DAPL-ETCO OPERATIONS MANAGEMENT, LLC

Incident Narrative

OPERATOR EMPLOYEE DISCOVERED THE LEAK DURING ROUTINE MORNING WALKDOWN OF FACILITY AT APPROXIMATELY 07:10 AM. CALL WAS PLACED IMMEDIATELY TO THE CONTROL CENTER TO ISOLATE THE STATION FROM THE MAIN LINE. AFTER LEAK WAS ISOLATED AND STOPPED ALL FREE PRODUCT WAS RECOVERED AND CLEANED UP INSIDE PUMP HOUSE. INSPECTION DETERMINED LEAK CAME FROM A CRACK IN A BUTT WELD CONNECTION OF A FLANGE TO A 2"" THERMAL RELIEF LINE AROUND THE DISCHARGE MAIN LINE VALVE. CAUSE OF THE CRACK WAS DETERMINED TO BE EXCESSIVE VIBRATION. SUBSEQUENT TO THE RELEASE THE WELDED CONNECTION WAS REPAIRED. TO PREVENT RECURRENCE THE THERMAL RELIEF LINE HAS BEEN REDESIGNED SO THAT THE ENDS ON EITHER SIDE OF THE MAIN LINE VALVE REMAIN BLIND FLANGED DURING NORMAL OPERATIONS. IF THE DISCHARGE VALVE IS GOING TO BE CLOSED A SPOOL PIECE OF 2"" PIPING WILL BE INSTALLED TO COMPLETE THE RELIEF CIRCUIT WHILE THE VALVE REMAINS CLOSED. THIS DESIGN ELIMINATES THE STRESSES ON THE WELDS CAUSED BY THE VIBRATION. OTHER STATIONS WERE INSPECTED FOR SIMILAR DESIGN AND CIRCUMSTANCES. WHERE IT WAS DETERMINED THAT VIBRATION COULD BE AN ISSUE TEMPORARY BRACING WAS INSTALLED ON THE THERMAL RELIEF LINES UNTIL SUCH TIME A PERMANENT, ENGINEERED SOLUTION IS DESIGNED AND IMPLEMENTED.