Trenchless Water Main Rehabilitation In Pasco, WA

July 2012, Vol. 67, No. 7
Installation of NordiPipe with pressure vessel.

Together with its licensee, Michels Pipe Services, Sekisui NordiTube, Inc. solved a recurring water main problem for the city of Pasco, WA, with its water main rehabilitation solution NordiPipe. The leaking 12-inch water pipe was located under an active railway intersection in the southeast side of the Pasco. The deteriorated existing pipe was successfully rehabilitated increasing the functionality of Pasco`s water supply system.

In 2011, Pasco was needing to find a long-term solution for two sections of a deteriorated12-inch, lead joint, ductile iron pipe that runs eight feet under six sets of Burlington-Northern railroad tracks. Around five years ago, Pasco chose to temporarily reroute the water supply because open-cut construction was out of the question. Due to the continual traffic and the importance of the switching yard on the southeast side of Pasco as a major intersection of railways on the west coast, shutting down the railways to repair the leaking pipe was not possible. Equally as important, three of the rails immediately cross the Columbia River on one of the few bridges providing access to the south. Michels Pipe Services, a Sekisui NordiTube licensee, was instructed to rehabilitate the 1945 installed pipe by the trenchless pipe rehabilitation technology NordiPipe.

Michels started the installation of the NSF 61 approved NordiPipe liner in October 2011. The liner was prepared in Michels’ Salem facility and transported to the site overnight, reducing the time between activating the epoxy resin and the actual pipe installation. This was different than most epoxy methods that require on-site resin preparation. Additionally, costs could be reduced by preparing the liner in Salem as opposed to assembling an on-site wet-out area.

What took years of rerouting the water main supply for Pasco, Michels was able to repair in just two days. Michels tackled the project in two separate 275-foot sections. Using a pressure vessel to invert the tube and curing it with steam to a statically self-supporting pipe within a pipe meeting AWWA Class IV standards, each installation took 12 hours. End seals were used to join the NordiPipe liner to the existing ductile iron pipe and after a 150 psi pressure test, the pipe was returned to service.

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Installation of NordiPipe liner under six sets of Burlington-Northern railroad tracks.

“The project went as planned in spite of some changing conditions. Michels, the city of Pasco and NordiTube made adjustments on the project to compensate and complete the job,” according to Chris Tavernier, Michel’s onsite supervisor.