Document Qk7Br8ommkodwLwpJqR2ddYg4

510 CAREY P. MC CORD Characteristics C o m m o n E x te rn a l! M a rk s o f O c c u p a tio n o r O c c u p a tio n a l Diseases o r O th e r Diseases (co n clu d e d ) j a om 'JJ 11 i a'E If S 0 I &g'ej > *43-a s 15 *1. 1 ;|SSp lfSieilrs1t.a16l fl^ |,sj is>-gl !** 1 "Oa s &l J "a &0-53 Is a Si8 P ihhl I'S'S s 0:S;. . o S o JlSll-' P541f|r; J , J s |lT| CHAPTER XVI--SECTION ONE ^Band Explosion Hazards of Combustible Gases and Vapors* G. W. JONES and explosions resulting from the presence of combustible gases and |afe among the major hazards in present industrial operations. There is |a?: greater appreciation of these hazards and better understanding of ^mitigating and preventing them. I. Limits of Flammability sion has arisen regarding the meaning of the terms "explosive limits," e,limits," and "limits of flammability." In the final analysis these pressions-mean~the-same~thing,_Some authorities.regard. .explosive limiting mixtures within which flame will propagate through the Hume of the mixture and develop appreciable pressure, while flammable pdmits of flammability, are regarded as those limiting mixtures within mb'.will propagate entirely through the mixture without regard as to pressure is produced. Impossible to distinguish a flammation from an explosion by the amount ||produced. Mixtures just within the limits of flaihmability, if .confined plbe and tested by opening one end and igniting .at this open end, will Eflame quietly and slowly through the tube (usually at a uniform.speed) peed, for a given concentration of combustibles in air, will vary with 'Blpf-flame-propagationi^This^mixture, .if -confih'eii^ih-aielosed^bomb ^dimensions and ignited when the gases are in motion or gentle turbupropagate flame at a speed several times as fast as that in the open develop pressures ranging up to 30 p.s.i. or more. Thus'itJ.is ^se^n that ^^mJ^od.i>y-.a^fla?nmable. mixture depends .upon the..environment of flame propagation; therefore, no differentiation-should, dr caffT" oetween explosive limits and limits of flammability. lithe Central Experiment Station, Bureau of Mines, U. S. Department of the Interior,. SEenna.; revised November 15, 1954. *' t 511 & Mark or]sign