2006 New York Code - Public Halls And Stairs.

 
    § 52. Public halls and stairs. The walls and ceiling of every entrance
  hall,  stair hall or other public hall, every hall or passage not within
  an apartment or suite of rooms, every dumbwaiter, elevator,  and,  every
  other  shaft,  including  stairs,  connecting  more  than two successive
  stories, shall be sealed off from every other portion  of  the  dwelling
  with fire-retarded materials, or, in lieu thereof, except in the case of
  elevator  shafts,  shall be equipped with an automatic sprinkler system.
  Except as provided in subdivision five of  section  fifty-five,  nothing
  contained in this article shall be deemed to exempt an interior required
  means  of  egress  from  the  enclosure  requirements  or  the equipment
  provided for in this section.  A  fire-detecting  system  shall  not  be
  acceptable for any of the requirements of this section.