TRANSWESTERN PIPELINE COMPANY LLC

Incident Narrative

AN ILI TOOL WAS RUN ON THE PANHANDLE LATERAL (TXBP132) ON MARCH 9, 2010. THE ILI COMPANY NOTED DURING THE INITIAL EVALUATION OF THE DATA FROM THE ILI TOOL, THAT AN ANOMALY WAS DETECTED AND MAY HAVE A WALL LOSS GREATER THAN 70% OF THE WALL THICKNESS OF THE PIPE. WITHIN A FEW HOURS OF NOTIFICATION TO TW, THE PIPELINE WAS REDUCED IN PRESSURE AND AN EXCAVATION CREW WAS SENT OUT TO THE SITE. DURING THE BELL HOLE INVESTIGATION GAS DRIED SOIL WAS NOTED, SO THE EXCAVATION WAS TEMPORARILY STOPPED UNTIL A GAS DETECTOR HAD ""SNIFFED"" THE AREA FOR GAS. THE GAS DETECTOR INDICATED A HIGH PPM OF METHANE GAS SO ALL CONSTRUCTION WAS STOPPED UNTIL THE PIPELINE WAS BLOWN DOWN TO ATMOSPHERE. CONTINUED INVESTIGATION FOUND A PIN HOLE LEAK UNDER A THERMITE WELD THAT WAS PARTIALLY BONDED TO THE PIPE. THE THERMITE WELD CONNECTED BOTH THE NEGATIVE HEADER CABLE THAT GOES TO THE RECTIFIER AND THE TEST LEAD WIRE THAT GOES TO THE CP TEST STAND. THE THERMITE WELD WAS EASILY REMOVED WITH JUST A SMALL PULL ON THE WIRING. THE NEGATIVE HEADER CABLE LEAD WAS A TRIANGLE PWC, INC S N-A 1-AWG TYPE THHN/THWN, GASOLINE AND OIL RESISTANT WIRE. THE INSULATION ON THE WIRE HAD BEEN HEATED AND HAD MELTED THE INSULATION BACK APPROXIMATELY 3.5 INCHES FROM THE THERMITE CONNECTION. SOME OF THE METAL CABLE STRANDS WHERE THE INSULATION HAD MELTED BACK SHOWED DISCOLORATION. ADDITIONALLY THERE WAS A SMALL AMOUNT OF DISCOLORATION ON THE SURFACE OF THE PIPE SURROUNDING THE LEAK. NO CORROSION, DENTS, CRACKS OR GOUGES WERE FOUND ON THE SURFACE OF THE PIPE. THE LEAK WAS THE SIZE OF A PIN HOLE AND APPEARS TO HAVE OCCURRED DUE TO ELECTRICAL ARCING FROM THE NEGATIVE HEADER CABLE TO THE PIPE SURFACE. CORROSION TECHNICIAN REPORTS THE CPU UNIT ""SIMMS"" WAS INSTALLED IN AUGUST 1990, AND IS SUBJECT TO HIGH LIGHTNING STRIKES AND POWER SURGES. THE RECTIFIER HAS BEEN STRUCK BY LIGHTING A NUMBER OF TIMES BLACKING THE INSIDE OF THE RECTIFIER CASE. ON ONE OCCURRENCE, A LIGHTING STRIKE DISLODGED THE CONNECTION BLOCK FROM THE CASE OF THE RECTIFIER. THE CORROSION TECHNICIAN INSTALLED A SURGEX UNIT IN JUNE 2000 TO HELP REDUCE THE NUMBER OF REPAIRS TO THE RECTIFIER AND MINIMIZE DAMAGE FROM LIGHTING STRIKES. THE RECTIFIER UNIT IS LOCATED WITHIN 30 FT FROM WHERE THE LEAK OCCURRED. TRANSWESTERN DID A THROUGH REVIEW OF CP RECORDS FROM 2003 AND FOUND NO INDICATION OF THE CP PROBLEMS OR A CHANGE IN THE CP SYSTEMS CIRCUIT RESISTANCE. THE OVER ALL CIRCUIT RESISTANCE WAS FROM 0.47 OHMS TO 0.85 OHMS. THE PIPE TO SOIL POTENTIALS ARE BETWEEN -3 TO -4 VOLTS, WITH INSTANT OFF READINGS BETWEEN -1 TO -1.25 VOLTS. THE HIGH VOLTAGE POTENTIALS ARE ASSOCIATED WITH THE CP GROUND BED BEING LOCATED WITHIN 30 FT. OF THE PIPELINE. CONCLUSION ' THE CAUSE OF THE LEAK IS ATTRIBUTED TO METAL LOSS FROM ELECTRICAL ARCING BETWEEN THE NEGATIVE HEADER CABLE AND THE PIPE SURFACE FROM LIGHTING STRIKES. A PREVIOUS ILI TOOL RUN THAT WAS CONDUCTED MARCH 2003 SHOWED NO WALL LOSS ANOMALY'S AT THIS LOCATION. **THIS REPORT IS BEING SUBMITTED IN RESPONSE TO PHMSA'S REQUEST, (DOCKET ID PHMSA-2013-0028), FOR SUPPLEMENTAL REPORTS FROM OPERATORS WHO SUBMITTED REPORTS FOR INCIDENTS OCCURRING AFTER JANUARY 1, 2010, WITH ANY OF THE FOLLOWING: (1) ``PIPE GIRTH WELD'' WAS SELECTED AS THE ``ITEM INVOLVED IN INCIDENT'' IN PART C3 OF THE REPORT. THE REVISED REPORT COLLECTS DATA ABOUT THE PIPE ADJACENT TO THE GIRTH WELD. (2) ``FUNCTION OF PIPELINE SYSTEM'' IS NULL IN PART E5F OF THE REPORT. THE REVISED REPORT COLLECTS THE FUNCTION OF THE PIPELINE SYSTEM FOR ALL INCIDENTS.** THIS SUPPLEMENTAL REPORT IS TO ACKNOWLEDGE THAT THE TWO RELEVANT SECTIONS IN PHMSA'S REQUEST HAVE BEEN REVIEWED AND NO FURTHER ACTIONS WERE NEEDED.