N.Y.C. Admin. Code § 27-263: § 27-263 Classification.

Buildings and spaces shall be classified in the residential occupancy group when families or households dwell therein, or when sleeping accommodations, with or without dining facilities, are provided therein for individuals. Excluded from this group are those buildings and spaces classified under the institutional occupancy group. The residential occupancy consists of sub groups J-1, J-2, and J-3.