Case Study: Live Leak Repair of a Cracked 4 bar 250mm PCCP Pipe Stub in Saudi Arabia

Case Study Data

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Site
Industrial Site
Location
Saudi Arabia
Repair Type
Live leak repair
Defect
Cracked 250mm PCCP stub with no isolation valve operating under 4 bar pressure

Products Used

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Wrap & Seal Pipe Burst Tape
Multiple self-fusing silicone repair tapes combined to build a high pressure seal over the leak areas

SylWrap HD Pipe Repair Bandage
Reinforced the initial repair with wrapping extended to protect the entire stub

SylWrap Pipe Repair Contractor Case
Contains multiple Wrap & Seals and SylWrap HD to carry out up to six live leak repairs

Case Study PDF

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Case Study Details

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The prestressed concrete cylinder pipe (PCCP) stub was connected to a main header operating under 4 bar pressure. Wear and tear had caused numerous cracks to appear in the stub, through which significant amounts of water was escaping and causing flooding.

Because there was no isolation valve, preventing flow to the stub from the main header was impossible. Shutting off the main pipe for carrying out either a repair or replacement was impractical and there was not enough room between the stub and the floor to fit a pipe repair clamp.

A live leak repair method was therefore needed. This proved extremely challenging and after several attempts which failed to make any reductions in the amount of water being lost, the engineers charged with fixing the stub turned to Sylmasta.

As this was a live leak, Wrap & Seal Pipe Burst Tape was used to seal the cracks on the stub. Wrap & Seal is made from self-amalgamating silicone and stretches by 300 percent to fuse into a solid rubber band around pipework.

Multiple Wrap & Seals were applied down a 200mm area of the stub. In the same way in which a single tape amalgamates to itself, these separate tapes fused together to create a repair with enough pressure resistance to seal the cracks.

Once the engineers were satisfied that the leaks had been suitably arrested, the stub was overwrapped with SylWrap HD Pipe Repair Bandages.

SylWrap HD is a composite repair wrap with a water activated resin which sets rock hard in minutes. It reinforced the repair by providing an impact resistant sleeve around the PCCP pipe stub

After this section of the stub had been sealed, it was decided to reinforce the underground section at the same time. Doing so would protect the remainder of the ageing pipe from future ruptures, which might prove difficult to identify if they were leaking below the floor.

The floor was dug up around the stub to reach the pipe. Once accessed, a further 200mm section of previously underground pipe was wrapped with SylWrap HD.

One final covering of SylWrap HD was then applied over the bandages already covering the two phases of the repair, encompassing the entire stub and providing reinforcement before the floor was relaid.