the invention relates to a device equipped with a burner for combusting a fuel / oxidant mixture inside a combustion chamber in which a material is provided that endures a maximum temperature . the inventive device also comprises one or more supply lines for the fuel as well as for the oxidant which are provided for supplying the same into the combustion chamber . the inventive device is characterized in that it is designed for carrying out a combustion with a combustion temperature of the fuel / oxidant mixture that exceeds the maximum temperature . the device is designed in such a way that at least one additional supply line is provided via which an additional gas having , in particular , a low calorific value can be supplied to the combustion chamber . said additional gas enables the temperature during combustion to be lowered to a value that is less than the maximum temperature .