Nature of defect
The 48” Cooling Water line had suffered from external and internal corrosion. This resulted in a large through-wall defect at the 12 o clock position. Adjacent to the leak was a second corroded section approximately 500mm away. After surface preparation was complete, the second location also produced a leak. The client required a composite repair to seal the leak locations and to bring the line back up to its full design specification.
There was a 4-metre section adjacent to the above section that also required a repair. Several areas within this section had suffered from external corrosion resulting in an expected RWT reading of 1mm.
Solution
Metalyte Pipeworks solution was to install a repair, initially using Herculyte epoxies and a pre formed steel plate to seal the defects with a minimum overwrap of 10 layers of Dragon-Q-UHT composite.
Repair method
The full repair area of 8 metres was prepped by on site shot blasters to Sa 2.5 with a minimum surface roughness of 55 microns. The Metalyte Pipeworks team then installed the cold bonded epoxy plates over the through wall defects. Any areas of wall loss were repaired using a high compression load transfer paste.
The cold bonded plates and load transfer paste was allowed to cure before the Dragon composite was applied. A total of 10 layers was applied over the 8 metre area to bring the line back up to full design specification. Once the composite was fully cured and tested, the Metalyte technicians applied 2 coats of UV resistant protection.
