| 摘要 |
PROBLEM TO BE SOLVED: To provide a fire decision device which effectively determines a fire and operates with low power consumption, and a fire alarm using the fire decision device. SOLUTION: The fire decision device includes a smoke sensor 4, a CO sensor 3, a calculation means 2 of calculating a smoke density gradient Gs, a smoke density difference maximum value ¾d¾max, and a CO density gradient Gco, and an elapsed time measuring means 2 of measuring an elapsed time Ts until smoke density reaches first set smoke density and second set smoke density, and determines a fire on the basis of the smoke density gradient Gs, the smoke density difference maximum value ¾d¾max, the elapsed time Ts, and the CO density gradient Gco. Further, the fire decision device includes a decision operation stop means of stopping the operation for determining a fire when the smoke density exceeds the first set smoke density and then the smoke density becomes below the first set smoke density without exceeding the second set smoke density a predetermined number of times or more within a predetermined period. COPYRIGHT: (C)2010,JPO&INPIT
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