Working with Colus Ltd and CPC on behalf of Severn Trent Water, Sanivar recently installed the first ever 450 mm diameter pull through SaniTube liner, a world first for this diameter.
In a challenging environment with the potential for high customer disruption amongst business and residential stakeholders, the project at Cheslyn Hay, near Cannock, UK demanded a unique solution that provided both structural integrity and high resistance to abrasion.
The project required the refurbishment of a 180 m long section of 500 mm diameter rising main, which could not be replaced using open cut methods as its course ran through an industrial estate and under above-ground infrastructure, including aquatic tanks and commercial greenhouses.
On account of the main’s high abrasion levels, the cast iron pipe, which was approximately 50 years old, had worn to a depth of 10 mm. The aggressive environment and high operating pressures meant that the lining solution needed to offer structural integrity, resistance to pressures from -1 to 10 bar and resistance to abrasion.
SaniTube offered the required level of abrasion resistance but despite withstanding pressures of up to 16 bar, is not a full structural liner. The newly launched 450 mm diameter liner can inflate to 490 mm diameter under 5 bar pressure, which is sufficient to meet flow requirements. A structural liner was then installed to restore asset integrity and to meet the abrasion resistance. To protect the relined asset, SaniTube was used as a sacrificial liner.
An 8 mm thick Berolina HF liner was used to restore structural integrity to the main and after analysing the potential of transferring negative pressure from one liner to the other it was decided that SaniTube offered the optimum protection against abrasion and negative pressure.
Due to the excessive mitigation involved in tankering from the pumping station, there were cost implications associated with having the main offline for a considerable amount of time, so both CPC Civils and Colus worked around the clock to minimise completion time.
Works began with Colus providing a JHL super recycler, UHP cutter and mainline camera team. The cleaning of the cast iron pipe was conducted successfully, with the camera ensuring that the pipe was completely clean and that no further damage had been incurred.
Just 24 hours later the pipe’s UV liner was installed, cured and cut out in preparation for the installation of the 450 mm diameter SaniTube the following morning.
The final part of the project was conducted by Colus’ specialist pressure pipe lining team, which started the installation process of the 450 mm diameter SaniTube. Once in place and expanded to the manufacturer’s guidelines, the team got to work fitting the SaniGrips, which hold the liner in place.
Tim Farley, Business Development Manager at Sanivar, said: “This complex project demanded an innovative solution and the flexibility of SaniTube made it the optimum choice to provide a total solution that restored structural integrity, provided abrasion resistance and critically minimised costs and customer disruption.”
The works were started and completed in less than 60 hours. During this time, the team managed to rehabilitate the host pipe and extend its life span by 80 years, as well as installing a unique SaniTube product with a minimum life span of 25 years against abrasion.