Insituform Technologies Ltd successfully installed 165 meters (540 feet) of 300mm (12-inch) Primus Line® material into a rising main in Whitstable, Kent for Southern Water. Since the inception of the relationship between Insituform and the Primus Line® distributor, Insituform has been able to install about 5000 meters (16,400 feet) of the Primus Line® material in various diameters throughout the UK.
Primus Line® is a flexible sliplining solution for the trenchless rehabilitation of pressure pipes. The system consists of a flexible Kevlar® reinforced liner and specially developed end fittings. Primus Line® is not bonded to the host pipe, is self-supporting and allows an annulus to remain between Primus Line® and the host pipe.
Southern Water had a failing 300mm PVC rising main located through gardens and parallel to a railway embankment. They had been searching for a rehabilitation option with minimal excavation requirements as the main is approximately 2.5 meters deep and access for machinery is very limited. The length requiring immediate attention was 165 meters in length underneath gardens. Access at the pumping station end of the pipe was good within a car park, but the downstream end was limited due to it being in a customer’s garden.
The ground profile also rose along the route, with no air valves or washouts recorded on their GIS. The static head from pump to discharge was 32 meters. The friction head losses at a designed pass forward of 125 l/s was 8.9 meters adding an allowance for bends and valves the operational pressure was deemed to be 4.3 bar (60+ psi) and pressure tested to 9 bar (130 psi) post installation. The station has three pumps operating duty/assist/assist. It had combined flows so was unlikely to run at design output except in heavy rainfall. This was suspected to be the cause of its current failure.
Insituform worked collaboratively with Southern Water, their supply chain and Primus Line to develop an effective and economic trenchless rehabilitation solution. Southern Water had already committed to setup flow management prior to Insituform carrying out the initial site survey, this enabled all stakeholders to define the final scope and to develop a seamless programme of works to mitigate unnecessary downtime.
The Primus Line® material was delivered directly to site as a jointless length of pipe on a drum. A winch was set up at the receiving pit with the winch wire being installed. Once installed the connectors were attached and a pressure test took place which was witnessed by the client.
Day 1 – clean pipework, setup winch
Day 2 – Pull through Primus Line® material
Day 3 – Install connector and carry out pressure test.
Working closely with the client on design, planning and delivery contributed hugely towards the project being delivered on-time and to budget.
Southern Water County Manager, Jean-Paul Collet explained, ‘Working in partnership with Insituform on the project at Whitstable, really demonstrated the power of collaborative working. Insituform and the colleagues they provided to carry out the installation were professional, courteous and extremely knowledgeable. The installation itself was completed on time and to a high standard. Thank you to all at Insituform who were involved in the delivery of this project’
The job was successfully completely thanks to the combined efforts of the dedicated Insituform installation crew, Primus Line and the support of the client organisation.