TENNESSEE GAS PIPELINE CO (EL PASO)

Incident Narrative

ON MARCH 1, 2011, TENNESSEE GAS PIPELINE (TGP) COMPANY PERSONNEL ARRIVED TO BEGIN THEIR WORK DAY AT COMPRESSOR STATION 209 NEAR CUMBERLAND, OHIO, AND NOTICED AN AUDIBLE SOUND LIKE RELEASING GAS JUST NORTHEAST OF THE STATION YARD. UPON INVESTIGATION, THE POINT OF THE RELEASE WAS FOUND IN TGP'S 26"" 200-1 PIPELINE. ISOLATION VALVES WERE CLOSED AND THE SECTION OF PIPE WAS DEPRESSURIZED. THERE WAS NO ASSOCIATED FIRE OR EXPLOSION. A ROOT CAUSE ANALYSIS HAS DETERMINED THE CAUSE TO BE THE FAILURE OF A GIRTH WELD IN THE FORM OF A CRACK THAT ORIGINATED AT INTERNAL UNDERCUTTING AT THE TOE OF THE GIRTH WELD ROOT PASS AND EXTENDING THROUGH THE WELD METAL OF THE WELD, ALSO ASSISTED BY TENSILE AXIAL STRESSES DUE TO THERMAL STRESS AT THE LOW AMBIENT TEMPERATURE WITH NO GAS FLOW AND BENDING STRESS AT THE SAG BEND.. THE CRACK WAS LIKELY PRODUCED DURING THE INITIAL WELDING PROCESS AND RAN FROM THE 9 O'CLOCK POSITION TO THE 3 O'CLOCK POSITION AROUND THE PIPE. THE DEFICIENT WELD WAS REMOVED, NEW PIPE INSTALLED, AND THE SECTION HAS BEEN PLACED BACK INTO SERVICE. YEAR OF PIPE MANUFACTURE IS ASSUMED TO BE COMMENSURATE WITH YEAR OF INSTALLATION 2/10/2015 - PART C - TYPE OF INCIDENT CHANGED FROM ""LEAK"" TO ""RUPTURE"". 3/27/2015 - PART E - UPDATED MAOP DETERMINATION METHOD TO 192.619(A)(3). 7/20/2015 - PART A - LOCAL TIME OF INCIDENT REVISED FROM TIME OF DETERMINATION AT 8:00 TO TIME THAT TGP PERSONNEL HEARD HISSING AT 7:15 AM. TIME OF TELEPHONIC REPORT TO THE NRC REVISED FROM 9:15 TO 10:12. BOTH REVISIONS BASED UPON INPUT FROM PHMSA.