Emergency lighting requirements
What US codes require for emergency lighting and exit signs in commercial buildings, in plain language, from the people who build compliance into the fixture.
The codes behind the rules
Emergency lighting rules in the US come from a few sources that overlap:
- NFPA 101, Life Safety Code: sets where emergency lighting is required, how bright, how long, and how often it must be tested.
- International Building Code and International Fire Code: adopted by most states and cities, with similar requirements for means of egress illumination and exit signs.
- OSHA 29 CFR 1910.37: workplace exit route rules, including exit sign marking and illumination.
- UL 924: the product safety standard emergency lights and exit signs are listed to.
Which edition applies depends on what your jurisdiction adopted, which is why the AHJ has the final word.
Where emergency lighting is required
In general, emergency lighting is required along the means of egress in most commercial, assembly, educational, healthcare, industrial and multifamily occupancies: exit access corridors, stairways, ramps, aisles, passageways and the exit discharge. Specific occupancy chapters add or remove requirements.
Performance requirements
Initial level: average of at least 1 foot-candle, and at least 0.1 foot-candle at any point, measured along the path of egress at floor level.
End of duration: may decline to an average of 0.6 foot-candle and a minimum of 0.06 foot-candle.
Uniformity: maximum-to-minimum ratio no greater than 40 to 1.
Transfer: emergency lighting must come on automatically when normal lighting fails.
Exit signs
Exits and the way to reach them must be marked with approved, readily visible signs, and internally illuminated signs must be listed. Letter size, illumination and placement rules are covered in exit sign requirements.
Testing requirements
Battery-powered emergency lighting must be tested for at least 30 seconds every 30 days and for at least 90 minutes every year, with written records. Self-testing, self-diagnostic units that do this automatically are allowed with visual inspections and records. Full detail in our testing guide.
Frequently asked questions
How long does emergency lighting need to last?
At least 90 minutes after normal power fails, under NFPA 101.
What is the minimum emergency lighting level?
Initially an average of 1 foot-candle along the egress path with no point below 0.1 foot-candle, declining to an average of 0.6 and a minimum of 0.06 foot-candle at the end of 90 minutes.
Is emergency lighting required in every building?
Requirements depend on occupancy type and local code. Most commercial and public buildings need it along the means of egress. Your AHJ confirms what applies.