§ 267. Horizontal exit. 1. "Horizontal exit" means the connection by
one or more openings, protected by firedoors, through a fire wall in any
building, or through a wall or walls between two buildings, which doors
shall continuously be unlocked and the opening unobstructed whenever any
person is employed on either side of the opening.

2. Exterior balconies and bridges not less than forty-four inches in
width connecting two buildings and not having a gradient of more than
one foot fall in six, may also be counted as horizontal exits when the
doors opening out upon said balconies or bridges are fireproof doors and
are level with the floors of the building, and when all doors of both
buildings opening on such balconies or bridges are continuously kept
unlocked and unobstructed whenever any person is employed on either side
of the exit, and when such balconies or bridges are built of
incombustible material and are capable of sustaining a live load of not
less than ninety pounds per square foot with a factor of safety of four;
and when such balconies or bridges are enclosed on all sides to a height
of not less than six feet and on top and bottom by fireproof material,
unless all windows or openings within thirty feet of such balconies in
the connected buildings shall be encased in metal frames and sash and
shall have wired glass where glass is used.

3. In any case there shall be on each side of the wall or partition
containing the horizontal exit and independent of said horizontal exit,
at least one stairway conforming to the requirements for a required
exit.