ISO 12239:2003 specifies requirements, test methods, performance criteria, and manufacturer's instructions for smoke alarms (including those with optional features) that operate using scattered light, transmitted light, or ionization, and are intended for household or similar residential applications. Smoke alarms with special characteristics and developed for specific risks and devises intended for incorporation in systems using separate control and indicating equipment are not covered by ISO 12239:2003. For the testing of other types of smoke alarms, or smoke alarms working on different principles, this document should be used only for guidance.