SOUTHERN NATURAL GAS CO
gas_transmission Incident — — January 6, 2010
Incident Information
| Incident Date | January 6, 2010 |
| Operator | SOUTHERN NATURAL GAS CO |
| Commodity | NATURAL GAS |
| Pipeline Type | gas_transmission |
Location
| State | |
| Coordinates | 33.10762, -89.15281 |
Cause
| Cause | CORROSION FAILURE |
| Subcause | EXTERNAL CORROSION |
Casualties
| Fatalities | 0 |
| Injuries | 0 |
Costs
| Property Damage | $140,000 |
| Emergency Response | $20,000 |
| Other Costs | — |
Location Map
Incident Narrative
ON JANUARY 6 2010 SOUTHERN NATURAL GAS (SNG) COMPANY OPERATIONS PERSONNEL AT THE LOUISVILLE (MS) COMPRESSOR STATION ADVISED SNG GAS CONTROL THAT MEMBERS OF THE GENERAL PUBLIC HAD REPORTED A LOUD NOISE NEAR HIGHWAY 14 WEST OF LOUISVILLE MS. GAS CONTROL SAW A CORRESPONDING PRESSURE DROP VIA THE SCADA SYSTEM. A FAILURE HAD OCCURED ON SNG'S 24 INCH 2ND NORTH MAIN PIPELINE. SNG FIELD PERSONNEL WERE DISPATCHED TO CLOSE VALVES FOR ISOLATION OF THE FAILURE SITE AND TAKE THE AFFECTED SEGMENT OF PIPELINE OUT OF SERVICE. THE FAILURE WAS CAUSED BY A CLUSTER OF EXTERNAL CORROSION PITS WITH SUBSEQUENT NEAR-NEUTRAL PH STRESS CORROSION CRACKING (SCC) CONFINED WITHIN A LOCALIZED AREA OF THE MOST SEVERE CORROSION. THE EVIDENCE GATHERED DURING THE INVESTIGATION CONCLUDED THAT THE EXTERNAL CORROSION WHICH INITIATED THIS FAILURE ALLOWED ELECTROCHEMICAL CORROSION TO THIN THE PIPE WALL, INCREASING THE LOCALIZED STRESSES, WHICH CROSSED THE THRESHOLD FOR SCC TO INITIATE AND PROPAGATE UNTIL THE REMAINING PIPE WALL COULD NO LONGER SUPPORT NORMAL OPERATING PRESSURE.
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.