DUAL-LOOP SMOKE AND FIRE DETECTOR SYSTEM AND METHOD

摘要

A hazardous condition detection system (150) for an enclosure (105) includes at least three detectors (110-119) and a controller (130). Each detector is mounted within the enclosure. Each detector is configured to output a signal representing a first lower level of severity (a pre-alarm threshold) and a signal representing a second higher level of severity (an alarm threshold). The controller monitors the operational status of each of the detectors. In a first mode when all the detectors are operational, the controller generates an alarm signal when at least two detectors output a signal at the alarm threshold level. In a second mode when at least one of the at least three detectors are inoperative and at least two of the at least three detectors are operational, the controller generates an alarm signal when one detector outputs a signal at the alarm threshold level and another detector outputs a signal at the pre-alarm threshold level.