Renovate sewer rising mains using the Primus Line^® system

22 Oct 2021

The renovation of sewer rising mains is often delicate. That is why operators are increasingly looking for trenchless rehabilitation methods. One of them is Primus Line^® – a tried and tested technology.

Many sewer rising mains have several things in common: They are a critical asset to the asset owner, as it is often complicated to divert the flow for an extended period of time. The accessibility to the pipe is mostly difficult, as the mains run through densely populated or environmentally sensitive areas or under creeks and main roads. The pipelines often have several bends in the run of the main. Faulty sewer rising mains have the potential to cause pollution, damage property and neighbouring services, resulting in significant costs.

Failures on rising mains can be caused by external corrosion, internal corrosion or mechanical failures like leaking joints, longitudinal cracks, etc. In many cases the pipeline is still able to withstand the traffic loads, but not the internal pressure loads. A renovation using swagelining or slipining with HDPE is often not acceptable due to the significant diameter reduction, the limitation of installing through bends, the pit sizes and the duration of the installation.

Remedy for the renovation of sewer rising mains – Primus Line^®

The Primus Line^® system, engineered and made in Germany, offers a solution for this extraordinary difficult scope. The system consists of a flexible Aramid-reinforced liner and special end fittings. Primus Line^® convinces with its small installation footprint, a wall thickness of only 6 millimetres, its flexibility to be installed through bends, also consecutive bends, the possibility to reline 500 metres and more in only one day, and achieve installations shots, pit to pit, of 1000 metres and more. In addition, Primus Line^® is installed with an annulus, thus the installed Primus Liner will accommodate the operating pressure and will release the host pipe from bearing the internal forces and therefore stop the aging process of the existing main caused by the operational loads and internal corrosion. The Primus Liner is a factory-tested product, that comes on a transport reel to the construction site. After CCTVing and cleaning the existing main, the prefolded liner is winched in position and inflated using only compressed air. Subsequently, the Primus Line connectors are installed and a pressure test completes the installation process.

Renewal of 635 metres of sewer rising main DN 500 in one single pull

The Primus Line^® system has already proved its suitability for rising mains in numerous installations. For example, a unlined DN 500 cast iron sewer rising main in Wollongong constructed in 1937, which has recently experienced multiple failures in rapid succession. A decision to urgently reline the main using the Primus Line^® system was made to prevent failure reoccurrence. Civil works including the relining works were carried out by Sydney Water’s internal crews with assistance of Primus Line’s certified partner Interflow. The golf course, where most of the main is situation, remained open during the entire project phase. The Primus Liner was pulled in over a length of 635 metres in one section below the course, a busy road and a body of water. A 70-degree bend was also passed through in the process.