§ 57. Vertical and horizontal openings. In order to prevent the vertical and horizontal spread of fire, smoke and gases, it shall, in addition to other applicable provisions of this article, be necessary to comply with the requirements of this section.

1. All doors opening from shafts, stair halls or stairs and the door assemblies shall be fire-retarded with the doors self-closing and without transoms or any other opening. Except in the case of elevator shafts, such shafts, stair halls or stairs may be protected by an automatic sprinkler system in lieu of fire retarding.

2. All other doors opening upon entrance halls or other public halls or corridors in every part of the dwelling shall be self-closing, except where such dwelling is equipped throughout with an approved type automatic sprinkler or fire-detecting system. It shall be unlawful to attach to or maintain on or about any door required to be self-closing any device which prevents the self-closing of such door.

3. Every existing interior glazed sash, window or opening, other than a door, or a fireproof sash, window or opening glazed with wire glass, in any partition forming required enclosures around stairs or shafts shall be removed and the openings closed up and fire-retarded.