Programs Grow To Eliminate Crossbores

By Jeff Griffin, Senior Editor | April 2013, Vol. 68 No. 4
Greg Scoby, P.E.

"Progress in Efforts to Eliminate Crossbores" was the topic of one of the presentations in the Damage Prevention and Safety track at the 2013 Underground Construction Technology International Conference & Exhibition.

Crossbores -- inadvertent installations of gas or power cable through a sewer lateral -- are an ongoing concern of utility providers and contractors.

In this session, Greg Scoby, P.E., vice president of Frontline Energy Services, described a proactive, highly successful program used by the city of Palo Alta, CA. to identify gas lines that have penetrated sewer laterals during installation by horizontal directional drilling (HDD) and to correct the problems before a costly and dangerous accident can occur. Scoby previously was engineering manager for Palo Alto’s city-operated utilities.

A separate city program requires closed-circuit television (CCTV) inspection of a lateral any time an HDD installation has been made nearby to confirm no crossbore has occurred.

Scoby made clear that Palo Alto’s program to identify crossbores was facilitated by the fact that the city owns gas, sewer, water and electric utilities, a situation not found in most U.S. cities.

Even so, Scoby said he believes similar programs can be effectively implemented when multi-service providers are involved and Frontline Energy is actively assisting clients with crossbore elimination programs. The Palo Alta program has generated interest among other cities and Scoby has been busy answering questions, making presentations and meeting with representatives of cities and gas service providers.

“I usually start by meeting with the local gas operator and gauging their program to address the crossbore issue,” Scoby said. “With cooperation of the various parties involved, the crossbore problem can be turned into a win-win situation.”

Trenchless risk

Citing the Palo Alta program, Scoby said crossbores found during inspections were associated with trenchless construction methods utilized to install gas systems.

“If the local gas operator has not used these trenchless construction methods, risks of crossbores could be minimal,” he continued. “If gas lines have been installed by trenchless methods, it could be possible for the local utility agency to work with the gas operator to conduct system assessments and address crossbores that are identified.”

Such programs address legacy crossbores. A related but separate issue is preventing future crossbores.