Written Schemes for Pressure Systems
A written scheme of examination sets out which parts of a pressure system must be examined, how, and how often. We prepare compliant schemes for pressure vessels and systems under the Pressure Systems Safety Regulations 2000.
About written schemes for pressure systems
Under the Pressure Systems Safety Regulations 2000, a relevant pressure system must not be operated until a suitable written scheme of examination is in place. The duty to have one sits with the user of an installed system, or the owner of a mobile one, and the scheme itself must be drawn up, or certified as suitable, by a competent person.
The scheme is the document that defines the examination regime for the system. It identifies every pressure vessel and protective device, and any part of the pipework that could give rise to danger if it failed, then specifies the nature of the examination for each item and the maximum interval between examinations.
At Vertek we prepare written schemes for pressure vessels and complete pressure systems, working from the design information, the operating conditions and the safe operating limits. The result is a scheme that meets the regulatory duty and gives a clear, workable basis for the examinations that follow.
What the scheme covers
A written scheme for a pressure system identifies the examinable items and sets the terms of their examination. A typical scheme addresses:
- Every pressure vessel within the system
- All protective devices, including safety valves and bursting discs
- Parts of pipework whose failure could be dangerous
- The nature of the examination required for each item
- The maximum interval between examinations
- The measures needed to prepare the system for safe examination
- Examination before first use where appropriate
- The safe operating limits the scheme is based on
Why the scheme comes first
A legal precondition
A relevant pressure system must not be operated until a suitable scheme is in place, so the scheme is the starting point for lawful operation.
Certified by a competent person
Drawing up or certifying the scheme calls for the skills, knowledge and experience the regulations set out for a competent person.
Scope matched to risk
The items included and the intervals set reflect the degradation mechanisms the system is actually exposed to, not a generic template.
A basis for examination
A clear scheme makes each in-service examination straightforward to plan, prepare for and carry out.
The scheme document you receive
You receive a written scheme of examination that lists the examinable items, the nature of the examination for each, and the maximum interval between examinations, together with the preparation measures needed to examine the system safely.
The scheme records the safe operating limits it is based on and the competent person's certification that it is suitable for the system. It is written so that the person carrying out the examinations, and the duty holder responsible for the plant, can both see exactly what is required and when.
Where the examinations themselves are also carried out by Vertek, the scheme and the resulting reports are produced by people who understand the plant first hand, which keeps the findings and any recommendations grounded in the real condition of the system.
Who needs a written scheme
The Pressure Systems Safety Regulations 2000 apply to systems containing a relevant fluid. Broadly, this covers systems where the product of the pressure and the internal volume of the pressure vessels is at or above 250 bar litres, and any system containing steam. Relevant fluids include compressed or liquefied gases and pressurised hot water above 110 degrees Celsius, but not hydraulic oils. Where a system falls within scope, a suitable written scheme of examination must be in place before it is operated.
Related inspection services
Need a written scheme for a pressure system?
Speak with our team about drawing up or certifying a scheme of examination under PSSR.