ENABLE GAS TRANSMISSION, LLC

Incident Narrative

WHILE PERFORMING A CLOSE INTERVAL SURVEY, AN ENABLE DIRECT ASSESSMENT (DA) CREW, DISCOVERED A LEAK ON LINE KT-1. UPON DISCOVERY, THE DA CREW NOTIFIED THE LOCAL ENABLE MIDSTREAM OPERATING PERSONNEL WHO ASSESSED THE SITUATION AND CONFIRMED THE LEAK TO BE ON KT-1 AT 13:38. THE ENABLE MIDSTREAM ON-CALL TEAM WAS NOTIFIED AND A NOTIFICATION CALL WAS PLACED TO THE NRC (NRC# 1189935 9/11/2017 14:14 CST). A 48 HOUR FOLLOW UP CALL (NRC#1190154) WAS PLACED ON 9/13/17 AT 11:11 CST. AT THE LEAK LOCATION, KT-1 CONSISTS OF GRADE B STEEL, 10.75, .188 W.T. PIPE. IT WAS INSTALLED IN CLAIBORNE PARISH LA IN 1942. LINE KT-1 WAS REPAIRED WITHOUT BEING TAKEN OUT OF SERVICE, BY PLACING STOPPLES BOTH UPSTREAM AND DOWNSTREAM OF THE LEAK SITE WITH A BYPASS. WHEN COMPLETED, THE LEAKING SECTION OF PIPE WAS REMOVED AND INVESTIGATED FURTHER. THE LEAK WAS FOUND TO BE LOCATED AT A CIRCUMFERENTIAL GIRTH WELD AT A CREEK CROSSING. IT HAS BEEN DETERMINED THAT SEVERAL FACTORS CONTRIBUTED TO THE LEAK ON KT-1. - THIS PIPE HAS BEEN PREVIOUSLY EXPOSED IN A SEASONAL CREEK CROSSING AND WAS SUBJECT TO ATMOSPHERIC CORROSION WHEN THE WATER LEVEL RECEDED. - LOW CATHODIC PROTECTION LEVELS WERE PREVIOUSLY FOUND DUE TO THE PRESENCE OF NEARBY DRESSER COUPLINGS. ALTHOUGH THESE LOW LEVELS OF CP WERE REMEDIATED, CORROSION HAS PREVIOUSLY OCCURRED. - IN 2012, THE CREEK CROSSING WAS REMEDIATED BY ADDING GROUND COVER. THE PIPE APPEARS TO HAVE EXPERIENCED STRESS FROM ADDED WEIGHT ABOVE PIPE GRADE AND LACK OF SUPPORT BELOW PIPE GRADE. THE REMAINING WALL THICKNESS AT THE GIRTH WELD APPEARS TO HAVE MECHANICALLY FAILED DUE TO THIS STRESS. A FINAL REPAIR COST CANNOT BE PROVIDED AT THIS TIME AND A SUPPLEMENTAL REPORT WILL BE SUBMITTED WHEN IT CAN BE DETERMINED.