Document rBDrqxvmZpwL9pjJwz8x9ZXwv

Heating Ventilating Air Conditioning Guide 1939 violent air motion will sustain them in air long enough for them to be breathed. This means that, in hygienic problems, the engineer is con cerned mostly with suspensions of particles comparable to the common Compiled by W. G. Frank and Copyrighted. Fig. 1. Sizes and Characteristics of Air-Borne Solids bacteria in size. A notable exception to this size limitation is the common hay-fever producing pollen such as that from rag-weed. Pollen grains may be anything from fragments 15 microns in diameter to whole pollens 25 microns or more in size. Since the lower limit of visability to the 78 Chapter 4. Air Pollution Table 1 Approximate Limits of Inflammability of Single Gases and Vapors in Air at Ordinary Temperatures and Pressures3 Gas or Vapor Lower Lncrr Volume in Per Cent Higher Limit Volume in Per Cent Hydrogen.........-......................... Ammonia............... -.................. Hydrogen sulphide...--............ Carbon disulphide................... Carbon monoxide.....-.............. Methane................................. Methane (turbulent mixture) Ethane........................................ Propane....... ............................... Butane.--~.................................. Pentane-..........................-........... Ethylene....................................... Acetylene...................................... Acetylene (turbulent mixture) Benzene.--......................... ........ Toluene....................-.... ...... Cyclohexane......................... Methyl cyclohexane.......... -- Methyl alcohol.--................. Ethyl alcohol........... ............ Ethyl ether............ ..... ........ Benzine.............. ---..... -....... Gasoline................................ Water gas.............. ............... Ethylene oxide....... ..... ........ Acetaldehyde........................ Furfural (125 C).................. Acetone............................. . Acetone (turbulent mixture). Methyl ethyl ketone............. Methyl formate..... Ethyl formate.... ... Methyl acetate.__ Ethyl acetate........ Propyl acetate....... Butyl acetate (30 C)..._ Ethyl nitrite....... .......... Methyl chloride............ Methyl bromide... ........ Ethyl chloride.--........... Ethyl bromide.............. Ethylene dichloride___ Dichlorethylene............ Vinyl chloride..... .......... Pyridine (70 C)............ Natural gas.--....... Illuminating gas..... ...... Blast-furnace gas._ 4.1 ' 16.0 4.3 1.0 12.5. 5.3 5.0 3.2 2.4 1.9 1.45 3.0 3.0 2.3 1.4 1.4 1.3 1.2 7.0 4.0 1.7 1.1 1.4 6 to 9 3.0 4.0 2.0 3.0 2.5 2.0 6.0 3.5 4.1 2.5 2.0 1.7 3.0 8.0 13.5 4.0 7.0 6.0 10.0 4.0 1.8 4.8 5.3 35.0 74.0 27.0 46.0 50.0 74.0 14.0 15.0 ' 12.5 9.5 8.5 7.5 29.0 7.0 7.0 8.3 19.0 26.0 6.0 55 to 70 80.0 57.0 iTo 12.0 20.0 16.5 14.0 11.5 19.0 14.5 15.0 11.0 16.0 13.0 22.0 12.5 13.5 31.0 74.0 GaSeS a"d VaPra' by H` R Coward and G- W- Jonea- (U' S' Bureau f 79