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.
