TRANSWESTERN PIPELINE COMPANY LLC

Incident Narrative

ON NOVEMBER 10, 2011 VERIFICATION DIGS WERE CONDUCTED ON TRANSWESTERN'S (LINE NUMBER AZMM121) 30' PIPELINE AS A RESULT OF AN ILI RUN THAT WAS PERFORMED MAY 12, 2011. THE PIPELINE PRESSURE WAS LOWERED TO 80% OF THE OPERATING PRESSURE PER TRANSWESTERN'S SOP I.11 AND A 40' JOINT OF PIPE WAS EXPOSED IN THE LOCATION SHOWN ON THE ILI DIG SHEET. THE COATING WAS REMOVED FROM THE PIPE AND CORROSION WAS FOUND IN THE LOCATION AS IDENTIFIED ON THE ILI REPORT. THE SURFACE OF THE PIPE WAS SANDBLASTED TO REMOVE THE REMAINING COATING AND THE CORROSION TECHNICIAN BEGAN INSPECTING THE CORRODED AREA TO VERIFY THE ACCURACY OF THE ILI REPORT. THE DEEPEST PIT FOUND IN AN AREA OF GENERAL CORROSION (7.6' LONG X 10.5' WIDE) MEASURED 48% DEEP WITH A LENGTH AND WIDTH OF 0.625'. AFTER ALL THE CORROSION MEASUREMENTS WERE COMPLETED WET MAGNETIC PARTICLE INSPECTION WAS CONDUCTED TO LOOK FOR ANY SIGNS OF SCC CRACKS, THERE WERE NO VISIBLE SIGNS OF SCC. ONCE THE WET MAGNETIC PARTICLE TESTING WAS COMPLETED THE PIPE SURFACE WAS RE-BLASTED TO REMOVE THE WET MAGNETIC PARTICLE MEDIUM AND WHITE CONTRAST PAINT OFF THE PIPE. ONCE THE SANDBLASTING WAS COMPLETED THE CORROSION TECHNICIAN WENT BACK DOWN INTO THE DITCH TO INSPECT THE SURFACE OF THE PIPE FOR COATING REPAIR. WHILE IN THE DITCH THE TECHNICIAN HEARD A LEAK AND IMMEDIATELY NOTIFIED GAS CONTROL AND OPERATIONS MANAGEMENT OF A LEAK (15.43). THE PIPELINE WAS IMMEDIATELY ISOLATED (APPROXIMATELY 16.2 MILES OF PIPELINE) FROM MAINLINE VALVES 2010 AND 2011. AT 16.32 OPERATIONS BEGAN BLOWING DOWN THE PIPELINE. BLOW DOWN WAS COMPLETED AT 21.07 WITH LESS THAN 5PSI LINE PRESSURE IN THE PIPELINE. THE BELL HOLE WAS CHECKED FOR GAS WITH A GAS DETECTOR AND NO GAS WAS DETECTED IN THE DITCH. A FULL ENCIRCLEMENT PRESSURE CONTAINING SLEEVE WAS INSTALLED OVER THE PINHOLE LEAK AND THE PIPELINE WAS RETURNED TO SERVICE ON NOVEMBER 12 AT 18.23 GE PII (MANUFACTURE AND OPERATOR OF THE ILI TOOL) DID A DETAILED ANALYSIS OF THE REPORTED 48% WALL LOSS PIT THAT LEAKED AND CONCLUDED THAT THE DIMENSIONS OF THE PIT WERE BEYOND THE CAPABILITIES OF THE MAGNETIC TOOL TO PROPERLY SIZE THE PINHOLE LEAK. **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.