Types and Definition of Hazardous Locations:
Class I, Division I
Locations in which hazardous concentrations of flammable gases or vapors exist continuously, intermittently, or periodically under normal operating conditions.
Class I, Division II
Locations in which volatile flammable gases are hazardous liquids, vapors or gases will normally be confined within closed containers or closed systems from which they can escape only in case of accidental rupture or breakdown of such systems or containers, or in case of abnormal operation of equipment.
Class...
