Class I

Gases of Vapors

Division I = Normal Operation (Hazardous vapors present)

Division II = Abnormal Operation (Hazardous vapors contained, but may be present)

Groups

• A = Acetylene
• B = Hydrogen + others  (specifics)
• C = Ethyl Ether, Carbon Monoxide, + others   (specifics)
• D = Butane, Methane + others  (specifics)