In a refinery, a petrochemical plant or a power station, the planned shutdown (turnaround, TAR) is the event that defines the operating year: the installation stops completely for a planned window — typically two to six weeks — to concentrate all the maintenance that cannot be done with the plant running: opening and inspecting equipment, replacing piping, boiler repairs, project modifications and the statutory tests. It is the opposite of a breakdown: everything is decided months in advance. And precisely for that reason, missing the window has no technical excuse — it almost always has a planning cause.
Why every day costs so much
While the shutdown lasts, the plant does not produce. In a mid-sized refinery, the lost margin can comfortably exceed a million euros a day; in a chemical plant the order of magnitude is comparable. That produces a merciless arithmetic: the cost of one extra day of shutdown frequently exceeds the cost of the entire welding workforce of the event. Saving on the crew only to slip a week is the worst financial trade a maintenance manager can make. The figures vary by site and by market, but the direction never does: the shutdown line in the budget is dwarfed by the production it exists to protect.
The four phases of a turnaround
1. Scope (T-18 to T-12 months)
The worklist is defined: mandatory inspections, recommendations from previous shutdowns, improvement projects that ride the window. A scope still growing three months before the start is the first symptom of a turnaround that will slip. The key discipline here is the scope freeze: from an agreed date onwards, all new work goes onto a reserve list and only proceeds if it does not compromise the critical path.
2. Planning (T-12 to T-3 months)
The scope turns into work packages, sequences, cranes, scaffolding, work permits — and people: how many welders, pipefitters, boilermakers and supervisors, with which qualifications, on which shifts. This is where maintenance contracts are awarded and qualified labor is reserved.
3. Execution (T-0 to mechanical completion)
Weeks on two or three shifts, with inspection and non-destructive testing tracking joint production continuously. Daily management runs against the progress curve: every package that slips eats the float of the critical path.
4. Start-up (post-completion)
Pressure tests, valve reinstatement, pre-start-up safety checks and ramp-up. Lessons learned are documented now — they are the starting point for the next shutdown's scope.
The real bottleneck: qualified people
Steel, flanges and cranes are bought ahead of time and wait in a warehouse. A qualified 6G TIG welder with clean radiography waits in no warehouse. And the market plays against you: shutdowns cluster in the same spring and autumn windows, so Tarragona, Cartagena, Huelva and Puertollano compete for the same profiles in the same weeks. And the scarcity is not cyclical: the age pyramid of the trade means more qualified welders retire every year than enter it, and no shutdown window waits for the market to rebuild itself. Whoever starts looking for welders a month before the event chooses among the leftovers. How to size the crew in concrete terms — joints-per-day ratios, criticality, buffer — is covered in our guide to sizing the welding crew for a refinery shutdown.
The KPIs that define success
Measure them per shift, not per week: in a twenty-day window, one week of data is a quarter of the event.
- Window met — actual versus planned start-up date: the indicator that summarizes all the others.
- Repair rate — percentage of joints rejected under radiography or ultrasonics; above a few percent, rework starts eating the critical path.
- Safety — recordable accidents and incidents; a shutdown with hundreds of external workers on site at once is the risk peak of the year.
- Adherence to the progress curve — weekly deviation between actual and planned progress, per work package.
- Cost deviation — against the approved budget, separating added scope from inefficiency.
How to secure welders ahead of time
- T-6 months: reserve the critical crew (6G, alloys, scarce profiles) with a contractual commitment, not an emailed intention.
- T-3 months: full document validation — UNE-EN ISO 9606 qualifications with confirmations up to date, A1 forms, PRL, medical checks.
- T-1 month: plant access passes, lodging and logistics closed; entry weld tests if the client requires them.
- T-1 week: crew on the ground, safety induction done, first productive day from hour zero.
- During the event: a 15-20% buffer and a replacement plan with a guaranteed lead time — absences always happen.
The mistakes that burn the most windows
- An unfrozen scope — work entering at the last minute with no recalculation of resources or sequence.
- Late booking of critical personnel — the 6G welders are sought a month before the event, when they are already committed to another plant.
- Documentation validated on the fly — expired qualifications or incomplete A1 forms discovered at the gate.
- Improvised logistics — lodging ninety minutes from the plant that turns eight-hour shifts into twelve-hour days.
- No replacement plan — every absence is negotiated from scratch, with the shutdown clock running.
- Undersized inspection — joints get welded but not released, and real progress goes blind.
Iron Pulse supplies complete crews of homologated welders, pipefitters and mechanics for shutdowns across Spain, with the documentation dossier validated before arrival and fast replacement during the event. Talk to the team at the planning stage — that is where the window is won.
