Nonlocatable pipe located with ground-penetrating radar
Problem: For years, a building manager in Germany knew that a water pipe was running into their facility, but had not been able to locate its exact whereabouts. Traditional electromagnetic locators tracked the pipe to a point where it appeared to end abruptly. A valve had reportedly been installed, but none of the locators could detect it. They concluded the original contractor had switched from metal pipe to PVC during the installation. Since EM technology relies on objects being metal to trace them, the PVC section of pipe was not locatable.
Solution: The building manager made one final effort to locate the pipe and valve by calling a ground-penetrating radar expert. The contractor used a Sensors & Software LMX200 GPR system. As operators were surveying the area with GPR, they quickly observed several utilities, each appearing as the classic hyperbolic-shaped GPR response. Data was collected in a zigzag pattern over the buried pipe, and the location of GPR responses were marked on the ground using flags. The path of the pipe was determined by “connecting these dots.” The data showed a plastic pipe response approximately 3 feet deep.
RESULT: The LMX200 was able to successfully locate and map the entire path of the water pipe, both the metallic and PVC sections, right to the buried water valve lid, enabling them to excavate and drain the water pipe. 800-267-6013; www.sensoft.ca
