Written Schemes of Examination: PSSR 2000

A Written Scheme of Examination (WSE) is a legal requirement under the Pressure Systems Safety Regulations 2000 (PSSR 2000) for any compressed air system where the product of maximum allowable pressure and vessel volume meets or exceeds 250 bar litres. A standard compressed air receiver (270 litres at 10 bar) is already well above this threshold. The WSE defines what must be examined, how it must be examined, and how often, and it must be in place before the system is operated.

ALS Industrial Services Ltd coordinate and support the production and maintenance of Written Schemes of Examination for compressed air, nitrogen and process water chiller systems. We work alongside an accredited competent person to ensure the scheme reflects the actual system accurately and that the examination programme is practical to implement.

What a Written Scheme of Examination covers

A WSE must identify every pressure-bearing item in the system that is subject to examination and specify, for each one:

• The method of examination required (visual inspection, hydraulic pressure test, ultrasonic wall thickness measurement)
• The maximum interval between examinations
• The safe operating limits for the item
• Any preparatory work required before examination (isolation, depressurisation, access arrangements)

Items typically covered in a compressed air system WSE include air receivers, pressure vessels, safety valves, pressure relief devices, pressure gauges and interconnecting pipework above the threshold. The scheme must be reviewed whenever a significant change is made to the system.

How we support the process

Our engineers have detailed knowledge of compressed air, nitrogen and process water chiller systems and understand how they are configured, how they are operated and where the pressure-bearing items are likely to be found. This means we can support the WSE process practically:

• Providing accurate system documentation and P&ID drawings to define the system boundaries
• Coordinating site access and preparing the system for examination
• Ensuring maintenance records are in order and available for the competent person
• Managing the examination schedule and keeping track of examination due dates
• Carrying out repairs or modifications identified during examination before re-examination takes place

For customers on a service contract with ALS, coordination of the WSE examination programme can be incorporated into the existing service relationship, so that nothing falls through the gap between service visits and statutory examination dates.

The legal position

Operating a qualifying pressure system without a valid Written Scheme of Examination is a breach of PSSR 2000 and a criminal offence under the Health and Safety at Work Act 1974. The HSE can issue prohibition notices, improvement notices and prosecute duty holders. There is no minimum fine. Insurance cover may also be affected if a system cannot demonstrate compliance.

The duty to have a WSE in place falls on the owner or user of the pressure system. PSSR 2000 should be read alongside PUWER 1998 (Provision and Use of Work Equipment Regulations), which places separate duties on employers to ensure work equipment, including compressors, is maintained in a safe condition and that adequate information and instructions are available. It is not the responsibility of the manufacturer, installer or maintenance contractor. All of these are relevant sources of information that feed into an accurate scheme.

How can we help?

If your system does not have a Written Scheme of Examination, or if your existing scheme has not been reviewed since the system was last modified, speak to us. We can assess what is required, coordinate the necessary documentation, and ensure the examination programme is practical and maintained going forward.

Call us on 01789 867640 or email enquiries@alsindustrial.co.uk. We respond to all enquiries the same working day.