What is ATEX Zone 0 Zone 1 Zone 2 Zone 20 Zone 21 Zone 22?

A hazardous area can be defined as any location where there is risk of an explosion. But every hazardous area is different and each has specific requirements depending on the nature of the atmosphere and the elements that are present.

Zone 0
Zone 0 is an area in which an explosive atmosphere is present continuously for long periods of time or will frequently occur.

Zone 1
Zone 1 is an area in which an explosive atmosphere is likely to occur occasionally in normal operation. It may exist because of repair, maintenance operations, or leakage.

Zone 2
Zone 2 is a place in which an explosive atmosphere is not likely to occur in normal operation but, if it does occur, will persist for a short period only. These areas only become hazardous in case of an accident or some unusual operating condition.

Zone 20
Zone 20 is a place in which an explosive atmosphere, in the form of a cloud of combustible dust in air, is present continuously, or for long periods or frequently for short periods. For example, a mill or pneumatic conveying system. 

Zone 21
Zone 21 is a place in which an explosive atmosphere, in the form of a cloud of combustible dust in air, is likely to occur occasionally in normal operation. For example, bagging points and inspection ports that are frequently opened.

Zone 22
Zone 22 is a place in which an explosive atmosphere, in the form of a cloud of combustible dust in air, is not likely to occur in normal operation but, if it does occur, will persist for a short period only. For example, leaks from incorrectly fitted lids or spillages.