Hazardous area classification
The process of identifying and categorising areas where explosive or hazardous atmospheres may be present, to determine the type of equipment and protective measures required. Different classification systems are used in different jurisdictions.
The same term carries different legal meaning across frameworks. Read each jurisdiction entry carefully.
Also known as
By jurisdiction
UK HSE
“hazardous area classification”Exact equivalentDSEAR 2002 (regulation 7) requires employers to classify places where explosive atmospheres may occur into hazardous zones and to mark them at entry points. Zone 0 (gas, continuous presence), Zone 1 (gas, occasional), Zone 2 (gas, rare); Zone 20, 21, 22 for dusts. Equipment used in hazardous zones must be rated to the ATEX Equipment Directive categories.
Irish HSA
“hazardous area classification”Close equivalentThe Explosive Atmospheres Regulations 2003 (SI 2003/258) require area classification using the same ATEX zone system as DSEAR 2002. Zones 0, 1, 2 for gases and vapours; Zones 20, 21, 22 for dusts. Equipment categories must match the zone.
US OSHA
“classified location”Close equivalentOSHA 29 CFR 1910.307 uses the NEC (National Electrical Code) class/division/group system: Class I (flammable gases), Class II (combustible dusts), Class III (ignitable fibres); Division 1 (normal operation) or Division 2 (abnormal operation). This differs from the European ATEX zone system but serves the same purpose.
Practitioner note: ATEX zone system (GB/IE: Zones 0/1/2 for gases, Zones 20/21/22 for dusts) vs NEC class/division system (OSHA: Class I/II/III; Division 1/2). Equipment rated for one system is not automatically approved for the other without verification.