Egress Lighting Illuminance Compliance Check (NFPA 101 / IBC)
Egress illuminance against NFPA 101 / IBC: normal at least 1 fc at every point.
Example
You enter
- Average illuminance (fc) 1.2
- Minimum illuminance (fc) 0.15
- Maximum illuminance (fc) 3
- Mode emergency-initial
You get
- Max min 20
Checked against published worked examples from: Consulting-Specifying Engineer (Scott Gibbs, PE); International Code Council.
Details, formula, and sources
ScopeEmergency initial 1.0 fc avg / 0.1 fc min, 90-min end 0.6 / 0.06, max/min <= 40:1. A 1.2/0.15/3.0 fc corridor passes the emergency-initial test but fails normal lighting (0.15 fc < 1 fc); a 0.05 fc dark spot fails the emergency minimum even at a good average. The adopted code and AHJ govern.
Formula or tablenormal: min >= 1.0 fc at every point; stairway: also avg >= 10 fc; emergency initial: avg >= 1.0 fc, min >= 0.1 fc; emergency 90-min end: avg >= 0.6 fc, min >= 0.06 fc; emergency max/min <= 40:1; pass = all.
Source and editionThe NFPA 101 Life Safety Code / IBC means-of-egress illumination requirements, by name.
Free accessThe egress illumination minimums are in NFPA 101 and the IBC (NFPA publishes free-to-read access; many jurisdictions post the adopted IBC). The adopted edition and the AHJ govern.
What governsEstimate. AHJ and licensed professional govern.
API field namesavg_fc, min_fc, max_fc, mode, max_min
- Normal minimum at least 1 fc at every point of the walking surfaceIBC 2027 1008.2.1 / NFPA 101 7.8.1.3
- Stairway at least 10 fc average along an interior exit stairway and its landings in useIBC 2027 1008.2.1 (2021: exit access and exit stairways)
- Emergency initial 1.0 fc average, 0.1 fc minimumNFPA 101 7.9.2.1 / IBC 2027 1008.3.2 [1008.3.5 in IBC 2021]
- Emergency 90-min 0.6 fc average, 0.06 fc minimum at the end of the 90-minute periodNFPA 101 / IBC
- 40:1 ratio maximum-to-minimum must not exceed 40:1; verify the adopted editionscope of this tile