Pressure systems and the written scheme of examination (PSSR)

Pressure systems get talked about less than lifting equipment or electrical testing, mostly because fewer buildings have them in a form that's obviously visible — but where relevant plant does exist, boilers, compressed air systems, certain refrigeration plant, the obligations under the Pressure Systems Safety Regulations are genuinely demanding, and the written scheme requirement in particular trips teams up who haven't dealt with it before.

What a written scheme of examination actually is

Where a pressure system meets the relevant threshold, it needs a written scheme of examination — a document, prepared by a competent person, setting out which parts of the system need examining, at what intervals, and what the examination should check for. This isn't a generic certificate; it's specific to the actual system installed, which means a scheme written for one boiler installation doesn't automatically transfer to a different one, even a similar one, without review.

Examination vs day-to-day operation

The written scheme sits alongside, not instead of, safe day-to-day operation of the system — safety valves, gauges and controls still need routine attention as part of normal maintenance. The examination under the written scheme is a periodic, more formal check by a competent person, distinct from the operational checks that happen far more frequently. Confusing the two, the same trap that shows up with LOLER thorough examination, is a common source of gaps.

• –Identify which pressure systems on site actually meet the threshold requiring a written scheme
• –Get the scheme prepared or reviewed by a genuinely competent person, specific to the installed system
• –Track examination dates set by the scheme separately from routine operational maintenance visits
• –Keep the scheme itself under review — a system change should trigger a scheme review, not just continue on autopilot

Where this connects back to the wider asset picture

As with lifting equipment, the starting point is knowing which assets on the register actually carry a PSSR obligation — pressure systems are exactly the kind of category that gets missed on a multi-building estate if nobody's deliberately flagged them, since they're often less visually obvious than a lift or a distribution board. Once flagged, the written scheme's own intervals should drive the schedule directly, rather than being folded into a generic PPM interval that wasn't designed with the regulation in mind.

Findings from an examination under the scheme need the same follow-through as any other statutory finding — see what happens when an inspection turns up a defect for how that should be handled.

The scheme that nobody has read since it was written

A written scheme of examination is specific to the system it was drawn up for, and systems change. A vessel replaced, a safety device swapped for a different type, a pipework alteration during a refurbishment — each can put the physical system out of step with the document that governs how it gets examined. The scheme does not object; it simply continues describing a system that no longer exists in that form.

Which makes any modification to a pressure system the trigger for revisiting the scheme, not just for updating the asset register. A scheme that has not been reviewed since installation, on a system that has been altered since, is the quiet version of this failure.

Common mistakes

• –Not revisiting the written scheme after the system is modified
• –Treating the scheme as a filing requirement rather than an operating document
• –Confusing routine operation and maintenance with examination under the scheme
• –No record of which competent person drew the scheme up, or when
• –Assuming a new system is covered by an existing scheme
• –Holding the scheme centrally where the people operating the system cannot see it

The scope and content of a written scheme should be set by a competent person under the current Pressure Systems Safety Regulations and HSE guidance — this post gives the shape of the obligation, not a substitute for that assessment.