§ 143. Construction of first floor. 1. The first floor above the
lowest cellar, or, if there be no cellar, above the lowest story, shall
be fireproof or, if the dwelling be three stories or less in height,
fire-retarded. Said first floor shall be unpierced except for a stair
leading to a cellar as provided in section one hundred fifty, for lawful
pipes, conduits and ducts and for dumbwaiter and elevator shafts. Any
such dumbwaiter and elevator shafts shall be equipped at all openings
below the said first floor with fireproof doors and assemblies with the
doors self-closing.

2. Whenever the lowest cellar does not extend over more than half the
area of the dwelling, that portion of the first floor directly over such
cellar and the entire second floor above such cellar shall be
constructed as in this section prescribed for the first floor above the
lowest cellar. Whenever the lowest cellar extends over more than half,
but not all, of the area of the dwelling, only that portion of the first
floor directly over such cellar need be constructed as in this section
prescribed for the first floor above the lowest cellar.