ISO 7240-7:2011 specifies requirements, test methods and performance criteria for point-type smoke detectors that operate using scattered light, transmitted light or ionization, for use in fire detection and alarm systems installed in buildings (see ISO 7240-1). ISO 7240-7:2011 also covers point-type smoke detectors that incorporate more than one smoke sensor operating on these principles. Additional requirements and test methods for such detectors are given. For the testing of other types of smoke detectors, or smoke detectors working on different principles, ISO 7240-7:2011 can be used only for guidance. Smoke detectors with special characteristics, developed for specific risks, are not covered. The national requirements for protection from radiation from detectors that contain radioactive materials differ from country to country and are not specified in ISO 7240-7:2011.