SUNOCO PIPELINE L.P.

Incident Narrative

ON THE AFTERNOON ON 2/11/2022 THE CONTROL CENTER RECEIVED A CALL FROM A 3RD PARTY REPORTING AN EVENT AT THE MOUNT UNION FACILITY. THE LINE WAS NOT OPERATING AT THE TIME AND WAS UNDER STATIC CONDITION. ALTHOUGH THERE WAS NO INDICATION OF A PRODUCT RELEASE ON THE LEAK DETECTION OR SCADA SYSTEMS, CONTROL CENTER PERSONNEL TOOK IMMEDIATE STEPS TO ISOLATE THE STATION AND THEN DRAW PRESSURE AWAY FROM THE DOWNSTREAM SIDE OF THE MOUNT UNION FACILITY. INTERNAL NOTIFICATIONS WERE MADE TO DISPATCH COMPANY AND OSRO PERSONNEL TO THE SITE. WHEN COMPANY PERSONNEL ARRIVED ON SITE IT WAS DISCOVERED THAT THE LAUNCHER ASSOCIATED WITH THE 20-INCH HVL LINE HAD RUPTURED AND HAD RELEASED AN ESTIMATED 13.8 BARRELS OF PROPANE TO ATMOSPHERE. NRC REPORT NO. 1328740 WAS MADE AFTER CONFIRMED DISCOVERY WAS ESTABLISHED. THE FAILED LAUNCHER BARREL WAS ISOLATED FROM THE MAIN LINE AND THE FACILITY PIPING WAS FULLY ISOLATED AND MADE SAFE FOR FURTHER INVESTIGATION AND WORK TO ASSESS THE SITE AND INVESTIGATE THE FAILURE. AFTER ALL PIPING HAD BEEN INSPECTED AND IN CONJUNCTION WITH RESPONDING REGULATORY AGENCIES (PHMSA AND PA PUC) THE PIPELINE SYSTEM WAS RESTARTED ON 2/13/2022 AT 13:32. NOTE: THE SCADA SYSTEM SHOWED THE LINE PRESSURE AS 658PSI. AND THE LEAK DETECTION SYSTEM DID NOT INDICATE A LEAK ON THE MAIN LINE. THE LAUNCHER ASSEMBLY WHICH FAILED WAS ISOLATED FROM THE MAIN LINE AND WAS NOT CONFIGURED WITH A PRESSURE INDICATING DEVICE. ENGINEERING CALCULATED AN ESTIMATED PRESSURE OF 2136 PSI COULD HAVE OCCURRED BASED ON ASSUMPTIONS THE LAUNCHER WAS LIQUID FULL WITH PROPANE AND TAKING INTO ACCOUNT THE TEMPERATURE RISE. THE LAUNCHER WAS EQUIPPED WITH A THERMAL RELIEF VALVE. ROOT CAUSE INVESTIGATION DETERMINED THAT DURING PRIOR MAINTENANCE, PRODUCT WAS INTRODUCED TO THE LAUNCHER AND NOT PURGED AFTER THE MAINTENANCE ACTIVITY. ADDITIONALLY, THE ISOLATION VALVE FOR THE PRESSURE SAFETY VALVE (PSV) ON THE LAUNCHER WAS LEFT IN THE CLOSED POSITION AFTER PRIOR MAINTENANCE THEREBY NOT ALLOWING THE PSV TO FUNCTION CORRECTLY AND LEADING TO THE OVERPRESSURE AND FAILURE OF THE LAUNCHER. THIRD PARTY EXAMINATION OF THE PSV DETERMINED THAT IT WAS FUNCTIONING PROPERLY. THIRD PARTY METALLURGICAL EXAMINATION OF THE FAILED PIPING DETERMINED THAT ALL MATERIAL PROPERTIES WERE COMPLIANT WITH API 5L SPECIFICATIONS AND THAT THERE WERE NO FEATURES THAT WOULD HAVE LED TO A FAILURE PRESSURE LOWER THAN DESIGN.