PACIFIC GAS & ELECTRIC CO

Incident Narrative

ON OCT. 15, 2014 DURING A ROUTINE LEAK SURVEY, A NON-HAZARDOUS LEAK WAS DISCOVERED AT THE CASING VENT ON PG&E'S TRANSMISSION LINE L-132 AT MILE POINT 3.07. THE 30-INCH CASING AND 24-INCH DIAMETER TRANSMISSION PIPE L-132 CROSS BENEATH THE UNION PACIFIC RAIL ROAD NEAR LAFAYETTE AND GIANERA STREETS. IN RESPONSE, PG&E IMMEDIATELY BEGAN EXCAVATIONS TO ASSESS THE PIPE CONDITION ON OCTOBER 15, 2014. AN EMERGENCY EXCAVATION NOTICE WAS SENT TO THE CPUC ON OCTOBER 16 REGARDING THIS MATTER. THE CASING ENDS WERE EXCAVATED, THE NON-HAZARDOUS LEAK HAS BEEN DETERMINED TO ORIGINATE FROM THE BOTTOM OF THE CARRIER PIPE. THE CAUSE OF THE LEAK IS DUE TO MICROBIOLOGICAL EXTERNAL CORROSION. ON OCTOBER 23, 2014, PRESSURE FOR L-132 WAS LOWERED 20% (FROM 285 PSIG TO 228 PSIG) AND A SAFETY RELATED CONDITION REPORT WAS SUBMITTED TO THE DOT AND CPUC. THIS INCIDENT WAS REPORTED TO THE DOT AND CPUC ON OCTOBER 29, 2014 UPON DETERMINATION THAT RESPONSE COSTS ARE ESTIMATED TO EXCEED $50,000. THERE ARE NO INJURIES, NO FATALITIES, AND NO IGNITION. NO MEDIA WAS OBSERVED ON SCENE. A LIQUEFIED NATURAL GAS (LNG) INSTALLATION NOTIFICATION WAS SENT TO THE CPUC ON NOVEMBER 13, 2014 IN THE EVENT THAT ADDITIONAL GAS SUPPLY WAS REQUIRED TO PREVENT THE LOSS OF CUSTOMERS DURING REPAIRS. DURING THE SHUTDOWN OF THE TRANSMISSION LINE, THE FEED TO THIS CRITICAL REGULATOR STATION WAS TEMPORARILY SUPPLIED WITH COMPRESSED NATURAL GAS (CNG), AS TEMPERATURES WERE MILD AND THE LNG SUPPORT WAS NOT REQUIRED. ON NOVEMBER 19, PG&E INSTALLED THE NEW 24-INCH PIPE INTO THE EXISTING 30-INCH CASING. BY NOVEMBER 21 AT APPROXIMATELY 2313 HOURS, PG&E COMPLETED TIE-IN AND RETURNED L-132 TO NORMAL OPERATING PRESSURE OF 285 PSIG.