§ 242. Cellar and basement stairs in non-fireproof tenements. 1.
Cellar stairs in non-fireproof tenements erected after April twelfth,
nineteen hundred one, which are occupied by three families or more on
any story or which are five stories or more in height, shall be governed
by the provisions of section one hundred fifty for non-fireproof
multiple dwellings erected after April eighteenth, nineteen hundred
twenty-nine. In all other non-fireproof tenements erected after April
twelfth, nineteen hundred one, any stair leading to a cellar may be
located inside the building, provided it is enclosed with fireproof
walls and is provided with fireproof doors and assemblies at both the
top and bottom, with the doors self-closing.

2. In old-law tenements exceeding a basement and three other stories
in height and provided with an inside cellar stair communicating between
the entrance story and a cellar or lower story, the opening to such
stair if located underneath the main stair leading to the upper stories
shall be enclosed from the level of the entrance story up to the
underside of the first flight of such main stairs. The soffit of such
first flight of main stairs and the partitions forming such enclosure
shall be fire-retarded or covered with twenty-six gauge metal. The
opening to such enclosure shall be provided with a fireproof door and
assembly with the door self-closing.