10 June 2015

Failure triggers investigation

Palmerston North City Council staff were surprised at the failure of eight metres of sewer pipeline in Maxwells Line and are now preparing unscheduled internal inspections for a number of the City’s pipelines where corrosion risks are highest.

“That section of 825mm diameter concrete pipeline is only 15 years old,” Rob Green water and waste services manager said. “The concrete that is used to make the pipes is especially thick and was specifically treated to prevent corrosion which can occur from the hydrogen sulphide gas that is released in parts of the network. It has a life expectancy of between 50 and 100 years.”

The collapsed portion of the pipe has occurred in the traffic lane just south of the intersection with Carter Crescent and Maxwells Line.

“We have replaced the section of pipe,” Rob said. “There has been no interruption to the sewage flows and no risk of contamination to surrounding properties from sewage.”

“Pipes of this size are very costly, they can cost up to $1,000 a metre to install,” says Rob, “and because this pipeline was relatively new there are no provisions in the budget for it.”

Rob Green says staff will investigate adjacent lengths of pipeline to the area that failed, carrying out checks to determine if more sections are at risk.

“I’d also like to thank motorists and nearby residents in the Maxwell Line area for their patience,” Rob said.

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