Making Sense of PSSR Defect Classifications

Regulation 10: the imminent danger finding

Regulation 10 is the regime's emergency brake. Where the competent person forms the opinion that the system will give rise to imminent danger unless repairs or modifications are carried out, or unless suitable changes to the operating conditions are made, they must make a written report to that effect at once, and the system must not be operated until those specified repairs, modifications or changes are made. The examiner also sends the report to the enforcing authority within 14 days of the examination.

What earns the finding is a condition where continued operation at the current limits relies on hope: pressure envelope below its calculated minimum thickness, cracking in a stressed zone, a safety valve or protective device that demonstrably will not act, evidence of overheating on a fired vessel, a repair done to no recognisable standard on a pressure part. The common thread is that the stored energy is no longer reliably contained or reliably relieved.

Read a Regulation 10 report with a lawyer's eye for its list, because the list is the lock and the key. The prohibition holds until the repairs, modifications or changes specified in the report are made: not until the system feels better, not until a different repair is done, and not until a fresh opinion is casually assumed. If the report specifies repair and re examination, both happen before pressure. If it permits operation at reduced limits pending work, those reduced limits are the law of the system in the meantime.

One route is closed on principle: postponement. Regulation 9(7) defers an examination that has not yet happened; it has no power over one that has already found imminent danger, and any suggestion otherwise misreads both provisions.

Repairs by a date: the Regulation 9(5)(b) entry and its two locked gates

The dated repair is the workhorse finding of pressure examinations, and Regulation 9(6) gives it teeth most duty holders have never read. The system must not be operated after the specified date unless the repairs or modifications have been completed, and, in the same breath, unless the changes to the established safe operating limits specified in the report have been made. Two gates, one date, both locked.

The second gate is the one estates miss. Where a report couples a repair with a limits change, doing the repair while quietly keeping the old limits does not clear the entry: the report's opinion was formed on both together, and 9(6)(a) is explicit that both must be done. Read every dated entry twice, once for the metalwork and once for the numbers, and make whoever holds the operating instructions change them the same week as the fitters attend.

Run the date itself with the same discipline as any statutory boundary. Plan the work inside it with margin for parts and access; pressure repairs routinely need coded welders, gaskets to specification and isolation windows that production must grant. Keep the evidence the competent person will want at the next examination: procedures, materials, test records. And where the date is going to be missed, act before it passes: the lawful positions are the work done, the system stopped, or a fresh examination and opinion, and silence is not on the list. A system running past a 9(5)(b) date is not late paperwork; it is operation the report's own words prohibit.

Deratings: when the finding changes what the system is

Some findings do their work not with a spanner but with arithmetic. A derating, a change to the established safe operating limits, is the competent person concluding that the system as found can be safe, but only at less than it used to do: lower pressure, lower temperature, a reduced firing rate, a smaller allowable cycle count. From the moment the report specifies it, the system's legal identity has changed, and the old figures on the gauge become history rather than headroom.

Deratings arrive in two tempers. The temporary derating bridges to a repair: run at 7 bar until the shell course is repaired, then the limits may be restored on re examination. The enduring derating recognises consumed life: wall thickness that will never grow back, a vessel ageing out of its original duty, and the limits step down as the margin does. Both are equally binding; they differ only in whether a repair can reverse them.

The hard part of a derating is not accepting it but propagating it. The number must reach the safety valve settings where relevant, the operating instructions, the control setpoints, the interlocks, the marking at the plant, and the people who run it on nights as well as days. An estate that files the report and leaves the compressor cut out at the old pressure has not derated anything; it has documented the limit it is exceeding. Walk the number to every place the old one lived, and record that walk, because proving the propagation is exactly what an inspector asks for after any event.

Treat a derating also as information about trajectory. Limits that step down are a system spending its capital, and the trend line across reports tells you the retirement date long before anyone says the word replacement.

The scheme suitability comment: the finding that rewrites the regime

Regulation 9(5)(d) hides the most strategic sentence on the report. The competent person must state whether the scheme of examination remains suitable for preventing danger from the parts it covers, or should be modified, with reasons. It reads like housekeeping and is anything but: it is the examiner telling you whether the entire examination regime still fits the plant in front of them.

Scheme comments arrive for real reasons. The plant changed: a new receiver, rerouted pipework, a different duty, hours doubled. The knowledge changed: corrosion found where the scheme never looked, a failure mode the intervals do not respect, readings that say the interval is too generous or unnecessarily tight. Or the paperwork drifted: components on the plant missing from the scheme, or scheme items long since removed. Each is the same message: the map no longer matches the territory.

Act on the comment as a project with an owner, because it will not action itself. The scheme is revised by or certified by a competent person, the revision reaches whoever holds the scheme with the plant, and the next examination runs against the new scheme. Leave the comment unactioned and the consequences compound quietly: examinations that legally satisfy a scheme while missing the plant's actual risks, and a paper trail showing the competent person told you the scheme was unsuitable in writing, annually, while nothing changed. Beside any later incident, that trail reads as badly as anything in this regime can.

There is also money in the comment's other direction. Where the examiner records that intervals could safely extend or scope could rationalise, the scheme revision buys cheaper compliance for years, and duty holders who never read 9(5)(d) never collect it.

Observations and the series: findings that only exist across years

The quietest entries on a pressure report, the noted conditions, the thickness readings, the comments that ask nothing, are individually weightless and collectively the most valuable engineering data the estate owns. Pressure plant fails on rates, corrosion per year, cycles consumed, drift in relief settings, and rates are invisible on any single report. They exist only in the series.

Keep the series deliberately. Thickness readings tabulated per location per year, not buried in successive PDFs; relief valve test results with dates; every observation logged against the vessel with its measurement where one exists. Three data points make a slope, and a slope makes a forecast: the year the bottom course meets minimum wall, the examination at which the interval will need shortening, the budget cycle in which the replacement lands. Estates with series buy vessels in planned procurement; estates without them buy vessels by emergency courier.

Feed the series back into the regime. A corrosion rate that halves after a drain repair proves the fix worked; one that does not proves it did not, in numbers nobody can argue with. Rates justify scheme interval decisions in both directions, and a competent person shown a well kept series will write sharper, earlier, more useful comments, because the estate has demonstrated it reads them.

Protect the series through change. When a vessel is replaced, keep its history until the successor has a trend of its own, because the old rate is the design brief for the new duty. When providers change, the series is yours, not theirs: reports belong to the duty holder, and continuity of data is a thing to demand at handover, in writing, before the last visit under the old contract.

Turning a report's findings into the next twelve months

A pressure report is spent the day it is filed and invested the day it is translated, and the translation is a one hour discipline after every examination round. Take each finding and give it a home in a live system: the Regulation 10 and dated entries into the maintenance plan with owners and margined dates, limit changes into instructions, setpoints and training, scheme comments into a revision task with a name on it, and every measurement into the series.

Then read the round as a whole, because findings cluster and clusters are the real intelligence. Three receivers with corrosion at the drain end is a condensate management problem wearing three disguises. Repeat relief valve findings are a testing regime problem. A scatter of small entries on one contractor's installations is a workmanship problem that procurement should hear about. Individual findings get repairs; clusters get root causes, and the estates that distinguish them spend less on both.

Finish by resetting the calendar deliberately. Next examination dates from 9(5)(c) into the diary as absolute boundaries, decision points set weeks ahead of every dated repair, the postponement rules noted for any examination that production will struggle to release, one postponement per examination, competent person's written agreement, user's written notice to the enforcing authority before the due date, and never as a tool for findings already made. A pressure regime run this way is boring, and boring is the entire ambition: stored energy, of all the hazards on an estate, is the one that should never be interesting.