Locations in which flammable gases or vapors are/or may be present in the air in quantities sufficient to produce explosive or ignitable mixtures.

• Division I - Locations in which hazardous concentrations in the air exist continuously, intermittently, or periodically under normal operating conditions.
• Division II - Locations in which hazardous concentrations are handled, processed, or used but are normally within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown

• Group A - Atmospheres containing acetylene.
• Group B - Atmospheres containing hydrogen, or gases or vapors of equivalent hazard, such as manufactured gas. (not available in Division 1 design).
• Group C - Atmospheres containing ethyl-ether vapors, ethylene or cyclo propane.
• Group D - Atmospheres containing gasoline, hexane, naptha, benzine, butane, alcohol, acetone, benzol, lacquer solvent vapors, or natural gas.

 

Locations which are hazardous due to the presence of combustible dust in the air.

• Division I - Locations in which hazardous concentrations in the air exist continuously, intermittently, or periodically under normal operating conditions.
• Division II - Locations in which hazardous concentrations are handled, processed, or used but are normally within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown.

• Group E - Atmospheres containing metal dust, including aluminum, magnesium and their commercial alloys and other metals of similarly hazardous characteristics.
• Group F - Atmospheres containing carbon black, coal or coke dust.
• Group G - Atmospheres containing flour, starch, or grain dust.