| 摘要 |
PROBLEM TO BE SOLVED: To provide a composit fire alarm apparatus which detects a fire early in a smoldering fire in which a smoke density and a CO density increase gradually, but does not operate immediately to a non-fire phenomenon in which a smoke density and a CO density increase suddenly. SOLUTION: When a smoke density in a smoke sensing part 3 reaches 2.5%/m, a microcomputer 2 of the fire alarm apparatus 1 measures the elapsed time from that point of time to the point of time when the smoke density reaches 5%/m, sets an accumulation time in inverse proportion to the measured elapsed time, sets an operating level of the smoke sensing part 3 and that of a CO sensing part 4 at the time of detection according to the elapsed time, and judges whether the operating levels are higher than preset threshold values. If the operating levels are higher than the threshold values, when this state continues until the accumulation time elapses, the microcomputer 2 discriminates a fire alarm. If the operating levels become lower than the threshold values before the accumulation time elapses, the microcomputer 2 discriminates a non-fire alarm. COPYRIGHT: (C)2006,JPO&NCIPI
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