(1) The projection of nitrocellulose film shall be only from within a booth which meets the requirements of this section as to construction, equipment and accessory rooms.

(2) Where cellulose acetate or safety film is used exclusively no projection booth is required but if such a booth is used only the following subdivisions of this section shall apply: paragraph (1) of subdivision (b); subdivision (c); paragraph (2) and (3) of subdivision (e); subdivisions (g), (h) and (i).

(3) Any booth wherein only cellulose acetate or safety film may be used in accordance with this Part, shall have posted or painted upon its exterior in letters at least two inches high, the following notice:

(1) Motion picture projection booths shall be at least 10 feet from front to rear and eight feet in width and height. The area shall be such as to provide not less than 30 inches clearance at the sides and rear of each projection machine between lamp housings and 30 inches at the rear of each spot or effect machine.

(2) The walls, ceilings, and floors of such booths shall have a fire-resistance rating of at least one hour. Only incombustible material shall be used in the booth construction and all joints therein shall be tight enough to prevent the discharge of smoke. Floor surfacing materials shall be cemented to the floor. Generator, film storage and rewinding rooms adjoining projection booths shall be subject to the same construction requirements as the booths.

(1) Motion picture projection booths shall have at least two exit doorways, located remote from each other, each at least 24 inches wide and 68 inches high and provided with self-closing fire doors opening out which have a fire-resistance rating of at least three quarters of an hour. Any locks on such doors shall be openable without a key from the inside. In no case shall any such doors be kept open during any exhibition. Both exit doors shall provide access to an open area or passage not more than eight inches below the door sill, or, where located at a higher level, to a platform providing access to stairways at least 30 inches wide which may be unenclosed, or to one such stairway and a ladder.

(2) Such platforms shall be at least two feet deep and extend from the hinge jamb of the door to at least two feet beyond the lock jamb of the door. Guard rails shall be provided at the edge of such platforms except where the stairway or ladder joins it.

(3) Such stairways shall be of incombustible material with risers not exceeding and treads not less than nine inches. Such ladders shall be of incombustible material with steps not less than 18 inches wide and shall be provided with handrails. The pitch of such ladders shall not exceed 60 degrees from the horizontal.

(4) Such open areas, passages, stairways, or stairway and ladder, shall either directly or through some exitway, provide access to a street.

(5) The required exits from the projection booth may be through the rewinding and generator rooms, respectively, provided that the exits from such rooms are fire doors as required above opening in the direction of exit travel.

(1) One opening not exceeding 144 square inches shall be provided for each motion picture machine and one opening for observation, not exceeding 200 square inches, for each machine. Each opening shall be provided with a gravity shutter of not less than one-eighth inch sheet metal or three-eighths inch hard asbestos board with a lap of at least one inch all around and set in substantial metal guides. Each shutter shall be controlled by an approved heat-actuated device near the ceiling and there shall also be an approved heat-actuated device located over each upper projector magazine which will close all shutters. Means shall also be provided for the manual closing of all shutters from a point near each exit door.

(2) There may be not more than two additional openings neither of which shall exceed seven and one-half square feet in area, for stereopticon or spotlight machines. An additional opening for observation, not exceeding 200 square inches in area, may be provided for the dimmer bank, for the rewinding room and for the toilet room. All such openings shall be similarly protected by gravity shutters.

(1) Nitrocellulose film shall be kept and handled only in projection booths, rewinding rooms or in special storage rooms provided for such purposes. The total quantity so kept or handled shall not exceed 50,000 feet at any one time. The quantities of film kept or handled in the respective rooms shall not exceed the following:

(2) No flammable liquid or cement exceeding one pint in amount shall be kept in a projection booth, rewinding or other accessory adjoining room.

(3) Smoking is prohibited and a “NO SMOKING” sign shall be posted in a conspicuous place in each such room.

(1) Cabinets for the storage of nitrocellulose film shall be approved and have a capacity not in excess of 25,000 feet and shall be either of the sectional or vented type.

(2) The sectional type shall be so designed that each reel is stored in an individual compartment and can burn out without communicating fire to film in an adjoining compartment. The racks or drawers shall be so arranged that the material immediately adjacent to the partitions is kept at least one-half inch away from the partition on either side by spacers. Separating partitions, bottom, top, doors and sides shall be at least one and one half inches of asbestos board, enclosed between steel or iron sheets of not less than No. 22 U. S. gauge. All joints shall be welded. Compartment doors shall be so arranged as to close automatically when released and remain closed.

(3) The vented type shall be constructed of at least No. 18 U. S. gauge steel or iron sheets with double walls, bottom, top and doors having at least one and one-half inch space between walls. All joints shall be welded. Doors, when released, shall close and latch automatically at top, bottom and side. An automatic sprinkler head, protected by a wire mesh enclosure shall be provided and may be connected to the house supply by not less than one inch pipe, provided that the water pressure at that level be not less than 15 pounds per square inch. A vent flue to outer air having a minimum effective cross-sectional area of 18 square inches shall be provided.

(4) Vent flues shall be of construction equivalent to No. 18 U. S. gauge riveted metal and where installed inside the building shall be covered with one inch of incombustible heat insulating material and be no nearer than nine inches to any combustible material. Each vent which opens directly through an exterior wall shall be protected against the weather by a single thickness of glass one-sixteenth inch thick, painted a dark color, mounted in a sash arranged to open automatically in case of fire by the use of an approved heat-actuated device placed inside the cabinet or inside the vent immediately adjacent thereto. The total area of the glass shall be taken as the effective sectional area of the vent opening. A light wire screen not more than one-eighth inch mesh shall also be placed over each vent, so arranged as not to interfere with the automatic operation of the sash.

(5) The outlets of such vent flues shall be above the roof of the building or be made to face on a clear exterior space of at least 25 feet. Where facing on a street or court the outlet shall be located at least eight feet above the grade and be provided with a metal deflector so that gas and flame will be deflected upward.

(1) Ventilation shall be provided to exhaust not less than 15 cubic feet per minute for each arc lamp housing. In addition, at least eight air changes per hour shall be supplied in the projection room by a separate duct, located in the lower portion of a side wall. Every supply duct shall be provided with a gravity shutter, of not less than one-eighth inch sheet metal or three-eighths inch hard asbestos board, controlled by an approved heat-actuated device and also manually as required by subdivision (d) of this section for shutters of operating openings. If dampers are provided in exhaust ducts they shall be arranged to open completely and automatically in case of fire, except dampers on the lamps which may be manually operated. Exhaust ducts shall be of incombustible materials and so insulated that their temperature shall not exceed 160 degrees Fahrenheit when there is any likelihood that they may come into contact with persons or combustible materials. They shall discharge directly to the outer air or through an enclosure used for no other purposes and constructed of incombustible materials having a fire-resistance rating of at least one hour.

(2) The exhaust systems shall be controlled from the motion picture booth and have pilot lights to indicate their operation. The system serving the booth may be extended to include the rewinding and other adjoining accessory rooms, for which at least eight air changes per hour shall be provided, but shall not be connected in any way with systems serving other portions of the building.

(3) The projection room, rewinding and other accessory rooms shall be provided with separate air intakes of incombustible material having a cross-sectional area of at least one square inch for each c.f.m. to be exhausted. Fresh air intakes other than those direct to outer air shall be provided with fire shutters arranged to operate automatically as required by subdivision (d) of this section. If any window is provided in the booth, it shall be a fire window opening directly to the outside of the building, but no window may be considered as part of the mechanical ventilating system required herein.

(1) All shelves, furniture and fixtures within any motion picture projection booth shall be entirely constructed of incombustible materials. Metal cans with self-closing covers shall be provided for holding waste materials and film clippings. Hot carbons shall be placed in an insulated metal container or a pail of sand. No combustible materials not essential to normal use of the booth shall be stored therein.

(2) All electrical equipment used in the booth shall be properly grounded.