Pipe Inspections Target Sewer Cross Bores in Minnesota

In February 2010, a St. Paul, Minn.-home exploded as a plumber was snaking out a clogged sewer lateral.
The reason? A gas line had been bored through the sewer lateral years before.

“The gas backed up in the home and ignited,” says Bill Kaphing, vice president of Control Center for Xcel Energy, the utility supplying gas through the pipeline. Fortunately, there were no serious injuries, although a lawsuit is pending from the homeowner.

In the aftermath of the incident Xcel Energy has embarked on a massive inspection of gas and sewer lines to inspect for other gas line-sewer line cross bores “to see how big of a problem this is,” Kaphing says.
For KS Energy Services, one of the contractors Xcel has hired for the project, the Lateral Evaluation Television System (known as LETS) from Aries Industries Inc. is a key project tool.

Like the old advertising slogan about a breath mint, the Aries LETS is two cameras in one, enabling simultaneous inspection of mainline and lateral applications.

The more traditional mainline inspection is accomplished with an Aries self-leveling straight view camera that provides a full view of the sewer line. Improved LED lighting technologies help to transmit highly illuminated images to televising and recording devices.

The second ‘push’ camera inspects lateral lines up to 150 ft in length and as small as 3 in. in diameter. This Aries camera is mounted at the end of a rigid, patented fiberglass-core cable that enables a fast and efficient camera launch. Users have choices between mini-camera options, whether they prefer self-leveling or pan-and-tilt.

Aries new PE3600 mini pan-and-tilt design is becoming the more widely preferred option offering a unique combination of features. The PE3600 can rotate beyond 360 degrees, bringing the lens through a set of wiper blades that clean debris off the lens surface. End users no longer need to retrieve, clean and re-launch the camera each time the lens becomes dirty. The self-cleaning innovation enables users to return to productive inspections seconds after cleaning.

The LETS design has boosted productivity and convenience on the job, says Grant Klumb, project manager for KS Energy Services. The contractor is based in New Berlin, Wis., a suburb of Milwaukee.

No longer does the contractor have to get access to each home in order to inspect the lateral from the house outward, Klumb explains. Instead, the camera unit simply travels down the main and the second “push” camera launches into the lateral line, inspecting up to 80 ft from the water main.

“Without the Aries LETS system, we would have to go into each house,” says Klumb. “It would be a logistical nightmare.”

For the Xcel project, that’s especially important. Over the next two years, the cross bore inspection program will target 40,000 locations in the Minneapolis/St. Paul metro area in search of potentially hazardous gas line cross bores through sewer laterals. This is about 10 percent of the utility’s 430,000 customers.

“We focused on those areas where we have had incidents in the past and expanded our camera inspection along those projects,” Kaphing explains. The inspection is especially zeroing in on public buildings — schools, churches and hospitals, for example — for the camera work.

“We’ll take the results that we find from these initial inspections to find what the next step of our project should be,” he says.

For Xcel, the biggest challenge in the project would have been for its contractors to schedule appointments with so many customers, according to Dave Madigan, project manager for the inspection program.

And while Xcel Energy didn’t pick the Aries LETS technology that KS Energy Services elected to use in its inspections, the company has clearly benefited from the choice.

“Going through the mainline is more efficient for us,” says Kaphing. “We don’t have to disturb the customer at all. It’s a time saver.”

Using more conventional push cameras, sent into each lateral from inside the customer’s home or business, Klumb says he could only expect to look at no more than 10 to 15 lines per day. With the flexibility afforded by the Aries LETS, that number has skyrocketed: crews have been known to record inspections at more than 40 lateral sites in a single day.

Klumb, whose firm is using the LETS model LE2165 for the job, says he’s been especially impressed by the quality of images delivered by the Aries lateral camera, as well as its maneuverability. The 80-ft cable for the lateral camera is more than enough length to inspect in typical older neighborhoods in St. Paul where KS Energy Services has been working, as laterals are approximately 60 ft in length.

In some areas, where laterals extend as much as 200 ft from the main line,  Klumb opts for the portable Aries Seeker push camera.

Besides the productivity of the LETS, Klumb has also found it to be remarkably durable as the machine is put through its paces in the underground lines.

“We’re pounding it non-stop,” he says. “They’re still handling what we’re doing.”

Jeff Thorpe is senior product manager for Aries Industries.

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