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Programs Grow To Eliminate Crossbores
Scoby believes both efforts are being facilitated by the Distribution Integrity Management Programs (DIMP) program adopted by Pipeline and Hazardous Materials Safety Administration (PHMSA) in 2011 which requires gas operators to categorize and evaluate risks associated with their systems.
Multiple efforts are needed to prevent crossbores from occurring. Scoby said such efforts include establishing working relationships among local governments, sewer agencies and gas providers, specify a data collection system, identify locations for inspection, preparing a pilot program identifying risks and modify construction practices to minimize the risk of future cross bores. An important element in the success of such efforts is a public awareness campaign directed to customers, plumbers, draining cleaners and rental companies to call the local gas provider before attempting to clear drain blockages.
“I believe the adoption of DIMP will increase crossbore investigations for gas operators who have employed trenchless construction methods in the past,” Scoby said. “Hopefully, wastewater collection system operators will partner with their local gas company and work to facilitate these inspections to the benefit of all involved parties.”
Regarding construction procedures, Scoby emphasizes that proactive pre-locating is a stop in preventing crossbores and damage to all utilities.
During construction, the one certain way to determine a lateral or any utility’s precise location is to uncover and visibly identify it. Being uncovered also allows crew members to verify and the HDD drill bit has not hit or penetrated the pipe.
“Locating by potholing can be costly and involved parties often don’t want to pay,” Scoby said.
“It’s a balancing act,” he continued. “Not verifying locations increases risks of crossbores. Ultimately, there has to be a change in mindset -- that a new gas line won’t be energized until it’s known to be ‘clean’.”
While coordinating legacy crossbore programs and modifying construction methods is a complex undertaking, Scoby said progress is being made.
“In addition to Palo Alto, Duke Energy requires 100 percent post-construction video inspection prior to introducing gas to newly constructed lines,” he said. “Southwest Gas, Excel Energy, Southern California Gas and Pacific Gas & Electric all have SLIP (sewer line inspection programs.”