Pressure Systems Safety Regulations 2000 (PSSR)

The duties imposed by PSSR relate to pressure systems for use at work and the risk to health and safety.

The aim of these Regulations is to prevent serious injury from the hazard of stored energy as a result of the failure of a pressure system or one of its component parts.

Before using any qualifying pressure equipment (new or otherwise), a written scheme of examination (WSE) must be in place, and an examination undertaken.

Pressure systems are defined as:

  • a system comprising one or more pressure vessels of rigid construction, any associated pipework and protective devices
  • the pipework with its protective devices to which a transportable pressure receptacle is, or is intended to be, connected
  • a pipeline and its protective devices

A relevant fluid is:

  • steam at any pressure
  • compressed or liquefied gas, including air, at a pressure greater than 0.5 bar above atmospheric pressure; pressurised hot water above 110 °C
  • a gas dissolved under pressure in a solvent (acetylene)

Relevant fluids do not include hydraulic oils. Hydraulic systems, while using high pressures, do not store energy in the system and so are not covered by this legislation.

The PSSR Approved Code of Practice (ACOP), Safety of pressure systems (L122), will help you determine which regulations (if any) apply.


There are many exceptions to PSSR, including:

  • a pressure system which forms part of, or is intended to form part of, a weapons system
  • any pressure system which is the subject of a research experiment
  • any tyre used or intended to be used on a vehicle

25 complete exceptions are detailed in PSSR Schedule 1 Part 1.

3 partial exceptions are detailed in PSSR Schedule 1 Part 2.

If in doubt, the useful and instructive ACOP Safety of pressure systems provides additional information and advice.

Certificate of Exemption

HSE has published an exemption certificate for any pressure system forming an enclosure for high voltage equipment.

The difference between a pipeline and pipework

The easiest way to distinguish between the 2 terms is to remember that pipelines cross boundaries and pipework does not (except where there is a common supply to a number of units). The terms also include associated protective devices, valves, compressors and so on.

The PSSR ACOP Safety of pressure systems provides useful definitions of pipework and pipelines as these can vary between different regulations (specifically PSSR, PE(S)R and the Pipeline Safety Regulations 1996).

Who has duties under PSSR?

Employers (also known as 'dutyholders'), including:

  • the owner of a mobile system, that is, one that can be easily moved, such as an air compressor taken from site to site
  • the user of an installed system, that is, one that is not a mobile system, such as a steam boiler

The user of hired or leased equipment should make sure that the WSE is in place and that the certificate of examination is also current.

PSSR Schedule 2 allows a supplier of an installed system to assume responsibility in writing for the WSE, the operation, the maintenance and the record keeping.

Competent person

In general terms, the role and responsibilities of the competent person can be summarised as follows:

  • carry out examinations in accordance with the WSE including:
    • review WSE and confirm it is suitable
    • produce a written report for each examination
    • notify user/owner of repairs required
    • identify action in case of imminent danger
    • agree postponements of examination, where appropriate
  • draw up or certify written schemes of examination

An important feature of the in-house competent person is that they should be independent from the operating functions of the organisation, and they must have sufficient authority to stop the use of the pressure equipment should the need arise.

For more detail about the role and responsibilities of the competent person see the Approved Code of Practice (L122) Safety of pressure systems, particularly paragraphs 28 to 34 and 100 to 102.

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Updated: 2023-11-14