April 2017 Vol. 72 No. 4
Features
Fort Worth, Atmos Team-Up For Crossbore Prevention
The city of Fort Worth, TX, and Atmos Energy, the area’s gas service provider, are taking a proactive approach to address possible crossbores in the city’s sanitary sewer pipes.
Crossbores – an intersection of two or more underground utilities – is an ongoing concern of municipalities across the country, and those with the highest potential of causing damage and injury are gas lines installed through sewer pipes. Typically, a crossbore occurs during a horizontal directional drilling (HDD) installation of a utility line, which accidentally crossbores through another utility’s line without being noticed by the installer. This aberration is what the Fort Worth-Atmos Energy program seeks to address.
A gas line crossbore through a sewer line can be in place for years without being discovered. If a natural gas line is cut or nicked while unclogging a sewer line, it can create a serious hazard. Damaging a natural gas line can cause a fire or explosion and lead to even more serious damage or injury to those working on the sewer line and people nearby.
Under a Memorandum of Understanding (MOU) between Fort Worth and Atmos executed in March 2016, Atmos Energy is inspecting city sewer lines to locate crossbores that may have occurred. If found, Atmos Energy relocates the crossing gas line and utilizes city-approved contractors to repair the sewer line.
To date, approximately 20 miles of pipe have been inspected, and 37 crossbores confirmed.
“Atmos Energy,” said John Carman, director, water department for the city of Fort Worth, “should be applauded for being proactive and taking responsibility for reducing the potential gas line crossbores.”
Active program in place
At the present time, Atmos inspects new construction in areas where potential crossbores could occur. Carman said a process has been established.
Atmos inspections are conducted Monday through Friday, except holidays. Prior to an inspection, Atmos requests a work permit. Once all the necessary maps and information are provided, the city reviews and approves the permit. Atmos then must clean a sewer main from manhole to manhole, per water department specifications for sewer cleaning and televising process, and utilizing the city’s GIS identification numbers and a city-approved contractor.
The pipe is cleaned, inspected and documented by closed circuit television (CCTV) using a combination of vacuum trucks and CCTV trucks. Pipe diameters inspected vary.
If a sewer crossbore is located and it is a natural gas line, then Atmos Energy will notify the city, and utilize an approved, pre-qualified city contractor to repair the damaged sewer or storm pipeline per city standard specifications after the initial crossing gas utility has been suitably relocated. Once repairs are completed, the city will inspect the repairs before the excavation is restored.
If the crossbore is not a natural gas line, the city will be notified. Atmos Energy is not responsible for repairs or other damage costs associated with any crossbore caused by other utilities.
Atmos Energy provides notice to the city water department 10 business days prior to beginning work and does not begin without approval of the city.
During repairs, Atmos Energy is solely responsible for any and all sanitary sewer overflows, backups, stoppages and procedures that occur as a result of its work under the MOU. Atmos Energy immediately notifies the city of any such event and copies the city on all communication with the Texas Commission on Environmental Quality (TCEQ). Atmos is responsible for reporting, responding and paying any and all fines or judgments assessed by the TCEQ due to the work performed under the MOU, to the extent any fines or judgments are the result of Atmos Energy’s negligence or willful misconduct.
Bonus information
The city requires video inspection files for all sanitary sewer lines and stormwater mains. Atmos Energy provides the CCTV data to the Water Department’s Field Operations Division, where it is reviewed. A dedicated staff works more than 30 hours per week with the inspection videos. City personnel communicate with Atmos regarding the videos as necessary. Their usefulness is not limited to crossbores.
“The videos help the city find other defects (grease, root, debris, etc.),” said Carman. “Any crossbore can create a backup.”
It’s definitely a team effort.
“The city of Fort Worth realizes the health risks – asphyxiation and explosions – to our customers if a gas leak fills a sewer line or enters a home via a sewer line or pea trap,” said Carman “We always are concerned about the safety of the public and our employees. We want to be proactive instead of reactive, and to find hidden utilities before they become dangerous, and we want to avoid costly repairs.
“The city of Fort Worth/Atmos Energy Cross Bore Program helps to achieve these goals.”
Fort Worth and Atmos Energy work closely together to identify accidental damage to utilities if a gas line is inadvertently crossbored or inserted through the sewer line when installing gas mains and service lines.
“This collaboration allows Atmos Energy, as well as the city, to review inline camera inspections on sewer mains and laterals,” said Gary Thigpen, director of operations, Atmos Energy Mid-Tex division. “We appreciate the city’s willingness to allow our contractors to perform inline inspections as we work to improve our underground facilities while making our safe and reliable gas system even safer.”
Thigpen said Atmos Energy actively promotes the toll-free 811 call-before-you dig number and makes plumbers aware of the risks of a potential crossbore when cleaning a sewer line. The message includes: “Before using any mechanical or cutting equipment, Atmos Energy recommends using a video camera to inspect the inside of a sewer line to rule out a crossbore with a natural gas line or other utility line. If your company does not have a video camera and you suspect a cross bore situation, please call Atmos Energy at 866-322-8667.”
The Fort Worth Water Department is responsible for providing safe and reliable water and wastewater service with environmental integrity. Fort Worth has a total treatment capacity of 497 million gallons per day for drinking water and 166 million gallons per day for wastewater; with five water treatment plants and one reclamation facility. There are more than 3,336 miles of pipe in the water distribution system and 3,266 miles in the collection system.
The system serves more than 1.2 million people in Fort Worth and surrounding areas, which includes 30 wholesale water customers, 23 wholesale wastewater customers, and three wholesale reclaimed water customers.
Atmos Energy Corporation, headquartered in Dallas, is the country’s largest, fully-regulated, natural-gas-only distributor, serving more than 3 million customers in over 1,400 communities in eight states, from the Blue Ridge Mountains in the east to the Rocky Mountains in the west. Atmos Energy also manages company-owned natural gas pipeline and storage assets, including one of the largest intrastate natural gas pipeline systems in Texas.
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