§ 56. Exit and directional signs. Every means of egress shall be
indicated by a sign reading "EXIT" in red letters at least eight inches
high on a white background, or vice versa, illuminated at all times
during the day and night by a red light of at least twenty-five watts or
equivalent illumination. Such light shall be maintained in a keyless
socket. On all stories where doors, openings or passageways giving
access to any means of egress are not visible from all portions of such
stories, directional signs shall be maintained in conspicuous locations,
indicating in red on a white background, or vice versa, the direction of
travel to the nearest means of egress. At least one sign shall be
visible from the doorway of each room or suite of rooms. Existing signs
and illumination may be accepted if, in the opinion of the department,
such existing signs and illumination serve the intent and purpose of
this section. Supplementary stairs, fire-stairs or fire-escapes which
do not lead to the entrance story or to a street or to a yard or court,
leading to a street, shall be clearly marked "NOT AN EXIT" in black
letters at least four inches high on a yellow background, and at the
termination of each such stair, fire-stair or fire-escape, there shall
be a directional sign indicating the nearest means of egress leading to
a street. All signs shall be constructed, located and illuminated in a
manner satisfactory to the department.