Development and field deployment of a mid-infrared CO and CO 2 dual-gas sensor system for early fire detection and location.

In order to realize early fire detection and location, a mid-infrared carbon monoxide (CO) and carbon dioxide (CO) dual-gas sensor system was developed, which mainly includes a gas pretreatment module, a CO sensor module, a CO sensor module, and a laptop monitoring platform. CO 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 CO sensor modules was measured to be ∼ 30 s at a flow rate of 1 L/min, and the limits of detection (LoD) of CO 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 CO 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 CO (C(CO)/C(CO)) 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.