Section 233. Bulkheads and scuttles

1. Every tenement, except as in this
  section otherwise provided, shall have in the roof a fireproof  bulkhead
  with  a  fireproof  door  and  after  January  first,  nineteen  hundred
  fifty-seven, the door shall be self-closing. Bulkheads existing on April
  eighteenth, nineteen hundred twenty-nine, shall be  lawful  and  may  be
  replaced  or  repaired with material conforming to the material of which
  such bulkhead consisted on such date.
    2. A bulkhead in the roof of an old-law tenement which is more than  a
  basement  and  four  other  stories in height or which is a basement and
  four other stories in height and occupied by three or more  families  on
  any  story,  may  be  of  wood  covered  with  metal  on the outside and
  fire-retarded on the inside. Such a bulkhead shall be  equipped  with  a
  fire-retarded door and assembly with the door self-closing.
    3.  In any old-law tenement which is four stories or less in height or
  which is a basement and four other stories in height and occupied by not
  more than two families on any  story,  no  bulkhead  shall  be  required
  provided such tenement is equipped with a scuttle located in the ceiling
  of  a  public  hall  on  the  top  story and with access thereto direct,
  uninterrupted and easily accessible to all tenants.  All  such  scuttles
  shall  be at least twenty-one inches in width and twenty-eight inches in
  length. They shall be constructed so as to be readily opened, covered on
  the outside with metal and  provided  with  stairs  or  stationary  iron
  ladders leading thereto.
    4.  Every  required  stair  in  every  tenement  erected  after  April
  eighteenth, nineteen hundred twelve, which is more than a  basement  and
  three  other stories in height shall extend to and through a bulkhead in
  the roof. Such bulkhead shall have a fireproof door  and  assembly  with
  the  door self-closing and may be constructed of wood covered with metal
  on the outside and fire-retarded on the inside.
    5. Stairs  leading  to  required  bulkheads  shall  be  fireproof  and
  constructed  as  specified  in  sections  two hundred thirty-four to two
  hundred thirty-eight inclusive, except that any such stairs existing  on
  April  eighteenth,  nineteen  hundred  twenty-nine,  shall  be permitted
  without alteration, and that any such stairs constructed after such date
  in any old-law tenement may have such width and  angle  of  ascent,  and
  risers  and  treads  of  such dimensions, as approved by the department.
  All stairs to required bulkheads shall be provided with a guide or  hand
  rail.
    6. Bulkhead doors and scuttles shall not be self-locking, and shall be
  fastened  on  the inside with movable bolts, hooks, or a lock which does
  not require a key to open it from the inside of the  dwelling.  All  key
  locks are unlawful and where existing shall be removed.