§ 105. Separation and ventilation of stairs. 1. In a dwelling in which
one or more passenger elevators are maintained and operated opening upon
a public hall at every story, all stairs, fire-stairs and fire-towers
shall be completely separated from one another and from every elevator
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, fire-stairs and fire-tower balconies 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 three
hundred sixty square inches in area.

3. Every stair hall shall be ventilated by a window, or by movable
louvres in the skylight having an opening of at least one hundred
forty-four square inches, or by an opening of at least one hundred
forty-four square inches near the top of the stair shaft and
communicating directly with the outer air. If a window is provided which
does not open upon a street or yard, it shall be fireproof and glazed
with wire glass of good quality and have no pane more than three hundred
sixty square inches in area.