Installing exit signs in hazardous environments requires more than standard fixtures. In areas where flammable gases, vapors, dusts, or fibers are present, using standard electrical equipment can increase the risk of fire or explosion. That’s why hazardous location exit signs are built with specialized sealed housings to prevent sparks from igniting dangerous atmospheres. For compliant options, explore our hazardous location exit signs.
Last updated: August 2025
Quick Picks
Pick Class & Division
- Class I: Gas/Vapor (e.g., hydrogen, propane).
- Div 1: Hazard present in normal operation.
- Div 2: Hazard present abnormally (leaks/maintenance).
Verify Listings
- UL 924 egress listing.
- NEC Class/Division/Group on nameplate.
- Temperature code (T-code) matches environment.
Install Right
- Use proper seals/conduits & fittings.
- Maintain gasket integrity.
- Document tests for AHJ inspections.
What Are Hazardous Location Exit Signs?
These products are often called explosion proof exit signs. They use sealed, heavy-duty housings and spark-arresting designs to prevent ignition of the surrounding atmosphere. Selection starts with the site’s classification: Class (hazard type), Division (likelihood of presence), and Group (specific gas/dust). The right rating keeps your facility code-compliant and workers safe.
Understanding the difference between Class 1 Division 1 and Class 1 Division 2 helps avoid over- or under-specifying equipment. Div 1 covers areas where explosive gas/vapor is routinely present during normal operation. Div 2 covers adjacent or abnormal-occurrence areas where the hazard appears only if something goes wrong (leaks, maintenance, handling).
Hazardous Classification System (NEC)
| Class | Groups (Examples) |
|---|---|
| Class I (Gases & Vapors) | Group A – Acetylene; Group B – Hydrogen; Group C – Ethylene; Group D – Propane |
| Class II (Dusts) | Group E – Metal Dust; Group F – Coal Dust; Group G – Grain Dust |
| Class III (Fibers) | No sub-groups (easily ignitable fibers/flyings) |
Always confirm Division (1 or 2) and the temperature code (e.g., T4, T5) required by your AHJ and process conditions.
Where Class 1 Division 1 Exit Signs Are Required
Class 1 Division 1 exit signs are used where flammable gases or vapors are present under normal operating conditions. These signs are fully sealed to prevent ignition of gases that could enter the fixture.
Examples of Div 1 Environments:
- Paint spray booths
- Dry-cleaning facilities
- Fueling stations and vehicle maintenance bays
- Petrochemical processing plants
- Gas utilities and natural gas plants
Class 1 Division 2 – Adjacent or Low-Risk Areas
Division 2 zones are adjacent to Division 1 areas. These locations have flammable materials present only occasionally—for example during leaks, maintenance, or material transfer. Fixtures here don’t require the same level of sealing as Div 1 equipment, but must still be rated to prevent ignition during an abnormal event.
Making It Simple: Div 1 vs Div 2
Analogy:
- Division 1: The device must operate safely even if continuously surrounded by gasoline vapors.
- Division 2: The device must remain safe if a sudden gasoline vapor leak occurs long enough to shut the system down.
Div 1 exit signs are airtight and spark-proof; Div 2 signs prioritize intrusion protection for intermittent exposure.
Specifying Enclosures, IP/NEMA & T-Codes
Beyond matching Class/Division/Group, specifiers should verify enclosure and thermal ratings that determine real-world survivability. For washdown or outdoor exposure, look for NEMA 4/4X or equivalent IP66/IP67 ingress protection to guard against water, dust, and corrosive atmospheres; stainless or powder-coated housings help in marine or chemical settings. The T-code (e.g., T4, T5) defines the fixture’s maximum surface temperature—critical when vapors have low ignition points. In hot process areas, confirm the fixture’s ambient rating (often up to 40–55 °C) and consider breather/drain fittings where permitted to reduce condensation. Battery and electronics service should not compromise the seal—follow OEM torque specs on covers and replace gaskets if damaged. Finally, coordinate with the AHJ: submit cut sheets that show UL 924 egress listing, the precise hazardous-location markings, and temperature code so approvals move quickly. For outdoor, wet-prone egress paths, pair your spec with best practices from our Wet Location Emergency Lights – Complete Buyer’s Guide.
Hazardous Location Exit Sign Applications
Selecting the correct rating ensures compliance with OSHA, NFPA, and NEC—while protecting people and property. Whether you’re outfitting a manufacturing plant, fuel depot, or chemical storage site, choose fixtures with the exact Class/Division/Group and T-code required by your process and ambient conditions. Proper installation—sealed conduits, correct fittings, intact gaskets—matters as much as the nameplate.