N.Y. Multiple Residence Law § 259

§ 259. Cellar and basement stairs. A cellar or basement stair located\ninside the dwelling shall be entirely enclosed with fireproof walls and\nbe provided, at all openings, with fireproof doors and assemblies, with\nthe doors self-closing, except that in any dwelling three stories or\nless in height, such stair may be enclosed with walls or partitions\nconstructed of fire-resistive materials.\n