EQT MIDSTREAM — Gas transmission and gathering — incident on 2012-04-07

Gas transmission and gathering incident in WESTON, LEWIS County, WV. Reported cause: EQUIPMENT FAILURE. Reported consequences: 0 fatalities, 0 injuries, 11200 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: 20120044.

Operator ID: 31604.

Reported incident date: 4/7/2012 1:48.

Location detail: 130+20 GSF943

Cause detail: MALFUNCTION OF CONTROL/RELIEF EQUIPMENT

Cause detail: AT APPROXIMATELY 1:12 AM APRIL 7, 2012 GAS CONTROL RECEIVED AN ALARM FOR COPLEY COMPRESSOR STATION (544 COPLEY ROAD, WESTON, WV 26452-7174) UNIT #5 COMPRESSOR SHUT DOWN. GAS CONTROL IMMEDIATELY CONTACTED THE ON-CALL EQT COMPRESSOR TECHNICIAN WHO REPORTED TO THE SITE. THE COPLEY STATION ESD TRIPPED AT APPROXIMATELY 1:48 AM WHILE THE COMPRESSOR TECHNICIAN WAS EN ROUTE. THE COMPRESSOR TECHNICIAN ARRIVED AT THE SITE AT APPROXIMATELY 2:03 AM AND DETERMINED ALL ESD VALVES DID NOT CLOSE AND GAS WAS VENTING TO THE ATMOSPHERE. THE COMPRESSOR TECHNICIAN PROCEEDED TO SHUT OFF ONE BLOCK VALVE THAT WAS 100% OPEN AND TWO BLOCK VALVES THAT WERE 20% OPEN. THE VALVES WERE CLOSED AND GAS SHUT OFF AT APPROXIMATELY 2:08 AM. EQT FACILITIES ENGINEERING INVESTIGATED AND DETERMINED TWO OF THREE AIR COMPRESSORS THAT HOLD THE COPLEY AIR SYSTEM PRESSURE UP HAD SHUT DOWN ON HIGH TEMPERATURE. THE THIRD AIR COMPRESSOR COULD NOT HOLD THE SYSTEM UP AND WHEN THE AIR PRESSURE DECLINED BELOW 100 PSIG THE SYSTEM WENT INTO ESD. THERE WAS NOT ENOUGH SUPPLY AIR IN THE SYSTEM TO FULLY SHUT THREE OF THE ESD VALVES. DESIGN ENGINEERING CALCULATED THE GAS LOSS TO BE 11.2 MMCF WHICH REQUIRED AN INCIDENT REPORT FILING.

PHMSA trend classification: not significant, not serious.

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

PHMSA indexed costs: $23,608 reported total cost, $19,653.247 in 1984 dollars, $24,261.28 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.