A fire detection and fire alarm system is required to function satisfactorily not only in the event of a fire, but also during and after exposure to conditions such as corrosion, vibration, direct impact, indirect shock and electromagnetic interference.
Carbon monoxide (CO) fire detectors can react promptly to slow, smouldering fires involving carbonaceous materials. Although in the majority of fires the products of combustion are transported by convection, the gaseous nature of CO means that it also diffuses and, particularly in low energy fires, it can move ahead of the smoke plume and thus provide earlier detection.
Conversely, CO fire detectors alone might not react quickly to flaming fires and the addition of a heat sensor provides better detection to a broader spectrum of fires.
BS ISO 7240-8:2007 specifies requirements, test methods and performance criteria for point multi-sensor fire detectors that incorporate an electrochemical cell for sensing carbon monoxide (CO) in combination with one or more heat sensors, for use in fire detection and alarm systems installed in buildings (see ISO 7240-1).
For the testing of other types of CO multi-sensor fire detectors, or CO and heat multi-sensor fire detectors working on different principles, this Standard can be used for guidance. CO and heat multi-sensor fire detectors with special characteristics and developed for specific risks are not covered by this Standard.
