A better approach to pressure pipe renewal

The water industry has been searching for renewal solutions optimised for pressure pipes. Pipeline infrastructure specialist Interflow shares how it developed a suite of sustainable renewal solutions to address this growing need.

Pressure pipes have traditionally been excavated for repair or replacement as water infrastructure ages. This has disrupted communities and increased costs and time scales.

“The Water Services Association of Australia (WSAA) found around 40,000 kilometres of asbestos cement pipe in Australia,” Will Zillmann, Interflow’s National Product Manager, said.

“When you dig it up, many precautions have to be taken, so the expense is significant. If you leave it in the ground and lay new pipe alongside it, you have to ensure nobody ever digs it up, adding more administration expense. There are a lot of issues.”

As corrosion from aggressive soils attacks underground pipes, including those made from cast iron, a trenchless renewal option for such pipelines becomes increasingly attractive.

What the pressure pipe renewal solutions look like

Zillmann said comprehensive renewal solutions should not just fix a specific problem but reset the pipeline’s lifespan. They should essentially perform like new products.

“Proactive trenchless renewals are one of the keys to defending our critical water and wastewater services sustainably and cost-effectively,” Zillmann said. “New or rehabilitated pipes can last decades, reducing the need for frequent interventions.

“Our objective was to build a suitable suite of proven solutions that enable us to match the right product or approach to the pressure pipeline’s condition, material, size and location.”

In response to the threats raised by the much-discussed infrastructure cliff and by the fact that a significant percentage of Australia’s water reticulation networks are made from asbestos cement, Interflow developed the Rediflow bundle.

Rediflow includes their Titeflow die-reduction lining as well as Infrastop line-stopping technology.

Together, the innovations provide a complete reticulation renewal system, empowering asset owners to conduct proactive renewal projects and dramatically reducing unexpected network shutdowns.

Trenchless: the most practical solution

The Rediflow bundle is at the core of Interflow’s suite of solutions and includes a polyethylene liner technology known as Titeflow.

It’s a structural liner thats diameter is reduced with a die during installation so it can be drawn into the host pipe. Once inside, it expands again to press against the host walls, creating a new pipe within the existing pipeline.

As a lining technology, it fits within the ISO classifications for trenchless solutions, primarily Class A (it can survive the failure of the host pipe and is a fully structural solution).

It’s a solution that balances performance, safety and environmental impact with the many benefits, including:

Reduced environmental impact: trenchless technology minimises environmental impact, especially compared to traditional methods that involve excavation along the line. It reduces emissions, creates dramatically less land disturbance, and reduces waste management concerns.
Lower community impact: the Titeflow method requires only limited excavation for access points, drastically reducing the need for road closures, which disrupt local communities and create unsightly trenches across the landscape.
Long-term cost efficiency: while trenchless methods may sometimes have up-front costs comparable to traditional dig-and-replace methods, they offer long-term financial benefits due to their durability, reduced maintenance needs, and shorter project timelines.

Zillmann said sustainable pipeline renewal methods will become the norm as the triple bottom line of environmental, social, and economic impacts becomes increasingly important to water authorities and the government.

How Interflow proved its suite of solutions

Interflow’s purpose is to improve lives, which extends to its communities and environments. This has led them on a journey to find, assess, and develop sustainable renewal solutions that support the needs of the industry, customers, and their communities.

On this journey, Interflow conducted an exhaustive and ongoing research project to ensure that the trenchless solutions deliver on their promises.

“To enable renewal programs and decrease the reliance on excavating and replacing ageing pipes, the water industry has been searching for renewal solutions specifically optimised for pressure pipelines that meet the needs of asset owners and their communities.

“We were active participants in WSAA’s Cooperative Research Centre for Smart Linings for Pipe and Infrastructure Project,” Zillmann said.

This involved water authorities, suppliers and delivery partners collaborating over several years to research and trial the effectiveness of emerging lining technologies for water and wastewater assets.

“This type of industry-led research is critical for objectively assessing technologies that are entering the Australian market for effectiveness and suitability, and for creating product documentation and decision tools,” he said.

From idea to reality

Through such research projects and working closely with customers, Interflow has pushed the boundaries of common approaches like slip lining and large-diameter die-reduction lining.

“For example, we’ve had success renewing longer lengths of water main using both technologies by thinking differently about how we store, string out and weld pipe sections, and facilitate insertion,” Zillmann said.

“Due to these approaches, we can now offer renewal options for pressure pipes in varying condition states and covering a large range of sizes and materials. Our approach to renewal opportunities is to be solution-agnostic and develop an optimal methodology based on project-specific network capacity needs, pipe condition and material, internal diameter, access constraints, budget and community needs.”

It’s being used right now

Interflow’s research led to using the trenchless pressure pipe solution in real projects, which further enhanced the data set used to inform the algorithm that predicts information such as pulling load, die size, insertion diameter, and more.

“The algorithm is where the real magic is,” Zillmann said. “If you get it right, everything will be relatively easy by the time you get to the site.”

Of course, there is always room for greater performance and more innovation, which is why the project is ongoing.

“We’re always working on optimising the solution’s performance because its main drawback is that it naturally reduces the diameter of the pipe,” he said.

“That can have an impact on flow capacity. But as long as we keep working on the materials and the algorithm, we can reduce that effect as much as possible.”

For more information, visit interflow.com.au