N.Y.C. Admin. Code § 27-540: § 27-540 Exit lighting.

In addition to the requirements of subchapter six of this chapter, lighting shall be provided in the following areas:

(a) Safe areas. Safe areas shall be artificially lighted by electrical means at all times during occupancy of a place of assembly so as to provide illumination of at least five foot candles at the level of the floor and on the surface of all stairs, steps, ramps, and escalators within the safe area.

(b) Open exterior spaces. Yards or courts which serve as open exterior spaces shall be artificially lighted by electrical means at all times between sunset and sunrise during occupancy of a place of assembly so as to provide illumination of at least five foot candles at the level of the floor over at least the required area.