scope:

Specifies general requirements for the construction, testing and performance of electrically operated, combustible gas detection apparatus, designed for continuous operation in a fixed installation in domestic premises. The apparatus may be mains or battery powered. This standard specifies two types of apparatus to operate in the event of an escape of town gas, natural gas of liquefied petroleum gas (LPG): Type A apparatus - to provide a visual and audible alarm and an executive action in the form of an output signal that can actuate directly or indirectly a safety shut-off device or other ancillary device. Type B apparatus - to provide a visual and audible alarms only.