Document MyDgaYEreMdGJrZZBV5y8a8j

Table 6. Approximate Limits of Flammability of Single Gases and Vapors In Air at Ordinary Temperatures and Pressures* Gas ob Vapob Lowrr Limit Percent bt Volume Uppeb-Limit Percent bt Volume Closed Cupb NBFU Aeetyldehyde. Acetone.......... Acetylene...... . Allyl alcohol.. Ammonia....... Amyl alcohol....... Amyl chloride . ... Amylene............... Benzene (benzol). Benzyl chloride ... Butane................. . Butyl acetate....... Butyl alcohol........ Butylene.............. Carbon disulfide... Carbon monoxide. Crotonaldehyde... Cyclohexane........ Cyclopropane....... Decane................. Dichloroethylene (1, 2) . Diethyl selenide............ Dioxane......................... 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 (variable) . Heptane.................. Hexane.................... Hydrogen cyanide.. Hydrogen............................ Hydrogen sulfide............... Illuminating gas (coal gas). Isobutyl alcohol................. Isopentane.......................... Isopropyl acetate. Isopropyl alcohol. Methane............... Methyl acetate.... Methyl alcohol-- Methyl bromide......... Methyl butyl ketone. Methyl chloride........ Methyl cyclohexane.. Methyl ethyl ether-- Methyl ethyl ketone... Methyl formate........... Methyl propyl ketone.. Natural gas (variable) . Naphtha (benzene)---- Naphthalene. Nonane______ Octane.......... Paraldehyde. Pentane........ 4.0 2.5 2.5 2.5 15.5 1.2 1.6 1.6 1.3 1.1 1.8 1.4 1.7 2.0 1.2 12.5 2.1 1.3 2.4 0.67 9.7 2.5 2.0 3.1 1.8 2.2 3.3 6.7 2.6 4.0 2.7 6.2 2.7 3.0 3.0 2.1 1.4-1.5 1.0 1.2 5.6 4.0 4.3 5.3 1.7 1.3 1.8 2.0 6.0 3.1 6.7 13.5 1.2 8.2 1.1 2.0 1.8 5.0 1.5 4.3 1.1 0.9 0.83 0.95 1.3 1.4 57 12.8 8.4 15.0 (L7 50 74.2 15.5 8.4 10.5 2.6 12.8 22^2 12.5 36.5 11.5 19.0 11.3 15.7 14.8 28.6 15.9 16.5 50 6.0 6.9 40.0 74.2 45.5 33.0 7.8 i5lo 15.5 36.5 14.5 8.0 18.7 ioli 9.5 22.7 8.2 13.5 6.0 2^9 3.2 'l. 8 0 ?' 70 II & III 12 I 140 III 115 57 "54 -49 28 54 104 -58 56 -4 -31 140 -50 25 -15 II I III II II 1 II II HI I II I .I III I II I 43 53 14 52 "25 -35 30 -2 20-lio 176 88 56 II n i n U I II I III III III II 3 Air Contaminants 165 Table 6. Approximate Limits of Flammability of Single Gases and Vapors In Air at Ordinary Temperatures and Pressures* (Concluded) Gas ob Vapob Lo eb Limit Percent bt Volume Upper Limit Pebcent bt Volume Closed Cupb Flash Point Fahrenheit NBFU CLASSIFI CATION0 Propane............................... Propyl acetate..................... Propyl alcohol..................... Propylene............................. Propylene dichloride........... Propylene oxide................... Pyridine............................... Toluene (toluol).................. Turpentine........................... Vinyl ether.......................... Vinyl chloride...................... Water gas (variable)............ Xylene (xylol)...................... 2.1 1.8 2.1 2.0 3.4 2.0 1.8 1.3 0.8 1.7 4.0 6.0 1.0 10.1 8.0 13.5 11.1 14.5 22:0 12.4 7.0 27.6 21.7 70 6.0 58 II 59 II 60 H 74 III 40 -II 95 III 63 II * Adapted from: Fire and Explosion Hazards of Combustible Gases and Vapors, by G. W. Jones; Chapter 13, Industrial Hygiene and Toxicology, edited by F. A. Patty (Interscience Publishers, 1948); Properties of Flammable Liquids, Gases and Solids (Associated) Factory Mutual Fire Ins. Cos., January (1940); and National Fire Codes for Flammable Liquids, Gases, Chemicals and Explosives--1945 (National Fire Protec tion Association). b Closed cup refers to the equipment used in flash point determinations. "From Standards for Storage, Handling and Use of Flammable Liquids (National Board of Fire Un derun-iters, No. 30, July 1954). and reporting methods of the laboratory. Translation of gravity counts by special formulas to a volumetric basis, or the number of grains per cubic yard or per cubic foot of air, is unreliable because of the complexity of the modifying factors. When such information is important, it is best obtained directly by a volumetric instrument. The number of pollen grains per cubic yard of air evidently varies from 2 to 20 times the number found on 1 sq cm of a 24-hr gravity slide, depending on grain diameter, shape, specific gravity, wind velocity, humidity and physical placement of the collecting plate.29 , 30 31 AIRBORNE BACTERIA Study of the occurrence and significance of micro-organisms in the at mospheres of the indoor world is absorbing the energies of a substantial number of physicians, bacteriologists, aerobiologists, physicists, public health workers, engineers and hospital personnel. Some data are available on the types and quantities of bacteria found in a variety of spaces, but it is not possible at present to use this information as a conclusive index of the potential health hazard of a given environment. The reported number of airborne organisms may vary from 1 to 1000 per cubic foot of air, influ enced somewhat by the method of testing.32 Many are attached to the dust particles present in the air. Where it seems advisable or desirable to control the bacterial content of rooms, public conveyances or buildings, highly effective methods are available (see Chapter 7), and their extended use may do. much to assist the workers in this field in accumulating the necessary mass of evidence that will decide the practical value of air sterilization for the control of communicable disease. It is now well established that ultraviolet radia tion is feasible for the protection or preservation of pharmaceuticals, cos metics, and food products. RADIOACTIVE AIR CONTAMINANTS33 Radioactive air contaminants are physically similar to ordinary indus trial and chemical plant contaminants. They differ from ordinary con-