A section of Millennium Pipeline running from Corning to Ramapo, NY, poses “a pipeline integrity risk to public safety, property or the environment,” an investigation has found. In response to a proposed safety order, the pipeline told shippers it is operating at a reduced pressure; however, scheduled flows were not expected to be interrupted.

In July the U.S. Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA) issued a proposed safety order that, among other things, recommended that Millennium “undertake an assessment of the affected sections [of pipeline] to ensure the overall integrity of girth welds, using in-line inspection methods and pipe examination…Reduce operating pressure on the affected sections so that it does not exceed 80% of the highest actual operating pressure during the 60-day period immediately prior to the discovery of the Jan. 11, 2011 leak [see Daily GPI, July 25].”

The January leak was discovered when operator personnel saw bubbles in a creek in a remote area of Tioga County during a routine inspection, according to PHMSA. The affected sections of pipeline are 30 and 24 inches in diameter.

The cause of the leak was found to be a “pinhole” in a circumferential girth weld joining two pieces of 30-inch diameter pipe. “The weld was characterized as a ‘double joint’ weld, which refers to a mechanized weld that was made to join two lengths of pipe in a staging yard prior to shipping to the final installation site.” PHMSA said in its proposed safety order.

The agency went on to say that records show that the double joint pipe section did not pass a visual inspection and was set aside where it was inadvertently picked up later and installed in the pipeline.

“The established maximum allowable operating pressure (MAOP) of the 30- and 24-inch [diameter] sections of the pipeline is 1,200 pounds per square inch gauge (psig). A hydrostatic test was performed on Nov. 11, 2008 following construction of the pipeline to establish the 1,200 MAOP,” PHMSA said. “The actual operating pressure of the line at the time of the discovery of the leak was approximately 1,070 psig.”

A Millennium spokesperson was not immediately available to comment. In its customer notice Millennium said that if it experiences a sharp increase in nominations, shippers could be impacted because of the MAOP curtailment through segments at Corning East, Wagoner East, Stagecoach East and Greenwood Lake.

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