N.Y.C. Admin. Code § 27-259: § 27-259 Classification.

Buildings, building sections and spaces shall be classified in the educational occupancy group when persons occupy them for instruction or other educational purposes except those spaces occupied as a place of assembly. These spaces shall be classified in occupancy group F-assembly, under the provisions of article eight of this subchapter. Such buildings, building sections and spaces occupied for instruction and used exclusively by adults may be classified, by the commissioner in occupancy group E-business and if so classified such buildings, building sections and spaces shall comply with the requirements for such classification.