A prosecution or improvement notice under the Pressure Systems Safety Regulations 2000 (SI 2000/128, GB) shows something a guide on its own cannot: what an inspector actually looked for, and where reasoning that seemed sound at the time turned out not to hold up. The regulations place the legal duty on whoever operates the system, which in most workshops means the owner, so the pattern running through enforcement history is directly about decisions you make yourself.

Where the duty actually sits

Under regulation 8 of the Pressure Systems Safety Regulations 2000, the user of an installed system (the person operating it day to day, not necessarily the person who bought it) must have it examined in accordance with a written scheme of examination (the documented inspection programme required for systems above the bar-litre threshold) at the intervals that scheme sets. That duty does not move to a fitter, a distributor or a previous owner just because one of them was involved in the system at some point.

Reading how these duties get tested in practice is not a substitute for a competent person's assessment of your own system (someone with sufficient knowledge and experience to examine a pressure system safely, as the regulations define the term). It is a way of seeing which questions that assessment is actually built to answer, before your own system is the one being assessed.

Why the pattern matters more than any single outcome

A case rarely turns on anything exotic. It turns on a written scheme that lapsed, an examination that was booked late, or a receiver nobody had checked against the bar-litre threshold since the day it went in. Reading several cases together shows which of those failures keep recurring, and that tells a workshop owner more than any single outcome read on its own.

Notices and prosecutions involving pressure systems appear as they are reported in the news for compressed air users, alongside what each one means for an operator. The terms used in this area, including written scheme and competent person, are set out in the compressed air glossary if you want the short definition before reading further.

When HSE prosecutes over a pressure system or issues a notice, the resulting report follows a similar pattern. It sets out what happened to the vessel or pipework, which duty under the Pressure Systems Safety Regulations 2000 was found wanting, and what enforcement followed. Read as a group, these reports point to a small number of recurring failures.

The duty that usually turns out to be missing

Most cases turn on one of two duties. The first is regulation 8, which requires the user of an installed system to have it examined in accordance with a written scheme of examination at the intervals that scheme sets. The second is the existence of the written scheme itself, drawn up under regulation 8 by a competent person before the system is first used. A system can be perfectly sound and still fall foul of either duty on paper, and a system can also fail physically in a way the paperwork never flagged because the scheme's intervals were too wide for the corrosion or wear actually taking place.

What follows a failure

Enforcement runs from an improvement notice, giving a set period to put a specific defect right, through to prohibition of use where HSE judges the risk immediate, up to prosecution under the Health and Safety at Work etc. Act 1974 where the failure has caused or could have caused serious injury. Which route is taken depends on what was found and how far short of the regulation it fell.

What a case report does not do

A published case describes one system, examined after something had already gone wrong or been missed. It is not a checklist you can run against your own receiver and pipework, and reading it is no substitute for having your own system assessed by a competent person against your own written scheme. What it gives you is a working picture of where the duty is most often found to be missing in practice, which is a different and more useful thing than a list of what the regulations say in the abstract.

HSE's own notices and prosecution reports as they are published sit in the news for compressed air users, and the terms used above, including written scheme of examination and competent person, are defined in the compressed air glossary.

Across the pattern of pressure systems enforcement, the same handful of duties keep turning up. A receiver crosses the 250 bar-litre threshold in regulation 2(1) of the Pressure Systems Safety Regulations 2000 (SI 2000/128, GB) and nobody worked that out. A written scheme of examination exists but the interval it sets has been allowed to slip. The person who signed off the last examination was never a competent person within the meaning the regulations give that term. The regulations put the duty on whoever has control of the system, and a subcontracted service visit does not move that duty onto someone else.

Where the failure usually sits

• No written scheme was drawn up for a receiver that, once measured, does in fact exceed 250 bar-litres.
• A written scheme exists, but the examination it calls for was not carried out within the interval the scheme itself sets.
• The examination was carried out by someone without the standing to be a competent person under the regulations.
• A safety device, most often the pressure relief valve, was not maintained to the maker's own instructions.
• No record of any examination survives, so nobody can show what was checked or when.

What to check on your own system now

Work out the bar-litre product of each receiver you run: capacity in litres multiplied by its maximum allowable pressure in bar. For anything above 250 bar-litres, find out whether a current written scheme exists, who drew it up, and when the next examination under it falls due. Then ask who carried out the last one and on what basis they count as a competent person, because a written scheme sitting in a drawer with no examiner behind it proves nothing on its own.