NORTHERN BORDER PIPELINE COMPANY
gas_transmission Incident — — July 5, 2011
Incident Information
| Incident Date | July 5, 2011 |
| Operator | NORTHERN BORDER PIPELINE COMPANY |
| Commodity | NATURAL GAS |
| Pipeline Type | gas_transmission |
Location
| State | |
| Coordinates | 48.59590, -107.32382 |
Cause
| Cause | EQUIPMENT FAILURE |
| Subcause | MALFUNCTION OF CONTROL/RELIEF EQUIPMENT |
Casualties
| Fatalities | 0 |
| Injuries | 0 |
Costs
| Property Damage | $75,000 |
| Emergency Response | $5,000 |
| Other Costs | $0 |
Location Map
Incident Narrative
THE 1/4"" PILOT VALVE SUPPLY PRESSURE TUBING FAILED, RESULTING IN THE ACTIVATION OF THE MAIN LINE RELIEF VALVE (PSV-5014) AT THE MONCHY FACILITY. TECHNICIAN DISASSEMBLED PILOT VALVE TO INVESTIGATE FOR DAMAGE AND FOUND O-RING FROM THE NOZZLE & SEAT OF PILOT RELIEF VALVE HAD DEGRADATED TO THE POINT OF ALLOWING GAS FLOW IN THE PILOT RELIEF VALVE. THIS RESULTED IN THE PILOT RELIEF VENT LINE TO VENT AT LINE PRESSURE. THE VENTING CAUSED THE VIBRATION ON THE SUPPLY TUBING WHICH IN TURN RUPTURED FROM THIS EXTREME VIBRATION. WHEN THE SUPPLY TUBING FAILED THE 8"" RELIEF BECAME UNSEATED AND CAME FULLY OPEN. THIS PILOT RELIEF VALVE IS CALIBRATED & TESTED ANNUALLY AND IS RE-KITTED WITH A PILOT SOFT GOODS KIT ANNUALLY.
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.