A 350mm effluent steel pipe running under salt marshes undergoes repair after being found to be leaking from both ends of a clamp

Chemical Plant Repair 350mm Steel Effluent Pipe Running Under Salt Marshes

A chemical plant in the United Kingdom had to access, excavate and repair a leaking 350mm effluent pipe running underneath salt marshes and out to sea in an eight hour window whilst the tide was out.

Case Study Overview

Site Chemical plant
Location United Kingdom
Pipe Type 350mm steel effluent pipe
Repair Type Leak repair
Products Sylmasta AB Original Epoxy Putty, SylWrap Pipe Repair Bandage

Repair of a leaking 350mm steel pipe running underneath salt marshes and out to sea from a chemical plant

Pipe Defect

The pipe carried effluent from the chemical plant underneath salt marshes and out to sea. It had undergone repair just one year earlier, where the original cement coating was cut away and a clamp fitted. When this was discovered to have failed, a new approach was needed.

A specialist marine engineering contractor were appointed by the chemical plant. They excavated the problem section and carried out an initial inspection of the pipe, which revealed it to be leaking from both ends of the clamp.

To complicate matters further, the steel had significantly deteriorated where the cement had been taken away. The wall of the pipe was now so thin beneath the clamp that there was a significant risk of the line collapsing if the original repair was removed.

Contractors could only access the pipe whilst the tide was out and with no heavy equipment, as it would simply sink
Water and sludge was pumped away to access the pipe
A leaking effluent steel pipe requiring repair under salt marshes
Excavation revealed the pipe to be leaking from both ends of a clamp fitted during a previous repair

SylWrap Solution

Accessing the pipe was only possible whilst the tide was out. That left just an eight hour timeframe to excavate and repair before the tide returned and the pipe was lost again. No heavy tools or machinery could be used as they would sink when transported over the salt marshes.

As soon as the tide went out, the contractors returned to the salt marshes and excavation began. A wooden frame was built to create a safe working area and sludge and water pumped away. The pipe and the repair clamp were then cleaned.

It was decided to leave the clamp in place and encapsulate it with Sylmasta AB Original Epoxy Putty. AB Original is a super-strength, waterproof epoxy putty with high resistance to corrosion and chemical attack.

It was mixed by hand and pushed onto the clamp, permanently sealing all the holes through which effluent had previously escaped.

A concrete coating was applied over the entire excavated section, followed by several layers of SylWrap Pipe Repair Bandage.

Numerous Bandages were smoothed and wrapped around the pipe, curing within five minutes to form a reinforced protective sleeve. This restored the integrity of the line, uniting and strengthening the weak and solid areas of the repair.


The speed and ease with which both AB Original and SylWrap Bandage were applied and effective enabled the repair to be completed in the eight-hour window. By the time the tide returned, the pipe had been successfully sealed ahead of being covered with mud and seawater again.

Follow Up

There were two happy parties following the completion of the repair. The chemical plant no longer had a leaking effluent pipe. The contractors were suitably impressed with the products and technical advice provided to use AB Original on a similarly complex application for a different client.

Products Used

Sylmasta AB Original
Super-strength, waterproof epoxy putty with excellent resistance to corrosion

SylWrap Pipe Repair Bandage
Water-activated wrap sets rock hard to reinforce, protect and strengthen pipework

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