QUESTAR PIPELINE COMPANY
gas_transmission Incident — — September 28, 2011
Incident Information
| Incident Date | September 28, 2011 |
| Operator | QUESTAR PIPELINE COMPANY |
| Commodity | NATURAL GAS |
| Pipeline Type | gas_transmission |
Location
| State | |
| Coordinates | 39.81927, -111.46463 |
Cause
| Cause | EQUIPMENT FAILURE |
| Subcause | MALFUNCTION OF CONTROL/RELIEF EQUIPMENT |
Casualties
| Fatalities | 0 |
| Injuries | 0 |
Costs
| Property Damage | $0 |
| Emergency Response | $300 |
| Other Costs | $0 |
Location Map
Incident Narrative
SUPPLEMENTAL BEING FILED TO CLARIFY THE CAUSE OF THE INCIDENT. DISCHARGE PRESSURES FROM THISTLE CREEK COMPRESSOR STATION WERE OPERATING NEAR THE PRE-SET RELIEF POINT OF THE THERMAL RELIEF VALVE OFF THE DISCHARGE GAS COOLERS. THE RELIEF VALVE BEGAN TO RELIEVE. THE SITUATION WAS IDENTIFIED BY AN OPERATING EMPLOYEE THE NEXT MORNING. THE RELIEF VALVE WAS ISOLATED, MANUALLY RESEATED, AND TESTED TO BE WITHIN 5% OF ITS INTENDED SET-POINT. IT WAS RESET A LITTLE HIGHER, WITHIN DOT LIMITS, AND OPERATING PRESSURES HAVE NOT BEEN NEAR THE SETPOINT SINCE THE INCIDENT OCCURED. INITIALLY, THE ESTIMATED GAS RELEASE WAS 3.79 MMSCF, BUT UPON FINALIZING THE VENTED GAS CALCULATION, IT WAS DETERMINED THAT THE TOTAL VOLUME OF RELEASED GAS WAS 2.28 MMSCF. QUESTAR PIPELINE COMPANY IS FILING THIS REPORT TO FOLLOW-UP WITH THE REPORT MADE TO THE NRC, THOUGH THE FINAL VENTED GAS VOLUME WAS DETERMINED TO BE BELOW THE REPORTING THRESHOLD FOR UNINTENTIONAL RELEASES.
About This Pipeline Incident
Pipeline incident data is reported to the Pipeline and Hazardous Materials Safety Administration (PHMSA). All significant incidents involving fatalities, injuries, or property damage over $50,000 must be reported.