The regulation is complicated and requires the necessary knowledge of the subject. The information in the links is interesting but that is as far as it goes. The limit of 0.5 bar is important. You can leave the rest to us. The customer specifies the pressure, temperature and medium, and the standard to be used.  Deprest decides if we work according to Category I, Category II, Category III or Category IV and does all the calculations. Your project is in good hands with us.


The Pressure Equipment Directive (PED) covers all pressurised containment systems such as vessels and piping, including fittings and fixings for flanges, etc. The term containment systems encompasses, among others, LPG installations, (steam) boilers and compressed air systems where pressure exceeds 0.5 bar. In particular, the Directive affects (suppliers to) the food processing, chemical and process industries.

The PED applies to the design, manufacture and conformity assessment of pressure equipment and assemblies with a maximum allowable pressure PS greater than 0.5 bar.

Examples include:

  • Pressure equipment such as pressure vessels, piping, safety accessories and elements attached to pressure equipment such as flanges, couplings, lifting lugs, etc.
  • Pressure vessels with one or more chambers.
  • Installation piping and components of piping systems, such as hoses, fittings, tubes, expansion joints, pipes etc.
  • Safety equipment such as safety valves, rupture disk safeties, buckling rods, CSPRS (Controlled Safety Pressure Relief Systems), pressure, temperature and level switches and SRMCR (Safety Related Measurement Control and Regulation) systems.
  • Pressure accessories.
  • Assemblies consisting of various pressure devices which a manufacturer integrates to create a functional whole.

Unlike with other directives, the CE marking is required on the individual parts and not on the entire installation.

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