COLUMBIA GULF TRANSMISSION, LLC

Incident Narrative

ON MAY 21, 2015, COLUMBIA GULF TRANSMISSION, LLC (COLUMBIA) RECEIVED AN ALARM FROM RAYNE COMPRESSOR STATION (CS) FACILITY REGARDING AN EMERGENCY SHUTDOWN (ESD). COLUMBIA PERSONNEL WERE DISPATCHED TO INVESTIGATE THIS ALARM. UPON ARRIVING AT THE SITE, COLUMBIA PERSONNEL NOTED THAT THE FACILITY WAS IN AN ESD MODE AND MATERIAL WAS STILL VENTING INADVERTENTLY INTO ATMOSPHERE. THE FACILITY WAS INSPECTED TO IDENTIFY THE LOCATION OF THE OPEN VALVE IN ORDER TO ACT ACCORDINGLY. THE COLUMBIA PERSONNEL DISCOVERED AN 8-IN ESD VALVE IN THE OPEN POSITION. COLUMBIA PERSONNEL ASKED FOR ASSISTANCE TO MANUALLY OVER-RIDE THIS VALVE. AFTER 21 MINUTES, THE VALVE STOPPED FLOWING MATERIAL AND THE FACILITY WAS PUT INTO SAFE OPERATION. FOLLOWING THE INCIDENT, COLUMBIA ASSEMBLED AN INVESTIGATIVE TEAM FROM COMPRESSION, AUTOMATION AND ELECTRICAL GROUPS IN ADDITION TO THE VALVE MANUFACTURER, IN ORDER TO INVESTIGATE AND HELP ASSEMBLE THE CHAIN OF EVENTS THAT LED THIS 8-IN ESD VALVE FROM FAILING TO CLOSE. PRELIMINARY INDICATIONS FOCUSED ON A SOFTWARE GLITCH WHICH LED TO INITIATE THIS ESD EVENT AND FALSE SIGNAL BY THE CONTROL PROCESSING UNIT TO INITIATE PROPER SIGNALS TO STOP THE MATERIAL FROM FLOWING INADVERTENTLY INTO ATMOSPHERE. THE FAULTY VALVE WAS ISOLATED AND WAS NOT RETURNED BACK INTO SERVICE UNTIL AN INVESTIGATION WAS COMPLETED TO ENSURE THAT THAT THE SAME HARDWARE ERROR WILL NOT TRIGGER ANOTHER EVENT. THE ESD SYSTEM WAS RETURNED BACK INTO SERVICE ON JUNE 12, 2015. DURING THIS TIME, THE CS WAS MANNED. THE KEY LESSONS IDENTIFIED FROM THIS INCIDENT WAS THAT COLUMBIA PERSONNEL TO ASSURE QUARTER TURN VALVES ARE IN THE OPEN POSITION AFTER ANY VALVE MAINTENANCE IS PERFORMED AND TO PERIODICALLY CHECK THE CENTRAL PROCESSING UNIT AREA FOR ANY FUTURE SIGNS OF TAMPERING OR EVIDENCE OF RODENTS. INITIAL INCIDENT REPORT WAS SUBMITTED ON JUNE 18, 2015