In Europe safety valves may only be utilized in the future if they fulfill the pressure vessel directive (DGRL) 97/23 EG. For that purpose they are classified into category IV in accordance with DGRL and a notified body verifies the fulfillment of the requirements of the DGRL in accordance with a selected procedure for the evaluation of conformity, also from DGRL. 

In a declaration of conformity by the manufacturer, which is enclosed with the delivery of the safety valve, the applied harmonized standards or other technical rules and regulations are indicated. This is actually the only way to recognize the basis of the CE-certification and the certified characteristics which can be derived from it. The presence of the CE-symbol on the nameplate alone is not significant.

A comparison between the applied harmonized EN-standards with the technical directives AD, TRD in the present contribution shows differences in the certified characteristics and the application of spring-loaded safety valves. This is explained by means of an example of a newly developed series of products. 

In addition the ASME-Code is taken into consideration as a comparison as it plays an important role outside Europe.