(A) Every common hall and stairway in residential occupancies, other than in one-and two-family dwellings, shall be lighted at all times with at least a 60 watt standard incandescent light bulb for each 200 square feet (19 m2) of floor area or equivalent illumination, provided that the spacing between lights shall not be greater than 30 feet (9,144 mm).
(B) In other than residential occupancies, means of egress, including exterior means of egress stairways shall be illuminated at all times the building space served by the means of egress is occupied with a minimum of one footcandle (11 lux) at floors, landings and treads.
(2009 Code, § 29-4-6)