Fire detection and alarm system - uses detectors for fluid pressure variation in enclosure and has one responsive to pressure variation

摘要

The system uses an enclosure (5) fitted with equipment for pressurising a fluid contained in the enclosure. The pressure introduced is greater than ambient when there is no fire. The system has detectors (6, 7) including a pressure variation detector. These detectors react, to control the operation of a fire alarm, to any pressure which varies with at least a determined rate. A min. pressure detector reacts to control alarm operation for any fall in pressure below a min. safe operating value lower than the normal pressure in the absence of fire.