ENTERPRISE PRODUCTS OPERATING LLC

Incident Narrative

ON 10/19/2015, DURING A FIELD INSPECTION, A SMALL LEAK WAS IDENTIFIED ON THE ENTERPRISE AEGIS 20 INCH MAINLINE VALVE 14101 AT SULPHUR STATION WITH A MX-6 LEL METER. THE LEAK WAS AROUND BONNET FLANGE GASKET WHILE IN THE OPEN POSITION. THE ETHANE LEAK WAS ONLY DETECTABLE WITHIN CLOSE PROXIMITY TO THE BONNET FLANGE BOLTS. THE VALVE WAS CLOSED AND THE BODY WAS BLOWN DOWN WITH NITROGEN AND THE LEAK STOPPED. AT THAT TIME, IT WAS ESTIMATED APPROXIMATELY 2 GALLONS OF ETHANE WAS RELEASED AND, THEREFORE, THE LEAK DID NOT MEET ACCIDENT REPORTING CRITERIA. THE MANUFACTURER SENT A REPRESENTATIVE TO THE SITE TO RE-TORQUE THE BONNET FLANGE BOLTS WITHOUT SUCCESS. ON 10/29/2015, ENTERPRISE MADE THE DECISION TO REPLACE THE VALVE USING A STOPPLE BYPASS AND, AS A RESULT, BASED ON THE PROJECTED COST OF THE REPAIR, THE LEAK MET ACCIDENT REPORTING CRITERIA. THE NRC AND PHMSA WERE BOTH IMMEDIATELY NOTIFIED. THE VALVE REPLACEMENT HAS BEEN COMPLETED AND NO ISSUE WERE NOTED WITH NEW VALVE BONNET SEAL. THE LEAKING VALVE WAS RETURNED TO SOUTHERN CALIFORNIA VALVE FOR EVALUATION. DISASSEMBLY/REMOVAL OF THE BONNET AND INSPECTION OF THE SEAL AREA REVEALED THE BODY/BONNET SPIRAL WOUND GASKET SHOWED TO BE COMPRESSED EVENLY, HOWEVER, THE OUTER RING OF THE SPIRAL WOUND GASKET HAD EXTRUDED IN A SMALL SECTION OF THE GASKET. IT IS BELIEVED THE CAUSE OF THE BONNET LEAK WAS THE SPIRAL WOUND FLAT GASKET OUT RING EXTRUDED WHICH HAD IMPACT ON THE O-RING SEALING SURFACE. THIS GASKET EXTRUSION IS NOT A NORMAL OCCURRENCE AND APPEARS TO BE AN ISOLATED INCIDENT.