Leaking coupling joints on a 650mm ductile iron pipe located in an inspection pit are sealed using SylWrap Pipe Repair products
Two leaking coupling joints on a 650mm ductile iron pipe undergo repair

Inspection Pit 650mm Ductile Iron Pipe Leaking Coupling Joints Repair

A water company repair two faulty coupling joints connecting a two metre section of 650mm ductile iron pipe to a mains water line after they were discovered to be leaking within a disused inspection pit which had been filled with earth.

Case Study Overview

Site Pipe inspection pit
Location UK
Pipe Type 650mm ductile iron
Repair Type Live leak pipe repair
Products Wrap & Seal Pipe Burst Tape, SylWrap HD Pipe Repair Bandage

A 650mm ductile iron pipe undergoes repair to fix leaking coupling joints in a pipe pit in the UK

Pipe Defect

Originally, the pit had been an inspection chamber housing a valve. Many years ago, the valve was replaced with a two metre section of straight ductile iron pipe connected to the existing line carrying mains water via two coupling joints.

Once the valve had been removed, the pit had been filled with soil and forgotten about. It was rediscovered by a water company during maintenance work. The soil within the pit was extremely muddy, suggesting a leak.

After excavation, the section of pipe running through the pit was found to be in poor condition and leaking from both couplings.

The water company now needed a repair method to seal the couplings flexible enough of being effective within the confines of the pit.

Each coupling was 80mm wide but rose 100mm off the pipe, creating an awkward ridge which needed to be sealed. There was only 35mm clearance between the couplings and the floor of the pit.

A section of ductile iron pipe leaking from two coupling joints in a pipe pit prior to undergoing a live leak repair
The pipe was discovered to be in poor condition after excavation of the pit
The couplings were raised 100mm above the pipe, leaving an awkward shaped ridge to seal

SylWrap Solution

A polythene sheet was squeezed under the pipe to prevent mud and dirt being picked up during the application of Wrap & Seal Pipe Burst Tape used to seal the couplings.

Wrap & Seal is made from self-amalgamating silicone which stretches by 300 percent and fuses to form a solid rubber band for live leak repairs.

Multiple Wrap & Seals will also fuse to each other, which is how in this application a repair was built over and around the couplings to seal the leaks despite the difficult ridge.

The two couplings and the areas surrounding them were then encompassed with SylWrap HD Pipe Repair Bandage.

SylWrap HD is a composite wrap with a water activated resin. It sets rock hard in minutes to provide an impact resistant layer of protection to repairs and pipework.

SYL1266HD Bandages were used on both couplings. At 300mm wide, these wraps provided more than enough coverage to mould around the couplings.

With both ends of the pipe wrapped with SylWrap, the water company could refill the inspection pit with soil safe in the knowledge that it had been suitably fortified to prevent further deterioration.

Completed repair of leaking coupling joints on a 650mm pipe in a pit
A 650mm pipe leaking from two coupling joints undergoes repair despite being confined to a pit
Completed repair with SylWrap encompassing both couplings prior to reburial


The water company were happy to have found a repair versatile enough to work around both the ridge and the space constraints which meant a pipe clamp would not have been effective.

Within an hour, the two coupling joints on the pipe had undergone a successful, WRAS approved repair. Using materials with WRAS approval was a legal requirement because the pipe carried mains water.

Follow Up

For future repairs to pipework sections in confined spaces including inspection pits, the water company now knows how straightforward they can be to repair using a SylWrap pipe repair products.

Products Used

Wrap & Seal Pipe Burst Tape
Self-amalgamating silicone repair tape which fuses to build a high pressure repair

SylWrap HD Bandage
Water-activated wrap sets rock hard to reinforce repairs and fortify pipelines

Pipe Repair Contractor Case
Easy-to-store case with enough products to make up to six emergency pipe repairs

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