ISSUES OF DESIGN AND PRODUCTION IMPLEMENTATION OF GAS-SENSING FIRE DETECTORS

The issues of design and production implementation of gas-sensing fire detectors, combination fire detectors, are considered in this paper. It is shown that gas-sensing fire detectors with a carbon monoxide channel are devices that ensure fire detection during the early stages of its development (the stage of smoldering of a material). However, the certification procedure for gas-sensing fire detectors is unnecessarily complicated and differs considerably from that for gas alarms, even though the two serve virtually the same purpose: to determine the level of indoor gas contamination. Consequently, the testing methods for gas-sensing fire detectors should be converged as much as possible with those for other types of gas analysis devices, such as gas analyzers and gas alarms. Moreover, the technical parameters of gas-sensing fire detectors allow them to be used for evaluating the level of indoor contamination by toxic, flammable, and explosive gases and fumes (provided that the channel for flammable gases is used) as well as for preventing human gas poisoning and improving fire and explosion safety of the premises. In other words, gas-sensing fire detectors are essentially dual-purpose devices and their additional certification as gas alarms will provide an opportunity to install, instead of two devices — the fire detector and gas alarm, just one device — the gas-sensing fire detector, using a single monitoring and receiving system, which offers an additional economic benefit. Advantages and disadvantages of gas-sensing fire detectors are shown. The authors believe that the combining of thermal and gas channels in one fire detector allows to comprise all types of fire and is the most effective for their detection in terms of cost and quality. Test results for the prototype combination detector SPKGT-01, based on the heat sensor (thermistor), and the semi-conductor sensor TGS 2442 of carbon monoxide are provided. Recommendations on how to simplify the testing methods and current testing equipment for gas-sensing fire detectors are given.