• Pressure Vessel, Piping, Safety accessoires, Pressure-retaining accessoires, Assemblies

What are Pressure Vessels?

Pressure vessels are closed vessels whose internal pressure is different from the ambient pressure.

The Pressure Equipment Directive (PED) defines the following types of pressure equipment:

Vessels, piping, safety accessories, and pressure-retaining components. Where applicable, pressure equipment includes all elements attached to pressurized parts, such as flanges, nozzles, couplings, supports, lifting lugs, etc.

A closed component that is designed and built to contain fluids under pressure including its direct attachments up to the coupling point connecting it to other equipment. A vessel may be composed of more than one pressure chamber.

Piping components intended for the transport of fluids, when connected together for integration into a pressure system. Piping includes in particular a pipe or system of pipes, tubing, fittings, expansion joints, hoses, or other pressure-bearing components as appropriate. Heat exchangers consisting of pipes for the purpose of cooling or heating air shall be considered as piping.

Safety accessories
Devices designed to protect pressure equipment in case the allowable limits are exceeded. Such devices include:

  • Devices for direct pressure limitation, such as safety valves, bursting disc safety devices, buckling rods, and controlled safety pressure relief systems (CSPRS)
  • Limiting devices, which either activate the means for correction or provide for shutdown or shutdown and lockout, such as pressure switches or temperature switches or fluid level switches and 'safety related measurement control and regulation (SRMCR)' devices

Pressure-retaining accessories
Devices with an operational function and having pressure-bearing housings.

Several pieces of pressure equipment assembled by a manufacturer to constitute an integrated and functional whole.