prevent the frosting of the windows. When storm sash are applied to poorly fitted windows, a. reduction in leakage of 50 per cent may be secured. ' 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 Chapter 6--Air Leakage Table 2. Infiltration Through Windows Expressed in Cubic Feet per Foot of Crock per Houm Ttt* or Window PeifAPTtB . Worn Velocity, Mn.es psa Houn 5 10 15 20 25 30 ------------ : A/ouod frame in masonry wall--not calked** 3.3 8.2 14.0 20.2 27.2 34.6 Around frame in masonry wall--oalkedb------ 0.5 1.5 2.6 3.8 4.8 5.8 Around frame in wood frame construction**-- 2.2 6.2 10.8 16.6 23.0 30.3 Double-Hung Total for average window, non-weather- Wood Sash stripped. 56-*n- crack and 56-in. clearance. Includes wood frame leakage*----------------- 6.6 21.4 39.3 (Unlocked) Ditto, weatbcrstrippedd---------------------------- 4.3 15.5 23.6 59.3 35.5 80.0 103.7 48.6 63.4 TnfnI for noorlv fitted window, non-weather- stripped, 56-m. crack and 56-in. clearance. Includes wood frame leakage*----------------- Ditto, weatherstrippedd----------------------------- 26.9 69.0 110.5 5.9 18.9 34.1 153.9 51.4 199.2 70.5 249.4 91.5 Double-Hung Non-weatherstripped, locked-- ------ -- 20 Non-weatherstripped, unlocked.. ,,. . -- 20 45 47 70 74 96 125 154 104 137 170 Windows! Weatherstripped, unlocked--..................-- 6 19 32 46 60 76 OcL&ll Windows1* Industrial pivoteds. 56-in. crack--------------- 52 108 Architectural projected, 56*4* crack**-------- 15 36 Architectural projected, 56-in. crack**--------- 20 52 Residential casement, 56-in. crack* Residential casement, 56-in. crack* __ 6 18 . 14 32 Heavy casement section, projected, 56-in. 3 10 Heavy casement section, projected 56-in. cracki----- ---------------------- ---------------------- 8 24 176 62 88 33 52 18 38 244 86 116 47 76 26 54 . 304 112 152 60 100 36 72 372 139 182 74 128 48 92 Hollow Metal, vertically pivoted window!. 30 88 145 186 221 242 The values given in this table are 20 per cent less than test values to allow for building up of pressure in rooms, and are based on test data reported in the papers listed at the end of this chapter. - bTbe values given for frame leakage are per foot of sash perimeter as determined for double-hung wood windows. Some of the frame leakage in masonry walls originates in the brick wall itself and cannot be prevented by calking. For the additional reason that calking is not done perfectly and deteriorates with' time, it is considered advisable to choose the masonry frame leakage values for calked frames as the average determined.by the calked and not-calked tests. - ' oThe fit of the average double-hung wood window was determined as J6-ln. crack and 56-in. clearance by measurements on approximately 600 windows under heating season conditions. *The values given are the totals for the window opening per foot of sash perimeter and include frame leakage and so-called elsewhere leakage. The frame leakage values included are for wood frame construction but apply as well to masonry construction assuming a 60 per cent efficiency of frame calking. . A 56-in. crack and clearance represents a poorly fitted window, much poorer than average. Windows tested in place in building. (Industrial pivoted window generally used in industrial buildings. Ventilators horizontally pivoted at center or slightly above, lower part swinging out. ' ^Architectural projected made of same sections as industrial pivoted except that outside framing member is heavier, and 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 best practice of manufacture and installation, 56 in. crack considered to represent average practice. Of aame design and section shapes as so-called heavy section casement but of lighter weight. 16 >n- crack is obtainable in the best practice of manufacture and installation, 56 in. crack considered to represent average . practice. , JMade of heavy sections. Ventilators swing in or out and stay set at any degree of opening. 56 in* crack is obtainable in the best practice of manufacture and installation,'56 in* crack considered to represent average practice. With reasonable care in installation, leakage at contacts where windows are attached to steel fraxne- *nric and at mullions is negligible. With 56-in. crack, representing poor installation, leakage at contact with steel framework is about one-third, and at mullions about one-sixtb of that given for industrial pivoted windows in the table. . 135 of andAmerican Society Heating Ventilating Engineers Guide, 1936 be used. If weatherstripped, the values may be reduced one-half. A single door which is frequently opened, such as might be found 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 windiest weather. CHOOSING WIN D VELOCITY Although all authorities do not agree upon the value of the wind veloc- ity that should be chosen for any given locality, it is common engineering practice to use the average wind velocity during the three coldest months of the year. Until this point is definitely established the practice of using average values will be followed. Average wind velocities for the months of December, January and February for various cities in the United States and Canada are given in Table 2, Chapter 7. J% | 1 f f I H 2 Chapter 6--Air Leakage 12 KU | 1.0 / 0t c 4 1 B k Lr L -j 1L 1 A 03 S OF, $07 j1 7 L t1 t t1 r L j 1 11t t L A-V 1 I x Q6 V k04 Q Q3 I" 11 7 11 t 4( 1f 4 ./ a 1 Ll f It /k 7/ t ft Y' wwITfr rmjK HJgN OUTTON3 u- OAHE AS C WITH WOOL WvmcR-Sntp Applied jj 09 0 50 JOO 150 200 250 500 Infiltration CF.HPer rpcrr Or Crack 50.03 45.69 ift % 4089 (jjj 3540 X 2630 | 2042 1 0 F,g. 4. Infiltration through Sash Perimeter of Window with and without '. Storm Sash--^U-in. Crack and H2-IN. Clearance Fig. 3. Diagram Illustrating Crack and Clearance In considering both the transmission and infiltration losses, the more exact procedure would be to select the outside temperature and the wind velocity corresponding thereto, based on Weather Bureau records, which would result in the maximum heat demand. . Since the proportion of transmission and infiltration losses varies with the construction and is different for every building, the proper combination of temperature and wind velocity to be selected would be different for every type of building, even in the same locality. Furthermore, such a procedure would neces &a sitate a laborious cut-and-try process in every case in order to determine the worst combination of conditions for the building under consideration. It would also be necessary to consider heat lag due to heat capacity in the case of heavy masonry walls, and other factors, to arrive at the most 1 accurate solution of the problem. Although heat capacity should be con sidered wherever possible, it is seldom possible to accurately determine the worst combination of outside temperature and wind velocity for"a given building and locality. The usual procedure, as already explained, is to select an outside temperature based on the lowest on record and the. average wind velocity during the months of December, January and February. , . .. V The direction of prevailing winds may usually be included within an angle of about 90 deg. The windows that are to be figured for prevailing 136 and non-prevailing winds will ordinarily each occupy about one-half the perimeter of the structure, the proportion varying to a considerable extent with the plan of the structure. (See discussion of wind movement in Chapter 4.) . rlG.. Infiltration through Sash Perimeter of Window with and without Storm Sash--fi-m. Crack and J^-in. Clearance 137 American Society of Heating and' Ventilating Engineers Guide, 1936 CRACK USED FOR COMPUTATIONS In no case should the amount of crack used for computation be less than half of the total crack in the outside walls of the room. Thus, 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. For a building having no partitions, whatever wind enters through the cracks on the windward side must leave through the cracks on the leeward side.. Therefore, take one-half the total crack for com puting each side and eiid of the building. ; The amount of air leakage is sometimes roughly estimated by assuming a certain number of air changes per hour for each room, the number of changes assumed being dependent upon the type, use and location of the room, as indicated in Table 3. This method may be used to advantage as a check on the calculations made in the more exact manner. ; . * i < r Table 3. Air Changes Taking Place under Average Conditions Exclusive of Air'Provided for Ventilation ' Kind or Room ob Building Number or Air Charges Taking Place per Hour ' Rooms, 1 side exposed..... --------------- .............. ...........................:...... Clothing Stores_____ ______________ -................................................ ,i. IH 2 2 Xto H 2 to 3 2 1 to 2 1 to 2 2. 2 to 3 i Hto3 .\ > MULTI-STORY BUILDINGS '| -` '. > In tall buildings, infiltration may be considerably influenced by tem- | perature difference or chimney effect which will operate to produce 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 s isolation of floors preventing free upward mbvement, so that wind and | temperature difference may seldom cooperate to the fullest extent, i Making the rough assumption that the neutral zone is located at mid- a : height of a building, and that the temperature difference is 70 F', the $ following formulae may be used to determine an equivalent wind velocity ^ j 1X8 Chapter 6--Air Leakage , :n connection with Tables 1 and 2 that will allow for both wind velocityand temperature difference: ' Me = y/M* - 1.75 a (1) Me = + 1.75 b (2) where Me = equivalent wind velocity to be used in conjunction with Tables 1 and 2. M = wind velocity upon which infiltration would be determined if tem perature difference were disregarded. a = distance of windows under consideration from mid-height of building if above mid-height. b = distance if below mid-height. 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, although probably no greater wind velocities should be figured at such extremely high levels. 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 re mainder. 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 enclosures should be tight and solid doors should be used. If the sealing of the vertical openings is made effective, no allowance need be made for the chimney effect. Instead, the greater wind move ment at the high altitudes makes it advisable to install additional heating surface on the upper floors above the level of neighboring buildings, this additional surface being increased as the height is increased. One arbitrary 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 tlje windward side and on windy days, and hence automatic temperature control is especially desirable with such installations. . Heating Surface for Stair-Wells In stair-wells that are open through many floor levels although closed off from the remainder of eaich 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 even to the point of omitting all heating surface on the top several floor 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. of and 1936American Society Heating Ventilating Engineers Guide, HEAT EQUIVALENT OF AIR ENTERING BY INFILTRATION . The heat required to warm cold, outside air, which enters a room by infiltration, to the temperature of the room is given by the following equation: Hi = 0.24 Qd{t -- t0) (3) where Hi = Btu per hour required for heating air leaking into building from outside temperature t0 to inside temperature t. Q = cubic feet of air entering per hour at inside temperature l. d -- density (pounds per cubic foot) of air at inside temperature t. t = inside temperature at the proper level. ' . to = outside air temperature for which heating system is designed. 0.24 = specific heat of air. It is sufficiently accurate to take d = 0.075 lb, in which case the equa tion reduces to : Hi = 0.018 Q (t -- l0) (4) While a heating reserve must be provided to warm inleaking air on the windward side of a building, this does not necessarily mean that the heating plant must be provided with a reserve capacity, since the inleaking air, warmed at once by adequate heating surface in exposed rooms, will move transversely and upwardly through the building, thus relieving other radiators of a part of their load. The actual loss of heat of a building caused by infiltration is not to be confused with the necessity for pro viding additional heating capacity for a given space. Infiltration is a disturbing factor in the heating of a building, and its maximum effect (maximum in the sense of an average of wind velocity peaks during the heating season above some reasonably chosen minimum) must t}e met by a properly distributed reserve of heating capacity, which reserve, how ever, is not in use at all places at the same time, nor in any one place at all times. REFERENCES 1 I j Air Leakage, by Houghten and Schrader (A.S.H.V.E. Transactions, Vol. 30, 1924). Air Infiltration through Various Types of Brick Wall Construction, by Larson, Nelson and Braatz (A.S.H.V.E. Transactions, Vol. 35, 1929). "\ ' Infiltration through Plastered and Unplastered Brick Walls, by F. C. Houghten and Margaret Ingela (A.S.H.V.E. Transactions, Vol. 33, 1927). .. Air Leakage around Window Openings, by C. C. Schrader (A.SlH.V.E. Transactions, Vol. 30, 1924). Effect of Frame Calking and Storm Sash on Infiltration around'and through Windows, by Richtmann and Braatz (A.S.H.V.E. Transactions, Vol. 34, 1928). . Air Leakage on Metal Windows in a Modern Office Building, by Houghten and O'Connell (A.S.H.V.E. Transactions, Vol. 34, 1928). '. The Weathertightness of Rolled Section Steel Windows, by Emswiler and Randall (A.S.H.V.E. Trans actions, Vol. 34, 1928). . - Air Leakage through a Pivoted Metal Window, by Houghten and O'Connell (A.S.H.V.E. Transactions, Vol. 34, 1928). . . Pressure Difference across Windows in Relation to Wind Velocity, by Emswiler and Randall (A.S.H.V.E. Transactions, Vol. 36, 1930). . . Air Infiltration Through Various Types of Wood Frame Construction, by Larson, Nelson and Braatz (A.S.H.V.E. Transactions, Voli 36, 1930). , .. Neutral Zone in Ventilating, by J. E. Emswiler (A.S.H.V.E. Transactions, Vol. 32,1926).. . Air Infiltration Through Double-Hung Wood Windows, by Larson, Nelson and kubasta (A.S.H.V.E.' Transactions, Vol. 37, 1931). I i j 140 3 Chapter 6--Air Leakage Tall Buildings, by H. L. Ait {Healing. Piping and Air Conditioning, May. 1932). Flue Action in , Framed Windows, by D. O. Rusk, V. H. Cherry and L. Boelter {Heating, Air InfiltraOonThrougt.^ 1932). piping and Atr Investigation o Outlets in Class Room Ventilation, by Larson, Nelson, and Kubasta (A.S.H.V.E. 1932). Transactions. ' Influence of StacK t^e Heat Loss in Tall Buildings, by Axel Marin (A.S.H.V.E. Transactions, Vol. 40, 1934). M Building and Their Effect on Heat Loss, by F. C. Houghten, J. L. Blackshaw, and cS^GulbSS (aSh.V.E. Transactions. Vol. 40, 1934). . PROBLEMS IN PRACTICE -p- ;s jt important in exterior walls of air space construction to place a wind Stop in the outer surface? n 'he the heating season, air within the space is at a higher temperature than outdoor 'If cracks are present in the outer surface, a chimney action takes place which causes ^continuous change of air in the space. This causes a greater heat loss through the ? c wa[j suriace for two reasons; (1) the temperature difference becomes greater and f2) the surface coefficient on the air space side is increased because of the higher air velocity Another undesirable condition resulting from this leakage is a lowered tem- oerature of the inside surface. The increased radiation from occupants to walls caused by this condition must be offset by higher air temperatures. The wind stop in the outer wall surface is therefore important because; a. It reduces the loss of heat through the wall. . b. It helps to maintain a high inner wall surface temperature. 2 Why is it essential to consider this in heating calculations? The inflowing air displaces inside heated air and must be heated up to the internal temperature. 3 Where is it necessary to consider infiltration created by temperature difference? In tall, single-story buildings and in multi-story buildings where the floors are not adequately isolated. 4 Why is the infiltration in a building less than that determined in laboratory tests? In laboratory tests, the indicated wind velocity is measured by the difference in pressure on the two sides of a single wall, window, or object tested. In a building, an internal back pressure is built up between its walls to a point where outflow on the lee side is equal to inflow on the windward side and this back pressure reduces the actual inflow below that determined in the laboratory for a comparable wind. . 5 Is heat loss by infiltration through walls of importance? Only in the case of simple walls or poorly constructed compound walls. 6 What measurements are required to calculate the heat loss through double- hung wood windows? ` Sash crack (equal to the sash perimeter plus the meeting rail) and frame crack (equal to the frame perimeter). ' ~ What is the basis for selecting the wind velocity and outside temperature to be used in making infiltration calculations? ureau records. The wind velocity taken is the average during the three coldest months and the temperature used is the lowest on record for the given locality. 141 of andAmerican Society Heating Ventilating Engineers Guide, 1935 8 How does- the temperature difference influence the heat loss in building? The chimney effect caused by the temperature difference operates to produce a head that will add to the effect of the wind at lower levels and subtract from it at higher levels 9 For a wind velocity of 15 mph and a building 180 ft high, calculate the effective wind velocity at the ground floor and at a height of 150 ft. a. At the ground floor the effective wind velocity would be Me = -v/15* + 1.75 X 90 = 19.6 mph b. At a floor 150 ft above the ground . , Me = V151 - 175 X 60 = 11.0 mph ! 10 9 A room contains three 2 ft-8 in. by 5 ft-6 in. plain double-hung wood win. dows with. crack and %4-in. clearance. Assume a wind velocity 0f 20 mph and a temperature difference of 75 F. Neglecting chimney effect, what is the maximum heat loss due to infiltration? '. ' From Table 2, heat loss per foot of crack per degree temperature difference is 1.067 Btn per hour. Length of crack for the three windows is 57 ft. The maximum heat loss, due to infiltration, is equal to 1.067 X 57 X 75 or 4561 Btu per hour. 11 Find the infiltration through a wall with 16-in. shingles on 1 in. by 4 in. boards with 20 mph wind velocity. Give the pressure drop through the wall. Referring to Curve 3C, Fig. 1, the value on the horizontal scale corresponding to 20 mph is approximately 102 cfh per square foot of wall. The pressure drop through the wall is 0.193 in. of water (see left hand vertical scale). 12 What will be the infiltration through air-dried end and side-matched sheathing for 15 mph wind velocity? - Referring to Curve 10C, Fig. 2, the value on the horizontal scale corresponding to 15 mph is 50 cfh per square foot of wall. " 13 From Table 2, find the infiltration (cubic feet per hour per foot of crack) for an average double-hung window, not weather stripped, with a 20 mph wind velocity. 59.3 cu ft per foot of crack per hour. - 14 Using the value found in Question 11, what will be the heat requirement in a building with a total crack (all windows and doors) of 180 ft if the wind velocity is 15 mph, the outside temperature is 0 F, and the inside temperature is 70 F? Using one half of the total crack, the volume of air is: 90 X 59.3, = 5337 cu ft H = 0.018 X 5337 X (70 - 0) = 6724,6 Btu. (See Equation 4.) 142 Chapter 7 HEATING TOAD Factors Governing Heat Demand, Procedure, Temperatures, Wind Movement, Heat Sources Other Than Heating Plant, Example, Condensation TO design any system of heating, the maximum probable heat demand must be accurately estimated in order that the apparatus installed shall be capable of maintaining the desired temperature at all times. The factors which govern this maximum heat demand--most of which are if f>vr*r in pnnilihrium--include the following: 1. Outside temperature. 2. Rain or snow. 3. Sunshine or cloudiness. 4. Wind velocity. 5. Heat transmission of exposed parts of building. 6. Infiltration of air through cracks, crevices and open doors and windows. 7. Heat capacity of materials. 8. Rate of absorption of solar radiation by exposed materials. 9. Inside temperatures. 10. Stratification of air. 11. Type of heating system. 12. Ventilation requirements. 13. Period and nature of occupancy. . lj. Temperature regulation. ' . Outside Conditions (The Weather) Building Construction Inside Conditions The inside conditions vary from time to time, the physical properties of the building construction may change with age, and the outside conditions are changing constantly. Just what the worst combination of all of these variable factors is likely to be in any particular case is therefore con jectural. Because of the nature of the problem, extreme precision in estimating heat losses at any time, while desirable, is hard of-attainment. The procedure to be followed in determining the heat loss from any building can be divided into seven consecutive steps, as follows: . 1. Determine on the inside air temperature, at the breathing line or the 30-in. line, which is to be maintained in the building during the coldest weather. (See Table 1.) 2. Determine on an outside air temperature for design purposes, based on the minimum temperatures recorded in the locality in question, which will provide for all but the most severe weather conditions. Such conditions as may exist for only a few. consecu tive hours are readily taken care of by the heat capacity of the building itself. (See Table 2.) 143 of andAmerican Society Heating Ventilating Engineers Guide, 1936 3. Select or compute the heat transmission coefficients for outside walls and glass- also for inside walls, floors, or top-floor ceilings, if these are next to unheated space- include roof if next to heated space. (See Chapter 5.) ' 4. Measure up net 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. I 5. Compute the heat transmission losses for each kind .of wall, glass, floor, ceilimr and roof in the building by multiplying the heat transmission coefficient in each ca4 4i by the area of the surface in square feet and the temperature difference between the inside and outside air. (See Items 1 and 2.) 6. Select unit values and compute the heat equivalent of the infiltration of cold air taking place around outside doors and windows. These unit values depend on the kind or width of crack and wind velocity, and when multiplied by the length of crack and the temperature difference between the inside and outside air, the result expresses the heat required to warm up the cold air leaking into the building per hour. (See Chapter 6.) 7. The sum of the heat losses by transmission (Item 5) through the-outside wall and glass, as well as through any cold floors, ceilings or roof, plus the heat equivalent (Item6) of the cold air entering by infiltration represents the total heat loss equivalent for any building. . Item 7 represents the heat losses after the building is heated and under stable operating conditions in coldest weather.. Additional heat is required for raising the temperature of the air, the building materials and the material contents of the building to the specified standard inside temperature.- The rate at which this additional heat is required depends upon the heat capacity of. the structure and its material contents and upon the time in which these are to be heated. ' This additional heat may be figured and allowed for as conditions re- Table 1. Winter Inside Dry-Bulb Temperatures Usually Specified3 Ttpe of Building Deg Fahb Type of Building . Deg Fahb Schools Toilets and baths.......................... Wardrobe and locker rooms- . Hospitals-- Kitchens and laundries................ Toilets.________ :___ :......... .............. Theaters-- 70-72 ' 68-72 68-72 68-72 55-65 68 70 65-68 Hotels-- 66 70 65-70. 70 60-65 66 75 65-68 Toilets and service rooms._______ 68 70-72 70-80 70-95 68 66 68 70-80 Homes - Stcirf.s PiTRT.ir mTTT.nTNr,<; Warm atr ratws Stf.am. raths Factories and machine shops____ Foundries and boiler shops......... : Paint shops............ .................................. 70-72 65-68 68-72 120 110 60-65 50-60 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 3. ' 144 Chapter 7--Heating Load hut inasmuch as the heating system proportioned for taking care ' heat losses will usually have a capacity about 100 per cent greater f the n ^ reqUjred for average winter weather, and inasmuch as most n'iH' es may either be continuously heated or have more time allowed building during the few minimum temperature days, no allowance is mack except in the size of boilers or furnaces. INSIDE TEMPERATURES The inside air temperature which must be maintained within a building ' d which should always, be stated in the heating specifications is undera" . t0 ke ^e dry-bulb temperature at the breathing line, 5 ft above the floor or the 30-in. line, and not less than 3 ft from the outside walls. Inside air temperatures, usually specified, vary in accordance with the use to which the building is to be put and Table 1 presents values which con form with good practice. The proper dry-bulb temperature to be maintained depends upon the relative humidity and air motion, as explained in Chapter 3. In other words, a person may feel warm or cool at the same dry-bulb temperature, depending on the relative humidity and air motion. The optimum winter effective temperature for sedentary persons, as determined at the A.S.H. V.E. Research Laboratory, is 66 deg.1 According to Fig. 5, Chapter 3, for so-called still air conditions, a relative humidity of approximately 50 per cent is required to produce an effective temperature of 66 deg when the dry-bulb temperature is 70 F. However, even where provision is made for artificial humidification, the relative humidity is seldom maintained higher than 40 per cent during the extremely cold weather, and where no provision is made for humidifica tion, the relative humidity may be 20 per: cent or less. Consequently, in using the figures given in Table 1, consideration should be given to whether provision is to be made for humidification, and if so, the actual relative humidity to be maintained. Temperature at Proper Level: 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 1 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. In the case of heated spaces adjacent to unheated spaces, It will usually be sufficient to assume the temperature in such spaces as the mean between the temperature of the inside heated spaces and the outside air tempera ture, excepting where the combined heat transmission coefficient of the roof and ceiling can be used, in which case the usual inside and outside temperatures should be applied. (See discussion regarding the use of combined coefficients of pitched roofs, unheated attics and top-floor ceilings Chapter 5.) of andAmerican Society Heating Ventilating Engineers Guide, 1935 High Ceilings: Research data concerning stratification of air in build, i ings are lacking, but in general it may be said that where the increase in -1 temperature is due to the natural tendency of the warmer or less dense i air to rise, as where a direct radiation system is installed, the temperature of the air at the ceiling increases with the ceiling height. The relation ' however, is not a straight-line function, as the amount of increase per foot - of height apparently decreases as the height of the ceiling increases, ac cording to present available information2. . ;> Where ceiling heights are under 20 ft, it is common engineering-practice to consider that the Fahrenheit temperature increases 2 per cent for each foot of height above the breathing line. This rule, sufficiently accurate for most cases, will give the probable air temperature at any given level '! for a room heated by direct radiation. Thus, the probable temperature -j in a room at a point three feet above the breathing line, if the breathing line temperature is 70 F, will be i (1.00 + 3 X .02) 70 = 74.2 F. : With certain types of heating and ventilating systems, which tend to oppose the natural tendency of warm air to rise, the temperature differ- , ential between floor and ceiling can be greatly reduced. These include unit heaters, fan-furnace heaters, and the various types of mechanical ventilating systems. The amount of reduction is problematical in certain : instances, as it depends upon many factors such as location of heaters, . air temperature, and direction and velocity of air discharge. In some ; cases it has been possible to reduce the temperature between the floor and ceiling by a few degrees, whereas, in other cases, the temperature at the ceiling has actually been increased because of improper design, instal- j lation or operation of equipment. So much depends upon the factors enumerated that it is not advisable to allow less than 1 per cent per foot ; (and usually more) above the breathing line in arriving at the air tem- ' perature at any given level for any of these types of heating and ventilating systems, unless the manufacturers are willing to guarantee that the par- < ticular type of equipment under consideration will maintain a smaller ;; temperature differential for the specific conditions involved. ( Temperature at Floor Level: In determining mean air temperatures l' just above floors which are next to ground or unheated spaces, a tempera- -y ture 5 deg lower than the breathing-line temperature may be used, pro- j; vided the breathing-line temperature is not less than 55 F. ' ). OUTSIDE TEMPERATURES The outside temperature used in computing the heat loss from a build ing is seldom taken as the lowest temperature ever recorded in a given | locality. Such temperatures are usually of short duration and are rarely - repeated in successive years. It is therefore evident that a temperature somewhat higher than the lowest on record may be properly assumed in making the heat-loss computations. . Temperature Gradient Observations in a Large Heated Space, by G. L. Larson, D. W. Nelson-and O. C. Cromer (A.S.H.V.E. Transactions, Vol. 39. 1933). . Tests of Three Heating Systems in an Industrial Type of Building, by G. L. Larson, D. W. Nelson and. r John James (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, November, 1934). -o 146 I' Chapter 7--Heating Load The outside temperature to be assumed in the design of any heating tem is ordinarily not more than 15 deg above the lowest recorded tem^ature as reported by the Weather Bureau during the preceding 10 pej"rs for the locality in which the heating system is to be installed. In the case of massive and well insulated buildings in localities where the minimum does not prevail for more than a'few hours, or where the lowest recorded temperature is extremely -unusual, more than 15 deg above the minimum may be allowed, due primarily to the. fly-wheel effect of the heat capacity of the structure. The outside temperature assumed and used in the design should always be stated in the heating specifications. Table 2 lists the coldest dry-bulb temperatures ever recorded by the Weather Bureau at the places listed. If Weather Bureau reports are not available for the locality in question, then the reports for the station nearest to this locality are to be used, unless some other temperature is specifically stated in the specifications. In computing the average heat transmission losses for the heating season in the United States the average outside temperature from October 1 to May 1 should be used. WIND MOVEMENT The effect of wind on the heating requirements of any building should be given consideration under two heads: 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 movement materially increases the infiltration (inleakage) of cold air through the cracks around doors and windows, and even through the building materials them selves, if such materials are at all porous. Theoretically as a basis for design, the most unfavorable combination of temperature and wind velocity should be chosen. It is entirely possible that a building might require more heat on a windy day with a moderately low outside temperature than on a quiet day with a much lower outside temperature. However, the combination of wind and temperature which is the worst would differ with different buildings, because wind velocity has a greater effect on buildings which have relatively high infiltration losses. It would be possible to work out 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, pending further studies of actual buildings, it is recommended that the average wind movement in any locality during December, January and February be provided for in computing (1) the heat trans mission of a building, and (2) the heat required to take care of the infiltra tion of outside air. . The first condition is readily taken care of, as explained in Chapter 5, by using a surface coefficient f0 for the outside wall surface which is based on the proper wind velocity. In case specific data are lacking for any given locality, it is sufficiently accurate to use an average wind velocity of approximately 15 mph which is the velocity upon which the heat trans mission coefficient tables in Chapter 5 are based. In a similar manner, the heat allowance for. infiltration through cracks 147' of andAmerican Society Heating Ventilating Engineers Guide, 1936 Table 2. Climatic Conditions Compiled from Weather Bureau Records* Col. A ' State Ala Ark Calif-........... DC Fla Ga Til Ind. Col. B City . Kv. Me. Md. Mo. N. H........ . N. J. N. V.' Buffalo............ .......... ..... New York...................... Col. C Average Temp., Oct 1stMay 1st 58.9 53.8 59.5 35.8 50.4 51.6 54.2 58.5 38.9 38.9 38.4 43.4 62.0 51.5 58.5 42.3 35.7 36.4 39.8 40.3 45.1 33.9 32.6 39.8 41.4 45.3 61.6 56.2 31.5 33.8 43.8 38.1 29.6 35.8 28.3 24.3 29.4 56.8 X 40.7 43.6 : 44.3 34.0 , 27.6 37.0 35.4 39.4 37.9 33.3 41.6 35.2 34.8 40.7 Col. D Lowest Tempera* ture Ever Reported Col. E Average Wind Vel ocity Dec., Jan., Feb., Miles per Hour Col. F Direction of Prevail, ing Wind, Dec., Jan Feb. -l 10.4 N -10 8.5 N 12 6.4 E -25 7.8 SW -15 8.1 E -12 8.7 NW 27 7.6 N 28 6.3 NE -29 7.5 S -21 5.3 NW -15 9.7 N -15 7.1 NW 10 9.2 NE --8 12.1 NW 8 9.5 NW -23 5.3 E -28 9.6 SE -23 12.5 W -24 10.1 NW -25 11.5 SW -16 9.8 s -32 7.1 NW -35 11.6 NW -25 8.1 s -.' -26 9.8 NW -20 9.9 SW 7 8.8 N -5 8.9 SE -23 12.0 W -21 9.2 NW -7 7.8 'NW -.18 11.2 W -28 12.4 W -24 12.7 SW -27 11.1 NW -41 12.6 SW -33 11.3 . NW -1 8.3 SE . -24 9.3 NW- -22 11.6 S -29 10,8 ' SE .-49 W - '--57 , - 9.5 SW -29 10.5 - s -35 . 8.5 w -10 10.0 SE -28 . 8.7 NE ' -35 6.6 NW -9 : 15.9' NW -24 8.1 " S -20 17.2 : W -14 17.1 ` NW i s i ,U. S. data from U. S. Weather Bureau. . ;: Canadian data from Meteorological Service of Canada. 148 Table o2. nc,lTimuajri.icr Conditions. C(oCmopnitlienduefdr)om Weather Bureau Records* State or province Col. B City Col. C Average Temp., Oct. 1stMay 1st Col. D Lowest ' Tempera ture Ever Reported Col. E Average Wind Vel ocity Dee., Jan.. Feb., Miles per Hour ' Col. F ' Direction of PrevaU. ing Wind, Dec., Jan., Feb. * N. M............. N. C.............. Wilmington........................ 38.3 50.0 54.2 -13 -2 5 Bismarck............................. 24.6 -45 Devils Lake........................ Ohio............... Columbus.-......................... 20.3 37.2 39.9 -44 -17 -20 Oklahoma City................. 47.9 -17 Baker................................... Portland.............................. 35.2 46.1 -24 -2 Philadelphia.. .................. 42.7 -6 Pittsburgh..... ..................... 41.0 -20 37.2 -17 57.4 7 Columbia............................ 54.0 -2 Huron..--............................. 28.2 -43 Rapid City....... ................. 33.4 -34 47.9 -16 Memphis.:....................... -- 51.1 -9 53.5 -5 Fort Worth........................ 55.2 -8 San Antonio.- ................ . 60.6 4 36.3 -24 Salt Lake City.................. 40.0 -20 Vi- Burlington.......................... 31.5 -29 Va 49.3 ' 2 Lynchburg.......................... 46.8 -7 Richmond. _ .....1.............. 47.0 -3 44.8 3 Spokane............................... 37.7 -30 W Va Parkersburg............. ......... 39.4 42.6 -28 -27 Wis................ 30.0 -36 La Crosse............................ 31.7 -43 Wyn Milwaukee......................... 33.4 30.7 . -25 -41 30.0 -40 23:0 -57 B. c. ....... Victoria. ....................... 43.9 - 1.5 Vancouver......... ................ 42.0 2 17.5 -47 N. B.............. ' 27.0 . --35 N. S.............. 35.0 -12 Ont..............,, 32.6 --27 Ottawa..!........................... 26.5 -34 Port Arthur.................... . 22.4 -37 Toronto...... . .. P. E. I..__.... Charlottetown ...,............. Que............. 32.9 29.0 27.8 . -26.5 -27 --29 . Quebec............. ................ Sask.._....... Prince Albert..................1:. Yukon........... Dawson. * 24.2 15.8 2.1 . -34 -70. -68 . 7.8 NE 8.2 SW 8.5 SW 9.1 NW . 10.6 W 13.0 SW 12.0 SW 12.0 N 6.9 SE 7.5 S 11.0 NW 11.7 W 12.8 NW 10.6 SW 8.1 NE . 10.6 NW 8.2 W 7.8 SW 9.7 S 10.4 NW - 10.4 NW 8.0 NE 8.8 W 6.7 SE 11.8 S 12.5 N 7.1 NW 7.9 SW 11.3 SE 7.1 SW 6.6 W 7.5 SW 10.4 SW 7.3 S 11.5 W 6.0 NW 5.0 SW 6.5 SW 12.5 N- 4.5 E 10.0 NW- 9.6 . NW 14.2 NW - 10.3 SW 8.4 NW - 7.8 NW 13.0 SW 9.4 SW 14.3 SW 13.6 . SW 5.1 w 3.7 ' s U. S. data from U. S. Weather Bureau. Canadian data from Meteorological Service of Canada.- 149 of and 1936American Society Heating Ventilating Engineers Guide, and walls (Tables 1 and 2, Chapter 6) must be based on the proper wind velocity for a given locality. In the case of tall buildings special attention must be given to infiltration factors. (See Chapter 6). In the past many designers, have used empirical exposure factors which were arbitrarily chosen to increase the calculated heat loss on: the side or sides of tKe building exposed to the prevailing winds. It is also possible to differentiate among the various exposures more accurately by calcu lating the infiltration and transmission losses separately for the different sides of the building, using different assumed wind velocities. Recent investigations indicate, however, that the wind direction indicated by Weather Bureau instruments does not always correspond with the direction of actual impact on the building walls, due to deflection by surrounding buildings. ' The exposure factor, which is still in use by many engineers, is usually taken as 15 per cent, and is added to the calculated heat loss on the side or sides exposed to what is considered the prevailing winter wind. There is a need for actual test data on this point, and pending the time when it can be secured, the question must be left to the judgment of the designing engineer. It should be remembered that the values of U in the tables in Chapter 5 are based on a wind velocity of 15 mph and that the infiltration figures are supposed to be selected from the tables in Chapter 6 to cor respond to the wind velocities given in Table 2 of the present chapter. The Heating, Piping and Air Conditioning Contractors National Associ ation has devised a method3 for calculating the square feet of equivalent direct radiation required in a building. This method makes use of ex posure factors which vary according to the geographical location and the angular situation of the construction in question in reference to pre vailing winds and the velocity of them. ' HEAT FROM SOURCES OTHER THAN HEATING PLAPfT The heat supplied by persons, lights, motors and machinery should always be ascertained in the case of theaters, assembly halls, and in dustrial 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 be allowed to affect the size of the installation at all, although they may have a marked effect on the operation and con trol of the system. In general, it is safe to say that where audiences are involved, the heating installation rftust have sufficient capacity to bring the building up to the stipulated inside temperature before the audience arrives. In industrial plants, quite a different condition exists, and heat sources, if they- are always available during the period of human occu pancy, may be substituted for a portion of the heating installation. In no case should the actual heating installation (exclusive of heat sources) be reduced below that required to maintain at least 40 F in the building. 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, which is See Standards of Healing, Piping and Air Conditioning Contractors National Association. - 150 Chapter 7--Heating Load 'n the room if the product being manufactured is not removed retained ture ;s the same as the room temperature. un*7 1 *c transmitted to the machinery from the outside, then only u^h^Teouivalent of the brake horsepower supplied is used. In the the heat equivaie Motor horsepower _ ,,, first case the Btu supplied per our Efficiency of motor ' ' case Btu per hour = bhp X 2,546, in which 2,546 is the nr^tilfivalent of 1 hp-hour. In high-powered mills this is the chief BtU heating and it is frequently sufficient to overheat the building "en in zero wither, thus requiring cooling by ventilation the year rThi heat (in Btu per hour) from electric lamps is obtained by multi- olvine the watts per lamp by the number of lamps and by 3.415. One TMhic foot of producer gas gives off about 150 Btu per hour; one cubic WK,onff ilnlumSinatignagsgSgaisveg^iveosff oaffboaubtou1t050305BBttuu ppeerr hhoouurr; anAd Woneelscbuabcihc burner averages 3 cu ft of gas per hour and a fish-tail burner, 5 cu ft per hour. For information concerning the heat supplied by persons, see Chapter 3. In intermittently heated buildings, besides the capacity necessary to care for the normal heat loss which may be calculated according to customary rules, additional capacity should be provided to supply the heat necessary to warm up the cold material of the interior walls, floors, and furnishings. Tests have shown that when a cold building has had its temperature raised to about 60 F from an initial condition of about O F, the heat absorbed from the air by the material in the structure may vary from 50 per cent to 150 per cent of the normal heat loss of the building. It is therefore necessary, in order to heat up a cold building within a reasonable length of time, to provide such additional capacity. If the interior material is cold when people enter a)building, the radiation of heat from the occupants to the cold material will be greater than is ' 1 rll^o/-vrvitirill rPci114" . (Sen I nflhfpr A V ... CONDENSATION ON BUILDING SURFACES4 Condensation on the interior surfaces of buildings is often a serious problem. Water dripping from a ceiling may cause irreparable damage to manufactured articles and machinery. It often results in short-cir cuiting of electric power and lighting systems, necessitating shut-downs and incurring costly repairs. It also causes rotting of wood roof struc tures, corrosion of metal roofs, arid'spalling and disintegration ofgypsum and other types of roof decks not properly protected. Condensation is caused by the contact of the warm humid air in a building with surfaces below the dew-point temperature, and can be remedied in two ways, (1) by increasing the temperature of such surfaces above the dew-point temperature, or (2) by lowering the humidity. Dehumidification, of course, is not advisable where a high relative humidity is necessary for manufacturing processes. Hence, the'only alternative is to increase the surface temperature by decreasing the inside 4See Preventing Condensation on Interior Building Surfaces, by Paul D. Close (A.S.H.V.E. Trans- . actions, Vol. 36, 1930). . 151 of andAmerican Society Heating Ventilating Engineers Guide, 1936 surface resistance. This can be accomplished by increasing the velocity of air passing over the surface, or by increasing the over-all resistance of the wall or roof by installing a sufficient thickness of insulation. . . The latter method is generally used, and the thickness of insulation is determined by ascertaining the amount of resistance to be added to increase the temperature of the interior surface above the dew-point temperature for the maximum conditions involved. This in turn is based on the fundamental principle that the drop in temperature is proportional to the resistance. See Question Hat the end of this chapter, EXAMPLES OF HEAT LOSS COMPUTATIONS Fig. 1. Elevation of Factory Building 1. Location__ ..Philadelphia, Pa. . 2. Lowest outside temperature. (Table 2)................................................................................ -- 6F 3. Base temperature: In this example a design temperature 10 F above lowest ' on record instead of 15 F is used.|yHence the base temperature = (- 6 + 10) = + 4 F. . 4. Direction of prevailing wind (during Dec., Jan., Feb.)_____ ____________Northwest .- -i 5. Breathing-line temperature (5 ft from floor)_____ ____________________________ ;;_.60 F 6. Inside air temperature at roof: The air temperature just below roof is higher than at the breathing line. Height of roof is 16 ft, or it is 16 -- 5 = 11 ft above breathing line. Allowing 2 per cent per foot above 5 ft, or 2 X 11 = 22 per cent, makes the tem- . . . .perature of the air under the roof = 1.22 X 60 = 73.2 F. \ ' 7. Inside temperature at walls: The air temperature at the mean height of the walls is greater than at the breathing line. The mean height of the walls is 8 ft and allowing 2 per cent per foot above 5 ft, the average mean temperature of the walls is 1.06 X 60 = 63.6 F. By similar assumptions ana calculations, the mean temperature of the glass will be found to be 64.2 F and that of the doors 61.2 F. : . 8. Average wind velocity (Table 2)___ ...:.............................I.............................. ;.11.0 mph 9. Over-all dimensions (See Fig. 1).,................................... ,................. ;...........;...... 120 x 50 x 16 ft 10. Construction: . Walls--12-in. brick, with J-in. plaster applied directly to inside surface; Roof--3-in. stone concrete and built-up roofing. ' 152 Chapter 7--Heating Load fIgor--5-in. stone concrete on 3-in. cinder concrete on dirt. Poors--One 12 ft x 12 ft wood door (2 in. thick) at each end. Windows--Fifteen, 9 ft x 4 ft single glass double-hung windows on each side. 11. Transmission coefficients: Walls--(Table 3, Chapter 5, Wall 2B)._,,................................. Roof__(Table 11, Chapter. 5, Roofs 2A and 3A)....------------ U = 0.34 TJ = 0.77 floor__ (Table 10, Chapter 5, Floors 5A and 6A)........... . __U = 0.63 Doors--(labie iod, \_napLei oj. ---........................................... .............. TJ = 0.46 Windows--(Table 13A, Chapter 5)----------------------------------...........U = 1.13 12. Infiltration Coefficients:, Windows__ Average windows, non-weatherstripped, crack and Hi-in clearance. The leakage per foot of crack for an 11-mile wind velocity is 25.0 cfh. (Determined by interpolation of Table 2, ' Chapter 6.) The heat equivalent per hour per degree per foot of crack is taken from Chapter 6. 25.0 X 0.018 = 0.45 Btu per deg Fahr per foot of crack. Poors__ Assume infiltration loss through door crack twice that of windows or 2 X 0.45 = 0.90 Btu per deg Fahr per foot of crack. Walls--As shown by Table 1, Chapter 6, a plastered wall allows so little infiltration that in this problem it may be neglected. 13. Calculations: See calculation sheet, Table 3. Table 3. Calculation Sheet Showing Method of Estimating Heat Losses of Building Shown, in Fig. 1 Part of Building Width in Feet Height in Feet Net Sur face Area or Crack Length COEFFI CIENT North Wall: Brick, J^-in. plaster............. ... Doors (2-in. wood)_________ in. Crack.. ........................ 50 16 12 12 1 pair doors 656 , 144 60 0.34 0.46 0.90 West Wall: Brick, K-in. plaster................ Glass (Single)...... ......... -......... % in. Crack..... ......................... South Wall..................................... East Wall..................................... Roof, 3-in. concrete and slag surfaced built-up roofing____ Floor, 5-in. stone concrete on 3-in. cinder concrete________ 120 16 15 x 4 1 9 Double Hung Windows (15) 1380 540 450 . Same as North Wall Same as West Wall 50 120 6000 50 120 6000 0.34 . 1.13 0.45 0.77 0.63 Temp. Diff. 59.6 57.2 57.2 59.6 60.2 60.2 a 69.2 5b Total Btu 13,293 3,789 1.544a 27,964 36,734 , 6,095a 18.626 70,793 319,704 18.900 Grand Total of heat required for building In Btu per hour. 517,442 "Thig'building has no partitions and whatever air enters through the cracks on the windward side must leave through the cracks on the leeward side.- Therefore, only one-half of the total crack will be used in computing infiltration for each side and each end of building. ' bA 5 F temperature differential is commonly assumed to exist between the air on one side of a large- floor laid on the ground and the ground. . f of andAmerican Society Heating Ventilating Engineers Guide, 1935 PROBLEMS IN PRACTICE X What is the relation between the sensible heat loss from a building and the heat required for humidification? A house with a volume of 14,000 cu ft has a heat loss 120 Mbh for standard uninsulated frame construction and a 70 F temperature difference. Assuming a leakage rate of air changes per hour it would require about 10 Mbh to maintain a relative humidity of 45 per cent when the outside air is 0 F and 50 per cent relative humidity. By usjJJ an insulation such as rock wool, the sensible heat loss of this house may be reduced to approximately 77 Mbh. The insulation'does not affect the humidification load, which now assumes greater importance. . 2 What inside dry-bulb temperatures are usually assumed for: (a) homes, ' (b) schools, (c) public buildings? 1 Referring to Table 1: o. 70 to 72 F. b. Temperature varies from 55 to 75 F, depending on the room. Classrooms, for instance, are usually specified as 70 to 72 F. . ' c. 68 to 72 F. 3 How is the outside temperature selected for use in computing heat losses? The outside temperature used in computing heat losses is generally taken from 10 to 15 F higher than the lowest recorded temperature as reported by the Weather-Bureau during the preceding 10 years for the locality in which the heating system is to be installed. In some cases where the lowest recorded temperature is extremely unusual, the design temperature is taken even higher than 15 F. above the lowest recorded temperature. 4 What are the effects of wind movement on the heating load? a. Wind movement increases the heat transmission of walls, glass, and roof; it affects poor walls to a much greater extent than good walls. b. Wind movement materially increases the infiltration (inleakage) of cold air through the cracks around doors and windows, and even through the building materials them selves if such materials are at all porous. - 5 f Calculate the heat given off by eighteen 200-watt lamps. 200 X 18 X 3.415 = 12,294 Btu per hour. ; 6 A two-story, six room,; frame house, 28-ft by 30-ft foundation, has the following proportions: . Area of outside walls, 1992 sq ft. - Area of glass, 333 sq ft. . Area of outside floors, 54 sq ft. Cracks around windows, 440 ft. Cracks around doors, 54 ft. . Area of second floor ceiling, 783 sq ft. t Volume, first and second floors, 13,0X0 cu ft. Ceilings, 9 ft high. . .' < The minimum temperature for the heating season is --34 F, and the required inside temperature at the 30-in. level is 70 F. The average number of degree days for a heating season is 7851, and the average wind velocity is 10 mph, northwest. ' The walls are constructed of 2-in. by 4-in. studs with wood sheathing,- building paper, and wood siding on the outside, and wood lath and plaster on the inside. Windows are single glass, double-hung, wood, without weatherstrips. The second floor ceiling is metal lath and plaster, without an attic floor. - The. roof is of wood shingles on wood strips with rafters exposed. The area of the roof is 20 per cent greater than the area of the ceiling. Select values for the following: (a) U for walls; (b) U for glass; (c) U for second floor ceiling; (d) U for roof; 154 Chapter 7--Heating Load -r a and roof combined; (f) air leakage, cubic feet per hour per foot (e) il fr jgj ajj. leakage, cubic feet per hour per foot of door crack, of window cr ^ 0.25 (Table7 5; Chapter 5). =' ' : .' . b 1.13 (Table 13, Chapter 5). c 0.69 (Table 8, Chapter 5)., . d. 0.46 (Table 12, Chapter 5). e 0.236 (Equation 6, Chapter 5). /. 21.4 (Table 2, Chapter 6). , . ., it the data of Question 6, calculate the maximum Btu loss per hour for 7 Using in onstructions, and show the percentage of the total heat which is lost through each construction described. . ,, o rent rise in temperature for each foot in height. The average temperature ^UbeW sTf for walls, doors, and windows, and 79.1 F for the second floor ceiling. o. Outside walls b. Glass c. Doors .. d. Second floor ceiling c. Air leakage, windows /. Air leakage, doors 46,200 Btu loss 34,950 Btu loss 5,670 Btu loss 17,840 Btu loss 15,750 Btu loss 3,865 Btu loss 37.2 per cent of total 28.1 per cent of total 4.6 per cent of total 14.3 per cent of total 12.7 per cent of total 3.1 per cent of total Total 124,275 Btu loss 100.0 per cent of total 8 For the house in Question 6, place 1-in. insulation in the outside walls and second floor ceiling; k for insulation = 0,34. Use weatherstrip on doors and windows, and double glass on the windows; Ca = 0.55. Calculate or select the following values: (a) U for walls; (b) U for glass; (c) U for second floor ceiling; (d) U for combihation of ceiling and roof; (e) air leakage, cubic feet per hour per foot of door crack; (f) air leakage, cubic feet per hour per foot of window crack. a. 0.144. b. 0.55. c. 0.23. d. 0.13. e. 15.5. /. 31.0. . 9 Calculate the maximum Btu loss per hour and show the percentage loss by each channel for the house as insulated in Question 8. a. Outside walls b. Glass -d. Doors d. Ceiling _ e. Air leakage, windows /. Air leakage, doors 26,650 Btu loss 17,000 Btu loss 5,670 Btu loss 10,070 Btu loss 11,400 Btu loss 2,795 Btu loss 36.2 per cent of total . 23.1 per cent of total 7.7 per cent of total 13.7 per cent of total 15.5 per cent of total 3.8 per cent of total Total 73,585 Btu loss ' 100.0 per cent of total 10 From the results of Questions 7 and 9, calculate the Btu saved and the percentage saved by each change in construction. Uninsulated Insulated Btu 8aved Peb Cent Sated a. Outside walls b. Glass c. Doors d. Ceiline.......... L Air leakage, windows /. Air leakage, doors 46,200 34,950 5,670 17,840 15,750 3; 865 26,650 17,000 5,670 10,070 11,400 2,795 19,550 17,950 0 7,770 4,350 1,070 42:3 51.4 0 . 43.5 27.6 .27.7 ' 155 Chapter 8 COOLING LOAD Conditions to be Maintained, Cooling Load, Transmission for Surfaces not Exposed to the Sun, Outside Temperatures, Solar Radiation, Time Lag, Transmission of Solar Radiation Through Glass, Heat and Moisture Leakage, Heat and Moisture Sources THE method of calculating the cooling load is similar to that used in calculating the heating load. The direction of the flow of heat is reversed, however, and in most cases additional factors must be con sidered, such as solar radiation and the heat from occupants, lights, motors,' and other sources. The character of the load depends on the type of building to be cooled as, for example, in auditoriums and other places of assemblage where the maximum load usually is that due to the heat and moisture given off by the occupants, or in office buildings and residences . where solar radiation and the transmission and infiltration of heat through the building shell are most important. While cooling is generally identified with the summer season, it is often necessary to cool in winter as well as in summer. In a crowded place of assemblage the heat given off by the occupants, together with that given off by the lighting and power equipment, may be more than the normal heat loss through the structure even in winter under cold climatic con ditions. . Much of the basic information for the design of comfort conditioning installations has resulted from research conducted at the A.S.H.V.E. Research Laboratory and at institutions with which cooperative research investigations have been carried on. These data include the effective temperature index, and heat and moisture loss data given in Chapter 3. : COMFORT CONDITIONS The conditions to be maintained in an enclosure are variable and depend on many factors, especially the season of the year and (during the summer) the outside dry-bulb temperature and the duration of the period of occupancy. Information concerning the proper effective temperatures to be maintained for various seasons is given in Chapter 3, where are also tabulated the most desirable indoor air conditions to be maintained in summer for exposures less than three hours. (See Table 2, Chapter 3.) In installations for restaurants and theaters the.:requirements are different from those in offices, since there must be a considerable volume of air circulated in order to provide ventilation and cooling. ,- 157 American Society of Heating and Ventilating Engineers Guide, 1936 Table 1. Design Dry- and Wet-Bulb Temperatures, Wind Velocities, and Wind Directions for June, July, August, and September Stats ClTT Ala.. Birmingham__ Mobile.________ Ariz............. Phoenix.______ Ark_______! Little Rock___ Calif______ Los Angeles..... Colo______ San Francisco.. Denver.............. Conn. D. C.......... Fla________ New Haven..... . Washington...... Jacksonville...... Ga____ Tampa.. Atlanta...... ...... '........ Savannah................. Idaho... Ill_____ Boise.______ ---....... Chicago--------- .------- Peoria........................ Ind______ Indianapolis............ Iowa..____ Ky----------- La.............. Des Moines...... i...... Louisville.........-...... New Orleans............ Maine___ Portland............ ....... Md____ __ Baltimore................ - Mass......... Boston...... ................. Mich...... .. Detroit... Minn_______ Minneapolis... Miss. Vicksburg....... Mo'..__ Kansas City... St. Louis......... Mont.......... Helena_______ Nebr........ Nev. N. J---------- N. Y........... Lincoln______ Reno.. Trenton_____ Albany.......... Buffalo.......... New York.__ N. M___ Santa Fe___ N. C...__ Asheville-- Wilmington_____ N. Dak... Bismarck...... ....... Ohio____ Cleveland_______ Cincinnati---------- Okla____ Oreg-----Pa.,,........ Oklahoma City.. Portland_______ _ Philadelphia____ Pittsburgh........... R.I_____ . s. c__ Providence........ . Charleston--.-- Greenville-........... Tenn.:_______ Chattanooga------ . Memphis..... ........ Texas--.--. Dallas.. Galveston___ San Antonio.. Houston......... El Paso._____ Design Dry-Bulb Desiq Wbt-Be ] SumrEB Wind Velocity MPff Pbbvah&q Summer Wind Direction ... 93 ._ 94 ... 110 .. 95 - 88 .. 85 .. .95 .. 94 .. 94 . 91 . 95 . 95 . 95 . 91 . 90 . 92 . 94 94 85 93 88 93 93 95 92 95 87 93 93 95 90 83 95 87 87 93 88 95 ?\ 95 96 83 95 ' 91 85 94 93 94 . 93 99 93 100 93 98 77 78 77 77 70 68 64 74 78 .78 79 75 79 65 ' 75 75 73 74 75 79 71 76 73 73 72 78 75 78 63 74 64 76 74 72 75 63 72 79 69 75 78 76 65 78 73 73 80 76 76 77 76 .79 78 79 69 5.2 8.6 6.0 7.0 6.0 11.0 6.8 7.3 6.2 8.7 7.0 7.3 7.8 5.8 10.2 8.2 9.0 6.6 8.0 7.0 7.3 6.9 9.2 10.3 8.4 6.2 9.5 9.4. 7.3 9.3 7.4 10.0 7.1 12.2 12.9 6.5 5.6 7.8 8.8 9.9 6.6 10.1 6.6 9.7 9.0 10.0 9.9 6.8 6.5 7.5 9.4 9.7 7.4 7.7 6.9 S SW W NE SW SW s s s SW E NW SW NW NE S SW SW SW SW S SW SW SW SE SW .s SW SW S w SW S SW SW SE SE SW NW S SW s NW SW NW NW SW . NE' SW SW s. _ s SE s E.' 168 . I Chapter 8--Cooling Load i Design Dry- and Wet-Bulb Temperatures, Wind Velocities, and "^ABLByJiND Directions for June,'July, August, and September (Continued) _-- r*T* Cm c Design Dbt-Bdlb Design Wet-Bulb Summer Wind MPH. Velocity Prevailing Summer Wind Direction Utah- Salt Lake City.--------------------- Vt----........... Va---- Richmond--................................ Seattle.......................................... Spokane-..... -............................. a........... Wis.-- Madison...................................... Milwaukee...........................-- Cheyenne-................................. --- 95 85 91 95 83 89 90 89 93 85 67 8.2 71 8.9 76 10.9 78 6.2 61 7.9 63 6.5 74 5.3 73 8.1 74 10.4 62 9.2 SE s S SW s SW SE SW S S COOLING LOAD The cooling load may be divided into the following parts: 1. Transmission of heat through walls, roof, and glass with allowances for sunexposed surfaces and heat capacity. 2. Transmission of solar radiation through glass and absorption by interior furnishings. 3. Heat and moisture from infiltration and from outside air introduced. (. Heat and moisture from occupants and heat from lights, machinery and other sources. Transmission for Surfaces Not Exposed to the Sun The transmission load for surfaces not exposed to the sun is calculated in a manner similar to that described in Chapter 7, by means of the following formula: Hi = A V (to - t) (1) where Ht - heat transmitted through the material of the wall, glass, roof, or floor, Btu per hour. . A = net inside area of wall, glass, roof, or floor, square feet. t = inside temperature, degrees Fahrenheit. lo = outside temperature, degrees Fahrenheit. V = coefficient of transmission of wall, floor, roof or glass, . Btu per hour per square foot per degree Fahrenheit difference in temperature. (Tables 3 to 13, Chapter 5.) Outside Temperatures Summer dry-bulb and wet-bulb temperatures for various cities are given in Table 1. It will be noted that the temperatures are riot the maximums but the design temperatures, which should be used in air conditioning calculations. The maximum outside wet-bulb temperatures as given in Weather Bureau reports usually occur only from 1 per cent to 4 per cent of the time, and they are therefore of such short duration that it is not practical to design a cooling system covering this range. The temperatures shown in Table 1 are based on a study of hourly tempera tures in New York City from which factors were derived and applied to 159 American Society of Heating and Ventilating Engineers Guide, 1936 the average maximum dry- and wet-bulb temperatures for other cities. This study covered a twenty-year record of Weather Bureau tempera tures. The design temperatures given are not exceeded more than 5 to 8 per cent of the time during a cooling season of 1200 hours in June, July August, and September for an average year. ' Solar Radiation , Fig. 1 shows the total amount of solar energy in Btu per square foot per hour received during the day by a surface normal to the rays of the sun, by a horizontal surface, and by east, west, and south walls. The curves are drawn from A.S.H.V.E. Laboratory data obtained by pyrheliometer, are based on sun time, and are for a perfectly clear day on August 1 at a north latitude of 40 deg. Data from these curves may be used with little error for most United States latitudes and for all of the hotter months of the year. The absorption of solar radiation by a surface depends upon the character of the surface and the angle of the surface with respect to the direction of the radiation. The heat absorption by a black oilcloth surface perpendicular to the sun's rays was found to be as high as 273 Btu per square foot per hour, based on tests conducted by the A.S.H.V.E. Research Laboratory in Pittsburgh1. Lamp black, red brick dust, and aluminum bronze painted surfaces perpendicular to the sun's rays showed, respectively, 94.0, 63.4, and 28.2. per cent as high a rate of absorption as the black oilcloth. Table 2. Allowance for Solar Radiation on Roofs and Walls Approximate Number of Degrees to Add to Dry-Bulb Temperature for Different Types of Surfaces . Type op Surface Black Red Brice oa Tile Paint Roof, horizontal...................................... ............... East or west wall...................................................... South wall............. ............................................... ..... 45 30 15 30 20 10 .15, 10 -5 - Solar radiation is an important factor in the mechanism of heat flow into buildings. Research conducted at the A.S.H.V.E. Research Laboratory2 has shown that a large error may be. introduced into the calculations by failure to consider the periodical character of heat flow resulting from the diurnal movement of the sun and the heat capacity of the structure, which determine the timing and magnitude of the heat wave flowing through the wall into a building on a hot, sunny day. Unfortunately, the calculations for the transmission of heat from solar radiation through building walls are too complicated to be of much 'Absorption of Solar Radiation in Relation to the Temperature, Color. Angle, and Other Characteristics of the Absorbing Surface, by F. C. Houghten and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 36.1930). 'For further information on this subject see following A.S.H.V.E. research papers: Coefficients of Heat Transfer as Measured under Natural Weather Conditions, by F. C. Houghten and C. G. F. Zobel (A.S.H. V.E. Transactions, Vol. 34, 1928);. Absorption of Solar Radiation in Its Relation to the Temperature. Color. Angle and Other Characteristics of the Absorbing Surface, by F. C. Houghten and Carl Gutberlet (A.S.H.V.E. Transactions, Vol. 36, 1930); 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.E. Trans actions, Vol. 38, 1932). . 160 wt- Chapter 8--Cooling Load American Society of Heating and Ventilating Engineers Guide, 1936 practical value to the heating and ventilating engineer. Approximate results may be obtained by adding the number of degrees given in Table 2 to the outside design dry-bulb temperature in calculating the heat trans mission through a wall or roof which may be exposed to the sun for an appreciable length of time. Table 2 was obtained from a study of the data .in A.S.H.V.E. research papers on solar radiation1- 3. Black and aluminum painted surfaces represent the extremes which are likely to occur. For other types of surfaces, values intermediate between those given in the table can be used. Time Lag The calculation of heat transmitted through walls and roofs does not take into consideration the heat capacity of the structure and the con sequent time lag in the transmission of heat. In the thick walls used in modern office buildings the time lag may amount to 10 hours or more4. Thus in many cases the wall transmission cannot be added directly to the cooling load from other sources because the peak of the wall transmission load may not coincide with the peak of the total cooling load and may even occur after the cooling system has been shut down for the day. The data in Table 3 were taken from A.S.H.V.E. research papers8, 4 and while they result principally from a study of experimental slabs, they give an idea of the time lag to be expected in various structures. Table 3. Time Lag in Transmission of Solar Radiation through Walls and Roofs ------------------------------------ J-- --------------------------------------- --------------------- ' Ttfs and Thickness or Wall on Roor . Tub Lao, Houbb . 2-in. pine................. 6-in. concrete....................... 4-in. nypsum..... .................................................... 3-in. concrete and 1-in. cork............... 2-in. iron and cork (equivalent to %-in. concrete and 2.15-in rnrtr) 4-in. iron and cork (equivalent to 5H-in. concrete and 1.94-in. cork) ........ 8-in. iron and cork (equivalent to 16-in. concrete and 1.53-in. cork)................ 22-in. brick and tile wall 3 2H 2 2/'& 7H 19 10 In' intermittently cooled buildings the cooling capacity must be sufficient to care for the load imposed by the necessity to cool down the furnishings and the material of the interior construction to the point-of maintained temperatures. Transmission of Solar Radiation Through Glass In considering the transmission through glass several factors must be considered. As the sun's rays impinge against a pane of glass, most of the radiation passes through to the other side, a small amount is reflected, and the balance is absorbed by the glass. The amount absorbed depends upon the character and thickness of the glass and the angle between the sun's rays and the glass. The temperature of the glass is raised by the absorbed `Heat Transmission zs Influenced by Heat Capacity and Solar Radiation, by F. C. Houghten,' J, L. Blackshaw, E. M. Pugh, and Paul McDermott (A.S.H.V.E. Transactions, Vol. 38, 1932). `Field Studies of Office Building Cooling, by J. H. Walker, S. S. Sanford, and E. P. Wells (AS H V E. Transactions, Vol. 38, 1932). . Chapter 8--Cooling Load , ,|1s is then delivered to the air on the two sides of the glass heat an rtion to the difference between glass and air temperatures. in Trh A S H V.Er?. at.e.--sdt-srs indicated ttlhiaatt 3a csinincgrllae npaannpe ooff Hdrotuiihbllpe ssttrrperngth 1 127 in. thick absorbs approximately 11 per cent of the solar g action passing through it when the impingement is normal. For fa her angles of impingement, the glass retards percentages of the total S"rrant energy approximately in proportion to the sine of the angle, nrher experiments4 indicate a glass absorption of 16.7 per cent for one pane of glass and.37.5 per cent for.two 34-in. panes separated by a 1%-m. ^The amount of solar radiation delivered to an unshaded glass surface mav be obtained from the curves in Fig. 1. For surfaces other than those viven the solar radiation incident to the glass must be calculated. Hendrickson and Walker* have shown how this may be done if the wall faces some direction other than east, west, or south. They have also shown how to calculate the net glass area on which the solar radiation impinges when the glass is partly shaded by the frame or wall. The values from Fig. 1 must be used only for the net glass area on which the sun shines. Tests at the A.S.H.V.E. Research Laboratory8 have deter mined the percentages of heat from solar radiation actually delivered to a room with bare windows and with various types of outdoor and indoor shading.- The data in Table 4 are taken from these tests. Table 4. Solar Radiation Transmitted through Bare and Shaded Windows Ttpe or Appcbtenancb Psb Cent Dzljvebed to Room 97 28 45 68 58 22 The percentage figures in this table were obtained by dividing the total amount of heat actually entering through the shaded window by the total amount of heat calculated to enter through a bare window (solar radiation plus glass transmission based on observed outside glass tem perature). For bare windows on which, the sun shines, the transmission of heat from outside air to glass is small or negative as the glass tem perature is raised by the solar radiation absorbed. Therefore, in calcu lating the total heat gain through windows on the sunny sides of buildings, it is sufficiently accurate to figure the total cooling load due to the window, as the solar radiation times the proper factor from Table 4, and to neglect the heat transmission through the glass caused by the difference between the temperatures of the inside and outside air. Another reason for neglecting this glass transmission load is that the curves in,Fig. 1 were Summer Cooling for Comfort as Affected by Solar Radiation, by G. A. Hendrickson and J. H. Walker, Seating and Ventilating, November, 1932, and The Determination of Sun Effect on Summer Cooling Loads, by G. A. Hendrickson and J. H. Walker, Heating and Ventilating, June, .1933, Studies of Solar Radiation Through Bare and Shaded Windows, by F. C. Houghten, Carl Gutberlet, and J. L. Blackshaw (A.S.H.V.E. Transactions, Vol. 40, 1934). , 163 of andAmerican Society Heating Ventilating Engineers Guide, 1936 based on the maximum intensity of solar radiation observed at the A.S.H.V.E. Laboratory during a three-year study, so results based on these curves will be amply high. It will be noted that Table 4 gives the amount of heat delivered through the window as 97 per cent of the solar . radiation, which is greater than is indicated by the figures for absorption in the preceding paragraph. The explanation is that much of the radia tion absorbed by the glass is delivered to the room. Although 97 per cent of the heat from solar radiation is delivered to a room through bare window glass, more recent tests7 have indicated that in the case of buildings having floors of high heat capacity such as con crete floors on which the solar radiation falls, approximately one-half of the heat entering a bare window is absorbed by the floor and does not immediately become a part of the cooling load but is delivered back to the air in the building at a slow rate over a period of 24 hours or longer. _ Fig. 1 shows that the maximum solar intensity on any surface is of limited duration. In the case of windows the total energy impinging on the glass before and after the time of maximum intensity is further reduced by increased shading of the glass from the frame, or wall. The cooling load due to solar radiation therefore does not have to be figured as a steady load. Another point which should be noted is that the maximum solar radiation load on an east wall occurs early in the morning when the outside temperature is low. . In a paper by the A.S.H.V.E. Research Laboratory8 it was shown that ordinary double strength window glass transmits no measurable amount of energy radiated from a source at 500 F or lower; that it transmits only 6.0 and 12.3 per cent of the total radiation from surfaces at 700 F and 1000 F, respectively; and that it transmits 65.7 per cent of the radia tion from an arc lamp, 76.3 per cent of the radiation from an incandescent tungsten lamp, and 89.9 per cent of the radiation from the sun. Thus, glass windows in a room constitute heat traps, which allow rather free transmission of radiant energy into the room from the sun to warm objects in it, but do not allow the transmission of re-radiated heat from these same objects. ' ,.. C ' Tests4 have been made which indicated that sunshine through window glass is the most important factor to contend with- in the cooling of an office building. At times it was shown to account for as much as 75 per cent of the total cooling necessary. Because of he importance of the sunshine load, cooling systems should be zoned so that the side of the building on which the sun is shining can be controlled separately from the other sides of the. building. If buildings are provided with awnings so that the window glass is shielded from sunshine, the amount of cooling required will be reduced and there will also be less difference in the cooling requirements of different sides of the building. The total cooling load for a building exposed to the sun on more than one side is of course less than the sum of the maximum cooling loads in the individual rooms "since the maximum solar radiation load on the different sides occurs at different times. In determining the total cooling load for a building if the ^me i! h %i -:r ' S/ i , 'Cooling Requirements of Single Rooms in a Modern Office Building, by F. C. Houghcen, Carl Gutberiet, and Albert J. Wahl (A.S.H.V.E. Journal Section, Healing, Piping and Air Conditioning. April, 1935>. 8Radiation of Energy Through Glass, by J. L. Blacksbaw and F. C. Hoiighten (A.S.H.V.E. Trans actions, Vol. 40, 1934). 164 Chapter 8--Cooling Load eh maximum load occurs is not obvious, the load should be calcu- when tne n 0f <jay to determine the time at which the sum of Se^oids on the different sides of the building is a maximum. . Heat and Moisture Leakage . iiowance must be made for the heat and moisture in the outside air e oHnced for ventilating purposes or entering the building through 1 cks crevices, doors, and other places where infiltration might occur. Cr The'volume of air entering due to infiltration may be estimated from , iven in Chapter 6 using wind velocities from Table 1, Chapter 8. Information on the amount of outside air required for ventilation will be found in Chapter 3. . .... , , ,. The heat gain resulting from the outside air introduced may be esti mated from the following formula: " Hi = 60 Qdo (80 - 8), . (2) where H = heat to be removed from outside air entering the building, Btu per hour. Q = volume of outside air entering the building, cubic feet per minute. do = density of outside air, pounds of dry air per cubic foot of outside air, at the temperature to- 8 = heat content of mixture of outside dry air (at temperature to) and water vapor, Btu per pound of dry air. . ' 8 = heat content of mixture of inside dry air (at temperature t) and water vapor, Btu per pound of dry air. Heat and Moisture Sources Figs. 8 to 11, Chapter 3, show the heat and moisture given off by human beings under various conditions of activity. For average conditions whej-e a person is normally at rest, as in a theater, or doing very light work, as in a restaurant or residence, the total amount of heat given off will average Table 5. Heat Gain Due to Various Devices, Btu per Hour Lights and electrical appliances........ ......... ..... Motors with connected load in same room3.. Nameplate rating, H.to Yi hp..... ..... ........... Nameplate rating, to 3 hp................ Nameplate rating, 3 to 20 hp....................... Restaurant coffee urns, 10-gal capacity.------- Dish warmers per 10 sq ft of shelf.................. . Restaurant range--4 burners and oven_____ Residence gas range Giant burner............... ...................................... . Medium burner............ .............................. .. Oven..... ......... ............................ ............. Pilot............................... ........ ........ ................... Electric range . Small burner, 1000 to 1350 watts.... ........... Barge burner, 1700 to 2200 watts...... ........ Oven, 2000 to 3000 watts...................... ....... Appliance connection, 660 watts................ Warming compartment, 300 watts.--........ Deduct 2545 Btu perhp if connected load is outside of room. ' 165 3,413 per lew 4,250 per hp 3,700 per hp 2,950 per hp 16,000 6,000 100,000 12,000 9.000 . 1.000 per cu ft of space 250 3,413 per kw 3,413 per kw 3,413 per kw . 2,250 1,025 ' of andAmerican Society Heating Ventilating Engineers Guide, 1935 about 400 Btu per hour. Part of this is latent heat due to the evaporation of 700 to 1200 grains of moisture per hour. Examples illustrating heat and moisture loss calculations for human beings are given in Chapter 3. All sources of heat must of course be considered in designing the con ditioning system. The heat gain due to various devices is given in Table 5. Moisture evaporated by appliances must be included, in the total latent heat load. In some cases only a small part of the heat from lights immediately affects the cooling load. Tests7 show that with lights placed near the ceiling under some conditions the electricity used for illumination has little effect on the cooling load in an office cooled during the usual short period. The air heated by the lights stratifies closely to the ceiling and the temperature of the lower layers of air is raised only a small amount after a considerable lapse of time. An example of cooling load calculation is given in Chapter 9. PROBLEMS IIS PRACTICE 1 # In buildings such as an office building which is cooled intermittently, will the maximum cooling load, occur coincidently with the maximum dry. bulb temperature? Not. necessarily. . Tests indicate that particularly for east and south exposures the maxi mum rate of. cooling occurs shortly after the equipment is started in the morning. This extra heat is that which was absorbed by the building during the preceding day and also during' the off period. The rapid lowering of the room temperature after the cooling equipment is started causes this stored up heat to flow quickly from wall and floor surfaces to the room air. . 2 The outdoor and indoor temperatures are 90 F and 78 F, respectively! What is the amount of beat transmitted per hour through a 7 ft by 4 ft north window? Ht - 28 X 1.13 (90 - 78) = 380 Btu per hour. ' (Equation 1, Chapter 8 and Table 13, Chapter 5.) 3 What are the proper design temperatures for a Detroit store? . Outdoor dry-bulb, 93 F; wet-bulb, 73 F. (Table 1, Chapter 8.) Indoor dry-bulb, 79.2 F; wet-bulb, 64.8 F. (Table 2, Chapter 3.) " ,- c , .` 4 a. What is the maximum heat transmission for a flat roof exposed to the sun with the outdoor and indoor temperature 95 F and 80 F, respectively? The roof is of uninsulated 6-in. concrete, 'with its underside exposed, and with a black upper surface. . b. If the temperatures specified were the maximum for the day and1 occured at 12 o'clock, at what time would the maximum cooling load due to the roof exist? a. Ht = 1 X 0.64 (95 + 45 -- 80) = 38.4 Btu per hour per square foot. (Equation 1 and Table 2, Chapter 8, and Table 11, Chapter 5.) . b. At 3 p.m. (Table 3.) '. . * '. 5 For south windows equipped with canvas awnings, what is the maxitfcum amount of heat delivered to a room when the outdoor temperature is 90 F and the indoor temperature is 78 F? 115 X 0.28 = 32.2 Btu per square foot of glass (Fig. 1 and Table 4; note that glass transmission can be neglected). . . , 166 Chapter 8--Cooling Load . the heat cat" P* cubic foot of outside air introduced, under the 6# What is following conditions: Outdoor temperatures, 90 F dry-bulb and 75 F wet-bulb Inside temperatures, 78 F dry-bulb and 65 F wet-bulb Hi = 60 Qdo (9o -- 8). (From Equation 2.) . . Tvohl.eumreelaotrfiv1,elIbKhunomff aidviritiyso1--3-f-.-t8-h-4-e- outdoor air 1+. 14.53 -- is tx 5i0n ^perf4Cc.ee~nntt UrpV,, chrometr. ic Chart>),' aanuda- tmhee = 14.19 cu ft (Table 5, Chapter 1). 1 = 0.0704. do = Till 13.^ t6uore=m3a8y.4b6eaonbdta6ine=d2f9ro.9m6 (tThaeblales5t ,cColhuampnteirn1T).abTlehe5toCtahlanter ?* Kny air'.v.aP?r nux- temperatures to be wet-bulb readings, since the total heat nt* -J.' considering the give^-et-bulb temperature. 8 heat of a mixture 1S constant for a Hi = 0.0704 (38.46 - 29.96) = 0.598 Btu per cu ft. 7load dIuf ethteoreligahrtes?twenty 200-watt lights in use in a room, what is the cooling 200 X 20 = 4000 watts -- 4 Jew. 3413 X 4 = 13,652 Btu per hour (Table 5, Chapter 8). 8 a. If a restaurant has two 10-gal coffee urns, what is the cooling load due to them? b. What is the cooling load due to four 1350-watt burners on an electric range? a. 16,000 X 2 = 32,000 Btu per. hour (Table 5, Chapter 8). b. 1.35 X 4 X 3413 = 18,430 Btu per hour (Table 5, Chapter 8). 9 Why may the heat gain by transmission through glass on the sunny ex posures be neglected? - Solar radiation on a glass surface during peak hours will cause the outer surface of the glass to rise up to or slightly above the simultaneous air temperature, hence no heat can flow from outside air to the glass at this time. 10 What should be the dry- and wet-bulb temperatures in a restaurant when the outdoor dry-bulb temperature is 95 F? Dry-bulb, SO F; wet-bulb, 65 F (Table 2, Chapter 3). 11 In an office building in which the occupants remain indoors most of the day, what is the most desirable indoor dry-bulb temperature and relative humidity in summer? 76.5 F and 50 per cent relative humidity (Fig. 5, Chapter 3). 12 An office with western exposure in a building having concrete floors is cooled only during office hours. If the windows are bare and unshaded, what is the maximum Cooling load in the office due to solar radiation through the windows? 215 X 0.97 X H = 104 Btu per square foot of glass per hour (Fig. 1 and Table 4; note that only one-half of the heat need be considered because of absorption by the floor). 13 # A 7 X 4 ft west window is equipped'with an inside Venetian blind which is adjusted to fully cover the window when the sun shines. The net glass area is 75 per cent of the total area of the window. What is the cooling load due to the window at 10 a.m. and 4 p.m. assuming solar radiation as shown in Fig. 1 and 167  Chapter 9 CENTRAL AIR CONRITIONING SYSTEMS .. ;.; Types of Systems, Dehtimidifiers, Designing the System, Zoning, j [location of Apparatus, Temperature of the Air Leaving Inlets, Air Quantity Required, Heat to be Removed by Cooling and . Dehumidifying Apparatus, Size of Reheaters, Surface Cooling ' Problems, Auxiliary Equipment , . CENTRAL systems, equipped for cooling and dehumidifying, are used principally in the air conditioning, of theaters, restaurants, office buildings, or other places where people gather, and in manufacturing establishments where air conditions have an important influence on the quality of product or rate of production. A central cooling and dehu midifying plant is one in which the fans, dehumidifiers, and other related apparatus are assembled in suitable apparatus rooms from which supply and return ducts lead to the conditioned spaces. . The design of such systems is considered in this chapter, while in Chapter 22 central systems for heating and humidifying are described; Air conditioningfor industrial processes is considered in Chapter 40. TYPES OF SYSTEMS Dehumidification or cooling of air may be accomplished by several' methods and by use of many heat transfer mediums. Most comfort conditioning, central station, air-conditioning systems employ cold water: or the direct expansion of a refrigerant in either spray type or surface type equipment to accomplish the required cooling and dehumidification. Among the several other methods that may be employed are: passing the air through or over a dehydrating agent and then lowering the dry-bulb; temperature to the proper level, and evaporative cooling. With the' former method the excess sensible heat may be removed with Cold water and where this is not available, mechanical refrigeration must be used after the air has been dehydrated; The latter method is applicable to comfortjConditioning only in regions where the summer wet-bulb tem perature is low;.. : .. ...... If the system is intended solely for summer conditioning, the apparatus will consist essentially of a dehumidifier of the surface type or spray type-;) filters; fan and motor; reheater; outside air, return airj and supply air duct; work; air inlets and outlets; spray pump for spray dehumidifier; refrigera- > tion equipment; and suitable controls.' Generally, however,. a ^central; station air conditioning system is designed for year-round service. This means that properly sized heaters and dehumidifiers. with their respective 169: American Society of Heating and Ventilating Engineers Guide, 1936 controls, must be added. With few exceptions, systems designed to meet summer capacity requirements will have ample capacity for winter and intermediate season conditioning. A common arrangement of a central station spray type system for cooling and dehumidifying is illustrated in Fig. 1. The plant may be designed to condition 100 per cent outside air, 100 per cent return air, or a mixture of outside and return air. Further, part of the air returned from the conditioned space may be by-passed1 around the conditioner as illustrated in Fig. 2. The reheater may be installed in the fan inlet chamber as shown, in the by-pass air duct, or in the fan discharge duct, depending upon apparatus space and other design conditions. Still another arrangement of equipment will result if the dehumidified air fan delivers the conditioned air to several other fans rather than to the con which restrict the use, in comfort conditioning applications, of refrigerants acting by direct expansion in coils exposed to the air stream. -Therefore local codes should be consulted by the designer before he pldhs a system employing direct-expansion methods. Close- humidity, control cannot be maintained during the cooling season by the surface cooling type of equipment. Winter humidification. may be accomplished by use of evaporating pans or spray nozzles. The cooling coils serve no purpose during the intermediate or heating seasons, so in this-respect the spray type equipment is often preferred, in that during certain seasons evapora tive cooling will be sufficient to produce the cooling desired. Effective cooling and dehumidificatipn accomplished by surface Units are dependent ..inn many variable factors. The air velocity through the unit, air ditioned space directly. These booster fan equipments may use part by pass air as illustrated in Fig. 3 or 100 per cent dehumidified air and. reheaters. The main apparatus, in either case, may or may hot have a by-pass connection, depending on load conditions and other design factors. The systems illustrated in Figs. 1 and 2 may be converted into the surface cooling type by merely replacing the dehumidifiers with surface cooling coils which use cold water or direct expansion of refrigerant to accomplish the required cooling and dehumidifying. The coils may also be installed within the spray chamber, either in series with the sprays or below them. . DEHUMIDIFIERS Information on spray type dehuipidifiers is given in Chapter 11. Surface cooling type dehumidifiers generally consist of extended-surface coils within which the water or refrigerant is circulated or the refrigerant is expanded. The air to be cooled and dehumidified is drawn or blown over the coils. This system is generally comparatively low in initial cost and has low operating costs. Some localities have refrigeration codes ^Patents exist covering the use of the by-pass for cooling and dehumidifying systems. 170 temperature, moisture content of the air, water or refrigerant tempera ture, and velocity of the water or refrigerant through the tubes must be considered in selecting the proper unit for a given design load. If any of these factors vary without a corresponding variation of the other factors, the effective work of the coil will increase or decrease, asThe case may be. DESIGNING THE SYSTEM The. general procedure for the design of a..central cooling and de humidifying system is as follows: . ... : i 1. Calculate the heat gain for each room or space to be conditioned. (See Chapters 6 and 8.) . . 2. Establish the temperature of air leaving the supply inlets. . . 3. Calculate the quantity of air to be circulated. ' 4. Estimate the temperature loss in the duct system; , ; ' 5. Determine the volume of outside air to be introduced. (See Chapter 3.) 1 6. Calculate the heat to be removed by the cooling and dehumidifying apparatus'; 7. Calculate the size of the reheating equipment. . 8. Select cooling equipment and heating equipment from manufacturers' data and performance curves. . 9. Design the air distribution system and the air outlets and inlets. (See Chapters 19 and 20.) : . ,: ... ... 171 of andAmerican Society Heating: Ventilating Engineers Guide, 1936 .10. Calculate the total static pressure of the system. . 11. Select the fan, motor, and drive. (See Chapters 17 and 42.) 12. Select the pump and motor. : .....' : . 13. Design the control system. (See Chapter 14.) . . . - . - - zoning : " - `: . The above general outline of procedure will prove satisfactory for the smaller and less complex installations. However, when dealing with airr conditioning systems for large, buildings,, after a proper analysis has been made of the conditions,to be maintained and the heat loads encountered, it ;is generally considered best practice to divide the complete job into a number of suitably sized units. In some cases a unit per floor or group of Fig. 3. Central Dehumidifying Plant and Local Recirculating Fans .[ floors may complete the design satisfactorily, whereas in others it may be advantageous to have separate^ units'for each of the various outside exposures of the building. Where ^Ke floor area is large in relation to the outside wall exposure, it is obvious that provision must be made for the variable load to, which the. outsidle exposures are subjected. The heat lorids ori inside rooms are apt to be less variable since the fluctuations of the outside weather, conditions are riot directly involved. . Such conditions often result in the natural zoning or.segregation- of rooms having similar exposures and internal heat loads. Variation; ip the hours of occupancy in different pprtions of. a building also frequently require careful zoning for successful operation, ....... : .; . .. ; LOCATION OF APPARATUS ^ ... Availability, .of space-forc apparatus and duct work is of primary , im portance when selecting the type of system for a given design. Ip general, ' 172 . Chapter 9--Central Air Conditioning Systems ii. for large installations, the refrigeration eqiiiphierit, because of its size, weight, and operating characteristics,- is located in the basement along with the boilers, fire pumps, and other equipment. The air conditioning apparatus is generally located where clean outdoor air is readily available, the designer bearing in mind that supply and return air ducts, steam con nections, water and drain connections, and electrical connections must be made to the equipment proper. , \. TEMPERATURE OF AIR LEAVING INLETS In comfort conditioning applications, air has been distributed, from properly designed inlets without producing drafts at temperatures varying from approximately 5 to 30_ deg below the required room temperature. Factors influencing the design and selection of air inlets are: ceiling height, contour of ceiling, length of blow, and temperature and quantity of-air to be distributed. Most summer conditioning installations are designed to supply the air to the conditioned space at from 8 to 18 deg below room temperature. Recently the use of specially designed nozzles has indicated the possibility of reducing the air quantity necessary to dissipate a given heat load by introducing the air into the room as much as 30 deg below room temperature. Directional flow inlets which spread the air fanwise permit lower inlet temperatures than single direction inlets. Comfort conditioning systems employing differentials greater than 18 deg require special consideration and design experience because high pressure inlets or nozzles are usually used. Further, care must be taken to allow a sufficient air quantity under all load conditions, to insure good distribution. If winter heating, as well as summer conditioning, is to be accomplished by the same distributing system, the design of the inlets will be influenced as discussed in Chapter 22. Industrial systems in which drafts are not objectionable usually employ a temperature dif ferential equal to the dew-point depression. . AIR QUANTITY REQUIRED For calculating the quantity of air required to absorb a given heat gain the following approximate formulae may be used: ' M= Hs 60 X 0.24 X (t - ty) =dQ d) or, assuming a constant value of 0.075 lb for d, where S, X 55.2 Q = 60 X (< - h) (2) Q = volume of air required, cubic feet per minute. fls = total sensible heat gain, Btu per hour. t = room temperature, degrees Fahrenheit. . ty = inlet temperature, degrees Fahrenheit. . M = weight of air required, pounds per minute. : .` . ... d = density of air at the temperature and relative humidity of the rooni, pounds per cubic foot. ... - . . Example 1. The total sensible heat gain in a restaurant when held at 80. F is 199,736 Btu per hour. Assuming a 12 deg F temperature differential between the entering air and American Society of Heating and Ventilating Engineers Guide, 1936 the'room temperatures, which is the same as assuming the dry-bulb temperature of the entering air to be 68 F, calculate the required air capacity of the system. ' Solution. ' _ 199,736 X 55.2 ,, Q -- -------' -- ---- = 15,313 cfm = 1146 lb per minute. If a system similar to the one shown in Fig. 1 is used, 1146 lb per minute will .be the capacity of the dehumidifier as well as of the fan equipment. Example 2., If in addition to the 199,736 Btu per hour sensible heat load, the con ditioned space has a moisture gain of 384,000 grains per hour, calculate the apparatus dew point required to give maintained conditions of SO F dry-bulb and 65 F wet-bulb with a corresponding 56J^ F dew point. ' Solution. With 384,000 grains of moisture per hour to be picked up, the entering dew point temperature should be low enough so that the addition of this moisture will not increase the dew point above 56 F. Grains per pound of air saturated at 56J4 F (Table 5, Chapter 1) ' ' Less: Grains per pound to be picked up, ... / 384 000 ~li46~X 60' 68.0 5.6 Grains per pound allowable in entering air 62.4 This corresponds to an apparatus dew-point temperature of 54.17 F. Example S. Illustration of the by-pass system. (See. Fig. 2.) .. . Assume the same data as for Example'2. Instead of passing all of the air through the dehumidifier for cooling and dehumidifying, a portion may be passed through and the balance be mixed with the conditioned air at the leaving end of the dehumidifier, the mixture being proportioned so that the resultant conditions will be those required to give proper conditions in the area considered. `' Solution. The quantity of air to be dehumidified, the quantity to be by-passed, and the apparatus dew-point temperature may be approximately calculated as follows: Let ... * = percentage of air to be by-passed. Y = percentage of air to be passed through the dehumidifier. Id = apparatus dew-point temperature, degrees Fahrenheit. . The quantity X of 80-F air must .mix with the quantity Y of dehumidified air to produce air with a resultant 68 F dry-bulb temperature. Also, X quantity of air at 56F dew point must be mixed with Y quantity of dehumidified air to give a resultant dew-point temperature of the' mixture of 54.17 F. It is assumed that the air passing through the dehumidifier is saturated. ' _ \. ' ' Solving simultaneous equations, 80.0* + Yta .= 68.00 56.5* + Fid = 54.17 23.5* + 0 = 13.83 (3) (4) 13.83 X 100 *= 23.5 59 per cent, air by-passed. Y = 100 -- * . = 41 per cent, air passed through washer. The second step is to determine the apparatus dew-point temperature. Substitute * in either Equation 3 or Equations, and solve for t&: 80 X 0.59 + td X 0.41 td = 68-47 0.41 68 51.2 F, the apparatus dew point. 174 - . 9--Central. Air Conditioning Systems t . HEAT to be removed by cooling and dehumidifying apparatus ,, 'jj. / Assume the same data as for Example 3. If the amount of outside air, at hulb and 75 F wet-bulb, required for ventilation has been found to Be 169 lb 9p5erSmoliuntuio'tne., ' the refrigeration capacity required. determine AsthtTheUtog tal wedigehUt omf''dthifeiear'irthinetrot0dtuacleTMd orker >e donei TMiacy'.b. iacod,mpu^r ALeirssp:asOsiuntgsitdheroauirghlodr evheunmtiliadtiifoienr, 1_146 X 0'41...................................... 470 l,b, - ------------:-------------- 1691b Return air......................-.................. The refrigeration required.for the:return air is;. Total heat per pound at 65 F....... ...................... Less: Total heat per pound at 51.2 F............. 301 lb 29.96 Btu 20.92 Btu 3R0e1qulbireXme9n.0t f4oBr ctuool=ing2712l1b Boftureptuerrnmaiinr.u__te___re__q_u_i_re__d_ t_o__c__o_o_ft_he 9.04 Btu return air, . . The refrigeration required for the outside air is: Total heat per pound of outside air............................______........... ... 38 46 Btu Less: Total heat per pound at 51.2 F............... :.......... ___ 2(192 Btu Requirement to cool 1 lb of outside air............................ .....j j7 54 gtu 169 lb X 17.54 Btu = 2964 Btu per minute required to cool the outside air. . Th2u7s2,1thBetuto-tFal2r9e6f4rigBetruat=ion56re8q5uBirteudpise:r minute, which is equiv. alent to a load of 28.4 tons of refrigeration. " SIZE OF REHEATERS A properly designed air-conditioning system will have reheaters of sufficient capacity to heat the conditioned air from the apparatus dew point temperature to the inlet delivery temperature. If winter heating is to be accomplished, consult Chapter 22. , The following general formula may be used to determine the amount of heat necessary to reheat a given quantity of air: Hi = 0.24 (ty - la) -fcf . ( wkere Hi -- heat to be supplied to reheater coil, Btu per hour. Example 6. Assume the same data as for Example 1, and find.tfie amount of reheating required. ' . Jf' Snliiliftn. SURFACE COOLING PROHLEM The amount of coil surface required for a given amount of work is dependent upon factors previously listed. Obviously, the various types of American Society of Heating and Ventilating Engineers Guide, 1936 surfaces made available by different manufacturers will have different transmission values. It is recommended that the designer consult the latest manufacturers' catalogs because more accurate ratings are being issued from time to time. 8 Water in ( N J ( .- Water out Air in 95 F dry* bulb 78 F wet-bulb - 50 F + 30 F=80 F Fig. 4. Counter-Flow Surface Cooling Diagram Example 6. It is desired to cool and dehumidify 30,000 cfm of air at 95 F dry-bulb co wet-bulb, and 72 F dew point, to a 60. F dew point. Cooling water is available at 50 F in a quantity which will allow a 30 F rise in temperature to be used.' The counter now surface cooling used is sketched in Fig. 4. Solution. The pounds of partially saturated air cooled and dehumidified per hour equal 60 times the cubic feet of air at 95 F dry-bulb and 78 F wet-bulb brought past the coil surface per minute, multiplied by the pounds per cubic foot of the air as determined from Table 3, Chapter l. .. ;. 30,000 X 60 X 0.0708 = 127,440 lb per hour. . The total heat Ht to be removed per hour by the surface coil is found to be equal to the pounds of partially saturated air passed over the coil per hour times the difference between the total heat of air at 78 F wet-bulb and at 60 F wet-bulb. Ht = 127,440 (41.42 26.37) .= 1,918,000 Btu per hour. The latent heat L to be removed per hour will be found by multiplying the pounds of partially saturated air passed over the coils per hour by the difference in the latent heat of the air per pound at the initial and final dew points. .: L = 127,440 (1091.6 - 1086.2) = 688,000 Btu per hour. . The sensible heat Hs to be removed per hour is equal to the total heat of the air less its latent heat. .. . Hb -- Ht -- 1,918,000 -- 688,000 = 1,230,000 Btu per hour. ' Manufacturers' standard ratings for surface coolers are usually based. on the cubic feet of air passed , through their equipment per minute, reduced to the conditions of saturated air measured at a temperature of 70 F. In the present example, to convert the 127,440 lb of air cooled per hour to a basis which will permit the use of such standard ratings, it is necessary to multiply the pounds of air cooled per hour-by the specific"' volume of the air, and to divide by 60. .. 127,440 X 13.68 . . . 60 . !_ 29,100 cfm of 70 F saturated air. The amount of cooling water necessary when a 30 deg rise in its temperature is to be used is: ' ' : : . .. v 1,918,000 .! Chapter 9--Central Air Conditioning Systems ... .c u linter flow of air and water, it is necessary to determine the With co" ture difference between the air and the water in order to mean rlyuse the transmission coefficients given in apparatus rating tables. ` "" tumnpMturfi difference =----------i=i-- /r*\ 10) Dl = the difference between the temperatures of inlet air andi outlet water, degrees X) = fhe^ difference between the temperatures of outlet air and inlet water, degrees * Fahrenheit. (95 -- 80) (bO 50) = 12 33 F , (95 -- 80) loge (60 - 507 If from apparatus rating tables based on air velocities over the coils and water velocities through the coils, it has been found that the transmission coefficient is equal to 8.0 Btu per square foot per degree difference in mean temperature between the air and the water, the area of cooling coil surface necessary will be equal to the sensible heat divided by the trans mission coefficient and also by the mean temperature difference. - 1,230,OUu _ jo 450 square feet of cooling coil surface necessary. 8.0 X 12.33 ' The latent heat is taken out at the same time the sensible heat is extracted, but no extra surface is required unless the latent Heat exceeds approximately 40 per cent of the total heat. This is because the wetted surface has a much higher coefficient of transmission. Approximately 10 per cent more surface should be added, if the latent heat exceeds 40 per cent of the total heat. .. . AUXILIARY EQUIPMENT Consult Chapters 14, 17, 19, 20, 22, and 42 for information on the air distribution system; air outlets and inlets; static pressure on fan; fans; motor and drive; and the control system. . PROBLEMS IN PRACTICE 11 1 What is meant by the term evaporative cooling? Evaporative cooling, or adiabatic saturation of the air, is only effective when the air to be cooled is very dry. It is accomplished by passing the air in an unsaturated condition through a water spray which evaporates a part of the water at the expense of the sensible heat. In this adiabatic transfer the total ,heat content of the air remains constant while the dew point rises and the drybulb falls until the air is saturated. . 2 # In summer air conditioning what factors control the difference between the dry-bulb temperature of the conditioned space and the dry-bulb tem perature of the entering air? ' , , '' .. 1. The duct and supply grille arrangement permitted by architectural and structural requirements for the particular space, e.g., ceiling height and obstructions on ceilings, such as beams. . . . 2. The state of activity of the occupants. > 3. The velocity at the inlet grille, as limited by noise level requirements. . .; 177 1936American Society of Heating and Ventilating Engineers Guide, 4. The direction of the jet relative to the occupants. 5. In some cases, the temperature of the available water supply, which may have some bearing on the air delivery temperature. .. me 3 9 What factors determine the volume of conditioned air which must be delivered to the space? The sensible heat to be removed, and the allowable temperature differential. 4 9 What factors determine the dew point of the air entering the space? The maximum dew point desired in the conditioned space, arid the moisture gain in the space per unit weight of air supplied. :' 5 9 Why must the air leaving a dehumidifying type air washer be reheated before delivery? .- The air leaves the dehumidifying air washer saturated at a relatively low temperature which in most cases is lower than the allowable delivery dry-bulb temperature. Also the air may possibly, be carrying a small amount of entrained water which might settle out in the ducts near the washer and cause corrosion difficulties. . 6 9 What methods are used for reheating air? 1. Passing it over reheating coils. 2. Mixing it with by-passed air at a higher temperature. .. 7 9 What determines the final temperature of the spray water in a dehumidifier? Because of the effectiveness of the'heat transfer between air and finely divided spray water in a well designed dehumidifier, the air will be cooled to within 1 or 2 F of the final water temperature, provided the air velocity through the washer does not exceed 600 fpm. This final temperature should then, be taken as 1 or 2 F lower than the required dew point of the air leaving the washer. > 8 9 What are the advantages of using counter flow of air and water in surface coolers? . Counter flow results in a higher mean temperature difference than does parallel flow for the same range of air and water temperatures, which means that less cooling surface is required. Counter flow permits higher initial water temperatures and also allows a greater temperature rise for the water. These factors combine to reduce the cost of circulating and refrigerating the.cooling water. , . 9 9 What factors other.than cost should be considered in determining whether to use a central system or another type? * a. Appearance: The equipment must be designed to harmonize with the architecture of the building. b. Distribution: The system must- maintain adequate and uniform air motion over the entire conditioned space. . \ , c. Control: The control system must be designed to give effective partial load operation. 10 9 Can the central cooling and dehumidifying system be used as an all-year- round conditioner? . By modifying the control system and adding blast coils or a water heater to the spray type system, the cooling system will function as one for heating and humidifying. The surface cooling type may be transformed by modifying the control, and adding another set of coils and a humidifier. .11 11 9 Will the tons of refrigeration-effect per day be the value calculated in Example 4 of this chapter times the hours of operation? ' No. The tons of refrigeration-effect are functions of the load. The components of the load vary, that is, the number of people occupying the space, the outdoor conditions, and the solar radiation will change from hour to hour and from day to day. The calculated load represents the maximum required for design peak conditions. 178 . Chapter 10 COOLING METHODS Methods of Cooling Air, Evaporative Cooling, Dehumidification, Silica Gel System, Alumina System, Lithium Chloride System, Design of System, Operating Methods, Steam Jet System, Centri fugal Compression Systems, Compressors, Refrigerants, Methods J of Cooling, Condensers BY using any of the following four methods, or any combination of them, effective temperature (see Chapter 3) may be reduced. o Sensible cooling: Lowering of the dry-bulb temperature by the removal of sensible heat without change of the dew-point temperature. b. Dehumidifying: Lowering of the dewrpoint temperature by the removal of mois ture without change of the dry-bulb temperature. c. Evaporative cooling: Lowering of the dry-bulb temperature through the evapor ation of moisture without the addition or the subtraction of heat. d. Air motion: Increasing the air motion over, the body. As an example, let the condition be considered of 92 F dry-bulb, with a 40 per cent relative humidity, corresponding to a wet-bulb temperature of 72.8 F, and an effective temperature for still air of 81.1 F. This effective temperature may be reduced 3.1 F by any of the four basic methods mentioned, as follows: :. First, by lowering the dry-bulb temperature to 85.5 F without changing the dew-point of 64.2; this gives an effective temperature of 78 F. Second, by reducing the moisture content of the air to 46 grains per pound of dry air without changing the dry-bulb temperature; this gives an effective temperature of 78 F. Third, by reducing the dry-bulb temperature to 83.8 F without changing the total heat of the air. This requires the evaporation of 14 grains of moisture per pound of dry air, and the effective temperature will become 78 F. . Fourth, by increasing the air movement from still air to 460 fpm, a velocity which will reduce the effective temperature 3.1 F from 81.1 F to 78 F. Method to Employ The best method of reducing the effective temperature in any specific case will depend on the accompanying circumstances and can be deter mined only by a thorough analysis made by a competent engineer. Generally speaking, the removal from the air of the sensible heat, or moisture, or both, by sensible cooling or dehumidifying is the most satisfactory method. Adequate results by the utilization of air motion or by evaporative cooling are difficult to obtain because of the dependence of both methods upon climatic conditions beyond the engineers' control although these methods, are much less expensive than the first two 179 American Society of Heating and Ventilating Engineers Guide, 1936 State Table 1. Average Maximum Water Main Temperatures3 ClTT Temp. F State City Temp, p Ala.... Ariz... Calif.. Colo... Conn.. D. C.. Del.... Fla..... Ga .. in.,..;. Ind.: lowa:Kans.. ky;.;. La....... Me..... Md.:... . Burmingham............ 84 Mobile........................ 73 . Phoenix.................. 81 Tucson....................... 80 . Anaheim.................... 60 Berkeley.................... 69 Fresno........................ 72 Fullerton........ .......... 75 Glendale.............. . 68 Los Angeles............... 75 Oakland.........:............ 69 Ontario........................ 70 Pasadena..... ............. 82 Pomona..................... 75 Riverside.................... 78 Sacramento............... 72 San Bernardino.....___ . 65 Minn~....... San Diego....;!......;..... 82 " San Francisco.:......... 62 Whittier.................. . Denver..................... 75 75 . Bridgeport................. 66 St. Joseph:... ......... . Hartford--'........ ......... 73 ; New Haven............... 76 Waterbury................. 72 Nehr. . Washington..............- 84 Omaha................!..... Wilmington............... 83 Nev.. ....... Jacksonville.;................... Miami .................................... 80 80 n. h:. .. N. J................... -Tampa........................ 77' - Atlanta................................... .. . 87 : Macon...............................;..... 80 Chicago..................................... Cicero........................................... Evanston................................ 76 76 73 N. Y................ Albany.................... * Buffalo ................. ..................... Peoria........................................... 67 Rockford...:.......;....;^ 59 Springfield....;................... 82: Evansville.................. . Gary....i--......_____ I ndianapolis.--i._. South BendL.;.'.,,........1. l erre Haute.................... 86 . .75- : 80 . . , 61 .82 '" Rochester................. :...... Schenectady.................. , Syracuse...:............... :...... Utica....:,..--............... . Cedar Rapids...... ........ . Des Moines..................... 78. .. . N. C.............. Asheville. I........................... 77- Sioux City....:. . 62 57 N. M. Kansas City........................ . Topeka................... . Wichita.^.,,.......1........ 86 Ohio............ 88 Canton................ .... 72' . ' Cincinnati............ :... Baton Rouge 85 . 85 Cleveland Columbus.,..........L. -Dayton....... Augusta...:............ ;.. 60 Lakewood__............. Baltimore............... . ,. . 67 , Toledo'--........... 80 70 76 50 68 70 68 76 77 70 84 77 53 64 56 82 55 . 80 77 82 . 84 84 85 70 87 87' 61 76 ' 63 74 ' 78 79 68 75 56 74 75 72 70 : 60 74 . 69 . 70 . 74 85 82 65 76 50 84 74 82 60 82 72' 83 - "These averages taken from various city water main locations, with some actual values slightly higher and some lower than values shown. -. . : ; . ; - :: 180 Chapter IO^Cooling Methods R. I -- s. c.... S. Dak. Tenn... Texas._ 1 Average Maximum Water Main Temperature3 (Continued) Crrr Temp. F ` ' Stato ., ' . ClTT' Temp. F Oklahoma City.. Tulsa-------------Eugene'......... -..... Portland!............. Altoona--..... ,..... Erie................. -- Johnstown.......... McKeesport....... Philadelphia....... Pittsburgh.......... Providence........Charleston.......... Greenville........... Spartanburg--.. Rapid City-...... Chattanooga...... Knoxville........ Memphis-----Nashville.--..... Amarillo.............. Austin....... :......... Beaumont--........ Dallas-------------Fort Worth........ Galveston--..... ... Houston........ Port Arthur..-- San Antonio--.... Wichita Falls-- 82 .85, 60 64 . 74 75 74 82 83 67 68 80 81 78 55 84: 89 70 90 65 90 86 86 84 90 84 83 76 85: 44 - Salt Lake City______ . 60': Va.............. ; Fredericksburg_____ 75. ' Lynchburg................ . 73 Norfolk........................ 80 58 Seattle. ....... ~______ 62 Spokane...................... 51 Tacoma. .................. 57 W. Va_____ Charleston........... 85 - Huntington......... 78 Wheeling-- __-_____ 78 Wis..... 54 58' . Milwaukee...... ..... 1--. : 70 Racine..........j........ ,;k -.68. Phovtnce Alta.;.;........ Calgary................. B. C... . Toronto...... ................ P. E. I........ Charlottetown...::..... 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. .... ... . - mentioned. Cooling by evaporation is satisfactory only when thie air to, be cooled is very dry; air motion as a means of producing cooling effect is never entirely adequate in the range of high, temperatures. Of the two, evaporative cooling, or adiabatic saturation of the air, is a much more, dependable method which will make more reduction in the effective temperature than will an increasing, air motion within permissible limits. As an example .of this, consider, an outdoor condition of 96 F dry-bulb; and 80 F wet-bulb. The effective temperature is. 85.7 F and, if the . still; air is moved,with a velocity of 300fprii, the' effective temperature- will be. reduced only 2.0 F while saturation at the .wet-bulb temperature would reduce the effective temperaJure 5.7-F. At 300. fpm velocity this satu rated air would reduce the effective temperature to,75.6 F, thus making a, total improvement of 10.1 F. .i. . J , \ * .. - . .' - Frequently the temperature of the city water main, supply is.low' enough during the summer- to permit an appreciable cooling: effect,:r Table 1 lists the maximum city water main temperatures for various- localities in this country and Canada.. Evaporative Cooling '' ....... ' 1 .............. Evaporative- cooling is .accomplished ,t>y-passing,.air; .through a water 181' American Society of Heating and Ventilating Engineers Guide, 1936 spray in which the water is being continually recirculated; The air entering in an unsaturated condition, evaporates a piart of the water at the expense of the sensible heat. As this is an adiabatic transfer, the total heat content of the air remains constant, while the dew point rises and the dry-bulb falls until the air is saturated. A system1 of ducts and a propel ling, fan are used to distribute the air in a proper manner. It will be seen that the reduction in dry-bulb temperature is a direct function of the wet-bulb depression of the air entering the dehumidifier and that the resulting air temperature is governed entirely by the entering wet-bulb temperature of the outside air. Dehumidification .. . Dehumidification may be accomplished in three ways: 1. By cooling the air below the dew point ?nd causing a part of the moisture contained to precipitate. ' ' 2.: By extracting all or part of the moisture by absorption. 3. By extracting all or part of the moisture by adsorption. ' As used in this discussion, the term adsorption pertains to the action of a substance in condensing a gas or vapor and holding the condensate on its surface without any chahge in the chemical or physical structure of the substance and with the release of sensible heat. The term, absorption, implies a change in the chemical or physical structure of a substance in the process of dehydrating air. Adsorption is distinctly a surface action and is thereby distinct from absorption. Adsorbers include lithium chloride, calcium chloride; silica gel, lamisilite, or any of the halides; absorbers include sulphuric acid. ........... Dehumidification by Refrigeration ' ' . Air conditioning imposes requirements on refrigeration equipment not usually found in general cooling work, so that specially designed apparatus is often needed to replace that normally used for industrial cooling. Standard equipment can be adapted to meet air conditioning require ments but extreme care must be taken to determine the limits of its applicability. . .` . In industrial or process cooling systems the load is fairly constant, noise in operation is not of paramount' importance, space is available or rela tively cheap, condenser water is not a source of worry, and the cooling system is to a great extent separate and independent of other mechanical equipment. By contrast, air conditioning, especially as used for space cooling and comfort work in office buildings, theaters, and places where people gather requires special consideration of all these factors. Space in public buildings is limited and condenser water is expensive. Noise interferes with the occupants, and the cooling equipment must dovetail with the other air-handling apparatus. Most important, the load fluctu ates tremendously and is seasonal. - ' A complete discussion of the thermodynamic problems of refrigeration is given in Chapter 2 on Refrigeration. ISee Air Washer Performance in Chapter 11; also Theory of Atmospheric Codling iii same chapter. 182 Silica Gel System ... . Silica gel is a chemical composition made from sodium silicate and add, the chemical formula being Si02. It has an appearance greatly resembling that of clear quartz sand but it differs in structure in that the crystals are highly porous, with voids constituting 41 per cent by volume although the pores are microscopic in size. This material possesses the property of being able to adsorb a substantial portion (about 25 per cent of its own weight) of moisture from the air without any increase in its volume. After die silica gel has become "saturated" or has adsorbed moisture to the limit of its capacity, the moisture may be driven from it; by the application of heat, again without change in the structure,- volume, or chemical composition of the silica gel. This cycle may be repeated in definitely. When applied to air conditioning the silica gel which is exposed to the air reduces the moisture content in the air and releases sensible heat which may be readily removed from the air. A typical diagram of this system is shown in Fig. 10, of Chapter 2 on Refrigeration. . Practical Application of Silica Gel . ". ; Silica gel has two applications when used to replace refrigeration. In the one principally used, the air from which moisture is to be extracted is taken through silica gel beds by suction or pressure fans, and by means of this process the moisture becomes adsorbed by the silica gel and the air leaves at a lower dew point and a higher sensible temperature than those at which it entered. If this air is passed over surface coolers in which tap water or another cooling medium is flowing through tubes, a certain amount of sensible heat will be removed. The air leaves the surface cooler or interchanger with the same dew point with which it emerged from the silica gel beds, but with a lower dry-bulb temperature, although the drybulb temperature may be higher than the temperature of the air entering the silica gel beds. In another method, the first two of the steps, outlined are duplicated, and in addition the air is carried through a spray type washer. Because the air enters the washer with a low wet-bulb, and because adiabatic saturation will take place at a temperature close .to the entering wet-bulb, considerable cooling of the air can be accomplished; but this can be done only with a consequent increase of the dew point. . It is necessary to reactivate the silica gel after it has adsorbed about 25 per cent of its own weight in the form of moisture. As reactivation requires a high temperature and since silica gel is only active-at low tem peratures, cooling of the beds must also be completed before they can be used again. This necessitates three stages in the silica gel containers and requires either three beds of silica gel or one bed divided and automatically put in position. The reactivation is usually done by means of gas or oil fires and the cooling of the beds by means of indirect water cooling or by means of small quantities of dehydrated air taken from the system beyond the interchanger. Alumina System of Adsorption Activated alumina contains a trifle over 91 per cent of aluminum oxide, AltOt, which material will adsorb nearly 100 per cent of the-vapor in the of andAmerican Society Heating Ventilating Engineers Guide, 1936 i air up to about 8 or 10 per cent of the weight of the adsorbing material after which the adsorption falls off gradually as the saturation point is approached. The application is quite similar to that employed for silica gel; that is, the material is exposed to the air flow and after reaching about 75 per cent saturation is reactivated by removing the moisture adsorbed by means of applied heat. The actual scheme generally f0j_ lowed in the use of this material for continuous service varies somewhat from silica gel inasmuch as the material is placed in three units which are used consecutively for the different steps. These steps permit each unit . to operate as follows: . a. In series with the preceding unit. b. Alone. c. In series with the following unit. . . % % $ 1 i This plan allows for adsorption, reactivation, and cooling, in a manner t similar to that used with silica gel. ... ! Taking a single unit, when it is in the o step and operating with the I preceding unit, the alumina adsorbs approximately. 25 per cent, of the t moisture in the air and takes up about 1.3 per cent of its weight of water. I During the second step when it is operating alone, it takes up 100 per cent of the moisture in the air until the weight of the water adsorbed is brought up to about 6.7 per cent. During the third step when the unit is operating 1 with the succeeding unit, it extracts about 75 per cent of the moisture in the air until the water weight adsorbed comes up to about 10 per cent of the weight of the adsorber. 'The time allowable for reactivating is equal to the time occupied by the second unit adsorbing alone, plus the time when the second and third units are adsorbing in series, plus the time ! | | f t I I .when the third unit is adsorbing alone, at the expiration of which time the I -first unit will be again required. .. I The temperature of air used for alumina reactivation is usually between I 300 and 700 F and the air flow rate will have to be higher with the low temperature air than it will be with reactivating air of higher temperature. .For example, air at 400 F for reactivating will, at 10 cu ft per hour per pound of alumina, require about 6 hours for reactivation. In the .three . unit system, after reactivation the cooling of the activated alumina may .be carried out with considerable rapidity by using dry air from the adsorption unit for circulation through the unit which has just completed reactivation.: The final temperature of the unit before it goes back into service . . , , i | \ should be not over 200 F. As a basis fpr computing the amount of cooling .air required for reactivation, each.cubic foot of cooling air has been found ^capable of removing 2.2 Btu when heated from 85 to 200 F and of provid ing a sufficient margin of safety in operation^ . ../ ' . .Lithium Chloride Adsorption System . 1. ^ Practically all salt solutions have the property of: adsorbing or con densing moisture from a gas. The amount depends on the character of the solution, its gravity',' temperature and viscosity. One.'of the best known dehydraters, calcium chloride, for instance, has been long known for this property. Its characteristics, however, present a limiting factor of about 30 per cent relative humidity, so that the resultant dew point of air-brought in intimate contact with calcium chloride is usually, too.high for comfort work without further refrigeration. - 184 ; J 1 Chapter 10--Cooling Methods , of solid dehydraters or adsorbers and liquid adsorbers are funTdhaemeeynet*al y he same a diagram of a lithium. chloride adsorptio. n evstem is shown in rig. l. .. ymL linuid adsorber is brought in contact with air having a certain 111 nressure due to the moisture of water vapor that is in it, and the VuPvIp either sodium, lithium, calcium, or whatever is used, having a chlonae, . adsorbs moisture in the form of water from the Tr vaoor that is in the contacting air.' Thermodynamically, it is Tfi-relv oossible to.measure this change and to know definitely that a dennireiy y-^ takes place because of the fact that there is a definite rise remDerature in the liquid adsorbing the moisture, which is definitely a . function of the amount of water vapor condensed from the air stream. Conditioned air Dry bulb dependent upon cooling medium 58 D. P Recirculated {liquid 82 - , '. ' .. Refrigerated or city Water recooler p 1Dehumidified A.-- air \90D. B. / 69 W. B. S 58 D. P. ^Liquid distributor Liquid adsorber unit' Liquid in tank 89 Regenerated liquid 1002 Unconditioned air inlet ^ Inlet Cooling water (city supply or cooling tower) Liquid to recirculated Liquid distributor Regenerator Of course, the liquid adsorber, contrary to the solid adsorber such as silica gel, takes on two functions: one, as an adsorber, and that adsorp tion, as has been stated, tends to create a rise in temperature; on the other hand, the mass of liquid in the adsorber tends to keep down the rise in temperature, so that by cooling the adsorber below a certain tem perature, a definite temperature can be maintained in both the liquid arid the air, which is a function of the heat balance between the total heat of the air and the total heat of the liquid. Adsorption of moisture by a liquid adsorber weakens the concentration of the liquid so that its adsorbing capacity is reduced and regeneration, or the driving off of the excess moisture in the liquid, must be performed, just as the driving off of the liquid adsorbed by a solid adsorber must be accomplished. However, with a liquid adsorber a very definite condition can be maintained; that is, a condition of density, by continuously with1 drawing a certain small portion of the total liquid for intensive con centration and the concentrated liquid added to the mass Of the liquid continuously, without varying to any marked degree the vapor pressure 185 of andAmerican Society Heating Ventilating Engineers Guide, 1933 of the total mass. This method of continuous regeneration and re concentration tends to hold the relative humidity of the leaving air always at a very definite point. . There are two methods of regeneration. One is the boiling of the excess moisture by raising the temperature of the adsorbing liquid to above the boiling point of the particular concentration. As the salt in the solution does not vaporize, it is not carried off in the boiling process The only care required is that in the small amounts of liquid diverted to the regenerator for concentration, too much moisture is not driven off occasioning freezing or solidification of the salts, or solids. '' The second method of regeneration which lends itself particularly well to ordinary low pressure heating systems, where steam pressure of about il . 12 lb per sq in., corresponding to a temperature of 242 F, is to raise the temperature of solution with ordinary steam coil interchangers to about 225 F, and then to pass the solution at this temperature over various types of scrubbers, over which ordinary air is passed. The increase in temperature of the liquid adsorber tends to increase its vapor pressure to such an extent that there is an exchange of vapor between the liquid adsorber and the air, as well as an equalization of temperature between the air and the liquid adsorber, so that the air is capable of taking up part of the moisture from the liquid adsorber to increase its density and to carry this excess moisture out into the atmosphere with the leaving air. After this vaporation has taken place, the highly concentrated, hot liquid adsorber is taken through an interchanger through which the water used in cooling the main solution can be re-used to reduce the temperature of the concentrated solution to a point where it may be thrown back into the main solution tank at a slightly higher temperature than the main body of the solution. As approximately only 10 per cent of the solution is regenerated continuously, a difference of 5 to 10 F in the concentrating solution only creates a rise of 1 F or less in the main body of the adsorber, so that its effect on increasing the temperature of the air to be dried is negligible. V1 As can be seen, there are two conditions of continuous operation which have a tendency to raise the temperature of the liquid. One .is the adsorption of vapor from the air, which, through a change of state, changes the latent heat of the vapor adsorbed to sensible heat, to raise the temperature of the liquid and consequently, the temperature of the air; secondly, the necessary heat added to the regenerator liquid in order to reevaporate and carry off the excess moisture which has been condensed in the first stage. In the regeneration process, the air currents in this, method have a tendency to carry away the excess heat of evaporation. In the first stage, that is, the main stage of adsorption, the .temperature of the main body of liquid is continuously cooled, and the excess heat carried away by some type of interchanger, through one part of which either cooling tower or city water is utilized. Of course, this water may be refrigerated, but under most conditions that is unessential. With the ordinary liquid interchanger, using cooling tower water, the maintained condition of the liquid and the air can be kept at a point very close to the prevailing wet-bulb, possibly within 5 F, and certainly within 10 F. s. i 1 s186 Chapter 10--Cooling Methods Design of System designing air conditioning systems, the capacity of equipment is j Jwfine apparatus of sufficient size to maintain predetermined decided y and humidities in treated spaces when arbitrarily estab- rei?Pd maximum atmospheric temperatures occur coincident with given "jvmnc of population, lighting, and power consumption. These factors a?rmine the maximum duty of the cooling system. The duty does not dCtearilv determine the size or capacity of the refrigeration apparatus. Sfrieerating capacity is expressed in tons, each ton being equal to the V^rotion of the heat given up by one ton of ice at 32 F melting to water t 32 F in 24 hours. This is equivalent to heat absorption at a rate of approximately 200 Btu per minute, or 12,000 Btu per hour. After the maximum duty is determined, the other factors concerning th^installation must be investigated. The total heat to be removed by the cooling system has many sources, some substantially constant and ethers extremely variable. These sources can be roughly classified as follows the first column indicating the order in amount and the second _____-In- In variflhilltV! 1. Fresh air supplied. 2. Population. ,. ^ . 3. Transmission through the structure. 4. Light and power consumed. 1. Fresh air supplied. 2. Transmission through the structure. 3. Light and power consumed. 4. Population. By combining these two columns, a third grouping is obtained as follows: 1. Fresh air supplied. 2. Transmission through the structure. 3. Population. . 4. Light and power consumed. In this last arrangement, the first two items are governed by atmos pheric conditions and they are therefore subject to tremendous fluctu ations in value. As they generally form 40 to 60 per cent of the entire maximum load, the duty of the cooling system will be much less than maximum most of the time. '. The transmission through the structure is especially influenced by the sun. (See Chapter 8.) In many cases, because of the heat flow resistance of the structure, the heat from the sun is retarded until it is compensated for by a reduced general temperature out-of-doors. A survey of Weather Bureau records indicates that maximum tempera tures occur less than 5 per cent of the cooling period and also that the duration of. peak conditions is never more than three or four hours. Two factors control the size of the refrigeration system, the evaporator or suction temperature, and the condenser or head temperature. With the knowledge that the system will operate most of the time with a load of not over 60 per cent of maximum, and that maximum demands will occur infrequently and only for short periods, some provision must be made to insure economical operation under-average conditions. This can be done by overloading the machine under extreme demands and basing the design on normal or average loads. Flexibility in arrangement can be provided in several ways. ' Variations in load change the efficiency of any machine and a refrigera ting system can be costly and inefficient if improperly designed or operated. 187 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Fortu nately, the trouble can be concentrated in the compressor and the problem relieved of many complications. It is comparatively easy to furnish condensers and evaporators to carry the maximum load so arranged that they will function properly at small demands. They affect the compressor performance to some extent but most of the compressor problems are in the machine itself. Variations in load are usually effected by lowering the suction tem- perature and pumping a larger volume of gas per ton through a greater pressure range. This is possible because the latent heat of the refrigerant remains nearly constant throughout the small range used and the specific volume varies rapidly with change in pressure. As the compressor must remove the refrigerant evaporated, the evaporator temperature fixes the displacement required. The objection to such method is that the total power consumed remains nearly constant and the power per unit of cooling increases rapidly as the total output is reduced. Such operation is satisfactory as long as the load is kept within 10 per cent of the rating of the compressor but this, condition does not commonly occur in air conditioning applications. 1 I' 3- I I ' I |: i; 5. I I: 4 1 | | f I I ^ Operating Methods. ` : a It is possible to divide the entire refrigeration system into a number of small units, which will allow cutting in and out of compressors and con- densers. as the load fluctuates. . f | | A second method of providing for economy of operation is to have I storage capacity which can be utilized during the peak period. A further I reference to the Weather Bureau records indicates that maximum con- | ditions prevail during the day for not more than three hours, and con- 1 : sequently the refrigerating system can be run for a longer period at I maximum efficiency with tanks to store cold water or brine for supple- " J menting the actual output of the refrigerating equipment when the load is f more than the machine will carry. This situation brings complications. | Storage tanks require space and extra apparatus, which increase the cost | ! of the entire system, and further, it is difficult to determine what the size ; of the compressor should be because of the other variables which enter the | . problem. Depending upon the availability of storage. space, the com- | i pressor could be designed for any reasonable percentage of the maximum 1 : load, so the smaller the compressor, the larger the storage space, and | ;. vice versa.' ' .' ; A third method is to provide in the compressor itself some means of reducing the capacity. This can be done by varying the speed and consequently the displacement of the compressor, or by varying the displacement, either by a partial by-pass of the cylinder or by a clearance pocket, in the head of the cylinder when reciprocating compressors areused. It might be assumed that the efficiency would remain practically constant. This is not correct, inasmuch as the machine friction remains; Constant with the by-pass or clearance pocket method and this raises thepower required per ton of refrigeration developed. Also, the volumetric efficiency of the machine falls'off rather rapidly'when-the clearance pocket or partial by-pass is used. By varying the speed of the compressor, the: efficiency of. the power, unit, falls, off as the speed is reduced, while the compressor friction remains constant.. .. ' ' : |' | I | I J I |, J' |' | V | 188 Chapter 10--Cooling Methods Another method of operation is the automatic starting and stopping of the refrigerating machine, with the automatic control designed to function as the load varies. :. . All of the methods described are used from time to time. . The methods of varying the output of a refrigeration system which have been outlined apply to the reciprocating type of compressor, although variations in the speed of the compressor to change the refrigerating output are common to all types of mechanical refrigeration. There is a further method of controlling the compressor output which is particularly adaptable to the centrifugal, type of machine. This is accom plished by varying the amount of condensing water used with the fluctu ation in demand load. Because of the characteristics of the centrifugal , type of apparatus, as the condensing water quantity is reduced and the condensing temperature consequently raised, the discharge pressure of the .centrifugal machine rises correspondingly and the horsepower input to the machine falls off. While this reduces the total power input to the . machine, it does not necessarily reduce the power, input per ton of re frigeration developed, as the power input does not drop'with a rising dis charge pressure as fast as the refrigerating effect produced drops. It is a method, however, which shows marked economies over the method generally used by the operating engineer, which is to lower the suction pressure in order to reduce the refrigerating output of the system. Steam Jet System So far the discussion has been confined to reciprocating, centrifugal, and rotary compressors. The steam jet type of compressor, under certain circumstances, is desirable for use in air conditioning. A complete flow, diagram of the system is shown in Fig. 4 of Chapter 2 on Refrigeration. The power used for compressing the refrigerant is steam, taken directly, from the boiler, thus eliminating the mechanical losses of manufacturing electric current. As the compression ratio between the evaporator and condenser under normal circumstances is large, the mechanical efficiencies of the equipment are somewhat lower than those of the positive mechanical type of compressor; also the condensing water requirements are con siderably 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, arid steam ejectors of the type commonly used in power plants for various processes will produce the necessary low absolute pressure to cause evaporation of the water. .. . In Chapter 2 on Refrigeration Fig. 4 shows a typical water cooling, application. The water to be cooled enters the evaporator and is cooled to a temperature corresponding to the vacuum maintained. Because of the high vacuum, a small amount of the water introduced in the evapor ator is flashed into steam, and 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 boilingpoint, determined by the vacuummaintained. The. amount of water flashed into steam is a small percentage of the total water circulated through the evaporator, amouritirig to approximately 11 lb-per Hour per ton of refrigeration developed.- i-The remainder of the water at the desired 189 American Society of Heating and Ventilating Engineers Guide, 1936~~~ 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 into the evaporator, plus any entrained air taken out of the water circulated, to a somewhat higher absolute pressure, and the vapor and air mix with the impelling steam on the discharge side of the jet. The total mixture of entrained air, evaporated water, and impelling steam is discharged into a surface condenser at a pressure which permits the available condensing medium to condense it. The resulting condensate is removed from the condenser by a small pump, from which it can be discharged to the sewer or returned to the system in the form of make-up water, or part of it may be returned to the boiler feed pump. As the normal temperature of water required for air conditioning purposes is between 40 F .and 50 F, with an average temperature of approximately 45 F, this type of water cooling is particularly desirable as the efficiencies and operating costs compare very favorably with other types of refrigerating equipment, especially in view of the fact that the cooling apparatus is, as a general rule, less expensive to install. Approximately three times as much condenser water is required for the steam jet cooling system as would be necessary with other types of mechanical refrigeration, but as the system can be designed with a large number of jets, each of which can be cut off as the load falls below maxi mum, constant refrigerating efficiency is maintained and frictional losses and volumetric inefficiencies are kept at a minimum.. - 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 small secondary condenser, of course, is necessary to condense the steam used in the secondary jet. ' Steam jet refrigeration has an advantage where cooling towers are used for supplying the condensing liquid, as there is a great saving in the amount of steam used per ton of refrigeration. As the outdoor weather conditions vary the load on the cooling system, the compression ratio between the condenser and evaporator can be reduced and less propelling steam need be used per ton of refrigeration developed. Roughly, in air conditioning work, mechanical compressors show .a falling off of 30 to 40 per cent in the power input when using the most economical arrangement of compressors, as the load varies from 100 per cent to 25 per cent-of the rated capacity; whereas with steam jet cooling equipment, the amount of steam required for producing the necessary refrigerating effect falls off in direct proportion to the load on the system. When steam refrigeration is em ployed with cooling towers, the efficiency increases as the output is reduced. Compressors and Refrigerants There are many different types of compressors, a number of refrigerants, different types of evaporators, condensers and arrangements of the cycle, and each type has its particular place and usage. The generally used compressors are of the following types: 1. Reciprocating compressors. 2. Centrifugal compressors. 3. Rotary compressors. 4. Steam jet compressors. _ , . 190 Chapter 10--Cooling Methods Ovtera-as llimefpficoiretnacnyt oat rtneequciuremmpeicnot ^a.s th--a--t t--he -w----h--o---l-e----u---n---i--t---r-equ--ire little 1 ration and make a minimum of noise. The noise level when the fan, ae"ys an<} compressor are in full operation should not exceed 25 decibels. H'trh compressor efficiency appears as an important factor only in the toiler industrial air conditioning systems. ., The refrigerants in most general use in commercial and industrial air conditioning are here listed in the order of their inoffensive odor charac teristics: i. Water vapor. . 2. Carbon dioxide.' . 3. Dichlorodifluoromethane. 4 Dichloromethane, sometimes called methylene chloride. 5. Methyl chloride. 6. Ammonia. 7. Sulphur dioxide. ' ', ' \ ' '. ' The various types of compressors bear varied relationships to the refrigerants used in both commercial and industrial air conditioning. Reciprocating compressors are generally used for any of the refrigerants listed except water vapor, dichloromethane, or other low pressure refri gerant, and they are used in both commercial and domestic air conditioning systems. They have been developed to a point where their efficiency is high and their operation very satisfactory. Relatively low speed opera tion makes them desirable for general use in large installations. They are of two types, vertical and horizontal, either single or double acting. The horizontal double-acting compressor is not generally used in air condition ing except when carbon dioxide is used as the refrigerant in. the larger industrial systems. Vertical, single-acting, encased crank, reciprocating * compressors of the uniflow type with valves in the pistons have proven reliable and are used in capacities from 1 hp to more than 100 hp. Re ciprocating compressors can be used with more refrigerants than other types of compression units. For instance, when carbon dioxide is used as the refrigerant, a reciprocating compressor is required because of the extremely high pressures and the relatively high ratio of compression. The production of refrigeration at temperature levels from 25 F to 55 F for general air conditioning involves special types of refrigerating compressors. Among these are: 1. Centrifugal compressors using a volatile refrigerant.' ' 2. Centrifugal compressors using water as a refrigerant. 3. Steam jet or vacuum systems using water as a refrigerant. 4. Rotary compressors using a volatile refrigerant. . - The first two types, centrifugal compressors, using dichloromethane or water vapor, can theoretically be used with any of the other refrigerants, but the resulting loss in efficiency with the higher pressure gases limits the centrifugal compressor to the two refrigerants named. At the present time the centrifugal compressors are limited to air conditiong systems of a minimum of 50 tons and more. Centrifugal compressors are usually built in two or more stages where the compression ratio is high, and their 191 X' of andAmerican Society Heating Ventilating Engineers Guide, 1936 design follows closely that of any other centrifugal equipment, such as general service pumps and fans. Steam jet compressors which have recently entered the field are simple and compact and, having no moving parts, they produce practically no vibration but are not economical for water temperatures much below 40 F or where the cost of generating steam is higher than the cost of operation with other prime movers.: . - Rotary compressors are generally used for methyl chloride and dichlorodifluoromethane because of their relatively low pressure and compression ratios. These compressors find widest use for fractional tonnage duty. The source of condensing water to some extent governs the type of refrigerant used. If condensing water is available at temperatures of not more than 70 to 75 F any of the refrigerants'mentioned can be used economically, but if the available condensing water temperature is above 80 F, carbon dioxide becomes uneconomical as its critical temperature is approximately 88 F. A condensing water temperature over 80 F makes the power required for compression high. All refrigerants have critical temperatures and pressures sufficiently high so that their efficiency is not materially affected by the condensing water temperatures, except in so far as this temperature affects the compression ratio. Steam jet cooling systems can use Water up to 85 F, or even slightly warmer. The applicability of the various refrigerants is interesting. Carbon dioxide is limited by the condensing water temperature; the power con sumption is slightly higher than that of other refrigerants; and the pres sures are three to four times that of ammonia. - The condenser pressures of methyl chloride and dichlorodifluromethane are approximately orie-half that of ammonia. Ammonia, probably the best known refrigerant, has the disadvantage of being toxic, and under certain circumstances explosive, corrosive, and irritating, even in small'quantities in the atmosphere. Ammonia is used exclusively in the larger indirect or brine cooling air conditioning systems. Sulphur dioxide is corrosive and irritating even in small quantities in the atmosphere and it is toxic Under certain circumstances. . Dichloromethane operates at pressures below that of the atmosphere, and it is to some extent toxic. Dichlorodifluromethane under normal circumstances is non-toxic, non irritating, and non-explosive, but under high temperatures it breaks down into several obnoxious, poisonous components. . Methyl chloride, under certain conditions, is explosive and slightly toxic. .. . - . The steam ejector water vapor system has none of the disadvantages of toxicity, explosiveness and corrosiveness encountered in the other refri gerants, but the system operates at less than atmospheric pressure. This, however, is not an important factor as there are no moving parts in the compressor and the possibility of inleakage of air is remote as all, of the equipment can be welded air and water tight.. The supply of-water is inexhaustible, and as a refrigerant, the make-up cost is negligible. The same boiler equipment can be used for heating in winter and for cooling in summer. . 192 Chapter 10- -Cooling Methods Electric Motors . ' Th motors used for driving compressors can be roughly classified in 1 * "e roups: synchronous, multispeed, or variable speed. Further infor- ^ on motors and their controls may be found in Chapter 42. Coolers The types of coolers used in connection with air.conditioning work fall ; . three general groups. The first is the direct cooling of water; the. xn.COnd direct cooling of air; and the third, cooling.of brine for circulation' ?n a dosed system, which can cool either water or air. One method of the direct cooling of water is to install direct expansion coils in the spray chamber so that the water sprayed into the air comes in direct contact with the cooling coils. Another common and efficient method of cooling spray water is to use a Baudelot type of heat absorber where the water flows over direct expansion coils at a rate sufficiently high to give efficient heat transfer from water to refrigerant. : Another type of spray water cooler is the shell and, tube heat exchanger, in which the refrigerant is expanded into a shell enclosing the tubes through which the water flows. The velocity of the water in the tubes affects the rate of heat transfer, and as the refrigerant is in the shell com pletely 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 temperature or the. temperature in the evaporator drops and there is a possibility of freezing the water in the tubes, which, of course, might split the tubes and allow! the refrigerant to escape into the water passage. This danger can be eliminated by automatic safety devices. Another system of cooling spray water is to submerge coils in the spray collecting tank, or in a separate tank used for storage. The heat trans mission 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; 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 fox' 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. . The indirect cooler, where brine ,is cooled by the refrigerant and the resulting cold brine is used to cool either air or water, introduces several other considerations. It is riot the most eeonoihical from a .power^con sumption 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,.but there are other considerations which make such a systerri desirable; In the first place, where a toxic refrigerant,is undesirable or cannot be used'due to fire or other risks especially in densely populated areas, the brine;can be 193 of andAmerican Society Heating Ventilating Engineers Guide, 1936 cooled in an isolated room or building and then be circulated through the air conditioning equipment in perfect safety because it is used to cool the water or air, without any possibility of direct contact between the air'and refrigerant. When an indirect system of cooling is used, it will be found that the heat transfer rate of the water cooler is considerably higher as a general rule than that of a direct expansion cooler for the same requirements. With direct expansion interchangers, it is almost impossible to keep the entire system flooded with liquid, whereas with brine interchangers the cooling medium completely fills the space of the interchanger and perfect contact is insured. '. ,. Ice may be used for chilling water or air. for conditioning work. Its application is limited because of the cost of ice, and the difficulty of handling it. The word "water cooling" is used advisedly in that the direct cooling.of air by ice is, while not impossible, rather impractical. It might be said that ice coolers are economical for systems requiring a maximum of 20 tons per 24 hours where the load fluctuates considerably, and where ice is introduced only as it is required to cool water. The most general method of cooling water with ice is to spray the water over the surface of the ice, insuring as much contact as possible and approximating the same performance as the Baudelot type of cooler. Because of thelarge fluctuations in joad in the air conditioning system, the higher cost of refrigerating effect when ice is used is offset by . the fact that there are no motor and condenser inefficiencies under partial load. Also, because the cost of the mechanical refrigeration equipment for the small system is so much higher per unit of effect, the fixed charges are small enough to overbalance the extra cost of the ice. 1 i \ > i J j : ( j . Condensers Condensers are usually either the double pipe type or the shell and tube type. Shell and tube condensers are almost identical with coolers. Double pipe condensers are arranged so that water passes through the inner of two concentric pipes, and refrigeration passes through the annular space in the outer pipe. Where possible, there should be counter flow of the refrigerant and the condensing water to maintain maximum temperature differences. 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 strike a balance so that the quantity of water insures economical compressor operation. As part of the condenser, or attached to it, there must be storage space for liquid refrigerant. The installation of all equipment should be made accessible for inspection, repair, and cleaning. Both the coolers and condensers should have space for pulling tubes. Because there is a decided tendency to conserve the water in city mains and most large cities are restricting the use of water, in order to use air conditioning systems and refrigeration equipment it is often necessary to install cooling towers. The cooling towers, unfortunately, produce the warmest condensing water at the time when the load on the system is greatest, so that the refrigeration equipment must be designed to meet > . j ; ; . 194 Chapter 10--Cooling Methods lv the maximum load at normal conditions, but also the maximum in0Hat abnormal condensing water temperatures. If properly designed, akes little difference in the efficiency of operation throughout the Except at those times when the condensing water temperature is this occurs only for 5 per cent of the entire cooling period it can be disregarded as a factor in establishing yearly operating costs. The cooling tower has a certain advantage over the use of water from the citv mains in that the temperature of the condensing water varies directly with the outdoor temperature and, as pointed out, the refrigera tion load also varies with this temperature. Certain economies are pos sible when a cooling tower is used which cannot be achieved by the use of condensing water from city mains, even where the city water temperature is extremely low. Normally, the lowest city water temperature met during the summer months is from 65 to 70 F. This temperature range takes olace for the entire cooling period, regardless of what the outdoor, tempera tures'are. With the cooling tower, the temperature of the condensing water may rise to 80 or 85 F under maximum conditions, but under less than maximum conditions the temperature of the water off the cooling tower drops considerably, and it has been established that 50 per cent of the time the outdoor wet-bulb temperature varies from 60 to 70 F and the cooling tower water, therefore, for the same periods, varies from 65 to 75 F. When the outdoor wet-bulb temperature drops below 60 F, which occurs approximately 30 per cent of the time, the condensing water temperature is still lower. The cost of, water used for condensing is negligible, as'the only water required is that used to, make up the loss by evaporation in the cooling tower itself. See also Chapter 11. PROBLEMS IN PRACTICE 1 Discuss the difference in results obtained in cooling and dehumid ifying in an air washer from those obtained in a surface cooling coil. Air leaves a dehumidifying air washer in a saturated condition at a dew point tempera ture which can be easily maintained at a constant level by controlling the spray water temperature. This saturated air may then be reheated to proper delivery temperature by reheating coils or by mixing with bypassed air. For a set air velocity and a set mean refrigerant temperature, a given cooling coil is capable of absorbing a definite amount of heat. Whether the air-leaving the coil is saturated or not depends then on the entering dry- and wet-bulb temperatures. From, practical operating standpoint, the easiest way to control the output of the cooling'coil is by means of the dry-bulb temperature of the conditioned space. This means then that the final dew point will vary somewhat depending on entering air conditions. Summarizing then, the air washers permit close control over both-final dry-bulb and final dew point temperatures, while the surface coolers permit close control over the final dry-bulb only. ....................... ' . 2 For condensing purposes, an air conditioning system uses city water which has an average 70 F supply temperature. The following table lists the number of hours per year during which definite wet-bulb temperatures and corre sponding refrigeration rates pertain. ' 195 of andAmerican Society Heating Ventilating Engineers Guide, 1936 ; Wet-Bulb Temperature F 80 . 79-75 74-70 69 - 65 fit - 60 59-55 54-50 No* ot . ; Hours '* ' per Year . 6 100 277 330 277 158 52 . . Refrigeration Required . Tons 284 233 183. 157 144 79 37 ' : Total 1200 hours If the power requirements of a dichlorodifluoromethane refrigeration system are in accordance with the following data on partial load operation, determine the seasonal power cost at 2 cents per kwhr: Tons of Refrigeration Kw per ton Seasonal power cost: 284 0.89 233 183 157 144 0.89 0.87 0.86 0.86 .. 79 37 0.93 0.97 : Wet-Bulb . Temperature F ' , Ton-Hours . - Kwhr 80 79 - 75 74 - 70 69 - 65 64-60 59 - 55 54-50 6 X 284 = 1,704 100 X 233 = 23,300 277 > 183 = 50,700 330 X 157 = 51,800 277 X 144 = 39,900 158 X 79 = 12,500 52 X 37 = 1,920 1,704 X 0.89 = 1,517 23,300 X 0.89 = 20,750 50,700 X 0.87 = 44,100 51,800 X 0.86 = 44,500 39,900 X 0.86 = 34,300 12,500 X 0.93 = 11,600 1,920 X 0.97 = 1,860 ' Totals 181,824 ton-hours 158,627 kwhr The 158,627 kwhr at 2 cents per kwhr will cost $3,173. ~ .. ,, , los.oz/ Kwnr -, . The average consumption will be 1, 81,-8.2d4.--t-o--n----h:-o--u--r--s = 0.873 kw per ton. . 3 Using the data of Question 2, if a cooling tower were installed for re-using the condensing water, estimate the annual operating cost of a dichlorodifluoro methane refrigeration system if the final temperatures of the water leaving the cooling tower and the kilowatt input per ton ai-e the following: Tons ' Temperature of water leaving tower, F Kw input per ton 284 233 86.7 81.8 1.10. 0.94 183 76.5 0.85 157 144 . 79 . 72.1 66.4 61.3 0.80 0;74 0.59 37 55.6 0.62 . Wet-Bulb Temperature F. *- Ton-Hours . . Kw pEn Ton .. . : Kwhr ` 80 . 79 - 75. 74-70 69 - 65 64-60 59 - 55 . . : 54 - 50 . - 1,704 23,300 50,700 51,800 39,900 12,500 1,920 .X X X X. .X X .X 1.10 0.94 0.85 0.80 0.74 0.59 0.62 1 : 1,875 . 21,900 43,300 41,400 ' 29,500 7,370 1,200 . Totals______________ 181,824 ton-hours 146,545 kwhr The 146,545 kwhr`at 2 cents per kwhr will cost.$2,931. The average consumption will be lgl^il^i^^ours =- P^^kw per ton,. _ , 196 : Chapter: 10--Cooling Methods i the data from Question 2, if city water costs 20 cents per thousand 4 if 1.25 gallons are used per minute per ton, estimate the annual water cost. ^ ^ 25 = 75 gal per ton-hour. , 181,824 ton-hours' X 75 = 13,620,000 gal per year. 13,620,00Q_X $0.20 _ g2,724, the yearly cooling water cost. 5 If a steam ejector system were used to secure the refrigeration for the air conditioning system of Question 2, compute the annual steam cost if steam is sold for 53 cents per thousand pounds and if there is an average steam con sumption of 20 lb of steam per hour per ton when used with a Cooling tower system* .- 181,824 tons X 20 lb of steam per ton = 3,636,480 lb of steam. . The 3,636,480 lb at 53 cents per thousand pounds will cost $1,929. 6 From the data given in the following table covering auxiliary equipment, make a comparison between the operating costs of the complete dichlorodifluOromethane system of Question 4 and the complete steam ejector cooling system of Question 5. A cooling tower is used for condenser water recovery. Plant Operation Dichlorodifluoromethane System . Steam Ejector 1 System ,, ____ Discharge head on chilled water ft--..-- ------ Chilled water temperature, F........ . 1200 17.8 30.2 1200 75 75 80 46 1200 35.6 47.8 1200 75 75 80 46 .; The flash tank or evaporator of the steam ejector system is of the open type, the flash water being pumped directly to the sprays of the washer used for cooling the air. Dichlorodifluoromethane System: Power requirements, Cooling tower fan Cooling tower pump 17.8 bhp 30.2 Total 48.0 bhp 48.0 bhp X 0.746 X 1200 hr Power for cooling tower system = ------ 0.80 motor efficiency " 53,700 kwhr. The water cooler in a dichlorodifluoromethane system of the surface type requires no additional pumping head other than the friction drop through the cooler, which in this problem is estimated to be 10 ft. The total pumping head is, therefore, 75 + 10 = 85 ft. Power required for the chilled water system will be, . 1200 gpm X 8.34 lb per gallon X 85 ft head 33,000 ft lb X 0.75 pump efficiency 34.3 bhp. 34.3 bhpX 0.746 X .1200 hr = 0.80 motor efficiency Thus, the total power required by the auxiliary equipment will be' 53,700 + 38,300 = 92,000 kwhr.. The 92,000 kwhr at 2 cents per kwhr will cost The power cost of refrigeration, from Question 4, is $i;840 2,931 The total annual power cost, using a dichlorodifluoromethane system, is $4,771 : American Society of Heating and Ventilating Engineers Guide, 1936~~ Steam Ejector System: Power requirements, Cooling tower fan Cooling tower pump 35.6 bhp 47.8 Total 83.4 bhp dPower f,or cooling tower systtems = 8--3--.-4- -b--h--p----X---0--.-7--4--6---X----1--2--0-0---h--r- = ,,903,300 ,kwh, r.. 0.80 motor efficiency In the flash tank or water cooler of the steam ejector system, the water is at a pressure corresponding to the chilled water temperature required. In this case it is at 46 F, which corresponds to an absolute pressure of 0.1532 lb per sq in. or 0.3118 in. Hg. This increases the pumping head on the chilled water circulating pump by 14.7 -- 0.15 = 14.55 lb per square inch, or 33.5 ft. The total pumping head is, therefore, 75.0 + 33.5 = 108.5 ft 1200 gpm X 8.34 lb per gallon X 108.5 ft head ' 33,000 ft-lb X 0.75 pump efficiency ' P' 43.7 bhp X 0.746 X 1200 hr ,,,,,, , , _ ------0--.-8--0---m---o--t-o--r--e--f-f-i-c-i-e--n--c--y------- = 48,800 kwhr. The total power required by the auxiliary equipment is 93,300 + 48,800 = 142,100 kwhr. The 142,100 kwhr at 2 cents per kwhr will cost The cost of the steam, from Question 5, is $2,842 1,929 The total annual power cost, using a steam ejector system, is $4,771 These calculations indicate that for the assumptions made, both the dichlorodifluoro- methane system and the steam ejector system would cost 2.6 cents per ton-hour to operate. In order to obtain a complete analysis it would be necessary to compare the fixed charges which include interest, depreciation, obsolescence, and maintenance. These are customarily computed at 15 per cent of the initial cost per annum. To this cost must be added the cost of refrigerant make-up per year. In the steam system this is negligible, but in the dichlorodifluoromethane system it may be approximated at from % to of the refrigerant charge per year. 7 If, in a given air conditioning installation, fixed charges are estimated at 15 per cent per annum, what increased first cost would be justified for an auxi liary appliance on a refrigeration machine which could save $125.00 per year in operating cost? si nn $125.00 capitalized at 15 per cent is, --^ - ^ = $834.00 increased first cost justified. 8 Electrically driven Freon condensing units are to be used in an air con ditioning system, requiring 20 tons refrigerating capacity for conditions of maximum load. An overall analysis of the seasons operating conditions shows an average load factor of 62.5 per ceiit, and allowing for variable time intervals of operation of refrigeration units installed, three-quarters of the operating season, or 750 hours, would require operation of the equipment at one-half load, and one-quarter of the operating season or 250 hours full load capacity of the' refrigeration equipment would be required. ' . The increased first cost of 2--10 hp, 10 ton condensing units over 1--20 hp, 20 ton condensing unit is, $830.00 installed price, to the customer. The increased first cost of a 2-speed compressor motor.of 20 hp size over a con stant speed 20 hp size motor including increased starter cost is $210.00. The efficiency of the 2-speed motor above is 83 per cent at full load full speed, and 79 per cent for full load at ^ speed. At )^-speed, full load is U total bhp of full load full speed. , Discuss the considerations involved in making a decision as to whether a single unit with a 20 hp motor of the 2-speed type would be used in preference to 2-10 hp constant speed units. . 198 Chapter 10--Cooling Methods f 2-10 ho 10 ton units in excess of 1-20 hp, 20 ton unit with 2-speed motor, is The cost oi*- IQ20.00, increased first cost. At 15 per cent fixed charges, this J830.00--annual cost of $93.00 for 2 compressors over one compressor, represents an ^ compressors instead of one compressor on an installation of this type, The advantag ^ service provided in the event one compressor is shut down for repairs is in the brea operated at one-half capacity utilizing the duplicate machine. The the.system t^e constant speed unit would be higher at full load than would be motor emc the 2-speed motor at low speed. Offsetting this latter advantage the efncien y t|,at the condenser on the condensing unit would provide a lower however, i dens;ng temperature for M load operation with the same final condensing refngeranr^^^ would be the case with duplicate units each furnished with its water temper^ condenser. Operation at a lower condensing temperature would own comp ^ wer saVing compensating for the lower efficiency of the 2-speed motor Ps>Vld nerated at slow speeds. It is, in a case of this kind, purely a question as to whether when oper _urcjiaser would deem an investment of $620.00 more and an increased fixed or not t a yearj advisable to get breakdown service thru the-installation of a Prate units. In most cases, this increased first cost would not be warranted because fth fact that satisfactory indoor conditions could not be obtained at full load if only one-half the refrigeration capacity were available. 9 For an increased first cost of $210.00 for a 20 hp, 2-speed motor over a 20 hp ' ccmstant speed motor to be used on a Freon automatic condensing unit for air conditioning duty, justify the increased investment based on a load factor of 62 5 per cent, on an operating basis of 1000 hours total of which % of the opera tion of the refrigeration equipment would be at j-fj load and 14 of the operation season at full load. Motor efficiency 2-speed, 83 per cent, at full speed; and! 79 per cent at half speed. Motor efficiency constant speed motor 83 per cent. City water is to be used for condensing purposes and is to be automatically controlled from the discharge pressure by means of automatic regulating valve. Compute increased first cost justifiable based on 15 per cent fixed charges and number of years required to pay off increased first cost. At full load for 20 bhp load and 83 per cent efficiency, the kw input to the compressor motor would be 20 bhp times 0.746 kw per bhp divided by 83 per cent motor efficiency or 18.0 kw. At ft speed, --10 bhp X 0.746--k--w---p--e--r--h-p-- = 9_.45 kw input at H. speed, . 0.79 efficiency - For a constant speed motor installation, 1000 hours operation at 18 kw load, requires 18,000 kwhr per season for operation. With 2-speed motor 750 hours at Yl speed and 9.45 kw input = 7080 kwhr. For full speed operation, 250 hours at 18 kw input = 4500 kwhr. The total kwhr required with 2-speed motor = 7080 + 4500 = 11,580 kwhr. From the above it is seen that the power consumption is reduced by the use of a 2-speed motor from 18,000 kwhr per year to 11,580 kwhr or approximately a power saving of 35 per cent annually. For power at $.02 per kwhr, 6400 kwhr saving per year would mean a saving of $128.00 per year, which at 15 per cent would justify an increased first cost of $853.00. Further, the fixed charge added due to the increased first cost of a 2-speed motor would be 15 per cent of $210.00, or $31.50 per year, thus the net annual saving after correcting (or fixed charged due to increased investment would be $128.00 less $31.50 fixed charge or a net annual saying of $96.50 with a 2-speed motor based on a power cost of $.02 per kwhr. Thus the increased first cost of $210.00 would be returned to the purchaser in $210.00 -4- $96.50 or 2.18 years. Similarly a $.03 power the gross saving exclusive of additional fixed charges to increased cost of 2-speed motor would be $192.00; net saving per year $160.50 and therefore, the 2-speed motor would pay for itself in 1.31 years. For $.04 power, the gross saving would be $256.00;'net saving, $224.50 and the 2-speed --mtor would be paid for in 0.935 years. 199 of and 1936American Society Heating Ventilating Engineers Guide, It is safe to assume that any appurtenance which will pay for itself in less than 5 yjj. when computed on the above basis, will be accepted by practically all purchasers of a;S conditioning equipment, provided an analysis of the above type is properly presentee/ 10 In a locality where the electric power rate is based on a demand charge, it i is desired to install the smallest possible compressor motor which will provide summer cooling for, a 300-seat restaurant which operates 6 hours per day from 11 a.m. to 2 p.m., and from 5 p.m. to 8 p.m. The refrigeration load at the peak is 28 tons. If the load factor for both the noon and evening meals is 70 per cent, discuss the type of equipment which would take the greatest advantage of the reduced power rate at low kilowatt demand. Chapter 11 humidification and HEHUMIDIFICATION A storage system using a chilled water storage tank would permit the installation of a refrigeration system having the smallest motor. . For a 28-ton system operating 6 hours per day at a 70 per cent load factor, on the maxi mum day the total heat removed would be, . 28 tons X 6 hr X 0.7 = 117.5 ton-hours per day. A'r Washers, Atmospheric Water Cooling Equipment, Cooling Towers Design Wet-Bulb Temperature, Cooling Ponds, Natural Daft Deck Type Towers, Mechanical Draft Towers, Winter Freezing, vr J Apparatus for Industrial Conditioning . . . If a compressor were to operate 24 hours at a constant rate, its average capacity would be -- 24^hours UrS = tons, or approximately 5 tons. If operated 12 hours per day, the compressor capacity would have to be increased to 10 tons. A water storage tank would store the refrigeration and allow off-peak operation, so a smaller compressor motor could be used. However, the suction temperature at which the compressor would be operated would be lowered approximately 5 to 10 F. This would increase the horsepower per ton of refrigeration, when dichlorodiflourOmethane is used, approximately 10 per cent for a 5 F reduction and 24 per cent for a 10 F reduction in the suction temperature. Rather than store the water at too cold a temperature, it would be more economical to install a larger, storage tank and use a higher temperature. A 5-ton compressor running during periods when there are no customers, namely, during the 15 hours from 8 p.m. to 11 a.m. will have stored 15 hr X 5 tons, or 75 ton-hours, of refrigeration in the storage tank by 11 a.m. As one ton-hour equals 12,000 Btu, 75 X 12,000 Btu, or 900,000 Btu, will have been stored. . If the apparatus dew-point temperature is 54 F, and the chilled water is supplied to the air washer at 48 F, it will leave at 54 F. If the water in the storage tank is at 40 F, the' temperature difference between the stored water and the water entering the washer will be 48 F -- 40 F = 8 F. This is equivalent to an available 8 Btu of cooling effect per lb of water stored. Therefore, 8 or 112,500 lb of water must be stored. This is 112,500 = 13,500 gal water to be stored, which equals 13,500 8.34 7.5 = 1800 cu ft of water. : $. The storage tank to hold this water might be 6 ft high, 7J4 ft wide, and 40 ft long. Should this volume prove impractical, a proportionately smaller tank could be used if the water storage temperature were reduced. Should a 10-ton refrigeration system be used, the water, quantities and tank capacity could be reduced by one half, and the refrigeration plant need not be started until 8 a.m. d'dily, which might prove of additional advantage. If refrigeration is stored by freezing ice on coils, considerable storage space will be saved but more power input per Btu of cooling will be required. . . I I f I EOUIPMENT for humidifying and dehumidifying is of varied character and its functions will be discussed in this chapter. An air washer is essentially a chamber in which air is brought into intimate contact with water the object being (a) to wash the air or (b) to regulate the moisture1 content of the air and at the same time wash it. The air comes in contact with the water by passing it through water sprays or by passing it over surfaces wetted by a continuous flow of water; hence the classification:; spray, scrubber, and combination spray and scrubber type washers. A washer chamber may be constructed of wood, or.stone, but it is most often constructed of sheet metal. The lower portion of it is specially designed as a tank to receive the water dropping through the chamber and to serve as a reservoir from which the water may be recirculated. It is desirable that air leaving a washer, contain no water in suspension. For this reason eliminators are provided at the washer outlet. These may be in the. form of plates or baffles upon whidi the free moisture is deposited as the air is deflected through several changes from its original direction of flow. In some washer units steel wool filter sections serve as eliminators. However, specially designed plates are used more gener ally than other devices because they offer the least resistance to the flow of air, while still performing effectively the function of free moisture elimination. They also have the advantage of acting as scrubber surfaces when flooded. .. . It is essential to. uniform performance in a washer, that air enter evenly distributed over the washer inlet. To insure this, a perforated plate or eliminator plates are installed at the inlet.. Eliminator plates ate now, more generally used. They serve a second purpose in preventing the' escape of spray through the washer inlet. .. . Water is supplied to scrubber type units through flooding nozzles.. Thecapacity of these nozzles varies with the manufacturer although a fair value of 5 gpm may be used. The nozzles are spaced on,one-foot centers across the top of the washer over the scrubber plates- ' ; , Water is supplied to spray type units through atoiiiizing nozzles gener ally arranged in banks across the washer. The nozzles spray either in the direction of the air flow, that is, downstream, or agairiSt the air flow, or upstream. Nozzle capacities vary with the manufacturer, from. \-x/i to . 2 gpm at a water pressure of about 25 lb per square inch which pressure . 200 of andAmerican Society Heating Ventilating Engineers Guide, 1936. Chapter 11--Humidification and Dehumidification is required for effective atomization. The spacing of spray nozzles is determined by the water requirements of the particular installation. j{ spray type washer may contain one, two or three banks of nozzles depend ing upon its application. When an air washer is used for cleaning air it removes impurities and dusts. In general it does not function as efficiently in this service as a filter. For non-microscopic soluble dust its efficiency, averages about 50 per cent, unless the concentration of dust is high. Its effectiveness in removing greasy microscopic dust is practically negligible as is also its deodorizing ability. When a washer is used to regulate the moisture content of air it adds moisture to (humidifies) or removes moisture from (dehumidifies) the air to achieve the desired moisture content. When air passes through a washer wherein water is circulated without the addition or removal of heat, the air tends to become saturated at its entering wet-bulb temperature. What occurs here is partial or complete adiabatic saturation. The total heat content of the air is unchanged, inasmuch as the dry-bulb temperature of the air drops in proportion to the amount of additional water evaporated. This action is also known as evaporative cooling. A measure of the washer's effectiveness under these conditions is its saturating efficiency which is equal to the drop in drybulb temperature in per cent of the entering wet-bulb depression. Other things being equal, the saturating efficiency of a spray type washer is a function of the number of spray banks and the direction in which they spray. The following table gives a general comparison: H midifiers may be figured on the same basis as dehumidifiers; the . water temperature, of course, will be higher than the wet-bulb temperature of the leaving air. The problem of cooling or heating the circulated water before returning . tjjg washer chamber is external to the unit. It will suffice here to ote that heating is generally accomplished by passing the water through dosed hot water heaters or by injecting steam into the water circuit; cooling, by passing the water through closed coolers or over refrigerating coils in a Baudelot chamber. Often in a cooling and dehumidifiying application, the refrigerating coils are located within the washer chamber. 3 banks--2 upstream--X downstream.--............ 100% saturation efficiency 2 banks--2 upstream_____________________ 95% saturation efficiency. 2 banks--1 upstream--1 downstream.-.............. 85% saturation efficiency 1 bank --upstream............... 80% saturation efficiency X bank --downstream.............................................. 65% saturation efficiency When air passes through a washer wherein the circulated water is either cooled or heated before being returned to the spray chamber, a heat interchange between the air and water occurs, and the air tends to become saturated at the temperature of the leaving water. The extent to which the leaving air and leaving water temperatures approach each other is an index to the effectiveness of the washer under the operating conditions. The total heat absorbed by the water in the process equals the total heat given up by the air, or the heat given up by the water equals the heat absorbed by the air. Depending on whether the moisture con tent of the air is increased or decreased during the operation, humidifi cation or dehumidification occurs. Heat will be added to or removed from the air as the water supplied is of a higher or a lower temperature Washers are sometimes arranged in two or more stages to cool through long ranges or to increase the over-all efficiency of heat transfer between air and the cooling or heating medium (water, brine, etc.). ,A multi-stage washer is equivalent to a number of washers in series arrangement. Each stage is in effect a separate washer. than the wet-bulb temperature of the entering air. ' . Usually the catalog capacity of a washer is expressed in cubic feet of For dehumidifiers, the ratio of the difference between the leaving wet- air per minute and is based upon an air velodty of 500 feet per minute ' bulb and the leaving water to .the difference between the entering wet- through the gross cross-sectional area of the unit above the water level in bulb and the entering water may be figured as follows: its tank. At this rating spray type washers handle about 2-j/j gpm of 3 banks--1 downstream--2 upstream. ........... ........................... ................. 0% 2 banks--2 upstream. ...... ...... ...... ............... . ................. 5% 15% water per bank per square foot of area, that is, about 5 gpm per bank per 1000 cfm. These proportions of air, water, area, and velodty may be departed from to meet the needs of some particular job, but certain 20% limiting relationships should be observed. Two of the more important 1 bank --downstream................................ ............. ........ .........35% items are: 202 203 of andAmerican Society Heating Ventilating Engineers Guide, 1936 . a. Choose a washer for-air velocities. above approximately 300 fpm and below approximately 600 fpm. Velocities outside this range, are likely to result in fauW elimination of entrained moisture. - .TM b. When a high saturating efficiency is required, select a two or three bank sprav type unit, having a total water capacity of not less than 15 gpm per 1Q00 cfm. " The area of a washer may be dictated by space limitations outside the washer, such as headroom, or by space requirements inside washer, such as face area needed by a bank of cooling coils; The length of a washer is determined by the number of spray banks, or scrubber plates, and if cooling coils are installed in the unity by the number of banks of coils Roughly, a spray space of about 2 ft 6 in. in length is required for each bank of sprays, (the leaving eliminators require about 1 ft 6 in., entering eliminators about 1 ft). * The resistance to air flow through an air washer varies with the type eliminators, number of banks of sprays, direction of spray, type of scrub- Fig. 3. Air Washer with Spray Water Heating Arrangement ber plates, and, if cooling coils are located in unit, by their size and type. Washers should be selected to limit static resistances below 0.50 in. Power Requirements - ' " The approximate power requirement for passing 10,000 cfm of air through a humidifier of the spray type by a fan of 78 per cent mechanical efficiency is given in Table 1, this being the fan brake horsepower for various velocities and static pressure losses. Allowance should be made for variations in static pressure due to the use of different diffuser plates or inlet louvers and for variaticHmin fan efficiencies. : ATMOSPHERIC WATER COOLING EQUIPMENT To successfully operate a refrigerating plant or a condensing turbine, the heat from; the compressed refrigerant or the discharged steam must be removed and dissipated. This is accomplished ordinarily by first trans ferring; the heat of the gas to water in a heat exchanger. If the plant is situated qn the. banks of a; river or lake, an intake maybe had. upstream or. at a considerable distance, from the discharge, to prevent mixing of the heated discharged water with the inlet water. If the source of water is a city supply or well water, the discharge water may be run into the nearest sewer or open waterway. . Lacking, an unlimited water supply, or in cases where city water is too expensive or where the water available contains 204 Chapter 11--Humidification and Dehumidieication ________~ . i salts which would quickly form scales on the heat-exchanging, dissolved necessary to recirculate the water, and to cool it after each apparatus^^k the heat-exchanger by exposure to air in an atmos- PhfHc water cooling apparatus. a- has a capacity for absorbing heat from water when the wet-bulb ture of the air is lower than the temperature of the water with tempera which * contact. The rapidity with which this transfer of heat occurs the aj.ea of water in contact with the air, (2) the relative dePe" of the air and water, and (3) the difference between the wet-bulb VC nerature of the air and the temperature of the water. Because the t?mlP~ rate do not occur in direct proportion to changes in the govern - factors, data on the performance of atmospheric water cooling equip- mint are largely empirical. - . .......... Table 1. Approximate Fan Brake Horsepower _ . ntg for passing 10.000 cfm of air through humidifiers at various velocities and static pressures. Mechanical efficiency of fan 78 per cent.;________________________________ __________________________ Velocity mi ........ 30 Deg Eliminators Spaced 1-Hon in- Centers Static Pressure In. Water BHP "" 45 DegElminators Spaced on 2-H In. Centers " Static Pressure In. Water ` BHP 500 0.20 0.40 0.40 . 0.80 . 550 0.24 0.48 0.48 0.97 600 0.29 . 0.58 0.58 1.15 650 0.34 0.68 0.68 1.35 As the heat content of the air increases, its wet-bulb temperature rises. (See Chapter 1.) Because it is impractical to leave the air in contact with water for a long enough time to permit the wet-bulb temperature .of; the air and the temperature of the water to reach equilibrium, atmos pheric water cooling equipment aims to circulate only enough air to cool the water to the desired temperature with the least possible expenditure of power. . Cooling Towers .` . . . In an air washer, humidifier or dehumidifier, the air is first conditioned by water to change its moisture and temperature, and it is then sent to the place where it is to be used. In water cooling equipment the tem perature of the water is reduced by. air, and the cooled water is carried, to its point of usage. In the air washer, an excess of water is used to con dition a fixed quantity of air, while in Water cooling equipment, an excess quantity of air is used to cool a fixed quantity of water. , . ., Both types of equipment have a common basis of design, however, in that the size of the equipment is determined by the quantity of air that "must be handled. With the air washer, the size of the equipment is fixed by the quantity of air to be conditioned, and the amount of conditioning is controlled by the quantity and temperature of-the water supplied and its method of application. With water cooling apparatus, its'size and.the quantity of air required.bear no direct relation to the quantity of water being cooled, but vary through a wide range-for different services and conditions. .....bibb'"b.-Oi' 205. of andAmerican Society Heating Ventilating Engineers'Guide, u Sizes of Equipment Assuming a definite quantity of water to be cooled, the size and design of atmospheric cooling equipment are affected by the following factors: 1. Temperature range through which the water must be cooled. 2. Number of degrees above the wet-bulb temperature of the entering air to which the water temperature must be reduced. 3. Temperature of the atmospheric wet-bulb at which the required cooling must be performed. 4. Time of contact of the air with the water. (This involves height or length of the apparatus and velocity of air.) . 5. Surface of water exposed to each unit quantity of air. - 6. Relative velocity of air and water. Table 2. Condenser Design Data A- ^' i ` b |- r G^s Maximum Pressure Desired in Condenses Gas Temperature in Condenses F Steam.... ............. Ammonia 185 lb gage head pressure.....: Carbon dioxide.. 1030 lb gage head pressure___ Methyl 102 lb gage chloride...... .. head pressure...... Dichlorodi- . 117 lb gage fluoromethane head pressure...... 99.7 li.4.3 126.0 96.0 86.0 100.0 100.0 Leaping Hot Water Tempbraturi F Best Design Average Design 97 93 110 105 120 114 92 88 88 81 96 92 96 93 r1 ' Items 1, 2, and 3 are established by the type of service and geographical location, while items 4, 5, and 6 depend upon the design of the equipment. The establishment of a proper cooling range depends upon: 1. Type of service (refrigerating, internal combustion engine and steam condensing). 2. Wet-bulb temperature at which the equipment must operate satisfactorily. 3. Type of condenser or heat-exchanger used. XI Because the design of an entire plant is usually affected by the quantity and temperature of the cooling water supply, plants should be designed for cooling water conditions which can be most efficiently attained. The first consideration is usually the limiting temperature of the plant. For example, if an ammonia compressor refrigerating plant is to be designed for 185 lb head pressure as a normal maximum, the limiting temperature of the ammonia in the condenser is 96 F. Should the ammonia temperature go above this figure the head pressure will exceed 185 lb and power con sumption increases. To obtain this head pressure, the temperature of the circulating water leaving the condenser must always be less than 96 F by an amount depending upon the size and design of the condenser, the quantity of water being circulated, and the refrigerating tonnage being produced. A condenser having a large surface per ton of refrigeration may be designed to operate satisfactorily with the leaving hot water temperature within 3 deg or 4 deg of the ammonia temperature cor responding to the head pressure, while a small condenser might require a 10 deg difference. 206 S' si; S i. II ? %; lt 1I i; * 11--Chapter Humidification and Dehumidification T ble 2 lists several gases with data as to the temperatures and pres1 a f which commercial condensers are designed. Internal combustion SU^nes have limiting hot water temperatures of 125 F to 140 F. The 60 ine of such fluids as milk or wort has variable requirements and is Callv done in counter-flow heat-exchangers in which the leaving circu lating water is at a much higher temperature than is the leaving fluid. The temperature range, once the hot water temperature is approxi mately known, depends upon: 1 Maximum wet-bulb temperature at which the full quantity of heat must be Design Wet-Bulb Temperatures ' The maximum wet-bulb temperature at which the full quantity of water must be cooled through the entire range is never, in commercial design, the maximum wet-bulb temperature ever known to exist at the location nor the average wet-bulb temperature over any period. The former basis would require atmospheric cooling equipment several times greater than normal size, and the latter would result during a large part of the time, in higher condenser water temperatures than those for which the plant was designed. For instance, the maximum wet-bulb temperature recorded in New York City is 88 F, and the July noon average for 64 years is Close to 68 F. Yet in the years 1925 to 1931, inclusive, there were but 6 hrs per year when the wet-bulb temperature reached 80 F or more, and there were 975 hours in the average summer (June to September, inclusive) when' the wet-bulb temperature was 68 F or above. As these 975 hours represent a third of the summer period, cooling equipment based upon the noon average July wet-bulb of 68 F would be inadequate. Commercial practice is to choose a wet-bulb temperature for refrigeration design purposes which is not exceeded during more than 5 to 8 per cent of the summer hours (75 F for New York City), with somewhat lower requirements for steam turbines and internal combustion engines. This difference is made because the heaviest load on a refrigerating plant is coincident with high wet-bulb temperatures, whereas the heaviest electric power demand occurs either in the winter or after nightfall in summer, when the wet-bulb temperature is low. Table 1, Chapter 8, shows safe design wet-bulb temperatures which will not be exceeded more than 8 per cent of the time in an average summer. 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 efficiency range of the type of atmospheric water cooling apparatus to be used. Efficiency of atmos pheric water cooling apparatus is expressed as the percentage ratio of the actual cooling range to the possible cooling range. Since the wet-bulb temperature of the entering air is the lowest temperature to which the water could possibly be cooled this is: . Percentage cooling efficiency of atmospheric water cooling equipment = (hot water temperature -- cold water temperature ) X 100 hot water temperature -- wet-bulb temperature of entering air 207 of andAmerican Society Heating Ventilating Engineers Guide, 1935 Efficiencies of various types of atmospheric water cooling apparatus vary through wide limits, depending upon air velocity, concentration of water per square foot of area, and the type of equipment. The commercial range of efficiencies is given in Table 3 although unusual designs may operate outside these ranges. . From consideration of the factors which include the cooling range and design wet-bulb. temperature, the quantity of water required can be calculated from the amount of heat to be dissipated. The normal amounts of heat to be removed from various parts of the cooling equipment are: Compressor refrigeration............................... 220 to 270 Btu per minute per ton Condenser turbine....... :.................................. 950 to .980 Btu per pound of steam Steam jet refrigerating apparatus...............1030 to 1150 Btu per pound of steam Diesel engine..... .......-.................................... 2800 to 4500 Btu per horsepower Cooling Ponds . A natural pond is often used as a source of condensing water. The hot water should be discharged close to the surface at the shore line, as natural air movement over the surface of the water will cause evaporation Table 3. Efficiency of Atmospheric Water Cooling Equipment ' Equipment Spray. Ponds............................................ Spray Towers............._.................. ......... Natural Draft Deck or Atmospheric Towers.....1............................................ Mechanical Draft................................... Cooling Efficiency--Peb Cent Minimum Usual ' Maximum 30 45 to 55 40 45 to 55 60 60 35 SO to 70 . 90 35 55 to 75 90 and carry away heat. Because increased density due to the loss of heat causes the cooled water to sink to the bottom of the pond, the suction connection for intake water should be placed as far below, the surface as possible, and at as great a distance from the discharge as practicable. Spray Cooling Ponds .." . ' . The spray pond consists of a basin, above which nozzles are located to spray water up into the air. Properly designed spray nozzles break .up the water into small drops, but not into a mist because, the individual drops must be heavy enough to fall back into the basin and not drift off.: The water surface exposed to the air. for cooling is the combined area of all the small drops. Since the rate of heat removal by atmospheric water cooling is a function of the area of water exposed to the air,'the difference in temperature between the water and the wet-bulb temperature of .the air, the relative velocity of air and water, and the duration of-contact of the air with the water, a much larger quantity of heat may;be,'dissipated in a given area with the spray pond than with the cooling pond, because of (1) the speed with which the drops travel as they are propelled into the air and fall back into the water basin, (2) the increased wind velocity at a point above the surrounding structures or terrain, (3) the increased 208 Chapter 11- -Humidification and Dehumidification olume of air used, and (4) the vastly increased area of contact between ajr and water. Soray pond efficiencies are increased by (1) elevating the nozzles to a ,. Jer p0int above the surface of the water in the basin, (2) increasing the acing between nozzles of any one capacity, (3) using smaller capacity SP zzles to decrease the concentration of water per unit area, and (4) n0- Smaller nozzles and increasing the pressure to maintain the same USncentration of water per unit area. Usual practice is to locate the nozzles from 3 ft to 6 ft above the edge of the basin, to supply from 5 lb to 12 lb pressure at the nozzles, using nozzles spraying from 20 gpm to 60 gpm each and spacing them So the average water delivered to the surface of the pond is from 0.1 gpm per square foot in a small pond to 0.8 gpm per square foot in a large pond. . Increasing the pressure, spacing the nozzles farther apart, or increasing the elevation of the nozzles will increase the cross-section of spray cloud exposed to the air, and therefore increase the quantity of air coming in contact with the water. Best results are obtained by placing the nozzles in a long relatively narrow area located broadside to the wind. Spray ponds may be located on the ground if they have an earthen or a concrete basin, or they may be placed on roofs having special waterproof roofing. To prevent excessive drift loss, or the carrying of entrained water beyond the edge of the pond by the air on the leeward side, louver fences are required for roof locations and for those ground locations where space is so restricted that the outer nozzles cannot be located at least 20 ft to 25 ft from the edge of the basin. Such fences usually are con structed of horizontal louvers overlapping so the air is forced to turn a corner in passing through the fence, and the heavier drops of water are thrown back, owing to their inertia. The louvers also restrict the flow of air, particularly at the higher wind velocities, and thus further reduce the possibility of water being carried off.. The -height of an effective fence should be equal to the height of the spray cloud. Louver boards are preferably of red gulf cypress or California redwood supported on castiron, steel or wood posts. Where building ordinances forbid the use of combustible materials, sheet metal is customarily used. . Algae formations may be a considerable nuisance in a spray pond. Such growths are killed by the periodic addition of potassium permanga nate to the pond water. Addition of the dissolved chemical should be made until the water holds a faint pink color for at least 15 min. Spray Cooling Towers Where not more than 30,000 Btu per minute are to be dissipated, the spray cooling tower is a satisfactory apparatus. The word tower in this connection is somewhat of a misnomer as the apparatus is essentially a narrow spray pond with a high louver fence. As usually built, the nozzles spray down from the top of the structure and the distance from the center of the nozzle system to the fence on either side is not more than half the distance that the nozzles are elevated above the water basin. Heights range from 6 ft to 15 ft and the total width of a structure is not usually greater than its height. Spray cooling towers occupy less space on small jobs than spray ponds of equivalent capacities because the towers have a capacity of from 0.6 gpm to 1.5 gpm per square foot of tower area. ' The 209 of andAmerican Society Heating Ventilating Engineers Guide, 1936 louvers are continually wet, and so add to the surface of water exposed to the cooling air. Natural Draft Deck Type Towers In past years most of the atmospheric water cooling on refrigeration work has been done with natural draft deck type towers, which are also referred to as wind or atmospheric towers. These towers consist of heavy wooden or steel framework from 15 ft to 80 ft high and from 6 ft to 30 ft wide, having open horizontal lattice-work platforms or decks at regular intervals from top to bottom, and a catch basin at the foot. The hot water is distributed over the upper part of the structure by means of troughs, splash heads, or nozzles, and it drips from deck to deck down to the basin. The object of the decks is to arrest the fall of the water so as to present efficient cooling surfaces to the air, which passes through the tower parallel to the decks. The decks also add to the area of water surface exposed to the air, but since they furnish a resistance to air flow, too many decks are a detriment. j To prevent the loss of water on the leeward side of the tower, wide splash boards are attached at regular intervals from top to bottom. These boards or louvers extend outward and upward, and in most designs the . top edge of each louver extends above the bottom edge of the one above it. - Efficiency of a deck tower is improved, within limits, by increased height, increased length, or increased width. The first two increase the area of water exposed to the wind, and the latter increases the time of contact of the air with the water. Wind Velocities on Natural Draft Equipment Since natural air movement is the prime requirement for a deck type tower, spray cooling tower, or spray pond, the apparatus must be de signed to produce the desired cooling on days when the wind velocity is below average when the wet-bulb temperature is at the maximum chosen for design, and when the plant is operating at full load. The. apparatus must also, for best results, be located with its longest axis at right angles to the direction of the prevailing hot weather breeze. Table 1 Chapter 8, gives the average summer wind velocities and directions in representative cities. Natural draft cooling equipment should be designed to operate properly with not more than one-half of the average wind velocity, and in no case should it need a wind velocity of more than 5 mph. If is obvious that natural draft towers and other natural draft equipment must be so located that they are not obstructed by trees, buildings, or other wind deflectors. Mechanical Draft Towers - Mechanical draft towers usually consist of vertical shells, constructed of wood, metal, or masonry, in which water is distributed uniformly at the top and falls to a collecting basin at the bottom.- The inside of the tower may be filled with wood checker-work over which the water drips, or the water surface may be presented to the air by filling the entire inside of the structure with spray fronfi nozzles. Air is circulated through the tower from bottom to top by forced or induced draft fans. Since the air flows counter to the water, the air is in contact with the hottest of the water 210 Chapter 11--Humidification and Dehumidification . . before leaving the top of the tower, and each unit of air picks up more hKit than a similar unit would on natural draft equipment, so the me chanical draft tower cools water by using less air than the other types of equipment need. As movement of the air through the towers is obtained bv power-consuming fans, it is essential that the air used be reduced to a minimum so as to secure the lowest possible operating cost. The efficiency of a mechanical draft tower is increased by increasing 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 it increases the pumping power needed. In creasing the area while maintaining constant fan power increases the air quantity somewhat and because of louvered velocities it increases the time 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 decreases the time the air is in contact with the water, but, since a greater quantity is passing through, the average differential between the water temperature and the 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 increases approximately as the cube of the air quantity. Air velocities through mechanical draft towers vary from 250 fpm to 600 fpm over the gross area of the structure. Mechanical draft water cooling equipment may be set up inside build ings, where it usually draws its air supply from the general space in which it is installed, and discharges its exhaust air through a duct to the outside. Indoor cooling towers may be either of the wood-filled or the spray-filled type. In many cases where little height but considerable area is available, water is cooled in a spray-filled structure similar to an air washer, with the air passing horizontally through the apparatus and being discharged through a duct to the outside. Such apparatus does not have the counter flow advantage of the vertical mechanical draft water cooling equipment, and therefore requires a much larger excess of air for proper operation. Air velocities and operating powers are considerably above those required by vertical mechanical draft water cooling equipment. Make-Up Water . Since the atmospheric water cooling equipment performs its functions chiefly by evaporating a portion of the water in order to cool the re mainder, there is a continual drain on the quantity of water in the system, and this loss must be replaced. Approximately 1 gal of water is lost for every 1000 gal of water cooled-per degree of cooling range; so if 1000 gpm of water are cooled through a 10 deg range, 10 gpm of water will be re quired to replace evaporated water. Replacement supply is usually regulated by a float control valve. Because the evaporation of the water leaves behind the salts which the water contained, high concentration of salts may make chemical treatment of the maker-up water necessary to avoid excessive deposits in the condensers. Winter Freezing < If atmospheric water cooling equipment is operated in freezing weather, the water may be cooled below freezing temperature so ice forms and of and 1936American Society Heating Ventilating Engineers Guide, collects until its weight, causes damage. To obviate freezing during con tinued operation, the efficiency of the apparatus may be lowered. This is done on the spray pond and the spray cooling tower by reducing the quantity of water fed to the apparatus, thereby lowering the pressure at the nozzles and increasing the size of the drops produced. On the deck Table 4. Comparison of Various Types of Atmospheric Water Cooling Equipment ` Figures indicate order of desirability Cooling Sprat Pond Pond Cost- ....................... :...............;........... -.......... X 5 Height......................................................... 1 Weight per sq ftJ.................;.......... ,, X Independence of wind velocity.................... 6 Drift nuisance................................ :..... 1 Make-up water required.............................. I Pumping head.................................................. 1 2 Suitability for congested districts............... X Water quantity required for definite , result...................... .................... :................ . , 6 2 4 2 X 3 6 6 2 1 5 5 Sprat Deck Mechanical Indooh Towbh Tower Draft Towsa 13 4 5 32 1 3 4-5 4-5 13 4 2 45 1-2 1-2 -5 4 2-3 2-3 - -5 . 4 2-3 2-3 3 4--5 4-5 6 34 5 6 43 i 2 4. 1-2 1-2 3 *Not comparable. tower the upper system may be shut off.and a secondary distribution system put in service midway down the height of the tower. The water will be kept above freezing because it will have shorter contact with the air. The mechanical draft tower can be protected by reducing the air flow through the tower, by stopping or reducing the speed of the fans, or by partially closing dampers. ' If the system is.operated intermittently;in freezing weather, water in the basin may freeze and the expansion of the ice may do harm. Freezing during intermittent operation can be prevented only by draining the water basin when it is out of service. On small roof installations, a tank large enough to hold all the water in the system is often installed inside the building and the basin is drained into this by gravity, the pump suc tion being taken from this inside tank. . . ; : A comparison of various types of-xwater cooling equipment is given in Table 4. ' APPARATUS FOR INDUSTRIAL CONDITIONING Apparatus for industrial air conditioning may be divided into two distinct groups, namely, (1) humidifiers for increasing the moisture con tent of the air and for producing cooling by evaporation and (2) dehu midifiers for removing moisture from the air and for producing cooling by contact with water or surfaces at a lower temperature than the air. Strictly speaking, humidity control alone, whether it involves humidi fication or dehumidification, is not air conditioning. To be entitled to this classiftcation.according to the definition in Chapter 44, the'process should include the simultaneous control of temperature, humidify and air motion. 212 Chapter 11--Humidification and DehumidificatiOn Industrial humidifiers may be divided into the following. general types, according to the method of operation: : 1. Direct, which spray into the room.. . 2. Indirect, which introduce moistened air. 3. Combined direct and indirect. . ._ . Spray Generation . Spray generation is obtained by (I) atomization, (2) impact, (3) hydraulic separation, and (4) mechanical separation, . . Atomization involves the use of a compressed air jet to reduce the water oarticles to a fine spray. With the impact method, a jet of water under oressure impinges directly on the end of a small found wire. Where hydraulic separation is employed, a jet of water enters a cylindrical chamber and escapes through an axial port with a rapid rotation which causes it immediately to separate in a fine cone-shaped spray. In the mechanical separation process, water is thrown by centrifugal force from the surface of a rapidly revolving disc and separates into particles suf ficiently 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) atomizing, (2) high-duty, (3) spray and (4) self-contained or centrifugal. Atomizing Humidifiers There are several types of atomizing humidifiers, all of which rely upon compressed air as the atomizing and distributing agency, similar to the familiar method used in ordinary nasal atomizers. Compressed air (ordinarily about 30 lb per square -inch) is supplied from a centrallylocated air compressor through pipe lines to the atomizing units. The air lines are usually horizontal and parallel to water lines which supply water by gravity from a float tank. The water in the tank is maintained at a constant level slightly lower than the outlets of the atomizers them selves and is drawn constantly to the atomizer by aspiration when comr pressed air is supplied. This aspiration ceases and the flow of water stops when the air supply is cut off. The water should not be supplied under pressure to atomizers because of the possibility of leakage, drip, or coarse spray which cannot be permitted when water is supplied by aspiration. High-Duty Humidifiers Water is supplied to high-duty humidifiers under high pressure (usually about 150 lb per square inch) through pipe lines from a centrally-located 213 American Society of Heating and Ventilating Engineers Guide, 1936 pumping unit. The spray-generating nozzle which is of the impact type is located in a cylindrical casing. A drainage pan provides for the collec tion 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 to the wet-bulb temperature. It then escapes from the opening below at a high velocity in a complete and nearly horizontal circle. The spray is quickly evaporated and the resulting vapor is rapidly and thoroughly diffused. This effective distribution of fine spray over the maximum possible-area insures complete and extremely rapid vapori zation even at the highest humidities. Spray Humidifiers . . This type of humidifier consists of an impact spray nozzle in a cylin drical casing with a drainage pan below it. The aspirating effect of the spray nozzle induces a moderate air current- through the casing which distributes 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. The spray and high-duty types of humidifiers have many features in common but the latter, because of its finer spray and greater Capacity, is often considered better adapted for producing high humidities. Self-Contained Humidifiers . . The self-contained or centrifugal humidifier 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 provided to permit the cleaning and.servicing of individual units without affecting the room as a whole, group control of the water and power may be employed. Where large quantities of power are generated in a limited space and where a comparatively high relative humidity is required, it is often feasible and economical to use a. combination of direct and indirect humidification. The indirect humidification provides the desired quantity of ventilation and cooling, and the additional direct humidification pro* vides for increase in humidity without.interfering with the ventilation or the cooling effected by the indirect system. In general, it may be stated that direct humidification is most, satis factory where high humidities are desired but where, little cooling, ven tilation or air motion is required. Therefore, the indirect system is most applicable where either low or high relative humidities are desired with maximum cooling and ventilation effect- For conditions that require an unusually large amount of heat to be absorbed by ventilation, together with the maintenance of high humidities, it is often preferable to-make use of the combination system of indirect and direct humidification. If . the indirect system alone were used it would mean an unusually large' volume of air to be handled, which might interfere, due to air motion, with production, even though it would result in greater cooling effect. If direct humidification alone were used, no ventilation would be obtained, with consequently higher room. temperatures. , 214 Chapter 11- Humidification and Dehumidification PROBLEMS IN PRACTICE ..mine the per cent saturating efficiency of an air washer used for 1 V saturation or evaporative cooling if the following temperatures are obtained on the entering and leaving sides of the washer: ' Lwring air, 84.3 F dry-bulb and 71.2 F wet-bulb. Leaving air, 73.4 F dry-bulb and 71.2 F wet-bulb. The equation for determining saturation efficiency is: ,, (db, - nib,) - (db, - wb,) lnn where E = saturation efficiency in per cent. db, = dry-bulb temperature of entering air. jfjhi = wet-bulb temperature of entenng air. db. = dry-bulb temperature of leaving air. wbj = wet-bulb temperature of leaving air. Therefore = (gjj ~7TMl ~ nt ~ 71'2~ x 100 = Hr x 100 "832percent- 2 How may relative humidity be controlled? a. If constant room temperature is to be maintained: 1. To maintain a constant relative humidity, the dew point must be kept constant. 2. To increase the relative humidity, the dew point must be raised: 3. To decrease the relative humidity, the dew point must be lowered. , b. If constant dew point is to be maintained: 1. To maintain a constant relative, humidity, the room temperature must remain constant. . - . 2. To increase the relative humidity, the room temperature must be lowered. 3. To decrease the relative humidity, the room temperature must be raised. 1' c. With varying dew-point temperatures: 1. To maintain a constant relative humidity, the room temperature must vary directly and in almost equal amount with the dew point. 2. To increase the relative humidity, the difference between room temperature and dew point must be decreased. . . 3. To decrease the relative humidity, the difference between room temperature and dew point must be increased. ' . d. With varying room temperatures: .. 1. To maintain a constant relative humidity, the dew point must, vary directly.and in almost equal amount with the room temperature. . 2. To increase the relative humidity, the difference between dew point and room temperature must be decreased. 3. To decrease the relative humidity, the. difference between dew point-and room temperature must be increased. 3 In industrial air conditioning plants, what are the four sources of heat which must.be taken into consideration in the.design of a system? . . a. Heat transfer from the outside air. J. Body heat from employees. c. Sun effect. d. Heat equivalent of power consumed in driving machinery, in lighting, and in manu facturing processes in general. - 215 American Society of Heating and Ventilating Engineers Guide, 1936 4 Why do cooling towers give best results when, the humidity of the air is low? The cooling of water by dropping it through air depends mostly upon the evaporation of the water. If the relative humidity of the air is low, the water vapor will be readily absorbed and carried away, while if the humidity of the air is high, its capacity to pick up water vapor is less and the water is cooled less with the same exposure to air. 5 0 What performance tests' should be given air washers? a. Capacity. b. Resistance. c. Visible entrainment of free moisture. d. Humidifying efficiency. e. Cleaning effect. . ' ' . 6 0 What are the several different types of water-cooling towers? a. Those with forced draft. b. Those with natural draft open to the atmosphere. c. Those with natural draft closed to the atmosphere. d. Those with combined natural and forced draft. . .. .. 7 # What are the different types of air washers? a. Spray, b. Wet scrubber, c. Combination spray and scrubber. 8 0 What is the saturation efficiency for an air washer with the common variations in spray arrangement? .. For three banks, two up-stream and one down-stream............................ 100% For two banks, both up-stream...................................................................... .. 95% For two banks, one up-stream and one down-stream................ ............... 85% For one bank, up-stream................................................................1....._______....... 80% For one bank, down-stream........................... ....... ............. ............................... 65% 9 # Upon what air velocity are air washers usually rated? 500 fpm, through the area above the tank. . 10 0 What wet-bulb temperature for the outside air is usually selected in air . conditioning design when cooling is to be accomplished? One which is not exceeded more than 5 to 8 per cent of the time in the locality where the plant is to be situated. . _ 11 9 Where should the suction, connection -be placed in a cooling pond? As far below the surface as possible and as far away from the discharge as practicable? 12 9 What chemical is used to kill algae formations in spray ponds? Potassium permanganate. ' '. ' . 13 0 What is the usual amount of spray water delivered to a cooling pond per square foot of pond area? '' ' ! : From 0.1 gpm on small sizes to 0.8 gpm on large sizes. 14 0 What is the usual amount of water delivered in cooling towers per square foot of area? From 0.6 to 1.5 gpm. ' .- 15 0 About how much water is lost by evaporation in atmospheric cooling? About 1 gal per 1000 gal for each degree of cooling range. 16 0 How is freezing obviated in cooling pond sprays? '' The pressure and quantity of water is lowered so that the drops become of increased size and do not freeze so readily. . 216 Chapter 12 UNIT HEATERS, VENTILATORS, COOLERS, AND AIR CONDITIONERS Classification of Unitary Equipment and Related Systems, Advantages, Uses, Functions, Types of Construction, Locations, Capacities, and Accessories to Unitary Equipment IN other chapters, complete descriptions have been given of heating, cooling, ventilating, humidifying, and dehumidifying systems. These descriptions have covered the detailed principles of each and have, in general, described the assembled equipment that has been used to make these the complete systems. The success of such completely engineered, heating, cooling, and air conditioning systems has inevitably lead to the production of smaller factory^assembled equipment employing a majority of the principles of these complete systems. As a result, present day practice involves the use of this unitary equipment in the majority of smaller installations where capacity demands are within the limits of such units. Thus unit heaters,. unit ventilators, unit coolers, and unit com ditioners have come to occupy a place of their own in the industry. With the growth of this unitary industry, it becomes increasingly evident that there is no sharp line.of demarcation, on the basis of capacity, between a unit and a so-called central station system. The various in dustrial codes have thus found it necessary to describe a unit as a factorymade encased assembly, shipped substantially complete, or built and shipped in sections so that the only field work necessary is the assembling together of the;sections, without resorting to any field fabrication. These units consist of assemblies of functional elements indicated by their names, such as Air Conditioning Unit, Room. Cooling Unit, Humidifying Unit, etc. A unit such as defined may be complete in itself, employing its own direct means of air distribution and sources of refrigeration or heating, in which case, it thus represents a Complete self-contained unit system. Or it may be coupled with separate means of air distribution such as duct work and outlets, in which case, it will still be considered as a unit system, in distinction to the generally accepted term of a. field fabricated central station system. The manufacturer of the ,,unit is responsible for the output and performance of the unit under rated conditions, whereas the contractor installing the complete unitary system is normally held responsible for the complete performance of the system. 217 ofAmerican Society Heating and Ventilating Engineers Guide, 1936 Unit equipment as described previously justifies its existence due to the following features: . . 1. Lower cost per unit capacity. Standardized design and volume production makes possible low cost factory assembly thereby eliminating individual design and handling of every part for each installation. 2. Flexibility and mobility of equipment. Unitary equipment can be readily located in existing buildings without the neces sity of running large ducts through floors and many partitions. Such equipment can be shifted to meet changing requirements. Tenants may obtain the advantages of , conditioning when the entire building is not equipped with a conditioning system. In industrial process work, the flexibility of unitary equipment is of great advantage. 3. Lower installation costs. . The fact that the equipment arrives on the job in an assembled condition, coupled with the lesser problems of duct work and connecting piping, materially reduces installation costs. 4. Small capacities. The small capacities available in unitary equipment have brought the advantages of controlled air conditions to a number of small offices, stores, shops, and individual rooms where specially designed and built central system equipment would have been uneconomic. . This chapter will limit itself in general to a description and discussion of the functions and construction of the units themselves indicating the accessory features necessary to complete unitary systems. SUB-DIVISION OF UNITARY EQUIPMENT While for descriptive purposes, it would be better to sub-divide unitary equipment on a purely functional basis, such as heating, cooling, venti lating, etc., there has grown up very definite branches of this industry in which the engineering. and application of the equipment vary quite widely. Thus common acceptance in the industry recognizes the following sub-divisions: ...... 1. Unit heaters consisting of an encased heating surface through' which air is forced by means of a fan or blower, located either in or closely adjacent to'the heated : . space, and normally employed only for industrial and commercial applications. 2.. Unit Ventilators which are similar in principle to unit heaters but are designed ` to use outside air with or without provision, for recirculation of the air. While unit heaters are largely used for commercial and industrial applications* unit ventilators are intended primarily for school, offices and semi-commercial applications. . 3. Unit Coolers which are similar to unit heaters except that a cooling medium is used in place of a heating medium and provision is made to catch and remove the condensate. A distinction is made here between unit coolers, normally applied to the- cooling of products for their preservation or processing, and unit conditioners used for cooling for comfort. . ,,. . . 4. Unit Conditioners which consist of equipment to provide control of heating with humidifying, or cooling with dehumidifying, coupled with air circulation/all com pactly housed in a single casing. . 5. Miscellaneous Unit Equipment and Accessories such as- filtering equipment, attic fans, humidifying units and special controls. These sub-divisions will be discussed in detail. 218 ` i2^Unit Heaters, Ventilators, Coolers, and Air Conditioners UNIT HEATERS A unit heater consists of the combination of a heating element and fan blower having a common enclosure and placed within or adjacent to the space to be heated. Generally no ducts are attached to inlets or tn tlets although, it is common practice with many unit heaters to equip them with directional outlets or adjustable louvers. While unit heaters ere first applied to industrial heating, the constant development and morovement of this equipment both as to appearance and quietness has broadened its field of application until today unit heaters are available for fields extending from large factory spaces to recreation rooms, churches, and offices. While unit heaters are designed primarily to handle all recirculated air, they may be installed to handle either partial or total out-door air. Compared with the older method of heating by means of radiation, properly designed and applied unit heaters should: 1. Circulate air in the building at a rapid rate but without objectionable draft. 2. Reduce the temperature differential between the floor and ceiling. 3. Direct the heated air so that uniform temperature distribution be obtained throughout the heated space. 4. Prevent or remove the cold stratum of air commonly found at the floor level. 5. Reduce the number of heating elements required and thereby decrease the cost and extent of the piping necessary. 6. Maintain a closer control of room temperature either manually or by means of simple thermostats. 7. Produce an economy in heating costs resulting from the sum total of the above advantages. TYPES OF UNITS A wide variety of types of unit heaters is available. They all employ some form of convector, supplied with either steam or hot water, although occasionally equipped for gas or electric heat. Air is always forced over these convectors by a fan of either the propellor or centrifugal type. Heating surfaces may be in the form of steel pipe coils, non-ferrous tubes or pipes with extended surfaces, cast iron, and pressed or built up sections of the cartridge or automotive type. Two major sub-divisions of design are commonly recognized. Floor mounted units which withdraw the cold air from the floor and discharge the heated air above the working zone and the suspended type where the unit is located in an elevated position withdrawing the air from this level and discharging the heated air down into the working zone. In closely occupied spaces where direct air drafts into the. working zone are not permitted, the floor mounted unit will give more uniform temperature distribution. On the other hand if opportunity is provided to deliver the heated air from suspended units down into the working zone excellent temperature distribution is possible. Housed fan, high velocity discharge units with outlets adjustable to deliver air in several directions are able to project their heating effect over distances of. from.30 ft to as much as 200 ft front the unit. This makes possible the location of these units at considerable distances from each 219 American Society of Heating and Ventilating Engineers' Guide, 1936 7HT Fig. 1,, Suspended Unit Heater, Propeller Type Fan 'q^^ter 12--Unit Heaters, Ventilators, (Coolers, and Air Conditioners ther thus greatly reducing the piping and loss of floor space as a result f the heating equipment. Propellor-type fan units with outlet velocities of from 300 to 1000 fpm are usually placed from 30 up to 100 ft apart. Fig. 1 shows a typical suspended typp unit heater with propellor type fan. Fig. 2 illustrates a' typical floor mounted type unit heater with byoass feature. Such units are available either "with, or without this air by-pass. For purposes of this control feature see Chapter 14. Fig. 3 shows suspended high-velocity type unit heater connected to outside air intake with damper to control volume of ventilation. HEATING MEDIUM The convectors of unit heaters or ventilators may be supplied with either hot water or steam. When water is used, it should be circulated mechanically and the pump rate and friction loss should be based upon test data for the particular unit to be employed; Normally the friction within the convector is too great for gravity circulation. The heat output of a given heater will normally be less when using water than with steam at the same temperature, unless high rates of circulation are maintained. Either high or low pressure steam may be used but it is essential that proper venting of the air from the coil be: obtained at all times.; Where unit heaters are used with outside air in freezing climates, it is unwise to use steam of less than 5 lb pressure at the coil, due to the possible danger of freezing of condensate in the tubes.' It is essential that properly constructed traps and some form of thermostatic air by-pass be used with high pressure steam as well as adequate condensing legs to prevent steam in the returns. Increasing the return temperature tends to increase return line corrosion, especially at points where overheated condensate or steam enters the return line.' .. :, ' ' When low pressure steam is used with unit heaters and ventilating units, it is important that proper means be provided for the removal of the heavy condensation. Such units should not be applied to low pressure gravity return systems except where the difference in heater level and boiler water line is large enough to compensate for the pressure loss through the convector at its highest condensation rate. The use of vacuum or return punips and receivers is advisable with jobs of any considerable size, as the best method of taking care of the condensate and at the same time providing for proper venting of the units directly into a vacuum return line system, pr into an open vented return system, the latter having some advantage in preventing the formation of any vacuum in the unit itself, which sometimes tends to hold up condensate and causes freezing. ESTIMATING HEAT LOSSES The heat losses of a building to be equipped with unit heaters are determined in the same manner as for any other heating system, excepting so far as the unit heaters may prevent air stratification and thus reduce the temperature difference between the ceiling and floor. (See Chapter-7.) . Unit heaters may be arranged,to recirculate the air or to supply warmed air from the outside for ventilation or to make up air exhausted. 221 of andAmerican Society Heating Ventilating Engineers Guide, 1936 If all or a part of the air is to be taken in from out-of-doors, the heat necessary to warm this air from the outside temperature to the inside temperature must be added to the transmission or other losses. Units of the number and size needed to furnish the total heat required are then selected from the manufacturers' rating tables, using these ratings at the steam pressure to be used and at the temperature at which the air will enter the convector. . . AIR TEMPERATURES1 For recirculating heaters with intakes at the floor level, the temperature to be maintained in the room should be considered as the temperature of the air entering the heater. Where outside air is introduced, the tem perature of the mixture must be calculated and used as the entering air temperature to the heater. Where suspended heaters are used without any intake boxes extending down to the floor level, a higher entering air temperature should be used than that at which the room is to be main tained. .. With suspended unit heaters taking air at some distance above the floor, the temperature variation from floor to ceiling may reach as much as 1 deg for each foot of elevation during the periods when the maximum capacity of the heaters is required. Thus this allowance should be made in calculating the capacity of suspended heaters. Unit heaters taking in recirculated air at the floor level should maintain temperature differentials of less than 0.5 deg per foot of elevation when the maximum capacity of the heaters is required. This temperature difference per foot of elevation is less than the corresponding variations for spaces heated by direct radiation. Unit heaters save fuel because of their ability to circulate air at a lower average temperature than the air circulated by direct radiators; however, the unit heaters must circulate more air in any given time than is needed with direct radiators. This requires the selection of heaters having a liberal air capacity for the required heat output, which in turn means a relatively low final temperature. Extremely low final temperatures can be had only at the expense of larger heaters and increased power, so that an economic limit is imposed. In general, for heating purposes it is advisable to use a delivery temperature not more than 70 F above the average room temperature desired, and considerably less where possible. Since the delivery temperature increases with increase in steam pressure with high pressure steam, units should be selected that have a minimum heating surface in order to provide outlet air not in excess of 70 F above average room temperature. . - - OUTPUT OF HEATERS It is standard practice to rate unit heaters in Btu pet hour at a given temperature of air entering the heater and at a given steam pressure maintained in the coil. Steam at 2 lb pressure and air entering at 60 F ' ^Temperature Gradient Observations in a Large Heated Space, by G. L. Larson. D. W. Nelson, and O. ,C. Cromer (A.S.H.V.E. Transactions, Vol. 39, 1933). . 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. Journal Section, Heating, Piping and Air Conditioning, November. 1934). 222 'Chapter 12--Unit Heaters, Ventilators, Coolers, and Air Conditioners used as the standard basis of rating2. The capacity of a heater ?r eases as the steam pressure increases, and decreases as the entering `"c temperature increases. The heat capacity for any condition of steam 3ressure and entering air temperature may be calculated approximately f om any given rating by the use of factors in Tables 1 and 2. Table 1 for blow-through and Table 2 is for draw-through unit heaters. These tables are accurate within 5 per cent. The ratings customarily published for unit heaters apply only for circulation and free discharge, unless otherwise noted in the rating tables. If outside air intakes, filters, or ducts on the discharge side are used with the heater, proper, consideration should be given to the reduc tion in air and heat capacity that 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 employed, so that no specific percentage of reduction can be assigned for all heaters for a given added resistance. In general, however, disc or propeller fan units will have a larger reduction in capacity than housed fan units for a given added resistance, and a given heater will have a larger reduction in capacity as the fan speed is lowered. When confronted with this problem the ratings under the conditions expected should be secured from the manufacturer. When steam supplied to the heaters contains superheat, the capacity of the heater will be but slightly less than with saturated steam at the same pressure. Recent tests indicate that the reduction of capacity from this cause is negligible for superheat up to 50 deg and will not exceed V/2 per cent for any degree of superheat. DIRECTION OF DISCHARGE Heaters may be distributed through the central portions of a room discharging toward exposed surfaces, or may be spaced around the walls, discharging along the walls and inward as well, especially when there are considerable roof losses. . In general, it is better to direct the discharge from the unit heaters in such fashion that rotational circulation of the entire room content is set up by the system rather than to have the heaters discharge at random and in counter directions. . _ _ Various types and makes of unit heaters are illustrated in the Catalog Section of this edition. Usually hot blasts of air in working zones are objectionable, so 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 shall be brought as close to the head line as possible, yet not into the working zone. In general, the higher the elevation of the unit, the greater the volume and velocity required to bring the warm air down to the working zone> and conse quently, the lower the required temperature of the air leaving the unit. *See A.S.H.V.E. Standard Code for Testing and Rating Steam Unit Heaters (A.S.H.V.E. Trans actions. Vol. 36, 1930). 223 of andAmerican Society Heating Ventilating Engineers Guide, 1936 BOILER CAPACITY ` The capacity of the boiler should be based on the rated capacity of the heaters at the lowest entering air temperature that will occur, plus an allowance for line losses. Ordinarily for recirculating heaters the lowest entering temperature will occur at the beginning of the heating period and is usually taken as 40 F, while for ventilators taking air from outdoors the lowest entering temperature will be the extreme outdoor temperature expected in the district. No greater allowance in boiler capacity beyond the calculated heat demand need be added in order to supply unit heaters than for any other type of system. It is unwise to install a single unit heater as the sole load on any boiler, particularly if the unit heater motor is started and stopped by thermostatic control. The wide and sudden fluctuations of load that occur under such conditions would require closer attendance to the boiler than is usually possible in a small installation. Where oil or gas is used to fire the boiler, it is possible by means of a pressurestat to control the boiler, in response to this rapid fluctuation. In most cases, however, and particularly where the boiler is coal-fired, it is advisable to use two or more smaller heating units instead of one large unit. Steam pressures below 5 lb can be used with safety for recirculating unit heaters when their coils are designed for the purpose and when proper provision is made for returning the condensate. If ventilators are to take in air that may be at a temperature below freezing, however, a steam pressure of not less than 5 lb should be maintained on the convector or a corresponding differential in pressure between the supply and returns be maintained by means of a vacuum. QUIETNESS In selecting unit heaters, attention should be given to the degree of quietness required for the installation. No given fan speed may be applied as a measure of relative quietness to fans of different designs and proportions. Quietness is a function of' type, diameter, blade form and other variables besides speed, and all these must be taken into account. In general small fans may be run at higher motor speeds than large fans with equal quietness; and centrifugal fans are more easily made quiet than disc or propeller fans. \ PIPING CONNECTIONS Piping connections for unit heaters are similar to those for other types of fan-blast heaters. Typical connections are shown in Figs. 4 and 5. One-pipe gravity and vapor systems are not recommended for unit heater work. . .' 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. Pressuredrop must be compensated for by elevation of the heater above the water line of the boiler or of the receiver. In pump and receiver systems the air may be eliminated by individual 226 12--Chapter Unit Heaters, Ventilators, Coolers, and Air Conditioners air valves on the heaters, or it may be carried into the returns the same as for vacuum systems and the entire return system be free-vented to the atmosphere, provided all units, drip points, and radiation are properly trapped to prevent steam entering the returns. On vacuum or open vented 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 heavyduty trap for handling both the condensation and the air, provided the air finally can be eliminated 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 the unit, a Fig. 4. Unit Heater Connections Where Condensation Is Returned to Vacuum Pump or to an Open Vented Receiver _ _,, T, ' ?g- Unit Heater Connections Where Condensation Is Returned to Boiler Through Wet Return high pressure air valve can be used; otherwise-the air may be passed with the condensate through the high-pressure return trap, with some danger of return pipe corrosion and the problem of its elimination at some other point in the system. The connections for steam and return piping to unit heaters must always be calculated on the basis of the high heat emission or condensation rate of such devices. The pipe-size tables given in Chapter 32 may be used for unit heater work by multiplying EDR values by 240 to get Btu values. ' All Electric OTHER TYPES OF UNITS The foregoing discussion relates generally to units in which steam or hot water is used as the heating medium. On rare occasions electrical resistances are used as the heating element. These are applied only where electric power is abundant and cheap and where other forms of fuel are scarce and expensive. (See Chapter 39.) Direct Fired A recent development in gas burning equipment is the direct-fired industrial unit heater. These heaters are of the warm-air type and are 227 American Society of Heating and Ventilating Engineers Guide, 1936 equipped with fans which cause the air to pass over the heating surfaces at a fairly high velocity and then direct the warm air in to the space to-be heated. As is the case with the steam-fed unit heaters, the gas-fired appliances may be used for heating stores, shops, and warehouses. They usually are suspended in the space, to .be heated and in most instances leave the entire floor and wall area free for commercial use. Partial, or complete automatic control also may be secured on appliances of this type. . This type of heater is often used for temporary heat during building construction or where the installation of. a. steam or hot water plant is for some reason not justified. For permanent installations, it is usually advisable to provide an exhaust duct from the gas-fired unit heaters to remove products of combustion from the occupied space. While this is not necessary in large open industrial plants, in smaller closed rooms, it becomes essential. Turbine Driven . Where high pressure steam is available it is sometimes used to drive a steam turbine direct-connected to the unit heater. The exhaust from this turbine, reduced in pressure, is then passed into the heating coil where it is condensed and returned to the boiler. INDUSTRIAL USES In addition to their prime function of heating buildings,. unit heaters may be adapted to a number of industrial processes, such as drying and curing, with 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 given off. When such conditions are severe, it is necessary that the heaters draw air from outside in enough volume to provide a rapid air change arid that they operate in conjunction with ventilators or fans for exhausting the moisture-laden air. (See discussion of condensation in Chapter 7.) :. Information on the control of unit heaters will be found iri Chapter 14. . ,r UNIT VENTILATORS3 Unit ventilators while designed primarily for ventilation must incor porate controlled heating. Since these units are generally located in the occupied space, they must be pleasing in: design and must harmonize with the furniture or with the decorative scheme. A typical unit venti lator .is illustrated in Fig. 6, They usually consist of a semi-decorative cabinet containing the following necessary or optional parts: -. 1." Outside air inlet.. . ' . .. . . ., 2. Inlet damper for closing the opening to the outside air inlet when the unit is not in use. . ' .. 3. Adhesive or dry type filters for cleaning the air (optional). .. , *A roof ventilator is'sometimes termed a unit ventilator. Fot information on roof 'ventilators, see Chapter 12--Unit Heaters, Ventilators, Coolers, and Air Conditioners . Fic. 6. Typical Unit Ventilator Showing One of Many Arrangements of Dampers and Heating Coils , 4. A heating element usually of special design and intended for low pressure steam. 5. Motor and fan assembly. .. . 6. Mixing chamber where warm and cold air streams are brought together. (No mixing chamber is normally provided, where sectional type convectors are used.) 7. Outdoor air inlet and recirculating air mixing damper (optional). .- 8. Device for ozonizing air (optional). 9. Discharge grille or diffuser. .. . 10. Temperature control arrangement. .; . The primary functions of a unit ventilator are: 1. To supply a given quantity of outdoor air for ventilation or to mix indoor and outdoor air. . . ." 2. To warm the air to approximately the room temperature if the unit is intended for ventilation only, or to a higher temperature if it is intended to take care of all or a part of the heat transmission fosses from the room. 3. To control the temperature of the air delivered so as to prevent both cold drafts and overheating. .. ;. 4. To deliver air to the room in such a manner that proper distribution is. obtained without drafts. . . , 5.-To recirculate room air for the purpose of heating or promoting comfort when ventilation is unnecessary. . 6. To perform all its functions without objectionable noise. In addition to these functions, unit ventilators frequently are arranged so that the air supplied may be cleaned by riieans of filters of either the dry or viscous type. If filters are used, the proper allowance must be made for the increased resistance offered to the air flow. Humidifiers iri unit veritilatbre are rather difficult to control and are only furnished upon special order. . : .. V Supply for Ventilation. - The outdoor air supply for ventilation delivered by motor-driven fans operated at comparatively low-speeds; the back of the cabinet being connected to the outside through rust-proof . . 229 ofAmerican Society Heating and Ventilating Engineers Guide, 1936 louvers and screens. Air quantities may be estimated on the basis of data given in Chapter 3. (See A.S.H.V.E. Ventilation Standards.) 2. Warming Incoming Air. The air is heated by passing it through specially designed convectors. The amount of heating surface to be provided in the unit is determined by the volume of air to be heated and the temperature range. If the unit is to be used for supplying air for ventilation only, the convector must be sufficient in capacity to maintain a final air temperature of about 70 F. If the unit is to be used for heating as well as for ventilation, the convector must be sufficient to maintain the necessary final air temperature for the conditions involved. . 3. Control of Temperature. This is accomplished by varying the tem perature of the air discharged from the unit (1) by the automatic opera tion of a mixing damper which controls the relative quantities of air being blown through the heating unit or by-passed around it, (2) by operation of valves on different layers of convector surfaces, or (3) by variation in the temperature of the circulating heating medium. The outside air inlet damper and recirculating damper (where one is provided) should be so connected that there will be an uninterrupted supply of air to the fans at all times the unit is in operation. These dampers may be operated by hand or by pneumatic or electric motors manually controlled from some central point. These dampers may also be linked together, in the form of mixing dampers and be controlled by a thermostat in the cold air intake, by a differential thermostat acted upon by both the cold air and the recircu lated air, or by a thermostat in the two streams of air after they are mixed, so as to keep the relative proportion of air taken in from out-of doors commensurate with outside temperatures and to prevent drafts of cold air being blown through the unit into the room. ' Provision should be made for the inlet damper to close automatically whenever the fans are shut down, and not to open until the room is properly heated when the fans are again started. The minimum tem perature of the air delivered by the machine should be regulated auto matically by a thermostat in the outlet air which controls the temperature of the heated convector, or this minimum temperature may. be main tained by properly mixing the inside and outside air by means of the mixing dampers under thermostatic control referred to above. Another thermostat in the recirculated air intake to the unit or elsewhere in the room controls by-pass dampers or the supply of heating medium, or. both, so as to control the temperature of the air leaving the unit according to the heat requirements of the room. In addition to these thermostats, a room thermostat is needed to control any other heat sources for the room. (See Chapter 14.) . Thermostats for controlling by-pass dampers must be of the inter mediate type to hold the dampers in intermediate positions to prevent objectionable drafts. When direct radiators are used in conjunction with unit ventilators, the control is usually arranged so as automatically to open the valves to the direct radiators' when the room temperature falls about 2 deg below the setting of the thermostat for the unit ventilator. Another arrangement opens the radiator valve whenever the unit venti- lator control reaches the full heating position. Further information on this subject is contained in Chapter 14. s { f 230 2 12--Unit Heaters, Ventilators, Coolers, and Air Conditioners 4 Distribution. This function is governed by the proper selection and 1 cation of the unit. Diffusion and distribution are dependent upon a relatively high velocity air stream discharged in a generally vertical direction, and in order to insure satisfactory diffusion in the room the less the difference between the temperature of the air discharged from the unit and that of the room air, the better. With a final temperature above 110 F, excessive stratification of the air may be experienced. Trouble some drafts may be eliminated to a large extent if a static pressure is built up in the room. 5 Recirculation of air requires less fuel than does the use of all out side air and aids in heating up quickly. Certain units are designed to recirculate all air at all times, except when the admission of outside air is needed to regulate room temperatures. Under this arrangement, the outside air for ventilating purposes is obtained solely from infiltration, but the amount thus obtained may or may not be sufficient to meet legal ventilating requirements for public buildings. Recirculation of the air in schools is therefore prohibited by ordinance in many communities. Ventilating systems in schools should be arranged for taking in a suf ficient quantity of air to constitute, with infiltration, not less than 10 cfm per occupant of a room. . 6. Quiet Operation. Since the unit ventilator is generally set in close proximity to the room occupants, it must operate with exceeding quietness. SPLIT AND COMBINED SYSTEMS In a split system the unit is used primarily for ventilation. Air is delivered to the room at very near the room temperature, and enough separate direct heaters are placed in the room to warm it to the desired temperature, independently of the unit. Their principal advantage lies in offsetting the cooling effect of window and wall surfaces long before these can be heated to room temperature and in retaining heat for this purpose after the ventilation is shut down. Where the unit ventilator selected has a capacity more than sufficient to warm the air needed to meet the ventilating requirements, a cor responding reduction may be made in the amount of direct heating surface installed. The greater the amount of excess capacity of the unit, the more efficient will be the temperature regulation of the room. The split system permits the heating of the room during failure of electric current, since the direct radiators will furnish heat, but it permits a careless operator to avoid operating the ventilating equipment. A combined system employs the unit ventilator alone, its capacity being sufficient both for ventilation and for supplying the heat loss. Direct heating surface is omitted altogether. It becomes necessary then that the fan be running whenever the room is to be heated but this also gives assurance of ventilation, especially if automatic dampers are used in the air intake from out-of-doors and in the recirculating intake arranged so as to give a certain quantity of air from the outside (commensurate with weather conditions) whenever the unit is operating and after the room is heated. The cost of installation of a combined system is usually less than that of a split system and there is less danger of overheating, but if the electric energy fails there will be practically no heating. American Society of Heating and Ventilating Engineers Guide, 1936 LOCATION OF UNIT The location of the unit ventilator in a room is important. Wherever possible it should be placed against an outside wall. It is difficult to obtain proper air distribution if the unit is erected either on an inside wall or in a corner of the room. Standard units discharge the air stream up-, ward, but for special cases units may be installed to discharge air hori zontally., Units may be set away from the wall or partially recessed into the wall to save space without materially affecting the results. The air inlet may enter the cabinet at the back at any point from top to bottom. ' VENTS4 . The size and location of the vent outlet is important. In many cases the sizes for public buildings are regulated by law, but the location of the vents generally is left to the discretion of the engineer. Best results have been obtained with a velocity through the vent openings 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. The cross-sectional area of the vent flue itself may be figured on the basis of 15 sq in. of flue for each 100 cfm. Thus the vent flue area of a flue for a room equipped with one 1200 cfm unit ventilating machine would be 180 sq in. The area of vent flue opening from the room ,may be figured on the basis of 25 sq in. per 100 cfm. In school buildings provided with wardrobes or cloakrooms the vents, may be so located that the air shall pass through these spaces, heating and ventilating them with air which otherwise would be passed to the outside without being used to the best advantage. Many state codes for venti lation of public buildings make this arrangement mandatory. There has been much controversy over the use of corridor ventilation in school building practice, one group holding the view that when each classroom has a separate vent flue there is a minimum ,fire risk arid less likelihood of cross-contamination, while others emphasize the economy features of the corridor discharge and minimize the fire, contamination, and other hazards. CAPACITIES Unit ventilators are available in air capacities ranging from 450 cfm to 5000 cfm and with corresponding heat capacities (above that required for ventilation purposes based upon an outside temperature of zero and an inside temperature of 70 F) ranging.from 30 Mbh to 144 Mbh (1 Mbh = 1000 .Btu per hour). Some manufacturers furnish a unit with several heating capacities for each air capacity, thus enabling the engineer to select the unit best adapted to the heating and ventilating load. Capad- ^Investigation of Air Outlets in Class Room Ventilation, by G. L: -Larson, D. W. Nelson, and R.,W. Kubasta (A.SIH.V.E. Transactions, Vob 38, 1932)., . ....................... 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. Journal Section, Heating, Piping and Air Conditioning, June, 1935). 232 Chapter 12--Unit Heaters, Ventilators, Coolers, and Air Conditioners ties should be determined in accordance with the A.S.H.V.E. Standard Code for Testing and Rating Steam Unit Ventilators6. Typical capacities are given in Table 3. The amount of heat to be supplied by the unit ventilator will depend on the amount of air passed through the unit and the temperature range through which the air is heated. The weight of air (W) to be circulated per hour is fixed by the ventilating requirements. If no direct heating surface (radiation) is installed, the combined heating and ventilating requirements must be taken care of by the unit ventilators, and the total heat to be supplied is obtained by means of the following formulae: When all of the air handled by the unit is taken from the outside, Ht = 0.24 W(ty- t0) (l) W = d 60 Q (2) where ty = H 0.24 W + 1 (3) d = density of air, pounds per cubic foot. H = heat loss of room, Btu per hour. Hy = heat required to warm air for ventilation, Btu per hour. Ht = total heat requirements for both heating and ventilation, Btu per hour = H + Hy. ' Q - volume of air handled by the ventilating equipment, cubic feet per minute. t = temperature to be maintained in the room. t0 = outside temperature. ty = temperature of the air leaving the unit. . W = weight of air circulated, pounds per hour. 0.24 - specific heat of air at constant pressure. . From Equations 1, 2 and 3: Ht = H + 0.24 d60 Q (t -- to) (4) Example 1. The heat loss of a certain room is 24,000 Btu per hour, and the ventilating requirements are 1000 cfm. If the room temperature is to be 70 F and all air is taken from the outside at zero, what will be the total heat demand on the unit if it is required to provide for both the heating and ventilating requirements (combined system)? Solution. H = 24,000; d = 0.075 Q = 1000 cfm; t = 70 F; <o = 0 F. . Substituting in Equation 4: Ht = 24,000 + 0.24 X 0.075 X 60 X 1000 (70-0) = 99,600 Btu ty = ----- :ffe'OOOL 70 -- 92 2 F * 0.24 X 0.075 X 60 X 1000 + 'U t When part of the air handled by the unit is taken from the room and the remainder from the outside, Adopted 1932. See A.S.H.V.E. Thansactions. VoL 38. 1932. of andAmerican Society Heating Ventilating Engineers Guide, 1936 Table 3. Typical Capacities of Unit Ventilators for an Entering Air Temperature of Zero Cubic Feet or Ajb per Minute 600. 750 1000 1200 1500 Total Capacttt in Square Feet or Equivalent Direct Heating Surface (Radiation) Capacitt Available for Heat ing the Room in Square Feet or Equivalent Direct Hbatino Surface (Radiation) Final Air Tempera* tube (Deo Faith) EDR Mbh EDR Mbh 285 350 455 565 705 68 84 110 136 169 95 115 150 190 235 23 28 36 46 56 105 105 105 105 105 Ht = 0.24Wo (V - to) 0.24 Wi y - t) (5) where W0 = weight of air, pounds per hour taken from out-of-doors. Wi -- weight of air, pounds per hour taken from the room. W0 = do 60 Qo where " ' Wi = di 60 Qi do = density of air, pounds per cubic foot at temperature Jo. di = density of air, pounds per cubic foot at temperature t. Qo = volume of air taken in from the outside, cubic feet per minute. Qi = volume of air taken in from the room, cubic feet per minute. <y = 0.24 H (Wo + Wi) +t Ht = H + 0.24 do 60 Qa (t - to) (6) (7) (8) (9) . Equations 5, 6, 7, 8, and 9 may be used in the same manner as is illustrated above for Equations 1, 2, 3, and 4. It may be noted in Equa tion 9, representing the total heat requirements,, that as the_ quantity Qo is diminished the heat requirements for the unit diminish very . materially. \ In Example 1, if the quantity of air taken in from the outside is reduced to zero, or all of the air handled by the Unit is recirculated, the total heat requirements Ht reduce from 99,600 Btu to 24,000 Btu, or to.about one' fourth. Such aunit handling one third of its air volume from the outside and two thirds from the room would show-a total heat requirement of 24,000 + 24,000 _ gg goo Btu. Units designed and operated o - ' on this principle show an average heat requirement and, therefore, a boiler capacity requirement of less than 50 per cent of that required for units taking all their air from the outside. , .. If all of the air is recirculated, the total heat required is the same as the heat loss of the room, or ' ` 234 Chapter 12--Unit Heaters, Ventilators, Coolers, and Air Conditioners Ht = H = 0.24 W (ty - J) (10) If the heat loss of the room is to be taken care of by the direct heating surface, the unit ventilators will be required to warm the air introduced for the ventilating requirements. Therefore: Hv = 0.24 W (ty - <o) (U) In this case ty should be equal to or slightly higher than t. If the unit ventilator were of such capacity as to exactly provide for the ventilating requirements, the direct radiation would be selected on the usual basis. However, it is necessary to employ a unit which may not exactly meet the ventilating requirements, since standard units are usually rated in terms of the volume of air that will be delivered at a certain temperature ty for an initial temperature of t0. Therefore a certain amount of heat (Hh) may be available from the unit ventilator for heating purposes, as pre viously stated, and the amount of equivalent direct heating surface may, if desired, be deducted from the amount required for heating the room. UNIT COOLERS Unit coolers as applied to industrial product conditioning and pro cessing are very similar in construction to unit heaters except that the heat transfer medium is supplied with refrigeration instead of with steam or hot water. They are normally installed within the space to be served, or at least closely adjacent thereto. Occasionally they are provided to receive outside air in which case this air is almost always filtered or washed to prevent any possible contamination of the product. Unit coolers are provided in two major types similar to unit heaters, either floor mounted with housed fan, or suspended with propeller type fans. Normally, air outlet velocities are lower than for heating, due largely to the effect of high velocities on the product. Consequently unit coolers are occasionally supplemented with duct distribution. Product cooling, originally was accomplished by means of stationary pipe coils. This was later supplemented with the forced fan bunker systems in which air was passed over banks of coils. The present trend in this field is toward a more accurate control of both temperature and humidity, thus placing these units in the classification of complete air conditioning units as discussed in the next section. However, in the majority of these cases dry-bulb temperature is controlled separately from the control of humidity, thus classifying these units as unit coolers. The principal field for unit coolers is in cold storage plants, fur storage, fruit packing houses, provision stores, brewery fermentation and stock. rooms, candy plants, and other industrial process, work. In replacing bunker and wall coils in meat-storage plants, unit coolers give distinct advantages in compactness, lower first'cost and maintenance expense, ease of defrosting, freedom from drip and the maintenance of sanitary . conditions, as well as uniform temperature and humidity under variable load conditions. Unit coolers by means of their positive air circulation prevent dead-air spots, frequently objectionable in this industry. Typical unit coolers are shown in Figs. 7 and 8. The former indicates a 235 of andAmerican Society Heating Ventilating Engineers Guide, 1936 suspended type unit cooler which may be designed with or without a moisture eliminator. If high air velocities are maintained, an eliminator will be necessary to prevent the drops of moisture from being carried through with the air.. The condensation that occurs is collected in a drip pan and removed from the system through a drain pipe. Fig. 8 indicates a typical floor-mounted unit of the housed fan type. The illustration shows a common form of distributing outlet designed to give low outlet velocities together with a controlled distribution. In process work, it is Chapter 12--Unit Heaters, Ventilators, Coolers, and Air Conditioners cooling unit. As soon as the ice and frost has been melted, the system is again returned to its normal cycle. 3. where brine is used as a refrigerant, heated brine may be sent through the cooler to remove the ice. 4. When the room is at very low temperatures, warm air defrosting is sometimes used by providing for the admission and removal of warm air from outside the cooled space. . 5. The surface may be sprayed with a strong brine solution. . In order to prevent the collection of frost in low temperature rooms where high latent heat loads are present, unit coolers equipped with a constant brine spray are frequently used. These are normally of the Unit Fig. 8. Floor Mounted Surface Type Cooling Unit with Distributing Outlets . often important that direct air distribution does not impinge on the product. Unit coolers are normally constructed of galvanized steel or non-/ ferrous material in order to reduce the corrosive effect of their constant wetted condition. .. . Unit coolers are often called upon to operate in rooms where a tempera ture below freezing is maintained and low refrigerant temperatures are required. This results in the collection of frost on the heat transfer surface which in turn leads to a rapid loss in capacity and requires eventual defrosting. Such defrosting is accomplished by the following methods: 1. When the room is above freezing the source of. refrigeration is cut off and the , fan allowed to operate until the unit has defrosted. 2. A reversal of the refrigeration system may be provided and the so-called hot gas defrosting method used. This is accomplished by reversing theiflow of the hot gas'so that it is delivered directly from the compressor to the evaporator of the 236 housed fan type similar to Fig. 9, but equipped With a pump for recircu lating brine over the coil. It is, of course, necessary to strengthen the brine at intervals to maintain a non-freezing mixture. . . Ratings of unit coolers may be expressed in Btu per hour, or in tons of refrigeration and should specify the quantity, temperature and humidity of the air entering the unit with a stipulated refrigerant temperature within the coil. When chilled water or brine is.used, the rate of circu lation of the cooling media as well as its entering temperature must be given. UNIT AIR CONDITIONERS According to the definition given in Chapter 44, to qualify , as an air conditioning unit such equipment must simultaneously control at least 237 of andAmerican Society Heating Ventilating Engineers Guide, 1936 the temperature, humidity, and motion of'the air within ;`the conditioned space. Air conditioning with unit equipment has gained in popularity during the last few years and some equipment offered does not fulfill the basic requirements of a true air conditioning unit. It is to be noted that air conditioning'equipment must1 have the ability not alone to alter the temperature or humidity within the conditioned space, but it must. control these conditions. Thus, some equipment that attempts to provide cooling or humidification does not have the capacity or means of actually controlling these conditions. .... . In selecting and specifying Jhq unit types, the results desired should be carefully, determined. If, the simultaneous control of temperature, humidity, air motion, and distribution within the enclosure is not required then the simpler and less expensive unit heaters and unit coolers may be considered. Complete' air conditioning should simultaneously control the following featured: ""' 1. Air temperature. 2. Air humidity (moisture content). 3. Air motion and distribution. . 4. Air purity. . . , ")' , t m' * Three general classifications of unit air conditioners are recognized: . 1. All-year conditioning involving the control of these conditions both in summer and winter and thus requiring both heating and cooling as well as humidifying and dehumidifying. v 2. Winter conditioning in which heating and humidifying alone are controlled . together with air motion and air purity. . 3. Summer conditioning involving cooling and dehumidifying with air distribution and cleaning. The means of accomplishing tlrese functions are outlined herewith:' Heating J The normal air conditioning unit derives its heating function.from, a heating coil, usually of the nbn-ferrous finned tube type supplied with either- steam or hot water. Steam" may be supplied directly from a self- contained and built-in oil or gas" fired unit, from a separate domestic steam boiler, or even from an outside source of a-central heating plant. Hot water is supplied either from a separate hot water boiler or in rare instances from a domestic water heateV. ' In domestic or household conditioning units, adapted from a warm-air heater to which humidification is added, or possibly all-year-round con ditioning, a direct-fired air interchanged is frequently used.. The source of heat in this case may be from the combustion.of coal, oil, or gas; A wide variety of designs and structures are used?' In such direct-fired systems, the bulk and volume of the heat transfer surface is necessarily large in proportion to the rest of the equipment. 1 Where electric power is low in cost, electric heat has been furnished in unit air conditioners either in the .form of encased heaters, or open wire heaters. (See Chapter 39.) Radiant electric heaters are seldom used except as their radiant heat is absorbed by some receiving walTand there transmitted to the air in the. form, of convected heat. 238 j Chapter 12- Unit Heaters, Ventilators, Coolers, and Air Conditioners Another method of applying electric heat is by means of the reversed refrigeration cycle, whereby electric energy is used to compress a re frigerant and to deliver the heat of compression, withdrawn from a lower temperature source, to the conditioned space by locating the condensing coils in the air circulation circuit of . the unit conditioner. While this method of heating has gained wide interest, it is practical only in a limited number of applications. Its economic practicability depends largely upon the availability of a source of heat during the winter season at as high a temperature as is possible. Thus, while it is frequently applicable in mild climates, it is not of great value in the northern climates where sub-freezing temperatures are common. It has the other unfor tunate property that when the outdoor temperature is the lowest and the heat requirement the greatest, the heating capacity of the system is a minimum. This means that in many installations, an auxiliary and separate source of heat must be supplied to carry through these peak winter conditions. Such factors as these have limited a more general application of this principle. (See Chapter 2 on Refrigeration.) Humidifying - A very wide variety of humidifying means havt been used to furnish humidification in winter to air conditioning units. The oldest and best known is by means of a direct spray which is used in many different ways. The simplest system is where the spray water is furnished from a constant water source, such as city water, and is permitted to run to waste. Under such conditions, the spray may be either of the 'direct atomizing type where, by means of the nozzles, the water is broken into fine particles or of the so-called target spray type, Where a fine stream of water under pressure is caused to impinge uppn a flat surface or target. Such methods are normally rather inefficient in the use of water.- . -. Any.spray, system where water is.run to waste m,ust of necessity atomize as completely.as possible.to provide for evaporation.of the.maximum amount of water. / This normally..calls 'foe moderately, high pressures and for very'fine orifices or passages ^ order to- produce fine atomization. This in turn involves the danger of occasional clogging of. the nozzles .with resulting service problems. Recently'a,dumber of self-cleaning nozzles have come on to the market which giv^^romise of reducing this hazard. Such methods- even 'at*best'.are wasteful of water inasmuch as bnly a comparatively small piro^ortidn of the water used is actually evaporated, the remainder trun,nirtg tip waste. In'spite of the water .wastage' this method is" honhally more economical in the case of'small'conditioning units than the installation of a pump'to recirculate and reuse the waste water. - - ::: 1 ' . In the larger conditioning, units`where)much larger quantities of water - are used and the amount of water..wastage becomes an appreciable item, it frequently is profitable to install a'recirculating .pump. Comparatively few units employ this recirculating system. It is'important to note that when spray water is recirculated in such equipment in industrial areas and in large cities, it becomes necessary that Water treatment be supplied, in order to reduce the corrosive action' resulting from the absorption of acids and impurities from tHe air: . . - : " :. . - y 239 of andAmerican Society Heating Ventilating Engineers Guide, 1936 In some units, in order to increase the humidifying capacity, and to utilize a greater portion of the spray water, the atomized spray is per mitted to impinge against a heated surface thereby forcing its evapora tion. While this is practical in some instances, there is danger of scale formation where hard water is employed. It should be pointed out that in any atomizing system if extremely hard water is used, the air will carry with it a- content of infinitely fine solids which should be removed by a filter before discharging into the conditioned space. If it is not so re moved, this may result in the formation of an apparent dust upon furni ture and exposed surfaces. One of the simplest methods of humidification in winter is by means of a direct steam spray. This is seldom used in unit conditioners for comfort applications due to the resulting odors. In industrial applications, how ever, it finds frequent use. The steam is usually introduced to the air through a perforated tube or through some type of porous material. . If a small atomizing spray is not used in comfort conditioning units, the evaporative pan type of humidifier is usually employed. This consists of a container offering as much water surface as possible and equipped with means of heating the water. This heat may be applied either electrically, by steam, hot water, or by circulation of the water from a heated space through the evaporating pan. Since the humidification is accomplished by surface evaporation only, it is essential that the air stream be directed across the surface and that the evaporating surface be large. While this system eliminates the dusting hazard when hard water is used, with a spray system, hard water tends to scale the heating surface and results in loss of capacity and the need for frequent cleaning. The rate of evaporation per unit surface exposed is low. Thus it frequently becomes difficult to provide sufficient surface for adequate capacity. The higher the temperature of the water, the lower the relative humidity of the air; the greater the velocity over the surface, the greater is the ratecf humidification. The evaporative pan type of humidification limits the water wastage and is usually supplied with water through a float valve. Due to the collection of salts in this evaporating pan such humidifying systems require occasional drainage and cleaning. Other methods of humidification attempted in air conditioning units are through the use of wetted fabrics, porous earthenware plates, or other, capillary surfaces. These methods rely upon the capillary absorption of the moisture up from the liquid level into the portion exposed to the air. They have a tendency to lose their effectiveness due to the resulting deposit of mineral salts at the evaporating surfaces thereby clogging the pores and reducing the contact of the air with the water. Also they frequently become foul and often support bacterial growth. The capacities of any of the above methods of humidification are affected by the temperature and relative humidity of the air passing through the humidifier. The higher the temperature, the lower the relative humidity, the greater will be the rate of humidification. Cooling and Dehumidification _ Those units that employ recirculated water sprays will undoubtedly use such sprays as their means of cooling and dehumidification by 240 Chapter 12- Unit Heaters, Ventilators, Coolers, and Air Conditioners . furnishing refrigeration to the water in circulation. Occasionally where an adequate.source of cold well water is available, this may be used as a direct spray and run to waste. , Other methods of dehumidification accomplished by direct contact with the transfer medium are by means of the so-called adsorption and absorption systems. (See Chapter 2 on Refrigeration.) It must be recognized that these methods of dehumidification.do not in themselves provide cooling. The substance removes the water vapor from the air thereby heating it. This highly dehumidified air may then be cooled either by partial rehumidification or by direct contact with a cooling medium of cold water or direct expansion refrigerant. There are now on the market solid adsorbents such as silica gel, and activated alumina, and liquid adsorbents such as calcium chloride in solution and lithium chloride which is one of the most promising examples. Finally the most common direct means of cooling and dehumidification is through the use of ice. In such units the ice is brought into as intimate contact as possible with the air handled. Provision is made for ithe removal of the moisture as rapidly as it is formed from the melting of the ice. One method employed is to mount the ice on metal grids and then draw the air over the cold grids as well as over the projecting pieces of ice formed between the grids. Of course, ice is also used to cool water which is circulated through the sprays; In conditioning units, the use of surface cooling is probably more common than direct spray or other direct transfer means. The type of surface employed may, of course, be cast or fabricated from tubes. In present-day practice finned tubes or plate fins through which tubes are passed form the most generally used cooling surface. The detailed fabri cation of this surface and the arrangement of the tubes will depend largely upon the type of refrigerant for which it is intended. The simplest construction is where chilled water or brine is used as the refrigerating medium. With direct expansion refrigerant it is usually necessary to provide a special arrangement of headers so that proper distribution of refrigerant through all the surface is obtained. In some cases, ordinary brine coils can be used when operated as a flooded refri gerant system. ' In some units a combination of a direct spray and a refrigerant surface is used, the spray being directed against the surface. Such systems claim the advantage of air washing together with the maintenance of a clean and effective cooling coil. . - it snouia oe noted that when surface coolers are used, adequate pro tection in the form of filters or at least lint screens are necessary to prevent fouling of the surface from the air borne dirt. Surface not so protected frequently becomes completely matted with lint, grease,, and similar dirt. The sources of refrigeration used with these surface type conditionii^^ units are discussed in Chapter % on Refrigeration. However, they may be divided into the following groups: ____ cApausiuu icuigerant. in wnicn tne nquiu icuigciaui cyapuraxeu within the coils of the unit. The vapor from these coils may be recompressed in centrifugal; rotary, or reciprocating type compressors, and the refrigerant again returned to the evaporator coil. . -. of andAmerican Society Heating Ventilating Engineers Guide, 1936 2. Indirect refrigeration by means of: a. Cold well water. b. Cold city water. . c. Artificial refrigerated water provided by direct expansion of refrigerant in a water cooler, direct steam jet refrigeration, or by the melting of ice. . ; It should be recognized that direct expansion of refrigerant within the coils of a unit conditioner, represents a certain hazard unless the refri- gerant is of the non-irritating; non-inflammable type. Therefore, in many cities rather stringent codes have been set up limiting the use of such direct expansion unit conditioners. In the case of hospitals, or places where a large number of people are present, direct expansion is prohibited and the so-called indirect systems are required. In these systems the refrigerant is used to cool a brine which is then circulated through the cooling coil. - 1 i ' : ' Filtering--Air Cleaning . A variety of methods are employed as a means of controlling air purity. In unit systems where filtering alone is considered satisfactory, the degree of filtering varies widely and in proportion to the actual needs. If the air is chiefly recirculated with but little outside air used for ventilation, > filtering requirements are largely limited to keeping the coils in a clean and operable condition. Thus such units are frequently furnished with simple lint screens of low resistance and formed of moderately close meshed wire. Where.outside air is used for ventilation, more complete- * filtering of dust particles is necessary and for this purpose, there are/'a . large number of filters available on the market. Some of these filters are : of the so-called throw-away type, constructed of inexpensive material so that when they become dirty or clogged they may be thrown away and ; replaced with new ones. All of these filtering methods are described in detail in Chapter 16. J A number of air conditioning units are being offered for the relief of hay fever sufferers and render relief in this disease both by maintaining proper -1 air conditions and by removing most of the air borne pollens from the ventilated air. Such filters, however, must be designed for this purpose k and must have an exceptionally high efficiency. The degree of filtration and its efficiency depends entirely upon the design of the unit or the unitary system. For high efficiency of air cleaning, large and expensive filtering arfea is required. Small filters mean either low efficiency of cleaning or else high resistance with increased fan power or decreased air capacity. .. Ventilation . . :i '\ Inasmuch as air pqrity is one of the factors that constitutes true air conditioning, ventilation pr the introduction of outside air is an essential part of-any air conditioning unit or system.: While a unit that recirculates all its air capacity is still considered an air conditioning unit, the better type system provides for the introduction of a certain proportion of out-door air. In some instances one of several units may operate entirely on outside air, while in other cases only a portion of the air handled by the unit is drawn from out of doors. In such cases a damper is provided either i | | fe | \ i | Chapter 12--Unit Heaters, Ventilators, Coolers, and Air Conditioners in the unit or in the duct connections for controlling the proportion of out-door air. Location of Unit Conditioners . The characteristics of the conditioned space, the building construction, ' the type of system employed, and the source of duct connections, power, piping, and refrigeration influence directly the location of the unit con ditioners. Primarily a unit conditioner is either of the portable or fixed type. The portable unit is usually a simple summer conditioner either with or without ventilation, but includes the refrigerating compressor. If this compressor is of the air-cooled type, the unit must be located adjacent to a window or other source of outside air. On the other hand, if it is of the water cooled type, its location should be made convenient to sources of water and drainage. Thus portable units are almost invariably located within the conditioned space. Non-portable units, or units of fixed location may or may not be located within the occupied space. Naturally units that are located in such spaces must be built with decorative cases in order to harmonize with the surroundings. Such units are normally of comparatively small capacity varying from a fraction of a ton up to as much as five or six tons. Many conditioning units and particularly those of the larger sizes are located externally to the occupied and conditioned space and are connected thereto by means of delivery and return ducts. Such an arrangement permits the location of the conditioning unit convenient to either the sources of refrigeration or outside air. It frequently permits the use of the basement or of space less valuable than that on the level or floor of the occupied zone. Oftentimes the same type of unit may find application in an exposed position for one job and in a concealed location for another. Thus it can be seen that it is not possible to define a unit merely on the basis of its location. Frequently conditioning units are built into the structure or into the architectural design of a room so that they are entirely concealed except for the discharge and return grilles or openings which are designed so as to correspond to the decorative scheme of the room. Air Distribution ` ' With portable units or units exposed within the conditioned space, the distribution is usually through grilles or louvres built entirely into the equipment. The discharge of the air from this unit, in general, should be upward immediately at the conditioner, with sufficient horizontal com ponent to carry it to the most remote point in the room. Such a distribu. tion permits the cool air to drop slowly over the entire zone and return to the inlet of the unit below the breathing line and along the floor. The location of doorways, air vents, and heat exposed walls should be carefully observed, as they have a marked effect on the direction of the air flow and u ' ell "niformity temperature. Velocities below the breathing line should be kept low, normally not over 40 to 7ff fpm. Such velocities are usually best checked by a Kata thermometer rather than, by means oi an anemometer. With the suspended type of unit conditioners located within the con^ uitioned space, sufficient outlet air velocity should be provided to givA 243 v of andAmerican Society Heating Ventilating Engineers Guide, 1936 adequate induction and mixing with the room air thereby preventing the immediate dropping of the air stream and resulting objectionable cold drafts. This is one of the limitations to the size of such suspended units inasmuch as it is difficult to distribute from one point a large refrigeration tonnage without cold drafts. Where the units are located without the conditioned space, air dis tribution is more frequently provided through multiple outlets located in ducts from the conditioning unit. The location of these outlets is quite critical and is influenced both by the building construction, economies of connections and by the distribution of load. Normally with a cooling system, it is desirable to blow the conditioned air toward the exposed walls or windows. This delivers the cool air to the point where it is most needed. These problems are discussed in considerable detail in Chapter 19. Chapter 12--Unit Heaters, Ventilators, Coolers, and Air Conditioners a remotely located compressor. A cooling coil for use with chilled water can be substituted for the direct expansion coil indicated. The fans below the separate cooling and heating elements deliver the air against deflectors thereby obtaining distribution across the face of the element and pre venting condensate from dripping down into the fans. The plate upon which the fans are mounted serves as the drip pan from which the water is conducted to the drain. Separate elements are used for heating and for cooling. Thus this unit may be used automatically for heating and cooling without manual control. When the unit is used for summer conditioning only, the heating coil may be omitted for the installation. The illustration indicates an evaporative type humidifier and drain pan. Fig. 10. Floor Type Unit Conditioner for Heating and Cooling There are a wide variety of outlet types used. Most of these have fixed delivery characteristics, thus requiring careful consideration in their location. Some types of outlets are now available with adjustable vanes thereby permitting some alteration in the delivery of the air stream after installation. This frequently eliminates objectionable down drafts resulting from the impingement of the air stream against posts, pillars, lighting fixtures,-and beams. Construction of Apparatus ' The types and. designs of air conditioning units in production and pro posed are legion. New designs are constantly appearing, with new improvements, greater capacities, wider range of application and superior construction. .It will be impossible to cover in this chapter the many types of construction on the market. Illustrations of current makes and - models will be. found in the Catalog Data Section. A few typical designs of conditioning units will be described in detail. Fig. 10 shows an all-year floor type conditioning unit for exposed location and with direct expansion coil supplied with refrigerant from 244 Fig. 11. Conditioning Unit with Top Inlet and Outlet Other units are on the market in which a target spray humidifier is substituted for the evaporative type thereby providing a unit for summer cooling and dehumidification, at the same time supplying humidification in winter for application in rooms with other existing heat sources. Still another unit is available in which the fans are mounted at the top of the unit delivering directly through a grille and drawing their air supply through the cooling and heating coils. Other variations in pro portion and details of construction of this general arrangement are common. With this type of unit conditioner, ventilation is usually provided by means of a separate duct connected to the inlet of the unit. An entirely different arrangement shown in Fig. 11, places both the air inlet and the discharge at the top of the unit. The fan at one side dis charges the air downward to the bottom where it turns and passes hori zontally through an atomizing spray air washer. The path then con tinues upward through eliminators, a cooling surface and a heating surface before it leaves the unit. With steam or hot water connected to the heating element, tempered water to the sprays and refrigerated water A 245 ^ American Society of Heating and Ventilating Engineers Guide, 1936 the cooling element, this unit gives controlled temperature, humidity, air cleaning, and air movement in both summer and winter. Air washing may be connected in summer, or in intermediate season to remove room odors. Excess water is run to waste. Acoustical treatment of the housing and outlet baffles permits installation where noise requirements are exacting. . ' One of the recently developed units, designed particularly for low cost installation is shown in Fig. 12. Twin fans with wheels mounted on extensions of the motor shaft take the air from the floor, send it downward 12-Chapter -Unit Heaters, Ventilators, Coolers, and Air Conditioners Fig. 12. Simple Spray and Coil Unit Conditioner through a passage containing a water spray and then upward through a double set of coils for cooling and heating, the air leaving the cabinet through a top grille. The spray nozzles'-are supplied with city water, the excess collecting in the air reversal chamber and running to the' drain. The cooling coil uses water either from city6 mains or from other low temperature sources, or a special direct expansion' coil may be provided. This unit like others may be equipped with automatic controls. Fig. 13 illustrates a common type of suspended type unit conditioner for exposed location utilizing a' propeller type fan and suitable for summer conditioning only. Such units are equipped with either a direct expansion coil or one for chilled water of brine circulation. The outer cabinet is commonly of wood-grained steel or baked enamel and is insulated from the cool air chamber to prevent external condensation. The drip from the coil is collected in an insulated drip pan and carried to a drain. The inlet to the unit is provided with a lint screen to protect the. cooling 246 Fig. 13. Suspended Propeller Fan Type Unit Conditioner surface. Such units are normally used for recirculation only but may be connected for ventilation through short full-size ducts. Similar units are available with twin housed fans of the same general construction, although usually such fans draw the air instead of blow it through the coils. A self-contained completely portable unit conditioner is illustrated in Fig. 14. For the operation of this unit, it is only necessary that it be located adjacent to a window or shaft to which air connections can be made and to plug in the motors to a convenient light socket. In this unit, the conditioned air enters on the side, passing through a grille, filter; and cooling coil and is delivered vertically to the room through a special motor and fan assembly. Refrigeration is furnished by a reciprocating compressor driven from a motor located in the base. This compressor utilizes ah air cooled condenser. Air is drawn into the base by a fan mounted on the compressor motor, so arranged that the air passes through the refrigeration condenser and is again discharged out through the window connection. A novel feature of this design is that the condensate Fm. 14. Portable Self-Contained Air Cooled Conditioning Unit 247 of andAmerican Society Heating Ventilating Engineers Guide, 1936 AIR Chapter-12--Unit Heaters, Ventilators, Coolers, and Air Conditioners line surge and reducing light flicker. These water cooled units either eliminate or reduce the need for out-door air connections. Due to the. necessity of water and drain connections they are not as portable as the air cooled type. Remotely located conditioning units vary widely in details of con ' struction. Fig. 15 and 16 indicate one type built in sections thereby permitting interchangeability of application with a minimum change in parts. The vertical unit shown in Fig. 15 consists of a fan section, housing one or more fans, mounted on a coil section in which are located a heating coil and a cooling coil, which may be built for either direct expansion refrigerant, chilled water, or brine. These two sections are supported on a third or drip-pan section. The distributing duct system is attached to the fan outlets and returned fresh air connections are made to the drip pan. A filter box is illustrated attached to the drip pan section. By Fig. 15. Vertical Remote Type All-Year-Round Conditioning Unit from the cooling coil is sprayed over the condenser surface and there vaporized, thus eliminating the-need for drain connections. One advan tage of this type of conditioning unit is that it may be removed frorn.-the occupied space during the winter season when cooling is not needed. Another type of portable unit for occupied space locations differs from the former in that the compressor is water cooled and a connection to water and drain must be provided in addition to the electric connection. Water and drain lines are carried in a composite hose, especially built for this purpose and connections are usually, made to a nearby washbowl. In order to reduce the starting load, one model has two separate motors brought on to the line at delayed intervals thereby decreasing the initial Fig. 16. Horizontal Remote Type All-Year-Round Conditioning Unit 248 . Fig. 17. Residential Conditioning Unit with Hot Water Boiler eliminating the vertical type- drip pan and substituting a horizontal drip pan, this unit is converted into a horizontal suspended type conditioning unit for connection to duct work, both with and without filters. The previous figures have largely confined themselves to the illustration of all-year-round or summer conditioning units for office or commercial application. The smaller conditioners have, of course, been applicable to residences. There remains a field of unit conditioners primarily adaptable to residence work. They are in general the outgrowth or adaptation of mechanical warm air systems to conditioning, which are covered in Chapter 23. However, the following illustrations will cover details not included in that chapter. . . , Fig. 17 illustrates'a conditioning unit attached to a hot water or steam boiler and as showmmay furnish winter conditioning or, by connecting a cooling coil to a source of refrigeration, will supply year-round con ditioning. Such a system lends itself particularly to the so-called split system from which a portion of the residence may be conditioned summer and winter, while the garage or servants' quarters will have only heating in winter,1 the heat being furnished directly from the-boiler and not through the conditioning unit. ' ....... /. Fig. 18 shows a gas fired furnace unit equipped with an air washer, and represents a winter conditioning unit furnishing filtering, heating,; and 249 American Society of Heating and Ventilating Engineers Guide, 1936 humidification. If the air washer is supplied with refrigerated water, this unit would become a year-round conditioner. - ' For fuel oil the equipment shown in Fig. 19 can' be installed to obtain warm, filtered, and humidified air. An oil burner and heat exchanger provide the heat. A cooling section may be inserted between the fan and the heat interchanger, cold water, or refrigerant being circulated through the cooling element. For thermostatic control, a room thermostat is provided to start the oil burner when the temperature falls, the rising temperature in the heat interchanger causes the thermostat to start the fan. As soon as the temperature in the house rises to normal, the room thermostat shuts down the dil burner and operates the thermostat con trolling the fans. BASIS OF RATING In the past, the unit air conditioning industry has been handicapped by the lack of any standard method of rating. Recently a tentative code has been prepared defining a complete rating method6. Supptu Air to fcoms Chapter 12- Unit Heaters, Ventilators, Coolers, and Air Conditioners relative humidity entering air. conditions. The Catalog Data Section gives ratings of current models offered by leading manufacturers. METHODS OF CALCULATING CAPACITIES The methods of calculating heating and cooling loads for conditioning units are similar to those described under Chapters 7 and 8. Certain manufacturers have adopted simplified and approximate methods which through experience they have found applicable to unitary equipment. Such methods involve certain averaging approximations which are suitable for estimating purposes but many of which require rechecking on a more accurate basis before actual installations are made. The greatest error in calculating cooling loads is apt to be introduced in the failure to appreciate the magnitude of the latent heat loads and the On the basis of this new code, air conditioners are to be classified primarily as free delivery type and pressure type, where delivery will be measured in cfm standard air at specified fan speed. Pressure type units will specify the delivery against various total fan static pressures. Cooling capacity will be expressed in total Btu per hour and this total will be Sub divided into sensible heat cooling effect and dehumidification or latent heat effect. Cooling capacities will be given on entering air temperatures of 85, F, 50 per cent relative humidity with 40 F refrigerant temperature for comfort conditions and 45 F, 85 per cent relative humidity with 30 F refrigerant temperature for commercial applications. . The duty for heating surfaces will be specified in Btu per hour for 70 F entering air temperature based on two pounds gage steam pressure or 180 F entering water temperature with 20 F drop. Humidification will.be specified in pounds of water evaporated per hour at 70 F and 30 per cent Code prepared by Joint Committee of American Society of Refrigerating Engineers, American Society" of Heating and Ventilating Engineers, Refrigerating Machinery - Association, National Electric Manufacturers Association and Air Conditioning Manufacturers Association. ` 250 --. relationship between the latent heat removal and the refrigerant tem perature. It is extremely important that the proper balance be obtained between the refrigerant temperature, the conditioning unit surface and the conditions to be maintained within the occupied space. Unsatisfactory conditions often result through the attempt to apply unit conditioners with a source of refrigeration which gives too high a surface temperature. Such conditions may be obtained when well water of too high a tem perature is used or when a direct expansion evaporator is connected to a refrigeration compressor of inadequate size. The high refrigerant tem perature even though it may give adequate dry-bulb temperatures, due to over-size conditioning units, will not give proper humidity control due to its inability to furnish sufficient dehumidification. The use of surface coolers with widely extended fins may lead to similar results since the large ratio of extended surfaces gives an average surface ' temperature considerably above the refrigerant temperature within the tubes. All these factors must be kept in mind when making the selection of equipment. It is furthermore vital that the calculation of a cooling load be based on an accurate survey before the selection of the equipment is made. . 251 American Society of Heating and Ventilating Engineers Guide, 1936 COSTS Due to the rapid development of the air conditioning industry and the great progress that is being made each year, it is impossible to give any cost figures that will be of value. There are, however, certain factors that influence the cost of unit air conditioner installations. 1. Since the cost of the total job involves material cost plus installation labor and since through the use of unitary equipment, material costs can be kept to a minimum, every effort should be made to simplify installation. ' > 2. Self-contained units in the small sizes now available, probably represent the lowest cost individual installations. They have, however, their limitations. 3. The floor type all-year-round unit conditioners for the occupied space with a remotely controlled compressor, heating sources being either the existing heat system or steam connections to the unit, probably afford the lowest cost all-year-round service for most individual rooms. This is particularly true in the case of residences. With offices, this will probably be true if the compressor can be located immediately adjacent to the conditioned space, as for example in a closet or nearby store room. The expenses increase rapidly as the distance from the unit increases. 4. For multiple rooms or offices, the remotely located conditioner with connecting ducts probably represents the most economical installation. Such installations are also particularly adaptable to stores, residences and small commercial installations. Costs of operation vary widely depending entirely upon the cost of power and water. Water costs in the larger installations are being materially reduced through the use of cooling towers and special types of condensers. The normal expense of operating the cooling system is considerably in excess of that of winter heating both as to the first cost and as to operation. Consequently, the more rapid growth of air con ditioning has been along commercial lines where it has represented an actual profitable investment resulting in increased business returns rather; than along the lines of residential comfort cooling where it still represents a luxury in comfort. . MISCELLANEOUS UNITARY EQUIPMENT There are a number of units available which were not covered in tlie previous discussion that accomplish only one or two of the functions of air conditioning. Attic Fans ' .''' Attic fans, used during the warm months of the year to draw large volumes of outside air through a house, offer a means of using the com-, parative coolness of outside evening and night air to bring down the inside temperature of a house. ` Because the low static pressures involved are usually less than }/% in. of water, disc or propeller fans are generally used instead of the blower or housed types. The fans should have quiet operating characteristics, and they should be capable of giving about thirty air changes per hour. The two general types of attic fan installations in common use are: . Open attic fans, in which the fan is installed in a gable 'or dormer and " one or more grilles are provided in the ceilings of the rooms below. 252 ^Chapter 12--Unit Heaters, Ventilators, Coolers, and Air Conditioners Fresh air, which enters the house through open windows, is drawn into the attic through the grilles, and is discharged out-of-doors by the fan. An attic stairway may be used in place of the central grille. It is essential that the roof and the attic walls be free from air leaks. Boxed-in-fans, in which the fan is installed within the attic in a box or housing directly over a central ceiling grille, or in a bulkhead enclosing an attic stair. The fan may be connected by a duct system to the grilles in individual rooms. Fresh air entering through the windows of the rooms below is discharged into the attic space and escapes to the outside through louvers, dormer windows, or screened openings under the eaves. The locations of the fan, the outlet openings, and the grilles should be chosen after consideration of the room and attic arrangement in order to give uniform air distribution in the individual rooms served. If the outlet for the air is not on the side away from the direction of the prevailing wind, openings should be provided on all sides. Kitchens should be separately ventilated because of the fire hazard, and to prevent the spread of cooking odors. The operating routine which will secure best results with an attic fan is an important consideration. A typical routine might require that in the late afternoon when the outdoor temperature begins to fall, the windows on the first floor and the grilles in the ceiling or the attic floor should be opened, and the second story windows should be kept closed. This will place the principal cooling effect in the living rooms. Shortly before bedtime, the first floor windows may be closed and those on the second floor opened, to transfer the cooling effect to the sleeping rooms. A time clock may shut off the fan before waking time, or the fan may be stopped manually at a later hour. A disadvantage arising from the passing of a great amount of outside air through a house is the dust nuisance, which varies considerably in different locations. Persons suffering from allergic diseases caused by air borne pollens will have their troubles increased with attic type coolers. Some typical data on an attic fan installation in an average six-room house of frame construction containing 14,000 cu ft and located in the southern part of this country are: Installation cost......... Fan data....................... Operating period........ Power consumption.- $75 to $400, average $250 9000 cfm average, 280 rpm if belt driven, 570 rpm if direct connected, 500 watts input April 15 to October 15, intermittently as weather con ditions demand 500 kwh per year for 8 months' operation Humidifiers . Humidifying units may be installed as part of an air conditioning unit system, or may be installed individually to furnish additional humidity. Fig. 20 illustrates a humidifying unit for installation in connection with a warm air heating system, and as such it is located at the intake of the 253 1 American Society of Heating and Ventilating Engineers Guide, 1936 furnace. The air passes through a lint filter, then through the fans and finally through an air washer or spray system. Surplus spray is eliminated and the air delivered to the hot air system. In other cases, similar spray type apparatus is used to deliver humidified air through ducts to openings beneath existing radiators in a steam heated house. For other steam heated homes, there is a humidifying unit as illustrated in Fig. 21. This unit is normally placed at some central location on the first floor, and receives the air from the floor into fans, delivering it through a heating coil and up through a target spray atomizer. Surplus Fig. 20. Humidifying Unit for Warm Air Furnace moisture is removed by means of an eliminator filter and the humidified air is delivered upward through the other half of the floor grille. Since a large percentage of the heater capacity is transformed into the latent heat of humidification, this unit does not eliminate any existing steam, radiation. It may also be used with hot water systems but its capacity is considerably reduced. N ' CONTROLS ` The controls of all unitary equipment represent a vital part of their successful operation. This is particularly true in the case of conditioning equipment where a very close inter-relationship exists between the thermostatic room controls and the refrigerating unit controls. . The proper selection of controls and the proper adjustments extremely important to prevent short cycling of compressors. Furthermore, the , proper adjustment of direct expansion valve controls is likewise extremely important. .. A detailed discussion of control problems is contained in Chapter 14. 254 '- ' . Chapter 12--Unit Heaters, Ventilators, Coolers, and Air Conditioners PROBLEMS IN PRACTICE 1 Distinguish between a unit and a central, type of air conditioning system. In a unit system, the air treating apparatus consists of factory assembled equipment which is shipped substantially complete or in sections and is installed without field fabrication except for the duct connections between the equipment and the point of delivery of the air. Usually the air treating equipment is located closely adjacent to the conditioned space and serves a limited area, A central type of air conditioning system localizes the air treating equipment for the entire area at one point and involves the field assembly of a large number of individual elements. Manufacturer of the unit is responsible for the out-put and performance of the unit under rated conditions, whereas, the contractor installing the completely unitary or central type equipment is held re sponsible for the complete performance of the system. 2 Is it satisfactory to use superheated steam in unit heaters? Superheated steam can be satisfactorily used in unit heaters provided the capacity is based on the saturated steam temperature and not on the total temperature. If un usually high superheat is used, trouble may be experienced from the excessive expansion and contraction of the heating elements. 3 Is it satisfactory to install one unit heater as the total load on a coal fired boiler? ' ' . .. Such an arrangement is impractical if the unit heater is started and stopped in keeping with the room temperature. However, if the room temperature controls the steam pres sure and the unit heater is arranged to start when there is steam in the mains and to stop when there is no steam in the mains, such an installation will be satisfactory. 4 Will a unit heater with a slow speed fan be more quiet than one with a high speed fan? . The speed of the fan is no indication of quietness. Quietness is a function of the type, diameter, blade form, speed, and location of the fan! 5 Is it satisfactory to use steam at pressures less than atmospheric for unit heaters or unit ventilators? ' If the air inlet temperature is above freezing, steam at any pressure may be used in the heating element of the unit heater or unit ventilator. If the inlet temperature is below freezing the heating element should be filled with steam of at least 5 lb pressure (or with a positive 5 lb pressure differential between supply and return) and the steam supply should never be throttled or the heating element may be frozen. 6 In general, what is- the primary function of a unit ventilator? To maintain the desired room air conditions as to temperature, air change, and air cleanliness, without drafts regardless of variations in outdoor temperature, occupancy, sun heat, and wind. . 7 What are the usual working parts of a unit ventilator? The fan and motor assembly, a set of heating elements, outdoor and indoor air dampers, filters (optional), outlet grille, some method of varying the outlet temperature in keeping with the room requirements, and, in the case of some unit ventilators, a method of limiting the.outlet temperature to a minimum of 60 F. , . 8 9 Do all unit ventilators introduce a constant amount of outdoor air? 1' Certain types employ full recirculation except when outdoor air is obtained by throttling the steam valve on the heating element so the proportion of outdoor air to room air is . varied. This is a very economical type of unit ventilator but in some communities it cannot be used because of existing laws which require that some fixed amount of outdoor air be introduced whenever the room is occupied. Certain types of units are designed to always take in a minimum quantity of air from the outside and to automatically vary this with the weather. 255 American Society of Heating and Ventilating Engineers Guide, 1936 9 V Why are metal surface cooling elements instead of liquid spray chambers used in the design of most unit air conditioners and unit coolers? The first cost of the surface cooling type of unit is considerably less than the cost of spray type equipment. Further, the requirements of many industrial air conditioning jobs and of all comfort cooling jobs where unit equipment is applicable can often be effectively met with the use of surface type units, with a reduction in the space required for making the installation. Where space conditions are especially limited, the cross sectional area of the surface cooler can be reduced because the resulting increase in velocity over the coil surface increases the effectiveness of the surface, whereas an increase in velocity through a liquid spray would reduce its effectiveness.- 10 Why are air conditioning units with metal cooling surfaces not desirable for all industrial jobs? Wherever unusually close control of relative humidity is required, a spray type unit will prove to be more satisfactory. Relative humidity control and accurate temperature control, however, can be maintained without difficulty with the use of metal surface units. . 11.# Why is accurate control of relative humidity with surface coolers more or less complicated? A surface cooler cannot add moisture to the air, and moisture is removed only when the surface temperature is below the entering dew-point temperature. Any change in condition of the entering air will result in a change in the dry-bulb depression of the leaving air. This change in entering condition requires not only a readjustment of the air volume but also a change in the coil temperature, if accurate control over the relative humidity is to be maintained. 12 # What in general are the characteristics of unit conditioner operation using surface coils? For a constant entering dry-bulb temperature and a constant refrigerant temperature any increase_in the entering wet-bulb temperature will produce a rise in the leaving drybulb temperature with an accompanying reduction in the wet-bulb depression of the leaving air. The sensible heat removed by the unit decreases and the latent heat in creases, while the total heat removed also increases. When the dry-bulb temperature of entering air is increased, with constant refrigerant temperature and constant wet-bulb temperature of entering air, the wet-bulb depression of the leaving air increases, and since it is this depression which determines the maintained relative humidity it must be carefully considered when selecting the unit.13 13 If a drop in the dry-bulb temperature of entering air reduces the capacity of the unit, is there hot danger of selecting a unit which is too small, if its selection should be based on an excessive entering dry-bulb temperature? Yes. If the total cooling, load is largely internal (such as from occupants and lights) as distinguished from the cooling load of outdoor air, and the unit is selected on the basis of a too high dry-bulb temperature of entering air, then, in the event of.under capacity, it might be possible to maintain the room temperature by reducing the quantity of out door air. But this increases the recirculated air taken, into the unit, reducing the dry- bulb temperature of entering air and, therefore, reducing the sensible heat capacity of the unit. This reduction in capacity may offset the gain obtained by reducing the amount of outdoor air taken.in. Further, since-the total tonnage required for any instal lation is equal to the total internal heat load plus the total heat removed from the out door air, and since the outdoor air might have a wet-bulb, temperature equal to the designed wet-bulb but less than the designed dry-bulb temperature," then the sensible heat capacity of the unit will-be. less than that required. It follows that unit air con ditioners and coolers should not be selected on a basis of the maximum possible dry-bulb temperature of entering air. :: .. / Chapter 13 RAILWAY AIR CONDITIONING Ventilation, Heating, Cooling, Calculation of Cooling Load, Humidity Control, Temperature Control, Power Supply, Costs THE general principles of air conditioning as applied to buildings also apply to railway cars, but due to space and weight limitations and the severity of the service, equipment designed for stationary work in buildings is seldom suitable for car installations. Equipment for railway use must be safe, reliable, compact, light in weight, accessible for inspec tion and repairs, as nearly automatic in operation as possible, and have low initial, operating, and maintenance costs. To properly air condition a car, ventilating, filtering, heating, cooling, humidifying, and control equipment must be provided together with an adequate power supply. Air from the interior of the car. is mixed with air from the outside and passed through the air conditioning unit where it is heated or cooled, humidified or dehumidified and delivered to the interior of the car through suitable ducts and grilles. ' VENTILATION One of the important problems in connection with air conditioning of cars is that of ventilation. In non-air conditioned cars, ventilation is accomplished by exhaust fans, roof ventilators and open doors and windows. This provides an ample supply of outside air and in addition a large amount of smoke and dirt which may be excluded in an air con ditioned car. An average car contains approximately 5000 cu ft of air which is being contaminated by the occupants who are continually liberating heat, carbon dioxide, moisture, odors, and some organic matter from the breath, skin and clothing. The heat and moisture can be removed by cooliiig and dehumidifying, but the others can be handled only by proper ventilation. In the average car from 2000 to 2500 cfm of air should be delivered by the air conditioning unit. Some of this air may be re circulated, but a portion of it should be brought in from the outside. The amount of outside air required depends upon the type of .car (dining, club, cafe), number of passengers, air temperature, humidity, smoke, and odors, and will vary from 15 to 90 per Cent. This percentage of outside air should be kept as low as possible to still maintain the air in the proper condition in order to minimize the heating or cooling load. In equipping old cars, the air is often distributed to the car from the conditioning unit through one or two side ducts, built on the outside of 257 ,/ American Society of Heating and Ventilating Engineers Guide, 1936 monitor-roofed cars and on the inside of turtle-back or arched-roof cars. In some instances, a center duct is used and in others the air is discharged directly from the conditioning units into the upper part of the car either through the end bulkheads or from a unit placed overhead in the center of the car. For details of air distribution and duct design see Chapters 19 and 20. Care should be taken to keep the air velocity in the ducts below the point where the noise would be objectionable. Suitable grilles should be used at duct outlets to reduce the velocity and to direct the air so as to insure thorough mixing without objectionable drafts. The incoming air should be introduced as near room temperature as possible and should have a velocity of not over 120 fpm when it reaches the passengers. The outlet grille nearest the recirculating air grille should deflect 45 deg in one direction towards the center of the car to prevent the incoming air from passing directly to the recirculating grilles. The other outlet grilles installed along the ducts should deflect a portion of the air 45 deg to the right and 45. deg to the left and to all points between. . Smoking rooms present a special problem. The cloud of smoke that usually hangs near the ceiling 'can be broken up by having the incoming air directed along, the ceiling in all directions at a velocity somewhat higher than that used for the rest of the car. The air should be exhausted from the room by a fan or through a grille to- the wash room or lavatory, to be exhausted to the outside through a ventilator. For compartments a supply duct outlet grille of-/suitable size and design should be provided and provisions made in the door or partition for removal of the recirculated air through a special grille, which will allow the air to pass from the room to the main recirculating air grille. The exhaust grille should be designed and arranged so as to obstruct the vision of passengers. : - Lower berths in sleepers and office cars should be provided with an adjustable air qutlet which wijj.discharge the amount,of air desired at low velocity in any direction so tha.t the occupant can regulate the ventilation to meet his own.requirements., .. Recirculating air grilles are usually of the straight-flow .type, arranged to hold two 2 by 16 by 20 in. filters and hinged on an angle iron frame to permit easy, access for cleaning and repairs. They should be located so that objectional drafts will not be created by the return air.. The outside air intakes should be of ample size and provided with filters and dampers or shutters for regulating the amount of outside air. / In .cars1 containing but.one or two rooms or compartments, satisfactory results may be obtained by discharging the air directly, from the con ditioning unit into the upper part of the car. Cars must,.be taken to have a proper discharge velocity. If the velocity, is too low, the.air will drop before reaching the end of the car and if too high it will discharge against the end bulkhead and be. reflected back. Greater care must, be exercised to secure proper circulation without more objectional drafts than when ducts are used. . . .v Filters made of metal- wool, spun glass, hemp, paper, cloth, and wire screen are in use. Some types may be cleaned, retreated- and returned to service.while other types are discarded when dirty. .. 258 Chapter 13--Railway Air Conditioning HEATING The majority of cars in service are heated by circulating low pressure steam or vapor through pipes located along the side walls near the floor. When an overhead air conditioning unit, using air from the outside and discharging it into the car, is installed it is necessary to provide a heating coil to warm the air during cold weather. Most of. the heat required in the car can be supplied by the overhead unit but in extreme weather some heat must be supplied at the floor to keep the lower part of the car at a comfortable temperature. It is also desirable to...have sufficient floor radiation to keep the car from freezing up while standing in the yard with the kir conditioning unit shut off. Usually from 30 to 40 per cent of the heat required is supplied from the overhead unit and the balance from the floor heating system. The amount of heat required depends upon the type and construction of gar, especially the amount and kind of insulation, outside temperature, wind velocity and direction, train speed, number of passengers, and inside temperature desired. In severe weather, --10 to ^-20 F, an average of approximately 200 lb of steam per car per hour is required. Pullmans will require approximately 250 lb per hour, coaches 150 to 175 lb and baggage cars 150 lb. ; COOLING * - .. Three general types of cooling or refrigerating equipment are being used with satisfactory results. These are the ice, steam jet, and mechanical compressor systems. These systems when arranged for car use, function the same as in stationary service, but must be more compact and lighter in weight. See Chapters 2 and 10 for the general principles of tie various systems. The mechanical compressor systems are divided into two general classes, the direct drive and the electro-mechanical, differing.only in the method of driving the compressor. With the direct drive system, the compressor'is driven from the car axle.through a combination of pulleys, belts, gears, a shaft, and a. speed control device. With the electro mechanical system the compressor is driven by an electric motor. The refrigerant most commonly used in the mechanical, compressor systems is Freon. . Another type _of . system which has possibilities of being adapted to railway air conditioning uses methylene chloride as the refrigerant, dry ice, and a small circulating pump in place of the conventional compressor. The refrigerating unit consists of a condenser built into an insulated dry ice box. The methylene chloride is liquified by the low temperature produced by the dry ice and is circulated by the pump through the evaporator coils where part of it is vaporized by the heat from the air passing over the evaporator coils. The mixture of gas and liquid passes back to the condenser where the heat is removed and the gas liquified. This system will probably not- offer many possibilities until an adequate supply of dry ice can be assured at a stable and reasonable price. A system using a compressor driven by an internal combustion engine operating on propane has also been considered for railway air conditioning. The engine, compressor, condenser, starting motor and battery are . 259 American Society of Heating and Ventilating Engineers Guide, 1936 mounted together in a single unit and supported on a track on the car under-frame on pneumatic supports. Propane fuel sufficient for several days operation is carried in three drums mounted in a rack under the car. Freon is used as the refrigerant. The unit may be used with a direct expansion air conditioning unit or it can be used with a heat exchanger with cold water cooling coils. The capacity required in the refrigerating system depends upon a number, of factors such as size and type of construction of car, thickness and kind of insulation used, amount of heat produced within the car by motors, lights, and other appliances, amount of outside air, outside air temperature and humidity, intensity of solar radiation, number of pas sengers, and inside temperature desired. A check of a number of cars with ice-activated systems indicates an average ice consumption, day and night, of approximately 275 lb per hour.. This means an average capacity of 3.3 tons of refrigeration. It has also been observed on test that in the sunshine with an outside dry-bulb temperature of 85. to 90 F and a wetbulb temperature of 73 to 75 F, a six ton compressor unit operates ap proximately 50 per cent of the time. As the average temperature during the cooling season is below 90 F the observed performance of the six ton compressor unit compares with the 3.3 tons average capacity determined for the ice systems. It was also observed on test that with temperatures above 90 F, high humidity, and in the sunshine, a six ton unit operates almost continuously. The sun load on a bright sunshiny day is about one ton. For average cars on sunshiny days, with high temperatures and humidity, from 65,000 to 80,000 Btu per hour will have to be removed from the interior of the car to maintain an inside effective temperature within the comfort zone. This means that a refrigerating capacity of from 5.5 to 7 tons will be required. CALCULATION OF COOLING LOAD Due to the many variables involved the calculated heat gain will be more or less of an approximation, but if a careful study is made, results sufficiently accurate for all practical purposes.may be obtained. The following example illustrates a typical cooling load calculation. Example and Solution. '" J^ Type of car Roof area = Arched-roof steel coach. = 70.3 X 12.5 = 880 sq ft. Floor area = 70.3 X 9.8 \ , , = 687 sq ft. . , Window area = 38 X 2.5 X 2 = 190 sq ft. Net side wall area = (2 X 7.5 X 70.3) --(190) = 865 sq ft. End area = 2 X 7.5 X 9.8 ^ = 147 sq ft. Average roof section: 34 s in. steel sheet, 1 layer tarpaper, 2 in.air space, 34 in. hairfelt, 34 in. rigid fiber board insulation. ' - . Average window section: two layers of )4 in. glass with 1)4 in. air space between. Average floor section: 1 in. composition, 346 in. steel, 34 in. air space, 1 in. hairfelt, 34s in- steel. Average side and end section: 34 6 in. steel, 34 in. hairfelt, 3 in. air space, 34 in^wood. End area is taken as total area at body and bulkheads with no allowance .made for glass as car is vestibuled and glass in body ends is not subjected to direct solar radiation. Outside dry-bulb temperature Outside wet-bulb temperature to = 95 F. t'o = 75 F. . / 260 Chapter 13--Railway Air Conditioning Outside effective temperature ET0 Outside relative humidity rho Inside dry-bulb temperature t Inside wet-bulb temperature t' Inside effective temperature ET Inside relative humidity rh Density of air at t d Moisture per pound of dry air at to and t'o Go Moisture per pound of dry air at t and f G = 83 F. = 40 per cent. = 80 F. = 66.5 F. = 73.5 F. =50 per cent. = 0.07356. = 99 grains. =77 grains. Moisture per pound of dry air to be removed M 7Q00 70Q0 Evaporator condensate temperature = 53 F. Latent heat of water at 53 F L = 1060 Btu per pound. Specific heat of air Cp = 0.241. Number of seated passengers Pa = 68. Number of attendents Pa = 1 Heat given off by each passenger = 400 Btu per hour. Heat given off by attendent -- 650 Btu per hour. Outside air introduced Q -- 500 cfm. Roof temperature in sun = 40 F above ambient. . Wall temperature in sun = 25 F above ambient. Sun. 15 deg from Zenith. 0.00314 pounds. Solar heat = 4.75 Btu per minute per square foot. 30 per cent of heat passing through glass is reflected and reradiated, 70 per cent remaining. 80 per cent of heat at surface passes through glass. Then 4.75 X Sine 15 deg X 0.8 X 0.7 = 0.7 Btu per square foot per minute passes through glass. Evaporator motor = 34 hp. Evaporator motor efficiency = 65 per cent. The total heat gain will include the gains from leakage through roof, floor, side walls, end walls, windows, sensible and latent heats from outside air, heat from occupants, heat from evaporator fan motors and solar radiation. - Calculation of Transmission Coefficients. (See Chapter 5.) Roof coefficient = UT = Btu per hour per square foot per degree Fahrenheit. Outside air film fo = 3.5 1 // = 0.286 3^6 >n- steel k = 308 X 0.0625 IT 308 = 0.0002 2 in. air space a =1 l/o = 1.0000 34 in. hairfelt . k = 0.25 X 0.5 k 0.25 = 2.0000 34 in. rigid fiber board insulation k = 0.33 X 0.125 T 0.33 = 0.3800 , Inside air film fi = 1.65 1 // = 0.608 . Total = 4.4287 u r _1 4.4287 _ 0.232 Btu per hour per square foot per Fahrenheit. Side and end wall coefficient = Us = Btu per hour per square foot per degree Fahrenheit. Outside air film 346 in. steel 34 in. hairfelt 3 in. air space = 0.2860 k = 3.08 X 0.1875 k 308 = 0.0006 k = 0.25 X 0.5 k 0.25 = 2.0000 a =1, l/o = 1.0000 261 of andAmerican Society Heating Ventilating Engineers Guide, 1936 % in. wood k = 0.8 = 0.9350 Inside air film Total . = 0.6080 = 4.8296 Us = v oLa's = 0.207 Btu per hour per square foot per degree Fahrenheit. 4.8296 . Window Coefficient = Uv = Btu per hour per square foot per degree Fahrenheit. Outside air film )4 in. glass 1J4 in. a*r space ) in. glass Inside air film k = 1.13 a = 1.06 . l/k 1/a = 0.286 = 0.889 = 0.940 = 0.889 = 0.608 Total = 3.612 Uw -- o.OIa = 0.278 Btu per hour per square foot per degree Fahrenheit. Floor Coefficient = U{ -- Btu per hour per square foot per degree Fahrenheit. Outside air film Hs in- steel in- air space 1 in. hairfelt Ms in. steel 1 in. composition Inside air film a = 1.2 k = 0.25 k =6 l/o = 1/1.2 l/k : l/k = 0.2860 = 0.0002 = 0.8320 = 4.0000 = 0.0002 = 0.1666 = 0.608Q Total , = 5.8930 Ui = . = 0.170 Btu per hour per square foot per- degree Fahrenheit. ; . . 5.893 ' ' . -' Heal Leakage: Through roof = 880 X 0.232 = 204 side walls = 865 X 0.207 = 180 floor = 687 X 0.170 =. 117 .' windows = 190 X 0.278 = 53 end walls = 147 X 0.207 = 31- . 585 Btu per hour per degree Fahrenheit. Total heat gain = 585 ,(<o -- t) = 585 X 15 = 8775 Btu per hour. . Sensible heat gain froiti make-up air = Q X 60 X d X Cp X (fo -- 0 = 500 X 60 X 0.07356 X 0.241 X 15 = 7950 Btu per hour. Latent heat gain from outside air = Z.X60XQXdX.M' = 1060 X 60 X 500 X 0.07356 X 0.00314 = 7350 Btu per hour. Heat gain from passengers = (68 X 400) + (1 X 650) = 27:850 Btu per hour. . Heat gain from evaporator motor = X 0.746 X 3415 = 1960 Btu per hour. . ' Heat gain from solar radiation: ' - '/' ' . Heat gain through roof = Ut X At X 40 = 0.232 X 880 X 40 = 8150 Btu per hour. Heat gain through side wall = 0.207 X 433 X 25 = 2230 Btu per hour. 262 Chapter 13--Railway Air Conditioning 190 Heat gain through window = 0.7 X X 60 = 4000 Btu per hour. Total heat gain from solar radiation = 14380 Btu per hour. Summary of Total Heat Gains: Leakage Sensible heat from outside air Latent heat from outside air Heat from passengers Heat from evaporator fan motors Solar radiation 8,775 7,950 7,350 27,850 1,960 14,380 Total 68,265 Btu per hour. This would require a refrigerating capacity of 12'qqq = 5.7 tons. HUMIDITY CONTROL The temperature to be maintained in a car depends upon the outside temperature and the desired humidity inside the car. With a low hu midity it is necessary to maintain a higher temperature to establish a desirable comfort condition. Little humidity control has been attempted on cars up to the present time. A certain degree of automatic humidity control is secured with cooling, but the relative humidity obtained depends largely on the temperature of the evaporator, which should be below the dew point temperature of the air. With certain outside atmospheric conditions it may not be possible to operate the conventional equipment with a sufficiently low evaporator temperature to reduce the humidity without dropping the temperature too low. One method has been developed whereby the evaporator temperature is carried below the dew point a sufficient amount to insure dehumidification and then the.cold air is heated to the proper temperature by passing it over coils through which part of the high temperature liquid from the compressor is bypassed. During the heating season humidification is desirable from a. comfort standpoint, but the proper amount of humidification required would doubtless cause the windows to become frosted. A steam or water spray controlled.by a humidistat will provide the necessary moisture if humidi fication is desired. ' TEMPERATURE CONTROL .The control of the air conditioning equipment should be simple but at, the same time as nearly automatic as possible. The use of a centralized, control panel for all control switches, fuses, relay, etc., will simplify the installation and operation. Generally, separate thermostats are used for ' heating and cooling control. The best location for the thermostats depend upon the car layout and method of air distribution and can best be determined for any particular type of car and equipment, by. careful consideration of the several factors involved. The floor heat thermostats are usually located near the floor. The overhead heat and cooling ther mostats are placed in the upper part of the car, sometimes in the air ducts. All thermostats should, be located so that the air can circulate freely around them. Maintenance of uniform comfort conditions for cooling, 263 of andAmerican Society Heating Ventilating Engineers Guide, 1936 floor.and overhead heating, has been satisfactory with provisions for high, medium, and low thermostat settings and in some cases, two settings have been satisfactory for cooling. In many cars the following points have been found to be satisfactory, 71 and 76 F for cooling, 60, 71 and 74 F for floor and overhead heating. The heating and refrigerating equipment should be interlocked so that they cannot both operate at the same time. While heating, the control should be so arranged that in case of a steam failure the blower fan will stop or the outside air intake closed to prevent cool air from being intro duced into the conditioned space. POWER SUPPLY One of the most important problems to be solved in connection with railway car air conditioning is that of power supply. The majority of cars now in service are electric lighted and equipped with fans. Power is furnished by storage batteries and axle generators of from 2 to 5 kw capacity. When air conditioning is installed the electrical load is in creased approximately 1 kw for ice systems, 3.5 kw for steam systems and 10 kw for electro-mechanical compressor systems. Steam ejector systems require approximately 230 lb of steam per car per hour for a six ton unit. All of this power as well as the power required to move the extra weight must be supplied by the locomotive enroute and if a number of cars in the train are air conditioned, the effect on train performance should not be overlooked. In the case of mechanical compressor systems the power is taken from the locomotive draw bar, unless the compressor is driven by an internal ' combustion engine, while with the steam system most of the power is furnished in the form of steam which is a load on the locomotive boiler but not on the cylinders. The ice system takes the smallest amount of power from the locomotive since no power is required to produce refrigeration. The demand for power for cooling comes, however, at the time of year when steam for heating is not required and the demand for. lighting is at a minimum. ; Inasmuch as axle generators and mechanical driven compressors will not operate below a certain cut in speed and will not carry full load until a speed considerably higher than cut in speed is reached, it is quite apparent that the characteristics of the. run such as schedule speed, top speed, number of stops, length of stops, percentage of time of operation at slow speed, length of run, etc., must be considered in the selection of equipment. Fig. 1 shows the tractive resistance of a 75 ton car with six wheel trucks without an axle generator, and with a 4 kw generator and for the same car with ah increase in weight of five tons, and with a- 20 kw axle generator load. . The direct-drive compressor system has only the friction of the drive during starting and at low speeds. After the compressor cuts in the load increases with the speed. The compressor output increases with the speed until maximum output is reached and then the drive efficiency decreases as the speed continues to increase so that the power input to the drive continues to increase and, the greater power requirements Qome at the higher speeds. . 264 Chapter 13--Railway Air Conditioning Consideration must. also be given to the power requirements for refrigeration while the car is at a standstill or running at slow speeds. The electrical energy required for the ice activated and steam systems is easily supplied from the storage battery. With the ice system a supply of ice is necessary and steam for the steam system can be supplied from the locomotive or from a stationery plant. The majority of the electro mechanical systems are equipped with A.C.--D.C. motors. While standing in the yards and stations the A.C. motor is connected to a 220 volt, 3 phase circuit. The majority of these equipments are so arranged that while operating on A.C. power the D.C. motor may be used as a generator for battery charging. If an auxiliary circuit is not available the D.C. compressor motor may be operated from the storage battery. Fig. 1. Tractive Resistance of 75 Ton Passenger Car with Six Wheel Trucks The direct drive mechanical compressor systems are also equipped with A.C. motors for operation from auxiliary circuits. These equipments can only be operated when connected to the auxiliary circuit or while the train is running above the cut in speed of the drive. COSTS It is rather difficult to calculate the costs of car air conditioning due to the many variables involved. A study of reports covering a large number of cars of all kinds, operating under various conditions in all parts of the country, indicate a great variation in costs and weights for all systems. The following tabulation shows the average values for all cars considered. Av. cost Av. weieht.... Av. maintenance per 1000 car-miles Av. ice caDacitv. Av. ice consumption per hour Ice $4000.00 8500 lb $2.00 4500 lb 275 1b Steam $8200.00 11300 lb $2.20 Mech. Comp. Electro $8200.00 96001b $3.85 Direct . ' Drive $8200.00 86001b $3.22 American Society of Heating and Ventilating Engineers Guide, 1936 Based on an average cost of coal, water and locomotive lubrication of $0.001133 per pound of fuel burned and the following assumptions: generator and drive efficiency 80 per cent, locomotive mechanical ef ficiency (cylinders to tender drawbar) 90 per cent, 3.5 lb coal per cylinder horsepower and 6 lb of water per pound of coal, the cost of generating 1 kw of electrical energy would be $0.00738, and 100 lb of steam $0.01888. This is based on the assumption that the cost of coal, water and loco motive lubrication would increase in direct proportion to the amount of coal burned. As the cost of locomotive lubrication would not increase in direct proportion to the amount of coal burned, the extra cost of lubri cation included in the figure should offset the increase in cost of loco motive maintenance due to the additional load. Using an average capa- Fig. 2. Costs Railway Passenger Car Air Conditioning city of 3.3 tons, the cost per hour of operation would be approximately $0.04 for steam and mechanical compressor systems and $0.55 for ice, using a price of $4.00 per ton for ice. . . .. These figures are based on the assumption that the motor driven c6m- pressor is receiving power direct frorri the generator and that the efficiency of the direct drive is the same as the combined efficiency of the axle generator, drive, and motor. Of course part of the current for the \ electric drive would be taken from the battery and therefore the battery C efficiency would, have to be taken into consideration. Likewise the lower efficiency should be considered of the direct drive at the higher speeds and it would be necessary to know the characteristics of the run under con sideration to make an exact comparison. -, For a given run the total kilowatt hours required for the electro mechanical; system would . ~ _ EgXlgXTg Eb X lb X Tb *, . " 1000 + eb X 1000 ' where ' Eg = voltage with generator cut in. ......Eb = voltage with generator cut out. ......... ,. 1 - 266 | ___' Chapter 13--Railway Air Conditioning /g = current with generator cut in. /b = current with generator cut out. Tg = time generator cut in. 7b = time generator cut out. ,eb = battery efficiency. . C_ylind,er ,horsepower .hour = kiglog wXatetdhXourest XX 7140600 . . where eg -- generator efficiency. c& = drive efficiency. , Ci = locomotive mechanical efficiency. . With these formulae and the coal and water rates of the locomotive the total amount of fuel and water required to supply the power enroute can be calculated. Fig. 2 shows the relation between the cost per thousand car miles and total miles run per year for the ice and electro-mechanical systems. These curves are based on the cost figures previously given and the follow ing formula: where c-ost per rnousana car miles CM XD 45 A = Annual fixed charges (dollars) calculated as follows: a. Depreciation b. Interest e. Taxes and insurance 12.5 per cent 6.0 per cent 1.5 per cent Total CM = thousand car-miles per day. D = days in service per year. M maintenance cost per thousand car miles. C = operating cost per hour. ' 45 = average miles per hour. 20.0 per cent No charges for precooling are included. The curves for the steam and direct drive mechanical compressor systems would be between those shown for the ice and electro-mechanical compressor systems. PROBLEMS IN PRACTICE 1 What is the capacity of the air conditioning unit in the average car? 2000 to 2500 cfm. . 2 How much steam is required for car heating on the coldest days? ' Pullmans 250 lb per hour, coaches 150 to 175 lb per hour, baggage cars 150 lb per hour. 3 What types of cooling systems are used? Ice, steam jet, and mechanical compressor systems. 267 f(t,* crjt'rjwyriif- of and 1936American Society Heating Ventilating Engineers Guide, 4 What refrigerating capacity is required? . 5.5 to 7 tons per car. 5 'What would be the annual operating cost for a car cooling system, using ice, if the car travels 150,000 car miles?- * $2,850. \ 268 '*' ' Chapter 14 TEMPERATURE AND HUMIDITY CONTROL Apparatus Sensitive to Temperature, Apparatus Sensitive to Relative Humidity, Accessory Apparatus, Temperature Control Systems, Control of Automatic Fuel Appliances, Individual Room Control, Zone Control, Industrial Processes, Air Con- ditioning Systems AUTOMATIC controls can be installed on any type of heating, ventilating, or air conditioning system to maintain desired con ditions automatically, and with maximum operating economy. The variety of automatic control' equipment available is such that a suitable control system can be devised without difficulty, provided that the con ditions to be maintained are known and the control equipment is properly chosen. This chapter outlines briefly the various types of control appar atus and indicates the method of their application to typical heating, ventilating, and air conditioning systems. Specific control devices and systems are described in the Catalog Data Section of The Guide. Controls are applied for the following reasons: 1. To maintain conditions required for human comfort and efficiency. 2. To maintain conditions, required for industrial processes.3. To obtain economy in operation. 4. To provide necessary safety measures. CONTROL APPARATUS The various pieces of control apparatus may be grouped under the following general headings: .......................... Apparatus Sensitive to Temperature: Temperature-sensitive devices which will respond to changes in tem perature, and which will motivate equipment to compensate for the changes, are usually called thermostats. They have many specialized forms for use in specific control' applications. Thermostats are the detectors of a control system which-identify changes in desired'tempera ture conditions and automatically call for compensating action. Thermostats are actuated by various means, all of which have thecommon characteristic of responsiveness to small changes of temperature. The actuating element may be a piece of bi-metal in straight, helical; or spiral form (Fig. 1), which, by bending slightly as. the temperature changes, actuates an electric or pneumatic switch to govern the controlled 269 of andAmerican Society Heating Ventilating Engineers Guide, 1936 apparatus; or the actuator may be a diaphragm, bellows, or tube filled with a volatile liquid (Fig. 2) in such way that expansion and contraction with changes in temperature will operate the controlled apparatus by a direct mechanical, electric, or pneumatic connection. A room or wall thermostat in its simplest form contains a single tempera ture-sensitive element which is so set that it maintains, by actuating the controlled system, a single temperature. A variation of this is the twotemperature or dual thermostat having two temperature-sensitive ele ments, one of which is set for a higher temperature than the other. Such a thermostat is used on day-night systems where the night temperature Fig. 1. Typical Bi-Metallic Thermostatic Elements Fig. 2. Diaphragm Type Thermostat is to be lower than that maintained during the daytime hours. Switching the control from one element to the other is accomplished by an external or an internal switch, which can be operated manually or by a time device. Duct type thermostats are used in systems where the equipment must, respond to changes in the temperature of the air passing through a duct. In their usual form, these thermostats are so constructed that their switching mechanism is outside the duct, while the temperature-sensitive element projects inside into the air stream. . Thermostats which operate in liquids have the same general construc tion as duct thermostats except that the sensitive element is usually 270 Chapter 14--Temperature and Humidity Control enclosed in a tube to keep it from direct contact with the liquid. They are used in pipes, vats, and tanks, and are called immersion thermostats. Sometimes surface thermostats are used in place of duct or immersion thermostats. These devices, so constructed as to respond to changes in temperature of the surface of the duct or vessel containing a fluid, are clamped or screwed to such surfaces in a manner which will provide as rapid as possible heat transfer between the surface and the sensitive element. Other forms of thermostats are available for specialized purposes, but those described previously are the ones in general use for heating, venti lating and air conditioning systems. Apparatus Sensitive to Relative Humidity Devices which are responsive to changes in the relative humidity of the surrounding air, and which will motivate equipment to compensate for the changes, are called humidistats or hygrostats. These may vary , con siderably in their sensitive elements, but they all operate through con necting equipment which automatically causes humidifying apparatus to supply more or less moisture as required. Some of the more complicated ones contain essentially two thermostats, one working on a dry-bulb temperature and the other on a wet-bulb temperature; by proper inter connection of th$ parts they operate to maintain a definite relation be tween these two temperatures. Other devices use elements, directly sensitive to humidity, made of special wooden blocks, human hair, fiber, membranes, or strips of prepared paper. Hygrostats are available for, use with both electric and pneumatic control systems. Apparatus Which Operates Valves Apparatus which is so mechanically or electrically equipped that it will open and close valves, and possibly give them intermediate positions in any pipe line of a heating, ventilating, or air conditioning system, is termed a valve operator. The function of a valve operator is, essentially, to move the plunger of a valve in a manner required by its type and construction. For instance, in a single-seat valve, the disc is moved against the seat and held there with sufficient pressure to prevent flow. A three-way valve, however, requires a valve operator that will place the double disc, as required, between the two seats. Each type of valve has special characteristics to which a valve operator must be adapted. When a valve is used in shut-off service the valve operator simply opens the valve or closes it completely, as required. When the valve is to provide throttling service, a different type of valve operator is used so that the valve may be held at any intermediate position between open and closed. Valve operators use as their power source either compressed air (pneumatic system), electricity (motor-driven type or solenoid type), or a volatile liquid (direct-connected type). Apparatus Which Operates Dampers Apparatus which is so mechanically or electrically equipped as to open .and close dampers, and possibly give them intermediate positions, in accordance with the purposes of the system using the dampers is termed 271 of andAmerican Society Heating Ventilating Engineers Guide, 1936 a damper operator. Damper operators are made for opening, closing, and positioning the dampers in the ducts of heating, ventilating, or air con ditioning systems in the same way that valve operators regulate the valves. They are controlled from thermostatic or manual switches. The sources of power used are compressed air, electricity, or volatile liquids. The damper operator is connected to its damper by direct con nection or by a linkage, according to conditions, and it can usually be' mounted either outside or inside the duct in which the damper is located. Accessory Apparatus Accessory apparatus is that additional equipment at the terminals of a control system necessary to make it operative. Every temperature con trol system requires a number of accessories, which will vary with the different types of systems. For instance, pneumatic systems require a compressor and a storage tank for the air which operates the units, and low-voltage electric systems require a transformer or generator to provide the required current. . Most of the larger control systems will have some sort of central switch board which may include indicating and recording devices as well as control switches. Thermostat guards are generally used in gymnasiums, schools, and places of assemblage for protective purposes. Time switches and similar devices are often important parts of certain types of control systems. Couplings, mountings, and indicators are often parts of a system. . Connecting Apparatus . Connecting apparatus is that equipment used to connect the various parts of a Control system. Because the parts of the system are often some distance apart, the connecting means are importanc, and the. connections must be properly planned and made. '. : The connecting elements are fairly obvious. The pneumatic system uses compressed air carried in small pipes and tubing. Electric systems are wired for low-voltage or high-voltage power supply. Systems em ploying volatile liquids generally use flexible tubing if there is distance between the sensitive bulb and the operating unit. Each form has certain limitations which the designer of the system must consider. . Since few control installations are alike, the. manufacturers of control apparatus usually maintain engineering\departments staffed by experi enced men whose advice may be had on control problems.- Progress in automatic control has been rapid in the past few years and the field has become highly specialized. . TEMPERATURE CONTROL SYSTEMS Control of Radiators or Convectors The control of direct radiation is simple. Each radiator has a valve on -its steam or water supply, with a thermostat to govern the opening and closing of the valve to maintain the desired uniform temperature as shown in Fig. 3. One thermostat may control the valves on all the radiators in a room, or, if the room is large, more than one thermostat may be used, with 272 14--Chapter Temperature and Humidity Control each one governing one radiator or a group of them. Unit type ther mostatic valves may be used, one on each radiator. - The location of wall thermostats is important. They must be on inside walls where they will not be affected by drafts of either warm or cold air, but where they will be exposed to general room conditions. If vibration is present, they must be mounted on shock-absorbing bases. If the walls are abnormally hot or cold, the thermostats must be mounted on heatinsulating bases. The connecting means can be concealed in the wall, under the floor or ceiling, or behind baseboards or moldings. Modulating type valves cannot be used successfully on one-pipe steam systems because the partial opening of valves will not allow the con densate to escape against the incoming steam. A discussion of steam heating systems is given in Chapter 31, and Fig. 3. Control of Direct Radiator with Room Thermostat. further information on control requirements of direct radiation may be obtained therefrom. Control of Unit Heaters Unit heaters are commonly ceiling-hung or floor-mounted units con sisting of a steam dr hot water coil with a fan behind it to force air past the coil and into the room. Vanes direct the warm air flow. The simplest and commonest way to control a unit heater is to have in the heated space a thermostat which will turn on the fan when heat is required and shut it off when the demand is satisfied. However, where there is natural circulation through the unit, it is advisable to. put a valve on the steam or hot water supply line and arrange it so the steam will be turned on only " when the fan is running. '' As a precaution against allowing the unit heater motors to continue to run if the steam supply fails or is for some reason shut off, a thermostat 273 of andAmerican Society Heating Ventilating Engineers Guide, 1936 on the return line may be installed to stop the motor when the tempera ture in the return line is below a predetermined point as shown in Fig. 4. When the fan and the steam are controlled simultaneously, such ther mostat will also prevent the blowing of cold drafts. The net result in any case will be that the fan will run only when there is heat in the coil. , Control of Unit Ventilators The unit ventilator presents a different control problem than the unit heater. Generally this type of unit draws its supply of air from the outside, heats it, and introduces this air into the room under control as shown in Fig. 5. There are many types of unit ventilators available. Some have a mixing damper by which the temperature of the air entering + Steam or hot water supply ol valve . Room Q j"j thermostat-*rn i i_______y To return surface thermostat Fig. .4. Unit Heater Control the room may be varied, others have valves for this purpose, and still others use a combination of theTwo. Regardless of the construction of the machine, the.essential requirement is that the temperature of the air delivered to the room should change slowly and remain as near room temperature as possible. Frequently direct radiators are used in con junction with the unit ventilators to supply additional heat in extremely cold weather or for quickly heating up the room. The four general types of control for unit ventilators are as'follows: 1. A damper operator, which is controlled by a room thermostat, is attached to the mixing damper. When the thermostat calls for heat, the damper, is moved to'a position which forces more air through the heating unit and thus increases the amount of heat supplied to the room. This action must be gradual so that the air temperature may be changed slowly to prevent the drafty condition caused by supplying first hot and then cold air. This simplest arrangement is often condemned because it frequently results in drafts. 2. In mild weather the heating unit frequently supplies sufficient heat to cause over heating of the room, even though all of the air is by-passed around the heating unit. To avoid this fault a valve is placed on the heating unit to close the steam supply when the damper is by-passing all of the air. This valve is used in addition to the damper operator explained in the foregoing paragraph, but though giving better results, it may fail to prevent drafts. 3. In some unit ventilators one or more heating' units are used without a mixing damper. A gradual-acting valve on each heating unit controls the supply of steam to the 274 . Chapter 14--Temperature and Humidity Control unit to give the proper amount of heat required to maintain the desired room tempera ture. A thermostat to govern each valve may be installed in the room, or one thermostat may be used for all valves, but unless a thermostat is placed directly in the air stream of each unit, drafts may be encountered. . 4. Another type of unit ventilator is arranged so that all recirculated air passes through the heating unit, and the outside air is introduced into the room for cooling purposes only. The outside air damper and the recirculated air damper are interlocked so that one damper operator will control them. In addition a valve operator is placed on the heating unit. Both of the operators should move gradually to avoid drafty con ditions. When the thermostat calls for heat, the damper operator slowly closes the outside air damper and simultaneously opens the recirculating damper: if this does not meet the demand, the valve on the heating unit opens until the room temperature reaches the desired point. Fig. 5. Control of Unit Ventilator and Radiator For additional information on the control of unit ventilators, refer to Chapter 12. . Central Fan Heating and Ventilating Systems ' The numerous types of central fan systems present many control problems. In general they all have one point in common, namely, that the temperature change may be very fast because of rapid circulation. System for Ventilating Only (Split System). Fig. 6 shows an accepted control for ventilating systems. Thermostat A located in the outside air duct is set just above freezing, and controls a valve C on the first heating coil. This valve is either completely open or completely closed. The by pass damper B and the other two valves D and E are controlled by a duct thermostat F located in the discharge duct from the fan. If the tempera ture of the air surrounding the thermostat F increases, the damper is moved automatically to admit more cold air. Should this not reduce the temperature sufficiently, the valves on the heating coil will be closed 275 ofAmerican Society Heating and Ventilating Engineers Guide, 1936 gradually and in sequence until the correct temperature is reached. The opening or closing of the damper B and the valves D and E must be .gradual or there will be a wide fluctuation in air temperature. In ventilating systems it is customary to supply air to the ventilated spaces at an inlet temperature approximately equal to the temperature maintained in the rooms. The radiators therefore are designed to take care of all the heat losses from the room. Hence, in order to maintain controlled room temperatures it is necessary to use room thermostats governing control valves placed on the radiators. With this type of central fan system it is possible to ventilate a large number of rooms by means of one fan. In some installations, such as in theaters or auditoriums, it is difficult to install sufficient direct heating surface to offset the heat losses from the room. Also there are installations where a short heating-up period is allowed before occupancy of the room, and it is advisable to use the Fig. 6. Control of a Split System of Ventilation entire heating capacity of the ventilating system for this purpose. An additional thermostat may be installed in the room to disable the duct thermostat and utilize the full heating capacity when the room is below a certain temperature, or a switch may be provided in the room or else where for this purpose. In central fan systems, air washers are bften used and in such cases, due to the effect of temperatures on humidity, additional control is required. Fig. 7 shows such an arrangement with control of the second tempering heating unit by the air washer temperature and with the usual control of the first tempering heating unit by the outside temperature. This permits the air to be kept cool while passing through the washer so that too much moisture will not be absorbed. Fig. ,7 also shows control of the reheating units by a duct thermostat in the fan discharge, and the application of a pilot thermostat to a system of this sort. Combined Systems, There are various central fan systems which are used for both heating and ventilating. They are usually arranged with tempering heating units, automatically controlled to provide a minimum temperature for ventilating only, and additional heating units to supply 276 ' insertion thermostat Fig. 7. Use of Pilot Thermostat on Ventilating System with Air Washer the heating requirements. Fig. 8 shows a type of system which has the reheating units located in the fan room. Tempered air at about 70 F is supplied to the fan. It may be further heated by the reheating units, or it may pass into the tempered air chamber. A room thermostat controls a gradual-acting damper operator on the double mixing damper in the warm and tempered air chambers. When the thermostat calls for heat, the damper operator moves the dampers so that more air is taken from the warm air chamber. It is essential that the double mixing damper be moved slowly to prevent alternate blasts of hot and cold air from being supplied to the room. Outside Air, Recirculating, and Vent Dampers. In all types of plenum systems, the outside air damper is usually opened and closed by a damper operator. This operator may be controlled from a,switch in the engi neer's room or it may be operated by a relay in the fan motor circuit. Fig. 8. Control of Mixing Dampers with Intermediate-Acting Thermostat 277 ' American Society of Heating and Ventilating Engineers Guide, 1936 When the ventilating fan is started, the relay causes the damper operator to open the outside air damper. Recirculating dampers and vent dampers may also be opened and closed by means of damper operators controlled from remote locations. Generally these damper operators are positive acting and are either completely opened or closed. However, in some cases where part out side air and part recirculated air is used, it is advantageous to use damper operators which have a certain number of definite positions. With this type of operator it would be possible to use 75 per cent outside air and 25 per cent recirculated air, or any other proportions which might be predetermined. These damper operators are controlled from switches1 generally mechanically interlocked so that the total opening of the two dampers is 100 per cent. Hand-Fired Coal Systems In small buildings the heating plant may be controlled by a single thermostat located in a key room in the building, instead of each room having its own control. The most common control for a hand-fired furnace or boiler consists of a room thermostat and a furnace regulator of some type. The thermostat should be located in a representative room; never, of course, near the chimney or heat flue, too close to a radiator* or in a drafty hallway, and preferably on an inside wall. The regulator is attached to the draft and check dampers of the furnace. When the temperature of the air sur rounding the thermostat drops, the thermostat causes the furnace regu lator to open the draft and close the check damper. As soon as the room comes up to temperature, the draft is closed and the check damper opened. With this arrangement on hot water heating systems it is advisable to install an immersion thermostat in the boiler. This thermo stat should be connected with the room thermostat so that both must call for heat before the draft is opened, but either one may cause the draft to be closed. On warm air systems it is advisable to use a bonnet thermostat and on steam heating systems a pressure limiting device, in series in each case with the room thermostat. If the temperature of the heating medium becomes too high, the drafts will be closed even though the room thermostat continues to call for heat. There have been some recent improvements in controls of this type, involving the,use of special types of thermostats and auxiliary apparatus which will give closer control and prevent overheating in mild weather. CONTROL OF AUTOMATIC FUEL APPLIANCES It is essential that automatic temperature control be used with oil burners, gas burners, and stokers to aid economical operation. There are many types of burners and many types of control, but there are some points common to all. First, a room thermostat is located, in a key. position in the building to maintain a given temperature at that point. Safety devices are installed in connection with this thermostat so that a failure of the ignition, power, or fuel supply will shut the system down. The same limit controls as recommended for coal burning should, be used. ' 278 / Chapter 14--Temperature and Humidity Control Oil Burners ,, Fig. 9 illustrates diagrammatically the essentials of an oil burner con trol circuit. Three thermostats are employed as shown in the illustration. Thermostat No. 1 will stop the burner when the room temperature is too high and No. 2 will stop the burner when the temperature of the heating medium exceeds the setting of thermostat No. 2. Both temperatures must be below their respective thermostat settings to start the burner. Thermostat No. 3 responds to the flame temperatures and in conjunction with the control switch acts as a safety to stop the burner if the latter fails to ignite or burn properly as demanded by thermostats Nos. 1 and 2. Domestic Applications Steam and hot water heating plants are often used to provide heat for the domestic hot water supply as well as for heating the building. Fig. 10 Y#////////////////////////////////yy/////////y \ \ ^ ^/, UJJoinermosM Y m Living Room g^ i 1 ^ Y y. Friirrssrt Fi-iloors^ '* Y\//. Y/y///////////YY////^//Y////YYYY/YYYYY//, No.? Thermostat r->' Switch Heater htVOil Burner Motor- Y/////y F- 'No.3 Thetmaa+nl FIG. 9. Electric Thermostat Applied to Oil-Fired Heating System illustrates one such system. The burner control is similar to that shown in Fig. 9 except that either the room thermostat or the tank thermostat may start the burner. If the house is warm enough, the house tempera ture control valve will remain closed, and the boiler, through the coil heater, will warm the water in the storage tank until the tank thermostat is satisfied when the latter will close its valve and stop the burner. If the house is not warm enough when the tank thermostat is satisfied, the latter will merely close its control valve and the burner will continue to run. The burner will stop only when both thermostats are satisfied, or when the steam pressure shall have reached that allowed by the pressurestat. Much the same control is applied to gas burners and automatic coal stokers.. . '. . Gas Heating Appliances . . On account of the' ease and effectiveness with which the fuel can be controlled, gas-burning appliances are particularly adaptable to full 279 j American Society of Heating and Ventilating Engineers Guide, 1936 automatic control. Standard equipment on a steam boiler generally in cludes provision for control through a room temperature thermostat, a steam pressure regulator, and a device which shuts off the gas in the event that the water level becomes too low. Practically all gas boilers are or may be equipped with automatic safety pilots which shut off the gas if the pilot flame is too low. . Water boilers are adapted to operation under thermostatic room tem. perature control and are also provided with water temperature control equipment. Warm air furnaces can be under the control of thermostats F . 10.ig Typical Arrangement op Steam or Vapor System with Two Thermostats Controlling Automatic Fuel Burner Used for House Heating and Water Heating in the spaces being heated, as well as thermostats located in the heat ducts for the purpose of preventing unpleasantly hot air reaching the heated spaces. Variations in the pressure under which the gas is supplied to the appliance are controlled by means of a gas-pressure regulator. This is an essential part of practically all makes of gas-burning heating appliances; in fact, a gas-pressure regulator is required by the American Gas Associa-f tion on all approved gas boilers, warm air furnaces (except floor furnaces), and unit heaters. s INDIVIDUAL ROOM CONTROL The most complete type of automatic'control is that by which the temperature in each room or in a group of rooms can be controlled. A thermostat in each room governs the'valves on the radiators in that room, opening them as heat is called for and shutting them when the room is warm enough. The thermostats are all connected in relay so when'any thermostat is calling for heat, an automatic burner will supply steam, hot water, or warm air, to the system; and when all the thermostats are satis fied, the burner will shut off. This is an excellent arrangement for larger residences, and it may be applied, in modified form, in houses which have one room or a section that is difficult to heat. 280 Chapter 14--Temperature and Humidity Control ZONE CONTROL Zone control is a step between a single thermostat and individual room temperature control. The building is first divided into sections or zones which may have quite different heat requirements. With this method of control: First: The zoning should be done with reference to the compass, since the north and west quarters in most localities require considerably more heat during the heating season than do the south and east quarters. Second: Most large office buildings have more or less space occupied by merchants, and some by clubs, or restaurants, which have short hours of occupancy. Much can be accomplished in zoning with reference to the kind of occupancy of space. For additional infor mation on this subject, refer to Chapter 31. Variations of the usual zone control methods by the use of recently developed special devices have been quite successful in obtaining greater economy from heating systems. Frequently these use an outside ther mostat or group of thermostats which adjust the operation of the controls to conform to variations in weather-conditions. COOLING UNITS Cooling units are readily adaptable to thermostatic control. Several arrangements are as follows: 1. Room thermostat in conjunction with a magnetic or motor-operated valve to regulate the flow of refrigerant to coil. Usually the fans operate continuously. 2. Room thermostat to control the operation of the compressor. The fans operate continuously. 3. Room thermostat to control the operation of the fan motors. 4. Room thermostat to control the operation of the fan motor and the compressor motor simultaneously. 5. Room thermostat to control the operation of the compressor with back pressure control to regulate the fans. INDUSTRIAL PROCESSES There are many industrial processes requiring automatic temperature and humidity regulation. The control equipment operates on the same principles that have been described, but it is often especially designed for each particular process.. Each installation,, or the installation for each process, is likely to be a problem peculiar to that process. AIR CONDITIONING SYSTEMS The following fundamental principles should be borne in mind in the solution of problems involving the control of air conditioning systems: 1. Dew-point temperatures vary only with the amount of moisture. That is, no matter how much a given mixture of air and water vapor is heated or cooled, the dew point temperature remains the same, as long as there is no addition or subtraction of water. Cooling below the dew-point temperature will, of course, cause condensation: of the water vapor. Also, at the same temperature, there is always the same proportion of. 281 American Society of Heating and Ventilating Engineers Guide, 1936 water vapor in the saturated mixture, provided sufficient water and time are furnished for saturation. . Table 5, Chapter 1, shows the amount of moisture required to saturate a space at various temperatures. When the proper amount of moisture is determined, it is only necessary to set the air washer (dew-point) thermostat for the corresponding temperature of saturation; then if the air entering the washer has more humidity than desired, the excess will be condensed; and if it has less, the deficiency will be absorbed from the sprays. For example, the dew-point temperature at 70 F and 40 per cent relative humidity is 45 F. Therefore, if the air temperature is maintained at 45 F as it leaves an air washer (assuming it is fully saturated) and then is heated to 70 F, it will have a relative humidity of 40 per cent. If it is desired to maintain these conditions in a given space, the air tem perature can be raised to any necessary point, say 120 F (at which the relative humidity will be only 9 per cent). When the heat in the air has been dissipated, the space tem perature being maintained at 70 F, the relative humidity will be 40 per cent. 2. Within ordinary operating ranges, saturated air will have a relative humidity of approximately 50 per cent when its temperature is raised 20 deg. For example, satu rated air at 40 F raised to 60 F has a relative humidity of 48 per cent; 60 F saturated air raised to 80 F has a relative humidity of 50 per cent. (See Table 4, Chapter 1.) Thus a differential thermostat can be used to maintain a nearly constant relative humidity of 50 per cent by holding the dew-point temperature 20 deg below the dry-bulb temperature. 3. The total heat of the air and the water vapor mixed with it varies directly with the wet-bulb temperature. For example, the occupants of an auditorium give off sensible heat which tends to raise both the dry-bulb and the wet-bulb temperatures of the space ; but the occupants also give off moisture which increases the absolute humidity and tends to further raise the wet-bulb temperature by an amount which is a direct indication of the heat expended by each occupant in evaporating this water. This relationship is useful in regulating the total heat, as wet-bulb temperatures can be controlled directly by means of a thermostat having a sensitive element covered with water-fed wicking, similar to a wet-bulb thermometer. For example, the total heat of air at 80 F and 60 per cent relative humidity is the same as for air saturated at 70 F, i.e., 33.96 Btu per pound, both having a wet-bulb temperature of 70 F. Air at 80 F and 60 per cent relative humidity (70 F wet-bulb = 33.96 Btu per pound) reduced to 70 F and 50 per cent relative humidity (58)^ F wet-bulb = 25.37 Btu per pound, total heat) must give up 8.59 Btu per pound. If the sensible heat and mois ture pick-up in an auditorium is 8.59 Btu per pound of air handled in the conditioning system, the wet-bulb temperature of the air entering the space must be maintained at 58H F to secure a final condition of 80 F and 60 per cent relative humidity. Control of Relative Humidity The following are the most commonly used methods of controlling relative humidity: 1. A thermostat is located in or at the outlet of a spray-type air conditioner which maintains a constant saturation temperature of the air leaving the conditioner by varying the temperature of water entering the suction of the pump supplying the spray nozzles, or by varying the temperature of the air entering the conditioner, or both. The tempera ture of the air entering the conditioner may be varied by use of tempering heaters, or by the proper proportioning of supply and return air entering the conditioner. This thermo stat is known as a dew-point thermostat, as it determines the dew-point temperature of the air introduced into the conditioned spaces. A second thermostat in the room, or in the path of the air leaving the room, maintains a constant dry-bulb temperature by varying the amount of sensible heat added to the air leaving the conditioner, or by varying the volume of air introduced, into the conditioned spaces. These two ther mostats, in combination, control the dry-bulb and' dew-point temperatures, which accordingly fix the relative humidity. `, 2. A wet-bulb thermostat is located in the room, or in the path of the air leaving the room, to maintain a constant wet-bulb temperature by varying the saturation tempera ture at the air conditioner outlet. A dry-bulb thermostat is located in the rootn to maintain a constant dry-bulb temperature, which in combination with a constant wet- bulb temperature fixes the relative humidity. . 3. A differential thermostat may be used to control relative humidity.. This instru ment consists of two thermostatic elements, one of which is in the path of the air leaving Chapter 14--Temperature and Humidity Control the conditioner, and the other under the influence of the dry-bulb temperature in the room. Instruments of this kind maintain a constant relative humidity by maintaining a constant difference between the dew-point temperature and the dry-bulb temperature in the room. (See Item 2 under Air Conditioning Systems.) One thermostatic element may be equipped with a moistening device to permit it to operate on wet-bulb tem peratures. Such an instrument can be used to control the wet-bulb depression and thus the relative humidity. 4. A humidistat which responds directly to changes in humidity may be used to maintain a predetermined relative humidity with constant or with varying temperature. It may do this by varying the dew-point temperature of air leaving a conditioner; by varying, with dampers, the proportion of moist and dry air; by varying the amount of moisture otherwise added to the air; or by varying the dry-bulb temperature. CENTRAL FAN AIR CONDITIONING SYSTEMS In central fan air conditioning systems as described in Chapters 9 and 22, varying amounts of outside and recirculated air are used, except where contamination prevents re-use, and in general for obtaining humidity Fig. 11. All-Seasons Air Conditioning System with Complete Automatic Controls control under winter conditions heat is supplied to the air after it has passed the cooling coils. There are many control variations in use, and it is impractical to attempt a description of all the more usual ones in the limited space available. The following described system is, however, representative of many which are now in use. Fig. 11 is a diagrammatic view of a completely automatic control system for heating and cooling, humidifying and dehumidifying. No manual switching is required between summer and winter operations. The control is fully automatic even in the spring and fall and under conditions where cooling and dehumidification is required in relatively cold weather. Description of Control Units , Thermostat 1 controls damper 2 so that as the temperature at the thermostat rises above its setting, more outside air and less recirculating air is used. Relay 3 in the fan motor circuit is so arranged that when the 283 of andAmerican Society Heating Ventilating Engineers Guide, 1936 motor is stopped, the outside air damper is completely closed. Ther mostat 4 in the incoming air is connected to controller 2 in such a manner that, regardless of thermostat 1, when the outside air is above the setting of this thermostat, the outside air damper will be closed to whatever minimum is set by the requirements of a code or the particular use of the system. Thermostat 5 is located at approximately the same point as 1, but controls valve 6 on the preheater so that if the temperature at thermostat 5 falls below its setting (which should be lower than the setting of .thermostat 1), the recirculated air will be reheated so that the mixture will rise above this setting. Both controller 2 and valve 6 should be modulating type. The preheater may be placed in the outside air instead of in the recirculated air, but if this is done an additional ther mostat will ordinarily be required in the outside air in order to prevent the possibility of freezing the preheater. Room thermostat 7 governs con troller 8, which operates a face and by-pass damper as shown, and valve 9 on the reheater coil. The connection is such that if the room temperature is below the setting of thermostat 7, the by-pass damper will be closed and the face damper opened and, if necessary, more steam admitted to the reheater coil. Duct thermostat 10 inserted in the fan discharge is con nected with thermostat 7 so that if the fan discharge temperature falls below the setting of thermostat 10, controller 8 and valve 9 will be moved in the direction to deliver more heat. Both controller 8 and valve 9 should be modulating type. Room thermostat 11 and duct thermostat 12 together control the cooling equipment which is shown as a relay to start the compressor. These thermostats must be respectively set for higher temperatures than thermostats 7 and 10. They are arranged so that if the temperature of the room exceeds the setting of thermostat 11, the cooling will be initiated unless the temperature of the fan discharge is below the setting of?tl||prnostat 12. Hygrostat 14 is also arranged to control relay 16 but imsuch a manner that if the relative humidity is above the setting of hygrostat 14, the cooling will be initiated regardless of the temperature in the fan, discharge. In this case, the fan discharge temperature will be controlled by thermostat 10. Hygrostat 15, set much lower than hygrostat 14, is shown controlling a valve 13 for a spray type, humidifier. , Heating Season Operation Temperatures indicated in Fig.'ll will be used in the following descrip tion of operation as they are fairly indicative of an average installation of this type. The temperature at thermostats 1 and 5 will be maintained at 60, F if the weather is not too severe (below about 15 F if a minimum of 25 per cent outside air. is required) by movement of the outside air and recirculated air dampers through the medium of controller 2. If the weather is extremely cold, the temperature at this point will be main tained at 55 F by means of thermostat 5. If the room temperature is below 72 F (the setting of thermostat 7), controller 8 and valve 9 will move in the direction to increase the'heat until thermostat 7 is satisfied, after which they will move in the direction to decrease the heat until the duct temperature falls to 60 F. Hygrostat 15 will Introduce moistiire if the relative humidity in the room falls below 30 per cent. Even in rather cold weather cooling is sometimes required, but will be 284 Chapter 14--Temperature and Humidity Control supplied without artificial refrigeration since the thermostat 7 will be above its setting and the fan discharge will be held at 60 F. The starting of the compressor will be prevented by thermostat 12 even if the room temperature goes above 75 F. Cooling Season Operation If the weather is very warm, thermostat 4 will close the outside air damper to its minimum position, and thermostat 1 will no longer be in control. If the compressor is stopped, the temperature at thermostat 12 will exceed 62 F which will cause the compressor to start provided the room temperature is above 75 F (the setting of thermostat 11). However, if the relative humidity exceeds 55 per cent, the temperature of the air leaving the cooling coils should be reduced as much as possible, and under this condition hygrostat 14 (as previously described) causes the com pressor to run continuously. If sufficient cooling capacity is provided, the temperature leaving the cooling coils will fall below 60 F (the setting of thermostat 10) which will cause controller 8 and valve 9 to reheat the air to 60 F, thus providing maximum dehumidification and a satisfactory entering air temperature. If cooling is required in mild weather (for example, 55 F outside), the control functions as before except that thermostat 1 is in control of the outside air and recirculated air damper, and sufficient cooling and dehu. midification may be provided by the outside air alone. However,. if '^..insufficient cooling or insufficient dehumidification (or both) can be obtained in this manner, the fan discharge temperature will exceed 62 F with the room thermostat 11 above its setting, or the relative humidity will exceed the setting of hygrostat 14, and the artificial refrigerating system will again come into operation. PROBLEMS IN PRACTICE 1 What important functions of heating, ventilating, and air conditioning systems do automatic controls fulfill? . . Controls are applied to maintain adequate requirements for human confort and efficiency; to maintain requirements for industrial processes; to obtain economy in operation; and to provide necessary safety measures. 2 How may temperature control be obtained in a room heated by a unit heater? . With constant steam supply, the unit heater motor may be started or stopped by a thermostat, either directly or through a relay. With intermittent steam supply, opera tion of the motor by thermostat can be limited to the time that steam is available, by using a reverse-acting temperature or pressure limit switch. 3 How may temperature control be provided in a room heated and venti lated by a unit ventilator which includes two extended-surface units? Operation of the unit for service during occupancy of the room may be manual, by switch, or by time clock. When the desired temperature level is reached, the outside air intake may be controlled by a damper motor coupled with the fan motor circuit by means of a thermostat. The outside air damper will operate to a given position in _J> either case. -. ?. -4>r passing through the unit may be preheated through the first heating coil to a definite temperature by a control valve on the steam supply governed by a temperature controller reacting to the temperature of the air on the outlet side of the convector. The second 285 . of andAmerican Society Heating Ventilating Engineers Guide, 1936 heating coil may provide the necessary heating capacity, and the steam supply to this coil may be modulated, either manually or automatically, in accordance with the tem perature required in the room. 4 How may temperature control be obtained in a room heated by a duct system? Air may enter the room from the central fan system at a predetermined minimum tem perature. Heaters placed in the duct to bring the air up to this temperature should be equipped with face and by-pass dampers which may be adjusted by a positioning damper motor to give temperature control. . 5 How may temperature control be obtained in a room cooled by a selfcontained mechanical unit? The fan operation may be controlled by a manual switch, while a room thermostat in con junction with a solenoid valve may regulate the flow of the refrigerant to the coil. The thermostatic circuit might be operative only when the fans are running; and the com pressor might be controlled by refrigerant pressure. 6 How may temperature control be obtained in a room heated by aq auto matically-fired warm air furnace? A room thermostat might control the combustion unit; and a limit switch in the top of the furnace unit, when at a low setting of its control might operate the fan whenever there is a rise of temperature, and when at a high setting of its control it might shut off the combustion unit. A room humidity control operating a solenoid valve on the water supply to the humidifier, or operating a relay on the recirculating pump motor to the humidifier, may be connected in parallel with the fan motor. Humidification may be supplied only when heat is supplied and when the humidity control acts in conjunction with a time switch. 7 How may humidity be controlled in a unit humidifier for a steam or hot water heating plant? Since heat is required for evaporation, a temperature limit switch, preferably of the immersion type, may be placed in the heating supply riser to cause the unit to be in operative when heat is not available. A room humidity control will operate a solenoid valve on the water supply to the sprays. Both the solenoid valve and the humidity control may be electrically wired in parallel with a fan motor, and be subject to the temperature limit switch. 8 Discuss a control system, including control of humidity, for the heating cycle of a central fan system of air conditioning. During theheating cycle it is necessary to vary the amount of outdoor air drawn into.the system in accordance with the temperature of that air. It is also advisable to adjust the volume of return air when mixing it with the outdoor air so that the resultant mixture will be of constant volume delivered to the preheater coils at some predetermined con stant temperature. . ' The reheating coil determines the dry-bulb temperature of the delivered air, so if the conditioner is equipped with both face and by-pass'dampers on this coil it is obvious that these dampers should be controlled by a thermostat located at some representative position in the space being supplied with the conditioned air. If this thermostat is in turn connected with auxiliary apparatus which will vary the damper settings, it will be possible to pass more or less air through the reheater as the temperature falls or rises. A low-limit temperature control might also be mounted in the discharge duct as a precaution against blowing cold air into the space. Such control would actuate the dampers of the reheater when the duct temperature fell below a predetermined minimum regardless of the demands of the master controller. ' The amount of steam supplied to the reheater coils should be a function of the position of the dampers. If the face dampers are closed no heat is required, and to conserve steam suitable interconnection between the damper motor and the control valve should be made in order that this valve will close whenever the damper valve is closed. By adding modulating auxiliary apparatus to the steam valve, it may be made to operate proportionately to the setting of the dampers. ^ - 286 Chapter 15 AIR POLLUTION Sources of Air Pollution, Effects of Air Pollution on Health, Pul monary Effects, Occlusion of Solar Radiation, Industrial Air Pollution, Abatement of Atmospheric Pollution, Smoke Abate- ment. Dust and Cinder Abatement . THIS chapter considers the hygienic aspects of atmospheric pollution and the methods by which this pollution may be lessened. Infor mation concerning the cleaning of air brought into buildings for ventilat ing purposes will be found in Chapter 16, and a discussion of the exhaust ing of dusts and toxic gases from factories and industrial plants is con sidered in Chapter 21. . The impurities which contribute to atmospheric pollution include carbon from the combustion of fuels, particles of earth, sand, ash, rubber tires, leather, animal excretion, stone, wood, rust, paper, threads, of cotton, wool, and silk, bits of animal and vegetable matter, and pollen. Microscopic examination of the impurities in city air shows that a large percentage of the particles are carbon. (See Fig. 1, Chapter 16, for size . of impurities in air.) Dust, Fumes, Smoke . The most conspicuous sources of atmospheric pollution may be arbitrarily classified according to the size of the particles as dusts, fumes, and smoke. Dusts are particles of solid matter varying from 1.0 to 150 microns in size. Fumes include particles resulting from chemical pro cessing, combustion, explosion, and distillation, ranging from 0.1 to 1.0 . micron in size. Smoke is composed of fine soot or carbon particles, less than 0.1 micron in size, which result from incomplete combustion of carbonaceous materials, such as coal, oil, tar, and tobacco. In addition to carbon and soot, smoke contains unconsumed hydrocarbon gases, sulphur dioxide, sulphuric acid, carbon monoxide, and other industrial gases capable of injuring property, vegetation, and health. The lines of demarcation in these three classifications are neither sharp nor positive, but the distinction is descriptive of the naiture and origin of the particles, and their physical action. Dusts settle without appreciable agglomeration, fumes tend, to aggregate, smoke to diffuse. Particles larger than one micron will eventually settle out by gravitation; particles smaller will remain in suspension as permanent impurities unless they agglomerate to sizes larger than one micron; .. 287 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Fly-Ash, Cinders The term fly-ash is usually applied to the extremely small particles of ash, and the term cinder to the larger particles of coke and ash which are discharged with the gases of combustion from burning coal. AIR POLLUTION AND HEALTH Many kinds of dusts and gases are capable of producing pathological changes which may cause ill health. The harmful effects depend largely upon the chemical and physical nature of the impurities, and the con centration, length of time, and conditions under which they are breathed. Dust particles must be minute in size to be inhaled at all, although fairly large particles may gain access to the upper air passages. The human body possesses remarkable filtering media for protecting the lungs. Small hairs which line the nasal passages, and a multitude of microscopic hairs, called cilia, in the epithelial lining in the bronchial tubes intercept many of the dust particles before they reach the lungs. The constant inhalation of dusts in city air irritates the mucous mem branes of the nose, throat, and lungs, and eventually may produce dis'comfort and a series of minor respiratory disorders. The pigmented lung of the city dweller is an example of the pathological change produced over a period of years. This condition may be of no clinical importance, but an exaggeration of it in the coal miner results in anthracosis or dark spots on the lung due to the presence of pigment in the lymph channels which impairs the functioning of the lung cells under stress. Effects of. Solids Bronchitis is the chief condition associated with exposure to thick dust, and follows upon inhalation of practically any kind of insoluble and non- colloidal dust. Atmospheric dust in itself cannot be blamed for. causing tuberculosis, but it appears to have a marked influence in aggravating the disease once it has started. There is, however, quite reliable evidence that carbon pigment, one of the atmospheric dusts, tends to wall off local, tuberculosis rather than to further its spread. ' The sulphurous fumes and tarry matter in smoke are. probably more dangerous than the carbon. In foggy weather the accumulation of these substances in the lower strata may be such as to cause irritation'of the eyes, nose, and respiratory passages, leading to; asthmatic breathing and bronchitis and, in extreme cases, to death. The Meuse Valley fog . disaster will probably become- a classic example in the history of, gaseous air pollution. Released in a rare combination of atmospheric calm- and dense fog, it is believed that sulphur dioxide and other toxic gases from the industrial region of the valley caused 63 sudden deaths, and injuries to several hundred persons. Physical examination showed difficult breathing,-rapid pulse, cyanosis, cardiac dilation, and a redness and inflammation of the mucosa of the nose, jnouth, throat,-trachea, and bronchi. . '. . Carbon monoxide from automobiles and from chimney gases con-' stitutes another important source of aerial pollution in busy cities. During heavy traffic hours and under atmospheric conditions favorable to concentration, the air of congested streets is found to contain enough CO 288 Chapter 15--Air Pollution to menace the health of those exposed over a period of several hours, particularly if their activities call for deep and rapid breathing. In open air under ordinary conditions the concentration of CO in city air is believed to be insufficient to affect the average city dweller or pedestrian. Occlusion of Solar Radiation The loss of light, particularly the occlusion of solar ultra-violet light due to smoke and soot, is beginning to be recognized as a health problem in many industrial cities. Measurements of solar radiation in Baltimore1 by actinic methods show that the ultra-violet light in the country was 50 per cent greater than in the city. In New York City2 a loss as great as 50 per cent in visible light was found by the photo-electric cell method. The effect of air pollution on the health of city dwellers is difficult to determine, owing to the slowness of its manifestations. The aesthetic and economic objections to air pollution are so definite, and the effect of air borne pollen can be shown so readily as the cause of hay fever and other allergic diseases, that means and expenses of prevention or elimination of this pollution have seemed justifiable to the public. AIR POLLUTION IN INDUSTRY In many industrial processes, sufficient amounts of dusts, fumes, and vapors are liberated to be injurious to the health of workers. Some dusts '\are poisonous (lead, mercury, arsenic, manganese, and cadmium) and some act as irritants (silica, steel, iron, and granite). Certain dusts may produce catarrhal conditions and increase susceptibility to such diseases as bronchitis, pneumonia, arid tuberculosis. Silicious dust is especially . harmful because it has a direct damaging action upon the tissue of the lungs, but organic dusts, both animal and vegetable (hair, pollen, textile, and fiber), do not seem to affect the lungs at all, although they may cause considerable discomfort in the upper respiratory passages to persons sensitive to them. Industrial gases and fumes act specifically upon the mucous mem branes, the lungs, blood, skin, and eyes. Some extremely poisonous gases act after very short exposures. Among these are carbon monoxide, hydrogen sulphide, ammonia, chlorine, bromine, arsine, and cyanogen. The industrial processes which liberate harmful substances are too - manifold and the effects too diverse to be considered here, where dis cussion is limited to the commonest and most serious with which the ventilating engineer may be confronted, namely, carbon monoxide, lead, and silica. For a more thorough treatise on the subject reference should be made to books by Hamilton3, Rosenau4, and Henderson and Haggard6. Carbon Monoxide Poisoning . Carbon monoxide is a common form of poisonous industrial gas, met with in mines, foundries, coke-oven sheds, garages, and houses. Its action ^Effects of Atmospheric Pollution upon Incidence of Solar Ultra-Violet Light; by J. H. Shrader. M. H. Coblentz and F. A. Korff (A merican Journal of Public Health, p. 7, Vol. 19. 1929). Studies in Illumination, by J. E. Ives (U. S. Public Health Service Bulletin No. 197, 1930). Industrial Poisons in-the United States, by Alice Hamilton. ' ' Preventive Medicine and Hygiene, by Milton J. Rosenau. f ,, ^'X10U3 Gases, by V. Henderson and H. Haggard. 289 ' American Society of Heating and Ventilating Engineers Guide, 1936 is due to the fact that the combining power of carbon monoxide with the haemoglobin of the red blood corpuscles is about 300 times greater than that of oxygen. Since the resulting stable combination destroys the power of the haemoglobin to unite with oxygen in the lungs and to supply it to the tissues, the effects are due to lack of oxygen, and the symptoms are those of anoxemia, namely, dizziness, headaches, sleepiness, fatigue, and, in extreme cases, paralysis and death. The dangerous saturation level of the blood with carbon monoxide is about 50 per cent. Even as little as 0'.07 per cent in the air will render, in half an hour, one quarter of the red corpuscles incapable of uniting with oxygen. One to two parts per 10,000 parts of air is set as a safe limit of pollution which may be breathed for a long time without producing perceptible symptoms. . Silicosis Silicosis is a chronic disease of the lungs which results from the local physio-chemical action of hydrated silica upon the pulmonary tissue, causing progressive lymphatic fibrosis, and rendering the tissue suscep tible to tuberculosis. The disease is slow in evolution, requiring usually a number of years of exposure. It occurs principally among granite workers, sand blasters, metal miners, metal polishers, potters, and mill stone workers. Lead Poisoning Lead poisoning is the most insidious and most common of all industrial diseases. It occurs principally among lead workers and smelters, lead miners, potters, painters, typesetters, st;ereotypers, plumbers, and workers with glass, gold and silver. Lead, in practically all forms, is a cumulative poison which is absorbed by way of the blood stream, chiefly from the respiratory tract, but also from the digestive tract and from the skin. The effect may be either an acute or chronic poisoning. The principal symptoms are colic, constipation, anemia, headache, anorexia, a bluish line along the edges of the gums, rheumatic pains, and, in extreme conditions, paralysis, blindness, insanity, and death. It has been found6 that 2 mg per day is the smallest dose, by inhalation, which in the course of years may result in lead poisoning. Regular inhalation during the usual working hours of air containing less than 0.2 mg of lead per cubic meter does not seem to produce serious lead poisoning in individuals of representative industrial groups7. \` Prevention ' The prevention of industrial hazards from dusts and. poisonous gases is largely a ventilation problem consisting of keeping the impurities in air down to a safe concentration- As yet there are no generally accepted standards on which to base the design of the ventilation equipment. Approximate data on the toxicity of various gases and fumes met with in industrial establishments are given in Table 1. Column 5, giving the maximum allowable concentrations for prolonged exposures, was com piled from experiments in which most exposures lasted not more than a Lead Poisoning, by Thomas Morrison Legge (Journal Royal Society Arts, 1929, Vol. 77, p. 1023). What is a Dangerous Quantity of Lead Dust in Air, by C. M. Sails (Industrial Hygiene Bulletin, New York State Department of Labor, 1925). 290 15Chapter --Air Pollution week, and it is reasonable to assume that over more prolonged exposures such concentrations would cause pernicious effects. ' Much is known concerning the physiological and pathological effects induced by various types and concentrations of atmospheric pollutants. In the absence of an accepted standard for safe breathing, and because of the slow, cumulative effects of certain kinds of air contaminants, the best procedure is the periodic medical examination of individuals, and the Table 1. Toxicity of Gases and Fumes in Parts per 10,000 Parts of Air* Vapor ob Gab Rapidly Fatal Maximum Concentration POB PROM M to Hour Maximum Concentration por 1 Hour Maximum Allowable fob Prolonged Exposure Carbon monoxide................ Hydrocyanic acid................. Ammonia----- ----------------------- Hydrochloric acid gas.------ Chlorine....................... .......... Hydrofluoric acid gas. .-- Sulphur dioxide.----------------- Hydrogen sulphide-........... Carbon bisulphide.________ Phosphene........... ................. Arsine.. ............... .............. Phosgene.___ .................. Nitrous fumes.. ---------------- Benzene____________________ Toluene and xylene.---------- 40 800-1000 30 50-100 10-20 10 2 4-5 10-30 20 m Over M 2K-7H 190 190 Nitrobenzene._________ ____ Carbon tetrachloride-....... Chloroform._____ Tetrachlorethane Trichlorethylene____ Methyl chloride Methyl bromide_____ _ ,, Lead vapor.___ :____________ 243 480 250 73 370 1500-3000 200-400 15-20 m 25 M a & 5-7 11 4-6 M M 1-iM ...... - 100-220 240 140 .... 200-400 20-40 -- 10 M 3 ___ 2-3 5 1-2 M . 31-47 31-47 1-iM Koo - 40 50 70 10 -- i M l Mo Moo M3 Mo l M Moo Mo Moo 16 2 1M 5-10 2 5-6 Original data compiled by Y. Henderson and H. Haggard. (See Noxious Cases, 1927.) Data revised by T. M. Legge. (See Lessons Learned from Industrial Gases and Fumes, Institute of Chemistry of Great Britain and Ireland, London, 1930.) ' routine measurement and study of the concentration and the physical and chemical characteristics of the dusts to which those individuals are exposed. ABATEMENT OF SMOKE AND AIR POLLUTION Successful abatement of atmospheric pollution requires the combined efforts of the combustion engineer, the public health officer, and the public itself. The complete electrification of industry and railroads, and the separation of industrial and residential communities would aid materially in the effective solution of the problem. In the large cities where the nuisance from smoke, dust and cinders is 291 of and 1936American Society Heating Ventilating Engineers Guide, the most serious, limited areas obtain some relief by the. use of district heating. The boilers in these plants are of large size designed and oper ated to bum the fuel without smoke, and some of them are equipped with dust catching devices. The gases of combustion are usually discharged at a much higher level than is possible in the case of buildings that operate their own boiler plants. . . 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. Especial care must be taken in hand-firing bituminous coals. (See Chapter 27.) 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 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 furnace, supply more air for combustion, and are sometimes effective in reducing the smoke emitted, but care should be taken that holes are not formed in the fire. A lower volatile coal or a higher gravity 'oil always produces less smoke than a high volatile coal or low gravity oil used in the same furnace and fired in the same manner. The installation of more modern or better designed fuel burning equip ment, or a change in the construction of the furnace, will often reduce smoke. The installation of a Dutch oven which will increase the furnace volume and raise the furnace temperature often produces satisfactory results. In the case of new installations, the problem of. smoke abatement cari be solved by the selection of the prope? 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 necessary. Legislative measures at the present time are largely concerned with the smoke discharged from the chimneys of boiler plants. Practically all of the ordinances limit the number of minutes in any one hour that smoke of a specified density, as measured by comparison with a Ringelmann Chart (Chapter 43), may be discharged. . These ordinances do not cover the smoke discharged at low levels by automobiles, and, although they have been instrumental in reducing the 15--Chapter Air Pollution smoke emitted by boiler plants, they have, in many instances, increased the output of chimney dust and cinders due to the use of more excess air and to greater turbulence in the furnaces. Legislative measures in general have not as yet covered the noxious gases, such as sulphur dioxide and sulphuric acid mist, which are dis charged with the gases of combustion. Where high sulphur coals are burned, these sulphur gases present a serious problem. DUST AND CINDERS The impurities in the air other than smoke come from so many sources that they are difficult to control. Only those which are produced in large quantities at a comparatively few points, such as the dust, cinders and fly-ash discharged to the atmosphere along with the gases of com bustion from burning solid fuel, can be readily controlled. Dusts and cinders in flue gas may be caught by various devices on the market, such as fabric filters, dust traps, settling chambers, centrifugal separators, electrical precipitators, and gas scrubbers, described in later paragraphs. The cinder particles are usually larger in size than the dust particles; they are gray or black in color, and are abrasive. Being of a larger size, the range within which they may annoy is limited. The dust particles are usually extremely fine; they are light gray or yellow in color, and are not as abrasive as cinder particles. Being ex tremely fine, they are readily distributed over a large area by air currents. The nuisance created by the solid particles in the air is dependent on the size and physical characteristics of the individual particles. The difficulty of catching the dust and cinder particles is principally a function of the size and specific gravity of the particles. 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 coal when they are burned on a grate. Modern 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 pollution of the atmosphere is to be prevented, some type of catcher must be installed. .. Dust and Cinder Catchers8 The various types of dust and cinder catchers available today can be divided into six general classes: 1. Settling chambers. . 2. Dust and cinder traps. 3. Centrifugal separators. . . `. . . See Smoke and Dust Abatement, by M. D. Engle (A.S.H.V.E. Transactions, Vot 37, 1931). 293 1 American Society of Heating and Ventilating Engineers Guide, 1936 4. Electrostatic precipitators. 5. Gas scrubbers. 6. Fabric filters. The selection of the proper type of catcher calls for a careful study of the material to be caught and the draft and space available. After installation, constant vigilance is necessary to keep the catchers in proper working condition if satisfactory operation is to be obtained. If possible, the dust or cinder catcher should be installed on the inlet side of the induced draft fans because the dust and cinders in the gases seriously erode the wheels of the fans, the inlet connections and the scrolls. Where the induced draft fans operate at high tip speeds and no catchers are installed, it is not uncommon for the fans to require major repairs within one year and complete replacement within five years. Settling Chambers Probably the oldest form of dust catcher is the settling chamber, which generally consists of a large-sized, gas-tight space into which the dust-laden gases are discharged before being delivered to the chimney. The velocity of the gas should be reduced to a point where the larger and heavier particles will be precipitated by gravity. For good operation, the velocity of the gas should be reduced to a maximum of 2 fps. The bottoms of the chambers should be provided with dump plates through which the collected dust can be removed. Because these chambers are not effective in removing the finer dust particles they have been practically superseded by smaller and less costly devices. Traps, Catchers, Precipitators Various types of traps have been devised. In general they all depend upon breaking the gas up into thin strata and subjecting those thin strata to several abrupt changes in direction. The dust is thrown out ' of the gas stream into specially shaped pockets, or impinged against a roughened surface. The trapping pockets are drained into a hopper below with a small quantity of gas and the dust settles out by gravity due to the low velocity in the hopper. In the roughened surface type, various sections of the trap are closed off at intervals by means of dampers and the dust is shaken off the roughened surface into a hopper below. These devices work very well in catching large size dust and cinders and trap much of the fine dust. They have been used most extensively on stoker-fired installations. They have the advantages of low pressure drop, relatively small space requirements, and low first cost. Centrifugal catchers obtain separation by projecting the particles tangentially out of the gas stream. The effectiveness of this type of catcher varies directly as the specific weight of the dust and as the square of the tangential velocity, and inversely as the radius of rotation. Electrostatic precipitators are used for catching fine dust. These precipitators consist of dust-tight chambers in which are suspended rein forced concrete slabs on about 10-in. centers. Between the slabs are suspended bare metal rods. High-voltage undirectional current is applied to the reinforcing rods in the concrete slabs acting as positive electrodes, the bare rods acting as negative electrodes. The dust-laden 294 Chapter' 15---Air Pollution gas flows horizontally through the precipitator and the dust particles migrate toward the concrete slabs to which they adhere and then fall or are scraped off into the dust hoppers below. . Gas Scrubbers Wet scrubbers have been used for many years for removing dust from gases. A number of different types of scrubbers are now being built for removing dust from boiler flue gases. One type depends upon saturating the gas and washing the dust out of suspension by a spray of water. For best results with this type, the water should be atomized into as fine a spray as possible. Another type depends upon splitting the gas into thin strata arid subjecting these strata to a number of abrupt changes in direction) throwing the dust against the wet surfaces. The main problem in develop ing a satisfactory wet dust catcher is to find suitable materials of con struction that will resist the corrosive action of the wash water for a reasonable length of time. Fabric Filters . Filters of many kinds have been used with variable success. The filter bags are made of cotton, wool or asbestos fabric. The fabrics used in these filters do not withstand the temperatures at which gases are usually discharged from the boilers, and hence the gases must be cooled by some means. Surface coolers or water sprays can be used for reducing the gas temperatures. . :. One of the serious objections to all of these dust catchers is the relatively high cost of installation and maintenance, and the space required for installation'.- ? ' .. . . Disposal of Dust and Cinders Even after the dust and cinders have been caught, the disposal of the material caught presents a serious problem. The cinders discharged with the gases from stoker-fired boilers are usually very high in crirbon arid contain from 50 to 80 per cent as much heat per pound as the coal which is being burned. It is possible, and usually economical, to burn these cinders. They cannot be satisfactorily mixed with the coal in the stoker hopper but they can be blown into the furnace over the stoker fuel bed and burned satisfactorily. If a sufficient quantity of cinders is caught,' a small unit pulverizer can be installed to prepare them for burning over the stoker fuel bed. The same pulverizer can be used for coal at times cif peak load and will materially increase the capacity of the fuel-burning equipment for the boiler to which it is connected. . No satisfactory market has been developed for the dust caught, frbm pulverized coal installations,. but the possibilities are being investigated and it seems likely that in the future this material will have a market value that will go a long way toward paying the fixed charges on the cost of catching it. - distribution of dust in the gas entering and .leaving the dust and cinder catchers is not uniform and is different iri practically every in- 295 American Society of Heating and Ventilating Engineers Guide, 1936 stallation, and varies. widely with changes in furnace conditions. In order to obtain a representative sample it is necessary to traverse the inlet and outlet of the catcher with a sampling tube which faces into the gas flow. The velocity of the gas into the sampling tube must be the same as the velocity of the gas in the duct at the instant the sample is taken. The swirls and eddy currents in the ducts make it difficult to obtain consistent readings, but if the test is conducted by some one of experience, an indication of the approximate efficiency can be obtained. Nature's Dust Catcher Nature has provided means for catching solid particles in the air and depositing them upon the earth. A dust particle forms the nucleus for each rain drop and the rain picks up dust as it falls from the clouds to the earth. In fact, without dust in the air to form the nuclei for rain drops it would never rain, and the earth would be continually enveloped in a cloud of vapor. PROBLEMS IX PRACTICE 1 0 Classify the detrimental aspects of air pollution as it effects large industrial communities. Air pollution may be classified (a) medical, as it affects the physiological functions of people; (6) botanical, as it affects vegetation, trees, plants, shrubs and flowers; and (c) physical, as it affects the discolorization and deterioration of buildings, and the nuisance of soiled interior furnishings, clothes, merchandise, etc. 2 Distinguish between dusts, fumes, and smokes. Solid particles ranging in size from 1.0 micron to 150 microns are called dusts (micron = 365.000 in-)- Particles resulting from sundry chemical reactions and ranging from 0.1 to 1.0 micron in size are called fumes. Carbon particles less than 0.1 micron in size which generally arise from the incomplete combustion of such materials as coal, oil, or tobacco are called smokes. .3 # What are some of the more important physical properties of these various groups of foreign bodies which are of importance in ventilation? In slowly moving air, dusts tend to settle out by gravity without agglomerating to form larger particles; fumes have the tendency to form larger particles which will settle when they attain the size of approximately 1.0 micron; while smokes tend to diffuse and remain in the air as permanent impurities. . 4 0 Why is atmospheric pollution an important engineering problem? a. Certain impurities, when present in too great concentrations, cause ill health or even death. . b. High concentrations of solids occlude solar radiations. c. Some materials cause permanent'injury to parts of buildings, as sulphur fumes corrode exposed metal. . . d. Extra cleaning expense is incurred in dusty localities. e. Internal combustion engines are damaged by abrasive dusts.5 5 How may the hazards of dust-producing industrial operations best be curtailed? '. By providing mechanical exhaust ventilation sufficient to keep dust concentration at a safe level (see Table 1) and then removing foreign bodies to reduce the pollution of out side air. 296 Chapter 15--Air Pollution g 0 How may the pollution of the atmosphere be lessened? . By compelling industrial plants to install dust catching and smoke controlling devices. In many cities the domestic heating plant is one of the most serious offenders, but these plants are too small to justify the installation of dust catchers. Public education in improved firing methods would be of considerable help in this field. 7 Compare the dry and wet types of dust catchers. The dry types are very effective in removing the larger dust particles but the smaller particles generally pass through other kinds than the electric precipitator. The dry types also require considerable space and therefore sometimes introduce resistance to the flow of air. The wet types are effective in removing some of the smaller dusts and the water-soluble gases. The principal disadvantage of the washer is its short life caused by the corrosive action of the wash water. 8 What size particles are detrimental to health? While fairly large particles may enter the upper air passages, those found in the lungs are seldom more than 10 microns in size, and comparatively few of them are more than 5 microns. It is agreed that particles between 36 and 2 microns may be harmful; some authorities place the upper limit at about 5 microns, and some incline to extend the lower limit to 0.1 of a micron. 9 Is the shape of the particle of any significance? Hard particles with sharp corners or edges have a-cutting effect on the delicate mucous membranes of the upper respiratory tract which may lower the resistance of the nose and throat to acute infections. This is aggravated by the irritating effects of some chemical compounds which may be taken in with the air and which act to reduce resistance. 10 0 What are the principal meteorological effects of smoke and dust? a. The reduction in the amount of light received. Measurements have shown that visible light may be as much as 50 per cent less intense in a smoky section of a city than in a section that is free from smoke. Ultra-violet light is reduced as much or more, and in some cases is cut out entirely for a time. b. Smoke and dust aid in the formation and prolongation of fogs. City fogs accumulate smoke and become darker in color and very objectionable. The sun requires a longer time to disperse them, and when the water is evaporated, there is a rain of smoke and soot particles that have been entrained. 11 0 Why has not smoke abatement been more effective? Because communities have not been made sufficiently aware of the possibilities of burning high volatile fuels smokelessly and of separating cinder and ash from the stack gases to a degree that will prevent a nuisance. 12 0 Is the abatement of dust and cinders important? Yes. Only a small percentage of the solid emission from stacks is smoke, in the accepted popular sense; the remainder is fly-ash and cinders. While black smoke is disagreeable and its tarry matter and carbon particles soil anything with which they come in contact, the cinders and some of the ash are hard and destructive. They also, together with dusts from industrial processes, make up the hard, sharp, irritating,, air-borne solids that are breathed by individuals not working in a dusty mill or factory. 13 0 Are air-borne impurities causative factors in hay fever, bronchial asthma, and allergic disorders? Yes. Recent medical investigations indicate that 90 per cent of seasonal hay fever and 40 per cent of bronchial asthma are caused by air-borne pollens, tree dusts, and other allergic irritants. 14 0 Name some essential requirements for the smokeless combustion of fuels. Time, temperature, and turbulence. A study of these factors is usually of value in overcoming a smoke nuisance. of and 1936American Society Heating Ventilating Engineers Guide, 15 "What is the Ringelmann Chart Method of comparing smoke densities? See Chapter 43. The Ringelmann Chart consists of four cards ruled with lines having different degrees of blackness. These cards, together with a white card and a black one,are hung in a horizontal row 50 ft from the observer. At this distance the lines become invisible and the cards appear to be different shades of gray, ranging from white to black. The observer, by matching the cards against the shades of smoke coming from a stack, is able to estimate the blackness of the smoke as compared with the chart. Chapter 16 AIR CLEANING DEVICES Requirements of an Air Cleaner, Types, Air Washers and Scrubbers, Viscous Type Filters, Dry Air Filters, Air Filter Installations THE removal of impurities from air brought into a building forventilating or air conditioning purposes is the function of any air cleaning or filtering device. These impurities include carbon (soot) from the incomplete combustion of fuels burned, in furnaces and automobile engines, particles of earth, sand, ash, automobile tires, leather, animal excretion, stone, wood, rust and paper, threads of cotton, wool and silk, bits of animal and vegetable matter, bacteria and pollen. Microscopic examination shows that the character of the impurities varies with the locality, but as a rule carbon forms the greater part of them while the total is somewhat proportional to. the state of industrial activity and the wind intensity. Additional information on sources of air pollution will be found in Chapter 15. . Observations have shown that practically all atmospheric impurities are less than 5 microns in size. (One micron equals 0.001 millimeter or approximately 0.00004 in.) The size and composition of each individual particle determines its buoyancy and consequently the length of time it will remain in suspension. The chart, Fig. 1, shows graphically the sizes of impurities found in the air, and other related data. To estimate the probable dust load for air filter installations, the following approximate averages of atmospheric dust concentration may be used (7000 grains equal 1 lb): Rural and suburban districts............................................ 0.2to0.4grainsper1000cuft Metropolitan districts.................................................. .0.4to0.8grainsper1000cuft Industrial districts.............................................................................. 0.8 to 1.5 grains per 1000 cuft REQUIREMENTS OF AN AIR CLEANER To fulfill the essential requirements of clean air, an air cleaner should: 1. Be efficient in the removal of harmful and objectionable impurities in the air, such as dust, dirt, pollens, bacteria. . 2. Be efficient over a considerable range of air velocities. 3. Have a low frictional resistance to air flow; that is, the pressure drop across the filter, measured in inches of water, should be as low as possible. 4. Have a large dust-holding capacity without excessive increase of resistance, or have ability to operate so as to keep the resistance constant automatically. ' 5. Be easy to clean and handle, or clean itself automatically. ' 6. Leave the air passing through the cleaner free from entrained moisture or charging liquids used in the cleaner. . 299 American Society of Heating and Ventilating Engineers Gums, 1936 The A.S.H.V.E. Standard Code for Testing and Rating Air Cleaning Devices Used in General Ventilating Work1 explains how such devices are rated by (1) capacity in cubic feet of air handled per minute, (2) resistance in inches of water at rated capacity, (3) dust arrestance, the percentage relationship expressing dust removal efficiency at rated capacity, (4) reconditioning power, the energy necessary to operate the mechanism of Adopted 1934 by A.S.H.V.E. See Chapter 44. Chapter 16--Air Cleaning Devices an automatic air cleaning device, and (5) dust holding capacity,: the amount by weight of standard dust which a non-automatic air cleaning device will retain before reconditioning is necessary; TYPES OF AIR CLEANERS According to the Code, the following four classifications are given the devices: Class A. Automatic Type: In general all air cleaning devices which use power to automatically recondition the filter medium and maintain a non-varying resistance to air flow. . ... Class B. Low Resistance Non-Automatic Type: Air cleaning devices for warm air furnaces unit ventilating machines and similar apparatus and installations in which a maximum of not more than 0.18 in. water gage is available to move air through the air cleaning device. Class C. Medium Resistance Non-Automatic Type: Air cleaning devices for systems in which a maximum of not more than 0.5 in. water gage is available to move air through the air cleaning device. Class D. High Resistance Non-Automatic Type: Air cleaning devices for the air intake of compressors, internal combustion engines, and the like, where a pressure of 1.0 in. or more water gage is available to move air through the air cleaning device. Air cleaners may be also classified as follows: 1. According to principle of air cleaning. a. Air washers. b. Viscous air filters. (1) Unit type. (2) Automatic type. c. Dry air filters. ' 2. According to application. a. For central fan systems of ventilation and air conditioning. Filters of the automatic or semi-automatic type are usually recommended and are installed in a central plenum chamber. b. For unit ventilators. Filters of viscous unit or dry type, installed at inlet of individual units. c. For window installations. Self-contained units consisting of fan and filter, usually dry type, adapted to be placed in the ordinary window. d. For Warm-air furnaces. Unit type viscous or dry filters placed in small plenum chamber of warm-air house heating systems. . e. For compressors and Diesel engines. Unit type viscous or dry filters, installed at air intake of compressors and Diesel engines. . f. For compressed air lines. Unit type viscous or dry filters. With the growing congestion of large cities and an industrial growth" throughout the entire country, the percentages of foreign material in the air, such as soot or carbon, which are unaffected by an air washer type of .air cleaner, have increased. This has brought about the development of the viscous and dry type air filters which are part of many ventilating and air conditioning systems. AIR WASHERS AND SCRUBBERS Information on air washers will be found in Chapter 11. Scrubbers have not been used very extensively in the past for cleaning American Society of Heating and Ventilating Engineers Guide, 1936 air for ventilating purposes. However, new types have been developed which appear to have possibilities for cases where the air to be cleaned is extremely dirty or where a higher degree of cleanliness is desired than can be obtained with an air washer. VISCOUS TYPE FILTERS The principle of air cleaning used in viscous filters is that of adhesive impingement. Dust and dirt in the air, especially soot and carbons, are trapped and retained by successive impingements on coated surfaces. While the arrangements of filtering media and the kind of materials used are almost unlimited, there are certain rather definite requirements for a practical commercial filter. Investigations in this country and abroad demonstrate that the first impingement of dust laden air on a viscous coated surface removes about 60 per cent of the dust, the next impingement takes 60 per cent of what then remains--that is, 24 per cent--and the next impingement removes 9.6 per cent. To secure maximum efficiency, it is necessary to divide the air into innumerable fine streams, as the more intimately and freely the air is brought into contact with the viscous-coated media the better will be the cleaning. The binding liquid used with viscous filters should have the following properties: 1. Its surface tension should be such as to produce a homogeneous film-like coating on the filter medium. 2. The viscosity should vary only slightly with normal changes of temperature. 3. It should be germicidal in its action to prevent the development of mold spores and bacteria on the filter media. 4. The liquid should flow freely at low temperatures. 5. Evaporation should not exceed 1 per cent. 6. It should be fireproof. 7. It should be odorless. . Viscous Unit Filters In the unit type viscous filter, the filtering media are arranged in units of convenient size to facilitate installation, maintenance, and cleaning. Each unit consists of an interchangeable cell or replaceable filter pad and a substantial frame which may be bolted to the frames of other like units to form a partition between the source df dusty air and the fan inlet. The necessary washing, draining, and recharging equipment should be installed near each group of unit filters, with hot water and sewer con nections provided. ' To secure greater dust holding capacity and a practically constant resistance and air volume, the filter media are usually placed in the direction of air flow, with progressively finer filter densities determined' by the percentage of dust impinged. This arrangement provides relatively large spaces for the collection of dirt in the front'of the filter where the' bulk of the dust is taken out without undue increase in resistance, while at the back of the filter the openings are smaller to secure high efficiency in the removal of the finer dust particles. The resistance of a well-designed unit filter of-the adhesive impinge- - Chapter 16--Air Cleaning Devices ment type usually depends.upon the velocity at which the air is handled and upon whether the unit is clean or dirty. The cleaning efficiency of the unit is usually highest after it has accumulated a certain portion of its maximum load of dirt because some dust collected in the cell acts as an efficient medium for the further seizing of solids from the air. By periodi cally cleaning a predetermined number of cells, the resistance and capacity of a built-up filter may be held at any desired figure. The frequency of cleaning any unit filter installation depends upon the dust concentration Fig. 2. Chart Showing Change in Resistance Due to Dust Accumulation of air being cleaned, and on the amount of dirt which can be accumulated in the filter medium without causing excessive resistance. (Figs. 2,3 and 4.) Filters consisting of inexpensive frames of cardboard or similar material filled with viscous-coated glass wool or steel wool are available. Because of their construction these units may be discarded when dirty and replaced with new units at relatively little expense. They are used in general ventilation work and with warm air furnaces and other installations where first cost and low resistance to air flow are essential. The operating characteristics of these units conform in general with those of the rigid frame type. Viscous Automatic Filters . The principle of air cleaning used in the viscous automatic filters is the same , as in the unit filters. The removal of the accumulated dust, 303 American Society of Heating and Ventilating Engineers Guide, 1936 however, is done automatically instead of by hand. The automatic clean ing and recoating of these filters is based on the principle that the viscous fluid itself will perform the cleaning function, thereby eliminating a sepa rate washing agent. The dust collected by the filter thus is deposited finally in the bottom of the viscous fluid reservoir from which it may be removed by different methods, depending on the design of the filter. There are three general types of automatic filters. They are differentiated from each other according to the process of self-cleaning and renewing of the viscous coating used by each type, as follows: 1. The filter medium has the form of an endless curtain suspended vertically, with its lower portion submerged in'a viscous fluid reservoir. The curtain rotates slowly through this bath, thus performing the cleaning and recoating of the filter medium. 2. The filter screen is arranged m the form of shelves or cylinders, and the viscous fluid is flushed through all parts of the medium in a direction opposite to the air flow. 3. The filter medium is arranged vertically and is stationary. The viscous fluid is flushed from above over the medium, while the air flow is stopped. Fig. .4. Maintenance Chart for Unit Type Viscous Filters . The washing and renewing process in automatic filters usually is inter mittent. It is-accomplished by an electric motor or by other motive power and is controlled by manual or by automatic timing devices. The operating cycle is of a predetermined frequency and should be so timed as to insure a constant static pressure drop across the filter. The customary resistance to air flow is 2'8-in. water gage at an air velocity of 500 fpm, measured at the filter entrance. Automatic viscous filters are made up in units which are delivered either fully assembled or in parts to be assem bled at the point of installation. .` DRY AIR FILTERS Dry air filters, in which dust is impinged upon or filtered through screens made of felt, cloth, or cellulose, are available in various types. These filters require no adhesive liquid, but depend op, the straining or., screening action of the filtering medium. Because of the close texture 304 . . Chapter 16--Air Cleaning Devices of the filtering media used in most of the dry filters, the surface velocity, or velocity of the air entering the media, ranges between 10 and 50 fpm, depending on the nature and texture of the fabric. This necessitates a relatively large screen surface, and the filter media are usually arranged in the form of pockets to bring the frontal area within customary Space requirements. As in viscous unit filters, an average constant resistance and air volume may be obtained by periodic reconditioning or renewal of the filter screens. Since some materials suitable for dry filtering media are affected considerably by moisture which tends to cause a rapid increase in resis tance, they should be treated or processed to minimize the effect of changes in humidity. . Filters using felt and similar materials as filter media depend upon vacuum cleaning for reconditioning. A special nozzle, operated from a portable or stationary vacuum cleaner, is shaped to reach all parts of the filter pockets. Permanent filter media should be capable of withstanding repeated vacuum cleanings without loss in dust removal efficiency. While most dry filters are cleaned by replacing an inexpensive filter sheet, the useful life of these sheets often may be lengthened by vibrating or vacuum cleaning. INSTALLATION METHODS The published performance data for all air filters are based on straight through unrestricted air flow. Filters should be installed so that the face area is at right angles to the air flow whenever possible. Eddy currents and dead air spaces should be avoided and air should be distributed uniformly over the entire filter surface, using baffles or diffusers if neces sary. . : The most important requirements of a satisfactory and efficiently operating air filter installation are: 1. The filter must be of ample size for the amount of air it is expected to handle. An overload of 10 to 15 per cent 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 clean liness 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 expense and convenience of maintenance. . The following recommendations apply to filters and washers installed with central fan systems: 1. Duct connections to and from the filter should change size dr 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 connections leading to and from the filters. ' 4. All doors on the clean air side should be lined with felt to prevent infiltration of unclean air. AH connections and seams of the sheet metal ducts on the clean air side should be as air-tight as possible. ' ' 305 American Society of Heating and Ventilating Engineers Guide, 1936 6. 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 time. 7. Filters installed close to air inlet should be protected from the weather by suit able 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 re sistance reaches too high a value. REFERENCES Testing and Rating of Air Cleaning Devices Used for General Ventilation Work, by Samuel R. Lewis (A.S.H.V.E. Transactions, Vol. 39, 1933). Fundamental Principles in the Design of Dry Air Filters, by Otto Wechsberg (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, April, 1933). Operation and Maintenance of Air Filters, by W. G. Frank (Heating, Piping and Air Conditioning, May, 1931). Size and Characteristics of Air-Borne Impurities, by W. G. Frank (Heating, Piping and Air Conditioning, January, 1932). ' Determining the Quantity of Dust in Air by Impingement, by F. B. Rowley and John Beal (A.S.H.V.E. Transactions, Vol. 35, 1929). A Study of Dust Determinators, by F. B. Rowley and John Beal (A.S.H.V.E. Trans actions, Vol. 34, 1928). Design and Application of Oil-Coated Air Filters, by H. C. Murphy (A.S.Jf.V.E. Transactions, Vol. 33, 1927). Determining the Efficiency of Air Cleaners, by A; M. Goodloe (A.S.H.V.E. Trans actions, Vol. 30, 1924). PROBLEMS IN PRACTICE 1 Assume a fan and duct system which handled 10,000 cfm through clean filters with a system resistance of 0.8 in. of water and that after the filters have become dirty the system resistance increases to 1.0 in. of water, and that the fan speed remains unchanged. Is there any way of predicting the volume of air delivered after the filter becomes dirty? ': Yes. If the performance curves for the particular make of fan are available, the new volume may be determined from the resistance pressure curve. (Figs.- 1, 2, 3 and 4, Chapter 17.) 2 What are the advantages of viscous filters? The principal advantage of the viscous filter is its large dust holding capacity. The dust accumulation is distributed through the depth of the filtering medium rather than upon the surface as in the dry types, which makes it possible for viscous filters to handle heavy dust concentrations without excessive resistance. Since its efficiency and resis tance are based on maximum air velocities of from 300 to 500 fpm through the-filter, the viscous filter consumes the minimum amount of space for a given air volume. 3 What are the advantages of dry filters? , Dry filters are more efficient in the removal of fine .dust particles from the air, and some types will eliminate even as much as 60 per cent of the smoke particles. Dry filters also are easily and conveniently maintained by vacuunl cleaning, vibrating, or renewing the filtering medium. - , 4 If an air washer is used for cooling and humidity control in an air con ditioning system, is a filter needed? , An air filter is desirable in conjunction with an air washer because of the large amount of soot in the air which, due to its greasy and amorphous nature, is not readily trapped in 306 Chapter 16--Air Cleaning Devices an air washer. Filters should be placed between the washer arid the air intake so that all the dirt will be collected at one point to simplify maintenance and to protect all the equipment in the system. 5 Is an air filter needed with an extended surface type heat exchanger? An air filter is essential with an extended surface heat exchanger in order to maintain its efficiency, for without this protection dust particles will adhere to the exposed surfaces, and gradually build up a deposit to the point where the efficiency will be impaired and the resistance increased by restricting the air passage. 6 What is the proper location of a filter in relation to the fan? A filter will operate equally well whether placed ori the suction or discharge side of the fan. It has become standard practice, however, to locate the filter on the fan inlet side because there it has: (1) simpler duct connections, (2) reduced static pressure losses, (3) more even air distribution over the entire filter area. Where an exceptionally high efficiency in dust removal must be maintained, it is often advisable to place the filter on the discharge side of the fan so there can be no infiltration of unclean air. 7 What Instruments and apparatus are required for determining the pollen concentration in air by means of the settling method? A microscope with a field of known area and a glass slide coated with a viscous material. 8 Describe the procedure for determining the pollen concentration in air by means of the settling method. . A glass slide coated with a viscous material is placed for a period of 24 hours in a hori zontal position in the atmosphere to be tested. The slide is then removed and placed under the microscope, and pollen counts are made of approximately 25 fields over the area of the glass slide. Having determined the count over a definite area, as for example, 1 sq cm, and finding the settling rate of the average particles from the chart, Fig. 1, the concentration in parts per cubic yard can be calculated. 9 The resistance to air flow of a unit air filter is found to be 0.4 in. of water. The volume of air passing through the filter is 1000 cfm at a velocity of 200 fpm. What would be the filter area required in order to reduce the pressure drop across the filter from 0.4 in. of water to 0.16 in. of water? Referring to Fig. 3: velocity, or The resistance is substantially proportional to-the square of the V . R, Vj* 0.4 200* 0.16 = 7,* 7* = 16,000 V, = 126.5 fpm Q = AV 1000 = 126.5 A . _1000 , A = 12675 = 7`91 sq ft The filter area would be increased from 5 sq ft to 7.91 sq ft. 10 A ventilating system complete with filters has a fan which, when operating at 400 rpm and delivering air at 1 in. of water total static pressure, requires an input of 3 horsepower. After the system operates for a time, the pressure drop across the filter caused by the clogging action of the collected dust and dirt increases from 0.1 in. of water to 0.4 in. of water. To maintain the original 307 American Society of Heating and Ventilating Engineers Guide, 1936 rate of air delivery with the increased static pressure, at what speed must the fan be run and what horsepower will be required? Static pressure after clogging of filter =? 1 + (0.4 -- 0.1) = 1.3 in. of water. The static pressure varies as the square of the fan speed. Therefore, if X is the fan speed after the static pressure increases: _L15 = \( 4X00 Y) ' X = 456 rpm. The horsepower varies as the cube of the fan speed. Therefore, if V is the horsepower after the static pressure increases: JL - ( 456 Y 3 \ 400 / Y -- 4.44 horsepower. To maintain the original rate of air delivery with the increased static pressure, the fan speed must be increased from 400 to 456 rpm, and the horsepower from 3 to 4.44. Chapter 17 FANS Performance, Fan Efficiency, Characteristic Curves, Selection of Fans, Controls, Designation of Fans IN heating and ventilating practice, fans are used to produce air flow except where positive displacement is required, in which case com pressors or rotary blowers are used. Fans are classified according to the direction of air flow as (1) axial flow or propeller type if the flow is parallel with the axis, and (2) radial flow or centrifugal type if the flow is parallel with the radius of rotation. Axial flow fans are made with various numbers of blades of a variety of forms. The blades may be of uniform thickness (sheet metal), either flat- or cambered, or may be of varying thickness of so-called aerofoil section (airplane propeller type). Where an axial flow fan is intended for operation at comparatively high pressures the hub sometimes is enlarged in the form of a disc and the fan.is known as a disc fan. . Radial flow or centrifugal fans include steel plate fans, pressure blowers, cone fans, and the so-called multiblade fans. All the foregoing types have variations which may be obtained by modification of the proportions orchange in the curvature and angularity of the blades. The angularity of the blades determines the operating characteristics of a fan: a forward curved blade is found in a fan having slow speed operating characteristics, while a backward curved blade is found in a fan having high speed operating characteristics. A wide variation exists in the demands which have to be met by fan installations. A fan may be required to move large quantities of air against little or no resistance or it may be required to move small quanti ties against high resistances. Between these two extremes innumerable specific requirements must be met. In general, fans of all types in each general class can be made to perform the same duty, although mechanical difficulties, noise or lack of efficiency may limit the use to one or another type. The most common field of service for fans of the propeller type is in moving air against moderate resistances, especially where no long ducts or heavy friction must be overcome and where noise is not objectionable, whereas centrifugal fans are commonly employed for operation at the comparatively higher pressures and where extreme quietness is necessary. PERFORMANCE OF FANS Fans of all types follow certain laws of performance which are useful in determining the effect of changes in the conditions of operation. These 309 American Society of Heating and Ventilating Engineers Guide, 1936 laws apply to installations comprising any type of fan, any given piping system and constant air density, and are as follows: 1. The air capacity varies directly as the fan speed. , . 2. The pressure (static, velocity, and total) varies as the square of the fan speed. 3. The power demand varies as the cube of the fan speed. 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? c . Ann ,, 15,000 Speed = 400 X jjjoOO = 500 rpm 500\2 ( J -- 1.56 in. Power = 4 X (^)3 = 7.81hp . -' When the density of the air varies the following laws apply: 4. At constant speed and capacity the pressure and power vary directly as the density. . . Example 2. A certain fan delivers 12,000 cfm at 70 F and normal barometric pressure (density 0.07495 lb per cubic foot) at a static pressure of 1 in. of water when operating at 400 rpm, and requires 4 hp. If the.air temperature is increased to 200 F (density 0.06018 lb) and the speed of the fan remains the same, what will be the static pressure and power? ' . ' So.ta.tic pressure = t1 ^X Q0.0067041985 =,0-.8o0n.in. ' Power = 4 X 0.06018 0.07495 3.20 hp 5. At constant pressure the speed, capacity and power vary inversely as the square root of the density, ' Example 8., If the speed of the fan of Example'2 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? `. Speed = 400 X . . 95 = 446 0.06018 .. Capacity = 12,000 1.07495 = 13,392 cfm (measured at 200 F) ^ 0j.06018 Power = 4 X = 4.46 hp If 0.06018 ,V . 6. For a constant weight of air:. .. , (a) The speed, capacity, and pressure vary inversely as the density. ... . (4) The horsepower varies inversely as the square of the density. ' Example 4. -If the speed of the fan of the previous examples is increased so. as to deliver the same weight of air at 200 F as at 70 F, what will be the Speed, capacity, static pressure, and power? ' Speed = 400 X ^=498 rpm n 074Q5 Capacity = 12,000 X q`o6018 = 14,945 cfm (measured at 200 F) 310 Chapter 17--Fans 0.07495 Static pressure = 1 X 0.06018 1.25 in. Power = 4 X / 0.07495 \ 2 V 0.06018/ = 6.20 hp FAN EFFICIENCY The efficiency of a fan may be defined as the ratio of the horsepower output to the horsepower input. The horsepower output is expressed by the formula: A.i.r.H.orsepower,1 cfm X total pressure in inches of water - --------------------------- ----------------------------------- ... (1) When the static pressure is used in the computation it is assumed that this represents the useful pressure and that the velocity pressure is lost in the piping system and in the air which leaves the system. Since in most installations a higher velocity exists at the fan outlet than at the point of delivery into the atmosphere, some of the velocity pressure at the fan outlet may be utilized by conversion to static pressure within the system, but owing to the uncertainty of friction losses which occur at the places where changes in velocity take place, the amount of velocity pressure which is actually utilized is seldom known, and the static pressure alone may best represent the useful pressure. The efficiency based upon static pressure is known as the static efficiency and may be expressed as follows: _ .. _. . , cfm X static pressure in inches of water Static efficiency* = ------------ 6356 X~Hor^wer input------------ (2) Different fans may develop the same capacity against the same static pressure and with the same power input, and therefore operate at the same static efficiency, while maintaining different outlet velocities. Where a high outlet velocity is desirable or can be utilized effectively, the static efficiency fails to be a satisfactory measurement of the performance. In many applications of propeller fans, air is circulated without encountering resistance and no static pressure is developed. The static efficiency is zero and its calculation is meaningless. .Because of such situations where the static efficiency fails to indicate the true performance, many engineers prefer to base the calculation of efficiency upon the total or dynamic pressure. This efficiency is variously known as the total, dynamic, or mechanical efficiency, and may be expressed as follows: . . ... . , Mechanical or , Iotal efficiency* = c--f-m-----X- .6.3t-o-5-t-6-a--lX--p--r-He--s-o-s-r-us-r-e-e-p-i-on--w-i-en--rc--hi:-ne--ps--u-o7tf--w---a--t-e--r (3) CHARACTERISTIC CURVES In the operation of a fan at a fixed speed the static and total efficiencies vary with any change in the resistance which is imposed. With different designs the peak of efficiency occurs when the fans deliver different per- `See Standard Test Code for Disc and Propeller Fans, Centrifugal Fans and Blowers, Edition of 1932. : 311 American Society of Heating and Ventilating Engineers Guide, 1936 centages of their wide-open capacity.. Variations in efficiency accompany variations in pressures and power consumption which are characteristic of the individual designs and which are influenced particularly by the shape and angularity of the blades. Such variations in pressure, power, and efficiency are shown by characteristic curves. Characteristic curves of fans are determined. by tests performed in accordance with the. Standard Test Code for Disc and Propeller Fans, Centrifugal Fans and Blowers2 as adopted by the American Society of Heating and Ventilating Engineers and the National Association of Fan Manufacturers. The results of tests are plotted in different ways: the j ; ; ; j ; Chapter If---Fans Axial flow fan characteristics are indicated by Figs. 1 and 2. These fans, when properly designed, have a satisfactory efficiency at low resistance, comparing favorably in this respect with centrifugal fans. They are low in cost and economical in operation and occupy relatively little space. Although this type of fan can operate against considerable resistance, the noise often becomes objectionable, so that it does not always compare favorably with centrifugal fans for such service. With most of the designs which employ blades of uniform thickness the power increases rapidly with an increase in resistance. The curves (Fig. 1) show the rapid reduction in capacity and increase in power as the resistance increases. The low efficiency when overcoming Fig. 1. Operating Characteristics of an Axial Flow Fan abscissae may be the ratio of delivery, assuming full open discharge as 100 per cent, and the ordinates may be static pressure, dynamic pressure, horsepower and efficiency. Pressures may be expressed in per cent of the maximum pressure in the manner shown in the illustrations in this chapter, but in engineering calculations they are sometimes expressed in proportion to the pressures due to the peripheral velocity. It should be noted that characteristic curves of fan performance are plotted for a constant speed. Some variation in values of efficiency may occur at different speeds but such variation is usually slight within a wide range of speeds. Fans of similar design but of different size will also show some difference in efficiency. Figs. 1 to 4 show characteristic curves for different types of fans using blades of various shapes, but without reference to the design of housing employed. The efficiency curves are therefore not serviceable for making rigid comparisons of efficiencies obtainable with blades of the various shapes but are intended merely to show reason able values and more particularly to show the manner in which variations occur with changes in fan capacity. - A.S.H.V.E. Transactions ,Vol. 29, 1923. Amended June, 1931. 312 BBHasBPBffiBgasmna^ ^ heavy resistance is due to the low speed of the blades near the hub as compared to the relatively high peripheral or tip speed. The air driven by the blade area near the rim can pass back through the less effective blade area at the hub more easily than it can overcome the duct resistance. Fig. 2 shows the performance of the airplane propeller fan in which the blades are similar in shape to those of an airplane propeller but of varying number according to the pressure to be developed. This fan usually operates at a higher speed than does the former type of propeller fan, and with a different power characteristic, the power remaining fairly constant throughout the range of pressures, being somewhat less at the higher than at the lower pressures. The flatness of the horsepower curve indicates the advantage of this type of fan in preventing overloading of motors where fluctuations in pressure occur. Variations in the diameter, width, pitch, camber, and the thickness of the blades provide a considerable degree of flexibility in design, so that the peak of total efficiency may be . made to occur at wide-open volume or at various percentages of that volume. .. Another advantage of this type of axial flow fan is its low resistance to air passage when standing still. There are some installations in which such a characteristic is desirable. 313 American Society of Heating and Ventilating Engineers Guide, 1936 The straight blade (paddle-wheel) or partially backward curved blade type of fan is practically obsolete for ventilation. Its use is largely con fined to such applications as conveyors for material, or for gases con taining foreign material, fumes and vapors. The open construction and the few large flat blades of these wheels render them resistant to corrosion and tend to prevent material from collecting on the blades. This type of fan has a good efficiency, but the power steadily increases as the static Chapter 17--Fans makes it adaptable for direct connected electric motor drives. The high speed may necessitate somewhat heavier construction and more operating attention or service. The dimensional bulk for a given duty often is 150 per cent of that of a forward curve multiblade type fan. Between the extremes of the forward and the full backward curve blade type, centrifugal fans a number of modified designs exist, differing in the pressure falls off, which requires that the motor be selected with a moder ate reserve in power to take care of possible error in calculation of duct resistance. - The forward curved multiblade fan is the type most commonly used in heating and ventilating work, as it has a low peripheral speed, a large capacity, and is quiet in operation. The point of maximum efficiency for this fan occurs near the point of maximum static pressure. The static pressure drops consistently from the point of maximum efficiency to full open operation. The power curve rises, continually from low 'to peak capacity, but if reasonable care is exercised in figuring resistance there is no danger of overloading the motor. ' The outstanding characteristics of. the full backward curve multiblade type fan are the steep pressure curves, the non-overloading power curve, and the high speed. (See Fig. 4.) This fain operates at a peripheral speed of approximately 250 per cent of the forward curve multiblade type for like results. The pressure curves begin to drop at very low capacity and continue to fall rapidly to full outlet opening. The steep pressure curves tend to produce constant capacity under changing pressures. Where wide fluctuations in demand occur, this type of fan is desirable to prevent overloading of motors. The maximum power requirement occurs at about the maximum efficiency. Consequently a motor selected to carry the load at this point will be of sufficient capacity to drive the fan over its full range of capacities at a given speed. The high speed of this type; 314 '- Fig. 4. Operating Characteristics of a Fan with Blades Curved Backward angularity or in the shape of the blades. Common among these designs are the straight radial blade type, the radial tip type, and the double curve blade type with a forward angle at the heel and a slight backward angle at the tip of the blade. Characteristic curves of these types show varying degrees of resemblance to the curves of Figs. 3 and 4, according to the degree of similarity to one or the other of the two designs of fan considered. SYSTEM CHARACTERISTICS A given fan performs as determined by the real characteristic of the system to which it is attached. When a different performance of a fan is desired, it is necessary to either change the speed of the fan (as A to B or C to D in Fig. 5), or to change the system (as by moving a damper from A to C in Fig. 5). If the speed of the fan is changed, the new point of oper ation is the intersection of the constant speed static pressure--cubic feet per minute curve for the new speed with the system characteristic. If the system is changed, the new point of operation is the intersection of the constant speed static pressure--cubic feet per minute curve with the new system characteristic. Heating and ventilating systems follow the simple parabolic law quite closely but other types of systems follow some other more or less complex relation. The more complex systems can be separated into their com ponent parts whose individual characteristics are known and the sum mation of the characteristics of the several parts of a system will give the composite characteristic of the system. 315 of andAmerican Society Heating Ventilating Engineers Guide, 1936 SELECTION OF FANS The following information is required to select the proper type of fan : 1. Cubic feet of air per minute to be moved. . 2. Static pressure required to move the air through the system. 3. Type of motive power available. 4. Whether fans are to operate singly or in parallel on any one duct. 5. What degree of noise is permissible. 6. Nature of the load, such as variable air quantities or pressures. Fig. 5. Illustration of Operating Points of a Given Fan at Two Speeds on the Same and Different Systems Knowing the requirements of the system, the. main points to be con sidered for fan selection are (1) efficiency, (2) speed, (3) noise, (4) size and weight, and (5) cost. In order to facilitate tl\e choice of apparatus, the various fan manu facturers supply fan tables or curves which usually show the following factors for each size of fan operating against a wide range of static pressures: .- ' 1. Volume of air in cubic feet per minute (68 F, 50 per cent relative humidity, 0.07488 lb per cubic foot). 2. Outlet velocity. 3. Revolutions per minute. 4. Brake power. ' 5. Tip or peripheral speed. '- 6. Static pressure. 316 17Chapter --Fans The most efficient operating point of the fan is usually shown by either bold-face or italicized figures in the capacity tables. Fans for Ventilation and for Cooling Systems Two important factors in selecting fans for ventilating systems are efficiency (which affects the cost of operation) and noise. First cost and space available are secondary. The fans should be selected to operate at maximum efficiency without noise. Because noise in a ventilating system is irritating and a cause for complaint, fans must be selected of proper size in order to reduce it to a minimum. Noise may be caused by other factors than the fan, namely, high velocity in the duct, work, unsatisfactory location of the fan room, improper construction of floors and walls, and poor installation. Where noise is chargeable directly to the fan, it is caused either by excessive peripheral speeds, or the fan is. oh insufficient size. It should be remembered, however, that the tip speed Table 1. Good Operating Velocities and Tip Speeds for Forward Curved Multiblade Ventilating Fans Static Pressure Inches of Wateb X Vs X% X X l IX IX ix 2 2X 2X 3 Outiot Velocity Feet fee Minute 1000-1100 1000-1100 1000-1200 1100-1300 1200-1400 1300-1600 1500-1800 1600-1900 1800-2100 1900-2200 2000-2400 2200-2600 2300-2600 2500-2800 .. Tip Speed Feet per Minute . 1520-1700 1760-1900 1970-2150 2225-2450 2480-2700 2660-2910 2820-3120 3162-3450 3480-3810 3760-4205 4000-4500 4250-4740 4475-4970 4900-5365 . required for a specified capacity and pressure varies with the type of blade, and that a tip speed which may be excessive for the forward curved type is not necessarily so for the backward or slightly backward type. A noisy fan usually is one which is operated at a point considerably beyond maximum efficiency. - For a given static pressure there is a corresponding outlet velocity and peripheral speed wherein maximum efficiency is obtained! If a fain is selected to operate at this point, the cost of operation and the noise can . be held within control. . To aid in selecting fans as near as possible to the point of maximum efficiency, there are listed in Tables 1 and 2 for each static pressure cor responding outlet velocities and tip speeds which will give satisfactory results. The proper tip speed for a given static pressure varies with the design of wheel and with the number of blades or vanes in the wheel. Lower outlet velocities than those listed in Table 1 may be employed, but care must be exercised to avoid selecting a fan for operation below its useful range. The useful range of the fans of Table 2 extends over the full length of the performance curve. . 317 of and' American Society Heating Ventilating Engineers Guide, 1936 In exhaust ventilating systems where the air column moves toward the fan, noise due to the higher tip speeds and outlet velocities will not be so readily transmitted back through the air column to the building as when the air column is moving toward the rooms. Therefore higher outlet velocities may be used, but this will be at the expense of increased horsepower. - Amply large fans should always be used for both exhaust and supply systems, as there may be and usually is leakage despite the most careful workmanship, necessitating the delivery of more air at the fans than is exhausted from or supplied through the openings in the various rooms. Long runs of distributing ducts, heaters, and air washers require definite increments of the total pressure which a supply fan in a venti lating system must overcome. These static pressures should be con sidered when selecting the fan characteristics, speed, and power. Table 2. Good Operating Velocities and Tip Speeds for Multiblade Ventilating Fans with Backward Tipped and Double Curved Blades Static Pressure . Inches or Water Outlet Velocity Feet peb Minute M Vs % V% H Vs 1 iK m 2 2H 2K 3 800-1100 800-1150 . 900-1300 . 1000-1500 1100-1650 1200-1750 1200-1900 1300-2100 1400-2300 1500-2500 1600-2700 1700-2800 1800-2950 2000-3200 Tip Speed Feet peb Minute 2600-3100 3000-3500 3400r4000 3800-4500 4200-5000 4500-5300 4800-5750 5300-6350 5750-6950 6200-7550 6650-8050 7050-8550 7450-9000 8200-9850 Fans picked within the limits of Table 1 will operate close to the point of maximum efficiency. No attempt has been made to select these limits for quiet operation, since this is a relative term and varies with the type and location of the installation. The connection of a fan to a metallic duct system should be made by canvas or a similar flexible material so as to prevent the transmission of . fan vibration or noises. Where noise prevention is a factor the fan and its driver should have floating foundations. , ' Fans for Drying ' Both axial flow and centrifugal types of fans are used for drying work. Propeller fans are well adapted to the removal of moisture-laden air when operating against low resistance and when handling air at low tempera tures. Motors on these fans usually are of the fully-enclosed moisture- proof types so that, saturated air or air containing foreign material will not injure the motors. =" Unit heaters employing axial flow fans are widely used in the drying 318 , .- Chapter 17--Fans field. In drying, these fans may be used with unit heaters where not too much duct work is required and where air is to be delivered against pressure, since the noise developed from the high peripheral speed of these fans is not ordinarily objectionable in process work. Centrifugal fans of the multiblade type generally are selected to supply air for drying, as they are capable of delivering large volumes of air against all pressures likely to be encountered. ,' Belt driven fans usually are to be preferred to direct-connected fans since efficient motor speeds do not usually coincide, with efficient fan speeds. Replacement of a standard motor is quick and easy if it is belted. Wherever drying is done throughout the year and where air require ments change as the drying conditions change, the drying can be speeded up or reduced through control of the fan capacity. This may be done by changing the fan speed or by varying the outlet area with dampers. A throttled outlet reduces the volume and reduces the power. Due to the low speeds of forward curved multiblade or paddle-wheel type fans, these can be direct-connected to reciprocating steam engines, and the exhaust steam from the engines may be used in the heating apparatus. In selecting engine driven fans for drying processes, where a large quantity of exhaust steam is used in the heaters, a smaller fan and greater power consumption may be used, because power economy is not essential under this condition. Where static pressure in a dryer varies, and where several fans must operate in parallel, fans are to be preferred which have a continuously rising pressure characteristic, such as is given by backward-curved or double-curved blades. This type of fan is well adapted for direct-con nected motors of the higher speeds. (See Chapter 41 on Drying.) Fans for Dust Collecting and Conveying The application of fans for handling refuse, dust, and fumes generated by machine equipment is covered in Chapter 21. Information is given regarding the methods for determining air quantities, the velocity required for carrying various materials and the method of determining maintained resistance or total static pressure at which the fan is to operate. The selection of a proper size fan is at times governed by the future require ments of the plant. In many instances, additional future capacity is anticipated and should be provided for. Having determined the necessary volume of air and the maintained resistance or static pressure required, the proper size fan may be selected from the fan manufacturers' performance charts or capacity tables. The fan chosen should be the size that will provide the required ultimate quantities with the minimum power consumption. FAN CONTROL Some method of volume control of fans usually is desirable. This may be done by varying the peripheral velocity or by interposing resistance, as by throttling-dampers. Both methods, since they reduce the volume of air, reduce the power required. In many installations adjustments of volume are desirable during varying hours of the day. In others an 319 of and 1936American Society Heating Ventilating Engineers Guide, So! BC i "es> o 00 ^ e :8 Si > t3 ^ <0 320 17--Chapter Fans increased supply of air in summer over that needed for winter is demanded. Experience is required in deciding whether speed-control or dampercontrol shall be used for specific cases. Where noise is a factor, it may be exceedingly desirable to reduce the speed at times, while on the other hand, any fan which has its normal speed reduced as much as 50 per cent without change in resistance will move only 50 per cent of the air. ( DESIGNATION OF FANS i Facing the driving side of the fan, blower, or blast wheel, if the proper direction of rotation is clockwise, the fan, blower, or blast wheel will be designated as clockwise. If the proper direction of rotation is counter-clockwise, the designation will be counter clockwise. (The driving side of a single inlet fan is considered to be the side opposite the inlet regardless of the actual location of the drive.)* . This method of designation will apply to all centrifugal fans, single or double width, and single or double inlet. Do not use the word "hand," but specify "clockwise" or "counter-clockwise." ^ The discharge of a fan will be determined by the direction of the line of air discharge and its relation to the fan shaft, as follows: . Bottom horizontal: If the line of air discharge is horizontal and below the shaft. Top horizontal: If the line of air discharge is horizontal and above the shaft. Up blast: If the line of air discharge is vertically up. . Down blast: If the line of air discharge is vertically down. All intermediate discharges will be indicated as angular discharge as follows: Either top or bottom angular up discharge or top or bottom angular down discharge, the smallest angle made by the line of air discharge with the horizontal being specified. In order to prevent misunderstandings, which cause delays and losses, the arrangements of fan drives adopted by the National Association of Fan Manufacturers and indicated in Fig. 6 are suggested. If double width, double inlet fans are selected, care must be taken that both inlets have the same free area. If one inlet of a fan is obstructed more than the other, the fan will not operate properly, as one half of the wheel will deliver more air than the other half. The backward, curved and double curved types with backward tip operate satisfactorily in double or in parallel operation. . MOTIVE POWER It is no easy matter to predetermine the exact resistance to be encoun tered by a fan or, having determined this resistance, to insure that no changes in-construction or operation shall ensue which may increase air resistance, thus requiring more fan speed and power to deliver the required volume, or which may reduce air resistance, thus causing delivery of more air and a consequent increase of power even at constant speed. It is recommended, therefore, for centrifugal type fans that the rated power to be supplied shall exceed the rated fan power by a liberal margin; when forward curved types are used. When backward or double curved blade types are used, motors with ratings very close to that of the fan horsepower demand can be employed, provided the fan has a limiting horsepower characteristic. ', 'Recommendations adopted by the National Association of Fan Manufacturers. 321 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Justification for liberal power provision exists also in the possibility of varying demand due to changes in ventilation requirements, intensity of occupation, and weather conditions. ' The motive power of fans should be determined in accordance with the Standard Test Code for Disc and Propeller Fans, Centrifugal Fans and Blowers, as adopted by the American Society of Heating and Venti lating Engineers and the National Association of Fan Manufacturers. Fans may be driven by electric motors, steam engines (either horizontal or vertical), gasoline or oil engines, and turbines, but as previously stated the drive commonly used is the electric motor. REFERENCES Heating, Ventilating and Air Conditioning, by Harding and Willard, Revised Edition, 1932. Fan Engineering, Buffalo Forge Company. Theories and Practices of Centrifugal Ventilating Machines, by D. Murgue, trans lated by A. L. Stevenson. Mechanical Engineers' Handbook, by Kent. . Mechanical Engineers' Handbook, by Lionel S. Marks. Constructive Mechanism and the Centrifugal Fan, by George D. Beals. . Coal Miners Pocket Book. The Fan, by Charles H. Innes. . . Mine Ventilation, by J. J. Walsh (A.S.H.V.E. Transactions, Vol. 23, 1917). Fan Blower Design, by H. F. Hagen (A.S.H.V.E. Transactions, Vol. 28, 1922). The Centrifugal Fan, by Frank L. Busey. * Section X, A.S.H.V.E. Code of Minimum Requirements for the Heating and Venti lation of Buildings (Edition of 1929). . PROBLEMS Ii\T PRACTICE 1 What information must be supplied to the manufacturer when ordering a centrifugal fan? a. Size of fan (catalog number). b. Type of fan. c. Width of fan (single or double). d. Number of inlets (single or double). . . . N' ' ' . Fan performance and kind of application. /. Direction of rotation (clockwise or counter-clockwise). 'v g. Direction of discharge (top horizontal, down blast, etc.). - h. Drive arrangement (see Fig. 6). '. i. Style of housing (full, three-quarters, etc.). , : 2 9 In selecting fans for quiet operation in public buildings: . ' a. Should the outlet velocity of the fan be limited? ' b. Should the tip speed of the fan be limited? a. Because all commercial fans operating at pressures suitable for this class of work would be considered noisy if the fan were to discharge directly into the room-, and 322 ' Chapter 17--Fans because the duct system on the fan discharge is depended upon to absorb a reasonable amount of fan noise, it is desirable to have a moderate run of duct work with some bends and elbows included as sound deadeners. Where this duct is of necessity very short, the outlet velocity must be kept down to the lower limits recommended in this chapter or else an efficient sound absorber must be used. The experience of the engineer must be his guide in determining the allowable outlet velocity in each individual case. b. Tip speed should not ordinarily be limited, because different types of fan blades have entirely different allowable tip speeds for quiet operation. A fan having a backward blade at the tip can run at much higher tip speed than can a forward curved or a straight blade fan, with the same degree of quietness. 3 Is a direct connected or a belted fan preferable in public building work? Where space is at a premium, direct connection is best. Next in space economy is the short V-belt drive. The flat belt drive fan requires the greatest floor space. In this class of work, pressures are usually so low that even with the high speed fans the motor cost is greater for direct connected units than for belt drive fans. a. What type fans are used in industrial work? b. What outlet velocity is suitable? a. All of the centrifugal types are suitable; the disc and propeller types are suitable for low pressure work, or they are often used as exhausters. b. The outlet velocities on fans for industrial work can be much higher than can those in public building work, where quietness is essential. Fans should be selected with outlet velocities as recommended in this chapter, using the upper limit of velocities. 5 9 Are direct connected or belted fans preferred in industrial work? In industrial applications, fans are often advantageously direct connected to motors. .The pressures are usually high enough to use standard motor speeds. The high speed /types of fans have limiting horsepower characteristics so that little margin in power must be provided in the driving motor. Belted fans may be used, but where high power is required a special arrangement is often necessary for shaft and bearings on account of the weight of the sheave and the belt pull. 6 A forward curved multiblade fan which requires 5.4 bhp is delivering 22,800 cfm at 70 F against a resistance pressure of 1 in. of water at an outlet velocity of 1440 fpm: a. What is the static efficiency? b. What is the total efficiency? a. 66.3 per cent (see Equation 2). b. 74.5 per cent (see Equation-3). 7 9 If the above fan has a 54-in. diameter wheel and operates at 193 rpm, will it be suitable for a ventilating installation where a minimum of noise is desirable? Yes. The tip speed will be 2720 fpm and this, together with the 1440 fpm outlet velocity, falls within the limits given in Table 1 for 1-in. resistance pressure. 8 9 What objectionable feature is inherent in the ordinary propeller fan when it is operating at high resistance pressures? It must operate at a high speed with consequent noise. 9 9 At what point should a fan be selected for operation, and why? At its, point of maximum efficiency because the cost of operation and the noise produced will be least. '" American Society of Heating and Ventilating Engineers Guide, i936 10 O In Fig. 3, a static pressure of 85 per cent of blocked tight pressure cor responds to three different volumes, namely 11 per cent, 30 per cent and 48 per cent of wide open volume. What will determine which volume the fan delivers? The fan can operate only at the intersection of its pressure-volume curve and the system characteristic. -The type of system, together with the specification of the volume at a certain static pressure, completely defines the system characteristic. As illustrated in Fig. 5, a given system characteristic will intersect the fan curve in only one point. If the 85 per cent value for static pressure is specified for the 48 per cent value of volume, it is at once obvious that the same system will not have the same resistance at any other volume. 324 Chapter 18 SOUND CONTROL Measurement of Noise, Noise in Buildings, Coefficients of * Absorption, Insulation of Air-Borne Sound, Location and Insulation of Equipment Room, Insulation of Machinery and Solid-Borne Vibration, Control of Noise Transmission Through Ducts9 Effect of Humidity upon Acoustics THE ventilating and air conditioning of any space affect its acoustics and become apparent when consideration is given to the require ments for good hearing in any architectural interior. The requirements which must be given careful study are: 1. The room should be free from noise, whether of inside or outside origin. 2. The useful sound, whether speech or music, should be sufficiently loud (with reference to any residual noise) to be heard easily and distinctly. , 3. The useful sound should be distributed uniformly in all parts of the room, and the sound reaching the listeners should be free from long-delayed reflections which produce interference or echoes. 4. The room should be free from pronounced resonant tones which may result from either volume or panel resonance. 5. The room should contain sound-absorptive materials in such amounts, and of such qualities, as will provide a proper balance between the persistence and cessation of the articulated components of sound, that is, the reverberation in the room should be long enough to sustain harmony and impart tonal blending to music, and at the same time it must be short enough to prevent the overlapping and confusing of the separate sounds of speech. Obviously, the first of these requirements is the one which imposes restrictions on the installation of air conditioning or ventilating equip ment--theequipmerit noises must be unobjectionable in occupied rooms-- although the fifth requirement is riot entirely independent of the humidity and temperature of the air. LOUDNESS Loudness is .the sensation of sound intensity. When it is said that one sound is louder than another a difference in intensity level is implied. Two identical whistles when sounded together do not make a sound twice as loud as one. It may take ten to make a sound 20 per cent louder than one. Jt has been found that loudness bears a logarithmic relationship to intensity of sound. On this basis a scale of loudness has been built and a unit, the decibel (db), has been established. This scale is illustrated in Fig. 1 which shows the loudness of some typical noises. The formula for relating loudness and intensity is: Z.i -- Z.j = 10 logio -y1 (1) 325 American Society of Heating and Ventilating Engineers Guide, 1936 where L = Loudness in db. I = Intensity. ' . Thus the two whistles made a noise 10 logio 2 = 3 db louder than one whistle and the ten whistles, 10 logio 10 = 10 db louder than one. It would take a hundred whistles to make a noise 20 db louder than one and a thousand to make a noise 30 db louder. MEASUREMENT OF NOISE Since the chief acoustical problem in the ventilating or air conditioning of a building consists of reducing equipment noise, it is necessary to describe methods for measuring noise. The measurement of noise is a relatively new problem, and although there are several reliable methods, there are as yet no standardized units, scales, or instruments for measuring noise1. However, the decibel (db) already described is widely used in this country and England as the standard unit for noise or sound intensity--a unit of the same size, but called a phon, is used in Germany--and the zero level of the scale is a barely audible sound. Since the relation between subjective loudness and sound intensity is dependent upon pitch, it is customary to refer loudness to a single frequency. A 1000-cycle tone is generally accepted as the reference frequency, that is, the loudness of any sound is rated in terms of an equally loud 1000-cycle tone. Thus, a noise of 50 db means that the noise would be judged to be of the same loudness as a 1000-cycle tone which is 50 db above the normal threshold of audi bility for the 1000-cycle tone. As the frequencies decrease below 1000 cycles, the ear becomes less sensitive, until at about 30 cycles, sounds are no longer audible regardless of their intensity. Similarly, for higher frequencies, the limit of audi bility is reached around 7000 cycles. Thus, at frequencies below 1000 cycles, sounds of the same loudness must have a greater intensity than at 1000 cycles. This is particularly fortunate, as otherwise the low fre quency sounds would mask all others. Noise measurements are usually made by one of three methods. The first is the electrical instrument method, which uses a noise meter usually consisting of a microphone, an amplifier, and a galvanometer. Where such a meter is to measure the loudness of a noise without regard tp the frequency distribution, it must contain a weighted network which elec trically simulates the varying sensitivity of response of the ear to different frequencies. Where it is desired to analyze the character of the sound, filters which shut out all but certain bands of frequencies are used with the meter. A number of manufacturers make such meters. The second method consists essentially /of varying the intensity of an artificially generated sound until the' noise generated is masked by the noise being measured. Obviously, this method is subject to human errors in observation to which the instrumental method is not, but in the hands of 1See Proposed Tentative Standards for Noise Measurement, and Proposed American Tentative Standard Acoustical Terminology of the American Standards Association Sectional Committee on Acoustical Measure ments and Terminology. *. Also see How Sound is Controlled, by V. O. Knudsen (Healing, Piping and Air Conditioning. October, 1931), and Acoustical Problems in the Heating and Ventilating'of Buildings, by V. O. Knudsen (A.S.H.V.E. Transactions, Vol. 381 1932). 326 Chapter 18--Sound Control a careful observer quite satisfactory results may be obtained. One instrument used is the audiometer, which consists of a buzzer, an ear phone, and a rheostat. The phone is held a fixed distance from the ear while the resistance of the rheostat is varied until the sound of the buzzer, as transmitted electrically to the phone, can no longer be heard. Audio meters are available either for covering all frequencies, as in the noise meter, or for covering certain frequency bands only. A third method of measuring noise, simple, yet sufficiently accurate for most field measurements, employs only three tuning forks and a stop watch. Forks having frequencies of 128, 512, and 2048 are recommended. The forks must be calibrated. That is, it is necessary to know for each fork (1) the initial intensity, in number of decibels above its threshold, immediately after it has received a standard hit or excitation, and (2) the damping rate, in decibels per second. These calibrations can be made in any well-equipped acoustical laboratory. A standard hit or excitation can be imparted to the fork by a felt-covered spring hammer, or simply by letting the fork fall from a vertical position through an arc of 90 deg, hitting a suitable pad (such as soft rubber or felt for the 128 and 512 forks and hard rubber for the 2048 fork). The average 512 steel fork will have an initial intensity, when held )/i in. from the ear with the broad side of the prong facing the ear canal, of about 80 db, and will decay at a rate of about 1.0 db per second. Such a fork will remain audible about 80 sec in a perfectly quiet place, provided the listener has normal hearing. In the presence of a noise, it will remain audible until its tone is just masked by the noise. Thus, if a 512 fork, having an initial intensity of 80 db and a damping rate of 1.0 db per second, should be found to remain audible 35 sec in the presence of a certain noise, the masking effect of the noise is 80 -- 35, or 45 db. Procedure * . . The method of measuring any noise is as follows: The observer, in the presence of the noise, strikes the 128 fork a standard blow. At the same instant he starts a stop watch. The fork is then held in front of the ear canal, and moved back and forth slightly, until the tone of the fork is just completely masked by the noise, at which instant the watch is stopped. This measurement is repeated at least two times. The average time is subtracted from the time the 128 fork remains audible in a quiet place. This difference multiplied by the damping rate of the fork gives the mask ing effect of the noise at 128 cycles. Similar measurements are made with the 512 and 2048 forks. Measurements of this type give a satisfactory description of both the intensity and the frequency distribution of the noise. The average masking effect of the noise at 128, 512, and 2048 cycles will usually be about 5 to 10 db less than the reading given by a noise meter. . NOISE IN BUILDINGS Measurements of the intensity of speech, music and noise in many buildings, with special consideration of the noise produced by ventilating equipment, have given the results indicated by Fig. 1. The equivalent loudness of sounds in buildings varies from less than 10 db near the outlet of an air duct in a very quiet sound studio to nearly 100 db in a noisy boiler factory. It will be noted that the noise from the ventilating 327 . American Society of Heating and Ventilating Engineers Guide, 1936 fan in a certain high school auditorium was nearly as loud as average speech in a large auditorium. Such an amount of noise is devastating to good acoustics; in fact, it is impossible to hear speech in the presence of such a noise. db. 100 **- Boiler Factory 90 -Electric Power Substation 80 *- Ventilating Room for Large Hotel (Very Noisy) Average Loudness of Music in Room-* 70 Conversation in a Small Room-* --Inside of Duct, near Large Low Speed Fan -Equipment Room I Average Condition 1 .' 60 -Fan Room for School Building i Rather Quiet) Speech in a Small Auditorium-* -Guest Room. Large Hotel on Noisy Street (Windows Open) bO Speech in a Large Auditorium-* ^_Near Outlet of Ventilating Duct in High School Auditorium I Very Noisy,no*Fi!ters*in Duct! 40 - Fan Noise in Theater < Poor Control of Noise) 30 20 fan Noise tn Theater < Proper Control of Noise 1 10 Near Outlet of Ventilating Duct in M. G. M. . Sound Studio < Planned Control of Noise ) Fig. 1. Chart Showing the Equivalent Loudness (in Decibels) of Speech, Music, and a Number of Noises Incident to the Ventilating of Buildings3 Acoustical Problems in the Heating and Ventilating of Buildings, by V- O. Knudsen (A.S.H.V.E. Transactions, Vol. 38, 1932). . In every problem of noise reduction in buildings it is necessary to know how much noise can be tolerated. The noise levels given in Table 1 may be regarded as completely inoffensive. They represent what might be' termed ideal conditions, not often realized in existing buildings. How ever, they represent conditions which can be attained by proper control of noise, and heating, ventilating and air conditioning engineers should aim to provide the degree of quiet specified in the table. In considering the tolerable room noise level due to heating, ventilating, or air conditioning apparatus, not only must the absolute value of the noise be considered but also its relation to the room noise level without the apparatus running. This is necessary since a large increase of noise subjects the apparatus to serious criticism even though the level may be low. It must also be borne in mind that the noise produced by the ap- 328 Chapter 18--Sound Control paratus is additive to that of the room without apparatus.. Thus if the two are equal, when combined the noise level.will be. 3,db: higher;;: For, these reasons the room noise caused by the apparatus should not exceed the other room noise. ' Noise Control , , , . , < ......... - , . ,, , Essential to the design of a satisfactory system arc:.first, a. knowl edge of the nature and intensity of the noise generat^d by the 'various parts of the equipment; second, a knowledge of how to vary the noise level' between ;the apparatus .And the. conditioned-irodm_ if (need be; third, a knowledge of the acceptable level of apparatus'noise in ;the con ditioned. room. Besides these, the. engineer rnust be able to'deal with' other noises. which might enter the rpbm wheniopeningsAr^ such as cross fohfc between rooms connected with common ducts, and hpie , (if:.:/.. Table!.Acceptable Noise Levels:.: .:i u.J i' Talking picture, stiffiiqs:::..--.--........ .............. 6 tcT .8'"db` " Radio btoadci4sttog-ittadi<)S!:LviL.:Lu:u;;.;L.TMvA-.`..cu..L;Li.Uj;i..-.-._A..L. , ; 8 toiiO/db . 8 to 12-db Music studios--.,.-------- ,.................... -------- --............... .............................. ,. , 10 to 15 dl>', > Apartments, hotels, homes, small'private offices, 10 to 20 db'' ", Theaters, churches/ auditoriums, ^classrooms, libraries;_ 12 to 24 dB- Talking picture theaters, sttiall clothing stores____ ;......-;....... General.cSflfides-j:-.r;--ci-c..---- : 15 to,25db:Oi ,2p toAOdhiA Large public , offices;, banking rooms, upper stories of; department, stores, restaurants,.barber shops.. .. .......... ......." ` ' 25 io 35 db Grocery stores,'-drug stores--Accounting and;typewriting/offices..1;.:.;..'.;;;.:..;:;..!..;.; j. 30; to 50 db -- 35,to 45:db; :n Main floor of department stores...... . . j.l . ...... * 40 tQ.50 'db transmitted to poftibhs-of duct systems outside the conditidned-rooni and; thence to its interior. y--v ; 5 ' V! .y The problem of apparatus ii6ise i$ `fecdiviffg' the study of equiprrient manufacturers who are aiming "at; both ndise reduction and standardiza tion: Some manufacturers' now' have noise ratings available for their equipment, while some pass each unit of equipment of . Certain types through-sound tests durihg thecOurSeofmanufacture.11 ? ' '-.'O ROOM NOISE LEVEL, COEFFICIENTS OF ABSORPTION The problem of noise reduction from apparatus to room must take into consideration and treat separately the three modes of travel of noise to the room; Aril, from the apparatus through the air to the walls of the room and thence :to its interior; iecowd, ;thfoUghvthe building structure to the room ; third, through ducts Or openings to; the ,room; Because the noise entering-by- each of these-'three channels is susceptible^to'quantitative analysis,, solutions are' available. -Along with the transmission of, sound through the building structure, the engineer must also consider the transmission Of vibration, Which may also be objectionable. The solution5 is not complete, however, until the effect of the noise entering the room on the room;noise: level is determined. : - - /' ir-', : -T ; : :> ' , : One of the most effective means'Of reducing hoises in ventilating equip ment is accomplished by the proper covering of the interior walls and 329 American Society of Heating and Ventilating Engineers Guide, 1936 ceiling of the equipment room, or the inner walls of the ducts, with soundabsorptive materials. The intensity 7 of a continuous sound in a room is where . E rs' I = -- or ------aa (2) E = the rate of emission of the noise source = P S'. (The intensities of noises entering the room times the areas through which they enter.) a = the total amount of absorption supplied by the boundaries and contents of the room. = aiSi + a,S, + aiSt + ............ where Si, St, S,.............. are the areas of the boundary materials for the room, and on, a,, a,,........... are the corresponding coefficients of absorption. . Hence, by increasing tenfold the absorptivity of the boundaries of a room it is possible to reduce tenfold the average intensity of souad in the room; that is, the intensity level would be reduced 10 db. Thus it is possible to compute the noise level in the room if the intensity of noises entering the room or generated in it are known. It will be seen that the noise intensity reduction is dependent upon the amount of sound absorption in the room, and that the first units of absorp tion are more effective than succeeding units. In general, the room noise level will be from 10 to 20 db lower than the air inlet or outlet noise intensity, the 10 db being in the case of bare rooms having large venti lating or air conditioning openings in relation to their size, and the 20 db in the case of rooms having large amounts of absorptive matericd with small openings. In some cases, the noise level reduction may run up to asmuch as 30 db, but then the higher sound intensity adjacent to the openings tends to nullify the effects of the extra reduction. Where these openings are large, the local effect on the noise intensity extends some distance from the opening; for instance, a four-square-feet opening might have a local effect within ten feet, while a one-half-square-foot opening would have a local effect within only five feet. The coefficients of: sound-absorption for a number, of standard absorp tive materials used, or suitable fgr use, in equipment rooms are given in Table 2. Coefficients are given for frequencies of 128, 512, and 2048 cycles. Where the frequency of the noise is not known, the values for 512 or 128 cycles are usually used. . INSULATION OF AIR-BORNE SOUND The transmission of air-borne sounds through rigid partitions is. accom plished primarily by the diaphragm-like vibrations of the partition. The weight per square foot of the wall is the determining factor, and the insulation value of a wall, in terms of the transmission loss in decibels, is proportional to the logarithm of the weight per square foot. Other factors, such as size, stiffness, composition; manner of mounting, and the use of multiple structures separated by-air spaces or flexible connectors, contribute, to the effective insulation. If the coefficients of sound trans mission of-different types of structures-and the noise intensity in the space adjoining a room are known, it is possible to calculate the noise intensity in a room by the use of formula 1 and the following formula: r= (3) 18Chapter --Sound Control where . J" = noise intensity in space adjacent to room. t = coefficient of sound transmission. . Coefficients of sound transmission for some common walls are shown in Table 3. ' Example 1. Suppose the brick wall between an equipment room and an adjacent auditorium has an area of 200 sq ft and a coefficient of sound of 0.00001 (see Table 3); that the auditorium contains 2000 sabines* of absorption; and that the noise level in the equipment room is 70 db above zero level. . pi 70 _ 0 = 10 Iogio -y- (from Formula 1) to ' ' J-- = 107 X 0.00001 lo 100 (from Formula 3) 4- = 100 X = 10 (from Formula 2) Io 2UUU Table 2. Coefficients of Sound Absorptions Material Thickness (Inches) Acoustex 60, spray painted-- ------ - Acousti-Celotex, Single B...... -............... .......... .Acousti-Celotex, Triple B.i.............. ..................... Acoustic Flexfelt---------- ---- :.......................... Acoustone........................................................... Akoustolith plaster---- 1----------------------- Akoustolith A, Tile...... -................:--------- Brick wall, unpainted.. ...................... ~i--- Calicel____ --............................... .... Corkoustic, Type C. .........................--. i k I_K_ i K l 18 1 m Insulite Acoustile, Type 44.--............ --.... Halite, with three coats lacquer__________ --Macoustic Plaster, stippled to depth of in. Masonite__ . ....... ............... Plaster, gypsum on hollow tile..... ..................... i% K K Ke Plaster, gypsum, scratch and brown coats on metal lath on wood studs.. .................... Plaster, lime, sand finish, on metal lath............... . k Poured concrete, unpainted Rockoustile.. ___ ..... ......................... i Sabinite.......... ........ K Sanacoustic Tile__ _________ i IK Stuccoustic Plaster, Type XB............. ....... Transite Tile. _ ...... .......................h__ K l Trutone Tile__________ 1................. . Wood sheathing, pine............... .......... __ IK .K Wood, varnished *' CosmciENTS or Sound Absorption 128 Cycles 512 Cycles 2048 .Cycles 0.16 0.11 0.20 0_.;_27 0.21 0.14 0.024 0.23 0.08 0.035 0.26 0.35 0.13 0.18 0.013 0.51 0.45 0.75 0.56 0.66 0.29 0.48 0.031 0.72 0.61 0.027 0.50 0.43 0.31 0.32 0.020 0.72 0.68 0.67 0.68 0.69 0.37 0.83 0.049 0.71 0.64 0.020 0.61 0.45 0.58 0.33 0.040 0.020 0.038 0.010 0._18 ' 0.19 0.29 0.19 0.31 0.098 0.05 0.040 0.060 0.016 0.57 0.34 0.79 0.59 0.810.57 0.10 0.03 0.058 0.043 0.023 0.72 0.49 0.74 0.72 0.72 0.64 0.082 0.03 Architectural Acoustics, by V. O. Knudsen, pp. 219, 220, 240-251. A sabine is 1 sq ft of totally absorptive surface. 331 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Room loudness = 10 logic 10 = 10 db If the sound absorption in the auditorium had been as small as 200 sabines, the sound intensity in the auditorium would have been 10 times as great and the noise level in the auditorium would have been 20 db. .: : If the rest, of the auditorium has an area. of .20,000 .sq ft with a surrounding noise intensity of 50 db (/" = 10s) the noise level due to all ot the noise entering through the wall would be found as follows: = 10s X 0.00001 - 1 :, . '' . :' = 10 (Through equipment wall) + 1 X ^200(3^ = ^ Room loudness X 10 logio 20' = 13 db ...... ' . Now suppose that there is also a duct having 20 sq ft outlet connecting the room with apparatus having a noise level of 70 db (/" = 107) and suppose that there is an assumed attenuation in the duct equivalent to a transmission factor of 0.0002. Then, -f- = l0r X 0.0002 = 2 X 10* T 1 -20 ~Y~ ~ 20 (from above) + 2 X 10* X 2000 `: =^ ...... ' ' ;- ' " Room loudness = 10 logio40 --10 db ' ;"* vt r v. . It may be seen how the energies of noises entering a room are added to obtain the fi.n..al roo- m... n...o.is..e .in--t.ensity. ; .; .. j :. .' , ,'' . The average coefficients of sound transmission (128 to 4096 cycles) for a number of walls and of floor and ceiling partitions are: listed in Table 3. Table.3.; Average!Coefficients of Sound Transmission for Building Partitions? . , ; . ' ' ; . : `..DEScaiPpibN 0? Partition ` ; , 1 Average- 'QOEFFICrENT ..' Brick parjel, Mississippi;&mi; plastered'both sides gypsum brown. coat, smooth: white finish,;, good workmanship...................................... 0.000010 ' Brick wall, 2)4-in. plaster both sides......................... .-- ----- --------;----.------ ; 0:000032 Brick wali,'2H-jn., 2-in. furring strips, H;`n..rigid.insuIation iath plastered o.i)ooo(n(>botp sides.:-...-...J,_____ ::--------- .1--................... Brick' wall, 4 in.) 2-in. furring strips and $$-m. rigid insulation lath, plaster, 0.0000040 Concrete flat slab fljoor cdnstrtictiori,' reinforced*?; floating floor; consisting of .nailing: strips, rough and'finish flooring; ^-ln.rigidmsulationfurred 0:0000020: 0.0010 Glass, plate fj-ih. double glared, lM-in. separation...--......................------------,-- VO,0001 Metal: lath, double,| onlJl-inL channels, %:in. gyjp^^/pUdter^tniEout cross bracing clipS; 4 in.,;cohnected at_edges only.......... O.OOOOlf); Tile, hollow day-partition, three cells, 4 in. x 12 in. x 12-m., wood-furring strips, ^in. dgid insulation; gypsum brown coat, smooth white finish.-- 0.0000050 Wood joists, lower sidejplastefed .on: wood lath; floating floor consisting of nailing strips) -rough and .finish flooring-----------------------------....;................,.---------:---------- - Wood studs, two Ji-in. sheafs rigid insulation both sides, joints filled; gypsuni scratch and brown coats/smooth white finish--------------------- ------ ------------ 0.0000050 0.000013 Wood studs, 2 in: x 4 in., -g3T?stin:,plaster; 0.000040 . Architectural Acoustics, by V. O. Knudsen, pp. 308-322;" 332 1 18--Chapter Sound Control LOCATION AND INSULATION OF EQUIPMENT ROOM The equipment room, if possible, should be located at a considerable distance from all rooms in which quiet is required. If this is not possible; it is necessary to provide a high degree of insulation against the noise which may be transmitted through the walls of the equipment room, and also against the noise which almost certainly will be communicated through the short ducts. (See discussion of Control of Noise Trans mission through Ducts, p. 337). Three wall sections and two floor and ceiling sections which' are satisfactory for the wall insulation of the equipment room are shown in Fig. 2. Other partitions, with their sound insulating values, are listed in Table 3. The addition of absorptive materials (such as are described in Table 2) to the inner walls and ceiling M. ^ "^4 Bnck 'z < Z *'l Plaster iI Insulation Value947 db 4 Hollow-Clay Tile l"x 2" Furring Strips Paper and Metal Lath Plaster Insulation Value - 52 db. Absorptive' Blanket l" P2 Fibre Board Insulation Value Greater than 50 Pdbla.ster -Staggered Wood Studs - -^Absorptive Blanket--^-Piaster on Lath . Insulation Value 50 db. ^Concrete Slab 3 Resilient Hangers t Plaster on Lath insulation Value9 60 db'. or more . Fig. 2. Three Wall Sections and Two Floor and Ceiling Sections which are Suitable, for the Insulation of Equipment`Rooms3! ..;.. .. . ^Acoustical.Problems, in the Heating and Ventilating of Buildings,-by V; O- Knudsen (A5.H.VE Transactions,'Vol. 38; 1932); s' of the equipment room will not only increase the-insulation through the walls, but will also -reduce the intensity-of the noise in the room, -The equipment room noise intensity may be figured in the same way as.that of the conditioned spa.ee, taking the equipment as the source of noise. ..In case the equipment is subject to considerable vibration it is advisable to provide a separate or floated floor. . .; INSULATION OF MACHINERY AND SOLID-BORNE VIBRATION Since mechanical vibrations are readily transmitted through the solid structure of a- building, it is extremely important in air conditionihg that all mechanical equipment in which vibrations are generated be- thoroughly insulated from the solid structure of the building: An almost universal notion prevails that the vibrations generated by machinery can be in sulated from a building simply by placing a slab of cork or a layer of hair felt between the machinery' and the floor- of the room. If the ma chinery is sufficiently heavy, and the cork or felt sufficiently resilient, this expedient may suffice. On the other hand, if the machinery is not sufnciently heavy to load the cork or felt support to the extent that the 333 . of and 1936American Society Heating Ventilating Engineers Guide, natural frequency of. the 'machinery on the cork or felt is low in com parison with the frequency generated by the equipment, the cork or felt may be of little avail. The insulation of vibration can be accomplished by means of suitable elastic supports or suspensions, but the design of these elastic supports should be based upon calculation rather than guess-work. . The theory of the. insulation of vibration was first worked out by Soderberg3. If a machine of mass'.m be supported by an elastic pad the amount of vibratory force communicated by the machine to the floor or foundation upon which it rests will be determined by the elastic and viscous properties of, the pad. The ratio of the vibratory force com municated to the. floor or foundation with the machine resting upon the pad, and with the machine resting directly upon the floor, is given by the following equation: r' + 4x*n*cs + (2xnm ~ db)2 (4) where t1 = the so-called trdnsmissibility of the support. c = the compliance (that is, the reciprocal of the force constant). r = the mechanical resistance owing to the viscous forces within the support, n = the frequency of vibration generated by the machine which is to be insulated, such as the commutation frequency of a motor or the blade frequency of a fan. , m = the mass of the machine to be insulated. . It should be noted that not only must vibrations within the audible range of fre quencies be considered, but those in the sub-audible range as well, since these may cause objectionable vibrations. All the possible frequencies should be considered in the calcu lation. Sometimes beat effects are introduced by slight in-egularities of belts or pulleys that have much lower frequencies than those of the rotating elements. If the pad is to be of any value in the prevention of solid-borne vibra tions, the value of t1 must be considerably smaller than unity. If the fundamental frequency of vibration generated by the machine happens to coincide with the natural frequency of the mass of the machine resting on the elastic pad, a condition of resonance will be established, and the machine will exert a greater force upon the foundation than it would if the pad were completely removed: It is necessary, therefore, that the elastic support be sufficiently compliant, \ind the mass of the machine sufficiently heavy, that the natural frequency of the mass m upon its elastic support will be-low in comparison with the frequencies `which are generated by the machine. Thus, if the principal , vibrations in the machine be of the order of 100 vibrations per second, the natural.frequency of the machine mounted on its elastic support should not exceed about 50 vibrations per second, and for best results preferably 20. . When the forced frequency is low, it is frequently impossible to insulate for the fundamental forced frequency due to connecting pipe work and other relevant factors. In cases of this kind an effective installation of- *C. R. Soderberg. The Electric Journal (January, 1924), and succeeding articles. See also V. O. Knudsen. Physical Review, Vol. 32, 1928, p. 324, and A. L. Kimball, Journal Acoustical Society of America, Vol. 2. 1930. p. 297. . 334 18--Chapter Sound Control sound insulation may be obtained with a mounting which functions far above the fundamental forced frequency. For example, a compressor operating at 500 rpm has a forced frequency of 8.3 vibrations per second. By designing a mounting haying a natural frequency of 20 to 25 vibrations per second, it is possible to isolate practically all of the noise. If a slab of insulating material be placed under the entire foundation of a machine, as is often done in practice, it may happen that the natural frequency of the machine on its elastic support will be nearly the same as the frequencies which are to be insulated, in which case the elastic support will be worse than nothing. In general, as Equation 4. shows, both m and c should be as large as possible if the vibrations of the machine are to be effectively insulated from the solid structure of the building. Further more, the machine should rest upon a rigid floor so that the elastic yielding of the floor is prevented from communicating the machinery vibrations to the solid structure of the building. The elastic support under the machine acts as a low-pass filter which passes all frequencies below about two times the natural frequency of the machine mounted on its elastic support, but presents all frequencies Vabove about ine from reaching the solid structure of the building. The principal influence of the internal-mechanical resistance r is. to limit the vibration at the resonant frequency. It is generally advisable, therefore, to use materials which have an appreciable internal resistance. . The values of c and r can be determined for any specimen of flexible material and, when known, can be used to determine the insulation value of any particular set-up. The value of c can be obtained by making static- measurements of the amount of displacement of the compressed support for each additional unit of the compressing force. If this be done for a specimen of the flexible material of a certain thickness and area of cross section, the compliance can be determined for any other thickness or area from the relation that c will be directly proportional to the thickness and inversely proportional to the area of the flexible support. When the' internal resistance r is not too large, it can be determined by observing the successive amplitudes of the free vibrations of a mass m which rests upon a specimen of the flexible material, and solving for r by the usual log- decrement method. Or, if the damping be so great that the free motion of m is non-oscillatory, r can be obtained from measurements on the experi mentally-determined resonance curve of the. forced vibrations of m, or from measurements of the rate of return of m when it is given an initial displacement. If the resistance of a certain specimen of material, as cork, felt, or rubber, has been determined by any of these methods, the resistance for any other thickness or area of the material can be determined approxi mately because the resistance will be inversely proportional to the thick ness and directly proportional to the area of cross-section of the flexible support. Thus, if the values of c and r for a flexible material be known, it is possible to calculate, by means of Equation 4, the amount of insu lation that will be obtained from the use of this material as a flexible support for a piece of equipment having a mass m. For the routine calculations in practice, r may be neglected with only a slight sacrifice 335 of andAmerican Society Heating Ventilating Engineers Guide, 1936 of accuracy. Table 4 gives the values of c and r for a number of commonlyused flexible materials. In general; there are two principal points to observe in the design of a flexible support for any piece of equipment, namely, the material should have a relatively large compliance and it should be loaded to nearly the Upper safe limit of loading. Several flexible metallic supports have recently been developed. ; Example 2. A machine weighing 1000 Ib-has a base area of 20 sq ft. Assume that the principal vibration of the machine has a frequency of 100 cycles per second (most machinery vibrations are less than 150 vibrations per second; and the assumed frequency of 100 is quite representative of typical machines). Suppose that a 1-in. slab of cork- board, weighing 1:10 lb per. board foot iberplaced between the machine and the.floor. The loading on the cork will then be only 50 lb per square foot, or slightly more than M lb per square inch. (It is assumed that the compliance c in centimeters per dyne for a specimen 1 in. thick arid 1 sq cm in cross-section is 0.25 X 10-6 and the resistance r in mechanical ohms is 0.15 X 10s.) '. The transmissibiUty, iscalculated in the following manrier:, ; . - Mass of machine in grams = 1000 X 454 = 4.54 X I05. : . Area of base in square centimeters = 20 X 144 X . ...... 2:54 X 2154 = 1.86 X 10*.' 1 .; : . Therefore, the compliance of the entire support, 1 in. thick and 20 sq.ft in cross section, is 0.25 X iO"" it . on v 0^34 X 10"10 cm per dyne, and the resistance of Table 4. Compliance and Resistance-Data for Typical Specimens of .; 1. .. Flexible Materials . ; The compliances and resistances given in (fie table are;for specimens1 in. thick . .. and 1 sq cm in cross-section. , -. . ; __' Material , Description op Material Approximate Upper Sape Loading in ' Poundspeb Square Inch.. Compliance c in ;. Centimeters per Dtnb' Resistance r in . Absolute Units Corkboard 1.10 lb per 12 ' board foot Corkboard 0.70 lb per 8 board foot Fiber Board . . 1.35 lb per 4 to 6 , board foot - - Fiber Hoard - Carbet linine : . 10 \ Fiber Board :. Insulating board Fiber Board Insulating 15 . board Fiber Board ' Insulating . 15 -. board Anti-Vibro-Block :5 . Sponge Rubber 25 lb per T to 3 cubic foot Soft India Rubber 55 lb per 3 to 6 ' . cubic foot ; Hairfelt 10 lb per . . 1 to 2 . . cubic foot 0i25 x lO'6 0:15 x 10 0.50 x 10-? 0.60 x 10- 0.25 x10s 1- - 0.50 x 10s . ' 0.40 x 10- 0.18 x 10- 0.16 x 10- 0.12 x 10r 0.60 x 10- . 1.5 x 10s 3.0x10- . 1.2x10- 1.5x10" 1' aFroiii Architectural Acoustics. by V. O. Knudsen, p. 278. 336 Chapter- 18--Sound Control the entire support is 0.15 X 10s X 1.86 X 10*-= 0.28 X 10s mechanical ohms (or absolute units). Therefore, . . .. < "V- (0.28 X 10s)2 4- 10" 4,c X 100 X (0.134)8 (0.28 + 10^ + (2, X. 100 X 4.54 X 10 - 2x x 1(ffx 0,134 )' = 0.93 Consequently, it is seen that the transmissibiUty is nearly equal to unity, and that the support therefore is not satisfactory for insulating 100 or fewer vibrations per second. If the amount of cork be reduced so that it is loaded to 10 lb per square inch", the total area of the supporting cork will be Only 100 sq in. or 645 sq cm: The compliance of the entire support will now be 6.25 X 107 X = 0.39 X.JOr! cm per dyne, and the resistance will be 0.15 X 10? X 645 = 0.97 X 107 mechanical ohms (or absolute units). Therefore . ... . , .. . .. . .......... . v-I 101S (0.97 X.107)7 44x* X 100 X (0.39)* (0.97 X 10')* + 2x X 100 X 4(54 X 10s 10s --Y 2% X 100 X 0.397 6.037 It is seen, therefore, that with the bearing surface on the cork reduced to 100 sq in. (that is, with the cork loaded to 10 lb per square inch), the transmissibiUty is reduced to 0.037, or the amplitude of vibration trans mitted to' the flpor will be only about 1/27 of what it would be if the machine were mounted directly upon the floor. These two numerical examples ..will serve to show; , not only the manner of making the calcu lations, but also the importance of selecting the,proper type and design of flexible supports for insulating" the . vibrations, of a machine from the rigid structure of a building. CONTROL OF NOISE TRANSMISSION THROUGH DUCTS The most troublesome sources of noise from ventilating and air con ditioning equipment, are fan and motor noises which are transmitted through the ducts. The reduction, in decibels, of noise transmitted . through a duct,, neglecting reflection from ends and bends, is proportional (1) directly to the length of. the duct, (2) directly to the perimeter of the duct, (3) inversely to the area of cross-section of the duct, and (4) directly, (or at least approximately so) to the coefficient of sound absorption of the material which comprises the interior surface of the- duct.. It is apparent therefore, that^dong, narrow ducts, lined with highly absorptive material, will provide a high degree of insulation against the "transmission of noise through ducts. In fact,-small ducts (4 in. x 6 iii.), made of material having a.coefficient of sound-absorption' of. 0.50, will provide a noise reduction of slightly more than 1 db per linear foot.. , " . As can be seen from an inspection of. Table 2, noises of low frequency are difficult to absorb; on the other hand,"these frequencies are easily reflected by elbows, branches, arid duct ends whereas higher frequencies are little affected. Furthermore, the reflection effects are more pro nounced in small ducts than in large ducts. Hence, by introducing into a duct a sufficient length of small, absorptive channels together with a number of elbows or other; reflecting elements it is possible to -reduce the 337 of andAmerican Society Heating Ventilating Engineers Guide, 1936 transmitted noise to any required degree. This applies not only to ducts between the equipment room and other rooms in a building, but also to ducts connecting adjacent or nearly adjacent rooms. By the proper use of such filters it is possible to eliminate all of the difficulties which arise in connection with the transmission of sound through ventilating ducts. The problem is an engineering one which can be worked out prior to the in stalling of the equipment, and it can be calculated in such a way as to meet the most rigorous demands for-silent operation. There is a need for quantitative data regarding the attenuation or noise-reduction provided by different types of ducts,, but even with the meager data available it is possible to design filters which will suppress the ordinary noises incident to the ventilating or air conditioning of buildings4. In general, the motion of air resulting from the ventilating of rooms is not sufficient to introduce any appreciable difficulty in auditoriums, except where noise may originate from the issuing of high-speed air from nozzles. However, by proper stream-lining of the nozzles, it is possible to work with speeds which are adequate for all practical purposes without pro ducing any disturbing noises. Since sound is propagated with a velocity of more than 1100 fps, the velocity of the air would have to attain speeds of at least 20 to 30 fps before these wind velocities would have any appreciable influence upon the propagation of sound. ' If there is to be any appreciable motion of air in an auditorium, it is advantageous to have the upper layers of air moving in a direction from the stage toward the audience, as this will tend to refract the sound waves down toward the audience. However, unless the speed of the air is as great as 20 or 30 fps, the amount of refraction will not be noticeable. Therefore, as a rule the motion of air in an auditorium does not have an appreciable effect upon the acoustical properties of the room. EFFECT OF HUMIDITY UPON ACOUSTICS " Recent experiments6 have shown that both the humidity and the tem perature of air have a marked influence upon the rate of absorption of high-pitched sounds. Perfectly dry air is more absorptive than air con taining any amount of water vapor. At relative humidities of 5. to 25 per cent, the air is. highly absorptive but becoriies less and less absorptive as the humidity is increased. High-frequency sounds are propagated better in cold humid air'than in hot dry.air, and since high-frequency sounds are particularly important for. the preservation of good quality in speech arid music it is advantageous to maintain the air iri a room at a relatively high humidity, not less than about 55 to 60 per cent. On the other hand, where it is desirable to absorb all frequency components of sound, as for the reduction of noise in offices, it is advantageous to main tain relatively, dry air. .' The time of reverberation in a room is given by the following equation: . .V ; .; . ... ____ 0.049V ____ . AmV - 6'loge (1 - a) . ` (5y K1 r, 4How. Sound'is Controlled,: by V. -O. K,nudsen (Heating, Piping and Air Conditioning, October, 1931).. . sEffect of Humidity upon the Absorption of Sound in a. Room, by V. O. Knudsen (Journal Acoustical Society of America, JulJrV1931). ` Also see report presented at the May, 1933. meeting of A. S. of A. 338 Chapter 18--Sound Control where V = volume of room in cubic feet. . 5 = interior surface of room. a = average coefficient of sound-absorption of the interior surface of the room. m = the absorption coefficient of the air in the Tooth. . The coefficient m depends, upon the frequency of the sound and the humidity (and probably the temperature) of the air. At a temperature of 70 F, and for sound waves having a frequency of 4096 vibrations per second, m = 0.0027 at 25 per cent relative humidity, 0.0018 at 54 per cent, and 0.0013 at 82 per cent. It will be seen, therefore, that the absorp tion of sound in the air is twice as great at a relative humidity of 25 per cent as it is at a relative humidity of 82 per cent. This explains why sounds in the open travel so much better on humid days than they do on dry days. Although this dependence of absorption upon humidity is characteristic of low-frequency as well as high-frequency sound, the actual amount of absorption in the air is negligible for frequencies below about 1024 vibrations per second. However, the absorption of the higher frequencies in the air is a significant factor, and its dependence upon humidity, calls for careful consideration in planning the air-conditioning equipment for buildings. ... PROBLEMS IN PRACTICE 1 What are the characteristics of a good duct lining material for the absorp tion of sound? . A good duct lining should have the following characteristics: (1) high absorption qualities, (2) proper physical strength, (3) fire resistant, (4) clean with an absence of loose fibers or pieces, (5) smooth surface to reduce air friction, and (6) simple and easy application to existing or new installations. 2 Why do modern improvements in the acoustics and air conditioning of buildings present new acoustical .problems to the heating and ventilating engineer? . . .. -. ... ... - . .. . *- In acoustically treated rooms, both outside and inside noise are reduced, and conse quently the noise of. ventilating equipment becomes more noticeable. The closed windows in air conditioned buildings exclude outside noise, which makes all inside noise from mechanical equipment seem louder. 3 Name the acoustical problems which should be solved in connection with the installation of heating or air conditioning equipment. .. , Selection of quietly operating equipment;.adequate insulation of walls surrounding the equipment room; mounting of all vibrating equipment bn flexible supports which will eliminate solid-borne vibrations; design of suitable sound-filters to reduce-the trans mission of noise through ventilating ducts; the use of suitably low air speeds' and stream lining, where necessary, to prevent eddy noises. -. :. 4 Are good heat insulators also good sound insulators? . .. . , . As a rule, no. Blankets and felted materials offer considerable insulation' for sounds of high frequency, but very little for sounds of low frequency. 5 What is the principal consideration in the selection of elastic supports for the insulation of machinery vibration? ' :1 339 . American Society of Heating and Ventilating Engineers Guide, 1936 The support should be so compliant that the natural frequencyof the massof the machinery on its elastic support will be low in comparison with the vibrational frequencies which are to be insulated. 6 What means should he' utilized Tor'preventing air-borne noise from the ventilating equipment from being transmitted through,the walls, ceiling, or floor of the equipment room? . Treat the interior walls and ceiling of the equipment room with absorptive material; see that all doors and windows to the equipment room fit tightly in their frames; and use wall, and floor and ceiling partitions which have an insulation value of not less than 50 db. 7 Name effective methods for reducing the transmission of sound through ventilating ducts. ' .' . Line the ducts with sound, absorptive material, or use suitable sound filters made up of long channels of small cross-sectional area, lined with sound absorptive materiaL . . 8# What are the effects of humidity and temperature on the absorption of sound' in air? " ' ., . ... The absorption increases with a rise in temperature, and decreases for relative humidities above about 20 per cent. A relative humidity of 55 to 60 per cent is advantageous acoustically in large auditoriums. .. ; 9 How may sound be measured and what are the advantages of the methods available? . Three practical methods are now available to the heating and ventilating engineer, namely: . . . . -. .-. .. ; . a. The noise meter method. b. The audiometer and ear method. . ' c. The tuning fork and ear method. . . : . . ' Except for instrument adjustments and the'use of the eye in reading a meter, the human- element does not enter into measurements made with the noise meter, so it is to be pre-; ferred, if available. The tuning fork method is relatively cheap and simple and suf ficiently accurate for most field work. The audiometer and ear method ranks between these two in preference. . .. 10 What are some of the more important sources of noise in buildings, for which the heating and ventilating engineer may be held responsible? a. Furnace room equipment. '; .: b.. Radiators and piping. . 1. ' c. Uncalked openings in walls around pipes and ducts. - ! - . . . d. Ventilating fans, if noisy in operation and not isolated from the building structure by properly designed vibration damping foundations. , . e. High air velocity in. ducts.. .. .' /. Ventilation fan rooms not insulated acoustically from parts of the building where noise would be objectionable. ' " " , g. Ventilating ducts without flexible non-metallic sleeves in them; to break metallic sound conducting paths. , . . h. Cross connection .of rooms acoustically through ducts.. . ': . Ventilating ducts without sound absorbing lining, if required. : j. Unit heaters and ventilators. . : k. Unit air conditioners. .... . . , ; .... : . ~ 11 The noise level in the fan room directly under the main floor of a theater is.70 db. The floor is constructed as described in Item 5, Table 3. . What is "the fan noise level in the theater? . ... . . ,. , 340 18Chapter --Sound Control > y . :.. .: i` According to Table 3, the average coefficient of sound transmission, f, of such a floor construction is 0.0000020. The transmission Joss through the .floor, expressed in db, is; io iogl0 y y. .? : :i =,1? logl 0.0000020 1 .. ' --57 ' The fan noise level in the theater would, therefore, be 70 db less 57 db, or 13 db, which, according to Table 1, is an acceptable level. Another way of arriving at.the.same result is by use of Formula 3, in which./1 is the in tensity of fan noise as measured in the theater, and /" its intensity as measured in the fan room, /0 being the reference intensity in both cases, while x is 0.000002 or 2 X 10-6. . . /" ., ' y- 107 . '. . ; -y- .= 107 X 2 X 10- - 20 . Noise level -- lO lpgio 20 = 13 db. V y i; 12 Mieasiiirements made.separately of tbe noises from different sources pre vailing in a large, noisy banking room revealed the following average noise levels: ' a. From the street through windows, doors, and walls, 40 db. b. From adding machines, typewriters, human movements and conver sation, 60 db. ' c. From the ventilating system, 50 db. What was the total noise level of the room? Calling 7s, 7b, and 7V the intensities of the street, banking room, and ventilation noises, respectively, and 70 the reference level, we have: ~ = 10* -*o /b. = 10 /o The total intensity, /, will be /8 + /b + /v /v Io 10s The intensity level is 10 logio r 1o (/s + /b. + /v) = 10 logio /o = 10 logio (lCfl + 106 -I- 10s) = 60.4 db Note that the total loudness level is not much above the level of the loudest noise. While noise intensities may be added arithmetically, noise levels expressed in decibels cannot be so added. 13 I A ventilating fan room 30 ft by 30 ft by 12 ft has brick walls, a concrete floor, and a concrete ceiling. How much will the noise level of this room, expressed in decibels, be reduced by applying sound insulating material (co efficient of absorption 0.6 at 512 cycles) to two walls and the ceiling? Use Formula 2; . PS' / = ---- before applying material PS' /i = , after applying material . . . ' PS^ .. I a a' 7T " _P&_ ~ a . '' a' . . .. 341, 1 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Referring to Table 2: ' a = (4 X 12 X 30 X 0.031) + (2 X 30 X 30 X 0.016) = 73.4 a' = (2 X 12 X 30 X 0:031) + (30 X 30 X 0.016) + (2 X 12 X 30 X 0.6) + (30 X 30 X 0.6) = 1008.7 / o' . 1008.7 _ ,, - I, " a 73.4 13-7 Noise level reduction = 10 logu. -jj- = 10 Iogio 13.7 = 11.4 db. 14 What relation does the movement for the suppression of noise bear to the trend toward air conditioning of offices and other places in cities where people work or congregate? . Very important sources of disturbing sounds are the various street noises that gain entrance, not only through open windows but to a certain extent even through closed windows. If windows are to be kept dosed to exclude noise, air conditioning is a practical necessity, especially ` in summertime. Summertime air conditioning makes use. of awnings, which are not only desirable but economical in that they keep down cooling loads. To obviate condensation and frost on windows, wintertime air conditioning calls for storm sash or double glazing which in turn reduces the transmission of street noises. \ 342 Chapter 19 AIR DISTRIBUTION Opening Characteristics, Residences, Stores and Offices, Auditoriums, Railroad Cars TO produce proper air distribution in an enclosed space to be venti lated, heated, or cooled by air, the design and location of the air inlet and exhaust openings must be carefully considered. A system may fail, though it handles the proper amount of air at the required temperature, if such important design principles of air distribution are ignored.. Since air temperature and quantity are now moderately easy to control and vary, air distribution becomes the prime factor, particularly when comfort air conditioning is involved. ' ;) Owing to the lack of practical and satisfactory instruments for measur ing accurately air movement all air distribution information available may be justly criticized, but for practical design purposes this infor mation is sufficiently accurate. >, OPENING CHARACTERISTICS Any temperature differential between an occupied space air and inlet air causes the air to rise or fall a given vertical distance in a given time. This vertical rise or fall of the air stream can be moved horizontally by velocity, and if the mass of supply air is not diffused, the horizontal movement may be accomplished without changing the given vertical distance or the given time. This horizontal movement at a constant velocity may be reduced by expanding the air stream either by deflection, changing the dimensional ratio of the stream, or breaking the air into a series of streams in close proximity. With a few exceptions a high velocity should be used, with a large compact mass of air for a long air throw (Fig. 1), so that the periphery of the air stream will be reduced as much as is consistant with good practice. A grille used for a long air throw should have a large free area, and should have a number of fins, bars, or tubes with sufficient depth so that the width of each slot is approximately one-half the depth of the fins or bars. The grille opening should be as near square as possible and should' be expanded only slightly between the riser or duct and opening. When using grilles with a large free area, if the supply air makes an abrupt turn before being introduced into the occupied space, turning blades (Fig. 2) may be used to equalize the velocity and volume over the entire grille area and assist in controlling the direction of the air stream. 343 American Society of Heating and Ventilating Engineers Guide, 1936 19 -Chapter Air Distribution duced as far above, the floor line as possible, allowing 12 in. or; more between the top of grille and the ceiling'.for air, diffusion at this point so that the incoming air . will become- tempered before dropping-into the occupied;zone. -The supply air should not.be directed:against the ceiling or wall except as the restrictions of'the problem limit: the proper applica- . . . . Fig. 1. High Velocity. Long Throw Inlet Openings . For a short air throw, :and when the opposing wall is a: short distance from the inlet opening, the average velocity should be high,: with: the i> periphery of the air stream increased as: much as possible to increase the ^ scrubbing action between the incoming air stream and the stationary air. This causes turbulence or air mixing and readily reduces the vertical;rise or fall of-the air-by equalizing the temperature differential. This method of air introduction may be accomplished by, several satisfactory methods; It allows the use of a grille larger than the duct, even though the; grille has :a iarge open or free area, providing the dimensional-ratio (Fig. 3) is high .,. enough to increase the periphery of the air stream. With the same general type of grille this same, result is obtained by expanding the air stream. (Fig. 3) as it leaves the opening. The oldest method for reducing the pro jection of the air stream is by the use of stream turbulence. Introducing heated air with a simple inlet opening located in or near the floor- is satisfactory for low air velocities and volumes', but- for high air velocities / and volumes larger openings are desirable. Cooled air should be intro-/ Fig. 3. Perspectives and Gross Sections of High Velocity' : - Short Throw Inlet Openings' ' . tion, because, even though the striking of the air.breaks the stream and assists in . reducing the effect of temperature differential, it eventually spots and discolors the ceiling or wall area. ' , .1 . . - . RESIDENCES ' : With gravity warm air systems the inlet openings are usually located in the floor or base board of each room and the, exhaust openings in the floor near the exposed walls. (See Chapter 24).,, ,;. ...... 344 345 of andAmerican Society Heating Ventilating Engineers Guide, 1936 With a mechanical warm air system the inlet openings may be located in the floor or base board with satisfactory results but may also be located above the breathing line, which is equally satisfactory when proper inlet velocities are used. (See Chapter 23). Wall openings located above the breathing line permit higher inlet velocities with reduced sizes of the openings, resulting in improved air distribution satisfactory for both heated and cooled air. For the best location of the high inlet opening, the opening should be arranged so that the air will flow parallel and in close proximity to an exposed wall. If a low.inlet opening is used for cooled air the temperature differential causes the cooled air to settle in the lower part of the occupied space, thereby causing too great a temperature differential between the floor and breathing level. Exhaust openings for mechanical warm air systems located in or near the floor on either the exposed or interior wall function satisfactorily. The wall selected for the location of this opening does not appear to be Chapter 19--Air Distribution teristic, it is advisable to use reliable grille engineering information for the proper selection. See Catalog Data Section. It is generally impossible to supply too many inlet or exhaust openings for any of these conditions. One exhaust opening should be supplied for each office whenever pos sible, using a long narrow opening so that the air will be drawn from as large an area as possible, although the location can be either under or opposite the supply openings. Suspended unit heaters and coolers are occasionally used in stores and offices and where a single unit is used, care should be exercised to insure that the air flow will diffuse properly. Where a multiple number of units are used it is advisable to locate the units so that the air streams all Fig. 4. Examples of Residence Air Distribution important, except when the room has a multiple number of exposures, or excessive glass, because the movement of the air above the opening and the vertical room air movement usually exceeds the horizontal move ment. Examples of both heated and cooled air residential distribution are given in Fig. 4. STORES AND OFFICES Air distribution for stores and offices is' frequently a difficult problem because of the limitations in building design and construction. With a duct distribution system it is advisable to locate the inlet opening in the side wall as high as possible so that the location will be applicable for cooling as well as for heating: ------- When an inlet opening is located near the ceiling on one of the walls, the velocity through the opening should be as high as possible so as to project the air stream. The air stream may be expanded by deflection for short throws in offices and across the width of narrow stores. If the length of the throw required should exceed 40 ft as in the case of inlet openings installed at one or both ends of a store, a long throw opening (Fig. 1) should be used with a multiple number of openings proportionately spaced in either or both ends. Since every grille has a different charac 346 Fig. 5. Installation Arrangement of Multiple Suspended Unit Heaters Fig. 6. Air Distribution with Ceiling Inlet Opening Fig. 7. Section Through Theatre - Showing Air Distribution with Cooled Air Fig. 8. Section Through Room Showing Air Distribution with Unit Ventilator circulate in the same direction (Fig. 5) or in such a manner as to distribute the air uniformly throughout the space. . Another method of air introduction is a ceiling outlet (Fig. 6) with the air discharged downward on a deflector which spreads the air in all directions at right angles to the opening. With such an opening, a foot square and properly designed with a 4 in. opening completely around the. outlet, the air may be discharged in an expanding circle with a low velocity for large and small volumes. AUDITORIUMS This type of building often presents the greatest problem in air distri bution, mainly because winter conditions require air cooling, and for summer comfort air conditioning large volumes of air are required. . 347 American Society of Heating and Ventilating Engineers Guide, 1936' For all such buildings the downward system (Fig. 7) offers the best distribution without draft if a sufficient number of exhaust openings are placed under the seats. This method discharges the cooled air so that it filters through and mixes with the layer of heated air rising from the occupants. . The upward supply system allows the cooled air to remain partially undisturbed in the lower area and thus the heated air from occupants is not distributed until it rises near the exhaust openings. Small theatres and similar buildings may be properly designed by, distributing the air across the width of the building. The inlet opening locations should be as high as possible, with high velocities and multiple return openings in the floor under the seats, for best results. Schools are often heated and cooled by unit ventilators. These units should be designed for high velocity and a deflection of approximately 40 deg from the vertical (Fig. 8), so that the air stream will not strike the ceiling and fall too rapidly, particularly when a large quantity of air is admitted from outdoors. : RAILROAD CARS Although the general variation in the size of a railroad car is slight the construction often;does not. allow the best arrangement for air distribu tion, and consequently several alternate designs have been used, (See Chapter 13). ; 348 19--Chapter Air Distribution This system is highly satisfactory if the volume is properly proportioned for the multiple openings. . .. Several center duct air distribution systems are used in connection with railroad car air distribution. One method consists of a continuous slot in the bottom of the duct to which is attached a flat plate so the air is deflected along the car ceiling. This is satisfactory from an air distribu tion stand point, but it is difficult to equalize the volume of air over the entire length of this slot. Two other center duct installations are shown in Fig. 9. One shows the air distributed from the side of the duct through, about 12 inlet openings which have a high dimensional ratio and an. expanding deflection. This method of distribution causes the air to deflect downward on the outside wall of the car with the result that many passengers raise objections to the drafts. The other method, shown in Fig. 9, is to use a standard square or circular ceiling outlet in the bottom of the duct which allows the inlet air to be discharged on a deflector plate, which distributes the air along the ceiling in a widening circle at right angles to the inlet opening. Since the velocity is very low, most of the air drops into the aisle of the car. . Recirculated air from a railroad car usually consists of from 60 to 75 per cent of the air supplied and is picked up in the passageway ceiling of the car^at one end. This results in all of the air being drawn across the floor of the car toward the exhaust opening. This opening should be large enough so that the velocity is not in .excess of 400 fpm, and arranged so as to eliminate objectional drafts near this opening. . ,; PROBLEMS IX PRACTICE 1 What are the essential differences between a high velocity long throw and short throw inlet grille opening?. ' ' Generally a high' velocity long throw grille is used where a large compact mass of air is projected with a reduction in the periphery of the air stream, whereas with a short throw grille design the periphery of the air stream is expanded as much as possible to increase the scrubbing action between the incoming air stream and the stationary air. 2 Vds the, conventional warm air system, employing floor or baseboard supply registers,'suitahle for heating and cooling? ' - . . Floor or baseboard supply registers are suitable for heating service because the natural tendency of warm air is to rise. They are not suitable for cooling because the natural tendency Of cool air is to stay near the floor and gradually work its way to the return registers, thus not cooling the air in the upper-part of the room. See Fig. 4;, 3 What type of air, distribution system is suitable for heating and cooling a home?,. . _ :.. - .. ... ..... .. . In order to provide satisfactory cooling without drafts it is necessary to discharge the air at relatively high velocity toward the ceiling from a high point, as shown in Fig. 4. the register is properly designed and the air capacity is limited to approximately. 400 cfm, the cool air will mix with the air in the room before it drops to the occupied zone. However, care must be taken that discharged air does not impinge on beams which would cause the cool air to be deflected downward. This arrangement is also satisfactory for heating. . ; sV . . , . 4 ^Why is the conventional low velocity side wall inlet' unsatisfactory for cooling purposes? 349: American Society of Heating and Ventilating Engineers Guide, 1936 With the conventional side wall inlet using velocities of 300 to 400 fpm the discharged air quickly loses its velocity and drops, causing drafts in the occupied zone. 5 What method of side wall introduction is satisfactory for cooling purposes with a 12-ft ceiling height? The methods shown in. Figs. 1 and 3 can satisfactorily circulate air as much as 10 to 15 F below room temperature, provided (1) each jet is limited, to 400 cfm, (2) the outlet velocity is high, (3) the air is directed toward but not striking the ceiling, and (4) there are no beams on the ceiling. In order to employ this method in a classroom it is usually necessary to have at least three inlets, but even with three inlets the cooling capacity is limited to that obtained by circulating air at 10 to 15 F below room temperature. 6 0 Should unit ventilators be considered as heating units or as cooling units? Experience has shown that approximately 75 per cent of the time a classroom is occupied the problem is one of cooling rather than one of heating. For this reason unit ventilators should be considered as cooling units. 7 What method of air distribution is usually employed with unit ventilators? Most unit ventilators employ a unique method of air distribution in which the air is discharged at a high velocity toward the ceiling. The air stream is usually inclined toward the room. ' . 8 How should a unit ventilator be located in a room that has ceiling beams? When there are ceiling beams the unit ventilator should be so located that the beams will be parallel with the direction of the air discharge in order that the beams will not deflect the air downward.. .. . .. .. 9 0 What is the minimum temperature at which unit ventilators can distribute air in a classroom without causing drafts? ' ' Some manufacturers recommend a minimum outlet temperature of 60 F. Others recom- " mend no limitation of the outlet temperature, providing the unit is properly located and installed. ' 10 What is the usual method of ventilating school auditoriums and gym nasiums when unit .ventilators are used in the classrooms? .. .,. . If unit ventilators are used in classrooms the usual method of ventilating the auditorium or gymnasium is to use one or more large units located above and on either side of the stage. . . . 11 What is the maximum amount of air which should be discharged from one point in a school auditorium or gymnasium? The maximum amount of air which should be discharged from-one point is 5000 cfm. This limitation applies whether the air is supplied by units or by a central'fan from a distant point. ... , . , . _: _ 1 .. . ,. . . _ 12 Are vents required in school classrooms, auditoriums, and gymnasiums? Many states require vents in school classrooms, auditoriums and gymnasiums. -Most engineers recommend them for central fan systems. Many engineers recommend the elimination of all vents when unit ventilators are used.' If vents are installed they should be provided with dampers in order that they may be throttled and with back draft dampers to prevent cool air from entering the building at night and during holidays.13 13 0 What type of system is generally used in large continuously operated theaters? ..... ... Most large continuously operated theaters are provided with complete downward systems of air distribution similar, to the one shown in Fig. 7. With this system a large number of inlet openings is provided, each of which discharges air in a thin horizontal stream at high velocity in order that the cool air will be mixed with the air in the theater before it reaches the patrons. . . 350 Chapter 20 AIR DUCT DESIGN Pressure Losses, Friction Losses, Friction Loss Chart, Proportioning the Losses, Sizes of Ducts, General Rulesy Procedure for Duct Design, Air Velocities, Proportioning the Size for Friction, Main Trunk Ducts with Branches for Public Buildings, Equal. Friction Method, Details of Duct Construction THE flow of air due to large pressure differences is most accurately stated by thermodynamic formulae for air-discharge under condi tions of adiabatic flow, but such formulae are complicated, and the .error occasioned by the assumption that the gas density remains constant . throughout the flow may be considered negligible when only such pressure ' differences are involved as occur in ordinary heating and ventilating practice.. ' ~ . In the development of the formulae, diagrams, and tables for the flow of air, use is made of the following basic equation for the flow of fluids: . /, If Hv be the velocity head in feet of a fluid, and the velocity, V, be expressed in feet per minute, the fundamental equation is .. ... F -- 60 ^2g ffv . ' The factor g is the acceleration due to gravity, or 32.16 ft per second per second. It is usual to express the head in inches of water for ventilating work and, since the heads are inversely proportional to the densities of the fluids, 0r therefore, Hv -- 624 ' Ay . d 12 Hv = 5.2 . . . : V = 1096.5 (1) where V = velocity in feet per minute. hv = velocity head or pressure in inches of water. d = weight of air in pounds per cubic foot. For standard air (70 F and 29.92 in. barometer) d = 0.07495 lb per cubic foot. Sub stituting this value in Equation 1: - ., - 4005 V17, ' .. <2> 351 American Society of Heating and Ventilating Engineers Guide, 1936 o D-LLUl II ill II IJ-II H M-[ HIM l-l hr I I II I I I. II I I I I I I I I I I K, , 0 so 1 tttt . . ISO ` Too - , SJO ' JOO '" Cinwl Uni Radius m -PrujccNT or Pipe. DiAutTciC. Fig. 1. Gurve Showing Loss of Pressure in Round Elbows ' - The drop in pressure in air distributing systems is due to. the dynamic losses and the friction losses. The friction losses are those due to the friction of the air against the sides of the duct. The dynamic losses are those!due: to the change in the difection or in the velocity of air flow, . Dynamic'Losses _ - . : Dynamic losses occur principally at the entrance to the piping, in the elbows, and wherever a change in velocity occurs. The entrance loss is the difference between the actual pressure required to produce flow and the pressure corresponding to the flow produced ; it may vary from 0:1 to Chapter 20---Air Duct. Design 0.5 times the velocity head. The pressure loss in elbows must also be allowed for in the design. It is customary to express dynamic losses in terms of the percentage of the velocity head; in other words, the per centage of that pressure corresponding to the average velocity in the duct which is expressed in terms of inches of water gage. Figs. 1 and 2 show the effect of changing the radius of elbows of square and rectangular section. These charts are based on tests of pipe elbows of ordinal good sheet metal construction. For example, a five-piece round pipe elbow having a centerline radius of One diameter has a loss of about 25 per cent of the velocity head. At a velocity of 2000 fpm the corresponding head is 0,25 in. water gage, and at this velocity the elbow just referred to would cause a pressure drop of 0.063 in. water gage, Experience has shown that good results may be obtained when the radius to the center of-the elbow is times the pipe diameter.; The pressure drop will then be approxi mately 17 per cent Of the velocity head for round ducts, and 9 per cent for. square ducts. Very little advantage is gained in-making elbows'with a radius of more than two diameters. ,' : 'j Friction Losses ' . \ ' ' / :. : Friction losses vary directly as the length of the duct, directly as the square of the velocity, and inversely as the diameter. Since length is a fixed quantity for any system, the factors subject to modification are the area and the velocity,-which determine the relation^between the first cost of the duct system and the cost of the power for overcoming friction-.' -; The friction between the moving air and pipe surface causes a loss of head which is numerically equal to the. pressure -required-to maintain a given velocity, and is expressed in the following modification of Fanning's formula: ... . -y.. ... - For round pipe and standard air (70 F and 29.92 in. barometer) > ;/;/ V; *V-/7jV-^:(?F05)2: (3) For-rectangular ducts , .- where ' .. ; ` /JL -- loss of head, inches of water. -.: (Ay V \2 4005 ) ~ ve'oc'ty head, inches of water. . V = velocity of air,, feet per minute. L '= length of pipe I D = diameter of pipe 1 all in feet. a, b = sides of rectangular duct J f = coefficient of friction. c =-p = length of pipe in diameters for one head loss. . (4) For all practical purposes C varies only with the nature of the pipe surface: C = 60 for perfectly smooth pipe;.= 55 forpipeasused in planning mill exhaust systems; = 50 for heating and ventilating ducts; = 45 for - . 353 ' "' " ' " " 1936American Society of Heating and Ventilating Engineers Guide, 354 20Chapter --Air Duct Design smooth and 40 for rough conduits of tile, brick or concrete. However, Fritzsche states (and numerous tests check very closely) that / varies inversely as the 2/7 power of the pipe diameter, and inversely as the 1/7 power of the velocity, or inversely as the 1/7 power of capacity, which is the same thing. Thus Formula 3 may be revised as follows, based upon a loss of one velocity head (at 2000 fpm) in a length equal to 60 diameters of 24-in. galvanized swedged pipe: hh = 11 CDtn (4OO5) The preceding formulae are based on standard air, and for other con ditions the friction varies directly as the air density and inversely (ap proximately) as the absolute temperature. The increase of friction due to increase of air viscosity with increased temperature is small and is generally neglected. Friction Loss Chart ' ' . ,,' Fig. 3 is a convenient chart for-determining the friction loss for various air quantities in ducts of different sizes. The general form of this chart is familiar, but it should be noted that it is corrected for changes in the coefficient of friction based on the rule that the coefficient of friction varies inversely as the 2/7 power of the diameter, and inversely as the 1/7 power of the velocity. ' Fig. 3 is based on a loss of one velocity head (at a velocity of 2000 fpm) in a length equal to 50 diameters of 24-in. round galvanized-iron duct of the usual construction. Although this chart is laid out for a value of C equivalent to 50, it may be used for other values of C by varying the friction inversely as this constant. For ex ample, if a rougher pipe is used with 40 as the value of C, the friction loss 50 as read from the chart should be multiplied by Example 1. Assume that it is desired to pass 10,000 cfm of air through 75 ft of 24-in. diameter pipe. Find 10,000 cfm on the right scale of Fig. 3 and move horizontally left 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 0.59 in.; then for 75 ft the friction will be 0.75 X'0.59 = 0.44 in. In a like man ner any two variables may be determined by the intersection of the lines representing the other two variables. Proportioning the Losses . .. Other losses of pressure occur at the entrance to the duct, through the heating units, and at the air washer. In ordinary practice in ventilation work it is usual to keep the sum of the duct losses % to and the loss through the heating units at less than of the static pressure. The remainder is then available for producing velocity. In the design of an ideal-duct system, all factors should be taken into consideration and the air velocities proportioned so that the resistance will be practically equal in all ducts regardless of length: DUCT SIZES The sizes of ducts and flues for gravity or mechanical circulation of air are usually based on the losses due to friction, and these losses must be. kept within the available pressure difference. This pressure difference in 355 D iam eter 06 Branch Pipe (1 to 20 Pe r C e n t C a p a c it y ) American Society of Heating and Ventilating Engineers Guide, 1936 - -... .;.e* - - ,, i*.\. cvoo t'- < to /Cipudco juao J3J 356 tf eo. Chapter 20--Air Duct Design mechanical ventilation is that derived from the fan, while in gravity ventilation the aspirating effect due to the temperature and height of the column of heated air causes the pressure difference. . General Rules The general rules to be followed in the design of a duct system are: 1. The air should be conveyed as directly as possible at reasonable velocities to obtain the results desired with greatest economy of power, material and space. 2. Sharp elbows and bends should be avoided. .. 3. The sides of all ducts or flues should be as nearly equal as possible. (In no case should the ratio between long and short sides be greater than 10 to 1.) Procedure for Duct Design . , The general procedure for designing.a duct system is 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 heat. 3. Divide the building into zones and proportion the volume of air necessary to supply the heat for each zone. . 4. Determine the size of each outlet, based on the volume as obtained in the preceding : paragraph, for the proper outlet velocity. . \ 5. Calculate the sizes of all main and branch ducts by either of the following two. methods: . :, . . !: . p a. Velocity, Method. Arbitrarily fix the velocity in the various sections, reducing the}, velocity from the point of leaving the fan to the point of discharge to the room.-In this case the pressure loss'of each section of. the duct is calculated separately and}' the total loss found by adding together the losses of the various sections. ,. b. Friction Pressure Loss Method. Proportion the duct for equal friction pressure,' loss per foot of length. ' . , : : : .. ..." . 6. Calculate the friction for the duct offering the greatest resistance, to the flow of air, which resistance represents the static pressure which must be maintained in the fan outlet or in the plenum space to insure distribution of air in'the duct system. The duct haying the greatest resistance will usually be that having the longest run, although not ; necessarily so. .... ,: \ ' . Air Velocities . . . .' ' ' ' . V ' ' . ' ' . The following velocities of- air are considered standard'for public buildings: ' .! 1. Through the outside air intakes, 1000 fpm. , . .- : p 2. Through connections to and from heating unit, 1000 to 12(K).fpm. 3. Through the main discharge duct, from 1200 to 1600 fpm.! ' . . . ' . :; . 4. In branch ducts, 600 to 1000, and in vertical flues, 400 to 800 fpm. ': 5. In registers or grilles, 200 to 400 fpm depending upon the size and location. If diffusers of proper design are used, 25 per cent higher air velocities are permissible. . These duct velocities may safely be increased 20 per cent if first-class construction is used to prevent any breathing, buckling, or vibration. High velocities at one point in the system neutralize the effect of proper design at all other points; hence the importance of splitters in .elbows and similar precautions. For industrial buildings noise, is seldom considered, and main duct velocities as high as 2800 or 3000 fpm may be used where conditions will permit. For department stores and similar buildings, 357 D iam eter o f ' B ranch Pipe F ig . 5. M a in a n d B r an c h P ip e s for E q u a l F r ic tio n per F oot of L eng th (20 to, 100 Pe r C e n t Ca p a c ity ) 1936American Society of Heating and Ventilating Engineers Guide, 358 I 20Chapter --Air Duct Design maximum velocities with good construction and design may be as high as 2000 or 2200 fpm in main ducts, with suitable reduction in branches and outlets. With these velocities first-class duct construction is essential. Proportioning the Size for Friction By means of Figs. 4 and 5 the diameter of branch pipes necessary to carry a given percentage of the total air in the main pipe and to maintain equal friction per foot of the length through the entire system may be determined. These charts, as well as Fig. 3, are based on the assumption that the coefficient of friction varies inversely as the 1/7 power of the capacity. . Example 8- Suppose a 60-in. main pipe is to be used, and it is desired to know the size of branch pipe required to carry 50 per cent of the total air in the main. Find 50 per cent at the left of the chart, move right to the 60-in. diagonal line and note directly above at the top of the chart that the branch pipe will be 46.5 in. in diameter. Where rectangular ducts are used it is frequently desirable to know the equivalent diameter of round pipe to carry the same capacity and have the same friction per foot of length. Tabled gives directly the circular equivalent of rectangular ducts for equal friction and capacity. To obtain the size of rectangular ducts for different capacities, but of the same friction per foot of length, first obtain the equivalent round pipe for equal friction. Thus, if a branch of sufficient size to carry 30 per cent of a 12 x 36-in. pipe is desired, it is found from Table 1 that the main is equivalent to a 22.2-in. diameter round pipe. From Fig. 5, 30 per cent of this is a pipe 14.3 in. in diameter, and referring again to Table 1, the rectangular equivalent branch is a 12 x 14-in., 10 x 17J-in., or any other desirable combination. Multiplying or dividing the length of each side of a pipe by a constant is the same as multiplying or dividing the equivalent round size by the same constant. Thus, if the circular equivalent of an 80 x 24-in. duct is required, it will be just twice that of a 40 x 12-in. duct, or 2 X 23.3 = 46.6 in. DUCTS FOR PUBLIC BUILDINGS A main duct with branches is generally used to convey tempered air for ventilation purposes only. In place of individual ducts, a compara tively large main duct supplies air by branches to the room or rooms. The velocities vary according to the nature of the installation and the degree of quietness required. At the start of the run a velocity as high as 2000 fpm may be used, but this is considered the maximum for public building work, and is reduced to from 400 to'800 fpm in the risers. This duct system may be designed so that the loss of pressure in the branches is equalized in a manner similar to that previously described. Equal Friction Method Examples. Fig. 6 shows a typical layout of an air distribution system which is applicable for ventilation of hotel dining rooms and offices. The volume of air in cubic feet per minute for the room is determined on the basis of the number of air changes per hour required. In the example shown, the room ventilated, is a hotel dining room 135 ft x 85 ft x 15 ft. A 7J^-minute air change (8 air changes per hour) is assumed for proper ventilation, giving 22,935 cfra as the air required. 22 935 The clear area of the fresh air inlet is based on a velocity of 1000 fpm or ' = 359 Nir^' American Society of Heating and Ventilating Engineers Guide, 1936 -X V r;~- Chapter 20---Air Duct Design "T T a b l e 1. C ir c u l a r : E q u iv a l e n t s of R e c ta n g u la r D ucts fo r E q u a l F r ic t io n -- (C ontinued) 360 -i American Society of Heating and Ventilating Engineers Guide, 1936 F ig . 6. T y p ic a l L ayo u t op A ir D is t r ib u t io n System Chapter 20--Air Duct Design 22.94 sq ft. If the air washer is provided with automatic humidity control, the tempering coil should raise the temperature of the entering air to 32 F. The washer with its auto matic control will then raise the temperature from 32 F to 42 F. If the washer is not provided with automatic humidity control, the tempering coil must raise the temperature of the entering air to at least 55 F to allow for some temperature drop in the washer due to evaporation. The reheating coil is selected to raise the temperature of the air from that leaving the air washer to 70 F. The air washer should have a maximum velocity of 500 fpm through the clear area, which, in this case, is 46 sq ft. For more detailed infor mation on tempering coil and air'washer control, see Chapters 14 and 23. ' Since the plan shows a moderately short run of main duct with no risers near the fan outlet, a fan should be selected which will have the required capacity of 22,935 cfm with a maximum velocity through the fan outlet of 1400 fpm. The outlet area, therefore, should be 16J sq ft. ' Table 2. Pipe Sizes for Example 3a Volume or Am (cm) 22,935 12,510 10,425 8,340 6,255 4,170 2,085 Peb Cent or Total . Volume Diameter or Pipe . (Inches) . 100.0 54.6 45.4 36.3 - 27.2 18.2 9.1 56 45 42 39 35 29^ . 23 Equivalent Size or Rectangular Duct ... (Inches) .. 60 x 44: 58x30 50 x 30 42 x 30 42x24 30x24 30 x 15 , .Velocity through diffusers (not shown) to be approximately 300 fpm. X, . "' The main pipe size should be selected to give a velocity equal to or less than the velocity at the fan outlet. Choosing a 56-in. pipe with a cross-sectional area of 17.1 sq ft, the velocity in the main pipe will be 1340 fpm. Using the friction pressure loss method this 56-in. main pipe will be taken as the basis of calculation. ' Fig. 6 shows the amount of air to be handled by each section of pipe. Expressing the volume handled by each section as a percentage of the total volume and using the charts. Figs. 4 and 5, the pipe sizes are as shown in Table 2. ' . The pressure at the outlets nearest the fan will be greater than at the pipes farther along the run so that the former will tend to deliver more than the calculated amount of air. To remedy this condition, volume regulating dampers should be located at the base of each riser and adjusted for proper distribution, At points where branches leave the main it may be advisable, depending upon the nature of the installation, to install adjustable splitters similar to that shown in Fig. 6 where the main duct divides into the 68 in. X 30 in. and 50 in. X 30 in. branches. The rectangular equivalents are selected from Table 1; the width to depth proportion will be determined by construction requirements and ease of fabrication. The calcu lation of the friction is as follows: The longest run from the fan outlet to diffuser is 150 ft 0 in.; 150 ft of 56-in. pipe is equivalent to------ =------------------------------------------------- ___________________________ 32.2 dia. Ac Two 45-in., 90-deg elbows (2 X ^ X 8.5)________________ ____ _________________ 13.7 dia. 5t> (Assume each elbow equivalent to 8.5 diameters of duct. Fig. 1.) oq ' Two 23-ih., 90-deg elbows (2 X OO X 8.5)'________ _________ __________ . 7.0 dia. Two 23-in., 90-deg elbows in riser (2 X ~X 30) 24.7 dia. 5o (Two bad elbows in riser, each equivalent to 30 diameters of duct). (Total diameter of 56-in. pipe.. 77.6 of andAmerican Society Heating Ventilating Engineers Guide, 1936 The velocity head corresponding to a velocity of 1340 fpm is j = 0,112 in. 77 6 . Taking 50 diameters as one head loss, then X 0.112 = 0.174 in. static loss in duct. Ou - . .. Where the connection pieces are made with long easy slopes and the general work manship is good, a regain in static pressure may be deducted from the foregoing pressure loss. This can be taken as approximately two-thirds the difference in velocity pressures at the fan outlet and the last run of pipe. The velocity in the riser is 667 fpm with a corresponding velocity pressure of 0.027 in. The fan outlet velocity is 1400 fpm with a corresponding velocity pressure of 0.122 in. The regain equals (0.122 -- 0.027) = 0.063 in. The net static pressure loss in the duct only is then: 0,174 in. - 0.063 in.............. ................................... ................ ........................,.............. 0.111 in. Other friction losses are as follows: (1) Fresh air intake 1000-fpm velocity (1} heads X 0.0625)0.094 in. (2) Tempering coil loss (from manufacturer's tables)0.100 in. (3) Air washer loss (from manufacturer's tables)___________________ ...------------------0.250 in. (4) Reheating coil loss (from manufacturer's tables)______________ _____________ 0.100 in. (5) Allowance for regulating dampers and diffusers............................. ....................... 0.100 in. Static pressure loss of system...............:.......................................................................0.755 in. The fan should be selected from the manufacturer's ratings which, according to the Standard Test Code for Disc and Propeller Fans, Centrifugal Fans and Blowers1, will deliver 22,935 cfm at a static pressure of 0.755 in. and which has an outlet area of 16H sq ft. . The method of design used in Example 3 is the equal friction method, described under the heading Procedure for Duct Design. This involves the arbitrary reduction of velocity from the fan outlet to the point of. discharge to the room, and the friction is calculated by adding the pressure losses of each section of duct. This method requires dampering in the risers. ' '". Example 4. Fig. 7 shows an exhaust system layout for exhausting from buildings of the same type as in Example 3. Assume the air requirements based on the number of air changes per hour to be 16,800 cfm. Using a velocity of 1400 fpm in the main duct at Table 3. Pipe Sizes for Example 4a ' ... ' Volume ' or Am . . ..(era) 16,800 ; 11,550 9,450 5,250 4,200 3,150 2,100 . T Per'Cent , ' Diameter or op Total Pipe Volume . . . .............(Inches) 100.0 , 68.8....... 56.2 31.3 25.0 18.8 . ' - 12.5 47 jzC / 38 / 31 / 28.5 25.3 21.6 . 'Equivalent Size or . . 'Rectangular Duct (Inches) .. . . 38 x 48 30x46 30 x 40 24x34 24 x 28 16x34 16x24 . aVelocity through intake grilles (not shown) to be approximately 400 fpm. *See Chapters 17 and 44. ` 364 Chapter 2U--^;Air Duct Design v.t: .r.:: the fan inlet, which is an average velocity for this type of system, the area of the main is 12 sq ft, which corresponds to a 47-in. pipe. * Referring to Example 3, and using the charts, Figs. 4 and 5, the pipe sizes are as indicated in Table 3. - All risers will require dampering as in Example 3. The calculation of the friction is as follows: ` The longest run from the intake grille to fan inlet is 100 ft. . (1) Duct friction 100 ft of 47-in. pipe _______ --............--__-....... 25.6 dia. Two 28H-in., 90-deg elbows in riser ^ ^ ^ X 30 ^.......... ............................. 36.4 dia. (Two bad elbows in riser each equivalent to 30 diameters of duct). - One 283^-in., 90-deg elbow in horizontal run ....... ............................ 5.2 dia. Total diameter of 47-in. pipe...... ...................... ......... ..................................... 67.2 dia. Velocity head corresponding to 1400 fpm is = 0.122 in. 67 2 X 0122 '' Taking 50 diameters as one head loss, then --:--1----- ........ ;...... ... .. .. 0.164 in. ' pO .. .. ` , (2) Intake loss from grille (1heads at a 400 fpm velocity,1 Yi X0.01).............. 0.015 in. (3) Static pressure required to produce one velocity head at 1400 fpm___ 0.122 in. .(4) Loss occasioned by step-up of velocity (0.20 X 0.122)......... ...... ....__ _.. 0,024 in. (This loss varies from 0.05 to 0.40 velocity head depending upon the nature of the change. ` r or average systems 0.20 velocity head is a close approximation.) . . ` ;. . i' Static pressure loss on inlet side................................ .................... ........................ 6.325 in. 365 American Society of Heating and Ventilating Engineers Guide, 1936 l*7~w f. ,.4. ' * -C l _i 4 SECTION `TOP SHEET, SIDE SHEET THESE CROSSBREAKS ><^ 'A-NREEVER ,ra SSHHOOWT N OH A PUN H ELEVATION REINFORCED CROSS SEAMS SEAMS BETWEEN ADJACENT PANELS OR PUIN CROSS SEAMS Fig. 9. Details of Seams t-- : k z h* a lXu Fig. 10. Method of Installing Heating Unit Fig. 11. Installation of Easement in Duct Around Obstruction Chapter 20--Air Duct Design To this must be added the resistance on the discharge side of the fan. A fan outlet velocity of approximately 1500 to 1600 fpm may be used. Assuming the fan outlet to be equivalent in area to a 45-in. pipe, the velocity is 1525 fpm. '' Loss on discharge (15 ft from fan outlet to discharge): 15 X 12 45 4 diameters of 45-in. pipe.' The velocity head corresponding to a velocity of 1525 fpm is 0.145 and the discharge- 0 145 X 4 . .1 side loss is ----^----- = 0.012 in. The total static pressure loss of the system is then: 0.012 + 0.325 = 0.337 in. The fan will be selected to handle 16,800 cfm at a static pressure of 0.337 in. and to have an outlet velocity of 1525 fpm. Outlet area 11 sq ft. Where there are one or more ducts with branches, the velocity of air in the ducts may be either chosen arbitrarily or calculated for friction losses. When arbitrary values are assigned, a certain amount of dampering should be provided for; this will be small when the method chosen permits a drop in velocity as the quantity of air is reduced. After the total air quantity and the size of fan are ascertained, the main duct is usually fixed eis being at least equal in area to the fan outlet, or perhaps 10 per cent greater. From this main pipe all others are propor tioned. For example, if the main duct is 30 in. in diameter, a branch, to carry 10 per cent of the total capacity should be 12.7 in. in diameter (see, Fig. 4) in order to have the same friction per foot of length, while one carrying one-half the total capacity of a 30-in. main with the same friction loss per foot would be 23.4 in. in diameter.! By this method of equalizing friction it is unnecessary to consider the resistance of each section of pipe independently, but only to know the distance from the fan outlet to the end of the longest run of pipe, the number and size of elbows, and the diameter and velocity in the largest pipe. Example 5. If the greatest length of piping in a system is 130 ft with a 26-in. diameter main pipe and one 20-in. elbow, the piping having been designed for equal friction per foot of length, the friction would be the same as for 130 linear feet of 26-in. pipe, or 60 diameters; To this should be added the friction loss in elbows, in this case one 20-in. elbow, which has a loss equivalent to 8.5 diameters of 20-in. pipe. This in tu rn is 20 k2so X 8.5 = 6.6 diameters of 26-in. pipe. The total equivalent length of the system will then be 60 -f- 6.6, or 66.6 diameters. Since 50 diameters is equivalent to one velocity head, the loss is = 1.33 times the velocity head. If the velocity is, for example, 2200 fpm, corresponding to 0.3-in. pressure, the friction loss of the system will be 1.33 X 0.3 = 0.399 in. ' Frequently the prevention of sound in a heating or ventilating system imposes more severe restrictions than the prevention of excessive pressure drop. This question is highly involved and requires consideration of cinany factors. The air velocities to be used will vary with the standard of construction used in the ducts themselves as well as with the nature of the occupancy and the construction of the building. In general, architects and engineers who leave the details of duct construction to the contractor must, of necessity, design for lower velocities than might be required for quiet operation if proper construction details were always followed. The 367 American Society of Heating and Ventilating Engineers Guide, 1936 contractor may be expected to build the ducts by the least expensive -methods, and the engineer must anticipate this.' For further information on noise reduction, see Chapter 18. : Details of Duct Construction If panel construction is used with standing seams or similar reinforce ment, and the; panels are cross-broken to give rigidity, there is less like lihood of vibration due to air flow, or deflection due to air pressure. Elbows made without splitters, and improperly shaped transformation sections produce high local velocities which are the cause of noise in duct work: The use of first-class duct construction with well-designed trans formation sections and splitters in elbows tends to maintain relatively uniform velocities with decrease in turbulence and in the noise produced. Table 4. Sheet Metal Gages for Rectangular Duct Construction1 Gaqb Width op Duct ''. ' Seam Reintoeced Seam 26 Up to 12 in. 24 13 in. to 30 in. i 22 31 in. to 48 in. i 22 49 in. to 60 in. 20 61 in. to 90 in. . }4 in. x 1 Yi in. in. x 1% in. If panels are not cross-broken two gages heavier material should be used. Figs. 8 to 12 show acceptable construction details for rectangular ducts, elbows, and transformation pieces or connections. Other methods are also acceptable, such as the use of angle iron stiffeners for large ducts. Good construction is essential to the elimination of duct noises and for the prevention of a flimsy installation. Fig. 8 is an isometric view of a duct showing the location of the stiffening seams on the top and side panels. The cross seams should not occur at the same place but should be staggered as indicated. Heating units should be installed as shown in Fig. 10 with the duct connections making an angle of not less than 45 deg, but preferably 60 deg. Fan dis- charge,connections should have a maximum' slope of 1 in 7, as indicated in Fig. 12. Whenever a pipe or other obstruction passes through a duct an easement should be placed around the pipe as indicated in Fig. 11. The recommended gages for rectangular sheet metal duct construction are given in Table. 4. . . : : .. REFERENCES Fan Engineering, Buffalo Forge Co. " . Heat Power Engineering by Barnard, Ellenwood, and Hirshfeld, Part III. ~1. . . ` ' Mechanical Engineers' Handbook by Lionel S. Marks, McGraw-Hill Book Go. ` ' The Flow of Liquids, by W. H. McAdams, Refrigerating Engineering, February, 1925, p. 279. -A Study.of the Data on the Flow of Fluids in Pipes, by Emory Kemler, AS.M.E. Transactions, Hy draulics Section, August, 31, 1933, p. 7. ' ; 368 i i j i Chapter 20--Air Duct Design PROBLEMS IN PRACTICE 1 Determine the equivalent number of diameters of straight pipe equivalent to a 90 deg elbow having center line radii of (a) 100 per cent, (b) 150 per cent, abd (c) 200 per cent of the pipe diameter. Assume 1 velocity head lost in 50 diameters. - From Fig. 1 the per cent of velocity head lost: a. For 100 per cent radius is 25.5 per cent X 50 = 12.8 diameters straight pipe. b. For 150 per cent radius is 17.0 per cent X 50 = 8:5 diameters straight pipe. c. For 200 per cent radius is 14.5 per cent X 50 = 7.3 diameters straight, pipe. . 2 Why is it desirable to make elbowswith a radius equal to one and one-half times the pipe diameter? Reference to Figs. 1 and 2 will show that while the loss of velocity head, as indicated by the curves, shows considerable variation for elbows between the range of 50 and 150 per cent radius, the line is practically straight after 150 per cent, indicating very little variation in loss of head for elbows of larger radius. ' 3 What is the best shape to use for ducts? . The shapes to be used in designing ducts, in the order of their preference, are round, square, and rectangular. ' ' 4 What determines which shape to use? Structural and space conditions. Because ducts are as a rule part of the building or structure, it is necessary to proportion their, sizes to fit the spaces available. 5 What is meant by "arbitrarily fix the velocity in the various sections?" When using the velocity method as a basis for design, the maximum allowable velocity is fixed for the main supply duct at the fan, and this velocity is gradually decreased as each branch or outlet is taken off the main supply duct. 6 Which system of duct design is to be preferred, the velocity method or the friction pressure loss method? The friction pressure loss method can be used to advantage where no structural or building conditions limit the shape of the ducts. Where these limiting conditions exist the velocity method is to be preferred. 7 Are the grille sizes figured on the same basis as the outlets? The free area through the grilles is figured the same as the outlets, and this area is increased from 20 to 50 per cent, depending on the, design of the grille, to allow for the loss of area caused by the construction of the face of the grille. 8 Where it is necessary to provide steel angle braces, how far apart should they be spaced? Angle braces for large ducts should be placed on 3-ft 0-in. centers. How much air will a 10-in. by 24-in. duct handle if it is part of a system designed on a pressure drop of 0.1 in. per 100 feet of run? , 1450 cfm (Table 1 and Fig. 3). . . ^ How does a splitter at a duct-junction influence the volume of the air going through each branch? American Society of Heating and Ventilating Engineers Guide, 1936 A splitter facing the direction of air flow cuts off the air and delivers the desired amount to the branch. , , ' i . ' 11 Why does a wide, shallow duct offer more resistance to the flow of air than does a square duct of equal cross-sectional area? The perimeter of the wide, flat duct is greater than that of the square-section duct, so the former has the greater frictional area which increases the resistance and thus reduces the volume at any given pressure; 12 What methods are used to keep large ducts from vibrating because of air pulsations, and from sagging because of. their own weight? External bracing, such as standing seams, or structural shapes, like tees or angles, should be placed across the top and bottom. Exterior braces or cross buckling of metal sheets in' diagonal panels may be used for the sides of large ducts. 13 What velocities of air flow should be used in the trunk ducts of a venti lating system in a public building? From 1200 to 1600 fpm. 14 In a ventilating system in a residence, what is the recommended air velocity through supply registers and grilles? 400 fpm. 370 Chapter 21 INDUSTRIAL EXHAUST SYSTEMS Classification of Systems, General Rules for Design, Suction and Velocity Requirements, Hoods, Design of Duct Systems, Collectors, Resistance of Systems, Efficiency of Exhaust Systems, Selection of Fans and Motors SOME type of exhaust and collecting system is necessary in almost every industry and the present chapter attempts to give general information relating to the design of factory exhaust systems in order that efficient and economical control of dusts and fumes may be achieved. CLASSIFICATION OF SYSTEMS There are two general arrangements,' the central and the group systems. In the central system a single or double fan is located near the center of the shop with a piping system radiating to the various machines to be served. In the group system, which is sometimes employed where the machines to be served are widely scattered, small individual exhaust fans are located at the center of the machine groups. The grpup arrangement has the advantage of flexibility. Exhaust systems are also classified by the means employed to collect dust or other material handled. The dust or refuse may be collected and controlled by enclosing hoods, open hoods, inward air leakage, or by exhausting the general air of the room. - With some classes of machinery it is not feasible to closely hood the machines 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. This class includes such machines as rubber mills, package filling machinery, sand blast, crushers, forges, pickling tanks, melting furnaces, and the unloading points of various types of conveyors. The 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. When the hood must be placed at some distance above the machine it should be large enough to encompass an area of considerable extent as diffusion is usually quite rapid. Consideration must also be given to the natural movement of the fumes. For those that are lighter than air the hood should be-over or above the machine and where a heavy vapor or dust-laden air at ordinary temperature is to be removed, horizontal or floor connections are required. If it is attempted to remove heavy dust such as lead oxides by an over head hood the conditions may be worse than if no exhaust were used at all, owing to the rising air current carrying the dust up through the 371 of andAmerican Society Heating Ventilating Engineers Guide", 1936 breathing zones. The objective to keep in mind in all cases is to take advantage of the natural tendency of the material to move upward or downward. " In another class of operation the main objective is to prevent the escape of dust into the surrounding atmosphere, the removal of some dust from the machine or enclosure being merely incidental. The dust-creating apparatus is enclosed within a housing which is made as tight as prac ticable, and sufficient suction is applied to the enclosure to maintain an inward air leakage, thus preventing escape of the dust. While the exhaust system is required to handle only the air which leaks in through the crevices and openings in the enclosure, yet in many installations leakages are very high and great care is required to obtain satisfactory results with a system of this kind. The inward-leakage principle is utilized for controlling dust in the operating of tumbling barrels, grinding, screening, elevating, and similar processes. . Certain dust and fume producing operations are best carried on by isolating the process in a separate compartment or room and then apply ing general ventilation to this space. The compartment or room in which the work is performed should be as small as is consistent with convenience in handling the work. The ventilating, system should be designed so that a strong current of clean air is drawn across the operator, and away from him toward the work, where the dust is picked up and carried from the room. - . ' ; GENERAL RULES FOR DESIGN The first step in the design of an exhaust system is to determine the number and size of the hoods and their connections^ No general rules, however, can be given since hood and duct dimensions are determined by the characteristics of the operations to which they are applied. When a tentative decision regarding the set-up has been made, it is then 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 avail able. Finally, in choosing the fan, the area of the intake should be equal to or greater, than the sum of the areas of the branch ducts. The speed, of course, must be sufficient to maintain .'the estimated suction and air velocities in the system! In general, the most important requirements of an efficient exhaust and collecting system ar^ as follows1: 1. Hoods, ducts, fans and collectors should be Of adequate size. 2. The air velocities should be sufficient to control and convey the materials collected. 3. The hoods and ducts should not 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 inflammable dusts and fumes are conveyed, the piping should be provided with an automatic damper in passing through a fire-wall. ' 6. Ducts and all metal parts should be grounded to reduce the danger of dust ex plosions by static electricity., ,, 7. The design of an exhaust system should afford easy access to -parts'for inspection and care. . .. lFor more detailed requirements see Safe Practice Pamphlets Nos. 32 and'37, published by the National Safety Council, Chicago. :........................... ................ ': 372 Chapter 21--Industrial Exhaust Systems SUCTION AND VELOCITY REQUIREMENTS The removal of dust or waste by means of an exhaust hood requires a movement of air at the point of origin sufficient to carry it to a col lecting system. The air velocities necessary to accomplish this depend upon the physical properties of the material to be eliminated and the Table 1. Size of Connections for Wood-Working Machinery Type op Machine Diameter op Connections in Inches Circular saws, 12-in. diam. ................................................. .. ................... .... ......... Circular saws, 12-24-in. diam... ...................... ;__,____ .... Circular raws, 24-40-in. diam.................. . Band saws, blade under 2 in. wide.......................................................................... Rand saws, blade 2-3 in. wide. ............................................... Rand saws, blade 3-4 in. wide.....................:.............................. Band saws, blade 4-5 in. wide....... ........... ......................... _.................. Band saws, blade 5-6 in. wide. ............. ....................................... . _ Single end tenoners.............................. .............. Double end tenoners__ :... Double end, double head tenoners.. . .............. ................ ......... .. . Planers, matchers, moulders, stickers, jointers, etc.-- With knives, 6-10 in.. .......... .......................................................... With knives, 10-20 in.. :____ _________________ 1 With knives, 20-30 in........................ Shapers, light work............................. ......... Belt sander, belt less than 6 in. wide. ......... ............... ;............ Belt sander, belt 6-10 in. wide . Belt sander, belt 10-14 in. wide Drum sander, 24 in.. .......... .......... .............................. .................. Drum sander, 30 in.. _ ...............................,......:....'.............. Drum sander, 36 in...................................... ;.................... Drum sander, 48 in........'.......... . Drum sander, over 48 in._........... .............................................. Disc sander, 24 in. diam................................. . Disc sander, 26-36 in. diam..................................... Disc sander,-36-48 in. diam.... .............................. Arm sander...... ............................................ ' . ' 4 5 '6 4 5 6 7 8 6 6 7 10 ' 5-6 6-8 6-10 4-5 8 5 6 .7 : .5 6 7 8 10 ,5 6 7 4- direction and speed with which it is thrown off. If the dust to be removed is already in motion, as is the case with high-speed grinding wheels, the hood should be installed in the path of the particles so that a minimum air volume may be used effectively.* It is always desirable to design and locate a hood so that the volume of air necessary to produce results is as small as possible. . The static suction at the throat of a hood is frequently used in practice as a measure of the effectiveness of control. This is of considerable value where exhaust systems adapted to particular operations have been standardized by practice. Tables 1 and 2 present the duct sizes usually employed for standard wood-working machinery and. for grinding and buffing wheels. Static pressures which in practice have been found necessary to control and convey various materials, are given in Table 3.: It must be remembered, however, that* the suction is merely a rough 373 ofAmerican Society Heating and Ventilating Engineers Guide, 1936 Table 2. Size of Connections for Grinding and Buffing Wheels Diameter op Wheels . Grinding-- 6 in. or less, not over 1 in. "thick._____ 7 10 in. in. to to 9 16 in., in., inclusive, " not " over " 1H 2 in. in. thiack___ 17 in. to 19 in., " * 3 in. a 20 in. to 24 in., " * " 4 in. a 25 in. to 30 in., " " 5 in. a Buffing-- . 6 in. or less, not over 1 in. thick._____ 7 in. to 12 in., inclusive, not over 1H in. thick___ 13 in. to 16 in., " " " 2 in. a . 17 in. to 20 in., 21 in. to 27 in., " " " " "3 "4 in. in. a a 27 in. to 33 in., " " " 5 in. a Max. Grinding Surface Sq In. 19 43 101 180 302 472 19 57 101 189 338 518 Min. Diam. of Branch Pipes in Inches 3. m 4 AH 5 6 3H 4 AH 5 6 7 measure of the air volume handled and consequently of the air velocity at the opening of the hood. The elimination of any dusty condition requires added information concerning the shape, size and location of the hood used with regard to the operation in question. In some states grinding, polishing and buffing wheels are subject to regulation by codes. The static suction requirements, which range from to 5 in. water displacement in a Z7-tube, should be followed although in several instances they may appear to be excessive. Frequently, in these 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 counteracting useful inward draft. This tendency may be diminished by locating the connecting duct so as to create an air flow of not less than 200 fpm about the lower rim of the wheel. Exact determinations of hood control velocities are not available, but it is safe to assume that for most dusty operations they should-not be less Table 3. Suction Pressures Required at Hoods ' orTtfb Installation - ' . \ . Static Suction in - or 'Inches Wateb Exhausting from grinding and buffing wheels.. ........................................ Exhausting from wood-working machinery--light duty. _ ................... Exhausting from rubber manufacturing processes.................................... Exhausting from pottery processes.................._............................................. Lead dust and fume exhaust- ............................ 1....................................... Fur and felt machinery exhaust.... ................... - ................ ......................... l>f-5 22 2-4' 2-3 2 2 2 2-4 2-3 2-3 2 3-5 / 374 .3 Chapter 21--Industrial Exhaust Systems than 200 fpm at the point of origin. For granite dust generated by pneumatic devices, Hatch et al2 give velocities from 150 to 200 fpm, depending on the type of hood used, as sufficient for safe control. Con sidering the character of the industry, air velocities of this order may be extended to similar dusty operations. The method for approximately determining these velocities in terms of the velocity at the hood opening is given below. HOODS 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 dusts and articles dropped by the operator. Such provisions are of assistance in keeping the ducts clear. Air volumes used to control many dust discharges may often be reduced by effective baffling or partial enclosure of an operation. This procedure is strongly urged where dusts are directed beyond the zone of influence of the hood. '. Axial Velocity Formula for Hoods When the normal flow of air into a hood is unobstructed, the following formula may be used to determine the air velocity at any point along the axis8: . Y - 01 <? Xs + 0.1 A (!) where V = velocity at point, feet per minute. A = area of opening, square feet. x = distance along axis, feet. Q = volume of air bandied, cubic feet per minute. Velocity Contours . It is possible by use of a specially constructed pitot-tube4 to map contours of equal velocity in any axial plane located in the field of in fluence. It has been found that the positions of these contours for any hood can be expressed as percentages of the velocity at the hood opening and are purely functions of the shape of the hood5. 'Hatch, Theodore, Drinker, Philip, and Choate. Sarah P.t Control of the Silicosia Hazard in the Hard Rock Industries. I. A Laboratory Study of the Design of Dust Control Systems for Use with Pneumatic Granite Cutting Tools. CJournal of Industrial Hygiene, VoL XII, No. 3, -March, 1930). The Control of Industrial Dust, by J. M. DallaValle (Mechanical Engineering, Vol. 5, No. 10, October, 1933). Studies in the Design of Local Exhaust Hoods, by J. M. DallaValle and Theodore Hatch (Transactions A.S.M.E., Vol. 64, 1932). Velocity Characteristics of Hoods under Suction, by J. M. DallaValle (A.S.H.V.E. Transactions, Vol. 38, 1932). . 375 andAmerican Society 0/Heating Ventilating Engineers Guide, 1936 Further, the velocity contours, are identical for similar hood shapes when the hoods are reduced to the same basis of comparison. These facts 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 with a side ratio of one-half. The distribu tion shown is identical for all openings with a similar side ratio provided the mapping is as shown in the figure. The contours, of course, are expressed as percentages of the velocity at the opening. Velocity at the Opening ' Air Flow from Static Readings '> 1 : _ The volume of air flow through any hood may be determined from the following equation: :1 where Q = 4005 / a \A*r Q = volume of. air flow, cubic feet per minute: '! .. . :\ o area of connecting.duct, square-feet:.................... . .. . - At =?.static suction at throat of hood, inches of water. , . /. sf orifice or restriction coefficient which varies from 0.6 to 0.9 depending qn the shape of the hood................. .......................... Chapter 21--Industrial Exhaust Systems An average value of/is 0.71, although for a well-shaped opening a value of 0.8 may be used. The factor/ is determined from the equation: '"V-JT where hv is the velocity head in the connecting duct. The term 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 respect to the hood are known. This is clearly indicated by Equation 1 which shows that the velocity at any point along the axis varies inversely as the area of the opening and the square of the distance. However, this formula coupled with Equation 2 should serve to indicate the velocity conditions to be expected when operations are conducted external to the hood opening. Large Open Hoods . Large hoods, such as are used for electroplating and pickling tanks, should be subdivided so the area of the connecting duct is not less than one-fifteenth of the open area of the hood. Frequently, it will be found necessary to branch the main duct in order to obtain a uniform distri bution of flow. Canopy hoods should extend 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 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. Cross drafts from open doors or windows disturb the rise of the vapors and therefore provision must be made for them. The air velocities required also depend upon the character of the vapors given off, cyanide fumes, for example, requiring an air velocity of approxi mately 75 fpm on the surface of the tank and acid and steam vapors requiring velocities as low as 25 to 50 fpm. The total volume of air flow necessary to obtain these velocities may be approximately determined from the following simple formula: where Q = l.iPDV (4) - Q = total volume of air handled by hood, cfm. P -- perimeter of the tank, feet. : .- . D = distance between tank and hood opening, feet. V = air velocity desired along edges and surface of tank, fpm. - Lateral Exhaust Systems The lateral exhaust method, as developed for chromium plating6, is applicable in many instances in preference to the canopy type hoods. . The method makes use of drawing air and fumes laterally across the top of vats or tanks into slotted ducts at the top and extending fully along one or more sides of the tanks. The slots are 2;ih. wide and for effective eSee Health Hazards in Chromium Plating, by Bloomfield,;J. J., and. Blum, Wm. (U. S. Public Health Report, Vol. 43, No. 26, September 7. 1928). . ... ... . . . ... 377 American Society of Heating and Ventilating Engineers Guide, 1936 ventilation a 2,000 fpm exhaust air velocity at the slot face is advisable. In addition, the duct should not be required'to draw the air laterally for a distance of more than 18 in. and the level of the solution should be kept 6 to 8 in. below the top of the tanks. Flexible Exhaust Systems The flexible exhaust tube method may be advantageously used for removing dust or fumes. Flexible tubes having one end connected to an exhaust system and a slotted hood attached to the other end may be shaped at will to fit in with industrial processes without affecting the ease of operation. Efficient-dust or fume removal may be had with use of relatively small exhaust volumes. This type of system may be used on swing grinders, portable grinding wheels, soldering operations, stone cutting, rock drilling, etc. 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 performed mechanically in wholly enclosed booths, the volatile vapors may reach injurious or explosive concentrations. At all times the con centrations of these vapors, and particularly those containing benzol, should be kept below 100 parts per million. Spray booth vapors are dangerous to the health of the worker and care should be taken to mini mize exposure to them. ' It is recommended in the design of spray booths that the.exhaust duct be located in a horizontal position slightly below the object sprayed. Stagnant regions within the booth should be carefully avoided or should be provided with exhaust. The air volume should be sufficient to main tain a velocity of 150 to 200 fpm over the open area of the booth, and the vapors may be discharged through a suitable stack to permit dilution, but it is better practice to pass the fumes or vapors through baffle type washers or scrubbers designed fpr efficient spray fume removal7. 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 installation of chemical equipment and should be well lighted. Air velocities should exceed 50 fpm when the window is opened to its maxi mum height. DUCT SYSTEM DESIGN The duct system should be large enough to transport the fumes or material without causing serious obstruction to the air flow. It is good practice to proportion the ducts to obtain the desired velocities and suction pressures at the hoods, although in many cases only an approxi mation to ah ideal design is possible. Many exhaust hoods, and par fFor a discussion of spray booths, see Special Bulletin No. 16, Spray Painting in Pennsylvania. Depart ment of Labor and Industry. 1926, Harrisburg, Pa. v- 21Chapter --Industrial Exhaust Systems ticularly those used in buffing and polishing, are connected by short branch pipes to the main duct which renders proportioning impractical. Construction The ducts leading from the hoods to the exhaust fan should be con structed of sheet metal not lighter than is shown in Table 4. The piping should be free from dents, fins and projections on which refuse might catch. All permanent circular joints should be lap-jointed, riveted and sol dered, and all longitudinal joints either grooved and locked or riveted and soldered. Circular laps should be in the direction of the flow, and piping installed out-of-doors should not have the longitudinal laps at the bottom. Every change in pipe size should be made with an eccentric taper flat on the bottom, the taper to be at least 5 in. long for each inch change in diameter. All pipes passing through roofs should be equipped with collars so arranged as to prevent water leaking into the building. The main trunks and branch pipes should be as short and straight as possible, strongly supported, and with the dead ends capped to permit inspection and cleaning. All branch pipes should join the main at an Table 4. Gage of Sheet Metal to be Used for Various Duct Diameters DuHETta or Doct Gaos or Metal 24 22 20 18 acute angle, the junction being at the side or top and never at the bottom of the main. Branch pipes should not join the main pipes at points where the material from one branch would tend to enter the branch on the opposite side of the main. 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. Elbows should be made at least two gages heavier than straight pipe of the same diameter, the better to enable them to withstand the addi tional wear , caused by changing the direction of flow. They should pref erably have a throat radius of at least one and one-half times.the diameter of the pipe. 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 sweep-up connections should be so arranged that foreign material cannot be easily introduced into them. 379 American Society of Heating and Ventilating Engineers Guide, 1936 21,--Chapter Industrial Exhaust Systems Table 5. Air Speeds in Ducts Necessary to Convey Various Materials Table 6. Loss Through 90-Deg Elbows Material . Am Velocities (fpm) Elbow Center Line Radius in Per Cent . of Pipe Diameter . Loss in Per Cent of Velocity Head Grain dust '. . Wood chips and shavings....... .................................................................. ......... ........... Sawdust.................... ,.......... .......... Jute dust______ _________ ________________________ _______ Rubber dust.______________________ :_____________________ Lint...... ............ .......... Metal dust (grindings). . ________ Lead dusts Brass turnings (fine).............:.................................................... .............. Fine coal 2000 \ 3000 2000 2000 2000 1500 2200 5000 4000 4000 50 100 150 200 to 300 . 75 26 17 . 14 Hence, the duct velocity must be increased either by speeding up the fan or decreasing the diameter of the duct, or both. Duct Resistance . At the point of entrance of a branch pipe with 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 per cent. While this is not always necessary and is frequently done at the expense of a reduced air velocity, it is none the less advisable where future expansion of the exhaust system is contemplated. The resistance to flow in any galvanized duct riveted and soldered at the joints may be obtained from Fig. 3, Chapter 20. The pressure drop through elbows depends upon the radius of the bend. For elbows whose centerline radii vary from 50 to 300 per cent of pipe diameter, the loss may be estimated from Table 6. It is sometimes convenient to express the resistance of an elbow in terms of an equivalent length of duct of the same diameter. Thus With a throat radius equal to the pipe diameter the Air Velocities in Ducts When the static suction has been fixed for a given hood, the air velocity in the duct may be determined from Equation 2. Air velocities for conveying a material should be moderate. Table 5 gives the velocities resistance is equivalent to a section of straight pipe approximately 10 diameters long, while with a throat diameter radius 1J4 times the dia meter, the resistance is about the same as that of seven diameters of straight pipe. . generally employed for conveying various substances. Equations 5a and 5b COLLECTORS may be used as tests to determine the conveying efficiency of a system8.* Velocities determined from these formulae should be increased by at least 25 per cent since they represent the minimum at which a stated size and density of material can be transported. The most common method of separating the dust and other materials from the air is to pass the mixture through a centrifugal or cyclone collector. In this type of collector the mixture of the air and material is introduced on a tangent, near the cylindrical top of the collector, and For vertical ducts: V = 13,300 - 'f-v 5+1 the whirling motion sets up a centrifugal action causing the compara (5a) 1 tively heavy materials suspended in the air to be thrown against the side For horizontal ducts: V = 6000 -- 5+1 of the separator, from which position they spiral down to the tail piece, (5b) while the air escapes through the stack at the center of the collector. where . The diameter of the cyclone should be at least 3J4 times the diameter V = air velocity in duct, feet per minute. 5 = specific gravity of particles. d = average diameter of largest particles conveyed, inches. Example 2. Granular materia], the largest size of which is approximately 0.37 in. in diameter, with a specific gravity of 1.40 is to be conveyed in a vertical pipe the velocity of the air in which is 4100 fpm; find whether the material can be transported at this velocity. of the fan discharge duct. When two or more separate ducts enter a cyclone, gates should be provided to prevent any back draft through a system which may not be operating. Cyclones working in conjunction with two or more fans should be designed to operate efficiently at twothirds capacity rating. The following formula is useful in computing the loss through a cyclone when the velocity of the air in the fan discharge duct is known: Substitute data in Equation 5a and multiply by 1.25: h =013(i)2 (6) V = 1.25 X 13,300 X ^1 X 0.37-67 where . Antilog (0.57 X log 0.37) -- 0.568; the required velocity is, therefore, 5500 fpm. Ac = the pressure drop through the cyclone, inches of water. V = the air velocity in the fan discharge duct, feet per minute. , . 8DallaValle, J. M.: Determining Minimum Air Velocities for Exhaust Systems. (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, September, 1932). . ' 380 ' If a cyclone is used to collect light dusts such as buffing wheel dusts, 381 American Society of Heating and Ventilating Engineers Guide, 1936 feathers and lint, the exhaust vent should be large enough to permit an air velocity of 200 to 500 fpm. This will, of course, require a cyclone of larger dimensions than given for the foregoing general case. When a high collection efficiency is desired, or the material is very fine, multicyclones may be used. These are merely small cyclones arranged in parallel which utilize the principle of high centrifugal velocity to attain separation. The capacities and characteristics of this type of separator should be obtained from the manufacturers. Cloth Filters Filters are used when the material collected by an exhaust system is valuable or cannot be separated efficiently from the air with an ordinaiy cyclone. They are also employed when it is desirable to recirculate the air drawn from a room by the exhaust system, which otherwise might entail considerable loss in heat. Bag filters which are properly housed may be operated under suction. Bag houses used in the manufacture of zinc oxide and other chemical products are operated on the positive side of the fan. .. Wool, cotton and asbestos cloths are commonly used as filtering mediums. When woolen cloths are employed, the filtering capacities vary from Y<i to 10 cfm per square foot of filtering surface, depending on the character of the material collected. The rates for cotton and asbestos cloths are lower. The type of filter cloth and the rates of filtration depend, of course, on the material to be collected and the fan capacity. The time increase of resistance varies with the amount of material per mitted to build up on the surface of the filter and can be determined only by experiment. The limits of the increase may be regulated by adjust ment of the shaking or cleaning mechanism. These limits may be regulated further according to the capacity of the fan and the effective performance of the hoods and the duct system. .. For additional information on Dust and Cinders, see Chapter 15, Air Pollution, p. 293. ' RESISTANCE OF SYSTEM * The maintained resistance of the exhaust system is composed of three, factors: (1) loss through the hoods, (2) collector drop, and (3)Jfriction drop in the pipes. . N. , The loss through the hoods is usually assumed to be equal to the suction maintained at the hoods. The collector drop in inches of water is given approximately by Equation 6, but where possible the resistance of the particular- collector to be used should be ascertained from the manu facturer. ' Friction drop in the pipes must be computed for each section, where there is a change in area or in velocity. Find the velocities 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. 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; . 382 21Chapter --Industrial Exhaust Systems 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 limits9. Top 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." Commonly accepted values of threshold limits for the usual gases and vapors are given in Table 7. SELECTION OF FANS AND MOTORS Manufacturers generally provide special fans for the collection of various industrial wastes. These are available for the collection of coal dust, wood shavings, wool, cotton and many other substances. For Table 7. Threshold Limits of Common Vapors and Gases* Substance Spec. Goat, op Gab ob Vapos (Atb 1) Chlorine............... Carbon tetrachloride......... '2:486 5.5 1.2678 2.2638 0.9671 1.190 2.73 1.1 5.3 Inflammable Limits (%) Physiological Action Maximum Allowable Concentration (ppm) non-irtflamm, do do . do " 12.5-74 4.3-46 1.4-7.0 7.5-26.5 non-inflamm. ` irritant ' do . .do . do asphyxiant do anesthetic . do . do 0.35 0.80 10.0 10.0 100.0 85-130 100.0 - 100.0 100.0 aTaken from The Prevention of Occupational Diseases, by R. R. Sayers and J. M. DallaValle {Me chanical Engineering, Vol; 57, No. 4, April, 1035). particular features concerning special fans, consult the Catalog Data, Section of The Guide and manufacturers' data. When substances having an abrasive character are conveyed, the fan blades and housing should be protected from wear.. This may. be accomplished.by placing a collector on the negative side of the fan or by lining the housing and blades with rubber. If no future expansion of an exhaust system is contemplated, the fan motor should be chosen to provide the calculated air volume. Should, however, the exhaust system be required to handle more air in the . future, the motor should be adequate for the maximum load anticipated. Further information regarding the choice of fans and motors is given in" Chapters 17 aind 42. PROTECTION AGAINST CORROSION The removal of gases and fumes in many chemical plants requires that metals used in the construction of the exhaust system be resistant to r Criteria for Industrial Exhaust Systems, by J. J. Bloomfield (A.S.H.V.E. Transactions, Vol. 40, 1934). 383 American Society of Heating and Ventilating Engineers Guide, 1936 Table 8. Materials to be Used for the Protection of Exhaust Systems Against Corrosion Ttfb or Fmo Coitotbd Protective Material to bb Used Chlorine Hydrogen sulphide...;_____ Ammonia______ ________ ____ Nitrous gases.._____________ Rubber lining or chrome-nickel alloys Aluminum coated iron, aluminum, high chrome-nickel alloys Iron or steel High chrome-nickel alloys . Rubber lining, chrome-nickel alloys Nickel-chrome alloys "Condensed from data given by Chilton and Huey (Industrial and Engineering Chemistry, Vol. 24,1933). chemical corrosion. A list of the materials which may be used to resist the action of certain fumes is given in Table, 8. 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 and fumes as chlorine and hydrochloric acid. PROBLEMS IN PRACTICE 1 What determines the efficiency of an exhaust system? It is dependent upon its effectiveness in reducing the concentration of dust, fumes, vapors and gases below the safe or threshold limit. 2 Are state regulatory requirements as to suction applicable to all sorts of dust collecting installations? As a rule the regulations refer only to grinding wheel and buffing wheel systems. 3 What is the most common method of reducing total air volumes handled in cases employing large hoods over apparatus covering a large area? The use of the petticoats on large hoods which permits a comparatively high air velocity at the rim of the hood and controllably small velocities in the center. ' 4 What other types of collectors are available for use in the place of cyclones and filters when chemical'and physical conditions obviate the possibility of the use of them? . <- '" Devices such as scrubbers and contactors, using water or other contacting liquids, and electrical precipitators. . . 5 What is the most frequent error made in dust collector system design? The omission of some means of putting into the workroom air. having the proper charac- . teristics to replace'that which has been exhausted. . . ." 6 Are there available means for testing the performance of dust collecting systems when they are.required to meet high industrial hygienic standards? Yes. Such means are set up by the United States Public Health Service and by the Standard Code for Testing and Rating (Vir Cleaning Devices Used in General Venti lation Work. (Chapter 44).. - ^. . . :7 7 Why. is it not permissible to connect up emery wheels and buffing wheels to the same exhaust system? ;, Chapter 21--Industrial Exhaust Systems Emery wheels and buffing wheels should be handled-by separate systems because of the fire hazard, as it is possible for sparks from the emery wheels to ignite the lint and dust from the buffing wheels when both are carried through the same system. g Give an important characteristic of centrifugal type dust collectors which should be given consideration when applying this type of collector to instal lations requiring high separating efficiencies. The separating action of a cyclone or centrifugal type collector depends largely on centrifugal force. Reducing the radius of air flow increases the centrifugal force for a given velocity of flow. Accordingly, the smaller size units usually give higher separating factors, and better results can sometimes be obtained by using a number of small col lectors instead of one large unit. . 9 Mention some general suggestions relating to the design of efficient in dustrial exhaust systems. " a. Endeavor to obtain a maximum degree of effectiveness with a minimum volume of air, by the use of well designed hoods closing in the sources of fumes or material to be removed so located as to take advantage of the natural direction taken by the fumes or materials when leaving their source. b. Give particular care to the velocity of flow. The duct velocities for material con veying systems must be high enough to properly carry the material, but they should not be higher than necessary because excessive velocities increase the pressure requirements and result in a waste of power. ' c. Select the type of fan best suited to the job. For installations where stringy material is handled do not use a fan wheel which has a shroud. d. When handling the refuse from various machines, study the grouping and operating cycles of the machines. Connecting a large number of machines into one system is frequently very uneconomical. . Avoid unnecessary distances and bends in laying out the piping system. 10 The static pressure measured at the throat of a buffing wheel hood is 2 in. and the velocity head measured with a Pitot tube is 1.6 in. Calculate the restriction coefficient f. From Equation 2, V = 4005 / y/ fit- From the theory of air flow, V = 4005 y/ hv. Hence, y/H7 = / y/ Ator 11 A tank, 4 ft by 8 ft, contains a fluid which gives off injurious vapors. A large hood is located 30 in. above the top of the tank and extends slightly over its edges. Assuming that a velocity of 60 fpm is required to adequately control the vapors near the edges of the tank, calculate the air flow required. Using Equation 4, P=2X4 + 2X8 = 24ft;/?=30 inches = 2.5 ft; V = 60 fpm. Hence, Q = 1.4 X 24 X 2.5 X 60 = 5040 cfm. 12 Silica dust with a specific gravity of 2.65 is being conveyed in a duct system. The velocity measured in a vertical portion of the system is found to be 2700 fpm. What is the maximum diameter particle transported at this velocity? O AR Using Equation 5a, 2700 13,300 X X _ 0.00 from which d = (0.281 *75 = 0.11 in. 385 1 and 1936 .ofAmerican Society Heating Ventilating Engineers Guide, 13 What important factors must be considered in the determination of resistance for an exhaust system? The maintained resistance of an exhaust system is composed of three factors, namely, (1) loss through the hoods, (2) friction drop through the pipe system, and (3) collector drop. .. 14 What special materials may be used to resist chemical corrosion in a system exhausting gases and fumes? Various protective materials are available for exhaust systems depending largely upon the type of fumes conveyed.. Nickel-chrome alloys, aluminum coated metals and rubber linings are extensively used. Also protective rubberized paints are available which may be applied for conveying chlorine and hydrochloric acid fumes. 1 a ? ' ' Chapter 22 FAN SYSTEMS OF HEATING Types of Systems, Blow-Through, Draw-Through, Heating Units, Design9 Temperatures, Weight of Air to be Circulated, Tempera ture Loss in Ducts, Heat Supplied, Heating Units and Washerf Grate Area, Boiler Selection, Weight of Condensate, Static Pres sure, Fans and Control AFAN system of heating depends upon fans and blowers to distribute air through ducts from one centrally located plant. This chapter considers heating arid humidifying systems of this type whereas similar systems arranged for cooling and dehumidifying are discussed in Chapter 9. A special type of central fan system, the mechanical warm air or fan furnace system, which is especially adapted to residences, churches, halls, and other small buildings, is covered in Chapter 23. TYPES OF SYSTEMS In the indirect type of central fan heating and air conditioning systems, steam is usually the medium by which heat is transferred from the boiler, or other source of heat, to the heating units. If the system is intended solely for heating, the air is passed over one or more stacks or batteries of heating units and then conveyed to the spaces for which it is intended . through a system of ducts. In some cases, a predetermined amount of. outside air is introduced for ventilating purposes, whereas in others the moisture content is controlled by passing the air through a washer or humidifier. If the apparatus is designed to control simultaneously the temperature, humidity, air motion, and distribution, it is known as an air conditioning system. In the split system, the heating is accomplished by means of radiators or convectors, and the ventilating or air conditioning by means of the central fan apparatus. In the combined system, the entire operation of heating, ventilating, and air conditioning is handled by the central fan system. A common arrangement of the central fan system of heating is illus trated by Fig. 1 and consists of a fan, a heating unit (heater) enclosed by a shget metal casing connected with the suction side of the fan, a sheet metal casing connected to the heating unit casing run to the outside of the building and provided with an adjustable opening inside the building for recirculation of the air when desired, and a duct system attached to the fan outlet to convey and distribute the air to various parts of the building to be warmed by the apparatus. The fan is ordinarily motor-driven; there are, however, many cases when a direct-connected steam engine may be used to advantage. In this event the exhaust from the engine can be con- 386 387 of andAmerican Society Heating Ventilating Engineers Guide, 1936 nected to one or more sections of the heater, depending upon the con densation rate of the engine. The recirculation duct connected with the opening in the suction duct should be extended to a point as near the floor as possible. . When ventilation is not a requirement or is considered relatively unim portant, as in shop and factory heating, and the number of persons vitiat ing the air is small compared with the cubical contents of the building, or the process does not generate obnoxious gas or vapors, the air may be recirculated, sufficient outside air for ventilation being supplied by infiltra- Fig. 1. Arrangement of a Central Fan Heating System (Draw-Through) Canvas Connection ' Heater Fig. 2. Arrangement for Heating Unit (Blow-Through) tion. The amount of heat to be supplied the heating unit in this case is the same as would be required for a direct radiation installation. ; , When ventilation is a requirement to be met, an arrangement similar to that shown by Fig. 1 may be employed. Since the amount of air necessary for heating is generally in excess of the amount required for ventilation, considerable fuel economy may be effected by recirculating a portion of the air. In this case only sufficient outside air is drawn into the system to meet the ventilation requirement and the remainder of the air, required for heating, is. recirculated. This may be readily effected by an arrange ment of ducts and dampers on the suction side of the fan as previously mentioned. If the outside air introduced is to be washed or conditioned the washer or humidifier and tempering coil may be added between the inlet for the recirculated air and the fresh air intake. _' 388 Chapter 22--Fan Systems of Heating Blow-Through, Draw-Through When the heating unit is located on the suction side of the fan, the system is known as draw-through. (See Fig. 1.) When the heating unit is located in the discharge from the fan, the system is known sis blow- through. (See Fig. 2.) The draw-through combination is used for factory and toilet room installations because a more compact arrangement of the apparatus usually is possible. In addition, air leakage will be inward. The blow-through combination is used principally in schools and public buildings, and for all booster coil arrangements where different tempera tures and independent temperature regulation are required for different heated spaces. In public building installations, the fan frequently blows the heated air into a plenum chamber from which the air ducts radiate to the various rooms of the building; this arrangement is sometimes called ' the plenum system. . HEATING UNITS The heating units for central fan systems using steam as the heating medium may be classified as (1) tempering coils, (2) preheater coils, (3) reheater coils, (4) booster coils, and (5) water heaters, either open or closed. Tempering coils are used with ventilating and air conditioning systems for raising the. temperature of the outside cold air to above freez ing, or 32 F. They are not required for heating systems where all of the air is recirculated, since the temperature of the recirculated air will be above freezing. Preheater coils are used with air conditioning systems to raise the temperature of the air from that leaving the tempering coils to such a temperature that in passing through the water sprays of the washer (without water heater) the air will become partially saturated (adiabatically) having a moisture content corresponding to the required dew point temperature. Preheater coils therefore supply heat as necessary to control the dew-point temperature. The reheater coils are used to raise the temperature of the air leaving the tempering coils (in the case of a heating or ventilating system) or the air leaving the washer (in the case of an air conditioning system) to that necessary to maintain the desired tempera ture in the'rooms or spaces to be heated or conditioned, except where booster coils are used, in which case the reheater coils raise the air tem perature to approximately room temperature, or slightly higher. Booster coils are installed in the duct branches to control the temperature of the air entering the rooms or spaces for which it is intended. Water heaters are used on an air conditioning system to control the dew-point temperature. They are used mainly for industrial work, seldom for comfort conditioning. They are not used where preheater coils are employed. The open type supplies steam directly to the spray water, while the closed type utilizes a heat interchanger by which the steam imparts its heat to the spray water. Where water heaters are required for comfort conditioning, the closed type is used. # The heating units for central fan systems in use at the present time con sist either of pipe coils, finned tubes of steel, copper, brass or other metal, cast-iron sections with extended surfaces, or the cellular type. Steam is passed through these heating units and the air to be heated is passed over their exterior surfaces. - :. 389 American Society of Heating and Ventilating Engineers Guide, 1936 In selecting a heating unit for any particular service; the choice should be based on the desired requirements as follows: 1. Final temperature desired. 2. Loss in pressure (or friction) of air passing over the heating unit. 3. Air velocity over the heating unit. 4. Free area or face area of heating unit. 5. Ratio of heating surface to net free (or face) area. ' 6. Air volume required. 7. Number of rows of pipes, tubes, or sections. 8. Amount of heating surface. ' . 9. Steam pressure drop through the heating unit. 10. Weight of heating unit. .' . . Final Temperature Desired. The choice of a heating unit is largely influenced by the final temperature desired, when the entering air tem perature and steam pressure available at the heating unit are specified. These data are obtainable from manufacturers' catalogs. Loss in. Air Pressure (or Friction). The allowable friction through the heating unit is one of the first factors to be determined in the selection of the apparatus. The velocities of air through various types of heating units will not necessarily be the same, but for any particular job the velocity through the heating unit should be a secondary consideration and the allowable friction or air pressure loss should be fixed approximately before proceeding with the selection of the heating unit. The loss in air pressure (or friction) through the heating unit should not exceed a pre determined maximum allowable amount for economical operation and for moderate size and first cost of installation. In public building work, the maximum allowable friction through both tempering coil and reheater coils should never exceed 5^ in. of water and it is advisable that the friction be kept considerably lower than this figure if possible. A tempering coil friction ranging from 0.10 to 0.20 in. of water is considered satisfactory. The air pressure loss for reheaters ordinarily ranges from 0.20 to 0.40 in. of water. In factory work, the maximum friction through the heater should never exceed 0.8 in. or 1 in. of water and it is advisable to figure the heaters at lower frictions if possible. Velocity through Heating Unit. This velocity has generally been, given in manufacturers' tables as being measured at 70 F and in most cases refers to the velocity through the net free area of the heating unit, or through the net space between the pipes, tubes or sections. Although most manufacturers give suitable velocities measured at 70 F, certain manufacturers show velocities measured at 65 F and others indicate velocities measured at the average air temperature through the heating unit. Many new heating units, however, specify net face areas with cor responding velocities instead of velocities through net free areas. , In either case, manufacturers publish the corresponding friction or air-"' pressure loss in tables. The velocity through the net free area of the heating unit averages about 1000 fpm and that through the net face area about 500 fpm. The volume of air to be heated in any particular case is determined after consideration of the ventilation requirements, heat losses, and quantity of air required for proper circulation, as explained in Chapters 3 and 7. 390 Chapter 22--Fan Systems of Heating The number of rows of pipes, tubes, or sections or the amount of heating surface to be used may be selected from manufacturers' catalogs after the quantity of air handled and the heat load are known. Savings in oper ating expense or cost of installation should result from a proper selection of heater and by-pass areas. For example, instead of having the entire air quantity go through a one-row heating unit, it may be advantageous to use a two-row heating unit and a properly sized by-pass. Thus, when no heating is being dpne, a suitable by-pass damper may be opened to place a lighter load on the fan. The steam pressure drop through the heating unit is also tabulated in manufacturers' data tables. The sizing of steam supply and return piping, allowing for drops through heating units, is explained in Chapter 32. Weight of Heating Unit. In the design of a heating system, the weight limitations of heating units are determined by the location of the units. Obviously, if there is no loading limitation imposed, any type of heating unit may be selected. On the other hand if the heating unit is to be hung from the ceiling, it may be desirable to use the lightest unit which will accomplish the work required. DESIGNING THE SYSTEM The general procedure for the design of central fan systems is as follows: . 1. Calculate the heat loss for each room or space to be heated. 2. Determine volume of outside air to be introduced. 3. Assume or calculate temperature of air leaving registers or supply outlets. 4. Calculate weight of air to be circulated. 5. Estimate temperature loss in duct system. 6. Calculate heat to be supplied the heating units and washer. 7. Select heating units and washer from manufacturers' data and performance curves. 8- Calculate total heat to be supplied. . 9. Calculate grate area and select boiler. 10. Design duct system. 11. Calculate total static pressure of system. 12. Select fan, motor, and drive. The heat losses (H) should be calculated in accordance with the pro-, cedure outlined in Chapter 7. If a positive pressure is maintained by the central fan system in the room or space to be ventilated or conditioned, there will ordinarily be very little infiltration of cold outside air through the cracks and crevices of the space. Consequently, the volume of air introduced into the space at the assumed or calculated outlet temperature need only be sufficient to provide for the transmission losses, plus about one-third of the infiltration losses. The exfiltration of heated or con ditioned air through the cracks and crevices of the space should be pro vided for by malang the usual allowance for the infiltration losses in arriving at the total heat loss of the space. The air required to make up for this exfiltration of heated or conditioned air will be brought in at the outside air intake and may be included as a part of the-outside air neces- 391 of andAmerican Society Heating Ventilating Engineers Guide, 1936 sary for the ventilating requirements. The heat required to raise this air to the conditions maintained in the room must be provided by the tem pering coils, preheater coils, and reheater coils. If a positive pressure is not maintained in the room or space to be conditioned, the normal in filtration of outside cold air will take place in this room, and the outlet temperature, together with the required air volume at this temperature, must be sufficient to provide for both infiltration and transmission losses. Volume of Outside Air The volume of outside air required for ventilation or air conditioning purposes may be determined from data in Chapter 3. In no case shall less than 10 cfm per person be introduced. The heat required to warm the outside air introduced for ventilation purposes (H0) may be determined by means of the following formula: where H0 = 0.24 (/ - <,) M0 . (1) 0.24 specific heat of air at constant pressure. t = room temperature, degrees Fahrenheit. . ; to = outside temperature, degrees Fahrenheit. M0 = weight of outside air to be introduced per hour, in pounds = 60 d0Q0. Qo = volume of outside air to be introduced, cubic feet per minute. do = density of air at to, pounds per cubic foot. . . . . Example 1. A building in which the temperature to be maintained at 70 F requires 10,000 cfm. If the outside temperature is 20 F, how much heat will be required to warm the air introduced for ventilation purposes to the room temperature? ' Solution. 10,000 X 60 = 600,000 cfh; do = 0.08276 (Table 1, Chapter 1) ; M0 = 0.08276 X 600,000 = 49,656 lb; t = 70 F; lo = 20F;7fo = 0.24 X (70 - 20) X 49,656 = 595,872 Btu per hour. Temperature of Air Leaving Registers If the system is to function only as a heating system, that is, entirely as a recirculating one, the temperature of the air leaving the register outlets must be assumed. For public buildings, these temperatures may range from 100 to 120 F, whereas for factories and industrial buildings the out let or register temperature may be as high as 140 F. In no case should the outlet temperature exceed these values. . " For ventilating or conditioning systems, the temperature of. the air leaving the supply outlets may be estimated by means of the following formula: . H . ty = GO d Q X 0.24 + 1 . (2) where ., ty -- outlet temperature, degrees Fahrenheit. , II = heat loss of room or space to conditioned, Btu per hour. '. .r i Q = total volume of air to be introduced at the temperature t, cubic feet per minute. d -- density Of air, pounds per cubic foot. '. If the outlet temperature (%) as determined from Equation 2 exceeds 120 F for public buildings, or 140 F for factories or industrial buildings, 392 Chapter 22--Fan Systems of Heating these respective outlet temperatures should be used as factors in the following equation5 to determine' the volume of air to5 be introduced into the room or space: . -. ' Q = 60 d X 0.24 (ty - t) (3) Example 2. The heat loss of a certain auditorium to be conditioned is 100,000 Btu per hour. The ventilating requirements are 1,500 cfm and the room temperature 70 F. Determine the outlet temperature. ' Solution. Substituting in Formula 2, loo,non ty + 70 = 131.7 F 60 X 0.07495 X 1500 X 0.24 Inasmuch as this temperature is excessive, it will be necessary to assume an outlet temperature, which will be taken as. 120 F, and to calculate the amount of air to be introduced into the room at this temperature to provide for the heat loss. Substituting in Equation 3, 100,000 16cr r Q - 60 X 0.07495 X 0.24(120 - 70) = 1850 cfm (at temPerature . Weight of Air to be Circulated The total weight of air (M) to be introduced into the room or space to be heated or conditioned is given by the following formulae: , M H 0:24(ty~t) = 60 dQ W where M,= Mo + Mr Mo -- 60 doQo (5) ' (6) d = density of air at temperature f, pounds per cubic foot. do = density of air at temperature to, pounds per cubic foot. . Qo = volume of outside air at temperature to, cubic feet per minute. Mo = weight of outside air, pounds per hour. Mr = weight of recirculated air, pounds per hour. . , .. Example 8. Using the data of Example 2 and an outside temperature of 20 F, what will be the values of M, Ma and MT? -' ' ' Solution, d 0.07495; do = 0.08276; Q = 1850; Qo = 1500; H = 100,000. ' M= -100,000 0.24 X (120 - 70) 8,333 lb Mo = 0.08276-X 60 X 1500 = 7,448 lb Mr = M - Mo = 8,333 - 7,448 = 885 lb . Temperature Loss in Ducts . .. The allowances (4) to be made for temperature drop through the duct system are as follows: ' 1. When the duct system is located in the enclosure to which the air is being delivered, as in a factory, it may be assumed that there is no loss between the reheater coil and the point or points of discharge into the enclosure. , 393 of andAmerican Society Heating Ventilating Engineers Guide, 1936 2. For ducts run underground an allowance shall be made based on the estimated heat loss of the duct, assuming the average temperature of the ground to be 55 F. 3: For galvanized ducts with the usual ranges of air temperature and velocity, the coefficient of heat transmission may be taken as 1.7 Btu per hour per degree difference between the mean temperature of the air in the duct and that surrounding the duct. The heat loss may then be expressed by H = 1.7 x DL ( (7) and also by H = 0.24 M (ft -- ty) = 60 D'Vd X 0.24 (ft - ty) (8) Equating (7) and (8) 1.7 x DL ( ^ ) - ft, = 3.6 x D*Vd (ft - ty) ft + ty - 2ft, = 4.235 D Vd ti -- ty' L (9) where H = heat loss from the duct, Btu per hour. D = diameter of duct, feet. ' L = length of duct, feet.' ft = temperature of air entering the duct. . ty = temperature of air leaving he duct. to = temperature of air surrounding the duct. . M = weight of air passing a given cross section of the duct per hour. V -- velocity of aiir in the duct, feet per minute, at specified temperature. d = density of the air at the specified temperature at which V is measured. . ' Usually all the values in Formula 9 may be approximated except ft, the initial or entering temperature, which can be readily found where the others are known or assumed. Example 4- Determine the temperature drop in a galvanized duct 20 in. diameter and 60 ft long carryingair at a velocity of 1200 fpm measured at 70 F, to be delivered at. a temperature of 140 F when the air surrounding the duct is at a temperature of 50 F. Solution. Substituting in Formula 9, ' ft + 140 - (2 X 50) ft - 140 4.235 X 1.666 X 1200 X 0.07495 60 ft = 158.7 F\ . . temperature drop = 158.7 -- 140 = 18.7 F Example 6. An uninsulated 12 in. diameter galvanized duct extends 50 ft through an unconditioned room to supply 80 F cool air to an adjacent space. If the average tem perature of the air surrounding the duct in the unconditioned room is 100 F and the velocity of the air through the duct is 1000 fpm, measured at 70 F, determine the tem perature gain which must be allowed in passing the air through the unconditioned room. Solution. Substituting in Formula 9, ' ft + 80 - (2 X 100) ft - 80 4.235 X 1.0 X 1000 X 0.07495 . 50 . ' : ft - 120 = 6.34 (ft - 80) -5.34 ft = 120 - 507 . 394 Chapter 22--Fan Systems of Heating ft = 72.3 F temperature gain = 80 -- 72.3 = 7.7 F Therefore, air having a temperature of 72.3 F must be introduced at the end of the 50 ft duct in order to supply 80 F air to the conditioned space. Heat Supplied Heating Units and Washer The following cases may arise in practice: A. The heating of the building is done entirely by means of a central fan system, all of the air being drawn from the outside. B. Similar to A, except that all of the air is recirculated. . C. A portion of the air is recirculated, and the remainder is drawn in from the outside. D. Air at the same temperature is to be delivered to all the rooms. A constant relative humidity is maintained in the building and all of the air circulated is drawn from outside the building. (Not applicable to the heating of various rooms where individual control of each room is desired.) E. Outside air, return air, and by-pass air are used with the reheater located in by pass air chamber. F. Arrangement of apparatus where individual control of-the temperature for each room is required in conjunction with air washer equipment to maintain a constant relative humidity in the rooms. The air washer is provided with a water heater for the spray water, capable of fully saturating the air. A section of preheater may be used for this purpose in place of the water heater. With this arrangement and with a uniform temperature of air entering the rooms, it is impossible to maintain the same room tem perature throughout the building because the weight of air to be delivered to each room is determined and fixed by the ventilating requirements. In analyzing these cases, the following symbols will be used: H = heat loss of the room or building, Btu per hour. Hi = heat to be supplied to the reheater coil, Btu per hour. H, = heat supplied tempering coil, or tempering coil and preheater, Btu per hour. H, = heat supplied air washer by water heater, Btu per hour. Ht = heat to be supplied booster coil, Btu per hour. M = weight of air to be introduced into the room or building, pounds per hour. Mr = weight of recirculated air, pounds per hour.. . Mb = weight of air by-passing washer, pounds per hour. . M0 = weight of air drawn in from outside, pounds per hour, ft) -- mean temperature of outside air, degrees Fahrenheit. t = mean air temperature to be maintained in the room or building; degrees Fahrenheit. 's~ ti = mean temperature of the air entering the reheater coil. h`= v mean ..O' temperature of the air leaving the reheater coil, h. = temperature loss in the duct system, <y = temperature of the air leaving the duct outlets. h. = average temperature of air entering tempering coil. .. -- temperature of air entering washer: 0.24 = specific heat of air at constant pressure. 395 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Chapter 22--Fan Systems of Heating . Fig. 3. Heating Unit and Fan Arranged for Outside Air Circulation (Case A) ' Case A, (Fig. 3) All of the air circulated to be drawn from outside the building, in which case h = to. : .. . .. II, ~ 0.24 (/, - t0) Ma. . . ., (10) Hi = 0.24 (t, - k) M0 (11) Example 6. Theheat loss H for a .certain factory , building is 70Q.000 Btu per hour. .The mean inside temperature f to be maintained is 65 F. The assumed outside air. tem perature to is 0 F;.-<* = 0, - ly' = t, and is assumed to be 140 K. The temperature living the tempering coil is assumed to be 35 F. Required, Hi and Hj. From Equation 4, M = "700,000 0,24 (140 - 65) = 38,889 lb. per hour. Ht = 0.24 X (35 - 0) X 38,889 = 326,667 Btu per hour. Hi = 0.24 X (140 - 35) X 38,889 = 980,003 Btu per hour. H, + Hi = 326,667 + 980,003 = 1,306,670 Btu per hour. Air Returned from .Heated Space. --]L^Automatic Valve . Air Leaving Fan at ty . -^Pulley . ELEVATION Fig. 4:f . Arrangement for Recirculation (Case B) . ; Case (Fig.' 4) All of the air is to bejrecirculated, in which case h = /. . MT = 38,8891b . '' Mi = 0.24 (tt - h) Mt. . Hi = 0.24 (140 - 65) X 38,889 = 700,000 Btu. per hour. . . This example illustrates the. saving in fuel consumption by th$ recir culation of the air. The heat to be supplied the apparatus is the same as that required for a direct system of heating and is equal to the heat loss of the building {Hy = IT), in the example 700,000 Btu per hour 'as compared with 1,306,670 for Case A. ;. .. . 396 a f i * \ Fig. 5. Combination of Recirculated Air and Outside Air (CaseC) Qase C. (Fig. 5) A portion of the air circulated is recirculated air and the remainder, as may be required for ventilating purposes, is drawn in from the outside. According to Equations 4 and 5, . M = Mo + Mr H 0.24 (ty - t) The temperature of the resulting mixture of outside and recirculated air entering the tempering coil is: Ps = Mato + Mrt M (12) Example 7. Assuming that a positive supply of outside air (do = 0.0864) is required for ventilation at the rate of 90,000 cu ft per hour in the preceding example, then Ma = 0.0864 X 90,000 = 7776 lb per hour are required, measured at 65 F. Mr = M - Mo = 38,889 - 7776 = 31,113 lb b'j- ; ' h _f7776 X 0 d- 31,113 ----------- 38,889 X 65 = 52 F Hi = 38,889 X 0.24 (140 - 52) = 821,336 Btu. This amount of work may be accomplished with one or more banks of heating units, that is, either a single reheater or a tempering coil and reheater. The three preceding cases refer to installations in which conditioning the air to maintain certain relative humidity requirements does not enter into the problem, as for example, certain types of industrial installations. In practically all modern public buildings, theaters, schools, and in many industrial installations, the ventilating requirements include the provision for washing and humidifying the air delivered to the various rooms of the structure. '. In the following cases it is assumed that in addition to maintaining a mean, room temperature t, the heating and ventilating; apparatus is required to maintain a constant relative humidity in the rooms. . 397 of and 1936American Society Heating Ventilating Engineers Guide, Chapter 22--Fan Systems of Heating the water sprays will become partially saturated (adiabatically) having a moisture con tent per pound of air equal to saturated air at 41 F. If the incoming air is warmed to = 88 F (requiring a two-section-depth heating unit) it will be cooled in the washer to 64 F, with a temperature drop of 88 -- 64 = 24 deg. If the humidifying efficiency of the washer were 100 per cent, the air would become adiabatically saturated at 52 F after a temperature drop of 88 -- 52 = 36 F. The efficiency of the washer is, however, only 67 per cent, so that the actual temperature drop will be 0.67 X 36 deg or 24 deg, as used. . The heat to be supplied the reheater is in this case Hi -- 0.24 (h -- 64) M Btu per hour, and the heat to be.supplied to the tempering coil and preheater is Hi => 0.24 (88 -- to) M. The total heat required by the apparatus is H, + Hi, no heat being supplied to the washer. Fig. 6.' Outside Air Circulated; Constant Relative Humidity in Room (Case D) Case D. (Fig. 6) The maximum relative humidity that may be maintained within the building without the precipitation of moisture on single glazed sash when the outside temperature is 30 F is approximately 35 per cent. If the inside temperature t is 70 F, 35 per cent relative humidity corresponds to a dew-point temperature of 41 F. (See psychrometric chart.) The installation shown in Fig. 6 contemplates the use of a tempering coil, an air washer provided with a water heater, and a reheater. The tempering coil, one section in depth, warms the incoming air to approximately 35 F to prevent freezing any of the spray water. The air passing through the'spray chamber is saturated and leaves at a tempera ture of /i = 41 F. .The heat to be supplied the reheater is: 'r H\ - 0.24 (<j -- 41)M Btu per hour. The heat to be supplied the tempering coil is: . H> = 0.24 (35 -- to) M Btu per hour. The amount of heat, per pound of air circulated, to be.supplied'the humidifying washer or humidifier is the difference between the heat content of the assumed dry air entering the washer at a temperature of /w = 35 F and that of the leaving saturated air at <i = 41 F .(Table 5, Chapter 1), or: o. 'I'-.- . 15.657 -- 8.397 = 7.28 Btu perpoiind of dry air. The amount of heat required for the washer is: Ht.= 7.26 M Btu per hour. 1 The total amount of heat required by the apparatus is,' therefore: Hi + Hi + Hi Btu per hour. , If a washer having a humidifying efficiency of 67 per cent without water heater is em ployed it will be necessary to heat the outside air drawn into the apparatus by'm'eans of the tempering and preheater coils to such a temperature that the air in passing through 398 Fig. 7. Outside Air Circulated; Constant Temperature and Relative Humidity Maintained in Each Room (Case E) Case E. (Fig. 7) The temperature ty will ordinarily be different for each room. With H and M fixed, 0.24 (ly -- t)M = H, or . h = 0.24 M + ` . In order to provide the proper temperature for each room, a booster coil is generally installed in each supply duct near the outlet to control the out let temperature ty. The amount of steam supplied to these booster units is usually controlled automatically by individual thermostats. The heat required by the booster coils depends on the temperature range through which the air is heated and the quantity of air, Or H, = 0.24 (ty -h- QM (13) Heat to be Supplied . The amount of heat to be supplied (H') is equal to the sum of the heat requirements of the various heating units and the water heater of the washer, if any, plus the allowance for piping tax. (See preceding Cases A to E.) 399 i- of andAmerican Society Heating Ventilating Engineers Guide, 1936 Grate Area, Boiler SelectionThe required grate area may be determined by the following formula: where H G FXE X C (14) G = required grate area, square feet. F -- calorific value of fuel, Btu per pound. . C = combustion rate, pounds per square foot of grate per hour. E -- boiler and grate efficiency, per cent. . Example 8. Using the data in Example 5, and assuming coal having a calorific value of 12,000 Btu per pound, a combustion rate of 7 lb per square foot, and a performance efficiency of 0.60, and neglecting the piping tax, ,,_ 1,306,670 _ ,,,, G 12,000 X 0.60 X 7 6scl 4 Weight of Condensate The normal weight of condensate to be handled from central fan sys tems may be estimated by means of the following formula: where w _ 60 dQ X 0.24 X Af Afg (15) W = weight of condensate, pounds per hour. Q = total volume of air, cubic feet per minute. At = temperature rise of air, degrees Fahrenheit. Afg = latent heat of steam in the system, Btu per pound. Ducts and Outlets, Air Filters, Air Washers The design of the duct system should be based on data contained in Chapter 20. Air washers and humidifiers are described in Chapter, 11. For information on air filters, see Chapter 16. t Static Pressure . The total static pressure against which the system must operate may be found by summing up the static losses through the complete system from the outside air intake to the discharge outlets or nozzles. _ This means that the loss due to friction must Be determined for each piece of apparatus involved. Most of these values may be. obtained from manu facturers' data tables.- For a simple system, the following static pressure drops may be assumed: ... . 1. Outside.air inlet, comprised of screen, louver and short-duct, may have a loss of 0.2 in. of water. . s' 2. A typical oil filter at rated capacity and velocity has a drop of 0.25 in. of water. 3. The loss of one row of a standard make tempering stack equals 0.09 in. water. 4. The loss of one row of a standard make preheater equals 0.10 in. water. , 5. A standard humidifier at rated velocity may have a loss of aboht 0.35 in. water. 6. The loss through one row of a standard make reheater equals 0.12 in. water. . 7. A fair assumption 'for. duqt losses on a simple system is 0.25 in. water. . . 8. The static pressure for a nozzle type outlet may be taken as 0.1 in. water. . ^ 400 Chapter 22---Fan Systems of Heating The sum of these values equals 0.2 + 0.25 + 0.09 + 0.10 + 0.35 + 0.12 + 0.25 + 0.1 = 1.46 in. which is the static pressure against which the system must operate. . Fans and Control The selection of fans may be based on data contained in Chapter 17 and for motors in Chapter 42. Because centrifugal fans reach their maximum efficiency when working against the resistance offered by the average central fan heating system, they are well adapted to such system^ and are generally used. Information on temperature control for central fan systems is given in Chapter 14. PROBLEMS IN PRACTICE 1 Consider a blast heating system handling 10,000 cfm: The resistance to air flow offered by one coil arrangement is 0.9 in. of water and by another coil arrangement is 0.2 in. of water. The fan operates 4000 hours per year and the combined efficiency of motor and fan is 60 per cent. Determine the annual energy saving if the second coil.is used. . ' Difference in system resistance = 0.9 -- 0.2 = 0.7 in. of water. D , -. . ,, 10,000 X 0.7 , Q, , Reduction in power input = 5350 x 0 60 = 1"3 "P Annual energy saving = 1.83 X 0.764 X 4000 = 5480 kwhr. 2 0 What saving results from recirculating some of the room air and reducing the amount of outside air? Because outside air must be heated to room temperature, reducing the amount of outside air produces a proportionate saving in heat or fuel. 3 What items make up the total heating load in a central fan heating system? 1. The net heat loss from the conditioned space. . 2. The heat required for evaporation of water for humidification. 3. The heat required to raise the temperature of outside air to room temperature, 4. Heat losses from pipes and ducts. 4 Why is it necessary to determine the total static pressure of a central fan heating system? To select a fan of maximum efficiency and to determine the power required to operate the fan. ' : 5 A group of three drafting rooms, having a total volume of 27,000 eu ft, a transmission loss of 110,100 Btu per hour, and an infiltration loss of 34,200 Btu per hour_on the basis of 0 F outdoors and 70 F room temperature, is to be heated by a recirculating hot blast heating system with air entering the rooms at 116 F. How many cubic feet per minute, measured at 70 F, will be required? Substitute in Equation 3. H = 110,100 + 34,200 = 144,300. Btu.per hour; = 116 F; t - 70 F, Q = 6Q x 0 074g5 x 0 24 (116 - 70).= 2900 cfm' . 6 In the preceding question, if the hot air loses 4 F between heater and rooms, how many pounds of steam per hour at 1-lb gage will the heating sections condense? . 401 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Substitute in Equation 15. Q = 2900 cfm, from solution of Question 5; At = 116 + 4 -- 70 = 50 F; hfg = 968 Btu, from steam table in Chapter 1. 60 dQ X 0.24 X At = 60 X 0.07495 X 2900 X 0.24 X 50 W= h[s 968 161.8 lb per hour. 7 The same rooms are converted to chemical laboratories, requiring the intro . duction of-12 changes of outside air, measured at 70 F, per horn: to permit the exhaust fans connected to the chemical hoods to maintain only a slight nega tive pressure in the rooms. At what temperature must the air enter the rooms to maintain 70 F with 0 F outside? Substitute in Equation 2. H = 110,100 + 34,200 = 144,300 Btu per hour; Q = gg X 27,000 = 5400 cfm; t = 70 F; fy = 6Q dQ x Q 2i + 1 = 60 X 0.07495 X 5400 X 0.24 + 70 = 94.7 F. 8 In the preceding question, if the air drops 2 F between the heater and the rooms, how many pounds of steam per hour at 1-lb gage will the heating system condense? Substitute in Equation 15. Q = 5400 cfm; At = 94.7 + 2 = 96.7 F, from solution of Question 7; hfg = 968 Btu, from steam table in Chapter 1. T,, 60 dQ X 0.24 X Af 60 X 0.07495 X 5400 X 0.24 X 96.7 .. . W = ------hj;,-------:------- = -------------------------- ggg------------------------- = 683 lb per hour. 9 The combination hot blast heating and ventilating system for the dining rooms of a hotel is to heat the rooms to 70 F with 0 F outside, and permit the exhaust fan from the adjoining kitchen to draw 5000 cfm from the dining rooms. The transmission losses from the dining rooms total 240,000 Btu per hour. The infiltration into the dining rooms amounts to 1000 cfm from out doors and 1000 cfm from heater rooms. How many cubic feet per minute, measured at 70 F, must be supplied the dining rooms if the air enters at 112 F? First find the infiltration loss by substituting in liquation 1. t = 70 F; to = 0; M0 = d X Q = 0.07495 X 60 X 1000 = 4497 lb per hour. In this case d and Q are figured at 70 F, H0 = 0.24 (t - to) M0 = 0.24 (70 - 0) X 4497 = 75,550 Btu per hour. Next by substituting in Equation 3, find the cubic feet per hour to be circulated. H = sum of transmission and infiltration losses in room = 240,000 + 75,550 = 315,550 Btu per hour; ly = 112 F; ( = 70 F; ,,H 315,500 y " 60 d X 0.24 y - 1) 60 X 0.07495 X 0.24 (112 - 70)10 10 .In.Question 9, 3000.cfm of outside air Vill be drawn in by the supply fan and 3950 cfm will be recirculated. What will be the output of the heating sections in Btu per hour if there is a loss of 2 F between the heaters and the room? ' . The average temperature of the mixture of outdoor and recirculated air-entering the heater JZOO X +J950 X 70 = 39.8 F. Air leaves the heater at 112 + 2 = 114 F. 6950 . Referring to Equation 15, W X Afg = amount of heat required per hour = 60 dQ X 0.24 X Q = 6950 cfm; At = 114 - 39>8 = 74.2 F. H = 60 X 0.07495 X 6950 X 0.24 X 74.2 = 557,000 Btu per hour. \. I 402 Chapter 23 MECHANICAL. WARM AIR FURNACE SYSTEMS Fan Furnaces, Fans and Motors, Elimination of Noise, Air Washers and Filters, Cooling Methods, Duct Design, Controls, Selecting the Furnace, Selecting the Fan, Humidity, Provision for Cooling System, Heavy Duty Fan Furnaces MECHANICAL warm air or fan furnace heating systems, which are a special type of central fan systems, are particularly adapted to residences, small office buildings, stores, banks, schools, and churches. Circulation of air is effected by motor-driven fans instead of by the difference in weight between the heated air leaving the top of the casing and the cooled air entering its bottom, as in gravity systems described in Chapter 24. The advantages of mechanical systems, as compared with gravity systems are: . 1. The furnace can be installed in a corner of the basement, leaving more basement room available for other purposes. 2. Basement distribution piping can be made smaller and can be so installed as to give full head room in all parts of the average basement, or be completely concealed from view except in the furnace room. 3. Circulation of air is positive, and in a properly designed system can be balanced in such a way as to give a greater uniformity of temperature distribution. 4. Humidity control is more readily attained. ' 5. The air may be cleaned by air washers or filters, or both. 6. Some cooling effect in summer will result from the installation of a properly designed system. . 7. The fan and duct equipment may be utilized for a complete cooling and dehumidi- fying system for summer, using either ice, mechanical refrigeration, or low temperature water for: cooling and dehumidifying, or adsorbers for dehumidifying. . 8. The use of the fan increases the volume of air which can be handled, thereby increasing the rate of heat extraction from a given amount of heating surface'and insuring sufficient air volume to obtain proper distribution in a large room. . . Much of the equipment used in centred fan systems is the subject matter of other chapters. It is the purpose of this chapter to discuss the co ordinated design and to deal in detail only with problems not covered elsewhere which refer particularly to the whole problem of fan warm air furnace heating and air conditioning. FAN FURNACES Furnaces for mechanical warm air systems may be made of cast-iron, steel, or alloy.. Cast-iron furnaces are usually made in sections and must be assembled and cemented or bolted together on the job. Steel furnaces are made with welded or riveted seams. The proper design of the furnace ' 403 American Society of Heating and Ventilating Engineers Guide, 1936 depends largely on the kind of fuel to be burned. Accordingly, various manufacturers are making special units for coal, oil and gas. Each type of fuel requires a distinct type of furnace for highest efficiency and. econ omy, substantially as follows: 1. Coal Burning: a. Bituminous--Large combustion space with easily accessible secondary radiator or flue travel. " b. Anthracite or coke--Large fire box capacity and liberal secondary heating surfaces. . 2. Oil Burning: o. Liberal combustion space. b. Long fire travel and extensive heating surface. 3. Gas Burning: a. Extensive heating surface. ' b. Close contact between flame and heating surface. . : A combustion rate of from 5 to 8 lb of coal per square foot of grate per hour is recommended for residential heatfers. A higher combustion rate is Chapter 23--Mechanical Warm Air Furnace Systems be lined with black iron liners, extending from the grate level to the top.of the furnace and spaced from 1 in. to 1^ in- from the outer casing. Casings for commercial or heavy duty furnaces, if built of galvanized iron, should be insulated with fireproof insulating material at least 2-in. thick. It is generally believed that either brick or sheet metal casing should be equipped with baffles to secure impingement of the air to be heated against the heating surfaces.. Brick-furnace casings should be supplied with access doors for inspection. ' For furnace casings sized for gravity flow of air, where a fan is to be used, many manufacturers recommend the use of special baffles to restrict the free area within the casing and to force impingement of the air against the heating surfaces. The method of making these baffles for furnaces with top horse-shoe radiators and for furnaces with back crescent radia tors is illustrated in Fig. 1. ................. . Either square or round casings may be used. Where square casings are used, the corners must be baffled to reduce the net free area and to force impingement of air against the heating surfaces. Fig. 2 shows the usual method of baffling square furnace casings for fan-furnace work. Fig. 1. .. Usual Method of Baffling Round Casings for Fan Furnace Work A. Liner, 1 in. from casing. B. Hole to vent baffle. . C. Baffle, closed top and bottom. D. Outer casing. . . permissible with larger furnaces for buildings other than. residences, depending upon the ratio of grate surface to heating surface, firing period, and available draft. . :. 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. It is recommended that the system be designed for blow-through installations, so that the furnace shall be under external pressure-in order to minimize the possibility of leakage of the products oL combustion into the air circulating system. .^ / In residential furnaces for coal burning, the ratio of heating surface to grate area will average about 20 to 1; in commercial sizes it may run 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 any number of furnaces, using one or more. fans. Casings are usually constructed of galvanized iron, 26-gage or heavier, but they may also be constructed of brick. Galvanized iron casings should 404 Fig. 2. Method of Baffling Square Furnace Casing for Fan Furnace Work 1 A. Baffle, closed top and bottom. . Liner, 1 in. from casing. C. Outer casing. D. Hole to vent baffle. . : The hood or bonnet of the casing above the furnace should be as high as basement conditions will allow, to form a plenum chamber over the top of the furnace.- This tends to equalize the pressure and temperature of the. air leaving the bonnet through the various openings. It is generally, corisidered 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! Fig. 3 illustrates a'coiriplete residence fan furnace installation showing location of fan, furnace, filters, plenum chamber and method of take-off of warm'air pipe. FANS AND MOTORS Centrifugal type fans are most commonly" used, and these may be; equipped with either backward or forward curved blades'.5 Low tip speed is desirable for the elimination of air noise, especially where forward curved blades are used. Motors may be mounted on the fan shaft dr outside of the fan with belt connection. Multi-speed motors or-pulleys 405 : American Society of Heating and Ventilating Engineers Guide, 1936 are desirable to provide a factor of safety and to allow for more rapid circulation for summer cooling. - For additional information on fans and motors, see Chapters 17 and 42. NOISE ELIMINATION Special attention must be given to the problem of noise elimination. The fan housing must not be directly connected with metal, either to the furnace casing or to the return air piping. It is common practice to use canvas strips in making these connections. Motors and their mountings A. Transition fitting. B. Filters. . ' C. Capped opening. ` D. Canvas connection. 'f B. Pulley--3 diam. V-type. . F. Eliminator. G. Solenoid valve. B. Pressure gage. J Water supply. K. Drain. must be carefully chosen for quiet operation. Electrical conduit and water piping must not be fastened to, nor make contact with fan housing. The installation of a fan directly under a cold air grille is not recommended on account of the noise objection. See also Chapiter 18. AIR WASHERS AND FILTERS" - Washers for residence systems may be provided in separate housings to be installed on the, inlet or outlet side of the fan, or they may be integral with the fan construction. They operate at ;water pressures of from 10 to 30 lb and use two or more spray nozzles for washing and, humidification. The sprays should be adjusted to completely cover the air passages. . Washers are usually controlled by solenoid valves wired in parallel with 40,6 Chapter 23--Mechanical Warm Air Furnace Systems the fan motor. The water supply may, in turn, be controlled by a humidity-controlling device located in one of the living rooms, so that the washer will operate at all times when the fan is in operation, unless the relative humidity should rise beyond a desirable percentage. Washers used in connection with commercial or heavy duty plants should be a regulation type of commercial washer. There are many satisfactory types of filters on the market. These include dry filters, viscous filters, oil filters and other types, some of which must be cleaned, some of which must be cleaned and recharged with oil, and some of which are inexpensive and may be discarded when they become dirty, and replaced with new ones. The resistance of a filter must be considered in the design of the system since the resistance rises rapidly as the filter-becomes dirty, thus im pairing the heating efficiency of the furnace, in fact, endangering the life of the furnace itself. Manufacturers' ratings of filters must be carefully regarded, and ample filter area must be provided. Filters must be replaced or cleaned when dirty.- See also Chapter 16. COOLING METHODS Some cooling may be obtained under certain conditions by the use of basement air. A more positive cooling effect may be obtained through air washers where the temperature of the water is sufficiently low (55 F or lower), and where a sufficient volume of water can be provided. Unless the water is below the dew point temperature of the indoor air at the time the washer is started, botii 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 thain 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 is necessary with this type of cooling. It is thoroughly feasible to use ice or mechanical refrigeration in con nection with the fan and duct system for the heating installation, and to cool the building by this method, provided 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 9 and 10. ' Study of these problems sponsored by the American Society of Heating and Ventilating Engineers in cooperation with the National Warm Air Heating and Air Conditioning Association is in progress at the University of Illinois. The following conclusions may be drawn from the studies thus far completed, subject to the limitations.of the conditions under which the tests were run1: . 1. An uninsulated building of ordinary residential type may require the equivalent of three tons of ice in 24 hours on days when .the maximum outdoor temperature reaches 100 F if an effective temperature of approximately 72 deg is maintained indoors. __ .`See A.S.H.V.E. research paper entitled Study of Summer Cooling in the Research Residence at.the University of Illinois, by A. P. Kratz and S. Konzo (A.S.H.V.E. Transactions, Vol. 39, 1933). . / a Unit Room Coolers in the Research Residence, by A. P. Kratz, M. K. Fahnestock, and S. Konzo (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, November, 1934). * 407 of andAmerican Society Heating Ventilating Engineers Guide, 1936 2. The use of awnings at all windows in east, south, and west exposures may result in savings of from 20 to 30 per cent in the required cooling load. 3. The cooling load per degree difference in temperature is not constant but increases 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 com putation, 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 cooling per season is comparatively meaningless. . 6. The results of the tests suggest the use of a fan at night either to provide more comfortable conditions during the following day without provision for cooling, or to reduce the load required for cooling during the following day. Experience has shown that the volume of. air required for cooling, depending upon the climate and the construction of the building, must usually be.from 50 to 100 per cent greater than that required for heating. If the size of the fan is based upon the Summer requirement, its output may be reduced sufficiently to meet winter heating needs. . 7. Attic exhaust fans are becoming popular adjuncts,for night duty. (See Chapter 12.) DUCT DESIGN The ducts may be either round or rectangular. Rectangular ducts should-be as nearly square as possible; the width should not be greater than four times the breadth. The radii of-elbows should be not less than one and one-half times the pipe diameter for round pipes, or the equiva lent round pipe size in the case of rectangular ducts. The ducts or piping may be designed either as a trunk line system or as a system of individual ducts from the furnace casing to each register. The engineering problems incident to the design of a trunk line system are somewhat more difficult than for the individual duct system. The trunk line system is generally a tailor-made job, whereas the individual duct system with which either round or square ducts may be used may fre quently be assembled from stock materials and-thus installed at a con siderable saving. Individual ducts may frequently be grouped to simulate a trunk duct system in appearance: The design of ducts for air flow is described in Chapter 20. - Dampers . ' ' . ;* Suitable dampers are essential to any trunk or individual duct system, as it is virtually impossible to so lay out a system, that it will be absolutely in balance without the use of dampers. Special care must be used in the design of any system to avoid turbulence and to minimize resistance. Sharp elbows, angles, arid offsets should be avoided. See Figs. 1 arid 2, Chapter 20. Three types of. dampers are commonly used in trunk and individual duct systems. Volume dampers are used to completely cut off or reduce the flow through pipes. (See A and B, Fig., 4.) Splitter dampers are used where a branch is taken off from a main trunk. (See C, Fig. 4.) Squeeze dampers are used for adjusting the volume of air flow and resistance through a given duct. (See D, Fig. 4.) It is essential that a damper, be provided for each main or duct branch. A positive locking device should be used with each type of damper. ; 408 Chapter 23--Mechanical Warm Air Furnace Systems Supply and Return Air Registers Supply registers located in the floor are effective, but as they require frequent attention to keep them clean they should be avoided where another effective register location can be found. Unless registers located in the baseboard are well proportioned and designed to harmonize with Fig. 4.;. Three Types of Dampers Commonly Used for Trunk and Individual Duct Systems the trim, they may be Urisightly. Registers which are located in side walls above the baseboard or in the ceiling should be of an effective air-diffusing type. All registers should be sealed against leakage around the borders or margins. Velocities through registers may be reduced by the use of registers larger than the connecting, pipes. Some suggestions for equalizing veloci ties over the face area of the register by means of diffusers are illustrated Fig. 5. Diffusers in Transition Fittings to Equalize Velocities Through Register Faces . : in Fig. 5. Merely to use a larger register may not result in materially reduced velocities unless such diffusers are used. Care should be exercised in making the connection between the supply register and its box to prevent streaking oi the wall. All .warm air registers should be equipped with dampers, or, better, with diffuser dampers which may be used to direct air currents in such a way that they will not be objectionable. (See Chapter 19.) 409 of andAmerican Society Heating Ventilating Engineers Guide, 1936 fc oj g gg<' a HE. < a |e UO <6x ttoo oH to (Ji [NfeJH Bttoo (p5A & P! *,3 X Q -og u2z5 oH a < 5 to 2l<S<5 <QO0 g2g p<58 mK S | Kg'" (2 J SJ d-5 2 tto w-B. to 2O U toS oto <^ tQo ow n <g H< yaUto & X c& 6 Uh 410 Chapter 23--Mechanical Warm Air Furnace Systems CONTROLS Air stratification, high bonnet temperatures, excessive flue gas tem peratures, and heat overrun or lag in the system can be largely elimi nated through proper care in the planning and installation of the control system. The essential requirements of the control are: 1. To keep the fire burning when using solid fuel regardless of the weather. 2. To avoid excessive bonnet temperatures with resultant radiant heat losses into the basement. 3. To avoid the overheating of certain rooms through gravity action during off periods of blower operation. 4. To have a sufficient supply of heat available at all times to avoid lag when the room thermostat calls for heat. 5. To prevent cold air delivery when heat supply is insufficient. 6. To avoid heat loss through the chimney by keeping stack temperatures low. 7. To provide quick response to the thermostat, with protection against overrun. 8. To provide for humidity control. 9. To provide a means of summer control of cooling. 10. To protect against fire hazards. . The following controls are desirable: 1. A thermostat located at a point where maximum fluctuation in temperature can be expected, in order to secure frequent operation of fans, drafts, and burners. This location would be near an outside wall but not upon it, in a sun room, or in a room with some unusual exposure. The thermostat, of course, should not be located where it will be affected by direct radiant heat from the sun or from a fireplace, or by direct heat from any warm air duct or register. 2. A furnacestat located in the bonnet to permit blower operation only between the temperatures of 100 F and 150 F. In certain extreme cases it may be necessary, or weather conditions may make it advisable, to adjust the high limit to a higher tempera ture than that given. Another location sometimes used for the furnacestat is in the main duct near the frame opening from the bonnet. 3. A protective limit control located in the bonnet to shut down the system inde pendently of the thermostat if the bonnet temperature exceeds 225 F. 4. On oil and gas burner installations, a control is usually included which will shut down the system if the fire goes out or if there is a failure of the ignition system. 5. A humidistat to regulate the moisture supplied to the rooms. 6. On automatic stoker installations, a control is usually included which will start. the operation regardless of thermostat settings whenever the bonnet temperature indicates that the fire is dying. . While it is usually all right to start and stop the fan in residential con trol work and in. auditoriums and other places where many people may gather, the fan should as a rule be allowed to run continuously and the control should be cared for in other ways. SELECTING THE FURNACE The following formula may be used to compute the grate area of a residence furnace, assuming a ratio of heating surface to grate area of 20 to 1: H G= FX CXB (1) J of and V 1936American Society Heating entilating Engineers Guide, 412 23--Chapter Mechanical Warm Air Furnace Systems where G = required grate area, square feet. 77 -- total heat loss from building, Btu per hour. T7 -- calorific value of.coal, Btu per pound: C -- combustion rate in pounds of fuel per square foot of grate per hour. E -- furnace efficiency based on heat available at register faces. In practice it is customary to use the following constants: F = 13,000 (For specific values, see Table 1, Chapter 27). C = 5 to 10 lb (Use 8 lb as maximum in residence work). E = 55 per cent to 65 per cent depending on fuel burned. be used with highly volatile solid fuel. .' Lower efficiency must . . .. . . Where ratio of heating, surface to grate area is less or greater than 20 to 1, deduct or add 2 per cent from or to rating of furnace for each unit decrease or increase in ratio, as the case may be. The foregoing procedure' for determining the size of the furnace to be used applies to continuously heated buildings. . Although intermittently heated buildings usually have their heat losses computed according to the standard rules for determining such losses, these rules do not take into account the heat, which will be absorbedby the cold material of.the building after the air is raised in temperature. This heat absorption must be added to the normal heat loss of the building to determine the load which the heating plant must carry through the warming-up process. It is customary to increase the normal heat loss figure by from 50 to 150 per cent depending upon the heat capacity of the construction material, the higher percentage applying to materials of high heat capacity such as concrete and brick. Fan furnace systems are well adapted for heating intermittently heated buildings as these systems do not require the warming of intermediate piping, radiators, or con vectors, the generation of steam, or the heating of hot water. Follow the same methods for an oil furnace as for coal where a con version unit is to be used,, making sure that the ratio of heating surface to grate area exceeds 20 to 1. If it does not, a size larger furnace should be selected. Use the manufacturers' Btu ratings, of furnaces designed for exclusive use with oil, and select a burner with liberal excess capacity. The selection of the proper size gas furnace for a constantly heated; building can be easily made by using the following Atnerican Gas Associa tion formula: where H = total heat loss from building in Btu per hour. R = official A.G.A. output rating of the furnace in Btu per hour. _ In the case of converted warm air furnaces a slightly different procedure is necessary, as the Btu input to the conversion burner must be selected rather than the furnace output* The proper sizing may be done by means of the following formula: I -1.5677 . (3) 413 and 1936American Society o/Heating Ventilating Engineers Guide, where I = Btu per hour input. . , The factor 1.56 is the multiplier necessary to care for a 10 per cent heat loss in the distributing ducts and an efficiency of 70 per cent in the con version burner. SELECTING THE FAN Choose a fan which, according to its manufacturer's rating, is capable of delivering a volume of air, expressed in cubic feet per minute, against a frictional resistance, expressed in inches of water, computed by adding together the following items: 1. The frictional resistance of a warm air trunk or leader. 2. The frictional resistance of a return air trunk or duct. 3. The resistance to the flow of total volume of air through the furnace casing of hood, which is usually considered from 0.10 to 0.15 in. of water. . 4. The frictional resistance through any other accessories, such as washers or filters. 5. A factor of safety of 10 per cent of the resistance calculated above. HUMIDITY Mechanical warm air systems offer an excellent means of proportioning and distributing moisture-bearing air; consequently, during the winter months humidifiers may be employed to deliver water vapor to. the fan- driven air stream in proper amounts to produce a more humid atmos phere, with increased comfort for people and increased life for household furnishings. Temperatures and relative humidities should be govertied within the limits of the generally accepted standards. See Chapters 3 and 11 for more detailed information on this point. . In earlier types of furnaces, water evaporating pans were usually placed in the cool portions of the air stream, but modern types usually locate/ them in air which has been heated by contact with the heating surfaces. To change water into vapor capable of being carried in an air stream as part of the mixture, about 1000 Btu per pound are required. Without the addition of this heat, termed the latent heat of evaporation, water injected into the air will be carried along in the form of tiny globules until it falls out of the stream or is deposited upon some surface. Furthermore, when dry air is in contact with water for a sufficient length of time without the presence of a sizable body of water or.a source other than air from which this latent heat, of evaporation can be taken, such heat is supplied from the air. There is, therefore, a trend in present ' practice toward heating the water in addition to heating the air. Equip ment for doing this may make use of sprays, or it may take the form of water circulating coils placed within the combustion chamber and con nected by pipes to the humidifier pans where a constant water level is maintained by some separate float device. (See Chapter 11.) Humidification for Residences The principles underlying humidity requirements and limitations for residences are summarized in University of Illinois Bulletin No. 48s, as follows: See Humidification for Residences, by A. P. Kratz (University of Illinois, Bulletin No. 48). 414 23--Chapter Mechanical Warm Air Furnace Systems- 1. Optimum comfort is the most tangible criterion for determining the air conditions within a residence. . . 2. An effective temperature of 65 deg1 represents the optimum comfort for the majority of people. Under the conditions in the average residence a dry-bulb tempera ture of 69.5 F with relative humidity of 40 per cent is the most practical for the attain ment of 65-deg effective temperature. 3. Evaporation requirements to maintain a relative humidity of 40 per cent in zero weather depend on the amount of air inleakage to the average residence, and vary from practically nothing to 24 gal of water per 24 hours. 4. Relative humidity of 40 per cent indoors cannot be maintained in rigorous climates without excessive condensation on the windows unless tight-fitting storm sash or the equivalent is installed. 5. The problems of humidity requirements and limitations cannot be separated from considerations of good building construction, and the latter should receive serious atten- , tion in the installation of humidifying apparatus. . 1 The following conclusions were drawn from the experimental results . reported in the aforementioned bulletin: ; X. None of the types of warm air furnace water pans tested proved adequate to , evaporate sufficient water to maintain 40 per cent relative humidity in the Research j . Residence except only in moderately cold weather. 2. The water pans used in the radiator shields tested did not prove adequate to mainj tain 40 per cent relative humidity in a residence similar to the Research Residence when j the outdoor temperature approximated zero degrees Fahrenheit. i. PROVISION FOR COOLING SYSTEM If the system is to be used for cooling, the following provisions should be made: 1. Where cooling is to be secured through air circulation only: a. Provide for an increase of 50 to 100 per cent in fan capacity through multi-speed pulleys or other means. b. If basement air or outside night air is to be used, provide suitable basement 1 opening in duct system, or outdoor air intake. 2. Where water below 55 F or artificial refrigeration or ice is to be used: a. Provide outside air duct for circulation of cool night air for economy. b. Make provision in return duct system for cooling unit. c. Make provision lor control of the fan speed, during wrinter operation, to give a sufficient and draftless air movement. HEAVY DUTY FAN FURNACES Fan furnaces for large commercial and industrial buildings are available in sizes ranging from 400,000 to 3,000,000 Btu per hour per unit. Heavy duty heaters may be arranged in combinations of one or more units in a battery. A few possible arrangements are shown in Figs. 6 to 13, in clusive. Most manufacturers of heavy duty furnaces rate their furnaces in Btu 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 *66 deg Is the optimum winter effective temperature recommended by the A.S.H.V.E. Committee on Ventilation Standards. See Chapter 3. . 415 =5! Ff American Society of Heating and Ventilating Engineers Guide, 1936 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 on 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) regu lating the fuel supply. The design of heavy duty fan furnace heating systems is in many respects similar to that of the central fan heating systems described in Chapter 22. Ducts are designed by the method outlined in Chapter 20. PROBLEMS IN PRACTICE 1 A residence furnace, having a ratio of heating surface to grate area in excess of 20 to 1, is to be selected to heat a house which has a computed load of 225,000 Btu per hour. If coal having a calorific value of 13,000 Btu per lb is to be burned, if the. furnace will.burn 8 lb of coal per square foot of grate per hour, and if the furnace efficiency is 60 per cent, determine the square feet of grate area necessary in the furnace to be selected. . . Substituting in Equation 1: G= 225,000 = 3.6 sq ft of grate area. 13.Q00 X 0.60 X 8 A furnace having at least 3.6 sq ft of grate area should therefore be selected. 2 Why should secondary surface be designed for easy cleaning? If the combustion is not perfect, soot is formed immediately above the. fire and is apt to form a deposit on the secondary surface from which it should be removed. If the secondary surface is so designed that there are horizontal passages, fine gray ash will settle out in these to form an insulation between the hot gases of combustion and the metal of the furnace; consequently, these should be readily cleaned. If the passages are vertical they are largely self-cleaning of ash, but provision should be made for easy and thorough cleaning of the collection chamber below them. 3 Why is baffling inside the casing necessary on fan systems? Because the movement of air is independent of its temperature, air must be guided by baffles of one form or another to bring it in contact with the not surfaces so it will not pass through the casing unheated. On the other hand, if the air is held against a hot surface too long it might become overheated, for the average register temperature on a fan system should not exceed 120 F. , \4 4 What practical points should be observed in designing a fan system in order to eliminate noise? . a. Use a large fan so it can be run at slow speed. ' b. Set the fan and motor on a solid, foundation. '. . c. Insulate the fan and motor from the foundation with rubber-, cork, or other springy material according to the principles given in Chapter 18, provided, of course, that such insulation is of value. _ d. See that the air velocity is not too high in the ducts. Properly designed splitters in the elbows will avoid high velocities at the turns in cases where the velocity through the ducts themselves is riot too high. - - . ' . e. Use canvas connections between the ducts and any running equipment. J. Be sure the ducts have a relatively smooth interior and are rigid. . 416 Chapter 24 . GRAVITY WARM AIR FURNACE SYSTEMS , Procedure for Design, Estimating Heating Requirements, Sizes of Leader Pipes, Proportioning Wall Stacks, Register Sizes, Recircu lating Ducts and Grilles, Return Connection to Furnace, Furnace Capacity, Examples, Booster Fans WARM air heating systems of the gravity type are described in this chapter1, and those of the mechanical type are described in Chapter 23. In the gravity type, the motive head producing flow .depends upon the difference in weight between the heated air leaving the top of the casing and the cooled air entering the bottom of the casing, while in the mechanical type a fan may supply all or part of the motive head. Booster fans are often used in conjunction with gravity-designed systems to increase air circulation. In general, a warm-air furnace heating plant consists of a fuel-burning . furnace or heater, enclosed in a casing of sheet metal or brick, 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 run in the inside partitions of the building are called stacks. The heated air is finally discharged into the rooms through registers which are set in register boxes placed either, in the floor or in the side wall, usually at or near the baseboard. The air supply to the furnace may be taken (1) entirely from'inside the building through one or more recirculating ducts, (2) entirely from outside the building, in which case no air is recirculated, or (3) through a combination of the inside and the outside air supply systems. PROCEDURE FOR DESIGN The design of a furnace heating system involves the determination of the following items: 1. Heat loss in Btu from each room in the building. . 2. Area and diameter in inches of warm-air pipes in basement (known as leaders). 3. Area and dimensions in inches of vertical pipes (known as wall stacks). 4. Free and gross area and dimensions in inches of warm-air registers. - 5. Area and dimensions of recirculating or outside air ducts, in inches. 6. Free and gross area and dimensions in inches of recirculating registers. All figures and much of the engineering data which follow are from Bulletins No. 141, 188 aiid 189, Warm Air Furnaces and Heating Systems. Part II. by Professor A. C. Willard, A. P. Kratz, and V. S. Day; Engineering Experiment Station, University of Illinois. -. 417 American Society of Heating and Ventilating Engineers Guide, 1936 4Chapter 2 --Gravity Warm Air Furnace Systems 7. Size of furnace necessary to supply the warm air required to overcome the heat loss from the building. This size should include square inches of leader pipe area which the furnace must supply. It is also desirable to call for a minimum bottom fire-pot diameter in inches, which is the nominal grate diameter. . 8. Area and dimensions in inches of chimney and smoke pipe. If an unlined chimney is to be used, that fact should be made clear. The heat loss calculations should be made in accordance with the procedure outlined in Chapter 7, taking into consideration the trans mission losses as well as the infiltration losses. SIZES OF LEADER PIPES In a gravity circulating warm-air furnace system the size of the leader to a given room depends upon the temperature of the warm air entering the room at the register. A reasonable air temperature at the registers must, therefore, be chosen before the system can be designed. The National Warm Air Heating and Air Conditioning Association has ap proved an air temperature of 175 F at the registers as satisfactory for design purposes. At this temperature, the heat-carrying capacity (heat available above 70 F) per square inch of leader pipe per hour for first, second or third floors is shown by Fig. 1 at 175 F to be 105, 170 and 208 -Btu, respectively. For average calculations, the values 111, 166 and 200 will simplify the work and may be satisfactorily substituted for 'these heat-carrying capacities. If H represents the total heat to be supplied any room, the resulting equations are: - Leader areas for first floor, square inches = -- = approximately 0.00977 (1) Leader areas for second floor, square inches = ~ = approximately 0.006/7 (2) H zuuLeader areas for third floor, square inches = = approximately 0.005/7 (3) In designing for a lower warm-air register temperature, say 160 F, the factors 111, 166 and 200 become 80, 140 and 166 (Fig. 1 at 160 F),and. the,resulting,,equations are: -` , ^,, Leader areas for first floor, square inches = -ttt = approximately 0.012/7 ; . oU ' (4) Leader areas for second floor, square inches = approximately 0.007/7 (5) " Leader areas for third floor, square inches = H 7^5 = approximately 0.006/7 .. lbb (6) These equations are applicable to straight leaders from 6 to. 8 ft in length. Longer leaders must be very thoroughly covered or else the vertical stacks must be increased in area as discussed under wall stacks. If some provision is not made for these longer leaders, the air tempera- ture may be much lower than anticipated and the room will not be properly heated. . While Fig. 1 takes care of the drop in temperature in straight leaders up to 8 ft in length connected to stacks having about 75 per cent of the 419 American Society of Heating and Ventilating Engineers Guide, 1936 area of the leader, the designer must make allowances for all other conditions. The temperature drop in leaders of various lengths at three different register temperatures is shown in Fig. 2, and should be used to obtain new register temperatures, lower than 175 F, on which to base selections from the curves of Fig. 1, and thereby new constants for Equations 1, 2 and 3. Leader sizes should in general be not less than those obtained by Equations 1 to 3 nor should leaders less than 8 in. in diameter be used. It is not considered good commercial practice to specify diameters except too * :ni i W/th iii constant ii heart mpo , . to necrren or, -cv, i/c/i/tc?.r.o /* >r/ rr \ l III I I AH xtar/rx t req/jten 8-0".to t c boot to L eacters. 7boot ' ' /o Lt t < 4z S' s' `k V tn- /, f/ */ / s & 0.80 S/nq/e tVa// Stack 6 7/7 Le ter Doab/e Hkf/t Stack, tnq/e IVa/t Stack . - 7 ''Doubte /1/a //1 terck / // - ^ 0.70 ! it I TT! 1~ A t/stac'ks COt77C ed '/ft t the best s/na/e watt stack I 0.60 o //f Siiffy fO/n. anet S-/n. Lenafar o.t 0.2 '79s/s. o.3 o._4___i as ae c az as a9 /.o ' katr'o -Stack Area to L eaater Area Fig. 3. Relative Heating Effect of Stacks at Constant Heat - ,. . . Input to Furnace . . ... Note.--Exterior surface of all ducts is bright tin except at joints , . where asbestos^sealing strips are used.. .. in whole inches. rThe tops of all leaders should be at the same elevation as they leave the furnace bonnet, and from this point there should be a uniform up-grade of 1 in. per foot of run in all cases. Leaders over 12 ft in length are to be avoided or should receive very special attention. PROPORTIONING WALL STACKS The wall stack for an upper floor should be made not less than 70 per cent of the area of the leader which has been selected from Fig. 1. So long as the leader is short and straight as was the case for Fig. 1, 420 Chapter 24---Gravity Warm Air Furnace Systems such a practice is probably justified, since the loss (Fig. 3) in capacity occasioned by the smaller stack is not very serious for stacks having areas in excess of 70 per cent of the leader area. For leaders over 8 ft in length or for leaders which are not straight, the ratio of stack area to leader area should be greater than 70 per cent in order to offset the greater temperature losses (Fig. 2) in the longer leader. In gravity circulating systems, this stack to leader area ratio is a very important consideration. Specific data for a great variety of cases are presented in Figs. 4 and 5 and the designer should check the stack to leader com binations with the nearest comparable case as shown in these figures. Any second-floor stack supplying heat to a room whose heat loss is 9,000 Btu or more (see Figs. 4 and 5 which show that high temperatures are necessary if rooms of more than 9,000 Btu requirement are heated by one stack each in 4-in. studding) should be run within 6-in. studded walls or should have multiple stacks. Stack sections, wherever possible, should be changed from the thin rectangular to the more nearly square shape. REGISTER SIZES The registers used for discharging warm air into the rooms should have free or net area hot less than the area of the leader in the same run of piping. The free area should be at least 70 per cent of the gross area of the register. No upper-floor register should be wider horizontally than the wall stack, and it should be placed either in the baseboard or side wall, if this ca.n be done without the use of offsets. First-floor registers may be of the baseboard Or floor type, with the former location preferred. RECIRCULATING DUCTS AND GRILLES . The ducts through which air is returned to the furnace should be designed to minimize friction and turbulence. They should be of ample area, in excess of the total area of warm-air pipes, and at all points where the air stream must change direction or shape, streamline fittings should be employed. Horizontal ducts should pitch at least 3^2 in. per foot upward from the furnace. The recirculating grilles (or registers) should have a free area at least equal to the ducts to which they connect, and their free area should never be less than 50 per cent of their gross area. ~ The location and number of return grilles will depend on the size, details and exposure-of the house. Small compactly built houses may'frequently be adequately served by a single return effectively placed in a central hall. More often it is desirable to have two or more returns, provided, however, that in two-story residences one return must be placed to effectively receive the cold air returning by why of the stairs. ...... 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 grille should be brought as close to the furnace as possible, but if the room has a bay window, French doors, or other large.sources of cooling or leakage of cold air, the grille, should be placed close by, so as to collect the cool air and prevent drafts. When long ducts of this type are employed they must be made 421 of and 1936American Society Heating Ventilating Engineers Guide, oversize and favored in every way. This precaution is particularly important when long ducts and short ducts are used in the same system. 24--Chapter Gravity Warm Air Furnace Systems friction and turbulence, and that they be located to prevent preheating of the air before it reaches the furnace. The long ducts must be oversize, if they are to operate satisfactorily in parallel with short ducts. . Return ducts from upstairs rooms may be necessary in apartments or other spaces closed off or badly exposed. Metal linings are advisable in such ducts. It is important that these ducts be free from unnecessary 422 Cu<H/5 <n DO >2< Ow & o H to o u. Return Connection to Furnace - Circulation is accelerated if the drop to the furnace is through a round inclined pipe with, say, two 45-deg elbows rather than through a vertical drop and two 90-deg elbows. The top of- the shoe should never enter 423 of andAmerican Society Heating Ventilating Engineers Guide, 1936 the casing above the level of the grate, in the furnace. To accomplish this the shoe must be wide. . Tests of six different systems of cold air returns, Fig. 6, made at the University of Illinois2, resulted in the following conclusions: 1. In general, somewhat better room temperature conditions may be obtained by returning the air from positions near the cold walls. 2. Friction and turbulence in elaborate return duct systems retard the flow of air, and may seriously reduce furnace efficiency, and lessen the advantages of such a design. 3. The cross-sectional duct area is not the only measure of effectiveness. Friction and turbulence may operate to make the air flow out of all proportion to the various duct areas. Afa/ ; A/o.2 .' Area ofmat? a/r cEcrcts SSasqt *?. to a// cases A/o.3 Fig. 6. Arrangement of Cold Air Returns for Six Installations FURNACE CAPACITY . The size of furnace should, of Course, be siich as will'p'rovide the necessary air heating capacity, Usually expressed in square inches of leader pipe area, and at tbe same time provide a grate of the proper area to burn the necessary fuel at a reasonable chimney draft. The total leader pipe area required is easily obtained by finding the sum of the . leader, pipe areas as already designated. : The grate area will depend on'several factors of which four are very important. First of all, the air temperature at the register for which the plant has been designed must be determined. Usually, this tempera ture is taken as 175 F. Second in importance is the combustion rate, which must always correspond with the register air temperature, as is shown by reference to a set of typical furnace performance curves (Fig. 7) for a cast-iron circular radiator furnace with a 23-in. diameter grate and 50-in. diameter casing. The conditions shown on these curves which seem to ' 'Investigation of Warm-Air Furnaces and Heating Systems, Part N, by A. C. Willard, A. P. Kratz and V. S. Day (University of Illinois Engineering Experiment Station Bulletin No. 189). . 424 Chapter 24--Gravity Warm Air Furnace Systems: approximate nearest to the 175 F register warm-air temperature are: combustion rate, 7 lb; warm-air register temperature, 173 F; efficiency of the furnace, 58.5 per cent. The third factor is efficiency, which, in turn, is a function of the combustion rate varying with it as shown by the effi ciency curve of Fig. 7. The fourth factor is the heat value per pound of fuel burned, which was 12,790 Btu. This is not shown on the curves since it was constant for all combustion rates. a/s --i--i--i--i--r--i-- Draft to Inches Wafer- 220000 0/0 0^0* f ^200000 20d\ 180 000 Ret '/S/e rr Tenipet-a/oT0' 60 000 X 3MO000 . ... ~~Ccrpa C/fl, - & $ &/20000 | ft/00000 Grc 'te i?/<7/7'e/e."23//7_ Ce7S//7q D.amTer 50 /n * 70 80000 0s'1 "Eicf/ae/?c 60S 50h 45 | /O !2 Comwst/o/? Rate if? Jh per sq ft of Grateper t?r Fig. 7. Typical Performance Curves for a Warm Air Furnace and Installation. . in a Three Story Ten Leader Plant, Operating on Recirculated Air From the relation existing among these factors it is found (Fig. 7) that the capacity of the furnace under test is 147,750 Btu per hour for the total grate, which gives the capacity at the furnace bonnet per square foot of grate as 51,200 Btu and per square inch of grate as 356 Btu per hour. . Suppose it is desired to select a furnace to deliver air to the rooms at a register temperature approximating 160 F rather than 175 F. Referring to the curves, the relation is: combustion rate, 5.5 lb; register warm-air temperature, i60 F; and efficiency of the furnace, 62 per cent. Under this condition the capacity of the furnace at the furnace bonnet per square foot of grate area is 43,200 Btu per hour, and per square inch of grate it is 300 Btu per hour. From these performance values* the grate area for any 425 ~ American Society of Heating and Ventilating Engineers Guide, 1936 Chapter 24--Gravity Warm Air Furnace Systems plant requirement (allowing 20 per cent heat loss between furnace and registers) will be: j2 . Grate area (175 F register temperature), square inches = ^5(. = 0.0034/7 (7) Grate area (160 F), square inches = = 0.0040H (8) Here H = Btu heat loss from the entire house per hour = summation of all room losses Hi + Ht + etc. + the Btu necessary to heat the fresh air, if any, at intake. This fresh air loss in Btu per hour will be approxi mately 1.27 times the cubic feet of air admitted through the intake per hour on a zero day. For systems which recirculate all the air this value will be zero. For systems which have a fresh air intake, controlled by damper, this value might well be approximated, since this loss will probably be reduced to a minimum on a zero day. Assume for such cases that the building loss is increased by 25 per cent, and that there is the usual 20 per cent loss between furnace and registers. It is not always possible to obtain performance curves, and the fol lowing method is suggested as being a close check.. An addition of 2 per dent of the furnace capacity is proposed for each unit that the heating surface to grate area ratio of the furnace exceeds 20. This addition is based on tests made at the University of Illinois, of four types of furnaces having various ratios of heating surface to grate area. Let E = efficiency of the furnace. / = fuel value of the coal, Btu per pound. p = pounds of coal burned per square foot of grate per hour. R = ratio of heating surface to grate area. H = total heat requirements of the house. r- . . ,. Grate area, square inches = 1.2 X 144 H , [ i + o 02 (R -- 20) 1 fr al mSlde air- ^ For coal having a heat value of 12,000 Btu, and a furnace having 60 per cent efficiency, with 6 lb of coal burned per square foot of grate per hour, and 20 sq ft of heating surface for 1 sq ft of grate, this becomes: . . ' 1.2 X 144 H . Grate area, square inches = 0 60 X 12 000 X 6 for aU mslde air> (!0) and for another furnace having 24 sq ft of heating surface for 1 sq ft of grate the expression is Grate area, square inches = o^O X ^.OOO^X 6 [! + 0.02 (24 -20)] (11) The air temperatures at the registers corresponding to the conditions of Equation 11 would be approximately 165 F, and for 175 F and 12,000 Btu the combustion rate would be about 7.5 lb with an efficiency of 57 per cent, using the curves of Fig. 7 as a guide. TYPICAL DESIGN The application of the preceding data to an actual example may be of assistance to the designer. Figs. 8, 9, 10 and 11 represent the plans of 427 a wqpi^A-M Society of Heating and Ventilate Engineer Guide^IQ^ , 428 --j 24Chapter --Gravity Warm Air Furnace Systems the Warm Air Research Residence of the National Warm Air Heating and. Air Conditioning Association erected at the University of Illinois. Leaders, Stacks and Registers. (Direct Method) '. . . Living Room, 1st floor: .' 17,250 -5- 111 = 155 sq in. leader area. See summary, Table, 1; also example under Standard Code4, Art. 3, Basis of Working Rules for Pipes. " Leader diameter = 14 in. Register size .= 155 sq in. net area. Gross area = net area -j- 0.7 = 14 in. X 16 in. Owner's Room, 2nd floor: . ' ' 15,030 -5- 167 = 90 sq in. leader area. See Summary Table; also example under Standard Code4, Art. 3, Basis of Working Rules for Pipei Leader diameter = 11.4, say 12 in. ' Stack area = 0.7 X 90 = 63 sq in. = say 5 in. X 12 in. Register area = 90 sq in. net area. Gross area = net area H- 0.7 = 12 X 12 or 12 in. X 14 in. .. In like manner the leaders, stacks and registers are calculated for each r6om in the house. .. Leaders, Stacks and Registers. (Code4 Method. See Art. 3, Sec. 1, 2, 3) Living Room (Glass = 90, Net wall = 405, Cubic contents = 2405) Leader ( 12 + 60 + 800 / 9 155 sq,n' Register, same as Direct Method. Owner's Room (Glass = 68, Net wall -- 394, Cubic contents = 2275) - Leader= {l2 + 60 + Wj6 = 90sq,n- . . Stack and Register, same as Direct Method. Assuming all air recirculated, the minimum furnace for the plant will be: " Grate area -- 0.0034 X 132,370 = 450 sq in. = 24 in. diameter at 175 F register temperature. (Equation 7) Grate area = 0.0040 X 132,370 == 530 sq in.. = 26 in. diameter at 160 F register temperature. (Equation 8) 1 If provision should be made for certain outside air circulation, then ' increase the building heat loss by, say 25 per cent and obtain by Equation 7 a 27-in. grate and by Equations 8 and 10 a 29-in. grate. Experiments at the University of Illinois5 have shown that the capacity of a'furnace may be increased nearly three times by an adequate'fan,"* *Plans used with permission. Bathroom on third floor not heated. . .' Standard Code Regulating the Installation of Gravity Warm Air Heating Systems in Residences. This code has been sponsored by the National Warm Air Heating and Air Conditioning Association, the National Association of'Sheet Metal Contractors, and the American Society of Heating and Ventilating Engineers: It is recommended that the installation of all gravity warm air heating systems in residences - be governed by the provisions of this code, the eighth edition of which may be obtained from the National. Warm Air Heating and Air Conditioning Association, 50 W. Broad St., Columbus, Ohio. ; `See University of Illinois Eng. ExP. Sta. Bulletin No. 120, p. 129: . 429 / ft American Society of Heating and Ventilating Engineers Guide, 1936 with a constant register or delivery temperature maintained, provided that the rate of fuel consumption can be increased to provide the necessary heat. In other words, the capacity of a forced circulation system is limited by the ability of the chimney to produce a sufficient draft. Table 1. Summary of Data Applied to Warm Air Research Residence . Rooms From Chapter 7 Estimating Heat Losses Btu Heat Losses H Leader Area Sq In. Stack Area Leader . Sq In. .. Diameter 0.7 X LA Inches Stack Size Net Register Size Gross First Floor Living--:--------Dining. . . Breakfast____ Kitchen. Sun____________ Hall and stair Second Floor Owner's .... S'. W. Bed. Bath,,............ N. Bed.______ Third Floor E. Bed. _ .. W. Bed_______ 17250 6810 2300 9210 25710 12570 15030 9800 2450 14800 8220 8220 ______ = 0.00977 155 61 21 83 230 113 = 0.00677 90 59 15 89 = 0.00577 41 41? _ _ ._ _ .... _. 63 41 10 62 29 29 14 9 8 11 or 12 Two 12 12 ___________ ____ _______ ___________ ___________ 14 X 16 8 X 12 8 X 10 12 X 14 Two 12 X 14 12 X 14 11 or 12 5 X 12 9 3)4 X 12 8 3 X 10 11 or 12 5 X 12 12 X 14 8 X 12 8 X 10 12 X 14 8 3 X 10 8 3 X 10 8 X 10 8 X 10 BOOSTER FANS Booster fans often may be arranged to operate when gas or oil burners are running and to stop automatically when the burners shut down. The booster equipment is most effective in increasing output at low operating temperatures. According to tests, efficiencies may be advanced from 60 per cent for gravity to 70 per cent with boosters at low operating tem peratures, but at high operating temperatures gravity and booster efficiencies are almost identical?. ; See University.of Illinois Eng. Exp. Sta. Bulletin No. 141, p. 79. ' '' '' PROBLEMS IN PRACTICE 1 0 What may prohibit the use of a gravity warm .air system in a large house having several exposed1 wings?. - in'a-gravity'warm'air'system, excessive.vertical distances above the furnace cause little trouble in; the design of the Wall stacks, but excessive horizontal distances from the furnace should be carefully considered in the design of the leaders. To work effectively, a gravity warm air system should be balanced and leaders over 12 ft in length should be avoided if possible.' Long leaders', if used, must be of ample size, well pitched, and well iiisulated. Large houses having-exposed wings may require leaders much longer than 12 ft-; infiltration may createsevere back-drafts in the exposed wings; and the basement ceiling height may not be sufficient to allow the leaders to have a pitch of more than one inch per foot. These conditions may make the exposed wings very difficult to heat with a gravity system because of its low air head differentials. . 430 - Chapter 24--Gravity Warm Air Furnace Systems 2 A third-story bedroom has a calculated, heat loss of 12,000 Btu pet hour. a. What size leader pipe should be used for a 175 F register air temperature? b. What size stack? - . c. What size register? 12 000 a. Leader area = = 60 sq in. Use leader with diameter of 9 in. b. Stack area = 0.7 X 60 = 42 sq in. Use stack 3)4 in. by 12 in. . - c. Register gross area = gy = 85.7 sq in. Use register 8 in. by 12 in. 3 The calculated heat loss of a house is 130,000 Btu per hour. Find the grate area required for the furnace under the following conditions: Heating value of coal = 12,500 Btu per lb. Furnace efficiency 55 per cent. Combustion rate 7.5 lb per- sq ft per hour. Ratio of heating surface to grate area of furnace Register temperature = 175 F. Loss between furnace and registers = 20 per cent. ^^ 1.2 X 144 X 130,000 .................. Gratearea = 0760 X 12,500 X 7.5 " 399 5 ^ ,n' 20 to 1. Grate diameter = 22.6 in. Use grate with diameter of 23 in. . 4 If in Question 3 the conditions were the same except that the ratio of heating surface to grate area of furnace was 24 to 1, what size grate would be required for the furnace? Grate area = 1.2 X 144 X 130,000 0.60 X 12,500 X 7.5 X Grate'diameter = 21.7 sq in. Select grate with diameter of 22 in. .1 1 -+- 0.02 (24 - 20) 399.5 1.08 370 sq in. 5 Name the items involved in the design of a furnace heating system. a. Heat loss from each room, Btu. b. Area and dimensions of warm-air pipes in basement, inches. c. Area and dimensions of vertical pipes, inches. d. Free and gross area and dimensions of warm-air registers, inches. e. Area and dimensions of recirculating or outside air ducts, inches. /. Free and gross area and dimensions of recirculating registers, inches. g. Size of furnace necessary to supply the warm air to overcome.the heat loss: h. Area and dimension of chimney and smoke pipe, inches. ' 6 t Discuss the design features of recirculating ducts. , o. Their area should be equal to or greater than that of the supply ducts. b. They should be streamlined, and have a minimum number of turns. c. All runs should be as short as possible.' d. Account should be taken of all cold walls and window areas in determinin'' sizes and positions of return air inlets. e. The return line should be pitched downward toward the furnace. It should be designed to minimize friction. ' /. The top of the shoe or boot should never be above the grate level. 431 X of 1936Av^pir/VN Society HeatingdndVentilating Engineers Guide, 7 Discuss the use of a booster fan. What effect has a booster fan at low -operating temperatures? At high ones? . A booster fan is useful in accelerating the air flow past the surface of a low temperature furnace, where only a small weight differential in the air is created, and in unbalancing a gravity system so flow is established. The first use involves the entire plant, and increases efficiency about 10 per cent with low. temperature .operation; the second involves only- the leaders in which air flow, is accelerated. At high operating tempera tures the difference in weight between warm outgoing air and cool incoming air is great enough to make a booster unnecessary with ordinary gravity systems. \ 432 w 1 Chapter 25 BOILERS Cast-Iron Boilers, Steel Boilers, Special Heating Boilers, GasFired Boilers, Hot Water Supply Boilers, Furnace Design, Heating Surface, Testing and Rating Codes, Output, Efficiency, Selection of Boilers, Connections arid Fittings, Erection, Operation and Maintenance, Boiler Insulation STEAM and hot water boilers for low pressure heating work are built in a wide variety of types, many of which are illustrated in the Catalog Data Section, and are classified as (l) cast-iron sectional," (2)" steel fire tube, (3) steel water tube, and (4) special. CAST-IRON BOILERS . Cast-iron boilers may be of round pattern with circular grate and hori zontal pancake sections joined by push nipples and tie rods, or of rec tangular pattern with vertical sections. The latter type may be either of outside header construction where each section is independent of the other and the water and steam connections are made externally through these headers, or assembled with push nipples and tie rods, in which case the water and steam connections are internal. Cast-iron boilers usually are shipped knocked down to facilitate handr ling at the place.of installation where assembly is made. One of the chief advantages of cast-iron boilers is that the separate sections can be taken into or out of basements and other places more or less inaccessible after the building is constructed. This feature is of importance in making repairs to or replacing a damaged or worn put boiler and should be given consideration in the original selection. Sufficient space should be pro vided in the boiler room for assembling the boiler and for disassembling it' conveniently if repairs are needed. With the outside header type of boiler a damaged section in the middle of the boiler can be removed without disturbing the other sections and sufficient side clearance should be provided for this contingency. .. Capacities of cast-iron boilers range from that required for small residences up to about 18,000 sq ft of steam radiation. For larger loads, cast-iron boilers must be installed in multiplexor a steel boiler must be used. In most cases cast-iron boilers are limited to'worldng pressures of 15 lb for steam and 30 lb for water. Special types are built for hot water supply which will withstand higher local water pressures. STEEL BOILERS Two general classifications may be applied to steel boilers: first, with; . regard to the relative position of water and hot gases, distinguished as fire, ' 433 American Society of Heating and Ventilating Engineers Guide, 1936 tube or water tube; second, with regard to arrangement of furnace and flues, as (1) horizontal return tubular (HRT) boilers, (2) portable (selfcontained) firebox boilers with either water or fire tubes, and (3) water tube boilers of the power type. Fire tube boilers are constructed so that the water available to produce steam is contained in comparatively large bodies distributed outside of the boiler tubes, the hot gases passing within the tubes. In water tube boilers, the water is circulated within the boiler tubes, heat being applied ex ternally to them. The HRT boiler is the oldest type and consists of a horizontal cylin drical shell with fire tubes, enclosed in brickwork to form the furnace and Table 1. Practical Combustion Rates for Small Coal-Fired Heating Boilers Operating on Natural Draft of from Y% in. to Y in. Water3 .. Kind or Goal Sq Ft Ghat* Lb or Coal per 8q Ft Grata per Hour No.l Buckwheat Anthracite Up to 4 5 to 9 10 to 14 15 to 19 20 to 25 3 3M ' 4 5 Anthracite Pea 1 Up to 9 10 to 19 20 to 25 5 5H 6 Anthracite Nut arid Larger Bituminous , .' Up to 4 5 to 9 10 to 14 , 15 to 19 20 to 25 Up to 4 5 to 14 15 and above ,, ., 8 9 10 11 13 9.5 12 15.5 - in this table. in* 15 ea ft than those indicated combustion chamber: All heating surfaces and the interior of the boiler are accessible for both cleaning and inspection. Horizontal return tubular. boilers, especially the larger sizes, should be suspended from structural columns and beams independent of the brick'setting. Small HRT boilers sometimes are supported by brackets resting on the brick setting. Portablefirebox boilers are the more generally used type of steel heating boilers, their outstanding characteristic being the water-jacketed firebox which eliminates virtually all brickwork. They are shipped in one. piece from the factory and come to the job ready for immediate hook-up to piping. They may be of welded or riveted construction and have.either water or fire tubes. Manufacturers' catalogs usually list heating surface as well as grate area. The elimination of brickwork also makes this type the most compact of steel boilers as well as the lowest in first cost. Water tube boilers. For large heating loads water tube boilers are quite frequently Used. They usually require more head room than other types of boilers but require considerably less floor space and make possible a 434 Chapter 25--Boilers much higher rate of evaporation per square foot of heating surface, with . proper setting, baffling and draft. Water tube boilers used for heating purposes are brick set, supported on structural steel columns and have the brick setting encased in an insulated steel housing to prevent air infiltra tion and to minimize heat losses. For large heating loads, at a high rate of evaporation, such boilers should be operated at pressures above 15 lb per square inch with a pressure-reducing valve on the connection to the heating main. : . ' SPECIAL HEATING BOILERS "' A special type of boiler, known as the magazine feed boiler, has .been developed for the burning of small sizes of anthracite and coke. " These are built of both cast-iron and steel, and have a large fuel carrying capacity which results in longer firing periods than would be the case with thestandard types using buckwheat sizes of coal. Special attention mustbe given to insure adequate draft and proper chimney sizes and connections. Oil-burner boiler units, in which a special boiler has been designed with a furnace shaped to meet the general requirements of oil burners or are t specially adapted to one particular burner have been developed by a number of manufacturers. These usually are compact units with the burner and all controls enclosed within an insulated steel jacket. Ample furnace volume is provided for efficient combustion, and- the heating surfaces are proportioned for effective heat transfer. Consequently, higher efficiencies are obtainable than with the ordinary coal fired boiler converted to oil firing. - GAS-FIRED BOILERS Gas boilers have assumed a well-defined individuality. The usual boiler is sectional in construction with a number of independent burners placed beneath the sections. In most boilers each section has its own burner. In all cases the sections are placed quite closely together, much closer than would be possible when burning a soot-forming fuel. The'effort of the designer is always to break the hot gas up into thin streams, so that all particles of the heat-carrying gases can come as close as possible to the heat-absorbing surfaces. Because there is no fuel bed resistance and because the gas company supplies the motive power to draw, in the air necessary for combustion (in the form of the initial gas pressure), draft losses through gas boilers are low. . HOT WATER SUPPLY BOILERS 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-making properties of the water supplied. If water temperatures are maintained below 140 F the life of the heater will be much longer than if higher temperatures are used, owing to decreased scale formation and minimized corrosion below 140 F. Direct water heaters in some cases are designed to burn refuse and garbage. 1 435 American Society of Heating and Ventilating Engineers Guide, 1936 J. Indirect heaters generally consist of steam boilers in connection with heat exchangers of the coil or tube types which transmit the heat from the 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 the heat exchanger. 4. Discoloration of water may be prevented if the water supply comes in contact with only non-ferrous metal. Where a steam heating system is installed, the domestic hot water usually is obtained from an indirect heater placed below the water line of the boiler. FURNACE DESIGN Good efficiency and proper boiler performance are dependent on cor rect furnace design embodying sufficient volume for burning the par ticular fuel at hand, which requires thorough mixing of air and gases at a high temperature with a velocity low enough to permit complete com bustion of all the volatiles. On account of the small amount of volatiles contained in coke, anthracite, and semi-bituminous coal, these fuels can be burned efficiently with less furnace volume than is required for bi tuminous coal, the combustion space being proportioned according to the amount of volatiles present. ' . Combustion should take place before the gases are cooled by the boiler heating surface, and the volume of the furnace must be sufficient for this purpose. The furnace temperature must be maintained sufficiently high to produce complefe combustion, thus resulting in a higher COj content and the absence of CO. Hydrocarbon gases ignite at temperatures^ 1 varying from 1000 to 1500 F. . The question of furnace proportions, particularly in regard to mechani cal stoker installations, has been given some consideration- by various manufacturers' associations. Arbitrary values have been recommended for minimum dimensions, A customary rule-of-thumb method of figuring furnace volumes is to allow leu ft of space fora maximum heat release of 50,000 Btu per hour. This value is equivalent to allowing approxi mately 1 cu ft for each developed horsepower, and it is approved by most smoke prevention organizations. The setting height will vary with the type of stoker. In an overfeed stoker, for instance, all the volatiles must be burned in the combustion chamber and, therefore, a greater distance should be allowed than for an underfeed stoker where a considerable portion of the gas is burrifed while passing through the, incandescent fuel bed. The design of the boiler also may affect the setting height, since in certain types the gas enters the tubes immediately after leaving the combustion chamber, while in others-' it passes over a bridge wall and toward the rear, thus giving a better opportunity for combustion by obtaining a longer travel before entering the tubes. . To secure suitable furnace volume, especially for mechanical stokers or oil burners, it often is necessary either to pit the stoker or oil burner, or 436 . m Chapter 25--Boilers where water line conditions and headroom permit, to raise the boiler on a brick foundation setting. Smokeless combustion of the more volatile bituminous coals is furthered by the use of mechanical stokers. (See Chapter 28.) Smokeless com bustion in hand-fired boilers burning high volatile solid fuel is aided (1) by the use of double grates with down-draft through the upper grate, (2) by the use of a curtain section through which preheated auxiliary air is introduced over the fire toward the rear of the boiler, and (3) by the intro duction of preheated air through passages at the front of the boiler. AH three methods depend largely on mixing secondary air with the partially burned volatiles and causing this mixture to pass over an incandescent fuel bed, thus tending to secure more complete combustion than is pos sible in boilers without such provision. HEATING SURFACE Boiler heating surface is that portion of the surface of the heat transfer apparatus in contact with the fluid being heated on one side and the gas or refractory being cooled on the other side. Heating surface on which the fire shines is known as direct or radiant surface and that in contact with hot gases only, as indirect or convection surface. The amount of heating surface, its distribution and the temperatures on either side thereof influence the capacity of any boiler. Direct heating surface is more valuable than indirect per square foot because it is subjected to a higher temperature and also, in the case of : solid fuel, because it is in position to receive the full radiant energy of the fuel bed. The heat transfer capacity of a radiant heating surface may be as high as 6 to 8 times that of an indirect surface. This is one of the . reasons why the water legs of some boilers have been extended, especially in the case of stoker firing where the extra amount of combustion chamber secured by an extension of the water legs is important. For the same reason, care should be exercised in building a refractory combustion chamber in an oil-burning boiler so as not to screen any more of this valuable surface with refractories than is necessary for good combustion. The effectiveness of the heating surface depends on its cleanliness, its location in the boiler, and the shape .of the gas passages. Investigations1 by the U. S. Bureau of Mines show that: 1. A boiler in'which the heating surface is arranged to give long gas passages of small cross-section will be more efficient than a boiler in which the gas passages are short and of larger cross-section. .. ' 2. The efficiency of a water tube boiler increases as the free area between individual tubes decreases and as the length of the gas pass increases. . 3. By inserting baffles so that the heating surface is arranged in series with respect to the gas flow, the boiler, efficiency will be increased. . The area of the gas passages must not be so small as to cause excessive resistance to the flow of gases where natural draft is employed. Heat Transfer Rates ' Practical rates of heat transfer in heating boilers will average about See U. S. Bureau of Mina Bulletin No. 18. The Transmission of Heat into Steam Boilers. 437 American Society of Heating and Ventilating Engineers Guide, 1936 3300 Btu per sq ft per hour for hand-fired boilers and 4000 Btu per sq ft per hour for mechanically fired boilers when operating at design load When operating at maximum load2 these values will run between 5000 and 6000 Btu per sq ft per hour. Boilers operating under favorable conditions at the above heat transfer rates will give exit gas temperatures that are considered, consistent with good practice. . ; TESTING AND RATING CODES The Society has adopted three solid fuel testing codes, a solid fuel rating code and an oil fuel testing code. A.S.H.V.E. Standard and Short Form Heat Balance Codes for Testing Low-Pressure Steam Heating Solid Fuel Boilers--Codes 1 and 2--(Revision of June 1929)8, are intended to provide a method for conducting and reporting tests to determine heat efficiency and performance characteristics. A.S.H.V.E. Performance Test Code for Steam Heating Solid Fuel Boilers--Code No. 3--(Edition of 1929)' is intended for use with A.S.H.V.E. Code for Rating Steam Heating Solid Fuel Hand-Fired Boilers4. 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 A.S.H.V.E. Standard Code for Testing Steam Heating Boilers Burning Oil Fuel5 is intended to provide 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 Steel Heating Boiler Institute suggests a single number dimensional rating in the S.H.B.I. Code for the Rating of Low-Pressure Heating Boilers by Their Physical Characteristics6. . BOILER OUTPUT Boiler output as defined in A.S.H.V.E. Performance Test Code for Steam Heating Solid Fuel Boilers (Code No. 3) is the quantity of heat available at the boiler nozzle with the boiler normally insulated. It should be based on actual tests conducted in accordance with this code/ This output is usually stated in Btu and in square feet of equivalent heat ing surface (radiation). According to the A.S.H.V.E. Standard Co'de'for., Rating Steam Heating Solid Fuel Hand-Fired Boilers, the performance data should be given in tabular or curve form on the following items for at least five outputs ranging from maximum down to 35 per cent of maxi mum: (1) fuel available, (2) combustion rate, (3) efficiency, (4) draft tension, (5) flue gas temperature. The only definite restriction placed on setting the maximum output is that priming shall not exceed 2 per cent. These curves provide complete data regarding the performance of the: boiler under test conditions. Certain other pertinent information; such as grate area, heating surface and chimney dimensions is desirable also in forming an opinion of how the boiler will perform in actual service. The output of large heating boilers is frequently stated in terms of For definitions of design load and maximum load see pages 439 and 440. . *See A.S.H.V.E. Transactions. Vol. 35, 1929. Also Chapter 44. . = . See A.S.H.V.E. Transactions. Vol. 36, 1930. Also Chapter 44. See A3.H.V.E. Transactions, Vol. 37, 1931. Also Chapter 44. - See Rating of Heating Boilers by Their Physical Characteristics, by C. E. Bronson (A.S.H.V.E. Trans actions, Vol. 36, 1930). 438 Chapter 25--Boilers boiler horsepower instead of in Btu per hour or square feet of equivalent radiation. :' Boiler Horsepower: The evaporation of 34.5 lb of water per hour from and at 212 F which is equivalent to a heat output of 970.2 X 34.5 = 33,471.9 Btu per hour. 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 this same temperature and at atmospheric pressure. It is usually considered that 10 sq ft of boiler heating surface will pro duce a rated boiler horsepower. A rated boiler horsepower in turn can carry a design load of from 100 to 140. sq ft of equivalent radiation. It is apparent, therefore, that 1 sq ft of boiler heating surface can carry a design load of from 10 to 14 sq ft of equivalent radiation, or somewhat more if the boiler is forced above rating. The application of these values is discussed under the heading Selection of Boilers................... BOILER EFFICIENCY ............................. The term efficiency as used for guarantees of boiler performance is usually construed as follows: 1. Solid Fuels. The efficiency of the boiler alone is the ratio of the heat absorbed by the water and steam in the boiler per pound of combustible burned on the grate to the calorific value of 1 lb of combustible as fired. The combined efficiency of boiler, furnace and grate is the ratio of the heat absorbed by the water and steam in the boiler'per pound of fuel as fired to the calorific value of 1 lb of fuel as fired. " 2. Liquid 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 of fuel to the calorific ' value of 1 lb of fuel. 1' Solid fuel boilers usually show an efficiency of 50 to 75 per cent when operated under favorable conditions at their rated capacities! Infor mation on the combined efficiencies of boiler, furnace and burner has resulted from research Conducted at Yale University in cooperation with the A.S.H.V.E. Research Laboratory and the American Oil .Burner Association7. For general information on heating efficiencies see Chapter SELECTION OF BOILERS Estimated Design Load: The load, stated in Btu per hour or equiva lent direct radiation, as estimated by the purchaser for the conditions of inside and outside temperature for which the amount of installed radiation was determined is the sum of the heat emission of the radiation to be actually installed plus the allowance for the heat loss of the connecting piping plus the heat requirement for any apparatus requiring heat con nected with the system (A.S.H.V.E. Standard Code for Rating Steam Heating Solid Fuel Hand-Fired Boilers--Edition of April, 1932). The estimated design load is the sum of the following three items8: . 1- The estimated heat emission in Btu per hour of the connected radiation (direct, indyect or.central.fan) to be installed. .; [See A.S.H.V.E. research papers entitled Study of the Characteristics of Oil Burners and Heating Boilers, by L. E. Seeley and E. J. Tavanlar (A.S.H.V.E. Transactions, Vol. 37, 1931), and A Study of "vVOil. 1o5o?,1tS19^3i2v);Pe** ratioa of .`!' Burners, by'L. E. Seeley arid J. H . P" owers `(A.S.H.V.E. Tr.a.ns.ac.t.io.ns. of lra)A'S,H'V,E' Code of Minimum Requirements for the Heating and Ventilation of Buildings (Edition 439 American Society of Heating and Ventilating Engineers Guide, 1936 2. The estimated maximum heat in Btu per hour required to supply water heaters or other apparatus to be connected to the boiler. 3. The estimated heat emission in Btu per hour of the piping connecting the radiation and other apparatus to the boiler. Estimated Maximum Load: Construed to mean the load stated in Btu per hour or the equivalent direct radiation that has been estimated by the purchaser to be the greatest or maximum load that the boiler will be called upon to carry. (A.S.H.V.E. Standard Code for Rating Steam Heating Solid Fuel Hand-Fired Boilers--Edition of April, 1932.) The estimated maximum loaid is given by8: 4. The estimated increase in the normal load in Btu per hour due to starting up cold radiation. This percentage of increase is to.be based on the sum of Items 1, 2 and 3 and the heating-up factors given in Table 2. Table 2. Warming-up Allowances for Low Pressure Steam and Hot Water Heating Boilers8. b.c Design Load (Representing Summation op Items 1,2, and 3,4 : Btu per Hour Equivalent Square Feet of Radiation^ 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 Up to 420 420 to 840 840 to 2500 2500 to 5000 5000 to 7500 Above 7500 . Percentage Capaott to Add for Warming Up 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 Venti lation 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. '. bSee also Time Analysis in Starting Heating Apparatus, by Ralph C. Taggert (A.S.H.V.E. Transac- , tions, Vol. 19,1913); Report of A.S.H.V.E. Continuing Committee on Codes for Testing and Rating Steam Heating Solid Fuel Boilers (A.S.H.V.E. Transactions, yol. 36. 1930); Selecting the Right Size Heating Boiler, by Sabin Crocker (treating, Piping and Air Conditioning, March. 1932). r This table refers to hand-fired solid fuel boilers. A factor of 25 per cent oyerdesi&n load is adequate when oil or gas are used as fuels. ' <*240 Btu per square foot. - . .. Other things to be considered are: 5. Efficiency with hard or soft coal, gas, or oil firing, as the case may be. 6. Grate area with hand-fired coal, or fuel burning rate with stokers, oil, or gas. 7. Combustion space in the furnace. . 8. Type of heat liberation, whether continuous or intermittent, or a combination of ' both. .. 9. Miscellaneous items consisting of draft available, character of attendance, pos sibility of future extension, possibility of breakdown, headroom in the boiler room- " ] Radiation Load : The connected radiation (Item 1) is determined by calculating the heat losses in accordance with data given in Chapters 5, 6 and 7, and'dividing by 240 to change to square feet of equivalent radiation as explained in Chapter 30. For hot water, the emission commonly used is 150 Btu per square foot, but the actual emission depends on the temperature of the5 medium in the heating units and of the surrounding air. (See Chapter 30.) Although it is customary to use the actual connected load in equivalent square feet of radiation for ^selecting the size of boiler, this connected load usually represents a reserve in heating capacity to provide for infiltration in the various spaces of the building to be heated, which reserve, however, 440 Chapter 25---Boilers is not in use at all places at the same time, or in any one place at all times. For a further discussion of this subject see Chapter 6. . Hot Water Supply Load ' When the hot water supply (Item 2) is heated by the building heating boiler, this load must be taken into consideration in sizing the boiler. The FUEL AVAILABLE, LB. FUEL DEPTH,IN 414 10 SULPHUR MOISTURE BTU PER LB. . 2-66 3.00 13,633 Fig. 1. Typical Performance Curves for a 36-in. Cast-Iron Sectional Steam Heating Boiler, Based on the A.S.H.V.E. Code for Rating Steam Heating Solid Fuel Hand-Fired Boilers . allowance to be made will depend on the amount of water heated and its temperature rise. A good approximation is to add 4 sq ft of equivalent radiation for each gallon of water heated per hour through a temperature range of 100 F. For more specific information, see Chapter 35. Piping Tax (Item 3) ' It is common practice to add a flat percentage allowance to the equivalent connected radiation to provide for the heat loss from bare and covered pipe in the supply and return lines. The use of a flat allowance of 25 per cent for steam systems and 35 per cent for hot water systems is preferable to ignoring entirely the load due to heat loss from the supply 441 . American Society of Heating and Ventilating Engineers Guide, 1936 and return lines, but better practice, especially when there is much bare pipe, is to compute the emission from both bare and covered pipe surface in accordance with data in Chapter 36. With direct radiation served by bare supply and return piping the percentages may be higher than those stated, while in the case of unit heaters where the output is concentrated in a few locations, the piping tax may be 10 per cent or less. ' Warming-Up Allowance The warming-up allowance represents the load due to heating the boiler and contents to operating temperature and heating up cold radiation and piping. (See Item 4.) The factors to be used for determining the allowance to be made should be selected from Table 2 and should be applied to the estimated design load as determined by Items 1, 2 and 3. Performance Curves for Boiler Selection In the selection of a boiler to meet the estimated load, the A.S.H.V.E. Standard Code for Rating Steam Heating Solid Fuel Hand-Fired Boilers recommends the use of performance curves based on actual tests con ducted in accordance with the A.S.H.V:E. Performance Test Code for. Steam Heating Solid Fuel Boilers (Code No. 3), similar to the typical curves shown in Fig. 1. It should be understood that performance data apply to test conditions and that a reasonable allowance should be made for decreased output resulting from soot deposit, poor fuel or inefficient attention. . Selection Based on Heating Surface and Grate Area Where performance curves are not available, a good general rule for conventionally-designed boilers is to provide 1 sq ft of boiler heating surface for each 14 sq ft of equivalent radiation (240 Btu per square foot) represented by the design load consisting of connected radiation, piping tax and domestic water heating load. As stated in the section on Boiler Output, 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 per cent rating on a boiler-horsepower basis. .. Due to the wide variation encountered in manufacturers' ratings for boilers of approximately the same capacity,xit is advisable to check the grate area required for heating boilers burning solid fuel by means, of the following formula: - ' ' -s ' rH ^ 'm where 17 C X F X E . . . KJ G = grate area, square feet. ' '1 H = required total heat output of the boiler, Btu per hour (see Selection of Boifers, p. 439). . . C = combustion rate in pounds of dry coal per square foot of grate area per hciur, depending on the kind of fuel and size of boiler as given in Table 1. F = calorific value of fuel, Btu per pound. E = efficiency of boiler, usually, taken as 0.60. . Example 1. Determine the grate area for a required heat output of the boiler of 442 Chapter 25--Boilers 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 per cent. ., ,,_ 500,000 G 6 X 13,000 X 0.60 10-7 ^ ft The boiler selected should have a grate area not less than that deter mined by Formula 1. With small boilers where it is desired to provide sufficient coal capacity for approximately an eight-hour firing period plus a 20 per cent reserve for igniting a new charge, more grate area may be required depending upon the depth of the fuel pot. Selection of Gas-Fired Boilers Gas-heating appliances should be selected in accordance with factors given in Table 1, Chapter 28, which include an allowance for heating up cold radiation, and for the piping tax. These factors are for thermo statically-controlled systems; in case manual operation is desired, a warming-up allowance of 100 per cent is recommended by the A.G.A. A gas boiler selected by the use of the A.G.A. factors will be the minimum ' size boiler which can carry the load. From a fuel economy standpoint, it may be advisable to seject a somewhat larger boiler and then throttle the gas and air adjustments as required. This will tend to give a low stack temperature with high efficiency and at the same time provide reserve capacity in case the load is underestimated or more is added in the future. Conversions The conversion of a coal or oil boiler to gas burning is simpler than the reverse since little furnace volume need be provided for the proper com bustion of gas. When a solid fuel boiler of 500 sq ft or less capacity is converted to gas burning, the necessary gas heat units should be approxi mately double the connected load. The presumption for a conversion job is that the boiler is installed and probably will not be made larger; therefore, it is a matter of setting a gas-burning rate to obtain best results with the available surface. Assuming a combustion efficiency of 75 per cent for a conversion installation the boiler output would be 2 X 0.75 = 1.5 times the connected load, which allows 50 per cent for piping tax arid pickup. In converting large boilers, the determination of the re quired Btu input should not be done by an arbitrary figure or factor but should be based on a detailed consideration of the requirements and characteristics of the connected load. An efficient conversion installation depends upon the proper size of flue connection. Often the original smoke breeching between the boiler and chimney is too large for gas firing, and in this case, flue orifices can be used, which are-discs provided with an opening of the size for the gas input used in this boiler. The size should be based on 1 sq in. of flue area for each 7500 hourly Btu input. ' If dampers are found in the breeching they should be locked in position so that they will not interfere with the normal operation of the gas burners at maximum flow. In the case of large boiler conversions, auto matic damper regulators proportion the position of the flue dampers to the amount of gas flowing and may be substituted for existing dampers. Generally in residence conversions automatic dampers are not of the ; 443 of andAmerican Society Heating Ventilating Engineers Guide, i936 proportioning type but close the flue during the off periods of the gas burners. -Automatic shutoff dampers'should be located between the backdraft diverter and the chimney flue. Other Considerations in Selection of Boilers As it will usually be found that several boilers will meet the speci fications, the final selection of the boiler may be influenced, by other con siderations, some of which are: 1. Dimensions of boiler. 2. Durability under service. 3. Convenience in firing and cleaning. 4. Adaptability to changes in fuel and kind of attention. . 5. Height of water line. In large installations, the use of several smaller boiler units instead of one larger one will obtain greater flexibility and economy by permitting the operation, at the best efficiency, of the-required number of units according to the heat requirements. .. Boiler rooms should, if possible, be situated at a central point with respect to the building and should be designed for a maximum of natural light. The space'in front of the boilers should be sufficient for firing, stoking, ash removal and cleaning or renewal of flues, and should be at least 3 ft greater than the length of the boiler firebox. A space of at least 3 ft should be allowed bn at least one side of every boiler for convenience of erection and for accessibility to the various dampers, cleanouts and trimmings. The space at the rear of the boiler should be ample for the chimney connection and for cleanouts, and with large boilers die 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. - When steel boilers are used, space should be provided for the removal and replacement of tubes. CONNECTIONS AND FITTINGS The velocity of flow through the outlets df low pressure steam heating boilers'should not exceed 15 to 25 fps if fluctuation of the water line and undue entrainment of moisture are to be avoided. Steam or water outlet connections preferably should'1 be the full- size of the manufacturers' tapping and should extend vertically to the maximum height available above the boiler. For gravity circulating steam heating systems, it is recommended that a Hartford Loop, described in Chapter 32, be utilized in making, the return connection. Particular attention should be given to fitting connections to secure con formity with the A.S.M.E. Boiler Construction.Code for Low Pressure Heating Boilers. Attention is called in particular to pressure gage piping, water gage connections and safety valve capacity, . Steam gages should be fitted with a water seal and a shut-off consisting 444 Chapter 25--Boilers of a cock with either a tee or lever handle which is parallel to the pipe when the cock is open. Steam gage connections should be of copper or brass when smaller than 1 in. I.P.S.9 if the gage is more than 5 ft from the boiler connection, and also in any case where the connection is less than t/2 in. I.P.S. Each steam or vapor boiler should have at least one water gage glass and two or more gage cocks located within the range of the visible length of the glass. The water gage fittings or gage cocks may be direct connected to the boiler, if so located by the manufacturer, or may be mounted on a separate water column. No connections, except for combustion regu lators, drains or steam gages, should be placed on the pipes connecting the water column and.the boiler. If the water column or gage glass is con nected to the boiler by pipe and fittings, a cross, tee or equivalent, in which a cleanout plug or a drain valve and piping may be attached, should be placed in' the water connection at every right-angle turn to facilitate cleaning. The water line in steam boilers should be carried at the level specified by the boiler manufacturer. Safety valves should be capable of discharging all the steam that can be. generated by the boiler without allowing the pressure to rise more than 5 lb above the maximum allowable working pressure of the boiler. This should be borne in mind particularly in the case of boilers equipped with mechanical stokers or .oil burners where the amount of grate area has little significance as to the steam generating capacity of the boiler. 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 tappings. This facilitates cleaning sludge from the bottom of the boiler sections through the large plugged openings. An equivalent clean out 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 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. For further data on pipe connections for steam and hot water heating systems, see Chapters 32 and 33 and the A.S.M.E. 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 up from the inside of the chimney. A thimble or sleeve grout usually is provided where the breeching enters a brick chimney. ' Code, Identification of Piping Systems. 445 andAmerican Society 0/ Heating Ventilating Engineers Guide, 1936 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 always should be read before the assembly or installation of any boiler is started, even though the contractor may be familiar with the boiler. All joints requiring boiler putty or cement which cannot be reached after assembly is complete must be finished as the assembly progresses. The following precautions should be taken in all installations to prevent damage to the boiler: .; 1. There should be provided proper and convenient drainage connections for use if the boiler is not in operation during freezing weather. , 2. Strains on the boiler due to movement of piping during expansion should be prevented by suitable anchoring of piping and by proper provision for pipe expansion and contraction. * '' .. 3. Direct impingement of too intense local heat upon any part of the boiler surface, as with oil burners, should be avoided by protecting the surface with firebrick or other, refractory material. . .. 4. Condensation 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 boilers mechanically fired. Boiler Troubles A complaint regarding boiler operation generally will be found to be due to one of the following: 1. The boiler Jails to deliver enough heat. The cause of this condition may be: (a) poor draft'; (b) poor fuel; (e) inferior attention or firing; (d) boiler too small; (e) improper piping; (/) improper arrangement of sections; (g) heating surfaces covered with soot; and (h) insufficient radiation installed. - . 2. The water line is unsteady. The cause of this condition may be: (a) grease and dirt in boiler; (b) water column connected to a very active section and, therefore, not showing actual water level in boiler; (c) boiler operating at excessive output. ... 3. Water disappears from gage glass. This may be'caused by: (a) priming due to grease and dirt in boiler; (6) too great pressure difference between supply and 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; (e) improper connections between boilers jn 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; (cj outlet con nections of too small area; (<f) excessive rate of output; (e) water level carried higher than specified. . . 5. Boiler is slow in response to operation of dampers. - This may be due to: (a) poor draft due to air leaks into chimney or breeching; (6) inferior fuel; (c) inferior attention; (d) accumulation of clinker,on grate; (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; (c) too low a rate of combustion; (d) too much excess air in firebox causing chilling of gases. ............... 7. Boiler smokes throughfire door. This may be due to: :(o) defective draft in chimney 446 . Chapter 25--Boilers 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; (^ improper reduction in breeching size. . Cleaning Steam 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 piping systems serves as a carrier for sand and dirt, with the result that a scum of fine particles and grease accumulates on the surface' of the water in all new boilers, while heavier particles may settle to the bottom of the boiler and form sludge. These impurities have a tendency to cause foaming, preventing the generation of steam and causing an unsteady water line. . This unavoidable accumulation of oil and grease should be removed by blowing off the boiler as follows: If not already provided, install a surface blow connection of at least 1 in* nominal pipe size with outlet extended to within 18 in. of the floor or to sewer, inserting a valve in line close to boiler. Bring the water line to center of outlet, raise steam pres sure 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 because 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 in a boiler, as given by the boiler manufacturer, should be carefully followed: - .' . It is common practice when starting new installations to discharge heating returns to the sewer during the first week of operation. This prevents the passage of grease, dirt or other foreign matter into the boiler and consequently may avoid the necessity of cleaning the boiler. During the time the returns are being passed to the sewer, the feed valve should be cracked sufficiently to maintain the proper water level in the boiler. Care of Idle Heating Boilers -. Heating boilers are often seriously damaged during summer months due chiefly to corrosion resulting from the combination of sulphur from the fuel 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. ' American Society of Heating and Ventilating Engineers Guide, 1936 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 of some one inadvertently building a fire in a dry boiler, however, it is safer to keep the boiler filled with water. 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 working order. In this connection, oil all door hinges, damper bearings and regulator parts. BOILER INSULATION . Insulation for cast-iron boilers is of two general types: (1) plastic material or blocks wired on, cemented and covered with canvas or duck; and (2) blocks, sheets or plastic material covered with a metal jacket furnished by the boiler manufacturerr' Self-contained steel firebox boilers usually are insulated with block's, cement and canvas, or rock wool, blankets; HRT boilers are brick set and do not require insulation beyond that provided in the setting. It is essential that the insulation on a boiler and adjacent piping be of non-combustible material as even slow-burning- insulation constitutes a dangerous fire hazard in case of low water in the boiler. . . . REFERENCES A.S.H.V.E. Code of Minimum Requirements for the Heating and Ventilation of Buildings. . A.S.H.V.E. Standard and Short Form Heat Balance Codes for Testing Low-Pressure Steam Heating Solid Fuel Boilers (Codes 1 and 2). A.S.H.V.E. Performance Test Code for Steam Heating Solid Fuel Boilers (Code No. 3). A.S.H.V.E. Standard Code for Rating Steam Heating Solid Fuel Hand-Fired Boilers. Heating, Ventilating and Air Conditioning, by Harding and Willard, Revised Edition, 1932. o A.S.M.E. Boiler Construction Code for Low Pressure Heating Boilers. Heating, Piping and Air Conditioning-Contractors National Association Standards (boiler selection tables). . House-Heating, published bV American Gas AssoHation. Handbook of Oil Burning, published by American Oil Burner Association. Heating and Air Conditioning, by Allen and Walker (fourth edition). ' Selecting the Right Size Boiler, by Sabin Crocker (Heating, Piping and Air Con ditioning, February, March, April, 1932). . - PROBLEMS IN PRACTICE 1 What basic requirements of boiler design are to be accomplished with a combination boiler and oil burner unit? Combination units vary widely but in general, the basic requirements of design depends upon a combustion 'chamber of proper design and arranged for the flame shape with adequate heating surface for. the complete combustion of the fuel. 448 Chapter 25--Boilers 2 Name the construction materials that distinguish two types of low pressure heating boilers. a Cast-iron. b. Steel. 3 What is the normal rating range of each type of boiler? a. Cast-iron boilers are rated at from 200 to 18,000 sq ft EDR. b. Steel boilers are rated at from 300 to 50,000 sq ft EDR. . 4 a. What is meant by direct boiler heating surface? b. What is meant by indirect boiler heating surface? . a. Direct boiler heating surface is that boiler surface upon which the fire shines, namely, the walls of the firebox and the crown sheet. .. b. Indirect boiler heating surface is that boiler surface not exposed to the direct rays of the fire and over which heated gases pass after they have been in contact with the direct surface. Indirect surface is generally known as convective surface. 5 What is the average heat transmission rate in heating boilers in Btu per sq ft of heating surface per hour? ' . 3500 for coal burning boilers; 4200 for oil burning boilers. ' 6 What factors contribute to. economical fuel operation in low pressure boilers burning coal or oil? .- '. . a. Proper furnace volume for complete combustion. b. Arrangement of heating surfaces in series to create a turbulent and scrubbing contact of gases against the convective surfaces. ; . .- :; c. Rapid internal water circulation which will remove steam bubbles from the water side of heating surfaces and allow other steam bubbles to. be formed. Rapid disen gagement of steam bubbles increases the steam generating efficiency of each unit' area of heating surface, and thereby lowers flue gas temperatures. .7 What equipment is usually directly attached to a low pressure heating boiler? For coal burning steam boilers: water column, water gage, tri-cocks, steam gage, lever pop safety valve, boiler damper regulator.. For coal burning hot water boilers: damper regulator, altitude gage, thermometer, relief valve. For oil burning boilers, the damper regulators are omitted and the following additional equipment is usually attached: automatic water feeder, low water cutout, a pressure control, and a'water temperature control. These are generally furnished by the oil , burner manufacturer and do not come with the boiler. .\ \ 8 What general precautions regarding the boiler should be taken to make sure a proposed heating installation will work properly? a. Select the right size and type of boiler. b. Be sure the combustion space is proper for the type of fuel burned. c. Allow sufficient space around the boiler for cleaning. d. Secure proper height and area of chimney and connecting breeching. e. Clean the boiler thoroughly and provide surface blowoff connections and bottom blowoff connections for periodic cleaning after operation is begun. /. See that the boiler heating surface is cleaned at regular periods. g. Check flue gas temperatures and make a flue gas analysis at least once a month. h. Secure information and advice from boiler manufacturer. 9 9 Below what temperature should the water in direct water heaters be main tained to reduce scale formation and corrosion? 140 F. 449 " ( ' " ofAmerican Society Heating and Ventilating Engineers Guide, 1936 10 t a. What is the heat equivalent of a boiler horsepower? b- How many square feet of heating surface are usually required per boiler horsepower? a. .33,471.9 Btu per hour. b. 10 sq ft. 11 What is meant by equivalent evaporation? . . The amount of water that a boiler would evaporate per hour, if the feed water were at 212 F and if the steam were evaporated at that temperature; this is usually spoken of as "from and at 212 F." 12 What loads must be considered in determining the boiler capacity re quired for a given installation? Radiation load. Hot water supply load. Piping tax. Warming-up allowance. Load allowance for inefficient firing. 13 A boiler has 6 sq ft of grate area with a possible depth of fuel bed of 18 in. The fuel burned is bituminous coal with a heat value of 12,500 Btu per lb. The efficiency is assumed to be 50 per cent. How great a maximum load .will this boiler carry if it is to be fired every 8 hours and if 20 per cent of the fuel is to be left over to kindle the next charge? Volume of fuel bed = 6 X 1.5 = 9.0 cu ft. Available volume = 0.80 X 9.0 = 7.2 cu ft. Weight of available fuel = 40 X 7.2 = 288.0 lb. Fuel burned per hour = = 35.0 lb. . Heat released 36.0 X 12,500 X 0.50 = 225,000 Btu per hour. Maximum load = 938 equivalent square feet. 14 What are the usual causes of unsteady water line and priming? Grease and dirt in boiler. Overload, resulting in insufficient steam liberating area. Small outlet connections. ' o - - 15 What type of return connection can be used for gravity steam heating systems to make the use of check valves unnecessary? ............ The Hartford Loop. (See Chapter 32.) .. 450 Chapter 26 CHIMNEYS AND DRAFT CALCULATIONS Natural Draft; Mechanical Draft, Characteristics of Natural Draft Chimneys, Determining Chimney Sizes, General Equation, Chimney Construction, Chimneys for Cos Heating THE design and construction of a chimney is so important a part of the heating engineer's work that a general knowledge of draft ~~ characterictics and calculations is essential. ' Draft, in general, may.be defined as the pressure difference between the atmospheric pressure and that at any part of an installation through which the gases_flow. Since a pressure difference implies a head, draft is a static force. While no element of motion is inferred, yet motion in the form of circulation of gases throughout an entire boiler plant installation is the direct result of draft. This motion is due to the pressure difference, or unbalanced pressure, which compels the gases to flow. Draft is often classified into two kinds according to whether it is created thermally or artificially, viz, (1) natural or thermal draft, and (2) arti ficial or mechanical draft. Natural Draft ' Natural draft is the difference in pressure produced by the difference in weight between the relatively hot gases inside a natural draft chimney and an equivalent column of the cooler outside air, or atmosphere. Natural draft, in other words, is ah unbalanced pressure produced thermally by a natural draft chimney as the pressure transformer and a temperature difference. The intensity of natural draft depends, for the most part, upon the height of the chimney above the grate bar level and also the temperature difference between the chimney gases and the atmosphere. A typical natural draft system consists essentially of a relatively tall . chimney built of steel, brick, or reinforced concrete, operating with the relatively hot gases which have passed through the boilers arid accessories and from which all the heat has not been extracted.' Hot gases are an essential element in the operation of a natural draft system, although inherently a heat balance loss. . A natural draft chimney performs the two-fold service of assisting in the creation of draft by aspiration and also of discharging the gases at an elevation sufficient to preverit them from becoming a nuisance. Natural draft is quite advantageous in installations where the total loss of draft due to resistances is relatively low and also in plants which have practically a constant load and whose boilers are seldom operated above 451 American Society of Heating and Ventilating Engineers Guide, 1936 their normal rating. Natural draft systems have been, and are still being, employed in the operation of large plants during the periods when the boilers are operated only up to their normal rating. When the rate of operation is increased above the normal rating, some form of mechanical draft is employed as an auxiliary to overcome the increased resistances or draft losses. Natural draft systems are used almost exclusively in the smaller size plants where the amount of gases generated is relatively small and it would be expensive to install and operate a mechanical draft system. The principal advantages of natural draft systems may be summarized as follows: (1) simplicity, (2) reliability, (3) freedom from mechanical ' Fig. 1. General Operating Characteristics of Typical Induced Draft Fan parts, (4) .low cost of maintenance, (5) relatively long life, (6) relatively low depreciation, and (7) no power required to operate. The principal disadvantages are: (1) lack of flexibility, (2) irregularity, (3) affected by surroundings, and (4) affected by temperature changes. Mechanical Draft . Artificial draft, Or mechanical-draft, as it is more commonly called; is a difference in pressure produced either directly or indirectly by a.forced draft fan, an induced draft fan, or a Venturi chimney as the ..pressure transformer. 'The intensity of mechanical draft is dependent for the most part upon the size of the fan and the speed at which it is operated. The element of temperature does not enter into the creation of mechanical: draft and therefore its intensity, unlike natural draft, is independent of the temperature of the gases and the atmosphere. Mechanical draft includes the induced and Venturi types of draft systems in which the pressure difference is the result of a suction, and also the forced draft system in which the pressure difference is the result of a blowing. Mechanical draft systems tend to produce,a vacuum or a plenum, according as the System used in its production creates a pressure difference below, or above, 452 ' Chapter 26--Chimneys and Draft Calculations Fig. 2. Operating Characteristics of Typical Centrifugal Pump atmospheric pressure, respectively. A mechanical draft system may be used either in conjunction with, or as an adjunct to, a natural draft system. _ CHARACTERISTICS OF CHIMNEYS . In order to analyze the performance of a natural draft chimney, it may be advantageous to compare its general operating characteristics with those of a centrifugal pump and also of a centrifugally-induced draft fan, there being a similarity among the three. Figs. 1, 2 and 3 show the general operating characteristics of a typical centrifugally-induced draft fkri, a typical'centrifugal pump, and a typical natural draft- chimney, respectively.. The draft-capacity curve of the chimney corresponds^ to Fig. 3. Typical Set of Operating Characteristics of a Natural Draft Chimney 453 American Society of Heating and Ventilating Engineers Guide, 1936 the head-capacity curve of the pump and also to the dynamic-head capacity curve of the fan. When the gases in the chimney are stationary, the draft created is termed the theoretical draft. When the gases are flowing, the theoretical intensity is diminished by the draft loss due to friction, the difference between the two being termed the total available draft. The general equation for this net total available draft intensity of a natural draft chimney with a circular section is as follows: Da = 2MHBa 1FC\ ' Tc) 0.00126 W'TcfL DlB0Wc (1) where Da = available draft, inches of water. H = height of chimney above grate bars, feet.. B0 -- barometric pressure corresponding to altitude, inches of mercury. W0 = unit weight of a cubic foot of air at 0 F and sea level atmospheric pressure, pounds per cubic foot. , Wc = unit weight of a cubic foot of chimney gases at 6 F and sea level atmospheric pressure, pounds per cubic foot. T0 = absolute temperature of atmosphere, .degrees Fahrenheit. _ Tc = absolute temperature of chimney gases, degrees Fahrenheit. ; _ W -- amount of gases generated in the combustion chamber of the boiler and passing through the chimney, pounds per second. ' / = coefficient of friction. L = length of friction duct of the chimney, feet. D = minimum diameter of chimney, feet. ' The first term of the right hand expression of Equation 1 represents the theoretical draft intensity, and the second term, the lossdue to friction. Example 1. Determine the available draft of a natural draft chimney 200 ft-iri height and 10 ft in diameter operating under the following conditions: atmospheric' tempera ture, 62 F; chimney gas temperature, 500 F; sea level atmospheric pressure, Ba = 29.92 in. of mercury; 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. .. Substituting these values in Equation 1 and reducing: ^ Da = 2.96 X 200 X 29.92 X 0.09\ 960/ 0.00126 X 100*. X 960 X 0.016 X 200 10s X 29.92 X 0.09 = 1.27 - 0.14 = 1.13 in. Fig. 3 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 ho gases are flowing, the' available draft is equal to 1.27 in. of water, the theoretical intensity. As the amount of gases flowing increases, the available intensity 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 draftcapacity curve corresponds to the head-capacity curve of centrifugal pump characteristics and.the dynamic-head-capacity curve of a fan. The point of maximum draft and zero capacity is called shut-off draft, or point of impending delivery, and corresponds to the point of shut-off head of a centrifugal pump. The point bf zero draft and maximum capacity is .. . 454 Chapter 26--Chimneys and Draft Calculations 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 1 and then plotting the results in the manner shown in Fig. 3. . In substituting the values for the various factors in Equation 1, care should be exercised that the selections be as near the actual conditions as is practically possible. The following notes will serve as a guide for these selections: Fig. 4. Relation Between Barometric Pressure and Altitude 1. The barometric pressure varies inversely as the altitude of the plant above sea level. Fig. 4 gives the barometric pressure corresponding to various elevations as computed from the equation: where . . i = 62,73.7 logio E\ -- altitude of plant above sea level, feet. Do (2) . In general, the barometric pressure decreases approximately 0.1 in. of mercury 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: ., Wc = .0.131 CO + 0.095 Oi + 0.083 AT, . ^ (3) In this equation COs, Ot 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 Wc may be assumed at 0.09. 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. .1 4. The chimney gas temperature does not vary appreciably from the gas temperature as it leaves the breeching and enters the chimney. For average operating conditions, the . chimney gas temperature "will yary. between 500 F and 650 F except in the case when economizers and recuperators are used, when th,e temperature-will vary between 300 F and 450 F. If a chimney has been properly constructed, properly lined and' has no airinfiltration idiie.to open joints, the temperature of the gases throughout the chimney will not differ appreciably from the foregoing figures. In most up-to-date heating plants, the temperature may be read from instruments or ascertained from a pyrometer. The .455 T of andAmerican Society Heating Ventilating Engineers Guide, 1936 analysis of this section is predicated on the assumption of constant gas temperature and no air infiltration throughout the height of the chimney. . .. . : ; 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 conditions in volved. This value, of course, would be less for a new unlined steel stack than for a brick or brick-lined chimney, but in time the inside surface of all chimneys regardless of the materials of construction becomes covered with a layer of soot, and thus the coef ficient of friction has been taken the same for all types of chimneys and in general constant for all conditions of operation. For reasons of simplicity and convenience to Fig. 5. Chimney Performance Chart a To solve a typical example: Proceed horizontally from a Weight Flow Rate point .to intersection with diameter line; from this intersection follow vertically to chimney height line; from this intersection follow horizontally to the right to Available Draft scale. Starting from a point of Available Draft, take steps in reverse order. --- . the reader, this constant value of 0.016 has been employed in the development of the various special equations and charts shown in this chapter. , ! However, much to be recommended as an alternate method is the practise of .separ ately determining duct friction factors as a function of the flow conditions, specifically as a function of the Reynolds number and the relative duct roughness. The Reynolds criterion is based on the physical properties of the gas, the duct dimensions, and the gas velocity. The gas velocity for a chimney is usually well above the critical velocity. It is likely that this procedure of using a separately determined variable friction factor for chimney flow will give results that are to be preferred over those based on a set constant. . . ' 6. The length of the friction duct is the vertical distance between the bottom of the breeching opening and the top of the chimney. Ordinarily this distance is approximately equal to the height of the chimney above the grate level..' . . " . ' . :.. . 456 Chapter 26--Chimneys and Draft Calculations 7. Assuming no air infiltration the amount of gases flowing and being discharged is, of course, equal, to the amount of gases generated in the combustion chamber of the boiler. The total products of combustion in pounds per second for a grate fired boiler may be computed from the equation: . where rp = CgGWty 3600 (4) Cg = pounds of fuel burned per-square foot of grate surface per hour. G = total grate surface of boilers, square feet. .. Cg X G = total weight of fuel burned per ho'ur. . Wtp.= total weight of products of combustion per pound of fuel. A similar computation may be made in the case of gas, oil, or stoker-fired fuel. Fig. 5 is a typical chimney performance chart giving the available draft intensities for various amounts of gases flowing 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 cubic foot, '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 operating conditions, a new chart should be constructed from Equation 1. . - .. ...... . It has been.the usual custom, and still- is to a lamentably greatextent, to select the required size of a nat'uraldraft chimney from a table of chimney sizes based only on boiler horsepowers. After the ultimate horsepower of the projected plant had been determined, the chimney size in The table corresponding to this figure Was then selected as the proper size required. Generally, no further attempt was, made to determine if the height thus selected.was sufficient to help create the required draft demanded by the entire installation, or the diameter sufficiently large to enable the chimney quickly, efficiently, and economically to dispose of the gases. Since the operating characteristics of a natural draft chimqey are similar in,all respects to those of a centrifugal pump, or a centrifugal fan, it'is no more possible to select a proper size chimney from such a table, even with correction factors appended, than it is to: Select the proper size pump from tables based only on the amount of water to be delivered. . DETERMINING CHIMNEY SIZES The required diameter and height of a natural draft chimney are given by the following equations: . H= Dr . (5) where D = 0.288 J WTc " BoWcV - (6) H = required height of chimney above grate bar level, feet. . D = required minimum diameter of chimney, feet (constant for entire height). ' 457 ' American Society of Heating and Ventilating Engineers Guide, 1936 V chimney gas velocity, feet per second. Dt = total required draft demanded by the entire installation outside of the chimney, inches of water. Equations 6 and 6 give the required size of a natural draft chimney with all of the operating factors taken into consideration. Values for all of the factors with the exception of the chimney gas velocity may be either observed or computed. It is, of course, necessary to assume an arbitrary value for the velocity in order to arrive at some definite size. For any one set of operating conditions there will be as many sizes of chimneys as there are values of reasonable velocities to assume. Of the number of sizes corresponding to, the various assumed .velocities, there is one size which will cost least. Since the cost of a chimney structure, regardless of the kind of material used in the construction, varies as the volume of material in the structure, the- cost criterion then may be represented by the approximate equation: . Q = xtHD (7) where Q -- volume of material, cubic feet. t = average wall thickness, feet. For all practical purposes, the value of it/ may be taken as a constant regardless of the size of the structure. Hence, in general, the volume, and consequently the cost, of a chimney structure may be based on the factor HD as a criterion. Therefore, the value of the chimney gas velocity which will result in the least value of HD for any one set of operating con ditions will produce a structure which will be the most economical to use, because its cost will be least. The problem at hand is to deduce an equation for the chimney gas velocity which will result in a combination of a height and a diameter whose product HD will be least. The solution is obtained by equating the product of Equations 5 and 6 to HD, differentiating this product with respect to V and equating the resulting expression to zero. This pro cedure results in the following expression: c. where Ve = economical chimney gas velocity, feet per second. Equation 8 gives the economical,velocity of the chimney gases for any set of operating conditions, and represents the velocity which will result in a chimney the size of which will cost less than that of any other, size as determined by any other velocity for the same operating conditions. After the value of the economical velocity has been determined, the corresponding height and diameter can then be determined from Equa tions 5 and 6, respectively, and the economical size will then be attained.' Equations 5, 6 and 8 may be simplified considerably for average operating conditions in an average size steam plant by assuming typical con-, ditions. 458 Chapter 26--Chimneys and Draft Calculations Average chimney gas temperature, 500 F,,____Tc = 960 'Mean atmospheric temperature, 62 F_____________________Ta - 522 Average coefficient of friction, 0.016-................................................/ = 0.016 Average chimney gas density, 0.09__________________________Wc = 0.09 Sea level elevation, with barometer of 29.92_____...............Ba = 29.92 . Substituting these values in Equations 8, 6 and 5, respectively, and reducing, the results are substantially: Fe = 13.71F1/5 (9) D = 1.5JF2/s (10) H = 1900, (11) Fig. 6. Economical Chimney Sizes2 ^Diameter values also for gas temperatures of 400, 500 and 600 F. Fig. 6 gives the economical chimney sizes for various amounts of gases flowing and for required draft intensities as computed from Equations 9, 10 and 11. They are based on the operating factors used in reducing Equations 5, 6 and 8 to their simpler form. The sizes shown by the curves in the chart should be used for general operating conditions only, or for installations where the required data necessary for an exact deter mination are difficult or impossible to secure. Whenever it is possible to secure accurate data, or the anticipated operating conditions are fairly well known, the required size should be determined from Equations 5, American Society of Heating and Ventilating Engineers Guide, 1936 6 and 8. The recommended minimum inside dimensions and heights of chimneys for small and medium size installations are given in Table 1. GENERAL EQUATION The general draft equation for a steam producing plant may be stated as follows: . Dt -- hi = Af + Ab + /tBd + he + hBr + hv + ho + *E + *R (12) where Dt = theoretical draft intensity created by pressure transformer, inches of water, hf = draft loss due to friction in pressure transformer, inches of water, hp = draft loss through the fuel bed, inches of water, hB = draft loss through the boiler and setting, inches of water, *Br = draft loss through the breeching, inches of water, kv = draft loss due to velocity, inches of water, hBd = draft loss due to bends, inches of water, he = draft loss due to contraction of opening, inches of water, ho = draft loss due to enlargement of opening, inches of water, te = draft loss through the economizer, inches of water. Ar = draft loss through recuperators, regenerators, or air heaters, inches of water. The left hand member of Equation 12 represents the total amount of available draft created by the pressure transformer, that is, the natural draft chimney, Venturi chimney, or fan, and is equal to ,the theoretical intensity less the internal losses incidental to operation. The right-hand member represents the sum of all of the various losses of draft throughout the entire boiler plant installation outside of the pressure transformer itself. The left hand member expresses the available intensity arid is analogous to the head developed by a centrifugal pump in a water works system, while the right hand member expresses the required draft in tensity and is analogous to the total dynamic head in a water works system. For a general circulation of gases where . Pa = D, ; (13) Z?a = available draft intensity, inches of water. Dr = required draft, inches of water. ' _ The draft loss through thefuel bed (hp), or the amount of draft required to effect a given or required rate of combustion, varies between wide limits and represents the greater portion of the required draft. In coal-fired installations, the draft loss through the fuel bed is dependent upon the following factors: (1) character and condition of the fuel, clean or dirty; (2) percentage of ash in the fuel; (3) volume pf interstices in the fuel bed, coarseness of fuel; (4) thickness of the fuel bed, rate of combustion; (5) type of grate or stoker used; (6) efficiency of combustion. ' There is a certain intensity of draft with which the best results will be obtained for every kind of coal and rate of combustion. Fig. 7 gives the intensity of draft, or the vacuum in the combustion chamber required to bum various kinds of coal at various rates of combustion. Expressed in Chapter 26--Chimneys and Draft Calculations Table 1. Recommended Minimum Chimney Sizes for Heating Boilers and Furnaces1 Warm Am Furnace Cafacitt in Sq In. or Leader Pipe Steam Boiler Capacity Sq Ft or Radi ation Hot Water Heater Capacity Sq Ft or Radi ation Nominal Dimen sions or Fire Clay Lining in Inches Rectangular Flub Actual Inside Dimensions of Fire Clay ' Lining io Inches Actual Area Sq Id. Round Flub Inside Dinnv. eter of Tuning in Inches Actual Area Sq In. Height in Ft Above Grate 790 590 973 8^x13 7 xllk 81 1000 690 1,140 10 79 900 1,490 13x13 nKxim 127 900 1,490 8kxl8 6%xl6}4 110 1,100 . 1,820 12 113 1,700 2,800 13x18 11)4 X16M 183 1,940 3,200 15 177 2,130 3,520 18x18 15Mxl5M 248 2,480 4,090' 20x20 17K x 17^ 298 3,150 5,200 18 254 4,300 7,100 20 314 4,600 7,590 20x24 17x21 357 5,000 8,250 24x24 21x21 441 5,570 9,190 24 x 24b 576 5,580 9,200 22 380 6,980 11,500 24 452 7,270 12,000 24 x 28b 672 8,700 14,400 28 x 28b 784 9,380 15,500 .27 573 10,150 16,750 30 x 30b 900 10,470 17,250 28 x 32b 896 35 40 45 50 55 60 65 This table is taken from the A.S.H.V.E. Code of Minimum Requirements for the Heating and Venti lation of Buildings (Edition of 1929). bDimensions are for unlined rectangular flues. other words, these curves represent the amount of draft required to force the necessary amount of air through the fuel bed in order to effect various rates of combustion. It will be noted that the amount of draft increases as the percentage.of volatile matter diminishes, being comparatively low for the lower grades of bituminous coals and highest for the high grades and small sizes of anthracites. Also, when the interstices of the coal are large and the particles are not well broken up, as with bituminous coals, much less draft is required than when the particles are small and are wellbroken up, as with bituminous slack and the small sizes of anthracites. In general, the draft loss through the fuel bed increases as: (1) the per centage of volatile matter diminishes; (2) the percentage of fixed carbon increases; (3) the thickness of the bed increases; (4) the percentage of ash increases; (5) the volume of the interstices diminishes. In making the preliminary assumptions for the draft loss through the fuel bed, due allowances should be made for a possible future change in the grade of fuel to be burned and also in the rate of combustion.- A value should be selected for this loss which will represent not only the highest rate of combustion which will be encountered, but also the grade of coal which has the greatest resistance through the fuel bed and which may be burned at a later date. . , In powdered-fuel and oil-fired installations, there will be no draft loss 461 of andAmerican Society Heating Ventilating Engineers Guide, 1936 through the fuel bed since there is none and, consequently, this factor becomes zero in the general draft equation. All other factors being constant, the height of the chimney in installations of this character will be less than the height in coal-fired installations, and in the case of me chanical draft installations the driving units need not be as large since the head against which the fan is to operate is not as great in the former as in the latter. The draft loss through the boiler and setting (he) also varies between wide limits and, in general, depends upon the following factors: 1. Type of boiler. .2 Size of boiler. 5. Arrangement of baffles. 6. Type of grate. 3. Rate of operation. 7. Design of brickwork setting. 4. Arrangement of tubes. 8. Excess air admitted, . 9. Location of entrance into breeching. Curves showing the draft loss through the boiler are usually based on the load or quantity of gases passing through the boiler, expressed in i ^ Pounds of Coal Burned per Sq.Ft of Grate Surface'per Hr? Fig. 7. Draft Required at Different Rat'es';of Combustion \ for Various Kinds <5f Coal . terms of percentage of normal rate of operation. Owing to the great variety of boilers of different designs and the various schemes of baffling, it is impossible to group together a set of curves for the draft loss through the boiler which may even be Used generally. It is therefore necessary to secure this information from the manufacturer of the particular type of boiler and baffle arrangement under consideration. When a boiler is installed and in operation, the draft loss depends upon the amount of gases flowing through it: This, in turn, depends upon the proportion of excess air admitted for combustion. Primarily, the amount of excess air is measured by the COi content; the less the amount of. C02, the greater the amount of excess air and hence the greater the draft loss. 462 ;* TV Chapter 26--Chimneys and Draft Calculations The loss of draft through the boiler will vary directly as the size of the boiler and the length of the gas passages within. The loss also varies as the number of tubes high, but not in a,direct ratio inasmuch as the loss due to the reversal of flow at the ends of the baffles remains constant regardless of the height of the boiler. The arrangement of the tubes, whether the gases flow parallel to or at right angles to the tubes, has an appreciable effect on the loss. The arrangement of the baffles influences the draft loss greatly, the loss through a boiler with five passes being greater than the loss through one of three or four passes. A poor design and a rough condition of the brickwork will increase the loss greatly, whereas a proper design and a smooth condition will keep the loss at a minimum. The loss through the boiler will be less when the breeching entrance is located at or near the top of the boiler than when it is located at or near the bottom since the gases have a shorter distance to travel in the former instance. The draft loss through the breeching (hsr) is given by the general ! equation: .where 0.000194 W*TcfL A*B0WcCbr (14) W = the amount of gases flowing, pounds per second. Tc = absolute temperature of breeching gases, degrees Fahrenheit. / -- coefficient of friction. L = length of breeching, feet. A = area of breeching, square feet. . B0 = atmospheric pressure corresponding to altitude, inches of mercury. Wc = weight of a cubic foot of breeching gases at 0 F and sea level atmospheric pressure, pounds per cubic foot. Cbr = hydraulic radius of breeching section. ' 1 _ It has been the general custom to lump off the intensity of the breeching loss at 0.10 in. of water per 100 ft of breeching length regardless of its size or shape or the amount and temperature of the gases flowing through it. This practice is hazardous and has no more foundation in fact than that of determining the friction head in a water works system without taking into consideration the size of the pipe or the amount of water flowing through it. When the length of the breeching is relatively short, any variation in any one of the factors in the equation will have no appreciable effect on the draft loss. However, when the breeching is relatively long, the draft loss is affected greatly by the various factors, particularly by the size and shape as well as by the weight of gases flowing. The draft loss due to velocity (hy) is given by the equation Av 0.000194 W*TC ' A'B0Wq (15) and represents the amount of draft required to accelerate the gases from zero velocity to the velocity -at which the gases are flowing, or in other words, from a static gas condition of zero flow to the amount of gases 463 i American Society of Heating and Ventilating Engineers Guide, 1936 flowing throughout the installation. This loss corresponds to the velocity head in water works systems. The draft loss due to bends (hsa) is equivalent to the loss due to the velocity head for a 90-deg bend. In changing direction of flow, the gas velocity decreases to zero with a loss of velocity head and then increases to its proper value at the expense of a loss in pressure head, the net result being a loss in pressure head equal to the velocity head at the bend. This loss is given by the equation: 0.000194 W'TC - - A'BqWq (16). The friction at a right-angle bend is sometimes expressed as the equivalent of a straight length of flue of a certain length for a certain diameter, similar to the procedure used in estimating the loss due to bends in piping systems conducting water.' Most flues, however, par ticularly breechings, are built square or rectangular in section and no general equation based on the shape of the flue can be conveniently expressed. The draft loss due to sudden contraction of an area (he) is given by the equation: ' 0.0001941CcW'irc - . Ac= a\b^w'c (17) where Kc = coefficient of sudden contraction based on the ratio of the areas of the smalle/ to the larger section = 0.5 ^ 1 -- ^ = area of the smaller section. When the flue or passage through which the gases flow is suddenly contracted, a considerable portion of the static head in the larger section is converted into velocity head and a draft loss of some consequence, par ticularly in a short breeching, takes place. A sudden contraction should always be avoided where possible. At times, however, due to obstruc tions or limited head-room, it is necessary to alter the size of the breeching, but a sudden contraction may be avoided by gradually decreasing the area over a length of several feet. The draft loss due to a sudden enlargement of an area (ho) is given by the equation: 0.000194Jfol*r,7c ". ... (18) where K0 = coefficient of sudden enlargement based on -Aj--i , the ratio of the areas of the smaller to the larger section = ^ 1 -- ^ . When the flue or passage through which the gas'es flow is suddenly enlarged, a portion of the velocity head is converted into static head in the larger section and, like the loss due to sudden contraction, a loss of some 464 26Chapter --Chimneys and Draft Calculations consequence, particularly in short breechings, takes place. A sudden enlargement in a breeching may be avoided by gradually increasing the area over a length of several feet. In large masonry chimneys, the area of the flue at the region of the breeching entrance is considerably larger than the area of the breeching at the chimney, and a sudden enlargement exists. ., The draft loss through the economizer (hz) should be obtained from the manufacturer but for general purposes it may be computed from the following general equation: 6.6W2nNTc 10" (19) wjf:here * ' . .' Wa = pounds of gases flowing per hour per linear foot of pipe in each economizer section. N = number of economizer sections. An economizer in a steam plant affects the draft in two ways, (1) it offers a resistance to the flow of gases, and (2) it lowers the average chimney gas temperature, thereby decreasing the available intensity. In the case of a natural draft installation, both of these factors result in a relative increase in the height of the chimney and, in the case of a large plant, they may add as much as 20 or 30 ft to the height. The decrease in the temperature of the gases after they have passed through the economizer has an extremely important effect on the performance of a natural draft chimney and also upon the performance of a fan. CONSTRUCTION DETAILS For general data on the construction of chimneys reference should be made to the Standard Ordinance for Chimney Construction of the National Board of Fire Underwriters. Briefly summarized, these provisions are as follows for heating boilers and furnaces: ' The construction, location, height and area of the chimney to which a heating boiler or warm-air furnace is connected affect the operation of the entire heating system. Most residence chimneys are built of brick and may be either lined or unlined, but in either case the walls must be air-tight and there should be only one smoke opening into the chimney. Cleanout,, if provided, must be absolutely air-tight when closed. . The walls of brick chimneys shall be not (ess than Z% in. thick (width of a standard size brick) and shall be lined with fire-clay flue lining. Fire-clay flue linings shall be manufactured from suitable refractory clay,, either natural or compounded, and shall be adapted to withstand high temperatures and the action of flue gases. They shall be of standard commercial th'ickness, but not less than % in. All fire-clay flue linings shall meet the standard specification of the Eastern Clay Products Association. The flue sections shall be set in special mortar, and shall have the joints struck smooth on the inside. The masonry shall be built around each section of lining as it is placed, and all spaces between masonry and linings shall be completely filled with mortar. No broken flue lining shall be used. Flue lining shall start at least 4 in. below the bottom of smoke- pipe intakes of flues, and shall be continued the entire heights of the flues and project at least 4 in. above the chimney top to allow for a 2 in. projection of lining. The wash or splay shall be formed of a rich cement mortar. To improve the draft the wash surface should be concave wherever practical. . * Flue lining may be omitted in brick chimneys, provided the walls of the chimneys 465 American Society of Heating and Ventilating Engineers Guide, 1936 are not less than 8 in. thick, and that the inner course shall be a refractory clay brick. All brickwork shall be laid in spread mortar, with all joints push-filled. Exposed joints both inside and outside shall be struck smooth. No plaster lining shall be permitted. Chimneys shall extend at least 3 ft above flat roofs and 2 ft above the ridges of peak roofs when such flat roofs or peaks are within 30 ft of the chimney. The chimney shall be high enough so that the wind from any direction shall not strike the top of the chimney from an angle above the horizontal. The chimney shall be properly capped with stone, terra cotta, concrete, cast-iron, or other approved material; but no such cap or coping shall decrease the flue area. There shall be but one connection to the flue to which the boiler or furnace smokepipe is attached. The boiler or furnace smoke-pipe shall be thoroughly grouted into the chimney and shall not project beyond the inner surface of the flue lining. The size or area of flue lining or of brick flue for warm-air furnaces depends on height of chimney and capacity of heating system. For chimneys not less than 35 ft in height above grate line, the net internal dimensions of lining should be at least 7 x 11H in. for a total leader pipe area up to 790 sq in. Above 790 and up to 1,000 sq in. of leader pipe area the lining should be at least ll}i x 11J4 in. inside. In case of brick flues not less than 35 ft in height with no linings, the internal dimensions should be at least 8 x 12 in. up to 790 sq in. of leader area, and at least 12 x 12 in. for leader capacities up to 1,000 sq in. Chimneys under 35 ft in height are unsatisfactory in operation and hence should be avoided. . CHIMNEYS FOR GAS HEATING The burning of gas differs from the burning of coal in that the force which supplies the air for combustion of the gas comes largely from the pressure of the gas in the supply pipe, whereas air is supplied to a bed of burning coal by the force of the chimney draft. If, with a coal-burning boiler, the draft is poor, or if the chimney is stopped, the fire is smothered and the combustion rate reduced. In a gas boiler or furnace such a condition would interfere with the combustion of the gas, but the gas would continue to pass to the burners and the resulting incomplete com bustion would produce a dangerous condition. In order to prevent incom plete combustion from insufficient draft, all gas-fired boilers and furnaces should have a back-draft diverter in the flue connection to'the chimney. A study of a typical back-draft diverter shows that partial or complete chimney stoppage will merely cause some of therproducts of combustion to be vented out into the boiler room, but will not interfere with com bustion. In fact, gas-designed appliances must perform safely under such a condition to be approved by the American Gas Association Laboratory. Otlier functions of the back-draft diverter, are to protect the burner and pilot from the effects of down-drafts, and to neutralize the effects of variable chimney drafts, thus maintaining the appliance efficiency at a substantially constant value. Converted boilers or furnaces, as well as gas-designed appliances, should be provided with back-draft diverters. Since back-draft diverters have a special function to perform in pro tecting gas burning appliances, it is necessary that they should be built to the proper size as shown in Table 2. Work is now in progress on the development of a horizontal diverter for use where there is not enough room to install a vertical type of diverter. Information on the approved proportion of such equipment may be secured from the American Gas Association Testing Laboratory. As is the case with the complete combustion of almost all fuels, the . 466 Chapter 26--Chimneys and Draft Calculations Table 2. Suggested General Dimensions for Vertical Back-Draft Diverter Pipe Size . A B c D 3 3 3 5.5 7.0 4, 4 -4 7.2 9.5 5 5 5 9.4 10.8 6 6 6 11.5 12.0 7 7 7 13.5 13.9 8 8 8 15.5 15.8 9 9 9 17.5 17.5 10 10 10 19.7 18.8 11 11 11 22.2 20.7 12 12 12 24.7 22.2 E 3.8 5.0 5.3 5.6 6.4 7.1 7.7 7.9 8.4 8.7 F- G H I J KLM 0.7 1.0 1.5 1.9 2.3 2.7 3.1 3.6 4.3 5.0 4.4 6.0 8.0 9.8 11.6 13.4 15.2 17.2 19.6 22.0 3.0 4.0 5.0 6.0 7.0 8.0 9.0 10.0 11.0 12.0 1.5 2.0 2.3 2.5 2.9 3.2 3.5 3.8 4.1 4.4 2.5 3.5 4.0 4.5 5.3 6.0 6.7 7.3 8.0 8.5 0.7 1.0 0.9 0.8 0.9 1.0 1.0 1.0 1.5 1.7 1.5 2.3 2.0 3.0 2.4 3.5 2.7 4.0 3.1 4.6 3.5 5.3 4.0 5.8 4.3 6.2 4.6 6.6 5.0 7.0 products of combustion for gas are carbon dioxide (CO,) and,water vapor with just a trace of sulphur trioxide (S03). Sulphur usually bums to the trioxide in the presence of an iron oxide catalyst. The volume of water vapor in the flue products is about twice the volume of the carbon dioxide when coke oven or natural gas is burned. Because of the large quantity of water vapor which is formed by the burning of gas, it is quite important that all gas-fired central heating plants be connected to a chimney having a good draft. Lack of chimney draft causes stagnation of the products of combustion in the chimney and results in the condensation of a large amount of the water vapor. A good chimney draft draws air into the chimney through the openings in the back-draft diverter, lowers the dew point of the mixture, and reduces the tendency of the water vapor to condense. The flue connections from a gas-fired boiler or furnace to the chimney should be of a non-corrosive material. In localities where the price of gas requires the use of highly efficient appliances, the material, used for the flue connection not only should be resistant to the corrosion of water, 467 . American Society of Heating and Ventilating Engineers Guide, 1936 Table 3. Minimum Round Chimney Diameters for Gas Appliances (Inches) Height or Gas Consumption m Thousands or Btu peb Hour Chxunet Fezt 100. 200 300 400 500 750 i 1000 1500 2000 20 4.50 5.70 6.60 7.30 8.00 9.40 10.50 12.35 13.85 40 4.25 5.50 6.40 7.10 7.80 9.15 10.25 12.10 13.55 60 4.10 5.35 6.20 6.90 7.60 8.90 10.00 11.85 13.25 80 4.00 5.20 6.00 6.70 7.35 8.65 9.75 11,50 12.85 100 3.90 . 5.00 5.90 6.50 7.20 8.40 9.40 11.00 12.40 but should resist the corrosion of dilute solutions of sulphur trioxide in water. Sheet aluminum, as well as some other materials, seems to serve this purpose very well. - . ,' When condensation in a chimney proves troublesome, it may be necessary to provide a drain to a dry well or sewer. The cause of the excessive condensation should be investigated and remedied if possible. This may be done by raising the flue temperature slightly or increasing the size of the back-draft diverter. The protection of unlined chimneys has been investigated and the results indicate that after the loose material has been removed, the spraying with a water emulsion of asphalt- chromate provides an excellent protection. A chimney for a gas-fired boiler or furnace should be constructed in accordance with the principles applicable to other boilers. Where the wall forming a smoke flue is made up of less than an 8-in. thickness of brick, concrete, or stone, a burnt fire clay flue tile lining should be used. Care should be used that the lengths of flue tile meet properly with no openings at the joints. Cement mortar should be used for the entire chimney. Table 3 gives the minimum cross-sectional diameters of round chim neys (in inches) for various amounts of heat supplied to the appliance, and for various chimney heights. This is in accprdance with American Gas Association recommendations. ' PROBLEMS IN.PRACTICE 1 What are the principle factors influencing the intensity of natural draft? The intensity of natural; draft depends largely upon the height of chimney above the grate bar level and the temperature difference between the chimney gases and the atmosphere. . .- - . 2 What two kinds of draft need be considered? . Natural draft caused by temperature differences, and artificial draft caused by me chanical forcing. . 3 B What is the effective height of a chimney? . The height from the grate level to the top of the chimney is the effective height in pro ducing natural draft; . 468 Chapter 26--Chimneys and Draft Calculations 4 What dual purpose does a tall chimney fulfill? A tall chimney primarily creates the necessary draft to move the air required for the. combustion process and to move the products of combustion, and secondarily it dis charges the gases at a high elevation to prevent them from becoming a nuisance. 5 a. Name the principal advantages of natural draft. b. Name the principal disadvantages of natural draft. a. Simplicity, reliability, freedom from mechanical parts, low cost of maintenance, relatively long life, relatively low depreciation, operation with no power requirement. b. Lack of flexibility, irregularity, dependence on surroundings, susceptibility to tem perature changes. . . 6 # How is mcchaiiic.nl draft created? By forced draft, by induced-draft fans, or by a Venturi chimney. . 7 Distinguish between theoretical and available draft. Theoretical draft is the difference in pressure inside and outside the base of a chimney when it is under operating temperatures but when there are no gases flowing. Available draft is less than theoretical draft by the friction loss due to the flow of gases through the chimney. 8 Explain the term efficiency of a natural draft chimney. The efficiency of a chimney is the ratio of the work it does in moving gases to the theo retical amount of power it generates. 9 How is the available draft used in a heating plant? . The available draft at the base of the chimney is used to overcome the loss in pressure through the grate, the fuel bed, the boiler passes, the breeching. 10 What arfe some of the factors that influence the draft loss through the fuel bed? , Uniformity and size of coal, the amount of ash mixed with the fuel on the grate, thickness of fuel bed, rate of combustion, amount of air supply as related to the coal burning rate. 11 How does the volatile matter content affect the draft loss through the fuel The higher the volatile content and the lower the fixed carbon content, the lower the draft loss. _ . 12 In what cases will there be no fuel bed draft loss? In oil, gas, and powdered fuel firing the fuel is mixed and burned in suspension; con sequently, no measurable resistance is encountered in the combustion zone. 13 Is it possible to state an. average value for the draft loss through a boiler and its setting? ' .. No. The draft loss varies widely and depends on many factors such as the size and type of gas passageways. The manufacturer is usually able to supply such information. 14 Of what significance is the C02 content of stack gases in establishing draft loss? .. ` e The C02 content of the exit gases is a measure of the completeness of the combustion and the amount of excess air supplied. Low C02 indicates a high excess of air and hence a high draft loss. 469 American Society of Heating and Ventilating Engineers Guide, 1936 15 What two effects does an economizer have on the draft loss? An economizer offers resistance to the flow of gases over the added surfaces; it lowers the temperature of the gases going to the chimney and therefore decreases the available draft. This decrease often necessitates the addition of forced draft. 16 What main provisions should be considered in good chimney construction? Chimneys should be air-tight and connected to only one smoke opening. The chimney top should be high enough above surroundings so the wind will not strike it at any angle above the horizontal. Chimney walls should be not less than one brick in width, and they should be lined with fire clay tile of the size required for the attached heating unit; Tile lining sizes are stated as outside dimensions; therefore, their effective dimensions are less by the thickness of the wall. . '. 17 What is the purpose of a back draft diverter as used on gas burning units? Since the fuel is supplied under pressure independent of draft it is necessary to free the unit from the variable chimney draft and to supply air for combustion in direct propor tion to the supply of fuel gas. The back draft diverter protects the pilot and burners from down drafts. Chapter 27 FUELS AND COMBUSTION 1 Classification of Coal, Airfor Combustion, Draft Required, Com .. bustion of Anthracite, Firing Bituminous Coal, Burning Coke, Hand Firing, Classification and Use of Oil, Classification and . Use of Gas THE choice of fuel for heating is a question of economy, cleanliness, fuel availability, operation requirements, and control. The principal fuels to be considered are coal, oil, and gas. . COAL The complex composition of coal makes it difficult to classify it into clear-cut types. Its chemical composition is some indication but coals having the same chemical analysis may have distinctly different burning characteristics. Users are mainly interested, in the available heat per pound of coal, in the handling and storing properties, and in the burning characteristics. A description of the relationship between the qualities of coals and these characteristics requires considerable space; a treatment applicable to heating boilers is given in U. S. Bureau of Mines Bulletin 276. A classification of coals is given in Table 1, and a brief description of the kinds of fuels is given in the following paragraphs^ but it should be recognized 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 very little dust in handling. It is comparatively hard to ignite but it burns freely, when well started. It is non-caking, it burns uniformly and smokelessly with a short flame, and it requires little attention to the fuel beds between firings. It is capable of giving a high efficiency in the common types of hand-fired furnaces. Semi-anthracite has a higher volatile content than anthracite, it is not as hard and ignites somewhat more easily; otherwise its properties are similar to those of anthracite. 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 prop erties increase as the volatile matter increases, but the coke formed is relatively weak. Having only half the volatile matter content of the more abundant bituminous coals it can be burned with less production of smoke, and it is sometimes called smokeless coal. 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 completely melt, 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 and non-friable enough to permit of the screened sizes being delivered free from fines. In general, they ignite 471 ofAmerican Society Heating arid Ventilating Engineers Guide, 1936 easily and burn freely; the length of flame varies with different coals, but it is long. Much smoke and soot are possible especially at low rates of burning. Sub-bituminous coals occur in the western states; they are high in moisture when mined and tend to break up as they dry or when exposed to the weather; they are liable to ignite spontaneously when piled or stored. They ignite easily and quickly and have 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. Lignite is of woody structure, very high in moisture as mined, and of low heating value; it is clean to handle. It has a.greater tendency than the sub-bituminous coals to disintegrate as it dries, and it also is more liable to spontaneous ignition. Freshly mined lignite, because of its high moisture, ignites slowly. It is non-caking. The char left after the moisture and volatile matter are driven off burns very easily, like charcoal. The lumps tend to break up in the fuel bed and pieces of char falling into the ash pit continue to burn. Very little smoke or soot is formed. Coke is produced by the distillation of the volatile matter from coal. The type of coke depends oh the coal or mixture-of coals used, the temperatures and time of distil-.- lation and, to some extent, on the type of retort or oven; coke is also produced as a residue from the destructive distillation of oil. , ' Table 1. Classification of Coals by Rank/ Legend: F.C. = Fixed Carbon. V.M. = Volatile Matter. Btu = British thermal units. Class Group Limits op Fixed Carbon or Btu Mineral-Matter-Frbb Basis .Requisite Physical Properties 2. Anthracite............ ......... ....... . I. Anthracite_____ Dry F.C., 98 per eent or more (Dry V.M., 2 per cent or less) Dry F.C., 92 per cent or more and leas than 98 per cent (Dry V.M., 8 per cent or Iras and more than 2 per cent) Dry F.C., 86 per cent or more and less Non-agglutinating* than 92 per cent (Dry V.M., 14 per cent or less and more than 8 per cent) II: Bituminous6___ 1. Low volatile bituminous coal_1. Dry F.C., 77 per cent or more and leas than 86 per cent (Dry V.M., 23 per cent or less and more than 14 per cent) .. 2. Medium volatile bituminous coal Dry F.C., 69 per cent or more and leas than 77 petk- cent (Dry V.M., 31 per cent or less and more than 23 per - cent) ,- 3. High volatile A bituminous coaL Dry F.C., less than 69 per cent (Dry V.M., more than 31 per cent); and moist6 Btu, 14,000^ or more 4. High volatile B bituminous coaL Moist6 Btu, 13,000 or more and leas than 14/000* g ' 5. High volatile C bituminous coaL Moist Btu, 11,000 or more and less Either agglutinating than 13,000* . . - or non-weathering* IIL 8ub-tituminous_ Both weathering and than 13,000* . ' non-agglutinating - Moist Btu\9500 o'r more and less than 11,000* ` . than 9500* ` IV. Lignitic----------- 1 Moist Btu less' than 8300 Consolidated Unconsolidated - aIf agglutinating, classify in low-volatile group of the bituminous class. 6Moist Btu refers to coal containing its natural bed moisture but not including visible water on the surface of the coal. .. .. `Pending.the report of the Subcommittee on Origin and Composition and Methods of Analysis,-it is recognized that there may be non-caking varieties in each group of the bituminous class. *Coals having 69 per cent 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, agglutinating and non-weathering; Variety 2, agglutinating ami weathering; Variety 3, uon-agglutinating and non-weathering. . 'Adapted from A.S.T.M. Standards on Coal and Coke, p. 68, American Society for Testing Materials, Philadelphia, 1934: 472 -.1 .i fii 27--Chapter Fuels and Combustion High-temperature cokes. Coke as usually available is of the high-temperature type, and contains between .1 and 2 per cent volatile matter. High-temperature cokes are sub divided 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 the more easily. 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 develop ment have contained from 10 to 15 per cent 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-temperature cokes because of the differences in the quantities of volatile matter and because some may be light and others briquetted. 1 The sale of petroleum cokes for domestic furnaces has been small and is generally confined to the Middle West. They 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. In order to obtain perfect Combustion a definite amount of air is re quired,for each pound of fuel fired. A deficiency of air supply will result in combustible product's passing to the stack unburned. An excess of air absorbs heat from the products of combustion and results in a greater loss of sensible heat to the stack. Total Air Required. The theoretical amount of air required per pound of fuel for perfect combustion is dependent upon the analysis of the fuel; Table 2. Pounds of Air per Pound of Fuel as Fired - Anthracite 9.6 Cose 11.2 Semi-Bituminous 11.2 Bituminous 10.3 Lignite 6.2 however, for estimating purposes the theoretical air required for different grades of fuel may roughly be taken from Table 2. An excess of about 50 per cent over the theoretical amount is considered good practice under usual operating conditions. The amount of excess air, based upon the laws of combustion, can be determined by its relation to the percentage of COi (carbon dioxide) in the products of combustion. This relationship is shown by the curves (Fig. 1) for high and low volatile coals and for coke. In hand-fired fur naces with long periods between firings the combustion goes through a cycle in each period and the quantity of excess air present varies. Secondary Air-. .The division of the total into primary and secondary air necessary to produce the same rate of burning and the same excess air depends on a number of factors which include size of fuel, depth of. fuel bed, and diameter of fire pot. The ratio of the secondary to the primary air increases with decrease in the size of the fuel pieces, with increase in the depth of the fuel bed, and with increase ini the area of the fire pot; the ratio also increases with increase in rate of burning. Size of the fuel is a very important factor in fixing the quantity of secondary air required for non-caking coals. With caking coals it is. not American Society of Heating and Ventilating Engineers Guide, 1936 Fig. 1. Relation Between COj and Excess Air in Gases of Combustion so important because small pieces fuse together and form large lumps. Fortunately a smaller size fuel gives more resistance to air flow through the fuel bed and thus automatically causes a larger draft above the fuel bed, which draws in more secondary air through the same slot openings. In spite of this, a small size fuel requires a larger opening of the door slots; for a certain size for each fuel no slot opening is required, and for larger.sizes too much excess air gets through the fuel bed. It is impossible to establish a single rule for the correct slot opening for all types and sizes of fuels and for all rates of burning. Furthermore, the Fig. 2. Relative Amount of Fire Door Slot Opening Required in a Given Furnace to Give Equally Good Combustion for High Temperature Coke of Various Sizes When Burned at Various Rates 474 27Chapter --Fuels and Combustion . size of slot opening is dependent on whether the ashpit damper is open or closed. It is better to have too much than too little secondary air; the opening is too small if there is a puff of flame when the firing door is opened. Fig. 2, taken from the U. S. Bureau of Mines Report of Investigations No. 2980, shows the relationship of the slot opening, for a domestic fur nace, to the size of coke and the rate of burning; these openings are with the ashpit damper wide open, and would be less if the available draft permits of its being partly closed. The same openings are satisfactory for anthracite. Bituminous coals require a large amount of secondary air during the period subsequent, to a firing in order to consume the gases and to 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. The following suggestions will be helpful: 1. In cold weather, with high combustion rates, the secondary air damper should be half open all the time. 2. In very mild weather, with a very low combustion rate, the secondary air damper should be closed all the time. 3. For temperatures between very, mild and very cold, the secondary air damper should be in an intermediate position. 4. For ordinary house operation, secondary air is needed after each firing for about one hour. . Draft Required The draft required to effect a given rate of burning the fuel as measured at the smokehood is dependent on the following factors: 1. Kind and size of fuel. ' 2. Combustion rate per square foot of grate area per hour. 3. Thickness of fuel bed. . 4. Type and amount of ash and clinker accumulation. 5. Amount of excess air present in the gases. 6. Resistance offered by the boiler passes to the flow of the gases. 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 by adjustment of the dampers. The quantity of excess air present has a marked effect on the draft required to produce a given rate of burning, and it is often possible to produce a higher rate by increasing the thickness of the fuel bed. Combustion of Anthracite1 An anthracite fire should never be poked, as this serves to bring ash to the surface of the fuel bed where it melts into clinker. .. Egg size is suitable for large firepots (grates 24 in. and over) if the fuel lSee reports published by The Anthracite Institute Laboratory, Primos, Pennsylvania. 475 1 American Society of Heating and Ventilating Engineers Guide, 1936 can be fired at least 16 in. deep. The air spaces between the pieces of coal are large, and for best results this coal should be fired deeply. Stove size coal is the proper size of anthracite for many boilers and furnaces used for heating buildings. It burns well on grates at least 16 in. in diameter and 12 in. deep. The only instructions needed for burning this type of fuel are that the grate should be shaken daily, the fire should never be poked or disturbed, and the fuel should be fired deeply and uniformly. Chestnut size coal is in demand for firepots up to 20 in. in diameter, with a depth of from 10 to 15 in. . Pea size coal is often an economical fuel to burn. It is relatively low in price. When fired carefully, pea coal can be burned on standard grates. It is well to have a small amount of a larger fuel on hand when building new fires, or when filling holes in the fuel bed. Care should be taken to shake the grates only until the first bright coals begin to fall through the grates. The fuel bed, after a new fire has been built, should be increased in thickness by the addition of small charges until it is at least level with the sill of the fire door. This keeps a bed of ignited coal in readiness against the time when a sudden demand for heat shall be made on the heater. Pea size coal requires a strong draft and therefore the best results generally will be obtained by keeping the choke damper open, the coldair check closed, and by controlling the fire with the air-inlet damper only. Pea size can also be fired in layers with stove or egg size anthracite and its use in this manner will reduce the fuel costs and attention required. Buckwheat size coal for best results requires more attention than pea size coal, and in addition the smaller size of the fuel makes it more difficult to burn on ordinary grates. Greater care must be taken in shaking the grates than with pea coal on account of the danger of the fuel falling through the grate. In house heating furnaces the coal should be fired lightly and more frequently than pea. coal. When banking a buckwheat coal fire it is advisable after coaling to expose a small spot of hot. fire by putting a 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 an explosion of gas within the firepot, 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. A good draft is required and consequently the fire is best controlled by the air-inlet damper only. 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. .; 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 uniform low fire will minimize the clinker formation and keep the clinker in an easily broken up condition so that it readily can be shaken through the grate. .. Forced draft and special grates or retorts frequently are used .with this fuel for best results. 476 Chapter 27--Fuels and Combustion No. 2 buckwheat anthracite, or rice size, is used only with forced draft equipment on mechanical stokers. No. 3 buckwheat anthracite, or barley, has no application in domestic heating. Firing Bituminous Coal 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. Air should be admitted over the fire through a special secondary air device, or through a slide in the fire door or by opening the fire door slightly. If the quantity of air admitted is too great the gases will be cooled below the ignition temperature and will fail to bum. The fireman can judge the quantity of air to admit by noting when the air supplied . is just sufficient to make the gases burn rapidly and smokelessly above the fuel bed. The red fuel in the firebox, before firing, excepting only a shallow layer of coke on the grate, should be pushed to one side or forward or back ward to form a hollow in which to throw the fresh fuel. Some manu facturers recommend that all red fuel be pushed to the rear of the firebox and that the fresh fuel be fired directly on the grate and allowed to ignite from the top. The object of this is to reduce the early rapid distillation ' of gases and to reduce the quantity of secondary air required for smoke less combustion. It is well to have the bright fuel in the firebox so placed that the gases from the freshly fired fuel, mixed with the air over the fuel bed, pass over the bed of bright fuel on the way to the flues. The bed of bright fuel then supplies the heat to raise the mixture of air and gas to the' ignition temperature, thereby causing the gaseous matter to burn and preventing the formation of smoke. The fuel bed should be carried as deep as the size of fuel and the available draft permit, in order to have as much coked fuel as possible for pushing to the rear of the firebox at the time of firing. A deep fuel bed allows the longest firing intervals. 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 stoking 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 requir ing stoking it may not be necessary to shake the grates, as the ash is usually dislodged during stoking. The output obtained from any heater with bituminous coal will usually exceed that obtainable with anthracite, since soft coal burns more rapidly than hard coal and with less draft. Soft coal, however, will require frequent attention to the fuel bed, because it burns unevenly, even though the fuel bed may be level, forming holes in the fire which admit too much air, chilling the gases over the fuel bed and reducing the available draft. . 477 ofAmerican Society Heating and Ventilating Engineers Guide, 1936 Semi-bituminous coal is fired as bituminous coal, and because of its caking characteristics it requires practically the same attention. 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, and to gently rocking the grates. It is recom mended that the slides in the firing door be kept closed, as the thinner fuel bed around the sides allows enough air to get through. Burning Coke - Coke is a very desirable fuel and usually will give satisfaction as soon as the user learns how to control the fire. Coke ignites and burns very, rapidly with less draft than anthracite coal. 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 more rapidly than an. anthracite fire 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. A deep fuel bed always should be maintained when burning coke. The grates should be shaken only slightly in mild weather and should be shaken only until the first red particles drop from the grates in cold weather. Since coke weighs only about half as much as anthracite per cubic foot only about half as much can be put in the firepot, so it will be- necessary to fire oftener. The best size of coke for general use, for small firepots where the fuel depth is not over 20 in., is that which passes over a 1 in. screen and through a \x/i in. screen. For large firepots where the fuel can be fired over 20 in. deep, coke which passes over a 1. in. screen and through a 3 in. screen can be used, but a coke of uniform size is always' more satisfactory. Large sizes of coke should be either mixed with .fine sizes or broken up before using. . Dustless Coal . - The practice of treating the more friable coals to allay the dust they create is increasing. The coal is sprayed with a solution of calcium chloride or a mixture of calcium and magnesium'chlorides. Both these salts are very hygroscopic and their moisture under normal atmospheric conditions keeps the surface of the coal damp, thus reducing the dust during delivery and in the cellar, and obviating the necessity of sprinkling the coal in the bin. . The coal is sometimes treated at the mine, but more usually-by the local distributor just before delivery. The solution is sprayed under high 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. Pulverized Coal Installations of pulverized coal burning plants in heating boilers are of the unit type, in which the pulverized coal is delivered into the furnace immediately after grinding, together with the proper amount of preheated 478 27Chapter --Fuels and Combustion air. With this apparatus, where the necessary furnace volume is ob tainable, high efficiencies can be obtained. . A 150-hp boiler has generally been considered the smallest size for which pulverized fuel is feasible. Complications are introduced if an installation with a single boiler has to take care of very light loads. . ' Hand Firing Hand firing is the oldest and the most widely used method of burning coal for heating purposes. To keep the fuel bed in proper condition where hand firing is used, the following general rules should be observed: 1. Remove ash from fuel bed by shaking the grates whenever fresh fuel is fired. This removes ash from the fire, enables the air to reach the fuel, and does away with the for mation of clinker which is melted ash. t 2. Supply the boiler with a deep bed of fuel. Nothing is gained by attempting to fire a small amount of fuel. A deep bed-of fuel secures the most economical results. 3. Remove ash from ashpit at least once daily. Never allow ash to accumulate up to the grates. If the ash prevents the air from passing through, the grate bars will burn out and much clinker trouble will be experienced. The principal requirements for a hand-fired,furnace are that it shall have enough grate at;ea and combustion space. The amount of grate area required is dependent upon the desired combustion 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 burn the gases of combustion completely than do the coals low in volatile matter. For burning high volatile coals provision should be made for mixing the combustible gases thoroughly so that com bustion 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. OIL Uniform oil specifications were prepared in 1929 by the American Oil Burner Association, in cooperation with the American Petroleum Institute, the U. S. Bureau of Standards, the American Society for Testing Materials and other interested organizations. Oil fuels were classified into six groups, as indicated by Table 3. When these specifications were prepared, it was generally accepted that the first three grades were adapted to domestic use, while the last three were suitable only for commercial and industrial burners." Today domestic installations may use No. 4 oil of the so-called heavy oil group, when and if said oil very closely follows the specifications of No. 3. Up-to-date listing by the Underwriter's Laboratories should be referred to before a No. 4 grade of fuel is used which merely meets Commercial Standards CS 12-35. Since the specifications as originally drawn provide for maximum limits only for the several grades, this differentiation has not proved stable. Realizing how unsatisfactory it is to have specifications which permit the substitution of one grade for another, the U. S. Bureau of Standards in cooperation with the American Society for Testing Materials is figuring 479 . American Society of Heating and Ventilating Engineers Guide, 1936 Table 3. Commercial Standard Fuel Oil Specifications11 A. Detailed Requirements for Domestic Fuel Oils Grade of Oil No. 1 Domestic Fuel Oil A light distillate . oil for- use in burners requir ing a high grade fuel. . No. 2 Domestic Fuel Oil . A medium distil late oil' for use in burners re quiring a high grade fuel. No. 3 Domestic . Fuel Oil ' A distillate fuel oil for use in burners where a low viscosity oil is required. Approx. Btu per Gal.* Flash Min. Point Max. Water and Sediment, Maximum Pour Point/ Maximum 139,000 110 F 165 F 0.05% or legal 15 F 141.000 125 F 190 F 0.05% or legal 15 F 143.400 150 F 200 F 0.1% or legal 15 F Distillation Test Viscosity Maximum 10% point, End point, maximum maximum 420 F 600 F 10% point, 90% point, maximum maximum 440 F 620 F 10% point, 90% point, Saybolt maximum maximum Universal at 100 F 460 F 675 F 55 seconds B. Detailed Requirements for Industrial Fuel Oils Grade of Oil Approx. Btu per ' Gal.6 Flash Point, Min. Max. No. 4. Industrial Fuel Oil An oil known to the trade as a light fuel oil for use in burners where a low vis cosity industrial fuel oil is required. No. 5 Industrial Fuel Oil Same as Federal Specifications Board specification for bunker oil " B '' for burners adapted to the use of indus trial fuel oil of medium viscosity. 144,500 146;000 150 F. See Note* 150 F .\ No. 6 Industrial Fuel Oil Same as Federal Specifications Board 150,000 specification for bunker oil "C" for burners adapted to oil of high viscosity. 150 F \ Water and Sediment, Maximum Pour Point/ Maximum 1.0% See Note* 1.0% Water sediment 1.75% 0.25% Viscosity, Maximum Saybolt Universal at 100 F 125 seconds Saybolt Furol at 122 F 100 seconds Saybolt Furol at 122 F 300 seconds "Adapted from "Fuel Oils," p. 2, U. S. Department of Commerce, Bureau of Standards, Commercial Standard CS1SS8, Washington, 1933. ^Government specifications do not give Bta per gallon, but they are noted here for information only. Lower or higher pour points may. be specified whenever required by conditions of storage and use. However, these specifications shall hot require a pour point less than 0 F under any conditions. ^Whenever required, as for example in burners with automatic ignition, a maximum flash point may be specified. However, these specifications shall not require a flash point less than 250 F under any conditions. - Pour point may be specified whenever required by conditions of storage and use. However, these specifications shall not require a pour point less than 15 F under any conditions. 480 Chapter 27--Fuels and Combustion on a new set of specifications providing for definite limits for each grade. When these specifications are adopted, it is expected that the National Board of Fire Underwriters will retest all burners using oils of the maximum specifications for the grade so that if a burner is approved for a certain grade it will burn any oil meeting the specifications for that'particular grade. . : Several burners adapted to industrial use have recently been listed for automatic operation with No. 5 oil. Usually oils No. 5 or 6 require preheating for proper operation, but where conditions are favorable, No. 5 can be used without the equipment that this entails. There are two reasons for the trend to lower grades, of oil. While the lighter oils contain slightly more heat units per pound, the weight per gallon increases more rapidly than the decrease in heat units per pound, and oil is bought by the gallon. As a consequence, while a No. 1 oil may contain 139,000 Btu per gallon, oil No. 5 may test 146,000 Btu per gallon, or 6 per cent more. Usually there is.a differential of 3 to 4 cents between the No. 1 and No. 5 oils, so that the economy of buying the heavier fuels is apparent; there remains the economic utilization of the heat content of the heavier oils. The cost of oil fuel is dependent also upon the amount that can be delivered at one time, and the method of delivery. Common practice has split the tank of the'truck delivering oils for domestic use info compart ments of 150 to 500-gal capacity, and these unit dumps are made the basis of price.. Where a truck can be connected to a storage-tank fill and quickly discharge its oil by pump, the price obviously can be less than where a smaller quantity must be drawn off in 5-gal cans and poured. For similar reasons an installation that can be supplied from a tank car on a siding provides for a lower unit fuel cost than one where the oil must be trucked, even in the large trucks holding 2,000 gal or more that are used for distributing the heavier oils. - . ' GAS Gas is broadly classified as being either natural or manufactured. Natural gas is a. mechanical mixture of several combustible and inert gases rather than a chemical compound. Manufactured gas as dis tributed is usually a combination of certain proportions of gases produced by two or more processes, and is often designated as city gas. When gas is burned a large amount of water vapor is produced as one of the products of combustion. This ordinarily escapes up the chimney, carrying away with it a certain amount of heat. However, when the heat value of gas is. determined in an ordinary calorimeter, this water vapor is.condensed and the latent heat of vaporization that is given up during the condensation is reported as a portion of the heat value of the gas. The heat value so determined is termed the gross or higher heat value and this is what is ordinarily meant when the heat value of gas is specified. The heat that is reclaimed by the condensation of the water vapor amounts to about 10 per cent of the total heat value. It is impractical to utilize the entire higher heat value of the gas in any house-heating appliance, because to do so it would be necessary to cool the products of 481 American Society of Heating and Ventilating Engineers Guide, 1936 combustion down below their dew point, which is ordinarily in the neighborhood of 130 F. . The actual dew point in the chimney is different from the theoretical value because excess air is admitted not only at the burner but also at the backdraft diverter which lowers the dew point. Natural gas is the richest of the gases and contains from 80 to 95 per cent methane, with small percentages of the other combustible hydrocarbons. In addition, it contains from 0.5 to 5.0 per cent of COit and from 1 to 12 or 14 per cent of nitrogen. The heat value varies from 700 to 1,500 Btu per cubic foot, the majority of natural gases averaging about 1,000 Btu per cubic foot. Table 4 shows typical values for the three main oil fields, although, values from any one field vary materially. Table 4 also gives the calorific values of the more common types of manufactured gas. Most states have legislation which controls the distri bution of gas and fixes a minimum limit to its heat content. The gross or higher calorific value usually ranges between 520 and 545 Btu per cubic foot, with an average of 535. A given heat value may be maintained and yet leave considerable latitude in the composition of the gas so that as distributed the composition is not necessarily the same in different dis tricts, nor at successive times in the same district. There are limits to the Table 4. Representative Properties of Gaseous Fuels, Based on Gas at 60 F and 30 in. Hg. Gab Btu per Cu Ft Low (Gras) (Net) Specific Am Riiquuuiv Gravot, fob Combus Am ss tion, 1.00 (Cu Ft) Products of Combustion Cubic Feet Total COt H> with Nt Ulti mate COt Dry Baffin Theoretical Flame Tem perature, (deq Fabr) Natural gas-- California 1200 1087 0.67 11.26 1.24 2.24 12.4 12.2 3610 Natural gas-- Mid-Conti nental 967 873 0.57 9.17 0.97 1.92 10.2 ll:7 3580 Natural gas.-- Ohio 1130 1025 0.65 10.70 1.17 2.16 11.8 12.1 3600 Natural gas-- Pennsylvania Retort coal gas Coke oven gas 1232 575 588 1120 0.71 510 0.42 521 0.42 11.70 5.00 5.19 U30 0.50 0.51 2.29 1.21 1.25 12.9 5.7 5.9 12.3 11.2 11.0 3620 3665 3660 Carburetted water gas 536 496 0.65 4.37 0.74 0.75 5.0 17.2 3815 Blue water gas 308 281 0.53 2.26 0.46 0.51 2.8 22.3 3800 Anthracite pro ducer gas 134 124 0.85 1.05 0.33 0.19 1.9 19.0 3000 Bituminous producer gas 150 140 0.86 1.24 0.35 0.19 2.0 19.0 3160 Oil gas 575 510. 0.35 4.91 0.47 1.21 5.6 10.7 3725 482 Chapter 27--Fuels and Combustion variation allowable, because the specific gravity .of the gas depends on its composition, and too great a change in the specific gravity necessitates a change in the adjustment of the burners of small appliances. Table 4 shows that a large proportion of the products of combustion when gas is burned may consist of water vapor, and that the greater the proportion of water vapor, the lower the maximum attainable CO% by gas analysis. The table also shows that a low calorific value does not neces sarily mean a low flame temperature since, for example, natural gas has a theoretical flame temperature of 3600 F and blue water gas of 3800 F, although it has a calorific value less than one third that of natural gas. The quantity of air given in Table 4 is that required for theoretical combustion, but with a properly designed and installed burner the excess .air can be kept low. The division of the air into primary and secondary is a rtiatter of burner design and the pressure of gas available, and also of the type of flame desired. PROBLEMS IN PRACTICE 1 Differentiate between the general characteristics of hard and soft coals. Hard coals contain fixed carbon in large proportions and in addition more ash is present especially in the smaller sizes. Soft coals have an increasing percentage of carbon in combination with hydrogen which is volatile and will distill on under high temperature, - producing smoke. ; 2 Name several important properties of coal from a utilization standpoint. a. Caking tendency, whether none, weak, or strong. b. Quantity of volatile matter. c. Friability. d. Fusibility of the ash. 3 What are the main data commonly available that fix the qualities of coal, and do these tell the whole story? a. Calorific value, Btu per pound. - b. Proximate analysis giving percentages of moisture, volatile matter, fixed carbon, ash, and sulphur. c. Temperature at which the ash softens. d. Screen sizes. Other important qualities not usually given are the friability of the coal, its caking tendency, and the qualities of the volatile matter. The percentage of ash and its fusion temperature do not tell how the ash is distributed or how much of it is less fusible lumps of slate or shale. 4 Are there available complete and sufficient data on gas and oils to fix their burning properties and furnace requirements? Yes. Because gas and oils are of simple and uniform composition, data are available to fix their burning properties and furnace requirements, but the ability to control their combustion is somewhat less determinable. 5 What effect does moisture in fuels have on their efficiency? With any solid fuel, latent and sensible heat are lost at the stack when moisture is dried out of the fuel in burning, and when its hydrogen is burned. Therefore, such fuels as sub-bituminous coal and lignite, which are high in moisture content, have a low efficiency. However, these efficiencies may be improved if the stack gases are cooled to room tem perature, by heating the feed water, for example. , 483 ---vr- andAmerican Society o/'Heating Ventilating Engineers Guide, 1936 6 What are the advantages of a sized fuel for heating furnaces? Because a sized fuel encourages a more uniform flow of air through the bed, the burning will be more uniform, and the bed will be less liable to develop holes and will require less attention. Uniformity of fuel size is more desirable as the area of the bed becomes smaller; it is less important with fuels that cake, but with sized fuels the caking will be more uniform and the air flow through the bed will be steadier. In addition, ash and pieces of slate are less likely to be segregated and to form lumps of clinker. 7 Does the size of a fuel affect the quantity of air required to burn it at a given rate? The total air required to give the same gas analysis at the stack is independent of the size of the fuel burned, but for non-caking fuels the ratio of the air passing through the fuel bed to the total air entering the burner base decreases, for the same thickness of bed, as the size of the fuel becomes smaller; this decrease is very rapid for sizes less than one inch. For coals that cake, this ratio will depend on the way the caked bed is broken up and on the size of the resulting- pieces. 8 Is the volatile matter which is given off when coals are burned of the same nature in all coals? _' No. The products given off by coals when they are heated differ materially in the ratios by weight of the gases to the oils and tars. No heavy oils or tars are given off by anthra cite, and very small quantities are given off by semi-anthracite. As the volatile matter in the coal increases to as much as 40 per cent of ash-free and moisture-free coal, in creasing amounts of oils and tars are given up. For coals of higher volatile content, thfe relative quantity of oils and tars decreases, so it is low in the sub-bituminous coals and in lignite. 9 Is smoke a primary product in the burning of fuels? - Visible smoke may include very small particles of carbon, oil, tar, water (condensed steam), and ash. Of these, the oils, tars, and ash are mainly primary products, and the water is partly primary. The carbon, which usually comprises the greater part of the smoke, results from the breaking up by heat of oils, tars, and such gases as methane, so it may be considered a secondary product. - 10 9' Is the sulphur in coals detrimental to combustion? Not so far as is known, but its complete combustion gives only 25 per cent as much heat as is given by the same weight of carbon. Sulphur is undesirable because it causes cor rosion of flues and stacks, and also because its gases pollute the atmosphere, and damage buildings and vegetation.11 11 How do deposits of soot on the surfaces of a boiler or heater affect the quantity of fuel burned? There are two effects. The soot 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 as great as has been believed and should not be over 6 per cent because the greater part of the heat is transmitted through the fire pot. The soot clogs the passages and reduces the draft; the loss of efficiency from this action may be much more, and also the lack of draft results in unsatisfactory heating. _ ., 484 Chapter 28 AUTOMATIC FUEL BURNING EQUIPMENT . .Residential Stokers, Apartment House Stokers, Commercial t Stokers, Domestic Oil Burners, Commercial Oil Burners, Gas Fired Appliances, Gas Boilers, Warm Air Furnaces, Space Heaters, Conversion Burners, Gas Appliances AUTOMATIC, mechanical equipment for the efficient combustion of coal, oil, and gas is considered, in this chapter. MECHANICAL STOKERS Coal can be burned more efficienctly on a mechanical stoker than by hand firing. The burning of coal involves uniformity of stoking, proper distribution over the fuel bed, admission of air as required to the fuel bed, and means for removing ash. The proper burning of the fuel on the grate is the function of the stoker and depends upon the stoker design. The burning of the volatile gases above the fuel bed is- a matter of furnace design. The requirements are the same regardless of the type of stoker. Proper care should be taken to provide furnaces sufficiently liberal in volume and with grates at a sufficient distance from the heating surface in order to permit proper combustion of gases. The standards that have been most universally adopted for the proportioning of furnaces are those of the Midwest Stoker Association. Stokers may be divided into four types according to their construction, namely, (1) overfeed flat grate, (2) overfeed inclined grate, (3) underfeed side cleaning type, and (4) underfeed rear cleaning type. They may also be classified according to their uses. The following classification has been recommended by the Stoker Manufacturers Association. Class I. Up to 60 lb coal feed per hour (Household). Class g. 60 to 500 lb coal feed per hour (Apartment house and small commercial); Class 3. 500 to 1200 lb coal feed per hour and less than 36 sq ft of grate area (General commercial heating and small high pressure steam plants). Class 4. Oyer 1200 lb coal feed per hour and over 36 sq ft grate area (Large com mercial and high pressure steam plants). . Overfeed Flat Grate Stokers : This type is represented bj; the various chain- or traveling-grate stokers. These stokers receive fuel at the front of the grate in a layer of uniform thickness and move it back horizontally to the rear of the furnace. Air is 485 American Society of Heating and Ventilating Engineers Guide, 1936 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 ashpit 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 burn the fuel without disturbing it. This type of stoker requires an arch over the front of the stoker to maintain ignition of the incoming fuel. Frequently, a rear combustion arch is required to main tain ignition until the fuel is fully consumed. A typical traveling-grate stoker is illustrated in Fig. .1. . . . ; . ... . Another and distinct type of overfeed flat-grate stoker is the spreaderor sprinkler type in which coal is distributed either mechanically or by air over the entire grate surface. This type of stoker has a wide application Chapter 28--Automatic Fuel Burning Equipment stoker is suitable for all coking coals while in the smaller sizes it is suitable for small sizes of anthracites. 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 gas is released, is mixed with air, and passes through the fire on small sized fuels and on certain special fuels such as lignites, high-ash coals, and coke breeze. Overfeed Inclined Grate Stokers ' '. \ In general the combustion principle is similar to the flat grate stoker, but this stoker (Fig. 2) is .provided with rocking grates set on an incline to advance the fuel during combustion. Alsb this type is provided with an ash .plate where ash is accumulated and from which it is dumped perodi- cally. This type of stoker is suitable for all types of coking fuels but preferably for those of low volatile content. Its grate action has the tendency to keep the fuel bed well broken up thereby, allowing for free passage of air. Because of its agitating effect on the fuel it is not so desirable for badly clinkering coals. Furthermore, it should usually be provided with a front arch to care for the volatile gas. ' Underfeed Side Cleaning Stokers In this type (Fig. 3), the fuel is fed in at tlie front of the furnace to one or more retorts, is advanced away from the retort sis combustion pro gresses, while finally the ash is disposed of at the sides. This type of 486 Fig. 2. Overfeed Inclined Grate Stoker Fig. 3. Underfeed Plunger Type Stoker where it is burned. The ash may be continuously discharged as in the small stoker or may be accumulated on a dump plate and periodically discharged. This stoker requires no arch as it automatically provides for the combustion of the volatile gas. Underfeed Rear Cleaning Stokers This type of stoker carries on combustion in much the same manner as the side cleaning type, but consists of several retorts placed side by side 487 American Society of Heating and Ventilating Engineers Guide, 1936 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. Class 1 Stokers, Household A common type of stoker in this class consists of a round retort having tuyeres at the top where all of the air for combustion is admitted. Coal is fed from a storage hopper (Fig. 4) outside of the boiler by means of a Fig. 4. Underfeed Screw Stoker, Hopper Type LENGTH Fig. 5. Underfeed Screw Stoker, Bin Type worm into the bottom of this retort and beneath the fire. The equipment includes a blower which is driven by the same motor that drives the stoker. Some household stokers are provided with automatic grate-shaking mechanism together with screw conveyers for removing the ash from the ashpit and depositing it in an ash receptacle outside the boiler. Certain types can also be provided with a cpal conveyer which takes coal from the storage bin and maintains a full hopper at the stoker. In some cases the stoker hopper functions as the coal bin as shown in Fig. 5, and an extended worm is used to convey the fuel to the boiler. They may feed coal to the furnace either intermittently or with a continuous flow regulated auto- 488 28--Chapter Automatic Fuel Burning Equipment matically to suit conditions. Where the boiler is provided with indirect coils for heating the domestic hot water, the stoker may be arranged so that it can be used the entire year to maintain a continuous hot water supply- .. Household stokers are made for all classes of fuel--anthracite, bitu minous and semi-bituminous. The United States Department of Com merce has issued commercial standards for household anthracite burners, which may be secured by application. The requirements stated in these standards are described in the following paragraphs. . Operating Requirements Efficiency. The over-all efficiency of the unit at all points above 50 per cent of maxi mum coal feed shall be above 50 per cent when installed in a round sectional cast iron boiler h.aving three intermediate sections and 154 in. of asbestos insulation or its equiva lent in good condition of repair, operating at 50 per cent or more of the boiler capacity. The efficiency shall be maintained for any continuous period of 4 hours during any test or observation run. . . Ash Loss. Combustible in ash shall not exceed 7.5 per cent of the Btu content of the. coal as fired at any rate of coal feed above 50 per cent of maximum. Methods of test . according to Code No. 3 of the A.S.H.V.E.1 are to followed in all details applicable to stoker testing. Clinker. Ash removing systems should at all times be capable of disposing of any clinker which may be formed under any conditions of operation with the coals prescribed. Combustion Rate. A combustion rate of at least 13 lb per square foot of horizontal projected area of ash ring per hour must be continuously maintained for at least 9 hours with the above conditions of efficiency, ash and clinker: Flue Gas. Flue gas shall be not below 6 per cent in carbon dioxide with a reasonably tight boiler at any rate of operation above 50 per cent of maximum coal feed. Maximum Rating. The maximum rating, in terms of gross square feet of water or ; steam radiation which the burner will supply, when intended for installation in the average existing cast-iron boiler, shall be 90 per cent of the maximum steam produced in a round cast-iron boiler in good repair having three intermediate sections and the equivalent of 1J4 in. of asbestos insulation. However, in no case shall the maximum rating.be greater than 29 sq ft of direct steam radiation for each pound of coal fired, per hour, and in no case shall ratings be based upon efficiency figures below 50 per cent. The maximum rating as defined in the preceding paragraph shall be based upon com bustion of Pennsylvania anthracite having the following approximate analysis: Volatile matter 3.5 to 9 per cent; ash content not to exceed 15 per cent; sulphur content under 1.5 per cent; ash fusing temperature 2750 F, or above (volatile, ash and sulphur content on dry basis in accordance with A.S.T.M. method D271-33); Btu content 12,000 or above; properly sized as follows: A No. 1 buckwheat should pass through a round mesh screen having in. holes and over a similar screen having in. holes. The uridersizing should not exceed 15 per cent and the oversizing should not exceed 10 per cent. A No. 2 buckwheat (rice) should pass through a round mesh screen having holes H6 in. in diameter and over a like screen having holes of in. in diameter. The under sizing should not exceed 15 per cent and the oversizing should not exceed 10 per cent. Coal Storage. It is recommended that the coal bin or closet be constructed so as to be dustproof. Electrical Consumption. The electrical consumption shall not exceed 18 kwh per 2000 lb of coal burned at any rate of coal feed above 50 per cent of the maximum. Operation Upon Other Sizes of Coal. - The foregoing specifications have been drafted for operating with the Nos. 1 and 2 buckwheat sizes of anthracite. In the.event that other sizes are recommended, ratings shall be based upon the same efficiency and ash . loss requirements. `A.S.H.V.E. Performance Test Code for Steam Heating Solid Fuel. Boilers (Code 3), (A.S.H.V.E. Transactions, Vol. 35, 1929). .. 489 American Society of Heating and Ventilating Engineers Guide, 1936 Banking. The burner shall be so constructed or controlled as to maintain a fire during an indefinite banking period. Acceleration. When the burner resumes operation after a 12 hour banking period, the time required for the stack temperature to reach a normal maximum shall not exceed 60 min. . ' Class 2 Stokers, Apartment House, Small Commercial . This class is used extensively for heating plants in apartments and hotels, and also for small industrial plants such as laundries, bakeries, and creameries. The majority of stokers used in this field are of the underfeed type. The principal exception is an overfeed type having step action grates in a horizontal plane and so arranged that they are alternately moving and stationary, and are designed to advance the fuel during com bustion to an ash plate at the rear.. All of the stokers are provided with a coal hopper outside of the boiler. In the underfeed types, the coal feed from this hopper to the furnace may be accomplished by a continuously revolving worm or by an intermittent plunger. The drive for the coal feed may be an electric motor, or a steam or hydraulic cylinder. With an electric motor, the connection between the driver and the coal feed may be thro.ugh a variable speed gear train which provides two or more speeds for the coal feed; or it may be through a simple gear train and a variable speed driver for the change in speed of the coal feed; or a simple gear train with a coal feed having an adjustment for varying the travel of the feeding device. With a steam or hydraulic cylinder, the power piston is connected directly to the coal feeding plunger. The stokers in this class vary also in their retort design according to the fuels and load conditions. The retort is placed approximately in the middle of the furnace and is provided with tuyere openings at the top on all sides. In the plunger-feed type the retort extends from the inside of the front wall entirely to the rear wall or to within a short distance of the rear wall. This type of retort has tuyeres on the sides and at the rear; These stokers also differ in the grate surface surrounding the retort. In many of the worm-feed stokers this grate is entirely a dead plate on which the fuel rests while combustion is completed. In the dead-plate type, all of the air for combustion is furnished by the tuyeres at the retort. . Because of this, combustion is well advanced over the retort so that it may easily be completed by the air which percolates through the fuel bed. With the dead-plate type of grate the ash is removed through the fire doors and it is therefore desirable that the fuel used shall be one in which the ash is readily reduced to a clinker at the furnace temperature, in order that it may be removed with the least disturbance of the fuel bed. In other stokers in this class, the grates outside of the retort are airadmitting and some stokers have shaking grates. These grates permit a large part of the ash to be shaken into the ash pit beneath, while the clinkers are removed through the fire doors. With this type of grate, the main air chamber extends only under the retort while the side grates receive air by natural draft from the ash pit. In still other stokers of this class, the main air chamber extends beyond the retort and is covered with fuel-bearing, air-supplying grates. With this type of grate, the fuel is supplied with air from the main air chamber 490 WS 28Chapter --Automatic Fuel Burning Equipment . throughout combustion. Also with this type of grate, dump plates are . provided beyond the grates where the ash accumulates and from which it can be dropped periodically into the ash pit beneath. Stokers in this class are compactly built in order that they may fit into standard heating boilers and still leave room for sufficient combustion space above the grates. The height of the grate is approximately the same as that of the ordinary grates of boilers, so that it is usually possible to install such stokers with but minor changes in the existing equipment. In some districts, there are statutory regulations governing such settings. These stokers vary in furnace dimensions from 30 in. square to approxi mately 66 in. square. The capacity of the stokers is measured by the amount of coal that can be burned, per hour. In general, manufacturers recommend that, for continuous operation, the coal burning rate shall not exceed'25 lb of coal per square foot of grate per hour, while for short ' peaks this rate may be increased to 30 lb per hour. Although these stokers were designed to burn bituminous coal, types are available for the semi-bituminous coals such as Pocahontas and New River. They can also be- used to burn the small sizes of anthracite but at a somewhat lower rate. It is often customary to have the janitor or some other attendant care for the boiler as one of his duties: Under these conditions the heating plant does not receive the same careful attention as it would if a man devoted his entire attention to the fire. With periodic hand-firing, the boiler is operated inefficiently much of the time. With a stoker, the boiler is operated at the rate that the conditions require so long as there is coal in the hopper. With hand firing, it is customary to use a more expensive size of fuel, while with a stoker the smaller sizes are used at a considerable saving in the cost per ton. Because the stoker responds promptly to automatic regulation, it is possible to maintain a reasonably constant standard. Also because the stoker feeds the fuel regularly and in small quantities without losses due to opening doors, it is more efficient than hand firing. This increase irt efficiency depends entirely on con ditions, with a minimum of about 10 per cent and a maximum of about 25 per cent. Another type of stoker which may be used in connection with smajl size coal is a pneumatic type as shoWn in Fig. 6. The equipment may be arranged with a pipe conveying the fuel from a storage space directly to the burner nozzle with Secondary air supplied from a separate unit located near the boiler. . .. 491 American Society of Heating and Ventilating Engineers Guide, 1936 Qass 3 Stokers, General Commercial, Small High Pressure Plants The general commercial heating and high pressure plant with boilers burning from 500 lbs of coal per hour to 1200 lbs of coal per hour, is a field distinct from the large commercial and industrial field. The pre valent type of stoker employed is the single retort underfeed side-cleaning type. In this field is found the greatest financial return on stoker invest ments due to the fact that 90 per cent of the fuel is purchased in the retail market where prices are on the average 40 per cent higher for the same fuel than if the coal were purchased in carload quantities. This is, therefore, an extremely important class of stokers. Savings of 40 per cent to 50 per cent are not at all unusual, and many plants show as much as a 50 per cent return on the investment. Automatic Stoker Controls The industry developed by stokers in Classes 1, 2 and 3 has been due as much to the application of proper controls as to the stoker itself, as the types of stokers used in these classes are not basically new, while the industry is distinctly new, originating in 1923. The usual controls applied are as follows: a. Thermostats (plain and clock). b. Limit Controls (steam, vapor, hot water, etc.). c. Stack Temperature or Time Controls (for actuating fires periodically). d. Relay (for low voltage controls). e. Safety or Overload Cutout (for protection against overload). . . Class 4 Stokers, Large Commercial, High Pressure Steam Plants This class includes stokers with grate areas, above 36 sq ft and with hourly burning rates of over 1200 lbs of coal per hour. The prevalent stokers in this field are: . a. Overfeed flat grate stokers. b. Overfeed inclined grate stokers. c. Underfeed side cleaning stokers. d. Underfeed rear cleaning stokers.. ' ' , Overfeed inclined grate stokers are seldom built in sizes of over 500 hp and are not as extensively used as other types of stokers. Underfeed side-cleaning stokers are made in sizes up to approximately 500 hp and in this field are extensively'used. These stokers are not so varied in design as those in the smaller classes although the principle is much the same. Practically all of them are of the front coal feed type, either power driven or steam driven. ' Dump plates at the side are manually operated. These stokers are heavily built and designed to operate continuously at high boiler ratings with, a minimum amount of attention. Because of the fact that all volatile gas must pass through the fire before reaching the combustion chamber, these stokers will operate smokelessly under ordinary conditions. Also because of the fact that these stokers are always provided with forced draft, they are the most desirable type for fluctuating loads or high boiler ratings. . In the design of the grates for supporting the fuel between the retort and the ash plates, the stokers differ in providing for movement of the 492 Chapter 28--Automatic Fuel Burning Equipment fuel during combustion. Sorne stokers are designed with fixed grates of sufficient angle to provide for this movement as the bed is agitated by the incoming fuel, while others have alternate moving and stationary bars in this area and provide for this movement mechanically. In either type, with proper operation, all refuse will be deposited at the dump plate. Recent developments in this type of stoker provide for sliding distributor blocks along the bottom of the retorts which give flexibility in providing proper distribution of fuel over the grate area and assist in preventing coke masses when strong coking coals are used. Another difference in these stokers is that some use a single air chamber under the whole grate area thus having the same air pressure under the ignition area as under the rest of the grate, while others have a divided air chamber using the full air pressure under the ignition area and a reduced air pressure under ,:thfe remainder of the grate. These stokers vary in size from approxi- . mately 5 sq ft to a maximum of 8% sq ft. . The most prevalent type of rear-cleaning underfeed stoker is the multiple retort design. Occasionally double or triple retort side-cleaning, underfeeds are made. The multiple retort underfeed stoker is made for the largest sizes of boilers for large industrial plants and central stations. This stoker has reached a very fine stage of. development mechanically and in the matter of air supply and control. In some instances zoned aircontrol has been applied both longitudinally and transversely to the grate surface. Ash dumps on smaller sizes are sometimes manually operated, Table 1. Recommended Setting Heights for Heating Boilers Equipped with Mechanical Stokers3 Firebox Boilers Actual Load 2500 5000 7500 10000 12500 15000 20000- 25000 A 18" 18" 20" 20" 22" ' 22" .24" 24" B 42" 48" 54" 60" 66" 72" 78" . ' 84" 30000 ` 24" ?4" 4 = Distance from bottom of Water Leg to floor. B = Distance from Crown Sheet to bottom of Water Leg. Compact Welded Boilers Actual Load 2500 5000 7500 10000. 12500. 15000 20000 25000 30000 A 18" 18" 20" 20" 22" 22" 24" 24" 24" B 30" 33" 36" 42" 45" 48" 54" 60" 60" A = Distance from bottom of Water Leg to floor. . , B - Distance from Crown Sheet to bottom of Water.Leg H. R. T. Boilers . Hp . 50 75 100 125 150 175 200 225 250 275 300 A 5'-0" 5'-6" 6'-0" 6'-6" 7'-0"' 7'-0" 7'-6"s q-0" 8'-6" S>'-0" 9'-0" A = Distance from bottom of shell to floor. . ` Up - Installed horsepower. fn the case of the Firebox or Compact Welded type boilers the desired setting height can be obtained by combining A and B dimensions. The load ratings shown for this class of boilers are actual developed loads .in square feet of equivalent cast iron steam radiation and are not manufacturers rating. . The setting heights given for H. R. T. boilers may be used for developed loads up to 50 per cent above normal rating. From Data Prepared by the Midwest Stoker Association. 493 American Society of Heating and Ventilating Engineers Guide, 1936 while larger sizes are power operated. The number of retorts and dimen sions of furnaces are practically unlimited. The V-type stoker is practically obsolete although many are still in operation. In this stoker, the grates are inclined downward from both sides of the furnace to a low point at the middle where there is either a dump plate for periodic disposal of the ash or a rotary ash grate for con tinuous discharge of ash. In this stoker, the fuel is fed into a hopper at the top of the grate on each side of the furnace and advanced down the grates to the center where the refuse is accumulated. This stoker is always provided with a combustion arch over the entire furnace for the purpose of assuring thorough combustion of the solid fuel and providing a furnace temperature sufficiently high to burn the volatile gases. Because of this high furnace temperature and because so little of the boiler surface is exposed to the fire to assist in carrying off the heat by radiation, this stoker is characterized by severe clinkering in the ash area. With all types of overfeed stokers, the most desirable installations are in boilers which are operated with comparatively uniform loads and moderate rates of combustion, since, even with good combustion arches, fluctuating loads or high combustion rates result in smoke. Table 1 gives recommended setting heights for heating boilers equipped with mechanical stokers. , DOMESTIC OIL BURNERS An oil burner is a mechanical device for producing heat automatically and safely from liquid fuels. This heat is produced in the furnace or firepot of hot water or steam boilers or warm air furnaces and is absorbed by the boiler, and thus made available for distribution to the house through the heating system. Heat production is thus only one of many functions to be performed by a heating system. Efficient heat production with any kind of fuel requires that all com bustible matter in the fuel shall be completely consumed and that it shall be done with no more excess air than necessary. The combustion of oil is a rather rapid chemical reaction. Excess air provides an over supply of oxygen so that all of the oil, composed of carbon and hydrogen, will be completely oxidized and thus produce all the heat possible. The use of unnecessary excess air means no increase or decrease in the heat produced but it does mean that some air is needlessly heated and thrown away. This loss cannot be counteracted by any other part of the heating system and -is therefore chargeable to the fuel-burning device. Oil is a highly concentrated fuel composed exclusively of hydrogen and carbon. In its liquid form oil cannot burn. It must be converted into a gas or vapor by some means. If the excess air is to be kept within efficient limits it means that air must be supplied in carefully regulated quantities. The air and oil vapor must be vigorously mixed to get a rapid and complete chemical reaction. The better the mixing, the less excess air that will be needed. The combustion must take place in a space that maintains the temperatures high so the reaction will not be stopped before completion. When equipped with a means of igniting the oil and safety devices to guard against mishaps, the oil burner possesses all of the elements to be efficient and automatic. 494 Chapter 28--Automatic Fuel Burning Equipment - The number of combinations of the characteristic elements of domestic oil burners is rather large and accounts for the variety of burners found in actual practice. Domestic oil burners may be classified as follows: : 1. AIR SUPPLY FOR COMBUSTION . . a. Atmospheric--by natural chimney draft. b. Mechanical--electric-motor-driven fan or blower. c. Combination of (a) and (6)--primary air supply by fan or blower and secondary air supply by natural chimney draft. 2. METHOD OF OIL PREPARATION . a. Vaporising--oil distills on hot surface or in hot cracking chamber. b. A tomizing--oil broken up into minute globules. (1) Centrifugal--by means of rotating cup or disc. - (2) Pressure--by means of forcing oil under pressure through a small nozzle or orifice. (3) Air or steam--by high velocity air or steam jet in a special type of . . nozzle. .' (4) Combination air and pressure--by air entrained with oil under pressure . and forced through a nozzle. c. Combination of (a) and (6). ' 3. TYPE OF FLAME a. Luminous--a relatively bright flame. An orange-colored flame is usually best if no smoke is present. . :- b. Non-luminous--Bunsen-type flame (*.., blue flame). 4. METHODS OF IGNITION a. Electric. .' (1) Spark--by transformer producing high-voltage sparks. Usually shielded to avoid radio interference. May take place continuously while the burner is operating or just at the beginning of operation. (2) Resistance--by means of hot wires or plates. r b. Gas. (1) Continuous--pilot light of constant size. (2) Expanding--size of pilot light expanded temporarily at the beginning of burner operation. ' ' c. Combination--electric sparks light the gas and the gas flame ignites the oil. d.. Manual--by manually-operated gas torch for continuously operating burners. 5. MANNER OF OPERATION a. On and off--burner operates only a portion of the time (intermittent). b. High and low--burner operates continuously but varies from a high to a low flame. c. Graduated--burner operates continuously but flame is graduated according to needs by regulating both air and oil supply. A trade classification of oil burners consists of the following general types: (a) gun, (>) rotary and (e) pot. The gun type is characterized by an air tube, usually horizontal, with oil supply pipe centrally located in the tube and so arranged that a spray, of atomized oil is introduced and mixctfin the firepot with the air stream emerging from the air tube. A vanety of patentee! shapes are employed at the end of the air tube to influence the direction and speed of the air 495 . of andAmerican Society Heating Ventilating Engineers Guide, 1936 and thus the effectiveness of the mixing process. The most distinguishing feature of the rotary type is that the oil is discharged to the furnace or fire-pot by a rotating element of special design. The pot type can be identified by the presence of a metal structure, called a pot, in which combustion takes place. While fire brick linings in the boiler are necessary with the gun and rotary type, they are not needed with the pot type. The oil burners are operated by a small electric motor which pumps the oil and some or all of the air required. The smallest sizes can generally burn not much less than gal of oil per hour. The grade of oil burned ranges from No. 1 to No. 4 (see pg. 479 to 481). No. 4 oil is the heaviest and most viscous of the various grades mentioned. An oil burner satis factory for No. 4 oil can burn any of the lighter grades easily but an oil burner recommended for No. 2 oil should never be supplied with- the heavier grades. It has been found that while the heavier grades of oil have a smaller heat value per pound, they have, due to greater density, a larger heat value per gallon. The relative economy of the various grades must be based upon price and the amount of excess air required for clean and efficient combustion. ' The Combustion Process .. Efficient combustion as previously indicated must produce a clean flame and must use relatively small excess of air {i.e.,- between 25 and 50 per cent). This can be done only by vaporizing the oil quickly.^com pletely, arid mixing it vigorously with air in a firepot hot enough to sup port the combustion. A vaporizing burner (i.e., pot type) prepares the oil vapor before it mixes with air to any extent. If air and oil vapor temperatures are high and the firepot hot, a clear blue flame is produced. There may. be a deficiency of air as shown by the presence of carbon . morioxide (CO) or an excessive supply of air, depending upon burner adjustment, without altering the clean, blue appearance of the flame. An atomizing burner {i.e., gun and rotary types) is so named because the oil in one way or another is mechanically separated into very fine particles so the surface exposure of the liquid to the radiant heat of the firepot is vastly increased'and vaporization proceeds quickly. Since the air enters the firepot with the liquid fuel particles, it follows that mixing, vaporiza tion and burning are all occurring at once in the same space. This pro duces a luminous instead of a blue or non-luminous flame. In this case a deficient amount of air is indicated by a dull red or dark orange flame with smoky flame tips. ' An excessive supply of air may produce a brilliant white flame in some cases or, in others, a short ragged flame with incandescent sparks flashing through the combustion space. While extreme cases may be easily detected, it is generally not possible to distinguish, by the eye alone, the finer adjustments which competent installation requires. Certain tests indicate that there is no difference in economy between a blue flame and a luminous flame if the position, shape and the per cent of excess air of both flames are about the same. Furnace or Firepot Design : It is evident that the atomizing burner is dependent upon the sur rounding heated refractory or firebrick surfaces to vaporize the oil and 496 28--Chapter Automatic Fuel Burning Equipment support combustion. While the importance of the firepot is obvious, its design has been troublesome. Unsatisfactory combustion may be due to inadequate atomization and mixing. A firepot can only compensate for these things to a limited extent. If liquid fuel continually reaches some part of the firebrick surface, a carbon deposit will result. Fundamentally, the firepot 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 firepot 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 firepot thus 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 quite hot. This insures quick vaporization, rapid combustion and better mixing by eliminating dead or inactive spaces in the firepot. An overhanging arch . at the back of the firepot 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 atorni- zation- and vigorous mixing are achieved by the burner, firepot design becomes a less critical matter. Where secondary air is used, firepot design is quite important. Manufacturers generally provide careful directions and in some instances provide special firebrick shapes suited to their burners. Oil and Air Adjustments Where adjustments of oil and air have been made which give efficient combustion, the problem of maintaining the adjustments constant be comes an important one. Particularly is this true when the change causes the per cent of excess air to decrease below allowable limits of the burner. A decrease in air supply while the oil delivery remains constant or an increase in oil delivery while .the air supply remains constant will, make the mixture of oil and air too rich for clean combustion. The more efficient the adjustment {i.e., 25 per cent excess air) the more critical it will be of variations. The oil and air supply rates must remain constant! The following factors may influence the oil delivery rate: (o) changes in oil viscosity due to temperature change or. variations in grade of oil delivered, (b) erosion of atomizing nozzle, (c) fluctuations'in by-pass relief pressures and (d) possible variations iri methods 2b (3) and 2b (4) listed in the previous classification table. Note that any change due to partial stoppage of oil delivery wijl increase the proportion of excess air. This will result in less heat, reduced economy and possibly a complete inter ruption of service but usually no soot will form. . The following factors may influence the air supply: (a) changes in firepot draft due to a variety of causes {i.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 pur poses, possible stoppage of the chimney and changes in draft resistance of boiler due to partial stoppage of. the flues), {b) changes in air inlet adjust ments to the fan--collection of lint and dirt on the inlet grille may be enough in some case's. 497 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Measurement of the Efficiency of Combustion . Efficient combustion being based upon a clean flame and certain proportions of oil and air employed, it is possible to determine the results by analyzing the gases formed by the combustion process. An Orsat apparatus is a device which measures the volume of carbon dioxide (COt), oxygen (02) and carbon monoxide (CO) in the fluegases. Except in the case of a non-luminous flame it is usually sufficient to analyze only for carbon dioxide (CO2). A showing of 10 to 12 per cent indicates the best adjustment if the flame is clean. Most of the good installations at the present time show from 8 to 10 per cent COt- Taking into account the potential hazard of oil or air fluctuations with low excess air (high COt) a setting to give 10 per cent COt constitutes a reasonable standard for the majority of oil burners. '. Additional Design Considerations - Efficient combustion is found to be a question of good design plus a competent installation but it is not the sole feature of a completely satis factory job. The following items should all be considered: (a) clean and efficient combustion, (b) a setting of the oil-burning rate to give the proper gross load, (c) a boiler to absorb the heat efficiently, (d.) quiet operation, and (e) suitable control and safety devices. The Gross Load See Chapter 25 for general material on allowances, etc. To the design or heat loss of the house (Chapter 7), it is customary to add an allowance for piping and pick-up. The most common value for piping is 25 per'cent and for pick-up 20 per cent. To these allowances should be added an allowance where domestic hot water is heated by the boiler. (See Chapter 35 for information on Domestic Hot Water). The design load plus the allowances indicates the gross load that should be produced by the boiler. While in every case the gross load will exceed the design load if adequate heating response is to be achieved, there is, however, no object whatever in over-estimating the allowances. The only effect would be to reduce the time of pick-up by a few minutes. Otherwise, it might mean forcing thie boiler unduly and increasing the cost of operation. ` . ' Setting the Rate of Oil Burning * The rate of oil burning to get the gross output depends upon the com bustion (i.'e., per cent COt) and the efficiency of the boiler in absorbing heat. The oil burning rate in conversion jobs--where a burner is placed in existing equipment--is troublesome to adjust accurately because the boiler efficiency is usually a matter of conjecture rather than actual knowledge. In general, each gallon of oil burned per hour will'produce'a , boiler output of from 300 to 450 ft of steam radiation (see Fig. 7). The number of possible burners, adjustments, and boilers makes each instal lation a separate problem. Obviously, a satisfactory setting depends upon the knowledge, experience and judgment of the individual installer. It seems wise to set the oil-burning rate oh the low rather than high side. The tendency has always been the other way. The oil-burning rate can easily be increased. If properly explained to the owner, he will appreciate the situation if subsequent adjustments are necessary. 498 Chapter 28--Automatic Fuel Burning Equipment Boiler-Burner Units . 'Boilers especially designed for oil burners are gradually becoming available to the purchaser of this type of equipment. They are used for replacements as well as for new installations. These boilers have more heating surface than the older coal-burning designs. Flue proportions and gas travel have been changed with beneficial results. All questions of firepot design, capacities, efficiencies, etc., have been determined. The selection of the proper size of unit should be a simple process. Controls , , . Oil burner controls may be divided into two parts: (o) devices to regulate burner operation, so the desired house heating result may be ' 'obtained and. (b). devices for the safety and protection of the boiler and Fig. 7. Full Load Rate op Oil Consumption for Heating Boilers burner. For control devices generally consult Chapter 14. The room thermostat has recently been improved to provide more frequent burner operation and greater uniformity of room temperature. Class (b) controls comprises a device to shut off the burner if the oil fails to ignite or if the flame should cease due to lack of oil; a device actuated by steam boiler pressure to shut off the burner when the pressure reaches some pre determined value; a device on the boiler to shut off the burner if the water level acts too low for safety or one which automatically feeds additional water to the boiler; a device on warm air furnaces to shut off the burner if the air temperature gets too high; a valve in the oil supply line which automatically closes in the event of fire iri or near the cellar; and a device to keep the temperature of the boiler water within certain limits when it is being used to heat domestic hot water. These devices are all tested, and approved by the Underwriters' Laboratory of Chicago, 111., before they are offered to the purchaser. The selection of class (b) devices is made by the oil burner manufacturer. ' '1 499 '/ American Society of Heating and Ventilating Engineers Guide, 1936 Domestic Hot Water Supply Provisions for heating domestic hot water in connection with automatic fuel-burning devices through heat exchangers attached to the boiler are fully described in Chapter 35. COMMERCIAL OIL BURNERS Liquid fuels are used for heating apartment buildings, hotels, public and office buildings, schools, churches, hospitals, department stores, as well as industrial plants of all kinds. Contrary to domestic heating, con venience seldom is a dominating factor, the actual net cost of heat pro duction usually controlling the selection of fuel. Some of the largest office buildings have been using oil for many years. Many department stores have found that floor space in basements and sub-basements can be used to better advantage for merchandising wares, and credit the heat pro ducing department with this saving. Wherever possible, the boiler plant should be so arranged that either , oil or solid fuel can be used at will, permitting the management to take advantage of changes in fuel costs if any occur. Each case should be considered solely in the light of local conditions and prices. Burners for commercial heating may be either large models of types used in domestic heating, or special types developed to meet the condi tions imposed by the boilers involved. Generally speaking, such burners are of the mechanical or pressure atomizing types, the former using rotating cups producing a horizontal torch-like flame. As much as 350 gal of oil per hour can be burned in these units, and frequently they are arranged in multiple on the boiler face, from two to five burners to each boiler. The larger installations are nearly always started with a hand torch, and are manually controlled, but the use of automatic control is increasing, and completely automatic burners are now available to burn the two heaviest grades of oil. Nearly all of the smaller installations, in schools, churches, apartment houses and the like, are fully automatic. Because of the viscosity of the heavier oils, it is customary to heat them before transferring by truck tank. It also has been common practice to preheat the oil between the storage tank and the burner, as an aid to movement of the oil as well as to atomization. This heating is accomplished by heat-transfer coils, using water or steam from the heating boiler, and heating the oil to within 30 deg of its flash point. ; Unlike the domestic burner, units for large commercial applications frequently consist of atomizing nozzles or cups mounted on the boiler front with the necessary air regulators, the pumps for handling the oil and the blowers for air supply being mounted in sets adjacent to the boilers. In such cases, one pump set can serve several burner units, and common prudence dictates'the installation of spare or reserve pump sets. Pre-heaters and other essential auxiliary equipment also should be in stalled in duplicate, ; Boiler Settings .... As the volume of space available for combustion is the determining factor in oil consumption, it is general practice to remove grates and 500 Chapter 28--Automatic Fuel Burning Equipment extend the combustion chamber downward to include or even exceed the ash-pit volume; in new installations the boiler should 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 lb of oil can properly be burned. This cor responds to a maximum liberation of about 38,000 Btu per cubic foot per hour. There are indications that at times much higher fuel rates may be satisfactory. This in turn suggests that the value of 38,000 Btu per cubic foot per hour might be adjusted according to good engineering judgment. For best results, care should be taken to keep the gas velocity below 40 ft per second. Where checkerwork of brick is used to provide secondary air, good practice calls for about 1 sq in. of opening for each pound of oil fired, per hour.: Such checkerwork is.best adapted; to flat flames; or to ^mcaI;flamesEtiratcan;:bespread;over.thefloorofithecombustion:ehamben..... .Thepropecbrickingofalargeorrevenmediumsizedboilerforoilfiringis 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 metallic or fire-brick 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. GAS-FIRED APPLIANCES The increased use of gas for house heating purposes has resulted in the production of such a large number of different types of gas-heating systems and appliances that today there is probably a'greater variety of them than there is for any other kind of fuel. Gas-fired heating systems may be classified as follows: I. Gas-Designed Heating Systems. A. Central Heating Plants. 1. Steam, hot water, and vapor boilers. 2. Warm air furnaces. . B. Unit Heating Systems. 1. Warm air floor furnaces. 2. Industrial unit heaters. 3. Space heaters. 4. Garage heaters. II. Conversion Heating Systems. A. Central Heating Plants. 1. Steam, hot water and vapor boilers. ' ` 2. Warm air basement furnaces. ' .. . The majority of these systems are supplied with either automatic or manual control. Central heating plants, for example, whether gas. designed or conversion systems, may be equipped with room temperature control, push button control, or manual control. Although no exact rules can be prescribed as to the field best covered by each of the foregoing systems, each installation will have problems point ing more or less directly to some particular type of heating equipment. 501 American Society 0/Heating and Ventilating Engineers Guide, 1936 Gas-Fired Boilers ' Information on gas-fired boilers will be found in Chapter 25. Either snap action or throttling control is available for. gas boiler opera tion.; This is especially advantageous in straight steam systems because steam pressures can be maintained at desired points, while at the same time complete cut-off of gas is possible when the. thermostat calls for it. Warm Air Furnaces . .. . There are two general classes of gas-fired warm air furnaces, the gravity furnace which depends upon the natural tendency.of heated air to rise, providing the proper circulation of heated air into the room, and the mechanical circulation furnace by which the .air to be heated is forced through or drawn through the furnace by means of a fan. Warm air furnaces are variously constructed of cast iron, sheet metal and combinations of the two materials. If sheet metal is used, it must be of such a character that it will have the maximum resistance to the cor rosive effect of the products of combustion. 'With some varieties of manufactured gases, this effect is quite pronounced." Warhi air furnaces are obtainable in sizes from those sufficient to heat- the largest residence down to sizes applicable to a single room. The practice of installing a number of separate furnaces to heat individual rooms is peculiar to mild climates, such as that of Southern California. Small furnaces, frequently controlled by electrical valves actuated by push-buttons in the room above, are often installed to heat rooms where heat may be desired for an hour or so.each day. These furnaces are used also for heating groups of .rooms in larger residences. In a system of this type-each furnace should supply a group of rooms in which the heating requirements for each room in the group are similar as far as the period of heating and temperature to be maintained are concerned. Bedrooms, living rooms, and dining rooms often present excellent possibilities for this type of furnace! The same fundamental principle of design, that is followed in the con struction of boilers, that is, breaking the hot gas up into fine streams so that all particles are brought as close as possible to the heating surface, is equally applicable to the design of warm air furnaces. The desirability of using an appliance designed for gas, when, gas is to be the fuel, applies even more strongly to furnaces than to boilers. Codes for proportioning warm air hpating plants, such as that formu lated by the Notional Warm Air Heating and Air Conditioning Association (see note p. 429), are equally applicable to gas furnaces and coal furnaces. Recirculation should always be practiced with gas-fired warm air furnaces. It not only aids in heating, but is essential to economy. Where fans are used in connection with warm air furnaces for residence heating, it is well to have the control of the fan and of the gas so coordinated that there will be sufficient delay between the turning on of the gas and the starting of the fan to prevent blasts of cold air being blown into the heated rooms. An additional thermostat in the dir duct easily may be arranged to accomplish this. . Floor Furnaces - ., Warm air floor furnaces are well adapted for heating first floors, or 502 - Chapter 28--Automatic Fuel Burning Equipment 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 as any number of rooms may be heated without heating the others. With the usual type the register is installed in the floor, the heating element and gas piping being suspended below. Air is taken downward between the two sheets of the double casing and discharged upward over the heating surfaces and into the room. The appliance is controlled from the room to be heated by means of a control lever located near the edge of the register. The handle of the control is removable as a precaution against accidental turning on or off of the gas to the furnace. Space heaters are generally used for auxiliary heating, but may be, and . are in many cases, installed for furnishing heat to entire buildings. Space ' ..heaters are quite extensively used for house heating in milder climates - such as exist in the South and Southwest. With the exception of wall heaters, they are portable, and can be easily removed and stored during the summer season. Although they should be connected with solid piping it is sometimes desirable to connect them with flexible gas tubing in which case a gas shut-off on the heater is not permitted, and only A.G.A. " approved tubing should be used. ' Space Heaters- 1 ' Parlor furnaces or circulators are usually constructed to resemble a cabinet radio. They heat the room entirely by convection, t.e., the cold air of the room is drawn in near the base and passes up inside the jacket around a drum or heating section, and out of the heater at or near the top. These heaters cause a continuous circulation of the air in the room during the time they are in operation. The burner or burners are located in the . base at the bottom of an enclosed combustion chamber. The products of combustion pass up around baffles within the heating element or drum, and out the flue at the back near the top. They are well adapted not only for residence room heating but also for stores and offices. Radiant heaters make admirable auxiliary heating appliances.to be used during the occasional cool days at the beginning and end of the heating season when heat is desired in some particular room for an hour or two. The radiant heater gives off a considerable portion of its heat in the form of radiant energy emitted by an incandescent refractory that is heated by a Bunsen flame. They are made in numerous shapes and designs and in sizes ranging from two to fourteen or more radiants. Some have sheetiron bodies finished in enamel or brass while others have cast-iron or brass frames with heavy fire clay bodies. An atmospheric burner is supported near the center of the base, usually by set screws at each end. Others have a group of small atmospheric burners supported on a manifold attached to the base. Most radiant heaters are supported on legs and are portable; however, there are also types which are encased in a jacket .which fits into the wall with a grilled front, similar to the ordinary wall register. Others are encased in frames which fit into fireplaces. ' Gas-fired steam and hot water radiators are popular types of room heating appliances. They provide a form of heating apparatus for intermittently heated spaces such as stores, small churches and some types of offices and apartments.. They are made in a large variety of shapes and sizes and are 503 American Society of Heating and Ventilating Engineers Guide, 1936 similar in appearance to the ordinary steam or hot water radiator con nected to a basement boiler. A separate combustion chamber is provided in the base of each radiator and is usually fitted with a one-piece burner. They may be secured in either the vented or unvented types, and with steam pressure, thermostatic or room temperature controls. : Warm air radiators are similar in appearance to the steam or hot water radiators. They are usually constructed of pressed steel or sheet metal hollow sections. The hot products of combustion circulate through the sections and are discharged out a flue or into the room, depending upon whether the radiator is of the vented or unvented type. ' Garage heaters are usually similar in construction to the cabinet circulator space heaters, except that safety screens are provided over all openings into the combustion chamber to prevent any possibility of explosion from gasoline fumes or other gases which might be ignited by an open flame. They are usually provided with automatic room tem perature controls and are well suited for heating either residence or commercial garages. Conversion Burners Residence heating with gas through the use of conversion burners in stalled in coal-designed boilers and furnaces represents a common type of gas-fired house heating system, especially in natural gas territories. In many conversion burners radiants or refractories are employed to convert some of the energy in the gas to radiant heat. Others are of the blast type with luminous flames, operating without refractories. In each case an attempt is made to transfer the majority of the heat from the gas to the medium to be heated within the fire pot itself because of the low heat transfer that takes place in the flue passages. ^ Many conversion units are equipped with sheet metal secondary air ducts which are inserted through the ash-pit door. The duct is equipped with automatic air controls which open when the burners are operating and close when the gas supply is turned off. This prevents a large part of the circulation of cold air through the combustion space of the ap pliance vjjien not in operation. By means of this duct the ait necessary for proper combustion is supplied directly to the burner, thereby making it possible to reduce the amount of excess air passing through the com bustion chamber.' , . Conversion units are made in many sizes both round and rectangular to"' fit different types and makes of boilers and furnaces. They may be secured with manual, push button, or room temperature control. Sizing Gas-Fired Heating Plants While gas-burning equipment can be and usually is so installed as to be completely automatic, maintaining the temperature of rooms at a pre determined and set figure, there are in use installations which are manually controlled. Experience has shown that in order to effectively overcome the starting load and losses in piping, a manually-controlled gas boiler should have an output as much as 100 per cent greater than the equivalent standard cast-iron column radiation which it is expected to serve. Boilers under thermostatic control, however, are not subject to such severe pick-up or starting loads. Consequently, it is possible to use a 504 Chapter 28--Automatic Fuel Burning Equipment much lower selection, or safety, factor. A gas-fired boiler under ther mostatic control is so sensitive to variations in room temperatures that in most cases a factor of 25 per cent is sufficient for pick-up load. . The factor to be allowed for loss of heat from piping, however, must vary somewhat, the proportionate amount of piping installed being con siderably greater for small installations than for large ones. Consequently, a selection factor for thermostatically controlled boilers must be variable. Table'2 gives liberal selection factors to be added to the installed steam radiation under thermostatic control. They have been established by experience and are recommended by the American Gas Association. The same factors may be used in determining the gas demand for which conversion burners installed in steam or hot water boilers should be set. -Multiplying the equivalent direct heating surface (radiation), by 240 and .. adding the appropriate percentage from Table 2, and then dividing by the - heat value of the gas and by the heating efficiency (see discussion of Table 2. Selection Factors for Gas Boilers Cast-Iron Steam Radiation (Equivalent Square Feet) 500 800 1,200 1,600 2,000 3.000 4.000 and over Selection Factor (Per Cent) 56.0 54.0 51.0 48.0 45.0 42.5 40.0 neating efficiencies in Chapter 29), gives the proper hourly rate of gas consumption. However, inadequate boiler heating surface for gas burning, often encountered in coal-designed boilers converted to gas, miay necessitate operation at a lesser demand, resulting in much slower pick-up and less margin of safety for piping loss. Appliances used for heating with gas should bear the approval seal of the American Gas Association Testing Laboratory. Installations should be made in accordance with the recommendations shown in the publica tions of that association. . Ratings for Gas Appliances Since a gas appliance has a heat-generating capacity that can be pre dicted accurately to within 1 or 2 per cent, and since this capacity is not affected by such things as condition of fuel bed and soot accumulation, makers of these appliances have an opportunity to rate their product in exact terms. Consequently all makers give their product an hourly Btu output rating. This is the amount of heat that is available at the outlet of a boiler in the form of steam or hot water, or at the bonnet of the furnace in the form of warm air. The output rating is in turn based upon the Btu input rating which has been approved by the American Gas Asso ciation Testing Laboratory and upon an average efficiency which has been assigned by that association. 505 of andAmerican Society Heating Ventilating Engineers Guide, 1936 In the case of boilers, the rating can be put in terms of square feet of equivalent direct radiation by dividing it by 240 for steam, and 150* for water. This gives what is called the American Gas Association rating, and is the manner in which all appliances approved by the American Gas Association Laboratory are rated. To use these ratings it is only necessary to increase the calculated heat loss or the equivalent direct radiation load by an appropriate amount for starting and piping, and to select the boiler or furnace with the proper rating. . The rating given by the American Gas Association Laboratory is not only, a conservative rating when considered from the standpoint of capacity and efficiency, but is also a safe rating when considered from the standpoint of physical safety to the owner or caretaker. The rating that is placed upon an appliance is limited by the amount of gas that can be burned without the production of harmful amounts of carbon monoxide. This same limitation applies to all classes of gas-consuniing heating appliances that are tested and approved by the Laboratory. Gas boilers are available with ratings up to 14,000 sq ft of steam, while furnaces with ratings.up to.about 500,000 Btu.per hour are available. (See Chapter 23.) Installation Features . One feature of the piping installation that adds to the satisfactory service rendered by gas boilers is provision for adequate and rapid venting of the air from steam heating systems. If air leaks into the steam dis tribution system during the period that the gas is turned off, and then vents put slowly when the thermostat calls for heat, the result will be'a further cooling of the premises between the time that the thermostat calls for heat and the time that steam reaches the radiators. A freely venting steam or vapor system' gives maximum economyand minimum temperature variation. When gas boilers are attached to existing heating plants, it is good practice to check the effectiveness of the venting devices and if necessary to replace them with more effective ones that will prevent the return'd air into the heating system, and also to check the tightness of the piping. - Frequently when a coal boiler is already installed in a home, it is expedient ,to leave the coal boiler in place, and to cross-connect the gas boiler with it. Where gas heating is new to the community, it pro duces a more secure feeling in the customer's mind when putting in gasfired house-heating equipment, if-he knows that he can burn coal at any time he may desire. For steam or vapor installations, it is desirable to have the water line, in-both boilers at the same level1. * REFERENCES Stoker Information, Bulletin No. 5, Committee of Ten, 307 N. Michigan Avenue, Chicago, 111: 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). Intermittent Operation of Oil Burners, by L. E. Seeley and J. H. Powers (A.S.H.V.E. Transactions, Vol. 38, 1932).* 30 *A value of 160 for the heat emission of hot water radiators is used by many engineers. The actual heat emission, however, depends on the temperature of the water and of the surrounding air. See Chapters 30 and 33. Chapter 28--Automatic Fuel Burning Equipment Comparison of Oil and Gas Firing in a Heating Boiler, by L.-E. Seeley and E. J. Tavanlar (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, October, 1933). . 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). 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). " Oil Burning in Residences, by D. W. Nelson (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning, July, 1935). ' PROBLEMS IN PRACTICE | ' 1 What features of furnace.design are essential for the proper burning of the 1 . volatile coal gases above the fuel bed? " . . | l' Adequate provisions should be made so that the furnace.volume is sufficiently liberal and that the grates are a sufficient distance from the heating surfaces to permit the proper combustion of gasses. .. . . .: . .20 Classify stokers as to construction and operation. 1" o. Overfeed flat grate. '' 6.. Overfeed inclined grate. - . c. Underfeed side cleaning type. ' d. Underfeed rear cleaning type. . I 3 1 What classification may be made of stokers as to their use? ' ' . Class 1. For residences (Capacity less than 60 lb of coal per hour). . .. Class 2./For apartment houses and.small commercial heating jobs (Capacity 60 to 500 lb of coal per hour). - Class 3. For general commercial heating and small high pressure steam plants (Capacity 500 to 1200 lb of coal per hour). ,. Class 4. For large commercial and high pressure steam plants (Capacity over 1200 lb of coal per hour and over 36 sq ft grate area). . .' ' : 4 What main parts are found in an underfeed residential stoker? ;> K hopper is supplied to hold coal which is fed by a screw or plunger into a retort provided with air openings called tuyeres. A blower supplies air under pressure for combustion, and a gear case provides for changes in coal feeding rates. :' 5 0 What is a dead-plate? A dead-plate is a flat surface without air supply openings upon which the fuel rests while combustion of the fixed carbon is completed. Generally the ash is removed from the dead-plate. . . . ......................................... 6 A What rate of coal burning is usually recommended for small underfeed stokers? . ......... . - For continuous operation, 25 lb per square foot of grate surface is recommended; for short duration peaks, 30 lb, , . - . 7 0 What methods of. oil atomization are used? . 1. Throwing the oil from a rotating Cup or disc. 2. Forcing the oil under high pressure through a nozzle; 3. Propelling the oil with a high velocity jet of air or steam. 4. Forcing an oil and air mixture through a nozzle. 507 ' . of and 1936American Society Heating Ventilating Engineers Guide, 8 t What is the purpose of atomization? Atomization is used to increase the surface area of the oil in order to facilitate putting it into a vaporous state so it may burn. .9 Is the furnace of much importance in oil burning? . In most cases it is very important. It is the function of the oil burner to supply the air and fuel in correct proportions; the furnace must provide heated space for proper mixing and combustion. . . 10 ( Which flame is considered better, the luminous or the non-luminous? Laboratory tests show that they are equally efficient in the usual installation. 11 9 What main precaution is necessary in choosing a boiler for an oil burner? Since the burner output is usually varied through a wide range under control of the thermostat, a boiler should be provided with enough indirect heating surface to absorb:; the heat as it is released. The combustion space must be large enough, and:havecorrectr.' proportions for mixing fuel and air at high temperatures. If oil is used inefficiently high heating costs will result. " 12 How should oil burner adjustments be made? Adjustments should be made by an experienced man who uses a gas analysis apparatus to determine the C0% content. 13 What CO, content should be attained in oil burning? Ten per cent CO, is considered good practice, for it indicates the supplying of 50 per cent excess air. 14 What maximum heat release is considered good practice in oil burning? A heat release of 38,000 Btu per cubic foot per hour is considered to be the maximum for average large installations. This figure has been greatly exceeded in some cases. The design of the combustion chamber, as to impingement of flame and as to proper mixing at high temperatures, has much to do with the attainable heat release. 15 t Name five types of gas-fired space heaters. a. Parlor furnaces or circulators. b.. Radiant heaters. c. Gas-fired steam or hot water radiators. d. Warm air radiators. ' e. Garage heaters. ...... .. ' . . t 16 How are gas heating units rated? Gas-fired units are rated on the basis of output in Btu per hour. 17 What safety consideration is noted in establishing the ratings of gas-fired units? The rating is limited by the amount of gas that can be burned without the liberation of harmful amounts of carbon monoxide. ,' 18 List some factors which might account for possible economies of stoker firing over hand firing. a. The regular feed of coil instead of the intermittent feed. b. The use of cheaper sizes and grades of fuel. - c. The absence of door openings for firing purposes, which avoids the admission of cold excess air. d. The avoidance of overheating because the stoker responds quickly to automatic equipment controlled by. the heat demand. 508 Chapter 29 HEAT AND FUEL UTILIZATION Total Heat Loss Requirements, Utilization Factors, Degree-Day Methods, Base Temperature Determinations, Steam Consumption of Buildings, Fuel Consumption, Maximum Demands, Load Factors THE hourly heat loss (H) is equal to the sum of the transmission losses (Hi) and the infiltration losses (Hi) of the rooms or spaces to be heated. The total equivalent heating surface required is equal to ft. In estimating the fuel consumption of a building of more than one room divided by walls or partitions, it is not correct to use the calculated heat loss of the building without making the proper allowances for the fact that the heating load at any time does not involve the sum of the infiltration losses of all the heated spaces of the building but only part of the infiltration losses. This is explained in Chapter 6. It is sufficiently accurate in most cases to consider only half of the total infiltration losses of a building having interior walls and partitions. The value of H in Equation 1 would, under these conditions, be equal to Hi Ht + In some cases, where the building has no interior walls or 2' partitions, the infiltration losses are calculated by using only half of the total crack. In this case the entire infiltration loss should be considered. The heat required to warm the cold building and contents is a factor to be considered. Under certain conditions the cooling of the structure and contents will, to some extent, compensate for the heat required to rewarm the building. For example, if the building is under thermostatic control and the day and night temperatures are, 70 F and 50 F respectively, there will be a period during which no heat will be added while the building is cooling to 50 F, and the saving resulting therefrom will correspond to the additional heat required to bring the building and contents back to the daytime temperature. . HEAT AND FUEL CONSUMPTION There are two methods in use for estimating heat or fuel consumption. One method is theoretical, based on a calculated heat loss and assuming absolute constant temperatures for very definite hours each day through out the entire heating season. It does not take into account factors which are difficult to evaluate such as opening of windows, abnormal heating of the building, sun effect, poor heating systems, etc. . 509 American Society of Heating and Ventilating Engineers Guide, 1936 The second method is based on steam consumption data which have been taken from a group of buildings in operation, and the results com puted on a degree-day basis. While this method may not be as theo retically correct as the first mentioned method, it is of more value for practical use. Calculations of heat consumption made by the second method will invariably be higher than calculations made by the first method. Method 1 . ... . - ... . . . .. ' To predict the amount of fuel likely to be consumed in heating a building during a normal heating season, it is. necessary to know the total heat requirements of the building and the utilization factor of the. fuel. The accuracy of the estimate will depend on the ability'to select these. values and on the care taken in making allowances for other variable factors. ' Heat requirements are-given by the following general formula: H(t - fe) N M= fd -- (1) Steam requirements are determined by dividing the above by 1000, thus: . . _ H:jt -- fa) N .. . -. . " 0a - to) 1000 w Fuel requirements may be determined by the following formula: M .. F= CXE (3) where t = inside temperature,.degrees Fahrenheit. . ' . td = inside design temperature, degrees Fahrenheit. - . .. /a = average outside temperature, degrees Fahrenheit (Table 2, Chapter 7). to outside design temperature, degrees Fahrenheit. ... H = calculated heat loss of building based on outside temperature (fo), Btu per hour. N -- number of heating hours per season; 5088 from October 1 to May l1.. ' M heat loss, Btu per season. 5 = steam required to supply M Btu of heat loss. F = quality of fuel required per heating season. C = calorific value of one unit of fuel, the unit being the same as that on which F is based. ' E = efficiency of utilization of the fuel, percent. Example 1. A small factory building located in Philadelphia^ is to be heated to 60 F between the hours of 7 a.m. and 7 p.M.,.and to 50 F during the remaining hours. The calculated hourly heat loss based on a design temperature of --6 F is 500,000 Btu. If coal having a calorifiovalue of 12;500 Btu is fired and the overall heating efficiency is assumed to be 60 per cent, how many pounds of steam would be required for a normal heating season? `This is the period for which fa (Table 2, Chapter 7) ia calculated. If thejheating scascn'is'diflerent than this period, the corrected values may be substituted for .V and fa. 510 Chapter 29--Heat and Fuel Utilization Solution. Since there are no partitions in the building, the entire heat loss is con sidered. From Table 2, Chapter 7, the average outside temperature (fa) during the heating season is 41.9 F; N for the period for which fa is taken (October 1 to May 1) is 5088; H = 500,000; to = --6 F; t = 50 F and 60 F; fa - 60 F; 15 = 60 per cent average for heating season; C = 12,500. The average daily temperature for the 24 hours is: 50 X 12 + 60 X 12 -------------- 24--------------- = 55F Substituting in Equation 1: ,, 500,000 X (55 - 41.9) X 5088 M = ---------------- 60 -(-6)---------------- 504,942,000 f S = 504,942 lb of steam. F = o?xTi = 67-325 lb of coal = 337 tons- Method 2--Degree-Day Method The amount of heat required by 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. Some years ago the American Gas Association2 determined from experi ment in the heating of residences that the gas. consumption varied directly as the difference between 65 F and the outside temperature. In other words, on a day when the temperature was 20 deg below 65 F, twice as much gas was consumed as on a day when the temperature was 10 deg below 65 F. The degree day is defined in Chapter 44. Degree-days for -various cities in the United States and Canada are given in Table 1. Establishing the Base Inside Temperature. Recently the National . District Heating Association has studied the metered steam consumption of 163 buildings3 in 22 different cities and has published data substanti ating the fact that the 65 F base originally chosen by the gas industry is approximately correct. . The steam consumption of each building by months was divided by the number of days in each month, thus giving the average daily steam con sumption by months. The average steam consumption was then plotted against the average monthly temperature, as shown in Fig. 1, and the temperature at which a line drawn through the points crossed the base line indicated the temperature corresponding to zero steam consumption, or the base temperature. The composite results from 163 buildings calculated in this manner are shown in Table 2. The resultant average of 66.0 F is close to. the A.G.A. figure of 65 F. It will be noted that the base temperature calculated for hotels, apart ments and residences is consistently higher than those for such buildings as garages, auto sales buildings, and manufacturing buildings. This, of course, would be expected in view of the higher inside temperatures ^carried in the former group; in fact, an even greater difference would be *Sce Industrial Gas Series, House Heating (third edition) published by the American Gas Association. These buildings are all served with steam from a district heating company. American Society of Heating and-Ventilating Engineers Guide, 1936 Table 1. Degree-Days for Cities in the United States and Canada3 State ClTT . Jan. Feb. Mar. Apr. Mat Sept. Oct. Nov. Dec. Total Ain 589 577 428 311 Ariz.--......... Arlr 1153 969 459 325 Palif Col. . 719 326 San Francisco........ 465 Colorado Springs.. 1085 1079 582 266 356 993 918 Conn........... New Haven............ 1110 1011 nr Fla..... ......... Jacksonville........... 285 207 682 558 409 316 Idaho.-....... 1098 848 260 69 152 896 654 636b 292d 257 87 353 78 239 159 90 354 294 458b 502c 884 612 459b 162 799 .534 267 72 899 543 223 39 56 388 132 167 651 435 235 108 577 47 146 502 428 360 96 434 318 595 186 394 840 1128 252 465 381 651 123 301 261 428 789 1067 759 1017 693 1017 75 267 396 639 201 397 738 1011 111. In H Kans___ ..... Ky Tn Md. 1262 1095 909 549 248 30 353 756 1113 1180 1008 760 365 56 282 681 1038 949 854 640 276 155 528 862 1128 969 756 384 58 298 687 1017 1392 1173 890 429 118 357 798 1216 1434 1386 967 489 164 33 415 870 1265 1116 890 688 342 46 276 672 1004 1221 980 741 339 270 699 1051 974 867 648 342 25 245 612 903 939 801 589 264 186 552 849 332 230 58 102 301 1380 1232 1110 786 843b 566c 543 843 1228 1321 1168 1017 642 368 120 443 780 1153 955 843 700 348 22 . 223 567 875 1150 1042 908 570 245 48 363 693 1026 Mich--....... A/Tice Mn MoKw N. H. * N. J... N. M. . N. Y..J..... Nr c N. Dak___ 1253 1134 976 1501 1360 1249 1727 1473 1277 1609 1400 1095 520 384 195 1201 987 750 1060 654 657 1316 1120 955 1624. 1450 1168 573 226 42 804 682b 268d 810 722b 298d 570 235 93 321 15 276. 534 376b 189 630 513 270 1355 1125 868 414 84 1041 823 753 534 456b 144 1349 1240 1011 669 351b 168 Atlantic City.... 992 903 806 519 220 1014 942 735 402 81 1110 .902 775 543 301b 120 , Albany--.................. 1286 1142 980 .549 493 72 1240 1156 1032 675 347 75 1061 960 837 '486 155 1242" 1181 991 587 244 187 Raleigh.___............. 722 630 446 183 555 468 322 108 ' 400 777 1113 567 960 1301 .620 1062 1491 481 963 1405 252 471 285 605 1038' 205 597 936 524 909 1192 620 1041 1383 328 452 484 254 242 459 446 .418 276 426 130 19 780 1174 714 974 846 1234 588 893 588 930 780 1073 774 1147 774 1104 618 955 787 1140 429 694. 303 527 1 2408 1471 7145 1845 2665 2811 1504 3264 6553 5873 5895 4626 890 2891 1490 4558 4924 6315 .5370 4164 5297 6373 7023 5034 5301 4616 4180 1023 8531 7012 4533 6045 6464 6494 8692 9480 7851 1822 '5202 4585 7115 8699 6231 6128 5891 6852 5175 4934 6063 6889 6821 5348 .6785 3234 2302 8498 Heating and Ventilating Degree-Day Handbook. ^Including June. . clnchiding July and August, dlncluding August. 512 Chapter 29--Heat and Fuel Utilization Table 1. Degree-Days for Cities in the United States and Canada3 (Continued) State ClTT Jan. Feb. 1011 871 Cleveland. ......... 1180 1075 1113 980 Okla............ Oklahoma City___ 865 742 Portland.... ............ 806 644 Mar. 678 950 703 465 558 Apr. Mat Sept. 339 19 564 220 27 420 87 162 402 335b 105 Ocr. 248 366 313 105 332 Nov. Dec. 615 921 732 1060 690 1017 459 815 558 728 Pn Philadelphia........... 1001 895 756 402 68 242 588 903 1054 944 787 423 78 313 669 967 R. I................... Providence ....... 1116 1069 890 558 251 63 348 693 1026 Sr 487 372 242 36 725 688 431 147 207 425 121 429 716 744 599 384 96 812 747 476 180 62 402 663 136 483 744 366 277 65 381 274 74 1260 1072 893 Salt Lake City...... 1110 885 722 Vt - 1535 1294 1089 Va . 887 820 583 Norfolk......... "....... 738 650 520 Richmond............... 825 .702 552 Wash_____'. Seattle...................... 775 653 623 Spokane................... 1171 952 778 W. Va. 1026 944 713 525 376 114 453 234 18 654 276b 144 303 246 240 465 487b 276c 504 366 192 414 114 335 126 347 468 819 1218 388 723 1020 481 861 1286 223 549 878 99 411 685 158 483 765 403 570 716 514 819 1057 294 648 977 Wi<5 Wyo-........ 1507. 1321 1046 Green Bay. ............ 1538 1358 1125 LaCrosse.................. 1535 1265 1032 Milwaukee.............. 1383 1328 1023 Cheyenne................ 1215 1075 995 603 276 117 600 322 132 528 183 96 648 389b 84 720 569' 240 493 921 1328 505 921 1322 462 909 1280 449 846 1222 605 900 1143 Total 4702 6154 5323 3613 4468 4629 4855 5235 6014 1769 3257 7683 2950 3578 1578 2455 .1157 1202 6735 5553 7620 4243 3349 3725 4968 6353 5016 4884 7612 7823 7290 7372 7462 Province ClTT Jan. Feb. Mar. Apr. Mat Sept. Oct. Nov. Dec. Total B. C...... ... Victoria.................... Kamloops................ Alb.............. Sask............ Man............ Ont............. Port Arthur. Toronto Que............. 1615 1409 1219 Quebec...................... N. B........... Fredericton....!... N. S.................. Yarmouth................ P. E. I........... Charlottetown____ 720 309 190 5777 5976 6724 8152 11,261 11,166 10,803 7732 372 961 1422 8417 8628 9099 7694 8485 Heating and Ventilating Degree-Day Handbook. ' ^Including June. " Including July and August. . . 513 American Society of Heating and Ventilating Engineers Guide, 1936 Table 2. Base Temperature for the Degree-Day3 Tips or Buzldino No. or Buildings Analyzed 60 4 3 2 6 11 12 7 ' 14 8 4 5 3 2 2 4 3 3 2 8 Temperature F Cor responds to Zero Steam Consumption 66.2 65.8 66.2 65.5 67.4 64.0 64.3 66.5. 68.8 66.9 65.5 64.9 67.6 65.8 64.8 61.2 67.7 67.7 65.2 65.4 ' " . - i 66,0 F Report of Commercial Relations Committee, 193$ Proceedings, National District Beating Association. .' Table 3. Steam Consumption for Various Classes of Buildings3 (.Heating Season Only) Building Classification No. or Buildings Listed Steam Consumption Pounds per Degree-Dat--65 F Basis*) Per M Cu Ft Per M 8q Ft Per M Btu of Heated of Radiatorc per Hr of 8paoe Surface Heat Loe&b Apartments................................................................. Hotels. ................................... :...... .......................... Retail Stores.............................................................. Theatres...................................................................... Loft and Mfg............................................................. . Department Stores.......... :..............'....................... Garages (Storage)3 .................................. Offices (Total)____ --............................................... Offices (Heating only)........................................... . 16 10 12 7 10 1.8 6 16 7 -8 6 14 6 35 35 ,1.78 T.46 1.32 1.25 0.96 0.90 0.90 0.89 0.88 0.83 0.58 0.57 0.42. 1.09 0,975 97.5 80.6 64.2 105.5 77.0 80.6 75.0 72.3 45.2 62.2 49.4 ' 60,7' 72.3 70.0 65.4 . 0.359 0.371 0.268 0.498. 0.283 0.238 ____ J. 0:283 0.256 Includes steamfor heating domestic water for heating season only. Mieat loss calculated for maximum design condition (in most cases 70 F inside, zero outside).; . ^Equivalent steam radiator surface. . -. - dThe figures are a numerical--not a weighted-average for the several buildingB in each class. Based on zero consumption at 55 F. 514. Chapter 29--Heat and Fuel Utilization expected. For an average figure, the A .G.A. base of 65 F may therefore be safely used, and if greater refinement is desired, the figure for the type of building under consideration can be taken from Table 1. Table 36 gives, the steam consumption per degree-day, expressed in three different ways, for 196 buildings in 14 different classifications. These buildings are divided among 21 different cities in the United States. The steam used for heating the domestic water is included in these figures, but in the case of office buildings, the steam for heating only is also shown. The data are placed on a comparable basis by expressing the steam consumption in terms of pounds per degree-day per thousand square feet of equivalent installed radiator surface^ per thousand cubic feet of heated space, and per thousand Btu of calculated heat loss. ' " Fig. 1. Method of Determining Base Temperature for " Degree-Day Calculations4 The choice of these units of comparison require some explanation. ' The use of heated space in preference to the gross cubage used by architects' is obviously more accurate for this. purpose. The architect's cubage includes the outer walls and certain percentages of attic arid basement space which are usually unheated. The net heated space is usually about 80 per cent of the gross cubage and can be calculated from the latter if it cannot be measured. The cubical content is somewhat inaccurate as a basis of comparison due to differences in types of construction, exposure, and ratio of exposed area to cubical contents. ' The use of radiator surface as the basis of comparison has two ob jections. One is that the amount of radiator surface in a building is often either excessive or deficient, and figures for steam consumption based on it are therefore likely to be in error. Another reason is that it is difficult to convert fan coil surface into equivalent direct radiator surface with accuracy. On the whole, the use of radiator surface as the basis of com parison is the least satisfactory of the three methods. `Report of Commercial Relations Committee, 193$ Proceedings, National District Heating Association. The Heat Requirements of Buildings, by J. H. Walker and G. H. Tuttle (A.S.H.V.E. Journal Section, Heating, Piping and Air Conditioning. December, 1934). . 515 American Society of Heating and Ventilating Engineers Guide, 1936 It should be noted that the figures in Table 2 are for the heating season only and include steam for heating domestic water. Example 1 solved by the degree-day method and using values taken from Table 3 would show a higher steam consumption. Example 2. Factor for steam consumption for a manufacturing building per M Btu per hour heat loss per degree-day = 0.283; total number of degree-days per year (Table 1) = 4855; heat loss = 500,000 Btu per hour. Solution. 0.283 X 4855 X 500 = 686,982 lb of steam per year.. This calculation results in an estimate 36 per cent higher than the previous calculation and one which would be more nearly correct for actual practice. Chapter 29--Heat and Fuel Utilization unit, the consumption should be assumed as from 10 to 20 per cent greater. One reason for this difference in steam consumption is that district steam is a metered service, and building managers are therefore more conscious of their heating costs, which generally results in better maintained heating systems. Also, the district steam service is usually installed with ther mostatic control which reduces overheating to a minimum. Fig. 2 shows the amount of coal or oil that may be estimated when the steam consumption is known. Assuming the steam consumption that Fig. 2. Curve for Estimating Fuel Consumption for Various . Known Steam Consumption3 . , '- oThis curve is bused on heating efficiencies 'of 60 to 70 per cent for coal and oil, respectively, a calorific value of coal of 13,000 Btu per pound, a calorific value of oil of 140,000 Btu per gallon. . In case the heat loss figure is not known this method of estimating heat or steam consumption can also be applied if the net heated space figure is available. . . CALCULATION OF FUEL CONSUMPTION After the heat and steam consumption of the building have been calcu lated, the corresponding fuel requirements may also be-estimated by assuming the correct boiler and furnace efficiencies." If the building isjto be supplied with steam from a district heating company, the steam con sumptions as calculated by Methods 1 and 2 are generally assumed" to be correct; However, if the steam is to be supplied from an individual boiler 516 Fig. 3: Chart Giving Gas Requirements per Degree-Day for Various Calorific Values of Gas and for Different Heating Systems3 aThls chart is based on an inside temperature of 70 F and an outside temperature of zero. If the radia tion is installed on the basis of any other temperature difference, multiply the result obtained from this chart by 70, and divide by the actual temperature difference. From Industrial Gas Series House Heating (third edition) published by the American Gas Association. was calculated in Example 2, 686,982 lb, the corresponding coal con sumption, from the curve, is 44 tons and the oil consumption 6000 gal. Fig. 3 indicates the average gas consumption per degree-day for various heat contents. While the fuel consumption in individual cases may vary somewhat from the curve values, these average values are sufficiently accurate for estimating purposes and give satisfactory results. The value generally used in the manufactured gas industry for resi dences is 0.21 cu ft per degree-day per square foot of equivalent steam radiation (240 Btu) based on the theoretical requirements. A correction for warmer climates is necessary and it is customary to gradually increase the relative fuel consumption below 3000 degree-days to about 20 per cent more at 1000 degree-days. .. . American Society of Heating and Ventilating Engineers Guide, 1936 For hot water or warm air heat the fuel consumption is about 0.19 cu ft per degree-day per square foot of equivalent steam radiation, that is, per 240 Btu per hour. The actual requirements likewise relatively increase with hot water or warm air systems as the number of degree-days decreases below 3000. For larger installations, that is 1000 sq ft of theoretical radiation and above, there is an increase in efficiency, and a consequent decrease in the fuel consumption per degree-day per square foot of heating surface. The approximate quantities of steam required in New York City per square foot of heating surface for various classes of buildings are given in Chapter 37. . The preceding discussion on fuel consumption has dealt with the heating requirements of the building irrespective of any air that may be introduced for ventilation purposes other than the normal infiltration of outside air. The heat required for warming air brought into the building for ventilation may be estimated from data given in Chapters 3 and 22. . 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 instan taneous 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 available 'for a number of buildings in Detroit, as shown in Table 4. . ' These maximum demands were measured by an attachment on the condensation 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 Jag and to storage of condensate in the system, but wherever this has been investigated it has been found to be negligible. Table 4, Building Load Factors and Demands op Some Detroit Buildings*- Building Classification Load Factor Apartments....................................................................... -- 0.318 , 0.316 0.287 0.263 0.255 0.238 0.223 0.203 0.158 0.138 0.126 Lb' or Demand per Hb peb Sq Ft or Equivalent Installed Radiator Surface 0.184 0.207 0.217 0.209 0.225 0.182 . 0.248 .0.158 0.152 0.145 0.151 ` . `See Footnote 5 p. 515. The load factor of a building is the ratio of the average load to the maximum load and is an index of the utilization habits. Thus, in Table 4, Chapter 29--Heat and. Fuel Utilization the theatres, operating for short hours, have a load factor of 0.126 as compared with the figure of 0.318 for'clubs and lodges.. PROBLEMS IN PRACTICE 1 Is it correct to use the total calculated heat loss of a building for estimating fuel consumption? . No. The heating load does not generally involve the sum of the separate infiltration losses of the several heated spaces. When a building has interior walls and partitions it is sufficiently accurate to consider only half of the total calculated infiltration losses. 2 What will be the 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 heating efficiency will be 75 per cent. The heating plant will be thermostatically controlled, and a temperature of 55 F will be maintained from 11 p.m. to 7 a.m. Assume that the price of gas is 7 cents per 100,000 Btu of fuel consumption, and disregard the loss of heat through open windows and doors. The average hourly temperature is (72 X 16) + (55 X 8) = 66.3 F. . 24 The maximum hourly heat loss will be ' . 92.000 - 2-6' = 79,000 Btu = H. 79,000 (66.3 - 36.4) X 24 X 210 M= 100,000 X 0.75 .X (72 - 0) = 2204.6 hundred thousand Btu. 2204.6 X 0.07 = $154.34 = cost per year of heating the building. 3 What factors should be taken into consideration when determining the efficiency at which a fuel will be burned? ' Manufacturers' catalogs usually give equipment efficiencies obtained under test con ditions. These values do not allow for poor attendance, defects in installation, or poor draft. Suqh efficiencies do not consider heat radiated from the outside of the equipment, but in many cases this heat is utilized. ' 4 If 20 tons of coal having a calorific value of 13,000 Btu per pound are burned in a'Warm air furnace and produce 286,000,000 Btu at the bonnet, what is the efficiency of the furnace? 1* ;____________ Number of Btu at bonnet_______ ___________ Number of tons X calorific value X number of lb in one ton = efficiency. 286,000,000 X 100 ,, 20 X 13,000 X 2000 55 per -cent 5. In making degree-day calculations, why is the base of 65 F used for an in side temperature of 70 F? . Thisbase was chosen because data collected from numerous installations show that heat is seldom supplied to a residence when the outdoor temperature is greater than 65 F. It 'i^S j-lr* ^oun<I that the amount of fuel consumed varied in almost direct proportion with the difference between 65 F and the outside temperature. . 519 American Society of Heating and Ventilating Engineers Guide, 1936 6 Use the degree-day method of computing the amount of coal required to ' heat an office building located in Cleveland, Ohio, assuming that the net, heated space is 30,000 cu ft. The steam consumption factor for office buildings is 0.975 pounds per M cu ft per degreeday (Table 3). Cleveland has 6154 degree-days per year (Table 1). 0.975 X 6154 X 30 = 180,000 lb of steam. From Fig. 2, this is equivalent to 13 tons of coal. 7 # Make a rough approximation of the gas required to heat a building located in Chicago, 111., assuming that the calculated heating surface requirements are 1000 sq ft of hot water radiation based on design temperatures of 0 F and 70 F. Chicago has 800-Btu mixed gas, and 6315 degree-days. Using Fig. 2, the fuel consumption for a design temperature of 0 F with 800-Btu gas is found to be 0!08 cu ft of gas per degree-day per square foot of hot water radiation. . ' ' 0.08 X 6315 X 1000 = 505,200 cu ft. ,. 8 A certain building has a maximum heat loss of 250,000 Btu per hour in --15 F weather. How many tons of fuel will be required to maintain a temperature of 70 F during a 260-day heating season in which the average temperature is 39 F? . The heating value of the fuel is 13,200 Btu per pound and the efficiency of com bustion is 60 per cent. 250,000 (70 - 39) 260 X 24 _ _ . ,(70 + 15) 13,200 X 0.60 X .2000 . 9 # Which item may be determined more closely, the heating value of a fuel or the efficiency of its combustion? The heating values of oil, gas, and solid fuels are closely determinable, whereas the : efficiency of burning depends on the particular equipment chosen and the skill used in handling it. 10 In an office building, the thermostats are set to maintain 70.F from 7"a.m. to 5 p.m. and 50 F during the rest of the time. When the outside temperature is 30 F, how much saving might be expected because the temperatures are i lowered? Under the above conditions the building becomes 50 F by 11 p.m. and warms up to 70 F by 8 a.m. ' A temperature of 70 F is maintained.during 9 hours, and one of 50 F during 8 hours; the temperature would average about 60 F during the 7 hours required for cooling down and warming up. ' The average is 60.4 for the-24 hours. (The average temperature calcu lated would have been 58.3 F, had the warming and cooling periods been neglected.) The saving is X 100 = X 100 = 24 per cent. . . 11 How does the heat capacity of a structure influence the saving made by carrying lower temperatures during the night? , The heat storage capacity of the walls prevents rapid dropping of temperatures at night time and delays the warming up process in the morning. In an extreme case, the building would not reach the lowered temperature by the time the higher temperature is called for in the morning. But under any conditions, the saving made by lowering the tem perature can be correctly estimated by using the average temperature observed over the 24-hour period as a factor, as in Question 10.12 12 9 What are some of the: miscellaneous factors' that 'may cause actual fuel consumption to vary from the theoretical fuel requirements as calculated, by the use of heat losses, temperature difference, and fuel burning efficiency? The opening of windows; abnormally high or low inside temperatures; other sources of heat, such as machinery or lights; sun effect; and unusual winds. 520 Chapter 30 RADIATORS AND GRAVITY CONVECTORS Heat Emission of Radiators and Convectors, Types of Radiators, Output of Radiators, Heating Effect, Heating Up the Radiator, Enclosed Radiators, Convectors, Selection, Code Tests, Gravity- . Indirect Heating Systems THE accepted terms for heating units are: (1) radiators, for direct surface heating units, either exposed, enclosed, or shielded, which emit a large percentage of their heat by radiation; and (2) convectors, for heating units having a large percentage of extended fin surface and which emit heat principally by convection. Convectors are dependent upon enclosures to provide the circulation by gravity of large volumes of air. HEAT EMISSION OF RADIATORS AND CONVECTORS All heating units emit heat by radiation and convection. The resultant heat from these processes depends upon whether or not the heating unit is exposed or enclosed and upon the contour and surface characteristics of the material in the units. An exposed radiator emits less than half of its heat by radiation, the . amount depending upon the size and number of sections. When the radiator is enclosed or shielded, radiation is further reduced. The balance of the emission is by conduction to the air in contact with the heating surface, and the resulting circulation of the air warms by convection. A convector emits practically all of its heat by conduction to the air surrounding it and this heated air is in turn transmitted by convection to the rooms or spaces to be warmed, the heat emitted by radiation being negligible. . TYPES OF RADIATORS Present day radiators may be classified as tubular, wall, or window types, and are generally made of cast iron. Catalogs showing the many designs and patterns available now include a junior size which is more compact than the standard unit. . Pipe Coil Radiators Pipe coils are assemblies of standard pipe or tubing (1 in. to 2 in.) which are used as radiators. In older practice these coils were commonly used jii factory buildings, but now wall type radiators are most frequently used for this service. When coils are used, the miter type assembly is to be 521 American Society of Heating and Ventilating Engineers Guide, 1936 preferred as it best cares for expansion in the pipe. Cast manifolds or headers, known as branch tees, are available for this construction. OUTPUT OF RADIATORS The output of a radiator can be measured only by the heat it emits. The old standard of comparison used to be square feet of actual surface, but since the advance in radiator design and proportions, the surface area alone is riot a true index of output. (The engineering unit of output is now the Mb or 1000 Btu.) However, during the period of transition from the old to the new, radiators may be referred to in terms of equivalent square feet. For steam service this is based on an emission of 240 Btu per hour per square foot. Table 1. Variation in Dimensions and Catalog Ratings of 10-Section Tubular Radiators No. of Tubes Width of Radiator Length per Section Inches 3 ________ Inches . 4.6-5.1 2.5 4 6.0-7.0 2.5 . '5 . 6 8.0-8.9 2.5- 9.1-10.4 2.5 7 11.4-12.8 2.5-3.0 ' Height with Leas--Inches Heat Emission-- Equivalent Squabs Feet .. . . 13-14 16-18 20-21. 22-23 25-26 30-32 36-38 - 20 25.0-32.5 28.5 30.0-38.3 . 15.0-17.5 20.0-22.5. 25.0-31;2 .30 36.7-45.0 20.0-21.3 25 30.0-33.9 35 . 40.0-45.2 20.0-26.7 25.0-27.5 32.5-39:8 37.5-40.0 50.0-53.5 25.0-30.9 33.3-35.0 40.0-48.6 50 63.3-62,5 30.0-36.7 40.0-42.5 50.0-56.5 60 70.0-75.4 Output.of Tubular Radiators . . Table T illustrates the difficulty iri tabulating tubular radiator outlets since there is so much variation iri design between the products' of the different manufacturers. Only on the:four-tube and six-tube sizes is there any practical agreement in output value. The heat emission values appear as square feet but are entirely empirical, being based on .the heat emission of the.radiator and not on th measured surface. ` Output of Wall Radiators ' An average value of 300 Btu per actual square; foot of surface area per hour has been found for wall radiators one section high placed'with their bars vertical. Several recent tests1'show that this value will be reduced from 5 to 10 per cent if the radiator is placed near the ceiling with the bats horizontal and in an air temperature exceeding 70 F. When; radiators are placed near the ceiling, there is usually sp noticeable a difference in temperature.- between the floor level and the ceiling that it becomes dif ficult to heat.the living zone of a room satisfactorily, . : ......... lUniver3ity of Illinois, Engineering'Experiment.Station Bulletin No. 223," p. 30. 522 Chapter 30--Radiators and Gravity Convectors Output of Pipe Coils The heat emission of pipe coils placed vertically on a wall with the pipes horizontal is given in Table 2. This has been developed from avail able 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 of ceiling coils, placed horizontally, is about 126 Btu, 156 Btu, and 175 Btu per linear foot of pipe, respectively, for 1-in., lj^-in., and lJ/-in. coils. . Table 2. Heat Emission of 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) Sm or Pips . Single row................................................... *"prun t ii ___ _____ .........______ ______ Four.------------- i-----------------------------------Six.____ ___ ---------------------------------------Eight------------ --....................................... Ten-------------------- ------------ ----- --------------Twelve. 1 In. 132 252 440 567 651 732 812 Hi I"- 162 312 545 702 .796 907 1005 . 1M In 185 348 616 793 907 1020 1135 Effect of Paint ' ............... The prime coat of paint on a radiator has little effect on the heat output, but the finishing coat of paint does influence the radiation emission. Since this is a surface effect, there is no noticeable change in the convection loss. Thus, the larger the proportion of direct radiating surface, the greater will be the effect of painting on the radiation. Available tests are on oldstyle column type radiators which gave results shown in. Table 3. Table 3. Effect of Painting 32-in. Three Column, Six-Section Cast-Iron Radiator3 1. Radiator No. i 2 3 4 Finish Bare iron, foundry finish___________ One coat of aluminum bronze______ Gray paint dipped ________________ One coat dull black Pecora paint__ Abba Sq Ft 27 27 27 27 CosmeXENT Relative or Heat Trans. Heating Value Btu Peb Cent 1.77 1.60 1.78 1.76 100.5 90.8 101.1 100.0 Comparative Tests of Radiator Finishes, by W. H. Sevems (A.S.H.V.E. Transactions, Vol. 33,1927). Effect of Superheated Steam ... . .. Available research data indicates that there is probably a decrease in heat transfer rate for a radiator or gravity convector with superheated steam in comparison with saturated steam at the same temperature. The decrease, is probably small for low temperatures of superheats and additional 'tests are necessary with varying degrees of superheat to establish accurate comparisons for all types of radiators and. convectors2. ,lunUrt!lT, eps.t20o6L)R. ad' iator9 Super-heated Steam, by R. C. Carpenter (A.S.H.V.E. Transactions, , ' Vol.'7, 523  American Society of Heating and Ventilating Engineers Guide, 1936 HEATING EFFECT For several years the heating effect of radiators has been considered by engineers in order to use it for the rating of radiators and in the design of heating systems. Heating effect is the useful output of a radiator, in the comfort zone of a room, as related to the total input of the radiator3. 2 3 4 fb 7 B Height Above Floor in Feet Fig. 1. Room Temperature Gradients and Steam Condensing Rates for Four Types of Cast-Iron Radiators with a Common Temperature at the 60-In. Level Note that the steam condensations are practically the same for all four radiators when the same air temperature of.69 F is maintained at the 60-in. level. Chapter 30--Radiators and Gravity Convectors 1. The heating effect of a radiator cannot be judged solely by the amount of steam condensed within the radiator. 2. Smaller floor-to-ceiling temperature differentials can be maintained with long, low, thin, direct radiators, than is possible 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 breathing 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 window ' openings5. , HEATING UP THE RADIATOR " The maximum condensation occurs in a heating unit when the steam " is first turned on. Fig. 3 shows a typical curve for the condensation rate in pounds per hour for the time elapsing after steam is turned into a castiron radiator. The data are from tests on old style column type radiators. . .345*70? Height Above- Floor in Feet Fig. 2. Room Temperature Gradients and Steam Condensing Rates for Four Types of Cast-Iron Radiators with a Common Temperature at the.30-In. Level Note that the steam condensations are different for all four radiators when the same air temperature of 68 F is maintained at the 80-in. level. -. The results of tests conducted at the University of Illinois are shown in Figs. 1 and 24. For the four types of radiators shown, the following con clusions are given: . The Heating Effect of Radiators, by Dr. Charles Brabbee (A.S.H.V.E. Transactions, Vol. 33. 1927. R. 331. `Steam Condensation an Inverse Index of Heating Effect, by A. P. Kratz and M. K. Fahnestock (A.S.H.V.E. Transactions. Vol. 37, 1931). 524 Time elapsing after Steam is turned into Radiator (in Minutes) Fig. 3. Chart Showing the Steam Demand Rate for Heating Up a Cast-Iron Radiator with Free Air Venting and Ample Steam Supply In practice 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. Automatic control valves may also retard the supply of steam. 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 heating effect. Recent investigations6 indicate that in the design of the enclosure three things should be considered: 'Effect of Two Types of Cast Iron Steam Radiators In Room Heating, by A. C. Willard and M. K. Fahnestock (Heating, Piping and Air Conditioning, March, 1930). University of Illinois Engineering Experiment Station Bulletins No. 192 and 223, and Investigation of Heating Rooms with Direct Steam Radiators Equipped with Enclosures and Shields, by A. C. Willard, a. h. Kratz. M. K. Fahnestock and S. Konzo (A.S.H.V.E. Transactions, Vol. 35, .1929). .. 525 American Society of Heating and Ventilating Engineers Guide, 1936 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 heating performance. 3. The enclosed radiator may inadequately heat the space. A comparison between a bare or exposed radiator (A) and the same radiator with a well-designed enclosure (B), with a poorly-designed enclosure (C), and with a cloth cover (D) will illustrate the relative heating effects. In Fig. 4 the curve (J3) reveals that the enclosed radiator used less steam than the exposed radiator, but gave a satisfactoiy heating performance. A well-designed shield placed over a radiator gives about the same heating effect. Curve (C) shows the unsatisfactory effects produced by improperly designed enclosures. Curve (D) shows that the Chapter 30--Radiators and Gravity Convectors room by convection thereby resulting in a form of gravity convector, generally better results are obtained with specially designed units which permit a free circulation of a larger volume of air at moderate tempera tures. Since air stratifies according to temperature, moderate delivery temperatures at the outlet of the enclosure reduce the temperature dif ferential between the floor and ceiling and accordingly accomplish the desired heating effect in the living zone. Fig. 5 shows a typical built-in convector. The heating element con sisting of a large percentage of fin surface is usually shallow in depth and effect of a cloth cover extending downward 6 in. from the top of the radiator was to make the performance unsatisfactory and inadequate. Practically all commercial enclosures and shields for use on direct radiators are equipped with water pans fdr the purpose of adding moisture to the air in the room. Tests7 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 the radiator is steam hot and the relative humidity in the room is between 25 and 40 per cent. This sOurce of supply of moisture alone is not adequate to maintain a relative humidity above 25 per cent on a zero day. CONVECTORS OR CONCEALED HEATERS Although any standard radiator may be concealed in a cabinet or other enclosure so that the greater percentage of heat is conveyed to the 'University of Illinois Engineering Experiment Station Bulletin No. 230, p. 20. 526 t Fig. 5. Typical Concealed Convector Using Specially Designed Heating Unit placed low in the enclosure in order to .produce maximum chimney effect in the enclosure. The air-enters the-enclosure near.the floor line just below the heating element,- is moderately heated in passing through the core and delivered, to the room through an opening near the top of en-. closure. Since the air can only enter the enclosure at the floor line, the cooler.air in the room which always lies.at this level,.is constantly being withdrawn and replaced by the warmer air. This air movement accom plishes the desired reduction in temperature differentials and assures maximum comfort in the living zone. ' . . The Convector Manufacturers Association has adopted the A.S.H.V.E. Standard8 in the formulation of its ratings and has compiled a tentative fAtiHvn1 (A.S.H.V.E. TransaZctions, Y7 , Vol. ,,,, 37. .XiMr8,. u 1931), (Hot Ivaun* Water). v(oAn.cSe.Hai.eVa.Eg. rTarvaitnysalcytpioensK,aVaoialu. o3n9. (Steam 1933). 527 of andAmerican Society Heating Ventilating Engineers Guide, 1936 standard of heating effect allowances for various enclosure heights to be included in the ratings by its members. ' All published ratings bearing the title C.M.C. ratings (Convector Manu facturers Certified Ratings) indicate that the convectors have been tested in accordance with the A.S.H.V.E. code by an impartial and disinterested laboratory and that the ratings have been approved by the Standardiza tion Committee of the Convector Manufacturers Association. Concealed heaters or convectors are generally sold as completely built-in units. The enclosing cabinet should be designed with suitable air inlet and outlet grilles to give the heating element its best performance. Tables of capacities are catalogued for various lengths, depths and heights, and combinations are available in several styles for installations, such as the wall-hung type, free-standing floor type, recess type set flush with wall or offset, and the completely concealed type. Most of these types may be arranged with a top outlet grille in a plane parallel with the floor, although the front outlet is practically standard. 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 impor tant that the enclosure or housing for the convector fit as snugly as pos sible so that the air to be heated must pass through the convector and cannot be by-passed in the enclosure. .~ The output of a convector, for any given length and depth, is a variable of the height. Published ratings are generally given in terms of equiva lent square feet, corrected, for heating effect. However, an extended surface heating unit is entirely different structurally and physically from a direct radiator and, since it has no a'rea measurement corresponding to the heating surface of a radiator, many engineers believe that the per formance of convectors should be stated in Btu's.. For steam convectors, as for radiators, 240 Btu per hour may be taken as an equivalent square foot of radiation. -> . RADIATOR AND CONVECTOR SELECTION Since the capacity of a radiator8 varies as the 1.3 power and a con vector8 9 as the 1.5 power of the temperature difference between the inside of radiator and surrounding air it is obvious that for other than 70 F room temperatures the heat emission will be other than 240 Btu per square foot of rating. Therefore in seTfecting the size of radiator or con vector to be used it is necessary to correct for this difference. Table 4 shows factors by which radiation requirements, as determined by dividing heat load by 240, shall be multiplied to obtain proper radiator or con vector sizes from published rating tables for room temperatures ranging between 66 and 80 F as well as for 1 and 2 lb per square inch gage steam pressures. For other room and heating medium temperatures the factor is determined by the following formulae: For radiators: ,, /215 - 70\i.3 . Q " V k ~tT ) Factors Affecting the Heat Output of Convectors, by, A. P. Kratz, M. K. Fahnestock, and E. L. Brod erick (A.S.H.V.E. Transactions, Vol. 40, 1934). . 528 Chapter 30---Radiators and Gravity Convectors For convectors: /215 - 65\i-s \ k-k ) where Cs = correction factor. ts = temperature of heating medium. tT = room temperature. Table 4. . Correction Rating Factors A! . . " Room Temperature DEO F Steam Pressure Lb per Sq In. Gage 66 68 70 72 74 76 78 80 Correction Factor 0.96 0.98 1.00 1.02 1.04 1.06 1.08 1.10 0.92 0.94 0.96 0.98 1.00 1.02 1.04 1.06 CODE TESTS FOR RADIATORS AND CONVECTORS As previously indicated, the output of radiators and convectors is still designated by the terms of older practice, but this is gradually giving place to an engineering method of designating heat emission. The A.S.H.V.E. has adopted the following standards: Code for Testing Radiators (1927) ; Codes for Testing and Rating Concealed Gravity Type Radiation (Steam, 1932, and Hot Water, 1933). . For steam services the actual condensation weight is taken without any allowance for heating effect; for hot water services the weight of circulated water is used without allowance for heating effect. In all cases the total heat transmission varies as the 1.3 power for radiators8 and the 1.5 power for convectors8 9 of the temperature difference between that inside the radiator and the air in the room, and is expressed in Btu or Mb per hour. Standard test conditions specify either a steam pressure of 1 lb gage (215 F), or hot water at 170 F and a room temperature of 70 F for radi ators, or an inlet air temperature of 65 F for convectors. The heating capacity of a steam radiator or steam convector is determined as follows: where Ht ~ Wahig . (1) Ht = Btu per hour under test conditions! Wa = condensation in lb per hour. hfg = latent heat in Btu per lb. - Ht may be converted to standard conditions of code.ratings, by using the proper correction factor from the following formulae: 529 American Society of Heating and Ventilating Engineers Guide, 1936 For radiators: ,, /215 - 70\l-3 -8 ~ V T. - Tr ) ( 145 Y V T - Tt ) For convectors: /215 - 65y-5 ~ \T,-Ti) / 150\ \Ta-Ti) (2) (3) The output under standard conditions will be: where Hs = CaHt ... ................... Cs = correction factor. . Ta = steam temperature during test, degrees Fahrenheit. Tr -- room temperature during test, degrees Fahrenheit. 7| inlet air temperature during test, degrees Fahrenheit. . Ha -- heat emission rating under standard conditions, Btu per hour. (4) ........ Similarly, for hot water convectors, the output under test conditions may be determined as follows: ................................ H=W (0, - 0,)' " . ' (5) where : H = Btu per hour under test conditions. ' W = pounds of water handled during test. 8i = average temperature of inlet water, degrees Fahrenheit. 6i = average temperature of outlet water, degrees Fahrenheit. - ( = duration of test, seconds. To convert test results to standard conditions, the following correction factor is used: . '' . C= . ~ (6) It has been shown that when the expbnent 1.5 is used the range of error is less than 3 per cent9 for convectors. GRAVITY-INDIRECT HEATING SYSTEMS19 '' The heating units for this system are usually of the extended surface type for steam or hot water, and are1 installed about as shown in Fig. 6. The temperature and volume of the air leaving the register must be great enough so that in cooling to room temperature the heat available will just equal the heat loss during the same time. In cases where ventilation is a "For further information on this subject see A.S.H.V.E. Code of Minimum Requirements for the Heating and Ventilation of Buildings (edition of 1929) and Mechanical Equipment of Buildings, by Harding and Willard, Vol. I, second edition, 1929. ^ ' 530 Chapter 30--Radiators and Gravity Convectors requirement, the air volume needed may become so large that the entering air temperature will be but slightly above the room temperature. To establish and maintain a constant heat flow, provision must be made for removing the air in the room, after it has cooled to the desired room tem perature, by a system of vent flues or ducts. As the air flow is maintained Fig. 6. Gravity-Indirect Heating System3 See Mechanical Equipment at Buildings, by Harding and Willard, Vol. I. second edition, 1929. by natural draft and this gravity head is very slight, it is necessary to make all ducts as short as possible, especially the runs from the heating units to the base of the vertical warm air flues. Gravity-indirect arrange ments, such as illustrated in Fig. ,6, are not to be generally recommended for hot water systems unless the water temperature can be maintained at a reasonably high temperature and rapid circulation of the water can'be had. ` PROBLEMS IN PRACTICE 1 what is the effect on the heat output of a wall radiator when installed on the ceiling of a room? Because the temperature differential is increased between the floor level and the ceiling when a wall radiator is placed near the ceiling, the heat output may be decreased from 5 to 10 per cent. Under such circumstances it becomes difficult to heat the living zone of a room satisfactorily. 531 American Society of Heating and Ventilating Engineers Guide, 1936 2 What are the principal differences between a radiator and a convector? A radiator is commonly thought of as a commercial heating unit having a maximum amount of direct heating surface, whereas a convector is a heating device in which the extended or secondary surface may be several times that of the prime surface and which is specially designed to utilize to the fullest extent the convection principal of heating. The radiator ordinarily has vertical tubular chambers for the heating medium but1 most convectors have horizontal tubular chambers to which fins are attached so as to form vertical flues for the passage of air. While radiators are either exposed, enclosed, or shielded, convectors are concealed by means of a tight-fitting enclosure. Radiators are ' commonly made of cast-iron but convectors may be made of a combination of metals, such as copper and brass, or copper and aluminum, as well as entirely of cast iron. 3 How did the term heating effect come into use? It has been found that a room requiring a radiator of a certain determined capacity could under certain conditions be properly heated, with less temperature gradient be tween floor and ceiling and with less steam condensation, by the same radiator or by one of a different design having the same commercially rated capacity. This resulted in the use of the term heating effect to apply to the useful heat output of a radiator, in the com fort zone of a room, as related to the total input to the radiator. 4 Is it necessary to make any allowance for the performance of a convector because it is enclosed? No. The commercial ratings of convectors have been determined by testing the con vectors in proper enclosures with grilles in place just as they should be installed for ordinary service. " 5 On what basis are the capacities of convectors published? Published ratings of convectors are on the basis of equivalent square feet of direct exposed cast-iron. If any allowance is made for heating effect, the amount of such allowance is generally stated in the manufacturers' catalogs. . 6 How are fins of convectors attached to the tubes or prime surface? Tubes or a solid core may be forced through piercings in the fins under pressure, or the tubes may be expanded into the holes through the fins. In addition a metallic bonding agent is sometimes used to insure permanent contact. 7 What is the procedure in selecting a convector when the required amount of radiation is known? First the limiting factor or factors of the enclosure must be determined so the available size of the wall recess can be found. Manufacturers' catalogs show capacities of con vectors of each standard length and depth with varying enclosure heights. From these capacity tables, the proper convector of the required capacity can be selected for the available wall recess. If all three dimensions of the wall recess are insufficient to accom modate a convector of the required capacity, the available height and length can be maintained, but greater depth can be obtained by using a partially recessed enclosure. ' 8 Given a room to be heated to 80 F with outside temperature at zero F. Assume the heat loss under these conditions tb.be 10,000 Btu per hour. Deter mine the size of the steam radiator to be installed. j A square foot of radiation is equivalent to a heat emission of 240 Btu per hour tinder standard conditions of steam at one pound gage pressure (215 F) and surrounding air at 70 F. With surrounding air at &0 F, the heat emission from a radiator will be less. Under these conditions, the heat emission will not be 240 Btu per square foot of catalog rating per hour, but 240 Cs. . (ts - ft)1-1 = (215 - 80)- Ct (215 - 70) (215 - 70) ' and 240 Ca = 240 X 0.912 = 218.5 Btu. Therefore, the size of the radiator to be selected shall have a catalog rating of 10,000 divided by 218.5 or 45.8 sq ft. . 532 Chapter 31 STEAM HEATING SYSTEMS Gravity and Mechanical Return, Gravity One-Pipe Air-Vent System, Gravity Two-Pipe Air-Vent System, One-Pipe Vapor / System, Two-Pipe Vapor System, Atmospheric System, Vacuum System, Sub'Atmospheric System, Orifice System, Zone Control, . Condensation Return Pumps, Vacuum Pumps, Traps - THE essential features of the common type of steam heating systems are described in this chapter. They may be classified according to the piping arrangement, the accessories used, the method of returning the con densate to the boiler, the method of expelling air from the system, or the type of control employed. Information concerning the design and layout of steam heating systems will be found in Chapter 32. GRAVITY AND MECHANICAL RETURN In gravity systems the condensate is returned to the boiler by gravity due to the static head of water in the return mains. The elevation of the, boiler water line must consequently be sufficiently below the lowest heating units and steam main and dry return mains to permit the return of condensate by gravity. The water line difference1 must be sufficient to overcome the maximum pressure drop in the system and, when radiator and drip traps are used as in two-pipe vapor systems, the operating pressure of the boiler. This applies only to closed circuit systems, where the condensation is returned to the boiler. If the condensation is wasted, no water line difference is required. In mechanical systems the condensate flows to a receiver and is then forced into the boiler against the boiler pressure. The lowest parts of the supply side of the system must be kept sufficiently above the water line of the receiver to insure adequate drainage of water from the system, but the relative elevation of the boiler water line is unimportant in such cases except that the head on the pump or trap discharge becomes greater as the height of the boiler water line above the trap or pump increases. There are three general types of mechanical returns in common use, namely, (1) the mechanical return trap, (2) the condensation return pump, and (3) the vacuum return pump. Further information on pumps and traps will be presented later in this chapter. GRAVITY ONE-PIPE AIR-VENT SYSTEM In the gravity one-pipe air-vent system each radiator has but a single connection through which steam must enter and condensation must u'aler t*ne difference is the distance between the water line of the boiler and the level of the water in the dry or wet return main. (See Fig. 4.) . .. 533 American Society of Heating and Ventilating Engineers Guide, 1936 return in the opposite direction. Each radiator has an individual air valve. Up-Feed Gravity One-Pipe Air-Vent System This system is the most common of all methods of steam heating, especially for small size installations, due largely to its low cost of instal lation and its simplicity. Where the size of the system is moderate or large, it cannot be assumed that these systems will be lower in cost than two-pipe systems using steam traps. In some instances it has been found that the cost of one-pipe systems under these conditions is greater owing to the higher cost of labor and materials due to the larger pipe sizes. As will be seen from Fig. 1, the steam piping rises to a point as high as possible at the boiler and pitches downward from this location until the far end of the main or mains is reached. At the far ends drips are taken off at the low points of the steam mains, are water-sealed below the boiler water line, and then brought back to the boiler in a wet return. Single pipe risers are branched off the main or mains to feed the radiators, the steam passing up the riser and the condensation flowing down it. The steam and con densation flow in opposite directions in the riser but after the condensa tion enters the steam main it flows in the same direction as the steam and is disposed of through the drip connection at the end of the main. In buildings of several stories, it is customary , to. drip the heel of each riser separately, whereas in one- or two-story buildings this is not necessary. Both types of branches and risers are shown in Fig. 1. Rapid elimination of air and condensation from the steam piping is essential to the successful operation of this system. It is therefore desirable that the venting and dripping of the steam main in long runs be 634 Chapter 31=--Steam Heating Systems made at several intermediate points where the steam main may again be brought to a higher elevation. . It is desirable to install the air vent valves on the steam main.about a ' foot ahead of the drips, as is indicated in Fig. 1 to prevent possible damage to the mechanism of the air vent valve by water, in case the valves are installed directly above the drips. Horizontal branches to radiators and risers should be pitched at least y2 in. in 10 ft downward toward the riser or vertical pipe, and the hori zontal branches from the steam main should be graded at least this amount toward the main, except where the heel of the riser is dripped, in i which case the branch should pitch down toward the riser drip (Figs. 2 and 3). The return line, if wet, may be run without pitch or may be .pitched in either direction, but if it is necessary to carry the return main . overhead for any distance before dropping, the return should slope down ward with the flow. It is desirable to install the wet return pipe with a Up to radiator or riser Pitch main --5 ft approximately Fig. 2. Typical Steam Runout where Risers are not Dripped Fig. 3. Typical Steam Runout where Risers are Dripped pitch so that the system may be drained to prevent freezing in case the building remains unoccupied for a considerable length of time. . The radiator valves may be of the angle-globe or gate type.- They should not be of the straight-globe type because the damming effect of the raised valve seat interferes with the flow of condensation through' the valve. Graduated valves cannot be used, as the steam valves on this system must be fully open or closed to prevent the radiators filling with water. Air valves may be manual or automatic, with or without a check to prevent the re-entrance of expelled air. Usually the 'automatic type is installed. An objection to one-pipe steam systems is that the heat is all on or all off, with no intermediate position possible. However, intelligent use of the on-and-off method of manual control gives reasonably satis factory results. Improved systems and devices are now available which make it possible to . obtain a modulating effect from one-pipe: gravity heating systems. ' It is important that the lowest points of the steam .mains and heating units be kept sufficiently above the water line of the boiler to prevent flooding. Usually 18 in. is sufficient but construction limitations fre quently make shorter distances necessary. The distance may be checked in the following manner: - ' Referring to Fig. 4 it will be seen that the water in the wet return is really in an in verted siphon, or U-shaped container,'with the boiler steam pressure on the top of the 535 ./ of and 1936American Society Heating Ventilating Engineers Guide, water at one end and the steam main pressure on the top of the water at the other end. The difference between these two pressures is the pressure drop in the system, i.e., the friction of the steam in passing from the boiler to the far end of the main. The water in the far end will rise sufficiently to overcome this difference in order to balance the pres sures, and it will rise enough farther to produce a flow through the return into the boiler Steam pressure at Fig. 4. Difference in Steam Pressure on Water in Boiler and at End of Steam Main (usually about 3 in. unless the pipes are small or full of sediment), and it will rise still farther if a check valve is installed in-the return so as to obtain sufficient head to lift the tongue of the check (usually 4 in. will be necessary). If a one-pipe steam system is designed, for example, for a total pressure drop of lb, and utilizes an Underwriters Loop* instead of a check valve on the return, the rise in the water level at the far end of the return due to the difference in steam pressure would be % of 28 in., or 3H in- Adding 3 in. to this for the flow through the return main and 6 in. as a factor of safety gives 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 H lb, and with a check in the return, would require Vi of 28 in., or 14 in., for the difference in steam pressure, 3 in. for *See discussion of.piping details in Chapter 32. 536 31--Chapter Steam Heating Systems 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. Down-Feed Gravity One-Pipe Air-Vent System In the overhead down-feed gravity one-pipe air-vent system there is no change over the up-feed, system in the radiators, the radiator valves, the air valves, or the radiator runouts as far back as the risers. Beyond this point there are basic differences. The steam is taken from the boiler and carried to the top of the building as near the boiler as possible (Fig. 5). If the run to the main riser is long, or if the riser extends several stories in ' order to reach the top, the bottom of the riser should be dripped into the wet return. The horizontal main is taken off the top of the riser and ' grades down from the riser toward all of the drops, each drop taking its share of the main condensation (Fig. 6), or all of the drops except the last , may be taken from the top of the main (Fig. 7), the last drop being from the bottom and serving as a drain for the entire main. As the overhead Runouts Steam drop to radiators Fig. 6. Steam Runouts Dripping Main Steam drop to radiators' Fig. 7. Steam Runouts with Main Dripped at End Only main does not carry any condensation from the radiators it is immaterial which method is used. The air vent shown on the main just before the last drop (Fig. 5) may be placed at this point or it may be located at the bottom of the drop under the last radiator connection and sufficiently above the water line of the boiler to prevent flooding. GRAVITY TWO-PIPE AIR-VENT SYSTEM The gravity two-pipe system is now considered obsolete although many of these systems are still in use in older buildings. Separate supply and return mains and connections are required for each heating unit; air valves are installed on the heating units and mains; hand valves are installed on the returns. . . Up-Feed Gravity Two-Pipe System This system (Fig. 8) has a steam and a return connection to each radiator. The radiator valves for steam, return, and air are the same as those described for the gravity one-pipe air-vent system. The steam main is run and pitched in the same manner as in the one-pipe system, but the returns from each radiator are connected into a separate return line system which has its risers carried down, and joined to a wet return line under the boiler water line level. Where the return has to be kept high to function as a dry return, it is advisable to connect the return 537 of and 1936American Society Heating Ventilating Engineers Guide, 31Chapter --Steam Heating Systems risers to the dry return main through-water seals about :36 in. deep, as shown in Fig. 9, to prevent steam from one riser entering another and closing the air valves on the nearest radiators. Down-Feed Gravity' Two-Pipe System The steam main in the down-feed system is carried to the top of the building, and the piping of the steam side is arranged practically as in the down-feed one-pipe gravity system. The drips at the bottoms of the steam drops and the runouts to the radiators are similar to those shown in Fig. 8 for the up-feed gravity two-pipe^system. On the return side of the system, the piping is arranged in exactly the same manner as the up-feed gravity two-pipe system. . ONE-PIPE VAPOR SYSTEM A vapor system is one which operates under pressures at or near atmospheric and which returns the condensation to the boiler by gravity. The piping arrangement of a one-pipe vapor system is similar to that of the gravity one-pipe steam system; in fact, one-pipe gravity installations may readily be changed to one-pipe vapor systems by making a few simple alterations. The steam radiator valve is a plug cock which when opened gives a free and unobstructed passageway for water. The auto matic air valve is of special design to permit the ready release of air from the radiator and to prevent the return of the air after it is expelled. The air valves on the main are a quick relief type, and the whole system is designed to operate on a few ounces of pressure. 538 Cleanout Fig. 9. Method of Connecting Two-Pipe Gravity Returns to Dry Return Main y-Floer '7777777777777777777 TWO-PEPE VAPOR SYSTEM Two-pipe vapor systems may be classified as (1) closed systems con sisting of those which have a device to prevent the return of air after it is once expelled from the system, and which can operate at sub-atmospheric . pressures for a period of four to eight hours depending upon the tightness of the system and rate of firing, and (2) open systems consisting of those which have the return line constantly open to the atmosphere without a check or other device to prevent the return of air, and which operate at a few ounces above atmospheric pressure. The open systems have the disadvantage of not holding heat when the rate of steam generation is diminishing. . Under the first classification the essentials are packless graduated Fig. 10. Typical Up-Feed Vapor System with Automatic Return Trap3 "Proper piping connections are essential with special appliances for pressure equalizing and air elimination. 539 American Society of Heating and Ventilating Engineers Guide, 1936 valves on the radiators, thermostatic return traps on the returns, and' traps on all drips unless they are water sealed. Such a system, illustrated in Fig. 10, should be equipped with an automatic return trap to prevent the water from backing out of the boiler. In this up-feed arrangement the supply piping is carried to a high point directly at the boiler and is graded down toward the end or ends of the supply main, each supply main being dripped at the end into the wet return or carried back to a point near the boiler where it drops down below the boiler water line and becomes a wet return. From this main, runouts are branched off to feed risers or radiators above, these being graded back toward the steam main Air vent and check Fig. 11. Typical Connections for Automatic Return Trap ^ if they are not dripped at the bottom o{ the riser, or toward the riser if the riser heel is dripped. Both conditions are illustrated in Figs. 2 and 3. Return risers are connected to each radiator oh its return end through thermostatic traps. Their bottoms are connected to the return main through runouts which slope toward the main.- The return main itself is sloped back toward the boiler if it is carried overhead; if run wet, the slope may be neglected, although it is desirable to slope the pipe so that the system may be drained. An air vent is installed at- the point at which the return main drops below the water line. In the simplest cases this vent consists of a %-in. pipe with a check valve opening outward, but certain systems employ special patented, forms of vent valves,' designed to allow the air readily to pass out of the system and to prevent its return. A check valve is inserted in the return main at a point near the boiler and a vertical pipe is run up into the bottom of the return trap, which usually 540 Chapter 31--Steam Heating Systems is located with the bottom about 18 in. above the boiler water line. Some traps are constructed so that they will operate when they are installed with their bottom as close as 8 in. above the boiler water line. On the other-side of this connection a second check valve is installed in the main return just before it enters the boiler (Fig. 11). Down-Feed Two-Pipe Vapor System In the down-feed two-pipe vapor system the steam is carried to the top . of the building, the top of the vertical riser constituting the high point of the system, and the horizontal supply main is sloped down from this location to the far ends of each branch. The branches are taken off the main from the bottom or at a 45-deg angle downward, with the runouts Bottom of steam droD~~* Graduated valve Drip c Drip trap Dirt pocket- J^FIoor '//////////a ^Connected to dry return (where connected to wet return, drip trap may be omitted) Fig. 12. Detail of Drip Connections at Bottom of Down-Feed Steam Drop sloped toward the drops (Fig. 6). Thus each branch from the main forms a drip and no accumulation of water is carried down any one drop. Another method of running the steam main, which is not considered as satisfactory but which is practical, is to take the branches off the top of the main (Fig. 7) and to drip the end of the main through; the last riser, as illustrated in the down-feed one-pipe system detail shown in Fig. 6. If this is done, the pipe drop at the end or ends of the mains should be enlarged one pipe size to provide capacity for this concentration of the main drip. The steam drops are carried down through the building with suitable reductions as the various radiator connections are taken off until the lowest radiator runout is reached. If the drop is only two or three stories high, the portion feeding the bottom radiator should be increased one pipe size to provide for draining the riser, and if the drop is over three stories high it is well to increase the portion feeding the two lowest radi ators one or two pipe sizes, especially if the two lowest radiators arc small and the normal size of drop required is 1 in. or less. The bottom of the steam drops should terminate with a dirt pocket above which a drip trap . 541 American Society of Heating and Ventilating Engineers Guide, 1936 Fig. 13. Typical Atmospheric System with Automatic Return Trap Proper piping connections are essential with special appliances for pressure equalising and air elimination ' Chapter 31--Steam Heating Systems connection is located, as shown in Fig. 12. The returns on a down-feed vapor system are the same as on an up-feed system except that every steam drop must have a drip at the bottom connected either into the return through a trap or into a separate water-sealed drip line below the boiler water line, as illustrated in Fig. 10, in which case the thermostatic traps may be omitted. The runouts to the radiators and the radiator connections of the down-feed system are the same as those of the up-feed system already described. , ATMOSPHERIC SYSTEM The distinguishing features of the atmospheric system are gravity return to the boiler or to waste, graduated or ordinary radiator valves, no '..automatic air valves on the radiators, thermostatic traps on the radiator 'returns, and the venting of all air from the system by means of pipes open to the atmosphere. The returns are open to the atmosphere at all times, usually by extending the return risers to the top of the building where they are either connected together in groups and carried through the roof or extended through the roof individually. Atmospheric systems, either up-feed or down-feed, are often used where the condensation is not returned to the boiler, as in heating systems supplied by high pressure steam through pressure-reducing valves at locations far from the boilers. The returns may be delivered back to the boiler, if desired, by condensa tion return pumps which are vented to the atmosphere. The return lines in such systems are simply gravity waste lines in which the condensation flows entirely by gravity, and is not aided by any pressure difference. Atmospheric systems contemplate maintaining a practically constant pressure in the steam pipe and atmospheric pressure in the return pipe. When graduated steam valves are provided, they enable the occupant of a room to vary the flow area to the radiator so as to obtain a greater or lesser heating effect. The steam side may be run as that for either up-feed or down-feed two-pipe vapor systems, as the conditions require, and the radiator con nections are the same as for vapor systems in that they have graduated valves on the radiator supply ends and thermostatic traps on the radiator return ends.. All drips from the supply main and the steam side of the system must pass through thermostatic drip traps before entering the return system where only atmospheric pressure exists. . Fig. 13 illustrates a typical scheme of piping used on atmospheric systems. VACUUM SYSTEM In the vacuum system, a vacuum is maintained in the return line practically at all limes but no vacuum is carried on the steam side, and the usual accessories include graduated valves on the radiator supply and thermostatic traps on the radiator return. The air is expelled from the system by a vacuum pump and all drips must pass through thermostatic traps before connecting to the return side of the system. These systems are often fed from high pressure steam mains through pressure-reducing valves but they may be fed direct from a low-pressure steam heating boiler as shown in Fig. 14, in which a typical up-feed 543 American Society of Heating and Ventilating Engineers Guide, 1936 vacuum system is illustrated. The supply main slopes down in the direction of flow; the runouts pitch down toward the riser if the riser is dripped (Fig. 3) or up toward the riser if the riser is not dripped (Fig. 2); both conditions are indicated in Fig. 14. The matter of dripping the risers depends largely on the height of the riser and the judgment of the designer. Ordinarily risers less than three stories high are not dripped and those more than four stories high are dripped, but there is no set rule for this. When risers are dripped the runouts from the steam main may be taken from the bottom if desired and each runout then serves as a drip for the main. The risers are carried up to the highest radiator connection and are connected to the radiator through runouts sloping back toward the riser. The radiators usually have graduated valves on the supply end, although this is not absolutely necessary. Angle-globe valves and gate valves may be used where graduated manual control is not desirable. The return valves must be of the thermostatic type which will pass air and water but which will close against the passage of steam. The return risers are connected in the basement into a common return line, which slopes downward toward the vacuum pump. The vacuum pump discharges the air from the system and pumps the water back to the boiler, or other receiver, which may be a feed-water tank or a hot well. It is essential on these systems that no connection from the supply side to the return side be made at any point except through a trap. While the best practice demands a return flowing to the vacuum pump in an uninterrupted downward slope, in some cases limitations make it necessary to drop the return below the level of the vacuum pump inlet before the pump can be reached. In such event one of the advantages of the vacuum system is that the return can be raised by the suction of the vacuum pump to a considerable height, depending on the amount of vacuum maintained, by means of a lift fitting inserted in the return. . Best practice dictates that the lift should be limited to a single lift con nection at the entrance to the vacuum pump and that lifts scattered throughout the system be avoided. When the lift is considerable, several lift fittings are used in steps (Fig. 15), more successful operation being obtained by this method than when the lift is made in one step. If the lift occurs close to the vacuum pump, a special arrangement is used as shown in Fig. 16. It is desirable that means be provided for draining manually the low points of the lift fittings to eliminate from the return piping all water in danger of freezing in case the system is shut down for a considerable length of time. Down-Feed Vacuum System ' The piping arrangement for the down-feed vacuum system is similar on the supply side to the down-feed vapor system in that it has similar runouts, radiator valves, drips on the bottom of the steam drops, and enlargement of the drops for the lower radiator connections. The return side of the system is exactly the same as the up-feed system except that the steam riser drips at the bottom are connected into the return line through thermostatic traps. It is preferable to take the runouts for the risers from the bottom or at a 45-deg angle down from the steam main (Fig. 6) so that they may serve as steam main drips. When this is.done 544 Chapter 31--Steam Heating Systems it is practical to run the steajn main level if a runout is located at every change in pipe size,, or if eccentric fittings are used (Fig. 17). A slight pitch in the steam main, however, should be used when, possible. An overhead vacuum down-feed system is shown diagrammatically in Fig. 18. SUB-ATMOSPHERIC SYSTEMS Sub-atmospheric systems are similar to vacuum systems, but in con trast provide temperature control by variation of the heat output from the radiators both by varying the pressure at which steam is circulated in the radiation and the amount of steam. The steam supply is continuous Fig. 15. Method of Making Li?ts on Vacuum Systems when Distance is Over 5 ft Fig. 16. Detail of Main Return Lift at Vacuum Pump PB I EeCcCcEeNnTtKrHic reducing ( COUPLING. 17.Fig. 'Method of Changing Size of Steam Main when Runouts are Taken from Top ' at varying rates. A vacuum pump capable of operating at high partial vacua is preferable since the higher the vacuum the greater is the accuracy in the distribution of steam through the system, particularly in mild weather. A. pump capable of producing up to 25 in. of vacuum on the system is used in such cases. A controller is placed on the pump so that the vacuum or absolute pressure carried in the returns can be maintained at a certain amount below that existing in the line to insure circulation. The traps are designed to operate in high vacuum. It is apparent that this system differs from the ordinary vacuum system by having a vacuum on both sides of the system, instead of only on the return side, in order to secure control of the heat emission from the radiators and thus to control the temperature in the building. These systems permit the heat output from the steam mains and risers to be diminished as the weather becomes milder, thus giving control to this portion of a heating system. The system can be operated in the samd manner as the ordinary vacuum system when desired. . ....... "1 American Society of Heating and Ventilating Engineers Guide, 1936 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-atmospheric system, steam pressure exists in the steam main and radiators only during the most severe weather, while under average winter temperatures the steam is under a partial vacuum which in mild weather may reach as high as 25 in. after which further reduction in heat output is obtained by partially filling the radiation with steam. This vacuum is partially Self-induced by the condensation of the steam in the system due to the supply of steam being furnished through the ' control which admits it, and it being proportioned to balance the existing heat loss. In the sub-atmospheric system, a control valve is inserted on the steam main of an ordinary, vacuum' system, near the boiler or the boiler is automatically controlled, a high-vacuum pump is substituted for the ordinary type and is supplied with-a-pressure+lifference control, and traps are placed on the radiators and drips which will operate satis factorily. at any pressure from 5 lb gage to 26 in. of vacuum. . . . The control valve is either a special pressure-reducing valve which .may be controlled manually, or a control: valve or combustion equipment which-may be operated' thermostatically , from points selected in the building. The vacuum pump-regulator is simply a diaphragm so ar ranged that, when the vacuum in the return line is insufficient to hold the desired difference in pressure between the steam and return sides of the system, the vacuum pump is automatically started and the vacuum increased to the necessary amount. The actual pressure difference main- 546 Chapter 31--SteaiT Heating Systems tained between the two sides of the system is only enough to secure adequate circulation and is often about 2 in. of mercury. This fixed pressure difference between the supply and return sides of the system I- results in practically constant circulation under all pressure conditions. In order to distribute the steam equally when the system is being warmed up and also to reduce the amount of steam delivered to the radiators on mild days, orifice plates are used in the graduated radiator control valves. The heat emitted from the radiators in mild weather and under conditions of high vacuum is not only reduced in proportion to the difference in the steam temperature between that for 2 lb gage and for 25 in. of vacuum but it is reduced still further by a reduction in the amount of steam which can pass through the orifice when the steam is expanded . due to the vacuum. This renders possible the control of' heat emission from the radiators to a point not indicated entirely by the difference in steam temperatures, but far beyond it. ' '. Sub-atmospheric operation has advantages even where individual thermostatic radiator control is installed. By operating the system with --- . steam temperatures in parallel with the outside temperature require . mentis, a large part of the load is removed from the temperature control system, it makes fewer operations and the radiator follows an even tem perature without fluctuating from extreme hot to extreme cold. .. . The high-vacuum pumps on this system are equipped with receivers having float control so that the pump can be placed on a receiver-retumpump basis at night if desired so no high vacuum will be carried. One radical difference between this system and the ordinary vacuum system is that no lifts can be made in the return line, except at the vacuum pump. The returns must grade downward constantly and uninterruptedly from the radiator return outlet to the inlet on the high-vacuum pump receiver. No attempt should be made to heat service water on this system unless the steam line for water heating is taken off the boiler header back of the heating system control valve, and then only when 2 lb or more will be carried on the boiler at all times. , . , ORIFICE SYSTEM Orifice systems of steam heating may have piping arrangements identical with vacuum systems but some of these systems omit.both the radiator thermostatic traps and the vacuum pump in cases where the returns are wasted to a sewer or delivered to some type of receiver in which no back pressure exists. The principle on which they operate is embodied in the well-known fact that an orifice will deliver varying velocities when the ratio of the absolute pressures on the two sides of the orifice exceeds 58 per cent. If the absolute pressure on the outlet side is less than 58 per cent of the absolute pressure on the inlet side no further increase in velocity will be obtained. As a result, if an orifice is so designed in size as to exactly fill a radiator with steam at 2-lb gage on one side and 34-1 b gage on the other, the abso lute pressure relation is 14.7 + 0.25 14.7+ 2.0 90 per cent 547 '/ American Society of Heating and Ventilating Engineers Guide, 1936 Should the steam pressure be dropped to J4-lb gage, the pressure on each side of the orifice would be balanced and no steam flow would take place. From this it will be seen that if an orifice of a given diameter will fill a given radiator with steam when there is a given pressure on the main, it is simply a question of dropping this main pressure provided the supply pipe pressures be .controlled sufficiently closely, so as to fill any desired portion of the radiator down to the point where the main pressure equals the back pressure in the radiator, at which time no steam will be supplied at all. If orifices throughout a system are designed on a similar basis, all radiators will heat proportionately to the steam pressure within the limits for which the orifices are designed. Some systems use orifices not only in radiator inlets but also at different points on the main, thus balancing the system to a greater extent. For example, the system may be designed for a particularly long run involving an initial pressure of 3-lb gage on the main and 2 lb at the end of the main, but each branch from the main may have an orifice for reducing the pressure at it to 2 lb-gage. This is particularly useful for branches near the boiler where the drop in the main has not yet been produced. Orifice systems using a vacuum pump operate successfully with the ordinary low vacuum type of pump producing 8 to 10 in. of vacuum. They are controlled by various means to regulate the steam pressure. One method is by a thermostat located on the roof to govern the steam pressure by a combination of outside and inside temperatures; another, useful on systems without traps and vacuum pumps, controls the steam pressure manually from temperature indication stations in the building, or automatically by a thermostatically-controlled pressure reduction valve or draft regulator on the boiler; with oil or gas firing, the on-and-off control or a boiler pressure control may be used. ZONE CONTROL ' Certain portions of a building may require more heat at times than others but if the whole building is on one general control, such as would occur with a single piping system with an on-and-off control or with the sub-atmospheric or the orifice systems, it would be necessary to supply sufficient heat to accommodate the coldest portion of the building even though some sections would be overheated. By separation of a building into zones each with its own piping system, each zone of the building may be controlled separately. x -. The sides of the building with different exposures should be considered first, because of the varying effects of the wind and sun. With the pre vailing winter winds from the northwest; a simple zoning would place the north and west sides of the building on one system and the south and east sides on another. If the building is large enqugh to justify the expendi ture, a better arrangement would be to place all north walls on one zone, all west walls on a second, all east walls on a third, and all south walls on a fourth. In case of high buildings, the lowest 8 or 10 stories.may be well protected from wind by surrounding buildings, the next 10 stories may have moderate exposure, and above this there may be an unobstructed exposure to gales. On still days the heat demands vertically will vary little, but on 548 Chapter 31--Steam Heating Systems windy days there will be a marked difference in the heat requirements for the different horizontal sections. In addition, the chimney effect caused by the difference in density between the warm air on the inside of a building and the colder air on the outside will give an-air movement which will require zoning to correct. Where such conditions are encountered, the building should be divided horizontally as well as vertically. An arrangement of this character would give 12 zones: namely, north, east, south, and west lower zones; similar middle zones; and similar top zones. Each zone should constitute an individual and separate system of piping with its own supply steam valve (controlled by thermostats in its respec. tive zone) and with its own return or vacuum pump, if one is used. Certain interior areas, such as basements, light well walls and other locations where sun and wind do not affect the conditions, should be placed in still another zone if the most economical results are to be secured. Zoning has advantages even where individual thermostatic radiator control is installed whether this be of pneumatic, electric, or the selfcontained radiator valve type. By operating each zone to supply heat in parallel with its outside temperature and wind fluctuations, a large part of the load is taken off the thermostatic controls; they operate less frequently and the radiators follow a more even temperature instead of fluctuating from extreme hot to extreme cold. Sub-atmospheric, orifice, and zone control systems, generally are proprietary. - CONDENSATION RETURN PUMPS Condensation return pumps are generally required when the elevation of the boiler with respect to the heating units is such that the condensate will not return by gravity, or when the boiler pressure is greater than that supplied the heating units, as in a high-pressure boiler installation sup plying steam through a reducing valve to the heating units. The con densate is commonly returned by gravity to a receiver, vented to the atmosphere, from which it flows to the pump. Condensation return pumps are assembled with tank or receiver and arranged for either continuous operation or for automatic starting and stopping by float control. Any style of water pump may be employed for this service, the power available determining whether the mode of drive shall be steam or electric. The motor-driven, automatic, centrifugal, pump and receiver has found wide acceptance for low pressure heating systems. . Fig. 19 shows a typical installation using an automatic condensation return pump and vented receiver. A float control operates the pump whenever sufficient water accumulates in the receiver. Condensation return pumps are suitable for use on systems in which the returns are under atmospheric pressure. These include atmospheric systems, orifice systems with open returns, and certain types of vapor systems whichoperate within a few ounces of atmospheric pressure, but ordinarily do not carry any sub-atmospheric pressure. They may also be. used on one-pipe and two-pipe gravity steam systems with a proper arrangement for venting the receiver. In discharging to waste, there is no object in using a condensation pump unless the discharge must be elevated. 549 American Society of Heating and Ventilating Engineers Guide, 1936 VACUUM PUMPS A vacuum heating pump is employed to create a vacuum on the return side of a system to remove air and water from the return piping and to pump the condensate to the boiler or to a receiving tank. Pumps of this classification may be driven by steam or electricity; they may be continuous in operation, or automatic with float or vacuum control in one or more combinations. ' For rating purposes3, vacuum pumps are classified as low vacuum and high vacuum. Low vacuum pumps are those rated under operation at 5Hj-in. mercury vacuum, and high vacuum pumps are those rated at. vacuums above 53^ in. Fig. 19. Typical Installation Using 'Condensation Pump Return line vacuum, pumps are classified in the method of their per formance as follows: ' a. Those which perform the function of air separation under' atmospheric pressure. b. Those which perform the function of air separation under a partial vacuum. Pumps coming under the first classification will handle vacuum steam system condensation coming back by gravity at any temperature up to 205 F without either the sealing or the hurling water flashing into steam. These pumps, to operate under a combined water level and vacuum con trol; must be equipped with a float-control receiver between the vacuum pump and the system, but where they are intended for continuous opera tion, they do not require a receiver. Such pumps employ a single vacuum 3See A.S.H.V.E. Standard Code for Testing and Rating return line low vacuum heating pump. 550 Chapter 31--Steam Heating Systems producer which removes the condensate and air from the system and delivers it into a separating chamber under atmospheric pressure from which the condensate is delivered to the boiler or feed water heater. They are constructed on one of the following evacuating and discharge principles: 1. Hydraulic vacuum producer with one pump impeller. 2. Hydraulic vacuum producer with two pump impellers. 3. Water displacement vacuum producer with two pump impellers. 4. Piston displacement vacuum producer with one pump piston. . The second classification of pumps will handle vacuum steam system condensation coming back by gravity at any temperature not exceeding 190 F without the flashing into steam of either the sealing or the hurling water. In order to operate under a combined water-level and vacuum control, these pumps must be equipped with a float-control receiver between the vacuum pump and the system; where intended for con , tinuous operation they do not require a receiver. Such pumps employ a vacuum producing impeller which removes air from the receiver or heating system under a partial vacuum and delivers it through an air separator against atmospheric pressure. The condensate is removed from the receiver under a partial vacuum by a separate impeller and is delivered to the boiler or feed water heater. For evacuating and dis charge, a water displacement vacuum producer with two pump impellers is used. . Receiver Capacities for Vacuum Pumps Where receivers are used in connection with vacuum pumps there: is a definite relation between the capacity of. the receiver and the capacity of the pump. The receiver should have a capacity of not less .than V/z times the volumetric quantity of condensation per minute and should not have such a capacity that the pump will empty the receiver in less than half a minute. Receivers of larger capacities will'result in less frequent periods of operation. , Piston pisplacement Vacuum Pumps , .... ....,. Pistoii displacement return-line vacuum heatirig;pumps may be either power or steam driven. They should be provided with mechanical lubricators and. their piston speed in feet per minute should not exceed 20 times the square root of the number of inches in their stroke. While the volumetric displacement for such pumps was formerly figured at 8 to 10 times the volumetric flow of condensation to .be handled, the., more efficient..thermostatic.'traps used today-in connection with vacuum heating system's make it possible to change this proportion so that the. volumetric displacement of these pumps may not be less than 6 times the volume of condensation: - -. . . ' i ;'' Vacuum Pump Controls ... ' '.' .'; In' the ordinary vacuum: system the vacuum pump is controlled by1 a vacuum regulator which cuts in when the vacuum drops to the iowest point desjrec}.and which cuts out when the Vacuum has been .inctea^e^ to the highest.point.' .This is done largely to eliminate the constant' starting and stopping of the vacuum pump which would occur if the vacuum were 551 American Society of Heating and Ventilating Engineers Guide, 1936 maintained constant. In addition to this control, a float control is in cluded which will automatically start the pump whenever sufficient con densation accumulates in the receiver, regardless of the vacuum in the system. This arrangement makes the vacuum pump primarily a con densation pump and secondarily an air pump. On the sub-atmospheric systems the high vacuum pump is controlled by a differential regulator which keeps the vacuum in the return line always a few inches higher than that in the steam line and in the radiators. TRAPS Traps are used for draining the condensate from radiators, steam piping systems, kitchen equipment, laundry equipment, hospital equip ment, drying equipment and many other kinds of apparatus. The usual functions of a trap are to allow the passage of condensate and to prevent the passage of steam. In addition to these functions, traps are frequently required to allow the passage of air as well as condensate. Traps are also required to allow the passage of air and to prevent the passage of either water or steam, or both. In addition, traps are used for returning condensate either by gravity, by steam pressure, or by both, to a boiler or other point of disposal, and for lifting condensate from a lower to a higher elevation, or for handling, condensate from a lower to a higher pressure. The fundamental principle upon which the operation of practically all traps depends is that the pressure within the trap at the time of discharge shall be equal to, or slightly in excess of, the pressure against which the trap must discharge, including the friction head, velocity head and static head on the discharge side of the trap. If the static head is in favor of the trap discharge it is a minus quantity and may be deducted from the other factors of the discharge head. ' - Traps may be classified according to the principle of operation as (1) float, (2) bucket, (3) thermostatic, or (4) tilting traps. Float Traps. A discharge valve is operated by the rise and fall of a float due to the change of water level in the trap. When the trap is empty the float is in its lowest position, and the discharge valve is closed. A gage glass indicates the height of water in the 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. The discharge from a float trap is usually con tinuous since the height of the float, and consequently the area of the outlet, is propor tional to the amount of water present. Bucket Traps. Bucket traps are of two types, the upright and inverted, and although they are both of the open float construction, their operating principle is entirely different. In the upright bucket trap, the water of condensation enters the trap 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 water rises above the edges of the bucket it flows into it and causes it to sink, thereby withdrawing the valve from its seat. This permits the steam pressure acting on the surface of the water in the bucket to force the water to a 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. In the inverted bucket trap, steam floats the inverted submerged bucket and closes the valve. Water entering the trap fills the bucket which sinks and through compound leverage opens the valve, and the trap discharges. It is impossible to install a water 552 Chapter 31--SteAm Heating Systems gage glass on an; inverted bucket trap, but if visual inspection is necessary, a gage glass can be placed on the line leading to the trap. No air relief cocks can be used, but this is unnecessary, as the elimination of air is automatically taken care of by air passing through the vent in the top of the inverted bucket regardless of temperature. ' Thermostatic Traps. Thermostatic traps are of two types, those in which the discharge valve is Operated by the relative expansion of metals, and those in which the action of a volatile liquid is utilized for this purpose. Thermostatic traps of large capacity for draining blast coils or very large radiators are called blast traps. . Tilting Traps. With this type of trap, water enters a bowl and rises until its weight overbalances that of a counter-weight, and the bowl sinks to the bottom. As the bowl sinks, a valve is opened thus admitting live steam pressure on the surface of the water and the trap then discharges. After the water is discharged, the counter-weight sinks and raises the bowl, which in turn closes the valve and-the cycle begins again. Tilting traps are necessarily intermittent in operation. They are not ordinarily equipped with glass water gages, as the action of the trap shows when it is filling or emptying. The air relief of tilting traps is taken care of by the valves of the trap. Thermostatic traps are generally used for draining radiators and heaters, except for very large capacities where bucket, float or blast-type Fig. 20. Method of Discharging High-Pressure Apparatus into Low-Pressure Heating Mains and Vacuum Return Mains through a Low-Pressure Trap thermostatic traps are used. Thermostatic trapis for this service usually pass both condensate and air and in the case of float and upright bucket traps the air is usually relieved through an auxiliary thermostatic trap in a by-pass around the main trap. Sometimes this auxiliary air trap is an integral part of the trap. Such traps are termed float and thermostatic traps. . Blast-type thermostatic traps are sometimes used on vacuum heating systems for connecting old one- or two-pipe gravity systems in parallel with vacuum return line systems, in which,,case the blast-type thermo static traps should not be provided with auxiliary air by-pass, as the action of this will allow the vacuum to draw air into the old system through its air valves, especially when the steam is wholly or partially cut off. The air from the returns of such old systems should be relieved just ahead of the traps by means of quick-venting automatic air valves, preferably of the non-return type, especially if the other air vaives: on the old system are non-return valves. ;, : Tilting traps used for discharging to a higher or a lower pressure are 553 American Society of Heating and Ventilating Engineers Guide, 1936 provided with two or three valves operated by the action of the trap. In the case of the two-valve tilting traps, one valve closes a steam inlet and the other valve opens a vent outlet while the trap is tilling, and as soon as the trap dumps, the first valve opens the steam inlet and the String Check Vahe f77tzrmo$faiic Air Valve Returns-... jvf J Check Vatox Ttt\ --=^r'SaMy /a/ve Gage. Glen Connection for Test-Gage 'Strainer f^Stand Pipe &' Fig. 21. Return Trap, and Receiver for Automatic Boiler Feed second valve closes the vent-outlet, while1 the trap discharges. In this type of trap there must be a swinging- check-valve on each side of the trap, in addition to the usual by-pass, to.prevent the pressure in the trap, while discharging, from backing up through the- inlet and the pressure in the discharge line.from backing up into the trap while it is filling. This 654 Chapter 31--Steam Heating Systems type of trap will blow steam out through the vent while filling, if the pressure on the inlet side is sufficient, and should not be used, therefore, with such pressures unless the vent is properly piped back into the return - to a feed water heater, a condenser or a perforated pipe in the bottom of the receiver to which the trap discharges in such a way as to prevent the escape of the steam that comes in with the condensate and passes through the vent. In the three-valve traps of this type there is an extra valve for closing the discharge while the trap is filling. High pressure traps should not discharge directly into a vacuum return because of the vapor formed by the re-evaporation of a part of the hot condensation. Fig. 20 shows a method which may be used for disposing of the greater part of the vapor of re-evaporation. An expansion chamber often is installed between the high- and low-pressure traps. .Automatic Return Traps In the general heating plant, where thermostatic traps are installed on the heating units, it becomes necessary to provide a means for returning ' the wafer of condensation to the boiler, if a condensation or vacuum pump is not used. When the return main can be kept sufficiently high above the . boiler water line for all operating conditions, the water of condensation will flow back by gravity, and no mechanical device is required. But actually this does not work out in practice. It follows, therefore, that a direct return trap is needed for the handling of the condensation even though it may not be called into action except under some operating condition where the pressure differential exceeds the static head provided. The installation of a direct return trap assures safety for such systems, and guarantees the operation of the plant under varying conditions. Automatic return traps, sometimes called alternating receivers, may be of the counterbalanced, tilting type, or spring actuated. These consist of a small receiver with an internal float, and when the condensate will not flow into the boiler under pressure, it will feed into the receiver of the trap, and in so doing, raise or tilt the float or mechanism which actuates a steam valve automatically. This admits steam to the receiver, at boiler, pressure, and the equalizing of the pressures which follows allows the water to flow into the boiler. Fig'. 21 shows a direct return tilting trap and receiver properly connected for automatically feeding a boiler from a system of returns delivering the condensate to the receiver. PROBLEMS Ii\ PRACTICE 1 What is meant by water line difference in a gravity steam heating system? The water line difference is the distance between the level of the water in the dry or wet return and the boiler water line. This difference is equivalent to the pressure required to overcome the maximum drop in the system, and the operating pressure of the boiler. ^ How many types of common mechanical returns are there and what are they? ... - Three: (1) the mechanical return trap, (2) the condensation return pump, and (3) the vacuum pump. 655 s American Society of Heating and Ventilating Engineers Guide, 1936 3 Iti the ordinary vacuum system1 of steam heating, where does1 the vacuum usually exist? . . ,: : On the .return side of the system only, between the radiator trap and the vacuum pump. If the radiator supply valve is closed off, the vacuum may extend, back through the radiator as far as the supply valve; if an adequate supply of steam is furnished to the system, some vacuum may be developed in the steam main, but neither of these can be termed notmai Operation: . : .. : . 4 What is the distinction between the open and the closed vapor systems? The open vapor system has the return line always Open to the atmosphere, while the closed vapor system has an automatic device, on the air vent .so that air once expelled froiti the system through the vent cannot re-enter via this route. - 5 On a vacuum system, what device must be placed on all drips before they enter the vacuum return line? A thermostatic drip trap or occasionally, where large volumes of condensation are to be handled, a float trap. ' 6 How does the sub-atmospheric system differ in operation from the ordinary vacuum system? , ', The ordinary vacuum system has pressure in the steam line, and a vacuum produced by the vacuum pump in the return line, usually varying between 5 and 10 in. of water. The sub-atmospheric system may have either a vacuum or pressure on the. steam and return lines, but a constant difference in pressure is maintained between the iines regardless of what pressure or vacuum may be carried. The vacuum, which is generally produced by condensation in the system under conditions of throttled steam supply, may run much higher than in the ordinary vacuum systems. 1 7 What is generally understood by zoning in building steam heating systems? Zoning is a term applied to the placing of certain sections of a building on a single temperature control instead of having either individual room control or a single tempera ture control governing the whole building.. Zones may be horizontal, such as a single story, a basement, or an attic, or. vertical such as the north side, or the west side. . 8 Why does the water line in the far end of a wet return in a gravity steam system rise higher than the water line in:the boiler? The friction of the steam flowing through the steam main from the boiler to the far end of the system causes a drop in steam pressure at the point where the wet return is connected; consequently, the steam pressure on,top of. the water in the wet return is less than the steam pressure on top of the water in the boiler, so the water in the end of the wet return rises until a balanced condition is set up. . .. 9 # On gravity one-pipe systems as indicated in Fig. 1 and Fig. 3, why is the drip on the steam runout'connected to Wet return? Because if it were Connected to dry return, the pressure drops to two different points would not necessarily be the same,and the system would short circuit. 10 t What is the function of the automatic return trap? To insure the return of condensate to the boiler when the operating condition is such that the boiler pressure exceeds the static head on the returns. 11 What advantage is there to an air valve with a check to prevent the re entrance of expelled air? A system equipped with such valves builds up a vacuum and holds the heat longer. With proper controls on the boiler, lower radiator temperatures can be' maintained in mild weather, giving better plant efficiency. '' 1 556 Chapter 32 PIPING FOR STEAM HEATING SYSTEMS Flow of Steam in Pipes, Pipe Sizes, Tablesfor Pipe Sizing, Sizing One-Pipe Gravity Air Vent Systems, Two-Pipe Gravity Air Vent . Systems, Two-Pipe Vapor Systems, Atmospheric Systems, Vacuum Systems, Sub-Atmospheric Systems, Orifice Systems, - High Pressure Steam, Expansion in Steam and Return lines, Piping Connections and Details, Boiler Connections, Hartford Return Connection THE design of a steam heating system should be considered under four headings, namely, (1) the details of the heating units, (2) the arrange ment of the general piping scheme, (3), the details of connections, and (4) the sizing of the lines. Items 1 and 2 are covered in Chapters 30 and 31, respectively, while this chapter considers the two latter items. The functions of piping are to supply the heating units with steam and to remove the condensation. In some systems both the air and con densation are removed from the heating units by the return piping. To accomplish this effectively, the distribution of the steam should be efficient and equitable, without noise, and the returns should.be as-.short as possible. When air is handled its escape should be facilitated to the utmost since an air-bound system will not heat properly. _ Condensation takes place in a steam system not only in the heating units, but through out the piping system as well, and the returns also condense any steam or vapor that may be contained. At the same time part of the condensation may flash back into steam when the vacuum or pressure in the return is considerably below the steam pressure. It is essential that steam piping systems not only distribute steam at full load but also at partial loads, as the average winter demand is less than half of the demand in most severe outside temperatures. Further more, in heating up rapidly the load on the steam main may exceed the maximum operating, load even in extreme weather, due to the necessity of raising the temperature of the metal in the system to the steam tem perature. This may require more heait than would be emitted from the system itself after it once is thoroughly heated. 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 . has been established,by Babcock in the following formula: . of and 1936American Society Heating Ventilating Engineers Guide, . P = 0.0000000367 ( 1 -f- or . (1) where P = loss in pressure, pounds per square inch. d = inside diameter of pipe, inches. L = length of pipe, feet. D = weight of 1 cu ft of steam. W = weight of steam flowing per hour, pounds. '. , -. Example 1. How much steam will flow per hour through 100 ft of 2-in. pipe if the initial pressure is 1.3 lb per square inch and the pressure drop is 1 oz? Solution. P = -h = 0.0625 lb; d = 2.067 in. (Table 1. Chapter 34); L = 100 ft; lo . D = 0.04038 lb (Table 6, Chapter 1). Substituting these values in Formula 2: V + wW = 5220 0.0625 X 0.04038 X 2.067 (1 )100 97.2 lb per hour. Formula 2 does not allow for entrained water in lowrpressure steam, condensation in pipe, and roughness in commercial pipe as found in practice. The latent heat of steam (htg) at atmospheric pressure (Table: 6, Chapter 1) is 970.2 Btu per pound. Inasmuch as the heat emission of an equivalent square foot of heating surface (radiation) is 240 Btu, 1 lb Of steam at this pressure will supply 9700'2 or 4.04 sq ft of equivalent heat.ing surface. This figure is usually taken as 4 even. In Example 1, the weight of steam flowing per hour would therefore supply 4 X 97.2 or 388.8 sq ft of equivalent heating surface:" . PIPE SIZES . The determination of pipe sizes' for 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 the end of the return system. _ '' 2. The maximum velocity of steam allowable for quiet and dependable operation of the system. 3. The equivalent length of the run from the boiler or source of steam supply to the farthest heating unit. ' . 4. Unusual conditions in the building to be heated. 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 im portant that (1) the total pressure drop does not exceed the initial pressure of.the system; (2) the pressure drop is not so great as to cause excessive velocities; (3) there is a constant initial pressure, except on systems 558 . 32--Chapter Piping for Steam Heating Systems Table 1. Maximum Allowable Capacities of Up-Feed Risers for One-Pipe Low Pressure Steam Based on A. S. H. V. E. Research Laboratory Tests Pips Sob Inches Velocity Feet Per Second Pressure Drop Ounces pbb 100 Ft A i m m 2 * m 3 3K .4 B 14.1 17.6 20.0 23.0 26.0 29.0 31.0 32.0 C 0.68 0.66 0.66 0.57 0.54 0.48 0.44 0.39 8q Ft Radiatioa D . 45 98 152 288 464 799 1144 1520 Capacity Btu per Hour E 10,961 23,765 36,860 69,840 112,520 193,600 277,000 368,000 Lb Steam per Hour F 11.3 24.5 38.0 72.0 , 116.0 199.8 286.0 380.0 INSTRUCTIONS FOR USING TABLE 1 , l. Capacities given in Table 1 should never be exceeded on one-pipe risers. ............................ 2. Capacities are based on X-lb condensation per square foot equivalent radiation and actual diameter of standard pipe. 3. All pipe should be well'reamed and free from constrictions. Fittings should be up to size. (See Tables 4 and 5). specially designed for varying initial pressures, such as the sub-atmos pheric which normally operate under controlled partial vacua, the orifice, and the vapor systems which at times operate under such partial vacua as may be obtained due to the condition of the fire; (4) there is sufficient difference in level, for gravity return systems, between the lowest point on the steam main, the heating units, and the dry return,, when considered in relation to the boiler water line. . . AH systems should be designed for a low initial pressure and a reason ably small pressure drop for two reasons: first, the. present tendency, in steam heating unmistakably points toward a constant lowering of pres sures even to those below atmospheric; second, a system designed in this manner will operate under higher pressures without difficulty. 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 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. Laboratory experiments limit this to. the capacities given in Tables 1 and .2 for vertical risers'and in Table 3 for horizontal pipes at varying grades. . : : ;. , - : ' Maximum Velocity and Reaming The capacity of a steam pipe in any part of a steam system depends upon the quantity of condensation present, the direction in which the 559 American Society 0/ Heating and Ventilating Engineers Guide, 1936 Table2: ^Maximum Allowable5 Capacities' of Up-Feed Risers for Two-Pipe Low'"Pressure Steam Based on A. S. H. V: E Research Laboratory Tests ., Pipe Sub-- Inches _____ Yblocitt--------Feet per Second Pressure Drop - Ounces ' per 100 Ft- - Sq Ft Radiation . Capacitt Btu per Hoar ., Lb Steam per Hour ............... A.'..._____ _____ B C.......... -............ .D . . .E . . F. ,,.... . x ._. 20 '............. .............. --- ' ....... 40 9550 . ... 10.0 ............. i 23.. __________ ....... 1.78 . 74 17,900 . 18.45 -- IK :. - .. . .27............. ..1.57 151 36,500 37.65 ........i'A.......... 30................ ........... . .1.48 228 . . 55,200 . 57.0 2 ...........35 ' _... 1.33 . . 438 106,100 . 109.5 ... 2'A . ... 38' .. 1.16 . 678 164,100: . 169.4 3. ._ 41 . . 0.95 1129 273,500 282.2 3K7 42 0.81' ' 1548 375,500 387.0 4 43 : 0.71 2042 - - : 495,000 510.5 ...........` ........................ INSTRUCTIONS FOR USING TABLE 2 ' - i 1. The capacities given in this table should never be exceeded on-two-pipe risers. 2. Capacities are based on J^-lb. condensation per square foot equivalent radiation and actual diameter of standard pipe. .. - ' ,3. :AH pipe'should he.well reamed and-free from constrictions. Fittings should be up to si2e. (See Tables.4 and 5.) . condensate 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 con densate must flow against the steam, even in limited quantity, the ve locity of the steam must not exceed limits above which the disturbance between the steam and the counter-flowing water may produce object ionable 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, hori zontally, and (3) the quantity of condensate flowing against the steam. Two factors of uncertainty always exist in determining the capacity of any steam pipe. The-first is variation in manufacture, which apparently cannot be avoided and which caused an actual difference of 20 per cent in the capacity of a 1-in. pipe in experiments carried on at the A.S.H.V.E. Research Laboratory (Table:4). The second'is the reaming of the endsof the pipe after cutting,, which, experiments indicate, might reduce the. capacity of a Inn. pipe as much as 28.7 per cent. (Table 5). All of the capacity tables given in this chapter include a factor of safety. However, the pipe on which Table 4 is based showed no particular defects or con strictions on the inside, and the factor of Safety referred to does not cover abnormal defects or constrictions nor does it cover pipe not properly reamed. Chapter 32--^-Piping for Steam Heating Systems Table 3. Comparative Capacity of Steam Lines at Various Pitches3 Pitch of Pipe in Inches per 10 Ft .............................. ..... Pitch of Pipe X IN. Pipe Sise Inches Sq Ft Rad. Based on 240 Btu > 1 2 M IN. Sq Ft Rad. Based on 240. Btu i s 1 IN. 1H IN. Sq Ft Rad. Based' on 240 Btu Sq Ft >- 1 2 Rad. Based on 240 Btu Max.Vel. 2 m. 3 IN. 4 IN. - -5 IN..-. Sq Ft Sq Ft Sq Ft Sq Ft Rad. Rad. Rad. Rad. :3.. Based on 240 Btu 1 2 Based' on 240 Btu a 2 Based on 240 Btu MS 2 Based' on 240 Btu S3 2 M 25.0 12 30.3 14 37.3 18 40.4 19 42.5 20 46.1 21 47.5 22 49.3 23 45.8 12 52.6 15 63.0 17 70.0 20 75.2 22 83.0 * 23 87.9 25 90.2 26 1 104.9 18 117.2 20 133.0 23 144.5 25 154.0 27 165.0 28 172.6 29 178,2 31 142.6 18 159.0 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 Data from A.S.H.V.E. Research Laboratory. Equivalent Length of Run All tables for the flow of steam in pipes, based on pressure drop, must allow for the friction offered by the pipe as well as for the additional resistance of the fittings and valves. These resistances generally are stated in terms of. straight pipe; in other words, a certain fitting will produce a drop in pressure equivalent to so many feet of straight run of the same size of pipe. Table 6 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 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 is 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. Table 4. Per Cent Difference in Capacity for Carrying Steam and Condensate Due to Variation of Pipe Size and Smoothness3 Maximum Condensation, Lb per Hour Size of pipe Minimum Maximum................................. ........ Per cent variation______________________ X In. 14.00 15.20 8.6 1 In. 24.89 30.08 20.8 . IX In. . . 45.42 52.08 14.7 IX In. 70.50 82.00 16.3 "Data from American Society of Heating and Ventilating Engineers Research Laboratory. Table 5. Effect of Reaming Entrance to One-Inch One-Pipe Risers* Reamed entrances............. i........... Rounded entrances. .......... . Squared entrances Three wheel cutter..... Single wheel cutter Maximum Capacitt op Riser 24;7 lb per hour 23.9 lb per hour 19.2 lb per hour 17.6 lb per hour Per Cent Decrease 00 3.2 10.1 22 2 28.7 "Data from American Society of Heating and Ventilating Engineers Research Laboratory.' 561 of andAmerican Society Heating Ventilating-Engineers Guide, 1936 6.Table Length in Feet of Pipe to be Added to Actual Length of Run-- ' 'r>----------------- --C^mvAT rMT T.RNOTR Sob or Pipe Inches St*d. Elbow Side Outlet Tee Gats Valve Globe Valve Angle Valve Length in Feet to be Added to Run 2 2H 3 ZVi 4 5 6 7 8 9 10 12 14 5 16 7 20 10 26 12 31 14 35 18 44 22 50 26 55 31 63 35 69 39 76 47 90 53 105 2 3 3 4 5 7. 9 10 12 13 15 18 20 18 25 33 39 . 45 57 70 82 94 105 118 140 160 9 12 16 19 22 28 32 37 42 47 52 63 72 Example of length in feet of pipe to be added to actual length of run. heasueed lensth. - Bi'.. -o" ------ -.13^0' %-6ATE YALJE. EL B0YY5. 3-0 - 56 :0.- ! EQUIVALENT LENGTH- 193-0' 1 ' .............. ..........H TABLES FOR PIPE SIZING1 Factors determining the size of a steam pipe and its allowable limit of capacity are as follows: . 1. Pipe condensate flowing with steam. 2. Pipe condensate flowing against steam. 3. Pipe and radiator condensate flowing with steam. . 4. Pipe and radiator condensate flowing against steam. , . . It is apparent that (3) and (4) are practically limited to one-pipe systems while (I) and (2) cover all other systems. . Tables. 7 and 8, worked out for determining pipe sizes, have their col umns lettered continuously, Columns A through Z. being in Table 7, and M through EE in Table 8. In the following text, reference made to columns will be by letter. The tables are based on the actual inside diameters of the pipe and the condensation of ^ lb (4 oz) of steam per square foot of equivalent direct radiation2 (abbreviated EDR) per hour. The drops indicated are drops in pressure perTOO ft of equivalent length of run. The pipe is assumed to be well reamed without unusual or notice able defects. .- ' *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. Values of pressure drops, formerly expressed in ounces, are now expressed in fractions of a pound. *As steam system design has materially changed in recent years so that 240 Btu no longer expresses the heat of condensation from a square foot of radiator surface per hour, and as present day.heating unita have different characteristics from older forms of radiation, it is the purpose of The Guide to gradually eliminate the empirical expression squarefoot of equivalent direct radiation, EDR, and to substitute a logical unit based on the Btu. The new terms to express the equivalent of 1000 Bfii-(Mb), and-lOOO Btu per hour (Mbh), have been approved by the A.S.H.V.E. 562 Chapter 32--Piping for Steam Heating Systems Table 7. Steam Pipe Capacities Capacity Expressed in Square Feet of Equivalent Direct Radiation (Reference to this table will be by column letter A through L) This table is based on pipe size data developed through the research investiga tions of the American Society op Heating and Ventilating Engineers. -------- CAPACITIES OF STEAM MAINS AND. RISERS DmxcnoN op Condensation Flow in Pipe Line Special Capacities pos Owb-Pipb Systems Onlt Pips Sm With the Steam in One-Pipe and Two-Pipe Systems */n lb MOz Drop >/* lb HO* Drop Vis lb 1 Os Drop K lb or 2 Os Drop K lb 40s Drop Hib . Two-Pipe Only 80s Drop Vertical Hori zontal Risers Up- Feed Radiator Radiator and. and Riser Con nections Run outs AB C D E F G . * Jb K Lc 30 30 25 i 39 46 56 79 in 157 56 26 45 lM 87 100 122 173 245 346 122 58 98 lH 134 155 190 269 380 538 190 95 152 2 273 315 386 546 771 1,091 386 195 288 2H 449 518 635 898 1,270 1,797 635 395 464 3 822 948 1,163 1,645 2,326 3,289 1,129 700 799 3H 1,228 1,419 1,737 2,457 3,474 4,913 1,548 1,150 1,144 4 5 6 8 10 1,738 2,011 2,457 3,475 3,214 3,712 4,546 6,429 5,276 6,094 7,462 10,553 10,983 12,682 15,533 21,967 20,043 23,144 28,345 40,085 4,914 9,092 14,924 31,066 56,689 6,950 12,858 21,105 2_,0_42 __ 1,700 3_,1_5_0 1,520 ;____ 43,934 __ 80,171 __ ___ 12 32,168 37,145 45,492 64,336 90,985 128,672 16 60,506 69,671 84,849 121,012 169,698 242,024 -- -- -- 20 20 55 55 81 81 165 165 260 475 745 1,110 2,180 -r-- -- AH Horizontal Mains and Down-Feed Risers I UpFeed Risers Mains and Un dripped Run outs UpFeed Risen Radiator Con- sections Run outs Not Dripped Note,--All drops shown are in pounds per 100 ft of equivalent run--based on pipe properly reamed. Do not use Column H for drops of 1/24 or 1/32 lb; substitute Column C or Column B as required. bDo not use Column J for drop of 1/32 lb except on sizes 3 in, and over; below 3 in. substitute Column B. <On radiator runouts over 8 ft long increase one pipe size over that shown in Table 7. . Convriaht f Americas Society op Heating and Ventilating Engineers \ Not to be Reprinted Wlth- \x>pyngn | Heating, Piping and Air Ctmdituming Contractors National Auoeialion J out Special Permission Table 7 may be used for sizing piping for steam heating systems by 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 condensation flow in . the same direction, while Columns H and I are for cases where the steam and condensation 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 critical velocities of the steam to permit the counter flow of condensation without noise. Sizing of return piping may be done with the aid of Table 8 where pipe capacities for wet, dry, and vacuum return lines are shown for the pressure drops per 100 ft corresponding to the drops in Table 7. It is customary to use the same pressure drop on both the steam and return sides of a system. 563 1936American Societ? of Heating and Ventilating Engineers Guide, 8- :*-.0QQO ^fO*0^00OfS \ trO- 8ooooooqo< OOOOQOOOC ooooo 0HTi0tC0MnOOQO -o\00o-oH*o-<o`",oCNoCN vOOtoOii^NONO v oin oo \ o cmo oo 8 OOOOOgOOO n0So0^On0nO0OnO oOiifiOvOO f0,"v|s0. r^^ v1O/) fIOO .iO-l N O om lOOiWN'd'NOO' m HtOlOW^N' 564 st-scs :x x ,-H \r C o f ^ 1** -. 1 'i i r ^ S ^ :r.. _____________________} " _______________ V S S t S ^ S S i S m m to be R Prln re d W ith o u t Special Perm ission Chapter 32--Piping for Steam Heating Systems 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-lb gage? ........... ......... - ............. ............... 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 lb or less. With a pressure drop of 1 lb and a length of run of 1,000 ft, the drop per 100 ft would be Ho lb, while if the total drop were H lb', the drop per 100 ft would be Ho lb- In the first instance the pipe could be sized according to Column D for H6 lb per 100 ft, and in the second case, the pipe could be sized according to Column C for H4 lb- 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 dr the column for the next lower drop must be used and the lines resized. Ordinarily resizing will be unnecessary. ONE-PIPE GRAVITY AIR-VENT SYSTEMS One-pipe gravity air-vent systems in which the equivalent length of run does not exceed 200 ft should be sized as follows: 1. For the steam main and dripped runouts to risers where the steam and condensate flow in the same direction, use H6'lb drop (Column.D). 2. Where the riser runouts are not dripped and the steam and condensation flow in opposite directions, and also in the radiator runouts where the same condition occurs, use Column L. 3. For up-feed steam risers carrying condensation back from the radiators, use Column J, 4. For down-feed systems the main risers of which do not carry any radiator con densation, 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 34 lb. The return piping sizes should correspond with the drop used on the steam side of the system. Thus, where H4-lb drop is being used, the steam main and dripped runouts would be 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 tie noted that if Column H is used the drop would exceed the limit of H4 lb); the dry return from Column R; and the wet return from Column Q. : With a t^-lb drop the sizing would be the same as for ]4i lb 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 N. Example 8. Size the one-pipe gravity steam system shown in Fig. 1 assuming that this is all there is to the system or that the riser and run shown involve the longest run on the system. ;. ! Solution. The total length of run actually shown is 215 ft. ' If the equivalent length of run is taken at double this, it will amount to 430 ft, and with a total drop of H lb the drop per 100 ft will be slightly less than lb. It would be.welkin this case to use H4 lb, and this would result in the theoretical sizes indicated in Table 9. These theo- 565 of andAmerican Society Heating Venerating Engineers Guide, 1936 Table 9. . Pipe Sizes foe One-Pipe Up-feed System Shown in Fig. 1 Plot or Stbtek Branches to radiators.. Branches to radiators. Riser---------------------Riser............--............. Riser_______________;Riser-------------------------Riser Branch to riser.. Dry return main___ Wet return main-- Wet return main.-- Wet return main..... Section or Pips --: a to 6 b to c ctod d toe e to/ / tog g to h h to j f to k fe to tn to n top Radiation Supplied (Sq Ft) Theoretical Pips bizb (Inches) Practical Pipe size (Inches) 100 50 200 300 400 500 . 600 600 600 600 600 600 600 600 2 IK 2 2K 2K 3 3 3K 3 2K IK l l l 2 IK 2 zK- 2)4 3 3 3 34 3 3 2 2 2 2 Fig. X. Riser, Supply Main and Return Main CImr.P,p,, SvsTEM Fran BMw m retical sizes, however, should be modified by not using a wet return less than 2 in. while the main supply, g-h, if from the uptake of a boiler, should be made the full size of the main, or 3 in. Also the portion of the main k-m should be made 2 in. if the wet return is made 2 in. ' Notes on Gravity One-Pipe Air-Vent Systems '. 1. Pitch of mains should be not less than K in. in 10 ft'. . 2. Pitch of horizontal runouts to risers and radiators should not be less than K in. in 10 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 main less than 2 in. The diameter of :the far end. of .the supply main should be not less than half its diameter at its largest-part. 4. Supply mains, branches to risers, or risers', should be dripped where necessary. TWO-PIPE GRAVITY AIR-VENT SYSTEMS ; The method employed in'determining pipe sizes for two-pipe gravity air-vent systems is similar to that described for one-pipe systems- except that the steam mains never carry radiator condensation. The drop allowable per 100 ft of equivalent run is obtained by taking the equiva lent length to the farthest radiator as double the actual distance, and then dividing the allowable or desired total drop by the number of hundreds of feet in the equivalent length. Thus in a system measuring 400 ft from the boiler to the farthest radiator, the approximate equivalent length of run would be 800 ft. With a total drop of 34 lb the drop per 100 ft would be ~ or 34 lb; therefore, Column D would be used for all O ... . steam mains where the condensation and steam flow in the same direc tion. If a total drop of 34 lb is desired, the drop per 100 ft would be be lb Chapter 32--Piping for Steam Heating Systems and Column B would be used. If the total drop were to be 1 lb, the drop per 100 ft would be 34 lb and Column E would be used. For mains and riser runouts that are not dripped, and for radiator runouts where in all three cases the condensation and steam flow in opposite directions, Column I should be used, while for the steam risers Column H should be used unless the drop per 100 ft is K* lb or J4 lb, when Columns B or C should be substituted so as not to exceed the drop permitted. On an overhead down-feed system the main steam riser should be sized by reference to Column H, but the down-feed steam risers sup plying the radiators should be sized by the appropriate Columns B through G, since the condensation flows downward with the steam through them. The riser runouts, if pitched down toward the riser as they should be, are ' sized-the same as the steam mains, and the radiator runouts are made the same as in an up-feed system. In either up-feed or down-feed systems the returns are sized in the same manner and on the same pressure drop basis as the steam main; the return mains are taken from Columns 0, R, U, X, or AA according to the drop used for the steam main; and the risers are sized by reading the lower part of Table 8 under the column used for the mains. The hori zontal runouts from the riser to the radiator are not usually increased on the return lines although there is nothing incorrect in this practice. The same notes apply that are given for one-pipe gravity systems. TWO-PIPE VAPOR SYSTEMS While many manufacturers of patented vapor heating accessories have their own schedules for pipe sizing, an inspection of these sizing tables indicates that in general as small a drop as possible is recommended. The reasons for this are: (1) to have the condensation return to the boiler by gravity, (2) to obtain a more uniform distribution of steam throughout the system, (3) because with-large variation in pressure the value of graduated -valves on radiators is destroyed. 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, 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 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 correspond. This will not hold true in larger systems. . For vapor systems over 200 ft of equivalent length, the drop should not exceed 34 lb to 34 lb, if possible. Thus, for a 400 ft equivalent run the drop per 100 ft should be not over 34 lb divided by 4, or 34 lb. In this case the steam mains would be sized from Column B; the radiator and 567 American Society of Heating and Ventilating Engineers Guide, 1936 undripped riser runouts from Column I; the risers from Column B. because Column H gives a drop in excess of ^ lb.- 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 lb. The return risers would be sized from the lower portion of Column O and the dry return main from the upper portion of the same column, while any wet returns wouid 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 be not less than % in. in 10 ft. .. 2. Pitch of horizontal runouts to risers and radiators should be not less than H in. in 10 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., and when the supply main is 3 in. or over at the boiler or pressure reducing valve it should be not less than 2y in. at the far end. 4. When necessary, supply main, supply risers, or branches to supply risers should be dripped separately into a wet return. The drip for a vapor system may be connected into the dry return through a thermostatic drip trap. . VACUUM SYSTEMS Vacuum systems are usually employed in large installations and have total drops varying from to lb. Systems where 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 go to 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 lb divided by 12, of Ac lb. In this case the steam main would be sized from Column C, 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 M4 lb). 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 5; return runouts to radiators, one pipe size larger than the radiator trap connections. .' Notes on Vacuum Systems . .' 1. It is not generally considered good practice to exceed -lb drop per 100 ft of equivalent run nor to exceed 1 lb total pressure drop in any system. . 2. Pitch of mains should be not less than A in. in 10 ft. 3. Pitch of horizontal runouts to risers and radiators should be not less than Vi in. in 10 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. When the supply main is 3 in. or over, at the boiler or pressure reducing valve, it should be not less than 2j in. at the far end. 5. When necessary, the supply main, supply riser, or branch 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 Chapter 31 under Up-Feed Vacuum Systems. 568 Chapter 32--Piping for Steam Heating Systems ATMOSPHERIC SYSTEMS The sizing of the supply and return piping on atmospheric systems is practically identical with the sizing used for vacuum systems and the same notes apply, except that no lift can be made in the return line. SUB-ATMOSPHERIC SYSTEMS Any properly pitched, correctly sized vacuum system without a lift may be used as a sub-atmospheric system when the proper equipment is substituted for the ordinary vacuum pump, traps, and controls: On new systems manufacturers usually recommend a drop oh the steam line of between M and Vs lb for the total run, and suggest adding 25 ft to the `.''total equivalent length of run to insure that the.steam gets through to the i? last radiator. ...... , The same notes apply to these systems as for vacuum systems, except that no lifts can be made in the returns. ' ORIFICE SYSTEMS................. ....................... The orifice systems can be operated with any piping system suitable for vacuum operation, according to experienced designers. Because these systems vary considerably in detail, it is advisable to consult the manu facturer of the particular system contemplated for recommendations. The same notes apply to these systems as to vacuum systems, except that lifts cannot be made in the returns of orifice systems if a vacuum pump is used. HIGH PRESSURE STEAM When steam heating systems are supplied with steam from a high pressure plant, one or more pressure-reducing valves are used to bring the pressure down to that required by the heating system. It has been con sidered good practice to make the pressure reductions in steps not to exceed 50 lb in each case. For example, in reducing from 100-lb gage to 2-lb gage, two pressure reducing valves would be used, the first reducing the pressure from 100-lb gage to 50 lb and the second reducing the pressure from 50-lb gage to 2-lb gage. Valves are available that will reduce 100 lb in one step, and it is questionable whether two valves are now required for initial pressures of 150 lb or less. . The pressure-reducing valve, or pressure-regulator as it is sometimes termed, has ratings which vary 200 to 400 per cent. Some of these ratings are based on arbitrary steam velocities through the valve of 5,000 to 10,000 fpm and it is assumed that the valve when wide open has the same area as the pipe on the inlet opening of the valve. At times it is considered desirable to keep the steam velocity in the high pressure section of the piping and the low pressure section Constant. The velocity thro.ugh the valve port is obviously a function of the pressure drop across the valve. It is well known that steam flowing through an orifice increases its velocity until the pressure on the outlet side is reduced to 58 per cent of the absolute pressure on the inlet side, and that with further reduction of pressure on the outlet side little change in velocity will be obtained. As practically all pressure-reducing valves used for steam heating work 569 . American Society of Heating and Ventilating Engineers Guide, 1936 lower the steam pressure to less than 58 per cent of the inlet pressures, only the maximum velocity through such valves need be considered. If it is assumed that the valve, when fully open, has an area equal to that of the inlet pipe size; that the steam is flowing into a pressure less than 58 per cent of the initial pressure, that the orifice efficiency is approx imately 70 per cent, and that 20 per cent more is allowed for a factor of safety, then the pressure reducing valves will have the working capacities shown in Table 10. If the valve, when fully open, does not give an orifice area equal to that of the pipe on the inlet side, then the capacities will be proportional to the percentage of opening secured, taking the pipe area as 100 per cent. More frequently difficulty is encountered from the use ' of pressure reducing valves which are too large in size instead of being Table 10. Capacities of Pressure-Reducing Valves (100-lb Gage Down to any Pressure--52 lb or Less) Inlet Nominal Pot Diameter (Inches) k K l IK IK 2 2K 3 3K 4 5 6 Pounds Steam. per Hour at 100-Lb Gaos 866 1,576 2,459 4,263 5,808 9,564 13,623 21,041 28,213 36,285 56,971 82,336 Equivalent Direct Radiation Sq Ft at X Lb 3,464 6,304 9,836 17,052 23,232 38,256 54,492 84,104 112,852 145,140 227,884 329,344 Equivalent Direct Radiation Sq Ft at */s Lb 2,598 4,728 7,377 12,689 17,424 28,692 40,86963,123 84,039 108,855 170,913 247,008 Formula: ' A ^X = pounds per hour passed by orifice. 144 X 3.00 where '. . - A area of inlet pipe, square inches. ' . V = velocity of steam.through orifice (approximately 870 fps). 50 = 70 per cent efficiency of orifice less 20 per cent for factor of safety. 144 *= square inches in 1 sq ft. . *. ` 3600 = seconds in one hour. . 3.88 =* cubic feet per pound at 100-lb gage. . ' ' , too small. Where valves are large in size, the valve tends to work close to the seat, causing it to cut out in a relatively short time, as well as being noisy in operation. Most exact regulation of pressure on steam heating systems is secured from diaphragm-operated valves controlled by a pilot line from the low pressure pipe, taken off the low pressure main at least 15 ft from the reducing valve. The-reducing valves operating on the proportionalreduction principle will give a variation of steam pressure on the low pressure side if the initial pressure varies between considerable limits. The so-called dead-end valve is used for reduced pressures where the line has not sufficient condensing capacity at all times to condense the leakage that might occur with the ordinary valve. Single-disc valves do not give as close regulation as double-disc valves, but the single disc is preferable where dead-end valves are necessary, such as on short runs to thermo- 570 Chapter 32--Piping for Steam Heating Systems statically controlled hot water heaters, centred fan heating units and unit heaters. . The correct installation (Fig. 2) of a pressure-reducing valve includes a pressure-reducing valve with a gate valve on each side, a by-pass con trolled by a globe valve, a pressure gage on the low pressure side, and a safety valve on the low pressure main at some point, usually within a reasonable distance of the pressure-reducing valve. Pressure-reducing valves should have expanded outlets for sizes greater than 2 in. Where the steam main is of still larger diameter than the expanded outlet, and in cases where straight valves are used, an increaser is placed close against the outlet of the valve to reduce the velocity immediately after passing through the valve. Strainers are recommended on the inlets of all pressure-reducing valves. A pressure gage may be located on the highipressure line near the valve if desired. Owing to the large variation in steam demand on the average heating system, it is generally advisable to use two pressure-reducing valves con- Less trouble from expansion leaks will occur when the bypass Fig. 2. Typical Pressure-Reducing Valve Installation nected in parallel. One valve should be large enough for the maximum load and the other should have a diameter approximately half that of the first. The smaller valve can be used most of the time, for it will give much better regulation than the larger one on light or normal loads. Control Valves - Gate valves are recommended in all cases where service demands that the valve be either entirely open or entirely closed, but they should never be used for throttling. Angle globe valves and straight-globe valves should be used for throttling, as done on by-passes around pressure reducing valveis or on by-passes around traps. EXPANSION IN STEAM AND RETURN LINES Because all steam and return lines expand and contract with changes in temperature, provision should be made for such movement. The expansion in steam supply pipes is normally taken at 134 to in. per 100 ft and in return lines at one-half or two-thirds of this amount. It may be calculated accurately if the temperature rise and fall can be determined with reasonable certainty (Page 616, Chapter 34). The tem perature at the time of erection often has a greater expansion effect on piping than the temperature in the building after it has been put into service. 571 American Society of Heating and Ventilating Engineers Guide, 1936 Expansion may be taken care of by any, or all, of three different methods, namely, (1) the spring in the pipe including offsets and expan-' sion bends, (2) the turning of the pipe on its threads and swing joints, and (3) the use of expansion joints. . . By the first scheme, which is the most popular method where space permits, the pipe is offset, or broken, around rooms or corners, and is hung so that the spring in the pipe at right angles to the expansion movement is sufficient to absorb the expansion. If conditions do not lend themselves to this treatment, regular expansion bends of the U or offset type may be used. In tight places such as pipe tunnels the expansion, joint is pre ferable. See additional material on pipe expansion bends in Chapter 34. On riser runouts and radiator runouts the swing joint is used almost without exception. On high vertical risers the pipes may be reversed every five to ten stories; that is, the supply is carried over to the adjacent return riser location and the return riser; is run over to the former supply riser location, thus making horizontal offsets in each line. Corrugated copper expansion joints also are used on risers but must be made.acces sible in case future replacement becomes necessary. PIPING CONNECTIONS AND DETAILS Piping connections may be classified into two groups: first, those suitable for any system of steam heating; second, those devised for certain systems which cannot be satisfactorily applied to any other type. There are also various details that apply to piping on the steam side which cannot be used on the returns. An installation that is designed and sized correctly and installed with care may be rendered defective by the use of improper connections, such as runouts that do not allow for expansion, thermostatic traps unprotected from scale, pressure-reducing valves without strainers, and lack-of drips at required points. BOILER CONNECTIONS Supply Boiler headers and connections have the largest sizes of pipe used in a system. Cast-iron, horizontal-type, low pressure heating boilers usually have several tapped outlets in the top, the manufacturers recommending their use in order to reduce the velocity of the steam in the vertical up takes from the boiler and to permit entrained Water to return to the boiler instead of being carried over- into the steam main where it must be cared for by dripping. Steel heating boilers usually are equipped with only one steam outlet but many engineers believe that better results are obtained by specifying that such boilers1 have two. The second outlet, usually located 3 or 4 ft back of the regular..one, reduces the velocity 50 per cent in the steam uptake. .. Fig. 3 shows a type of boiler connection that was used for many years and one with which some boilers are now piped. The uptakes are carried as high as possible,. turned horizontally and run out to the side of the boiler and then are connected together into the main boiler runout which drops into the top of the boiler header through: a boiler stop valve. No drips are provided on. this type of runout except a very small one which is sometimes installed on the boiler side of the stop valve. Fig. 4 shows a 572 Chapter 32---Piping for Steam Heating Systems' type of boiler connection which is regarded as superior- to that shown in Fig. 3 and which is the type illustrated in the system diagrams in Chapter 31. This type is similar to that shown in Fig. 3 except that the horizontal branches from the uptakes are connected into the main boiler runout, and the steam is carried toward the rear of the boiler. The branch to the building or boiler header is taken off behind the last horizontal boiler con nection. At the rear end of this main runout, a large size drip, or. balance pipe, is dropped down into the boiler return, or into the top of the Hart ford Loop, which is described in a following paragraph. As a result, any water carried over from the boiler follows the direction of steam flow Fig. 3. Old Style Standard Boiler Connections Fig. 4. Approved Method of Boiler Connections toward the rear and is discharged into the rear drip, or balance pipe, without being carried over into the system. . Return Cast-iron boilers are generally provided with' return tappings on both sides; but steel boilers often are equipped with only one return tapping. A boiler with side return tappings will usually have a more effective cir culation if both tappings are used. Check valves generally should not be used on the return connection to steam heating boilers from one and two pipe gravity systems because they are not always dependable inasmuch as a small piece of scale or dirt lodged on the seat will hold the tongue open and make the check useless. These valves also offer a certain amount of: resistance to the returns coming back to the boiler, and in gravity systems will raise the water line in the far end of the wet return several inches3: However, if check valves are omitted and the steam pressure is raised with the boiler steam valve closed, the water in the boiler will be blown out into, the return system with the accompanying danger of boiler damage. These objections are : largely overcome with the Hartford return connection. - See.method of calculating height above water line for gravity one-pipe systems in Chapter 31.* ' 573 ' American Society of Heating and Ventilating Engineers Guide, 1936 Hartford Return Connection In order to prevent the boiler from losing its water under any circum stances, the use of the Hartford Connection, or the Underwriters Loop, is recommended. Fig. 5 shows this connection for a two-boiler installation. For a single boiler installation the connection is made as is indicated for one boiler. The essential features of construction of a Hartford Loop 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 con nection about 2 in. below the normal boiler water line from the return main to the boiler steam and return balance connection. Fig. 5.' The Hartford Return Connection Sizing Boiler Connections '' Little authentic information is; available on the sizing of boiler runouts and steam headers. Although many 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 com: puting the maximum load that must be carried by any portion of the header under any conceivable method of operation, and then applying the same schedule of pipe sizing to the header as is used on the steam mains for the building. The horizontal runouts from the boiler, or boilers, may be sized by calculating the heaviest load that will be placed on the boiler at any time, and sizing the runout on the same basis as the building mains. The difference in size between the vertical uptakes from the Chapter 32--Piping for Steam Heating Systems Fig. 6. Boiler Steam Header and Connections boiler and the horizontal main or runout is compensated for by the use of reducing ells (Figs. 3 and 4). The following example illustrates the sizing of the boiler connections shown in Fig. 6. Example 4- Determine the size of boiler steam header and connections (Fig. 6) if there are three boilers, two to carry 50 per cent of the load each, and the third to be used as a spare. The steam mains are based on )4-lb drop per 100 sq ft of equivalent direct radiation (EDR). Solution: . Size of Boiler Header Whin on Boilers Nos. 1 and 2 Nos. 2 and 3 Nos. 3 and 1 Max. Load A 6000 6000 6000 6000 Load on Varioub Portions of Header B 0 6000 0 6000 C 2000 8000 2000 8000 D 4000 2000 2000 4000 E 3000 3000 3000 3000 F 3000 3000 3000 3000 Load 6000 8000 6000 8000 8000 sq ft @ lb per 100 ft = 6 in. main. (See Table 7.) The three runouts Size of Boiler Runouts . - 222.Ci, Gj, Gi = -- 2667 sq ft each @ 34 lb per 100 ft = 4 in. pipe. . Hi, Hi, Hi 2667 sq ft each @ 34 lb per 100 ft = 4 in. pipe4 (See Table 7). Ji, Ji, Ji = 5333 sq ft each @ 34 lb per 100 ft = 5 in.pipe4 (See Table 7). ki, Ki, K, = 8000 sq ft each @ 34 lb per 100 ft = 6 in. pipe4 (See Table 7). The uptakes from the boiler probably would be 6 in. pipe with a 6 in. X 4 in. reducing ell at top. ' f `ute'iS^S carry 8000 sq ft and are 6 in. pipe, the whole runout including Ji, J, and Ji ana.Ni. and Hi and the leads from the boiler headers :to the main steam header would also be made o m. pipe. , 575 American Society of Heating .and Ventilating Engineers Guide, 1936 Fig. 10. Top and Bottom Radiator Connections from Up- or Down-Feed Risers. (Not to Exceed 8 to 10 Sections.) Note.--Suitable for. up-feed or down-feed at mospheric, vapor, vacuum, sub-atmospheric, and orifice systems. Opposite end connections always preferable. Fig. 7. Typical One-Pipe Radiator Connections (Up-Feed or Down-Feed) Fig. 8. Connections to Steam-Type Radiator for Two-Pipe Gravity System, Up-Feed or Down-Feed . No*<r.--Steam-type radiators should not be used on any except gravity one-pipe and gravity twopipe systems. v . Fig. 11. Top and Bottom Opposite End Radiator Connections with Heel of ------ Down-Feed Riser Dripped into . - Dry Return . , Note.--Suitable for down-feed only. For at-- mospheric, vapor, vacuum, sub-atmospheric, and orifice systems. . Fig. 9. ' Top and Bottom Opposite End Radiator Connections from Up or Down-Feed Risers Hole.--Suitable for up-feed or down-feed at mospheric. vapor, vacuum, sub-atmospheric and orifice systems. Fig. 12. Connections to Radiator Hung on Wall Note.--For up-feed with radiators below level of steam main. For atmospheric and vapor systems. Not suitable for vacuum, sub-atmospheric, or orifice systems. 576 Chapter 32--Piping for Steam Heating Systems 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 cany. 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 operating, and the line sized for a very small pressure drop, the size being obtained from the Chart for Pressure Drop for Various Rates of Flow of Water, Fig. 3, Chapter 35. The relative boiler loads should be considered, as in the case of gravity return connections. Radiator Connections . . Radiator connections are important on account of the number of repetitions which occur in every heating installation. They must be properly pitched and they must be arranged to allow not only for move > ment in the riser but, in frame buildings, for the shrinkage of the building. In a three story building: this sometimes amounts to 1 in. or more. The simplest connection is that for the one-pipe system where only one radia tor connection is necessary. Where the radiator runouts are located on the ceiling or under the floor, sufficient space usually is available to make a good swing joint with plenty of pitch, but where the runouts must come above the floor the vertical space is small and the runouts can project out into the room only a short distance. Fig. 7 illustrates two satisfactory methods of making runouts on a one-pipe gravity air vent system of either the up-feed or down-feed type, the runout below the floor being indicated in full lines and the runout above the floor "in dotted lines. Sometimes it is necessary to set a radiator on pedestals; or to use high legs, in order to obtain sufficient vertical distance to accommodate abovethe-floor runouts. Particular attention must be given to the riser expan sion as it will raise the runout and thereby reduce the pitch. Similar connections for a two-pipe system of the gravity air vent type are' illustrated in Fig- 8 for the old steam type radiator. If the water type is used, the supply tapping is at the top instead of at the bottom, the runouts otherwise remaining as shown in Fig. 8. A satisfactory type of radiator connection for atmospheric, vapor, vacuum', sub-atmos pheric, _ and orifice systems of both the up-feed and down-feed types is . shown in Fig. 9. . ," . While short radiators, not exceeding'8 to: 10 sections, may be supplied and- returned, from "the same end as indicated in Fig. 10, the top-anv. bottom-opposite-end method is to be preferred in all cases where it can be / used. On down-feed systems of the atmospheric, vapor, vacuum/ subatmospheric, and orifice types, the bottom of the supply riser must be 577 of andAmerican Society Heating Ventilating Engineers Guide, 1936 SB 578 Chapter 32--Piping for Steam Heating Systems dripped into the return somewhat as illustrated in Fig. 11. On up-feed systems of the vapor and atmospheric types, where radiators in the basement are located below the level of the steam main, the drop to the radiator is dripped into the wet return and an air line is used to vent the return radiator connection into an overhead return line, as illustrated in Fig. 12. When the radiator stands on the floor below the main, the drip on the steam branch down to the radiator may be omitted if an overhead valve, as shown in Fig. 13, is used. This method is also suitable for vacuum, sub-atmospheric, and orifice systems. Convector Connections Convectors often are installed without control valves, a damper being used to shut off the flow of air to retard the heat transfer from the convecto'r even though it is still supplied with steam. The piping connec tions for a convector with the inlet and outlet at the same end are shown in Fig. 14. There is no valve on the steam side but there is a thermostatic trap on the return. The damper for control is shown immediately above the convector. This piping is suitable for atmospheric, vapor, vacuum, sub-atmospheric, and orifice systems of the up-feed type. A similar unit with connections on opposite ends and suitable for the same systems is shown in Fig. 15. This unit has no damper but requires a valve on the steam connection for control. _When. valves must be located so as to be accessible from the supply air grille, the arrangement usually takes the form indicated in Fig. 16. Convectors with damper control, installed in cabinets or under window sills, usually are connected as shown in Fig. 17. A convector located in the basement and supplying air to a room on the floor dbove may be piped as pictured in Fig. 18 for all systems except gravity one-pipe or two-pipe systems. Vapor, systems with heating units in the basement where the returns are wet would be treated as in Fig- 19- Similar heating units where a dry return is available would be connected as shown in Fig. 20.. If the dry return were on a vacuum,' atmospheric, sub-atmospheric or orifice system, the treatment would be identical. Pipe Coil Connections ' . Pipe coils, unless coupled in a correct manner, often give trouble from short circuiting and poor circulation. The method of connecting shown in Fig.'21 is suitable for atmospheric, vapor, vacuum, sub-atmospheric, and orifice systems. Indirect Air Heater Connections - Heating units for central fan systems have simple connections on the steam side. The steam main is.carried into the fan room and has a single branch tapped off for each row of heating units. Each of these main branches is split into as many connections as need be made to each row, governed by the number of stacks and the width of the stacks. Each stack must have at least one steam connection, and wide stacks are more evenly heated with two steam connections, one at each end. The piping shown in Fig. 22 is for small stacks and has the steam con nected at only one end. On the return side all of the returns are collected 579' American Society of Heating and Ventilating Engineers Guide, 1936 OQQEUT QAOXTOb' Thermostatic trap Fig. 20. Typical Piping Connections to Indirect Radiators with Dry Return . Note.--Suitable for atmospheric, vapor, vacuum, sub-atmospheric, and orifice systems. Full sue of tapping Reducing ell Fig. 23. Heating Unit Return Con nection with Separate Air Line Chapter 32--Piping for Steam Heating Systems together through check valves and are passed through blast traps which are connected to the vacuum return or to an atmospheric return. The air from the stacks, in the case illustrated, passes up into a small air line and through a thermostatic trap into a line connecting into the return beyond the blast trap. It is important to use a nipple the full size of the outlet tapping bn the stack and to reduce the pipe size to the'normal return size required, by the use of a reducing ell, as indicated in Fig. 23. Where the stacks contain some thirteen or more sections, an auxiliary air tapping is made to the lower portion of one of the middle sections, in the manner illustrated in Fig. 24, to prevent air collecting at this point. Thermostatic control as applied to such, heating units in modern practice Fig. 21. Typical Pipe Con. Connections Note.--Suitable for up-feed or down-feed. For atmospheric, vapor, vacuum, sub-atmospheric, and orifice systems. Fig. 22. Connections for- Heating Units of Central Fan Systems Central Fan System Heating Units Exceeding 12 Sections : ' Note.--Suitable for atmospheric and vacuum systems. > Note.--Suitable for vacuum and atmospheric systems. 580 Fig. 25. Typical Piping for Atmospheric and Vacuum Systems with Thermostatic Control (Central Fan System) consists of a thermostatic valve located in each main branch from the steam line so that each valve will open or close a Complete row of stacks across the entire face of the heating unit. The stack closest to the outside air intake usually is not equipped with, a thermostatic valve. A gate valve on the steam pipe to the first coil is operated manually to supply steam continuously in freezing weather. Good practice demands that the returns be connected in parallel with the steam supplies,, with a separate steam trap for each bank of coils having a separately vajved steam supply. This arrangement is illustrated in Figs. 22 and 25, for blast traps having external thermostatic bypasses and integral ' thermostatic bypasses, respectively. - ' \. A method of connecting a unit heater to a one pipe air-vent steam heating system is illustrated in Fig. 26. : . : ' ' 581 . American Society of Heating and Ventilating Engineers Guide, 1936 PIPE SIZING FOR INDIRECT HEATING UNITS Pipe' connections and mains for indirect heating units are sized in a manner'similar to radiators, but the equivalent direct radiation must be ascertained for each row of heating unit stacks and then must be divided into the number of stacks constituting that row and into the number of connections to each stack. where EDR Q X 60 X ft - 1,1 = Q X ft - fe) 55.2 X 240 220.8 (3) EDR = equivalent direct radiation, square feet. Q = volume of air, cubic feet per minute. = the temperature of the air entering the row of heating units under con sideration, degrees Fahrenheit. ft = the temperature of the air leaving the row of heating units under considera tion, degrees Fahrenheit. 60 = the number of minutes in one hour. 55.2 = the number of cubic feet of air heated 1 F by 1 Btu. 240 = the number of Btu in 1 sq ft of EDR. Example 6. Assume that the heating units shown in Fig. 25 are handling 50,000 cfm of air and that the rise in the first row is from 0 to 40 F, in the second row from 40 to 65 F, and in the third row from 65 to 80 F. What is the load in EDR on each supply and return connection? Solution. For row 1, R 50,000 X (40 - 0) 220.8 9058 sq ft. For row 2, R 50,000 X (65 - 40) 220.8 5661 sq ft. For row 3, 50,000 X (80 - 65) 220.8 3397 sq ft. Each row of heating units consists of four stacks and each stack has two connections so that the load on each stack and each connection of the stack is as follows: Row ` Total Load (EDR) Stack Load* (EDR) CoNNBcnozt Load* (EDR) i 9058 2265 ' . 2265 or 1132 2 5661 1415 1415 or 708 3 3397 849 %' 849 or 425 One quarter of total row load. . . ' bOne half of stack load if two steam connections are made; otherwise, same as stack load. DRIPPING . Any 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 steam flow. Any steam main in any heating system can be elevated if dripped (Fig. 27). Steam mains also may be run over obstructions without a change in level if a small pipe is carried below the obstruction to care for the condensation (Fig. 28). Return mains may be carried past doorways or other obstructions by using the scheme illustrated in Fig. 29; in vacuum systems it is well to have a gate valve in the air line. 582 Chapter 32--Piping for Steam Heating Systems TO fWOUHGmC - MULTBLV A Bf OOUSJAMT foa ANQLE 6. Fig. 30. Constants for Determining Proper Length of Offset Pipe One Pipe Air Vent System with Dry Return Note.--If connection can be made to a wet return, no 5 ft loop is required. ^ -BQM4CH I^J^LsMAM acceptable METHOD PREFEEED METHOD Fig. 31. Acceptable and Preferred Methods of Taking Branch from Main of Dripping Main Where It Rises toHigher Level Not*.--Suitable for vapor and atmospheric. systems. Fig. 28. Looping Main Around Beam. OCT POCKEW Fig. 32. Dirt Pocket Connection t-Oer BETUGH C-SUWW MAIM Fig. 29. Looping Dry ' Return Main Around Opening Suitable for any dry return line and an return-line carrying air. QEDUCNO COUPUNG-iA Fig. 33. Dripping End of Main into Wet Return Note.--Suitable for vapor systems. 583 W.TEB LINE of andAmerican Society Heating Ventilating Engineers Guide, 1936 OCT POCKET Fig. 34. Dripping End of Main into Dry Return. (A Gate Valve is Recommended at the Inlet Side of the Trap) Fig. 35. Dripping Heel of Riser into Dry Return. (A Gate Valve is .' Recommended at the Inlet Side of the Trap) The pipe sizes would then be based on the length of the run and the pressure drop desired, as in the case of, radiators. It generally is considered desirable to place the in direct heating units on a separate system and not on supply or return lines connected to the general heating system. . 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. 30. Branches from steam mains in one-pipe gravity steam systems should use the preferred connection shown in Fig. 31, but where radiator condensa tion does not flow back into the main the acceptable method shown in the same figure may be used. This acceptable method has the advantage of giving a perfect swing joint when connected to the vertical riser or radia tor connection, whereas the preferred connection does not give this swing without distorting the angle of the pipe. Runouts from the steam main are usually made about 5 ft long to provide flexibility for movement in the main. Dirt pockets, desirable on all systems employing thermostatic traps, should be so located as to protect the traps from scale and muck which will interfere with their operation. Dirt pockets are usually made 8 in. to 12 in. deep and serve as receivers for foreign matter which otherwise would be carried into the trap. They are constructed as shown in Fig. 32. On vapor systems where the end of the steam main is dripped down into the wet return, 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. 33. On vacuum systems the ends of the steam mains are dripped and vented into the return through drip traps opening into the return line. The same method may be used in atmospheric systems. A float type trap is preferable to a thermostatic trap for dripping steam mains and large risers. If thermostatic traps are used a cooling leg (Fig. 34) should always be provided. The cooling leg is for cooling the condensation sufficiently before it reaches the trap so the trap will not be held shut by too high a.temperature. On down-feed systems of atmos pheric, vapor, and vacuum types, the bottom of the steam risers are dripped in the manner shown in Fig. 35. PROBLEMS IN PRACTICE I 0 What factors determine the size of steam piping'and the allowable limit of capacity? . , . , - ; '' Factors which determine the size of steam piping are the desired initial- pressure and the allowable drop in pressure which is permissable to maintain a' pressure in the farthest 584 Chapter 32--Piping for Steam Heating Systems radiator. The length of run in sizing piping is important and it is generally considered as the distance along the piping from the source of steam supply to the farthest radiator, with allowances for resistance of elbows and valves expressed in terms of equivalent length. 2 When the size of pipe is still undetermined, what arbitrary percentage is usually added to the actual length to obtain the equivalent length? Usually 100 per cent; in other words, the actual length is doubled to allow for the added drop produced by the valves, tees, elbows, and other fittings. ' 3 What are the major factors to be considered in determining the flow of steam in pipes? a. The initial steam pressure available and the total pressure drop allowable between the source of steam supply and the end .of the return system. The pressure drop should , never exceed one half of the initial pressure. ' b. The maximum steam velocity allowable. When condensate is flowing against the steam, the velocity must not be so great as to produce water hammer, or hold up water in parts of the system until the steam flow is reduced sufficiently to permit the water to pass. The velocity at which disturbances take place depends upon: 1. Size of pipe. 2. Whether pipe is vertical or horizontal. 3. Pitch or grade of pipe. . 4. Quantity of water flowing against steam. " c. The equivalent length of run from the source of steam supply to the farthest heating unit, with allowance for friction in pipe fittings and valves. 4 Name three fundamental considerations in designing the piping system for steam heating. . a. Provision for the distribution of suitable quantities of steam to the various heating units. bt Provision for the' return of condensate from the radiators and piping to the boiler. c. Provision of means for expelling air from the radiators and piping. 5 Why is the proper reaming of the ends of pipe necessary? The capacities of pipes depend upon the free area available for flow. In cutting the pipe tins area may be restricted by a burr, which may decrease the capacity of a pipe more than 2,o per.cent;in the smaller pipe sizes. . .r . 6 a. What are the major factors to be considered when selecting a pressure1 reducing valve? b. How should such valve be installed? a. The initial pressure of the, steam must be considered along with the desired reduced pressure. I he connected load to be supplied must be known in square feet of equiva lent direct radiation or in pounds of steam per hour. For operation with a continuous load, a semi-balanced or double seated valve operated by a diaphragm gives good results. Where the load is intermittent, as in process work or with thermostatically controlled blast heaters, a so:caIled dead end of single seated valve should be used. b. The pressure reducing valve should be installed in a horizontal line with a gate valve Sld?' and with a by-pass operated by a valve. The pressure balancing pipe trom the diaphragm chamber should be connected into the top or side of the low pressure main not less than 15 ft from the reducing valve. . 1S.the usual expansion allowance and how it is compensated for in neating system supply risers? . 585 * American Society of Heating and Ventilating Engineers Guide, 1936 The expansion of low pressure steam piping is normally taken as 114 to 1}^ in. per 100 ft of pipe. With a five story building a double swing connection between the riser and the main will suffice. In buildings between 5 and 10 stories high the riser should be anchored near its center and have double swing connections to the main. For taller buildings expansion loops or riser offsets are used which are capable of handling a length of riser reaching 5 stories in either direction from the joint. The risers are anchored at each alternate 5 stories. All radiators must have double swing connections, and those con nected above where the riser is anchored must be given greater pitch to insure their having proper grade when the riser is heated. 8 Why should all boiler steam supply tappings be used full size? In order to operate at low steam velocities so the water in suspension can separate from the steam and remain in the boiler. 9 What is the Underwriters Loop of the Hartford Connection? An arrangement of piping on the returns to low pressure boilers wherein the return line is raised up nearly to the water line of the boiler and is then dropped back and con nected to the boiler return inlet; the high point is connected by a balance pipe to the steam runout from the boiler on the boiler side of all stop valves. With this loop no check valve is required, and water cannot be backed put of the boiler and into the return at a point lower than the invert of the pipe at the top of the loop. 10 What are the important factors in making radiator connections? Connections to radiators should be made as direct as possible, of proper size, with ample pitch of piping and allowance for expansion. 11 Why should careful attention be given to proper dripping and drainage of steam piping? ' The steam mains and risers must be quickly drained of condensate and where necessary vented of air in order to obtain a sufficient supply of steam to the radiators. Proper drainage is also necessary to insure a noiseless heating system. 12 What is the limit of pressure drop usually recommended in a vacuum system? Not over J4 lb (2 oz) per 100 ft of equivalent run, and not over 1 lb total drop. 13 When steam and condensation are flowing in the same direction, what is the mnrimnni total pressure drop which should be used? The maximum total pressure drop should not exceed one half of the initial steam pressure. 14 t What does a proper installation of a pressure reducing valve include? A strainer in front of the pressure reducing valve; a gate valve in front of the strainer; a gate valve after the reducing valve; a by-pass around the two gate valves, strainer, and pressure reducing valve; and a globe valve in the by-pass. Sometimes a safety valve on the low pressure side and pressure gages on both sides are installed. The high pressure line should be dripped just before the high pressure steam enters the pressure reducing valve assembly. 15 Will a pressure reducing valve which is reducing the steam pressure from 100 lb gage to 50 lb gage pass more or less steam than the same valve when reducing the steam pressure from 100 lb gage to 5 lb gage? " The valve will pass practically the same volume of steam in each case as the velocity of steam Sowing through an orifice shows no material increase after the reduced absolute pressure has fallen to 58 per cent of the initial absolute pressure. Because of its greater density, the weight of steam passed will be greater in the case of the reduction to 50 lb gage. 586 Chapter 33 HOT WATER HEATING SYSTEMS AND PIPING One- and Two-Pipe Systems, Selecting Pipe Sizes, Forced Circu lation, Effect of Variations in Pipe Sizes, Gravity Circulation, Mechanical Circulation, Expansion Tanks, Installation Details A HOT water heating system is one in which water is the medium by which heat is carried through pipes from the boiler to the heating units. There are two general types, namely, forced circulation and gravity circulation systems. In the former the pressure head maintaining flow is produced mechanically, whereas in the latter the pressure head is pro duced by the differences in weight of the water in the flow and in the return risers. The fundamental nile in the design of a hot water system is that the total friction and resistance head in any circuit must equal the pressure . head causing the water to flow in the same circuit. ,' In designing a hot water heating system, it is necessary to determine; 1. The heat losses of the rooms or spaces to be heated. (See Chapter 7.) 2. The size and type of boiler. (See Chapter 25.) 3. The location ."type, and size of heating units. (See Chapter 30.) 4. The method of piping. 5. Suitable pipe sizes. 6. The type and size of circulating pump (if forced circulation). 7. The type.and size of expansion tank. . The unit, a square foot of equivalent direct radiation, EDR, has been used for many years for rating purposes in both steam and hot water systems, but its use, especially in hot water systems, has always resulted in complications and coyifusion. It is the plan of The Guide to eventually eliminate this empirical expression and to substitute a logical unit based on the Btu. The Mb, the equivalent of 1000 Btu, and the Mbh, the equivalent of 1000 Btu per hour, which have been approved by the A. S.H.V. E., are used in this chapter on hot water systems to replace the square foot of radiation formerly used. , . ONE- AND. TWO-PIPE SYSTEMS Pipe systems may be divided into two general types, namely, two-pipe and one-pipe systems. In a two-pipe system the piping is arranged so that the water flows through only one radiator during a circuit through the system, so that all radiators are supplied with water at practically the same temperature as that in the boiler. In a one-pipe system, the water flows through more than one radiator during its circuit. In that case, the . 587 American Society of Heating and Ventilating Engineers Guide, 1936 first radiator receives the hottest water; the second radiator, somewhat cooler water; the third one, still cooler; and so on. As the temperature of the water supplied to a radiator is lowered, the size of the radiator must be increased and, consequently, the total heating surface for a one-pipe system must be greater than that for a two-pipe system for. the same service. Two-pipe systems may be divided into two classes, direct return sys tems (Fig, 1), and reversed return systems (Fig. 2). In a direct return system the water returns to -the heater by a direct route after it has passed through its radiator and, as a result, the paths through the three radiators shown in Fig. 1 are of unequal lengths, the path through the first radiator being the shortest and that through the third radiator, the longest. In a reversed return system, the water returns to the heater by an indirect route after it has passed through the radiators, so that the paths leading through the three radiators shown in Fig. 2 are practi cally of equal length. The reversed return system has an advantage over the. direct return . system in that it is more likely to function, satisfactorily even though the Chapter 33--Hot Water Heating Systems and Piping the velocity of the.water increases the cost of operating the circulating pump. There is an optimum velocity of the water in a heating system for which the sum of the cost of the system and the cost of its operation is a minimum. This velocity should be determined by calculation for the particular system under consideration, . Since the velocities in forced circulation systems are higher than those in gravity circulation systems, and since the friction heads in a heating system vary almost as. the squares of the velocities, a given error in the calculation or assumption of a velocity is less important in a forced circu lation system than in a gravity circulation system and, consequently, it Fig. 1. A Direct Return System Fig. 2. A Reversed Return System pipe system is not accurately designed. For example, if in Fig. 2 all pipes are of one size, each of the three radiators will receive approximately the same quantity of hot water because the three paths are practically of equal length, whereas in Fig. 1, if all pipes are of the same size, Radiator 1 will receive more water than the others because the path through it is shorter than those through the other radiators. As a result, Radiator 1 will be filled with water at a higher average temperature than -the re maining two radiators, and will therefore dissipate more heat. To. pre vent this unequal distribution of heat it is necessary to throttle the paths through Radiators 1 and 2 so that the friction heads of the three paths are equal when each radiator receives its proper quantity of water. A comparison of Fig. 1 arid Fig. 2 may suggest that a reversed return system requires considerably longer mains than a direct return system. This is not' always the case. For example, note the reversed return system of Fig. 3. PIPE SIZES The pressure heads available in forced circulation systems are much larger than those in gravity circulation- systems, consequently, higher velocities may be used in designing the system, with the result that smaller ' pipes may be selected and the first cost of the installation reduced. As the pipes of a heating system are reduced in size, the necessary increase in 588 Fig. 3. A Forced Circulation Reversed Return System3 "Note that the numbers on the radiators indicate thousands of Btu per hour (Mbh) and not square feet. is easier to design a satisfactory forced circulation system than a satis factory gravity circulation system.: . :. FORCED CIRCULATION The following examples will illustrate the procedure, to be. followed in designing forced circulation Systems: ' f L Assume that the longest path through 7radiators shown in Fig. 3 consist ot 2U0 It of mains, 25 ft of radiator connections, 1 boiler; 1 radiator, 1 radiator valve, 1 stop cock, 12 ells, and 2 tees. Also assume that the short branch main contains the same number of fittings and that the main is 150 ft long with 7 ft of radiator connections, design the piping for thig system. . . Solution. The friction heads of boiler, radiator valve and tee may be expressed in terms o[ the friction head in 1 elbow according to the values given in Table 1. Having done this, the longest circuit consists of 225 ft of pipe and 34 elbow equivalents. The inction head of 1 elbow is approximately equivalent to that in a pipe having a length ' equal to 25 diameters: Assume that the average pipe size, in this case will'be 1 in. ' 589"' " "- ' rictionF Head in M iuncneo per Foot o r Pipe of andAmerican Society Heating Ventilating Engineers Guide, 1936 590 Chapter 33--Hot Water Heating Systems and Piping Referring to Table 2, 1 elbow equivalent of 1 in. pipe is equal to 2.3 ft and the total equivalent length of the longest circuit is 299 ft of straight pipe. Similarly the equivalent length of the short branch is 231 ft. Having determined the equivalent pipe length, the next step is to assume the rate at which the water is to be circulated through the complete system. The water may flow through the radiator so that it will cool 10 or 20 F or any other reasonable number of degrees, but in this case, assume a temperature drop of 20 F through the radiation. One gallon of water per minute with a density of 7.99 lb per gal at 215 F will deliver approximately 9600 Btu per hour. The total radiation load is 85,000 Btu per hour (85 Mbh) and therefore the pump must circulate 4250 lb of water per hour or 8.85 gpm for a temperature drop of 20 F. Table 1. Elbow Equivalents3 ' 1 90-deg elbow.--........................................................................................................................... 1.0 1 45-deg elbow.--....................................................................... :.................................................. 0.7 1 90-deg long turn elbow._................................................................................ .......................... 0.5 1 open return bend--................................................................... ...................................................' '1.0 1 open gate valve........................................................................................ 0.5 1 open globe valve.................................................. _.................................................................... 12.0 1 angle radiatorvalve...................................................................................................................... 2.0 1 radiator-......................................................................................................................................... 3.0 1 heater................................................................................... ;............................................ ;............ 3.0 1 tee.................................................................................... (Noteb)* 1 2 The loss of head in one elbow can be expressed In terms of the velocity head by the formula: where h = the loss of head in feet, v =* the velocity of approach in feet per second, and 2g ** 64.4 ft per second per second. (1) bThe loss of head in tees when water is diverted at right angles through a branch of the tee varies with the per cent diverted. When the water diverted is less than 60 per cent of that approaching the tee, the loss of head, in elbow equivalents, may be expressed as follows: *. Ii' (2) where Aa = the loss of head in elbow equivalents, pi " the velocity of approach, p* = the velocity of water diverted at right angles. Values in elbow equivalents for the most common percentages of water diverted in a lxlxl-in. tee are as follows: ' 16.0 9.0 4.0 1.8 For other percentages the approximate values may be secured by interpolation. When the water la diverted from the tee into a smaller size branch, as in a lxlx%-in. tee, approximate values may be secured by means of Formula 2. The next step in the design is to assume the velocity at which the water is to circulate through the system which may vary materially. As the velocity is increased, the size of the pipes and the cost of the system are decreased, but the cost of operating the circulating pump is increased. The designing engineer should make a careful study to determine the velocity which will produce the most economical installation. With the equipment and piping now available, the most economical pipe velocity is one which will produce approximately a frictional loss of from 150 to 300 milinches per ft. In this case assume a frictional loss of 240 milinches per ft to be produced in the complete circuit of piping. Therefore 299 X 240 = 71,800 milinches or 6 ft static head required of the pump when circulating 8.85 gpm. ' . The pipe size may now be selected from Fig. 4 making allowance for the fact that the 2 circuits are of unequal lengths. Size the longest pipe circuit first. Section AB which is that portion of pipe connecting the boiler to the distributing main, must have a ca pacity of 85,000-Btu per hour (85 Mbh) and referring to Fig. 4, it will be noted that a lA in. pipe is slightly too large to carry the total load. Therefore a lfi in. pipe-may be satisfactorily selected for Sections AB and RI. The load branches at B with-28 Mbh in American Society of Heating and Ventilating Engineers Guide, 1936 branch BC and 57 in BJ. It will be noted that 28 Mbh is slightly over the capacity of a % in. pipe, therefore use a V in. pipe in BC and a 1 in. in Section HR. Section CD should have a capacity for 23 Mbh, therefore use a V in. pipe in CD and GH. A capacity of 20 Mbh is not sufficiently under the capacity of a V in. pipe to warrant the use of a V in. pipe, so use V in. in Sections DE and FG. The radiator branches are sized ac cordingly,with Vi in. up to 11,000 Btu (11 Mbh) and V in. up to 25,000 Btu (25 Mbh). Due to the difference in the equivalent lengths of each circuit, a static head of 6 in. on the pump would produce a greater velocity in the shortest branch than in the longer branch and consequently a higher friction loss per ft. This variation is usually a negligi ble factor in most installations and can usually be overlooked. Should the variation in friction head be sufficient to allow the use of smaller pipes, this factor should be taken into consideration. For purposes of illustration in this example, assume that Section AB is 4 ft, and then 4 X 240 = 960 milinches. 71,800 -- 960 = 70,840 milinches. 70,840 divided by 231 (total equivalent length of short branch) = 306 milinches per ft which is ' 66 milinches per ft more than is available in the longer circuit. Therefore approximately 12 per cent more capacity is available in the pipes which will change the pipe size only a slight amount. If it is necessary to correct this variation, generally a stop cock may be placed in the return line of the short branch and adjusted after complete installation. However, if the variation be of sufficient magnitude, the pipes in the shorter branch should be sized accordingly. In this case the pipe size should be selected according to a frictional loss of 240 milinches per ft. Due to the fact that Section BJ requires a capacity of 57 Mbh, which is slightly over 1 in., use a 1 in. pipe in BJ and QR. Section JK has a Table 2. Capacities of Pipes in Mbh (1000 Btu per Hour) and Velocities of Water, in Pipes in Inches, per Second for Forced Circulation Systems with a Total Friction Head of 2 ft and for a Maximum Temperature Drop of 10 Fa 1 ' Pipe ' - Size (Inches) 2 Equivalent Length op Pipe (FEBTb) ' 63 4 5 7 89 Equivalent Total Length op Pipe in Feet in Longest Circuit 100 , 150 200 250 300- 350 Unit Friction Head, in Milinches ` 400' . 240 160 120 96 80 69 60 V i IV i.H 2 m 1 2' 2.3 3.0 3.5 4.0 '6:0 6.2 15 13.2 18 26.0 22 52.8 27 79:2 30 158.8 36 250.0 41 4.8 . 4-J 12 10 .3.4 9 10.3 14 8.6 ' - 7.3 12 11 19.2 16.3 - U:4 17 . 15 1? 40.8 34.8 . 31 .2 21 v18- 16 60.7 23 51.2 20 46.6 18 120:0 104.0 28 24 93.5 22 192.0 164-5 149.0 32 28 25 2.9 8. 6.2 10 12.5 12 27.8 15 40.8 16 86.4 20 139.2 22 2.6 7.5 6.0 9 12.0 11 26.4 14 40.0 15 81.6 18 135.8 21 2.4 7 5.5 8.5 11.1 10,5 24.0 13 36.0 14 73.8 17 122.5 19 3 6.5 444-0 348.0 294-0 270.0 254.0 240.0 223.0 48 37 32 29 26 24 22 For other temperature drops the capacities of pipes are to be changed correspondingly. For example, for a temperature drop'of 30 F, the capacities shown in this table are to be multiplied by 3. The velocities- remain unchanged.- . . . . . ^Approximate length of pipe in feet equivalent to one elbow in friction head. This value varies with the velocity. . 592 Chapter 33--Hot Water Heating Systems and Piping load of 47 Mbh which is approximately 1 in. Therefore use 1 in. in JK and PQ. KL carries 35 Mbh which is approximately half-way between V and 1 in. Use % in. in KL and 1 in. in OP. Section LM requires a capacity of 20 Mbh, therefore use V in. in LM and NO. Size radiator branches as previously described. .; Many times a Vi in. pipe will prove to be too large, but at the present time there seems to be a slight aversion in practice against the use of pipes of smaller sizes, especially for hot water installations. If a number of heating systems are to be designed for similar conditions, i.e., for a total friction head of 6 ft and a temperature drop through the radiators of 20 F when the maximum quantity of heat is being delivered to the building, a table such as Table 3 may be prepared from the data of Fig. 4. Having this table, the pipe sizes for the system of Example 1 can be easily selected: For example, for Sections AB and i?/, each supplying 85 Mbh, the equivalent pipe length of the system is 299 ft. In the table the length shown nearest to this length is 300 ft,. In the 300-ft column, a 1-in, pipe is too small and a lj^-in. pipe is too large. The lj^-in. pipe will therefore be selected. For other systems, it will be economical to operate with different friction heads, and tables may be prepared similar to Tables 2 and 4, which are based on total friction heads of 2 and 18 ft, respectively. ... Table 3. Capacities of Pipes in Mbh (1000 Btu per Hour), and Velocities of Water in Pipes in Inches per. Second for Forced Circulation Systems with a Total Friction Head of 6 ft and for a Maximum Temperature Drop, of 10 Fa 1; . 2 3: 4: 5- | 6 r 18 Pipe Size (Inches) . Equivalent Total Length op Pipe in Feet in Longest Circuit Equivalent Length or Pipe (Febt*>) 200 | 300 | 400 | 000 800 |...1000 . .Unit Friction Head, in Milinches . 360 240 : . iso 120 90 72 V' 1 7.4 18 6.0. 15 : 5.0 13 3.8 : 10 3.4 S.l 9 7.5 V 1 IV' 2 2.5 3.3 15.8 22 80.0 27 64.8 33 12.7 j 18 ' 24.0 22 52.51 26 10,8 16 20.4 19 44-4 23 8-4 l 12 15.8 : 15 83.6 18 7.7 11 13.9 13 30.0 . 16 6.7 9 12.5 11 26.8 14 iv 4.0 2 . 5.0 96.0 37 192.0 44 76.8 31 153.0: 36 64.8 26 130:0 30 50.1 20 .100.1 24 44-7 18 90.0 21 40.8 15 78.0 18 IV 6.0 300.0 244.0 206.0 161.0 144-0 . 130.0 50 41 35 26 24 21 3 7.5 550.0 436.0 368.0 287.0 249.0 228.0 42 .. 32 27 24 fy.tempeptuw^^ 30 fT the ca^dUeeaho^taStable the*velodty*aiate plpe ln fet equivalent to one elbow In friction head. This value variesVith 593 - "' of andAmerican Society Heating Ventilating Engineers Guide, 1936 Example 2. Design a direct return two-pipe forced circulation system for the layout shown in Fig. 5 assuming a temperature drop of 10 F through the radiation. For this system the length of the pipe line from the boiler to the highest radiator on the farthest . riser and back to the boiler is about 250 ft. There are about 16 elbow equivalents hav ing an equivalent pipe length of about 50 ft, so the total equivalent pipe length is about 300 ft. Solution. The same pipe size tables may be used as those developed for the reversed return system of Fig. 3, Table 3 which provides for a friction head of 6 ft. . Referring to the column for an equivalent total length of 300 ft for Sections AB and KA, each supplying 117.6 Mbh, it will be found that a l^g-in. pipe is too small and a 2-in. pipe is too large. Consequently, a lK-in. pipe is selected for the flow line AB, and a 2-in. pipe for the return line KA. For Sections BC and /IT, each supplying 88 Mbh, a lH-iu- pipe is only slightly too small and it is selected. The remaining pipe sizes are selected in a similar manner and recorded in Fig. 5. For a temperature drop of 10 F, 24.5 gpm of water must be circulated. The pump to select is one which has its highest efficiency when it is delivering 24.5 gpm against a 6-ft head. To secure a correct distribution of hot water among the several risers it is necessary, as previously stated, to introduce special resistances to balance the several risers, as follows: The first riser is 80 ft nearer the boiler than the fifth riser. In order that the two may be balanced, t.e., that they may operate under equal pressure heads, resistance must be added to the first riser equal to the friction head in the 80 ft of flow main from B to F plus that in the 80 ft of return main from G to K. . Table 4. MbhCapacities of Pipes in (1000 Btu per Hour) and Velocities of Water in Pipes in Inches per Second for Forced Circulation Systems with a Total Friction Head of 18 ft and for a Maximum Temperature Drop of 10 Fa 1 2 ' 3 1 * 1 '3 1 4 1 7 Equivalent Total Length op Pm nr Feet in Longest Circuit ' Pin 8m (Inches) Equivalent Length or Pipe (Feet*>) 200 1080 400 600 800 Unit Friction Head, in Milinches 540 360 . 270 1000 216 k 1.0 12.7 32 8.6 23 7.2 18 6.2 15 5.5 13 X 2.0 27.5 40 18.7 28 15.1 22 18.7 19 11.5 17 l 2.5 55.0 86.8 80.0 26.4 22.6 48 34 > 27 23 20 IK 3.0 128.0 - 59 .81.5 42 66.0 33 ' 58.8 28 . 60.5 25 IK 4.0 182.0 122.0 98.2 86.2 74-2 66 46 37 31 27 2 5.0 871.0 252.0- 201.0 180.0 151.0 80 56 45 38 33 2K 7.0 . 598.0 91 407.0 65 828.0 51 287.0 43 240.0 38 3 9.0 1110.0 107 790.0 76 598.0 . . 60 " 527.0 51 448.0 44 a*or outer temperature uiups me vupouucb u< pipn TM w for a temperature drop of 30 F, the capacities shown in this table are to be multiplied by 3. The velocities remain unchanged. . .. ^Approximate length of pipe in feet equivalent to one elbow in friction head. This value vanes with the velocity. 594 Chapter 33--Hot Water Heating Systems and Piping It will be noted from Table 3 that the unit friction head is about 240 milinches per foot The total friction head in the flow and return mains between the first and fifth risers is'therefore 160 X 240 or 38,400 milinches, or a little more than 3 ft, which must be supplied by additional resistance in the first riser to prevent its having an advantage over the fifth riser. This resistance can be supplied by a calibrated and adjusted modulating valve or by an orifice resistor in a union. If the orifice resistor is to be used, its size may be selected from Table 5 as follows: The lower part of the first flow riser supplies 28.8 Mbh. According to Table 3, it should be a 1-in. pipe and would have a velocity of 22 in. per second, if it were supplying 24 Mbh. Since it is supplying 28.8 Mbh, the velocity will be about 26 in. per seconds From Table 5 it will be found that for a 1-in. pipe and a velocity of 24 in. per second; an 0 45-in. orifice will produce a loss of head of 37,000 milinches. For a velocity of 26 in.'1 per second, the loss of head will be somewhat more, probably about 43,000 milinches; the difference between it and the required resistance will be about 10 per cent, which is per missible, and the 0.45-in. orifice is selected. ' The sizes of the orifice resistors for the second, third, and fourth risers are selected in a similar manner and found to be 0.45 in., 0.50 in., and 0.55 in., respectively. If the design of the system of Fig. 5 is to be extremely refined, the gravity pressure heads produced by the risers should be taken into con sideration. With water at 220 F and 210 F, respectively, in the risers, the gravity head is 50 milinches per foot of waiter column or-25 milinches per foot of flow and return pipe. The pump pressure head in this case is 240 milinches per foot of pipe, and the gravity head, being only one tenth as large as the pump head, may be neglected without serious error. This is generally done. ". Temperatures of 220 F and 210 F would be used only during the coldest weather for which the system is designed. At other times the tempera tures would be lower, the temperature drop smaller, and the gravity heads smaller. The pump pressure head remains constant throughout the season if the pump is operated at a constant speed and, consequently, the gravity head is generally less than one-tenth of the pump head. Effect of Variations in Pipe Sizes The pipe sizes for the several parts of the system selected from the tables are only approximately correct but the resulting, error should be . 595 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Table 5. Friction Heads (in Milinches) of Central Circular . Diaphragm Orifices in Unions Diameter or Orifices (Inches)' 2| 3 Velocitt or Water in Pipe in Inches per Second 4| 6 |8 | 10 | 12 18 | 24 %-in. Pipe ' 36 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 5700 2900 1500 740 350 170 20,800 10,400 5200 2600 1300 620 300 32,000 16,000 8000 4000 2000 970 480 45,000 23,000 12,000 6800 2900 1400 700 57,000 26,000 13,000 6500 3200 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 4000 . 2300 1400 750 440 260 14,000 7200 4100 2300 1300 800 460 22,000 12,000 6400 3700 2200 1300 720 32,000 17,000 9300 5400 3000 1800 1100 37,000 21,000 12,000 7000 4200 2400 ^. 65,000 37,000 22,000 50,000 13,000 28,000 7400 17,000 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 1%-in. Pipe 8900 5800 3800 2500 1700 1150 750 16,000 10,400 6800 4400 3000 2000 1300 25,000 16,400 10,500 6900 4700 3100 2100 36,000 23,000 15,000 10,000 6700 4500 3000 53,000 34,000 22,000 15,000 10,000 6700 60,000 40,000 27,000 60,000 18,000 40,000 12,000 26,000 . 1%-in. Pipe ' 0.55 0.60 0.65 0.70 . 0.75 0.80 0.85 850 1900 600 1300 400 : 850 260 600 180 400 300 200 3300 2300 1500 1100 760 540 . 380 7400 5400 3600 2600 1800 1200 860 13,000 8600 7200 4400 3000 ' 2200 1600 21,000 16,800 10,400 7000 5000 3200 2300- 30,000 21,000 14,000 10,000 7000 5000 3000 -v 2-in. Pipe 50,000 30,000 21,000 14,000 10,200 7800 53,000 39,000 28,000 19,000 45,000 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 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 38,000 23,000 14,000 8100 4400 Nde.--The losses of head for the orifices in the lM-in. and 2-in. pipe were calculated from those m the smaller pipes, the calculations being based on the assumption that, for any given velocity, the loss of head is a function of the ratio of the diameter of the pipe to that of the onfice. This had been found to be practically true in the tests to determine the losses of head in orifices m Ji-m-, 1-in., imd Ui-U- P'P*. ">n" ducted by the Texas Engineering Experiment Station, and also in the tests to. determine the losses ot head in orifices in Ms, 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). 596 Chapter. 33--Hot Water Heating Systems and Piping negligible as may be seen from the following study. Assume, as an extreme case, that the error in pipe size is so large that the water flows twice as fast through one of the radiators as through the others. This would make the friction head through this radiator almost four times as large as those through the other radiators. The result would be that the water, in flowing through the radiator, would cool 5 F instead of 10 F. The mean water temperature in the radiator would then be 2173^ F in stead of 215 F, and the mean temperature difference, water to air, would be 147J4 F instead of 145 F. The heat dissipated by the radiator would . therefore be about 2 per cent more than calculated. It is evident that this difference in heat dissipation is smaller than the difference between Fig. 6. A One-Pipe Gravity Circulation System Fig. 7. A Two-Pipe Direct Return Gravity Circulation System the calculated heat losses and the actual heat losses, and also smaller than the average difference between the calculated radiator sizes and the nearest stock sizes selected. '- GRAVITY CIRCULATION For gravity circulation,' the one-pipe system shown in Fig. 6 aiid the two-pipe direct return system shown in Fig. 7 are probably in most common use: . ' The one-pipe system has the disadvantage that the radiator nearest the . 597 i American Society of Heating and Ventilating Engineers Guide, 1936 boiler is the only one which receives water at approximately the tem perature at which it leaves the boiler. All other radiators receive cooler water and must be proportionally increased in size, so the total heating surface in the system is considerably larger than that in a corresponding two-pipe system. The pipe sizes in gravity circulation systems may be varied. As the .pipe sizes are decreased, the temperature drop through the radiators, which produces circulation, is increased and it becomes necessary to increase the temperature of the water leaving the boiler so that the mean temperature in the radiator remains constant. For example, Fig. 8 shows diagrammatically an elementary heating system which will function with either 134-in. or 1-in. pipe. The radiator is required to deliver 27 Mbh, and the circuit consists of 30 ft of pipe and .20 elbow equivalents. If 1 }4-in. pipe is used, the system will operate correctly if the water temperatures in the flow and return risers are 200 F and 180 F, respectively. The mean water temperature in the radiators will then be 190 F and, if the radiator is located in air having a temperature of 70 F, the size of the radiator must be sufficient to deliver 27. Mbh under these conditions. r _HcitTc* Fig. 8. An Elementary System If 1-in. pipe is used, the system will function correctly with water tem peratures in the flow and return risers of 210 F and 170 F, or of 200 F and 160 F. In the. first case, the mean water temperature is again 190 F and the same, size radiator may be used as with the 134-in. pipe, but the temperature of the water leaving the boiler must be raised from 200 F to 210-F. In the second case, the temperature of the water leaving the boiler is the same as for the 134-in- pipe, but the mean water temperature in the radiator is lowered from 190 F to 180 F, and theoretically the size of the radiator should be increased about 1234 Per cent to deliver the required 27 Mbh (See Table 3, Chapter\6, 1933 Guide). This indicates the extent to which pipe sizes arid radiator sizes may be decreased by increasing the temperatures of the water in the boiler, as is possible in closed systems and in open systems in which the open expansion tank is located sufficiently high to secure a pressure in the boiler equal to that existing in the boiler of the closed system. Example 3. Design a one-pipe gravity circulation system for the layout shown in Fig. 6. Assume that the main circuit consists of 150 ft of pipe, 7 elbows, and one boiler. Solution. Replace the boiler by 3 elbow equivalents and assume that the size of the main will be about 2 in. According to Table 6, Column 2, a 2-in. elbow is equivalent to 4 ft of pipe, and the total equivalent length of the main will be about 150 plus 40, or 190 ft. Assuming that the center of the boiler will be about 4 ft lower than the horizontal portion of the main and that the temperature drop in the system is to be 35 F, Table 6 may be used to determine the size of the mains. Note from Column 8, for a 200-ft 598 Chapter 33--Hot Water Heating Systems and Piping Table 6. Capacities of Mains in Mbh, for One-Pipe and for Two-Pipe Direct ' Return Gravity Circulation Systems with a Total Friction Head ' of 0.6 In., a Temperature Drop of 35 F, when the Mains are 4 Ft Above the Center of the Boiler 11 2 1314 5 6 7 1819 10 l U Pipe Size (Inches) Equivalent Length or Pipe (Feeto) Equivalent Total Length or Pipe in Feet m Longest Circuit 75 | 100 125 150 175 200 250 : 300 1 350 Unit Friction Head, m Miunchee 8.0 6.0 4.8 4.0 3.4 3.0 2,4 zo 1.7 136 3.0 43.0 37.5 33.0 30.0 87.0 85.0 88.8 80S 18.7 2 4.0 83.0 78.0 63.0 67.0 61.0 .48.0 48.0 38.0 35.0 236 4.5 140.0 115.0 100.0 90.0 81.6 75.4 67.8 61.0 56.0 3 5.0 834-0 804.0 176.6 160.0 143.0 133.0 110.0 107.5 100.0 336 5.5 347.0 300.0 860.0 836.0 814.0 800.0 177.0 160.0 146.0 4 ' 6.0 490.0 '488.0 370.0 334.0 897.0 878.0 848.0 883.0 805.0 "Approximate length of pipe in feet equivalent to one elbow in friction head. This value varies with the velocity. length, that a 2-in. mam will supply 48 Mbh and a 236-in. main, 75.4 Mbh. Since the system to be designed is to supply 66 Mbh, a 2-in. pipe is too small and a 23'6-in. pipe too large. The solution is to use some 2-in. and some 236-in. pipe. Since the 236-in is nearer the correct size than the 2-in., select 2-in. pipe for the first 50 or 60 ft out of the boiler and 2j4-m. for the remaining pipe back to the boiler. Tables 7 and 8 may be used to design the radiator risers and connections. According to Table 7 for 12 Mbh the flow riser should be % in. and the return riser 1 in., and the riser branches should be 1 in. and 134 in., respectively. Note that according to Table 8, both radiator tappings should be 1 in. To simplify the construction, select 1-in. flow Table 7. Maximum Capacities of Risers3 in Mbh, and Velocities of Water in Pipes in Inches Per Second for One-Pipe and for Two-Pipe Direct Return Gravity Circulation Systems with a Drop of 35 F Through Each Radiator , Pipe Sizb (Inches) Flow Returo or Pipe (Fhctc) . 1st Floor!) Vet (Iq. per SecJd Mbh Flow Return 2nd Floor Mbh 3rd and 4th Floors Mbh 36 36 1.0 6 6.8 36 34 6-4 8.0 34 34 1.5 9 2.3 2.3 10.1 14.0 34 1 11 1 134 2.0 18 3.2 2.0 18 2.5 2.5 81 3.0 2.0 18.8 80 85.8 17.1 86.0 84 134 134 3.0 86 3.0 3.0 43 55 134 136 34 4.0 2.5 136 136 3.5 48 3.0 3.0 third and fnurt'h iw "1PTM", he"? ?! 4S?' I800;3150. and 4500. respectively, for the first, second, nectinn. -3 ra?lat?rB' ?,nd n faction heads of 200 miUnches for the first floor radiators and con- a d 700 millnche3 for Ml other radiators and their connections risers " nSer branches-the pipinS which connects the risers to the mains, are to be one size larger than the the wbdt^imate lenEth f PiPeS `n fKt equivalent to ne dbow in friction head. This value varies with ^Velocities apply to the riser branches. 599 American Society of Heating and Ventilating Engineers Guide, 1936 risers with 1-in. riser branches and 1-in. radiator tappings. Also select lM-in. return risers with 134-iu. riser branches, and 1 14-in. radiator tappings. Similarly, for 18 Mbh, select lJ4-in. flow and return risers and riser branches, and 1 M-in. radiator tappings. To develop a rule for determining radiator sizes, assume a system similar to that of Fig. 6, in which the total temperature drop is to be 35 F and which is equipped with 7 radiators, all radiators dissipating equal quantities of heat. The mean temperature of the water in the radiators will be reduced 5 F for each successive radiator. If the mean tempera ture of the water in the first radiator is 200 F, the mean temperature of the water in the seventh radiator will be 170 F, and, according to Table 3, Chapter 6, of the 1933 Guide, the heat dissipation of these two radiators will be to each other as 868 is to 617, or as 140 is to 100, and therefore if the last radiator is to dissipate as much heat as the first, its size must be 40 per cent larger. Example 4- Design a two-pipe, direct return, gravity circulation system (or the lay out shown in Fig. 7. Assume that the main circuit from the boiler to the farthest flow riser and from the farthest return riser back to the boiler consists of 160 ft of pipe, 6 elbows, and 1 boiler. ; Table 8. Maximum Capacities of Radiator Connections in Mbh, for One-Pipe and for' Two-Pipe Direct Return Gravity Circulation Systems with a Temperature Drop of 35 F Through Each Radiator Pips Size Flow Return.' Equivalent Length . op Pipe (Feet) 1st Floor ' ' Mbh . 2nd, 3rd, and 4th Floors Mbh ' 34 34 kK KK Kl ll l. IK IK i K 1.0 1.5 2.0 3.0 4-1 5.2 7.0 9.1 12.6 17.6 2S.S 6.9 7.6 10.5 ' 1S.0 . 17.8 23.2 S3.2 Che velocity. Solution. Replacing the boiler by 3 elbow equivalents and assuming that the largest size of the main! will be about 3 in., the total equivalent length of the main will be 160 plus 45, or 205 ft. Assuming that the center of the boiler will be about 4 ft lower than the horizontal portion of the main, and that the temperature drop will be 35 F for the system, the pressure head caused by the difference in weight between the water in the flow and return risers joining the mains to the boiler will be about 0.6 in. of water, or about one-fortieth of the pressure head produced1 by the circulating pump selected for the system of Fig. 3. . Table 6 may be used to determine the size of the main as follows: Refer to Column 8 and note that for Sections AS and IA, which supply 105.6 Mbh, a 3-in. pipe is too large and a 2pipe is too small; hence, select 234 in. for Section AB and 3 in. for Section IA. For Sections BC and HI, which supply 76.8 Mbh, a 234-in. pipe is almost exactly the correct size and is selected for both sections. . For the forced circulation system of Fig. 5, the pressure head produced by. the circu lating pump is used to force the water through the mains and also through the risers. Gravity circulation systems have two distinct pressure heads. One is produced by the difference in weight of the water in the flow and return risers adjacent to the boiler, and is the boiler pressure head, which in this case is 0.6 in. The other pressure head is pro - duced by the difference in weight of the water in the flow and return risers adjacent to the radiators, and is the radiator pressure head. If the temperature drop through the radiators is about 35 F, and if the story heights of the building are 9 ft and the distance from the center of the first floor radiator to the average level of the main is 3 ft, the 600 Chapter 33--Hot Water Heating Systems and Piping radiator pressure head of the first floor radiator is about 450 milinches and the pressure heads of the radiators on the upper floor are 1350 milinches greater than those on the next lower floors. Tables 6 and 7 are based on the assumption that the boiler pressure head must be equal to the friction head in the mains, and that the several radiator pressure heads must be equal to the respective radiator and riser friction heads. To design the radiator risers, use Table 7 and begin with the set nearest the boiler. The first floor risers must supply 28.8 Mbh. According to the table, lK-in. flow and return risers will supply 26.0 Mbh; if the return riser is increased to 134 in., the capacity will be increased to 34.0 Mbh. This is considerably larger than necessary, and 134-in. flow and return risers are selected. However, it must be remembered that the riser branches, which are the connections from the flow and return mains to the flow and return risers, are to be one size larger than the risers. The second floor risers must supply 19.2 Mbh. According to the table, the capacity of 1-in. flow and return risers is 20.0 Mbh, and that size is selected. The third floor risers must supply 9.6 Mbh. If a 34-in. flow and a %-in. return riser are used, the capacity will be 8.0 Mbh; if both risers are K in., the capacity will be 14.0 Mbh. The pipe is selected for both risers. ; , ... , To design the radiator connections, use Table 8 and note that for the first floor radiator connections the capacity of a M-in. flow and 1-in. return is 9.1 Mbh, and that of a 1-in. flow and a 1-in. return is 12.5 Mbh. The former is more nearly the correct size, but since it is difficult to secure a good flow through first floor radiators, the 1-in. flow and return connection is selected. For the two upper floors, the capacity of a K-in. flow and return connection is 10.5 Mbh, and that size is used. As explained in the design of the forced circulation system of Fig. 5, the two-pipe direct return system of Fig. 7 will not function correctly unless its four sets of risers are balanced among themselves. This.neces sary balancing is accomplished by adding resistances to all. risers, except the one farthest from the boiler, equal to the excess boiler pressure heads available for those risers above the boiler pressure head available for the farthest riser. For example, the first set of risers is 60 ft nearer the boiler than the last set. Since the flow and return mains are designed for a friction head of 3 milinches per foot (See Table 6, Column 8), the boiler pressure head available for the first set of risers is 360 milinches in excess of that available for the fourth set. The velocity in the riser branch is 3 in. per second (See Table 7) and, therefore, according to Table 5, an 0.65-in. orifice in a lj^-in. union should be used. This will provide a resistance of about 420 milinches. In the same manner it is found that for the second set of risers a resistance of 240 milinches is required and that an 0.70-in. orifice in a 1 J^-in. union will provide a resistance of 285 milinches. For the third set of risers, a resistance of 120 milinches is required and an 0.60-in. orifice in a 1-in. union will provide sufficient resistance. MECHANICAL CIRCULATION Circulating pumps for hot water systems may be used to provide the motive head for forced circulation systems as already described, or to improve the operation of gravity-designed systems. Small speciallydesigned centrifugal pumps installed on a by-pass with the necessary gate or check valves near the point where the return main enters the heater may be employed. Specially-designed, electrically-driven, propeller-type circulating pumps or units may also be employed. The latter are usu ally installed directly in the return main and are available for all com mercial pipe sizes used for hot water heating. The motpr switch may be under manual control, automatic control using thermostatic elements, i 601 of andAmerican Society Heating Ventilating Engineers Guide, 1936 or tied in with the oil or gas burner switch which starts and stops the burner. For large capacities these units may be installed in multiple. For exceptionally large installations such as central heating plants, cir culating pumps of the centrifugal single stage type, having an average operating efficiency of 70 per cent against heads up to 125 ft, are some times used. It is generally advisable to install the pumps in duplicate to provide for contingencies and to insure continuous operation. In such cases each pump should be made equal to the maximum capacity required. EXPANSION TANKS When water at ordinary temperatures is heated or cooled, its volume is increased or decreased. This variation in the volume of the water in a heating system is generally provided for by means of an expansion tank into which the water can flow from the system during the heating-up periods and from which it can flow back into the system during the cooling-down periods. Fig. 9. An Open Expansion Tank Fig. 10. A Closed Expansion Tank . The expansion tank may be open or closed. In an open expansion tank (Fig. 9), the water is subjected to atmospheric pressure and can expand freely without a material increase in pressure. In a closed expansion tank (Fig. 10), the water is subjected to, the pressure of the compressed air within the tank, and as the water expands, the volume of the air in the tank is decreased and its pressure increased. The open expansion tank must be placed at a sufficient elevation above the highest radiator to prevent boiling when the water in that radiator is at the highest temperature to which it is to be heated. For example, if the water is to be heated to 225 F on extremely cold days, the absolute pressure on the water in the highest radiator must be at least 19 lb per square inch. This pressure will be secured if the open expansion tank is located 15 ft above the highest radiator. If a closed expansion tank is used and is located 30 ft below the highest radiator, an absolute pressure of about 32 lb per square inch must be maintained in the expansion tank if the water in the highest radiator is to be heated to 225 F without danger of boiling. 602 Chapter 33--Hot Water Heating Systems and Piping The type of expansion tank used in a heating system, whether open or closed, has no influence on the operation of the system. The only function performed by the expansion tank is to provide for the variation in the volume of the water in the system, and at the same time to maintain a sufficient pressure in the system to prevent boiling when the water is at the highest temperature for which the system is designed. The use of an expansion tank may be dispensed with when the heating system is allowed to float on the water system, i.e., when the connection between the heating system and the water system is kept open so that the water system replaces the: expansion tank. The capacity of the expansion tank should be at least twice the in crease in volume produced when the water in the system is heated from its normal to its maximum temperature. When 25 gal of water are heated from 40 F to 200 F, the volume of water increases to 26 gal. A safe rule, therefore, is to make the water capacity of the expansion tank equal to 10 per cent of the capacity of the heating system. In a forced circulation system, the expansion tank should be connected to the return main near the circulating pump. In a gravity circulation system, the expansion tank should be connected to the flow riser so that air liberated from the water in the.boiler may escape through the ex pansion tank, except where it is desired to maintain a temperature higher than 212 F, in which.case the connection should be in the return main to prevent possible boiling in the expansion tank. The expansion tank should be protected so that the water in the tank or in the connecting pipe lines cannot freeze. If such water should freeze and the water in the system be heated to cause further expansion, the resulting force will burst the boiler or some other portion of the system. INSTALLATION DETAILS The detailed installation of the pipe system should be governed by four fundamental rules: . 1. All piping must be pitched either up or down so that all gases which are liberated from the water can move freely to a vented section of the system. Whenever practicable, the pipe line should be pitched so that gases flowing to a vent will flow in the same direc tion as the water. When a pipe system cannot be installed without creating air pockets, that is, sections in the system from, which liberated gases cannot escape, such sections must be provided with automatic air relief valves or with air valves which may be operated manually when necessary, or trapped into a pressure tank. 2. .All piping must be arranged so that the entire system can be drained, either to permit alterations or repairs, or to prevent freezing if the system is not to be operated during a cold period. It is well to install a gate valve and union in every riser near the main to permit the draining of individual risers without draining the entire system. It is also well, in large installations, to divide the system into branches and to provide each branch with unions and valves so that any one branch can be drained without disturbing the remaining ones. ------- .u..,6 ucaiing oysienis into uranenes or zones ana providing each zone with individual valves has the further advantage of permitting a varying temperature control. For example, if a building is equipped with a forced circulating system and if the south rooms are on one branch of the main and the north rooms are on a separate branch, the valves may be set so that the water will circulate through the north branch with a temperature drop of, say, 10 F, and through the south branch with a tempera ture drop of, say, 20 F, thus delivering less heat to the south rooms than to-the north 603 American Society of Heating and VENTiLATiNG Engineers Guide, 1936 rooms. This arrangement is especially valuable when the regulating valves are controlled thermostatically by the temperatures in the two zones, because no matter how accurately the heating system may have been designed, the heat demand of any group of rooms varies with sunshine and with wind velocity, and these intermittent variations can be provided for only by the individual control made possible by changing the valve settings controlling the heat supplied to particular groups of rooms. 3. 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. 4. The pipe system must be installed so that each circuit has its correct friction head. To bring this about, it is necessary in some cases to minimize the friction, to make the pipe line as short as possible and to provide as few fittings as possible; and in other cases it is necessary to increase the length of the pipe and the number of fittings so that, for every circuit, the friction head will be equal to the available pressure head. The connections from the boiler to the mains should be short and direct, to reduce the friction head. It is frequently possible to avoid an elbow and to reduce the length of the ; ' Fig. 11. Method of Connecting Radiator to Allow for Expansion of Pipe pipe by running the pipe in a diagonal direction, either in a horizontal or in a vertical plane. The mains and branches should pitch up and away from the heater, generally not less than 1 in. in 10 ft. The flow main should always be covered; the return main should be covered except where it is to provide the heating surface for the basement. The connections from mains to branches and to risers should be such that circulation 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 correctlydesigned 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 connections from the heater is not material; but it is generally best to'have the two connections about equally distant from the heater. In some cases it may be advisable to take the flow connection off the top of the main and the return connection from the side, but in most cases both connections should be at an angle of 45 deg, This method shortens the lines and substitutes 45-deg ells for 90-deg ells. Preferably, connection of the flow riser to a radiator should be to the upper tapping, and connection of the return riser to a radiator should be to the lower tapping. When hot water enters at the top of a radiator it will distribute itself along the entire length of the radiator, and as it cools it will settle gradually to the bottom; the cool water may then be taken out of the radiator at either end. With forced circulation and high velocities, it is advisable to let the water enter at the top of the radiator and leave at the bottom of the opposite end. With gravity circulation and low velocities it makes little difference whether the water leaves at the end at which it enters or at the opposite end. 604 - The connections of the risers to the radiators should be such that provision is made for the vertical expansion of the risers. This can be accomplished as indicated in Fig. 11 by using one tee and two ells for each connection. These connections should be pitched upward or downward, whichever may be necessary to prevent the formation of air pockets and to permit draining. PROBLEMS IX PRACTICE j 0 Will altering a hot water heating system from an open to closed type system (a) increase the circulation and (b) give more heat? . a. No. Tests conducted by the A.S.H.V.E. indicate that there is little, if any difference in the circulation when the system is under pressure. The difference in temperature between the supply and return, and the friction are the governing factors. b. With a closed system the water may be carried at a higher temperature without boiling which permits warmer radiators. . 2 What tends to prevent or to retard the circulation of water in hot water, heating systems? In both gravity flow and forced circulation systems, the friction which must be overcome when the water is flowing through pipes, fittings, valves, heaters, and radiators tends to prevent or retard circulation. For a given pipe the friction varies approximately as the 1.7 power of the velocity, and for given fittings, valves, heaters, and radiators, the friction varies approximately as the square of the velocity. It is therefore sufficiently accurate to express the friction in fittings, valves, heaters, and radiators in terms of the friction in one standard elbow, as shown in Table 1. 3 In the elementary heating system. Fig. 8, what is the pressure head main taining the circulation if the water in the return riser is at 180 F and that in the flow riser is at 200 F? It is found, from Table 7, Chapter 1, that 180 F water weighs 60.61 lb per cu ft and 200 F water weighs 60.13 lb per cu ft. The pressure head is independent of the size of the pipe. If the two risers were each 1 ft square, the water in the flow riser would weigh 601.3 lb and that in the return riser would weigh 606.1 lb. Thus the water in the return riser would weigh 4.8 lb more than that in the flow riser. Consequently, the resulting pressure head is 4.8 lb per square foot. Pressure heads are generally expressed in feet, or inches, or milinches of water of a given temperature. In this case we are dealing with water at both 180 F and 200 F, So the pressure head is expressed in terms of 190 F water. Such water weighs 60.39 lb percu ft, and to secure a pressure of 4.8 lb per square foot, it is necessary to have a column of water having a weight of 4.8 divided by 60.39 = 0.0795 ft, or 0.9540 in., or 954 milinches. . This is the pressure head which maintains the circulation. 4 In the elementary system of Question 3, if the radiator dissipates 14,000 Btu per hour, what is the velocity of the water in the pipe line, if the pipes are 1 in. in diameter? What, if they are % in. in diameter? Since the temperature drop through the radiator is from 200 F to 180 F or 20 F, every pound of water flowing through the radiators delivers 20 Btu; consequently, 14,000 divided by 20 = 700 lb of water, or for 190 F water, 700 divided by 60.39 = 11.59 cu ft of water must flow through the radiator and through the pipe lines every hour. The interior area of a 1-in. pipe is 0.864 sq in. The velocity in the 1-in. pipe is 11.59 divided by 0.864 and multiplied by 144 = 1932 ft per hour or 6.44 in. per second. For M-in. pipe, the interior area is 0.533, and the velocity is 6.44 multiplied by 0;864 and divided by 533 = 10.44 in. per second. . 5 If, in the elementary heating system of Question 3, a i-in. pipe line is used, what would be the friction head? 605 w of and 1936American Society Heating Ventilating Engineers Guide, If the radiator is connected as shown in Fig. 11, with the heater connected to provide freedom of expansion, the heating circuit may be assumed to consist of a heater, 25 ft of pipe, 8 elbows, 1 radiator valve, and 1 radiator. From Table 1 it appears that the heater and radiator are equivalent, in friction, to 6 elbows; hence, the circuit may be placed equal to 25 ft of pipe and 14 elbows. From the diagram of Fig. 4 it appears that the friction head for a 1-in. pipe and a velocity of 6.44 in. per second is about 25 milinches per foot. For 25 ft of pipe, the friction head will be 625 milinches. . .' v* It appears from Table 1 that the friction head in one elbow is , or in this case 0.54 multiplied by 0.54 and divided by 64.4 = 0.0045 ft or 54 milinches. Hence, for the 14 elbows the friction is 756 milinches. For the entire circuit, the friction head is the sum of the 625 milinches of the pipe plus the 756 milinches of the elbows, or 1381 milinches which equal 1.381 in. . 6 If the elementary heating system of Question 3 is installed with a 1-in. pipe line, how will it function? It is found from the answer to Question 3 that the pressure head is 954 milinches and from the answer to Question 5 that the friction head is 1381 milinches when the water is flowing with such velocity that the specified 14,000 Btu will be delivered with a 20 F temperature drop through the radiators. Since the pressure head is smaller than the friction head, the system will not function as planned for the water will flow through the system more slowly and remain in the radiator longer. The temperature drop through the radiator will be more than 20 F, and the difference in the weight of the water in the return and flow risers will be greater than that intended. The final result will be that the pressure head will become equal to the friction head at a value somewhere between 954 and 1381 milinches. Since the average water temperature in the radiator will be less than 190 F, the radiator should be larger than the size given in Question 4. 7 Should a hot water heating system be designed to embody small pipes or large pipes? As pipe sizes in gravity circulation heating are reduced, the friction head is increased and it is necessary to increase the temperature drop through radiators; this lowers the average temperature of the water in the radiators and necessitates an increase in the size of the radiators, so whereas the cost of the pipe in a system is reduced, the cost of the radiators is increased. For each installation there is a definite pipe size which entails maximum economy. . As pipe sizes in forced circulation systems are reduced, friction heads are increased.so a circulating pump of greater size or capacity is required. Thus, by decreasing the size of the piping, both the first cost of the circulating pump and the cost of its operation are increased. There is a definite pipe size for every installation which is most economical. For each installation of both types of systems there is a definite pipe size entailing maxi mum economy which can be determined by a series of comparative calculations. 8 What should be the size of the radiatorsTor the elementary heating system of Question 3 in which the water enters the radiator with a temperature of 200 F and leaves with a temperature of 180 F? The average temperature of the water in the radiator is, approximately, 190 F. , If test results are available for the particular radiators to be used, and for the tempera tures named, the size of the radiators should be selected from them. If no such test results are to be had, but if test results are available for the type of radiator to be used when it is supplied with 215 F steam and placed in a 70 F room, the required size may be determined by the following ratio: The required size is to the corresponding steam radiator size as (215 -- 70)l- is to (190 -- 70)`->. This ratio works out to 1.28. Hence', the radiators should be 28 per cent larger under the conditions prescribed than 'are cor responding radiators under standard conditions. It is immaterial whether a radiator is filled with steam or with water, as long as the average temperature of its outer surface is the same in both cases. 606 Chapter 34 PIPE, FITTINGS, WEEDING i Pipe Material, Types'of Pipe Used, Dimensions of Pipe Com mercially Available, Expansion and Flexibility of Pipe, Pipe Threads and Hangers, Types of Fittings, Welding as Applied to Erection of Piping, Valves, Corrosion of Piping IMPORTANT considerations in the selection and installation of pipe and fittings for heating, ventilating, and air conditioning work are dealt with in this chapter. MATERIALS Use of corrosion-resistant materials for pipe, including special alloy steels and irons, wrought-iron, copper and brass, has increased con siderably during the past few years. The recent development of copper, brass, and bronze fittings which can be assembled by soldering or sweating permits the use of thin-wall pipe and thereby has reduced the initial cost of such installation. The following brief discussion indicates the variety of pipe materials and the types of pipe available. Wrought-Sleel 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 cylindrical 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 or butt-weld process. While the lap-weld process produces a better weld than the butt type, lap-weld pipe is 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 operation. Its advantages are its somewhat greater strength which permits use of a thinner wall arid, in the small sizes, its freedom from the occasional tendency of-welded pipe to split at the weld when bent. Wrought-iron Pipe. Wrought-iron pipe is considered to be more corro sion-resisting than ordinary steel pipe and therefore its somewhat higher 607 American Society of Heating and Ventilating Engineers Guide, 1936 first cost can be justified on the basis of 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 specimens will readily disclose the difference. Cast Ferrous Pipe. There are now available several types of cast ferrous-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 in, to 6 in., and in standard lengths of 5 or 6 ft with external and internal diameters closely approximating those of extra-strong wrought pipe. Cast ferrous pipe may be obtained coupled, beveled for welding, 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. Alloy Metal Pipe. Steel pipe bearing a small alloy of copper or other alloying element, such as molybdenum or manganese, has been claimed to possess more resistance to corrosion than plain steel- pipe and it is advertised and sold under various trade names. Copper Pipe and Fittings. Owing to its inherent resistance to cor rosion, copper and brass pipe have always been used in heating, venti lating, and water supply installations, but the cost with standard dimen sions 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 are 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 conveyed or the inaccessibility of some of the piping may warrant use of a more expensive material than plain steel. The advantages of corrosionresisting pipe and fittings should be weighed against the correspondingly higher initial cost. DIMENSIONS \ The IPS dimensions of commercial pipe universally used at the present time conform to the recommendations made by a Committee of the A.S.M.E. in 1886. Pipe up to 12 in. in diameter is made in certain definite sizes designated by nominal internal diameter which is somewhat different from the actual internal diameter, depending on the wall thick ness required. There are three weights of wrought-iron and steel pipe commonly used, known as standard-weight, extra-strong, and double-extra strong. Because of the necessity of maintaining the same external dia meter in all three weights for the same`nominal size, the added wall thickness is obtained by decreasing the internal diameter. The term full-weight, when applied to sizes below 8 in., means that the pipe is up to the nominal weight per foot. When applied to sizes between 8 and 12 in., inclusive, it often indicates that the pipe has the heaviest of several wall 608 Chapter 34--Pipe, Fittings, Welding thicknesses listed. In sizes 14 in. and upward, pipe is designated by its outside diameter (O.D.) and the wall thickness is specified. . While the demands for pipe for the heating and ventilating industry are reasonably well served by the standard-weight and extra-strong pipe, demands for pipe for higher pressures and temperatures in industry resulted in the use of a multiplicity of wall thicknesses for all sizes. Even in heating installations, the erection of piping by welding was deemed to warrant the use of pipe lighter than standard weight. For these reasons, a Sectional Committee on Standardization of Wrought Iron and Wrought Steel Pipe and Tubing functioning under the procedure of the American Standards Association was appointed to standardize the dimensions and materials of pipe. . The proposed pipe standard recommended by that sectional committee has set up several schedules of pipe including standard-weight and extra strong thicknesses which are now included in Schedules 40 and 60, re-; spectively. The schedules approved by the Sectional Committee are given in Tables 1 and 3 and the corresponding weights in Tables 2 and 4. Standard-weight pipe is generally furnished with threaded ends in random lengths of 16 to 22 ft, although when ordered with plain ends, 5 per cent may be in lengths of 12 to 16 ft.. Five per cent of the total number of lengths ordered may be jointers which are two pieces coupled together. Extra-strong pipe is generally furnished with plain ends in random lengths of 12 to 22 ft, although 5 per cent 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 three standard wall-thickness schedules of copper water tubing classified "in accordance with their principal uses as follows: . Class K--Designed for underground services and general plumbing service. Class L--Designed for general plumbing purposes. Class 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. New or exposed work generally employs copper pipe of a hard temper. All three classes are extensively used with soldered fittings. Standard dimensions, weights, and diameter and wall thickness tolerances for these classes of copper tubing are given in Table 5. 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 609 American Society of Heating and Ventilating Engineers Guide, 1936 copper tubing that has been deoxidized is used. This tubing is available in a variety of sizes and wall thicknesses. EXPANSION AND FLEXIBILITY The increase in temperature of a pipe from room temperature to an operating steam or water temperature one hundred degrees or more above room temperature 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 temperature is termed the coefficient of linear expansion of that material, 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 6. , The elongation values in Table 6 were computed from the following formula: .. (1> Table 1. Dimensions of Welded and Seamless Steel Pipe Nominal Pips Size Nominal Wall Thicknesses pob Schedule Numbxbs ' Outbids Diam. Schedule Schedule Schedule Schedule Schedule Schedole Schedule Schedule Schedule Schedule 10 20 30 40 60 80 100 120 140 160 Ys 0.405 0.068* 0.095* M 0.540 0.088* 0.119* % 0.675 0.091* 0.126* Yt 0.840 0.109* 0.147* 0.187 % ' 1.050 0.113* 0.154* 0.218 l 1.315 0.133* 0.179* 0.250 1.660 0.140* 0.191* 0.250 1.900 0.145* 0.200* 0.281 2 2.375 0.154* 0.218* 0.343 2.875 0.203* 0.276* 0.375 3 3.500 0.216* 0.300* 0.437 3Y 4.000 0.226* 0.318* 4 4.500 0.237* 0.337* 0.437 0.531 5 5.563 0.258* 0.375* 0.500 0.625 6 6.625 0.280* 0.432* 0.562 0.718 8 8.625 0.250 0.277* 0.322* 0."406 0.500* 0.593 0.718 0.812 0.906 10 10.75 0.250 0.307* 0.365* 0.500* 0.593 0.718 0.843 1.000 1.125 12 12.75 0.250 0.330* 0.406 0.562 0.687 0.843 1.000 1.125 1.312 14 O. D. 14.0 0.250 0:312 0.375 0.437 0.593 0.750 0.937 1.062 1.250 1.406 16 O. D. 16.0 0.250 0.312 0.375 0.500 0.656 0.843 1.031 1.218 1.437 1.562 18 O. D. 18.0 0.250 0.312 0.437 0.562 0.718 0.937 1.156 1.343 1.562 1.750 20 O. D. 20.0 0.250 0.375 0.500 0.593 0.812 1.031 1.250 1.500 1.750 1.937 24 O. D. 24.0 0.250 0.375 0.562 0.687 0.937 1.218 1.500 1.750 2.062 2.312 30 O. D. 30.0 0.312 0.500 0.625 ........ -- ------- --...... -- ........ All dimensions are given in inches. The decimal thicknesses listed for the respective pipe sizes represent their nominal or average wall dimensions and include an allowance for mill tolerance of 12.5 per cent under nominal thicknesses. *Thicknesses marked with asterisk in Schedules 30 and 40 are identical with thicknesses for standard- weight pipe in former lists; those in Schedules 60 and 80 are identical with thicknesses for extra-strong pipe in former lists. The Schedule Numbers indicate approximate values of the expression 1000 x P/S. Chapter 34--Pipe, Fittings, Welding where it = length at temperature t degrees Fahrenheit, feet. Lo = length at 32 F, feet. t = final temperature, degrees Fahrenheit. a and b are constants as follows: - Metal a 0.005441 0.006212 0.006503 0.009278 b 0.001747 0.001623 0.001622 0.001244 The three methods by which the elongation due to thermal expansion may be taken care of are: 1. Expansion joints. 2. Swivel joints. .' 3. Inherent flexibility of the pipe itself utilized through pipe bends, right-angle turns, or offsets in the line. Table 2. Nominal Weights of Welded and Seamless Steel Pipe Nominal Pipe Size Inches SCBXD. 10 Plain Ends SCHED. 20 Plain Ends Schedule 30 Plain Ends Threads and Coup lings Schedule 40 Plain Threads and ' Coup lings SCHED. 60 Plain Ends SCHED. SO Plain Ends SCHED. 100 Plain Ends SCHED. 120 Plain Ends SCHED. 140 Plain Ends SCHED. 160 Plain Ends U, 0.25* 0.25* 0.32* 0.43* 0.43* 0.54* % 0.57* 0.57* 0.74* Yt 0.86* 0.86* 1.09* 1.31 Y 1 1.14* 1.14* 1.68* 1.69* 1.48* 2.18* 1.94 - ' 2.85 1M 2.28* 2.29* 3.00* 3.77 1Y 2.72* 2.74* 3.64* 4.86 2 3.66* 3.68* 5.03* 7.45 ,2Y 5.80* 5.82* 7.67* 10.0 3 7.58* 7.62* 10.3* 14.3 3Y 9.11* 9.21* 12.5* 4 10.8* 10.9* 15.0* 19.0 22.6 5 14.7* 14.9* 20.8* 27.1 33.0 6 19.0* 19.2* 28.6* 36.4 45.3 8 10 ____ 22.4 28.1 24.7* 25.6* 28:6* 28.8* 34.3* 35.0* 40.5* 41.2* 35.7 43.4* 54.8* 64.4 50.9 77.0 60.7 67.8 74.7 89.2 105.0 116.0 12 33.4 43.8* 45.0* 53.6 55.0 73.2 88.6 108.0 126.0 140.0 161.0 14 O. D. 36.8 45.7 54.6 63.3 85.0 107.0 131.0 147.0 171.0 190.0 16 O. D. 42.1 52.3 62.6 82.8 108.0 137.0 165.0 193.0 224.0 241.0 18 0. D. 47.4 59.0 82.0 105.0 133.0 171.0 208.0 239.0 275.0 304.0 20 0. D. 52.8 78/6 105.0 123.0 167.0 209.0 251.0 297.0 342.0 374.0 24 0. D. 63.5 94.7 141.0 171.0 231.0 297.0 361.0 416.0 484.0 536.0 300. D. 99.0 158.0 197.0 Weights are given in pounds per linear foot and are for pipe with plain ends except for sixes which are commercially available with threads and couplings for which both weights are listed. ' *The weights marked with asterisk in Schedules 30 and 40 are identical with weights for standard-weight pipe in orIB.L'r I^ta; those in Schedules 60 and 80 are identical with weights for extra-strong pipe in former lists. The Schedule.Numbers indicate approximate values of the expression 1000 x P/S. 611 American Society of Heating arid Ventilating Engineers Guide, 1936 Expansion joints of the slip-sleeve, diaphragm, or corrugated typesmade of copper, rubber, or other gasket material are all used for taking up expansion, but generally only for low pressures or where the inherent .flexibility of the pipe cannot readily be used as in underground steam or hot water distribution lines. Swivel joints are used extensively in low-pressure steam and hot water heating systems and in hot water supply lines. The swivel joints absorb the expansive movement of the pipe by the turning of threaded joints; In many cases the straight pipe in the offset of a swivel joint is sufficiently Table 3. Dimensions of Welded Wrought-Iron Pipe . Nominal Pipe Sbb y% Vt Y l 2" . ;m 3 . 3Y 4" 5 6 8 10 12 14 O. D. 16 O. D. 18 O. D. 20 O. D. Outside Diameter 0.40S 0.540 0.675 0.840 1.050 1.315 1.660 1.900 2.375 2.875 3.5 4.0 4.5 . 5.563 6.625 8.625 10.75 12.75 14.0 16.0 18.0 20.0 Nominal Wall Thicknesses fob Schedule Numbers Schedule 10 0.250 0.250 0.250 Schedule 20 0.312 0.312 0.312 0.375 Schedule 30 0.283* 0.313* 0.336* 0.375 0.375 0.437 0.500 Schedule Schedule 40 60 0.070* 0.090* 0.093* 0.111* 0.115* 0.136* 0.143* 0.148* 0.158* 0.208* 0.221* 0.231* 0.242* 0.263* 0.286* 0.329* 0.372* 0.414 0.437 0.500 0.562 0.562 0.510* 0.574 0.625 0.687 0.750 Schedule' 80 0.098* 0.122* 0.129* 0.151* 0.157* 0.183* 0.195* 0.204* 0.223* 0/282* 0.306* 0.325* 0.344* 0.383* 0.441* 0.510* 0.606 0.702 0.750 All dimensions are given in inches. ' The decimal thicknesses listed for the respective pipe sizes represent their nominal or-average wall dimensions and include an allowance for mill tolerance of-12.5 per cent under the nominal thickness. . Thicknesses marked with an asterisk in Schedules 30 ahd 40 are identical with thicknesses for standard- weight pipe in. former lists; those in Schedules 60 and 80 are identical with thicknesses for extra-strong pipe in former lists. ' The Schedule Numbers indicate approximate values of the expression 1000 x P/S. . flexible to take up the expansion without developing enough thrust to produce swiveling in the threaded joint. This is preferable since con tinued turning in the threaded joint may in time result in a leak, par ticularly when the pressure is high.. The amount of elongation which a swivel joint can take up is controlled by the length of the swing piece employed and by the lateral displacement which, is permissible in the long pipe runs. Probably the most economical method of providing for expansion of piping in a long run is to take advantage of the directional changes which 612 Chapter 34--Pipe , Fittings, Welding - 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 complicated1. The following approximate method, however, has been found to give reasonably good results and is deemed to be sufficiently accurate for most heating work. . Fig. 1 shows several types of expansion bends commonly used for taking up thermal expansion. The amount of pipe, L, required in each of these bends may be computed from the following formula: ' L = 6.16 ^Dt where L = length of pipe, feet. ' D = outside diameter of the pipe used, inches. A = the amount of expansion to be taken up, inches. . ' (2) - 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 Offset U bend Fig. 1. Measurement of L on Various Pipe Bends stress of 16,000 lb per square inch. When square type bends are used, the width of the bend should not exceed about two times the height. It is further assumed that the corners are made with screwed or flanged elbows or with arcs of circles having radii five to six times the pipe diameter. 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. It is especially necessary with light-weight radiators so to anchor the piping and so to give it freedom for expansion that no strain therefrom shall be allowed to distort the radiators. When expansion strains from the pipes are permitted to reach these light metal heaters they usually emit sounds of distress which are exceedingly troublesome. , ^Piping Handbook, by Walker and Crocker, and A Manual for the Design of Piping for Flexibility by the Use of Graphs, by E. A. Wert. S. Smith, and E. T. Cope, published by The Detroit Edison Company. 613 American Society of Heating and Ventilating Engineers Guide, 1936 PIPE THREADS All threaded pipe for heating and ventilating installations uses the American Standard taper pipe thread which is made with a taper of 1 in 16 measured on the diameter of the pipe so as to secure a tight joint. Threads of fittings are tapped to the same taper. The number of threads per inch vanes with the different pipe sizes. All threaded pipe should be made up with a thread paste suitable for the service under which the pipe is to, be used. Table 4. Nominal Weights of Welded Wrought-Iron Pipe Nominal PlPB ' 8izs (Inches) K kI H K H l IK 2 IK 3 3K ' 4 5 6 8 10 12 14 O. D. 16 O. D. 18 O. D. 20 O. D. SCHED. SCBED. 10 20 Schedule 30 Schedule 40 Plain Ends Plain Ends ____ ____ ___ .... 36.0 41.3 46.5 ___ 44.8 51.4 57.9 77.0 Plain Ends Threads and Couplings Plain Ends Threads and Couplings ______ ' ... 24.7* 34.3* 43.8* 53.6 61.4 80.5 103.0 .... ...... 25.0* 35.0* 45.0* ______ ______ 0.25* 0.43* 0.57* 0.86* 1.14* 1.68* 2.28* 2.72* 3.66* 5.80* 7.58* 9.11* 10.8* 14.7* 19.0* 28.6* 40.5* 53.6 62.2 81.2 103.0 115.0 0.25* 0.43* 0.57* 0.86* 1.14* 1.69* 2.29* 2.74* 3.68* 5.82* 7.62* 9.21* 10.9* 14.9* 19.2* 28.8* 41.2* 55.0 Schedule Schedule 60 80 Plain Ends Plain Fndfl 54.8* 73.2 87.6 111.0 136.0 0.32* 0.54* 0.74* 1 00* 1 4X* ?. ia* 3 00* 3 64* 5J33* 7 67* 10.3* 17 3* 15.0* 20.8* 28.6* 43.4* 54.4 88.6 104.0 Weights are given in pounds per linear foot and are for pipe with plain ends except for sizes which are commercially available with threads and couplings for which both weights are listed. ' *Weights marked with an.asterisk in Schedules 30 and 40 are identical with weights for standOrd-weigkt pipe in former lists; those in Schedules GO and 80 are identical with weights for extra-strong pipe in former lists. . The Schedule Numbers indicate approximate values of the expression 1000 x P/S. HANGERS 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 614 34Chapter --Pipe, Fittings, Welding ooorts 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 oermit swinging without setting up severe bending action in the rods. For pipes of small size, perforated metal strip is often used. For horizontal 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 con siderable thermal expansion, either the hangers should be designed to prevent excessive load on the bottom support when expansion takes place, or the bottom support should be designed to withstand the entire load. 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 in., Table 5. Standard Dimensions, Weights, and Diameter and Wall Thickness Tolerances for Copper Water Tubes* (All Tolerances Plus and Minus) Permissible Actual Nominal Size, In. Outbids Diam eter, Variation in Mean Outside Diameter, In. In. Annealed Hard Drawn WALL THICKNESS. IN. Class K Class L Class M Per Per Per Nominal missible Varia Nominal missible Varia Nominal missible Varia tion tion tion Weight per Ft Lb Class Class Class . K LM Vs 0.500 0.0025 0.001 0.049 0.004 0.035 0.0035 0.025 0.0025 0.269 0.198 0.144 K 0.625 0.0025 0.001 0.049 0.004 0.040 0.0035 0.028 0.0025 0.344 0.285 0.203 Vi 0.875 0.003 0.001 0.065 0.0045 0.045 0.004 0.032 0.003 0.641 0.455 0.328 l 1.125 0.0035 0.0015 0.065 0.0045 0.050 0.004 0.035 0.0035 0.839 0.655 0.464 1K 1.375 0.004 0.0015 0.065 0.0045 0.055 0.0045 0.042 0.0035 1.04 0.884 0.681 m 1.625 0.0045 0.002 0.072 0.005 0.060 0.0045 0.049 0.004 1.36 1.14 0.94 2 2.125 0.005 0.002 0.083 0.005 0.070 0.005 0.058 0.0045 2.06 1.75 1.46 IK 2.625 0.005 0.002 0.095 0.005 0.080 0.005 0.065 0.0045 2.92 2.48 2.03 3 3.125 0.005 0.002 0.109 0.005 0.090 0.005 0.072 0.0045 4;00 3.33 2.68 3K 3.625 0.005 0.002 0.120 0.005 0.100 0.005 0.083 0.005 5.12 4.29 3.58 4 4.125 0.005 0.002 0.134 0.006 0.110 0.005 0.095 0.005 6.51 5.38 4.66 5 5.125 0.005 0.002 0.160 0.006 0.125 0.006 0.109 0.005 9.67 7.61 6.65 6 6.125 0.005 0.002 0.192 0.006 0.140 0.006 0.122 0.005 13.87 10.20 8.91 From Standard Specifications for Copper Water Tube of the American Society for Testing Materials, A.S.T.M. Designation B88-331 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 character of the service and the pressure. As in the case of pipe, there are several weights of fittings manufactured. Recognized American Standards for the various weights are as follow: 615 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Cast-iron pipe flanges and flanged fittings for 25 lb (sizes 4 in. and larger), 125 lb, and 250 lb maximum saturated steam pressure. Malleable iron screwed fittings for 150 lb maximum saturated steam pressure. Cast-iron screwed fittings for 125 and 250 lb maximum saturated steam pressure. Steel flanged fittings for 150 and 300 lb maximum steam service pressure. 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. Table 6. Thermal Expansion of Pipe in Inches per 100 Ft3 (For superheated steam and other fluids refer to temperature column) Saturated Steam Elongation in Inches per 100 FT PROM --20 F UP Saturated Steam Elongation in Inches per 100 FT PROM --20 F UP Vacuum Inches of Hg. Pressure Pounds per k Square Inch Gage' Tem perature Degrees Fahren- heit CastIron Pipe Steel Pipe Wrought Iron ' Pipe Copper Pipe Pressure Pounds . per . Square .Inch Gage Tem perature Degrees Fahren heit CastIron Pipe 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 2.5 220 10.3 240 20.7 260 34.5 280 52.3 300 74.9 320 103.3 340 138.3 360 180.9 380 232.4 400 293.7 420 366.1 440 451.3 460 550.3 480 0 0 0 0 664.3 500 3.847 4.296 4.477 6.110 0.127 0.145 0.152 0.204 795.3 520 4.020 4.487 4.677 6.352 0.255 0.293 0.306 0.442 945.3 540 4.190 4.670 4.866 6.614 0.390 0.430 0.465 0.655 1115.3 560 4.365 4.860 5.057 6.850 0.518 0.593 0.620 0.888 1308.3 580 4.541 5.051 5.268 7.123 0.649 0.725 0.780 1.100 1525.3 600 4.725 5.247 5.455 7.388 0.787 0.898 0.939 1.338 1768.3 620 4.896 5.437 5.660 7.636 0.926 1:055 1.110 1.570 2041.3 640 5.082 5.627 5.850 7.893 1.051 1.209 1.265 1.794 2346.3 660 5.260 5.831 6.067 8.153 1.200 1.368 1.427 2.008 2705 680 5.442 6.020 6.260 8.400 1.345 1.528 1.597 2.255 3080 700 5.629 6.229 6.481 ,8.676 1.495 1.691 1.778 2.500 . 720 5.808 6.425 6.673 8.912 1.634 1.852 1.936 2.720 740 6.006 6.635 6.899 9.203 1.780 2.020 2.110 2.960 760 6.200 6.833 7.100 9.460 1.931 2.183 2.279 3.189 780 6.389 7.046 7.314 9.736 2:085 2.350 2.465 3.422 800 6.587 7.250 7.508 9.992 2.233 2.519 2.630 3.665 820 6.779 7.464 7.757 10.272 2.395 2.690 2.800 3.900 840 6.970 7.662 7.952 10.512 2.543 2.862 2.988 4.145 860 7.176 7.888 8.195 10.814 2.700 3.029 3.175 4.380 880 7.375 8.098 8.400 11.175 2.859 3.211 3.350 4.628 900 7.579 8.313 8.639 11.360 3.008 3.375 3.521 4.870 920 7.795 8.545 8.867 11.625 3.182 3.566 3.720 5.118 940 7.989 8.755 9.089 11.911 3.345 3:740 3.900 5.358 960 8,200 8.9?5 9.300 12.180 3.511 3.929 4.096 5.612 980 .8.406 9.196 9.547 12.473 3:683 4.100 .4.280 5.855 .1000 8.617 9.421 9.776 12.747 aFrom Piping Handbook, by Walker and Crocker. This table gives the expansion from -- 20 F to the temperature in question. To obtain the amount of expansion between any two temperatures take the difference between the figures in the table for those temperatures. For example, if a steel pipe is installed at a temperature of 60 F and is to operate at 300 F, the expansion would be 2.519 -- 0.593 = 1.926 in. Screwed fittings include: nipples or short pieces of pipe of varying lengths; couplings, usually of wrought iron only;.elbows for turning angles of either 45 deg or 90 deg; return bends, which may be of either the close or open pattern, and may be cast with either a back or side outlet; tees; 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- 616 Chapter 34--Pipe, Fittings, Welding age f 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 is shown in. Fig. 2. Table 7. Tentative American Standard Dimensions of Elbows, 45 Deg Elbows, Tees, and Crosses (Straight Sizes) for 125 Lb Cast-Iron Screwed Fittings ' .-A-- ELBOW 45* ELBOW A Nominal Pipe Size Center to End, Elbows, Tees and Crosses cB E Center to End, 45 Dbg Elbows .Length op Thread Min. Width op Band, Mm. ?. Inside Diameter op Fitting Min. Max. G Metal Thickness,- Min. H Outside Diameter op Band. Mm. Vi Vs )4 H 1 lX 114 2 2H 3 3)4 4 6 6 8 10 12 14 O.D. 16 O.D. 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 8.08 9.50 10.40 11.82 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 All dimensions given in inches. 0.32 0.36 0.43 0.50 0.58 0.67 0.70 0.75 0.92 0.98 1.03 1.08 1.18 1.28 1.47 1.68 1.88 2.00 2.20 0.38 0.44 0.50 0.56 0.62 0.69 0.75 0.84 .0.94 1.00 1.06 1.12 1.18 1.28 1.47 1,68 1.88 2.00 2.20 0.540 0.584 0.675 0.719 0.840. 0.897 1.050 1.107 1.315 1.385 1.660 1.730 1.900 1.970 2.375 2.445 2.875 2.975 3.500 3.600 4.000 4.100 . 4.500 4.600 5.563 5.663 6.625 6.725 8.625 8.725 10.750 10.850 12.750 12.850 14.000 14.100 16.000 16.100 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 0.880 1.000 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 16.94 19.30 Fittings for copper pipe of IPS dimensions are available in screwed or soldered types of connection. The compression type, fitting is generally limited to smaller size tubing while the flared and soldered types are used in large and small sizes. While no effort has been made to standardize dimensions of flared tube fittings, manufacturers have quite generally used S.A.E. standard dimensions. Flared tube fittings are widely used in refrigeration work and the use of S.A.E. dimensions and a 45 degree flare renders most fittings 617 . of andAmerican Society Heating Ventilating Engineers Guide, 1936 interchangeable, although for refrigeration use, thread fits and tolerances on thread gages must be maintained within close limits. Ammonia pipe fittings made of cast iron are extensively used in handling refrigerants in larger installations. Until recently, no standard dimensions were adhered to in the manufacture of ammonia flanged fittings or com panion flanges with the result that fittings of different manufacturers were not interchangeable. A subcommittee of A.S.ASectional Com mittee B16 has prepared proposed American Standard dimensions tor ammonia flanged fittings and companion flanges for maximum service pressure of 300 lb per sq in. which will be available soon. Thread Connections Threads used for fittings are the same American Standard taper pipe threads as those used for pipe, and unless otherwise ordered, right-hand SOLDER-TYPt FITTING REFRIGERATOR TYPE FIARED-TU81NG FITTINGS SAE COMPRESSION TUBING FITTINGS FLARED-TUBING FITTINGS Fig. 2. Copper or Brass Tubing Fittings threads are used. 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 known to the trade as pitched elbows and are commercially available. 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. . Flanged fittings are generally used in the best practice for connecting all piping above 4 in. in diameter. While screwed fittings may be used for the larger sizes and are satisfactory under the proper working con ditions, it will be found difficult either to make or to break the joints in these large sizes. . A number of different flange facings in common use are plain face, 618 Chapter 34--Pipe, Fittings, Welding raised face, tongue and groove, and male and female. Cast-iron fittings for 125 lb pressure and below are normally furnished with a plain face, while the 250 lb cast-iron fittings are supplied with a H6-`nch raised face. The standard facing for steel flanged fittings for 150 and 300 lb is a Table 8. American Standard Dimensions of Tees and Crosses (Straight Sizes) for 125 Lb Cast-Iron Flanged Fittings TEE SIDE OUTLET CROSS NOMINAL Pm 8nE*-b A Center to Face CTreoessseasnbd-e AA Face to Face Tees and Crosses b-c Diameter or Flange Thickness or Flange, Mm. Metal Thickness or Boot, Mm. i IX m 2 2X 3 3X 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. 3X 3X 4 m 5 5X 6 6X 7X 8 9 11 12 14 15 16M 18 22 25 28 31 34 7 7X 8 9 10 11 12 13 15 16 18 22 24 28 30 33 36 44 50 56 62 68 iX 4% 5 6 7 7X 8X 9 10 11 13M 16 19 21 23M 25 27X 32 38M 46 53 59X Mb X X6 X `Ms X `Ms `Mb `Mb 1 1X 1Mb IX . IX 1Mb 1Mb l`Ms IX 2X 2X 2X 2X Mb , Mb Mb Mb Mb Mb Mb X X Mb X X `Mb X 1 1Mb IX IX 1Mb IX 1`Mb 2 All dimensions given in inches. Si& of all fittings listed indicates nominal inside diameter of port. bTees. side outlet tees, and crosses, 16 in. and smaller, reducing on the outlet, have the same dimensions center to face, and face to face as straight size fittings corresponding to the size of the larger opening. 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 size fitting of the larger opening. H6-inch 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 619 of andAmerican Society Heating Ventilating Engineers Guide, 1936 fittings are given in Table 7, whereas the dimensions for 125 lb cast-iron flanged fittings are given in Tables 8 and 9. For low temperature service not to exceed about 220 F, a number of paper or vegetable fiber gasket materials will prove satisfactory; for plain Table 9. American Standard Dimensions of Elbows for 125 Lb Cast-Iron Flanged Fittings Nominal Pipe Sox a A Bc Center to Face Elbow b-o-d Center to Face Long Radius Elbow b-o-d Center to Face 45 Deo Elbow c Diameter op Flange Thickness op Flange, Min. Metal Thickness op Boot, Min. i ih lH ` 2 2M 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. 3H 4 4H 5 5\4 6 Q\4 714 8 9 11 12 14 15 16H 18 22 25 28 31 34 5 5M 6 f>/4 7 7H m 9 10H 11 H 14 16H 19 21M 24 26J4 29 34 41H 49 56H 64 m 2 m 2H 3 3 3H 4 m 5 5H , 6H 7)4 7\4 8 . 8/4 9H 11 15 18 21 24 N 4H m 5 6 7 7)4 8H 9 10 11 13 H 16 19 21 2ZH 25 27K 32 38h 46 53 5914 He Yt He H `He H `He `He `He 1 1/4 lHe 1H . m lHe lHe l`He 1H 2H 2% 2% 2H . He Ke K6 He . Ke ^6 K6 H He H H `He % l lHe 1X 1H lHe lHs l`He 2 AH dimensions given in inches. . Size of all fittings listed indicates nominal inside diameter of port. bReducing elbows and side outlet elbows carry same dimensions center to face as straight size elbows . corresponding to the size of the larger opening. - - -\ ' -' eSpedal degree elbows, ranging from 1 to 45 deg, inclusive, have the same center to face dimensions as given for 45 deg elbows and those over 45 deg and up to 90 deg, inclusive, shall have the same center to face dimensions as given for 90 deg elbows. The angle designation of an elbow is its deflection from straight line flow and is the angle between the flange faces. dSide outlet elbows shall have all openings on intersection center-lines. raised face flanges, rubber or rubber inserted gaskets are commonly employed. 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 tern- 620 Chapter 34--Pipe, Fittings, Welding perature conditions, but preferably only with a relatively 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 a competitive 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. 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 com monly used to produce acceptable welds. 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. Industry will not accept the employment of mechanics of undetermined ability nor on the basis of past experience. Neither does industry accept the statement that a weld is only as good as the workman who makes it. The control Codes now in process of adoption will be the law governing the use of the welding process. These Codes prohibit individual practices contrary to their specified procedure and rules of control, and this is predicated upon the sound requirement that the employer must assume full responsibility for the deposited weld. It is advisable that this management responsibility be included in all welding specifications and that, authoritative standards of workmanship also be specified. The standards of workmanship for this industry are as set forth in the Standard Manual on Pipe Welding of the Heating, Piping and Air Conditioning Contractors. National Association. ., A complete line of manufactured steel welding fittings is now available with plain ends machine beveled for welding and with radii similar to short and long radius flanged fittings. Some typical types of these fittings are shown in Fig. 3. They are made in pipe sizes % to 24 in., standard and extra heavy, in steel, wrought iron, brass, copper, and special alloys.- Socket welding, fittings of forged steel are also commercially available. These fittings have a machined recess into which the pipe slips. A fillet weld between the pipe and socket edge provides a pressure-tight-joint. A 621 American Society of Heating and Ventilating Engineers Guide, 1936 proposed American Standard containing dimensions of steel welding-neck flanges for pressures up to 1500 lb per sq in. has been developed in A.S.A Sectional Committee B16. Tables 10 and 11 give these dimensions for welding-neck flanges suitable for 150 and 300 lb per sq in. gage pressure. 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 sizes either cast-iron, cast-steel or some of the steel alloys are employed. Chapter 34--Pipe, Fittings, Welding sizes 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 a high resistance to flow and Table 10. Proposed Dimensions of Steel Welding Neck Flanges for Maximum Steam Service Pressure of 150 Lb per Sq In. (Gage) at a Temperature of 500 F, and 100 Lb at 750 F a. Typical Short Radius Elbows =5!-- =ass^= ; ZZZZZ^ b. Tee c. Forged Cap d. Concentric Reducer e. End , Closure Fig. 3. Typical Welding Fittings . ' ' '\ 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 pres sure. 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. These valves may be secured with either a rising or a non-rising stem, although in the smaller 622 Nominal Pipe Sob Diameter 07 Flange Thickness Diameter or or Flo. Min. Hub Hub Diam. Beginning or Cbauteb Length Thbu Hub 0 0 X. H Y DUU. FOB Standard Pipe A Diam. or ' Bolt Circle No. or Bolts Size or BOLT8 i i% 2 2% 3 3% 4 5 6 8 10 12 14 0. D. 16 0. D. 18 0. D. 20 O. D. 24 O. D. w We 5 6 7 m m 9 10 11 13% 16 19 21 25% 25 32 He % He H We % We We We 1 m We 1% 1% We We IWe. We IWe We We We We 4% 4We We We We 9We 12 U% 15% 18 19Ye 22 26K 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 We 2% We 2% 2% 2% 2We 3 3% 3% 4 4 4% 5 5 5% 5^8 6 1.05 1.38 1.61 2.07 2.47 3.07 3.55 4.03 5.05 6.07 7.98 10.02 12.00 13.25 15.25 17.25 19.25 23.25 3% 3% 3% 1% 5% 6 7 7% m 9% 11% 14% 17 18% 21% 22% 25 29% 4% 4% 4% 4H 4% 4 Ye 8% 8 Ye 8% 8% 8% 12 Ve 12 Ve 12 1 16 1 16 1% 20 1% 20 1% All dimensions given in inches. --------------------- "* *" *o iuuuucu *4* uj mnnrnum. It is recommended that the taper of the hub should not exceed 6 degrees for a reasonable distance back oi the chamfer in order to reduce the heat transfer while welding. may'prevent complete drainage of the pipe line. These objections are of particular importance in heating work. 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 623 American Society of Heating and Ventilating Engineers Guide, 1936 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 in any position. Standard roughing-in dimensions for angle-type valves are given in Table 12. Automatic control of steam supply to individual radiators can' be Table 11. Proposed Dimensions of Steel Welding Neck Flanges for Maximum Steam Service Pressure of 300 Lb per Sq In. (Gage) at a Temperature of 750 F Chapter 34--Pipe, Fittings, Welding for use in hot water heating systems are of less complex 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 requiredat 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 Table 12. Standard Roughing-in Dimensions Angle Type Valves Nominal .. Pipe Size Diam. OF Flanob Thick-. NESS OF Flange Min. Diam. of Hub Hub Diam. Beginning OF Cbamper 0QX H- *2. 2% 3 3% 4 5 6 8 10 12 14 O. D. 16 O. D. 18 O. D. 20 O. D. 24 O. D. 6% m m 9 10 11 12% 15 17% 20% 23 25% 28 30% 36 % 1 1% 1%6 1% .1% 1%6 1% 2 2% 2% 2% 2% 2% 3%fi 3^6 4% 5% 5% 7 8% io% 12 % 14% 16% 19 21 23% 27% 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 Length Thru Hub Y 2% 3 3% 3%fi 3% 3% 3% 4% m 5% 5%' 5% 6% 6% 6% Diam. FOB Standard Pipe Diam. FOB Extra Strong Pipe Diam. OF Bolt Circle A .A 2.07 2.47 3.07 3.55 4.03 5.05 6.07 7.98 10.02 12.00 13.25 15.25 17.25 19.25 23.25 1.94 2.32 2.90 3.36 3.83 4.81 5.76 7.63 9.75 11.75 .... 5 5% 6% 7% 9% 10% 13 13% 17% 20J-2 22% 24% 27 32 No. OF Bolts Size OF Bolts 8H 8 % 8% 8% 8% 8% 12 % 12 J1 16 1 16 i% 20 i% 20 i% 24 1% 24 m 24 i% For sizes below 2 inches use'dimensions of 600 lb flanges. All dimensions given in inches. \, A raised face of 16 in. is included in thickness offlange minimum.. . It is recommended that the taper of the' hub should not exceed 6 degrees for a reasonable distance back of the chamfer in order to reduce the heat transfer while welding. - effected by use of direct-acting radiator valves having a thermostatic element at the valve, or near to it: The direct-acting valve is usually an angle-type valve containing a thermostatic element which permits the flow of steam in accordance with room temperature requirements. These valves usually are capable of adjustment to permit; variation in room temperature to suit individual taste. . Ordinary steam valves may be used for hot water service by drilling a Vf6->n. hole through the web forming the seat to insure sufficient circulation to prevent freezing when the valve is closed. Valves made particularly 624 . R,Xh.eJtf/,?ard'Zaticm 1 the R?;hing-in Dimensions of Angle Steam and Hot Water, and Modulating tte Valves aid'FiTun^InduM^ Y coo`>erat,n f the Manufacturers Standardisation Society of a vacuum is formed by the condensation of steam after the supply pressure ' haa^dropped. Ordinary air valves permit the expulsion of air from the' radiator when steam is supplied under, pressure, but when the pressure dies down and a vacuum tends to be formed the air is drawn back into the radiator. : . A system supplied with vacuum valves will heat more quickly and stay warm longer than one provided with straight pressure air valves; , thus it will effect considerable economy of fuel because the idle period during which no heat is delivered is shortened. Automatic air valves are provided with a float to close them in case the radiator becomes flooded with water because it does not drain properly. . . . ," ; - 625 of andAmerican Society Heating Ventilating Engineers Guide, 1936 CORROSION2 Corrosion is sometimes encountered in heating work on the outside of buried pipes or the inside of steam heating systems; it is seldom ex perienced in hot water heating systems unless the water is frequently renewed. Piping buried in the ground is quite successfully protected by coatings of the asphaltic type which are usually applied hot and often reinforced with fabric wrappings. Galvanizing by the hot-dip process and painting with specially prepared mixtures also afford some protection. Internal corrosion in steam heating systems occurs principally in the condensate return pipes and is nearly always caused by oxygen or carbon dioxide, or both, in solution in the condensate. Oxygen may enter the heating system with the steam, owing to its presence in the boiler-feed water, or it may enter as air through small leaks, particularly in systems which operate at sub-atmospheric pressures. When a steam heating system is operated intermittently, air rushes in during each shutdown period and oxygen is absorbed by the condensate which clings to the interior surfaces of the pipes arid radiators. The rate of corrosion depends upon the amounts of oxygen and carbon dioxide present in solution, upon the operating temperature, and upon the length of time that the pipe surfaces are in contact with gas-laden condensate. Another possible cause of corrosion is a flow of electric current some times resulting from faulty electrical circuits which should be corrected. Electrolytic corrosion also may occur-because of the presence of two dis similar metals, such as brass and iron, but the condensate in practically all steam heating systeins is such a weak electrolyte that this cause of corrosion is very infrequent. If trouble is experienced from corrosion, oxygen should be eliminated from the feed water by proper deaeration with commercial apparatus. The elimination of the oxygen due to air leakage is more difficult because of the-multitude of small leaks which exist around valve stems and in pipe joints. In vacuum systems, however, an attempt should be made to minimize such leakage. Carbon dioxide in varying amounts is contained in steam produced from the majority of water supplies. It is formed from the breaking down of carbonates, and bicarbonates which are present in nearly all natural waters. It can be partly removed by chemical treatment and deaeration, blit there is no simple method whereby it can be entirely eliminated. These gases cause corrosion only when in solution in the condensate; when they are mixed with dry steam their corrosive effect is negligible. The amount of gas in solution depends upon the partial pressure of that gas in the atmosphere above the surface of the solution, in accordance with the well known physical law of Henry arid Dalton*. The exact application of this law, however, assumes equilibrium conditions which do not always exist under the flow conditions prevailing in a heating system. New Light on Heating System Corrosion, by J. H. Walker (Heating and Ventilating, May, 1933). Some Fundamental Considerations of Corrosion in Steam and Condensate Lines, by R- E. Hall and A. R. Mumford (A.S.H.V.E. Transactions. Vol. 38, 1932). 626 Chapter 34--Pipe, Fittings, Welding Distinction should be made between corrosion in heating systems proper - and in the condensate discharge lines from other apparatus using steam, such as water heaters, kitchen equipment, and sterilizers. Experience has shown that in heating systems the partial pressures of the gases do not reach such magnitudes as to cause harmful amounts of gas to become dissolved in the condensate when steam supplies are of reasonable purity. In other kinds of steam-using apparatus which are not ordinarily well vented, the gases tend to accumulate in the steam space and to become dissolved in the condensate in appreciable concentrations. Consequently, ' corrosion is frequently observed in the condensate discharge lines from such apparatus; but this does not necessarily indicate that equally serious corrosion is taking place in the heating system supplied with steam from the same source. When corrosive conditions are believed to exist, their seriousness should be determined by actual measurement, rather than by inference from isolated instances of pipe failures. The National District Heating Associa tion has perfected a corrosion tester for measuring the inherent corrosive ness of existing conditions. This corrosion tester consists of a frame sup porting three coils of wire which are carefully weighed. After the tester has been inserted in the pipe line for a definite length of time, the loss of weight of the coils, referred to an established scale, indicates the relative corrosiveness of the condensate. Accompanying such corrosion measure ments, a careful chemical analysis should be made of the condensate, and the findings will serve as a basis for an intelligent study of the problem. Corrosion, if found to exist, can. be lessened or overcome by several means. If the steam supply is found to be definitely contaminated, proper chemical treatment of the water, followed by deaeration, is an obvious remedy. The leaks in the piping system, particularly in vacuum systems, should be stopped so far as is practicable. -Sbme success has been reported with the use of inhibitors, chief among which are oil, sodium silicate, and ammonia. Oil may be fed into the main steam-supply pipe by means of a sight-feed lubricator. The type of oil known as 600-W is usually recommended. In the present state of knowledge on this point, the quantity to be fed can best be determined by trial. The use of sodium silicate, fed in a similar manner, is reported to be successful but it has not been widely used. The effect of ammonia is to increase the pH value of the condensate above the point where corrosion is likely to take place. Speller4 reports having injected small quantities of ammonia into a small closed heating system (the entire amount of condensate being returned to the boiler) and finding the pH value maintained at a high point for several months without further additions of ammonia. . The concentration of ammonia must be kept low to avoid corrosion of brass parts of the system. The use of ammonia is not to be recommended where steam riiay come in contact with food or other materials. In view of the fact that corrosion is most frequently found in the return lines from special equipment, which constitute a relatively small part of the total piping in a building, a simple solution of the corrosion `Corrosion in Steam Heating Systeins, by F. N. Speller (A.S.H.V.E. Transactions, Vol. 34. 1928). 627 American Society, of Heating and Ventilating Engineers Guide, 1936 problem may be to use non-corroding materials in those certain portions of the piping system, since the higher cost will usually be an unappreciable portion of the total. Brass and copper are undoubtedly less subject to this type of corrosion than the ferrous metals, and considerable attention is now being given to corrosion-resistant linings for ferrous pipe. Castiron pipe, sometimes alloyed with other metals, also deserves con sideration. PROBLEMS W PRACTICE 1 What is the meaning of IPS brass pipe? It means that the brass pipe has the same external diameter as steel pipe in the same nominal pipe size and that the wall thickness is sufficient to allow cutting of threads for use with standard size threaded fittings. 2 Why is thin-walled copper pipe made.up with sweated joints? . If the pipe were threaded it would be necessary to use at least standard-weight wall thickness on account of the metal removed in threading. Flared ends with coupling nuts may be used, but this construction is expensive and hard to keep tight. 3 How are pipes designated in diameters of 12 in. and less? By weight and nominal size, referring to the approximate inside diameter. . 4 How are pipe sizes designated in diameters of 14 in. and more? By wall thickness and outside diameter. 5 Why are expansion joints required in steam pipes? To care for the change in length of the line brought about by a change in temperature. 6 What devices are used for taking up expansion? Expansion joints; swivel joints, and the inherent flexibility of the pipe itself. 7 Where are swivel joints principally used? In branch connections to radiators, and in the risers of multi-story buildings where they are installed between the floor joists. 8 Name three grades of American Standard screwed pipe fittings. 125-lb cast-iron, 150-lb malleable iron, and 250-lb cast-iron. 9 0 In what sizes are American Standard cast-iron flanges and flanged fittings for 25rlb saturated steam pressure made? . In nominal sizes from 4 in. to 72 in., inclusive. - 628 Chapter 35 WATER SUPPLY PIPING AND WATER HEATING Maximum Possible Flow* Maximum Probable Flow, Average Probable Flow, Factor of Usage, Kind, of Pipe Used, Sizing of Risers, Sisdng of Mains, Sizing of Systems, Hot Water Supply, Hot Water Heating, Hot Water Storage, Swimming Pool Heating Requirements DOMESTIC water supply systems present the engineer with a design problem that requires combining the somewhat empirical rules and formulae in use with the more or less exact hydraulic principles involved. Unlike heating and ventilating layouts, there are practically no definite data for estimating the quantity of water likely to be consumed or the probable rate of water flow at any particular moment. . Metered results in one building often show two or three times the metered amount in another building of the same size and with the same type of tenants. In hotels, one riser will often have an almost constant flow that may never be reached by another at peak load. In office buildings, the women's toilets show a far greater daily consumption than tho^of the men, yet at no time will they approach the hourly consump tion of the men's toilet during the first hour of the day. This condition has led to a multiplicity of rules of practice which vary as much as the data used. All must of necessity be based on an assumed rate of con sumption and on an assumed probability of simultaneous use, and while the formulae employed may have been derived on sound technical bases the assumptions are often in error. To arrive at a safe standard, the approximate rate of flow of each fixture to be supplied must be known and the probable number of fixtures in use at any one time must be assumed. Obviously, the maximum number of fixtures assumed to be in use must be taken at the peak of _ demand and the lines must be made adequate to supply such a peak regardless of the riser or branch on which the demand may occur. This means that all water piping under the usual conditions will be over-sized. In tall buildings it is customary to divide the water supply systems, both hot and cold, into sections of 10 to 20' stories. Such zoning1 or *It is impractical to attempt to size piping so as to produce the proper pressure on fixtures at different levels by employing friction, owing to the fact that this friction will be built up to the amount desired only in times of maximum demand and at all other times the friction will be only a fraction of the maximum friction so that the fixtures by this method are subjected to a varying pressure on the water supply line. A much more practical method is to throttle the flow at the fixture, or'to'use flow regulators, so that the quantity of water delivered will approximate the fixture demands and so that this is accomplished without splashing or noise. ' . 629 American Society of Heating and Ventilating Engineers Guide, 1936 seclionalizing is for the purpose of avoiding excessive pressures on the fixtures in the lower stories of each system. This limits the consideration of water pipe sizes to horizontal mains and to risers not exceeding 20 stories in height or about 200 ft. . For the purpose of this chapter the following terms will be used and should be clearly distinguished from one another: Maximum Possible Flow: The flow which would occur if the outlets on all fixtures were opened simultaneously. This condition is seldom, if ever, obtained in actual practice except in cases of gang showers controlled from one common valve, and similar conditions. Maximum Probable Flow: The maximum flow which any pipe is likely to carry under the peak conditions. This is the most important amount to be considered in pipe sizing. Average Probable Flow: The flow likely to be required through the line under normal conditions. It is evident that any pipe adequate to take care of the maximum Fig. 1. Chart Showing Relation Between Maximum Possible Flow and Maximum Probable Percentage of Use ' probable flow will also be more than able to take care of the average probable flow, and hence the latter has no bearing on the pipe size. \` MAXIMUM PROBABLE FLOW There are two factors to be considered in calculating the maximum probable flow, namely, (1) the quantity of water that will.flow from the outlets when they are open, and (2) the number of outlets likely to be open at the same time. Table 1 shows the maximum approximate rate of flow from each fixture when it is in use, and will serve as a guide in estimating maximum probable flow demands although there is considerable variation in different fixtures and valves. Probably the flow under normal water pressures, or with the pressure properly throttled, will not differ greatly from the values stated. With the aid of this table it is possible to calculate the maximum possible flow with all outlets open in both the hot and cold water lines. 630 Chapter 35--Water Supply Piping and Water Heating To obtain the maximum probable flow it is necessary to multiply the maximum possible flow by a factor of usage, and this factor varies with the installation and the number of fixtures in the installation. It is evident that with two fixtures it is quite possible that both will at some time be in operation simultaneously. With 200 fixtures, it is unlikely the entire 200 would ever operate at the same time.. Consequently, the factor of usage reduces as the number of fixtures becomes greater, all other things being equal. Table 1. Approximate Flow from Fixtures Under Normal Water Pressures Fixtures Water-closets, flush valve........:...... Water-closets, flush tank................. Urinals, flush valve................ -......... Urinals, flush tank............................. Urinals, automatic tank.................. Urinals, perforated pipe per foot.. Lavatories............................ -.............. Showers, 4 in. heads, A in. inlets. Showers, 6 in. heads or larger........ Needle bath........ ................................. Shampoo spray.............. -.................... Liver spray........................................... Manicure table.................................... Baths, tub.--........................................ Kitchen sink........ ................................ Pantry sink, ordinary....................... Pantry sink, large bibb.................... Slop sinks.............................................. Wash trays........................................... Laundry tray...................... ................ Carden hose bibb.... ......................... . Cold Water (Gallons per Minute) 45a 10 30* 10 1 10 3 3 6 30. 1 2 1H 5 4 2 6 6 3 6 10 Hot Water (Gallons per Minute) 0 0 0 0 0 0 3 3 6 30 1 2 IX 5 4 2 6 6 3 6 0 Actual tests on water-closet flush valves indicate 40 gpm as the maximum rate of flow with 30 lb pres sure at the valve; this would increase to 60 spm (about 50 per cent) at 00 lb pressure. The 45 gpm has been taken as an average flow; possibly, with very low pressures just sufficient to operate the flush valve. 30 gpm could be allowed with safety- Urinal flush valves would vary proportionately in the same manner. In practice all the elements will vary according to conditions; in the case of flush valve closets the duration of flush with the kind and condition of supply apparatus, the interval between flushes with the number of people using the system and their habits; and the length of the rush period with the type of installation and its location. The effect of each of these time elements on the results should be considered in connection with any data on which it is based before -passing judgment on the selection of the factor of usage. The longer the duration of the flush the greater is the probability of overlapping flow. In selecting the factor of usage shown in Fig. 1 for systems having flush valves, 10 seconds was chosen as the maximum duration of flush, a value that represents an approximate average as water closets are installed. While the curve has been calculated for systems composed' of water closets alone, it is possible to calculate probabilities for mixed systems of water closets and other smaller fixtures. It has been found however that for two systems both having the same maximum possible flow, one com posed entirely of water closets and the other a mixed system of water American Society of Heating and Ventilating Engineers Guide, 1936 closets and smaller fixtures, the probability of a given rate of flow is greater for the system composed of water closets than for the mixed 1 s A <N B Z s pi . Ma. S z U6QW3. o < O z St o o Q a j UeOrtf ca A g tCNnd c/5- s 3 2 s t~ g g eo lO CM 8 iA O lO r r oLpb 250 X eo CO x CM xX CM CM XX CM CM X CM X CM XX CM CM XX CM CM X CM XX CM CM XX CM CM X CM CM x CO X CM CM XX CM CM XX CM CM CM X CM X CM CM XX CM CM X XX CM CM CM XX CM CM XX CM CM CO CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CO CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CO CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM CM X CM CM x 33 3X X X 33 3X 3 XX XX 33 X CM CM X rH 33 33 3 X X3 3X 3 X3 3X 33 X CM 5 X 3X 3 X. 3 3 X3 33 3 XX XX XX CM x 5 3 3 3 3 3 3 3 3 3 3 3 3 X 3 3 3 X CM' 5 3 3 3 3 3 3 X 3 3 3 X 3 3 3 3 3 X 3 CM * 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 X X wH - - 5_ _ .- - - X '_ - -- 3 * Xx xx X X XX XX XX XX XX ^- & Xx X XX X XX X XX Xx XX x & x X X is X X X X X X X XX XX XX s m s s 8o eo CM CO CO o eo eo eo eo CO eo CO . o eo eo eo CO 100 F t able A llow D pe P or tio n of R is e r o> ft. O * *-1 Ed ft, ft] O tq earf ze \ Ss cc c c ---- cc -- 5 | t f I i S 1 ; a" cm - - - - g * tt.U Ml 1SMM 11 MiT Ho tfi -` -M O Og (i. fa system. The use of this chart then would produce results which would be on the safe side for mixed systems. For systems composed entirely of .fixtures other than flush valve fixtures the curve has been extended for smaller maximum possible flow values. 632 Chapter 35--Water Supply Piping and Water Heating . This chart applies to a normal building and not to installations where the inmates may all be required, for instance to bathe on certain days of the week and at certain hours of those days; or in schools for example where all the showers in the gymnasium may be used simultaneously after instruction periods. In such special cases a new factor of usage must be developed based on the maximum probable usage under the conditions involved. Example 1. Assume that in a normal building, such as a residential hotel or an apart ment house, there are 50 flush valve water-closets, 50 lavatories, 50 sinks and 50 baths, and that it is desired to determine the maximum probable flow in a line supplying all of these fixtures with both hot and cold water. Cold Water 50 W. C. x 45 gpm.............. 2250 gpm 50 Lavs, x 3 gpm......................... 150gpm 50 Sinks x 4 gpm......................... 200gpm 50 Baths x 5 gpm......................... 250gpm Maximum possible flow......2850 gpm Fig. 1 shows a factor of usage of 9 per cent. Maximum probable flow of cold water is 2850 X 0.09--................ 257 gpm Hot Water 50 Lavs, x 3 gpm................. 150 gpm 50 Sinks x 4 gpm................. 200 gpm 50 Baths x 5 gpm............ .. 250 gpm Maximum possible flow...... 600 gpm Fig. I shows a factor of usage of 23 per cent. Maximum probable flow of hot water is 600 x 0.23..--...................... 138 gpm Total for main supplying cold and hot water (2850 + 600) X 0.08........ .................................... 276 gpm It should be noted that this is a rate of flaw or an instantaneous demand. KIND OF PIPE USED Before entering into the actual sizing of pipe, it is necessary to consider the kind of pipe to be used, and to make suitable allowance for corrosion and fouling during the lifetime of the system. For example, if brass, copper or alloy pipe is contemplated, it is probable that the quantities indicated in Example 1 are ample; if galvanized pipe is to be used, then it is quite likely that after a period of say 15 years the area may be decreased as much as 25 per cent and the quantitities of water assumed should be increased by 35 per cent to allow for this reduction of area; if the water contains lime it is possible that 50 per cent of the area may be lost and in such cases the flow should be doubled and no branch pipe connected to fixtures should be less than % in. In all of the following calculations, the assumption is made that the water is fairly good and that a corrosion resistant type of pipe is to be used. SIZING A DOWN-FEED RISER Down-feed systems are commonly used for tall buildings. In sizing a riser arranged for down-feed, the gravity head permits a pressure drop that is almost prohibitive in an up-feed riser. There is a gain in riser head of 0.43 X 100 or 43 lb per 100 ft of run and hence it is quite permissible to size such a riser on the basis of a pressure drop of 30 lb per 100 ft of run, as the difference between the 43 lb generated and the ,30-lb drop under maximum probable demand is ample to take care of the friction.caused by the fittings. This method applied to the typical riser shown in Fig. 2 gives the schedule of sizes indicated in Table 2 for any flow from 5 to 250 American Society of Heating and Ventilating Engineers Guide, 1936 SIZING AN UP-FEED RISER When the riser is an up-feed, the opposite condition occurs; that is, there is a drop in pressure as the top of the riser is approached, due to the natural reduction in the gravity pressure, and to this must be added the pipe friction plus that introduced by the pipe fittings, all of which produce an excessive drop when compared to the conditions existing with a down- feed riser. ' To size an up-feed riser the minimum pressure of the street main, or other source of supply, should be ascertained and from this should be subtracted the pressure to be maintained at the highest fixture, namely, 15 lb per square inch, plus the height in feet above the source of water pressure, multiplied by 0.43 to change from feet of head to pounds of pressure. The total length of run from the source of pressure to the farthest and highest fixture should be ascertained, and this should be changed to equivalent length of run to allow for the loss occasioned by Table 3. Approximate Allowances for Fittings and Valves in Feet of Straight Pipe Size or Pips (Inches) 90-Deg Elbow 45-Deg Elbow Ttpb or j*imNQ OB Valvs Return Bend Gate Valve Globe Valve Angle Valve k % i 134 2 3 4 5 6 43 53 53 64 75 75 10 7 12 8 18 13 25 18 30 21 8. 10 10 12 14 14 20 24 36 50 60 ' 2 3 3 3 4 4 5 6 9 13 15 48 60 60 72 84 84 120 144 216 300 360 8 10 10 12 14 14 20 24 36 50 60 the pipe fittings. Table 3 gives the additional lengths necessary to allow for the various fittings and valves. The drop allowable in pressure per 100 ft of run may then be obtained by multiplying the surplus pressure (over that required for the gravity head and to supply 15 lb at the fixture) by 100 and by dividing this by the equivalent length of run to the farthest or highest fixture. .% ' Where street water pressures are available the pressure drop through the meter and service pipe must be taken into consideration. Table 4 shows the pressure loss through meters. It also gives the minimum sizes of recommended service and maximum meter deliveries. Example 8. Assume a street pressure of 60 lb, the height of the highest fixture 50 ft, and the length' of the longest nm 200 ft. Without knowing the additional length of pipe to be added for the fittings it will be assumed that this is about 100 ft. The surplus pressure which will be available for pressure drop will then be 60 lb -- (15 lb + 50 ft X 0.43 lb) = 60 lb - (15 lb + 21.5 lb) = 23.5 lb. To change this into drop per 100 ft: gOO ft^-h^lOO ft = ^ Per 100 ft. The pipe may then be sized from the maximum probable flow by selecting a size that does not give a drop in excess of 7.8 lb per 100 ft. 634 Chapter 35--Water Supply Piping and Water Heating It will be seen from Example 2 that it is impossible to size up-feed . risers without determining the drop allowable in both the horizontal feed mains and the toilet room branches. Having once ascertained this allow able drop, it is simply a matter of applying it throughout the system. Table 4. Pressure Loss Through Water Disc Meters3 A. W. W. A. Standards consult manufacturers. 635 American Society of Heating and Ventilating Engineers Guide, 1936 HORIZONTAL SUPPLY MAINS The horizontal mains supplying the risers at the top of a down-feed system must be liberally sized unless the house tank is set at a much higher elevation than usual. To provide a gravity head on the highest fixtures of 15 lb per square inch it is necessary for the water line in the house tank to be nearly 40 ft higher, and with the line loss considered this becomes about 45 ft. Such heights are not often practical and as a result the pressure on the highest fixtures either is reduced to. 7 lb (which is sufficient to operate a flush valve), or flush tank water-closets are sub stituted, or a separate cold and hot water supply is installed with a small pneumatic tank to give the increase in pressure necessary. The chief objection to the use of a pneumatic tank is that a separate hot water heater is required and this heater must be located either sufficiently below the highest fixtures to obtain a gravity circulation, or it must be provided with a circulating pump in order to force the hot water to the top floor level. The most common solution is to place the hpuse tank as high as the structural and architectural conditions will permit and then to use liberally-sized lines between the house tank and the upper fixtures, say for the two top stories, below which the riser sizes may be reduced to those indicated in Fig. 2 and Table 2. Where the house tank is only one story above the top fixtures, flush tank water-closets must be used and the drop in the entire run from the house tank down to the farthest fixture should not exceed 1 lb; the less, the better. This means that if the total equivalent run to the farthest top fixtures supplied is 300 ft, the drop per 100 ft should not exceed ^ ^300 or 0-33 lb per 100 ft. The friction curves shown in Fig. 3 may be used for quickly determining the proper size of pipe to give any desired drop in pounds per 100 ft of equivalent run. OVERHEAD DISTRIBUTION MAIN Example S. Suppose an installation has a house tank in which the water line is 20 ft above the level of the top fixtures to be supplied and that the length of run to the farthest fixtures on this level is 400 ft with the pipe fittings adding another 200 ft, making an equivalent length of 600 ft. What would be the size of main coming out of the tank where a maximum flow rate of 400 gpm may be expected, of the horizontal main where a maximum flow rate of 200 gpm may be expected, and of the riser down to the fixture level where the maximum flow rate is approximately 100 gpm? Here the level of the water in the house tank is 20 ft above the faucet of the highest fixture and the gravity pressure will be 0.43 lb X, 20 ft = 8.6 lb and, if a total pressure drop of 1 lb. is assumed, the pressure on the farthest fixture under times of peak load will be 8.6 lb -- 1 lb = 7.6 lb while the drop per 100 ft of equivalent run will have to be ------ 600------ 0.16671b. , .. - Referring to Fig. 3 it will be noted that where the flow through the main is 400 gpm, an 8 in. pipe would be required; that where the flow is reduced to 200 gpm, a 6-in. pipe would be sufficient; and that where the flow is 100 gpm in the riser branch and riser, a 5-in. size would be correct. Of course these are somewhat excessive flows and the head from the tank is small so that large sizes are to be expected. It would be necessary to carry a 5-in. riser down to the branch to the top floor, then reduce to:4 in. for the branch to the floor below the top, and below this the sizes in Table 2 could be followed. In such a case, flush tank closets should doubtless be substituted. Had the tank been set 10 ft higher, the head available to be used up in' friction, but 636 Chapter 35--Water Supply Piping and Water Heating still giving the same pressure at the top fixtures, would have been 0.43 lb X 10 ft of 4.3 lb greater and this, with the 1 lb drop used previously, would give a total allowable drop of * = 3-3 vri1'c*,> divided by the 600 ft equivalent run gives a drop per 100 ft of A-3,,X.100- =0.9 lb 600 American Society of Heating and Ventilating Engineers Guide, 1936 Fig. 4. Typical Layout for Down-Feed System Water Line --------1-- House Tank'!-* House Supply Fire Reserve __ i_ 5` 197 4" 255 5* 197 4" .^ 8th. 4W.C.-F.V. 2U.-F.V. 3 Lav. ' 215 4- 6W.C.-F.V. 4 Lav. 122 3"! 1 S. S. X 166 2* 7th. 4W. C.-F.V. 2U.-F.V. 3 Lav. 211 2 5" 6W.C.-F.V. 4 Lav. ,21 2 1 S.S. 145 2' 6th. 4W.C.-F. V. 2U.-F.V. 3 Lav. 196 2*' 6W.C.-F.V. 4 Lav. 12Q 2" 1S.& ,, 117 2 '5th. 4W.C.-F.V. 2U.-F. V. 3 Lav. 180 2- 6W.C-F.V. 4 Lav. - 120 2' 1S.S. 25 1* 4th. 10 Lav. ,, 4W.C.-F.V. 160 2 2U.-F.V. ^ 3 Lav. . 3W.C.-F.V. 119 2 1 Lav. ^ 1S.S. ' 11 7 3rd. 1S.S. . 130 3 4W.C.-F.V. 2U.-F.V. 3 lav. . 90 2' 2 Lav. 8f 2nd. .1S. S. 98 1? 2W.C.-F.V. 1U.-F.V. 1 Lav. jf 3W.C.-F.V. 89 1 Lav. 4 1" .1S. S. 1st (7) 45 >7 1W. C.-F.V. -' (2) 3" 4 4 1S.S. (3) and, with this drop, the sizes according to the chart (Fig. 3) are 6 in., 5 in., and 4 in., respectively, while if the run is reduced to 200 ft instead of 600 ft, the allowable drop will be ^ ^ '^200 = ^.7 ^ Per *0 ft. This gives 5 in., 4 in., and 3 in., respectively, for the flows of 400, 200, and 100 gpm.- . . From Example 3 it is evident that, while the down-feed system possesses certain economies in size for the riser portion', it is quite likely to involve large distribution mainsizes, especially when the tank is not elevated to a considerable degree. '' SIZING A PIPING SYSTEM Example 4- Fig- 4 shows a typical layout with three risers extending eight stories and with the fixtures noted on each floor. First this wiii be solved for a down-feed arrange ment assuming that the level of the water in the house tank is 30 ft above the fixtures on the top floor, that the length of run from the tank to the farthest fixture is 200 ft, equiva lent length of fittings 100 ft, and the pressure required at the fixture is 7 lb. 638 Chapter 35--Water Supply Piping and Water Heating Table 5. Typical Calculation of Pipe Sizes on Down-Feed Riser with Flush Valve Water-Closets and Urinals (Riser No. 1. Fig. 4) FLOOR OF Bldg. 1st 2nd 3rd 4th 6th 7th ' 8th Fixtures ON Floor 1 S. S. IS. S.' 1 s. s. 10 Lav.4 W. C. 2 U. 3 Lav. 4 W. C. 2 U. 3 Lav. 4 W. C. 2 U. 3 Lav. 4 W. C. 2 U. 3 Lav. Gpm PER Fixture 4 4 4 *3 45 30 3 45 30 3 45 30 3 45 30 3 Maximum Gpm on Floor Maximum Gpm on Riser Probable Use (per cent) Probable Demand Riser Gpm Allowable Drop Lb per 100 Ft 4 4 100 4 30 4 8 100 8 30 4 12 92 11 30 30 42 58 25 30 180 60 9 .249 . 291 40 117 30 180 60 9 249 540 27 145 30 180 60 9 249 789 21 166 30 180 60 9 249 1038 19 197 2 Pipe Size In. a H % 1 2 2 2. 4 The 30-ft head is equal to a static pressure of 0.43 X 30 or 12.9 lb per square inch and to maintain a pressure of 7 lb at the highest fixtures the drop allowable in pressure is 12.9 -- 7.0 lb or 5.9 lb. As the total equivalent run is 300 ft, this is a drop per 100 ft of 1.97 lb, or practically 2 lb. Therefore, all risers and mains from the top floor back to the tank must be sized on the basis of a drop of 2 lb per 100 ft. Tables 5, 6, 7 and 8 show the schedule for Risers Nos. 1, 2 and 3 with the maximum possible flow taken from Table 1, the percentage of use at the peak taken from Fig. 1, and the maximum probable flow at the peak worked out for each portion of the riser, the riser sizes being taken from Table 2 as far as possible and from Fig. 3 where the amounts exceed the values given in this table; a drop of 30 lb per 100 ft is used except on the riser from the top floor back to the tank where 2 lb per 100 ft is the allowable limit. ' The reduction in pipe size which would occur if flush tank water-closets were used on the .top floor and only 3 lb pressure used on the fixtures is given in Tables 9 and 10. This illustrates why flush tank closets so frequently are substituted on the uppermost floor when a house tank is the source of water pressure. If it is now assumed that Riser No. 1 is to be fed from the bottom and the minimum street pressure is 75 lb with the top fixture of the riser 80 ft above the main, the problem would be solved by determining the maximum rate of flow in each portion of the riser as shown in Table 11 and then finding the allowable drop which can be used per 100 ft. The 80 ft of riser height will use up 0.43 lb X 80 = 34.4 lb and the pressure at the top of the required 15 lb will make the total reduction 49.4 lb, leaving a balance of 25.6 lb which may be used up in friction. If the distance from the street main to the bottom of the riser, which will be assumed to be the farthest one on the horizontal line, is 100 ft, and if the fittings are sufficient to add another 100 ft, as well as the 80 ft of vertical distance up the riser, the total.equivalent run will be 280 ft, which will be taken as an even 300 ft. 639 of and 1936American Society Heating Ventilating Engineers Guide, Table 6. Typical Calculation of Pipe Sizes on Down-Feed Riser with Flush Valve Water-Closets and Urinals (Riser No. 2. Fig. 4) Floor of Bldg. 1st 2nd 3rd 4th 5th 6th 7th Sth . Fixtures on Floor 1 W. C. 2 W. C. 1 U. 1 Lav. 4 W. C. 2 U. 3 Lav. 4 W. C. 2 U. 3 Lav. 6 W. C. 4 Lav. 6W.C. 4 Lav. 6 W. C. 4 Lav. 6 W. C. 4 Lav. Gpm per Fixture 45 45 30 3 45 30 3 45 30 3 45 3 45 3 45 3 45 ' .3 Maximum Gpm on Floor Maximum Gpm on Riser Probable Use (per cent) Probable Demand Riser Gpm Allowable Drop Lb per 100 Ft 45 45 100 45 30 90 30 3 123 168 58 98 30 180 60 9 249 417 ' 31 130 30 . 180 60 9 249 666 270 . 12 24 160 30 282 948 19 180 30 270 12 282 1230 16 ' 196 30 270 12 282 1512 14 .211 - 30 270 12 282 1794 12 215 2 Pipe Size In. IK IK 2 2 2 2K 2K 4 25.61b X 100 Then the allowable drop per 100 ft will be 8.5 lb and the sizes shown 300 in Fig. 5 are based on this amount of drop. Of course the other risers will have.the same maximum flows at the bottom as they formerly had at the top, namely 215 and 122 gal, respectively, for Risers Nos. 2 and 3. Combining these maximum flows in the same man ner as pursued in the down-feed system it is seen that the maximum flow between Riser No. 2 and Riser No. 3 is 255 gpm, and between Riser No. 3 and the street main, 282 gpm which at a drop of 8.5 lb gives the main sizes indicated. It will be noted that in determin ing the maximum flow in an up-feed riser it is necessary to begin at the top .floor and work down instead of beginning at the bottom floor and working up as was done in the down-feed sizing. ' SIZING UP-FEED AND DOWN-FEED HOT WATER SYSTEMS Hot water supply systems, when of the circulating type, have a few differences to be considered although the same general principles of sizing apply to these lines as to the cold water lines. Owing to the fact that there are no flush valves on the hot water piping and also because many plumbing fixtures have no hot water connections, the sizes of the hot water piping in general will be considerably less than the cold water piping in the same building. On the other hand it is almost invariably 35--Chapter Water Supply Piping and Water Heating Table 7. Typical Calculation of Pipe Sizes on Down-Feed Riser with Flush Valve Water-Closets and Urinals (Riser No. S. Fig. 4) FLOOR ' OF Bldg. 1st 2nd . 3rd 4th 5th 6th 7th 8th Fixtures ON Floor 1 s. s. 3 W. C. 1 Lav. 2 Lav. 3 W. C. 1 Lav. 1 S. S. 1 s. s. 1 s. s. 1 s. s. 1 s. s. Gpm per Fixture 4 45 3 3 45 3 4 4 4 4 4 Maximum Gpm on Floor Maximum Gpm on Riser Probable Use (per cent) Probable Demand Riser Gpm Allowable Drop Lb per 100 Ft 4 4 100 4 30 135 3 142 63 89 30 138 6 148 61 . 90 30 135 3 4 290 41 119 30 112 4 294 41 120 30 4 298 40 120 30 4 302 40 121 30 4 306 40 122 2 Pipe Size In. K IK IK 2 2 2 2 3 required that a gravity circulation be kept up in such hot water lines and this often has a considerable influence on the size. There are three methods of arranging circulation lines, as follow: 1. By using the plain up-feed with a return carried back from the top of the riser and paralleling it. 2. By carrying a supply riser up in one location thus supplying fixtures on up-feed, then crossing over at the top and coming down past another collection of fixtures and supplying these by a down-feed. 3. By carrying all of the water to the top of the building and dropping risers wherever needed, feeding all hot water on a down-feed system. Table 8. Size of Distribution Main for Down-Feed Systems (See Fig. 4) Maximum Gpm Riser Maximum Gpm Main Probable . Use (per cent) Probable Gpm Allowable Drop Lb per 100 Ft Size of Main In. 1 2 1038 1794 1038 2832 18 187 2 9 255 . 2 3 306 3138 9 282 2 4 4 5 In the first instance the up-feed riser may be sized for the same pressure drop as used for the cold water riser and, from the top of the riser just below the top fixture connection, a return circulation line may be carried back to the main return line in the basement and connected through a' check valve, set on a 45-deg angle, and a gate valve; these return circu-. lation lines should never be less than % in., and on the farther half of the risers, not. less than 1 in. to favor circulation in the far end. Typical top and bottom connections for such risers are shown in Fig. 6. 641 of and 1936American Society Heating Ventilating Engineers Guide, Table 9. Typical Calculation of Pipe Sizes on Down-Feed Risers with Flush Tank Water-Closets and Urinals on Top Floor Only (See Fig. 4) Floor of Bldg. Fixtures on Floor Gpm PER Fixture Maximum Gpm ON Floor Maximum Gpm on Riser Probable Use (per cent) Probable Demand Riser Gpm Allowable Drop Lb per 100 Ft Pipe Size In. 7th and below 8th 4 W. C. 2 U. 3 Lav. 10 10 3 7th and below 8th 6 W. C. 4 Lav. 10 3 Riser No. 1 789 40 20 9 69 868 21 20 Riser No. s 1512 60 12 82 1594 14 14 166 172 211 223 30 2 3.3 4 30 2M 3.3 4 7th and below 8th 1 s. s. 4 Riser No. 8 . 302 4 306 40 121 40' 122 30 2 3.3 3 For the second arrangement of hot water risers (Fig. 7b), circulation lines are run back from the last fixture supplied to the main return.circulation line in the same manner as just described, using % in. for the near risers and 1 in. for the far risers. The sizing is much more difficult, as it is necessary to start at the bottom floor of the return riser and work back to the top of this riser and then carry the maximum flow across on to the top of the corresponding supply riser and work down on this riser from the top floor to the bottom. Naturally this gives a much greater flow in the supply riser and aids circulation by reducing pipe friction. The allowable loss per 100 ft in such lines must be made about half that used for the cold water risers which do not have the combined up- and down-travel which the hot water must make. In the third and most common arrangement (Fig. 7c) all of the water is car ried from the tank or heater directly to the top of the building and is there distributed to the risers which are down-feed and may be sized in the Table 10. Summary of Riser Sizes to Given Main Sizes with Flush Tank Water-Closets and Urinals on Top Floor Only. (See Fig. 4) Riser No. 1 2 3 Maximum Gpm Riser 858 1594 306 Maximum Gpm Main 858 2452 2758 , Probable Use (per cent) 20 10 9 Probable Gpm 172 245 248 Allowable Drop Lb per 100 Ft 3.3 3.3 3.3 Size of Main In. 4 4 4 642 35--Chapter Water Supply Piping'and Water Heating regular down-feed manner if the total. equivalent run either from the street main or house tank is taken into consideration. The return circulation lines from the bottom of each riser should be arranged in the manner already outlined and any riser not going to the basement to supply fixtures must have these returns carried down to the basement from the termination of the supply riser at whatever level it may end. 4W.C.-FV. 2U.-F.V. 3 Lav. 8th. p*-- . 4W.C.-F.V. 24 2U.-F.V. 2 3 Lav. 7 th. 4W.C.-F.V. 24 2U.-F.V. 3 Lav. 6th. 4W.C.-F.V. T 2U.-F.V. 3 Lav. 5th. 3" 10 Lav. 4th. Top Fixture Connection and Air Vent > f*---- * |f II ' 1t ~J___ t 3" 1S.S. 3rd. 1S.S. 2nd. 3" 1S.S. 1st ? 3" Main (I) Fig. 5. Up-Feed System Fig. 6. Supply and Return Main Connections for Hot Water Supply System All risers, both hot and cold, should be valved at the main with an extra check valve on the hot water return circulation so that the risers may be cut off and repaired when necessary without disturbing the service in the remainder of the system. HOT WATER SUPPLY Having designed the service hot water piping, the next step is to furnish some means of heating the water and in this respect it is necessary to pass from the maximum probable flow to the maximum probable hourly demand, which is quite different. If an instantaneous heater were used, it would require adequate capacity to provide for the heating of the water as fast as it is drawn and a heater of this type should be sized on the basis of the maximum probable flow with the accompanying heavy drafts on the heating device and with intervals of no draft at all. To balance these inequalities of flow the storage-type heater is often utilized so that the 643 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Table 11. Typical Calculation of Pipe Sizes on Up-Feed Riser with Flush Valve Water-Closets and Urinals (See Fig. 5) Floor of Bldg. 8th 7th 6th 5th' 4th 3rd 2nd 1st Fixtures on Floor 4 W. C. 2 U. 3 Lav. 4 W. C. 2 U. 3 Lav. 4 W. C. 2 U. 3 Lav. 4 W. C. 2 U. 3 Lav. 10 Lav. 1 S. S. 1 S. S. . 1 S. S. Gpm PER Fixture Maximum Gpm on Floor Maximum Gpm on Riser Probable Use (per cent) Probable Demand Riser Gpm Allowable Drop Lb per 100 Ft 45 180 30 60 3 '9 249 249 44 109 8.5 45 180 30 60 39 249 498 28 139 8.5 45 180 30 60 39 249 747 22 164 8.5 45 180 30 60 39 249 996 . 18 179 3 30 1026 18 185 8.5 8.5 ' 4 4 1030 18 186 8.5 4 4 1034 18 187 8.5 4' 4 . 1038 18 188 8.5 Pipe Size In. 2M 2K 3 3 3 3 3 3. Table 12. Suggested Storage Tank Sizes for Homes and Apartments3 Alt, Year SERVICE . Based on Boiler Water at 180 F . SERVICE DURING HEATING SEASON Based on Boiler Water at 215 F Tank Capacity Gal Piping Connections Boiler, In. Tank, In. Number of Baths or Families 30 35 40 50 60 72 80 100 . 125 150 200 250 300 400 500 i ix ix IX ix ix 2 2 2 2 2 2X 2X 3 3 X. Vi Vi Vi 1 1 ,1 IX IX IX ix ix 2 2 . ; i i 1-2 1-2 1-2 2-3 2-3 3-4 4-5 5-6 6-7 7-9 9-11 11-15 15-18 aSee pages 645 and 705 for further data. Tank Capacity 30 . 40 N 52 66 82 100 120 144 160 200 250 300 400 500 600 Piping Connections Number of Baths or Families Boiler, In. Tank, In. i X- i i x i i Xi IX 1 1-2 ix 1 2-3 IX 1 3 IX 1 4 IX 1 5' 2 IX 6 2 ix 6-7 2 ix 7-9 2 ix 9-11. 2X 2 . 11-15 2X 2 ' 15-18 3 2X 18-21 644 Chapter 35---Water Supply Piping and Water Heating water demand can be heated during periods oi light demand and stored up for use during the periods of heavy demand. The total water con sumption per person usually varies between 100 and 150 gal per day when laundry and culinary operations for the occupants are carried out on the same premises. The maximum hourly demand under these conditions will be found to be about one-tenth of the average daily consumption. If one-third of the total water used is hot water and 125 gal per day is assumed as a fair average of consumption per person, it is apparent that each person uses about 40 gal of hot water per day. If one-tenth of this represents the peak hourly load, then 4 gph must be allowed per person for the heaviest demand. If the average occupancy of apartments is 3 persons, the peak hour demand per apartment will be about 12 gph. It is customary to allow 10 gph of heating capacity per apartment. Water in excess of this heating capacity drawn out during the peak hours is * A- 1_ * *| I \I 1 CL . * C 3 ^ T a. C3O y <aa3/>.. . aa. to S 1_ \^ 1 . / * > zs 4/ _ 1 _ .1 *L /<f (c) / t/<**- s /<& Fig. 7. Methods of Arranging Hot Water Circulation Lines provided for by storage in the hot water tank where this water is heated during hours when the demand is below the average. . Table 12 gives suggested storage tank sizes for homes and apartments based on the number of families or baths. HOT WATER HEATERS Various types pf heaters are available for supplying the hot water for domestic service in buildings. In any hot water supply system the water should be heated to a temperature between 150 and 180 F. Where the hot water requirements include supplies for kitchens, laundries or process work, the higher temperatures are used. In buildings where steam is available throughout the year, the hot water supply is usually taken from this source. In smaller domestic installations the fuel-burning device is generally automatically arranged so that hot water is supplied the entire year and not merely when the boiler is used for heating purposes. 645 American Society of Heating and Ventilating Engineers Guide, 1936 Water is heated by various methods using heat exchangers arranged so that the boiler heating medium gives up its heat to the water in the hot water circulating system. These heat exchangers may be classified as follows: ' 1. Submerged steam heating coil in storage tank. 2. Submerged water heating coil in storage tank. (Fig. 8). 3. Indirect water heater, mounted on side of boiler below water line. (Fig. 9). 4. Submerged indirect water heater, placed in boiler below water line. (Fig. 10). The efficiency of these heaters may be estimated as nearly 100 per cent as the heat loss from surface radiation of the heater and tank shell when covered with insulating material is generally reduced to a minimum. The capacities of these heaters are usually available from manufacturers Chapter 35--Water Supply Piping and Water Heating storage tank and the piping arrangement between the boiler, heater and tank. It is generally good practice to allow a margin of safety when selecting an indirect heater of the proper size to provide for loss of efficiency due to the accumulation of scaling on the coils and piping. Heat exchangers classified according to (3) and (4) may be used with or without a storage tank, but when tanks are omitted, the indirect water heaters should be increased in size so as to heat the water instantaneously as it is needed. The storage tank should be installed as high as possible. Horizontal tanks are preferable for all medium size installations and absolutely essential on larger installations. Where possible the storage tank should be installed with the bottom of the tank at or above the boiler water line. Horizontal storage tanks smaller than 18 or 20 in. diameter are not Fig. 8. Hot Water Heating Coil Submerged in Storage Tank rating tables. The area of the inside surface of a heating coil may be determined from the following equation: . where . Q X 8.33 (to - tj) 28 zr w i " A-o a fm A = surface area of coil, square feet. Q -- quantity of water heated, gallons per hour. _ to = hot water outlet temperature, degrees Fahrenheit. ti = cold water inlet temperature, degrees Fahrenheit- K0 = coefficient of heat transmission, Btu per hour per square foot surface. For copper or brass coils K0 = 240 (steam) and 100 (hot water). . For iron coils K0 = 160 (steam) and 67 (hot water). <m = logarithmic mean of the difference between the temperature of the heating medium and the average water temperature, fm is approximately = 0- Equation 1 may also be used for determining revised heating coil ratings under different temperature conditions as stated in. the manu facturers ratings. When selecting a water heater, the conditions of operation should be carefully considered, as well as the location of the 646 Fig. 9. Indirect Water Heater Mounted on Side of Boiler Fig. 10. Indirect Water Heater Placed in Boiler 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. - Pipe sizes between the water heater and boiler should be full size of the heater tappings (Table 12). When a heater is connected to a horizontal sectional boiler, it is recommended that connections be made to all sections and joined together a few inches below the water line as shown in Fig. 8, so that steaming is prevented in those sections which are not connected to the header. .. When a steam, coil is used for heating the water, an automatic ther mostatic valve may be installed in the steam supply to the coil. The operation of this automatic valve is controlled by a thermostat located in the storage tank which permits the proper amount of steam to enter the coil so as to maintain an even water temperature. An indirect water heater may be used on either a steam or hot water system, and generally this type of heater is provided with a temperature control device located in the boiler water circulating connection to the water heater. The setting on this thermostatic valve may be. as low as . 647 American Society of Heating and Ventilating Engineers Guide, 1936 140 F or as high as 180 F and may be readily adjusted to meet particular requirements. With this type of control it is impossible to overheat the hot water supply which is an important safety consideration in some installations. This type of system may also be conveniently used during the non-heating season with the operation of the fuel burning device controlled by the water heater thermostat. (See Fig. 10, Chapter 14.) During the heating season the water heater temperature control functions as a low limit control. When an indirect water heater is applied to a gravity hot water system, it is necessary to provide a valve in the supply to the heating system to prevent the flow of hot water from the boiler when heat is not required iii the house. This valve may be controlled from a room thermostat and the automatic fuei-burning device controlled from the water heater thermostat. To prevent circulation in a forced hot water heating system flow control valves may be installed in the flow and return lines which act merely as check valves when the circulating pump is not operating. In this arrangement the pump is controlled by the room thermostat and the automatic fuel-burning device is controlled from the water heater thermostat. . STORAGE CAPACITY AND BOILER ALLOWANCES The amount of storage provided in the hot water tank or heater is somewhat a matter of choice but is usually made ample to carry over the peak shortage which is likely to occur and is based on the assumption that only 75 per cent of the storage capacity will be available, as it has been found that if more than this amount is withdrawn from storage, the tank is so cooled down as to make the balance useless. The general rule may be cited that the less the heating capacity the greater must be the storage, and the greater the storage the less may be the heating capacity down to a point where the heating capacity will fail to be sufficient to heat up the tank storage during the periods of small load. Example 5. A heater to supply 500 persons will have an average daily use of about 500 X 40 gal = 20,000 gal and this is an average of ^^'^24 ^ = 833 gph but the peak hour will require Ho of 20,000 -- 2000 gal and the shortage.during the peak hour, if the heating capacity is made to suit the average hourly use of 833 gal, will be 2000 -- 833 = 1167 gal so that the storage capacity, based on 75 per cent being available from this 1167 capacity without cooling the tank excessively, will be -=-==- = 1556 gal. 0.75 ' Should it be desired to reduce the size of storage tanks and to use a greater heating capacity, it is only necessary to increase the heating capacity to say 1200 gph which then gives 2000 -- 1200 = 800 gal as the shortage during the peak hour, and the necessary storage will be --= 1067 gal; or the heating capacity can be increased to 1500 gal, leaving a shortage of 2000 -- 1500 = 500 gal. Good design requires that the heating capacity be made as small as possible without introducing undesirable amounts of storage, as the heating capacity directly determines the load on the source of heat. 648 Chapter 35--Water Supply Piping and Water Heating As indicated in.Example 5, the heating load is proportional to the heating capacity and the boiler capacity must be increased for higher heating capacities and may be reduced for smaller heating capacities with greater storage. It may be assumed that a boiler capacity of about 4 sq ft1 of equivalent steam heating surface (radiation) must be provided for every gallon of water heated 100 F or from 50 F to 150 F, which is the temperature rise most commonly assumed and required. On this basis it will be seen that the various conditions cited.in Example 5 will require additional boiler capacity as follows: , Heating Capacity (gph) 833 1200 1500 - . . ., Additional Boiler Capacity . (Sq Ft EDR). 3332 4800 . 6000. From this it is apparent that it is less costly to provide ample storage and to reduce boiler capacity than to diminish the storage and supply a greatly increased boiler capacity to compensate. The boiler allowance value of 4 sq ft of equivalent steam radiation for each gallon of water heated through a temperature range of 100 F is based on an hourly heating rate. When reduced heating capacities are desired for economic reasons of boiler design and selection, engineers frequently recommend that the. heating rate be extended over a period of two hours in which case the boiler allowance value would be reduced to 2 sq ft of equivalent steam radiation. Similarly any other heating rate, may be established and a corresponding value of boiler allowance deter mined. . Reliable information based upon the installations of several heaters in existing heating systems indicates varying arbitrary values of boiler allowances to be used. When these values are selected for usage, a careful analysis of the varying factors involved in determining these values should be considered so that the proper heating allowances may be provided. ESTIMATING HOT WATER DEMAND BY FIXTURES In buildings where the occupancy is doubtful and only the number of plumbing fixtures can serve as a basis for determining the probable hot water demand, the problem is not so simple owing to the- fact that a fixture gives no information as to how heavy a service may be demanded from the fixture and this amount of service is really the governing factor in making an estimate of the probable hot water demand. Table 13 may prove of some value in this respect as it gives the maximum assumed, quantity of hot water per hour which will be demanded of any fixture andthen gives a percentage of this amount which may be assumed as probable in different types of buildings. Table 14 gives approximate hot water re quirements in various types of buildings. L,.7. -----. . an apartment nouse witn zu apartments has 20 S,u 0 lavatnes, kitchen sinks and 20 laundry trays; what is the probable maxi mum hourly demand for hot water? . Actual requirement for HXMeg temperature difference ~ 100 * 8,33 = 3.33 uq ft per gallon of water heated. ' 240 , . ... . ... of andAmerican Society Heating Ventilating Engineers Guide, 1936 20 Baths at 40 galand 33 per cent._,,.................................................................................................... 270 gal 20 Lavs, at 20 galand 25 per cent__............................................ 100 gal 20 Sinks at 30 galand 33 per cent.--.................................................................................................. 200 gal 20 Trays at 50 galand 60 per cent.,,....................................................................... 600 gal Total........................ ...................... ..................................................................................................................1170 gal Probable peak use at one time.................................................................................... v.......................... 35 per cent Probable actual peak demand......................................... ......................................................................... 409 gph If three persons are assumed to an apartment the total daily use of hot water should approximate 20 X 3 X 40 gal = 2400 gal and if the peak hour is 10 per cent of this ' amount, the peak hour by this method shows a probable demand of one-tenth of 2400 gal, which indicates that the values in Table 13 are safe. SWIMMING POOL HEATING REQUIREMENTS Swimming pools present a-problem of hot water heating demand which is frequently overestimated. Few outdoor swimming pools require water heating, and in some cases they require the addition of cold water to regulate Hie temperature. The recirculation system of a swimming pool consists of the pumps, hair and lint catchers, and filters together with all necessary pipe connections to the inlets and outlets of the pool. The water heater, the sterlizing equipment and suction cleaner are usually installed or connected to the recirculation system and may be considered as integral parts of the system. The recirculation system and all its component parts should be designed to provide the required volume of circulation so that the water turnover ratio is at least two times per day and where heavy loads are anticipated the turnover ratio should be increased to three times or .more. Many states have regulations prescribing the circulation turnover. The water heaters for swimming pools are usually instantaneous steam Table 13. Ordinary Maximum Hourly Demand for Hot Water for Various Fixtures in Gallons and Probable Percentage of Usage Trraov Buildmo Maximum Pbobablb GPH Lavatories Private Public Baths Showers Slop Sinks Kitchen Pantbt Sinks Sinks Foot Baths Wash Teats A.v. Max. Uses 20 20 40 300 30 30 20 20 50 Probable Usage in Per Gent of Maximum Ordinary Use Apt. house Ciub Gym. Hospital Hotel Industrial Laundries Office building Baths Residences Schools Y. M. C. A. 25 50 33 67 67 33 50 25 60 35 25 75 50 67 67 67 100 25 80 60. 25 100 100 100 ... .. 100 80 25 75 50 33 67 67 100 25 80 45 _25 100 50 33 , 100 67 100 25. 80. 70 25 150 100 100 67 67 _____ 100 ___ 90 25 100 . ,: 33 .... _____ 100 100 25 75 . 50 ___ 20 25 150 150 100 50 100 25 50 33 50 33 50 50 60 50 25 75 100 67 33 100 50 25 25 100 100 100 67 67 100 100 80 75 Percentage of fixtures likely to be demanding maximum probable usage at any one time. 650 r i Chapter 35--Water Supply Piping and .Water Heating roiI heaters. These heater^..should be, sized so that they will have suf ficient capacity to heat the water delivered by the circulating pump 15 F per hour. - ; ' . ' ' The water, temperature in a pooh is usually maintained at about 72 F. A few states have regulations prohibiting higher water temperatures than 70 F. The room temperature should be approximately 5 F higher, but not more than 8 F higher nor less than 2 F lower, than the water tem perature. Example 6. Assume a swimming pool 75 ft long, 30 ft wide with an average depth of 6 ft.. If the water is to be heated from a temperature of 50 to 65 F, what capacity heater and steam consumption is required with a turnover ratio of two times per day? Pool volume: 75 X 30 X 6 X 7.5 = 100,000 gal. With a turnover ratio of twice in 24 hr, the heating capacity is: = 2080 gal per hour. . " X .24 The steam consumption would be :-2--0--8--0----X----8- -3--3----(-6--5---_---S--O--')-L = 268 lb steam per hour! Regulation of swimming pool temperatures is .essential for successful operation and economy. It is therefore recommended that the steam supply to the heater be provided with' a'bypass which may be used for pool filling and initial heating and that a smaller bypass be installed with an automatic control valve having the capacity to heat the cir culation water approximately 5 F per hour. . Table 14. Hot Water Consumption in Various Types of Buildings for Different Purposes Ttfs op Building Conditions . Gallons Hotels Public Buildings Industrial Buildings Restaurants Room with basin only Room with bath (Transient) (Men) (Mixed) (Women) . Two-room suite and bath. Three-room suite and bath 10 (per day) 40 (per day) 40 (per day) 60 (per day) 80 (per day) 80 (per day) 100 (per day) . Public bath or lavatory Public shower Public lavatory with attendant 150 (per day per fixture) 200 (per day per fixture) 200 (per day per fixture) Per office employee Per factory employee Cleaning floors ... 2 (per day) ' - . 5 (per day) 3 (per 1000 sq ft per day) $0.50 Meals : $1.00 Meals $1.50 Meals 0.5 (per customer with hand washing) 1.0 (per customer with machine washing) 1.0 (per customer with hand washing) 2.0 (per customer with machine washing) , 1.5 (per customer with hand washing) 4.0 (per customer with machine washing) American Society of Heating and Ventilating Engineers Guide, 1936 PROBLEMS IN PRACTICE 1 The heating capacity of an indirect water heater is 100 gal per hour, using steam at 215 F and raising the water from a temperature of 50 to 150 F. Deter mine the heating capacity of the same water heater using water at a tem perature of 180 F for the heating medium. Using Equation lf and because the surface area of the water heater is the same for each condition, the two conditions may be equated as follows: 100 X 8.33 (150 - 50) Q X 8.33 (150 - 50) 240 [215 - <W+M] ~ 100 [l80 - m+M] Q = 28.98 gal per hour, capacity of heater using water at a temperature of 180 F. 2 Why Is it impractical to size water supply piping so pipe friction will pro duce an equal pressure on each fixture? Because the friction would be built up only in periods of maximum flow and at all other .times it would be only a fraction of that required. . 3 What is the purpose of zoning water supply systems in tali buildings? To avoid excessive pressures in the lower stories. ' 4 A Define the maximum possible flow, the maximum probable flow, and the average probable flow. The maximum possible flow is the flow which would occur if all of the outlets on the system were opened at one and the same time. The maximum probable flow is the flow which will occur with probable peak conditions. The average probable flow is the flow likely to occur under a normal condition of use. 5 What is the factor of usage? This is the percentage of the maximum possible flow Vhich is likely to occur at peak load. 6 A How many feet higher than the uppermost fixtures must the water line in a house tank be to provide about 15 lb per square inch pressure at the fixture outlet? Allowing for pipe losses, about 45 ft. 7 A What methods of hot water circulation commonly are employed with hot water supply systems? a. Upfeed risers with returns having no connections paralleling the risers. b. Upfeed risers with returns in other locations, and with connections taken off both supply and return. c. One main upfeed riser, without connections, supplying all downfeed risers for all fixtures. N: .* 8 A Which method of hot water supply generally is the most Satisfactory? The single main upfeed riser supplying drop risers for all fixtures. . 9 A How.much of the water stored in a hot water storage tank really is available for use? ' ' About 75 per cent, because when only 25 per cent of the original water remains in the tank it has been so cooled down by the entering water that it is too cold for satisfactory use. 10 A In cases of intermittent demand, does a large hot water storage tank increase or decrease the steam load for water heating? It decreases the steam load in cases of intermittent demand but causes no change in the steam load if the demand is constant. ......................................... 652 Chapter 36 INSULATION OF PIPING Heat Losses from Bare Pipes, Steam and Hot Water Lines, Low Tem perature Pipe Insulation, Pipe Sweating, Heat Losses from Pipe Surfaces, Thickness of Pipe Insulation, Underground Insulation PIPE insulation performs an important function in preventing loss of heat where steani or hot water are conveyed from one part of a building to another, and in reducing the absorption of heat by cold pipes as well as preventing condensation on the outer surfaces. BARE PIPE LOSSES Heat losses from horizontal bare iron pipes, based on data obtained from tests conducted at the Mellon Institute, are given in Table 1. These 'losses are expressed in Btu per hour per linear foot of pipe per degree Fahrenheit difference in temperature between the steam or hot water in the pipe and the air surrounding the pipe. The monetary value of the loss of`heat given in Table 1' may be obtained by means of Fig. 1 for various heating system efficiencies, temperature differences, and calorific values and costs of coal. To solve a problem, select the proper heat loss coefficient from Table 1 and locate this value on the upper left hand margin of the chart. Then draw lines in the order indicated by the dotted lines, the dollar value of the heat loss per 100 linear feet of pipe per 1000 hours being given on the upper right hand scale. In using this chart, the cost of coal should also include the labor for handling it, boiler room expense, etc. Heat losses from horizontal copper pipes based on tests at the A.S.H.V.E. Laboratory, are given in Table 21. In order to determine heat losses per linear foot of pipe from known losses per square foot, it is necessary to know the area in square feet per linear foot of pipe. Table 3 gives these areas for various standard pipe sizes while Table 4 gives the area in square feet for flanges and fittings for various standard pipe sizes. Very often, even where pipes are thoroughly insulated, flanges and fittings are left bare due to the belief that the losses from these parts are not large. However, 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 Emission from actions, Vol. 38, 1932). Iron . and Copper Pipe, by F. C. Houghten and Cari Giitberlet (A.S.H.V.E. Trans- 653 American Society of Heating and Ventilating Engineers Guide, 1936 Fig. 1.. Chart for Estimating Dollar Value of Heat Loss from Bare Iron Pipes; (See Table l)a This chart is based on 100 linear feet per 1000 hours. For fractions or multiples of .these factors, multiply by proper percentage. heat equivalent to more than a ton of coal per year shows the necessity for insulating such surfaces. STEAM AND HOT WATER LINES The conductivities of various materials used for insulating steam and hot water pipes are given in Table 5. In this table the conductivities are given as functions of the mean temperatures or the mean of the inner and 654 Chapter 36--Insulation of Piping ' Table 1. Heat Losses from Horizontal Bare Iron Pipes Expressed in Btu per linearfoot per degree Fahrenheit difference in temperature between the pipe and surrounding still air at 70 F Nominal Pin . SlZB (Inches) x X i lX m 2 2X 3 3X 4 4X 5 6 S 10 12 120 F * 50 F 0.543 0.660 0.791 0.979 1.09 1.34 1.58 1.88 2.13 2.36 2.60 2.87 3.39 4.32 5.32 6.25 Hot Water 150 F 180 F 1 227.1 F 1 (5 Lb) Temperature Difference . 80 F 0.573 0.690 0.829 1.02 1.15 1.40 1.67 1.99 2.24 2.50 2.75 3.02 3.56 4.55 5.61 6.62 110 F 0.605 0.729 0.878 1.087 1.220 1.491 1.778 2.100 2.380 2.650 2.920 3.200 3.775 5.050 5.925 6.995 140 F 0.638 0.762 0.920 1.15 1.29 1.58 1.87 2.22 2.51 2.78 3.08 3.38 4.01 5.14 6.34 7.46 157.1 F 0.656 0.781 0.953 1.184 1.335 1.637 1.937 2.301 2.585 2.873 3.170 3.493 4.115 5.270 6.551 7.670 Steam 297.7 F (50 Lb) 227.7 F 0.742 0.886 1.084 1.345 1.520 1.866 2.215 2.641 2.972 3.312 3.655 4.030 4.755 6.120 7.592 8.900 337.9 F (100 Lb) 267.9 F 0.796 0.955 1.166 1.450 1.640 2.015 2.388 2.853 3.215 3.582 3.956 4.368 5.153 6.635 8.245 9.670 Table 2. Heat Losses from Horizontal Bare Copper Pipes Expressed in Btu per linear foot per degree Fahrenheit difference in temperature between the pipe at 210 F and surrounding still air at 70 F Nominal Pipe Size * (Inches) X X i ix ix 2 Outside Diameter (Inches) 0.625 0.875 1.125 1.375 1.625 2.125 Temperature Difference 140 F 0.405 0.478 .0.550 0.623 0:695 0.841 Nominal Pipe . Size (Inches) 2X 3 3X 4 .5 6 Outride Diameter (Inches) 2.625 3.125 3.625. 4.125 5.125 6.125 Temperature Difference 140F 0.986 1.131 1.276 1.422 1.713 2.004 Table 3. Radiating Surface per Linear Foot of Pipe Nominal Pipe Size (Inches) a X 1 ix Surface Area (SqFt) 0.22 0.275 0.344 0.435 0.498 H Nominal 1 Pipe Size | (Inches) 12 3 4. ASurface rba . (SqFt) 0.622 0.753 0.917 1.047 1.178 1 Nominal Pipe Size (Inches) 5 6 8 10 12 A ^Surface rb (8q Ft) 1.456 1.734 2.257 2.817 3.338 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Table 4. Areas oe Flanged Fittings, Square Feet* Nominal Pipe Sob (Inches) 1 ix . m2 m 3 3X 4- iX 5' 6 8 10 12 Flanged Coupling . 90 Deg Ell. Long Radius Ki.l Teb Cross Standard Extra Heavy Standard Extra Heavy Standard Extra Heavy Standard Extra Standard Heavy Extra Heavy .. 0.320 0.383 0.477 0.672 0.841 0.945 1.122 1.344 1.474 1.622 1.82 2.41 3.43 4.41 0.438 0.795 0.510 0.957 0.727 1.174 0.848 1.65 1.107 2.09 1.484 2.38 1.644 2.98 1.914 3.53 2.04 : 3.95 2.18 4.44 2.78 5.13 3.77 6.98 5.20 10.18 6.71 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 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 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 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. outer surface temperatures of the insulations. This method of stating conductivities makes it possible readily to calculate the heat loss through single or compound sections. It should be emphasized that-the con ductivities given in Table 5 for the various insulations are the average of values obtained from a number of tests made on each type of material, also that 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 six of the types of insulation given in Table 5 for 1, 1J4 and 2-in.-thick materials, and for temperatures commonly encountered in engineering practice can be obtained from Tables 6 to 11, Table 5. Conductivities (k) of Various Types of Insulating Materials for Medium and . High Temperature Pipes* Mean Temperature Ttfes op Insulating Materials -. 100 F 200 F 300 F . 400 F 85 per cent Magnesia Type.............................. 0.425 Corrugated Asbestos Type.-..................... -...... 0.530 0.465 0.650 (4 Plies per 1 in. thick) Corrugated Asbestos Type............................... 0,480 0.555 (8 Plies per 1 in. thick) Laminated Asbestos Type............-----.......... 0.360 0.415 (30-40 Laminations per 1 in. thick) Laminated Asbestos Type------............... 0.545 0.605 (20 Laminations per 1 in: thick) Rock Wool Type............. .............................. --r - High Temperature Type.----....------.............. (Diatomaceous Earth,and Asbestos) Brown Asbestos Type......... -......... -................. --- (Felted Fibre) 0.350 0.515 0.600 0.410 0.545 0.640 1 0.505 0.550 0.770 0.890 0.630. 0.705 0.470 0.525 0.665 .0.725 0.470 0.530 0.575 0.605 0.675 0.715 500 F 0.590 0.585 0.785 0.590 0.635 0.750 R. H. Heilman. Mechanical Engineering, Vol. 46 (1924), p. 593. 656 a 36--. Chapter; Insulation of Piping Table 6. Coefficients of Transmission (U) for Pipes Insulated with 85 Per Cent Magnesia Type Insulation These coefficients are expressed in Blu per hour per square foot of pipe surface per degree Fahrenheit difference in temperature between pipe and surrounding still air at 70 F THICXNE8S ^or Insulation (Inches) i Nominal Pipe Size . (Inches) X H l IX \X 2 m 3 3X 4 m 5 6 8 10 12 Hot Water ' Steam 120 F 150 F 180 F 210 F- 1 227.1 F I (5 Lb) 297.7 F (50 Lb) Temperature Difference 50 F 80 F 110 FT \ 140 F: | 157-1 F 227.7 F 0.744 0.672 0.613 0.562 0.532 0.500 0.475 0.455 0.441 0.429 0.420 0.411 0.402 0.387 0.375 0.369 0.754 0.681 0.621 0.570 0.539 0.506' 0.481 0.461 0.447 0.435 0.425 0.416 0.408 0.392 0.380 : 0.374 0.764 0.689 0.629 0.577 0.546 0.512 0.487 0.467 0.452 0.441 0.431 0.422 0.413 0.397 0.385 0.378 0.774 : 0.697 0.637 0.585 0.553 0.519 0.493 0.474 0,438 0.446. 0.437 0.427 0.419 0.403 0.390 0.383 0.779 0.701 0.641 0.589 0.557 0.523 0.497 0.477 0.462 0.449 0.440 0.430 0.422 0.405 0.393 0.386 0.802 0.721 0.659 0.606 0.573 0.538 0.512 0.492 0.475 0.463 0.453 0.443 0.435 0.418 0.405 0.398 337.9 F (100 Lb) 267.9 F 0.814 0.731 0.670 0.617 0.582 0.547 0.520 0.500 0.483 0.471 0.460 0.450 0.442 0.425 0.412 0.405 14 0.617 0.625 0.633 0.642 0.646 0.665 0.676 X 0.550 0.558 0.566 0.573 0.577 0.596 0.606 1 0.496 0.503 0.511 0.518 0.522 0.540 0.549 IX ; : 0.453 0.459 0,465 0.472 0.475 0.490 0.498 tx - 0.424 0.430 0.436 0.442 0.445 0.459 0.467 .2 0.394 0.400 0.405 0.410 0.413 0.427 0.434 3X 0.371 0.376 0.382 0.386 0.389 0.401 0.408 3: 0.352 0.357 0.362 0.367 0.370 0.380 0.387 m 3X 0.339 0.343 0.347 0.351 0.354 0.364 0.370 4 0.328 0.333 0.337 0.341 0.343 0.353 0.359 iX 0.320 0.324 0.328 0.332 0.334 0.343 0.350 5 0.312 0.316 0.320 0.324 0.326 0.336 0.342 6 0.303 0.307 . 0.311 0.315 0.318 0.328 0.333 8 0.287 0.291 0.295 0.299 0.301 0.311 0.316 ; 10 0.276 0.280 0.284 0.288 0.290 0.299 0.304 12 ' 0.272 . .0.275 0.279 0.283 0.285 0.294 0.299 2 : .. I - X. -; x . .i iX IX 2 2X : 3 \ ; 3x 4, iX .5 6 8 .. 1 10 : 1 12 0.543 0.484 0.433 0.393 0.365 0.338 0.316 0.297 0.284 0.275 0.266 0.258 0.250 0.236 0.224 0.219 0.551 , 0.490 0.439 0.398 0.370 0.343 0.320 0.301 0.288 0.278 0.270 0.262 0.254 0.239 0.227 0.222 0.558 0.565 0.497 0.503 0.445 0.451 0.403 0.409 0.376 0.381 0.347 0.351 0.324 0.328 0.305 0.309 0.292 0.295 0.282 0.285 0.273 0.276 0.265 0.268 0.257 0.260 0,242 0.245 0.230 0.233 Q.225 .0.228 0.569 0.507 0.454 0.412 0.384 0.354 0.331 0.312 0.297 0.287 0.278 0.270 0.262 0.247 0.235 0.230 0.587 0.523 0.467 0.424 0.397 0.364 0.341 0.321 0.306 0.296 0.286 0.278 0.270 0.255 0.242 0.237 0.597 0.532 0.476 0.432 0.402 0.370 0.347 0.326 0.311 0.301 0.290 0.283 0.274 0.258 0.246 0.240 657 '1936American Society of Heating and Ventilating Engineers Guide, Table 7. Coefficients of Transmission (U) for Pipes Insulated with Corrugated Asbestos Type Insulation (4 Plies Per Inch Thickness) These coefficients are expressed in Btu per hour per square foot of pipe surface per degree Fahrenheit difference in temperature between pipe and surrounding still air at 70 F Thickness or Inbulation ' (Inches) i m 2 Nominal Pips Size (Inches) a % i ia 1A 2 2A 3 3a 4 *A 5 6 8 10 12 A 3A 1 i]4 2 2A 3 3A 4 *a 5 6 8 10 12 A K 1 iA \a 2' 214 3 3A 4 m 5 6 8 10 12 Hot Water 120 F | ISO F | 180 P 210 F 227.1 F (5 Lb) Steam 297.7" (50 Lb) 337.9 F (100 Lb) 50 F 0.890 0.803 0.731 0.671 0.635 0.595 0.567 0.544 0.527 0.513 0.502 0.490 0.480 0.462 0.447 0.441 80F 0.919 0.829 0.756 0.693 0.656 0.615 0.586 0.562 0.544 0.530 0.518 0.507 0.496 0.477 0.462 0.456 Temperature Difference HOP 140 F 157.1 0.949 0.857 0.780 0.716 0.677 0.635 0.605 0.580 0.561 0.548 0.535 0.523 0.512 0.493 0.476 0.470 0.978 0.883 0.804 0.738 0.698 0.656 0.624 0.598 0.578 0.565 0.551 0.539 0.528 0.508 0.491 0.485 0.995 0.898 0.818 0.751 0.710 0.667 0.635 0.608 0.588 0.575 0.561 0.549 0.538 0.517 0.500 0.493 . 227.7 267^9F 1.065 0.961 0.876 0.804 0.760 0.715 0.680 0.652 0.631 0.616 0.601 0.588 0.577 0.554 0.537 0.529 1.106 0.997 0.909 0.834 0.788 0.742 0.705 0.677 0.654 0.639 0.624 0.611 0.599 0.575 0.557 0.550 0.737 0.657 0.594 0.542 0.507 0.471 0.443 0.421 0.403 0.393 0.383 0.372 0.362 0.343, 0.328 0.323 0.762 0.679 0.614 0.559 0.524 0.487 0.458 0.435 0.417 0.405 0.394 0.384 0.374 0.354 0.339 0.334 0.787 0.702 0.634 0.577 0.541 0.503 0.473 0.449 0.430 0.418 0.407 0.397 0.387 0.366 0.351 0.346 0.812 0.725 0.654 0.596 0.558 0.519 0.488 0.463 0.443 0.432 0.420 0.409 0.399 0.378 0.362 0.357 0.826 0.737 0.666 0.606 0.568 0.528 0.497 0.472 0.451 0.439 0.428 0.417 0.406 0.385 0.369 0.364 0.884 0.790 0.713 0.649 0.609 0.565 0.533 0.506 0.483 0.471 0.460 0.447 0.436 0.413 0.397 0.391 0.918 0.820 0.740 0.673 0.632 0.587 0.553 0.525. 0.502 0.489 0.476 0.463 0.452 0.429 0.413 0.407 0.648 0.578 0.518 0.469 0.438 0.404 0.379 0.356 0.339 0.328 0.318 0.308 0.299 0.282 0.267 0.263 0.670 0.598 0.535 0.485 0.452 0.417 0.391 0.367. 0.350 0.339 0.328 0.318 0.309 0.291 0.276 0.272 0.692 0.617 0.552 0.501 0.467 0.430 0.403 0.378 0.361 0.350 0.339 0.329 0.319 0.301 0.285 0.280 0.713 0.637 0.570 0.517 0.481 0.444 0.415 0.390 0.373 0.360 0.350 0.340 0.329 0.310 0.294 0.289 0.726 0.648 0.580 0.527 0.490 0.452 0.422 0.397 0.380 0.367 0.357 0.346 0.335 0.315 0.299 | 0.294 0.779 0.810 0.694 0.720 0.622 0.645 0.566 0.587 0.526 0.545 .0.483 0.502 0.451 0.466 0.425 0.440 0.406 0.421 0.392 0.406 0.381 0.395 0.370 0.384 0.358 0.371 0.336 0.349 0.319 0.332 0.314.. | 0.325 658 36--Chapter Insulation of Piping Table 8. Coefficients of Transmission (U) for Pipes Insulated with Corrugated . ' Asbestos Type Insulation (8 Plies Per Inch Thickness) ; These coefficients are expressed in Btu per hour per square foot of pipe surface per degree Fahrenheit difference in temperature between pipe and surrounding still air at 70 F THICKNESS or Insulation (Inches) Nominal PtPB Size (Inches) a 3A l VA m 2 2A 3 i 3A 4 iA 5 6 8 10 12 .A % 1 m IA 2 2A 3 IA 3A 4 4'A 5 6 8 10 12 a Va i ia m 2 2A 3 2 3A 4 iA 5 6 8 10 12 120 F 50 F 0.801 0.723 0.658 0.606 0.573 0.538 0.511 0.489 0.474 0.461 0.451 0.442 0.432 0.416 0.402 0.397 Hot Water ISO F 180 F 210 F 227.1 V (5 Lb) Temperature Difference 80 F ^ HOF 140 F 157.1 F 0.820 0.739 0.673 0.619 0.586 0.550 0.523 0.501 0.485 0.472 0.462 0.452 0.442 0.426 0.412 0.406 0.838 0.756 0.688 0.633 0.599 0.562 0.534 0.512 0.496 0.482 0.472 0.462 0.452 0.436 0.421 0.415 0.857 0.773 0.704 0.647 0.612 0.575 0.546 0.524 0.507 0.493 0.482 0.473 0.463 0.446 0.430 0.424 0.868 0.783 0.713 0.655 0.619 0.581 0.553 0.531 0.514 0.500 0.489 0.479 0.468 0.451 0.435 0.429 Steam 297.7 F (SO Lb) 227.7 F 0.913 0.824 0.751 0.688 0.652 0.612 0.582 0.558 0.542 0.527 0.515 0.505 0.493 0.475 0.459 0.452 337.9 F (100 Lb) 267.9 F 0.939 0.847 0.772 0.707 0.670 0.629 0.599 0.575 0.557 0.542 0.530 0.520 0.508 0.489 0.473 0.466 0.664 0.593 0.535 0.488 0.457 0.425 0.399 0.378 0.363 0.353 0.343 0.334 0.325 0.309 0.295 0.291 0.679 0.607 0.547 0.499 0.467 0.434 0.408 0.387 0.371 0.361 0.351 0.342 0.333 0.316 0.303 0.298 0.695 0.621 0.560 0.510 0.478 0.444 0.418 0.396 0.380 0.369 0.360 0.350 0.341 0.324 0.310 0.306 0.711 0.636 0.573 0.522 0.490 0.455 0.428 0.405 0.388 0.378 0.368 0.358 0.349 0.332 0.318 0.313 0.720 0.643 0.580 0.528 0.496 0.460 0.434 0.411 0.393 0.383 0.373 0.363 .0.353 0.336 0.322 0.317. 0.759 0.677 0.611 0.556 0.522 0.485 0.457 0.433 0.415 0.403 0.393 0.383 0.373 0.355 0.340 0.335 0.780 0.697 0.629 0.572 0.537 0.499 0.471 0.446 0.427 0.415 0.404 0.394 0.383 0.365 0.350 0.344 0.585 0.520 0.465 0.422 0.394 0.364 0.339 0.319 0.304 0.295 0.285 0.278 0.269 0.253 0.240 0.236 0.599 0.533 0.476 0.432 0.403 0.372 0.347 0.327 0.311 0.302 0.292 0.284 0.275 0.259 0.245 0.241 0.613 0.545 0.487 0.442 0.412 0.380 0.355 0.334 0.318 0.308 0.299 0.290 0.282 0.265 0.251 0.247 0.627 0.635 0.558 0.565 0.498 0.504 0.452 0.458 0.422 0.427 0.388 0.393 0.363 0.367 0.342 0.346 0.326 0.330 0.315 0.319 0.306 0.310 0.297 0.301 0.288 0.292 0.270 1 0.273 0.257 0.260 0.253 1 0.256 0.668 0.595 0.532 0.483 0.450 0.415 0.387 0.365 0.349 0.336 0.327 0.317 0.307 0.288 0.275 0.270 0.688 0.612 0.547 0.497 0.462 0.427 0.398 0.375 0.358 0.345 0.336 0.326 0.315 0.296 0.282 0.277 659 A" American Society of Heating and Ventilating Engineers Guide, 1936 Table 9. Coefficients of Transmission (U) for Pipes Insulated with Laminated Asbestos Type Insulation (30 to 40 Laminations Per Inch Thickness) These coefficients are expressed in Btu per hour per square fool of pipe surface per degree Fahrenheit difference in temperature between pipe and surrounding still air at 70 F orThickness Inbulation i i .. *,,' T- IK 2 ' -! Nominal Pipe ` Size (Inches) 'K K l IK 2 2K 3 3K 4 m 5 6 8 10 12 120 F . 50 F 0.605 0.546 0.498 0.457 0.432 0.406 0.385 0.370 0.359 0.349 0:341 0.334 0.327 0.314 0.304 0.301 Hot Water 150 F 180 F 210 F 227.1 F (5 Lb) 80F. Temperature Difference 110 F 140 F 157.1 F 0.620 0.560 0.510 0.468 0.442 0.416 0.395 0.379 0.367 0.358 0.350 0.342 0.335 0.322 0.312 0.308 0.635 0.573 0.522 0.480 0.453 0.426 0.405 0.389 0.376 0.366 0.359 0.351 0.343 0.330 0.320 0.316 0.650 0.586 0.534 0.491 0.464 0.437 0.415 0.398 0.385 0.375 0.367 0.359 0.351 0.338 0.328 0.324 0.658 0.594 0.541 0.497 0.470 0.442 0.420 0.403 0.390 0.380 0.372 0.364 0.356 0.343 0.332 0.328 Steam 297.7 F (SO Lb) 227.7 F 0.695 0.627 0.570 0.525 0.496 0.467 0.443 0.425 0.413 0.402 0.393 0.384 0.376 0.362 0.350 0.346 . 337.9 F (100 Lb) 267.9 F 0.716 0.645 0.587 0.540 0.511 0.481 0.457 0:438 0.426 0.414 0.405 0.395 0.387 0.373 0.361 0.356 K K 1 IK IK 2 2K 3 3K 4 4K S 6 8 10 M2 0.502; 0.450 0.405 0.369 0.343 0.321 0.301 0.286 0.274 0.267 0.259 0.253 0.247 0.234 0.223 0.221 0.514 0.461 0.415 0.378 0.352 0.329 0.309 0.293 0.281 0.273 0.266 0.260 0.253 0.240 0.229 0.227 0.526 0.473 0.426 0.387 0.361 0.337 0.317 0.301 0.288 0.280 0.272 0.266 0.260 0.246 0.235 0.232 0.539 0.484 0.436 0.396 0.370 0.345 0.324 0.308 0.295 0.287 0.279 0.272 0.266 0.252 0.241 0.238 0.546 0.490 0.442 0.401 0.375 0.350 0.330 0.313 0.300 0.291 0.283 0.276 0.269 0.255 0.245. 0.241 0.577 0.517 0.466 0.423 0.397 0.369 0.348 0.330 0.316 0.307 0.299 0.291 0.284 0.270 0.258 0.255 0.595 0.532 0.480 0.435 0.409 0.380 0.358 0.340 0.326 0.317 0.308 0.300 0.293 0.279 0.266 0.263 K K 1 IK IK '2 2K 3 3K 4 4K 5 6 8 10 12 0.442 0.453 07464 0.392 0.402 0.412 0.352 0:360 0.369 6.319 0.327 0.335 0.297 0.304 0.311 0.274 0.280 0.287 0.256 0.262. 0.269 0.243. 0.249 0.254 0.231 0.236 0.242 0.223 0.228 0.234 0.216 0.222 0.227 0.210 0.215 0.220 0.203 0.208 0.213 0.191 0.196 0.201 . 0.182 0:187 0-1192 0.178 0.183 0.187 0.475 0.481 0.422 0.428 0.378 0.383 0.343 0.348 0.319 0.323 0.294 0.298 0.275 0.279 0.260 0.264 0.248 0.251 0.240 0.243 0.233 0.236 0.225 0.228 0.218 0.221 0.206 0.209 0:196 0.199 0.192 I 0.195 0.508 0.452 0.405 0.367 0.341 0.314 0.293 0.277 0.265 0.257 0.249 0.241 0.233 0.220 0.210 0.205 0.523 0.465 0.417 0.379 0.352 0.324 0.302 0.285 0.273 0.265 0.256 0.248 0.240 0.227 0.215 0.210 Chapter 36--Insulation of Piping Table 10. Coefficients of Transmission (17) for Pipes Insulatedwith Laminated Asbestos Type Insulation (Approximately 20 Laminations Per Inch Thickness) These coefficients are expressed in Btu per hour per square foot of pipe surface per degree Fahrenheit difference in temperature between pipe and surrounding still air at 70 F Thickness OF Insulation (Inches) i IK 2 Nominal Pipe Size (Inches) K M l IK IK 2 2K 3 3K 4 4K 5 61 8 10 12 120 F 50 F 0.910 0.823 0.748 0.686 0,649 0.610 0.581 0.558 0.539 0.524 0.514 0.503 0.492 0.473 0.458 0.452 Hot Water Steam 150 F 180 F 210 F 227.1 F (5 Lb) 297.7 F (50 Lb) Temperature Difference 80 F 110 F 140 F 157.1 F 227.7 F 0.925 0.836 0.760 0.698 0.659 0.620 0.590 0.567 0.548 0.532 0.522 0.511 0.500 0.480 0.465 0.459 0.940 0.850 0.773 0.710 0.671 0.630 0.600 0.576 0.557 0.541 0.530 0.519 0.509 0.488 0.473 0.467 0.956 0.863 0.785 0.721 0.682 0.640 0.609 0.585 0.566 0.551 0.539 0.528 0.517 0.497 0.481 0.475 0.964 0.871 0.792 0.728 0.688 0.647 0.615 0.591 0.571 0.556 0.544 0.533 0.522 0.502 0.485 0.478 1.001 0.902 0.823 0.756 0.716 0.671 0.638 0.613 0.592 0.577 0.564 0.553 0.542 0.521 0.504 .0.497 337.9 F (100 Lb) 267.9 F 1.022 0.921 0.840 0.771 0.731 0.685 0.6510.626 0.604 0.589 0.575 0.565 0.553 0.532 0.514 0,507 K X 1 IKIK 2 2K 3 3K 4 4K 5 6 8 10 12 0.755 0.767 0.780 0.674 0.685 0.697 0.607 0.618 0.628 0.553 0.562 0:572 0.517 0.527 0.536 0.481 0.490 0.499 0.453 0.460 0.469 0.429 0.436 0.444 0.412 0.419 0.427 0.400 0.407 0.415 0.390 0.396 . 0.402 0.380. 0.386 0.393 0.369 0.375 0.382 0.351 0.358 0.364 0.337 0.344 0.350 0.332 0.338 0.344 0.793 0.708 0:639 0.581 0.545 0.508 0.477 0.452 0.434 0.422 0.409 0.400 0.389 0.370 0.356 0.350 0.800 0.715 0.645 0.587 0.550 0.513 0.481 0.456 0.438 0.426 0.413 0.403 0.392 0.374 0.359 0.353 0.831 0.848 0.743 0.759 0.670 0.684 0.610 . 0.622 0.572 0.584 0.535 0.547 0.500 0.511 0.475 0.485 0.456 0.465 0.443 0.453 0.429 0.437 0.418 0.427 0.408 0.417 0.388 0.397 0.373 0.382 0.367 0.375 K X- l IK : IK 2 2K .3 3K 4 4K .5 6 8; UP 12 0.664 0.591 0.529 0.480 0.445 0.412 0.385 0.364 0..346 0.336 0.325 0.316 0.306 0.288 0.275 0.269 0.675 0.601 0.538 0.488 0.453 0.420 0.392 0.370 0.352 0.342 0.332 0.322 0.312 0.293 0.279 0.274 0.687 0.611 0.547 -0.497 0.462 0.427 0.398 0.376 0.358 0.348 0.338 0.327 0.317 0.298 0:284 0.278 0.698 0.621 0.557 0:505 0.470 0.434 0.405 0.382 0.365 0.354 0.343 0.333 0.323 0.303 0:289 0.283 0.704 0.627 0.562 0.510 0.475 0.438 0.409 0.385 0.368 0.357 0.346 0.336 0.326 0.306 0.292 0.286 0.732. 0.652 0.584 0.529 0.494 0.455 0.425 0.400 0.382 0.371 0.360 0.349 0.338 0.317 0.302 0.296 0.747 0.665 0.597 0.540 0.504 0.464 0.434 0.408 0.390 0.378 0.367 0.356 0.345 0.324 0.308 0.302 661 American Society of Heating and Ventilating Engineers Guide, 1936 Table 11. Coefficients of Transmission (U) for Pipes Insulated. with Rock Wool Type Insulation . These coefficients are expressed in Btu per hour per square foot of pipe surface per degree Fahrenheit difference in temperature between pipe and surrounding still air at 70 F Thickness of Insulation (Inches) i 2- Nominal Pipe Sob ' (Inches) - Al Vi l Wi m 2. m 3 3}4 4 5 6 8 10 12 120 F 50 F 0.631. 0.569 0.518 0.476 0.450 0.422 0.402 0.385 0.373 0.363 0.355 0.348 0.341 0.327 0.317 0.313 Hot Watsr 150 F 180 F 210 F 227.1 F. (S Lb) Temperatube Difference 80T 0.644 0.581 0.529 0.486 0.460 0.431 0.411 0.394 0.381 0.371 0.363 0.356 0.348 0.335 0.324 0.320 110 F 0.658 0.593 0.541 0.497 0.470 0.441 0.420 0.402 0.389 0.379 0.371 0.364 0.356 0.342 0.331 0.327 140 F 0.672 0.606 0.552 0.507 0.480 0.450 0.428 0.411 0.398 0.387 0.379 0.371 0.363 0.349 0.338 0.334 1571 * 0.680, 0.613 0.559 0.513 0.485 0.456 0.434 0.415 0.402 0.392 0.383 1 0.376 0.368 0.353 0.343 0.338 Steak 297.7 K (50 Lb) 227.7 F 0.712 0.642 0.585 0.537 0.508 0.478 0.455 0.4350.421 0.4110.402 0.394 0.386 0.372 0.360 0.355 337.9 F (100 Lb) -- 267.9 F 0.730 0.659 0.600 0.551 0.522 0.490 0.466 0.446 0.432 0.422 0.413 0.404 0.396 0.381 0.369 0.364 XA %A 1 ni m 2 m 3 3H 4 4)4 5 6 8 10 12 A 3A l m 2 VA 3 3% '4 4)4 5 6 8 10 12 0.523 0.468 0.421 0.383 0.359 0.333 0.314 0.296 0.286 0.278' 0.270 0.263 0.257 0.244 0.235 0.230 0.534 0.477 0.430 0.391 0.366 0.340 0.320 0.302 0.291 0.284 0.276 0.269 0.262 0.249 0.240 0.234 0.461 0.471 0.409 0.418 0.366 0.374 0.333 0.340 0.310. 0.316 0.286 0.292 0.268 .0.274 0.252 0.257 0.241 0.246 0.232 0.237 0.225 0.230 0.218 0.223 0.213 0.217 0.200 0.204 0.189 0.193 0.185 0.190 0.545 0.487 0.440 0.399 0.375 0.348 0.327 0.310 0.298 0.290 0.282 0.275 0.267 0.254 0.245 0.239 0.481 0.427 0.382 0.347 0.323 0.298 0.279 0.262 0.251 0.242 0.235 0.228 0.221 0.208 0.197 0.194 0.556 0.497 0.449 0.407 0.383 0.356 0.335 0.317 0.304 0.296 0.287 0.280 0.273 0.260 0.250 0.245 0.491 0.436 0.390 0.355 0.330 0.304 0.285 0.268 0.257 0.247 0.240 0.233 0.226 0.213 0.201 0.198 0.563 0.503 0.455 0.412 0.387 0.360 0.339 0.321 0.307 0.300 0.291 0.284 0.277 0.263 0.253 0.247 0.496 0.441 0.395 0.359 0.334 0.308 0.289 0.272 0.260 0.250 0.243 0.236 0.228 0.215 0.204 0.200 0.590 0.528 0.477 0.433 0.407 0.378 0.355 0.337 0.323 0.315 0.305 0.298 0.290 0.276 0.265 0.260 0.520 0.463 0.415 0.377 0.351 0.323 0.302 0.284 0.272 0.262 0.255 0.247 0.239 0.225 0.214 0.210 0.606 0.542 0.490 0.444 0.419 0.389 0.365 0.347 0.332 0.323 0.313 0.305 0.297 0.283 0.272 0.267 0.534 0.475 0.427 0.387 0.360 0.331 0.310 0.292 0.280 0.269 0.262 0.253 0.245 0.231 0.220 0.216 Chapter 36--Insulation of Piping nrlusive. The loss through other thicknesses of the materials, and for ot. L0t water or steam temperature conditions may be obtained by Semolation The heat loss coefficients given in Tables 6 to 11 are ! qc,,j on the conductivities in Table 5 and were computed from data given in Chapter 22, The Guide 1931. LOW TEMPERATURE PIPE INSULATION `Surfaces maintained at low temperatures should be insulated so as to retard the flow of heat from the outside into the low temperature area and ' to orevent the formation of condensation and of frost if the temperatures are low enough, as well as to prevent corrosion induced by the presence of condensed moisture on metal surfaces. Materials commonly used for insulating pipes and surfaces at low temperatures are cork, rock cork, hair felt and other felted or fibrous non-absorbent materials. Thermal conductivities of low temperature insulating materials are given m . Chapter 5. . . Insulating materials are available commercially to meet varying tem- oerature gradients. For example, the thickness of insulation for ice water is approximately llA in- if the temperature in the line is not lower than 25 F the thickness of insulation for brine is approximately 2y2 in. where the temperature ranges from 0 deg to 25 F; and the thickness of insulation where the brine temperature ranges from --30 F to zero degrees is ap . proximately 4 in. Insulation to Prevent Freezing If the surrounding air temperature remains sufficiently low for an ample period of time, insulation cannot prevent the freezing of still water, or of water flowing at such a velocity that the quantity of heat carried in the water is not sufficient to take care of the heat losses which will result and cause the temperature of the water to be lowered to the freezing point. Insulation can materially prolong the time required for the water to give up its heat, and if the velocity of the water flowing in the pipe is maintained at a sufficiently high rate, freezing may be prevented. Table 12 may be used for making estimates of the thickness of insula tion necessary to take care of still water in pipes at various water and surrounding air temperature conditions. Because of the damage and service interruptions which may result from frozen water in pipes, it is essential that the most efficient insulation be utilized. This table is based on the use of hair felt or cork, having a conductivity of 0.30. The initial water temperature is assumed to be 10 deg above, and the sur rounding air temperature 50 deg below the freezing point of water (tem perature difference, 60 F). The last column of Table 12 gives the minimum quantity of water at initial temperature of 42 F which should be supplied every hour for each linear foot of pipe, in order to prevent the temperature of the water from being lowered to the freezing point. The weights given in this column should be multiplied by the total length of the exposed pipe line expressed in feet. As an additional factor of safety, and in order to provide against temporary reductions in' flow occasioned by reduced pressure, it is advisable to double the rates of flow listed in the table. It must be 663 American Society of Heating and Ventilating Engineers Guide, 1936 emphasized that the flow rates and periods of time designated apply only for: the conditions stated; To estimate for other service conditions the following method of procedure may be used. . ; : ! If water enters the pipe at 52 F instead of 42 F, the time required to cool it to the freezing point will be prolonged to twice that given in the table, or the rate of flow of water may be reduced so that the quantity required will be one-half that shown in the last column of Table 12. However, if the water enters the pipe at 34 F it will be cooled to 32 F in one-fifth of the time given in the table. It will then be necessary to in crease 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 Table 12. Data for Estimating Requirements to Prevent Freezing of Water in Pipes Pipe Size (Inches) , . `' H l m 2 3 .4 . .5 6 8 10 12 1 0.42 0.83 1.40 1.94 3.25 4.55 5.92 7.35 10.05 13.00 15.80 to Cool Water to Freezing Point. ' ' . to Prevent Freezing, Pounds per Linear Foot of " . . Pipe per Hour . 2 0.50 1.02 1.74 2.48 4.27 6.02 7.96 9.88 13.90 18.10 22.20 - Thickness of Insulation In Inches "3 * - 0.57 1.16 2.02 2.90 5.08 ' 7.20 9.69 12.20 17.25 22.70 28.10 0.54 0.68 0.84 6.95 1.24 . 1.47' 1.73 1.98 2.46 2.96 . 3.43 . 2. 0.45 . 0.55 0.68 0.75 0.94 , 1.11 \ 1.29 1.46 1.78 2.12 2.46 3\ 0.40 0.48 0.58 0.64 0.79 0.93 1.06 1.19 1.44 1.70 1.93 freezing point will be 60/80 of the time given in the table, or the necessary quantity of water to be supplied will be 80/60 of that given. . In making calculations to arrive at the values given in Table 12, the loss of heat stored in the insulation, the effect of a varying temperature dif ference 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 12, the only safe way to insure against freezing is to install a steam or hot water line, or to place an electric resistance heater along the side of the exposed water line. The heating system and the water line are then 664 ' Chapter 36--Insulation of Piping insulated so that the heat losses from the heating system are. not exces sive, and the heating effect is concentrated against the water pipe where it is needed. For this form of protection 2 in. of an efficient insulation may be applied. Fig. 2. Thickness of Pipe Insulation to Prevent Sweating* *Solve problems by drawing lines as indicated by dotted line, entering chart at lower left hand scale. Pipe Sweating In some cases the prevention of condensation rather than the con servation of heat is the governing factor in determining the thickness of insulation required. Fig. 2 may be used for determining the thickness of any material of known conductivity which should be used to prevent con densation on pipes and flat metallic surfaces. The surface resistances used for calculating the family of curves in Fig. 2 are based on the results of; tests made on canvas-covered pipe insulation surfaces at Mellon Institute. 665 v::' . . ` American Society of Heating and Ventilating Engineers Guide, 1936 Chapter 36--Insulation of Piping However, it has been found that the resistance for asphaltic and roofing surfaces is practically the same as for canvas surfaces, so that the curves given may be followed with no alteration for surfaces commonly used. ' Moisture will be deposited on a surface whenever its temperature falls to that of the dew point. The maximum permissible temperature drop is indicated on Fig. 2 at the point where the guide line passes through the horizontal scale at the left center of the chart. This temperature drop represents the difference between the dry-bulb temperature and the dew point temperature for the conditions involved. (See discussion of con densation in Chapter 7.) 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 shown for bare surfaces, because of the fact that air flowing over the surface of the insulation can increase only the rate of heat transfer from surface to air, and cannot change the internal resistance to heat flow inherent in the insulation itself. The maximum increase in loss due to air velocity ranges from about 30 per cent in the case of 1-in. thick insulation, to about 10 per cent in the case of 3-in. thick insulation, provided 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 sealed as tightly as possible. Pipe insulation out-of-doors should be provided with a waterproof jacket, and other outdoor insulation should be thoroughly weatherproofed. , ECONOMICAL THICKNESS OF PIPE INSULATION Table 13 shows the thicknesses of insulation which ordinarily are used for various temperature conditions. Where a thorough analysis of economic thickness is desired, this may be accomplished through the use of the chart, Fig. 3. The dotted line on the chart illustrates its use in solving a typical example. 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 temperature difference; thence vertically to the line representing the conductivity 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 per cent return on the investment; thence horizontally, to the right, to the curve representing the given pipe size; thence vertically to the scale at the top right margin where the economical thickness may be read,off directly. . Underground Insulation Underground steam distribution lines are carried in protective struc tures of various types, sizes and shapes. (See Chapter 37.) Detailed 667 American Society of Heating and Ventilating Engineers Guide, 1936 Table 13. Thicknesses of Insulation Ordinarily used Indoors* Steam Pressures . (Lb Gags) ob Conditions - 0 to 25 25 to 100 100 to 200 Low Superheat Medium Superheat High Superheat Degrees Fahrenheit 212 to 267 267 to 338 338 to 388 388 to 500 500 to 600 600 to 700 Thickness or Insulation Pipes Larger Than 4 In. Pipes 2 In.to 4 In. 1 in. 1 A in. 2 in. 2^2 in. 3 in. 3K in. 1 in. 1 in. 1 A in . . 2 in. 2)4 in. 3 in. Pipes Hln. to iH lu* 1 in. 1 in. - 1 in. in. 2 in. 2 in. All piping located outdoors or exposed to weather is ordinarily insulated to a thickness Yt in. greater than shown in this table, and covered with a waterproof jacket. Table 14. Thickness of Loose Insulation for Use as Fill in Underground Conduit Systems Steam . Pressures or Conditions Temperatures Fahrenheit Minimum Tbickness 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 Minimum Distance Between Steam AND Return Hot Water, or 0 to 25 212 to 267 DA 2 2A 25 to 125 267 to 352 2 2A 3 Above 125, or superheat 352 to 500 2^ 3 3A lA i 1A 1A iA i A data on commonly used forms of tunnels and conduit systems have been published by the National District Heating Association Pipes in tunnels are covered with sectional insulation to provide maximum thermal efficiency and are also finished with good mechanical protection in the form of metal or waterproofing membrane outer jackets. 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. dif ficult of accurate determination due to the many variables which have to be considered. As a result of theories developed by J. R. Allen*, together with experimental data presented by others, the usual endeavor is to secure not less than 90 per cent efficiency for underground piping. Table ^Handbook of the National District Beating Association, Second Edition, 1932.. . .. . . . ' Theory of Heat Losses from Pipes Buried in the Ground, by J. R. Allen (A.S.fl.V.E. Transactions, Vol. 26. 1920). . 668 Chapter 36--Insulation of Piping 14 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 Yi im less in thick ness than that determined by the use of Fig. 3. Fig. 3 is based on con ditions of insulation exposed to the air, whereas normal ground tempera ture is substituted for air temperature in determining the temperature difference for use with the chart when applying it for underground pipe line estimates. PROBLEMS IN PRACTICE 1 What precautions must be taken in selecting insulation used for covering pipe lines carrying materials at temperatures lower than the dew point? Materials intended for this service should be as moisture proof as possible and in addition an outer covering should be applied which is proof against diffusion of air and water vapor. If the material permits the diffusion of air, the air will reach a point in the covering where the temperature is below the dew point. The condensed water will ' gradually accumulate until the covering becomes saturated, which will increase the conductivity and perhaps lower the mechanical strength of the covering until it becomes worthless. 2 Compute the total annual heat loss from 165 ft of 2-in. bare pipe in service 4000 hours per year. The pipe is carrying steam at 10 lb pressure and is exposed to an average air temperature of 70 F. The pipe temperature is taken as the steam temperature, which is 239.4 F, obtained from Table 6, Chapter 1. The temperature difference between the pipe and air = 239.4 - 70 = 169.4 deg. By interpolation of Table 1 between temperature differences of 157.1 F and 227.7 F, the heat loss from a 2-in. pipe at a temperature difference of 169.4 deg is found to be 1.677 Btu per hour per linear foot per degree temperature difference The total annual heat loss from the entire = 1.677 X 169.4 X 165 (linear feet) X 4000 (hours) = 188,000,000 Btu. 3 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 Question 1. If the system is operating at an over-all efficiency of 55 per cent determine the monetary value of the annual heat loss from the line. - i iimiioii mu suppncu lo cne system -- I -h 13,000 (Btu) X 2000 (lb) X 0.55 (efficiency) = $0,804. The total cost of heat lost per year = 0.804 X 188 (million Btu) = $151.15.* 4 If the steam line given in Question 1 is covered with 1-in. thick 85 per cent magnesia, determine the resulting total annual heat loss through the insula tion. Also compute the monetary value of the annual saving and the per centage of saying over the heat loss from the bare pipe. ZJLecs *7 11 " *'-'-'Fsiatuic 0.1,cicm.es Ui 1UI.1 r ana tti.i r, tne coemcient ol transmission for 1-m. magnesia on a 2-iri. pipe is found to be 0.525 Btu per nour per square foot of pipe surface per degree temperature difference at a temperature hourlyhb!e. 0.525 X 169.4 d=ef8.o9.0T4heBttout.a. lFrom Talobslsep3erthsequaarreeafpoeort olinf einasrufloaotetdopf i2p-einw. iplliptheeins in approximat* solution of this problem may be quickly made by use of the estimating chart given 669 American Society of Heating and Ventilating Engineers Guide, 1936 found to be 0.622 sq ft. The total annual loss through the insulation = 89.04 X 0.622 X 165 (linear feet) X 4000 (hours) = 36,550,000 Btu. The annual bare pipe loss as determined in the solution of Question 1 was found to be 188,000,000 Btu. The saving due to insulation is then 188,000,000 -- 36,550,000 = 151,350,000 Btu per year. From the solution of Question 2 it was found that the heat supplied to the system cost $0,804 per million Btu; therefore, the monetary value of the saving = 0.804 (dollars) X 151.35 (million Btu) = $121.69, or 81.2 per cent of the cost when using uninsulated pipe. 5 The manufacturer's list price for 85 per cent magnesia insulation is $0.36 per linear foot for 1-in. (standard thick) material to cover a 2-in. pipe. De termine the period of time required for the saving found in Question- 3 to pay for the cost of the insulation if it can be purchased and applied at 80 per cent of list price (20 per cent discount). . The applied cost of insulation = 165 (linear feet) X 0.36 (dollars) X 0.80 (net) = 47.52. Since the annual saving as found in Question 3 amounts to $121.69, the in sulation will pay for its cost in 47.52 + 121.69 = 0.3905 years; in other words, the cost will be repaid 2.56 times by the saving obtained in one heating season. 6 The conductivity of magnesia insulation is 0.455 at the mean temperature which will result under the conditions of 'Question 3. Estimate the most economical thickness of magnesia for application on the pipe when operating under the conditions which are given in the foregoing problems and when a 20 per cent return is required on the investment for insulation. ' Use chart given in Fig. 3. Begin at the left bottom margin and proceed successively as shown by the dotted line example to the following essential data which are collected from the problems previously given: . 4000 hours operation per year. _ - . $0,804 value of heat, dollars per million Btu. . 169.4 deg temperature difference. 0.455 conductivity of insulation. . 20 per cent discount from list, cost of insulation. 20 per cent fixed charges, return on investment. 2-in. pipe size. Solution of the problem by use of Fig. 3 results in a required thickness of approximately 1.05 in. The nearest commercial thickness procurable is standard thick (1H2 in.) magnesia. . (It is of interest to note that the use of Fig. 3 will generally result in solutions which, for all practical pur poses, agree closely with the specifications for thicknesses given in Table 13.) ' 7 Determine the minimum thickness of wool felt insulation having a con ductivity of 0.30 necessary to prevent condensation of moisture'on a 4-in. pipe carrying cold water at a temperature of 40 F when the surrounding air reaches maximum conditions of 90 F with a relative humidity of 90 per cent. The difference between the temperature of the pipe and the surrounding air is 90 -- 40 = 50 deg. For quick estimating purposes use the chart given in Fig. 2. Enter this chart at the lower left margin on the 90 per cent relative humidity line and proceed horizontally to the right to intersect the 90 deg air temperature line. Project a line up to the 50 deg temperature difference line, and then horizontally to the right to the intersection with the 4-in. pipe size line. From this point proceed down to intersect the 0.30 line which denotes the conductivity of the insulation. Directly opposite this point of intersection the correct thickness of insulation is read from the scale on the lower right margin. This chart solution denotes that wool felt 2.4-in. thick is sufficient to, prevent condensation. The nearest commercial thickness procurable is 2J in. For prevention of condensation as well as for protection against freezing, if the thickness determined theoretically cannot be had, it is better to apply the next greater thickness procurable rather than to use any lesser thickness because an additional factor of safety is thus obtained. 670 ^ Chapter 37 i DISTRICT HEATING Underground Steam Piping, Selection of Pipe Sises, Provision for. Expansion, Capacity of Returns with Various Grades, Pipe Con duits, Pipe Tunnels, Service Connections, Steam per-Square Foot of Heating Surface, Fluid Meters and Metering, Rates 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 and for the design of heating systems for buildings which are to be supplied with purchased steam. A complete district heating instal, lation should not be attempted without a thorough study of the entire problem by men competent and experienced in that industry. UNDERGROUND STEAM 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 the local conditions so fully control the layout that little can be said regarding it. 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 con sidered high. By the use of this method the pipe sizes are kept to a minimum with consequent 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 hour per square foot of equiva lent heating surface is a safe figure. This allows for line condensation which, however, is a small part of the total at times of maximum load. Any unusual requirements such as those for process steam should be individually 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 671 ' I,1*55S? American Society of Heating and Ventilating Engineers Guide, 1936 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, in part, upon whether or not it has been passed through electrical generating units. If it has, the pressure will be considerably lower than if live steam, direct from the boilers, is used. The advantages of low pressure distribu tion (2 to 30 lb per square inch) are (1) smaller heat loss from the pipes, (2) less trouble with traps and valves, and (3) simpler problems in pressure reduction at the buildings. With distribution pressures not exceeding 40 lb per square inch there is little danger even if the full distribution pressure should build up in the radiators through the faulty operation of a reducing valve; but with pressures higher than this a second reducing valve or some form of emergency relief is usually desirable to prevent excessive pressures in the radiators1. The advantages of high pressure distribution are (1) smaller pipe sizes and (2) greater adaptability of the steam to various operations other than building heating. The different kinds of apparatus which frequently must be served require various minimum pressures. Kitchen equipment requires from 5 to. 15 lb per square inch, 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, results in quicker and more satisfactory operation at low pressures. For laundry equipment, particularly the mangle, a pres sure of 75 lb per square inch is usually demanded although 30 lb per square inch is sufficient if the mangle is equipped with a large number of rolls and if a slow rate of operation is permissible. Pressing machines and hospital sterilizers require.about 50 lb per square inch. PIPE SIZES The.lengths of pipe, steam quantities, and initial and terminal pressures having been chosen, the pipe sizes can readily be calculated by means of the Unwin pressure drop formula. This formula, which gives, pressure drops slightly larger than actual test results, is as follows: )0.0001306 fV'L ( 1. + 36\ P = * '' ' '------------ --------- d ' ' CD where . P = pressure drop, pounds per square inch. , W = weight of steam flowing, pounds per minute. L = length of pipe, feet. . d. = inside diameter of pipe, inches. . , y = average density of steam, pounds per cubic foot.. . . ... ,, This formula is similar to. the Babcock formula given in Chapter 32. Information on provision for expansion will be found in Chapter: 34. In general, return lines when installed follow the contour of the land, and Table: 1 gives sizes of return pipes for various grades, It is evident that at points where the grade is great, smaller pipes can be installed. 672 Chapter 37--District Heating PIPE CONDUITS Conduits for steam pipes buried underground should be reasonably waterproof, able to withstand earth loads and to take care of the expan sion 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. Aiichors can be anchor fittings or U-shaped steel straps which partially encircle the pipes and are firmly bolted to a short length of structural steel set in concrete. Table 1. Capacity of Returns for Underground Distribution Systems in Pounds of Condensate per Hour Size* In. 1 IK IK 2 3 4 5 6 8 ID 12 6' 448 1740 2700 4980 13900 30900 54800 90000 190000 344000 555000 r 998 2490 4190 7380 22500 44800 79800 138000 277000 498000 798000 Pitch op Pipe peb 100 Ft. V 1890 3990 5740 10700 30900 64800 120000 187000 404000 724000 1148000 3' 2240 4880 7480 13900 37400 79700 144800 237000 508000 900000 1499000 5' 3490 6480 9480 16900 50400 105000 195000 312000 660000 1190000 1990000 10' 5490 9480 14500 24900 74800 154000 294000 449000 938000 -- . 20' 7490 13500 20900 36900 105000 229000 418000 -- *Size of pipe should be Increased if .it carries any steam. In laying out conduits of this type the following points should..be,*, borne in mind: : ' 1. An expansion joint, offset, or bend should be placed between each two anchors. 2. If the distance between buildings is 150 ft or less and the steam line contains highpressure steam, the line may be anchored in the basement of one building and allowed to expand into the basement of the second building. If the steam line contains low-pressure steam (up to 4-lb pressure), this method may be used if buildings are 250 ft or less apart. 3. If the distance between buildings is between 150 ft and 300 ft and the steam line contains high-pressure steam, the lines should be anchored midway between the buildings and allowed to expand into the basements of both buildings. If the steam line contains low-pressure steam this.method may be used if buildings are between 250 ft and 600 ft apart. No manhole is required at the anchor, and a blind pit is all that is necessary. 4. For longer lines, manholes must be located according to judgment and depending: upon the expansion value of the type of expansion joint or bend that is used. The' minimum number of manholes will be required when an expansion bend or an anchor with double expansion joint is placed in each manhole and the pipes are anchored mid way between manholes. 5. A proper hydrostatic test should be made on the assembled line before the insula tion and the top of the conduit are applied. The hydrostatic pressure should be one- and-one-half times the maximum allowable pressure and it should be held for a period of at least two hours without evidence of leakage. In any, case the pressure should be no less than 100 lb per square inch. ' The styles and construction of conduits commonly used may be classi fied as follows. Some of the more common forms are illustrated in Fig, 1. Wood Casing: The pipe is enclosed in a cylindrical casing usually having a wall 4 in. thick and built of segments which are bound together by a wire wrapped spirally around 673 American Society of Heating and Ventilating Engineers Guide, 1936 the casing. The casing is lined with bright tin and coated with asphaltum. The pipe is supported on rollers carried in a bracket which fits into the casing. The lengths of casing are tightly fitted together with a male and female joint. This form of conduit is illustrated in Fig. 1 at A. The casing rests on a bed of crushed stone with tile drains laid below. The tile drains are of 4-in. field tile or vitrified sewer tile, laid with open joints. Filler Type: The pipes are supported on expansion rollers properly supported from the conduit or independent masonry base. The pipes are protected by a split-tile conduit, and the entire space between the pipes and the tile is filled with an insulating filler. Thus the pipes are nested and the insulation between them and the tile effectively prevents circulation of air. The conduit is placed on a bed of gravel or crushed rock from 4 to 6 in. thick, which is extended upward so as to come about 2 in. above the parting lines of the tile. A tile underdrain is placed beneath the conduit throughout the entire length and is connected to sewers or to some other point of free discharge. At B and D in Fig. 1 are shown two forms of tile conduit of the filler type. Circular Tile or Cast-Iron Conduit: The pipes are carried on expansion rollers sup ported on a frame which rests entirely on the side shoulders of the base drain foundation. HOUXMT Ce; (fl Fig. 1. Construction Details of Conduits Commonly Used The pipes are protected by a sectional tile conduit, scored for splitting, or a cast-iron conduit, both being of the bell and spigot type. The conduit has a longitudinal side joint for cementing, after the upper half of conduit is in place, so shaped that the cement is keyed in place while locking the top and bottom half of the conduit together with a water-tight vertical side joint. The cast-iron conduit has special side locking clamps in addition to the vertical side joint. The entire space between the conduit and the pipes is filled with a water-proofed asbestos insulation. The conduit is supported on the base drain foundation, each section resting on two sections of the base drain, thus inter locking. The base drain is so shaped that it provides a cradle for the coqduit, resting solidly on the trench bottom and providing adequate drainage area immediately under the conduit. The underdrain is connected to sewers or some other point of free discharge. For tile conduit the base drain is vitrified salt glazed tile and for cast-iron conduit it is either extra heavy tile or cast-iron. A free internal drainage area is also provided to carry away any water that may collect on the inside of the conduit from a leaky pipe or joint in the conduit. Broken stone is filled in around the base drain and up to the vertical side joint. The broken stone is covered with an asphalted filter cloth to prevent sand from sifting through the broken stone and clogging the drainage area of the base drain. The tile conduit is made in 2-ft lengths and the cast-iron conduit in 4-ft lengths, cast in 674 Chapter 37--District Heating seoarate top and bottom halves. Special reinforcing ribs give the cast-iron conduit ample strength with minimum weight. Insulated Tile Type: The insulating material, diatomaceous earth, is molded to the inside of the sectional tile conduit. The space between the pipes and the insulating con duit lining may also be filled with insulation. The pipes are carried on expansion rollers supported on a frame which rests on the side shoulders of the base drain foundation. This type of conduit has the same mechanical features as those described under the heading Circular Tile or Cast-Iron Conduit. Sectional Insulation Type (Tile or Cast-Iron): Each pipe is insulated in the usual way with any desired type of sectional pipe insulation over which is placed a standard water proof jacket with cemented joints. The pipes are enclosed in a sectional tile or cast-iron conduit as described under the heading Circular Tile or Cast-Iron Conduits. Sectional Insulation Type (Tile or Concrete Trench): A type of construction frequently used in city streets, where service connections are required at frequent intervals, the pipes are insulated as described in the preceding paragraph, and are enclosed in a box or trench made either entirely of concrete, or with concrete bottom and specially con structed tile sides and tops. The pipes are supported on roller frames secured in the concrete. At Cand E, Fig. 1, are shown two tile conduits using sectional insulation. In these particular designs the space surrounding the pifje is filled partially or wholly with a loose insulating material. The use of loose material in addition to the sectional insula tion is, of course, optional and is only justifiable where high pressure steam is used. The conduit shown at F is of a similar type and has the advantage of being made entirely of concrete and other common materials. . Sectional Insulation Type (Bituminized Fibre Conduit): Each pipe is individually insulated and encased in a bituminized fibre conduit. The insulating material is 85 per cent carbonate of magnesia sectional pipe covering, applied in the usual manner as on overhead pipes, except that bands are omitted. After every fifth section of magnesia covering there is applied a short, hollow section of very hard asbestos material in the bottom portion of which rests a grooved-iron plate carrying ball-bearings upon which the pipe rides when expanding or contracting. This short expansion section is of the same outside diameter as the adjacent 85 per cent magnesia covering. Over the pipe covering and expansion device there are placed two layers of bituminized fibre conduit with all joints staggered, and the surface of each conduit is finished with liquid cement. Conduits are placed on a bed of crushed rock or gravel, approximately 6 in. deep, and this is extended upward to about the center line of the conduit when trench is backfilled. Underdrains leading to points of free discharge are placed in the gravel or crushed rock beds. Special Water-Tight Designs: It is occasionally necessary to install pipes in a very wet ground, which calls for special construction. The ordinary tile or concrete conduit is not absolutely water tight even when laid with the utmost care. The conduit shown at G, Fig. 1, is of cast-iron with lead-calked joints and is water tight if properly laid. It is obviously expensive and is justified only in exceptional cases. A reasonably satisfactory construction in wet ground is the concrete or tile conduit with a waterproof jacket enclosing the pipe and its insulation, and with the interior of the conduit carefully drained to a manhole or sump havingan automatic pump. It is useless to install external drain tile when the conduit is actually submerged. PIPE TUNNELS Where steam heating lines are installed in tunnels large enough to provide walking space, the pipes are supported by means of hangers of 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. On account of their relatively high first cost as compared with smaller conduits, walking tunnels are sometimes not installed where provision for the heating lines is the only consideration, but only where they are required . 675 American Society of Heating and Ventilating Engineers Guide, 1936 to accommodate miscellaneous other services or provide underground passage between buildings. , SERVICE CONNECTIONS Most district heating companies enforce certain regulations regarding the consumer's installation, partly to safeguard their own interests but principally to insure satisfactory and economical service to the consumer. Fig. 2. Connections for Reducing Valves of Size Less than 4 Inches 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. Chapter 37--District Heating 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. Fig. 4 shows a typical installation used for high pressure steam service. The first reducing valve, usually furnished by the utility company, Pressure reducing valve At least 12 (eet of pipe Service valve Fig. 4. Customer's work starts here Note.- All valves, fittings, and traps up to and including customer's control valve to be at least equal to American Standard 175 lb S. S. P. Pipe to be standard weight. Continuous-flow type float trap Steam Supply Connection when Using Condensation Meter effects the initial pressure reduction. The second reducing valve, usually furnished by the customer, reduces the steam pressure to that required. 1. Provision should be made for conveniently shutting off the steam supply at night and at other times when heat is not needed. It has been thoroughly demonstrated that a considerable amount of heat can be saved by shutting off steam at night. Although there is, in 1 Return main Fig. 3. Connections for Reducing Valves of Size 4 Inches and Larger, and for Expanded Valves Figs. 2 and 3 show typical service connections used for low pressure steam service. As shown in Fig. 2, no by-pass is'used around the reducing valve on sizes less than 4 in. Fig. 3 illustrates the use of a by-pass<around reducing .valves 4 in. and larger. This latter construction permits the 676 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 shlft-off at night in most buildings even in very 677 In s ta ll Service Pressure a n d Low Pressure Reducing Va/ves F i g . 6 . T y p ic a l S e r v ic e n s t a l l a t io nI American Society o/Heating and Ventilating Engineers Guide, 1936 Chapter 37---District Heating cold weather without endangering plumbing. It is necessary, however, to have an ample amount of heating surface so that the building can be uickly 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 building with stores or restaurants on the first floor which are open in the evening, a separate main supplying the first floor will permit the steam to be shut off from the remainder of the building in the late afternoon. The 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. 2. Residual heat in the condensate should he salvaged. This heat may be salvaged by means of a cooling radiator, or as is more frequently done, by a water heating economizer (see Fig. 5) which pre heats the hot water supply to the building. Fig. 6 shows a typical steam service installation for high pressure steam, complete for steam flow metering, water heating, preheating, automatic heating control, and for using steam for other purposes. The condensation from the heating system, after leaving the trap, passes through the preheater on its way to the meter. The supply to the hot water heater passes through the preheater, absorbing heat from the condensation. If the hot water system in the building is of the recircu lating type, the recirculating connection should be tied in between the preheater and the water heater proper, not at the preheater inlet, because the recirculated hot water is itself at a high temperature. The number of square feet of heating surface in the preheater should be approximately equal to one per cent of the equivalent square feet of heating surface in the building. 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 condensation if storage capacity is provided for the preheated water. Frequently a type of preheater is used in which the coils are submerged in a storage tank. 3. Heat supply should be graduated according to variations in the outside temperature. - This may be done in several ways, as by the use of thermostats of various types or by orifice systems. Another method which is very simple is the use of an ordinary vacuum return line system in which the pressure in the radiators is varied between a high vacuum and a few pounds pres sure, thus producing some control over the heat output. One form of con trol which appears to be well suited for controlling district steam service to a building is the weather compensating thermostat. It regulates the steam supply automatically according to the outdoor temperature, and gives frequent short intervals of intermittent steam supply, and at the same time insures delivery of steam to all the radiators. Another form of regulation, known as the time-limit control, is sometimes employed for regulating the steam supply from the central station main to the building. Such a control provides an intermittent supply of steam to the radiators either throughout the 24- hours of the day or during the day- 679 American Society of Heating and Ventilating Engineers Guide, 1936 time hours only. The setting of a switch may provide no service, con tinuous service, or periodic service. For the latter, by means of several intermittent settings, steam will be supplied during each period in in crements of a certain number of minutes for each successive setting of the switch, steam being shut off during the balance of the period. These settings afford from 15 to 80 per cent of the maximum heating effect required on days of zero temperature. A night switch with a variety of settings may be adjusted so as to maintain throughout the night the intermittent supply called for by the day switch setting, or may be set to interrupt the Operation of the day switch and entirely cut off the supply of steam to the radiation at night during certain hours which are selected by the operating engineer. FLUID METERS No one thing has contributed more to the advancement of district heating than the perfection of fluid meters, which may be classified as follows: ' .. 1. Positive Meters: The fluid passes in successive isolated quantities--either weights or volumes. These quantities are separated from the stream and isolated by alternately filling and emptying containers of known capacity. 2. Differential Meters: The fluid does not pass in isolated separately-counted quan tities but in a continuous stream which may flow through the line without actuating the primary device of the meter. In the differential meter, the quantity of flow is not determined by simple counting, as with the positive meter, but is determined from the action of the steam on the primary element. Additional subdivisions of these two general classifications can be made as follows: . Positive - quantity Fluid Meters Quantity - Current - Turbine Differential Rate of flow Area (Geometric) Venturi I Flow nozzle Orifice Pitot tube ( Orifice and plug Cylinder and piston Head area (Weir) f V-notch \ Special notch 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. 3i Location of the meter. 4. Large or small quantity to be measured. 5. Temporary or permanent installation. . ' 680 37--Chapter District- Heating Pressure reducing vaIve Note - AD valves, fittings, and traps up to and including customer's control valve to be at least equal to American Standard 175 lb S. S. P. Pipe to be standard weight Vents and loops unnecessary where meter is 5 feet or more below pipe. Pipe size K1 K2 X Y 3' 3" 1- 6' 6' 4" 4" 2f 3i6" 8' 6'- 6" 3' 6:6" 12" Fig. 7. Orifice Meter Steam Supply Connection ' 6. Cleanliness of the fluid to be measured. 7. Temperature of the fluid to be measured. 8. Accuracy expected. 9. Nature of flow: turbulent, pulsating, or steady. 10. Cost. (0) Purchase price. (1) 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 of 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 combination, of meters. 17. Use as a check meter. . 18. Its facilities for determining or recording information other than flow. Condensation Meters . The majority of the meters used by district heating companies in the sale of steam to their customers are of the condensation or'flow types. , The condensation meter is a popular type for use on small and medium sized installations, where all of the condensate can be brought to a com mon point for metering purposes. Its simplicity of design, ease in testing, accuracy at all loads, low cost, and adaptability to low pressure distri bution has made it standard equipment with many heating companies... Two types of condensation meters are in general use: the tilting bucket meter and the revolving drum or rotor meter of which, there are several makes on the market. Condensation meters should not be operated under 681 of andAmerican Society Heating Ventilating Engineers Guide, 1936 pressure; they are made for either gravity or vacuum installation. Con tinuous flow traps are necessary ahead of the meter if a vented receiver is not used. Where bucket traps are used, a vented receiver before the meter is essential. If desirable a receiver may be used with a continuous flow trap, but this is not necessary. Steam flow meters are available in many types and combinations, as indicated in the subdivision covering fluid meters on page 680. The orifice and plug meter is one in which the steam flow varies directly as the area of the orifice. The vertical lift of the plug, which is proportional to the flow, is transmitted by means of a lever to an indicator and to a Chapter 37--District Heating 3. The meter body should be placed at a lower-level than that of the pressure differ - ential medium. Special instructions are furnished where the meter body is above. 4. Meter piping shpuld 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. .; STEAM PER SQUARE FOOT OF HEATING SURFACE The following factors are used in New York City for the different classes of buildings listed. The factors are based on maintaining an inside terii- pencil arm which records the flow on a strip chart. The total flow over a given period is obtained by measuring the area by using a planimeter on the chart and applying the meter constant. Fig. 7 shows a typical orifice type meter connection and indicates typical requirements in the installation of this type of meter. Fig. 8 illustrates a gravity installation using a vented receiver ahead of the meter, while Fig. 9 shows a vacuum installation without a^naster trap. Flow meters using an orifice, Venturi tube, flow nozzle, or Pitot tube as the primary device are made by a number of manufacturers and can be obtained in either the mechanically or electrically operated type. The electric flow meter makes it possible to locate the instruments at some distance from the primary element. Flow meters employing the orifice, Venturi tube, flow nozzle or Pitot tube should be so selected as to keep the lower operating range of the load above 20 per cent of the capacity of the meter: This is desirable for accuracy as the differential pressure at light loads is too small to properly actuate the meter. A few general points to be considered in installing a meter of this type are: . 1. It is desirable to place the differential medium in a horizontal pipe in preference to a vertical'one, where either location is available. ' r 2. Reservoirs should always be on the same level and installed in accordance with the instructions of the meter company. ' 682 Fig. 9. Vacuum Condensation Meter Installation without Master Trap ' 1 perature of 70 F for certain hours, with a minimum outside temperature of 0 F and an average of 43 F for the heating season of eight months (October 1 to June 1).. In this group are six types of buildings: . . Manufacturing or commercial loft type where steam is used to heat the premises during the day hours to maintain 65 to 68 F from 9 a.m. to 5 p.m. No Sunday or holiday use and no night use. Factor: 325 lb per square foot of heating surface per season. Office buildings using steam during daylight hours to maintain 70 F from 9 a.m. to b p.m. for approximately 240 days (heating season). No night use. Factor: 400 lb per square foot of heating surface per season. ' Office buildings using steam during day hours and at night when required to 7, 8 and "PTM- (customary where there are stock brokers or banking offices), 240 days. Factor: ouu lb per square foot of heating surface per season. 1 Residences of the block type (not detached) where high-class heating service is re quired; somewhat similar to apartment buildings. Factor: 550 lb per square foot of beating surface per season. , ' 683 American Society of Heating and Ventilating Engineers Guide, 1936 . Apartment houses where, high-rclass heating service is required. (Steam off at mid night;) Factor: 650 lb per square foot of heating surface, per season. ' .' - Hotels (commercial type) where very: high-class service is required: for 24 hours. Factor: 800 lb per square foot of heating surface per season. .i ; By assuming one square foot of equivalent heating surface for each 100 cu ft of space heated, which seems a fair ratio in New York City, it is possible roughly to estimate the steam- required per cubic foot of space, information which is often more easily obtained than the square feet of heating surface. Additional data on the heating 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 based 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. The profit need not be divided proportionately among the rate groups, but should be established from a competitive stand point. District heating rates should be designed to produce a sufficient return on the investment regardless of weather conditions, although existing rate schedules do not conform with this principle. Lastly, the rate schedule must be reasonably easy for the intelligent layman to comprehend. ' Depreciation should be based on a careful estimate, of the life of various elements of the property. Appropriations, to reserves should be made, with generosity in good years and with discretion in less favorable years. Glossary of Terms . Load Factor. The ratio, in per cent, of the average load to the maxi mum load. This is usually based oh 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 hour per square foot of surface. Diversity Factor.: The ratio:of the surn of the individual demands of a number.of buildings: to.the actual! compositedemand of the group. .. . r. . . o Types of Rates '' ' A. Flat Kates. ': ' . -l:- Radiator surface charge. Obsolescent B. Meter Rates.. : \ . 1. Straight-line. \ 2. Step.' Obsolescent. - " .. 3. Block. .. , - (a) `Class rates. ; .............. V C`. ^DemandKates.' v . 1.. Flat demand. 2. Wright.-. . - . .;. " 3. Hopkinson. 4. Doherty (or Three charge). . '. y-! .684 Chapter 37--District Heating Co r . Straight-Line Meter Rate. The price, charged per unit is constant, and the consumer pays in direct proportion to his consumption without regard to the difference in costs of supplying the individual customers. .... Bloch Meter Rate. The pounds of steam consumed by a customer are divided into blocks of M pounds each, and lower rates are charged for each successive block consumed) This type of charge predominates in steam heating rate schedules for it has the ad vantage of proportioning the bill according to the consumption 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 load factor (relatively high demand). The utility company must maintain sufficient capacity to serve the high demand customers and the cost of the increased plant investment is divided equally, among the users, so the high demand customers are benefited at the expense of the others. . Demand Rates. These refer to any method of charge based on a measured maximum load during a specified period of time. ' - The flat demand rate is usually expressed in dollars per M lb 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 flow 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) A charge based upon the demand, either estimated or measured; . (ft) A charge based upon the amount of steam consumed. . : . This rate may be modified by. dividing the quantities of steam demanded and consumed into blocks charged for at different rates. . . .. Demand rates are comparatively new and are not yet widely used; though 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, cus tomer, and consumption groups through the use of some modification of the Hopkinson rate. - '; 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 M lb 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. ; REFERENCES Pipe Line Designfor Central Station Heating, by B. T. Gifford (A.S.H.V.E. Transactions, Vol. 17,1911). Engineering and Cost Data Relative to the Installation of Steam'Distributing Systems in a Large City, by F. H. Valentine (A.S.H.V.E. Transactions, Vol. 22, 1916). :- - Transmission of Steam in a Central Heating System, by J. H. Walker (A.S.H.V.E. Transactions, Vol. 23. 1917). Efficiency of Underground Conduit, by G. B. Nichols (A.S.H.V.E. Transactions, Vol. 23,1917). Economical Utilization of Heat from Central Plants, by N. W. Calvert and J. E. Seiter (A.S.H.V.E. Transactions, Vol. 30, 1924). Standard Connections for Condensation Meters, (N.D.H.A. Proceedings, Vol. XII, pp. 63-76). ' Installation and Maintenance of Steam Meters, (N.D.H.A. Proceedings, Vol. XIII, pp. 177-183). . - Inaccuracy in Flow Meter Calculations, (N.D.H-A. Proceedings, Vol. XIII, pp. 183-193). Testing of Steam Meters, {N.D.H.A. Proceedings, Vol. XIV, pp. 272-276). - * -' * . -* Meter Accuracy Guarantees, (N.D.H.A. Proceedings Vol. XIV, pp. 276-277). . ' -Effect of Pulsations on the Flow of Gases, (N.D.HJl. Proceedings, Vol. XIV, pp. 277-281).' ` - Meier Connections, (N.D.H.A. Proceedings, Vol. XX, pp. T26-I43). . Layout for Testing Meters, (N.D.H.A. Proceedings, Vol. XX, pp. 391-392). Characteristic Meter Calibration Curves (N.D.H.A. Proceedings, Vol. XX, pp. 444-453). Rates (N.D.H.A. Handbook, 1932, Chapter 10). . .. _ . _ . 685 1936American Society of Heating and Ventilating Engineers Guide, PROBLEMS IN PRACTICE 1 What is the common method of determining the size of mains in a dis tribution 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 maximum estimated amount of steam may be transmitted without exceeding this pressure dif ference. The steam's velocity is disregarded and it may reach a magnitude in excess of 35,000 fpm which is not considered high. 2 a. What are the advantages and disadvantages of a low pressure distribu tion system? b. High pressure? o. The advantages of a low pressure-distribution system include: 1. Smaller heat loss from the pipes. 2. Less trouble with traps and valves. . 3.. Simpler problems with pressure reducing equipment at the buildings. 4. No danger to building heating equipment from high pressure through failure of the reducing valves. The disadvantages of a low pressure system are: 1. Larger pipe sizes. 2. Decreased field of usefulness owing to small pressure range. b. The advantages of a high pressure system are: .1. Smaller pipe sizes. - . 2. Greater adaptability of the steam to various uses other than building heating. The disadvantages of a high pressure system are: 1. Large heat loss from the pipes. 2. The high pressure traps and valves, required often give more trouble than low pressure traps and valves do. ' 3.. Extra heavy fittings are required, 4. Usually two reducing valves or some form of emergency relief is necessary to protect the building piping system. ` . 3 Determine the size of pipe from the following data using Unwin's formulas Length of pipe, 600 ft. Steam to be carried, 90,000 lb per hour, dry saturated. Initial pressure, 100 lb per square inch, gage. Final pressure, 40 lb per square inch, gage. , Using the formula: . (>+)0.0001306 W'L P= yd* The pressure drop P = 100 -- 40 = 60 lb' per square inch. The weight of steam per minute W 90,000 60: 1500. The.length of pipe in feet L = 600. . The average density of steam y in pounds per cubic foot, taken from Keenan's Table: At 100-lb gage, y = 0.2578 .. , At 40-lb gage, y = 0.1285 Average, y = 0.1932 The diameter of the pipe in inches = d. 686 37Chapter --District Heating Substituting the values in the formula: 0.0001306 X 1500s X 600 ( 1 + 60 = 0.1932 X d* d = 7.35 in. Therefore, an 8-in. pipe should be used. -4 What points should be borne in mind when laying out an underground steam conduit? , ` The conduit-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 the 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. 5 What is considered the proper pressure for a hydrostatic test before com pleting the conduit? In the case of any underground piping which is to-be buried or otherwise made inacces sible, the assembled lines shall first be tested hydrostatically.at a pressure of one and onehalf times the maximum allowable service pressure and held for a period of at least two hours without evidence of leakage. . In any case the hydrostatic pressure should not be less than 100 lb per square inch. 6 i What factors should be considered before determining the route of a steam line?. . . 1. The line should be so located that it will bring in the greatest revenue (or supply the most steam) with the least cost. . 2. The ultimate length and size of services and branches necessary with each possible location should be estimated, for mains should be run near to the big loads. 3. The location of the boiler room or piping center of present and future buildings to be served should be considered. . 4. Where possible, make the lines straight between manholes. 5. Avoid such obstructions as other lines, sewers, ducts, curb drains, manholes, valve boxes, catch basins, fire hydrants, and poles; especially avoid electric ducts and water lines. 6. Avoid locating lines near where pile driving and foundation construction for new buildings will take place. 7. Consider construction difficulties such as traffic, hard rock, and wet earth, which increase time and labor. ' 8. Consider the economies of using available sidewalk vaults of buildings. Weigh the advantage of less excavation against the cost of obstruction removal. 9. Consider all operating difficulties. 10. Consider the difficulties of negotiating agreements for lines on private property where public and private rights-of-way are available. 11. Consider the effect of proposed municipal and other improvements. 12. Consider municipal regulations. 7. State the advantages and disadvantages of tunnels over conduits. The.advantages of pipe tunnels over conduits are: 1. Accommodation for miscellaneous services other than steam. - 2. Provision of an underground passage between buildings. - 3. Easy installation of additional pipes and easy replacement of existing pipes with larger sizes. 4. Easy inspection and maintenance of pipes. 687 American Society of Heating and Ventilating Engineers Guide, 1936 The disadvantages of pipe tunnels over conduits: are: 1. Higher first cost. 2. Higher maintenance cost in general. ., - ... 8 # Is the steam consumption less in a building that shuts off its steam at night than in one that does not? Why? . . .. It has been thoroughly demonstrated that the steam consumption is less in a building where the steam is shut off at night. Although there is, in some cases, an increased con sumption 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. ; ; ... 9 # Is the condensate from a: building supplied With purchased steam always discharged to the sewer? . . : . -' . No. In some cities where the customers arc not spread over too wide a territory and where natural water conditions make the treatment of boiler feed .water expensive, the steam company provides mains for the return of the condensate to the boilers. 10 # What are the common methods for salvaging heat in condensate? The most common methods are: .. : ' . 1. The use of a water heating economizer for preheating the hot water supply to the building. . ... . 2. The use of a cooling radiator. . . .... 11 # What are the common means used to graduate the heat supply according to variations in outside temperature? .! . . . .. a. A weather compensating thermostat regulates the steam supply automatically accordiiig^ to the outdoor temperature, arid gives frequent short intervals of inter mittent steam supply; at the same time it irisures delivery of steam to all the radiators. b. Another method which is very simple is the use of an ordinary vacuum return line system in which the pressure in the radiators is varied between a high vacuurn and a ' few pounds to produce some control over the heat* output. . c. The use of an orifice system graduates heat supply. ' ' d. The time-limit control which may be set to provide no service, continuous service, or periodic service, is also used. For periodic service, steam may be supplied during each period in increments of a certain riiirribef of miriutes for each successive setting of the switch, steam being shut off during the balance of the period. This type of service is provided by. several intermittent settings. A night switch will maintain the intermittent day setting, or interrupt the day operation and cut off the supply of . .steam at night during any desired hours. .. '. . '\ '` -` 688 : --- 1...... - I. .... .........^ . . . Chapter 38 RADIANT HEATING Physical and Physiological Considerations, British Equivalent Temperature, Control of Heat Losses, Methods of Application, Principles of Calculation, Mean Radiant Temperature, Measure ment of Radiant Heating . - HEATING for comfort; is generally 'understood to mean that heat must be supplied to control the rate of heat loss from the human body .so that the physiological reactions are conducive to a feeling of comfort in the individual.. While in convection heating, as described in Chapter 30, heat is transferred from a. heating unit to the air and thence to the occupant, the primary object of radiant heating is to warm the occupant directly without heating the air to^ any extent Thus, the difference between convection heating and radiant heating is partly physical and partly physiological. ..... . Comfort requires that heat be removed from the body at the same rate as it is generated by the oxidation of the foodstuffs in the body tissues. The normal rate of heat production in a sedentary individual is about 400 Btu per hour1, or, since the entire surface area of an average adult is 19.5 sq ft, about 20.5 Btu per square foot per hour. Conditions should be such as to remove heat at this rate if the surface is to be maintained at the mean normal surface temperature of the human body. T Heat is transferred from any warm, dry body to Cooler surroundings principally by convection and by radiation, the approximate total rate of . heat loss being the sum of the two. Where the body surface is moist there is additional loss of heat through evaporation from both the body surface and the respiratory tract. .... , The rate of heat loss by conyection.depends upriri the difference between the temperature of the body arid that of tlie surrounding air, and on the rate of air motion; over the body. The loss by radiation depends entirely upon the difference between the temperature of the body and the mean surface temperature of the surrounding walls and objects. This latter temperature is called the mean radiant temperature (M RT). Because these two types of heat loss.act in a supplementary manner toward, each other, a required rate of heat loss can be secured by having a .relatively low air temperature and a relatively high MRT, or vice versa.. Thus, if the air is reduced front a given temperature to a. lower temperature, the amount of heat lost from the body by convection is increased, and this , An<! Moisture Losses from the Human Body and Their Relation to Air Conditioning Problems, 1929) C` Houghten*'W* w* Teague, W, El Miller, and W, P, .Yanf-CA:S.H;V. Transactions, Vol. 35. 689 American Society of Heating and Ventilating Engineers Guide, 1936 increase can be compensated for by raising the MRT. Similarly, with a higher air temperature the same total heat loss will be maintained by a correspondingly lower MRT. The loss by evaporation depends on the air temperature, air movement, and humidity; it is increased if the humidity is reduced. For the usual conditions of heating by radiators or convectors, where the air tempera ture ranges from 70 F to 73 F, approximately 75 per cent of the total heat loss of 400 Btu per hour occurs by radiation and convection, and the balance, or 100 Btu per hour, occurs by evaporation. In the case of radiant heating, if the air temperature is reduced to 60 F, 84 per cent of the 400 Btu per hour, or 336 Btu per hour, is lost by radiation and con-, vection, and 64 Btu per hour are lost by evaporation. The mean normal surface temperature of the human body, taken over the whole' area, including not only the exposed skin surface but also sur faces of the clothes and the hair, has been very extensively used as 75 F, particularly in British literature. However, results obtained by Aldrich2 in rooms in which the air and wall surface temperatures were approxi mately 72 F gave mean values nearer to 83 F than to 75 F. The mean body surface temperature which will maintain the optimum heat loss by radiation and convection in a uniform environment of 72 F may be' calculated from fundamental equations for radiation and natural convection by substituting a comparable cylinder for the body. Heilman* gives the following equations: a - 0.1723 .[(^)4-(^)4] (I) where 1 \0.2 / 1 \ 0.181 / \ 1.266 ( d) x(rJ *(rs-ra) ' . (2) Ht = heat loss by radiation, Btu per square foot per hour. Hc = heat loss by convection, Btu per square foot per hour. 2a = absolute temperature of the body surface, degrees Fahrenheit. Tv, = absolute temperature of the walls, degrees Fahrenheit. Fa = absolute temperature of the air, degrees Fahrenheit. ,I,m------T--b---+2 ra . . D = diameter of cylinder, inches. t = the ratio of actual emission to black body emission. . If it be assu*med that a normal adult has an average height of 5 ft 8 in. and an average body surface area of 19.5 sq ft, the surface of his body will have the same area as that of a cylinder 5 ft 8 in. long with a diameter of 13.15 in. The value of e for skin and clothing is practically 0.95. Ta and Tv, are each taken as 72 F, or 532 Absolute. The sum of H, and Hc is taken to be 15.4 Btu per square foot per hour, which is derived as the normal rate of heat loss due to convection and radiation from a sedentary individual by dividing his total sensible heat loss by his area. Solution of . *A study of Body Radiation, by L. B. Aldrich (Smithsonian Miscellaneous Collections, Vol. 81. No. 6. December, 1928). . `Surface Heat Transmission. by.R. H. Heilman (Tram. A*S.M.E., Fuels and, Steam Power Section, Vol. 51, No. 22, September-December. 1929). : 690 Chapter 38--Radiant Heating Eauations 1 and 2, using average figures as outlined, gives a value of -approximately 83 F for the normal temperature of the body surface. This agrees more closely with the values obtained by Aldrich than with the 75 F used by British investigators. British Equivalent Temperature ; The British Equivalent Temperature BET is the temperature of aii environment which is effective in controlling the rate of sensible heat loss from a sizable black body in still air when the body has a maintained surface temperature of 83 F. The BET is, therefore, a function of both the air temperature and the mean radiant temperature. Its numerical value in a uniform environment (walls and air at the same temperature) is equal to the temperature of the walls and air. In a non-uniform environ ment (walls and air at different temperatures) the BET is equivalent to that of a uniform environment in which an 83 F surface loses sensible heat at the same rate as it does in the non-uniform environment. As originally defined, the BET was based on a body surface temperature of 75 F, but 83 F has been accepted as giving results more nearly conforming with American practice4. The higher the BET the less the heat loss from the body, the rate of loss in still air being approximately proportional to the difference between the BET and the mean body surface temperature. If the BET were '83 F, there could be no sensible heat loss from a surface at that temperature, so the temperature of a normal body surface would have to rise to a point where the heat generated in the tissues could be dissipated. When convected heat is used, the temperatures of the air and walls are nearly the same, and the optimum value of the BET from the physio logical point of view is 72 F. Under these conditions the mean surface temperature of a normal body would have the optimum value of 83 F because the rate of heat loss by radiation and convection would be 15.4 Btu per square foot per hour and that by evaporation 5.1 Btu per square foot per hour, which would just balance the rate of heat production of 20.5 Btu per square foot per hour. This BET of 72 F in a uniform environment is exactly equivalent to the effective temperature of 66 F as defined by the American Society of Heating and Ventilating ' Engineers (see Chapter 3), because, in a uniform environment, a drybulb temperature of 72 F in still air with a relative humidity of 30 per cent gives an effective temperature of 66 F, which has been determined to be the optimum. METHODS OF APPLICATION There are two general methods of applying radiant heating, as follow: 1- By warming the interior surfaces of the building. Pipe coils are embedded in the concrete or plaster of the walls, ceiling or floors, the heating medium being hot water or, in some cases, steam. This has the effect of warming the entire concrete or plaster surface in which the pipes are embedded. Since the temperature of the heating medium should not exceed about 120 F on account of the possibility of cracking the plaster, the -r. " er> < . wicdauiiug me i-eriurniance oi L/irect rcacuators and Convectors. V"T5ms J_ Eq.uiva!ept Temperatures, by A. C. Willard, A. P. Kratz, and M. K Fahnestock (a S H V F JOURNAL, neating. Piping and Air Conditioning, July, 1933). k (A.S.H.V.E- 691 American Society of Heating and Ventilating Engineers Guide, 1936 area of the panel must be sufficient to supply the requisite quantity of heat at this low temperature. When carefully designed, this method produces coihfortable and eco nomical results. 2. By attaching separate heated plates or panels to the interior surfaces of the structure. These plates or panels are placed either in an insulated recess flush with the surface of the walls or ceiling or bolted on its face. They may be decorated as desired. As it is difficult to make an invisible joint between the edge of such a plate and the plaster, it is common to use a frame of plaster, wood, metal or composition around the panel. These plates may be placed either on the ceiling or the wall, or in some cases as a margin around the edge of the floor. If floor heating is required the temperature over the whole area.should not exceed 70 F: . If the entire warm surface is installed at one etid of the room there may be a marked difference between the BET on the two sides of a body in the room. It is usually desirable therefore that the heat be distributed at different points in the room so that no uncomfortable effects will be felt from unequal heating. PRINCIPLES OF CALCULATION The calculations for radiant heating are entirely different from those for convective heating. The purpose of the latter is to determine the rate of heat loss from the room by conduction, convection, and radiation when maintained in the desired condition; radiant heating involves,the regu lation of the rate of heat loss per square foot from the human body. The first step in the calculations for radiant heating is to ascertain the necessary mean radiant temperature (MRT); next, the size, temperature, and disposition of the heating surfaces required in the room to produce this MRT are estimated; and after this the determination of the convec tive heat is made. Mean Radiant Temperature If the whole of the interior surface of a room were at the same tempera ture, this temperature would represent the MRT. Such a condition seldom exists, however, since the actual surface temperature in any heated space having surfaces exposed to the outer air varies greatly for different sides of the enclosure. It is therefore necessary to ascertain by calculation the mean of these interior surface temperatures. The mean temperature in this sense is not the arithmetic average of the actual thermometric temperatures of the surfaces, but the temperature corresponding to the average rate of heat emission per square foot of surface. The temperature corresponding to this mean emission can be taken from Table 1. Conversely, the emission at different temperatures and also the emissivity factors can be obtained from this table. For instance, 1 sq ft of surface at 50 F will emit 104.9 Btu per square foot per hour to surroundings at absolute zero if the emissivity of the surface is 0.9. If the area in square feet of each part of the space is. multiplied by the emission value corresponding to its actual temperature, and these products are added together, the gross amount- of radiant heat discharged into the room by the wall surface per hour is obtained. This quantity, divided by the total interior surface, gives the average amount of heat coming into the room from the surface of the walls per square foot of surface per hour. Interpolating in Table 1, the total radiation from a surface at 83 F for 692 ' Chapter 38--Radiant Heating - Table 1. Total Black Body Radiation to Surroundings at Absolute Zero3 Mean Radiant Radiation in Btu per square foot per hour emitted to surroundings with a tempera ture of absolute zero by bodies at various temperatures and with emissivity factor e Boot ob' Msan Radiant Radiation in Btu per square foot per hour emitted to surroundings with a temperature of absolute zero by bodies at various temperatures and with emissivity factor e ' . atubb ' Deg Fahr e 1.00 0.95 e 0.90 ATURE 0.80 Deg Fahr 1.00 e 0.95 - t. 0.90 .e 0.80 30 35 40 45 46 47 48 49 50 51 52 53 . 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 99.3 103.5 107.6 112.1 112.9 113.9 114.8 115.6 116.5 117.5 118.4 119.4 120.2 121.1 122.1 123.1 124.0 124.9 125.8 126.6 127.7 128.6 129.6 130.5 131.6 132.5 133.5 134.5 135.5 94.3 98.3 102.4 106.5 107.3 108.2 109.1 109.9 110.6 111.6 112.5 113.4 114.2 115.1 116.0 117.0 117.8 118.6 119.5 120.3 121.4 122.2 123.1 124.0 125.0 125.9 126.8 127.8 128.8 89.4 93.2 96.8 100.9 101.6 . 102.5 103.4 104.1 104.9 105.8 106.5 107.4 108.2 109.0 109.9 110.9 111.6 112.4 113.4 114.0 114.9 115.8 116.7 117.5 118.4 119.3 120.1 121.1 121.9 79.4 82.8 86.1 89.7 90.4 91.1 91.9 92.4 93.2 94.0 94.7 95.5 96.2 96.9 97.7 98.5 99.2 99.9 100.7 101.4 102.2 102.9 103.7 104.4 105.4 106.0 106.8 107.6 1 108.4 71 72 73 74 75 80 85 90 100 110 120 130 140 150 160 170 180 190 200 210 220 250 300 350 400 450 500 550 600 -136:5 137.4 138.4 139.6 141.0 146.6 152.3 157.9 169.6 181.6 194.8 210.1 223.2 237.1 251.1 270.5 288.0 306.5 325.2 348.0 371.5 437.8 575.0 740.0 942.1 1176.0 1464.0 1791:0 2405.0 129.6 130.5 131.5 132.6 133.9 139.4 144.6 149.9 161.1 172.5 185.0 199.6 212.1 225.2 238.8 257.0 : 273.8 291.0 309.0 330.6 353.0 415.9 546.1 703.0 895.0 1117.0 1390.0 1701.0 2284.0 122.9 123.6 124.5 125.6 126.9 132.0 137.1 142.1 152.6 163.5 175.4 189.1 201.0 213,5 226.0 243.5 259.1 275.8 292.8 313.1 334.4 394.0 . . 517.5 666.0 847.5 1059.0 1318.0 1613.0 2165.0 109.3 109.9 110.6 111.7 112.8 117.4 121.9 126.4 135.7 145.4 155.9 : 168.1 178.5 189.7 201.0 216.4 -230.4 245.1 ' 260.3 278.4 297.1 350.2 460.0 592.0 753.5 941.0 1171.0 1434.0 1925.0 These factors are calculated from the formula ,/ 0.1723 X T*\ \ 100 000.000 ) 0 = total black body.radiation, Btu per square foot per hour. e -- emissivity. . T = absolute temperature, degrees Fahrenheit. . an emissivity of 0.95 is 142 Btu per square foot per hour. The difference, between 142 Btu and the average amount of heat coming into the room is the amount which will be lost per square foot per hour by radiation from a body at 83 F. If a rate at which it is desired that heat be lost from the body by radiation and convection be assumed, the mean radiant emission from the walls required to give the desired result can be determined from Table 1, as can also the required air temperature for the corresponding convective effect. .. The determination of the amount of radiant heating surface needed in , a room requires knowledge of the climate, the type of structure, the type of heating, and the surface temperature of the walls. This problem can be solved only on an empirical basis. After some experience, however, 693 ' American Society of Heating' and Ventilating Engineers Guide, 1936 it is possible to estimate these variables with a considerable degree of accuracy for any climate or construction. Assume that a mean radiant temperature of 65 F is desired. Table 1 shows that with all the walls at this temperature, and with an emissivity of 0.95, the gross heat emission is 124 Btu per square foot per hour. The total emission of radiation into the room from that surface would there fore be A X 124, where A is the total inside area of the room. This is the desired emission. If the whole area be divided into a number of different parts which are each at a uniform temperature--au <h, a3,--and each is multiplied by the value of the heat emission corresponding to that temperature, and if all these products are added together, their sum will represent the total actual emission of radiation into the room at these temperatures without the aid of any hot surface. .. The difference between the desired emission and the actual emission represents the additional heat which must be supplied by the hot surface. The temperature of the proposed hot surface must then be selected, and its emission-per square foot at that temperature determined from Table 1. This emission is divided into the additional amount of heat needed, ad justed for the fact that the heating units will shield the walls behind them, and the quotient obtained will be the area of the required heating surface. . It is evident that this method of calculation is approximate, and depends for its accuracy on a correct estimate of the ultimate surface temperatures attained by the actual wall surfaces. It is necessary also to calculate how much heat will be given off by the same surfaces by convection, and thereby to determine whether this amount of convected heat will warm entering ventilating air to the tem perature maintained. If it will not, additional convection surfaces must be introduced to make up the deficiency. * MEASUREMENT OF RADIANT HEATING Convection heating, having as its object the raising of"the air tempera ture to a specified degree, must be measured by thermometric methods which indicate essentially the air temperature, and not the rate of heat loss from the human body. Radiant heating, having as its object the control of the rate of heat loss from the human body, can be measured only by methods'-which basically are calorimetric, that is, which measure directly the rate of heat loss from an object maintained at the temperature of the body, irrespective of air temperature. ' The apparatus for this purpose consists, essentially of a hollow'sphere, or cylinder, containing a-fluid which can be maintained accurately at 83 F (the accepted mean surface temperature of the .human body), with an accurate means of measuring the rate of heat, supply required to maintain the temperature at that exact point. The latter measurement can be made with sufficient accuracy by electrical methods.. Although a BET of 72 F is desirable, the mean radiant and air temperatures may both .vary, provided the heat loss by radiation and convection from a surface at 83 F is maintained at the rate of 15.4 Btu per square foot per hour, ' 694 Chapter 38--Radiant .Heating which corresponds to 15.4 3.415 = 4.5 watts per square foot of exposed surface. .. This instrument, the eupatheoscope, can readily be adapted as a thermo stat by electrical control to shut off or turn on heat when the critical temperature of 83 F in the vessel is increased or decreased. A modifi cation of the instrument is called the eupatheostat. - Another instrument for maintaining comfort conditions is at present available only in a model adapted to British practice as it is designed for a temperature of 75 F. It consists of a blackened copper sphere of approxi mately 6 in. diameter in which is housed a cylindrical sump containing a volatile liquid. In operation, a small electric heating coil drawing about .5 watts creates in the sphere a vapor pressure which is constant as long as the heat losses from the sphere are standard. If the temperature of the air. or the MRT becomes too high for comfort, a greater pressure is created, owing to a smaller loss of heat from the sphere. This increase of pressure acts, on a diaphragm and shuts off the supply of heat to the room. For testing work, the globe thermometer is a very useful instrument. It consists of an ordinary mercury thermometer, with its bulb placed in the center of a sphere from 6 in. to 9 in. in diameter, usually made of thin copper and painted black. The temperature thus recorded is termed the ' radiation-convection temperature. EXAMPLE Example 1. The surface areas, temperatures, and emissions for a-room having a volume of 5760 cu ft are given in Table 2. The figures for temperatures are fairly representative of American practice with well-built walls, and are based on an emissivity of 0.95 which approximates that of most paints and building materials. Table 2. Surface Areas, Temperatures, and Emissions for a Room of 5760 Cu Ft External Wall...................... Glass....................................... Inner Wall............................ Ceiling.................................... Floor................. ............ ,......... Area So Ft Assumed Surface Temperature (Deo Fahb) 297 279 . 480 480 480 . 50 45 55 55 55 Heat Emission (Btu Per So Ft per Hour) 110.6 106.5 115.1 115.1 115.1 Total Heat Emission - from Area (Btu per Hour) 32,850 29,710. 55,250 55,250 55,250 Total.............................. 2016 228,310 e 228 310 The mean radiant temperature of the room is 2016 '' 113.2 Btu per square foot per hour which, as seen from Table 1, corresponds to an MRT of 53 F for an average emissivity of 0.95. For an average individual having a body surface of 19.5 sq ft, under conditions of comfort with a body surface temperature of 83 F, the heat given off by radiation' may be determined.by means of Equation 1 as 217 Btu per hour, or 11.1 Btu per square foot per hour. This corresponds to an environmental emission of 142 -- 11.1 = 130.9 Btu per_ square foot ,per hour, and, according to Table 1, to an MRT of 72 F. * If this body be placed in the room described, it will lose heat at the rate of 19.5 (142 -- 113.2) = 562 Btu per hour. This loss is 345 Btu per hour, or 17.7 Btu per square foot per hour, more than the rate of heat loss for comfort, which is only 19.5 (142 -- 130.9) = 217 Btu per hour. ' 695 American Society of Heating and Ventilating Engineers Guide, 1936 In order to determine the amount of radiating surface necessary to maintain the MRT at 72 F, assume the surface, temperature of the hot plates to be installed to be 200 F, which is approximately the temperature they would have -if heated by steam. The 2016 sq ft total area of the surfaces of the room multiplied by 130.9, which is the emission in Btu-per square foot per hour necessary to maintain a body surface-tempera ture of 83 F, gives a total desired .emission of 263,890 Btu per hour. It is necessary to supply ` enough" radiant-heating, surface to increase the total actual mean radiant heat emission by the room from 228,310, as shown in Table 2, to the 263,890 Btu desired. The additional heat needed is the difference between these figures, or 35,580. Btu. Since, from Table. 1, the emission per square foot at 200 F is 309 Btu, the required radiant heating surface needed is = 115 square feet. The effect of this surface suitably placed would be to raise immediately the mean radiant temperature to the required degree and to maintain it at that value as long as the surfaces remained at the values assumed. .- . ... . .. ... In the solution of this particular example, the radiation loss from the human body was selected as 217 Btu per hour, which is that taking place under optimum comfort conditions, with a body surface temperature of 83 F in a uniform environment at-72 F.. The mean radiant temperature necessarily was 72 F. If the optimum BET of 72 deg Fahr is desired, an air temperature of 72 F also must be maintained. If it is desired to maintain a lower air temperature than this, a mean radiant temperature greater than 72 F must be selected and the radiation loss from the in dividual must be recalculated from Equation 1. The calculation may be simplified by preparing tables showing, at the usual temperatures, the area of hot surface required to bring each square foot of actual wall surface at various temperatures up to a general standard of from 60 F to 70 F. It would then be necessary only to multiply the respective areas by the appropriate factors, and to add the results, to obtain the required total. . ... ., . : REFERENCES ;. -. . Room Warming by'Radiation, by A. H. Barker (A.S.H.V.E. Transactions, Vol. 38, 1932). ... : : Panel Warming, by L. J. Fowler (A.S.H.V.E. Transactions, Vol. 36, 1930). Calculations for Radiant Heating, by T. Napier Adlam (Heating and Ventilating, October, 1931). i .' . . 4 ,,, Principles of Calculation of Low Temperature Radiant Heating, by A. H. Barker tProceedings of The Institution of Heating and Ventilating Engineers, London, Vol. 30, 1931). ... Application of the Eupatheoscope for Measuring the Performance of Direct Radiators and Convectors in Terms of Equivalent Temperatures, by A. C. Willard, A. P. Kratz and M. K. Fahnestock (A.S.H.V.E. Transactions, Vol. 39, 1933). ... What will be the Future ^Development of Heating and Air Conditioning, by W. H. Carrier (Heating, Piping arid Air Conditioning, January, 1933). Method of Installing the Panel Heating System in the British. Embassy Building CHeating, Piping arid Air Conditioning, July, 1934). v Panel. Heating, by C. M. Oates .(Proceedings of Institution of Heating arid Ventilating Engineers, London, Vol. 30, 1931). ' . '. ' , Notes on Electric Warming with Special ;Reference to Low Temperature Panel Systems, by R. Grierson {Proceedings of Institution of. Heating and Ventilating Engineers, London, Vol. 28,1929). -. Radiant Heat, by A. F. Dufton {Proceedings of Institution of Heating and Ventilating Engineers, London, Vol. 30, 191). . , . .: .. . Radiant Heat, by A. F. Dufton (Proceedings of Institution of Heating and Ventilating Engineers, London, Vol. 31,1932). .' _ ' . ,- ;. Notes'on'the. Theory of Radiant Heating, by C. G.' Heys'Hallett (Proceedings of Institution of Heating and Ventilating Engineers, London,'Vol. 29, 1930). 696 Chapter 38--Radiant Heating PROBLEMS IN PRACTICE 1 Differentiate between radiant and convection heating. ' The primary function of radiant heating is to warm the individual by direct heat rays and without heating the surrounding air, while in convection heating it is generally the function of the heating medium to transfer the heat to the air and thence to the occupant of the room. 2 What is the mean normal surface temperature of the human body as determined for the United States? . 83 F. . 3 Explain the difference between radiant heating and ordinary methods of heating. .. Radiant heating. provides conditions to control the heat loss from the human body according to the physiological requirement of the body; whereas, ordinary methods of heating warm the air in a building to a predetermined temperature compatible with a feeling of comfort. " .............. .. 4 Describe how to calculate the required amount of radiant heating surface. a. Obtain the mean heat emission in Btu per square foot per hour for room surfaces X, using values given, in Table 1, and surface temperatures as shown in second column of Table 2. . b. Deduct X from 142 (142 being the emission per square foot given off by the human body at 83 F surface temperature) = Y in Btu per square foot per hour. .................. c. From (142-JIT) deduct 11.1 (11.1 being the average radiation which the human body should lose per square foot for comfort conditions) = (142-AM1-.1). = Z, :: . d. Multiply total interior surface of room by Z and divide by the emission per square foot from radiant heater, giving the surface S of radiant, heater in square feet. 5 Give a simple formula to calculate radiant heating surface required, and explain. , c _ (142 - X - 11.1) A . where B - , " S = surface of radiant heater, square feet. 142 = Heat emission, Btu per square foot per hour which the human body would give ' off at 83 F, with surroundings at absolute zero. . X = mean heat emission, Btu per square foot per hour from surfaces of room. 11-1 -- heat emission, Btu per square foot per hour from human body. . A = total surface, square feet of walls, ceilings, windows, etc., in room. B = heat emission per square foot from radiant heater surface. 6 Is the heat generated in the body affected by action? If so, does it varv greatly? J Yes. With hard work or energetic exercise, the total heat generated in the body may be five to six times that generated when it is at rest. ^ 7 When and why does the human body feel cold? ' The body feels cold not only when it loses heat at a greater rate than it can generate it but also when heat is abstracted from the body disproportionately. The human body does not require any heat from without because it generates more heat than is sufficient to maintain the correct temperature; therefore, it is only necessary to provide conditions that will maintain the correct ratio of losses. American Society of Heating and Ventilating Engineers Guide, 1936 8 a. Where did radiant heating derive its name? b. What is actually meant by radiant heating? '' . a. The term radiant heaters was introduced about 25 years ago to designate flat heating surfaces made to give off practically all their heat by radiant ether waves instead of relying on conveeted warm air. b. The term radiant heating now applies to methods of heating where, instead of heating the air to a predetermined temperature, flat heating surfaces are so placed in a room that the average virtual temperature of all wall, ceiling, floor, and glass surfaces exposed to the body is just sufficient to prevent the body's losing too much heat by radiation. The air temperature can be much cooler with radiant heating because radiation losses from the body are compensated. 9 What kind of heating surfaces are in general use? The heating units may have'flat iron surfaces heated with steam and placed under windows, or hot water pipes may be embedded in the floor, walls, or ceilings. Electrical radiant heaters are made by embedding resistance elements in porcelain or electric conductors woven into a thick paper which can be fastened to the walls or ceilings. 10 What kind of heat rays are commonly generated in radiant heating? Give examples. . All heat'rays are generally assumed to be the same as light rays; they travel at the speed of light, but they are invisible and longer. The rays used in heating are: 0.00005 to 0.0001 in. long compared with visible red rays of about 0.000027 in. . 11 t What natural evidence have we that air temperature alone is no criterion of comfort and that radiant heat affects the body more quickly? When standing in the sunshine on a coOl spring day, a person feels perfectly comfortable, but when a cloud passes over the'sun, he instantly feels much cooler as the shadow reaches him. A shielded thermometer recording the temperature of the air shows no reduction in air temperature in so short a period, so that the person actually feels a sensation of cold which an ordinary thermometer cannot register. This shows that light and heat rays are shut off simultaneously and travel at the.same speed; it also proves that radiant rays affect the comfort of the body quicker'than air temperature does. . 1. 9 698 Chapter 39 ELECTRICAL HEATING Resistors, Heating Elements, Electric Heaters, Unit Heaters, Central Fan Heating, Electric Steam Heating, Electric Hot Water Heating, Electric Hot Water Heatingfor Domestic Supply, Cooling and Reverse Cycle Heating by Electric Refrigeration, Auxiliary Electric Heating, Control, Calculating Capacities, Power Problems, ' Insulation, Electric Heating Data ' ELECTRIC heating is steadily assuming a more important place in heating, ventilating and air conditioning installations, accelerated in many territories by the load building efforts of the utilities which usually include reduced rates to encourage such installations. Electrical heating has a logical place in the heating industry because of its features of flexibility, cleanliness, safety, convenience and ease of control. Electrical heating practice has many basic principles in common with fuel heating, but there are also important differences. When heat units are delivered to each room by -wire, no combustion process is necessary, either at a central plant or at the individual room units. The maximum output of an electric heater is a fixed constant, unaffected by the temperature of the surrounding air and it follows that-the maximum total load, on an electrical heating system is the total wattage of connected electric heaters, regard less of weather conditions. The real obstacle to the more.general adoption of electric heating for buildings is the cost of the electricity itself. Because the heat units produced electrically are more costly, theirconservation is of more relative economic importance than with fuel heating, so that sponsors of electric heating give greater attention to temperature-insu lated building construction. . '. ` ; All heat is a form of energy. Fuels hold stored chemical energy which is released into.heat by combustion. Electrical-power is a forrn'of energy which can be released into heat by. passing it through a resisting material. Both fuel and electric heating have two divisions: first, the conversion of energy into heat; second, the distribution and practical use of the heat after it is produced. , In converting the chemical energy of fuels into heat by combustion, there is necessarily a considerable variation in thermal efficiency. This is not true, however, when converting electric power into heat, because 100 per cent of the energy applied in the resistor is always transformed into heat. In electric heating practice the engineer need not be concerned about efficiencies of heat production, b,ut rather about efficiencies of heat utilization. . It is the engineer's problem to distribute the electrically produced heat units in such manner as to obtain conditions of maximum comfort with the minimum consumption of electricity. .^ 699 of andAmerican Society Heating Ventilating Engineers Guide, 1936 DEFINITIONS Definitions of terms used in fuel heating are given in Chapter 44. The following terms apply particularly to electric heating: Electric Resistor: A material used to produce heat by passing an electric current through it. Electric Heating Element: A unit assembly consisting of a resistor, insulated supports, and terminals for connecting the resistor to electric power. Electric Heater: A complete assembly of heating elements with their enclosure, ready for installation in service. RESISTORS Solids, liquids, and gases may be used as resistors, but most com mercial electric heating elements have solid resistors, such as metal alloys, and non-metallic compounds containing carbon. In some types of electric boilers, water forms .the resistor which is heated by an alternating current of electricity passing through it. One of the more common resistors is nickel-chromium wire or ribbon which, in order to avoid oxidation, contains practically no iron. HEATING ELEMENTS Commercial electric heating elements are divided into open type elements, enclosed type elements, and cloth fabrics. Open type elements have resistors exposed to view. The resistors may be coils of wire or metal ribbon, supported by refractory insulation, or they may be nonmetallic rods, mounted on insulators. Open type elements are used extensively for operation at high temperatures when radiant heat is desired. They are also frequently used at low temperatures for convec tion and fan circulation heating, especially in large installations. Enclosed type elements have metallic resistors embedded in a refractory insulating material, and encased in a protective sheath of metal. Fins or extended surfaces may be used to add heat-dissipating area. Enclosed elements are made in many forms, such as strips, rings, plates, and tubes. Strip elements are used for clamping to surfaces requiring heat by con duction, and in convection and fan circulation air heaters. Ring and plate elements are used in electric ranges, waffle irons, and in many small air heaters. Tubular elements may bfi . 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. ELECTRIC HEATERS Electric heaters may be divided into three groups, conduction, radiant and convection. 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, foot warmers, soil heaters, ice melters, and . pipe heaters.- Conduction heaters are useful in conserving and localizing heat delivery at definite points. They are not suitable for general air heating. 700 Chapter 39--Electrical Heating Radiant electric heaters, which deliver most of their heat by radiation, . - have high temperature incandescent heating elements and reflectors to concentrate the heat rays in the desired directions. The immediate and pleasant sensation of warmth which is caused by radiant heat makes this type desirable for temporary use where the heat rays can fall directly Fig. 1. Portable Radiant Electric Heater Fig. 2. Radiant Electric Heater. Recessed in Wall upon the body. They are not satisfactory for general 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. The location of radiant heaters is important. They should never face a window because some rays would pass through the glass and be lost. Figs. 1 and 2 show common types of portable and wall-mounted radiant heaters. Gravity convection electric heaters, designed to induce thermal air circu-. lation, deliver heat largely by convection, and should be located and used Fig. 3. Convection Electric Heater Recessed in Wall Fig. 4. Fan Convection Electric Heater Recessed in Wall 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, enclosed to give proper stack effect to draw cold air from the floor line (Figs. 3 and 4). The flexibility possible with electric heating .elements should discourage the use of secondary .mediums for heat transfer.: Water and steam add nothing to the efficiency of an electric heater and entail expejisive construction. . . 701 American Society of Heating and Ventilating Engineers Guide, 1936 Fan convection electric heaters, which include a built-in fan unit, circu late room air over the heating elements at 300 to 400 fpm. Heaters of this type are manufactured in three designs, portable, wall hung and wall insert. The fan draws air from the floor zone through a lower grille, forces it over the heater elements and out through an upper grille into the breathing zone. The improved heating effectiveness of this type electric heater has done much to promote electric heating for residences. UNIT HEATERS Fan unit electric heaters, similar to steam unit heaters, having a pro peller type fan mounted behind the heating element, are made in many styles and can be located and used much the same as steam unit heaters Chapter 39--Electrical Heating source of heat for any given pressure as a change in air volume flowing over steam coils does not greatly affect the temperature of the delivered air. 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, being a constant source of energy... If the volume of air flow over electric heating elements is changed, and no change is made in the electrical power connections, there will be a corresponding change in the temperature of the air delivered 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 (Figs. 5 and 6). These electric unit heaters are used in industrial plants, sub-stations, power houses, pumping stations, etc., where large initial use of electricity for power purposes earns a low rate for electric heating. Portable unit heaters (Fig. 7) of this type are useful for temporary work, such as drying out damp rooms, or for warming rooms during construction. CENTRAL FAN HEATING Electric heating elements can be used for the prime source of heat in a central fan electric heating system or in the heating phase of a complete air conditioning system. They can be used in the same manner as steam served heating units for tempering, preheating or reheating the air at the main supply fan location and as booster heafters 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 evaporization of water, or for controlling air washer dew point temperatures when mounted as preheating units on the intake side of the air washer. 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 702 Fig. 7. Large Industrial Type Port able Fan Unit Electric Heater unless some compensating action is performed by cqntrol. Automatic modulation to vary the electrical heat input and synchronize it properly with the air flow has been successfully applied to central fan systems.' ELECTRIC STEAM HEATING Electric steam heating differs from fuel heating only in the use of electric boilers to generate steam. Electric steam boilers are entirely automatic and are well adapted to intermittent operation. . Small electric boilers usually have heating elements of the enclosed metal resistor type im mersed in the water. Boilers of this construction may be used on either direct or alternating current since the heat is delivered to the water by contact with the hot surfaces. To lessen the likelihood that the heating elements will burn out, they are made removable for cleaning off deposits of scale which restrict the heat flow. Large electric boilers are usually of the type employing water as the resistor. Only alternating current can - 703 American Society of Heating and Ventilating Engineers Guide, 1936 be; used, as direct current would cause electrolytic deterioration. Large boilers of this kind have electrodes immersed in. the water where heat is generated directly. Electric steam boilers are useful, in industrial plants which require limited amounts of steam for- local processes, arid for sterilizers, jacketed-vessels and pressing machines. which need a ready supply of steam. It sometimes is econorriical 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. In general, electric steam heating is confined to auxi liary or other, limited applications. If the heating system is designed to use electricity.exclusively, steam'generating or. distributing equipment is superfluous. ELECTRIC 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: However, 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 may bring electric water heating systems into general use. This type of system, known as the off-peak hot water storage heating system, offers striking possibilities in the Southern and Pacific Coast States where the degree-day heating load is low and the Utilities have developed or are now developing large blocks of hydro-electric power which can be marketed at 1 cent per kwhr or less. In this system of heating, the primary storage tank is simply a large, well-insulated, pressure type steel tank, equipped with immersion electric heating elements connected to line with automatic time switches, which also have automatic limit controls for temperature and pressure. The heating system installed in the home or other type building may be of the individual radiator type or fan-served indirect type, with provisions for the heating and humidification phases of an air conditioning system. The following types of ofTpeak heating systems are used: 1. Hot water with gravity circulation. . 2. Hot water-with forced circulation. ; : . 3. Warm air.utilizing forced circulation. 4. Unit heaters utilizing hot water as the heating medium. 5. Warm air utilizing stored heat in connection with waste heat. ' The essential parts of all types of off-peak storage systems are: . . ' ' . ' 1. Heavily insulated storage tank. - .' ' -Q . , 2. Immersion heating elements. . - 3. Automatic charging control. : . - - 4. Heat distributing system. :L ' 5. Automatic temperature control. ' ' ' - The insulated storage tank, the heating elements and the . charging control are practically identical for all types of off-peak systems.. Only the heat distributing system and the room terhperature control differ to any extent. Chapter 39--Electrical Heating The size of the storage tank is based upon the heat losses of the building, the heating schedule, the hours of heating from storage, and allowance for heating up. In, new buildings and where openings permit, factory fabricated tanks are used. Otherwise, the tanks are welded at the final location. In hot water systems, the storage tank supplies hot water to standard heating units (radiators or convectors) installed in the building. The water in the storage tank is heated to approximately 250 F. In the system using gravity circulation, the temperature of the hot water sup plied to the heating units is varied by the action of a mixing valve under control of the room thermostat. In larger installations, the circulation is obtained by means of a pump under thermostatic control. In this case, the temperature of the water supplied to the heating units is regulated by mixing the proper amount of return water with the 250 F water from the storage tank through a suitable by-pass. . The warm air system makes use of extended heating surface and a plenum chamber asserribly (i.e., a central fan system); which is usually installed .in the basement alongside the storage tank. The warm, air supply ducts are run in the usual manner from the top. of the plenum chamber to the registers in the rooms. The return air is brought back through cold air ducts to the inlet side of the fan or blower. Temperature regulation is obtained by thermostatic control of the blower and the valve admitting hot water ito the heating units. Air cleaning and humidifying apparatus is readily incorporated- in the system. Unit heaters are used in connection with off-peak storage heating systems for industrial buildings. For sub-stations and certain types of industrial buildings, the electric storage heater is used to supply hot water to unit heaters placed in various parts of the building. Certain sections of the building, such as offices and rooms which are partitioned off from the larger areas, may be heated by ducts leading from indirect heating units supplied with "hot water in parallel with the unit heaters. Warm air supplied from off-peak storage is sometimes used in con junction with a system designed to utilize waste heat. In this application, heating units are installed in the waste heat ducts, which supply waste heat from the losses of synchronous condensers and other apparatus. When the waste heat does not provide sufficient heating, the air tempera ture is boosted by supplying the proper amount of hot water from the storage tank to the heating units. Controls are provided, which not only make the entire operation automatic, but insure maximum recovery from the waste heat source. _ ELECTRIC WATER HEATING FOR DOMESTIC SUPPLY Electric water heaters of the automatic storage type for domestic hot water supply are simple and reliable, and iri many sections of the country very low electric rates have been established by the. electric utilities to secure this load. In some districts, rate schedules divide the current 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 - 705 American Society of Heating and Ventilating Engineers Guide, 1936 than average to carry over the periods when the off-peak element is timed out, without too frequent demands on the regular heating element which takes the high domestic lighting service rate. Some utilities now offer a schedule which, beyond a stipulated minimum, lowers the rate for all service if an electric water heater is installed. INDUSTRIAL ELECTRICAL HEATING , Electric heating elements have been successfully developed for in numerable industrial furnaces such as annealing, brazing, carburizing, enameling, forging, ceramic firing, hardening, metal melting, nitriding and process heating. Industrial ovens where precise control of high temperatures is necessary can be very successfully operated with electric resistance elements where temperatures as high as 700 F are required. Electric heaters for heating oil to high temperatures for secondary circu lation in process work are used as a substitute for superheated steam. Special oil can be electrically heated as high as 600 F and pumped at a pressure just sufficient to cause flow. When used in heating coils or jacketed vessels, this gives a safe and convenient automatic system for moderate-sized installations. COOLING AND REVERSED CYCLE HEATING BY ELECTRICAL REFRIGERATION1 Reversed refrigeration is frequently referred to as a heat pump since the electric motor driving the refrigerating compressor furnishes the motive power to transfer heat from one temperature to a higher temperature level. The compressor acts as a reversible refrigerating unit to extract heat from the outdoor air in winter and deliver it indoors for heating purposes, and, by a reversal, to extract heat from the indoor air in summer and discharge it outdoors. In normal use a refrigerating machine is arranged to remove heat and the heat removed is dissipated to the condenser cooling water. The driving energy is converted into heat most of which is added to the heat removed and extracted. In so-called reversed refrigeration the'heat removed together with the heat converted from the driving energy is utilized to heat the building. This conservation of the heat converted from the driving energy enables the reversed refrigeration to'show a better performance in heating service than straight refrigeration can show in cooling service. For a detailed description of this cycle see Chapter 2 on Refrigeration. H'tie Heat Pump, An Economical Method of Producing Low-grade Heat from Electricity, by T. G. N. Haldane (Electric Review, Vol. 105, p. 1161-1162, December 27, 1929, and /. E. E. Journal, Vol. 68, p. 666-675, June, 1930), House Heating by Pump with 5 to 1 Pick-up Ratio, by Gilbert Wilkes and R. . Marbury (Electrical World, Vol. 100, p. 828, December`17, 1932). .. x> . Edison Building. Heated and Cooled by Electricity, by H. L. Doolittle (Power, Vol. 74,. p. 384-351, September8, 1931). Cooling Homes, A Field for Refrigeration, by A. R. Stevenson, presented at the symposium of the Refrigeration with Gas Committee of the American Gas Association, April 20, 1926. Using the Reversed Cycle Refrigerating Principle for a Self-Contained Heating and Cooling. Unit, by Henry L. Galson (A.S.H.V.E. Journal Section, Healing, Piping and Air Conditioning, October, 1935). 700 Chapter 39--Electrical Heating AUXILIARY ELECTRIC HEATING In conjunction with heating systems of other types, an auxiliary elec trical heating arrangement is a convenient means of caring for mild days in the spring and fall which require little heat to make a house or building comfortable. Likewise, such electrical heating might be used on ab normally cold days to help out the main heating system and by this means reduce the necessary size of the system. Because of the feeling of comfort that a radiant type heater gives, bathrooms may be heated electrically with this type of heater while the rest of the house is cared for by some other system. Offices and rooms which require heat at periods when the main heating plant is shut down can be conveniently cared for electrically. CONTROL Because the efficiency of electric heat production is the same for large or small units, it is possible to reduce heat waste to a minimum by applying local heating, locally controlled: Wherever radiant heaters are used, thermostats can be used which operate through changes in air tempera ture but such thermostats can not integrate the combination effect of the radiant and convected heat. More accurate control can be had by the eupatheoscope, described in the Chapter 38 on Radiant Heating. For all convection and fan circulation heaters thermostatic control is useful. Heaters up to 5000 watts on 230 volt current can be thermostatically controlled by direct acting wall thermostats. For larger size heating elements the thermostat should operate a relay which in turn interrupts or closes the circuit to the heating element. CALCULATING CAPACITIES The methods of calculating heat losses outlined in Chapters 6, 7, and 8 may be used for electric heating exactly as for fuel heating. The total heat requirements in Btu per hour may then be converted into the electrical rating of an equivalent heating system by using the equation: Total Btu per hour . , ------------------------------- = kw rating of required electric heating (1) For comparison with steam radiation: 3415 Btu (one kwhr) 240 14.2 sq ft of steam radiation While many empirical rules based on cubic contents, floor areas, etc., are used in steam heating practice, they should never be used to deter mine size of equipment for an electrical heating installation. . For electrical heating actual heat losses should be figured accurately because the utility company rates and minimum charge items are com monly based on the size of equipment installed, so that cost of operation might be penalized by rule-of-thumb sizing of the heating equipment. ' 707 American Society of Heating and Ventilating Engineers Guide, 1936 POWER PROBLEMS The first point to determine is the cost of the power which is available for electric heating. Unlike fuels, there is no uniform cost for electric power because of the unequal cost of distribution to large and small users. The fact that electricity cannot be economically stored, but must be used as fast as it is generated, makes it impossible to operate power plants at uniform loads; hence, even the time of use may affect the cost of power. . Homes are almost universally supplied with lighting current of 115 volts, which cannot be used economically for any but the smallest heaters. Usually the service lines will not permit more than plug-in devices. The underwriters permit heaters of 1250 watts to be used from approved baseboard receptacles. Where homes have 230 volt service for cooking and water heating, and rates are favorable, larger heaters can be installed. For industrial purposes, heaters should be designed to use polyphase power, which is usually supplied at 230, 460 or 5>75 volts. All polyphase heaters should be balanced between phases. '. INSULATION , . _ - The value of building construction which incorporates built-in in sulation to reduce the outward heat loss in winter and the inward heat gain in summer has been placed in the spot light by the increasing adop tion of complete air conditioning. With electric heating, adequate insulation is very important. : Two groups of 16 homes each, in Southern California, are compared in the following actual figures taken from operating records of not less than two-years, and in some cases up to eight years. . .' . Item . Insulated Homes Uninsulated Homes Average Size of Home: Number of Rooms................. Number of Bathrooms..... ... ; Average:kw Connected Load per Home: . . - . Range!...::..:..-'."-.:.....-.!----..-.....; ! Water Heater.:.... ;............ ::: " . . Heating........... "8.7 2.6 9.6 6.3 - .. : 8.7 2.3 9.3 . 5.9 32.7 - Annual kwhr for. Heat per Home.. ............ Annual kwhr per kw Heat Connected............................ . 49.9 4562 134 47.9 ' 8223 252 Cost of Heating - If the consumer obtains heating at 2 cents per kwhr his annual cost of heating an insulated home would be $91.24, as compared with $164.46 for, heating an uninsulated home.. Thus, insulation in the average home creates an annual saving of $73.22, representing 45 per cent of the annual heating cost if the house is not insulated. . . .-. Cost of Insulatiori . ' ' . '. '. When the average cost of insulating a home is from $25.00 to $50;00 per room, or from $200.00 to $400.00 for a home of the size used herein, Chapter 39--Electrical Heating . it is therefore apparent that, savings in heating costs will pay for the cost of insulation in from 3 to 6 years. In case the insulation warrants a reduction in connected load, the subsequent reduction in installation cost of heating equipment can be applied against insulating costs which would materially reduce total cost. . ELECTRIC HEATING DATA Electric heater capacity is rated in kilowatts (kw). Electric energy is measured in kilowatt-hours (kwhr). Cost of operation = kw rating X hours used X cost per kwhr. One boiler horsepower (bhp) = 33,471.9 Btu per hour. One kilowatt-hour (kwhr) = 3,415 Btu. ~ One boiler horsepower = 33'471' 9 = 9.80 kwhr. o,415 One boiler horsepower will evaporate 34.5 lb water per hour from and at 212 F. . 34.5 One kilowatt-hour = "9^9 ~ 3.52 lb of water per hour at 212 F. Additional conversion factors are given in Chapter 44. PROBLEMS EV PRACTICE 1 Under what conditions are electric heaters most feasible? * a. In climates such as in the South and in California, where they are used economically for many heating purposes. b. As auxiliary to central steam or hot water heating plants. 1. Fall and spring. 2. During peak loads. 3. During shut-down periods. c. In factories, offices, etc., where they have a large minimum load charge for electrical power due to large size of connected motors that they cannot use up but must pay for regardless of non-use. 2 On what basis should electric heating costs be compared to heating with fuels? o. Use. b. Safety. c. Rates. . d. Locality. e. Initial investment: 1. Interest. 2. Depreciation. - ' /. Ease of serving electric heaters. g. Ease of control. . * Approximately how low must the rates be to permit the use of electricity for heating purposes? American Society of Heating and Ventilating Engineers Guide, 1936 Probably the energy must sell for 2 cents or, less per kwhr. At 2 cents the cost would be 25.86 per 1000 Mbh. (See Chapter 29 for comparison with other fuels.) This looks high, but the seasonal energy consumption would not be as large with electricity as with other fuels, for reasons stated in Question 1. 4 In fan heating systems, what is an important difference between a steam heated coil, and an electrically heated coil? A coil supplied with steam at constant pressure will remain .at constant temperature regardless of the amount of air passing over it. The temperature of the electric coil supplied with a constant amount of energy will rise if the air quantity is decreased and fall if the air quantity is increased. Chapter 40 air conditioning for industrial PROCESSES Moisture Content and Regain, Typical Industries Requiring Air Conditioning, Classification of Problems,' Control of Regain, Control of Rate of Chemical Reaction, Control of Rate of Bio chemical Reaction, Control of Rate of Crystallisation, Conditioning and Drying, Atmospheric Conditions Required, General Require ments, Air Conditioning of Libraries, Greenhouse Heating IN the manufacture or processing of hygroscopic materials such as textiles, paper, wood, leather, tobacco and foodstuffs the temperature and relative humidity of the air have a marked influence upon the rate of production and upon the weight, strength, appearance and general quality of the product. This influence is due to the fact that most materials of vegetable or animal origin, and to a lesser extent minerals in certain forms, take moisture from or give it up to the surrounding air. In industries where the physical properties of the product affect value, the question of moisture is of special importance. With increase in , moisture content, hygroscopic materials ordinarily become softer and more pliable. Standards of regain are firmly fixed in trade with fair penalties for excesses. Deficiencies result in loss of revenue tp seller and loss of desirable quality to buyer. Manufacturing economy therefore requires that the moisture content be maintained at a percentage favorable to rapid and satisfactory manipu lation 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. In the processing of hygroscopic materials, it is usually necessary to secure a final moisture content suitable for the goods as shipped. Where the goods are sold by weight, it is proper that they contain a normal or standard moisture, content. ., MOISTURE CONTENT AND REGAIN . The terms moisture content and regain refer to-the amount of moisture in hygroscopic materials. Moisture content is the more general term and refers either to free moisture (as in a sponge) or to hygroscopic moisture .. (which varies with atmospheric conditions). It is usually expressed as a - 711 American Society of Heating and Ventilating Engineers Guide, 1936 Table 1. Regain of Hygroscopic Materials Moisture Content Expressed in Per Cent of Dry Weight of the Substance at Various Relative Humidities--Temperature, 75 F Classi fication Material Description Relative Humiditt--Per Cent Authority 10 20 30 40 50*. 60 70 80 90 Natural Textile Fibres Cotton Cotton Cotton Wool Silk. Linen Linen. Jute Hemp > lea island--roving 2.5 3.7 4.6 5.5 6.6 7.9 9.5 11.5 14.1 Rartehome . American--cloth . 2.6 3.7 4.4 5.2 5.9 6.8 8.1 10.0 14.3 Schloesing Absorbent 4.8 9.0 12.5 15.7 18.5 20.8 22.8 24.3 25.8 ?uwa Australian merino--ekein 4.7 7.0 8.9 10.8 12.8 14.9 17.2 19.9 23.4 ffartahorne , Raw cbevennfis--skein 3.2 5.5 6.9 8.0 8.9 10.2 11.9 14.3 18.8 Scbloeaing -' Table cloth ' - 1.9 2.9 3.6 4.3 5.1 6.1 ` 7.0 8.4 10.2 Atkinson ' \ Dry spun--yarn 3;6 5.4 6.5 7.3 8.1 8.9 9.8 11.2 13.8 Sommer Average of several grades 3.1 5.2' 6.9 8.5 10.2 12.2 14.4 17.1 20.2 Storch - Manila and sisal--rope 2.7 4.7 6.0 7:2 8:5 9.9 11.6 13.6 15.7 Fuwa Rayons Viscose Nitrocellu lose Cupramonium Average skein Cellulose Acetate " Fibre' ; .. . 4.0 5.7 6.8 7.9 9.2 10.8 12.4 14.2 16.0 Robertson.. . 0.8 ;u 1.4 1.9 2.4 3.0 3.6 4.3 5.3 Robertson M. F. Newsprint . Wood pulp--24% ash 2.1 3.2 4.0 4.7 5.3 6.1 7.2 8.7 10.6. U. S. B.ofS. H. M. F. Writing Wood pulp--3% Mb 3.0 4.2 5.2 6.2 7.2 83 9.9 11.9 14.2 U. 8. B. of S. Paper White Bond . Rag--1% ash' 2.4 3.7 4.7 5.5 6.5 73 8.8 10.8 13.2 U. 8. B. of S. Com. Ledger 75% rag--1% ash 3.2 4.2 5.0 5.6 6.2 6.9 8.1 10.3 13.9 O. 8. B. of S. Kraft Wrapping Coniferous 3.2 4.6 5.7 6.6 7.6 8.9 10.5 12.6 14.9 U. 8. B. of 8. Leather. - . Sole oak--tanned 5.0 8.5 11.2 13.6 16.0 18.3 20.6 24.0 29.2 Phelps Catgut Racquet strings .4.6 7.2 8.6 10.2 12.0 14.3 17.3 19.8 21.7 Fuwa Glue Mlsc. Organic - Rubber Materials, Wood , Hide Solid tire Timber (average) 3.4 4.8 5.8 6.6 7.6 9.0 10.7 11.8 12.5 Fuwa ' o.ii 0.21 0.32 0.44 0.54 0.66 0.76 0.88 0.99 Fuwa 3.0 4.4 5.9 7.6 93 11.3 14l0 17.5 22.0 Forest P. Lab. Soap ,, White ... 1.9 3.8 5-7 7.6 10.0 12.9 16.1 19.8 23.8 Fuwa Tobacco Cigarette . . . -5.4 8.6 11.0 13.3 16.0 19.5 25.0 333 50.0 Ford . White Bread .. 0.5 1.7 3.1 .4.5 .6.2 8.5 11.1 14.5 19.0 Atkinson Crackers 2.1 ,2.8 ,3.3 3.9 5.0 6.5 83 10.9 14.9 Atkinson Food stuffs. Macaroni . Flour . . 5.1 7.4 8.8 10.2 11.7 13.7 16.2 19.0 22.1 Atkinson 2.6 4.1 S3. 6.5 8.0 9.9 1X4 15.4 19.1 Bailey Starch ' 2.2 3.8 5.2 6.4 7.4 8.3 9.2 10.6 12.7 Atkinson ' Gelatin 0.7 1.6 2.8 3.8 4.9 6.1 7.6 9.3 11.4 Atkinson ' Asbestos Fibre Finely divided 0.16 0.24 0:26 0.32 0.41 0.51 0.62 0.73 0.84 Fuwa Silica Gel Mtoe. Inorganic Domestic Coke Materials Activated Charcoal Steam activated v. -i 5.7 9.8 12.7 15.2 17.2 18.8 20.2 213 22.6 Fuwa 0.20 0.40 0.61 0.81 1.03 1.24 1.46 1.67 1.89 Selvig 7.1 14.3 22.8 2612 28.3 29.2 30.0 31.1- 3X7 Fuwa. . Sulphuric Arid ffjSO, - ; 33.0 41-0 47.5; 52^5 57.0 61.5 67.0 73.5 82.5 Mason . Chapter 40---Air Conditioning for Industrial Processes percentage of the total weight of material. Regain is more specific and refers only to hygroscopic moisture. It is expressed as a percentage of the bone-dry weight of material. For example, if a sample of cloth weighing 100.0 grains is dried to a constant weight of 93.0 grains, the loss in weight, or 7.0 grains, represents the weight of moisture originally contained. This expressed as a percentage of the total weight (100.0 grains) gives the moisture content or 7 per cent. The regain, which is expressed as a per- . 7.0 centage of the bone-dry weight, is or 7.5 per cent. The use of the term regain does not necessarily imply that the material as a whole has been completely dried.out and has re-absorbed moisture. In the case of certain textiles, for instance, complete drying during manu facturing is avoided as it might appreciably reduce the ability of the material to re-absorb moisture. In measuring moisture it is necessary to dry out a sample so that the loss in weight may be used as a basis for calculating the regain of the whole lot. , The moisture content of an hygroscopic material at any time depends upon the nature of the material and upon the temperature and especially the relative humidity of the air to which it has been exposed. Not only do different materials acquire different percentages of moisture after prolonged exposure to a given atmosphere, but the rate of absorption or drying out varies with the nature of the material, its thickness and density. Table 1 shows the regain or hygroscopic moisture content of several organic and inorganic materials when in equilibrium at a dry-bulb tem perature of 75 F and various relative humidities. The effect of relative humidity on regain of hygroscopic substances is clearly indicated. The effect of temperature is comparatively unimportant. In the case of cotton, for instance, an increase in temperature of 10 deg has the same effect on regain as a decrease in relative humidity, of one per cent. Changes in temperature do, however, affect the rate of absorption or drying. Sudden changes in temperature cause temporary fluctuations in regain even when the relative humidity remains stationary. TYPICAL INDUSTRIES REQUIRING AIR CONDITIONING A few of the industries in which air conditioning plays an important part and the major uses in these industries are as follows: Automobile. Drying of siccative coatings, manufacture of steel, manufacture of . artificial leather, drying of rubber, manufacture of tire fabrics; cementing of inner tubes, . conditioning of wooden spokes and other wooden parts, conditioning and manufacturing of all electrical windings in connection with the electrieal apparatus, storage battery plates and the rubber containers. Bakery. Flour storage, yeast and ingredient storage, mixers, fermentation rooms, make-up room, proof boxes, load cooling, wrapping (including paraffin paper), cake mixing and cake icing. Brewery. Fermentation and starting rooms. Chemical. Powders (including explosives and baking powder), drying of salts of all kinds, hygroscopic compounds and drugs, glues and gelatines. Clay Products. Bricks, pottery and ceramics. ` Confectionery. Chocolates, bon bons, hard candy, gum drops, marshmallows, caramels, chewing gum and starch and various sugars. ' 713 of andAmerican Society Heating Ventilating Engineers Guide, 1936 Drugs and Pharmaceuticals. Drugs and pharmaceuticals might also be included under chemicals, but definitely to be added to this group are capsules, hygroscopic colloidal crystals, serums and toxins. Electrical Goods. Toll cable manufacture, telephone exchanges, winding rooms, lamp manufacturer and filament departments. Films and Film Laboratories. Drying cabinets, printing rooms, perforating rooms, projection assembly rooms, moving picture studios, celluloid and color photography. Foods. Bread and cake, cereals, macaroni, meats (cold storage markets), yeast, enzymic products, fruits, including apples and bananas, both for preserving and ripening. Furs. Fur storage. Incubators. Human babies, chickens and similar hatching. Laboratories. All kinds. . Leather. Drying and processing of hides, skins and manufacture of bags, shoes and findings. Linoleum. Drying, printing, oil cloth, and linseed oil buildings. Matches. Storage of raw materials, machine drying and packing. Minerals. Gold beater rooms, gold and silver leaf manufacturing, metal enameling, and mottled ware, particularly all cutting on iron. . Paper and Paper Products. Moisture absorption in manufacture, cutting, folding, binding and furnishing bags, including gluing, parchment paper, cellophane containers, paste board containers, paste board bottles and egg containers. Pearls. Artificial pearls. Printing, Lithography and Rotogravure. Playing cards, process work, storage, offset work, binding, rollers and ink. Soap. Crystallizing under the cold process.. ' Textiles. Cotton: drying, spinning and weaving. Rayon: chemical house, spinning, drying, twisting, reeling,. winding, inspection and storage. Silk: storage, twisting and reeling, spinning, weaving, knitting, tin and lead weighing and regain rooms (hosiery and underwear). . Tobacco: Cigarettes: storage, mixing, blending, paper and machine manufacture. Cigars: storage, curing, cleaning, wrapping and packing. . v' It is apparent that the subject of air conditioning for industrial pro cesses is extensive and greatly involved, and that a detailed treatment is therefore beyond the scope of. this book. A few of the salient points of the general subject are covered in this chapter. , CLASSIFICATION OF PROBLEMS The problems of industrial air conditioning fall into four general classes: 1. Control of Regain. A 2. Control of Rate of Chemical Reactions. . 3. Control of Rate of Biochemical Reactions. 4. Control of Rate of Crystallization. .. . i . CONTROL OF REGAIN In the first class the textile plant offers a good example. The regain or moisture content affects the physical properties of textiles to a marked degree, changing the strength, pliability and elasticity. The fact that the regain of textiles will come into equilibrium .with the conditions of the surrounding air. and vary with its temperature, and relative humidity is the fundamental basis for the control of physical 714 I-!?.?1' Chapter 40--Air Conditioning for Industrial Processes qualities during manufacture. During the preparation process in a cotton mill, the fibers should be in a condition easily to be brought parallel to each other. . A relative humidity of 50 to 55 per cent gives the best result for these preliminary processes. As the cotton fiber comes to the spinning opera tion, more flexibility is needed and the relative humidity is increased in this department. For many years, 65 per cent relative humidity was considered the optimum. As pointed out in a paper presented-before the Cotton Manufacturers Association in 1926, a higher relative humidity is ' necessary to offset the extra work performed on the fiber as the spindle speed was increased. Today many cotton mills carry 70 per cent relative humidity in the spinning rooms. Winding, warping and weaving are all processes calling for great flexibility and a consequent need for higher humidity. Other textile fibers, due to their different natural characteristics, are processed under relative humidities and temperatures applicable to each. Rayons, on account of great loss of strength with the higher regains, should be processed in a relative humidity of 57 per cent. Acetate silk, another chemical fiber, with approximately 50 per cent of the regain of rayon, may be processed between 60 and 65 per cent relative humidity. All hygroscopic materials, when absorbing moisture, release sensible heat equivalent to the latent heat of the moisture taken up by the ma terial. This may account for a large percentage of the total load. CONTROL OF RATE OF CHEMICAL REACTION Typical examples of the second classification, the control of the rate of chemical reactions, occur in the manufacture of rayon. The pulp sheets are conditioned, cut to size, and passed through.a mercerizing process. It is essential that this' be under close control of both temperature and relative humidity. Temperature controls the rate of reaction directly, while the relative humidity maintains a constant rate of evaporation' from' the surface of the solution and gives a solution of known strength throughout the mercerizing period. . Another well known example of this class is the drying of varnish which is an oxydizing process dependent upon temperature. High relative humidities have a retarding action on the rate of oxydization at the surface and allow the gases to escape as the chemical oxydizers cure the varnish film from the bottom. This produces a surface free from bubbles and a film homogeneous throughout. Temperatures for drying varnish vary with the type. A relative humidity of 65 per cent is beneficial. In the field of biochemical control, industrial air conditioning has been applied to so many different and well known products that it is difficult to select an outstanding example. CONTROL OF RATE OF BIOCHEMICAL REACTIONS All problems involving fermentation are classed under this heading. As biochemistry is a subdivision of chemistry, subject to the same laws, the rate of reaction may be controlled by temperature. An example of this is the dough room of the modern bakery. Yeast develops best at a 715 American Society of Heating and Ventilating Engineers Guide, 1936 temperature of 80 F with a relative humidity of 65 per cent to hold the surface of the dough open, so that the C02 gases formed by the fermenta tion may pass out and produce a loaf of bread, when baked, of even, fine texture without large voids. Another example of a similar nature is found in the curing of macaroni. The flour and water mixture is fermented and dried. As it is necessary to have a definite amount of water present to carry on a fermentation process, the moisture must, be removed in a relatively short period to stop fermentation and prevent souring and in such a manner as to avoid setting up internal strains in the mixture. Best results are obtained with the correct cycles of both temperature and humidity. The curing of fruits, such as bananas and lemons, also come under this classification. Bananas are treated somewhat differently and to accom plish the required results, a cycle of temperatures and relative humidities is used. The starches in the pulp must be changed and the skin cured and colored. Then the fruit is cooled to maintain as slow a rate of metabolism as possible. Ideal conditions range between 55 to. 57 F, and in no case should the temperature go below 49 F, as the starches then become indigestible. 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 F to 59 F have been found to be best suited for this process. A high relative humidity, 88 to 90 per cent is necessary to hold shrinkage to a minimum and, at the same time, develop the rind so that it will be sufficiently tough to stand handling. Tobacco from the field to the finished cigar, cigarette, plug or pipe tobacco, offers another interesting example of what may be done by industrial air conditioning in the control of color, texture and flavor. In the processing of tobacco, the first three classifications of industrial air. conditioning are involved, and only through close atmospheric control can the best quality of the leaf be developed. CONTROL OF RATE OF CRYSTALLIZATION The rate of cooling of a saturated solution determines the size of the crystals formed. Both temperature and relative, humidity are of im portance, as the one controls the rate of cooling, while the other, through evaporation, changes the density of the1 solution. In-the coating kettles for pills, gum and nuts a heavy sugar solution is added to the tumbling mass. As the water evaporates, each separate piece is covered with crystals of sugar. A smooth, opaque coating is only accomplished by blowing into the kettle the proper amount of air at the right temperature and relative humidity. If the cooling and drying is too slow, the coating will be rough and semi-translucent, and the appearance unsightly; if too fast, the coating will chip thru 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. The foregoing is presented as typical of a few of the problems met with in industrial air conditioning. They are far from complete but, with the 716 Chapter 40--Air Conditioning for Industrial Processes help of a few of the natural laws, may act as a stimulus to the imagination . and assist in solving others. CONDITIONING AND DRYING In.general, the exposure of materials to desirable conditions for treat ment may be coincidental with the manufacture or processing of the materials, or they may be treated separately in special enclosures. This latter treatment may be classified as conditioning or drying. The purpose of conditioning or drying is usually 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. 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. Either conditioning or drying are frequently made continuous processes in which the material is conveyed through an elongated compartment by suitable means. ATMOSPHERIC CONDITIONS REQUIRED The most desirable relative humidity during processing depends upon the product and the nature of the process. As far as the behavior of the material itself and its desired final condition are concerned, each material and process represents a different problem. The best relative humidity may range up to 100 per cent. Similarly the most desirable temperature may range between wide limits for different materials and treatments. Extremes in either relative humidity or temperature require relatively expensive equipment for maintaining these conditions and controlling them automatically. Also, in departments where people are working, .their health, comfort, and productive efficiency must be considered. A ., compromise often is desirable. . It is generally considered that relative humidities below 40 per cent are on the dry side, conducive to low regains, a brittle condition of fibrous materials, prevalence of static electricity, and a tendency toward dryness of the skin and membranes of human beings. At the other end of the scale, humidities above 80 per cent are relatively damp, conducive to high regains, extreme softness, and pliability. Table 2 lists desirable temperatures and humidities for industrial pro cessing. In using this table, care must be taken in qualifying the process. In preparing many materials, conditions are not maintained constantly, but different temperatures and humidities are held for varying lengths of time. GENERAL REQUIREMENTS In general, air conditioning apparatus for industrial purposes must be capable of absorbing heat from various sources such as machinery power, electric lights, people, sunlight and chemical reaction; of warming or cooling to any desired degree, and of giving or permitting ample air supply at all times. Refrigeration may or may not be required, depending upon natural conditions, the required relative humidity and the maximum 717 American Society of Heating and Ventilating Engineers Guide, 1936 Table 2. Desirable Temperatures and Humidities for Industrial Processing Industbt Process Temperature Relative . Degrees Humiditt Fahrenheit PerCent Automobile......... Assembly line..................................................... Baking.................. Cake icing--.............................. -...................... Cake mixing------ ...---..............................-....... Dough fermentation room............................. Loaf cooling........................................................ Make-up room......... .....:----------T..................... ' Paraffin paper wrapping-...............--.......... Storage of flour..........................................-...... Storage of yeast................................................ Biological Products-....... Fermentation in vat room............-......:......... Brewing................ Storage of grains...........-................................. Ceramic.--............ Drying of auger machine brick................ . Drying of refractory shapes-....................... Molding room........ ............................................ Storage of clay................................................... Chemicai.......... ....... Confectionery.. General storage...............-................................ Chewing gum rolling--.....,....................... ..... Chewing gum wrapping....:........................-- Chocolate covering.......................................... Hard candy making........ ............................. -- Starch room............. ............... -....... .............. -- 65 70 75 80 70 75 to 80 75 to 80 80 80 to 90 70 to 80 28 to 40 below 32 38 to 42 44 to 50 60 180 to 200 110 to 150 80 60 GO to 80 75 70 62 to 65 70 to 80 65 . 75 to 85 60 to. 68 40 50 65 76 to 80 60 to 70 55 to 70 55 to 70 55 80 to 95 60 60 to 75 50 30 to 45 50 to 60 60 35 35 to 50 50 45 50 to 55 30 to 50 50 50 50 to 65 General manufacture.--............ ........... ;...... Distillery........... Storage of grains--........................................... Drug--. --- Storage of powders and tablets......... ......... Electrical...:;....... Insulation winding........ ............. -................... Manufacture of cotton covered wire......... Manufacture of electrical windings.--..... Storage of electrical goods.-->..................... Butter making.-................................................. Dairy chill room...................1....... -....... ..-- Preparation of cereals--.......... ...................-- Preparation of macaroni!--........................... Ripening of meats............................................ Storage of apples...... :....................................... Storage of citrus fruit.......... ----:....... Storage of eggs in shell.......................-.......... Storage'of meats.-- ...........- - ---.......... Storage of sugar.. ;.------ --..........----........ Drying of furs___ v.................................... ........... v-- Fuil_.........:............ Storage of furs...;.....:...'.;................................. 60 60 70 to 80 104 60 to 80 60 to 80 60 to 80 60 40 60 to 70 70 to 80 40 60 31 to 34 32 30 OtolO 80 110 28 to 40 45 30 to 45 30 to 35 5 60 to 70 .35 to 50 35 to 50 60 60 38 38 80 45 75 to 85 80 ' . 80 50 35 25 to 40 718 Chapter 40--Air Conditioning for Industrial Processes Table 2. Desirable Temperatures and Humidities for Industrial Processing (Continued) . Inddbtht ' Process Incubators.......... Chicken................................. I Temperature Degress Fahrenheit 99 to 102 Relative Humiditt Per Cent 55 to 75 Laboratory........ General analvtical and physical Storage of materials................... Leather.. _____ 60 to 70 60 to 7o' ' 60 to 70 35 to 50 90 Library.------------Linoleum.____ Book storage(seediscussioninthischapter) Printing................. 65 to 70 80 38 to 50 40 Manufacturing........................ Storage of matches.................1..... " . 72 to 74 60 50 , Munitions. ______ Fuse loading..................... 70 55 . Paint............................. Air drying lacquers. ................... Bakin? lacquers Air drying of oil paints......... ......... 70 to 90 180 to 300 60 to 90 25 to 50 25 to 50 Paper..:.......... ...... .Binding, cutting, drying, folding, gluing. 60 to 80 Storage of paper...... .................... 60 to 80 25 to 50 35 to 45 Photographic... 1 Printing....... " Development of film................ Drvin?...... .............. Printing........................... Cutt.ine............................. Binding__ ;........................... Folding............................. Press room (general)........................ Press room (lithographic).. _.......... .Storage of rollers...... ...................... 70 to 75 75 to 80 . 70 * 72 70 77 75 60 to 75 60 to 80 60 50 70 65 45 65 60 to 78 20 to 60 35 to 45 ; Rubber........... Soap.......... Manufacturing. ............. Dipping of surgical rubber articles. Standard laboratory tests._____ 90 75 to 80 . 80 to 84 25 to 30 42 to 48 110 70 Textile.:.. Cotton-- carding............... combine. ............ ' rovine...........1. spinning..,___ ;............... ` weaving.......... ........... Rayon-- spinning.... ................................. ..... twistine................ Silk-- dressing..................... spinning. ...................... ; throwing.................... ; . weaving ' Wool-- carding......................... spinning-- .................... ` ` - weaving..;...... ............ i....;..;. 75 to 80 75 to 80 : 75 to 80 60 to 80 68 to 75 70 70 75 to 80 . 75 to 80 . 75 to 80 75 to 80 75 to 80 75 to 80 . 75: to 80 , 50 60 to 65 50 to 60 60 to 70 70 to 80 . 85 65 ! 60 to 65 65 to 70 65 to 70 60 to 70 65 to 70 55 to 60 . 50 to 55 Tobacco.-....... ... Cigar and cigarette making.......................... . Stemmme or stripping......... 70 to 75 90 75 to 85 55 to 65 85 70 719 American Society of Heating and Ventilating Engineers Guide, 1936 permissible temperature. Washing, purifying and recirculating of the air may be desirable. Good distribution is essential to the control of air motion and for the prevention of undesirable conditions. Accurate, sensitive and reliable automatic control of humidity or temperature, or both, is vital in most cases. . Ordinarily, outside weather conditions and the ventilation required for workers are of secondary importance in relation to the total work to be done by the air conditioning system. In extreme cases of high concentra tion of industrial heat, from machinery and ovens the error of entirely omitting the heat gain through the building structure would not be serious. At the other extreme, where low temperatures must be produced with refrigeration and where comparatively little power is used for driving the machinery, the heat gain through the building structure will become . the major factor in determining the size of equipment and in this case the ventilation requirement assumes a normal degree of importance. Buildings which are to be air conditioned should therefore be designed with careful consideration of over-all cost and efficiency. Condensation resulting from high humidities must be prevented by suitable materials and construction, or else collected and drained to prevent loss of product or quick deterioration of the structure. Air leakage or filtration may add greatly to operating costs or make the maintenance of low humidities (relative or absolute) wholly impossible. Low temperatures require good insulation. ' -In.the general application of industrial air conditioning, the conditions . to be maintained are governed almost entirely by the requirements of the product. If any consideration is to be given to the comfort and, there fore, the efficiency of the occupants, it is. secondary. In a great many cases, the requirements of the product must necessarily govern, for the physical properties of the material are more important for maximum production than the efficiency of the worker. There are, however, many cases where the worker can and should be given equal consideration and better overall results may be obtained by a proper compromise. AIR CONDITIONING OF LIBRARIES1 Temperature has little effect on the preservation of books. A tempera ture over 100 F, combined with low relative humidity, may cause the book materials to become brittle, while a temperature much below freezing may cause permanent deterioration of the glue in the binding. The relative humidity should be maintained between 40 and 70 per cent, although these limits need not hold for short periods of time. If the relative humidity gets much below 40 per cent, first the glue and then the paper will tend to become brittle which will not cause any permanent damage unless the; book is used while in this condition, as a subsequent increase in humidity will bring the materials back to their normal condition. If the relative humidity gets above 80 per cent, the growth of mildew may be expected. . One of the principal agents of destruction and deterioration of paper *See U. S. Bureau of Standards Bulletin No. 128 entitled A Survey of Storage Conditions in Libraries, by Kimberly and Hicks. . ___.720 Chapter 40--Air Conditioning for Industrial Processes and books in libraries is sulphur dioxide gas in the air. If air containing sulphur dioxide is allowed to come in contact with cellulose, the principal constituent of paper, sulphuric acid is formed on the surface. This acid is not volatile at ordinary temperatures and therefore accumulates throughout the life of the paper. The destructive effect of the acid on the paper, is independent of the. relative humidity of the surrounding air. Low alkaline concentration spray water may be used in an air washer to neutralize the acid condition. Such an air washer must be. especially constructed to resist corrosion. GREENHOUSES Table' 3 lists customary dry-bulb temperature ranges for different types of plants and flowers raised in greenhouses. Table 3. Customary Temperatures for Different Types of Greenhouses* .Ttpe of House Temperature Range * Dbg F Type op House Temperature Range Deo F Carnation..................--1...................... - Conservatory (general collection).. Cool........ .......... ........ ............................ Cucumber..................... ......... ._............. Fern, Common..... ............... .............. Fern, Tropical......... ...... 1- Forcing............................. ..................... General purpose.................................. Lettuce................................................... Orchid, warm.-............. ...................... 55 to 65 65 to 70 50 to 60 65 to 70 60 to 65 65 to 75 60 to 70 60 to 70 55 to 65 65 to 75 Orchid, cool... Palm, warm... Palm. cool.*... Propagating... Propagating, Bottom heat.... Rose. .. _ Sweet pea....... Tomato........ Tropical......... Violet...... 50 to 60 65 to 75 55 to 65 55 to 60 70 to 75 65 to 70 50 to 60 65 to 70 65 to 75 45 to 55 tempeSureTM'1*" "ay ** ""^ered approximate night temperatures and Mgher values approximate day PROBLEMS m PRACTICE X Why is air conditioning required for some industrial processes? To control the physical properties of the materials being processed. Example. In the manufacture of chewing gum, it is rolled into slabs and scored; The scored slab must then be broken at the score marks to form the sticks. If the slab is too warm, breaking is impossible, if the slab is too cold or too dry, it becomes brittle and shatters, thereby producing much material to be reworked. 2 Why is it necessary to control the physical properties of the material being processed? ' To permit permanent adjustment of machinery. Example. In the manufacture of cigarettes, the amount of tobacco fed upon the paper tape is determined by pressure against springs. When the tobacco is over-moist and, therefore, over-soft, a great excess will go into the finished cigarette; when the tobacco is too dry and, therefore, harsh, too-little goes into the finished cigarette. 3 A condition of 75 F dry-bulb temperature and 55 per cent relative humidity is being maintained in a cigarette manufacturing department. What will be the regain and moisture content of the tobacco? . ' . :. : The regain, from Table 1 = 17.75 per cent. The moisture content = 17 75 X 100 = 15.1 per cen"t. . 100 + 17.75 721 American Society of Heating and Ventilating Engineers Guide, 1936 4 A 1-lb sample taken from a 100-lb batch of material is found to have a bone dry. -weight of 0.89 lb. This material is to be processed under atmospheric conditions which should produce a regain of 15 per cent. Compute the finished weight for each original 100-lb batch. -- Let W equal the number of pounds of moisture in a finished batch. gWg = regain = 15 per cent = ^15 W = 13.35 89 + 13.35 = 102.35 lb finished weight. 5 A bundle of sea island cotton is found to have a bone dry weight of 9.26 lb. What is the proper relative humidity at 75 F to produce a weight of 10 lb at equilibrium? - Desired conditioned weight = 10.00 lb Bone dry weight = 9-26 lb ' Weight of moisture required = 0.74 lb Regain = X 100 = 7.9 per cent. From Table 1, the proper relative humidity required is 60 per cent. 6 Compute the bone dry weight of 1000 lb of rnanila rope which has been stored for a considerable period of time in a conditioned room at 75 F dry-bulb temperature and 50 per cent relative humidity. Assuming that this material has come to equilibrium under the atmospheric conditions given. Table 1 shows a regain of 8.5 per cent. Let W equal the total weight of moisture in pounds. 1000 -- W = bone dry weight in pounds. W 8.5 1000 -~w = regain =8-5 P"cent = loo W = 78.3 lb moisture _ 1000 -- 78.3 = 921.7 lb bone dry weight. 7 0 An egg evaporating plant wishes to dry 2000 lb of egg whites (85 per cent water) to crystalline form each 24 hours. The maximum permissible air de livery temperature in the dryer is 140 F. What air volume will be requiredj assuming that outside air is at 95 F dry-bulb and 78 F wet-bulb and that air leaves the dryer 70 per cent saturated? . . Moisture to be removed = 2000 X 0.85 = 1700 lb. Using psychrometric chart and starting at the intersection of the vertical 95 F dry-bulb temperature line and the 45 per cent humidity line, move horizontally to the right to the .intersection with the 140 F vertical temperature line at 10 per cent relative humidity; then move along the constant heat (or wet-bulb line) to its intersection with the'70 per cent relative humidity curve and read 94 F dry-bulb, which will be the temperature of the air leaving the dryer. Moisture per cubic foot at 94 F and 70 per cent relative humidity = 11.8 grains Moisture per. cubic foot at 95 F and 78 F wet-bulb' 8.0 grains Moisture added per cubic foot of air handled 3.8 grains 1700 X 7000 24 X 60 X, 3.8 2170 cfm. No allowance is made for heat iost in the transmission to and from the dryer or for the heat required to raise the product from its entering temperature to that maintained in the dryer. This would necessitate a trial and error solution common tp all drying problems. 722 Chapter 41 DRYING Definition, Methods of Drying, Types of Dryer Construction, Mechanism of the Drying, Control of the Drying Operation, Dryer Design, Dryer Arrangement and Construction, Experimental Technique DEFINITION OF TERMS THE term drying, in its broader sense, refers to the removal of water or other volatile liquid from a gaseous liquid, or solid material. Except in the case of solids, the term is not ordinarily used unless the water or other liquid removed is present in a relatively small amount. In a more restricted sense, drying is the removal of water by vaporization from a non-volatile liquid or solid. Where the solid material to be dried contains large amounts of free water, the actual drying process is frequently preceded by the removal of part of the water by filtration, settling, pressing, centrifuging, or other mechanical means. Removal of as much water as possible by such methods is usually advisable, as the cost of these operations, per pound of water removed, is in general much less than by vaporization. METHODS OF DRYING Classification of Methods According to Heat Supply Drying methods may be classified basically in accordance with the means by which heat is supplied to the material to be dried. Thus, in . some cases, as in air current dryers, the heat of vaporization is transferred to the material from the atmosphere surrounding it. In natural air dryers, this heat is merely the sensible heat of the outdoor atmosphere; while in so-called artificial air dryers heat is added to the air by means of radiators or the addition of a heated gas such as superheated steam or products of combustion, the air being almost entirely displaced by such gases in some drying processes. Where products of combustion can be used, a particularly high overall efficiency of the dryer is possible. In-other types of dryers, known as contact dryers, heat is supplied by direct contact between the material and a heated surface such as a pan or shelf, such surfaces being heated by products of combustion, steam, hot water, heated oil, or electrical resistance. In both air dryers and contact dryers, additional heat may be supplied by direct radiation from hot surfaces which are in sight of the material. In the'jMw drying of raisins and other fruits, this radiant heat comes from the Sun, while in artificial dryers it is derived from heated surfaces such as steam coils. 723 American Society of Heating and Ventilating Engineers Guide, 1936 Radiant Heat Radiant heat can at best supply only a portion of the total heat of vaporization. About one-third to one-half of the heat given off by a radiating surface passes through the air to the object which is to be dried without materially raising the temperature of the intervening air. The remaining portion of the heat from the radiator warms the air by con vection and produces warm air currents which in turn transfer their heat to the material. A given amount of heat can be supplied to the material by means of heated air currents with only one-third to one-tenth as much radiating surface as would be required if this same quantity of heat were to be transferred by direct radiation. Direct radiation is, therefore, only an incidental source of heat in most dryers, except in the drying of certain kinds of material where the advantages of radiant heat will offset the higher first cost of the equipment. In vacuum dryers radiant heat is particularly useful in the drying of some bulky solids, owing to the difficulty of transferring heat to the material by means of rarified air currents at extremely low pressures. Continuous and Intermittent Operation Dryers may be operated continuously or intermittently. In the con tinuous type, the material is fed in at one end of the dryer and discharged at the other end when dry. The movement may be either a steady flow, or may consist of the periodic or progressive removal of a minor portion of the charge at one end of the dryer and the admission of a like portion at the other end, at more or less regular intervals. Dryers of the intermittent type, often called charge or batch dryers, are filled at the start with the material to be dried and are emptied again when the drying is completed, after which the process is repeated. The material in charge dryers is usually stationary but is sometimes shifted in position periodically or kept in continuous motion within the dryer for greater uniformity and speed of drying. With constant rates of flow of air and material, continuous dryers are usually simple to control and can be fitted advantageously into the train of manufacturing operations with minimum loss of time and requirements for storage and handling. Charge dryers, on the other hand, permit the use of complicated schedules of temperature and humidity which would be difficult to attain with continuous operation; and they have the important advantages of simplicity and low first cost, making them par ticularly; adapted to small installations and experimental work, ; Temperature and humidity conditions in a charge dryer should be sub stantially uniform throughout the dryer,- in order to produce uniform drying throughout the charge and prevent injury to the material. These conditions may remain uniform throughout the drying cycle or may be changed periodically as the drying progresses. In continuous or pro gressive dryers, the drying conditions usually vary from one end of the dryer to the other, either to suit the varying requirements of the different stages of drying or because of different rates of evaporation at different positions in the dryer. .. . With some materials, such as clay and other plastic material, the usual requirements are for the entering material to encounter the air at the 724 Chapter 41--Drying lowest temperature and highest humidity. As the material dries, it gradually moves forward to higher temperatures and lower humidities and encounters the highest temperature and lowest humidity just before leaving the dryer. This lends itself very nicely to a tunnel dryer with the air movement opposite to the travel of the material as the air cools and picks up moisture, producing the exact effect desired. Other material, like lumber, requires a high temperature and high humidity at the beginning, and lower temperature and humidity at the end. Such a condition requires very special handling of the air in a con tinuous dryer, and it is here that a batch dryer is of advantage. The material stands still and the entire dryer can be kept at any desired tem perature and humidity, which can be changed at will at any interval of time. In batch dryers it is almost always necessary to recirculate a con siderable proportion of the air to conserve the heat and to prevent the air from being too dry.. A continuous dryer, on the other hand, often does not require recirculation as the air has been in contact with the material for a longer time, and the increasing humidity and lower tem perature encounters material in various stages of drying. This question of recirculation is more fully dealt with later under Control of the Drying Operation. Low and High .Temperature Drying The division line between what is known as low temperature drying and high temperature drying is, roughly speaking the boiling point of water under ordinary atmospheric conditions. In high temperature drying, the temperatures range from 212 to 1000 F or more. Under these conditions, all of the water in the material will vaporize quickly and the humidity of the air becomes of minor importance. High temperature drying, is . usually faster and more economical of heat than low temperature drying, but often cannot be used because many materials, particularly foods and other organic substances, are injured or destroyed by temperatures above the boiling point. For such materials low temperature drying is required, the drying being produced by supplying enough heat to the material, and surrounding it with a sufficiently low humidity so as to produce a higher vapor pressure within the material at its surface than is present in the air surrounding it. As long as this difference in vapor pressure is maintained, the drying will proceed until completed. In drying with temperatures above the boiling point, the choice of means of heating the air becomes more difficult. Exhaust steam at low pressures becomes useless. High pressure steam may be used in coils, either in separate banks near the fans, or. as direct radiation. By this means, air may be heated to about 340 F. This does not mean, however, that the dryer will be as high as that. Above these temperatures, hot oil may be circulated in the coils. Occasionally electric heat is used, and in some cases superheated steam has been admitted to dryers requiring high temperatures. The most widely accepted method, however, is to . employ oil fired or gas fired air heaters which are now standard equipment in many industries, even when lower temperatures are required. This avoids putting drying loads (which often fluctuate widely) on the boiler plant. They also have the advantage of being independent for isolated locations. 725 American Society of Heating and Ventilating Engineers Guide, 1936 These heaters operate on two broad principles. The Direct Heaters mix the products of combustion with the air which is to be blown into the dryer. The amount of mixture is determined by the temperature desired in the mixture. The Indirect Heater passes the products of combustion through an interchanger which avoids mixing these gases with the air. With either type heater, multiple type burners are used in order to obtain automatic temperature control without sacrificing good burner per formance. The type of fuel used whether gas or oil depends on the locality and the important item of cost. The gas may be natural, manufactured as a by-product of coke, or derived from oil.. High heater efficiencies are secured with the proper selection of the type of heater and careful arrange ment of the heater in the drying circuit. .. Vacuum Drying ' It is sometimes advantageous to conduct the drying in a partial vacuum, in order to obtain rapid vaporization at comparatively low tem peratures. This, method is especially useful. for materials which are sensitive to heat, such as valuable food products which must be dried rapidly at low temperatures in order to preserve flavors and prevent harmful organic changes. A vacuum as high as 28 in. of mercury is sometimes used where a very low boiling point is desired, but the usual range is from 12 to 20 in. In vacuum drying, heat is supplied to the material either by contact with the heated walls or shelves of the container, which is the 'Usual method, or by direct radiation, either from the walls or shelves or from special radiators. Some materials containing only 2 to 3 per cent' moisture are first heated before being put in the vacuum chamber. When the vacuum is established* the heat already in the material vaporizes the moisture and becomes latent, thus drying and. cooling the material at the same time. - The air within the vacuum container is so rarified as to reduce mater ially its value as an agent for transferring heat from walls or radiators to the material. The volume of air which must be circulated in a vacuum chamber in order to transfer a given amount of heat is increased several times as compared with air at atmospheric pressures, and the cost of creating a circulation sufficient to transfer any large portion of the heat required for rapid evaporation, is apt to be prohibitive. The evaporated moisture is removed by means of condensers in the vacuum line. N. It should be clearly understood that a low temperature of product may not necessarily be secured in a vacuum dryer. If the material is very thin, is dried by radiant heat, and has a large amount of free water, then the temperature of evaporation for the constant rate period will cor respond closely with the temperature of water vapor equal to the vacuum maintained. After the critical moisture content is reached, the tem perature of the material is increased and approaches the temperature of the radiating or contact surface. With direct contact dryers, and especially with thick materials, the temperature is liable to be increased considerably over that corresponding to the vacuum. In these cases, much of the expected advantages of vacuum drying will be lost. (See later paragraphs on mechanism of drying, and dryer design.) . 726 Chapter 41--Drying Adiabatic and Constant Temperature Drying Air dryers are called adiabatic when the only source of heat for drying purposes is the heated air entering the dryer from the outside. When part or all of the heat required is applied by steam coils or other forms of radiation within the dryer itself, it is known as a constant temperature dryer. In adiabatic dryers, the temperature of the air decreases, as the drying proceeds, in direct proportion to the amount of heat consumed or made latent by evaporation. If this continued without new heated air being introduced, drying would slow down and finally stop. The constant temperature dryer does not depend on the air to carry the heat and only enough air need be handled to remove the water evapo rated. The great danger in the constant temperature dryer is that local zones in the dryer will vary widely in temperature, and hence, in hu midity, while in the adiabatic dryer temperatures and humidities should be qui.te uniform in a properly designed dryer. In the adiabatic dryer there is ample opportunity to use the zone system whereby the tem perature and. humidity may be different in various zones. This is often desirable in a continuous dryer where the required condition at the dif ferent stages is other than that which would result if the air were allowed to vary in temperature and humidity due to the evaporation which has taken place in the preceding zone. TYPES OF DRYER CONSTRUCTION Drum Dryers are used for drying thick liquids or pastes. A steam heated cylinder, with its lower side immersed in a bath of the material, is revolved slowly. The film of material that forms on the hot surface of the drum dries rapidly and the resultant solid is scraped off by a fixed knife edge. Cylinder or Can Dryers are designed for the continuous removal of moisture from material in the form of thin rolled sheets such as textiles, paper, and pulp products. Heat is transferred to the material by direct contact with a series of steam heated cylinders. In case the material shrinks on drying, as does paper, the drives must be arranged so that the speed of the drums is gradually less toward the dry end of the series. These dryers can be much improved as to speed and capacity by the application of jets of heated air to absorb the moisture as it leaves the material. This absorption of the vapor also prevents condensation on the ceiling and aids greatly in ventilating the dryer room. Pan or Agitator Dryers are used for sludges, powders, or material in lump form and consist of a cylindrical metal shell. The material to be dried is placed in the bottom of the shell and is constantly shifted in position by means of agitators, either the shell or the agitators or both being in motion. .Warm air, gas, or products of combustion, are passed over the material and additional heat is usually supplied from a steam heated jacket around the container, or by steam supplied to hollow stir ring arms. Continuous agitation of the charge serves not only to expose new surfaces to contact with the air, but also to reduce the average distance from the interior to the surface of the solid and so to speed up the drying where the rate of liquid diffusion to the surface is the controlling factor. . American Society of Heating and Ventilating Engineers Guide, 1936 Rotary Dryers are suited particularly to the continuous drying of granular, crystalline, or lumpy material which does not tend to ball or stick together. They consist of a revolving cylindrical shell into which the fresh material is fed at one end and from which the dry material is removed at the other end. Lifting plates usually extend from end to end of the inside of the cylinder, parallel to its axis, projecting radially toward the center. Warm air or products of combustion are blown through the shell, either parallel or counter current to the direction of movement of the material. The rotation of the cylinder continually elevates the material and drops or throws it through the current of hot gas or air, the inclination of the shell moving the charge forward at any desired speed. To furnish additional heat to the material by contact, the cylinder is often provided with a steam jacket or with steam coils inside the cylinder. In drying material which is not injured by high temperatures, the outside of the shell may be heated by products of combustion and these gases then led through the dryer in contact with the material. ' Spray Dryers - Spray Dryers are used for the drying of thick liquids, including any product in solution, suspension or emulsion, such as milk, rubber latex, chemicals and soap where the desired product is a powder or fine uniform particles. The liquid is usually first concentrated to from 35 to 50 per cent solid content and is then atomized in the form of a fine spray at the top of a lofty chamber, falling through a current of heated air or furnace gases, the dried powder accumulating at the bottom of the chamber. . The air can be heated to a considerably higher temperature than Would be used for the same material in a contact dryer because the critical tem perature in a spray dryer is the wet bulb temperature instead of the drybulb temperature. The drying is practically instantaneous. The spraying may be done by atomizing1 nozzles worked either by the .pressure of the liquid or by compressed air, or the liquid may be dropped in a fine stream onto a revolving disc rotating at high speed. That portion of the powder which is carried away with the air currents may be recovered in anyone of several types of dust collectors such as cyclones,, screens, dust bags or electric precipitators. The air or gas may be recirculated in part, after removing surplus moisture. Loft, Compartment, Cabinet or Room Dryers consist of room-like en closures or boxes in which the material to be dried is placed on trays, trucks, racks, or moving conveyors and is heated by warm air currents which also serve to carry away the evaporated moisture. Drying of this sort is sometimes called air-processing. The air is warmed, either by direct mixture with furnace gases, or by contact with surfaces heated by direct flame, flue gases, steam, hot water, or electricity. The source of heat may be direct--located within the dryer, usually in the form of wall coils, floor coils, or distributed coils--or indirect, the air being heated by radiators outside the dryer and circulated through the dryer by fans and distributing ducts. Baffles are often used to assure thg passage of the heated air directly over the surface of the material and to prevent shortcircuiting from inlet to outlet. Where the material is placed on trays, shelves or racks, it is advisable to use open-wire screen bottoms for small material or leave spaces between larger articles when possible, to allow 728 Chapter 41--Drying the air to travel not only over the material but also upward or downward through it. Tunnel Dryers consist of a comparatively long, narrow box-like en closure, through which the solid to be dried is moved either continuously or periodically at short intervals, being fed in at one end in a wet condition and removed from the other end in a dry condition. The material may be carried on some type of mechanical conveyor or on wheeled cars or trucks moving on a track. The drying is done by means of heated air which moves through the dryer from one end to the other, warming the material and removing the evaporated moisture. Some products dry best if the air and material are made to move in the same direction, but in most cases it is found best to have the air move in a direction opposite to the travel of the material, that is, counter-currently. Where wheeled cars are used for heavy, bulky products, the rails in the tunnel are often sloped in a ratio of 60 to 1, or 100 to 1, to obtain the benefit of gravity in moving the material. One end of the tunnel is usually hotter than the other, to suit the varying requirements of the different stages of drying. In the natural draft tunnel, heat is provided at the hotter end by steam coils or other means, and the. evaporated moisture is removed at the opposite end by means of ventilating chimneys. In the forced draft, or blower type of tunnel, the air is circulated through the tunnel by fans, being heated either by direct radiation within the tunnel, or indirect radiation in the fan duct, or a combination of both. Evaporated moisture may be removed either by ventilating chimneys or duct openings, or more rarely, by condensers in the duct system. Electric Induction Dryers ' Some new developments are occurring in the use of electricity for dryingor baking metal parts. Among these is a system whereby metal parts are passed through a high frequency field, thereby inducing currents in these parts. Heat is then generated within the parts themselves, baking from the inside out. The advantage of this system is a more efficient use of electricity, since oven temperatures are lower than work temperatures, keeping radiation and ventilation losses down to a minimum. This system can be applied only to production lines turning out uniform objects. The apparatus required, in addition to the conventional oven, is a high frequency motor generator set and a system of coils within the oven to obtain the proper electric field. ' MECHANISM OF THE DRYING Stages of Moisture Diffusion A thorough knowledge of the mechanism of the diffusion of moisture from the interior of a solid material to the surface and into the air is necessary to an understanding of the different types of commercial dryers, and is essential where the design of the dryer is to be based upon small scale laboratory tests. Assuming uniform velocity and distribution of air at a constant temperature and humidity, over the surface of the solid, the drying cycle will be divided ordinarily into two distinct stages. The first stage, known as the constant rate period, is found in the drying of any 729 American Society of Heating and Ventilating Engineers Guide, 1936 very wet solid as long as moisture is brought to the surface so rapidly that the surface remains thoroughly wet and evaporation can proceed at a constant rate, precisely as from a free water surface. The second stage, known as the falling rate period, is reached when the moisture in the material has been dried down to a point called the critical moisture content, below which the diffusion of moisture from the interior to the surface is no longer adequate to keep the surface thoroughly wetted. From this point on, the rate of drying will decrease until the operation is completed. Constant Rate Period During the constant rate period, the surface is kept saturated with water by diffusion from the interior and the operation is called saturated surface drying. The rate of drying is limited by the rate of diffusion of water vapor, through the surface air film surrounding the solid, out into the main body of the air. When the heat necessary for vaporization is supplied only by thermal conduction through the surface air film, the temperature of the solid is the wet-bulb temperature of the air. Heat gained by radiation or conduction from adjoining dry surfaces raises the temperature of the surface above the wet-bulb temperature. The. vapor pressure of the water at the surface, therefore, increases and consequently the driving force causing diffusion through the surface air film becomes greater, causing a corresponding increase in the drying rate. By placing the wet material in sight of hot surfaces during this constant rate period, the rate of drying may be increased several fold without overheating the material itself. Similarly, material placed on hot shelves, as well as material dried in shallow pans or on heated cylinders, will dry faster because of the heat received by conduction from the surfaces with which it is in contact. A controlling factor during this stage is the velocity of the air, affecting as it does the thickness of the surface air film through which the water vapor must diffuse. The higher the velocity, the faster will the drying proceed, the rate of dfying varying approximately as the 0.6 power of the air velocity. Falling Rate Period ' After the critical moisture content of the material has been reached, two distinctly different forms of diffusion and evaporation are en countered. In both cases, the drying rate falls off rapidly with reduction of the moisture content. In the first type, known as unsaturated surface drying, the rate of evaporation per unit surface area is substantially con stant and nearly independent of the thickness of th^sheet or layer of the material. However, where the solid gains its heat only from the air around it and obtains none by radiation or conduction from adjacent surfaces, the transfer of heat from the air to the solid is, under constant drying conditions, found to be independent of the moisture content and of any variation in the drying rate due thereto. Furthermore, the drying rate is increased by greater air velocity and by lessened humidity of the drying air. These facts are explained by assuming that evaporation takes place on the surface of the solid, but that the concentration of moisture there is insufficient to saturate the whole surface, so that the surface behaves as though only a part of it were wet. 730 Chapter 41--Drying In the second type of diffusion, known as sub-surface drying, the rate of evaporation per unit surface area of the sheet of material is inversely proportional to the thickness and is uninfluenced either by the velocity or the humidity of the surrounding air. The heat transfer from the air to the stock falls off rapidly as the moisture content and the drying rate decrease. This indicates that evaporation is taking place, not at the surface of the solid, but beneath the surface, so that water as vapor must diffuse not only through the gas film around the solid, but also through that layer of the solid itself between the zone of evaporation and the surface. Con sequently, this type of evaporation is known as sub-surface drying, the Fig. 1. Rate of Drying of Whiting Slab limiting factor in the rate of drying being the speied of diffusion of the liquid water from the interior of the solid to the zone of evaporation. The Drying Cycle . In the drying of a typical wet solid under constant conditions, saturated surface evaporation usually starts at a constant rate. This will continue until the critical moisture content of the stock is reached, after which there will follow a period of unsaturated surface drying, at a falling rate. This is finally superseded by sub-surface drying which continues at a decreasing rate until the operation is completed. Thfe drying of a slab of whiting gives a typical illustration of this cycle, as shown in Fig. 1. Omissions in the Cycle Many solids, such as lumber, are so dry at the beginning of the drying operation that the constant rate period of free surface evaporation does not occur. Frequently the surface of the material is dry enough so that no surface drying can take place, in which case only the final stage of sub 731 American Society of Heating and Ventilating Engineers Guide, 1936 surface drying is involved. In other instances, the critical moisture con tent of a wet solid is sufficiently low that sub-surface drying starts almost immediately after the conclusion of the constant rate period. Thus the intermediate stage of unsaturated surface drying does not occur and the drying is of the sub-surface type during practically the whole of the falling rate period. With other kinds of material, particularly thin sheets, such as newsprint paper, sub-surface drying may occur at such a low moisture content that it is not encountered in commercial work, the falling rate period being confined solely in practice, to unsaturated surface drying. Capillary and Hygroscopic Moisture Most solid materials to be dried are of a powdery, granular, cellular, or fibrous nature and contain water in two characteristic forms which have a direct relation to the rate and character of the drying operation. The first form is known as free or capillary moisture and comprises the water which is contained in the capillary spaces between the particles or fibres of the material. The second form is called adsorbed or hygroscopic moisture and is intimately associated with the physical nature of the material, having a direct effect upon such physical properties as size, strength, electrical conduction, heat conduction, etc. Removal of the capillary water has little or no effect upon the material except to reduce its weight, while removal of the hygroscopic water causes definite changes in physical properties and characteristics. Fiber Saturation Point The total amount of adsorbed or hygroscopic moisture that a given amount of material can contain is definitely limited. This limit is known as the fiber saturation point1 and corresponds roughly to the critical moisture content. Beyond this point, any additional moisture must be in free or capillary form and the amount of such free water that the material can hold will depend upon the relative volume of capillary spaces that may be present. The fiber saturation point is of particular impor tance in the drying of thick, bulky materials having a more or less colloidal structure such as lumber and clay products, in which the removal of hygroscopic moisture is accompanied by shrinkage, stiffening, hardening, loss of plasticity, and other physical changes. Successful drying requires that these changes be controlled within safe limits in order to .avoid injury to the material. " Removal of Free Water " In most commercial products which require a drying operation, the free water contained will flow readily from the interior to the surface by capillary action, as in a wick. Textiles, pajper, fiber board, clay products, and the sapwood of most species of lumber represent material'Of this type, as well as finely divided materials which come in granular or powder form. In such substances the free water is removed usually without difficulty in the successive stages of saturated surface drying and un saturated surface drying, followed by the removal of the hygroscopic moisture in the form of sub-surface drying. U. S. Forest Service Bui. 70. p. 82. Effect of Moisture on Strength. Tiemann, 1907. 732 Chapter 41--Drying In certain other materials of thick and more or less rigid form, notably, the heartwood of some kind of lumber, the free water contained in the capillary spaces appears to be, in a sense, bottled up and cannot be made to flow from the interior to the surface in appreciable amounts. To remove the free water from such substances necessitates sub-surface vaporization within the material at the boundary of the free water zone, followed by diffusion of the vapor through the surrounding zones either as vapor or as adsorbed hygroscopic moisture. In either case, the zone surrounding the free water must be dried, below its fiber saturation point in order to lower the vapor pressure to a point below saturation and thus permit this diffusion to take place. This means that shrinkage and other physical changes, such as stiffening or hardening, must occur in this outer zone before the interior portions have lost their free water and are ready for such changes. Consequently severe and harmful tensile and compressive stresses are apt to be set up in the drying of this type of material, due to unequal and non-synchronous shrinkage in the different zones, resulting in such injuries as surface cracking, honey-combing, warping, and case hardening, or the setting of the surface portion in a stiffened expanded condition. . In obtaining maximum speed of drying of materials in which there is no capillary flow of free water to the surface, dependence is placed in most cases upon the effect produced by heated air or other gas surrounding the material. In such cases the speed of drying can be increased in only two ways, first, by lowering the moisture content at the surface through the use of a.lower humidity, or second, by increasing the temperature. The risk of harmful shrinkage limits the first, and the risk of exceeding the critical temperature of the material limits the second. ' In many cases, however, increased speed of drying can be secured by increasing the tem perature of the air, and at the same time, increasing its humidity. In this way the amount of heat passing into the material is increased, while the increased humidity prevents the surface drying too fast and racp hardening. An extreme example of this method is turning steam- into a dryer in which green lumber is being dried. The use of too high a temperature in removing the free water from fibrous or cellular materials of this kind, increases the plasticity of the structure and, at the same time, is apt to create a liquid tension within the cells themselves. This force, which may amount to many atmospheres under certain conditions, tends to draw the walls of the cells together, thus producing a collapse of these cells. This phenomenon is the cause of much injury in the drying of certain kinds of lumber and is probably present, to a greater or less extent, in the drying of all refractory material of a cellular nature through which the free water cannot flow by capil larity. - Another result of trying to force the drying of these refractory materials at too fast a rate, is the increasing resistance to the passage of heat from the surface to the interior and the passage of vapor outward, as the dryness of the surface increases. With many materials of this type, if the surface is allowed to dry below a certain point, it becomes increasingly difficult, not only for additional heat to penetrate to the interior, but also for vapor to work its way outward through the dry outer zones to the 733 American Society of Heating and Ventilating Engineers Guide, 1936 surface. Under these conditions, artificially increasing the humidity of the surrounding air is often a valuable help. Internal Moisture Gradient . In drying by surface evaporation, an internal concentration gradient is set up between the moisture content at the center of the material and the moisture content close to the surface. The steepness of this gradient is dependent upon the rate of evaporation at the surface and the rate of transfusion of moisture from the center outward. In general, the steeper the gradient, the faster the drying. Since raising the temperature in creases the rate of transfuion, the rate of drying is thereby increased without increasing the steepness of the gradient. For this reason the maximum temperatures which can be used without injury to the material will usually be found to produce the maximum rate of speed consistent with safety. ', In keeping the moisture gradient within safe limits, during those stages of drying when surface shrinkage is taking place, the drying should be retarded by preventing the surface from drying below a certain critical moisture content which must be determined .experimentally for different materials. This control of surface drying is accomplished by regulation of the relative humidity of the air in the dryer in conjunction with the regulation of the temperature. The most inexpensive means of securing the desired humidity is to recirculate a sufficient portion of the air. This not only utilizes the moisture which has previously been evaporated from the goods, but also conserves the heat contained in the air. . Equilibrium Moisture Content With every material having hygroscopic properties, a point of equi librium is reached between the vapor pressure of the moisture in the air and the vapor pressure of the moisture in the surface of the material. Every combination of temperature and' humidity produces a corressponding equilibrium moisture content in the material. It is, therefore, possible to so regulate the conditions in the dryer at any stage of the operation that moisture in the material cannot drop below a certain equilibrium point, as may be desired for best results. In the drying of most hygroscopic materials, the drying is continued until a somewhat lower moisture content is reached than equilibrium under conditions in use, to allow- for enough regain to balance the moisture re maining -in the interior and surface to a uniform condition. It is usually undesirable to carry the drying much beyond the equilibrium point of the material in use, as over drying is liable to.produce undesirable physical changes in the material, and such over drying also unnecessarily prolongs the time and increases the cost of the operation. . - i. CONTROL OF THE DRYING OPERATION ' Circulation . It will have been seen that in any successful dryer heat has to be applied and the water evaporated has to be removed. A circulation of air or gas inside the dryer is essential for three reasons. First, all the heat, except such as may be supplied by conduction and radiation, must be 734 Chapter 41--Drying supplied by the air circulation. Secondly, the air must, carry away the water vapor resulting from the drying. Third, duty of the air circulation is to have sufficient velocity to sweep away the film, or layer of nearly saturated air that is apt to remain in close contact with the evaporating surface, and whose high vapor pressure retards further evaporation. During the saturated and unsaturated surface drying stages, the drying rate will vary directly with the velocity of circulation over the material. When the stage of sub-surface drying is reached the velocity of circu lation at the surface becomes of less importance, except that it must maintain uniform temperatures about the material, in order to produce uniform drying. Circulation is expressed either by the rate of air flow over the material per minute, or by the number of air changes in the dryer per minute or per hour. The former is the more logical method. The air change expression is really a relic of the days when all fresh air was used, while an efficient dryer often uses only a portion of fresh air and the bulk of the air is recirculated. As will have been seen, the heat required for evaporation is extracted from the air. If a small quantity of air is circulated through the dryer, it will be evident that a great drop in the temperature of the air occurs. This causes a great variation of temperature in contact with the material. In addition to this drop in temperature, a small quantity of air means the absorption of a large amount of vapor. The combination of these two factors will result in widely varying drying effects in different parts of the dryer. The larger the amount of air circulated, the less will be the drop in temperature, the less will be the amount of vapor absorbed per cubic foot of air, and hence, the closer will be the drying effects of the air in various parts of the dryer. If this large quantity of air, however, is all fresh air and the entire amount exhausted, the air thrown away will be far from having reached'the proper saturation and a great waste of heat will occur. It may be sufficient to exhaust only a very small percentage of the amount of air that would be best from a circulating standpoint. Therefore, to meet both conditions, it is usually best to determine the volume required for circulation, then to only exhaust the portion that is sufficient to carry away the moisture and to recirculate the balance, introducing fresh air. only in an amount equal to the amount exhausted. The higher the temperature of the dryer and the higher the humidities carried, the greater becomes the amount of air recirculated. In some dryers the recirculation is obtained by the use of propeller type fans inside the dryer for recirculating over and over while the proper amount of fresh air is discharged into the dryer by a separate fan located outside. In other dryers, the fans for circulating the air are located out side the dryer and so arranged that a large portion of the air is recirculated and the rest introduced as fresh air into the same fan. In other dryers, a . rapid circulation is passed through one section of the dryer; the entire amount is withdrawn, treated as to temperature and humidity and then introduced into the next section of the dryer. This results in a very slight drop in the temperature of the air in any part of each section, and by adding heat at each stage, the temperature and humidity can be con trolled as desired throughout the dryer. Next to circulating the proper amount of air, the most important con- 735 / American Society of Heating and Ventilating Engineers Guide, 1936 sideration is the. method of introducing the air to the dryer. This is often called the distribution system. If there are dead areas, the air in that section will cool down rapidly, saturation will be reached and drying will be much slower in that section. If drying is to be uniform, then the circulation in every section of the dryer must be uniform. In addition, care must be taken not to have the air travel too far, causing a tempera ture drop too great and causing just as unequal drying conditions as if there were not enough circulation. The velocities must also be uniform over the goods at all parts or the drying will again become uneven. Many of the older types of dryers were, and still are, of the type known as gravity or natural draft dryers. In these dryers, the natural laws of gravity are utilized to create a circulation. By regulating dampers and using chimneys or stacks, the moisture laden air is permitted to escape and an equal amount of fresh air admitted. The system is simple, and in some cases, may be adequate. The circulation cannot be increased beyond the amount of fresh air used, and hence, the circulation is inadequate to > carry the proper heat uniformly through the dryer. This usually means that the drying is slow and often varies as the weather fluctuates. In a gravity dryer the circulation is usually slow, and such dryers are practi cally limited to materials which require baking or similar heat treatment rather than removal of much moisture. Even in a baking process, however, a rapid circulation results in much more even application of the heat so that most modern dryers have mechanical. circulation by fans. Many materials, such as gelatines, photographic films, etc., require drying at temperatures lower than the outside temperature. In such cases, the air must be cooled and dehumidified by refrigeration. It is then most economical not to use any fresh air in summer, but to recirculate all the air and remove the excess moisture by means of cold sprays of water or cooling coils. In high temperature dryers, on the other hand, the required temperature may be higher than steam temperatures and these may be secured either by entirely heating the air by oil or gas fired heaters, or such heaters may be utilized as a booster to the steam heated air. As such dryers need only a very small amount of fresh air, it may be best to recirculate a large volume and introduce only a very small quantity of fresh air heated to a high temperature by oil or gas heaters. These make possible temperatures up to 1000 F. ' It is obvious that the air circulating through a dryhr cannot be at the saturation point or drying would stop. The amount of saturation 'that can be carried in a dryer varies with the design of the dryer, rarely being ' over 50 per cent in a batch type dryer while in a tunnel dryer it may be 75 per cent or even higher. . Heat and Humidity Control ' Regardless of whether the source of heat is steam or oil or gas fired heaters, there should be absolute control over the temperature and humidity. There is very little excuse today for hand operated valve control. If results do not have to be very accurate, a periodic setting of a thermostat and hand controlled dampers may be sufficient, but, in any case, there should be a recording instrument on every modern dryer. Only in this way can there be a check of the vigilance of the operator. The controls may be made more elaborate controlling automatically the 736 Chapter 41--Drying heat source, the humidity source, the amount of air recirculated and the amount of air exhausted. Although these are usually set to produce the desired temperature and humidity, in some cases controls have been developed which mechanically change their settings in accordance with a predetermined schedule. In some cases samples of the material are suspended on sensitized scales in the dryer opposite peep holes and the dryer is operated until the samples have reached the proper weight. Operating the Dryer No matter how well the dryer may be designed, a considerable part of the success of a drying operation depends upon the operator. He must watch the material and study the results in a constant effort toward improvement. Good dryer operation includes regular sampling and testing of material, watching the conditions within the dryer, and keeping systematic and complete records of all essential data, such as the move ment of material, the length of the drying period, the temperatures and humidities at critical points in the dryer, and the extent to which the equipment is kept fully occupied. Standard schedules of drying time and drying conditions for material of different kinds are also useful in esti mating production and regulating the operation of the dryer. Moisture Content Calculations Moisture content is usually-expressed as a percentage of the original combined weight of the material and its contained water. Thus, if the moisture content were 20 per cent, the dry material would weigh 80 per cent of the total weight. In drying some types of material, notably lumber, it is customary to use the bone dry or water free weight of the material as the divisor, the weight of the water being calculated as a percentage of this dry weight. Regain, or absorption of hygroscopic moisture after drying, is almost always expressed by the latter method, as a percentage of the water free weight of the material. The usual procedure, in determining the moisture content of a repre sentative sample of the material, is to weigh this sample before it has had a chance to lose weight by evaporation, then dry it to a water free basis in an oven heated to a temperature Slightly above the boiling point (about 215 F) until it has reached constant weight, then take a second weight record, and subtract the second weight from the first to determine the weight of the water. This-figure can then be multiplied by 100 and divided by either the first weight or the second weight to obtain the percentage based on the original or final weight of the sample. Ovens used for this purpose are usually heated by steam or electricity and thermostatically controlled to prevent overheating. Time of Drying In Table 1, the average temperature range and drying time for a number of representative materials is given. The figures do not represent the maximum speeds attainable, nor necessarily the optimum temperature conditions, but are fairly typical of general commercial practice. In materials in which no capillary movement of free water can take place, the speed is limited by the rate of transfusion through the material, which is again determined by the critical temperatures and maximum gradients 737 American Society of Heating and .Ventilating Engineers Guide, 1936 Table 1. Drying Time and Conditions for Representative Materials Kind and Thickness or Material Temperature . Deo F Dbtino Time Bedding____ Cereals.......... Cocoanut..... Coffee............ Cores, Oil Sand, for molding.:...................J4 in.--1 in. thick Black sand with Goulac Binder about} o |JJ` 6/10 of time for oil sand cores................Kg jn' Feathers...... .........................................:....................... :................. . Films, Photographic............................ ...... ............... ................. Fruits and Vegetables................................................................. Furs................................................................................................... Glue...... ...................................................... ........................ ............. Glue Size on Furniture...... ....................:................................... Gut............................... ..... ............................................................... Gypsum Wall Board--: in. t.h, -ic,k------------------/{SFtianirsthWet Gypsum Blocks-....... .......... ....... Hair Goods.--................................ Hats, Felt-.................................... Hops........................ ........................ Hides, Thin. Leather--.............. Ink, Printing................................. Knitted Fabrics--....................... Leather, Thick Sole.................... Lumber, Green .Hardwood--.... Lumber, Green Softwood--..... Macaroni.................. ...................... Matches............................ .............. Milk and other Liquid Foods (Spray Dried)_________ _____ Molds, Green Sand, C. I. Flasks (one surface only exposed) 8 in. thick ' 13 in. thick__ Nuts................. .... ..... ! Paper, Machine Dried- Paper, Air Dried Rubber..,:......................... Sand, loose, 1 in., deep.--- Shade Cloth......................... Soap........ ....................... ....... Starch...............................-- Stock Feed, Mixed....!...... Sugar- Tannin and other chemical (Spray Dried)-....... ;-- Terra Cotta (air-drying in conditioning room)........ Wall Board, pasted ply board__ ................................... Wall Board, fiber-insulating, Roller Type Dryer- Wall Board, fiber insulating, Truck Type Dryer-- 150-190 110-150 145-155 160-180 300 480 480 700 150-180 90 140 110 70-90 130 150 350 275 350-190 150^190 140-180 120-180 90 70-300 '140-180 90 100-180 160-220 90-110 140-180 250-300 600 700 75-140 180 90-200 80-90 300 240 125 180-200 180-220 150-200 250-300 150-220 300 300-385 300-385 4--6 Hours 24 Hours 30 Minutes 2)4 Hours 4)4 Hours 10 . Hours 2-6 Hours 2-4 Hours 4 Hours 60 Minutes 8-16 Hours 1 Hour 2-4 Hours 4r-6 Hours 3-180 Days 2-14 Days Instantaneous 6 Hours 13 Hours 24 Hours 6-12 Hours 10-15 Minutes 1-2 Hours 12 Hours . 1-4 . HourS. 20-30 Minutes 20-30. Minutes Instantaneous 12-96 Hours 15-20 Minutes 2)4-3 Hours 24--48 Hours 738 Chapter 41--Drying which can be used without injuring the material. In this case, theoretical analysis, according to Lewis, shows that in the early stages the time of drying is proportional to the square of the thickness and to the square of the total moisture lost, and the time moisture curve is a parabola. In the later stages, after all free water has been evaporated, the curve becomes logarithmic. The form of this drying curve will, in general, resemble that shown in Fig. 2. On the other hand, in drying material in which free water can flow by capillary action at a sufficient rate to keep pace with surface evaporation, the time, is proportional, to the first power of the thickness and the rate will be governed by the drying conditions of the air and the area of surface exposed. DRYER DESIGN Methods of Calculations - , . A psychrometric chart applying to atmospheric pressure and plotted in units convenient for use in dryer calculations, is given in Fig. 3. The amount of moisture in the air, H is given in pounds of water per pound of dry air. With this choice of units, changes in H represent directly the moisture picked up by the air from the material being dried. The inclined Fig. 2. Typical Time-Moisture Curve for Materials in which no Capillary Flow of Free Moisture Occurs straight lines are adiabatic cooling lines for air in contact with water at its weGbulb temperature, and also represent the cooling of air in the adiabatic drying of any stock, the sensible heat of which is negligible in comparison with the heat of vaporization of the water in it. The following nomenclature and explanation of terms will be used in the discussion of drying calculations: H = humidity of air, pounds of water vapor per pound of dry air. G -- pounds of dry air supplied to the dryer per unit of time. ' 5 = 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. . Q = total heat supplied to the dryer. t = air temperature. 1' = stock temperature. t" = average stock temperature over short time interval, in a batch dryer. tw = wet-bulb temperature, s' = specific heat of the stock. 739 HUMID HEAT (Btu PER DEG FAHR PER LB BONE DRY AIR), n ? 4 ' 0.26 0.28 0 .3 a ' 0-32 . / American Society of Heating and Ventilating Engineers Guide, 1936 .740 Chapter 41--Drying B = total radiation and conduction losses per unit time. w = pounds of water per pound of dry stock. - r = heat of evaporation of water. : s = humid heat of air, i.e., heat necessary to raise 1 lb of dry air + H\b of steam 1 deg. Subscript (1) designates conditions at the point where the material in question (air or stock) enters and (2) where it leaves the dryer. . Air dryers may be divided into two classes, those in which all moisture evaporated from the stock leaves the dryer as vapor in the effluent air, and those in which part or all of the moisture is condensed from the air in the drying equipment itself. In any continuously operating dryer of the first type the relation between moisture content of the stock and quantity of air required for the drying operation is given by the equation: G (Ht -- Hi) = 5(u)i -- aij) ' (1) In discontinuous dryers, e.g., compartment dryers, the drying operation is given by the equation: G (Hi - Hi) = S' ^ (la) In the continuous dryer, the heat consumption per unit time is: -Q- = Gsi(ti -- A) + G(ri + ti -- I's) (Hi -- H\) -f- S(t'i -- t'i) (s' -f- 101) -f- B (2) Equation (2) assumes continuity of operation. For charge or batch operations, the total time of the drying cycle may be broken up into a number of periods, sufficiently short so that over each period average values of t, t' and H may be employed provided the third term of the right hand member of the equation is modified to read: S' (<"1 - f.) (s' -Wi) and in the second term f'j be replaced by fi + t'\ 2 Theoretically these periods should be very short and the equation integrated. Practically the error introduced by using ai small number of long periods and employing average values of the variables over each, rarely introduces serious error. The evaluation of equation (la) may be approximated in a similar manner. . The first term of the right hand member of equation (2) 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 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 (G), and a corresponding minimum loss,' as sensible heat, in the exit air. Similarly, continuous operation is superior to intermittent operation. 741 American Society of Heating and Ventilating Engineers Guide, 1936 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 decreases, provided the increase in moisture carrying capacity of the air, due to high temperature, is actually utilized. To secure maximum thermal efficiency in drying, a high drying temperature and high satura tion of the outlet air is imperative. The Ventilation Phase The technique of attack of the ventilation phase of a drying problem is best made clear by an illustration. Assume that a material containing 40 per cent moisture is to be dried until this quantity of moisture is reduced to 5 per cent by weight. The material will stand an air tempera ture of 150 F and it is possible to provide sufficiently good contact between the material and the drying air so that the effluent air can be L brought up to 50 per cent humidity at 150 F. The dryer is to use room air, the temperature and humidity of which may be assumed to average 70 F and 50 per cent. A counter-current dryer will be employed and the air in this dryer will be kept at a substantially constant temperature of 150 F by heaters thermostatically controlled. The stock enters at 70 F, rises quickly to the wet-bulb temperature of the air, with which it is in contact, and is found experimentally to maintain wet-bulb temperature until the moisture content has fallen to 20 per cent. From this point its temperature rises progressively as it dries. In this range the difference in temperature between stock and air, divided by the wet-bulb depression, " may be assumed proportional to the moisture content. The moisture content of the entering stock, in the units here employed, is: 40 per cent water 60 per cent dry stock 0.6667: wt 5 per cent water = 0.0527 95 per cent dry stock a,, _ = A w = 0.614 lb water evaporated per pound of dry stock. Since the air leaving the dryer is 50 per cent saturated at 150 F from Fig. 3, Hi -- 0.105. Similarly, Hi = 0.008, corresponding to 50 per cent humidity at 70 F. Consequently H, -- Hi = is H = 0.097 lb water evaporated per pound dry air. Inspection of equation (1) shows that (H) is linear in w. Hence, one can construct on Fig. 4, the line marked (H) being drawn connecting the initial and final points just computed. Since the air leaving the dryer has a temperature of 150 F and a humidity of 0.105, Fig. 3 shows that its wkt-bulb temperature is 129 F. This is plotted at the.-right hand side of Fig. 4. Since the stock maintains a wet-bulb temperature down to 20 per cent moisture, where w = 0.25, the corresponding humidity can be computed by the use of equation (1) or by reading directly from the diagram, the value being 0.0392; Fig. 3 shows that the corresponding wet-bulb temperature is 105 F. - Any intermediate point on the wet-bulb temperature curve can be calculated similarly. The points for w = 0.5 are shown in Fig. 4. Below the point, w = 0.25, the temperature of the stock begins to rise appreciably above the wet-bulb temperature. Its temperature at any given point in this range, for example at w = 0.15, may be computed as follows: At this point, H = 0.0234 (from equation (1)) and from Fig. 3, V = 95 F. Hence the wet-bulb depression, t -- t* = 150 -- 95 = 55 F. 742 Chapter 41--Drying The assumption made regarding the relation between stock temperature and moisture content in this range may be formulated: . A t' w t - tm ~ 0.25 At the point w = 0.15, At' = 33 F, tx = 117 F. The temperature of the stock leaving the dryer, similarly computed, is 136 F. Fig. 4 thus computed gives in graphical form the information as to the temperature humidity relationships in the dryer. The air requirements can be computed by equation (1). Thus, per 100 lb of dry stock, it is necessary to supply 633 lb of dry air. Furthermore, since from Fig. 3 it is seen that the volume of 50 per cent saturated air at 70 F, is 13.55.eu ft per lb, 8580 cu ft of room air must be supplied per 100 lb dry stock. Fig. 4. W-P0UNDS OF WATER PER POUND DRY STOCK Chart Showing Temperature-Humidity Relationship in a Dryer Similarly, since the volume of 50 per cent saturated air at 150 F is. 18.0 cu ft per pound, the volume of hot wet air discharged from the dryer is 11,400 cu ft per 100.1b of dry stock. Finally, the heat necessary to supply to the dryer; as a whole, or to any section of it, may be computed from equation (2). ' Estimating Method Estimating methods are often used, especially where approximate figures are desired and time does not permit of more elaborate figures. Such methods are really the result of practical experience and are of value only in proportion to the experience of the user. There are, how ever, certain of these short cuts which are of value. - The temperature will drop approximately F per grain of water evaporated per cubic foot of^air (measured at 70 F) or approximately 0.62 F per lb of air at any temperature. Air will drop 55 F^per'bubic foot for each Btu extracted. Generally air will absorb from 2 grains to 5 grains per cubic foot of air in one passage through an air dryer, depending on the temperature and the degree of contact with the material. The amount of steam required to evaporate a pound of water will vary from 1H lb to a more usual figure of from 2J4 to 3 lb of steam per pound of water evaporated. 743 American Society of Heating end Ventilating Engineers Guide, 1936 DRYER ARRANGEMENT AND CONSTRUCTION Outside handling and storage space usually is an important considera tion in dryer design. Continuous dryers have an advantage in this respect since they provide storage for a considerable proportion of the material in process, while for charge dryers enough outside space must be provided to handle at least one full charge awaiting the dryer and one full charge upon removal. The more rapid the drying operation, the more efficient must be the handling facilities, in order to hold operating costs to a minimum and to keep the dryer operating at maximum capacity. An important consideration in construction is to provide tight, well insulated doors which can easily be opened and closed, with minimum labor and loss of time. Fire resistance of doors is also important, in case of outside exposure to fire risks. Insurance rates must be considered in their relation to fire protective arrangements such as automatic sprinklers, fire doors and walls, steam jets for use in smothering fires that may start inside the dryer, etc. Ceilings of dryers should be as flat as possible and the space between the material and the walls and ceiling should be held to a minimum. A factor often overlooked is that of suitable provision for ventilation of the space around the dryer openings so that warm moist air which may escape from the dryer when the doors are opened, may be carried away before it has a chance to condense on the ceiling or windows of the buildings in which the dryer, is located, or into which it opens. Convenient arrangements for the operator should also be provided where tests can be made, records kept, and clothes changed, in case it is neces sary for the operator to work inside the dryer. . EXPERIMENTAL TECHNIQUE One vitally important phase of dryer design has been ignored in the preceding discussion, namely, the time required to dry the stock, or, what is equivalent to the same thing, the size of the dryer, and the character and extent of the contact surface between the stock and the air. In general, this cannot be determined except on the basis of experimental data on the specific material to be dried. The source of such data may either be the known performance of actual commercial drying installations handling the same stock or direct experimental determinations in the laboratory. Data of this type for many materials is given in Table 1. >. Where it is necessary to determine drying conditions and rate in the laboratory, it is vitally important'to properly control the experimental conditions. Where possible, the material upon which the experiments are made should have the same shape and size as that to be treated com mercially. Furthermore, the conditions of exposure to the drying air, the temperature and humidity of that air, and its velocity and distribution over the material should be identical with those used in the full scale operation. Where the commercial operation is by batch, it is relatively easy to duplicate commercial conditions in the laboratory. However, where continuous operation is intended, it is'usually difficult to build a continuous experimental dryer. In such a case, a preliminary diagram of the type of Fig. 4 should be constructed and the drying conditions of the batch experimental operation controlled in the laboratory to conform to 744 Chapter 41--Drying the humidity moisture content relationship of the ultimate continuous operation. In this way, dependable data on the drying rate can be obtained in the laboratory. - As understanding of the mechanisms of drying and of the drying charac teristics of the material to be dried, is of the utmost importance in designing successful and economical dryers, especially in the interpretation and extrapolation of plant and laboratory test data. Air velocity has an important influence on the rate of drying in the constant rate period and in the first zone of the falling rate period, but in the second zone of the falling rate period, the rate of diffusion of water to the surface controls the drying, and hence increasing the air velocity past the surface can have little effect on the rate of drying. REFERENCES Commercial Drying Apparatus, by L. P. Dwyer (A.S.H.V.E. Transactions, Vol. 22, 1916, p. 479). Artificial Drying with Special Reference to the Use of .Gas, by G. C. Shadwell (A.S.H.V.E. Trans actions, Vol. 23, 1917, p. 231). Drying by Evaporation, by F. R. StiU (A.S.H.V.E. Transactions, Vol. 23,1917, p. 255). Drying in Industrial Plants, by J. O. Ross. High Temperature Drying, by Burt S. Harrison (A.S.H.V.E. Transactions, Vo], 24, 1918. p. 7). The Temperature of Evaporation, by W. H. Carrier (A.S.H.V.E. Transactions, Vol. 24, 1918. p. 25)Commercial Dehydration, by J. E. Whitley (A.S.H.V.E. Transactions, Vol. 26, 1920, p. 551). Drying as an Air Conditioning Problem, by A. W. Lissauer (A.S.H.V.E.' Transactions, Vol. 27. 1921. p. 251). . - .. A Chronological Survey of Drying and Dryers, by J. E. Bolling (A.S.H.V.E. Journal, October, 1921, p. 715). . Modern Drying Machinery, by H. B. Grenshaw, London, 1926. The Kiln Drying of Lumber, by A. Koehler and R. Thelen, New York, 1926. Drying, by W. H. Carrier {Marks' Mechanical Engineers Handbook, 2nd edition, 1924). Drying, Kent's Mechanical Engineers Handbook, 10th edition, 1923. Calculations for Drying Design, by Grosvenor (Transactions, A. I. Chem. Eng., 1908, p. 184). ' The Rate of Drying Solid Materials, by J. Lewis {Ind. Eng. Chem., 1921, p. 427). Principles of Chemical Engineering, by Walker, Lewis, McAdams, 1923, (Chapters 12 to 16 on Evapora tion, Humidity and Drying). The Kiln Drying of Lumber, by H. D. Tiemann (Lippincott, 1920). - Drying by Means of Air and Steam, by E. Hausbrand (D. Van Nostrand &* Co., 1901). . Principles of Drying Lumber and Humidity Diagram, by H. D. Tiemann (Forest Service Bui. 104. 1912). Symposium on Drying. Articles by W. K. Lewis, W. H. Carrier, A. E. Stacey and Fleming, R. G. Metz, G. B. Ridley, C* O. Lavett, D. J. Van Marie (Jour. Ind. Eng. Chem.). . '' The Drying of Solids, by T. K. Sherwood (Bui. Mass. Inst. Tech., Nos. 237, 247 and 258). ' Drying, by Perry (Chemical Engr. Handbook). Adiabatic. Drying of Hygroscopic Solids, by A. M. McCready, and W. L. McCale (Trans, Am. Insl. Chem. Engr., 1933). . PROBLEMS EV PRACTICE 1 0 What is meant by an adiabatic dryer? A dryer in which all of the heat required for evaporation is furnished only by the heat in the circulating air; *. 2 # What other broad classes of dryers are used commercially beside adiabatic dryers? , Dryers where the heat is furnished by contact with a heated surface, by radiant heat, by electrical induction or by a combination of any of these sources with heated air. 3 What makes a commercial adiabatic dryer differ from a theoretical one? The word adiabatic means no heat lost to the outside and that the sensible heat lost by the air is equal to the latent heat of the water evaporated. In an actual dryer, the solid containing the water, and the water itself must be heated to the temperature of evapora- , ` ' 745 American Society of Heating and Ventilating Engineers Guide, 1936 tion, before evaporation can begin. Radiation losses from the dryer enclosure is the other factor causing deviation from the theoretical adiabatic process. 4 What is a Zone Dryer? This term refers to a continuous dryer where the drying medium is divided into two or more sections, in order to have better control of the temperature and humidity gradients through the dryer. 5 i What is meant by high and low temperature drying? High temperature drying refers to an evaporator process where the temperature used is above the boiling point of water; 212 F. Low temperature drying utilizes tem peratures under 212 F, the range in which humidity is an important consideration. 6 How may air for high temperature drying be obtained? By direct oil or gas fired heaters, by indirect oil or gas fired heaters, by hot circulated oil, by high pressure steam, or by electric heaters. 7 What is meant by the critical point or critical moisture content? The point in the drying of a hygroscopic substance where all of the free moisture has been evaporated and after which the water is all in'the combined or bound state. It is the dividing point between the constant rate drying period and the falling rate. Shrink age of the material, if subject to shrinkage, will begin to occur at this point. 8 What is equilibrium moisture content? The moisture content of a hygroscopic material in the presence of air at a given tem perature and humidity which will remain constant no matter how long the material is exposed. The vapor pressure of the bound water in the material is equal to the vapor pressure of .the surrounding air at this point. 9 If a material enters a dryer containing 70 per cent water and 30 per cent solids, and leaves the dryer with 10 per cent water and 90 per cent solids, (a) what is the evaporation per pound of dried product? (b) What is the evapora tion per pound of bone dry material? a. 90 -- 1 = 2 lb water' per pound dried product. 70 b. Water entering = jq = 233 per cent on bone dry basis. Water leaving = = 11 per cent on bone dry basis. 'Water evaporated 222 per cent on- bone diy basis. Evaporation = 2.22 lb water per pound bone dry material. 10 What items must, be included in a calculation of the dryer heat require ments? ' a. Heating water to be evaporated from the entering temperature to the temperature of evaporation. ' b. Evaporating water to be removed. c. Superheating evaporated water from the temperature of evaporation to the exit temperature of the air. . ' d. Heating material from entering to leaving temperatures. .. e. Heating residual water from the entering to the leaving temperatures. /. Heating conveyor or other supporting materials. g. Radiation losses through the enclosure. h. Sensible heat in the exit air. . ' 746 Chapter 42 MOTORS AND THEIR CONTROL Direct Current Motors, Alternating Current Motors for Single Phase and Polyphase, Special Applications, Classification of Motors, Manual Control, Automatic Control, Pilot Controls, Direct Current Motor Control, >Squirrel Cage Motor Control, Multispeed Motor Control, Slip Ring Motor Control, Single Phase Motor Control THE commonest form of prime mover is the electric motor, which is available in a large number of types for the various services to which it may be applied! The equipment for starting, controlling and protecting these-motors varies with the type and with the functions it is desired to attain. Motors used for heating, ventilating and air conditioning ap plications may be divided into two general classifications as follows: 1. For use with direct current. 2. For use with alternating current. DIRECT CURRENT MOTORS There are three types of direct current motors available: 1. Shunt Wound. 2. Compound Wound. 3. Series Wound. ' - Shunt Wound motors are suitable for application to fans, centrifugal pumps, or similar equipment, where the amount of starting torque re quired is relatively small, for the majority of applications are used in the field of heating, ventilating and air conditioning. They may be used on reciprocating pumps and compressors, if started under unloaded con ditions. . Compound Wound motors are required for application to compressors, stokers, reciprocating pumps when started under loaded conditions, and also when applied to similar equipment where high starting torque is required. Whenever frequent starting makes high starting and accelerat ing torque desirable, or where sudden changes of load are encountered, compound woVind motors are used. . Series Wound motors find only limited application in a few special cases and are available in only a limited range of sizes. 747 American Society of Heating and Ventilating Engineers Guide, 1936 Direct current motors are available with speed characteristics of four types: 1. Constant speed. 2. Adjustable speed. 3. Adjustable varying speed. 4. Varying speed. ' Constant Speed motors may be shunt wound or compound wound. Shunt wound motors have a nearly flat speed-load characteristic, with a regulation of 12 per cent for 5 hp and smaller and 10 per cent for 7)4 hp and larger, based on full load speed. Compound wound motors have a speed regulation over the range from full load to no load of not more than 25 per cent, based on full load speed. Adjustable Speed motors are usually shunt wound since it is impractical to maintain the proper relation between the shunt and series fields of compound wound motors when wide variations of the field strength are required to obtain the speed adjustment. . Adjustment of the speed of. shunt wound motors is obtained by field control, with the minimum or base speed at full field strength and higher speeds at reduced field strength (obtained by adding resistance in the field circuit). The speed regulation from no load to full load will not exceed 22 per cent for 2 to 5 hp; nor 15 per cent for 7)4 hp and larger. Below 2 hp, the regulation may exceed 22 per cent. If closer speed regulation is required, specifically wound motors must be obtained. Practically constant horsepower output is obtained at all speeds up to a ratio of 2 to 1. For higher speed ratios, the horsepower rating at the minimum speed is less than at the maximum speed, this difference varying with the speed ratio. High efficiency is maintained over the entire speed range. Most listed constant speed motors are suitable for operation up to a speed ratio of 2 to 1 by the use of proper control equipment. Adjustable Varying Speed motors may be either shunt or compound wound and speed adjustment is obtained by adding resistance in series with the armature. The speed thus obtained is always below the rated speed. Any standard shunt or compound wound constant speed motor may be used in conjunction with the proper armature resistor. The usual range of speed reduction is 50 per cent. The speed obtained for any setting of the resistor depends on the load of the motor and will vary with this load. \ The speed regulation at high speed is comparable to a constant speed motor, but becomes poorer as the speed is decreased. When operating at reduced speed, an~ increased torque requirement which the motor could easily handle at rated speed is easily-sufficient to stall the motor; for example, a motor operating at two-thirds speed would be stalled by a torque about 50 per cent in excess of the normal requirement. .. The efficiency of the motor is reduced as the speed.is reduced, since the loss in the resistor is greater at lower speeds. Speed reductioji by armature control is usually selected where: 1. A wide speed range is not required. 2. Close speed regulation is not necessary. 748 ` Chapter 42--Motors and Their Control 3. Operating time at reduced speed is short. 4. Operating load at reduced speed is small so that the reduced efficiency can be ignored. Varying Speed motors are series wound and the speed varies with the load on the motor. They should be used where: 1. The load is practically constant or increases with speed. 2. The motor can easily be controlled by hand. They should not be used where there is a possibility of operation without load or at a reduced load, as the speed of the motor may become dangerously high. . .. For shunt wound motors with full field strength, the starting torque varies almost directly with the starting current, which is dependent on the resistance in the armature circuit. With varying positions of the starting rheostat, it is possible to obtain a wide range of starting torque, within the limits of starting current permitted by the power company. A compound wound motor requires somewhat iess current for the same starting torque. The maximum torque is limited by commutation. ALTERNATING CURRENT MOTORS Alternating current motors may be divided into two main groups, namely, (1) those operating on single phase current, and (2) those oper ating on polyphase current. 1. Single phase motors are available in three common types: a. Repulsion start, induction run. b. Capacitor type. . c. Split phase. - 2. Polyphase (2 or 3 phase) motors are available in four common types: o. Squirrel cage induction motor. b. Automatic start induction motor. c. Slip ring, wound rotor induction motor. d. Synchronous motor. ' Where the public utility supplying the current determines that a particular installation should be served with polyphase current, it is generally understood that the major portion of the motors will be for polyphase current, although it . is commonly acceptable for the smaller motors to be single phase. This will in general, limit the use of single phase current to the smaller motor ratings and the polyphase to the larger motors. . Single Phase Motors . . Repulsion start, induction run motors are suitable for use with fans, centrifugal pumps, reciprocating pumps and compressors (started loaded or unloaded) since these motors have relatively high starting torques and low starting currents. This type of. motor has a constant speed character- ristic. The motor has a commutator and brushes to obtain starting and an integral automatic governor for changing to an induction motor when nearly up to speed. . American Society of Heating and Ventilating Engineers Guide, 1936 The capacitor type motor is available only in the small and fractional horsepower ratings. It is manufactured in three types: 1. Capacitor Start, limited to J4 hp and smaller, using the condenser in starting and disconnecting the condenser by means of an automatic governor when operating at full speed. The starting torque is low; used for direct connected service only. 2. Capacitor Start, Capacitor Run having a condenser in the circuit while starting and running at speed. An auto transformer supplies high voltage while starting and normal voltage when the motor is operating at full speed. The change is accomplished, by an automatic governor in the motor. These motors have starting and operating characteristics suitable for the operation of the various types of air conditioning equipment within the range of sizes available. This type of motor has a constant speed characteristic. - . The choice between the capacitor motor and repulsion, induction motor is largely a matter of personal opinion. Adjustable speed motors in this type are available where low starting torque is satisfactory. ' These motors do not have a governor but act as capacitor start and capacitor run motors with a fixed condenser in circuit at all times in addition to an auto transformer arranged with several taps, a few of which are selected to give the desired variation in speed. 3. Capacitor type motors with medium starting torque are also available in the construction described previously. Split phase motors are available in sizes 34 hp and smaller and should be used where high starting torque is not required (such as small fans, pumps and oil burners). The starting current is higher than for either the repulsion, induction, or capacitor motors. A special type, with enclosed end brackets and a thrust bearing, is available up to 34 hp for use with propeller fans mounted on the motor shaft. This type of motor has a constant speed characteristic. Polyphase Motors Squirrel cage induction motors are available in three types, and a full range of sizes: ' 1. The normal torque, normal starting current squirrel cage motor has close speed regulation, high efficiency, high power factor, high pull-out torque, high starting torque and is suitable for general purpose applications. This motor, has a large current inrush and a low starting current power factor. It operates with these characteristics only when started directly across the line on full voltage. When central stations' require cuiyent limiting starting equipment on such motors, the starting torque.is less. ' Current limiting hand operated compensators are standard equipmenrand have 50, 65 and 80 per cent. taps, the 65 per cent tap being regularly connected when the compensator, leaves the factory. ,, . 2. The normal torque, low starting current squirrel cage motor has approximately the same torque as the normal current motor, but the starting current is approximately 20 per cent less than the normal torque motor on full voltage and well within the recom mended EEI limits on 30 hp sizes and smaller. This motor lends itself to automatic or remote control because no current limiting starting equipment is necessary for 30. hp and smaller sizes. A magnetic starter with low voltage and thermal relay overload protection gives the most satisfactory service. . These switches may be controlled by push button, thermostat or pressure relay to meet the requirements of any particular installation. . 3. The high torque, low current squirrel cage motor has a starting torque approxi mately 25 to 50 per cent greater than the normal torque motor on full voltage with starting current approximately 10 per cent less than the normal torque motor started on 750 Chapter 42--Motors and Their Control full voltage, but within the required limits on 30 hp sizes and smaller. These motors are also started directly across the line on full voltage through a magnetic starter or other approved starting device. These three types of motors are also available in two, three, or four speed designs with variable torque, variable horse power or constant torque characteristics. Two speed motors may be either single, or two winding; three speed motors are single, two, or three winding; and four speed motors are two, three, or four winding. When a motor is wound with a winding for each speed, better operating characteristics are obtained because no sacrifice is made for the other speed and operating characteristics approaching single winding motors may be expected. Frequently, multispeed motors lend flexibility to an installation that cannot be obtained in any other way. , Multispeed motors are started, through magnetic starting equipment with overload and low voltage protection, directly across-the-line with compelling relays to insure starting on low speed regardless of the ultimate running speed. Starting on low speed limits the starting current to the starting current of the low speed winding and consequently lowers the maximum demand. Often where the central station requires current limiting starting equipment for the normal torque, normal starting current motor, it is advisable to use the normal torque low starting current multispeed motor. It is apparent from these motor characteristics that a squirrel cage motor may be selected for operating any. air conditioning and allied equipment. Automatic start induction motors are constructed with two windings on the rotor, One of which is a high resistance, squirrel cage winding used in starting and gives a high starting torque. A centrifugal mechanism within the motor switches to the second low resistance winding when the motor comes up to speed, thus obtaining running characteristics.equal to the normal torque, normal current squirrel cage motor. The power factor of the starting current is high. Split ring, wound rotor motors are built for two classes of service, con stant speed and adjustable variable speed.. The motors are identical in . each case and use the same primary control, the only difference being in the secondary control. Slip ring motors for constant speed service are used where high starting torque with low starting current is required for bringing heavy loads up to speed. The resistance is in the secondary or rotor circuit, only when starting, and is short circuited when the motor is up to speed. For adjustable vailing speed service, part or all of the secondary controller resistance is in the circuit whenever the motor is operating below full speed. The speed obtained with a given resistance in the secondary circuit is dependent on, and changes with, the load on the motor. The horsepower developed by the motor is approximately pro portional to the speed, whereas the power required by the motor is practically the same at reduced speed as at full speed, hence the efficiency at reduced speeds is much lower than at full speed. ' Synchronous motors are ordinarily used only where there is a necessity for, or advantage in, obtaining power factor correction. It is advisable to consider each application as a special ease. 751 ' American Society of Heating and Ventilating Engineers Guide, 1936 Current Type Table 1. Classification of Motors Speed Charac teristics Starting Torque' Starting Current Hp Range Constant Speed Drives Type op Application See Footnotes 1. Shunt Direct 2. Compound 3. Series Constant Medium Medium Constant or Variable High Medium Variable High Medium All (a) Fans and (c) Centrifugal . Pumps All (6) (c) (e) Reciprocating Pumps and frequent or hand starting Small (d) Fans direct connected Poly phase 4. Squirrel Cage Constant Medium High All (a) Fans and General Purpose 6-8 Times (c) Centrifugal Pumps 5. Squirrel Cage Constant Medium Medium Medium (a) Fans and Medium Torque 5-6 Times Small Centrifugal Pumps 6. Squirrel Cage High Torque Constant High Medium Medium 5-6 Times Small (b) Reciprocating Pumps (e) and Compressors started loaded 7. Slip Ring Constant High Low All (a) and Hoists Wound Rotor 1-3 Times (b) Reciprocating Pumps * ' (c) and Frequent (e) or Hand Starting 8. Synchronous High Speed Constant Medium Medium Medium (a) Fans and 5-7 Times / Large Centrifugal Pumps 9. Synchronous Low Speed Constant Low Low Medium 3-4 Times Large \ (o) Reciprocating Compressors Starting Unloaded 10. Repulsion Induction Single Phase 11. Capacitor 12. Capacitor ' 13. Capacitor Constant High Medium Medium (a) Fans Small (b) Pumps and Compressors . Constant Low Medium Small (d) Fans--direct All and Constant Medium (5-8 l imes Fractional (a) Fans--belt Constant High () Compressors and Pumps 752 Chapter 42--Motors and Their Control Current Table 1. Classification of Motors--(Continued) Type Speed Charac teristics Starting Torque Starting Current Hp Eanqe Type op . Application See Footnotes Adjustable Speed Drives / Direct 14. Shunt Field Adjustment 15. Shunt Armature Resistor Constant Medium Medium Variable Medium Medium All . All (a) Fans and (ej Centrifugal Pumps (a) Fans and (e) Centrifugal Pumps PolyPHASE 16. Squirrel Cage Regrouped Poles Constant Medium Multi- or High speed 17. Slip Ring Secondary Resistance Variable ' High High Low All (a) Fans and (6) Pumps All (a) Fans and (b) Centrifugal Pumps Single Phase 18. Capacitor Variable Transformer Adjustment . _ Low Low Fractional (d) Fans aApplications: a. Drives having medium or low starting torque and inertia (WR*) 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 hand starting (large WR*) requires a higher starting and accelerating torque. d. Fans direct connected. . e. Stoker drives. ' SPECIAL APPLICATIONS A few applications of motors may require special constructions such as splash proof, explosion proof, fully enclosed, and self-ventilated to meet hazardous or special duty conditions. These requirements are frequently encountered in certain industrial applications, in which cases it is neces sary to select the motors from the viewpoint of service conditions, as well as the required operating characteristics to meet the demands of the machines being driven. The general classification of motors used for heating, ventilation and air conditioning is shown in Table 1. CONTROL EQUIPMENT FOR MOTORS In selecting control for alternating and direct current motors it is necessary to determine whether the installation is to be operated by manual or automatic control. The available controls and the function of each group of apparatus may be outlined as follows: 1. Manual Control: a. To establish current. (1) Snap switch. (2) Knife switch. (3) Manually operated contactor. (4) Drum switch. 753 . American Society of Heating and Ventilating Engineers Guide, 1936 b. Establish current and add overload protective device. (1) Snap switch with overload element. (2) Knife switch with fuse or thermal cutout. (3) Manual contactor with overload protective device; also reduced voltage starting compensator. (4) Drum switch with overload protection. c. Establish current and add overload and low voltage protective devices. (1) Not used. (2) Not used. ' (3) Manual contactor or reduced voltage compensator with overload and low voltage release. (4) Drum switch equipped with latch coil to give low voltage release. 2. Automatic Control: a. To start on full voltage. (1) Without overload device. (2) With overload device. (3) With combination overload device and knife switch. b. Reduced voltage starting. (1) Primary resistance type starter. (2) Auto compensator type. (3) Reactance type. . PILOT CONTROLS In selecting pilot control devices to operate in conjunction with either manual or automatic motor control, it is necessary that they be classified as follows: 1. Two Wire Control. Most thermostats, float switches, and pressure regulators, provide two wire control which gives low voltage release. A three position pilot switch can be used in connection with this method and thus provide manual control. With a low voltage (12 or 20 volt) control circuit it is desirable to use a low voltage thermostat. When this type of thermostat is used it will be found that a saving in the wiring cost results. When using the low voltage thermostat on a control circuit a relay and trans former panel should be used instead of the low voltage coil on the starter. 2. Three Wire Control. Momentary contact start and stop push button stations are usually furnished as standard accessories with automatic starters, which gives low voltage protection. This control cannot be used in combination with two wire pilot devices. In selecting manual control for an alternating or a direct current motor, the common practice is to locate the control near the motor. When the control is installed at the motor, an operator must be present to start and stop or change the speed of the motor by operating the control mechanism. . Frequently manual control is 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 unitr heaters, small blowers, and room coolers in an air conditioning system. In other cases manual control in the form of drums, when used with multispeed motors, is only used as a speed setting device with the starting and stopping functions operated automatically through thermostats, and pressure switches. Because of the increasing complexity of air conditioning systems, heating, ventilating and air conditioning equipment is being operated on 754 Chapter 42--Motors and Their Control automatic control with less dependence on manual operation and regu lation. ' Automatic control of motor starters may be accomplished by the use of remote push button stations by a thermostat, float switch, pressure regu lator or other similar pilot devices. An added advantage of automatic control is that the main wiring for the starter may be installed near the motor, while the starter may be operated by a control device located else where. In the majority of air conditioning installations, requiring motors 1 hp and larger, two or three phase alternating current is usually supplied. DIRECT CURRENT MOTOR CONTROLS Air conditioning installations using direct current power are now only used where alternating current is not available. Direct current motors are always started through starters, which are devices using a resistance to be put in series with the armature circuit during starting only, the resistance being gradually cut out as the motor comes lip to speed. The starting current is held within safe limits by the use of the resistance. The speed of a direct current motor may be regulated by the following methods: 1. Speed regulation by field control--by using a device with resistance to be put in series with the field winding.. After the motor has been started to be used to increase the speed of the motor above full field speed. 2. Speed regulation by armature control--by using devices with resistance to be put in series with the armature circuit to be used to reduce the speed of the motor below full field or normal speed. 3. Combinations of field and armature control, so that the starting, field control, or armature control may be combined in a single unit. Field control is usually preferred, depending on the size of the instal lation. For example, if a direct current motor were required with speed regulation between 1200 and 600 rpm, a choice of supplying a 1200 rpm motor with armature control or a 600 rpm motor with field control, both giving the same speed variation would be possible. While the 1200 rpm motor with armature control is lower in first cost than the 600 rpm motor with field control, the cost of operating the 600 rpm motor with field control is less and will save the difference in first cost over a period of time depending on the size of installation. A wide speed variation can be easily obtained in a direct current motor by using a combination of field and armature control. SQUIRREL CAGE MOTOR CONTROL To meet the requirements of various drives of an air conditioning system, three types of squirrel cage, two or three phase motors may be used: 1. Normal torque, normal starting current. 2. Normal torque, low starting current. 3. High torque, low starting current. Because of the large current inrush of the normal torque, normal starting current motor, central stations usually require current limiting 755 American Society of Heating and Ventilating Engineers Guide, 1936 starting equipment on such motors above 5 hp. To meet the starting current requirements, manual or automatic current limiting starting com pensators'are used. These compensators are equipped with 50, 65 and 80 per cent voltage taps, the 65 per cent tap being regularly furnished when the compensator leaves the factory. Motors 5 hp and smaller have starting currents within the requirements of central stations and manual or magnetic, full voltage control may be used. The normal torque, low starting current motor has a starting current which is approximately 20 per cent less than the normal current motor on full voltage and well within the required current limits on 30 hp sizes and smaller. This motor, therefore, lends itself to across-the-line control because no current limiting equipment is necessary. In selecting motors for fans, pumps, or blowers, it should be noted that while the cost of the normal starting torque, low starting current motor is higher, the cost of full voltage control is lower,so that the total cost of low starting current motors with across-the-line control is lower. A magnetic starter with low voltage and thermal overload protection gives the most satisfactory service. These switches may be controlled by remote push button stations, thermostats, or pressure switches to meet the requirements of any particular installation. The high torque, low starting current motor has a starting current approximately 10 per cent less than the normal torque, low starting cur rent motor when started on full voltage. These motors, most commonly used on compressor drive, can be started directly across-the-line with manual or magnetic starters. MULTISPEED MOTOR CONTROL To make an installation more flexible, multispeed motors are available with two, three or four speed designs, with variable torque, constant torque or constant horsepower characteristics. Multispeed may be started by means of manual or magnetic starting equipment. When using automatic magnetic control with two, three, and four speed separate winding or consequent pole motors, control is 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, which is known as selective speed control. It is commonly used in thh smaller theatre installations where the fan and motor is located back stage and the speed control is located in the lobby. Magnetic multispeed motor controllers may also be provided with a compelling relay which makes it necessary that the operator press the first speed button before regulating the motor to the desired speed. This assures the operator that the motor is always started at low speed before the motor is adjusted to one of the higher speeds. Starting on low speed limits the starting current to the starting current of the low speed winding, and therefore, permits the use of motors in sizes larger than ordinarily permitted by central stations for full voltage starting. . Timing relays, which provide for automatic acceleration, may be used for control. With the automatic acceleration feature, it is only necessary 756 Chapter 42--Motors and Their Control to press the button for the desired speed. The motor will always start in low speed and automatically step up to the desired speed. Where the change of speeds does not occur at regular intervals, and where it is only necessary to change from one speed to another to take care of seasonal requirements, a manual drum speed selector may be used. This drum is used to select the proper motor speed while an automatic starter is used to start and stop the motor. The smaller size speed selector drums rated 10 hp at 200 volts and smaller may also be used as a motor starter to make and break the current, as well as, serving as a speed selector device. Reversible or non-reversible drums may be supplied depending on the requirements of the installation. In the large size drums, a separate contactor must be provided to make and break the current. The contactor may be any approved starter. Overload and low voltage protection may be accomplished by using a magnetic starter. No push button station is required, the handle switch on the drum having the same characteristics as a three wire push button station. In selecting two speed motors for fan, pump, blower, or compressor drive it will be found that the two winding motors are more expensive than the single winding. The control for two speed, two winding motors is more economical and the combined price of the motor, and contactor is only slightly higher. Because of the better performance of the two speed motor and the factor of safety in having two independent motor windings, the increased cost is considered worth the difference. SLIP RING MOTOR CONTROL When close speed regulation and. low starting current is required slip ring or wound rotor motors are used. Slip ring motors are built for two classes of service,, constant speed and adjustable varying speed. The motors for the two classes of service are identical, the only difference being in the secondary control used with the motors. Control for both primary and secondary of a slip ring motor is required. The primary control for a constant or adjustable speed is the same type as used with squirrel cage motors. Manual or magnetic starters, acrossthe-line type, may be used depending on the installation. The starting current and starting torque of a slip ring motor are almost entirely dependent on the amount of resistance in the secondary control and in the manner in which the secondary control is operated. The National Electric Manufacturers Association has adopted service classi fications which allow a selection of resistors permitting a starting current on the first contact of resistance varying from approximately 25 per cent of full load current to approximately 200 per cent of full load current or more, and permitting the resistor to remain in the secondary circuit of the motor for a period varying from not more than 15 seconds during an interval of operation from 4 minutes to continuous. Speed regulation of a slip ring motor is obtained by inserting resistance in the secondary circuit and usually provides for a 50 per cent speed reduction when the motor takes its full rated current at normal speed. 757 American Society of Heating and Ventilating Engineers Guide, 1936 As resistors are supplied for both fan duty and constant torque duty, care should be taken in selecting the proper resistors. . Slip ring motors when used with centrifugal pumps and fans should have fan duty resistors. Because of the low current inrush of the fan and pump load a starting resistor NEMA classification No. 15 may be used. For speed regulation resistor, classification No. 93 should be selected. On a compressor drive using an unloader, a constant torque resistor classi fication No. 15 should be used. If the compressor is started under load, NEMA classification No. 56 or 76 are used. For constant torque speed regulation, resistor No. 95 is used. SINGLE PHASE MOTOR CONTROL Where three phase current is not available or where single phase opera tion is preferred, then single phase repulsion induction, capacitor type or multispeed single phase motors may be used. Since the starting currents of all single phase motors are designed to operate within the recommended starting current rules of the EEI, across-the-line type starters are avail able as follows: 1. Enclosed two pole manually operated motor starters with thermal overload protection. 2. Enclosed two pole automatic motor starter operated by a push button, thermostat or similar device, with thermal overload relay and low voltage protection. ' 3. Where the requirements of the central station supplying the power are such as to necessitate a reduced starting current, a manual or magnetic resistance type starter with low voltage protection is commonly used. In selecting across-the-line control for single phase capacitor type motors it is usually very desirable to use three pole across-the-line starters. Control for multispeed, single phase capacitor motors may be selected from tables on three phase rating when consideration is given to the increased current and the necessary switching of connections. PROBLEMS IIV PRACTICE 1 When motors are being considered as prime movers, what are some of the basic considerations that determine the final selection of the correct unit? a. The kind of current available for driving the necessary motors is a primary con sideration. There are two groups of motors available for driving the equipment on any job, which are the direct current type or alternating current type. The proper group selection depends entirely on the current available. b. It is also necessary to decide whether constant speed or variable speed operation is desired. . c. Consideration must also be given to the type of service required. 1.-Whether variable torque or constant torque motors will be required. 2. Whether a high starting torque is required or whether a relatively small starting torque is required. .. 2 # When using direct current motors: a. What three types are available as regards their windings; b. What four types are available with reference to their speed characteristics? a. Shunt wound, compound wound, and series wound. b. Constant speed, adjustable speed, adjustable varying speed, and varying speed. 758 Chapter 42--Motors and Their Control 3 With direct current motors as prime movers what type would you use: a. For driving a fan; b: For driving a compressor? o. A fan requires a relatively small starting torque, therefore, a shunt wound motor would be ideal for this type service. b. A compressor has a constant torque, therefore, a compound wound motor would be the proper selection for this duty. 4 What is one of the important factors that should be taken into account when a series wound direct current motor is being considered? With a series wound motor the speed varies with the load, therefore this type should never be used where there is a possibility of the motor operating without being loaded. The resultant high speed may prove to be dangerous. 5 With the use of alternating current motors what two groups are generally considered? Motors using single and polyphase power supply. 6 Under the alternating current group of motors what common types are available: a. For single phase duty; b. For polyphase duty? a. Repulsion start, induction run, capacitor type, and split phase. b. Squirrel cage induction, automatic start induction, slip ring wound rotor induction, and synchronous type. 7 What is the most commonly used of the polyphase motors? The squirrel cage induction motor is the type most generally used for ordinary applica tion. 8 With the use of squirrel cage motors what speed characteristic is available and what construction is used to make these more flexible? The squirrel cage motor is a constant speed unit and cannot be used for variable speed operation. To make this type of motor more flexible, multispeed units are used quite frequently. These units may be single winding for the two speed unit or for different number of windings depending upon the number and combination of speeds required. For two speed single winding units the second speed is always one half of top speed. 9 Differentiate between synchronous speed and full load speed of a motor. Synchronous speed is the theoretical or no load speed. With the induction motor there is a certain amount of slip depending upon the load. As a rule, at full load, the speed is approximately 96 per cent of synchronous speed, however, motor manufacturers generally list full load speeds on their motor name plates. The synchronous type of motor has a full load speed which is the same as the synchronous. 10 What are the general requirements generally recommended by the power company with reference to connecting polyphase motors to the power line? For motors five horsepower and smaller, normal torque, normal starting current type of units can be connected directly to the line. ' For motors thirty horsepower and smaller, normal torque, low starting current type of units can be used with across-the-line type of control. Above these sizes it is necessary to furnish current limiting starting compensators. It is always advisable to check with local power companies as there are no standards for connecting of loads on the power line and they are likely to vary with different power companies. . . 11 In controlling direct current motors what two methods are used, what speed ranges are obtained, and what is the relative efficiency of each method? In controlling direct current motors, resistance is placed in either the armature circuit or the field circuit. For armature control, the speed is reduced with the increase of re- 759 American Society of Heating.and Ventilating Engineers Guide, 1936 sistance. With the field control, the speed is increased with the addition of resistance in the field circuit. , For most listed direct current motors, it is possible to obtain operation up to a speed ratio of two to one with field control equipment. This type of control is used in con nection with shunt wound motors for best results. For speed adjustment by resistance in series with the armature circuit, a reduction of 50 per cent in speed can generally be obtained. This control can be used with either shunt or compound wound motors. The field control method of changing speeds on direct current ^motors is the most ef ficient. Due to the large current in the armature circuit, this method results in a high loss when the speed is reduced any appreciable amount. It is well to remember that with field control only constant horsepower output is obtained, therefore, care should be taken that the motor at normal speed is large enough to care for any increase in load as a result of speeding up the unit. . 12 t What reduction in speed is possible and how is it obtained when alter nating current slip ring motors are used? ' Speed variation in slip ring motors is obtained by inserting resistance in the secondary circuit. This generally allows for a 50 per cent speed reduction when it is fully loaded at normal speed. 760 Chapter 43 TEST METHODS AND INSTRUMENTS Pressure Measurement, Temperature Measurement, Air Move ment, Humidity Measurement, Carbon Dioxide Determination, Dust Determination, Flue Gas Analysis, Measurement of Smoke Density, Heat Transmission, Eupatheoscope Problems in Practice SEVERAL types of measuring apparatus are available for accurately determining the thermal capacity and air movement of gaseous vapors and homogenous materials. This chapter gives a brief description of the principal instruments used in connection with the proper control and testing of heating and air conditioning installations. PRESSURE MEASUREMENT Atmospheric pressure is usually measured by a mercurial barometer which, in its simplest form, consists of a glass tube about 3 ft long, closed at the upper end, filled with mercury and inverted in a shallow bath of mer cury. The pressure of the atmosphere on the exposed top of the mercury in the cistern supports a column of mercury in the tube to a height of about 30 in. Readings are taken of the'height of the column between the levels of.mercury in the tube and in the cistern. Atmospheric pressure is the same as the pressure exerted by this supported column of mercury, and, in pounds per square inch, is equal to its height in inches times 0.491, which is the weight in pounds of 1 cu in. of mercury. At latitude 45 deg and sea level, and at a temperature of 32 F, the atmosphere will support a column of mercury 29.921 in. in height. The pressure of 14.7 lb per square inch, derived by multiplying 29.921 by 0.491, is called standard or normal barometric pressure. Since the height of the barometer depends on the density of the mercury as well as on the pressure of the atmosphere, and since the density is dependent on the temperature, mercurial barometer readings should always be corrected for temperature. An aneroid barometer contains no liquid; it is portable but less accurate than the mercurial baro- meter. Atmospheric pressure in bending the thin corrugated top of a partially exhausted metallic box, or in distorting a thin-walled bent tube of metal, is made to move a pointer. Pressures above or below atmospheric are usually measured by means of gages which indicate the difference between the pressure being measured and atmospheric pressure at the same time and place. A gage which indicates pressures higher than atmospheric is known as a pressure gage, and a gage which indicates pressures lower than atmospheric is known as a vacuum gage. The most common type of these gages contains a flexible hollow metail tube of oval cross section, known as a Bourdon tube. When subjected to unequal inside and outside pressures, this tube tends to 761 American Society of Heating and Ventilating Engineers Guide, 1936 straighten out, and a pointer motivated by this straightening indicates the pressure difference on a suitably graduated scale. High vacuum readings such as are encountered in condenser and steam jet refrigeration practice are commonly obtained by the use of mercury column vacuum gages. When the readings obtained with the mercurial barometer and those with the mercury vacuum gage have both been corrected to 32 F, the difference in the two readings will give the absolute vacuum in inches of mercury. The following equation may be used to make corrections for temperature: where h = h [1 - 0.000101 (h - 01 h = height of mercury column corrected to temperature t. hi = actual height of mercury column. h = actual temperature of mercury column. 1 = temperature to which column is to be corrected. (1) A gage which indicates pressures slightly above or below atmospheric is known as a draft gage. It is essentially a U tube containing either water, kerosene, alcohol, or mercury, with one leg exposed to the air and the other connected to a point where the pressure is to be determined. When the pressure being read is equal to atmospheric, the level of the liquid in the legs will be the same, indicating a zero gage pressure. When a pres sure is applied to one leg, one side will fall and the other will rise an equal amount. The difference in height between the two liquid levels indicates the pressure expressed in inches of liquid used in the gage. Various forms of high sensitivity draft gages1 frequently called micro manometers are available for the measurement of small pressure differen tials and may be sensitive to pressures as small as 0.001 in. of water. These gages are often useful where measurements are to be made on pressure differentials less than 0.1 in. of water, although their total range may extend as high as 5 to 10 in. of water. TEMPERATURE MEASUREMENT In engineering work, mercurial thermometers are largely employed to measure the intensity of heat. These depend on the uniform expansion of mercury to indicate changes in temperature. An amount of mercury held in a sealed tube with a bulb at one end wilkrise to one definite level when immersed in melting ice, and to another definite level when immersed in boiling water. These two points are marked, and the space between them is divided into a number of equal portions, each of which is called a degree. In the Fahrenheit scale, there are 180 deg. thus obtained, while the centigrade scale has 100 and the Reaumur has 80. Like divisions are marked off on the column above and below these two determined points in order that a greater range of temperature may be read.. Thermocouples2 may be used to measure any range of temperatures up to 2,900 F. When two dissimilar metals are joined at two points and a 1Illinois Micromanometer, University of Illinois Engineering Experiment Station Bulletin No. 120, p. 91. iStudy of the Application of Thermocouples to the Measurement of Wall Surface Temperatures, by A. P. Kratz and E. L. Broderick (A.S.H.V.E. Transactions, Vol. 38, 1932). 762 Chapter 43--Test Methods and Instruments temperature difference exists between these junctions, an electromotive force will be developed. Its magnitude depends on the composition of the wires and the difference in temperature between the junctions. A poten tiometer or sensitive galvanometer of high resistance connected to the thermocouple will give a deflection which is a function of the temperature difference between the hot and cold junctions. Thermocouples con nected in series are called thermopiles. Thermocouples for the measure ment of high temperatures are calibrated with the aid of the known melting points of pure metals. Resistance thermometers are suitable for temperature measurements up to 1800 F. These thermometers depend for their operation on the change of resistance with temperature of a platinum, nickel, or copper wire coil, and they are calibrated in the same way as thermocouples. Pyrometers of various types may be used for temperatures above 500 F. The mercurial pyrometer is a thermometer with an inert gas, such as nitrogen or carbon dioxide, above the mercury column to prevent the mercury from boiling. The radiation pyrometer consists of a thermopile upon which the radiation from a hot source is focused by a concave mirror or lens. A sensitive galvanometer or portentiometer with a calibrated temperature scale indicates the thermo-electromotive force created by the heat on the thermopile. The optical pyrometer measures radiant energy by comparing the intensity of a narrow spectral band, usually red light emitted by the object, with that emitted by a standard light source (electric lamp). Thermo-electric pyrometers operate on the same principle as thermocouples. When measuring high temperatures, it is customary to hold the cold junction at room temperature and this may cause some error if the room temperature is above or below the calibration point. For extremely precise temperature measurements, the cold junction is usually immersed in melting ice to fix the cold junction temperature. Various forms of hand-operated and automatic cold junction temperature com pensators are also available. In the measuring of room temperatures care must be exercised to pre vent the results from being affected by the body heat of the observer, by drafts from doors, windows and other openings, or by radiant heat from some local source such as a radiator or wall. All glass thermometers should be mercury thermometers with engraved stems. The total gradua tions of the thermometers should be from 20 to 120 F, in one degree graduations. No ten degrees should occupy a space of less than one-half inch. The accuracy throughout the whole scale must be within one-half degree. The operator should take hold of the top and no part of the body, including the hand, should be nearer than 10 in. to the bulb. The thermometer should not be closer than 5 ft to any door, window, or other opening; should not be closer than 12 in. to any wall; and should bebetween 3 and 5 ft from the floor. A sling instrument should be used for extreme accuracy. Thermocouples or resistance thermometers may also be used for room temperature measurements, an advantage being that the operator can read temperatures from outside the room if desired, and thus eliminate the errors which might be caused by his presence close to the temperature measuring device. For measuring duct temperatures a duct thermometer should be used, with the bulb extending into the duct at least 6 in. When the thermo- of andAmerican Society Heating Ventilating Engineers Guide, 1936 meter is to be permanently located in the duct, a pipe flange or nipple should be used to receive the threaded portion of the thermometer stem. When the thermometer is not to be permanently located, a cork or rubber stopper may be placed around the stem to prevent errors from air leakage. Readings should be taken at various locations in a duct so due con sideration may be given to temperature stratification. Other forms of temperature measuring devices may be used, but the active part must be at least 6 in. from the duct wall. Recording instruments may be used for testing and for making con tinuous records of operation. Potentiometer and Wheatstone bridge recorders for thermocouples and resistance thermometers respectively may have accuracies of == 1^ per cent of their range, or, for example, to 1 F in a range of 0 to 300 F. This accuracy compares favorably with that of other forms of temperature measuring devices. MEASUREMENT OF AIR MOVEMENT The quantity, velocity and pressure of air moved by a fan or flowing through a duct or grille may be determined by various methods. The instruments in common use are the Pitot tube, anemometer, direct reading velocity meter, and Kata-thermometer, the latter being suitable for low air velocities and being commonly used for measurements at points where the air is not confined in a duct. Electrical anemometers are also available, operating on the principle of measurement of the variation ~ of resistance of a hot wire cooled to various degrees by air velocities past the wire. The use of calibrated nozzles, orifice plates, and Venturi meters are recognized methods, which, however, have little application in con nection, with ventilation practice. Pitot Tube This usually consists of two tubes, one within the other, which when properly held in the air stream will register the total or impact pressure and the static pressure, respectively. If these tubes are connected to opposite sides of a water column, or other type of manometer, the recorded pressure will be the differential or velocity pressure. Volume measure ments may thus be made in a duct of known area. Pitot tube measure ments are preferably used for air velocities exceeding 20 fps.. Volumetric determinations from Pitot tube readings should take into.account the barometric pressure and the temperature and humidity of the air measured. Air flow in ventilation practice is generally in the turbulent range. When stratification of velocity, vortex motion, or violent eddy currents of air in ducts exist, accurate velocity pressure measurements are difficult. To insure accuracy a straight section of duct from 5 to 10 times its own diameter is desirable in order to straighten out the air currents. If 'it is necessary to take Pitot tube readings in shorter sections of straight duct, the results must be considered subject to some doubt and checked accor dingly. For accurate work it is necessary to make a traverse of the duct, dividing its cross section into a number of imaginary equal areas and taking a reading in the center of each, the average of the velocities cor responding to these pressures giving the true velocity in the duct. 764 Chapter 43--Test Methods and Instruments Anemometer This instrument is delicate, and requires frequent calibration when accuracy is desired. The vanes of the instrument should never be touched and it should never be held in air having a velocity greater than that for which it is calibrated. Readings taken directly in a fan inlet or discharge are likely to harm the instrument because of excessive velocities. In duct measurements the same procedure is followed as for the Pitot tube. The anemometer usually reads directly in linear feet. To obtain the velocity in feet per minute, the reading must be divided by the elapsed time in minutes. The following procedure for obtaining anemometer readings is based on research conducted at Armour Institute of Technology in cooperation with the A.S.H.V.E. Research Laboratory3. Supply Grilles. The surface of the grille should be marked off into a number of equal areas approximately 6 in. square. A 4-in., anemometer should be used and should be held at the center of each section in contact with the grille (or as close as possible) for a period of time sufficient to insure an average reading. In the case of supply grilles, the instrument should always be held with the dial facing the operator. The average of the corrected readings should then be used in the following formula to obtain the flow in cubic feet per minute: ' Cfm = cv^ (2) - /. z where . V = average of corrected anemometer readings, feet per minute. A = gross area of grille, square feet. , a = net free area of grille, square feet. p = percentage of free area of grille expressed as a decimal. C = a coefficient that varies with the velocity from grille and may vary slightly . with type of grille. For average use, with supply grilles, C can be taken as 0.97 at velocities from 150 to 600 fpm, and as 1.00 at higher velocities. Particular care should be exercised in the case of long, narrow grilles. The nature of the approach sometimes results in there being a narrow strip along the top or bottom of the grille through which no air will be flowing. This may be detected by holding the anemometer completely , out of the air stream and then moving it slowly inward over the grille until . the vanes just start to move. The distance which the vanes extend over the grille opening at this moment will indicate the width of the dead strip. Only the remaining portion of the grille should be considered in making the calculations for gross and free area. Exhaust Grilles. The surface pf the grille should be marked off and readings taken in the same manner as with supply grilles, except that the instrument should be held with the dial facing the grille, and in contact with jt. The traverse should be taken at a uniform rate, allowing suf ficient time in each space to minimize the percentage of error. In the case of exhaust grilles it is found that the formula cfm = KVA (3) Measurement of Flow of Air through Registers and Grilles, by L. E. Davies (A.S.H.V.E. Transactions, Vol. 36. 1930, Vol. 37. 1931, and Vol. 39. 1933). ' ...................... 765 American Society of Heating and Ventilating Engineers Guide, 1936 in which . V = average indicated velocity obtained by the anemometer traverse. A = gross area of grille, square feet. K - coefficient determined by experiment. For average use, with exhaust grilles,. K may be taken as 0.8 for all usual velocities. This formula is of advantage, especially with ornamental grilles, in that the free area need not be measured. The flow of air through registers and grilles is of considerable impor tance, being frequently the only convenient method of measuring the volume of supply air to a room. While duct measurements, if available, are more dependable, grille measurements provide a fairly accurate method, if care is taken in the technique of using the anemometer. Kata-Thermometer The Kata-thermometer can be used to determine air velocities pro vided the walls and surrounding objects are at or near the room tem perature. Especially at low velocities it constitutes a useful instrument for readily detecting drafts. The instrument is essentially an alcohol thermometer with a bulb approximately % in. in diameter and Yi in. long with a stem 8 in. long reading from 100 F to 95 F, graduated to tenths of a degree. To take readings the bulb is heated in water until the alcohol expands and rises into a top reservoir. The time in seconds required for the liquid to fall from 100 F to 95 F is recorded with a stop watch and this time is a measure of the rate of cooling. The dry Kata loses its heat by radiation and by convection so for constant velocities the time of cooling is a function of the dry-bulb tem perature of the surrounding air. The wet Kata; which has a cloth covering fitted snugly around its bulb, loses heat by radiation, convection, and evaporation, and for constant velocities its rate of cooling is a function of the wet-bulb temperature of the air irrespective of the dry-bulb tem perature or relative humidity. It does not follow, however, that the difference in rate of cooling of the dry and the wet Kata is caused by evaporation. A change in the wet-bulb temperature produces a change in the surface temperature of the wet Kata which in turn affects the heat lost by radiation and by convection. Several precautions should be taken to bbtain the best results with this instrument: 1. To obtain velocity readings use the dry Kata since the error in timing is reduced. 2. The instrument should be heated and allowed to cool two dr three times before recording the final time of cooling. The first reading is not reliable. 3. All traces of moisture must be removed from the dry Kata before timing to eli minate error introduced by evaporation. . 4. Use only the formula applying to a particular instrument. Each Kata receives an individual calibration. HUMIDITY MEASUREMENT The sling psychrometer is the recognized standard instrument for determining humidities. In order to obtain accurate readings considerable 766 SJSJSS* Chapter 43--Test Methods and Instruments skill is required on the part of the operator. The wicking and water must be clean and the temperature of the water should be slightly above the wet-bulb temperature of the surrounding air. The psychrometer should be swung rapidly and several and frequent observations should be made to see that the wet-bulb temperature has become stationary before the final reading is noted. Care should be taken that the wet-bulb has reached a minimum temperature, but the wick must still be moist. Standard psychrometric tables should be used4. In making wet-bulb measurements below 32 F the same procedure is followed as above 32 F. The water is liquid at the start, but as the sling is operated it will freeze rapidly enough so that in quickly giving up the latent heat of fusion, the indicated wet-bulb temperature may drop below the actual wet-bulb temperature. After the liquid on the bulb has become thoroughly frozen the wet-bulb temperature will rise to normal. A very thin film of ice is more desirable than a thick film. Care must be taken to read the temperatures in the region below 32 F accurately because the spread between the wet- and dry-bulb is small. In taking humidity readings in ducts it is usually impracticable to use a sling psychrometer. For this work the stationary hygrodeik arranged for bolting on to the side of the duct, with two bulbs extending into the duct, will be found very convenient. Owing to the velocity of the air. passing over the bulbs within the duct an accurate reading will be secured, corresponding to that given by the sling psychrometer. Various forms of humidity recorders are available, some merely re cording wet- and dry-bulb temperatures, and others recording relative humidity directly. Any form of wet- and dry-bulb device must have sufficient air velocity over the thermometer bulbs to insure accurate readings; this velocity should be secured by a fan if the air is not itself in motion, as in a duct. For extremely low humidities, or for humidity measurements above 212 F, a thermal conductivity method is available6. CARBON DIOXIDE DETERMINATION6 At ordinary concentrations carbon dioxide is not harmful. The amount of carbon dioxide in the air is a convenient index of the rate of air supply, and of the distribution of the air within rooms. Unequal carbon dioxide concentrations in parts of a room indicate improper air distribution. The Petterson-Palmquist apparatus has been generally accepted as the standard device for the determination of carbon dioxide in air investiga tions. The principle involved is the measurement of a given volume of air, the absorption of the contained carbon dioxide in a caustic potash solution, and the remeasurement of the volume of air at the original pressure in a finely graduated capillary tube, the difference in volume representing the absorbed carbon dioxide. (See Report of Committee on Standard Methods for Examination of Air, American Public Health Asso ciation, Vol. 7, No. 1; American Journal of Public Health, Jan., 1917.) _ __ _______ .w* ncsuic, neiauve xrumiany arm temperatures ot the Dew .Point; U. S. Department of Agriculture, Weather Bureau, Washington, D. C. *Gas Analysis by Measurement of Thermal Conductivity, H. A. Daynes, Cambridge Press, 1933. 'Indices of Air Changes and Air Distribution, by F> C. Houghten and J. L. Blackshaw (A.S.H.V.E. Transactions, Vol. 39, 1933). 767 / American Society of Heating and Ventilating Engineers Guide, 1936 A thermal conductivity method may also be used to measure carbon dioxide in air over a range of 0 to 1.5 per cent5. Where field conditions are such that this apparatus may not be con veniently used, as in street cars, air samples may be collected in clean bottles having mercury-sealed rubber stoppers, and these may be sub jected to laboratory analysis. DUST DETERMINATION Many laboratory methods have been developed to measure the dust in the air. These involve the collection of dust on sticky plates, on filter paper, in water, on porous crucibles, or by electric precipitation, and the subsequent determination of the amount of dust by microscopic counting, weighing, or titration. While there is no standard method, the Hill dust counter, using a microscope, the impinger7, using chemical changes in water, and the Lewis sampling tube8, involving the analytical weighing of a porous crucible, are accepted. All test results should be accompanied by the name of the instrument used as great variation in.counts with the different instruments will be obtained. The American Society of Heating and Ventilating Engineers has developed a code9 for the testing and rating of air cleaning devices used in general ventilation work. FLUE GAS ANALYSIS The analysis of flue gases by chemical means is made with the Orsat apparatus. A solution of KOH is used to absorb the C02. Free oxygen is absorbed by a mixture of pyrogallic acid and KOH. The solution for absorbing . the CO is cuprous chloride. The apparatus consists of a burette surrounded by a Water jacket, to receive and measure the volume of gas. The burette is connected by a manifold of glass to pipettes con taining liquids for absorbing C02, 02 and CO. . Various forms of automatic indicating and recording gas analysis devices are available, operating on either chemical or physical principles. Such devices are convenient for plant operation. MEASUREMENT OF SMOKE DENSITY Relative smoke density is usually measured by comparison with the Ringelmann Chart (Fig. 1). In making observations of the smoke issuing from a chimney, four cards ruled like those in Fig. 1, together with a card printed in solid black and another left entirely white, are placed in- a horizontal row and hung at a point 50 ft from the observer and con veniently in line with the chimney. At this distance, the lines become invisible, and the cards appear .to be of different shades of gray, ranging from very light gray to almost black. The observer glances from the smoke coming from the chimney to the cards, which are numbered from 0 to 5, determines which card most nearly corresponds with the color of the smoke, and makes a record accordingly, noting the time. Observa- TPublic Health Bulletin, No. 144, -1925, U. S. Public Health Service. . Testing and Rating of Air Cleaning Devices Used for General Ventilation Work, by Samuel R. Lewis (A.S.H.V.E. Transactions, VoI. 39. 1933). See A.S.H.V.E. Standard Code for Testing and Rating Air Cleaning Devices Used in General Ventila tion Work (A.S.H.V.E. Transactions, Vol. 39. 1933). . '' . 768 . > 43--Chapter. Test Methods and Instruments tions are made continuously during one minute, and the estimated average density during that minute recorded. The average of all the records made during a boiler test is taken as the average figure for the smoke density during the test, and the entire record is plotted on cross-section paper in order to show how the smoke varied in density from time to time. Smoke Recorders Smoke recorders are available which give a much more accurate in dication of the amount of smoke being produced than does the Ringel mann Chart. They all depend upon projecting a beam of light through the smoke flue or through a separate compartment from which a sample of the flue gas is drawn continuously. The light of the beam which passes Fig. 1. Ringelmann Smoke Chart through without being absorbed by the smoke is measured to determine the smoke density. Most of these instruments make use of a photo electric cell or a thermopile to measure the relative amount of light which has not been absorbed. Standard electrical instruments serve for in dicating or recording. MEASUREMENT OF RATE OF HEAT TRANSMISSION The standard methods of testing built-up wall sections are by means of the guarded hot-boxw and the guarded hot-plate11. The Nicholls heat-flow meter11 may be used for testing actual walls of buildings. It would be obviously impossible to determine the air-to-air heat trans mission coefficients of every type of wall construction in use with the heat-flow meter, the guarded hot-box or the guarded hot-plate on account of the great amount of time involved. Hence, the method of computing , the coefficients from the fundamental constants must be resorted to in most cases. The guarded hot-plate is used to determine the fundamental constants. The heat-flow meter, guarded hot-box and guarded hot-plate tests can be used to good advantage in checking the accuracy of the computed values. wv*. vwv iv. itutv itnuaiuRiaiuu uuuugu wa.ua V.Ji. 1 RANSACTIONS, Vol. 34, 1928) and Report of the Committee on Heat Transmission, National Research Council. . "See Measuring Heat Transmission in Building Structures and a Heat Transmission Meter, by P. Nicholls (A.S.H.V.E. Transactions, Vol. 30. 1924). . 769 American Society of Heating and Ventilating Engineers Guide, 1936 If the hot-box or hbt-plate methods are used, tests are usually run under still air conditions, which means there is no wind movement over the surfaces of the wall during the test. In the hot-plate method of test the inside surface coefficient is eliminated by the plate's being in direct contact with the wall. In practice, some wind movement over the exterior surface of the wall should always be allowed for; hence, still-air coefficients cannot be used over the outside of the building during the heating season. Moreover, still-air transmission coefficients cannot be corrected to provide for moving-air conditions by applying a single constant factor. Computed coefficients of transmission for various types of construction are given in Chapter 5. EUPATHEOSCOPE The eupatheoscope affords a means of evaluating the combined effect of radiation and convection in a given environment in terms of a standard environment and in some terms related to human comfort. See Chapter 38. PROBLEMS Ii>T PRACTICE 1 9 What is the corrected barometric pressure of the atmosphere at 32 F when a mercurial barometer reading of 29.51 in. Hg, is determined in a room having a temperature of 91 F? Substitute in Equation 1. h = 29.51 [1 -- 0.000101 (91 -- 32)]. h = 29.33 in. Hg. 2 9 What advantages other than its sensitiveness, has the XJ-tube draft gage or manometer for measurement of low pressures? Inherent accuracy without calibration and low cost of the essential parts, which are glass tubing and an ordinary scale. 3 Are thermocouples as accurate as mercury thermometers? Within the range which can be measured with both instruments (below 1000 F) either one may be made as sensitive as the service requires. The accuracy of a thermocouple temperature measurement depends chiefly on: (1) an accurate calibration of the wire, (2) the sensitiveness of the electrical instrument, (3) accurate cold-junction control, and (4) proper placement of the sensitive junction. 4 9 When an anemometer is used for measuring- the air discharged from1 a grille or register, does it read the velocity through the gross face area or the velocity through the net free area? .. Neither. If either of these velocities is required, it should be calculated by means of Equation 2. ' 5 9 Do common errors made in humidity determination produce a result that is too high or too low? ' A higher relative humidity than the true value is likely to be found, either because there is insufficient velocity over the wet-bulb or because the reading is not taken at the right time. 6 9 What is the purpose of the carbon dioxide determination? It is an index of the adequacy of fresh air supply and also an indicator of air distribution. 770 Chapter 44 TERMINOLOGY Glossary of Physical and Heating and Ventilating Terms Used in the Text, Standard Abbreviations, Conversion Equations, Drafting Symbols, A.S.H. V.E. Codes ' Absolute Humidity: See H-umidity. Absolute Pressure: The sum, at any particular time, of the gage pressure and the atmospheric pressure. Absolute Temperature: The temperature of a substance measured above absolute zero. Absolute Zero: The temperature ( -- 459.6 F) at which the molecular motion of a substance theoretically ceases. This is the temperature at which the substance theoretically contains no heat energy. Acceleration: The rate of change of velocity. In the fps system this is expressed in units of one foot per second per second. ___ v Acceleration Due to Gravity: The rate of gain in velocity of a freely falling body. In the fps system this is 32.174 feet per second per second. Adiabatic: An adjective pertaining to or. designating variations in volume or pressure not accompanied by gain or loss of heat. When a substance undergoes adiabatic expansion, since it does not receive heat from without, the work which it does is at the expense of its internal energy,' and therefore its temperature falls; similarly, when it is adiabatically compressed its temperature rises. Adsorption: The adhesion- of the molecules of gases or dissolved sub stances to the surfaces of solid bodies, resulting in a concentration of the gas or solution at the place of contact. Air Cleaner: A device designed for the purpose of removing air-borne impurities such as dusts, fumes and smokes. (Air cleaners include air' washers and air 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 tempera ture, humidity, motion, distribution, dust, bacteria, odors, toxic gases, and ionization, most of which affect in greater or lesser degree human health or comfort. . .. - -........... Air Infiltration: The inleakage of air through cracks and crevices, and through doors, windows and other openings, caused by wind pressure or temperature difference. -. . . 771 American Society of Heating and Ventilating Engineers Guide, 1936 Air Washer: An enclosure in which air is forced through a spray of water in order to cleanse, humidify, or dehlumidify the air. Anemometer: An instrument for measuring the velocity of moving air. Atmospheric Pressure: The pressure exerted by the atmosphere in all directions, as indicated by a barometer. Standard atmospheric pressure is considered to be 14.7 lb per square inch, which is equivalent to 29.92 in. of mercury, . Baffle: A plate or wall for deflecting gases or fluids. Blast: This word was formerly used to denote forced air circulation, particularly in connection with central fan systems using steam or hot water as the heating medium. As applied in this sense, the word blast is now obsolete. Boiler: A closed vessel in which steam is generated or in which water is heated. Boiler Heating Surface: That portion of the surface of the heattransfer 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. (A.S.M.E. Power Test Codes, Series 1929.) Boiler Horsepower: The equivalent evaporation of 34.5 lb of water per hour from and at 212 F. This is equal to a heat output of 970.2 X 34.5 = 33,471.9 Btu per hour. British Thermal Unit: The mean British thermal unit *s^gQ of the heat required to raise the temperature of 1 lb of water from 32 F to 212 F. It is substantially equal to the quantity of heat required to raise 1 lb of water from 63 F to 64 F. One Btu = kwhr. By-pass: A pipe or duct, usually controlled by valve or damper, for short-circuiting fluid flow. Calorie: The mean calorie is of the heat required to raise the temperature of 1 gram of water from Zero C to 100 C. It is substantially equal to the quantity of heat required toNraise one gram of water from 14.5 C to 15.5 C. , 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 distribution ducts. See Chapters 9 and 22. Chimney Effect: The tendency in a duct or other vertical air passage for air to rise when heated, owing to its decrease in density. Coefficient of Transmission: The amount of heat (Btu) transmitted from air to air in one hour per square foot of the wall, floor, roof or ceiling for a difference in'temperature of 1 F between the air on-the inside and that on the outside of the wall, floor, roof or ceiling. 772 Chapter 44--Terminology Column Radiator: A type of direct radiator. This radiator has not been listed by manufacturers since 1926. Comfort Line: The effective temperature at which the largest per centage of adults feel comfortable. Comfort Zone {Average): The range of effective temperatures over which the majority (50 per cent or more) of adults feel comfortable. Comfort Zone (Extreme): The range of effective temperatures over which one or more adults feel comfortable: (See Chapter 3.) Concealed Radiator: See Convector. Conductance: The amount of heat (Btu) transmitted from surface to surface in one hour through one square foot of a material or construc tion, whatever its thickness, when the temperature difference is 1 F between the two surfaces. Conduction: The transmission of heat through and by means of matter unaccompanied by any obvious motion of the matter. Conductivity: The amount of heat (Btu) transmitted in one hour through one square foot of a homogeneous material 1 in. thick for a difference in temperature of 1 F between the two surfaces of the material. Conductor (heat): A material capable of readily conducting heat. The opposite of an insulator or insulation. Constant Relative Humidity Line: Any line on the psychrometric chart representing a series of conditions which may be evaluated by one percentage of relative humidity; there are also constant dry-bulb lines, wet-bulb lines, effective temperature lines, vapor pressure lines, and lines showing other physical properties of air mixed with water vapor. Control: Any manual or automatic device for the regulation of a machine to keep it at normal operation. If automatic, it is considered that the device is motivated by variations in temperature, pressure, time, light, or other influences. Convection: The transmission of heat by the circulation of a liquid or a gas such as air. Convection may be natural or forced, Convector: A concealed radiator. A heating unit and an enclosure or shield located either within, adjacent to, or exterior to the room or space to be heated, but transferring heat to the room or space mainly by the process of convection. If the heating unit is located exterior to the room or space to be heated, the heat is transferred through one or more ducts or pipes; see Chapter 30. Corrosive: Having the power to wear away or gradually change the texture or substance of a material. Decibel: The standard unit for noise or sound intensity. One decibel is equal to ten times the logarithm to the base e of the ratio of the sound intensities. Degree-Day: A unit, based upon temperature difference and time, used in specifying the nominal heating load in winter. For any one day there exist as many degree-days as there are degrees Fahrenheit dif ference in. temperature between the average outside air temperature, taken over a 24-hour period, and a temperature of 65 F. Dehumidify: To remove water vapor from the atmosphere; to , remove water vapor or moisture from any material. 773 X American Society of Heating and Ventilating Engineers Guide, 1936 Density: The weight of a unit volume, expressed in pounds per cubic foot. d = yWr. Dew-Point Temperature: The temperature corresponding to satura tion (100 per cent relative humidity) for a given moisture content. Diffuser: A vaned device placed at an air supply opening to direct the air flow. 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 Radiator: Same as radiator. Direct-Return System {Hot water): A hot water system in which the water, after it has passed through a heating unit, is returned to the boiler along a direct path so that the total distance traveled by the water is the shortest feasible, and so that there are considerable differences in the lengths of the several circuits composing the system. Down-Feed One-Pipe Riser {Steam): A pipe which carries steam downward to the heating units and into which the condensation from the heating units drains. 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 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. Draft Head {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 condensation from the steam side of a piping system to the water or return side of the system. . Dry Air: Air with which no water vapor is mixed. This term is used comparatively, since in nature there is always some water vapor included in air, and such water vapor, being a gas,-is dry. Dry-Bulb Temperature: The temperature of the air indicated by any type of thermometer not affected by the water vapor content or relative humidity of. the air. Dry Return: 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 wet return. Dust: Solid material in a finely divided state, the particles of which are large and heavy enough to fall with increasing velocity, due to gravity in still air. For instance, particles of fine sand or grit, the average diameter of which is approximately 0.01 centimeter, such as are blown on a windy day, may be called dust. Dynamic Head or Pressure: The total or impact pressure. This is the sum of the radial pressure and the velocity pressure at the point of measurement. '. Effective Temperature: An arbitrary index of the degree of warmth or cold felt by the human body in response to temperature, humidity, 774 Chapter 44--Terminology and movement of the air. Effective temperature is. a composite index which combines the readings of temperature, humidity, and air motion into a single value. The numerical value of the effective temperature scale has been fixed by the temperature of saturated air which induces an identical sensation of warmth. Enthalpy: Total heat or thermal potential. Entropy: The logarithmic probability of a state. It is the integra tion between two absolute temperatures of the quotient of the quantity of heat divided by the absolute temperature at the condition at which the temperature is taken. It is, therefore, a numeric which explains a dif ference in conditions between two points in a heat cycle. Entropy, which can vary with temperature, volume, or pressure, is constant during adiabatic expansion in a reversible cycle or during isentropic expansion in an irreversible cycle. Entropy is a function of the unavailable energy in any system. 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 atmospheric pressure. Estimated Design Load: The load, stated in Btu per hour or equiv alent direct radiation, as estimated by the purchaser for the conditions of inside and outside temperature for which the amount of installed radiation was determined. It is the sum of the heat emission of the radiation to be actually installed plus the allowance for the heat loss of the connecting piping plus the heat requirement for any apparatus requiring heat con nected with the system. (A.S.H.V.E. Standard Code for Rating Steam Heating Solid Fuel Hand-Fired Boilers--edition of April 1932.) Estimated Maximum Load: Construed to mean the load stated in Btu per hour or equivalent direct radiation that has been estimated by the purchaser to be the greatest or maximum load that the boiler will be called upon to carry. (A.S.H.V.E. Standard Code for Rating Steam Heating Solid Fuel Hand-Fired Boilers--edition of April 1932.) Extended Heating Surface: See Heating Surface. Extended Surface Heating Unit: A heating unit having a relatively large amount of extended surface which may be integral with the core containing the heating medium or assembled over such a core, making good thermal contact by pressure or by being soldered to the core or by both pressure and soldering. An extended surface heating unit is usually placed within an enclosure and therefore functions as a convector. Fan Furnace System: See Warm Air Heating System. Force: The action on a body which tends to change its relative con di.tion as to rest or motion. F = -W---V-- . Fumes: Particles of solid matter resulting from such chemical pro cesses as combustion, explosion, and distillation, ranging from 0.1 to 1.0 micron in size. > Furnace: That part of a boiler or warm air heating plant in which combustion takes place. Also, a fire-pot. ' Furnace Volume {total): The total furnace volume for horizontal- 775 American Society of Heating and Ventilating Engineers Guide, 1936 return tubular boilers and water-tube boilers is the cubical contents of the furnace between the grate and the first plane of entry into or between tubes. It therefore includes the volume behind the bridge wall as in ordinary horizontal-return tubular boiler settings, unless manifestly in effective (i.e., no gas flow taking place through it), as in the case of wasteheat 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.) . Gage Pressure: Pressure measured from atmospheric pressure as a base. Gage pressure may be indicated by a manometer which has one leg connected to the pressure source and the other exposed to atmospheric pressure. Grate Area: The area of the grate surface, measured in square feet, to be used in estimating the rate of burning fuel. This area is construed to mean the area measured in the plane of the top surface of the grate, except that with special 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 defined above. (A.S.H.V.E. Standard and Short Form Heat Balance Codes for Testing Low-Pressure Steam Heating Solid Fuel Boilers.) Gravity Warm Air Heating System: See Warm Air Heating System. Grille: A perforated covering for an air inlet or outlet usually made of wire screen, pressed steel, cast-iron or plaster. Grilles may be plain or ornamental. Heat: A form of energy generated by the transformation of some other form of energy, as by combustion, chemical action, or friction. Accord ing to the molecular theory, heat consists of the kinetic and potential energy of the molecules of a substance. The addition of heat energy to a body increases the temperature or the kinetic energy of motion of its molecules (sensible heat) or increases their potential energy of position but does not increase the temperature, as when melting or boiling occurs {latent heat). .N Heat Capacity: The amount of heat (Btu or calories) required to raise the temperature of a body of any mass and variety of parts one degree (Fahrenheit or centigrade). This will depend on the masses and specific heats of the various parts of the body. ' Therefore 5 = fi ii + : + mj j|. . . . etc. where S is the heat capacity and mi, m, ii, and si, St, s't stand for the masses and cor responding specific heats of the parts, respectively. Heating Medium: A substance such as water, steam, air., electricity 776 Chapter 44--Terminology 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. Heating Surface: The exterior surface of a heating unit. Extended heating surface {or extended surface): Heating surface having air on both sides and heated 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.) Heat of the Liquid: The sensible heat of a mass of liquid above an arbitrary zero. Horsepower: A unit to indicate the time rate of doing work equal to 550 ft-lb per second or 33,000 ft-lb per minute. (One horsepower = 745.8 watts. In practice this is considered 746 watts.) . Hot Water Heating System: A heating system in which water is used as the medium by which heat is carried through pipes from the boiler to the heating units. Humidify: To add water vapor to the atmosphere; to add water vapor or moisture to any material. Humidity: Thewater vapor mixed with dry air in the atmosphere. Ab solute humidity refers to the weight of water vapor per unit volume of space occupied, expressed in grains or pounds per cubic foot. Specific humidity refers to the weight of water vapor in pounds carried by one pound of dry air. Relative humidity is a ratio, usually expressed in per cent, used to indicate the degree of saturation existing in any given space resulting from the water vapor present in that space. Relative humidity is either the ratio of the actual partial pressure of the water vapor in the air to the saturation pressure at the dry-bulb temperature, or the ratio of the actual density of the vapor to the density of saturated vapor at the dry-bulb temperature. The presence of air or other gases in the same space at the same time has nothing to do with the relative humidity of the space. Humidistat: A regulatory device, actuated by changes in humidity, used for the control of humidity. Hygrostat: Same as humidistat. , . Inch of Water: A measure of pressure which refers to the difference in the heights of the legs of a water filled manometer. Insulation {heat): A material having a relatively high heat-resistance per unit of thickness. . Isobaric: An adjective used to indicate a change taking place at con stant pressure. Isothermal: An adjective used to indicate a change taking place at constant temperature. Latent Heat: See Heat. Laws of Thermodynamics: The first law states that the total energy of an isolated system remains constant and cannot be increased of dimini shed by any physical process whatever. The second law states that no change in a system of bodies that takes place of itself can increase the available energy of a system. Manometer: An instrument for measuring pressures; essentially a U-tube partially filled with a liquid, usually water, mercury,. or a light 777 American Society of Heating and Ventilating Engineers Guide, 1936 oil, so the amount of displacement of the liquid indicates the pressure being exerted on the instrument. Mass: The quantity of matter, in pounds, to which the unit of force (one pound) will give an acceleration of one foot per second per second.. W m = --. g . Mb, Mbh1; Symbols which represent, respectively, 1000 Btu and 1000 Btu per hour. Mechanical Equivalent of Heat: The mechanical energy necessary to produce 1 Btu of heat energy. J -- 777.5 ft-lb. Micron: A unit of length, the thousandth part of one millimeter or the millionth of a meter. Mol: The unit of weight for gases. It is defined as m lb where m denotes the molecular weight of a gas. For any gas the volume of 1 mol at 32 F and standard atmospheric pressure is 358.65 cu ft and the weight of a cubic foot is 0.002788 m lb. Neutral Zone: The level within a room or building at which the pressure is exactly equal to the outside barometric pressure. One-Pipe Supply Riser {steam): A pipe which carries steam upward to a heating unit and which also carries the condensation from the heating unit in a direction opposite to the steam flow. One-Pipe System {hot water): A hot water system in which the water flows through more than one heating unit before it returns to the boiler; consequently, the heating units farthest from the boiler are supplied with cooler water than those near the boiler in the same circuit. One-Pipe System {steam): A steam heating system consisting of a main circuit in which the steam and condensate flow in the same pipe, usually in opposite directions. 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. Overhead System: Any steam or hot water system in which the supply main is above the heating units. With a steam system the return must be below the heating units; with a water system, the return'may be above the heating units. Panel Radiator: A heating unit placed on or flush with a flat wall surface and intended to function essentially as a radiator. Panel Warming: A method of heating involving the installation of the heating units (pipe coils) within the wall, floor or ceiling of the room, so that the heating process takes place.mainly by radiation from.the wall, floor or ceiling surfaces to the objects in the room. . Plenum Chamber: An air compartment maintained under pressure and connected to one or more distributing ducts. . Potentiometer: An instrument for measuring or comparing small electromotive forces. Power: The rate of performing work, expressed in units of horse power, one of which is equal to 550 ft-lb of work per second, or 33,000 ft-lb per minute. xThese symbols were approved by the A.S.H.V.E., June. 1933. 778 Chapter 44--Terminology Prime Surface: See Heating Surface. ' Psychrometer: An instrument for ascertaining the humidity or hygrometric state of the atmosphere. Psychrometric: Pertaining to psychrometry or the state of the atmosphere as to moisture. Psychrometry: The branch of physics that treats of the measurement of degree of moisture, especially the moisture mixed with the air. Pyrometer: An instrument for measuring high temperatures. Radiation: The transmission of heat through space by wave motion. Radiator: A heating unit exposed to view within the room or space to be heated. A radiator transfers heat by radiation to objects "it can see" and by conduction to the surrounding air which in turn is circulated by natural convection; a so-called radiator is also a convector but the single term radiator has been established by long usage. Concealed Radiator: See Convector. Recessed Radiator: A heating unit set back into a wall recess but not enclosed. Refrigerant: A substance which produces a refrigerating effect by its absorption of heat while expanding or vaporizing. Register: A grille with a built-in multiblade damper or shutter. Relative Humidity: See Humidity: see also discussion of relative humidity in Chapter-1. Return Mains: The pipes which return the heating medium from the heating units to the source of heat supply. Reversed-Retum System {hot water): A hot water heating system in which the water from seyeral heating units is returned along paths arranged so that all circuits composing the system or composing a major subdivision of the system are practically of equal length. Roof Ventilator: A device placed on the'roof of a building to permit egress of air. . . Saturated Air: Air containing as much water vapor as it can hold without any condensing out; in saturated air, the partial pressure of the water vapor is equal to the vapor pressure of water at the existing tem perature. . Sensible Heat: See Heat. Smoke: 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. Specific Gravity: The ratio of the weight of a body to the weight of an equal volume of water at some standard temperature, usually 39.2 F. Specific Heat: The quantity of heat, expressed in Btu, required to raise the temperature of 1 lb of a substance IF. Specific Volume: The volume, expressed in cu ft, of one pound of a substance, v = -4- = =7. d .W 779 i American Society of Heating and Ventilating Engineers Guide, 1936 Split System: A system in which the heating and ventilating are accomplished by means of radiators or convectors supplemented by mechanical circulation of air (heated or unheated) from a central point. Square Foot of Heating Surface (equivalent): Equivalent direct radiation (EDR). By definition, that amount of heating surface which will give off 240 Btu per hour. The equivalent square feet of heating surface may have no direct relation to the actual surface area. Stack Height: The height of a gravity convector between the bottom of the heating unit and the top of the outlet opening. Standard Air: As defined by A.S.H.V.E. codes, standard air is air weighing 0.07488 lb per cubic foot, which is air at 68 F dry-bulb and 50 per cent relative humidity with a barometric pressure of 29.92 in. of mercury. (Most engineering tables and formulae involving the weight of air are based on air weighing 0.07495 lb per cubic foot, which is dry air at 70 F dry-bulb with a barometric pressure of 29.92 in. of mercury. The error involved in disregarding the difference between the above two weights is very slight and in most instances may be neglected.) Static Pressure: The compressive pressure existing in a fluid. It is a measure of the potential energy of the fluid. Steam: Steam is water vapor which exists in the vaporous condition because sufficient heat has been added to the water to supply the latent-. heat of evaporation and change the liquid into vapor. Steam in contact . with the water from which it has been generated may be dry saturated steam or wet saturated steam. The latter contains more or less actual water in the form of mist. If steam is heated, and the pressure main tained the same as when it was vaporized, its temperature will increase and it will become superheated. Steam Heating System: A heating system in which heat is trans ferred from the boiler dr other source of steam to the heating units by means of steam at, above, or below atmospheric pressure. Steam Trap: A device for allowing the passage of condensate and preventing the passage of steam, or for allowing the passage of air as well as condensate.. . Superheated Steam: See Steam. Supply Mains {steam): The pipes through which the steam flows from the boiler or source of supply to the run-outs and risers leading to the heating units. .\ . . Surface Conductance: The amount of heat (Btu) transmitted by radiation, conduction, and convection from a surface to the air or liquid surrounding it, or vice versa, in one hour per square foot of the sui;face for a difference in temperature of 1 deg between the surface and the sur rounding air or liquid. '- Synthetic Air Chart: A chart for evaluating the air conditions maintained in a room. / Therm: Symbol used in the gas industry representing 100,000 Btu. Thermal Resistance: The reciprocal of conductance. ' Thermal Resistivity: The reciprocal of conductivity. . . Thermodynamics: The science which treats of the mechanical actions or relations of heat. . 780 Chapter 44--Terminology Thermostat: An instrument which responds to changes in tempera ture and which directly or indirectly controls the source of heat supply. Ton of Refrigeration: The extraction of 12,000 Btu per hour. Ton Day of Refrigeration: The heat removed by a ton of refriger ation operating for one day; 288,000 Btu. Total Heat: A thermodynamic quantity, variously called heat con tent, thermal potential, enthalpy. It is the heat required per unit mass (Btu per lb) to raise a given substance to a given point from an arbitrary datum point. It is the sum of the heat of the liquid, the latent heat, and any miscellaneous heat which may be present. Total Pressure: The sum of the static and velocity pressures in a fluid. It is a measure of the total energy of the fluid. Tube (or Tubular) Radiator: A cast-iron heating unit used as a radiator and having small vertical tubes. . Two-Pipe System (steam or water): A heating system in which one pipe is used for the supply of the heating medium to the heating unit and another for the return of the heating medium to the source of heat supply. The essential feature of a two-pipe system is that each heating unit receives a direct supply of the heating medium which medium cannot have served a preceding heating unit. Underfeed Distribution System . {hot water): A hot water heating system in which the main flow pipe is below the heating units. Underfeed Stoker: A stoker which feeds the coal underneath the fuel . bed. Unit Air Conditioner: A piece of equipment designed to provide simutaneous control of at least four of the seven functions (page 237) involved in summer and winter air conditioning. The apparatus is com pactly housed in a cabinet placed within' or immediately adjacent to the rooms served. The parts comprising a unit air conditioner are assembled at the point of manufacture, and the performance of the assembly is the responsibility of the manufacturer. See Chapter 12. . Unit Cooler: A cooling device, usually comprising an extended- surface element and a motor-driven fan mounted integrally in a housing, located within or adjacent to the room served. Generally no ducts are attached to inlet or outlet. The refrigerant is brought to the unit from an outside source, and the fan drives air over the cooling element. ' Unit Heater: A heating device, usually comprising an extendedsurface element or a gas burner, mounted with a motor-driven fan in a housing, located within or adjacent to the room served. Generally, no ducts are attached to inlet or outlet. The fluid for heating is brought to the unit from- an outside source, and the fan drives air over the heating element. Unit heaters are used primarily in industrial applications. . Unit Ventilating-Heater: A ventilating and heating device com prising a motor-driven fan, an extended-surface heating element and usually a filter, mounted in a housing, located within or adjacent to the. room served.! Outdoor air is obtained through a dampered direct con nection or a short duct from a nearby wall or window opening. Provision 781 of andAmerican Society Heating Ventilating Engineers Guide, 1936 for partial recirculation is usually made. If a humidifier is included, such a filter-equipped device becomes a winter-type unit conditioner. Unit ventilators are used primarily for offices, schools, and places of public assembly. Up-Feed System {steam): A steam 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 equip ped with the necessary accessory apparatus which will permit operating the system below atmospheric pressure when desired. Vapor: Any substance in the gaseous state. . Vapor Heating System: A steam heating system which operates under pressures at or near atmospheric and which returns the condensa tion to the boiler or receiver by gravity. Vapor systems have thermo static traps or other means of resistance on the return ends of the heating units for preventing steam from entering the return mains; they also have a pressure-equalizing and air-eliminating device at the end of the dry return. Direct Vent Vapor System: A vapor heating system with air valves which do not permit re-entry of air. Vapor Pressure: The equilibrium pressure exerted by a vapor in contact with its liquid. Velocity: The time rate of motion of a body in a fixed direction. In - s- the fps system it is expressed in units of one foot per second. V = Velocity Pressure: The pressure corresponding to the velocity of flow. It is a measure of the kinetic energy of the fluid. Ventilation: The process of supplying or removing air by natural or mechanical means, to or from any space. Such air may or may not have been conditioned. (See Air Conditioning.) ' 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 the various rooms of the building through ducts. If the motive head producing flow depends on the difference in weight between the heated air leaving the casing and the cooler air entering the bottom of the casing, it is termed a gravity system. A booster fan may, however, be used in conjunction with a gravity-designed system. If a fan is used to produce circulation and the system is designed especially for fan circulation, it is termed a fan furnace system or a centralfanfurnace system. A fan furnace system may include air washers and filters. Wet-Bulb Temperature: The lowest temperature which a water wetted body will attain when exposed to an air current. This is the temperature of adiabatic saturation. ' Wet Return: 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 Dry Return. 782 Chapter 44--Terminology ABBREVIATIONS2 Absolute................................................................................................................................. abs Acceleration, due to gravity...................... g Acceleration, linear..... ...................... :.............................................................................. ...... a Air horsepower........................ ........................................................................................ air hp Alternating-current (as adjective)............................................ i_....................................... a-c Ampere.................................................. -............................................................................ amp Ampere-hour.-................................................................................................................ amp-hr Area................................................... -..................................... ............. .............................. --A Atmosphere...... .......................................................... atm Average............................................................................. -........... -................................... -avg Avoirdupois............................................................................ avdp Barometer...................................................................... bar. Boiler pressure....................................................................... -.............................. -............. ibp ' Boiling point..................................................-.......................... -.......................................... bp Brake horsepower................................................................................................ bhp Brake horsepower-hour.......................................... .bhp-hr British thermal unit............................................................................................................. Btu Calorie....................................................................................................................................cal Centigram............................................ eg Centimeter............................................................................................................................. cm Centimeter-gram-second (system)......... ~-- ....................................................................cgs Change in specific volume during vaporization...........................................-.................... rfg Cubic................................................ ............ .......................................-........................ -.......cu Cubic foot............. ...................................................,..........................................................cu ft Cubic feet per minute..........................................................................................................cfm Cubic feet per second.......................................................................... .cfs Decibel........... db Degree2...........................................................................................................................deg or Degree centigrade-...........................................;......................................................................C Degree Fahrenheit--.................................................................................................................F Degree Kelvin-............................................................ J..........................................................K Degree R&aumur......................................................... R Density, Weight per unit volume. Specific weight.!-..........................................d or p (rho) Diameter....................................................................................................................D or diam Direct-current (as adjective)......... .................... d-c Distance, linear--............................ s Dry saturated vapor. Dry saturated gas at saturation pressure and temperature, Vapor in contact with liquid_______________________________ _________Subscript g Entropy (The capital should be used for any weight, and the small letter for unit weight.)-........................................................................ ...................................... .... S or s Feet per minute....................................................................................................................fpm Feet per second......................................................................................................................fps Foot.......... .................................................................................................................................ft Foot-pound............................................................................................................... ft-lb Foot-pound-second (system)............... fps Force, total load............................................................ 1.................. .................................. ... F Freezing point............................................................... :.........................................................fp Gallon......................................... ..gal Gallons per minute......-........ .......... ........... ....... :................. .............................................gpm Gallons per second.....................................l.................................. ...................................... gps Gram......................................................... :.....:...................... :........ J................................. ...... g Gram-calorie......................................................... -g-cal 5From compilations of abbreviations approved by the American Standards Association, X, 10 a, c, f, and i. As a general rule the period is omitted in all abbreviations except where the omission results in the formation of an English word. - It is recommended that the abbreviation for the temperature scale.F, C, K, be included.in expressions for numerical temperatures but, wherever feasible, the abbreviation for degree be omitted; as 68 F. 783 American Society of Heating and Ventilating Engineers Guide, 1936 Head............... ................ ....................................................................... -................ .......H or h 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---------------------------- ----------hf Heat content of dry saturated vapor, Total heat of dry saturated vapor, Enthalpy of dry saturated vapor..... --............................................. i.......................................... he Heat of vaporization at constant pressure................................................................ L or ftfg Horsepower.......................................................................................................... hp Horsepower-hour................... :......... ...................................................... ........................ hp-hr Inch......... ...... v._in. Inch-pound................... in-lb Indicated horsepower............................................................................................................ihp Indicated horsepower-hour................... ............ .... ...............................-.....................ihp-hr . Internal energy, Intrinsic energy. (The capital should be used for any weight and the small letter for unit weight.)............................................................................U or u Kilogram...... ........................................................................ kg Kilowatt...................................................................... ...............................-.......................... kw Kilowatthour..... ............................................................ :.............. -............................ ...kwhr Length of path of heat flow, thickness.. .............................................................................L Load, totaL__.................................... W Massi...................................................... .................. - ........................................... m Mechanical efficiency.:............................ m- Mechanical equivalent of heat-- ............................. J Melting point....... .............................................. ...................-......................................... ..mp Meter............................ ............................ ....................................................... :................... m Micron........................................................................ ....................:........................... U- (mu) Miles per hour...................... mph Minute. .......................................................................................................................:--min Molecular weight............................ .......................................... ...................................mol. wt Mol........... .......................................................... .............................. '.......................... -..... mol Ounce..................................................... ....................................... ............. :.......................... oz 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............................................ * Revolutions per minute........................... ....... :_________________ -------------------------rpm Saturated liquid at saturation pressure and temperature, Liquid in contact with vapor.......................................................................................... ............. Subscript f Specific gravity..................................................................................................................sp gr Specific neat...... .:...................................... .-........................... .--................................ sp ht or c Specific heat at constant pressure..................................... --..'................................... ....... --cp Specific heat at constant volume............................... ....... ........ ............... ................... ---cv Specific volume, Volume per unit weight, Volume per unit mass...................................... v Square foot................... .......... .................... 1.......... ----:................ .................. ,...... ........ sq ft Square inch__ ........ ..................... ............ ................................... :------------ ---------.... ;~sq in. Temperature (ordinary) F or C. (Theta is used preferably only when t is used for Time in the same discussion.).--.................................:---- -.----------- -------- t or 6 (theta) Temperature (absolute) F abs or K. (Capital theta is used preferably only when small theta is used for ordinary temperature.)_______________ T or 0 (capital theta) Thermal conductance4 (heat transferred per unit time per degree)------ ,--i.................... C CR kA L II -- h Thermal conductance per unit area, Unit conductance (heat transferred per unit time per unit area per degree) ......................................................................Ca c. =4 1 q k ' RA A(li -- /*) ~ `Terms ending iviiy designate properties independent of .size or. shape, sometimes called specific proper ties. Examples are--conductivity and resistivity. Terms ending once designate quantities depending not only on the material, but also upon size and shape, sometimes called total quantities. Examples are-- conductance and transmittance. Terms ending ion designate rate of heat transfer. Examples are--con duction and transmission. ' . ' ........... ' ' '. -* ' 784 '. Chapter 44--Terminology Thermal conductivity (heat transferred per unit time per unit area, and per degree per unit length)........ ,....................................... ............ ............................ k k = __ --___ (h - h) l : Surface coefficient of heat transfer, Film coefficient of heat transfer. Individual coefficient of heat transfer (heat transferred per unit time per unit area per degree)................................... ..................... .......................... .................................-- / g A__ / = <1 -- ti (In general / is not equal to k/L, where L is the actual thickness of the fluid film.) Over-all coefficient of heat transfer, Thermal transmittance per unit area (heat transferred per unit time per unit area per degree over-all).....................................U g_ A V = <i - /, Thermal transmission (heat transferred per unit time)............................................ j........ g Thermal resistance (degrees per unit of heat transferred per unit time).........................R Thermal resistivity.............................................. '............... ............................ .................... l/k - Vaporization values at constant pressure, Differences between values for saturated vapor and saturated liquid at the same pressure.........................................Subscript fg Velocity............ :____________ 1... ......................... ...... ................. ................. ........ :.... ...... .. V Volume (total).................... _........................................ '.......................... ............ ................... V Volume per unit time, Rate at which quantity of material passes through a machine, Quantity of heat per unit time, Quantity of heat per unit weight....... . ..q Watt............................................................ :................. ................. ............. ........................... w Watthour............... :............. ...............................................................................................whr Weight of a major item, Total weight............................................ ........ .................. ........ W Weight rate, Weight per unit of power, Weight per unit of time.................................... w Work (total)....... ,C....______________________ ______________________ ..W CONVERSION EQUATIONS Fahrenheit degrees = 9/5 (centigrade degrees + 32). Centigrade degrees = 5/9 (Fahrenheit degrees -- 32). Absolute temperature, expressed in Fahrenheit degrees . = Fahrenheit degrees + 459.6. In heating and ventilating work, 460 is usually used. Absolute temperature, expressed in centigrade degrees = centigrade degrees + 273.1. Power, Heat, and Worf 1 ton refrigeration * Latent heat of ice ' ' = IBtU pef-h,Ur \200 Btu per minute . _ = 143.33 Btu per pound . American Society of Heating and Ventilating Engineers Guide, 1936 1 Btu 1 watthour 1 mean calorie 1 kilowatt (1000 watts) 1 horsepower 1 boiler horsepower 777.6 ft-lb = ( 0.293 watthours . 252.02 mean calories ( 2,655.2 ft-lb . I 3.415 Btu I 3600 joules I 860.648 mean calories 0.003968 Btu 3.085 ft-lb 0.0011619 watthours 1.3405 horsepower 56.92 Btu per minute 44,252.7 ft-lb per minute 0.746 kilowatt 42.44 Btu per minute 33,000 ft-lb per minute 550 ft-lb per second 33,471.9 Btu per hour Weight and Volume 1 gal (U. S.) 1 British or Imperial gallon I cu ft 1 cu ft water at 60 F 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 1 long ton Pressure 1 lb per square inch 1 oz per square inch 1 atmosphere 1 in. water at. 62 F 1 ft water at 62 F 1 in. mercury at 62 F _ / 231 cu in. " \ 0.13368 cu ft = 277.274 cu in. / 7.4805 gal " i 1728 cu in. = 62.37 lb = 59.76 lb = 8.34 lb = 7.99 lb _ / 16 02 \ 7000 grains = 1.244 cu ft = 20001b = 22401b 144 lb per square foot ' 12.0416 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 1.732 in. water at 62 F F 14.7 lb per square inch 2116.3 lb per square foot 33.974 ft water at 62 F 30 in. mercury at 62 F 29.921 in. mercury at 32 F 0.03609 lb per square inch - 0.5774 02 per square inch 5.196 lb per square foot -{ 0.433 lb per.square- inch 62.355 lb per square foot - 0.491 lb per square inch 7.86 02 per square inch 1.131 ft water at 62 F 13.57 i. water at 62 F 786 Chapter 44--Terminology ' 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 1 metric ton 1 gram 1 kilometer per hour ' ._ 1 gram per square centimeter 1 kg per square centimeter (metric atmosphere) 1 gram per cubic centimeter 1 dyne 1 joule 1 metric horsepower 1 kilogram-calorie (laige calorie) = 0.3937 in. = 2.54 cm = 3.281 ft = 0.3048 m = 0.155 sq in. = 6.45 sq cm = 10.765 sq ft = 0.0929 sq m = 0.061 cu in. = 16.39 cu cm = 35.32 cu ft = 0.0283 cu m = 1000 cu cm = 0.264 gal = 2.2046 lb = 0.4536 kg = 2205 lb (avdp) = 980.59 dynes = 0.002205 lb = 0.6214 mph _ f 0.0290 in. mercury, at 0 deg C \ 0.394 in. water, at 15 C = 14.22 lb per square inch = f 0.03614 lb per cubic inch \ 62.43 lb per cubic foot = 0.00007233 poundals _ / 10,000,000 ergs ~ \ 0.73767 ft-lb . (75 kg-m per second \ 0.986 hp (U. S.) . ( 1000 gram-calories (small calorie) 1 kilogram-calorie per kilogram 3.97 Btu 1 gram-calorie per square centimeter = 1.8 Btu per pound 1 gram-calorie per square centimeter per centi = 3.687 Btu per square foot meter " = J1.451 Btu per square foot perinch 1 gram-calorie per second per square centimeter for a temperature graduation of 1 deg C per centimeter (2903 Btu per hour per square foot for a temperature graduation of 1 deg F per inch of thickness. SYMBOLS FOR HEATING AND VENTILATING DRAWINGS5 1. The objects of this standard set of symbols are to insure the correct interpretation of drawings and to conserve drafting room time by establishing simple and unmistakable symbols for the component parts of the heating and ventilating systems. In preparing the list of symbols an effort has been made to follow existing practice in so far as possible but the list cannot be expected to match exactly the easting practice of every drafting room. , 2. Simplicityease of execution and unmistakable identification were carefully con sidered in selecting the symbols. Uncommon fittings and appliances such as vacuum pumps, separators, etc., have purposely been omitted in order to produce a list which can be easily remembered. It is assumed that when the scale of the drawing permits, the valves and fittings will be drawn to scale and a conventional representation is then unnecessary. `From A.S.H.V.E. Code of Minimum Requirements for the Heating and Ventilation of Buildings, edition of 1929. 787 ofAmerican Society Heating and Ventilating Engineers Guide, 1936 3. High pressure steam supply pipe 4. Low pressure steam supply pipe 5. Hot water pipe--flow " ----------------- 6. Return pipe--steam or water 7. Air vent line 8. Flanges . 9. Screwed union 10. Elbow Hit-- A- 11. Elbow--looking up ' Of 12. Elbow--looking down 13. Tee 14. Tee--looking up 15. Tee--looking down 16. Gate valve -- 4- . -<OiH*- 4 17. Globe valve 18. Angle valve . '. 19. Angle valve--stem perpendicular 20. Lock shield valve 21. Check valve 22. Reducing valve . ,\ 23. Diaphragm valve 788 .4 IXID H<j)l-- a: 2 77tZ- 44Chapter --Terminology 24. Diaphragm valve--stem perpendicular 25. Thermostat 26. Radiator trap--elevation 27. Radiator trap--plan 28. Expansion joint 29. Column radiator--plan 30. Column radiator--elevation 31. Wall radiator--plan 32. Wall radiator--elevation 33. Pipe coil--plan 34. Pipe coil--elevation 35: Indirect radiator--plan . 36. Indirect radiator--elevation 37. Supply duct--section 38. Exhaust duct--section 39. Butterfly damper--plan (or elevation) 40. Butterfly damper--elevation (or plan) 41. Deflecting damper--square pipe ' . 42. Vanes , 43. Air supply outlet ' 44. Exhaust outlet . . . 789 Of -9 H0 PJ fl (ZZ1 0 5 cr-t) Q 0 * American Society of Heating and Ventilating Engineers Guide, 1936 A.S.H.V.E. CODES The following codes and standards relating to the design, installation, testing, rating, and maintenance of materials and equipment used for the heating and ventilation of buildings, have been adopted by the American Society of Heating and Ventilating Engineers : Subject Air Cleaning Devices Title A.S.H.V.E. Standard Code for Testing and Rating Air Clean ing Devices Used in General Ventilation Work When Adopted June, 1933 Reference A.S.H.V.E. Transactions, Vol. 39, 1933 Air Purity Synthetic Air Chart June, 1917 A.S.H.V.E. Transactions, Vol. 23, p. 607, and The Guide, 1931 Boilers (testing) Boilers (testing) Boilers-- Oil Fuel (testing) Boilers (rating) Concealed Gravity Type Radiation Standard and Short-Form Heat Balance Codes for Testing Low Pressure Steam Heating Solid Fuel Boilers (Codes 1 and 2) A.S.H.V.E. Performance Test Code for Steam Heating Solid Fuel Boilers (Code 3)a A.S.H.V.E. Standard Code for Testing Steam Heating Boilers Burning Oil Fuel A.S.H.V.E. Standard Code for Rating Steam Heating Solid Fuel Hand Fired Boilers A.S.H.V.E. Standard Code for Testing and Rating Concealed Gravity Type Radiation (Hot Water Section) June, 1929 June, 1929 June, 1932 January, 1929 Revised April, 1930 June, 1933 A.S.H.V.E. Transactions, Vol. 35, 1929 A.S.H.V.E. Transactions, Vol. 35, 1929 A.S.H.V.E. Transactions, Vol. 37, 1931 A.S.H.V.E. Transactions, Vol. 36,. 1930; p. 42 A.S.H.V.E. Transactions, Vol. 39, 1933 Convectors Ethics Fans A.S.H.V.E. Standard Code for Testing and Rating Concealed Gravity Type Radiation (Steam Code) Code of Ethics for Engineers Standard Test Code for Disc and Propeller Fans, Centrifugal Fans and Blowers January, 1931 January, 1922 May,1923. Revised June, 1931 A.S.H.V.E. Transactions, Vol. 37, .1931, p. 367 A.S.H.V.E. ' Transactions, Vol. 28, 1922, p. 6 (See frontispiece The Guide, 1936) .A.S.H.V.E. Transactions, Vol. 29, 1923, , p. 407b - Garages Code for Heating and Ven tilating Garages June, 1929 Revised . January, 1935 .A.S.H.V.E. Trans actions, Vol. 35, 1929, p. 355 A.S.H.V.E. Reprint Originally adopted by the National Boiler and Radiator Manufacturers Association. bAlso, see Heating, Piping and Air Conditioning, August, 1931, P- 743. 790. Chapter 44--Terminology Subject. Title Heat Transmission Through Walls Standard Test Code for Heat Transmission through Walls When Adopted January, 1927 Reference A.S.H.V.E. Transactions, Vol. 34, 1928, p. 253 Minimum Requirements Code of Minimum Require ments for Heating and Ventila tion of Buildings, Edition-1929 Pitot Tube Code for Use of Pitot Tube June, 1925 / January, 1914 A.S.H.V.E. Codes A.S.H.V.E. Transactions, Vol. 20, 1914, p. 211 Radiators Code for Testing Radiators January, 1927 A.S.H.V.E. Transactions, Vol. 33, 1927, p. 18 Unit Heaters Standard Code for Testing and Rating Steam Unit Heaters0 January, 1930 A.S.H.V.E. Transactions, Vol. 36, 1930, p. 165 Unit Ventilators A.S.H.V.E. Standard Code for Testing and Rating Steam Unit Ventilators June, 1932 A.S.H.V.E. Transactions. Vol. 38, 1932, p. 25 Vacuum Heating Pumps A.S.H.V.E. Standard Code for Testing and Rating Return Line Low Vacuum Heating Pumps June, 1934 A.S.H.V.E. Transactions, Vol. 40, 1934 Ventilation Report of Committee on Ventilation Standards August, 1932 A.S.H.V.E. Transactions, Vol. 38,1932, p. 383 - The following Codes and Standards have been endorsed or approved by the American Society of Heating and Ventilating Engineers : Subject Chimneys Piping Systems Warm Air Furnaces Title Sponsored bt Reference Standard Ordinance for Chim National Board of .Chapter 14, ney Construction .. Fire Underwriters The Guide, 1931 Identification of Piping Systems* American Society Heating, Piping and of Mechanical Air Conditioning, Engineers July, 1929 Standard Code Regulating the Installation of Gravity Warm Air Furnaces in Residences National Warm Air Heating and Air Conditioning Association National Warm Air Heating and Air Con ditioningA ssociation, Columbus, Ohio 'Adopted jointly by the Industrial Unit Heater Association, and the A.S.H.V.E. ,, ^Adopted November, 192S. Sponsored by (1) American Society of Mechanical Engineers, (2) National Safety Courted. . 791 w \ Catalog Data Section (Pages 793-1060) with an INDEX TO MODERN EQUIPMENT (Pages 1061-1080) . and INDEX TO ADVERTISERS (Pages 795-798) . INDEX TO ADVERTISERS American Society of Heating and Ventilating Engineers Guide, 1936 Page Aeriet Air Conditioner Company, 210 S. Clark St., Chicago, III............ ,.............. .... 799 Aerofin Corporation, 850 Frelinghuysen Ave., Newark, N. J_______ _________ 915-917 Agasote Millboard Co., The, Trenton, N. J................................................................. 939 Air Controls, Inc., 1937 West 114th St., Cleveland, Ohio--......................................... -834 Airtemp Incorporated, 8021 Conant Ave., Detroit, Mich.......................................... .. 800 Alfol Insulation Company, Incorporated, Chrysler Bldg., New York, N. Y...... 942-943 American Air Filter Co., Inc., First St. and Central Ave., Louisville, Ky......... 850-851 American Artisan (a pub.), 6 N. Michigan Ave., Chicago, 111-- ............................... 982 American Blower Corporation, Detroit, Mich....................................................... 802-803 American Brass Company, The, Waterbury, Conn............................................... 972-973 American District Steam Company, North Tonawanda, N. Y................................... 897 American Machine and Metals Manufacturing Corp., DeBothezat Division, 100 Sixth Ave., New York, N. Y......................................................... .......... ......... 899 American Moistening Company, Providence, R. 1........................................................ 822 American Radiator Company, 40 West 40th St., New York, N. Y............ 801, 861-865 American Society of Refrigerating Engineers, 37 West 39th St., New York, N. Y._ 981 American Steam Pump Company, Battle Creek, Mich................................................ 991 Anderson Manufacturing Co., Cambridge, Mass............................................... 1054--1055 Aquatic Chemical & Metallurgical Engineers, 118 East 28th St., New York, N. Y___ 860 Armstrong Cork Products Company, Lancaster, Pa..................................................... 940 Armstrong Machine Works, 851 Maple St., Three Rivers, Mich.................... 1008-1009 Auer Register Co., The, 3608 Payne Ave., Cleveland, Ohio........................ ............ 1001 Automatic Heat and Air Conditioning (a pub.), 1900 Prairie Ave., Chicago, 111........... 984 Babcock & Wilcox Company, The, 85 Liberty St., New York, N. Y......................... 877 E. B. Badger & Sons Co., 63-75 Pitts St., Boston, Mass............................................. 898 Baker Ice Machine Co., Inc., 1523 Evans St., Omaha, Nebr...................................... 823 Baldor Electric Co., 4370 Duncan Ave., St. Louis, Mo............................................. .. 966 Barber-Colman Company, Rockford, 111_______________________ _________ 1034--1035 Barnes & Jones, Incorporated, 129 Brookside Ave., Jamaica Plain, Boston, Mass..... 1014 Bayley Blower Company, 1817 S. Sixty-Sixth St., Milwaukee, Wis........ .................. 900 Beaton & Cadwell Mfg. Company, The, New Britain, Conn.... ...................... 1010-1011 Bell and Gossett Company, 3000 Wallace St., Chicago, 111................................. 924r-925 Betz Unit Air Cooler Co., Kansas City, Mo........ ......................................................... 804 Bigelow Company, The, New Haven, Conn.................................................................. 878 Bristol Company, The, Waterbury, Conn.... .......................................................... ...... 929 Brown Instrument Division, Minneapolis-Honeywell Regulator Co., Philadelphia, Buckeye Blower Company, State Rd. and Rhawn St., Holmesburg, Philadelphia, Buffalo Forge Company, 484 Broadway, Buffalo, N. Y............................................. _ 901 Builders Iron Foundry, 23 Codding St., Providence, R. 1............................................ 965 Burnham Boiler Corporation, Irvington-on-Hudson, N. Y........... ...................... 866-867 Burt Mfg. Co., The, Akron, Ohio......... .......................... ;............................................ 1059 795 ofAmerican Society Heating and Ventilating Engineers Guide, 1936 Page E. K. Campbell Heating Co., 2441-3r5 Charlotte St., Kansas City, Mo................. 909 Canadian Sirocco Co., Ltd., Windsor, Ont., Canada........................... ....... ......... 802-803 Carbondale Machine Corporation, Harrison, N. J...... ........ _....................................... 824 Carrier Engineering Corporation, 850 Frelinghuysen Ave., Newark, N. J................ 825 Celotex Corporation, The, 919 N. Michigan Ave., Chicago, 111.......................... 944-945 Century Electric Company, 1806 Pine St., St. Louis, Mo........................................... 967 Champion Blower & Forge Co., Lancaster, Pa.............................................................. 902 Chase Brass & Copper Co., Incorporated, Waterbury, Conn...................... 974-975, 999 Chicago Pump Company, 2330 Wolfram St., Chicago, III.................................... 992--993 Clarage Fan Company, Kalamazoo, Mich..................................................................... 805 Combustion Engineering Company, Inc., 200 Madison Ave., New York, N. Y....... 879 Consolidated Ashcroft Hancock Co., Inc., Bridgeport, Conn....................... .............. 931 Coppus Engineering Corporation, 339 Park Ave., Worcester, Mass........................... 852 Crane Co., 836 S. Michigan Ave., Chicago, III...................................................... 868-869 Curtis Refrigerating Machine Co., Division of Curtis Manufacturing Co., 1959 Kienlen Ave., St. Louis, Mo........ .................................................................. 826 Davis Engineering Corporation, Elizabeth, N. J........................................................... 928 Decatur Pump Company, Decatur, 111............................................................. ,............ 996 Delco Appliance Corporation, Rochester, N. Y.................... ........... ............ 835, 876, 890 Detroit Lubricator Company, Detroit, Mich......... --............ .............. ............. ,........ 1036 Detroit Stoker Company, General Motors Bldg., Detroit, Mich..!............................. 1032 Dole Valve Company, The, 1901-1933 Carroll Ave., Chicago, 111............................ 1053 Domestic Engineering (a pub.), 1900 Prairie Ave., Chicago, 111........................... ,.... 985 C. A. Dunham Company, 450 E. Ohio St., Chicago, 111................................. 1012-1013 Eagle-Picher Lead Company, The, Temple Bar Bldg., Cincinnati, Ohio--.......... ........ 941 Ehret Magnesia Manufacturing Co., Valley Forge, Pa...... ....................................... 946 Electric Air Heater Company, Division of the American Foundry Equipment Co., 677 Byrkit St., Mishawaka, Ind......................... ........... .......... ....................... 910 Electrol Incorporated, 934 Main Ave., Clifton, N. J........................... ........................ 891 Farrar & Trefts Incorporated, Buffalo, N. Y.... ....... ...................... ........ ............ !..... 882 Fedders Manufacturing Co., 57 Tonawanda St., Buffalo, N. Y.................................. 911 Ferro-Nil Corporation, 500 Fifth Ave., New York, N. Y...... ............ --................. . 1060 Fitzgibbons Boiler Company, Inc., 570 Seventh Ave., New York; N. Y..... . 880-881 Foster Engineering Co., 109-113 Monroe St., Newark, N. J.... .......................,...... .. 1056 Frick Company (Incorporated), Waynesboro, Pa...... _......... ............. ,......................... 827 Julien P. Friez & Sons, Inc., Baltimore, Md ...................... ...............................!-. 1037 Frigidaire Corporation, Dayton, Ohio......................,......... --............ ................. . 806-807 Fueloil Journal (a pub.), 420 Madison Ave., New Ybrk, N. Y.................................. . 986 Fulton Sylphon Company, The, Knoxville, Tenn........... ............ :....... ,.... ...... 1038-1039 G & O Manufacturing Company, The, 138 Winchester Ave., New Haven, Conn..... . 918 Gar Wood Industries, Inc., 7924 Riopelle St., Detroit, Mich....... -- ....... 836-837 General Controls, 1368 Harrison St., San Francisco, Calif.............,......... .......... ..... 1042 General Electric Company, Bloomfield, N. J............. ............... :........................... 838-839 General Electric Company, Schenectady, N1. Y.._..... _...... ........ ............. .......... '968-969 Gilbert & Barker Mfg. Co., Springfield, Mass.... .................................................... 840-842 Grinnell Company, Inc., Providence, R. I............;..... ...... --:....... ..... ...... 919-921,1015 William S. Haines & Company, 12th and Buttonwood Sts., Philadelphia, Pa............ 1020 Hart & Cooley Manufacturing Co., 61 W. Kinzie St., Chicago, 111.... ........... 1002-1003 Hays Corporation, Michigan City, Ind.............i...................... :....... ............ -----...... 932 Heating & Ventilating (a pub.), 140-148 Lafayette St., New York, N. Y...... .......... 987 796 Index to Advertisers Page Heating, Piping and Air Conditioning (a pub.), 6 N. Michigan Ave., Chicago, 111....... 983 Henry Furnace & Foundry Co., 3471 East 49th St., Cleveland, Ohio........._..... 843, 896 Hoffman Specialty Co., Inc., Waterbury, Conn................... 1.................... ....... 1016-1017 Ilg Electric Ventilating Company, 2880 N. Crawford Ave., Chicago, 111................... 903 Illinois Engineering Company, Chicago, 111........................................ ............... 1018-1019 Illinois Testing Laboratories, Inc., 422 N. LaSalle St., Chicago, 111......................... 933 Independent Air Filter Co., 215 W. Ohio St., Chicago, 111............... :.......................... 853 Independent Register & Mfg. Co., 3753 East 93rd St., Cleveland, Ohio................. 1006 Ingersoll-Rand Company, 11 Broadway, New York, N. Y.................... .-............. 828-829 Insulite Company, The, Minneapolis, Minn....................... .............................. ... 948-949 International Exposition Co., Grand Central Palace, New York, N. Y..................... 889 International Fibre Board Limited, Ottawa, Ont., Canada....................................!...- 947 Iron Fireman Manufacturing Company, Portland, Oregon..... ................ ........... 894-895 Jenkins Bros., 80 White St., New York, N. Y.._............ ............. .................... .......... 1057 Johns-Manville, 22 East 40th St., New York, N. Y............................................. 950-951 Johnson Service Company, Milwaukee, Wis............... ............ ................. ...... 1040-1041 Jones & Laughlin Steel Corporation, Jones&Laughlin Bldg., Pittsburgh, Pa.... ....... 971 E. Keeler Company, Williamsport, Pa........................................... .......... ~................... 883 Kelvinator Corporation, Detroit, Mich...................................................... ......... . 808-811 Kewanee Boiler Corporation, Kewanee, 111......... ,........ ........................................ 884-885 Kieley & Mueller, Inc., 34 West 13th St., New York, N. Y............... .......... :.......... 1021 Leeds & Northrup Company, 4941 Stenton Ave., Philadelphia, Pa.._........................ 934 J. E. Lonergan Co., 207 Florist St., Philadelphia, Pa.._..................................... ....... 1022 Lookout Boiler & Mfg. Company, Chattanooga, Tenn.............................. ......... 886-887 McDonnell & Miller, Wrigley Bldg., Chicago, 111.:............. ............................. J.... 858-859 . John H. McGowan Company, The, 54-58 Central Ave.; Cincinnati, Ohio..... ........ ..... 997 McQuay, Incorporated, 1600 Broadway, N.E., Minneapolis, Minn........................... 812 Mercoid Corporation, The, 4201 Belmont Ave., Chicago, 111................................... . 1043 Meyer Furnace Company, The, Peoria, 111................ ........................................ ;......... 846 Minneapolis-Honeywell Regulator Company, 2711 Fourth Ave., So., Minneapolis, ' Minn.......... :.... ...................................... ...................................................... . 1044--1049 Modine Manufacturing Co., 17th and Holburn Sts., Racine, Wis.......... .................. 912 Mueller Brass Co., Port Huron, Mich................................................................... . 976-977 L. J. Mueller Furnace Co., 2009 W. Oklahoma Ave., Milwaukee, Wis........... ... 844--845 MuellerSteam Specialty Co., Inc., 349-351 West 26th St., New York, N. Y.............. 1023 Mundet Cork Corp., 450 Seventh Ave., New York, N. Y................. .......... ............ 952 Nash Engineering Company, The, South Norwalk, Conn.................................... 994-995 National Radiator Corporation, Johnstown, Pa...... ............................................. 870-871. National Regulator Co., 2311 Knox Ave., Chicago, 111...... ........................................ 1052 John J. Nesbitt, Inc., State Rd. and Rhawn St., Holmesburg, Philadelphia, Pa... 922-923 New York Air Valve Corporation, 611-621 Broadway, New York, N. Y.... .......... . 1058 Niagara Blower Company, 6 East 45th St., New York, N. Y...... ..... ............. . 814-815 Norge Division, Borg-Warner Corporation, 606-670 E. Woodbridge St., Detroit, Oil Heat (a pub.), 167 Madison Ave., New York, N. Y..__...... ................. ............... 988 Owens-Illinois Glass Cpmpany, Newark, Ohio.................... .......................................... 854 Palmer Company, The, 426 Clay St., Cincinnati, (St. Bernard), Ohio.........!............ 935 Parks-Cramer Company, Fitchburg, Mass__________..................... ........... ................. 813 Plumbing and Heating Trade Journal (a pub.), 515 Madison Ave., New York, N. Y... 989 Powers Regulator Co., The, 2719 Greenview Ave., Chicago, 111.................. . 1050--1051 0/ and 1936American Society Heating Ventilating Engineers Guide, Page Republic Steel Corporation, Cleveland, Ohio................................................................. 978 Research Corporation, 405 Lexington Ave., New York, N. Y...... .............................. 821 . Revere Copper and Brass Incorporated, 230 Park Ave., New York, N. Y.................... 979 Reynolds Corporation, 19 Rector St., New York, N. Y.._.... ......... :................ . 954--955. Ric-wiL Company, The, Union Trust Building, Cleveland, Ohio............................... 963 Ruberoid Co., The, 500 Fifth Ave., New York, N. Y...... ........................ *.......... 956-957 Sarco Company, Inc., 183 Madison Ave., New York, N. Y............................ 1024-1025 Savage Arms Corporation, 100 East 42nd St., New York, N. Y................................ 816 Serve!, Inc., Evansville, Ind......................................................... 817 Sheet Metal Worker (a pub.), 45 West 45th St., New York, N. Y............................ 990 Silvercote Products, Inc., 161 E. Erie St., Chicago, 111............................................... 953 Somers Air Filter Sales Co., 7310 Woodward, Detroit, Mich...............J.................. 855 Spencer Heater Company, Williamsport, Pa.......................:----.......... -......... , 872-873 Standard Lime & Stone Company, The, First National Bank Bldg., Baltimore, Md... 958 Staynew Filter Corporation, 6 Leighton Ave., Rochester, N. Y........... ..... ................... 856 Sterling Engineering Company, 3730 N. Holton St., Milwaukee, Wis--................ 1026 Streamline Pipe and Fittings Co., Division of Mueller Brass Co., Port Huron, Mich..................................................................................................................... 976-977 B. F. Sturtevant Co., Hyde Park, Boston, Mass......................................................... 908 Taylor Instrument Companies, Rochester, N. Y--............................................... 936-937 Thermal Units Manufacturing Company, 64 East 25th St., Chicago, III.................. 818 H. A. Thrush & Co., Peru, Ind.... ........................................................................... 926-927 Torrington Mfg. Co., The, 50 Franklin St., Torrington, Conn............................ 904--905 Trane Company, The, LaCrosse, Wis............................................................................ 1027 Tuttle & Bailey, Inc., New Britain, Conn............. ......... ................................... 1004-1005 Underground Steam Construction Co., 75 Pitts St., Boston, Mass................... ........ 964 Unit Heater and Cooler Co., The, Wausau, Wis............................................ .............. 913 United States Gauge Co.| 44 Beaver St., New York, N. Y......................................... 938 United States Gypsum Company, 300 W. Adams St., Chicago, 111............................ 959 United States Radiator Corporation, Detroit, Mich..................................................... 874 Universal Copier Corporation, Detroit, Mich................................................................ 831 Utica Radiator Corporation, Utica, N. Y.................................................................... 1000 Vilter Manufacturing Company, The, Milwaukee, Wis......................... .'..................... 832 Vinco Company, lac., The, 305 East 45th St., New-York, N. Y--.......................... 857 Warren Webster & Company, Camden, N. J..................... -.............................. 1028-1030 Waterfilm Boilers Incorporated, 154 Ogden Ave., Jersey City, N. J............i.:-------- 888 Waterloo Register. Company, The, Waterloo, Iowa.................................................. .. 1007 Weil-McLain Company, 641 W. Lake St., Chicago, 111.........................................-.... 875 Westco Pump Corporation, 6 Gaines St., Davenpqrt, Iowa........................................ 998 Westinghouse Electric & Manufacturing Co., Mansfield, Ohio................................... 819 Westinghouse Electric & Manufacturing Co., East Pittsburgh, Pa.................. 970 Whiting Corporation, 15620 Halsted St., Harvey, 111................................................. 1033 Williams Oil-O-Matic Heating Corporation, Bloomington, 111........................... . 848, 893 Wilson & Co., 4110 S. Ashland Ave., Chicago, 111--................................................... 962 L. J. Wing Mfg. Co., 59 Seventh Ave., New York, N. Y.......................................906-907 Wittenmeier Machinery Company, 850 N. Spaulding Ave,, Chicago, 111..--........... 833 Wolverine Tube Company, 1411 Central Ave., Detroit, Mich............................ ........ 980 Wright-Austin Co., 317 W. Woodbridge St., Detroit, Mich................... :........... i-----1031 York Ice Machinery Corporation, York, Pa....................................... ........................... 820 Young Radiator Company, Racine, Wis.:_..................................................................... 914 Young Ventilating Company, The, 2700 Woodland Ave., Cleveland, Ohio............ 849 Zonolite Corporation, Fisher Bldg., Detroit, Mich.................................. _........ . 960-961 798 Air Conditioning Aeriet Air Conditioner Company A Subsidiary of AUTOMATIC PRODUCTS CORPORATION Manufacturers Air Conditioning--Heating--Ventilating--Humidifying Equipment Executive offices: 210 S. Clark Street, Chicago, III., U. S. A. AERIET AIR CONDITIONING UNITS AERIET (Air Cooled) WINDOW UNIT Unit may be installed in any average double-hung sash window. Rests on window sill. Installation com plete in few minutes. Operates from any convenience outlet. No special wiring or water connections required. A compact efficient standardized comfort cooling unit for limited service. Aeriet Window Unit AERIET CEILING UNITS Designed for installation where floor space is limited. Lighting may be combined when desired. Aeriet Ceiling Units are for comfort cooling service only. They are not adaptable for heating. Compact, efficient, economical to install and operate. Capacities one to five tons. (Melting Ice Equivalent.) Ceiling Aeriet -with Lights Ceiling Aeriets without Lights AERIET FLOOR UNITS (Remote Supply) Scientifically developed and properly engineered mechanical units combining every facility and require ment for complete year round air-conditioning. Filter ing, washing, temperature and humidity control with positive circulation. Remote service required. Aeriet Floor Unit AERIET FLOOR UNITS (Self-Contained) Complete year round air-conditioning facilities in a single compact unit. Heating and humidifying may be omitted when not desired. Self-contained Aeriet Air Conditioning Units are water-cooled. Furnished in capacities one-halfto five tons. (Melting Ice Equivalent.) AERIET HEATING AND HUMIDIFYING UNITS For Every Industrial, Commercial, Institutional and Domestic Requirement Write for Catalogue 799 ^ Air Conditioning Airtemp Incorporated 8021 Conant Avenue, Detroit, Mich. Subsidiary of Chrysler Corporation Complete Air Conditioning Systems for all Types of Buildings -- Restaurants -- Stores -- Hotels -- Clubs -- Theatres -- Residences -- Office Buildings -- Hospitals -- Offices AIRTEMP AIR CONDITIONERS Suspended Type Air Conditioners A suspended conditioner to be used for delivery of conditioned air directly into areas to be conditioned or for use with duct systems. Also provides for filtering and circulation of air during mild weather. Quiet in operation and highly efficient in performance. Airtemp Residential Conditioner A concealed Year Round Com fort Unit for apartments and residences. Heats and Humidi fies in winter. Cools and Dehumidifies in summer. Also pro vides for filtering and proper air circulation. Adaptable to Zone Type Installations. The design lends itself to installation where space is limited. Made in various capacities. \ Airtemp Year Round Conditioning Systems Airtemp Year Round Residential Con ditioning System for basement installation. Designed for automatic control of summer and winter air conditions. Heating equip ment can be installed and cooling system added later if desired. The boiler burner unit includes provision for domestic hot water supply. 800 Air Conditioning American Radiator Company 40 West 40th Street, New York, N. Y. Division of AMERICAN RADIATOR & STANDARD SANITARY CORPORATION AMERICAN RADIATOR CONDITIONING SYSTEMS MERICAN RADIATOR COMPANY announces a line of conditioning equip A ment for use with radiator heating. Available at present are two basement type units, one of which is suitable for homes up to 12,500 cu ft, while the other Will provide for buildings up to 25,000 cu ft. ; These units provide for winter humidification, air circulation, ventilation and filtration of air. Air mains conduct conditioned air from the conditioning unit to the rooms where it is desired to introduce this air. It is not necessary to run air mains to all rooms in order to provide for adequate conditioning service in the entire house. The units are equipped with a tempering coil which is connected to the heating boiler. This tempering coil serves to warm the conditioned air so that it can be introduced into the rooms without sensation of draft. The units are regularly furnished for steam, - vapor and high temperature hot water systems. For gravity hot water systems a tempering coil of adequate capacity can be furnished on special order. Control arrangements can be either fully automatic, semi-automatic or manual. The fully automatic control regulates the relative humidity and permits the fan and spray to operate only when there is sufficient heat in the tempering coil. Later on the units will be available with provision for summer cooling, A cooling: coil of suitable capacity will be furnished on special order, which can be used either with a direct expansion refrigerant or with chilled water. The heating system operates entirely independently of the conditioner so that any interruption in the service of the conditioner will not affect the operation of the-heating system. .' -. . .,,. ' ' ... Design and installation guide and complete information on these,units can.be obtained from branches of the American Radiator Company or by writing direct to American Radiator Company, 40 West 40th Street, New York, N. Y. -- WRITE FOR COMPLETE DATA, DIMENSIONS AND RATINGS (See American Radiator Company pages 861-865 and Subsidiaries) . 801 Air Conditioning American Blower Gorporation-Detroit Canadian Sirocco Co., Ltd.-Windsor Division of American Radiator and Standard Sanitary Corp. Branch Offices in Principal Cities of United States and Canada SIROCCO PRODUCTS Manufacturers of Air Conditioning, Heating, Ventilating, .Drying,. Dust Collecting, Dust Separation, Mechanical Draft, Pneumatic Con veying and all types of air handling equipment for more than 50 years A typical Sirocco System of Air Conditioning for large buildings, auditoriums or factories Sirocco Systems Sirocco Systems for cooling, heating, humi difying, dehumidifying and purifying air, in all classes of business and various manufacturing processes, permit control, as desired, of tem perature, humidity and air motion. Component parts: Sirocco or American HS fan and motor, dehumidifier, tempering coils, preheaters, re heaters, spray and circulating water pumps, tem perature and humidity control apparatus and a "Ross" Decalorator, or mechanical refrigeration with accessories. Bulletin No. 2727. Steam Refrigeration (Decalorators) Decalorators are built and furnished in sizes varying in cooling capacity from 24,000 B.t.u. to 48,000,000 B.t.u. per hour. Chilled or decalorized water is produced by the practical application of a well known physical law, namely: water under high vacuum will vaporize at low temperatures. Decalorators will produce chilled water at a temperature of 38 F or above. The Decalorator has no moving parts and water is the only refrigerant used. Completely described in Bulletin No. 2927.. "Ross'* Decalorator Compressor Mechanical Refrigeration For installations involving mechanical refrigeration, the motor-driven reciprocating compressor type of refrig erating machine is supplied. These compressors are available for direct expansion service, or with integral water cooling heat exchanger for use with chilled water as.the cooling medium. This well constructed machine is designed for use with Freon as the refrigerant, and can be furnished in capacities from 1 to 500 tons. Complete details and specifications will be furnished upon request. 802 Air Conditioning American Blower Corporation-Detroit Canadian Sirocco Co., Ltd.-Windsor Division of American Radiator and Standard Sanitary Corp. Sirocco Dekumidifiers and Washers Sirocco Dehumidifiers This line of dehumidifiers, air washers, scrubbers and purifiers, commonly referred to as the Sirocco Washer, is available in standard sizes and designs, constructed of galvanized iron casing and eliminators with welded iron tank. Capacity, 1000 to 300,000 cu. ft. of air per minute. These washers are built in lengths from 4 ft. 0 in. to 24 ft. 0 in. with one to six stages of sprays, depending upon the duty to be performed. Also built of special metal when required. Bulletin No. 3523. Sirocco Conditioners Series "O" Series "O" Sirocco Conditioners are made in four sizes for comfort cooling of restaurants, shops, hospitals, offices, etc. Units are provided with three-speed switch auto matically controlled by means of a thermostat, and can be equipped with wall box for outside air intake. Air filter and humidifier furnished extra. For winter heating, units are connected to hot water boiler. Com plete data in Bulletin No. 2127. Series "0" Conditioner for cooling and heating offices, restaurants and hospitals, etc. Sirocco Conditioner Series "R" The Series "R" Conditioner is a complete conditioning unit for controlling the temperature, humidity, motion and cleanliness of air in the home. For winter heating, is directly connected to boiler (gas, oil or coal fire). For summer cooling, uses tap, ice cooled or refrigerated water. Equipped with a Sirocco electrical control for regulation of temperature and humidity. Conditioned air is distributed by means of ducts. For details refer to Bulletin No. 1127. Sirocco Conditioner Series "B" The Sirocco Conditioner Series "B" is a unit con ditioner and when used with a Decalorator (steam vacuum refrigeration) or mechanical refrigeration, constitutes a simple and complete air conditioning system for department stores, restaurants, coffee shoppes, offices and similar applications. Bulletin No. 3527. 803 Air Conditioning BETZ UNIT AIK COOLER CO. KANSAS CITY. MISSOURI , Licensed under Betz Air Conditioning System Patents COOLS AND DEHUMIDIFIES IN SUMMER HEATS AND HUMIDIFIES IN WINTER COMPLIES WITH ALL REQUISITES OF YEAR AROUND AIR CONDITIONING Utlicools cool and dehumidify in summer, heat and humidify in winter, circulate air at all seasons. The air is cleansed and purified by washing out dust, odors and toxic gases. Unicools provide central station performance plus individual zone control of temperature and humidity. Unicools are designed for installation in, or adjacent to, the space to be air conditioned. The Unicool System is especially adapted for multiple installations in both new and existing buildings, particularly office buildings, hotels, apartment buildings, hospitals, etc. Unicools are supplied in summer with refrigerated water through insulated pipe lines from a central plant. In winter, normal temperature water is circulated through the same lines for humidifying and cleansing. Steam for heating is supplied through separate lines. Hourly Capacities and Dimensions of Unicools Hourly Btu No. Capacities Normal Air Fan Outside Dimensions Cooling Heating Delivery H.P. Width Depth Height 1 19,000 26.400 600 1/40 2 3 53.000 68.500 2150 91,000 119,000 3000 Vi V* 4 I5Z000 204,000 6000 \'h 5 318.000 415.000 13000 3 22* 22* 34* 46* 48* 18* r 6* 30* 8' 0* 30* 8'6* 36* 10'0* 66* 13'0* No. 1 Unicools are equipped with propeller type fans, larger sizes with squirrel cage fans. All sizes available for either right or left hand pipe connec tions and Nos. 2, 3, 4, 5 with vertical or horizontal air discharge. Unicools conserve fuel in winter by providing proper humidification and uniform circulation of heated air within the occupied space. Fin type -heating elements are optional. Unicool Systems provide the advantages of a central refrigeration plant, combined with an air ..washer and fan, without the necessity of large expensive supply and return air ducts. In addition No. l Unicoot they make possible individual control of temperature, humidity and air movement af remote points. No. 8 Unioool With the Unicool System automatic zone control of temperature, humidity and air movement is definitely accomplished regardless of sun location or varying human load. Unicools are vertical spray type units requiring relative small floor space, are con structed with double metal housings with l"_of rigid insulation interposed to prevent condensation and loss of refrigeration. Unicools are durably constructed to assure years of service. Openings in rear of Unicools for admission of outside air connections, are optional. ; Unicools may secure their' refrigerated water from refrigerated shell and tube coolers, from our special constructed insulated water coolers, from steam ejector plants, centri fugal water vapor refrigeration units, or from ice. Unicools may be used for evapor ating cooling arid for purification of air where natural sources of cold water are available. For moderate size installations Unitanks (specially designed water coolers) can be furnished in five standard sizes. For larger installations drawings and specifications of special tanks will be furnished for construction on the job. UNICOOLS ARE COMPLETE CONDITIONERS, THEIR VALUE PROVEN BY YEARS OF FIELD SERVICE. THEY ARE EFFICIENT IN OPERATION AND A QUALITY PRODUCT 804 Air Conditioning Clarage Fan Company Kalamazoo, Michigan Sales Engineering Offices in A1I Principal Cities (Consult Telephone Directory) CLARAGE AIR HANDLING AND CONDITIONING EQUIPMENT For Nearly a Quarter Century Clarage has been a leading manufacturer of air handling and conditioning equipment. There is a Clarage fan, unit or system to meet every need, from the simplest ventilating or cooling job to the most exacting temperature and humidity control installation. Whatever your ventilating, unit heating, cooling, air cleaning, humidifying, dehumidifying or complete air conditioning problem, Clarage can meet your require ments successfully and economically. The Experience of Clarage Engineers covers almost every conceivable type of installation, com mercial, industrial and public building. Clarage equip ment is used in the largest industrial plants, office buildings, auditoriums, theatres, hotels, restaurants, retail stores, hospitals, churches and schools. And lately to the Clarage line has been added the Duotherm, a complete air conditioning unit for fine homes. Clarage Vortex Control System is an important development in air conditioning. It delivers only the volume of conditioned air required by the sensible heat load existing at any given time. Compared to the conventional system, first and operating costs are definitely lower. Architects, Engineers and Contractors will find our service specially helpful. This Company is an independent manufacturer, and to specify and use our apparatus does not involve any binding agreements or license fees whatsoever. Your inquiry for complete data on any Clarage product is invited. Vortex Control System for com mercial and industrial conditioning Modilherm Unit, complete con ditioning plant designed for ceiling or wall installation Duotherm Unit, complete con ditioning plant for fine homes, installed in basement Uniiherm Unit Heater triUi Syncrotherm Control at ttandard equipment 805 Unitherm Unit Cooler for product cooling and refrigeration Air Conditioning Frigidaire Corporation Dayton, Ohio Outlets in All Principal Cities Air Conditioning Division FRIGIDAIRE AIR CONDITIONING SYSTEMS ARE BALANCED Any air conditioning system employing Frigidaire equipment--whether a Unit system or a Central Duct System--gives Balanced Performance because Frigidaire Condensing Units, Unit Conditioners, Evaporators for Duct Systems and Refrigerant Controls are designed and manufactured by Frigidaire for operation one with another. There is a complete line of Frigidaire equipment available for providing either summer air conditioning or year 'round air conditioning for any home, office, business establishment, institution or industrial plant. There are Frigidaire unit con ditioners--self-contained, remote floor- type, suspended type and concealed type-- for providing any or all functions of air conditioning: In addition there is a com plete line of Frigidaire evaporators, con densing units, auxiliary coils and refrig erant controls for all types of central duct systems. Unit Systems--Self-Contained and Remote Frigidaire Unit easily moved to a i 'Conditioners are of new location. four types -- the The Jine of re self-contained floor mote floor type con . , , , models, remote floor ditioners includes ^ models, suspended models for both . . models and con summer air con cealed suspended models;- Of the self- ditioning and year contained type there are seven models 'round air con ranging from a unit of % ton capacity for ditioning. Several single.room applications such as rooms in units, for condition- residences; offices,. etc., to a 3-ton unit particularly adap table for business establishments, where it is desirable All Frigidaire Air Conditioning equipment employs FREON the safe refrigerant developed by Frigidaire, to provide air con General Motors, and DuPont Engi- ditioning equip ment that can be 806 Large capacity sdfcontained unit conditioner Frigidaire Corporation Air Conditioning Typical floor-type remote unit condition er for year 'round air conditioning Typical floor-type, self-contained unit conditioner, approxinately *4 ton capacity ing one large space or are often specified when a selective system several small spaces can is desired, for example in a residence where be operated from a single air conditioning is required in several condensing unit located rooms but not necessarily in all rooms at in the basement, spare the same time. Special Frigidaire re room, closet or other, frigerant control valves installed in a sys convenient location. tem of this kind makes it possible to oper The remote floor units ate several units on a selective basis from a condensing unit of less capacity than the total capacity of the unit conditioners. In addition to floor type con ditioners, there is a complete line of suspended conditioners -- particu larly adaptable for applications where floor space is at a premium. These models can be suspended from the ceiling, placed above window decks or in recesses or concealed behind ornamental grilles. A line of concealed suspended A typical remote floor-type unit instaBatian, units also is available for installation shomag eeoeral conditioning unite operated by a in closet spaces, the conditioned air eingle condensing unit ukich it located in the baeement being delivered through a grill in the wall. Equipment for Central Duct Systems A complete line of evaporators, con densing units, arid refrigerant controls for central duct systems, designed and bal anced to operate one with another, are included in the Frigidaire line of air con ditioning equipment. 5-Way Engineered Evaporators Frigidaire evaporators for central duct systems have five design engineering features: 1. Low pressure drop which insures great efficiency and low operating cost. 2. Counter-flow construction to insure full dehumidifying and cooling capacity. 3. Specially con structed for air con ditioning service; in corporating large sur face area with mini mum overall dimen sions. 4. Low air resis-. tance insuring low operating cost. 5. Matched--to Cross section of a typical operate efficiently, Frigidaire evaporator for singly or in groups, duct system installations showing the manifold type o. with Frigidaire Con construction densing Units. Frigidaire Condensing Units Probably no more convincing argument in favor of the dependability of Frigidaire Air Conditioning condensing units can be offered than the statement that suspended between the wheels on the big majority of air conditioned railroad cars in America, will be found a Frigidaire Condensing unit. There is a com plete line of Frigi daire Air Con ditioning Con densing units--in various capacities ___ --both water- One of the Frigidaire l-eylinder cooled and airWater Coded Condensing Units cooled. A Frigidaire dud system in stallation, em ploying rrigidaire Condens ing Uni!* and Evaporators, in a printing establishment Detailed specifications on the complete line of Frigidaire Air Con ditioning equipment can be obtained from your local Frigidaire Air Conditioning Representative or from Frigidaire Corporation, Dayton, Ohio. 807 Air Conditioning Kelvinator Corporation MANUFACTURERS OF ELECTRIC REFRIGERATION SINCE 1914 Canada: London, Ontario ' Detroit, Mich. Sales and Service Facilities England: London In All Principal Cities Throughout the World Manufacturers of Equipment for: Air Conditioning, Automatic Heating, Water Cooling, Milk Cooling, Beverage Cooling, Household Refrigeration, Electric Ranges, Truck Refrigeration, Ice Cream Cabinets, Commercial Refrigeration AIR CONDITIONING SELF-CONTAINED ROOM COOLER (WATER COOLED) Self-Contained Units are available in several models to provide room cooling for homes and small offices. Capacities range from lA to \ ton of refrigeration per 24 hours. The water cooled con densing unit, cooling and dehumidifying coils, the centrifugal fan, the multi-speed fan motor, air filter, etc., are all located within the cabinet unit. The cabinet is made of high-grade furniture steel finished in rich walnut color and grain design to harmonize with almost every type of surrounding. Top, front and rear panels are removable for inspection. Panels are lined with insulation and isolation materials to prevent the units from sweating and to eliminate all trans mission of mechanical noise. All parts exposed to moisture are rust proofed. FLOOR CABINET AIR CONDITIONING UNITS Floor Cabinet Air Conditioning Units are available in seven models and are ideally suited to homes and offices for single or multiple installations. The Down-Draft cooling and dehumidifying coils, centrifugal fans, quiet operating multi-speed fan motor, air filters, etc., are contained in the cabinet. The cabinet is similar in finish and construction to that of the Self-Contained Room Coolers. The condensing unit and motor is located at some remote place so that the same ,unit can be used for several Floor Cabinet units in simultaneous or alternate operation. Heating and humidifying equipment-can be added in these cabinet units. 808 Kelvinator Corp. Air Conditioning Model* No. FT55DU FT8QDU FT1I0DU FT160DU FT50DC FT75DC FT 100DC SPECIFICATIONS--FLOOR TYPE SERIES Fan Data Over All Dimensions Net Weight H.P. R.P.M. (Max) Speeds C.F.M. (Max) No. of Fans Width Inches Depth Indies Height Lb. Inches Approx. 1/40 960 1 240 2 34% 3%1/40 1140 1/20 1140 1/10 1140 3 3 3 275 390 535 2 2 2 42% 27% 185 31% 230 3% 290 330 1/40 1140 1/20 1140 1/10 1140 3 3 3 275 390 535 2 2 2 34% 42% 42% 17 3iy, 235 31% 295 34% 335 Models with the suffix "DU" are controlled by a thermostat operating with a liquid line solenoid. Models with the suffix "DC" employe a humidistat as well as a thermostat to obtain a closer control of denumiaincauon. ., . . , .A Capacities range from H to 1% tons dependent on temperatures of entering air, location and size of condensing unit used. Consult local dealers for exact selection. G AND CA SUSPENDED UNITS C Type Suspended Unit Suspended units are available in 12 models affording a wide variety of sizes and capacities ranging from to 10 tons of refrigeration. The Down-Draft cooling and dehumidifying coils, air filters, and quiet operating centrifugal fans and motors are inclosed in a sturdy sound absorbing cabinet which is furnished with a prime coat only to permit a finishing coat to match individual surroundings. Heating and humidifying equipment can be added within the units. C AND CA SUSPENDED UNITS--SPECIFICATIONS Model* No. C.F.M. Fan Data R.P.M. (Max.) Motor H.P. Overall Dimensions (Inches) Width Depth Height Approx. Net Weight Lb. C70DU C125DU C2Q0DU C375DU CA400DU CA550DU CA600DU CA900DU CA275DC CA400DC CA500DC CA600DC 265 378 663 1430 1200 1820 1820 2800 1200 1820 1820 2800 1140 1/40 1140 1/20 1120 1/10 1070 1/4 825 825 1/3 1/2 550 1/2 660 1/2 825 825 ' 1/3 1/2 550 1/2 660 1/2 30% 17% 15% 175 31% 22 l?% 215 46% 22 19% 375 46% 33 22% - 450 46% 52% 26% - 46% . 53% 263% 50% 65% 303% 50% 65% 3(P% 590 620 820 835 46% 52% 263% 610 46% 53% 263% 620 501% 65% 303% 820 50% 65% 30'% 835 Models with the suffix "DU" are controlled by a thermostat operating with a liquid line solenoid. Models with the suffix "DC" employ a humidistat as well as a thermostat to obtain a closer control of dehumidification. - . Refrigeration capacity ranges from H to 10 tons, dependent on temperature of entering air. location and size of condensing units used. Consult local dealer for Exact Selection. CS CENTRAL STATION -. .UNITS Central Station units are avail able in several models for capaci- ' ties greater than those of the Suspended units. These units are sectionalized to permit a wide. range of air filter, cooling and de humidifying, heating and humidi fying, and air distribution ca pacities. * 809 Keloinalor Corp. Air Conditioning and Automatic Heating Down-Draft Duct Coil _ DS DOWN-DRAFT DUCT COILS A complete line of Down-Draft Coils are available for installation in existing ventilating and air washing systems to convert such systems to summer air conditioning and cooling. These coils are also applicable to new central station plants. Coils are offered in nominal tube lengths of 20 in., 29 in., 36 in., and 48 in. with capacities per coil ranging from 1 to 10 tons, and multiple arrangements of coils for any desired capacity. The down-draft fea ture of this coil insures immediate drainage of the condensate formed in dehumidification, and uniform distri bution of refrigerant and maximum capacity of the coil. CONDENSING UNITS Kelvinator offers a complete line of air cooled and water cooled Condensing units, ranging in the air-cooled series from 34 H. P. to 5.H. P., and in the water-cooled units from J<j H. P. to 20 H. P. In its more than 21 years of refrigeration engineering and research, Kelvinator has developed condensing unit design and con struction which is of highest quality, in conformity with the best engineering practice, and each unit has been specially devised for the particular requirements of its job. CONDENSING UNITS--SPECIFICATIONS--AIR COOLED MODELS Model No. B625 G633 H650 F675 K6I00 R6I50 Y6200 T6300 T6500 Refrigeration Overall Dimensions (Inches) H.P. No. of Cycles Comp. Capacity R.P.M. Tons per 24 Hours* Width Depth Height Approx. Net Weight Pounds kV* 2 2 %2 %2 2 I'/z 2 22 32 52 415 0.24 315 0.32 340 0.46 330 0.70 310 0.96 310 1.33 280 1.92 260 3.08 375 4.12 25 17% 25% 17% 28 19% 3oy. 23% 35% 24 40 26% 40 28% 44 27% 44 29% \ 18% 1916 19% 21% 23% 26% 27(4 2% 29% 148 183 215 366 408 537 617 750 850 WATER COOLED MODELS WB625 ! WG633 .. WH650 ; WF675 WK6IOO '/* H ` Yl % 1 2 - . 465 2 - 365 2 410 2 400 2 400 0.30 0.40 0.59 0.85 1.36 25% 25% . 29 30% 35 14% 14% 15% 19% 19% 18% 19% 1934 21% 22% 169 195 200 380 413 WR6150 i Vi 2 400 1.88 40J6 . 22% 26% 511 WY6200 ` 2. 2 375 2.55 40% 22% 27% 605 WT6300 3 2 300 3.27 44% 23% SRWT6500 5 2 440 4.80 55% 23% 835 1200 WU6750 WU6IOOO 7% 10 2 2 440 7.00 72& 650 9.95 . 7236 SR' 34% 4354 I960 2035 WV61500 ' 15 4 440 14.00 92% 4354 3095 WV62000 20 4 650 19.90 93% 31 46 2185 ^Approximate one point rating capacity-based on 80 F. Condenser Water Temperature or 90 F. Con denser Air with 37 lb Average Suction Pressure. Consult Dealers for Exact Selection. 810 Kelvinator Corp. Air Conditioning and Automatic Heating KELVINATOR AUTOMATIC HEATING BOILER BURNER UNITS (STEEL) Kelvinator Boiler-Burner Unit offers the heating engineer a compact unit built of welded steel and thoroughly insulated. Exterior metal jacket is rust-proofed, finished with light gray lacquer and trimmed in polished chromium. Outstanding boiler features are cylindrical combustion chamber, single pass tube bank, spiral baffles and thorough insulation. Boiler Burner (Steel) Model No. KB-1 BOILER BURNER UNITS (CAST IRON) Exceptionally compact and attractive in ap pearance, these units provide an unusually efficient sectional cast iron, oil burning boiler, a domestic water heater and oil burner assembled as one unit inclosed in an attractive bonderized steel jacket trimmed with chromium. Moulded combustion chambers, conforming to the natural size and shape of the flame, quickly develop the maximum amount of heat contained in the fuel. The sectional design permits easy installation without altering stairways or doors. BOILER'BURNER UNITS--110 V.--60 CYC. Model No. . Fuel Oil Capacity per Hour Square Feet Radiation Steam Hot Water KBI (Steel) KB2 (Steel) KB3 (Cast Iron) KB4 (Cast Iron) KB5 (Cast Iron) 1.22 Gal. 2.00 GaL 1.66 Gal. 2.6 Gal 3.5 Gal. 565 925 780 1230 1635 850 1400 1170 1845 2450 Steel units have constant electric ignition and line voltage controls. Cast Iron units have intermittent electric ignition, low voltage A. C. controls for 115 V. D. C., line voltage 115 V. D. C. controls. CONVERSION TYPE UNITS Model No. ' Fuel Oil Capacity Gallons per Hour 110 V.. 60 Cyc.. 115 V. D. C. 110 V.. 25 or 50 Cyc. Square Feet Steam Radiation MOV.. 60 Cyc.. 115 V. D. C. MOV.. 25 Cyc. or 50 Cyc. K-i 2.5 2.00 750 550 K-IA 2.0 1.75 600 500 . K-2 K-3 4.5 4.25 1300 1200 7.5 6.50 2200 1900 Intermittent electric ignition low voltage A. C. controls, line voltage D. C. controls. All Units Have: Split Phase Motor; Pressure Fuel Atomization; and require AOBA No. 120 D3 Fuel Oil. CONVERSION TYPE UNIT- MODEL No. K-l Kelvinator Conversion Type Pressure Burner Units for conversion of existing heating plants feature advanced design for long life, economy and trouble-free heating service. Features are: fuel control unit, noiseless, self - priming, non - pulsating pump, adjustable air shutter, scientific fan and housing construction for noiseless operation, directly connected motor with overload protection, air turbulator for complete combustion. These and other features indicate the thoroughness with which Kelvinator adheres to the best engineering practice. 811 Air Conditioning McQuay, Incorporated 1600 Broadway, N.E., Minneapolis, Minn. UNIT HEATERS -- BLAST HEATERS -- CONVECTION RADIATION AIR CONDITIONING COILS--EVAPORATOR COILS--UNIT COOLERS AIR CONDITIONING--BLAST COILS McQuay Extended Surface Coils for Air Conditioning, Central Fan Heating, and for all commercial drying purposes are the result of our many years of experience in the manufacture of heat transfer surfaces. Constructed entirely of non-corrodible materials they are durable, light in weight, and com pact, affording quick economical installation. Specially designed fins are attached to the round seamless tubes under hydraulic expansion, forming a permanent frictional contact between tube and fin, without the use of solder, unaffected by constant expansion and contraction. Tubes are properly orificed permitting a uniform distribution of steam or water into each tube. Tubes are brazed, by special process to round, heavy gauge, drawn copper tube headers, insuring a lasting and trouble-free heat transfer surface. The completed unit is encased in a heavy gauge galvanized housing with provisions for simple and economical duct connections. Since most applications of coils for Air Conditioning and process drying are of a special nature, we offer the assistance of pur Engi neering Department in solving your various problems. McQUAY UNIT HEATERS McQuay Unit Heaters are scientifically designed, engineered, and employ a heating element of the same design as the Air Conditioning and Blast Heater coils. McQuay Unit Heaters are available in twenty sizes ranging from 80 to 1500 sq. ft. of direct radiation making it convenient to select the proper size heater for any heating requirement. McQUAY UNIT COOLERS Available in seven sizes for Walk-In Coolers, Beer Storage Rooms, Truck Refrigeration, etc. For use with all types of refrigeration machines using Methyl Chloride, Freon, Sulphur Dioxide, and other similar refrigerants. Units for Ammonia also available. McQUAY COMFORT COOLERS Available for Water or Brine and Direct Expansion refriger ants. Numerous sizes with capacities to fit your require ments. Floor and suspended blower type units also available. McQUAY EVAPORATOR COILS McQuay coils are designed for practically all phases of commercial refrigeration. Fins made,with a special spun collar hydraulically attached to tinned copper tubes, forming a permanent frictional contact between tube and fin, without the use of solder, and un affected by constant expansion and contraction. All joints are brazed, assuring against leaks ordinarily occasioned by soldered joints. McQuay method of manufacturing makes possible a flexible line of special coils tailor-made to fit your specific requirements. McQuay coils for ammonia installations are also available for all purposes. Bulletins descriptive of all McQuay products available upon request 812 S- '. _ Air Conditioning Parks-Cramer Company Fitchburg, Mass. Charlotte, N. C. Complete Air Conditioning Systems including Heating, Cooling, Humidifying, De-humidifying, Ventilating, Refrigeration, Air Filtering and Air Washing CERTIFIED CLIMATE Certified Climate--Central Station Air Conditioning For health and comfort in Hospitals, Art Galleries, Auditoriums, Restaurants, Stores and Homes. Centrally located apparatus supplies adequate moisture with posi tive pre-determined air change through air washers, heaters--or refrigeration for cooling. Automatic Regu lation essential. : Automatic Aircharger (Not Illustrated) Central Station Balanced evaporation with air change. Insures maximum evaporative cooling in hot rooms in summer. Conserves heat in winter. Positive air circulation and uniformity of humidity and temperature. Mostly for industrial application, ., ` Unit Air Conditioners (Not Illustrated) Various types for industrial or non-industrial use. Similar in pur pose to Central Station, but more portable. Industrial Air Conditioning Helps in many industrifes, notably, Textiles (Cotton, Wool, Worsted, Silk, Rayon, Jute); Printing and Lithographing; Cigar, Cigarette and Tobacco; Clothing; Paper and Envelope, Leather and Shoes, Wood Products; Cereals, Storage of Perishables; Ceramics; Celluloid; Glassine Paper; Starch and Dextrine; Cement. Psychrostat Automatic Regulation The Psychrostat for. accuracy, durability, sensitivity; Hygrostat. (riot illustrated) where requirements are not so exacting. Psychrostat uses the Principle of the Sling Psychrometer. .U. S. Government uses Sling Psychrometer in all Weather Bureau Stations. An Air Conditioning System is no better than its Regulation. Turbo Atomizer Humidifier (Not Illustrated) Spray generated by air under pressure. Water not under pressure and consequently no chance, of leakage. Several fixed capacities. Highest efficiency of any . atomizer. Popular in a wide variety of industrial plants. ' High Duly Humidifier High Duty Humidifier ( Water under pressure, generates spray.. Excess water returned to filter tank and recirculated. Evaporation per unit high; two sizes of heads each with two sizes of nozzles give flexible capacity for varying conditions. Circulation increased by individual motor-driven fan. . Spray thoroughly : diffused and distributed over wide area. 813 / . . . -i '1 Air Conditioning Niagara Blower Company AIR ENGINEERING EQUIPMENT AND SYSTEMS General Sales Office: 6 East 45th Street, New York City Buffalo Boston Philadelphia Cleveland Pittsburgh Detroit Chicago St. Louis San Francisco PRODUCTS--Exact Control Air Conditioning, Humidifying, Dehumidifylng, Drying, Moistening, Chilling, Comfort Systems, Niagara Air Con ditioners, Niagara High Humidity Spray Cooler, Niagara Fan Coolers, Niagara Fan Heaters,. Niagara Aluminum Cooling Coils, Heating Coils. NIAGARA AIR CONDITIONING SYSTEMS For human comfort and for all industrial applications requiring controlled climatic conditions of temperature, relative humidity, air purity and air movement. NIAGARA AIR CONDITIONER, TYPE A--STANDARD ALL ALUMINUM Maintains constantly, or makes any change required in temperature and relative humidity; dries or moistens within tolerance of 1 degree F. and 2 per cent R.H. in processing hygroscopic materials; cleans air most effectively; secures saturation for dehumidifying. Seven sizes. Available both in floor mounted and space saving suspended types. NIAGARA AIR CONDITIONER TYPE C Niagara Type C Air Conditioner Niagara Au Aluminum Surface Coil Air Conditioner, manufactured in 7 meet, both floor mounted and ceiling euepended modete Uses Surface Cooling Coil method for cooling and dehu midifying. Manufactured in sections so that any desired combination of air conditioning functions may be obtained; also solves installation problem in existing buildings as its sections can be brought thru any doors Niagara Air Conditioner, Type A. and erected in confined spaces. manufactured in 7 size*, both floor mounted and ceiling suspended models . NIAGARA SURFACE COOLING COIL METHOD Air conditioning for human efficiency and comfort. A year around operating system providing winter heating and humidifying and summer cooling and dehumidifying for offices, stores, restaurants and all places where people gather. An advanced engineering method introducing, simplified apparatus and controls, for superior operating results, economy and long life, which cut operating costs. ,x NIAGARA FAN COOLER Recommended for comfort cooling, process cooling, low temperature storage for dairies, fruits, meats, food prod ucts,' fur storage vaults, etc. Gives complete circulation of air at desired temperature with even temperature at all points. Manufactured in seven sizes. Niagara Fan Cooler ' Manufactured in 5-, and 4-fan units and in 7 sizes--both floor mounted and .ceiling suspended types Niagan Diet Fan Cooler Manufactured in 7 eieee NIAGARA DISK FAN COOLER . For overhead suspension, saves space and provides the efficiency of moving air cooling for small storage areas, market coolers, etc. Seven sizes. 814 Niagara Blower Company Air Conditioning NIAGARA SPRAY COOLER--STANDARD ALL ALUMINUM For all cooling applications requiring high hu midity or high capacity in small space such as food product applications, especially meat chilling and storage pre-cooling and storage of fruits and vege tables. Prevents drying out, wilting. Also used in industries requiring freezing temperatures such as ice-cream manufacture and frozen food storage. Niagara Spray Cooler is built with cooling coils in a constant brine or water spray. Maintains constant relative humidity as required. Available both in floor mounted and space saving suspended types. NIAGARA FAN HEATERS For the heating and ventilating of,,large areas, Niagara Fan Heaters put the heat immediately Niagara Spray Cooler Illustration of t-fan unit. Also manufactured in 1-, S-, and' 4-fan units and in 7 sizes, both floor mounted and ceiling suspended models where needed in the work ing zone, give quicker heating up to working temperatures. Definitely built to the highest possible standards; welded aluminum heating coils. . Niagara Fan Heater Illustration of 8-fan unit. Also manufactured in 1-, and 4-fan ' units and in 7 sizes, both floor `mounted and ceiling suspended models NIAGARA HUMID HEATER--STANDARD ALL ALUMINUM Recommended for industrial applications where heat and humidity are required as in manufacture of textiles, cordage, printing and paper-converting plants. NIAGARA ALUMINUM COOLING COILS High pressure tested cooling coils are used in Niagara Fan Coolers and Niagara Surface Method air conditioning. Encased, seven standard sizes for blast cooling installations. 20-in. and 30-in. widths. Aluminum coils in aluminum cases. NIAGARA ALUMINUM HEATING COILS For use with fan heating systems giving the advantage of aluminum, light weight and resistance to corrosion. Manufactured in. two widths, 20-in. and 30-in., and in various lengths, giving a complete range of sizes. 150 lbs. working steam pressure. Niagara Aluminum Heating Coils Niagara Aluminum Booster Heaters are used for reheaters to control room temperature indepen-. dently of fan system. NIAGARA DISK FAN HEATERS .Niagara All Aluminum A most effective suspended heater. Operates with lower discharge temperature, cuts down roof and Niagara Aluminum Booster Heater Write for Bulletin Disk Fan Heater wall losses. No. 80 815 Air Conditioning Savage Arms Corporation AIR CONDITIONING DIVISION 100 East 42nd, New York, N. Y. ZEPHYR AIR ZEPHYR AIR equipment includes a com plete line of air washing-humidifying-cooling units for all-year service. Self-contained and remote refrigeration; direct expansion or chilled water. Capacities range from 175 to 4000 cfm and from H to 10 tons refrigeration. The models illustrated are typical of the line. Some are specially designed for multiple installation in office buildings, with chilled water circulated to units from central refri geration. The special deep counterflow coil is used, requiring small water flow and mini mum pipe sizes. SALIENT ZEPHYR AIR FEATURES 1. All-year air washing for effective removal of dust and soluble odors. In Summer, the air is washed before it is cooled, avoiding accumulation of dirt and odors on moist surface of cooling coil. In Winter the air washing provides air cleaning and ade quate humidification. Zephyr 60--Self-Contained AU-Year Model. Capacity to cool one room; to humidify 8 room house 2. Option of finned tube evaporator for direct expansion or special deep counterflow coil for chilled water. 3. Unusually high evaporating capacity for humidification because of dense, finely atomized spray. 4. Extreme simplicity and accessability. 5. Outstanding for quiet operation, troublefree performance and compactness. Zephyr 85-86-88-90 Series--Larger Capacity Models, 600 to 4000 cfm, for cabinet or duct installations ZEPHYR engineers have pioneered the field of unit air conditioning since 1926. The soundness of the patented ZEPHYR ato mizing method and other distinctive features has been proved in thousands of highly satisfactory installations. Now ZEPHYR AIR equipment is produced and backed by Savage with all the advantages of Savage resources and precision manufacturing facili ties. - . .' ; Complete specification folders oh request S10 Zephyr 40--Window Ventilator--<4ir Washer. Will evaporate from 8 to 18 gal water daily Air Conditioning Servel, Inc. Commercial Refrigeration Division Evansville, Indiana AIR CONDITIONING Servel Air Conditioning Units (Floor Type) Handsome units with wood grain exterior, suitable for homes, offices, small stores, shops, etc. While these units are designed primarily for Summer conditioning (Cooling, dehumifying, circulating and cleaning), they can be equipped with a heating coil and a spray-type humidifier for Winter use. Servel Air Conditioning Units (Self-Contained) Completely self-contained, semi-portable Sum mer conditioning units can be installed any where that an electrical connection, a water line, and a drain are available. Ideal for homes, offices, and apartments where it is not practical to place the refrigerating unit at a remote point. Servel Air Conditioning Units (Suspended-Type) These suspended-type units are . designed for restaurants, stores, beauty shops, offices, etc., where limited space precludes the use of a _ floor-type unit. (Can be used in a ducted system or suspended from the ceiling). Capaci ties from 1 to 4 tons. Servel Refrigerating Machine Units Offered in a complete range of sizes and models for every air conditioning need and for every operating condition, from ton to 20 tons. Available with either of two most popular refrigerants. Many exclusive features insure efficiency, economy, and durability. This modern SO-acre plant is the home of Servel Air Conditioning Descriptive Folders and Engineering Data will be sent on Request 817 Air Conditioning Thermal Units Manufacturing Company 64 East 25th Street, Chicago, HI. Representatives in All Principal Cities PRODUCTS--Heaters, Unit; Coolers, Unit; Humidifying Units; Coils, Heating and cooling. Fans and automatic refrigerating compressors for commercial and air conditioning work THERMAL UNIT HEATERS--Six Sizes With permanent one piece--integrally cast-- aluminum element. Ca pacities from 15,000 to 500,000 Btu per unit. No joints, welds, Brazed or soldered con nections. Leakproof, Freezeproof, indefinite life without servicing. Maximum air delivery per horsepower, with lowest outlet air tem perature. Built for troubleproof service and long life. THERMAL UNIT COOLERS--Five Sizes For Ammonia, Brine, Freon, water and other refrigerants. Three types: Circulating, Flooded or direct Expansion. Capa cities from }4 ton to 8 tons refrigerating effect. Employs the same sturdy heat transfer ele ment as our Unit Heater above. Automatic operation, Automatic defrosting, with controls. Eight years of success ful applications, of all types. THERMAL UNIT "V8" AUTOMATIC REFRIGERATING COMPRESSORS Simplicity - Efficiency - Economy--Using Freon or Methyl-Chloride High Volumetric Efficiency - Low Cost - Trouble-Free Operation Eight cylinders and pistons for smooth operation. Silent operation for air conditioning. Light weight, more compact for delivered refrigeration tonnage. Direct Motor drive, vibrationless operation. Pressure lubrica tion,for longer life and fewer wearing parts. Economical opera tion with increased efficiency. Catalogs, information, and Engineering data furnished on request 818 Air Conditioning Westinghouse Electric & Manufacturing Co. Mansfield, Ohio Sales, engineering and service facilities available through local distributors in principal cities w Westinghouse Air Conditioning Equip ment is built exclusively tor air conditioning service. Developed by Westinghouse Re search and Design Engineers, it offers many advantages over equipment origi nally intended for other purposes. Westinghouse equipment is available for either summer or year 'round air con ditioning. It has been especially designed to fit into minimum space, simplifying its installation in existing buildings as well as new structures. air. Powered with the famous Westinghouse Hermetically-sealed mechanism, it has a capacity of 7,000 Btu per hour. Type RW-1 Condensing Unit is es pecially compact in design". Capacity 12,000 Btu per hour. Motor and com pressor are built in a single unit, the water cooled condenser is located in the base. Westinghouse type EL Air Conditioning Unit for stores, offices, homes, etc. When connected to a suitable condensing unit >and steam or hot water heating system, it provides automatic and complete year 'round air conditioning. The Mobilaire is a self-contained sum mer air conditioning unit, providing cool ing, dehumidification and circulation of Type RW-705 Condensing Unit has a capacity of 240,000 Btu per hour. Motor mounted on compressor shaft eliminates belts, flexible couplings and other me chanical drive devices, providing extremely quiet operation and long, trouble-free service. The condenser is located in the bed plate under the compressor and motor. These condensing units are free from vibration, permitting installations to be made without expensive foundations. Units of other sizes are available to meet specific requirements. 819 Air Conditioning York Ice Machinery Corporation General Offices: York, Pennsylvania Direct Factory Branches in 71 U. S. Cities . Complete' Air Conditioning and Refrigerating Systems for maintaining proper atmospheric conditions for industrial pro cesses and human comfort. Available in central and unit sys tems . . . from fractional tonnage up to any capacity required. York Economizer York Freon Refrigerating Unit York Water Cooling System York Economizer: A complete self-contained, combined forced-draft cooling tower and refrigerant condenser. Can be installed out doors, or in ventilated space using discharge duct to outside for rejection of condenser air. Water circulating pump mounted on casing. No condensing water circu lating pump or piping required. York Economizers practically eliminate usual water requirements for con densing and power for pumping water. Power require ments of compressor motor are likewise reduced for seasonal operation of refrigeration or air-conditioning plants. ; York Industrial Spray Type Air Conditioner: (Not Illustrated) . For meat chill rooms, fruit cooling and storage rooms, textile and printing plants, bakery.fermentation rooms and other spaces requiring a constant temperature and relative humidity. In low temperature field, where brine spray keeps refrigerant coils defrosted,-corrosive prob lems are particularly acute. In this York unit long life is insured by welded tank steel casings hot dipped galvanized, stainless steel eliminators, fan wheels and scrolls . . . cadmium plated fan shaft. York Standard Dehumidifiers: Designed especially for air-conditioning applications employing refrigeration. Suitable for theatres, public buildings, stores and office buildings* as part of complete central station systems with controls, fans, motors and air distributing ducts. Available in wide range of standard sizes and capacities; also in special sizes and designs for any commercial or industrial air-conditioning requirement. York Refrigerating Systems for Air Conditioning: . Complete refrigerating systems for use with Freon (F 12) , or Ammonia. Because refrigeration for air conditioning is essentially a water booling problem, York has developed properly balanced, standard water cooling systems for this duty. Designed especially for human comfort applications, Freon was selected as the most suitable . refrigerant because of its outstanding characteristics . . . odorless, non-toxic and non-poisonous, non-inflam mable and non-explosive, non-irritant and non-cor rosive. Freon's thermal properties - make it ideally suited for use in vertical single acting reciprocating compressors. . York Engineering Service: Headquarters for mechanical cooling since 1885 York maintains, on instant call, expert engineers in important centers of demand. York gives, you this important service and invites Architects, Engineers and Contrac tors to avail themselves of it. 820 s Air Conditioning and Dehumidificalion Research Corporation Chrysler Building, 405 Lexington Avenue, New York City COEY MULTI-STAGE COOLING TOWER Patented . "Water Saved is Money Made". Gives: Controlled Cooling, Minimum Noise Level, Sprayless Operation, Archiy tectural Harmony. Because of its compactness, light weight, spray-free and noiseless operation, the Coey Multi-stage Cooling Tower is especi ally well suited to roof and basement instal lation in congested districts; although the highly efficient cooling provided by the multi-stage principle' makes this unit de sirable for installation anywhere. : -. - The tower is built of a copper bearing steel shell, with cypress water baffles and a non-overloading reverse blade centri fugal fan rotor. > . :' Air Movement--Non-overloading centrifugal rotor, high efficiency, variable speed. Principle of Operation--Three pass, counter current flow. ,. No ice formation on fan rotor during winter operation. `- No. G.P.M. 4 25 10 80 26 200 50 400 n8o5 700 900 150 1200 Shape Hexagonal Hexagonal Hexagonal Hexagonal Octagonal Octagonal Short Dia. 3 ft-Wi in. 5 ft-11A in. 8 ft-2v4 in. . 11 ft-P/2 in. 14 ft-4 in. 16 ft-51/2 in. 19 ft-0 in. ' Height 6 ft-4 in. 9 ft-2 in. 13 ft-2 in. 17 ft-9 in. 21 ft-8 in. 24 ft-2 in. 27 ft-8 in. Net Weight * ' Tons Capacity, . *\ .Gas Refrig. ' 1000 lb. . 22001b . :66001b . 145001b 210001b 280001b 380001b . 10 25 - ,70 130 . '225 ' - 300 -400 . . THE CALORIDER SYSTEM OF HUMIDITY CONTROL ;y"' j Removes excess moisture by chemical absorption, with an inexpensive compound known as "Caloride." The system has two distinct functions (1) the control of humidity and air purity for industrial applications, including the drying and purification of various' gases and (2) the control of effective temperature and air purify for human comfort and health. " Cottrell Electrical Precipitation Systems--Multiclone Dust Collectors Inertia Impact Classifiers . ; ". 821 Air Conditioning and Humidification Atlanta, Ga. Boston, Mass. American Moistening Company Established 18S8 Providence, R. I. Chaklotts, N. C. Gbeentolk. S. C. UNIT HUMIDIFYING AND AIR CONDITIONING EQUIPMENT The Amco line of devices for the supply, maintenance and control of humidity is com plete in its ability to meet any presented problem of applied humidification. Used independently or as an adjunct to Central Station equipment, these devices auto matically maintain any required humidity condition in a capable uniform performance. IDEAL HUMIDIFIERS--Senior Type A high capacity unit for use where conditions require a great amount and good distribution of moisture. Motor driven fan gives wide distribution of atomized spray. Amco heads serve the triple purpose of humidifying, air washing and cooling. - IDEAL HUMIDIFIERS--Junior Type Similar in construction to Senior Type. Used where medium capacities are required. ' AMCO ATOMIZER--Self-Cleaning Provided with lever cleaning device--an exclusive AMCO development. Atomized spray is produced by means of compressed air. There is no possibility of water leakage at the nozzle at any time--a distinct advantage of AMCO atomizers. Made in various capacities to meet any required conditions. AMCO HUMIDITY CONTROLS - Compressed Air Operated An extremely accurate and active device operated by compressed air which assures a regulation of humidity within exceedingly close ranges. \' . AMCO HUMIDITY CONTROL Electrically Operated Similar in principle to the Compressed Air Type except that the hydroscopic element operates electrical contacts which control the units. A few of many AMCO products with a Long Record of Dependable Performance Sectional Humidifiers. Amtex Humidifiers. Hand Sprayers. . Mine Sprays. Fabric and Paper Dampeners. Mechanical Psychrometers. Electro Psychrometers. .' Sling Psychrometers. Hygrometers. . 822 Air Conditioning and Refrigeration Baker Ice Machine Co., Inc. 1523 Evans Street, Omaha, Nebr. MANUFACTURERS OF INDUSTRIAL AND COMMERCIAL REFRIGERATION AND AIR CONDITIONING GET FULL SPECIFICATIONS ON BAKER'S COMPLETE LINE Baker pledges full factory co-operation on problems of engineering and installation. Plants and sales offices are situated to give prompt, effective service and information regarding the complete Baker line of compressors, units, and condensers of all types and capacities. Detailed speci fications for your files sent upon request. Baker Ammonia Compressors available in units to 100 tons capacity. Vertical, enclosed, single-acting type, arranged in duplex or multiple for any desired capacity. Synchronous, direct-connected or V-belt drive. Also in auto matic self-contained units ranging from 1 ton to 25 tons capacity at 30 deg suction temperature, two and four cylinder types. Baker Ammonia Compressor Baker Freon or Methyl-Chloride Units in all capacities H to 35 tons at 30 deg suction temperature. . Two and four cylinder air and water cooled types, featuring Timken bearings, double-trunk-type semi-steel pistons and full force feed lubrication. 3 to 35 tons capacity units equipped with multipass shell and tube condensers. Baker Freon or Methyl-Chloride Unit Baker Fan-Type Coldstream Units for refrigerated trucks and commercial air cooling. Rigidly constructed for compact, high-capacity heavy duty service. Finned coil surfaces and air velocity regulated for proper, humidity and temperature conditions. Baker Ceiling Type Coldstream Blower Units designed for comfort cooling or commercial and industrial air cooling. Finned or galvanized bare pipe coil; fans direct-connected or Baker Fan Type ColdStream Unit V-belt driven. Also made as Floor Type Unit in a com plete range of sizes from 2 to 16 tons refrigeration,- 2000 to 16,000 cfm air capacity. Baker Coldstream Brine Spray Units for proper con ditioning and humidification in packing plants, breweries, dairies, fruit cooling and storage rooms, and other applica tions requiring constant temperatures and relative humidity conditions. Available in gravity flow and forced draft types. Equipped with rust-proof eliminators to prevent brine or moisture escaping from the unit. Baker ColdStream Blower Unit --ceiling type, front and rear views . Baker Shell and Tube Condenser Shell and Tube Condensers Baker Condensers and Liquid Coolers made in all diameters and tube lengths up to 2500 sq ft of sur face. Vertical, horizontal, multipass or singlepass types. Baker ColdStream Brine SprayUnit--forced draft type 823 Air Conditioning and Refrigeration Carbondale Machine Corporation General Offices: Harrison, New Jersey District Offices and Representatives in Principal Cities AR-S621 REFRIGERATION SYSTEMS FOR AIR CONDITIONING IN COMFORT COOLING OR INDUSTRIAL PROCESS Complete refrigerating systems for use with Freon (F-12), Ammonia, or Carbon Dioxide, either direct-expansion or water cooling applications. A complete line of refrigeration compressors, permitting im partial recommendations. A nation-wide organization of Dealer-Distributors in major cities to provide sales and engi neering service and plan complete air conditioning systems of the central or unit type. Architects, Engineers, and Con tractors are invited to consult with us. Write to Harrison, New Jersey, for bul letins covering products illustrated below. Freon or methyl chloride self-contained commercial Horizontal COt compressors, single and duplex, units with motors up to S5 hp. and ratings up to 25 tons 25 to 500 hp. Complete installations with condenser' and cooler units Horizontal ammonia compressors, single and duplex; belt, direct motor and steam drive; 60 to 100 tons. Capacity control features available High and low side equipment: Coils, coolers, condensers. receivers, controls, pumps, valves, connections, fittings Air Conditioning and Refrigeration farrier Engineering Corporation AIR CONDITIONING - REFRIGERATION - INDUSTRIAL HEATING Home Office: 850 Frelinghuysen Avenue Newark, New Jersey District Sales Offices: NEW YORK. PHILADELPHIA. CHICAGO. LOS ANGELES Branch Offices and Dealers in Principal Cities Export and Marine Division--Carrier-Brunswlck-International, Inc., Newark, N. J. ENGINEERING - SALES - SERVICE Air Conditioning--(!) Apartment Houses, (2) Auditoria, (3) Banks, (4) Broad casting Studios, (5) Chain Stores, (6) Clubs, (7) Department Stores, (8) Homes, (9) Hospitals, (10) Hotels, (11) Individual Rooms, (12) Libraries, (13) Offices, (14) Office Buildings, (15) Manufacturing; Ceramics, Chemical, Confectionery, Foods, Laboratory Products, Paper, Pharmaceuticals, Printing, Textiles, Tobacco, Miscellaneous, (16) Motion Picture Studios, (17) Public Buildings, (18) Restaurants, (19) Retail Stores, (20) Ships, (21) Theatres. Refrigeration--(1) Chemical Processes, (2) Cold Storage, (3) Food Retailers, (4) Food Serving Establishments, (5) Fur Storage, (6) Marine Applications, .(7) Meat Packing, (8) Product Cooling, (9) Special Applications, (10) Yachts,-(11) Miscellaneous. Industrial Heating--(1) Airplane. Hangars, (2) Armories, (3) Auditoria, (4) Fac tories, (5) Garages, (6) Gymnasiums,' (7) Lofts, (8) Machine Shops, (9) Markets, (10) Public Buildings, (11) Warehouses, (12) Miscellaneous. A Complete Line of Equipment for Every Requirement There is a Carrier system exactly fitted to each requirements and the nearest office of Carrier Engineering Corporation offers a complete service in solving any air conditioning, drying, industrial, heating or refrigerating problem. With an experience of over 25 years in the application of scientific principles every Carrier system is a finely engineered job' which can be depended upon to meet the most exacting requirements. Carrier repre sentatives are trained to analyze special problems and will survey your requirements without obligation. Engineers and architects are invited to make use of this special service. * Carrier Products--A complete line of equipment is manufactured, comprising: (1) Central Station Type air conditioning systems, (2) A complete line of unitary air conditioning equipment, (3) Industrial air conditioning units, (4) Industrial Humidifiers, (5) Individual room units, (6) Residential Air Conditioning Systems, (7) Unit Coolers, (8) Unit Heaters, (9) Centrifugal refrigerating machines, (10) Reciprocating type Refrigerating machines of all sizes and for standard and special refrigerants, (11) Special industrial and marine refrigerating machines. Typical Carrier Equipment for Air Conditioning Steam-jet vacuum cooling equip ment. Chilled water 36 F. or over, i8 to 1000 tons at 60 F. Also centrifugal water vapor units, Vertical ammonia compressors, pressure-lubricated, roller main bearings, safety heads, patented Feather Valves, 2 to 200 tons Special vertical Freon Compressors, pressure-lubricated, roller main bearings, safety heads, uP to 160 tons 60 to 300 tons Compressor requirements above 100 tons are best met by single or duplex horizontal machines. Units up to 750 tons are available, proportioned for Freon and equipped with three-step stuffing boxes. 824 Carrier Centrifugal Refrigerating Machine Carrier De-humidifier and Air Washer Engineering bulletins and descriptive literature on all products available upon request 825 Air Conditioning and Refrigeration Curtis Refrigerating Machine Co. Division of Curtis Manufacturing Co. 1959 Kienlen Avenue, St. Louis, Missouri, U. S. A. CURTIS Air-Conditioning Units These units for air conditioning are outstandingly efficient and trouble-free, the result of 42 years' experience in building fine compressors and compressed-air machinery. The following features are the basis for the low-cost performance of Curtis Air-Con ditioning Units: Extra Capacity--Slow Operating Speed--Experienced Design--Low Upkeep-- Rugged Construction--Fine Materials and Precision Workmanship. ' Curtis enjoys the highest type capital and credit rating--A Curtis product won't become an "orphan." ` Specify Curtis and be sure of a fine job. . Model No. FWH FWH FWH FWH FWH FWH 100-AC 150-AC 200-AC \300-AC 500-AC 750-AC 3Motor Size (H.P.)........................... 1 l'/z 2 5 r/i WBore (In.)...................................... V/s' w 3' y/z` 3' Stroke (In.).................................... 2W w 2Vl' V/l' y/i' 3%' Compressor Speed (R.P.M.)............. 375 375 515 360 425 425 Charge Lbs.-Refrigerant F-12........... 10 12 12 14 18 20 Net Weight Lbs..'........................... 480 510 525 724 856 1375 FWH 1000-AC. 10 3>/2' y/s 450' 20 1500 FWH 1500-AC 15 y/im y/c 600 20 1550 Note: Models FWH-300-AC and larger have Timken Roller Bearing equipped compressors. Models FWH-750-AC and larger compressors are 4-cylinder "V" type design. Units supplied for Methyl Chloride instead of Freon if preferred. ' 826 Air Conditioning and Refrigeration Albant Atlanta Baltimore Boston Buffalo Charlotte Chicago Cincinnati Cleveland Dallas Detroit Des Moines Frick Company (Incorporated) Air Conditioning, Refrigerating and Ice-Making Equipment Waynesboro, Penna. Distributors in 100 Principal Cities Kansas Crrr Los Angeles Memphis New Orleans New York Oklahoma Crrr Palatka Philadelphia Pittsburgh St. Louis- Seattle Washington AIR CONDITIONING WITH FRICK REFRIGERATION Is the term applied to our service in supplying refriger ating equipment and engineering as sistance for com plete air condition ing jobs, which are handled by Frick Branches and Dis tributors -- located in principal cities throughout the world. Estimates cheer fully submitted. 10-Story Office Building at Topeka, Kan., Air Con ditioned Throughout with Frick Freon Refrigeration Get data on special Frick air condition ing systems ar . ranged for auto matic direct-expansion operation. Econo mical, safe, highly satisfactory: let us refer you to typical installations. Ask for Bulletin 504. FRICK FREON REFRIGERATION Includes the most complete line of enclosed type Freon compressors: large capacity, ample gas pas sages, pressure lubrication from internal pump, patented FLEXO-SEAL at shaft. Coils, coolers, conden sers and controls for Freon sys tems. Bulletin 7 Frick Low Pressure Refriger ating Units Air Condition- Jack Dempsey's Restaurant in . 508. New York City AMMONIA REFRIGERATION Machines in all ca pacities from J4 ton up. Com bined units, vertica 1 enclosed type com pressors, horizontal machines: Four Frick From Compressors, Totalling 7SO Tons Refrigeration, are used in Air Conditioning the Wings of the A dministra tion Budding of the Department of Agri culture, at Washington, D. C. complete high and low sides. Widely used for air conditioning. Bulletins 102 to 138. CARBON DIOXIDE REFRIGERATION Six sizes of enclosed COj compressors: smooth running, ef 15-Ton Frtm (/nil for Air Conditioning Work ficient and reliable machines; condens ers, coolers, etc. Bul letins 118, 124, 208. LOW PRESSURE REFRIGERATION Commercial units in more than 50 sizes and types: motors of x/i to 20 hp. Charged with Freon or methyl chlo ride. Air and water cooled condensers. Fin ned coils, fan and blower units, ice cube and beverage coolers, etc. Bulletins 97 and 98. Dozens of Theatres are now Air Conditioned with Frick Refrigeration Frick Enclosed Freon Compressor Enclosed Type Ammonia Compressor Enclosed Compressor for Carbon Dioxide '827 Low Pressure Refrigerating Unit Air Conditioning and Refrigeration Birmingham Boston Buffalo Butte Ingersoll-Rand Company 11 Broadway, New York City Branches or Distributors the World Over Chicago Cleveland Dallas Denver Detroit Duluth El Paso Houston Knoxville Los Angeles Newark New Orleans New York Philadelphia PlCHER Pittsburgh Salt Lake Citt San Francisco Scranton Seattle St. Louis Tulsa Washington CAMERON PUMPS The units consist of standard "Motor- pumps" mounted on 15-, 30-, or 60-gal. tanks and controlled by a float switch. They are suitable for industrial uses, for use in office buildings, apartment houses, department stores, school buildings, estates and clubs, etc. They are often-used to replace inefficient steam traps. Cameron Motorpump There is an efficient, reliable Cameron pump for every purpose. Single-stage centrifugal units range from 5 to 100,000 g.p.m., and multi-stage units (2 to 8 stages) range from 125 to 3000 g.p.m. for pressures up to and over 1500 lb. The Cameron "Motorpump" is ideal for general service everywhere, ranging in sizes from 14 to 40 hp. Pumps and motors are built as one compact and efficient unit on a single shaft. They can be mounted vertically or horizontally on the floor, wall or ceiling. Capacities range from 5 to 1000 g.p.m. for heads as high as 220 ft. single-stage; and from 20 to 275 g.p.m. for heads up to 500 ft. two-stage. Motors for any common current conditions; open, splash-proof, totally-enclosed, or explosionproof types. CONDENSATE RETURN UNITS AIR COMPRESSORS Type "SO" Two-Slaye Comprasor A "Type 30" Air Compressor is an ex cellent source of compressed air for use with regulating devices or control equip ment, and for many other applications re quiring small capacities. It is a selfcontained plant, consisting of a compres sor, driving motor, air receiver and auto matic pressure-control switch. The com pressor is either single- or two-stage, using I-R plate valves. Cylinders and inter cooler are air cooled. Capacities range from 1.2 to 82 cu. ft. per min. Pressures range from 5 to 1000 lb. per sq. in. Ingersoll-Rand manufactures more than 1000. sizes and types of compressors in cluding a complete line of ammonia com pressors. OTHER I-R PRODUCTS "Motorpump" Condensate Return Units are designed to return condensation from radiation systems, heaters, steam coils, etc. Surface condensers; counter-current and ejector-jet barometric condensers; steamjet ejectors; vacuum pumps; centrifugal blowers; air aftercoolers and receivers; Diesel and gas engines; air-and electric hoists; rock drills; and pneumatic tools of many kinds. 828 Air Conditioning and Refrigeration 11 WATER-VAPOR REFRIGERATION The use of water as a refrigerant makes the system 100 per cent safe; eliminates seasonal cost for replacing refrigerant; simplifies installation; and reduces power consumption. Two types of I-R units--Steam-Jet and Centrifugal--permit the selection of the most economical type of equipment to meet widely varying conditions of steam or electric power, cooling water supply and refrigerating requirements. Sustained performance and overload capacity permit a full tonnage rating at the highest chilled-water temperature com patible with the service conditions. Direct evaporation eliminates scaling or fouling of evaporator tubes, and the volumetric capacity of either steam-jet boosters or the centrifugal compressor remains practically fixed for the life of the unit. An overload of 15 or 20 per cent can be carried for peak conditions with only 3 to 5 deg. increase in chilled-water temperature. Because it is simple, safe,: and eco nomical, I-R Water-Vapor Refrigeration has unlimited' uses. It has been applied to: Air conditioning in office buildings, factories, department stores, restaurants, theaters, hospitals, hotels, museums, gov ernment buildings, and cold storage aboard ships. In industry, it is being used in auto mobile factories, chemical plants and rubber mills. Industrial applications are constantly increasing in variety and number. STEAM-JET TYPE CENTRIFUGAL TYPE Quietness and absence of vibration and moving parts characterize steam-jet units. Water, the refrigerant, is evaporated at a high vacuum and the vapor is compressed by highly efficient steam-jet boosters. The water chilled by this evaporation is the cooling medium. The condenser may be of surface or barometric type. Exclu sive I-R features simplify control. Sizes from 10 tons upward. Centrifugal compressors developed by Ingersoll-Rand specially for this service, replace the steam jets where sufficient steam is not available or condensing water, is limited. They can be furnished with electric-motor or highly efficient steamturbine drive. An important feature is self-regulation; units simply float on the load, giving inherently reduced power con sumption with reduced demand. Sizes from 50 to 300 tons. Air Conditioning and Refrigeration Norge Division Borg-Warner Corporation 606-670 E. Woodbridge Street, Detroit, Michigan Electric Refrigerating Equipment for Any Commercial Purpose The Norge line of commercial refrigerating equipment meets every demand from smallest delicatessen refrigerator to the large air conditioning job. Specially designed coils are quickly available if needed. A competent staff of highly trained refrigeration engineers is maintained to insure that everyone who invests in Norge refrigeration for commercial use gets exactly the type of refrigeration he needs. NA-150, hp air-coded RoUator Compressor Blower Coils--Especially adapted to beer, keg storage, dry type milk coolers and similar applications. Fan motors from i4o bp to K hp available for any type current. Air Conditioning and Refrigeration Universal Cooler Corporation DETROIT MICHIGAN 14 Years Experience in Commercial Refrigeration EFRIGERATING machines built by the Universal Cooler Corporation are R meeting the exacting requirements of the air conditioning industry. The line is complete--from the small units for self-contained room coolers to the refrigerating machines for both comfort and industrial cooling. These units can be supplied charged with either Freon or Methyl Chloride, and are applicable to'practically all types of lowside equipment. '- NW-33, hp water-cooled RoUator Compressor. Rollator Compressor Units--Con densing units with motors powered from % hp to 1H hp--air cooled and water cooled. Methyl Chloride used as standard refrigerant. TTTTTr Cooling . Coils--Standard coils meet every requirement for temperature control and humidity. For most installations, coils are made of 1 in. heavy copper tubes with individual aluminum fins. Norge Coil Construction--This dia gram shows how fins are rigidly and per manently bonded onto tubes by hydraulic expansion, thus improving heat absorbing capacity. Reciprocating Compressors -- Con densing Units with motors powered from 1 to 15 hp, using Methyl Chloride or Freon as standard refrigerant. Also available with gasoline engine power. See also Pages 847 and 892 830 Model W1500FH IS Hp UNIVERSAL Cooler condensing units have been developed by engineers fully conversant with the requirements of the air conditioning .industry. During the past few years a great many machines have been installed, and the 1936 line reflects the experience gained on applications of every kind. The executive, sales and manufacturing policies which have guided its destinies are as enduring a part of Universal Cooler as its physical properties. Customers will receive the highest character of service--the public an outstanding degree of product depend ability--always. 831 Air Conditioning and Refrigeration The Vilter Manufacturing Company Since 1867 Milwaukee, Wisconsin For nearly seventy years the name Vilter has been identified as a pioneer in the development of equipment for industrial refrigeration, ice making, cooling, air con ditioning, etc. Vilter Compressors are offered in a complete range of sizes from one ton to several hundred tons. These are available in designs for use of any of the commonly known refrigerants. Self-contained units or indi vidually mounted 'compressors, condensers, etc., according to the application. V-belt or syn chronous motor drive; hand or automatic control. Washers--Designed for in dustrial air conditioning. Posi tive control of humidity, tem perature and circulation of air. Automatic or hand operated. Eliminators incorporated for en trained moisture removal. Odors and . dust- removed by water sprays. No filter replacement. Low cost of operation. Good for low or high temperature cooling. Unit-Type Air Condi tioners--Mono-Unit air con ditioners built in complete range of sizes and types, from the small ceiling unit to large floor units. Dry type, above 35 F, with quiet Plexiform type fan; spray type, below 35 F, with Plexiform type fan; junior, above 35 F, with disc type fan. Super - Capacity Cooler -- High heat transfer from ammonia to water. Exclusive float mechanism assures flooded, trouble-free operation. Unit completely galvanized and built into galvanized iron tank. Completely \non-rusting. No danger of freezing up or of breaking pipes. Shell ana tube type water or brine coolers also available. 832 Air Conditioning and Refrigeration Wittenmeier Machinery Company AIR CONDITIONING ENGINEERS AND CONTRACTORS 850 N. Spaulding Avenue Chicago, 111. 103 Park Avenue New York. N. Y. AMERICAN REFRIGERATING CO Detroit, Michigan H. J. KELLY New Orleans. La. WITTENMEIER MACHINERY CO. Columbus, Ohio WITTENMEIER MCH'Y. CO. of Canada, Ltd. Hamilton, Ontario Wittenmeier, a name associated with Refrigeration in all its phases and applications for over 35 years, offers complete Air Con ditioning and Refrigerating Systems for in dustrial processes and bodily comfort, either in Central or Unit Systems from M ton capacity up. '' . Refrigerants. COs--Freon---Ammonia-- Methyl Chloride--Steam--Water Vapor. When the subject turns to Refrigeration, immediately the name Wittenmeier comes to mind. Credit for introducing and pioneer- . ing the Carbonic Safety System belongs to Wittenmeier. To Wittenmeier also be longs the credit for having developed this system to its present high state of efficiency. Add to this the distinction of having made the very first installation for "Comfort Cooling" and it at once, becomes apparent why the name Wittenmeier occupies such an envious position in the industry and why the Witten meier Machinery Company is classed with Reliable and Responsible Contractors. While our standing in the Industry is reflected in the thousands of CO2 installations that we have made throughout the country, we are, nevertheless, fully equipped and qualified to install any of the systems listed above. Wittenmeier, with Air Cooling and Conditioning Experience that dates back to 1908, can offer helpful suggestions. Architects, Engineers, Contractors and others should avail themselves of this service. Whether room, office, shop, restaurant, bank, theatre, auditorium or large office building, there is a Wittenmeier System best suited for the purpose. Let us make a survey of your requirements and give you our unbiased recom mendations of the system best suited for your needs. There is no obligation. Wittenmeier made the first Hotel Air Cooling Installation. Congress Hotel, Chicago, 111.--1908. Wittenmeier made the first Theatre Cooling Installations. Riviera and Central Park, Chicago, 111.--1918. Wittenmeier made the first Dance Hall installation. The Trianon Ballroom, Chicago, 111.--1921. Other outstanding Wittenmeier installations are Michigan Theatre, Fox Theatre, Book-Cadillac Hotel, Detroit, Mich.; Board of Trade, Hotel Sherman, Southtown Theatre, Aragon Ballroom, Chicago, 111.; Manufacturer's Trust Co., Hotel New Yorker, Capitol Theatre, New York, N. Y.; Loew's State Theatre, United Artists Theatre, Los Angeles, Calif.; New Majestic Theatre and Municipal Auditorium, San Antonio, Texas; Saenger Theatre, Criminal Court Building, Orpheum Theatre, New Orleans, La.; Federal Reserve Bank, Dallas, Texas; Fox Theatre, St. Louis, Mo. There is no substitute for Experience. Wittenmeier Continuously Since 1897 833 -- Air Conditioning Systems (Accessary Units) Air Controls, Inc. Div. of The Cleveland Heater Co. 1937 West 114th Street, Cleveland, Ohio Manufacturers of AIR-PAK Forced Air Heating and Air Conditioning Units, A. C. Blowers and Airate Air Circulators A. C. BLOWER WITH LOUVRES A high efficiency blower for forced air heating and air conditioning installations. Automatic Louvres prevent damage to furnace due to overheating and are essen tial .for safety on oil, gas and coal fired furnaces. A. C. BLOWER WITHOUT LOUVRES A. C. Blowers are quiet and are designed to deliver proper amount of air whether filters are dirty or clean. They occupy small space but deliver large volume of air. Send for bulletin describing them. THE AIR-PAK The AIR-PAK blower-filter unit for forced air heating and conditioning is encased in an attractive red casing with black top. Casing conies in panels and can be assembled in 10 min. without screws, bolts or slip joints. Filters have high cleaning capacity and low resistance. Blower is quiet and free from vibration. All moving parts are rubber mounted. Self-aligning bearings require oiling once a year. Casing has removable back which permits cool basement air to be drawn through filters for summer use. The AIR-PAK is equipped with the famous Patented Automatic By-pass Louvres which permit unobstructed circu lation by gravity when blower is not running. THE AIRATE As shown above the AIR-PAK cari be obtained without louvres when so desired. Send for Simplified Selector Chart and Performance Data. A large volume cir culator for commer cial or attic ventila tion. Attractive, quiet, powerful and economical. Write for bulletins. No. 29 and S. C. 21. 834 Air Conditioning Systems Delco Appliance Corporation Subsidiary of General Motors Rochester, N. Y. ------------------------------------- ---------------------------------------------- Delco-Heat Conditionair One Compact, Completely Harmonized Un;t--Filtering the air which is circulated in the home is one of the most important functions of air conditioning from the standpoint of health. It removes a large percentage of bacteria, pollen and dust from the air. It reduces the amount of cleaning required in the residence and adds life to fabrics and drapes. Humidification of the air, in the winter, is important to health. It reduces the chances of colds and other winter ailments. It also pre vents deterioration of woodwork. Furni ture, with the proper amount of moisture, does not dry up and become loose at the joints. Summarizing: The Delco-Heat Conditionair filters the air, humidifies, automatically heats and circulates the air. which to carry the cooled air from the house back to the Conditionair. Blown Glass Filter Units The operation is simple. The air passes down from the cold air return duct, and travels through the filters, which remove dust, pollen and bacteria. Air passes to the cascade type humidifier and the heating compartment where-it is auto matically heated.. Air in the home is cleaned approximately eight to ten times per hour. Each filter unit has an area of 384 sq in. and is 2 in. thick. The filtering material consists of an upper layer of fine strands of blown glass and a lower layer of extremely fine strands of blown glass. The upper layer of glass strands is approxi mately twice as thick as the lower layer. Strands are covered with a special adhesive material. Models DA-2, and GA-2 have four filter units. DA-3 has nine filters. Model DA-1 has two filters. Ample Heating Surface to Maintain Temperature Desired--The especially de signed combustion chamber and heat pas sages are unique in construction. They expose a large heating surface to the air as it is circulated over the stream-lined unit. Rapid heating with great economy of fuel results. The Delco-Heat principle of combustion gets full heating effects from low cost domestic fuel oil. Completely Automatic in Operation-- The thermostat, set to the desired tem perature, controls the operation of the Delco-Heat Conditionair. Central Plant Duct System--The DelcoHeat Conditionair requires a central plant duct system. A main distributing duct, from which branch ducts go to individual rooms, is taken from the top of the unit. Return ducts are recommended through Delco-Heat Conditionair (Oil or Gas Burning) Automatic Controls for Conditionair Delco-Heat Conditionair is available oilfired in three models; model for natural, artificial or mixed gas also available. Sturdiness, positive alignment of moving unit assures quiet operation due to freedom from vibration and rattle.- No part of the Delco-Heat mechanism is in the combus tion chamber, thus warping, burning out, and corrosion are eliminated. All controls needed for automatic heating are standard with the Delco-Heat Conditionair. ' See also Pages 876 and 890 835 Air Conditioning Systems Gar Wood Industries, Inc. AIR CONDITIONING DIVISION 7924 Riopelle Street, Detroit, Mich. Licensed Distributors in All Principal Cities TEMPERED-AIRE UNIT Tempered-Aire heating and air conditioning equipment includes fil ters, blower, humidifier, furnace (with "Economizer") and integral oil burner of pressure atomizing type. Cloth filters can be easily, laundered. AH units can be equipped with a water heating coil for use in winter. The installation of an auxiliary duct for intake of outside and basement air in summer is desirable. Air can then be drawn from the basement during the day and from the outside at night to provide ventilation and cooling during warm weather. Change from basement air to night air may be manually or automatically controlled. - Ratings and Dimensions Btu 1 Hour at Bonnet........................................... Btu 1 Hour at Grilles............. `............................. Air Delivery, CFM.................................................. Heating Surface, Firebox, Square Feet.................. Heating Surface, Economizer, Square Feet........... Total Heating Surface............................................. Overall Length; Inches............................................ Overall Width, Inches........................................... No. 102 120,000 100,000 1000 to 1575 30 60 90 96% -40 No. 103 165,000 135,000 1375 to 2150 33 99 132 117% 40 No. 104 225,000 185,000 1875 to . 2950 44 132 176 140'/, 40 No. 105 300,000 245,000 2500 to ' 3925 . 55 165 220 156% 40 No. I0S-C 400,000 3000 to 4500 55 165 220 156% 40 CONVERSION OIL BURNER--Pro vides automatic oil burning equipment for coal fired heating plants. Pressure ato mizing type, handle heavier, cheaper grades of fuel. Sturdy, noiseless, easily accessible. MODEL "0" AUTOMATIC OIL FIRED WATER HEATER--Provides quick, convenient, less expensive and un limited supply, of domestic hot water for industrial and commercial buildings. Com plete, quiet. Burns low priced No. 3 fuel oil. Model "K" . Extremely flexi ble, due to system of triple range blowers and two motor speeds. Handles capacities from 412 to 2500 sq ft net steam radiation. Model "H" An efficient, low cost unit, to supply automatic oil heat for small homes. Handles capacities up to 625 sq ft net steam radiation. Capacities and Dimensions Two sizes, 200 and 300 gal ca pacity. 100 F rise per hour. Overall height 48 in. Overall width 2&H in. . - Length 49 in. and 61 in. re-, spectively. 836- Gar Wood Industries, Inc. Air Conditioning Systems MODEL "R" BOILER-BURNER UNIT A compact, fire-tubular steam or hot water heating boiler, with an integral oil burner. . Boiler built of heavy rust-resisting boiler plate, electric ally welded. The combustion chamber walls are carried clear to the crown sheet. The result is a considerably higher temperature of fire than is found in the conventional boiler, and better combustion of No. 3 oil. Since there are no water legs, the bulk of the heating surface is concentrated in the firetubes, or secondary heating surface, resulting in maximum extraction of heat from the hot gas which leaves the firebox and consequent low stack temperature, high efficiency and operating economy. . Ratings and Dimensions Maximum Net Steam Load, Square Feet............. Maximum Net Hot Water Load. Square Feet---Maximum Gross Steam Load, Square Feet.......... Maximum Gross Hot Water Load, Square Feet. Heating Surface. Squire Feet................................ Overall Width, Inches............................................ Overall Length, Inches......................................... . R475 . 475 760 712 1140 52 30hi 53 R750 750 1200 1125 . 1800 68 3054 65 RI000 1000 lf.00 1500 2400 84 37% 59% RI400 1400 ' 2240 2100 3360 118 37% 66 RI800 1800 ,, 2880 2700 4050 ' 154 37% 80 MODEL "J" BOILER-BURNER UNIT A deluxe, down-draft, steel, steam or hot water heating boiler of unique design, equipped with its oil burner, all beautifully finished to give discriminating owners not only an efficient but handsome unit. The design of boiler gives a maximum of heating surface resulting in almost complete heat transfer. Gar Wood external indirect water heaters are available for both Model R and J boilers, to provide year round domestic hot water. . Ratings and Dimensions Maximum Net Steam Load, Square Feet............. Maximum Net Hot Water Load, Square Feet.... Maximum Gross Steam Load, Square Feet.......... Maximum Gross Hot Water Load, Square Feet,.. Heating Surface. Square Feet................................ Overall Width, Inches............................................. Overall Length, Inches........................................... No. 5 500 800 750 1200 72 31% 42V, No. 8 800 1280 1200 1920 105 31% 50% - No. 12 1200 . 1800 1800 2880 152 31% 60% No. 16 1600 2400 2400 3840 199 31% 71% No. 16-35 2800 4480 4200 6720 199 31% 71% INDIRECT AIR CONDITIONING CABINET Combined with "R" or "J" boilers, it provides heating, humidifying, filtering and circulation of air. . The air drawn by blower, is first cleaned by dry cloth filters, then forced through the humidifying chamber, where proper amount.of healthful moisture is added by passing through a warm vapor mist, regulated by. a room humidistat. The air is then warmed to correct tempera ture by passage through the copper blast heater. Standard units, in capacities from-- : 111,000--497,000 Btu Hour at bonnet . 89,000--397,000 Btu Hour at grilles ; 837 Air Conditioning and Automatic Heating Systems GENERAL ELECTRIC COMPANY AIR CONDITIONING PRODUCTS Air Conditioning Department, Bloomfield, N. J. FOR AIR CONDITIONING, INCLUDING AUTOMATIC HEATING A Complete Line of Equipment for Summer, Winter, and Year 'Round Application G-E UNIT ROOM AIR CONDITIONERS For Summer Type FC-2 cools, dehumidifies, venti lates, filters. Requires no piping con nections or special wiring. Has three hermetically sealed condensing units. Other G-E types have condensing units remotely located, and may be installed in multiples with one condensing unit. For Year 'Round G-E units toVprovide automatically cooled, dehumidified air in summer, and warmed, humidified air in winter are avail able either with condensing unit built in (Type FR-1) or remotely located (Types G-E Store Cooler Wall or ceiling mounted. Cools, de humidifies, and circulates air. Has G-E Aphonic type fan. (Types AG-10-12 and 15). G-E Air Circulator Removes over heated air by day; draws in cool out door air at night. Effectively installed at attic windows in homes. G-E Condensing Units Exceedingly flexible range--1 hp to 20 hp--to accurately fit any need and assure economical operation. G-E Air Condi tioner for Warm Air Systems (Types AA-3 and AA-4) Combined with G-E Oil or Gas Furnace, provides heated, humidified, filtered, and circu lated air. Fan draws air from re turn duct through steel wool filters, passing over steam heating surface and humidifying screens to delivery ducts. Humidifying water is heated by indirect coil, flow controlled by magnet valve operated by humidistat. Cooling equipment for summer can be added easily. 838 Air Conditioning and Automatic Heating Systems GENERAL ^ ELECTRIC COMPANY AIR CONDITIONING PRODUCTS Air Conditioning Department, Bloomfield, N. J. G-E Oil Furnace--(Two sizes--Types LA-4 and LA-5)--Fully coordinated--Boiler, burner, water heater, controls in one enclosed unit, all made and guaranteed by G-E. Can burn cheap grades of oil-- to produce low cost heat. Employs entirely new principle of oil atomization. Heavy arc-welded steel boiler with water - backed combustion chamber. Low standby losses. Sub-atmos pheric pressure prevents escape of odors. Large, non clogging oil orifice. Non-drip nozzle is air cooled. All con trols built-in, including four second self-checking flame detector. Expansion relief door with electric cut-out. Synchronous motor-driven primary control and electric clock thermal control. All rotating parts on one shaft, automatically oiled, completely sealed in. Burner head, motor compressor, controls separately and quickly removable. G-E Gas Furnace--All parts by G-E, fully coordinated fer high efficiency. Plain or de luxe jacket. RM (small residential) Series, 4 sizes, A.G.A. steam ratings 320 to 800 sq ft. RK (larger residential) Series, 6 sizes, A.G.A. steam ratings 660 to 1760 sq ft. CK (commercial) Series, 14 sizes, A.G.A. steam ratings 1980 to 9680 sq ft. Automatic secondary air control on RK and CK reduces standby losses, conserves fuel. Automatic control of steam pressure, low water cut-off, and temperature .limit. Safety controls are gas operated to assure positive action. Boilers meet A.S.M.E. Specifications and carry A .G.A. approval. G-E Warm Air Conditioner, Oil Fired (Type LB-4)--r Consists of combustion-heat transfer unit, oil burner unit* centrifugal fan, humidifier, filters, controls, and necessary air, oil, water; and electrical connections. Completely enclosed in attractive two-tone gray cabinet, black and chrome trim. Of direct-fired type, developed especially for residential air con ditioning, it circulates clean, warm, moistened air through ducts. G-E thermal control and anti-syphon screen valve included. Total output, 133,000 Btu per hour; humidifying, 10 lb per hour. Extremely quiet; electrically welded air-tight furnace--no place for gases and odors to escape; flame detector shuts off oil in less than four seconds; burns cheap oil on ex clusive G-E impact-expansion principle; sealed-in-steel motor, self-lubricated; burner nozzle air cooled. See also Pages 968 and 969 ' Air Conditioning and Automatic Heating Systems Gilbert & Barker Mfg. Co. SUBSIDIARY OF STANDARD OIL CO. (N. J.) "Gilbarco" Automatic Oil Heating and Air Conditioning Equipment Springfield, Massachusetts GILBARGO FLEXIBLE-FLAME OIL BURNERS FOR ALL TYPES OF HEATING PLANTS Complete Range of Models 700 to 10,000 Sq Ft of Steam Radiation 1120 to 16,000 Sq Ft of Hot Water Radiation "Gilbarco" Flexible Flame Oil Burners are of the pressure atomizing type, suitable for residential and commercial use in steam, hot water, vapor, or warm air heating systems. Their operation is fully automatic with controls and safety devices integral with the sys tem. Due to the flexibility of the flame, the "Gilbarco" Burner is enabled to more completely fill the fire box with a heat-giving radiant flame. . Each "Gilbarco" Burner combines the following definite advantages: 1. Flexible Flame Combustion---assuring tailor-made application. 2. Forced draft--insuring com plete combustion. 3. Radiant type flame--gives great heat output. .4. Constant electric ignition. 5. Separate air and oil controls, insuring complete combustion.' 6. Oil filter in oil line--assuring clean oil at all times. 7. Radio interference eliminator. 8. Burner installed outside boiler insures long life, easy inspection and service and general operating efficiency. 9. Quiet operation--no gears, belts or disturbing noisy mechanisms. SPECIFICATIONS OF AND CAPACITIES FOR 60 CYCLE MOTOR BURNERS (Write to us for capacities of D.C. and odd cycle motor burners) MODEL NUMBER Max. on Capacity pr bwr, UECilfow si-ipo 2 JB4 3.15 . 364 5.25 . *B$10 11.0 *CS26 15-00 cs.to 25.00 Total Steam Radiation (Radiation, pipte*. ta4 pickup) 700 1200 2000 4400 6000 ' 10,000 Total Hot Watte Radlsttoa . (Radtatioa, piptaj, and pickup) . 1120 1920 3200 7040 9600 16.000 . Iftsltioa Continuous transformer Continuous electric single transformer Continuous transformer Continuous electric single transformer Continuous electric two transformers Continuous electric two transformers Motor (rise) 1/12 H. P. 1/8 H. P. 1/S H. P. 1/6 H. P. 1/3 H. P. 1/3 H. P. CoatroU Stock mounted protectorelay and Thermostat Stock mounted Protectorelay and Thermostat Stock mounted Protectorelay . and Thermostat Protectorelay Protectostat and Thermostat Protectorelay Protectostat and Thermostat Protectorelay Protectostat and Thermostat RPM 1150 1150 1750 1750 1750 1750 Outside view of the " B'7 Series Gilbarco Boiler Burner Unit. The lower-center panel on the "A " Series is perfectly plain. GILBARCO SERIES "A" BOILER-BURNER UNITS There are three models ^or both steam and hot water systems in the "A" series which range in capacity from 350 ft of net standing radiation to 550 ft of net standing radiation for steam and 560 ft to 880 ft of net standing radiation for hot water. The boiler, especially designed for oil fuel, is of cast iron, which can be moulded into the most effective kind of heat-absorbing surfaces. "A" series models are completely automatic and the high efficiencies which are attained in the boiler aire due to the fact that the heat gases are compelled to be in direct contact with the heat-absorbing surfaces at all times. All series "A" Gilbarco Boiler-Burner Units are de signed to include: Built-in hot water coil and aquastat; Lowwatercut-off on steam systems; Pre-cast refractory' combustion chamber; " Pressuretrol" on steam systems; Surface aquastat on hot water systems. 840 Air Conditioning and Automatic Heating Systems No. A-22 steam Gross Net 548 350 700 450 860 550 SERIES "A" RATINGS HOT WATER Gross Net 876 560 1120 720 1376 880 DOMESTIC WATER-COIL CAPACITY Steam Hot Water (at 150") 40 gallons 40 " 40 " 20 gallons 20 " 20 " CHIN NEY Size Height Ins. 8 x 12 30 8 x 12 30 8 x 12 30 *9 GILBARCO SERIES "B" BOILER-BURNER UNIT There are five models for both steam and hot water systems in the "B" series which range in capacity from 500 ft to 1300 ft of net standing radiation for steam, and 800 ft to 2080 ft of net standing radiation for hot water. Like the "A" series units, the boilers of the "B" series are of cast iron con struction insuring peak efficiency and exceptional durability. The specially designed boiler combines the following important efficiency factors: (I) Extended fin type heating surfaces. (2) Low draft loss. (3) Large combustion chamber. (4) Quick steaming. (5) Water-backed combustion chamber. (6) Ground joints between sections. (7) Unique gas travel. . (8) Positive internal water circulation. (9) Large steam liberating surface. (10) Compact size. SERIES "B" RATINGS STEAM No. Grots Net HOT WATER Gron Net DOMESTIC WATER-COIL CAPACITY Hot Water ( 150*) CHIMNEY Sue Ins. B-3 780 500 1248 800 100 gallons 50gallons 6x12 30 B-4 3095 700 3743 1120 100 50 " 8x 12 30 ' B-5 1403 . 900 . 2248 1440 100 " -50 8x 12 35 B-6 1720 1100 2752 1760 . 100 50 * 12 x 12 35 B--7 2030 . 1300 3246 2080 100 " 50 12x12 40 IE Si IE ns M am Note.--All domestic water heater ratings are based on 50-150 F. rise in three hours at a minimum boiler water temperature of 180. F. In hot . waterboilers it will be proportionately less de pending on operating water temperature. Net rating means actual standing, cast iron radiation, piping and pick up losses having been allowed for. It does not, however, include domestic hot water load, and this should be deducted at the rate of 0.75 sq. ft. (steam) or 1.2 sq. ft. (water) for each gallon of storage heater capacity. Efficiency--Series "A" boilers show a test efficiency of 77%, Senes B boilers show a test efficiency of 80%, plus over-all at rated capacity for continuous firing. Note.--When ordering be sure to specify whether the unit is for a steam or hot water system 841 Air Conditioning and Automatic Heating Systems GILBARCO SERIES "F" AIR CONDITIONING UNITS HEAT - CLEAN - HUMIDIFY - CIRCULATE "Gilbarco" series "F" Air Conditioning Systems are efficient, dependable and un usually economical in operation. They are specially designed for oil fuel and develop a high degree of heating efficiency. The oversized radiator within the furnace, with its long, retarded gas travel insures a great amount of heat with economical fuel con sumption. The filtering and humidifying equipment is engineered according to advanced principles of this new science and the fan and motor are of sufficient capacity and dura bility to insure many years of efficient service. . Model FBSS7100 Model FBRS7100 Filter-Washer-Blower Unit SPECIFICATIONS "GILBARCO" SERIES "F" AIR CONDITIONERS UNIT NOMBERS* B.T.U. Burner Burner! BLOWER DIMENSIONS (Incbe*) Smoke CHIMNEY Without Waxher With ,, Model Endoied C-F.M.t Fin Motor Filter* f A B C D E F Wuher Rejmer No. Mix. Di*m. H.P. No Site (In*.) Pipe Dt*m FINISH Sixc Heifht Ina. Ft. FBR27I0O FBS27100 100,000 S2 100.000 &2 No No 1400 1400 12 12 F8O22120 FBOW22I2C 120.000 S2 PBS27150 FBSW27IJO 1)0,000 $2 FBD27200 FBOW2720C 200,000 S2 FBSJ22J0 FBSW122JO 2)0.000 JB6 FRStfjOO FBSWJ2300 WO,000 JB6 FBS})400 400.000 JB6 FBSJJ475 47),000 JB6 Ye* No f Ye* No f -No t No t No f 2000 2200 2)00 MOO 4000 woo ' 6000 12 16 16 18 18 21 ' 21 x 2 16 x 2) 46 Di* 72 58 8* Cxlvuixed 8x8 50 X 2 16 i 2) 4) 45 69 58 \ 8* Safe Green, 8 x 8 50 Ripple Enamel X 4 20 x 20 4) 51 11 Vj 61 8* Green Flintflex 8x8 W X 6 16 x 2) 50 5) x 61 26 14 * Gray Flintflex 8 x 10 50 X 6 16 x 2) 54 65 S2X 61 9* Green Flintflex 8 s 12 50 X 6 20x20 61 61 d 9? 6) 26 27 9' Gray Flintflex 10 x 12 W X 9 20x 20 61 61 J 97 6) 26 27 9' Gray Flintflex 10 12 30 X 12 16 x 20 61 67 97 n* 26 27 10* Gray Flintflex 12 x 12 >2 i 12 16 a 20 61 67 9? 26 27 10' Gray Flintflex 12 x 16 54 FBSM600 600,000 BStO No 55 120 91 - 12' Galvanized 16 16 36 FBSMflOO 800,000 bsio No SPECIAL 55 120 91 - 12' Galvanized 16 x 20 40 F indicicr* "F*` Serin B` Blower R* Round Cue S" Squire Cue - D" Oe Luxe Cue Finish W* Washer fVestibule Burner Enclosure can be furnished at extra cost tC.F.M. foe Normal Static Pressure and Fan Speed {VitcoutType Renewable Filters - 842 Air Conditioning Systems Henry Furnace & Foundry Co. 3471 East 49th Street Cleveland, Ohio MONCRIEF GAS FIRED AIR CONDITIONERS, OIL FIRED AIR CONDITIONERS AND COAL FIRED AIR CONDITIONERS MONCRIEF GAS FIRED AIR CON DITIONER. Approved by A merican Gas Associa tion. Burns mixed, arti ficial or na tural gas. MONCRIEF ARISTO CRAT OIL FIRED AIR CONDI TIONER. Specially de signed and constructed for oil burner service. Ac commodates any standard oil burner. Heats, cleans, humidifies and distributes the air through forced circulation. Re frigerating and dehumidifying equipment for summer cooling can be readily incor porated if desired. High efficiency in heating and low oper ating cost are achieved by means of special construction of burners and heating sections. See table below. The product of 38 years' experience. Made in three sizes: No. 200 delivers at register 118,465 Btu. No. 240 delivers at register 150,360 Btu. No. 300 delivers at register 200,475 Btu. Develops as high as 83 per cent efficiency at bonnet. Complete catalog and table of dimen sions and capacities furnished on request. . MONCRIEF GAS FURNACES FOR AIR CONDITIONING SYSTEMS j Furnace No. II 1Type B and 1 [ Type C Width [ t/i Type C Less * Blower Length 8. Type C with Blower Length -g Type B Height | | l 8 Type C Heightj | Dia. Flue Pipe 1 Size Gas Line Heating Surface | Casing Free Area [ Velocity Thru j Furnace Btu Input Forced Air Btu at Register C.F.M. Blower Size 1 No. of Filters Velocity Thru i Filters Gravity Btu at Register Gravity Pipe Area ze of Js 8? -2.3 C0 a. c 5 02 'o gj 6 HCQ Z 50 12 44 48 1 3 100 19 44 52 85 5136 54 2 4 150 26 44 52 85 51*6 54 3 5 200 34 44- 52 88 5 Ufa 54 4 6 250 41 44 52 88 51% 54, 5 7 300 49 44 52 88 51*6 54 6 8 350 56 44 52 88 5i % 54 7 8 400 64 44 52 88 5136 54 8 9 450 71 44 52 88 5136 54 9 10 500 78% 44 52 88 5)36 54 10 10 600 94% 44 52 88 51% 54 12 10 CL X 5 o 2 % 2160 233 30,000 19,125 170 1 4320 376 215 60,000 42,750 560 110 % 2 105 38,250 281 1 6480 438 277 90,000 64,125 840 110 % 2 158 57,375 422 1 8640 584 277 120.000 85,500 1120 112 % 3 140 76,500 562 i% 10800 730 277 150,000 106,875 1400 114 V, 4 131 95,625 703 i% 12960 976 248 180,000 128,250 1680 212 M .4 158 114,750 844 i % 15120 1146 246 210,000 149,625 I960 212 M 5 147 133,875 984 i% 17280 1166 277 240,000 171,000 2240 214 'h 5 . 168 153,000 1124 i % 19440 1314 276 270,000 192,250 2520 214 'h 5 183 172,000 1265 i% 21600 1376 293 300,000 213,750 2800 214 'h 6 175 191,250 1406 i'a 25920 1678 288 360,000 256,500 3360 120 Vs 6 210 229,500 1688 Type B Furnace Casing has manifold exposed and is designed for gravity use. Blower and filters can be added as separate unit. ' Type C Furnace Casing has manifold enclosed and is designed for blower-filter use. Can be used' for gravity circulation if desired. . Forced Air Btu Ratings are based on efficiencies of 75 per cent at bonnet and 95 per cent at register. Gravity Btu Ratings are based on efficiencies of 75 per cent at bonnet and 85 per cent at register. G-E.M. Capacities are based on 70 deg room temperature and 135 deg register temperature. . Add 11 in. to overall height for 14 in. pitched top used with Type B Casing. _ . ' . See also Page 896 843 Branches St. Loots Memphis OUAIIA Minneapolis Salt Lake City Dallas Air Conditioning Systems L. J. Mueller Furnace Co. Established 1857 2009 W. Oklahoma Ave., Milwaukee, Wis. Branches Los Angeles New York Baltimore Philadelphia Pittsburgh Boston MUELLER OIL-FIRED AIR CONDITIONING UNIT The first complete departure from conven tional furnace design in a direct-fired, forced air heating and air conditioning plant. The basic design, covered by patent claims allowed and pending, secures a new standard of efficiency and reduced fuel cost. The compact simplicity of design, reducing thermal ca pacity, secures instant heat and eliminates parasitic losses, slow response and tempera ture override which occur with heavy fur naces. Heats, humidifies, filters, and'circulates the air, completely controlling iijdoor winter climatic conditions, and if desired, cooling and dehumidifying. MUELLER CLIMATOR AIR CONDITIONING SYSTEMS The equipment shown is designed to handle all functions of both winter and summer air conditioning. Heating unit may be any type Mueller furnace for use with coal, oil or gas. Where winter con ditioning only is desired, dehumidifica tion and temperature reduction equip ment is omitted. Climator units are available in a range of sizes to provide complete or partial conditioning for any size residence. MODERNAIRE UNIT (At left). For installation in space to be heated. Heats, filters and humidifies the air and distributes by forced circulation. Heat transfer units are Gas Era pressed steel sections. Fan operates automatically when furnace is in operation. Four sizes, with A.,G. A. input ratings from 90,000 to 225,000 Btu per hour. GAS ERA BOILERS The Series A Gas Era Boiler, at right, is adaptable to steam, hot water or vapor heating in smaller residences. Boilers are of standardized sectional cast iron con struction, equipped with completely in sulated lacquered casing, concealing sec tions, controls and diverter. Nine sizes with A. G. A. ratings from ISO to 1,260 sq ft steam, and 290 to 2,015 sq ft hot water. Complete literature on above units furnished upon request 844 L. J. Mueller Furnace Co. Air Conditioning Systems and Furnaces Mueller Heaters For AH Fuels--All Purposes "The Most Complete Line in the Industry" Return Flue all-cast Fur nace. IS in. to 30 in. firepots, single and double firedoor styles. Available in round, galvanized or square, lacquered casings. Double Radiator all-cast Furnace. Seven sizes, 20 in. to 33 in. firepot. Vast heating surface. Lacquered, square casing, or round, galvanized iron. Mueller Steel Furnace. Riveted and welded. Extra heavy construction. Burns any fuel. Seven sizes, 20 in. to 34 in. drums. Square lacquered or round gal-. vanized casing. Gas Era cast iron Furnace. Sectional construction. A. G. A. input rating, 65,000 Btu per hour per section. Insulated, lacquered casing for fan cr gravity. Gas Era pressed steel sec tional Furnace. A. G. A. input rating 45,000 Btu per hour per section. Insu lated, lacquered casing for fan or gravity operation. Series C Gas Era Boiler, for steam, hot water or vapor heating or hot water storage. A. G. A. rating, 1,260 to 12,600 sq ft steam; 2,680 to 20,100 water. Nos. 80-A and 90-A Horizontal Tubular Heaters for large buildings. Furnished with steel jackets or for brick-setting. For coal, wood or oil burning. Capacities to 750,000 Btu per hour. Nos. 93, . 94 and 95 cast iron Horizontal Tubular Heaters are especially designed for schools, churches and similar large buildings. Capacities from 1,188,000: to 1,390,000 Btu per hour. ' Catalog on Mueller gravity and air conditioning registers and grilles available upon request 845 Air Conditioning Systems he Meyer Furnace Company PeoriaJllinois Manufacturers of Domestic Heating and Air Conditioning Units for Coal. Gas and Oil Burning Branches and Distributors Kansas City, Mo. Omaha, Neb. Green Bay, Wis. Pittsburgh, Pa. New Orleans, La. Detroit, Mich. St. Louis. Mo. San Francisco, Calif. Des Moines, Iowa Minneapolis, M.nn. The WEIR Conditioned-Air Unit for coal burning, built around the famous WEIR Steel Furnace, is a complete unit for con ditioning the air in the home during the heat ing season. Equipment includes automatic humidifier, renewable filter, centrifugal blower and automatic damper and blower controls. WEIR Conditioned A ir Unit WEIR Gravity Heater No. Grate Surface (Sq Ft) Ratio Htg. to Grate Surface Smoke Outlet Diam. On.) Gravity Circulation Casing Dimen. Rated Output Round Rect'lar At Reg. Pipe Area (In.) On.) (Btu.Hour) (Sq In.) Fan Circulation Casing Dimen. (In.) Air Rated Output Delivery at register (CFM) (Btu.Hot*') 621 1.26 624 1.78 628 2.32 640 3.08 633 3.82 636 4.74 540 6.25 544 7.60 41.2 33.9 29.2 25.4 22.7 19.4 19.3 18.5 9 10 10 10 (0 10 12 12 48 54,400 400 52 47x50 73.600 541 47x90 1200 54 50x52 94,100 692 50x99 1600 58 54x56 119,000 875 54x103 2000 65 56x64 138.000 1015 56x110 2300 67 56x66 160,000 1180 56x118 2700 64x114 5000 92,000 118,000 148,000 172,000 200,000 3i6!66o WEIR Oil Fired Air Conditioner The WEIR Oil-Fired Air Conditioner does a complete job of winter air conditioning. Designed for oil fuel and forced circu lation. Features include quiet operation, dependability, safety, long life, modern appearance and high efficiency. The MEYER Gas-Fired Air Conditioner provides complete winter air conditioning. Modern in appearance, compact and efficient with heavy gauge, welded steel, gas-tight heating section. Equipment includes automatic humidifier, renewable filters, centrifugal blower and fully automatic controls.. No. Input Output . Vent Burner Bonnet (Btu/Hour) (Btu/Hour) L>tam. (In;) Dimensions Air Delivery W. L. H. V* In.S.P. (In.) (In.) (In.) (CFM) Size (HP) MEYER Gas Fired Air Conditioner MEYER Gravity Gas Furnace 125-A 175-A 225-A 200,000 275.000 350,000 WEIR Oil-Fired Air Conditioner 150,000 205,000 265,000 v 7 48 65 48 56 65 48 63 65 48 1700 2300 3000 MEYER Gas-Fired Air Conditioner B-t B-I'A B-2 B-3 B-4 B-5 90,000 135,000 180,000 270,000 360,000 450,000, 67,500 101,250 135,000 202,500 270,000 337,500 4 20 53 42 1000 5 27 60 44 1500 7 40 53 42 2000 6 60 53 42 3000 9 80 53 42 .. 4000 10 100 53 42 5000 1/6 1/4 1/3 1/2 3/4 3/4 MEYER Gravity Gas Furnace ' C-100 C-120 C-150 100,000 120.000 150,000 75,000 90,000 112,500 5 6 6 38 42 42 38 42 42 60 67 67 Complete descriptive literature, including data on Bummer cooling, upon request The MEYER Gravity Gas Furnace--Efficient--Economical --All steel, welded heating section--large heating surface-- A.G.A. approval. 846 i Air Conditioning and Automatic Heating Systems Norge Division Borg-Warner Corporation 606-670 E. Woodbridge Street, Detroit, Michigan Norge Fine-Air Conditioning Furnace Unit Newest and most revolutionary Norge development, is the Norge Fine-Air Fur nace. It actually warms, humidifies, filters, circulates, purifies the air in every room in the house.. Moreover, it provides plenty of hot water during the winter months, with simple adjustment to prevent steam. May easily be converted for cool ing and de-humidifying during summer months. And all these advantages cost no more in operating expense than the average ordinary heating system. The Fine-Air' Furnace is suitable for new homes, or may be used to replace present warm air heating equipment. Complete Winter Air Conditioning. A balanced matched unit with ex ceptionally high fuel efficiency. Fully automatic with oil as fuel. 1500-2200 cfm adjustable air delivery. Effective radiation surface--104 sq ft. Hot gas travel--35 lineal feet. Bonnet output up to 200,000 Btu per hour. . Very fast heat delivery. Quick response to temperature controls. Fuel efficiencies over 80 per cent. Automatic air filter control. Correct humidification. Adjustable high output domestic water heater. . Oversize deep-blade fan with reserve power simplifies air duct arrangement. Height................................. 62in. Width..................................40in. Length........... 68 in. Includes Norge Whirlator Burner as standard equip ment -- manufactured by Norge Heating and' Con ditioning Division of BorgWarner Corporation, Detroit, Mich. See also Pages 830 and 892 847 Air Conditioning and Automatic Heating Systems Williams Oil-O-Matic Heating Corporation Manufacturers of Air Conditioning Equipment Bloomington, Illinois Service to Architects and Builders Chicago, III., 641 N. Michigan Avenue New York, N. Y.,1231 Graybar Building For Williams Oil-O-Matic Oil Burner Equipment and Ice-O-Maiic Refrigeration Equipment, see File Index Air-O-Matic Combines Heating and Cooling in One Air-Conditioning System The Williams Oil-O-Matic Heating Corporation has developed an outstanding year 'round air conditioning system known as "Air-O-Matic." Low pressure steam, which is usually provided by an Oil-O- Matic operated boiler unit, is supplied directly to a copper finned heating coil within the central air distributing unit for heating service, which can be supplemented by direct radiation if desired. Proper provision for the addition of moisture is provided for winter heating service. This same low pressure steam, through an especially developed absorption re frigeration unit, provides the proper degree of temperature and humidity reduction for summer comfort. A change from winter to summer operation can be effected almost instantaneously by means of a master control located in a suitable, convenient place. The Williams Low Pressure Steam Absorption Type Unit, the outstanding feature of Air-O-Matic, has been especially developed to meet the particular require ments of air conditioning through years of research in the Williams' laboratories. It affords adequate comfort cooling facilities with unusual advantages of economical operation, mechanical simplicity, com pactness and freedom from fire and toxicity hazards. Both the solvent and refrigerant are newly developed chemicals and are essentially non-toxic, non-inflam mable, non-corrosive to the common metals and chemically stable under all operating conditions. The steam requirements for one ton of refrigeration are 19 lb. (18,200 B.t.u.'s) per hour at a pressure ofJO to 12 lb. gauge. The electrical power requirements for one ton of refrigeration are 75 to 100 watt hours per hour. `Note.--Any low pressure steam boiler of proper capacity may be used to generate the required steam. A Wil liams Oil-O-Matic Boiler-Burner Unit or other types of automatic heating systems may be used to maintain the necessary steam pressure automatically. The only metal to metal contact of moving parts within the refrigeration unit is between the seal face and seal seat of the solution circulating pump. This seal face operates in a bath of oil, thereby assuring proper lubrication. The maximum pres sure against this seal face is only 45 lb. In normal operation the pressure on the low side of the unit is between 8 in. and 2 in. of vacuum and the pressure on the high side is between 22 and 28 lb. gauge. The steam requirements remain at 19 lb. per ton hour at high or lower cooling water or evaporator temperatures within a reasonable range. These new absorption refrigeration units are remarkably compact. For example, the 15-ton unit is 44 in. long, 44 in. wide, and 65 in. high, and the 25-ton unit is 65 in. long, 65 in. wide and 65 in. high. There are now available seven different sized units ranging in capacity from 6 to 25 tons. The cooling coils of the dry expansion, type and the expansion valve are designed for the unique characteristics of the refrigerant. Low Steam and Power Requirements The low power requirements make pos sible the use of single phase current in the smaller size installation, thereby saving the expense of providing 3-phase current. For all sizes of machines any low pressure steam boiler of the proper capacity may serve to generate the required steam. See also Page 89S 848 Air Control Dampers The Young Ventilating Company 2700 Woodland Avenue, Cleveland, Ohio CONTRACTORS - ENGINEERS - MANUFACTURERS YOUNG REGULATOR A Convenient Control of Air Conditioning and Ventilation The Young Regulator controls the volume of air flow through a duct by opening and closing a volume damper with which it is connected by a % in. square rod. Indicator and dial show accurately position of damper in duct. For service in schools, hospital, residences, offices, banks and public buildings, the operator in charge of air conditioning and ventilating finds it easy, with this device, to establish and main tain the proper volume of air, free from interference or meddling. The Young Regulator is simple to install, with direct con nection to the damper. It is made of rust-resisting metal and presents a neat appearance. For Locking a Volume Damper in a Permanent Position . With the handy wrench the damper is readily set to admit the desired amount of tempered air, and locked in that position, making it tamper proof. The device for adjusting is the outer most nut, or head with eight sides, turned by wrench. . Behind the adjusting nut is a set nut with ten sides, of larger diameter, which, with a turn of the wrench, will lock the regulator at any desired position, or release it. This nut is difficult of access by any ordinary wrench. REGULATOR Diagram Showing Vent and Supply Ducts, in which Damper Controls are Installed 849 Air Filters and Cleaners American AirFilterCompany Inc. 1st Street and Central Avenue, Louisville, Ky. Representatives in Principal Cities Dust Engineering--Dust Engineering is that branch of applied science which deals with the origin, nature and characteristics of the small solid air-borne particles called "dust," and the development of methods, processes and apparatus for its control or elimination. . The American Air Filter Company, Inc., has had an important part in advancing the science of Dust Engineer ing. The efforts of its Re search and Engineering Staff for the past twelve years have been devoted exclusively to the study of dust problems and the development of a complete line of air cleaning equipment for modern air conditioning, building venti lation and the control of pro cess dust in industry. American Air Filter pro ducts, therefore, not only embody the knowledge ac cumulated from years of con stant research and the ex perience gained from design ing, building and applying thousands of air filters, but are backed by ample technical and financial resources to in sure their outstanding posi tion in the Dust Engineering field. Products--American Air Filters are available for every condition, with operating characteristics and efficiencies to suit specific problems. In Data Section under "Air Cleaners." Air filters are generally used for the removal of dust, dirt, bacteria and other foreign matter from the air and are applied to general ventilation, modern air conditioning, pro cess dust control; for air com pressors and Diesel Engines; mill motors, turbo-generators and other electrical applica tions; and for air or gas under pressure to remove entrained oil, moisture and dirt. Air Filters in Air Con ditioning--Filtered air is today recognized as essential in modern air conditioning. There are other important factors which contribute to our comfort such as tempera ture, air movement and humidity, but science today emphasizes the prime neces sity of pure air for health and efficiency. Throway Air Filler Air cleaners have, of course, always been considered an integral part of large central systems. These are usually of the fully automatic. type such as the Multi-Panel'filter, illustrated in the accompany ing photograph. There are now available to manufacturers of unit air con ditioners moderate priced unit filters, such as the Re-Nu filter, the Drifilter and the Throway filter, illustrated herewith. The Re-Nu filter is an general, there are two dis tinct types based upon the "viscous film" and "dry mat" principles. Each entirely new departure in air filter construction. It consists of' a permanent metal frame provided with type is made in several styles which differ in method of operation, servicing, space required and initial cost to meet the various conditions en countered in air cleaning problems. A discussion of various filter types will be found in the Technical Standard Vitcout Unit Filter S50 American Air Filter Co., Inc. Air Fillers and Cleaners a removable cover and renewable filter pad The cover is easily removed without the use of tools, and filter pad can be lifted out and replaced with a new one at very small expense in less than a minute's time. The Drifilter consists of the Airmat filtering media mounted on a supporting member and arranged in saw-tooth fashion, as illustrated. The filter media is reason able in price and can be easily replaced when desired. . The Throway filter, as the name implies, is an inexpensively constructed unit de signed to be discarded after it has served Standard Viscous Unit--The Ameri its maximum period of usefulness and re can Unit Air Filter incorporates the time placed with a new filter unit. The filter tested unit principle of construction. Each pad is enclosed in a perforated cardboard unit consists of a standard steel frame and container which makes it possible to interchangeable cell equipped with auto dispose of the dirty filter by burning it in a matic latches to facilitate removal for furnace or incinerator. cleaning and recharging. There is probably no single item which Airmat Filter Dry Type--The filter costs as little and may mean as much in the ing media in this type is the Airmat sheet, design of an air conditioner as air filtra a dry filter mat composed of thin sheets of tion. These units are furnished in any gauzy, cellulose tissue. The Airmat sheets dimensions or shapes desired. They are are supported in screen pockets mounted usually built in units handling 400 c.f.m. in a unit frame of box-like construction. and from 2 in. to 4 in. thick. They are These unit frames can be set up to meet usually made in the following sizes-- any capacity requirement or space con 20 x 20 in., 16 x 25 in. and 16 x 20 in. dition. The Airmat sheets are renewable High cleaning efficiencies can be secured, --their life depending on the dust con with a resistance to air flow ranging from dition and hours of daily service. in. to % in. water gauge. Airmat filters are used both for air con . Automatic Self-Cleaning Air Filters ditioning and industrial air conditioning. --The American line of automatic air In the latter field they are particularly well filters is among the most complete that adapted for the recovery of valuable dusts has ever been offered, the most popular and for abating the dust nuisance which _ types being Multi-Panel, Horizontal and confronts so many industrial plants. . Phoenix Filters. Our standard data books and catalogues All types are furnished for either con are to be found in most engineering files tinuous or intermittent service and are or libraries. We will be glad to furnish available in sizes and set-ups suitable to : full data to engineers or manufacturers any desired capacity or space condition. interested in this subject. Voricm* Type* of Unii Air Fitter* for Air Condttioning Wort 851 Air Filters and Cleaners Coppus Engineering Corporation 339 Park Avenue, Worcester, Mass. MANUFACTURERS OF AIR FILTERS, STEAM TUR BINES, FORCED DRAFT BLOWERS, COOLING FANS Coppus Unit Filter Coppus Unit Filter--The Coppus Unit Filter is of the dry type using a removable filter glove of all-wool felt and sup ported by a rigid, welded distender frame which is adjustable so that after assembly the filter glove may be stretched and held tautly inside of the filter casing, giving the pockets a tapered shape so essential for an even air flow. All metallic parts are riist-proofed (Bonderized, Cadmium Plated),' and Duco painted. Specifications Normal Rating: 800 cfm. Resistance when clean: .2 in. W.G. Dust Arrestance (cleaning efficiency): 99.61 per cent (Tested in accordance with A.S.H.V.E. Standard Code for Testing and Rating Air Cleaning Devices Used in General Ventilation Work). . Dimensions:. 20 in. by 20 in. by 6H in Weight per unit: 25 lbs. Outstanding Advantages 1. It has an exceptionally high dust arrestance. Cleaning Fitter Ele ments with Portable Vacuum Cleaner 2. It maintains a high dust arrestance even under diverse conditions of neglect. 3. Its operation is not impaired by atmospheric conditions. 4. It is a Medium Air Resistance Type (Class C) according to the A.S.H.V.E. Code for Air Cleaning Devices. 5. It is easily and quickly cleaned without removing the filter element. 6. Its cost of upkeep is very low because the permanent filter element is reconditioned periodically with a vacuum cleaner. 7. It combines scientific knowledge and.practical engineering methods with highest quality of material and workmanship. Coppus Dry-Matic Filter Automatic Self Cleaning DryType Air Filter --It uses a spe cially woven cotton textile as. filter medium arranged in the shape of an endless belt in zig zag fashion over rolls. The hori zontal pockets have a tapered shape, thus securing an. even rate of air flow over the. whole effective filter area. At pre determined intervals the filter curtain is automatically -moved by a small geared motor over the rolls, thus passing over a suction nozzle. For certain types of dust the filter is also equipped with a beater which, at predetermined intervals, auto matically reconditions the filter curtain. The cleaning and reconditioning operation takes place while the ventilating system is in operation. Built in capacities from 2000 cfm up. Coppus Window Air Filter It supplies a continuous flow of filtered air, is extremely quiet in operation, keeps out street noises, eliminates dirt and dust including invisible particles, and last, but not least, is very effective against rag weed pollen [ in concentrations ______ ___ commonly found FL 1 Wira in the hay fever M I! BHBfiMPseason. Its use ;s recommended * for offices, homes and hospitals. Air Filters for Compressors and In ternal Combustion Engines. Steam Turbines, Horizontal and Vertical, 1 to 150 Hp. Forced Draft Blowers. : Portable and Cooling Ventilating Fans. ' 852 Air Filters Independent Air Filter Co. 215 West Ohio Street, Chicago "DOUBLE DUTY" An Air Cleaner That Cleans Itself--and Never Clogs Three Section Group, 9 ft. S in. high bp 9 ft. 0 in. unde, capacity 30,000 c'f.m. "Double Duty ' filters made in capacities from 3000 to 600,000 c.f.m. This type especially adapted for large installations, where automatic oper ation and unvarying air flow are im portant factors. The filtering principle is that of true impingement on viscous coated metal surfaces. Endless filter curtain-composed of die stamped steel plates, heavily indented, and disposed in overlapping form. Acute deflections of individual fins, constantly coated with heavy oil, result in high cleaning efficiency. Entirely self-cleaning, re-, gardless of dust content of air. Self draining design of curtain plates elimi nates all danger of oil entrainment. "KOMPAK" A Low Velocity, Dry. Fabric Air Filter--With Renewable Medium Cross-section throughfitter. Sludge is removed at in tervals oftwo to six months. Oil consumption negligible --never changed; merely replenished For general ventilation and industrial air clean ing. Filtering principle that of straining air through fabric material at low velocity. Standard filter medium high grade, fluffy cotton material, with high cleaning efficiency and remarkable dust hold Note easy method of detaching unit from frame. Improved style locking device clamps felt seal firmly against main frame ing capacity. Each unit contains 27 sq. ft. of filter medium, which, at normal rating of 600 c.f.m., results in velocity of 22)4 f-p.ni. through Method of Servicing Entire - operation--unloading, re filling and replacing--consumes at most S minutes per unit. Useful life of fitter medium varies from three to six months, depending on conditions medium. Initial resistance 0.15 in. W. G. Frame installation. No pad container necessary. Only the pad is throum away HAIR PAD A High Grade, Low Cost Air Filter Filter medium composed of Keratin fibre (animal hair) thoroughly sterilized, making it sanitary and odorless. Fabricated with progressive density into a self-supporting pad of great resiliency. Oil treated to increase cleaning efficiency and dust holding capacity. For ventilating and air conditioning systems frames are made standard size 20 in. x 20 in. x 4)4 in. (overall) rated at 800 c.f.m. per unit. Initial resistance with pads in double formation 0.12 W. G. 853 For warm air heating systems and air condition ing units pads are made in three standard sizes, SO x SO, 16 x S5 and 16 x SO. Special sizes, any shape, cut to order Air Filters INDUSTRIAL MATERIALS DIVISION Owens-Illinois Glass Company MANUFACTURERS OF DUSTOP AIR FILTERS Newark, Ohio The Original Replacement Type "Dustop"--the Glass Wool Air Filter of High Efficiency and Low Cost for Use in All Types of Ventilating Systems or Wherever Air is Mechanically Circulated Dustop--The Owens-Illinois fibrous glass air filter is the modern answer to the demand for low cost, efficient air filtration. Dustop filters can be assembled in any required number of units to clean air in every type of commercial and industrial building. Dustop maintains a high efficiency in removing dust, dirt, lint, pollen, bacteria and other harmful impurities from circulated air. Dustop is simple in design and operation--progressively packed--ready for use--easily disposed of when dirty--3 to 6 months between changes--efficient--odorless--light in weight. Because of its many outstanding features Dustop is one of the most desirable filters on the market. rmta mM 9! m mmmw/ Hiwt m a?ur-JjK s w:, H m 19BB Overall Site of Frame Unit (One complete " b" or 800 c.f.m.) Width, tO tn. Height, tO in. Depth, 4% in. Uses standard 20 x tO x t Dustop Filter FILTERS INSTALLED in TWO Arrangements The "L" Type for Plane Bank Arrangement Rating Capacity per unit, 800 c.f.m. Maximum velocity, 300 f.p.m. . Resistance at rated capacity (two filters in tandem), Clean, .25 in. w.g.; Dirty, .38 in. w.g. ' The "V" Type for Limited Space Rating \ Capacity per unit, 1000 c.f.m. Maximum velocity, 300 f.p.m. . Resistance at rated capacity (two filters in tandem), Clean, .25 in. w.g.; Dirty, .38 in. w.g. - ` Overall Hire of Frame Unit <One complete "V" or 2000 c.f.m.) . Width, 80 in. Height, tO in. Depth; 7 in. Uses standard tO z tS x t Dustop Filler FRAME CONSTRUCTION FOR ANY C.F.M. CAPACITY ' Sold by fan, blower, unit and air conditioning manu facturers and our authorized distributors--everywhere. ' Replacements--Stocked by our authorized dis tributors in all trading centers. - 854 Air Filters Somers Air Filter Sales Co. 7310 Woodward, Detroit, Mich. SOMERS "HAIR GLASS" FILTER (Patented) The Somers Filter Mat requires no adhesive material to catch the dust particles of the air stream in passing between the fibers. Its construction is such that it forms an effective dust bar rier that is highly efficient, the range depending on the type of pack, air stream velocity and the character of the dust. Cleaning the filter is easy and it is a most desirable construction for use where oper ating velocities or temperatures are re latively high or where a high degree of air purity must be secured. "Hair Glass" in this form reacts with practically none of the chemical elements carried in the air stream. It is easy to maintain in proper functioning condition as "Hair Glass" neither rots nor dis integrates in service. "Hair Glass" is pliable and tough, it is both odorless and non-absorptive. Consequently, the user has wide latitude in his methods of hand ling and cleaning the unit. The Somers Filter does not have to be replaced as soon as it fills up with dust. The entire pack may be washed with hot water, cold water, or chemical solvents and as often as necessary, without in the least impairing its operating efficiency. Standard frames and mesh are galvan ized or alloy although other materials can be furnished if required. The Somers filter may be assembled in different thicknesses; > No. 1 Pack--The thinnest, is used where the resistance must be kept low. It is usually employed for domestic applica tions, recirculating systems and gravity flow. No. 2 Pack--Is generally used for all commercial and industrial applications. It will arrest liquid particles in the air stream. Filter units can be made to exact dimensions. Bank holding frames can be supplied. Give outside dimensions. l k. <-Ju K Ul 1S 8 FILTER FRAME DIMENSIONS K $ Ul K o K 9 & s2O AREA IN INCHES 8 \5o i ft: 9 fS. < Uj Cfc Ul t b Q C <- FILTER ONLY W E IG H T IN POUNDS a! K Ul S C A SO v 20 H 400 /:/ a 16 S3 0* 40C t.t rr s! X Y ip XY 1:1 J SO K 20 /% 400 LZU K 16 c 25 /% 400 L2:l sQ X y e<i XV LS:I R d X p` Y & XY Z:i gS Ul X y 2% XY 25:1 87 O X Y XY 3 -1 UX y 3% XY 3.5:1 V X ,i, Y XY 4U w X >: X Y A XY 4SJ 400 3.25 2 400 3.25 * Z XY .OOQXY d 2 460 SZS 460 SZS 1 1 15XY .0/6 XY t 2 XY ozoxr 1 1ISAY 023*y 1 3XY 025XY 15XY \OZ7XY i 4XY .OZ9Kf i 45XY }30XT t STA T E *X' AND `Y * DIMENSIONS IN ORDER GIVEN. VEE RIDGES RUN VERTICALLY, -- PARALLEL TO 'X' DIMENSION. 855 || ON 3 6 0 3 1 3 1 Air Filters and Cleaners Staynew Filter Corporation Air Filters for Buildings and Mechanical Equipment 6 Leighton Avenue, Rochester, N. Y. Products-- Protectomotor Dry Type Positive Filters for removing dust, dirt and foreign matter from small or large volumes of air at atmospheric or at higher or lower pressures. Made in various types and sizes for buildings, windows, oxygen chamber in hospitals, furnaces, pipe lines, air compressors, diesel engines, blowers, motors, pneumatic systems, air brakes, etc. Operation-- The efficiency of Protectomotor Air Filters is exceptionally high due to their large filtering sur face within a relatively small space. The intake air currents move parallel to the filtering surface at very low velocity, so that dust and dirt are not packed on to the felt, but remain in a loose and piorous condition, which permits air to pass through the accumulated dust and dirt quite as readily as through the felt itself. Dust and dirt do not enter pores of the extremely fine texture felt. Efficiency-- Due to the low air velocity and the fine texture of the felt, practically complete removal of dust is obtained. An exceptionally high efficiency is maintained, even on fine air-floated dust. Efficiency is not greatly affected by continuous service, nor . by any change in volume of air passed. . Pressure Drop-- Resistance to the flow of air is less than in. water gauge when operated' at rated capacity. Less . pressure drop, when required, may be obtained by using an oversize filter. Gleaning-- Under ordinary conditions filters operate from six months to a year Without atten tion. A special cleaning device enables the material collected on the filtering surface to -be very quickly and com pletely removed by compressed air or vacuum cleaner. The material may be reclaimed, if valuable, without con tamination, since no sticky or adhesive oils are used. No spare parts or cleaning tanks' are necessary. Less than two minutes' time, per 1000 cu..ft. per minute of air capacity, required for cleaning. Filters may be cleaned while in operation, without removing filtering units. Proledotent Window Ventilator One filter ccU removed, exposing one ofthe fans and motors Application-- All filter units or filter assemblies are complete in weatherproof housing, ready f to attach to air intake pipe for applica tion to engines, compressors, etc. For building ventilation, equipment is easily " adapted to space available. . Write for Catalog. Diagonal view showing adjustable ends storm hood, filler , and deflector plate. Note the large, active surface 856: Boiler (Cleanser and Leak. Seal) The Vinco Company, Inc. 305 .East 45th Street New York, N. Y. VINCO BOILER CLEANSER Vinco for Old Systems A positively harmless insol uble powder cleaner for new, remodeled and old heating sys- terns. A unique, scientifically processed com* pound on a special formula not to be con fused with other powder boiler cleaners. Adopted. By *American Radiator Co. *Burnham Boiler Corp. Hoffman Specialty Co. National Radiator Corp. Petroleum Heat & Power Co. Sarco Co. Titusville Iron Works Co. *United States Radiator Corp. and many others Vinco Distributors What Vinco Does Vinco permanently removes oil, grease, scale, rust and dirt from the internal sur faces and from the boiler water without the . ' labor of blowing boilers over the top. By this thorough cleansing Vinco stops foaming, priming, surging, and slow steaming. How Vinco Works Each minute grain of Vinco powder absorbs several times its own weight of oil, rust and dirt. These larger grains of absorbed impurities then settle and are blown through the bottom, according to directions on each can. Vinco Specifications for New and Remodeled Steam and Vapor Systems Cleaning the System -- Upon completion of the installation, the contractor shall clean the system by the Vinco method to remove oil, grease, rust and dirt from the boiler using, t_____ lb. of Vinco, in exact accordance with manufacturer's directions. . This compound must remain in the boiler for at least 10 days of normal operation--not longer than 60 days. At the end of this period,' boiler must be thoroughly drained and flashed before refilling with clean water. Annual cleaning of the old heating system adds years of life to the boiler, prevents rust de terioration and saves much fuel and fire atten dance. Only half quantities given in specification table. Our Three-Fold Guarantee 1. Vinco contains no potash, lye, soda of any kind, oil, acid, or other harmful ingredients. Leading boiler. manu facturers have placed lags on their boilers advising against use of acids or alkalies. 2. Purchase price is refunded if results are not as claimed when Vinco has been used according to directions. 3. Your time, money and comfort are further safeguarded by Our Free Laboratory Service Saves thousands of dollars by analyzing the boiler water before making needless mechanical changes. If desired, the boiler water is again examined after the Vinco treatment is completed, and "certified chemically correct" for boiler operation. (Write (or details.) VINCO SUPERFINE LIQUID BOILER SEAL A different liquid leak seal. Unique in that it does not induce priming and foaming. It has no unpleasant smell. Makes speedy and permanent repairs of boiler and heating system leaks. Fine to tighten up new jobs. Directions simple. Quantities pounds of Vinco to be used in accordance with the following schedule. For systems having actual inafalM radiation of: Up to 350 sq.ft....________ ____________________ 3 1b 351 " 600" " 5" 601 " 1100"" __________________ 8 " 1101 ** 1400 " " 1401 " 1800" " ....__ _ io " 13 " 1801 M 2100" " _________15 " 2101 " 2700" " ,,18 " 2701 " 3100 " " _ __ 20 " 3101 " 3700." " ox 3701 " 4200 " " __________;_____ _26 " 4201 " 4600 " "........ : ,,_ *'*" 28 " .4601 " 5000 " " ............. ' ........... " Above 5000 sq ft use an additional pound of Vinco for each additional 300 sq ft of installed radiation. 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 Seal to each 6 sq ft grate area. VINCO SOOT-OFF Destroys soot from coal, oil or gas burning heating equipment. Easier, cleaner and quicker than brushing. Makes short work of jobs too hard for brush or scraper. Vinco Specifications for Hot Water Systems Cleaning'the System--Same as above but only one-half quantities in specification table required. Cleans fire pot, flues and chimney in one simple operation. Non-explosive, thor oughly safe. 857 Boiler (Feeders) M-DONNELL & MILLER Manufacturers of McDONNELL Boiler Water Level CONTROLS General offices: Wrigley Building, Chicago, 111. "Doing one\~~ything well" BASIC ADVANTAGES: McDonnell Boiler Water Level Controls protect low pressure steam boilers from the damage and shut-downs caused by low water. In connection with automatically fired boilers they "make the boiler water level as automatic as the firing." (Recom mended by A.S.M.E: Boiler Code, Under writer's Laboratories, Boiler Insurance Companies--Required by ordinances in over 20 cities.) (Table 1) For Hand Fired Jobs Boiler Size in Square Feet Up to 5.000 Above 5.000 Any Size Steam Pressure Product to Use Under 25 lb Under 25 lb 25 lb to 75 lb No. 47 Water Feeder No. 51 Water Feeder No. 53 Water Feeder FEATURES OF CONSTRUCTION: In all McDonnell Boiler Water Feeders the feed valve and all important working parts are iso lated from the heat of the float chamber. As a result, scale and lime does not form at the feed valve. (Covered by Patent No. 1,934,486.) No. 47 Water No. 47-S Combined Feeder and Cut-off with Quick - Hook - Up Fea ture. AUo furnished Feeder and the without cut-off switch No. 60-B Low (No. 47) Water Cut-off have "Quick- Hook-Up Fea ture" which per mits installation in water glass tap pings and assures correct reproduc tion of the water level. (Covered by Patent No. 51 feeder. AUo 1 007 7o c \ ., fnmuhed with cutoff ,, twitch (No. ll- AIL McDonnell Water Feeders have stainless steel valves, straight thrust valve action, double sylphon (packless) construction, large, easily removed integral strainer, and many other exclusive features. All cut-offs and feeder-cut-off combinations are equipped with the effective McDonnell quick-acting wiping-contact switch with low water alarm terminals as standard To determine type of equipment suited to specific conditions, consult the tables: (Table 2) For Automatic Jobs Where Completely Automatic Control is Desired* Boiler Size in Square Feet Up to 5.000 Above 5.000 Any Size Steam Pressure Products to Use Under 25 tb Under 25 lb 25 lb to'75 lb No. 47-2 Combined Water Feeder and Low Water Cut-off. No. 51-2 Combined Water Feeder and Low Water Cut-off. No. 53-2 Combined Water Feeder and Cut-off. (Table 3) For Automatic Jobs Where Only a Low Water Cut-off is Desired Boiler Size in Square Feet Any Size \ Any Size ' Steam Pressure Product to Use Under 25 lb 25 lb to 100 lb No. 60-A--for 1 in. equalizing pipe hook-up. No. 60-B with quick hook-up feature for all round boilers and small sectional boilers. No. 32 R P. (Also used as a pump con trol on boilers of 1004b maximum). *The combined feeders and cut-offs (Nos. 47-2, 51-2 and 53-2) offer both pro tection and the convenience of completely automatic operation for oil or stoker-fired boilers. If, however, price is the dominant factor, the No. 60-A, No. 60-B, or No. 32-H. P. Cut-offs will dependably interrupt the current to the firing means when the water level falls to the danger point." 858 . ' Boiler (Feeders) MCDONNELL & MILLER Manufacturers of McDONNELL Boiler Water Level CONTROLS General offices: Wrigley Building, Chicago, 111. "Doing ane\^ything well" TYPICAL SPECIFICATIONS FOR WATER FEEDER OR COMBINED FEEDER AND CUT-OFF Contractor to furnish and install complete in every essential detail for each boiler unit, Automatic Boiler Water Feeder--and Low Water Cut-off (if automatically fired)--equipment as manufactured by McDonnell & Miller, Wrigley Building, Chicago. Boiler Water Feeder to be (Insert**) of the manufacturer's most improved design, with all working parts isolated from the steam and hot water zone by packless sylphon construction. Float power to be multiplied through a lever age mechanism which contains a self centering roller directly above the valve stem. All bearing points, pivots, and levers, to be outside of the steam and water zone. Valve cone and seat to be stainless steel, removable and renew able. A strainer to be incorporated in the design- and to have a solderless basket mounted on a flange for easy removal. Feeder to be installed com plete with all piping, valves, fittings, and specialties, as indicated by descrip tive diagram in the manufacturer's construction bulletin. Upon completion of the installation, the contractor to place this automatic equipment in successful operation, sub ject to acceptance and approval of the architect's...........................engineer. --If job is hand fired, insert: "No. 47," "No. 51," or "No. 53." (See Table 1). --If job is automatically fired, insert: "No. 47-2," "No. 51-2." or "No. 53-2." (See Table 2). When combined units No. 47-2, No. 51-2, or No. 53-2 are specified, add the following paragraph: "Make electrical connections for low water switch; to control fuel supply equip ment, so that the fuel is automatically shut off by the low boiler-water control. Control wiring to be of flexible armored cable. All wiring to meet the require ments of the City Electrical Inspection Department and the National Board of Fire Underwriters." TYPICAL SPECIFICATIONS FOR LOW WATER FUEL CUT-OFF Furnish and install on each boiler,' in accordance with the manufacturer's instructions a McDonnell & Miller No. (insert!) Low Water Fuel Cut-off, to be of packless construction, with all working parts outside the steam and water zone. Switch to have snap, wiping-action contacts. Control wiring to be of .flexible armored cable. All wiring to meet the requirements of the City Electrical Inspection Department and the National Board of Fire Under writers. tlnsert at this point: "No. 60-A," "No. 60-B," or "No. 32-H.P." as indicated by service con ditions per Table 3. Ask for information covering special conditions such as application of water level control to higher pressure boilers in which steam pressure is in excess of water pressure. Our engineering department is qualified by widely diversified experience to solve any special problems which may arise involving water or liquid level fluctuation. The Mc Donnell catalog contains complete descrip tions, in stallation instruc tions, di mensions, wiring dia grams, ca pacity curves, ana other valu able data. No. 60-B Loin Water Cutoff with Qwieh- Hook-Up Feature. AUo furnished with out Quick-Book-Up Parts for instal lation with l-inch equalizing pipe. (No. 60-A) . Boiler (Water Treatment) Aquatic Chemical & Metallurgical Engineers 118 East 28th Street New York, N. Y. An Organization of Water Treatment Experts Manufacturers of Scientific Products for Eliminating LAND (y _ SERVICE Rust, Scale, Foaming and Related Water Troubles DEVELOPMENT--A-C-M-E laboratories, having surveyed many different waters and types of heating installations, are bringing to your attention a series of practical and accurate water treatments for house heating boilers. Long technical experience with water problems in the marine and stationary high pressure boiler field, together with careful diagnosis and follow-up, enables us to bring the low pressure boiler plant within our scientific control. . TREATMENTS AND THEIR ACTION--Our materials are distributed in con venient quart containers ready for use. They act upon accumulated rust, scale and oils at a proper slow rate to completely disintegrate and loosen them, without plugging and stopping steam and water flow--by holding the resulting sludge in suspension until blown out. The treatments acting thru their colloidal, chemical and electro-chemical pro perties prevent the further formation of rust and scale, and stop frothing. RESULTS--The heat retarding action of scale, rust and oil is eliminated; accumula tions of mud and core-sand are swept from the system; foaming and dirty water pre vented and corrosion overcome. As a result, steaming is easier, a surprizingly large amount of fuel is saved, repairs and replacements are minimized and the entire heating system made more efficient. Because heating surfaces are actually cleaned, heat transfer is quicker. Moreover, deposits of rust are removed from such places as hot water heating units, valves and other auxiliaries. Continued treatment prevents further accumulations. Since corrosion is arrested, boilers do not rust and leak. UNIQUENESS OF A-G-M-E SERVICE AND TREATMENTS--For the first time, instead of buying a single preparation for all boilers and all troubles, you can purchase a different and scientifically prepared product depending upon whether yours is a cast-iron boiler or steel boiler, and whether it is coal, oil or gas-fired. Ask for No. 1L.P. folder. Quantities Required for one complete cleaning (two treatments) of house heating steam boilers: Cast-Iron: Coal or Oil-Fired--For each 6 sq. ft. or less of grate area, use two cans. Steel: Coal or Oil-Fired--For each 150 sq. ft. or less of boiler heating surface, use two cans. All Gas-Fired Steam Boilers--Two cans for the first and second 2000 sq. ft. of steam radiation, and - two cans for each additional 1500 sq. ft. thereafter. -. Hot Water Heating--For each 2500 sq. ft. or less of hot water radiation, two cans " Gas-Fired Treatment.'' Above Quantities are based on actual extensive field experience under average conditions. Our labora- ' lories will be glad to advise in unusual cases. AIR CONDITIONING SYSTEMS, SPRAY TOWERS AND WATER SERVICE LINES can. also be saved from the corrosive and destructive action of water and the impurities it collects. Recommendation without charge. Information upon request. RECOMMENDED AND USED BV LEADING HEATING AND VENTILATING ENGINEERS Scale which acts as insula tion can be re moved safely. Corrosion deteriorates e q u ip me n t quickly. Arrest it. promptly! Users are Impressed by Positive Results . 860 Boilers, Cast-Iron American Radiator Company 40 West 40th Street, New York, N. Y. Division of AMF.RICAN RADIATOR & STANDARD SANITARY CORPORATION Products for Every Heating Requirement On Automatic Heating MERICAN Radiator Company, the An important feature of the boilers and A world's largest manufacturer of the radiators listed here is that they are all heating equipment, includes in its cast-iron--the metal that scientific re line every product necessary for complesteearch and tests indicate is best for heating automatic heating, excepting oil burners purposes. Especially for automatic heating ' and mechanical stokers. This includes not --which is in most cases intermittent-- only boilers specially designed for oil, gas cast-iron radiators have advantages pos or coal, but radiators and controls as well; sessed by no other. They will stand more and such accessories to the complete job as than the normal abuse of installation and radiator enclosures, vents and valves, cop use without damage, and have the ability per pipe and fittings, time and limit switch to hold heat longer between periods of firing, es, and equipment for domestic hot water. and are easier to keep clean. The use of this family of products On the following pages are shown a few assures you undivided responsibility for of the products of American Radiator the satisfactory performance of the com Company. For detailed specifications or ` plete job. All of them are backed by the same dependability, the same experience, the same reputation for performance . . . and the name that for more than 43 years information on any of them, or on any other equipment for heating, see the Ideal Fitter, or write to American Radiator has stood for quality in heating--American Company, 40 West 40th Street, New Radiator. York, N. Y. BOILERS for automatic heating with every fuel No. 12 OIL BURNING No. 21 AUTOMATIC No. 11 OIL BURNING BOILER COAL-FIRED BOILER BOILER A deluxe model, exclu- sively for oil burning. De- signed with the cooperation of the technical committee of the American.Oil Burner Association. Jacket con- cealing Burner and controls can be furnished. - ' Designed especially for use with mechanical stokers and recommended by leadjng stoker unit manufac- turers, the No. 21 Boiler assures the best in coal fired automatic heat. See also Page 801 One of the first and finest exclusively oil burning, boilers for the small home, Equipment includes con- trols for complete auto matic requirements, ' _ .. P^MAKE IT AN "ALL AMERICAN" JOB! , 861 V American Radiator Company Boilers, Cast-Iron American Radiator Company PRODUCTS FOR EVERY HEATING REQUIREMENT MAGAZINE BOILER No. 25 This coal boiler is self-feeding. As the fuel on the grate burns, additional fuel comes down from the large magazine. There are no moving parts or accessories. Fuel is fed.by gravity at a uniform rate and as needed. Unique by pass directly to chimney provides for quick starting. Ratings: Steam, 300 to 2400 sq ft; Water, 480 to 3840 sq ft. ARCO ROUND BOILER A low priced boiler, well known for reliable and economical service. Optional front pro vides for oil burning. Ratings: Steam, 330 to 875 sq ft; Water, 485 to 1310 sq ft. NEW ARCO ROUND BOILER An old favorite with a new jacket and new features, including the Arco Circu lator on certain sizes. Ratings: Steam, 240 to 690 sq ft; Water 380 to 1100 sq ft. "IDEAL" REDFLASH BOILERS Regular OeLuxt An attractive boiler in regular or Deluxe Model for the modern home. 40 sizes for all fuels provide for every requirement. Special front for oil burning can be fur nished. Ratings: Steam 365 to 7810 sq ft; Water,'585 to 12,500 sq ft. ARCOLA--A simple, hot water radiator system for small homes up to 6 rooms, garages, outhouses, stores, etc. Generally sold complete with radiators. Needs no basement for installation. BOILERS FOR LARGER INSTALLATIONS "Ideal" Water Tube Boilers--Five sizes from 23 in. to 79 in., for large buildings and commercial installations. Sectional construction permits easy installation in old build ings. Ratings: Steam, 880 to 15,530 sq ft; Water, 1400 to 24,870 sq ft. . No. 92 Oil Burning Boiler -- A deluxe model for larger than average homes, apart ments, stores, churches, etc. Ratings: Steam: 1815 to 3675 sq ft; Water, 2910 to 5870 sq ft. EW MAKE IT AN "ALL AMERICAN" JOB! 862 American Radiator Company Boilers, Cast-Iron American Radiator Company 40 West 40th Street, New York, N. Y. CAST IRON RADIATORS AND ENCLOSURES ARCO RADIATORS Small and trim, these radiators have an output equal to old types of larger radi ators. They are handsome as free standing radiators, yet small enough to be recessed. ARCO CONVECTOR CORTO RADIATORS A complete range of widths and heights permits an ap propriate selection of this favorite radiator for any location. Highly efficient, easily cleaned and compact. A cast-iron unit and enclosure designed to gether for most efficient con cealed heating. A complete range of sizes in the Convector and in the enclosure, provides proper com bination for every requirement. FANTOM RADIATORS The Fantom is a wall type radiator, hung on brackets prefer ably under a window, and fully or partially recessed with front exposed and grilled metal stool over top. A COMPLETE LINE OF RADIATOR ENCLOSURES These radiator enclosures have been worked out to combine pleasing appearance with heating efficiency. They are made for every type of radiator, either recessed, semi-recessed or free standing, They are sturdy, easily installed and reasonably priced. Special models may be had on special order. Engineers are giving increasing recognition to the value of ARCO CAST-IRON PRODUCTS FOR INDIRECT HEATING VENTO CAST-IRON RADIATORS Vento Cast-Iron Heaters are used in ' many of the fore most schools,- post offices, clubs, thea tres and other pub- . lie buildings for ef ficient. indirect heating. They have become the stand ard for blower and ventilation systems. PERFECTION PIN For Gravity Indirect Heating with Steam or Water. Threaded Nipple or Flange and Bolt Connections.' SMrMAKE IT AN "ALL AMERICAN" JOB! 863 'l American Radiator Company Boilers, Cast-Iron American Radiator Company 40 West 40th Street, New York, N. Y. PRODUCTS FOR EVERY HEATING REQUIREMENT CONTROLS AND ACCESSORIES EXCELSO WATER HEATER IDEAL DOME TYPE WATER HEATER Provides an easy and eco nomical supply of domestic hot water from a steam or hot water boiler. Water from each section of the boiler passes into the metal shell of the Excelso, heating the domestic water in the copper coils. ` SCUTTLE-A-DAY A practical, coal burning water heater for small homes, stores, etc. Connected with a storage tank, it pro vides ample hot water for domestic use. 3 sizes for vari ous requirements. The Arco Inciner ator--combines the features of the Scuttlea-day water heater with an incinerator. Made in 40 to 90 gal. capacities. A new cast-iron heater for coal burning. Made in 7 sizes, in capacities from 65 to 250 gal. Plant tested to 315 lb. pressure and guaran teed for working pressure of 125 lb. Substantial in con struction and moderately priced. ARCO HIGHTEST TANK HEATER A water heater for large buildings. Lowcost installation and inexpensive operation but will give unsur passed length and quality of service. For either coal or oil. Ca pacities: Coal, 1,500 to 3,000 gal; Oil, 1,520 to 2,520 gal. A COMPLETE LINE OF PACKLESS VALVES, VENTS AND AIR VALVES Arco Packless No. 515 Ideal No. 861 A rCo Valves--Provide Vacuum Air Hurrivent--Its absolute pro Valve--For one- unique construction tection against pipe steam systems.. allows for quick leaks in steam, Eliminates and great venting hot water, air rapidly capacity assuring vapor or vacu and um heating systems. against its return. seals almost instant steam supply from mains to radiators. RCO WROUGHT COPPER FULL- FLOW FITTINGS AND ARCO WROUGHT COPPER PIPE ________ ,RCO Full-Flow Fit tings are the logical companions to copper pipe. They are wrought . copper like the pipe they join, with the same co efficient of heating, cooling, con traction and expansion. Fit tings and pipe available up to 2 in. Pipe is hard or soft temper, and in 3 weights. ARCO METAL PIPE Arco Super Alloy Pipe is strong, machinable and corrosion re sisting. Made of high grade of. cast-iron alloyed with copper and chromium. Furnished in 1H in. to 6 in. sizes, inclusive. Threads and cuts with standard tools. WMAKE IT AN `ALL AMERICAN" 864 American Radiator Company Boilers, Cast-Iron American Radiator (Tympany . 40 West 40th Street, New York, N. Y. CONTROLLED WARMTH SYSTEMS _ The Arco Model K Va'po-Orifice System the design pressure, steam will enter the is- an engineered and coordinated unit return lines, close the vent port of the air which operates to insure equal distribution eliminator, and the system will auto of warmth. On each radiator there is in matically equalize itself, insuring the stalled a special inlet valve with an adjust return of condensate to the boiler. able orifice, by means of which flow of When a zone system is used, the zone steam to each radiator can be accurately valves prevent the self-equalizing action calibrated in accordance with the capacity ' and it is necessary to install an Arco Con of the radiator. The adjustment can be densation Pump to insure-the return of made while the system is in operation. condensate to the boiler. .. Pressure is so controlled that no more Simplicity of design and moderate cost steam is admitted to the radiators than makes possible the installation of this they are capable of condensing. Therefore system for little more than the cost of a no thermostatic traps are required on the One Pipe Steam System. return connections of the radiators. A "Standard Specifications" and "Design thermostatic air eliminator equipped with and Installation Guide" including all a vacuum check is provided. If the pres-... details are available at American Radiator sure through inadvertence should exceed Company branch offices. . 865 Boilers, Cast-Iron Manufacturers of Cast Iron and Welded Steel Boilers, Cast Iron Radiators and Heating Accessories Irvington-on-Hudson, N. Y. Branch Offices Boston; Philadelphia; Chicago; Queens Village, L. I.; Long Island N. Y.;City, Baltimore; Springfield; Lancaster; Pittsburgh; Zanesville; N. Y.Elizabeth; Geneva, . Plants Elizabeth, N. J.; Lancaster, Pa.; N. Y.Zanesville, Ohio; Geneva, BURNHAM BUILT-IN-OIL BURNING BOILER Design Designed especially for securing greatest economy with oil fuel. Is not limited to use of any particular oil burner. Will operate satis factorily with any gun-type burner. Equipped for all year-round hot water supply. Provision made for six auto matic controls insuring posi tive action and safety. , Construction Cast iron.square sectional, en cased in heavy gauge steel jacket, attractively finished in spatter- dash aluminum. Duco lacquered. Jacket of boiler.heavily insulated against heat and sound. Every thing is built-in. Controls are in burner division, reached through door at back. Refractory fur nished with boiler, also water heater, low water cut-off and draft adjuster. . Performance Note all sides of fire pot or combustion chamber are water surrounded, even the bottom. This latter prevents heat from converting the moisture into steam below the usual concrete bottom, with danger of causing explosions. All fire travel is vertical and between a series of staggered teeth which, literally eat up the heat. Between the crown sheet and smokebox, a dis tance of 19 in., approximately 2000 deg of heat is gathered by the water. The fact that when you open the.peep door you can see for yourself, that practically none of the color flames of com bustion go into the fire travel, proves conclusively how perfect is the combustion. It has a particu larly low heat lag, due to the fact that the air supply is cut off soon as burner ceases. No cooling is therefore caused by chimney draft drawing air through the boiler. It is an economy boiler built as Burn ham builds. ' Boiler Measurements Height.......................................57 in. Width....................................... 29 in. Depth........................................36 in. for No. B. ' ' 42 in. for No. C. Water line height.......................46 in. Oil burner chamber................... 13 in. deep 27V2 in. wide 56 in. high Supplies and returns..................two 3-in. supplies . ' " two 3-in. returns Smoke pipe size.........................No. S. B. 8 in. No. S. C..9 in. Height to center, 50Va in. Boiler Ratings No. of Boiler - Equivalent Direct Radiation Minimum Gallons of Oil per Hour to Sustain Rating S. B. S. C. W. B. W. C. Steam 725 1075 Water 1 (60 1720 1.5 2.25 1.5 2.25 There's a Burnham for Every Heating Purpose 866 Boilers, Casi-Iron Irvington-on-Hudson, New York There's A for Every Burnham Purpose Catalogs Sent on Request 1__Welded Steel Boilers--Also Three Purpose Welded Steel Boilers. For heating, hot water supply and incineration. Coal or oil. Com pletely welded for 15 lb working pres sure. Multiple shaking grates. Sizes for commercial or domestic uses. Special folder sent on request. 2--Water Tube Boilers for Steam and Hot Water Heating. 17, 21, 27, and 36 in. Double shaking grates and long fire travel. Rating to . 9,050 sq ft for steam and 15,085 sq ft for water. . 3--Water Tube Boilers Jacketed in Color. 17, 21, and 27 in. Steel Jacket and' 4 ply air cell asbestos insulation. Enameled rich red and black. Jacket goes on after all other set up work. . Rating to 4,225 sq ft for steam and 6,800 sq ft for water. . 4--Burnham Oil-Burning Boilers. A specific-sized boiler for each specific heat job for use with any standard oil burner. Round Sectional Burnhams in 6 series and 24 sizes. Square Burn hams in 5 series and .39 sizes. For steam, vapor, or water. ' 8-- High Pressure Hot Water Supply Boilers. Sectional construction Guaranteed to 120 lb working pressure. Supplies up to 3,800 gal. 9-- -Junior Hot Water Supply Boilers. Will keep 175 to 700 gal tank always full of hot water. Guaranteed to 120 lb working, pressure. 10-- Bumham-Taco Tanks. Combining water heater and storage tank in one unit for summer-winter use. Removable copper heating element. Tanks may be galvanized, evendur or copper. 11-- Burnham-Cast-Iron Radiators. Occupy 40% less space than ordinary cast-iron radiators of same rating. Shorter. Lower. Narrower. 3-tube . type 3J4 in. wide. 4-tube type 4JJ6 in. wide. 5-tube type 5lH263 4m5. w6 i7de. Can be recessed. 12-- Fero Tube Radiators. 5--Big Twin Sectional Boilers. 50 in. Grate, divided for easy shak ing. Twin sections, divided down the middle. Ratings to 19,450 sq ft for steam 31,800 sq ft for. water. 6--Tube Type Smokeless Boilers. For burning soft coal efficiently and without smoke. Meet smoke ordi nances everywhere. Similar to (2) above with addition of smokeless feature. All heights--3, 4, 5, 6, and 7 tubes. 13-- Burnham Air and Vacuum Valves. Full line for radiators, risers and mains. 14-- Burnham Radiator Valves. Complete line of heating accessories. Including steel tanks of all kinds. 7--Round Sectional Boilers. This boiler made the long fire travel famous. Handled easily. Very large 'steam dome. Ratings up to 1,550 ,sq ' ft for steam, 2,560 for water. 15-- Burnham Flexible Headers. 16-- Federal Unit Heaters. Complete line in modem designs. 867 Boilers, Cast-Iron Crane Co. Manufacturers of Valves, Fittings, Fabricated Piping, Steam Specialties, Plumbing and Heating Materials 836 S. Michigan Avenue, Chicago, 111. ' Branches in All Principal Cities . Write for Catalogs and full information on any materials COMPLETE LINE OF RESIDENTIAL AND COMMERCIAL BUILDING BOILERS AND HEATING MATERIALS Crane boilers are made in sectional or round cast-iron styles for hot water, steam, vacuum, and vapor heating with coal, coke, gas, and oil. Individual sizes and capacities up to 10,450 sq. ft. of total steam radiation or 16,720 total hot water; used in batteries, installations with a much larger capacity are available. Crane Radiation includes exposed (legless, bathroom, hospital, wall), concealed and shielded types of high efficiency and graceful design. Unit heaters, humidifying radiators, and a complete assortment of valves, fittings and specialties complete the Crane heating line for residential and commercial use. Crane Deluxe D-l Oil Burning Boiler The ``Sus tained Heat" principle of design incor porated in this boiler assures high combustion efficiency and low standbyloss. Avail able in regu. Iar and deluxe jacket models. Basmor Gas Fired Boiler With the famous Butter fly Bunsen-type burner, this boil er develops high efficiency with negligible standfa y-loss. All types of gas. Available in both regular and deluxe jacket models. Crane Coal Fired Boilers Extended ``ceil ing" surface, con trolled water travel, and a score of oper ating refinements place this boiler on a plane of highest efficiency. Avail able in both regular and del uxe two-tone enamel jackets. Crane Directed Radiation Invisible low-cost section shields throw heat outward into room, equalizing tem peratures, protecting walls and drapes. 868 Crane Co. Boilers, Cast-Iron EVERY TYPE OF VALVE AND FITTING FOR HEATING INSTALLATIONS Crane Welding Fittings--Uniform in cross-section and radius, with ends accur ately beveled to fit pipe or tubing; Tan gents facilitate welding in line. Crane Standard Cast Iron Fittings-- Of dense, uniform metal, with faces accur ately aligned and at exact right angle to flow. Smooth-cut threads, smoothly faced flanges. Crane No. 981 Trap--A cast-iron trap of high capacity. Simple working parts, removable without touching line. Expels condensate in instantaneous action. Crane No. 512 . Gem Union--A ground-joint union with brass to iron seat. No gasket required. Seat ring cannot loosen. Taper threads. Easy to install. 150 lb. steam. - Crane Wedge Gate Valve (Left)--A brass valve with non-rising stem, stuffing box gland, and disc guides that prevent wear of seating surfaces. Can be packed while wide open under pressure. For steam working pressures up to 125 lb. Crane Double Disc Gate Valve (Right) --A brass valve with rising stem, parallel seats, and wedging device assuring equal bearing on all parts of seat. Can be packed while wide open under pressure. For steam working pressures up to 125 lb, Crane No. 1168 L. P. Pop-Safety Valve--A side-outlet valve of mal leable iron, with brass trimmings, for steam heating boilers. Sturdy rigid base and ample clearance for tools. Reggularly set at 5, 10 or 15 lb.; available at 3 to 25 lb. Crane No. 984 Air Vent -- An automatic vent to remove air - from water mains, hot water heating sys tems, tanks. Oper ation similar to the No. 981 trap. Simple, low in price. Boilers (Cast-Iron) National Radiator Corporation General Offices: Johnstown, Pa. Sales and Service Through These Branch Offices and Warehouses Baltimore Boston Buffalo Chicago Cincinnati Cleveland Philadelphia Lebanon Pittsburgh New York Richmond Milwaukee Washington HEATING EQUIPMENT National Boiler Bond --Issued and backed by a great independent surety company, a bond is given free with every National Bonded Boiler. It guaran tees workmanship, ma terials, and official pub lished ratings. Bond fully covers the purchase price of the boiler. National Bonded Contento Boiler For radiator systems in small homes or structures with or without basements. Hot Water only. Made in 5 sizes, with bonded ratings from 225 to 545 sq. ft. Burns hard coal, soft coal or coke. National Bonded Gas Boiler French gray enamel finish, chromium base and dome, fully enclosed. Made in 2 series and 16 sizes. Certified A.G.A. ratings from 300 to 2250 sq. ft. Steam, and 480 to 3600 sq. ft. Water. 0d National Bonded Jacketed Square Boilers Red baked-enamel jacket, black base and doors. Made in 3 series and 14 sizes, to meet the requirements of every modem home. Bonded ratings from 200 to 1400 sq. ft. Steam, and 330. to 2310 sq. ft. Water. Insu lated with rock wool. National Bonded Jacketed Oil-Burning Boilers Red baked-enamel jacket, with black base and doors. Furnished with special front lor either rotary or gun type burner. Made in 3 series and 14 sizes. Bonded ratings from 395 to 1570 sq. ft. Steam, and 632 to 2512 sq. ft. Water. 870 National Bonded Round Boilers Business - like and efficient; an established favorite in many districts. For any fuel. Made in 6 series and 18 sizes. Bond ed ratings from 1.75 to 925 sq. ft. Steam, and 285 to 1530 sq. ft. Water. Triangular or flat type grate bars are optional. Boilers National Radiator Corporation HEATING EQUIPMENT National Bonded Novus Sectional Boiler (Including the Imperial Sectional Boiler.) Burn any fuel. Largest sizes iave divided sections. Five series, 31 sizes. Bonded ratings from 480 to 7000 sq. ft. Steam, and 790 to 11500 sq. ft. Water. I mperial Sectional is of the Utica design. National Bonded Irern Water ^jae4oiler Eliminates high boiler room ceilings and boiler pits. Burn any fuel. Made in 2 series, 21 sizes, hard-coal or smokeless. Bonded ratings from 850 to 6600 sq. ft. Steam, and 1400 to 10,890 sq. ft. Water. Rear smoke out let on larger sizes. National Bonded Super-Smokeless Boiler These smokeless boilers have demonstrated their ability to meet smoke ordinances in all parts of the country. Three series, and 24 sizes. Bonded ratings from 750 to 8300 sq. ft. Steam, and 1250 to 13,695 sq. ft. Water. National Premier Steel Boilers Have recessed front smoke chamber, water jacketed five sides. Models for hand or stoker, oil, or gas firing. 11 grate widths, 29 sizes. Type C fur nished in hard coal, or smokeless types. Ratings ... 485 to 42,500 sq. ft. Steam; S.H.B.I. Code. National Aero Panel and Tube Radiators National Panel Radi ation (shown at top of illustration) has iron-toiron contact on front face. Made in 1, 2, 3, 4 and 5 tube depths in varying heights. Aero Tube Radi ation is made in 3, 4, 5, 6 and 7-tube styles, in vary ing heights. National Aero CastIron Convectors Proven dependability and permanence. Made of lifetime metal. 8 sizes and models, for recesses 3%, 4y8, b%, 7% and 9)4 inches deep. Any length, in multiples of 2 inches. Fin spacing provides large volume of moderately warmed air. Ask the Nearest Branch for complete technical information on any of these National Radiator Products. 871 Boilers, C. I. and Steel Tubular Spencer Heater Company New York. N. Y. Philadelphia, Pa. Baltimore. Md. Williamsport, Pa. Branch Offices and Representatives Boston. Mass. Springfield, Mass. Washington. D. C. Albany. N. Y. N.Binghamton, Buffalo. N. Y. Y. Syracuse. N. Y. Allentown. Pa. Scranton, Pa. Spencer Automatic Magazine Feed Heaters are made in cast-iron sectional types for steam, vapor and hot water heating. Also in steel tubular types for larger buildings. There are sizes and capacities to provide economical and convenient heat--safe and sure --for every type of building. Spencer is the original magazine feed heater with a record of more than 37 years' successfuPoperation. They are sold and installed by all good heating contractors. fuels; or the steel magazine feed heaters, also for No. 1 Buckwheat. Goal - Coke - Gas - Oil--Spencer J'and L series cast-iron and steel tubular heaters are primarily designed to burn low cost No. 1 Buckwheat anthracite and the C-N series Nut or Pea anthracite or coke. If at any time a home owner desires to burn more expensive fuels--oil or gas-- a Spencer Heater will show a higher efficiency than can be secured with any ordinary boiler. Thermostats--A Minneapolis thermo stat and electric damper motor are fur nished as optional equipment. Jacketed Covering--Attractive metal lic jackets, as illustrated are available for Spencer Cast-Iron Heaters. Why Spencer Heaters perform so satis factorily can best be explained by a brief inspection of their design and construction. The Spencer principle--as illustrated in the cross sectional view--is simple: Once a day fuel is put into the magazine (A). It fills the sloping grate to the level of the magazine mouth (B). The fire bed always stays at (C) for as fast as fuel bums to ash (D; it shrinks and settles on the sloping grate (E) and more fuel feeds down automatically over the top of the fire bed. Fuel feed is by gravity alone, in just the right amount to keep the fire always burning at its most efficient combustion point. This explains why a Spencer Heater. always gives the same uniform satisfying heat, and bums low cost coal economically. These exclusive Spencer advantages are available in all types, J and L series, castiron sectional, burning low cost No. 1 Buckwheat; the C-N series for larger . *The Spencer Heater Company guarantees that when installation is made in accordance with accepted standards, the heater will carry the number of feet of direct cast-iron column radiation listed. This allows ample provision for heat loss in covered mains, risers and returns, and for peak loads. 872 Spencer Heater Company Boilers, C. I. and Steel Tubular SPENCER STEEL TUBULAR MAGAZINE FEED BOILERS For larger buildings we recommend Spencer Steel Tubular Boilers, also of the magazine feed type, burning low cost No. 1 Buckwheat anthracite or coke. In the cross-section diagram illustrated here, part of the fire bed is cut away to -show the sloping grates and the two maga zines filled with fresh coal, ready to feed down automatically of its own weight to the fire. These boilers are built in two vertical sections for ease in handling and installation--a great advantage on re modeling or replacement jobs, eliminating necessity of costly tearing out of walls, etc. Combination water tube and fire tube construction. Built toA.S.M.E. standards. SPENCER STEEL BOILERS, FOR OIL, STOKER OR GAS For more than 37 years Spencer has been building efficient, econo mical and depend able coal burning boilers. With this background of ex perience, Spencer engineers have developed the Spencer Steel Boiler, for oil, gas or stoker. The high sus tained efficiency of these boilers means adequate heat for low fuel cost., Design is of the three-pass type. Combustion chamber is amply large. Built of open hearth steel boiler plate and electrunite tubes--a quality product for dependable service. Furnished with Taco indirect domestic water heating coils either of the storage tank or instantaneous type. Sizes and Guaranteed Capacities CAST-IRON SECTIONAL TYPE STEAM WATER No: 49 Q-f "Guaranteed Direct Cast 1 Iron Column Radiation Loads. Sq. Ft. tE.D.R. Rating "Guaranteed 1 Direct Cast Iron Column Radiation Loads, Sq. Ft. , Sizes and Guaranteed Capacities No. M6-6 M6-7 M6-8 M6-9 M6-I0 M7-6 M7-7 M7-8 M7-9 M7-10 STEAM "Guaranteed Direct Cast-Iron Column Radiation Loads, . Sq. Ft. 2300 2600 2900 3200 3500 4000 4700 5400 6100 6600 tELDJL Rating 2875 3250 3625 4000 4375 5000 5875 6750 7625 6500 J-3 j-4 J-5 O L-105 Z 35 L-106 L-107 L-205 L-206 L-207 L-208 s L-209. L-305 L-306 fDfi L-307 L-308 L-309 L-310 L-311 MS-6 8000 10000 M8-7 9750 12185 MS-8 11500 14370 CN-502 M8-9 13250 . 16555 hr* CN-502V-! MS-10 15000 18740 fE.D.R. ratings represent the attached net radiation load plus piping losses' expressed in square feet of equivalent direct radiation (240 B.t.u. steam. 150 B.t.u. water) which may be placed on heater in accordance with accepted standards for CN-5G3 zfeSz CN-5K3 CN-504 CN-5K4 CN-505 o CN-5K5 CN-506 - economical operation. ' <7* - 873 175 265 355 390 510 630 550 725 900 . 1075 1250 1150 1500 1650 2200 2550 2900 3250 280 360 . 440 520 600 680 760 840 920 220 290 330 440 440 590 490 645 640 845 790 1045 690 910 910 1200 1(30 1490 1350 1780 1570 2070 1430 1870 2310 2750 3190 3630 4070 1900 - 2475 3050 3625 4200 4775 5350 350 460 450 590 550 . 725 650 860 750 995 850 1130 950 1265 1050 1400 1150 1535 360 550 740 800 1050 1300 1140 1500 1860 2220 2580 2375 3095 J 3815 4535 5255 5975 6695 575 735 905 1070 1235 1400 1565 1730 1895 Boilers, Cast-Iron United jStates Radiator (corporation Detroit, Michigan, U. S. A. Capitol Fincast Convectors Illustrated above is the "0" Series Boiler for horizontally fired "gun type" oil burners. The high efficiencies of this boiler are due to a new method of heat absorption through extended rib type heating surfaces. The boiler is of the wet base construction, which absorbs heat that would ordinarily be lost through the floor. Year 'round domestic hot water is pro vided. Construction is of cast-iron. A heavy jacket and a thick blanket of rock wool completely insulate the boiler. CAPITOL FINCAST CONVECTORS AND ENCLOSURES Made entirely of cast-iron. Made without joints. Cast in one piece. Many lengths and widths. Tappings--top, bottom or ends. Complete choice of enclosures. THE CAPITOL AIR CONDITIONER CAPITOL RADIATORS Capitol Radiators give mellow glowing warmth where you want it and when you want it. Homes heated with Capitol Radiators are comfortable, clean and healthful. Capitol Radiators have the added ad vantage of the most approved type of as sembly; Extra heavy malleable iron push nipples, machined with hair-breadth precision, form a tight, iron - to- iron joint. They need no gaskets, have no threads to rust, are taken apart and assembled with the greatest ease. For use in residences and small buildings. Flexibility to meet the individual re quirements of the building is the keynote of design in the Air-Conditioner. The owner may have a completely air-con ditioned building; he may have a partially air-conditioned building with modem steam or hot water heating in less fre quented r.ooms; or he may have a system that conditions the air in the winter with a certain amount of cooling effect during the summer, due to circulation of air by a big quiet fan. 874 Boilers, Cast-Iron Weil-McLain Company Manufacturing Division: Michigan City, Ind. and Erie, Pa. General Offices: 641 W. Lake Street, Chicago NEW YORK OFFICES: 501 Fifth. Avenue Prompt Wetf-McLain Boiler and Radiator service iB made conveniently available through local stocks carried by Weil-McLain Distributors in most of the important distributing centers. PRODUCTS--Cast-Iron Heating Boilers and Water Supply Heaters, Cast-Iron Radiators including standard tubular senior and junior types, "RAYDIANT" Concealed Cabinet and Wall Radiators, and Humidifiers. Weil-MPLain boilers Weil-McLain Boilers are made in various types and in a wide range of sizes to satisfy every heating need and demand. The conventional line includes the Round, * Jacketed, Square, Self-Feed and Smokeless types. A more recent addition is the Jack eted Type Round Boiler built especially for Automatic Heating with Oil, Gas or Stoker. Sound Jacketed Square 7lau/xlLan The Weil-McLain Raydiant Radiator is made in both concealed and cabinet en- closure types. It emits a scientific blend of radiant warmth and converted heat. Made entirely of cast-iron, it forms its own live metal front and grille. Has space saving advantages, low roughing-in and setting cost. Vents equally well on all systems. Sdf Peed Jacketed Alt-Fuel Jacketed Oil Burning Cabinet Type Concealed Type Junior Cameo Wul-McLaih Radiators Weil-McLain "Cameo" Radiators are made in a complete range of sizes, heights and widths, for every place and purpose in modem homes and buildings. Besides the regular floor type, Weil-McLain also make other types of "Cameo" such as the ^ Junior floor type radiator, "Cameo" Wall and Bathroom types. 875 )Boilers (Oil Fired Delco Appliance Corporation . Subsidiary of General Motors Rochester, N. Y. Delco-Heat Harmonized Boiler . A Complete Unit with Boiler and Burner Designed for Each Other--To secure the greatest benefits with the use of oil as the heating medium, it is necessary to have a boiler which is designed to be used with oil heat. An oil burner operates at full volume as soon as it is turned on. It is therefore necessary that a very large heating surface be provided in the boiler to absorb this heat as rapidly as possible in order to prevent waste. The Delco-Heat Boiler is designed with the proper heating surface to insure this efficiency of absorp tion with the type of flame produced by the Delco-Heat Burner. The Boiler is built for steam vapor or hot water heating systems. It has capacities of from 625 to 1725 sq ft of steam radiation and from 1000 to 2750 of hot water radia tion. It can be passed through any average doorway in units not exceeding 420 lb in weight. The boiler section is insulated on top and all sides with heavy insula tion. The bottom . of the boiler is uninsulated to heat the air which passes under the boiler to the burner and is pre heated before being used for combustion. The steel cabinet, finished in two- tone green and chromium, en closes the boiler and all equipment and controls. One of the advantages of the design of this boiler-burner unit is that the burner is located in the front of the cabinet, entirely outside the combustion chamber. It is therefore easily accessible if servicing is required. It is designed and built as part of this boiler but otherwise is similar to the standard Delco-Heat Burner. The Burner is designed to utilize low cost domestic fuel oil which requires no preheating. Efficiency of Fins and Construction The efficiency of cast iron fin type con struction for heat transmission has been demonstrated for two decades in air-cooled Delco-Light electric plants where rapid heat liberation is desired. In the DelcoHeat Boiler, the process is reversed and cast iron fins rapidly absorb the heat from flame and gases in the boiler. The fins contain a thin sheet of water which quickly absorbs heat and circulates back into the main body of water, causing quick steam ing. The position of fins and the stag gered and broken-up flame and gas flow are clearly shown in the illustration. Pro gress of the flame is thus delayed until it finally enters a central duct at top of the boiler and then passes out the flue. The upper nipple port is unusually large, permitting free circulation of water and steam within the boiler. Unre stricted circu lation above the crown sheet is possible because of the unusual design. The boil er operates with a steady water line which is impor tant, as a fluctuat ing water line operation might cause low water Ddco Heat Boiler Sections rut-off and stOD Showing Fin Arrangement urner The boiler is used for steam, vapor or hot water heating systems, the only difference being in the accessories. The hot water heater consists of a special copper tube set into the rear section of the boiler and sub merged in the boiler water. There are two capacities. On the DL-3, DL-4 and DL-5 boilers, the hot water heater will raise 33 gal of water 100 deg (when the boiler is 180 deg) each hour. On model DL-6 under the same circumstances, the heater has a capacity of 50 gal per hour. Automatic Controls Complete Automatic Control Service is standard equipment with the Delco-Heat Harmonized Boiler. See also Pages 8S5 and 890 876 Boilers, Steel THE BABCOCK & WILCOX COMPANY 85 Liberty Street, Manufacturers of New York, N. Y. Water-Tube Boilers Oil Burners Chain-Grate Stokers Seamless Steel Tubing and Pipe Branch Offices and Representatives in all Principal Cities Type H Stirling Boiler The Babcock & Wilcox Type H Stirling Boiler is a highly efficient unit built for moderate pressures at moderate prices. . . . and is designed to occupy minimum floor space and head room for the heating sur face required. . This boiler is built in four classes and 36 sizes ranging from 691 to 4980 sq. ft. of heating surface, and can be designed for operation with any fuel and every method of firing. The moderate price is due only to the simplicity of design, efficient production methods and superior shop equipment. Heating Surface 1Floor to Center of Mud Drum, 1Ft.. In. 1*loor to Face of Steam Outlet, Ft.. In. Floor to Top of . Boiler, Ft.. In. Size of Steam Outlet, In. ceo Width ofSetting CO Iw o Single Boilers JS C Boiler, in 3 S-j Ft., In. Battery O Qlt. Ft.. In. 691 15-2 6-0 11-0 5-2 921 * 7-0 13-0 8 115; 8-0 15-0 8 H-1 m: 9-0 17-0 8 1612 10-0 19-0 8 1841 8 11-0 21-0 8 2073 12-0 23-0 8 2304 13-0 25-0 " 14-5'/, 14-2'/. 8 88 5 8 8 8 8 8 8 877 17-$ 6-0 1 165 7-0 1462 8 . 8-0 HJ 1754 9-0 2046 10-0 233S 11-0 2631 12-0 2924 13-0 11-0 13-0 15-0 17-0 19-0 21-0 23-0 25-0 4-9*4 14-5'/, 14-2'/, 8 8 888 88 88 88 808 8 5 8 8 8 8 8 8 * 1063 20-2 6-0 1417 7-0 1772 8-0 2126 9-0 H-3 248(1 2835 " 3189 8 3544 8 10-0 11-0 12-0 13-0 3898 * 14-0 4252 15-0 11-0 13-0 15-0 17-0 19-0 21M> 23-0 25*0 27-0 29-0 4-5'/, 14-5'/, 14-21/. 5 8 88 8 ' 8 8 888 8 8 8. 8 8880 8888 , 8 8 8 V . 8 8 .8 6 88 86 1245 22-8 6-0 1660 7-0 11-0 13-0 4-1Vt 14-11 8 14-5'/2 a 5 8 2075 8 82490 8 8-0 15-0 9-0 17-0 8 - 8' 8 8 8 - 8H-4 2905 * 10-0 19-0 8 8 8 3320 8 11-0 21-0 8 8 8 8 3/35 8 12-0 23-0 8 8 8 8 415(1 8 13-0 25-0 8 8 8 8 4565 8 49801 8 14-0 15-0 27-0 29-0 8 U 88 * * 6 6 Type H Stirling Boiler with Babcock <& Wilcox Chain-Grate Stoker The advantages of the Babcock & Wilcox Type H Stirling Boiler may be sum marized as follows: Unusual steaming capacity for the floor space and head-room required. Boilers may be set singly or in battery. Setting heights can be varied to suit any condition of firing. The choice of three locations for gas exit reduces cost of flues and breeching. Distribution baffles make effective all of the heating surface. . Tube renewal is facilitated by correct tube spacing, and a tube removal door. Soot blowers can be readily installed to simplify thorough cleaning of all tubes. A superheater can be furnished with out any change in the standard design or construction. The boiler is supported by a structural- steel framework entirely independent of the brickwork. Ample provision is made for free movement of parts due to expansion and contraction. A complete table of sizes and dimensions, . together with pertinent installation data, is contained in a new 32 page bulletin which will be sent upon request. Simply ask for Bulletin G-8-A. 877 Boilers, Steel The Bigelow Company Established 1860 ' Main Office and Works Boston, Mass. New Haven, Connecticut Philadelphia. Pa. New York, N. Y. Syracuse. N. Y. Manufacturers of Bigelow-Hornsby Water Tube Boilers, Bigelow Low Head Water Tube Boilers, Bigelow Three Drum Vertical Water Tube Boilers, Bigelow Horizontal Return Tubular Boilers, Bigelow Electric Steam Generators, Bige low Scotch Type Boilers, Bigelow Two-Pass Boilers, Bigelow Manning Boilers, Bigelow Upright Boilers. Two 60 hp Bigelow Two-Pass Boilers used for heating the new Heme Office Building of The Hartford . Steam Boiler Inspection and Insurance Co., the largest insurer of steam boilers in the United States Since 1860 it has been the endeavor of The Bigelow Company to merit a reputation for constructing boilers of a high standard of design, workmanship and material. We are proud of the confidence shown in us by the use of Bigelow boilers in this building. The Bigelow Two-Pass Boiler is designed to meet heating and power requirements, especially where space limitations prevail. It contains the recognized features of the well-known H.R.T. boiler, but due to the small amount of brickwork required it can be in stalled at a lower complete cost. The elimination of special brick shapes and staybolts in the furnace reduces the cost of maintenance to a minimum. Built in units from 25 to 250 Hp for power service, and the 15 lb. heating class in units from 3500 to 35000 sq ft of steam radiation. BIGELOW SCOTCH TYPE BOILER Modeled after the Scotch Marine type of boiler, this boiler has many advantages to warrant its use in the industrial field for power and heating. Self-contained--Com pact--rLow water-line. Built in units from 15 to 300 hp. The 15 lb. welded heating type* built in units from 1800 to 35000 sq ft of steam radiation. 878 Boilers, Steel Combustion Engineering Company, Inc. 200 Madison Avenue k C-E STOKERS Combustion Engineering leads in the manufacture of stokers, other than domes tic, in extent and variety of work done, nearly 14,000 C-E Stokers having been installed to date. Combustion Engineer ing's line of larger stokers includes the fol lowing, three of which (Type E, Coxe and Green) are the leaders in their respective fields. - Type K Stoker--A single retort under feed stoker for burning bituminous coals under boilers in the upper size range of the C-E STOKER-UNIT C-E Stoker-Unit. '. : for burning bituminous cool under boilers ranging from small healing units to power boilers developing up to 400 hp. Fuel burning rates from 60 to 1600 lb per hour Type E Stoker--A single retort under feed stoker for burning bituminous coal under boilers up to about 600 rated hp. C-E Multiple Retort Stoker--For Features A Self-Contained Unit--Hopper, fuel feeding and distributing mechanism, grate,. windbox, driving mechanism and forced ' draft fan combined in a compact unit. Installation--The small clearances re quired usually permit installation with only slight alterations to existing settings. burning semi-bituminous and bituminous coals under boilers up.to the largest sizes. Coxe Stoker--A traveling grate stoker for burning small sizes of anthracite, coke breeze and lignite. ' . . Green Stokers--A chain grate' stoker available in both natural.and forced draft types for burning non-caking or free- burning bituminous, coals. Stoker body is shipped completely as sembled ready for installation. C-E BOILERS Hopper--Non-clogging and- easily re Combustion Engineering Boilers include movable. Does not interfere with access all fire tube and water tube types in sizes to firedoors. Located at convenient height ranging from 25 hp up to the largest. In for filling with shovel. cluded are all designs formerly known by Coal Feed--Screw conveyor, protected the trade names "Heine, " "Walsh & from heat, advances the coal from hopper Weidner," "Casey-Hedges" and "Ladd." to entrance of retort. Reciprocating Classified broadly, the various types of C-E pusher in retort continues the feeding and Boilers are as follows: BENT TUBE--mul provides agitation of the fuel bed in the ti-drum, four-drum, three-drum, two-drum retort zone. . (complete steam generators). STRAIGHT Grate Surface--Alternate fixed and TUBE--sectional header, box header moving grate bars. Designed for correct (cross drum and long drum). STEAM air distribution and made of a special heat resisting iron assuring low maintenance. Air Supply--Integral forced-draft fan, with inlet damper control, supplies air to windbox under the stoker. Volume of air may be regulated by control lever to suit' GENERATORS--complete standardized units available in two types. FIRE TUBE -- hrt, vertical, internally - fired, locomotive type. MARINE--sectional header, bent tube. WASTE HEAT-- straight tube, bent tube.. the rate of coal burning. Control--Stoker is operated by simple lever control for both coal. feed' and air supply. Operation--Simple, easy and depend able. Variable-speed transmission per mits sixteen rates of coal feed. Control levers conveniently located. Design of dump grates prevents avalanching of fuel bed when in dumping position^ C-E PULVERIZED FUEL SYSTEMS C-E Pulverized Fuel Systems, formerly known by the tradename "Lopulco," are available in both direct fired and storage . types for boilers ranging from 200 hp up to the largest. Combustion Engineering has recently placed on the market the Ray mond Bowl Mill, the most advanced design of pulverizer now available. 879 Boilers, Steel Fitzgibbons Boiler Companyjnc. Established 1886 General Offices: 570 Seventh Avenue, New York, N.Y. Works: OSWEGO. N.Y. Branches and Representatives in 55 Principal Cities PRODUCTS--The Fitzgibbons line of Steel Heating and Power Boilers, manu factured under the Steel Boiler Manufacturers Code, meet the heating re quirements of all buildings from the small home to the gigantic modern sky scraper. The line includes types for burning anthracite, bituminous (soft) coals or coke, and for oil, gas or stoker firing, in steam, vapor, vacuum or hot water systems. In other words, there is a Fitzgibbons Steel Boiler for every fuel, and every heating system from the smallest to the largest. RATINGS: All boilers of the line are rated in accordance with the S.H.B.I. Code. FITZGIBBONS OIL-EIGHTY AUTOMATIC Residence Steel Boiler for Oil Burning Ratings, Steam--12 Sizes--425 to 2680 Sq. Ft. Outstanding Features Tanksaver (optional) supplies year 'round clean hot - water without a separate storage tank. Tank- heater (optional) a more efficient indirect water heater. Combustrol, automatically maintains balanced draft, diverts back drafts, prevents back firing. Thermalizer, makes every tube do its full share of heat absorbing. Copper-Steel Plate Construction, combines maximum strength with corrosion resistance. Attractively Jacketed. Teams up with any good rotary or gun type burner to form a unit of Highest Efficiency. ' ' Models: Standard--for rotary burners and for exposed gun type burners. Type B--for gun type burners where the burner is completely concealed but readily accessible through easily removable panels. Catalog on Request FITZGIBBONS COAL-EIGHTY Jacketed Residence Steel Boiler for Coal Ratings, Steam--400 to 1000 Sq. Ft. . *' Outstanding Features Modemly Attractive--A tastefully colored, heavily insulated steel jacket puts this boiler far in advance of coal burning boilers from appearance standpoint. Sets new standards of coal burning performance because of Thermalizer and other efficiency increasiitg features. Tankheater, a completely: sub merged, more efficient indirect heater, is standard equipment. Fitzgibbons Copper-Steel Mate Con struction provides maximum strength and durability. Ideally suited for Mechanical Firing with Stoker or Blower. Catalog on Request 880 Fitzgibbons Boiler Co., Inc. Boilers, Steel FITZGIBBONS R-Z-U JUNIOR Multi-Service Steel Boiler ratings, steam Coal Burning Type------ 750 to 3200 sq. ft. ` Oil Firing Type..--.......... 1003 to 3893 sq. ft, . Stoker Firing Type-------1003 to 3893 sq. ft. Outstanding Features Tanksaver (optional) supplies year 'round 'hot water without a separate storage tank. Tankheater (optional) a more efficient in direct water heater. Auxiliary Grate (optional), for refuse disposal and stand-by heating duty in oil fired installations. Com pact, largest size will pass thru a 31 in. door way. Low Water Line, eliminates need for a pit. Jacket (optional), on all types. Descriptive Bulletin on Request R-Z-U 600 and 800 Seriet FITZGIBBONS Z-U Steel Firebox Boilers Built for 15 lb. w.s.p.--A.S.M.E. Code. Up-Draft Type..... 1800 to 35,000 sq. ft. steam FITZGIBBONS R-Z-U Steel Firebox Boilers The Z-U arranged for rear smoke outlet. Built for 15 lb. w.s.p.--A.S.M.E. Code. UP-Draft Type 1800'to 35,000 sq. ft. steam Smokeless Type.__1800 to 35,000 sq. ft. steam Oil, Gas, Stoker Type...................2190 to 42,500 sq. ft. steam FITZGIBBONS "F" SERIES Portable Riveted Firebox Boilers Built for 100 lb. w.s.p.--A.S.M.E. Code. Ratings, steam--1800 to 15,000 sq. ft. . FITZGIBBONS 500 SERIES Portable Welded Firebox Boilers-- Return Tubular Built for 15 lb. w.s.p.--A.S.M.E. Code Ratings, steam--3500 to 35,000 sq. ft. FITZGIBBONS 700 AND "P" SERIES Portable Riveted Firebox Boilers 700 Series built for 15 lb. w.s.p.--A.S.M.E. Code. Ratings, steam--3500 to 35,000 sq. ft. "P" Series built for 100 lb. w.s.p.--A.S.M.E. Code. Ratings, horse power--25 to 250. .: FITZGIBBONS 600 AND 800 SERIES Smokeless Down-Draft Riveted Firebox Boilers . Built for 15 to 100 lb. w.s.p.--A.S.M.E. Code Ratings, steam--3500 to 35,000 sq. It. Descriptive Bulletins on any. or all of above boilers will be mailed on request. Boilers, Steel Farrar & Trefts Incorporated Buffalo, N. Y. HEATING AND POWER BOILERS Bison Compact Boilers Bisonette Compact Boilers Firebox Return Tubular Boilers Firebox Locomotive Type Boilers Scotch Marine Type Boilers Vertical Boilers . Horizontal Return Tubular Boilers Bison Two-Pass Return Tubular Boilers Established 1864 STEEL PLATE CONSTRUCTION Storage and Pressure Tanks Receivers, Welded or Riveted Steel Pipe, Welded or Riveted Buoys, Welded or Riveted Condensers and Kettles Smokestacks and Breechings Special Work in Stainless Steel, Everdur, Nickel, Aluminum or Monel Metal The F&T Bison Compact Welded Heating Boiler is more than just another boiler. It has been designed carefully so as to have a large furnace volume, the proper volume of water, just 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 first cost and economical in operation. Construction is in accordance with the A.S.M.E. Code for 15 lb. working pressure and boilers are designed for hand firing with anthracite or bituminous coal or for mechanical firing with oil, gas or stoker. There are various sizes available from 1800 to 35,000 sq. ft. of steam radiation, all ratings as required by the Steel Heating Boiler Institute. . The Bisonette Compact Boiler has the same characteristics as the larger Bison Compact Boiler. It has been 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. They are constructed to measure up to the high standards set by Heating Engineers and will give unfailing service under all conditions. Being economical to install and operate, they are highly favored by Architects 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 of riveted construction for power purposes at 100, 125 and 150 lb. working pressure in accordance with the A.S.M.E. Code. 'Sizes Fireboz ^urn Tubular Bailor from 1800 to 35,000 sq. ft. of steam radiation, as rated by the Steel Heating Boiler Institute, are designed for hand firing with coal or for mechanical firing with oil, gas or stoker. . The Bison Two-Pass Return Tubular Refractory Lined Boiler is favored by many Engineers" because it - Eliminates Water Legs, Flat Sides and Staybolts. This boiler is dependable for long years of continuous and eco nomical operation. It stands up under heavy loads and provides that surplus of power, so often needed. This type of boiler is made of welded construction for 15 lb. working pressure and of riveted construction for 100, 125 and 150 lb. working pressure in accordance with the A.S.M.E. Code. Boilers are designed for ratings from 25 to The Bison Tuxr-Paes 250 hp. and are inspected, tested, and stamped by a repre sentative of a reliable insurance company before shipment. They are furnished for hand firing with coal or for mechanical firing with oil, gas, or stoker. 882 Boilers, Steel E. Keeler Company Williamsport, Pa. Established 1864 Riveted Steel Boilers For Heating and Power Steel Stacks, Breechings and Plate Fabrications The Keeler Type "CP" Water Tube Boiler Embodies These Important Features 1. It is completely steel encased and insulated. 1 2. No brickwork required except for front wall and bridge wall. 3. The sides of the furnace are water cooled. 4. Clinkers cannot adhere to sides of furnace. ,. 5. Furnace maintenance costs are reduced to a minimum. 6. Provides very large capacity in a given space. - 7. Can be operated at high, overloads without disturbing water level. 8. Has built in soot blower. Easy to clean interior or exterior. 9. Made in large range of sizes in pressures up to 450 lb. 10. Units as large as 250 hp can be shipped completely assembled. 11. Units larger than 250 hp are shipped knocked down. 12. Highly efficient with any method of firing. The E. Keeler Company manufactures Straight Tube Water Tube Boilers, both long drum and cross drum types, Curved Tube Boilers, both three drum and four drum types, Return Tubular and Double Duty Fire Tube Boilers for every power or heating re quirement. Keeler Double Duty Boiler Before Encased Bulletins of Any Type Sent on Request 883 Kewanee Boiler Corp. 884r Kjewanee, B oiler C9RP?Rati9n Kewanee, Illin o is BRANCHES IN 60 PRINCIPAL CITIES Steel H eating and Power Boilers, W ater Heating Garbage Burners, Tabasco Heaters and Tanks. Boilers, Steel Kewanee Boiler Corp. 1gl*fc38 - &<5I< Z .js o CQ 885 sto tros to $QO-`0 CO88*225 e* N8N**-* ' snN rt ss* 1 Hi S hr<*S <o # so sg=0> sa 00 So -- 9? ?8sgo SS Sli-01 as ts --*orr%-tmSmgsSo; o2m2 Q 22J" 82 o ** S2S5 S --SSm ^, 88 SPJ|2*> SS 8*^oj2 |g ojS 8| p> gSrHoOfA ii (4 8|' V CO = SSz=-i Sl eo ssm"t' E. !B o ile r N o .................... ................ 307 308 1 309 310 314 315 --8SiA*3ffr^o. 22t ^>r -- Ort L^OOPS' OmCO a;-- SS --o(mAmO/>~miaOr>> : :d.s.i ; m;; >j : ; c ; ; 'pl"N 3J b : :.S2 : : **8`5 -J-? : : rmm So S 5 tNCM o S' 5como nn ii -- ii 11 Hi 3 9 ao 5 B o ile r N o .......................................... 407 408 409 410 412 ! 413 | 414 415 ' 416 ; 417 419 | 420 | 421 | 424 Rated Capacity, Steam, aq. it.: Burning Coal, Hand Fired............. ! 2550 Oil. Gat or Stoker Fired................. 4730 OWviderth-aallnHdeLigehntg.`t.h....................................i.n.....x..fitn.. 48x8.6 84 Height of Water Line.................. .in. 71 Approximate Weight: .' Coal Burning........................... lbs. 6900 Oil Burning.':.......................... lbs. 6400 3340 4170 4300 5130 6070 7440 8760 8700 10310 12420 14560 16350 18240 21200 23950 30930 33980 5270 6340 7040 7900 8760 9600 10640 11480 13220 15780 17680 19850 22150 25730 29080 37500 40480 48x9.5 48x11.1 54x10 54x11.1 54x12.1 60x12.4 60x13.6 60x14.3 60x16.2 66x15.8 66x17.3 72x15.9 72x17.5 78x17.9 78x19.9 84x20.1 84x22.1 84 84 89 69 69 98 98 101 101 107 107 113 >13 115 115 121 121 71 71 76 76 76 83 83 87 87 90 . 90 96 96 97 . 97 105 i 103 7400 6800 8300 9000 9800 7600 8300 9000 10600 13200 14100 15900 17300 20400 22000 24000 25700 28000 31000 37000 40000 9700 12000 12800 14600 15900 18800 20200 22000 23600 25800 28600 34300 37100 749 750 751 752 753 754 . RtCdo. aCla, pH.a, Sndt:,Fsiqre. dft..:. . . Oil, Gas or Stoker...,. Width 8t length, in ji ft. Overfall Height....... in. Height of Water Line, in. Approximate Weight: COoilaBl Burunrniningg.............llbbss.. O-m*-Omo MISI<OAs(<NsmCO>rsisT'.* ' mmm^^mKtrs^*N.. mmo 2690 i 3250 3260 ' 3940 36x6.3 36x7.3 W 4700 5200 3800 4200 4060 4550 4930 5520 42x7.9 42x8.5 6000 6500 ; 5000 5400 tsc wN*(A<nXc(oAN 8-- m 757 758 M 8 o wt-> 1 761 763 764 765 766 767 768 769 770 5950 6470 7000 8280 9610 10850 12110 14300 16380 18660 20750 22520 25530 28780 33070 7220 7850 8500 10040 11670 13180 14700 17420 , 19880 22650 25200 27300 31000 34900 40150 48x9.4 48xt0.0 48x10.6 54x9.7 54x10.8 60x10.4 60x11.3 66x11.9 66x13.2 72x12.7 72x13.8 78x13.7 78x15 64x13.8 84x15.3 W 99 i 99 1 ??1/2 85 1 85 IOff/2 112 112 118 118 122 122 135 135 94 95 95 101 101 , 103 103 114 114 7500 ! 7900 6300 6700 8300 10600 11700 12900 14000 . 16300 17900 19800 i 21300 22600 24700 28400 31300 7100 8800 9600 10600 1 11500 | 13700 15100 16600 i 17800 1 19200 21100 24300 27000 . B o ile r N o .................. Rated Capacity,* Steam, sq. Burning Coal................... Oil, Gas or Stoker Fired Width and Length..........in Over-all Height........ Height of W^ter L in e .. . . ; . . . .. . . .Approximate Weight: ; Coal Burning .Oil Burning.. ....... ......... Jacket, Crated, Add........... v . '5 m gaf<io ss Ei-ss as- m(olmons._S2 SSs o--o--^*.t(0JOjZNTScsotonf*m S8&83 748 742 743 745 746 747 1 SSis:SS gSg sas m (A SSgrSS 88;q Boilers, Steel m. .. : :-S.S-S -iii at : : h : : * s-io 2 *s Boilers, Steel Lookout Boiler & Mfg. Company Successors to the HEGGIE SIMPLEX BOILER CO. Joliet, Illinois Chattanooga, Tennessee RBO. U. 8. PAT. OFFICE Representatives In Principal Cities REG. U S. PAT. OFFICE STANDARD SERIES LOOKOUT HEGGIE-SIMPLEX STEEL HEATING BOILERS Length of Boiler, Overall, Inches Height of Base. Inches Height of Water Line, on Base, Inches Steam Liberating Area, Sq. Ft. Water Capacity Full, Gallons 1Size of Steam | Outlet, Inches Size of Return Opening. Inches Diameter of Stack, Inches Boiler Covering 1 Required. Sq. Ft. | 15-Lb. Steam Pressure Steel Plate Welded Joints A.S.M.E. Construction 30-Lb. Water Pressure S'e-im H-iltr A uemhty Smokeless Arch Type For Burning Any Solid Pud STANDARD SERIES SPECIFICATIONS Direct Draft Type . Mechanical Fired Type Smokeless Direct Mechanical Arch Type Draft Type Fired Type Catalog Number Steam Boiler Steam Rating Sq. Ft. (SJH3.I.) Catalog Number Steam Boiler o h -3=5 S* Z3* ll Elf Eu Ocn JU 134A 1690 334A 1690 734A 2060 121 134C 2110 334C 2110 734C 2570 151 134K 2530 334E 2530 734E 3080 181 140A 3110 340A 3110 740A 3770 222 I40B 3500 340B 3500 740B 4250 250 140D 4120 340D 4120 740D 5000 294 140E 4500 340E 4500 740E 5470 322 147A 5000 347A 5000 747A 6080 358 147B 5490 347B 5490 747B 6660 392 147C 5960 347C 5960 747C 7740 426 152A 6500 352A 6500 752A 7890 464 I52B 7000 352B 7000 752B 8500 500 152C 7520 352C 7520 752C 9130 537 I52D 8040 352D 8040 -752D 9760 574 157A 9100 357A 9100 757A 11050 650 157C 10420 357C 10420 757C 12650 744 157D 11070 357D 11070 757 D 13450 791 163A 12500 363A 12500 763A 15180 894 163B 13360 363B 13360 763B 16770 954 163C 14200 363C 14200 763G 17740 1014 163D 15000 363D 15000 763D 18270 1074 170A 16020 370A 16020 770A 19450 1144 I70B 17020 370B 17020 770B 20670 1216 170C 178A 18030 20IXM1 370C 378A 2108000300 770G 778A 21900 74790 1288 1429 178C 22390 378C 22390 778C 27180 1599 184A 25000 384A 25000 784A 30360 1786 1840 28010 384C 28010 784C 34070 2001 184E 31010 384E 31010 784E 37660 2215 184G 34010 384G 34010 784G 41290 2429 Heating Surface Sq. Ft. (S M B A .) Grate 1 Area | Square Feet TmbOS fIofsl-gc `o `S" S 8 ll rs-S t*J5 Xr so 8 2 34 67% 12 72 10.5 34 79Vi 12 72 10.4 34 91% 12 72 12.4 40 80Vi 12 79 13,7 40 86Vi 12 79 13 7 40 98/i 12 79 11 7 40 104% 12 79 14.7 47 .101 Vi 12 86 16,5 47 107V. 12 86 16.5 47 1131/4 12 86 18.6 52 103% 12 91 18.6 52 109% 12 91 20.7 52 115% 12 91 20.7 52 121% 12 91 22.9 57 115% 12 97 75 2 57 127% 12 97 25,2 57 133% 12 97 28.1 63 123% 15 108 28.1 63 129% 15 108 28.1 63 135% 15 108 30.6 63 141% 15 108 31.0 70 129% 15 116 31.0 70 139/4 15 116 33,9 70 141% 15 116 35.0 78 135% 15 126 38 2 78 147% 15 126 38.0 84 141% 15 132 41 3 84 153% 15 132 44,8 .84 165% 15 132 44.8 84 177% 15 132 67V. 9.8 171 62% 12.3 214 62% 14.8 257 69% 13.9 280 69% 15.3 308 69% 18.1 364 69% 19.5 392 77721%A 22.3 24.0 47ft 514 72% 25.8 552 78% 23.3 551 78% 25.1 5% 78% 26.9 641 78% 28.8 686 81% 30.9 753 81% 35.1 858 81% 37.2 910 93 34.9 953 93 37.1 1014 93 39.3 1076 93 41.5 1137 %% 43.6 1269 96V. 46.2 1347 96% 48.8 1423 106% 47.9 1524 106% 53.9 1751 113 52.9 1831 113 58.9 2042 113 64.9 2255 113 70.9 2467 6 6 6 6 6 6 6 8 8 8 8 8 8 8 8 8 8 10 10 10 10 10 10 10 10 10 10 10 10 10 3 18 66 3 18 78 3 18 89 3 20 92 3 20 98 3 20 110 3 20 116 4 22 125 4 22 133 4 22 141 4 24 136 4 24 144 4 24 152 4 24 160 4 27 167 4 27 184 4 27 193 5 30 19/ 5 30 206 5 30 215 5 33 224 5 33 230 5 33 240 5 36 250 5 36 258 5 36 281 5 40 291 5 40 314 5 40 337 5 42 361 To determine S.H.B.I. Ratines of Hot Water Heating Boilers, add 60 per cent to corresponding steam boiler rating. 886 Lookout Boiler & Mfg. Co. Boilers, Sice! . RESIDENCE SERIES LOOKOUT HEGGIE-SIMPLEX STEEL HEATING BOILERS Steel Plate Welded Joints 15-Lb. Steam Working Pressure A.S.M.E. Construction 30-Lb. Water Working Pressure Direct Draft Type for Hand Firing any Solid Fuel Mechanical Fired Type for Oil, Gas, or Stoker Steam Boiler Auembly with Jacket For Burning Any Solid Fuel RESIDENCE SERIES (Double Pass--2 In. Tubes) SPECIFICATIONS Jacketed and without Jacket Direct Draft Type Mechanical Fired Type Direct .. Mechanical Draft Type Fired Type Catalog Number i Steam Boiler 11 Catalog Number Steam Boiler Steam Rating Sq. Ft. (S.H3.I.) Heating Surface Sq. Ft. (S.HJ3.L) Grate Area Square Feet Width of Boiler, Inches Length of Boiler, Overall, Inches Height of Base, Inches Height of Boiler on Base, Inches Height of Water Line, on Base, Inches Steam Liberating Area, Sq. Ft. Water Capacity Full, Cations Steam Space Cu. Ft. Size of Steam Outlet, Inches Size of Return Opening, Inches Size of Water Heater Openings Diameter of Stack. Inches 41 i 2SJ1 2SJ2 2SJ3 2SJ4 2SJ5 2SJ6 2SJ7 2SJ8 2SJ9 2SJ10 tncJT 370 2SCJ1 510 2SCJ2 670 2SGJ3 800 2SCJ4 950 2SCJ5 1110 2SCJ6 1300 2SCJ7 1480 2SCJ8 1620 2SCJ9 1830 2SCJ10 540 32 2.6 680 4(1 3.5 820 48 4.3 970 57 5.1 1160 68 5.4 1340 79 6.0 1580 93 7.0 1800 106 7.8 1970 116 7.9 2230 131 9.0 *3 il 24 34% 12 24 40% 12 24 45% 12 24 53(5 12 27 . 47% 12 27 53% 12 27 60% 12 27 66% 12 30 60% 12 30 66% 12 56 48 3.8 37 56 48 4.8 48 56 48 5.8 60 56 48 6.8 71 65 55% 6.6 103 65 55% 7.7 122 65 55% 8.9 143 65 55% 10.0 163 72 61 10.1 175 72 61 11.3 199 1.8 3 2.3 3 2.8 3 3.3 3 3.8 4 4.5 4 5.1 4 3.8 4 6,7 5 7.6 5 3 % 10 30 3 i% 10 30 3 i% 10 30 3 i% 10 30 4 i% 12 40 4 i% 12- 40 4 i% 12 40 4 1% 12 40 5 1% 14 50 5 i% 14 50 To determine S.H.B.I. Ratings of Hot Water Heating Boilers, add 60 per cent to corresponding steam boiler ratings. .' ; In addition to the STANDARD SERIES and RESIDENCE SERIES of Steel Heating Boilers, we make the following: HIGH FIREBOX SERIES--Mechanical Fired Type; Specifications given in Bulletin No. 112. P. 0. SERIES PORTABLE FIRE BOX BOILERS-KSingb Pass)--Down-draft Water-Grate Type--Direct Draft Type-- Mechanical Fired Type.. Specifications given in Bulletin No. 117. Fi\0. SERIES PORTABLE FIREBOX B0ILERS-(Double Pass)--Down-draft Water-Grate Type--Direct Draft Type--Mechanical Fired Type. Specifications given in Bulletin No. 118. `. REFUSE BURNING WATER HEATERS-jj^Direct Draft Type...Specifications given in Bulletin No. 119. 887 Boilers, Steel Waterfilm Boilers . Incorporated ' 154 Ogden Avenue, Jersey City, N. J., U. S. A. BOILERS DESIGNED AND BUILT FOR AUTOMATIC FIRING Boiler No...................................................... 2 3 4 5 Recommended Load Square Feet E. D. R. Steam I Water Steam I Water Steam 1 Water Steam 1 Water Pickup included in these ratings............... 500' | 800' 800' I 1280' 1100' I 1760' 1400' | 2240' Guaranteed B.T.U....................................... 120,000 192.000 264.000 336.000 Maximum Firing Rate G.P.H..................... 1.65 gal to 2 gal 2 gal to 2Vz gal 21/? gal to 5 gal I'/z gal to . 4 gal DE LUXE SERIES completely jacketed with either short to cover boiler only, or long to cover boiler, burner and domestic hot water tank. SECTIONAL SERIES Single Series Recommended No. Load EJD.R. Steam Water Guaranteed . B.T.U. No. Recommended Load E.D.R. . Steam Water Guaranteed 1 B.T.U. 1-5 1-6 1-7 1-8 1-9 1-10 1-11 1,250 2,000 1,500 ' 2,400 1,750 2,800 2,000 3,200 2,250 3,600 2,500 4,000 ` 2,750 4,400 _ 330,000 390,000 450,000 5l0;000 570,000 630,000 690,000 1-12 1-13 1-14 1-15 1-16 1-17 * . 1-18 3,000 3.250 3,500 3,750 4,000 4,250 4.500 4,800 5,200 5,600 6,000 6,400 6,800 7,200 750,000 810,000 870,000 930,000 990,000 1,050,000 1,110,000 2-8 2-9 2-10 2-11 2-12 2-13 2-14 2-15 2-16 2-17 2-18 2-19 2-20 2-21 2-22 2-23 2-24 4,000 4,500 5,000 5,500 6,000 . 6,500 7,000 7,500 8,000 8,500 9,000 9,500 10,000 10,500 11,000 11,500 12,000 6,400 7,200 8,000 8,800 9,600 10,400. 11,200 12,000 12,800 13,600 14,400 15,200 16,000 .16,800 17,600 18,400 .19,200. Double Series 990,000 1,110,000 1,230,000 , 1,350,000 1,470,000 1,590,000 1,710,000 1,830,000 1,950,000 .2,070,000 2,190,000 2,310,000 2,430,000 2,550,000 2.670,000 2,790,000 2,910,000 2-25 2-26 2-27 2-28 2-29 2-30 2-31 2-32 2-33 2-34 2-35 2-36 2-37 2-38 2-39 2-40 2-41 . - 12,500 13,000 13,500 14,000 14,500 15,000 15,500 16.000 16,500 17,000 17,500 18,000 18,500 19,000 19,500 20.000 20,500 20,000 20,800 21,600 22,400 23,200 24,000 24,800 25,600 26,400 27,200 28,000 28,800 29.600 30,400 31,200 32.000 . 32,800 3,030,000 3,150,000 3,270,000 3,390,000 3,510,000 3,630,000 3.750,000 3,870,000 3.990,000 . 4,110,000 4.230,000 4,350,000 4,470,000 5,630,000 5.750,000 5,870,000 5,990,000 ` 888 International Heating & Ventilating Exposition THE AIR CONDITIONING EXPOSITION Permanent Address--Grand Central Palace, New York, N. Y. EXPOSITIONS HELD The first in Philadelphia, 19T30h.e secon^d in rC\leve- ' land, 1932. The third in New York, 1934. .. The fourth Exposition will occur in Chicago, Jan uary27-31, 1936. Subsequent Expositions will be held on alternate, even numbered years. These are held coincident with the Annual Meeting of the American Society of Heating and Venti andlating Engineers are directed by the Inter national Exposition Company, under the auspices of the A.S.H.V.E. EXHIBITORS Comprise leading firms in each phase of the industry: number has varied from 150 to 275 exhibitors. - , EXHIBITS These range from and comprise all the .types of articles discussed or advertised in this qqpy of The A.S.H.V.E. Guide. -1., The Combustion Group: Furnaces, burners (oil and gas), grates, stokers, boilers, radiators (various . types), refractories and auxiliaries. 2. The Hydraulic Group: Water feeders, water heaters, pumps, traps, valves, piping, fittings, expan sion joints, pipe hangers, etc. 3. The Steam Heating Group: Vapor heating and steam specialties. 4. Air Group: Warm Air furnaces and stoves, registers and grilles, cooling towers, air filters, motors, fans, blowers,conditioning equipment, venti lators (room and industrial types), unit heaters, etc. 5. Control Group: Instruments of pre cision for indicating, controlling or re cording temperature, pressure, volume, time, flow, draft or any other function to be measured. 6. Refrigerating: Compressors, con densers, cooling apparatus,(Contingent apparatus and refrigerants'for homes, factories, railroads, etc. 1 7. Central Heating: Apparatus and materials especially designed or adap ted to the use of central heating and central heating station supplies. 8. Insulating: Struct ural insulators (re fractory and cellulose materials), asbestos, magnesia clays and combinations thereof, _pipe and conduit c o v e ring, etc., weather-stripping, etc. 9. The Miscellaneous Group: Electric Heaters, boil er and pipe repair al loys, liquids and com pounds, etc., which are not included above. 10. Machinery and General Equip ment. VISITOR ATTENDANCE Comprises a registered attendance in vited to the exposition and includes: (Figures are 1934 analysis) Industries Governmental................................................................... 186 Distributional Channels , . Contractors. Dealers, Jobbers. Supply Houses. 32 classifications....................-......... 5998 Home Owners........................................................... 414 Industrial Users, 49 classifications..................- 3428 Professional and Service Organizations, 23 classifications....................................................... 2017 Public Utilities.............................................................. 922 Real Estate Management and Operation, 10 classifications'..........;.................................-- 581 Educational Institutions......i................................ 303 Miscellaneous....................... 1043 Total................................................................. 15.256 Occupations Executive (44 titles).... ......................................... 6850 Construction (16 titles and trades)................. 1022 Operation (44 titles and trades)........................ 2014 Technical (64 titles).............................. -.............. , 2044 Not Classified including Educators. Pub- , lishers. Home Owners, etc............................ 2222 Total................. :...............................................15,256 These visitors came from 704 cities and towns in 37 States of the United States and 25 cities and towns in 11 foreign countries. 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 edu cational institution which biennially brings together the research developments and improvements in equipment and materials^ Burners (Oil) Delco Appliance Corporation Subsidiary of General Motors Rochester, N. Y. Delco-Heat Conversion-Burners . Delco-Heat represents a distinct achieve ment in the automatic heating industry. It is backed by the years of study, research and experience gained in perfecting the combustion of liquid fuels. Delco-Heat incorporates many new, practical and economical features in design, operation and manufacture. Delco-Heat possesses all the essential requirements which are expected in modern heating apparatus. The Delco-Heat Models listed and illu strated, furnish a range of burner sizes which are adapted to the varied require ments of the small home, the large apart ment house or commercial and industrial installations. The several sizes differ somewhat in design due to service require ments but each size is built of the same quality material and has the same, skilled workmanship in its construction. for larger installations and is appropriate for small apartments and stores and com mercial buildings. Delco-Heat Burners for Commercial Use Delco-Heat equipment is economical to install and operate, simple in construction and design, quiet in use and has years of proven performance in commercial build ings of every character. I f you have a special heating problem or require specific information not found here, there is a Delco-Heat representative nearby. The Engineering Department is-also at your service and if you so prefer, complete specifications and recommendations will be made, if the plans and special infor mation desired are sent to the Sales Engineering Division, Delco' Appliance Corp., Rochester, N. Y. ~ Delco-Heat Models DX and DX-12 Delco-H.eat Model DX: Capacity-- Steam, 900 sq-ft; Hot Water, 1440 sq ft. Efficient burner for. small home or large residential use. It burns efficiently low cost domestic fuel oil. It is-fuliy equipped with all necessary controls for complete automatic' operation and carries the Underwriters' label. Ignition is by inter mittent electric spark. ' Delco-Heat Model D-12: Steam, 2330 sq ft; Hot Water, 3725 sq ft. Is intended \ . Delco-Heat Models D-34 and D-44 Model D-34: Capacity--Steam, 5400 sq ft; Hot Water, 8600-sq ft. Burners adapted for commercial and industrial installations. Burns either No. 3 or No. 4 Fuel Oil with capacity of from 7.0 to 16.5 gals per hour. Ignition is by intermittent spark. Model D-44: Capacity--Steam, 10,000 sq ft; Hot Water, 10,000 sq ft. It bums either No. 3 or No. 4 Fuel Oil with ca pacity of from 15.0 to 30.0. gals per hour. Ignition is by intermittent spark. See also Pages 8S5 and 876 890 Burners (Oil) Electrol Incorporated FINE OIL HEATING EQUIPMENT EXCLUSIVELY SINCE 1918 934 Main Avenue, Clifton, N. J. Conversion Burners, Boiler-Burner Units, Air Conditioners Electrol-Kewanee Heating Unit QaM.JUKlectrfc ' ELECTROL .OIL BURNER Electrol-American Heating Unit A complete boiler-burner unit consisting of (1) exclusive design, horizontal, welded steel firetube boiler; (2) Electrol oil burner mechanism; and (3) domestic water heater. Induced draft. Guaranteed minimum 80 per cent over-all efficiency. Low stack temperature. Integral flame, low water and limit controls. Attractive soundinsulated jacket. Burns heavy furnace oil. Simple, automatic. A complete boiler-burner unit specially designed for small homes. 5- or 7-section, cast iron boiler of special construction, oil burning mechanism and domestic water heater all designed and built as one unit. Integral flame, low water and limit con trols. Positive air adjustment at burner head. Burns heavy furnace oil. Simple, quiet, automatic. .80 per cent over-all efficiency. Unit Cap. E.DJL Steam Cal. Oil lr Cals. D.H.W. Three Hours Over-all Dimensions. In. L wH E-K5 750 1.6 50 471/, 34 55% EJC 10 1250 2.7 80 OBYl 34 55'/. E4C 15 1750 3.75 100 75 34 55'/4 Unit Cap. E.D.R. Steam Gal. CHI Hour D.H.W. Three Hours 3ver-all Dimensions. In. L WH EA 4 600 E-A4A 825 1.27 1.74 50 50 3% 26 26 Electrol Oil Burner Famous for nearly 20 years for depen dable, economical operation in any boiler or furnace. Curved air chamber produces rotating air and ball-shaped flame. Ex clusive Master Control safety. Con tinuous electric ignition. Cut-off valve at nozzle. New parts fit any existing models --eliminating obsolescence. Burns heavy furnace oil. Simple, fully automatic. Summer-Winter Dom. H. W. with indirect heater. Electrol Air Conditioner Specially balanced for fully, automatic operation with Electrol boiler-burner units or steam or hot water boilers with con version burners. Provides heating, hu midification, ventilation, air cleansing and circulation and, if required, summer cool ing and dehumidification. Built in three sizes. Furnishes 6 to 7 air changes per hour. Washable cloth filters. Low velocity air circulation, eliminating drafts. Gal. Oil Model per Hour Sizes Min. Max. Capacity E.D.R. Steam TC 1.3 3'A 200-1100 11 1.3 2(5 200-800* TU 2 I'M 12 24 600-2800 2500-10,000 Electrol Conversion Oil Burners should be selected to heat a boiler to its full rated capacity, regardless of the load that may be connected to the boiler. Standard Equipment with the Model TJ is 1X40 rpm motor. With 1725 rpm motor, capacity is same as model TC. 891 Electrol Direct- Fired Fan Furnace Unit Provides either or both complete winter and summer air con ditioning. Heating, humidification, air cleansing and circula tion, plus .cooling and dehumidification. Tested efficient design; competitively priced. Sizes to handle 112,000 to 254,000 Btu--1,000 to 2,500 cfm. Burners (Oil) Norge Division Borg-Warner Corporation 606-670 E. Woodbridge Street, Detroit, Michigan Norge Whirlator Oil Burner Service through franchised distributors and dealers throughout the United States. Norge Whirlator Oil Burner is a "guntype" burner built in six sizes, Model 8, handles 800 sq ft of steam radiation or its equivalent; Model N-18, handles 1800 sq ft; Model N-28, 2800 sq ft; Model N-38, handles 3800 sq ft; Model N-68, handles 6800 sq ft; Model N-88, handles 8800 sq ft. The "Whirlator" is a patented design of multiple vanes, completely rotating entire mass of air in a smooth even move ment, perfect ad-mixture with oil in correct proportion for high combustion efficiency. -Nozzle of latest improved design will atomize 28-30 Baume, known as No. 3 A.O.B.A. specifications, or lighter oils, with a fog-like spray. Motors--(Model N-8) Split Phase, 110 volts, 60 cycle, alternating current, 1750 rpm. Small current consumption. Model N-8, 3do hp motor--Model N-18, If, hp, Model N-28, K hp. . Larger models are powered in pro portion. . Ignition--Two-pole transformer, hot spark, designed for heavy duty, minimum temperature rise, low input, shielded secondaries, built-in radio interference eliminator. Tested for maximum break down of 15,000 volts. Controls -- Minneapolis - Honeywell Series 10, low voltage room thermostat, type R-l 17-3 Protectoclay (stock mounted) or combustion safety device and boiler or limit control (either high or low voltage, as desired). . Pump--Rotary type, connected direct ly through flexible spring coupling to motor shaft. Simple and quiet. Fan -- Fabricated light aluminum, strong and accurately balanced. Mounted on motor shaft with no intermediate con nections. Strainers--A series of two strainers used, with ample capacity to remove dirt and sediment from oil. - Accessibility--Fan or blower housing, and inspection cover in one light-weight casting. When removed exposes entire interior mechanism. Legs--Three legs provide a sturdy mounting with easy adjustability. Approvals--Listed as standard by Underwriters' Laboratories, and approved by all leading state and municipal safety boards of fire departments. See also Pages 830 and 847 892 Burners (Oil) Williams Oil-O-Matic Heating Corporation . Bloomington, Illinois Manufacturers of Automatic and Manually Controlled Fuel Oil Burners . Service to Architects and Builders ' Chicago, III., 641 N. Michigan Avenue New York, N. Y., 1231 Graybar Building . For Williams Air Conditioning Equipment`''and Ice-O-Matic Refrigeration Equipment, see File Index . A Complete Line Williams Oil - O - Matic offers a complete line of oil heating equipment; five Oil- O-Matic burner models--a genuine Williams Oil-O-Matic of ideal capacity for every size and type of house, . for every apartment, public building or commercial structure. New complete boiler-burner units; a new and revolutionary type of oil-burning automatic water heater; and a new oil burning range burner for heavy duty ranges are available. . 70,000 B.t.u.'s when using hot air fur nace rat ings. 24 sq. ft. steam boiler heating surface (or 2.2 H.P.). For exact detail data, see Oil-OMatic Installation and Service Manual. Heating Capacities of the Various Williams Oil-O-Matic Burners Domestici t s ? Length I W id th Height ' H.P. I Model Gals. Fuel Oil for Oper ating Hour 2 ol 'os Min. Max. K-150 K*>3 K-7 J- 800 jj 115 30* 145 175 13* 255 45* 295 50* 14V,' 15V,' 1/10 1750 w \r l/i<] 1750 it'/,' 23* 33* lav,* 2225** 111 //25 1750 1/50 1750 '/z \ 3 7 15 m 3 7 15 25 a Standard Draft Pipe 18 in. 12 in. length Draft _ Pipe optional. ` Standard electric current is 60-cycle, 110 volt. In case odd frequency motors are used, the maxi mum capacity of the burner will be reduced-in proportion to the R.P.M. of the motor. The minimum capacity remains the same. - ` Water Heaters WHA* WHBf WHCJ 600 885 1380 58* 8785** 23* 25* 29* 28* 28* 34* 111///111000 1750 1750 1/50 1 '/z y2 1.0 lJ/4 Output: 90 F rise, 60 gal. per hour. fOutput: 90 F rise, 120 gal. per hour. JOutput: 90 F rise, 210 gal. per hour. . How to Decide Size of Burner For low pres sure Domestic Boifi^s, one gallon 'of fuel oil per hour (140,000 B.t.u.'s) is re quired for ap proximately: 300 sq. ft. of steam radiation or its equivalent. 480 sq. ft. of hot water radiation or its equivalent. Oil-O-Matic Hot Water Supply A new efficient hotlwater supply unit made in 3 sizes covering ordinary home use, large home or commercial use.yand heavy duty requirements. The entire ap paratus--including Oil-O-Matic oil burner, combustion chamber, water reservoir, and all automatic controls--is combined in one compact unit. Tank being horizontal in stead of vertical, permits the use of a unique triple flame travel. Water heater is also available with one (or more) room heating radiators as illustrated. Horizontal Boiler-Burner Unit Horizontal boiler-burner unit design greatly increases efficiency. Built with A.S.M.E. code tanks, galvanized of not galvanized. Complete with full automatic controls. Suitable for hot water, vapor or vacuum heating plants, and the largest size unit suitable for steam plants. Underwriters' Listing Oil-O-Matic burners are listed as standard by the National Board of Fire Underwriters' to bum oils conforming to commercial, standard specifications for Nos. 1, 2 and 3 fuel oil having a viscosity of not more than 70 sec. (Saybolt- Universal at 100 F). Each burner carries the Underwriters' label. - Range Burners New type Oil-O-Matic range burner burns low-cost fuel oil. Economical and efficient. Designed for heavy duty ranges. Engineering Service . is available to architects. See A.I.A., File No. 30-6-1. See also Page 848 893 Coal Burners, Automatic Iron Fireman Manufacturing Company Automatic Coal Burners Portland, Oregon Factories: Portland, Orb.; Cleveland, Ohio;, Toronto, Canada Retail Branches or Subsidiaries Chicago, III.. Milwaukee, Wis. St. Louis, Mo. New York, N. Y. Montreal, Can. Dealers In Principal Cities and Towns in the United States and Canada Representation in numerous foreign countries. IRON FIREMAN Automatic Coal Burners "Forced Underfiring" Principle --Iron Fireman "Forced Underfiring" is based on the scientific principle of feeding fuel to the fire from below, under forced draft. From the con veyor screw coal enters the firebox under the fire and is gradually forced up ward into the flame. As the coal ap proaches the fire, it is gradually heated. The volatile gases are distilled off in the presence of an excess of oxygen and are thoroughly ignited while passing through the incandescent fuel bed. This insures complete combustion. The ash is fused into clinkers which are easily removed. Advantages--Iron Fireman saves money and in creases heating plant efficiency in four major ways: (1) Cuts fuel costs; (2) Reduces labor costs; (3) Provides steady, Typical Installation Down even heat or Draft Firebox Boiler power; (4) Elimi- , nates the smoke nuisance. Installation and Sizes--Iron Fireman is made in a range of hopper and bin-feed sizes for commercial heating and power boilers up to 300 b.h.p. and also for homes. It can be installed quickly in practically any solid fuel boiler or furnace, old or new. Machines are shipped complete from the factory. All parts are standard and interchangeable. Features of Design and Construc tion--Construction and operation of the Iron Fireman are characterized by sim- plicity throughout. Outstanding fea tures of design and construction, are: (1) Pressed steel construction. (2) Special patented transmission--three speeds and neutral. Gears run in bath of oil. (3) Electric motor--standard make. (4) V-belt drive. (5) Safety shear pin protects mechanism from damage. (6) Quiet bail bearing fan supplying forced draft to fire. (7) Automatic fire banking damper--conserves fuel and holds fire in proper condition when stoker is idle. (8) Positive pneumatic fume eliminator--an auxiliary air supply that insures positive movement of all gases through the fire. (9) Volumeter that supplies exactly the amount of air needed for perfect com bustion regardless ' of fuel bed con ditions or type of coal used. (10) Sectional retort especially design ed to allow for heat expansion.. (11) Dead plates of heavy iron and ribbed. (12) Sec tional, self-clean ing tuyere blocks. Typical Installation Four Drum Water Tube Boiler (13) Conveyor screw cast of special Jron Fireman alloy steel from one-piece pattern. (14) Automatic electric controls designed for and used exclusively on Irpn Fireman. Automatic Controls--Iron Fireman starts and stops at the command of sensi tive, accurate automatic controls. Direct ing controls govern stoker operation according to demands of time, tempera- Iron Fireman Manufacturing Company Coal Burners, Automatic Domestic Installation--Bin-Feed Model ture, or pressure. An example of the superiority of Iron Fireman directing con trols is the "Syncro-Stat " which provides automatic control of day and night tem perature. Other directing controls include pressure regulators, hot water and furnace regulators, and the "Timetactor," a device which runs the Iron Fireman during pre determined intervals in order to keep the fire alive during mild weather. The most important unit of the oper ating control system is the motor-driven . relay switch. This device starts and stops .the stoker motor at the com mand of the - Syncro-Stat or other directing controls. In the case of the larger stokers a magnetic Typical Inslallation Operating switch Cast Iron Boiler works in conjunc tion with the relay switch. Iron Fireman for Homes--The Iron Fireman residential model employs "Forced Underfiring" principle-the same as larger machines, with simplified operation. Can be recommended for any steam, hot water, vacuum, or warm air furnace. Quickly installed. Hopper and bin- feed models for both bituminous and anthracite coal. Anthracite models have been tested and ap proved by The Anthracite Insti tute. . Typical Installation Domestic Boiler ENGINEERING SERVICE The Iron Fireman organization is nationwide. Trained men--backed by one of the largest manufacturing organiza tions in the field--are at your service to help you with the experience and practical heating information gained through servic ing thousands of boiler rooms and heating plants in all parts of the country. . Any Iron Fireman engineer will gladly call and submit any additional informa tion requested. . CATALOG AND INFORMATION Catalogs give full information about the Iron Fireman. Descriptive folders give special data about installation in particular types of industries and in homes. Secure them by addressing the factory or any Iron Fireman representative. Iron Fireman in Operation in Horizontal Return Tubular Boiler, Low Bridge Wall 894 Commercial Model--For Heal or Power Industrial "Poweram" Model--For Heal or Power Combustion Control (Automatic) Henry Furnace & Foundry Co. Cleveland, Ohio Miles Furnace Fan Division MILES FORCED DRAFT AND CONTROL UNIT MILES COMBUSTION, PRESSURE AND TEMPERA TURE CONTROL UNIT Reduces costs, maintains uni form steam pressure and tem perature and increases efficiency. Permits burning of cheaper grades of coal, slack, run of mine, buckwheat and rice. Miles Combustion, Pressure and Tem perature Control Unit is first, a forced draft unit, consisting of motor driven fan and pivoted damper actuated by steam pressure in the boiler, made in seven sizes to deliver air volumes as required and capable of overcoming various amounts of resistance. Second, it is an air pressure and control unit which effects an instant and minute control of the air volume and static pressure in response to pre-determined steam pressure or water tempera ture by means of the Miles Patented Air and Pressure Control Unit. A pivoted shut-off damper yields to air pressure from the fan to an open position, and yields also to pressure due to steam or water temperature to a closed position. These counteracting pressures actuate the damper to the exact position which con trols air volume and pressure under the grates and this in turn controls the fire. So delicate is it in operation that the steam pressure will maintain a steady heating load with a variation in pressure of not to exceed two ounces over an extended period. When a Miles Combustion, Pressure and Temperature Con trol Unit is installed, the chimney is eliminated as a draft producing factor. It becomes merely a vehicle for carrying off the products of combustion. Automatic control and me chanical force supply the correct amount of air for any and every condition. The Miles Control Unit may be installed on either side of boiler or furnace or in the rear. Only the Miles forced draft control has the patented graduated air supply feature which coordinates steam pressure and air volume to produce the required combus tion. This unique device is in action at all times when heat is required, and supplies air constantly so that ashes are kept cooled below fusing point--hence no clinkers. Write for complete information. DATA SHEET Miles Draft Control Unit for Steam and Hot Water Boilers and Warm Air Furnaces No. of Unit Steam Radiation H.P. of Motor Anthracite Buckwheat Anthracite Rice Bit. Nut Bit. Slack Warm Furnace Btu Capacity Self-contained 3-B 1/50 670 3-HW 4-A 4-B 5-A 1111////21110500 1330 1850 3500 4150 665---BAB 1/3 - 8000 11//24 9000 13300 1500000 1380 2625+ 3100 6000+ 107,025000+ -167,000 332,000 462,000 875,000 21,040,000 ,000,000 2,250,000 3,320,000 Miles Combustion, Pres sure and Temperature Mths Combustion, Pres sure and Temperature See also Page 848 896 Over Fifty Years In Business Expansion Joints American District Steam Company North Tonawanda.N.Y STEAM DISTRIBUTION EQUIPMENT Branches and Agents in Principal Cities ADSCO Piston-Ring Expansion Joint ADSCO Packless Expansion Joint, U-Ring Type The ADSCO Piston-Ring Expansion Joint can be packed under full operating pressure without interruption to service. The piston rings hold the line pressure during the repacking operation. The ADSCO Piston-Ring Expansion Joint is available in all sizes in single and double slip design; semi-steel or cast steel bodies for all pressures up to 400 lb. and tempera tures to 750 F., with flanged ends or ends beveled for welding. Write for Bulletin No. 35-15. ADSCO Rotary Condensation Meter The ADSCO Packless Expansion Joint, U-Ring Type is based on an entirely new principle for controlling pipe expansion. The expansion element is a series of die-, formed "U-Rings" of stainless alloy steel, welded without transverse seams. The joint is installed with the element com pressed. Under full operating conditions, the element is in a neutral position, free from strain. Available with all steel body, fully enclosed element, for pressures to 400 lb. and 800 F., with flanged ends or ends beveled for welding. Write for Bulletin No. 35-50. ADSCO Vertical Steam Trap For measuring the steam condensation of a heating system or heating equipment. Used by District Heating Companies as a basis of charge for steam sold--institu tional groups for steam cost distribution-- and industrial firms for steam consumed in process work. Accurate within 1 per cent. Dependable. Compact. Reads directly in pounds of condensed steam. Furnished with semi-steel or aluminum body and cover in seven sizes; 250, 500, 750, 1500, 3000, 6000 -and 12,000 lb. capacity per hour. Write for Bulletin No. 35-80. The ADSCO Vertical Steam Trap, is a continuous flow, float type, trap with direct vertical inlet and outlet connections and an optional 90 deg. inlet connection. All working parts are mounted on the cover, all piping connections on the body. It has a reversible valve and reversible, seat, giving a double life trap at no extra cost. The cover can be removed quickly and the mechanism serviced easily without disturbing the piping. Write for Bulletin No. 35-85A. 897 Expansion Joints E. B. Badger & Sons Co. 63-75 Pitts Street, Engineers and Manufacturers Boston, Mass. N. Y. Office. 271 Madison Avenue Offices in Principal Cities PRODUCTS and SERVICES--Corrugated Copper Expansion Joints, Pipe Bends, Chemical Apparatus, Copper and Sheet Metal Work, Copper Boilers and Hot Water Tanks; Engineers on Process Work BADGER DIRECTED FLEXING EXPANSION JOINTS Since the Badger Corrugated Type of Expansion Joint was first placed on the market more than 40 years ago, several important improvements have been in corporated in this joint by E. B. Badger & Sons Co., Engineers, each adding to its life and utility. . 1. Adoption of equalizing rings. 2. Machine method of making uniform corrugations. 3. Use of seamless copper tubes. 4. Improved machine method of manu facture resulting in minimum forming stresses. 5. Monel sleeves for protection against superheated steam. 6. Welding end joints. 7. Adoption of scientific heat treatment. 8. Use of special deoxidized copper. 9. Directed Flexing. Advantages of the Corrugated Joint Eliminates packing; avoids steam losses. No Servicing, Compact, Accessible, No Manholes needed. Directed Flexing This feature, exclusive with joints made by E. B. Badger & Sons Co., has brought about a marked increase in the life of the corrugated type of joint. Corrugations are "all-curved" and when flexing actually wrap and un- ' wrap them selves in an un dulating move ment about the' eq ua 1 i z i n-g rings. The movement is progressively controlled as well as limited. Original tests and a eft u a 1 service have proved thor oughly the soundness of this new design of corrugated expansion joint. Different Types Available Both flanged end and welding end joints are available from 3 in. (welding) and 4 in. (flanged) up. Single or double joints with or without service outlets. All joints can be equipped with telescoping monel metal sleeves to protect against superheated steam. We can furnish flanged joints less than 4 in. in size by fitting the 4-in. units with companion flanges, bolts and gaskets tapped to the desire'd size. Fitted with alignment bars on the 4 and 5*in. sizes. Choice of standard or extra heavy flanges. From 1 to 3-in. expansion, inclusive. On 6 in. pipe and larger, no alignment bar is used. Standard 125 lb or extra heavy 250 lb flanges as required. From 1 to 4-ii). expansion, inclusive. Welding Types For use with both saturated and super heated steam. Single type from 3 in. up, to take cafe of 1 in. expansion or more. Pipe nipples welded directly into pipe line. Double units for 2 in. expansion or more. Equipped with service outlets if desired. Complete units furnished, mounted on base plate, with anchor and guides. Single and Multiple Corrugated^ Expansion Joints for Low Pressure For use between turbine or engine exhausts and condenser or on low pressure lines. Excellent for absorbing shock and vibra tion. Flanges in round, oval or rectangular shapes. Guaranteed up to 30 lb pressure. 898 American Machine and Metals Manufacturing Corp. DeBothezat Division Executive and Sales Offices: 100 Sixth Ave., New York, N. Y. Factory: TROY. N. Y. Branch Offices and Representatives In All Principal Cities . Fans and Blowers are guaranteed to have non-overload ing power characteristics. Complete operating safety under varying working conditions is assured. Disc Pressure Fans "Selective Series"--Meet all pres sure requirements efficiently--made in various sizes from 8 in. to 10 ft. Bulletin SS-101 contains complete technical data on L-Type for low pressures and HL and H Types for high pressures. Giant Fans--Are made in 5 ft. to 10 ft. diameters and are directly connected to motor, chain or Tex-rope drive. Technical data concerning these fans is contained in Bulletin SS-101. Type H of lhs "Sdstiioe Striss.'' SO in., S hp. 11(0 r.p.m. 8100 c.f.m. against 1 in. sialic pressure Bifurcators--Can be placed in a straight duct without introducing right angle turns in the ducts or requiring extended shafts and bearings. As motor is located outside of air stream, safe, care-free operation is assured. Vari-Speed Fans--Speed selection is secured through variable pitch motor pulley. Quiet. Compact. Reliable. Bifurcalor, For special ventilating jobs tchert fumes of excessive temperature, corrosive or explosive character, are to be removed Duplex-Rotation Impeller Blowers--Consist of disc pressure fan wheels rotating in opposite senses so designed that the rotational losses are com pletely eliminated. The unit is directly driven by a DUPLEX-ROTATION motor, which eliminates belts and gears. It is equipped with ball bearings throughout and is suitable for horizontal or vertical mounting. This unit can replace any fan of same diameter now producing objectionable noise, without alterations. Impeller Blowers are also supplied with belt or gear drives. Write for Bulletin DR-101. 3-j5tage Duplex-Rotation Impeller Blower. Large air' volumes against high static pressures at low peripheral velocities. Extremely high efficiency over entire range of operation Giant Fan. Powers from 6 hp. to 100 hp. Volitates to 310,000. e.fjn. static pressures to 3 in. Fans Bayley Blower Company 1817 S. Sixty-Sixth Street Branches in Principal cities Milwaukee, Wis. Builders of Heating, Ventilating, Cooling, Purifying, Humidifying and Air Washing Equipment; Exhaust and Drying Apparatus, Mechanical Draft and Blast, Fans and Blowers of all Types Bayley Plexiform Fan: atomizer requires, very little attention, Is a multi-blade fan for supplying air for heating and ventilating systems, manufacturing processes, and will operate successfully under low water pressure. The orifices are large and this atomizer, unlike high pressure nozzles, cannot clog. drying systems, forced and induced draft sys tems. It is suitable for handling high or low temperature gases at medium or low pressure. Will deliver maximum quanti ties requiring minimum space with great economy. This is a distinct Bayley product, high class material and workmanship, properly designed to avoid excessive vibration and overstressing of parts. Inlets and outlets are properly sized for maximum delivery and maximum efficiency. Fans are fur nished in single or double width of any required arrangement and with sleeve or anti-friction bearings. Bayley Chinook Heating Sections: The Chinook sec tion is used with blast heating, venti lating and drying systems, and is suit able for high or low pressure steam cir culation. The base is divided into two chambers. Steam enters (see cut) the lower chamber, ris ing through 2irin. pipes located within the l^(-in. pipes leading from the upper chamber. Condensation takes place in Aeroplex Fan: the larger pipes, the water falling into the Is of high speed design with self limiting upper chamber and draining away through ' power characteristics. Application parallel the return outlet. The Chinook can be to the Plexiform Fan. Highly efficient and repaired in the middle of the bank without quiet in operation. Bayley Exhausters and Pressure Blowers: breaking steam connections or taking down a section. , Shipped assembled in smaller sizes, and Type MBM exhaust fan knocked down in the larger units. May is for heavy duty, hand be installed in horizontal or vertical ling refuse from industrial position. *y and textile plants. Type "SE" is used in handling Bayley'Chinookfin Heating Sections: smoke, fumes and dust Are the same design as the Chinook laden gases. Type "H" Heaters, using heavy gauge copper fin for high-pressure work. tubes. As compared with Chinook it is These units are highly efficient and of much lighter and occupies less space. . high class design and workmanship. Bayley Plexfin Unit Heaters: Bayley . Turbo Air Washers, Tftis unit in Humidifiers and De-Humidifiers: corporates The,Turbo Chinookfin Atomizer radiation and used in the 'Plexiform or Bayley Aeroplex fans. Washer pro The fan assem duces a bly including steady, fine top plate and spray. Water motor is re at low pres movable as a sure is deliv unit for main ered to the The Bayley Turbo Air Wother Show tenance and center, of a ing Turbo Atomizer and Eliminator inspection. The heating element is a re rapidly re movable unit. Casing all welded extra volving cone-shaped rotor provided with heavy gauge. . This is an exceptionally atomizing pins set in its periphery. This high grade unit at a moderate price. 900 Fans Buffalo Forge Company 484 Broadway, Buffalo, N. Y. Branch Offices ., _. ..T ................. A14 Standard Bldg. Knoxville--C. F. Sexton.TM------ ------------- _P. O. Box 2224 .724 First NatL Bk. Bldg. Los Angeles.708 Pershing Sq. Bldg. 5* N ............. Station Melrose, Mass. cSSotte-J- W-""fraser 4 Co., d,, CHiBLOTr p Q Bm 1436--124 Brevard Court Memphis--A. W. Shelby_____ __ ________ 134 S. Second St Minneapolis--E. F. Bell----------------------- 619 Foshay Tower Nashville--Southern Sales Co--------------117 Fifth Ave. N. New Orleans--A. C. Hayes1415 Carondelet Bldg. Chattanooga--H. T. Purcell Co------- - .502 Pound Bldg. New York Cm........................ ---------------- 39 Cortlandt SL Philadelphia..-_________________ ______ 703 Cunard Bldg. cSSTM::....................... ......... ......--418 Rockefeller Bide. Pittsburgh.......... ............,,........................... ...912 Fulton Bldg. San Francisco--Herberts-Moore Mchry. Co...550 Fifth St. Dallas--Buffalo Engineering Co., Inc._3!5 South Harwood St. Louis.______ ___ ________ :-....1596 Arcade Bldg. Denveb--Hendric 4 Bolthoff Mfg. 4 SuPPjr Co-1621-17th Street Diteoit--Coon-DeVisser Co-------2051 W. Lafayette Blvd. Greenville Geo. R. Morgan. ^ ^ ^ ^ Salt Lake City--Salt Lake Hardware Co. SeattleTM_________________ ____ ________2434 First Ave. S. Toledo--Carl M. Eyster Co---------------- 1922 Linwood Ave. Washington820 Woodward Bldg. Kansas Citt_.................................................315 Dwight Bldg. Kitchener, Ont_____Canadian Blower & Forge Co., Ltd. Wilkes-Barre--Power Engineering Corp., Coal Exchange Bldg. PRODUCTS: Heating and Ventilating Equipment, including: Unit Heaters, Multiblade Fans, Pipe Coil Heaters, Buffalo Air Washers, Buffalo Unit Air Washers, Buffalo Unit-Coolers, Drying Equipment, Mechanical Draft Fans, Air Preheaters, Exhaust Fans, Blowers, Dust Collectors, Disc Fans, Spray Nozzles. Buffalo Unit Coolers Sus pended Type: SC Cooler has , cop per coils suitable for cold water, brine, methyl chloride or Freon. Type SS units have steel coils, hot galvanized after as sembly, for use with ammonia. Compact, simple, inexpensive. Floor and Flat Suspended: Available for same kinds of refrigerants, but with capacities from 2130 to 6480 cfm. . Central Conditioning Cabinets: Type PC --for cool ing and heating. Heating coils are two-row copper fin type capable of heating from 70 F to 135 F with 2 lb steam. Cooling capacities-- from 3 to 24 tons. Buffalo Air Washers The outstanding features of Buffalo Air Washers are: eliminators in one piece and demountable; spray nozzles, non-clogging; suction screen extends entire width of tank; maximum contact between air and water spray. A complete line of selfcontained unit air washers is also available. Buffalo Unit Heaters Gas Units: Made in suspended and floor types. Total capacity 75,000 to 450,000 Btu in put per hour. All models equipped with full auto matic safety fea tures. Eliminates boiler room, fuel storage, and neces- Steam Unit sity for fireman or engineer; is easy to install; clean and automatically controlled. Write for bulletin. Steam Units: Both suspended and floor type units in a large range of capaci ties and with centrifugal or disk type fans. Buffalo "Limit-Load" Conoidal Fans with Silent Floating Bases The Buffalo "Limit-Load," high-efficien cy, non-over loading venti lating fan mounted on the silent, in sulated float ing fan base eliminates all motor and fan vibration, making an almost noiseless installation. Breezo Ventilating Fans Breezo fans provide efficient, inexpensive ventilation on any job where they may be used to exhaust into the open. Made in sizes from 8 in. to 36 in: diameter. 901 ^ Champion Blower & Forge Co. Manufacturers and Engineers Plant and General Offices: Lancaster, Pa. Manufacturers of Blowers, Ventilating Fans, and Exhaust Fans for Air and Material; and Blast Gates. Fans For Heating, Ventilating, Cooling, Drying or Forced Draft p Single Width, Single Inlet. Double Width, Double Inlet. Type "C" Manlvane Blast Wheels Built strong and substantial to withstand air resistance. Free from vibration and noise. Especially adapted for oil burner, stoker, general heating and ventilating purposes: where noise is objectionable. 902 Fans and Ventilating Equipment ILG Electric Ventilating Company Propeller Fans, Blowers, Unit Heaters, Air Conditioning Equipment 2880 North Crawford Avenue, Chicago, 111. Sales Representatives in all Principal Cities ILG SELF-COOLED MOTOR PROPELLER FANS The green Ilg Self-Cooled Motor Propeller Fan is used everywhere for removal of foul air, fumes, heat, etc. Features include: the patented Ilg selfcooled motor, dynamically bal anced, vibration-free, bucket type wheel, and a strong onenameplate responsibility. Motor, wheel and frame are all Ilg-built.- The ingenious self-cooled mo tor design of the Ilg fan com bines the low operating cost of the open motor with the pro tection of the fully enclosed motor. The black square tells the story. The fan action draws clean air through the vent pipe from the outside; circulates it through the motor (follow the arrows) and exhausts it. The Ilg motor stays clean, stays cool; no foul air can reach it. There is a complete range of Ilg fan sizes from 12 to .72 in. in A.C. and D.C. Each fan is thoroughly tested before shipment. Ratings are guaranteed to be in accor dance with the Standard Test Code of the A.S.H.V.E. and the National Association of Fan Manufacturers. The Motor that Breathe* OTHER ILG PRODUCTS Ilg Universal Multiblade Blowers--Ilg Type B Universal Blowers are designed to combine compactness, quietness and efficiency. Motor is recessed in side of blower, requiring no separate base. Multiblade wheel is mounted on motor shaft. There is no inlet bearing. Available also for belt drive. Capacities 1750 cfm to 70,000 cfm, single and double width. Ilg Type "B" Volume Blowers--The latest development in small volume, low pressure blowers. Light weight, quiet running. Dynamically balanced multiblade wheel is mounted on motor shaft. Motor and steel housing are supported by cast-iron base. Universal discharge. Available in.11 capacities, 180 cfm to 2100 cfm. Ilg Unit Heaters--Steam and Electric--Copper tube and fin construction and enclosed self-cooled motor. Ug-built throughout. For steam or hot water. Tested with 500 lb hydrostatic pressure. Available in 14 capacities; also, Ilg electric unit heaters for all electric operation, available in 20 sizes. Ilg Cooling and Air-Conditioning Units--Selfcontained Ilg Spot Koolers in ^ ton and 1 ton cooling capacities with water or air cooled compressors. Also central unit systems using floor cabinet or ceiling suspension units with remotely located compressor. For cooling, dehumidifying, and recirculating. Also, for heating and humidifying. 903 Fans and Blower Wheels The Torrington Mfg. Co. 50 Franklin Street, Torrington, Conn. PRODUCTS--All Aluminum Blower Wheels and Disc Propeller Type Fans SINGLE WIDTH SINGLE INLET BLOWER WHEELS Fans and Blower Wheels The Torrington Mfg. Co. 50 Franklin Street, Torrington, Conn. DOUBLE WIDTH DOUBLE INLET BLOWER WHEELS State rotation when viewing this end of Hub con be furnished for inside or outside of wheel. Actua Actual Nominal No. Blade Actual Blade Weight No. Size of Dia. O.D. Width With Hub Dia. Width Blades A B c D E F G H L Bore 0 M P T s w X)A 3 xi y. 27 3 iy. m IA A y. 1 2A A X B A 4 10-32 y. 3 oz. X) 3 xlH 27 3 iy. m 1A A X 1 2A A X B A 4 10-32 y. 3Koz. K 3KxlK 45 3H ZX If* lB A A A 2H A X Spu i-H Jb 10-32 y. iirsr 0 AVt^v. 34 m *A 2-h 2A ' A 1A 1 3K a K-K IA A 6 K-20 K 8Koz. 0A 4Kx2tf . 45 *A 4% 2-h 2A A IK 1 ZA H K-K IA A 6 K-20 l K 9 A oz. OB * I3 . 45 *A 414 2V, A lA 1 za 1! XrA IA A . 6 K-20 1 K 11A oz. KB 5 x2K 45 5 5H 2A 2y. A 1A 1 ZVs H K IK _i_ 6 K-20 1 A 13 oz. KA i> x2K 45 5 bH iy iy. A 1A 1 i'A H A IK A 6 K-20 1 A 13 oz. K b x3 38 5 i>A jy. 2H A IA 1 Z a H A 1A A 6 K-20 1 A 12 A oz. it) 6 x 1 31 6 HA IB 1. A IA IK 4B B K IA A 6 A-18 1 K 13 oz. 1A 6 x2 32 6 6k 2K IB A m 1A 4 H H K IA A 6 A-18 1 K 14 oz. IE 6 x2 45 6 6H iy. 1H A 1A IK 4H B A lA A 6 A-18 1 K 15 oz. 1 6 x3 31 BA 6H 3 y. 2B A Ik IK 4B H A IA A 6 A-18 1 K 15>$oz. 1C 6 x3 45 6 6H ZX 2B A IK IK 4B B A iA A 6 A-18 1 k 15K oz. ib 6 x 3 k 38 6. b 'A 3B. ZA A IK IK 4tt B A IA A 6 A-18 1 K 1# IKoz. 1KA 7Kx2 47 7 k l`A HA 2 A IA 1V, 5H A IA A 6 A-18 1 K 1#- 4Koz. 1KB 7^x3 37 TA 7K zy4 i'A A IA i x 5H H A IA A 6 A-18 1 K 1#- 4Koz- IK 7AxZA 47 'iy> `A 4 za A IA IX SH H A IA A 6 A-18 1 K 1#- 8Koz. iy.c 7Kx4M 36 !`A m 4X 4A A IA IX 5H H A IA A 6 A-18 1 M 1#- 9 oz. 9 x2 47 9 9A 2* IB A IK 2 m A A~A 2B A 8 A-18 2 K 2#- 1 oz. ini 9 x2K 48 9 9 A 2'4 2A A IK 2 JA A K-K 2 A 8 A-18 2 K 2#- 2 oz. THE 9 x 3 47 - 9 9 A iy. m A IK 2 lA A K-K 2 A 8 A-18 2 K 2#- 4 oz. 9 x3H 59 ik 9 x4A 47 9 HA 4 i'A A 1H 2 9 . 9 A 4k 4B A lK 2 m A K-K 2ft A 8 A-18 2 K 2#- 5 oz. 7K A K-K 2B A 8 A-18 2 K 2#- 8 oz. Hi 10Kx5K 47 10K lOtf 5B 5 A A 2 2K 8H A K-K 2H A 10 **-16 3 A 3#-12 oz. 2 12 x 6 .64 I1H 12A 6H &K A 2 2K 10 A B V,~1 3ft A 10 K-16 2 K 5#- 4 oz. *k 15 x.VJ4 64 1BA 18A m m A 2A 2K 12H H 1 4 A K 8 K-16 2 K 10#- 0 oz. 1. Attractive appearance. 2; Light weight minimizes power con-' sumption. 3. No protective finish necessary. 4. Lower transportation costs because of , . light, weight. , 5. Aluminum construction minimizes resonance and wheel operates more quietly. . 6. No rivet head or other projections on inlet face of wheel. 7. Patented construction reduces manu facturing cost. 8. Rugged design--tested to speeds far in excess of normal. . 9. Made from a special aluminum alloy having great strength. 10. Approximately one-third weight of steel wheels. 11. Low starting torque. 904 Actua Nominal No. Blade Actual Weight No. Size of Dia. O.D. With Dia. Width Slades A B C D E F G H J L Bore- T s Hub 00A 1 3 X 2K 27 3 3K l A 1W A X 1 2A 2A A K 10-32 1 4K oz. 00 3 X3 27 3 3K 1A IA A X 1 2A 3K A K 16-32 1 5K oz- A 0 ZA X 3 45 4Ax 4K 34 3K 3K 1H 1H A k 'A 2ti 3W A K 10-32 1 4K m 4rt 2A K IK 1 3K 4fi H H-K 1 7Koz. 14 oz. 0A 4Ax 4V4 45 4K 4K 2 2* K 1A 1 ZA 4H H K-K K-20 1 1# 0B 4Ax 6 45 4K 4K 3 2V, K l A 1 3K 6 H K-K K-20 1 1 ZA oz. KB 5 X 4K 45 HA 5 X 5K 45 5 5 5H 2K iy. K IK 1 5K 3A iy. K 1A 1 3K 5 ZA 6 n K K-20 1 1 # - 5 oz. K K Kt20 1 1 #- 6 . oz. A 5 X6 ID 6 X 2 38- 5 5>K 3A 2B K IA 1 3 A 6K H K K-20 1 l#-5, oz. 31 6 6K IK 1 A IK 1A 4H 2K H K A-18 1 1#- 5>*oz. IA IE 1 1C . IB fi6 X 4 X4 32 6 45 6 6 A 2A IB K IK IK 4H 4A H K A-18 1 1#- 8 -oz. 6B 2A IK K IA 4B 4A U K A-18 1 1#- TAoz. fi6 X 6 X6 31 BA 6K 3A 2B A IK 'K 4H BA K A-18 1 1#-12 oz. 45 6 6K 3A 2H A IK IK 4tt BA ti K A-18 1 l#-10Koz. 6 X 7K 38 6 6V* 3K 3A K IK IK 4H VK H K A-18 1 1 #--15 oz. 1KA TAX 4 47 7K 7K 2K 2 K IA W, 5 4K H K A-18 1 2#- 3 oz. 1KB IK 1KC 1KA 1J4D TAx 6 TAx 7K TAx 9 9 X4 9 X 5K 37 47 36 .47 48 TA 7K 3K m K IA IX BK H K A-18 1 2#- 4K oz. 7K 7K i'A 3K K IA W, 5H TX H k A-18 1 2 #-10 oz. 7K 7K 4 A 4A K IA ik BM 9K H K A-18 1 2#-HKoz. 9 9K ik IB K' IK 2 TA 4A A k-H A-18 t '3#-4 oz. 9 9K iy. 2K K IK 2 VH BK A K-K A-18 2 3#- 7.. oz. ' 1KB 9 X 6 47 9 9K 3K 2K K IK 2 VH 6^4 A K-K A~18 2 3#- 8K oz- 1HC 9 X 7y. 59 9 9K 3K 3A K IK 2 7K A K-K A-18 2 3 # -13 A OZ; IA 9 X 9 41 9. 9K 4B 4H A IK 2 TA 9A A K-K A-18 2 4 # -- 2 oz. IX 10Ax 1(>A 47 10 K ioh 3A BK A 2 2 12 x 12 64 11B 12A 6K 5H A 2 2K SB 10K A K-K K-16 2 5#-15Hoz2K 10K 12K B K-l K-16 2 8#-11 oz. 2A 15 X 15 64 15A 15A 7K 7K A 2K 2 12H 1BK H 1 K-16 2 16#- 8 oz. HOUSING SCROLLS. We do not manufacture housings but. have prepared drawing with tables of dimensions for Scrolls for each size wheel. Copy will be mailed upon request. . CAPACITY TABLES. Capacity rating and curve sheets showing static pressure, air deliveries and brake horsepower at various speeds are available for the majority of sizes and will be sent upon request. 90S Fans and Ventilating Equipment L. J. Wing Mfg. Co. Branch offices in 59 Seventh Avenue, New York, N. Y. Principal Cities Phone: CHelsea-3-0028 Factory: NEWARK, N. J. Wing Featherweight Unit Heaters and Process Heating Units; Utility Unit Heaters; Wing Scruples Safety Ventilating Fans, Fog Eliminators and Exhausters; Wing Forced Draft Blowers, Turbine or Motor-Driven; Steam Turbines; Man-Coolers; Wing Garage Heaters; Wing Door Heaters. Wing Featherweight Unit Heaters Light weight and vertical downward discharge of the heated air through high velocity multiple dis charge outlets are original and unique features of Wing Featherweight Unit Heaters. Thus down ward circulation of large volumes of warmed air to the floor and uniform distribution of it over the entire area is assured, with resultant economy in plant heating. Wing Featherweight Unit Healer--with the Wing They produce a pleasing sense of warmth at the floor level because the warmed air from each of the Featherfin Heating several heater discharges actually reaches the floor. Element There is a design of discharge outlet to meet every condition. Bulletin HS. DiStandard Kharat Outlets for Tyne HC Wing Featherfin Heating Element Extremely light in weight. By simple variations of the heating surface any desired final air tem perature may be obtained with any given steam pressure. Fin and tube extended surface type-- Hairpin or return bend design-- Detail of Wing Featherfin Headers of steel, tubular design-- Heating Element thawing Compression Union Tube Tested at 1000 lb. pressure. Connection Bulletin HS. Wing Utility Heaters A general purpose heater. Delivers heatair in one general direc tion. With adjustable vane diffusers and safety guard for fan. Bulletin VS. Wing Featherfin Process Heating Units, Wing Industrial Fog Eliminators Eliminate fog, odor and fumes in dye-houses, bleacheries. pasteurizing plants, chemical works, paper mills, etc. Easy to install. Bulletin FE-lt. . Wing Garage Heaters r Especially designed for heating garages. They are located above the open aisles, and deliver a high-velocity conical column of air downward in such a manner that it . rolls along the floor in I III I For manufacturing processes such as drying, aging, etc., requiring the recircu lation of the heated air. Motor or turbine every direction, put ting the heat on the floor and under the cars just where it is located outside air current. Bulletin P-2. needed^ Cuts yearly ' Wing Featherfin Heater Sections for cost of heating in half. T]nx G Heat,, M general blast heating. Bulletin HS-1. Bulletin G-l. Cone Discharge Outlet 906 - L, J. Wing Mfg. Co. Fans and Ventilating Equipment Wing Door Heaters A combined electric and steam directional heater, very compact in size and simple in construction. Suspended from ceiling over each opening. Used for instantaneously heating in rush of cold air at doorways of garages, bus terminal stations, freight houses, docks, piers, ship ping and receiving de partments. Bulletin D-l. Wing-Scruplex Safety Ventilating Fan A propeller type fan that delivers air against static pressure, quietly, efficiently and safely. The screw design propeller moves the air forward in straight lines__wi_th__o_u_t eddy_, _a_s_s_u_ri_n_g__h_ig_h__s_t_atic eiSmffiizcceii.ee^sinn7Acc1Syy0.. itno 60 in., capacities range from.950 I BFaECASMHINGC1IBSANFtOAIORO*lDAIKCOHNASNTDALIfETUDr DVO*mWT)I NOT COrii U* CONTACT WtTH BEARING.} to 52,000 c.f.m. Bulletin F-6. Wing-Scruplex Exhausters Fair! inlet Wing^eruplex Exhauster with bottom inlet Made for either horizontal or vertical opera tion--top, bottom or side intake. The motor is entirely outside the exhaust housing, therefore always easily accessible--kept clean and cool for any ventilating need where air must be drawn or forced through ducts. Bulletin ES. Wing Variable Temperature Featherfin . Heater Sections Obtainable separately for general heating and process work, or in combination with any of the Wing Unit Heaters. Will deliver air at any temperature from the maximum obtainable, with prevailing steam pressure, down to the temperature of entering air. The temperature of discharged air is controllable manually or automatically without throttling the steam supply--there fore proof against freeze-ups. Bulletin VT-1. Wing Motor-Driven Blowers for Forced Draft , The installation of Wing Motor-Driven Type EM Blowers and Combustion Controls on boilers of all sizes makes possible the use of Rice and Barley coal. Screenings and other inexpensive fuels with great savings in fuel cost, which usually pay for the blowers in- the first year of operation. Help maintain steam pressure and give increased capacity with minimum attendance. Bulletin MS6. ' Wine BM Burner Wing Turbine Blowers Forced draft for hand-fired or stoker-fired high pres-' sure boilers is economically supplied by the Wing Turbine Blower. Greatly increased boiler capacity, flexibility of control and thorough combustion of low cost fuels are obtained. These units occupy very, little floor space, and hence can be readily installed in any boiler room. Great savings can be effected in plant operation by the installation of Wing Turbine Blowers. Exhaust steam from turbine can be used for heating buildings or feed water or for processing purposes. Bulletin T-97. ` 907 Fans and Ventilating Equipment Albany, N. Y. Atlanta, Ga. Baltimore, Md. Boston, Mass. Buffalo, N. Y. Camden, N. J. Chicago, 111. Cincinnati, O. Cleveland, O. Detroit, Mich. Greensboro, N. C. Hartford, Conn. Indianapolis, Ind. Kansas City, Mo. Los Angeles, Cal. Milwaukee, Wis. Minneapolis, Minn. Montreal, P. Q. B. F. Sturtevant Co. Hyde Park, Boston, Mass. Slurleyanl PLANTS LOCATED IN Camden, N. J. . Hyde Park, Mass. Stubtevant, Wis. Galt, Ont. Framingham, Mass. Berkeley. Calif. Newark, N. J. New York, N. Y. Pittsburgh, Pa. Portland, Me. Portland, Ore. St. Louis, Mo. San Francisco, Cal Seattle, Wash. * Spokane, Wash. Syracuse, N. Y. Salt Lake City, U. Toronto. Ont. Washington. D. C. A. M. Lockett & Co. New Orleans, La. Houston, Texas Dallas, Texas The Cooling and Air Conditioning Corporation Atlanta Division of B. F. Sturtevant Company HYDE PARK BOSTON, MASS. Camden Chicago Los Angeles New York DATA ON HEATING, VENTILATING, AIR CONDITIONING AND VACUUM CLEANING EQUIPMENT FOR ARCHITECTS, ENGINEERS, CONTRACTORS The publications listed below have been prepared to aid the architect, engineer and contractor in the selection of proper equip ment for industrial, public, and private buildings of all types and sizes. If you do not have all of these publications in your file we will gladly send copies upon request. COOPERATION Sturtevant Engineers, located at each of the offices listed are always ready to co operate with architects, engineers and con tractors in the selection of equipment suitable for any prospective installation. VENTILATING FANS Catalogue No. 271-2 Multivane Fans . (Forwardly . curved blade type). . 381-2 Silentvane Fans (Backwardly . curved blade type). 414 Rewane Fans (Radial blade type). . 385 Propeller Fans. 332-1 Ventilating Sets (direct motor- driven centrifugal type fans for ventilating small rooms. Capaci ties: 80 to 1600 c.f.m.). 400-5-Direct - connected Fans and Blowers (Propeller Fans; Window Fans for kitchens and offices; Centrifugal Fans from 80 to 6460 c.f.m.; Portable Gas - Engine- Driven Fans; Coal Burning .' Blowers; Forge Blowers; Dust Blowers). .. Catalogue No. 345 Carbon Monoxide Asphyxiation arid Its Prevention. MISCELLANEOUS HEATING AND VENTILATING EQUIPMENT Catalogue No. , 377-1 Unit Ventilators.^ 395-1 Rexvane Speed Heaters (Floor type.unit heaters). 396-2 Speed Heaters (Suspended Type Unit Heaters). 382 Coal Burning Blowers. AIR CONDITIONING EQUIPMENT Catalogue No. ' 295-1 Air Washers. AC 101 Industrial Air Conditioning. 398 Comfort Air Conditioning. 389 Household Humidifiers. 378 Filticooler (Compact, high ef ficiency air washer. For filter ing, washing, humidifying, cool - ing, dehunudifying. Used prin cipally for public buildings and .N factories). 383 " Humidifilter (A humidifying . and filtering unit primarily adapted to central systems. Used for both comfort and industrial processing work). 384 Suspended Type Air Condition ing Units. 401-1 . Railway Air Conditioning. VACUUM CLEANERS Catalogue No. .. 397-1 Central System Vacuum' Cleaners. 413 "Vortex" Portable Vacuum . Cleaners. . . ... 908 Heaters, Unit E. K. Campbell Heating Co. 2441-3-5 Charlotte Street Factory Branch St. Louis, Mo. Kansas City, Mo. Sales Agents in Many Cities MANUFACTURERS OF HEATING, VENTILATING AND AIR CONDITIONING EQUIPMENT PRODUCTS E. K. Campbell Furnace Fan System of Heating and Cooling. Thermidaire Fans and Blowers. . Thermidaire Steam Unit Heaters. Thermidaire Blast Coils. ' Thermidaire Gas-Fired Unit Heaters, propeller and centrifugal fan type. Diffusers and grilles. The E. K. CAMPBELL FURNACE FAN SYSTEM is installed in more than a thousand buildings--churches, schools, theatres, auditoriums, factories, garages--in twenty-three states and Canada. The system is in use in 17 churches in Indianapolis; also in the Butler University Field House, reputed to be the largest building in the world heated by a furnace fan system--in forty-five churches and over a hundred buildings in greater Kansas City; twenty-eight churches, and other buildings in St. Louis including one printing plant completely air conditioned. This system is especially adaptable to buildings with large spaces that are intermit tently heated. Large volumes of air give low final temperature and even distribution, with low temperature gradient from floor to ceiling. Butler Field House, with 40,000 sq ft floor area in one room, has maximum temperature difference at any level of 3 F and a temperature gradient from floor to ceiling of 12 F in 85 ft. , An intermittently heated building has a large amount of cold material, which must be warmed before comfort is obtainable. The conservative ratings of the E. K. Campbell Furnace take into account this heating-up load, the furnace being able with hand-fired coal to put out double its rated capacity. ._' .With large air movement, ample furnace capacity, and a furnace which permits heavy firing with low stack temperatures, fuel economy naturally follows. In addition this plant gives ample humidity, ventilation without drafts or open windows, and summer cooling, either with air movement alone, or, in conjunction with other apparatus, positive cooling. " The firebox of the furnace is built of heavy flange steel, reinforced above the firebrick lining with an additional thickness of steel, giving greater strength and longer life. From the firebox the gases pass into an economizer, which utilizes the plunge draft and 'counterflow principles, the gases being taken out at the bottom. This increases heat extraction, makes the furnace economical to operate, arid the heavy construction makes it capable of standing the strain of heavy firing easily. Twenty-six years of pioneering experience in developing the system and manufacturing the equipment make our engineering service valuable. When our equipment is used as directed, we relieve the architect, engineer, contractor and owner of any expense needed under our guaranty of results. .' Thermidaire fans and blowers, for heating, ventilating, and cooling are sturdy, efficient and quiet operating. " _ Thermidaire steam unit heaters are built in all types. The heating element is all copper, with a special brazing which has equal mechanical strength to the copper, in suring permanent tightness. A wide range of types and capacities makes these units adaptable for any condition. .. .. Thermidaire blast coils have the same heating element construction as the unit heaters, all copper, hrazed for permanent tightness. Encased in heavy steel, they are easily installed, andymake a permanent installation. Thermidaire gas-fired unit heaters have the vertical tube, plunge draft design, with large gas passages, which make the units self-cleaning and maintain the high and con stant efficiency. ' '. E. K. Campbell Heating Co. also manufacture diffusers, and grilles of various designs. Neat, inconspicuous, finished in baked enamel with choice of several colors, they are suitable for most conditions. Further information gladly given on request. ________________________________ ____________ Heaters, Unit, Electric Heaters, Unit Electric Air Heater Company Division of The American Foundry Equipment Co. 677 Byrkit Street, Mishawaka, Indiana, U. S. A. Manufacturers of Industrial and Domestic Electric Air Heaters Industrial Electromode Heaters This type electric air heater design includes all the principles of steam unit heaters. The difference is that the source of heat supply is a set of wires instead of a Boiler House, piping and steam traps. Controlled by thermostats, electric air heaters are economical, easily installed and heat is available within one minute at any time, and cut off instantly when no longer required. Industrial Heater Model KW 8-3 3.0 !!-)'/: 11-6 4.5 6.0 14-10 14-15 10.0 15.0 20-25 20-35 25.0 35.0 27-45 27-60 45.0 60.0 32-90 90.0 32-120 120.0 Ratings BTU EDR 60 F Temp. Rise 45 F Temp. Rise Fan Diam. CFM FPM CFM FPM Price List 10245 42.7 155 515 207 690 b'/l 60.00 15367 64.0 233 382 310 5% 20490 85.0 310 508 412 660 9 90.00 34150 142.0 517 488 684 645 12 135.00 51225 213.0 776 232 1034 975 85375 356.0 1290 119525 498.0 1800 533 1720 712 16 240.00 750 2400 1060 153675 640.0 2325 204900 854.0 3100 570 3066 748 24' 330.00 760 4133 1000 307350 1280.0 4656 409600 1708.0 6208 727 6108 954 30 450.00 968 8280 (294 Portable Electromode Heaters This portable electric air heater meets the demand for portable heaters as well as for permanent installations. This type may be equipped with a built-in thermostat for.temperature control. A ' special switch can be added which. will permit running the fan without heat. A waterpan can be added so that 1 to 3 pints of water may be evaporated per hour to give humidity control. Portable Heater BUt-In Heater ModeL KW BTU EDR 60 F Temp. Rise CFM FPM 45 F Temp. Rise CFM FPM Face Area Sq Ft Diam. Fan Net Wt. Price List A-15 1.5 5122 21.3 A-20 2.0 6830 28.4 75 100 220 m 103 138 310 0.327 m 420 id /50.00 B-30 3.0 10245 42.7 t50 34C 207 .468 0.442 9 B-40 4.0 13660 56.9 200 450 276 625. 25 60.00 :.C-50` 5.0 17075 71.1 260 435 345 575 0.60 ip/. 32 70.00 C-60 6.0 20490 85.3 310 515 415 692 Prices f. o. b. Mishawaka, Ind. . For 25, 40, 50 cycle and D.C. current--add 10 per cent to list. 1-Kwhr = 3415 Btu = 14.23 sq ft Equiv. in Dir. Radiation. GO cycle A.C. is Standard-- other cycles and D.C. at extra cost for motor. Important: Specify Voltage and kind of current when ordering. . Bilt-In-Wall Type Electromodes This unit is designed to fit the heating requirements of the home, apartment, office or summer (winter) home. The grille is of an attractive design and may be finished with any color to harmonize with interior decoration scheme. This heater is installed on the standard spaced stud just above the baseboard and controlled by a thermostat it gives automatic controlled temperature in each or all rooms. Send for Data Book No. 236 910 Fedders Manufacturing Co. HEAT TRANSFER SPECIALISTS SINCE 1896 57 Tonawanda Street, Buffalo, N. Y., U. S. A. Manufacturers of Unit Heaters, Household and Commercial Electric Refrigeration Appliances and Air Conditioning Equipment FEDDERS SERIES 3 UNIT HEATERS Handsome external appearance is an indication of advanced engineering design inside as well as outside. Sturdy Series 3 Unit Heater Cabinets reinforced with integral channel members pro tect the heating element from torsional stresses and twist due to piping strains. Full Floating Mountings allow for expansion and maintain element alignment in cabinet. Copper tubes having a 1 to 3 streamline ratio and patented individual convoluted fin design eli minate differential expansion stresses between neighboring tubes. Curved headers provide extreme strength and eliminate diaphragmatic action thus assuring a stable heating element. This combination of handsome appearance, rugged construction and quiet operation makes them ideal for commercial as well as industrial applications. Twenty standard models in well graduated capacities up to 1300 sq. ft. EDR. Write for Catalog. Pat. 1,970,105; other Pata. Pending FEDDERS STANDARD AIR CONDITIONING SURFACE Fedders complete line of Air Conditioning Surface, built in capacities up to 100 tons I.M.E., is cataloged and rated on a package basis. It simplifies engineering of the job. All copper and brass construction for high heat transfer efficiency. Fedders manifolding provides proper distribution throughout the surface and reduces internal friction to a minimum. Approved by Under writers' Laboratories. Fedders High Capacity Ther mostatic Expansion Valves are easily adjusted and provide sensitive, accurate refrigerant control. Write for catalog giving complete specifications and capacities. (Pat. pending). , MODEL 33, HIGH CAPACITY THERMOSTATIC EXPANSION VALVE Fedders Model 33-HC Valves help get the greatest effectiveness out of the coils. On multiple section coils, the settings of the valves con trolling each section can be easily adjusted in accordance with the varying temperature differentials as the warm inlet air becomes cooler as it progresses through each section of the coil. Orifice: 0.218 in. Diameter. Capacity: 4 tons with Freon. 8M tons with Methyl Chloride. 911 V ' - Heaters, Unit Modine Manufacturing Co. 17th and Holburn Streets, Racine, Wisconsin Branches in All Principal Cities MODINE UNIT HEATERS Application--Not only successfully used for industrial, garage and similar space-heating applications, but ideally suited also to show-rooms, stores, oil stations, churches, school rooms, resi- Center opening is patented provision for direct suspension from Steam Supply Branch Upper Header is a copper pipe Tabes brazed Into hdeegardeeersaFt 1350 Red-brass tubes round for strength Resist corrosion even better than copper At this point Velocity Generator straightens oat * air stream from fan Copper Fins Fins metallically bonded to tubes Lower Header is a copper pipe Bronze Outlet Casting structurally but assure far more effective, economical distribution of heat: (1) The Expansion Bend given each tube of the condenser before entering lower header, provides for free expansion, thus eliminat ing expansion strain from being transferred to header tanks. (2) Velocity Generator for redirecting and controlling the heated air stream, assures greater possible throw consistent with comfortable heating. (3) Direct Pipe Suspension greatly facili tates horizontal redirection of the heated air stream, permitting full 360 deg rotatability. Also means far easier instal lation, at less cost--no brackets, pipe rods or straps being necessary. Write for Unit Heater Catalog 635. . MODINE COPPER CONVECTORS A convector comparatively light yet unusually sturdy in construction. Avail able in a wide range of sizes and four general types--Concealed, Recessed, Floor Cabinet and Wall Cabinet. For steam, vapor or vacuum systems; line also in cludes a hot water type copper radiator designed specifically for hot water systems. Write for Catalog 135. . Bach tube of condenser, before entering lower header, beads in a way which provides for* free expansion. dential recreation rooms, etc. They have also effected important economies in the drying of paint, leather, enamels, paper, wood, etc., by speeding up and bettering the drying process. Description--Exclusive features that not only make the Modine a better unit MODINE UNIT HEATERS MODINE COPPER-CAST RADIATORS A combination of copper and cast-iron, that combines converted and radiated heat for greatest comfort and economy' Modine Copper-Cast heats faster than cast-iron because of the copper convection unit, and cools much slower than unas sisted convectors, thus maintaining a more even temperature than either. Write for Catalog 135. CAPACITIES AND DIMENSIONS (In Inches) Model No. Over all Height Width Depth Less Motor E.D.R. C.F.ld.. Motor R.P.M. 76 126 152 181 204 238 275 352 440 542 710 903 1163 1545 2015 jO'/z 16. 18 18 18 18 w2 22Y2 22V? 23 i2/6'AVi m, 3036 9% 13 15 15 15 15 18 18 18 22 22 26 26 SB. 5% 6 8 8 8 8 9 9 9 9 9 10A 10% 11 II 76 126 152 181 204 238 275 352 440 542 710 903 1163 1545 2015 187^ 456 540 770 735 731 1052 1425 1320 1710 2230 3000 4050 5400 6540 1550 1590 1590 1140 1140 1140 1140 1140 1140 1125 1120 H25 mo 1125 1110 All above models are available with variable speed motors: Unite for hot water application also available. MODINE HUMIDITIONER TheNHumiditianer, a low cost domestic air conditioner used in conjunction with a radiator heating system. It humidifies, . cleans, circulates heated air; can . be furnished -with cooling coil for living quarter cooling. The Humiditioner is ordinarily installed in the basement, suspended from the ceiling where it takes up no floor space; gives benefits of air conditioning without sacrificing virtues of _ radiator heating. '. Write for Catalog 135. ' OTHER MODINE PRODUCTS Modine also offers complete lines of Blast Heaters, Cooling Coils and Unit Coolers. Data gladly furnished on request. . 912 Healers, Unit The Unit Heater and Cooler Co. Wausau, Wisconsin Offices in Principal Cities MANUFACTURERS OF THE GRID UNIT GRID UNIT HEATER DATA . Delivers More Warm Air to Floor and Working Zone `Varies with type of motor. Model No. Dimensions A B C D` Face Area Sq. Ft. Motor Volume at Hp. R.P.M. Fan Capacities 5 Lb. Press. 60 Air B.T.U. Final Temp. Approx. '--..Pipe Sizes Shipping Weight Supply Outlet 1015 11% 15% 9 1020 11% 20% 9 141/2 14% .52 .69 1200 15 12% n 14 171/2 1.04 1500 22 18 l l'/i 20 1.67 1520 27 18 ll'/z 20 . 2.2 2000 27 23'/. ll'/z 211/2 2.8 2025 32 23'/, H'/2 211/2 3.6 2500 32 28% ll'/z 28 4.5 2530 36 28'/2 ll'/z 28 5.3 3000 38 33 13% 29 6.5 1/30 1/30 1/20 1/30 1/10 1/20 1/8 1/20 1/6 . 1/10 1/6 1/10 1/2 1/4. 1/2 1/4 1 1/2 1/2 1600 1500 1700 1150 1750 1150 1750 1150 (150 850 1150 850 1150 850 1150 850 1150 850 220 285 711 515 1450 1015 1700 1288 2500 1835 2875 2380 4200 3375 4650 3350 8100 6350 19450 24200 46000 . 34900 77500 65500 104000 83500 148000 . 113000 177000 158500 225000 197000 282000 226000 394000 341000 119 122 (09 118 113 118 114 117 - 115 120 108 113 115 121 104 109 90 %* 100 % 120 ,, PA* 210 w 250 I'/z' 320 2* 370 2" 440 2* 500 V 725 2/2' %' .%' 1%" 11/4' w IV/ 1'// p// p// w Grid Unit Heaters--Reduce fuel cost and maintenance expense--no damage possible to Grid due to electrolytic action as it cannot take place in Grid Units. Long Life--Efficient Service--Good for 250 lb. working pressure. Manifolds or Headers and Steam Chamber--Cast High Test Iron. Fin Surface--Aluminum alloy cast metal to metal bond with steam chamber. Lower outlet temperatures and greater volume delivers warm air to working zone of room, thus eliminating heat losses at ceiling and avoiding stratification. 913 Heaters, Unit YtUING RADIATOR Kjcrtnpjxruj- Racine, Wis. Representatives in All Principal Cities Manufacturers of Young Unit Heaters--Convection Heaters--Blast Units--Unit Coolers--Evaporators--Commercial Heat Transfer Units Model "SH" Unit Healer Commercial Heal Transfer. Unit The Young line of heating and cooling equipment is complete. Thus the architect, heating con tractor or engineer may select Young products to meet his most exacting specifications. There are 24 different models of Suspended Unit Heaters equip ped with constant or variable speed motors. Floor Type Unit Heaters have capacities from 120,000 to 800,000 Btu per hour. Young Blast Units and Com mercial Heat Transfer Sur faces may be used for various applications operating in con junction with heating, cooling, or air conditioning systems. Young Unit Coolers are used with cold water, brine, or any. common refrigerant. Young Evaporators for use with Freon or Methyl chloride are scientifically designed to distribute the liquid with one or a group of expansion valves. There are four distinct types of Convection Heaters--free stand ing cabinets, recess cabinets, wall hung cabinets, and plastered-in enclosures. All models incorporate the Streamalre design with large elliptical tubes which make Young convectors the outstanding in stallation for use with one-pipe or two-pipe steam, vapor, vacuum, or hot water heating systems. 914 Evaporator Heating and Cooling Surface (Fan System) Aerofin Corporation 850 Erelinghuyeen Avenue Newark, N.J. Manufacturers of Aerofin The Standardized Light-Weight Encased Fan System Heating and Cooling Surface 11 West 42nd Street, NEW YORK Land Title Building United' Artists Building Burnham Building PHILADELPHIA $ DETROIT CHICAGO 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 encased Units, ready for pipe and duct connections. The patented casings are built of pressed steel and are exceptionally strong and rigid, protecting the Unit from all the strains of pipe connections and expansion or con traction in service. The casings are flanged on both faces, top and bottom, and template punched for bolting together adjacent Units, or for duct connection. Fig. 1 Flexitube AEROFIN Flexitube Aerofin: (Fig. 1) supplants the original non-corrodible Low Pressure Aerofin. - Flexitube Aerofin is distinguished from all other developments by its off-set tubes. This flexible single-pass) header-to- header design so perfectly relieves or absorbs expansion and contraction strains that header and header-joint construction adequate for high pressure service may be employed, and the permanency of the contraction assured thruout the practically unlimited life of the surface. Single-pass tube construction is essen tial for low pressure service and is desirable for intermediate pressures (up to 200 lb.). The headers are one-piece bronze cast ings, machined for tube joints and pipe tappings. The joints between the copper tubes and the headers are of a patented type made by using a brazing material applied at high temperature and have proved stronger than the tube itself under all operating conditions for which Aerofin is sold. We believe this joint to be the most practical and dependable yet developed. . The arrangement of Supply and Return connections readily lends itself to every installation requirement and permits in stallation in any position, tubes vertical or horizontal, or Units "laid flat" for vertical air flow. Uniform steam or cold water distribu tion thru every tube is assured by proper orifice restriction at supply ends of tubes. Design and Construction: The heat- transfer surface in Aerofin is a plurality of seamless copper tubes about which is wound a helix of copper ribbon, approxi mately smooth. 7 The extended fin surface is applied and tinned while held in position, by highly developed automatic machines. The tin ning of the tube and the extended surface makes them metallicly integral, affording maximum heat transmission and per manent effectiveness. 915 s Aerofin Corporation Healing and Cooling Surface (Fan System) Six sizes 150 to 1624 c.f.m., 200 lb. work ing steam pressure. . Fig. t Flexitube Aerofin can also be made all aluminum--or admiralty tubes can be furnished. Flexitube Aerofin is constructed as briefly described above. In Universal Aerofin and High Pressure Aerofin the seamless tubes, with their extended fin sur face, are continuous. (See Figs. 2 and 3.) Standard Casings: The casings of all Aerofin Units are 29 in. wide (except 6-tube Universal Aerofin which is 21^6 in.) across tubes, and 12 tubes wide Flexi tube which is 20 in. across tubes, from outer edge one flange to outer edge opposite flange, and 10 in. deep in direction of air flow. Length of casing is nominal tube length plus 8H in. Fig. 4 Aerofin Continuous Tube Water Coils: Are designed for air cooling by circulating cold water through the Aero fin and air over the extended fin surface. These units can be made for either hori zontal or vertical air flow. Tubes and fins are made of copper, com pletely tinned with a permanent metallic bond between fin and tubes. Headers are made of one-piece cast bronze, and casings of heavy galvanized iron. Every unit is tested to 10001b. hydro static pressure. For details see Aerofin Continuous Tube Water Bulletin. Fig. S Aerofin Sizes: FLEXITUBE AERO FIN: Made in thirteen standard tube lengths, and in 2 widths, either one or two staggered rows of tubes per Unit, in 5 series (as explained in Bulletin). Universal Aerofin: (Fig. 2). Available in one-row or two-row Units, 6-tubes or 9-tubes across face, in seventeen standard tube lengths, between 2 and 10 ft., inclusive. . High Pressure Aerofin: (Fig. 3). Made in thirteen standard tube lengths 2 ft.; to 8 ft., either one, two or three staggered rows of tubes per Unit. Aerofin Encased Booster Units: (Fig. 4.) For horizontal or vertical air flow. Fig. 5 - Six (6) Row Continuous Tube Water Coil with front end cover removed, shooing supply and return header with connections for air vents. This is a left-hand unit (supply header on left side) for air flow from right to left. 916 Aerofin Corporation Heating and Cooling Surface (Fan System) Narrow Width Aerofin: (Fig. 6), is to be used, for Cooling only. Depth of casing is 5 in. instead of 10 in. This saves half the space required, in direction of air flow. Straight tubes. Made in one or two rows deep only. reducing fittings, or adaptors to com pression fittings. The design of Aerofin (Direct Expan sion) allows a wide selection of inde pendent circuit arrangements for the use of one or more compressors of the same or of different capacities operating entirely independent of each other. Fig. 6 - Aerofin Direct Expansion Cooling Units . . Aerofin Direct Expansion Cooling Units constitute a new development in Surface Cooling. (See Fig. 7.) Available for use with Freon or Methyl Chloride, , these units are designed for the maximum cooling effect in a given space. The novel and unusual design provides for a maxi mum of operating efficiency by supplying refrigerant for each row of tubes from a header to several passes in the face of the unit, thus maintaining full cooling effect with wet gas throughout all the tubing, except for a necessary slight length at-the end of each pass to provide a. sufficient degree of superheat to insure dry gas entering the suction header. Each Row is entirely' separate. Units e . are built with either one, two or three . rows of tubes and by bolting two units face " to face, .4 rows, 5 rows or 6 rows may be . had two units in depth. , Units are made in eleven lengths and *" Jtwo widths, which with 1 row, 2 rows, 3 rows, 4 rows, 5 rows and 6 rows deep, . makes available 110 combinations. , Then several units may be installed in ' height and two units in width (since supply and return headers are on same end of each unit), so that all varieties of. installation may be furnished. Units are designed so that each row oftubes may be controlled separately. All headers are equipped with standard Mueller fittings, which may be reduced to size desired by using standard sweated Fig. 7 . End plate removed showing distributing and suction headers Steel Supporting.Legs: Standard steel supporting legs, 18 or 24 in. high, template punched to same bolt hole centers as standard casing, are furnished when ordered. These legs may be attached quickly and obviate necessity of any other foundation. Advantages: Aerofin weighs but 9 to 16 per cent as much as equivalent castiron and occupies about H of the space. Expensive foundations are unnecessary, building re-enforcement is not required and the Units may readily be suspended from beams or roof trusses, or installed snugly in any out-of-the-way corner. Sale: Aerofin is sold only by manu facturers of nationally advertised ,, Fan System Apparatus. List upon request. Ask Newark for Heating Bulletin G32 at once, or Direct Expansion Bulletin D-JE 34 or for Bulletin, C. T. 35, Water Coils. 917 Heat Surface The G & O Manufacturing Company 138 Winchester Avenue ' New Haven, Connecticut INDIVIDUAL FIN TUBING RADIATING ELEMENTS FOR UNIT HEATERS (High AND Low Pressure) AND CONVECTION HEATERS nmum TOfnnmi INDIVIDUAL G & O FINS--The use of in dividual fins results in high efficiency in heat transfer from primary tube surface to secondary fin surface, because all G & O fins have ample collars around the tube opening insuring liberal contact with tubing. ANY SIZE OR .SHAPE^-Fins of any size or shape may be obtained giving any desired pro portion of primary and secondary radiating surface. .' SQUARE FINS--A squareTin has about 30% greater surface than a round fin of a ' diameter equal to a side of the square. . ' INDIVIDUAL FINS--Individual fins permit of any fin spacing: also, of using fins in groups at intervals along tubes! Fins placed at practically any angle on tubes. VARIOUS SHAPES--G & O individual fin tubing is furnished in straight lengths: in U bends with short i*adii: in continuous return bend coils, or other shapes. Ends of tubes may be left free of alloy for mechanical joints. G & O Individual Fin Tube Data O.D. of Tube Standard Sizes Fin Size \ Pm Surface Spacing per per Linear Inch Foot vs vs. vs vs vs r VSI. Wq. VS Si. ll/r'r'd. 1 VS *q. I'/S q. 6 0.59 sq. ft. 6 . 0.81 sq. ft. 6 0.64 sq. ft. 6 1.61 sq. ft. 6 - 2.50 sq. ft. 6 4.00 sq. ft. 918 Heating and Piping Systems, Industrial GRINNELL COMPANY. Heating, Industrial and Power Plant Piping, Fittings, Hangers, Valves, Pipe Bending, Welding, Piping Supplies, Etc. Executive Offices: Providence, R. I. Offices, Plants and Branches Albany, N. Y. Atlanta, Ga. (Plant and Foundry) Aububn. R. I. (Plant and Foundry) Baltdaobb, Md. . Boston, Mass. Bottalo, N. Y. Cbablottb, N. C. (Branch) Chicago, III. (Branch) Cincinnati, Ohio Cleveland, Ohio (Branch) Columbia, Penna. (Plant) Dallas, Texas Dvtboit, Mich. Kbabnt, N. J. (Branch) Milwaukee, Wik Minneapolis, Minn. (Blanch) Newahe, N. j. Net Obleans, La. Net Yoax, N. Y. Philadelphia, Penna. (Branch) PCTTSBOBOH, PENNA. ' PnorinENCB, R. I. (Plant and Foundry) Rochesteb, N. Y. St. Louis, Mo. (Branch) St. Paul, Minn. (Branch) ' Warhbn. Ohio (Plant nod Foundry) Los Angeles, Cal. (Branch) GRINNELL COMPANY OF THE PACIFIC Oaxland, Cal. (Branch) San Francisco, Cal. (Branch) Seattle, Wash. (Branch) Montreal, Que. (Branch) GRINNELL COMPANY OF CANADA, LTD. Vancouver, B. C. (Branch) Toronto, Ont. (Plant and Foundry) Oshawa. Ont. (Foundry) Winnipeg, Man. ' PRODUCTS AND SERVICES-- Complete Service on materials to Specification on Power Plant Piping, Industrial Piping, and Industrial Heating Systems; Prefabricated Pip ing including Pipe Cutting and Threading, Pipe Bends, Welded Headers, Welded and Welding Fit tings, Lap Joints and the Grinnell Mine of products for Super Power. Grinnell Equiflo Valves for forced hot water heating systems; Grinnell Adjustable Pipe Hangers and Sup ports; Grinnell Cast Iron and Mal leable Iron Pipe Fittings; Grinnell Malleable Iron Unions; Grinnell Weld ing Fittings; Grinnell Thermoliers (Unit Heaters); Grinnell Thermofin (Convectors); Grinnell Unit Coolers (for refrigerating service); Thermoflex Traps and Heating Specialties. Also Humidifying Systems; Con stant Level Size Circulating Systems; Piping for acids and other special materials.. Malleable Iron, Brass, Bronze and other Castings; Brass, Cast Iron, Wrought Iron and Steel Pipe; Seam less Steel Tubing in Iron Pipe Sizes. Valves: Check, Globe, Pressure Re ducing and Regulating, Quick Open ing, Safety and Y. ' Automatic Sprinkler Systems; Stand ' Pipes; Underground Supply Mains; Hydrants; Fire Pumps; Pressure and Gravity Tanks. Grinnell "Junior" Automatic Sprinkler Systems for Basements and other hazardous areas of Dwellings, SmaiS. Apartment Buildings, Schools, Churches,-Stores, etc. . Grinnell Equiflo Valves For Forced Hot Water Heating Equiflo Valve The designing of forced circulation hot water heating systems is so simplified by the Grinnell Equiflo Valve that they can be laid out and installed as easily as vapor or steam systems. This valve consists of a regular type packless radiator valve with a cartridge or tube made up of a series of orifices and baffles capable of setting up any required frictional resistance.. This method of establishing any desired resis tance does away with elaborate calcu lation of pipe sizes. Grinnell guarantees perfectly balanced circulation to_ each and every radiator where these valves are installed throughout the system. Equiflo Data Book sent to interested parties. . For Data on Thermoflex Traps and Heating Specialties, see page 1015 Grinnell Company, Inc. Heating and Piping Systems, Industrial Thermouer Patented THE GRINNELL UNIT HEATER Industrial and Factory Types--125 Lbs. W.S.P. Thermolier is a ruggedly built unit heater whose efficiency and dependability have been proved by actual performance in field service. Thousands of them are installed in industrial buildings and commercial structures of all types of occupancy. Thermolier has 14 points of superiority, the most outstanding of which is the internal cooling leg built right into the unit, an exclusive Ther molier feature. See drawing below. Radiation is from brass-finned seamless copper U-tubes rolled into a cast-iron tube sheet. No solder is used for strengthening joints and there are no flat horizontal surfaces to catch dirt. Units may be controlled manually or automatically, singly or in groups. Installation and piping are extremely simple and inexpensive, hence the unit may be moved from one location to another at small cost if found desirable on account of changes in building or occupancy. The complete line includes 22 Models in Two Types. . Thermoliers provide maximum distribution of heat without objectionable drafts. Specifications Fan--Grinnell special of rugged construction. Motor--heavy duty, oversize, enclosed, moisture-proof. Housing--Copper on Industrial Type with rubbed lacquer, finish; steel on Factory Type finished in gray duco. Frame--Heavy pressed steel, providing rugged support for motor and fan. Special Features--Adjustable swivel hanger rod couplings; louvers rigid, but easily adjustable: integral cooling leg insuring perfect drainage through one thermostatic trap for pressures up to 25 lb. , For pressures not exceeding 125 lb., a thermostatic trap of proper construction can be used and should be attached directly to the unit. ' CAPACITIES 60 F. Entering Air Temperature--2 lbs. Steam Pressure Model Nos. 20 . 20L 50 30L 40 40L 50 50L B.t.u. . per Hoar 22700 17700 31700 23,200 69,400 53.300 90.700 67.100 Model Nos. 60 60L 70 70L 80 80L 90 90L B.t-u. . Model per Hour . Nos. 104.800 77,700 117.000 100.000 164.600 139,300 189700 151,600 . 100 I00L 140 140L 180 . 180L B.t.ta per Hour 234.000 196.000 320,000 271.000 368.000 294,000 Data Book* cover ing other pressures and temperatures, dimensions and complete installa tion- information on application. Address Grinnell Company, Inc., 277 West Exchange Street, Providence, R. I. 920 Grinnell Company, Inc. Heating and Piping Systems, Industrial GRINNELL ADJUSTABLE PIPE HANGERS AND SUPPORTS One of the chief advantages of Grinnell Adjustable Hangers is that they permit adjustment of pipe lines after installation, thus obviating the necessity of tumbuckles or the removal of hangers. Their time and trouble-saving qualities during installation are equally exceptional. Below are shown a few Grinnell Hangers and Supports of par ticular interest to heating engineers. Send for Hanger Catalogue showing complete line. Pit. No. 101 Solid Ring Adjustable Swivel Rings (Patented) These Malleable Iron Adjustable Swivel Rings can be used with Coach Screw Rod or Machine Threaded Rod in connection with practically any type of Ceiling Flange, Expansion Case, Insert, etc. Adjustment of at least 1)4 in. is secured by turning Swivel Shank. Swivel Shank automatically locks, preventing loosening due to vibration in the pipe line. The Split Ring permits adjustment either before or after Ring is closed. A wedge type pin is loosely but inseparably cast into the hinged section for fastening this section after pipe is in place. Fig. No. 104 Split Ring Fig. No. 174 Swivel Pipe RoU Adjustable Swivel Pipe Rolls (Patented) An adjustable type of pipe roll using a single hanger rod. Swivel Shank allows vertical adjustment and automatically locks, preventing loosening from vibration. Universal Concrete Inserts (Patented) Made of air furnace malleable iron, in onfi body size, to take a special removable nut, tapped for % in., in., % in. or % in. rod as required. Nuts automatically lock by means of V-type teeth on both insert and nuts. Fit. No. Universal Insert GRINNELL WELDING FITTINGS N 50 Elbow, Long Turn Grinnell Welding Fittings are made from Seamless Steel Pipe and possess the same physical characteristics as standard, extra strong and o.d. steel pipe or seamless steel pipe of comparable size. They can be used under the same conditions, pressures and temperatures as the pipe itself. Welding faces for all plain circum ferential Butt Welds are scarfed or beveled to the regulation 45 deg. angle with 6 in. square end on inside of fitting. Angles of bevel other than 45 deg. can be furnished on special orders. Wddint Outlet Weldint Tee 3 Lap Planted Wddint Neck 921 Threaded Outlet y Heating and Ventilating Units John J. Nesbitt, Inc. AND Buckeye Blower Company Manufacturers of Heating, Ventilating and Air Conditioning Equipment EXECUTIVE OFFICES FACTORIES State Road and Rhawn Street Holmesburg, Philadelphia, Pa. Holmesburg, Philadelphia, Pa. Columbus, Ohio Buckeye Sales and Service Offices in Principal Cities of U. S. A. Sales and Service on Nesbitt School Room Unit Ventilators through Offices of American Blower Corp. Below -- Cross - section view showing the Nesbitt Syncre- tizer mixing outdoor and room air Called Tomorrow's Heating and Ventilating Unit Today, because of its easy adjustment to present or future ventilation requirements. Made in three types or cycles of , control--F, A, and O. All three types recirculate all room air during the heating-up period, before room occupancy. Type F, during room occupancy, introduces all outdoor air. Type A, during room occupancy, introduces any desired minimum quantity of outdoor air when heating is required, and an increasing quantity, up to all outdoor air, when cooling is required. Type F may be readily converted to Type A cycle of control at any time by a simple adjustment within the unit. ' Type O, during room occupancy, introduces a variable quantity of outdoor air without a fixed minimum. The quantity supplied is governed by the indoor and outdoor tem-v peratures, and is that volume required to maintain a minimum air-stream temperature-- usually 60 deg--at the fan discharge, before the air passes through the unit radiator. . All three types are made in the same size and style of casing for a given capacity, and all have the same arrangement of component parts. The differences are in the cycles of control. All three have the Nesbitt Airstream Minimum Temperature Control to prevent . cold drafts. Ask for Publication 225 (engineering data), and Publication 226 (The Story of Syncretized Air). . Nesbitt Series B Thermovent--for Large Interiors A large-volume unit ventilator incorporating three distinct features which have been proved essential to the proper heating and ventilating of auditoriums, gymnasiums, assembly halls, anti like gathering places: (1) Quietness of operation, due, in part, to large-diameter, forward-curved fans operated at low speeds, with V-belt drives; (2) . Modulated Steam Valve Control, with, uniform discharge temperatures over the entire radiator assured by Nesbitt internal steam-distributing tubes; and (3) Air-Stream Minimum Temperature Control, the Nesbitt development which prevents cold drafts. Furnished, like the Nesbitt Series 400 Syncretizer, in three types or cycles of control-- F, A, and O--to deliver all outdoor air, or to partially recirculate, with or without a fixed minimum quantity of outdoor air. Available in capacities ranging from 2000 to 6000 cfm, and in two types of casing, for exposed or hidden location. Ask for Pub lication 227. 922 John J. Nesbitt, /nc. & Buckeye Blower Co., Heating and Ventilating Units Buckeye Giant Unit Heater A blower, draw-through type unit heater for the economical heating of large areas in industrial plants, garages, airplane hangars, etc. Made in a variety of capacities, ranging from 1880 cfm, 139,500 Btu, to 19,600 cfm, 1,290,000 Btu, with 2 lb steam, 60 deg entering air. Giant Heaters are equipped with Nesbitt Copper Finned Tube Radiating Surface for operating steam pressures up to 150 lb gage. Also applicable for use on Forced Circulation Hot Water Systems. Giant Heaters are built for Floor Mounting--Wall Mounting (both Standard Vertical and Inverted Vertical) and Horizontal Suspended. Wall boxes and outside air dampers can be furnished with all types. Giant Heaters are furnished with or without the Thermadjust Damper. This efficient bypass damper with automatic or hand control prevents overheating and stratification and effects substantial fuel savings by controlling heat output in definite relation to demand. Giant Heaters may be had with either V-belt drive or direct-connected motor. Ask for Buckeye Publication 145. Giant Unit Heaters are tested and rated in accordance with the Standard Test Code of the American Society of Heating and Ventilating Engineers and the Industrial Unit Heater Association. Buckeye Unit Heater A rugged, compact, suspended type, disc fan unit heater, built in capacities ranging from 810 cfm, 35,800 Btu, to 5030 cfm,' 313,500 Btu, with 2 lb steam,' 60 deg entering air, and for oper ating steam pressures up to 150 lb.' Also adaptable for' use on Forced Circulation Hot Water Systems. Available in either single- or multi-speed. Buckeye Unit Heaters may be conveniently located to supply heat exactly where it is needed, and the louvers are individually adjustable to direct the air flow to the proper level. Heavy brackets are provided at the top of each heater for attachment to hanger rods. ' Recirculating ducts or fresh air intake ducts, together with the necessary wall boxes and louvers, will be furnished with these heaters when specified. The propeller fans used have been specially developed for these heaters and they combine lightness and durability with exceptionally high aerodynamic efficiency. They are perfectly balanced and are securely attached to the motor shaft. Ask for Buckeye Publication 144. Buckeye Unit Healers are tested and rated in accordance with the Standard Test Code of the American Society of Heating and Ventilating Engineers and the Industrial i Unit Heater Association. Nesbitt Heating Surface with Steam-Distributing Tubes The increasing application of automatic temperature control to heating, ventilating and air conditioning systems has created the need for this new type of blast steam heating surface. Nesbitt Copper Heating Surface, through the ,use of all-copper, fin-andtube construction, retains the rapid steam condensing capacity and the permanence proved for light-weight copper radiation, and gains unique controllability by inserting, within the usual steam tubes, additional or steam-distributing tubes. These carry the steam equally to all parts of the radiator section, regardless of the quantity supplied. Thus, whether the section is.operating at full capacity or merely tempering the incoming air, a uniform discharge temperature is assured. Possibility of freezing is eliminated under normal operating conditions. Nesbitt Copper Heating Surface is made in a wide range of capacities, to meet all conditions. Fins are made fast to tubes through mechanical construction processes, thus eliminating the use of solder or other bonding materials. Ask for Publication 229. 923 Heaters, Hot Water Bell and Gossett Company 3000 Wallace Street Chicago, 111. HOT WATER SYSTEMS AND SPECIALTIES B & G INDIRECT WATER HEATERS -FOR STEAM AND VAPOR SYSTEMS Ratings below are based on 100 degree rise in three hours with boiler water temperature of 180 degrees or more . ' Description SINGLE COIL For residences of all sizes. Duplex apartments and small buildings. DOUBLE COIL For larger apartments, garages. medium sized factories'and office buildings. . TRIPLE COIL For heavier requirements. DOUBLE TRIPLE COILS No. Capacity Gallons - Max. Length Inches Max. Shell Coil- Shipping Width Openings Openings Weights Inches Inches Inches Pounds 30 30' 11% 554 40 40 554 ll52 52 66 66 182 82 100 120 100 120 22^4 144 144 25'/. 7% % 12 % 13 % - 15 1 29 1 39 1 40 1 42 1 46 160 160 12 lift 2 192 192 14V. lift 2 300 300 1954 lift 2 400 400 23% 11% 2 !% 53 1% 59 1% 78 1% 86 600 600 21% 15% 800 800 25% 15% 1000 1000 29% 15% 3 3 3 1200 1200 23% 29 SB1600 2000 1600 2000 29 29 4 4 '4 230 i 250 290 568 ! 642 716 B & G TANKLESS HEATER This B & G Tankless Type Heater has been designed to fulfill a need for a heater of unusual capacity that could be installed in boiler rooms lacking space for storage tanks. Size No. 12 20 30 For all Steam, Vapor and Hot Water Heating Boilers Heating Surface in Square Feet 12 20 30 Capacities in Gallons in 1 Hour Heated from 50 F to 130 F Boiler Water at 212 F 207 345 516 Boiler Water at 200 F 168 288 430 Boiler Water at 180 F 100 168 250 B & G THERMOCHEK Controls automatically the temperature of hot water storage tanks heated by indirect heaters. A simple, completely automatic device that eliminates lime and sediment formation in the heater coils. Sizes in. and 2 in. B & G MONOFLO FITTING This fitting is used on mechanically - circulated one-pipe hot water systerns. When installed in the main at each tadiator connection, it assures a balanced system with short cir cuits eliminated and all radiators receiving their full quota of hot water. No. V/4 ................................................. |l/2 .................................................. 2'"................................................... Size. Inches i/t B&G ORIFLO FITTING The Oriflo fit ting is for use on hot water radi ators. New or old gravity or forced circula tion jobs can use this device for accurately regulating the temperature drop through the radiators, thereby balancing the heating system quickly with minimum expense and with out shutting down the heating plant. 924 Bell and Gossett Company Heaters, Hot Water B & G TRIPLE DUTY SYSTEMS FOR HOT WATER SYSTEMS Size No. Recommended Capacities "Capacities Shipping Tank Gals, Sq-Ft. Weight Sizes per Hour E.D.R. Pounds 15 30 gals. 16 45 gals. 17 66 gals. 18 88 gals. 19 30 gab. 20 42-66 gals. . 21 66-88 gals. 30 35 40 50 30 40 50 1,500 1,500 1,500 1,500 3,000 3,000 3,000 152 153 155 159 158 161 165 22 66-120 gals. 70 3,000 183 23 120-180 gals. 100 3,000 198 24 180-300 gals. 140 3,000 213 25 300 to 400 gals. 26 WU to M)U gals. 27 5UU to bW gals. 200 266 333 6,000 6,000 6,000 445 465 fe SOS "Capacities in square foot of direct radiation are based on 200 Btu ' radiator emission with a 20 F. drop. . B&G BOOSTER Size' No. Face to Face Dimensions r T/S IV,' 8%' V y 8%' \2T Flange Size Motor 110 Volt 60 Cycle Normal Delivery Gallons per Minute Shipping Weight \W Screwed \W Flanged 2 " Flanged 3 " Hanged 1/8 hp. 15 at 2 ft. head 70 lbs. 1/8 hp. . 3u at ' It. head 80 lbs. 1/6 hp. 60 at 4>/2 ft. head 83 lbs. 1/3 hp. 100 at 5<A ft. head 135 lbs. B&G MOTORIZED VALVES These valves are guaranteed to stop the flow of water in the heating mains of hot water sys tems. They are used for zone control and in year around, in directly heated domestic hot . water systems. Operation is by a 60 cycle, A.C. 25-volt induc tion type motor. Series No. i% i% 2 2% 3 4 5 6 D & T SELF-FILLING, AIR-CUSHIONED TANK EQUIPMENT Self-Filling Air-Cushioned Tank Equipment consists of a D & T Air Tank and a D & T No. 500 "All In One Unit" which is a combination relief and pressure reducing valve, performing the double duty of relieving excess pressure and keeping the system filled with water. Description Single 1V* in. Main Single 1 x/i in. Main Single 2 in. Main Single 2Vz in. Main Single 3 in. Mam Single 4 in. Mam Single 5 in. Main Single 6 in. Main System No. 518 524 530 535 Capacity Sq Ft Radiation Up to 500 ft 500 to 800 ft 800 to 1200 ft 1200 to 1600 ft System No. 540 ` 560 580 600 Capacity Sq Ft Radiation 1600 to 2000 ft 2000 to 3000 ft 3000 to 4000 ft 4000 to 5000 ft ' D & T SIMPLEX TANK-IN-BASEMENT SYSTEM This system consists of an air-tight Compression Tank, Relief Valve (illustrated), Thermometer, Gage and Vacuum Breaking Valve. Made in 14 different sizes with capacities up to 5000 sq ft of radiation. 925 Shipping Weight Pounds 19 20 23 35 40 78 140 190 `Saw: Heating Systems, Hot Water H. A. Thrush & Co. Peru, Indiana THRUSH TANK IN BASEMENT SYSTEM Thrush System of Hot Water Heating provides an automatically controlled heating plant, operating with high ef ficiency at low fuel cost. Circulation is increased, resulting in even and quick heat distribution. Installation cost is reduced because small pipe and valve sizes are required when-Thrush System is used. Thrush System may be installed with either old or new Hot Water Heating plants. It converts a gravity type job into a Closed System with accelerated cir culation and increased heat transmission. Thrush Tank in Basement Systems are made in different types to care for hot water heating jobs of every conceivable kind, all providing the advantages of the closed system with controlled circulation. Each system is made in sizes to care for the needs of any job. It is possible to provide varying degrees of automatic operation, damper control, automatic .sys tem filling, automatic pressure relief, etc., to meet the demands of any job or to offset any competition. In all Thrush Systems the Thrush Pres sure Tank takes the place of the ordinary gravity of open expansion tank. It is near the boiler where it cannot freeze. It pro vides a reservoir to take care of water expansion and to avoid waste of heated water. Being under pressure, the system circulates more positively and rapidly, saving fuel. Easy boiling is prevented and a wide range of boiler temperatures from 120 to 220 F. may be carried without noise or boiling. This gives the job extreme flexibility of performance and the highest thermal circulation efficiency possible to secure. . No. 4. Differential Pressure Relief Valve for Hot Water Heating System is safe and dependable. It has a large metal diaphragm which actuates movement of a free working valve member--has no tightfitting guide. It is fully guaranteed when properly installed. Set to open at 28 lb. pressure, suitable for 1, 2, or 3 story buildings. Special adjustment up to 35 lb. Weight 12 lb. No. IS--Pressure Reducing Valve Tapped % In. No. 12. Pressure Reducing Valve pro vides automatic filling and maintenance of proper water supply in a Hot Water Heating plant. Large waterways. Work ing parts brass. Fully guaranteed against defects in workmanship and materials. Pressure setting suitable for 1, 2, or 3 story buildings. Weight 7 lb. 926 H. A. Thrush & Co. Heating Systems, Hot Water H. A. Thrush & Co. Peru, Indiana THRUSH FLOW CONTROL SYSTEM--For Automatic Hot Water Heating Every Boiler Burner Unit Hot Water Heating Plant should be equipped with Thrush Flow Control System because it makes the job heat quickly, maintains healthful tem peratures automatically, increases the efficiency of the burner, permits economical year 'round use for Summer-Winter domestic hot water supply and saves fuel. The water in the boiler is maintained at a constant temperature and cannot pass through the Flow Control Valve to the radiators when heat is not needed. When heat is required, the thermostat operates the Thrush Circulator, which quickly forces hot water through the Flow Control Valve to every radiator in the house, restoring room temperature almost instantly. Then the Flow Control Valve shuts off all further circulation, preventing overheating and attendant waste of fuel. Running time of burner is reduced. THRUSH WATER CIRCULATORS Silent, Efficient, Electric Motor Driven Water Circulating Pumps Thrush Water Circulators are correctly designed to lift the load of cold returns and assure instantaneous heat delivery. They are made in four sizes, as listed below. Motors are 110 V. 60 Cycle, A.C., Capacitor type, silent in operation and free from radio interference. No. Size 14 I in. 15 1 Vl in* 22 2 in. 23 3 in. Motor 1/10 Hp 1/6 Hp 1/6 Hp 1/4 Hp Gallons Delivery 25 per Min 50 per Min 75 per Min 140 per Min Radiation Capacity 500 sq ft 1500 sq ft 2500 sq ft 5000 sq ft Shipping Weight 53 lb 72 lb 74 lb 941b The complete Thrush Flow Control System consists of a Thrush Water Circulator of the proper size, a Thrush Flow Control Valve of proper size, a No. 12 Thrush Pressure Reducing Valve, a No. 4 Thrush Differential Pressure Relief Valve and a special Thrush Air Tight Pressure Tank of proper size. This system converts an open gravity job to a closed pressure system with automatic filling and maintenance of proper water supply, automatic relief of excess pressures, adequate provision for expansion when the water is heating and complete mechanical control of circulation. When used in conjunction with the regular thermostatic controls with which most automatic heating plants are already equipped, the heating plant becomes completely automatic, flexible and quick to respond to the slightest need for heat. THRUSH FLOW CONTROL VALVES PATENT No. 1,931,419 The Thrush Water Circulator and the Thrush Flow Control Valve used together provide complete circulation control as the Flow Control Valve works by pressure head generated by . the-Circulator. There are no complicated fittings. Instal lation is inexpensive and easy on old or new jobs. Flow Control Valve has expansion opening to provide for escape of excess pressure and elimination of air and gases. (Manually operated set screws permit dosing or opening permanently but are not needed for normal operation). No. Size . Connection Radiator Capacity Shipping Weight 114 1 in. Screwed 300 sq ft 31b 115 I'/z in. Screwed 1000 sq ft 91b 120 2 in. Flanged 1500 sq ft 191b 125 2'/j in. Flanged 2500 sq ft 261b . 130 -3 in. Flanged 5000 sq ft 39 lb . 927 Heaters, Hot Water Davis Engineering Corporation HEAT TRANSFER SPECIALISTS SINCE 1915 Branch Office: 90 West Street New York City *Bomccil General Office and Factory: Elizabeth, N. J. PRODUCTS--Davis Automatically Fired Boilers, Paracoil Storage Water Heaters, Instantaneous Water Heaters, Fuel Oil Heaters, Oil and Water Coolers, Distillers, Feed Water Heaters, Feed Water Filters and Grease Extractors, Steam Traps, Evaporators, Converters, Preheaters, Hot Water Generators, Condensers, Heat Exchangers Years of trouble-free service without excessive maintenance charges have been the aim in the design of Paracoil appara tus. Paracoil Heat Exchange Products are preferred by many leading industrial, naval and building engineers. Many large ships and famous buildings have Paracoil heat transfer equipment. Special heat transfer problems invited. Write for bulletin on products in which you are interested. PARACOIL INSTANTANEOUS U-TUBE TYPE WATER HEATER Ideal for apartment houses, hotels, etc. Connected below water line of boiler, heats water supply when fires are banked. Castiron or steel shell, heating elements of seamless drawn copper. Capacities 300 gal. and up (below water line installation) or 20 gal. and up (live steam installation). Catalog on request. PARACOIL STORAGE WATER HEATER For heating and storing hot water for apartment houses, office buildings, hospi tals, laundries, etc. Operates with boiler water, exhaust or live steam as heating medium. Steel plate storage water shell with removable seamless drawn copper heating coils. Maximum efficiency of heat transfer. Any pressures specified. Capa city 40 to 25,000 gal. per hour. Capacity tables, calculating data, etc. on request. Write for catalog. TUBULAR HEAT EXCHANGERS For cooling lubricating oil or water and similar heat exchange uses. Removable or non-re movable tube bundle as required. Transverse or Longitudinal Baf fling as required. Floating tube sheet and head construction or shell expansion joint compen sates for expansion and con traction strains. Built in single and multi pass types. Small space requirements. Write for information. PARACOIL FUEL OIL HEATER, TUBULAR AND COIL TYPES Rand System of Fuel Oil Preheating in Storage Tanks Efficient and compact, removable heating element, freedom from ex pansion and con traction strains. Designs permitting easy cleaning. Turbulent flow of oil assures high heat transfer. Unusually low pressure drop or friction loss. Variable baffle spacing gives vari able velocity in pro portion to change in viscosity. Hori zontal or vertical installation. Write for catalog. jWaraff nauumacao Section of Paracoil Tubular Heat Exchanger 928 Instruments The Bristol Company Pioneers In Process Control Since 1889 Waterbury, Connecticut Branch Offices Akron, Ohio Birmingham, Ala. Boston, Mass. Chicago, III. Denver, Colo. Detroit, Mich. Los Angeles, Calif. New York, N. Y. Philadelphia, Pa. Pittsburgh, Pa. St. Louis, Mo. San Francisco, Calif The Bristol Co. of Canada, Ltd., 64 Princess Street, Toronto, Ont. Bristol's Instrument Co., Ltd., Pomeroy Street. New Cross, London, S. E. 14 TRADE-MARK BRISTOL'S REO. U. 8. PAT. Office Recording Pressure Gages Recording Pressure Gage Model 40M For securing continuous day and night records of pressure or vacuum for steam, air, gas and liquids. Furnished with charts reading in pounds, ounces, feet, inches, metric or any other desired units for ranges from full vacuum to 12,000 lb per sq. in. Recording Indicating Thermometers For all commercial ranges from 60 F below to 1000 F above zero. Electric Indicating Thermometer indicates temperature at any number of distant points. Metameter for Telemetering Consisting of (1) a recording receiver in your office or other central place, (2) a transmitter at the far point where the measurement is made, and (3) a simple circuit of two small gage wires (or any existing telephone line) for carrying the electric impulses automatically sent out by the transmitter, the Metameter tells accurately and instantly how pressure, temperature, or flow is* fluctuating at any point a hundred feet or several thousand miles away. No interference with or from power, light or telephone lines. Easy to read 12 in. diameter chart,^with, wide open scale. D.C. or A.C.; 25 or 60 cycles; self-checking. Metameter Transmitter, Model MS6T Automatic Tempera ture Control A complete line of Auto matic Control Instru ments is available for temperatures up to 3000 F. These are suitable for application to steam, oil, . gas and electric heated equipment. Both electric and air operated models are furnished. Since Bristol makes both control instruments and automatic valves, it is able to develop the complete control system as a unit. It has the experience and facilities correctly to engi neer the system and to assume individual respon sibility for the success of the results secured. Free Vane Temperature Recorder Controller, Direct Reading Model SS40M Relative Humidity Recorder . Chart record shows at a glance the trend of humidity condition. Novel vapor-sensitive hygroscopic element. Special aging process assures sustained ac curacy. Eliminates Thermo-Humidigraph, calculation, and use of Model 4069 humidity tables. No water required. No fan used. Accurate below freezing tem perature. Light portable corrosion-resist ing case. Flow Meter for Steam, Liquids, Gas Employs orifice and mercury manometer system of measurement. Meter body is of forged steel, with stainless steel parts in side the mercury chambers. All connec tions are welded or mechanical. The stuffing box is of hardened stainless steel. Grease-packed and leak-tight. For working pressures up to 1000 lb. Special bodies available up to 3000 lb. Industrial Stem Thermometers With plain or red background.. Fixed thread, union connection or socket design. Straight form, or rear oblique, right side and left side angle forms. Wet- and Dry-Bulb Psychrometer Accurate and dependable instrument by which relative humidity or atmospheric moisture may be determined. Available in self-contained and distance types. 929 s' Instruments Brown Instrument Division of Minneapolis-Honeywell Regulator Co. Main Office and Plant Philadelphia, Pa. Equipment available through all Minneapolis-Honeywell Branch Offices as follows: Atlanta Baltimore . Boston Buffalo Chicago Cincinnati Cleveland Detroit Duluth East Orange Hartford Haverhill, Mass. Indianapolis Kansas City Louisville Milwaukee Minneapolis-St. Paul New York Omaha Peoria Philadelphia Pittsburgh Providence St. Louis San Francisco Springfield, Mass. Syracuse In Canada: Main Office and Factory: Toronto, Canada; Branches: Calgary and Montreal Distributing Offices in all other principal cities Brown Recording Resistance Thermometer Brown Instruments The extent to which air conditioning equipment is being used in office buildings, theatres, stores, industrial buildings, etc., has opened up a wide demand for indicating and recording resistance thermometers because the temperatures throughout these air conditioning systems should be checked periodically to get the best results at minimum operating cost. Indicating To obtain uniform conditions from modern equip ment, it is'necessary that the one in charge have a visual picture of actual conditions. If the individual units of the system are controlled automatically, the operator will know when this control is adequate and when it is not. Whether automatic or manual, the Brown Resistance Thermometer will detect all variations, allowing the operator to maintain the conditions as set forth in the specifications. Recording Uniformity of temperature and the consequent control of humidity depends on reliable facts obtained concerning wet- and dry-bulb temperatures. Controlling Brown Portable Thermometer Because the three-lead Brown Resistance Ther mometer is entirely independent of variations in lead resistance, variation in bulb location lengths, number of bulbs, etc., it affords an excellent means of obtaining reliable results. Bulbs may be placed at will or changed from one location to another; instruments may be moved about, and readings or records taken without any delay due to recali bration of leads, instruments or bulbs. In addition to Resistance Thermometers, the Brown Instrument Company manufactures: Thermometers Hygrometers Pressure and Vacuum Gauges Potentiometer Pyrometers Flow Meters CO2 Meters Tachometers Liquid Level Gauges See also Pages 1044-1049 930 Instruments Consolidated Ashcroft Hancock Co., Inc. Bridgeport, Conn. BRANCHES IN PRINCIPAL CITIES Makers of AMERICAN INDUSTRIAL INSTRUMENTS--Since 1851 Manufacturers of Indicating and Recording Gauges; Gauge Testers; "U" Gauges; Draft Gauges* Indicating and Recording Thermometers; Tachometers; Dial Thermometers; Pressure and Temperature Controllers; Electric Temperature Controllers; Pop Safety and Water Relief Valves; Steam Traps; Engine Indicators; Counters; Absolute Pressure Gauges. Also manufacturers of Bronze. Cast Steel and Forged Steel Valves, Locomotive and Engine Room Clocks; Barometers; Mercury Column Gauges; Steam Whistles; Hydraulagraphs; Gauge Boards Ashcroft American Gauges--Ashcroft American Recording Thermometers-- American Gauges are made in all sizes from Made for recording temperatures from 2to 12 in., for pressures from 8 oz to minus 40 to plus 1000 F. 25,000 lb and also for vacuum. Cases or equivalent C. Very flex ible connecting tubing up are cast-iron or cast to 200 ft. One size only to brass. The move: ments are Heavy accommodate 10 in. chart, with an effective scale Duty and all bear width of 3% in. ings are Monel Met Same case as for the al. Write for Cata log No. A-59. American Recording Gauge, so that all instru For Mercury ments are uniform in ap Pressure and Vacuum Gauges, "U" pearance when mounted Gauges, Draft Gauges and Mercurial on Gauge Boards. Ameri Barometers, write for Catalog B-59. can Indicating Gauges and American Recording Gauges--Ameri can Recording Gauges are made for all Dial Thermometers are also furnished in same case. Write for Catalog H-59. pressures from 15 in. of water to 10,000 lb. American Dial Thermom and for vacuum. eters--A m e r i c a n Dial They are made in one (mercury-filled) Indicating size only to accom Thermometer has theaccu- modate a 10 in. chart, racy of the standard glass having an effective tube thermometer and the scale width of 3% in. reading convenience of a The case is Die Cast dial face. Entire working with a dull black mechanism is made ofsteel, hard-rubber finish meaning long life. and with either bot Standard size of dial 6 tom or back connection. The pen-arm is and 12 in. Furnished with made of non-corrosive Monel Metal and is rigid connection or flexible of the inverted type. Operating instruc capillary steel tubing up to tions are lithographed on the chart plate so 200 ft long. For temperature ranges from that they cannot be lost. minus 40 to plus 1000 F. Write for Especially designed Seth Thomas clocks Catalog G-59. are used, and all customary time periods .can be furnished. . American Recording Gauges are equipped with the Time Punch which virtually makes each instrument a time clock, since a hole is punched in the chart whenever a reading is taken. Write for Catalog E-59. American Precision Temperature Controllers--Self-operated and simple in construction. For regulating tempera tures from 25 to 385 F. Under favor- able conditionstem perature will be held American Air Duct Thermometer-Designed especially for both warm and cold air ducts. Fitted with chromium plated frame, glass front. Fur nished with 9-in. or 12-in. within 1 deg. Sen sitive, rugged and . accurate. For hot water service tanks, water heaters, etc. Standard ranges carried in stock. Size of valve must scale, graduated 0-160 F. be specified. Write Write for Catalog F-59. for Catalog R-59. 931 Instruments Hays Corporation COMBUSTION INSTRUMENT SPECIALISTS SINCE 1901 HAYS DRAFT INSTRUMENTS Michigan City Indiana PRODUCTS--Dry Type Pointer Draft Gages; U-Tube, Direct Reading and Vernier Scale Draft Gages; Air Filter Gages; C02 and Draft Recorders, Flue Gas Analyzers (Orsata): Portable Combustion Test Sets; Draft Recorders; Boiler Panels; Ignition Velocity Meters; Portable Hand Operated Gas Calori meters. Recording Gas Calorimeters. INDICATING Hays Dry Type Pointer Gages for Draft, Pressure or Differential have Lug, wall or panel mounting. Any number of gages may be arranged compactly side by side. Critical accuracy is obtained from this fundamental type of portable inclined tube gage. Convenient reel for tubing. The B Dry Type Portable is accurate and rugged. Set up for service in 30 seconds. No liquids used. V Type Portable Inclined Tube Especially designed for indicating resistance through air filters. Air tight case will indicate differential pressure when connected to opposite sides of filter bank. B Gage for Air Fillers RECORDING The Hays "OTM Recorder is an outstanding instrument that will put the operation of any system of ventilating or air conditioning on a recorded engineering basis. It is available also in a two-pen, two-unit style in ranges from 0 to 0.5 up to 0 to 100 inches water and secondary pressures from +0.1 to 0 to - 0.4 up to 5.0 to 0 to 5.0. The Hays Super-sensitive "OHM Recorder (not illustrated) will record draft and pressure from 0 to 0.1 to 0 to 0.4 and pressure-draft from + 0.1 toOto - 0.1 toO + .05to0to - 0.15. Writeusfor special information on these two outstanding ^ir movement instruments. B Type Portable ' CONTROLLING Any range, any sensitivity of slack leather diaphragm may be built into the Hays Draftrol. Changes in draft, open or close electrical con tacts in the non-tiltingsealed mercury switches. We in vite correspondence on applications of the Hays Draftrol Gages. Draftrol STATIC PRESSURE AND AIR FLOW 932 Hays "07"' Recorder Instruments Illinois Testing Laboratories, Inc. 422 N. LaSalle Street, Chicago, Illinois TESTING ENGINEERS AND MANUFACTURERS "Alnor" Indicating Pyrometers--Portable and Stationary, "Alnor" Surface Temperature Pyrometers, "Alnor" Distant Reading Resistance Thermometers, "Alnor" Velometers (Boyle Type)--Air Velocity Meters. "ALNOR" (BOYLE TYPE) VELOMETER The Instantaneous Direct Reading Air Velocity Meter Heating, ventilating, and air conditioning engineers as well as equipment manu facturers, industrial engineers, or anyone who has need for an instrument to give quick, accurate air velocity information will find the Velometer an indispensible instrument. It is a direct reading instrument which gives accurate and instantaneous readings of the speed and direction of air motion measured in feet per minute. ' The instrument is housed in an attractive black bakelite case 5J4 in. x.5% in. x 2% in. in size and weighs approximately 2 lb. The air which enters through the meter, actuates a movement comprising a vane, control hair springs, pointer, and magnetic damping system. No mathematical calculations or stop watches are necessary to determine the velocity reading as the pointer indications are a direct measurement of air speed. The Velometer is furnished in two types: (1) the Shutter Type; (2) Tube Type. Standard double ranges 0-300 low range 0-3000 high range. Other special ranges higher and lower can be furnished. Shutter Type--The shutter type has a shutter which opens or closes the ports in the instrument case forchanging thescale range. To use the shutter type Velometer it is merely necessary to hold the Velometer with the ports in line with the air stream. Tube Type Velometer--The tube type Velometer is the same as the shutter type except that attachments are used with a suitable jet for the high scale readings. The air then enters or is drawn through this jet. With the tube type Velometer accurate velocity readings of the discharge or suction grilles, ducts or other restricted or small openings can be easily and quickly obtained. Various types of jets are obtainable each especially designed for special function. No. 2 Averaging Jet--In commercial work for ordinary duct openings or grille use, it is simpler to take average readings over a 4 in. circle and for this service the No. 2 averaging jet is offered. No. 5 and No. 6 Jets--Either bent or straight jets of this type having small orifices give exact velocities over a in. diameter surrounding the end of the jet. These jets are ideal for exploring the velocities through irregular shaped grilles, leaks in duct systems, and for measuring velocities of slotted grilles where other type of velocity meters cannot be used. Duct Jets are offered for readings with in ducts. The duct jet is in effect a double jet using two tube attachments and two meter fittings. The air enters the meter through one side of the jet and is returned and discharged back into the duct through the other side of the jet. Write for Literature Fig. 1--Showing Tube Type Velometer with No. 5 Angle Jet taking air velocity of grille Fig. Showing Tube Type Velometer with Duct Jet taking readings directly in the duct. Duct Jet furnished 18 in. or 86 in. long 933 Instruments Leeds & Northrup Company General office and Works: 4941 Stenton Avenue, Philadelphia, Pa. Cricago St. Loins Los Angeles San Francisco Branch Offices: Cleveland Pittsburgh Houston Detroit Tulsa RUGGED, NULL-TYPE INSTRUMENTS THAT ARE RELIABLE Records from I to Id points on a single stripchart. Extremely open record. Con operate signals. (About 1/16 size) Model R Moeromax Recorder Records 1 or t points on a roundchart Has extremely readable dial. Can operate signals. (About l/16th size) Switchboard Indicator Hand-operated. Can be connected through selector switches to any number of points. (About 1/lSth size) Electrical Thermometers for Air Conditioning Electrical Instruments for the Heating Plant No method for measuring temperatures The facts needed to operate a modern fits the specific needs of air conditioning as heating plant so as to save fuel, to protect does the three-lead null-type resistance equipment, and to operate efficiently at thermometer method. It is independent varying loads are provided reliably by of distance and disregards all tempera tures except those right at detector loca tions. The detectors (resistance thermo meter bulbs called Thermohms), can be placed anywhere--in rooms, air ducts or water lines. They are connected by rugged L & N instruments. Readings can be indicated or recorded or both. Re corders can be equipped to operate signals or alarms that warn the operator of extreme conditions. In some cases the instruments control automatically. simple electrical wiring to instruments at a central location. Instruments may be: Micromax Recorders, Model S for up to sixteen Thermohms: Micromax Model R, for related pairs such as wet and dry bulb; indicators with switches for any number of Thermohms; or indicating and recording combinations. Micromax Model S. provides a per manent record of conditions at from 1 to 16 points on one wide-scale chart. Micro max Model R concentrates on conditions at one point, provides a permanent record, and has a giant indicating dial that can be read at a glance. The switchboard in dicator provides intermittent checks on This equipment is fundamentally re conditions at one or several points. liable. Instruments and Thermohms are In the heating plant, L & N measuring, highly responsive, yet rugged in construc signalling or controlling equipment is tion. A complete system is easy and economical to install, regardless of dis 'Nused for: tances. It is easy to operate and demands minimum maintenance. Thermohms and instruments are interchangeable, and can be replaced without disturbing wiring or returning anything to the factory. Metermax Combustion Control. Furnace Pressure Control. Smoke Density Analysis. Flue Gas Analysis (Per cent COj). Flue pas Temperatures. L & N Resistance Thermometers make it possible to operate efficiently; to main tain comfort or correct process atmosphere constantly . . . . to get maximum return on the entire conditioning investment. Steam and Water Temperatures. Boiler Furnace Temperatures. pH--Alkalinity (or Acidity) of Water. Electrolytic Conductivity of Water. Percent Leakage of Cooling Water. T-362 934 Instruments The Palmer Company 426 Clay Street . Cincinnati (St. Bernard), Ohio Manufacturers and Originators--"Red-Reading-Mercury" Thermometers PRODUCTS--Indicating Thermo meters with the RED column. "RED-READING-MERCURY" was originated by Palmer. We hold the basic patents on the reflected RED color. See illustration. A strip of red glass is drawn into the tube and when the mercury column rises, in the tube, the RED color is reflected onto it. Nothing is done to harm the purity of the mercury. Instruments for Testing AIR CONDITIONING EQUIPMENT When air-conditioning equip ment is installed, the contractor must have reliable and accurate instruments to make tests. Only with such instruments can he give satisfactory results. SLING PSYCHROMETER This, pocket style instrument can be carried anywhere and quick tests made.. Wet and drybulb tubes guaranteed accurate. Furnished with metal case, leather covered. INDUSTRIAL STYLE THERMOMETERS Furnished in all sizes ` and with STRAIGHT or various ANGLES styles. With Fixed taper thread, Union connection, Separable Socket or flange fit tings. With the RED column, these ther mometers are very easy to read. ACCURACY GUARANTEED ; MADE STRONG AND DURABLE. No. SB7 ASPIRATING PSYCHROMETER (This is not illustrated). The Aspirating Psychrometer for test ing humidity is recommended where readings of greatest pre cision are required. Contains small motor and blower so the air is blown over the wet and dry bulb thermometers. Two styles: Battery operated for use where there is no electric connection. Electrically oper ated, to plug in on No. usoo light circuit. With carrying case; neat, compact, light weight. Very handy instru ment. . OUTDOOR THERMOMETERS Here is an ideal thermometer for use outdoors'or inside. The metal case is of bronze which will not corrode. Graduated scale, giving very accurate tempera ture. White Duco finish. Nickelplate or Chromium finish also Rjrjj ` "'IIS' THERMOMETERS I It is helpful to carry a 1 pocket test thermometer, so I j that it is available at any 0 time. This is a reliable, guaran- teed accurate thermometer. [ Easy to read with the RED 1 column. . 1 furnished. With the RED Repairs--We can repair column, it can be .seen, a great oft 9 all makes of mercury ther- distance. "Pi h mometers and furnish "Red- Other styles of Wall Ther jit Reading-Mercury" atnoextra mometers as well as Laboratory cost. The type of repair styles furnished with the RED sell work we do will add years to column. the life of the thermometer. Write for FREE catalog No. No.eieo A trial Order will convince 200-C. . Thermometer you. i ' j ' 1! j i fc No. 1SS40 935 Instruments ^cujlcr Irutrwmait CornpnnieA Rochester, N. Y., U. S. A. NEW YORK CHICAGO BOSTON IN CANADA--Tatlob Inbtbuhxnt Companies or Canada. Ltd., Tobonto PHILADELPHIA PITTSBURGH CLEVELAND LOS ANGELES INDIANAPOLIS SAN FRANCISCO ST. LOUIS CINCINNATI TULSA Manufacturing Distributors in Great Britain, Short & Mason, Ltd,, London DETTROIT ATLANTA MINNEAPOLIS Manufacturers of Taylor Instruments for Indicating, Recording and Controlling Temperature, Pressure and Humidity Taylor Recording Thermometers--Tem perature ranges and time requirements vary great ly in heating and venti lating work. Taylor Re corders are made in scale ranges and time periods to meet these needs. In their handsome new . cases, these instruments are beautiful and efficient, par ticularity adapted for heating and air conditioning appli cations. They may be had for surface or flush mounting. When set in panel boards, the polished flanges make an ef fective installation. Write for special information suit able to your needs. Taylor Electric Contact Tempera ture Control---These instruments com bine in the same case an electrically- operated temperature controller with an indicating thermometer. One tube system operates both units. . The New Taylor "Fulscope" Re cording Con troller--An air-operated controller so versatile that practically any character of process con trol can be ob tained, regard less of time lag in apparatus, ' by a. simple screw driver adjustment on a graduated dial--without requiring a skilled oper ator or interruption of service. Vast improvements in entire mechanism. Easily changed from direct to reverse-acting, or vice-versa--no extra parts. Compensates for fluc tuations in air-pressure supply. Die-cast case; dust-, moisture-, and fume-proof. " Available forms: for controlling tem perature, pressure, temperature and pres sure, rate of flow, liquid level. Where extreme load changes or badly balanced operating conditions exist, the Taylor " Dubl-Response Control Unit" is the only positive means of maintaining control-point. Write for literature. Taylor Type-P Controller--A compact and very sensitive controller, ideal for air- ducts, air-washing zjsgk machines, cooling mfan . j~j*T rooms and similar applications. Uses compressed air as an fj wM&aBffJ actuating medium. Taylor Self-Acting Temperature Con troller--Adapted for use on hot-water storage tanks, etc. It is "self-acting" in that it requires no auxiliary motive power, such as compressed air, to open and close the steam valve. As heat is ap plied to the bulb, the volatile liquid inside sets up a vapor pres sure proportional to the temperature. This pressure is transmitted to a "stack" of metal diaphragms attached to the upper end of the valve stem, thus moving the valve disc toward the valve seat. The valve can be closed at any desired 936 Taylor Instrument Companies Instruments temperature, or a throttling action can be obtained. Not practicable on pipe lines having steam pressure over 125 lbs. Should be installed in a vertical position on top of a horizontal line. Operating ranges 110 deg. to 170 F., 130 deg. to 190 F., 170 deg. to 240.F. or 220 to 280 F. as specified. Taylor Dial Thermometers can be used for ab ducts or any appli cation where it is desirable to have temperature read ings at some dis tance from the thermometer bulb, as in a central con trol room. Can be read at a glance as easily and quickly as a clock or steam gage. Taylor Thermom eters for Air Ducts, Etc.--The Taylor line of industrial thermometers presents many styles and scale ranges with bulbs for every application. Suit able for air ducts, kiln tem peratures and oven tem peratures. For detailed information, write direct, mentioning your require ments. All these Taylor Industrial Thermometers have lens-front glass tubes, giving great magnification to the liquid, making it easy to see and read. Taylor Sling Psychrometer--The advantage of this form of Wet-and- , Dry-Bulb Hygrometer over ' the stationary form -is the facility with which tests can be made and the accuracy of the readings obtainable, as in whirling the bulbs they are subjected to perfect circu lation. Consists of two ac curate etched stem ther mometers mounted on a diecast frame, with the bulb of one covered with a wick to be moistened. These thermometers have scales of 0 to 100 F, gradu ated in Yi degree divisions. A copper case protects the tubes when not in use. Taylor HamptonModel Humidiguide (DirectReading)--A hygro meter giving-direct humidity percent ages, in a smart modem case suita ble for home, office or public buildings. Finish is satin black with chrome trim. The Permacolor Thermometer is filled with non-fadine. easv-readine red liquid. Taylor Re cording Hy grometer-- This instru ment records both wet- and dry-bulb tem peratures on the same chart in different colored inks, making com parison very easy. Type shown above with motor-driven fan for con ditioned rooms or passages in which circu lation is poor. Can be supplied without fan for installations where circulation across bulb is good. Taylor Anemometer--This instrument is ideal for measur ing air velocities with the fan revolutions indicated on the dial. Available in various models for a wide range of air speeds and registration limits. Taylor Humidi guide--A hand some small hygro meter for the wall of the home, office, school or other building where a neat, easy-reading and inexpensive instrument is de sired. It is selfcontained, requir ing no charts or separate tables. Frame is Mahogan y Bakelite. United States Gauge Co. 44 Beaver Street, GAUGE CQ New York, N. Y. Factory at Sellersville, Pa. Makers of Quality INDICATING AND RECORDING PRESSURE GAUGES All Sizes and Types for Every Purpose . U. S. GAUGES--U. S. Gauges are made in all sizes from 2 to 12 in. inclusive for pressures from 1 lb. up to 50,000 lb., and for vacuum. Cases may be cast-iron, cast brass, drawn steel and drawn brass for wall mounting or flush mounting. For severe service long wearing hardened steel or bushed movements may be supplied. For service on Steam Heating Systems-- Steam Gauges. Compound Pressure and Vacuum Gauges. . Retard Gauges. Compound Retard Gauges. . Steam Gauges with Internal Siphons. For Hot Water Heating Systems-- Altitude Gauges. Tank-in-Basement Gauges. Altitude and Pressure Gauges. Combination Altitude Gauges, and (a) Bimetal Thermometers. (b) Glass Tube Thermometers. (c) Vapor Tension Distance Type Thermo meters. Glass Tube Hot Water Thermometers. U. S. RECORDING GAUGES--U. S.''Recording Gauges are made in 8M, 10 and 12 in. sizes for pressures from 1 lb. up to 50,000 lb., and for vacuum. Cases may be cast-iron or cast brass for wall rtjpunting or flush mounting.' Pen arms are made of non-corrosive metal. 'Especially designed clock movements are used. Charts can be furnished for customary time periods. U. S. DIAL THERMOMETERS--U. S. Dial Thermo meters are of the vapor tension type with open scale reading in the central- and upper portion of the scale. Cases may be cast-iron, cast brass, drawn steel or drawn brass for wall mounting or flush mounting. Supplied in all sizes from 2 to 12 in. inclusive, for temperature ranges from 40 F. to 800 F. Furnished with rigid connection bulb or with flexible capillary tubing up to 100 ft. long. 938 Insulation The Agasote Millboard Company Trenton, New Jersey Manufacturers of Quality Products Since 1909 THE WEATHERPROOF INSULATING AND BUILDING BOARD Homasole at Home--Protection from the Elements Unnecessary chart shows that at a wind velocity up to 40 miles per hour, 18 to 112 times more air passed through the other boards tested than through Homasote and at higher velocities, the infiltration through these other boards increased in a much greater proportion. Homasote has very high moisture resistance, according to tests made by the Robert W. Hunt Co., Chicago. Refer ence to the chart shows that the other boards took up 101 per cent to 274 per cent more moisture. HOMASOTE WEATHERPROOF IN SULATING AND BUILDING BOARD Homasote can be used as a combination insulating and structural material. Im portant facts in the selection of an insu lating material are it's efficiency as an insulator, its structural strength, its mois ture resistance, its plaster adhesion, its re sistance to air infiltration, whether it is fire-retardent and the cost of installation and upkeep. Homasote is manufactured in BIG sheets, 8 ft x 14 ft, 8 ft x 12 ft, 6 ft x 12 ft, and even multiples thereof, making it pos sible to cover the average size wall in one piece. . It may be used on the exterior of a building even without painting. Comparative tests on air infiltration are shown below. These tests were made by the Lewis Institute, Chicago, 111. The A H it! AS >T \ .>o 7" 2 loo 90 1 1 2 80 I 70 L 7 7 7 Z7 7 7 < X ft O 50 L tA 2 s 7 1 f z ao U 5" O *0 20 SO 40 30 OX>a0 90 M0llOI3oa0 INFILTRATION OF AIR Ctl. FT. HR HOUR FIR SQl FT. HOMASOTE TYPE MN FIRE- RESISTING INSULATING BOARD Homasote Type MN provides not only insulating value but also protection from fire. It is made in 3d> in. and J4 in. thick ness, and in sizes of 4 ft x 7 ft, 4 ft x 8 ft, 4 ft x 10 ft, 4 ft x 12 ft, and 4 ft x 14 ft. In the % in. thickness, Homasote Type MN takes a one hour fire rating. The thermal conductivity of Homasote Type MN is 0.43 Btu per hour, per square foot per 1 deg Fahrenheit, per inch thickness. It is ideal for air conditioning ducts or for wall, floor or roof areas in fire zones. The insulating value of Homasote Type MN protects the studding behind it in a hot fire, and Homasote Type MN will not shatter if water is applied to it when hot. Write Direct to The Agasote Mill board Company, Trenton, N. J., for samples and descriptive literature. 939 Insulation Armstrong Cork Products Company Building Materials Division - Lancaster, Pennsylvania Albant Atlanta Boston Buffalo Charlotte Branch Offices . Chicago Cincinnati Cleveland Dallas Detroit Houston Indianapolis Jacksonville Kansas Cm Louisville Milwaukee Minneapolis New York Omaha Pittsburgh Rochester St. Louis Representatives John R. Iivesey...... ...... ......................................Baltimore, Md. Capital City 8upp!y Co............................Charleston, W. Va. Stearns-Roger Mfg. Co____________ __________Denver, Colo. Fischer Cement & Roofing Co___ _______Little Rock, Ark. Gay Engineering Corporation_____ Angeles, Calif. Fischer lime and Cement Co.. Inc________ Memphis, Tenn. H. T. Steffee--.--_________________________New Orleans, La. John R. Livesey____ _Philadelphia, Pa. Asbestos Supply Company-----John R. Livezey______________ San Angelo Bldg. Material Co. Van Fleet-Freear Co_________ Asbestos Supply Company....... Asbestos Supply Company.___ Asbestos Supply Company____ John R. Livesey............. ............ .............. Portland, Ore. ........ ....... Richmond. Va. ___ Ban Angelo, Texas .San Francisco, Calip. _______ .Seattle, Wash. ...........JSpokane, Wash. ________ Tacoma, Wash. ....... Washington, D. C. For detailed technical information, samples, and descriptive literature, ask any office or representative PRODUCTS--Armstrong's Corkboard, Armstrong's Cork Covering, Arm strong's Vibracork, Armstrong's Corkoustic, Armstrong's Temlok, Armstrong's Temcoustic, Armstrong's Insulation Sundries. Corkboard Sizes Armstrong's Corkboard is furnished in rigid boards 12 in. by 36 in., 12 in. x 32 in., 18 in. x 36 in., 24 in. x 36 in., and 36 in. x 36 in., in several thicknesses: 1 in., 1in., 2 in., 3 in., 4 in., and 6 in. Insulating Efficiency The thermal conductivity of Arm strong's Corkboard, depending on the density, is 0.27 to 0.29 B.t.u. per hour per inch thickness at 90 deg F mean tempera ture (U. S. Bureau of Standards). The. value of adequate and efficient insulation is covered in the-text section of this book (Chapter 5) and the tables on pages 112 to 124 indicate the savings which can be effected by using 1)4 in. or 2 in. of corkboard in standard wall and roof con struction. The reduction in heat loss amounts to from 50 per cent to 75 per cent. This means that an adequate thickness of corkboard on walls and roofs reduces the heat wasted, and, therefore,. the heat re . quirements of the house by 25 per cent to 40 per cent. Air Conditioning An adequate thickness of corkboard in sulation is essential for any air con ditioned room or structure. Insulation reduces the amount of heating or re frigerating equipment required to produce "desired temperatures and is highly impor tant to the satisfactory and economical . control of humidity conditions. The insulation of air conditioning equip ment assures economical and efficient operation by minimizing refrigeration losses. De-humidifying chambers and ducts as well as pumps and brine storage tanks may be insulated with Armstrong's Corkboard. The economies resulting from the application of Armstrong's Cork Covering to all cold iines repay the cost of the insulation and assure additional refrigeration savings. , v The elimination of noise and vibration, transmission is of primary importance in air conditioning work. Armstrong's Vibra cork, made in three densities, is ideal for this purpose. It does not take a set, is not affected by atmospheric moisture, and will not deteriorate in service. Products--Information Additional Armstrong insulating and acoustical products especially suited to heating, ventilating, and air conditioning work include: Armstrong's Corkoustic. Armstrong's Temlok. Armstrong's Temcoustic. Armstrong's Insulation Sundries. For aid in the solution of any technical problems involving insulation, isolation, or acoustical treatment and for literature and prices, get in touch with an Armstrong branch office or representative or the Armstrong Cork Products Company, Building Materials Division, Lancaster, Pa. 940 Insulation The Eagle-Picher Lead Company General offices: Temple Bar Building, Cincinnati, Ohio Offices in All Large Cities EAGLE INDUSTRIAL INSULATION The Eagle-Picher Lead Company manu factures a complete line of industrial in sulation materials, effective for a com plete range of temperatures. Representa tive products are: Eagle Super "66" Plastic Insulation For application on practically all forms of heat producing and heat transferring equipment. "Springy ball" construction provides remarkable heat-saving efficiency up to 1809 F. Easily applied with a trowel. May be applied on any clean surfaces. Great coverage--60 sq. ft. 1 in. thick per 100 lb. 100 per cent reclaimable. Eagle Blanket Insulation Eagle Insulating Wool felted and se cured between metal fabrics. For large sur faces where tempera tures reach as high as 1200 F. Available in "6f quickly ap- flexible or rigid form. JStASSt." Easy to cut and fit. Sizes--2 ft x 4 ft and 2 ft x 8 ft. Thick nesses range between 1 in. and 8 in. Eagle Asbestos Cements Inexpensive asbestos fibre cements of good mixing, trowelling and adhesive properties. For temperatures up to 1000 F. Eagle Insulseal . (Waterproofing Cement) Durable coating designed to protect all kinds of insulation from moisture, water, air infiltration, fumes; from vibration, abrasion. Ready mixed, easily and quickly applied. , Other Products Eagle . "99" Finishing Cement, Hair Felt, Pipe Covering and Blocks (all types), Insulating Wool, Boiler Setting Cement. EAGLE HOME INSULATION The Eagle-Picher Lead Company manu factures two types of "mineral wool" in sulation for homes: (1) in granulated form for pneumatic application in new and existing construction. (2) in bat form for new construction. Both types are wall-thick, non-structural, extremely light-weight, non-cor rosive, fire-proof--with thermal conduc tance (in applied thickness of 3)4 in.) of only 0.074 Btu. (The over-all con ductance would be considerably lower). Eagle Home In sulation keeps homes cooler in summer (12 to 15 deg cooler than outdoor tempera tures), and warmer in winter (fuel Eagle Insulating Wool eatily saving ranges be bloom into epacee between tween 10 and 40 wall etuddinge per cent). For Pneumatic Application In granulated form, Eagle Insulation is blown into hollow spaces between wall studdings and between joists in the attic floor by a special pneumatic process. No building alterations are necessary, whether the house is of frame, brick or stucco con struction. No mussing up inside. Work is done by skilled contractors, licensed by Eagle-Picher. Bat Form Eagle walUkiek bait quickly installed in nets conetruction Eagle Insulat ing Bats are rec tangular pads 15 in. x 18 or 23 in. x in., designed to fit snugly be tween studding and joists. Irregular spaces around doors and windows filled by cutting bats to exact size. Data and Specifications For complete specifications and technical data on Eagle Industrial Insulation, see Sweet's Engi neering or Power Plant Catalog. . Data and Specifications For complete specifications and technical data on both types of Eagle Home Insulation, see Sweet's Architectural Catalog. 941 Insulation Alfol Insulation Company Incorporated Chrysler Building New York, N. Y. Agents in Principal Cities INSULATION /or Fans Turbines Blowers Dehumidifiers Pumps Air Conditioners Ducts Boilers, Pipes, etc. Houses, Buildings, etc. At temperatures up to 1250 F. Patented in 34 Countries INSULATION for Refrigerators Refrigerator Cars Refrigerator Trucks Refrigerator Boxes Refrigerated Rooms etc. Ships Ovens Ranges Tanks Stills Alfol consists of single or multiple sheets of pol ished pure aluminum foil installed between wail studs, furring strips, ceiling joists or roof rafters. When heat tends to flow through such insulated structures, 95 per cent of radiant heat is reflected back toward its source. In summer, stifling outdoor heat is driven off. In winter, practically all sup plied heat is retained in the house where it is needed. The reflection of heat is a revolutionary principle in insulation engineering which has won wide spread recognition and acceptance by engineers and scientists throughout the world. Alfol is now ' Warm, comfortable cozy rooms-- No drafts Cool, comfortable living quarters extensively used by many of the largest manufac turing and industrial plants, U. S. Navy, and others, as well as in houses and buildings of every kind and size. Alfol will save up to 75 per cent or 80 per cent of the heat loss that would occur through an uninsulated house. It consequently costs less to heat an Alfol insulated home. Many owners report over one-third saving in fuel costs. Alfol is installed only by Authorized Applica tors. All work is done in . strict accordance with Alfol Standard Speci fications. Alfol Insulation Company, Inc. Insulation Alfol Insulation Company Incorporated . Data on Heat Savings Effected by Alfol Construction Heat Transmission. B.T.U./Hr./Sq. Ft./F. Not Insulated 1 layer ALFOL 2 layer ALFOL Heat Transfer Stopped--% 1 layer ALFOL 2 layer ALFOL Wood Stud Wall--4-in. studs............................. 0.26 0.12 0.09 53% 65% 12 in. Brick Wall--Furred.................................. .25 .11 .09 56% 64% Open Attic Floor................................................ .69 .17 .12 75% 83% Wood Shingle Roof................... ......................... .47 .15 .11 68% 77% Concrete Roof--8-in. slab--suspended ceiling.... .33 .14 .10 58% 70% Slate, 1 lie or Composition Shingle Roof.............. .56 .16 .12 71% 79% These Coefficients are computed from the results of tests conducted on actual wall sections by Prof. Gordon B. Wilkes, M.I.T. and by Prof. F. B. Rowley, U. of Minn. They Include the heat loss thru studs, joists, rafters, etc. Consequently, they give an accurate measure of the heat loss in an actual insulated structure. ALFOL ADVANTAGES Alfol is non-porus and has no capillarity. It cannot UNAFFECTED absorb moisture. Moisture infiltration in non- BY metallic insulations increases conductivity frequently DAMPNESS as much as 20 per cent. Such variations in con ductivity cannot occur in Alfol. INSULATING EFFECT Transmittance coefficients .(see table above) are determined from tests made on actual wall sections insulated with Alfol. They accurately measure Alfol's insulating effect including the heat loss through and around studs. Published coefficients for other materials are based on 12 in. x 12 in. panel tests--materials preheated in "bone-dry" condition and at specified densities. They do not include the heat loss at studs, nor the effect of moisture infiltra tion, variation in density, thickness, etc. Many noted authorities on heat transfer recognize that the performance of alfol in actual use is unexcelled. DUST AND DIRT cannot appreciably affect Alfol's uni formly high insulating value. FIREPROOF, CLEAN AND SANITARY No Heat Storage Capacity--Preheats or cools in approxi mately one-fourth the time required for other insulations. Alfol Metal-Jacketed Pipe Lines Fibre Speeer Ship* Sheetiun? Alfol Roof Insulation Keeps Houses Cooler in Summer and Warmer in Winter Alfol Applied Between Roof Rafters Reduces Heat Loss Over 80 per cent . Extra Living Quarters, Just as Tenantoble cs Any Other Part of the House, May be Obtained by In sulating Attic Roofs with Alfol Aluminum Foil Does Not Tarnish 942 TAif Photo Clearly Shows How Alfol Stops Cold Air Leaks Around Windows and at Studs Recessed Radiators Give off About 16 More Heat When Insulated With Alfol . Fibre Specer Alfol is Flanged on Edges and Nailed to Face of Studs, Joists or Rafters, Through Fibre Spacer Strips Alfol Reflects Heat as a Mirror Reflects Light 943 . Insulation The Celotex Corporation Boston, Mass. Minneapolis, Minn. Philadelphia, Pa. 919 N. Michigan Ave., Chicago, 111. Mills: NEW ORLEANS, LA. Branch Sales Offices: (SEE TELEPHONE BOOKS FOR LOCAL ADDRESSES) Denver, Colo. New York, N. Y. Cleveland, Ohio Los Angeles, Calif. St. Louis, Mo. Seattle, Wash. Portland, Ore. Spokane, Wash. Tacoma. Wash. Stdnby. Australia Paris. Prance London, England OeiloteX Buenos Aires. Argentina Durban, South Africa BRAND INSULATING CANE BOARD (Reg. U. S. Pat Off.) Builds - Insulates - Decorates - Subdues Noise Building Board Lath Sheathing Board Finish Plank Tile Board Adhesires Batten- Strips Hard Board Tempered Hard Board CELOTEX PRODUCTS: Black Tempered Hardboard Vaporproofed Low Tem perature Insulation Tempered Concrete Ferox Insulating Form Board Panel Board Studio Board Hardboard Tile (Tempered) Roof Insulation Protection Course Insulation Blocks Ornaments and Mouldings C-X Wallboards Vaporproofed Roof Rock-Wool Products Insulation Celotex Cane Fibre Insulation In the manufacture of Celotex, long tough fibres of bagasse (cane) are properly refined, thoroughly sterilized, effectively water-proofed, firmly felted and securely interwoven to produce large boards of maximum strength consistent with the light weight necessary to assure high heat stopping value. The " largest board in the world" is produced at Marrero, La., 12 ft wide and 1000 ft long! Commercial sizes are cut from this immense board by means of highly efficient automatic machines. Careful technical control assures uniform high quality. The thermal conductivity of Celotex is 0.33 Btu per hour, per square foot, per 1 degree Fahrenheit, per inch thickness (based on a density of 13.5 lbs per cubic foot and a mean temperature of 70 F.) Tests conducted at Armour Institute of Technology and at recognized laboratories confirm this figure. The Celotex Corporation maintains an engineering and research staff which is available for investigations of all types of insulation installations. Engineers are in vited to address their problems to The Celotex Corporation, Chicago, Illinois. The Ferox Process The Ferox Process (patented) is exclu sive with Celotex. All Celotex cane fibre products are manufactured under the Ferox process (patented) and therefore efectively resist damage by Fungus Growth, Dry Rot and Termites (white ants). The Ferox Process is not a surface treat ment--it is integral. The chemical com plex used is insoluble in water. It is non-volatile--odorless--permanent. Celotex Building Board The original cane fibre insulation. Neu tral tan color. Two-surface utility. One side sanded; the other with a Tapestry texture. Size--4 ft wide, and 4, 5, 6, 7, 8, 834, 9, 934, 10, and 12 ft long. 34 in. and 1 in. thick. . Celotex Tile Board An attractive wall and ceiling treatment. Type Double A has an interlocking re versible bevel joint; smooth and tapestry textured surfaces alternated if desired. Suitable for all types of design. May be applied over existing walls and ceilings or as a 'hew finish. Type A has beveled square edges; otherwise it is the same pro duct as Type Double A. Neutral tan color. Also furnished in several well chosen tints to simplify the task of suitable decoration. With Type Double A Joint-- 34 in. thick only--with % in. and 1 in. furnished on special order. Sizes range from 6 in. x 6 in. to 24 in. x 48 in. Celotex Finish Plank--34 in. thick; 6 in., 8 in., 10 in., 12 in., and 16 in., wide; 6, 7, 8, 9, 10, and 12 ft long.. Long edges Beveled and Beaded. Furnished with Type Double A, reversible bevel joint whereby either side can be exposed, thereby making possible a wide range of unusual designs. . 944 The Celotex Corporation Insulation Celotex Lath A natural bond for plaster--a con tinuous plastering surface providing special resistance to lath cracks--eliminating lath marks--beveled edges to reinforce plaster --patented. Shiplapped joints (see dia gram). Size: 18 in. x 48 in. 3^ in., ^ in., and 1 in. thick. CELOTEX PIASTER TT v-v * [M Celotex Sheathing Board Full Thickness, sanded or unsanded. Insulation and structural strength. May be used with standard frames. 34 in., % in., 1 in. thick; 4 ft wide; 4, 5, 6, 7, 8, 834, 9, 934, 10 and 12 ft long. Celotex Vaporproofed Low Temperature Insulation A moisture - proofed, water - proofed, vapor - proofed low density insulation. Each block encased in a sealed membrane. For all low temperature requirements, in cluding Coolers (Beer, Meat, Creamery, etc.), Fruit and Vegetable Storage Rooms, Packing Plants, Fur Storages, Air-Con ditioned Spaces, General Cold Storage Rooms, and Freezers. Conductivity 0.30 Btu per inch--odorless. Ferox-treated. Sizes: 18 in. x 18 in., 18 in. x 36 in., 9 in. x 36 in. Thicknesses: 1 in., 13^ in., 2 in., or any multiple of 3^ in. Celotex Rock-Wool Products Highly effective wall-thick insulating material made from Molten Rock. Abso lutely incombustible, vermin-proof and permanent. Batts, wall thick, fit between studs and rafters. Light in weight (about 13^ lb per sq ft). Size: 15 in. x 23 in. Loose and Granulated available to place into open spaces in walls and floors. Celotex Roof Insulation . Celotex Ferox Insulating Protection Course Waterproofing in some form is essential to the stability and efficient performance of many structures. Bituminous or mem brane waterproofing is generally applied to areas exposed to hydrostatic pressure or conditions of dampness and moisture. Foundations and floors of buildings, tun nels, subways, and other construction below ground surface are frequently water proofed. Swimming pools, reservoirs, re taining walls, bridges, and sumps or pits are similarly treated. It is customary to protect bituminous floor waterproofing from damage by heavy traffic, and waterproofing on foundation walls from abrasion by back fill. Practi cally all construction specifications defini tely require protection courses where water proofing or dampproofing is used. Celotex Ferox Insulating Protection Course size: 22 in. x 47 in.; thicknesses, 3^ in. and 1 in. Preferred as insulation over wood, con crete, steel, unit tile and poured gypsum roof decks. Size 22 in. x 47 in. Full thickness J4 in. Also furnished laminated from 2 to 8 plies. Celotex Vaporproofed Roof Insulation, Ferox treated, of special low density Celotex encased in vapor proofing membrane. Dependable Service The Celotex Corporation distribution and service facilities cover the whole United States and 82 countries overseas. This world-wide organization includes trained insulation engineers who are at your service whenever some unusual in sulating problem or project is before you. Authoritative data, technical notes and specific material on thermal or sound insu lation are available on request. Write to the Celotex Service Bureau, 919 North Michigan Avenue, Chicago, 111., for special problems. 945 Insulation Ehret Magnesia Manufacturing Co. Valley Forge, Pa. HEAT AND COLD INSULATIONS HEATING--Ehret's 85% Magnesia, Air Cell Coverings, No. 18 Insulating Cement. AIR CONDITIONING -- Nlcolfelt thermal and sound insulation, Ehret's Hair Felts, Cork Products. PLUMBING --Ehret's Wool Felt Pipe Covering, Anti-Sweat Pipe Cover ing, Frost-Proof Pipe Covering. ACOUSTICAL--Ehret's sound ab sorption and isolation felts. 85% MAGNESIA Ehret's 85% Magnesia, in pipe covering, block and plastic forms, has become, during the past 40 years, renowned in every industry where insulating problems arise. It is pre-eminently suited for all temperature conditions up to 600F. Made from basic, hydrated, magnesium carbonate, the material which engineers agree is unsurpassed for heat insulating purposes due to its myriads of dead en trapped air cells. Magnesia is manufactured from dolo mite rock, mixed with asbestos fibre binder and moulded with a controlled pressure to insure proper strength without destroying the minute air cells. 85% Magnesia cover ing can be salvaged, if necessary, and ground up into cement. It is light weight and although it can absorb many times its own weight in water, it will dry out in service without impairing its efficiency. For out door use 85% Magnesia is furnished with an asphalt saturated asbestos felt jacket. Substitutions for 85% Magnesia in sulations are very expensive. Its high thermal efficiency and long life free from shrinkage and deterioration make 85% Magnesia the most economical. No. 18 INSULATING CEMENT A plastic having great adhesive pro perty, it sticks firmly to any surface. No wire or mesh supports being necessary, the application is easy and economical. Recommended for monolithic insulation. Highly efficient. Low in cost due to its large covering capacity. Is effective up to 1800F. HAIR FELT Ehret's Standard Hair Felt, manu factured by the Platen Process, is com posed of 100% pure cattle hair. Most efficient on temperatures from 100F above to 60F below zero; Its efficiency, particularly at sub zero temperatures, is due to the close felting of the hair, exclud ing moisture-laden air which might greatly harm other types from resultant con densation. Ideally suited for insulating tanks, refrigerator cars, steel passenger and tank cars. Usually applied in layers, each of which is thoroughly air sealed. . For brine and ammonia work, we recom mend a special "built-up" type of Hair Felt, fully described in our catalog "A-26." Punched Felts are also fur nished for special conditions. ENDURO HIGH TEMPERATURE INSULATION For those having problems with insulation at tetjiperatures from 600F to 2000F,, Enduro will prove of special interest. Information on request. Recommended Insulation Thickness for Flat Surfaces .Thermal Conductivities in Btu's Temperature of Hot Surface Under 300 300 to 450 450 to 600 600 to 700 Enduro.................. 85% Magnesia... Total...................... 1/2 m i'/i 3 i'/i 3 IV? 2 3'/2 700 to 800 2 2 4 Mean Temp. too 200 300 500 800 1000 85% . Magnesia 0.420 0.460 0.510 0.590 Enduro 0.465 0.500 0.550 0.620 0.730 0.840 (Plus a M in. Finish.) HEAT SEAL HOME INSULATION Loose Wool--Granulated Wool--Wool Bats No. 18 Cement 0.520 0.560 0.610 0.700 0.840 0.930 946 Insulation International Fibre Board Limited Sales Offices OTTAWA--MONTREAL--TORONTO--WINNIPEG Administrative Offices and Mills: GATINEAU, QUE. London Office THE TENTEST FIBRE BOARD CO. Ltd. Astok Housb, Aldwych, London, W. C. 2.. Encland ' TEN/TEST is a manufactured lumber made from spruce fibres, solidly pressed under hydraulic pressure into a strong, homogeneous board. The fibres are chemi cally treated and water-proofed during process of manufacture, until the insula tion is non-hygroscopic, free from capillary attraction and moisture-resisting in service commensurate with the maximum degree of insulation obtainable. Official Tests Conductivity. TEN/TEST has a con ductivity of 0.33 B.T.U. per hour per square foot per degree fahr. per 1 in. thick. Authority: Professor E. A. Allcut, M. Sc. M. I. Mech. E. Mem. A.S.M.E. Professor of Applied Mechanics, University of Toronto. Tests performed by Hot-Plate method. Mean temperature 47.8 deg. Tensile Strength 228 lb. per sq. in. Tests made on in. board cut to strips 1 in. wide and tested in a Riehle Tensue Testing Machine, the grips being 2 in. apart. 228 lb. is the mean average of seven series of tests. Transverse Strength (equal deflec tion) is 28.4 lb. Test made on %6 in. board, 6 in. wide, 18 in. long, on 12 in. centers, and load being applied to breaking point. Plaster Bonding Strength 2163 lb. per sq. ft. Brown and scratch piaster coats were applied to standard jfs in. board, and the pull registered in an Olsen Testing Machine. Authority: Columbia University Testing Laboratories, New York. . Moisture Resisting. TEN/TEST, after complete .immersion, in water for 24 hours, registered 37.5% increase in weight; Note.--Authority for tensile strength, transverse and moisture tests; J. T. Donald & Co., Ltd., Chemical Analysts and Engineers, Montreal, Que. TEN/TEST Products TEN/TEST Insulating Building Board. Standard insulation for use as exterior sheathing, interior finish; between walls and under floors for sound deadening. Standard Industrial Insulation for refrig eration and the prevention of condensa tion. Manufactured in convenient sizes: 4 ft. wide and up to 17 ft. long, % in. to 2 in. thick. TEN/TEST Notch Board Plaster Base. Insulating plaster base having tongue and groove interlocking joints. Provides an effective bond with plaster without use of metal lath at joints. Sizes: 16 in. wide; 32 in. and 47% in. long. Thicknesses from % in. to 2 in. TEN/TEST Roof Board. An effective roof insulation. Manufactured in two sizes: 1 x 4 ft. and 2 x 4 ft. Thicknesses from % in. to 2 in. ' TEN/TEST Ashlar Block (Acousti "A"). For interior decoration and acoustical correction. Absorbs 35 per cent of incident sound at a frequency of 512. Can be supplied in a variety of designs and sizes to harmonize with any decorative treatment, allowing the archi tect much freedom in design and finish of churches, auditoriums, theatres, etc. Ashlar Blocks have bevelled edges, standard or to suit, can be left in the natural color or tinted as desired. TEN/TEST Mouldings. An effective trim and finish for joints, corners, etc. Available in widths of % in. to 10 in. and lengths up to 12 ft. - TEN/TEST Moulding Edge Wall Panels. Conceals joints and provides excellent decorative treatment. Featured in widths 11 in. to 47% in., lengths up to 12 ft. HYDRO/TEST. Water proof, insula ting building board, designed particularly for low temperature requirements. Insulation The Insulite Company Executive Offices: Minneapolis, Minnesota Factories: International Falls Minnesota Kymi. Finland INSULITE Stocked by Dealers In All Principal Cities Throughout The World INSULITE BUILDING BOARD Insulite, the original wood fiber in sulating board, has been specified by engi neers and architects for 22 years--used for exterior sheathing or interior finish, duct lining, and other sound control work. Now available with two surface textures; fine screen and burlap, and in two' colors; standard light color and Graylite. Standard Building Board -- This board is of a natural light color with high light-reflecting value. Thermal con ductivity: 0.33 Btu/square foot/ inch/ hour/F, based on a density of 16 lb cubic foot. Thicknesses: Y in., % in., 1 in.; sizes up to 4 ft x 12 ft. Fine Screen Burlap Graylite Building Board--Graylite is made from the same wood fibers as the standard board, but during the manu facturing process each fiber is covered with an asphalt emulsion, slightly increasing the density of the board, and greatly adding to its tensile strength and moistureresisting qualities. Thermal conductivity: 0.35 Btu/square foot/inch/hour/F. _ The Patented "Lok-Joint" INSULITE LOK-JOINT LATH An insulating plaster base, with a pat ented "Lok" that firmly locks the sheets of Insulite together between supporting members, thus providing a rigid, level base for the plaster and insuring an adequate thickness of plaster. Fabricated from standard Insulite into units 18 in. x 48 in., shiplapped long edges. Thicknesses: Yi in., % in., 1 in. INSULITE TILE AND PLANK Insulite Tile and Plank used on walls and ceilings, create attractive interiors for all types of buildings. They provide thermal insulation, and reduce the rever beration of sound. Fabricated from Standard light colored Building Board and Graylite Building Board with, their re spective thermal conductivities. Tile--Insulite Tile, supplied in various sizes, is beveled on all edges; available with three types of joints; B-B, V-W, V-Lap; the latter two being inter locking, and the first two reversible, making it possible to com bine surface textures. Standard material fur nished in three surface textures; fine screen, burlap and smooth, and Graylite in burlap and fine screen only. Plank--Random width Insulite Plank, in lengths up to 12 ft, can be applied either horizontally or verti cally. The beveled long edges with B-B and V-W reversible joints, the latter inter locking, may be had either with or without bead. Supplied with two surface textures; burlap and fine screen in both the standard light color and the Graylite. 948 The Insulite Company Insulation INSULITE ROOF INSULATION Insulite Roof Insulation is made from the same wood fiber as standard Insulite. It can be used over any roof construction. The standard size is 24 in. x 48 in., for convenient handling, and with either offset or square edges. Furnished in thick nesses of lA in., 1 in., 1A in., and 2 in. Conductivity 0.32 Btu/square foot/inch/ hour/F. Asphalted Roof Insulation Insulite Asphalted Roof Insulation is a new and improved product, exclusive with Insulite. Treated with an asphalt emul sion during the process of manufacture, it provides those qualities of greater resis tance to moisture and greater durability so desirable in roof insulation, combined with an ideal base for bonding to the roof deck and to the roofing. Furnished in full Y in. thickness and in multiples of Yi in. up to 2 in. Size: 24 in. x 48 in. INSULITE HARDBOARD PRODUCTS Tough, durable grainless boards with hard, smooth, surfaces in various densities, and sizes up to 4 ft x 12 ft. DualBoard--Y in. thick; golden oak brown; has lowest density of all HardBoard products. DeLuxe DualBoard--% in. thick with smoother surface and greater density than . DualBoard. , HardBoard--Yo in., Yt in., Ye in., Y in., Ye <., golden oak color; much greater density than DualBoard. Tempered HardBoard--Same thick - nesses as HardBoard; burl walnut color; extremely high density. PanelTile--Same as Tempered Hard Board except that it is scored in 4 in. ^squares to simulate tile. INSULITE Applying Insulite Roof Insulation INSULITE SEALDSLAB Fabricated from special low density board, each block of Sealdslab is "sealed dry" with a %2 in. impregnation of a specially developed asphalt which insures an effective seal against moisture absorp tion after Sealdslab is asphalt coated or dipped during application on the job. The factory primed surfaces also insure an excellent bond for subsequent asphalt coatings. Available in same sizes and thicknesses as the standard Cold Storage Insulation. Sealdslab is especially adapted for use in freezers; meat, beer and creamery coolers; milk cooling tanks; fruit and vege table storage rooms and general cold storage rooms. INSULITE FIBEROCK Insulite Fiberock insulation is a rock wool product, treated for moisture resis tance, with low percentage of shot and with sufficient resiliency to prevent it from settling. Conductivity: 0.26 Btu/square foot/inch/hour/F. Available in three forms: Loose Fiberock--A fluffed form of rock wool insulation for hand packing in walls. Furnished in 35 lb bags, enough material to cover 15 sq ft surface area, wall-thick. COLD STORAGE INSULATION Cojd Storage Insulation is a low density Insulite product which has found a wide acceptance for use in refrigerator cabinets, refrigerator cars, ice houses, storage plants, breweries, and other places where low temperatures are maintained. The ther mal conductivity is 0.29 Btu/square foot/ indj/hour/'F and is available in eleven standard sizes and in thicknesses of 1 in., . \Y in., 2 in., 3 in., and 4 in. Granulated Fiberock--A granular form of rock wool which can be con veniently poured into place. Usually used over ceilings. Also supplied in 35 lb bags, enough to cover .13 sq ft surface area, 3% in. thick. Fiberock Bats--Rock wool in bats 15 in. x 23 in. to fit snugly between studs and joists. ; The bats are wall thick and require no special fastening. Packed in Cartons of 9 bats each. , 949 Insulation Johns-Manville Executive Offices 22 East 40th Street, New York, N. Y. Offices in All Large Cities ----- US!-----MiraMtunnui Johns-Manville Home Insulation J-M Home Insulation involves the ap plication of J-M Rock Wool (actual rock fibre) within the walls and the roof or attic spaces of residences, stores, apartment buildings and other structures. J-M Home Insulation is thick insula tion, remarkably effective in providing year round comfort and in reducing fuel bills. (On hot summer days homes in sulated with this material are up to 15 cooler; in winter fuel bills are reduced up to 40%). J-M Home Insulation is non combustible, sanitary and odorless, and will not support vermin. Furnished in two forms: Type A for blowing into existing construction; and Type B bats for new homes. Blown Method---Type A In the Type A form, Rock Wool is blown by air into the spaces between studs in outer walls and between rafters or joists in attic floors. The insulation thickness in the walls corresponds to stud depth, approximately in., and the density does not exceed 10 lb. per cubic foot. J-M Home Insulation has been installed by this method in thousands of existing homes. This type of material is installed by J-M Approved Home Insulation Contractors, who are equipped with the necessary apparatus. A pplying J-M Home Insulation bats in new home Bat Method--Type B Home Insulation Type B is furnished in resilient bats, 15 in. by 18 in., or 15 in. by 23 in., full stud thickness. This form is widely,used for homes or buildings under construction. The bats can be readily pressed between studs or beams and" are easily cut or torn to fit odd-shaped spaces, conforming perfectly to the space occupied and providing a continuous insulation of even density. . Data and Specifications For technical data and specifications onboth types of J-M Home Insulation, write for brochure HI-17A. J-M Insulating Board and Plaster Lath J-M Insulating Board is a light weight, efficient material, having high insulating value and moisture resistance and unusual structural strength and rigidity. Furnished 4 ft. wide, in lengths up to 12 ft. Thick nesses ]/2, % and 1 in. ' J-M Insulating Lath is the same material as Insulating Board, except that it is fur nished 18 in. by 48 in. with long edges ship- lapped and all edges beveled. The ma terial is furnished in thicknesses of Vi, M and 1 in. ~ 950 Johns-Maneille Insulation Johns-Manville Pipe and Boiler Insulation on either hot or cold water service piping. By the use of waterproofed felts shrinkage . troubles have been minimized. Supplied in two finishes, the regular canvas and a smooth, dull-coated alumi num. In either finish, it is furnished in 3-ft. sections in thicknesses of in. % in., 1 in.. Double in., and Double % in., for pipe sizes from in. to 5 in. J-M Pre-Shrunk Asbestocet Pipe Insulation J-M Pre-Shrunk Asbestocel Pipe Insulation J-M Pre-Shrunk Asbestocel is a radically improved material in which, by the use of waterproofed asbestos paper, shrinkage troubles have been minimized. It is used for hot water or low pressure steam piping, including supply and return mains, branches and risers. Supplied in three finishes: The regular canvas finish; and the new high-speed asbestos paper or aluminum finished material which clinches on tight with quick-fastening staples. All types are furnished in 3-ft. sections in standard thicknesses of 2, 3, and 4 plies, each ply approximately in. thick. J-M 85% Magnesia Recommended as the most efficient injsulation of the molded type for tempera tures up to 600 F. Pipe insulation is furnished in sectional or segmental form for all commercial pipe sizes, in thick nesses up to 3 in. Blocks are 3 in. by 18 in. and 6 in. by 36 in., flat or curved, from in. to 4 in. thick. i. J-M Pre-Shrunk Wool Felt Due to its Dual-Service Liner--an. asphalt-saturated felt--J-M Pre-Shrunk Wool Felt is equally effective and durable J-M Asbesto-Sponge Felted . Recommended on all high pressure steam piping at temperatures up to 700 F. where insulation may be subjected to rough usage or where maximum efficiency and durability are desired. Furnished in 3-ft. sections up to 3 in. thick. J-M Superex Combination Superex Combination Insulation (an inner layer of high temperature Superex and an outer layer of 85% Magnesia) is recommended where temperatures exceed 600 F. Superex and Magnesia are both furnished in sectional and block forms. J-M Pre-Shrunk Asbestocel Sheets Asbestocel Sheets are used for insulating warm-air ducts, flues, heater casings and fan housings in the ventilating system. Temperature limit 300 F. Furnished 6, 9, 12, 18 and 36 in. wide by 36 and 72 in. long, from in. to 4 in. thick. J-M Rock Cork J-M Rock Cork is made of rock wool and a moisture-proof binding ingredient molded into sheets for insulating refrigerated rooms and air conditioning ducts. It is strong, durable, and will not support vermin. Because of its unusual moisture resistance, its high insulating efficiency is maintained indefinitely. Furnished 18 in. by 36 in., in 12, 3 and 4 in. thicknesses. Also 18 in. by 18 in. by 1 in. thick. Detailed Specifications Specifications for the use of any J-M Insulating Material may be had on request. Insulation Mundet Cork Corp. 450 Seventh Avenue New York, N. Y. Manufacturers of Corkboard, Cork Pipe Covering, Compressed Machinery Isolation Cork, Natural Cork Isolation Mats, Cork Tile, Cork Bulletin Board, and all kinds and varieties of Cork Specialties. Branches Atlanta, Ga. Boston, Mass. Buffalo, N. Y. Chicago, III. Cincinnati, Ohio Dallas, Texas Detroit, Mich Houston, Texas Kansas Crrr, Mo. Los Angeles, Calif. Memphis, Tenn New Orleans, La. Philadelphia, Pa. St. Louis, Mo. San Francisco, Calif Agents Baltimore, Md.,,...................... The McCormick Asbestos Co. Charlotte, N. C________________________C. R. Howard Cleveland, Ohio____ ____ _________ _______________ C. S. Ross " _______ a, V"a...,, -Fredericksburg Insulation Co. Hartford, Conn_______ ..... The Hartford Cement Co. Nashville, Tenn________ ___ John Bouchard & Sons Co. Oklahoma Citt, Okla__ Standard Roofing & Material Co. Portland, Oregon___________ ~.r -------------- F. J. Leonard Portland, Oregon_________ Pacific Asbestos & Supply Co. Salt T arts Crrr, Utah_____ __________________Louis A. Roser Seattle, Wash.______ _________ Pioneer Sand & Gravel Co. Tulsa, Pel*-____________ .Standard Roofing & Material Co. Utica., N. Y.___ -Georg_e Weisenberger Washington, D. C---------Asbestos Covering & Roofing ( Engineering and Specification Service Our engineering department is at the service of Architects and Engineers at all times to assist and advise in the prepara tion of specifications pertaining to cork. This service is also available to any one who has a cold insulation or a vibration isolation problem, and is rendered without obligation. Our complete catalogue is filed in Sweet's Architectural Catalogue, and will be sent on request. It is replete with valuable information and data that should always be within reach of every specification writer whose field touches our products. Contract Service We contract for the erection of our products. In this way we may be certain that our material is installed in accordance with best established practice. This gives a definite advantage to an owner, in that divided responsibility for a given instal lation is eliminated. No contract in volving cork is too large, too small or too far away. All materials and workmanship are unqualifiedly guaranteed. manufactured make it suitable for pipes carrying sub-zero to 50 F. temperature. The pipe covering comes in sections 36 in., long. A complete line of standard fitting covers is available in the three thick nesses. Mundet Cork Vibration Isolation The transmission of machine vibration can be easily and permanently prevented by the use of Mundet cork isolation. The machines commonly associated with the heating and ventilating industry are best isolated with Mundet Natural Cork Isolation Mat. This form of isolation is fabricated from blocks of pure cork. These blocks are held together within a rigid steel frame or bound with asphalt paper applied with hot asphalt top and bottom. Steel bound isolation mat is Mundet "Jointite" Corkboard Mundet "Jointite" Corkboard is 100 per cent pure cork, fabricated in accor dance with the U. S. Government Master Specification, and is unsurpassed in its field. It is used for all cold insulation services and for acoustical correction. We manufacture only one grade of corkboard. Mundet "Jointite" Corkboard is sold in the standard 12 in. x 36 in. sheet. Stand ard thicknesses are in., 1 in., 1J3 in., 2 in., 3 in., 4 in. and 6 in. Mundet "Jointite" Cork Pipe 1 Covering Mundet "Jointite" Cork Pipe Covering is the complement of Mundet "Jointite" Corkboard and is used for all types of cold lines. The three thicknesses in which it is AboK is shown a Stool Bound Mundet Natural Cork Isolation Mat; Note the natural cork strips within the steel frame. usually used under exposed mounts, and asphalt paper bound isolation mat, under concrete foundations, of the envelope type. Mats are constructed to fit under any type of machine foundation. . For loads exceeding 2,000 lb per square foot, we manufacture Mundet Machinery Isolation Cork, which is a board form of compressed granulated cork and comes in. three densities. .. Both types of isolation are furnished? in 1 in., lj'i in., 2 in., 3 in.,'4 in. and.6 in. thicknesses, depending on the class of service. ______________ _______ Silvercote Products, Inc. 161 E. Erie Street, Chicago, 111. Insulation SILVERCOTE INSULATION Fabric--Manufactured from two ex ternal sheets coated with a mineral pig ment and polished to a highly reflective surface possessing the essential character istics hereinafter described- for all Silver cote surfaces. The sheets are laminated with specially prepared asphaltum and reinforced with an interlining. of fabric, imbedded in the lamination, consisting of mesh of strong jute cords. Two silver like surfaces are exposed. The material is strong, flexible; and*can be creased, folded, and tucked into the most inaccessible places without injury. Weight: 80 lb. per 1000 sq. ft. ' 3. The surfaces are highly moisture resist ant, equal in this respect to sheet lead. 4. The surfaces are not affected by acids or gases encountered in the customary . uses of thermal insulation, whether in building construction, refrigeration or the cold storage fields. 5. The surfaces are entirely homogeneous and impervious to air infiltration wherever used. 6. The surfaces are non-conductors of electric and thermal energy and are designed to establish a difference in surface temperatures on transverse sur faces in the direction of heat flow. Coreboard--Laminated of 7-plies of pulp board. 16 point liners coated on the exposed sides and polished to highly reflective surfaces. Finished board is % in. thick with 2 silver-like surfaces exposed. Weight: 1000 lb. per 1000 sq. ft. Insulation Board--Manufactured in a manner similar to wood fibre wallboard, to which is applied a top liner coated with pigment and polished to a highly reflective surface. Reverse side has a manila liner, dead level, beater sized and tacky; a per fect surface for painting. Finished board is 2^6 in. thick. Weight: 550 lb. per 1000 sq. ft. Silvercote Insulation Fabric-Conductance. 0.33 = Resistance 3.03 Silvercote Insulation Board-Conductance. 0.49 = Resistance 2.04 Silvercote Insulation CoreboardConductance 0.265 = Resistance 3.77 For complete specifications and technical data see Sweet's Catalog, or address Silvercote Products, Inc., 161 East Erie Street, Chicago, 111. SILVERCOTE SURFACES The surfaces of all Silvercote products consists of a non-metallic, homogeneous pigment, polished into a silver-like sheen which reflects radiant heat to a marked degree. They possess the following essential properties: 1. The surfaces are not metallic and are consequently free from oxidation to which all metal surfaces (except gold .and platinum) are subject. 2. The surfaces are waterproof. 953 Insulation Reynolds Corporation Executive offices: 19 Rector Street, New York City Western Sales Representative 400 Wrigley Building Chicago, 111. Pacific Coast Sales Representative 345 Ninth Street San Francisco, Calif. REYNOLDS METALLATION* Metallation* is bright, polished, genuine sheet aluminum, cemented to'one or both sides of heavy, tough kraft paper. Prop erly installed, it serves as effective heat insulation for dwellings and buildings, re ducing heat losses through walls and roof during winter, and maintaining more com fortable conditions in hot weather. Metallation because of its light weight, has negligible heat storage capacity. In summer very little heat is stored in the insulation, to be released into the rooms after sundown and in winter very little heat is absorbed from within the room. Buildings which are intermittently heated or cooled can be heated or cooled quickly and economically. Type A--Genuine sheet aluminum ce mented to both sides of heavy, tough kraft paper with 1)4 in. plain paper margins exposed. Type A is especially designed and scored for installation between studs, joists or rafters, with paper edges nailed inside framing members to form a curtain of insulation between two dead-air spaces. Type B--Genuine sheet aluminum ce mented to both sides of heavy, tough kraft paper. Type B is especially designed for application horizontally or vertically over studs, rafters or joists, in a way that provides an air space on each side of the Metallation. Type C--Genuine sheet aluminum ce mented to one side of heavy, tough kraft paper. Type C is especially designed for use as building paper, under sheathing or roof boards and in types of construction in^ which only one surface can face an air space. Type width of Roll Length of Roll Weight of Roll Area of Roll A 17 in I75ft5tn 181b 250 sq ft B 32 in 93 ft 9 in 161b 250 sq ft B 25 in 120 ft 161b 250sqft C 32 in 93 ft 9 in 131b 250 sq ft Metallation, Metallated Ecod and Ecod are trade-marks of Reynolds Corporation, duly registered in the U. S. Pat. Off. See SWEETS Architectural Catalog for complete details or write the nearest Reynolds Corporation sates office. Metal lation is sold by leading lumber and build ing material dealers throughout the U. S. Used by U. S. Government, leading archi tects and engineers. ADVANTAGES OF METALLATION High, lasting, insulating efficiency which remains unimpaired by moisture absorp tion. Non-corrosive. Low weight and bulk. Wind-proof, vermin-proof and odor less. Low cost. Easy to apply. Saves fuel; reduces heating and air-conditioning requirements. NOTES FOR HEAT TRANSFERENCE TABLE on opposite page "Computed by standard methods from data in American Society or Heating and Ventilating Engineers Guide, Vo!. 12 pp. 71-92, 1934, and from "Thermal Insulation of Buildings," American Architect, May, 1934, pp. 89-100 bOutside film resistances (/o) are based on a IS mph wind velocity; inside film resistances (/i) are based on still air. cAll air spaces are at least % in. wide. ' dThe thicknesses of 1 in. yellow pine sheathing and Scoring is approximately % in. ePlaster 54 in. to M in. thick is applied to ECOD or expaned metal plaster rase.' fWal! insulated as in Column IV with added 1 in. air space between brick and sheathing faced with Type C Metallation on outside of sheathing. ^ \ sFour inches of face brick and four inches of common brick. hCurtain of either Type A or Type B Metallation in furred space, having one side faring masonry and the other' side facing Type C or ECOD Met&U&tion. The thickness of oak flooring is approximately % in- iType A of Type B Metallation is so applied to joists or rafters', or flanged between them as to form an air space. One side of the Metallation faces the building material and the other side faces still air. kTvpe A or Type B Metallation is so applied to joists or flanged between them as to form an air space. One aide of Metallation faces Type C or ECOD Metallation, the other faces still air. - ISpace insulated as in Column IV except that Metal lation nearest still air is Type A or Type B. ' mNailing strips measure approximately *$6 by 354 in* and are spaced 2 in. apart. - nType A or Type B Metallation is applied between rafters and nailing strips to form one air space facing Metal lation'and a series of small air spaces faring shingles. -N, oRoof insulated as in Column IV except that Type A or Type B Metallation is applied as in Note N pType A or Type B Metallation is. applied between . nailing strips and rafters and also to under side of rafters; qType A or Type B Metallation is applied as in Note P and also as a central sheet parallel with the roof. Reynolds Corporation Insulation PERCENTAGE OF HEAT TRANSFER STOPPED BY REYNOLDS METALLATION* Coefficients (U) are expressed in Btu per hour per square foot per degree Fahrenheit difference In temperature between the air on the two sides of the construction. Columns (%) show the percentage of heat which REYNOLDS METALLATION stops from flowing through the respective constructions. n on opposite sides w ith Type b _Eo ILLUSTRATION a Z CONSTRUCTION I c .2 <9 o |h n W8*3v*2 3 D*Ss U V c Q. s Type C or Ecod M etallation on both sides o f air II III c8 S i t Type A or Type B M etalla tion form ing curtain be tween tw o a ir spaces. (Except where noted) Type A or Type B Metal lation form ing curtain be tween tw o a ir spaces, faced IV FRAME OR VENEER WALL Shingles or Clapboards, Sheathing.d Stud Space.c Plaster.e Drop Siding, np Sheathing. Stud Space, Plaster Mn. Stucco with Ecod Base. Stud Space. Plaster 1-ln. Stucco with Ecod Base. Sheathing. Stud Space. Plaster 4-In. Face Brick Veneer, Sheathing. Stud Space, Plaster MASONRY WALL 8-In. Solid Brick.8 Furred Space. Plaster 4-ln. Face Bride on 8-ln. Hollow Clay Tile. Furred Space. Plaster 1-In. Stucco on 12-In. Hollow Clay Tile. Furred Space. Plaster 12-In. Hollow Concrete Blocks. . Furred Space. Plaster FRAME MIDDLE STORY FLOOR Single Yellow Pine Floor,d Joist Space. Plaster Oak Floor,* Yellow Pine Sub-Floor, Joist Space. Plaster FRAME ATTIC FLOOR No IHoor, Joist Space, Plaster Single Yellow Pine Floor. ' Joist Space. Plaster FRAME FIRST STORY FLOOR 14 Single Yellow Pine Floor, Joist Space, no Ceiling 15 Oak Floor, Yellow Pine Sub-Floor, Joist Space, no Ceiling MASONRY FLOOR-SUSPENDED CEILINC 16 4-In. Reinforced Concrete. Furred Space. Plaster * 17 6-In. Reinforced Concrete. Furred Space, Plaster 18 4-In. Concrete, 4-In. Hollow Tile. Furred Space, Plaster 19 4-In. Concrete, Mn. Hollow Tile, Furred Space, Plaster FRAME ROOF 20 Wood Shingles. Nailing Strips,na 21 Rafter Space. Plaster Wood Shingles, Nailing Strips, Rafter Space, no CeUing 22 Composition or Asphalt Shingles, Nailing Strips, Rafter Space. Plaster 23 Composition or Asphalt Shingles, . Nailing Strips, Rafter Space, no Ceiling , FRAME ROOF 24 Wood Shingles, Sheathing. Rafter Space, Plaster 25 Wood Shingles, Sheathing, Rafter Space, no Ceiling ' 26 Slate or Cement Shingles, Sheathing. Rafter Space. Plaster ' 27 Slate or Cement Shingles, Sheathing. - Rafter Space, no Ceiling U% .26 0 .37 0 .50 0 .33 0 .30 0 .32 0 .25 0 .22 0 .32 0 .30 0 .25 0 .69 0 .30 0 .46 0 .35 0 .37 0 .35 0 .27 0 .23 0 .30 0 .46 0 .37 0 .64 0 .27 0 .40 0 .34 0 .56 0 u% .19 27 .25 32 .31 38 .24 27 .22 27 .23 28 .19 24 .17 23 .23 28 .22 27 .19 24 .26(0 62 .22 27 .22(052 .19(046 .25 32 .24 31 .20 26 .18 22 .22 27 .22(052 .25 32 .25(061 .20 26 .20(050 .24 29 .24(0 57 U% .18 31 .24 35 .28 44 .22 33 .21 30 .21 30 .18 28 .24(k)65 .21 30 .2l(k)54 . I8(k)49 .I8(n)40 .I8(p)6l . 20( n>46 20(p)69 .19 30 . 19(k)53 .22 35 .22(k)61 U% .14 46 .16 57 .18 64 .16 56 ' 15 50 .15 53 .13 48 .13 41 .15 53 .15 50 .13 48 .26(062 .15 50 .22(052 .19(046 .16 57 .16 54.14 48 .13 43 .15 50 .22(0 52 .16 57 .25(061 .14 48 .20(050 .16 53 24(j)57 U% .13 50 .15 59 .17 66 .14 58 .11 (f) 63 .15 (h> 53 .13 (b) 48 .12 (h) 46 . .15 (h) 53 .14 53 .13 ' 48 .15 (l) 78 .14 : 53 .14 fl) 70 .12 0) 66 .16 (h) 57 .15 (h) 57 .14 (h) 43 .12 (h) 48 .12 (o) 60 .12 (q) 74 .13 (oj 65 .14 (q) 78 .13 52 .13 (1) 68 .14 59 .14 0) 75 955 (CExo rceEptcowdherMee tallatio noted) Insulation . New York The Ruberoid Co. Executive Offices 500 Fifth Avenue, New York, N. Y. Chicago Divisional Offices Boston (Millis) Erie Baltimore Mobile RUBEROID RESIDENTIAL INSULATING PRODUCTS Genuine RU-BER-OID Mineral Wool From the viewpoint of efficiency, Mineral Wool is one of the finest insulating materials for residential construction. It can be used in varying thicknesses up to 4 in. It cannot deteriorate or decompose, and is fire- and vermin-proof. This in sulation can be expected to save 20 to 35 per cent in fuel bills in the winter, and make the interior of the home 10 to 15 deg cooler in summer. Genuine RU-BER-OID Mineral Wool in the loose or bulk form is clean, silky and long fibred, a quality which overcomes the tendency to pack and settle. It is free from harsh brittle particles. This wool is offered in three forms--loose or bulk for packing, granulated for pouring, and in pre-formed bats for use between joists, rafters, and studding. Loose Mineral Wool The loose mineral wool is packed in 35 lb bags containing about 3H cu ft. A bag will cover in excess of 21 sq ft gross (in eluding the studs or joists) V/% in. thick when packed to a service density of 6 lb per cubic foot'. ' . The long silky fibres make this wool extremely' stable, overcoming the tendency to Pack and settle Granulated Mineral Wool Granulated Mineral Wool is in pellet form averaging from the size of a pea to a marble. In this form it is easily poured between studs and joists and for filling in irregular spaces. Bags contain 40 lb. When applied to a- service insulation density of about 7 lb per cubic foot, 4 in. thick, it gives a coverage of about 17 sq ft per bag. Mineral Wool Bats ,. Mineral Wool Bats are packed in cartons containing 9 pieces, 15 sq ft. The bats are wall thickness (approx. 4 in.) measuring 15 in. x 18 in. which permits easy application between the studding of side walls, or between the rafters under the roof. ' RUBEROID INDUSTRIAL INSULATING PRODUCTS 85 Per Cent Magnesia for Medium and High Pressure.Steam Lines 85 per cent Magnesia pipe coverings are made of approximately 85 per cent pure carbonate of magnesia and 15 per cent carded long Asbestos fibre. Temperature limit 600 F. Light in weight, fire-proof, extremely high insulating value, yet have maximum mechanical strength consistent with efficient insulation. Supplied in various thicknesses up to 3 in., canvas jacketed. For Higher Temperatures . .. MINERAL WOOL BLANKETS Limit 1800 F . Mineral Wool for flat or curved surfaces is manufactured into blankets by using' annealed long fibre wool, felting it arid : building it up to the required thickness 956 The Ruberoid Co. Insulation Supercell Pipe Covering has 14 to 16 laminations of indented Asbestos Felt to the inch between metal fabrics of various types. | These blankets are secured with gal vanized wire between the metal fabrics. Watco Cell Limit 500 F Thickness from 1 in. to 6 in. Standard Close corrugation, 6 and 8 ply to the size blankets 24 in. x 96 in. and 24 in. inch, raises efficiency standards. Either x 48 in. new Pyroxylin finish or canvas jacketed, as desired. Temperature limit 500 F. High Temperature Pipe Coverings Limit 1600 F This insulation is recommended for in sulating surfaces having temperatures be tween 600 F and 1600 F. It has low thermal conductivity, practically no shrink age, is light in weight, and has good mechanical strength. Supercell Pipe Covering for Low and Medium Pressure Steam Lines Limit 500 F Woolfelt - For Hot and Cold Water Lines Special surfacing process increases .ef ficiency 20 per cent to 30 per cent. Weight also is reduced 20 per cent to 30 per cent. Made in three styles of liners: Asbestos Felt Paper for hot water lines; Water proofed Tar for cold water lines; "Twin Purpose" for both hot and, cold water lines. Furnished in either the new Pyro xylin finish or with canvas jacket. ... . Sheet and Block Insulations . Supercell Pipe Insulation--A new development in the low and medium pres sure field, has a temperature limit of 500 F. It has 14 to 16 laminations of indented Asbestos Felt to the inch thickness. It is considerably lighter than the old-fashioned pipe insulation, yet, due to its unique con struction, provides as much as 35 per cent higher efficiency. Other Insulating Materials for Low and Medium Temperature Steam Lines--Air Cell--Limit 350 F ..Made 2, 3 and 4 ply--each ply % in. thick. Furnished in either the new Pyroxylin finish or with canvas jacket. Temperature limit 350 F. Ideal for in dustrial hot water lines. Any of the pipe coverings can be made into sheet and block form; Standard sizes 6,12,18 or 36 in. x 36 in. Ideal for insula tion of flat or irregular surfaces, such as tanks, boilers, breechings, etc. Insulating Cements For the finishing of asbestos sheet and block insulation, or the insulation of valves, fittings, or flanges, or any sort of irregular surfaces, the line of RuberoidWatson Insulating Cements is quite com plete. Will take care of temperature con ditions from 100 to 2000 deg F. Detailed Specifications Complete catalog giving specification data of any Ruberoid Insulating Product may be had upon request. . 957 Insulation The Standard Lime & Stone Company First National Bank Building, Baltimore, Md. Manufacturers of Capitol Rock Wool Insulations Representatives in all Principal Cities The Bat it readily inttalled where studding it open or in new construction The blowing method it uted in exitting houses between wallt or floors Home Insulation for year-round com- cooler than outside. Variation between fort is the demand of the home owner first and upper floors will be negligible: today, because a properly insulated home Capitol Rock Wool is also fire-proof, ver- saves fuel, resists fire, deadens sound, is min-proof, and water-resistant, cooler in summer and warmer in winter, In new construction it is easily installed and sells more easily. in compact, felted Bat form by the Capitol Rock Wool is the nearest ordinary workman. Weight: 6 lb. per approach to perfect insulation. In winter cubic foot. Thermal conductivity: 0.257 it provides even temperatures all over the BTU. In houses already built, whatever house, eliminates drafts, and reduces fuel the type of construction, Capitol Grade bills from 20 to 40 per cent. In summer, "A" Blowing Fibre is pneumatically con- the temperature inside will be 8 to 15 deg. veyed into the wall air spaces. INDUSTRIAL INSULATIONS Blankets--A reinforced felted Capitol Rock Wool designed primarily for insulating boiler settings, fire walls, boiler breechings, smoke stacks within buildings, tank cars, hot water heaters, boilers, oil stills, bubble towers, large diameter pipes, ducts, etc., and for absorbing sounds set up by machinery. Insulating Blocks--A compressed pliable product for temperatures up to 750 F., for insulating domestic furnaces, boilers, and hot water tanks; and for commercial^ boilers, tanks, ducts, stills, and breechings. Pipe Coverings--With canvas or waterproof cover for temperatures from 60 F. below zero to 1250 F. Insulating Cement--Plastic; quickly and neatly applied: available in both high and low temperature cements. n CATALOGS and Specifications of our complete line of home and industrial insulations gladly sent on request. . 958 Insulation United States Gypsum Company Atlanta, Ga. Boston, Mass. Buffalo, N. Y. Cincinnati, Ohio Cleveland, Ohio 300 W. Adams Street, Chicago, 111. Sales Offices: Dallas, Texas Denver, Colo. Detroit, Mich. Indianapolis, Ind. Kansas Cm, Mo. Los Angeles, Calif. Milwaukee, Wis. Minneapolis, Minn. New York, N. Y. Omaha, Neb. Philadelphia, Pa. Pittsburgh, Pa. St. Louis, Mo. San Francisco. Calif. Washington, D. C. PRODUCTS: Building Board. Insulating Mouldings. Tongue and Groove Sheathing. Insulating Lath. Metal Reinforced Insulating Lath. Roof Insulation. Insulating Tile Board. Insulating Tile. Insulating Plank. Bulk Wool. Strip Wool. Wool Bats. Granulated Wool. RED TOP WEATHERWOOD, LATH, PLANK, SHEATHING AND TILE Weatherwood Insulating Board is a felted wood fiber product'that has been treated to make it highly moisture re sistant. It is formed on a single cylinder which produces a homogeneous board, free from laminations and tendencies to split through the center. Low Thermal Conductivity . The average established in tests is 0.33 Btu's per hour, per square foot per inch thinkness, per degree Fahrenheit dif ference in temperature. Resistance to Moisture--Non Absorption Tests show that this board, after being submerged in water for a period of two (2) hours, has an average water absorption of less than 15 per cent. 'Structural Strength The tensile strength is over 350 lb per square inch, and the modulus of rupture, 5 over 500 lb. Durability There is nothing in this board that will deteriorate prematurely and impair the original insulation value. Since the board is homogeneous, the fibers being inter woven through the sheet, it will not split. The Moisture Resistant chemical with which the fibers are treated makes the board distinctly distasteful to rodents and insects. Uniformity Adequate laboratory control and mill inspection assure uniformity in density and structural strength. RED TOP INSULATING WOOL Description . Red Top' Insulating Wool is an ex tremely light, fluffy wool insulation made of silica--a fireproof material. The nature of the raw materials used, particularly as to purity, permits accurate manufacturing control--the product is absolutely uniform and consists of snowy white, long-fibre wool. It contains no "shot" or other non-insulating materials that add weight. Red Top Insulating Wool is springy and resilient--it will not mat. Low Thermal Conductivity ' The heat conductivity of Red Top Insulating Wool (1)4 lb density) is 0.266 Btu's per inch thickness, per square foot, per hour, per degree' Fahrenheit dif ference in inside and outside temperatures. (Tests by Professor Peebles, Armour Institute of Technology). Unusually high in insulating efficiency, it is outstanding when, as customarily used, it is wall thick (4 in.). So used its rating is 0.066. . Light Weight (Density) In its standard density, Red Top Insulating Wool weighs but 1)4 lb per cubic foot. Type of .Wool Strip'Wool in cartons Bat Wool in cartons Bulk Wool in paper bags COVERAGE OF RED TOP INSULATING WOOL Volume per package at standard density 1 W* cu ft 12*/2 cu ft (20 bats) cu ft Coverage per package at standard density 4 in. thick, including 2 x 4's 36 sq ft 40.sq ft . 20(/| sq ft 4 in. thick, excluding 2 x 4's 33*4 sq ft 37y2 Bq ft 19 sq ft Insulation Long Island City Zonolite Corporation General Offices Fisher Building, Detroit, Michigan Joliet, Illinois Plants At Omaha Detroit St. Louis Trade Mark Reg. U. S. Patent Office Libby, Montana THE PERFECT INSULATION ZONOLITE INSULATION FOR HOMES ZONOLITE LOOSE FILL Zonolite is a mineral which has been expanded many times by the application of intense heat. Each particle contains thousands of tiny dead air cells which make Zonolite a non-conductor of heat. And, in addition, every particle is filled with glittering, golden surfaces that make Zonolite a reflector of heat. Zonolite provides a natural DUAL insulation. Zonolite has a uniform, tamper-proof density. Its actual insulating value in the walls of a house is always the same as thetheoretical insulating value as shown by laboratory tests. Zonolite cannot be "fluffed" or stretched when being installed. It. flows naturally, filling every nook and comer. joists or rafters. When put between walls, Zonolite pours easily, requiring no ma chinery and taking a minimum of time and labor. Your local Zonolite representative will furnish accurate estimates of instal lation costs. Zonolite is packed in 33^ cu ft bags with the following coverage: ZONOLITE POURS EASILY Zonolite is easily installed in attics by^ pouring directly from the bag between 20 square feet.......... 2 in. thick 14 square feet.'.........3 in. thick 11 square feet._....... 3% in. thick AN EFFICIENT HEAT BARRIER One of the many tests of Zonolite's resistance to heat passage was made by the Consolidated Gas, Electric Light and Power Co. of Baltimore. A hot plate test showed a thermal conductivity rating of 0.27. In addition ".U" factor tests show its effectiveness as an insulating material. Zonolite is FIREPROOF--a 100 per cent mineral; VERMIN PROOF--rats or mice will not burrow or nest in it; termiteproof;-SOUND ABSORBING--tests by V. O.Knudsen, acoustical authority, show Zonolite to be high in sound absorption, and sound insulation:: 3% in. of loose Zonolite, in panels of 3 ft x 3 ft.6.in., showed a coefficient of sound absorption of 0.58 at a frequency of 512 d.v.; DIELEC TRIC--a test by J. C. Peebles, Armour Institute of Technology, showed that 20,800 volts were required to puncture a one-inch layer of Zonolite between oneinch brass balls; CHEMICALLY INERT --tests of every description prove that Zonolite will not. rot, rust, or deteriorate in any way. Zonolite forms a. THICK insulation; is approved by leading air con ditioning firms for use with their units. ZONOLITE INSULATING PLASTER A prepared mixture of carefully selected calcined gypsum and Zonolite. The growing interest in insulation is bringing this plaster into widespread use, as it provides an inexpensive insulation in cases where economic or construction difficulties render a complete insulating' job imprac- 960 Zonolite Corporation Insulation ticable. Tests made by J. C. Peebles of Armour Institute of Technology show heat conductivity of Zonolite Insulating Plaster, 0.90. Since it contains no sand, Zonolite Insulating Plaster is very light in weight-- Zonolite plaster weighs only 10 lb per yard on wall--thus it is extremely easy to handle and spreads rapidly. It is uniform, since it is not dependent upon varying grades of sand. It also possesses a high degree of sound-insulating value, and is free of map cracks. Zonolite Insulating Plaster, in a texture finish, is furnished in a wide variety of soft, attractive tints; Showing equipment used for extensive test's by the . Detroit Edison Co. . 1. Conventional-type Air Duct. S. Zonolite Air Duct. This adds another advantage to the list S. Zonolite Air Duct with Insulation Applied which includes comfort in winter and summer, fuel-saving, sound insulating, fire mesh rather than a solid strip of metal, and safety and ease of handling. is then covered with Zonolite fire-proof Air Duct Insulation, which has unusual insula ZONOLITE HIGH TEMPERATURE CEMENT Ideal for insulating tanks, boilers, furnaces, etc., where the insulation must withstand temperatures up to 2300 deg. It has a thermal conductivity factor of 0.46 at 100 deg, arid up to 1.9 at 2000 deg. ZONOLITE HIGH TEMPERATURE CEMENT BLOCKS are made for in dustrial oven insulation and have proved highly efficient. These blocks are made 1 ft x 3 ft with thicknesses varying from 1 in. up to 4 in. t ting and sound absorbing values and elimi nates the necessity for an inner lining. Tests by leading air conditioning firms show a reduction in noise of 113^ decibels. With the Zonolite patented type of duct, it is now possible to use a much smaller duct and higher air velocities, which make for more pleasing, practical, and economi cal home and building installations. Zonolite Patented Air Ducts are made exclusively by local sheet metal shops licensed by the Zonolite Corporation. ZONOLITE INSULATED ROOFING ZONOLITE COLD STORAGE INSULATION An unique combination gives a proper insulation and roofing material in. one Made of Zonolite and a moisture-proof binding element. It is in sheet form, for insulating refrigerated rooms. Sturdy, serviceable; does not support vermin. It is so resistent to moisture that its efficiency will continue indefinitely. Available iri sheets of all sizes; 1 to 4 in. in thickness. product. A combination of high grade asphalts and Zonolite is bonded together in such a way as to withstand great changes . in temperatures without cracking or softening. The latest practice is to use Zonolite roofing with two plies of felts over it. This construction is practically permanent as the product is 100 per cent mineral composition and can be installed ZONOLITE INSULATED AIR DUCTS . {Patents applied for--all infringements will be prosecuted) in any weather. In addition, if the roofing felts should ever crack, any entrance of moisture could not cause the product to deteriorate in any way, which makes the . Recognizing the insulation defects of the ordinary air duct, Zonolite engineers . decided to perfect the product as a whole rather than simply to engineer a new style of insulation for this type of work. In using the conventional type of sheet metal maintenance problem a very simple one; * nothing more than an occasional mop coat being needed to make the roof last in definitely. construction, the velocity of the air is j greatly reduced because of' the necessity of covering the . inside of the duct with sound absorbing material, and as most of these coverings are not fire-proof, a fire -hazard is introduced. In the Zonolite .patented style of construction, the duct is " constructed; of specially designed wire Zonolite all-mineral roof block as installed on Chrysler Engineering Building. 961 Insulation Wilson & Co. I N S U LAI hies 0 N s\ /a n FILTERAI RE Wilson & Co. A L --------- W--W AIK M ASHLAND AVE. CHICAGO, ILLINOIS H A I R C R A F T, HAIRBESTOS and NATURZONE INSULATION Modern specifications are demanding in sulating materials that not only give adequate protection, but also lend them selves to the contours of modern design. For this purpose, Wilson's Haircraft and Hairbestos (flexible blanket type materials) are ideal. Haircraft is made with 100 per cent hair filler between Kraft Duplex Asphalt paper, stitched in rows every 2 in., the width of the material. It has a low conductance of 0.26 in a oneinch thickness. Hairbestos is of the same character as Haircraft, with the exception that it is fire-resisting and covered with crinkled asbestos paper. Naturzone insulation is the standard board form of insulating material for use where a rigid form of material is necessary. It is made of sterilized, deodorized hair compressed into board form of standard size, 36 in. x 16 in. x 1 in., 1^4 in., 2 in. and 3 in. thick. It has a conductivity of 0.27 per square foot per hour per inch of thick ness. The ability to knit itself into a single unit in a very short time makes the efficiency of Naturzone a superior form of insulation. F I l T E R A I R E AIR FILTERS maintain an expanded condition, pressing constantly outward against the sides of.the, container, preventing packing and sag ging. A special fixative maintains the form of the entire pad. The outlet side of the pad is treated with a special adhesive oil for catching and retaining the dust. Filter Cell Rating In the Filteraire filter, Wilson & Co. has introduced Keratin fibers (animal hair). They are thoroughly sterilized and deodorized and subjected to successive mechanical and chemical treatments. ' In the individual cell, the central por tion is built of fibers which are highly resilient. This characteristic helps to Capacity per cell..... ................ 800 CFM Face velocity-- ...................300 FPM Resistance, per unit (two filters 0.18 in w.g. tandem arrangements). These ratings are for. standard 20 x 20 x 2 or 16 x 25 x 2 Filteraire filters. Special size filters are supplied on order. The fibers on the face of the filter are formed mechanically into corrugations and are not coated with adhesive. This treat ment allows the dust to enter the cell in stead of packing up on the surface, in suring exceptional dust-holding capacity. 962 Insulation, Underground The Ric-wiL Company Agents In Principal Cities Union Trust Bldg. CONDUIT SYSTEMS FOR UNDERGROUND STEAM PIPES new york-chicago-san francisco Established in 1910 Cleveland, Ohio Conduit--Standard conduit is vitrified salt glazed tile or cast-iron with Loc-liP Side Joints, bell and spigot type, unlined or lined. Tile and cast-iron in 24 in. sections, sizes 4 to 27 in. inside diameter. A Super-Strength tile conduit on which laboratory tests by A.S.T.M. 3 point method show an average crushing strength of approximately 3000 x per foot diameter per lineal foot. A light weight cast-iron conduit specially designed for bad water conditions and a heavy cast-iron conduit for extra heavy duty. Base Drain--Standard Base Drain is vitrified salt glazed tile for tile conduit and extra heavy tile or cast-iron for the castiron conduit, in 24 in. lengths. Special U.Type Base Drain to hold return line. Support Blocks for use with round tile construction also available. Pipe Supports--Standard Pipe Sup ports for tile conduit are of the externally supported type with rollers for single or multiple pipes. Load is carried entirely on side shoulders of Base Drain. Pipe Supports for cast-iron conduit are of the internal type and are cast integral with the conduit. Pedestal Pipe Supports also available. Details of Ric-wiL Alignment Guides and Anchors furnished upon request. Insulation--Dry-paC Waterproofed Asbestos Insulation, non-settling and non corrosive--packed into the conduit be comes a solid matted mass without cracks, joints or openings--positively non-capil lary' and water-repellant. Has low con ductivity and insures highest thermal efficiency--non-waterproof kind also fur nished. Lined conduit insulation is in- Cutaway view at pipe support showing how Ric-wiL parte interlock. Note Loc-liP Side Joints and how pipe assembly u independent of the conduit. Cut shows Type DP System, lined conduit, with Dry-paC Waterproofed Insulation. tegrally moulded with lining of diatomaceous earth mixture. Sectional pipe covering, sponge felt, 85% magnesia, etc., can also be furnished. Accessories -- Shutter sleeves, filter cloth, asphalt joint cement, waterproofing compound, manhole covers, and other accessories will be furnished as desired. Engineering Service--Full coopera tion with architects and engineers. Instal lation supervision if desired. Technical Data --- Tabulated Steam Heating Rates, Test Reports, Service Detail Bulletins, Catalog Bulletins, Cen tral and District Heating Bulletins and Architects and Engineers Detail Sheets available upon request. Ric-wiL Cast Iron conduit has ample strength tnth minimum weight for use under roadways, railroad tracks, or other places subject to ex treme loads and ribraHon. It is installed without delays and with out added. con struction or engi neering. , Ric-wiL Unit Steam Main, a prefabricated, ready-to-insiaU unit, lS^i ft long, including conduit (Armco Iron), pipe, insulation, and accessories. Ideal for speed and economy on district heating projects. 963 Insulation, Underground Underground Steam Construction Co. 75 Pitts Street, Boston, Mass. PRODUCTS--Engineering and Contracting of Steam Line Installations. Underground Steam Conduits. USCC0 PRE-CAST CONCRETE CONDUIT This unit marks a long step forward in the economics and mechanics of laying under ground steam lines. Its Outstanding Features Are: Strength resulting from fiat reinforced bell; from the longitudinal joints, and from the fact its sections are 4 feet long, reducing the usual number of joints necessary. Shape which allows 12 per cent greater inside capacity than circular conduit of like diameter. This permits larger pipes in a given size conduit and more room for drainage, pipe supports and. rolls. Ease of Installation resulting from the fact that all top and bottom halves mate. Bottoms may be laid for any distance, the piping installed and then the tops brought up and laid. This speeds up the work and protects idle halves from damage. They ' can be.stored away from the job. Materials are high strength cement, with suitable aggregate, amply reinforced with wire mesh. Pipe Supports are of cast-iron and quickly , installed. They may be placed anywhere in the conduit. The weight of the pipe holds them in place. Joints may be of any standard accepted brand of jointing compound or they may. be of standard Portland cement mortar. 964 Meters, Steam Builders Iron Foundry 23 Codding Street Providence, R. I. Representatives in Principal Cities The CHRONOFLO' ELECTRIC FLUID METER for nearby or long distance transmission of flow rates, quantities, pressures,, temperatures, etc. The SHUNT METER for steam, air and gas. The VENTURI METER for boiler feed water supply, and other main pipe lines. CHRONOFLO METERS AND CONTROLLERS "From hundreds of feet to hundreds of miles" Chronoflo--Mechanically measures flow, pressure, temperature, or position in terms of time; electrically transmits this time duration equivalent of the quantity to any point--or points-- nearby or miles away. There a Receiving Instrument mechanically indicates, records, or registers it. If more desirable the same "impulse'' may be used to operate flow, pressure, temperature, or position controllers. Regular A.C. current is used and accuracy is not affected by voltage variation. Suitable for nearby or long distance transmission over private wires or public tele phone channels. Write for Bulletin 273. _ Shunt Steam Meter, Type Ku$. THE SHUNT METER A low priced, practical, mechanical, meter easily installed and accurate over a wide range. Regularly used by many District Heating Companies for measuring steam sold; also ordered and re-ordered by leading industrial plants to meter steam or air furnished tenants, departments, and processes. The illustration shows the complete meter. Installation consists simply of bolting to flanges in the flow line; no connecting pipe or electric wiring. A portion of the entering steam is deflected by an orifice through nozzles against the blades of a turbine located in the upper or.shunt passageway. The speed of the turbine is kept low by a dampening fan on the vertical turbine shaft, at the bottom end of which is a magnetic drive to the totalizer dials. The meter is installed as a unit in 2, 3 and 4-in. lines; for larger capacities the installation is made in a by-pass around an orifice in the main line. Steam Pressure Rated-Capacity of Saturated Steam--Lbs. per Hour (Meters with largest orifice) Gauge 2W Meter y Meter' V Meter 6' Meter 8* Meter 10* Meter 12* Meter Low Pressure Meters i. K.U Extra Heavy Meters 0 5 15 30 50. 50 100 150 200 250 275 ' 300 600 600 1200 1650 .2000 2650 4150 5000 5700 6300 6600 . 6900 ' 1,400 1.900 2,750 3.400 4,050 6,000 9.500 11.400 13,000 14,400 15,200 15,700 2.530 3,350 4,750 5,850 7,000 10,600 16,600 20,000 22,700 25,200 26.500 27,500 5,660 6,500 7,860 9,550 11,400 22,200 29,000 34,400 39,000 43,200 45,000 46,800 9.850 11,300 13,700 16,600 19,800 39,000 51,000 .60,500 - 68,600 76,000 79,400 82,500 15,200 17,500 21,100 25,600 30,500 60,500 79,200 : 94,000 107,000 118,000 123,000 128,000 19,000 21,800 26,300 31,900 38,000 75,500. 99,000 117,000 133,000 148.000 154,000 160,000 Minimum Capacities equal one-tenth tabulated quantities. Many other smaller and intermediate capacities available. Bulletin No. 255 with complete capacity tables, data sheet and price list mailed upon request. 965 Motors Baldor Electric Co. General offices: 4370 Duncan Avenue, St. Louis, Mo. Single Phase PolyPhase Direct Current New York14 East 17th St. Chicago................ .325 W. Huron St. Detroit___ ,,1034 St. Aubin Buffalo22 Kenton Rd. Boston31 Irvington Milwaukee__J331 North 50th St. Philadelphia____ 2019 Rittenhouse MOTORS 1/30 to 15 Hp Pittsburgh____ ___1438 Park Blvd. Minneapolis_______Vendome Hotel Grand Rapids. 257 Eastern Ave.S.E \ Kansas Citt..........2004 Grand Ave. The Baldor Electric Company has pio neered and developed many, of the impor tant improvements in motor design for heating, ventilating and air conditioning service. _^ For 15 years Baldor has specialized in designing and manufacturing quality built motors exclusively and the phrase "A Better Motor'' is not merely an advertising slogan but a definite manufacturing policy, rigidly adhered to. Every Baldor motor is specially engineered for the particular service intended and each is fully guar anteed. UNIT HEATER MOTOR A complete line of types and sizes for all unit heater applications. Single phase, split phase and D.C. Constant, 2-speed and 4-speed quiet, vibrationless operation. 1 shot lubrication. All with inter-change able frames. Solid, cushion base or ring mounting. VARIABLE SPEED MOTOR For Fans and Blowers 5-speed polyphase motors for blower ventilating and cooling systems. Speeds are regulated by simple, durable, wellengineered controller. At high speed, the motor delivers full load. The lower speeds will be approximately 50, 65, 80 and 90 per cent of full load speed. Many of the famous air conditioned trains are equipped with Baldor Motors. Oversize commutator and dual brushes totally enclosed in dust-proof housing. FEATURES OF BALDOR MOTORS Each motor dynamically balanced. Baldor Motors meet N.E.M.A. standards Sine wave slot construction. ^ for starting currents, efficiency and Interchangeable frames. power factor. ' Solid, cushion base or ring mounting. Approved by central stations. Wool packed sleeve bearings. . No radio interference. - High grade steel ball bearings. ' The BALDOR Line Includes: Single Phase--Repulsion Induction..,--............................................................. M to 1M Hp Capacitor Type............................................................................. Mo to 1J^ Hp Split Phase............ ............... :....................... .......................... Mo to M Hp Direct Current........ .................. .................................................................................. M-to 3 Hp Polyphase--Squirrel Cage......................... -............................. -............................... M to 15 Hp Double Squirrel Cage.......................................................................... 3 to 15 Hp Unit Heater Motors--All Types.................................... .......................................Mo to K Hp Standard Horizontal and Vertical Motors for all applications. Ball Bearings in all sizes. Sleeve bearing up to 2 Hp. ' Bulletins giving complete'information and full technical data sent upon request. 966 Century Electric Company 1806 Pine Street, St. Louis, Mo. Offices and Stock Points In Principal Cities Motors Century Mvliitpeed Squirrel Cage Motore M TO 200 HORSE POWER Especially adapted to meet the variable of constant speed requirements of Fans, Ventilators, Refrigerators and similar ap paratus where adjustable speed change is a requirement .... Built for 2, 3, 4 or more speeds--automatic, push button or manual control.... Wide or narrow speed ranges, such as 1800/1200 or 1800/600 down to 900/450 r.p.m. (60 cycle) .... Conventional open or splash proof type . . . .Special speed combinations are also available .... Ball Bearings or phosphor bronze sleeve bearings. ' Century Slip Ring Induction Potypkaee Motore M TO 250 HORSE POWER Desirable for installations where highstarting torque is required and lowstarting current is desirable or where heavy inertia loads increase the time required to bring the load up to full-speed. This type of motor is adapted to two classes of service--constant speed or adjustable varying speed. The only dif ference between the two installations is the secondary control equipment. Ball bearings or phosphor bronze sleeve bearings. 0 Century Direct Current Motore M TO 150 HORSE POWER Built with shunt or compound wind ings, for all commercial voltages . . . . Open, semi-enclosed, fully enclosed ratings Century Squirrcl^Cage Induction S-Phate Motore M TO 600 HORSE POWER Specially suited for all heavy duty, general purpose application--Stokers, Pumps, Compressors and Similar Equipment. Extremely rigid in construction with liberal mechanical strength and the ability to withstand the shock, pounding and stress of gear, chain or belt drive .... Refined cast-iron frames and end brackets .... Armature commercially inaestruct. jble .... Available in standard of totally enclosed fan cooled types .... Ball bear ings or phosphor bronze sleeve bearing. .... Phosphor bronze sleeve bearings with ring oilers, or grease lubricated ball bearings; aiso vertical ball bearing types .... Constant, variable and adjustable- speed types .... The commutator, the most important part of a Direct Current Motor, is made up of hard drawn copper bars, insulated with amber mica between the bars and mica V rings between the bars and the steel shell used to damp them together.- ALSO Blower Motors. Unit Heater Motors. Cushion Mounted Motors. . Refrigeration Motors. Vertical Motors. 967 Motors and Controllers GENERAL. ELECTRIC COMPANY SCHENECTADY, N. Y. 8U.ES OFFICES. WAREHOUSES. SERVICE SHOP8 DISTRIBUTORS in PRINCIPAL CITIES For Code Wire, Conduit Products, Wiring Devices, 'Insulating Materials, etc., address Merchandise Department, Bridgeport, Conn. HEATING, VENTILATING AND AIR CONDITIONING MOTORS The complete line of motors manufactured by the General Electric Company offers you a motor with*electrical and mechanical characteristics best adapted to each of your compressor, fan or pump application. { QUIET MOTOR THIS MOTOR IS SPECIALLY DESIGNED AND TESTED FOR QUIET OPERATION Application Fans and Centrifugal Pumps Reciprocating Pumps ana Compressors Small Direct Connected Fans . Belted Fans. Centrifugal Pumps Pumps. Compressors. Fans SOME G-E MOTORS AND THEIR USES Speed Type Winding Typ, Horsepower Range Classification Constant or Adjustable Constant Constant or 3-Speed Constant or 2-Speed Constant or Multi-speed Shunt B & CD* Compound B fit CD* Resistance Split Phase KH* Reactance Split Phase' " KX Low Torque Capacitor KC* High Torque Capacitor Repulsion Induction SquirTe! Cage (Low Starting Current) KC* KC* SCR K or KB* KF 1/8-200 1/8-200 1/40-1/3 I/6-I/3 1/50-10 1/4-10 1/8-10 1/8-10 1/4-1000 AW5 Direct Current Single Phase Alternating Current Reciprocating Pumps ' . and Compressors (High Starting Torque) KG 3-100 ' Polyphase Alternating Current Pumps. Compressors. Fans - - Constant or Adjustable Constant Wound ` Rotor , . _ Synchronous \' ' M fit MB* TS Vr-1000 25-2000 Quiet Motor. , This list covers only the principal motors used in buildings, for other types and modifications (Vertical, Enclosed, etc.) refer to nearest sues office. G-E "Quiet Motors" are specially designed and tested for this service and carry a name plate so stamped. The G-E sound insulating bases are applied for each definite' rating and are designed to eliminate critical speed vibra tions for each definite rating. These products are the result of extensive, research in the problem of noise elimination. ", . When writing specifications, ask for motors "designed and tested for quiet operation." KH inAuction fractional This Company will gladly-assist In the solution of any power motor electrical problem in relation to heating and ventilation 968 Motors and Controllers GENERAL ELECTRIC COMPANY SCHENECTADY. N. Y. SALES OFFICES, WAREHOUSES, SERVICE SHOPS and DISTRIBUTORS m PRINCIPAL CITIES For Code Wire, Conduit Products, Wiring Devices, Insulating Materials, etc., address Merchandise Department, Bridgeport. Conn. CONTROL FOR HEATING, VENTILATING AND AIR CONDITIONING MOTORS The right G-E control with the right motor for an application insures ideal operation. The General Electric line of standard control offers manual or automatic equipment for compressors, fans, or pumps driven by any type motor which you require, providing full protection for your motor, especially those listed on the preceding page. For special applications General Electric controllers can be designed to meet your exact requirements. ` The following is a list of typical control equipment applicable to all motors listed on the preceding page. Full voltage automatic starters with thermostatic control for fans, or pumps. Automatic reduced or full voltage starters for synchronous motors driving compressors;, . CR7765 Controller (cover re moved) for Use with Wound Rotor Motors ISHP Manual or automatic speed regulating controllers for wound rotor motors driving fans. Manual full voltage starters for pump motors. Manual speed regulating switches for small capacitor motors driving fans. Capacitors for improving power factor. ACCESSORIES Electrically operated valves. Thermostats. Float switches. Pressure switches. Indicating Push buttons. I CR 7006 -- Full Voltage Magnetic Switchfor Use with Inductor Motors CR106I Fractional Horsepower Motor Starting Switch for Wall Mounting CR-9507-C Electrically ' Operated Valve , Motors and control of one manufacture insure perfect operation, simplifies installation and insures good service forYhe entire installation. ' : . ' This Company will gladly assist la the solution of any electrical problem in relation to heating and ventilation - * See-also Pages 838 and 889 ' 969 Motors and Controllers Westinghouse Electric & Manufacturing Co. East Pittsburgh fWl Pennsylvania Research, Application and Design Engineers will cooperate and solve any electrical problem for heating and ventilating systems. Sales Offices and Service Shops in all Principal Cities Quiet Operating Motors The Westinghouse Company has long recognized the need for quiet operating machinery and has devoted a vast amount of research work to the development of special instruments to measure noise ac curately. The human element, which gives variable results, is eliminated in all testing procedure. Westinghouse Quiet Operating Motors are specially designed and individually For fan drives, the new Westinghouse Type 0-1 Controller offers unusual ad vantages. This unit assembly includes the equipment ordinarily housed in three separate cabinets. Primary Linestarter, A Type CW Variable Speed, Quiet Operating Motor Driving Pan tested under loaded and unloaded con ditions in a sound-proof room. A special nameplate is your assurance of their high standard of quiet operation. Lasting quietness is assured by rigid, unit cast motor frames which contribute to the permanence of bearing alignment and air gap. Rotors are given a special dynamic balance, practically eliminating noises due to vibration. Motor Control Open and Closed Views of Type 0-1 Pen Drise Control, Wall-mounted Types speed regulator and Nofuze breaker for circuit disconnect and protection are all mounted and wired in a neat cabinet for wall or floor * mounting. Installation is greatly simplified and its appearance is improved. Arc Welding . PlexArc A-c. Welder, for Simplified Fabrication 5 hp "De-ion" Combination Linestarter with Magnetic Contactor and Disconnect Switch in same enclosure. Starters, speed regulators, thermostats, switches and Nofuze circuit breakers are available for every requirement. For the fabrication of thin-gauge ma terials such as ducts, Westinghouse offers the FlexArc A-C. welder. Its operation is extremely simple and it uses less than 15 cents worth of power an hour. One man can wheel it easily from place to place. It operates from the ordinary single-phase power circuit. See also Page 819 970 Pipe (Black. and Galvanized) Jones & Laughlin Steel Corporation AMERICAN IRON AND STEEL WORKS Jones & Laughlin Building, Pittsburgh, Pa. WELDED AND SEAMLESS STEEL TUBULAR PRODUCTS J & L Welded Pipe assure exceptional ductility, a quali- JKty that is essential to successful Jones & Laughlin manufactures coiling and bending, and flanging Standard Weight, Extra Strong, and for Van Stone joints. Double Extra Strong Welded Pipe, J & L Seamless pipe can be Black and Galvanized, for steam, used with full satisfaction in either gas, air, water, refrigeration and threaded joint or completely welded sprinkler work. Sizes: in. to 16 in. installations. Ductility, strength and O.D. inclusive. safety--highly developed attributes of J & L Copper-bearing Steel Pipe, when J & L Seamless--make this product es specified, can be supplied in standard pecially adaptable for air, steam, gas and weight, or extra strong, black or gal gasoline lines, boilers, refineries, dry kilns, vanized. Use of this product is recom refrigerating systems and other exacting mended for long life, where piping is to be applications. exposed to the atmosphere or other alternate wet and dry conditions. J & L Hot Rolled Seamless Jones & Laughlin Steel Pipe is made of soft, weldable steel rolled from solid ingots made to a special analysis which, checked over a period of years, has proved to be very uniform in quality. The steel pipe produced from this special grade of J & L Steel is soft and ductile, free cutting, strong at the welds, and free from excess scale. J & L Pipe is commercially straight and free from blisters, cracks or other injurious defects and is well within the allowable tolerances as to dimensions and weights, and true to round in the outside diameter. Careful attention is given the threading of the pipe with good clean-cut threads fitted with sound couplings correctly tap ped to give a tight joint. Soft, ductile steel of free cutting.quality enables the con tractor to-cut clean, sound threads on the job. The Jones & Laughlin process of gal vanizing assures a thorough coating and insures against pipe being clogged with spelter. The surface of the pipe is care fully cleaned so that when the galvanized coating is applied it adheres strongly and does not tend to flake off. Steel Boiler Tubes J & L Seamless Boiler Tubes are manu factured in accordance with the A.5.M.E. Boiler Code and comply with the A .S. T.M. Specifications and the rules and regulations of the Bureau of Navigation and Steam boat Inspection of the U. S. Department of Commerce. They are supplied in a full range of standard sizes, from 1 in. O.D. to 6 in. O.D. inclusive. The process by which Jones & Laughlin manufactures seamless boiler tubes is largely responsible for the unusually high ductility of the product. It is a process in which a forging action is predominant. This forging action gives to the steel the greater density and higher ductility that may be expected of any forging operation. It makes it stronger yet more pliable and, therefore, more easily formed in its cold state. Forging also effectively eliminates any such imperfections as air holes or. blow holes that may be present in the steel. . Inspection of this product begins with the careful selection of the steel for the billets and continues without interruption through every stage of manufacture. It is your assurance of receiving only the very J & L Seamless Pipe finest boiler tubes that can be manu factured. J & L Seamless Pipe is made in three weights; standard, extra strong and double extra strong. Sizes: in. nominal to 14 in. O.D. inclusive. J & L Seamless Steel Pipe is pierced from a solid billet--there are no welds. The result is dependable and uniform wall strength. The method of manufacture, and the use of only specially selected steel, Other J & L Tubular Products J & L also manufactures. Reamed and Drifted Pipe in sizes 1 in. to 6 in. inclusive. Dry Kiln Pipe, Pipe for Refrigeration Service, Water Weil and Irrigation Casing, Line Pipe and a complete line of Oil Country Tubular Products in welded and seamless. 971 Pipe and Tubing, Copper The American Brass Company General Offices--Waterbury, Conn. Manufacturing Plants: Ansonia, Conn., Torsington, Conn.. Watbrburt, Conn.. Buffalo, N. Y., Detroit, Mich., Kenosha, Wis. Boston. Mass.. One Forty Federal St. Syracuse. N. Y., 207 E. Genesee St Providence, R. I., 131 Dorrance St New York N Y., 25 Broadway New*ax, N. J,, 20 Branford Place Philadelphia, Pa., 117 Sonth 17th St. Offices and Agencies: Washington, D. C.. 1511 K St., N.W. Chicago, III., 1326 W. Washington Blvd. Atlanta, Ga., 10 Forsyth St. Sr. Louis, Mo., 408 Pine St. Pittsburgh, Pa., 535 Smithfield St. Houston, Texas, 609 Fannin St. Cleveland, Ohio, 925 Euclid Ave. San Francisco, Calif., Dayton, Ohio. 32 North Main St 235 Montgomery St. Cincinnati, Ohio, 101 West 4th St Los Angeles, Caup., 411 West Fifth St. CANADIAN PLANT: Anaconda American Brass Limited. New Toronto. Ontario PRODUCTS--Anaconda Deoxidized Copper Tubes and Fittings; Anaconda "85" Red-Brass Pipe; Anaconda "67" Brass Pipe; Everdur Metal for storage heaters, storage tanks, ducts and air conditioning equipment Anac&ndA . from mine to consumer ANACONDA DEOXIDIZED COPPER TUBES After studying performance records, The American Brass Company endorses Anaconda Copper Tubes, connected with solder fittings, in sizes up to 2 in. where conditions of pressure and heat are normal. Copper Tubes available in long lengths and coils may be bent for ordinary turns and offsets, offering obvious instaflation advantages. Anaconda Copper Tubes are drawn to the accurate size required for use with solder-type fittings. Anaconda Copper Tubes are furnished in two wall thicknesses--Type "K" and "L." Type K, the heavier, conforms to U. S. Government Spec. No. WW-T-799 and A.S.T.M. Spec. No. B-88-33. Ana conda Type K Tubes are recommended for: 1. Underground water service lines. 2. Hot and cold water lines. 3. Sprinkler systems. 4. Low pressure steam lines. 5. Oil Burner suction and return lines. Anaconda Type L Copper Tubes meet Government and A.S.T.M. Specifications for this class and are considered suitable for interior plumbing, although the heavier grade, Type K, is preferred. Data on the comparative wall thicknesses and weights are included in the accompanying table. Lengths and Coils--Anaconda Deoxi dized Copper Water Tubes in sizes up to and including 1J4 in. are furnished soft in 30, 45 and 60-ft coils; also hard or soft in 20-foot straight lengths. Sizes over 1 in. are furnished hard or soft in straight lengths only. Weights of Anaconda 67 Brass, 85 Red Brass and Copper Water Tubes Nom inal Size In. - Diameters--Inches - S.P.S. Pipe Copper Water Tubes Type K Type L Outside Inside Outside Inside Outside Inside Wail Thickness Approx. Weights--Pounds per Foot Inches Copper Water S.P3. Pipe Copjjer Water SP3. Tubes Pipe 67 85 Red Type K Type L TypeK Type L Brass Brass Copper -0.405 v5 0.540 Vt 0.675 Vi 0.840 1.050 i4 1.315 iy4 1.660 21 1.900 2.375 V/j 2.875 3 3.500 W7 4.000 4 4.500 0.281 0.375 0.494 0.625 0.822 1.062 1.368 1.600 2.062 2.500 3.062 3.500 4.000 0.250 0.375 0.500 0.625 0.875 1.125 1.375 1.625 2.125 2.625 3.125 3.625 4.125 0.186 0.311 0.402 0.527 0.745 0.995 1.245 1.481 1.959 2.435 2.907 3.385 3.857 0.250 0.375 0.500 0.625 0.875 1.125 1.375 1.625 2.125 2.625 3.125 3.625 4.125 0.200 0.315 0.430 0.545 0.785 1.025 1.265 1.505 1.985 2.465 2.945 3.425 3.905 .0620 .0825 .0905 .1075 .1144 .1265 .1460 .1500 .1565 .1875 ,7190 .2500 .2500 .0320 .0320 .0490 .0490 .0650 .0650 .0650 .0720 .0830 .095 .109 .120 .134 .0250 .0300 .0350 .0400 .0450 .0500 .0550 .0600 .0700 .080 .090 .100 .110 0.246 0.253 0.259 0.437 0.450 0.460 0.612 0.630 0.643 0.911 0.938 0.957 1.240 1.270 1.300 1.740 1.790 1.830 2.560 2.630 2.690 3.040 3.130 3.200 4.020 4.140 4.230 5.830 6.000 6.140 8.310 8.560 8.750 10.850 11.170 11.410 12.290 12.660 12.940 0.085 0.134 0.269 0.344 0.641 0.839 1.040 1.360 2.060 2.920 4.000 5.120 6.510 0.068 0.126... 0.198' 0.284 0.454 0.653 0.882 1.140 1.750 2.480 3.330 4.290 5.380 Note--S.P.S. Pipe available up to and including 10 in. Copper Water Tubes up to and including 8 in. Other Beamless tubes'up to 26 in. O.D. . - 972 Pipe and Tubing, Copper The American Brass Company ANACONDA COPPER TUBE FITTINGS A complete line of Anaconda Fittings, both solder and flared tube types, is available for the assembly of copper tubes. For size range of fittings, see accompanying table. All three following types of fittings are furnished in elbows, tees, couplings and unions, including a complete range of reduction and adapter combinations. Solder fittings are checked with maximum and minimum gages to insure accuracy and the close tolerance required for dependable solder connections. Wrought Copper Solder Fittings-- Provide copper to copper connections, are uniform in quality and free from porosity. Generous depth of cup and unusually high shoulder give well made joints an extra factor of safety. Cast Bronze Solder Fittings--Are made of "steam bronze" alloy (85 percent copper, 5 per cent zinc, 5 per cent tin and 5 per cent lead). All cast fittings are care fully gauged and checked by air pressure under water. Test joints (% in.) withstood a straight pull of 7000 lb at 70 F and 1500 lb. at 210 F. At all temperatures between 70 and 210 F, test joints withstood in ternal pressure exceeding 2000 p.s.i. Solder--That used in the foregoing tests was 95 per cent tin--5 per cent antimony-- the alloy recommended for best all-around results. Melting point is 465 F.; cooling range is only 15 F. "Hard" solder is, of course, ideal, and where unusually high temperatures are en countered,' it is recommended that a high strength, high melt point solder such as Sil-Fos be used (1300 F). Cast Bronze Flared Tube Fittings-- Serving a definite need for assembling soft tubes in sprinkler systems, under ground lines, etc., these fittings are also made of "steam bronze" alloy. Anaconda Deoxidised Copper Tubes-- Types "K" and "L"% in. to 8 in. incL Anaconda Wrought Copper Solder Fittings-------------------------------------------- in. to 2 in. incL Anaconda Cast Bronze Solder Fittings__34 in. to 10 in. incL Anaconda Cast Bronze Solder Valves: Gate Valves--------------------------------------% in. to 2 in. incL Globe and Stop and Drain Valves--.^ in. to 1 in. incL Ananconda Cast Bronze Flared Tube Fittings-------------------------------------------- 34 in. to 2 in. incL ANACONDA "85" RED-BRASS PIPE Anaconda "85" Red-Brass Pipe is offered as the highest quality corrosionresistant pipe commercially obtainable at a moderate price and is recommended for use in localities where highly corrosive water conditions prevail. These waters may be relatively low in hardness, high in carbonic acid gas content and low in alkalinity. Anaconda "85" Red-Brass Pipe con tains 85 per cent copper and conforms to government specifications for Grade "A" water pipe. The words "Anaconda 85 Red-Brass" are stamped in the metal at intervals of one foot throughout each length. ANACONDA "67" BRASS PIPE Anaconda "67" Brass Pipe can be depended upon to give lasting service in all localities where normal water conditions prevail. . Anaconda "67" Brass Pipe contains67 per cent copper and conforms to government specifications for Grade "B" water pipe. It can be identified by the numerals "67" following the name "Anaconda" stamped in the metal every 12 in. in each length. Anaconda Publication B-l describes Anaconda Pipe, Tubes and Fittings in de tail, and offers suggested methods of assembly. Write for it. *Everdur Tanks--Nearly all copper, Everdur is a special non-rust alloy which combines the strength of medium carbon steel with ready weldability. It is an ideal material for durable, rustless water tanks of every description--from domestic range boilers to giant storage heaters for hotels, laundries, hospitals, textile plants, schools or breweries. Everdur is made in all commercial shapes, including tank plates which have physical properties as given in A.S.T.M. tentative specifications B96-34T. For ad ditional data, and names of fabricators, address our nearest office. . Everdur for Air Conditioning Equip ment--Everdur Metal has been used with marked success for fans and blowers, ducts, humidifiers (air washers) and for various cast and wrought parts of other equipment items subject to corrosive influences. Because of its strength and welding properties, Everdur may be substituted for steel in the same gauges, fabricated by substantially the same methods, and with the same equipment. . . "Everdur" is a registered trademark identifying pro ducts of The American Brass Company made from alloyB of copper, silicon and other elements. . 973 Pipe and Tube, Copper Chase Brass & Copper Co Incorporated Subsidiary of Kennecott Copper Corporation . Waterbury For data on Chase Copper Radiators see page 999 Connecticut , RUSTLESS HEATING LINES OF CHASE COPPER TUBE AND CHASE SWEAT FITTINGS Here are a few reasons why copper tube should be used for heating lines. 1. Copper does not rust, therefore the water or steam inside the lines remains clean. 2. Absence of rust and scale formation assures permanent original steam or water carrying capacity. 3. The resistance to flow in copper tube is low. 4. Delicately adjusted thermostatic valves and traps are not rust-clogged out of commission. 5. Copper is inexpensive and as satisfactory for giving service as any material known. TEMPER--Both hard and soft tubing are available for heating lines. In remodelling work, and in replacing old heating systems the soft copper tube will be found par ticularly useful. It can be worked down between walls and around comers, long 60 ft. coils eliminate many useless connections. For all soft copper tube we recommend the extra heavy gage, (known by United States Government specifications as "Type K"). For the average new installation we recommend the light gage copper tube ("Type M"). PRESSURE--Chase copper tube is adaptable for all low pressure heating systems. While we do not recommend the use of copper tube with any steam system having more than 30 lb. pressure, the factor of safety over such pressure is very great. The bursting pressure, for example, of % in. Chase copper tube and sweat fittings when connected together is 3,050 lb. per square inch. RETURN LINES--While we recommend copper tube for all heating.lines, it is in the . return lines that the greatest amount of rusting takes place. Architects and Engineers have learned by experience that these are the lines that are apt to rust and in some instal lations need replacement, after a very short period of service. CATALOG--The information on these two pages is necessarily brief. If you would like the detailed story write for a copy of our book, Chase Copper Tube for Heating Lines." This is a typical vapor installation. Notice the neatness of the copper tube and sweat fitting heating lines. Also the absence of union connections. 974 Chase Brass & Copper Co. Pipe and Tube, Copper CHASE COPPER TUBE FOR HEATING LINES Copper lube and sweat fittings are used for the run-outs from main to risers. This minimizes resistance to flow of steam. _ Steam Carrying Capacities The steam carrying capacity of copper tube is greater than that of iron pipe of the same nominal size. For example, in a steam main, 2 in. copper tube is capable of taking care of a load of 444 sq. ft. of radiation as compared with 386 sq. ft. for 2 in. iron pipe. This is an increase of 15.1 per cent. For equal steam pressure drop the capacity of copper tube is on the average 10 per cent greater than for the same nominal size of iron pipe. Because of this it is frequently possible to use tube of smaller size. Pipe Covering Copper Water Tube uses the same standard pipe coverings as other heating pipes, but in most cases requires one size smaller covering. This is a saving in the cost of covering. Costs The slight extra cost of Chase copper tube and sweat fittings is a very small amount in dollars to pay for the advantages of a copper tube installation. SIZES AND WEIGHTS Nominal Size V% Inch ,% z 1. \\VYif M- 2" J/2 " .3 l'/2 z 4 44 Outside Diameter 0.625 Inch 0.875 " 1.125 " 1.375 44 1.625 " 2.125 M 2.625 44 3.125 44 3.625 M 4.125 * Inside Diameter 0.569 Inch 0.811 M 1.055 44 1.291 " 1.527 " 2.009 ** 2.495 44 2.981 " 3.459 " 3.935 " Wan Thickness 0.028 Inch 0.032 r 0.035 ** 0.042 " 0.049 0.058 44 0.065 ** 0.072 44 0.083 44 0.095 44 Pound per Lineal Foot 0.203 Lbs. 0.328 44 0.464 " .0.681 0.940 44 1.46 " 2.03 M 2.68 44 3.58 " 4.66 44 .. See also Page 999 975 Pipe and Fittings (Copper) Albany, N. Y. Atlanta, Ga. Boston. Mass. Buffalo, N. Y. Chicago. III. Cincinnati, Ohio Cleveland, Ohio. St. Louis, Mo. Mueller Brass Co. Port Huron, Mich. Branch Offices and Representatives In Principal Cities Dallas, Texas Dayton, Ohio Denver, Colo. Detroit, Mich. Flandreau, S. D. Flint, Mich. Grand Rapids, Mich. Harrisburg, Pa. Indianapolis, Ind. Kansas City, Mo. Los Angeles, Calif. Milwaukee, Wis. Minneapolis, Minn. Mobile, Ala. Canadian Sales s md Manufacturer Canada Wire and Cable Co,, Ltd., Toronto, Cai Newark, N. J. Philadelphia. Pa. N. S. Pittsburgh, Pa. Rochester, N.'Y. San Francisco. Calif. Sarasota, Fla. Seattle, Wash. Washington, D. C. PRODUCTS--STREAMLINE Copper Pipe and Seamless Tubes; STREAMLINE Hard Copper Pipe and Fittings; Valves and Flared Fittings for Mechanical Refrigeration; STREAMLINE Refrigeration Fittings; Forgings of Brass, Bronze and Copper; Castings of Brass and Bronze; Rod; Screw Machine Products; Fabricated Parts and Special Nickel and Chromium Plated Parts. Coupling Copper to Copper Copper to Outside l.P.S. 45 Deg Elbow' Streamline Copper Pipe and Fittings for heating, plumbing, air conditioning and industrial use are made by the Streamline Pipe and Fittings Co., Division of Mueller Brass Co., Port Huron, Mich. . .' The Streamline Fitting is the original solder type fitting, introduced and manu factured by the Mueller Brass Co. of Port Huron, Mich. It incorporates many advan tageous features and has proved to be the revolutionary advance' of the age in the development of piping systems for plumbing and heating.and for many industrial uses. The Streamline Fitting is not connected either by threading or flaring, but by soldering. The outside surface of the copper pipdvand the inner surface of the Stream line fitting are cleaned with sandcloth, and solder, flux is then applied to the cleaned surfaces to eliminate oxidation when the assembled joint is heated. The joint is then sufficiently heated with a blow or acetylene torch and the soldering operation is per formed by feeding wire or stick solder through the.feed hole in the fitting. The Streamline Fitting alone has the solder feed hole, groove and taper'. The solder feed hole, through which the solder is introduced, enters directly into an internal feed channel. The feed channel is located equidistantly between the internal shoulder against which the pipe rests and the outer edge of the fitting. When solder is introduced it is distributed by capillarity from the feed channel and distributed evenly and thoroughly between the bonding surfaces, traveling inward to the shoulder and outward to the edge of the fitting where it appears as a continuous solder ring around the full circumference of the pipe. This ring, and feed hole completely filled with solder, constitute positive proof to the operator that the joint is permanently leak-proof. An actual pressure test is not necessary. '" 976 Pipe and Fittings (Copper) Streamline Pipe and Fittings Co. Port Huron, Mich. DIVISION OF MUELLER BRASS CO. 90 Deg Elbow Tee Copper to Inside I. P. S. Crosses The tapered ends, since they are the thinner sections of the fitting, hasten the cooling of the solder at these points and facilitate the completion of the joint. The solder may be fed from any position, whether the feed hole is located at the top, side or bottom. Owing to the never failing phenomena of capillarity, the solder will flow up, down or laterally with equal facility. Streamline Copper Pipe is a seamless cold drawn copper tubing conforming to A.S.T.M. B 88-33. For most piping purposes, hard drawn pipe is used though annealed material is supplied where bends are to be made. Three weights of Streamline Copper Pipe, Govt. Types K, L and M, are made in all sizes, and an additional lighter weight is made in sizes 3 in. and larger. The latter is used mainly by the paper industry for pressures not over 125 lb. This range of weights permits its use for water or air pressures up to 400 lb. Streamline Fittings are furnished in sizes from % in. to 12 in. inclusive with a full range of reducing sizes. Fittings above 6 in. are flanged and may be had with either A.S.A or rivetted pipe standard flanges. Mating flanges are soldered to the pipe. The Streamline Fitting permits the use of thin-walled copper pipe and places a non rusting, non-clogging piping system within the reach of the ordinary investor. Vibration is not localized at the joints, but is harmlessly dissipated throughout the system. Copper Pipe has the property of transferring the heated element (steam or hot water) from the point of generation (boiler) to the radiators quickly and with slight temperature drop. During the last five years architects and engineers have used Streamline Copper Pipe and Fittings successfully in every type of building construction and in thousands of installations throughout the United States and Canada. . In addition to its rust, clog and vibration-proof qualities and long life. Streamline has many other advantages such as the reduction in size of pipe lines and radiator con nections from those nominally used, a neat, compact installation requiring a minimum of space and important advantages in industrial and drainage applications. There is a Streamline product for every piping requirement. 977 Pipe and Sheets Republic Steel Corporation General Offices Cleveland, Ohio Birmingham. Ala. Boston. Mass. Buffalo, N. Y. Chicago, III. Cincinnati. Ohio Cleveland, Ohio Denver, Colo. Detroit, Mich. Grand Rapids, Mich. Houston, Texas Indianapolis, Ind. Kansas City, Mo. Los Angeles, Calif. Milwaukee, Wis. New York, N. Y. Philadelphia, Pa. Pittsburgh. PaSalt Lake City, Utah San Francisco. Calif. General Export Dept.: New York City Seattle, Wash. St. Louis, Mo. St. Paul, Minn. Toledo, Ohio Tulsa, Okla. Washington, D. C. Youngstown, Ohio TONCAN COPPER MOLYBDENUM IRON What Is Toncan Iron ? Toncan Iron is a highly <jqncan;:IU3S.JiU.Cff. Toncan Iron Sheets Toncan Iron is available in various sheet forms. refined open hearth iron COPPER Plain sheets may be had with which is alloyed the correct proportion of. cop IRON black or galvanized, in gauges No. 8 to 28, widths per and molybdenum. As from 24 to 50 in., and such, it possesses the lengths from 10 to 13 ft., maximum rust-resistance of any ferrous depending upon gauge and width. The material in its price class. Toncan Iron trade mark is stenciled in Thousands of rigid tests and the per two or three places on every sheet. formance of untold tons of Toncan Iron in actual service point to the greater economy in the heating and ventilating systems of which the sheet metal and pipe are Toncan Iron. Toncan Iron Pipe Toncan Iron Pipe is available in standard and extra heavy weights; black or galvanized; in sizes from 14^-inch to 16-inch O.D. All Toncan Iron Pipe, 2-inch Advantages of Toncan Iron and larger, is electric resistance welded, (1) It resists to a higher degree more of ' the many and varied types of corrosion than any other ferrous material in its price class. This resistance is not confined to the surface or "skin" of the metal, but is uniform throughout. (2) It combines the high rust-resistance of an alloy iron with many of the desirable physical qualities of less resistant ferrous materials. and combines the foregoing advantages of Toncan Iron with the advantages of Republic's electric welding process--100 per cent weld, perfect roundness, uniform diameter and wall thickness, and freedom from scale. Toncan Iron Pipe, "black" finish, is painted blue; galvanized finish is marked with two blue stripes. Couplings are stamped TM. Source of Supply (3) It is one of the most workable of Toncan Iron Sheets and Pipe , are materials. Sheets form easily. Pipe may stocked by jobbers in all large cities; lead be handled like any iron. ing contractors everywhere use Toncan (4) Unlike other ferrous materials, cold Iron and are glad to supply it where working--cutting, bending, punching, specified. If, for any reason, you cannot threading, etc.--in no way affects the rust- obtain Toncan Iron, write to Republic's resistance of Toncan Iron. nearest sales office. . (5) It welds easily by any of the usually accepted modern methods. The use of Toncan Iron welding rod insures an instal lation of equal rust- and corrosion-resis tance throughout. (6) A uniform and tightly adherent galvanized coating can be applied, thus adding the protection of a heavy coating of Literature Two 64-page books, "The Path to Permanence" on Toncan Iron Sheets and "Pipe for Permanence" on Toncan Iron Pipe, will bring you the complete story. Write for your, copies. Other Republic Products zinc to the already high rust-resistance of Republic Steel Corporation manufac the base metal itself. tures hundreds of iron, steel and alloy (7) Through its longer, trouble-free life, products, among which of interest to it has been found to cost far less per year heating and ventilating engineers are of service. Its use is more than an econo Enduro Stainless Steel in sheets and other my. It is insurance against early sheet usual forms, steel pipe, and steel or and pipe failures and costly replacements. Toncan Iron boiler tubes. ' 978 Pipe and Tubing Revere Copper and Brass Incorporated Executive office:. 230 Park Avenue, New York City MILLS--Baltimore, Md., Taunton, Mass., New Bedford, Mass. Rome, N. Y.t Detroit, Mich.. Chicago, III. SALES OFFICES--Boston, Mass., Providence, R. I., Philadelphia, Pa., Atlanta, Ga., New Orleans, La., New York, N. Y., Pittsburgh, Pa., Cleveland, Ohio, Cincinnati, Ohio, Grand Rapids, Mich., Milwaukee, Wise., St. Louis, Mo., Minneapolis, Minn., Dallas, Texas. Seattle, Wash., San Francisco, Calif.. Los Angeles, Calif, REVERE COPPER WATER TUBE Revere Copper Water Tube is recom mended for heating lines, refrigerant lines, heat control lines and for other heating and ventilating piping. This tube is seamless, 99.9 per cent pure copper, completely deoxidized, with a gun-barrel finish inside. It is furnished in three types known as "K," "L," and "M," which meet Govern ment and A.S.T.M. specifications. In general the Type "K" is used where cor rosive conditions are severe, and types "L" and "M" where these conditions are normal. For most heating work, Types "L" and "M" are satisfactory. Types "K" and "L" are furnished in both hard and soft tempers; Type " M " in hard temper only. -The hard temper is used for new and exposed work; the soft temper for hidden replacement work and where flexibility is essential. Fittings--This tube is joined with Streamline soldered fittings or with any standard make of compression fittings. Thus, threading is eliminated and metal in S.P.S. pipe used only for cutting threads is saved. The wall thickness of Revere Copper Water Tube is uniform throughout and the joints are leak-proof, vibration proof and stronger than the tube itself. The Streamline fitting is so made that friction is reduced to a minimum and partial stoppage due to the lodgment of sediment, etc., js prevented. been found practicable to install Copper Water Tube in smaller sizes than in the case where rustable pipe is used. The same holds good for some steam in stallations. 4. In general, pipe covering can be one size smaller with Copper Water Tube than for the same size S.P.S. pipe because of the smaller outside diameter of the tube. Concealed Radiation--Revere manu factures two distinct types of convectors; the Robras, box fin type, and the Rocop, tubular convector, which meet almost all conditions of service, price, etc. To Heating and Air Conditioning Manufacturers--Revere Engineers are anxious to cooperate with manufacturers of heating and air conditioning equipment and to make recommendations with refer ence to the use of non-ferrous products. Revere Copper Water Tube STANDARD DIMENSIONS AND WEIGHTS TYPE K TYPE L TYPE M in O.D. Wall Wt WaU Wt WaU Wt In. in Thick- Lbs. Thick- Lbs. Thick- Lbs. In. ness per Ft ness per Ft ness per Ft In. In. In. y .500 .049 .269 .035 .198 .025 .144 Vz .625 .049 Vi .750 .049 % .875. .065 344 .040 .418 .042 .641 .045 .284 .028 .362, .454 .032 .203 .328 Advantages of Revere Copper Water Tube--In brief these are as follows: 1. Revere Copper Water Tube has 1 1.125 V/, 1.375 Wi 1.625 .065 .065 .072 .839 .050 1.040 .055 1.360 .060 .653 .035 .882 .042 1.140 .049 .464 .681 .940 many installation advantages which make for economical first cost, as well as main tained economy. With Streamline Fit tings it can be installed in a minimum of space. The soft temper tube can be bent where needed, as for example, around spandrel beams. This saves installation time and eliminates fittings. Furring is greatly reduced. Joints may be easily disassembled. 2. Revere Copper Water Tube cannot rust, so that it is not necessary to install oversize pipe. Life-time service is assured for all uses. Flow is smooth and uninter rupted and turbulency and noises are greatly reduced. 3. In forced hot water systems, it has 2 2.125 .083 2.060 .070 1.750 .058 1.460 2V4 2.625 .095 2.920 .080 2.480 .065 2.030 3 3.125 .109 4.000 .090 3.330 .072 2.680 Wl 3.625 .120 5.120 .100 4.290 .083 3.580 4 4.125 .134 6.510 .110 5.380 .095 4.660 5 5.125 .160 9.670 .125 7.610 .109 6.660 6 6.125 .192 13.870 .140 10.200 .122 8.910 8 8.125 .271 25.900 .200 19.290 .170 16.460 Recommended Operating Pressures Type K--Hard Temper..up to 400 pounds Type K--Soft Temper_____ ______________up to 250 pounds Type L--Hard Temper-_______ _________ up to 250 pounds Type M--Hard Temper,up to 250 pounds Tempers and Lengths : Type K \ Hard Temper In straight 20 ft. lengths. Type L / Soft Temper in 30 ft., 45 ft., and 60 ft., coils. Type> M--Hard Temper in straight 12 ft and 20 ft lengthy. 979 Pipe and Tubing (Copper) Wolverine Tube Company SEAMLESS COPPER, BRASS AND ALUMINUM Main Office and Mill: 1411 Central Avenue, Detroit, Mich. New York Office: 420 Lexington Avenue Atlanta, Ga........... Boston, Mass......... Buffalo. N. Y.......... Chicago, III Cleveland, Ohio.... Datton, Ohio........ Denver, Colo......... Hartford, Conn..... Los Angeles, Calif. Louisville, Kt........ Milwaukee, Wis.... Sales Offices 411 Georgia Savings Bank Bldg. ....................................205 A Street ......................Court and Wilkeson 129 Si Jefferson St. 1740 E. Twelfth St. ......................... ..........Route No. 9 .........................1210 California St. .......................... -186 Hamilton St. ....1015 E. Sixteenth St. .............Ill N. Fifth St. ...... 647 W. Virginia St. Minneapolis, Minn............ Philadelphia, Pa............... Pittsburgh, Pa................... Portland, Ore._ Richmond, Va-- St. Louis, Mo..... San Francisco, Calif......... Toronto, Ontario. Washington, D. C. Seattle, Wash...... __ 529 S. Seventh St. __229 N. Twelfth St .1228 Brighton Road ,,103 N.W. 14th St. ___ __ Mutual Bldg. .......4067 Park Ave. ________ 7 Front St. _____ 128 Simcoe St ....1108 Sixteenth St .........1005 E. Pike St DEOXIDIZED COPPER WATER TUBING All Wolverine.Tubing is extruded from billets of 99.9 per cent pure copper, which accounts for the very high corrosion re sistance of this tubing. Because of the one step extrusion pro cess, metal flow is uniform and unre stricted. The tube, therefore, has uniform density, unusual strength and a mirror like inside finish. Wolverine Tubing also has an even temper (hard or soft) for easy workability, is free of all scale or sediment, may be frozen repeatedly without bursting and is accurate in dimensions both I.D. and O.D. Any solder or compression type fitting, may be used with Wolverine Tubing to make a perfect joint, due to the close tolerances held in tube diameters. Wolverine Deoxidized Copper Water Tubing is made to U. S. Government WW-T-799 and A.S.T.M. B-68-33 Speci fications under the regular types K, L, and M. Suitable for normal water conditions. Furnished in hard or' soft temper in straight 20 ft lengths, soft temper in 30, 45 and 60 ft coils. Government Type M, A. S. T. M. Class M Suitable for air conditioning and re frigeration installations and for interior plumbing and heating purposes. - Furnished in hard temper in straight 20 ft lengths only. , For use with-soldered fittings only. FABRICATED TUBING Wolverine offers a complete and com petent fabrication service for tube parts. This includes bending, flaring, swaging, brazing, etc. Every operation is held rigidly to size and specification. DEHYDRATED REFRIGERATION TUBING Government Type K, A. S. T. M. Class K Recommended for air conditioning, re frigeration, oil burner and plumbing installations. Particularly suited to under ground lines and where water conditions are severe. Also for Gas, Steam and Oil Lines and Industrial Uses. Sizes up to 2 in. approved by Under writers' Laboratory. Furnished in hard or soft temper in straight 20. ft lengths, soft temper in 30, 45 and 60 ft coils. Government Type L, A. S. T. M. Class L For oil burner, air conditioning, re frigeration and general plumbing uses. Wolverine Dehydrated Soft Copper Refrigeration Tubing is guaranteed to meet' A.S.T.M. Specification B-68-33. The ends of each coil of dehydrated refri geration tubing are solder sealed and crimped in the form of the Wolverine "W." Wolverine Refrigeratiori Tubing, in securely wrapped coils, is now available. This spiral crepe paper wrapping protects the coil against atmospheric contact, dirt and other foreign matter. It keeps the tubing absolutely clean until ready for use and it gives the service man a compact package to save room in his kit. Your local refrigeration jobber can supply you with any quantity or size of Wolverine Tubing. Large stocks carried in the mill at all times for prompt ship ment. 980 Publications American Society of Refrigerating Engineers 37 West 39th Street, New York, N. Y. REFRIGERATING DATA BOOK REFRIGERATING ENGINEERING T NHE current (second) edition of the biennial Refrigerating Data Book con stitutes a one-volume encyclopedia on OW in its 31st volume, Refrigerating Engineering is published in a highly popular form with fully illustrated cover refrigeration in all its applications by thirty of the leading ex perts in the field. The editorial and with a wide range of refrigerating topics, treate d every month by the ablest men. This maga policy is to include all the funda mental infor mation on the art of refrigeration and to in- zine at the same time carries as a scientific sec tion the pro ceedings of The Ameri can Society of elude as much of the practical ap plication data as pos sible. The book is thus useful for the novice as well as the experienced practi Refrigerating Engineers, which have given the magazine its unquestioned authority. .. The editorial policy is to foster a spirit of independent tioner. In 470 pages of text data in five technical inquiry into all questions which parts, its 30 chapters go into the theory, arise in the refrigerating industries, to give the means and machinery of refrigeration, the reader a chance to share the perspec and its applications. Several chapters tive of the experienced people who write deal with air conditioning in theory and for its pages, and to bring him also the practice. In hard leather binding, $3.50 necessary background information on each in the United States. A third edition topic discussed, so he may know its con (1936-38) appears in the fall of 1936. nection with current affairs. The rate is $5.00, with lower introductory rates HOW TO FIGURE AIR occasionally offered. CONDITIONING CODES AND STANDARDS A TNEW popular book, called "How to Figure Air Conditioning,'' by Harold M. Henrickson, an able engineer and writer, assembles not only the element HEyl.5.i?.E. has a number of technical codes in its series of Circulars. Recent additions include the code for testing and ary facts, but shows computations for the rating mechanical condensing units (No. design and application of various types of 13, 15c) and the code for testing and rating air cooling and conditioning as actually air conditioning equipment (No. 14, 20c). done in the field. In cloth $1.00, postpaid; Other current data; Plant test code, cor- 40 pages, with a psychrometric chart and orsion prevention code, safety code, code . numerous working examples, definitions for testing iced refrigerators. Write for and the like. Treats systems with and free booklet Pointers to Authors, including without refrigeration for summer con style sheet and directions for locating in ditioning. The first thing of the kind! formation in refrigeration. Just published! Publications American Artisan Published by KEENEY PUBLISHING COMPANY 6 North Michigan Avenue, Chicago, 111. merican A ARTISAN covers the field of warm air heating, sheet metal contracting and residential air con ditioning. For more than 50 years AMERICAN ARTISAN has served the warm air heating and sheet metal con tracting industry. Then, as residential air conditioning began to develop and it became apparent that its growth was to be along the lines of the'central, forced warm air heating system, with duct distribution of the conditioned air, AMERICAN ARTI SAN naturally expanded to include it. In every issue AMERICAN ARTISAN carries a special section, titled "Air Con ditioning," to give specialized attention to the subject of air conditioning for homes and small structures: Its readers are warm air heating and sheet metal contractors, jobbers and manufacturers, together with engineers who take it for its thorough air condition ing coverage of the home field. As the demand for residential air con ditioning began to develop, the advantages of the warm air type of heating system, either direct or indirect, with its duct distribution of air, became apparent. This type of system was readily adapted to all factors of air conditioning, either through a self-contained central unit or through a central furnace to which could be added, step-by-step or as a whole, fan, washer, humidifier, filters, controls, cooling and automatic firing. Today, as a result of this ready adapta bility as well as economy, thousands of homes have winter air conditioning-- forced warm air heating with air cleaning and humidification. These homes are ready for summer cooling to be attached to the same system to give them complete year- 'round air conditioning. This trend put a premium on knowledge of air handling, brought to the front in residential air con ditioning the warm air heating and sheet metal contractor with his experience in "treating" air at a centrabplace and get ting it properly distributed. It presented many new engineering problems, the solutions to which were undertaken by the warm air heating industry. In short, it put warm air heating in the center of residential air conditioning. In aiding to develop this' trend, assist in the solution of the problems involved, AMERICAN ARTISAN has provided a service to its field which has made it a recognized authority on residential air conditioning practice, read by the leaders in this business. . . It offers the manufacturers whose products are used in residential air con ditioning work coverage of the key factors. Such manufacturers will be interested in getting a copy of "Air Conditioning--A Simplified Outline of Its Markets." This study will be sent upon request. AMERICAN ARTISAN is published monthly. It is a member of the A.B.C. and A.B.P. Subscription rates--$2 00 per year; S3.00 for two years in V. S., Canada, Mexico, Central and South America. Foreign, $4.00 per year. Advertising rates furnished upon request. 982 Publications Heating, Piping and Air Conditioning Published by KEENEY PUBLISHING COMPANY 6 North Michigan Avenue, Chicago,. 111. eating, Piping H and Air Con ditioning is the publication which car ries in each issue the official Journal of the American Society of Heating and Venti lating Engineers in ad dition to its own regular editorial sec tion. The field of, this pub lication is that of in dustry and large com mercial and public buildings. Its editorial policy is to give specia lized attention to the design, installation, operation and maintenance of heating, piping and air conditioning systems in such plants and buildings. It circulates among consulting engineers and architects .... contractors .... and engineers in charge of heating, piping and air conditioning in industrial plants, large commercial and public buildings, federal, state and city governments, school boards and public-utilities. The entire membership of the American Society of Heating and Ventilating Engi neers is numbered among its subscribers, representing approximately 30 per cent of the total. Such a coverage means, for the adver tiser, consideration at all points in the selling of a heating, piping or air con ditioning product .... consideration in the selection of a product during the pre paration of plans and specifications; con sideration in the actual purchase of a product for installation; consideration in the year 'round buying of a product for operating and maintenance requirements. With the rapid development of air con ditioning, it has become evident that the air conditioning field has logically divided itself into two markets: (1) Industrial and Commercial; (2) Resi dential. These two markets are different in equip ment used; different in engineering problems involved; different in engineering, distribut ing and consuming per sonnel .... require, therefore, different sell ing jobs. To sell the [indus trial and large building field for air. condi . tioning, the manu facturer must' win acceptance from the engineers who design, specify, install, operate and select the system to meet the particular requirements of the plant or building. The system may be central, unit or "split," but .it is these engineers who are the influencing and purchasing factors. It is to such groups that Heating, Piping and Air Conditioning editorially caters--exclusively in the industrial and large building field. Without waste, the manufacturer of air conditioning products and accessory equipment, such as motors, drives, controls, etc., can reach through its pages those from whom he is seeking the necessary engineering acceptance. These facts are clearly outlined in a folder which will be sent to interested parties--"Air Conditioning--A Simplified Outline of Its Markets." Heating, Piping and Air Condition ing is a member of the A.B.C. and A.B.P. Subscription rates--$2.00 per year; $3.00 for two years in U. S., Canada, Mexico, Central and South America. Foreign, $4.00 per year. . Advertising rates furnished upon request. 983 Publications Automatic Heat and Air Conditioning 1900 Prairie Avenue Chicago Domestic Engineering 1900 Prairie Avenue Chicago Publications ealers in D automatic heating and air-conditioning equipment come from many indus tries. To reach these dealers of automatic heating and air conditioning equipment, manu facturers may choose of two ways. One is the long way around and is far more expensive. The other is the direct way and, of course, the eco nomical way. Choosing the first way the manufacturer must use space in the various publications, each reaching particular segments of the automatic heating and air conditioning industry--an expenditure in each pub lication. Choosing the second way the manu facturer may use space in Automatic Heat and Air Conditioning, the publication designed to blanket the entire industry, the direct and economical way. Your message in the pages of A ulomalic Heat and Air Conditioning reaches those dealers who are actively engaged in selling automatic heating and air conditioning equipment and specialties.. This includes specialty dealers primarily interested in electric appliances, including radios, wash ing machines, etc.,, heating dealers, coal dealers, electrical contractors, oil dealers, refrigerator dealers, hardware dealers, automobile and accessory dealers, etc., who have taken on the sale of automatic heating and air conditioning equipment. Whether or not you obtain your share of business from the automatic heating and air conditioning field depends upon whether or not you have proper access to desirable, poten tial dealers. The economical and ef fective way of doing this is by placing your story in Auto matic Heat and Air Conditioning. Business analysis of the readers of A utomatic Heat and Air Conditioning based on December . Issue 1934: Automatic Heat and Air Condition ing Dealers and En gineers.............. 8552 While some of these dealers were formed primarily to sell oil burners, room coolers or some other type of automatic heat and air conditioning, the big majority were primarily selling some related line such as steam and hot water heating, warm air heating, electric appliances, refrigerators, etc. Less than 24 per cent of the total comes from any single one of these groups. They are in reality specialty dealers handling more than one line. Consulting Engineers------------------- 53 Manufacturers and representa tives of manufacturers of automatic heat and air conditioning equipment 1,324 Utilities................................................. 48 Inspectors.....J...........-...... ~............. 54 Advertisers............. ...........................- 50 Advertising Agencies........................ 338 Office, file and men........................... 100 Total Circulation..,......... ............. :... 10,519 984 D,'OMESTIC ENGINEERING covers the contract ing and merchan dising phases of the plumbing and steam, vapor, vacu um and hot water heating, oil burner, gas burner, stoker and air condition ing field. It con centrates primarily on the technical and mechanical de velopments, mer chandising ideas, office and shop methods and news. The men on the staff of Domestic Engineering have a total of over 200 years of experience in the plumbing and heating field. They have been in at the birth of new products and the inception of marketing plans for them; they have sat in at marketing councils where their advice was effective in securing new sales, volume. Experience gives a background to Domestic Engineering for which there is no substitute. It shows itself in such obvious ways as files packed with' marketing data and in the adequate satisfaction of reader needs. Since its inception in 1889, Domestic Engineering's first consideration--and last --has always been for its readers. Its staff has spared no effort in its endeavor to help these readers; to keep them informed on all of the latest developments in their industry; to provide a wealth of technical information direct from the pens of the leading authorities in the field; to solve for them the many difficult problems which arise in their work and to supply them with all of the important news of their industry, while it is news. In.addition'. Domestic Engi neering maintains a Readers' Service De- partment. As its title implies, it is the function of this department to fur nish accurate, re liable information, at no cost to its readers, on various subjects pertaining to their particular business. Through this department the readers ' problems are analyzed and clarified. Engineers, thoroughly familiar with the field and its problems, offer readers dependable answers to all questions of a technical nature. Merchandising experts, with years of practical training to their credit, assist these men in formu lating merchandising plans, preparing mailing pieces and direct mail letters. From this department they may also obtain reliable buying information. Names and addresses of manufacturers of equip ment used in this field are available on short notice. Product information, too, may be had by the reader. Time and again this service has worked to the mutual advantage of both dealer and manu facturer; the dealer is put in touch with a trustworthy product and the manu facturer secures a reliable dealer. The leadership of Domestic Engineering in its field, earned by its service to its readers and by its long established, aggres sive editorial policy, has been responsible for attracting as its readers the active business builders in the industry. This same leadership has attracted to its pages the advertising messages of many of the leading manufacturers in the industry. 985 .' It Publications FUEL OIL ^Journal/ Published Monthly at 420 Madison Avenue New York As early as 1931 over 35 per cent of oilburner installation contracts included orders for additional heating accessories. In 1935 almost 23 per cent of the more than 154,000 conversion burners sold were installed with new boilers. An oilheating dealer thinks of an auto matic heating system as a good oilburner, using good fueloil, firing a good.heating system. All three are essential. The oil heating dealer needs information on all three subjects--oilburners, fueloil, heating systems. That's how Fueloil Journal is published. Every issue is soundly balanced against the dealer's working needs for information on all three subjects --heating, burners, fueloil. It is thus balanced editorially, with its circulation: Power oilburner dealers and dis tributors.............................. 9,739 Key heating contractors, plumbing , and heating contractors and engi- `' neers.................................................. 2,108 Fueloil distributors, selling fueloil and range oil...................................... 3,177 Accessory and heating and plumb ing supply distributors.................... 691 Total Dealers and Distributors.........15,715 Collateral Services Available to Advertisers Key Market Studies. Oilheating and Airconditioning Merchandising News. Annual Survey of the Oilheating Industry. Specific Product Surveys. Oilburner and Fueloil Specifica tion Chart. Power oilburner manufacturers and their executives................. 459 Accessory manufacturers......... 332 Rangeburner manufacturers...-. 173 Total Manufacturers...... ........ ''964 Total Dealers, Manufacturers 97 percent of total circulation 16,679 Architects, research laboratoriesand libraries..................... 117 Advertisers, agencies and com plimentary................... i............. 248 _ Miscellaneous.--.............................. 139 504 Grand Total................................... 17,183 The oilheating market is hitting new high levels in both unit and dollar volume. Heating equipment advertisers long, have found Fueloil Journal's advertising a profitable sales investment. It is worth your investigating. 986 Publications HEATING 6 VENTILATING sr AIR CONDITIONING THE INDUSTRIAL PRESS -- Publishers 140-148 Lafayette St. New York, N. Y. HEATING 6--' VENTILATING H EATING . ^. AIR CONDITIONING ence data appear in AND VENTILAT every issue. Re ING reaches the ports of meetings, "key men" of the industry--the engi neers, contractors and manufacturers who have the final word in the specific ation, installation, production and maintenance of the mechanical equip ment utilized in the heating, ventilating the activities of manufacturers, ab stracts of current papers, books and pamphlets, and-editorials on the plan ning, installation and operation of heating, ventilating and air condition ing systems in pub and air conditioning lic buildings, offices, fields. factories, schools, An editorial pro hospitals and homes gram of outstanding are other contents alertness-and au of continuous in thority is directed terest. by qualified heating and ventilating engi Air conditioning, now coming into its neers. A section devoted to moderniza own, has had a champion in HEATING tion, inaugurated in 1934, typifies the AND VENTILATING since 1904 when, forward-looking policy that has character in its very first issue, an article, on this ized the publication since its inception in then infant industry appeared. Since that 1904. News, trends, developments, per time, for more than thirty years, HEAT sonalities--every side of this important ING AND VENTILATING has con industry is faithfully and authoritatively sistently published the news and develop reported in this outstanding publication. ments of air conditioning up to its present There is a regular section devoted to new equipment, profusely illustrated and com prehensively reported. Degree-days and unit fuel consumption for various large cities in the country has been a regular monthly feature of the publication for seven years. The weather in large cities in typical localities of the country is high state of perfection and its pages have carried an impressive total of editorial lineage on this subject. Subscriptions to HEATING AND VENTILATING are $2.00 a year. Ad vertising rate cards, sample copies and market data will be gladly submitted on accurately charted. Two pages of refer receipt of application. 987 Publications Air fonditioninq Combined with (JilHeat Published by . HEATING JOURNALS, INC. 167 Madison Avenue New York, N. Y. T1. O the manufacturer wishing to reach the air-conditioning field in all its phases, OIL HEAT, with which recently has been combined AIR CONDITIONING with Fluid Fuels, offers great opportunities as an advertising medium. Its editorial con tent, initially devoted to the oil-burner industry alone, has broadened with the wider interests of its readers, presenting a useful and inspirational content suited to the wider field of operation. AIR CONDITIONING'S editors are widely known in the field for their fairness and knowledge and their unselfish service. They have made the editorial content valuable to the manufacturer, dealer, salesman and service man, by combining technical articles, with merchandising information. As a member of Controlled Circulation Audit, AIR CONDITIONING presents bi-annual statements covering its circu lation. The last statement shows its distribution to be: Dealers,*...............................................12,082 Manufacturers, burner....... ;......... 429 Manufacturers, air-conditioning ' and accessory............. .............. -- 395 Manufacturing executives------------ 166 Branch offices______ _________ Miscellaneous............................ 60 32 In addition, AIR CONDITIONING is sent on a rotational basis to 6,000 selected prospective dealers as follows: Heating contractors.-....................... 2,000 Electrical contractors...... ................. 1,000 Fuel dealers.................. 2,000 Specialty dealers and -public utilities.--............ ............................ 1,000 Each name on this rotational list is . selected on the basis of (a) location in known market, (6) credit rating, (c) organization and facilities for selling and installing air-conditioning equipment. *A recent individual survey of readers shows the following pertinent facts: Of the 12,082 rated as dealers, 42% are hand ling winter air-conditioning equipment; 36% summer air-conditioning equipment and 30% complete air-conditioning equip ment, while 69% handle boilers, 62% fur naces and 24% stokers. 100% ^handle oil-burners. These percentages, of course, are overlapping. The total distribution is 16,500 copies per month. Advertisers get excellent results due to this complete coverage, keen reader interest and responsiveness of the readers. Advertising is low cost--and produces direct business while building good will. "We have been decidedly pleased with the results obtained since we started to use your publication this year. Your cooperative attitude also has been appreciated very much." . . , O. A. Reiter, Hotstream Heater Company, Cleveland, Ohio. August 9, 1935. . (More than 50 inquiries from.a quarterpage ad in one issue.) 988 Publications Plumbing and Heating Trade Journal Published by PLUMBERS TRADE JOURNAL PUB. GO. 515 Madison Ave., New York City PLUMBING and Heating Trade Journal is edited to furnish a wellrounded, efficient service to the men engaged in the plumbing, heating, venti lating and air conditioning fields. To this end, it covers both the technical and business phases of their work, as well as many minor but exceed ingly important ones. It gives free technical service through a staff of practical engineers; expert merchandising assistance, and its technical and business articles are by men of recognized competence. Thousands of readers come to THE JOURNAL each year for solutions to their technical problems and while some of the questions and answers are published in the Readers' Technical Service section in each issue of the magazine, the vast majority of them--having to do with practically every phase of heating, ventilating and air conditioning-as well as plumbing--are answered by mail, because most of the requests for help are urgent and a delay in answering would, in some cases, entail actual monetary loss to the contractor. The Readers' Technical Service Depart ment of THE JOURNAL is staffed by editors who have spent their lives in the business; men who were successful plumb ing, heating, ventilating and air con ditioning engineers before they wrote a line for publication, and who now devote their entire time to keeping abreast of the field's technical developments and using their knowledge and experience for the benefit of JOURNAL subscribers. The technical service. rendered its readers by THE JOURNAL is closely paralled by what it strives to do for them in a business way, for it also publishes many authoritative articles on and answers questions concerning the various ramifications of business management and prints as part of every issue, a special section devoted to selling. One associate editor spends his entire time in the field writing articles on. the business man agement problems of JOURNAL readers, and the practical solution of those problems. Supplementing the busi ness and technical articles is a large amount of exclusive, staffgathered news that high-lights the back ground of the trade's activities. This news background is vital. It com pletes the industrial picture for the reader. It keeps him in intimate touch with what the various important associations and his fellow members of the craft are doing, throughout the nation and it charts the trends that are likely to have a very definite influence on the future operation of his business. THE JOURNAL editorial department draws its news from over a hundred trained correspondents located at strategic points throughout the country--by far the largest group of exclusively editorial workers used by any paper in the industry. It is this combination of the technical, business and news aspects of the industry that enables THE JOURNAL to achieve a finely balanced magazine that gives the reader the type of information he wants and needs, in brief, compact, time-saving form. THE JOURNAL is a member of the A. B. C., costs $2.00 per year by subscrip tion and has the largest paid circulation in the heating field. Sheet Metal Worker 45 West 45th Street New York Publications HEET METAL S WORKER, estab lished 1874--the oldest publication in the field --is published for the owners of shops in the sheet metal, warm-air heating and air-con ditioning field. These key men do or control a high percentage of the buying. Their shops may generally be divided into three classifications; sheet metal shops, heating shops, and combina tion shops. The ex clusive heating or sheet metal shops are located in the larger cities; elsewhere com bination shops will be found doing a general sheet metal and furnace heating business so that they may operate profit ably the year 'round. A large, exclusive sheet metal shop does a wide variety of sheet metal work for commercial, industrial, institutional, Fed eral and factory buildings, such as venti lation and air-conditioning work, roofing, skylights, blow pipe including dust arrest-, ing and air handling systems, etc. The exclusive heating contractor, handles residential, commercial, industrial, church, school and factory heating--gravity warmair furnace installation and forced-air systems equipped with fans, filters, auto matic humidifiers, air-washers and various types of controls. They also sell automatic stokers and oil burners. Essentially every furnace dealer is also a sheet metal con tractor as he owns and uses machinery and tools for making ducts, fittings, etc., for heating systems. The combination shop, which predominates in the field, handles all kinds of sheet metal and heating work. Editorially, Sheet Metal Worker is divided into two sections; the first half devoted to sheet metal and general prob lems of the industry; the second part entitled, Modernized Heating, Air Con ditioning and Merchandising, dealing ex clusively with these subjects. Its editorial scope is shown by its annual index which reveals an almost endless variety of data, listqd under fifty major subject classifica tions. Daily cor respondence, however, reflects an even wider conception of the needs of the industry, the members of which, by the thousands, bave called on the editors to solve their problems. In. addition to being the longest established publication in the field, its editorial and adver tising staff are likewise seniors, having been identified with it from 15 to 26 years. Its editor-in-chief, Edwin A. Scott, is regarded as an outstanding authority on trade practice and merchan dising methods, and has participated in furthering many of the outstanding move ments of the industry. The Edwin A. Scott Publishing Co. is the largest pub lisher in the world of books devoted to sheet metal, heating and allied subjects. Sheet Metal Worker enjoys unusual reader interest and the confidence, of thousands of substantial dealers and con tractors throughout the country because of the high calibre of its editorial content. Its prestige and leadership is also recogni zed by prominent manufacturers in all lines, who use its advertising pages--many of them exclusively in this field--with profitable results. , Two of its present advertisers have used space in it con tinuously for over 60 years and others over half a century. Because of long experience and close contact with the sheet metal and warm-air heating industry, the Sheet Metal Worker organization is.well equipped to consult with manufacturers regarding sales, merchandising and advertising pro grams. A cordial invitation, without obligation, is extended to all manu facturers to take advantage of this valuable service. Annual subscription rates--$2.00 per year. United States and Mexico; in Canada, $2.50; Foreign, $3.00. Advertising Rates Furnished on Request. Pumps American Steam Pump Company Plant and General Offices: Battle Creek, Michigan Direct Factort Branch: 17 Battery Place, New York City Sales and Service Agencies Throughout the World PRODUCTS AND SERVICE--This Com pany, organized 1873, offers a complete line of centrifugal, steam and power driven pumps. Your inquiry for de scriptive bulletins or specific recommenda tion is invited. REDI-VAC HEAT ING PUMPS--An im proved outfit. Removes air and condensation from return lines, dis charging air to atmos phere and water to boiler, both functions automatically con trolled. Bronze fitted throughout. No close clearances to wear rapidly, or "freeze up" during idle season--an important advantage over other types, practically eliminating periodic service expense. RECIPROCATING VACUUM HEATING PUMPS--Time-tested design and construction. Standard equipment in cludes bronze fittings throughout. Motor driven, if desired. (We also build simplex and duplex steam pumps for boiler feed, etc.) Redi-Vac Hen!ing Pump Redi-Retum Condensation Unit Centrifugal Pump REDI-RETURN CONDENSATION UNITS--Compact, de pendable and exception ally low priced. De signed to collect and pump back to the boiler returns from high and low pressure heating sys tems, handling water at 210F. Furnished com plete as shown with full automatic control. Twin units can be furnished. Large range of sizes. MOTOR-UNIT CENTRIFUGAL PUMPS -- Simple and inexpensive, ideal for air washer and cooling work, pumping clear water or brines. Pump attached directly to motor. Bearings, base and coupling eliminated. Only one stuffing box. Very compact. Fifteen sizes; 5 to over 500 g.p.m. BALL BEARING CENTRIFUGAL PUMPS--Single-stage, horizontally split-case type with deep. groove ball bearings, stainless steel shaft and bronze seal rings. High ef ficiencies insure low operating cost. (We also build multi-stage centri fugal pumps.) Reciprocating Vacuum Seating Pump 991 Ball Bearing Centrifugal Pump Pumps Chicago Pump Company SEWAGE - CONDENSATION - CIRCULATING BILGE - FIRE - HOUSE - VACUUM 2330 Wolfram Street BRUnswlck 4110 Chicago PRODUCTS--Return Line Vacuum Heating and Boiler Feed Pumps, Con densation, House, Booster, Fire Pumps, Circulating, Brine, Sewage, Bilge, Sludge, Pneumatic and Tankless Water Supply Systems and Automatic Alternator. Condensation Pump and Receiver for Low, Medium and High Pressures Systems up to 150,000 Sq. Ft. Radiation "Sure-Return" Condensation Pump for Low and Medium Pressure, and Systems . . up to 35,000 Sq. Ft. Radiation Fig. 1946 Pig. 1931--F. C. Condensation Pump "Chicago" Condensation Pumps are built for systems ranging from 2,000 up to 150,000 sq ft of radiation, and for boiler pressures up to 200 lb. Units are built in either single or duplex--the duplex being alternated in their operation by the Automatic Alternator. For tables and com plete description ask for Bulletin 129. Vertical Condensation Pump for Low and Medium Pressure for Systems up to 100,000 Sq. Ft. Radiation , Fig. 1940 Vertical ' Condensation Pump The vertical condensation pump is designed to re ceive returns from lowest radiation. The receiver is placed underground--an ordinary' hole sufficing if necessary -- and requires very little floor space. Unit is shipped complete, easy to install, assembled so as to prevent steam leaks. Special bearings will stand up under hot water for several years. A special float mechanism is guaranteed not to leak or stick in stuffing box. Complete data and descrip tion in Bulletin 1S3. ' "Sure Return" Condensation Pumps and Receivers are built for systems up to 35,000 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 Auto matic Alternator. Complete data in Bulle tin 181. Horizontally Split Pumps for all Services Fig. 1881--Single Stage Type "D" Pump For any service (such as boiler feed, water supply, tank filling, circulating, fire pro tection, etc.). Chicago Pump Co. builds a line of horizontally split case centrifugal pumps in both single and multistages. Completely bronze fitted (except where special fittings are required) ball bearings, internalwaterseal,oilisfiltered. "Chicago" Horizontal Pumps are built for efficient performance and long life. 992 Chicago Pump Company Pumps "CONDO-VAC" Return Line Vacuum Heating and Boiler Feed Pumps Automatic Alternator is available on Duplex Return Line Vacuum Heating and Boiler Feed Pumps Fig. 2102--Duplex "Condo-Vacs" with Duplex Double Automatic Control Sewage Ejectors Fig. Si00--single "Condo-Vac" No vacuum on stuffing boxes, ample clear ance in rotating member. It costs less to operate a Condo-Vac. Condo-Vac reduces corrosion in piping and boiler to minimum --because pump does not take in air from atmosphere and entirely eliminates ail air coming back from system. Condo-Vac is quiet, has a low inlet, entirely automatic, fool-proof, easy to maintain. Ask for Bulletin 137, learn more about the modern vacuum pump with the long life principle of operation. Close-Coupled Pumps Boiler Feed. Circulating, Tank Filling, Water Supply Fig. 5087--Duplex Non-Clog Sewage Ejectors with complete control equipment mounted on basin coter. "Automatic Alternator" transfers operation from one pump to the other Fig. 2130--Cloee-CoupUd, side suction pump. Capacities range from 3 to 600 0. P. M. against heads up to 189 ft. Motors fromtlB to 20 Hp. Discharge 1 to 3 in. Both closed and open type impellers 993 Pumps The Nash Engineering Company South Norwalk, Conn., U. S. A. Sales and Service Offices in all Principal Cities Centrifugal Pump Made in standard and suction (self-priming) types. For circulating hot and cold water; boosting city water pressure; handling water in air washing and conditioning; handling ash sluicing water, etc. Compact--motor armature and pump im peller are mounted on the same shaft. Simp lified--no bearings in pump casing, one stuf fing box. Accessible--impeller removable without disturbing piping or shaft alignment. " Self-priming types will handle air or gas con tinuously with liquid being pumped, and can be operated intermittently without foot valve. Supplied in 1)4, 1J4, 2, 3, 4, 6, and 8 in. sizes with capacity up to 2000 g.p.m. Heads up to 300 ft. Complete data in Bulletin No. 155 on request. Suction Sump and Sewage Pumps Jennings Suction Sump Pumps are self priming centrifugals for handling seepage water and liquids reasonably free from solids. The Suction Sewage Pumps are equipped with a non-clog type impeller for liquids containing solids. . Suction piping only is submerged. Centrifugal impeller and vacuum priming rotor are both mounted on same shaft that carries rotor of the driving motor, forming a single moving element and rotating without metallic contact. These pumps will handle air or gas with liquid being pumped, and because of self priming feature are installed entirely outside of pit. This affords perfect accessibility for inspection or cleaning. Capacities to meet all requirements. Complete data in Bulletins 169, 161 and 188 on request. . Air Compressor and Vacuum Pump The Nash Air Compressor operates on a unique and different principle. The one moving part rotates in casing without metallic contact. There are no valves, pistons, or sliding metal vanes. There, is nothing to wear, and no internal lubrication. Nash Compressors deliver absolutely clean.air. Unit illustrated is built integral with elec tric motor. Compact, may be installed any where. Ideal .general service compressor. Suitable for priming pumps bn water systems, handling CO* gas, agitation of liquids, as blood sucking pumps in hospitals, etc. Pressure 75 lb. or vacuum 28 in. of mercury. Equipment furnished for any capacity. Complete data in Bulletin No. 192 on request. 994 \ Pumps The Nash Engineering Company South Norwalk, Conn., U. S. A. Sales and Service Offices In all Principal Cities Jennings Return Line Vacuum Heating Pumps Standard with the heating industry for over sixteen years. They remove air and con densation from the return lines of vacuum steam heating systems, discharging the-air to atmosphere and returning the 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. The pump is bronze fitted throughout. Supplied either direct connected to standard electric motors, for belt drive, or for steam turbine drive. For continuous or automatic operation against pressures up to 40 lbs. Sup plied standard in .capacities up to 300,000 sq. ft. E.D.R. Complete data in Bulletin No. 85 on request. Jennings Vapor Turbine Vacuum Heating Pumps The Jennings Vapor Turbine Heating Pump combines all of the advantages of the standard return line heating pumps with a new type of drive, a specially designed low pressure tur bine which operates directly 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' practically no heat loss. This pump affords the safety and economy which goes with a continuous condensation return and steady vacuum, and at no cost for electric current. Furnished standard in capacities up to 65,000 sq. ft. E.D.R. Over 65,000 sq. ft. and up to 150,000 sq. ft, infor mation will be furnished upon request. Complete data in Bulletin No. 208 on request. Condensation Pump and Receiver Removes condensation from' radiators in return line steam heating systems and pumps condensation back to the boiler. They are sturdy and compact in construc tion, and combine receiving tank, pump and driving motor in a single assembly. Bronze fitted throughout, with Tobin bronze shaft. Impeller is of special design adapted to hand ling hot water with highest efficiency. Jennings Condensation Pumps are fur nished in standard sizes with capacities ranging from 1)4 to 225 g.p.m. of water. For serving from 1,000 up to 150,000 sq. ft. of equivalent direct radiation. Complete data in Bulletin No. 165 on request. 995 Pumps 0JMS PUMPS Decatur Pump Company Decatur, 111. BMS PUMPS Qzdy ooo Bttrtiofpart BURKS SUPER TURBINE PUMPS AND WATER SYSTEMS Series 1100 Burks Super-Turbine Pumps . Fully Self-Priming. A Heavy-Duty Pump adapted for general use with Water Systems, Condensation units, Circulating Systems, Booster Work, and will also handle effectively many other pumping requirements. Suction lift 28 feet at normal altitudes. BURKS CONDENSATION RETURN UNITS Fully Self-Priming Will Not Steambind Construction Features Ability to pump air alone, or air mixed with water, to the full pressure rating of the pump, means that the Burks pump will not steambind. Pump capacities range from 150 gph to 1,000 gph against boiler pressures up to 100 lbs per square inch, and will take care of up to 12,000 sq. ft., of radiation per unit. Only one moving part--the impeller-- and this one part does not contact with metal at any stage of operation. Self-priming and fully automatic. Im peller and raceway of cast bronze. Shaft of stainless, non-corroding steel, and carried in over size ball bearings. Hydraulically Balanced These pumps are hy draulically balanced and cannot be made to pound or hammer under any condition of operation. Series 4700 Condensation Return Unit Self priming high head units have high efficiency. They are of open-impeller type. Self priming Centri fugal pumps that are different! Capacities to 400 gpm- Built up to an engineering ideal. Series 41100 Condensation Return Unit -? Burks Self Priming Centrifugal Pumps Series 1400 996 Pumps The John H. McGowan Company General Offices: 54-58 Central Avenue Cincinnati, Ohio CENTRIFUGAL-STEAM AND POWER DRIVEN-TYPES FOR WIDE RANGES OF APPLICATION Side Suction Type Double Suction Split Case Type . Centrifugal Pumps All units embraced in the various groups of this type may be furnished for stated capacities and heads and equipped with any suitable type of drive desired. Side Suction--Single Stage--Capacities 5 to 125 gpm for heads up to 70 ft. Double Suction--Split Case Single Stage--30 to 3500 gpm for heads 10 to 131 ft. Multi-Stage--Split Case Single or Double Suction according to capacity and head, 30 to 3500 gpm for heads up to 1500 ft. Condensate Return Units--Horizontal Pump and Receiver, Motor Driven for 1000 to 100,000 sq ft radiation and return pressures from 10 to 150 lb. Vertical Type for 3000 to 100,000 sq ft radiation and for return pressure from 10 to 50 lb. Vertical Sump Pumps--Single and Duplex for capacities from 10 to 500 gpm and for heads up to 108 ft. Single Steam Driven Pumps Vacuum Pumps for radiation up to 190,000 sq ft. Condensate Pumps and Receivers for return pressure up to 200 lb. Boiler Feed Pumps--In Piston and End Packed Plunger Types for Boilers of 100 to 1300 hp and for pressures up to 200 lb. Circulating Pumps--For capacities up to 350 gpm. Duplex Steam Driven Pumps Boiler Feed Pumps--For 200 lb pressure include Packed Piston and Center Packed Plunger type for Boilers up to 3000 hp. End Packed Pot Valve Pumps 300 lb pressure patterns for boilers up to 3000 hp. Vertical Condensate PumP and Receiver Single Steam Driven Vacuum Pump Duplex ' Condensate Pump and Receiver Fuel Oil Heater Sets with Duplex PumPs Single Steam Driven Boiler Feed or Circulating Pumps For 7000 to 95,000 sq ft ra diation and for return pressure up to 200 lb. Single Sets or Duplex Sets for Boiler rating up to 9000 hp. Duplex Boiler Feed or Circulating Pumps All pumps fully guaranteed for service applying to sale when properly installed 997 Pumps Westco Pump Corporation 6 Gaines Street, Davenport, Iowa Branches: New York, Philadelphia, Chicaco, San Francisco and Los Angeles. Representatives in 100 Principal Cities ' PRODUCTS--Single-Stage, Double-Suction Turbine Pumps for low or high head duty; Condensation Pumps and Receivers; Double-Suction, Self-Priming Turbine Pumps; Turbine Pumps with Gasoline Engine Drive; Automatic Water Systems; Refrigerating Pumps for Brine or Water Circulation; Under writers' Laboratory-Approved Tank Filling Pumps for Sprinkler, Gravity and Pressure Tank Supply; Deep-Well Turbine Pumps. models available. Sizes 5 to 90 gpm against heads up to 150 ft. Showing Pump Casings, patented Remoeable Liners and Westco'e only moving part--the Impeller which operates without metal-to-metal contact PATENTED REMOVABLE LINERS form the liquid channel wherein the Im peller rotates. Advantages are: 1. Life time service from pump casings because all surfaces subject to wear or deteriora tion are incorporated in Liners which can, if necessary, be replaced at low cost. 2. Interchangeability of Liners permits easy, quick variation of pump capacity and head. 3. Extra Liner-Impeller sets car ried on hand furnish stand-by pump pro tection at about usual cost. Double-suction Intake creates perfect hydraulic balance. Capacity not affected by considerable fluctuation of head. Direct motor driven. Westco Uni-Bill Turbine Pump Certified blueprints, specifications, catalogs containing performance and selection tables gladly sent on re quest. When requesting prices give: 1. Specific gravity and kind of liquid, 2. Gallons per minute, 3. Head in ft. or pressure in lbs., 4. Source of supply, 5. Power available. Westco Standard Type BR Pump STANDARD WESTCOS for water suply, brine and drinking water circulation, oiler feed, etc. Furnished in cast-iron, bronze-fitted or all bronze. Sizes S to 400 gpm against heads up to 1000 ft. WESTCO UNI-BILT PUMPS for small capacity, high or low head duties. Es pecially designed for Air Conditioning and Refrigerating applications. Self-priming WESTCO CONDENSATION UNITS operate efficiently against 50 per cent variations (up or down) in head. Handles reasonable volumes of steam or air. Easy to clean. Extremely compact. Quiet. Sizes for service on layouts with 1000 to 50,000 sq ft radiation surface, requiring from 4 to 400 gpm against heads up to 1000 ft. Radiators, Copper dt Waterbury Chase Brass & Copper Co Incorporated Subsid'ary of Kennecott Copper Corporation Heating Products Division A Connecticut CHASE COPPER CONVECTORS Concealed or Standard Cabinet Styles For Hot Water or Steam Heating Systems Advantages: 1. Made with copper tube and copper fins. Copper is the best commercially practicable material known for transferring heat. 2. The copper tubes are firmly secured to the headers by brass compression nuts, a universally accepted method of making a permanent bond not affected by strain or stress. The copper fins are corrugated to provide enlarged area for a given depth of unit and to increase strength and rigidity. 3. The copper supply tubes are % in. in diameter, which insures a sufficient steam or water-way to meet all service conditions. 4. High heat output in proportion to the space required and to the weight of the radiator. 5. A copper to copper contact between fins resulting in high heat conductivity. 6. No heat resisting solder used. 7. Chase convector ratings are convector manufacturers certified ratings. They are conservative and guaranteed. '- Design of Chase Convector The fins where they contact the tubes, have a flange or lip, which acts as a definite spacer for the fins. Part of the lips are lapped over and under each other, somewhat like shingles on a roof. These laps prevent slipping and insure a tighter bond on the tube. An intimate and permanent copper to copper bond between fins and tubes is accomplished by a patented process of forcing the tubes and the overlapped fin flanges from round to octagon shape. No solder is used. '. Chase Copper Radiators are made in a number of sizes and styles to meet the varying conditions of building construction. CHASE BRASS AND COPPER WATER HEATERS Chase brass and copper indirect water heaters are conservatively rated. Being made entirely of rustproof brass and copper, as the name implies, they are less subject to an accumulation of water impurities and consequently last longer. An outstanding'feature of the Chase brass and copper water heater is that steam at a high pressure may be run through the coils, and water pressure up to 35 lb can be handled through the shell without difficulty. ' For Complete literature on Heating Products, write Chase at 2 Harris St., Waterbury, Conn. See also Pages 974 and 975 999 Radiators UTICfl HODIHTDH CDRPDPHTIDN Utich, N.Y THE UTICA CAST-IRON CONVECTOR The Utica Convector is designed for installation within enclosures and to heat effectively by convection. The cored section is ample to assure good circulation and rapid air elimination. The widely spaced fins, integrally cast, will not clog and offer minimum resistance to air flow. . Utica Convectors will perform equally well on steam, vapor, vacuum and hot water systems. They are simple in construction, durable and efficient. The Utica Convector Made in 3% in., 5% in., 7% in., and 9% in. widths and in any length above 18 in. in multiples of 5 in. UTICA REDSQUARE BOILERS are stream line in ap pearance and scien tifically designed for efficiency and fuel economy. The 17 Series will carry from 200 to 740 sq ft steam radiation and 330 to 1230 sq ft of water radiation. The 25 Series will carry from 620 to 1240 sq ft of steam radiation and 990 to 1990 sq ft of water radiation. Also available in oil burning types with ex tended jacket. i 7 Series Redsquare Boiler 5 Series Redsquare Boiler. Humid-Heet Radiator The HUMID-HEET Radiator furnishes the required amount of radiator heat--and replenishes the air with moisture. Made in a wide range of sizes. Midget Radiators Cut-away view of Humid-IIeel Radiator showing porcelain enameled, water wells Midget Radiators--Due to their narrow width (2-tube, 3H in., 3tube, 4.% in.) and sections 1)4 in. center to center, occupy one-third less space than standard tube radiators. 8-Tube Midget . *n' wide Also Manufacturers of Standard Tube and Wall Radiators 1000 Registers and Grilles The Auer Register Co. 3608 Payne Avenue, Cleveland, Ohio Manufacturers of Registers and Grilles for Gravity and Air Conditioning Systems; Wrought Metal Grilles for Concealing and Protecting Radiation AIR CONDITIONING REGISTERS AND GRILLES Auer Registers and Grilles for Air Conditioning have been designed to meet all modem requirements--appearance, practicability, and simplicity in installation and operation. They are made in various designs to harmonize with modern interiors. Constructed and tested to operate with high efficiency in any system of forced air, they are a departure, not merely an adaptation, from gravity registers. They are designed for easy installation in either new construction or remodelling. No. 2030 Sidewall The design shown is our standard design, termed Classic. It is very adap table to most interiors; other designs, however, can be furnished. This type is made with a band frame and is installed after plastering. It is ideal for new construction or remodelling. Without a valve it is used as a return. No. 2230C Sidewall This illustration shows register directing air in three directions. -V////I |\\\\\L It can be made to direct air in one direction only or in two directions. The directing air blades can be set at any angle specified. Installation can be made with band frame or sliding frame as shown in previous illustrations. No. 2010 Sidewall This type is used in new construction exclusively. The sliding frame is anchored to studdings before plastering. After plastering, the register is easily attached to the frame and can be slid to the position desired between the studs. - The same type furnished without a valve is used as a return. No. 2005 Oblong Auer Registers and Grilles can be fur nished in many designs. Auer Registers and Grilles can be furnished in any standard finish. Illustrated catalogue showing complete line of registers for all purposes and chart of open areas and capacities will be forwarded on request. 1001 Registers and Grilles Hart & Cooley Manufacturing Co. 61 W. Kinzie St., Chicago Factory: Holland, Mich. PRODUCTS Forced Air Registers - Warm Air Registers - Directional Grilles Stamped Grilles - Furnace and Damper Regulators - Pulleys - Chain A COMPLETE LINE OF FORCED-AIR REGISTERS FOR AIR CONDITIONING INSTALLATIONS No. 90 Directional Grille No. 90 Grille is made up of a number of thin strips, which are shaped into a series of grooves. The strips, when assembled, form an exceptionally attractive grille with openings ]/& in. wide and 1 in. in depth. The tubes formed by the grooves in the strips may be straight, at an angle of 45 deg. to the left or right, or up and down, or in any combination thereof, thus making it possible to secure positive control of the air flow in any desired direction. . Characteristics of No. 90 Grille 1. Concealment of Duct--The depth of the grille (1 in.), together with the tubular shape of the openings, result in exceptional concealment of the duct. 2. Dual Control of Air Flow--The air is controlled in two planes--horizontally as well as sideways. The air leaves the grille in a horizontal plane regardless of the approach. 3. Resistance--Directional flow is obtained by changing the path of the air gradually. The turbulence which would be caused by an abrupt change in the path' of the air is eliminated, thereby greatly reducing the resistance of the grille. 4. Noise--The elimination of turbulence likewise eliminates the greatest cause of noise in the grille. Velocities of 2000 ft. per minute or more may be used without adding to the noise level. 5. Air Capacity--The grille itself has a free area of approximately 89 per cent. When used with the 3-piece and 1-piece frames the free area is slightly reduced, owing to the clearance necessary for the frames. . Perforated Grilles In addition to No. 90 Directional Grille, the.four designs of Perforated Grilles shown below are available. These perforated grilles are easily decorated to match their sur roundings and result in a satisfactory installation in those cases where directional control of the air flow is not required. M.VV4AMA1 No. SO Design Grille No. 40 Design Grille 1002 Hart & Cooley Manufacturing Co. Registers and Grilles Six Types of Registers Available i All of the five grille designs shown on the preceding page are available with or without valves, and are likewise available with any of the six types of frames described below. i Sidewall Register with Streak-Proof Frame--Frame and stackhead are im bedded in plaster, resulting in streak-proof installation. Frame provides plaster lock, eliminating cracking of plaster. Sidewall Register with Band Iron Frame--Ideal for old house installations. Face has ample margin to cover opening in wall. Baseboard Register with StreakProof Frame--Stackhead is permanently secured to frame, eliminating streaking. Face is readily removable for cleaning or redecorating. Baseboard Register- with Intergal Frame and Face--Easy, to install--less expensive. Return Air. Intake--% in.- Pro jection--Designed for. use . where face extends above the top of the baseboard. No. SSS1--Sidewall Register Showing Streak-Proo) Frame and Installation Return Air Intake--Flat--Designed for installations in which the baseboard height is greater than that of the intake. H & C Simplified Grille Selection System The H & C Simplified Grille Selection System is based on a series of charts which give complete information on air spread, velocity.required for various throws, minimum grille level required, resistance, and correct size of grille. A specimen chart is illustrated at the left. When used with the H & C Grille Selection Forms, these charts make it a simple matter to select the proper type and size of grille, and to determine all other information pertaining to the grille which is necessary to insure proper air distribution. . The full set of charts is shown in the new H & C Air Conditioning Register and Grille Catalog now' available upon re-, quest. The Grille. Selection Forms are likewise available without charge, in pads of 25. For either the Catalog or FOrms, apply, to your jobber or direct to this company. -T .' ; 1003 Registers and Grilles Tuttle & Bailey, Inc. Main Office and Factory New Britain, Conn. Branch Offices: Boston, New York, Chicago, Philadelphia PRODUCTS--Ornamental Grilles in Cast or Wrought Metals, Grilles and Registers for Heating, Ventilating and Air Conditioning, Air Control Devices, Convection Heaters. For complete information, write for Catalog No. 46 "Air Conditioning Grilles and Registers." AIRLINE GRILLE, No. 880 Airline Grille No. 880 Among the more popular grilles for Air Conditioning is the Airline Grille, No. 880. The core of this grille is designed to offer minimum resistance to air flow, and the construction, although rugged, presents a neat, attractive as well as sanitary ap pearance. The bars on the Airline grille may be set either vertically or horizontally to provide fixed air deflections. From one to five air streams may be directed from a single grille. Standard bar settings are straightandtodeflectair22and 42- SANTROLS The Santrol is a new control device designed for installation back of a grille in a horizontal duct. The individually ad justable two piece blades provide both volume control and uniform distribution of air over the entire face of the grille. Blades may be adjusted by hand before installation of the grille or afterwards by means of a wire inserted between the bars of the grille core. Proper installation of the Santrol requires a four inch deep collar projecting from the side of the duct. McKnight Register -with Airline Face \ VOLUME CONTROL McKNIGHT REGISTER The McKnight register is a.tested and proved device for easy control of air volume at the outlet. No dampers or diffusers are necessary on a McKnight installation as all of the control is accom plished with a key right at the register face, thus effecting a great saving of time in balancing a system. The McKnight register may be combined with an Airline design face to provide air deflection in addition to volume control. 1004 Tuttle & Bailey, Inc. Registers and Grilles Tuttle & Bailey, Inc. New Britain, Conn. CEILING OUTLETS The use of ceiling outlets as a means of supplying air on an air conditioning instal lation has become increasingly popular. Tuttle & Bailey have standardized on the round outlet combined with the Airline grille, although special outlets may be furnished; Manufacturing facilities for this item now make its cost a minor factor on any installation. Ceiling outlets are furnished in the standard sizes listed in the table below. Air volumes delivered at various velocities are also given. Round Ceiling Outlet Listed Size Diameter by Height 300 FPM 8*4' 12*4' 12*6' 18*4' 18*6' 24*4' 24*6' 24*8' " 181 271 407 408 612 540 810 1080 CFM Delivered at Following Air Velocities 500 FPM 302 452 678 680 1020 900 1350 1800 800 FPM 482 723 1085 1088 1628 1440 2160 2880 1000 FPM 602 904 1356 1360 2040 1800 2700 3600 1500 FPM ~ 905 1356 2034 2040 3060 2700 4050 . 5400 AIR CONDITIONING REGISTERS FOR SMALL HOUSE . CONSTRUCTION Included in the Tuttle & Bailey line are many styles of registers for air conditioning in both single and multiple valve con struction. There are six standard face designs all of which have been selected not only to provide beauty but also efficiency in operation. . Single valve registers are divided into two general classes--Sidewall or Base- . Three-piece Sidewall Register No. 8888 (Streakproofl board, depending on the location for which they are adapted.. Sidewall registers are made in three-piece, two-piece and one- piece constructions. No. 8784 BASEBOARD REGISTER INSTALLATION Baseboard registers are divided into two general classes--those designed to extend above the baseboard, and those designed to fit into the baseboard (see illustration). For complete information on air con ditioning registers, refer to Sec. I, Catalog No. 46. Baseboard Register' Installation Registers and Grilles Independent Register & Mfg. Co. Established 1898 3753 East 93rd Street, Cleveland, Ohio "FABRIKATED" FORCED AIR REGISTERS Reg. U. S. Pat. Office '1With `'Independent Adjustable Directed Air Flow Registers and Grilles the engineer is in complete control of the direction of air flow. No. SS1-A--Shotting a combination of Adjustments Showing the simple and easy method of adjustment. Each in terior grille bar is adjusted in dividually. The directional adjustment can be made at the time of installation and after the system is operating it may be easily changed at any time to make, cor rections to "meet unforeseen or changed conditions. The method of adjustment is very simple as shown, and many directions and combinations can be worked out, to suit the need. Adjusting tools are sent with each order. No. Sil-A--Air Flow Downward Adjustable from straight to 45 deg. Fine Mesh "FABRIKATED" Registers and Grilles Thinner grille bars set closer together than in the above adjustable type. ,ljli iy i ; `,.i :ii'i!li:i u'l. ' ii i iji 1 J1 11 ?WMif Miiliiipl In the Fine Mesh "Fabrikated" the Grille bars are not adjustably but are mounted at the time of manufacture, either for straight flow orMor the fixed angle of deflection, as specified by the engineer. No. St--Fine Mesh, fan like distribution Independent "Fabrikated" Fine Mesh Registers and Grilles'can" be furnished in nearly any size and with several different kinds of setting frames, and methods of mounting. No. Si--Fine Mesh New Independent Catalogs tell the complete story in every detail;--yours for the asking. 1006 Registers and Grilles The Waterloo Register Company Waterloo, Iowa Established 1902 Seattle, Wash. Pioneers in the Manufacture of Directional Air Conditioning Registers and Grilles FHG-045 Venetian Type Grille 20 Gauge Louvres Anchored at 46 Degrees {66 Per Cent Open Area) FHD-204 Venetian Type Baseboard (Register-Adjustable Louvres) (Waterloo) Vene tian Type Registers -- Provide almost complete masking of duct openings, yet permit ample free area. The smooth, attractive appear ance of the straight louvre effect is modern and up to date. WL Rod F-5103^ Wall Diffuser with Vee-U Frame and Adjustable Louvres (Waterloo) VeeU Frame-- Is a channel section of 20 gauge cold rolled steel that provides a plast er edge and flush set ting for wall registers. "V" gripper is opened to admit stack head flange, then clamped tightly shut,' strengthening entire stack as the frame is nailed to studding. "U" chamber allows for expansion and contraction from temperature changes and protects sur rounding plaster. (Waterloo) Adjustable Registers--Control direction of the air flow by operation of the louvres in sets. Five positions of directional settings are possible from full closed to full open. When operating lever is pushed back out of sight, it automatically locks the louvres. (Waterloo) Registers--Are furnished in all finishes in standard duct opening widths of 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, and 36 in. and standard heights of 4, 5, 6, 8, and 10 in. Odd sizes at slight extra cost. Louvres made from 20 and 24 gauge cold rolled steel and frames are of double thickness 18 gauge. Send for Complete Catalog No. 16. 1007 For Adjusting Horizontal Louvres Specialties, Heating Armstrong Machine Works 851 Maple Street Three Rivers, Mich. Exclusive Manufacturers of Armstrong Inverted-Bucket Steam Traps A R M S T R ONG Atlanta, Ga., J. M. Tull Metal &.Supply Co., Inc., 285 Marietta St., N.W. 'Baltimore, Md.vMilby & McKinney, 218 Water St. Birmingham, Ala., Southeastern Products Co., 1401 Lomb Ave.. . Boston, Mass., Files Steam Specialty Co., 261 Franklin St. Buffalo, N. Y., Herr Steam Specialty Co., 360 Warwick Ave. Charleston, W. Va., Baldwin Supply Co., 518 Capitol St. Chicago, 111., Barrett-Christie Co., 108-112 N. Clinton St. Dallas, Texas, Geo. B. Allan & Co., North Texas Bldg. Denver, Colo., Hendrie-Bolthofi Mfg. & Supply Co., 1637--17th St. Des Moines, Iowa, . B. Carr, 627 Insurance Exchange Bldg. Detroit, Mich., A. F. Squier, 2081 Blaine Ave. . Duluth, Minn., John E. Smith, 1721 W. Michigan St. Erie, Pa., Coblentz Equipment Co., 1119 Peach St^ Evansville, Ind., Evansville Supply Co., Esco Bldg. Fond du Lac, Wis., A. N. Goff, 94 Eighth St. Honolulu, T. H.,-The von Hamm-Young Co., Ltd. Indianapolis, Ind., Indiana Belting & Supply Co., 34 S. Capitol Ave. ' Kansas City, Mo., Hughes Machinery Co., 342 Mfrs. Exchange Bldg. Knoxville, Tenn., Leinart Engineering Co., 427 Walnut St. Los Angeles, Calif., Guy L'. Warden, 114 West 17th St. Louisville, Ky., Graft-Pelle Co., 116 N. Third St. Memphis, Tenn., The Power Equipment Co., 1352 Madison Ave. REPRESENTATIVES Milwaukee, Wis., Hamacher & Williams, 2540 W. Wells St. Minneapolis, Minn., Albert C. Price Co., 257 Fourth Ave. ` . Montreal, Quebec, Engineering Equip ment Co., Ltd.. 620 Cathcart St. New Orleans, La., Louisiana Steam Equipment Co., 109 Tchoupitoulas St. New York, N. Y., Advance Engineering Co., 69 Dey St. Philadelphia, Pa., Brogan & Co., 810 Race St. Phoenix, Ariz., John W. Ladlow, Box 1784. Pittsburgh, Pa., R. S. Eastman Co., 222 First Ave. Portland, Ore., J. C. Ross & Co., 917 S.W. Oak St. Richmond, Va., A. T. Shepherd, 411-12 Tenth St. Bldg. ' St. Louis, Mo., O'Brien Equipment Co., 2726 Locust Blvd. Salt Lake City, Utah, Mfrs. Sales & Service Co., 144 S. Fifth West St. San Francisco, Calif., Refrigerating & Power Specialities Co., 380 Brannon St. Seattle, Wash., J. C. Ross & Co., 2434 First . Ave. S. South Bend, Ind., Smith-Monroe Co., 1912 S. Main St. ' Spokane, Wash., R. A. Halstead. P. O. Box 1359. Syracuse, N. Y. The Hopton Co., 321 Denison . Bldg. Tampa, Fla., G. W. Neale, 504 E. LaFayette St. Toronto, Ont., Arthur S. Leitch Co., Ltd., 1123 Bay St. / Vancouver, B. C., General Equipment, Ltd., 410 Homer St. : Winnipeg, Man., Kipp-Kelly, Ltd., 68 Higgins Ave. ' Wooster, Ohio, Steam Economies Co., 1011 Beall Ave. Armstrong traps are offered in two types for heating service, "standard" traps and "blast" traps. Standard traps are used for drip headers and unit heaters where little air is to be handled. Where large volumes of air must be removed quickly the blast trap is available. The "Blast" . Type Trap--For fast handling of large quantities of air, the standard Armstrong trap can easily be furnished as a " blast " type trap by the use of a thermic bucket. The air handling capacity of this bucket is approximately 100 times as great as with the regular air vent. As long as the trap is cold a large vent in the top of this bucket remains open, and it is impossible for the bucket to float and close the valve with this vent open. As soon as the air has been elimi nated and steam comes to the trap, the heat bends the strip of thermic metal sup porting a flat disc which closes the large vent. Thereafter, the trap functions in the normal manner. This thermic bucket can be supplied in any size Armstrong trap. The table on the following page gives the prices for traps so equipped. Avoid Steam Trap Troubles--The customary troubles with steam traps are leaky valves, air-binding and plugging up with dirt or oil. The intermittent action of this trap and the metal used in the valves stop scoring and wire-drawing, the common sources of leakage. Air-binding is impossible because the air passes out of the bucket ahead of the steam through the Armstrong Machine Wor\s Specialties, Heating HOW THE ARMSTRONG STEAM TRAP WORKS vent at the top. When the trap is dis charging, the flow of water under the bottom of- the bucket prevents the ac cumulation of any dirt, or sediment. Simplicity--The Armstrong Steam Trap has only two moving parts--the valve lever assembly and the inverted bucket. Friction is practically eliminated in this mechanism. All wearing parts are made from nickel chrome steel except the discharge valve and seat which are made from a special chrome steel- heat treated after machining to obtain maximum hardness and toughness. Many years of service without maintenance expense is the customary experience of Armstrong trap users. Large Capacity--Discharge orifices used in Armstrong traps are very large in proportion to the size of the pipe con nections. Armstrong trap capacity ratings are not theoretical but show actual test capacities when handling condensate at steam tem perature. The effect of flash steam and pipe friction to and from the trap is thus automatically taken into consideration. Service Organization -- The satis factory operation of all Armstrong traps is assured by 44 district representatives in the United States, Canada and Hawaii. Stocks of these traps are carried in nearly 100 leading cities. We will gladly put you in touch with your nearest representative and see that any traps you need are sup plied promptly. Sizes, Capacities and List Prices of Armstrong Traps ; Trap Size No. 200 and 201 Pipe Connections................... List Price (Regular).............. List Price (Blast Trap)........ Telegraph Code (Regular).. Telegraph Code (Blast Trap)........... Height...................................... Diameter.................................. Weight...................................... Maximum Pressure............... Vi* y* $7.00 $8.50 fAcacia (Acanthus /Acacette 1 Acanette 4" w 3'/ Lb. 125 5 10 15 20 25 Continuous discharge capacity ,, 30 in. lbs. of water per hour at )3 40 pressure indicated. For more complete information, see the i 5600 Capacity Chart in the Arm- 4 70 strong Steam Trap Book. 3 80 J 90 100 125 150 300 250 450 560 640 690 460 500 550 600 635 660 690 640 650 660 No. 211 No. 212 No. 213 No. 214 '/,* $9.25 $10.75 W <*'/*' Vz VS $15.00 $20.75 $17.00 $22.75 1" $29.00 $31.50 Aspen Birch Walnut Hemlock Aspette 6>/,' w 51/2 Lb.200 Birette 8* 5' I0'/2 Lb. 200 Waiette IO'/4" w 19 Lb. 250 Hemlette Wz' w 32 Lb. 250 840 1000 1080 890 940 970 780 840 900 940 800. 840 880 960 820 900 ,, 1560 1900 2060 1800 1940 2050 1700 1840 1950 2030 1650 1750 1840 2040 1530 1680 3000 3500 3900 3100 3390 3600 3450 3750 4050 3700 3920 3220 3400 3880 3500 3200 3500 4600 5600 6300 5900 6300 6600 5700 6200 6600 6100 6400 6100 6300 6700 5900 5400. 5700 No. 215 No. 216 I" or V/S \W or 2" $38.00 $55.00 $40.50 $60.00 Larch Tamarack Larette 14* Wi" 47 Lb. 250 Tamrette 163/,' IW 76 Lb. - 250 7600 9100 10,000 8500 9200 9800 8400 8900 - 9300 9200 9700 10,100 10,400 10,900 9500 9500 10,200 14,30017,200 19,000 18,200 20,000 17,600 20,000 18,200 19,600 18,500 19.800 18,000 18,500 20.400 18,600 17,400 19,000 Specialties, Heating The Beaton & Cadwell Mfg. Company Main Office and Factory: New Britain, Conn. New York Office: 234 Water Street CADWELL No. 45 SYSTEM FOR HOT WATER HEATING SYSTEMS . A complete unit nothing else to buy. ' A departure from the conventional type of equipment as used with tank in basement systems. To keep the expansion pressure in the system within practical working limits even under sudden firing methods, as in oil burners. Providing means for elastic pressure distribu tion within the system. Keeping the system filled to any desired pres sure, and above all--to positively protect the boiler. All of this is achieved in a novel manner. The combined pressure governing and relief feature--which is new: . 1. Has no springs. 2. Is governed entirely by physical laws. 3. It cannot increase the setting at any time. .4. It tests itself automatically as long as there is any water in system. 5. It is'responsive to the slightest dif ference of pressure within the system. 6. Absolutely guaranteed to protect the boiler. The filling arrangement is automatic and can be varied in pressure from 5 to - 20 lb by adjusting screw. A large strainer prevents foreign matter from entering system. The strainer, valve disc and seat can be cleaned at any time without losing water out of system. Valve and tank supplied in Maroon . color. Layout shows simplicity of installation. Cadwell No. S Control Unit Cadwell No. 5 ContTol. Unit For Hot Water Heating System. A Feed valve-- Relief valve--Ball check--Screen and Back pressure valve all in one unit. Closed by internal pressure not by heavy spring, eliminating sticking valve seats. Feeds to 15 lb, relieves at 30 lb. Feed valve and Relief valve can be tested by pushing down on cap. Feed valve and screen can be in spected and cleaned without drawing water out of system. Cadwell No. 15 Relief Valve Built on same princi ple as No. 5 for relief of pressure only in Hot Water Heating sys tems. Cadwell No. 15 Relief Valve Perfection Floor and Ceiling Plates Floor and ceil ing plates to answer even' re quirement. Genu ine Perfection No. 10, as illustrated --sheet steel or brass--sizes 34 in. to 6 in. inclusive. Other types No. 10 available in cast . iron or brass in pipe sizes % in. to 12 in. inclusive. Furnished in plain, nickel plated, chrom ium plated or desired finishes. 1010 The Beaton & Cadwell Mfg. Company Specialties, Heating CADWELL THERMOSTATIC AIR VALVES FOR ONE PIPE STEAM AND VACUUM SYSTEMS Bottom Outlet H and %-in. and H * H-tn. sizes No. 10 Non-Adjustable Thermostatic Valves Bottom Outlet \4-in. and $ x /l $-in. sizes No. 0 Non-Adjustable Thermostatic Vacuum Valves Bottom Outlet %-in. and % x }$-in. sizes No. 50 Diaphragm Operated Thermostatic Vacuum Valves to "Equalize" One Pipe Steam Systems No. 10--Regular, for radiators, non-vacuum, our best all metal syphon air valve. No. 10 S. S.--Same as No. 10 except straight shank for venting return lines etc., made in the following sizes: % in. I. P. S. K in. I. P. S. % in. Female Thread x % in. Male Thread. - No. 20--Check operated vacuum air valve for radiators. No. 20 S. S.--Same as No. 20 except straight shank for venting return lines, etc., made in in. I. P. S. and in. Female Thread x % in. Male Thread. No. 50--Diaphragm operated vacuum air valve, closes efficiently against the escape of steam or vacuum. Large closing surface of diaphragm, through nickel silver pin forces check off seat with every closing of main valve by steam or vacuum, positively preventing the sticking of valve. Use this valve to "Equalize the System." Valve is constructed so that port vent can be increased in size to allow distant or sluggish radiators to heat, and equalized " radiation results. .' No. 50 S. S.--Same as No. 50 except straight shank for venting return lines, etc., made in J4 in. I. P. S. and % in. Female Thread x % in. Male Thread. RANGE BOILER OR TANK RELIEF VALVES Cadwell No. 25 Temperature, Pressure and Vacuum Relief Valve for use on Range Boilers or Hot Water Storage Tanks The opening and closing of valve is governed en tirely by internal pressure, not by a heavy spring forcing valve on to seat. Valve is self-closing, opens to allow the escape of temperature at about 210 deg, pressure 150 lb. Pressure setting can be sup plied according to requirements of different cities. Vacuum release prevents collapse of boiler in case of break in supply line. Only one seat. Valve may be tested by pressing down on top of valve. Cadwell No. 5 Relief Valve . Cadwell No. 35 Pressure and Vacuum . Relief Valve This valve is similar to No. 25 except it does not operate by temperature. Standard valve set to relieve pressure at 150 lb and slightest vacuum. . ion , Cadwell No. 85 Pressure and Vac uum Relief Valve Specialties, Heating C. A. Dunham Company Administrative and General Offices 450 E. Ohio Street, Chicago, 111. Factories: Marshalltown, Iowa; Michigan City, Ind.; Toronto, Canada Akron, Ohio Albant, N. Y. Allentown, Pa. Atlanta, Ga. Baltimore, Md. Bangor, Me. Birmingham, Ala. Boston, Mass. Buffalo, N. Y. 1 Chamfaign, III. Chattanooga, Tenn. Chicago, III. Cincinnati, Ohio Clarksburg, W. Va. Cleveland, Ohio - Dallas, Texas SALES OFFICES Davenport, Iowa Denver, Colo. Deb Moines. Iowa Detroit, Mich. Duluth, Minn. El Paso, Texas Grand Rapids, Mich. Greenville, S. C. Harrisburg, Pa. Houston, Texas .. Huntington, W. Va. Indianapolis, Ind. Johnstown, Pa. Joliet, III. Kalihpell, Mont. Kansas Citt, Mo. Kingston, Pa. . Little Rock, Ark. Los Angeles, Calif. I^iifflv 11.t.B, hi. Memphis, Tenn. Milwaukee, Wis. Minneapolis, Minn. Missoula, Mont. Newark, N. J. New Haven, Conn. New Orleans, La. New York,' N. Y. Oklahoma Citt, Okla. Omaha, Nebb. Philadelphia, Pa. Pittsburgh, Pa. Plattsburgh, N. Y. Portland, Ore. Poughkeepsie, N. Y. Providence, BL L Richmond, Va. Rochester, N. Y. St. Louis, Mo. Salt Lake Citt, Utah San Antonio, Texas San Francisco, Calif Seattle, Wash. Springfield, Mass. STEACUKE, N. Y. Tampa, Fla. Toledo, Ohio Trenton, N. J. Washington, D. C. Wichita, Kan. C. A, Dunham Co., Ltd.,' 1523 Davenport Road, . Toronto, Ont., Canada C. A. Dunham Co., Ltd., (of the United Kingdom) Morden Road, London, S.W. 19, England Over eighty sales offices in the United States, Canada and the United Kingdom bring Dunham Heating Service as close to you as your telephone. These representatives are available for engineering counsel in correct selection of Dunham Systems and Appliances for any type of building. The accumulated experience of the entire Dunham organiza tion is put at the disposal of the Heating and Ventilating Engineer. This cooperation is . available for Modernization Work, as well as for new construction in industrial, com mercial and other projects. DUNHAM DIFFERENTIAL VACUUM HEATING The advantages of the Sub-Atmospheric principle which governs steam distribution in Dunham Differential Vacuum Heating Systems are utilized in'three distinctive applica tions. Modifications of past standards of heating, such as the Vacuum Return Line systems and the Vapor systems, are definitely improved by relating certain Dunham equipment. The use of this equipment is explained in the Dunham Hand Book (No. 514). 1. The Dunham Differential Vacuum Heating System for High Duty--This is a two-pipe system giving excellent room temperature control and winter air con ditioning. The pressure, the temperature and the volume of steam in circulation are varied under a control which is a normal function of system operation. The wide range over which the vacuum and quality of steam in the radiators is regulated (from atmosphere to 25 in.) establishes correct rates of heat emission with radiators either complete or partially filled as required. A continuous valuation of heat requirements under positive temperature control may be secured through nine thermostats in a building, or zone of a building. The Hugh Duty Differential System is a functioning part of the Dunham Average Temperature Control System. ' Ventilation and Air Conditioning Application--Differential heating also gives effective service on blast heaters on ventilation and air conditioning systems. Differential control of steam temperatures and volume reduces the percentage of by-pass air and makes possible more accurate control of outlet air temperatures and humidities. 2, The Dunham Differential Vacuum Heating System for Low Duty--The design of this system embraces equipment of the same general type as used in the High Duty System. Its fuel economy closely approaches that system but it does not claim the same preciseness of temperature control as characterizes the High Duty System. However, the principle of control is the same as in that system ; the radiator* tempera . tures are varied and radiators may be either completely or partially filled according to the heat loss requirements. The vacuum, however, is limited to fifteen inches. The Low Duty System can be very effectively related to existing buildings in changing C. A. Dunham Company Specialties, Heating over ordinary vacuum return line systems to differential operation. One or more ther mostats coupled with Dunham Heat Balancer may be used with a Low Duty System. 3. The Dunham One-Pipe Vacuum Heating System with Sub-Atmospheric Steam--In this system the range of steam temperatures and pressures is ample to give great flexibility of operation in the lower range of vacuums. This system is designed primarily to enable owners of existing one-pipe systems to obtain the benefits of the Dunham Differential Vacuum principle of operation by rearrangingthe system to operate on that principle. The change-over can be made without extensive cutting of floors or walls. Systems having air line will usually require no such cutting. Dunham Line of Pumps for Differential Vacuum Heating Systems and for Vacuum Return Line Heating Service The operation of these pumps is characterized by a quietness which is outstanding. Its use contributes to this essential of satisfactory heating--quietness --while supplying a vacuum producing means of great effec tiveness and time proved in its ability to perform consistently over long periods of time with minimum of attention and main tenance. The unit combines added re finements of construction in cluding ball bearing centrifugal pump of improved design, dis charge valves operated by a powerful mechanism and other refinements. The pumps are built in eleven sizes, ranging from capacity of 2,500 to 150,000 sq ft of radiation inclusive. These pumps fulfill the adopt ed standard for the American Society of Heating and Ventilating Engineers and likewise the requirements of the Vacuum Return Line Heating Pump Manufacturer's Section of the Hydraulic Institute. Pumps to meet special requirements will be supplied. THE DUNHAM HAND BOOK The Dunham Hand Book--No. 514. Com prehensive manual for architects and engineers dealing with the principles, designing, equip ment and installation of heating systems which circulate steam under variable sub-atmospheric pressures, variable low pressures and variable volumes to give dynamically balanced tempera ture regulation in buildings. Contents' include treatment of steam heating history, development of controlled heating, principles applied in the differential heating system, piping design and tables, equipment application with installation diagrams, ventilation, unit ventilators and air conditioning applications, unit heaters, con cealed radiators, auxiliary steam service ap pliances, miscellaneous engineering and heating data and tables. 4C4 pp. Specialties, Heating Thames cjones 129 Brookside Avenue, Jamaica Plain, Boston, Mass. New York Office: 101 Park Avenue Barnes & Jones Vapor and Vacuum Systems of Steam Heating; Modulation Valves; Packless Quick Opening Supply Valves; Metering Orifice Supply Valves; Thermostatic Radiator Traps; Thermostatic Traps for medium and high pressures; Condensators (Boiler Return Traps); Drip Traps; Heavy Duty Blast Traps; Vent Traps; Strainers; Damper Regulators; Gages; Proportions tor Systems with Zone Control Modulation Valves, Type K With indicating dial, non-rising stem; renewable disc seat. Tail piece . extra heavy to pre vent breakage, extra long to facili tate connection to radiator. Furnished with either lever or wheel handle. Vl In. Cap. Sq Ft Rad... 30 Va In. 60 1* la. 100 1% In. ISO Thermostatic Radiator Traps The interchange able control unit contains the ther mostatic element, carries its own seat of special alloy and is a complete oper ating unit in itself. Calibrated under actual working pressure at the factory and locked in adjustment. Unit easily and quickly replaced without special tools; lift out the old unit and insert a new one. Made in low, medium, and high pressure types. Symbol 12| 120 124 134 13 14 Packless Quick Inlet Tapping....................... $ faOutlet Tapping.................... Vi 200 i 1200Capacity. Sq FtC. l.Rad..| 200 V* Va" 400 400 r r Opening Valves Float and Thermostatic Traps Type F For use on Unit Heaters, Non-rising stem renewable disc seat. Furnished with wheel handle only. Drip Type also drips from supply mains and risers and on returns from water heaters and indirect stacks. Float-controlled valve governs discharge of water; thermostatically-controlled valve Condensators allows passage of all air but prevents passage of steam. Made with % in., 1 in. and in. tappings. Capacities 200 lb to For returning water of condensation to boiler from open return line systems in dependently of boiler pressure, without change in operating conditions, air binding, or admitting steam to return side. Simple in construction, but positive in operation. All working parts are of best bronze metal. 1200 lb of water per hour at 2 lb pressure differential. Combination float and ther mostatic traps with an air and water capacity large enough to take care of the condensation Hmvp Dap Type from the largest vento stacks, dry kiln coils, hot water heaters and other units condensing large quantities of steam at low pressures. Made in sizes from 1 in. to 2 in. Ca pacities to 14,000 lb of water per hour at 2 lb pressure differential. 1014 Specialties, Heating GUNNELL COMPANY. Heating, Industrial and Power Plant Piping, Fittings, Hangers, . Valves, Pipe Bending, Welding, Piping Supplies, Etc. Executive Offices: Providence, R. I. National Distributors of Thermoflex Traps and Heating Specialties For data on other Grincell Products, see pages 919-921 . Thermoflex Specialties Thermoflex High Pressure Traps The heart of all Thermoflex Traps is the Hydron Bellows. The Hydron Bellows is formed under hydraulic pressure. This powerful internal pressure locates any weakness of any nature in the tubing. Such hydraulic pres sure is many times more severe than any pressure the Trap will ever be called upon to control. Every Thermoflex Trap, there fore, is practically indestructible. Thermoflex Traps have an exceptionally large orifice. This large orifice combined with high lift, insures fast action and freedom from clogging. We supply Thermoflex Traps guaran teed for steam pressures up to 25 lb. and to 125 lb. Complete information and details of typical installations will, be gladly sent on your request. Ask for Catalogue on Thermoflex Heating Specialties. Valves, Traps, Gauges, Etc. The Thermoflex line includes: Radiator Traps, Offset Traps, Blast Traps, Drip Traps, High Pressure Traps, Vent Traps, High-grade Packless Inlet Valves, and the Thermoflex Alternator, Thermoflex Com pound Gauge, Thermoflex Damper Regu lator. NO. 12 Thermoflex Radiator Trap The No. 100A Thermoflex Trap is guar anteed . for steam pressures from 25-125 lb. Must not be used where the steam temperature exceeds 400 F. For use with all types of process work, Laundry Machinery, Kitchen Equipment, Hospital Sterilizers, Vulcanizers, Dry Kilns, Unit Heaters, Street Steam Service; etc., in fact any place that a trap is desired for service at the above pressures. Small, compact and inexpensive in com parison to the usual float or bucket trap. Extra heavy body. Renewable nickel steel seat and disc. Bellows made from special bronze tubing and encased in brass sleeve to prevent distortion due to pressure. Regularly furnished without unions, plain nickel finish. Can be furnished with unions, polished nickel or chromium plated at extra cost. No. 4 Thermoflex Drip Traps The full eight-fold Thermoflex-Hydron Bellows is the best bellows ever made. Because of the Hydron-forming. process every bellows is absolutely perfect. Body is heavy bronze construction throughout. Fully nickel-plated with highly polished' trimmings. The No. 12 is made in angle and in' comer patterns, with in. inlet and )/2 in. outlet tappings. The inlet neck is double thick to allow for expansion strains. Guaranteed for steam pressures up to 25 lb. Used for dripping mains, risers, coils and unit heaters. Cast-iron body, bronze cap and inserted renewable bronze seat, angle pattern only, without unions. Can be used for any general purpose where a finished, nickel-plated trap is not necesr sary, and at a lower cost. Guaranteed for steam pressures up to 25 lb. ; ' See also Pages 919-921 1015 Specialties, Heating Hoffman Specialty Co., Inc. General Sales Department 500 Fifth Avenue, New York, N. Y. Main Office and Factory: Waterbury, Conn. Sales Representatives in Principal Cities Manufacturers of Adjustable Port Radiator Venting Valves, Quick Vents and Air Eliminators for One and Two Pipe Steam and Vacuum Systems; Hoffman. Supply Valves, Traps and Basement Specialties for Controlled Heat Systems; Hoffman-Economy Vacuum and Condensation Pumps and the HoffmanTallmadge System of "Zoned Controlled Heat." . Hoffman offers a complete line of Radiator Air and Vacuum Valves and Quick Vents for every venting purpose on One or Two Pipe Steam Systems. The entire line of radiator venting valves is equipped with the Six-Speed Adjustable Orifice Venting Port illustrated at left), making it possible to balance the steam distribution in One-Pipe Steam Systems accurately, by increasing or decreasing the rate of venting of each radiator, which controls the flow of steam into that radiator. SIPHON AIR VALVES The.Nos. 1, 70 and 71 are used for venting radiators on One or Two Pipe Steam Systems, and the Nos. 4, 5 and 75 are used in conjunction with these valves for venting steam mains, risers and other quick venting services. OPERATION OF THE No. 1 VALVE One of the vent ports is always open, regardless of the port adjustment. The larger ports allow a more rapid rate of venting than standard and the smaller ones a slower rate of venting and thereby control rate of steam flow into the radiators. When steam reaches the float, vaporization of the heat sensitive fluid within the float expands, with "snap" action, the flexible diaphragm forming the float base and raises the valve pin to its seat, thus preventing the passing of steam. Whenever air reaches the valve, its lower temperature reduces the fluid pressure within the float. The diaphragm contracts and the port is opened for the escape of the air. Should water surge into the valve, the float raises by its buoy ancy thereby forcing the pin to its seat and preventing the escape of water through the vent port. As soon as water drops below the valve connection, air must enter the float chamber before the water can run out. Air enters through the valve connection and passes up through the air channels in the double shell construction to the top of the valve. As the air enters it displaces an equal volume of water through the siphon connection and allows the float to drop and open the vent port, allowing the air to escape. VACUUM VALVES The Nos. 2, 77 and 78 Vacuum Air Valves operate on a similar principle as described above, but in addition feature the Hoffman Double Air Lock con sisting of the vacuum check and vacuum diaphragm. These valves are used on One Pipe Vacuum Systems; and for venting the ends of steam mains or heating risers, where it is also desired to prevent the return of air into the system, the Nos. 6, 16 or 76 Float Vacuum vents are used. 1016 Hoffman Specialty Co., Inc. Specialties, Healing HOFFMAN CONTROLLED HEAT A Hoffman Controlled Heat System consists of the No. 7 Adjustable Orifice Modulating Valve on the supply end of the radiator, the No. 8-A Thermostatic Trap on the return end and either a Hoffman Differential Loop (for coal-fired installations operating at pressures up to 8 ounces), or a Boiler Return Trap where higher pressures are encountered, for returning the condensate to the boiler. No. 7 Modulating Valve SUPPLY VALVES Besides the No. 7 Adjustable Orifice Modulating Valve the Nos. 37 and 47 series represent a complete line of Packless Supply Valves that meet the exacting require ments of architects and engineers. THERMOSTATIC TRAPS The line of Bellows Type Thermostatic Traps, with hydraulically formed and tested bellows, consists of the Nos. 17-A, 18-A, 8-A and 9-A, and are principally used for low pressure steam or vapor systems. These traps have nominal capacities from 200 sq. ft. up to 600 sq. ft. of radiation. The Nos. 8-A and 9-A have renewable elements, which combine the thermostat, valve pin and renewable seat into a single unit. The No. 10-A Hoffman Trap, which is equipped with waterhammer proof bellows, X in. connection, has a nominal capacity of 2800 sq. ft. The Nos. 8 and 9 Traps have a thermostatic element consisting of three chambers each having a top and bottom diaphragm. These chambers are all joined together and the complete thermostatic member is housed in a cage and is not attached to the valve body or cap. This allows the thermostatic element and valve pin to be easily removed and replaced without adjustment. These traps range in sizes from % in. to 1 in., are medium pressure traps, and are recommended where pressures up to 50 lbs. are encountered. . The Nos. 20-A and 21-A High Pressure Traps are equipped with waterhammer proof bellows and integral strainer, for use on pressures up to 100 lbs. Available in % in. to 1 in. connection. . DRIP AND HEAVY DUTY TRAPS Where large amounts of condensation are encountered, it is recommended to use one of the float and.thermostatic traps, which are available with or without the thermostatic element. -These traps are available in large capacities and are mainly used for venting and dripping risers, steam mains, unit heaters, blast coils, etc. VACUUM AND CONDENSATION PUMPS The Hoffman-Economy line of Vacuum and Condensation Pumps offers a dependable method of economically returning the condensation from larger heating systems to the boiler. These pumps aremade in single and duplex units, for varying capacities and pressures. ZONED CONTROLLED HEAT The Hoffman-Tallmadge System of Zoned Controlled Heat is a development for accurately controlling the temperatures of large buildings or portions thereof, with Precision Orifices and'Zone Control Valves either manually, thermostatically or remotely controlled. HOFFMAN SALES AND SERVICE Hoffman Products are sold and stocked by leading wholesalers of heating and plumbing supplies everywhere. Hoffman representatives' are available to assist in selection of suitable equipment for various services. Specialties, Heating ILLINOIS ENGINEERING COMPANY General Offices and Factory: Chicago Branches and Representatives in Principal Cities Illinois Thermo Radiator Traps Illinois Thermo Ra diator Traps for vacuum, vapor and low pressure heating sys tems. Has SeriesG cone type valve. Flushes thoroughly and seats perfectly at all times. Valve and seat are of Nitralloy. The duplex diaphragm is of special phos phor bronze. Scientific design and rugged construction assure flexibility and long life. These diaphragms have withstood over three million strokes on a breakdown test. Will withstand 75 lb. steam pressure without damage although only low pres sure service are required of them. Made in three sizes from J^-in. to 2-in., in a variety of patterns. Furnished in either plain or nickel plated finish. Illinois Thermo Radiator Trap The Original Vertical Seat Trap. Self clean ing, non-adjustable. Positive and sensitive in operation. Thousands in use for over fifteen years without diaphragm replacements. Fur nished in all sizes and patterns. Illinois Modulating Supply Valve Quick-opening, packless. Steam tight on 50 lb. pressure.. Large diameter of thread spool andmachine cut threads make valve operation easy. Furnished in a complete line of sizes and patterns. Illinois Combination F & T Traps Unsurpassed for draining ventilating units, unit heaters, and for dripping mains and risers-- wherever it is desira ble quickly to vent air from the main as well as handle the water of condensation in quantity, whether hot or cold. Illinois Combination Trap This is the heavy duty type similar in operation to the 6G, 7G, and 8G traps. Series 36 traps are available in a complete range of sizes. They are equipped with sep arate thermostatic by pass and are furnished where specifications re quire this type, or where capacities are beyond the range of the 6G, 7G or 8G. Illinois Return Trap Automatic ally returns the condensa tion to theboiler, regard less of pressure on the boiler up to 8 lb., at the same time discharging the air. Insures positive and complete circulation, and prevents cracked boiler sections. Trap is self-contained, with no external working parts to be misadjusted, tampered with or injured. No stuffing boxes or packed joints, which insures continuous tightness against air or water leakage. Write for Bulletins 1018 Illinois Engineering Company Specialties, Healing ILLINOIS ENGINEERING COMPANY General Offices and Factory: Chicago Branches and Representatives in Principal Cities Illinois Thermal-Zone Control Prevents over heating and fuel waste in large buildings 1 or groups of buildings heated from one central power plant. Buildings may be zoned as to occupancy, time, location, exposure and so on. In many installations this valve has paid for itself in one heating season. Illinois Reducing Valve In general use on vacuum or low pres sure heating systems. Will reduce to 4 oz. pressure from an in itial pressure of 150 lb. The large diaphragm insures sensitive opera tion. Made in both straightway and ex panded outlet bodies in sizes from % in. to 12 in. Master Type Pressure Regulator For exacting re quirements, such as tire and rubber vul canizing, chemical process pressure control, and wher ever high pressure steam must be ac curately reduced in varying amount to any steady lower pressure not less than 10 lb. It will reduce initial pressure up to 300 lb. down to any lower pressure not less than 10 lb., and does not build up pressure on a closed or dead end line. Made of bronze with monel metal valves and seats. . Illinois Steam Trap Valve and s t e m are separate from the bucket and operatedonly by the bucket at the ex treme top and bottom of travel-- result--valve is always Series SO either full open or tight closed. No wire drawing or cutting of valve and seat which are of Monel metal. Eclipse Spring Controlled Regulating Valve Fig. Ill Furnished in either single seated or double seated type as the service conditions re quire, for the control of steam, air or gas. Con trolling spring is completely enclosed, protecting it from dirt and rust. Valves are furnished with the . proper size diaphragm and the proper length spring to give satisfactory service'- under all operating conditions. Steam and Oil Separators Eclipse steam sepa rators are made in both horizontal and vertical type, and also the special receiver sepa rators for standard or extra heavy pressures. Eclipse oil separators are furnished in the horizontal type and have a removable baffle Vertical standard plate to facilitate clean- Separatms ing of baffle andkeep- ing the separator's effi ciency at the highest point. Write for Bulletins Specialties, Heating William S. Haines & Company . 12th and Buttonwood Sts., Philadelphia, Pa. Manufacturers of Equipment for Vapor and Vacuum Heating Systems PRODUCTS--Haines Vento Radiator Traps, Medium Pressure and Blast Type Traps, Com bined Float and Thermostatic Blast Traps, Air Eliminators, Heavy Duty Float Traps, High Pressure Traps, Boiler Return Traps and Packless Inlet Valves and Modulating Supply Valves. All Haines Traps, whether designed for pressures below atmosphere or pressures in excess of 100 lb. per square inch, employ as their operating member a specially constructed Bourdon Tube--the principle that actuates the steam gage. Haines Thermostatic Trap The tube is of tempered steel. It is charged with a volatile fluid and hermetically sealed: It is the expansion and contraction of the fluid, under varying temperatures, that furnishes the operating power. The tube is mounted vertically on a horizontal valve motion. The end opposite the valve is anchored so that the travel of the tube either opens or closes the valve piece. The thermostatic member is outboard the valve seat and closes the valve against the flow of steam. This arrangement prevents fouling of the trap due to scale or other foreign matter and permits a thorough draining of the unit to which it is attached. THERMOSTATIC TRAPS Haines Thermostatic Traps are constructed to endure, as well as to operate efficiently, in sizes ranging from ]/2 to 13^2 in. They, are thoroughly inspected and proved in our test laboratory under operating conditions to insure their serviceability. ' Haines Modulating Valve A MODULATING VALVES '' Haines Modulating Valves are permanently packed, furnished with a genuine Jenkins Bros, valve disc. . Its modulating features permit varying the amount of steam admitted to the radiator. They seat tightly and open full area on less than a complete turn. Furnished in Lever, Round Handles or Locki Shield, type. The body is made of heavy brass, nickel plated with polished trimmings. ' Made in sizes from to 2 in. in angle, straightway or corner patterns. 1020 Specialties, Heating Kieley & Mueller, Inc. Established 1879 Engineering Specialties for Pressure and Flow Control 34 West 13th Street, New York, N. Y. Factory: NEWARK. N. J. Agents in All Principal Cities PRODUCTS--Valves: Altitude, Stop and Check, Pressure Regulating, Float, Pilot Reducing, Back Pressure, Tank Control. Liquid Level Controllers, Water Feeders, Pump Governors, Steam Traps, Strainers. ' Also Damper Regulators, Hot Water Temperature Controllers, Oil Separators, Steam Separators, Return Traps, Water Columns, etc. Catalogs sent upon request Pressure Regulating Valve Spring and lever weighted valves for all services and for initial pressures up to 250 lb. and reduced pressures from 0 to threequarters of the initial pressure. Single or double seated in sizes % to 16 in. Suitable for steam, water, air, oil and gas. Con trolled by a small feeler pipe connected from diaphragm to low pressure side. Steam Traps Large capacity, small sized inverted ' bucket traps; quick acting, self-cleaning and non-air bind ing. Sizes % to 2 in. Pressures up to 250 lb. Body and cover, semi - steel. Valve and seat, stainless steel. Re movable cap allows inside inspection or replacement of valve parts without disturbing pipe connections. (All parts are interchangeable). Back Pressure and Atmospheric Relief Valve For use where plant is operated either con densing or non-condensing. Outside air dash pot insures noiseless operation. Maintains exhaust line back pressure from 0 lb. to 25 lb. Made horizontal or vertical lever and weight or spring operated. For the accurate control of liquids in tanks or other vessels; suitable for use in in-' dustrial plants, gasoline plants, refineries, etc. Direct connected or remote control; ball bearing spindle and easy-to-pack stuffing box; rotary or sliding valve. Write for special bulletin C-3. Specialties, Heating J. E. Lonergan Go. 207 Florist Street, Philadelphia, Pa. Pop Safety Valves; Relief Valves; Steam Gauges; Hydraulic Gauges; Air Gauges; Water Gauges; Pressure and Temperature Gauges; Test Gauges; Gauge Boards; Oil Gauges; Clocks; Counters; Gauge Cocks; Steam Gauge Syphons; Lubricating Specialties. Modd "GV" Model GV--Vacuum Gauge. Gauges graduated to 30 in. vacuum. Ten sizes, to 10 in. dial. Model BLGR--Gauge for indicating height of water in feet. Graduation 70 ft. Three sizes, 3J4, 4J4 and 5 in. dial. Model "BLGR" Modd "GLP" Low pressure, Iron Body, Brass Mounted. - Set to blow off at 10, 15,20, 25 or 30 lb. - Five sizes-2}^ to 4J4 in. Modd " U" Relief Valve. Snifter, Water or Cylinder-- Bronze. Recommend ed for steam en gines, pumps, pipe lines, etc. Ten sizes, Vi to 4 in. Oil Relief Valve. Sizes % to 2 in. For use on oil burning systems. Has large reliev ing capacity. \ Model "VAK" Special valve for vacuum breaking. Six sizes, H to 2 in. Positive in its ac tion. \ Water Relief Valve for tank service. * . Sizes %, and % in. Pop Safety Valve A.S.M.E. "House Heating Boiler." Standard pressures, .5, 10` and 15 lb. ' Model "WRV" CATALOGUE Write for our new 100-page cata logue, describing and illustrating the complete "Lortergan Line" or ask us about specialties in which you are interested. 1022 Model "HUD" Specialties, Heating Mueller Steam Specialty Co., Inc. 349-351 West 26th Street, New York City Steam, Water, Air, Oil and Gas Specialties for Heating and Power Plants No. 11--For Vacuum, Vapor and Low Pressure Heating Systems. Initial Pressures, up to 200 lb.; Reduced Pressures, 0 to 10 lb. ' No. 17 and 21--For automatic control of reduced pressures on dead-end service, requiring a tight closing valve, such as tank heaters, kitchen utensils, sterilizing ap paratus, laundry equipment, kettles, cookers, driers, etc. Initial Pressures up to 200 lb. Reduced Pressures 0 to 150 lb. ' _ Constructed with full globe bodies. Center guide eliminates the wings on discs, and increases efficiency, assures minimum noise and prolongs the life of the seats and discs. Lever and weight operates on a steel roller bolt, assuring a most sensitive valve. Spring type furnished with special long springs for sensitive operation and wide ranges of reduced pressures. ' Automatic Water Feeders With a powerful leverage to control the water line in steam boilers, etc. They supply make up water to compensate for evaporation, leaks, steam utilized in process work and condensation wasted. "Where condensation held up in the system eventually returns in large No. 517--Duplex quantities, our Duplex type protects Up to 22J00 Sq. Pt. die boiler against flooding. All working parts of non-corrosive metal, are accessible without breaking pipe connections. Provided with an integral strainer. For steam pressures up to 100 lb., water pressures up to 120 lb. ` Steam Traps Simple, Sturdy and Compact Ball Float and Inverted Bucket Steam Traps for draining water of condensation from steam apparatus and steam mains. Powerful leverage enables them to take care of large quantities of condensation. Ball Float Steam Traps equipped with integral strain er, water gages, air cocks, blow off and integral by-pass valve, when desired. All working parts are ac cessible without disturbing Bail Float No. HO--Up to SO lb. No. SSI--Up to 150 lb. Site* % to 9 in. any pipes. Valves are sealed with sev eral inches of water, making theescape ofsteamimpossible. Inverted Bucket No. til--For PreMure* Up to 250 W. Size* Mtot in. Catalogue and Bulletins covering our Complete Line gladly furnished on application. Specialties, Heating Sarco Company, Inc. 183 Madison Ave., New York, N. Y. Branches in Principal Cities SARCO CANADA LIMITED, Federal Bldg., Toronto, Ont. PRODUCTS--A complete line of Specialties for Vapor, Vacuum and Gravity Steam Heating Systems, combined with a competent Engineering Service to architects and heating engineers to assist them in providing modern heating. SARCO ^ RADIATOR TRAPS These efficient traps are equipped with bellows made from our own heavy wall, seamless, corrugated bronze Type B tubing. They are exceptionally rug TypeH ged, have long life and high capacity. Available in angle, straightway and corner patterns. heavy brass, nickel plated, with polished trimmings. _ The body is SARCO RADIATOR VALVES For high vacuum heating sys tems, Sarco offers Sarco Bellows- Packless Valve. It is of the truly packless, modulating type. Leakage at the stem is impos sible. The stem is sealed to the Sarco Bellorae-Packleee Valve cap by Sarco seamless, cor rugated bronze tubing. . The Sarco-Marsh valve is of Sarco-Marsh Packless Valve the commercial packless type in which'the stem is sealed by a metal-to-metal cone seat, re-enforced by moulded packing held compressed by a spring. Valve bodies of both types are cast brass, heavily nickel plated with polished trim mings. ... . Can be furnished with round or lever handles, or lock shield, in angle, straightway or comer patterns. . SARCO FLOAT-- THERMOSTATIC TRAPS ' Used for dripping the ends of mains and risers. Also for stack or blast heaters, large unit heaters and hot water generators. Have automatic thermostatic air vents built in. SSnl Available in seven sizes with connections % to 2 in. for " pressures 0 to 200 lb. Sarco "FT" Trap 1024 Sarco Company, Inc. Specialties, Heating SARCO AIR ELIMINATORS For venting air from vapor systems at one central point in the basement. Available in two sizes: No. 6 for. systems up to 2,000 sq. ft. and No. 12 for 15,000 sq. ft. Both 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. SARCO ALTERNATING RECEIVER Air Eliminator No. it A complete line of boiler return traps for vapor systems. Return water of condensation to boiler automatically, thereby assuring posi tive return of water under all pres sure conditions. Made in six sizes for from 1,500 to 25,000 sq. ft. of radiation. Alternating Receiver SARCO MEDIUM PRESSURE TRAPS Type S-75 Steam Trap These thermostatic steam traps are Sesigned specially for kitchen fixtures and hospital equipment. Available in sizes % to 1 in. in two types; S-65 for pressure 15 to 65 lbs. and S-75, 0 to 100 lb. SAKUU 1EMFERATURE REGULATOR A: self-contained automatic valve for controlling temperatures from 0 to 300 F. For hot water heaters, tanks, sterilizers and room control. Available in sizes to 6 in. SARCO DAMPER REGULATOR Specially designed for vapor and vacuum systems. Has 10-in. Type TR-ti Damper Regulator Type D-S . SARCO COMPOUND GAUGE Recommended for vapor and vacuum'systems in place of pres sure gauge. Has 4J4-in. dial, range 0 to 30 lb. pressure, 0 to 30-in. vacuum with extended scale 0 to 5 lb. and 0 to 10-in. for easy reading. Compound Gauge SARCO STRAINERS Pipe line strainers are effective insurance against injury to traps, valves, meters, pumps, etc. Sarco strainers fire made with screens for steam, .water, oil, gas, brine or ammonia. CATALOG For full information on all Heating Specialties write for Catalog HV-45. ' Strainer Specialties, Heating Sterling Engineering Company Representatives Alexandria, La. Atlanta, Ga. Baltimore,* Md. Boston, Mass. Bridgeport, Conn. Buffalo, N. Y. Canton, Ohio Cedar Rapids, Iowa Chicago, III. Cleveland, Ohio Dallas, Texas Detroit, Mich. Dodge City, Kans. El Paso, Texas Grand Rapids,Mich. Kansas City, Mo. 3730 N. Holton Street Milwaukee Wisconsin MANUFACTURERS OF STEAM AND WATER HEATING EQUIPMENT See Telephone Directory for Local Addresses Representatives Knoxville, Tenn. Lafayette, Ind. Los Angeles, Calif. Louisville, Ky. ' Minneapolis, Minn. Newark, N. j. New Orleans, La. New York, N. Y. Philadelphia. Pa. St. Louis, Mo. . San Antonio. Texas Seattle, Wash. Salt Lake City, U. Springfield, Ohio Scranton, Pa. Toledo, Ohio Waukegan, III. PRODUCTS The 1936 models of Sterling products are the result of twenty years' experience in the manufacture of heating control devices. They are designed to provide uninterrupted service for the life of the building. They are guaranteed against mechanical defects and provide the highest degree of attainable efficiency. The products of the Sterling Engineering Company are divided into four groups: Group 1--Products in this group are described in Bulletin No. 234 of the Sterling Engineering Company's loose leaf catalog. They conist of: Diaphragm type thermostatic radiator traps, bellows type thermostatic radiator traps, float and thermostatic traps, blast traps, boiler return traps, bellows packless quick-opening radiator valves, spring packed quick-opening radiator valves, vents and air eliminators, strainers, damper regulators, orifices, air line valves and pressure-vacuum gauges. . Group. 2--Products in this group are described in Bulletin No. 334 of the Sterling Engineering Company's loose .leaf catalog. They consist of: Return line vacuum heating -pumps, condensation pump and receiver units and air line vacuum pumps. Group 3--Products in this group are described in .Bulletin No. 352 of the Sterling Engineering Company's loose leaf catalog. They consist of: Type E No. 100 self-contained thermostatic radiator control valves, Types G No. 101 and G No. 102 remote control valves, Type F No. 103 remote control valves. Type J No. 104 unit heater control valves, No. 110 tank control valves and Nos. 18, 19, 20 and 25 motor operated valves. Group 4--Products in this group are described in Bulletin No. 434 of the Sterling Engineering Company's loose leaf catalog. They consist of: . Sterling Compellers for circulating water in closed circuits, Sterling Instant Water Heaters which heat water instantaneously, using the water from the heating boiler as a heat transfer medium and Sterling No. 21 automatic valves which control the flow of hot water to the heating system. The combination of these products, with the necessary electrical controls and thermostats, constitutes the Sterling Instant System of Water Heating. . The Sterling Engineering Company maintains direct company representatives in the cities listed above. The representatives are engineers schooled in the technique of steam and water heating and are prepared to give technical advice and cooperation to architects, engineers and contractors on the application and use of Sterling equipment. Write the Company at Milwaukee or communicate with our representative for a copy. of our complete loose leaf catalog describing the above mentioned products in detail and giving complete information regarding their use, application and installation. 1026 Specialties, Heating Albant, N. Y. Allantown, Pa. Atlanta, Ga. Baltimore, Md. Birmingham, Ala. Boston, Mass. Brooklyn, N. Y. Canton, Ohio Chicago, Cincinnati, Ohio Clarksburg, W. Va. Cleveland. Ohio The Trane Company La Crosse, Wis. Columbus, Ohio -Dallas. Texas Davenport, Iowa Delanco, N. J. Des Moines, Iowa Detroit, Mich. Findlat, Ohio Flint, Mich. Gainesville, Fla. Harrisburg, Pa. Indianapolis, Ind. Juneau, Alaska Branch Offices: Kalamazoo, Mich. Kansas Citt, Mo. La Crosse, Wis. Little Rock. Ar* Louisville, Kt. Los Angeles, Calif. Memphis, Tenn. Milwaukee, Wis. Missoula, Mont. New Haven, Conn. New Orleans, La. New Yore, N. Y. Oklahoma Citt, Okla. Omaha, Neb. Oshkosh, Wib. Peoria, III. Philadelphia, Pa. Phoenix, Afiiz. Pittsburgh, Pa. Portland, Ore. Portsmouth. Ohio Richmond, Va. Rochester, N. Y. Salt Lake Citt. Utah San Antonio, Texas San Fbancisco, Calif Seattle Wash. Shbbtepobt, La. St. Louis, Mo. St. Paul, Minn. Stracubb, N. Y. Tosowro, Ont., Can. Tulsa, Oela. Washington, D. C. Wilkes-Baree, Pa. TRANE PRODUCTS The many applications of Trane heating, cooling, ventilating, drying, processing and air conditioning equipment make it im possible to discuss them all here. Because of this we are listing for the convenience of the engineer, the architect, and the con tractor a list of available catalogs. Any or all of these catalogs will be sent on request to interested parties. HEATING SPECIALTIES Complete catalog on steam and vacuum heating specialties which includes com plete data on the Trane 14-Corrugation bellows traps and Hermetic Valves. Bulletin on orifice steam heating systems lor residences and buildings requiring up to 800 sq. ft. of radiation. TEMPERATURE CONTROL Bulletin describing the Trane Tempera ture Control Valve with remote control and balanced pressure for controlling room temperatures.-- EXTENDED SURFACE Bulletin containing complete infor mation on the application of Trane extended heat transfer surface to fan systems of heating, drying, and process applications. Complete data. Four Bulletins: - 1. Direct Expansion Cooling. 2. Low Pressure Steam. 3. High Pressure Steam. 4. Water Heating and Cooling. ` COOLING Trane Comfort Coolers. Trane High Velocity Coolers. Trane Product Coolers. CLIMATE CHANGERS A manual and complete bulletin on the residential Air Conditioning Unit for use with steam or hot water boilers. A manual and complete bulletin on the Direct Fired Climate Changer. A bulletin on the Climate Changer for humidification only. HUMIDIFIERS CONVECTION HEATERS Technical data on Trane Convection Heaters. Type and model bulletin--Convection Heater Capacities and Roughing-in Di mensions Trane Convection Heaters. UNIT HEATERS Trane Cascade Humidifier for use with Convection Heater systems. Trane Cli mate Changer Humidifier for hot water and steam heating systems. VENTILATION . The Trane Air-o-Lizer 'a complete heating, ventilating unit for schoolroom ventilation. Trane Floor Line Spread Unit Heater bulletin containing complete Engineering Data with capacities and Roughing-in Dimensions of all sizes of Propeller Fan Type -Units. Trane Torridor bulletin--containing complete engineering data with capacities and roughing-in dimensions of all sizes of Blower Type Units. PUMPS Trane small Centrifugal Pumps for condensate return and circulating work. RAILWAY AIR-CONDITIONING A complete manual on railway air con ditioning equipment arid application of air conditioning units for ice, steam, jet, and mechanical refrigeration systems. 1027 Specialties, Heating WARREN WEBSTER & COMPANY Pioneers of the Vacuum System of Steam Heating fp| Systems of Steam Heating Main Office and Factory: Camden, N. J. Branches in Over 60 Cities Consult Your Local Phone Directory PRODUCTS AND SERVICES Improved Webster Systems of Steam Heating including Vacuum and Type "R" (vapor). Webster Central Control Systems including HYLO and MODERATOR. Modernization of Obsolete and Faulty Heating Systems. Webster System Equipment in cluding Light-Weight Concealed Ra diation (Gravity Convection Heaters), Radiator Supply Valves, Metering Orifices, Thermostatic Traps, Drip Traps, Heavy Duty Traps, Dirt Strain ers, Dirt Pockets, Boiler Return Traps, Vent Traps, Damper Regulators, Boiler Protectors, Lift Fittings, Ex pansion Joints, Separating Tanks, Steam and Oil Separators, Steam Vacuum Pump Governors. Webster Series "78" Traps for use at process pressures (10 to 125 lb. per sq. in.) IMPROVED WEBSTER SYSTEMS The Improved Webster Systems are low pressure, two-pipe systems of steam circu lation with the addition of accurately-sized metering orifices at radiator supply con nections and, when required, intermediate metering orifices at points in branch mains. Metering orifices effect even dis tribution of steam to all parts of the heating system and permit the successful application of a centralized control. Im proved Webster Systems are available for vacuum, open return or "vapor" opera tion. The Type "R" System corresponds to the so-called Vapor type. Fig. 1 illustrates a typical arrangement of Boiler Return Trap, Vent Trap, etc., when low pressure boiler is the source of steam. CENTRAL CONTROL SYSTEMS These are patented systems for varying the amount of steam to all radiators ac cording to outside temperature. They provide continuous heat delivery with effec tive fractional filling of radiators. The Hylo Systems may be provided for manual control, or if desired, may be semi-automatic by incorporation of inside thermostat or thermostat and schedule, clock. The Moderator Systems employ an automatic Outdoor Thermostat sup plemented by a manual Variator. The latter is used for quick heating-up, night load, and unusual weather or oc cupancy conditions. Use of Webster Central Control Systems results in (1) increased comfort because over-heating and underheating are minimized and (2) lower fuel or steam costs. Fig. 1. Conventional arrangement of piping around Webster Basement Equipment for the Webster Type "R" System WEBSTER SYSTEM RADIATION Concealed, non-ferrous type for use exclusively with Improved Webster Sys tems. Is unique in that it combines in a single unit, a light-weight heating element of high efficiency with an orificed radiator supply valve, a radiator trap and supply Fig. t. Webtler Syttem Radiation 1028 Warren Webster & Company Specialties, Heating and return piping connections. Metal enclosures for installation within the wall and exposed metal cabinets are available. Webster System Radiation and enclosures are so designed that the entire heating element can be quickly removed without damage to plaster or paint. Space require ments reduced to a minimum and instal lation greatly simplified. RADIATOR SUPPLY VALVES Type "W" -- Standard supply valve of highest quality. Slotted sleeve gives "modu lation" of steam flow provided proper pressure is main tained on system. Quick-opening, non-rising stem Fig. S. Webster Type " W" Valve type. Uses molded ring packing. Valve disc is renewable. Made in angle, right-corner, left-corner, straightwaysingle union and double union models with either wheel, lever, lockshield, chain wheel or extended stem handles. Sizes: Y, %, 1 and 1]4 in. "Three-Point" Has sleeve orifice fitting into seat opening. Especially desirable for hospi tals, hotels, etc., where quick heat ing-up or higher temperatures are required in different rooms. Is normally Fig. 4. Webster Three-Point Valve an open-shut type but may be easily converted to shut- normal-excess-type. Excess setting gives 140 per cent of normal steam flow. Other wise similar in design to Type "W" Valve. Sizes: % and 1 in. . Sylphon Packless--Positively packless having flexible laminated Sylphon bel lows completely enclosing stem. Quick opening, non-rising stem type. Re newable composi tion disc. Made in angle, right-corner, left-corner and straightway single union models with lever, wheel, lockshield, chain wheel or extended stem handles. Sizes: Yi, %, 1, 1}4, 1Y and 2 in. Type "B"--Quick opening, non-rising stem, packless type. Special gland takes up wear of molded ring packing. Renewable composition disc. Made in angle, right, corner, left-corner and straight-way single union and double union models with wheel, lockshield, chain wheel and extended stem handles. H, 1. 11J6 and 2 in. Sizes: Fig. 7. Metering Orifice Inserted in Union Connection of a Webster Supply Valve Metering Orifices--Accurately sized and made of heavy gage Monel Metal to resist erosion and corrosion, amply thick to be free from vibration and shaped for quiet operation. Available in a number of types to fit both new and installed radiator supply valves of Webster or other make. RETURN TRAPS Sylphon--Original and highly per fected type of low pressure, thermostatic bellows trap. Rugged in construction. Renewable seat. Factory adjusted. Made in angle, right - comer, left - corner and straight way bodies. Sizes: Y, % and 1 in. Normal operating pressures up to 5 lb. per sq. in. Maxi mum occasional pressure 10 lb. per sq. in. Fig. S. Webtter 5IS Sylphon Trap 1029 Warren Webster & Company Specialties, Heating Series "7"-- Perfected dia phragm-type thermostatic .trap. Unusually f strong in con1 struction. Re newable seat. F actory-adjusted, phos phor-bronze diaphragra. Made in angle, right-corner, left-corner and straightway bodies. Sizes: %, and 1 in. Normal operating pres sures up to 5 lb. per sq. in.; maximum occasional pressure. 10 lb. per sq. in. Series "7-M"--Similar in design to Series 7 but built for normal operating pressures up to 15 lb. per sq. in. Maxi mum occasional pressure is 25 lb. per sq. in. Uses Monel Metal diaphragm, valve piece and seat insert. Series "26"--A heavy duty trap for drips of mains, blast radiation, unit heaters and similar applications. A rug ged float-type trap available with and without thermostatic air vent. Made in three sizes: 200, 700 and 1200 lb. water per hour at 2 lb. pressure difference. 700 lb. size has integral dirt strainer; other sizes do not. Maximum working pressure is 15 lb. per sq. in. Series "19" (not illustrated)--A floattype, heavy duty trap for large quantities of water as in hot water generators, fin heater coils and steam mains. Has ther mostatic air vent. Five sizes handling up to 11,700 lb. water per hour at 2 lb. pres sure difference. Maximum working pres sure is 15 lb. per sq. in. Series "16" (not illustrated)--Similar to Series 19 but without thermostatic air vent. For heavy duty applications where concentration of air does not occur. Series "78" -- thermostatic trap built for process steam pressures (10 to 125 lb. per sq. in.). Monel Metal d i a - phragm. Stain less Steel valve piece and seat Fiq. II. Webster Series "78" Trap insert. Angle model only. Sizes: Yi, M and 1 in. Extensively used with laundry, cooking, sterilizing and other process-steam-using equipment. DIRT STRAINERS AND POCKETS Placed in return lines of steam heating systems to prevent dirt, rust and scale from impairing tightness of traps. Fig. It. Size St-C Webster Boiler Protector with Low Water Electrical CuLout Switch. Size 34 has no Cut-out Switch BOILER PROTECTOR Prevents breakage in low pressure heating boilers when water level becomes inadequate. Automatically supplies raw water to boiler when water level.drops to 1 in. above bottom of gauge glass. For maximum boiler pressure of 15 lb. per sq. in. Maximum cold water main pressure should not exceed 150 lb. per sq; in.; minimum must not be less than 25 lb. per sq. in. Made in two sizes, 34 and 030, both with % in. connections. Size 34 can be furnished with electrical cut-out switch. 1030 Specialties, Heating Wright-Austin Co. 317 West Woodbridge St., Detroit, Mich. PRODUCTS--Steam Traps, Strainers, Air Traps, Steam and Oil Separators, Compressed Air Purifiers, Exhaust Heads, Boiler Feeders, Alarm Water Columns, Water Gauges, Trycocks. "Combination" Steam Trap "Emergency" Float Type Steam Trap Three valve trap with large capacity at high pressures. An ex ceptionally reliable trap for use in inac cessible places. Float Type with internal thermo static air bypass and strainer. A modernly designed and very success ful trap for vacu um and pressure heating. Air Relief Trap For relieving air from forced circulation hot water heating systems, water supply lines, closed tanks, receivers, pumps, etc. "Airxpel" Bucket Type Steam Traps Are "double duty " traps, because they automatically discharge both air and condensate. At left is illustrated the "Baby" Airxpel, a new streamline body design, which adds at tractiveness to the installation. Has 'the handiest of all pipe connections for radiation, etc. The Cub sizes are made in H in:, % in., ' 1 in. Especially suitable for in dividual unit drainage on heating and process equip ment. Also, three "Master" sizes in. to 2 in., for general service. May be used two ways-- . as a straight-way or angle;! strainer, in either hori- = | zontal or vertical pipe line, because it has the, choice of two inlets at right angles to oneanother. For cleaning, flush through blow-off connection, or remove screen by unscrewing bottom plug. Boiler Feeder An iron watch man that auto matically main tains uniform water level in low pressure boilers. Separators--Steam and Oil Type "A" Vertical Type "S" Steam - Horizontal Oil "Victor" Low Pressure Steam Trap For heavy vol umes of conden sation at low pressures. We make separators of every type. Send for descriptive Bulletins on any of the items listed on this page. - Stokers Detroit Stoker Company Sales and Engineering Offices General Motors Bldg., Detroit, Mich. District Offices in Principal Cities Main Office and Works at Monroe, Mich. Built in Canada at London, Ont. Since 1898 A Detroit Stoker for Every Service. Each installation, regardless of size is carefully studied from an engineering standpoint to insure best results. Sold ana installed by our own organization. Detroit LoStokcr, showing Motor Driven Blower and Stoker, One Compact Unit at the Front Detroit LoStoker Built in various widths and lengths to fit furnaces of all types of boilers. Com pact, easily installed, responsive and auto matic. Savings, due to increased efficiency, combined with the ability to successfully burn less expensive grades of coal, make Detroit Stokers pay a handsome return on the investment. Write for Bulletin S69. Detroit LoStoker Adjustable Plunger Feed Built in various sizes to fit the furnace Detroit LoStoker Advantages include: Agitator in coal hopper for positive coal feed. Cannot stick or jam with wet coal. Adjustable Plunger Feed for the con trol of the quantity of coal. Heavy Mechanical Drive of simple de sign. Little power is required for operation. Side Cleaning with dumping grates. Ash doors are provided. No hand cleaning. Automatically Controlled. Motor or turbine driven, controlled from steam pres sure, water temperature or thermostat. Detroit UniStoker Large Active Fuel Bed, with Provision for Admitting A ir under the Dumping Grates at each side to burn out the Combustible Prior to Dumping Ashes Detroit LoStokers with Firebox Boilers Detroit UniStoker. Ptunger Feed. Side Cleaning, Motor or Steam Turbine Driven. (Arrows Indicate Flow of Air to all parts of the-Large Active Fuel Bed) 1032 Whiting Corporation 15620 Halsted Street, Harvey, 111. (Chicago Suburb) Representatives in All Principal Cities Stokers PRODUCTS--Complete line of Stokers and Pulverizing Equip ment for firing boilers (up to 5,000 hp) including Horizontal Compression Feed Stokers, Underfeed Stokers for small boilers and furnaces, Impact and Table Roller Pulverizers, Pulverized Coal Conveying and Feeding Equipment, Burners, etc. UNDERFEED STOKERS FOR AUTOMATIC HOME HEATING Standard models range in capacity from 20 to 90 lb. of bituminous coal , per hour and fit practically any solid-fuel boiler or furnace, old or new. Dual Draft Burner permits efficient combustion of lowest-priced grades of coal. Further economies result from the efficiency with which fuel-feeding is regulated. Hopper is only 25 in. from floor to facilitate filling, each day or so. Except for setting upstairs thermostat, operation is then entirely auto matic. The Whiting Stoker is practically noiseless and odorless. There is no back , .. firing--no ashes (only a few clean, hard. clinkers). Operating cost is substantially less than any other form of automatic heating --a clean, safe stoker which may always be hand-fired in a storm or other emergency, when electric wires may be down. UNDERFEED STOKERS COMMERCIAL USE For either Refractory or Dead Plate Setting--ranging in capacity from 90 to 1250 lb. of bituminous coal per hour. They are designed to fit all types of boilers-- cast iron, locomotive, horizontal return tube, vertical down draft, and brick set. Like the Domestic Models, they are equipped with Dual Draft Burner, per mitting the efficient combustion of lowestpriced grades of coal. Whiting Underfeed Stokers are designed for small industrial plants--warehouses and stores--laundries--dairies--garages-- greenhouses--hotels and apartments--r hospitals--public buildings--public and private institutions--schools, colleges and churches. Their installation reduces fuel expense and operating costs. Less labor is lired, and the boiler room kept cleaner. 1033 V Temperature Control Barber-Colman Company Rockford, Illinois BARBER-COLMAN ELECTRIC SYSTEM OF TEMPERATURE AND HUMIDITY CONTROL AND UNI-FLO GRILLES AND REGISTERS Branches and Representatives Atlanta, Ga. Buffalo, N. Y. Chicago, III. Cincinnati, Ohio Cleveland, Ohio Denver, Colo. Detroit, Mica Dcloth, Minn. Framingham. Mass. Greenville, S. C. Indianapolis, Lnd. Kansas Crrr .Mo. Los Angeles, Calif. Milwaukee, Wa Minneapolis, Minn. Moline, III. New Orleans, La. New York, N. Y. Omaha, Nebb. Philadelphia, Pa. Phoenix, Aan. PirrsauBOH. Pa. Portland, Orb. Richmond, Va. Salt Lake Citt, Utah San Francisco, Calif. Seattle, Wash. St. Loois, Mo. Toledo. Ohio . Washington, D. C. Amsterdam, Holland Oslo, Norwat Sidney, Australia Tokio, Japan Toronto, Canada Winnipeg, Canada Thermostat Motor Voire FEATURES The Barber-Colman Electric System of Temperature and Humidity Control can be applied to any kind of heating, venti lating, or air conditioning installation. Accurate, automatic controls can be fur nished for a single room or an entire building, for an ordinary residence or an ornate city hall, for one radiator or a large and complicated blast system. Suitable apparatus can be provided to handle steam, hot water, warm air, air con ditioning, humidification, cooling--any thing that up-to-date engineering requires. Barber-Colman apparatus comprises fif teen different types of thermostats, twelve different types and hundreds of sizes of motor-operated valves, ten dif ferent types of motor-operated damper controllers, as well as hygrostats and other special equipment and accessories. Barber- Colman control systems are installed and operating successfully in every section of the country. Communications from heat ing engineers regarding control problems will be welcomed. All-Electric--All units operated by electricity, all connections electrical. Low-Voltage--Power used 25-volt a.c. Smaller size wire and less insulation re-' quired. Facilitates installation in new qr existing buildings. . Motor - Driven -- Operating units powered by small electric motors. No actuation by gases or liquids. Minimum Auxiliaries--Few required by all-electric equipment. . Appearance--Neatness and good ap pearance stressed in design. Units occupy minimum space. Variety and Adaptability--Sufficient equipment available to provide proper controls for any heating, ventilating, or air conditioning system. . Low Maintenance Cost--Minimum upkeep work required. Apparatus will' perform dependably without attention. Underwriters' Approval--The Barber- Colman Electric System of Temperature and Humidity Control is listed as standard by the Underwriters' Laboratories. Fig. t. Room Thermostat far wall mounting. Used in residences, offices, theatres, etc. Fig. 'kr Duct Thermostat far insertion in warm air duct o//an systems. Fig, S. Motor-Operated Damper Controller for positioning all kinds of dampers. Fig. 4- Motor-Operated Valve, radiator packless type shown. Fig. 6. Large Motor-Operated Valve for steam mains. , 1034 Fig. 6 Barber-Colman Company Temperature Control GRILLES REGISTERS ENGINEERED AIR DISTRIBUTION OUTLETS Featuring--Aspiration, Diffusion, Directional Flow Grilles--For sidewall, panel, and base board applications. Snap-Lock construc tion. Frame is roughed in after studding is in place. Fin core snaps into frame when decoration is completed. Directional Fins furnished as required. AIR-LITE--Ceiling unit combining air outlet and lighting fixture. Uniform dif fused air flow in all directions. Two sizes. Ceiling Grilles--Air outlet only. UniFlo diffusing fins deliver soft blanket of air. Adjustable volume control. Three sizes. Registers--Damper under spring ten sion. Continuous leak-proof piano hinge. Flexible control chain with positive lock. Spring tension on damper when closed. Tamper-proof key operation optional. Snap-Lock construction. Aspiration -- An unique effect caused by turbulence of Uni-Flo air stream. Entrains surrounding air to im prove circulation. Diffusion--Turbu lence of Uni-Flo air Stream causes thorough mixture with room air and rapid rise of air stream temperature. Directional Flow -- Deflecting fins can be arranged to direct all or any Parts of air stream at various angles up, down or sideways as required by location of outlet. UNI-FLO Fins--Multiplicity of thin fins have a number of valuable and unique features. Diffusers on edges of fins pro duce turbulent, rolling air stream that mixes rapidly with room air. Permissible low supply air temperatures and high discharge velocities result in small duct and grille sizes. "Aspiration"--definitely a Uni-Flo characteristic--induces thorough circulation, uniform temperature through out conditioned space. Long throw of air possible. Deflecting fins provide accurate distribution of air in room. Temperature Control Detroit Lubricator Company Detroit, Michigan, U. S. A. New York, N. Y., 40 West 40th Street Chicago, III., 816 S. Michigan Avenue Los Angeles, Calif., 3251 Wilshire Bivd. Canadian Representative: Railway and Engineering Specialties Limited, Montreal, Toronto, Winnipeg Division of American Radiator & Standard Sanitary Corporation AIR CONDITIONING CONTROLS Solenoid Valve A dependable shut-off for liquid or suction lines in both air-con ditioning and refrigeration. Draws approximately 12 watts during operating period. Furnished with either %2 or 34 in. orifice. See Bulletin 34. No. 67S-R r\ Pressure Control (Model RB-3) Accurately controls low side pres sure. Range 20 in. vacuum to 40 lb pressure. Differential adjustable from 5 to 25 lb. Available in other models to control temperatures. See Bulletin 60. Cabinet Thermostat A high voltage control entirely concealed except for the knob on the outside of the cabinet. Permits integral wiring of a portable cabinet heater or cooler. Posi tively insulated against both radiant and conducted heat. See Bulletin 67. Automatic Expansion Valve Either gas or liquid charged--sensitive, efficient and dependable on either low or high temperatures. Ther mostatic element provides automatic operation. As sures full flow and maximum tonnage. Capacities up to 2 tons sulphur dioxide or Freon. Other Thermostatic Expansion Valves for capacities up to 21 tons on Freon. No. 67S Differential Thermostat Can be furnished in either Northern or Southern range to assure maximum comfort. Designed primarily for tem perature control with room cooling apparatus. It operates on differences in temperature inside and outside. Write for Bulletin 74. ZONE CONTROL No. 691 For proper control of forced air systems, zoning is neces sary. The "Genuine Detroit" Duct Damper Motor No. 431 may be mounted directly on the duct without risk of objectionable noise. The No. 431 controls both fuel and air supply. It is neat in appearance and easily installed. OTHER CONTROLS This Company can also supply you with a full line of. Boiler and Furnace Limit .Controls --Room thermostats both high and low voltage for both heating and cooling--Fan controls--Humidity and Stoker Controls. 1036 Temperature and Humidity Control Julien P. Friez & Sons, Inc., (A Subsidiary of the Bendix Aviation Corporation) Baltimore, Maryland, U. S. A. , Established 1876 Manufacturers of a Complete Line of Automatic Electric Controls for Industrial and Comfort Applications. Also a Complete Range of Recording and Accurate Measuring Instruments for Indoor and Outdoor Applications Humidistats--Human hair elemented, pre eminent in their field. See Bulletin #A. Thermostats--Precision instruments, beauti ful in appearance, high quality. See Bulletin #T. Effectistats--Providing Effective Tempera ture Control with simple heating (or cooling) equipment only. See Bulletin #E. Indicators--Human hair elemented, accurate and reliable, moderate in price. See Bulletin #D. ' Comfortrols--Providing complete Effective Temperature Control where complete year round air conditioning equipment is available. See Bulletin #C. Hytherstats--Humidistat and Thermostat incorporated into a single case. See Bulletin #C. Portable Recorders--Recording re lative humidity, temperature, and running time. Rugged, reliable, ac curate, and moderate in price. See Bulletin #G. ` Hythergraphs--Recording relative humidity and temperature. Precision instruments designed for permanent or semi-permanent installations. See Bul letin #H. ' Round Chart Recorders-- Recording relative humidity and temperature for wall mounting and for local or remote recording. See Bulletin #R. Thermo-Shielded Electric ally-Aspirated Psychrometers --A most accurate instrument for precise measurement of Wet and Dry Bulb conditions. Repre sents 60 years' experience in construction of accurate instru ments. Anemometers--Biram and Direct-Reading Types. Write for full details of the complete Friez line of indicating, recording, and measuring instruments for indoor and outdoor applications. 1037 Temperature Control The Fulton Sylphon Company SYLPHON AUTOMATIC TEMPERATURE CONTROLLING INSTRUMENTS Knoxville, Tennessee Sales Representatives in Principal Cities PRODUCTS Au tomatic Radiator Valves for Room Temperature Control; Space Tem perature Regulators; Unit Heater Regulators; Duct Temperature Re gulators; Damper Regulators; Hot Water Supply Temperature Regu lators; Regulators for the Control of Refrigeration Temperatures, Air Con ditioning Systems, Drinking Water Systems, etc.; Packless Expansion Joints for Heating and Plumbing Risers; Pressure Reducing and Re gulating Valves. GENERAL INFORMATION The Fulton Sylphon Products, listed above and described in the following paragraphs, depend upon the famous Sylphon Metal Bellows for their remark able, trouble-free service and long life. By continuous engineering study and intimate contact with heating and refrig eration problems, this Company has used this efficient, practically indestructible bellows in the development of a line of temperature control and heating special ties known for their outstanding per formance qualities. In attaining and maintaining this enviable position, The Fulton Sylphon Company's plant has been extended until today it is one of the largest in the world specializing in the manufacture of this type of equipment. Every phase of the quality production of Sylphon products from raw materials to the finished product is scientifically con trolled in this plant. At' this plant, a unique testing laboratory is maintained as a proving ground where every Sylphon product is subjected to conditions dupli cating the most strenuous actual service in the field before approval for shipment. It is with the knowledge of these re sources behind the Fulton Sylphon line that engineers prefer, whenever possible, to specify Fulton Sylphon equipment. For they know, by experience that permanent satisfaction-will always be assured. SYLPHON AUTOMATIC RADIATOR VALVES No. 885 Sylphon Automatic Radiator Valve for exposed radiation. (.Globe Type No. 886) Used in place of ordinary radiator valves to provide individual room temperature comfort in both new and existing buildings. Entirely self-contained, self-powered and self-reliant, they require no complicated piping or auxiliary equipment. Types for both exposed and concealed radiation are available. Sylphon Automatic Radiator Valve for Concealed Radiation. Angle Valve. No. 895. Globe Type. No. 896 Sylphon Valves for enclosed .radiators provide the balanced heat control made necessary by the very nature of enclosed radiation. These valves are exclusive in that they provide control at two points, by two bulbs--first, at the cool air inlet at the bottom and, second, at the heated air outlet at the top of the enclosure. Small, neat in appearance, finely finished, conveniently adjustable to the room temperature desired, and faithful in their maintenance of temperature at the set point--these valves answer the demand for an-inexpensive means of providing accu rate, dependable space temperature control in individual rooms, sections or throughout large buildings. Bulletin HVG-255. 1038 The Fulton Sylphon Company - Temperature Control SYLPHON ELECTRIC CONTROL VALVES No. 890 Sylphon Electric Control Valve. (Globe Type No. 891) Similar in appearance and action to Sylphon Automatic Valves, but operated by an electric wall thermostat. These valves utilize as their motor element a "hot bulb" containing a volatile liquid which expands, causing liquid pressure to throttle the valve, when an electric heater coil which surrounds the bulb is energized by the closing of the electric thermostat circuit. This arrangement provides radiator valve control from a remote location, permits the regulation of several radiators from a single thermostat, and permits the inclusion of an electric time switch to govern maximum and minimum tempera tures supplied to a building during working and idle hours, offering zone control of large buildings at a fraction of the cost of conventional motor-operated valve sys tems. Bulletin HVG-519. SYLPHON REGULATORS FOR UNIT HEATERS OR DIRECT RADIATION IN INDUSTRIAL AREAS This instrument is entirely mechanical and utilizes pressure of an expansible liquid in a Sylphon Bellows thermostat element transmitted through flexible tubing to another Sylphon Bellows in the valve, to actuate the packless valve and throttle the steam supply to the room or section of the building, according to temperature desired. No. 7 Regulator may also be installed with a thermostatic switch in the steam supply line between the regulator and the unit heater or heaters when used to control this type of equipment. This switch will then act to cut off the fan motor whenever steam supply is cut off, and will start the motor again when steam is turned on. Bulletin HVG-252. Sylphon Unit Heater Regulators Nos. 9, 9-S and 9-E are similar controls for use with higher steam pressures. No. 9 controls steam supply only. No. 9-E con trols steam supply and operates in con nection with a room thermostat. It may be connected with a thermostatic switch in the steam line to control the fan motor as well. No. 9-S combines within the regulator itself means of controlling both steam supply and fan motor. Bulletin HVG-50. SYLPHON PACKLESS EXPANSION JOINTS The Sylphon Packless Ex pansion Joint was designed to eliminate useless building height, expensive contruction and non-revenue producing space. It prevents costly leaks and repairs, requires no repacking, and because it is always tight, it allows the heating system to operate at full efficiency. Two types, for steam (No. 110), and for water (No. 111). Thousands are in use in many prominent buildings. Write for Bul letin HVG-300. No. UO Sylphon Expansion Joint 1039 Temperature and Humidity Control Johnson Service Company TEMPERATURE AND HUMIDITY CONTROL General Offices and Factory Milwaukee, Wis. Branch Offices in all Large Cities Johnson Temperature Regulating Co. of Canada. Ltd., 97 Jarvis Street, Toronto, Ont. Montreal, Que. Winnipeg, Man. Calgary, 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, and air conditioning installations. A single nation-wide organization devoted to Design, Manufacture and Installation for more than 50 years. Temperature and Humidity Control for every range required in manufacturing and industrial processes. . Room temperature control applied to radiators, unit ventilators, and heat delivery ducts. Johnson "Duo-Stats " to maintain the proper relationship between outdoor and radiator temperatures for groups of radiators or "heating zones." A complete line of devices for automatic control of air conditioning systems, heating, cooling, humidifying, dehumidifying. Automatic seasonal shifting of control cycles. Periodic Flush Systems for intermittent flushing in various sections of a building, reducing load on piping system and insuring economy in use of water. Special bulletins and catalogues on request. Sales Engineers at branch offices in all principal cities. Johnson All-Metal Thermostats Room Thermostat Johnson thermostats, room, insertion, and immersion types, are all metal throughout, no soft or hard rubber parts to deteriorate and become inoperative. Every thermostat precise in construction and thoroughly tested for accuracy, efficiency, and durability. , The Johnson intermediate action thermostat gives a true graduated motion to mixing dampers and valves. It holds them in an intermediate position to maintain the temperature of the room accurately within one deg. above or below the setting of the thermostat, if desired. Johnson "Dual" or Two-Temperature Thermostats The Dual, two-temperature, room thermostat especially adapted for use where various rooms or groups of rooms are occupied when the remainder of the building is not in use. Separate steam mains avoided. The shifting from "day" or occupancy temperature to an economy temperature for "non-occupancy" conditions, accomplished by a switch or Johnson program clock at a central points Push buttons on the thermostat are provided when "occupant control" is desired. Dual thermostats are all-metal and operate valves and dampers gradually to maintain temperature accurately within one degree. Dual Thermostat Johnson Valves Radiator Valve Johnson diaphragm valves are simple and rugged. Seamless metal bellows and heavy spring operate the valve stem. No complicated moving parts. Made in all standard sizes and pattern's. Direct acting (normally open) or reverse acting (normally closed). Three-way mixing and three-way bypass valves. For steam, water, brine, and Freon service. Johnson valves are available, if desired, with diaphragms of special. moulded rubber, super-aged and heat-resistant. 1040 Room Humidostat Johnson Service Company Temperature and Humidity Control Humidostats and Humidifiers The Johnson Humidostat automatically controls the supply of moisture delivered to the air by a humidifier or air washer and maintains a constant percentage of relative humidity. Available in both room and insertion patterns, and with. various types of elements as determined by requirements', controlling within 1 per cent at relative humidity of 95 per cent and 100 deg Fahr if desired. Johnson humidifiers are furnished in steam "grid" type or pan type with copper evaporating pan, brass heating coil, and float control. Air Conditioning Control Summer-Winter room thermostats for operation of valves . and dampers in reverse sequence for cooling and heating. Four-Point Insertion Thermostat Insertion and immersion thermostats in one, two, three, and four-point patterns for operating valves and dampers suc cessively at different temperatures. Remote readjustable thermostats, reset from a distant point by pilot or differential thermostat or by pressure switch. Differential thermostats to maintain desired temperature differences between two points, such as outdoors and treated space. Solenoid air switches, manual switches, static pressure regulators, velocity regulators, operating dampers to regulate flow of air in ducts. The Johnson sensitivity adjustment is an important development in the field of automatic temperature and humidity control for air conditioning. A unique and convenient means of adjusting the sensitivity of Johnson thermostats and humidostats on the job, with respect to the capacity of the conditioning apparatus. Remote Readjustable Thermostat Zone Control Johnson "Duo-Stats" to regulate the flow of heat in a group of radiators constituting a "heating zone" by maintaining the proper relationship between outdoor and radiator temperatures. Process Control Calibrated insertion thermostats for control ling temperature of liquids, air and gases. Mercury extended tube thermostat for remote location of sensitive element. Wet-bulb thermostats for close regulation of humidity. "Record -O- Stats," combination instruments to record and contrql tempera tures. Summer Winter Thermostat Program Clock Tube Thermostat - Record-O-Stat 1041 Johnson "Duo-Stat" Temperature Control GENERAL 1S05 BROADWAY CLEVELAND. OHIO CONTROLS 1368 HARRISON ST. SAN FRANCISCO. CALIF., FOR DEPENDABLE CONTROL OF TEMPERATURE - PRESSURE - FLOW Gas - Oil - Air - Water - Steam Refrigerants Your installations will operate at high efficiency, with dependability and safety, if controlled by GENERAL Automatic Thermostats, Solenoid Valves and Switches. Their fundamental designs are right from an engineering standpoint. Their construction is simple--few moving parts--no pawls or catches to fail--no parts to oil--no corrosive materials to rust or jam. They are manu factured by methods of precision. The result has been an enviable record of field performance. The GENERAL Solenoid The quiet A. C. Solenoid is a GENERAL CON TROLS feature. Its design and simplicity of action have given the solenoid a reputation for dependable year-after-year field service. .. K-10 Magnetic Valve The solenoid is current-failure, incorporating impact- type plungers. Special metal plunger-tube is rolled and sealed ; no threaded joints or gaskets used. Water-proof coils are detachable and termi nal connections may be rotated in any direction for ease of wiring. For Domestic or Industrial Applications Illustrated on this page are the K-10 and the B-50 magnetic gas valves widely used on industrial installations. Among the 19 other GENERAL products you will find the right control for practically any application. The General Controls Co. will gladly help solve any specific problem. Your correspondence is invited/ K-10 Magnetic Valve--For controlling oil, water, air, gas. A two-wire, currentfailure magnetic valve. Its lever action closing with the flow, insures a tight shut-off indefinitely. Will operate at high pressures on either fluids or gases. As in all other GENERAL CON TROLS, the K-10 is entirely free from A.C. hum. B-50 Slow-Qpening Gas. Valve--Electrically operated diaphragm valve having an adjustable opening time of from 5 to 60 seconds. Ample damper power even at low pressures. Uniflow valve . guide provides uniform increase in gas flow'. Current consumption 8 watts. . b-bo Slow Opening Valve Send for New Catalogue This catalog will be valuable to every engineer. Showing the com plete line of GENERAL CON TROLS, it also gives engineering data and wiring diagrams. Write us. Your copy will be sent by ' return mail. 1042 Temperature Control The Mercoid Corporation SOLE MANUFACTURERS OF THE MERCOID SWITCH Chicago, III., 4201 Belmont Avenue. New Yore, N. Y.t 90 West Street. San Francisco, Cali/., 1129 Folsom Street. Distributed and Stocked In Many Cities by the Graybar Electric Co., Inc. COMPLETE LINE OF AUTOMATIC CONTROLS Mercoid Controls have a wide applica tion in both the domestic and industrial fields. They are generally employed for the control of motor-driven automatic heating, refrigeration and air conditioning equipment, electric space or tank heaters, and for numerous industrial applications. Equipped throughout with Mercoid sealed mercury contact switches. Complete Catalog Sent Upon Request adjustment feature, is designed primarily for the protection of automatically fired steam boilers, to pre vent the hazard of fir ing into dry boilers and alsoguard against building up excessive steam pressure. SENSATHERM A sensitive air type thermostat for low or high voltage requirements. Used forv controlling automatic heating, refrigera tion, or air conditioning equipment. Furnished standard for low voltage to operate with the Mercoid Transformer - Relay. It can directly handle 20 watts or less on 110 or 220 volts without a relay. The standard range is 55 to 85 deg F. Other ranges are available. Total dif ferential, 1 deg F (plus or minus deg). Dual Sensatherms avail able for day and night temperature regulation, also for heating and cool ing operations. TYPE V TRANSFORMER-RELAY A low voltage mercury contact relay, which also acts as a transformer inducing low voltage (24 volts) on the pilot circuit. Its construction does away with all hum and chatter. Available for 110 or 220 volts, 60, 50 or 25 cycle. Can also be fur nished as a repulsionrelay for 110 or 220 volts d-c. MERCOID COMBINED PRESSURE AND LOW WATER CONTROL TYPE DA-121 The Type DA-121 Mercoid Low Water and Pressure Control with the new double MERCOID STOKATHERM The Stokatherm System operates the stoker for only the very shortest periods necessary to maintain a minimum fire while the thermostat is in the off position. The firing periods are not at definitely timed intervals or governed by fixed stacktemperatures, but are automatically regulated to meet the variable conditions en countered on each instal lation. If the fuel de livered to the stoker should have a higher or lower burning rate than that formerly used, the Stokatherm System automatically compen sates for its firing period accordingly. Should the fuel become exhausted or the fire go out, the Stoka therm System automatically stops the stoker. This prevents operating an empty stoker and guards against filling the com bustion chamber with unburned fuel. Warm Air Furnace Controls--Type M-51 is used to protect warm air furnaces from overheating where automatic heating equipment is used. Type M-53 is to con trol fans or blowers to prevent operation unless the furnace is warmenough to deliver heat. Adjustable mount ing flange and a graduated tempera ture dial is provided. Also furnished with long -bi-metal stems for bake-ovens and industrial applica tions. Temperature and Air Conditioning Control Minneapolis-Honeywell Regulator Company Executive Offices: 2711 Fourth Ave. So., Minneapolis Akron Allentown Atlanta* Baltimore Birmingham Bismark Boston* Buffalo* Burris Chicago* Cincinnati Cleveland* Factories: MINNEAPOLIS MINN., and WABASH. IND. Branch and Distributing Offices: Columbus Dallas Denver' Detroit* Duluth* East Orange* Evansville Fort Wayne Grand Rapids Hartford* Haverhill, Mass.* Houston Indianapolis* Jackson, Mich. Kansas City* Little Rock Los Angeles K .*Louisville, y Milwaukee* Minneapolis--St. Paul* Newark - New Orleans New York* Oklahoma Crrr Omaha* Peoria* Philadelphia* Pittsburgh* Portland Providence* Reading St. Louis* Salt Lake City . San Francisco* Scranton Seattle . Springfield, Mass.' Syracuse* Toledo Tulsa Washington, D. C. Wichita Worcester, Mass. York, Pa. Youngstown In Canada: Montreal, Toronto, Calgary In Europe: Amsterdam, Holland THE MODUTROL SYSTEM OF AUTOMATIC CONTROL for Heating, Ventilating and Air Conditioning The Modutrol System designation is applied to any combination of Minneapolis-Honeywell Automatic Electric Controls or Selfcontained Automatic Valves used to govern the operation of air con ditioning or heating systems other than the small domestic instal. lations. Controllers of various types actuated by positive means and, in turn, connected to electric power units governing valves, dampers, etc., present a new conception of dependability and ease of instal lation not heretofore possible. In the Modutrol System the wellknown dependability of electric switches and motors, the permanency of electric wiring, the flexibility of self-contained units and the accessibility of each and every portion of the equipment represent just a few of many advantages offered in this modern'means of air conditioning control. PROVIDES TRUE MODULATION Viewed from the performance standpoint, the Modutrol System offers true modulation of the temperature, air flow and humidity. True modulation means automatic proportioning of heat, cold, air flow or humidity in exactly the required amount to offset changes in the heat loss or relative humidity. INCLUDES SUPPLEMENTARY EQUIPMENT Supplementing the modulating controls is a wide variety of on-andoff or two-position motors, controllers and valves, thus making the Modutrol System extremely flexible as to the selection of control equipment to produce the desired results. APPLICABLE TO ANY FORM OF AIR CONDITIONING OR HEATING Any form of air conditioning or heating, from systems for the home to systems for the skyscraper can be controlled by the Modutrol System. While the principle of the Modutrol System in its use of electrical or self-contained units differs from the principles in vogue in years past, there is nothing untried or uproven in either design or application. See also Page 9S0 .1044 Minneapolis-Honeywell Temperature and Air Conditioning Control RESULT OF A HALF CENTURY'S EXPERIENCE Fifty years of concentration upon temperature control problems has built up within the Minneapolis-Honeywell organization the knowledge, technique and engineering ability which have produced the Modutrol System as well as the comparatively simple domestic control systems. Turin Thermostat REDUCES COST OF HEATING OR AIR CONDITIONING SYSTEM OPERATION In new buildings or old, a lowering of operating costs, and an immense improvement in the comfort delivered, can be accomplished by considering the control system as an integral part of the heating system. In fact, automatic control systems, today, cannot be con sidered as accessories to the heating systems. ENGINEERING SERVICE The Minneapolis-Honeywell Automatic Control engineer is at your service at all times. He will be glad to furnish you with recom mended control layouts and cost estimates. He is trained to recommend control results before installation of equipment and to produce control results after the installation of equipment has been completed. Humidity Controller COMPLETE INSTALLATION SERVICE " Minneapolis-Honeywell Branch Offices and Distributors are equipped to make the complete installation of the Modutrol System for cont rol of Air Conditioning or Heating installations. Thoroughly trained men are also available to supervise, adjust, or service the control equipment if the purchaser prefers to make his own instal lation of controls. RESPONSIBILITY FOR ENTIRE CONTROL SYSTEM The Modutrol System and its supplementary equip ment is so complete that the Minneapolis-Honeywell Regulator Co. is equipped to assume the entire re sponsibility for any control installation, thereby elimi nating the difficulties and misunderstandings which the division of responsibility may create. Modutrol Motor TYPICAL SPECIFICATIONS A complete set of typical specifications covering automatic control systems for use in heating, venti lating, and air conditioning is available for use by engineers and architects. DESCRIPTIVE LITERATURE Catalogs arranged according to the following subdivisions are available upon'request: 1. The Modutrol System. 2. Air Conditioning Controls. 3. Oil Burner Controls. . 4. Gas Heating Controls. 5. Stoker Controls. 6. Industrial Regulator Controls. 7. Refrigeration Controls. :.` 8. Complete Condensed Catalog. In addition to this literature, complete data, sheets are available, including technical information on all equipment in the Modutrol System which is of prime interest to the engineer. These pages will be furnished on request. 1045 Minneapolis-Honeywell Temperature and Air Conditioning Control TYPICAL MODUTROL SYSTEMS The Modutrol System is composed of many individual units of control which may be used separately or in any combination properly coordinated to produce the required results. . The Modutrol Systems outlined on the succeeding pages are only a few of the many types available but will serve to illustrate the extreme flexibility of the Modutrol System and its adaptability to the needs of the individual installation. Ckronotherm ZONE CONTROL OF HEATING SYSTEMS It is widely recognized that proper temperature control in larger commercial buildings, stores, office buildings, churches, schools, factories and warehouses, and similar structures must be based on heating needs of various parts of the building, and that these needs vary due to different conditions in parts of the same structure. North exposures require more heat than south exposures--similarly those parts of the building subject to the.wind effect need more heat than those not so exposed--and where the sun shines on a part of the build ing less heat is needed than is required in parts not subject to the heat given off by the sun. The Modutrol System makes provision for temperature control which takes these factors and others into proper consideration. Thus each building may be divided into suitable zones based on exposure, occupancy and time requirement and the delivery of heat is adjusted to the requirements of each zone. Modutrol Zone Control prevents tem perature fluctuations and thus prevents wasteful delivery of steam where and when it is not needed yet maintains comfort conditions for the occupants. Modutrol System Control installed in either new or old buildings throughout the nation have a notable record in the reduction of heating costs--many installations saving in excess of 20 per cent of the annual fuel bill. ' ,, The Weatherstat MaUfrued Zone Volte THE WEATHERSTAT The combined effect of all four outside weather factors which are temperature, wind direction, wind velocity, and solar radia tion determines the heat loss and consequently the heat require ments for any building. The Weatherstat is the outside control which responds to all of these four weather factors and the reaction of the Weatherstat to these outside conditions enables it to immediately compensate for outside changes by supplying more or less heat as required to the building or zone it controls. This results in high efficiency and economy of operation. The fuel savings it effects make the Weatherstat an ideal medium for modernization as well as for new buildings because an investment in the Weatherstat is self-liquidating, and insures the benefits of tenant satisfaction. The Weatherstat consists of a mass of iron shaped to contain a thermostatic element with the necessary electric contacts, and is arranged to house a small electrical heating element within the mass. The heat-release from the electrical heating element is designed to, and by an adjustable resistance can be made to, bear the same relation to heat losses from-the control housing as the heat release from the heating fixtures within the building bears to heat losses of the building. Being subject to the same weather influences, and the same relative rate of heating and cooling, the temperature throughout the zone or building and the temperature with in the control housing will maintain a fixed relationship, and the temperature in the control housing can be used as the pilot temperature for the zone or building. In reality, therefore, the Weatherstat is equivalent to a room out-of-doors, with the same heat loss ratio as the zone or building which it controls. 1046 Minneapolis-Honeywell Temperature and Air Conditioning Control Line Voltage Thermostat UNIT HEATER CONTROL The nature of the unit heater method of delivering heat makes automatic controls an absolute essential if any degree of satisfaction and economy of opera tion is to be obtained. Minneapolis-Honeywell controls meet the re quirements of all types of installations. The simpler of these is satisfied by the mercury switch type of line voltage thermostat, while complete and precise control can be obtained through the use of low voltage thermostats, limiting devices, motor valves, and relays. These complete systems of control so govern the unit heater as to make it not only com pletely automatic, but highly satisfactory and decidedly economical in operation. Unifan Control Refrigeration Pressure Control REFRIGERATION CONTROLS A complete line of refrigeration controls of pressure and temperature type are aivailable for the control of refrigeration equipment. Thermostats of the self-con tained and remote type with a wide variety of temperature ranges offer solu tion to any refrigeration temperature con trol problem. The scope of pressure ranges in the pressure controller embraces any problem of refrigeration pressure control. Refrigeration Temperature Control UNIT VENTILATOR CONTROL The desirable heating and. ventilating pro perties of the unit ventilator are greatly enhanced by the Modutrol System of auto matic control applied to the heating coils, mixing and/or fresh air dampers. All makes of unit ventilators can be purchased with Modu trol equipment incorporated or this system of control may be applied to new or old instal lations in the field. Complete sets of Modutrol Mqtors, temperature controllers and damper linkage plus steam valves where necessary are available.' The economy of operation under the Modutrol System is a distinct advantage in addition to the healthful comfortable tem perature control result which it produces. Engineering assistance in the selection and installation of the Modutrol System to unit ventilators is available at all Minneapolis- Honeywell offices. The typical unit ventilator shown at the right is provided with control for final room temperature through the modulation of mixing dampers actuated by a Modutrol Motor under influence of a modulating room thermostat. The intake damper actuated by a two position Modutrol Motor opens to admit outdoor air on starting of the unit ventilator fan and moves to ; the closed or recirculation position on interruption of current to the fan motor. Often . the intake dampers of a multiple unit ventilator installation are controlled in groups from manual switches on a central control panel either simultaneously with or indepen dent of fan motor operation. Mirmeapolis-Honeywell Temperature and Air Conditioning Control CONTROL OF CENTRAL FAN SYSTEMS Modutrol System Controls can be selected for and applied to any of the innumer able arrangements of central fan systems from the simple system used only for venti lation to the most complex air conditioning system involving all varieties of preheaters, reheaters and booster heaters, fresh air, recirculated air and mixed air ducts and dampers, face and by-pass dampers, humidifiers and dehumidifiers, coil or spray coolers, etc. Control may be applied in almost any degree of automatic operation from various con trollers of the thermostatic room or duct type, humidity sensitive type or those actuated by pressure or time. In these systems electric motorized or Modutrol Valves or Modutrol Motors actuating dampers respond to the demands of the controllers to which they are electrically wired. Each motorized valve or damper motor is selected for its particular function and is a self-contained unit. The wide selection of equipment in the Modutrol System insures the ability of the central fan performance in a satisfactory manner and yet provides extreme flexibility and minimum cost in both installation and maintenance while providing the inherent dependability of electrical equipment. In either new construction or old the inter-connection of the controllers and the controlled equipment is simplified to the running of electrical wiring the majority of which is low voltage. CONTROL OF AIR CONDITIONING SYSTEMS Whether air conditioning is accomplished in unit conditioners or central fan con ditioning systems, the Modutrol System will provide an accurate and reliable control. When required the Modutrol System provides for automatically adjusting the temperature of the cooler area in relation to outdoor temperature, and for the modu lation of outdoor air and return air dampers so as to use outdoor air for either heating or cooling whenever possible. , The following typical examples will illustrate the flexibility of the Modutrol System in its application to air conditioning systems. Figure 2 illustrates a system of controls for a typical air con ditioning sys tem. Operation of the controls is as follows: 1. In winter the temperature con troller at the intake of the preheater is set at some tem perature control point above freez ing and regulates the Modutrol Motor which in INTER turn determines the relative positions of the outdoor and SUMMER 0W- POINT CONTROLLERS' return air dampers so as to deliver air to the conditioner at this prede FIGURE 2 termined tempera ture. A manual - switch provides for setting the dampers at any desired position in summer and also in winter if preferred.- 2. The winter dew point controller regulates the flow of steam to the preheater through the operation of the Modutrol Motorized valve so as to deliver air from the sprays at a predetermined winter dew point temperature. In winter the Motorized Three-Way Mixing Valve'will be automatically placed in the position which will provide all recirculated water and no cold water to the sprays. ' . 3. The summer dew point controller is set at a higher temperature control point than the winter dew point controller. This arrangement, therefore, provides for automatic change-over as the load changes from heating to cooling, or from cooling to heating. \ The summer dew point controller regulates the proportions of recirculated and cold water to the sprays through the operation of the Motorized Three-Way Mixing Valve so as to deliver air from the sprays at the predetermined summer dew point temperature. . 4. The temperature controller in the return air regulates the position of the reheater face and by-pass dampers delivering more or less air through the reheater coils as the heat requirement increases or decreases. The steam flow to the reheater coil is modulated by a Modutrol Motoi Valve operated by a dual control switch on the Modutrol -Motor operating the face and by-pass dampers. This combination provides an accurate and reliable.control of the return air temperature and the temperature controller in the delivered air prevents the air at this point from falling below a predetermined temperature. 1048 Minneapolis-Honeywell Temperature and Air Conditioning Control COMPENSATED AUTOMATIC CONTROL The demand for increased efficiency in the operation of Air Conditioning and Heating Systems has imposed new functions upon the component parts of these systems. Compensated con trol of temperature, relative humidity, pressure, and combina tions of these factors provide these new functions, and the ease and accuracy with which it is accomplished by the Modutrol System has made its use a practical necessity. The following examples of compensated controls illustrate a few of the many possible variations: 1. Compensated Dry-Bulb Control. The outdoor temperature is measured and automatically determines the inside dry-bulb temperature control ac cording to any predetermined schedule. Compensating Controller Compensated dry-bulb temperature control is accomplished by the use of an outdoor compensator and an inside return air temperature controller or room thermostat which in turn operates the conditioning equipment. ' 2. Effective Temperature Control. The indoor relative humidity is measured and automatically determines the inside dry-bulb temperature control point according to a predetermined schedule which will result in a fixed effective temperature. Effective temperature control is accomplished by the use of an inside relative hu midity compensator and an inside return air temperature controller or room ther mostat which in turn operates the conditioning equipment. 3. Compensated Effective Temperature Control. The outdoor temperature is measured and automatically determines the inside effective temperature control point. The inside relative humidity is then measured and automatically determines the inside dry-bulb temperature control point. Both of these determinations are made according to any predetermined schedule. Compensated effective temperature control is accomplished by the use of an outdoor temperature compensator, an inside relative humidity compensator and a return air temperature controller or room thermostat which in turn operates the conditioning equipment. 4. Compensated Relative Humidity Control. ... The outdoor temperature is measured and automatically determines the inside relative humidity control point in order to prevent frosting on the windows according to any predetermined schedule. Compensated relative humidity control is accomplished by the use of an outdoor, compensator and an inside relative humidity controller which in turn operates the means for adding moisture to the controlled space. ` CONTROLS FOR RESIDENCES - The need for reliable and accurate temperature control systems for residential heating plants is greater today than ever before. This type of heating plant has developed from the simple system of yesterday to the complex one of today, involving automatic firing and in many cases all year air conditioning equipment. Successful performance of such a heating system depends upon the coordination of its several functions into a definite program of operation. Occupancy comfort, therefore, depends upon properly synchro nized control that the home owner has neither the skill nor the patience to give. The home owner must of necessity depend more and more upon an adequate control system for safe and economical operation of his heating system. , For the small manually fired coal heating plants, there are simple damper control sets of thermostat, limit control and damper motor. For the more elaborate heating systems, there are control systems that coordinate functions of heating, air circulation, humidification and cooling into a definite program of operation. For the large heating systems there are control systems for zone control, humidity control and compensated temperature control by which the inside temperature factors are matched against the outside weather variables. Supplementary controls are available for existing control systems that increase "user satisfaction'' and operate.the heating equipment with increased economy, safety and convenience. 1049 Temperature and Humidity Control The Powers Regulator Co* 45 Years of Temperature and Humidity Control Offices in 43 Cities--See Your Phone Directory General Offices and Factory: 2719 Greenview Ave., CHICAGO; General Eastern Office: 231 East 46th Street, NEW YORK; 1808 W. Eighth Street, LOS ANGELES; The Canadian Powers Regulator Co., 106 Lombard St., TORONTO, ONT. PRODUCTS--A very complete line of compressed air operated and selfoperating temperature, humidity and air flow controls for automatically regulating heating, cooling, ventila ting and air conditioning systems and industrial processes. A complete line of self-operating and compressed air operated valves and regulators made for: Controlling steam heated hot water heaters, and submerged type heaters; and for auto matically mixing hot and cold water or steam and cold water delivering a mixture at a predetermined tem perature. Dial Indicating and Recording Thermometers. High pressure steam traps and pressure reducing valves. The Powers Regulator Co. - Temperature and Humidity Control Powers Compressed Air Operated Apparatus 1050 POWERS ENGINEERING SERVICE As the accurate performance of a heat ing,' cooling, ventilating or an air condi tioning system, or an industrial process is so dependent upon its automatic control equipment, and as the cost of such control is but a fraction of the entire system, the use of the proper type of regulation is always Sound economy. when each installation is being planned. Forty-five years of experience in fur nishing and installing temperature and humidity control for every conceivable purpose in all types of buildings has given us a wealth of experience from which you can draw in selecting the proper type of control for any purpose. To secure.the maximum return on the in CATALOGS AND BULLETINS de vestment in automatic control equipment, scribing any or all of our products fur it is exceedingly important that proper nished upon request. Phone or write our selection of control apparatus be made nearest office. See your phone directory. 1051 Temperature Control National Regulator Co. 2311 Knox Avenue Chicago, Illinois Manufacturers and Contractors Complete Systems for Control of Temperature, Humidity, Ventilation and Air Conditioning. Metaphram Damper Regulators for Domestic Heating Boilers and Tank Heaters. A-Jacks High Pressure Steam Damper and Com bustion Control. . A National Control System for temperature, hu midity, ventilation or air conditioning comprises coordinated equipment easily understood by local operating engineers. Each system is planned to meet the requirements of the individual building to assure proper regulation. National Thermostats.(Room Type)---Air operated; simple, two-temperature and compound types for direct radiation, direct radiation ' and unit ventilating ma-. chines, straight blast heating, ventilating fan units and dampers. . National Thermostats (Duct Type)--Air operated;, for ventilating duct or blast heating control and hot water tanks. '\ National Thermostats (Industrial) for control of industrial and process temperatures. Metaphram Valves--Air operated; for direct radia tion, steam lines, hot water tanks, humidifiers and ' accumulator control. Metaphram Dampers--Air operated by Metaphram motors; for accurate automatic control of ventilation and blast heating. Built in round, double or louvre types, of black or galvanized steel or special metals. National Control Boards--Located in engineers room or central place for remote or zone control of pneumatic or electric-pneumatic switches in con nection with two-temperature and zone control systems . under manual or time-clock operation; operating valves or steam lines, radiation, or ventilating fan units and dampers. \ National Air Compressors--Self-contained, auto matic units for unfailing operation of National ap paratus and equipment. Metaphram Damper Regulators for all domestic hot water or low pressure heating boilers, gas, oil or coal fired. A-Jacks Control for high pressure boilers (15 lb to 300 lb pressure) giving synchronized control to boiler pressure and fuel consumption. Catalogs and Bulletins--Thoroughly illustrated bulletins are available on all products. Engineering assistance will be rendered without obligation. 1052 Valoes. Air The Dole Valve Company Main office and Factory: 1901-1933 Carroll Avenue, Chicago, 111. Albant, N. Y. Atlanta, Ga. Baltimore, Md. Boston, Mass. BurrALo, N. Y. Butte, Mont. Cincinnati, Ohio Branch Offices and Representatives Cleveland, Ohio Pallas, Texas' Denver, Colo. Detroit, Mich. Milwaukee. Wis. Minneapolis, Minn. Moline, III. New York, N. Y. Oklahoma Crrr. Okla. Philadelphia, Pa. St. Louis, Mo. Greensboro, N. C. Indianapolis, Ind. Los Angeles. Calif. Salt Lake Crrr, Utah San Francisco, Calif. Seattle, Wash. Spokane, Wash. Toronto. Ont., Canada Wilkes-Barre, Pa. Winnipeg, Man., Canada DOLE AIR VALVES AND BRASS PRODUCTS A Complete line of thermostatic and hot water key air valves Patents have been applied for on all thermostatic type valves No. 101 Dole Econ-O- Vac Valve: Straight Shank--Ji-in. I. P. T. Male,J^-in. 'I.P.T. Female. Bellows operated vacuum seal. Quick venting. Chrome plated--popular price. No. 6B Dole Vacuum Valve: Straight Shank--%-in. I.P.T. Male, %-in. I.P.T. Female. Our leading quick venting vacuum valve. Bellows oper ated vacuum seal. Extra No. 101 No. 100 Dole Econ-O- Vac Valve--Bellows oper ated vacuum seal. Chrome plated--popular priced. No. 1933 Dole Air Valve: Angie Type-- Popularly priced. Attract ively modern in appearance. Bright nickel finish. No. 1933 Dole Air Valve: Straight Shank-- Ys - in. I.P.T. J-i-in I.P.T. _ %-in. I.P.T. Male, j^j-in. I.P.T. Female. Economical in cost. Quick venting. Bright nickel plating. . quick venting. Chrome plated. . No. 2B Dole Vacuum Valve--Our leading vacuum valve. Fool proof construc tion. Non-adjustable. Bel lows operated vacuum seal. Chrome plated. No. 3A Dole Quick Vent Air Valve: Straight Shank--K-in. I.P.T. No. 3B Dole Quick Vent Air Valve: Straight Shank--M-in. I.P.T. ; No. 3C Dole Quick Vent: Straight Shank-- J-in. I.P.T. Male, %-in. I.P.T. Female. No. SB No. 100 No. 1. Dole Syphon Air Valves--Our leading sy phon air valves. Sturdy con struction. Modern de sign. Vents freely, h ro m e Our leading quick vent valves. Extra large venting ports. Chrome plated. Reasonable prices. The Dole Hot Water Key Air Valve (No. 10)--These valves (not illustrated) are packed two dozen in a box. Four keys included in each ' No. 19SS--Angle No. 19$$--Strailht Shout No. SC Write for Prices and Discounts 1053 No.l Y Valves, Air Anderson Manufacturing Co. Cambridge, Mass. Manufacturers of. VENT-RITE Air Valves Pioneers of Balanced Radiation--Since 1932 VENT-RITE RADIATOR AIR VALVES VENT-RITE Valves can be regulated to meet the venting requirements of any radiator . . . By means of an 'exclusive type of variable venting orifice," which provides an unlimited selection of Vent Ports, the distribution of steam in one-pipe systems, is positively controlled. VENT-RITE Valves will balance the resistance opposing distribution of steam in a one-pipe job so that there are no lagging radiators. The vent ing capacity can also be restricted at desired points, to prevent overheating in spots. ' When installed on a thermostatically controlled heating system VENT-RITES can be so set as to allow all radiators to receive the desired amount of heat before the thermostat shuts off. VENT-RITE Valves can be taken apart with the use of an ordinary strap wrench and cleaned. All valves have a conventional union coupling with a heavy gasket which makes the joint leak proof. The adjustment feature is not con spicuous and will not be tinkered with. A wire-like tool is required to set venting rates, and once set by the heating contractor, they stay set. VENT-RITE Valves are made in both vacuum and non-vacuum types. The con . struction of the vacuum type does not depend upon a ball or disc check to maintain vacuum in a system. This is accomplished by a sensitive and positive acting bellows, internally subjected at all times to atmospheric pressure which elongates the bellows, and closes the vent when the internal pressure in the valve is less than the atmospheric pres sure. This pressure differential causes the valve to close, thereby perfecting an inner vacuum seal. . VENT-RITE Radiator Air Valves are noisless in operation, positive in action and seal by float action against water. They close thermostatically under temperature and will not leak or sputter. All parts are made of the best material suitable for valves of this type. The valve pins are of nickel silver. The base is made of a brass drop forging. They are attractively finished in chromium plate. VENT-RITE Valves are guaranteed against defective workmanship or material. VENT-RITE BALANCER The VENT-RITE Balancer is designed for installation on automatically fired steam heating systems equipped with VENT-RITE Vacuum Valves (No. 2- I.V.S.) .... Used in conjunction with these air valves, it provides a means for controlling the distribution of steam at every cycle ... It also makes possible the utilization of the advantages of a non-vacuum system plus controlled distribution and the advantages of a vacuum sys tem--and eliminates.the objectionable features of both. In the operation of one-pipe systems this "balancing unit" brings about a far greater heating efficiency and fuel economy than has heretofore been possible . . . Essentially, the VENT-RITE Balancer creates an entirely new steam heating system and insures Balanced Radiation on every heating cycle. The VENT-RITE Balancer is installed on one of the mains and is electrically con nected with the unit operating the steam supply and automatically operates in con junction with the heat control. 1054 Anderson Manufacturing Co. Valves, Air Anderson Manufacturing Co. Cambridge, Mass. Manufacturers of VENT-RITE Air Valves Pioneers of Balanced Radiation--Since 1932 THE VENT-RITE LINE No. 1 AUTOMATIC NON-VACUUM No. 3 STRAIGHT SHANK NON-VACUUM Ys in. side vent for radia tors. Variable venting capacity. Come-apart con struction. Float seal against water. Closes thermo statically under tempera ture. No. 2-IVS VACUUM Yi >n. side vent for radia tors. Inner Vacuum Seal. Variable venting capacity. Come-apart construction. Float seal against water. Closes thermostatically under temperature. Y\ in. bottom outlet. For risers, mains and convec tion type radiators. Float seal against water. Variable venting capacity. Comeapart construction. Closes thermostatically under tem perature. No. 4-IVS VACUUM J4 in. bottom outlet. For risers, mains and convec-. tion type radiators. Inner Vacuum Seal. Variable venting capacity. Comeapart construction. Float seal against water. Closes thermostatically under tem perature. No. 6-IVS VACUUM Yi in. bottom outlet for risers, mains and con vection type radiators. Inner vacuum seal. Maximum venting ca pacity Ys in. diameter hole. Come-apart con struction.1' Float sea! against water. Closes thermostatically under temperature. STRAIGHT, SHANK NON-VACUUM Yl in. bottom outlet. For risers, mains and con vection type radiators. Float seal against water. Maximum venting ca pacity Ys in. diameter __ hole. Come-apart con struction. Closes ther mostatically under temperature. VENT-RITE BALANCER A solenoid operated valve for automatically controlled steam heat ing systems . . . Pro vides controlled dis tribution :of heat on every cycle . . . Pro vides quicker venting on mains . . . Provides complete Btu transfer from heat supply unit to radiators . . . % in. bottom outlet. For use only on 110 Ylt9-- 60 Cycles A.C. " 1055 Valoes Foster Engineering Go. 109-113 Monroe Street . Newark, N. J. Fifty-six Years Experience in Designing, Manufacturing and Applying Automatic Valves to meet all Classes of Control Service on Steam, Liquids and Gases. Standard and Special Construction T Valoes BRONZE - IRON - STEEL VALVES - SINCE 1864 Mechanical Rubber Goods Principal Stores and Offices: 80 White Street, New York, N. Yi; 524 Atlantic Avenue,Boston, Mass.; 133 N. Seventh Street, Philadelphia, Pa.; 822 Washington Boulevard, Chicago. III.; 510 Main Street, Bridgeport, Conn.; (Office and Factory). Jenkins Bros., Limited: Montreal, Que., (Works, Head Office); London, W.C. 2 Class 34G Pressure Regulator--Single bevel-seated (strainer protected), pilot operated, for single-stage reduction on steam or air for initial pressures up to 900 lbs, 750 F T.T. Maintains a constant delivery regardless of fluctuations of initial pressure or volume of flow and is adapted for deadend service. Type 34G8 constructed with large diaphragms for delivery pressure 0 to 15 lbs. Sizes Yi in. to 12 in. Bronze, semi and east-steeli Type 34U Pressure Regulator--Direct Acting Piston Operated for variable initial pressures up to 300 lbs, 160F T.T. on water or air; adapted for deadend service. Special construction to meet higher pressure. Several types of pilot or direct-acting diaphragm actuated for low delivery pressure and intermittent service. All types have renewable seat discs. Sizes Yz in. to 12 in. Bronze and semi-steel. Class 35A1 Pressure Regulator--For general service on steam with fairly constant initial pressure up to 250 lbs and for delivery pressure between 1 and 150 lbs. For deadend service. Maintains constant delivery pressure. Sizes Yz in. to 10 in. Bronze, semi or cast-steel body. Note accessibility of springs. Class 35B2 Pressure Regulator--For service on steam in apartments, office build ings, etc. Initial pressures up to 250 lbs and constant delivery pressures 0 to 50 lbs. Direct acting, double-seated type (not adapted for deadend service), for variable initial pressures and volume. Sizes Yz in. to 10 in. Bronze, semi or cast-steel body. . Temperature Regulator--Pilot operated, self-contained, single-seated regulator for deadend service. Maintains temperatures of gases or liquids within 1F . Pressures 10 to 200 lbs. Sizes Yz iii. to 3 in. Larger sizes to 8 in., double-seated. Type 34T2, direct- acting, double-seated (not adapted for deadend service) for 0 to 125 lbs. Sizes Yz in. to 6 in. Bronze and semi-steel body. . Float Valves--Very sensitive valve for hot or cold water service, being actuated by the pressure in the supply line. Sizes range from, Y.in. to 8 in. Angle and Globe. Several types made with piston and stem loosely coupled, adding direct-acting feature. Bronze and semi-steel body. OVER 500 DIFFERENT JENKINS VALVES COVER EVERY HEATING AND AIR CONDITIONING NEED - To adequately describe the complete Jenkins line of valves requires a Catalog of more than 300 pages. There are over 500 - different types and patterns of valves that bear the trusted "Diamond" trade mark.. Practically speaking, Jenkins can furnish any valve that you may require for plumb ing, heating, air conditioning, general industrial or engineering service. General Classifications of Jenkins Fire Line Valves. Quick-opening and Self-closing Valves, Needle Valves, Y Valves. ., Other Jenkins Products Are ;-- Colored Valve Wheels with or without service markings molded in relief letters. Composition Valve Discs exactly suited to service conditions. Sheet Packing. Gas kets. Moncrieff Scotch Gage Glasses. ' Valves Include--Bronze Valves fitted CONSULT THIS HELPFUL BOOK with Jenkins renewable composition disc. This 307 page Jenkins Bronze Regrind-Renew Valves with bevel Catalog not only gives and plug type seats. Bronze Gate Valves. . complete details on over Iron Body Valves fitted with Jenkins 500 Jenkins Valves, but renewable composition disc. Iron Body also it has a large section - Regrinding Valves. Iron Body Gate of engineering data and " Valves with solid wedge and double disc practical information parallel, seats. All-Iron Valves. Cast about valves and lay Steel *Gate Valves and Swing Check outs. Make sure you , Valves. Electrically and Hydraulically have a copy, including " Operated Gate Valves. Radiator Valves. the new Supplement "B." JENKINS VALVES ARE SOLD BY MOST GOOD SUPPLY HOUSES 1057 / Valoes New York Air Valve Corporation Since 1898 Chicago Boston Detroit St. Louis Cleveland Pittsburgh Orifice Control Air Valves 611-621 Broadway, New York Vacuum Type Orifice Control Air Valves "CONTROL BY VENTING" The NYAVCO Orifice Control Air Valve herewith illustrated provides through metered orifice disc an accurate medium for con trolling the speed of air elimination from radiators--thus deter mining the volume of entering steam; making any one pipe steam job a controlled heat job. This "Control by Venting" feature is secured by using any of the six measured positions on the disc--as indicated in the sketch on this page--from the full opening as noted on the 0.096 position, then by graduations of 10/1000ths of an inch through 5 other positions to 45/1000ths.' The full opening or 0.096 position has an area approximately 5 times as great as the 0.045 position and the intermediate sizes have areas which are roughly 4-3-2 and 1M times as great. On intermittent heating (Oil Burner, Stoker, Gas fired Boiler) installations the valve is virtually a neces sity as it assures a proportionately equal steam distribu tion regardless of size of radiator or its distance from Patent Pending , the boiler. With proper setting of the control disc the largest or most distant and the smallest and nearest radiator will . heat simultaneously. The valve cap locks the disc in . after adjustment is secured--positively preventing tampering. No sealed floats--Note the bimetallic construction of the operating parts which preclude the possibili. ties of injury to the factory adjustment. The open ' inner float prevents ejection of water into room in "case of flooding. .NYAVCO, distinct in its own field--does not have a sealedfloat and the highest pressure possible cannot injure the working parts of the valve. Due to its shock proof construction and its "control by venting" feature it is invaluable on convector type radiators. Made in both venting and vacuum types. , All NYAVCO Valves are also Made in Vacuum Type NYAVCO is Also Made in in. Straight Male; M in. Straight Male for risers, coils, direct and indirect radiation. _. . All M in. valves have % in. female tapping. % in. Straight Male for convector radiation, unit heaters, blast heaters, etc. % in. StraightrMale fpr quick vents, unit heaters, blast heaters, etc. DISC SHOWING 6 DIFFERENT POSITIONS,FROM.45/1000PARTIAL OPENING,TO.06/ioootti COMPLETE OPENING 1058 Ventilators, Roof The Burt Mfg. Co. VENTILATORS - OIL FILTERS - EXHAUST HEADS AKRON, OHIO, U. S. A. Representatives in All Principal Cities Burt "Foirst-Aire" Fan Ventilators Dimensions -- Weights -- Size Ga. Inche Galv. Oz. Cop per Net Wt Lbs. Overall Overall Dia. Height Inches In -* M otor"' Free Air H.P. R.P.M. cTJT 8 12 30 36 42 48 22 16 82 22 16 99 22 16 104 20 . 18. 125 18 151 18 170 18 20 347 24 483 16 24 625 16 24 798 21 25'/z 27'/z 30 39 52'/2 60 69 7'/z 31'/. 35 36 VH/z 43 50 58 64 72 80 i/ro 1/10 1/10 1/10 1/6 1/6 1/3 1/2 3/4 3/4 1725 1725 1725 1725 1)40 1140 860 86a 675-675 690 1200 1850 2440 2990 4300 6350 10600 11130 14500 Head- -High Efficiency, Low Resistance. Motors--Totally Enclosed--Fan" Duty --Vertical, Ball Bearing--Class 1, Group Motor Mounting--Rubber Cradled-- D optional, Single or Multi-Speed, 110 V., Secure. 1 Ph., Standard on jja and H.P.--220 Types--Standard--Heat Resisting-- V., 3 Ph. on larger sizes. Other Power Acid Resisting--Static Pressure. Characteristics optional at slight delivery delay. Burt High Efficiency Cone Damper Ventilator An examination of the following typical capacities will indicate that this unit type gravity ventilator has been engi neered to move large quantities of air under all conditions. Large, unresticted outlet openings in the head, the diameter and height of windband and the inverted Cone Camper are factors contributing to its efficiency. When used with patented Spring Clip and Fusible Link is approved by - Underwriter's Laboratories, Inc. Dimensions -- Weights -- Capaci ties Size--Inches. 10 12 14 -16 18 20 24 30 36 42 48 54 66 72 Ga. Calv......... Oz. Copper.... Net Wl--Lbs.. O.A. Dia.--In.. OA. Ht.--In... Cap.--C.F.M.*, __________ 22 22 22 22 16 II 16 15 16 22 Wi I8*| 21 16 28 25*j , 16* I9*| 23 255 '1392 575 774 ,, 22 16 37 1015 _ , 20 18 51 30 26*| 1270 , 20 20 18 18 18 18 18 18 20 24 24 24 60 74 116 218 290 385 34*j 39 52*| 60 69 28 35, 40 46 54 1540 2180 3280 4440 5700 6950 , i _ 16 28 472 89 99, 71 80 i 84601 i 9260i 16 28 865 I09*| 88 ' 11250 i 16 32 1002 118* 94 13400 *Temp. diff. 20 deg. F. Stack ht. 40 ft. Wind velocity 10 m.p.h. From teats of actual operating con ditions by Prof. G. L. Tuve, Case School of Applied Science, Cleveland. Ohio. ; Other Burt Ventilators * Sliding Sleeve Damper Unit--Metal or Glass Top--a moderate priced gravity unit of exceptional quality. - Ball Bearing Revolving Ventilator-- Accurately balanced, well braced, double bearing unit of high capacity. Monovent Continuous Ridge Venti lator--designed to "take the roof off." Ten foot sections fit together perfectly to give as long an outlet as desired. Vertical operating damper with fully protected lifting mechanism. Burt Round Louvre Dampers Gan be fitted into any Burt Ventilator or damper motor control. Latter available where an extremely close fitting damper is for manual or thermostatic operation to needed. Edges felted if required. Well suit requirements of particular job. balanced and easy operating in either hand Write for Burt Handbook of Ventilation Data 1059 Water Conditioning Ferro-Nil Corporation 500 Fifth Avenue New York City WATER CONDITIONING FOR AIR CONDITIONING New Department of Justice Building, Washington, D. C. All water used for washing air picks up corrosive matter from the air. The corrosive matter may be oxygen, carbon dioxide, sulphur tri-oxide or sulphur di-oxide. In air conditioning systems where water is recirculated, the amount of acidic material contained in the water may reach very high levels. This acid water will corrode metallic surfaces with which it comes in contact. In severe cases equipment has been known to fail after three months operation due to corrosive action of water used. . Ferro-Nil Service by maintaining water ip a non-corrosive condition, prevents corrosion. Corrosion1 causes high rates of depreciation. Ferro-Nil Service by maintaining metallic surfaces free from rust and scale affords optimum heat transfer efficiencies at all times. We number among our clients, nationally known corporations such as:-- Rockefeller Center . National Broadcasting Company , Columbia Broadcasting Company Runkel Chocolate Company Metropolitan Life Insurance Company U. S. Government SUBSTANTIAL DOLLAR SAVINGS GUARANTEED Let us submit estimate of cost of Ferro-Nil Service for your air conditioning equipment. The illustration depicts one of the many fine buildings where Ferro-Nil Service is used. 'See discussion of Corrosion Chapter 34.' . 1060 INDEX TO MODERN EQUIPMENT American Society of Heating and Ventilating Engineers Guide, 1936 AIR CLEANING EQUIPMENT Modine Manufacturing Co., 912 Betz Unit Air Cooler Co., 804 Aeriet Air Conditioner Company. Niagara Blower Company, 814-815 E. K. Campbell Heating Co., 909 799 Norge Division, Borg-Wamer Cor Carrier Engineering Corporation, Airtemp Incorporated, 800 poration, 830, 847, 892 American Air Filter Company, Inc., Parks-Cramer Company, 813 825 Coppus Engineering Corporation, 850-851 Savage Arms Corporation, 816 852 American Blower Corporation, 802 Servel, Inc.. 817 803 B. F. Sturtevant Co., 908 Delco Appliance Corporation. 835, 876, 890 American Foundry Equipment Co., Thermal Units Manufacturing The, 910 Company, 818 Niagara Blower Company, 814-815 Owens-Illinois Glass Company, 854 American Radiator Company, 801, 861-865 Buffalo Forge Company, 901 Canadian Sirocco Co., Ltd., 802 803 Trane Company, The, 1027 Vilter Manufacturing Company, The, 832 Westinghouse Electric & Manu facturing Co., 819, 970 Savage Arms Corporation, 816 L. J. Wing Mfg. Co., 906-907 AIR RECEIVERS (See Receivers, Air) Clarage Fan Company, 805 Coppus Engineering Corporation, 852 Delco Appliance Corporation, 835, 876,890 - Williams Oil-O-Matic Heating Cor poration, 848, 893 York Ice Machinery- Corporation, 820 Young Radiator Company, 914 AIR VALVES (See Valves, Air) AIR VELOCITY METERS (See Meiers. Air Velocity) ' Gar Wood Industries, Inc., 836-837 Independent Air Filter Co., 853 AIR ELIMINATORS AIR VELOCITY REGULATORS Kelvinator Corporation, 808-811 L. J. Mueller Furnace Co., 844-845 Owens-Illinois Glass Company, 854 Parks-Cramer Company, 813 Research Corporation, 821 C. A. Dunham Co.. 1012-1013 Mueller Steam Specialty Co., Inc., 1023 New York Air Valve Corporation, 1058 Powers Regulator Co., The, 1050 1051 Young Ventilating Company, The, 849 Savage Arms Corporation, 816 Somers Air Filter Sales Co., 855 Staynew Filter Corporation, 856 . B, F. Sturtevant Co., 908 Unit Heater and Cooler Co., The, 913 Wilson & Company, 962 AIR COMPRESSORS (.See Com pressors, Air) Sarco Company, Inc., 1024-1025 Sterling Engineering Company, 1026 Warren Webster & Company, 1028-1030 Wright-Austin Co., 1031 AIR FILTERS (See Air Cleaning Equipment) AIR HEATING SYSTEMS (See AIR WASHERS Aeriet Air Conditioner Company, 799 American Blower Corporation, 802 803 American Foundry Equipment Co., The, 910 American Radiator Company, 801, 861-865 Bayley Blower Company, 900 AIR COOLING AND DEHUMIDIFYING APPARATUS Heating Systems, Air) AIR MEASURING AND RE Betz Unit Air Cooler Co., 804 Buffalo Forge Company, 901 E. K. Campbell Heating Co., 909 Aeriet Air Conditioner Company, CORDING INSTRUMENTS Canadian Sirocco Co., Ltd., 802 . . 799 . American Blower Corporation, 802 803 . .. Aerofin Corporation, 915-917 803 Carrier Engineering Corporation, Airtemp Incorporated, 800 Babcock & Wilcox Company, The, 825 . , American Blower Corporation, 802 877 Clarage Fan Company, 805 803 - Bristol Company, The, 929 Gilbert & Barker Mfg. Co., 840-842 American Moistening Company, Brown Instrument Company, 930 Henry Furnace & Foundry Co., 822 . . Builders Iron Foundry, 965 843, 896 American Radiator-Company, 801, Canadian Sirocco Co., Ltd., 802-803 Meyer Furnace Company, The, 846 861-865 Carrier Engineering Corporation, L. J. Mueller Furnace Co., 844-845 Baker Ice Machine Co., Inc., 823 . 825 . Niagara Blower Company, 814-815 Bayley Blower Company, 900 Betz Unit Air Cooler Co., 804 Buffalo Forge Company, 901 E. K. Campbell Heating Co., 909 Canadian Sirocco Co., Ltd., 802-803 Carbondale Machine Corporation, 824 Chicago Pump Company, 992-993 Consolidated Ashcroft Hancock Parks-Cramer Company, 813 Co., Inc., 931 Savage Arms Corporation, 815 Julien P. Friez & Sons, Inc., 1037 B. F. Sturtevant Co., 908 Grinnell Company, Inc., 9194)21, Trane Company, The, 1027 1015 Unit Heater and Cooler Co., The, Hays Corporation, 932 913 Illinois Testing Laboratories, Inc., 'Vilter Manufacturing Company, 933 ' The, 832 ' Clarage Fan Company, 805 Electrol Incorporated, 891 Johnson Service Company, 1040 York Ice Machinery Corporation, 1041 820 Feeders Manufacturing Co., 911 Minneapolis-Honeywell Regulator Frick Company (Incorporated),827 Company, 1044-1049 AMMONIA COILS (See Coils, Frigidaire Corporation, 806-807 Parks-Cramer Company, 813 Ammonia) General Electric Company, 838^ Taylor Instrument Companies, 936 839,968-969 . 937 ANEMOMETERS Grinnell Company, Inc., 919-921, Julien P. Friez & Sons, Inc., 1037 1015 AIR MOISTENING APPAR Taylor Instrument Companies, 936 Henry Furnace & .Foundry Co., ATUS (See Humidifiers) 937 843. 896 Ilg Electric Ventilating Company, 903 . AIR PURIFYING APPARATUS Aeriet Air Conditioner Company, ASBESTOS PRODUCTS (See In sulation) Ingersoll-Rand Company, 828-829 799 Kelvinator Corporation, 808-811 McQuay, Incorporated; 812 . American Air Filter Company, Inc., AUTOMATIC COAL BURNERS 850-851 ' (See Coal Burners, Automatic), Numerals following Manufacturers' Names refer to pages In the Catalog Data Section American Society of Heating and Ventilating Engineers Guide, 1936 AUTOMATIC HEATING SYS TEMS (See Healing Systems, Automatic) AUTOMATIC SHUTTERS (See Shutters, Automatic) AUTOMOBILE HEATER FANS E. K, Campbell Heating Co., 909 Delco Appliance Corporation, 835, 876, 890 Torrington Mfg. Co., The, 904-905 Ilg Electric Ventilating Company, 903 Meyer Furnace Company, The, 846 L. J. Mueller Furnace Co., 844-845 John J. Nesbitt, Inc., 922-923 B. F. Sturtevant'Co.; 908 Trane Company, The, 1027 Williams Oil-O-Matic Heating Cor poration, 848, 893 L. J. Wing Mfg; Co., 906-907 BLOWERS, Pressure E. K. Campbell Heating Co., 909 Crane Co., 868-869 . Delco Appliance Corporation, 835, 876.890 * L. J. Mueller Furnace Co., 844-845 National Radiator Corporation, 870-871 United States Radiator Corpora tion, 874 Utica Radiator Corporation, 1000 Weil-McLain Company, 875 BENDS, Pipe Baker Ice Machine Co., Inc., 823 Carbondale Machine Corporation, . 824 Crane Co., 868-869 . Frick Company (Incorporated), 827 Grinnell Co., Inc., 919-921, 1015 Vilter Manufacturing Co., The, 832 York Ice Machinery Corporation, 820 BENDS, Return (See Pipe, Return Bends). .. American Blower Corporation, 802 803 Bayley Blower Company, 900 Buffalo Forge Company, 901 Canadian Sirocco Co., Ltd., 802-803 Champion Blower & Forge Co., 902 Clarage Fan Company, 805 Henry Furnace & Foundry Co., 843, 896 Ingersoll-Rand Company, 828-829 B. F. Sturtevant Co., 908 L. J. Wing Mfg. Co.. 906-907 BLOWERS, Turbine BOILERS. Down Draft American Radiator Company, 801, 861-865 Farrar & Trefts, Incorporated, 882 Fitzgibbons Boiler Company, Inc.,. 880-881 Henry Furnace & Foundry Co., 843. 896 E. Keeler Company, 883 Kewanee Boiler Corporation, 884 885 ' Lookout Boiler & Mfg. Company, 886-887 BLAST HEATERS (See Healers, Blast) .- BLOCKS, Asbestos . Clarage Fan Company, 805 Coppus Engineering Corporation, 852 General Electric Company, 838 BOILERS, Electric Crane Co., 868-869 General Electric Company, 838 Eagle-Picher Lead-Company, The, 839, 968-969 839, 968-969 941 B. F. Sturtevant Co., 908 Ehret Magnesia Manufacturing L. J. Wing Mfg. Co., 906-907 BOILERS, Gas Burning Co., 946 Johns-Manville. 950-951 Ruberoid Co., The, 956-957 BLOWER WHEELS (See Wheels, Blower) BLOWERS, Fan (See Fens, Supply and Exhaust) ' BLOWERS, Forced Draft American Blower Corporation, 802 803 - Bayley Blower Company, 900 Buffalo, Forge Company, 901 Canadian Sirocco Co., Ltd., 802, 803 Clarage Fan Company, 805 Champion Blower & Forge Co., 902 Coppus Engineering Corporation, 852 BLOWERS, Warm Air Furnace Air Controls, Inc., 834 . American Blower Corporation, 802 803 . Buffalo Forge Company, 901 E. K. Campbell Heating Co., 909 Canadian Sirocco Co., Ltd., 802-803 Champion Blower & Forge Co., 902 Clarage Fan Company, 805 ' Henry Furnace & Foundry Co., 843, 896 Meyer Furnace Company, The, 846 L. J. Mueller Furnace Co., 844-845 Trane Company, The, 1027 BOILER-BURNER : Airtemp Incorporated, 800 Burnham Boiler Corporation, 866 867 \ - Delco Appliance Corporation, 835, American Radiator Company, 801. 861-865 Burnham Boiler Corporation, 866, 867 E. K. Campbell Heating Co., 909 Farrar & Trefts, Incorporated,' 882 Fitzgibbons Boiler Company, Inc., 880-881 General Electric Company, 838 839, 968-969 E. Keeler Company, 883 Kewanee Boiler Corporation, 884 885 Lookout Boiler & Mfg. Company, 886-887 L. J. Mueller Furnace Co., 844-845 National Radiator Corporation, 870-871 Waterfilm Boilers, Incorporated, 888 Curtis Refrigerating Machine Com pany, Division of Curti3 Manu 876,890 . . Gar Wood Industries, Inc., 836-837 BOILERS, Heating facturing Company, 826 General Electric Company, 838 American Radiator Company, 801, Delco Appliance Corporation. 835, 839, 968-969 861-865 876, 890 Hays Corporation, 932 Gilbert & Barker Mfg. Co., 840-842 Bigelow Company. The, 878 Henry Furnace & Foundry Co., Burnham Boiler Corporation, 866 Henry Furnace & Foundry Co., 843, 896 867 843.896 Servel, Inc., 817 . Kelvinator Corporation, 808-811 E. K. Campbell Heating Co., 909 . Williams Oil-O-Matic Heating Cor Crane Co., 868*869 B. F. Sturtevant Co., 908 poration, 848, 893 Delco Appliance Corporation,' 835, Utica Radiator Corporation,. 1000 L. J. Wing Mfg. Co., 906-907 BOILER COMPOUNDS (SciCom- 876, 890 Electrol Incorporated, 891 pounds. Boiler) . Farrar & Trefts, Incorporated, 882 BLOWERS, Heating and Venti lating , Air Controls, Inc., 834 BOILER COVERING (See Cover- ing. Pipes and Surfaces) . . Fitzgibbons Boiler Company, Inc., 880-881 . Henry Furnace & Foundry Co., American Blower Corporation, 802 BOILER FEED PUMPS ' (See 843, 896 803 . American Machine and Metals Manufacturing Corp., DeBothezat Division, 899 Pumps, Boiler Feed) -. BOILER FEEDERS (See Feeders, Boiler) E. Keeler Company, 883 Kewanee Boiler Corporation, 884 885 Lookout Boiler & Mfg. Company, Bayley Blower Company, 900 BOILER Buckeye Blower Company, 922-923 Boiler) Buffalo Forge Co., 901 TUBES (See Tubes, 886-887 L. J. Mueller Furnace Co., 844-845 National Radiator Corporation, E. K. Campbell Heating Co., 909 BOILER WATER TREATMENT 870-871 . Canadian Sirocco Co., Ltd., 802-803 Vinco Company, Inc., The, 857 Spencer Heater Company, 872-873. Champion Blower & Forge Co,, 902 United States Radiator Corpora Clarage Fan Company. 805 * _ BOILERS, Cast-Iron tion, 874 `' Coppus Engineering Corporation, American Radiator Company, 801, Utica'Radiator Corporation, 1000 852 . Henry Furnace & Foundry Co.; 861-865 Burnham Boiler Corporation, 866 Wt aggtegrfilm, Boilers, Incorporat ed, 843. 896 867 Weil-McLain Company, 875 . Please mentio:n THE GUIDE 1936 when writing to Advertisers 1062 Index to Modern Equipment BOILERS, Magazine Feed BREECHINGS AND Iron Fireman Manufacturing Com American Radiator Company, 801, CHIMNEYS 861-865 Bigelow Company, The, 878 - pany, 894-895 Whiting Corporation, 1033 Spencer Heater Company, 872-873 Weil-McLain Company, 875 BOILERS, Oil Burning American Radiator Company, 801 861-865 Bigelow Company, The, 878 Burnham Boiler Corporation, 866 867 E. K. Campbell Heating Co., 909 Crane Co.. 868-869 Davis Engineering Corporation, 928 Delco Appliance Corporation, 835, Farrar & Trefts, Incorporated, 882 E. Keeler Company, 883 Young Ventilating Company, The, BURNERS, Automatic Electrol Incorporated, 891 General Electric Company, 838 839, 968-969 Gilbert & Barker Mfg. Co., 840-842 Iron Fireman Manufacturing Com pany. 894-895 - Kelvinator Corporation, 808-811 COILS, Aluminum Aerofin Corporation, 916917 Frigidaire Corporation, 806807 McQuay, Incorporated, 812 Niagara Blower, Company, 814-815 Thermal Units Manufacturing Company, 818 Trane Company, The, 1027 Unit Heater and Cooler Co., The, 913 Wolverine Tube Company, 980 Young Radiator Company, 914 876, 890 Electrol Incorporated, 891 Farrar & Trefts, Incorporated, 882 Fitzgibbons Boiler Company, Inc., 880-881 Gar Wood Industries, Inc., 836-837 Norge Division, Borg-Warner Cor poration, 830, 847, 892 Whiting Corporation, 1033 Williams Oil-O-Matic Heating Cor poration, 848. 893 COILS, Ammonia . Baker Ice Machine Co., Inc., 823 Carbondale Machine Corporation. 824 Carrier Engineering Corporation, General Electric Company, 838 BURNERS, Coal (See Coal 839, 968-969 Burners) E. Keeler Company, 883 825 Clarage Fan Company, 805 Crane Co., 868-869 Kewanee Boiler Corporation, 884 885 BURNERS, Gas (See Gas Burners) Frick Company (Incorporated), 827 G & O Manufacturing Company, Lookout Boiler & Mfg. Company, 886-887 . BURNERS, Oil (See Oil Burners) The. 918 McQuay, Incorporated, 812 L. J. Mueller Furnace Co., 844-845 National Radiator Corporation, 870-871 Norge Division, Borg-Wamer Cor poration, 830, 847, 892 Spencer Heater Company, 872-873 United States Radiator Corpora tion, 874 Utica Radiator Corporation, 1000 Waterfilm Boilers, Incorporated, CEMENT,' Asbestos Eagle-Picher Lead Company, The, 941 . Ehret Magnesia Manufacturing Co., 946 Johns-Manville, 950-951 Owens-Illinois Glass Company, 854 Ruberoid Co., The, 956-957 Niagara Blower Company, 814-815 Thermal Units Manufacturing Company, 818 . Trane Company, The, 1027 Unit Heater and Cooler Co., The, 913 . Vilter Manufacturing Company, The, 832 Wittenmeier Machinery Company, 833 888 ' Weil-McLain Company. 875 CEMENT^ Rock Wool Agasote Millboard Co., The, 939 York Ice Machinery Corporation, 820 Young Radiator Company, 914 BOILERS, Steel American Radiator Company, 801, 861-865 * Bigelow Company, The, 878 Burnham Boiler Corporation, 866 867 Ehret Magnesia Manufacturing Co., 946 .' Johns-Manville, 950-951 ' Ruberoid Co., The, 956-957 Standard Lime & Stone Co., The, 958 - COILS, Brass E. B. Badger & Sons Co.. 898 Carrier Engineering Corporation, 825 Chase Brass & Copper Co., Incor Combustion Engineering Company, Inc., 879. Davis Engineering Corporation, CHAIN PULLEYS Chain) (See Pulleys, ` porated, 974-975, 999 Crane Co., 868-869 . Grinnell Company, Inc.. 919-921, 928 1015 ' Electrol Incorporated, 891 CIRCULATORS, Hot Water Farrar & Trefts, Incorporated, 882 Heating Wolverine Tube Company, 980 Fitzgibbons Boiler Company,.Inc., . 880-881 Frick Companii(Incorporated), 827 E. Keeler Company, 883 Kewanee Boiler Corporation, 884 885 _ ^ Lookout Boiler &* Mfg. Company, 886-887 National Radiator Corporation, 870-871 Spenceri Heater Company, 872-873 United States Radiator Corpora tion, 874 " ,, Waterfilm Boilers, Incorporated, 888 American Radiator Company, 801. 861-865 ; . .. Bell and Gossett Company, 924-925 General Electric Company: 838 839; 968-969 Sterling Engineering Company, 1026 H. A. Thrush & Co., 926927 Westco Pump Corporation, 998 Westinghouse Electric & Manu facturing Co.. 819, 970 CLEANERS, Air (See Air Cleaning Equipment) ' COILS, Pipe, Copper . American Brass Company, The. 972-973 E. B. Badger & Sons Co., 898 Baker Ice Machine Co., Inc., 823 Bell and Gossett Company, 924-925 Carrier Engineering Corporation, 825 Chase Brass & Copper Co., Incor porated, 974-975, 999 ' Crane Co.. 868-869 Curtis Refrigerating Machine Com pany, Division of Curtis Manu facturing Company, 826 Frick Company .(Incorporated), 827 BOILERS. Water Tube American Radiator Company, 801, 861-865 Babcock & Wilcox Company, The, 877 Bigelow Company, The,'878 Burnham Boiler Corporation, 866 867 COAL BURNERS Babcock & Wilcox Company, The, 877 Buffalo Forge Company, 901 Detroit Stoker Company, 1032 Iron Fireman Manufacturing Com pany, 894-895 ' Whiting Corporation, 1033 ` Kelvinator Corporation, 808-811 Kewanee Boiler Corporation, 884 885 McQuay, Incorporated, 812 Mueller Brass Co.. 976977 Norge Division, Borg-Wamer Cor poration, 830, 847, 892 Revere Copper and Brass Incor porated, 979 .` Combustion Engineering Company, Inc.-, 879 COAL BURNERS, Automatic Servel', Inc., 817 ' Streamline Pipe and Fittings Co., , Fitzgibbons Boiler Company, Inc., Combustion Engineering Company, 976977 850-881 Inc., 879 Wolverine Tube Company, 980 E. Keeler Company, 883 Detroit Stoker Company, 1032 York Ice Machinery Corporation, National Radiator Corporation, Henry Furnace & Foundry Co;, 820 870-871 843, 896 Young Radiator Company, 914 Numerals following Manufacturers* Names refer to pages'in the Catalog Data Section American Society of Heating and Ventilating Engineers Guide, 1936 COILS, Pipe, Iron . Universal Cooler Corporation, 831 CONTROL EQUIPMENT, E. B. Badger & Sons Co., 898 Bayley Blower Company, 900 . Carbondale Machine Corporation, 824 Clarage Fan Company, 805 Crane Co., 868-869 . Frick Company (Incorporated), 827 Grinnell Company, Inc., 919-921, 1015 Vilter Manufacturing Company, Vilter Manufacturing Company, The, 832 Westinghouse Electric & Manu facturing Co., 819, 970 Williams Oil-O-Matic Heating Cor poration, 848, 893 Wittenmeier Machinery Company, 833 York Ice Machinery Corporation, 820 Combustion Bristol Company, The, 929 Brown Instrument Company, 930 Detroit Lubricator Company, 1036 General Controls, 1042 Hays Corporation, 932 Henry Furnace &. Foundry Co., 843, 896 Leeds & Northrup Company, 934 Mercoid Corporation, The, 1043 The, 832 York Ice Machinery Corporation, 820 CONCRETE INSERTS (See In serts, Concrete) Minneapolis-Honeywell Regulator Company, 1044-1049 National Regulator Co., 1052 COILS, Tank E. B. Badger & Sons Co., 898 Baker Ice Machine Co., Inc., 823 Bell and Gossett Company, 924-925 Clarage Fan Company, 805 ' Crane Co., 868-869 Frick Company (Incorporated), 82' McQuay. Incorporated, 812 Vilter Manufacturing. Company The, 832 York Ice Machinery Corporation 820 CONDENSERS Aerofin Corporation, 915-917 Baker Ice Machine Co., Inc., 823 Carbondale Machine Corporation, 824 Carrier Engineering Corporation, 825 Curtis Refrigerating Machine Com pany. Division of Curtis Manu facturing Company, 826 Frick Company (Incorporated), 827 G & O Manufacturing Company, The, 918 COMPOUNDS, Asphalt, for Conduits Ric-wiL Company, The, 963 Ingersoll-Rand Company, 828-829 Modine Manufacturing Co., 912 Thermal Units Manufacturing Company, 818 . COMPOUNDS, Boiler Trane Company, The, 1027 Vilter Manufacturing Company, Vine Company, Inc., The, 857 The, 832 Westinghouse Electric & Manu COMPOUNDS, Boiler and Radi facturing Co., 819, 970 ator Sealing Wittenmeier Machinery Company, Dole Valve Company, The, 1053 Vmco Company, Inc., The, 857 833 . York Ice Machinery Corporation, 820 COMPOUNDS. Cleaning Young Radiator Company, 914 Westinghouse Electric & Manu facturing Co., 819, 970 CONTROLLERS AND CON TROL EQUIPMENT (See also Humidity and Temperature Con trol) American Radiator Company, 801, 861-865 Barber-Colman Company, 1034 1035 Bristol Company, The, 929 Builders Iron Foundry, 965 Carrier Engineering Corporation, 825 Consolidated Ashcroft Hancock Co., Inc., 931 Detroit Lubricator Company, 1036 Foster Engineering Co., 1056 Julien P. Friez & Sons, Inc., 1037 Fulton Sylphon Co., 1038-1039 General Controls, 1042 Hays Corporation, 932 Hoffman Specialty Co., Inc., 1016 1017 - Henry Furnace & Foundry Co., 843, 896 Leeds & Northrup Company, 934 Aquatic Chemical & Metallurgical Engineers, 860 COMPRESSORS, Air American Steam Pump Company, 991 Baker Ice Machine Co., Inc., 823 Carbondale Machine Corporation, 824 Curtis Refrigerating Machine Com pany, Division of Curtis Manu facturing Company, 826 CONDUITS, Underground Fit tings American District Steam Company; 897 ' . Chase Brass & Copper Co., Incor porated, 974-975, 999 General Electric Company, 838 839, 968-969 . Ric-wiL Company, The, 963 Underground Steam Construction Co., 964 Minneapolis-Honeywell Regulator Company, 1044-1049 Powers Regulator Co., The, 1050 1051 Sarco Company, Inc., 1024-1025 Sterling Engineering Company, 1026 Taylor Instrument Companies, 936 937 Warren Webster & Company, 1028 1030 Westinghouse Electric & Manu General Electric Company, 838 facturing Co., 819, 970 839, 968-969 CONDUITS, Underground Pipe Gilbert & Barker Mfg. Co., 840-842 American District Steam Company, CONVECTION HEATERS Ingersoll-Rand Company, 828-829 Nash Engineering Company, 994 995 B. F. Sturtevant Co., 908 897 E. B. Badger & Sons Co., 898 Chase Brass & Copper Co., Incor porated, 974-975, 999. American Radiator Company, 801, 861-865 Chase Brass & Copper Co., Incor porated, 974-975, 999 Ehret Magnesia Manufacturing C. A. Dunham Company, 1012 COMPRESSORS. Refrigeration Co., 946 1013 Aeriet Air Conditioner Company, 799 Airtemp Incorporated, 800 Baker Ice Machine Co., Inc., 823 Carbondale Machine Corporation, 824 Carrier Engineering Corporation, 825 Curtis Refrigerating Machine Com Frick Company (Incorporated), 827 Johns-Manville, 950-951 Jones & Laughlin Steel Corpora tion, 971 . Republic Steel Corporation, 978 Ric-wiL Company, The, 963 Underground Steam Construction - Co., 964 Zonolite Corporation, 960-961 McQuay, Incorporated, 812 Modine Manufacturing Co., 912 National' Radiator Corporation, 870-871 John J. Nesbitt, Inc., 922-923 Revere Copper and Brass Incor porated, 979 Trane Company, The, 1027 Tuttle & Bailey, Inc., 1004-1005 . pany, Division of Curtis Manu facturing Company, 826 Frick Company (Incorporated), 827 CONTROL, Damper Air Volume United States Radiator Corpora tion, 874 Utica Radiator Corporation, 1000 Frigidaire Corporation, 806-807 Auer Register Co., The, 1001 Warren Webster & Company, 1028 General Electric Company, 838 Hart & Cooley Manufacturing Co., 1030 839, 968-969 1002-1003 Young Radiator Co., 914 Ingersoll-Rand Company, 8,28-829 KelvinaCor Corporation, 808-811 Independent Register & Mfg. Co., 1006 COOLING EQUIPMENT, Air Norge Division, Borg-Warner Cor Tuttle & Bailey, Inc., 1004-1005'. Aeriet Air Conditioner. Company, poration, 830, 847, 892 Waterloo Register Company, The, 799 ' B. F. Sturtevant Co., 908 1007 -. Aerofin Corporation, 915-917 Thermal Units Manufacturing . Young Ventilating!1Company. The. Air Controls, Inc.,.834 . Company, 818 849 Airtemp Incorporated, 800 Please menticn THE GUIDE 1936 when writing to Advertisers ' 1064 Index to Modern Equipment American Blower Corporation, 802 Vilter Manufacturing Company, ' National Regulator Co., 1052 803 The, 832 Powers Regulator Co., The, 1050 Baker Ice Machine Co., Inc., 823 Wittenmeier Machinery Company, 1051 Betz Unit Air Cooler Co., 804 833 Sarco Company, Inc., 1024-1025 Buckeye Blower Company, 922-923 York Ice Machinery Corporation, H. A. Thrush & Co., 926-927 Buffalo Forge Company, 901 820 Warren Webster & Co., 1028-1030 E. K. Campbell Heating Co., 909 Young Radiator Company, 914 Westinghouse Electric & Manii- Canadian Sirocco Co., Ltd., 802-803 Carbondale Machine Corporation, 824 Carrier Engineering Corporation,. 825 CORROSION, Treatment of Aquatic Chemical & Metallurgical Engineers, 860 Ferro-Nil Corporation, 1060 facturing Co., 819-970 DAMPER REGULATORS, Furnace Barber-Colman Company, 1034 Clarage Fan Company, 805 Fedders Manufacturing Co., 911 Frick Company (Incorporated), 827 Frigidaire Corporation, 806-807 General Electric Company, 838 839, 968-969 .* Henry Furnace & Foundry Co., 843, 896 Ilg Electric Ventilating Company, 903 Ingersoll-Rand Company, 828-829 Kelvinator Corporation, 808-811 COVERING, Ammonia Pipe 1035 Armstrong Cork Products Co., 940 Baker Ice Machine Co., Inc., 823 Eagle-Picher Lead Company, The, 941 Ehret Magnesia Manufacturing Co. 946 . Johns-Manville, 950-951 Mundet Cork Corp., 952 Ruberoid Co., The, 956-957 Zonolite Corporation, 960-961 Detroit Lubricator Company, 1036 Foster Engineering Co., 1056 Fulton Sylphon Co., 1038-1039 General Controls, 1042 , Hart & Cooley Manufacturing Co.. 1002-1003 Henry Furnace & Foundry Co., 843,896 . Leeds & Northrup Co., 934 ' .Minneapolis-Honeywell Regulator Company, 1044-1049 - McQuay, Incorporated, 812 Modine Manufacturing Co., 912 John J". Nesbitt, Inc., 922-923 Niagara Blower Company, 814-815 Norge Division, Borg-Warner Cor poration, 830, 847, 892 Savage Arms Corporation, 816 Servel, Inc., 817 , Thermal Units Manufacturing ' Company, 818 . Trane Company, The, 1027 Unit Heater and Cooler Co., The, 913 Vilter Manufacturing Company, The, 832 Westinghouse Electric & Manu facturing Co., 819, 970 Wittenmeier Machinery Company, 833 York Ice Machinery Corporation, COVERING, Pipe AUol Insulation Co., 942-943 Armstrong Cork Products Com pany, 940. Baker Ice Machine Co., Inc., 823 Eagle-Picher Lead Company, The, 941 Ehret Magnesia Manufacturing Co.. 946 Frick Company (Incorporated), 827 Johns-Manville, 950-951 Mundet Cork Corp., 952 Owens-Illinois Glass Company, 854 Ric-wiL Company, The, 963 Ruberoid Co.. The, 956-957 S taQn5gdard Lime & Stone Co., The, Wilson & Co., 962 Zonolite Corporation, 960-961 National Regulator Co., 1052 Powers Regulator Co., The. 1050 1051 Sarco Company, Inc., 1024-1025 Tuttle & Bailey, Inc., 1004-1005 DAMPERS, Air Volume Con trol Air Controls, Inc., 834 Auer Register Co., The, 1001 Hart & Cooley Manufacturing Co.. 1002-1003 Independent Register & Mfg. Co., 1006 Tuttle & Bailey, Inc., 1004-1005 Waterloo Register Company. The. 1007 Young Ventilating Co., The, 849 DAMPERS, Flue 820 Young Radiator Company, 914 COOLING EQUIPMENT, Oil Aerofin Corporation, 915-917 Carbondale Machine Corporation, 824 Frick Company (Incorporated), 827 G & O "Manufacturing Company, The, 918 Niagara Blower Company, 814-815 Unit Heater and Cooler Co., The, 913 Williams Oil-O-Matic Heating Cor poration, 848, 893 York Ice Machinery Corporation, 820 Young Radiator Company, 914 COVERING, Surfaces Alfol Insulation Co., 942-943 Armstrong Cork Products Com pany, 940 - Baker Ice Machine Co., Inc., 823 Ehret Magnesia Manufacturing Co. 946 Johns-Manville, 950-951 Mundet Cork Corp., 952 Owens-Illinois Glass Company, 854 Ruberoid Co., The, 956-957 Wilson &.Co., 962 Zonolite Corporation, 960-961 CUTTING AND WELDING AP PARATUS (See Welding and Cutting Apparatus) E. K. Campbell Heating Co., 909 Henry Furnace & Foundry Co.. 843, 896 Tuttle & Bailey, Inc., 1004-1005 Young Ventilating Company, The, DAMPERS, Mechanical Air Controls, Inc., 834 ' Buffalo Forge Company, 901 Carrier Engineering Corporation, Fulton Sylphon Co., 1038-1039 . Hart & Cooley Manufacturing.Co.. 1002-1003 Henry Furnace & Foundry Co., 843, 896 . Johnson Service Company, 1040 COOLING EQUIPMENT, Water Aeriet Air Conditioner Company, 799 Aerofin Corporation, 915-917 American Blower Corporation, 802 803 DAMPER REGULATORS, Boiler (See also Regulators) American Radiator Company, 801, 861-865 . Barber-Colman Company, 1034 1035 . 1041 National Regulator Co., 1052. Powers Regulator Co., The, ]L050- 1051 Young Ventilating Company, The, 849 . Baker Ice Machine Co., Inc., 823 Detroit Lubricator Company, 1036 DEAERATORS Buffalo Forge Company, 901 Canadian Sirocco Co., Ltd., 802-803 C. A. Dunham Company, 1013 1012 American Radiator Company. 801. 861-865 . Carbondale Machine Corporation, Foster Engineering Co., 1056 824 Fulton Sylphon Co., 1038-1039 DIFFUSERS (See Ventilators, Frick Company (Incorporated), 827 General Controls, 1042 Floor and Wall) ' Frigidaire {Corporation, 806-807 Hart & Cooley Manufacturing Co., McQuay, Incorporated, 812 1002-1003 DRAFT APPARATUS (See Niagara Blower Company, 814-815 Hays Corporation, 932 . Blowers, Forced Draft) . Norge Division, Borg-Warner Cor Henry Furnace & Foundry Co., poration, 830, 847, 892 843, 896 DRYING EQUIPMENT Research Corporation, 821 Hoffman Specialty Co., Inc., 1016 Aeriet - Air Conditioner* Company. Thermal Units Manufacturing 1017 799 . - Company, 818 ' Illinois Engineering Co.. 1018-1019 American Radiator Company. 801. Trane Company, The, 1027 Leeds & Northrup Company, 934 861-865 . Unit Heater and Cooler Co., The, Minneapolis-Honeywell Regulator Betz Unit Air Cooler Co., .804 913 Company, 1044-1049 Buffalo Forge Company, 901 Numerals following Manufacturers* Names refer to pages in the Catalog Data Section 1065 American Society of Heating and Ventilating Engineers Guide, 1936 Carrier Engineering Corporation, EXPOSITIONS Canadian Sirocco Co., Ltd., 802-803 825 Clarage Fan Company, 805 International Exposition Co., 889 Champion Blower & Forge Co., 902 Coppus Engineering Corporation, G & O Manufacturing Co., The, 918 McQuay, Incorporated, 812 B. F. Sturtevant Co.. 908 Thermal Units Manufacturing Company, 818 Trane Company, The, 1027 L. J. Wing Mfg. Co., 906-907 FAN BLADES American Blower Corporation, 802 803 Buffalo Forge Company, 901 Canadian Sirocco Co., Ltd., 802-803 Torrington Mfg. Co., The, 904-905 Westinghouse Electric & Manu 852 Delco Appliance Corporation, 835, 876, 890 General Electric Company, 838 839, 968-969 Henry Furnace & Foundry Co., ' 843. 896 Ilg Electric Ventilating Company, facturing Co., 819, 970 DUST COLLECTING EQUIP MENT FANS, Centrifugal 903 Westinghouse Electric & Manu facturing Co., 819, 970 American Air Filter Company, Inc., Air Controls, Inc., 834 L. J. Wing Mfg. Co.. 906-907 850-851 . American Blower Corporation, 802 American Blower Corporation, 802 803 803 ^ Bayley Blower Company, 900 FANS, Propeller American Foundry Equipment Co., Buckeye Blower Company, 922-923 Air Controls, Inc., 834 The. 910 Buffalo Forge Company, 901 American Blower Corporation, 802 Buffalo Forge Company, 901 E. K. Campbell Heating Co., 909 803 Canadian Sirocco Co., Ltd., 802-803 Canadian Sirocco Co., Ltd., 802-803 American Machine and Metals Clarage Fan Company, 805 Clarage Fan Company, 805 Manufacturing Corp., DeBothe- Owens-Illinois Glass Company, 854 Coppus Engineering Corporation, zat Division, 899 Research Corporation, 821 852 Buffalo Forge Company, 901 B. F. Sturtevant Co., 908 General Electric Company, 838 Canadian Sirocco Co., Ltd., 802-803 839, 968-969 . Clarage Fan Company, 805 DUST COLLECTORS, Type Cloth Henry Furnace & Foundry Co., 843. 896 Coppus Engineering Corporation, 852 Ilg Electric Ventilating Company, General Electric Company, 838 American Air Filter Company, Inc., 903 839, 968-969 850-851 American Blower Corporation, 802 Meyer Furnace Company, The, 846 John J. Nesbitt, Inc., 922-923 Henry Furnace & Foundry Co., 843. 896 803 ^ American Foundry Equipment Co., The, .910 . Canadian Sirocco Co., Ltd., 802^803 Coppus Engineering Corporation, Niagara Blower Company, 814-815 Ilg Electric Ventilating Company, B. F. Sturtevant Co., 908 ` 903 Torrington Mfg. Co., The, 904-905 B. F. Sturtevant Co., 908 Trane Company, The, 1027 Thermal Units Manufacturing Company, 818 852 DUST SEPARATORS (See Sepa~ raters. Dust) EVAPORATORS FANS, Electric Barber-Colman Company, 1034 1935 Buffalo Forge Company, 901 Century Electric Company, 967 Coppus Engineering Corporation, Torrington Mfg. Co., The, 904-905 Trane Company, The, 1027 Westinghouse Electric & Manu facturing Co., 819, 970 L. J. Wing Mfg. Co., 906-907 Aerofin Corporation, 915-917 852 FANS, Supply and Exhaust . Baker Ice Machine Co., Inc., 823 Carrier Engineering Corporation, 825 Curtis Refrigerating Machine Com pany, Division Curtis Manu facturing Company, 826 Fedders Manufacturing Co., 911 Frick Company (Incorporated), 827 Frigidaire Corporation, 806-807 General Electric Company, 838 839, 968-969 McQuay, Incorporated, 812 Thermal Units Manufacturing - Company, 818 Trane Company, The, 1027 . Vilter Manufacturing Company, The. 832 . . Westinghouse Electric & Manu facturing Co., 819, 970 . Wittenmeier Machinery Company, 833 York Ice - Machinery Corporation, 820 Young Radiator Company. 914 Delco Appliance Corporation, 835,. 876, 890 ' General Electric Company, 838 839, 968-969 Henry Furnace fit Foundry Co., 843. 896 Ilg Electric Ventilating Company, 903 Westinghouse Electric & Manu facturing Co., 819, 970 L. J. Wing Mfg. Co., 906-907 Air Controls, Inc., 834 American Blower Corporation, 802 803 American Machine and Metals Manufacturing Corp., DeBothezat Division, 899 Bayley Blower Company, 900 Buckeye Blower Company, 922-923 Buffalo Forge Company, 901 E. K. Campbell Heating Co., 909 Canadian Sirocco Co., Ltd., 802-803 FANS, Furnace Am* Controls, Inc., 834 American Blower Corporation, 802 803 Buffalo Forge Company, 901 E. K. Campbell Heating Co., 909 Canadian Sirocco Co., Ltd., 802-803 Champion Blower & Forge Co., 902 Clarage Fan Company, 805 Coppus Engineering Corporation, 852 Henry Furnace & Foundry Co., Champion Blower & Forge Co., 902 Clarage Fan Company, 805 Coppus Engineering Corporation, 852 Delco Appliance Corporation, 835, 876. 890 General Electric Company, 838 839, 968-969 Henry Furnace & Foundry Co., 843. 896 Ilg Electric Ventilating Company, 903 L. J. Mueller Furnace Co., 844-845 EXHAUST HEADS (See Heads, 843. 896 Ilg Electric Ventilating Company, John J. Nesbitt, Inc., 922-923 Niagara Blower Company, 814-815 Exhaust) EXPANSION JOINTS American District Steam Company, 897 E. B. Badger & Sons Co., 898 Carrier Engineering Corporation, 903 Meyer Furnace Company, The, 846 L. J. Mueller Furnace Co., 844-845 Trane Company, The, 1027 L. J. Wing Mfg. Co., 906-907 FANS, Portable B. F. Sturtevant Co., 908. Thermal Units Manufacturing Company, 818 Trane Company, The, 1027 Westinghouse Electric & Manu facturing Co., 819, 970 L. J. Wing Mfg. Co.. 906-907 825 Crane Co., 868-869 Fulton Sylphon Co., 1038-1039 American Blower Corporation, 802 803 ' Barber-Colman Company, 1034 Illinois Engineering Company, 1018-1019 . Underground Steam Construction 1035 . Bayley Blower Company, 900 Buffalo Forge Company, 901 Co.. 964 . E. K. Campbell Heating Co., 909 FEED WATER HEATERS '(See Heaters, Feed Water) FEED WATER REGULATORS (See Regulators, Feed Water) Please mention THE GUIDE 1936 when writing to Advertisers Index to Modern Equipment FEEDERS, Boiler FURNACE-BURNER J. E. Lonergan Co., 1022 Crane Co., 868-869 General Controls, 1042 Delco Appliance Corporation, 835, Mercoid Corporation, The, 1043 876. 890 United States Gauge Co., 938 Kieley & Mueller, Inc., 1021 McDonnell & Miller. 858-859 John H. McGowan Company, The, 997 . Mueller Steam Specialty Co., Inc., 1023 Warren Webster & Company (Safety), 1028-1030 Westinghouse Electric & Manu facturing Co., 819, 970 Wright-Austin Co., 1031 Gar Wood Industries, Inc., 836-837 Gilbert & Barker Mfg. Co., 840-842 Henry Furnace & Foundry Co.. 843, 896 Meyer Furnace Company, The, 846 L. J. Mueller Furnace Co., 844-845 Norge Division, Borg-Warner Cor poration, 830, 847, 892 FURNACE HEATING SYS TEMS (See Healing Systems, Vilter Manufacturing Company, The, 832 GAGES, Compound .. Hoffman Specialty Co., Inc., 1016 1017 Sarco Company, Inc., 1024-1025 United States Gauge Co., 938 Warren Webster & Company, 1028 1030 Furnace) GAGES, HOT Water FEEDERS, Water Decatur Pump Company, 996 General Controls. 1042 Kieley & Mueller, Inc.. 1021 FURNACE REGULATORS (See Bell and Gossett Company, 924-925 Regulators, Furnace) Bristol Company, The, 929 Consolidated Ashcroft Hancock FURNACES, Electric Co., Inc., 931 McDonnell & Miller, 858-859 General Electric Company, 838 Julien P. Friez & Sons, Inc., 1037 Mueller Steam Specialty Co.. Inc.. 839; 968-969 Mercoid Corporation, The, 1043 1023 Westinghouse Electric & Manu M inneapolis- Honeywell Regulator Wright-Austin Co., 1031 facturing Co., 819, 970 Company, 1044-1049 FILTERS, Air (See Air Cleaning FURNACES, Warm Air New York Air Valve Corporation, 1058 Equipment) American Radiator Company, 801, H. A. Thrush & Co., 926-927 861-865 United States Gauge Co., 938 FITTINGS, Pipe, Flanged American Brass Co., The, 972-973 E. K. Campbell Heating Co.. 909 Carrier Engineering Corporation, GAGES, Pressure American Radiator Company, 801, 861-865 825 Delco Appliance Corporation, 835, American Radiator Company. 801. 861-865 Chase Brass & Copper Co., Incor 876, 890 Baker Ice Machine Co., Inc., 823 porated, 974-975, 999 Crane Co.. 868-869 Electrol Incorporated, 891 Bristol Company, The, 929 General Electric Company. -838 Brown Instrument Company, 930 Frick Company (Incorporated), 827 Grinnell Company, Inc., 919-921. 1015 - 839, 968-969 Gilbert & Barker Mfg. Co., 840-842 Henry Furnace & Fountry Co.. Consolidated Ashcroft Co., Inc., 931 Hays Corporation, 932 Hancock . Vilter Manufacturing Company. 843, 896 J. E. Lonergan Co., 1022 . The. 832 Lookout Boiler & Mfg. Company. Mercoid Corporation, The, 1043 York Ice Machinery Corporation. 886-887 Minneapolis-Honeywell Regulator 820 Meyer Furnace Company, The, 846 Co.. 1044-1049 L. J. Mueller Furnace Co., 844-845 New York Air Valve Corporation. FITTINGS, Pipe, Screwed Norge Division, Borg-Warner Cor 1058 Chase Brass & Copper Co., Incor porated, 974-975, 999 Crane Co., 868-869 Frick Company (Incorporated), 827 Grinnell Company, Inc., 919-921, 1015 Vilter Manufacturing Company. The. 832 . York Ice Machinery Corporation, poration, 830, 847, 892 Trane Company, The, 1027 GAGE BOARDS Bristol Company, The, 929 Consolidated Ashcroft Hancock Co., Inc., 931 Julien P. Friez & Sons, Inc., 1037 Hays Corporation, 932 J. E. Lonergan Co., 1022 Taylor Instrument Companies, 936 937 H. A. Thrush & Co., 926-927 United States Gauge Co., 938 GAGES, Steam American Radiator Company, 801, 861-865 Anderson Manufacturing Co., 1054 1055 ' FITTINGS, Pipe, Sweat American Brass Co., The, 972-973 Chase Brass & Copper Co., Incor porated, 974-975, 999 ' Crane Co.. 868-869 Detroit Lubricator Company, 1036 Mueller Brass Co., 976-977. Revere Copper arid Brass Incor porated, 979 Streamline Pipe and Fittings Co.. 976-977 Minneapolis-Honeywell Regulator Company, 1044-1049 GAGE GLASSES American Radiator Company! 801. 861-865 Hays Corporation, 932 Jenkins Bros., 1057 GAGES, Altitude American Radiator Company, 801, 861-865 Bell and Gossett Company, 924-925 Bristol Company, The, 929 Consolidated Ashcroft Hancock Co.. Inc., 931 C. A. Dunham Company, 1012 1013 Hoffman Specialty Co., Inc., 1016 1017 , J. E. Lonergan Co., 1022 Mercoid Corporation, The, 1043 Minneapolis-Honeywell Regulator Company, 1044-1049 New York Air Valve Corporation. 1058 ,. FITTINGS, Welding Bristol Company, The, 929 Taylor Instrument Companies. 936 Consolidated Ashcroft Hancock 937 Crane Co.. 868-869 Co., Inc., 931 United States Gauge Co., 938 - Grinnell Company, Inc., 919-921. Julien P. Friez & Sons, Inc., 1037 Warren Webster & Company, 1028 1015 Hays Corporation, 932 1030 Westinghouse Electric. & Manu J. E. Lonergan Co., 1022 facturing Co., 819, 970 Mercoid Corporation, The, 1043 GAGES, Vacuum . FLOOR AND CEILING PLATES Beaton & Cadwell Mfg. Company, The, 1010-1011 Crane Co., 868-869 New York Air Valve Corporation, 1058 .. Taylor Instrument Companies. 936 937 H. A. Thrush & Co., 926-927 United States Gauge Co., 938 American Radiator Company, 801. 861-865 - Anderson Manufacturing Co., 1054 1055 Bristol Company, The, 929 Brown Instrument Company, 930 FLUE GAS ANALYSIS Hays Corporation, 932 Leeds & Northrup,Company, 934 Minneapolis-Honeywell Regulator Company, 1044-1049 GAGES, Ammonia Baker Ice Machine Co., Inc., 823 Bristol Company, The, 929' . Consolidated Ashcroft Hancock Co., Inc., 931 Consolidated Ashcroft Hancock' Co.; Inc.. 931 , C. A. Dunham Company; 1012 1013 Julien P. Friez & Sons, Inc., 1037 HaysCorporation, 932 Numerals following Manufacturers' Names refer to pages In the Catalog Data Section 1067 LX American Society of Heating and Ventilating Engineers Guide, 1936 Hoffman Specialty Co., Inc., 1016 1017 J. E. Lonergan Co., 1022 . GOVERNORS, Pump Crane Co., 868-869 : C. A. Dunham Company, 1012 Mueller Brass Co., 976-977 Streamline Pipe and Fittings Co., 976-977 Mercoid Corporation, The, 1043 1913 Minneapolis*Honeywell Regulator Foster Engineering Co., 1056 Company, 1044-1049 . Illinois Engineering Company, HEAT CABINETS (See Heaters, Cabinet) New York Air Valve Corporation, . 1018-1019 1058 . Kieley & Mueller, Inc., 1021 HEAT SURFACE, Fan System Taylor Instrument Compames, 936 Mueller Steam Specialty Co., Inc., Aerofin Corporation, 915-917 937 1023 Buckeye Blower Company, 922-923 United States Gauge Co., 938 Warren Webster & Company, 1028 Buffalo Forge Company, 901 Warren Webster & Company, 1028 1030 E. K. Campbell Heating Co., 909 1030 Wright-Austin Co.. 1031 G & O Manufacturing Company, The, 918 GAGES, Vapor GRATES FOR BOILERS AND General Electric Company, 838 American Radiator Company, 801, 861-865 Bristol Company, The, 929 Consolidated Ashcroft Hancock Co., Inc., 931 ' C. A. Dunham Company, 1012 1013 Hoffman Specialty Co., Inc., 1016 1017 o Mercoid Corporation, The, 1043 Minneapolis-Honeywell Regulator Company, 1044-1049 ' FURNACES American Radiator Company, 801, 861-865 Combustion Engineering Company, Inc., 879 . . E. Keeler Company, 883 Lookout Boiler & Mfg. Company, 886-887 L. J. Mueller Furnace Co., 844-845 Unit Heater and Cooler Co., The, 913 839, 968-969 John J. Nesbitt, Inc., 922-923 Niagara Blower Company, 814-815 B. F. Sturtevant Co., 908 . Thermal Units Manufacturing Company, 818 ` Trane Company, The, 1027 Westinghouse Electric & Manu facturing Co., 819, 970 York Ice Machinery Corporation, 820 New York Air Valve Corporation, GRILLES, REGISTERS AND HEATERS, Air 1058 United States Gauge Co., 938 Warren Webster & Company, 1028 1030 . ORNAMENTAL METAL WORK American Blower Corporation, 802 803 Aeriet Air Conditioner Company, 799 Aerofin Corporation, 915-917 American Blower Corporation, 802 GAGES, Water . Auer Register Co., The, 1001 803 . Barber-Colman Company, 1034 Buckeye Blower Company, 922-923 American Radiator Company, 801, 1035 Buffalo Forge Company, 901 861-865 E. K. Campbell Heating Co., 909 E. K. Campbell Heating Co., 909 Baker Ice Machine Co., Inc., 823 Canadian Sirocco Co., Ltd., 802-803 Canadian Sirocco Co., Ltd., 802-803 Bristol Company, The, 929 Brown Instrument Company, 930 Consolidated Ashcroft Hancock Co., Inc., 931 Detroit Lubricator Company, 1036 Julien P. Friez & Sons, Inc., 1037 J. E. Lonergan Co., 1022 Mercoid Corporation, The, 1043 Minneapolis-Honeywell Regulator Co., 1044-1049 Hart & Cooley Manufacturing Co., 1002-1003 Independent Register & Mfg. Co., 1006 ^,, L. J. Mueller Furnace Co., 844-845 Trane Company, The, 1027 Tuttle & Bailey; Inc., 1004-1005 Waterloo Register Company, The, 1007 Carrier Engineering Corporation, 825 Clarage Fan Company, 805 Combustion Engineering Company, Inc., 879 Electric Air Heater Company, 910 Electrol Incorporated, 891 Gar Wood Industries, Inc., 836-837 General Electric Company, 838 839, 968-969 New York Air Valve Corporation, HANGERS, Pipe 1058 Wright-Austin Co., 1031 American Brass Company, The, 972-973 GAS BURNERS Beaton and Cadwell Mfg. Com pany. The, 1010-1011 Babcock & Wilcox Company, The, Chase Brass & Copper Co., Incor 877 or Delco Appliance Corporation, 835, porated, 974-975, 999 Crane Co., 868-869 876.890 - Frick Company (Incorporated), 827 Henry Furnace & Foundry Co., Grinnell Company, Inc., 919-921, 843, 896 _ Spencer Heater Company, 872-873 1015 Ric-wiL Company, The, 963 -Vilter Manufacturing Company, GAS HEATERS' (See Heaters, The. 832 Gas) GASKETS, Asbestos HANGERS, Radiator % Henry Furnace & Foundry Co., 843, 896 Ilg Electric Ventilating Company, 903 McQuay, Incorporated, 812 Meyer Furnace Company, The, 846 John J. Nesbitt, Inc., 922-923 . Niagara Blower Co., 814-815- Norge Division, Borg-Warner Cor poration, 830, 847, 892 B. F. Sturtevant Co., 908 Thermal Units Manufacturing Company, 818 Trane Company, The, 1027 ' Unit Heater and Cooler Co., The, 913 Westinghouse Electric & Manu Crane Co., 868-869 Ehret Magnesia Manufacturing Co.. 946 Jenkins Bros., 1057 Johns-Manville, 950-951 Ruberoid Co., The, 956-957. . GASKETS, Cork Armstrong Cork Products Cora American Radiator Company, 801 861-865 Burnhahi Boiler Corporation, 866 867 Crane Co., 868-869 Grinnell Company, Inc., 919-921, 1015 . National Radiator Corporation, 870-871 facturing Co., 819, 970 York Ice Machinery Corporation, 820 HEATERS, Automatic Hot Water, Domestic American Radiator Company, 801, 861-865 x. Davis Engineering Corporation, . pany, 940 Johns-Manville, 950-951 Mundet Cork Corp., 952 HEADS, Exhaust Burt Mfg. Co., The, 1059 Crane Co., 868-869 928 . Electrol Incorporated, 891 Gar Wood Industries, Inc., 836-837 Henry Furnace & Foundry Co., GASKETS, Rubber Crane Co., 868-869 Ehret Magnesia Manufacturing Co., 946 Frick Company (Incorporated). 827 Jenkins Bros., 1057 Johns-Manville, 950-951 Illinois Engineering Company, 1018-1019 Wright-Austin Co., 1031 HEADS, Sprinkler . Grinnell Company, Inc., 919-921, 1015 843, 896 Sterling Engineering Company, 1026 Williams Oil-O-Matic Heating Cor poration, 848,893 Westinghouse Electric & Manu facturing Co., 819, 970* Please mention THE GUIDE 1936 when writing to Advertisers 1068 Index to Modern Equipment HEATERS, Blast Kewanee Boiler Corporation, 884 National Radiator Corporation. Aeriet Air Conditioner Company, 885 . 870-871 799 Meyer Furnace Company, The, 846 Spencer Heater Company, 872-873 Aerofin Corporation, 915-917 Sterling Engineering Company, American Blower Corporation, 802 HEATERS, Hot Water Service 1026 803 American Radiator Company, 801, Westinghouse Electric & Manu Bayley Blower Company, 900 861-865 facturing Co., 819, 970 Buckeye Blower Company, 922-923 Bell and Gossett Company, 924-925 Buffalo Forge Company, 901 Burnham Boiler Corporation, 866 HEATERS, Unit E. K. Campbell Heating Co., 909 Canadian Sirocco Co., Ltd., 802-803 Carrier Engineering Corporation, 825 Clarage Fan Company, 805 Fedders Manufacturing Co., 911 McQuay, Incorporated, 812 Modine Manufacturing Co., 912 John J. Nesbitt, Inc., 922-923 Niagara Blower Company, 814-815 . Thermal Units Manufacturing Company, 818 . Trane Company, The, 1027 Young Radiator Company, 914 HEATERS, Cabinet Aeriet Air Conditioner Company, 799 American Radiator Company, 801, 861-865 Burnham Boiler Corporation,' 866- 867 Crane Co., 868-869 Electrol Incorporated, 891 Henry Furnace & Foundry Co., 843, 896 Kewanee Boiler Corporation, 884 885 Lookout Boiler & Mfg. Company, 886-887 L. J. Mueller Furnace Co., 844-845 Spencer Heater Company, 872-873 Sterling Engineering Company, 1026 Thermal Units Manufacturing Company, 818 Waterfilm Boilers Incorporated, 888 Williams Oil-O-Matic Heating Cor poration, 848, 893 Westinghouse Electric & Manu facturing Co., 819, 970 Aeriet Air Conditioner Company, 799 American Blower Corporation, 802 803 Bayley Blower Company. 900 Buckeye Blower Company, 922-923 Buffalo Forge Company, 901 Burnham Boiler Corporation, 866 867 E. K. Campbell Heating Co., 909 Canadian Sirocco Co., Ltd., 802-803 Carrier Engineering Corporation, 825 Champion Blower & Forge Co., 902 Clarage Fan Company, 805 C. A. Dunham Company, 1012 1013 Electric Air Heater Company, 910 Fedders Manufacturing Co., 911 Grinnell Company, Inc., 919-921, 1015 867 General Electric Company, 838 HEATERS, Indirect Ilg Electric Ventilating Company, 903 839, 968-969 Aerofin Corporation, 915-917 McQuay. Incorporated, 812 Henry Furnace & Foundry Co., American District Steam Company, Modine Manufacturing Co., 912 843,896 ' 897 National Radiator Corporation, McQuay, Incorporated, 812 American Radiator Company, 801, 870-871 Modine Manufacturing Co., 912 861-865 John J. Nesbitt, Inc., 922-923 Thermal Units Manufacturing . Bell and Gossett Company, 924-925 Niagara-Blower Company, 814-815 ' Company, 818 Betz Unit Air Cooler Co., 804 B. F. Sturtevant Co., 908 Trane Company, The, 1027 E. K. Campbell Heating Co., 909 Thermal Units Manufacturing 'Young Radiator Company, 914 Chase Brass & Copper Co., Incor Company, 818 . HEATERS, - Electric porated, 974-975, 999 Trane Company, The, 1027 Davis Engineering Corporation, Unit Heater and Cooler Co., The, Aeriet Air Conditioner Company, 928 913 799 Electrol Incorporated, 891 L. J. Wing Mfg. Co., 906-907 American Radiator Company, 801, McQuay, Incorporated, 812 Young Radiator Company, 914 861-865 . National Radiator Corporation, Electric Air Heater Company, 910 870-871 HEATERS, Unit, Gas Fired General Electric Company, 838 839, 968-969 Ilg Electric Ventilating Company, 903 B. F. Sturtevant Co., 908 Thermal Units Manufacturing Company, 818 Trane Company, The, 1027 Westinghouse Electric . & Manu facturing Co., 819, 970 ; Young Radiator Company, 914 HEATERS, Feed Water Bell and Gossett Company, 924-925 Sterling Engineering Company, 1026 Thermal Units Manufacturing . Company., 818 HEATERS, Refuse Burning American Radiator Company, 801, 861-865 Kewanee Boiler Corporation, 884 885 Lookout Boiler & Mfg. Company. 886-887 . L. J. Mueller Furnace Co., 844-845 American Radiator Company, 801, 861-865 . Betz Unit Air Cooler Co., 804 . Buffalo Forge Company, 901 - E. K. Campbell Heating Co., 909 L. J. Mueller Furnace Co., 844-845 Trane Company, The, 1027 HEATING SYSTEMS, Air Aeriet Air Conditioner Company, 799 Airtemp Incorporated, 800 American Blower Corporation, 802 803 Carbondale Machine Corporation, 824 Davis Engineering Corporation, 928 ' General Electric Company, 838 839, 968-969 Westinghouse Electric & Manu facturing Co., 819, 970 - HEATERS, Fuel Oil Bell and Gossett Company, 924-925 HEATERS, Storage American District Steam Company. 897 Bell & Gossett Company, 924-925 Burnham Boiler Corporation, 866 867 Davis Engineering Corporation. 928 ' General Electric Company, 838 839, 968-969 American Radiator Company, 801, 861-865 Betz Unit Air Cooler Co., 804 . Buckeye Blower Company, 922-923 Buffalo Forge Company, 901 Canadian Sirocco Co., Ltd., 802-803 Carrier Engineering Corporation, 825 Clarage Fan Company, 805 Delco Appliance Corporation, 835, 876,890 . .Davis 928 Engineering Corporation, HEATERS, Tank Electric Air Heater Company, 910 Electrol Incorporated, 891 General Electric Company, 838 Bell and Gossett Company, 924-925 GarWood Industries, Inc.,.836-837 839 968-969 ' Burnham Boiler Corporation, 866-. General Electric Company, 838 Williams Oil-O-Matic Heating Cor 867 . 839,968-969 . poration, 848, 893 Grinnell Company, Inc., 919-921, Henry Furnace & Foundry Co., HEATERS, Gas American Radiator Company, 801, S6LS65 . Carrier Engineering Corporation, 1015 Kewanee Boiler Corporation, 884 885 Lookout Boiler & Mfg. Company, 886-887 . 843,896 ' Ilg Electric Ventilating Company, 903 Kelvinator Corporation, 808-811 Lookout Boiler & Mfg. Company, .825 L. J. Mueller Furnace Co., 844-845 886-887 ' Numerals following Manufacturers* Names refer to pages in the Catalog Data Section American Society of Heating and Ventilating ,Engineers Guide, 1936 Meyer Furnace Company, The, 846 HEATING SYSTEMS, Hot Gilbert & Barker Mfg. Co., 840-842 Modine Manufacturing Co., 912 - Water . Hoffman Specialty Co., Inc., 1016 L. J.'Mueller Furnace Co., 844-845 John J. Nesbitt, Inc., 922-923 Aeriet- Air Conditioner Company, 799 1017 . Illinois Engineering Company, Niagara Blower Company, 814-815 American Blower Corporation, 802 1018-1019 Reynolds Corporation, 954-955 Thermal Units Manufacturing - 803 American Radiator Company, 801, Lookout Boiler & Mfg. Company, 886-887 ' Co., 818 Trane Company. The, 1027 Unit Heater and Cooler Co., The, 913 Westinghouse Electric & Manu facturing Co., 819, 970 861-865 - Beaton and Cadwell Mfg. Com pany, The. 1010-1011 Bell and Gossett Company. 924-925 Burnham Boiler Corporation, 866 867 L. J. Mueller Furnace.Co., 844-845 National Radiator Corporation, 870-871 Ric-wiL Company, The, 963 Sarco Company, Inc., 1024-1025 Sterling Engineering Company, - L. J. Wing Mfg. Co., 906-907 Young Radiator Company, 914 HEATING SYSTEMS, Auto matic ' Airtemp Incorporated, 800 Burnham Boiler Corporation, 866 867 Delco Appliance Corporation, 835, 876,890 Electrol Incorporated, 891 GarWood Industries, Inc., 836-837 Canadian Sirocco Co., Ltd., 802-803 Crane Co., .868-869 ' Delco Appliance Corporation, 835, 876, 890 Electrol Incorporated, 891 GarWood Industries, Inc., 836-837 General Electric Company, 838 839. 968-969 Gilbert & Barker Mfg. Co., 840-842 Henry Furnace & Foundry Co., 843, 896 Lookout Boiler & Mfg. Company, 1026 . Trane Company, The, 1027 Utica Radiator Corporation, 1000 Warren Webster & Company, 1028 1030 L. J. Wing Mfg. Co., 906-907 HEATING SYSTEMS, Vacuum Aeriet Air Conditioner Company, 799 ` American Radiator Company, 801, General Electric Company, 838-' 839.968-969 Gilbert & Barker Mfg. Co., 840-842 Henry Furnace &' Foundry Co., 843. 896 886-887 L. J. Mueller Furnace Co., 844-845 National Radiator Corporation, 870-871 Parks-Cramer Company, 813 Kelvinator Corporation, 808-811 Meyer Furnace Company, The, 846 L. J. Mueller Furnace Co., 844-845 Norge Division, Borg-Warner Cor poration, 830, 847, 892 Sterling Engineering Company, 1026 H. A. Thrush & Co., 926-927 Trane Company, The, 1027 Utica Radiator Corporation, 1000 Williams Oil-O-Matic Heating Cor poration, 848, 893 L. J. Wing Mfg. Co.. 906-907 861-865 Barnes & Jones, Incorporated, 1014 Bell and Gossett Company, 924-925 Burnham Boiler Corporation, 866 867 Crane Co., 868^869 Delco Appliance Corporation, 835, 876, 890 C. A. Dunham Company, 1012 1013 Electrol Incorporated, 891 Gar Wood. Industries, Inc., 836-837 HEATING SYSTEMS, Furnace American Radiator Company, 801, 861-865 E. K. Campbell Heating Co., 909 Carrier Engineering Corporation, 825 Delco Appliance Corporation, 835, 876, 890 Electrol Incorporated, 891 Gar Wood Industries, Inc., 836-837 General Electric Company, 838 839, 968-969 Gilbert & Barker Mfg. Co., 840-842 Henry Furnace & Foundry Co., 843, 896 Kelvinator Corporation, 808-811 Lookout Boiler '& Mfg. Company, ' 886-887 Meyer Furnace Company, The, 846 L. J. Mueller Furnace Co., 844-845 Norge Division, Borg-Warner Cor poration, 830, 847, 892 HEATING Fired SYSTEMS, Oil General Electric 839; 968-969 Company, 838 William S. Haines & Co., 1020 Airtemp Incorporated, 800 American Blower Corporation, 802 Hoffman Specialty Co. Inc., 1016 1017 -. 803 Illinois Engineering Company,. Bell and Gossett Company, 924-925 Canadian Sirocco Co., Ltd., 802-803 1018-1019 Lookout Boiler & Mfg. Company, Crane Co., 868-869 886-887 Delco Appliance Corporation, 835, L. J. Mueller Furnace Co., 844-845 876. 890 National Radiator Corporation, Electrol Incorporated, 891 870-871 GarWood Industries, Inc., 836-837 New York Air Valve Corporation, General Electric 839, 9681969 Company, 838 ` 1058 Sarco Company, Inc., 1024-1025 Gilbert & Barker Mfg. Co.. 840-842 Sterling Engineering Company, Kelvinator Corporation, 808-811 Meyer Furnace Company, The,.846 1026 . . Trane Company, The, 1027 L. J. Mueller Furnace Co., 844-845 Utica Radiator Corporation, 1000 National Radiator Corporation, 870-871 - Norge Division, Borg-Warner Cor Warren Webster & Company, 1028* 1030 poration, 83Q, 847, 892 * . Trane Company, The, 1027 HEATING SYSTEMS, Vapor HEATING SYSTEMS, Gas Utica Radiator Corporation, 1000 Aeriet Air Conditioner Company, Fired . Airtemp Incorporated, 800 . . HEATING SYSTEMS, Steam 799 American District Steam Company, American Blower Corporation, 80& Aeriet Air Conditioner Company, 897 803 799 ^ American Radiator Company, 801, American Radiator Company, 801, American Radiator Company, 801,' 861-865 861-865 861-865 Barnes & Jones, Incorporated, 1014 Burnham Boiler Corporation, 866- Anderson Manufacturing Co., 1054- Crane Co., 868-869 867 1055 Delco Appliance Corporation. 835, Canadian Sirocco Co., Ltd., 802-803 Barnes & Jones, Incorporated, 1014 876, 890 Carrier Engineering . Corporation, Bell and Gossett Company, 924-925 C. A. Dunham Company, 1012 825 1 ` Burnham Boiler Corporation, 866- 1013 Delco Appliance Corporation, 835, 867 Electrol Incorporated, 891 876, 890 ' E. K. Campbell Heating Co., 909 Gar Wood Industries, Inc., 836-837 General Electric Company, 838- Carrier Engineering' Corporation, General Electric Company, 838 839.968-969 . 825 . * 839, 968-969 Henry Furnace & Foundry -Co., Crane Co., 868-869 ' William S. Haines & Co., 1020 843, 896 Delco Appliance Corporation, 835, Hoffman Specialty Co., Inc., 1016- Lookout Boiler & Mfg. Company, 876, 890 ' 1017 .. 886-887 ' C. A. Dunham Company, 1012- Illinois Engineering Company, Meyer Furnace Company! The, 846 1013 1018-1019 < - L. J. Mueller Furnace Co., 844-845 Electrol Incorporated, 891 Kelvinator Corporation, 80S-S11 National Radiator Corporation, Gar Wood Industries, Inc., 836-837 Lookout Boiler & Mfg. Company, 870-871 ` . General Electric Company. 838- ' 886-887 '_ Trane Company, The, 1027 839, 968-969 , L. J. Mueller Furnace Co., 844-845 Please mention THE GUIDE 1936 when writing to Advertisers , Index to Modern Equipment National Radiator Corporation, HUMIDIFIERS, Unit 870-871 '. New York Air Valve Corporation, 1058 Sarco Company, Inc., 1024-1025 Sterling Engineering Company, 1026 Trane Company.-The, 1027 Utica Radiator Corporation, 1000 Warren Webster & Company, 1028 1030 Aeriet Air Conditioner Company, 799 . . Airtemp incorporated, 800 American Blower Corporation, 802 803 American Moistening Company, 822 - Betz Unit Air Cooler Co., 804 Buffalo Forge Company, 901 Burnham Boiler Corporation, 866 867 HOT WATER HEATING SYS TEMS (See Healing Systems, Hot Water) Canadian Sirocco Co., Ltd., 802-803 Carrier Engineering Corporation, 825 . Clarage Fan Company, 805 HUMIDIFIERS General Electric Company, 838 839,968-969 ' Builders Iron Foundry, 965 Consolidated Ashcroft Hancock Co., Inc., 931 Julien P. Friez & Sons, Inc., 1037 Hays Corporation, 932 Leeds & Northrup Company, 934 Minneapolis-Honeywell Regulator Company, 1044-1049 Powers Regulator Co., The, 1050 1051 Taylor Instrument Companies. 936 937 Westinghouse Electric & Manu facturing Company, 819, 970 INSTRUMENTS, Weather (See Weather Instruments) - Airtemp Incorporated, 800 American Blower Corporation, 802 803 American Moistening Company, 822' American Radiator Company, 801, 861-865 Baker Ice Machine Co., Inc., 823 Buffalo Forge Company, 901 Burnham Boiler Corporation, 866 867 * E. K. Campbell Heating Co., 909 Canadian'Sirocco Co., Ltd., 802-803 Carrier Engineering Corporation, 825 Delco Appliance Corporation, 835, 876, 890 . General Electric Company, 838 839, 968-969 '- Grinnell Company, Inc., 919-921, 1015 Modine Manufacturing Co., 912 L. J. Mueller Furnace Co., 844-845 Grinnell Company. Inc., 919-921, INSULATION, Building 1015 Modine Manufacturing Co., 912 Niagara Blower Company, 814-815 Norge Division, Borg-Warner Cor poration, 830, 847, 892 Parks-Cramer Company, 813 Savage Arms Corporation, 816 B. F. Sturtevant Co., 908 Thermal Units Manufacturing Company, 818 Unit Heater and Cooler Co., The, 913 Westinghouse Electric & Manu facturing Co., 819, 970 . Agasote Millboard Co., The, 939 Alfol Insulation Co., 942-943 Armstrong Cork Products Com pany, 940 Celotex Corporation, The, 944-945 Eagle-Picher Lead Company, The, 941 Ehret Magnesia Manufacturing Co., 946 Insulite Company, The, 948-949 International Fibre Board Limited. 947 Johns-Manville, 950-951 Mundet Cork Corp., 952 HUMIDITY CONTROL Owens-Illinois Glass Company, 854 American Moistening Company, Reynolds Corporation, 954-955 Ruberoid Co.. The, 956-957 American Radiator Company. 801. 861-865 Barber-Colman Company, 1034 1035 Silvercote Products, Inc., 953 Standard Lime & Stone-Company. The. 958 ' United States Gypsum Company, Niagara Blower Company, 814-815 Bristol Company, The, 929 Norge Division, Borg-Warner Cor Brown Instrument Company, 930 Zonolite Corporation, 960-961 poration,. 830. 847, 892 Parks-Cramer Company, 813 Savage Arms Corporation, 816 B. F. Sturtevant Co., 908 Carrier Engineering Corporation, 825 Consolidated Ashcroft Hancock Co., Inc., 931 INSULATION, Pipes and Sur faces (See Covering, Pipes and Surfaces) Thermal Units Manufacturing Detroit Lubricator Company, 1036 Company, 818 Julien P. Friez & Sons, Inc., 1037 INSULATION, Sound Trane Company, The, 1027. ' General Controls. 1042 Deadening ' Unit Heater & Cooler Co., The, 913 General Electric Company, 838 Utica Radiator Corporation, 100Q 839. 968-969 Westinghouse Electric & Manu Grinnell Company. Inc., 919^921, facturing Co., 819, 970 1015 Henry Furnace & Foundry Co., HUMIDIFIERS, Central Plant 843, 896 Airtemp Incorporated, 800 Johnson Service Company. 1040 1041 American Blower Corporation, 803 - Bayley Blower Company, 900 Betz Unit Air Cooler Co., 804 802 * Mercoid Corporation, The, 1043 M inneapolis-Honeywell Regulator Company, 1044-1049 National Regulator Co., 1052 Buffalo Forge Company, 901 Canadian Sirocco Co., Ltd., 802-803 Carrier Engineering Corporation, 825 Niagara Blower Company. 814-815 Parks-Cramer Company, 813' Powers Regulator Co., The, 1050 1051 Clarage Fan Company, 805 Delco Appliance Corporation; 835, Taylor Instrument Companies, 936- 876, 890 Electrol Incorporated, 891 HUMIDITY RECORDERS Alfol Insulation Co., 942-943 Armstrong Cork Products Com pany, 940 Celotex Corporation, The, 944-945 Eagle-Picher Lead Company. The. 941 . Ehret Magnesia Manufacturing Co., 946 ' Insulite Company, The, -948-949 International Fibre Board Limited. 947 Johns-Manville, 950-951 Mundet Cork Corp., 952 Owens-Illinois Glass Company, 854 Ruberoid Co., The, 956-957 Standard Lime & Stone Company. The. 958 Wilson & Co., 962 Zonolite Corporation, 960-961 GarWood Industries, Inc., 836-837 General Electric Company, - 838 839, 968-969 . Bristol Company, The, 929 ' Julien P. Friez & Sons, Inc., 1037 Illinois Testing Laboratories, Inc., INSULATION, Underground Steam Pipe Johnson Service Company, 1040 933 . . Alfol Insulation Co., 942-943 - 1041 Taylor Instrument Companies, 936 American District Steam Company. Meyer Furnace Company.-The, 840` 937 897 Niagara Blower Company, 814-815 Norge Division, Borg-Warner Cor INSERTS, Concrete . poration, 830, 847, 892- * Grinnell Company, Inc., 919-921, Parks-Cramer Company, 813 1015 Powers Regulator Co., The.,-1050- . 1051 INSTRUMENTS, Indicating B. F. Sturtevant Co.; 908 and Recording . York Ice Machinery Corporation, Bristol Company, The, 929 .. .820 Brown Instrument Company, 930 Eagle-Picher Lead Company, The. 941 Ehret Magnesia Manufacturing Company, 946 Johns-Manville, 950-951 ' Owens-Illinois Glass Company, 854 Ric-wiL Company, The, 963 ' Ruberoid Co., The, 956-957 Zonolite Corporation, 960-961 Numerals following Manufacturers* Names refer to pages in the Catalog Data Section 1071 iX American Society of Heating and Ventilating Engineers Guide, 1936 INSULATION, Ventilating Ducts Agasote Millboard Co., The, 939 Alfol Insulation Co., 942-943 Armstrong Cork Products Com pany, 940 Celotex Corporation, The, 944-945 Eagle-Picher Lead Company, The, 941 Ehret Magnesia Manufacturing Company, 946 Insulite Company, The, .948-949 International Fibre Board Limited, 947 Johns-Manville, 950-951 Mundet Cork Corp., 952 Owens-Illinois Glass Company, $54 Ruberoid Co., The, 956-957 Silvercote Products, Inc., 953 ' Wilson & Co., 962 Zonolite Corporation, 960-961 LIQUID LEVEL CONTROLS Bristol Company, The, 929 Foster Engineering Co.', 1056 McDonnell & Miller, 858859 Taylor Instrument Companies, 936 937 LOUVERS Auer Register Co., 1001 Buffalo Forge Company, 901 Burt Mfg. Co., The, 1059 Clarage Fan Company. 805 General Controls, 1042 ' Henry Furnace & Foundry Co., 843, 896 Trane Company, The, 1027 Tuttle & Bailey, Inc., 1004-1005 Waterloo Register Company, The, 1007 Young Ventilating Company, The, 849 MAGAZINES (.See Publications) MANHOLE COVERS, For Underground Systems . American District Steam Company, 897 Ric-wiL Company, The, 963 MECHANICAL DRAFT APPAR ATUS {See Blowers, Forced Draft) METERS, Air Builders Iron Foundry, 965 Julien P. Friez & Sons, Inc., 1037 Hays Corporation, 932 Minneapolis-Honeywell Regulator Company, 1044-1049 Taylor Instruments Companies, 936-937 METERS, Air Velocity Anderson Manufacturing Co., 1054 1055 Julien P. Friez & Sons, Inc., 1037 Hays Corporation, 932 Illinois Testing Laboratories Inc., 933 Minneapolis-Honeywell Regulator Company, 1044-1049 ' Powers Regulator Co., The, 1050: 1051 . Taylor Instrument Companies, 938 937 METERS, Condensation American District Steam Company, 897 ' Carbondale Machine Corporation, 824 METERS, Feed Water ORIFICES, Flow Meter Builders Iron Foundry, 965 Bristol Company, The, 929 Carbondale Machine Corporation, Builders Iron Foundry, 965 824 Taylor Instrument Companies, 938 Minneapolis-Honeywell Regulator 937 Co., 1044-1049 , ORIFICES, Radiator METERS, Flow Barnes & Jones, Incorporated, 1014 Brown Instrument Company! 930 Bell and Gossett Company, 924-925 Builders Iron Foundry, 965 Detroit Lubricator Company, 1036 Hays Corporation, 932 C. A. Dunham Company, 1012 Leeds & Northrup Company, 934 1013 Minneapolis-Honeywell Regulator Hoffman Specialty Co., Inc., 1018 Co., 1044-1049 1017 Taylor Instrument Companies, 938 New York Air Valve Corporation, 937 1058 METERS, Steam Sterling ` Engineering Company, 1026 American District Steam Company, H. A. Thrush & Co.. 926-927 897 Trane Company, The, 1027 Builders Iron Foundry, 965 Warren Webster & Company, 1028 Minneapolis-Honeywell Regulator 1030 Co., 1044-1049 Taylor Instrument Companies, 936 PACKING, Asbestos 937 METERS, Water Ehret Magnesia Manufacturing Co. 946 Johns-Manville, 950-951 Builders Iron Foundry, 965 Carbondale Machine Corporation, PANELS, Insulated , 824 Celotex Corporation, The, 944-945 Minneapolis-Honeywell Regulator Insulite Company, The, 948-949 Co., 1044-1049 International Fiber Board Limited, 947 MOTORS, Electric United States Gypsum Company, Baldor Electric Co., 966 Barber-Colman Company, 1034 959 Zonolite Corporation, 960-961 1035 Century Electric Company, 967 Delco Appliance Corporation, 835, 876. 890 - General Electric Company, 838 839,968-969 . B. F. Sturtevant Co., 908 Westinghouse Electric & Manu facturing Co., 819, 970 PIPE, Asbestos Eagle-Picher Lead Company, The, 941 Ehret Magnesia Manufacturing Co., 946 Johns-Manville, 950-951 Standard Lime & Stone Company, The, 958 Williams Oil-O-Matic Heating Cor PIPE, Brass poration, 848, 893 American Brass Company, The, NOZZLES, Sandblast 972-973 Chase Brass & Copper Co. Incor American Foundry Equipment Co., porated, 974-975, 999 The, 910 Crane Co., 868-869 NOZZLES, Nozzles) Spray. (See ' Spray Mueller Brass Co., 976-977 Revere Copper and Brass Incor porated, 979 . OIL BURNER EQUIPMENT Streamline Pipe and Fittings Co., Crane Co., 868-869 Delco Appliance Corporation, $35, 976-977 Wolverine Tube Company, 980 876, 890 Detroit Lubricator Company, 1036 PIPE, Cement Electrol Incorporated, 891 Eagle-Picher Lead Company, The, General Electric Company, 838 941 839,968-969 ... Johns-Manville, 950-951- Gilbert & Barker Mfg. Co;^840-842 Ruberoid Co.. The, 956-957 Norge Division, Borg-Warner Cor Standard Lime & Stone Company, poration, 830, 847, 892 The, 958 Williams Oil-O-Matic Heating Cor poration, 848, 893 PIPE, Copper OIL BURNERS - American Brass Company, The, 972-973 Airtemp Incorporated, 800 Chase Brass & Copper Co. Incof- Babcock & Wilcox Company, The, porated, 974-975; 999 877 ' Crane Co., 868869 Delco Appliance Corporation, 835, Mueller Brass Co., 976-977 876, 890 Revere Copper and Brass Incor Electrol Incorporated, 891 porated, 979 Gar Wood Industries, Inc., 836-837 Streamline Pipe and Fittings Co., General Electric Company, 838 976-977 839, 968-969 Wolverine Tube Company, 980 Gilbert & Barker Mfg. Co., 840-842 Kelvinator Corporation, 808-811 PIPE, Copper Bearing Steel Norge Division, Borg-Warner Cor Crane Co., 868-869 poration, 830, 847; 892 Jones & Laugblin Steel Corpora Williams Oil-O-Matic Heating Cor tion, 971 ' poration, 848, 893 Republic Steel Corporation, 978 Please mentlcin THE GUIDE 1936 when writing to Advertisers 1072 Index to Modern Equipment Pipe, Copper Molybdenum Iron PLASTER BASE, Insulating Ingersoll-Rand Company, 828829 Republic Steel Corporation, 978 PIPE, Return Bends Carbondale Machine Corporation, 824 Agasote Millboard Co., The, 939 Armstrong Cork Products' Com pany, 940 Celotex Corporation, The, 944-945 Insulite Company, The, 948-949 Nash Engineering Company, 994 995 ' PUMPS, Ammonia American Steam Pump Company! Crane Co., 868869 International Fibre Board Limited, Frick Company (Incorporated), 827 947 Grinnell Company, Inc., 919-921, Johns-Manville, 958951 Carbondale Machine Corporation. 824 1015 United States Gypsum Company, York Ice Machinery Corporation. Mueller Brass Co., 978977 959 820 Streamline Pipe and Fittings Co., Zonolite Corporation, 968961 978977 PUMPS, Boiler Feed Vilter Manufacturing Company, PLASTER BASE, Sound The, 832 Deadening American Steam Pump Company, Wolverine Tube Company, 980 PIPE, Steel Crane Co., 868869 Jones & Laughlin Steel Corpora tion, 971 Republic Steel Corporation, 978 Vilter Manufacturing: Company, The, 832 Agasote Millboard Co., The, 939 Armstrong Cork Products Com pany, 940 Celotex Corporation, The, 944-945 Insulite Company, The, 948949 International Fibre Board Limited, 947 Johns-Manville, 958951 United States Gypsum Company, Carbondale Machine Corporation; 824 Chicago Pump Company, 992-993 Decatur Pump Company, 996 . Ingersoll-Rand Company, 828829 John H. McGowan Company. The. 997 Nash Engineering Company. 994 995 . PIPE, Wrought Iron Crane Co., 868869 Vilter Manufacturing The, 832 Company, 959 Zonolite Corporation, 968961 PLATES, Copper MolybdenumIron Sterling Engineering Company. 1026 Trane Company, The, 1027 Westco Pump Corporation, 998 Westinghouse Electric & Manu PIPE ANCHORS Republic Steel Corporation, 978 facturing Co., 819, 970 . Crane Co., 868-869 Grinnell Company, Inc., 919-921, 1015 Underground Steam Construction Co., 964 PLATES,' Stainless Steel Republic Steel Corporation, 978 PLATES, Steel PUMPS, Brine American Steam Pump Company, 991 . Carbondale Machine Corporation. 824 ' PIPE BENDING " Crane Co., 868-869 Frick Company (Incorporated), 827 Grinnell Company, Inc., 919-921, 1015 Vilter Manufacturing Company, The, 832 Jones & Laughlin Steel Corpora tion, 971 Republic Steel Corporation, 978 PRESSURE REDUCING VALVES (See Regulators, Pres sure) Chicago Pump Company, 992-993 Frick Company (Incorporated). 827 Ingersoll-Rand Company, 828829 John H. McGowan Company. The, 997 Nash Engineering Company, 994 995 . Trane Company, The, 1027 PIPE COILS (See Coils, Pipe) PROPELLER FANS {See Fans, Westco Pump Corporation, 998 PIPE CONDUITS (See Conduits, Underground Pipe) PIPE COVERING (See Covering, Pipe) PIPE FITTINGS (See Fittings, Pipe) , . Propeller) PUMPS, Centrifugal PSYCHROMETERS {See American Steam Pump Company, Air 991 Measuring and Recording Instru Bell and Gossett Company, 924-925 ments) Carbondale Machine Corporation, PUBLICATIONS 824 Chicago Pump Company, 992-993 American Artisan, 982 Decatur Pump Company, 996 American Society of Refrigerating C. A. Dunham Company, 1012 PIPE GUIDES . Crane Co., 868869 ' Ric-wiL Company, The', 963 Underground Steam Construction Co., 964 Engineers, 981 Automatic Heat and Air ditioning, 984 Domestic Engineering, 985 Fueloil Journal. 986 Heating & Ventilating, 987 Con ' 1013 Frick Company (Incorporated), 827 Ingersoll-Rand Company, 828829 John H. McGowan Company, The, 997 Nash Engineering Company, 994 PIPE HANGERS Pipe) ' , {See Hangers, .' Heating, Piping ditioning, 983 Oil Heat, 988 and. Air . Con 995 . Trane Company, The, 1027 Westco Pump Corporation, 998 . . PIPE SUPPORTS, For Under ground Conduit . American District Steam Company, 897 Ric-wiL Company, The, 963 .' Underground Steam Construction Co., 964 Plumbing and Heating Trade- Journal, 989 . . PUMPS, Circulating Sheet Metal Worker, 990 American Steam Pump Company, 991 PULLEYS, Chain Bell and Gossett Company, 924 Hart & Cooley Manufacturing Co., 925 . 1002-1003 Carbondale Machine Corporation, 824 " PITOT TUBES (See Air Measuring and Recording Instruments) PUMP GOVERNORS (See Cover- . nors, Pump) ' Chicago Pump Company, 992-993 Decatur Pump Company, 996 Ingersoll-Rand Company, 828829 PLASTER BASE, Fire Retarding Agasote Millboard Co., The, 939 Armstrong Cork Products Com pany, 940 ' Johns-Manville, 958951 United States Gypsum Company. 959 Zonolite Corporation, 968961 PUMPS, Air arid Gas American Steam Pump Company, Carbondale Machine Corporation, 824 . : . Curtis Refrigerating Machine Com pany, Division of Curtis Manu facturing Company, 826 John H. McGowan'Company, The, 997 Nash Engineering Company, 994 995 Sterling Engineering Company, 1026 H. A. Thrush & Co.. 928927 Trane Company, The, 1027 . Westco Pump Corporation, 998 Numerals following Manufacturers* Names refer to pages in the Catalog Data Section ^ 1073 V'S; 1 : 1936American Society of Heating and Ventilating Engineers Guide, PUMPS, Condensation. American Steam Pump Company, 991 Carbondale Machine Corporation, Chicago Pump Company, 992-993 Decatur Pump Company, 996 C. A. Dunham Company, 1012 1013 Hoffman Specialty Co., Inc., 1016 1017 - Ingersoll-Rand Company, 828-829 John H. McGowan Company, The, 997 Nash Engineering Company, 994 995 . Sterling Engineering Company, 1026 Trane Company, The, 1027 John H. McGowan Company, The, 997 Nash Engineering Company, 994 995 Sterling Engineering Company. 1026 Trane Company, The, 1027 PYROMETERS, Portable and Stationary Bristol Company, The, 929 Brown Instrument Company, 930 Hays Corporation, 932 Illinois Testing Laboratories Inc., 933 Leeds & Northrup Company, 934 Minneapolis-Honeywell Regulator Company, 1044-1049 Taylor instrument Companies. 936 G & O Manufacturing Company, The. 918 General Electric Company, 838 839, 968-969 Grinnell Company, Inc., 919-921, 1015 McQuay, Incorporated, 812 National Radiator Corporation, 870-871 B. F. Sturtevant Co., 908 Trane Company, The, 1027 Utica Radiator Corporation, 1000 Young Radiator Company, 914 RADIATION, Steel Trane Company, The, 1027 RADIATOR AIR VALVES (See Valves, A ir) - Westco Pump Corporation, 998 937 . RADIATOR ENCLOSURES PUMPS, Oil RADIATION, Aluminum AND SHIELDS American Steam Pump Company, 991 Carbondale Machine Corporation, 824 Ingersoll-Rand Company, 828-829 John H. McGowan Company, The, 997 Westco Pump Corporation, 998 PUMPS, Steam American Steam Pump Company, Aeriet Air Conditioner Company, 799 Aerofin Corporation. 915-917 McQuay, Incorporated. 812 Thermal Units Manufacturing Company, 818 Trane Company, The, 1027 Unit Heater and Cooler Co., The, 913 Warren Webster & Company, 1028 1030 American Radiator Company, 801, 861-865 . Auer Register Co., The, 1001 Modine Manufacturing Co., 912 Revere Copper and Brass Incor porated, 979 RADIATOR HANGERS (See Hangers, Radiator) RADIATORS, Cabinet American Radiator Company, 801, 991 Carbondale Machine Corporation, 824 Ingersoll-Rand Company, 828-829 John H. McGowan Company,- The, 997 Trane Company, The, 1027 RADIATION, Brass Fedders Manufacturing Co., 911 G & O Manufacturing Company, The. 918 ' McQuay, Incorporated. 812 Revere Copper and Brass Incor porated, 979 PUMPS, Sump RADIATION, Cast-Iron American Steam Pump Company, American Radiator Company, 801, 991 Carbondale- Machine Corporation, 861-865 Burnham Boiler Corporation, 866 824' Chicago Pump Company, 992-993' Ingersoll-Rand Company, 828-829 John H. McGowan Company, The, 867 Crane Co., 868-869 National Radiator 870-871 ' Corporation, 997 Nash Engineering Company, 994 995 ` Unit Heater and Cooler Co., The, 938 United States Radiator Corpora 861-865 * Buckeye Blower Company, 922-923 Burnham Boiler Corporation, 866 867 Chase Brass & Copper Co. Incor porated, 974-975, 999 C. A. Dunham Company, 1012 1013 . Grinnell Company, Incorporated, 919-921, 1015 McQuay, Incorporated, 812 National Radiator Corporation, 870-871 John J. Nesbitt, Inc., 922-923 Thermal Units Manufacturing Company, 818 Trane Company, The, 1027 Unit Heater and Cooler Co., The, 913 United States Radiator Corpora PUMPS, Turbine tion, 874 * tion, 874 Utica Radiator Corporation, 1000 Warren Webster & Company, 1028 American Steam Pump Company, Weil-McLain Company, 875 991 Carbondale Machine Corporation, RADIATION, Copper 1030 Weil-McLain Company, 875 Young Radiator Company, 914 824 Decatur Pump Company, 996 Hoffman Specialty Co., Inc., 1016 1017 Ingersoll-Rand Company, 828-829 John H. McGowan Company, The, 997 * Nash Engineering Company, 994 995 Westco Pump Corporation, 998 Aerofin Corporation, 915-917 Buckeye Blower Company, 922-923 Chase Brass & Copper Co. Incor porated, 974-975, 999 C. A. Dunham Company, 1012 1013 N Fedders Manufacturing Co., 911 G & O Manufacturing Company, The, 918 McQuay, Incorporated, 812 Modine Manufacturing Co., 912 RADIATORS, Concealed Buckeye Blower Company, 922-923 Burnham Boiler Corporation, 866- 867 Chase Brass & Copper Co. Incor porated, 974-975, 999 Crane Co., 868-869 C. A. Dunham Company, 1012 Gr1in0n13ell Company, Inc., 919-,921. , . PUMPS, Vacuum American Steam Pump Company, 991 Bell and Gossett Company, 924-925 Carbondale Machine Corporation, 824 Chicago Pump Company, 992-993 Curtis Refrigerating Machine Com pany, Division of Curtis Manu facturing Company, 826 C; A. Dunham Company, 1012 1013 Hoffman Specialty Co., Inc., 1016 1017 Ingersoll-Rand Company, 828-829 John J. Nesbitt, Inc., 922-923 1015 Revere Copper and Brass Incor McQuay, Incorporated, 812 porated, 979 Modine Manufacturing Co., 912 B. F. Sturtevant Co., 908 National Radiator Corporation, Trane Company, The, 1027 Tuttle & Bailey Inc., 1004-1005 870-871 John J. Nesbitt, Inc., 922-923 Young Radiator Company, 914 * Revere Copper and Brass Incor porated, 979 RADIATION, Plain and Ex Thermal Units Manufacturing- ' tended Surface Company, 818 . Aeriet Air Conditioner Company, Trane Company, The, 1027 799 Unit Heater and Cooler Co., The, Aerofin Corporation, 915-917 913 ' Crane Co., 868-869 United States Radiator Corpora- Fedders Manufacturing Co., 911 tion, 874 * . Please mention THE GUIDE 1935 when writing to Advertisers 1074 Index to Modern Equipment Warren Webster & Company, 1028 1030 Weil-McLain Company, 875 Young Radiator Company, 914 REFRIGERATION EQUIP MENT, Water Vapor Ingersoll-Rand Company. 828-829 REGULATORS, Feed Water Beaton & Cadwell Mfg. Company*. The, 1010-1011 Foster Engineering Co., 1056 RECEIVERS, Air REFRIGERATING MACHINERY Kieley & Mueller, Inc., 1021 McDonnell & Miller, 858-859 Baker Ice Machine Co., Inc., 823 Curtis Refrigerating Machine Com pany, Division Curtis Manu facturing Company, 826. Farrar & Trefts, Incorporated, 882 Illinois Engineering Company, ' 1018-1019 Ingersoll-Rand Company, 828-829 Aeriet Air Conditioner Company. 799 - . Airtemp Incorporated, 800 Baker Ice Machine Co., Inc., 823 Carbondale Machine Corporation. 824 Carrier Engineering Corporation, Mueller Steam- Specialty Co.. Inc1023 Powers Regulator Co., The, 1050 1051 H. A. Thrush & Co., 926-927 Westinghouse Electric & Manu facturing Co., 819, 970 Wright-Austin Co., 1031 Kewanee Boiler Corporation, 884 885 Parks-Cramer Company, 813 Trane Company, The, 1027 Warren Webster & Company, 832 RECEIVERS, Ammonia * Frick Company (Incorporated), 827 Curtis Refrigerating Machine Com pany, Division of Curtis Manu REGULATORS, Furnace facturing Company, 826 ' Air Controls, Inc., 834 Frick Company (Incorporated). 827 Hart & Cooley Manufacturing Co.. Frigidaire Corporation, 806-807 1002-1003 General Electric Company, 838 Henry Furnace & Foundry Co- 839, 968-969 843. 896 Ingersoll-Rand Company, 828-829 York Ice Machinery Corporation, 820 Kelvinator Corporation, 808-811 Norge Division, Borg-Wamer Cor poration, 830, 847, 892 REGULATORS, Humidity (See Humidity Control) RECEIVERS, Condensation American Steam Pump Company, 991 Baker Ice Machine Co., Inc., 823 Carbondale Machine Corporation, 824 Chicago Pump Company, 992-993 Crane Co., 868-869 Illinois Engineering Company; 1018-1019 Nash Engineering Company, The, Servel, Inc., 817 B. F. Sturtevant Co., 908 Thermal Units Manufacturing Co., 818 Universal Cooler Corporation, 831 Vilter Manufacturing Company, The. 832 Westinghouse Electric & Manu facturing Co., 819, 970 York Ice Machinery Corporation, 820 REGULATORS, Pressure American Radiator Company, 801, 861-865 Beaton & Cadwell Mfg. Company. The, 1010-1011 Bristol Company, The, 929 Consolidated Ashcroft Hancock Co., Inc., 931 Crane Co., 868-869 Detroit Lubricator Company, 1036 C. A. Dunham Company, 1012 994-995 ' Sarco Company, Inc.. 1024-1025 Trane Company, The, 1027 REGISTERS (5<e GrtW, etc.) 1013 Fedders Manufacturing Co.. 911 Foster Engineering Co., 1056 Warren Webster & Company, 1028 1030 Westco Pump Corporation, 998 REGULATORS, Air Volume Young Ventilating Company, The, 849 Frigidaire Corporation, 806-807 Fulton Sylphon Co., 1038-1039 ` General Controls, 1042 . General Electric Company, 838 RECEIVERS, Water Vapor American Blower Corporation, 802 803 Bell and Gossett Company, 924-925 Canadian Sirocco Co.. Ltd., 802-803 Trane Company, The, 1027 Warren Webster & Company, 1028 1030 RECORDERS, Humidity, Tem perature Julien P. Fries & Sons, Inc., 1037 Johnson Service Company, 1040 ... 1041 , National Regulator Co- 1052 Powers Regulator Co., The, 1050 REGULATORS, Damper American Radiator Company, 801. 861-865 Barber-Colman Company, 1034 1035 E. K. Campbell Heating Co., 909 Carrier Engineering Corporation, 825 Detroit Lubricator Company, 1036 C. A. Dunham Company, 1012 1013 Foster Engineering Co., 1056 Fulton Sylphon Co., 1038-1039 General Controls, 1042 General Electric Company, 838 839, 968-969 839,968-969 Hays Corporation, 932 Henry Furnace & ` Foundry Co- 843, 896 Illinois Engineering Company, 1018-1019 Kieley & Mueller, Inc., 1021 Minneapolis-Honeywell Regulator Company, 1044-1049 Mueller Steam Specialty Co., Inc., 1023 . Powers Regulator Co., The, 1050 1051 . Taylor Instrument Companies, 930 937 ' H. A. Thrush & Co., 926-927 1051 . Taylor Instrument Companies, 936 937 . ' William S. Haines & Company, 1020 Hart & Cooley Manufacturing Co., REGULATORS, Temperature (See Temperature Control) REFRIGERATING EQUIP MENT, Centrifugal 1002-1003 Hays Corporation, 932 Henry Furnace & Foundry Co., RELIEF VALVES ' (S Relief) Valves. Carrier Engineering Corporation. 825 . Ingersoll-Rand Company, 828-829 REFRIGERATING EQUIP MENT, Steam Jet 843, 896 Hoffman Specialty Co., Inc., 1016 1017 Illinois Engineering Company, 1018-1019 Johnson Service Company, 1040 1041 SAFETY VALVES (See Valves. Safety) SANDBLAST EQUIPMENT American Foundry Equipment Co., The, 910 American Blower Corporation, 802 Kieley & Mueller, Inc., 1021 803 Leeds & Northrup Company, 934 SEPARATORS, Dust Canadian Sirocco Co., Ltd., 802-803 Carbondale Machine Corporation. 824 Carrier Engineering Corooration, 825 . Ingersoll-Rand Company, 828-829 Westinghouse Electric & Manu facturing Co., 819, 970 Williams Oil-O-Matic Heating Cor poration, 848, 893 . Minneapolis-Honeywell Regulator Company, 1044^1049 National Regulator Co., 1052 Powers Regulator Co., The., 1050 1051 H. A. Thrush & Co., 926-927 Trane Company, The, 1027 Tuttle & Bailey, Inc., 1004-1005 Warren Webster & Company, 1028 1030 American Air Filter Company Inc., 850851 . American Blower Corporation, 802 803 Buffalo Forge Company, 901 Canadian Sirocco Co., Ltd., 802-803' Coppus Engineering Corporation, 852 ... Unit Heater and Cooler Co., The: 913 Numerals following Manufacturers' Names refer to pages in the Catalog Data Section 1075 American Society of Heating and Ventilating Engineers Guide, 1936 SEPARATORS, Oil Crane Co-, 868-869 Frick Company (Incorporated), 827 Illinois Engineering Company, 1018-1019 Kieley & Mueller, Inc., 1021 Warren Webster & Company, 1028 1030 Wright-Austin Co., 1031 SMOKE DENSITY RECORDING . Brown Instrument Company, 930 Leeds & Northrup Company, 934 Westinghouse Electric & Manu facturing Co., 819, 970 SOOT DESTROYER Vinco Company, Inc.., The, 857 Warren Webster & Company, 1028 1030 Wright-Austin Co., 1031 Zonolite-Corporation, 960-961 STRAINERS, Oil Crane Co., 868-869 Detroit Lubricator Company, 1036 Foster Engineering Co., 1056 General Controls, 1042 SEPARATORS. Steam SOUND DEADENING General Electric Company, 838 839. 968-969 Crane Co., 868-869 Agasote Millboard Co., The, 939 Illinois Engineering Company, ` Illinois Engineering Company, Alfol Insulation Co., 942-943 1018-1019 1018-1019 Armstrong Cork Products Com Kieley & Mueller, Inc., 1021 Kieley & Mueller, Inc., 1021 pany, 940 Mueller Steam Specialty Co., Inc., Warren Webster & Company, 1028 Celotex Corporation, The. 944-945 1023 1030 Eagle-Picher Lead Company, The, Sarco Company, Inc., 1024-1025 Wright-Austin Co., 1031 941 Wright-Austin Co., 1031 Insulite Company, The, 948-949 SHEETS, Aluminum Foil Alfol Insulation Co., 942-943 Reynolds Corporation, 954-955 International Fibre Board Limited, 947 , Johns-Manville, 950-951 . Mundet Cork Corp., 952 STRAINERS, Steam Crane Co., 868-869 Detroit Lubricator Company, 1036 SHEETS, Asbestos, Flat and Ruberoid Co., The, 956-957 Foster Engineering Co.. 1056 Corrugated Reynolds Corporation, 954-955 General Controls, 1042 Eagle-Picher Lead Company, The, 941 Ehret Magnesia Manufacturing Co 946 Johns-Manvilie, 950-951 Ruberoid Co., The, 956-957 Standard Lime & Stone Company, The, 958 United States Gypsum Company, 959 Zonolite Corporation, 960-961 SPRAY NOZZLES Illinois Engineering Company, 1018-1019 Kieley & Mueller, Inc.,. 1021 Mueller Steam Specialty Co., Inc., 1023 Powers Regulator Co., The, 1050 1051 SHEETS, Black, Galvanized Corrugated, American Blower Corporation, 802 803 Sarco Company, Inc., 1024-1025 Wright-Austin Co., 1031 Republic Steel Corporation, 978 Baker Ice Machine Co., Inc., 823 SHEETS, Copper Bayley Blower Company, 900 Buffalo Forge Company, 901 STRAINERS, Water . Betz Unit Air Cooler Co., 804 American Brass Company, The, Canadian Sirocco Co., Ltd., 802-803 Crane Co., 868-869 972-973 Clarage Fan Company, 805 Detroit Lubricator Company, 1036 Chase Brass & Copper Co. Incor Detroit Lubricator Company, 1036 Foster Engineering Co., 1056 porated, 974-975, 999 Mueller Brass Co., 976-977 General Controls, 1042 . Revere Copper and Brass Incor-, Streamline Pipe and Fittings Co., Kieley & Mueller, Inc., 1021 porated, 979 976-977 Mueller Steam Specialty Co., Inc., SHEETS, Copper Alloy . B. F. Sturtevant Co., 908 Trane Company, The, 1027 1023 Powers Regulator Co., The, 1050 American Brass Company, The, York Ice Machinery Corporation, 1051 ~. 972-973 820 Sarco Company, Inc.,1024-1025 Chase Brass & Copper Co. Incor porated, 974-975, 999 STACKS, Steel Wright-Austin Co., 1031 Revere Copper and Brass Incor E. Keeler Company, 883 porated, 979 TANK COILS (See Coils, Tank) STATIONARY PYROMETERS TANK COVERING (See Covering, SHEETS, Copper Bearing Steel (See Pyrometers) Pipes and Surfaces) Republic Steel Corporation, 978 STEAM HEATING SYSTEMS TANK HEATERS (See Healers, SHEETS, Copper Molybdenum (See Healing Systems Steam) Tank) ' . Iron - Republic Steel Corporation, 978 SHEETS, Lead Coated Copper American Brass Company, The, 972-973 Chase Brass & Copper Co. Incor porated, 974-975, 999 ' Revere Copper and Brass Incor porated, 979 SHEETS, Special Finish STOKERS, Mechanical Babcock & Wilcox Company, The, 877 Combustion Engineering Company, Inc., 879 . Detroit Stoker Company.,1032 Iron Fireman Manufacturing Com pany, 894-895 Whiting Corporation, 1033 Westinghouse Electric & Manu facturing Co., 819, 970 . TANKS, Blow-off Bigelow Company, The, 878 Farrar & Trefts Incorporated, 882 Kewanee Boiler Corporation, 884 885 TANKS, Pressure 1 Bell and Gossett Company, 924-925 Bigelow Company, The, 878 Burnham Boiler Corporation, 866 867 - Republic Steel Corporation, 978 STRAINERS, Dirt SHEETS, Steel Republic Steel Corporation, 978 Crane Co., 868-869 . Detroit Lubricator Company, 1036 C. A. Dunham Company, 1012 SHUTTERS, Automatic ` 1013 General Controls, 1042 Barber-Colman Company, 1034- Hoffman Specialty Co., Inc., 1016 1035 1017 E. K. Campbell Heating Co., 909 . Illinois Engineering Company, Champion Blower & Forge Co.,.902 1018-1019 Ilg Electric Ventilating Company, Mheller Steam Specialty Co., Inc., 903 ' B. F. Sturtevant Co., 908 1023 Sarco Company, Inc., 1024-1025 Young Ventilating Company, The, Sterling Engineering Company, 849. ' ' 1026 .* Farrar & Trefts Incorporated, 882 Frick Company (Incorporated), 827 Kewanee Boiler Corporation, 884 885 H. A. Thrush & Co., 926-927 TANKS, Storage Bigelow Company, The, 878 Burnham BoUer Corporation, 866 867 \ Farrar & Trefts, Incorporated, 882 Frick Company (Incorporated), 827 Gilbert & Barker Mfg. Co., 840-842 Kewanee Boiler Corporation, 884 - 885 . Please mention THE GUIDE 1936 wheh writing to Advertisers 1076 Index to Modern Equipment - temperature control Minneapolis-Honeywell Regulator Sterling Engineering - Company, American Radiator Company, 801, Company, 1044-1049 861-865 Palmer Company, The, 935 1026 . Trane Company, The, 1027 . Barber-Colman 1035 Company, 1034 Powers Regulator Co., The, 1050 1051 Warren Webster & Company, 1028 1030 , Bristol Company, The, 929 Sarco Company, Inc., 1024-1025 Wright-Austin Co., 1031 Builders Iron Foundry, 965 Taylor Instrument Companies, 936 Carrier Engineering Corporation, 825 Consolidated Ashcroft Hancock Co., Inc., 931 Detroit Lubricator Company, 1036 Dole Valve Company, The, 1053 C. A. Dunham Company, 1012 1013 Foster Engineering Co., 1056 Julien P. Friez & Sons, Inc., 1037 Frigidaire Corporation, 806-807 Fulton Sylphon Co., 1038-1039 General Controls, 1042 General Electric Company, 838 839, 968-969 Hays Corporation, 932 Henry Furnace & Foundry Co., 843, 896 Hoffman Specialty Co., Inc., 1016 1017 Illinois Engineering Company, 1018-1019 Johnson Service Company, 1040 1041 937 H. A. Thrush & Co., 926-927 United States Gauge Co., 938 THERMOMETERS, Recording Bristol Company, The, 929 Brown Instrument Company, 930 Builders Iron Foundry, 965 Consolidated Ashcroft Hancock Co.. Inc., 931 Julien P. Friez & Sons, Inc., 1037 Leeds & Northrup Company, 934 Minneapolis-Honeywell Regulator Company, 1044-1049 Powers Regulator Co., The, 1050 1051 Taylor Instrument Companies, 936 937 H. A. Thrush & Co., 926-927 THERMOSTATS American Radiator Company, 801, 861-865 .' TRAPS, Float and Thermostatic Armstrong Machine Works, 1008 1009 Barnes & Jones, Incorporated, 1014 C. A. Dunham Company, 1012 1013 Grinned Company, Inc., 919-921, 1015 William S. Haines & Company, 1020 Hoffman Specialty Co., Inc., 1016 1017 . Illinois Engineering Company, 1018-1019 Mueller Steam Specialty Co., Inc., 1023 Sarco Company, Inc., 1024^1025 Sterling Engineering Company, 1026 Trane Company, The, 1027 Warren Webster & Company, 1028 1030 . Wright-Austin Co., 1031 Leeds & Northrup Company, 934 Mercoid Corporation, The, 1043 Barber-Colman 1035 Company, 1034 TRAPS, Radiator Minneapolis-Honeywell Regulator Bristol Company, The, 929 Armstrong Machine Works, 1008 Company, 1044-1049 Carrier Engineering Corporation, 1009 National Regulator Co., 1052 825 Barnes & Jones; Incorporated, 1014 Powers Regulator Co., The, 1050 Consolidated Ashcroft Hancock C. A. Dunham Company, 1012 1051 Co.. Inc., 931 1013 Sarco Company, Inc., 1024-1025 Detroit Lubricator Company, 1036 William S. Haines & Company, Sterling Engineering Company, Julien P. Friez & Sons, Inc., 1037 1026 Fulton Sylphon Co., 1038-1039 1020 Hoffman Specialty Co., Inc., 1016 Taylor Instrument Companies, 936 General Controls, 1042 1017 937 General Electric Company, 838 Illinois Engineering Company, Thermal Units Manufacturing. 839, 968-969 1018-1019 . Company, 818 ' Johnson Service Company, 1040 Sarco Company, Inc., 1024-1025 Trane Company, The, 1027 1041 Sterling Engineering Company, Warren Webster & Company, 1028 Mercoid Corporation, The, 1043 ' 1026 1030 Minneapolis-Honeywell Regulator Trane Company, The, 1027 Westinghouse Electric & Manu Company, 1044-1049 Warren Webster & Company, 1028 facturing Co., 819, 970 National Regulator Co., 1052 1030 L. J. Wing Mfg. Co., 906-907 Powers Regulator Co., .The, 1050 1051 TRAPS, Return THERMOMETERS, Distance Type Sarco Company, Inc., 1024-1025 Barnes & Jones, Incorporated, 1014 Bell and Gossett Company, 924-925 Bristol Company, The, 929 Brown Instrument Company, 930 Builders Iron Foundry, 965 Consolidated Ashcroft Hancock Co., Inc., 931 ..--Julien P. Friez & Sons, Inc., 1037 Illinois Testing Laboratories Inc., 933 Johnson Service Company, 1040 1041 Leeds & Northrup Company, 934 Minneapolis-Honeywell Regulator Company, 1044-1049 Powers Regulator Co., The, 1050 1051 Taylor Instrument Companies, 936 937 United States Gauge Co., 938 TRADE JOURNALS (See Pub iicatious) TRAPS, Bucket Armstrong Machine Works, 1008 1009 Crane Co., 868-869 C. A. Dunham Company, 1012 1013 ' Illinois Engineering Company, 1018-1019 Mueller Steam Specialty Co., Inc., 1023 Trane Company, The, 1027 Wright-Austin Co., 1031 TRAPS, Float Armstrong Machine Works, 1008 Crane Co., 868-869 C. A. Dunham Company, 1012 1013 William S. Haines & Company, 1020 * Hoffman Specialty Co., Inc., 1016 1017 Illinois Engineering Company, 1018-1019 Kieley & Mueller, Inc., 1021 Mueller Steam Specialty Co., Inc., 1023 Sarco Company, Inc., 1024-1025 Sterling Engineering Company, 1026 Trane Company, The, 1027 . Warren Webster & Company, 1028 1030 THERMOMETERS, Indicating Bristol Company, The, 929 .Brown Instrument Company, 930 Builders Iron Foundry, 965 ' Consolidated Ashcroft Hancock . Co., Inc., 931 Julien P. Friez & Sons, Inc., 1037 Illinois Testing Laboratories Inc.-, . 933 Johnson Service Company, 1040 1041 Leeds & Northrup Company, 934 1009 Crane Co., 868-869 C. A. Dunham Company, 1012 1013 Williams S. Haines & Company, 1020 Hoffman Specialty Co., Inc., 1016 1017 - Illinois Engineering Company, 1018-1019 ... Mueller Steam Specialty Co., Inc., 1023 . Sarco Company, Inci, 1024^-1025 TRAPS, Steam American District Steam Company, 897 . Armstrong Machine Works, 1008 1009 . Barnes & Jones, Incorporated, 1014 Crane Co., 868-869 Grinnell Company, .Inc., 919-921, 1015 William S. Haines & Company, 1020 Hoffman Specialty Co., Inc., 1016 1017 Numerals following Manufacturers' Names refer to pages In the Catalog Data Section 1077 1936American Society of Heating and Ventilating Engineers Guide, Illinois Engineering Company, 1018-1019 Kieley & Mueller, Inc., 1021 Mueller Steam Specialty Co., Inc., 1023 ,, Powers Regulator Co., The, 1050* 1051 Sarco Company, Inc., 1024-1025 Sterling Engineering Company, 1026 . Trane Company, The, 1027 Warren Webster & Company, 1028 TUBING, Copper Aerofin Corporation, 915-917- American Brass Company, The, 972-973 Bell and Gossett Company, 924-925 Chase Brass & Copper Co. Incor porated, 974-975, 999 Mueller Brass Co., 976-977 Revere Copper and Brass Incor porated, 979 Streamline Pipe and Fittings Co., 976-977 Savage Arms Corporation, 816 Servel, Inc., 817 Thermal Units Manufacturing . Company, 818 Trane Company, The, 1027 Unit Heater and Cooler Co., The, 913 Westinghouse Electric & Manu facturing Co., 819, 970 York Ice Machinery Corporation, 820 Young Radiator Company, 914 1030 Wright-Austin Co.. 1031 Wolverine Tube Company, 980 V-BELT DRIVES TUBING, Steel Carbondale Machine Corporation, TRAPS. Thermostatic Jones & Laughlin Steel Corpora 824. Barnes & Jones, Incorporated, 1014 C. A. Dunham Company, 1012 1013 Grinnell Company, Inc., 919-921, 1015 tion, 971 Republic Steel Corporation, 821 TURBINE BLOWERS (See Blowers, Turbine) VACUUM HEATING SYSTEMS (See Healing Systems, Vacuum) VALVES, Air William S. Haines & Company, 1020 Hoffman Specialty Co., Inc., 1016 1017 .. Illinois Engineering Company, 1018-1019 _ Powers Regulator Co.t The, 1050 1051 Sarco Company, Inc., 1024-1025 Sterling Engineering Company, 1026 ' Trane Company, The, 1027 Warren Webster & Company, 1028 1030 . TURBINES Coppus Engineering Corporation, 852 B. F. Sturtevant Co., 908 Westinghouse Electric & Manu facturing Co., 819, 970 L. J. Wing Mfg. Co., 906-907 UNDERGROUND PIPE CON DUITS (Sc* Conduits, Under ground Pipe) UNIT HEATERS (See Healers, Unit) American Radiator Company, 801, 861-865 Anderson Manufacturing Co., 1054 1055 Beaton & Cadwell Mfg. Company, The. 1010-1011 Bristol Company. The, 929 Burnham Boiler Corporation, 86(^ 867 . Carbondale Machine Corporation, 824 Crane Co., 868-869 Curtis Refrigerating Machine Com pany, Division of Curtis Manu facturing Company, 826 TRAPS, Vacuum UNIT VENTILATORS (See Armstrong Machine Works, 1008 Ventilators, Unit) 1009 Barnes & Jones, Incorporated, 1014 UNITS, Air Conditioning C. A. Dunham Company, 1012 Aeriet Air Conditioner Company, 1013 ' ^ 799 William S. Haines & Company, Airtemp Incorporated, 800 1020 . American Blower Corporation, 802 Hoffman Specialty Co., Inc., 1016 803 1017 Illinois Engineering Company, American Radiator Company, 801, 861-865 1018-1019 .,, . Baker Ice Machine Co., Inc., 823 Mueller Steam Specialty Co., Inc., Betz Unit Air Cooler Co., 804 1023 ,, Buckeye Blower Company, 922-923 Sterling Engineering Company, Buffalo Forge Company, 901 1026 Trane Company, The, 1027 Warren Webster & Company, 1028 1030 ^ Wright-Austin Co., 1031 Burnham Boiler Corporation, 866 867 E. K. Campbell Heating Co., 909 Canadian Sirocco Co., Ltd., 802-803 Carbondale Machine Corporation, 824 ' TUBES, Boiler . Carrier Engineering Corporation, Babcock & Wilcox Company, The, 877 ' Bigelow Company, The, 878 Jones & Laughlin Steel Corpora tion, 971 Republic Steel Corporation, 978 825 Clarage Fan Company, 805 Curtis Refrigerating Machine Com pany, Division Curtis Manu facturing Company, 826 Electro! Incorporated, 89r Fedders Manufacturing Co., 911 Frigidaire Corporation, 806-807' TUBES, Pitot (See Air Measuring General Electric Company, 838 and Recording Instruments) 839, 968-969 Detroit Lubricator Company, 1036 Dole Valve Company, The, 1053 C. A. Dunham Company, 1012 1013 . Foster Engineering Co., 1056 Hoffman Specialty Co., Inc., 1016 1017 . Jenkins Bros., 1057 New York Air Valve Corporation, 1058 _ Sterling Engineering Company, 1026 ,, Trane Company, The, 1027 Wright-Austin Co., 1031 VALVES, Angle, Globe and Cross American Radiator Company, 801, 861-865 Carbondale Machine Corporation, 824 . Consolidated Ashcroft Hancock Co., Inc., 931 Crane Co.. 868-869 Detroit Lubricator Company, 1036 Frick Company (Incorporated), 827 Grinnell Company, Inc., 919-921, 1015 . Jenkins Bros., 1057 York Ice Machinery Corporation, 820 * TUBING, Aluminum Wolverine Tube Company, 980 TUBING, Brass American Brass Company, The, 972-973 Chase Brass & Copper Co. Incor porated, 974-975, 999 Mueller Brass Co., 976-977 Revere Copper and Brass Incor porated, 979 . Streamline Pipe and .Fittings' Co., 976:977 .- Wolverine Tube Company, 980 Gilbert & Barker Mfg. Co.-, 840-842 Grinnell Company, Inc, 919-921, VALVES, Automatic 1015 .. Anderson Manufacturing Co., 1054 Henry Furnace & Foundry Co., 1055- , 843. 896 Barber-Colman Company, 1034 Ilg Electric Ventilating Company, 1035 903 Beaton & Cadwell Mfg. Company, Kelvinator Corporation, 808-811 The, 1010-1011 McQuay, Incorporated, 812 ' Bristol Company, The, 929 Meyer Furnace Company, The, 846 Crane Co., 868-869 Modine Manufacturing Co., 912 Detroit Lubricator Company, 1036 L. J. Mueller Furnace Co., 844-845 Foster Engineering Co., 1056 John J. Nesbitt, Inc., 922-923 Julien P. Friez & Sons, .Inc., 1037 Niagara Blower Company, 814-815 General Controls, 1042 Norge Division, Borg-Warner Cor Minneapolis-Honeywell Regulator poration, 830, 847, 892 Company, 1044-1049 . Please mention THE GUIDE 1936 when writing to Advertisers 1078 Index to Modern Equipment New York Air Valve Corporation.. Illinois Engineering Company, 1058 1018-1019 Sterling Engineering .Company, Kieley & Mueller, Inc., 1021' 1026 McDonnell & Miller, 858-859 Trane Company, The, 1027 Mueller Steam Specialty Co., Inc., 1023 . VALVES, Back Pressure Sterling Engineering Company, Crane Co., 868-869 1026 Fedders Manufacturing Co., 911 Trane Company, The, 1027 Foster Engineering Co., 1056 York Ice Machinery Corporation, Illinois Engineering Company, 820 VALVES, Pump Carbondale Machine Corporation. 824 Crane Co., 868-869 - Jenkins Bros., 1057 - John H. McGowan Company, The. 997 Trane Company, The, 1027 , VALVES, Radiator , 1018-1019 American Radiator Company. 801, Jenkins Bros., 1057 VALVES, Flow Control . 861-865 Mueller Steam Specialty Co., Inc., 1023 Taylor Instrument Companies, 936 937 ' York Ice Machinery Corporation, 820 Consolidated Ashcroft Hancock Barnes & Jones. Incorporated, 1014 Co., Inc., 931 Bell and Gossett Company, 924-925 Foster Engineering Co., 1056 . Burnham Boiler Corporation. 866 General Controls, 1042 867 1 General Electric Company, 838 Crane Co., 868-869 839, 968-969 Detroit Lubricator Company, 1036 Minneapolis-Honeywell Regulator C. A. Dunham Company. 1012 VALVES, Balanced Company, 1044-1049 1013 Crane Co., 868-869 Mueller Steam Specialty Co., Inc., Fulton Sylphon Co., 1038-1039 Foster Engineering Co., 1056 Illinois Engineering Company, 1023 Grinnell Company. Inc., 919-921, Powers Regulator Co., The., 1050 1015 1018-1019 1051 ? William S. Haines & Co., 1020 Jenkins Bros., 1057 Mueller Steam Specialty Co., Inc., 1023 Sterling Engineering Company. 1026 Taylor Instrument Companies, 936 Hoffman Specialty Co., Inc., 1016 1017 . Jenkins Bros., 1057 * 937 National Radiator Corporation, VALVES. Blow-off Consolidated Ashcroft Co., Inc., 931 Crane Co., 868-869 Jenkins Bros., 1057 VALVES, By-pass Consolidated Ashcroft Co., Inc., 931 Crane Co., 868-869 Jenkins Bros., 1057 . - H. A. Thrush & Co., 926-927 Hancock VALVES, Gate American Brass Company, The. 972-973 American Radiator Company, 801, 861-865 Hancock Consolidated Ashcroft Co., Inc., 931 Hancock . Crane Co., 868-869 Detroit Lubricator Company, 1036 Jenkins Bros., 1057 . . 870-871 New York Air Valve Corporation. 1058 . Sarco Company, Inc., 1024-1025 Sterling Engineering Company, 1026 Trane Company, The, 1027 Warren Webster & Company, 1028 1030 VALVES, Radiator, Electric Motor Operated . VALVES, Check VALVES, Hydraulic Barber-Colman Company, 1034 1035 * Consolidated Ashcroft Hancock Consolidated Ashcroft Hancock Detroit Lubricator Company, 1036 Co., Inc., 931 Co.. Inc., 931 Julien P. Friez & Sons. Inc., 1037 Crane Co., 868-869 Crane Co.. 868-869 Fulton Sylphon Co., 1038-1039 Foster Engineering Co., 1056 Foster Engineering Co., 2056 General Electric Company, 838 Frick Company (Incorporated), 827 Jenkins Bros., 1057 Grinnell Company, Inc., 919-921. 839, 968-969 Jenkins Bros., 1057 1015 Illinois Engineering Company. VALVES, Magnetic . Minneapolis-Honeywell Regulator Company, 1044-1049 1018-1019 Armstrong Machine Works, 1008 Jenkins Bros., 1057 York Ice Machinery Corporation. 820 1009 Barber-Colman 1035 Company, , 1034 VALVES, Radiator, Orifice American District Steam Company, Detroit Lubricator Company, 1036 897 VALVES, Diaphragm Powers Regulator Co., The, 1050 1051 " VALVES, Expansion Crane Co.. 868-869 _ Detroit Lubricator Company, 1036 Frick Company (Incorporated). 827 Julien P. Friez & Sons, Inc., 1037 General Controls, 1042 General Electric Company, 838 839,968-969 . Minneapolis-Honeywell . Regulator Company, 1044-1049 Barnes & Jones, Incorporated, 1014 Bell and Gossett Company, 924-925 Detroit Lubricator Company, 1036 C. A. Dunham Company, -1012 1013 . Grinnell Company, Inc., 919-921, 1015 . William S. Haines & Co., 1020 Fedders Manufacturing Co., 911 Foster Engineering Co.,1056 VALVES, Mixing, Thermostatic Hoffman Specialty Co., Inc., 1016 1017 Frick Company (Incorporated),.827 Powers Regulator Co., The, 1050- New York Air Valve Corporation, York Ice Machinery Corporation, 1051 1 1058 820 Sarco Company, Inc., 1024-1025 VALVES, Float Anderson Manufacturing Co., 1054 1055 . vCarbondale Machine Corporation. 824 Crane Co., 868-869 Detroit Lubricator Company, 1036 Dole Valve Company, The. 1053 C. A. Dunham "Company, 1012 1013 Fedders Manufacturing Co., 911 Foster Engineering Co., 1056 Frick Company (Incorporated), 827 General Electric Company. 838 839, 968-969 VALVES, Non-Return - American Brass Company, The, 972-973 Consolidated Ashcroft Hancock Co., Inc., 931 Crane Co., 868-869 -F--e-d--d- ev,r,,s.,Manufacturing Co.; 911 Foster Engineering Co., 1056 'F*-ri-ck Company "(Incorporat-ed ), 827 Illinois Engineering Company, 1018-1019 , Jenkins Bros., 1057 ` Kieley & Mueller, Inc., 1021 VALVES, Pressure Reducing (See Regulators, Pressure) Sterling Engineering Company, 1026 Trane Company, The, 1027 Warren Webster & Company, 1028 1030 VALVES, Radiator, Pneumatic Diaphragm Bell and Gossett Company, 924-925 Johnson Service Company. 1040 1041 - ` National Regulator Co., 1052 Powers Regulator Co.. The. 1050 1051 Taylor Instrument Companies. 936-' 937 . Numerals following Manufacturers' Names refer to pages in the Catalog Data Section 1079 American Society of Heating and Ventilating Engineers Guide, 1936 VALVES, Relief American Radiator Company, 801, 861-865 Baker Ice Machine Co., Inc., 823 Beaton & Cadwell Mfg. Company, The, 1010-1011 Bell and Gossett Company, 924-925 Consolidated Ashcroft Hancock Co., Inc., 931 Crane Co., 868-869 Foster Engineering Co., 1056 Illinois Engineering Company, 1018-1019 J. E. Lonergan Co., 1022 Mueller Steam Specialty Co., Inc., 1023 New York Air Valve Corporation, 1058 Trane Company, The, 1027 H. A. Thrush & Co., 926-927 York Ice Machinery Corporation, 820 VALVES, Safety American Radiator Company, 801, 861-865 Baker Ice Machine Co., Inc., 823 Beaton & Cadwell Mfg. Company, The, 1010-1011 Consolidated Ashcroft Hancock Co., Inc.. 931 Crane Co.,- 868-869 Detroit Lubricator Company, 1036 Frick Company (Incorporated), 827 Jenkins Bros., 1057 J. E. Lonergan Co., 1022 New York Air Valve Corporation, 1058 VALVES, Water Regulating Beaton & Cadwell Mfg. Company, The, 1010-1011 Bell and Gossett Company,.924-925 Crane Co., 868-869 Detroit Lubricator Company, 1036 Foster Engineering Co., 1056 Mueller Steam Specialty Co., Inc., 1023 Powers Regulator Co., The, 1050 1051 - H. A. Thrush & Co.. 926-927 York Ice Machinery Corporation, 820 . VAPOR HEATING SYSTEMS (See Heating Systems, Vapor) VENTILATORS, Floor and Wall American Blower Corporation, 802 803 Auer Register Co., The, 1001 Barber-Colman Company, 1034 1035 Canadian Sirocco Co., Ltd., 802-803 Carrier Engineering Corporation, 825 Hart & Cooley Manufacturing Co., 1002-1003 Independent Register & Mfg. Co., 1006 L. J. Mueller Furnace Co., 844-845 Tuttle & Bailey, Inc., 1004-1005 Waterloo Register Company, The, 1007 Young Ventilating Company, The, 849 . WARM AIR FURNACES (See Furnaces, Warm Air) WARM AIR HEATING SYS TEMS (See Heating Systems, Furnace) WATER CONDITIONING American Blower Corporation, 802 803 Aquatic Chemical & Metallurgical Engineers, 860 Canadian Sirocco Co., Ltd., 802-803 Ferro-Nil Corporation, 1060 Vinco Company, Inc., The, 857 WATER COOLING Baker Ice Machine Co., Inc., 823 Carbondale Machine Corporation, 824 Carrier Engineering Corporation, 825 Curtis Refrigerating Machine Com pany, Division of Curtis Manu facturing Company, 826 Frick Company (Incorporated), 827 Ingersoll-Rand Company, 828-829 Norge Division, Borg-Wamer Cor poration, 830, 847, 892 Universal Cooler Corporation, 831 Vilter Manufacturing Company, The. 832 Wittenmeier Machinery Company, 833 WATER FEEDERS (See Feeders, Water) VALVES, Solenoid Anderson Manufacturing Co., 1054 1055 Barber-Colman Company, 1034 1035 Detroit Lubricator Company, 1036 Foster Engineering Co., 1056 Frick Company (Incorporated), 827 Julien P. Friez & Sons, Inc., 1037 'General Controls, 1042 . General Electric Company, 838 839, 968-969 . Trane Company, The, 1027 VALVES, Stop and Check (See Valves, Non-Return) VALVES, Thermostatic Barber-Colman. Company, 1034 1035 Detroit Lubricator Company, 1036 C. A. Dunham Company, 1012 1013 - Fedders Manufacturing Co., 911 Foster Engineering Co., 1056 Fulton Sylphon Co., 1038-1039 General Electric Company, 838 839, 968-969 Grinneli Company, Inc., 919-921, 1015 . . Illinois Engineering Company, 1018-1019 . Minneapolis-Honeywell Regulator Company, 1044-1049 > New York Air Valve Corporation, 1058 . Powers Regulator Co., The, 1050 1051 Sarco Company, Inc., 1024-1025 Sterling Engineering Company, 1026 Taylor Instrument Companies, 936 937 Trane Company, The, 1027 Warren Webster & Company, 1028 1030 VENTILATORS, Mushroom American Blower Corporation, 802 803 Canadian Sirocco Co., Ltd., 802-803 Clarage Fan Company, 805 L. J. Mueller Furnace Co., 844-845 Tuttle & Bailey, Inc., 1004-1005 VENTILATORS, Roof Air Controls, Inc., 834 Burt Mfg. Co., The, 1059 General Electric Company, 838 839, 968-969 Ilg Electric Ventilating Company, 903 Johns-Manville, 950-951 B. F. Sturtevant Co., 908 VENTILATORS, Unit Aeriet Air Conditioner Company, 799 American Blower Corporation, 802 803 . Buckeye Blower Company, 922-923 Buffalo Forge Company, 901 E. K. Campbell Heating Co., 909 Canadian Sirocco Co., Ltd., 802-803 Ilg Electric Ventilating Company, 903 v John J. Nesbitt, Inc., 922-923 Savage Arms Corporation, 816 B. F. Sturtevant Co., 908 Trane Company, The, 1027 Young Radiator Company, 914 VENTILATORS, Window Aeriet Air Conditioner Co., 799 American Air Filter Company Inc., 850-851 Ilg Electric Ventilating Company, 903 Savage Arms Corporation, 816 Staynew Filter Corporation, 856 WATER HEATERS (See Heaters, Hoi Water Service) WEATHER INSTRUMENTS, Indicating and Recording Bristol Company, The, 929 Brown Instrument Company, 930 Consolidated Ashcroft Hancock Co., Inc., 931 Julien P. Friez & Sons, Inc., 1037 Hays Corporation, 932 Leeds & Northrup Company, 934 Minneapolis-Honeywell Regulator Company, 1044-1049 Palmer Company, The, 935 Taylor Instrument Companies, 936 937 . WELDING AND CUTTING APPARATUS Westinghouse Electric & Manu facturing Co., 819, 970 WELDING FITTINGS (See Fit tings, Welding) , WELDING ROD Revere Copper and Brass Incor porated, 979 WHEELS, Blower Air Controls, Inc., 834 American Blower Corporation, 802 803 Bayley Blower Company, 900 Buffalo Forge Company, 901 Canadian Sirocco Co., Ltd., 802-803 Clarage Fan Company, 805 .' Henry Furnace & Foundry Co., 843, 896 L. J. Mueller Furnace Co., 844-845 Niagara Blower Company, 814-815 B. F. Sturtevant Co., 908 Torrington Mfg- Co., The, 904-905 Please mention THE GUIDE 1936 when writing to Advertisers 1080 Roll of Membership American society of HEATING and VENTILATING ENGINEERS 1936 Contains Lists of Members Arranged Alphabetically and Geographically, also Lists of Officers and Committees, Past Officers and Local Chapter Officers Corrected to January 1, 1936 Published at the Headquarters of the Society 51 Madison Avenue, New York, N. Y. Officers and Council American Society of Heating and Ventilating Engineers 51 Madison Ave., New York, N. Y. 1935-36 President...................... First Vice-President__ Second Vice-President. Treasurer_______ ____ Secretary...................... .........-John Howatt ........._G. L. Larson .......... D. S. Boyden ---------- A. J. Offner .A. V. Hutchinson une year R. H. Carpenter J. D. Cassell C. V. Haynes F. C. McIntosh L. W. Moon Council John Howatt, Chairman G. L. Larson, Vice-Chairman 1 wo Years M. C. Beuan E. H. Gurney O. W. On W_A. Russell ' Three Years Albert Buenger F. E. Giesecke J. F. McIntire W. E. Stark Committees of the Council Executive:- C. V. Haynes, Chairman; L. W. Moon, M. C. Beman. Finance: E. H. Gurney, Chairman; J. F. McIntire, D. S. Boyden. Meetings: Albert Buenger, Chairman; F. E. Giesecke, O. W. Ott.' Membership: F. C. McIntosh, Chairman; W. A. Russell, J. D. Cassell. . Advisory Council C. V. Haynes, Chairman; W. H. Carrier, Homer Addams, R. P. Bolton, S. E. Dibble, W. H. Driscoll, H. P. Gant, John F. Hale, L. A. Harding, H. M. Hart, E. Vernon Hill, J. D. Hoffman, W. T. Jones, D. D. Kimball, S. R. Lewis,- Thornton Lewis, J. I. Lyle, J. R. McColl, D. M. Quay, C. L. Riley, F. B. Rowley, F. R. Still and A. C. Willard. . Cooperating Committees A.S.H.V.E. Representative on National Research Council; Prof. F. E. Giesecke (2 years). 3 Special Committees Committee on Admission and Advancement: J. G. Eadie, Chairman (one year); E. N. ' Sanbern (too years), and E. J. Ritchie (three years). Publication Committee: W. M. Sawdon, Chairman (one year); M. C. Beman (too years), and A. I. Brown (three years). Committee on Constitution and By-Laws: W. T. Jones, Chairman; R. H. Carpenter and J. F. Hale. Guide Publication Committee: G. L. Larson, Chairman; S. H. Downs, E. A. Jones, W. L. Flasher, E. N. McDonnell, W. W. Timmis and J. H. Walker. Committee on Ventilation Standards: W. H. Driscoll, Chairman; J. J. Aeberly, W. H, Carrier, Thomas Chester, L. A. Harding, H. M. Hart, E. V. Hill, J. R. McColl, W. A. Rowe, Perry West, A. C. Willard and C.-E. A. Winslow. Committee on Standardization of Codes: S. R. Lewis, Chairman; P. D. Close and L. A. Harding. . F. Paul Anderson Medal Award Committee: G. L. Larson, Chairman; H. P. Gant, L. A. Harding, S. R. Lewis and W. E. Stark. Exposition Advisory Committee: John Howatt, Chairman; J. M. Frank, F. H. Gaylord, R. E. Hattis, A. B. Martin, E. M. Mittendorf and J. R. Vernon. Chapter . Cleveland Cincinnati Illinois Kansas City Massachusetts Michigan Western Michigan Minnesota New York Western New York Ontario Pacific Northwest Philadelphia Pittsburgh St. Louis Wisconsin ' Committees--1935 Nominating Committee for 1935 Representative C. F. Eveleti, H. E. Sproull J. J. Aeberly . L. R. Chase W. E. Barnes W. G. Boales . K. L. Ziesse . ' M. S. Wunderlich W. W. Timmis ' J. J. Yager M. F. Thomas M. J. Hauan H. H.. Erickson F, C. McIntosh R. J. Tenkonohy E. A. Jones Alternate F. A. Kitchen C. E. Hust J. J. Hayes . W. A. Russell W. J. Hajek H. E. Paetz J. H. Van Alsburg R. E. Backstrom V. J. Cucci D. J. Mahoney H. H. Angus . M. N. Musgrave M. F. Blankin H. L. Moore . J. W. Cooper Ernest Szekely. 4 One Year Albert Buenger S. H. Downs H. N. Kitchell H. R. Linn Perry West Committee on Research A. P. Kratz, Chairman J. H. Walker, Vice-Chairman . Dr. A. C. Willard, Technical Adviser. F. C. Houghten, Director O. P. Hood, Ex-Officio Member Two Years C. A. Booth E. K. Campbell John Howatt A. J. Nesbitt J. H. Walker Three Years ' C. A. Dunham W. L. Fleisher Elliott Harrington A. P. Kratz H. C. Murphy Executive Committee A. Pi Kratz, Chairman Albert Buenger J. H. Walker Finance Committee W. L. Fleisher, Chairman E. C. Evans A. J. Nesbitt Elliott Harrington L. B. Miller Air Conditions and Their Relation to Living Comfort: C. P. Yaglou, Chairman; J. J. Aeberly, W. L. Fleisher, R. R. Sayers and C.-E. A. Winslow. Air Conditioning in the Treatment of Diseases: E. V. Hill, Chairman; N. D. Adams, J. J. Aeberly, Margaret Ingels, H. R. Linn and E. L. Stammer. Atmospheric Dust and Air Cleaning Devices (Including Dust and Smoke): H. C. Murphy, Chairman; J. J. Bloomfield, M. I. Dorfan, Philip Drinker, Leonard Greenburg, S. R. Lewis, F. B. Rowley, D. C. Simpson and W: O. Vedder. Corrosion: J. H. Walker, Chairman; E. L. Chappell, W. H. Driscoll, C. A. Dunham, L. B. Miller, R. R. Seeber and C. M. Sterne. - Direct and Indirect Radiation with Gravity Air Circulation: H. F. Hutzel, Chairman; M. K. Fahnestock, H. R. Linn, J. P. Magos, J. W. McElgin, J. F. Mclntire, T. A. Novotney and R. N. Trane. Gas Heating Equipment: W. E. Stark, Chairman; R. M. Conner, C. A. Dunham,.Robert Harper, E. A. Jones, Thomson King, J. F. Mclntire, E. L. Tomquist and H. L. Whitelaw. Heat Requirements of Buildings: D. S. Boyden, Chairman; P. D. Close, W. H. Driscoll, ; H. M. Hart, P. E. Holcombe, V. W. Hunter, G. L. Larson, H. H. Mather, E. C. Rack, F. B. Rowley, R. J. J. Tennant and J. H. Walker. Heat Transfer of Finned Tubes with Forced Air Circulation: F. B. Rowley, Chairman; S. H. Downs, H. F. Hutzel, E. J. Lindseth, R. H. Norris, W. E. Stark and G. L. Tuve. Minimum Temperature and Method of Introduction of Cooling Air in Classrooms:' Perry West, Chairman; J. D. Cassell, S: R-. Lewis, J. R. McColl, A. J. Nesbitt, G. E. Otis and C.-E. A. Winslow. Refrigeration in Relation to Air Treatment: M. K. Fahnestock, Chairman; E. A. Brandt, John Everetts, Jr., Elliott Harrington, E. D. Milener, K. W. Miller, E. B. Newill, F. G. Sedgwick and J. H. Walker. .. Sound in Relation to Healing and Ventilation: V. O. Knudsen, Chairman; C. M. Ashley, C. A. Booth, F. C.'McIntosh, R. F. Norris, J. S. Parkinson, C. H. Randolph, J. P: Reis and G. T. Stanton. Ventilation of Garages and Bus Tetoninqls: E. K. Campbell, Chairman; S. H. Downs,. T. M. Dugan, E. C. Evans, F. H. Hecht, H. L. Moore and A. H. Sluss. Effect of Entering Temperature and Velocity on the Temperature and Distribution of Air Within an Enclosure: C. H. Randolph, Chairman; E. H. Baars, J. S. Jung, F. A. Kartak, J. E. Schoen, Ernest Szekely and J. H. Volk. ' Comfort Standards for Summer Cooling: W. L. Fleisher, Chairman; A. E. Beals, E. R. Bichowsky, Elliott Harrington, E. V. Hill and C. P. Yaglou. Frictional Resistance to. Flow of Air in Small Ducts and Fittings: J. H. Van Alsburg, Chairman; C. A. Booth, S. H. Downs, L. B. Miller and L. E. Smith. Corrosion in Air Conditioning Equipment: A. E. Stacey, Chairman; M. S. Kice, F. N. Speller, C. M. Sterne, R. T. Thornton and J. H. Walker. 5 Officers of Local Chapters 1935-36 Cleveland Headquarters, Cleveland, Ohio Meets: Second Thursday in Month President, G. L. Tuve Case School of Applied Science Secretary, Philip Cohen 407 E. Ohio Gas Bldg. - . Western New York Headquarters. Buffalo Meets: Second Monday in Month President, W. E. Voisinbt 250 Delaware Avenue Secretary, J. J. Landers 303 Crosby Bldg. Cincinnati Headquarters. Cincinnati. Ohio Meets: Second Tuesday in Month President, G. B. Houliston 704 Race Street Secretary, I. B. Helburn 610 Chamber of Commerce Bldg. Illinois Headquarters, Chicago Meets: Second Monday in Month President, J. H. Milliken 20 N. Wacker Drive Secretary, L. S. Ribs 060 East 58th Street Kansas City Headquarters, Kansas City, Mo. Meets: Second Monday in Month President, C. A. Weiss 1811 Troost Avenue Secretary, G. L. Bliss 1410 Waldheim Bldg. Manitoba Headquarters, Winnipeg, Man., Canada Meets: Fourth Txtesday in Month President, J. B. Steele 184 Waterloo Street Secretary, C. H. Turland 325 Centennial Street Massachusetts Headquarters, Boston Meets: Second Monday in Month President, W. A. McPherson 86 Dwinnell Street, West Roxbuiy. Mass. Secretary, G. B. Gbrrish 1 Overlook Road, Melrose, Mass. t Michigan ' Headquarters, Detroit Meets: First Monday after the 10th of the Month President, A. C. Wallich ' 1667 Burlingame Avenue Secretary, W. F. Arnoldy 2847 Grand River Avenue Oklahoma City President, F. X. Loefflbr 710 N. Hudson Street Secretary, H. J. Levbrancb 1838 Northwest 11th Street ` Ontario Headquarters, Toronto, Canada Meets: First Monday Every Other Month President, M. W. Shears 39 Sylvan Avenue Secretary, H. R. Roth 57 Bloor Street, W. , Pacific Northwest Headquarters. Seattle, Wash. Meets: Second Tuesday in Month President, Lincoln Bouillon 4186-42nd Avenue. N.E. Secretary, D. C. Griffin Orpheum Bldg. Philadelphia Headquarters, Philadelphia, Pa Meets: Second Thursday in Month President, J. H. Hucker 1700 Walnut Street Secretary, H. H. Erickson 804 Architects Bldg. . Pittsburgh Headquarters, Pittsburgh, Pa. Meets: Second Monday in Month President, R. J. J. Tennant 435 Sixth Avenue Secretary, T. F. Rockwell Carnegie Institute of Technology St. Louis ' Headquarters, St. Louis, Mo. Meets: First Wednesday in Month President, C. R. Davis 2328 Locust Street Secretary, R. J. Tenkonohy 3650 Shaw Boulevard Western Michigan Headquarters, Grand Rapids Meets: Second Monday in Month President, P. O. Wierbnga 49 Coldbrook Street, N.E. Secretary, J. J. Troske 236 Winter Avenue, N.W. . Southern California Headquarters, Los Angeles Meets: Second Tuesday in Month President, Leo.Hungbrford 524 Loew's State Bldg. Secretary, H. M. Hendrickson 5051 Santa Fe Avenue Minnesota ' Headquarters, Minneapolis Meets: Second Monday in Month President, C. E. Gausman 2360 Chilcombe, St. Paul, Minn.' Secretary, R. E. Backstrom . 643 S. Snelling Avenue, St. Paul, Minn. New York Headquarters, New York Meets: Third Monday in Month President, W. W. Timmis 40 West 40th Street Secretary, T. W. Reynolds 100 Pinecrest Drive, Hastings-on-Hudson, N. Y. , Washington, D. C. Headquarters, Washington, D. C. Meets: Second Wednesday in Month President, W. A. Danielson . 3812 Fulton Street, N.W, Secretary, M. D. Kiczalbs 3000 Connecticut Avenue, N.W. Wisconsin . . Headquarters, Milwaukee Meets: Third Monday in Month President, C. H. Randolph 1925 N. Prospect Avenue Secretary, R. G. Koch . 626 E. Wisconsin Avenue 6 Roll of Membership American Society of Heating and Ventilating Engineers 1936 HONORARY MEMBERS WM. j. (1915;, New York, N. Y. (Deceased May 7, 1924.) ILLINGS, DR. J. S. (1896), New York, N. Y. (Deceased March 10, 1913.) GORMLY, JOHN (Charter Member), Norristown, Pa. (Deceased January 31, 1929.) NEWTON, C. W. (Charter Member), Baltimore, Md. (Deceased August 6, 1920.) HOOD, O. P. (1929), Washington, D. C. JELLETT, STEWART A. (Charter Member), (Presidential Member), Philadelphia, Pa. (Deceased April 5, 1935.) LIST OF MEMBERS Arranged Alphabetically (Asterisk indicates authorship of papers) A ABRAMS, Abraham (if 1927; J 1924), Pres., Abbey Htg. Co., Inc., 81 Centre Ave., and (for mail), 100 Clove Rd., New Rochelle, N. Y. ACHESON, Albert R. (M 1919), Consulting Engr. (for mail), 501 Eckel Theatre Bldg., and 852 Ostrom Ave., Syracuse, N. Y. ADAMS, Benjamin (M 1919), Dist. Mgr. (for mail), American Blower Corp., 781 Broad St.. Station Bldg. 1617 Pennsylvania Blvd., and 3006 W. Coulter St., Queen Lane Manor, Philadelphia, Pn. ADAMS, Charles W. (if 1920). Salesman. U. S. Radiator Corp., 1405 West 11th St., Kansas City, Mo. ADAMS, Eugene I. (M 1934), Plant Engr., Michigan State College, and (for mail), 115 S. Pine, Lansing, Mich. ADAMS, Harold E. (if 1930), Chief Engr. (for mail), Nash Engineering Co., South Norwalk, and Merrill Heights, Norwalk, Conn. ADAMS, Neil D. (M 1929; A 1925; J 1922), Supt., Franklin Htg. Station (for mail), 220 Second Ave. S.W., and 836 Eighth Ave. S.W., Rochester, Minn. ADDAMS, Homer (iCharter Member; Life Member), (Presidential Member), (Pres., 1924; 1st VicePres., 1923; Treas., 1915-1922; Council, 1915 1925), Pres.. Kewanee Boiler Co., Inc., and Fitzgibbons Boiler Co., Inc., 570 Seventh Ave., New York, N. Y. ADLAM, T. Napier (if 1932). Vice-Pres. and Gen. Mgr., Sarco Mfg. Co., 183 Madison Ave., New York, N. Y., and (for mail), 64 Wellington Ave., West Orange, N. J. ADLER, Alphonse A.* (if 1921), Consulting Engr., 35 Stewart Ave., Arlington, N. J. AEBERLY, John J * (M 1928). Chief of Div. of Htg., Vtg. and Ind. Sanitation, Chicago Board of Health, 707 City Hall, and (for mail), 6225 N. Newcastle Ave., Norwood Park P. O., Chicago, 111. AHEARN, William J. (M 1929), Htg. and Vtg. Engr., 21 Lake Road., Cochituate, Mass. AHLBERG, Henry B. (J 1933), Engr., Anderson Mfg. Co., 190 Albany St., Cambridge, and (for mail). 60 Rockingham Ave., Malden. Mass. AHLFF, Albert A. (if 1923; A 1918), Chase Brass & Copper Co., and (for mail), 805 Cook St., Waterbury, Conn. . AIKEN, Jack F. (S 1935), 312 Walnut S.E., Minneapolis, Minn. A1TKEN, James (A 1935), Supt. (for mail), Anlhes Foundry, Ltd., and 923 Palmersron Ave., Winnipeg, Man., Canada. AKERS, George W. (if 1929), Secy-Treas. (for mail), George W. Akers Co., 2847. Grand River Ave., Detroit, and 424 Willitts, Birmingham, Mich. ALEXANDER, Samuel W. (if 1935), Mgr. Htg. Div., James Morrison Brass Co., 276 King St. wT, and (for mail), 124 Kingsmount Park Road, Toronto, Ont., Canada. ALFAGEME, Braullo (if 1935), Engr. Mgr., B Alfageme AJmagro 1, Madrid, Spain. ALFSEN, Nikolai Qf 1933), Civil Engr., Alfsen & Gunderson, Oslo P. O. Box 676, and (for mail). Shabekk near Oslo. Norway. - ALGREN, Axel B.* (M 1930), Asst. Prof. Mech. Engrg., University of Minnesota Exp. Engrg. Lab., and (for mail), 5109-17th Ave. S., Minne apolis, Minn. ALLAN, Norman J. (J 1934), Asst, to Pres.. Kansas City Pump Co., 1314 west 11th St., and (for mail), 3661 Madison Ave., Kansan City, Mo. ALLMEN, Norman S. (S 1934), 8420 Lake Ave., Cleveland, Ohio. ALLSOP, Rowland P. (J 1934). Engr. (for mail). Mathers & Haldenby, Archts., 96 Bloor St. W.. and 89 Neville Park Blvd., Toronto, Ont., Canada. - ALT, Harold L.* (if 1913), Bldg. Equip. Engr Gibbs & Hill, Penn Station. New York, N. Y., and (for mail), 18-C Kearny St., Newark, N. J. 7 American Society of Heating and Ventilating Engineers Guide, 1936 AMES, Charles F. (A 1928), Vice-Pres. and Sales Mgr., Ames Pump Co., Inc., 30 Church St., and' (for mail). Hotel Walton, 104 West 70th St., New York, N. Y. AMMERMAN, Charles R. (Jf 1916). Consulting Engr. (for mail), 772-4 Century Bldg., and 3908. Guilford Ave., Indianapolis. Ind. ANDEREGG, R. H. (Jf 1920), Vice-Pres., The Trane Co., and (for mail), 324 North 24th St., LaCrosse, Wis. ANDERSON, C. S. (M 1920). Mgr. (for mail). American Blower Corp., 429 Shell Bldg., 1008 W. Sixth St., and 4267 Holly Knoll Drive., Los Angeles, Calif. - ANDERSON, David B. (S 1933), Engrg. Dept., Wood Conversion Co., W-1981 First National Bank, and (for mail), 770 Holly Ave., St. Paul, Minn. ANDERSON, Lowell B. (S 1935), Illinois Steel Co., 89th and Strand, and (for mail), 6117 Eberhart Ave., Chicago, III. ' ANDERSON, Sigurd H. (S 1935), 3921 Blooming ton Ave., Minneapolis, Minn. ANDES, William (A 1934), Secy-Treas., The Andico Co., 565 Stones Levee, and (for mail), 3947 West 162nd St., Cleveland, Ohio. . ATHERTON, G. R. (Jf 1930), Air Cond. Div., American Radiator Co., 40 west 40th St., New York, N. Y. ATKINS, Thomas J. (Jf 1931). Sales Engr., Carrier Engrg. Corp., 12 South 12th St., Phila delphia, and (for mail), 119 Kenilworth Road, Merion, Pa. ATKINSON, Kenneth B. (7 1930), Eastern Field Mgr., Van Kannei Revolving Door Co., 101 Park Ave., New York, N. Y., and (for mail), Elizabeth-Carteret Hotel, Elizabeth, N. J. AUGHENBAUGH, Harry E. (Jf 1935), Br. Mgr., York Ice Machinery Corp., 1238-46 North 44th St., Philadelphia, and (for mail), 7105 Penarth Ave., Upper Darby, Pa. AVERY, Lester T. (Jf 1934), Pres, (for mail). Avery Engrg. Co., 2341 Carnegie Ave., Cleve land, and 21149 Colby Road, Shaker Heights, Ohio. AXEMAN, James E. (Jf 1932; A 1931; 7 1925), Branch Mgr. (for mail), Spencer Heater Co., 1205 Court Square Bldg., and 908 Old Oak Road. Stoneleigh, Baltimore, Md. AYERS, Earl H. (7 1935), Supt. (for mail), D. W. Hickey & Co., 1631 University Ave., and 543 S. Warwick Ave., St. Paul, Minn. ANDREWS, George H. (A 1934), Partner, Frank P. Andrews & Son, ZM Weshanock Ave., and (for mail), 213 Meyer Ave., New Castle, Pa. ANGUS, Harry H.* (Jf 1918), (Council, 1927 1929), Consulting Engr., 1221 Bay St., and (for mail), 34 Farnham Ave., Toronto, Ont., Canada., ANTHES, Lawrence L. (A 1935), Pres., Imperial Iron Corp., Ltd., 30 Jefferson Ave., and (for mail), Anthes Foundry, Ltd., 454 Jefferson Ave., and 119 Dowling Ave., Toronto, Ont., Canada. APT, Sanford R. (Jf 1935), Mech. Engr., U. S. Government, 1031 Navy Bldg., and (for mail), 483l-36th St. N.W., Washington, D. C. B BACHLER, Leonard J. (Jf 1918), 304 East 41st St., New York, N. Y. BACKSTROM, Russell E* (A 1931; 7 1928), (for mail). Wood Conversion Co., E-808 First National Bank Bldg., and 543 S. Snelling Ave., St. Paul, Minn. BACKUS, Theodore H, L. (Jf 1916), Htg. and Vtg. (for mail), 200-208 Hill Sl, and 1018 Vaughn St., Ann Arbor, Mich. BADGETT, W. Howard* (7 1932). Research Asst., Texas Engrg. Exp. Station, A. & ,M. ARCHER, David M. (Jf 1934), Sales Repr. (for mail), Sarco Co., Inc., 143 Federal St., Boston, and 10 Thurlow St., W. Roxbury, Mass. ARENBERG, MUton K. (A 1920)/Dist. Mgr. (for mail), Ilg Electric Vtg. Co., 182 N. LaSalle St., Chicago, and 1033 S. Linden Ave., Highland Park. 111. ARGUE, Edgar J. (A 1935), Salesman, Lennox Furnace Co. of Canada, Ltd. (for mail), Anthes . Foundry, Ltd., and Ste. 23 Estelle Apts., Winni College of Texas, College Station, Texas. BAHNSON, Frederick F* (M 1917), Vice-Pres. and Chief Engr. (for mail). The Bahnson Co., 1001 S. Marshall St., Pres., Southern Steel Stampings, Inc., P. O. Box 1942, and 28 Cascade Ave., Winston Salem, N. C. BAILEY, Edward P. Jr. (Af 1925), Consultant Mayfield Road at Lee Blvd, and (for mail), 2475 Lee Blvd., Cleveland, Ohio. BAILEY, W. Mumford (Jf 1930), Managing peg, Man., Canada. ARMSPACH, Otto W * (Jf 1919). Chief Engr., Kroeschell Engrg. Co., 2306 N. Knox Ave., Chicago, and (for mail), 205 S. Summit Ave., . Dir., Mumford Bailey & Preston, Ltd., and Joint Managing Director, British Trane Co., Ltd. (for mail), "Newcastle House," Clerkenwell Close, London E. C. 1, and "Oldbury Court," Daines- - Villa Park, 111. ARMSTRONG, Robert W. (S 1935), 2809 E. Lake of the Isles Blvd., Minneapolis, Minn. ARNDT, Heinrich W. (A 1935), Salesman. Barrett Supply Co., 639 Broad St., and (for mail), 214 Third St., Augusta. Ga. ARNOLD, Robert S. (A 1926; 7 1922), Dist. Mgr., Hijet Sales, The Herman Nelson Corp., -1600 Arch St., Philadelphia, and (for mail), Wallingford. Pa. ARNOLDY, William F. (A 1930), Branch Mgr. (for mail), Minneapolis Honeywell Reg. Co., 2847 Grand River Ave., Detroit, and 520 SL Clair, Grosse Pointe, Mich. ARROWSMITH, John O. (Jf 1934). Plant Engr. (for mail), .Canadian Kodak Co., Ltd., and 9 Humberview Road, Toronto 9, Ont., Canada. ARTHUR, John M., Jr. (M 1923), Supt., Com mercial Light & Steam Sales (for mail), Kansas City Power & Light Co., 1330 Baltimore, Kansas City, Mo., and 3311 State Ave., Kansas City, Kans. - ASHLEY, Carlyle M.* (if 1931), Dir. of Research ' (for mail), Carrier Engrg. Corp., 750 Freling- huysen Ave., Newark,' and 270 Oakley Ave., Summit, N. j. ASHLEY, Edward E. (Jf 1912), Consulting Engr. (for mail), 10 East 40th St., New York, N. Y,, and P. O. Box 188, Noroton Heights, Conn. ASTON, James (Jf 1919), A. M. Byers Co., 235 Water St., Pittsburgh, Pa. way, Thorpe Bay, Essex, England. BAIRD, S. Alan (Jf 1935), Consulting Engr., 911 E. Virginia Ave., Peoria, 111. BAKER, C. T. (Af 1935), Consulting Engr. (for mail), 713 Glenn St. S.W., and 892 Piedmont Ave., Atlanta, Ga. BAKER, Harry L., Jr. (7 1935), Sales Engr. (for mail), American Blower Corp., 401 Broadway, New .York, and 301-100th St., Bay Ridge, Brooklyn, N. Y. BAKER, Howard C. (Jf 1921), The H. C. Baker Co., 128 S. St. Clair St., Toledo, Ohio. BAKER, Irving C. (Jf 1921), General Sales Mgr. (for mail), Airtemp, Inc., 8021 Conant Road, Detroit, and 1428 Yorkshire Road, Grosse Pointe, Mich. . BAKER, Roland H. (A* 1928; A 1924), Pres, (for mail), R. H. Baker Co., Inc., 145 Broadway, and 420 Memorial Drive, Cambridge, Mass. BAKER, William H., Jr. (A 1935), Boiler and Radiator Sales (for mail). Crane Co., 836 S. Michigan Ave., and 1211 N. State St., Chicago, 111. . . BALDWIN, William Howard (Jf 1921), Branch Mgr. (for mail), C. A. Dunham Co., '2988 E. Grand Blvd., and 2246 Calvert, Detroit, Mich. BALSAM, Charles P. (Jf 1932), 324 Fourth SL, Brooklyn, N. Y. BANNON, Lucas E. (A 1935), Archt., 16 Church St., Paterson, N. J. 8 Roll of Membership BARBERA, Henry A. (5 1932). 1727 Colden Ave.. New York, N. Y. BARBIERI, Patrick J. (5 1933), Engrg. Asst., Dwight D. Kimball, Consulting Engr., Room 1728 Grand Central Terminal Bldg., and (for mail), 2166 Belmont Ave., New York, N. Y. BARNES, Walter E. (Jf 1933), Pres., Barnes & Jones, Inc., 128 Brookside Ave., Jamaica Plain, Boston, and (for mail), 7 Woodlawn Ave., Wellesley Hills, Mass. BARNS, Amos A. (Jf 1933), Owner (for mail), 440 W. State St., and 318 W. State St., Ithaca, N. Y. BARNUM, Charles R. (S 1935), 1494 Capitol Ave., St. Paul, Minn. BARNUM, Marvin G. (Jf 1930; A 1928), R-1622, 1133 Broadway, New York, N. Y. BARNUM, Willis E., Jr. (M 1933; A 1933; 7 1930), Sales Engr., York Ice Machinery Co., 5051 Santa Fe Ave., Los Angeles, and (for mail), 3507 Santa Ana, South Gate, Calif, BARR, George W. (M 1905), (Board of Governors, 1910), Dist. Mgr., Aerofin Corp., Land Title Bldg., Philadelphia, and (for mail). Woods End, Villanova, Pa. BARRY, James G,, Jr. (M 1933), Vice-Pres. (for mail), Elliott & Barry Engrg. Co., 4060 W. Pine Blvd., and 5051 Queens Ave., St. Louis, Mo. BARRY, Patrick I. (Jf 1920), (Peace Commis sioner), MIHVE (for mail), M. Barry, Ltd,, 4 Marlboro St., and Budaka, Sidney Park, Cork, Ireland. . BARTH, Herbert E. (Af 1920), Sales Mgr., American Blower Corp., 6000 Russell St., Detroit, Mich. BARTLETT, Amos C. (Jf 1919), Mgr., Htg. and Vtg. Dept, (for mail), B. F. Sturtevant Co., Hyde Park, Boston, and 30 Hollingsworth Ave., Braintree, Mass. ' BARTLETT. C. Edwin (Af 1922), Pres, (for mail), Bartlett & Co., Inc., 1938 Market St., and 3111 W. Coulter St., Philadelphia, Pa. BARTON, Delbert H. (5 1935), Box 44 B, Somerville, and (for mail). Box 1088, S.E., College Station, Texas. BASTEDO, Albert E. (Jf 1919), Vice-Pres.Treas.-Mgr. (for mail), Burnham Boiler Corp., Irvington-on-Hudson, and Burnside Drive, Hastings-on-Hudson, N. Y. BAUER, Albert E. (Jf 1935), Engr., U. S. Air Cond. Corp., Minneapolis, and (for mail), 59 S. - Victoria St., St. Paul, Minn. BEGGS, William E. (Jf 1927), Pres., W. E. Beggs Co., 907 Lloya Bldg., and (for mail), 3639 Palatine Ave., Seattle, Wash. BEIGHEL, Howard Atlee (A 1927), Sales Repr. (for mail), The Herman Nelson Corp., 503 Columbia Bank Bldg., Pittsburgh, and 207 Puritan Road, Rosslyn Farms, Carnegie, Pa. BEITZELL, Albert E. (A 1933; 7 1930), Mgr., Air Cond. Div., Combustioneer Stoker Corp., Tenth and D Sts. S.W., and (for mail), 1475 Columbia Road, Washington, D. C. BELING, Earl H. (A 1930; 7 1925), 2428-13th SL, Moline, III. BELL, E. Floyd (M 1933), (for mail), 619 Foshay Tower, and 2605 Fremont Ave. S., Minneapolis, Minn. BEMAN; Myron C. (Jf 1926), (Council, 1934 1935), Consulting Engr. (for mail), Beman & Candee, 374 Delaware Ave., and 699 Richmond Ave., Buffalo, N. Y. BENNETT, Edwin A. (7 1929), Sales Engr. (for mail), American Blower Corp., 401 Broadway, New York, N. Y., and 45 Pondfield Road W., Bronxville, N. Y. BENNITT, George E. (Jf 1918), Consolidated Gas Co. of New York, 4 Irving Place; New York, N. Y. BENOIST, LeRoy L. (Jf 1934), Mgr. (for mail). Benoist Bros., Hardware and Supply, 117 S. Tenth St., and 1500 Main SL, Mt. Vernon, 111- BENSE, William M. (5 1934), Engr., Institute of Thermal Research (for mail), American Radiator Co., 675 Bronx River Road, Yonkers, and 340 Hayward Ave., Mt. Veraon, N. Y. BENSEN, Clarence L. (7 1935), Engr. (for mail), McQuay, Inc., 1600 Broadway N.E., Minne apolis, and 1663 Berkeley Ave., St. Paul,'Minn. BENTZ, Harry (Jf 1915), 18 Holland Terrace. Montclair, N. J. BERCHTOLD, Edward W. (M 1927; A 1925), Rate Engr. (for mail), Boston Consolidated Gas Co., 100 Arlington St., Boston, and 20 Randolph St. S.f Weymouth, Mass. BERGHOEFER, Victor A. (7 1926), Vice-Pres., Sterling Engrg. Co., 3738 N. Holton, and (for mail), 4129 North 20th St., Milwaukee, Wis. BERMAN, Louis K. (Jf 1908), Pres, (for mail). Raisler Heating & Sprinkler Cos., 129 Amsterdam Ave., and 101 Central Park W., New York, N. Y. BERMEL, Alfred H. (A 1933; 7 1928), Mech. Engr. and Estimator, August Arace & Sons, Inc., 342 Third Ave., Elizabeth, and (for mail), 16 BAUGHMAN, L. R. (M 1935), Htg. Engr., William St., North Arlington, N. J. Modem Plumbing & Heating Service, and (for . BERNHARD, George (Jf 1935; A 1929). Manag mail), 2706 Escbol Ave., Zion, 111. . ing Engr., Associated Heating Co., 16 Lafayette BAUM, Albert L. (Jf 1916), Member of Firm (for mail), Jaros Baum & Bolles, 415 Lexington Ave., Ave., and (for mail), 985 Park Place, Brooklyn, N. Y. . and 601 West 113th St,, New York, N. Y. . BERNSTROM, Bert (Jf 1930), Engr., Research BAUMGARDNER, Carroll Miles (Jf 1928), Branch Mgr. (for mail), U. S. Radiator Corp., 3254 N. Kilbourn Ave., Chicago, and 602 Michigan Ave., Evanston, 111. BAUR, John W. (5 1935), 2517 Leland Ave., Chicago, and (for mail), 1004 S. Second St., . Champaign, 111. BAYSE, Harry V. (Jf 1923), American Furnace Co., 2725 Morgan St., St. Louis, Mo. BEAN, George S. (A 1935), Mgr. Stoker Div., Northwestern Fuel Co;, and (for mail), 4949 -16th Ave. S., Minneapolis, Minn. and Development Dept., Holland Furnace Co., and (for mail), P. O. Box 204, Holland, Mich. BEST, Millard W. (A 1933), Pres, (for mail), Kolelectric Underfeed Stoker Co., Ltd., 245 Kenilworth Ave. S,, and 1750 King SL E., Hamilton, Ont., Canada. BETLEM, Henriette T. (7 1934), Air Cond. Engr. (for mail), Betlem Heating Co., 1926 East Ave., and 1293 Park Ave., Rochester, N. Y. BETTS, Howard M. (if 1927), Senior Mech. Engr., Htg. and Vtg. (tor mail). Dept, of Bldgs., City of Minneapolis, 213 City Hall and 4923 Russell Ave. S., Minneapolis, Minn. ' BEARD, Earl L. (S 1934), Air Cond. Engr., BETZ, Hairy D. (Jf 1928), Pres, (for mail), Betz Albert Ahrens Co., Harvey at Sixth, and (for Unit Air .Cooler Co., 6 W. Ninth St., and 4210 mail), 736 East 13th St., Oklahoma City, Okla. Mercer, Kansas City, Mo. BEAURRIENNE, Auguste* (Jf 1912), Consulting ,, BICHOWSKY, F. Russell (Jf 1935), Engr., Air Engr., 25 Rue des Marguettes, Paris, France. Cond. Div. (for mail). Surface Combustion BEAVERS, George R. (Jf 1929), Chief Engr., Canadian Blower & Forge Co., Ltd., Woodside Ave., and (for mail), 168 Samuel St., Kitchener, Ont., Canada. BECKER, Walter A. (Jf 1935). Sales Engr., . Grinnell Co., Inc., 4425 S. Western Ave., and (for ' mail), 5651 N. Artesian Ave., Chicago, 111. BEEBE, Frederick E. W. (A 1915), Johnson Service Co., 28 East 29th St., New York, N. Y. Corp., Toledo, and 3421 Indian Road, Ottawa Hills, Ohio. BILYEU, William F. (Jf 1927), Eastern Div. Mgr. (for mail). The Trane Co., 250 East 43rd . SL, New York, and Gibson Apt., Flushing, L. I., N. Y. BINDER, Charles G. (Jf 1920), Mgr., Htg. DepL, Warren Webster & Co., 17th ana Federal Sts.,. Camden, and (for mail), 115 Oak Terrace,. Merchantville, N. J. ' 9 1936American Society of Heating and Ventilating Engineers Guide, BINFORD, Wilmer M. (J 1930), Mgr., Contract Dept., So. Div. (for mail). Plant Rubber & Asbestos Works, 2120 East 25th St., and 6215 San Vicente Blvd., Los Angeles, Calif. BIRD, Charles (A 1934), Treas. and Gen. Mgr. (for mail), The Doermann-Roehrer Co., 450-56 E. Pearl St., and Box 179-D, Section Road R. R. 6, Cincinnati, Ohio. BIRRELL, Allan L. (A 1925), Consulting Engr., 372 Bay SL, Toronto 2, and (for mail), 93 Kingsway. Toronto 9, Ont., Canada. BISCH, Bernard J. (M 1931), Engr., St. Mary-of- the-Woods College, St. Mary-of-the-Woods, Ind. BISHOP, Charles R. {Life Member; M 1901), 413 Locust St., Lockport, N. Y. BISHOP, Frederick R. (M 1921), Mfgre. Agent, 8011 Dexter Blvd., Detroit, Mich. * BISHOP. Marion W. (J 1935), Sales Engr. (for mail), American Blower Corp., 228 N. LaSalle St., and 6317 N. Kenmore Ave., Chicago, 111. BJERKEN, Maurice H. (A 1927), Dist. Repr. (for mail), Hoffman Specialty Co., 533 S. Seventh St., and 4952-17th Ave. S., Minneapolis, Minn. BLACK, Edgar N., 3rd (M 1922), Philadelphia Mgr., Fitzgibbons Boiler Co., Inc., 1215-1216 Land Title Bldg., Philadelphia, and (for mail), 111 Woodside Road, Haverford, Montgomery Co., Pa. BLACK, F. C. (Af 1919), Pres, (for mail), F. C. Black Co., 622 W. Randolph St., and 4535 N. Ashland Ave., Chicago, 111. BLACK, Harry G. (Af 1917), Prop, (for mail), P. Gormly Co.. 155 N. Tenth St., and 927 North ` 65th St.. Philadelphia, Pa. BLACK, William B. (J 1932), Bryant Heater Co., 135 Seward Ave., Bradford, Pa. BLACKBURN, Edwin C., Jr. (M 1929), Con sulting Engr., Crow, Lewis & Wick, 200 Fifth Ave., New York, and (for mail), 27 Lucille St., Hempstead, L. I., N. Y. BLACKHALL, Lewis C. (M 1935), Engr. (for mail), Gurney Foundry Co.. Ltd., 4 Junction Road, Toronto, and 234 Brock Ave., Toronto, Canada. BLACKHALL, Wilmot R. {M 1922), Partner (for mail), McKellar & Blackhall. 1104 Bay St., and 332 Waverley Road, Toronto, Canada. BLACKMAN, Alfred O. (M 1911), Consulting Engr. (for mail), 145 West 45th SL, and 149 West 12th St., New York, N. Y. BLACKMORE, F. H. (M 1923), Mgr., Operating Dept, (for mail), U. S. Radiator Corp., Box 686 Detroit, and 515 Tooting Lane. Birmingham, Mich. BLACKMORE, George C. {Charter Member; Life Member), Pres, (for mail). Automatic Gas Steam Radiator Co., 301 Brushton Ave., and Cathedral Mansions. Pittsburgh, Pa. BLACKMORE, J. J.* {Charter Member; Life Member), 32 West 40th St.. New York. N. Y. BLACKMORE, James S. (J 1931). Sales Engr., ' H. A. Thrush & Co., Peru, lnd., and (for mail), 330 E. Manor Road, Upper Darby, Pa. BLACKSHAW. J. L.* (J 1929), Engr., Air & Refrigeration Corp., 11 West 42nd St., New York, and (for mail), 59 Joralemon St., Brooklyn, N. Y. BLAIR, Howard A. {J 1036), Service Engr., Air Cond. Equip., Westinghouse Electric & Mfg. Co., Mansfield, Ohio. BLAKELEY, Hugh J. {M 1935), Consulting Engr., Hubbard, Rickerd & Blakeley, 1109 Chapel St., New Haven, and (for mail), 5 Doty Place, Morris Cove, Conn. BLAKESLEE, Donald {A 1935), Pres, (for mail), Donald Blakeslee, Inc., 89 Main St., Patchogue, and Bellport, N. Y. BLANDING, George H. {M 1919), 800 N. Lombard Ave., Oak Park, 111. . BLANKIN, Merrill F. {M 1927; A 1926; J 1919), Pres.' (for mail), Haynes Selling Co., Inc., 1518 Fairmount Ave., and 3328 W: Penn St., Phila delphia, Pa. BLESSED, William A. {A 1935), Mech. Engr. (for mail), Mueller Brass Co., and 515-15th SL, Port Huron, Mich. . BLISS, George L. {A 1933), Engr. and Sales (for mail), Allis-Chalmers Mfg. Co., 1410 Waldheim Bldg., 11th and Main, and 7641 Brooklyn Ave., Kansas City, Mo. . BLOOM, Louis {M 1935), Partner, B. Bloom & Son, 1450-*52nd St., Brooklyn, N. Y. BOALES, William G. {M 1935; A 1923), Pres, (for mail), Wm. G. Boales Co., 6537 Hamilton Ave., Detroit, and 195 McMillan Road, Grosse . Pointe Farms, Mich. BOCK, Bernard A. {A 1929; J 1927). Engrg. Draftsman. 425 Beech St., Arlington, N. J. BOCK, I. I. {A 1934), Sales Engr. (for mail). Carrier Engrg. Corp., 2022 Bryant St., and 2500 South Blvd., Dallas, Texas. BODDINGTON, William P. {M 1927), Mgr. (for mail). The Canadian Powers Regulator Co., Ltd., 106 Lombard St., and 280 Clendenan Ave., Toronto, Ont., Canada. BODINGER, Jacob H. {M 1931), Pres, (for mail), Bodinger & Co., Inc., 530 Tenth Ave., New York, and 1429 East 19th St., Brooklyn, N. Y. BOEHMER, Andrew P. (S 1935), 3012 N. Kostner Ave., Chicago, III. BOGATY, Herman S. {M 1921), 5230 North 15th SL, Philadelphia, Pa. BOLS1NGER, Raymon C. {M 1916), Prop, (for mail). Automatic Florzone Htg. Co., 309 E. Main St., Norristown, Pa., and Collingswood, N. J. BOLTE, E. Endlcott (A 1929), Salesman, National Radiator Corp., 1111 East 83rd SL, and (for mail), 6516 Kenwood Ave., Chicago. 111. BOLTON, Reginald Pelham* {Life Member; M 1897), {Presidential Member), (Pres., 1911; 1st Vice-Pres.. 1905-1910; 2nd Vice-Pres., 1903> Board of Governors, 1901, 1905, 1910, 1911, 1912, 1913), The R. P. Bolton Co.. 116 East 19th SL. New York, N. Y. BOND, Horace A. {M 1930), DisL Mgr., Warren Webster & Co., 152 Washington Ave., and (for mail), 12 Ramsey Place, Albany, N. Y. BONTHRON, Robert C. {A 1935), Mgr., Air Cond. Sales, Westinghouse Electric 8c Mfg. Co., 3001 Walnut St., Philadelphia, and (for mail), 139 Strathmore Road, Upper Darby, Pa. BOOTH, C. A. {M 1917), Vice-Pres. (for mail), Buffalo Forge Co., 490 Broadway, and 142 Summit Ave., Buffalo, N. Y. BOOTH, Harry N. {M 1924; A 1917), Vice-Pres.. Sales Dept, (for mail), U. S. Radiator Corp., Room 1056 First National Bank Bldg., and 2916 Seminole Ave., Detroit, Mich. BORLING, John R. {A 1934), Engr., Custodian, Board of Education, 6520 S. Wood SL, and (for mail), 953 84th Place, Chicago, 111. BORNEMANN, Walter A. {M 1924; J 1923), Sales Engr. (for mail). Carrier Engrg. Corp., 12 South 12th St.. Philadelphia, and 123 W. Wharton Ave., Glenside, Pa. BORUCH,. Edwin R. {A 1935), Air Cond. Sales Engr. (for mail), Dallas Power & Light Co., 1506 Commerce SL, and 835 N. Bishop, Dallas, Texas. BOUCHERLE, Henry N. (M 1934). Secy, (for mail), The Scholl-Choffin Co., Mahoning Ave. and Hogue St., and 3412 Hudson Ave., Youngs town, Ohio. BOUEY, Angue J. (J 1930), Sales Engr. (for mail), B. F. Sturtevant Co., 553 Monadnock Bldg., and 4810 Fulton St., San Francisco, Calif. BOUILLON, Lincoln {M 1933), Consulting Engr. (for mail), 1411 Fourth Ave. Bldg., and 4186 42nd Ave. N.E., Seattle, Wash. BOWDITCH, Robert P. (5 1935), 504 S. Race St., Urbana, 111. BOWERS, Arthur F. {A 1919), Pres., Industrial Htg. & Engrg. Co., 828 N. Broadway, Mil waukee, Wis. BOWERS, Ross C. (A 1932), Branch Mgr. (for mail), Minneapolis-Honeywell Regulator Co., 335 W. North Ave., and 3773 North 52nd SL. Milwaukee, Wis. BOWLES, Potter (A 1928), Pres, (for mail). Hoffman Specialty Co., Inc., Room 3324, 500 Fifth Ave., New York, and 678 Ely Ave., Pelham Manor, N. Y. 10 Roll of Membership BOWMAN, James W. (5 1934), 210 S. Santa Fe Norman, Olda. BOYDEN, Davis S* {M 1909), (Treas., 1933 1934; Council, 1930-1935), Supt., Steam Htg. Service DepL (for mail), Edison Electric Illumi nating Co. of Boston, 39 Boylston SL, Boston, and 1496 Commonwealth Ave., Brighton, Mass. BOYKER, Robert O. {J 1935), Contractor, Mac Boyker & Son, Kent, Wash. BRAATZ, Chester Johnson* (Af 1930), Engr., Temp. Control Div., Barber-Colman Co., and (for mail), 718 King SL, Rockford, 111. BRABBLE, Dr. Charles W.* {M 1925), (for mail), American Radiator Co., 40 West 40th SL, New York, and 50 Lincoln Ave., Tuckahoe, N. Y. BRACKEN, John Henry {M 1927), Mgr., Industrial Uses Dept, (for mail). The Celotex Co., 919 N. Michigan Ave., Chicago, 111. BRADFIELD, W. W. {M 1926), Consulting Engr. (for mail), 901 Michigan Trust Bldg., and 1352 Franklin St. S.E., Grand Rapids, Mich. BRADLEY, Eugene P. {M 1906), Pres, (for mail), Hester-Bradley Co., 2835 Washington Ave., and 6935 Pershing Ave., St. Louis, Mo. BRAEMER, William G. R. {M 1915), (for mail), Wm. G. R. Braemer & Josiah H. Smith Engrs., Room 1265 Commercial Trust Bldg., Phila delphia, Pa., and 223 Chestnut St., Haddonfield, N. J. ' BRANDI, O. H. {M 1930), Dipl. Ing., Rud. Otto Meyer, Hamburg 23, Pappelallee 23-39, and (for mail), Altona, Gr.t Flottbek, Gottorpstr 1, Germany. BRANDT, Ernst Hamilton, Jr. (M 1928), Pres., Reliance Engrg. Co., Inc., 515 N. Church St., and (for mail), P. O. Box 292, Charlotte, N. C. BRAUER, Roy {M 1926), Pres, (for mail). Venti lating Equip. Corp., 1101 Bessemer Bldg., Pittsburgh, and R. F. D. No. 1, Hillcrest Library, Pa- BRAUN, John J. {M 1932), Factory Mgr., The U. S. Playing Card Co., Norwood Station, Cincinnati, and (for mail), 4305 Floral Ave., Norwood, Ohio. BRAUN, Louis T. {M 1921), Executive Secy, (for mail), Chicago Master Steamfitters Assn., 228 N. LaSalle St., and 1548 Pratt Blvd., Chicago. 111. BRECKENRIDGE, L. P * {Life Member; M 1920), The Brackens, North Ferrisourg, VL . .BREDESEN, Bernhard P. (A 1931), Htg. and Vtg. Engr. (for mail), Herman Nelson Corp., 410 Essex Bldg., and 3119 Knox Ave., N.t Minne apolis. Minn. BREITENBACH, George C. {M 1933; A 1933; J 1928), Sales Mgr. (for mail). The Trane'Co., Room 224, 1600 Arch St.. Philadelphia, and 300 Essex Ave., Narberth, Pa. BRENEMAN, Robert B. (A 1931; J 1927), Sales Engr. (for mail), Armstrong Cork & Insulation ,, Co., 232 W. Seventh SL, and 1557 Addingham Place, Cincinnati, Ohio. BRENNAN, John W. {M 1935; A 1934), Salesman (for mail), American Blower Corp., 801 Hofmann Bldg., and 5944 Yorkshire, Detroit, Mich. BRIDE, William T. (Af 1928; A 1928; J 1925), Supt. Engrg. (for mail). P. O. Box 777, Lawrence, and 50 High St., Methuen, .Mass. BRIGHAM, Clare M. {M 1935), Vice-Pres. in ' Charge of Sales (for mail), C. A. Dunham Co., 450 E. Ohio St., Chicago, and 420 Maple Ave., Winnetka, III. BRIGHAM, Frederick H. (Af 1930), Sales Engr.. G. H. Gleason & Co., 25 Huntington Ave., Boston, and (for mail), 80 Bedford SL, Lexing ton. Mass. BRINKER, Harry A. {M 1934), 524 Village SL. Kalamazoo, Mich. BRINTON, Joseph Ward {M 1920), DisL Mgr. (for mail), American Blower Corp., 1003 Statler Bldg., Boston, and 42 Gleason SL, West Med ford. Mass. BRISSETTE, Leo A. {M 1930), Treas. (for mail). Trask Htg. Co., 4 Merrimac St., Boston, and 168 Florence SL, Melrose, Mass. BRODERICK, Edwin L.* {M 1933). Research Asst, (for mail), 210 M. E. Lab., University of IUi- nois, Urbana, and 909 S. First SL, Champaign, 111. BRONSON, Carlos E.* (Af 1919), Mech, Engr. (for mail), Kewanee Boiler Corp., and 311 McKinley Ave., Kewanee, III. BROOKS, Frank W. (S 1934), 935 N. Broadway, Dayton, and (for mail), 2111 Abington Road, Cleveland, Ohio. BROOM, Benjamin A. {M 1914), Sales Pro. Engr., Weil McLain Co., 641 W. Lake SL, and (for mail), 1544 Sherwin Ave., Chicago, 111. BROOME, Joseph H. (A 1935), 1556 Pacific SL, Brooklyn, N. Y. BROWN, Alfred P. {M 1927), Vice-Pres. (for mail), Reynolds Corp., 609 N. LaSalle SL, Chicago, and 551 Hill Terrace. Winnetka, 111. BROWN, Aubrey I.* (M 1923), Prof, of Htg. and Vtg. (for mail), Ohio State University, and 169 Richards Road, Columbus, Ohio. BROWN, Foskett* (Af 1926). Vice-Pres. (for mail). Gray & Dudley Co., 222 Third Ave. N., P. O. Box 722, and 2314 West End Ave., Nash ville, Tenn. BROWN, Morris (J 1928), Htg. Engr. (for mail). Brown Bros., 340 Talbot Ave., and 609 Park St., Dorchester, Mass. BROWN, Norman A. (S 1935), 4723 West 19th St., Cicero, 111. BROWN, Ronald F. (5 1933), 66 Mitchell Ave.. Binghamton, N. Y,, BROWN, Tom (M 1930). Vice-Pres. and Gen. Mgr. (for mail). Autovent Fan & Blower Co., 1805 N. Kostner Ave., and 5325 N. Laramie Ave., Chicago, III. BROWN, William A. (M 1930), Consulting Engr., Cucci & Brown, 347 Madison Ave., New York, N. Y., and (for mail), 5507 Carolina Place N.W., Washington, D. C. BROWN, William H. (A 1923), Mgr., Brown Bros., 3312 W. North Ave., and (for mail), 3015 North 22nd SL, Milwaukee, Wis. BROWN, W. Maynard (A 1930), Warren Webster & Co., 17th ana Federal Sts., Camden, N. J. BROWNE, Alfred L. (Af 1923), 253 Highland Ave., South Orange, N. J. BRUEGGEMAN. Arthur R. (if 1920), (for mail). The Erie Engrg. Co., 1740 East 12th SL, Cleve land, and 17220 Aldersyde Drive, Shaker Heights, Ohio. BRUNETT, Adrian L. (Af 1923), Assoc. Mech. Engr., U. S. Supervising Architects Office, Treasury Dept., Washington, D. C., and (for mail), P. O. Box 36, Rockville. Md. BRUST, Otto (Af 1930), Dipl. Ing., CarrierPraha 1, Revolucni 13. and (for mail), Praha VII, Veverkova 3, Cechoslowakia. BRYANT, Dr. Alice G. (M 1921), 405 Marl borough St., Boston, Mass. BRYANT, Percy J. (M 1915), Chief Engr. (for mail). Prudential Insurance Co., 783 Broad SL, Newark, and 754 Belvidere Ave., Westfield. N. J. BUCK, Lucian (M 1928), Pres, (for mail). Buck Dryer Corp., P. O. Box 308, Manchester. Conn. BUCKLEY, Martin B. (A 1930), 824 Grand Ave., Kansas City, Mo. BUENGER, Albert* (M 1920; J 1917), (Council. 1934-1935), Mech. Engr. (for mail), C. H. Johnston, ArchL, 715 Empire Bank Bldg., and 1666 Stanford Ave., St. Paul, Minn. BUENSOD, Alfred Charles (Af 1918), Pres., Buen- sod Stacey Air Conditioning, Inc., 60 East 42nd . SL, and (for mail). 1 Fifth Ave.. New York. N. Y. BULKELEY, Claude A.* (Af 1923). Chief Engr. (for mail), Niagara Blower Co., 6 East 45th SL, and 410 West 58th SL. New York. N. Y. BULLEIT, Charles R. (Af 1932; A 1932; J 1930), 1811 Bayard Park Dnve, Evansville, lnd. BULLOCK, Howard H, (A 1933), Commercial Engr. (for mail). General Electric Co., 6201 Santa Fe Ave., Los Angeles, and 2530 Grand SL, Walnut Park, Calif. BULLOCK, Thomas A. (Af 1930), Engr. (for mail), Densmore LeClear & Robbins, 31 SL James Ave., Boston, and 35 Everett St., Arling ton, Mass. 11 American Society of Heating and Ventilating Engineers Guide, 1936 BUQT, Antonio V. (S 1935), 2730 Portland Ave. - S., Apt. 105, Minneapolis, Minn. BUR, Julien R. C. (7 1931). Chief Engr. (for mail). Bur & Co., 10 rue du Chapeau Rouge, and : 1 Place Francois Rude, Dijon, France. BURBAUM, W. Allen (7 1933), 180 Clinton ' . Ave., Brooklyn, N. Y. BURCH, Lawrence A. (Af 1934), Mgr., Htg. Div., Perfex Radiator Co., 414 E. Oklahoma . Place, and (for mail), 421 E. Lloyd St., Mil waukee Wis. BURKE, James J. (7 1930), Engr., Carrier Engrg. Corp., 12 South 12th St., Philadelphia, Pa. BURKE, William J. (A 1934), 2375 S.W. Ninth . St., Miami, Fla. BURKHART, Elder M. (7 1935), Asst. Htg. and Vtg. Engr., W. G. McIntosh, 219 E. Cunningham St., Butler, and (for mail), 542 E. Tenth Ave., Tarentum, Pa. BURKS, Roland H. (S 1935), 120 Second St.. Detroit, Mich. BURNETT, Earle S. (Af 1920), Mech. Engr.. Amarillo Helium Plant, U. S. Bureau of Mines, 1 and (for mail), 4223 W. Eleventh Ave., Amarillo, Texas. BURNS*, E. J. (Af 1923), Harris Bros., 217 W. Lake St., and (for mail), 4716 Aldrich Ave. S., Minneapolis. Minn. BURNS, John R. (S 1933). Htg. Engr., Delius Co., 43 N. Main St., and (for mail), 504 N. Main St., Wallingford, Conn. . BURNS, Robert (M 1934), Sales Engr., Sears Roebuck & Co., 200 E. Ohio St.,.and (for mail), 482 Antenor Ave., Pittsburgh, Pa. BURRITT, Charles G. (A 1916), Mgr., Minne apolis Office (for mail), Johnson Service Co., 922 .. Second Ave. 5., and Buckingham Hotel, Minne apolis, Minn. BUSHNELL, Carl D. (A 1921), Pres, (for mail). The Bushnell Machinery Co., 1501 Grant Bldg., Pittsburgh, and 94 Pilgrim Road, Rosslyn Farms, Carnegie, Pa. BUTLER, Peter D. (Af 1922), Salesman, U. S. Radiator Corp., 370 Lexington Ave., New York, N. Y., and (for mail), 127 Edgewater Road, Grantwood, N. J. . . BUTT, Roderick E. W. (7 1930), Partner, Crerar, Butt & Co., 14 Regent St., London S.W.I., and (for mail), 3 Orme Court, London W 2, England. BUTTARAVOLI, Frank (S 1935). 1820 East 19th St., Brooklyn, N. Y. , BUTTS, Robert L. (S 1935), 64th and Norman- dale, Minneapolis, Minn. G CALDWELL, Arthur C. (Af 1930), Estimator ' and Engr., P. Gonnly Co., 155 N. Tenth St., and (for mail), 550 South 48th St., Philadelphia, Pa. CALEB, David (Jlf 1923), Engr. (for mail), Kansas City Power & Light Co.,-1330 Baltimore Ave., and 141 Spruce St., Kansas City, Mo. CALLAGHAN, Philip F., Jr. (,J 1929), Sales Mgr., DGC Trap & Valve Co., Inc., 9 East 46th SL, New York, and (for mail), 3001 Ave. I., Brooklyn, N. Y. CALLAHAN, Peter J. (Af 1934), Inspecting Engr., Central Hanover Bank & Trust Co.; 60 Broad- way. New York,' and (for mail), 4057 Amboy Road, Great Kills, Staten Island, N. Y. CAMPBELL, Alfred Q. (7 1933), Ford Moter Co., and (for mail), 1083 Meriwether Ave., . Memphis, Tenn. CAMPBELL, Everett K.* (Af 1920), Pres, and . Treas. (for mail), E. K. Campbell Htg. Co., 2445 ' V , Charlotte St., and 3717 Harrison Blvd.. Kansas i' ' City, Mo. ' CAMPBELL, E. Klrker (7 1930), (for- mail), E. K. Campbell Htg. Co., 2445 Charlotte St., and 3713 Harrison Blvd., Kansas City, Mo. CAMPBELL, Frank B. (A 1927), Sales Engr. (for mail), American Radiator Co., 40 West 40th St., New York; and 245 Macon St., Brooklyn, N. Y. ` CAMPBELL, Robert E. (7 1935; S 1934), Htg. Engr. (for mail), Brooklyn Borough Gas Co., Coney Island, and 1033 Ocean Ave., Brooklyn, N. Y. CAMPBELL, Thomas F. (Af 1928), Minneapolis- Honeywell Regulator Co., 1013 Penn Ave., Wilkensburg, Pa. CANDEE, Bertram C. (Af 1933), Partner, Beman & Candee, 374 Delaware Ave., Buffalo, and (for mail), 19 Tremont Ave., Kenraore, N. Y. CAREY, James A. (Af 1928), Carrier Engrg. Corp., Newark, N. J,, and (for mail), Villanova, Pa. CAREY, Paul C. (Af 1930), (for mail), Runyon & Carey, 33 Fulton St., Newark, and 31 Claremont Drive, Maplewood, N. J. CARLE, William E. (Af 1926), Pres, (for mail). Carle, Boehling Co., Inc., 1641 W. Broad St., and 2220 Floyd Ave., Richmond, Va. CARLSON, Everett E. (Af 1932; A 1929), Branch Mgr. (for mail). The Powers Regulator Co., 1010 Louderman Bldg., and 6652 Washington Ave., St. Louis, Mo. CARMAN, George G. (A 1931; 7 1928), Lewis Institute, Chicago, 111. CARPENTER, R. H. (Af 1921), (Council, 1930 1935), Mgr., New York Office (for mail), Nash Engrg. Co., Graybar Bldg., 420 Lexington Ave., New York, and 20 Jefferson Ave., White Plains, N. Y. . CARR, Maurice L. (Af 1931), Dir. (for mail), Pittsburgh Testing Lab., P. O. Box 1646, and Webster Hall, Pittsburgh, Pa. CARRIER, Earl G. (7 1929), Estimating Engr., Carrier South Africa (Pty) Ltd., 20 Beresford - House Simmonds St., Johannesburg, Transvaal Union of South Africa. CARRIER, Willis H.* (Af 1913), (Presidential Member), (Pres., 1931; 1st Vice-Pres., 1930; 2nd Vice-Pres.. 1929; Council, 1923-1932), Chairman of the Board (for mail). Carrier Engrg. Corp., 850 Frelinghuysen Ave., Newark, and Rensselaer Road, Essex Fells, N. J. CARTER, Doctor (Af 1934), Htg. and Sanitary Engr. (for mail), Room 415, 410 Szechuen Road, and Lane 175, House 9, Tunsin Road, Shanghai, China. CAREY, Edward B. (Af 1935), Vice-Pres. (for mail), John Paul Jones Carey & Millar, Inc., Consulting Engrs., 448 Terminal Tower, Cleve land, and 3549 Daleford Road, Shaker Heights, Ohio. CASE, Walter G. (A 1930), Tech. Mgr., Ideal Boilers & Radiator, Ltd., Ideal House Gt., Marlborough St., London W I., and (for mail), 66 The Ridgeway, Kenton, Middlesex, England. CASEY, Byron L. (Af 1921), Sales Engr. (for mail), Ilg Electric Vtg. Co., 182 N. LaSalle St., Chicago, and 515 N. Park Ave., Park Ridge, III. CASEY, Huntley F. (Af 1931), Mech. Engr., Treasury Dept., Proc. Div., Federal Warehouse, Washington, D. C., and (for mail), P. O. Box 271 E. Falls Church, Va. CASH, Tidle T. (A 1925), Mgr. (for mail), Grinnell Co., Inc.. 240 Seventh Ave. S./and 617 Kenwood Pkwy., Minneapolis, Minn. CASPERD, Henry W. H. (.J 1930), Engr., Carrier Engrg. Co., Ltd., 24 Buckingham Gate, London, and (for mail), 21 Robin Hood Lane, Sutton, Surrey, England. CASSELL, John D.* {Life Member; Af 1913). (Council, 1930-1935), Retired (for mail), 2008 Walnut St,, Philadelphia, Pa., and 740 Garfield Ave., Palmyra, N. J. . CASSELL, William LJ (Af 1935), Consulting Engr. (for mail), 2501 Telephone Bldg., Kansas City, and R. F. D. No. 6, Independence, Mo. CAWBY, Elmer L. {J 1935), Air Cond. Engr. (for mail). Carrier Engrg. Corp., 748 E. Washington Blvd., and 701S. Grammercy Drive, Los Angeles, Calif. CHAPIN, C. Graham (Af 1933), Treas. (for mail), Hopson & Chapin Co., 231 State St., and 66 Faire Harbour Place, New London, Conn. 12 Roll op Membership CHAPIN. Harvey G. (Af 1935), Air Cond. Engr. (for mail), York Ice Machinery Corp., York, Pa., . and 8136 Ingleside Ave., Chicago, 111. CHAPPELL, Henry D. {M 1931), Dist. Mgr., V-Be!t Drive Co., 100 Morgan Bldg., and (for mail), 8019 Third Ave., Detroit, Mich. CHARLES, Thomas J. (Af 1934). Pres. (fOT mail), Metropolitan Air Cond. Co., 432 Fourth Ave., New York, and 175 Marine Ave., Brooklyn, N. Y. CLEGG, Carl (Af 1922), Dist. Mgr. (for mail), American Blower Corp., 311 Mutual Bldg., and 3321 GiUham Road, Kansas City, Mo. CLEGG, Robert R. (A 1933), Zone Mgr. (for mail), Owens-Illinois Glass Co., Industrial Materials Div., 1463 LaSalle Wacker Bldg., and 3270 Lake Shore Drive, Chicago, III. CLERICUZIO, Gerald P. (7 1935), 87 Grove SL, Bloomfield, N. J. CHARLET, Louis W. (Af 1934), Mgr., N. Y. Branch (for mail), Kewanee Boiler Corp., 37 West 39th St.r New York, and 427 Rich Ave., Mt. Vernon, N. Y. CHARLTON, John Felder (A 1932), Engr., CLODFELTER, John L. (A 1932), Supt. (for mail), Carolina Sheet Metal Corp., 4210 Sansom St., Philadelphia, and West Chester Pike and. Brief Ave., Elizabeth Manor Apt., Upper Darby, Pa. Appraiser (for mail). Box 2087, and 1631 N.E. CLOSE, Paul D.* (Af 1928), Chief Engr.. In Fifth St., Ft. Lauderdale, Fla. . dustrial Uses Div. (for mail), Celotex Co., 919 CHASE, Chauncey L. (Af 1931), Htg. and Vtg. Engr., Edward E. Ashley, 10 East 40th St., New N. Michigan Ave., Chicago, and 4622 Grove, Niles Center, 111. . York, and (for mail), 8829 Ft. Hamilton Pkwy., Brooklyn, N. Y. . CHASE, Louis R. (J 1931), Mgr., Air Cond. Div. CLOUGH, Leslie (Af 1922), Consulting Engr. (for mail). Box 34, and 203 Pierce Road, Weymouth, Mass. (for mail). The Carter-Waters Corp., 2440 Pennway, and 5239 Rockhili Road, Kansas . City. Mo. . CHEESEMAN, Evans W. (S 1934), Carnegie Inst, of Tech., Pittsburgh, Pa. CHERNE, Real to E. (7 1929), Carrier Australasia, . Ltd., 49 Forbes St., Sydney N.S.W., Australia. CHERRY, Lester A,* (Af 1921), Consulting Engr. (for mail). Industrial Planning Corp., 271 Delaware Ave., Buffalo, and 155 Euclid Ave., Kenmore, N. Y. .. CHERVEN, Victor W. (Af 1928; A 1920), Chief . Engr. (for mail), Holland Furnace Co., and 326 Maple Ave., Holland, Mich. CHESTER, Thomas* (Af 1917), Consulting Engr., 949 Chicago Blvd., Detroit, Mich. CHESNUTT, N. Phelps (S 1934), Engr., District Southern Union Gas, Pyote, Texas. . COCHRAN, Charles C. (A 1935), Br. Mgr. (for mail). Minneapolis-Honeywell Reg. Co., 325 W. North Ave., and 2645 North 60th St., Mil waukee, Wis. COCHRAN, Lex H. (M 1934), Dist. Mgr. (for mail), American Blower Corp., Rialto Bldg., and 130 Camino Del Mar, San Francisco, Calif. COCHRAN, William B. (S 1935), Air Cond. Engr., Straus, Frank Co., 1819 Travis St., and (for mail). Route 1, Box 16, Telephone Road, Houston, Texas. COE, Ralph T. (Af 1917), Prop, (for mail), The R. T. Coe Cos., 400 Reynolds Arcade, and 235 Chile Ave., Rochester, N. Y. COHAGEN, Chandler C. (Af 1919), Archt., Mclver & Cohagen, 211 Hedden Bldg, (for mail) P. O. Box 2100, and 127 Wyoming Ave., Billings. Mont. . CHEYNEY, Charles C. (A 1913), Asst. Sales Mgr. (for mail), Buffalo Forge Co., 490 Broad way, and 255 Lincoln Pkwy., Buffalo, N. Y. CHIPPERFIELD, W. H. {A 1934), Service Engr., COHEN, Philip (Af 1932), Dist. Mgr. (for mail), B. F. Sturtevant Co., 407 E. Ohio Gas Bldg., Cleveland, and 3681 Lynnfield Road, Shaker Heights, Ohio. Waiker-Crosweller Co., Ltd., 20 Queen Elizabeth St. S.E.L, and (for mail), 54 Lankers Drive, N. Harrow, Middlesex, England. . . CHOFFIN, C. C. (M 1919), Pres-Treas. (for mail). The W. J. Scholl Co. Mahoning Ave., and Hogue St., and 450 Catalina Ave., Youngstown, Ohio. . CHRISTENSON, Harry (A 1931), Secy-Treas. COLBY, Clyde W. (M 1915), Consulting Engr. (Air Cond.), 1215 Main St-, Sprinfield, Mass., 578 Madison Ave., New York, N. Y., and (for mail), 80 N. Pleasant SL, Holyoke, Mass. COLCLOUGH, O. T. (A 1933), Custodian, . American Legation, American Government Bldg., and (for mail), 407 Elgin St., Ottawa, Ont., Canada. (for mail), Hunter-Prell Co., 38 S. Madison St., and R. F. D. No. 1, Battle Creek, Mich. COLE, Edwin Q. (Af 1931), 382 Lebanon St.. Melrose, Mass. CHRISTIE, Alfred Y. {A 1933), Salesman, U. S. Radiator Corp., 233 Vassar St., Cambridge, and COLE, Grant E. (A 1925), Vice-Pres. (for mail), Trane Co. of Canada, Ltd., 439 King St. W., (for mail), 715 La Grange St., West Roxbury, Mass. . CHRISTMAN, William F. (A 1932: J 1931), Air Cond. Engr. (for mail), Kroeschell Engrg. Co., Toronto, and Dixie, Ont., Canada. COLEMAN, John B. (Af 1920), Chief Engr. (for mail), Grinnell Co., Inc., 275 W. Exchange St., and 237 Cole Ave., Providence, R. I. . 2306 N. Knox Ave., and 2803 Lunt Ave.. Chicago, 111. CHRISTOPHERSEN, Andrew E. (Af 1935). - Engr., Custodian Board of Education (for mail), Chicago Public Schools, 226 W. Goethe St., and 2923 N. Kilpatrick Ave., Chicago, 111. CHROUCH, Richard B. (S 1935). 225 S. Butler Blvd., Lansing, Mich. . COLLIER, William I. (Af 1921). W. I. Collier & Co., 522 Park Ave., Baltimore, Md. - COLLINS, John F. S., Jr. (Af 1933), Supervisor of Steam Utilization (for mail), Allegheny . County Steam Heating Co., Philadelphia Co. Bldg., 435 Sixth Ave., and 827 N. Euclid Ave., Pittsburgh, Pa. ., COLLINS, Max D. (S 1935), Mech. Engr., 418 CHURCH, Herbert John (Af 1922), Mgr. (for Concord St., St. Paul, Minn. mail). Darling Brothers, Ltd., Room 904, 137 COMPTON, Warren E. (S 1935), 904 W. Green Wellington St. W., Toronto, and 358 Main St. N.f St., Urbana, 111. Weston, Ont., Canada. COMSTOCK, Glen Moore (A 1926), Dist. Repr., CLARE, Fulton W. (M 1927), Owner (for mail), Clare & Co., 120 Spring N.W., and 935 Plymouth L. J. Wing Mfg. Co., Osbotn Tramrail Systems (for mail), 604 Chamber of Commerce Bldg., Road, Atlanta, Ga. Pittsburgh, and 154 College Ave., Beaver, Pa. CLARKE, Samuel S. (Life Member; Af 1909), Pres, and Mgr. (for mail), S. S. Clarke & Co.,' Ltd., 605 W. Second St., and 603 W. Second St., Calgary, Alta, Canada. -CONATY, Bernard M. (Af 1935), Sales Mgr. (for mail); American District Steam Co., N. Tona- wanda, and 177 Sanders Road, Buffalo, N. Y. CONNELL, Harold (Af 1935), Engr. and Esti- CLARKSON, Robert C.t Jr. (Af 1921), 6050 Overbrook Ave., Philadelphia, Pa. . CLARKSON, W. B. (Life Member; M 1919), 251 - Broadway, Owatonnai Minn. CLAY, Charles H. (S 1935). Mech. Engr., 815 Main St., Cedar Falls, Iowa. - mator (for mail), Norair Engrg. Corp., 45 Clinton St., Newark, and 480 Waverly Place, Orange. N. J. CONNELL, Richard F. (Af 1916), Mgr., Capitol Testing Lab. (for mail). U. S. Radiator Corp., ' 1056 First National. Bank Bldg., and 2970 Bur . lingame, Detroit, Mich. . 13 American Society of Heating and Ventilating Engineers Guide, 1936 'CONNER, Raymond M. (Af 1931), Director (for mail). American Gas Association Testing Laboratories. 1032 East 62nd St.. Cleveland, and 271 East 216th St., Euclid, Ohio. CONRAD, Roy (Af 1935), Air Cond. Sales Engr.. Kelvinator Corp., 14250 Plymouth Road, and (for mail), 13153 Stoepel, Detroit, Mich. ' CONSTANT, Earl S. (7 1935), Asst.. Design Engrg. Dept.. Oklahoma Gas & Electric Co., 321 N. Harvey Ave., and (for mail), 1021 Northwest 17th St., Oklahoma City, Okla. COOK, Alton B. (S 1934), 533 S. Flood, Norman, Okla. ,. ,, COOK, Benjamin F. (Af 1920). Consulting Engr. (for mail), 114 W. Tenth St. Bldg., Kansas City, and 1720 Overton Ave., Independence, Mo. COOK, Harris R. (A 1935), Dist. Mgr. (for mail). American Foundry & Furnace Co.. 2218 N. Third St., and 2325 North 50th St., Milwaukee, Wis. COOK, Howard A. {.A 1933), Supt., Htg., Vtg. and Sprinkling, University Plbg. & Htg. Co., 3939 University Way, and (for mail).. 1433--33rd Ave., Seattle. Wash. COOK, Ralph P. (Af 1930). Engr. of Mech. Equip, (for mail), Eastman Kodak Co., Kodak Park, and 105 Falleson Road, Rochester, N. Y. COOMBE, James (A 1932), Vice-Pres. (for mail). The Wm. Powell Co., 2525 Spring Grove Ave., and 2363 Grandin Road, Cincinnati, Ohio. COON, Thurlow E. (Af 1916), Pres, (for mail). The Coon-De Visser Co., 2051 W. Lafayette, and 826 Edison Ave.. Detroit, Micb. COOPER, Albert W. (Af 1935) Branch Mgr. (for mail), Johnson Service Co., 153 West Ave. 34, Los Angeles, and 908 W. Burchett St., Glendale, Calif. ,,, ,, COOPER, Frederick D. (A 1930). Sales Engr., R. L. Deppman Co., 905 Holden Ave., and (for mail), 2918 Taylor Ave., Detroit, Mich. COOPER, John W. (Af 1932; A 1925; 7 1921), Repr. (for mail), Buffalo Forge Co.; 1596 Arcade Bldg., St. Louis, and 312 E. Big Bend Road, Webster Groves, Mo. COPPERUD, Edmund R. (7 1933), Asst. Mgr. (for mail), Minneapolis Plbg. Co., 1420 Nicollet Ave., and 4110 Nicollet Ave., Minneapolis, Minn. CORNELL, J. Clarence (A 1930), Checker (Mechanical), 12 South 12th St., and (for mail), 2823 W. Allegheny Ave., Philadelphia, Pa. CORNWALL, Charles C. (7 1935), Engrg. Dept., The Bahnson Co., and (for mail), 473 Carolina Circle, Winston-Salem, N. C. CORNWALL, George T. (Af 1919), Mgr., Boiler Dept, (for mail), Hitchings & Co., 701 Spring St., and 633 Madison Ave., Elizabeth, N. J. CORRAO, Joseph (7 1933). Engr., 854-31st Ave., San Francisco. Calif. CORRIGAN, James A. (7 1935; 5 1930), Engr. (for mail), Corrigan Co., 2501 St. Louis Ave., and 6130 McPherson, St. Louis, Mb. COTTER, Robert P. (S 1935), Junior Frigidaire Air Cond. Engr., Straus-Frank Co., 301 S. Flores St., and (for mail), 935 W. Summit Ave., San Antonio, Texas. COWARD, Charles W. (Af 1935), Pres, (for mail). Coward Engrg. Co., 413 Cooper SL, and 3168 Merriel Ave., Camden, N. J. COWARD, Herbert (Af 1921), Carrier Engrg. Corp., 604 Washington Bldg., Washington, D. C. COX, Harrison F. (A 1930), 243 Carroll St., Paterson, N. J. COX, William W. (Af 1923), Pres; and Mgr. (for mail). Heating Service Co., 326 Columbia St., and 6232-31st Ave. N.E., Seattle, Wash. CRANSTON, William E., Jr. (Af 1931). Vice- Pres. (for mail), Thermador Electrical Mfg. Co., 116 Llewellyn St., Los Angeles, and 1912 Meri dian Ave., South Pasadena, Calif. CRAWFORD, John H., Jr. (7 1930). 289 Rey nolds Terrace, Orange, N. J. GRESSY, Ralph E. (7 1929), Sales Engr., Hoffman . Specialty Co., 500 Fifth Ave., New York, and (for mail), 408 St. Lawrence Ave., Buffalo,-N. Y. CRIQUI, Albert A.* (Af 1919), Chief Engr., Htg. and Vtg. Dept., Buffalo Forge Co., 490 Broad way. and (for mail), 250 Blaine Ave., Buffalo, N. Y. CRONE, Charles B., Jr. (Af 1922). Secy-Treas. (for mail). Wendt & Crone Co., 2124 Southport Ave., and 1320 N. State St., Chicago, 111. CRONE, Thomas E. {Life Member; M 1920), Salesman, W. A. Russell & Co., Grand Central Terminal Bldg., and (for mail). Apt. 4-D, 390 Wadsworth Ave., New York, N. Y. CROSS, Robert E. (A 1931), 95 State St.. Spring field, Mass. CUCCI, Victor J. (Af 1930), Consulting Engr. (for mail), 347 Madison Ave., New York, and 451 55th St., Brooklyn, N. Y. CULBERT, William P. (A 1929), Secy, (for mail), Culbert-Whitby Co., Inc., 2019 Rittenhouse St., Philadelphia, and 929 Alexander Ave., Drexel Hill. Pa. CUMMING, Robert W. (Af 1928), Mech. and Sales Engr., Sarco Co., Inc., 183 Madison Ave., New York, and (for mail), 81 Alkamont Ave., Scarsdale, N. Y. CUMMINGS, Carl H. (A 1927; 7 1926). Mgr. (for mail). Industrial Appliance Co. of New England, 250 Stuart St., Boston, and 41 Edgehill Road, Chestnut Hill, Mass. CUMMINGS. G. J. (Af 1923), Mgr. (for mail). The Scott Co., 113 Tenth St., and 2001 Hoover Ave., Oakland, Calif. CUMMINS, George H. (Af 1919), Dist. Mgr. (for mail), Aeronn Corp., 616 United Artist's Bldg., and 17376 Wisconsin Ave., Detroit, Mich. CUNNINGHAM, John S. (S 1935), Research Asst., University of Illinois, 1108 W. Stoughton St., Urbana. 111. CUNNINGHAM, Thomas M. (Af 1931; A 1931; 7 1930), Production Mgr., Carrier Engrg. Corp., 180 N. Michigan Ave., Chicago, IU, CURRIE, Francis J. (A 1935), Prop., Htg. & Plbg. Contractor. 9 Montrose Ave., Kirklyn, Upper Darby, Pa. CURRIER. Charles H. (Af 1919), Vice-Pres. (for mail), Ross Heater & Mfg. Co., Inc., 1407 west Ave., and Park Lane Apts. 33, Gates Circle, Buffalo, N. Y. CURTIS, Herbert F. (A 1934), Berea, Ohio. CUSHMAN, Lester D. (Af 1930), 89 Traincroft St., Medford, Mass. CUTLER, Joseph A. (Af 1916), (Council. 1917 1926). Vice-Pres. (for mail). Johnson Service Co., 1355 Washington Blvd., Chicago, and 649 Hinman Ave., Evanston, 111. D DAHLSTROM, Godfrey A. (A 1927). Htg. Sales Engr., Central Supply Co., 312 S. Third St., and (for mail), 3721-47th Ave. S., Minneapolis, Minn. DAILEY, James A. (A 1920), 31-64-30th St.. Astoria, L. I., N. Y. DAKIN. Harold W. (7 1934). Instructor, 127tb Co., CCC, Pittsfield, and (for mail), 169 Park Ave., Dalton. Mass. DALLAVALLE, J. M. (7 1933), Asst. Sanitary Engr. (for mail), U. S. Public Health Service, 19th and Constitution Ave., Washington, D. C., and 17 Jones Bridge Road. Chevy Chase, Md. DALY, Charles P. (A 1935), Member of Firm (for mail), Rautman Plbg. & Htg. Co., 115 Jackson St., and 2438 Queen Anne Ave., Seattle, Wash. DALY, Robert E. (Af 1931). Executive Dept, (for mail), American Radiator Co., 40 West 40th St., and 12 East 88th St.. New York, N. Y. DAMBLY, A. Ernest (Af 1924; 7 1921), (for mail), H. B. Hackett, 901 Architects Bldg., Phila delphia, Pa., and Harvey Cedars, N. J. DANFORTH, N. Loring (Af 1919), (for mail), John W. Danforth Co., 72 EUicott St., and 129 Windsor Ave., Buffalo, N. Y. DANIELSON, Wilmot A. (Af 1935), LieutenantColonel, Quartermaster Corps, U. S. Army, Room 2236 Munitions Bldg., and (for mail), 3812 Fulton St. N.W., Washington, D. C. 14 Roll of Membership DARBY, Marion H. (J 1930). Sales Engr. (for mail), Carrier Brunswick de Mexico, S. A. Edinco Cidosa Despacho 101, Uruguay 5, Mexico D. F., Mexico. DARLING, Arthur B. (A 1929), Asst. Sales Mgr. (for mail). Darling Bros.. Ltd., 140 Prince St., Montreal P2, and 4216 Dorchester St. W., Westmount P2, Canada. DARLINGTON, Allan P. (Af 1930), Salesman (for mail), American Blower Corp., 2539 Wood ward Ave., and 3605 Devonshire, Detroit, Mich. DARTS, John A. (A# 1919), Kewanee Boiler Co., Inc., 570 Seventh Ave., New York, N. Y. DAUCH, Emil O. (Af 1921), Secy-Treas. (for mail). McCormick Plbg. Supply Co., 1675 Bagley Ave., and The Whittier Hotel, Detroit, Mich. DAVENPORT, R. F. (A 1933). Furnace Sales Mgr., Canada Foundries & Forgings, Ltd., and (for mail), 77 James St. E., Brockville, Ont., Canada. DAVIDSON, L. Clifford (Af. 1927), Associate Dist. Mgr. (for mail), Buffalo Forge Co., 220 South 16th St., and 6312 Sherwood Road, Philadelphia, Pa. DAVIDSON, Philip L. (M 1924 ; 7 1921), Asst. Dist. Mgr. (for mail). Carrier Engrg. Corp., 12 South 12th St., Philadelphia, and T4 Radnor Way, Radnor, Pa. DAVIES, George W. (Af .1918), (for mail), P. O. Box 390, Dunedin, and 145 Kenmure Road, Mornington, New Zealand. . DAVIS, Arthur C.* (Af 1920), Supt. of Main tenance, The Port of New York Authority, 111 Eighth Ave., New York, N. Y., and (for mail), 73 Preston St., Ridgefield Park, N. J. DAVIS, Arthur F. (Af 1934), Vice-Pres. (for mail). The Johnson & Davis Plbg. & Htg. Co., 2235 Arapahoe St., and 1901 Ivanhoe St., Denver, Colo. DAVIS, Bert C. (Af 1904), (Council, 1917). Pres, and Treas. (for mail), American Warming & Ventilating Co., 317-19 Pennsylvania Ave., and 603 W. Church St., Elmira, N. Y. DAVIS, Calvin R. (Af 1927) Branch Mgr. (for mail), Johnson Service Co., 2328 Locust St., and 7534 Westmoreland Drive., St. Louis, Mo. DAVIS, James R. (S 1934), 2111 Abington Road, and (for mail), 9704 Miles Ave., Cleveland, Ohio. DAVIS, Joseph (Af 1927; A 1926), Htg. and Vtg. Contractor (for mail), 607 Root Bldg., 70 W. Chippewa St., and 166 Huntington Ave., Buffalo, N. Y. DAVIS, Otis E. (Af 1929; A 1925), Sales Engr. (for mail), Hoffman Specialty Co., Waterbury, Conn., and Box 98, Scottsbluff, Nebr. ` DAVIS, Rowland G. (A 1921), Sales Repr., 887 Nela View Road, Cleveland Heights, Ohio. DAVISON, Robert L. (Af 1934), Director of Research (for mail), John B. Pierce Foundation, 40 West 40th St., New York, N. Y. DAWSON, Eugene F. (Af 1934). Asst. Prof., Mech. Engr. (for mail). University of Oklahoma, and 916 S. Flood St., Norman, Okla. DAWSON, G. Stewart (A 1935), Mdse. Sales Engr. (for mail), B. C. Electric Railway Co., Ltd., 425 Carrall St., and 1860 Barclay St., Vancouver, B. C., Canada: DAWSON, Thomas L. (Af 1930), Pres, (for mail). Thomas L. Dawson Co., 2035 Washington St., Kansas City, Mo., and 56th and Shawnee Mission Road, Rosedale Sta., Kansqg City, Kan. DAY, Harold C. (A 1934), Mgr. (for mail), American Radiator Co., 374 Delaware Ave., and Stuyvesant Hotel, Buffalo. N. Y. DAY, V. S.* (Af 1924), Engr. (for mail). Carrier Engrg. Corp., 850 Frelinghuysen Ave., Newark, and 160 Summit Ave., Summit, N. J. DEAN, Charles L. (Af 1932). Asst. Prof.. Mech Engrg., University of Wisconsin, 305 University Extension Bldg., and (for mail), 102 Grand Ave., Madison, Wis. DEAN, Frank J., Jr. (7 1935: S 1934), Sales Engr., Gustin Bacon Mfg. Co., and (for mail), 201 West 51st St. Terrace, Kansas City, Mo. DeBLOIS, Lewis A. (Af 1934), Consulting Engr., 245 East 21st St., New York, N. Y. DeBOOS, F. A. (Af 1935), Dist. Mgr., B. F. Sturtevant Co., 812 Michigan Theatre Bldg., and (for mail), 1083 Field Ave., Detroit, Mich. DEELY, James J. (7 1933), House Htg. Sales Engr., Brooklyn Union Gas Co., 180 Remsen St., and (for mail). Hotel St. George, Brooklyn, N. Y. DeLAND, Charles W. (Af 1924; 7 1923), SecyTreas. (for mail), C. W. Johnson Co., Inc., 211 N. Desplaines St., and 2021 Estes Ave., Chicago, 111. DENISE, John R. (7 1935), Asst. Commercial Engr., Consolidated Gas Co. of New York, 4 Irving Place, and (for mail), 230 Madison Ave., New York, N. Y. DENNY, Harold R. (A 1934), Mgr., Merch, Dept., American Blower Corp., 401 Broadway, New York. N. Y. DEVER, Henry F. (A 1935), Sales Engr. Minne apolis-Honeywe11 Regulator Co., Wayne and Robert Sts., Philadelphia, Pa. DEWEY, Ritchie P. (Af 1934). Chief Engr., Barber-Colman Co*, and (for mail), 2301 Oxford St.. Rockford. IU. DIBBLE, S. E.* (Af 1917), (Presidential Member), (Pres., 1925; 1st Vice-Pres., 1924; 2nd VicePres., 1922; Council. 1921-1926), Supt., Thomas Ranken Patton School, Elizabethtown, Pa. DICK, Andrew V. (71935), Sales Engr., VandecarHarmon Co., Albany, and (for mail), 1006 Albany St.. Schenectady, N. Y. DICKENSON, Frederick R. (A 1934), Dist. Mgr. (for mail), American Blower Corp., 1302 Swetland Bldg., Cleveland, and 3435 Menlo Road, Shaker Heights, Ohio. DICKEY, Arthur J. (Af 1921), Vice-Pres. and Gen. Mgr., C. A. Dunham Co., Ltd., 1523 Davenport Road, and (for mail), 9 Mossora Place, Toronto, Ont., Canada. DICKSON, Robert B. (Af 1919), Pres, (for mail). Kewanee Boiler Corp., Franklin St. and C. B. & Q. Tracks, and 409 E. Prospect St.. Kewanee, 111. DTMOR, Elton J. (Af 1933). Br. Mgr. and Engr., The Trane Co., Box 1271, Memphis, Tenn. DISNEY, Melvin A. (A 1934). Co-Partner, Disney-Leffel Co., 4301$-$ Main St., and (for mail), 5435 Holmes. Kansas City. Mo. DISTEL, Frank (Af 1918), Owner, Distel. Heating Equip. Co., 404-6 Kalamazoo Plaza, and (for mail), P. O. Box 133, and 1011 W. Genesee St., Lansing, Mich. DIVER, M. L. (Af 1925), Consulting Engr., P. O. Box 1016, San Antonio, Texas. DIXON, Arthur G. (Af 1928), Sales Mgr. (for mail), Modine Mfg. Co., and 442 Wolff St., Racine, Wis. DOBBS, C. E. (A 1921), Repr., Burnham Boiler Corp., 31st and Jefferson Sts., Philadelphia, Pa., and (for mail), 72 Berlin Ave., Haddonfield, N. J. DODDS, Forrest F. (Af 1920), Branch Mgr. (for mail), American Radiator Co., 1023 Grand Ave., and Riviera Apts. 229, Ward Pkwy., Kansas City, Mo. DODGE, Harry A. (Af 1935), Elec. Engr., S. SJ. Kress & Co., 114 Fifth Ave., and (for mail), 425 East 80th St., New York, N. Y. DODGE, Harry G. (A 1934), Vice-Pres., Metro politan Pipe & Supply Co., 145 Broadway, Cambridge, and (for mail), 28 Rustic Road, Melrose Heights, Mass. DOERING, Frank L. (Af 1919), Salesman, American Radiator Co., Richmond, and (for mail). 238 Boston Ave., Lynchburg, Va. DOHERTY. Russell (A 1929), Dist. Mgr. (for mail), National Radiator Corp., 1111 East 83rd St., Chicago, and 300 Forest Ave., Oak Park, 111. DOLAN, Raymond G. (Af 1926; A 1926; 71922), Secy-Treas. (for mail), Tom Dolan Htg. Co., Inc., 614 W. Grand, and 2112 West 20th. Oklahoma City, Okla. DONNELLY, James A.* (Af 1904), (Treasurer. 1912-1914), Largent, W. Va. DONNELLY, Russell (Af 1923), Sales Engr. (for mail), Nash Engrg. Co., Graybar Bldg., 420 Lexington Ave., New York, N. Y. 15 American Society of Heating and Ventilating Engineers Guide, 1936 DONOHOE, John B. (J 1935), Engr. and Est. (for mail), B. F. Donohoe Co., 51 Albany St., Boston, and 24 Primrose St., RosUndale. Mass. DONOVAN, William J. (A 1930), 2239 North 27th St., Philadelphia, Pa. DONZELLI, Enrico (M 1933), Piazza S.S. Pietro e Lino No. 4, Milan, Italy. DORFAN, M. I. (Af 1929), Mgr., Dust Collecting Div., Blaw-Knox Co., P. O. Box 119S, and (for mail), 6357 Morrowfield Ave., Pittsburgh, Pa. DORNHEIM, G. A. (Af 1912; J 1906), 15 Hamil ton Ave., Bronxville, N, Y. ' DORSEY, Francis C. (Af 1920). Engr. and Contr. (for mail), Francis C. Dorsey, Inc., 4520 Schenley Road, Roland Park, and 212 Gittings Ave., Baltimore, Md. DOSTER, Alexis (A 1934), Secy, (for mail), The Torrington Mfg. Co., 70 Franklin St., Torrington, and Litchfield. Conn. DOUGHTY, Charles John (Af 1925). Pres, and Managing Director (for mail), C. J. Doughty & Co., Fed. Inc., U. S. A., 30 Brenan Road, and 1920 Ave. Joffre, Shanghai, China. DOVOLIS, Nick J. (S 1935), 3403 Chicago Ave., Minneapolis, Minn. DOWNE, Edward R. (Af 1927), Vice-Pres., American Gas Products Corp- 40 West 40th St., New York, and (for mail), 108 Park Ave., Larchmont, N. Y. DOWNE, Henry S. (.Life Member; M 1895). Cie Nationale des Radiateurs, 149 Boulevard Haussman, Paris, France. DOWNES, Henry H. (Af 1923), Mgr., Navy . Equip. Div. (for mail), American Blower Corp., ` .438 Woodward Bldg., Washington, D. C., and 4621 Chevy Chase Blvd,, Chevy Chase, Md. DOWNES, Nate W. (Af 1917), (Council, 1928 1930), Chief Engr. and Supt. of Bldgs, (for mail). School Dist. of Kansas City, Mo., 317 Finance ' Bldg., and 2119 East 68th St- Kansas City, Mo. DOWNS, Sewell H. (Af 1931), Chief Engr., Clarage Fan Co., and (for mail), 211 Creston Ave., Kalamazoo, Mich. DOYLE, William J. (M 1920), Factory Mgr., The Williamson Heater Co., 4558 Marburg Ave., and (for mail), 3766 Hyde Park Ave., Cincinnati, Ohio. DRINKER, Philip* (M 1922). Assoc. Prof, (for mail). Harvard School of Public Health, 55,, Shattuck St., Boston, and Pudding Stone Lane. Newton Centre, Mass. DRISCOLL, William H.* (Af 1904), (Presi dential Member), (Pres., 1926; 1st Vice-Pres., 1925; 2nd Vice-Pres., 1924; Treas- 1923; Council, 1918-1927), (for mail), Thompson-Starrett Co., Inc., 444 Madison Ave., New York, N. Y., and 50 Glenwood Ave., Jersey City, N. J. DuBOIS, Louis J. (M 1931), Air Cond. Engr., York Ice Machinery Corp., 117 South 11th St- St. Louis, and (for mail), 7451 Bland Drive, Clayton. Mo. DUBRY, Ernest E. (M 1924), Asst. Supt., Central Htg- The Detroit Edison Co., 2000 Second Aveand (for mail), 9116 Dexter Blvd- Detroit, Mich. DUDLEY, William L. (M 1922), Vice-Pres. (for mail). Western Blower Co- 1800 Airport Way, and 814--32nd Ave- Seattle, Wash. DUFF, Kennedy (Af 1915), Mgr. (for mail), Johnson Service Co- 28 East 29th St- New York, N. Y- and 9 Park Ave- Maplewood, N. J. DUGAN, Thomas M. (M 1920), Sanitary and Htg. Engr., National Tube Co- Fourth Ave. and Locust Si- and (for mail), 1308 Freemont St- McKeesport, Pa. . DUGGER, Earl R. (5 1934), Service and Instal lation Engr- Oklahoma Refrigerating Co- 18 W. ' Grand, and (for mail), 3409 Classen Blvd- Oklahoma City, Okla. DUNCAN, James R. (M 1923). Chief EngrCarrier Australasia, Ltd., 56 Hunter St- Sydney W CW DUNCAN, William A. (A 1930), Dist. Service Engr. (for mail). Dominion Oxygen Co- Ltd92 Adelaide St. W- and 20 TyreU Ave., Toronto, Ont- Canada. DUNHAM, Clayton A* (M 1911), Pres, (for mail), C. A. Dunham Co- 450 E. Ohio St- Chicago, and 150 Maple Hill Road, Glencoe, IU. DURKEE, Merritt E. (A 1930), Sales Engr. (for mail), C. A. Dunham Co., 101 Park Ave- New York, and 254 Marline Ave- White Plains, N. Y. DURNING, Edward H. (J 1931), Commercial Sales, Dallas Gas Co- Harwood and Jackson Sts- and (for mail), 1830 Moser St- Dallas, Texas. DUSOSSOIT, Edmond A. (M 1920), Treas. (for mail). Lynch & Woodward, Inc- 320 Dover St- Boston, and 16 Hancock Ave- Newton Centre, Mass. ' DWYER, Thomas F. (M 1923), Mech. Engr. (for mail). Board of Education, 49 Flatbush Ave. Ext- Brooklyn, and 1163 Clay Ave., New York, N. Y. - DYER, Orville K. (M 1919), Mgr- Blower Div. - (for mail), Buffalo Forge Co- 490 Broadway, and 11 Russell Ave- Buffalo, N. Y. E EADE, Hugh R. (Af 1935). Archt. (for mail), 5 Imperial Bank Bldg- and Cheriton Ave- N. Kildonan, Winnipeg, Canada. EADIE, John G. (M 1909), Eadie, Freund & Campbell Co., 110 West 40th St., New York, N. Y. EAGAR, R. Frank (Af 1922), 93 Edward St- Halifax, N. S- Canada. EARLEY, Thomas J. (A 1935), Sales Engr- Jennison Co., 17 Putnam St- and (for mail), 46 Elizabeth St., Fitchburg, Mass. EASTMAN, Carl B. (M 1932; A 1932; J 1929), Mgr- Philadelphia Sales Office, C. A. Dunham Co- 1500 Walnut St., Philadelphia, and (for mail), 530 Brookview Lane, Brookline, Upper Darby, Pa. EASTWOOD, E. O. (Af 1921), (Council, 1931 1934), Prof, of Mech. Engrg. (for mail). Uni versity of Washington, and 4702-12th Ave. N.E., Seattle, Wash. EATON, Byron K. (Af 1920), Regional Sales Mgr- Delco Appliance Corp- Rochester, N. Y- and v (for mail), 75 N. Park Road, LaGrange, IU. EATON, William G. M. (A 1934), Sales Engr., Pease Foundry Co- Ltd- 227 Victoria St- Toronto 2, and (for maU), 59 Symington Ave- Toronto 9, Ont., Canada. EBERT, William A. (Af 1920), Mech. Contractor (for mail), 1026 W. Ashby, and 2151 W. Kings Highway, San Antonio, Texas. ECKERT, E. Kendall (J 1935), Engr. and Sales (for mail), Holland Furnace Co- 212 E. Wash ington, Ann Arbor, and South Haven, Mich. EDELMAN, Bernard P. (A 1935), Sales Dept., U. S. Air Cond. Corp- and (for mail), 4233 Nicollet Ave., MinneapoUs, Minn. EDWARDS, Daniel F. (Af 1920), 2340-42 Pine St- St. Louis, Mo. EDWARDS, Don J. (A 1933), Vice-Pres. (for mail). General Heat & Appliance Co- 698 Beacon St., Boston, and 40 Rockledge Road, Newton, Mass. , EDWARDS, Henry B. (J 1935), Engr. (for mail), . Carrier Engrg. Corp- 748 E. Washington Blvd., and 701 S. Grammercy Drive, Los Angeles, Calif. EDWARDS, Paul A. (Af 1919), Pres, (for mail).. The G. F. Higgins Co- 60S Wabash Bldg- and 3074 Pinehurst Ave., Pittsburgh, Pa. EELLS, Henry B. (Af 1926), New York Mgr- Baraes & Jones, Inc., 101 Park Ave- New York, and (for maU), 1049 East 27th St- Brooklyn, N. Y. EGGLESTON, Lewis W. (Af 1921), American Radiator Co- 5961 Lincoln Ave- Detroit, Mich. EGGLY, Harry J., Jr. (Af 1933), Consulting Engr. (for mall), 1805 Walnut St- Philadelphia, . and Elkins Park Apts., Elkins Park, Pa. ' EHRLICH, M. William* (Af 1916). Chief Engr- Commodore Heaters Corp- 11 West 42nd St- New York, N. Y- and (for mail), 56 Ridge Road, Lyndhurst, N. J. 16 Roll of Membership E1CHER, HuBert C. (Af 1922), State Director. School Bldgs. Div- Dept, of Public Instruction, State Capitol, and (for mail), 103 South StHarrisburg, Pa. EISS, Robert M. (Af 1933; A 1933; J 1930), Engr., Kimberly, Clark Corp- and (for mail), 216 N. Commercial St- Neenab, Wis. ELLINGWOOD, Elliott L. (M 1909), 354 S. Spring St- Los Angeles, Calif. . ELLIOT, Edwin (Af 1929), (for mail), Edwin EUiot & Co., 560 North 16th St- Philadelphia, Pa- and 403 W. Price St- Germantown, Phila delphia, Pa. ELLIOTT, Louis (Af 1932), Consulting Mech. Engr- Room 1914, Electric Bond & Share Co2 Rector St- New York, N. Y. ELLIOTT, Norton B. (A 1934). Branch MgrAmerican Blower Corp- 1011 Majestic Bldg-and (for mail), 5170 N. Idlewild Ave- MUwaukee, Wis. ELLIS, Ernest E. (Af 1922), Secy-Treas- F. A. Ellis & Co., Inc., 840 Center St- Winnetka, IU. ELLIS, Frederick E. (Af 1923), Sales Mgr. (for mail). Imperial Iron Corp- Ltd- 30 Jefferson Ave- Toronto, and 9 Princeton Road, Kingsway, P. O. Toronto 3, Ont., Canada. ELLIS, Frederick R. (M 1913). Sales EngrBuerkel & Co- Inc- 18-24 Union Park StBoston, and (for mail), 131 Beacon St- Hyde ELLIsi Gershom P. (Af 1935), Chief Engr. (for maU), Board of Public Education, 341 Bellefield Ave- and 6601 DalzeU Place, Pittsburgh, Pa. ELLIS, Harry W. (Af 1923; A 1909), Pres- Johnson Service Co- 507 E. Michigan StMilwaukee, Wis. EMERSON, Ralph R. (Af 1922), Pres., Emerson Swan Goodyear Co., 110 Arlington St- Boston, and (for mail), 44 Whitney Road, NewtonviUe, Mass. EMERY, Gordon W. (A 1935). Service EngrH. H. Van Sann, inc- 190 Moore St- Hacken sack, and (for mail), 65 Birk St- RocheUe Park, N. J. EMMERT, Luther D. (Af 1919), Repr. (for maU), Buffalo Forge Co- Room 1909, 20 N. Wacker Drive, Chicago, and 1704 Hinman Ave., Evans ton. 111. EMMONS, Neal L. (S 1934), 1100 East 19th, Oklahoma City, Okla. ENGEL, Edward (J 1933), Chief Engrg. Drafts man (for mail), Hull Div- U. S. Navy Yard, and 2608 North 30th St- Philadelphia, Pa. ENGLE, Alfred (A 1923), Sales Mgr. (for mail), Jenkins Bros- 80 .White St- New York, and 1 Edgewood Road, Scarsdale, N. Y. ENGLISH, Harrold (A 1930; Af 1935), Pres, (for mail), English & Lauer, Inc., 309 West 12th St and 201 S. Irving Blvd- Los Angeles, Calif. ENSIGN, Willis A. (Af 1935), Vice-Pres- Frontier Engrg. Corp., 972 Ellicott Square Bldg- Buffalo, and (for mail), Derby, N. Y. EPPLE, Arnet B. (J 1934), B.'F. Sturtevant CoHyde Park, Boston, and (for mail), 8 Elm StHyde Park, Mass. EPPR1GHT, John O. (J 1934), 101 East 40th StKansas City, Mo. ERDLE, Gardner F. (A 1933), Mfrs. Repr. (for mail), 374 Delaware Ave- Buffalo, and 19 Tremont Ave- Kenmore, N. Y. ERICKSON, Harry H. (A 1929), Dist. Mgr. (for mail). General Fittings Co- Architects Bldg- and 217 W. Tulpehocken St- Philadelphia, Pa. ERICKSON, Martin E. (A 1926), Supt- Main tenance, Board of Education, and (for mail), 1533 South 74th St- West Allis. Wis. ERICSSON, Eric B. (Af 1933), Engr- Custodian, . . Board of Education, and (for mail), 605 West 116th St- Chicago, 111. ESCHENBACH, Sam P. (J 1935), Salesman (for mail), American Blower Corp- 822 White BldgBuffalo, and 269 Wardman Road, Kenmore, N. Y. EVANS, C. A. (Af 1919), 527 Massachusetts Ave Buffalo, N. Y. EVANS, Edwin C. (Af 1919), Consulting Engr-- 2953 Zephyr Ave- Corliss Sta. P. O- Pittsburgh. Pa. . EVELETH, Charles F.* (Af 1911), 2030 East 115th St- Cleveland, Ohio. EVEREST, R. Harry (Af 1935), Sheldons, LtdGait, and (for mail), 235 Waterloo St., Preston. Ont- Canada. EVERETTS, John. Jr. (A 1935; J 1929), Engr. (for mail), W. L. Fleisher, 11 West 42nd St- New York, and 83 Kenilworth Place, Brooklyn, N. Y. EVLETH, Everett B. (A 1927), Division Mgr. (for mail), Minneapolis-Honeywell Regulator Co43 E. Ohio St- Chicago, and 1023 Ashland Ave., Wilmette, 111. F FABER, Dr. Oscar (Af 1934), Consulting Engr. (for mail), Romney House, Marsham StWestminster, London, England. FAGIN, Daniel J. (Af 1932), Htg. Engr., House Htg. Div., Laclede Gas Light Co- 1017 Aline St and (for mail), 4920 Chippewa Ave., St. Louis, Mo. FAHNESTOCK, Maurice K* (Af 1927), Research Asst. Prof, (for mail). University of Illinois, 214 M. E. Laboratory, and 701 W. California StUrbana, III. FAILE, Edward H. (Af 1934), Desig. and Const. Engr. (for mail), 608 Fifth Ave., New YorkN. Y- and R. F. D. No. 1, Westport, Conn. FALTENBACHER, Harry J. (Af 1930), PresH. J. Faltenbacher, Inc- 235 E. Wister StPhiladelphia, Pa. FALVEY, John D. (Af 1922), Consulting Engr., 316 N. Eighth St- St. Louis, and (for mail), 6636 Pershing Ave- University City, Mo. FAMILETTI, A. Robert (/ 1930), Asst. Engrg- Draftsman Industrial Dept- Philadelphia Navy Yard, and (for mail), 6735 Guyer Ave- Phila delphia, Pa. . FANSLER, P. E. (A 1927), Editor (for mail). Oil Heat, 167 Madison Ave., New York, N. Y- and Catonsville, Md. FARBMAN, Leonard X. (J 1935), Assoc. Engr. (for mail), M. Farbman, 331 West 59th St- and 817 West End Ave- New York, N. Y. ' FARBMAN, Saul M. (5 1935), 817 West End Ave- New York, N. Y- and (for mail), 5227 Fifth Ave- Pittsburgh, Pa. FARLEY, W. F. (Af 1930), Salesman, American Radiator Co- 40 West 40th St- New York, and (for mail), 28 Elm St- New Rochelle, N. Y. FARLEY, Willoughby S. (J 1933), Partner, Farley & Luther, 120 S. Union St- and (for mail), 211 Montague St- Danville, Va. FARNHAM, Roswell (Af 1920), (Council. 1927- 1932), Dist. Mgr- Engrg. Sales (for mail), Buffalo Forge Co- P. O. Box 985, and 5 Claren don Place, Buffalo, N. Y. FARNSWORTH, John G. (J 1931), Gas House Htg. Engr. (for mail). Central Illinois Light Co316 S. Jefferson St- and 216.Dechman AvePeoria, 111. FARRAR, Cecil W. (Af 1920; A 1918), (Treas- 1930; Council. 1930), Pres, (for mail), Excelso. . Products Corp- 1807 Elmwood Ave- and 29 Oakland Place, Buffalo, N. Y. FATZ, Joseph L. (Af 1935), Htg. and Vtg. Engr- Board.of Education, 228 N. LaSalle St- and (for mail), 1822 N. Mason Ave- Chicago, IU. FAULKNER, Gordon (S 1935), 1116 W. CaUfornia St- Urbana, 111. FAUST, Frank H.* (J 1930), Engr. (for mail). General Electric Co- 5 Lawrence St- Bloomfield, and 202 Vreeland Ave- Nutley, N. J. ' FAY, Francis C. (Af 1925), Engr. (for maU). Raisler Heating Co- 129-31 Amsterdam Ave- New York, and 9217-54th Ave- Elmhurst, L. I- N. Y. . 17 American Society of Heating and Ventilating Engineers Guide, 1936 FEBREY, Ernest J. (M 1903), Htg. and Air Cond. (for mail). 616 New York Ave. N.W., and 2331 Cathedral Ave., Washington, D. C. FEEHAN. John B. {M 1923), Pres, and Treas. (for mail), John B. Feehan, Inc., 471 Union SL, Lynn, and 4 Ocean View Drive., Marblehead, Mass. FEELY, Frank J. {M 1935; A 1929), Mgr. of Sales, The Taylor Supply Co., 700 Monroe Ave., and (for mail), 950 Trombley Road, Grosse Pointe Park, Detroit, Mich. \ FITZSIMONS, J. Patrick (7 1934; S 1932), Air Cond. Engr. (for mail), Trane Co. of Canada, Ltd., 439 King SL W., and 646 Spadina Ave., Toronto, Ont., Canada. FLANAGAN, Edward T. (A 1929). C. A. Dunham Co., Ltd., 1139 Bay SL, Toronto, Ont., Canada. FLARSHEIM, Clarence A. (7 1933), Mgr., Air Cond Dept, (for mail), Kansas City Airtemp Corp., 2425 McGee St., and 3720 Holmes SL, Kansas City. Mo. FLE1SHER, Walter L.* {M 1914). Consulting FEHLIG, John B. {M 1918), Pres, (for mail). Engr. (for mail). 11 West 42nd SL, and 290 West Excelsior Htg. Supply Co., 528 Delaware-SL, and 2927 Brooklyn Ave., Kansas City, Mo. 11th St.. New York. N. Y. FLEMING, James P. (M 1923), Engr., Custodian FELDMAN, A. M* {Life Member; M 1903), Board of Education, 5045 N, Kimball Ave., Consulting Engr., 40 West 77th St., New York, N. Y. FELS, Arthur B. (M 1919), The Fels Co., 42 Union St., Portland, Maine. FELTWELL, Robert H. {M 1905), Htg. Engr., U. S. Radiator Corp., 2321 Fourth St. N.E., and (for mail), 1370 Oak St. N.E., Washington, D. C. FENNER, N. Paul (A 1928), John G. Kelly, Inc.. 210 East 45th SL, New York, N. Y. FENSTERMAKER, Sidney E. (M 1909), Pres, (for mail), S. E. Fenstermaker & Co., 937 Architects and Builders Bldg., and 3102 Wash ington Blvd., Indianapolis, Ind. FERGESTAD, Marvin L. (7 1935), Sales Engr. Chicago, 111. FLEMING, Thomas F. (S 1935), 7004 Eggleston Ave., Chicago, 111. FLINK, Carl H. (M 1923), Director of Research (for mail), American Gas Products Corp., 408 East 111th St.,. New York, and 74 Brookside Ave., ML Vernon, N. Y. FLINT, Coll T. (Atf 1919), N. E. Sales Mgr. (for mail). The H. B. Smith Co., 640 Main SL, Cambridge, and 56 Brantwood Road, Arlington, Mass. FLOYD, Morris {M 1933), Surface Combustion Co., and (for mail). The Phelps, 506 E. Fourth St., Cincinnati, Ohio. FOGARTY, Orville A. {M 1934), Engr., Rivers (for mail). The Insulite Co., Builders Exchange Salvage Co., Ltd., 2245 St. James St. W., Bldg. (Main FI.), and 3509 S. Colfax Ave., Montreal, and (for mail), Rigaud, P. Q., Canada. Minneapolis, Minn. FONDA, Bayard P. {M 1934), Air Cond. Engr. (for FERGUSON, Ralph R. {M 1934; A 1927; 71925). mail), Bryant Heater Co., 17825 St. Clair Ave., Mgr., Trade Dept., American Blower Corp., 401 Cleveland, and 3326 Clarendon Road, Cleveland Broadway, New York, N. Y., and (for mail), 160 Prospect SL. East Orange, N. J. Heights, Ohio. FORFAR, Donald M. {M 1917), Mech. Engr. (for FICNERSKI, Paul (S 1935). 1005 S. Fifth SL, Champaign, 111. FIELDER, Harry William (M 1923), Pres, (for mail). Air Conditioning Utilities. Inc., 489 Fifth Ave., New York, and 303 E. Fourth St., Mt. Vernon, N. Y. FIFE, G. Donald (A 1931; 7 1929), Air Cond. Engr.. G. A. Weschler, 732-17th SL N.W., and (for mail), 3221 Connecticut Ave., Washington, D. C. F1LKINS, Harry L. (A 1932), Vice-Pres., City Ice Co of K. C., 21st and Campbell Sts., and (for mail), 34 East 55th Terrace, Kansas City, Mo. FILLO, Frank B. (A 1934), Minneapolis-Honey- mail), Grinnell Co., 240 Seventh Ave. S., and 4817 Emerson Ave. S., Minneapolis, Minn. FORSBERG, William (M 1919). Hopson & Chapin Mfg. Co., 231 State St., New London, Conn. FORSYTH, Arthur T. (A 1934), Dist. Repr., Buffalo Forge Co., 2434 First Ave. S. Seattle, Wash. FOSTER, Charles (Af 1923), Consulting Engr. (for mail), 508 Sellwood Bldg., and 2831 E. First St., Duluth, Minn. FOSTER, James M. (M 1930; A 1920), Factory Repr. (for mail), 4526 Olive SL, and 7021 Lindell Ave., St. Louis, Mo. FOSTER. Tillman R. (7 1930), Carrier Engrg. weli Regulator Co.. 2831 Olive St., SL Louis, Mo. Corp., 180 N. Michigan Ave., Chicago, III. FINAN, James J. (M 1923), Supervising Engr., FOULDS. P. A. L. (M 1916), Mech. Engr. (for Board of Education, City of Chicago, 228 N. LaSalle SL. Builders Bldg., and (foT mail), 7149 mail). Office of Hollis French, Consulting Engr., 210 South SL, Boston, and 72 Whitin Ave., Euclid Ave., Chicago, 111. FINCH, Stanley B. (A 1931), Industrial Engr., Brooklyn Union Gas Co., 180 Remsea SL, Brooklyn, N. Y. FINERAN, Edward V. (7 1935), AssL Engr., Washington Gas Light Co., Washington, D. C., and (for mail), 9Q6 Thayer Ave., Silver Spring, Md. FIRESTONE, James F. (A 1925; 7 1914), Exec. Vice-Pres., Round Oak Co., and (for mail), 203 Orchard St., Dowagiac, Mich. . . FITTS, Charles D. (M 1920). Mgr. (for mail), American Radiator Co., 692 Prior Ave., St. Paul, and 2807 Dean Blvd., Minneapolis, Minn. FITTS, Joseph C. (M 1930), Secy., Heating. Piping & Air Conditioning Contractors National Association, 1250 Sixth Ave., New York, 1ST. Y., and (for mail), 215 Kenilworth Road, Ridgewood, N. J. . FITZGERALD, James F. (5 1935), 250 E. Grand Blvd., Detroit, Mich. . FITZGERALD, Matthew J. (M 1934), Treas., Standard Asbestos Mfg. Co., 820 W. Lake St., and (for mail), 1117 N. Linden Ave., Oak Park, III. . FITZGERALD, William E. (S 1935), Engr., Fitzgerald Plbg. & Htg. Co., Inc., 939 Louisiana - Ave., and (for mail), 210 Vine St., Shreveport, La. Point of Pines, Revere, Mass. FOULDS, Samuel T. N. (7 1930), Sales Engr., Power Equipment Co., 791 Tremont St., Boston, and (for mail), 72 Whitin Ave., Revere, Mass. FOWLES, Harry H. (J 1934), Htg. Engr.. Carman-Thompson Co., 12-14 Lincoln St., Lewiston, and (for mail), Y. M. C. A., Auburn, Maine. FOX, Ernest {M 1935), AssL to Engr., C. A. Dunham Co., Ltd., 1523 Davenport Road, and (for mail), 141 Westmount Ave., Toronto, OnL, Canada. FOX, John H. (M 1935), Sales Engr. (for mail), Minneapolis-Honeywell Regulator Co., Ltd.. 117 Peter SL, and 37 Macdonell Ave., Toronto, OnL, Canada. FRAMPTON, Alfred C. (S 1934), 729H Wilson, Norman, Okla. FRANK, John M. {M 1918; A 1912), Ilg Electric Vtg. Co., 2850 N. Crawford Ave., Chicago, 111. FRANK, Olive E.* (M 1919), Pres- (for mad). Frank Engrg. Co., 11 Park Place, and 610 West 110th SL, New York, N. Y. FRANKEL, Gilbert S. (M 1926). Mgr., Federal & Marine Dept, (for mail), Buffalo Forge Co., 403 Commercial National Bank Bldg., Wash ington, D. C. FRANKLIN, Ralph S. (M 1919), Prea-Treas. (for mail), Albert B. Franklin, Inc., 38 Channcy St., Boston, and 320 Grove St., Melrose, Mass. 18 Roll of Membership FREAS, Royal Bruce (M 1928), Vice-Pres. (for mail). Freas Thermo Electric Co., 1750 N. Springfield Ave., Chicago, III., and 4 West 43rd St., New York, N. Y. FREITAG, Frederic G. {M 1932), Chief Engr. (for mail), Sylvestre Oil Co., 709 S. Columbus Ave., and 145 Cottage Ave., ML Vernon, N. Y. FRENCH, Donald {M 1926), Vice-Pres. (for mail). Carrier Engrg. Corp., 850 Frelinghuysen Ave., Newark, and 45 Waldron Ave., Summit, N. J. FREY, George O. (7 1934), ConsL DepL (for mail), Warner Bros. Theatres, Inc., 321 West 44th SL. New York, and ApL C 19, 221 Linden Blvd., Brooklyn, N. Y. FRIED, Harold V. (A 1935), Air Cond. Engr. (for mail), Birmingham Electric Co., 2100 N. First Ave., and 1585 Druid Hill Drive, Birmingham, Ala FRIEDMAN, Ferdinand J* (M 1921), Mc- Dougall & Friedman, 31 Union Square, New York, N. Y., and (for mail), 1221 Osborne SL, Montreal. P. Q., Canada. FRIEDMAN, Milton (7 1935; 5 1933). 470 West End Ave., New York, N. Y. FRISSE. John L. (5 1935), 5538 Forbes St., Pittsburgh, 17, Pa. FRITZ, Charles V. (5 1933), 26 Cottage Court/ Freeport. N. Y. FRITZBERG, L. H. (7 1931), AssL Mgr., Ex tended Surface DepL (for mail), B. F. Sturtevant Co., Hyde Park, and 1338 River St., Hyde Park, Boston. Mass. FUKUI, Kunitaro (M 1926), Auditor. Air Cond., Oriental Carrier Engrg. Co., Ltd., Osaka Mitsui . Bldg., Nakanoshima, Osaka, Japan. ' GAYLOR, William S. {M 1919), Consulting Engr., Flameking Co., Inc., 2159 Madison Ave., New York, and (for mail), 42 Mayhew Ave., Larchmont, N. Y. GAYLORD, F. H. {M 1921), Western Sales Mgr. (for mail), Hoffman Specialty Co., Inc., 130 N. Wells St., Chicago, and 362 N. York SL, Elm hurst. 111. GEIGER. Irvin H. {M 1919), Reg. Prof., Engr. and Mfrs. Repr., Room 319 Telegraph Bldg., Harrisburg, Pa. GEISSBUHLER, John O. (5 1934), University Circle, and (for mail), 9820 Zimmer Ave., Cleveland. Ohio. GELB, Amlel (5 1935), 1042 Irving Ave. N., Minneapolis, Minn. GEMMILL, Robert A. (A 1935), Mgr.. Norge Oil Burner Div., Trilling & Montague, 2409 Walnut St., and (for mail), 4710 Locust St., Philadelphia, Pa. GERMAIN, Oscar (M 1935), Foreman, Germain & Frere, Ltd., 237 SL Antonie St., and (for mail), 1343 Blvd. SL Louis, Three Rivers, P. Q., Canada. GERRISH, Grenville B. (7 1930), Mgr., (for mail), Fitzgibbons Boiler Co., Inc., 80 Boylston St., Boston, and 89 Warwick Road, Melrose Highland, Mass. GERRISH, Harry E. (M 1910), (Council, 1919), Partner (for mail), Morgan-Genrish Co., 307 Essex Bldg., and 4534 Fremont St., Minneapolis, Minn. GETSCHOW, Roy M. {M 1919), Secy, (for mail), Phillips Getschow Co., 32 W. Austin Ave., and 1336 Arthur Ave., Chicago. 111. GIANNINI, Mario C. {M 1935), Faculty Lecturer, G New York University, University Heights, New GABY, Frederick A. (M 1926), Chief Engr. (for mail), Hydro-Electric Power Commission of Ontario, 190 University Ave., and 480 Spadina Road, Toronto, Ont., Canada. GALLAGHER, Paul (5 1935), 1209 Sixth St.. .Peru, and (for mail), 902 W. California, Urbana, 111 GALLIGAN, Andrew B. {M 1921), 716 South 51dt SL, Philadelphia, Pa. GALLOWAY, James F. (S 1934), 176 Clarkson Ave., Brooklyn, N. Y. GAMBLE, Gary B. (A 1935), Mgr., Sales and Engrg. (for mail), Crawford, Inc., 216 Baronne SL, and 732 St. Peter SL, New Orleans, La. GAMMILL, Oscar E., Jr. (7 1930), Sales Engr. (for mail). Carrier Engrg. Corp., 1416 Hibernia Bank Bldg., and 2133 Calhoun St., New Orleans, La. GANT. H. P.* {M 1915). {Presidential Member), (Pres., 1923; 1st Vice-Pres., 1922; 2nd VicePres., 1921; Council, 191S-1924), Vice-Pres. (for mail). Carrier Engrg. Corp., 12 South 12tb SL, and Penn Athletic Club, Philadelphia, Pa. GARDNER, S. Franklin (if 1911), Pres, (for mail). Standard Engrg. Co.. 2129 Eye St. N.W., and 4901 Hillbrook Lane, Washington, D. C. GARDNER. William (A 1921), Vice-Pres. (for mail). Garden City Fan Co., 1842 McCormick Bldg., and 7836 Loomis Blvd., Chicago. 111.-^' GARNEAU, Leo (7 1930), Sales Engr., Room 743 Dominion Square Bldg., and (for mail), 8454 Brouages St., Montreal. P. Q., Canada. GAULEY, Ernest R. (A 1935), Salesman. W. H. Cunningham & Hill, Ltd., 269-71 W. Richmond St., and (for mail), 110 Lee Ave., Toronto, Ont., Canada. GAULT, George W. (S 1934), (for mail), 1112 * Kelton Ave., Pittsburgh (16), and Marysville, Pa. GAUSMAN, Carl E. {M 1923). Mech. Engr., 1100 Minnesota Bldg., and (for mail), 2380 Chilcombe Ave., SL Paul, Minn. GAWTHROP, Fred H. {M 1919). Pres.. Gawthrop & Bro. Co., 705 Orange St., and (for mail), 2211 Shallcross Ave., Wilmington, Del. GAY, Lewis M. (A 1934), Power Engr. (for mail), Texas Power & Light Co., Box 962 Dallas, and 806 First Ave., Terrell, Texas. York, and (for mail), 31 French Ridge, New Rochelle, N. Y. GIBBONS. Michael J. (M 1914). Owner, M. J. Gibbons Supply Co.. 601-19 E. Monument Ave., and (for mail), 22 Oxford Ave., Dayton, Ohio. GIBBS, Edward W. (M 1919), Owner, The SmithGibbs Co.. 201 President Ave., and 39 President Ave.. and (for mail), 201 S. Main SL, Providence, R. I. GIBBS, Frank C. (M 1921), Gen. Supt. (for mail). National Regulator ` Co., 2301 Knox Ave., Chicago, and 150 N. Cuyler Ave., Oak Park, 111. GIESECKE, Frederick E.* (M 1913). (Council. 1932-1935), Director, Texas Engrg. Experiment Station, Agricultural and Mechanical College of Texas, College Station, Texas. GIFFORD, Clarence A. (A 1934), Salesman,. American Radiator Co., 374 Delaware Ave*, and (for mail), 247 North Drive, Buffalo, N. Y. GIFFORD, Robert L. (M 1908). Pres.. Illinois Engrg. Co., 21st SL and Radne Ave., Chicago, and (for mail), 1231 S. El Molino Ave., Pasadena, Calif. GIGUERE, George H. (Af 1920), Consulting Engr., 17205 Fairport Ave., Detroit, Micb. GILES, Alfred F. (7 1934), H. H. Robertson Co., 2000 Grant Bldg., and (for mail), 4307 Ludwick St., Pittsburgh, Pa. GILES, J. C. (5 1935), 546 S. Blvd., Norman, Okla. GILFRIN, George F. (M 1932), Eaplanada No. 715 Lomas de Chapultepec, and (for mail), Climas Artificiales S. A., Edif "La National,'' Mexico, D. F. GILL. John W. (5 1935). 2120 Carter Ave- St. Paul, Minn. GILLE, Hadar B. (M 1930), Consulting Engr., Hugo Theorells IngeniSrsbyra, Skoldungagatan 4, Stockholm, Sweden. GILLETT, M. C. (M 1916), Engr., 6600 Rising Sun Ave., Philadelphia, Pa. GILLHAM, Walter E. (M 1917), (Treasurer. 1926-1929; Council, 1926-1929), Consulting Engr. (for mail), 314 Inter-State Bldg., and 3427 Bellefontain Ave., Kansas City, Mo. GILLING, William F,, Jr. {Life Member 1934; M 1933'A 1919), AssL Mgr., American Radiator Co.. 12/ Federal SL, Boston, and (for mail), 29 Abbott Road, Wellesley Hills, Mass. 19 American Society of Heating o,nd Ventilating Engineers Guide, 1936 OILMAN, Franklin W. (Af 1935), Plant Engr.. (for mail), Atwater Kent Mfg. Co., 4700 Wissahickon Ave., and 514 W. Coulter St., Phila delphia, Pa. OILMORE, Louis A. (J 1935; 5 1930), Vice-Pres. (for mail). John Gilmore & Co., 13 N. Tenth St., and 6186 Westminster Place, St. Louis, Mo. CILMOUR, Alan B. (A 1932). Salesman, B. F. Gitmour Co., Inc., 152-41st St., and (for mail), GORNSTON, Michael H. (A 1923), Stationary Engr. (for mail), 430 Dumont Ave., Brooklyn, and 8504 Woodhaven Blvd., Woodhaven, N. Y. GOSSETT, Earl J. (Af 1923), Pres, (for mail). Bell & Gossett Co., 3000 Wallace St., Chicago, and 314 Woodland Ave., Winnetka, 111. GOTSCHALL, Harry C. (Af 1935). Instructor in Air Cond., Lane Technical High School, Western . Ave. and Addison St-, and (for mail), 4706 N. 543 East 18th St., Brooklyn,. N. Y. GINI, Aldo (M 1933), via Correggio 18, Milano, Italy. GINN, Tony M. (Af.1935), General Mgr., Sheet Metal, Roofing, Htg. and Vtg. (for mail), 10 , Fifth St. S., and 608 Sixth Ave. S., Great Falls, Mont. GIVIN, Albert W. (A 1925), Vice-Pres. (Stove Sales), (for mail). The Gurney Foundry Co., Ltd., Box 1149, and Apt. 4-S. 4870 Cote-des- Neiges Road, Montreal, P. Q.. Canada. GLANZ, Edward (A 1930), Pres, (for mail), Glanz & Killian Co., 1761 W. Forest Ave., and 3865 Lakewood Ave., Detroit, Mich. GLASS, William (Af 1934), Mgr. (for mail), Partridge-Halliday, Ltd., 144 Lombard St., Winnipeg, and 190 Braemar Ave., Norwood, Manitoba, Canada. GLASSEY, J. Wilbur (M 1922), Partner (for mail). Vapor Engrg. Co., 10 South ISth St., Philadelphia, and 7818 Ardleigh St., Chestnut Artesian Ave., Chicago, 111. GOTTWALD, C. (A 1916), Pres, (for mail), The Ric-Wil Co., Union Trust Bldg., Cleveland, and 2225 Stillman Road, Cleveland Heights, Ohio. GOUEDY, Kenneth E. (A 1935), Salesman and Engr. (for mail). Modern Building Insulating Co., 510 Bona Allen Bldg-, Atlanta, and 218 Columbia Drive, Decatur, Ga. GOULDING, William (A 1933), Engr., Air Cond., Electrical Research Products, National Broad casting Bldg., 711 Fifth Ave., New York, and (for mail), 360 East 19th St., Brooklyn, N. Y. GRABENSTEDER, Louis (J 1935), Power Sales Engr., Union Gas & Electric Co., and (for mail), 2853 Pine Grove'Ave., Cincinnati, Ohio. GRAHAM, Charles H. (Af 1934), Territorial Engr., The Lennox Furnace Co., Inc., 400 N. Midler Ave., Syracuse, and (for mail), 377 Highland Ave., Hamburg, N. Y. GRAHAM, Earl W. (J 1935), Student Engr. (for mail). Carrier Engrg. Coni., 180 N. Michigan Hill, Philadelphia, Pa. GLEASON. Gilbert H. (Af 1923), Partner (for mail), Gilbert Howe Gleason & Co., 25 Hunting Ave, Chicago, 111., and Bristow, Ky. GRAHAM, William D. (M 1929; A 1925; J 1923), Dist. Mgr. (for mail). Carrier Engrg. Corp., 890 ton Ave., Boston, and 10 Edgehill Road, Win chester, Mass. GLORB, Evins Foree (A 1916), Pres., Evins F. Glore Sales Corp., 1949 Grand Central Terminal, Union Trust Bldg., Cleveland, Ohio. GRAHN, Victor F. (Af 1927), Htg. and Vtg. Engr., Tenney & Ohmes, Inc., 101 Park Ave.. New York, N. Y.p and (for mail), 120 Greenwood and (for mad), 644 Riverside Drive, New York, N. Y. .. GOELZ, Arnold H. (Af 1931), Pres, (for mail). Kroeschell Engrg. Co., 2306 N. Knox Ave., Ave., East Orange, N. J. GRANSTON, Ray O. (J 1935; S 1930), Engr., Univ. Plbg. & Htg. Co., 3939 University Way, and (for mail), 4558 Fourth Ave. N.E., Seattle, Chicago, and 827 Greenwood Ave., Wilmette, III. GOENAGA, Roger C. (Af 1931). Tech. Director (for mail), Ateliera Ventil-109 Cours-Gambetta, Lyon, and 33 Avenue Valioud-Ste-Foy-les-lyon- Wash. GRANT, Walter A. (A 1933; J 1929), Develop ment Engr., Carrier Corp., 750 Frelinghuysen Ave., Newark, and (for mail), 1142 Anna St., Rhone, France. , GOERG, Bernard (M 1928), (for mail), American Radiator Co., 675 Bronx River Road. Yonkers, . and 294 Bronxville Road, Bronxville, N. Y. . GOLDBERG, Moses (A 1934), Pres., Electric . Motors Corp., 168 Centre St., New York, and (for mail), 1311 E. Seventh St,, Brooklyn, N. Y. GOLDSCHMIDT, Otto E. (Af 1915), Consulting Engr., 22 East 40th St., New York, N. Y., and (for mail), Westport, Conn. GOMBERS, Henry B. {Life Members A 1901), Secy, Emeritus, Heating, Piping & Air Condition . ing Contractors National Association, 1250 Elizabeth, N. J. GRAVES, Willard B. (Life Member; M 1906), Pres, (for mail), W. B. Graves Htg. Co., 162 N. Desplaines St., Chicago, 111. GRAY, Earle W. (A 1934), Commercial Dept., In charge of Air Cond., Sales (for mail); Okla homa Gas & Elec. Co., Box 1498, and 2125 Northwest 18th, Oklahoma City, Qkia. GRAY, George A. (Af 1924). C. A. Dunham Co., Ltd., 404 Plaza Bldg., Ottawa, Ont., Canada. GRAY, William E. (Af 1922). Sales Engr., Powers Regulator Co., 2720 Greenview Ave., Chicago, 111., and (for mail), Box 264, High Sixth Ave., New York, N. Y., and (for mail), 160 Halsted St., East Orange, N. J. GOODMAN, Daniel (5 1935), 2704 Filbury St., Pittsburgh, Pa. GOODRICH, Charles F. (Af 1919), Andrews & . Goodrich, Inc., Boston, and (for mail), 336 Adams St., Dorchester, Mass. GOODWIN, Samuel L. (Af 1924), Consulting Engr., 247 Madison Ave., Hasbrouck Heights, N. J. GOODWIN, Walter C. (Af 1933), Div. Engrg., Air Cond. Equip. Div. (for mail), Supply Engrg. Dept., Westinghouse Electric & Mfg. Co., East Pittsburgh, and 6032 Marie St., Pittsburgh, Pa. GORDON, Edward B., Jr. (Af 1908), Pres.. Pillsbury Engrg. Co., 1200 Second Ave., and (for mail), 2450 West 24th St., Minneapolis, Minn. GORDON, Peter B. (J 1935), Engr. (for mail), Point, N. C. : GREEN, Arthur W. (A 1935), 37-60-88th St., Jackson Heights, L. I., N. Y. GREEN, William C. (Life Member; Af 1906), Dist. Mgr. (for mail), Warren Webster & Co., 704 Race St., and 244 Erkenbrecher Ave (Arondale), Cincinnati, Ohio. . ' GREENBURG, Dr. Leonard* (Af 1932), Execu tive Dir. (for mail). Div. of Industrial Hygiene, N. Y. State Dept, of Labor, 80 Centre St., and 241 West 97th St., New York, N. Y. ` GREENLAND, Sidney F. (Af 1934), Engr., Gee Walker & Slater, Ltd., 32 St. James St., Read Berkeley Square, S.W. 1, and (for mail), 71 Arodene Road S.W. 2, London, England. GREER, Willis R. (J 1934), Air Cond. Engr., Arkansas Power & Light Co., and (for .mail), 1401 Linden St., Pine Bluff, Ark. GREINER, George E., Jr. (S 1935), 2149 Webster George E. Gibson Co., 441 Lexington Ave., New Ave., Pittsburgh, Pa. , ` York, N. Y:, and 35 Park Ave., Bloomfield, N. J. GRIFFIN, DeWitt C. (Af 1933), Secy-Treas. (for GORDON, William D. (A 1935), Air Cond. and Sales Engr., Tuttle & Bailey Mfg. Co. of Canada, Ltd., and (for mail), 29 Bowen Road, Ft. Erie N., mail). May & Griffin, Inc., 510 Orpheum Bldg., and 9717--47th S.W., Seattle, Wash. GRIMES, Fenner M. (J 1935). Engr., T. H. Ont., Canada. - GORDON, William J., Jr. (S 1935), 2208 Oliver Urdahl, Consulting Engr., 726 Jackson Place N.W., and (for mail), 7705 Alaska Ave. N.W., Ave. S., Minneapolis, Minn. . Washington, D. C. . 20 Roll of Membership CROSECLOSE, John B. (A 1929), Engr., Estimator, Dixie Heating & ventilating Co., 109 Fannin St., and (for mail), 3424 University Blvd., Houston, Texas. GROSS, Lyman C. (Af 1931), Sales Engr., Minneapolis-Honeywell Regulator Co., 2753 Fourth Ave. S., and (for mail), 4653-13th Ave. S., Minneapolis, Minn. .. CROSSMANN, Harry A. (M 1931) H. A. Gross- mann Co., 3221 Olive St., and (for mail), 3122 Geyer Ave., St. Louis, Mo. GROSSMAN, Harry E. (A 1933; J 1927), Sales Repr., Haynes Selling Co., Inc., 1518 Fair- mount Ave., Philadelphia, and (for mail), 218 Parkam Road, Springfield, Pa. GROVES, Samuel A. (J 1935), Salesman, Ameri can Radiator Co., 40 West 40th St-, New York, and (for mail), 70-10 Continental Ave., Forest Hills. L. I., N. Y. GUNTHER, Felix A * (Af 1925), Sales Engr. (for mail), 429-B Oliver Bldg., and Box 226 R. D. 9, S. Hills Branch, Pittsburgh, Pa. GURNEY, Edward Holt (Af 1929), (Council, 1931-1935), Pres, (for mail), Gurney Foundry Co., Ltd., 4 Junction Road, and 347 Walmer Road, Toronto, Ont., Canada, H HAAS, Emil, Jr. (J 1929), Secy-Treas. (for mail). Natkin & Co., 2020 Wyandotte, and Newbem Hotel, Kansas City, Mo. HAAS, Richard B. (S 1935), Box 561 East Lansing, Mich. HAAS, Samuel L. (Af 1923), Pres, (for mail). Advance Heating Co., 117-19 N. Desplaines St-, and 1513 Fargo Ave., Chicago, 111. HAATVEDT, Sheldon R. (S 1935), 408 Fourth St. S. E., Little Falls, Minn. HACKETT, H. Berkeley (Af 1921). 901 Archi tects Bldg., 17th and Sansom Sts., Philadelphia, 'Pa. HADDOCK, Isaac T. (A 1926), New England Gas & Elec. Assn., 719 Massachusetts Ave., Cambridge, Mass. ' HADEN, G. Nelson (Af 1934; A 1928; J 1922), Managing Director (for mail), G. N. Haden & Sons, Ltd., 60 Kingsway, London W. C. 2, and 36 Wildwood Road, Hampstead Heath, London N.W. 11. England. . HADEN, William Nelson (Life Member; M1902), Late Chairman, G. N. Haden & Sons, Ltd., St- Georges Works, and (for mail), Arnolds Hill, Trowbridge, Wilt., England. HADESTY, Alfred L., Jr. (Af 1921), 130 E. Broad St., Tamaqua, Pa. HADJISK.Y, Joseph N. (Af 1930), Consulting Engr., 744 Bates St., Birmingham, Mich. HAGAN, William V. (A 1933; J 1926), Secy.,. V. J. Hagan Plbg. &.Htg. Co., 506 Pearl St., and (for mail), 1811 Jones St., Sioux City, Iowa. HAGEDON, Charles H. (Af 1919), S. E. Fenster- maker 8c Co., 939 Architects-Builders Bldg., Indianapolis, Ind. . HAINES, John J. (Af 1915), Pres, (for mail). The Haines Co., 1933 W. Lake St., Chicago, and 623 17th Ave., Maywood, 111. HAJEK, William J. (Af 1932). Resident Vice- Pres. (for mail), Minneapolis-Honeywell Regu lator Co-, 285 Columbus Ave., and 56 Common wealth Ave., Boston, Mass. HAKES, Leon M. (Af 1932; A 1932; J 1929), Sales Engr. (for mail). The R. T. Coe Co., 400 Rey nolds Arcade Bldg., and 71 Strathmore Drive, Greece, Rochester, N. Y. HALE, John F. (Af 1902), (Presidential Member), (Pres., 1913; 1st Vice-Pres., 1912; Board or Governors, 1908-1910, 1912-1913), Dist Mgr. (for mail), Aerofin Corp., Ill W. Washington St., R 1058, Chicago, and 416 S. Brainard Ave., .LaGrange, 111. . HALEY, Harry S.* (Af 1914), Consulting Engr., . Partner (for mail), Leland 8c Haley,. 58 Sutter St., and 735-21st Ave., San Francisco. Calif. HALL, John R. (J 1932), Mech. Engr., U. S. Air Cond. Corp., 2101 N.E. Kennedy St., and (for mail), 1416 Lakeview Ave., Minneapolis, Minn. HALL, Mora S. (Af 1934), Dev. Engr. (for mail). May Oil Burner Corp., Maryland and Oliver St., Baltimore, and R. Route No. 3, Westminster, Md. HAMENT, Louis (A 1933), Mgr. (for mail). Aquatic Chemical 8c Metallurgical Engrs., 118 East 28th St., and 568 East 166th St., New York. N. Y. HAMERSKI, Francis D. (J 1934), Combustion and Htg. Engr., 3933 Bryant Ave. S-, Minne- ' apolis, Minn. HAMIG, Louis L. (J 1935), Sales Engr., Weber Airtemp Corp., 1815 Locust St., and (for mail), 3514 Utah St., St. Louis, Mo. HAMILTON, James E. (A 1933), Mgr. (for mail), U. S. Radiator Corp., 4004 Duncan Ave., St. Louis, and 7715 Shirley Drive, Clayton, Mo. HAMLIN, Chauncey J., Jr. (A 1934), Hamlin Air Conditioning Co., and (for mail), 1014 Delaware Ave., Buffalo, N. Y. . HAMLIN, Harry A. (A 1916), Sales Engr. (for mail), Johnson Service Co., 427 Brainard St., Detroit, and 120 Winona, Highland Park, Mich. HANCE, W. Wayne (A 1935), Draftsman, E. I. DuPont de Nemours Co., Wilmington, Deli, and (for mail), 32 Owen Ave., Lansdowne, Pa. HANKINS, Richard P. (J 1935), Engr. and Draftsman (for mail), G- A. Peple, Jr., Consulting Engr., 925 American Bldg., and 1826 Hanover Ave., Richmond, Va. HANLEY, Edward V. (A 1933), Pres, (for mail); S. V. Hanley Co.. 1653 N. Farwell Ave., Mil waukee, and 844 E. Birch Ave., Whitefish Bay, Wis. HANLEY, Thomas F., Jr. (Af 1933), Pres, (for mail), Hanley & Co., 1503 S. Michigan Ave., and 4940 East End Ave., Chicago, 111. HANSEN, Charles C. (Af 1928). Engr., 428 Prospect St., South Orange, N. J. HANSON, Leslie P. (/ 1935; S 1933), Engr., U. S. Air Cond. Corp., 2101 N.E. Kennedy, and (for mail), 4336--46th Ave. S., Minneapolis, Minn. HARDING, Louis A * (Af 1911), (Presidential Member), (Pres., 1930; 1st Vice-Pres., 1929; 2nd Vice-Pres., 1928; Council, 1922-1931), Pres, (for mail), L. A. Harding Construction Corp., Prudential Bldg., and 85 Cleveland Ave.,- Buffalo, N. Y. RARE, W. Almon (Af 1930), 40 Reedraere Road, Riverside, Ont., Canada. HARMONAY, William L. (A 1935), Mgr. (for mail), M. J. Harmonay, Inc-, 124 Elm St.,, and 34 Alida St., Yonkers, N. Y. HARMS, William T.* (Af 1917), 1015 Vinewood Ave., Detroit. Mich. HARRIGAN, Edward M. (M 1915), (for mail), Harrigan & Reid Co., 1365 Bagley Ave.; and 7450 LaSalle Blvd-, Detroit, Mich, HARRINGTON, Charles (Af 1923), 43 Indian Grove, Toronto, Ont., Canada. HARRINGTON, Elliott* (Af 1932; A 1930), Mgr., Commercial Engrg. Div., Air Cond. Dept, (for mail). General Electric Co., 5 Lawrence St., Bloomfield, and 5 Wilson Terrace, West Cald- . well, N. J. HARRIS, Jesse B. (Af 1918), Pres, (for mail). Rose & Harris Engrs., Inc., 416 Essex Bldg., and 3620 Colfax Ave. S., Minneapolis, Minn. HART-BAKER, Henry W. (Af 1918), Director (for mail), Merritt, Ltd., 8 French Bund, and 37 Rte Rene, Delastre, Shanghai, China. HART, Harry M-* (M . 1912), (Presidential Member), (Pres., 1916; 1st Vice-Pres., 1915; Council, 1914-1917), Pres, (for mail), L. H. Prentice Co., 1048 Van Buren St., and 3730 Sheridan Road, Chicago, 111. HARTIN, William R., Jr. (/ 1935), Htg. Engr., . W. R. Hartin & Son, 830 Harden St., and (for mail), 212 S. Saluda Ave., Columbia, S. C. 21 of andAmerican Society Heating Ventilating Engineers Guide, 1936 HARTMAN, Fred Stewart (A 1933). Dist. Mgr., Industrial Dept, (for mail). General Electric Co.', 570 Lexington Ave.. New York, N. Y., and 168 Montclair Ave., Montclair, N. J. HARTMAN, John M. (M 1927). Engr. (for mail), Kewanee Boiler Corp., and 719 Henry St., Kewanee, 111. HARTON, A. J. (A 1935). Sales Engr., St. Joseph Railway Light Heat & Power Co., Sixth and ' Francis, and (for mail), 701. E. Hyde Park, St. Joseph, Mo. HARTWE1N, Charles E. (M 1933), Supervisor, House Htg. Dept., St. Louis County Gas Co., 231 W. Lockwood, Webster Groves, and (for mail), 6271 Magnolia Ave., St. Louis, Mo. HARTWELL, Joseph C. (M 1922), (for mail), Hartwell Co.. Inc., 87 weybosset St., and 16 Freeman Pkwy., Providence, R. I. HARVEY, Alexander D. (A 1928; J 1925), Nash Engrg. Co., South Norwalk. Conn. HARVEY, Lyle C. (M 1928), Vice-Pres. (for mail), Bryant Heater Co., 17825 St. Clair Ave., and 3388 Glencarin Road. Cleveland, Ohio. HASHAGEN, John B. (M 1930), 121 Manhattan Ave., Jersey City, N. J. HASLETT, Henry M. (S 1935), 950 Lombard Ave., St. Paul, Minn. HATEAU, William M. (,7 1934), Draftsman and Designer, Sherron Metallic Corp., 1201 Flushing Ave., Brooklyn, and (for mail), 1530 Sheridan Ave./ New York, N. Y. HATTIS, Robert E. (M 1926), Consulting Engr. (for mail), 820 N. Michigan Ave., and 4251 N. Mozart St., Chicago. 111. HAUAN, Merlin J, (M 1933), Consulting Engr., 3412-16th S., SeatUe, Wash. HAUPT, Howard F. (A 1929), Htg. Salesman. Kohler Co., 751 N. Jefferson Si., and (for mail), 614 E. Beaumont Ave., Milwaukee, Wis. HAUS, Irvin J. (7 1935), Commercial Engr., Morley-Murphy Co., 342 N. Water St., Mil waukee, and (for mail), 925 Division St., Green Bay, Wis. HAUSMAN, Louis M. (M 1935), Pres., L. M. Hausman & Co.. Inc., 440 Dasmari&as, and (for mail), P. O. Box 1729, Manila, P. I. HAUSS, Charles F.* (Charter Member; Life Member), Via Gioberti No. 2, Milano, Italy. HAYDEN, Carl F. (A 1930). Branch Mgr. (for mail), Barber-Colman Co., 221 N. LaSalle St., Chicago, and 2227 Ewing Ave., Evanston, 111. HAYES, James J. (M 1920), Sales Engr. (for mail). Standard Power Equipment Co., Room 925, 53 W. Jackson Blvd., and 7443 Jeffery Ave., Chicago, 111. HAYES, John J. (A 1933), Auburn Stoker Sales Corp., 406 N. Wells St., Chicago, 111., and (for mail), 918 Michigan Ave., Evanston, 111. HAYES, Joseph G. (M 1908), Pres, and Engr. (for mail), Hayes Bros., Inc., 236 W. Vermont St., and 2849 N. Capitol Ave., Indianapolis, Ind. HAYMAN, A. Eu&ene, Jr. (7 1935; S 1930), Engr., 2500 Washington St., Wilmington, Del. HAYNES, Charles V. (M 1917), (Presidential Member), (Pres., 1934; 1st Vice-Pres., 1933; 2nd Vice-Pres., 1932; Council. 1926-1929: 1932 1935), Vice-Pres., Hoffman Specialty Co., 500 Fifth Ave., Room 3324, New York, N. Y., and (for mail), 115 Llanfair Road, Ardmore, Mont., Co., Pa. HAYTER, Bruce (M 1934), Chief Engr., Institute of Thermal Research (for mail), American Radia tor Co., 675 Bronx River Road, Yonkers, and 49 Carman Road, Scarsdale, N. Y. HAYWARD, Ralph B. (M 1909), Pres, (for mail), R. B. Hayward Co., 1714 Sheffield Ave., Chicago, and 201 S. Stone Ave., LaGrange, III. HEARD* John A. E. (7 1930), Asst. Mgr. (for mail), Carrier Engrg. Co., Ltd., Connaught Place, New Delhi, India, and 28, Leighcliff Road, Leigh on Sea, Essex, England. HEARD, Roderick G. (A 1933), Oil Burner Sales Dept, (for mail). Imperial Oil, Ltd., 56 Church St., and 158 Highbourne Road, Toronto, Ont., Canada. HEATH, William R. (M 1931), Asst. Chief. Engr.. Buffalo Forge Co., 490 Broadway, and (for mail), 119 Wingate Ave., Buffalo, N. Y. HEBERLING, C. W. (A 1934), Box 115, Wayzata, Minn. HEBLEY, Henry F. J. (M 1934), Research Engr.. Allen & Garcia Co., Consulting Engrs., Room 2047-332 S. Michigan Ave., and (for mail), 636 Wrightwood Ave., Chicago, 111. HECHT, Frank H. (M 1930), Sales Engr. (for mail), B. F. Sturtevant Co., 2635 Koppers Bldg., and 1467 Barnesdale St., Pittsburgh, Pa. HECKEL, E. P. (M 1918). Vice-Pres., Sales Mgr., Carrier Engrg. Corp., 180 N. Michigan Ave., Chicago, and (for mail), 314 Cuttriss Place, Park Ridge, 111. HEDGES. H. Berkley (M 1919), Mgr. of Indus trial Sales, J. J. Nesbitt, Inc., Holmesburg, Philadelphia, Pa., and (for mail), 1021 Park Lane, Plainfield, N. J. HEDLEY, Park S. (M 1923), Park S. Hedley Co., Curtiss Bldg., Delaware at Tupper, Buffalo, N. Y. HEEBNER. Walter M. (M 1922), Sales Engr.. Warren Webster & Co., 470 Fourth Ave., New York, N. Y., and (for mail), 282 Highwood Ave., Teaneck, N. J. HEIBEL, Walter E. (M 1917), Dist. Mgr. (for mail), Aerofin Corp., 11 West 42nd St., New York, N. Y., and Old Greenwich, Conn. HEILMAN, Russell H.* (M 1923), Senior Industrial Fellow (for mail), Mellon Institute, and 5637 Wilkins Ave., Pittsburgh, Pa. HELBURN. I. B. (M 1929; 7 1927), Junior Assoc, (for mail), Wyman Engrg., Chamber of Com merce Bldg., and Apt. 17., 700 Chalfonte Place, Cincinnati, Ohio. HELLSTROM, John (A 1929). Vice-Pres. (for mail), American Air Filter Co., 215 Central Ave., Louisville, and Anchorage, Ky. HENDRICKSON, Harold M. (M 1933), Engr. (for mail), York Ice Machinery Corp., 6051 Santa Fe Ave., Los Angeles, and 7022 Middleton St., Huntington Park, Calif. HENION, Hudson D. (A 1923). Sales Mgr. (for mail), C. A. Dunham Co., Ltd., 1523 Davenport Road, and 45 Ridge Drive, Toronto, Ont., Canada. HENRY, Alexander S., Jr. (M 1930), 300 Central Park W., New York, N. Y. HENSZEY, William P. (7 1935), Engr., Carrier Engrg. Corp., 12 South 12th St., Philadelphia, and (for mail), Sabine Apts., Narberth, Pa. HERENDEEN. Frederick W. (M 1920), Secy, (for mail). The Institute of Boiler & Radiator Mfrs., 29 Seneca St., and 815 S. Main St., Geneva, N. Y. HERING, Alfred (M 1935), Pres.. Hering Htg. Co., Inc., 1657 Lexington Ave., and (for mail), 1830 Tenbroeck Ave., New York, N. Y. HERKIMER, Herbert (M 1934), Director (for mail), Herkimer Institute, 1819 Broadway, and 25 Central Park W., New York. N. Y. HERLIHY, Jeremiah J. (Life Members M 1914), Pres, (for mail), J. J. Herlihy, Inc., 810 W. Con gress St., and 3634 N. Keeler Ave., Chicago, 111. HERRICK, Leo (M 1935). Mgr. (for mail). Crane Co., 521 S. Ninth, and 323 Greenwood Ave., Fort Smith, Ark. HERRING, Edgar (M 1919), Chairman and Governing Director (for mail), J. Jeffreys & Co., Ltd., Barrons Place. Waterloo Road, London S. E., and " Kenia,'1 Keswick Road, Putney, London S. W., England. HERSKE, Arthur R. (M 1926). Vice-Pres., Gen. Mgr. Sales (for mail), American Radiator Co., 40 West 40th St., New York, and 25 Vernon Pkwy., Mt. Vernon, N. Y. HERTY, Frank B. (M 1933), House Htg. Super visor, Brooklyn Union Gas Co., 180 Remsen St.,, and (for mail), 50 East 18th St., Brooklyn, N. Y. HERTZLER, John R. (7 1928), Air Cond. Sales Engr.. York Ice Machinery Corp., York, Pa. HESS, David K. (S 1932), Hess Wanning & Vtg. Co., 1211-1227 S. Western Ave., Chicago, 111., and (for mail), 627 Mendota Court, Madison, Wis. 22 Roll of Membership HESTER, Thomas J. (M 1919), Vice-Pres-Treaa. (for mail), Hester-Bradley Co., 2835 Washington Blvd., and 67 Aberdeen Place, St. Louis. Mo. HEWETT, John B. (A 1935), Engrg. Mgr., Hudson Air Cond. Corp., 1517 Connecticut Ave., and (for mail), 1627 Kennedy Place, N.W., Washington, D. C. HEXAMER, Harry D. (M 1931), Sales Engr. (for mail), Excelso Products Corp., 65 Clyde Ave., and 163 E. Delavan Ave., `Buffalo, N. Y. HEYDON, Charles G. (A 1923), Mgr. Sales of Western Div., Wright-Austin Co., 315 W. Wood - bridge St., and (for mail), 2681 Nebraska, Detroit, Mich. HIBBS, Frank C. (M 1917), Salesman, The H. B. Smith Co., 2209 Chestnut St., and (for mail). 846 North 65tb St., Philadelphia, Pa. HICKEY, Daniel W. (A 1931), 278 W. Fourth St., St. Paul, Minn. HICKS, H. Kimble (5 1935), American Radiator Co., 40 West 40th St., and (for mail), 215 East 15th St., New York, N. Y. H1ERS, Charles R. (M 1929; A 1929; 7 1927), Sales Engr., Minneapoli9-Hooeywell Regulator Co., 801 Second Ave., New York, and (for mail), 45-18-258th St., Great Neck, L. I., N. Y. HIGGINS, Thomas J. (M 1927; A 1927; 7 1923), P. O. Box 17, E. Dedham, Mass. HILDEBRANDT, Henry A. (M 1918), Elliott Equipment Co., 708 Sixth Ave. S. Minneapolis, Minn. HILDRETH, Lane W. (M 1935), Dist. Mgr. (for mail), Anthracite Institute, 19 Rector St., New York, N. Y., and 221 Wheatsheaf Lane, Abington, Pa. HILL, Dr. E. Vemon*.(M 1914; A 1912), (Presi dential Member), (Pres., 1920; 1st Vice-Pres., 1919; 2nd Vice-Pres.. 1918; Council, 1915-1921), Pres, (for mail), E. Vernon Hill Co., 121 N. Clark St., and 1126 Farwell Ave., Chicago, 111. HILL, Fred M. (M 1930), 225 East Ave.-39.t Los Angeles, Calif. HILL, Harold H. (M 1935), Field Engr., Frigidaire Corp., and (for mail), 508 Forest Ave., Dayton, Ohio. . HILLIARD. Charles E. (M 1932; J 1927), Htg. and Vtg. Engr. (for mail), E. C. Hilliard Co., 27 B St., South Boston, and 1301 Washington St., South Braintree, Mass. HILLS, Arthur H. (M 1924), Mgr., Sarco Canada, . Ltd., 725-6 Federal Bldg., 85 Richmond St. W., Toronto, Ont., Canada. HINCKLEY, Harlan B. (A 1934), Engr. Custo dian., Board of Education, 8510 S. Green St., and (for mail), 6933 Princeton Ave., Chicago, 111. HINKLE, Edwin C. (Life Member; M 1911), 170 N. Franklin St.. Hempstead, N. Y. HINRICHSEN, Arthur F. (M 1928). Pres-Treas. (for mail), A. F. Hinrichsen, Inc., 50 Church SL, ` New York, N. Y., and Mountain Lakes, N. J. HINTZ, Harvey P. (S 1935), 211 E. Armory Ave., Champaign. 111. , HIRES,. J. Edgar (M 1927). Pres, (for mail). Hires Castner & Harris, Inc., 206 South 24th, Philadelphia, and 107 Linwood Ave., Ardmore, Pa. ` HIRSCHMAN, William F. (M 1929). Pres, and Chief Engr., W. F. Hirschman Co., Inc., 220 Delaware Ave., and (for mail), 165 Le Brun Circle, Buffalo, N. Y. HITCHCOCK, Paul C. (M 1931), Partner (for mail), Burlingame & Hitchcock, 626 Sexton Bldg., and 4939 Girard Ave. S., Minneapolis, Minn. HOBBS, J- Clarence (M 1920), 60 Wood St., Painesville, Ohio. HOCHSTEIN, George E. (A 1935), Sales Engr. (for mail), Hell Co., 3000 W. Montana, and 2632 N. Oakland Ave., Milwaukee, Wis. . HOCHUL1, Henry W. (M 1925). Sales Engr., National Radiator Corp., 55 West 42nd St., New / York, N. Y., and (for mail), 113 Chester Ave., Bloomfield, N. J. . HODEAUX, W. L. (M 1931), Owner (for mail), W. L. Hodeaux Plbg. & Htg. Co., 215-17 N. Flager Drive, and 310 Tenth St., West Palm Beach, Fla. HODGDON, Harry A. (M 1919). 153 Norfolk St.. Wollaston, Mass. HODGE, William B. (M 1934), Vice-Pres., Parks Cramer Co., and (for mail), P. O. Box 1234, Charlotte, N. C. HOEHL, Edward R. (7 1935), Air Cond- Engr. (for mail). Carrier Engrg. Corp., 408 Chrysler Bldg., New York, and 645 Jefferson St, West New York, N. J. HOFFMAN, Charles S. (M 1924), Vice-Pres. (for mail). Baker Smith'& Co., Inc., 576 Greenwich St., and 75 Central Park W., New York, N. Y. HOFFMAN, James D * (M 1903), (Presidential Member), (Pres., 1910; 1st Vice-Pres., 1908; Board of Governors, 1911-1912), Prof, of Practi cal Mechanics, Head of Dept., Director of Practical Mech. Lab. (for mail), Purdue Uni versity. and 323 University St., West Lafayette, Ind. HOFT, Paul J. (M 1925; A 1924), (for mail), 245 S. Eighth St., and 1119 Wyoming Ave., Phila delphia, Pa. HOGAN, Edward L.* (M 1911), Consulting Engr. (for mail), American Blower Co., 6000 Russell St., and 700 Seward Ave., Detroit, Micb. HOGUE, William M. (A 1935), Sales Engr. (for mail). U. S- Electrical Mfg. Co., 200 E. Slauson Ave.. and 602 N. Manhattan Place, Los Angeles, Calif. HOLBROOK, Frank M.* (M 1923), Engr., Apt. J-l-5, 10 Lexington St., Newark, N. J. HOLLISTER, E. Wallace (7 1931). Owner, Hollister's, 21 Bay St., Glen Falls, and (for mail), 88 Oak St., Hudson Falls, N. Y. HOLLISTER, Norman A. (M 1933), (for mail), 7101 Colonial Road, Brooklyn, N. Y. HOLMES, Arthur D. (M 1935), Sales Engr. (for mail). Plumbers Supply Co., 323 W. First, and 711 S. Cheyenne, Tulsa, Okla. HOLMES, Richard E. (7 1934), Engr., Air Cond., Westinghouse Elec. & Mfg. Co., Page Blvd., and (for mail), 11 Bushwick St., Springfield, Mass. HOLT, James (M 1933), Assoc. Prof, (for mail), Massachusetts. Institute of Technology, Cam- bridge, and 1062 Massachusetts Ave., Lexington, Mass. HOLTON. John H. (M 1927). Asst. Chief Engr. (for mail). Carrier Engrg. Corp., 850 Freling- buysen Ave., Newark, and 5 Mountain Ave., . Maplewood, N. J. HOOD, O. P. (Honorary Member 1929), Chief, Technologic Branch (for mail), U. S. Bureau of Mines. 901- Washington Loan & Trust Bldg., Ninth and F Sts., and 1831 Irving St. N.W., Washington, D. C. HOOPER, Vernon F. (M 1929), 61 Eastern Ave., Ossining, N. Y. HOPP, Herbert K. (5 1935), 530 McLean Ave., Yonkers, N. Y. HOPPE, Albert A. (M 1935), Design and Applica tion Engr.. Carrier Engrg. Corp., and (for mail), 524 Northwest 17th, Oklahoma City, Okla. HOPPER, Garnet H. (M 1923), Engr., Taylor Forbes, Ltd., 1088 King St. W., and (for mail), 19 Brummell Ave., Toronto, Ont., Canada. HOPSON, William T. (Life Member; M 1915), The Hopson & Chapin Mfg. Co., New London, Conn. HORNUNG, John G. (M 1914), Engr. (for mail). Central Heat Appliances, 343 S. Dearborn St., Chicago, and 854 Bluff St., Glencoe, 111. HORTON, Homer F. (M 1925), Sales Repr. (for mail). National Regulator Co., 2301 Knox Ave., Chicago, and 1301 Judson Ave., Evanston, 111. HOSHALL, Robert H. (M 1930). Associate (for mail), Thos. H. Allen, Consulting Engr., 65 McCall St., and 789 N. Evergreen St., Memphis, Tenn. . HOSKING, Homer L. (M 1930), Branch Sales Mgr. (for mail). Pacific Steel Boiler Corp., 370 Lexington Ave., New York, and 5 Church Lane, Scarsdale, N. Y. ` 23 American Society of Heating and Ventilating Engineers Guide, 1936 HOSTERMAN, Charles O. (M 1924). Supt., The McMurrer Co., 303 Congress St., Boston, and (for mail), 25 Bateswell Road, Dorchester, Mass. HOTCHKISS, Charles H. B. (Af 1927). Editor, Heating and Ventilating, 148 Lafayette St., New York, N. Y. HOUGHTEN, Ferry C.* (Af 1921), Director (for mail). Research Lab., A.S.H.V.E., U. S. Bureau of Mines, 4800 Forbes St., and 1136 Murray Hill Ave., Pittsburgh, Pa. HOULIS, Louis D. (Af 1935), Chief Engr., Master Baker Ovens, Batavia, and (for mail), 655 Pedretti Road, West Price Hill, Cincinnati, Ohio. HOULISTON, G. Baillie (A 1928), Secy, (for mail). W. C. Green Co., 704 Race St., Cincinnati, Ohio, and 33 Tremont Ave., Ft. Thomas, Ky. HOWARD, Edgar S. (S 1935), 2721 Blaisdell Ave., Minneapolis, Minn. ' HOWATT, John* (Af 1915), {Presidential Member) (Pres., 1935; 1 st Vice-Pres., 1934; 2nd.Vice- Pres., 1933; Council, 1927-1936), Chief Engr. (for mail), Board of Education. 228 N. LaSalle St., and 4940 East End Ave., Chicago, 111. HOWELL, Frank B. (Af 1920), Tech. Advisor (for mail), American Radiator Co., 40 West 40th St., and 15 Central Park W., New York, N. Y. HOWELL, Lloyd {M 1915), Htg. Vtg. and Air Cond. Engr., 325 Peoples Gas Bldg., and (for mail), 7601 Yates Ave., Chicago, 111. HOWLETT, Ira G. (Af 1935; S 1934). Consulting Engr. (for mail), Howlett-Tauson Co., 120 E. Main St., and 2132 N. Fonshill Ave., Oklahoma City, Okla. HOYT, Charles W. (A 1931), Pres-Treas. (for mail). Wolverine Htg. and Vtg. Equip. Co., 80 Boylston St., Boston, and 45 Thaxter Road, Newtonville, Mass. HOYT, Leroy W. (Af 1930), N. Stamford Ave., Stamford, Conn. HUBBARD, George Wallace* (Af 1911), Chief Mech. Engr. (for mail), Graham Anderson Probst & White, 1417 Railway Exchange, Chicago, and 710 Bonnie Brae, River Forest, 111. HUCH, A. J. (Af 1919), Secy-Treas. (for mail). Central Supply Co., 312 S. Third St., and 4037 Harriet Ave., Minneapolis, Minn. HUCKER, Joseph H. (Af 1921), Partner, Hucker- Pryibil Co., 1700 Walnut St., Philadelphia, and (for mail), 715 Stanbridge St., Norristown, Pa. HUDSON, Robert A. (Af 1934), Consulting Engr. (for mail). Hunter & Hudson, Room 710,- 41 Sutter St., and 285(1 Union SL, San Francisco, Calif. HUETTNER, Henry F. (5 1934), 124 Jerusalem Ave., Hickesville, L. I., N. Y., and (for mail). Box 388, Carnegie Tech., Pittsburgh, Pa. HUFFAKER, Herbert B. (Af 1933), Engr., Bennett Co., 1111 Harney St., Omaha, Nebr., and (for mail), 414 N. Eighth St., Council Bluffs, Iowa. HUGHES, Charles E. (S 1934), 140 Beacon Ave.. New Haven, Conn. HUGHES, Frank, Jr. (A 1935), Sales and Esti- . nator (for mail), Hardin Sash & Door Co., 400 S. Lake St., and 2905 Travis Ave., Ft. Worth, Texas. HUGHEY, Thomas M. (A 1935), Sales Engr. (for mail), Westerlin & Campbell Co., 906 N. Fourth . St., and 2350 North 58th St. Milwaukee, Wis. HUGONIOT, Victor E. (Af 1935), Engr., Weber Airtemp Corp., 1815 Locust St., and (for mail), 6289-A Bartmer Ave., St. Louis, Mo. HULL, Harry B. (Af 1931), Mgr., Research Engr., Frigidaire Corp., and (for mail), P. O. Box 671, Dayton. Ohio. HUMPHREY, Dwight E* (Af 1921), Htg. and Vtg. Engr., Goodyear Tire & Rubber Co., 1144 E. Market St., Akron, and (for mail),. 2499 Sixth St.. Cuyahoga Falls, Ohio. . HUMPHREYS, Clark M. (Af 1931), Asst. Prof, (for mail). Carnegie Institute of Technology. Schenley Park, and 1934 Remington Drive, Pittsburgh, Pa. HUNGER, Robert F. (Af 1927), Associate Dist. Mgr. (for mail), Buffalo Forge Co., 703 Cunard Bldg., and 4618 Chester Ave., Philadelphia, Pa. HUNGERFORD, Leo (Af 1930), Pres, (for mail). Pacific Elec. & Mech. Co., Inc., 524 Loews State Bldg., and 105 N. Berendo St.. Los Angeles, Calif. HUNT, Noel P. (Af 1934), Managing Dir., (for mail). Carrier Australasia, Ltd., 41-49 Forbes St., and 52 Lang Road, Centennial Park, Sydney N.S.W., Australia. HUNZIKER, Chester E. (A 1934). Branch Mgr. (for mail), American Blower Corp., 331 State St., Schenectady, and 422 Reynolds St., Scotia, N. Y. HUSKY, S. T. (S 1934), 710 Monnett St., Norman, HUST,' Carl E. (Af 1932), Htg. Engr. (for mail). The Union Gas & Elec. Co., Room 1008, Fourth . and Main Sts., and Hillcrest Apts., 15 Mason St., Cincinnati, Ohio. HUSTOEL, Arnold M. (A 1930), 2623 N. Ballou St., Chicago, 111. HUTCHINS, William H. (Af 1934), Chief Engr., Delco Appliance Div., General Motors Corp., and (for mail), 88 Magee St., Rochester, N. Y. HUTZEL, Hugo F. (Af 1918), 2635 Woodstock Drive, Detroit, Mich. HVOSLEF, Fredrik W. (Af 1931; A 1921), Htg. Research Engr. (for mail), Kohler Co., and 523 Audubon Road, Kohler. Wis. HYDE, Lawrence L. (7-1934), Gen. Mgr., M. J. O'Neil, and (for mail), 54 S. Cretin St., St. Paul, Minn. ' HYMAN, Wallace M. (Af 1920), Pres, (for mail). Reis & O'Donovan, Inc., 12 West 21st St,, and 23 West 73rd St., New York, N. Y. HYNES, Lee P.* (Af 1919). Pres, (for mail), Hynes Electric Htg. Co., 240 Cherry St., Phila delphia, Pa., and 127 West End Ave., Haddon- field, N. J. ICKER1NGILL, J. C. (Af 1923), Engr., Spencer Heater Co., 2504 N. Broad St., and (for mail),. 235 Rector St., Philadelphia, Pa. ILLIG, Walter R. (Af 1935; A 1927), Owner, 1 Cushing St., and (for mail). 149 South St., Fitchburg, Mass. _ INGALLS, Frederick D. B. (Af 1906), Consulting Htg. Engr., 1 Hopkins St., Reading, Mass. INGELS. Margaret* (Af 1923; 7 1918), Mech. Engr. (for mail). Carrier Engrg. Corp., 850 Frelinghuysen Ave., Newark, and Hotel East Orange, East Orange, N. J. '^ ISSERTELL, Henry G.* (Af 1913; A 1912), Consulting Engr., 31 Park Terrace W., New York, N. Y. JACKSON, Alton B. (Af 1932), 15 Herrick St., Winchester, Mass. _ * JACKSON, Charles H. (Af 1923), Vice-Pres. (for mail)', Blower Application Co., 918 N. Fourth St., and 2706 N. Farwell Ave., Milwaukee, Wis. JACKSON, Marshall S. (Af 1919), Repr. (for mail). Powers Regulator Co., 250 Delaware Ave., and 108 Larchmont Road, Buffalo, N. Y. JACOBUS, Dr. David S. (Life Member; Af 1916), Advisory Engr. (for mail). The Babcock & Wilcox Co., 85 Liberty St., New York, N. Y,, and 93 Harrison Ave., Montclair, N. J. JALONACK, Irwin G. (A 1933; S 1930), Engrg. Mgr. (for mail), c/o A. L. Hart, 82 Railroad Ave., and 15 South St., Patchogue, N. Y. JAMES, Hamilton R. (Af 1931), Service Equip. . Engr., United Engineers & Constructors, Inc., 1401 Arch SL, Philadelphia, and (for mail), 55 W. Drexel Ave., Lansdowne, Pa. JAMES, John W.* (71933), Tech. Asst, (for mail), American Society of Heating and Ventilating Engineers, 51 Madison Ave., New York, N. Y. JANET, Harry L. (M 1920), Engr. (for mail). Carrier Engrg. Corp., Chrysler Bldg., New York, and 688 Decatur St., Brooklyn. N. Y. 24 t Roll of Membership JARDINE, Douglas C. (Af 1929; A 1926), Pres, (for mail), Jardine & Knight Plbg. & Htg. Co.,' 312 N. Custer Ave.; and 1512 E. Platte Ave., Colorado Springs, Colo. JARRATT, Paul R. (A 1931), 117 Fifth Ave. N., Nashville, Tenn. JEFFREY, Thomas G. (A 1935), Mgr. (for mail), Bastian-Morley, Ltd., 2362 Dundas St. W., and 478 Windemere Ave., Toronto, Ont., Canada. JENNEY, Hugh B. (A 1933), Gen. Sales Mgr. (for mail). Dominion Radiator & Boiler Co.. Ltd., Royce and Lansdowne Aves., and 45 Quebec Ave., Toronto, Ont., Canada. JENNINGS, Irving C. (Af 1924), Pres, (for mail), Nash Engrg. Co., and 138 Flax Hill Road, South Norwalk, Conn. JENNINGS, Stanley A. (Af 1935), Chief Drafts man, Trane Co. of Canada, Ltd., 439 King,St. W., and (for mail), 80 Glen Manor Drive, Toronto, Ont., Canada. JENNINGS, Warren G. (A 1930), Resident Vice- Pres. (for mail), Minneapolis-Honeywell Regu lator Co., 43 E. Ohio St., and 2738 Pine Grove Ave., Chicago, 111. JENNINS, Henry H. {Life Member; Af 1901), 15 Grange View, Chapeltown Road, Leeds, England. JENSON, Jean S. (Af 1912), Consulting Engr. (for mail), Neiler-Rich & Co., 431 S. Dearborn St., and 1634 West 106th St., Chicago, 111. JEPERTINGER, Richard C. (A 1934), Vice- Pres-Gen. Mgr. (for mail), Syncromatic Air Cond. Corp.. 1317 N. Third St., and 1628 W. Vienna St., Milwaukee, Wis. . JIMENEZ, Joaquin Gil (Af 1935), Engr. Director (for mail), Avda Menendez Pelayo, 19 Cuadrupdo and la misma Madrid, Spain. JOHN, Victor P. (Af 1931), Mgr., Buffalo Branch American Blower Corp., 822 White Bldg., and (for mail), 136 Berryman Drive, Snyder, N. Y. JOHNS, Harold B * (Af 1928; 7 1927), (for mail), Peoples Gas Light & Coke Co., 122 S. Michigan Ave., Chicago, and 543 N. Elmwood Ave., Oak Park, 111. JOHNSON, Allen J. (Af 1935), Director (for mail). Anthracite Institute Laboratory, Primos, Delaware Co., and 344 Congress Ave., Lans downe, Pa. JOHNSON, Carl W. (Af 1912), Pres, (for mail). C. W. Johnson, Inc., 211 N. Desplaines St. and 1809 Morse Ave., Chicago, III. JOHNSON, Clarence W. (Af 1933; A 1933; J 1931), Branch Mgr. (for mail), Canadian Sirocco Co.,-Ltd., 630 Dorchester St. W., and 333 Dresden Ave., Mt. Royal, Montreal, P. Q.. Canada. JOHNSON, Edward B. (Af 1919), Sales Engr.. Staten Island Supply Co., and (for mail), 154 Wardwell Ave., W. New Brighton, N. Y. JOHNSON, Edgar E. (Af 1926), Sales Engr. (for mail), Buffalo Forge Co., 490 Broadway, and 103 University Ave., Buffalo, N. Y. JOHNSON, Helge S. (A 1933; 7 1927), Dist. Mgr. (for mail), Buffalo Forge Co., 414 Standard Bldg., and 20 Fleetwood Ave., Albany, N. Y. JOHNSON, Leslie O. (7 1930), Engr.. C. A. Dunham Co., 30 Rockefeller Plaza. New York, and (for mail), c/o Y, M. C. A., White Plains, N. Y. . JOHNSON, Louis H. (Af 1931), 918 LaSalle Ave., Minneapolis, Minn. JOHNSON, Walter A. {S 1935), Asst. Instructor, Mech. Engrg. Dept, (for mail), 1138 John Jay Hall, Columbia University, New York, N. Y. JOHNSTON, Hugo D. (A 1934), Engr. and Contr., Box 282, Wellington, Qnt., Canada. . JOHNSTON, J. Ambler (Af 1912), Partner, Carneal Johnston & Wright, Electric Bldg., Richmond, Va. JOHNSTON, Robert E. (Af 1929; A 1926), Managing Dir. (for mail), R. E. Johnston Co., Ltd., 1070 Homer St., and 3342 West 33rd Ave., Vancouver, B. C.. Canada. JOHNSTON, William H. (Af 1924), 306 East 26th St., New York, N. Y. JONES, Alfred (Af 1928). Chief Consulting Engr. (for mail), Armstrong Cork Co., P. O. Box 540, and 402 President Ave., Lancaster, Pa. JONES, Alfred L. (Af 1926). Plbg. and Htg. Contr. (for mail), 431 Greenwich Ave., Green wich, and Breezemont Ave., Riverside, Conn. JONES, Allan T. (7 1935), Mech. Engr. (for mail), S. A. Armstrong. Ltd., 720 Bathurst St., and 325 Kingswood Road, Toronto, Ont., Canada. JONES, Andrew P. {S 1935), Elec, and Mech. Engr., Hereford, Texas. JONES, Bernard G. (Af 1928), Mgr. (for mail), Acme Fan & Blower Co., Ltd., 868 Arlington SL, and 542 Raglan Road, Winnipeg, Man., Canada, JONES, Charles R. (A 1928). Jones Supply Co., Siloam Springs, Ark. JONES, Edwin (Af 1933; .7 1924), Engr. and Estimator (for mail). Watt Plbg., Htg. & Supply Co., 608 S. Cincinnati, and 1436 East 17th Place, Tulsa, Okla. . JONES, Edwin A. (Af 1919), Chief Engr. (for mail), L. J. Mueller Furnace Co., 2001 W. Oklahoma, and 4065 Prospect, Milwaukee, Wis. JONES, Edwin F. (Af 1923), Consulting Engr., 922 New York Bldg., and (for mail), 220 Mont rose Place, St. Paul, Minn. JONES, Harold L. (Af 1920), Asst. Supt. (for mail), W. W. Farrier Co., 44 Montgomery St., Jersey City, and 11 Cambridge Road, Glen Ridge, N. J. JONES, Norman R. (A 1935). Sales Mgr., Orr & Sembower, Inc., Reading, and (for mail), 109 Rutledge Ave., Rutledge, Pa. JONES, Raymond E. (Af 1919), Asst. Supervisor, Fuel Oil Sales, Gulf Refining Co., 1515 Locust SL, Philadelphia, Pa., and (for mail), 39 West End Ave., Haddonfield, N. J. JONES, William T. (Af 1915), {Presidential Member), (Pres., 1933; 1st Vice-Pres., 1932; 2nd Vice-Pres., 1931; Council, 1925-1933), Treas., Barnes & Jones, 128 Brookside Ave., Jamaica Plain, and (for mail), 1886 Beacon St., Waban, Mass. JORDAN, Lebert E. (A 1934). Engr., Supervisor of Installation (for mail), Minneapolis Air Con . ditioner Co., 1609 Hennepin Ave., and 122 Arthur Ave. S.E., Minneapolis, Minn. - JORDAN, Richard C * (7 1935; S 1933). Air Cond. and Htg. Engr., Central Supply Co., 312 S. Third St., and (for mail), 2518 Grand Ave. S., Minneapolis, Minn. JORDAN, W. D. (Af 1935), Mgr., Air Cond. Div. (for mail). Savage Arms Corp., 100 East 42nd St., New York, and 132 Overlook Road, New Rochelle, N. Y. JOYCE, Harry B. (Af 1922), Consulting Engr. (for mail), 810 Commerce Bldg., and 501 Liberty St., Erie, Pa. JUNG, John S. (Af 1930; A 1923), Htg. Contractor (for mail), 2409 W. Greenfield Ave., and 1516 S. Layton Blvd., Milwaukee, Wis. JUTTNER, Otto J. (Af 1915). Pres, (for mail). Juttner Htg. Co., 814 N. Milwaukee St., and 910 E. Wells SL, Milwaukee, Wis. K KACZENSKI, Chester (7 1933), P. O. Box 147, Torrington, Conn. KAGEY, I. B., Jr.* (7 1929), Sales Engr. (for mail). Carrier Engrg. Corp., 404 Bona Allen Bldg., and Atlanta Athletic Club, Atlanta, Ga. KAISER, Fred (Af 1935), Branch Mgr. (for mail), Minneapolis-Honeywell Regulator Co., 45 Allen St., and 202 Winston Road, Buffalo, N. Y. KALINSKY, Alex G. (5 1934), 13706 Durkee Ave., Cleveland, Ohio. KAMMAN, Arnold R. (A 1925; 7 1921), (for mail), 493 Franklin St., Buffalo, and R. F. D.' 3, Lake Shore Road, Hamburg, N. Y. KAMPISH, Nick S. (7 1935; S 1934), Draftsman and Asst. Engr., Cooling & Air Cond. Corp., New York, N. Y., and (for mail), 214 E. Lincoln . Ave., Roselle Park, N. J. . 25 " of andAmerican Society Heating Ventilating Engineers Guide, 1936 KAPPEL, George W. A. (At 1921), Pres, and Treas. (for mail). Camden Heating Co., Wilson Blvd. and Waldorf Ave., Camden, and 347 W. Kings Highway, Haddonfield, N. J. KARGES, Albert (A 1935), Vice-Pres. and Managing Director, The James Stewart Mfg. Co., Ltd., and (for mail), 37 Perry St., Wood stock, Ont., Canada. KARLSON, Alfred F. (Af 1918), Chief Engr. (for mail), Parks-Cramer Co., 970 Main St., Fitch burg, and 186 Prospect St., North Leominster, Mass. _ KARLSTEEN, Gustav H. (Af 1935), Plant Engr., Dunlop Tire & Rubber Co., Buffalo, and (for mail). Box 55, Route 1, Tonawanda, N. Y. KARTOR1E, V. T. (7 1935; S 1933), Engr., York Ice Machinery Corp., 2700 Washington Ave., and (for mail), 2982 East 102nd St.. Cleveland, Ohio. ' ,,. KASTNER, George C. (7 1935; S 1933), Sales Engr., Phillips & Ibsen. Inc,, 69 S. Broadway, Nyack, and (for mail). 654 East 226th St., New York. N. Y. KAUFMAN, Charles W. (7 1935), Engr. (for mail). Carrier Engrg. Corp., 180 N. Michigan Ave., Chicago, 111., and NicholasviUe, Ky. KEEFE, Edmund T. (Af 1931), Pres, (for mail). Underground Steam Construction Co., 75 Pitts St., Boston, and 185 Commonwealth Ave., Chestnut Hill, Mass. KEENEY, Frank P. (A 1915), Pres., Keeney Publishing Co., 6 N. Michigan Ave., Chicago, 111. KEHM, Horace Stevens (Af 1928), Pres, (for mail), Kehm Bros. Co., 51 E. Grand Ave., and 5510 Sheridan Road, Chicago, 111. KELBLE. Frank R. (Af 1928). Vice-Pres. and Mgr. (for mail), Huffman-Wolfe Co. of Phila delphia, 11 W. Rittenhouse St., Philadelphia, and 115 Rosyln Ave., Glenside, Pa. KELL, Waldo R. (A 1934), Sales Engr. (for mail). The Marley Co., 1915 Walnut St., and 1107 West 49th St., Kansas City, Mo. KELLEY, James J. (A 1924), Vice-Pres. and Gen. Mgr. (for mail), Arthur H. Ballard, Inc., 535 Commonwealth Ave., Boston, and 142 Governors Ave., Medford, Mass. KELLNER, Day C. (5 1933), (for mail), Carnegie Institute of Technology, Pittsburgh, Pa., and Cuba City, Wis. KELLOGG, Alfred (Af 1916), (Council, 1920 1921; 1923-1924), Consulting Engr. (for mail), 585 Boylston St., Boston, and 6 Hawthorne St., Belmont, Mass. KELLY, Charles J. (Af 1931), New York Repr., Jas. P. Marsh Corp., 551 Fifth Ave., New York, and (for mail), 162 Fairview Ave., Jersey City, N. J. KELLY, John G. (A 1919), 374 Park Ave., Yonkers, N. Y. KELLY, Wilbur C. (Af 1935), Field Engr. (for mail). Iron Fireman Mfg. Co.. 602 King St. W., and 58 Elmsthorpe Ave., Toronto, Ont., Canada. KENDALL, Edwin H, (A 1932; 7 1930), Engr. (for mail), English-Lauer, Inc., 309 West 12th St., Los Angeles, and 1470 Poppy Peak Drive, Pasadena, Calif. KENNEDY, Maron (J 1930). Sales Engr. (for mail), York Ice Machinery Corp., 5051 Santa Fe Ave., and 2637 Bronson Ave., Los Angeles, Calif. KENNEDY, Owen A. (5 1933), Carnegie Institute of Technology, Pittsburgh, Pa. KENNEDY, Paul V. (5 1934), 105 Avon St., New Haven, Conn., and (for mail), 4915 Forbes St., Pittsburgh, Pa. KENT, J. King (7 1928), Pres, (for mail), J. King Kent & Co., Inc., 6327 Clayton Ave., and 530 N. Union, St. Louis, Mo. KENT, Laurence F. (A 1927; 7 1924). Pres, (for . mail), Moncrief Furnace Co., P. O. Box 1673, Atlanta, and R. F. D. No. 2, Smyrna, Ga. KENT, Richard L. (Af 1935), Dist. Mgr., Trane Co. of Canada, Ltd., Toronto, Ont., and (for mail), 31 Kennedy St., Winnipeg, Man., Canada. KEPLER, Donald A. (S 1934), Planning Dept., Gibbs & Cox. Inc., 11 Broadway, New York, N. Y., and (for mail), 30 Maplewood Ave., Maplewood, N. J. KEPLINGER, William L. (Af 1929), Special Repr. (for mail). Carrier Engrg. Corp., 408 Chrysler Bldg., New York, and 103 Sunset Drive, Hempstead, L. I., N. Y. KEPPNER, Harry W. (Af 1930), (for mail), H. W. Keppner, 1310 South 56th Ave., and 1245 S. Austin Blvd., Cicero, 111. KERN, Raymond T. (Af 1927), Chief Engr., Jennison Co., Fitchburg, and (for mail), 51 Claflin SL, Leominster, Mass. KERSHAW, Melville G. (Af 1932; A 1926; 7 1921), Vtg. and Air Cond. Engr. (for mail). E. I. Du Pont de Nemours & Co., Wilmington, Del., and 7313 North 21st St., Philadelphia, Pa. KEYES, Robert E. (Af 1913), Chief Engr., The Cooling & Air Conditioning Corp., 24 Damon St., Hyde Park, Boston, Mass. KEYS, Lee Faria (S 1934), Asst. Air Cond. Engr., Metropolitan Life Insurance Co., 1 Madison Ave., New York, N. Y.f and (for mail), Route 1, Box 366, Phoenix, Ariz. K1CZALES, Maurice D. (Af 1935), Assoc. Mech. Engr., U. S. Army Motion Picture Service, State War and Navy Bldg., and (for mail), 3000 Connecticut Ave. N.W., Washington, D. C. KIEFER, Carl J. (Af 1922), Consulting Engr. (for mail), 918 Schmidt Bldg., and 984 Lennox Place, Cincinnati, Ohio. KIEFER. E. J., Jr. (A 1932; 7 1928), Treas. and Gen. Mgr. (for mail), H. C. Archibald Co., 8 S. Sixth St., and 108 N. Sixth St., Stroudsburg, Pa. KIESLING, Justin A. (Af 1930), Pres, (for mail). Robischung Kiesling, Inc., 4848 Main St., P. O. Box 1295, and 1806 Holman Ave., Houston, Texas. .,v KILNER, John S. (Af 1929), Prop, (for mail), Kilner Co., 427 Stormfeltz-Lovely Bldg., and 1091 Seminole Ave., Detroit, Mich. KIMBALL, Charles W. (Af 1915), Richard D. Kimball Co., 6 Beacon St.. Boston, Mass. KIMBALL, Dwight D.* (Af 1908), (Presidential Member), (Pres., 1915; 2nd Vice-Pres., 1914; Board of Governors, 1912-1916), Consulting Engr. (for mail). Room 1728 Grand Central Terminal Bldg., and 307 East 44th SL, New York, N. Y. KING, Roy L. (S 1933), 2538 Clinton Ave. S., Minneapolis, Minn. . KINGSLAND, George D. (Af 1935), Vice-Pres. (for mail), Minneapolis-Honeywell Regulator Co.. 2747 Fourth Ave. S., and 2124 Girard Ave. S., Minneapolis, Minn. KINGSWELL, William E. (Af 1935). Pres, (for mail), W. E. Kingswell, Inc., 3707 Georgia Ave. N.W., and 2739 Macomb St. N.W., Washington, D. C. KIPE, J. Morgan (Af 1919), 801 Homestead Ave., Beecbwood, Del. Co., Pa. KIRK,'Charles D. (Af 1909), Mgr. (for mail), Chas. D. Kirk Co., Sargent & Colleen, and 774 McMillan Ave., Winnipeg, Man., Canada. KIRKPATRICK, Arthur H. (Af 1935; 7 1931), Salesman, Ilg Electric VenL Co., 415 Brainard, and (for mail). Hotel Webster Hall, Detroit, Mich. KITAURA, Shigeyukl (Af 1918), 191 Shimo- ohsaki, near Tokyo, Japan. KITCHELL, Herbert N. (A 1926), Retired, 4528 Circle Ave., Cincinnati, Ohio. KITCHEN, Francis A. (A 1927; 71923), Pres, (for mail), American Wanning & Ventilating Co., 1514 Prospect, and 2077 Campus, Cleveland, Ohio. KITCHEN, John H. (Af 1906), Owner (for mail), John H. Kitchen Co., 1016 Baltimore Ave., and 5015 Westwood Terrace, Kansas City, Mo. KLEIN, Albert (Af 1920), Managing Director (for mail), Lufttechnische Gesellschaft m b H. Stuttgart W., Konigstrasse 84, and Stuttgart N., Panoramastr. 23, Germany. 26 Roll of Membership KLEIN, Edward W. (Af 1917), S. E. Dist. Mgr. (for mail), Warren Webster & Co., 152 Nassau St. N.W., and 456 Peachtree Battle Ave., Atlanta, Ga. KLIE, Walter (Af 1915), Pres, (for mail). The Smith & Oby Co., 6107 Carnegie Ave., Cleveland, and 18411 S. Woodland Ave., Shaker Heights, Ohio. RNIBB, Alfred E. (Af 1930), Htg. Engr. (for mail), L. L. McConachie Co., 1003 Maryland Ave., and 9333 E. Jefferson Ave., Detroit, Mich. KNOPF, Charles (7 1935; 5 1933), 1201 Liberty Ave., Brooklyn, N. Y. KNOWLES, Mahlon G. (Af 1935), Instructor in Applied Science, Wentworth Institute, 550 Huntington Ave., Boston, and (for mail), 255 Burrill St., Swampscott, Mass. KNOX, James R. (Af 1930), Htg. Engr., James Combe & Son, Ltd., 33 King St., Dundee, and (for mail), 9 Union SL, Newport, Fife, Scotland. KNUDTSON, Carl M. (5 1935), 2410 Cromwell Drive, Minneapolis. Minn. KOCH, Harry O. (Af 1916). 212 Centre SL, Tamaqua, Pa. KOCH, Richard G. (A 1935), Supervisor of Househeating and Air Cond., Milwaukee Gas Light Co., 626 E. Wisconsin Ave., and (for mail), 734 North 34th St.. Milwaukee, Wis. KOHLER. Walter J., Jr. (A 1933). Htg. Sales Supervisor (for mail). Kohler Co., and 605 W. Park Lane, Kohler, Wis. KONZO, Seichi* (7 1932), Special Research Associate. University of Illinois, 214 Mech. Engr. Lab., and (for mail), 1108 W. Stoughton St., Urbana, 111. KOOISTRA, John F. (Af 1933), Engr. (for mail). Carrier, 748 E. Washington, and 6063 Roy St., Lo3 Angeles, Calif. KORN, Charles B. (Af 1922), Member of Firm, Reber-Kom Co., 817 Cumberland SL, and (for mail). 1022 S. Eighth SL, Allentown, Pa. KOTTCAMP, Horace A. (Af 1915), Mgr., Kottcamp Construction Co., 147 N. Second SL, and 527 Philadelphia Ave., Chambersburg, Pa. KOZU, Tamiichlro (Af 1930). Chief Engr. (for mail). Japan Radiator Industrial Assn., 506 Marunouchi Bldg., and 1701 Yonchome Shimoochiai, Yodobashiku, Tokyo, Japan. KRAMIG, Robert E., Jr. (A 1933), Vice-Pres. Treas. (for mail), R. E. Kramig & Co., Inc., 222-4 East 14th SL, Cincinnati, and 51 Central Terrace, Wyoming, Ohio. KRATZ, Alonzo P.* (Af 1925), Research Prof, (for mail), DepL of Mech. Engrg., University of Illinois, and 1003 Douglas Ave., Urbana, 111. KREISSL, Hans George (Af 1925), Mgr.. Vento DepL (for mail), American Radiator Co., 816 S. Michigan Ave., Chicago, and 408 Lee SL, Evanston, 111. KRENZ, Alfred S. (A 1935), Sales Mgr. (for mail), Krenz & Co., 5114 W. Center SL, and 4315 W. Lisbon Ave., Milwaukee, Wis. KREZ, Leonard (A 1935), Secy, (for mail), Paul J. Krez Co., 444 N. LaSalle St., and 4716 N. Paulina St., Chicago, 111. KRIBS, Charles L. Jr. (Af 1935), Consulting Mech. Engr.,- Kribs & Landauer, 807 South western Life Bldg., and (for mail), 4209 Shenan doah Ave., Dallas, Texas. KRIEBEL, Arthur E. (Af 1920), Sales Engr. (for mail), Haynes Selling Co., 1518 Fairmount Ave., Philadelphia, and Chester Co., Berwyn, Pa. KRUEGER, James I. (M 1921). Mfrs. Repr., Illinois Engrg. Co., Whitlock Coil Pipe Co. (for mail), 357 Ninth SL, and 1920 Sacramento SL, . San Francisco, Calif. KRUSE, Robert W. (A 1930), Kruse Co.. 353 West 16th Place. Indianapolis, Ind. KUEHN, Walter C. {A 1933), Kueho Htg. & Vtg. Co., 915 Seventh Ave. S., Minneapolis, Minn. KUEMPEL, Leon L. (7 1929), MinneapolisHoneywell Regulator Co., 101 Marietta SL Bldg., Atlanta, Ga. KUHLMANN, Rudolf (Af 1928), 122 East 42nd St., New York, N. Y. KUNS, Joseph W. (5 1935), 2110 Hawthorne Ave., Minneapolis. Minn. KWAN, I. K. (Af 1933). Gen. Mgr., China Engi neering Co., 30 Brenan Road, Shanghai, China. KYLBERG, V. C. (A 1934), Owner, Mgr., Contr., Engr., 607 Ridgewood Road, Maplewood; N. J. KYLE, W. J. (A 1935), Power Sales Engr. (for mail), Byllesby Engrg. & Management Corp., 231 S. LaSalle St., and 1220 Jarvis Ave., Chicago, L LAGODZINSKI, H. J. (A 1927; 7 1920). 3628 N. Tripp Ave., Chicago, 111. LANDAUER, Leo L. (7 1932), Mech. Engr. (for mail), Kribs & Landauer, Consulting Engra., 807 Southwestern Life Bldg., and 5707 Velasco, Dallas, Texas. LANDERS, John J. (Af 1930; A 1924; 7 1924), Htg. Engr. and Mfgrs. Agent (for mail), 303 Crosby Bldg., and 823 Smith St., Buffalo, N. Y.' LANE, D. Duffy (Af 1934), Mortgage Commission Servicing Corp., 346 Broadway, New York, and (for mail), 147-14-24th Ave., Whitestone, L. 1., N. Y. LANGE, Fred F. (A 1934), Engr. (for mail). Mechanical Service Co., 905 Metropolitan Life Bldg., Minneapolis, and Route 3, Box 80, Excelsior, Minn., Lake Minnetonka, Minn. LANGENBERG, Everett B. (Af 1914), (Council, 1926*1931), Pres, (for mail), Langenberg Htg. Co., 3800 W. Pine Blvd., and 6031 Enright, St. Louis, Mo. LANNING. E. K. (A 1927), Asst. Secy, and Sales Mgr. (for mail), Warren Webster & Co., Camden and Clayton, N. J. LANOU, J. Ernest (Af 1931), Mgr. (for mail), 90 St. Paul St., and 48 Brookes Ave., Burlington, Vt. LARSON, Gustus L.* (Af 1923), (1st Vice-Pres., 1935; 2nd Vice-Pres., 1934; Council, 1929-1935), Prof., Steam and Gas Engrg., and Chairman of DepL of Mech. Engrg., University of Wisconsin, Madison, Wis. ,, LaSALVIA, James J (Af 1930), Mech. Engr., Frigidaire Corp., and (for mail), Emerson Court Apt. No. XI, 1845 Emerson Ave., Dayton, Ohio. LAUER, Harold B. (Af 1930), Vice-Pres. (for mail), English & Lauer, Inc., 309 West 12th SL,' and 1121 S. Hayworth Ave., Los Angeles, Calif. LAUTENSCHLAGER, Fred (Af 1915), VicePres-Treas. (Office and Factory), 100 Reichert Ct., Racine, Wis., and (for mail), 3846 Alta Vista Terrace, Chicago, 111. LAUTERBACH, Henry, Jr. (Af 1935), AssL Chief Engr. (for mail). Carrier Engrg. Corp., 2022 Bryan SL, and 5818 Edison Court, Dallas, Texas. LAWLOR, John J. (Af 1935), Mgr., Htg. Div.. The James Robertson Co., Ltd., 215 Spadina Ave., and (for mail), 35 Tennis Cres., Toronto, Ont., Canada. LAWLER, Matthew M. (7 1930), Res. Mgr. (for mail), Hitchen Engrg. Co., Inc., Ill W. Washing ton St., and 6900 N. Ashland Blvd., Chicago, 111. LAWTON, Frank C. (Af 1928), 145 Buena Vista Ave., Hawthorne, N. J. LEDNUM, J. Maynard (Af 1934), Engr., Silica Gel Corp., and (for mail), 4203 Linkwood Road, Baltimore. Md. LEEK, Walter (Af 1903), Managing Director (for mail). Leek & Co., Ltd., 1111 Homer St., and 4769 W. Second Ave., Vancouver, B. C., Canada. LEES, Herbert K. (Af 1924: 7 1912). (for mail), William Lees, Inc., 548 W. Washington Blvd., and 5855 N. Kenneth Ave., Chicago, 111. LEGLER, Frederick W. (Af 1935; A 1933). Mgr., City Office (for mail). Waterman-Waterbury Co., 1121 Jackson SL N.E., and 2919 Johnson SL N.E., Minneapolis, Minn. LEILICH, Roger L. (Af 1922), Pres, (for mail), Baltimore Heat Corp., 2000 W. Pratt SL, and 2810 Elsinor Ave., Baltimore, Md. 27 American Society of Heating and Ventilating Engineers Guide, 1936 LEINROTH, J. Paul (Af 1929), Gen. Industrial Fuel Repr. (for mail). Public Service Electric 8c Gas Co., 80 Park Place, Newark, and 37 The Fairway, Montclair, N. J. . LEITCH, Arthur S. (Af 1908), Pres, and Manag ing Director (for mail). The Arthur S. Leitch Co., Ltd.. 1123 Bay St., and 421 Russell Hill Road, Toronto, Ont~, Canada. LELAND, Warren B. (Af 1929), Sales Engr., The H. B. Smith Co., Westfield, and 34 Leyfred Terrace, and (for mail), P. O. Box 1522, Spring field, Mass. LELAND, William E. (M 1915), Partner (for mail), Leland and Haley, 58 Sutter St., San Francisco, and 704 The Alameda, Berkeley, Calif. LENNON, Joseph O. (Af 1929), Mgr. (for mail), Ilg Electric Vtg. Co., 15 Park Row, and 180 West 59th St., New York, N. Y. LEONARD, J. H. (Af 1931), Mgr. (for mail), C. A. Dunham Co., Ltd., 508 Scott Bldg., and 844 Grosvenor Ave., Winnipeg, Man., Canada. LEOPOLD, Charles S. (Af 1934), Consulting Engr. (for mail), 213 S. Broad St., Philadelphia, and 614 Elkins Ave., Elkins Park, Pa. LESLIE, Donald E. (S 1933), Exp. Engrg. Lab., University of Minnesota, and (for mail), 3541 Bloomington Ave., Minneapolis, Minn. LEUPOLD, Herbert W. (J 1933), Engr., Metro politan Life Insurance Co., 1 Madison Ave., New York, and (for mail), 82-23 Ankener Ave., Elmhurst, L. I., N. Y. LEVENTHAL, Bernard (S 1935), Sales Engr., Schwerin Air Cond. Corp., 507 Lexington Ave New York, and (for mail), 3913-13th Ave., Brooklyn, N. Y. LEVERANCE, Herbert J. (A 1935), Salesman, J. M. O'Connor Co., 434 N. Rock Island, Wichita, Kans., and (for mail), 1838 Northwest Uth St., Oklahoma City, Okla. LEVY, Marion I. (J 1931), Sales Mgr. and C. Engr. (for mail). Air Controls, Inc., Div. of Cleveland Heater Co., 1933 West 114th St., and 1273 West 108th St., Cleveland, Ohio. LEWIS, Carroll E. (Af 1930). Zone Mgr.. Air Cond. and Commercial Div,, Frigidaire Corp., 300 Taylor St., and (for mail), 1660 Catalpa Drive, Dayton, Ohio. LEWIS, George C. (Af 1919), Vice-Pres. and . Treas. (for mail), American Heating & Venti lating Co., 1505 Race St., Philadelphia, and 812 Summit Grove Ave., Bryn Mawr, Pa. LEWIS, John G. (Af 1926), 412 East 31st St., Kansas City, Mo. LEWIS, L. Logan* (Af 1918), Secy, (for mail). Carrier Engrg, Corp., 850 Frelinghuysen Ave., Newark, and 724 Carlton Ave., Plainfield, N. J. LEWIS, Samuel R.* (Af 1905), (Presidential Member), (Pres., 1914; 2nd Vice-Pres., 1910; Board of Governors, 1909-1910-1912; Council,. 1914-1915), Consulting Engr. (for mail), 407 ' S. Dearborn St., and 4737 Kimbark Ave., Chicago, 111. LEWIS, Thornton* (Af 1919), (Presidential Member), (Pres., 1929;.1st Vice-Pres., 1928; 2nd . Vice-Pres., 1927; Council, 1923-1930), Executive Vice-Pres. (for mail). Carrier Engrg. Corp., 850 Frelinghuysen Ave., Newark, and 156 Irving Ave., South Orange, N. J. LIBBY, Ralph S. (/ 1933). Air Cond. Engr., Arthur S. Leitch Co., Ltd., 1123 Bay St., and (for mail), 275 Winona Drive, Toronto, Ont., Canada. LICHTY, Charles P. CM 1920), Pres, (for mail). C. P. Lichty Engrg. Co., Inc., 400H South 21st St., and 125 Windsor Drive, Birmingham, Ala. LIGHTHART, Charles H. (M 1935), Mfrs. Sales Engr. (for mail), 254 Court St., and 19 E. Winspear Ave., Buffalo, N. Y. LINCOLN, Roland L. (Af 1935), Engr., Hoffman Specialty Co., and (for mail), 487 Farmington Ave., Waterbury, Conn. LINDBERG, Arthur F. (J 1935; 5 1933), Assoc. Engr. (for mail), U. S. Dept, of Inspector, National Park Service, 300 Keelihe Bldg., Omaha, Nebr., and 1484 Van Buren St., St. Paul, Minn. LINGO, Charles K. (J 1935), Air Cond. Engr., Florida Power & Light Co., Miami, Fla. LINN, Homer R. (M 1914), Consulting Engr., 321 S. Ashland Ave., LaGrange, 111. LINSENMEYER, Francis J. (M 1935), Prof., Mech. Engrg. (for mail). University of Detroit, Livemois & McNichols, and 17375 Prairie Ave., Detroit, Mich. LINTON, John P. (Af 1927), Vice-Pres. and Managing Director (for mail). The Garth Co., 50 Craig St. W., and 247 Brock Ave. N., Mon treal W., P. Q., Canada. LITTLE, Kenneth B. (A 1935), Sales Engr. (for mail). The Brownell Co., 736 Dixie Terminal Bldg., and 2132 Crane Ave., Cincinnati, Ohio. LIVAR, Allen P. (M 1935), Mgr., Mech. Equip. Div., Reynolds Corp., 19 Rector St., New York, and (for mail), 830 Bronx River Road, Bronx- ville, N. Y. - LIVINGSTON, Bernard B. (Af 1927), Gas Sales Engr., Metropolitan Edison Co., and (for mail). P. O. Box 118, Easton, Pa. LLOYD, Edward C. (Af 1927). (for mail), Arm strong Cork & Insulation Co., and 429 W. Walnut St., Lancaster, Pa. LOCKE, Robert A, (Af 1935), Mgr., Steel Heating Boiler Institute, and (for mail), 500 N. Union St., Middletown, Pa. LOCKHART. Harold A. (J 1935), Engr. (for mail). Bell & Gossett Co.. 3000 Wallace St., and 7906 S. Carpenter St., Chicago, 111. LOEFFLER, Frank X. (Af 1914), Pres, (for mail). Frank LoeJHer Supply Co., 710 N. Hudson St., and 320 West 26th St., Oklahoma City, Okla. LOEFFLER, Louis, Jr. (S 1934), 1815 W. Ninth St., Oklahoma City, Okla. LOFTE, John A. (S 1933), Asst. Engr., Pflugradt Co., 215 W. Kilboum Ave., and (for mail), 2305 W. Wisconsin Ave., Milwaukee, Wis. ' LOGAN, Thomas M. (S 1935), 330 North St., Murphysboro, and (for mail), 108 N. Romine St., Champaign, 111. LOH, Nan-Shee (Af 1933; A 1931: J 1927), Mgr.. New Shanghai Htg. & Plbg. Co., Room 302 National Commercial Bank Bldg., Lane 200. Peking Road, Shanghai, China. LONG, David Raymond (Af 1927), Pres., Tagcraft Corp., 142 S. Christian St., and (for mail), 150 School Lane, Lancaster, Pa. LONG, Wayne E. (Af 1935), Assoc. Prof, of Mech. Engrg., Texas Agricultural & Mechanical College, College Station, Texas. LONGCOY, Grant B. (Af 1933), Maintainance Engr., Cleveland Board of Education, and (for mail), 1462 Wyandotte Ave., Lakewood, Ohio. LOO Ping Yok (Af 1933), Gen. Mgr. (for mail), China Engrg. Co., 774 North Chung San Road, Nanking, and 271-273 Dumbarton Road. Tientsin, China. LOVE, Clarence H. (Af 1919), Mfrs. Agent, Nash Engrg Co., 317 Chamber of Commerce, and (for mail), 289 Norwalk Ave., Buffalo, N. Y. LOWT^SBERY, Benjamin F. (Af 1920), Htg. Engr., Benjamin F. Shaw Co., P. O. Box 953, and (for mail), 21 S. Sycamore St., Wilmington, Del. LUCK, Alexander W.* (Life Member 1934; Af 1919) Pres, and Gen. Mgr. (for mail), Reading Heater & Supply Co., Church and Woodward Sts., Reading and Reiffton, Pa. LUCKE, Charles E. (M 1924), Stevens Prof .of Mech. Engrg. (for mail), Columbia University, Pupin Physics Laboratories, and X86 Riverside Drive, New York, N. Y. LUND, Clarence E. (/ 1935; S 1933), Warm Air Htg. Inspector, Minneapolis Bldg. Dept., 213 City Hall, and (for mail), 2729-18th Ave.. S., Minneapolis, Minn. LUTY, Donald J. (Af 1933), Asst. Mgr. Air Cond. Div. (for mail). Gar Wood Industries, Inc., 7924 Riopelle St., Detroit, and .911 Forest Ave., Ann Arbor, Mich. LUTZ, James H., Jr. (Af 1928), Owner (for mail), 140 Paxton St., and 1601 Forster St., Harrisburg, Pa. . 28 Roll of Membership LYLE, Ernest T. (Af 1919), Vice-Pres. and Dist. Mgr., Carrier Engrg. Corp., 408 Chrysler-Bldg., New York, N. Y. LYLE, J. I.*.(Af 1911), (Presidential Member), MAHON, B. B. (Af 1935), Principal, School of Air Cond. (for mail). International Correspondence Schools, Ash St. and Wyomihg Ave., and 433 Fig St., Scranton, Pa. (Pres., 19l7i Council, 1917-1918), Pres, (for mail). Carrier Engrg. Corp., 850 Frelinghuysen Ave., Newark, and 1200 W. Seventh St., Plain field, N. J. LYMAN, Samuel E. (A 1924), Engr., Carrier Engrg. Corp., 850 Frelinghuysen Ave., Newark, N. J. LYNCH, William L. (Af 1928), Treas-Gen. Mgr. (for mail), Rome Turney Radiator Co., Canal St., and 1413 N. George St., Rome, N. Y. LYNN, John H. (A 1933), 3431 Shenandoah St., Dallas, Texas. LYON, P. S. (Af 1929), Air Cond. Dept, (for mail). General Electric Co., 5 Lawrence St., Bloomfield, and 42 Hawthorne Place, Summit, N. J. LYONS, Cornelius J. (A 1932), Sales Engr. (for mail), Nash Engrg. Co., Wilson Ave., and 22 Haviland St., South Norwalk, Conn. LYONS, Michael A. (Af 1935), Htg. Contr., 435 West 36th St., New York, N. Y. MAHONEY, David J. (Af 1930; A 1926), Branch Mgr. (for mail),- Johnson Service Co., 503 Franklin St., and 99 Delham Ave., Buffalo, N. YV . MAIER, George M. (Af 1921), Asst, to Vice-Pres. and Gen. Mgr. of Mfg. (for mail), American Radiator Co., 8007 Jos Campau, Detroit, Mich. MAILLARD, Albert L. (Af 1934). Head of Air Cond. Div. (for mail), Kansas City Power & Light Co., 1330 Baltimore, 3740 Washington, Kansas City, Mo. MALLIS, William (Af 1914), 330 Lyon Bldg., Seattle Wssh * MALONE, Dayle G. (Af 1929; A 1925), Branch Mgr., Petroleum Heat & Power Co., 1725 S. Michigan Ave., and (for mail), 7315 Merrill Ave., Chicago, 111. MALVIN, Ray C. (Af 1929), Pres, (for mail). Malvin & May, Inc., 2427 S. Michigan Ave., ana 8220 Dante Ave., Chicago, 111. MANAHAN, James E. (Af 1934), Air Cond. Engr. (for mail), (Kelvinator Div.), Witte Hardware M Co., 704 N. Third St., and 3455a Utah Ave., MACCUBBIN, Howard A. (Af 1934), Buyer of Htg. Equip., Montgomery Ward 8c Co., Chicago, and (for mail), 2135 Ridge Ave., Evanston, 111. MacDADE, Ambrose H. (Af 1923), Sales (for mail), Burnham Boiler Corp., S. E. Cor. 31st and Jefferson Sts., Philadelphia, Pa., and 225 Haddon Ave., Westmont, N. J. MACDONALD, Donald B. (Af 1930), Mgr., C. A. Dunham Co., 101 E. Walnut, St. Kingston, Pa. MacDONALD, Douglas J. (Af 1935), Vice-Pres. (for mail). Dominion Radiator Boiler Co., Ltd., 1322 Dufferin St., and 96 Hudson Drive, Toronto, Ont., Canada. - St. Louis, Mo. MANDEVILLE, Edgar W. (Af 1914), 1171 East 37th St., Brooklyn, N. Y. MANN, Arthur R. (Af 1930), Owner (for mail), Mann & Co., 721 R. W. Bldg., and 122 West 15th St., Hutchinson, Kan. MANN, Lee B. (J 1930), Air Cond. Engr. (for mail), Carrier Engrg. Corp., 12 South 12th St.. ' Philadelphia, and 3018 Garrett Road, Drexel Hill. Pa. MANNING, Walter M. (Af 1930), Htg. Engr.. , Crane Co., 115 E. Front St., Grand Island, and (for mail), P. O. Box 112, Clarks, Nebr. MACDONALD, Everett A. (A 1933), Branch MARIN, Axel* (Af 1935), Assoc. Prof., Mech. Mgr. (for mail). Spencer Heater Co., 145 Broad Engrg. (for mail). University of Michigan, 241 way. Cambridge, and 154 Standish Road, Water W. Engrg. Bldg., and P. O. Box 175, Ann Arbor, town, Mass. Mich. ' MACHEN, James T. (/ 1934), Chicago Branch Mgr. (for mail). The RicWil Co., Ill W. Monroe St., and 420 Diveraey Pkwy., Chicago, III. . MACHIN, Donald W. (J 1935). Fuel Engr., Pittsburg & Midway Coal Mining Co., 810 Dwight Bldg., Kansas City, Mo., and (for mail), 2029 Vermont St., Lawrence, Kan. MACK, Ludwig (Af 1935), Dist. Mgr., Cooling & ' Air Cond. Corp., Cresmont and Haddon Aves., Camden, N. J., and (for mail), 246 W. Upsal St., Germantown, Pa. MacKENZIE, John J. (Af 1925), 664 Shaw St., Toronto, Ont., Canada. MacLEOD, Kenneth F. (A 1933), Mgr., Htg. Dept., Crane Co., 419 Second Ave. S., and (for MARKS, Alexander A. (A 1930), Asst. Sales Mgr., Richmond Radiator Co., 2241 N. Ameri can St., Philadelphia, and (for mail), 6635 McCallum St., Germantown, Philadelphia, Pa. MARKUSH, Emery U. (Af 1931). Mech. Engr. (for mail), 225 East 21st St., New York, and 8442-85th Road, Woodhaven, L. I., N. Y. MARRINER, John M. S. (Af 1934), Vice-Pres. (for mail), Taylor Engrg. & Construction Co., Ltd., 14 King St. E., and 111M Balsam Ave., Toronto, Ont., Canada. MARSCHALL, Peter J. (Af 1930; A 1930; J 1927), Engr., Kroeschell Engrg. Co., 215 W. Ontario St., and (for mail), 2201 W. Touhy Ave., Chicago, 111- mail), 7703 First Ave. N.E., Seattle, Wash. MARSHALL, William Dewey (Af 1935). Branch MacMILLAN, Alexander R. (Af 1935), Air Mgr. (for mail), Noland Co., Inc., P. O. Box 762, Cond. Div., Frigidaire Corp., and (for mail), Rosslyn, and 1307 N. Wakefield St., Ballston, Va. 52 Constance Ave., Dayton, Ohio. MARSHALL, H. Hall (Af 1923), 37 West 43rd St., MACRAE, Robert B. (J 1935), Air Cond. Engr., New York, N. Y. E. J. Nell Co., Manila, P. I. MADDUX, Oliver L. (Af 1935; A 1933), Chief Engr., United Gas & Fuel Co. of Hamilton, Ltd., MARTENIS, John V. (Af i918). Assoc. Prof., University of Minnesota, and (for mail), 4800 Bloomington Ave., Minneapolis, Minn. 88 King St. E., and (for mail), 18 Whitton Road, Hamilton, Ont.. Canada. MADISON, Richard D. (Af 1926), Research ' Engr. (for mail), Buffalo Forge Co., 490 Broad way, and 133 Lisbon Ave., Buffalo, N. Y. MAEHLING, Leon S. (Af 1932). Supervisor Sales. Equitable Gas Co., 427 Liberty Ave., and (for mail). 448 Sulgrave Road, Pittsburgh, Pa. MAGINN, Peter F. (Life Member; M 1908), Mfrs. Agent, P. F. Maginn & Co., 207 Fulton Bldg., and (for mail), 1140 S. Negley Ave., Pittsburgh, Pa. MARTIN, Albert B. (Af 1917). Kewanee Boiler Co., 1858 S. Western Ave., Chicago, 111. MARTIN, George W.* (Af 1911), Supervising ` Engr. (for mail), U. S. Realty & Improvement Co., Ill Broadway, New York, N. Y., and 340 Prospect St., Ridgewood, N. J. MARTINEZ, Juan J. (J 1929), Research and Rate Engr., Mexican Light & Power Co., Ltd., Gante 20, and (for mail), Paseo de la Reforma 183, Mexico City, Mexico. . MaGIRL, Willis J. (Af 1934; A 1931; J 1927). MARTINKA, Paul D. < 1934), 13703 Chautau- Chief Engr. (for mail), P. H. MaGirl Foundry & gua Ave., Cleveland, Ohio; Furnace Works, 401-13 E. Oakland Ave., and 108' MARTOCELLO, Joseph A. (Af 1934), Pres.. Warner Ave., Bloomington, 111. Jos. A. Martocello & Co., 229 North 13th St., MAGNEY, Gottlieb R, (Af 1931), Pres, (for mail). Philadelphia, Pa. Magney & Tusler, Inc.. Archts. and Engrs., 104 S. Ninth St., and 5329 Washburn Ave. S., Minneapolis, Minn. - MARTY, Edgar O. (Af 1916). Pres, and Gen. Mgr., Indian Head Anthracite, Inc., and (for mail), 1775 Howard Ave., PottsviUe, Pa. 29 American Society of Heating and Ventilating Engineers Guide, 1936 MARUM, Otto (Af 1931). Plant Engr., Agfa Ansco Corp., 29 Charles St., and (for mail). 12 Grand Blvd.; Binghamton, N. Y. MATCHETT, James C. (Af 1923). Vice-Pres. and Gen. Mgr. (for mail), Illinois Engrg. Co., 21st and McCONACHIE, Lome L. (A 1928), Htg. and Pibg., 1003 Maryland Ave., and (for mail), 1379 Maryland Ave., Detroit, Mich. McCONNER, Charles R, (A 1925; J 1922), Gen. Sales Mgr. (for mail). Clarage Fan Co., and 1904 Racine Ave., and 9936 S. Winchester Ave., Chicago. 111. MATHER, Harry H. (A 1929), Promotional Analysis Secy, (for mail), Philadelphia Electric Waite Ave., Kalamazoo, Mich. McCORMACK, Denis (Af 1933), Mgr., Air Cond. Dept, (for mail), Julien P. Friez & Sons, Inc., 4 N. Central Ave., and 5924 Bellona Ave., Co., 1000 Chestnut SL, Philadelphia, and 373 Lakeview Ave., Drexel Hill, Pa. MATHEY, Nicholas J. (Af 1915), Mathey Plbg. & Htg. Co., 31 Third Ave. N.E., Le Mars, Iowa. MATHIS, Eugene* (Af 1922), (for mail). New York Blower Co., 32nd St. and Shields Ave., Baltimore, Md. McCOY, Thomas F. (M 1924), Mgr. (for mail). The Powers Regulator Co., 125 St. Botolph St., Boston, and Glen Road, Wellesley Farms, Mass. McCREERY, Hugh J. (Af 1922), (for mail), Marine Bldg., and 1617-49th Ave. W., Van Armour P. O. Sta., and 9151 S. Hoyne Ave., couver, B. C., Canada. McCRlMMON, A. Murray (A 1935). Asst. Secy, Chicago, 111. MATHIS, Henry (Af 1921), The New York Blower Co., 32nd and Shields Ave., and (for (for mail). Hydro Electric Power Commission, 620 University Ave., Toronto 2, and 83 Glen - mail), 10317 Oakley Ave., Chicago, 111. MATHIS, Jullen W. (A 1921), New York Blower Co., 32nd St. and Shields Ave., Chicago, 211. MATTHEWS, John E. (Af 1934; A 1934), DisL Mgr., B. F. Sturtevant Co., 1106 Commerce Bldg., and (for mail), 5642 Lydia St., Kansas City. Mo. MATZEN, Harry B. (Af 1919), (for mail), York Ice Machinery Corp., 42nd St. and Second Ave., and Hotel St. George, Clark St. at Henry, - Brooklyn, N. Y. MAUTSCH, Robert (A 1928), Engr., Managing Director (for mail), Compagnie Beige Des Freins Westinghouse, 97 Ave. Louise, Brussels, Road, Toronto, Ont-, Canada. McCUNE, Byron V. (Af 1928), Sales Engr. (for mail), 301 W. Yakima Ave., P. O. Box 385, and 2310 W. Yakima Ave., Yakima, Wash. McDonald, Thomas (A 1931), Mgr. (for mail), Minneapolis-Honeywell Regulator Co., Ltd., 117 Peter St., and 56 Kingsway, Toronto, Ont., Canada. McDonnell, Everett N. (Af 1923), Pres, (for mail), McDonnell & Miller, Wngley Blag., Chicago, and Georgian Hotel, Evanston, 111. McDOWELL, Bert W. (J 1935), Air Cond. Engr. (for mail). Consolidated Engineers, Inc., 56 Main St_, Springfield, and Community Y. M. C. A., Belgium. MAWBY, Pensyl (Af 1934), Service Engr., West Springfield, Mass. McELGIN, John W. (/ 1931), 180 Rowland Park. Lehigh Navigation Coal Co., 143 Liberty St., New York. N. Y., and (for mail), 748 Center St., Cheltenham, Pa. McFARLAND, William P. (A 1923), 1258 Pratt River Edge, N. J. MAXWELL, George W. (Jf 1935; 5 1932). Supt- Engr., Kenealy &. Maxwell, Box 447, and (for mail). Box 422, Harwich Port, Mass. MAY, Clarence W. (Af 1933), Consulting Engr. (for mail), 422 Smith Tower, and 902 W. Hala- day. Seattle, Wash. MAY, Edward M. (if 1931), Combustioneer, Inc., 1825 S. Michigan Ave., Chicago, and (for mail), 1022 N. Hayes Ave., Oak Park, 111. MAY, George Elmer (Af 1933), Air Cond. Engr. (for mail). New Orleans Public Service, Inc., 317 . Baronne St., and 2031 Short St., New Orleans, L*. MAY, James W. (J 1935). Asst. Prof., H. V. Sc A. C. (for mail). College of Engrg., University of Blvd., Chicago, 111. . McGAUGHEY, John R., Jr. U 1935), Air Cond. Eagr. (for mail). Carrier Engrg. Corp., 408 Chrysler Bldg., New York, N. Y., and Hold Winfield Scott, Elizabeth, N. J. McGINNESS, J. E. (Af 1903), Pres, (for mail), McGinness, Smith 8c McGinness Co., 527 First Ave., and 142 Bellfield Ave., Pittsburgh, Pa. McGONAGLE, Arthur (Af 1932), Consulting Engr. (for mail), 1013 Fulton Bldg., Pittsburgh, and 6815 Prospect Ave., Ben Avon, Pa. McGRAlL, Thomas E. (Af 1926), Mgr., Htg. Dept., Crane, Ltd., Beaver Hall, and (for mail), W. A. 9087, 3465 Belmore Ave.. Montreal, P. Q., Canada. McGUlGAN, L. A. (A 1919), 724 Hastings St., Kentucky, and 1701 S. Limestone St., Lexington, Ky. MAY, Maxwell F. (Af 1929), Secy-Treas. (for mail), Malvin & May, Inc., 332 S. Michigan Pittsburgh. Pa. McHENRY, Robert W. (Af 1921). Engr., Trans. Canada Radiator & Boiler Co., 672 Dupont St., and (for mail), 236 Eglinton Ave., Toronto, Ont., Ave., Chicago, and Palos Park, III. MAYETTE. Charles E. (Af 1926). 1400 Floral St., Washington, D. C. MAYNARD, Herbert R. (S 1935), 58 North llth St., Minneapolis, Minn. MAYNARD, J. Earle (Af 1931), Chief Htg. Engr., Fox Furnace Co., and (for mail), Telegraph Road, Elyria, Ohio. McCAULEY, James H. (Af 1921), Pres, (for mail), J. H. McCauley, Inc., 5558 West 65th St, Chicago, and 707 William St., River Forest, 111. McCLELLAN, James E. (Af 1922), Mgr. (for mail), American Blower Corp., 228 N. LaSalle St., Chicago, and 8844 LaCrosse Ave., Niles * Center, 111. McCLlNTOCK, Alexander, Jr. (M1928; J1920), Canada. MclLVAlNE, John H.* (Af 1929), Pres, (for mail), Mcllvaine Burner Corp., 663 W. Washington Blvd., and 1100 Lake Shore Drive, Chicago, IU. MclNTlRE, James F. (Af 1915; A 1914), (Coun cil, 1926-1928; 1932-1935), Vice-Pres. (for mail), U. ,S. Radiator Corp., 1056-44 Cadillac Square, P. O. Box 686, and 3261 Sherbourne Road, Detroit, Mich. McINTOSH, Fabian C. (Af 1921; J 1917), (Council, 1929-1931; 1933-1935), Branch Mgr. (for mail), Johnson Service Co., 1238 Brighton Road, and 302 Marshall Ave., Pittsburgh, Pa. McKIEVER, William H* (Life Member; M 1897; J 1896). Pres, (for mail), William H. McKiever, Inc., 247 West 13th St., New York, and 479 Member of Firm (for mail), A. McClintock & Sons, 1937 Ridge Ave., and 121 Rochelle Ave., Wissahicken, Pahiladelphla, Pa. ' Eighth St., Brooklyn, N. Y. ' McKINLEY, Carroll B. (5 1934), Sales Engr., New York Lipman Corp., 1716. Main St., McCLlNTOCK, William (Af 1935). Supervising Engr., Dept, of Parks, 37-43 West 65th St., and (for mail), 2 N. Pinehurst Ave., New York, N. Y. Buffalo, N. Y. McKINNEY, William J. (A 1934), Mgr., Atlanta Dist., American Blower Corp., 716-101 Marietta McCLOUGHAN, Charles (S 1934), 14 Cottage St. E., Norwalk, Conn., and (for mail), 279 Ryereon St., Brooklyn, N. Y. McCOLL, Jay R.* (Af 1916), (Presidential . Member), (Pre9., 1922; 1st Vice-Pres, 1921; 2nd Vice-Pres., 1920; Council, 1920-1923), 2304 Penobscot Bldg., Detroit, Mich. St. Bldg.. Atlanta, Ga. McKITTRICK, Percy A. (A 1934), Treas. and Gen. Mgr. (for mail), Parks-Cramer Co., 970 Main St., and 219 Blossom St., Fitchburg, Mass. MCLAREN, F. S. (J 1935). Air Cond. Engr., Frigidaire Corp., 4436 Toulouse St., and (for mail), 5209 Pitt St., New Orleans, La. 30 Roll of Membership McLARNEY. Harry W. (Af 1933). Air Cond. Engr. (for mail). Union Electric Light & Power Co., 315 North 12th Blvd., and 5053 Lindenwuod Ave., St. Louis, Mo. McLAUGHLIN, Joseph D. (A 1930; j 1928). Owner (for mail), Braley & McLaughlin, 166 Aborn St., and 45 Roslyn Ave., Providence, R. I. McLEAN, Dermid (Af 1917), McColl-Snyder & McLean, 2304 Penobscot Bldg., Detroit. Mich. McLEISH, William S. (A 1932; J 1928). Dist. Engr. (for mail). The Ric-Wil Co., Room 1838. 101 Park Ave., and 500 Riverside Drive, New York, N. Y. McLENEGAN, David W.* (Af 1933), Asst. Engr., Air Cond, Dept, (for mail). General Electric Co., 5 Lawrence St., Bloomfield, and 73 Arlington Ave., Caldwell, N. J. McLOUTH, Bruce F. (J 1934), Chief Engr., Heater Div. (for mail), Dail Steel Products Co., Lansing, and 135 Gonson St-, East Lansing, Mich. McMAHON, Thomas W. (Af 1928). Dist. Mgr. (for mail), American Blower Corp., 1715 Railway Exchange Bldg., and 6151 Waterman Ave., St. Louis, Mo. ' McMUNN, A. H. (5 1934), (for mail), 4915 Forbes St., Pittsburgh, Pa., and 311 St. Clair St-, Clarksburg, W. Va. McMURRER, Louis J. (Af 1928; A 1928; J 1924). Pres., The McMurrer Co., 303 Congress St., Boston, and (for mail), 190 Harvard Circle, Newtonville, Mass. McNAMARA, William (A 1930), Sales Engr. (for mail). The Trane Co., 2694 University Ave., and 1355 Como Ave. W., St. Paul, Minn. McPHERSON, WUllam A. (Af 1929), Chief, Htg. and Vtg. Div., Dept, of School Bldgs., 11 Beacon St.. Boston, and (for mail), 86 Dwinnell St-, West Roxbury, Mass. McQUAID, Daniel J. (M 1934), Engrg. Service (for mail), 614 Cooper Bldg., and 1565 Mil waukee St., Denver, Colo. McTERNAN, Felix J. (A 1931), 1523 Main SL. Buffalo, N. Y. MEAD, Edward A. (Af 1926), Asst. Sales Mgr. (for mail), Nash Engrg. Co., and 5 Thames St., Norwalk, Conn. MEAKIN, John B. (J 1935), Sales Engr. (for mail), Richardson & Boynton, Holderness. N. H. MEARS. Leon A.* (J 1935), 1918 Lakeshore Ave.. Oakland, Calif. . MERRILL, Frank A. (Af 1934), Consulting Htg. and Vtg. Engr. (for mail), .H0IH3 French, 210 South St.. Boston, and 19 Auburndale Road, Marblehead, Mass. MERRITT, C. J. (Af 1925), Director, Merritt, Ltd., 8 French Bund, Shanghai, China. MERTZ, Walter A. (Af 1919), Kehm Bros.. 51 E. Grand Ave., Chicago, 111. MERWIN, Glle R. (Af 1924; J 1923), Secy., Rockford Plbg. Supply Co., and (for mail), 1325-20th SL, Rockford, lit. MEYER, Charles L. (Af 1930), 198-25 Foothill Terrace, Hollis, L. I., N. Y. MEYER, Frank L. (Af 1932; J 1928), Vice-Pres.. The Meyer Furnace Co., and (for mail), 9 Cole Court, Peoria. III. MEYER, Henry C., Jr.* (Af 1898), (Council, 1915-1916), Pres, (for mail), Meyer Strong & Jones, Inc., 101 Park Ave., New York, N. Y., and 25 Highland Ave., Montclair. N. J. MEYER, John W. (A 1929), Asst, to Mgr., Industrial Sales DepL (for mail), Philadelphia Electric Co., 1000 Chestnut St., and 5000 Pine St., Philadelphia, Pa. MICHIE, D. Fraser (A 1930). Engrg. Sales DepL. Crane, Ltd., 93 Lombard St., and (for mail), 5 B, 553 Wardlaw Ave., Winnipeg, Man., Canada. ' MIDDLETON, Howard A. (A 1935), Prop., Middleton Electric Co., 514 S. Ohio SL, Sedaha, Mo. MILES. James C. (Af 1914), DepL Mgr. (for mail), The Henry Furnace & Foundry Co., 3471 East 49th St., and 1863 Crawford Road, Cleve land, Ohio. MILLAR, Rowland J. (Af 1925), Mgr. (for mail). Pease Foundry Co., Ltd., 227 Victoria Sl, and 53 Oakmount Road, Toronto, Ont., Canada. MILLARD, Junius W. (Af 1929), Dist. Mgr. (for mail). Carrier Engrg. Corp., 888 Asylum Ave., Hartford, and Manchester, Conn. . MILLER, Bruce R. (Af 1935; A 1930), Engr. and Estimator, Renz Engrg. & Equipment Co., 307 Terminal Bldg., and (for mall), 1533 N.W. 25th SL, Oklahoma City, Okla. MILLER, Charles A. (A 1917), Salesman (for mail). The H. B. Smith Co., 10 East 41st SL, and 2870 Marion Ave., New York, N. Y. MILLER, Charles W. (Af 1919; J 1908), (for., mail). The Rado Co.. 338 S. Second St., Mil MEFFERT, George H. (J 1930), Engr. (for mail). Carrier Engrg. Corp., 2022 Bryan St., and waukee, and R. 1, Box 42, Menomonee Falls, Wis. 4154)4 Prescott Ave., Dallas, Texas. MILLER, Edgar R. (A 1935). Chief Engr. (for MEHL, Oscar H. (J 1935). Estimating Engr. (for mail), Winnipeg Cold Storage, and Suite O mail). Carrier Engrg. Corp., 180 N. Michigan Bexley Court, Winnipeg, Man., Canada. Ave., and 7416 Phillips Ave., Chicago, IU. MILLER, Floyd A. (M 1911), 377 U. S. Court MEHNE, Carl A. (Af 1929). Htg. and Vtg. House, Chicago, 111. Expert (for mail). Room 821, 101 Park Ave., New York, and Livingston SL, Valhalla,-N. Y. MILLER, Harold A. {S 1935), 1009-24th Ave. S.E., Minneapolis, Minn. MEINKE, Howard G. (Af 1933), Asst. Engr., Civil Engrg. Dept, (for mail). New York Edison . Co., Room 1517-S, 4 Irving Place, New York, and 41 Harte St., Baldwin, Nassau Co., N. Y. MEISEL, Carl L. (J 1931), 350 Central Park W., New York, N. Y. MILLER, Harry M. (Af 1920), 3938 N. StoweU Ave.. Milwaukee, Wis. MILLER, James E. (Af 1914; J 1912), Htg. Contr., 2210 Colfax SL, Evanston, 111. MILLER, John F. G. (Af 1916), Vice-Pres. (for MELLON, JamesT. J. (Afx1911), (Council, 1915), (for mail). Mellon Co., 4415-21 Ludlow St., and 431 North 63rd Sl, Philadelphia, Pa. MENDEN, Peter J. (Af 1935). Asst. Sales Mgr.. Htg. Div., Young Radiator Co., and (for mall), 1509 Arthur Ave., Racine, Wig. MENSING, Frederick D. (Af 1920), (National * Treas., 1931-1932; Council, 1931-1932), Con sulting Engr., 2845 Frankford Ave., Phila delphia, Pa. MERKEL, Fred P. (Af 1924), 204-11th Ave.. Belmar, N. J. mail), B. F. Sturtevant Co. Hyde Park, Boston, and 20 Chapel St., Brookline, Mass. MILLER, Leo B. (Af 1926), Salesman, Refrigera tion Div. (for mail), Minneapolis-Honeywell Regulator Co., 801 Second Ave., New York, and 133 Pondfield Road, Bronxville, N. Y. MILLER, Lester L. (5 1935), 623-14th Ave., Minneapolis, and (for mail), 2127 Tenth Ave., Hibbing, Minn. MILLER, Prof. Lorin G. (Af 1933). Head. DepL of Mecb. Engrg. (for mail), Michigan State College, R. E. Olds Hall, and 525 Albert SL, East Lansing, Mich. MERLE, Andre (Af 1934), Director of Engrg.* Control Corp. of America, 250 West 57th Sl, New York, N. Y., and (for mall), 172 Lincoln Ave., Elizabeth, N. J. MERRILL, Carl J. (Af 1919), Treas. (for mail). C. J. Merrill, Inc., 54 St. John 'St., and 15 Longfellow St., Portland, Maine. MILLER, Meri W. (Af 1932; A 1932; J 1926), Mgr. of Lab. (for mail), Trane Co., and 333 North 23rd St., LaCrosse, Wis. MILLER, Robert A* (Af 1931). Tech. Sales Engr. (for mail), Pittsburgh Plate Glass Co., 2200 Grant Bldg., Pittsburgh, and 1211 Carlisle St., Tarentum, Pa. ' 31 American Society of Heating and Ventilating Engineers Guide, 1936 MILLER, Robert E. (J 1035), Sales-Engr. (for mail). American Radiator Co., 1344 Broadway, and 18264 Birchcrest Drive, Detroit, Mich. MILLER, Robert T. (A 1927), Chief Engr. (for mail). Masonite Corp., Ill W. Washington St.. Chicago, and 1228 Sunnyside Ave., Chicago ' Heights, 111. MILLER, ToJbert G. (A 1929; J 1921), SupU Htg. and Vtg., and (for mail), 11 N. Second St., . Wormleysburg, Pa. MILLIKEN, James H* (Af 1923), Dist. Repr. (for mail), American Air Filter Co., Inc., 20 N. ; Wacker Drive, Chicago, and 1021 Ridge Ct~, Evanston, 111. MILLIKEN, Vincent D. (A 1930), Sales Mgr. (for ' mail), Skidmore Corp., and 2015 Forres Ave., St. Joseph, Mich. MILLIS, Linn W. (Life Member 1934; M 1918), Secy., Security Stove & Mfg. Co., 1630 Oakland, and (for mail), 3534 Wabash Ave., Kansas City. Mo. MILLS, HartzeU C. (A 1935), Sales, Htg., Minne apolis Gas Light Co., and (for mail), 4609 Blaisdell Ave., Minneapolis, Minn. MILWARD, Robert K. (A 1920). Mgr. (for mail), U. S. Radiator Corp., 127 Campbell Ave., and - 2441 Calvert Ave., Detroit, Mich. MINER. Major H. (5 1934), 1510J* N.W., 25th St., Oklahoma City, Okla. MITCHELL, C. H. (Af 1924), Engr., The Fels Co.. 42 Union St., Portland, Maine, and (for mail), 179 Thatcher St., Milton, Mass. MITTENDORFF, E. M. (Af 1932), Sales Engr., Sarco Co., Inc., 222 N. Bank Drive, Chicago, and (for mail), 956 Greenwood Ave., Winnetka, 111. - MJOLSNES, Leonard O. (S 1935), 618-15th Ave. S.E., Minneapolis, Minn. ' MODIANO, Rene (Af 1925), 55 Blvd. Beausejour, Paris 16, erne, France. MOELLER, Robert (5 1935), 3256 East 119th St., Cleveland, Ohio. MOHRFELD, Herbert H. (J 1935), Air Cond. Engr. (for mail), Mohrfeld Engrg Co., Lees and Atlantic Aves., Collingswood, and B-102 Haddon Manor, Haddonfield,' N. J. MOLER, William H. (M 1927; J 1923), Branch Supervisor, Comm. Div., York Ice Machinery Corp., 2225 S. Lamar St., Dallas, and (for mail), R. F. D. 1, Box 37-B, Irving, Texas. MONDAY, Charles E. (M 1920), Chas. E. Mon day & Co., 1323 Fairmount Ave., Philadelphia, Pa. MONIER, Kurt A. J. (5 1935), 135 Ligustrum Drive, and (for mail), A. J. Monier & Co., 1446 N. Flores, San Antonio, Texas. MONROE, Raymond R. (A 1929), Draftsman, Bullard Co., Canfield St., and (for mail), 258 Maplewood Ave., Bridgeport, Conn. MONTGOMERY, Ora C. fAf 1933), Asst. Supt. of Power (for mail). New York Central Railroad, Room 1842, Grand Central Terminal, and 255 . West 84th St., New York, N. Y. MOODY, Lawrence E. (Af *1919), Member of Firm (for mail). Moody & Hutchison, 1701 Architects' Bldg., Philadelphia, Pa., and 237 Jefferson Ave., Haddonfield, N. J. MOON, Frank L. (A 1935), Utilization Engr.. Los Angeles Gas & Electric Corp., 810 S. Flower St., Los Angeles, and (for mail), 1264 Ruberta Ave., Glendale. Calif. MOON, L. Walter (M 1915), (Council, 1933 1935), Pres. (for mail), Bradiley Heating Co., 3834 Olive St., and 5006 N. Kingshighway, St. Louis, Mo. ' MOORE, C. Herbert (J 1935), Efficiency Mgr., Congress Hotel Co., Chicago, and (for mail), 6 College Campus, Lake Forest, 111. MOORE, H. Carlton (M 1935). Instr. in Mech. Engrg. (for mail), Massachusetts Institute of Technology, Cambridge, and 145 Beaumont Ave., Newtonville, Mass. MOORE, H. Lee (Af 1919), Mgr., Buffalo Forge ' Co., 912 Fulton Bldg., Pittsburgh, Pa. MOORE, Henry W. (M 1935), Mgr., Air Cond. Dept, (for mail), Frigidaire Corp., 4436 Toulouse St., and 912 Harding Drive, Apt. A, New Orleans, La. MOORE, Herbert S. (A 1923), Distr. Repr., Iron Fireman Mfg. Co. of Canada, Ltd., 602 King St. W., and (for mail), 107 Clendenan Ave., Toronto, Ont., Canada. MOORE, Robert E. (J 1933), Junior Sales Engr. (Div. of). Manning Maxwell & Moore, 446 Communipaw Ave., Jersey City, N. J., and (for mail). 1730 East 46th St., Brooklyn, N. Y. MOORE, R. Edwin (A 1928), Vice-Pres. in charge of Sales, Bell & Gossett Co., 3000 Wallace St., Chicago, and (for mail), 714 Brummel St., Evanston, 111. - MOREAU, Donato (A 1932), 35 E. McCormick, Tucson, Ariz. MORGAN, Glenn C. (Af 1911), Partner (for mail), Morgan-Genish Co., 307 Essex Bldg., and 4308 Fremont Ave. S., Minneapolis, Minn. MORGAN, Robert C. (M 1915), 314 W. Seymour, . St., Philadelphia, Pa. MOREHOUSE, H. Preston (Af 1933), General Air Cond. Repr. (for mail). Public Service Elec. & Gas Co., 80 Park Place, Newark, and 85 Halsted St.. East Orange, N. J. MORRIS, Arnold M. (/ 1934), Sheet Metal Worker, Philadelphia Navy Yard, Sheet Metal Shop Building No. 17, and (for mail), 3022 Baltz St., Philadelphia, Pa. MORRIS, Fred H. (A 1929), 14704 Strathmore Ave., East Cleveland, Ohio. MORRISON, Chester B. (Af 1931), Mgr, (for mail). York Shipley Co., 81 Jinkee Road, and 347 Route Cohen, Shanghai. China. MORSE, Clark T. (Af 1913), Pres, (for mail), American Blower Corp., 6000 Russell, and 16222 Shaftsbury Road, Detroit, Mich. MORSE, Floyd W. (A 1934), (for mail), Chamber lin Metal Weather Strip Co., 52 Vanderbilt Ave., New York, and 112 Sycamore Ave., Mt. Vernon, MORTON, Charles H. (A 1931), 1106 Sherman St. S.E., Grand Rapids, Mich. MORTON, Harold S. (Af 1931). Sales Engr., Sutherland Air Cond. Corp., 385 Minnesota St., St. Paul, and (for mail), 4330 Wooddale Ave., Minneapolis, Minn. MOSHER, Clarence H. (A 1919), C. H. Mosher Co., 423 Ashland Ave., Buffalo, N. Y. MOSS, Edward (Af 1920), Way and Structure Dept, (for mail). New York Rapid Transit Corp., 385 Flatbush Ave. Ext., Brooklyn, and 9053-204th St.. Hollis, L. I., N. Y. ' MOTZ, O. Wayne (Af 1932), Mech. Engr., Samuel Hannaford & Sons. Archts., 1024 Dixie Terminal Bldg., Cincinnati, and (for mail), 2587 Irving Place, Norwood, Ohio. . MOULDER, Albert W * (Af 1917), Vice-Pres. (for mail). Grinnell Co., Inc., 260 W. Exchange St., and 12 Blackstone Blvd., Providence R. I. . MOULTON, David (Af 1926), 99 Chauncy St., Boston, Mass. . MOZLEY, Raymond G. (/ 1935), 119 N. Poplar St., and (for mail), 323 Piedmont Bldg., Char-, lotte, N. C. . MUELLER, Harold C. (A 1930), Sales Engr. (for mail). Powers Regulator Co., 2720 Greenview Ave., Chicago, and 2720 Lawndale Ave., Evans ton, IU. . 'MULLEN, Thomas J., Jr. (/ 1935), Sales Engr. (for mail), B. F. Sturtevant Co., 708 Mills Bldg., ' . Washington, D. C. MUNDER, John F., Jr. (Af 1927; J 1924), (for mail). Quinn Engrg. Co., 501 Madison Ave., New York, N. Y., and 81 Joyce Road, Tenafly, N. J. MUNIER, Leon L. (Af 1919; J 1915), Pres, (for mail), Wolff & Munier, Inc., 222 East 41st St., New York, and 63 Columbia Ave.,' Hartsdale, N. Y. MUNN, E. Fit* (Af 1935), Designing Engr. (for mail). Over & Munn, 903 McArthur Bldg., and 65 Berrydale Ave., Winnipeg, Man., Canada. 32 Roll of Membership MUNRO, Edward A. (Charier Member; Life Member), Htg. and Vtg. Engr., 49 N.W. Terrace, Miami. Fla. MUNSON, James L. (A 1935), Instr. (for mail), Pratt Institute, 215 Ryersdn St., and 381 Carlton Ave., Brooklyn, and 15 Parkwold . Drive W., Valley Stream, L.-1., N. Y. MURPHY, Charles C. (S 1934), 2766 Woodhull Ave., New York. N. Y. MURPHY, Edward T.* (Af 1915), Vice-Pres. (for mail). Carrier Engrg. Corp., 180 N. Michigan Ave., Room 907, and 200 E. Chestnut St., Chicago. 111. . MURPHY, Howard C * (Af 1923), Vice-Pres. (for mail). American Air Filter Co., Inc., 215 Central Ave.. and 495 Lightfoot Road, Louisville, Ky. MURPHY, Joseph R. (Af 1934; A 1925), VicePres., Taco Heaters, * Inc., 342 Madison Ave., New York, N. Y., and (for mail), The Terrace, Riverside, Conn. MURPHY, William W. (M 1930), Treas. (for mail), W. W. Murphy Co., 424 Worthington St., and 25 Mansfield St., Springfield, Mass. MURRAY, John J. (A 1933), Vice-Pres., Pierce Perry Co., 236 Congress St., Boston, and (for , mail), 60 Commonwealth Park W., Newton Centre, Mass. MURRAY, Thomas F. (Af 1923), State Architect and (for mail), 14 S. Lake Ave., Albany, N/Y. MUSGRAVE, Merrill N. (A 1935), Pres, (for mail), Harrison Sales Co., 314 Ninth Ave. N., and 1005 E. Roy, Seattle, Wash. MYERS, Charles R. (S 1935), White Bear Lake, Route No. 2, Minneapolis, Minn. NELSON, Raymond A. (5 1935), Resident Engr., Minnesota and Ontario Paper Co., and (for mail), 927 Riverside Drive, International Falls, Minn. ' NELSON, Richard H. (A 1933: J 1928), Secy- Treas., Herman Nelson Corp:, 1824 Third Ave., and (for mail), 1303-30th St., Moline, 111. NESBITT, Albert J.* (Af 1921; J 1921), Secy- Treas. (for mail), John J. Nesbitt, Inc., State Road and Rhawn St., Philadelphia, and 304 Evergreen Road, Jenkintown, Pa. NESBITT, John J. (Af 1923). John J. Nesbitt, Inc., State Road and Rhawn St., Holmesburg, Philadelphia, Pa. NESDAHL, Eilert (Af 1915), c/o Colben Nesdahl, Route 1, Shevlin, Minn. NESS, William H. C. (Af 1931). Gen. Mgr. (for mail). Master Fan Corp., 1323 Channing St., and 215 N. Kingsley Drive., Los Angeles, Calif. NESSI, Andre (Af 1930), Ingr. des Arts et Manu factures, Expert pres le Tribunal Civil de le Seine (for mail), 1 Ave. du President Wilson, Paris (XVI), France. NEU, Henri J. E. (Af 1933), Pres., Etablissements Neu, 47-49 Rue Fourier, Lille (Nord), France. NEWCOMB, Lionel B. (J 1933). Junior Engr., Philadelphia Electric Co., and (for mail), 6056 Walton Ave., Philadelphia, Pa. NEWPORT, Charles F * (Af 1906), Sales Engr., Weil-McLain Co., Michigan City, Ind., and (for mail), 10001 Longwood Drive, Chicago, 111. NICELY, John E. (A 1925), Salesman, American Radiator Co., and (for mail), 1208 Marion St., Reading, Pa. MYERS, Frank L. (Af 1933), Sales Engr., Owens- NICHOLLS, Percy* (Af 1920), Supervising Engr., Illinois Glass Co., 965 Wall St., and (for mail), 3406 Detroit Ave., Toledo, Ohio. MYERS, George W. F. (Af 1930; A 1928; J 1923), Mfrs. Repr., Myers Engrg. Equipment Co., 3947 W. Pine Blvd., St. Louis, and (for mail), 476 Pasadena Ave., Webster Groves, Mo. `N .. NAROWETZ, Louis L., Jr. (Af 1929; A 1912), Secy, (for mail), Narowetz Htg. & Vtg. Co., 1711 Maypole Ave., Chicago, and 112 S. Park Ave., Park Ridge, 111. NASS, Arthur F. (Af 1927), Secy-Treas. (for mail), McGinness, Smith &'McGinness Co., 527 First Ave., Pittsburgh, and Elmhurst Road, R. D. No. 8, Crafton, P. O., Pa, - NATKIN, Benjamin* (Af 1909; J 1907), Pres, (for mail), Natkin & Co., 2020 Wyandotte, and 5211 Rockhill Road, Kansas City, Mo. NAYLOR, Charles L. (Af 1931), Supt., Heat, Light and Power (for mail), The Atlantic Refining Co., 3144 Passyunk Ave., and 2315 North 18th St., Philadelphia, Pa. NEALE, Laurance I. (A 1927), Vice-Pres. (for mail), Atlantic Gypsum Products Co., 60 East 42nd St., and 125 East 57th SL, New York, N. Y. NEEDLER, J. H. (Af. 1933), Phillips Getschow Co., 32 W. Austin Ave., Chicago, 111. NEILER, Samuel G. (Af 1898), Consulting Mech. - and Elec. Engr. (for mail), Neiler, Rich & Co., 431 S. Dearborn St., Chicago, and 737 N. Oak Park Ave., Oak Park, III. . NEIS, Willard A. (5 1935),. 5538 Forbes St., Pittsburgh, Pa. NELSON, Chester L. (J 1929), 6704 Oconto Ave. N,, Chicago, 111. . Fuel Section (for mail), U. S. Bureau of Mines, Pittsburgh, Pa. NIGHTINGALE, George F. (A 1931), Western Sales Mgr., Tuttle & Bailey, Inc., 61 W. Kinzie St., Chicago, and (for mail), 621 S. .Maple Ave., Oak Park, III. NOBBS, Walter W. (Af 1919), Consulting Engr., 100 Victoria St., London, S.W. 1, and (for mail), 50 Fairhazel Gardens, London N.W. 6, England.. NOBIS, Harry M. (Af 1914), 1827 Stanwood Road. E. Cleveland, Ohio. NOLL, William F. (Af 1924), Htg. Contr., 2850 North 47th St., Milwaukee, Wis. NOORD, Donald F. (5 1935). 5549 Forbes St., Pittsburgh, Pa. NORRIS, William D. (M 1930), 1314 Forest Ave., Wilmette, 111. NORTHON, Louis (Af 1929), Consulting Engr., 132 Park Ave., Mt. Vernon, N. Y. NOTTBERG, Gustav (A 1933), Secy, (for mail). U. S. Engineering Co., 914 Campbell, and 1835 East 68th St. Terrace, Kansas City, Mo. NOTTBERG, Henry (Af 1919), Vice-Pres. (for mail), U. S. Engineering Co., 914 Campbell St., and 213 S. Bales, Kansas City, Mo. ' NOVOTNEY, Thomas A. (Af 1928), Asst, to Gen. Mgr., Sales, National Radiator Corp., 221 Central Ave., and (for mail), 403 Wayne St., Johnstown, Pa. . NOWITZKY, Herman S. (A 1931), Supt., Construction Repairs and Maintenance, Wilmer & Vincent Theatrical Circuit, and (for mail), 151 Tenth St., Norfolk, Va. NUSBAUM, Lee* (Af 1915), Owner (for mail). Pennsylvania Engrg. Co., 1119-21 N. Howard St., Philadelphia, and 315 Carpenter Lane, Germantown, Philadelphia, Pa. NELSON, D. W.* (Af 1928). Asst. Prof, of Steam and Gas Engrg. (for mail), Mech. Engrg. Bldg., o University of Wisconsin, and 3906 Council Crest, Madison, Wis. NELSON, George O. (Af 1923), Engr., Carstens Bros., Ackley, Iowa. ` NELSON, Harold A. (Af 1926), 236 S. La Pere St., Beverly Hills, Calif. . OAKEY, William E. (Af 1932), Consulting Engr., Oriskany, N. Y. . OAKS, Orion O. (Af 1917), Executive Engr., American Radiator Co., 40 West 40th St., New York, N. Y., and (for mail), 119 Oak Ridge Ave.,' Summit, N. J. NELSON, Herman W. (Af 1909), Pres, (for mail). The Herman Nelson Corp., 1824 Third Ave., and 2500-11th St., Moline, fil. OATES, Walter A. (Af 1931), Htg. and Industrial . Engr., Lynn Gas & Electric Co., 90 Exchange St., and (for mail), 285 Lynn Shore Drive, Lynn, Mass. 33 American Society of Heating and Ventilating Engineers Guide,. 1936 O'BANNON, Lester S.* (Af 1928), Univereity of Kentucky, Lexington, Ky. OBERG, Harry C. (A 1933), Mgr*. Engrg. Dept., Crane Co., Fifth and Broadway, and (for mail), 1362 W. Minnehaha St., St. Paul, Minn. OBERT, Casin W.* (Af 1916), ConsulUng Engr., Union Carbide & Carbon Research Lab., 30 East 42nd St., New York, and (for mail), 122 N. Columbus Ave., Mt. Vernon, N. Y. O'BRIEN, J. H. (Af 1923), 228 N. LaSalle St., Chicago, 111. O'BRIEN, Walter N. (A 1935), Secy, and Treas. (for mail), O'Brien Equipment Co., 2726 Locust St., and 2221 Thurman Ave., St. Louis, Mo. O'CONNELL, Presly M. (Af 1916), Resident Engr., Inspector, P. W. A., and (for mail), College Court Apts., Pullman, Wash. OFFEN, Ben (Af 1928), Owner (for mail), B. Offen 1 -& Co., 608 S. Dearborn St., and 1100 N. Dear born St., Chicago, III. OFFNER, Alfred J.* (Af 1922), (National Treas.. 1935; Council, 1935), Consulting Engr. (for mail), 139 East 53rd St., New York, and 160-15-llth Ave.,Beechhurst, L. I., N. Y. O'GORMAN, John S., Jr. (A 1934), Mgr., Detroit Branch Office (for mail), Johnson Service Co., 427 Brainard St., and 775 Kennesaw Ave., Birmingham, Mich. OK.E,.William C. (/ 1934), Air Cond. Engr. (for mail). Sheldons, Ltd., 96 Grand Ave., Galt, and 1200 Richmond St., London. Ont., Canada. OLCHOFF, Maurice (Af 1933), Mgr., Olchoff Engrg. Co., 423 Dwight Bldg., and (for mail), 5341 Holmes, Kansas City, Mo. OLSEN, Carlton F. (A 1925; J 1920), Combustion Engr., Kewanee Boiler Corp., 1858 S. Western Ave., and (for mail), 10227 Aberdeen St., Chicago, 111. OLSEN, Gustav E. (M 1930), 6809 Amstel Blvd.. Arverne, L. I., N. Y. OLSON, Barney (A 1929), Mfrs. Repr., 122 S. - Michigan Ave., Chicago, and (for maU), 5724 N. Natoraa Ave., Norwood Park, 111. OLSON, Gilbert E. (Af 1930), 440 Ward Pkwy., Kansas City, Mo. OLSON, Robert G. (Af 1923), Sales Engr., American Blower Corp., 401 Broadway, New York. N. Y. OLVANY, William J. (Af 1912), Pres, (for mail), William J. Olvany, Inc., 100 Charles St., New York, and 109-40-71st Road, Forest Hills, L. J., N. Y. O'NEIL, Joseph M. (A 1934), 332 Common wealth Ave., Springfield, Mass. O'NEILL, James W. (M 1929: A 1927; J 1925), Chief Engr., Trane Co. of Canada, Ltd., 439 King St. W., and (for mail), 8 Springmount Ave., Toronto, Ont., Canada. O'NEILL, Peter (Af 1920), Treas. (for mail), Bartley-O'Neill Co., 240*42 Blvd. of Allies, Pittsburgh, and 2448 Charles St., Pittsburgh, Pa'. OPPERMAN, Everett F. (J 1935; 5 1933), Estimator, F. Opperman; Railroad Ave., and (for mail), 169 Milbank Ave., Greenwich, Conn. OREAR, Andrew G. (Af 1930), Sales Engr. and Mfrs. Repr. (for mail). Room 501 San Fernando Bldg., and 406 S. Main St., Los Angeles, Calif. O'REAR, Lawrence R. (Af 1934), Pres, (for mail), Midwest Plbg. & Htg. Co., 2450 Blake St., and 3033 West 37th Ave., Denver, Colo. OSBORN, Wallace J. (A 1927), Vice-Pres., Keeney Publishing Co., Grand Central Terminal Bldg., New York, N. Y., and (for mail), 599 Old Post Road, Fairfield, Conn. OSBORNE, Gurdon H. (Af 1922), Gen. Mgr.. The Ventilating & Blow Pipe Co., Ltd., 714 St. Maurice St., Montreal, and (for mail), 836 Pratt Ave., Outremont, Montreal, P. Q., Canada. OSBORNE, Maurice M. (Af 1925), 367 Beacon St., Boston, Mass. OSTERLE, William H. (Af 1934), Service * Supervisor, West Penn Power Co., 14 Wood St., Pittsburgh, and (for mail), 1028 Woodberry Road, New Kensington, Pa. OSTRIN, Albert (S 1935), 1216 James N., Minneapolis, Minn. ' OTIS, Gerald E.* (Af 1922), Vice-Pres. (for mail). The Herman Nelson Corp., and 1921-23rd Ave., Moline, 111. OTT, Oran W. (Af 1925), (Council. 1934-1935), Consulting Mech. Engr. (for mail), 422 Washing ton Bldg., and 123 S. Virgil Ave., Los Angeles, Calif. OTT. Rush C. (Af 1931). Sales Engr., Refrig erating Equip. Corp., 927 N. Meridian St., Indianapolis, Ind. OURUSOFF, L. S. (Af 1931). Engr. of Utilization (for mail), Washington Gas Light Co.. 411 Tenth St. N.W., Washington, D. C.. and 25 W. Irving St., Chevy Chase, Md. OVERTON, Sidney H. (Af 1929), Repr., Ameri can Radiator Co., 205 Mackay Mansions Rissik St., Johannesburg, S. Africa. P PABST, Charles S. (Af 1934), Pres, and Mgr. (for mail), Adams Engrg. Co., Inc., 55 West 42nd St., New York, and 8727-98th St., Woodhaven, L. J., N. Y. PAETZ, Herbert E. (Af 1922), Div. Sales Mgr. (for mail), American Blower Corp., 2539 Wood ward Ave., and The Wardell, Detroit, Mich. PAGE, Arvin (Af 1935), Asst. Chief Engr. (for mail), The Bahnson Co., 1001 S. Marshall St., and 600 Arbor Road, Winston-Salem, N. C. PAGE, Harry W. (Af 1923), Pres, (for mail), Wisconsin Equipment Co., 918 N. Fourth St., Milwaukee, and 7927 Warren Ave., Wauwatosa, Wis. PALMER, Robert T. (A 1935), Patent Lawyer (for mail). 49 Federal St., Boston, and 8 Glendale Road, Sharon, Mass. PAPPENFUS, Wilfrid G. (S 1935), Production Engr., Collins Radio, 621 First Ave. S.E., and (for mail), 1615 Second Ave. S.E., Cedar Rapids, Iowa. PARK, Clifton D. (Af 1929), 59 Otis St., Need ham, Mass. PARK, J* Frank (J 1930), Sales Engr. (for mail). Carrier Engrg. Corp., 748 E. Washington Blvd., Los Angeles, and Route 3, Box 956, Modesto, Calif. PARKER, Philip (Af 1915), 8 Middle St., Woburn. Mass. PARROTT, Lyle George (Af 1922), Consulting Engr., McCoIl, Snyder & McLean, 2306 Pen obscot Bldg., and (for mail), 4678 Seebaldt Ave., Detroit, Mich. PARSONS, Roger A. (J 1933), City Heat Dept., Board of Water & Electric Light Commissioners, 215 E. Ottawa St., and (for mail), 525 W. Grand River Ave., Lansing. Mich. PARTLAN, James W. {Life Member; Af 1916), 14290 Goddard Ave., Detroit, Mich. PATERSON, James S.* (Af 1922), Mech. Engr. (for mail). Board of Education, 155 College St., and 23 Norton Ave., Toronto, Ont., Canada. PATORNO, Sullivan A. S. (Af 1923), ConsulUng Engr. (for mail). 101 Park Ave., and 312 East 163rd St., New York. N. Y. PAUL, Donald I. (.J 1932), Sales Engr. (for mail), Gurney Foundry Co., Ltd;, 4 Junction Road, and 222 Fern Ave., Toronto, Ont., Canada. ' PAUL, Lawrence O. (J 1935), Engr. (for mail). Carrier Engrg. Corp., Room 907, 180 N. Michi gan Blvd., and 2501 WUcox SL, Chicago, III. PAYNE, Robert E. (Af 1935), Draftsman, E. 1. DuPont de Nemours Co., Wilmington, Del., and (for mail), 244 Sedgewood Road, Springfield, Pa. PEACOCK, James K. (Af 1921), Asst. Secy., Hoffman Specialty Co., 500 Fifth Ave., New ' York, and (for mail), 440 Fowler Ave., Pelham Manor, N. Y. ' PEEBLES, John K., Jr. .(4 1925; J 1924), 7 Brandon Apt., Univereity, Va. FELLER, Leonard (J 1934), Engr., Electrimatic Corp., 2100 Indiana Ave,, and (for mail), 1359 N. Wells St., Chicago, 111. 34 Roll of Membership PELOUZE, Henry L,, 2nd (/t 1934), Branch Mgr. (for mail), C. A. Dunham Co., 110 N. Seventh St., and 4209 Grove Ave., Richmond, Va. FENNEL, Reed (J 1933). 1335 Grand Ave., St. Paul, Minn. PENNOCK. William B. (Af 1927), Sales Engr., Pennock Engrg., 63 Sparks St., and (for mail), 326 Waverly St., Ottawa, Ont., Canada. PLAYFAIR, George Alexander (A 1924), Mgr. (for mail), Johnson Temperature RegulaUng Co. of Canada, Ltd., 97 Jarvis St., Toronto, and West Hill, Ont., Canada. PLEWES, Stanley E. (Af 1917), Philadelphia Mgr. (for mail), Johnson Service Co., 2853 North 12th St., Sta. 8., Philadelphia, and 309 Evergreen Road, Jenkintown, Pa. PERINA, Arthur E. (5 1933), 126 Courtland St.. Port Richmond, S. I., N. Y. PLUM, Leroy H. (Af 1935; A 1934), Industrial Engr., Minneapolis-Honeywell Regulator Co., PERKINS, Robert C. (A 1935), Dist. Repr. (for mail), Ilg Electric Vtg. Co., 230 Sterick Bldg., 2240 N. Broad St., Philadelphia, Pa., and (for mail), 215 Guilford Ave., Collingswood, N. J. and 1888 S. Parkway, Memphis, Tenn. PLUNKETT, John H. (Af 1925), Retired, .81 PESTERF1ELD, Charles H. (S 1932), Box 554. Woodrow Ave., Dorchester, Mass. Univ. Sta., Dept of Mech. Engrg., University of North Dakota, Grand Forks, N. D. PETERS, Herbert H, (Af 1930). Mgr., H. H. Peters Htg. Co., 1842 North 40th St., Mil waukee. Wis. PETERSEN, Stanley E. (J 1935), Estimator and Draftsman for Air Cond., W. A. Ramsay, Ltd-, P. O. Box 1721, Honolulu. Hawaii. POEHNER, Robert E. (Af 1928), Htg. Contr., 849 Massachusetts Ave., Indianapolis, Ind. POGALIES, Louis H. (Af 1931). Mech. Engr., Wilbur Watson & Associates, 4614 Prospect Ave., and (for mail), 4102 Archwood Ave.. Cleveland, Ohio. POHLE, Kenneth F. (A 1930), Vice-Pres., W. F. PETERSON, Sterling D. (A 1930), Branch Mgr. (for mail), Johnson Service Co., 473 Colman Hirschmati Co., Inc., 202 East 44th St., New York, N. Y. Bldg., and 5051 Prince St., Seattle, Wash. POLDERMAN, Lambert H. (Af 1927). Vice- PFEIFER, Otto J., Jr. (A 1935; J 1932), Engr.. Pres. (for mail). Carrier Engrg. Corp. of Cali Ralph D. Thomas & Associates, 1200 Second fornia, 748 E. Washington Blvd., and 3462 Ave. S., and (for mail), 1515 Monroe St., N.E., Minneapolis, Minn. PFUHLER, John L. (A 1925; J 1923). Plbg. and Htg., 600 Manor Road, West New Brighton. Staten Island, N. Y. Lambeth St.. Los Angeles, Calif. POLLARD, Alfred L. (A 1932), Gen. Supt., Steam Heat Dept, (for mail), Puget Sound Power & Light Co., 601 Electric Bldg., and 3009-28th W.. Seattle, Wash. PHILIP, William (Af 1930). 74 Bastedo Ave., Toronto, Ont.. Canada. PONSELL, Francis L (A 1935), Sales Engr.. James P. Ponsell & Sons, 1609 Pennsylvania PHILLIPS, Frederic W., Jr. (Af 1921), L. J. Ave., and (for mail), 2708 Madison St., Wilming Mueller Furnace Co., 101 Park Ave., New York, ton, Del. and (for mail), 825 East 38th St., Brooklyn, N. Y. POPE, S. Austin (Af 1917), Pres, (for mail), PHIPPS, Frederick G. (Af 1930), Vice-Pres., William A. Pope Co., 26 N. Jefferson St., Chicago, Preston Phipps, Inc., 955 St. James St. W., and and 831 Ashland Ave., River Forest, 111. (for mail), 2054 Mercier Ave., Montreal, P. Q., Canada. POSEY, James (Af 1919), Consulting Engr. (for mail), 1755 Baltimore Trust Bldg., and 4005 PIERCE, Edgar D. (J 1933), Air Cond. Engr.. Liberty Heights Ave., BalUmore. Md. Carrier Engrg. Corp., 748 E. Washington, and (for mail), 5738 S. Grammercy Place, Los Angeles, Calif. POTVIN, Leo J. (A 1934), Sales Engr., Hoffman Specialty Co.. Inc., 130 N. Wells St., Chicago, and (for mail), 341 Walnut St., Elmhurst, 111. PIHLMAN, Arthur A. (Af 1928), Service Engr. (for mail), Consolidated Gas Co. of New York, 4 Irving Place, New York, N. Y.t and 98 Sherman Place, Jersey City, N. J. PIKE, Wallace H. (Af 1935), Engrg. De^agner. Ternstedt Mfg. Co., W. Fort St., and (for mail), 5244 Lakeview Ave., Detroit, Mich. PILLEN, Harry A, (A 1933), Mfrs. Repr. (for mail), Harry A. Pillen Co., 622 Broadway, and 2124 Crane Ave., CincinnaU, Ohio. POUCHER, Richard C. (5 1935), 1480 Chelms ford St., St. Paul, Minn. POWELL, Knox A. (J 1935; S 1933), Research Engr., Minneapolis-Moline Power implement Co., 29th and Minnehaha Aves., and (for mail), 1008-18th Ave. S.E., Minneapolis, Minn. POWERS, Edgar C. (A 1934; J 1931), Sales Engr. (for mail). Blue Coal-Corp., 1020 Lewis Tower Bldg.. Philadelphia, Pa., and 309 West mont Ave., Westmont, N. J. PINDER, Percy H. (Af 1919), 366. Third Ave., New York, N. Y. PINES, Sidney (Af 1920), Vice-Pres. (for mail), POWERS, Fred I. (Af 1920), Factory Repr. (for mail). Box 324, and 605 S. Sixth Ave., Bozeman, Mont. Natkin & Co., 2020 Wyandotte St., and 5225 Charlotte St.. Kaosas City, Mo. PISTLER, Willard C. (Af 1934), Mech. Engr. in POWERS, Fred W. (Af 1911), Pres, (for mail). The Powers Regulator Co., 2720 Greenview Ave., and 900 CasUewood Terrace, Chicago, 1U. charge of design, Carl J. Kiefer, Consulting Engr., 918 Schmidt Bldg., and (for mail). Orchard Lane and Crestview Ave., Pleasant Ridge, CincinnaU, Ohio. POWERS, Lowell G. (J 1930), Sales Engr. (for mail). Carrier Engrg. Corp., 1501 Carew Tower, Cincinnati, Ohio, and 738 W. Diamond Ave., Hazleton, Pa. PITCHER. Lester J. (Af 1929; A 1928; J 1924), 8129 Dante Ave., Chicago, 111. PITTOCK, Louis B. (Af 1930), (for mail), 429-B Oliver Bldg., and 80 Berry St., Crafton Station, Pittsburgh, Pa. PRENTICE, Oliver J. (A 1927), Mgr. (for mail), C. A. Dunham Co.. 450 E- Ohio St., and 850 Lake Shore Drive, Chicago, 111. PRESDEE, Cliff W. (A 1926). 228 N. LaSalle SL. ' Chicago, 111. PlWINSKl, Edward J. (S 1935), Learner-Crane Co., 4000 S. Kedzie Ave., and (for mail), 1057 ' N. Leavitt St., Chicago, III. P1ZIE, Stuart G. (A 1926), Vice-Pres. and Gen. Mgr. (for mail). Engineering Sales Co., P. O. Box 53, and 50 S.W. 19th Road. Miami, Fla. PLACE, Clyde R. (Af 1924), Consulting Engr.. (for mail). 420 Lexington Ave., and 333 East 57th St., New York, N. Y. . PLAENERT, Alfred B. (A 1933; J 1927), Resident Engr., Inspector P. W. A., 1102 S. Park St., Madison, Wis. PRICE, Charles E. (A 1933), Treas. (for mail), Keeney Publishing Co., 6 N. Michigan Ave., Chicago, and 1151 Chatfield Road, Winnetka, 111. PRICE, Douglas O. (Af 1934), Htg. and Air Cond. Engr., General Steel Wares, Ltd., 199 River St., and (for mail). 145 Eastbourne Ave., Toronto, Ont., Canada. PRICE, Ernest H. (J 1934; 5 1932), c/o Haff Supply, Inc., Box 328, Riverhead, L. I., N. Y. PRIESTER, Gayle B. (J 1935; 5 1934), Air Cond. Engr., Carrier Engrg. Corp., 408 Chrysler Bldg., New York, N. Y. 35 American Society of Heating and Ventilating Engineers Guide, 1936 PRYIBIL, Paul L. (A 1932). Partner. Hucker- RATHER, Max F. (Af 1919), Mgr., Johnson Pryibil Co., 1700 Walnut St., and (for mail), 328 E. Philellena St., Philadelphia, Pa. Service Co., 2142 East 19th St., Cleveland, Ohio. RAUH, Edward M. (5 1934), (for mail). 205 E. PRYOR, Frederick L. (Af 1913), 5 Colt St., Boyd, Norman, and Alva, Okla. Paterson, N. J. PULLEN, Royal R. (Af 1935; A 1935), Mech. RAY, Lewis B. (Af 1932), Pres, (for mail), Ray Engineering Co., Inc., 800 Broad St., Newark, Engr., 109 Hill St., Lead, S. D. PUNG, Donald W. (5 1935), Sales Engr., Insulite Co., 1100 Builders Exchange, and (for mail), 315-19th Ave. S.E., Minneapolis, Minn. and 151 Augusta St., Irvington, N. J. RAYMER, William F,, Jr. (7 1934), Sales Engr. (for mail), American Blower Corp., 249 High St., Newark, and 50 N. Munn Ave., East Orange, PURCELL, Frederick C. (Af 1926), Dist. Mgr. (for mail). National Regulator Co., 2847 Grand River Ave., and 201 E. Kirby Ave., Detroit, Mich. N. J. RAYMOND, Fred I.* (A 1929), Pres, (for mail), F. I. Raymond Co., 629 W. Washington Blvd., Chicago, and 547 N. Keystone Ave., River PURCELL, Robert E, (Af 1916), 4061 Seebaldt Ave., Detroit, Mich. PURDY, A. K. (Af 1922), Pres, (for mail), Purdy, Mansell, Ltd., 63 Albert St., and 30 Glenrose Forest, 111. RAYNIS, Theodore (7 1934). Draftsman (for mail). Central Drafting Office, New York Navy Yard, and 8705-89th Ave., Woodhaven, L. I,, Ave., Toronto, Ont., Canada. . PURDY, Randall B. (A 1927), Assoc. Editor, Power (for mail), McGraw-Hill Publishing Co., N. Y. ,, READ, Robert R. (5 1934), (for mail). 1641 East 117th St., Cleveland, and 2722 Owaisa Road, 330 West 42nd St., New York, and 224-05-139th Ave., Laurelton, L. I., N. Y. PURINTON, Dexter J. (A 1923), Associate (for Cuyahoga Falls, Ohio. _ RECK, William E. (Af 1927), Civil Engr. (for mail). The Reck Heating Co., Ltd., Esromgade mail), Voorhees, Gmelin & Walker, Archts., 101 15, Copenhagen N., and Sundvej 16, Hellerup, Park Ave., New York, N. Y., and 23 Sachem Road, Greenwich, Conn. PURSELL, H. E. (Af 1919), Special Repr., Kewanee Boiler Corp., Kewanee, III. Denmark. , REDSTONE, Arthur L. (Af 1931), Research Engr. (for mail), Proctor & Schwartz, Seventh and Tabor Road, and Park Towers, Kemble and PYLE, John W. (Af 1919), Peru Htg. Co., and (for mail), 371 W. Third St., Peru, Ind. Ogontz Ave., Philadelphia, Pa. REED, Irving G. (7 1934). Asst. Supt. and Chief Engr. (for mail). Room 417, Grant Bldg., Inc., o 310 Grant St., and 3227 Middletown Road, Sheridan Sta., Pittsburgh, Pa. . QUAY, D. M.* (Charter Member; Life Member; REED, Paul L. (A 1932), 1034 Art Hill Place, Presidential Member), (Pres., 1900; 1st VicePres., 1896-1899; 2nd Vice-Pres., 1895), 725 Eastern Ave., Beliefontaine, Ohio. QUEER, Elmer Roy (Af 1933), Research Engr. (for mail). The Pennsylvania State College Engrg. Experiment Station, and Arbor Way, State College, Pa. QUIGLEY, William J. (Af 1920), 27 Knowlton Ave., Kenmore, N. Y. QUIRK, Clinton H. (Af 1916; 7 1915), Repr. (for St. Louis, Mo. _ #,, REED, Van A., Jr, (Af 1930), Mech. Engr. (for mail), Federal Engrg. Co., 239 Fourth Ave.. Pittsburgh, and 114 Water St., Elizabeth, Pa. REED, William M. (Af 1927), American Air Filter Co., 215 Central Ave., Louisville, Ky. REGER, Henry P. (Af 1934), Pres, and Treas. (for mail), H. P. Reger & Co., 1501 East 72nd Place, and 6939 Bennett Ave., Chicago, 111. REID, Henry P. (Af l931; A 1927), Special Engr. mail), Trane Co., 250 East 43rd St., New York, and 465 Front St., Hempstead, L. I., N. Y. (for mail), Universal Atlas Cement Co., 208 S. LaSalle St., Chicago, and 3507 Oak Park Ave., Berwyn, 111. ,,. ,, R REID. Herbert F. (A 1932), Reid-Graff Plbg. Co., 1417 Peck St., Muskegon Heights, Mich. RACHAL, John M. (J 1930), Mgr., Air Cond. Dept, (for mail), Carrier-Brunswick Inter REIK, Robert C. (7 1935). Engr., L. E. Stevens Co,. 622 Broadway, Cincinnati, Ohio, and (for national, Inc., 850 Frelinghuysen Ave., Newark, mail), 37 W. Southgate, Ft. Thomas, Ky. and 61 S. Munn Ave., East Orange, N. J. REILLY, Charles E. (7 1928), 4920 City Line RACK, Edgar C. (Af 1931), Consulting Engr., Ave., Philadelphia, Pa. ,,,, Johns Manville Corp., 22 East 40th St., New REILLY, J. Harry (Af 1931; A 1931; 7 1929). York, N. Y.t and (for mail), 288 Park Ave., Sales Engr., American Radiator Co., 402 Broad East Orange, N. J. St., Newark, and (for mail), 14 Watson Ave., RA1NE, John J. (Af 1912), Vice-Pres. (for mail). East Orange, N. J. '. The G. S. Blodgett Co.. 190 Bank St., Burling REINKE, Alfred G. (7 1933), Group Leader on ton, and Essex Junction, Vt. Instruments, Westinghouse Electric & Mfg. Co., RAINGER, Wallace F. (A 1930; 7 1924), 441 95 Orange St., Newark, and (for mail), 319 Park Hawthorne Ave., Yonkers, N. Y. . Place, Irvington, N. J. . . RAISLER, Robert K. (A 1933; 7 1930), Treas. (for . RENOUF, E. Prince (Af 1933), Mgr., Air Cond. mail), Raisler Heating Co., 129 Amsterdam Ave., Dept' (for mail), Straus Frank Co., and 2815 . and 25 East 77th St., New York, N. Y. RANCK, Guy L. (A 1933), Mgr., C. A. Dunham Co.. 3605 Laclede Ave., St. Louis, and (for mail), Truxillo Ave., Houston, Texas.. RENTE, Harry W. (Af 1931), Htg. Engr., Oil Burners, 70 W. Chippewa St., and (for mail), 472 Pasadena Ave., Webster Groves, Mo. 114 Morris Ave., Buffalo, N. Y. RANDALL, W. Clifton* (Af 1928), Chirf Engr. RENTE, Sidney R. (A 1930), R-O Distributors. (for mail), Detroit Steel Products Co., 2250 E. Inc., 775 Main St., Buffalo, and (for mail), 31 Grand Blvd., and 5540 Ridgewood Ave., Detroit, Mich. Garrison Road, WiUiamsville, N. Y. REPKO, Joseph J, (5 1934), 4924 Hamm Ave., RANDOLPH, Charles H. (Af 1930; A 1928; Cleveland. Ohio. .... 7 1926), Air Cond. Engr., The Milwaukee . RETTEW, Harvey F. (Af 1929), Htg. and Vtg. Electric Railway & Light Co., 217 W. Michigan Engr., Board of Education, 21st and Winter, and St., and (for mail), 1925 N. Prospect Ave., (for mail), 6821 Martins Mill Road, Philadelphia, Milwaukee, Wis. RANSOM, Clifford F. (5 1935), 313 E. Spring- * REYNOLDS, Thurlow W. (Af 1922), Consulting field. Champaign, 111. Engr., 100 Pinecrest Drive, Hastings-on-Hudson, RASMUSSEN, Robert P. (Af 1931), Pres, (for N. Y. mail). Economy Equipment Co., 538 W. Pershing REYNOLDS, Walter V. (A 1928), Pres., Walter Road, and 1243 East 46th St., Chicago, 111. RATHBUN, Perry W. (Af 1933), Resident Engr., Reynolds, Inc., 861 Third Ave.. New York, N. Y. RHEA, Chester A. (A 1931), Steel Boiler Repr., Inspector P. W. A., and (for mail), 1809 North National Radiator Corp., and (for mail), 722 west 37th St., Oklahoma City, Okla. Carpenter Lane, Philadelphia, Pa. 36 Roll op Membership RICE, C. J. (A 1923), Pres, (for mail). Sterling Engrg. Co., 3738 N. Holton St., and 3376 N. Summit Ave., Milwaukee, Wis. RICE, Robert B. (Af 1934), Assoc. Prof, in Mech. Engrg. (for mail), Newark College of Engineering, 367 High St., Newark, and 165 Rutgers Place, Nutley, N.jf. RICHARD, Edwin J. (Af 1933), Owner (for mail), Edwin J. Richard Equipment Co., 528 Chamber of Commerce Bldg., and 3564 Paxton Ave., Cincinnati, Ohio. RICHARDSON, Henry G. (Af 1934), Vice-Pres., Hawley Richardson Williams Co., 204 Dooly Bldg., and (for mail), 1433 Harvard Ave., Salt Lake City, Utah. RICHARDSON, Henry Thomas (A 1930), Vice-Pres. (for mail), Richardson & Boynton Co., 244 Madison Ave., and 156 East 79th St., New York, N. Y. RICHMOND, John (S 1933), 5285 Forbes St., Pittsburgh, Pa., and (for mail), 951 Helmsdale Road, Cleveland Heights, Ohio. RICHTMANN, William M.* (A 1932; 7 1926), Asst. Prof, of Engrg. (for mail), Texas College of Arts and Industries, and 709 W. Santa Gertrudes St., Kingsville, Texas. RICKNER, Charles A. (Af 1935), Air Cond. Engr., Kelvinator Corp., 14250 Plymouth Road, and (for mail), 15895 Gilchrist, Detroit, Mich. RIES, Lester S. (Af 1929), Asst. Supt., Bldgs, and Grounds (for mail). University of Chicago, 960 .East 58th St., and 5614 Blackstone Ave., Chicago, 111 RIESMEYER, Edward H., Jr. (7 1930), Htg. Engr., Schaffer Htg. Co., 231-33 Water St., and (for mail), 4702 Stanton Ave., Pittsburgh, Pa. RIETZ, Elmer W.* (Af 1923), Gen. Sales Mgr. (for mail). Powers Regulator Co., 2720 Greenview Ave., Chicago, and 940 Greenwood Ave., Winnetka.'Ill. RILEY, Champlain L. (Af 1906), (.Presidential Member), (Pres., 1921; 1st Vice-Pres., 1920; Council, 1918-1922), Clark-MacMullen & Riley, Inc., 10l Park Ave., New York, N. Y. RILEY, Edward C. (7 1935; 5 1933), Mass. Div. of Occupational Hygiene, Dept, of Labor and Industries, 23 Joy St., Boston, and '(for mail), 51 Centre St., Brookline, Mass. RILEY, Robert C. (S 1934), 8S-37-179th St., Jamaica, N. Y. RINEHART, Wilson R. (7 1932), Choudrant, La. RITCHIE, A. Gordon (Af 1933), Pres, and Mgr. (for mail), John Ritchie, Ltd., 102 Adelaide St. E., and 41 Garfield Ave., Toronto, Ont., Canada. RITCHIE, Edmund J. (Af 1923), Vice-Pres. (for mail), Sarco Co., Inc., 183 Madison Ave., New York, and 2 Grace Court, Brooklyn, N. Y. RITCHIE, William' (Af 1909), 17 Van Reipen Ave., Jersey City, N. J. RITTER, Arthur.(Af 1911), New York Dist. Mgr. (for mail), American Blower Corp., 401 Broad way. New York, and 29 Edgemont Road, Scarsdale, N. Y. RIVARD, Melvin M. (Af 1935), Mgr., Rivard Sales Co., 1805 West 49th St. Terrace, Kansas ` City, Mo.. - ROBERTS, Henry L. (Af 1916), Engr. and Con tractor (for mail), 228 North 16th St., Phila delphia, and 1014 Allston Road, Brookline, Delaware Co., Pa. mail), Sutherland Air Cond. Corp., 627 Mar quette Ave., and 2423 Portland Ave., Minne apolis, Minn. ROBINSON, George L. (A 1935), Draftsman and Designer, E. I. DuPont de Nemours Co., Wil mington, Del., and (for mail), 1523 Carlisle Ave., Prospect Park, P^. ROBINSON, Harry C. (Af 1930), Htg. Engr., 676 Pleasant St., Worcester, Mass. ROCKWELL, Theodore F. (Af 1933; A 1933; 1932) Instructor (for mail), Carnegie Institute f Technology, and 131 Edgewood Ave., Pitts burgh, Pa. RODENHEISER, George B. (Af 1933), Head- Htg. and Vtg. Dept, (tor mail), David Ranken, Jr., School of Mech. Trades, 4431 Finney Ave., and 3639 A, Dover Place, St. Louis, Mo. RODGERS, Frederick A. (A 1934), Branch Mgr., Minneapolis-Honeywell Regulator Co/, 4500 Euclid Ave., Cleveland, and (for mail), 2577 Ashton Road, Cleveland Heights, Ohio. RODGERS, Joseph S. (7 1934), Sales Engr., Hajoca Corp., Baltimore, and (for mail), 1 Third Ave., Brooklyn Park, Md. RODGERS, William C. (S 1935), 400 Morewood Ave., Pittsburgh, Pa. RODMAN, Robert W. (Af 1922), Supt. of Plant Operation (for mail). Board of Education, City of New York, 500 Park Ave., and 175 West 73rd St., New York, N. Y. ROEBUCK, William, Jr. (Af 1917), Mfrs. Repr. (for mail), 311 Jackson Bldg., and 154 Sanders Road, Buffalo, N. Y. ROHLIN, Karl W. (Af 1930), Engr. (for mail), Warren Webster & Co., 17th and Federal Sts., Camden, and 4453 Terrace Ave., Merchantviile, N. J. ,, ROLLAND, S. L. (A 1934), Design Engr. (for mail), Oklahoma Gas & Electric Co., 321 N. , Harvey Ave., and 2131 Northwest 20th St., Oklahoma City, Okla. ROOS, Erik B. J. (7 1935), Engr., Carrier Engrg. Corp., 850 Frelinghuysen Ave., Newark, and (for mail), 405 N. Union Ave., Cranford, N. J. ROSE, Arnold A. (A 1935), Sales Engr., Fitz- gibbons Boiler Co., 185 Main St., and (for mail), ' Briarview Manor Apt., White Plains, N. Y. ROSE, Howard J. (Af 1934), Sales Engr., Fitz- gibbons Boiler Co., Inc., 185 Main St., White Plains, and (for mail), 100 Siebrecht Place, New Rochelle, N. Y. ROSEBROUGH, Robert M. (Af 1920), Branch Mgr. (for mail), L. J. Mueller Furance Co., 4246 Forest Park Blvd., St. Louis, and 16 E. Cedar Ave., Webster Groves, Mo. ROSELL, Axel F. (Af 1935), Mech. Engr., A. B. Svenska Flaktfabriken Kungsgatan 8, Stockholm, and (for mail), Kv Atlas 3, Lidingo l, Sweden. ROSENBERG, Philip (A 1928), Secy-Treas,, Universal Fixture Corp., 137 West 23rd St., and (for mail), 250 West 104th St., New York, N. Y. ROSENBURG, William E. (7 1935), PIbg-Htg., John C. Rosenburg, Birch Hill Road., Locust Valley. L. I.. N. Y. ROSS, John O.* (Af 1920), Ross Industries Corp., 350 Madison Ave., New York, N. Y. ROSSITER, Paul A. (5 1935), 88 Kent St., Minneapolis, Minn. ROTH, Charles F. (A 1930), Mgr., International Htg. & Vtg. Exposition, Grand Central Palace, New York, and (for mail), 141 East 36th St., New York (Nov. 1 to April 30), and Dreamthorp, Bedford Village, N. Y. (May 1 to Oct. 31). ROTH, Harold R. (Af 1935), Mgr. (for mail), Canadian Sirocco Co., Ltd., Room 321, 57 Bloor St. W., and 18 Tichester Road, Toronto, Ont., Canada. . ROTTMAYER, Samuel I. (A 1933; 7 1928), Mech. Engr., Libby, McNeill & Libby, U. S. Yards, and (for mail), 7861-B South Shore Drive, Chicago, 111. . ROWE, William A. (Af 1921), (Council, 1929 1931), Mech. Engr., 718 Longfellow Ave., Detroit, Mich. ROWLEY, Frank B.* (Af 1918), (Presidential Member), (Pres., 1932; 1st Vice-Pres., 1931:2nd - Vice-Pres, 1930; Council, 1927-1933), Prof, of ' Mech. Engrg. and Director of Experimental Engrg. Lab., University of Minnesota, and (for mail), 4801 E. Lake Harriet Blvd., Minneapolis, * Minn. ROYER, Earl B. (Af 1928), Designing Engr., Fosdick & Hilmer, 1703 Union Trust Bldg., and (for mail), 0635 Iris Ave., Cincinnati, Ohio. . RUDIO, H. M. (Af 1921), Mgr., Air Cond. Dept. , (for mail), Gustin Bacon Mfg. Co., 1412 West 12th St., and 6639 Edgerale Road,.Kansas City, Mo. 37 American Society of Heating and Ventilating Engineers Guide, 1936 RUEGER, Charles A., Jr. (A 1935), Salesman (for mail), American Radiator Co., P. O. Box 505, Winston-Salem, N. C., and 2805 Floyd Ave., Richmond. Va. - RUFF, Adolph G. (Af 1935), Plant Engr., U. S. Playing Card Co., Norwood, and (for mail), Box 355 R. F. D. 5, Lockland, Ohio. RUFF, DeWItt C. (Af 1922), Healy-Ruff Co., 765 Hampden Ave., St. Paul, Minn. RUGART. Karl (A 1924), Dist. Mgr. (for mail). Warren Webster & Co., 26 South 20th St., and 5830 Willows Ave., Philadelphia, Pa. RUNKEL, Charles (M 1935), Pres, (for mail). Acme Htg. & Vtg. Co., Inc., 4224 S. Lowe Ave., and 7921 S. Hermitage Ave., Chicago, 111. RUPPERT, Edward H. (A 1923), 85 Eastern Pkwy., Brooklyn, N. Y. RUSSELL, J. Nelson (if 1899), Managing Dir. (for mail), Rosser & Russell, Ltd., Romney House Marsham St., Westminster, and Fernacres Fulmer near Slough, Buckinghamshire, England. RUSSELL, W. A. (Af 1921), (Council, 1934-1935), Mgr., K. C. Branch (for mail), U. S. Radiator Corp., 1405 West 11th St., and 239 Ward Pkwy., Kansas City, Mo. RUSSELL, William B. (Af 1928), Colorado Ave.. R. F. D. 1, Joliet, 111. RYAN, Harry J. (Af 1922). 47 Harris Ave., Albany, N. Y. RYAN, James D. (Af 1935), Bldg. Mgr. and Engr., Whitney National Bank, St. Charles and Gravier St., and (for mail), 215 N. Rendon St., New Orleans. La. RYAN. William F. (J 1933), Sales Engr.. The Lee Hardware Co., 250-252 N. Santa Fe, and (for mail), 134 S. Columbia, Salina, Kan. RYDELL, Carl A. (Af 1931; A 1931; 7 1928), Owner, C. A. Rydell Associates (for mail). 168 Dartmouth St., Boston, and 286 Quinobequin Road, Waban, Mass. s SABIN, Edward R. (Af 1919), Pres., Edward R. Sabin Co., 4710-12 Market St., Philadelphia, Pa. SADLER, C. Boone (M 1928), Assoc. Civil Engr., (for mail). Public Works Office, 11th Naval District, and 4826 Voltaire St., San Diego, Calif, ' SAITO, Shozo (Af 1923), Marunouchi Bldg., Opposite Tokyo Sta., Tokyo, Japan. SAKOUTA, Mathleu L. (M 1924), Consulting Engr. and Expert, Gavan, Simanskaia 4-A, Leningrad, U. S. S. R. . SANBERN, E. Nute* (Af 1923), Engr. (for mail), Hoffman Specialty Co., Inc., 500 Fifth Ave., New York, N. Y- and 123 S. Haviland Ave., . Audubon, N. J. SANDS. Clive C. (Af 1929), G. P. O. Box 601 F. F., Sydney N. S. W., Australia. SANFORD, Arthur L. (Af 1915), Mech. Engr., 4240 Aldrich Ave. S., Minneapolis, Minn. SANFORD, Sterling S.* (Af 1930), Sales Engr. (for mail), Detroit Edison Co., 2000 Second Ave., and 1503 Seyburn Ave., Detroit, Mich. SANTEE, Helen C. (Af 1930), Asst, to Architect and Engr., City School Dist., 81 N. Washington St., and (for mail), 900 S. Franklin St., Wilkes- Barre, Pa. SAUER, Robert L. (A 1930), Dist. Sales Mgr. (for mail), Riley Stoker Corp.. Ft. of Walker St., and 3315 W. Philadelphia, Detroit, Mich. SAUNDERS, Laurence P. (Af 1933). Director of Engrg-, Harrison Radiator Corp., Lockport, N. Y. SAWDON, Will M. (Af 1920), Prof. Experimental Engrg. (for mail), Cornell University, and 1018 E. State St., Ithaca, N. Y. SAWHILL, R. V. (A 1929), Executive Vice-Pres. (for mail). Domestic Engineering, 110 East 42nd St- New York, and 115 Townsend Ave., Pelham Manor, N. Y. SAWYER, J. Neal (/ 1933), Sales Engr. (for mail). Air Conditioning Engrg. Corp., 440 Ward Pkwy., and 4229 Oak St., Kansas City, Mo. SCANLON, Edward S. (A 1934), 2516 Homehurst Ave., Pittsburgh, Pa, SCHECHTER, John P. (7 1935), Engr., Domestic Air Cond. Co., 171 Victor, and (for mail), 1812 Bums Ave., Detroit, Mich. SCHE1DECKER, Daniel B. (A 1919), Secy, (for mail), Hunter-Clark Vtg. System Co., 2800 Cottage Grove Ave., and 4626 N. Kilboum Ave., Chicago. 111. ' SCHERNBECK, Fred H. (A 1930). Salesman (for mail), Williams Bros. Boiler & Mfg. Co., Nicollet Island, and 5045 Portland Ave., Minneapolis, Minn. SCHICK, Karl W. (A 1934). Dist. Mgr., Minne apolis-Honeywell Regulator Co., 561 Reading Road, and (for mail), 2300 Auburn Ave., Cincin nati, Ohio. SCHLICHTING, Walter G. (Af 1932). Mgr., Air Cond. Dept., Clarage Fan Col, and (for mail), 1417 W. Lovell St., Kalamazoo, Mich. SCHMIDT, Richard H. (5 1934), 2139 Abington Road, Cleveland, Ohio. SCHMUTZ, Jean (Af 1933), Admistrateur-Delegue Societe PRSM 8 Passage de I'Atlas, and (for mail), 18 Rue Dufrenoy, Paris 16, France. SCHNErDER, William G. (Af 1932), (for mail). The American Brass Co., 25 Broadway, New York, and 45 Wayne Ave., White Plains, N. Y. SCHNITZER, Sidney (5 1935), Development Engr., Taylor Manufacturing Corp., 2330 Claybourn Ave., and (for mail), 2031 W. Wisconsin Ave., Milwaukee, Wis. SCHOENIJAHN, Robert P. (Af 1919), Consulting Engr. (for mail), 304-5 Industrial Trust Bldg., and 719 Nottingham Road, Wilmington, Del. SCHOEPFLIN, Paul H. (Af 1920), Pres, (for mail), Niagara Blower Co., 6 East 45th St., New York, and 91 Valley Road, Larchmont, N. Y. SCHUCANY, Oscar W. (5 1935), Lockart, Texas. SCHULZ, Howard I. (A 1915), Crane Co., 1223 W. Broad St., Richmond, Va. SCHULZE, Benedict H. (Af 1921), Sales Mgr. (for mail), Kewanee Boiler Corp., 37 West 39th St., and 67 Park Ave., New York, N. Y. SCHURMAN, John A., Jr. (/ 1935), Asst. Branch Engr. in charge of Air Cond. (for mail), York Ice Machinery Corp., Ohio Branch, 2700 Washington Ave. N.W., Cleveland, and 1029 Parkside Drive, Lakewood, Ohio. SCHWANTES, Arno R. (7 1935). Sales Engr.. Waterman-Waterbury Co., 106 S. University Ave., Beaver Dam, Wis. SCHWARTZ, Jacob (7 1929), Htg. Contr. (for mail), Samuel Schwartz & Son, Inc., 30 West 27th St.. Bayonne, and 12 Van Houten Ave., Jersey City. N. J. SCHWEIM, Henry J. (Af 1928). Chief Engr. and Secy, (for mail). Gypsum Association, 211 W. Wacker Drive, and 7633 Bosworth Ave., Chicago, SCOFIELD, Paul C. (7 1933). Engr. (for mail). Carrier Engrg. Corp., 748 E. Washington Blvd., and 830 N. Occidental Blvd., Los Angeles, Calif. SCOTT, Charles E. (Af 1907). Pres, and Treas. (for mail). Vapor Engrg. Co., 489 Fifth Ave., New York, N. Y., and Darien, Conn. SCOTT, George M. (Af 1915), Vice-Pres. (for mail). Child & Scott-Donohue, Inc., 112 Wooster St., New York, and 66 - Bowman Ave., Port Chester, N. Y. SCRIBNER, Eugene D. (A 1933; 7 1929), Engr., Mahlstedt Materials, Inc., New Rochelle, N. Y., and (for mail), 261 Clark St., Westfield, N. J. SCUDDER, Barrett (A 1935), Vice-Pres., Jas. P. Marsh Co., 2073 Southport Ave., Chicago, and (for mail), Washington Road, Lake Forest, 111. SEEBER, Rex R. (Af 1934), Head. Mech. Engrg. Dept., Michigan College of Mining & Tech nology, Houghton, Mich. SEELBACH, Herman (Af 1931), Pres, (for mail). Equipment Sales, Inc., 610 Erie County Bank Bldg., Buffalo, and 31 Central Ave., Hamburg, N. Y. SEELERT, Edward H. (A 1935), Secy-Treas. (for mail), McQuay, Inc., 1600 N.E. Broadway, and 2927 Ulysses Ave. N.E., Minneapolis, Minn. 38 Roll of Membership SEELEY, Lauren E.* (Af 1930), Asst. Prof. Mech. Engrg. (for mail). Mason Laboratory, Yale University, and 130 Event St., New Haven, Conn. SEELIG, Alfred E. (Af 1926). Pres, and Gen. Mgr., L. J. Wing Mfg. Co., 154 West 14tb St., and (for mail), 310 Convent Ave., New York, N. Y. SEELIG, Lester (Af 1925), Mech. Engr., Museum of Science and Industry, Jackson Park, and (for SHELDON, William D., Jr. (71934), Chief EngrSheldons, Ltd- and (for mail). Cedar St- Galt, Ont- Canada. SHELNEY, Thomas (Af 1931). Pres, (for mail). Pierce Blower Corp., 100 Rhode Island StBuffalo, and Grand Island, N. Y. SHENK, Donald Hugh (Af 1934), 106 Forest Lane, and (for mail), Riggs Hall, Clemson College, S. C. mail), 725 Irving Park Blvd., Chicago, 111. SEELY, Irving R. (S 1935). General Electric Co., and (for mail), 1059 Wendell Ave., Schenectady, N. Y. SEEPE, Paul E. (A 1933), 2829 Park Ave., Minneapolis, Minn. SEITER, J. Earl* (Af 1928), Asst. Mgr., New Business Dept., Consolidated Gas Electric Light & Power Co., and (for mail), 7117 Bristol Road, Baltimore, Md. SEKIDO, Kunisuke (Af 1903), Consulting Engr., Marunouchi Bldg., No. 855, and (for mail), 19 Momozono Nakano, Tokyo, Japan. SELLMAN, NilsT. (Af 1922), Asst. Vice-Pres. and Asst. Secy, (for mail). Consolidated Gas Co. of New York, 4 Irving Place, New York, and 56 Waldworth Ave- Scarsdale, N. Y. * SENIOR, Richard L. (Af 1925), R. L. Senior. Inc., 103 Park Ave., New York, N. Y. SENNET, Lowell E. (5 1934), Engr., Central Bureau for Htg.' and Air Cond., 309 Euclid, 30th Bldg., Cleveland, and (for mail), 14505 Orinoco, East Cleveland, Ohio. . SEVERNS, William H * (Af 1933), Prof, of Mech. Engrg. (for mail). Dept, of Mech. Engrg., Uni versity of Illinois, and 609 Indiana Ave., Urbana, 111. SHEPARD, Edward C. (Af 1932), Mech. Engr.. Penberthy Injector Co- Detroit, Mich- and (for mail), 2294 University Ave- New York, N. Y. SHEPARD, John deB. (7 1929), Air Cond. ReprConsolidated Gas Electric Light & Power Co Room 406, Lexington Bldg- Baltimore, Md. SHEPPARD, Frank A. (Af 1918), Salesman (for mail), Johnson Service Co- 1031 Wyandotte St and 27 East 70th St- Kansas City, Mo. SHEPPARD, William G. F. (Af 1922). Partner (for mail), Sheppard & Abbott, 119 Harbord St and 1 Clarendon Ave- Toronto, Ont- Canada. SHERET, Andrew (Af 1929; A 1925), Pres, (for mail), Andrew Sheret, Ltd- 1114 Blanshard St and 1030 St. Charles St-, Victoria, B. C- Canada. SHERMAN, Ralph A. (Af 1933), Fuel Engr. (for mail), Battelle Memorial Institute, 505 King Ave- and 1893 Coventry Road, Columbus, Ohio. SHERMAN, Victor L. (Af 1935), Assoc. Prof- Mech. Engrg- College of Engineering, Lewis Institute, Madison and Damen Ave- Chicago, and (for mail), 643 Hillside Ave- Glen Ellyn, 111. SHIVERS, Paul F. (Af 1930), Minneapolis-Honey well Regulator Co- W Canal St- Wabash, Ind. SHODRON, John G. (Af 1921), Consulting Engr. and Research, 419 E. Milwaukee Ave., Ft. Atkinson, Wis. Member), Research Engr., 369 Washington Ave., Brooklyn, N. Y. SHAER, 1. Ernest (A 1934), Sales Engr., B. F. Sturtevant Co., 89 Broad St- Boston, and (for mail), 35 Fessenden St- Dorchester, Mass. SHANKLIN, Arthur P. (Af 1929), Sales Engr. (for mail), Carrier Engrg. Corp., 12 South 12th St., Philadelphia, and 40 Amherst Ave., Swarthmore. Pa. SHANKLIN, John A. (Af 1928), Secy-Treas. (for mail). West Virginia Htg. & Plbg. Co., 233 Hale St- and 1507 Quarrier St- Charleston, W. Va. SHARP, Floyd H. (Af 1929), 117 E. Third St., Jamestown, N. Y. * SHARP, Henry C. (Af 1935), Mgr.. Oil Htg. Div_ (for mail). Smith Oil & Refining Co., and 1928 Rockton Ave., Rockford, 111. SHAVER, Herbert H. (A 1929). Asst. Gen. Sales Agt. (for mail), Hudson Coal Co., 424 Wyoming Ave- and 150>7 Wyoming Ave., Scranton, Pa. SHAW, Burton E. (7 1934), Research Chief, Penn Electric Switch Co- Des Moines, and (for mail), 505 Rapids, Adel, Iowa. SHAW, Edgar (Af 1923), Pres, (for mail), Lynch ' & Woodward, Inc., 320 Dover St., Boston^ and 51 Royal St., Wollaston, Mass. SHAW, Harold W. (5 1935). Engr., Carbide & Carbon Chemicals Corp., South Charleston, and (for mail). Box 940 Charleston, W. Va. SHAW, Norman J. H. (Af 1927; 7 1925), 37 Benjamin Road, Arlington, Mass. SHAWLIN, Walter C. (A 1931), Mgr. (for mail), Northwestern Ventilation Co., 2540 W. Wells St- and 696 S. Oak Park Court, Milwaukee, Wis. SHEA, Michael B. (Af 1921), Sales Dept, (for mail). American Radiator Co- 1344 Broadway, Detroit, and 104 Massachusetts Ave- Highland SHORB, Will A. (Af 1909), Treas., The Field & Shorb Co., 705 N. Pine St- and (for mail), 3 Lincoln Place, Decatur, III. SHOTWELL, Roger W. (Af 1935), Designing Engr., W. J. Spoelstra Co., Inc- 154 Parker Ave- Hawthorne, and (for mail), 97 Franklin StVerona, N. J. SHROCK, John H. (Af 1924), Mgr. (for mail), New York Blower Co- Factory St- and 1524 Michigan Ave- La Porte, Ind. SHULTZ, Earle (A 1919), Vice-Pres. (for mail), Illinois Maintenance Co- 1136-72 W. Adams St and Edgewater Beach Apts- Chicago, III. SIEBS, Claude T. (A 1927), Service Systems Engr. (for mail), Western Electric Co- Inc- 195 Broadway. New York, N. Y- and Russell Road, Fanwood. N. J. SIEGEL, Leo (Af 1928; A 1925: 7 1924), Company Commander V-CCC Co- 226 Middletown, and (for mail), 1016 Lancaster Ave- Brooklyn, N. Y. SIGMUND, Ralph W. (Af 1932), Dist. Mgr. (for mail), B. F. Sturtevant Co- 913 Provident Bank Bldg- and 304 Oak St- Cincinnati, Ohio. SIMKIN, Milton (S 1933), 103 Brighton Ave Perth Amboy, N. J. ' SIMONDS, Abe H. (A 1935; 7 1929). Sales Engr. (for mail). Carrier Engrg. Corp. of California, 748 E. Washington Blvd- and 446 Westminster Ave- Los Angeles, Calif. SIMPSON, Arthur M. (A 1935), Gen. Sales Mgr. (for mail). Van Kennel Revolving Door Co- 101 Park Ave., New York, and 3430-Slst StJackson Heights, L. I- N. Y. SIMPSON, Donald C. (Af 1932), Mgr- Product Analysis Dept- Industrial Materials Div. (for mail), Owens Illinois Glass Co- and 47 Day AveNewark, Ohio. Park, Mich. . SIMPSON, William K. (Af 1919), Vice-Pres. (for SHEARS, Matthew W. (Af 1922), Htg. EngrC. A. Dunham Co- Ltd- 1523 Davenport Road, mail), Hoffman Specialty Co- and 9 Sands StWaterbury, Conn. and (for mail), 39 Sylvan Ave., Toronto, Ont- SKIDMORE, John G. (7 1930), Air Cond. Engr- Canada. .- Carrier Engrg. Corp- 408 Chrysler Bldg- New SHEFFLER, Morris (Af 1921), Pres, (for mail), York, and (for mail), 510l~39th Ave- Long Sheffier-Gross Co- 203 Drexel Bldg- and 5451 Island City, N. Y. Lebanon Ave- Philadelphia, Pa. SHELDON, Nelson E. (M 1927), Dist. Sales Mgr. (for mail). Carrier Engrg. Corp- 620 Reynolds SKINNER, Henry W. (Af 1920), Consulting Engr., Box 1334, and (for mail),'4816 Dexter StFort Worth, Texas. Arcade Bldg., and 41 Lanark Crescent, Rochester, N. Y. SKLENARIK, Louis (7 1928), 305 East 72nd StNew York, N. Y. 39 American Society of Heating, and Ventilating Engineers Guide, 1936 SLAYTER, Games (Af 1931), Asst. Gen. Mgr., Industrial Materials Div., Owens Illinois Glass Co., and (for mail). Box 726, Newark, Ohio. SLIGHT, Irvin (A 1925), Partner (for mail), Slight Bros., 741 Yorkway Place, Jenkintown, and Hartsville, Pa. SLUSS, Alfred H. (Af 1935), Prof.. Mech. and Industrial Engrg., University of Kansas, and (for mail), 827 Mississippi Ave., Lawrence, Kan. SMAK, Julius R, (A 1934), Supt. of Service Dept., Crane Co.. South Ave., and (for mail), .3135 Park Ave., Bridgeport, Conn. SMALL, Bartlett R. (7 1932), Sales Engr. (for mail), T. C. Heyward, 1408 Independence Bldg., and 326 W. Tenth St., Charlotte, N. C. SMALLMAN, Edwin W. (Af 1920), 833 Allison St. N.W., Washington. D. C. SMITH, Elmer G* (Af 1929). Asst. Prof, of Physics, Agricultural and Mechanical College of Texas, College Station, Texas. SMITH, Gard W. (Af 1927), Salesman, Premier SOPER, Horace A. (Af 1916), Vice-Pres. (for mail). American Foundry & Furnace Co., and 1122 E. Monroe St., Bloomington, 111. SOULE, Lawrence C.* (Af 1908), Secy, and Chief Engr. (for mail), Aerofin Corp., 850 Frelinghuysen Ave., Newark, and Essex Fells, N. J. SPAFFORD, Allen (A 1927), Wood Conversion Coi, Cloquet, Minn. SPECKMAN, Charles H. (Af 1918), Prof., Engr., 375 Bourse Bldg., Philadelphia, Pa. SPELLER, Frank N * (Af 1908), Director., Dept. of Metallurgy and Research (for mail), National Tube Co., 1922 Frick Bldg., and 6411 Darlington Road, Pittsburgh, Pa. SPENCE, Morton R. (7 1934), Asst. Purchasing Agent, Rundle & Spence Mfg. Co., 445 N. Fourth St., and (for mail), 709 E. Lexington Blvd., Milwaukee, Wis. SPENCE, Robert T. (A 1935), Engrg. Mgr., Pflugradt Co.. 215 W. Kilbourn, and (for mail), 2402 South 68th St., West Allis, Wis. Warm Air Heater Co., Dowagiac, Mich., and (for SPENCER, J. Boyd (Af 1935), Pres, and Chief mail), 248 Roche St.. Huntington, Ind. Engr. (for mail), Spencer Cooling & Air Cond., SMITH, Jared A. (A 1933), Distributor (for mail). Co., 1201 S. Third St., and 2215 Humboldt The Bryant Heater Co., 626 Broadway, and 3817 Ave. S., Minneapolis, Minn. Indian View Ave., Mariemont, Cincinnati, Ohio. SPENCER, RoUnd M. (7 1934), Sales Engr. (for SMITH, J. Darrell (Af 1933), Mech. Engrg. mail). Powers Regulator Co., 5009 Claremont Dept., Philadelphia & Reading Coal & Iron Ave., Houston, Texas, and 1269 Bonnie View. Co. (for mail), 317 North 19th St., Pottsville, Pa. Ave., Lakewood, Ohio. SMITH, Kenneth M. (S 1935), 334 Michigan E., Lansing, and (for mail), Y. M. C. A., Flint, Mich. SMITH, Lloyd E. (Af 1935), Asst. Mgr., Tech. SPIELMANN, Gordon P. (A 1931; 7 1923), VicePres. (for mail), Harrison-Speilmann Co., 480 _ Milwaukee Ave., Chicago, and 730 N. Prospect Dept., Frigidaire Corp., 300 N. Taylor St., and , (for mail), 1327 Amherst Place, Dayton, Ohio. SMITH, Milton S. (Af 1919), Treas., Buensod Stacey Air Conditioning, Inc., 60 East 42nd St., i New York, N. Y., and (for mail), 13 N. Terrace, Maplewood, N. J. SMITH, Robert Hugh (7 1934; S 1933), Sales Ave., Park Ridge, III. ' SPIELMANN, Harold J. (Af 1933), Air Cond. Engr., The Vilter Mfg. Co., 2117 S. First St., Milwaukee, Wis., and (for mail), 508 Elmore Ave., Park Ridge, 111. SPITZLEY, Ray L. (Af 1920), 1200 W. Fort St., . Engr., Sears Roebuck & Co., 33 E. Long St., Detroit, Mich. Columbus, Ohio. SPOELSTRA, William J- (Af 1935), Pres.. W. J. SMITH, Wilbur F. (Af 1920), Consulting Engr., J Spoelstra Co., Inc., 154 Parker Ave., Hawthorne, ' 600 Schuylkill Ave., Philadelphia, and (for mail), N. J. . 422 Bryn Mawr Ave., Cynwyd, Pa. SPOFFORTH, Walter (Af 1930). Chief of Mech. 'SMITH, William D. (A 1935), Pres, (for mail). Services (for mail), U. S. Penitentiary, McNeil W. D. Smith, Inc., 2147 Prospect Ave., and 17707 Island, and 1850 West Blvd., Day Island, Winslow Road, Cleveland, Ohio. SMOOT, Theo. H. (Af 1935), Chief Engr., Anchor Post Fence Co., Fluid Heat Div., Eastern Ave. and Kane St., and (for mail), 2512 Tacoma, Wash. . SPROULL, Howard E. (M 1920), Div. Sales Mgr. (for mail), American Blower Co.rp., 1005-6 American Bldg., and 3588 Raymar Drive, Talbot Road, Baltimore, Md. SMYERS, Edward C. (A 1933), Sales Engr., Minneapolis-Honeywell Regulator Co., 1013 Penn Ave., WUkinsburg, and (for mail), 148 Jamaica Ave., West View, Pittsburgh, Pa. SNEED, Richard B. (S 1934), 505 West 11th St., Bristow, and (for mail). College of Engrg., Cincinnati, Ohio. . " SPURGEON, Joseph H. (Af 1924), Salesman (for mail), Spurgeon Co., 5-203 General Motors Bldg., and 17215 Pennington Drive., Detroit, Mich. STACEY, Alfred E,, Jr.* (Af 1914). Wooton Road, Essex Fells, N. J. . STACK, Arthur E. (A 1935), Lab. Supervisor, University of Oklahoma, Norman, Okla. Washington Gas Light Co., 411 Tenth Ave, SNELL, Ernest (Af 1920). 3914 LeMay Ave., N.W., Washington, D. C,, and (for mail), 911 Detroit, Mich. Gist Ave., Silver Spring, Md. SNIDER, Lewis A. (Af 1927). Pres, (for mail). L. A. Snider Engrg. Service, Inc., 605 N. Michi STACY, Stanley C. (Af 1931), Mech. Engr., (for mail). Board of Education 13 S. Fitzhugh St., gan Ave., and 049-Buena Ave., Chicago, 111. and 91vCobbs Hill Drive, Rochester, N. Y. SNYDER, Allen K. (7 1930), Engr. in charge of . Air Cond.. Richmond Air Equipment Co., Inc., 1804 W. Broad St., and (for mail), 4309 Grove STALB, Joseph G. (A 1934), Eastern Sales Director, Dafl Steel Products Co., 155 East 44th St., New York, N. Y,, and (for mail), 22 Part Ave., Richmond. Va. ridge Ave., Ridley Park, Pa. SNYDER, Jay W. (Af 1917), McColl-Snyder- STAMMER, Edward L. (Af 1919), Supt., Htg. McLean, 23(M Penobscot Bldg., Detroit, Mich. SNYDER, Joseph S. (A 1925), Sales Repr., Detroit Lubricator Co., 374 Delaware Ave., and (for mail), 9 Knowlton Ave., Buffalo, N. Y. SODEMANN, Paul W. (Af 1926; 7 1920), Sales Engr., 2306 Delmar Blvd., and (for mail), 4136 Farlin Ave., St. Louis, Mo. SODEMANN, William C. B. (Af 1919), Pres, (for . mail), Sodemann Heat & Power Co., 2306 Del- mar Blvd., St. Louis, Mo. SONNEBORN, Charles (M 1930), Vice-Pres. in . charge of Production, Shaw-Perkins Mfg. Co., West Pittsburgh, and (for mail), R. D. No. 3, New Castle Pa SONNEY, Kermit J. (5 1934). L. B. 136, Wilcox, Pa., and-(for mail),' 316 W. Symmes St., Norman, Okla. and Vtg., Board of Education Bldg., and (for mail), 4430 Tennessee Ave., St. Louis, Mo. STANGER, Ralph B. (Af 1920), Owner (for mall), Robinson & Stanger, Empire Bldg., Pittsburgh, and Deer Creek Church Road, Glenshaw, Pa. STANGLAND, B. F. (<Charter Member), (2nd VicePres.. 1908; Board of Governors,- 1905-1906 1909; Board of Mgrs., 1895*1899; Council, 1896-1897), Retired, Kendall, N. Y. STANNARD, James M.* {Life Member; 1934; Af 1906), Pres-Treas. (for mail). Standard Power Equipment Co., 53 W. Jackson Blvd., Chicago, and 1402 Elinor Place, Evanston, 111. STAPLES, William H. (A 1924), Pres, (for mail). Wm. H. Staples, Inc., 154 West 20th St., and 548 West 164th St., New York, N. Y. 40 Roll of Membership STARK, W. Elliott* (M 1926), (Council, 1932 1935), Air Cond. Sales Dept., Bryant Heater Co., 17825 St. Clair Ave., Cleveland, and (for mail), 1875 Rosemont Road, East Cleveland, Ohio. STEELE, John B. (Af 1932), Chief Engr., Winni peg School Board, Ellen and William Aves., and (for mail), 184 Waterloo St.; Riverheights, Winnipeg, Man., Canada. STEELE, Maurice G. (Af 1929), Engr. (for mail). Revere Copper & Brass, Inc., Highlandtown P. O.. and 4109 Roland Ave., Baltimore, Md. STEEN, Joseph M. (Af 1929). Iron City Htg. Co., 843 Jacksonia St., Pittsburgh, Pa. STEENECK, Kenneth C. (7 1935), Htg. Engr., John G- Kelly Co., 210 East 45th St., New York, and (for mail), 9410-211th St., Bellaire, L. I., N. Y. . STEFFNER, Edward F. (7 1934), Htg. Engr., The Henry Furnace & Foundry Co., 3471 East 49th St., Cleveland, and (for mail), 1429 East 133rd St., East Cleveland, Ohio. STEGGALL, Howard B. (A 1934), Branch Mgr. (for mail), U. S. Radiator Corp., 951 Behan St. - N.W., and 1166 Murray Hill Ave., Pittsburgh, Pa. STEINHORST, Theodore F. (Af 1919), Treas., Gen Mgr., Emil Steinhorst & Sons, Inc., 612 South St., and (for mail), 1664 Brinckerhoff Ave., Utica, N. Y. STEINKELLNER, Edward J. (5 1935), 2162 South 32nd St., Milwaukee, Wis. STEINMETZ, C. W. Arthur (Af 1934), Mgr. (for mail), American Blower Corp., 249 High St., Newark, and 50 Oakwood Ave., Bogata, N. J. STENGEL, Frank J. (A 1935), Secy, (for mail). R. F. Stengel & Son, 76-80 Rosehill Place, and 50 Elmwood Ave., Irvington, N. J. STEPHENSON, L. A. (Af 1917), Mgr. (for mail). Powers Regulator Co., 409 East 13th St., and 801 West 57th Terrace, Kansas City, Mo. STERNBERG, Edwin (A 1932; 7 1931). Air Cond. Engr., Armo Cooling & Ventilating Co., 119 West 21st St., and (for mail), 58 East 92nd St., New York, N. Y. STERNE, Cecil M. (A 1934), Chief Engr. (for mail). Metropolitan Refining Co., Inc., 23-28 50th Ave., Long Island City, and 28 East 70th St., New York, N. Y. STETSON, Lawrence R. (Af 1913), 303 Congress St., Boston, Mass. STEVENS, Harry L. (Af 1934; A 1927; 7 1924). - Secy-Treas. (for mail), M. M. Stevens Co., 108 W; Sherman, and 7 West 22nd St., Hutchinson, Kan. STEVENS, John M. (A 1933), 4643 Morris St., Philadelphia, Pa. ' STILLER, Frederick Wilbur (7 1933), Estimator (for mail), F. C. Stiller & Co., 129 S. Tenth St., and 138 West 49th St., Minneapolis, Minn. STINARD, Rutherford L. (7 1934). Engr., American Radiator Co., 40 West 40th St., New York, N. Y., and (for mail), 1377 Boulevard E., West New York. N. J. STITT, Arthur B. (7 1935; 5 1933), Plbg. and Htg. Engr., Sears Roebuck & Co., 184 Atlantic St., Stamford. Conn., and (for mail), 610 West 139th St.. New York, N. Y. STITT, Eugene W. (Af 1917), State Supervisor "Stoko!" and (for mail). New Union House, Blairsville, Pa. STOCKWELL, William R. (Af 1903; 7 1901), Gen. Mgr., Mfg. Div., Weil-McLain Co., Michigan City, Ind. STONE, Eugene R. (Af 1913), 78 Woodbine St.. Quincy, Mass. ' STONE, George F. (Life Member; M 1918), Estimator, 16 Elmwooid Road, Verona, N. J. STRAKOSH, Walter C. (5 1935), 911 S. Fourth St., Champaign, 111. STRAUCH, Paul C. (A 1934), Sales Engr., Henry Furnace & Foundry Co., 18th and Merri- man Sts., Pittsburgh, and (for mail), 101 Wash ington Ave., Edgewood, Pittsburgh, Pa. STREVELL, Roger P. (Af 1934), Co-Partner (for mail), Wm. R. Hogg Co., 900 Fourth Ave., Asbury Park, and corner State Highway and Victor Place, Neptune, N. J. STRICKLAND, Albeit W. (A 1929), Htg. and Vtg. Engr., Big Timber, Mont. STRINGFELLOW, Jack C. (S 1935), (for mail), A. M. Lockett & Co., 305 Magnolia Bldg., Dallas, and 621 Virginia St., Terrell, Texas STROCK, Clifford (A 1929), Associate Editor (for mail). Heating and Ventilating, 148 Lafayette St., and 307 East 44th St., New York, N. Y. ' STROUSE, Sherman W* (A 1934), Sales Engr., Cooney Refrigeration, 493 Franklin St., and (for mail), 315 Capen Blvd., Buffalo, N. Y. STROUSE, Sidney B. (Af 1921), Engr. (for mail), : 500-529 Guarantee Trust Bldg., and 22 S. Illinois Ave., Atlantic City, N. J. STRUNIN, Jay (7 1933). Engr. and Contr. (for mail), Strunin Plbg. & Htg. Co., 408 Second Ave., and 54 West 89th St., New York, N. Y. STUART, Milton C. (Af 1935), Prof, (for mail). Dept, of Mech. Engrg., Lehigh University, and 505 Norway Place, Bethlehem, Pa. STUBBS, W. C. (Af 1934). Associate Naval Arch, (for mail), Norfolk Navy Yard-Bldg. 32 and 36 Channing Ave., Portsmouth, Va. SUMMERS, Ernest T. (A 1930). Pres, (for mail). Summers-Darling & Co., 121 Smith St., and STEVENS, William R. (A 1934), Partner, L. E. Ste. 22 Newcastle Apts.; Winnipeg, Man., ' Stevens Co., 442 E. Front St., Cincinnati, Ohio, '' Canada. . and (for mail), 159 Tremont Ave., Ft. Thomas, Ky. * . SUNDELL, Samuel S. (7 1935; S 1933), Engr., Larx Co., Inc., 607 S. Fifth Ave., and, (for mail), STEVENSON, Melvin J. (Af 1935), Sales Educa : 3040 Longfellow Ave., Minneapolis, Minn. tional Dept., Air Coed. Div., Frigidaire Corp., SUPPLE, Graeme B. (Af 1934), Sales Engr. (for ' and (for mail), 1824 Elsmere Ave., Dayton, Ohio. mail), American Blower Corp., 625 Architects and STEVENSON, Wilbur W. (Af 1928), Steam Htg. Builders Bldg., and 6224 Park Ave., Indianapolis, Engr. (for mail), Allegheny County Steam Htg. Ind. Co., 435 Sixth Ave.,-and 1125 Lancaster Ave., SUTCLIFFE, Arthur G. (Af 1922; A 1918), * Pittsburgh, Pa. Chief Engr., Ilg Electric Vtg. Co., 2850 N. Craw STEWART, Charles W. (Af 1919). Asst. Secy, (for ' mail), Hoffman Specialty Co:, Waterbury National Bank Bldg., and 21 Yates Ave., Water bury, Conn. .. STEWART, Clement W. (Af 1934), Sales Engr. (for mail), Ilg Electric Vtg. Co., 15 Park Row, : and 3985 Saxon Ave., New York, N.Y. STEWART, Duncan J. (Af 1935; A 1930), Mgr., . Electrical-Div. (for mail),'Barber-Golman-Co., . and 214 Franklin Place, Rockford, 111; STEWART, John C. (A 1934),Owner (for mail); - 1844 Smith St., and 2807 Victoria Ave:, Regina -Sask, Canada. -` STILL, Fred R * (Af 1904), {Presidential Member), (Pres., 1918; 2nd Vice-Pres., 1917; Council, 1916 -1919), Vice-Pres.- (for mail). American Blower ; Corp., 401 Broadway, and 1 East End Ave., New York, N. Y. ' f - ford Ave., and (for mail), 4146 N. St: Louis.Ave., .. Chicago, 111. . v- SUTHERLAND, David L. (A 1934), Pres-Treas. ;'-i-j"(for mad), Sutherland Air Cond. Corp.,: .627 Marquette Ave., and 1815 Colfax Ave. S., Minneapolis, Minn. . . SUTTON, Frank (Af 1932), Consulting Engr. (for mail), 140 Cedar St., New York, and Babylon, L. I., N. Y. ,' . SWANEY, Carroll R. (Af 1929; 7 1921), Gilbert Howe Gleason, 25 - Huntington Ave., .Boston, lilass * * SWANSON, Earl C. (A 1935). Research Engf. and Designer (for mail), Andersen Frame Corp:, ' Bayport, and 616 W. Mulberry St.; Stillwater, Minn. . . : . .'C l::* SWANSON, Harry (Af 1933), Engr. (fot-mail), The Fels Co.; 42 Union St;,-Portland', and-Box 135, Cape Cottage, Me. <- 41 American Society of Heating and Ventilating Engineers Guide, 1936 SWANSON, Rolf G. (5 1935), 324 Walnut St. TEMPLE, Walter J. (Af 1931), Engr., J. A. S.E., Minneapolis, Minn. Temple & Co., 919 E. Michigan Ave., and (for SWANSTROM, Alfred E. (J 1935; 5 1932), . mail), 1215 Reed St., Kalamazoo, Mich. Construction Foreman, U. S. Dept, of Interior, TEMPLIN, Charles L. (Af 1921), (for mail). and (for mail), 1444 Van Buren St., St. Paul, Carrier Engrg. Corp., 404 Bona Allen Bldg., and Minn. 781 Sherwood Road N.E., Atlanta, Ga. SWEATT, Charles H. (S 1935), 4259 Unity Ave., TENKONOHY, Rudolph J. (Af 1923). Vice-Pres. Robbinsdale, Minn. (for mail), Airtherm Mfg. Co., 1474 S. Varfde- SWEIVEN, C. E. (S 1935), 406 Walnut St. S.E., venter Ave., St. Louis, Mo., and 5019 Ridgewood Minneapolis, Minn. ' Ave., Detroit, Mich. SWENSON, John E. (A 1930), Industrial Engr. TENNANT, Raymond J. J. (A 1929), Supervisor (for mail), Minneapolis Gas Light Co., 800 of Sales (for mail), Duquesne Light Co., 435 Hennepin Ave., and 4853 South 14th Ave., Sixth Ave., and 529 Navato Place, Pittsburgh, Minneapolis, Minn. Pa. SWIFT, Paul F. (A 1935), Secy., Carl.F. Scheffer TENNEY, Dwight (Af 1932), Pres, and Chief Co., 838 S. Main St., and (for mail), 1115 Old Engr. (for mail), Tenney Engrg., Inc., Bloomfield Orchard Ave., Dayton, Ohio. Ave. at Grove St., Bloomfield, and 33 Summit SWISHER, Stephen G., Jr. (A 1934), Sales Road, Verona, N. J. Engr. (for mail). The Trane Co., 125 E. Wells THEORELL, Hugo G. T * (Life Member; Af 1902) St., and 4238 N. Woodboum Ave., Milwaukee, Consulting Engr., Hugo Theorells Ingeniflr- Wis. sbyra. Skoldungagatan 4, Stockholm, Sweden. SYSKA, Adolph G. (M 1933), Consulting Engr., THETFORD. James E. (5 1935). 7 Utopia Apts., ' Syska & Hennessy, 420 Lexington Ave., New Murphysboro, and (for mail), 303 S. Fifth St., York. N. Y. Champaign, 111. . SZEKELY, Ernest (Af 1920). Vice-Pres. and Gen. THINN, Christian A * (Af 1921), Chief Engr., Mgr. (for mail), Bayley Blower Co., 1817 South C. A. Dunham Co., 450 E. Ohio St., Chicago, 111. 66th St., and 3104 W. Kilbourn Ave., Milwaukee, THOMAS, L. G. Lee (Af 1934), Vice-Pres. (for Wis. mail). Economy Pumping Machinery Co., 3431 SZOMBATHY, Louis R. (A 1930), Pres., Fergu West 48th Place, Chicago, and 426 Forest Ave., son Sheet Metal Works, Inc., 34 N. Florissant Oak Park. III. Blvd., Ferguson, Mo.. THOMAS, Melvern F. (Af 1909), Consulting Engr. (for mail), Thomas & Wardeil, 229 College T St., and 24 Rivercrest Road, Toronto, Ont., Canada. TABOR, Charles B. (S 1935), 1815 University THOMAS, Norman A. (Af 1928), Pres, (for mail), ' Ave. S.E.. Minneapolis, Minn. Thomas Htg. Co., llth and Herrick Aves., and TAGGART, Ralph C * (Af 1912). 14 Lyon Ave., 824 Monroe Ave., Racine, Wis. Menands, Albany, N. Y. THOMAS, Richard H. (Life Member; M 1920), TALIAFERRO, Robert R.* (M 1919), Air Cond. Pres., Economy Pumping & Machinery Co., Engr., Philadelphia Saving' Fund Soc., 12 South 3431 West 48th Place, Chicago, III. . 12th St., Philadelphia, and (for mail), 838 THOMMEN, Adolph A. (A 1929), Metal Worker. Beechwood Road. Upper Darby, Pa. Htg. and Vtg., A. W. Leasing Sons, Inc.; 6632-36 TALLMADGE, Webster (Af 1924), Pres, (for W. Roosevelt Road. Oak Park, and (for mail), mail), Webster Tallmadge & Co., Inc., 255 North 3400 West 61st Place, Chicago, 111. 18th St., East Orange, and 7 Claremont Place, THOMPSON. Donald (J 1932), Engrg. Dept.. Montclair, N. J. ` Carbide & Carbon Chemicals Corp., and (for TARR, Harold M. (Af 1931), Htg. and Vtg. Engr., mail), 514 Simms St., Charleston, W. Va. ` 21 Montague St., Arlington Heights, Mass. THOMPSON, Edwin F. (A 1935). Draftsman. TASKER, Cyril (Af 1935), Research Fellow in E. I. DuPont de Nemours Co., Wilmington, Fuels (for mail), Ontario Research Foundation, Del., and (for mail), Atglen, Pa. 43 Queens Park, Toronto 5, and 737 Avenue Road, Toronto, Ont., Canada. TAUSON, Peter O. (Af 1935; $ 1934), Designing Engr., 1739 N.W. Eighth St., Oklahoma City, Okla. TAVANLAR, EUgio J * (J 1931), Carrier Re search Corp., 850 Frelinghuysen Ave., Newark, TAV^RNA, Frederick F. (Af 1928; A 1927; THOMPSON, Frank (Af 1935), Chief Engr.. Vulcan Iron Works, Ltd., and (for mail), 543 Newman St., Winnipeg, Canada. THOMPSON, Nelson S * (Af 1917; J 1897), 1615 Hobart St. N.W., Washington, D. C. THOMSON, Thomas N.* (Af 1899), Consulting Engr., 37 Irwin Place, Huntington, L. I., N. Y. THORNBURG, Harold A. (Af 1932; A 1932; J 1924), Engr., Raisler Heating Co., 129 Amster dam Ave., New York, and (for mail), 406-12th St., Union City. N. J. J 1929), Sales Engr. (for mail). Carrier Engrg. Corp., 12 South 12th St., and 2105 Chestnut St,, Philadelphia, Pa. TAYLOR, Edward M. (A 1934), Tech. Mgr., THORNTON, Roger T. (M1919), Sales Engr. (for Taylors, Ltd., 32A Lichfield St., and (for mail), mail), Buffalo Forge Co., 490 Broadway, and 46 102 Innes Road. Christchurch, New Zealand. Burbank Terrace, Buffalo, N. Y. TAYLOR, R. F. (Af 1915). Consulting Engr. (for THORNTON. William B * (Af 1931), Sales Engr. mail), 1305 Santa Fe Bldg., and 2515 Maple (for mail). Carrier Engrg. Corp., 404 Bona Allen Ave.. Dallas, Texas. Bldg., and 1310 Spring St. N.W., Atlanta, Ga. TAYLOR, William E. (A 1934). Factory Sales Engr., Air Cond. Div. (for mail). Gar Wood Industries, Inc., 7924 Riopelle St., and 2008 .W. Grand Blvd., Detroit, Mich. TAZE, Donovan L. (Af 1931), Sales Engr. (for mail), American Blower. Corp., 200 Division .Ave. N.. and 1621 Wealthy St- S.E., Grand Rapids. Mich. - TEAL, Edwin T. (JS 1935), Graduate Asst, (for mail), Dept, of Mech. Engrg., A. & M. College of Texas, College Station, and 6416 Velasco, Dallas, Texas. . TEASDALE, Lawrence A. (Af 1926)', Partner (for mail). Office of Hollis French, 20 Ashmun St., THRUSH, Homer A. (Af 1918), Pres.. H. A. Thrush & Co., 21-23 Riverside Drive, Peru, Ind. TIBBETS, John C. (Af 1920), Engrg. Dept., B. & O. R. R. Co., and (for mail), P. O. Box 106. Ellicott City, Md. TILLER, Louin (A 1935; S 1933), Air Cond. Engr., Oklahoma Gas & Electric Co., Third and Harvey, and (for mail), 1724 Northwest 20th St., Oklahoma City, Okla. TILTZ, Bernard E. (Af 1930), Pres, (for mail), Tiltz Air Conditioning Corp., 285 Madison Ave., New York, and 24 Barnum Road, Larchmont, N. Y. and 262 W. Rock Ave., New Haven, Conn. TIMMIS, Pierce (Af 1920), Service Equip. Dept, TEELING, George A. (Af 1930), Consulting (for mail). United Engineers & Constructors, Inc., Engr., Htg. and.Vtg., 11 N. Pearl St., Clarksville, 1401 Arch St., Philadelphia, and 202 Midland N. Y. Ave., Wayne. Pa. 42 Roll of Membership TIMMIS, W. Walter (Af 1933; A 1925). Mgr.. Product Development Sales Engrg. (for mail), American Radiator Co., 40 West 40th St., New York, and 32 Oak Lane, Glen Cove, L. I., N. Y. T1SNOWER, William (Af 1923). 131 Livingston St., Brooklyn, N. Y. TITUS, M. S. (Af 1928), Carbide & Carbon Chemical Corp., and (for mail), 124 Rosemont Ave., South Charleston, W. Va. TJERSLAND, Aif (Af 1916; J 1906). E. Sunde & Co., Ltd., Oslo, Norway. TOBIN, George J. (Af 1905), Owner (for mail), 187-191 North Ave., and 510 Grant Ave., Plainfield, N. J. TOBIN, John F. (A 1934), Salesman (for mail), American Blower Corp., Room 1404, 228 N. LaSalle St., and 2452 West 113th St., Chicago. III. TODD, Stanton W., Jr. (7 1935), Sales Repr., American Radiator Co., 506 Lyon N.E., Grand Rapids, Mich. TOONDER, Clarence L. (Af 1933), Air Cond. Engr., Sales Engrg. Dept., Kelvinator Corp., ' Plymouth Road, and (for mail), 12761 Strath- moor Ave., Detroit, Mich. . TORNOUIST, Earl L. (A 1934), Supervisor, Distribution Operation (for mail), Public Service Co. of North Illinois, 72 W. Adams St., Chicago, and 465 Parkside Ave., Elmhurst, 111. TORR, Thomas W. (Af 1933), Chief Engr., The Rudy Furnace Co., P. O. Box 73, Dowagiac, Mich. TORRANCE, Henry (Af 1933), Pres., 175 Christo pher St., and (for mail), 112 East 17th St., New York. N. Y. . TOUTON, R. D. (Af 1933), Tech. Director (for mail), Bayuk Cigars, Inc., Ninth and Columbia Ave., Philadelphia, and 19 Lodges Lane, Cynwyd, Pa. TOWER, Elwood S. (Af 1930), Engr., 1114 Kop- pers Bldg., and (for mail), 1411 Wightman St., Pittsburgh, Pa. TRANE, Reuben N.* (Af 1915), Pres, (for mail). The Trane Co., and 126 South 15th. LaCrosse, Wis. TRAUGOTT, Mortimer (A 1930), East Sales Mgr. (for mail), Bryant Heater & Mfg. Co., 152 North 15th St., Philadelphia, and 721 Meeting House Road, Elkins Park, Pa. TREADWAY, Quentin (7 1932). Sales Engr. (for mail), Clarage Fan Co., 707 Security Bank Bldg., and 2618 Collingwood, Toledo, Ohio. TROSKE, Joseph J. (A 1931), Vice-Pres. and Gen. Mgr. (for mail), Vander-Troske Co., 236 Winter Ave. N.W., and 233 Brown St. S.E., Grand Rapids, Mich. TROSTEL, Otto A. (Af 1935), Engr. (for mail), Kem Engrg. Co., 161 W. Wisconsin Ave., and 3155 N. Seventh St., Milwaukee, Wis. ' TRUITT, Joseph E. (Af 1920; A 1911), Pres., Autovent Fan & Blower Co., 1805 N. Kostner Ave., Chicago. 111. TRUMBO, Silas M. (A 1926), Sales (for mail), Buffalo Forge Co., 20 N. Wacker Drive, Chicago, and 921 Franklin St., Downers Grove, 111. - TRUMP, Charles C. (Af 1934), Pres, and M. E. (for mail), James Spear Stove & Htg. Co., 1823 Market St., Philadelphia, and 503 Baird Road, Merion, Pa. TURNER, George G. (A 1934), Western Repr., Heating and Ventilating (for mail). The In dustrial Press, Jnc., 22$ N. LaSalle St., Chicago, and 803 Elmwood Ave., Evanston, 111. TURNER, John (Af 1930), Sales Engr., Minne apolis-Honeywell Regulator Co., 285 Columbus Ave., Boston, Mass. TURNER, John W. (Af 1928), Chief Engr. (for mail). Pacific Steel Boiler Corp., Box 1488, Detroit, and 26031 Concord Road, Royal Oak, Mich. TURNER, Prescott K. (7 1935), Chief Engr.. Sawyer Lumber Co., Air Cond. Dept., 2 Kendall St.r and (for mail), 12 Dean St., Worcester, Mass. TURNO, Walter G. W. (Af 1917; A 1912), Secy.. H. W. Porter & Co., Newark, and (for mail), 71 Lafayette Ave., East Orange, N. J. TUSCH, Walter (Af 1917), Htg. and Vtg. Engr., Tenney & Ohmes, Inc., 101 Park Ave., New York, and (for mail) 881 Sterling Place, Brook lyn, N. Y. TUTTLE, George H. (7 1934), Htg. Engr. (for mail). The Detroit Edison Co., 2000 Second Ave., and 14242 Rutherford, Detroit. Mich. TUTTLE, J. Frank (Af 1913), Sales Agt. (for mail), Warren Webster & Co., Kewanee Boiler Corp., Boylston Steam Specialty Co., 127 Federal St., Boston, and 2 Elmwood Ave., Winchester, Mass. TUVE, George L * (Af 1932), Prof, of Heat. Power Engrg. (for mail). Case School of Applied Science, and 1294 Cleveland Heights Blvd., Cleveland, Ohio. TWIST, Charles F. (Af 1921). Pres, (for mail), Ashwell-Twist Co., 967 Thomas St., and 2310 Tenth Ave. N., Seattle, Wash. TYLER, Roy D. (M 1928), East Sales Mgr. (for mail), Modine Mfg. Co., 101 Park Ave., New York, and 15 Highbrook Ave., Pelham, N. Y. TYSON, William H. (Af 1928). Mgr. of Engrg. (for mail), Goodyear Tyre & Rubber Co., Ltd., and " Kipewa," Codsall Road. N.R., Wolver hampton, England. u UHL, Edwin J. (M 1925). Uhl Co.. 132 S. Tenth . St., Minneapolis, Minn. UHL, Willard F. (Af 1918), (for mail), Uhl Co., 132 S. Tenth St., and 4716 Lyndale Ave. S., Minneapolis, Minn. UHLHORN, W. J. (M 1920), 733 S. Highland Ave., Oak Park, 111. ULLMAN, Herbert G. (A 1928), Mgr., Mech Prod. Development Lab., American Radiator Co., P. O. Box 356, Second St. and Beechwood Ave., New Rochelle, and (for mail), 107 White Road, Scarsdale, N. Y. URDAHL, Thomas H, (Af 1930), Consulting Engr. (for mail), 726 Jackson Place N.W., and 1505-44th St. N.W., Washington, D. C. V; TUCKER, Frank N. (Af 1926), Field Engr., Ilg Electric Vtg. Co., Room 1108, 13 Park Row, New York, and (for mail), 239 Whaley St., Freeport, L. I., N. Y. .- TUCKER, Leonard A. (Af 1935), Chief Engr., J. J. Pocock, Inc., 1920 Chestnut St., Phila delphia, and (fdr mail), 518 Monroe Ave., Ardsley, Pa. TUCKERMAN, George E. (M 1932), Branch Mgr., Air Cond. Dept, (for mail), York Ice Machinery Corp., 1238-46 North 44th St., Philadelphia, and 502 Rodman Ave., Jenkintown, Pa. TURLAND, Charles H. (Af 1934; A 1930), Mgr., Htg. and Vtg. Dept., Kipp-Kelly, Ltd., 68 Higgins Ave., and (for mail), 325 Centennial St., Winnipeg, Man., Canada. VALE, Henry A. L. (Af 1929), Managing Director (for mail). Vale Co., Ltd., 141-43 Armagh St., Christ Church, and 241 Ham Road, Fendalton, Christ Church, New Zealand. VAN ALEN, Walter T. (Af 1924). Htg. and Sales Engr. (for mail), 1610 Seventh Ave., and 1300 - Darlington Road, Beaver Falls, Pa. VAN ALSBURG, Jerold H.* (Af 1931), Engr., Hart & Cooley Mfg. Co., and (for mail). Lock Box 903, Holland, Mich. VANCE, Louis G. (Af 1919), Partner, Vance- McCrea Sales Co., 2700 Sisson St., and (for mail) 3800 Hgerton Road, Baltimore, Md. VANDERHOOF, Austin L. (A 1933), Dist. Mgr. (for mail), Warren Webster & Co., 2341 Carnegie Ave., Cleveland, and 3120 Yorkshire Road, Cleveland Heights, Ohio. . 43 American Society of Heating and Ventilating Engineers Guide, 1936 VANDERLIP, P. J. (A 1935), Engr. (for mail). Oil Heating Co., 206 S. Grand Ave., and 501 S. Grand Ave., Lansing, Mich. VAN HORN, Howard T. (A 1933), Dist. Mgr., Detroit Stoker Co., 1217 McKnight Bldg., and (for mail), 4537 Grand Ave., Minneapolis, Minn. VARNER, John L. (A 1935), Air Cond. and Comm. Engr. (for mail). The Jacksonville Refrigeration Co., Inc., 35 W. Monroe St., and 3807 St. Johns Ave., Jacksonville, Fla. VAUGHAN, John G., Jr. (/ 1935), Sales Engr. (for mail), American Radiator Co., Fourth and Channing Sts. N.E., Washington, D. C., and 3515-36th St., Mt. Rainier, Md. VERMERE, Earl J. (Af 1929), Sales Engr., Kewanee Boiler Corp., Warren Webster & Co., 2341 Carnegie Ave., Cleveland, and (for mail), 2325 Wyandotte Ave., Lakewood, Ohio. VERNON, J. Rexford (Af 1928; A 1926), (for mail), Johnson Service Co., 1355 Washington Blvd., Chicago, and 733 Brummel St., Evanston, 111. VETLESEN, G. Unger (Af 1930), 3 East 84th St.f New York, N..Y. VIDALE, Richard (Af 1935), Air Cond. Engr. (for mail), Quinby Air Cond. Corp., 618 E. Main St., and 572 Flower City Park, Rochester, N. Y. VINCENT, Paul J. (Af 1931), P. J. Vincent Co., 2133 Maryland Ave., and (for mail), 3807 Beech Ave., Baltimore, Md. VINSON, Neal L. (S 1932), Junior Engr. Drafts man (for mail), U. S. Navy Yard N.W., 1629 K St., Washington, D. C., and Box 3007 Lowell. Ariz. VIVARTTAS, E. Arnold (M. 1910), Consulting Engr., 285 Hawthorne St.-, Brooklyn, N. Y. VOGEL, Andrew (Af 1926), Engr. (for mail). General Electric Co., and 1821 Lenox Road, Schenectady, N. Y. - VOGELBACH, Oscar (Af 1923), Consulting Engr., Chamber of Commerce Bldg., Newark, and (for mail), 23 William St., North Arlington, N. J. VOGT, John H. (A 1925). Mech. Engr. (for mail), ' New York State Dept, of Labor, 80 Centre St., New York, and 87 Grant Ave., Brooklyn, N. Y. VOISINET, Walter E. (Af 1930), Sales Repr. (for mail), Buckeye Blower Co., 250 Delaware Ave., Buffalo, and 151 Warren Ave., Kenmore, N. Y. VOLK, Joseph H. (Af 1923), Pres, and Treas. (for mail), Thos. E. Hoye Htg. Co., 1906 W. St. Paul Ave., and 2965 South 43rd St., Milwaukee. Wis. VROOME, Albert E. (Af 1932), Air Cond. Engr., -Phoenix Engrg.'Corp., 2 Rector St., New York,- N. Y., and (for mail), 412 Morton Ave., Rutledge, Pa. w WACHS, Louis J. (/ 1930), Salesman, Carrier Engrg. Corp., Chrysler Bldg., New York, and (for mail), 354 East 21st St., Brooklyn, N. Y. WAECHTER, Herman P. (A 1930; J 1927), Air Cond. Engr., York Ice Machinery Corp., Brook lyn, and (for mail), 89 Sherman Ave., Tompkins- . ville, N. Y. WAGNER, A. M. (A 1921), Mgr. (for mail), American Radiator Co., 1741 W. St. Paul Ave., and 1857 N. Prospect Ave., Milwaukee, Wis. WAGNER, Frederick H., Jr. (Af 1934), VicePres, (for mail), Niagara Blower Co., 6 East 45th St., New York, and 1126 Post Road. Scarsdale, N. Y. WAITE, Harry (A 1929), Secy-Treas. (for mail), Gray Plbg. Co., 1214 Ogden Ave., and 1409-17th St., Superior, Wis. WALDON, Charles D. (A 1932), Consulting Engr., Spencer Foundry Co., Penetang,. Ont., and (for mail), 32 Femdale Ave., Toronto, Ont., Canada. WALKER, Alexander (A 1925), Branch Mgr. (for -mail), C. A. Dunham Co., Ltd., 1307 Fifth St. ;w... and 603-13th Ave. W., Calgary, Alta., Canada. WALKER, Edmund R. (Af 1934), Sales Mgr., Htg. Div. (for mail), Fedders Mfg. Co., Inc., 57 Tonawanda St., and 696 Crescent Ave., Buffalo, N. Y. WALKER, J. Herbert* (Af 1916), Supt. of Central Htg. (for mail), The Detroit Edison Co., 2000 Second Ave., Detroit, and 432 Arlington Road, Birmingham, Mich. WALKER, William K. (Af 1935), Development Engr., American Radiator Co., 40 West 40th St., New York, N. Y. WALLACE, George J. (Af 1923), Principal Engr. and Contractor, 96-19-35th Ave., Corona, and (for mail), 27-36 Ericsson St., East Elmhurst, N. Y. WALLACE, James B. (A 1935), Dist. Repr., Taco Heaters, Inc., 342 Madison Ave., New York, N. Y., and (for mail), 16921 Sorrento, Detroit, Mich. . WALLACE, Kenneth S. (Af 1931), Heating Engr., Peoples Gas Light & Coke Co., 1520 Milwaukee Ave., and (for mail), 6259 Sheridan Road, Chicago, 111. WALLACE, William M., 2nd (Af 1929), Asst. Zone Mgr., Industrial Materials Div., Owens- Illinois Glass Co., Chrysler Bldg., New York, and (for mail), 8908-196th St.. Hollis, L. I., N. Y. WALLICH, A. C. (Af 1919), Universal Cooler Corp., Green and Melville, and (for mail), 1667 Burlingame, Detroit, Mich. WALSH, Edward R., Jr. (A 1935), Mgr., Sales, ' Gilbert & Barker Mfg., Springfield, and (for mail), 100 Church St., W. Roxbury, Mass. WALSH, James A. (A 1932; J 1929), Sales Mgr. (for mail), Peirce-Phelps, Inc., Fifth and Noble Sts., and 6500 Wissahickon Ave., Philadelphia, Pa. WALTERS, Arthur L. (Af 1926; A 1925; J 1924). 7284 Richmond Place, Maplewood, Mo. . WALTERS, William T. (Af 1917), Engr., Illinois Engrg. Co., Corner 21st St. and Racine Ave., and (for mail), 7965 Phillips Ave., Chicago, 111. WALTHER, Vernon H. (Af 1928; J 1925), Mech. Engr., 6821 Osceola Ave., Edison Park, Chicago, 111. WALTERTHUM, John J. (A 1922), Htg. and Vtg. Contractor, 212 East 58th St., New York, N. Y., and (for mail), 42-a Van Reipen Ave., Jersey City, N. J. WALTON, Charles W., Jr. (Af 1934), Mech. Engr. (for mail). Rockefeller Center, Inc., 30 Rockefeller Plaza, New York, N. Y., and 120 Monte Viste Ave., Ridgewood, N. J. WANDLESS, Franklin W. (Af 1925), Registered Engr. (for mail), 1518 Fairmount Ave., Phila delphia, and Berwyn, Pa. WARD, Frank J. (Af 1935), Owner, Frank J, Ward Co., Cold Spring, Ky. WARD, Oscar G. (Af 1919), Dist. Repr. (for mail). Johnson Service Co., 1230 California St., and 1607 Jasmine St., Denver, Colo. -. WARDELL, Arthur (Af 1935), Partner (for mail), Thomas & Wardell, 229 College St., and 124 Melrose Ave., Toronto, Ont., Canada. WARING, i. M. S. (Af 1932), Consulting Engr. (for mail). Chase & Waring, 17 East 42nd St., and 277 Park Ave., New York, N. Y.. . WARREN, Charles W. (S 1935), Mech. Engr. (for mail), A. J. Warren, 2313 Ave. E, and 3317-RH, Galveston, Texas. WARREN, Clarence N. (Af 1919), Vice-Pres., Hayes Bros., Inc., 236 W. Vermont St., and (for mail), 419 East 48th St., Indianapolis, Ind. WARREN, Francis C. (Af 1934), Salesman (for mail), American Blower Corp., 228 N. LaSalle. St., Chicago, and 127 East Ave., Park Ridge, 111. WARREN, Harry L. (Af 1930), Htg. Engr., Southern California Gas Co., 950 S. Broadway, Los Angeles, and (for mail), 1303 Huntington Drive, South Pasadena, Calif. . WASHBURN, Marcus J. (A 1934), Insulation Engr. (for mail), Eagle-Picher Lead Co., Temple Bar Bldg., and 2211 Park Ave., Cincinnati, Ohio. 44 Roll of Membership WASHINGTON, George (M 1934). Sales Engr. (for mail), Hoffman Specialty Co., 130 N. Wells St., Chicago, and 4327 Johnson Ave., Western Springs, 111. WASHINGTON, Laurence W. (Af 1929). VicePres. (for mail). National Regulator Co., 2301 Knox Ave., Chicago, and. 778 Laurel Ave., Des Plaines, 111. WATERMAN, John H. (Af 1931), Engr. ffor mail), Chas. T. Main, Inc., 201 Devonshire St., Boston, and 7 Centre St., Cambridge, Mass. WATERS, George G. (Af 1931; A 1926), Dist. Mgr. (for mail), American Blower Corp., 1433 Oliver Bldg., 'and 52 Vernon Drive, Pittsburgh (16). Pa. WATSON, H. Dalton {A 1935), Br. Mgr. (for mail), Linde Canadian Refrigeration Co., 124 King St., and 61 Furby St., Winnipeg, Man., Canada. . WATSON, M. Barry (Af 1928), Consulting Engr., 121 Welland Ave., Toronto, Ont., Canada. WAUNG, Tsing-fi (Af 1935; / 1933), Htg. Engr. (for mail), Andersen, Meyer & Co., Ltd., Yuen Ming Yuen Road, and 16 Lane, 152 Edinburgh Road, Shanghai, China. WEATHERBY, Edward P., Jr. (S 1935), 813 N. Zangs Blvd., Dallas, Texas. WEBB, Ernest C. (Af 1935), Engrg. Service Mgr., Iron Fireman Mfg. Co., 3170 West 106th St,, . Cleveland, and (for mail), 1202 Woodside Ave., Rocky River, Ohio. WEBB, John S. (Af 1920), Sales Mgr., Webster Talltnadge Co., Inc;, 300 Madison Ave., New : York, N. Y., and (for mail), 345 Brookline St., Needham, Mass. - WEBB, John W. (Af 1926), Managing Dir. (for mail), Webb Dust Removing & Drying Co.. Ltd., Princess and Park St. Works, and "Ebor." Brinnington, Stockport, England. WEBSTER, E. Kessler (Af 1915), Warren Webster & Co., 17th and Federal Sts., Camden, N. J. WEBSTER, Warren (Life Member. 1933; Af 1906; A 1899), Pres., Warren Webster & Co., 17th and Federal Sts., Camden, N. J. WEBSTER, Warren, Jr. (Af 1932; A 1932; J 1927), Vice-Pres-Treas. (for mail), Warren Webster & Co., 17th and Federal Sts., Camden, and Washington Ave. and Colonial Ridge, Haddonfield, N. J. WEBSTER, William H., Jr. (A 1935), Vice- Pres. (for mail), Hurst Heating Engrs., Inc., 400 York St., and 625 Maryland Ave., Norfolk, Va. WECHSBERG, Otto (Af 1932), Pres, and Gen. Mgr., Coppus Engrg. Corp., 344 Park Ave., and (for mail), 1006 Main St., Worcester, Mass. WEGMANN, Albert (Af 1918), 6206 North 17th St., Philadelphia, Pa. WEIL, Martin (A 1925), Vice-Pres. (for mail), Weil-McLain Co., 641 W. Lake St., and 4259 Hazel Ave., Chicago, 111. . WEIL, Maurice I. (A 1928), Pres, (for mail), , Chicago Pump Co., 2336 Wolfram St., and 1409 Elmdale Ave., Chicago, 111. WEIMER, Fred G. (A 1919), Salesman, Kewanee Boiler Corp., 1741 W. St. Paul Ave., and (for mail), 3958 N. Stowell Ave., Milwaukee, Wis. WEINSHANK, Theodore* (Life Member 1933; Af 1906), (Board of Governors, 1913), Con sulting Engr., 3307 Belden Ave., Chicago, 111. WEISS, Arthur P. (Af 1928), Burnham Boiler Corp., Irvington, and (for mail), 134 Farrington Ave., North Tarrytown, N. Y. WEISS, Carl A. (A 1924), Supt. (for mail), Kombrodt Kornice Ko., 1811 Troost Ave., and 29 East 68th St., Kansas City, Mo. WEITZEL, Paul H. (S 1934), Cameron B. Weitzel, 122 E. High St., Manheim, Pa. ` WELCH, Louis A., Jr. (A 1929), 443 Second St., Schenectady, N. Y. WELDY, Lloyd O. (Af 1930), Sales Engr. (for mail). The Powers Regulator Co., 2720 Greenview Ave,, and 2846 North 77th Ave., Chicago, III. WELSH, Harry S. (Af 1906), Sales Engr., Weil- McLain Co., and (for mail), 53 Kemphurst Road, Rochester, N. Y. WELTER, M. A. (A 1925), (for mail). Twin City Furnace Co., 410-12 W. Lake St., and 4306 Garfield S., Minneapolis, Minn. WENDT, Edgar F. (Af 1918). Pres, (for mail), Buffalo Forge Co., 490 Broadway, and 120 Lincoln Pkwy., Buffalo, N. Y. WEST, Perry* (Af 1911), (Council, 1920-1925; Treas., 1924-1925), Consulting Engr. (for mail), 13 Central Ave., and 445 Ridge St., Newark, N. J. WETZELL, Horace E. (Af 1934), Chief Engr. (for mail). The Smith & Oby Co., 6107 Carnegie Ave., and 8796 Elsmere Drive, Cleveland, Ohio. WHALLON, Fletcher (S 1935), 3852 Lyndale Ave. S., Minneapolis, Minn. WHEELER, Otto J. (Af 1923), Pres-Treas. (for mail). The Samuel A. Esswein Htg. & Plbg. Co., 548-558 W. Broad St., and 2044 CollingswoodRoad, Columbus, Ohio. WHELLER, Harry S. (Af 1916), Vice-Pres., L. J. Wing Mfg. Co., 154 West 14th St., New York, and (for mail), 725 Union Ave., Elizabeth, N. J. WHITE, Eugene B. (Af 1934), Arch, and Engr. (for mail), Y. M. C. A., 19 S. LaSalle St., Chicago, and 309 N. Taylor Ave., Oak Park, 111. WHITE, Elwood S. (Af 1921), Pres, (for mail). Taco Heaters, Inc., Room 1224, 342 Madison Ave., New York, N. Y., and Meadowbank Road, Old Greenwich, Conn. WHITE, Everett A. (Af 1921), Engrg. Dept., Crane Co., 30 South 16th St., and (for mail), 5244 Nottingham St., St. Louis, Mo. WHITE, John G. (Af. 1932), State Power Plant Engr. (for mail), 624 E. Main St., and 622 E. Main St., Madison, Wis.- ' WHITELAW, H. Leigh (Af 1916), Vice-Pres. (for mail), American Gas Products Corp., 40 West 40th St., New York, N. Y., and Overbrook Lane, Darien, Conn. WHITELEY, Stockett M. (Af 1933), Consulting Engr. (for mail), Baltimore Life Bldg., and 3931 Canterbury Road, Baltimore, Md. WHITMER, Robert P. (Af 1935), Secy, (for mail), American Foundry & Furnace Co., 915 E. Washington St., and 1402 E. Washington St., Bloomington, 111. WHITNEY, C. W. (Af 1935), Mgr., Trilling & Montague, 24th ana Walnut Sts., Philadelphia, and (for mail), Apt. F-l, Sevilla Court, BalaCynwyd, Pa. WHITTAKER, Wayne K. (A 1935), Htg.-Vtg. Maint., Irving Trust Co. Bldg., 1 Wall St., New York, and (for mail), 198-40-32nd Ave., Flush ing, L. I., N. Y. . WHITTALL, Ernest T. (A 1933), Vice-Pres., May Oil Burner of Canada, Ltd., 17 Elm St., and (for mail), 11 Cottingham Road, Toronto, Ont., Canada. WIEGNER, Henry B. (Af 1919), Mgr.. Boston Office, Johnson Service Co., 20 Winchester St., Boston, and (for mail), 143 Standish Road, Watertown, Mass. . . WIERENGA, Peter O. (A 1931), Vice-Pres. (for mail), C. C. James Co., 49 Coldbrook St. N.E., and 231 Brown St. S.E., Grand Rapids, Mich. WIGGINS, Oswald J. (/ 1935; S 1933), Engr., Moran & Co., 602 Globe Bldg., St. Paul, and (for mail), 1629 Sixth St. S.E., Apt. 8, Minneapolis, Minn. . '' WIGGS, G. Lome (A 1932; J 1924), Consulting Engr. (for mail). University Tower, and 4797 Grosvenor Ave., Montreal, P. Q., Canada. WIGLE, Bruce M. (A 1926). Pres, (for mall), Bruce Wigle Plbg. & Htg. Go., 9117 Hamilton . Ave., and 18114 Oak Drive, Detroit, Mich. WILDER, Edward L. (Af 1915), Mgr., Gas Sales .(for mail). Utility Management Corp., 150 Broadway, New York, and 12 Mereland Road, New Rochelle, N. Y. . 45 American Society of Heating and Ventilating Engineers Guide, 1936 WILEY, Edgar C. (Af 1909), Wiley & Wilson. Lynchburg, Va. WILHELM, Joseph E. (5 1934), 1355 West 87th, Cleveland, Ohio. WILKINSON, Farley J. (Af 1933), Mgr., Engrg. Service, Montgomery Ward & Co., and (for mail), 18257 Martin Ave., Homewood. 111. WILLARD, Arthur C * (M 1914). (Presidential Member), (Pres., 1928; 1st Vice-Pres., 1927; 2nd Vice-Pres., 1926; Council, 1925-1929), (for mail). President, University of Illinois, and 711 Florida Ave., Urbana, 111. WILLEY, Earl C. (M 1934), Mech. Engrg. Instr., Oregon State College, and (for mail), 1652 "A" St., Corvallis, Ore. WILLIAMS, Allen W. (A 1915). Managing Director (for mail). National Warm Air Htg. & Air Cond. Association, 50 W. Broad St., Colum bus, and 51 Meadow Park Ave., Bexley, Ohio. WILLIAMS. Clinton R. (M 1935). Draftsman, E. I. DuPont de Nemours Co., Wilmington, . Del., and (for mail), 155 Primes Ave., Folcroft, Pa. WILLIAMS, Frank H. (J 1934), Air Cond. Tester, Frigidaire Div., General Motors, and (for mail), 118 Maplewood Ave., Dayton, Ohio. WILLIAMS, J. McFarland, Jr. (A 1928; J 1927), Sales Engr., l407-35th St. N.W., Washington, D. C. WILLIAMS, J. Walter (Af 1915), Pres, (for mail). Forest City Plbg. Co., 332-36 East State St., and 923 E. State St., Ithaca, N. Y. WILLIAMS, Leo E. (A 1933; J 1930), Viscose Co., and (for mail), 827 Liberty St., Meadville, Pa. WILLIS, Leonard L. (S 1935), Engr., Conrad Refrigeration Co., 17 E. Hennepin, and (for mail), 1212 Oliver N., Minneapolis, Minn. WILMOT, Charles S. (M 1919), (for mail). Building Insulation Co., 106 South 16th St., Philadelphia, and 406 Essex Ave., Narberth. Pa. WILSON, George T. (M 1925), Sales Engr., Gurney Foundiy Co., Ltd., 4 Junction Road, Toronto, and (for mail). Tyre Ave., Islington, OnL, Canada. WILSON, Harold A., Jr. (J 1933). Gen. Sales Dept., American Radiator Co., 40 West 40th St., and (for mail), 1133 Park Ave., New York, N. Y. WILSON, James W. (S 1935), 3603 Cole Ave.. O&llas exas WILSON, Raymond W. (M 1934), Member of Firm (for mail), Wilson-Brinker Co., 412 Pythian Bldg., and 429 Creston Ave., Kalamazoo, Mich. WILSON, W. H. (A 1932), Steamfitter Foreman, Pullman-Standard Car Mfg. Co., 11001 Cottage Grove Ave., and (for mail), 22 West 110th Place, . Chicago, 111. WILSON, William H. (A 1923), Branch Mgr. (for mail). Johnson Service Co., 507 E. Michigan St., and 2023 E. Olive St., Milwaukee, Wis. WILTBERGER, Constant F. (M 1935), Mech. Engr., Stewart A. Jellett Co., 1200 Locust St., and (for mail), 2650 N. Ninth St., Philadelphia, Pa. WINANS, Glen D. (Af 1929), Engr. of Steam Distribution (for mail), The Detroit Edison Co., 2000 Second Ave., and 16183 Wisconsin, Detroit. Mich. WINOUIST, Walter J. (A 1930), Htg. and Vtg. ` Engr., 294 Nostrand Ave., Brooklyn, N. Y. WINSLOW, C.-E. A.* (M 1932), Prof, of Public Health (for mail), Yale University, 310 Cedar . St., and 314 Prospect St., New Haven, Conn. WINTERBOTTOM, Ralph F. (M 1923), Htg. Engr., Winterbottom Supply Co., Commercial and Miles, and (for mail), 1002 Riehl St., Water loo, Iowa. - WINTERER, Frank C. (M 1920), Sales Mgr. (for mail), Cochran Sargent Co., Broadway and Kellogg Blvd., and 836 Juno St., St. Paul, Minn. WINTHER, Anker .(/ 1932), Air Cond. Engr., York Ice Machinery Corp., 2116 Gilbert Ave., Cincinnati, Ohio. WISE, Daniel E. (S 1934), 400 Temple St., New Haven, Conn. WITMER, Charles N. (J 1930), Dist. Dealer Supervisor (for mail). Carrier Engrg. Corp., 2022 Bryan St., and 4154J Prescott St., Dallas, Texas. WOESE, Carl F. (M 1934), Consulting Engr. (for mail), Robson & Woese, Inc., 1001 Burnet Ave., and 256 Robineau Road, Syracuse, N. Y. WOHL, Maurice W. (M 1934), 100 Linden Blvd., Brooklyn, N. Y. WOLF, John C. (M 1923), Draftsman and Engr. (for mail), B. F. Sturtevant Co., and 76 Beacon SL, Hyde Park, Mass. WOLF, Philip (Af 1935), Prop., City Contracting Co.. 2025 Fifth Ave., New York, N. Y. WOLFERT, Edward R. (M 1935). Section Engr. (for mail), Westinghouse Electric & Mfg. Co., East Springfield, and 119 Windemere St., Springfield, Mass. WOLFF, Peter P. (M 1935), Engr., Bell & Gossett Co., 3000 Wallace St., and (for mail), 7058 Rhodes Ave., Chicago, 111. WOOD, Frederick C. (J 1931), Sales Engr., Air Cond. (for mail), Airtemp, Inc., Div. Chrysler Motors, 8021 Conant Road, and 16220 Nor mandy, Detroit, Mich. WOOD, J. Sydney (M 1926), Estimator (for mail), Bennett & Wright, Ltd., 72 Queen St. E., and 163 Briar Hill Ave., Toronto, Ont., Canada. WOODMAN, Lawrence E. (M 1934), Pres, (for mail). Woodman Appliance & Engrg. Corp.. 203 E. Capitol, and 1014 Fairmount, Jefferson City, Mo. WOODS, Edward H. (Af 1934). Prop, (for mail), F. H. Higgins, 311 E. State St. and Hook Place, Ithaca. N. Y. WOOLLARD, Mason S. (M 1934), Draftsman, H. H. Angus, Consulting Engr., 1221 Bay St., and (for mail), 31 Hillcrest Park Ave., Toronto, Ont., Canada. WOOLSTON, A. H. (M 1919), Chief Engr. (for mail). Bowere Bros. & Co., 2015 Sansom St., and 4815 North 12th SL, Philadelphia, Pa. WORSHAM, Herman (M . 1925; J 1918). (for mail), Frigidaire Corp., 224 West 57th St., New York. N. Y., and 103 N. Walnut SL, East Orange, N. J. WRIGHT, Clarence E. (J 1935; 5 1933), Htg. and Vtg. Engr., Fairmont Wall Plaster Co., and (for mail). Locust Ave. Ext., Fairmont, W. Va. WRIGHT, Kenneth A. (M1921), Mgr. (for mail), Johnson Service Co., 1113 Race SL, Cincinnati, Ohio, and 113 Orchard St., Ft. Mitchell, Ky. WRIGHT, M. Birney (A 1932; J 1929), Mech. Engr., E. I. duPont deNemour & Co. (for mail). Route 1 Box 78-C, Charleston. W. Va. WRIGHT, William J. (S 1935), 1111 W. Illinois St., Urbana, III. WUNDERLICH, Milton S.* (Af 1925), Mech. Engr.,.The Insulite Co., 1100 Builders Exchange, Minneapolis, and (for mail), 545 Mount Curre Blvd., St. Paul, Minn. WYLIE, Howard M. (Af 1925; J 1917), VicePres. in charge of Sales (for mail), Nash Engrg. Co., and 51 Elmwood Ave., South Norwalk, Conn. Y YAGER, John J. (Af 1921), 425 Woodbridge Ave., Buffalo, N. Y. YAGLOU, Constantin P.* (Af 1923), Asst. Prof, of Industrial Hygiene (for mail), Harvard School of Public Health, 55 Shattuck St., Boston, and 10 Vernon Road, Belmont, Mass. YATES, George L. (S 1934), Instructor, Dept, of 011 and Gas Prod, (for mail). University of. Pittsburgh, Pittsburgh, Pa., and 1220 Johnstone, Bartlesville, Okla. , YATES, James E. (Af 1934), Mgr. (for mail), Yates Neale & Co., 231 Tenth St., and 431-16th St., Brandon, Man., Canada. 46 Roll of Membership YATES, Walter (Life Member 1934; M 1902). Governing Dir. (for mail), Matthews & Yates, Ltd., Cyclone Works, and Parksend Swinton',, Man., England. YOUNG, Emil O. (A 1935). Pres.-Treas. (for mail), The Young Ventilating Co., 2703-7 Wood land Ave., and 2040 East 83rd SL, Cleveland. Ohio. `z ZACK, Hans J. (Af 1928), Mgr., The Zack Co., 2311 Van Buren SL, Chicago, 111. ZANGRILLI, Albert J. (S 1935), 537 Turrett St., Pittsburgh, Pa. ZIBOLD, Carl E. (Af 1929), Mech. Engr., Htg. and Vtg., 13 Chadwick Road, Westminster Ridge, White Plains, N. Y. ZIESSE, Karl L. (A 1931), Secy-Treas. (for mail), Phoenix Sprinkler & Htg. Co., 115 Campau Ave. N.W., and 315 Hampton Ave. S.E., Grand Rapids, Mich. Z1EBER, William E. (Af 1935), Asst. Chief Engr. (for mail), York Ice Machinery Corp., Roosevelt Ave., and 112 S. Penn St., York, Pal ZIMMERMAN, Alexander H. (A 1930), Venti lation Engr., Chicago Board of Health, 707 City Hall, and (for mail), 5147 N. SL Louis Ave., Chicago, 111. ZINK, David D. (Af 1931). Consulting Engr., Owner (for mail), 225 Plaza Theatre Bldg., Kansas City, and Hickman Mills, Mo. ZOKELT, C. G. (Af 1921), Consulting Engr., 3810-24th Ave. S., Seattle, Wash. . ZUHLKE, William R. (Af 1928), 530 ` McLean Ave., Yonkers, N. Y. 47 Summary of Membership (Corrected to January 1, 1936) UNITED STATES AND ISLAND TERRITORIES Alabama...... .._.................................... . 2 Nebraska.......... .................................... 2 Arizona....______________ :.................. 2 New Hampshire..... :................ 1 Arkansas....... .._................................... 3 New Jersey________________ 105 California..... ...................................... :: 40 New York............................ 362 Colorado............ 5 North Carolina.-...................... 9 Connecticut.............. 33 North Dakota..............:................ ..... 1 Delaware.-.................................... 6 Ohio--___ ____________ 105 District of Columbia............ ................26 Oklahoma.............................. --....... 28 Florida 7 Oregon................ 1 Georgia___ __ 11 Pennsylvania... .......................... 225 Hawaii................................. 1 Phillipine Islands.......................... 2 Illinois________ ___________: 230 Rhode Island.-.................................... 5 Indiana..... .................... 18 South Carolina..................................: 2 Iowa........................... Kansas.______________ ____________ Kentucky.....________ _____________ 8 South Dakota............. 1 5 Tennessee .............-......................... 6 8 Texas..................................... 38 Louisiana..... ...................... 8 Utah...............:...................................... 1 Maine.___________________ 4 Vermont............................................... 3 Maryland.......................... 20 Virginia........... :.................................. . 15 Massachusetts............ 107 Washington.......... ............. 23 Michigan............ ..... Ill West Virginia........ .....:....... ............... 7 Minnesota............................................ 113 Wisconsin.-......... :......................... ..... 60 Missouri................................ 86 Montana____ : 4 1860 Canada.............. ...................................................... 115 FOREIGN COUNTRIES Australia... ......... Belgium........ ........... China___________________ Czechoslovakia 1 Denmark..--........................................ England____ .............. _....................... France. .......... ...... ..... .--;.............. Germany........................ India...................................................... Ireland__ ___ _1...........................;......... Italy--......................................................... 4 1 9 1 16 8 2 1 1 3 Japan.............................. _................... Mexico................................................ New Zealand..................................... Norway...................... Scotland.............. ;............................... South Africa.................................... i.. Spain............. Sweden........ ........ U. S. S. p....... ..................................... 5 3 3 2 1 2 2 3 1 Total Membership............ 69 2044 SUMMARY OF MEMBERSHIP BY GRADES Honorary Members............................................ ;.......... .... 1 Presidential Members.................................................. 24 Members.............. 1248 Associate Members.... ...................................................... 407 Junior Members.................................................................. 216 Student Members.................. ............. !................. .........,, 148 2044 48 LIST OF MEMBERS Geographically Arranged UNITED STATES and f ISLAND TERRITORIES ALABAMA Birmingham-- Fried, H. V. Lichty, C. P. ARIZONA Tucson-- Moreau, D. Phoenix-- Keys, L. F. ARKANSAS Fort Smith-- Herrick, L. Pine Bluff-- Pasadena-- Gifford, R. L. San Diego . Sadler, C. B. San Francisco-- Bouey, A. J. Cochran, L, H. Corrao, J. Haley, H. S. Hudson, R. A. Krueger, J. I. Leland. W. E. ' . ' South Gate-- Barnum, W. E., Jr. South Pasadena-- Warren, H.'L. . New London-- Chapin, C. G. .Forsberg, W. Hopson, W. T. Norwalk-- Mead, E. A. Riverside-- Murphy, J. R. South Norwalk-- Adams, H. E. Harvey, A. D. Jennings. I. C. Lyons, C. J. Wylie, H. M. Stamford-- Hoyt, L. W. Danielson, W. A. Downes, H. H. Febrey, E. J. Feltwell, R. H. Fife, G. D. Frankel, G. S. Gardner, S. F. Grimes, F. M. . Hewett, J. B. . Hood, O. P. Kiczales, M. D. Kingswell, W. Ei Mayette, C. E. Mullen, T. J., Jr. Ourusoff, L. S. Smallman, E. W. Thompson, N. S. Urdahl, T. H. Vaughan, J. G.( Jr. Vinson, N. L. Williams, J. M.t Jr. Greer, W. R. Siloam Springs--; Jones, C. R. CALIFORNIA COLORADO Colorado Springs--> Davis, A. F. Torrington-- . Doster, A. Kaczenski, C. Wallingford-- - FLORIDA Ft. Lauderdale-- Charlton, J. F. Beverly Hills-- Nelson, H. A, Glendale-- . Moon, F. L. Los Angeles-- Anderson, C. S. Jardine, D. C. Denver-- McQuaid, D. J. O'Rear, L. R. Ward. O. G. CONNECTICUT, Burns, J. R. Waterbury-- ' Ahlff, A. A. \ Davis O. E. Lincoln, R. L. Simpson, W. K. Stewart, C. W. . Jacksonville-- Varner, j. L. Miami-- Burke, W. J. Lingo, C- K. Munro, E. A. Pizie, S. G. . Binford, W. M. _ West Palm Beach-- Bullock, H. H. Cawby, E. L. . Cooper, A. W. Cranston, W. E., Jr. Edwards, H.-B. Bridgeport-^ ' Monroe, R. R. Smak, J. R. . Westport-- Goldschmidt, O. E. Hodeaux, W. L. GEORGIA Ellingwood, E. L. English, H. Fairfield-- _ DELAWARE Atlanta-- ' Hendrickson, H. M. Hill, F. M. ' Hogue, W. M. , Osborn, W. J. Greenwich--. . ' . Wilmington-- Gawthrop, F. H. Baker, C. T. . Clare, F. W. : Gouedy, K. E., Hungerford, L; KendaU, E. H. Jones, A. L. Opperman, E. F. Hayman, A. E., Jr. Kershaw, M..G. . Kagey, I. B.,.Jr. . Kent. L. F. Kennedy, M. . Kooistra, J. F. Lauer, H. B. Ness. W, H. C. : Hartford-- . . Millard, J. W. Lowhsbery, B. F. Ponsell, F. I. Schoenijahn, R. P. Klein, E. W. . Kuempel, L. L. . McKinney, W. J. Templin, C. L. . Orear, A. G. Ott. O. W. . . Manchester-- . . DISTRICT..OF ' Thornton,- W. B. Park, J. F. Pierce, E. D. : Polderman,L..H. ' Scofield, P. C. . Buck, L. New Haven-- Blakeley, H; J/ - " v COLUMBIA : Washington-- Augusta--` ' '. Arndt, H. W. . 1 . Simonds, A. H. Oakland-- ' Cummings, G. Ji Mears', L;. A. . Hughes,. C; E. Seeley, L. E. Teasdale, L.,A-v> \ Winslow, C;*E, A;:: Wise, p.\E. Apt. S. R. . . Beitzell, A. E. :'/ Brown, W. A.f .. Coward, H. DallaValle, J. M-, HAWAII/ : Honolulu--' Petersen, S. E. 4^ American Society of Heating and Ventilating Engineers Guide, 1936 ILLINOIS Bloomington-- MaGirl, W. J. Soper. H. A. Whitmer, R. P. Champaign-- Baur. J. W. Ficnerski. P. Hintz. H. P. Logan. T. M. Ransom, C. F. Strakosh, W. C. Thetford. J. E. Chicago-- Aeberly, J. J. Anderson, L. B. Arenberg, M. K. Baker, W. H., Jr. Baumgardner. C. M. Becker, W. A. Bishop, M. W. Black, F. C. Boehmer, A. P. Bolte, E. E. Borling, J. R. Bracken, J. H. Braun, L. T. Brigham, C. M. Broom, B. A. Brown, A. P. Brown, T. Carman, G. G. . Casey, B. L; " Christman, W. F. Christopbersen, A. E. Clegg, R. R. Close, P. D. Crone, C. E., Jr. Cunningham, T. M. Cutler, J. A. DeLand, C. W. Doherty, R. Dunham, C. A. Emmert, L. D. Ericsson, E. B. Evleth, E. B. Fatz, J. L. Finan, J. J, Fleming, J. P. Fleming. T. F. Foster, T. R. Frank, J. M. Freas, R. B. Gardner, W., Jr. Gaylord, F. H. Getschow, R. M. Gibbs. F. C. Goelz, A. H. Gossett, E. J. Gotschall, H. C. Graham, E. W. Graves, W. B. Haas. S. L. Haines, J. J. Hale. J. F. Hanley, T. F,, Jr, Hart, H. M. Hattis, R. E. Hayden, C. F. Hayes, J. J. Hayward.R. B. Hebley, H. F. J. Herlihy, J. J. Hill. E. V. . Hinckley, H. B. Hornung, J. C. Horton, H. F. Howatt, J. Howell, L. Hubbard, G. W. Hustoel, A. M. Jennings, W. G. Jenson, J. S. Johns, H. B. Johnson, C. W. Kaufman, C. W. Keeney, F. P. Kehm, H. S. Kreissl, H. G. Krez, L. Kyle, W. J. Lagodzinski, H. J. Lautenschlager, F. Lawler, M. M. Lees, H. K. Lewis, S. R. Lockhart, H. A. Machen, J. T. Malone. D. G. Malvin, R. C. Marschall, P. J. Martin, A. B. Matchett, J. C. Mathis, E. Mathis, H. Mathis, J. W. May, M. F. McCauley, J. H. McClellan, J. E. McDonnell, E. N. McFarland, W. P. Mcllvaine, J. H. Mehl, O. H. Mertz, W. A. Miller, F. A. Miller, R. T. Miliiken, J. H. Mittendorff* E. M. Mueller, H. C. Murphy, E. T. Narowetz, L. L., Jr. Needier, J. H. Neiler, S. G. Nelson, C. L. Newport, C. F. O'Brien, J. H. Offen, B. Olsen, C. F. Paul, L. O. Peller, L. Pitcher, L. J. Piwinski. E. J. Pope, S. A. Powers, F. W. Prentice, O. J. Presdee, C. W. Price, C. E. . Rasmussen, R. P. Raymond, F. I. Reger, H. P. Reid. H. P. Ries, L. S. Rietz, E. W. Rottmayer, S. I. Runkel, C. Scheidecker, D. B. Schweim, H. J. Seelig, L. Shultz, E. Snider, L. A. Spielman, G. P.. Stannard, J. M. Sutcliffe, A. G. Thinn, C. A. Thomas, L. G. L. Thomas. R. H. Thommen, A.' A. Tobin, J. F. Toroquist, E.L. Truitt, J. E. Trumbo, S. M. Turner, G. G. Vernon, J. R. Wallace. K. S. Walters, W. T. Walther, V. H. Warren, F. C. Washington, G. Washington, L. W: Weil. M. Weil, M. I. Weinshank, T. Weldy, L. O. White, E. B. Wilson, W. H. Wolff. P. P. Zack, H. J. Zimmerman, A. H. CiceroBrown, N. A. Keppner. H. W. Decatur-- Shorb, W. A. Elmhurst-- Potvin, L. J. Evanston-- Hayes, J. J. Maccubbin, H. A. Miller. J. E. Moore, R. E. Glen Ellyn-- Sherman, V. L. Homewood-- Wilkinson, F. J. Joliet-- Russell, W. B. Kewanee-- Bronson. C. E. Dickson, R. B. Hartman. J. M. Pursell, H. E. LaGrange-- Eaton, B. K. Linn, H. R. Lake Forest-- Moore, C. H. Scudder, B. Moline-- Beling, E. H. Nelson, H. W. Nelson, R. H. Otis, G. E. Mt. Vernon-- Benoist. L. L. Norwood Park-- Olson, B. Oak Park-- Blanding, G. H. Fitzgerald, M. J. May, E. M. Nightingale. G. F. Uhlhom. W. J. Park Ridge-- Heckel, E. P. Spielmann. H. J. Peoria-- Baird, S. A. Farnsworth, J. G. Meyer, F. L. Rockford-- Braatz, C. J. Dewey, R. P. Merwin. G. E. Sharp, H. C. Stewart, D. J. 50 Urbana-- Bowditch, R. P. Broderick, E. L. Compton, W. E. Cunningham, J. S. Fahnestock, M. K. Faulkner, G. Gallagher, P. Konzo, S. - Kratz, A. P. Severas, W. H. Willard. A. C. Wright, W. J. Villa Park-- Armspach, O. W. Wilmette-- Norris, W. D. Winnetka-- Ellis, E. E. Zion-- Baughman, L. R. INDIANA Evansville-- Bulleit, C. R. Huntington-- Smith, G. W. Indianapolis-- Ammerman, C. R. Fenstermaker, S. E. . Hagedon, C. H. Hayes, J.'G. . Kruse, R. W. Ott, R. C. Poehner, R. E. Supple, G. B. Warren, C. N. Lafayette-- Hoffman, J. D. LaPorte-- Shrock. J. H. Michigan City-- Stockwell, W. R. Peru-- Pyle, J. W. Thrush, H. A. St. Mary-of-tbeWoods Bisch, B. J. Wabash-- Shivers, P. F. IOWA Ackley-- Nelson, G. O. Adel-- . Shaw, B. E. Cedar Falls-- Clay. C. H. Cedar Rapids-- Pappenfus, W. G. Council Bluffs-- Huffacker, H. B. LeMars-- Mathey. N. J. Roll of Membership Sioux City-- Hagan, W. V. Waterloo-- Winterbottom, R. F. KANSAS Hutchinson-- Mann, A. R. Stevens. H. L. Lawrence-- Machin, D. W. Sluss, A. H. Sallna-- Ryan, W. F. KENTUCKY Cold Spring-- Ward, F. J. Ft. Thomas-- Reik. R. C. Stevens, W. R. Lexington-- May, J. W. O'Bannon, L. S. Louisville-- Hellstrom, J. Murphy, H. C. Reed, W. M. LOUISIANA Choudrant-- Rinehart, W. R. New Orleans-- Gamble, C. B. Gammili, O. E., Jr. May. G. E. McLaren, F. S. Moore, H. W. Ryan, J. D. Shreveport-- Fitzgerald, W. E. MAINE Auburn-- Fowles, H. H. " Portland-- Fels, A. B. Merrill, C. J. Swanson, H. MARYLAND Baltimore-- Axeman, J. E. Collier, W. I. Hail, M. S. Lednum, J. M. Leilich, R. L. McCormack, D. Posey, J. Seiter, J. E. Shepard, J. deB. Smoot, T. H. Steele, M. G. Vance, L. G.. Vincent, P. J. Whiteley. S. M. Brooklyn Park-- Rodgers, J. S. EUlcott City-- Tibbets, J. C. East Springfield-- Wolfert, E. R. Rockville-- Brunett, A. L. Roland Park-- Dorsey, F. C. Fitchburg-- Earley, T. J. Illig, W. R. Karlson, A. F. McKittrick, P. A. Silver Spring-- Fineran, E. V. Stack. A. E. Harwich Port-- Maxwell. G. W. MASSACHUSETTS Arlington-- Shaw, N. J. H. Arlington Heights- Tarr, H. M. Boston-- Archer, D. M. Berchtold, E. W. Boyden, D. S. Brinton, J. W. Brissette, L. A. Bryant, A. G. Bullock, T. A. Cummings, C. H. Donohoe, J. B. Drinker, P. Dusossoit, E. A. Edwards, D. J. Foulds, P. A. L. Franklin, R. S. Gerrish, G. B. Gleason, G. H. Hajek, W. J. Hilliard, C. E. Hoyt, C. W. Keefe. E. T. Kelley, J. J. Kellogg, A. Kimball, C. W. McCoy. T. F. Merrill, F. A. Miller. J. F. G. Moulton, D. Osborne, M. M. Palmer, R. T. Rydell, C. A. Shaw, E. Stetson, L. R. . Swaney, C. R. Turner, J. Tuttle. J. F. . Waterman, J. H.1 Yaglou, C. P. Brookline-- Riley. E. C. Cambridge-- . Baker, R. H. ` Flint. C. T. Haddock, I. T. Holt. J. W. MacDonald, E. A. Moore, H. C. Cochituate-- Abeam, W. J. Dalton-- Dakin, H. W. E. Dedham-- Higgins, T. J. Dorchester-- Brown, M. . Goodrich, C. F. Hosterman, C. O. Plunkett. J. H. Shaer, I. E. Holyoke-- Colby, C. W. Hyde Park-- Bartlett, A. C. Ellis, F. R. Epple, A. B. Fritzberg, L. H. Keyes, R. E. Wolf, J. C. Lawrence-- Bride, W. T. Leominster-- Kern, R. T. Lexington-- ' Brigham, F. H. Lynn-- Feehan, J. B. Oates, W. A. Malden-- Ahlberg, H. B. Medford-- Cushman, L. D. Melrose-- Cole, E. Q. Dodge, H. G. Milton--. Mitchell. C. H. Needham-- Park, C. D. Webb. J. S. Newton Center-- Murray, J. J. Newtonvllle-- Emerson, R. R. McMurrer, L. J. Quincy-- Stone, E. R. Reading-- Ingalls, F. D. B.. Revere-- Foulds. S. T. N. Springfield-- Cross, R. E. Holmes, R. E. Leland, W. B. McDowell, B. W. Murphy, W. W.. O'Neil, J. M. Swampscott-- Knowles, M. G. Waban-- . Jones, W. T. 51 Watertown-- Wicgner, H. B. Wellesley Hills-- Barnes. W. E. Gilling, W. F., Jr. West Roxbury-- Christie, A. Y. McPherson, W. A. Walsh, E. R., Jr. Weymouth-- Clough, L. ^ Winchester-- Jackson, A. B. Woburn-- Parker. P. Wollaston-- Hodgdon, H. A. Worcester-- Robinson, H. C. Turner, P. K. Wechsberg, O. MICHIGAN Ann Arbor-- Backus. T. H. L. Eckert, E. K. Marin, A. Battle Creek-- Christenson, H. Birmingham-- Hadjisky, J. N. Detroit-- Akers, G. W. Amoldy, W. F. Baker, I. C. Baldwin. W. H. Barth, H. E. Bishop, F. R. Blackmore, F. H. Boales, W. G. Booth, H. N. Brennan, J. W. Burks, R. H. Chappell, H. D. Chester, T. Connell, R. F. Conrad, R. Coon, T. E. Cooper, F. D. Cummins, G. H. Darlington. A. P. Dauch, E. O. DeBoos, F. A. Dubry, E. E. Eggleston, L. W. Feely, F. J. Fitzgerald, J. Giguere, G. H. Glanz, E. Hamlin, H. A. Harms, W. T. Harrigan, E. M. Heydon, C. G. Hogan, E. L. Hutzel, H. F. Kilner, J. S. Kirkpatrick, A. H. Knibb, A. E. Linsenmeyer, F. J. Luty, D. J. Maier, G. M. McColl, J. R. American Society of Heating and Ventilating Engineers Guide, 1936 McConachie, L. L. Mclntire, J. F. McLean, D. Miller, R. E. Milward, R. K. Morse, C. T. . O'Gorraan, J. S., Jr. Paetz, H. E. Parrott, L. G. Partlan, J. W. Pike. W. H. . Purcell. F. C. Purcell, R. E. Randall, W. C. Rickner. C. A. Rowe, W. A. Sanford, S. S. Sauer, R. L. Schechter, J. P. . Shea, M. B. Snell, E. J Snyder, J; W. , Spitzley, R. L. Spurgeon, J. H. ' Taylor, W. E. : - Toonder, C. L. - Turner, J. W. Tuttle, G. H. Walker, J. H. . Wallace. J. B. Wallich, A. C. Wigle, B. M. Winans, G. D. Wood. F. C. Dowaftlac-r- Firestone, J. F. Torr, T. W. E. Lansing-- Miller, L. G. Flint-- Smith, 1C. M. Grand Rapids-- Bradfield, W. W. Morton, C. H. Taze, D. L. Todd, S. W.. Jr. . Troske, J. J. Wierenga, P. O. Ziesse, K. L. Hibblng-- Miller. L. L. . Holland-- Bemstrom, B. Cherven, V. W. . Van Alsburg, J. H. Houghton-- Seeber, R. R. ; Kalamazoo-- . Brinker, H. A. Downs, S. H. . McConner, C. R. Schlichting, W. G.. Temple, W. J. Wilson, R. W. Lansing-- .. Adams, E. I.. Chrouch, R. B. Distel, F. Haas, R. B. McLouth, B. F. Parsons, R. A. . Vanderlip, P. J. Muskegon Heights-- Reid. H. F. . Port Huron-- .Blessed, W. A. St. Joseph-- Milliken, V. D. MINNESOTA Bayport-- Swanson, E. C. Cloquet-- Spafford, A. Duluth-- Foster, C- . International Falls Nelson, R. A. . . Minneapolis-- Aiken, J. F. Algren, A. B. . Anderson, S. H. Armstrong, R. W. Bean, G. S. Bell, E. F. Bensen, C. L. Betts, H. M. Bjerken, M. H. Bredesen, B. P. Buot, A. V. Burns, E. J. Burritt, C. G. Butts, R. L. Cash, T. T. Copperud, E. R. Dahlstrom, G. A. Dovolis, N. J. Edelman, B. P. Fergestad^ M. L. Forfar, D. M. oemsn, n. c,. . Gordon, E. B., Jr. Gordon, W. J., Jr. Gross. L. C. Haatvedt, S. R. Hall, J. R. Hamerski, F. D. Hanson, L. P. Harris, J. B. ' ' Hildebrandt, H. A. Hitchcock, P. C. Howard,. E. Huch, A. J. Johnson, L. H. Jordan, L. E. . Jordan, R. C. . King, R. L. ` Kingsland, G. D. Knudtson, C. M. Kuehn, W. C. Kuns, J. W. Lange, F. F. ' Legler, F. W. Leslie, D. E. Lund, C. E. - Magney, G. R.. Martenis, J.V. Maynard, H. R. Miller, H. A. Mills, H. C. ' . Mjolsnes, L. O. Morgan, G. C. Morton, H. S. Myers, C. R. Ostrin, A. ' Pfeifer, O. J., Jr. Powell, K. A. Pung, D. W. Roberts, J. R. . Rossiter, P. A. Rowley, F. B.' Sanford, A. L. Schembeck, F. H. Seelert, E. H. Seepe, P. E. . Spencer, J. B. Stiller, F. W. Sundell, S. S. Sutherland, D. L. Swanson, R. G. Sweiven, C. E. Swenson, J. E. Tabor, C. B Uhl, E. J. . Uhl, W. F. Van Horn, H. T. Welter, M. A. Whallon, F. Wiggins, O. J. Willis. L. L. Owatonna-- Clarkson, W. B. Robbinsdale-- Sweatt, C. H. Rochester-- Adams, N. D. Shevlln-- Nesdahl, E. . St. Paul-- . Anderson, D. B. Ayers, E. H. Backstrom, R, E. Barnum, C. R. Bauer, A. E. Buenger, A. Collins, M. D. ` Fitts, C. D. Gausman; C. E. Gill. J. W. .. Haslett, H. M. Hickey, D. W.: Hyde, L. L. Jones, E. F. McNamara, W. Oberg, H. C. Pennel, R. ' Poucher, R. C. Ruff, D. C. Swanstrom, A. E.;. Winterer, F. C. Wunderlich, M. S. Wayzata-- Heberling, C. W. MISSOURI Clayton-- DuBois, L. J. Ferguson-- - Szombathy, L. R. Jefferson City-- Woodman, L. E. Kansas City-- Adams, C. W. Allan, N. J. Arthur, J. M.. Betz, H. D. Bliss, G. L. Buckley, M. B. Caleb. D. Campbell, E. K. Campbell,. E. K., Jr. 52 Cassell, W. L. Chase, L. R. Clegg. C. Cook, B. F. Dawson, T. L. Dean, F. J., Jr. Disney, M. A. Dodds, F. F. Downes, N. W. Eppright, J. O. Fehlig, J. B. Filkins, H. L. Flarsheim, C. A. Gillham, W. E. Haas, E., Jr. Kell, W. R. Kitchen, J. H. Lewis, J. G. Maillard, A. L. Matthews, J. E. Millis, L. W. Natkin, B. Nottberg, G. Nottberg, H. . Olchoff, M. Olson, G. E. Pines, S. Rivard, M. M. Rudio, H. M. Russell, W. A.- Sawyer, J. N. Sheppard, F..A. Stephenson, L. A. Weiss, C. A. = Zink, D. D. . Maplewood-- Walters, A. L. St. Joseph-- Harton, A. J. St. Louis-- Barry, J. G., Jr. Bayse, H. V. Bradley, E. P. Carlson, E. E. . Cooper, J. W. . Corrigan, J. A. Davis, C. R. Edwards, D. F. Fagin, D. J. Fillo, F. B. . Foster, J. M. / Gilmore, L. A. Grossmann. H. A. - Hamig, L. L. Hamilton. J. E. - Hartwein, C. E. Hester, T. J. Hugoniot, V.' E. Kent, J. K. Langenberg, E. B. Manahan, J. E. McLamey, H. W. McMahon, T. W. Moon, L. W. O'Brien, W. N. . Reed, P. L. Rodenheiser, G. B. Rosebrough, R. M. Sodemann, P.. W. Sodemann,. W. C; B. Stammer, E. L. Tenkonohy, R. J. White, E. A. Sedalia-- ' Middleton, H. A. University City-- Falvey, J. D. Webster Groves-- Myers, G. W. F. Ranck, G. L. Roll of Membership MONTANA Big Timber-- Strickland, A. W. Billings-- Cohagen, C. C. Bozeman-- Powers, F. I. Great Falls-- Ginn, T. M. NEBRASKA Clarks-- ' Manning, W. M. Omaha-- Lindberg, A. F. NEW HAMPSHIRE Holderness-- Meakin, J. B. NEW JERSEY Arlington--> Adler, A. A. Bock, B. A. Asbury Park-- Strevell, R. P. Atlantic City-- Strouse, S. B. - Bayonne-- Schwartz, J. . . Belmar-- Merkel, F. P. Bloomfield-- Clericuzio, G. P. Faust, F. H. Harrington, E. Hochuli, H. W. . Lyon, P. S. McLepegan, D. W. Tenney, D... . Camden-- Brown, W. M. Coward, C. W. Kappel, G. W. AV Lanning, E. K. Rohlin, K. W. Webster, E. K. . Webster, W. Webster, W., Jr. Collingswood-- Mohrfeld, H. H. Plum. L. H. Cranford-- * Roos, E. B. J. East Orange-- Ferguson, R. R. Gombers,.H. B. Grahn, V. F. Rack, E. C. Reilly. J. H. Tallmadge, W. Turno, W. G. W. Elizabeth--: Atkinson, K. B. Cornwall, G. T. Grant, W. A. Merle, A. Wheller, H. S. ` Perth Amboy-- Simian, M. Plainfield-- Hedges, H. B. Tobin, G. J. Essex Fells-- . Stacey, A. E., Jr. Ridgefield Park-- Davis, A. C. Grantwood-- Butler, P. D. Ridgewood-- Fitts, J. C. Had donfield-- Dobbs, C. E. Jones, R. E. . Hasbro uck Heights-- Goodwin, S. L. Hawthorne-- - Lawton, F. C. Spoelstra, W. J. Irvington-- Reinke, A. G. Stengel, F. J. Jersey City-- . Hashagen, J. B. Jones, H. L. Kelly, C. J. Ritchie, W. , Walterthum, J. J. ' Lyndhurst-- Ehrlich, M. W. . Maplewood-- Kepler, D. A. . Kylberg, V. C. . ` Smith, M. S. Merchantvllle-- Binder, C. G. Montclair-- Bentz, H. Newark-- . Alt, H. L. Ashley, C. M. . Bryant. P. J. : Carey. P. C. . Carrier, W. H. Connell, H. Day. V. S. French, D. Holbrook, F. M. Holton, J. H. Ingels, M. Leinroth, J. P. Lewis, L. L. Lewis, T. Lyle, J. I. Lyman, S. E. . Morehouse, H. P. Rachal, J. M. Ray, L. B. Raymer, W. F., Jr. Rice. R. B. Soule, L. C. Steinmetz, C. W. A. Tavanlar, E. J. West, P. North Arlington--- Bermel, A. H. Vogelbach, O. Orange-- Crawford, J. H., Jr. Paterson-- Bannon, L. E. Cox. H. F. Pryor, F. L. River Edge-- Mawby, P. Rochelle Park Emery, G. W. Roselle Park-- Kampish, N. S. South Orange-- Browne, A. L. . Hansen, C. C. Summit-- Oaks. O. O. Teaneck-- Heebner, W. M. Union City-- Taverna, F. F. Verona-- Shotwell, R. W. Stone, G. F. Westfield-- Scribner, E. D. West Orange-- Adlam, T. N. West New York-- Stinard, R. L. NEW YORK ; Albany--. Bond, H. A. Dick. A. V. Johnson, H. S. Murray, T. F. Ryan. H. J. Taggart, R. C. Binghamton-- : Brown, R. F. Marum, O. ... Bronxville-- 1 Dornheim, G. A. Livar, A. P. Buffalo--' Beman, M. C. Booth, C. A. Cherry, L. A. Cheyney, C. C. Cressy, R. E. Criqui, A. A. . ` . Currier, C. H. Danforth, N. L. Davis, J. Day, H. C. Dyer, O. K. Erdle, G. F. E^schenbach, S. P. Evans, C. A. Farnham, R. Farrar, C. W. . Gifford, C. A. Hamlin, C. J., Jr. 53 Harding. L. A. Heath, W. R. Hedley, P. S. Hexamer, H. D. Hirschman, W. F. Jackson, M. S. Johnson, E. E: Kaiser, F. Kamman, A. R. Landers, J. J. Lighthart, C. H. Lov^ C. H. Madison, R. D. Mahoney, D. J. McGaughey, J. E., Jr. McKinley, C. B.` McTernan, F. J. Mosher, C. H;. Rente, H. W. Roebuck, W., Jr.. Seelbach, H. Shelney, T. Snyder, J. S. Strouse, S. W. Thornton, R. T. Voisinet, W. E. Walker, E. R. Wendt, E. F. Yager, J. J. ' Clarksville-- Teelirig, G. A. Derby-- Ensign, W. A.. Elmira-- Davis, B. C. . . Geneva--- Herendeen, F. W. Hamburg--- Graham, C. H. Hastings-onHudson-- Reynolds, T. W. Hudson Falls-- . Hollister, E. W. Irvington-on- Hudson-- . Bastedo, A. E. Ithaca-- Barns, A. A. Sawdon, W. M. Williams, J. W. Woods, Ei H. Jamestown-- Sharp, F. H. . Kendall-- Stangland, B. F. Kenmore--. Candee, B. C. Quigley, W. J. Larchmont--: Downe, E. R. Gaylor. W. S. Lockport^- Bishop. C. R. Saunders, L. P. Mt. Vernon-- Freitag, F. G. . Northoh, L. Obert, C. W. of and 1936American Society Heating Ventilating Engineers Guide, New Rochelle-- Abrams, A. Farley, W. F. Giannini, M. C. Rose. H. J. New York City-- Addams, H. Ames, C. F. . Ashley, E. E. Atherton. G. R. Bachler, L. J. Baker, H. L., Jr, Balsam, C. P. (Brooklyn) Barbera, H. A. Barbieri, P. J, ! Bamum, M. C. Baum, A. L. Beebe, F. E. W. ' Bennett, E. A. Bennitt, G. E. Berman, L. K. Bernhard, G. (Brooklyn) Bilyeu, W. F. Blackburn. E. C., Jr. (Hempstead, L. I.) Blackman, A, O. Blackmore, J. J.. Blackshaw, J. L. (Brooklyn) Bloom, L. (Brooklyn) Boainger, J. H. . Bolton, R. P. Bowles, P. Brabbet, C. W. Broome, J. H. (Brooklyn) Buensod, A. C. Bulkeley, C. A. Burbaum, W. A. Buttaravoli, F. ' (Brooklyn) Callaghan, P. F., Jr. (Brooklyn) Callahan, P. J. (Great Kills, S. I.) Campbell, F. B. Campbell, R. E. (Coney Island) Carpenter, R. H. Charles. T. J. Charlet, L. W. Chase, C. L. (Brooklyn) Crone, T. E. Cucci. V. J. Dailey, J. A. (Astoria, L. I.) Daly, R. E. Darts. J. A. Davison, R. L. DeBlois. L. A. Deely. J. J. (Brooklyn) ' Denise, J. R. Denny, H. R. . Dodge, H. A. Donnelly, R. Driscoll, W. H. Duff. K. Durkee, M. E. Dwyer, T. F. (Brooklyn) Eadie, J. G. Eells. H. B. - (Brooklyn) . Elliott, L. Engle, A. Everetts, J,, 'Jr. , Faile. E. H. Fansler, P. E. Farbman, L. X. Fay, F. C. Feldman, A. M. Fenner, N. Pi Fiedler. H. W. Finch, S. B. (Brooklyn) Fleisher, W. L. Flink, C. H. Frank, O. E. Frey, G. O. Friedman. M. Fritz, C. V. (Freeport) Galloway, J. F. (Brooklyn) Gilmour, A. B. (Brooklyn) Glore, E. F. Goldberg, M. (Brooklyn) Gordon. P. B. Gornston, M. H. (Brooklyn) Goulding, W. (Brooklyn) Green, A. W. (Jackson Heights., L. I.) Greenburg, L. Groves, S. A. (Forest Hills) Hament, L. Hartman. F. S. Hateau, W. M. Heibel, W. E. Henry, A. S., Jr. Hering, A. Herkimer, H. Herske, A. R. Herty. F. B. (Brooklyn) Hicks. H. K. Hiers, C. R. (Great Neck, L. I.) Hildreth, L. W. Hinkle, E. C. (Hempstead, L. I.) Hinrichsen, A. F. Hoehl, E. R. Hoffman, C. S. Hollister, N. A. (Brooklyn) Hosking, H. L. Hotchkiss, C. H. B. Howell, F. B. Hyman, W. M. Issertell. H. G. Jacobus. D. S. James, J. W. Janet, H. L. Johnson. E. B. QV. New-Brighton. Johnson, W. A. Johnston, W. H. Jordan, W. D. Kastner,. G. C. Keplinger, W. L. Kimball. D. D. Knopf, C. (Brooklyn) Kiihlmann, R. . Lane, D. D. ' (Whitestone, L. I ) Lennon, J. O. Leupold, H. W. (Elmhurst, L. I.) Leventhal, B. Lucke, C. E. Lyle. E. T. Lyons, M. A.' Mandeville, E. W. (Brooklyn) Markush, E. U. Marshall, H. H. 54 Martin, G. W. Matzen, H. B. . (Brooklyn) McClintock, W. McCloughan, C. (Brooklyn) McKiever, W. H. McLeish. W. S. Mehne. C. A. Meinke, H. G. Meisel, C. L. Meyer, C. L. Meyer, H. C., Jr. Miller, C. A. Miller, L. B. Montgomery, O. C. Moore, R. E. (Brooklyn) Morse, F. W. Moss, E. (Brooklyn) Munder, J. F., Jr. Munier, L. L. Munson, J. L. Murphy, C. G. Neale, L. I. Offner, A. J. Olsen, G. E. (Arverne, L. I.) Olson, R. G. Olvany, W. J. Pabst, C. S. Patorno, S. A. S. Perina, A. E. (Port Richmond, S. I.) Pfuhler, J. L. (W. New Brighton, S. I.) Phillips, F. W., Jr. (Brooklyn) Pihlman, A. A. - Pinder, P. H. Place, C. R. Pohle, K. F. Price, E. H. (Riverhead, L. I.) Priester, G. B. Purdy, R. B. Purinton, D. J. Quirk. C. H. Raisler, R. K. Raynis, T. (Woodhaven L. I.) Reynolds, W. V. Richardson, H. T. dm... r* I (Jamaica, L. I.) Ritchie, E. J. Ritter, A. Rodman, R. W. Rosenberg, P. Rosenburg, W. E. (Locust Valley, L. I.) Ross, J. O. Roth. C. F. Ruppert, E. H. Sanbera, E. N. Sawhill, R. V. Schneider, W. G. Schoepflin, P. H. Schulze, B. H. Scott. C. E. Scott, G. M. - Seelig, A. E. Sellman, N. T. Senior, R. L. Seward, P. H. (Brooklyn) Shepard, E. C. Siebs. C. T. Siegel. L. (Brooklyn) Simpson, A. M. Skidmore, J. G. (Long Island City) Sklenarik, L. Staples, W. H. Steeneck, K. C. (Bellaire, L. I.) Sternberg, E. Sterne, C. M. (Long Island City) ' Stewart, C. W. SU11, F. R. Stitt, A. B. Strock, C. Strunin, J. Sutton, F. (Babylon, L. I.) Syska, A. G. Thomson, T. N. (HunUngton, L. I.) Tiltz, B. E. Timmis, W. W. Tisnower, W. (Brooklyn) Torrance, H. Tucker, F. N. (Freeport, L. I.) Tusch, W. (Brooklyn) Tyler, R. D. Vetlesen, G. U. Vivarttas, E. A. (Brooklyn) Vogt, J. H. Wachs, L. J. (Brooklyn) Waechter, H. P. (Thompkinsville, S. I.) Wagner, F. H., Jr. Walker. W. K. Wallace, G. J. (Elmhurst, L. I.) Wallace. W. M., II (Hollis. L. I.) Walton, C. W.. Jr. Waring, J. M. S. White, E. S. Whitelaw, H. L. Whittaker, W. K. (Flushing, L. I.) Wilder. E. L. WUson. H. A.. Jr. Winquist, W. J. (Brooklyn) Wohl, M. W. , (Brooklyn) ' Wolf. P. Worsham, H. North Tonawanda-- Conaty, B. M. Ortskany-- Oakey, W. E. Ossining-- Hooper, V. F. / Patchoque-- Blakeslee, D. Jalonack, I. G.' Pelham Manor-- Peacock, J. K. Rochester-- Betlem, H. T. Coe. R. T. Cook, R: P. Hakes, L. M. Hutchins, W. H. . Sheldon; N. E. ' Stacy, S. C. Vidale, R. Welsh, H. S. Roll of Membership Rome-- Lynch, W. L. Scarsdale-- Cumming, R. W. Ullman, H. G. Schenectady-- Hunziker, C. E. Seely, I. R. . Vogel, A. Welch, L. A,, Jr. Snyder-- John, V. P. Syracuse-- Acheson, A. R. Woese, C. F. Tarrytown-- Weiss, A. P. Tonawanda-- Karlsteen, G. H. Utica-- Steinhorst, T. F. White Plains--` Johnson, L. O. Rose, A. A. Zibold, C. E. Willlamsville-- Rente. S. R. Yonkers-- Bense, W. M. Goerg, B. Harmonay, W. L. Hayter, B. Hopp, H. K. Kelly, J. G. Rainger, W. F. Zuhlke, W. R. NORTH CAROLINA Charlotte-- ' Brandt, E. H. Hodge, W. B. Mozley, R. G. Small, B. R. High Point-- Gray. W. E. Winston-Salem-- Bahnson, F. F. Cornwall, C. C. Page. A. Rueger, C. A,, Jr; NORTH DAKOTA Grand Forks-- Pesterfield, C. H, OHIO BeHefontaine-- Quay, D. M. Berea-- Curtis, H. F. Clnrinup tl-- Bird, C. Breneman, R. B. Coombe, J. Doyle. W. J. Floyd, M. Grabensteder, L. Green, W. C. Helburn, I. B. Houlis, L. D. Houliston, G. B. Hust. C. E. Kiefer. C. J. KitcheU, H. N. Kramig, R. E., Jr. Little, K. B. Pillen, H. A. Pistler. W. C. Powers, L. G. Richard, E. J. Royer, E. B. Schick, K. W. Sigmund, R. W. Smith, J. A. Sproult, H. E. Washburn, M. J. Winther, A. > Wright, K. A. Cleveland-- Allmen, N. S. Andes, W. Avery, L. T. Bailey. E. P.. Jr. Brooks, F. W. . Brueggeman, A. R. Cary, E. B. Cohen, P. Conner, R. M. Davis, J. R. Dickenson, F. R. Eveleth, C. F. Fonda, B. P. Geissbuhler, J. O. Gottwald, C. Graham, W. D. Harvey, L. C. Kalinsky, A. G. Kartorie, V. T. Kitchen, F. A. Klie, W. . Levy, M. I. . Martinka. P. D. Miles. J. C. Moeller, R. Pogalies, L. H. Rather, M. F. Repko. J. J. Schmidt, R. H. ' Smith, W. D. Tuve, G. L. Vanderhoof, A. L. Wetzell. H. E. Wilhelm. J. E. . Young, E. O. Cleveland Heights-- Davis, R. G. Rodgers, F. A. Columbus-- Brown, A. 1. Sherman, R. A. Smith, R. H. Wheeler, O. J. Williams, A. W. Cuyahoga Falls-- . Humphrey.. D. E. Read, R. R. Dayton-- _ Gibbons, M. J. Hill. H. H. Hull, H. B. LaSalvia, J. J. Lewis, C. E. MacMillan, A. R. Smith, L. E. Stevenson, M. J.Swift, P. F. Williams. F. H. East Cleveland-- Morris, F. H. Nobis, H. M. Sennet, L. E. Stark. W. E. Steffner, E. F. Elyria-- Maynard, J. E. Lakewood-- Longcoy, G. B. Vermere, E. J. Lockland-- Ruff, A. G. Mansfield-- Blair, H. A. Newark-- Simpson. D. C. Slayter, G. . Norwood-- Braun, J. J. Motz, O. W. Painesville-- . Hobbs. J. C. Rocky River-- Webb, E. C. Toledo-- Baker, H. C. Bichowsky, F. R. Myers, F. L. Treadway, Q. York-- Schurman, J. A., Jr, Youngstown-- Boucherie, H. N. Choffin, C. C. OKLAHOMA Norman-- Bowman, J..W, Cook, A. B. Dawson. E. F. Frampton, A. C. Giles, J. C. Husky, S. T. Rauh, E. M. Sneed, R. B. Sonney, K. J. Oklahoma City-- Beard, E. L. . Constant, E. S. Dolan, R. G. Dugger, E. R. Emmons, N. L. Gray, E. W. Hoppe, A. A. Howlett, 1. G. Leverance, H. J. Loeffier, F. X... Loeffler, L., Jr. Miller. B. R. Miner, M. H. Rathbun. P. W. Rolland, S. L. Tauson, P. O. Tiller, L. Tulsa-- Holmes', A. D. Jones, Et . 55 OREGON Corvallis-- Willey. E. C. PENNSYLVANIA Allentown-- Korn, C. B. Ardmore-- Haynes, C. V. Ardsley-- Tucker, L. A. Atglen-- Thompson, E. F. Beaver Falls-- Van Alen. W. T. Beechwood, Del. Co.Kipe, J. M. Bethlehem-- Stuart, M. C. Blalrsvllle-- Stitt, E. W. Bradford-- Black, W. B. Brookline-- Eastman, C. B. Chambersburg-- Kottcamp, H. A. Cheltenham--. McEIgjn, J. W. Cynwyd-- Smith. W. F. Whitney,' C. W. Easton-- Livingston, B. B. E. Pittsburgh-- Goodwin, W. C. Elizabethtown-- Dibble, S. E. Erie-- Joyce. H. B. Folcroft-- Williams, C. R. Germantown-- Mack, L; Marks, A. A. Harrisburg-- Eicher, H..C. Geiger, I. H. Lutz. J. H., Jr. ' Haverford-- Black. E. N.. 3rd Jenklntown-- Slight, I. ' Johnstown-- Novotney, T. A. Kingston-- MacDonald, D. B. American Society of Heating and Ventilating Engineers Guide, 1936 Lancaster-- Tones, A. Lloyd, E. C Long, D. R. Lansdowne-- Hance. W. W. James, H. R. Manheim-- Weitzel, P. H. Marysville-- Gault. G. W. McKeesport-- Dugan, T. M. Meadville-- Williams, L. E. Merlon-- Atkins, T. J. Middletown-- Locke, R. A. Narberth-- Henszey, W.P. New Castle-- Andrews, G. H. Sonnebom, C. New Kensington--. Osterle, W. H. Norristown-- . Bolsinger, R. C. Hucker, J. H. Philadelphia-- Adams.B. Bartlett, C. E. Black, H. G. Blankin, M. F. Bogaty, H. S. Bornemann. W. A. Braemer, W. G.R. Breitenbach, G. C. Burke. J. J. Caldwell, A. C. Cassell, J. D. Clarkson, R. C., Jr. Clodfelter, J. L. Cornell, J. C. Culbert, W. P. Dambly, A. E. ; Davidson, L/C. Davidson, P. L. . Dever, H. F. Donovan, W. J. ' C>U1UI| Cl. . Engel, E. - Erickson, H. H. . Faltenbacher, H. J. Familetti, A. R. Galligan, A. B. Gant, H. P. . . Gemmill, R. A`. Gillett, M. C. . Gilman, F. W.- Glassey, J. W. Hackett, H. B. Hibbs, F. C. Hires, J. E; . Hoft, P. J. Hunger, R. F. Hynes, L. P. . , Ickeringill, J. Cl Kelble. F. R. Kriebel, A. E. ... Leopold, C. S: ' Lewis, G. C. ... MacDade, A. H. .. Mann, L; B. * Martocello, J. A. - Mather, H. H. McClintock, A., Jr. Mellon, J. T. J. Mensing, F. D. Meyer, J. W. Monday, C. E. Moody, L. E. Morgan, R. C.- Morris, A. M. Naylor, C. L. Nesbitt, A. J. Nesbitt, J. J. Newcomb, L. B. Nusbaum, L. . Plewes, S. E. Powers, E. C. Pryibil, P. L. Redstone, A. L. Reilly, C. E. Rettew, H. F. Rhea, C. A. Roberts, H. L. ' Rugart, K. Sabin, E. R. Shanklin, A. P. Sheffler, M. Speckman, C. H. - Stevens, J. M. Thornburg, H. A. Timmis, P. Touton, R. D. Traugott, M. Trump, C. C. . Tuckerman, G. E. Walsh, J. A. Wandless, F. W. Wegmann, A. Wilmot, C. S. Wiitberger, C. F. Woolston, A. H. Pittsburgh-- : Aston, J. Beighel, H. A. ' Blackmore, G. C. - * Brauer, R. . Burns, R. Bushnell, C. D. Carr, M. L. Cheeseman, E. W. Collins, J. F. S., Jr. Comstock, G. M. Dorfan, M. I. Edwards, P. A. Ellis, G. P. Evans, E. C. . Farbman, S. M. Frisse, J. L. Giles, A. F. Goodman, D. . Greiner, G. E., Jr.; Gunther, F. A. Hecht, F. H. , Heilman, R. H. . Houghten, F. C. , Humphreys, C. M. Huettner. H. F. ; Kellner, D. C. ; Kennedy, O. A. ", Kennedy, P. V. ' Maehling, L; S. ' ' Maginn, P.' F: , McGinness, J. E.' ; McGonagle, A. ` McGuigan, L. A. ' McIntosh, F. C.' . McMunn, A. H.' Miller, R. A. . . Moore; H. L.` / Nass, A. F. ' . / . Neis, W. A. ' : Nicholls, P. .. . Noord, D. F. O'Neill. P.; . Pittock, L. B/' Reed. I. G. Reed, V. A. Richmond, J. Riesmeyer, E. H., Jr. Rockwell, T. F. Rodgers, W. C. Scanlon, E. S. Smyers, E. C. Speller, F. N. Stanger, R. B. Steen, J. M. Steggalt, H. B. Stevenson, W. W. Strauch, P. C. Tennant, R. J. J. Tower, E. S. Waters, G. G. Yates, G. L. Zangrilli, A. J. Pottsville-- . Marty, E. 0 Smith, J. D. Primos, Del. Co.-- Johnson, A. J. Prospect Park--. Robinson, G. L. Reading-- Luck, A. W. Nicely, J. E. Ridley Park-- Stalb, J. G. Rutledge-- Jones, N. R. Vroome, A. E. Scranton-- Mahon, B. B. Shaver, H. H. Springfield-- Grossman, H. E. Payne, R. E. . State College-- Queer. E. R. Stroudsburg--1 . Kiefer, E. J., Jr. Tamaqua-- Hadesty.'A. L., Jr. Koch. H. O. Tarentum-- . Burkhart, E. M; Upper Darby-- . . Aughenbaugh. HI E. Blackmore, j; S. Bonthron.-R. C. ' Currie, F. J. .. . ; Taliaferro; R. R- Villanova-- Barr. G. W. Carey, J; A. Wallingford-- Arnold, R. S. . . .. Wilkes-Barre-- Santee, H. C. . Wilkin8burg-- Campbell, T. F. Wormleysburg-- Miller, T. G. ; York-- Chapin, H. G/Hertzler, J. R. Zieber, W. E, i 56 PHILLIPINB ISLANDS Manila-- ' Hausman, L. M. Macrae, R. B. RHODE ISLAND Providence-- Coleman, J. B. Gibbs, E. W. Hartwell, J. C. McLaughlin, J. D. Moulder. A. W, SOUTH CAROLINA Clemson College-- Shenk. D. H. Columbia-- Hartin, W. R., Jr. SOUTH DAKOTA Lead-- Pullen, R. R. TENNESSEE Memphis-- Campbell, A. Q., Jr. DTmor, E. J. HoshaU, R. H. Perkins, R. C. Nashville-- Brown, F. Jarratt, P. R. ' . TEXAS Amarillo-- Burnett, E. S. College Station-- Badgett, W. H. Barton, D. H. Giesecke, F. E. Long, W. E. ' Smith, E. G. Teal.E. T. Dallas-- ' Bock, I. I. , Borucb, E. R. Duming, E. H. Gay, L. M. Kribs, C. L., Jr., Landauer, L. L.! Lauterbach, H., Jr. Lynn, J..H. . . Meffert, G. H. Stringfellow, J. C. Taylor, R. F. Weatherby, E. P., Jr. Wilson, J. W. .. . Witmer, C. N.' ' Ft. Worth-- ' Hughes, F., Jr. Skinner, H. W. . ' Galveston-- ' Warren, C.- W.;. ' Hereford-^- . ' Jones, A. P. ' ' Roll of Membership Houston-- . Cochran, W. B. . Groseciose, J. B. Kiesling, J. A. ` Renouf, E. P. ` Spencer, R. M. Irving-- Moler, W. H. Kingsville-- Richtmann, W. M. Lockart-- ` Schucany; O. W. Pyote-- Chestnutt, N. P. San Antonio-- Cotter, R. P. Diver, M. L. Ebert, W. A. Monier, K. A. J,, UTAH Salt Lake City-- Richardson, H. G. VERMONT Burlington-- Lanou, J. E. Raine, J. J. North Ferrisburg-- Breckenridge, L. P. VIRGINIA Danville-- Farley, W. S. East Falls Church-- Casey, H. F. Lynchburg-- Doering, F. L. Wiley, E. C. Norfplk-- Nowitzky, _H. S. Webster, W. H., Jr. Portsmouth-- Stubbs, W. C. . Richmond-- Carle. W. E. Hankins, R. P. Johnston, J. A. Pelouze, H. L., 2nd Schulz, H. I. Snyder, A. K. Rosslyn-- Marshall, W. D. University-- Peebles, J. K., Jr. WASHINGTON Kent-- Boyker, R. O. . Pullman-- O'Connell, P. M. Seattle-- . Beggs, W. E. Bouillon, L. Cook. H. A. Cox, W. W. Daly, C. P. Dudley, W. L. Eastwood, E. O. Forsyth, A. T. Granston, R. O. Griffin, D. C. Hauan, M. J. MacLeod, K. F. Mallis, W. May, C. W. Musgrave, M. N. Peterson, S. D. Pollard,1 A. L. . Twist, C. F. Zokelt, C. G. Tacoma-- Spofforth, W. Yakima-- -' McCune, B. V. WEST VIRGINIA Charleston-- Shanklin, J. A. Shaw, H. W. Thompson, D. Titus, M. S. Wright, M. B. Fairmont-- Wright, C. E. Largent-- Donnelly, J. A. WISCONSIN Beaver Dam-- Schwantes, A. R; Ft. Atkinson-- . Shodron, J. G. Green Bay-- Haus, I. J. Kohler-- Hvoslef, F. W. Kohler, W. J.. Jr. LaCrosse-- Anderegg, R. H. Miller, M. W. Trane,. R. N. . Madison--... . _ . Dean, C. L. . Hess, D. K. Larson, G. L. Nelson, D. W. Plaenert, A. B. White, J. C. Milwaukee-- . Berghoefer, V. A. Bowers, A. F. Bowers, R. C. Brown, W. H. Burch, L. A. Cochran, C. C. Cook, H. R. Elliott, N. B. Ellis, H. W. Hanley, E. V. Haupt. H. F. Hochstein, G. E. Hughey, T. M. . Jackson, C. H. Jepertinger, R. G. Jones, E. A. Jung, J. S. Juttner, O. J. Koch, C. M. Krenz, A. S. Lofte, J. A. Miller, C. W. Miller, H. M. Noll, W. F. ' Page, H. W. Peters; H. H. Randolph, C. H. Rice, C. J. Schnitzer, S. Shawlin, W. C. Spence, M. R. Steinkellner, E. J. Swisher, S. G., Jr. Szekely, E. Trostel, O. A. Volk, J. H. . Wagner, A. M. Weimer, F. G. Wilson, W. H. Neenah-- . Eiss, R. M. . Racine-- . Dixon, A. G.. Menden, P. J. Thomas, N. A. Superior-- Waite, R , West Allis-- Erickson, M. E. Spence, R. T. CANADA - . Brandon, Man.-- Yates. J. E. Brockviile. Oat.-- * Davenport, R, F. Calgary, Alberta-- Clarke, S. S. Walker. A. ' Fort Erie, N. Ont.-- Gordon, W. D. Galt-- Oke,.W. C. Sheldon, W. D., Jr. Halifax, N. S.-- Eagar, R. F. Hamilton, Ont.--. Best, M. W. Maddux, O. L. Islington, Ont.-- Wilson. G. T. Ottawa, Ont.-- Colclough, O. T. Gray, G. A. Pennock, W. B. Preston, Ont.-- . Everest, R. H. Kitchener, Ont.-- Beavers, G. R. Montreal, P. Q*--. Darling, A. B. ' Friedman, F. J. Gameau, L. Givin, A. w. Johnson, C. W. McGrail, T. E. Osborne, G. H. ' Phipps, F. G. Wiggs, G. L. Montreal; W., P. Q.-- Linton, J. P. Regina, Sask.-- . Stewart. J. C. Rigaud, Que.-- Fogarty, O. A. Riverside, Ont.-- Hare, W. A. Three Rivers, Que.-- Germain, O. Toronto, Ont.-- Alexander, S. W. Allsop, R. P. Angus, H. H. Anthes, L. L. Arrowsmith, J. O. 57 Birrell, A. L. Blackhall, L, C. Blackhall. W. R. Boddington, W. P. Church, H. J. Cole. G. E. Dickey, A. J. Duncan. W. A. Eaton, W. G. M. Ellis, F. E. Fitzsimons, J. P. Flanagan, E. T. Fox, E. Fox, J. H. ,, ' Gaby, F. A. Gauley, E. R. Gurney, E. H. Harrington, C. ' Heard. R. G. Henion, H. D. . Hills, A. H. Hopper, G. H. Jeffrey, T. G. Jenney, H. B. . Jennings, S. A. Jone3, A. T. American Society of Heating and Ventilating Engineers Guide, 1936 Kelly, W. C. Lawlor, J. j. Leitch, A. S. Libby, R. S. MacDonald, D. J. MacKenzie, J. J. Marriner, j. M. S. McCrimmon, A. M. McDonald, T. McHenry. R- W. Millar, R. J. Moore. H. S. O'Neill, J. W. Paterson, J. S. Paul, D. I. Philip,'W. Playfair, G. A. Price, D. O. "Purdy, A. K. Ritchie, A. G. Roth, H. R. Shears, M. W. Sheppard, W. G. F. Tasker, C. ' Thomas, M. F. Waldon, C. D, Wardell, A. Watson, M. B. Whittall, E. T. Wood. J. S. Woollard, M. S. Vancouver, B. C.-- Dawson, G. S. Johnston, R. E. Leek, W. McCreery, H. J. Victoria, B. C.-- Sheret, A. Wellington, Ont.-- Johnston, H. D. Winnipeg, Man.-- Aitken, J. Argue, E. J. Eade, H. R. Glass, W. ' Jones, B. G. Kent. R. L. Kirk, C. D. Leonard, J. H. Michie, D. F. Miller, E. R. Munn, E. F. Steele, J. B. Summers, E. T. Thompson, F. Turland, C. H. Watson. H. D. Woodstock, Ont.-- Karges, A. AUSTRALIA Sydney-- . Cherne, R. E. Duncan, J. R. Hunt, N. P. Sands, C. C. BELGIUM Brussels-- Mautsch, R. CHINA Nanking-- Loo, P. Y. Shanghai-- Carter, D. Doughty, C. J. Hart-Baker, H. W. Kwan, I. K. Lofa, N. S. . Merritt, C. J. Morrison, C. B. Waung, T. F. CZECHOSLOVAKIA Prag-- Brust, O. DENMARK Copenhagen-- Reck," W. E. ENGLAND Riifkinghamahlrp-- Russell, J. N. Leeds-- Jennins, H. H. London-- Bailey, W. M. Butt. R. E. W. Greenland, S. F. Haden. G. N. Herring, E. Nobbs, W. W. Middlesex-- Case, W. G. Chipperfield. W. H. Stockport-- Webb. J. W. Sutton-- Casperd, H. W. H. Swinton-- Yates, W. Trowbridge-- Haden, W. N. Westminster-- Faber, Dr, O.. Wolverhampton-- Tyson. W. H. FRANCE Dijon-- Bur, J. R. C. Lille-- Neu, H. J. E. Lyon-- Goenaga, R. C. Paris-- Beaurrienne, A. Downe, H. S. Modiano, R. Nessi, A. Schmutz, J. GERMANY Berlin-- Brandi, O. H. Stuttgart-- Klein. A. INDIA New Delhi-- Heard, J. A. E. IRELAND Cork-- . Barry, P. 1. ITALY Milan-- Donzelli, E. Gini. A. Hauss, C. F. JAPAN Osaka-- Fukui, K. Tokyo-- Kitaura, S. Kozu, T. Saito, S. Sekido> K. MEXICO Mexico, D. F.-- Darby, M. H. Gilfrin, G. F. Martinez, J. J. NEW ZEALAND Christchurch-- Taylor, E. M. Vale. H, A. L. Dunedin-- Davies, G. W. NORWAY Oslo-- Alfeen."N. Tjersland, A. SOUTH AFRICA Johannesburg-- Carrier, E. G. Overton, S. H. SPAIN Madrid-- Alfageme, B. Jimenez, J. G. SWEDEN Lidingo-- Rosell. A. F. Stockholm-- Gille. H. Theorell. H. G. T. U.S.S.R. Leningrad-- Sakouta, M. L. SCOTLAND Fife-- Knox, J. R. 58 PAST OFFICERS American Society of Heating and Ventilating Engineers 1894 President___ u----- ---------------------------Edward P. Bates 1st Vice-President........... ,,, Wm. M. Mackay end Vice-PresidentWilteie F. Wolfe 3rd Vice-President........................Chas. S. Onderdonk Treasurer--------------------------------- Judson A. Goodrich Secretary-------------------------------------------------- L. H. Hart 1897 President............... ........ --......... ...... Wm. M. Mackay 1st Vice-PresidentH. D. Crane end Vice-PresidentHenry Adams 3rd Vice-PresidentA. E. Kenrick Treasurer---------------------------------- Judson A. Goodrich Secretary-----------------------------------------H. M. Swetland Board of Managers Chairman, Fred P. Smith Henry Adams A. A. Cary Hugh J. Barron James A. Harding Edward P. Bates, Pres. L. H. Hart, Secy. Board of Managers Chairman, R. C. Carpenter . Edward P. Bates Stewart A. Jellett W. S. Hadaway, Jr. Wiltsie F. WoLfe Wm. M. Mackay, Pres. H. M. Swetland, Secy. Council Chairman, R. C. Carpenter Albert A. Cryer Chas. W. Newton F. W. Foster Ulysses G. Scollay. Secy. Council Chairman, Albert A. Cryer John A. Fish James Mackay Wm. McMannis B. F. Stangland 1895 President............ ..................................Stewart A. Jellett 1st Vice-PresidentWm. M. Mackay 2nd Vice-President________ ...... Cha^. S. Onderdonk 3rd Vice-PresidentD. M. Quay Treasurer------------------------------ --Judson A. Goodrich Secretary-------------:------------------------------------ L. H. Hart Board of Managers Chairman, James A. Harding Geo. B. Cobb Ulysses G. Scollay Wm. McMannis B. F. Stangland Stewart A. Jellett, Pres. L. H. Hart. Secy. Council Chairman, R. C. Carpenter Henry Adams ' T. J. Waters Edward P.' Bates Albert A.- Cryer, Secy. 1898 President-----------------------------------------Wiltsie F. Wolfe 1st Vice-PresidentJ. H. Kinealy 2nd Vice-PresidentA. E. Kenrick 3rd Vice-President.John A. Fish Treasurer------------ -------------- ------- Judson A. Goodrich Secretary---------------------:Stewart A. Jellett Board of Managers Chairman, Wm. M, Mackay Thomas Barwick A. C. Mott John A. Connolly . Frands A. Williams Wiltsie F. Wolfe, Pres. Stewart A. Jellett, Secy, Council - Chairman, R. C. Carpenter Henry Adams W. S. Hadaway, Jr. Albert A. Cryer Wm. McMannis Wiltsie F. Wolfe, Pres. Stewart A. Jellett, Secy. 1896 President----------------------------------------- R. C. Carpenter 1st Vice-PresidentD. M. Quay 2nd Vice-PresidentEdward P. Bates 3rd Vice-PresidentF. W. Foster Treasurer-----------------------------------Judson A. Goodrich Secretary.--------------------------------------------------L. H. Hart Board of Managers Chairman, Wm. M. Mackay Hugh J. Barron Stewart A. Jellett W. S. Hadaway. Jr. Wiltsie F. Wolfe R. C. Carpenter, Pres. L. H. Hart, Secy. _ Council . Chairman, A. A. Cary Albert A. Cryer B. F. Stangland Wm. McMannis J. J. Blackmore, Seey. 1899 President.---------------- --...... -...... H^nry Adams 1st Vice-President.______________ _______ D. M. Quay 2nd Vice-PresidentA. E. Kenrick 3rd Vice-President .... EVanrifl A. Williams Treasurer----- ------------------ .. . ..Judson A. Goodrich Secretary .................... ...........--.....Wm- M. Mackay Board of Managers Chairman, Stewart A. Jellett B. H. Carpenter Wm. Kent A. A. Cary Wiltsie F. Wolfe Henry Adams, Pres. Wm. M. Mackay, Secy. Council Chairman, R. C. Carpenter John Gormly Wm. McMannis W. S. Hadaway, Jr. B. F. Stangland Henry Adams. Pres. Wm. M. Mackay, Secy. 59 American Society of Heating and Ventilating Engineers Guide, 1936 1900 President.. 1st Vice-President-- ..... D. M. Quay -A. E. Kenrick 2nd Vice-President_ -Francis A. Williams . Judann A. Goodrich Secretary_________________________ Wm. M. Mackay Board of Governors . Chairman, D. M. Quay Wm. Kent, Vice-Chm. D. M. Nesbit R. C .Carpenter C. B. J. Snyder John Gormly Wm. M. Mackay, Secy. President..................... 1st Vice-President-- nd Vice-President Treasurer_______ _-- Secretary.____ _-- 1905 .Wm Kent _R. P. Bolton ____C. B. J. Snyder ,,Ulysses G. Scollay __Wm. M. Mackay Board of Governors Chairman, Wm. Kent R. P. Bolton James Mackay C. B. J. Snyder B. F. Stangland B. H. Carpenter J. C. F. Trachsel A. B. Franklin Wm. M. Mackay. Secy. 1901 PresidentJ. H. Kinealy 1st Vice-President-___________________ A. E. Kenrick 2nd Vice-President_________________ Andrew Harvey Treasurer________________ ----Judson A. Goodrich Secretary.1_________________________ Wm. M. Mackay Board, of Governors Chairman, J. H. Kinealy ' Wm. Kent. Vice-Chm. John Gormly . R. C. Carpenter C. B. J. Snyder R. P. Bolton Wm. M. Mackay, Secy. 1900 President_____ --John Gormly 1st Vice-PresidentI----------------------------C. B. J. Snyder gnd Vice-President:-------------------------------T. J. Waters Treasurer _____________________ __ Ulysses G. Scollay Secretary._____ ____________________Wm. M. Mackay Board of Governors Chairman, John Gormly C. B. J. Snyder,Vice-Chm. James Mackay R. C. Carpenter B. F. Stangland Frank K. Chew T. J. Waters A. B. Franklin Wm. M. Mackay, Secy. 1902 President`-------------------------------- ----------- A. E. Kenrick 1st Vice-President________ Andrew Harvey 2nd Vice-President_____________ Robert C. Clarkson Treasurer--Judson A. Goodrich Secretary.Wm. M. Mackay ' Board of Governors Chairman, A. E. Kenrick John Gormly, Vice-Chm. J. H. Kinealy R. C. Carpenter C. B. J. Snyder Wm. Kent Wm. M. Mackay. Secy. 1907 PresidentC. B. J. Snyder 1st Vice-President............................--James Mackay 2nd Vice-President.Wm. G. Snow Treasurer........... ....................... ..........Ulysses G. Scollay Secretary.______ Wm. M. Mackay Board of Governors Chairman, C. B. J. Snyder James Mackay ,Vice-Chm. Frank K. Chew R. E. Atkinson A. B. Franklin R. C. Carpenter Wm. G. Snow Edmund F. Capron Wm. M. Mackay. Secy. 1903 President_______ __________ ...H. D. Crane' 1st Vice-President.______________ -------------Wm. Kent 2nd Vice-President!;------------- .-------- :--R. P. Bolton Treasurer_:Judson A. Goodrich. Secretary_____Wm. M. Mackay Board of Governors . Chairman, H. D. Crane C. B. J. Snyder, Vice-Chm. A. E. Kenrick . R. C. Carpenter Geo. Mehring . John Gormly * Wm. M. Mackay, Secy. 1908 President. .................. :James Mackay 1st Vice-PresidentJas. D. Hoffman 2nd Vice-President___ !----------------- B. F. Stangland Treasurer-Ulysses G. Scollay Secretary ,, ,, --__________ _____ Wm. M. Mackay Board of Governors . . Chairman, James Mackay Jas. D; Hoffman,Vice-Chm. John F. Hale B. F. Stangland August Kehm R. C. Carpenter C. B. J. Snyder . Frank K. Chew Wm. M. Mackay, Secy. 1904 President.___________________ -______ Andrew Harvey 1st Vice-President.....--.......... ....................John Gormly 2nd Vice-President...__________ -Robert C. Clarkson TreasurerUlysses G. Scollay Secretary::Wm. M. Mackay Board of Governors . Chairman, Andrew Harvey John Gormly ' Hi D. Crane .. Robert C. Clarkson A. E. Kenrick . J. J. Blackmore C. B. J. Snyder R. C. Carpenter Wm. M. Mackay, Secy. 1909 President______ __:-------------------------------Wm. G. Snow 1st Vice-President______ ____ _________ August Kehm 2nd Vice-PresidentB. S. Harmon Treasurer--:__________________ --.Ulysses G. Scollay Secretary_________________________ -Wm. M. Mackay Board of Governors Chairman, Wm. G. Snow . ^ August Kehm, Vice-Chm. Samuel R. Lewis ' John R. Allen . Tames Mackay , . R. C. Carpenter B. F. Stangland B. S. Harrison Wm. M. Mackay, Secy. Roll of Membership 1910 President....... .................... ......... ......... Jas. D. Hoffman 1st Vice-President __________________ R. p. Bolton end Vice-President_______ .Samuel R. Lewis Treasurer------------------- --------------- Ulysses G. Scollay Secretary-------------------------- ----- ------ Wm. M. Mackay Board of Governors Chairman, Jas. D. Hoffman R. P. Bolton, Vice-Chm. John F. Hale Geo. W. Barr Samuel R. Leads . R. C. Carpenter James Mackay Judson A. Goodrich Wm. M. Mackay, Secy. 1915 President--------------------------1______Dwight D. Kimball 1st Vice-PresidentHarry M. Hart 2nd Vice-President.:L- r Frank T. Chapman Treasurer------------------------------ --____Homer Addatns Secretary-------------------------------------- --J. J. Blackmore Council Chairman, Dwight D. Kimball Harry M. Hart, Vice-Chm. Samuel R. Lewis Homer Addams Frank G. McCann Frank T. Chapman J. T. J. Mellon Frank I. Cooper Henry C. Meyer, Jr. E. Vernon Hill Arthur K. Ohmes Wm. M. Kingsbury J. J. Blackmore. Secy. President_ 1st Vice-President__ 2nd Vice-President._ Treasurer..... Secretary________ -- VR/ P-President ...... -A. B. Franklin -Ulysses G. Scollay ___ Wm. W. Macon 1" Vice-President.. 2nd Vice-Presidents Treasurer_______ ___ Secretary___________ 1916 _____ Harry M. Hart -Frank T. Chapman ___ Arthur K. Ohmes _____Homer Addams _____Casin W. Obert Board of Governors Chairman, R. P. Bolton . John R. Allen, Vice-Chm.- A. B. Franklin John T. Bradley Ja9. D. Hoffman R. C. Carpenter - August Kehm James H. Davis Wm. W. Macon, Secy. Council Chairman, Harry M. Hart ' F. T. Chapman, Vice-Chm. Dwight D. Kimball Homer Addams Henry C. Meyer, Jr. Charles R. Bishop Arthur.K. Ohmes . Frank I. Cooper Fred R. Still Milton W. Franklin Walter S. Timmis E. Vernon Hill Casin W. Obert, Secy. President._________ 1st Vice-Presidents 2nd Vice-Presidents Treasurer Secretary -John R. Allen -John F. Hale -Edmund F. Capron --James A. Donnelly ---Wm, W. Macon Board of Governors Chairman, John R. Allen John F. Hale, Vice-Chm. Dwight D. Kimball Edmund F. Capron Samuel R. Lewis R. P. Bolton Wm. M. Mackay Jas. D. Hoffman Wm. W. Macon, Secy. President 1st Vice-President__ 2nd Vice-President.. Treasurer.___ _______ Secretary_______ !___ 1913 ---------------- John F. Hale ....... ......_A. B. Franklin ------ Edmund F. Capron --.--James A. Donnelly -------------Edwin A. Scott . Board of Governors . Chairman, John F. Hale A. B. Franklin, Vice-Chm. James A. Donnelly John R. Allen Dwight D. Kimball Edmund F. Capron Wm. W. Macon R. P. Bolton James M. Stannard Frank T. Chapman Theodore Weinshank Ralph Collamore Edwin A. Scott, Secy. President.. .. 1st Vice-Presidents. 2nd Vice-President___ -__ Treasurer_________________ Secretary ____J. Irvine Lyle -Arthur K. Ohmes --Fred R. Still ___Homer Addams ___Casin W. Obert Council Chairman, J. Irvine Lyle A. K. Ohmes, Vice-Chm. Harry M. Hart . Homer Addams E. Vernon Hill Davis S. Boyden James M. Stannard ' Bert C. Davis Fred R. Still Milton W. Franklin Walter S. Timmis Charles A. Fuller Casin W. Obert, Secy. Presidents. 1st Vice-President.2nd Vice-President__ Treasurer Secretary------------- ------, 1918 ______ Fred R. Still -Walter S. Timmis ____ E. Vernon Hill --Homer Addams ___ Casin W. Obert Council .. ' Chairman, Fred R. Still ' W. S. Timmis, Vice-Chm.' J. Irvine Lyle : Homer Addams E. Vernon Hill William H. Driscoll Frank G. Phegley Howard H. Fielding Fred. W. Powers H. P. Gant Champlain L. Riley C. W. Kimball Casin W. Obert, Secy. President______ :___ _ 1st Vice-President__ 2nd Vice-Presidents Treasurer.__________ Secretary 1914 -Samuel R. Lewis _____ Edmund F. Capron --------Dwight D. Kimball --------- James A. Donnelly --!---..J. J. Blackmore Council . Chairman, Samuel R. Lewis E. F. Capron, Vice-Chm. John F. Hale Dwight D. Kimball Harry M. Hart JoH$ R. Allen Frank G. McCann Frank T. Chapman . Wm. W. Macon Frank I. Cooper James M. Stannard James A. Donnelly J. J. Blackmore, Secy. 1919 President.. 1st Vice-President_________ 2nd Vice-President________ Treasurer._______ ;______ Secretary____________ ______ -Walter S. Timmis -E. Vernon Hill -Milton W. Franklin _____ Homer Addams _____ Casin W. Obert . Council Chairman, Walter S. Timmis E. Vernon Hill, Vice-Chm. Frank G. Phegley Homer Addams Fred. W. Powers Howard H. Fielding Robt. W. Pryor, Jr. Milton W. Franklin Champlain L. Riley . Harry E. Gerrish Fred R. Still George B. Nichols Casin W. Obert, Secy. 61 of and 1936American Society Heating Ventilating Engineers Guide, 1920 PresidentE. Vernon Hill 1st Vice-President______________Champlain L. Riley Bnd Vice-President-________________.Jay R. McColl Treasurer_________ Homer Addams Secretary.:Caain W. Obert Council Chairman, E. Vernon Hill C. L. Riley. Vice-Chm. Jay R. McColl Homer Addams George B. Nichols Jos. A. Cutler Robt. W. Pryor, Jr. Wm. H. Driscoll W. S. Timmis A. C. Edgar Perry West Alfred Kellogg Casin W. Obert, Secy. 1924 PresidentHomer Addams 1st Vice-President________ .______ _____ S. E. Dibble Bnd Vice-President----------William H. Driscoll Treasurer-___ `,,._____________ :Perry West Secretary_____F. C. Houghten Council Chairman, Homer Addams S. E. Dibble, Vice-Ckm. W. E. Gillham F. Paul Anderson L. A. Harding W. H. Carrier Alfred Kellogg J. A. Cutler Thornton Lewis William H. Driscoll Perry West H. P. Gant F. C. Houghten. Secy. 1921 1925 PresidentChamplain L. Riley President_____________________________________ _____ _S. E. Dibble 1st Virs-Pr/tiiAmlrl__T....Jay R. McColl 1st , , -- - .... Wm. H. Driscoll Bnd Vice-President--H. P. Gant Bnd Vice-President_______________________ __ ;-----------F. Paul Anderson TreasurerHomer Addams Treasurer_____________________________________________ _____________ Perry West SecretaryCasin W. Obert Secretary___________________________________________ ----------------F. C. Houghten - Council Chairman, Champlain L. Riley Jay R- McColl, Vice-Chm.* E. S. Hallett Homer Addams E. Vernon Hill Jos. A. Cutler Alfred Kellogg Samuel E. Dibble E. E. McNair Wm. H. Driscoll Perry West H. P. Gant Casin W. Obert, Secy'. Council Chairman, S. E. Dibble Wm. H. T>nocoVl,Vice-Chm. W. T. Jones Homer Addams F. Paul Anderson W. H. Carrier Thornt' on 'Lewis J. H. Walker Perry West J. A. Cutler W. E. Gillham A. C. Willard F. C. Houghten, Secy. 1922 1926 PresidentJay R. McColl President____________ __ _____________ W. H. Driscoll 1st Vice-President-H. P. Gant 1st Vice-President.F. Paul Anderson Bnd v***-J>r***A**t ...... .................. Samiipl E. Dibble Bnd Vice-President--------------------------A. C. Willard Treat***** ,, W^fr Treasurer;..................... ....... ..................... W. E. Gillham SecretaryCasin W. Obert Secretary..................................................................................... ......... -A. V. Hutchinson Council Chairman, Jay R. McColl. H. P. Gant. Vice-Chm. L. A. Harding Homer Addams Jos. A. Cutler E. .E......M....c..N....a..ir H. J. Meyer Samuel E. Dibble Wm. H. Driscoll E. S. Hallett C. L. Riley Perry West Casin W. Obert, Secy. Council Chairman, W. H. Driscoll F. Paul Anderson, Vice-Chm, C. V. Haynes W. H. Carrier W. T. J"ones J. A. Cutler E. B. Langenberg S. E. Dibble Thornton Lewis W. E. Gillham J. F. Mclntire A. C. Willard 1923 President:-------------------------------------------------H. P. Gant 1st Vice-President________ ;Homer Addams Bnd Vice-President______;------------------- E, E. McNair Treasurer_________________ ________ Wm. H. Driscoll Secretaryl____________________C. W. Obert Council Chairman, H. P. Gant Homer Addams, Vice-Chm. E. S. Hallett W. H. Carrier Alfred Kellogg J. A. Cutler Thornton Lewis S. E. Dibble . E. E. McNair Wm. H. Driscoll Perry West ` Casin W. Obert, Secy. . 1927 PresidentJ. ..... .......F. Paul Anderson 1st Vice-President______ -.......... ........A. C. Willard Bnd --.....- Thnmtnn Lewis Treasure* . ---------------W. E. Gillham Secretary'....................................... .'.-- A. V. Hutchinson Council Chairman, F. Paul Anderson A. C. Willard, Vice-Chm. John Howatt H. H. Angus W. T. Jones W. H. Carrier J. J. Kissick W. H. Driscoll E. B. Langenberg Roswell Farnham Thornton Lewis H. H. Fielding J. F. Mclntire W. E. Gillham H. Lee Moore C. V. Haynes F. B. Rowley Roll of Membership 1928 President______________ 1st Vice-President__ __ Bnd Vice-President---. Treasurer___________ __ Secretary. --A. C. Willard __Thornton Lewis "~W. e`. Crtllham _A. V. Hutchinson Council. Chairman, A. C. Willard Thornton Lewis, Vice-Chm. C. V. Haynes F. Paul Anderson John Howatt H. H. Angus . W. T. Jones W. H. Carrier J. J. Kissick N. W. Downes E. B. Langenberg Roswell Farnham J, F. Mclntire W. E. Gillham H. Lee Moore F. B. Rowley President-- 1st Vice-President__ Bnd Vice-President-- Treasurer___________ Secretary1 Technical Secretary.. 1932 .____ F. B. Rowley ----------- W. T. Jones -------- C. V. Haynes .......F. D. Mensing .A. V. Hutchinson ________P. D. Close Council Chairman, F. B. Rowley W. T. Jones, Vice-Chm. F. E. Giesecke D. S. Boyden E. H. Gurney E. K. Campbell C. V. Haynes R. H. Carpenter John Howatt W. H. Carrier G. L. Larson John D. Cassell J. F. Mclntire E. O. Eastwood F. D. Mensing Roswell Farnham W. E. Stark President- ........ 1st Vice-President-- Bnd Vice-presidentTreasurer___________ Secretary-- Technical Secretary-- 1929 .Thornton Lewis ___ L. A. Harding ___ W. H. Carrier -A. V. Hutchinson _______ P. D. Close Council Chairman, Thornton Lewis L. A. Harding, Vice-Chm. John Howatt H. H. Angus W. T. Jones W. H. Carrier E. B. Langenberg N. W. Downes G. L. Larson Roswell Farnham F. C. McIntosh W. E. Gillham W. A. Rowe C. V. Haynes F. B. Rowley A. C. Willard President.. Bnd Vice-PresidentTreasurer.__________ Secretary___________ ---------- W. T. Jones -------- C. V. Haynes -------- John Howatt -------- D. S. Boyden -A. V. Hutchinson Council Chairman, W. T. Jones C. V. Haynes, Vice-Chm. E. H. Gurney D. S. Boyden E. K. Campbell J"o*hn Howatt G. L. Larson R. H. Carpenter J, F. Mclntire J. D. Cassell E. O. Eastwood F. C. McIntosh L. W. Moon R. Farnham F. B. Rowley F. E. Giesecke W. E. Stark President___ ____ 1st Vice-President-- Bnd Vice-PresidentTreasurer___________ Secretary-- Technical Secretary-- 1930 ,,L. A. Harding _W. H. Carrier _.F. B. Rowley C. W. Farrar -A. V. Hutchinson ----------- P. D. Close Council ' Chairman, L. A. Harding W. _H. Carrier, Vice-Chm. John Howatt H. H. Angus W. T. Jones D. S. Boyden E. B. Langenberg R. H. Carpenter. G. L. Larson J. D. Cassell Thornton Lewis N. W. Downes F. C. McIntosh Roswell Farnham W. A. Rowe C. W. Farrar F. B. Rowley Pre.s.id. en_t- .. lst Vtce-Prestdent. Bnd Vice-PresidentTreasurer.__________ Secretary.___________ 1934 -C. V. Haynes ..John Howatt ...G. L. Larson ..D. S. Boyden __A. V. Hutchinson Council Chairman, C. V. Haynes John Howatt, Vice-Chm. W. T. Jones M. C. Beman G. L. Larson D. S. Boyden J. F.. Mclntire Albert Buenger F. C. McIntosh R. H. Carpenter L. Walter Moon J. D. Cassell O. W. Ott F. E. Giesecke W. A. Russell E. H. Gurney W. E. Stark President 1st Vice-PrcsidcntSnd Vice-PresidentTreasurer___________ SecretaryTechnical Secretary,, 1931 ._W. H, Carrier ___ F. B. Rowley ____ W. T. Jones _F. D. Mensing i. V. Hutchinson _____ P. D. Close - Council ' * Chairman, W. H. Carrier F. B. Rowley, Vice-Chm. L. A. Harding D. S. Boyden John Howatt E. K. Campbell W. T. Jones R* H. Carpenter . E. B. Langenberg J. D. Cassell G. L. Larson v E. O. Eastwood F. C. McIntosh Roswell Farnham F. D. Mensing E. H. Gurney W. A. Rowe G. L. M. C. Beman D. S. Boyden Albert Buenger R. H. Carpenter J. D. Cassell F. E. Giesecke E. H. G*irney 63 John Howatt G. L. Larson --D. S. Boyden ____ A. J. Offner ------A. V. Hutchinson ohn Howatt C. V. Haynes J. F. Mclntire F. C. McIntosh L. Walter Moon Offner, A. J. O. W. Ott ' W. A. Russell W. E. Stark