§ 36. Windows and skylights for public halls and stairs. 1. In every
multiple dwelling erected after April eighteenth, nineteen hundred
twenty-nine, one at least of the required windows provided to light each
public hall or part thereof shall be at least two feet six inches wide
and five feet high. Every required window in such a hall shall open upon
a street, court, yard or space above a setback. On the top story of such
a dwelling a ventilating skylight of the same dimensions shall be
accepted in lieu of a window for that story.

2. In every multiple dwelling erected after April eighteenth, nineteen
hundred twenty-nine, there shall be in the roof, directly over each
required stair, fire-stair and fire-tower, a ventilating skylight
provided with ventilators having a minimum opening of forty square
inches or with fixed or movable louvres. The roof of every such skylight
shall be glazed with plain glass and equipped with suitable wire screens
above and below. The glazed area of every such skylight shall be at
least twenty square feet, except that in a class A dwelling or section
thereof two stories or less in height and occupied by not more than two
families on each story and in dwellings three stories in height erected
pursuant to plans filed with the department on or after May first,
nineteen hundred fifty-nine and occupied by not more than one family on
each story, the glazed area of such a skylight need be only nine square
feet. In lieu of a skylight a window of the same area as prescribed in
subdivision one may be provided. If such a window is used in lieu of a
skylight, fixed louvres having a minimum opening of forty square inches
shall also be installed in or directly adjacent to such window.

3. When any stair, fire-stair or fire-tower in such a dwelling
terminates at the level of a setback of an outer wall and such setback
consists of a terrace at least four feet in width, measured between the
inside of the parapet wall and the wall of the building, and at least
ten feet in length, measured parallel to the wall of the building, there
may be provided in lieu of such a skylight a fireproof door and assembly
with the door self-closing giving access from such stair, fire-stair or
fire-tower to such terrace. Such door shall have a panel at least five
square feet in area glazed with wire glass and shall be equipped with
fixed or movable louvres with an opening of at least forty square
inches.