Fire Gas Detection

AbstractMost but not all fires emit smoke aerosols at some point during the combustion process. Therefore most conventional fire detectors are based on the detection of smoke by light scattering. As every fire is emitting specific gases it is reasonable to upgrade photoelectric fire detectors or even replace them for specific environments with gas sensor based technologies. In this paper we present some gas detection technologies which have the potential to be able to amend or replace existing systems for use especially in residential fire detectors. But here some restrictions apply when using gas sensors. Among others these are low cost, low power and long term requirements. We identified advantages but also some challenges of gas detection technologies by testing colorimetric gas sensors, gas sensitive field effect transistors and metal oxide sensors. As most technologies are not completely selective to the target gas and as there is not “the” fire with one specific mixture of combustion gases it is helpful to combine different sensing elements in sensor arrays where algorithms using pattern recognition methods like PLSDA, PCA etc. can be used to increase the prediction reliability and the false alarm robustness. Here we focused on typical combustion gases like CO, CO2, NO, NO2, NH3 and H2