Decommissioning evidence built forward, not reconstructed at the end.

The first task is a register that reflects the asset as it is, not as it was designed. Legacy P&IDs, marked-up as-builts, the maintenance system export and the isolation philosophy are parsed into a tag register, with conflicts between sources surfaced for engineer review rather than silently resolved.

Where a source disagrees — a valve on the drawing but not in the maintenance system, a line modified without the drawing being updated — the conflict is shown with both references so a walkdown can settle it before isolation begins, which is where discrepancies are cheapest to find.

The register then becomes the spine of the campaign: every isolation, drain, flush, cut and item removed is recorded against a tag the whole team agrees exists.

A clear-for-removal certificate cannot be issued while a drain record is missing, a sampling result is outstanding or a Category A finding is open against the system — the same gating logic as new build, applied to a hazard being retired rather than a plant being started.

Naturally occurring radioactive material, mercury, asbestos, residual chemicals and stored energy are recorded as their own findings against the tag where they were found, so the specialist scope that follows is planned from evidence rather than a verbal handover between shifts.

Isolations are held against tags with their point, method, owner and current state, so the live picture across a multi-year campaign is a query rather than a paper register kept by whichever shift was on at the time.

A removal campaign has the same constraints as an offshore construction campaign: bed space, vessel days, weather and a lift schedule that cannot be rearranged casually. What can be done onshore or before the vessel arrives should be, and what remains has to be sequenced against readiness that is actually proven.

Progress is reported by system state — isolated, flushed, hydrocarbon free, cleared, removed — rather than by percentage complete, because a lift plan needs to know which structures are ready to cut, not what the average is.

Records are captured on tablets at the tag, offline, by the crews doing the work, with photographs of the isolation and the condition found — the same field discipline as a commissioning campaign, which keeps the reporting burden inside the working day.

The close-out submission needs to show, per system, what was isolated, how it was made safe, what hazardous material was found and how it was managed, what was removed, where it went and who signed each step — all of it already in the register if it was captured there in the first place.

Materials and waste consignments are recorded against the tags they came from, so the traceability chain from a specific piece of equipment to its disposal or reuse route survives the campaign.

The export is generated per system and per campaign phase with signer name, role, organisation and timestamp on every record — turning a multi-year removal programme into a submission that can be defended rather than assembled.