North American Hazardous Area Certification
Hazardous area certification in North America is primarily based on the Class and Division system, with increasing use of Zone-based classifications aligned with international standards.
This page explains how hazardous area certification is structured in the United States and Canada, including classification systems, listing marks, and interpretation boundaries.
Class and Division System
The traditional North American hazardous area classification system is based on Classes and Divisions defined by electrical and fire safety codes.
| Classification | Description |
|---|---|
| Class I | Flammable gases or vapors |
| Division 1 | Explosive atmosphere present during normal operation |
| Division 2 | Explosive atmosphere present only under abnormal conditions |
Use of Zones in North America
Zone-based classification systems aligned with international standards are permitted and increasingly adopted in North America.
Zone usage does not replace Class/Division by default and remains subject to applicable codes and authority approval.
Listing Marks and Certification Bodies
- UL and FM are Nationally Recognized Testing Laboratories (NRTLs)
- Listing marks indicate compliance with applicable standards and codes
- cFMus and cCSAus denote certification for both U.S. and Canadian markets
- Listing marks are not explosion protection concepts themselves
United States and Canada
While the United States and Canada share similar hazardous area concepts, regulatory frameworks and acceptance processes may differ.
Final acceptance is subject to local codes and Authorities Having Jurisdiction (AHJ).
Common Interpretation Errors
- Assuming Class/Division is automatically equivalent to Zones
- Treating listing marks as protection concepts
- Ignoring installation and configuration limitations
- Overlooking AHJ authority and local code requirements
Relationship to International Certification Schemes
North American certification systems may reference international standards but operate under distinct regulatory and code-based frameworks.
Governance & Interpretation
nterpretation of North American hazardous area certification, listing scope, and responsibility boundaries is maintained under the ExPC Technical Authority.
Reviewed and maintained by ExPC Technical Authority
Last reviewed: January 2026
