SUPERIOR UTILITIES, CITY OF

Incident Narrative

THIS IS A CONDENSED SUMMARY OF THE EVENTS. THIS NARRATIVE WILL TRUNCATE DUE TO SPACE CONSIDERATIONS. FOR THE FULL REPORT, SEE THE COMPLETE ATTACHMENT SUBMITTED ORIGINALLY. ON JULY 11, 2011 OPERATIONS WERE BEGAN TO ABANDON A SEGMENT OF 6' PIPING, OPERATING AT 18 OUNCES OF PRESSURE, FROM WITHIN THE SYSTEM. AN INFLATABLE BAG WAS INSERTED INTO THE 6' MAIN AND INFLATED TO STOP GAS FLOW TO DOWNSTREAM PIPING. THE DOWNSTREAM PIPING WAS PURGED OF GAS AND GAS FLOW WAS CONFIRMED STOPPED AT 10:25 AM. A SEGMENT OF PIPING WAS REMOVED DOWNSTREAM OF THE STOP POINT AND PREPARATION BEGAN TO SEAL THE END OF PIPE. AT APPROXIMATELY 12:20 PM. THERE WAS A FAILURE OF THE INFLATABLE LINE STOPPER, A RELEASE OF NATURAL GAS AND INSTANTANEOUS IGNITION OF THAT NATURAL GAS. UPON IGNITION, THE GAS DEPARTMENT EMPLOYEE SAFELY EXITED THE EXCAVATION AS A SECOND EMPLOYEE ATTEMPTED TO EXTINGUISH THE FIRE. EMERGENCY OPERATIONS BEGAN AND GAS FLOW WAS STOPPED AND 6' PIPING SEALED BY 3:00 PM. THIS RELEASE OF NATURAL GAS AND SUBSEQUENT FIRE DAMAGED EXCAVATOR EQUIPMENT AND LOCAL UTILITY FACILITIES IN THE AREA. THIS FIRE NECESSITATED THE SHUTDOWN OF PART OF THE ELECTRICAL POWER SYSTEM.