Journal of the Society of Motion Picture Engineers (1930-1949)

stantial enclosure is certainly needed. The physical strength alone required to safely support the weight of the necessary equipment, and to allow for the additional weight of four or more persons who may be in the room at one time, calls for the specification of a heavy reinforced concrete floor constructed according to the recommendations of a qualified structural engineer. Also, and for similar reasons, the four walls of the room should be designed to assure structural security and adequate fire protection as well as the necessary physical strength required to support electrical raceways and heavy equipment items which may be mounted on these walls. From long experience in projection-room design, it seems advisable to call for ceilings not less than 9 ft above the projection-room floor level, and of structurally strong and fireproof construction. Costly films, sound and projection systems need protection from theft and from fire hazards elsewhere in the theater as well as vice versa. Solid, fireproof enclosures, with approved fireproof doors equipped with trustworthy locks, are thus well justified whether or not the films used introduce any special fire hazards. In the event a fire does occur in the projection room, it is instantly and imperatively necessary to completely isolate the room from the auditorium in order to prevent possible audience panic. Panics kill far more people than actual fires do. Projection and observation port openings must be equipped with gravity-operated, automatically controlled, approved steel fire shutters actuated by a master control cord and by 160° fusible links, located immediately above and within 6 in. of the upper magazine of each projection machine. In the event of a projectionroom fire, it is necessary to exhaust promptly all smoke and odors to the outside air. This may be accomplished by means of an adequate, forced-draft ventilating system; this system may also serve to exhaust normally the gases and carbon ash from carbon-arc lamp enclosures. A natural gravity vent, with adequate cross-sectional area extending through the projection room ceiling directly to the outside air, should also be provided as protection in case of failure of the electricity supply service. Consideration should be given to the dimensions of the projection room in order to provide normal operating safety factors for the projectionist. The room should be not less than 12 ft between front and rear walls, in order to have sufficient working and free walking space around all equipment. The rewind table should be located at the rear wall equidistant from the two projectors. The space between projectors should be sixty in. at the lens centers and there should be a clear space from the lens centers of 48 in. both to the right of the righthand projector and to the left of the lefthand projector. A modern design for the rewind table includes space beneath the table top for locating approved-type film containers, supported several inches above the floor. In order to deliver on the screen the high-quality performance expected from the projectionist, he must at all times, while on duty, be reasonably calm and alert both mentally and physically. These considerations, as well as those of common decency, call for providing adequate modern toilet facilities and a lavatory with both hot and cold running water in well-designed theater projection rooms. This brief review and discussion of present safety requirements in theater projection-room construction is intended to justify the conclusion that practically all of the requirements are in order regardless of the type of film used. They obviously must not be relaxed in any degree so long as there is a possibility that even small quantities of cellulose nitrate film may reach the theater, and this possibility may be with us for years to come. Entirely Samuel R. Todd: Safety Requirements in Projection 213