AMEX-10 seal repairs hydroelectric pipeline

PMP was recently appointed by AMCO Construction to carry out pipe joint repairs to a number of joints on a buried pipeline. The pipeline forms the penstock for one of Scotland’s newest hydroelectric schemes at Kingairloch, located on the East side of the Morvern peninsula, 23 miles south west of Fort William.

Kingairloch Hydro Scheme has a generation capacity of 3.5 megawatts with a gross operating head of 143m. The scheme is located on the Kingairloch Estate on the Morvern Peninsula within the Abhainn na Coinnich river catchment. It includes a storage reservoir at Loch Uisge with water diverted from a number of tributaries of the Abhainn na Coinnich.

The pipeline includes approximately 4,500m of buried pipeline made up from approximately 3,500m of 1200mm Ø and 1,000m of 900mm Ø. The pipeline is buried in a trench over upland terrain at variable gradients up to 50% (1:1) and is rated between PN 6 and PN 25. The pipeline had to be laid to very tight dimensional tolerances. Subsequently a number of the joints between sections of the pipeline were discovered to not conform to the very high specification.

AMCO Construction contacted PMP for a solution to the out-of-tolerance joints. PMP proposed using the AMEX-10 seals, a low profile mechanical seal for internal pipe joint repair. A robust section of rubber that spans the joint is installed using hydraulic expansion of stainless steel compression rings, eliminating the use of chemical adhesives and their associated hazards. The seal accommodates substantial joint movement and is abrasion resistant. Each seal has an independently verified life expectancy of more than 50 years.

PMP engineers used roped access skills to install the unique AMEX-10 seals from within the pipe. By completing all repairs internally, trenching and service costs were avoided. The Kingairloch Scheme presented PMP with difficult working conditions. PMP’s Stephen Taylor explained that roped access was required to reach the pipeline joints. Working from a removed section of the 900mm pipe, the PMP engineer was lowered to the location of each leaking joint, in order to carry out the preparation and installation of the seals. In total 28 seals were installed over a period of 2-3 months.

Paul Owen, Contracts Manager for AMCO, commented: “PMP did a superb job in arduous conditions. Their service was very effective with a rapid response.”