Ryan Shallenberger

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ISTT Award for SEKISUI Rib Loc and Interflow

23. August 2010

Together with the technology provider SEKISUI Rib Loc, Interflow has won the coveted ISTT No-Dig Award 2010 in the category “Trenchless project completed”. This international prize honours a construction project that set a world record: in Sydney, Australia the two companies rehabilitated a continuous 706-metre stretch of sewer with a diameter of 2,400 mm.

The International Society for Trenchless Technology (ISTT) has been presenting the NO-DIG Award for notable achievements in trenchless pipe rehabilitation since 1986. This year’s award winners in the category “Trenchless project completed” are Interflow and technology provider SEKISUI Rib Loc. “We are delighted to receive this prestigious award in recognition of our work,” says Geoff Weaver, Managing Director of Interflow. The award winners more than satisfied the jury’s criteria: “We were honoured for a construction project that was in many respects a first in trenchless pipe rehabilitation by spiral-wound pipe lining technology,” says Edmund Luksch, President of the international SEKISUI SPR Europe Group, whose subsidiary SEKISUI Rib Loc supplied the technology for the project. Both Interflow and SEKISUI Rib Loc achieved what was seemingly impossible and in response to the challenging conditions and expectations of its client Sydney Water they introduced innovations that have advanced the industry.

The project in brief
Interflow was contracted to renew a main 2,520 mm collector in Sydney, Australia and in response SEKISUI Rib Loc manufactured the profile. The world record liner has a diameter of 2.4 m and a length of 706 m. The spiral-wound pipe liner was produced for the renewal of the North Georges River Submain (NGRS), an important part of the sewer network of Interflow’s client Sydney Water. Interflow received the contract to reline and rehabilitate sections of this pipeline, whose total length is 5,438 m. The project began in June 2008 and was brought to a successful close in May 2010.

Innovations in manufacturing and installation
The first challenge was to supply a liner of the required dimensions, the second was to install it with unusually large distances between the existing manholes. The product choice was SEKISUI Rib Loc’s SPRTM PE, a unique, steel-reinforced liner made of high-density polyethylene for which a special for which a special composite profile was designed. This is the only product in the market taht is stiff enough to withstand the apllied loads in this diameter. The pipe liner was formed in-situ by spirally winding strips of composite profile together using a winding machine from inside an existing access chamber. The size and length of the spirally wound liner, which is brought into place by a stationary machine, is determined by two factors: the torque of the spiral winding machine and its ability to override the frictional forces caused by the spiral movement of the newly wound lining in the pipe. To enable the liner to be installed over a continuous length of 706 m, Interflow developed an innovative technology to reduce this friction: during the spiral winding procedure the liner was floated on the water flowing through the pipe. The technology also requires control of the water levels, in order to ensure optimum buoyancy of the liners on the inside and outside.

Under these demanding conditions, Sydney Water forced the industry to face a challenge – and it has triggered a pioneering solution. The contributions from customers, contracting partners and technology suppliers have all been instrumental in the success of the project, which has now been endorsed by the ISTT Award.