Monitoring of Eucalyptus globulus tissue thermal degradation by semi-conductor metal-oxide sensors for early fire detection in eucalypt forests

Volatile organic compound (VOC)-based fire-risk assessment systems for woodland fires can shorten the time between a fire outbreak and the arrival of fire crews. This can prevent the development of crown fires, which are harder to control than ground fires. Semi-conductor metal-oxide gas sensors possess good technical properties for VOC detection. In this study, the VOC emissions of heated lignocellulose biomass (Eucalyptus globulus) was analysed by gas chromatography–mass spectrometry (GC-MS). Three semi-conductor metal-oxide gas sensors were calibrated to eucalyptol, furfural, α-pinene and 2-methoxyphenol. Among the 20 quantified VOCs, eucalyptol and furfural showed the highest emission rates. The sensors online monitored the temperature-dependent VOC pattern generated by the pre-ignition, at ignition and post-ignition heating stages. The feasibility of such gas sensors for early fire detection is discussed.