WILLIAMS FIELD SERVICES

Incident Narrative

"ON MARCH 8TH AT ROUGHLY 1924 AN INCREASE IN BUILDING LEL WAS OBSERVED BY PIPELINE CONTROL. AS A RESPONSE TO THE RISING LEL PERCENTAGE, PIPELINE CONTROL SHUTDOWN STATION REMOTELY AND SHORTLY AFTER REMOTELY EMERGENCY SHUTDOWN THE STATION TO COMBAT THE RISING LEL PERCENTAGE IN THE COMPRESSOR BUILDING. FOLLOWING THE COMMAND FROM PIPELINE CONTROL THE DISCHARGE ESD BLOCK VALVE FAILED TO CLOSE. OPERATIONS RESPONDED TO INCIDENT AND FOUND AIR PRESSURE HAD NOT ALLEVIATED FROM DISCHARGE ESD BLOCK VALVE AS DESIGNED, WHICH HELD THE VALVE IN THE OPEN POSITION. OPERATIONS COMPLETED TROUBLESHOOTING ON DISCHARGE ESD BLOCK VALVE AND BELIEVED TO HAVE BLOCK VALVE CLOSED WHICH OPENED ESD VENT VALVES. IT WAS THEN DETERMINED THAT DISCHARGE ESD BLOCK VALVE HAD NOT CLOSED ENTIRELY SO PRESSURE CONTINUED TO BE ALLEVIATED BY ESD VENT VALVES UNTIL OPERATORS WERE ABLE TO MANIPULATE VALVES IN THE FIELD COMPLETELY ISOLATING THE SYSTEM. THIS ALLOWED FOR STATION TO DEPRESSURIZE AS PLANNED AND COMPRESSOR BUILDING LEL ISSUE TO BE LOOKED INTO FURTHER. FINDING WAS A BROKEN SITE GLASS PIPE NIPPLE ON UNIT 4 SCRUBBER BOTTLE. WILLIAMS OPERATIONS AND I&E PERSONNEL COMPLETED TROUBLESHOOTING ON DISCHARGE ESD BLOCK VALVE AND FOUND THAT VERSA VALVE ON INSTRUMENT AIR SYSTEM WAS OPERATING SPORADICALLY. VERSA VALVE ASSOCIATED WITH DISCHARGE ESD BLOCK VALVE WAS REPLACED WITH NEW BEFORE BRING STATION BACK INTO NORMAL OPERATIONS. FULL SYSTEM TEST WAS COMPLETED ON THURSDAY MARCH 13TH TO ENSURE THINGS WERE FUNCTIONING AS INTENDED. FURTHER INVESTIGATION IS ONGOING."