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Innovative "triple line" approach makes water works quicker and easier

For the first time in Australia, one NSW utility has used a trenchless "triple line" method to repair a broken water main, avoiding the extensive disruption of digging near a busy Newcastle thoroughfare.

The Hunter Water project involved installing three flexible liners into the pipeline, using Primus Line technology, a method that has only before been used in Europe.

Hunter Water Service Delivery for Customers Executive Manager Glen Robinson said the decision to use innovative trenchless technology has been very successful.

“The success of this project has been testament to the collaboration of all parties involved, both within the planning and operations teams at Hunter Water, and with our contract partners who helped us in the manufacturing and delivery,” Robinson said.

“From extensive research and planning, right through to the implementation, this approach resulted in a great outcome for both Hunter Water in the repair of our water main, and for our customers and community in minimising disruption.”

By adopting this method, Hunter Water was able to deliver crucial water works to the Newcastle community without disruption.

“Our civil maintenance crews were able to access the pipe by digging two trenches, three metres deep by seven metres long, on either side of the break location. This meant there was no need for significant road closures or traffic disruption to our community,” Robinson said.

Robinson said Interflow helped with the installation of the Primus Line technology, which involved a week-long process of concurrently threading three flexible, reinforced liners into the water main from small trenches, inflating them using compressed air.

“Using three smaller 450 millimetre liners presented us with the best option for maximising the flow capacity of the pipeline, when compared with using a single 500 millimetre liner, which would have granted us just 25% of its use,” Robinson said.

“The liners were then connected to the remaining pipeline with purpose-built manifolds. We were able to work with a local manufacturer to design and make these end fittings, which was a core component of the project.”

With the construction phase taking just eight weeks, Robinson says the project has opened up a new way of approaching mains repair for the utility and that he looks forward to seeing the technology used further.

“This project has demonstrated that innovation can open the door to new, better ways of doing things. We certainly hope to take the lessons learned from this job and see what we can take from it for future projects,” he said.