For many vessels, exchangers and heaters, a shutdown is the only chance in years to look inside. What inspectors find determines how much repair work is done, and the quality of those repairs determines whether the equipment runs safely until the next stop. Inspection and quality controls during shutdown maintenance are therefore central to the whole turnaround, not a side activity. The sections below cover how inspection is planned, how findings turn into repairs, and the quality checks that apply before equipment is closed, for inspection engineers, maintenance managers and quality leads.
How does shutdown inspection differ from construction QC?
Construction QC checks that new work is built to specification. Shutdown inspection assesses the condition of equipment that has been in service, looking for corrosion, erosion, cracking and other damage, and then checks the quality of any repairs. Both need qualified people and good records, but the questions they answer are different.
Building the inspection plan
The shutdown inspection plan usually draws on:
- Statutory and regulatory inspection requirements
- Risk-based inspection (RBI) assessments
- Findings and recommendations from previous inspections
- Process changes and operating upsets since the last shutdown
- Known damage mechanisms for each equipment type and service
The plan defines what will be inspected, by which method, to what extent, and who will do it. It feeds directly into shutdown scope development.
Typical inspections by equipment type
| Equipment | Typical inspection activities |
|---|---|
| Pressure vessels and columns | Internal visual inspection, ultrasonic thickness testing, crack detection by magnetic particle or penetrant testing |
| Heat exchangers | Tube testing by eddy current, IRIS or remote field methods; tubesheet and shell inspection |
| Piping | Thickness measurement, inspection for corrosion under insulation, radiography where needed |
| Fired heaters | Tube thickness and diameter checks, visual inspection of tubes, supports and refractory |
| Relief valves | Removal, bench testing, inspection and resetting |
| Storage tanks, where in scope | Floor scanning, shell thickness, roof and seal inspection |
Exchanger inspection is described in more detail in heat exchanger maintenance during turnarounds.
From findings to repairs
- Record the finding with location, extent and photographs.
- Assess it. Engineering decides whether the equipment is fit for continued service, needs repair or needs replacement. Fitness-for-service methods, such as those in API 579-1/ASME FFS-1, may be used.
- Define the repair and the procedure, including materials and welding requirements.
- Approve the repair through the agreed authority, recording any effect on the schedule.
- Execute and inspect the repair to the same standard as new work.
Speed matters. Findings that wait days for an engineering decision hold crews and push jobs toward the critical path. Agree before the shutdown who can approve repairs on each shift, and make engineering support available at night for critical equipment.
Quality controls on shutdown repairs
- Welding: qualified procedures and welders, with inspection before, during and after welding, as described in welding inspection from fit-up to final acceptance
- Heat treatment and hardness testing where the material or service requires it
- Material verification: positive material identification for alloy replacements
- Pressure or leak testing after repairs, as required
- Bolted joints: correct gaskets and bolts, controlled tightening and joint tagging
Final inspection before box-up
Before a vessel or exchanger is closed, an inspector should confirm that internals are correctly installed, repairs are complete and accepted, and no tools, rags or debris remain inside. Foreign material left in equipment is a familiar cause of startup problems.
Records and updates
Inspection reports, repair records and test results should be completed during the shutdown and used afterward to update the inspection database and RBI assessments. Close-out of the documentation is part of closing out shutdown work packages.
Qualified people
Shutdown inspection needs inspectors qualified for in-service work, often holding certifications such as API 510, API 570 or API 653, alongside qualified NDT technicians. Staffing these roles is covered in QA/QC and HSE staffing for construction and maintenance. Apex Core Engineering supplies inspection and QA/QC personnel for shutdowns, working within the management systems listed on its certifications page.
Frequently asked questions
What is risk-based inspection?
An approach that sets inspection priorities, methods and intervals based on the likelihood and consequence of equipment failure.
Who decides whether damaged equipment can stay in service?
Engineering, usually inspection and integrity engineers, based on the findings and, where needed, a fitness-for-service assessment.
Why is a final inspection before box-up important?
It confirms repairs and internals are complete and that no tools or debris remain inside, which prevents startup problems.
Discuss shutdown inspection support with Apex Core Engineering.