User Guide

CLASSIFICATION OF HAZARDOUS ATMOSPHERES
Class Division Group Typical atmosphere/ignition temps.
I 1 A acetylene (305C. 581F)
Gases, Normally
vapors hazardous B butadiene
1
(420C. 788F)
ethylene oxide
2
(429C. 804F)
hydrogen (520C. 968F)
manufactured gases containing more than 30% hydrogen
(by volume)
Propylene oxide
2
(449C. 840F)
C Acetaldehyde (175C 347F)
cyclopropane (503C. 938F)
diethyl ether (160C. 320F)
ethylene (450C. 842F)
unsymmetrical dimethyl hydrazine (UDMH) (249C. 480F)
D acetone (465C. 869F)
acrylonitrite (481C. 898F)
ammonia
3
(498C. 928F)
benzene (498C. 928F)
butane (288C. 550F)
1-butanol (343C. 650F)
2-butanol (405C. 761F)
n-butyl acetate (421C. 790F)
ethane (472C. 882F)
ethanol (363C. 685F)
ethyl acetate (427C. 800F)
ethylene dichloride (413C. 775F)
gasoline (280-471C. 536-880F)
heptane (204C. 399F)
hexane (225C. 437F)
isoamyl alcohol (350C. 662F)
isoprene (220C. 428F)
methane (630C. 999F)
methanol (385C. 725F)
methyl ethyl ketone (404C. 759F)
methyl isobutyl ketone (440C. 840F)
2-methyl-1-propanol (416C. 780F)
2-methyl-2-propanol (478C. 892F)
naptha (petroleum)
4
(288C. 550F)
octane (206C. 403F)
pentane (243C. 470F)
1-pentanol (300C. 572F)
propane (450C. 842F)
1-propanol (413C. 775F)
2-propanol (399C. 750F)
propylene (455C. 851F)
styrene (490C. 914F)
toluene (480C. 896F)
vinyl acetate (402C. 756F)
vinyl chloride (472C. 882F)
xylenes (464-529C. 867-984F)
2 A Same as Division 1
Not B Same as Division 1
normally C Same as Division 1
hazardous D Same as Division 1
II 1 E Atmospheres containing combustible
Combustible Normally metal dusts regardless of resistivity, or
dusts hazardous other combustible dusts of similarly hazardous
characteristics having resistivity of less than 10
5
ohm-
centimeter
F Atmospheres containing carbonaceous dusts having
resistivity between 10
2
and 10
8
ohm-centimeter
G Atmospheres containing combustible dusts having
resistivity of 10
5
ohm-centimeter or greater
2 F Atmospheres containing carbonaceous
Not normally dusts having resistivity of 10
5
hazardous ohm-centimeter or greater
G Same as Division 1
III 1 & 2
Easily ignitible
fibers and
flyings
3