Category
Electrical Systems
Subcategory
Hazardous Area
Applicable standards
3
Issuing bodies
3
Description
Electrical equipment for hazardous areas — Ex d, Ex e, Ex i, Ex p, etc.
Applicable Standards (3)
IEC — 1 standard
IEC 60079 (series)
Explosive atmospheres
Equipment for use in hazardous (classified) areas — Ex d, Ex e, Ex i, Ex p. Basis for ATEX/IECEx.
Key requirements (9)
- Explosive atmosphere equipment standards (Ex). Multi-part series.
- Zone 0: explosive gas mixture continuously present (typically inside vessels).
- Zone 1: explosive mixture likely in normal operation (around vents, sample points).
- Zone 2: explosive mixture not likely / brief if it occurs (open process areas).
- Gas groups: IIA (propane), IIB (ethylene), IIC (hydrogen, acetylene). IIC most onerous.
- Temperature classes: T1 (450 °C) to T6 (85 °C) — surface temp must be < AIT of gas.
- Protection methods: Ex d (flameproof), Ex e (increased safety), Ex i (intrinsic safety ia/ib), Ex p (pressurized), Ex n (non-incendive Zone 2 only), Ex m (encapsulated).
- Equipment Protection Level (EPL): Ga/Gb/Gc for gas atmospheres.
- ATEX in EU; IECEx globally; PESO certification in India (CCOE).
NFPA — 1 standard
NFPA 70 (NEC)
National Electrical Code
US electrical installation code, including hazardous locations (Articles 500–516).
BIS — 1 standard
IS 5571 / IS-IEC 60079 series
Selection of Electrical Equipment for Hazardous Areas
Indian adoption of IEC 60079 for hazardous-area equipment selection.