Pressure Equipment and Materials Technology

What is Pressure Equipment Directive 97/23/EC ?

The Pressure Equipment Directive (PED) is an EU product directive that is mandatory since 30 May 2002. The PED is a guideline for the design and manufacture of pressure equipment with maximum allowable pressure greater than 0.5 bar. Products covered include pressure vessels, heat exchangers, steam boilers, pipelines, storage tanks, pressure relief devices, valves, regulators and other pressure equipment.

Previously, each European Member State had its own pressure equipment regulations and the different regulations created a barrier to trade between member states. The PED harmonised applicable standards and regulations within the whole European Union, and resulted in enhanced safety during the manufacture and use of pressure equipment.

The directive classifies pressure vessels and pressure assemblies into four categories depending on the amount of potential energy the vessels or assembly can store and the fluid that is handled. The potential energy is a product of the vessel volume and the maximum allowable working pressure. Classification of pressure equipment depends also on the safety function of the particular pressure equipment within a pressure assembly.

The PED addresses the issue of quality assurance during the manufacture of pressure equipment or assembly of pressure assemblies through use of conformity assessment modules. Conformity assessment modules are quality systems that ensure that a manufacturer addresses issues like design, manufacture, documentation and quality assurance during the manufacturing phase of pressure equipment. For vessels and equipment with low risk (potential energy), manufactures can implement conformity assessment without any input from a third party and demonstrate conformity by affixing a CE mark on the product. For pressure equipment, of a more hazardous nature, conformity assessment modules compel the use of third party conformity assessment bodies for assuring conformity. CE marking can only be affixed with the consent of the assessing conformity assessment body.