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.