International classification system for hazardous areas under IEC/ATEX standards
Zones (Gas Atmospheres):
Zone 0: Explosive gas or vapor continuously present or present for long periods
Zone 1: Explosive gas or vapor likely to occur in normal operation
Zone 2: Explosive gas or vapor unlikely in normal operation, and if present, exists only for a short time
Zones (Dust Atmospheres):
Zone 20: Combustible dust continuously or frequently present in sufficient quantity to form explosive mixtures
Zone 21: Combustible dust likely to occur in normal operation
Zone 22: Combustible dust unlikely in normal operation, and if present, persists only for a short time
