Replacing AC Pipe Via HDD, PVC

September 2012, Vol. 67 No. 9

For this project, Wiseman Utilities purchased a special tool from CertainTeed for fabricating spline grooves and beveling pipe on-site. They also purchased an assembly tool from Pro-Pipe Solutions called the Eagle Claw. This helped the pipe assembly to run even more smoothly, as it helped the crew to pull the collars in more evenly and line up the pipe string correctly. The biggest challenge of the project came after the pipe was installed, when the crew disconnected the existing lateral mains from the existing eight-inch AC main and reconnected them to the new main at street intersections.

“Doing the interties with the existing water mains in the intersection was challenging because the existing mains had been placed at all elevations and at different times of history,” Wiseman says. “As for pipe, it was a mixed bag of materials, from steel and ductile iron to AC and PVC. This made the process more labor-intensive. The crossover work was done at night to minimize service disruptions to the affected businesses. We learned after the first crossover to do them on Thursdays so the crew could have the whole weekend to rest up.”

Speedy completion

As the project moved into winter, the crew also ran into some days of snowy and icy weather, which occasionally stalled the project. The contractor still met its deadline, though, finishing in 45 work days, and the new water main easily passed pressure testing. After it was brought online, the old AC water main was plugged with control density fill and abandoned, per the regulations of the State of Washington Department of Ecology.

Wiseman Utilities received excellent feedback for its work and for keeping disruptions at a minimum.

“It went very well,” Wiseman says. The city and business owners along the project route were very pleased. We only had to close the far right lane of a four-lane boulevard, so the disruption was minimal.”

In addition to HDD helping the project run more smoothly and keep down disturbance, it considerably decreased project costs by minimizing the need for road restoration. The city of Olympia was very pleased with all of these results.