SOUTHERN NATURAL GAS CO — Gas transmission and gathering — incident on 2014-06-30

Gas transmission and gathering incident in YORK, SUMTER County, AL. Reported cause: EQUIPMENT FAILURE. Reported consequences: 0 fatalities, 0 injuries, 48546 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: 20140079.

Operator ID: 18516.

Reported incident date: 6/30/2014 10:20.

Location detail: MILEPOST 102

Cause detail: MALFUNCTION OF CONTROL/RELIEF EQUIPMENT

Cause detail: UPON ARRIVING ON JUNE 30TH AT APPROXIMATELY 10AM CENTRAL TIME TO PERFORM DAILY COMPRESSOR STATION OPERATOR DUTIES AT THE YORK COMPRESSOR STATION, AN OPERATIONS SPECIALIST DISCOVERED THAT THE PRIMARY FUEL GAS RELIEF VALVE WAS VENTING GAS. AFTER APPROXIMATELY 5 MINUTES, THE SPECIALIST WAS ABLE TO STOP THE VENTING BUT DID NOT INFORM SUPERVISION OF THE ABNORMAL OPERATING CONDITION. THE OPERATIONS SPECIALIST, THINKING THAT THE REPORTABLE GAS LOSS FROM THE TIME HE NOTED IT UNTIL THE TIME HE ADDRESSED IT WAS UNDER THE PHMSA LIMIT OF 3000 MCF, DID NOT REPORT THE EVENT TO SUPERVISION. SEPARATELY, AND ALSO ON THE MORNING OF JUNE 30TH, THE MEASUREMENT TECHNICIAN RESPONSIBLE FOR THE YORK FUEL GAS METER RECEIVED A CALL FROM DATA INTEGRITY INFORMING HIM THAT THE DIFFERENTIAL PRESSURE TRANSMITTER FOR THE YORK FUEL GAS METER HAD OVER-RANGED OVER THE WEEKEND AND NEEDED TO BE INVESTIGATED. THE MEASUREMENT TECHNICIAN DROVE TO THE YORK C/S, ARRIVING AT 13:30 PM, BUT DID NOT FIND ANYTHING OUT OF THE ORDINARY. FURTHER INVESTIGATION AND DISCUSSION WITH DATA INTEGRITY, AS WELL AS A REVIEW OF SCADA DATA, DETERMINED THAT THE RELIEF VALVE HAD BEGUN VENTING ON FRIDAY, JUNE 27TH AT APPROXIMATELY 11 PM AND CONTINUED UNTIL THE OPERATIONS SPECIALIST ADDRESSED IT ON MONDAY, JUNE 30TH AT 10AM. IT WAS DETERMINED TO BE REPORTABLE AT 17:45 PM ON JUNE 30, 2014. EXAMINATION OF THE RELIEF VALVE AND REGULATOR DETERMINED THAT THE REGULATOR PILOT SEAT HAD BECOME WORN TO THE POINT WHERE IT ALLOWED GAS TO SEEP PAST IT UNTIL PRESSURE BUILT UP HIGH ENOUGH TO LIFT THE RELIEF VALVE.

PHMSA trend classification: significant incident, not serious.

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

PHMSA indexed costs: $209,719 reported total cost, $145,077.067 in 1984 dollars, $178,132.601 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.