Section 255. Egress from apartments

1. A dwelling three or more stories in
  height  shall  have at least two means of egress from every apartment or
  suite. Such means shall be remote from each other. Except where it opens
  into a stair as permitted in subdivision three, one means shall be to  a
  public  hall  connecting  with  an enclosed stair or fire-stair not more
  than fifty feet distant from such means. The  other  required  means  of
  egress  shall  open  either  directly  upon  a  fire-escape  or a public
  vestibule or other public hall connecting with a stair or fire-stair.
    2. Except as hereinafter provided for dwellings two stories or less in
  height, such vestibule, hall or stair shall be separated from the public
  hall or stair, on which the first means of egress opens, by a  fireproof
  wall,  unpierced  except  by a fireproof door and assembly with the door
  self-closing.  In  a  dwelling  two  stories  or  less  in  height,  the
  separating wall may be fire-retarded.
    3.  In a dwelling three stories or less in height and occupied by four
  families or less on each story, and in  any  section  of  a  permanently
  occupied dwelling which is two stories or less in height and occupied by
  four families or less on each story, a means of egress from an apartment
  may  open  directly  into  a  stair without the intervention of a public
  hall. Such means shall have a fireproof door and assembly with the  door
  self-closing and without a transom.