Apr 2019
Gas Distribution
Composite repairs for through wall defects on metal pipes
Apr 2019
Mar 2021
Cadent Innovation Team
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Network Innovation Allowance
GD - Repair
Gas Distribution Networks
Above ground pipework is exposed to the elements, resulting in possible degradation from corrosion; known as external metal loss. Support structures can concentrate rates of corrosion around the pipe as they often begin to corrode before the pipe. This technology can offer the potential of a permanent repair to pipe and reduce the number of costly replacements. A permanent repair will also offer significant reduction in environmental impact and reduce large scale works, protecting staff from higher risk activities and the public from increased disruption.
1. Develop a standard design method for a composite repair for deployment on the low and medium pressure systems (including thermal and self-weight loads) where the damage has:
• not yet gone through-wall.
• resulted in a leak.

2. Measure bond strength achieved on cast iron, spun iron, ductile iron and steel lines prepared by both bristle blasting and hand tools.

3. Analyse several stop – gap methods and quantify their capability to provide the temporary relief and also their suitability for use with a composite repair.

4. Quantify the energy release rate achieved between composite repairs to iron pipes.

5. Verify the proposed qualification framework is suitable and sufficient for identification and validation of repair approaches for iron lines.
In the current state Cadent repairs iron pipelines using a full encapsulation epoxy filled steel shell, which for an IP main costs £179,100. It is anticipated that the new repair techniques will reduce this cost to £50,664.
This cost reduction assumes that a composite repair in iron pipelines will mitigate the need for bespoke fittings and will prevent loss of supply for our customers.