Hazardous Classifications

Class I

Areas in which flammable gases or vapors may be present in the air in sufficient quantities to be explosive

Group A: Atmospheres containing acetylene
Group B: Atmospheres such as butadiene, ethylene oxide, acrolein or hydrogen (or gases or vapors equivalent in hazard to hydrogen, such as manufactured gas)
Group C: Atmospheres such as cyclopropane, ethyl ether, ethylene or gases or vapors of equivalent hazard
Group D: Atmospheres such as acetone, alcohol, ammonia, benzene, benzol, butane, gasoline, hexane, lacquer solvent vapors, naphtha, natural gas, propane or gases or vapors of equivalent hazard

Class II

Areas made hazardous by the presence of combustible dust.

Group E: Atmospheres containing combustible: 1 - Metal dusts, regardless of resistivity 2 - Dusts with similarly hazardous characteristics having a resistivity of less than 100 κΩ-cm 3 - Electrically conductive dusts
Group F: Atmospheres containing combustible:
1 - carbon black, charcoal or coke dusts having more than 8% total volatile material 2 - dusts so sensitized that they present an explosion hazard, and having a resistivity greater than 100 Ω-cm but less than or equal to 1 x 10⁸Ω-cm
Group G: Atmospheres containing combustible:
1 - dust having resistivity equal to or greater than 100 κΩ -cm
2 - electrically non-conductive dusts

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