"...fire gutted the projection room of the theater"
Sorry Mike, not found anything quite that bad on this end. Incandescent {glowing} plug fuses probably would have preoccupied me too. If you could see “red” under those conditions, I’d bet the panel was “slugged” with copper pennies behind the plug fuses. I can’t imagine the fusible alloy maintaining circuit continuity [internal to the fuse itself] survive being heated to that extent . I have a “laurel wreath” [ie, old] penny with melted—once-liquid—arc marks that I found in an attic from which I exited rather quickly. The back of its porcelain cutout had been hot enough to melt and cause to drool the ceramic-based insulating cement behind the cutout’s screwshell.
Your account of the fire incident is even more unusual, in that old projection rooms were most often made as fire- and ”bullet”-proof as could be. {I’m certain in virtually all cases that meant a pile of asbestos used in the room’s construction.} Earlier in the twentieth century, the rationale behind all the extra efforts at protection of this type of room was that they routinely stored photographic film made from cellulose nitrate, which is roughly equivalent to gunpowder in energy release during deflagration following ignition.
“Unless stored at a very low temperature, cellulose nitrate motion picture and still photographic film (also known as nitrate) self-destructs at an unpredictable rate over time. As it deteriorates, nitrate gives off acidic by-products (nitric oxide, nitrogen dioxide). These acidic gases are deep lung irritants. Repeated exposure may cause eye irritation, rashes and sores on the face and skin, vertigo, nausea, headaches, swollen glands, and respiratory irritation. By-products from nitrate film also damage surrounding museum materials causing embrittlement of paper and film and cumulative damage to many organic materials and metals. Deteriorated nitrate film is highly flammable and can burn under water. Once ignited, nitrate fires are almost impossible to put out. The toxic gases produced by burning nitrate are lethal. Nitrate should not be stored in general museum, archival, or office spaces.” http://www.cr.nps.gov/museum/publications/conserveogram/14-08.pdf
