Temporary Repair Failure

[ben]

Copying from an incident reported in 2012;

What Happened:
Ice formation was reported on the 3rd stage relief line on the associated gas compressor. A
pinhole leak was found and a wrap temporary repair was effected, following Technical
Authroity approval. The wrap was applied by a specialist vendor.
Approximately 9 days later a smell of gas (confirmed using ‘snoop’) was picked up at the wrap
repair. Bubbling & discolouration of the wrap was also noticed suggesting the wrap had
failed.

Lesson Learnt:
The cause of the wrap failure was initially thought to be insufficient curing time of the resin,
however following further analysis it was established that the surface temperature of the
pipework during application of the wrap was too low leading to a lack of adhesion between the
wrap material/resin and the pipework. It was also considered that inadequate pressure being
applied during the wrap application contributed to the premature failure of the repair which
was identified as a contributory factor.
The lesson learnt is to always ensure the pipe having the wrap applied is brought up to the
correct temperature, as per manufacturers guidance prior to application of the wrap.

Attached is the full form for reference.
For sharing & discussion purposes.

349860088-Incident-Alert-Wrap-Failure.pdf

[neo]

There are instance where temporary repairs have failed and the major reason include:
1. Engineering standards non-compliance
2. Lapse inspection /maintenance
3. Installation practices
I recall a case where a box-up repair was carried out by an external contractor which upon no proper sealing injection started leaking within 2 years time.

Thanks for sharing this.

[irish]

BP Grangemouth Refinery reported a failure from a temporary repair actually happened due to lack of attention towards converting a temporary repair to a permanent solution.

[octane]

Temporary repairs are required to be managed very well.
Internal thinning, damage mechanism is active all throughout and with no finite time of converting that to a permanent one would actual pose a risk.
Corrosion rates, associated piping inspection, localized monitoring, there are quite a lot of factors affecting the useful life of any temporary repair.

[irish]

Dependency on external support to engineer & manage the temporary repairs is required to be reinforced with engineering review & procedural /auditable management performed by on-site team.
Over and above this, a periodic review, inspection is needed which is to be defined, and reported. Based upon this, changes could be required to be made to existing repairs.

[novice123]

Thanks for sharing.

[ben]

The thing is that we still applyvwraps every now and then when needed, that too on hydrocarbon lines. Temperature of the line contributes a lot to the installation of the wrap and then the applied pressure during installation.
I understand that any wrapping done to arrest a leak temporarily must be applied with a method statement in place and not only that, ther should be a documented and signed inspection plan to follow all the critical activities during the installation.