Quebec natural gas consumers have been granted a reprieve from losing heating season supplies as a result of a potential hazard on their lone pipeline.

The National Energy Board (NEB) granted Trans Quebec & Maritimes Pipeline (TQM) permission to restore full operating pressure for eight months. The action followed appeals by French Canada’s distributor, Gaz Metro Inc. (GMI), and TQM owner TransCanada Corp. for the NEB to lift a Sept. 8 safety order for a 10% pressure cut (see Daily GPI, Oct. 17).

Since Quebec has no other supply lines and no gas production of its own, GMI warned that the order confronted about 180,000 customers with chilling prospects of losing fuel during periods of peak cold weather needs.

In a letter granting the reprieve, the NEB agreed with GMI and TransCanada that the hazard that prompted the order “is not an immediate threat.” But the board added that the problem, a form of metal fatigue known as stress corrosion cracking (SCC) “may become a future threat if not found and remediated.”

As operator of TQM, TransCanada was given an amended order to use the eight-month reprieve for detecting and repairing SCC sore spots.

The order followed a disclosure to the NEB by TransCanada that an inspection program using remote sensing devices found nine “anomalies” that could be SCC along TQM. The presence of the hazard can only be confirmed — and repairs can only be made — by digging up the suspect lengths of pipe.

TransCanada had postponed the field work while NEB engineers conducted a parallel review of TQM’s construction standards to ensure that the line complies with heightened safety requirements for pipelines in areas of population growth and expanding real estate development.

At sites where the engineering requires standards to be raised, the NEB ordered TQM to conduct monthly surveillance, install above-ground warning markers, conduct frequent leak detection inspections and complete improvements by June 30, 2012.

SCC has been systematically hunted down and repaired on Canadian pipelines since 1996, when an NEB inquiry found that the hazard caused a rash of 22 accidents including a dozen ruptures and 10 leaks over the preceding few years.

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