A rare and complex repair to a damaged high-pressure gas pipeline has been successfully carried out, ensuring the continued and safe supply of gas to numerous homes.

The urgent remedial work was initiated following an inspection in September of last year by the Scottish Maintenance team on the Baillieston to Motherwell pipeline. During the inspection, a pipeline inspection gauge (pig), used for internal assessments, encountered an obstruction.

Data retrieved from the inspection tool revealed a significant dent in the pipeline, which was not present during a previous inspection. Following a reduction in the pipeline's operating pressure, an above-ground survey was conducted to pinpoint the location of the damage. Subsequent excavation confirmed the presence of a substantial dent, prompting preparations to isolate the pipeline for repair.

David Wylie, Pipeline Engineering Manager, emphasised the critical nature of the infrastructure: "Our LTS network is critical infrastructure so we do regular surveys and inspections to ensure we can continue to operate it safety."

-- Advertisement --

He highlighted the collaborative effort involved in the repair process: "Before we began the repair on the Baillieston to Motherwell pipeline, there were a lot of moving parts and lots of input from many across the business. Colleagues in Major Projects assisted in sourcing replacement pipe to be tested and prepared, our southern Maintenance colleagues assisted in facilitating and witnessing the pressure test on the replacement pipe at one of their sites, and specialist contractors actioned weld procedures and resources for the cut out and replacement. In the meantime, the Pipelines team did what they do best and set to prepare the cut-out location."

Once the pipeline was safely isolated, the damaged section was removed and replaced with a new piece of pipe, which was then welded into place. These welds, known as ‘Golden Welds' due to the enhanced inspection they undergo after hydrotesting, were completed to a high standard.

With the repair finalised, the pipeline was recommissioned and returned to its normal operating pressure.

Mr Wylie noted the unusual nature of the repair: "This was an unusual example, as having to cut out damaged sections of pipeline is very rare. In most cases we can carry out repairs without taking the pipeline out of service."

He commended the team's efficiency: "I'm very proud of the fact the whole team, led by Pipeline Engineers Andy Stewart and Mark Anderson, managed to turn around the whole process within three weeks of finding the damage."

The Local Transmission System (LTS) in Scotland comprises over 1,300km of high-pressure pipelines, operating at pressures up to 85 bar and supplying gas to distribution networks. The company conducts regular inspections, with eight carried out this financial year, each presenting unique challenges in terms of planning and analysis to determine the optimal time for inspection. Due to the tool's speed being dependent on gas flow, inspections often require overnight work to accommodate demand conditions.