WorkSafeBC Home

Digging deep to prevent disaster

Published on: November 09, 2020

If B.C. held its own Olympics for underground excavation safety, the City of Victoria would own the podium — especially if the event concerned the elimination of cross bores.

The capital city recently received recognition as the 2013 City of Excellence gold medalist for excavation techniques and underground infrastructure best practices, an honour the city earned in 2011, making it the annual competition’s only two-time champion.

In the process, Victoria arguably became a model municipality for WorkSafeBC’s province-wide cross-boring prevention initiative by recording a perfect score over the past four years. Not a 10, as in the Olympics, but a 0, as in zero cross bores.

“We need to elimate cross bores,” says Gordon Harkness, manager of WorkSafeBC’s risk analysis unit. “Victoria has been ahead of the curve with an active cross-bore mitigation program.”

Harkness says the city stands out for actively ferreting out cross bores, which are the intersection of two underground utilities or structures. They usually occur when a natural gas line gets unintentionally installed through another underground utility, such as a sanitary or storm sewer. Until debris builds up and causes a blockage — or municipalities detect a problem during routine maintenance via closed-circuit TV (CCTV) — cross bores usually go undetected. And that’s why they’re such a danger in B.C.

Municipal crews, contractors, or even plumbers working on private residences, who then flush the sewer line or use a power auger, face a potentially deadly risk from the gas-air mixture. In fact, sources of ignition, such as sparks from electric motors and switches or pilot lights, could ignite the resulting vapour or gas.

“This is a major concern all across the province,” says Cathy Cook, executive director of the BC Municipal Safety Association. “We’ve been contacting our members as much as we can to make sure they’re aware of it.”

Goal to protect workers and the public

Victoria didn’t need the reminder. From 2008 through 2012, its crews had discovered 11 cross bores, says Deryk Lee, the city’s manager of underground utilities operations. None of them caused any damage. But they played a part in the city’s decision to enhance its infrastructure safety program. Like an athlete preparing for the Olympics, the city used technology and specialized training and procedures. “It’s about protecting the safety of workers, and the public,” Lee says.

The city’s underground infrastructure includes approximately 242 km of sewer pipe and 260 km of storm drains, as well as natural gas, hydro, cable, and phone lines. The underground utility information can be viewed on the City’s GIS (Geographic Information Systems) VicMap — a software program accessible to staff and the public — that shows the locations of underground utility installations.

“You can actually open VicMap on your smartphone and look up our infrastructure,” explains Kimberly Meadows, City of Victoria occupational health and safety officer.

The city also created its own training programs, showing crews how to properly read plans. And, it involved all departments, including its parks workers, who sometimes have to cut tree roots underground.

In order to maintain these safe practices, the city developed written operational procedures. Among them was a checklist for pre-job hazard assessment, with a reminder about the threat of cross bores. Workers must fill out the hazard identification checklist prior to any excavation. And, as a means of keeping it top of mind for workers, a daily crew talk record is printed on the back of their time sheets.

The emphasis on safety minimally affected the city’s budget: a lesson Meadows wants to share with other municipalities. “The cost of a hit far outweighs any expenses associated with education, especially since lives could be at stake.”

Cross-bore initiative focuses on cooperation

That philosophy echoes the message WorkSafeBC has been emphasizing since launching its cross-bore initiative in March 2014. The awareness campaign highlights the hidden dangers of cross bores, their abundance — one small municipality has recorded 60 over the years — and their easy, cost-free fix: a quick call to BC One Call. Under the group’s Call Before You Clear program, any reports of suspected cross bores are immediately relayed to FortisBC. In response, FortisBC may then advise by phone that no cross bores are present in the area, or they’ll go directly to the site to provide assistance in safely dealing with them and repairing any damage to pipes.

As part of this initiative, WorkSafeBC has dispatched officers throughout Vancouver Island, the Lower Mainland, and the South Okanagan, where underground infrastructure is generally fairly shallow — a contributing factor to cross bores. (In northern B.C., frozen ground means lines are buried deeper below the surface, greatly reducing the risk of cross bores.)

“I feel pretty confident that our initiative was the best thing to do,” says WorkSafeBC occupational safety officer Doug Fielding. He’s visited 25 municipalities around Greater Vancouver and — with the exception of an “all-clear” at the University of B.C.’s utilities — heard constant reports of the hidden hazards.

Throughout this process, Fielding has been focused on the requirement to develop and implement safe work procedures for drain clearing that will address cross-boring risks. These include provisions for contacting the gas utility company prior to commencing work. So far, he says, working in cooperation with municipalities has been most effective. “Some municipalities are managing quite well. If everyone took these precautions, all of this could go away, with no one injured.”

Harkness points out that FortisBC contractors are no longer practising the directional drilling techniques that resulted in cross-boring, and as a result, no new installations should result in cross bores.

“Everyone is on the same page now,” he says, pointing to the benefit of B.C. municipalities sharing infrastructure information with FortisBC, so they can get help to find and fix the problem.

“WorkSafeBC has accelerated that procedure,” says Ian Turnbull, FortisBC’s damage prevention and emergency services manager. “They’ve really got everyone’s attention.”

And that’s encouraging news for those who would like to see many more employers enter the competition for excellence in excavation safety.

This information originally appeared in the January/February 2015 issue of WorkSafe Magazine. To read more or to subscribe, visit WorkSafe Magazine.