Definition of Zone 1, Zone 2 and Zone 0

Definition of Zone 1, Zone 2 and Zone 0

1. Zone 0 :A place in which an explosive gas–air mixture is present continuously, or for long periods, or frequently.

Note: Hot work is strictly prohibited. Open flames, high temperatures, and sparks are absolutely forbidden.

2. Zone 1:A place in which an explosive gas–air mixture is likely to occur in normal operation occasionally.

Note: Hot work is prohibited in principle. If work is absolutely necessary, the highest-level hot work permit must be implemented: forced ventilation, continuous gas monitoring, isolation, and supervision.

3. Zone 2:A place in which an explosive gas–air mixture is not likely to occur in normal operation,and if it does occur, it will exist only for a short time.

Note: Hot work may be carried out under a strict permit. A hot work ticket, gas detection, ventilation, and supervision are required.