§ 258. Public halls. 1. Every public hall shall be everywhere at least three feet in clear width.

2. Except as herein provided, every public hall shall be completely enclosed with fireproof floor, ceiling and walls, and separated from every stair by fireproof partitions or walls, and all doors and their assemblies opening therefrom shall be fireproof, with the doors self-closing and without transoms. In a dwelling three stories or less in height occupied by not more than four families on each story, or in a permanently occupied dwelling or any section thereof two stories or less in height, any such hall which furnishes access to only one stair need not be separated from such stair by any partition or door and the walls of a public hall may be fire-retarded and the floors may be provided with three inches or more of incombustible materials between the beams.

3. Except in dwellings three stories or less in height and occupied by two families or less on every story, every public hall shall have at least one window opening directly upon a street or upon a lawful yard or court. There shall be such a window at the end of such hall and at right angles to its length, with an additional window in each forty feet of hall or fraction thereof beyond the first sixty feet from such end window; or the hall shall have one window opening directly upon a street, yard or court, in every forty feet of the length of such hall or fraction thereof measured from one end of the hall. Any part of a public hall that is shut off from any other part of such hall by a door or doors shall be deemed a separate hall.

4. The foregoing provisions of this section with regard to lighting and ventilation shall not apply to a vestibule or other public hall which serves as a means of access from one or more apartments opening thereon to a fire-stair meeting the requirements of section two hundred two if such vestibule or public hall is lighted and ventilated as required by sections one hundred nine and two hundred seven.