MIDWESTERN GAS TRANSMISSION CO
gas_transmission Incident — — May 1, 2012
Incident Information
| Incident Date | May 1, 2012 |
| Operator | MIDWESTERN GAS TRANSMISSION CO |
| Commodity | NATURAL GAS |
| Pipeline Type | gas_transmission |
Location
| State | |
| Coordinates | 38.44141, -87.17599 |
Cause
| Cause | MATERIAL FAILURE OF PIPE OR WELD |
| Subcause | DESIGN-, CONSTRUCTION-, INSTALLATION-, OR FABRICATION-RELATED |
Casualties
| Fatalities | 0 |
| Injuries | 0 |
Costs
| Property Damage | $12,000 |
| Emergency Response | $0 |
| Other Costs | $0 |
Location Map
Incident Narrative
2"" CROSS-OVER LINE FAILED AT GIRTH WELD CONNECTING 2"" DIAMETER PIPE NIPPLE TO 2"" WELD END VALVE WHICH WAS A BRANCH CONNECTION OFF THE 10"" DIAMETER DISCHARGE HEADER. THE 2"" CROSS-OVER LINE IS LOCATED ON THE SUCTION/DISCHARGE GAS TURBINE UNIT SKID PIPING. THE ACTUAL GAS TURBINE WAS REMOVED IN 2003. THE 2"" CROSS-OVER LINE WAS USED TO PURGE AND LOAD THE COMPRESSOR YARD PIPING, BUT IS NOWBLINDED, CAPPED AND NO LONGER REQUIRED. ONEOK PARTNERS SUPPLIED THE FRACTURED PIPE SECTION TO SHERRY LABORATORIES FOR FAILURE ANALYSIS. BASED ON THE FAILURE ANALYSIS, IT APPEARS FAILURE WAS DUE TO A COMBINATION OF FATIGUE CRACKING AND WELDING DEFECTS IN THE FORMS OF LACK OF FUSION AND INTEGRITY OF THE WELD AND POROSITY IN THE WELD. THE STRESSES RESPONSIBLE FOR THE INITIATION AND PROPAGATION OF THE CRACK WERE A COMBINATION OF APPLIED SERVICE-RELATED CYCLIC LOADING AND RESIDUAL STRESSES FROM THE WELDING FABRICATION. NO MATERIAL DEFECTS IN THE TWO PARENT MATERIALS WERE ASSOCIATED WITH THE PIPE FAILURE.
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.