Glossary
What is Hazardous-area zones (Zone 0, 1, 2)?
Dividing a site by the likelihood of an explosive atmosphere: Zone 0 continuously or for long periods, Zone 1 likely in normal operation, Zone 2 rarely and briefly.
These zones are for gases and vapours; dust uses Zones 20, 21 and 22 on the same logic. Classification follows IEC 60079-10-1, based on release sources and ventilation.
Example: inside a fuel tank above the liquid is Zone 0, around the vent is Zone 1, and the wider surroundings Zone 2.
Related terms
- Equipment Protection Level (EPL)
- The equipment protection level states how safe a device is as an ignition source, and maps directly to the zones where it may be used.
- ATEX
- The European directive setting requirements for equipment used in explosive atmospheres; the name comes from the French ATmosphères EXplosibles.
- Gas groups (IIA, IIB, IIC)
- Gases classified by how easily they ignite and pass a flame: IIA least severe (propane), IIB (ethylene), IIC most severe (hydrogen, acetylene).