§ 107. Public halls. 1. Every public vestibule or other public hall shall comply either with the provisions of section one hundred forty-nine for non-fireproof multiple dwellings, so far as applicable, or with the provisions of subdivision two of this section, except that the provisions as to ventilation shall not apply to any part of an entrance hall within sixty feet in a straight line from an entrance door.

2. If such a dwelling does not comply with the applicable provisions of section one hundred forty-nine, it shall comply with all of the following:

a. Every public vestibule or hall shall be everywhere at least three feet eight inches in clear width.

b. Every such public vestibule or hall shall be separated from all other parts of the dwelling by fireproof walls.

c. All openings from such a public vestibule or hall to stairs, fire-stairs, fire-tower balconies, shafts, apartments or suites of rooms shall be protected by fireproof doors and assemblies, with the doors self-closing, except that such doors and assemblies shall not be required in any fireproof class B multiple dwelling for any apartment consisting of one room opening directly upon a public hall or for any apartment of three rooms or less in a college or school dormitory.

d. Such a public vestibule or hall shall not be required to have a window, but if it does not have a window opening to the outer air it shall be equipped for artificial lighting and be properly lighted at all times.

e. Except for that part of an entrance hall within sixty feet in a straight line from an entrance door such a public vestibule or hall without a window to the outer air shall be ventilated to the outer air by means of gravity vent flues at least twelve inches in each dimension or by mechanical means approved by the department. There shall be at least one vent flue opening of at least twelve inches in each dimension for each one thousand cubic feet of air content of such public vestibule or hall. Such vent flues shall be continuous for the height of the dwelling and the openings at each story shall be equipped with fire dampers held open by a fusible link at each opening and properly hooded or provided with louvres at the top above the roof.

f. If a window to the outer air is provided in any such public vestibule or hall, such vestibule or hall shall nevertheless be ventilated as provided in paragraph e, except that if such a window has a glazed area of at least twelve square feet and at least one tenth of the superficial floor area of the vestibule or hall, readily accessible to the outer air to the extent of at least five and one-half square feet of its area, no vent flues need be provided within a distance of forty feet from each side of such window.

3. The requirements of this section as to ventilation shall apply to all parts of an entrance hall more than sixty feet distant in a straight line from an entrance door, to all returns or recesses that lead to elevators and extend farther from the hall which they adjoin than four times their width, and to all other returns or recesses from entrance halls that extend farther than their width.

4. 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.