ANR PIPELINE CO

Incident Narrative

ON JUNE 30 AT 08:58 CDT, ANR PIPELINE'S GAS CONTROL RECEIVED AN EMERGENCY SHUTDOWN SYSTEM (ESD) FIRE ALARM AT EUNICE COMPRESSOR STATION LOCATED AT 4202 FOURNERAT ROAD, EUNICE, LA 70535 (30.465980, - 92.522270). WHEN THE ALARM WAS DETECTED, A TECHNICIAN WAS DISPATCHED TO THE COMPRESSOR STATION TO INVESTIGATE. UPON ARRIVAL AT THE SITE AT 09:35 CDT, THE TECHNICIAN DISCOVERED NATURAL GAS BEING RELEASED TO THE ATMOSPHERE THROUGH THE VENT STACKS. IMMEDIATE ACTION WAS TAKEN BY VERIFYING NO FIRE EXISTED AND CLOSING THE VALVES OPEN TO ATMOSPHERE, WHICH ENDED THE RELEASE AT 09:43 CDT. UNINTENTIONAL GAS LOSS WAS CALCULATED TO 99 MILLION CUBIC FEET (MMCF). NO PROPERTY DAMAGE OR INJURIES WERE DOCUMENTED, AND NO MANDATORY EVACUATIONS WERE REQUIRED. THE CAUSE OF THE UNINTENTIONAL RELEASE HAS BEEN ATTRIBUTED TO A FLAME DETECTION EQUIPMENT (FIRE EYE) ACTIVATION THAT INITIATED THE EMERGENCY SHUTDOWN (ESD) SYSTEM. WHEN THE SYSTEM INITIATED, SEVEN ESD VALVES DID NOT FULLY OPERATE ALLOWING GAS TO CONTINUE TO VENT UNTIL PERSONNEL ARRIVED ON SITE AND ISOLATED THE SYSTEM. NO INDICATION OF FIRE WAS OBSERVED IN THE COMPRESSOR BUILDING. THE FLAME DETECTOR UNIT WAS SENT TO THE ORIGINAL MANUFACTURER FOR EVALUATION. THE MANUFACTURER REPORTED THAT THE DETECTION UNIT MET ALL MANUFACTURING SPECIFICATIONS AND OPERATED AS INTENDED. THE MANUFACTURER ALSO RECOMMENDED THAT THE UNIT'S SENSITIVITY BE REDUCED FROM ""HIGH"" TO ""MEDIUM"" AND INCREASE THE ACTIVATION DELAY FROM 8 SECONDS TO 10 SECONDS. THESE RECOMMENDED CHANGES ARE DUE TO THE OPERATIONAL AND ENVIRONMENTAL CONDITION IN THE RECIPROCATING ENGINE COMPRESSOR BUILDING. THE CHANGE IN SENSITIVITY AND TIMING DOES NOT AFFECT THE SAFETY OF THE PIPELINE FACILITY AND THE SYSTEM HAS BEEN TESTED ACCORDING TO PROCEDURES. THE CHANGES TO THE FLAME DETECTION EQUIPMENT WAS COMPLETED ON 26 JULY 2019. INVESTIGATION INTO ESD VALVES DETERMINED THAT PILOT GAS WAS NOT VENTED COMPLETELY UPON AUTOMATIC ACTIVATION. EVEN THOUGH THE ESD SYSTEM HAD ACTIVATED AND STARTED TO VENT PILOT GAS, PRESSURES THROUGH THE SUPPLY LINE MAINTAINED ENOUGH PRESSURE TO PREVENT THE VALVES FROM FULLY MOVING TO THE CLOSED POSITION. TO REDUCE THE PILOT GAS SUPPLY, A SMALLER 1/32"" ORIFICE PLATE WAS INSTALLED INTO THE SUPPLY LINE ON AUGUST 14, 2019, REDUCING THE FLOW OF GAS AND RECHARGE TIME INTO THE SUPPLY SYSTEM. THE PURPOSE OF THE ORIFICE IS TO MAINTAIN PILOT GAS PRESSURE IN THE EVENT OF A MINOR LEAK TO PREVENT AN UNINTENDED ESD. THE ESD SYSTEM HAS BEEN INSPECTED AND TESTED ACCORDING TO PROCEDURES SINCE THE ORIFICE REPLACEMENT AND OPERATED CORRECTLY. THE SYSTEM HAS BEEN PLACED BACK INTO FULL SERVICE. IN ADDITION TO THE ORIFICE CHANGE, FIVE EMERGENCY VALVES WILL BE UPGRADED WITH NEW THREE-WAY PILOT VALVE ASSEMBLIES AND THE END-OF-STROKE VALVE ON TWO OTHER VALVES WILL BE REPLACED, WHICH WILL ENSURE PROPER OPERATION OF THE VALVES. THE ADDITIONAL UPGRADES TO THE VALVES ARE ANTICIPATED TO BE COMPLETED WITHIN 120 DAYS.