FERC has approved Southern Natural Gas Co. LLC’s (SNG) request to abandon nearly 20 miles of pipeline and associated facilities in Alabama to comply with a correction action order issued by the Pipeline and Hazardous Materials Safety Administration (PHMSA) to address the hazards associated with wrinkle bends, which led to a failure on SNG’s system in late 2009.
SNG, which was recently acquired by Houston-based Kinder Morgan Inc., plans to abandon in place 19.56 miles of its North Main Loop Line from the DeArmanville Compressor Station to the Rome-Calhoun Gate in Calhoun and Cleburne counties, AL, as well as install a 2.25-mile lateral off SNG’s 20-inch diameter North Mainline Line (see Daily GPI, April 9).
The lateral, which will be three inches in diameter, will be installed parallel to the abandoned loop line segment. The installation of the lateral will be necessary to connect the existing North Main Line to the Heflin Gate Meter Station after the meter station is separated from the abandoned looped segment, according to the order issued by the Federal Energy Regulatory Commission [CP12-112]. The new lateral will provide sufficient capacity to Southern’s existing firm customers at the Heflin Gate Meter Station after the abandonment without any diminution in service, the company said.
The application follows a rupture on the pipeline system in 2009, which SNG and the Department of Transportation’s PHMSA concluded was caused by a wrinkle bend in the North Main Loop Line. The loop line was installed in 1948, according to SNG. At the time, contractors commonly used a process of conforming steel pipe to the surrounding topography by forcefully compressing the pipe to create a bend in it. This technique created what have come to be known as “wrinkle bends” in the pipe.
“Southern’s experience with wrinkle bend failure suggests that the abandoned segment, which contains approximately 438 wrinkle bends and is predominantly located within the Piedmont province, presents an unacceptable risk of future failure in this location,” the FERC order said.
“Although the abandonment will result in a net loss of capacity on Southern’s system, Southern has sufficient capacity on its remaining North Main Line and Main 2nd Loop Line to meet its obligations to existing firm customers…Since the abandonment will have no adverse impact on Southern’s existing transmission services, it is required by the public convenience or necessity.”
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