§ 254. Egress from dwellings. 1. Nursing and convalescent homes, homes for the aged and boarding and nursery schools, two stories in height erected after July first, nineteen hundred fifty-seven, child caring institutions, two stories in height, erected after July first, nineteen hundred sixty-two and all dwellings three or more stories in height shall have at least two means of egress and, except as otherwise provided in the case of a pitched or sloped roof, shall extend to the roof from an entrance story, street, court or yard. The entrances to such means of egress at every story shall be at least fifteen feet distant from each other unless they are on opposite sides of a public hall. One means of egress shall be a stair constructed as provided in section two hundred fifty-seven. The other means of egress shall be either another such stair or a fire-stair or a fire-escape constructed as provided in section one hundred thirty-three.

2. If the number of living rooms on any story, or in any section of any story, above the entrance story exceeds twenty, there shall be an additional stair or a fire-stair extending from the entrance story to the roof for each twenty rooms or fraction thereof on such story or section thereof in excess of twenty, except that no additional stair shall be required for such excess on any story or section thereof if the number of living rooms thereon does not exceed thirty and if in addition one stair serving such story or section and every entrance hall or other public hall connected therewith is everywhere four feet six inches or more in clear width.

3. There shall be accessible from every apartment two means of egress from the dwelling, one of which shall be an enclosed stair complying with the provisions of section two hundred fifty-seven within fifty feet from a means of egress from such apartment.

4. Nursing and convalescent homes, homes for the aged, and boarding and nursery schools, one story in height, erected after July first, nineteen hundred fifty-seven, and child caring institutions, one story in height, erected after July first, nineteen hundred sixty-two, shall have at least two means of egress from the dwelling accessible to every apartment providing free and unobstructed egress by a door opening to the outer air.