Loud noises have been heard this week at a section of TransCanada pipeline near Ile des Chenes.

Doris Kaufmann Woodcock is Senior Communications Advisor for TransCanada. She says they are performing routine maintenance. In order to prepare for this, natural gas in that section of pipeline must first be safely released. As a result, Kaufmann Woodcock says people in the immediate area might hear a loud noise referred to as a blowdown.

"This noise occurs when the natural gas which is compressed into the pipe at very high pressure escapes through the opening valve, which makes a very loud roaring sound as it rushes out," she explains.

Kaufmann Woodcock says this is similar to the noise of air being released from a car tire, only much louder. Once the valve is open, some of the natural gas will dissipate into the air and a portion will be drawn out by special machinery that will redirect any of the remaining natural gas into another section of the pipeline. This then makes it absolutely safe for workers to do maintenance activities, such as welding.

By Tuesday afternoon, some of the preliminary work had already started. Kaufmann Woodcock says the work will continue until the end of Thursday. She notes once the maintenance work is complete, crews will need to do a similar process which is to blow the air out that had been built up in the pipeline before putting natural gas back in and re-pressurizing the whole system.

Kaufmann Woodcock says TransCanada realizes the noise and the work can be an inconvenience for neighbours. The goal is to minimize the effects which means no work during the night.

According to Kaufmann Woodcock, there will be nothing visible to see while the loud noises are being heard. And she says the natural gas in long haul transmission pipelines, such as this, is rarely odorized. There should be no disruption to service for customers during this time.

She notes the maintenance is being done to ensure a steady and reliable supply and also for safety purposes.