ISO 7240-8:2015 specifies requirements, test methods, and performance criteria for point multi-sensor fire detectors that incorporate at least one carbon monoxide (CO) sensor 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 part of ISO 7240 is only to be used for guidance. CO and heat multi-sensor fire detectors with special characteristics and developed for specific risks are not covered by this part of ISO 7240.