N.Y. MRE Law § 108

§ 108. Windows and skylights for public halls and stairs. 1. Where a\nwindow or windows are required to light a public hall or part thereof,\nat least one of such windows shall be not less than two feet six inches\nwide and five feet high. Every required window in such a hall shall open\nupon a street, yard or court. On the top story of such a dwelling a\nventilating skylight of the same dimensions shall be accepted in lieu of\na window for that story.\n 2. There shall be in the roof, directly over each required stair and\nfire-stair a ventilating skylight provided with louvres or ventilators\nhaving a minimum open area of forty square inches. The roof of every\nsuch skylight shall be glazed with plain glass and equipped with\nsuitable metal screens above and below. The glazed area of every such\nskylight shall be at least twenty square feet, except that in such a\ndwelling or section thereof two stories or less in height the glazed\narea of such a skylight need be only nine square feet. In lieu of a\nskylight, a window of the same area as prescribed in subdivision one may\nbe provided. If such a window is used in lieu of a skylight, fixed\nlouvres having a minimum opening of forty square inches shall also be\ninstalled in or directly adjacent to such window.\n 3. When any stair, fire-stair or fire-tower in such a dwelling\nterminates at the level of a setback of an outer wall and such setback\nconsists of a terrace at least four feet in width, measured between the\ninside of the parapet wall and the wall of the dwelling and at least ten\nfeet in length, measured parallel to the wall of the dwelling, there may\nbe provided in lieu of such skylight a fireproof door and assembly with\nthe door self-closing giving access from such stair or fire-stair to\nsuch terrace. Such door shall have a panel at least five square feet in\narea glazed with wire glass and shall be equipped with louvres having a\nminimum open area of forty square inches.\n