§ 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.