New liner technology rehabilitates water mains without trench-digging
Picture it… it's summer in the city and the streets are torn up. Sidewalks are closed and traffic is diverted. Retailers and restaurants are losing business, and already busy streets are becoming a traffic nightmare. If that wasn't bad enough, now imagine the same scenario, except it's the middle of a freezing cold Canadian winter.
For city dwellers, this is an all-too-familiar experience. Our water is supplied via enormous underground networks of water main pipes, which can develop leaks as they age, putting pressure on cities to spend millions on repairs and replacements. This can involve digging long trenches to get at aging pipes, potentially tying up traffic for months in some cases.
"The new solution is a woven composite liner in the form of a tube that fits into water mains 300 to 600 mm in diameter," explains David Trudel-Boucher, polymer composite specialist for the NRC's Automotive and Surface Transportation Research Centre. "To perform rehabilitation of the water mains, it is then only needed to dig holes 100 to 150m apart, or more, instead of excavating whole roads."
Essentially, a liner tube is placed inside the damaged water main, allowing targeted repairs to be completed at regular intervals, instead of having to dig up the entire section of pipe. While this may sound fairly simple in theory, in practice the challenges can be substantial. Similar technology already exists for smaller pipes, but for city water mains, it was necessary to develop composite materials that would be strong enough to withstand the water pressure that flows through large pipes. Aside from optimizing the repair process, this new technology also lasts as long, or longer, than new piping.
"We had to create a new hybrid fabric architecture for seamless, circular woven tubes that are really tough, yet thin enough not to impede water flow," says Trudel-Boucher.
In close collaboration with Sanexen, the NRC manufactured and tested various hybrid composite architectures in their lab. Ongoing conversations and regular visits to each other's facilities helped to ensure that the solution would be realistic and cost effective throughout the process, from the fabrication of the liner to installation in the field. In addition, the CDCQ contributed to the development of the large-diameter Aqua-Pipe technology by performing characterization tests of the post-installation of circular woven prototypes.
And the team effort has paid off. Niedner has filed a patent application and leveraged the technology to develop innovative products for other industries including mining and oil. Meanwhile, Sanexen has gone to market with the liner, using it in Montreal and Toronto, and in important U.S. markets. The company estimates that, by 2021, it will see a 20% increase in sales of large-diameter liners across its various markets, including Canada, the United States and Australia. To that end, it has installed a new manufacturing line that will ensure production stays in Quebec and continues to generate local employment. In addition, the project was nominated for a 2019 Innovation Award with ADRIQ (Association pour le développement de la recherche et de l'innovation du Québec).
Flowing into the future
"The success of the project illustrates how well the NRC's skills can be transferred to industry," says Trudel-Boucher. "When companies have an issue, they're looking for certain expertise… If we have the power to solve a problem anywhere in the NRC, we'll transport those solutions to industry to create new business opportunities."
And it's this sort of collaborative approach that will certainly help keep innovation flowing for Canadian engineering and technology long into the future.