This part of ISO 7240 specifies requirements, test methods and performance criteria for point fire detectors using electro-chemical cells that operate using carbon-monoxide detection principles for use in fire detection and alarm systems installed in buildings (see ISO 7240-1).For the testing of other types of CO fire detectors working on different principles, this part of ISO 7240 can be used only for guidance. Fire detectors with special characteristics and developed for specific risks are not covered by this part of ISO 7240.