CLASS I - HAZARDOUS LOCATIONS
Refers to locations where flammable gases or vapors are present in the air, with quantities sufficient to form explosive or ignitable mixtures.
Divisions
Division I: Locations where hazardous concentrations in the air exist continuously, intermittently, or periodically under normal operating conditions.
Division II: Locations where hazardous concentrations are encountered during the handling, processing, or usage, but are typically contained within closed systems or containers, escaping only in the event of accidental rupture or breakdown.
Groups
Group A: Atmospheres containing acetylene.
Group B: Atmospheres containing hydrogen, or gases/vapors of equivalent hazard (excluding Division 1 design).
Group C: Atmospheres containing ethyl-ether vapors, ethylene, or cyclopropane.
Group D: Atmospheres containing gasoline, hexane, naphtha, benzene, butane, alcohol, acetone, benzol, lacquer solvent vapors, or natural gas.
CLASS II – HAZARDOUS LOCATIONS
Designates locations that pose a hazard due to the presence of combustible dust in the air.
Divisions
Division I: Locations with continuously, intermittently, or periodically hazardous concentrations under normal operating conditions.
Division II: Locations where hazardous concentrations are confined within closed systems or containers, escaping only in case of accidental rupture or breakdown.
Groups
Group E: Atmospheres containing metal dust, including aluminum, magnesium, and their commercial alloys, and other metals with similar hazardous characteristics.
Group F: Atmospheres containing carbon black, coal, or coke dust.
Group G: Atmospheres containing flour, starch, or grain dust.
