Zone 2 — Equipment Requirements and Selection
Zone 2 is the least hazardous gas zone classification — an explosive atmosphere is unlikely to occur in normal operation, and if it does, only for short periods. Zone 2 typically applies to areas surrounding Zone 1 equipment — the volume around flanged pipe connections, the vicinity of pump seal areas, and areas adjacent to Zone 1 boundaries.
Equipment Options for Zone 2
Zone 2 allows the use of EPL Gc equipment in addition to EPL Gb and EPL Ga. The additional protection types available for Zone 2 include:
- Ex nA (non-sparking) — IEC 60079-15 — equipment that produces no arcs or sparks in normal operation
- Ex ec (energy-limited) — IEC 60079-7 — enhanced increased safety for Zone 2
- Ex nC (non-incendive) — equipment with sealed contacts
EPL Gb equipment (Zone 1 rated) is always acceptable in Zone 2, providing equivalent or higher protection.
Zone 2 equipment is generally less expensive than Zone 1 equipment because the protection requirements are less stringent. However, when in doubt about zone classification, always specify Zone 1 (EPL Gb) equipment — it provides a safety margin and avoids costly remediation if the area is later re-classified to Zone 1.
Zone 2 in Practice
Zone 2 areas are common in refineries, chemical plants, and processing facilities. Many general-purpose areas of these plants fall into Zone 2 — maintenance workshops with solvent use, areas around sealed process equipment, and zones beyond Zone 1 boundaries. Correct zone identification is essential for cost-effective and compliant installation.
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