Illumination is not required in Group U occupancies.
The means of egress illumination level shall not be less than one foot-candle (11 lux) at the floor level.
In assembly occupancies, the illumination of the floors of exit access shall be at least 0.2 foot-candle (2.2 lux) during periods of performances or projections involving directed light.
The power supply for means of egress illumination shall normally be provided by the premises' electrical supply. In the event of power supply failure, illumination shall be automatically provided from an emergency system for the following occupancies where such occupancies require two or more means of egress:
- Group A having 50 or more occupants. Assembly occupancies used exclusively as a place of worship and having an occupant load of less than 300 are not required to have emergency illumination.
- Group B buildings three or more stories in height, buildings with 100 or more occupants above or below the level of exit discharge, or buildings with 1,000 or more total occupants.
- Group E in interior stairs, corridors, windowless areas with student occupancy, shops, and laboratories.
- Group F having more than 100 occupants. Buildings used only during daylight hours that are provided with windows for natural light are not required to have emergency illumination.
- Group I.
- Group M buildings greater than 3,000 square feet (2879 m2) in gross sales area or exceeding one story in height.
- Group R-1. Where each guest room has direct access to the outside of the building at grade, emergency illumination is not required.
- Group R-2. Where each living unit has direct access to the outside of the building at grade, emergency illumination is not required.
- Group R-4. Where each sleeping room has direct access to the outside of the building at ground level, emergency illumination is not required.
The emergency power system shall provide power for not less than 30 minutes and consist of storage batteries, unit equipment, or an on-site generator. The installation of the emergency power system shall be in accordance with Section 604.