ENABLE MISSISSIPPI RIVER TRANSMISSION, LLC

Incident Narrative

11/14/19, 13:00 EMRT'S WESTLINE EXPERIENCED A FAILURE IN UNION PARISH LOUISIANA. THE FAILURE OCCURRED NEAR THE GIRTH WELD AREA OF A REPAIRED SECTION OF PIPE. THE PIPE WAS INSTALLED THE PREVIOUS DAY TO REMOVE AN ANOMALY DISCOVERED BY AN ILI TOOL RUN. THE FAILED SECTION WAS REMOVED AND SENT TO PRECISION ENGINEERING FOR ANALYSIS. NRC INITIAL 11/14/2019 (NRC # 1263945). 48 HR FOLLOW UP 1/15/2019 (NRC# 1264007). 07.10.2020 SUPPLEMENTAL. PRECISION ENGINEERING SOLUTIONS, LLC WAS CONTRACTED TO PERFORM A FAILURE INVESTIGATION FOR ENABLE ON CRACKING AND LEAKING ASSOCIATED WITH A GIRTH WELD IN THE WESTLINE SYSTEM THAT JOINED TWO PIPE MATERIALS: 18"" .281"" (OLD PIPE) AND 18"" .375"" (NEW PIPE). THE OLD PIPE WAS INSTALLED IN 1950, WHILE THE NEW PIPE WAS INSTALLED IN 2019. THE DIMENSIONAL EXAMINATION SHOWED THAT THE PIPE ON EITHER SIDE OF THE GIRTH WELD MET THE DIMENSIONAL REQUIREMENTS OF THE APPLICABLE API 5L AND 5LX SPECIFICATIONS FOR THEIR RESPECTIVE DATES OF MANUFACTURE AND SIZES. THE CHEMICAL ANALYSIS SHOWED THAT THE NEW PIPE MET THE CHEMICAL COMPOSITION REQUIREMENTS API 5L, BUT THAT THE OLD PIPE DID NOT, DUE TO HIGH CARBON, PHOSPHOROUS, AND CARBON EQUIVALENCY. IT IS TO BE NOTED THAT THERE WERE NO CHEMICAL COMPOSITION REQUIREMENTS FOR X52 LINE PIPE AT THE TIME OF THE MANUFACTURE OF THE OLD PIPE (1950). THE HARDNESS TESTING CONDUCTED DID NOT SHOW ANY ABNORMALITIES IN THE HARDNESS OF THE PIPES, HEAT AFFECTED ZONES, OR WELD METAL. THE MAGNETIC PARTICLE INSPECTION OF THE I.D. SURFACE SHOWED CRACK INDICATIONS ON THE OLD PIPE SIDE OF THE GIRTH WELD AROUND THE ENTIRE CIRCUMFERENCE. THE MICROSCOPIC EXAMINATION SHOWED LACK OF FUSION ORIGINATING AT THE I.D. BETWEEN THE OLD PIPE AND THE ROOT PASS WELD METAL. DUCTILE OVERLOAD FRACTURE WAS FOUND NEAR THE O.D. AND THROUGH-WALL IN SOME REGIONS. A VISUAL EXAMINATION OF THE FRACTURE SURFACE OF THE THROUGH WALL CRACK SHOWED LACK OF FUSION PRESENT AROUND MOST OF THE I.D. SURFACE WITH THE REMAINDER OF THE FRACTURE SURFACE BEING DUCTILE OVERLOAD. THE LACK OF FUSION IS THOUGHT TO BE ASSOCIATED WITH WELDING PARAMETERS AND WELDING TECHNIQUE. ALTHOUGH THE CARBON CONTENT AND CARBON EQUIVALENCE OF THE OLD PIPE WAS HIGH AND IN EXCESS OF CURRENT API 5L REQUIREMENTS, IT IS NOT THOUGHT TO BE THE PRIMARY CAUSE OF THE FAILURE. ADDITIONALLY, THE PRESENCE OF ELEVATED STRESSES GENERATED DURING THE TIE-IN PROCESS CANNOT BE DISCOUNTED, ALTHOUGH IT IS DIFFICULT TO QUANTIFY WHAT MAGNITUDE OF STRESS MIGHT HAVE EXISTED AT THE TIME OF CONSTRUCTION. ALL TIE IN WELDS ON THE WESTLINE REMEDIATION PROJECT WERE NON-DESTRUCTIVELY TESTED WHEN COMPLETED. WELDS TI-9 AND TI-10 (NEW PIPE) WERE TESTED AND PASSED BY A LEVEL II TECHNICIAN. THE TECHNICIAN'S PAPERWORK STATED THEY WERE FOLLOWING THE MINIMUM GUIDELINES SET FORTH IN API 1104. AFTER THE INCIDENT, THE X-RAY FILM FOR TI-9 AND TI-10 WAS SENT TO A 3RD PARTY X-RAY COMPANY FOR A QUALITY CONTROL CHECK. THE 3RD PARTY FOUND THE FILM DENSITY TO BE LESS THAN THE REQUIRED RANGE OF 1.8 - 4.0 THAT API 1104 AND ENABLE MIDSTREAM CONSTRUCTION SPEC CS-095 REQUIRE. FIVE OF THE SIX X-RAY SHOTS FOR TI-9 AND TI-10 WERE BELOW THE MINIMUM DENSITY REQUIREMENT OF 1.8. DENSITY BELOW 1.8 COULD POSSIBLY CAMOUFLAGE A FEATURE, IF PRESENT. DUE TO FILM DENSITY BEING OUT OF SPEC, ENABLE DISQUALIFIED THE X-RAY TECH. 7/30/20 SUPPLEMENTAL. BOTH WELDERS THAT PERFORMED THE WELDS WERE QUALIFIED AT THE TIME OF THE TIE-IN. BOTH HAD BEEN OBSERVED FOLLOWING THE WELDING PROCEDURE PRIOR TO THE FAILURE. AFTER THE FAILURE, A WELDER REVIEW WAS CONDUCTED AND THEY WERE NOT DISQUALIFIED. OF THE THREE X-RAY REVIEWS AFTER THE INCIDENT, ONLY ONE WELD WAS FOUND TO BE OUT OF SPEC (TI-10) FOR WHICH IT WAS REPAIRED IMMEDIATELY, X-RAYED, AND FOUND PASSING. WELD TESTING WAS PERFORMED AND CONFIRMED THE WELDING PROC. USED WAS ADEQUATE. ALONG WITH WELD TESTING, AND LEVEL III TECH REVIEWS, ENABLE WILL PERFORM AN ASSESSMENT APPROPRIATE FOR CRACK-LIKE DEFECTS ON THE WESTLINE HCAS, MCAS AND CLASS 3 LOCATIONS DURING THE NEXT REASSESSMENT CYCLE.