Skip to main content

A simple pressure vessel is any welded vessel intended to be subjected to an internal gauge pressure greater than 0.5 bar and to contain air or nitrogen and which is not intended to be fired (heating).

Free movement of simple pressure vessels

Simple pressure vessels are vessels produced in series and having the following features:

  • the vessels are welded and intended to be subjected to an internal gauge pressure greater than 0.5 bar and to contain air or nitrogen, and are not intended to be fired;
  • the parts and assemblies contributing to the strength of the vessel under pressure are made either of non-alloy quality steel or of non-alloy aluminium or non-age hardening aluminium alloys;
  • the vessel is made of either of a cylindrical part and a dished or two dished ends revolving around the same axis;
  • the maximum working pressure of the vessel does not exceed 30 bars and the product of that pressure and the capacity of the vessel does not exceed 10 000 bar.L;
  • the minimum working temperature is no lower than – 50 °C and the maximum working temperature is not higher than 300 °C for steel and 100 °C for aluminium or aluminium alloy vessels.

When placing on the market vessels of which the product of pressure and volume exceeds 50 bar.L, manufacturers shall ensure that they have been designed and manufactured in accordance with the essential safety requirements. When placing on the market their vessels of which the product of pressure and volume is 50 bar.L or less, manufacturers shall ensure that they have been designed and manufactured in accordance with the sound engineering practice in one of the Member States.

For vessels of which the product of pressure and volume exceeds 50 bar.L, manufacturers shall draw up the technical documentation and carry out the relevant conformity assessment procedure. Where compliance of a vessel of which the product of pressure and volume exceeds 50 bar.L with the applicable requirements has been demonstrated by that procedure, manufacturers shall draw up an EU declaration of conformity and affix the CE marking and the required data about the vessel. Manufacturers shall retain the technical documentation and the EU declaration of conformity for 10 years after the vessel has been placed on the market. Vessels are placed on the market and/or in service only if they fulfil the requirements of the Rules on simple pressure vessels, if they are appropriately installed and maintained and only used for the intended purpose.