International projectionist (Jan-Dec 1957)

FIG. 3. Simulated fire at acetate film. projection on Nitrate film during same situation as in Fig. 3. simulated of the safety film on the ground was consumed, the flames did not carry up the streamers from the bottom magazine. Figure 4 is the same test repeated but this time nitrate film was used in both the top and bottom magazines with the film streamers in approximately the same location. The loose nitrate film on the ground was set on fire and immediately the film in the lower magazine ignited and burned with considerable intensity. The streamers from the top magazine burned to the opening in the bottom of the magazine, setting off the roll in the top magazine which burned completely and with considerable intensity. It was observed that the intensity of the flames in both top and bottom magazines was sufficient to melt the white metal holders for the film rolls and to warp and bend the magazines. Using a mock 35-mm process machine dryer section constructed of twoby-fours with Transite sides, top, bottom, and back with center partitions and doors made of acetate sheeting for visibility, acetate film was threaded throughout the machine to a windup roll on the outside. Film was looped from the windup roll down to the ground as could occur from a nonattended windup. This material was ignited with a wad of excelsior and the film on the ground burned without carrying up to the windup roll. The burnout time was 170 sec. Nitrate Goes in 55 Sec. After the acetate was removed from the machine dryer section, the machine was threaded with 35-mm nitrate film in the same manner as the previous test. The nitrate film was ignited and in 55 sec the entire quantity of nitrate film was consumed. The fire burned from the loose pile on the ground up to and ignited the windup roll following the film strip from the machine to the roll and igniting the material looped inside the first section of the machine. It burned rapidly inside carrying through to the second section which burned almost immediately, and after the pressure built up inside the machine, the doors blew open and the heat was sufficient to melt some of the acetate on the doors. It was interesting to note that the acetate material on the doors did not ignite and burn. Approximately 40 lb. of acetate film was placed in a loose pile inside an enclosure approximately eight feet wide with an open face. The acetate film was ignited and the fire allowed to burn for about two minutes. A fire fighter using a dry chemical extinguisher readily extinguished the burning film. Another test fire was ignited with 40 lb. of nitrate film substituted for the acetate. Here the fireman used a water spray nozzle to attempt extinguishment. The flames did not appear to diminish in intensity despite the application of water fog, and when the fire was finally extinguished practically all the nitrate film in the center of the pile had been consumed. Film Overheating Report Set for issuance this fall, a report on the various factors affecting film overheating is being prepared by the Film Projection Practices Committee of the SMPTE. Due to the increasing requirements for higher light intensity, all operating personnel should be acquainted with these factors. The report group, under the chairmanship of Herb Behrens of DuPont intends the report to be in shape by June. ********* BE SURE YOUR NEW PROJECTION ARC LAMPS have an automatic crater positioning system that maintains a brilliant WHITE light at the screen at all times. ^ This is Another EXCLUSIVE FEATURE of the New Strong U-H-l PROJECTION ARC LAMP INTERNATIONAL PROJECTIONIST • MARCH 1957 31