The Blairlinnans water main, owned and operated by Scottish Water, is a 42-inch pre-stressed concrete pipeline that runs over 16 km (10 miles) from the Blairlinnans Water Treatment Works to a service reservoir in West Dunbartonshire, Scotland. The pipeline was installed in 1974 and is integral to the ongoing operation of Scottish Water’s water network.
THE CHALLENGE
Like many water utilities, Scottish Water consider trunk mains to be among their most critical assets. Due to the high consequence of failure, Scottish Water recognised that the Blairlinnans main required a complete engineering assessment to understand the true condition of the pipeline.
The inspection showed most of the pipeline to be in good condition, although some pipe sections (around 2%) were found to have broken pre-stressed wires that are critical to support the integrity of the pipeline. Once a critical number of wires have broken in an individual pipe section, the main is at risk of catastrophic failure with potentially devastating impacts.
Replacement of major pipelines is often cost prohibitive, extremely complex and causes major disruption to customers while also creating significant carbon emissions. Furthermore, 2% of damaged pipes was not enough to warrant a complete replacement.
THE SOLUTION
To actively manage the integrity of Blairlinnans water main and extend the life of the asset, Scottish Water opted to install Xylem’s aoustic fibre optic (AFO) system, which allowed detection and identification of the precise location of any breaks in the pre-stressing wires as they occur. Xylem’s system enabled Scottish Water to make smart, evidence-based decisions about which sections of pipe need immediate repair and which sections can be deferred until later.
RESULTS
Inspections and monitoring have provided the ability for Scottish Water to:
- Reduce the risk of failure by pre-emptively maintaining areas known to be in poor condition.
- Achieve cost savings by extending the life of remaining pipe sections that show either no damage or low-medium deterioration.
- Minimise water supply disruptions to customers.
- Maintain the utility’s public reputation as a forward-thinking, reliable service provider.
- Reduce their CO2 footprint by offsetting emissions associated with pipeline renewal.
Xylem’s AFO system has proved to be a great success in remotely locating wire breaks which ultimately circumvent disastrous burst events. It not only equips Scottish Water with the data they need now, but it will also continue to support their future decision-making process.
PROGRAM HIGHLIGHTS
• A first of its kind within Europe
• Over 16 km of pipeline continuously monitored
• 2% of pipes found to have wire breaks
