TRANSCONTINENTAL GAS PIPE LINE COMPANY

Incident Narrative

LOCATING AND VERIFING THE LEAK (JUNE 24, 2013) - TRANSCO RECEIVED INFORMATION FROM APACHE CORP AT 7:30PM ON THE EVENING THE LEAK WAS IDENTIFIED. APACHE PLOTTED OVER TRANSCO'S 10 "" OFFSHORE PIPELINE BETWEEN THE EI 119 - EI 120 PLATFORM, WHICH TIES-IN AT THE 16"" SS128 - EI 129A. APACHE'S MESSAGE TO TRANSCO WAS SIGHTING OF BUBBLES, NO SHEEN REPORTED. GAS CONTROL WAS NOTIFIED (APACHE ALREADY HAD NOTIFIED THE NRC # 1051561) AND TRANSCO RESPONDED WITH SCHEDULING THE INVESTIGATION THE NEXT MORNING. FIELD INVESTIGATION AND THE REPAIR OF THE LEAK (FEBURARY 2014) - TRANSCO PLOTTED THE 16"" LINE, LOCATED AND IDENTIFIED THE LEAK AS BEING A 16"" CHECK VALVE. THE LEAKING VALVE WAS RETRIEVED AND DISASSEMBLED, RESULTS SHOWED THAT DEBRIS WAS FOUND IN THE VALVE FLANGE RING JOINT GROOVES, IDENTIFIED AS THE ORGIN OF THE LEAK. THE VALVE FLANGE RING JOINT GROOVES WERE CLEANED AND THE VALVE REASSEMBLED. IN SUMMARY, THE TRANSCO RCA CONCLUDED THAT THE 16"" CHECK VALVE LEAK WAS THE RESULT OF IMPROPER INSTALLATION OF THE 16"" CHECK VALVE COVER FLANGE, MORE THAN LIKELY ASSOCIATED WITH THE VALVE CLAPPER REMOVAL DURING A 1980 REPAIR. THE 16"" LINE WAS REPESSURED AND THE CHECK VALVE SHOWED NO SIGNS OF LEAKING. THE LINE IS NOW IN FULL OPERATION.