2006 New York Code - Parapets On Exterior Walls.

 
    § 27-333 Parapets on exterior walls. Parapets shall be provided on all
  exterior  walls  of  buildings of construction class II-A, II-B, or II-C
  that have roof construction of combustible materials.
    (a) Exceptions. A parapet need not be provided on the exterior wall of
  any building:
    (1) That is less than twenty-two feet high; or
    (2) Whose roof has  a  pitch  of  more  than  twenty  degrees  to  the
  horizontal   and  whose  overhang,  fascia,  cornice  or  gutter  is  of
  noncombustible  construction,  or  if  of  combustible  construction  is
  separated  from the roof and ceiling construction by construction having
  the fire-resistance  rating  required  for  the  exterior  wall  of  the
  building.   Combustible   members,  excluding  roof  sheathing  and  its
  supporting members, if covered by a class A roof covering and  complying
  with  the  restrictions  as  required by section 27-335 of this article,
  shall not extend through this construction, but shall have at least four
  inches of solid noncombustible material below, at the sides, and at  the
  ends of such members; or
    (3)  That is provided with a fire canopy at, or not more than two feet
  below the roof level, continuous around that portion of the wall that is
  without a parapet, constructed as required by subdivision (f) of section
  27-331 of this article.
    (b) Construction. Parapets required under this  section  shall  be  of
  materials and assembly having at least the fire-resistance rating of the
  wall below, and shall be at least two feet high.