§ 205. Separation and ventilation of stairs. 1. All stairs and
fire-stairs shall be completely separated from one another and from
every elevator or other shaft by fireproof walls. They shall be
constructed of fireproof material throughout and shall contain no wood
or other inflammable material of any kind, except that handrails of
hardwood may be provided.

2. Access to stairs and fire-stairs from any public vestibule or other
public hall shall be through fireproof doors and assemblies, with the
doors self-closing and at least three feet wide, or through pairs of
such doors at least four feet wide, containing in either case a fixed
sash glazed with wire glass at least one-quarter inch thick and at least
three hundred sixty square inches in area.

3. At the highest level of every stair and fire-stair there shall be
provided a window or a skylight. At such termination, there shall also
be an opening of at least one hundred forty-four square inches which
shall communicate directly to the outer air, which opening may be a part
of such window or skylight. Except as herein provided, such skylight
shall ccomply with the provisions of subdivision two of section one
hundred eight.