The requirements and test methods for thermostatic radiator valves included in this standard summarize the specifications of respective national standards which had been valid up to now. The experience member countries gained from these national standards contributed to updating. In comparison with the replaced national standard DIN 3841 part 2 the requirements on mechanical properties, on operating characteristics and on endurance are more stringent. The standard is complemented by a certification scheme agreed by CEN which allows to give evidence of the conformity with the standard by the CEN mark.