MICHIGAN CONSOLIDATED GAS CO (MICHCON)
gas_transmission Incident — — February 23, 2011
Incident Information
| Incident Date | February 23, 2011 |
| Operator | MICHIGAN CONSOLIDATED GAS CO (MICHCON) |
| Commodity | NATURAL GAS |
| Pipeline Type | gas_transmission |
Location
| State | |
| Coordinates | 42.78704, -82.52859 |
Cause
| Cause | MATERIAL FAILURE OF PIPE OR WELD |
| Subcause | DESIGN-, CONSTRUCTION-, INSTALLATION-, OR FABRICATION-RELATED |
Casualties
| Fatalities | 0 |
| Injuries | 0 |
Costs
| Property Damage | $79,507 |
| Emergency Response | $0 |
| Other Costs | $0 |
Location Map
Incident Narrative
LEAK DISCOVERED DURING ROUTINE FACILITY CHECKS BY EMPLOYEES OF OPERATOR AND EMPLOYEES OF ANOTHER OPERATOR WITH FACILITIES AT SAME LOCATION. POTENTIAL LIKELY CAUSATIONS (INCLUDING FAILURES IN VALVE BODY BLEED OR GREASE/SEALANT LINE EXTENSION PIPING) INVESTIGATED, BUT COULD NOT BE CONFIRMED. DECISION MADE TO ISOLATE AND REDUCE PRESSURE IN PIPELINE SEGMENT TO ALLOW FURTHER INVESTIGATION. AFTER ISOLATING 2 ADJACENT VALVE SECTIONS AND REDUCING PRESSURE THOUGH FLOW TO LOWER PRESSURE SYSTEM, IMPACTED SEGMENT FURTHER ISOLATED AND REMAINING GAS VENTED TO ATMOSPHERE. IMPACTED SEGMENT WAS PURGED (GAS TO AIR) USING AIR MOVERS IN ANTICIPATION OF NECESSITY TO PERFORM WELDING OPERATIONS TO COMPLETE REPAIRS. INVESTIGATION THROUGH EXCAVATION REVEALED CRACK IN 2 INCH FILLET WELD AT SOCKET WELDED CONNECTION INSTALLED IN 2007 AS FACILITY MODIFICATION TO ALLOW LIQUID REMOVAL FROM LOW POINT IN A NON-PIGGABLE SECTION OF STATION PIPING. ICE FROM FREEZING OF GROUND WATER IN VICINITY OF LEAK (DUE TO COOLING OF GAS AS A RESULT OF PRESSURE REDUCTION) IMPACTED ADJACENT 2 INCH PIPING (NOT RELATED TO SIPHON), PROMPTING REPAIRS TO ADJACENT (NONLEAKING) 2 INCH PIPING IN ADDITION TO PIPING AT LOCATION OF LEAK. AFTER REPAIRS WERE COMPLETED AND NONDESTRUCTIVE INSPECTIONS COMPLETED, LINE SEGMENT WAS PURGED (AIR TO GAS), PRESSURIZED AND RETURNED TO NORMAL OPERATION.
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.