Rainbow to conduct pilot project test for cured-in-place lining

The Rainbow Municipal Water District will be conducting a test of cured-in-place lining for water transmission pipe.

A 4-0 Rainbow board vote Oct. 27, with Helene Brazier not able to participate in the meeting, approved the professional services agreement with Sanexen Water, Inc., for $74,800 and appropriated that amount from the water capital fund for the project's budget.

"This is a pilot project," said Rainbow General Manager Tom Kennedy.

"We think this one has a really great potential," Kennedy said. "We can test and validate that the system works."

Corrosion and pipeline pressure are significant factors in pipeline failures. Rainbow has a cathodic protection program to address external pipeline corrosion and has also been installing pressure-regulating stations to address system pressures. Neither the cathodic protection program nor the installation of pressure-regulating stations address corrosion which occurs on the inside of the pipelines. Much of that interior corrosion occurs at uncoated joints.

"This is something that I have passionately tried to find a solution to for about 20 years," Kennedy said.

"The mortar is porous so the water pressure will seep through that," Kennedy said. "If you seal that gap it's just going to cause a leak."

Sanexen is headquartered in Quebec and has a western office in northern British Columbia. Rainbow staff and Sanexen have been trying to coordinate a pilot project to determine the effectiveness of Sanexen's Aqua Pipe potable water lining technology and associated procedures on Rainbow's concrete mortar lined and coated steel pipe infrastructure.

"That seals a liner to the steel in that area," Kennedy said.

The Aqua Pipe liner is a cured-in-place pipe which is designed specifically for deteriorated pressure pipe conditions. The system installs a new liner inside the pipeline, which eliminates the internal corrosion, without the need to replace pipelines or disturb streets.

"We can replace that pipe without having to dig it up," Kennedy said.

The existing pipeline replacement method involves excavating the entire alignment, installing the new pipeline, and backfilling the entire excavated area.

"If we can not have to dig it up, it's going to be a big game-changer for us," Kennedy said. "We expect it to be less expensive and less disruptive."

The cost to replace a pipe includes traffic control and utility coordination as well as the labor and materials. "A lot of what we're looking at here is mobilization," Kennedy said of the expenses.

The benefits will be enhanced on busy streets and in environmentally sensitive areas. The cured-in-place pipeline requires minimal excavation, primarily one at each end of the pipeline being rehabilitated.

"I think this has the greatest potential for us to do lining," Kennedy said.

There is a CML&C pipe six inches in diameter in the lower dirt yard of Rainbow's property. The pilot project would line approximately 300 linear feet of that. The 300-foot section includes two one-inch and one two-inch service connections, and after the lining is completed Sanexen will re-establish the service connections using robotic tools inside the pipeline.

"We want to see how it's done," Kennedy said.

Sanexen will also line 40 feet of above-ground pipe six inches in diameter with two one-inch and one two-inch service connections. "We can inspect it, do some additional testing on it," Kennedy said.

The estimated lifespan of the lining is 50 years.

"I don't think it's going to be a panacea for every situation," Kennedy said. "There are places where it's not going to be applicable."

The duration of the Sanexen work will be approximately five days.

"We're looking forward to this," Kennedy said. "We're pretty excited to get going on it."