In 2022, DrainTech Solutions became the first company in Australasia to deliver rehabilitation of a pressurised wastewater pipe with SAERTEX-LINER® MULTI Type S+XR.

DrainTech Solutions (DTS) took the innovative steps to reline more than 250 m of a recently installed pressurised wastewater pipe located inside the tunnel network infrastructure to increase the technical service life and future proof the pipe against corrosion.

As a pressure line, it had to withstand operating pressures up to 7.06 bar and meet the expectations of the client with a minimum 100-year design life expectancy. The time sensitive reline was part of Transport NSW scope of work on the M4-M5 Tunnels project that was nearing completion.

The DN 315 host pipe was made up of sections of stainless-steel pipe which carried contaminated ground water. Due to the complex location of the host pipe and the aggressive nature of the medium present, DTS conceptualised and executed an innovative plan by removing the host pipe completely from within the tunnel infrastructure and transferring it to an offsite warehouse, minimising impacts to other project works ahead of the tunnel opening and reducing safety risks to their crew.

The pipe was dismantled into 36 sections and individually relined using UV-CIPP technology. The crew of 8 then fit each individual relined section with end seals to allow the pipe to be easily dismantled in the future if required. DTS took this unique approach to allow for a targeted rehabilitation to be undertaken in the future if sections of the pipe became compromised overtime once the tunnel network was opened.

Selecting the appropriate liner for the project was critical in their mission to prolong the technical service life of the pipe as there were catastrophic and costly implications for the tunnel if the pipe failed. The liner was selected as it offers a 100-year design life expectancy. The production of this liner in Germany is also meticulously monitored for quality assurance, with no risk of exposure to contaminating materials and uses a climate-friendly manufacturing process for its UP-resin systems saving CO2 emissions during production.

The liner is also fully structural which was critical on this project where the client needed to antiCIPPate the networks future requirements. This liner would remain intact regardless of whether the stainless-steel pipe around it became compromised over time in this unique underground environment.