N.Y.C. Admin. Code § 27-735: § 27-735 Artificial light requirements.

Adequate means for producing artificial light by electricity shall be provided in every room or floor space in every building hereafter erected and in the portions of existing buildings where alterations are performed except as follows:

(a) Artificial light need not be provided in rooms or spaces occupied exclusively during the daylight hours between one hour after sunrise and one hour before sunset, and which are provided with natural light meeting the requirements of sections 27-733 and 27-734 of article three of this subchapter.

(b) Artificial light need not be provided in rooms or spaces with less than forty square feet of floor area if they are used exclusively for storage purposes or for mechanical facilities containing no rotating or moving parts, no combustion equipment, or no other hazardous equipment.