Infrastructure innovation: better approach to pressure pipe renewal

The water industry has been searching for renewal solutions specifically optimised for pressure pipelines. 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 timelines.

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

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

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

What the pressure-pipe solutions look like

Comprehensive renewal solutions should not just fix a specific problem, Zillmann said, but also reset the pipeline’s lifespan. They should essentially function as a new product.

“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 for 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 the fact that a significant percentage of Australia’s water reticulation networks is made from asbestos cement, Interflow developed the Rediflow bundle. Rediflow includes its 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 reduce unexpected network shutdowns.

Trenchless: The most practical solution for aging pressure pipelines

The Rediflow bundle is the core of Interflow’s suite of solutions and includes a polyethylene liner technology called Titeflow. It’s a structural liner whose 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 withstand 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 significantly less land disturbance, and alleviates waste management concerns.
Lower community impact: The Titeflow method requires only limited excavation for access points, drastically reducing the need for road closures that disrupt local communities and create unsightly trenches across the landscape.
Long-term cost efficiency: While trenchless methods may sometimes have upfront 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 that sustainable pipeline renewal methods will become the norm as the triple bottom line of environmental, social, and economic impacts becomes increasingly crucial for water authorities and the government.

How Interflow proved its suite of solutions

Interflow’s purpose is to improve lives, which extends to their 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, and to ensure that the trenchless solutions do what they promise, Interflow ran an exhaustive and ongoing research project.

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

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 by working closely with customers, Interflow has been able to push the boundaries of common approaches such as slip lining and large-diameter die-reduction lining.

“For example, we’ve had success renewing longer lengths of the water main using both technologies by thinking differently about how we store, string out, weld pipe sections, and facilitate insertion,” Zillmann said. “Due to these approaches, we can now offer renewal options for pressure pipes in various 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 the use of the trenchless pressure pipe solution in real projects, which further enhanced the dataset 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 continues.

“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 minimise that effect as much as possible.”

For more information, visit https://www.interflow.com.au/