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Modified Sliplining Eliminates Bursting Problems in Canvey Island
 Canvey Island, situated on the north coast of the Thames estuary to the west of Southend-on-Sea, is part of Anglian Water’s area of responsibility. Anglian Water is responsible for the clean water supply and wastewater sewer pipeline networks owned and operated by Anglian Water.
As part of a broader £700,000 refurbishment project at a local pumping station that serves the wastewater collection system in the area of Canvey Island, an asbestos cement pipeline which had a history of bursting problems and is located beneath Thames Road and Thorney Bay Road, Canvey Island, Essex, was required to be renovated.
Construction works were undertaken under a framework for Anglian Water by the @one Alliance. The Alliance’s partner, Barhale Construction plc, undertook project management planning, enabling works and supervision of the rehabilitation. As part of the planning process, all potential renovation techniques were investigated. The InsituGuard™ system, the non-disruptive, HDPE solution for pipe rehabilitation which includes the InsituFold™ installation process, was ultimately selected as the best solution to complete the work.
This system was selected due to its ease of installation and its close fit to the host pipe which enables the maximum pipeline flow capacity to be maintained.
INSTALLATION OF THE INSITUFOLD™ SYSTEM
Because the pipeline in need of rehabilitation was situated in mainly clay soils with a high water table, problems with prevailing ground conditions during the project were virtually non-existent.
 Once the ends of the pipeline had been accessed via pits excavated by Barhale, the length was decommissioned and surveyed by closed circuit television (CCTV) surveyed. This ensured Insituform that there were no obstacles, deformities or obstructions that would prevent the lining operation from proceeding, and eliminated any potential for lost time during the renovation operation. Insituform then set up its InsituFold™ machine to prepare the liner pipes.
In total, four liner installations were required, comprising the use of 435 mm diameter SDR 26 Black PE 100 liner pipe. The pipe was supplied and delivered by GPS PE Pipe Systems in 12 meter sections from St. Peter’s Road, Huntingdon Cambridgeshire. The four liner installations comprised lengths of 170, 237, 152, and 190 m respectively.
To complete the InsituFold™ lining operation, the required length of the liner pipe was first prepared by butt welding together sufficient lengths of the pipe. The welding system used was a McElroy Tracstar 618 ‘shelled down’ to suit the 435 mm diameter PE pipe. The McElroy unit was supplied by PSS (Plant & Site Services Ltd.) and operated by Insituform’s trained personnel who also completed the actual welding work. Once the welding was achieved, the pipe length was passed through the InsituFold™ machine which altered the shape of the pipe and resulted in a diameter reduction of up to 40 percent of the cross-sectional area. This shape was maintained during the pull-in process by using banding straps until it was fully installed in the host pipeline.
 After the InsituFold™ process, the HDPE pipes were fed onto a series of rollers for storage prior to lining. Once the full length of liner had been welded and had completed the InistuFold™ process, the HDPE pipes were aligned with the host pipe and the installation was commenced using a 10 t winch.
Once the liner was installed in the host pipe, water pressure is applied internally which reverts the HDPE back to its original round form. The banding straps break, allowing full reversion to be completed. The water pressure is held for a set time to allow the now re-rounded pipe to establish a close fit to the host pipe.
On Canvey Island, the works to complete the four lining runs commenced on 15 September 2008 with completion by 30 October 2008. Each of the individual liner lengths was installed in a single day.
According to Kevin Mussell, site agent for Insituform, “The project went very smoothly and there were no particular problems in the build up to or during the lining works. The preliminary CCTV work done by Barhale meant that we had to come in, clean the host main and complete a pre-lining CCTV inspection, prepare our liners and line the pipes. Our experience with the InsituFold™ system has now been developed to the point where once the pipelines are clean and ready to line our crews can effectively complete each run with minimum disruption to the local environment or residents. We also have a very good working relationship with Barhale, which over the years has gone from strength to strength.”
For Barhale, Richard Beecroft, contracts manager said of the project: “Insituform’s presentation of the technical advantages of the process prior to awarding the works was bourne out by the company’s performance on site. The Insituform crew worked well with our site teams to complete the installation in an efficient manner.”
Insituform®, Insituform Technologies®, InsituGuard™ and InsituFold™ and the Insituform® logo are registered and unregistered trademarks of Insituform Technologies, Inc. or its affiliates in the UK and other countries.
©2009Insituform Technologies Ltd
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