International Classifications

Developed by the International Electrotechnical Commission

GASES & VAPOURS

Zone 0: an area in which an explosive gas-air mixture is continuously present or present for long periods of time.

Zone 1: an area in which an explosive gas-air mixture is likely to occur in normal operation.

Zone 2: an area in whcih an explosive gas-air mixture is not likely to occur and, if it occurs, will exist only for a short time.

DUSTS

Zone 20: an area in which an explosive dust-air mixture is continuously present or present for long periods of time.

Zone 21: an area in which an explosive dust-air mixture is likely to occur in normal operation.

Zone 22: an area in whcih an explosive dust-air mixture is not likely to occur and, if it occurs, will exist only for a short time.