PRISM (Pipe Replacement in situ Manufacturing) - Material Lifetime Testing
National Grid Gas Distribution
NGG PRISM Programme Manager – Brian Tilley
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Network Innovation Allowance
Gas Distribution Networks
As the host pipe could potentially fracture the day after PRISM application or tens of years later, consideration needs to be given to the impact of ageing of the applied resin. The testing will need to consider the saturation and ageing of the resin in a gas main environment and this will be undertaken separately by 3M, the manufacturers of the resin. The focus of the study outlined in this project submission will be to assess the suitability of the applied resin layer for use as a long term stand-alone pipe as more of the PRISM pipe becomes exposed to the surrounding environment following the continuing deterioration of the host pipe.
Further testing will also be undertaken to establish the ability of the applied resin layer to withstand the external loads which could be applied if the external water table is high. The resistance of the resin layer to collapse from external loading is related to the long term stiffness of the resin material and this will also be established separately by 3M through a series of laboratory tests which establish test times for a range of loads which can be extrapolated to provide a modulus value for 50-year life. The focus of the study outlined in this project submission will be to establish the resistance of the applied resin layer to external buckling, its ability to contain internal pressure and also its ability to accommodate any thermal expansion and contraction expected during the lifetime of the installation.
The completion of these tests will provide a key determinant in the assessment of the technical viability of the PRISM solution.
Of the two reports being produced from this project, the first will provide interim confirmation of the ability of the applied resin layer to resist the initial internal and external loading as the host pipe begins to deteriorate and fail. This will inform a decision to continue with the remaining programme activities. The second and final report will complete the assessment of the ability of the applied resin layer to continue to resist the applied loading throughout the lifetime of the installation. This will confirm that the lifetime of the resin material is sufficient to validate the technical and commercial viability of the solution, leading to full commercialisation.