Guide
Written scheme of examination for compressed air: what PSSR requires
Updated
This is the part of compressed air that is genuinely a legal duty rather than good practice, and it is the part most sites are vaguest about. It is also short enough to understand in one sitting.
Why your compressor room is a pressure system
The Pressure Systems Safety Regulations 2000 apply to pressure systems used at work. HSE defines a relevant fluid as including compressed or liquefied gas, including air, at a pressure greater than 0.5 bar above atmospheric pressure, and a pressure system as one or more pressure vessels of rigid construction with associated pipework and protective devices (HSE, pressure systems). A receiver, the pipework hanging off it and the safety valves protecting it are exactly that.
What the regulations actually require
- A written scheme of examination (regulation 8)
- A scheme covering the protective devices, every pressure vessel and the relevant pipework, drawn up or certified as suitable by a competent person. HSE is explicit that before using qualifying pressure equipment, new or otherwise, the scheme must be in place and an examination undertaken.
- Examination in accordance with the scheme (regulation 9)
- The system is examined as and when the scheme says, by a competent person, who reports in writing and states when the next examination is due. The scheme sets the interval, not the regulations.
- Operation, maintenance and records (regulations 11, 12 and 14)
- Safe operating limits established, the system properly maintained, and records kept. These sit alongside the examination, not instead of it.
- Action in case of imminent danger (regulation 10)
- Where an examination finds imminent danger, the competent person must report it and the system must not be used until the defect is remedied.
The full list of regulations is on legislation.gov.uk, and the Approved Code of Practice, Safety of pressure systems (L122), is the guidance a competent person will be working to.
Who holds the duty
- The user of an installed system. The fixed compressor and receiver in your plant room is your duty as the employer using it.
- The owner of a mobile system. HSE gives the example of an air compressor taken from site to site: there the duty sits with the owner.
- Hired or leased plant. The user should make sure the written scheme is in place and the certificate of examination is current before the machine is put to work.
- Suppliers, by written agreement. PSSR Schedule 2 allows a supplier of an installed system to take on responsibility in writing for the scheme, operation, maintenance and record keeping.
What makes someone a competent person
HSE summarises the competent person's role as drawing up or certifying written schemes, carrying out examinations in accordance with the scheme, reporting in writing, notifying repairs, identifying imminent danger and agreeing postponements where appropriate. An in-house competent person must be independent of the operating functions of the organisation, and must have enough authority to stop the equipment being used. In practice most sites buy this in, often from an engineering inspection body rather than from the same firm that services the machine.
Servicing and examination are different purchases. A service engineer changing filters and oil is not, by that act, discharging your PSSR duty. When you ask for quotes, ask for both, and ask who certified the scheme.