SOUTHERN NATURAL GAS CO
gas_transmission Incident — — February 18, 2011
Incident Information
| Incident Date | February 18, 2011 |
| Operator | SOUTHERN NATURAL GAS CO |
| Commodity | NATURAL GAS |
| Pipeline Type | gas_transmission |
Location
| State | |
| Coordinates | 33.62976, -85.51169 |
Cause
| Cause | MATERIAL FAILURE OF PIPE OR WELD |
| Subcause | DESIGN-, CONSTRUCTION-, INSTALLATION-, OR FABRICATION-RELATED |
Casualties
| Fatalities | 0 |
| Injuries | 0 |
Costs
| Property Damage | $126,000 |
| Emergency Response | $5,000 |
| Other Costs | $30,000 |
Location Map
Incident Narrative
SOUTHERN NATURAL GAS (SNG) COMPANY'S GAS CONTROL NOTICED A PRESSURE DROP IN ITS SCADA SYSTEM ON FEBRUARY 18, 2011 THAT INDICATED A POSSIBLE PIPELINE LEAK. FIELD PERSONNEL WERE DISPATCHED TO INVESTIGATE THE 24"" NORTH MAIN LOOP PIPELINE. A CRACK IN A WRINKLE BEND WAS FOUND AT MILEPOST 396.6 RELEASING NATURAL GAS. THE PIPELINE WAS ALREADY ISOLATED DUE TO CAO CPF 2-2010-1001H, CONTAINING GAS BETWEEN THE CLOSED VALVES AT A PRESSURE OF 290 PSIG. THE LINE WAS BLOWN DOWN WITH A 135 FEET SECTION CUT OUT, WELD CAPS BEING INSTALLED ON EITHER SIDE OF THE CUT. THE LINE SEGMENT IS OUT OF SERVICE AND WILL REMAIN SO UNTIL 2012 WHEN IT IS PLANNED FOR ABANDONMENT. THE POST-INCIDENT INVESTIGATION AND EVALUATIONS REVEALED FAILURE LIKELY TO HAVE BEEN CAUSED BY COMBINED MECHANICAL STRESSES IN A WRINKLE BEND, WITH SUCH STRESSES COMING FROM NORMAL PIPELINE OPERATIONS, HYDROGEOLOGICAL INFLUENCE IN THE SOIL, AND THE NATURE OF WRINKLE BEND CONFIGURATION.
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.