15-112 Light and Air Provisions
(a) Spaces other than rooms:
(1) Mezzanines shall be lit and ventilated in accordance with the provisions of Section 27-732 (Natural light requirements) and Article 6 (Standard of Natural Ventilation) of the New York City Building Code.
(2) Cellar space is not permitted in dwelling units with three and one-half rooms or fewer, unless such dwelling units contain at least 1,200 square feet of interior floor area.
(3) Spaces, other than "living rooms," kitchens, bathrooms or mezzanines, with a minimum width of five feet in the narrowest dimension measured perpendicular to a wall enclosing such space, are not permitted in dwelling units with two rooms or fewer, unless such dwelling units contain at least 1,200 square feet of interior floor area.
(b) Every dwelling unit shall meet the light and air requirements of Section 277 of the Multiple Dwelling Law.
(c) Width to depth ratio
Where there is more than one dwelling unit per story, the average width of each dwelling unit shall be at least one fourth of the depth. Depth is the farthest point within the dwelling unit from the exterior building wall containing windows used to meet the requirements of paragraph (b) of this Section, measured perpendicular to such building wall. Width is the distance between exterior dwelling unit walls measured perpendicular to the depth.