N.Y. Multiple Residence Law § 205

§ 205. Separation and ventilation of stairs. 1. All stairs and\nfire-stairs shall be completely separated from one another and from\nevery elevator or other shaft by fireproof walls. They shall be\nconstructed of fireproof material throughout and shall contain no wood\nor other inflammable material of any kind, except that handrails of\nhardwood may be provided.\n 2. Access to stairs and fire-stairs from any public vestibule or other\npublic hall shall be through fireproof doors and assemblies, with the\ndoors self-closing and at least three feet wide, or through pairs of\nsuch doors at least four feet wide, containing in either case a fixed\nsash glazed with wire glass at least one-quarter inch thick and at least\nthree hundred sixty square inches in area.\n 3. At the highest level of every stair and fire-stair there shall be\nprovided a window or a skylight. At such termination, there shall also\nbe an opening of at least one hundred forty-four square inches which\nshall communicate directly to the outer air, which opening may be a part\nof such window or skylight. Except as herein provided, such skylight\nshall ccomply with the provisions of subdivision two of section one\nhundred eight.\n