Beware the maze of underground utilities
Published Saturday, February 23, 2013 4:00PM EST
Last Updated Saturday, February 23, 2013 11:05PM EST
Many North American homes sit peacefully above a cat’s cradle of pipelines and wires, culverts and cables. Long buried. Long forgotten. Forgotten, that is until a backhoe hooks a sewer pipe or a plumber pierces a gas line and then the unthinkable happens: a spark; a fire; an explosion -- and that peaceful neighbourhood is consumed in a catastrophe of flame and smoke and death. Three years ago, Trista Meehan was lucky to escape just such a home explosion with her life.
It all began when Trista noticed a problem in her basement. She had recently bought her “dream home” in a quiet neighbourhood of St. Paul, Minnesota but after moving in noticed that her sewer had backed-up. Trista, never one to shy away from a dirty job, rented a plumber’s snake and rolled up her sleeves. For hours she twisted and turned, pushed and pulled but no matter how hard Trista tried she simply could not clear the blockage.
The next step? She called a professional plumber who brought in a power-driven snake with a razor-sharp cutting bit. The problem however was that the blockage was not a normal accumulation of household debris. Rather, Trista’s sewer pipe had been a natural gas line running through it and when the plumber’s snake sliced through the fragile PVC of the gas pipe, a flash fire and then an explosion ensued. The plumber was badly burned and Trista barely escaped with her life. Her home and all her belongings were lost.
“It felt like the house had been bombed”, she recalled, in an interview with W5’s Tom Kennedy. “(The plumber)…came running up the stairs telling me to get out! Everything was on fire. It was an inferno.”
Trista’s near-deadly problem was that the gas line had been inadvertently installed through her existing sewer line. Industry professionals, such as Professor Mark Knight at the University of Waterloo, call this situation a cross-bore. Knight has been studying cross-bores for years and notes that with the advent of “trenchless technology” and the rapid growth of utility and telecommunications below-the-ground installations – ‘out of sight, out of mind’ is a dangerous assumption for home owners to make.
No one knows how many cross bores exist in Canada and the USA. But an American estimate suggests that in older neighborhoods where consumers have recently converted to gas, there could be as many as two cross bores per kilometer. Canada’s gas companies encourage Canadians to always “Call Before You Clear.” If your sewer is blocked, call the gas company before sending a snake down.
But the problem is one of both casual engineering and careless human behaviour. Messages often don’t register with people unless they are accompanied by tragedy. So far, Canadians appear to have been lucky.