ENABLE GAS TRANSMISSION, LLC

Incident Narrative

THE AM-53 PROJECT INVOLVED REPLACING APPROXIMATELY 10,000 FEET OF 10"" DRESSER COUPLED PIPELINE ON THE EGT INTERSTATE SYSTEM. THE SOUTHERN END OF THE PROJECT WAS DESIGNED TO TIE INTO EXISTING PIPE INSTALLED IN 1994 WHILE THE NORTHERN END OF THE PROJECT WAS DESIGNED TO TIE INTO EXISTING PIPE INSTALLED IN 1970. DOING THIS WOULD REMOVE ALL THE ORIGINAL 1936 VINTAGE, DRESSER COUPLED PIPE IN THIS AREA. ON DEC 12, 2017, AFTER THE LINE REPLACEMENT WAS COMPLETED AND FLOWING GAS, CONSTRUCTION CREWS BEGAN TO COLD CUT AND CAP THE NOW OUT-OF-SERVICE SEGMENT CONTAINING THE DRESSER COUPLES. THE SOUTH END WAS CUT FIRST, REMOVING A SHORT SEGMENT OF 1936 VINTAGE PIPE, AND INSTALLING A WELD CAP. CONSTRUCTION CREWS MOVED TO THE NORTH END OF THE PROJECT TO COMPLETE THE SAME TASKS. A SHORT SECTION OF PIPE WAS REMOVED IN PREPARATION FOR A WELD CAP WHEN AN UNDETECTED DRESSER COUPLING ROUGHLY 20 FEET UPSTREAM OF THE STOPPLE SEPARATED FROM THE IN-SERVICE LINE. THE UNDETECTED COUPLING IS A 10X16 INSULATED SLEEVE INSTALLED IN 1970. THE 20' SECTION OF THE UNDERGROUND PIPE CAME LOOSE AND SHIFTED IN THE DITCH CAUSING ONE CONTRACTOR BE INJURED. THE CONTRACTOR WAS TRANSPORTED TO A LOCAL HOSPITAL WHERE THEY RECEIVED TREATMENT BEYOND FIRST AID. ANOTHER CONTRACTOR RECEIVED FIRST AID AT THE SCENE. ALMOST IMMEDIATELY, ALL SOURCES FOR AM-53 WERE CLOSED AND GAS FLOW WAS STOPPED, INTERRUPTING SERVICE IN TOTAL TO 5,400 CERC CUSTOMERS. SERVICE TO CERC WAS RESTORED AT APPROXIMATELY 4:30 PM ON DECEMBER 13TH. PHMSA WAS INITIALLY NOTIFIED 12/1217 AT 17:07 (NRC#1199503) AND A 48 HOUR FOLLOW UP WAS PROVIDED ON 12/14/17 AT 09:26 (NRC#1199628). THE INVESTIGATION DISCOVERED VERTICAL AND LATERAL STABILITY WAS REMOVED FROM LINE AM-53 WHEN 14' OF 1936 VINTAGE DRESSER COUPLER LINE WAS REMOVED IN PREPARATION FOR A WELD CAP. PULLOUT OCCURRED OF AN UNDETECTED 10X16"" STYLE 40 DRESSER COUPLER (14' UPSTREAM, NEAR 193+69) FROM THE IN-SERVICE LINE. BOTH DRESSER COUPLERS IN THIS AREA (VINTAGE 1936 10X8"" AND VINTAGE 1970 10X16"") WERE NOT ANCHORED. SUPPLEMENTAL REPORT 3/22/18 SUMMARY OF CHANGES D.7.A WAS CHANGED FROM A PROJECTION OF $275,000 TO ACTUAL 95,786 H. THE NARRATIVE WAS UPDATED TO INCLUDE : VERTICAL AND LATERAL STABILITY WAS REMOVED FROM LINE AM-53 WHEN 14' OF 1936 VINTAGE DRESSER COUPLER LINE WAS REMOVED IN PREPARATION FOR A WELD CAP. PULLOUT OCCURRED OF AN UNDETECTED 10X16"" STYLE 40 DRESSER COUPLER (14' UPSTREAM, NEAR 193+69) FROM THE IN-SERVICE LINE. BOTH DRESSER COUPLERS IN THIS AREA (VINTAGE 1936 10X8"" AND VINTAGE 1970 10X16"") WERE NOT ANCHORED.