COLUMBIA GAS TRANSMISSION CORP — Gas transmission and gathering — incident on 2012-10-30

Gas transmission and gathering incident in FLAT TOP, SUMMERS County, WV. Reported cause: EQUIPMENT FAILURE. Reported consequences: 0 fatalities, 0 injuries, 6850 NATURAL GAS released, $0 reported property damage. Operator-reported incident data submitted to PHMSA, generally within 30 days. Records may be supplemented or corrected and do not represent final agency causal findings.

Report number: 20120118.

Operator ID: 2616.

Reported incident date: 10/30/2012 13:30.

Location detail: BLOWDOWNVLV

Cause detail: MALFUNCTION OF CONTROL/RELIEF EQUIPMENT

Cause detail: HURRICANE SANDY SIGNIFICANTLY IMPACTED THE WEST VIRGINIA MOUNTAINS ON THE EVENING OF OCTOBER 29, WITH LESSENING IMPACTS FOLLOWING. DAMAGE FROM THIS HEAVY, EARLY SEASON SNOWSTORM IN THE WEST VIRGINIA MOUNTAINS INCLUDED LOSS OF POWER AND COMMUNICATIONS FOR MUCH OF THE REGION. AMONG THE FACILITIES AFFECTED IN THE REGION WAS THE FLAT TOP COMPRESSOR STATION. AT THE TIME THE STORM HIT, THE COMPRESSOR STATION WAS UNATTENDED. WHEN THE COMMUNICATION LOSS WAS RECOGNIZED ON THE MORNING OF OCTOBER 30, AN EMPLOYEE WAS DISPATCHED TO THE LOCATION TO INVESTIGATE. THE EMPLOYEE ARRIVED AT THE STATION AT APPROXIMATELY 9:30 A.M. NOT LONG AFTER ARRIVAL, HE HEARD GAS VENTING. THIS WAS NOT UNUSUAL, AS THE TURBINE UNIT IS DESIGNED TO BLOW DOWN IF IT GOES OFFLINE AS HAD APPARENTLY HAPPENED. A SHORT WHILE LATER, AS THE EMPLOYEE CONTINUED TO RESTORE STATION OPERATION, HE RECOGNIZED THAT GAS WAS STILL VENTING. THIS WAS UNUSUAL, AS THE BLOWDOWN PROCESS SHOULD HAVE BEEN COMPLETE BY THEN, EVEN IF IT HAD BEGUN JUST PRIOR TO THE EMPLOYEE'S ARRIVAL. AFTER CAREFULLY ASSESSING THE SITUATION, THE EMPLOYEE MANUALLY CLOSED THE BLOWDOWN VALVE. FURTHER INVESTIGATION REVEALED THAT A PARTIAL ESD HAD OCCURRED DURING THE COMMUNICATION LOSS / POWER LOSS EVENT, AND THE BLOW DOWN VALVE HAD REMAINED IN THE OPEN POSITION. CORRECTIVE ACTIONS TAKEN ON 10-30-2012 1. THE STATION COMPRESSED AIR SYSTEM WAS RECHARGED USING THE EMERGENCY GASOLINE POWERED AIR COMPRESSOR. 2. THE UNIT SUCTION VALVE WAS MANUALLY CLOSED TO STOP GAS FROM VENTING. 3. THE EMERGENCY BACKUP GENERATOR WAS STARTED AND AC POWER RESTORED. 4. THE 24 VOLT ESD SHUNT TRIP BREAKER WAS RESET AND 24 VOLT DC POWER RESTORED. 5. THE STATION WAS RETURNED TO NORMAL OPERATIONAL STATUS WITH AC POWER BEING SUPPLIED BY THE EMERGENCY BACKUP GENERATOR. COLUMBIA'S ENGINEERING SERVICES COMPLETED AN INVESTIGATION WITH A RECOMMENDATION TO UPGRADE THE SUCTION VALVE ACTUATOR FROM ELECTRIC TO FAIL CLOSED PNEUMATIC.

PHMSA trend classification: not significant, not serious.

PHMSA standardized cause: EQUIPMENT FAILURE — MALFUNCTION OF CONTROL/RELIEF EQUIPMENT.

PHMSA indexed costs: $20,619 reported total cost, $17,218.827 in 1984 dollars, $21,142.104 in current-year dollars.

PHMSA trend flags, standardized causes, and indexed costs are analytical fields added to operator-reported incident data. They do not represent final agency causal findings.