§ 144. Egress from dwellings. 1. A dwelling three or more stories in height shall have at least two means of egress extending 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 one hundred forty-eight. The other means of egress shall be either another such stair or a fire-escape constructed as provided in section fifty-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 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, or fire-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 are everywhere four feet six inchs 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 a stair within fifty feet from a means of egress from such apartment. For such dwellings erected under plans filed in the department after September first, nineteen hundred fifty-one, such stair shall also be enclosed and comply with the provisions of section one hundred forty-eight.

4. Whenever more than two stairs are required, one or more of such stairs may be fire-stairs or fire-towers, provided that there shall never be more than one such fire-stair or fire-tower for each two other required stairs.