Scotia Gas Networks and Sylmasta devise a pipe protection programme for underwater gas pipelines buried beneath rivers and streams across Scotland as more pipes become exposed to damage by climate change driving an increase in riverbed scour.

Case Study Overview

Site River network
Location Scotland
Pipe Type Underwater gas pipelines
Repair Type Pipe repair and reinforcement
Products SylWrap HD Pipe Repair Bandage

Pipe Defect

Large sections of the gas pipe network in Scotland run through river and stream beds. Whilst well buried during installation, changing conditions in waterways can lead to these pipes being exposed by riverbed scour and erosion.

Riverbed scour occurs when gravel, sand and rocks are washed away by fast-flowing water. The problem is intensified during floods, where rising water levels increase the speed of rivers and streams.

With climate change making extreme weather events more frequent, Scottish gas distributor Scotia Gas Networks (SGN) have seen a sharp rise in the number of their riverbed pipes becoming exposed by scour.

This poses a serious challenge to the gas network as without the covering of the riverbed, pipes are left at risk of being weakened and breached by prolonged impact damage from other debris carried by the water.

The problem of exposed pipes is not going to go away. Winter rainfall levels in Scotland increased by 19 percent in a decade between 2010-19 compared with a 30-year period from 1961 to 1990.

Knowing that even more of their gas network will become exposed by riverbed scour in future years, SGN contacted Sylmasta looking for a protection method effective on any submerged pipe regardless of diameter or material in any river across Scotland.

SylWrap Solution

Sylmasta put forward SylWrap HD Pipe Repair Bandage. SylWrap HD is a composite wrap with a water-activated resin which is easy to wrap and mould around pipework, even in underwater conditions. It sets rock hard in minutes to form an impact resistant, protective shield.

Before application on the gas network, SylWrap HD required several approvals from industry bodies. This was handled by SGN, with the process fast tracked through the system because of the importance of the project.

Although SylWrap HD already holds WRAS approval, it also had to be passed as safe to use in natural waterways by the Scottish Environment Protection Agency (SEPA).

Once testing had been completed, Sylmasta flew to Scotland to assist SGN with initial trial repairs in a shallow river around one-metre deep.

SGN contractors entered the water and wrapped SYL616 Bandages in a six layer repair along entire lengths of multiple exposed pipes.

As soon as SylWrap HD was submerged, the resin began working. The contractors worked quickly to ensure application was completed before SylWrap HD cured, leaving each wrapped pipe with a rock hard, 6mm thick shell protecting against future impact damage.

Outcome

Several different exposed pipes were protected with SylWrap HD during the trial, including one in an area where visibility was made difficult because of reeds from a bank.

At one point after repair, a number of intrigued fish even began swimming around a newly wrapped pipe to see what was going on. The testing carried out by SEPA and WRAS approval guaranteed SylWrap HD posed no danger to those fish or any other wildlife in the river.

Follow Up

One SGN contactor described working with SylWrap HD during the trial as “an absolute dream” because of how easy and quick it was to apply by hand whilst in the river.

The trial showed SGN they could protect hundreds of kilometres of pipework at a rapid rate using SylWrap HD.

They subsequently ordered over 500 SYL633HD Bandages for the pipe protection programme to start immediately, helping to maintain the integrity of the Scottish gas network for years to come.

Products Used

SylWrap HD Bandage
Water-activated wrap creates a rock hard, impact resistant shield around pipework

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