N.Y.C. Admin. Code § FC 704: Section FC 704: Floor Openings and Shafts

704.1 Enclosures.

Interior vertical shafts, including stairways, elevator hoistways, service and utility shafts, that connect two or more stories of a building shall be enclosed or protected as specified in the construction codes, including the Building Code. When openings are required to be protected by the construction codes, including the Building Code, openings into such shafts shall be maintained self-closing or automatic-closing by smoke detection. Existing fusible-link-type automatic door-closing devices are allowed if the fusible link rating does not exceed 135°F (57°C).