NORTHERN NATURAL GAS CO

gas_transmission Incident —

Incident Information

Report Date
OperatorNORTHERN NATURAL GAS CO
Commodity—
Pipeline Typegas_transmission

Location

State
Coordinates41.53886, -96.53639

Cause

CauseMATERIAL FAILURE OF PIPE OR WELD
Subcause—

Casualties

Fatalities0
Injuries0

Costs

Property Damage
Lost Commodity
Public/Private Damage
Emergency Response
Environmental Remediation
Other Costs

Location Map

Incident Narrative

AT 8:30 AM ON MARCH 14, 2014 THE PALMYRA TO HOOPER B-LINE, ALSO KNOWN AS NEM50102-M581B, RUPTURED AND CAUGHT FIRE. THE RUPTURE INITIATED NEAR A 12-INCH TIE-OVER LINE BETWEEN THE 1ST LINE (A-LINE) AND THE SECOND LINE (B-LINE). THE RUPTURE AND FIRE DAMAGED TWO MAINLINE VALVE SETTINGS AND A BRANCH LINE TAKE-OFF. THREE HOMES WERE EVACUATED BY THE THE LOCAL EMERGENCY RESPONDERS BUT HOMEOWNERS WERE ALLOWED TO RETURN LATER IN THE DAY. AT THIS TIME, THE CAUSE HAS NOT BEEN DETERMINED. THE PIPE FAILURE PIECE WAS SENT TO STRESS ENGINEERING IN HOUSTON FOR TESTING. METALLURGICAL ANALYSIS COULD NOT PRECISELY DETERMINE THE ROOT CAUSE OF THE RUPTURE. IT IS BELIEVED THAT INTERACTING DEFECTS FROM ORIGINAL CONSTRUCTION WITH SOME GROUND MOVEMENT MAY HAVE CAUSED A CRACK IN THE FILLET WELD OF A REINFORCING SADDLE TO FAIL. COST UPDATE INFORMATION: NORTHERN'S EMERGENCY RESPONSE WAS ACTUALLY ON THE ORDER OF ABOUT $200,000. HOWEVER, WHEN WE BEGAN TO REMOVE 2 MAINLINE BLOCK VALVE SETTINGS AND PIPE, 4 CROSSOVERS AND THEIR VALVES, REBUILT THE BLAIR LOOP (CARGILL) BRANCHLINE TAKE-OFF, REROUTED ABOUT 600 FEET OF 6-INCH PIPE ALL WHILE MAINTAINING SERVICE TO BLACK HILLS ENERGY. OUR CONTRACTOR WAS ON THIS PROJECT FOR NEARLY ONE MONTH.

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.

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