Zone 1 / Zone 2

Zones classify hazardous gas areas by how probable an explosive atmosphere is: Zone 0 — present continuously or for long periods (inside tanks and vessels); Zone 1 — likely in normal operation (pump seals, sampling points, vent surroundings); Zone 2 — unlikely and short-lived if it occurs (the broader plant fringe). Dust equivalents are Zones 20/21/22. The classification, produced in the site’s hazardous-area study, dictates equipment: Zone 1 demands equipment protection level Gb (flameproof Ex d and Ex d e luminaires are typical), while Zone 2 accepts Gc equipment including simpler Ex e constructions — and anything certified for a stricter zone may serve a milder one, never the reverse.