Detector Dog Services International was called to the Beaverlodge area in Alberta to provide leak detection services on a 2.2 kilometre 4 inch fibreglass natural gas pipeline. We were informed that the pipe was no deeper than four feet and that the leak was very small. A normal DDSI requirement to aid the dog in locating any leak is that the pipeline be boosted to its manufactured maximum PSI so that the odourant reaches the surface with sufficient aroma to allow the dog to locate the leak in optimal time. In this case, the line could only be pressurized to 350psi — much lower than our recommended pressure. To compensate, we arranged for the line to stay pressurized an extra day.
The pipeline was searched six times with the dog over a two day period. That's an unusual amount of activity, but there's a reason it took that long. Normally when our dogs locate the odour they will dig at a specific location. At this site, which was near the battery, the dog did not dig but instead continued searching over a large area. He repeated this behaviour each time we approached the battery. By the fourth attempt on the second day there appeared to be very little odour rising to the surface, and the fact that the pipe pressure was decreasing more slowly indicated the leak was actually resealing itself.
DDSI then recommended the client dig near the battery at a point that seemed of most interest to the dog. The vac truck began removing soil and, even though the pipeline was only supposed to be four feet underground, it continued removing soil well past the nine foot mark. At the ten foot mark, a steel pipeline, not a fibreglass line, was located, further increasing the mystery. Apparently the steel line was actually a casing with the fibreglass line inside due to its position under a roadway. Further digging revealed that the leak was inside the casing. As a result, the odour was coming out the end of the casing and, due to the low PSI, had been slowly drifting upward to the surface over a large area, from which it was being carried by the wind.
This was a very confusing situation for the dog, but as difficult as it was, the dog still found the leak! Although the search was conducted over two days to make sure there were no other leaks, the initial indications from the dog came within the first twenty minutes of the search, which is our normal experience.
The alternative to using a dog would have involved a system of digging, cutting, capping and pressurizing, section by section, until the leak was found. At a cost of approximately six to ten thousand dollars per dig location, in this particular case that system could have cost the service company up to sixty thousand dollars. DDSI's charge was a fraction of that, saving the company tens of thousands of dollars.
DDSI was contacted to find a leak on a new 4 inch line in the Spruce View, Alberta area. The line was 2.5 kilometres long and had already been cut and pressurized at a cost of just over ten thousand dollars. The leak was located within the first five minutes of the search, saving the client tens of thousands of dollars in additional costs.
Near Tumbler Ridge, BC, a 16 inch pipeline over 90 kilometres long appeared to be leaking. DDSI had the line pressurized to 1800psi and began searching for leaks. The line was laid out in nine 10 kilometre lengths over steep terrain, with some locations accessible only by helicopter. The entire line was searched over a ten day period and no leaks were discovered on the lines themselves. However, at one location, where a 6 foot riser was situated, the dog started to jump in the air, trying to reach the top, and then just sat facing the riser. The odourant appeared to be coming out of the pancake, or top of the riser.
The leak was reported to the client but the report was received with a great deal of skepticism because the pressure monitoring instruments were indicating full pressure at that location. DDSI then took the dog, along with the client, back to the riser and together we observed the dog's behaviour. The client was then advised to walk to the area by the riser, and upon doing so he was able to detect the odourant. The client was completely amazed that the dog could find a leak which the measuring instruments insisted did not exist!