Unformatted text preview: UNDERWRITERS’ LABORATORIES’ CLASSIFICATION OF COMPARATIVE Group Between 4
and 5 5:: Sb LIFEHAZARD 0F GASES AND VAPORS
(Group number deﬁnition} Dellnilion Cases or vapors which in concentrnl'tom of the order of '32 lo 1‘3: for durations of exposure of the
order of 5 min are lelha! or product: serious injury. Gases or vapors which in concentrations of the order of It; lo M for duration efexposure of the
order of 'I; h are lethal or produce serious injury Gases or vapors which in oonoenlat'ions of the order of 2 lo Z'Jg'li for durations ofeirposure of the
order of I hr are lethal or produce serious injury. Gases 0r vapors which in eonoemratioins of the order of 2 to Z'lgﬁi for durations of exposure of the
order of 2 h are lethal or produce seirous injuryI
Appear to classify as somewhat! less toxic than Group 4. Much less toxic than group 4 but somewhat more toxic than Group 5. Gases or vapors much less toxic than Group 4 bul more toxic than Group 6. Gases or vapors which available data indicate would classify as either Group 551 or Group 6.
Gases or vapors which in concentralions up to at least about 20% by volume for duration of expo-
sure of the order of 2 h do not appear to produce injury. ‘ Not Iesled by U.L. but estimated to belong in group indicated. Examples
Ammonia. methyl bromide anmchlommelhane carbon
Methylene chloride. ethyl
Ethane. propane. butane
Refrigerant C3 IS‘ ...
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- Fall '10