COLUMBIA GAS TRANSMISSION, LLC

Incident Narrative

ON OCTOBER 9TH, 2016, GRANT COMPRESSOR STATION (CS) WAS SUBJECT TO AN UNINTENDED EMERGENCY SHUTDOWN (ESD) EVENT THAT WAS DUE TO A FAULTY 4 INCH BLOWDOWN VALVE ACTUATOR. GRANT IS A TRANSMISSION CS THAT IS OPERATED AND MAINTAINED BY COLUMBIA GAS TRANSMISSION, LLC (COLUMBIA). GRANT CS IS LOCATED IN MINGO COUNTY, NEAR THE TOWN OF DELBARTON, WEST VIRGINIA. AFTER THE UNINTENDED RELEASE OF NATURAL GAS (MATERIAL) INTO ATMOSPHERE INITIATION, THE BLOWDOWN VALVE CONTINUED FLOWING MATERIAL UNTIL IT WAS MANUALLY SHUT CLOSED POSITION. COLUMBIA PERSONNEL INSPECTED THE FACILITY AND SECURED OTHER VALVES UNTIL FURTHER INVESTIGATION STARTS. COLUMBIA'S ENGINEERING SERVICES INVESTIGATED THE EVENT AND CAUSAL ANALYSIS INVESTIGATION INDICATED THAT THE 4 INCH BLOWDOWN VALVE FAILED TO REMAIN SHUT DUE TO A FAULTY ACTUATOR ON THIS VALVE. HENCE, RELEASING MATERIAL INTO ATMOSPHERE. THE AMOUNT OF MATERIAL RELEASED INTO ATMOSPHERE WAS CALCULATED TO BE 3,083 MCF. THE INVESTIGATION TEAM FOUND THAT THE VALVE'S ACTUATOR HAD A FAULTY SIGNAL THAT MAY HAVE INITIATED THE UNINTENDED SIGNAL TO OPEN THE VALVE AND START THE ESD SEQUENCE. SEVERAL COMPONENTS WERE REPLACED INCLUDING BUT NOT LIMITED TO THE RELIEF VALVE, THE REGULATOR (FOR THE POWER GAS SYSTEM) AND A RESETTING TO THE RELIEF VALVE'S SET-POINT TOO. THE VALVES WERE TESTED AND THE FACILITY WAS RETURNED BACK IN SERVICE AND WAS MONITORED THROUGHOUT THE DAY FOR ANY ABNORMAL FUNCTIONALITY OF ANY OF THE INVOLVED COMPONENTS IN THIS INCIDENTS. NO FURTHER ISSUES WERE IDENTIFIED.