August 2010 Vol. 65 No. 8


Progress Made In Crossbore Avoidance, Discovery

Jeff Griffin, Senior Editor

Crossbores continue to spark concern and controversy among utility providers and contractors engaged in underground utility construction. While no immediate solution to safety issues related to crossbores is in sight, clearly progress is being made.

Efforts of the Cross Bore Safety Association (CBSA) are gathering momentum to educate the industry and the varied organizations and agencies with a stake in eliminating crossbore accidents, and the association’s work is showing results.

On the regulatory front, in May the Minnesota Office of Pipeline Safety issued an alert notice to state pipeline operators setting forth guidelines aimed at eliminating the risk of installing gas lines through sewer service laterals. The action has been described as the first definitive step taken by a regulatory agency to prevent crossbores and verify that none was created at the conclusion of gas line installations. It has been suggested the alert notice should serve as a model for other agencies (for details, see sidebar).

Technically a crossbore is defined as an intersection of two or more underground utilities. However, the major concern is unknowingly boring through a sanitary sewer lateral by horizontal directional drilling or a piercing tool and placing a natural gas line through the sewer pipe.

A crossbored gas line may remain in place for months or years before a blockage develops in the sewer line and the gas line is punctured by a plumber’s power drain auger or “snake” being used to clear the sewer line. The result can be a deadly explosion destroying property and claiming lives. If the crossbore involves a power cable, the operator of the sewer cleaning machine faces serious injury or death from electrocution. Hitting a crossbored communications cable cuts off telephone and internet service.

There are two basic crossbore issues:
• How to prevent crossbores on current and future projects; and
• Developing realistic plans for dealing with “legacy” crossbores (unknown crossbores that have occurred basically since horizontal directional drilling became an accepted method of installing natural gas pipes, roughly since the early 1990s).

A National Transportation Safety Board’s (NTSB) 1976 investigation of an explosion resulting in death was the first crossbore of a gas line in a sewer documented in the U.S., said Mark Bruce, CBSA president. Numerous explosions, injuries and deaths have continued to occur because of crossbores.

Education is the key to finding solutions to prevent crossbores, Bruce believes. The CBSA was formed in 2007 to develop standards and guidelines to minimize the risk of crossbores and to develop and implement training and educational programs toward that goal. Bruce is also president of Can Clay Corp., manufacturer of clay pipe.

“Early efforts of the CBSA were to bring awareness to the potential for damage, injury and death from crossbores,” said Bruce “Although the awareness of crossbores is now fairly widespread, continuing efforts are being made to widen the awareness.”

This year CBSA has conducted numerous presentations at trade shows and industry events.

Several significant events have occurred in 2010. “In April,” said Bruce, “the Minnesota Office of Pipeline Safety invited participation in a meeting of 75 persons that was organized shortly after two explosions occurred in the Minneapolis-St. Paul area. In May, six perspectives of crossbore prevention were given at the 2010 No-Dig Conference. Canadian and U.S. utilities highlighted their programs, contractors discussed solutions and new technologies were presented.

“A CBSA meeting in Chicago in May included consideration of opportunities for improving crossbore safety and education programs. Studies of the cost effectiveness of prevention and elimination of crossbores were discussed at the meeting. Results have shown overall cost reductions when crossbore elimination programs are established by utilities. While safety of industry personnel and the public has and continues to be the main discussion point, damage to sewers has been a growing concern, especially among sewer owners. EPA requirements are driving sewer owners to control any over flows into streams and crossbores affect the integrity of sewers.”

He also noted that CBSA recently has increased efforts to share the ideas about solutions.

“Technically proven methods have been available for the last decade, and equipment is becoming better and more efficient,” he explained. “More importantly, competent practices and processes are becoming more widespread. The danger in having incomplete processes and lack of good records, quality assurance and quality control are more widely recognized. Utilities and contractors are acting by using newer technologies in ways to ensure they fit into a comprehensive process that will eliminate new incidents and address legacy crossbores.”

Bruce observes that awareness of crossbore issues is increasing, and points out that the Minnesota alert and guidelines are not the only recent initiatives that document the change. The Cincinnati Metropolitan Sewer District recently requested bids from inspection companies to inspect for crossbores and determine the condition of their assets. Gas distribution utilities are becoming widely aware of the risks and the risk avoidance practices that are available. Duke Energy is working with the sewer operators to combine efforts to achieve cost effective solutions.

For several years, the Miller Pipeline Corp., Indianapolis, IN, has implemented a program in which Miller crews locate, inspect and mark sewer laterals in areas where construction is scheduled.

Miller President Kevin Miller said “without a doubt” there is greater awareness of crossbore issues than two or three years ago.

“I think,” he said, “many more gas companies, municipalities, plumbers and installation contractors are aware of the situation today for several reasons. First of all, there have been a few unfortunate incidents in the last two years, increasing public awareness of the danger. Secondly, there has been a good push in the industry to ‘get the word out.’ Several of the gas associations have put on educational programs for their members. Some contractors have made presentations to various associations and utility owners. Several industry magazines have helped to keep this issue at the forefront. The Cross Bore Safety Association was established and is actively working to increase awareness.”

Miller said he sees results on job sites.

“In areas where we work, most gas companies, along with their contractors, are taking on the responsibility to prevent crossbores,” he said. “Locating sewer laterals is starting to be recognized as part of the defined scope of work in many contracts.

“A few of our customers have changed their procedures to require post-bore verification that a crossbore didn’t occur. Several companies have expanded their lines of provided services to address crossbore issues.”

People have heard the message and now recognize the risks associated with boring without knowing where the laterals are, he said.

“The industry has gained a lot of knowledge over the last few years, and that should greatly reduce the risk of crossbores going forward.” Miller added.

In the short term, Miller believes utility owners must recognize the risks of installing
facilities without locating sewer laterals and should require lateral locates in their specifications.

“Ultimately,” Miller said, “a solution will require sewer system owners to take responsibility for providing a long-term fix to the crossbore problem.”

IPBA’s Bruce emphasizes that efforts to address crossbores extend beyond utility providers and contractors.

“Manufacturers of equipment,” he said, “can be more responsive to educating those who operate their equipment in specific and detailed ways. This includes new installation machinery and drain cleaning tools. Sewer owners should be aware that providing prints of their systems can be the first step for installers not to damage their lines. The drain cleaning and plumbing industries should be acting aggressively to ensure every worker is educated.”

In conclusion, Bruce observes that the public has a part to play in preventing crossbores.

“The general public can be instrumental in preventing explosions by their awareness of the danger,” he said. “Several utilities and states provide information to homeowners and drain cleaning professionals explaining the potential of explosions resulting from gas lines installed through sewers. These efforts can be expanded. Direct mailings to individual homeowners have been implemented. Education of drain cleaners is logical and effective but not widely adequate. CBSA has participated in education with presentations and manning of booths at trade conventions.”

Cross Bore Safety Association, (812) 719-4800,

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