§ 55. Egress. 1. In every transient dwelling to which this article is applicable there shall be from each story at least two independent means of egress accessible to each room, apartment or suite, except as otherwise provided in section sixty-three with respect to two story transient dwellings.

2. The first means of egress shall be an enclosed stair extending directly to a street, or to a yard, court or passageway affording continuous, safe and unobstructed access to a street, or by an enclosed stair leading to the entrance story, which story shall have direct access to a street. That area of the dwelling immediately above the street level and commonly known as the main floor, where the occupants are registered and the usual business of the dwelling is conducted, shall be considered a part of the entrance story; and a required stair terminating at such main floor or its mezzanine shall be deemed to terminate at the entrance story. An elevator or an unenclosed escalator shall not be acceptable as a required means of egress.

3. The second means of egress shall be by an additional enclosed stair, conforming to the provisions of subdivision two of this section, a fire-stair or an outside fire-escape. In a non-fireproof dwelling when it is necessary to pass through a stair enclosure which may or may not be a required means of egress to reach a required means of egress, such stair enclosure and that part of the public hall or corridor leading thereto from a room, apartment or suite, shall be fire-retarded as provided in section fifty-two or protected by a sprinkler system; in a fireproof dwelling only that part of the hall or corridor leading to such stair enclosure need be so protected.

4. Where it is impractical in such existing transient dwellings to provide a second means of egress, the department may order, in lieu of the second means of egress, additional alteration to the first means of egress and to shafts, stairs and other vertical openings as the department may deem necessary to safeguard the occupants of the dwelling, may require the public halls providing access to the first means of egress to be equipped on each story with an automatic sprinkler system, and, in non-fireproof dwellings, may also require automatic sprinkler heads in the stair which serves as the only means of egress.

5. Nothing in this section shall be deemed to require the enclosure of a stair which is ornamental provided such stair does not connect more than two stories.

6. A stair, fire-stair or fire-escape supplementary to the egress requirements of subdivisions two, three and four of this section need not lead to the entrance story or to a street, or to a yard or a court which leads to a street, provided the means of egress therefrom is approved by the department.

7. A fire-detecting system shall not be acceptable for any of the requirements of this section.

8. In lieu of enclosing stairways as required by subdivisions two and three of this section, an automatic sprinkler system may be provided on such stairs.

9. All fire-escapes erected on or after July first, nineteen hundred fifty-three, in compliance with this section, shall be arranged, constructed and maintained in accordance with the provisions of section one hundred thirty-three. Such system shall be installed, arranged and maintained in a manner satisfactory to the department and in accordance with rules adopted by the commission. It shall be unlawful to remove any fire-escape without permission from the department.