Emergency Lighting & Exit Signs
NFPA 101 §7.8 – 7.10 · NFPA 111

Why emergency lighting exists

When normal power fails, occupants must still be able to see the path out. NFPA 101 §7.9 requires emergency lighting in every means of egress for buildings where a failure of illumination would leave occupants in the dark — which is essentially every assembly, business, mercantile, healthcare, educational, and industrial occupancy above a certain size NFPA 101 7.9.1. Exit signs (§7.10) mark the path; emergency lighting (§7.9) illuminates it.

Illumination requirements

• Normal power: Floors of means of egress illuminated to not less than 1 foot-candle (10 lux) measured at the floor.
• Emergency mode (initial): Not less than an average of 1 foot-candle and a minimum at any point of 0.1 foot-candle along the path of egress.
• Emergency mode (end of 90 min): Average may decline to 0.6 ft-c, minimum to 0.06 ft-c — a 3:1 max-to-min ratio along the path.
• Duration: 90 minutes on battery or generator backup NFPA 101 7.9.2.1.
• Transfer time: Illumination must be restored within 10 seconds of loss of normal power.

Exit signs (§7.10)

Every exit and exit access door must be marked by an approved sign readily visible from any direction of egress travel. Internally illuminated signs must be UL 924 listed. Letters are minimum 6 inches tall with a stroke width of at least 3/4 inch. No point in an exit access corridor may be more than the sign's rated viewing distance (typically 100 ft) from the nearest visible exit sign NFPA 101 7.10.6.

Tritium (self-luminous) and photoluminescent signs are permitted where listed, but the photoluminescent type requires a specific minimum ambient illumination on the sign face during normal operation so it remains "charged." Check the listing.

Testing — the two tests that matter

Monthly — 30-second functional test

Simulate a power failure (press the push-to-test button on battery units, or open the normal supply breaker for generator-backed systems). Verify the lights illuminate and exit signs remain lit. Duration: at least 30 seconds. Document the date and initials NFPA 101 7.9.3(1).

Annual — 1½-hour (90-minute) test

A full-duration test confirms the battery or generator actually delivers 90 minutes. Any unit that fails to maintain illumination for the full duration must be repaired or replaced. A computer-based self-testing/ self-diagnostic system that automatically performs the monthly 30-second and annual 90-minute tests and records results is permitted in lieu of manual testing NFPA 101 7.9.3(3).

Common deficiencies

• Dead batteries. Push-to-test shows green but the unit drops out after 5 minutes under actual load. Only the annual 90-minute test catches this.
• No documentation. AHJs, TJC, and CMS cite facilities that cannot produce monthly and annual test logs.
• Blocked or burned-out exit signs. Storage, decorations, or burned-out LEDs defeat the purpose.
• Exit sign behind the door swing. Must be visible from the direction of egress — a sign hidden behind a fully-open door doesn't count.
• Missing illumination at exit discharge. §7.8.1.3 requires the path outside the building (to the public way) also be illuminated.

Healthcare-specific notes

CMS and TJC expect full NFPA 101 compliance plus annotated test documentation. Many hospitals use a generator- backed emergency lighting branch rather than unit equipment; NFPA 99 and 110 govern the generator side, but the 90-minute battery-backed requirement still applies to lighting in critical branches where a transfer delay could cause harm. K-Tag 291 (Illumination of Means of Egress) is a frequent citation category when documentation is missing or tests are skipped during surveys.

References