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Insituform Technologies’ Thermopipe® Keeps Isle of Man Rising Main Online
 The town of Ramsey lies towards the northern end of the Isle of Man. In the town, at Clifton Park, there is a sewerage pumping station pump that collects local flows before pumping them through a rising main for their onward journey to the local treatment plant. During part of the regular maintenance programme of the Department of Transport (DOT) – Drainage Division which is responsible for sewerage operations on the Isle of Man, an inspection of the rising main leading away from the pumping station revealed that it was becoming structurally unsound. As flows through the rising main pipe run at an operating pressure of 4 bar pressure rehabilitation works were called for.
Consultant Holmes Grace Consulting Engineering Ltd worked directly with the client, DOT, to design and formulate the works required. The main contractor working with Holmes Grace was Insituform Technologies Ltd (ITL). After careful consideration of the options available to renovate the pumping main, it was decided that ITL would utilise its Thermopipe® lining system for the project.
THERMOPIPE®
Whilst more commonly associated with clean water lining operations, Thermopipe® has been used in various locations across the UK for similar pressure main sewer work with companies such as Severn Trent, Scottish Water and Welsh Water. The process of lining with Thermopipe® offered the Isle of Man site not only a significant savings due to it’s rapid installation time compared to other systems (the liner does not have to cure it is simply heated and re-rounded), so minimising the downtime of the pumping station, but also provided a long lasting, thin-walled, structural liner which minimised the capacity losses after lining, making it ideal for pressure pipes of this type.
 Thermopipe® is a thin-walled, reinforced polyethylene liner that is ideally suited for rehabilitation of distribution water mains and other pressurised piping systems of up to 300 mm (12 in) diameter and up to 350m in length. The liner material is designed to be able to operate at internal pipe pressures of up to 16 bar. Supplied as a factory-folded ‘C’ shaped liner, the Thermopipe® liner is winched into the host pipe from a reel and reverted with air and steam. Once inflated and heated, the liner forms a close-fit within the host pipe, creating a jointless, leak-free lining system able to independently carry the full system internal design pressure. The installation process is simple and very fast with a single installation usually being completed within an 8-hour time period. The thin-walled nature of Thermopipe® means that even after lining there is virtually no capacity loss in the renovated pipeline.
RAMSEY PROJECT
On the Isle of Man project there was a significant amount of preliminary work that needed to be carried out prior to the lining operation. Working hours on the site were between 07.00 and 18.00. Due to the continuing operation of the sewage network feeding into the pumping station during the course of the preparation and lining works, an overpumping system had to be established to cope with the ongoing flows. This involved the use of road tankers which dealt with all incoming flows in Clifton Park whilst the pumping station was temporarily suspended for the necessary civil engineering and lining works.
The civil engineering works were carried out by S Craig & Sons, a regular subcontractor of ITL on the Isle of Man. These works comprised operations to access both hatchboxes and access pits which were excavated at strategic points on the rising main because of the existence of 45° and 90° bends along its route. At the hatchboxes this meant the removal of 1 m of the rising main pipe. The information on which this work was based had been obtained using initial CCTV surveys of the pipeline. Once the pipeline was prepared a further CCTV survey was carried out to ensure the line was clear of any potential obstructions before lining commenced.
LINING WORKS
The rising main project comprised a total of five separate liner installations using 250 mm diameter Thermopipe®. The installations included a 76.9 m length, a 152.5 m length, a 46.5 m length, a 42.5 m length and a 187.3 m length, giving a total lined length of 505.7 m. After each Thermopipe® insertion was completed a further CCTV survey was completed to ensure the quality of the lining and provide a record of the installation for the client. Once the lining work was completed the rising main was reconnected to the main sewer network and the pumping station put back into service. The contract, from start to finish, was completed in just 14 days.
 Commenting on the project Stephen Harrison, Chief Technical Officer for Ramsey Town Commissioners stated: “The lining works have now brought closure to the ongoing problem of failures of the pumping main, which had previously resulted in emergency procedures having to be adopted. The works were carried out under difficult conditions, with heavy rain occurrences, proximity of existing services and running sand ground conditions all being experienced during the course of the contract, however a co-ordinated approach by all parties ensured that the work was completed successfully and safely.”
He went on to say: “The installation of the Thermopipe® lining system has resulted in the refurbishment of a pumping main which would otherwise have had to be replaced, with the obvious disruption to landowners and nearby residents, together with major cost implications.”
ITL continues to expand its equipment portfolio to cover most aspects of the trenchless technology installation and renovation industry, enabling it to better serve the contracting needs of its wide and increasing variety of utility and industrial customers. For further information on any of the company’s available technologies please contact John Beech, ITL Business Development Manager using the contact details below.
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