Last updated: October 2025
UL 924 made simple—where emergency lights are required, how to test them, and how to choose the right unit for your space.
UL 924 Quick Reference
- 90-minute performance: fixtures must provide egress illumination for at least 90 minutes during power loss.
- Illuminance: typical design targets ~1 fc average, no point below 0.1 fc along the path of egress.
- Transfer time: emergency mode within 10 seconds of power failure.
- Listing: use UL 924-listed equipment; follow the installation instructions for compliance.
- Testing: monthly 30-second and annual 90-minute tests (self-testing units automate this).
Where Is Emergency Lighting Needed?
Provide code-required illumination along the means of egress—corridors, stairwells, ramps, aisles, discharge doors—and in life-safety rooms (e.g., fire pump, generator).
Types & Form Factors
- Thermoplastic — value choice for most interiors.
- Steel — high-abuse/industrial; pair with guards.
- Architectural / Die-cast Aluminum — design-forward, durable.
- Recessed & low-profile — clean ceilings/walls.
- Wet-location — outdoor, washdown, cold (use heaters as needed).
- High-lumen — tall bays, large open areas.
- Remote-capable bases & remote heads — extend coverage from one battery unit.
- Also consider combo exit sign + emergency light units where signage and lighting combine.
Wiring & Installation
- Hardwired: permanently connected to building power with charger and battery for emergency mode.
- Mounting: wall/ceiling back-box, pendant, or recessed (plan plenum/clearances).
- Outdoors: choose wet-location listings and corrosion-resistant hardware.
Inspection & Maintenance
- Monthly: 30-second functional test; verify indicators.
- Annual: 90-minute discharge test; document pass/fail.
- Logs: keep test records and corrective actions for inspections.
Reduce manual labor with self-testing emergency lights that automate monthly/annual checks and log status codes.
Selection & Sizing
- Environment: indoor vs. wet-location; temperature (heaters for cold).
- Coverage: beam spread and aiming; step up to high-lumen for tall ceilings.
- Remote heads: use a remote-capable base to power remote heads; match voltage (6V/12V), size load for 90 min, account for voltage drop.
- Finish/material: architectural/die-cast for design, steel for abuse, thermoplastic for standard interiors.
Energy & Adaptive Features
LED emergency lights minimize energy. Options like photocells, occupancy sensors, and self-testing reduce costs and help you stay inspection-ready.
Local Code Notes
NYC and Chicago have unique signage/visibility preferences and, in some cases, metal-housing requirements. Always confirm with your AHJ.
Common Mistakes to Avoid
- Using damp units in true outdoor/washdown areas—choose wet-location listings.
- Under-sizing runtime when adding remote heads to a base unit.
- Skipping the annual 90-minute test or failing to keep logs.
- Ignoring temperature ratings—add heaters for freezers/cold climates.
AHJ Inspection Packet Checklist
- One-line diagram / locations & mounting heights
- UL 924 spec sheets and install instructions for each model
- Monthly/annual test logs and any corrective actions
- If using remote heads: voltage, wire runs, load calc for 90 minutes
Summary: Compliance in 5 Steps
- Identify required areas
- Choose UL 924-listed fixtures
- Install correctly for the environment
- Test and document
- Verify local amendments with your AHJ
Download Essential Emergency Lighting Guidelines for Safety and Compliance (PDF)