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Show Spontaneous Fires Puzzle Scientists What causes oily rags tucked away in a closet to catch fire all toy themselves and what can toe done to control this "spontaneous combustion?" Researchers at the National Eoard of Fire Underwriters and the National Bureau of Standards are trying to find the answers to those two questions. Some fairly common substances heat up by themselves under certain cer-tain conditions, and frequently cause serious fires. Unslaked-lime, although it will not bum, heats up when it gets moist and then sets fire to any nearby combustible combus-tible material. Oily rags will heat up at ordinary or-dinary room temlperaiture, and burst into flame. This is the result re-sult of oxidation. Linseed, soya, cotton, olive, and grape oil will ignite spontaneously, and even iron will do so when it is reduced to powder. Charcoal and soft coal are also "self heating." Hay and igrain still mystify the scientists. Why does a stack of hay suddenly catch fire without any outside help? One theory is that microbes in the hay soak up a lot of oxygen, causing a chemical chemi-cal reaction. This chemical reaction reac-tion produces heat and the farmer far-mer loses his pile of hay . . . and maybe the barn it's stored in. The scientists, still studying the mysterious process, have this advice for farmers: Cure the hay before putting it in the barn, and keep a thermometer stuck in the hay. When the temperature reaches 212 degrees, call the fire department. To ordinary householders, the experts suggest: Throw away oily rags. Don't store combustible combus-tible materials in attics. Keep oily mops where air can circulate around them freely, or, better still, keep them in metal cans. |