A prediction model of point-type smoke detector response signal variation in high altitude area

The response signal trends of ordinary ionization and photoelectric detectors under high altitude area were predicted using a simple model. The analysis results showed that the response trend varied with the pressure at 2^nd power law for ionization detector, and 4^th power law for photoelectric detector, which indicates that the signal performance of point-type smoke detector decreased with increasing altitude based on the same test fire source, and the main reason is the influence of air pressure on the burning behavior of material. Pool fires experiments were conducted in Hefei and Lhasa by ISO detector test method, TF 4 and TF 5 experimental results was consistent with the theory well, it means, to achieve the same ability or performantce as normal pressure condition, the engineering parameters such as alarm threshold of smoke detector should be adjusted properly for low pressure condition. While error appeared during small size pool fire test for the weaken of smoke accumulation under ceiling. This simple prediction model could be as a reference in the design of smoke detector for high altitude area.