December 1, 2008

FILE PHOTO

This excavator struck a natural gas line at a Vancouver worksite earlier this year.

BC Common Ground Alliance

Safety officer calls tangled web of buried utilities a ‘ticking time bomb’

Richard Gilbert

staff writer

Contractors must wade through a sea of phone numbers and organizations to find all the underground utilities on any given jobsite.

Buried utilities, especially natural gas lines, can pose a serious danger if struck.

“We have had very few catastrophic hits, but it’s only a matter of time,” said WorkSafeBC occupational safety officer Mark Valastin.

“It’s a ticking time bomb.”

He was speaking at a conference in Vancouver hosted by BC One Call and the BC Common Ground Alliance about safe digging practices.

“The regulations say that before you dig you must expose and identify underground utilities,” Valastin explained.

“You must do your due diligence and identify all underground utilities before you dig.”

This means the contractor has a legal obligation to use existing plans or drawings to physically identify where utilities are located.

The lines must be exposed by hand to determine the direction they are going.

To do this, a contractor is supposed to phone BC One Call, so they can find out what is buried on their dig site.

Problems can arise when the information on a drawing does not correspond with what is happening on the ground.

“If you notice a discrepancy on the plan, you can call the utility and they will come out and show you the line,” explained Valastin.

However, other problems can arise because other utilities may not be part of the BC One Call system.

“Not all utilities are members of BC One Call,” explained Andrew Mark, general manager with One Call Locators Canada Ltd., a private company not affiliated with BC One Call.

His company attempts to fill the gap between the information provided by BC One Call and finding out where all the utility lines might be.

It can get rather confusing.

“You need to know who to contact depending on your work area and municipality,” he said.

For example, Metro Vancouver, Shaw Cable and the City of Vancouver are not members of BC One Call.

One Call Locators gather information about the various buried utilities and sends a utility locator to a jobsite.

The locator finds line by electromagnetic detection, which identifies oil, gas, electric, communications, water and house services.

The company also uses ground penetrating radar to find non conductive utilities, such as PVC, plastic water and sewer services and concrete.

The company marks the lines on the surface, so the contractor can hand expose the lines and continue excavating.

The recent construction boom has compounded the problem.

“There was rise in gas line hits between 2006 and 2007, which can be attributed to an increase in construction activity, due to a busy economy,” said Michael Chisholm, communications manager at Terasen Gas.

He maintained that the cause of many incidents has not changed.

Some contractors simply don’t make a call to BC One Call for gas line information before digging.

Alberta is in a similar situation.

ATCO Gas reported a similar jump in the number of gas lines struck in the province so far this year.

More than 1,000 natural gas lines were ruptured or severed during digging in Alberta last year and that number is up again. In both provinces, those responsible for the damage are also responsible for the repair bill.

GAS LINE HITS
In B.C.
2007: 1,750
2006: 1,560
2006 repair cost: $1 million
Reasons behind 2006 hits:
Didn’t obtain location: 74%
Unsafe excavation: 16%

July 2008
Hits in Metro Vancouver: 38
Reasons behind July hits:
No BC One Call ticket: 82%
Car accidents, fires, storms or mud slides: 9%
Misinterpreted location info: 1%

In Alberta
Total hits for 2007: 1,000+
2008 January to mid-October
Calgary: 142
2007 total: 153
Edmonton: 90
2007 total: 109

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