This European Standard specifies general requirements for the construction, testing and performance of electrically operated apparatus for the detection of combustible gases, designed for continuous operation in a fixed installation in domestic premises. The apparatus may be mains or battery powered. Additional requirements for apparatus to be used in recreational vehicles and similar premises are specified in EN 50194-2. NOTE 1 For caravan holiday homes EN 50194-1 applies. This European Standard specifies two types of apparatus to operate in the event of an escape of town gas, natural gas or 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 may actuate directly or indirectly a shut-off device and/or other ancillary device; - Type B apparatus - to provide a visual and audible alarm only. This European Standard excludes apparatus for the detection of toxic hazards of gases such as carbon monoxide (see EN 50291-1 and EN 50291-2). Apparatus complying with this standard is not considered suitable for industrial or commercial installations for which EN 60079-29-1 apply. NOTE 2 Apparatus tested in accordance with EN 60079-29-1 will not necessarily comply with this European Standard.