(a) Two openings for each motion picture projector shall be provided; one for the projectionist's view (observation port) shall be not larger than 200 square inches, and the other through which the picture is projected (projection port) shall be not larger than 120 square inches.
(b) Each opening shall be provided with an approved gravity shutter. Shutters shall be of not less than 10-gauge iron or its equivalent, or of ¼ inch hard asbestos board. Shutters shall be suspended, arranged and interconnected so that all shutters will close upon the operating of some suitable fusible or mechanical releasing device. Each shutter shall have a fusible link above it, and there shall also be one located over each upper projector magazine which, upon operating, will close all the shutters. There shall also be provided suitable means for manually closing all shutters simultaneously from any projector head and from a point within the projection room near each exit door. Shutters on openings not in use shall be kept closed.
(c) All shelves, furniture and fixtures within the enclosure shall be constructed of noncombustible material, except that tables may be of wood construction with no member less than 1 ½ inch in least dimension. No combustible material of any sort shall be permitted or allowed to be within such enclosure, except the films used in the operation of the projector, and film cement.
(d) Ventilation shall be provided by one or more mechanical exhaust systems which shall draw air from each arc lamp housing and from one or more points near the ceiling. Systems shall exhaust to outdoors either directly or through a noncombustible flue used for no other purpose. Exhaust capacity shall be not less than 15 nor more than 50 cubic feet per minute for each arc lamp housing plus 200 cubic feet per minute for the room itself. Systems shall be controlled from within the enclosure and have pilot lights to indicate operation. The exhaust systems serving the projection room may be extended to cover rooms associated therewith such as rewind rooms. No dampers shall be installed in such exhaust systems. Ventilation of these rooms shall not be connected in any way with ventilating or air conditioning systems serving other portions of the building.
(e) Exhaust ducts shall be of noncombustible material, and shall either be kept one inch from combustible material or covered with ½ inch of noncombustible heat insulating material.