Document rppemM9VGNO3qB5KOXDb3VY5q

FILE NAME: Ingersoll Rand (IRD) DATE: 1948 DOC#: IRD009 DOCUMENT DESCRIPTION: Heating Ventilating Air Conditioning Guide HEATING VENTILATING AIR CONDITIONING GUIDE 1948 An Instrument of Service Prepared for the Profession containing A TECHNICAL DATA SECTION o f r e f e r e n c e m a t e r ia l on t h e DESIGN AND SPECIFICATION OF HEATING, VENTILATING AND AIR CONDI TIONING SYSTEMS BASED ON-- THE TRANSACTIONS-- THE INVESTIGATIONS o f t h e R e sea r c h L aboratory and Co o pe r a t in g I n stit u tio n s-- and t h e P ra c tice o f t h e M em bers and frien d s of t h e S o c ie t y ; A MANUFACTURERS5 CATALOG DATA SECTION c o n ta in in g e sse n t ia l AND RELIABLE INFORMATION CONCERNING MODERN EQUIPMENT: THE ROLL OF MEMBERSHIP OF THE SOCIETY; COMPLETE INDEXES t o T e c h n ic a l and C a t a l o g D ata S e c t io n s . V o l. 2 6 $7.50 per Copy P ublished A nn ually by Am er ic a n So c ie t y o f H e a t in g and Ve n t ila tin g En g in e e r s 51 Madison Avenue N'ew York 10, N. Y. ? j Sngineeriza i-ibrary . Copyright 1948 BY T H E A m erican Society of H eating and V entilating E ngineers A |D IT ' D M cX TEb To t h e A d v a n cem en t o f T h e P rofession and ' I ts A llied I ndustries t e x t and illu stra tio n s are fu l l y p r o t e c t e d BY COPYRIGHT AND NOTHING THAT; APPEARS MAY BE REPRINTED EITHER WHOLLY OR IN PART W ITHOUT SPECIAL PERMISSION. 5 Printed and Bound by T he H orn-Shafer Company BALTIMORE r MARYLAND U. S. A. PREFACE TO THE 26th EDITIONJ94S T HE 26th edition of The Heating, Ventilating, Air Conditioning Guide contint^ the tradition of previous Guides in presenting current engineering practice an up-to-date products of manufacturers. t `* Among the chapters given most extensive revision n the 1948 edition, the following v ... should be noted: Chapter 10, Air Contaminants, contains revised limits for toxic gases, vapors, fumes, mists and dusts, in conformity with recent conclusions of industrial hygienists. Chapter 11, Instruments and Measurements, has been enlarged to include a greater number of instruments, as well as more information on test methods and the use of instruments. Chapter 12, Physiological Principles, incorporates some additional findings based upon recent research. Chapter 13, Air Conditioning in the Prevention and Treatment of Disease, has been revised to agree with current thought and research. Chapter 14, Heating Load, includes an enlarged list of approximately 350 localities, including city office and airport stations, for which weather data and design temperatures are given. The list includes data obtained from the U. S. Weather Bureau and Canadian Air Services, Meteorological Division. A new map showing isotherms of outdoor tem perature has been provided. Chapter 15, Cooling Load, has been increased to 45 pages to permit inclusion of an enlarged list of 315 localities for which weather data are listed. The chapter has also been rewritten to assist the user in applying the principles of periodic heat flow, and the data from most recent ASHVE research on solar heat transmission. Chapter 20, Estimating Fuel Consumption for Space Heating, includes an enlarged list of 211 U. S. cities and 25 Canadian cities showing monthly degree-day values. The information has been obtained from latest statistics of the U, S. Weather Bureau and Canadian Air Services, Meteorological Division. Chapter 21, Gravity Warm Air Systems, has been rearranged to facilitate use of the design tables. Chapter 22, Mechanical Warm Air Systems, contains an added section referring to method of designing large systems. In Chapter 23, Steam Heating Systems and Piping, revised descriptions of various types of systems keep the chapter up to date. Many new diagrams have been added to illustrate current practice. In Chapter 25, Radiators, Convectors and Coils, there has been added a section on baseboard radiation. In Chapter 26, Unit Heaters, Unit Ventilators, Unit Humidifiers, piping diagrams and text have been changed to comply with current practice. In Chapter 27, Pipe, Fittings and Welding, the section on welding has been expanded with reference to proper welding procedure and applicable code requirements. Chapter 30, Electric Heating, includes an enlarged list of pertinent references. Chapter 32, Fans, has been improved by addition of typical sound level curves to the fan performance curves. A new diagram illustrating accepted designations of direction of rotation and discharge for fans has been added. The chapter also contains a section on attic fans which has been transferred from Chapter 36. Chapter 34t Automatic Control, has been rewritten to include more detailed treatment of typical controls and control combinations for all types of systems. , Chapter 36, Unit Air Conditioners, Unit Air Coolers, has been revised and improved in both text and illustrations. Chapter 37, Spray Apparatus, has been rearranged and includes new information on design and use of air washers, cooling towers and spray ponds. Chapter 40, Air Distribution, has been completely revised by the ASHVE Technical Advisory Committee on Air Distribution and Air Friction. It contains new definitions and formulas for air distribution. Charts have been included for graphical solution of problems involving flow of air from slots and jets, residual velocity and size of openings. Information on location of outlets has been enlarged, and more information is given on control of air streams in spaces. M553558 C hapter 10 AIR CONTAMINANTS Classification of Air Contam inants; Sizes of Airborne Particles; Air Pollution by Smoke, Ash and Cinders; Sm oke A batem ent; Odor Nuisance; M axim um Allowable Concentrations o f Industrial Air Contaminants; Flammable Gases and V apors; C om bustible D usts; Atm ospheric P ollen; A ir borne Bacteria THE normal constituents of the earth's atmosphere are oxygen, nitrogen, carbon dioxide, water vapor, argon, small or negligible amounts of other inert gases, hydrogen, variable traces of ozone, and small quantities of microscopic and submicroscopic solid matter, sometimes called permanent atmospheric im purities. From the viewpoint of the air conditioning engineer, all other airborne substances may be termed con taminants. This term is applied preferably, however, to undesirable or chance impurities, since the occasion may arise for adding to the air controlled amounts of substances such as; solid or gaseous diluents for the prevention of explosions; germicidal mists or aerosols for bacteria control; masking substances for odor control; or a substitute for one of the normal gases, as, for example, when helium is used to replace nitrogen in atmospheres for compressed air workers or divers. The control of air quality is one of the functions of complete air con ditioning, and some knowledge of the composition, concentration and properties of air contaminants under various circumstances is therefore essential. Air contaminants arise from the normal processes of wear, erosion, windstorm, sea-spray evaporation, thermal disintegration, earthquake, volcanic eruption, combustion, manufacturing, transportation, agricul ture, and the biochemical or biological processes of life. They are classi fied at various times as organic and inorganic, visible or invisible, micro scopic or macroscopic, particulate or gaseous, toxic or harmless, beneficial or destructive. The following classification is based chiefly upon the origin or method of formation of air contaminants, using distinctions that are necessarily arbitrary in some cases. CLASSIFICATION OF AIR CONTAMINANTS Dusts, Fumes, and Smokes are solid particulate air contaminants. Dusts are solid particles projected into the air by natural forces, such as Wind, volcanic eruption or earthquake, and by mechanical or man-made processes, such as crushing, grinding, milling, drilling, demolition, shovelling, conveying, screening, bagging and sweeping. Some of these forces produce dust from larger masses, while the others simply disperse materials that are already in dust or pulverized form. Generally, partidesare not called dust unless they are smaller than about 100 microns in size. Dusts may be of mineral type, such as rock, ore, metal, sand; vegetable, such as grain, flour, wood, cotton, pollen; or animal, such as wool, hair, silk, feathers, leather. Fumes are solid particles commonly formed by the condensation of vapors from normally solid materials such as molten metals. Metallic fumes generally occur as the oxides in air because of the highly reactive nature of finely divided matter. Fumes may also be formed by sublimation, distillation, calcination, or chemical reaction, whenever such processes create airborne particles predominately below the 1 micron size. Fumes permitted to age tend to flocculate into clumps or aggregates of much larger size and this tendency may facilitate removal from air under controlled conditions. Smokes are the extremely small solid particles produced by incomplete combustion of organic substances such as tobacco, wood, coal, oil, tar and other carbonaceous 166 A ir C o n ta m in a n ts 167 materials. The term smoke is commonly applied to the mixture of solid, liquid and gaseous products of combustion, although the technical literature prefers to distinguish between such components as soot or carbon particles, fly-ash, cinders, tarry matter, unbumed gases, and gaseous combustion products. The finest particulate constituents are characteristically much less than 1 micron in size, often in the range of 0.1 to 0.3 micron. Mists and Fogs are liquid particulate air contaminants. Mists are very small airborne droplets of materials that are ordinarily liquid at normal temperatures and pressures. They may be formed by atomizing, spraying, splashing, mixing, violent chemical reaction, electrolytic evolution of gas from a liquid, or escape of a dissolved gas upon release of pressure. The very small droplets expelled or atomized into the air by sneezing constitute mists containing microorganisms that become air contaminants. Fogs are limited by some classifications to airborne droplets formed by condensation from the vapor state. This arbitrary distinction between mist and fog is of minor importance, as both terms are used to indicate the particulate state of airborne liquids (occasionally termed aerosols). Fog nozzles are so named because of their ability to produce extra fine droplets as compared to the mist from ordinary spray devices. The highly volatile nature of some liquids quickly reduces their airborne droplets from the mist to the fog range, and eventually to the vapor phase until the air becomes saturated with that liquid. Many droplets in fogs or clouds are microscopic and submicroscopic in size, and may be conceived as the transition state between the larger mists and the vapors. Vapors and Gases are non-particulate air contaminants. Vapors are the gaseous phase of substances that are either liquid or solid in their commonly known state, examples being gasoline, kerosene, benzene, carbon tetrachloride, mercury, iodine, camphor. Vapors may be changed to the solid or liquid form by in creasing the pressure, decreasing the temperature or applying both processes simultan eously. They are removed from the air by condensation with less difficulty than are the gases. Gases are normally formless fluids which tend, to occupy a space orenclosure completely and uniformly at ordinary temperatures and pressures. The following substances qualify as gases: oxygen, nitrogen, carbon dioxide, carbon monoxide, hydrogen, ammonia, sulfur dioxide. Gases, likewise, may be solidified or liquefied by the proper control of tem perature and pressure. The preceding classification is not suitable for the airborne living organisms, which range in size from the submicroscopic viruses to the largest pollen grains, not considering the smallest insect life. Bacteria range from about 0.2 to 5 microns in size, fungus spores from 1 to 10 microns, and pollen from 5 to 150 microns. SIZES OF A IRBO RN E PA RTICLES Fig. 1 is a graphic tabulation of the properties of airborne solids and liquids arranged according to size on the micron scale. There are 25,400 microns in 1 inch. Particles larger than 10 microns are unlikely to remain suspended in air currents of moderate strength, but settle out by gravity at speeds dependent upon the shape, the size and specific gravity of the particle, the wind velocity, the orientation of the collecting surface, and the topography. These larger particles are of major interest to the engineer in the solution of nuisance problems, but it is usually the smaller particles, or those below 10 microns, that remain in the air long enough to be of hygienic as well as economic significance. The great bulk of industrial dust particles is of the order of 1 micron in size. Tremendous numbers are also present in the sub-microscopic range below 0.5 micron, but those below 0.1 micron are not believed at 268 CHAPTER 10 1948 Guide LAWS OF SETTLING IN RELATION TO PARTICLE SIZE ( l im e s of dem a rca tio n a p p r o x . ) PARTICLES FALL WITH INCREASING VELOCITV oVcloctty cm./scc. OVdocity ft/mln dDiom. of partid e in cm. D*Diom. of particle'in Microns r Radius of par ticle in cm. g98l cm./scc.1 acceleration s,-Density of particle ^Density of Air (Very Small relative to s.) Viscosity of air in-poises H6l4-xlO"7 f o r oir ot 70 F. A- 10'5 cm. (Mean free path of gas molecules ) PARTICLES MOVE LIKE GAS MOLECULES A` Distance of motion in time t R G a s constant - 5.316 x 107 T Absolute Temperature N^Number of Gos molecules in one mol6.06xIO29 Compiled by W. G. Frank and Copyrighted. F ig. 1. S izes and Characteristics of A irborne Particulate M atter present to be of any practical importance, possibly due to their exceed ingly small mass in comparison with the balance of airborne matter. In fact, particles this small may become the permanent atmospheric impuri ties that have little if any opportunity of settling because of the continual motion imparted to them by air currents and the molecular activity of their supporting gases (Brownian Movement). The survey1of atmospheric pollution in 14 American cities conducted from 1931 to 1933 indicated the average size of outdoor dust particle to be 0.5 micron, as collected by the Owens jet dust counter and measured under the microscope. The inability of the light field microscope to Air C ontam inants m reveal particles in the 0.1 micron vicinity may have influenced the determination of average particle,size. The lower limit of particle size visible to the naked eye cannot be stated definitely. It depends nolronly upon the individual eye, but also upon the shape and color of the particle, the intensity and quality of the light, and the nature of the background or the opportunity for contrast. Under ideal conditions a particle of 10-micron siz might be recognized, while under less favorable conditions it may be impossible to distinguish a particle smaller than 50 microns. The lower limit of visibility probably ranges from 10 to 50 microns. Dusts, powders and granular materials are frequently classified byreference to the size of screens used for separation. Particles above 40 microns are said to be the screen sizes and those below, the sub-screen or' microscopic sizes. The approximate or theoretical sizes of particles corresponding to the mesh scale of the U. S. Standard Sieve Series are given in Table 1. Microscopic examination of screened dust indicates that the average diameter of a sample of irregular particles may be substantially larger than the openings of the screen through which it has passed, if the particle Table 1. Relation of Screen M esh to Particle Size U . S. S tan d ard S ie v e M e s h .......... 4 00 325 200 140 100 60 35 18 N o m in al Sieve O p en in g in M ic r o n s ................. 3 7 44 74 105 149 250 500 1000 shapes deviate considerably from the spherical form 2. The smallest dimension of many such particles will correspond with the maximum permissible distance between the wires of commercial screens made to A S T M Standard specifications. Screening does not give sharp separation into size groups, and accordingly such a classification is statistical rather than absolute. A IR POLLUTION BY SMOKE, ASH AND CINDERS The total airborne solids settling in urban areas are usually reported as soot fa ll in tons per (square mile) (month). Such data published for the cities in this country range from 20 to 200 tons per (square mile) (month). To the air conditioning engineer this information may indicate the effectiveness of smoke abatement or fuel combustion control methods in his locality, but it does not provide a suitable index of the suspended dust that air cleaners in a ventilating system are expected to capture3| 4' 5. Gravimetric or weight data of the type given in Table 2 are preferable. In some cases airborne particle counts may be necessary, as for pollen, bacteria, spores, and insoluble dusts causing illness or lung disease. Dust concentrations by weight cannot be converted readily to con centrations by particle count because of the variability of particle size, shape and specific gravity, and the inherent characteristics of dust counting and weighing procedures. One milligram of dust per cubic 170 CH APTER 10 1948 G uide meter of air may represent dust counts from 1 million to 100 million particles per cubic foot of air (lightfield microscope technic) according to the size distribution of the airborne dust sample. Information of this type for a specified application is best obtained by simultaneous sampling for both counting and weighing and noting carefully at the time all factors th at might affect the reproducibility of the count-weight ratio. Smoke Abatement Successful abatement of atmospheric pollution caused by smoke re quires the combined efforts of the combustion engineer, industrial execu tive, public health officer, city planning commission and the community at large. Electrification of industry and railroads, increases in the use of domestic oil and gas furnaces, and segregation of industrial districts is gradually providing effective aid in the solution of this problem. In the large cities where nuisance from smoke, fly-ash and cinders is more serious, limited areas obtain some relief by the use of district heating. Time, temperature and turbulence are fundamental requirements for smokeless combustion. Increase of any one of these factors will reduce T able 2. D ust Concentration Ranges L oca tio n R u r a l a n d s u b u r b a n d i s t r i c t s .................................... M e tr o p o l i t a n d i s t r i c t ........................................................ I n d u s t r i a l d i s t r i c t s ............................................................... O r d in a r y f a c to r ie s o r w o r k r o o m s ............................... E x c e s s iv e ly d u s t y f a c to r ie s o r m in e s ....................... M in im u m e x p lo s iv e c o n c e n tr a t io n s .......................... G rains pe r 1000 C u F t 0 .0 2 -0 .2 0 .0 4 -0 .4 0.1 -2 .0 0.2 -4 .0 4-400 4 0 0 0 -2 0 0 ,0 0 0 *1 grain per 1000 cu ft = 2.3 milligrams per cubic meter. I oz per cubic foot = 1 gram per liter = 1000 grama per cubic meter. M iillgram s p e r C u bic M et e r 0 .0 5 - 0.5 0 .1 - 1 .0 0.2 - 5.0 0.5 -1 0 10-1000 1 0 ,0 0 0 -5 0 0 ,0 0 0 the quantity of smoke discharged, although excessive turbulence in furnances may increase the output of ash and cinders. Special care must be taken in hand firing the bituminous coals. (See Chapters 16, 17 and 18 for further discussion on fuel burning technic). Legislative measures at the present time are largely concerned with reduction of the visible smoke discharged from chimneys of boiler plants. Practically all ordinances limit the number of minutes in any one hour that smoke of a specified density may be discharged, as measured by comparison with a Ringelmann Chart (Chapter 11, Instruments and Measurements). Ordinances generally do not make specific provision for control of the corrosive and irritant gases, such as oxides of sulphur and nitrogen discharged with the gases of combustion. Where high sulfur coals are burned, sulfur gases present a serious hazard to property, health and vegetation. In foggy weather the accumulation of these gases in the lower strata of the atmosphere may be such as to cause irritation of the eyes, nose and respiratory passages, and possibly even more dangerous consequences. The Meuse Valley (Belgium) fog disaster (1930) has become a classic example in the histoiy of gaseous air pollution. It is believed that sulfur dioxide and other toxic gases released in a rare combination of atmospheric Air C ontam inants 171 calm and dense fog were responsible for about 60 human deaths, injuries to several hundred persons^ and also the death of many domestic and wild animals. 4 A bsorption of Solar Radiation The absorption of solar ultraviolet light by smoke and soot, is recog nized as a health problem in many industrial cities. Measurements of solar radiation in Baltimore6 by actinic methods demonstrated that ultraviolet light intensity in the country was 50 per cent greater than in the city. In New York City 7 a loss as great as 50 per cent in visible light was found by photo-electric cell. ODOR NUISANCE A problem companionate with smoke abatement is the control of odor nuisance in the neighborhood of industrial plants discharging noxious or offensive air contaminants. Community planning and zoning will avoid much of the difficulty in the future, but meanwhile many industrial cities must resort to corrective measures by requiring the installation of air cleaning devices, the alteration of manufacturing processes, or by legal termination of the offensive operation in residential or commercial districts. The control of outdoor odor nuisance is especially troublesome because of the extremely minute quantities of contaminant that are capable of offending through a wide area. New industrial chemicals with strange or unfamiliar odors tend to receive much more attention from the neigh borhood than the customary odors generated by well known processes and raw materials. Methods of odor control currently in use include charcoal adsorption, scrubbing towers and air washers, chlorination, condensation, masking, passage of the odorous air through combustion chambers, and best of all, substitution of less offensive materials whenever possible 8t 9i 10, n. The control of air quality within buildings ventilated for human occupancy is discussed in Chapter 12. Tobacco smoke odors, cooking odors and body odors are air contaminants of the nuisance type which now command a decisive position in the standards of air quality for indoor comfort. However, the engineer will find, at times, that odors originating outside buildings in industrial or business districts may determine the kind and capacity of equipment he must provide for a high quality air supply installation. INDUSTRIAL AIR CONTAMINANTS Many industrial processes are sources of contaminants. Their control is an important function of the ventilating or air conditioning engineer, because the atmosphere within buildings is the medium whereby such finely divided m atter is dispersed and transported from the source to remote locations where it may cause property damage, nuisance, fire, explosion, disease and even death. Tables 3, 4 and 5 give the maximum allowable concentrations for industrial air contaminants as currently accepted in most sections of the country. They apply to exposures of 8 hours per day, and refer to the quantities of contaminant permissible in the workers' breathing zone. Some of these figures may be altered as the result of continuous research, and some may differ from those in force in a few cities or states. The 172 C H A P T E R IO 1948 G uide Table 3.. Physiological Response to Gases and Vapors3 Concentrations in Parts of Substance per Million Parts of Air by Volume (ppm) Substance ! Rapidly Fatal Acrolein----------------------Ammonia________ __ ___ Amyl acetate Aniline.................... ............ Arsine........ .... ..... - ......... Benzene (benzol)____ ___ Bromine.Butyl acetate_______ ,___ CarBon dioxide.______ __ Carbon disulfide.--............. Carbr>n monoxide. ___ Carbon tetrachloride.____ Chlorine. _ _____ __ _ . Dichlorobenzene____ __ Dichloroethyl ether.______ Ether (diethyl)__ ____ _ Ethyl acetate___________ Ethyl alcohol ................ Ethylene dichloride............ ,, Formaldehyde........... .......... Gasoline.- .......................... Hydrogen chloride--............ Hydrogen cyanide...... ........ Hydrogen fiuoride...... ........ Hydrogen sulfide............ -... Methyl acetate................... Methyl alcohol (Methanol) Methyl bromide-................ Methyl chloride____ ___ -- Methylene chloride............. Mortochlnrohenzene.--........ N itrobenzene......... .............. Nitrogen oxides... ............... Phosgene.......... - ...... - ...... Phosphine.... ,,..... ........-- ... Styrene.--. ...___........... Sulfur dioxide.-.................... Tfttrarhlnrnethanp............. T*tr?*chlnroethylene .~ Toluene (toluol)................... Trichloroethylene.... .......... T u rp en tin e.. __ _ Xylene (xylol)..................... 2,000 5,000 250 20,000 500 100,000 2,000 4,000 50,000 1,000 -- 1700 -- 1,000 200 600 -- 20,000 150,000 300 50 1,000 400 7,000 "20*000 IS o o o D angerous tq L ife in H to 1 Hr 100 2,500 200 10 5,000 40 lo.ooo 50,000 1,000 1,000 10 500 35,000 10,000 4,000 -- ------ 100 50 200 -- 2,000 20,000 100 5 400 Ti.irr-,,,ii- 150 5,000 5,000 Maximum Allow able Concentration for Daily Exposures 0.5 100 200 5 0.05 100b 1 200 5,000 20b 100b 50 1 50 15 400 400 1,000 100 10b 500 10 20 3 20b 200 200b 20 100 500 75 1 25b 1 0.05 400b 10 5 100 200 200b 100 200b Adapted from: M anual of Industrial Hygiene, b y \V. M. Gafafer et al, U. S. Public Health Service (W. B. Saunders Co., 1943); Analytical Chemistry of Industrial Poisons. Hazards and Solvents, by M . B. Jacobs (Interscience Publishers, 1941); Noxious Gases, by Henderson and Haggard (RdnhoJd Publishing Co., N. Y-, 1943). 1947 report of the Committee on Threshold Limits of tne American Conference of Governmental Industrial Hygienists; and other authoritative sources. ^Adopted by the American Standards Association (American Standard Z-37). prudent engineer will design equipm ent using these values as the upper limits of air contamination, and will incorporate a reasonable margin of safety in his estimates of ventilation capacity. Information on the properties and effects, with respect to health, of Air C ontam inants 173 T able 4. M aximum Allowable Concentrations of, D usts, F umes and M ists Substance Antimony ........ . Arsenic; arsenic trioxide..__^...*......,,................................... 1. Cadmium, and compounds . ................................................... Cb 1orod iph enyIs.............................................................. _...... Chromic acid mist and Chromates (as CrOg)..,,,,,,,,.................. Fluorides................................... ............... .......___________ Lead; lead carbonate; lead chloride; lead nitrate; lead oxides; lead sulfate........................................................................ Manganese, and compounds....................... ............................ ....... Mercury, and compounds... .................................................. ......... Pentachlnrnnaphthalene.... . ______________________ Selen iurn........ .................. ....... ..............;______ ;.L.............. Tellurium...... ......................... . ........................................... T richloronaphthalene................................................. ..................... T rinitrotoluene._................................................................................ Zinc oxide fum e_____________________ - _________________ Milligrams per Ctrarc Meter, Datly Exposures* . 0.1 0.15c 0.1c 1.0 0.1 2.5 0.15c 6.0e 0.1 0.5 0.1 0.1 - 5.0 1.5 15.0 Adapted from: Manual of Industrial Hygiene, by W. M, Gafafer, et al, U. S, Public Health Service (W. B. Saunders Company, 1943); and other authoritative sources. bl milligram per cubic meter * 0.44 grain per 1000 cu.ft. cAdopted by the American Standards Association (American Standard 2-37). , j T able 5. M aximum Allowable Concentrations of D usts3 Substance A lu m in u m oxide a b ra s iv e .................................. .......... .......................... A sb e sto s.__ - ______ _______ ..................................................................... C arborundum (silicon carbide) ,, ... .................................... C e m e n t (Portland).... ..................... .................. ..................... ...... C oal (less th a n 5 p e r c e n t q u a r tz ) ___________________________ D u sts c o n ta in in g loss th a n 10 per c e n t free silica . ___ ____ G r a n i t e - ......................... .... .......................................................... ..... ........ G y p s u m (h y d ra te d c alciu m s u lfa te )___ .-- ----- ---------------------L im e sto n e (calcium c a rb o n a te )., .... ,,______________ ________ M a rb le (calciu m c a rb o n a te ) __ _______________________________ M ica..._ .............................................................................................................. Nuisance d u s ts (n o n -to x ic , n o n -silic a )................... - ...............- ........ Q u a rtz (silicon d io x id e )......... ...... .... .................................----------------S a n d (silica, silicon d io x id e )____________________ ___ ________.... S a n d s to n e ................ ........................ ................................... ....----------------- S ilica {free o r u n c o m b in e d silicon d io x id e )__________ _________ Silicates (rnrnhineri silicon dioxide) .................. ............... ...... ...... S l a t e - ------------------------- -----,,----------------------------------------------------- T a lc ................................................ .................. ................................................ T o ta l (m a x im u m c o n c e n tra tio n for m ixed d u s ts )...- ........... . Million P articles per Cubic F oot op Air , Daily E xposures* 15-100 5 15-100 50-100 50-100 10-100 10- 25 50-100 50-100 50-100 10-100 50-100 ^ 5 5 o 5 15-100 15-100 10- 50 50-100 Adapted from: Study of Asbestosis in Asbestos Textile Industry, U. S. Public Health Service Bulletin No. 241, 1938; Industrial Dust, by Drinker and Hatch (McGraw Hill Book Co., 193(5); Industrial Code Bulletin No. 35, New York State Department of Labor: recommendations of state and local industrial hygiene agencies compiled by the American Conference of Governmental Industrial Hygienista; and bother authoritative sources. ^Includes only particles from 1 to 10 microns approximately, as determined by the light field microscope counting technic, using the 10 X objective. Dark field counts (and the corresponding allowable concen trations) are anywhere from 2 to 100 times the light field counta for the same sample, according to the proportion of dust smaller than 1 micron (See Industrial Dust, Chapter VIT, by Drinker and Hatch, Mc Graw Hill Book Co,). specific industrial air contaminants has developed rapidly within the past decade into an extensive literature. Some of the more readily available publications are listed at the end of this chapter. 174 C H APTER 10 1948 G uide T able 6. Approximate Limits of F lammability of Single Gases and Vapors I n Air at Ordinary T emperatures and Pressuresa G as or Vapor A c e t a l d e h y d e ................................. A c e t o n e ............................................. A c e f y l e n e h __ __ A l l y l a l c o h o l ................................... A m m o n i a _____________________ A m y l a lc o h o l . ......................... A m yl ch lo rid e A m y l e n e ____________ ___ B e n z e n e ( b e n z o l ) ........................ B e n z y l c h l o r i d e . ___ ___ ______ B u t a n e . . . . .............................. ........... B u t y l a c e t a t e _____ ___________ B u t y l a l c o h o l ................................. B u t y l e n e ................ .......................... C a r b o n d i s u l f id e . ____________ Low er L imit P er cen t dy Volume 4 .0 2 .1 2 .5 2 .4 1 6 .0 1.2 1.4 1.6 1.4 1.1 1.6 1.7 1.7 1.7 1.0 Uppe r L imit P er cent by Volume 57 1 3 .0 80 2 7 .0 8 .0 - ....... 8.5 1 5 .0 Tilllu 9 .0 50 C losed C u p Flash P oint F D ego -1 7 0 70 91 12 140 -7 6 72 84 -2 2 n}':V-' I n C a r h o n m o n o x i d e _____ _ C r o t o n a l d e h y d e ........................... C y c l o h e x a n e ................. ................. C y c l o p r o p a n e ................................. D e c a n e . -- ....................................... D i c h l o r o e t h y l e n e ( 1 , 2 ) _____ Diethyl selenide.................. Dioxan............................ . Ethane... ............................ Ether (diethyl)_________ Ethyl acetate...................... Ethyl alcohol........ ...... ....... Ethyl bromide.................... Ethyl cellosolve...... ............ Ethyl chloride..................... Ethylene______________ Ethylene dichloride............ Ethyl formate.................... Ethyl nitrite........... ............ Ethylene oxide.......... ......... Furfural (125 C )________ Gasoline.TM............... .... Heptane........ ...................... Hexane ___ ..... ................ Hydrogen cyanide.............. Hydrogen. _________ H y d r o g e n s u l f i d e ....................... Illuminating gas_________ Tsn-hntvl afrnhni Iso-pentane.................. ....... Iso-propyl acetate.............. Iso-propvl alcohol ___ Methane.______________ 1 2 .5 2.1 1.3 2 .4 0 .6 7 9.7 2.5 2.0 3.1 1.7 2.2 3.3 . 6.7 2.6 3.6 3.0 6.2 2.7 3.0 3.0 2.1 1.3 1.0 1.2 5.6 4.1 4.3 5.3 1.7 1 .3 1.8 2.5 5.0 74 1 5 .5 8 .4 1 0 .3 2 .6 12.8 "22.2 15.0 48.0 11.5 19.0 11.3 15.7 14.8 34.0 15.9 16.5 80 "6.5 6.0 6.9 40.0 74 45.5 31.0 -- 7.8 15. *55 1 ,1T-r 115 43 65 . -20 24 55 ` 4 --58 56 -4 -31 140 -50 25 -7 0 82 43 53 -- Adapted from: Limita of Inflammability of Gases and Vapors, by H. F. Coward and G. W. Jones <U. S. Bureau of Mines. Bulletin No. 279, 1039); Properties of Flammable Liquids, Gases and Solids (As sociated Factory Mutual Fire Ina. Cos.. January. 1040); and National Fire Codes for Flammable Liquids, Gases. Chemicals and Explosives--1945 (National Fire Protection Association). ^Turbulent mixture, oClosed cup refers to the equipment used In flash point determinations. Air C on ta m in a n ts 175 T able 6. Approximate Limits of F lammability of Single Gases and Vapors I n Air at Ordinary T emperatures and Pressures" (Continued) Gas or Vapor M e th y l a c e ta te ........................ M e th y l alco h o l.......... .......... M e th y l b ro m id e ...... ................ M e th y l h n fy l k e to n p __ M e th y l c h lo rid e ..............,, A .. M e th y l c y c lo h e x a n e ...... ........ M e th y l e th y l e th e r .... ....... M e th y l e th y l k e to n e ______ M e th y l f o r m a te ___________ M e th y l p ro p y l k e to n e _____ N a tu r a l gras_______ N a p h th a (b e n z in e )-------- ----N a p h th a l e n e .- .......................... N o n a n e ........................ ......... ..... O c ta n e ................................ - ....... P a ra ld e h y d e ............................... P p n ta n p ... _______ ... P r o p a n e . ...... .................................. P r o p y l a c e ta te .......................... P r o p y l a lc o h o l................................ P ro p y len e ...........*.............. ............ P r o p y le n e d ic h lo rid e ................ Propylene o x id e..... ................. P y r id in e (70 C ) ............................. T o lu e n e (to lu o l)............................ T u r p e n t i n e ....................................... V i n y l e t h e r ................................. ........... V i n y l I n l o r i He.................. ......... W a tp r gras ( v a ria h lp ) X y le n e (x y lo l)------------------------ Lower L imit P er cent by V olume 3.1 '6.0 13.5 1.2 8.0 1.1 2.0 1.8 5.0 1.5 , 4.8 1.1 0.9 0.74 * 0.84 1.3 1.4 2.4 1.8 2.5 2.0 3.4 2.1 1.8 1.3 0.8 1.7 4.0 6.0 1.0 Upper Limit Per cent by Volume 15.5 36.5 14.5 8.0 19.7 __ io .i 11.5 22.7 8.2 13.5 6.0 2.9 3.2 8.6 9.5 8.0 -- 11.1 14.5 21.5 12.4 7.0 "27*0 2 2 .0 70 6.0 C losed Cui> Flash Point F D ego 15 54 , ____ 25 -3 5 30 ' -2 -- 20-45 174 88 56 _ 58 59 ~59 68 40 95 . .. 63 FLAMMABLE GASES AND VAPORS Adequate ventilation is a primary requirement for eliminating or minimizing the hazard of fire or explosion due to gases and vapors. The need for good ventilation is not removed by the use of other precautions, such as the elimination of known ignition sources, segregation of hazard ous operations, adoption of safe building construction, and installation of v automatic alarms. Some safety engineers regard overventilation of an operation employing flammable liquids as a legitimate operating charge for the privilege or necessity of using a dangerous process. ^ However, it is not possible to apply a reasonable safety factor to the ventilation estimate without consideration of the concentrations of gases or vapors that ap proach the danger point. Safety engineers prefer to limit the concen tration to lA or H of the lower explosive limit, and this fact should be given full weight in determining the capacity and design of ventilating equipment. Rarely should consideration be given to operation above the upper explosive limit in the open areas of buildings or rooms--even though unoccupied--because the danger of temporary drop of gas concentration to a point within th.e explosive range is top great. 176 CH APTER 10 1948 G uide The ability of'a flammable liquid to form explosive mixtures is de termined largely by its vapor pressure, volatility, or rate of evaporation. Flask point is a convenient method of expressing this property in terms of the temperature scale. It may be defined as the temperature to which a combustible liquid must be heated to produce a flash of flame when a small flame is passed across the surface of the liquid. The higher the flash point, the more safely can the liquid be handled. Liquids with flash points Under 70 F should be regarded as highly flammable. The upper and lower limits of flammability of gases and vapors, and the flash points of the corresponding liquids are given in Table 6. Methods for Estimating the flammable limits of mixtures of gases or vapors must be applied with caution; the reader is referred to other publications for this information12,1S. Design of equipment for the control of combustible anesthetics is outlined in Chapter 13. Construction of equipment for handling air containing flammable substances, or operating in atmospheres so con taminated, is discussed in Chapter 46. It is customary to report the concentrations of flammable gases or vapors in per cent by volume, or volume per cent. Comparison with concentrations on the part per million scale used in chemical, medical or industrial hygiene literature is readily made by the conversion: 1 per cent = 10,000 ppm (parts of contaminant per million parts of air, by volume, or in other words, cubic feet of contaminant per million cubic feet of air). It will be noted in Table 6 that nearly all of the substances listed have lower explosive limits above 1.0 per cent, while the maximum allowable concentrations for gases and vapors in Table 3 are below 1000 ppm or 0.1 per cent in most cases. Therefore, control of toxic or injurious vapors in workrooms to levels below their maximum allowable concen trations foi* health usually requires much more effective ventilation than for the prevention of a fire hazard. COMBUSTIBLE DUSTS A dust explosion is essentially a sudden pressure rise caused by the very rapid burning of airborne dust. The primary explosion often originates from a small amount of dust in suspension exposed to a source of ignition, and the pressure and vibration it creates may be sufficient to dislodge large accumulations of dust on horizontal ledges or surfaces of the building and equipment, thereby creating a secondary explosion of great force. Thus the air conditioning engineer is involved for two reasons: (1) to obtain a movement of dust-laden air into exhaust hoods or openings and through ventilating or pneumatic conveying ducts in a manner that will prevent accumulation of highly flammable dust at points where it could ignite inside the equipment; and (2) to so design process ventilation as to prevent the escape of dust which might settle on horizontal surfaces and become a potential source of disaster at some distance from the dusty operation. (See Chapter 46). The intensity of a dust explosion depends upon: the chqmical and thermal properties of the dust; the particle size and shape; the concen tration in air; the proportion of inert dust in the air; the moisture content and composition of the air; the size and temperature of the ignition source; and the degree of dispersion of the dust cloud. Investigations on the explosibility of dusts require a determination of the maximum pressure developed during an explosion of a known-air concentration, as well as Air C ontam inants 177 determination of the rate of pressure rise. Investigators frequently experience difficulty in obtaining dust suspensions of uniform dispersion, and this should be kept in mind when comparing results from several sources M. The minimum explosive concentrations of airborne dusts already tested range from 0.01 to 0.5 oz per cubic foot, or 10 to 500 grams per cubic meter of air'. Maximum pressures generated have been reported as high as 500 psi, although th e f are more likely to be of the order of 50 pi. Investigations on the flammable characteristics of dusts are currently made at 0.1 and 0.5 oz per cubic foot*16"21. ATMOSPHERIC POLLEN The properties of pollen grains discharged by weeds, grasses and trees and responsible for hay fever are of special interest to engineers who design equipment for their removal from indoor air (see Allergic Dis orders in Chapter 13, and Air Cleaning Devices, Chapter 33). Whole grains and fragments transported by the air range chiefly between 10 and 50 microns in size, but some have been measured as small as 5 microns and others over 100 microns in diameter. Ragweed pollen grains are fairly uniform in size within the range of 15 to 25 microns. Pollen grains can be removed from the air more readily than the parti cles of dust prevalent in outdoor air and found near dusty industrial processes, since the latter predominate in the range of 0.1 to 10 microns in size. Most grains are quite hygroscopic and therefore vary in weight with the humidity. Illustrations and data on individual pollen grains are available in the botanical literature 22,23,2i. Th geographical distribution of plants known to produce hay fever is also recorded 2G; 26. The quantity of pollen grains in the air is generally estimated by exposing an adhesive-coated glass plate outdoors for 24 hr and then counting calibrated areas under'the microscope. Methods are available for determining the number of grains in a measured volume of air 2bt 27t 28 but their greater accuracy has not caused them to replace the more simple gravity slide method used for most pollen counts. Counting technics vary somewhat, but the daily pollen counts reported in local newspapers during the hay fever season usually represent the number of grains found on 1.8 sq cm of a 24-hr gravity slide. H ay fever sufferers may notice the first symptoms when the pollen count is 10 to 25, and in some localities the maximum figures for the seasonal peak may approach 1000 for a 24-hr period, depending upon the sampling and reporting methods of the laboratory,'! Translation Of gravity counts by special formulas to a volumetric basis, or the number of grains per cubic yard_or per cubic foot of air, is still uncertain because of the com plexity of the modifying factors. When such information is important, it is best obtained directly by a volumetric instrument. The number of pollen grains per cubic yard of air evidently varies from 2 to 20 times the number found on 1 sq cm of a 24-hr gravity slide, depending on grain diameter, shape, specific gravity, wind velocity, humidity and physical placement of the collecting plate 26,80*'S1. AIRBORNE BACTERIA Study of the occurrence and significance of micro-organisms in the atmospheres of the indoor world is currently absorbing the energies of a 178 CHAPTER 10 1948 Guide substantial number of physicians, bacteriologists, aerobiologists, physi cists, public health workers, engineers and hospital personnel. Some data are available on the types and quantities of bacteria found in a variety of occupied and unoccupied spaces, but it is not possible at present to use this information as a conclusive, index of the potential health hazard of a given environment. The reported number of airborne organisms may vary from 1 to 1000 per cubic foot of air, influenced some what by the method of testing 32. Many are attached to the dust particles which are also present in the air. Where it seems advisable or desirable to control the bacterial content of rooms, public conveyances or buildings, highly effective methods are available (see Chapter 13), and their extended use may do much to assist the workers in this field imaccumulating the necessary mass of evidence that will decide the practical value of air sterilization for the control of communicable disease. It is now well established that ultraviolet radia tion is commercially feasible for the protection or preservation of phar maceuticals, cosmetics, and food products. REFERENCES 1-- Atmospheric Pollution of American Cities for the Years 1931 to 1933, J. E. Ives et al (U. 5. Public Health Service Bulletin No. 224, March 1936). 2- Micromcritics1 The Technology of Fine Particles, by J. M. DaliaValle (Pitman Publishing Cor poration, 1943). s _ Atmospheric Pollution D ue to Smoke, by A. C. Stern (Healing and Ventilating, May. 1945). Atmospheric Pollution Due to Dust and Cinders, by A. C. Stern (Heating and Ventilating, July, 1945). 4--Soot fa11 Studies for New York City, by J. Siegel and B. Felner (A.S.H.V.E. J ournal Section. Heating, P ilin g and A ir Conditioning, September, 1045, p. 495). *--T he Use of Fuel Consumption and Equipm ent D ata in the Abatem ent of Atmospheric Pollution, by A. C. Stern (A.S.H.V.E. J ournal Section, Heating. P ilin g and A ir Conditioning. August, 1945, p. 447-454). 6--Effects of Atmospheric Pollution Upon Incidence of Solar Ultra-Violet Light, by J. H. Shrader. M. H. Coblentz and F. A. Korff (American Journal of Public Heallh, Vol. 19, 1029, p. 7). 7~Studies in Illumination-- I lf : A Study of the Loss of Light D ue to Smoke on M anhattan Island, by J. E. Ives (U. S. Public Health Service Bulletin No. 197. June. 1930). s _ Study and Control of Industrial Atmospheric Pollution Nuisances, by F. M. Stead (American Journal of Public Health, Vol. 35, May. 1945, p. 491-498). ^-E valuation of Odor Nuisance in the M anufacture of Kraft Paper, by J. M. DaliaValle and H. C. Dudley (U. S. Public Health Service Reprint No. 2022. Public Health Reports, Vol. 54, January 13. 1939, p. 35-43). lfl--Disposal of Refinery W astes, Section II: W aste Gases, Vapors, Sludges and Dusta (American Petroleum institute. New York City, 1938). 1 Offensive Trades, by David Ronald (William Hodge and Co., London). 12~Lim its of Inflammability of Gases and Vapors, by H. F. Coward and G. W. Jones ( U. S . Bureau of Mines. Bulletin No. 279, 1939). 13~Inflam m ation Limits and Their Practical Application in Hazardous Industrial Operations, by G. W. Jones (Chemical Reviews, Vol. 22. February. 1938). 1-P riv ate Communication, by Hylton R. Brown (Bureau of Mines, College Park, M aryland). ,fl--Exploalbllity of Agricultural and other D usts as Indicated by Maximum Pressure and R ates of Pressure Rise, by P. W. Edwards and L. R. Leinbach (U. S. Department of Agriculture Technical Bulletin No. 490, October, 1935). i s--D ust Explosion Hazards in Plants Producing or Handling Aluminum, Magnesium, or Zinc Powder, by H. R. Brown (U. S . Bureau o f Mines Information Circular No. 7148. March, 1941). ,7 --Inflammability and Explosibility of Metal Powders, by I. H artm an, J. Nagy and H. R. Brown (U. S. Bureau of Mines RePorl o f Investigation No. 3722, October, 1943). 1fl--Inflammability and Explosibility of Powders Used in the Plastics Industry, by I. H artm an and J. Nagy ( U. S. Bureau o f Mines Report of Investigation Na. 3751, M ay, 1944). l s~Industrial Dust Explosions, by H. R. Brown (U. S. Bureau of Mines, Information Circular No. 7309, January. 1045). A ir C ontam inants 179 2fl-Froposed Code for the Prevention of Dust Explosions in the Plastics Industry (National Fire Protection Association, Boston, May, 1945). *--National Fire Codes for the Prevention of Dust Explosions (National Fire Protection Association, Boston, 1944). Contains codes for aluminum, magnesium, coal, pulverized fuel, flour, spice, starch, sugar, cocoa, sulfur and wood. - A n Introduction to Pollen Analysis, by G. Erdtman (Chronica Botanica Co., Waltham, M ^s, 3943). 2 3 -- Pollen Grains, by R. P. Wodehouse (McGraw Hill Book Co., New York, 1935). 24" Atmospheric Pollen, by R. P. Wodehouse (Aerobiology, p. 8-31, Publication No. 17, American Association for the Advancement of Science, Washington, D.C., 1942). 2S-Hayfever Plants, by R. P. Wodehouse (Chronica Botanica Co., Waltham. Mass., 1045). 2fi-H ay Fever: A Geographical and Botanical Survey, by E, R. Squibb and Sons, New York, 1037. 27- Techmquea for Appraising Air-Borne Populations of Microorganisms, Pollen and Insects (Phyto pathology, Vol. 31, March. 1041, p. 201-225), 28-- Apparatus for Determining the Pollen Concentration of the Atmosphere, by B. J. Cody, W. F. Kinney and N. A. Kerstein (Research Department, the Detroit Edison Company.JDetroit). 2-The Volumetric Incidence of Atmospheric Allergens, by O. C. Durham (Journal of Allergy, Vol. 14, Septem ber 1943, p. 455-461). ao--The Volumetric Incidence of Atmospheric Allergens, II: Simultaneous Measurements by Volumetric and Gravity Slide Methods, by O. C. Durham (Journal of Allergy, Vol. 15, May, 1944, p. 226-235). a l_ Air-Borne Fungus Spores as Allergens, O. C. Durham (Aerobiology, p, 32-47, Publication No. 17, American Association for the Advancement of Science, Washington, D. C., 1942). 3Z--Sampling Devices, by H. G. DuBuy and A. Hollaender (American Journal of Medical Science, Vol. 209, February, 1045, p. 172-177). BIBLIOGRAPHY Abstracts and Bulletins (monthly, annual and special) Industrial Hygiene Founda tion, Inc., Pittsburgh, Pa. Aerobiology, Publication No. 17 (American Association for the Advancement of Sci ence, Washington, D. C.f 1942). Air Sanitation and Industrial Ventilation, by W. N. Witheridge (Detroit, Mich., 1945). Analytical Chemistry of Industrial Poisons, Hazards and Solvents, by M. B, Jacobs (Interscience Publishers, New Y.ork, 1941). , Bibliography of Industrial Hygiene,,1900-1943 (U. S, Public Health Service Bul letin No. 289, 1945). Clouds and Smokes, by W. E. Gibbs (P. Blakiston's Son & Co., Philadelphia, Pa,, 1924). Determination and Control of Industrial Dust, by Bloomfield and DallaValle (U. S. Public Health Service Bulletin No. 217, 1935). Dust, by S. C. Blacktin (The Sherwood Press, Cleveland, 1934). (The) Environment and Its Effect upon Man (Harvard School of Public Health, Boston, 1937). Industrial Dust, by Drinker and Hatch (McGraw Hill Book Co., New York, 1936). Journal of Industrial Hygiene and Toxicology (monthly) (Harvard School of Public Health, Boston, Mass.). See cumulative abstract and subject indexes. Manual of Industrial Hygiene, by W. M. Gafafer et al (i7. S; Public Health Service, W. B. Saunders Co., Philadelphia, 1943). Noxious Gases and the Principles of Respiration Influencing their Action, by Hender son and Haggard (American Chemical Society Monograph Senes No, 35, Reinhold, New York, 1943). Occupation and Health, two volumes (International Labor Office, Washington, D. C.). Toxicology and Hygiene of Industrial Solvents, by Lehmann and Flury, translated by Eleanor King and H. F. Smyth, Jr. (Williams and Wilkins, Baltimore, 1943). A ir Conditioning U n if H eaters nnd Coalers The TRflfiE Company 2021 Cameron Avenue, Ta C rosse, W isconsin COMPLETE LINE OF HEATING, COOLING, AIR CONDITIONING AND AIR HANDLING EQUIPMENT Over 70 U. S. B ra n c h Offices A lbany. N ew York Albuquerque, N .M , Allentown, Pa. Amarillo, T exas Appleton. W is. Atlanta, Georgia Aurora. I llinois Baltimore, Md. B illings, Montana Birmingham, Aladama Boston. M ass. Buffalo. K. Y. Canton, O hio Chattanooga. T enn. Chicaco, I llinois C incinnati. Ohio Clarksburg, W. Va. Clarksville. T enn. Cleveland, Ohio Columbus, Ohio D allas, T exas D avenport, Iowa D ayton, Ohio D enver, Colorado D es Moines, Iowa D etroit, M ich. F lint, M ichigan Gainesville, F la. G rand R apids. M ich. Greensboro, N /C . G reenville, S. CH arRisdurg. P a. Houston, T exas I ndianapolis. Ind. K ansas C ity, M o. 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Long years of experience with practical knowledge gained from close field contact, have developed products for every requirement. T ra n e S y stem s--So com prehensive is the Trane Line th at any number of complete heating and air conditioning system s can be designed in which all the major parts are made by Trane. Examples: Trane Custom-Air System of Air Conditioning for multipleroom buildings; central and unit systems of air conditioning for com fort and processes; steam and hot water heating system s. P roducts used in these systems are designed and made together for use together. Undivided responsibility. T rane C onvector-radi a to r --The modern successor to Lhe old-fashioned radiator, the Trane Convector-radiator is a compact, light-weight, easy-toinstall unit. Available for either steam or hot water heat ing system. It combines attrac tive appearance with long life and economical service. 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Write today for Trane Condensed Catalog PB290 which describes completely all of the products listed here as well as providing sufficient data for their selection. Healing Systems Pumps BIRMINGHAM BOSTON BUFFALO BUTTE CHICAGO CLEVELAND I n g e n r o ll- R a n d II BROADWAY. NEW YORK A. N Y. DALLAS DENVER DETROIT DULUTII EL PASO KNOXVILLE LOS ANGELES NEWARK NEW ORLEANS NEW YORK PHILADELPHIA RICHER PITTSBURGH SALT LAKE CITY SAN l-RANCISCO Offices and agents throughout the world SCRANTON SEATTLE ST. LOUIS TULSA W A SH IN G T O N CENTRIFUGAL PUMPS T h e - - ! VK ' ^ is a c o m p a c t , " package" unit, mounted integrally with motor on a rigid, oversize shaft and over size bearings. It is highly adaptable to many services, needs no special foundation, and operates equally well in any position. It is available in several materials for pumping various liquids. Capacities from 10 to 1800 gpm, heads to 600 ft. Other I-R pumps are offered for all hydraulic services, with any type of drive. ALL PURPOSE PORTABLE TOOL The 4U Electric Im pact Tool is a light weight, portable, tool for running and re moving nuts, screws and studs, drilling, reaming, tapping, wire brushing, drilling brick and masonry, driving wood augers, hole-saw work, and the 101 jobs en countered in installation work. Plugs into any wall outlet. Capacities: % in. drills, step-reaming to in., running nuts to % in. thread size. 110 and 220 volts, 25 to 60 cycles universal motor. LIGHT-W EIGHT JACKHAMER 'The J-10 Jackhamer is the smallest of the self-rotating, rock-drill line, weighs 14 lbs. and is especially designed for maintenance and installation work. Its uses include drilling masonry for conduit, sprinkler hangers, foundation bolt holes, pipelines and drains as well as tearing out brick work for doors and windows and similar demolition jobs. The J-10 is air-powered. STEAM-JET REFRIGERATION Where refrigeration is needed down to 35F ( and a supply of steam is available, the I-R system of water-vapor refrigeration with Steam-Jet Coolers is offered. In this system water is the only refrigeration medium. It is cooled by direct evapora tion in a high vacuum created by steam -jet booster ejectors. There are no moving parts, no vibration nor noise. Sizes run from 20 to 1200 tons of refrigeration and can be built to operate at any one of a wide range of pressures down to 2 lb per sq in. I-R COMPRESSORS OF ALL TYPES AND SIZES 1-R Compressors are offered in all sizes and types from to 3000 hp /in pressures from a few ounces to 15000 lbs, and in stationary or portable models. Air-cooled units range from y<>to 90 hp. I-R W ater systems are available for industrial and domestic uses. 1204 108 H e a tin g V e n tila tin g A ir C o n d itio n in g G u id e 1948 T O W N E . R o b in M . (J 1945) Aset. Engr., R ichard M . S tern , Cona. E ngr., 1331 T h ird A ve., Bldg., S e a ttle 1, an d 4020 E a st 135th S t., S e a ttle 55, W ash. T O W N E R , C h a r le s E . (A 1944) T e stin g E n g r., C rane Co., 830 S. M ichigan Ave., Chicago, and 9141 S. M ayfield, O ak L aw n, 111. T O W N S E N D , J o h n M . (Ai 1942) Sales E ngr.. Serve] Inc., 122 S. M ichigan A ve., C hicago, a n d 6138 K im b a rk , C h ic a g o 37, 111. T R A C Y , J o h n W . ( M 1945) Sales E ngr., M inne apolis-Honeywell R egulator Co., 415 B rainard S t.. D e tro it 1, an d 18687 P e n n in g to n D r., D etroit 21, M ich. T R A C Y , W illiam E. (A 1943; J 1938) 006 N . A u stin B lvd., O ak P a rk , 111. TR A M B A U ER , C h arles W . {M 1945; A 1941; J 1936) Sates M gr.. H erm an N elson Corp., 424 Book Bldg., D etro it 26, and 9262 P iedm ont, D etroit, Mich. T R A N E , R e u b e n N.* (M 1915) Pres.. T h e T ran e Co., and 208 South lfith St., LaCrosse. Wig. T R A U G O T T , M o rtim e r (A 1930) B ryant Air Conditioning Corn.. 915 N. F ro n t S t., P hila delphia 23, and 8208 W estm inster Rd., Elkins Park, Pa. T R A U T M A N , F red L. (M 1944) Owner, T ra u t- m an Engineering Co., 1122 E ast 17th Ave., D enver, Colo. T R A Y N O R , H a rry S. (A 1942; J 1937) M gr.. R egent K n ittin g Co.. 219 W ashington Sq., Syracuse, and 137 Edw ards D r.. Fayetteville, K Y. T R A Y N O R , J o h n H . (Af 1946) Sales Engr.. Jo h n so n Service Co., 1031 W y an d o tte St.. K a n sa s C ity 6, a n d 232 R ain b o w L ane, K a n sa s City, Mo. TR EA D W A Y , J . Q u e n tin (A 1936; J 1932) D ist. Sales M gr., O a ra g e F a n Co.. 706 R eynolds Arcade, and 826 W inona Blvd., Rochester. N . Y. T R E F T S , J o h n C ,, J r . (M 1944) Vice-Fres. and G en. Sales M g r.. F a r r a r & T re fts. In c .. 20 M ilburn St., Buffalo 12, and E ast Q uaker Rd., O rchard Park, N . Y. T R E L E A V E N . H . M . (A 1946) M gr., A ir Cond. D ept., T rane Com pany of C anada, L td., 4 M ow at Ave., T oronto, O nt., C anada. T R E N IIA IL E , D ale T. (J 1945) M ech. Engr.. Ind. Design, V ent., H tg., Refrie. & A ir Cond. G. R. P., Ind. Design Br., N av. Shipyard. Pearl H arbor, and 2188 Hernm oa Rd.. H onolulu 20, T . H. T R I C K E Y , G e o rg e (A 19451 Sales E n g r., P ease F o u n d ry Co., L td .. 227 V ictoria S t., and 97 Oakwood Ave., T oronto. O nt., C anada. T R IC K L E R , E arl E . (M 1942) Chief E ngr., New Y ork Blower Co., 32nd an d Shields, and 8219 K enw ood A ve., C hicago 19, 111. T R IE G E L . E ric h V. ( M 1942) M ech. E ngr., F ran cisco 8c Jaco b u s, f ill F ifth A ve., N ew Y o rk , N . Y., an d * R . F . D . 3, D an b u ry , Conn. T R IG G S . F re d E . ( M 1938) F acto ry R cpr., 215 P lym outh Bldg.. D es M oines 9, and 3901 Second A ve., D es M oines 13. Ia. T R I M B L E , C la rk e R . ( M 194G) P re s. & T re a s., C. R . T rim ble Co., Inc., P. O. Box 6066, and 205 C ottage PI., C harlotte 7. N . C. T R IM B L E , J o h n I. (Af 1945) M gr., Ja n itro l Engrg., Surface Com bustion Corp.. 400 D ublin Ave.. Columbus, and a 2038 Bedford R d., Colum bus 8. Ohio. T R IT L E , H a ro ld J . (A 1940) Sales M gr.. S . T. Carlson Co., P. O. Box 901, and 1114-37th, Des Moines, Ia. T R O D D , _ E d w a r d R . (A 1946) A sst. E n g r.. .C anadian Pacific R ailw ay Co.. Room 401, W indsor Station, M ontreal, and 848 W olseley Ave.. C ote St. Luc., Que., C anada. T R O L L E R , T . H .* ( M 1943) Vice-Pres., Charge of E n g rg ., Jo y M anufacturing Co., 333 O liver Bldg., P ittsburgh 22, P a., and 1250 Sunsetvicw D r., A k ro n 2, O hio. T R O S T E L , O tto A. (Af 1935) E ngr., S ta n d a rd D istrib u tin g Co., 406 E. W ells S t.. M ilw aukee 2, a n d R t. 2, Thienaville, Wis. T R O U P , J o h n D . (M 1938) M anaging Dir., John D . Troup. L td ., 90 High H olborn. London, W . C. 1, and 48 Plough Lane, Purley, Surrey, E n g lan d . T R O W B R ID G E , C a rl Y . (A 1944) Secy.-T reaa. and Gen. M gr., R a y F . Fischer Go., 323 N .W . T e n th St., O klahom a C ity 3, and 3420 N o rth w est 25th St., O klahom a C ity, Okla. ' T R U C H O N , L o u is P . (A 1947) Sales E ngr. & D raughtsm an, T ran e C om pany of C anada, Ltd., 926 Price Bldg., and 429 S t. V allier S t., Quebec C ity, Quc., C anada. T R U M B O , S. M . (A 1926) Sales, B uffalo F orge Co., 20 N . W acker D r., Chicago 6, and 921 F ran k lin St., D ow ners G rove, 111. T U C K , R o b e rt G . (A 1946) E ngr., In tern atio n al Sales Co., 2045 E v an s Ave., San Francisco, and 1001 San R aym undo Rd., H illsborough, Calif. T U C K E R , F r a n k N . fM 1926) F ield Engr.. l l g E lectric V entilating Co., C raw ford Ave., Chicago, 111., an d 2 3 9 W h aley St., F re e p o rt, L . L , N . Y. T U C K E R , J . R o b e r t (A 1945) E n g r., C om m ercial T esting, U nited S tates T esting Co., Inc., 1415 P ark Ave., Hoboken, and 86 Bergen Ave., Teaneck, N. J. T U C K E R , L e o n a rd A. (M 1935) Service M gr., J . J. Pocock, Inc., 1020 C hestnut St., Philadelphia 3. and 220 Buttonw ood W ay, Glenside, Pa. T U C K E R , R a lp h E. (M 1947) Bldg. Supt.. Foley Bros., 407 M ain S t., Box 1971, H ouston, and 228 S an ta Fe D r., H ouston 12, T exas. T U C K E R , S y d n ey ( M 1945) Chief Engr., F itz - gibbona Boiler Co., Inc., and 247 W . Sixth St., Oswego, N . Y. T U C K E R , T h o m a s T . (M 1938; A 1936) Chief Engr., A rm or Insulating Co., 1102 C andler Bldg., and 800 Forrest St. N.W ., A tlanta, Ga. TUCKERM AN, G eorge E. 1032) Special Repr., Air Cond. and Refrig. D iv., W orthington P u m p fit M ach in ery C orp., 2905 N . B road S t.. P hiladelphia 32, and 20 M eridlth R d., Green Hill Farm s, M erlon, Pa. T U F F L Y , H a rry J . (5 1946) S tudent, Texas A. Sc M . College, B ox 5605, College S ta tio n , and 715 Skillm an St., Dallas, Texas. T U IT E , J a m e s M . (A 1947) A sst. M gr., B. P. T u ite Co., Oneida, and 1156 T aylor Ave., U tica, N. Y. T U N Z IN I, B e rn a rd (M 1947) M gr.. Etablisse- m en ts T unzini: 69 R ue L egendre, and 1 2 6 Q uai Louis Blriot, Paris 16, France. T U P P E R , E d w a r d B . (A 1948; J 1944; 5 1941) R efrigerative Supply. 2211 F ifth Ave.. and 623134th N .E ., S eattle 6, W ash. T U R L A N D , C h a r le s H e n r y (Ai 1934; A 1930) Engr., R. E. Johnston Co.. Ltd., 3070 Homer St., and 4553 W. Third Ave.. Vancouver, B. C., Canada. T U R N B U L L , E r n e s t R . (A 1948) D esigner, K arel R. Rybka, C ons. E n g r.. 96 B loor S t. W. and 211 St. G erm ain Ave.. T oronto. O nt.. C anada. T U R N B U L L , F ra n c is J . (M 1945) Engr., Fay Spofford & T h o rn d ik e, 11 B eacon S t., B oston, and 625 P leasant St., M ilton 86, M ass. T U R N E R , E d m o n d S . (A 1939) P a rtn e r, W il liam S. T u rn er & Co., 432 Pacific Bldg., P ortland 4, an d 3455 N o rth east 36th A ve., P o rtla n d 13, Ore. T U R N E R , G e o rg e G . (A 1945) W e ste rn M g r., H eating & V entilating M agazine, 228 N . L aS alle St., C hicago 1, a n d 827 H in m a n A ve., E v a n sto n , HI. T U R N E R , G eorge W . (M 1944) M gr., G eorge B. M allory Co., 1436 B lackstone A ve., and 203 Shields. Fresno, Calif. T U R N E R , J o h n F. (M 1947; A 1946) Asst, to P ro je c t E n g r., M onsanto C hem ical Co., an d 142 Georgia Ave., O ak Ridge, T enn. T U R N E R , J o h n P ,, J r . (M 1942) Field Sales M gr.. Air Cond. D ept,, G eneral:Electric Co., 5 Law rence St.. Bloomfield, and 727 M osswood Ave., Orange, N. J. T U R N E R , W il li a m M . (A 1945) S upvar. E ngr.. T he R ipstra Co., 1016 E. Douglas, and 4802 E. English, W ichita, K ans. T U R N O , W a lte r G. W . ( I f 1917; A 1912) Secy., H . W . P orter & Co., N ew ark, an d *71 L afayette Ave., E ast O range, N . J. T U S C H , W a lte r (M 1917) R etired. 881 Sterling PL, Brooklyn 16. N . Y. T U T H IL L , A r t h u r F . (A 1947; J 1940; S 1938) A sst. Prof., D ep t, of M ech. E n g rg ., U n iv e rs ity of V erm ont, B urlington, and 78 E . F o rt E th a n Allen, W inooski, Vt. -- T U T S C H , R o d n e y J . (A 1943; J 1939) Sales & Appl. Engr., Cleaver-Brooks Co.. 326 E . Keefe Ave.j M ilw aukee 12, and 4455 N . O akland Ave., M ilwaukee, Wis. T U T T , R ic h a rd D. (M 1946; J 1942) C hief Engr., T u ttle & Bailey, Inc., and 99 Sylvan R d., New Britain, Conn.