2006 New York Code - Windows And Skylights For Public Halls And Stairs.

 
    §  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.