This European Standard specifies the requirements and test methods for the design, manufacturing, safe operation and the rational energy usage for standard boilers and low temperature boilers (with """"boiler"""" in the sense of """"boiler body"""") from steel and cast iron to be equipped with separately marketed forced draught burners according to the relevant burner standards (for automatic forced draught burners for gaseous fuels see EN 676 and for atomising oil burners see EN 267) up to a nominal heat output of 10 MW. They are operated, either with negative pressure (natural draught boiler) or with positive pressure (pressurised boiler) in the combustio