Pacific Gas and Electric Company (PG&E) announced that it has added a new, high-tech laser scanner device to its suite of technology used to enhance gas pipeline safety in the field. This new tool provides a highly efficient and accurate way to determine the safety and integrity of natural gas pipelines.
The hand-held device, called EXAscan, manufactured by Creaform of Levis, Quebec, is held a few inches above a section of pipeline and produces a three-dimensional, color-coded view of the pipeline on a monitor. Accurate within 40 microns, or 0.0016 of an inch, the device can detect potential safety concerns such as corrosion, dents or warping within a pipeline.
Conventional industry practice for measuring pipeline corrosion involves digging down to a section of the pipe, drawing an extensive grid of one-inch squares on the pipe, and then measuring the "wall loss"—or effects of corrosion—square by square with a manual tool. The EXAscan technology allows PG&E to capture the same information from the entire pipeline section within minutes and helps assess whether that section is fit for service. PG&E Senior Welding Engineer Bronson Shelly described using the new product as "night and day" compared to the manual process.
"When it comes to finding the nooks and crannies of pipeline dents or external corrosion, the EXAscan provides speed and detail far and above the mechanical way of doing things," said Alex Gutierrez, a supervisor with PG&E's Applied Technology Services division.
The device has already proven useful at PG&E. In spring 2012, a crew in the East Bay used it to check the status of a gas pipeline when the weight of a construction crane caused an underground water main to break. The crew did an ovality check—a process that ensures the pipeline is at least 97 percent of being perfectly round—on a nearby gas pipeline to confirm that it did not sustain damage. In that case, the scanner found no concerns with the pipeline's shape, thereby assuring its integrity.
The EXAscan's capabilities extend beyond gas operations into PG&E's electric operations and electric supply. The device helped PG&E's hydroelectric engineers perform a stress test to ensure the structural integrity of newly repaired rotors at Helms Pumped Storage Plant in the Sierra National Forest.
The EXAscan technology will work in conjunction with other pipeline safety tools to help PG&E test, repair and replace segments of pipeline as needed throughout PG&E's service area, as set forth in PG&E's Pipeline Safety Enhancement Plan (PSEP).