April 20, 2016
When managing drinking water pipes, the stakes are high and trying something new is never easy. But standby solutions might not provide the flexibility needed to manage budgets, unanticipated conditions and customer expectations.
A part of Yarra Valley Water’s ongoing infrastructure renewal program is a search for ways to improve the versatility, cost and quality of their service. Traditionally, two methods are used to rehabilitate the water mains, pipe replacement and bursting. But, in 2015, the organization decided to try something new.
Yarra Valley Water is Melbourne’s largest water and sanitation business, providing service to more than 1.7 million people and 50,000 businesses in the city’s northern and eastern suburbs. They also have a mix of pipe materials and diameters to address. The versatility of a single solution that could improve service and extend the life of both asbestos cement and cast iron pipes appealed to them.
As an option to address these needs, Yarra Valley decided to pilot 3M Scotchkote Pipe Renewal Liner 2400. This quick-curing polyurea formulation has been used successfully in North America and the United Kingdom. It’s an apply-in-place pipe liner that helps protect water quality from the effects of corrosion and tuberculation (which can lead to color, taste and odor issues) and cement leaching. It also helps extend service life of potable water pipes.
Scotchkote Liner 2400 can be used to maintain internal pipe diameters and repair certain cracks, pin holes and corrosion pitting. Plus, it works with a variety of pipe materials, including ductile iron, cast iron, PVC and asbestos cement.
In addition, an applicator can vary the product thickness based on pipe conditions. For corrosion protection, a thin lining can be applied. However, if the pipes require some internal pressure containment, the lining thickness can be increased.
Versatility is a strong asset, but it was only part of the reason Yarra Valley Water was interested in the solution. In a highly populous suburban area, rerouting traffic to make extensive repairs is undesirable. Every second that a causeway is out of service or congested, it costs money. Shorter projects are better for everyone. Scotchkote Liner 2400 is quick-curing polyurea liner with a 10-minute set time for CCTV inspection, a 60-minute full cure and a typical final flush time around 30-minutes — for a total time of as little as 90 minutes. This means Scotchkote Liner 2400 can be applied and the pipe reinstated in less than a day, per local regulations.
“The overall renewal process is much quicker, as the design and approval process is simpler and excavation is minimal. This means we can reduce the inconvenience to our customers,” commented Glenn Wilson, general manager of infrastructure services, Yarra Valley Water.
The site chosen for Yarra Valley Water’s pilot application was located underneath roadway pavement. By using Scotchkote Liner 2400, the water company needed only a 6-ft by 8-ft pit on each end of the pipe section and did not have to break up and excavate the remaining pavement — a disruptive, time and labor-intensive process.
Only 3M authorized applicators can apply Scotchkote Liner 2400. 3M works closely with applicators and provides extensive training and support. In Australia, 3M’s authorized applicator is Abergeldie Watertech, who worked with Yarra Valley Water on the pilot project.
After the excavation of the launch and retrieval pits, the interior of the pipe is cleaned. A number of cleaning processes may be used, depending on the pipe material, diameter and condition. Then an interior pre-lining inspection is done via closed-circuit television (CCTV) typically using a pan-and-tilt camera. The inspection verifies that the pipe is clean and dry, locates service connections, and provides input on the condition of the pipe.
Next, Scotchkote Liner 2400 is applied using a spin-cast spray head pulled through the length of the pipe segment. The CCTV post-lining inspection takes 10 minutes and ensures that application meets requirements. In as little as 60 minutes, the lining cures to the point required to reintroduce water. The mains are then flushed, undergo disinfecting and water testing according to local requirements and, upon passing, can be returned to service.
“Customers can also experience reduced water service disruption, as the pipes can be used around two hours after the lining has been applied. This will speed up the time it takes to return the pipes to service,” Wilson added.
Now that the pilot has been successfully completed, project planning for 2016 is under way. Wilson acknowledges the product has the potential to revolutionize the way Yarra Valley Water carries out its water main renewal program.
In addition, Scotchkote Liner 2400 is garnering a positive reputation in the larger community. On Sept. 10, 2015, at the No-Dig Down Under Awards Evening, 3M and Abergeldie Watertech won the Australasian Society for Trenchless Technology (ASTT), New Technology of the Year Award for Scotchkote Liner 2400.
The ASTT presents the award to recognize a new technology that contributes to the development of trenchless systems and results in benefits such as improved economy, accuracy, speed of drive or replacement, and the ability to overcome difficult installations.
Delivering and maintaining potable water safely, efficiently and with as little disruption as possible is a shared goal across the water infrastructure industry. The best way to do that is ongoing collaboration among technologists, water providers, contractors and communities.
Yarra Valley Water chose a new path with Scotchkote Liner 2400 that’s proven to be efficient and cost-effective and is currently under evaluation for large-scale use.
Sunidh Jani is global business manager – Water Renewal at 3M.