This European Standard specifies the requirements and test methods for the construction, safety, marking and rational use of energy of gas-fired insets for heating more than one room that are intended to be built into a casing made from brickwork or similar material. This European Standard is intended to be used in conjunction with EN 613:2000. This European Standard is applicable to type B11BS insets burning gas: that incorporate an atmospheric burner; that are installed directly to an open flue or to a device to evacuate the products of combustion; that have a nominal heat input not exceeding 20 kW (based on the net calorific value). In addition, this European Standard is also applicable to insets for heating more than one room which have a live fuel effect. This European Standard is not applicable to: open fronted appliances as specified in EN 13278; decorative fuel effect appliances as specified in EN 509; convection heating appliances as specified in EN 613; catalytic combustion appliances; appliances in which the supply of combustion air and/or evacuation of products of combustion is achieved by mechanical means as specified in EN 1266; warm air heaters (which are subject of CEN/TC 180). This European Standard is only applicable to insets which are intended to be type tested.