N.Y.C. Admin. Code § 27-242: § 27-242 Multiple occupancy or use.

When a building or space is used for multiple purposes, involving different activities at different times, the building or space shall be given a separate occupancy group classification for each of the activities involved. The design and construction of the building or space shall be in accordance with the most restrictive provisions of this code that apply to any of the occupancy group classifications utilized. However, a minor variation of any occupancy or use of a space from technical compliance with a particular space occupancy classification shall not be prohibited if such variation is normally associated with the occupancy classification and no specific danger or hazard is created.