Case Study: Heavily Corroded Pipe Repair Keeps a District Heating System Running

Winter warmer – Sylmasta keep a district heating system running after corrosion breached two sections of underground pipework

After heavy corrosion caused several breaches to sections of pipe in a district heating system, a local council in the United Kingdom required a repair method to avoid fitting replacement parts, a process which would have left residents without heating for days in the depths of winter.

Case Study Data

Domestic district heating system
Yorkshire, United Kingdom
Repair Type
Leak repair
Breaches caused by heavy corrosion

Products Used

Wrap & Seal Pipe Burst Tape
Flexible waterproof repair tape sealed the breaches on even the most inaccessible sections of pipe

SylWrap HD Pipe Repair Bandage
Applied over the Wrap & Seal for an impact resistant layer of protection to the repairs and pipework

SylWrap Universal Pipe Repair Kit
Wrap & Seal and SylWrap HD were supplied in the Universal Pipe Repair Kit

SylWrap Pipe Repair Contractor Case
For future emergencies, a Contractor Case provides enough equipment for up to six live leak repairs to pipes of all types and diameters

Case Study PDF

Case Study Review

District heating is the provision of hot water for heating from a central source to several houses or flats, often managed by district councils. 

The hot water is usually derived from a conventional boiler, although it may also come from a variety of sources including solar power, an incineration plant or an on-site power station.

A network of pipes runs underground both to and from the source, delivering water to the boiler and then taking the hot water into properties where it is used for heating.

Such schemes were popular in the United Kingdom in the 1960s and 1970s. Most came with a 50-year guarantee, meaning that many district heating systems are now reaching the end of their lifespan and parts subsequently need replacing.

This was the issue facing a local council in the north of England. Subsidence, damage caused by roadworks and underground flooding had led to corrosion causing several breaches to pipework within a district heating system supplying heat for a number of council-owned properties.

Water was leaking from a breach at the bottom of this section of pipe, caused by corrosion

Unfortunately for the council, the problem reached its nadir in the depths of winter. Replacing the leaking sections was therefore not feasible as it would have meant shutting the district heating system down for several days, leaving residents without any heat.

The council needed a pipe repair method which could keep the district heating system fully operational until the Spring, when the damaged pipes could be replaced once warmer weather arrived.

Sylmasta recommended the use of a SylWrap Universal Pipe Repair Kit to provide repairs temperature resistant to 200ºC and with the flexibility needed for such a challenging application, given the location of the pipework.

The pipes were located underground, requiring a flexible repair method that was effective in confined spaces

The pipes requiring repair were situated underground in extremely tight workspaces. Initially, the council had researched the possibility of using pipe repair clamps, but they realised very quickly that there would be insufficient room to manoeuvre and attach a heavy, bulky clamp to the pipes.

Working in such confined space was not a problem for the Universal Repair Kit. There were however some complications to overcome; one of the leaks was close to a welded joint which had to be worked around. Another was in a ‘low spot’ section of tunnel which remained flooded for prolonged periods of time, effectively leaving the pipe underwater.

Corrosion had caused breaches to underground pipe in a district heating system which required repair
The second section of pipe leaking from around a welded joint

This explained the considerable damage this section had suffered – several inches of insulation material surrounding the pipe had been eaten away – as the district heating system had not been designed to undergo such environmental stress.

Despite the numerous issues that needed mastering, the Universal Kit was able to successfully repair the leaking sections. Wrap & Seal Pipe Burst Tape was applied to seal the initial breaches. The tape was stretched despite the space limitation to three times its length, after which it fused to form a solid rubber band over the leaking areas.

SylWrap HD applied to corroded pipe in a district heating system as part of a repair application
Successful repair of the first section of corroded pipe

A SylWrap HD Pipe Repair Bandage was then wrapped over the top of the Pipe Burst Tape applications. SylWrap HD provided a rock hard, impact resistant layer to the initial repairs, helping to protect them from future damage caused by corrosion, building and maintenance works, or flooding of the tunnel in the low spot.

Any repair made with a Universal Pipe Repair Kit is permanent, giving the local council the option of relying on the SylWrap application if they wished to avoid going down the route of replacing the damaged section of pipe at a later date.

Badly corroded pipe in a district heating system undergoes repair with a SylWrap HD Pipe Repair Bandage
Wrap & Seal and SylWrap HD applied around the welded joint, sealing the leak on the second section

For future repairs to other district heating systems or pipes for which the council is responsible, Sylmasta recommended the use of the SylWrap Pipe Repair Contractor Case.

The Case contains enough products to make up to six live leak repairs at a cheaper cost-per-repair than buying individual Pipe Repair Kits. A Case can be easily stored on-site or on the van, meaning it is always to hand for whenever problems arise.

If you have an application you would like to enquire about, then please get in touch

Call: +44 (0)1444 831 459

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