COLUMBIA GAS TRANSMISSION, LLC

Incident Narrative

ON APRIL 3, 2018, AT 15:21 EASTERN STANDARD TIME (EST) COLUMBIA GAS TRANSMISSION, LLC (COLUMBIA) MONITORING CENTER RECEIVED A CALL FROM THE HOCKING COUNTY FIRE DEPARTMENT REGARDING A POTENTIAL NATURAL GAS RELEASE FROM COLUMBIA FACILITY IN NEW STRAITSVILLE, OH. COLUMBIA OPERATIONS PERSONNEL WERE ON SITE AT 16:30 EST AND CONFIRMED THAT THE UNINTENDED GAS RELEASE TO BE FROM LINE H-109. THE INVOLVED SECTION OF LINE H-109 IN THIS EVENT CROSSED-OVER A CREEK (SPAN) AND THE ENTIRE AREA WAS SUBJECT TO HEAVY RAIN DOWNPOURS AND FLOODED. CONSEQUENTLY, THE SPAN SEGMENT OF LINE H-109 WAS COMPLETELY SUBMERGED UNDER WATER. LINE H-109, IS CLASSIFIED AS TRANSMISSION , OPERATED AND MAINTAINED BY COLUMBIA. AT 17:30 EST, THE LEAK WAS ISOLATED AND THE PIPELINE WAS REMOVED FROM SERVICE. BY APRIL 6TH, 2018,THE AREA DEEMED SAFE WHERE THE FLOODED REGION WAS ACCESSIBLE AFTER THE WATER RECEDED. COLUMBIA OPERATIONS PERSONNEL COULD ACCESS AND SURVEY THE FAILURE SITE, IT WAS CONFIRMED THAT LINE H-109 HAD SEPARATED AT THE FAILURE LOCATION. THE INVOLVED SEGMENTS OF LINE H-109 WERE SENT TO A METALLURGICAL FAILURE ANALYSIS LABORATORY TO ESTABLISH THE ROOT CAUSE BEHIND THIS PIPELINE FAILURE. THE 48-HR UPDATE NRC WAS COMPLETED ON APRIL 5, 2018 WITH REPORT NO.1208575. THE METALLURGICAL FAILURE ANALYSIS REPORT OF LINE H-109 IDENTIFIED THAT THERE WAS NO EVIDENCE OF SIGNIFICANT CORROSION ON THE CRACK FACES AND THE MORPHOLOGY OF THE FRACTURE SURFACE IS CONSISTENT WITH LOW CYCLE FATIGUE, INDICATING THAT THE PIPE FAILED UNDER HIGH CYCLIC LOADING OVER A RELATIVELY SHORT PERIOD OF TIME. THE CONSTRUCTION OF THE REPLACEMENT SECTION FOR LINE H-109 WAS COMPLETED BY USING HORIZONTAL DIRECTIONAL DRILLING METHOD FOR INSTALLING PIPE UNDER THE CREEK TO PROTECT THE PIPE FROM SIMILAR WEATHER-RELATED EVENTS. LINE H-109 WAS RETURNED TO SERVICE ON NOVEMBER 7, 2018.