§ 131. Shafts, elevators and dumbwaiters. Every shaft shall be
enclosed on all sides with fireproof walls and shall have fireproof
doors and assemblies at all openings, with the doors self-closing. Not
more than three elevators or dumbwaiters shall ever be placed in the
same shaft. All dumbwaiter doors shall be fastened by an interior lock
in the shaft operated and controlled from a central point. The doors of
every elevator shaft shall be provided with an automatic device to
prevent the normal operation of the elevator unless the hoistway door at
which the car is standing is closed and locked, or unless all hoistway
doors are locked in a closed position. Such doors, except for
power-operated sliding doors, shall have a vision panel of wire glass
not exceeding one square foot in area. Every elevator shall be equipped
with a gate or door with an automatic device to prevent the normal
operation of such elevator unless such gate or door is closed.