2006 New York Code - Bulkheads And Scuttles.

 
    §  60.  Bulkheads  and  scuttles.  1.  There shall be a fire-resistive
  bulkhead in the roof over, or connecting directly by means of  a  public
  hall  with  the  highest portion of every stair extending to the highest
  story below the main roof.  Stairs leading to such  bulkheads  shall  be
  fire-retarded  as required for other public stairs and shall have at the
  top fireproof doors and assemblies  with  the  doors  self-closing.  All
  stairs to required bulkheads shall be provided with a guide or handrail.
  A  scuttle so constructed as to be readily opened may be substituted for
  a bulkhead in dwellings not exceeding three stories and  a  basement  in
  height.  Such  scuttle  shall be at least twenty-one inches in width and
  twenty-eight inches in length, covered on the  outside  with  metal  and
  provided with a stationary iron or steel ladder leading thereto.
    2. When a dwelling has a pitched or sloping roof with a pitch or slope
  of more than fifteen degrees, no bulkhead or scuttle, or stair or ladder
  leading thereto shall be required.
    3.  A  bulkhead  door or scuttle shall never be locked with a key, but
  may be fastened on the inside with movable  rustproof  bolts  or  hooks.
  All key locks shall be removed.
    4.  Bulkheads  and  stairs  leading  thereto  existing  on July first,
  nineteen hundred fifty-two, shall be permitted provided the stairs  have
  such angle of ascent and treads of such dimensions as may be approved by
  the department.