PSSR — Pressure Systems Safety Regulations 2000
Your complete guide to understanding PSSR requirements
PSSR exists 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. This guide covers who the regulations apply to, what counts as a pressure system, the Written Scheme of Examination, and the role of the competent person.
What is PSSR?
The Pressure Systems Safety Regulations 2000 (PSSR) are UK health and safety regulations that aim 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. They replaced the earlier Pressure Systems and Transportable Gas Containers Regulations 1989.
Unlike LOLER and PUWER which focus on equipment use and operations, PSSR is specifically concerned with the integrity of systems that contain relevant fluids — steam, compressed gases, pressurised hot water, and dissolved gases. The key mechanism of PSSR is the requirement for a Written Scheme of Examination (WSE) to be in place before a pressure system is operated.
The regulations define "pressure system" as a system comprising one or more pressure vessels of rigid construction, any associated pipework and protective devices, the pipework with protective devices to which a transportable pressure receptacle is connected, and a pipeline and its protective devices.
Relevant Fluids
PSSR only applies to systems containing the following types of fluid:
At any pressure
Including air, exceeding 0.5 bar above atmospheric pressure
Above 110°C
Gas dissolved in a solvent under pressure (e.g. acetylene)
What is NOT Covered
Hydraulic oil systems are generally not covered as they use an incompressible fluid that does not store energy in the same way. PSSR also lists 25 complete exceptions (Schedule 1 Part 1) including weapons systems, certain research experiments, and vehicle tyres.
Who Has Duties Under PSSR?
PSSR duties fall on different parties depending on whether the system is installed, mobile, or hired:
Equipment Owners
For mobile pressure systems such as portable compressors and mobile steam boilers, the owner is the dutyholder.
Equipment Users
For installed pressure systems such as fixed steam boilers, air receivers, and autoclaves, the user or operator of the premises is the dutyholder.
Hirers and Lessees
If you hire or lease pressure equipment, you are the dutyholder for the duration of the hire. You must verify examination documentation is current.
Suppliers
In some cases, the supplier may assume responsibility for the equipment if they have agreed to do so in writing, as set out in Schedule 2 of the regulations.
The Written Scheme of Examination
The Written Scheme of Examination (WSE) is the cornerstone of PSSR compliance. It is a document that must be in place before a pressure system is operated. The WSE identifies:
What to Examine
Every part of the pressure system that needs to be examined, including vessels, pipework, safety valves, gauges, and any other protective devices.
Nature of Examination
The type of examination required for each part — this may include visual inspection, non-destructive testing, pressure testing, or operational checks of safety devices.
Examination Intervals
The maximum interval between examinations for each part. These are set by the competent person based on the system type, age, condition, and operating environment.
Preparatory Measures
Any preparatory measures the user must take before the examination — such as depressurising, draining, cleaning, or providing access to specific parts of the system.
The Competent Person
PSSR requires the Written Scheme of Examination to be drawn up or certified as suitable by a competent person, and all examinations to be carried out by a competent person.
The competent person must:
- Review and confirm the suitability of the Written Scheme of Examination
- Carry out examinations in accordance with the WSE
- Produce a written report of every examination
- Notify the user of any repairs or modifications required
- Identify situations of imminent danger and require equipment to be taken out of service
- Maintain independence from operational functions to ensure impartial judgement
- Possess authority to recommend stopping the use of equipment if necessary
Imminent Danger
If the competent person identifies imminent danger during an examination, they must notify the user immediately and the system must be taken out of service until the issue is resolved.
Equipment Covered by PSSR
Common types of pressure system equipment that require examination under PSSR:
Official Source
This guide is provided for general information only. The key reference document is the Approved Code of Practice (L122) "Safety of pressure systems". For full regulatory text and HSE guidance, visit:
HSE — PSSR GuidancePSSR is Independent of LOLER and PUWER
Unlike LOLER (which overlaps with PUWER for lifting equipment), PSSR applies independently to pressure systems. A piece of equipment may be covered by PSSR alone, or in some cases by both PSSR and PUWER if it is also considered "work equipment" (which most pressure systems are).
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