ANR PIPELINE CO

Incident Narrative

ON 30 JUNE 2016 AT 13:22 EASTERN TIME (ET), ANR PERSONNEL RECEIVED A CALL FROM A LEASEHOLDER FARMER CONCERNING AN AREA OF DEAD VEGETATION AND POSSIBLE GAS RELEASE NEAR THE PIPELINE RIGHT OF WAY. AN ANR TECHNICIAN WAS DISPATCHED TO THE REPORTED LOCATION TO INVESTIGATE. THE ANR TECHNICIAN ARRIVED AT THE LOCATION AT 14:20 ET. FOLLOWING THE ARRIVAL AND INVESTIGATION OF THE SITE, THE TECHNICIAN CONCLUDED THAT DEAD VEGETATION AND ELEVATED LEVELS OF METHANE, AS MEASURED BY A GAS DETECTOR, IN THE VICINITY OF THE PIPELINE WAS LIKELY DUE TO A GAS RELEASE. THE SUSPECTED GAS RELEASE PROMPTED A CALL TO THE NATIONAL RESPONSE CENTER (NRC) AND AN INCIDENT REPORT (NRC #1152118) WAS FILED AT 15:23 ET ON 30 JUNE 2016. THE SECTION OF PIPE WAS ISOLATED AND THE PRESSURE REDUCED TO ATMOSPHERIC PRESSURE. FOLLOWING EXCAVATION OF THE LOCATION, A GIRTHWELD FEATURE WAS DISCOVERED AND PRESUMED TO BE THE SOURCE OF THE GAS RELEASE. A 14 FOOT SECTION INCLUDING THE GIRTH WELD WAS CUT OUT AND REPLACED WITH NEW PIPE. THE PIPE SECTION CONTAINING THE GIRTH WELD WAS SUBMITTED TO A LABORATORY FOR ANALYSIS. THE PIPELINE WAS PLACED BACK INTO SERVICE ON 31 AUGUST 2016 AT 13:30 LOCAL TIME. LABORATORY ANALYSIS DETERMINED THAT LEAKING FLAW WAS A CONSEQUENCE OF AN INCOMPLETE FUSION ALONG THE ROOT PASS COUPLED WITH POROSITY IN FILL AND CAP FILL PASSES DURING INITIAL FABRICATION. THE INCOMPLETE FUSION AND POROSITY, IN COMBINATION, RESULTED IN AN AREA WHERE THE LOCAL TENSILE CAPACITY WAS LIMITED. DUE TO THE LIMITED BONDING BETWEEN THE WELD SURFACES, MINOR FLUCTUATIONS IN THE TEMPERATURE DURING OPERATIONS CREATED TENSILE STRESSES THAT CONTRIBUTED EXTENSION OF THE WELD IMPERFECTION.