Plastic pipes led to Hamilton’s natural gas disruptions that displaced customers, closed streets

The same kind of plastic pipe that once was thought to be the water main “of the future” caused Hamilton’s recent natural gas disruptions, mainly on Main Street and Park Avenue, according to a city official.

Water from a deteriorated high-density polyethylene pipe got into a natural gas main that also was made of the same material, leading first to a gas disruption for one customer Thursday evening and then dozens of other outages on Friday. All gas service was restored by 6 a.m. Monday.

The city owns and operates both Hamilton’s gas and water utilities. Such pipes have not been a problem for the gas system, but they are failing with such frequency when used as water mains that Hamilton will be replacing them.

A main factor in the plastic lines failing is the disinfectant, chlorine dioxide, that Hamilton uses to treat its water and keep microbes growing while water flows from the city’s treatment plant to homes and businesses. That chemical process also is what gives the city’s water its award-winning taste, officials said.

Executive Director of Infrastructure Jim Logan in November told Hamilton City Council that Hamilton would be replacing many such water mains this year in the Highland Park neighborhood, at an estimated cost of $3.5 million, with $2.1 million of that coming from an Ohio Public Works Commission with zero-percent interest and the city borrowing the rest.

“We’ve got about 21 miles of (high-density polyethylene) piping in our system now, and it is catastrophically failing, about 60 years ahead of when it should have,” Logan told council in November.

The gas line failure was one situation in which the city’s natural gas lines are at risk the way the water mains are, Logan said Tuesday.

“If it crosses a water main, and then you get essentially our water on it for a sustained period of time, it can embrittle it,” he said.

In the case of last week’s incident, a chemical reaction with the gas main does not seem to have been the cause.

“It doesn’t look like chemical attack in this case; it looks more like a water-pressure type thing,” involving a gas line directly beneath the water main, Logan said.

But as a precaution, the city will be evaluating where water mains cross paths with gas lines in its system, “and start replacing the (plastic piping)in those areas, to stop those from possibly infiltrating our lines again,” he said.

The city put up 22 affected families in the Courtyard by Marriott in Hamilton, including 14 on Friday, and eight on Saturday.

The city still has clean-up work to do on streets in the area, mostly between B and D streets along Park and Main, such as paving parts of the streets when the weather becomes warmer where temporary “cold-patch” asphalt was applied as a temporary fix. Also, the city will be seeding lawns on properties that were dug up.

“All our businesses on Main Street are back open, and thanks for your patience,” Logan said. “We learned a lot from it, and are going to put a lot of measures in place to see if we can prevent the next ones from occurring.”

Crews “worked hard in very difficult conditions,” he said. “They were out there non-stop in restoring service.”

About 36 Hamilton city crews plus another 30 contractors worked on repairs, with city administrators, customer-service people and others working extra duty.

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