Development and field deployment of a mid-infrared CO and CO₂ dual-gas sensor system for early fire detection and...

In order to realize early fire detection and location, a mid-infrared carbon monoxide (CO) and carbon dioxide (CO₂) dual-gas sensor system was developed, which mainly includes a gas pretreatment module, a CO₂ sensor module, a CO sensor module, and a laptop monitoring platform. CO₂ and CO absorption lines located at 4.26 μm and 4.66 μm, respectively, were selected to ensure good selectivity of the sensor system. A series of experiments were carried out to evaluate the sensor performance. The 10-90% response time of the CO and CO₂ sensor modules was measured to be ∼ 30 s at a flow rate of 1 L/min, and the limits of detection (LoD) of CO₂ and CO were assessed to be 5.66 parts per million by volume (ppmv) and 0.94 ppmv, respectively, when the averaging time was 0.25 s. According to the correlation between CO₂ and CO concentration in the early fire stage, a method of early fire detection was studied and proposed using the normalized concentration ratio between CO and CO₂ (C(CO)/C(CO₂)) as the key alarm parameter. Based on gas turbulent diffusion (GTD) model combined with particle swarm optimization (PSO) algorithm, a mobile early fire location method was presented. Correlative experiment results verified that the reported sensor system has a good performance for early fire detection and location.