ONEOK NGL PIPELINE, LLC

Incident Narrative

PIPELINE CONTROL CENTER RECEIVED A GAS DETECT AND STATION SHUTDOWN AT 14:30 ON 11/30/2014 FOR ONEOK'S VELMA PUMP STATION. AREA REP WAS CALLED AND ARRIVED AT STATION AT 14:50 AND DISCOVERED COOLING LINE TUBING ON PUMP #3 AND COME APART. PUMP WAS ISOLATED AND LOCKED OUT. STATION ALARMS WERE RESET AND STATION RESTARTED AT 15:00. INVESTIGATION DETERMINED POSSIBLE INADEQUATE SUPPORT OF 3/8"" OUTBOARD SEAL COOLING LINE. ONEOK EMPLOYEE REPLACED THE TUBING AND INSTALLED ADDITIONAL SUPPORT. ONEOK HAS RETRAINED ALL INSTRUMENTATION TECHNICIANS IN THE MANUFACTURES PROCEDURES FOR TUBING FITTING INSTALLATION. (PARKER MANUFACTURING) 6/02/2015 -- UPDATE UPDATED PART G -- APPARENT CAUSE TO G7 -- INCORRECT OPERATION FAILED TUBING AND FITTING WERE SENT TO ""INDUSTRIAL INSPECTION & CONSULTING"" (I2C) FOR EVALUATION. ON MARCH 17, 2015 I2C SUBMITTED TO ONEOK THEIR REPORT WITH THE FOLLOWING FINDINGS, ""... TUBE FAILED AS A RESULT OF LOW STRESS-HIGH CYCLE FATIGUE, AS INDICATED BY FRACTURE'S FLAT AND PERPENDICULAR PROFILE AND PRESENCE OF BEACH AND RATCHET MARKS. FATIGUE FAILURE WAS PRECIPITATED BY CONDITIONS CAUSED BY OVERTIGHTENING OF COMPRESSION FITTING, AS INDICATED BY DEFORMATION OF OUTER SURFACE OF TUBE AND BULGING OF PARTED TUBE SECTION THAT WAS BROKEN OFF IN MALE TO MALE FITTING. AS EXPLAINED IN DISCUSSION SECTION OF THIS REPORT, FATIGUE IS A MODE OF FAILURE THAT IS CAUSED BY CYCLICAL STRESSES, EITHER CAUSED BY FLUCTUATING LOAD OR VIBRATION WHOSE AMPLITUDE IS LESS THAN YIELD STRENGTH OF MATERIAL. ..."" ONEOK TECHNICIANS RECEIVED INTIAL TRAINING IN THE INSTALLATION OF STAINLESS STEEL TUBING PRIOR TO THE FAILURE AND ALL TECHNICIANS HAVE BEEN RETAINED BY THE MANUFACTURE (PARKER MANUFACTURING) SINCE THE FAILURE.