COLUMBIA GAS TRANSMISSION CORP

Incident Narrative

AT APPROXIMATELY 12:30 AM ON THURSDAY, NOVEMBER 3, 2011, A NEIGHBOR OF THE ARTEMAS COMPRESSOR STATION CALLED THE LOCAL COLUMBIA GAS TRANSMISSION MAINTENANCE MECHANIC TO REPORT AN INCIDENT AND FIRE AT THE STATION. THAT EMPLOYEE CONTACTED A SECOND COMPANY EMPLOYEE FOR ASSISTANCE AT THE STATION. THE NGT&S MONITORING CENTER WAS ALSO CONTACTED TO INFORM THEM OF THE POSSIBLE INCIDENT. UPON CONFIRMING THE FIRE AND INITIATING AN ESD OF THE STATION, THE AREA WAS SECURED. COMPANY PERSONNEL WORKED WITH THE LOCAL FIRE DEPARTMENT TO ENSURE THE SAFETY OF THE PUBLIC AND THE AREA. IT WAS FOUND THAT THE DUMP VALVE FOR THE ARTEMAS B FIELD SLUG CATCHER HAD FAILED IN THE OPEN POSITION. UPON CLOSING THIS VALVE, THE FIRE WAS FULLY EXTINGUISHED. THE RESULTS OF THE ANALYSIS BY A THIRD PARTY EXPERT IN METALLURGY AND FAILURE ANALYSIS INDICATED THAT THE RUPTURE WAS LIKELY DUE TO WATER FREEZING IN THE DRAIN LINE. THE FROZEN LIQUID CAUSED THE PIPING TO EXPAND, PRODUCING DUCTILE TEARING AT INTERNAL CORROSION FEATURES. THE RESULTANT FLAW SIZE WAS CRITICAL FOR THE MATERIAL PROPERTIES, DIMENSIONS, AND OPERATING PRESSURE OF THE PIPING. FREEZING OCCURRED SOMETIME PRIOR TO THE FAILURE. THE PRESENCE OF THE INTERNAL CORROSION WAS A CONTRIBUTING FACTOR TO THE FAILURE. THE COMPANY HAS DEVELOPED AN INTEGRITY PLAN COVERING PRESSURIZED LIQUID/DUMP PIPING FROM VESSELS AT ITS ACTIVE COMPRESSOR STATIONS. THE PLAN SUMMARIZES IMMEDIATE INITIAL STEPS AS WELL AS LONG TERM STEPS THAT WILL BE TAKEN TO ADDRESS DUMP/DRAIN VALVE PIPING COMPANY-WIDE.