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Technical summary of Class I, II and III hazardous (classified) locations

From terminology to temperature codes, and from explosion protection methods to ingress protection codes, we have assembled a comprehensive summary of technical issues pertaining to USA, Canadian, European and international IECEx hazardous locations / explosive atmospheres.

Class I (flammable gases, vapors or liquids)

• Area classification
• Gas groups
• Temperature codes
• Protection methods & standards

A closer examination of Class I, Zone requirements

• USA IEC-based Zone requirements
• USA Division-based Zone requirements

Class II (combustible dusts)

• Area classification
• Dust groups
• Temperature codes
• Protection methods & standards

Class III (ignitable fibers and flyings)

• Area classification
• Groups
• Temperature codes
• Protection methods & standards

Marking comparison for Class I, II and III equipment

• USA and Canadian Division markings
• USA and Canadian Division-based Zone markings
• USA, Canadian, European and IECEx IEC-based Zone markings

Environmental ratings for enclosures

• "NEMA" Types
• "IP" (Ingress Protection) Codes

For comments or questions on hazardous locations, please contact hazloc@ul.com.

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