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Written Scheme of Examination

By law you need to have an up-to-date Written Scheme of Examination for your compressed air system

All new and existing compressed air installations must conform to the Pressure Systems Safety Regulations (PSSR2000). All pressure systems larger than 250 bar/litres must have a ‘written scheme of examination’ and a statutory inspection in accordance with the written scheme.

A written scheme of examination is a report that details safety devices and components associated with the systems pressure vessels. It also includes inspection periods for each device or component. In some cases a schematic drawing of the whole air network is required.

Airpower UK are able to provide all necessary services required by the pressure systems safety Regulation

Click here to see the HSE PSSR 2000 document



Getting a Written Scheme of Examination is relatively straightforward. Once you have identified a qualified person to write and carry out the WSE, it is simply a case of the qualified person attending site to identify, inspect and test all the safety related equipment in your compressed air system.

Normally the identification stage can be completed when the system is live. Normally the inspection / test can only be carried out when the system is drained and not operating.

Speak to Airpower UK and we can get one of our qualified inspectors to come to site to discuss the process further with you.



There are multiple steps in completing a WSE. These steps are outlined below, but the detailed steps will vary with the scale, complexity and size of the complete compressed air system.

Record all safety devices – The first step is to record all the safety devices in your current compressed air system. This can be done as a sketch or as written list or table. Items included in the WSE are pressure vessels, safety valves, ball valves, pressure gauges and numerous other items.

Record serial numbers and tag items  – The serial number (if present) for each item will be recorded and each item will be tagged for easy identification in the future.

Write the WSE document – The next step is to put together the WSE document. This lists each item mentioned above and often includes a schematic layout of your system, listing all the tagged items and their location relative to each other. The WSE document will also include re-inspection periods for each type of product and potentially other certification and test processes.

Complete the operation test / safety inspection – The final stage is completing an operation test / safety inspection for all the safety related items listed above. Once all this has been completed and everything has passed the test the WSE is complete.

The order in which the items above are completed will vary with the scale, complexity and size of the complete compressed air system.

Once the WSE is completed it is valid until the next re-inspection cycle

If the compressed air system changes, eg you add another receiver or another pipework branch, the WSE needs to be updated with the changes made and the new safety related items need to be recorded tagged and checked to fall in line with the other equipment.


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