Scott Pearson, Works Manager at Green Cat Contracting Ltd (which installed the pipework) said: “We have been working with Keyline for seven years and trust in the team’s expert knowledge of the industry and its products. Across every project, Keyline works to ensure that the most suitable solution is specified, and the specific requirements of every brief are accommodated. The products that the Keyline team specified for the Glenample Hydro Scheme are testament to this.”

To ensure the correct specification, Keyline had to take into account a number of considerations. As well as external factors - including whether the pipes could hold the weight of the soil compacted around them and ensuring the safe delivery of the materials to this unique site, Keyline also needed to make sure that the pipes chosen were incredibly durable and able to withstand the water pressure. This was particularly vital for the pipework near the bottom of the hill, where pressure can reach up to 40bar. 

At the Glenample Hydro Scheme, 1,640m of underground pipework will collect and carry rainwater as it travels downhill. It will pass through a turbine and a generator to produce energy that goes back to the national grid to power homes across the UK.

Knowing this, Keyline selected two different types of pipe. Westwood Pipelines’ High Performance Polyethylene (HPPE) Pipe and fabricated fittings were used for the installation at the top of the hill - where the water pressure is at its lowest. Due to the material used, HPPE pipe is a cost effective choice. It is durable, lightweight and can be supplied in long lengths. For the Glenample Hydro scheme, the HPPE pipe ensured a straightforward installation process, reducing labour costs. This meant Keyline was able to keep the overall cost of materials down and in-line with the project budget.

Further down the hill, Hambaker Pipelines’ Ductile Iron Pipe and fabricated fittings were chosen. Iron pipes are incredibly strong and durable, which is ideal for transporting fast moving water as they can withstand high water pressure. Due to their strength, iron pipes will not damage during handling or installation and, once installed, will easily take the weight of external forces such as soil and wildlife. This means that they have a long life cycle. 

As well as water pressure, the Keyline team also had to factor in external forces such as the weight of the soil and turf around the pipes – and whether there was anything in the soil that could damage the pipework. For example, during the early stages of the project the Green Cat Contracting Ltd team noticed that the existing soil at the top of the hill included rocks that could puncture the HPPE pipework once compacted around it. Due to the logistics of the site, the team could not import soil from elsewhere – and instead used suitable soil from around the work area to replace it and ensure no damage would be caused. 

Mark Reid, Utilities Regional Sales Manager at Keyline explains more: “Another key consideration for us during the specification stage was the transportation of materials. Due to the location of the site, our fleet was unable to deliver directly to the working area. Instead, a helicopter was required to transport the pipes from a safe location and across the hillside. Therefore, the pipework chosen had to meet the strict weight restrictions of the helicopter, to ensure that the pipes could be safely lifted and maneuvered. We also had to adopt a ‘just-in-time’ approach to deliveries, as the team were unable to store materials on site.” 

Working with the team at Green Cat Contracting Ltd, Keyline Civils Specialist has supplied the ideal solution for this complex project.

To find out more about please contact a colleague at your nearest branch visit: www.keyline.co.uk/branch-locator.