Groundworks; Heating, Ventilation & Services Ultra high pressure jetting a concrete removal ‘gamechanger’ A


specialist team from drainage and wastewater specialist Lanes Group plc has prevented the need to partially demolish


three houses by using a water jet to remove concrete from a sewer pipe. Te ultra-high pressure (UHP) jetting system,


which powers the water jet to over the speed of sound, was deployed aſter the foundation concrete in the pipe proved too tough for conventional robotic cutting. Te only practical alternative would have been


to excavate and replace the pipe, buried three metres beneath extensions built behind the row of nine terraces homes in Ilford, north east London. Tat would have involved the extensions for


three of the homes being all but demolished, then reinstated, with the occupants placed in temporary accommodation while the work was done. Lanes carried out the UHP jetting project on


behalf of Tames Water and has now used the technique to complete other challenging concrete removal projects for the water company. Lanes operations manager Calvin May said:


“Tis was one of the toughest concrete removal projects we’ve ever tackled, and involved contamination of a 150 mm diameter sewer.” “We believe the concrete may have been linked


to a nearby building project. Foundation concrete is particularly hard and, in this case, had time to set solid, completely filling the pipe for 11 metres.”


HMM12_Lanes Group_Groundworks - Drainage_HPAdv.indd 1 “We didn’t make very fast headway with a


robotic cutter, which works by grinding down the concrete, so we needed a different approach.” “UHP jetting turned out to be a gamechanger.


It was over 20 times as fast as using robotic cutting and prevented the need for an alternative solution that would’ve been much more costly and disruptive.” It meant the concrete could be removed in 15


shiſts, equivalent to three weeks’ work. Lanes, Tames Water’s wastewater network


services maintenance partner, developed a business case for using UHP jetting to ensure it would work and be cost-effective. Tis led to the initial hiring of a UHP jetting


system to ensure the concrete removal process was effective – not least because a tanker was having to


visit the site every day to remove sewage building up behind the blockage. Lanes selected a Falch UHP pump combined


with an IMS Robotics jetting system, capable of delivering a water jet at 2,500 bar (over 36,000 pounds per square inch). Six Lanes wastewater operatives underwent


Water Jetting Association hydrodemolition training and equipment supplier instruction to give them the knowledge and skills needed to operate the system. Te UHP jetting system has a jetting nozzle


on the end of a hose encased in a flexible steel coil sheath. Once guided into the pipe, a packer is inflated with compressed air to hold the nozzle firmly in place inside the pipe. A mini camera and powerful LED lights


allowed the Lanes operative to then view the jetting operation, while controlling the nozzle with a joystick to direct it most effectively at the concrete. Te concrete was removed in one-metre


sections, with the exposed pipe strengthened by installing a cured in place pipe (CIPP) point liner made from fiberglass matting, impregnated with resin. Once the resin had cured, the liner created a


durable new concrete-free pipe within a pipe, with a design life of at least 50 years.


0800 526 488 www.lanesfordrains.co.uk 13/12/2023 12:04


26 | HMM December/January 2024 | www.housingmmonline.co.uk


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