TENNESSEE GAS PIPELINE COMPANY

Incident Narrative

NRC #1260273; NRC #1260341 (48-HOUR); 36-INCH TENNESSEE GAS PIPELINE COMPANY, L.L.C. (TGP); LINE 200-4 WITH HOT TAP RECEIVING NATURAL GAS FROM TALLGRASS BIG MUSKINGUM METER STATION: AT 15:45-HOURS, THE LANDOWNER OBSERVED DIRT BLOWING AT THE HOT TAP RISER AND NOTIFIED A GRANDSON WHO NOTIFIED HIS BROTHER, A TGP COMPANY EMPLOYEE. AT 15:57-HOURS, EMPLOYEE ARRIVED ON SITE AND CONFIRMED A LEAK AT THE HOT TAP RISER. AT 16:15-HOURS, ALTHOUGH THE LANDOWNER'S HOME WAS OUTSIDE OF THE PIR (MORE THAN 1,900 FEET FROM THE LEAK SITE) THE LANDOWNER'S GRANDSON CHOSE TO RELOCATE THE LANDOWNER TO A RELATIVE'S HOME. THE DOWNSTREAM AND THE UPSTREAM PIPELINE MAIN LINE VALVES WERE CLOSED AT 17:15-HOURS. FOLLOWING NOTIFICATION TO APPLICABLE EMERGENCY RESPONDERS, AT 19:22-HOURS, BLOW-DOWN OF THE PIPELINE VALVE SECTION BEGAN. ON OCTOBER 5, 2019, AT 00:05-HOUR, BLOW-DOWN OF THE VALVE SECTION WAS COMPLETE. EXCAVATION AT THE HOT TAP SITE FOUND THE NECK OF THE HOT TAP FITTING CONTAINED A CRACK. THE HOT TAP WAS CUT OUT OF THE PIPELINE AND THE PIPELINE WAS REPAIRED WITH REPLACEMENT PIPE. DUE TO CHANGES IN BUSINESS NEEDS, THE HOT TAP CONNECTION WILL NOT BE REPLACED. THE HOT TAP FITTING WENT THROUGH LABORATORY ANALYSIS FOR CAUSE OF THE NECK FILLET WELD CRACK. THE JANUARY 17, 2020 METALLURGICAL REPORT CONCLUDES THE HOT TAP NECK FILLET WELD CRACK OCCURRED FROM FATIGUE. SAID REPORT FINDS FATIGUE CAUSE WAS STRESS AND / OR VIBRATION FROM PULSATION OF THE COMPONENT AND INSUFFICIENT SUPPORT OF A NEARBY BLOW OFF VALVE ASSEMBLY. NO MATERIAL DEFICIENCIES WERE FOUND WHICH WOULD HAVE CONTRIBUTED TO THE COMPONENT FAILURE.