WBI ENERGY TRANSMISSION, INC.

Incident Narrative

***SUPPLEMENTAL REPORT*** UNIFIED INVESTIGATIONS & SCIENCES, INC. (UIS) WAS CONTRACTED TO DIRECT AND COMPLETE AN INVESTIGATION ON THE GAS FIRED HEATER INCIDENT THAT OCCURRED ON 2/28/14. UIS COORDINATED THE REMOVAL OF THE FAILED SECTION OF PIPING FROM THE GAS FIRED HEATER ON 4/1/14. AN INTACT EXEMPLAR PIPE SECTION FROM A LOWER ELEVATION WITHIN THE GAS FIRED HEATER WAS ALSO REMOVED AT THE SAME TIME TO BE ANALYZED WITH THE FAILED SECTION. THE SAMPLES WERE SENT TO FORENSIC CONSULTANTS GROUP, LLC (FCG) IN DENVER, CO TO EVALUATE THE FAILED PIPE SECTION AND TO DETERMINE WHETHER OR NOT MATERIAL SELECTION, PRE-EXISTING DAMAGE, USER ERROR, OPERATING CONDITIONS, AND/OR DESIGN/MANUFACTURING DEFECTS CAUSED OR CONTRIBUTED TO THE OBSERVED FAILURE. FCG FINDING: - THE ""FISHMOUTH"" TYPE RUPTURE IN THE SPOOL PIECE SHOWED EXTENSIVE DEFORMATION AND THINNING TYPICAL OF A RELATIVELY SHORT-TERM OVERHEAT FAILURE. - EXTENSIVE SECONDARY CRACKING WAS NOTED IN BOTH THE CIRCUMFERENTIAL WELDS ON EITHER SIDE OF THE SPOOL PIECE AND IN THE SPOOL PIECE MATERIAL ITSELF. THE PRESENCE OF THE EXTENSIVE SECONDARY CRACKING ALONG WITH THE CRACKING THAT LED TO THE FAILURE SHOWS THAT THE FAILURE WAS DUE TO A UNIFORM CONDITION IN THE PIPING SUCH AS EXCESSIVE TEMPERATURE, PRESSURE, OR INADEQUATE WALL THICKNESS RATHER THAN AN ISOLATED DEFECT. - THE ULTIMATE FAILURE OF THE SPOOL PIECE WAS CAUSED BY ELEVATED-TEMPERATURE THINNING OF THE TUBE WALL AND THE INITIATION AND GROWTH OF CREEP CRACKS TO THE POINT WHERE THE REMAINING CROSS SECTION COULD NO LONGER SUPPORT THE INTERNAL GAS PRESSURE. - THE RESULTS OF THE OPTICAL EMISSION SPECTROSCOPY (OES) OF THE MATERIAL SHOWED THAT THE CHEMICAL COMPOSITION WAS WITHIN THE REQUIREMENTS FOR THE SA106 GRADE B MATERIAL. - THE RESULTS OF THE TENSILE TESTS INDICATE THAT THE SPOOL PIECE AND THE ADJACENT PIPING MATERIAL MET THE MECHANICAL PROPERTY REQUIREMENTS OF SA106 GRADE B MATERIAL. WBI HAS ANALYZED THE FINDINGS IN THE FCG REPORT AND HAVE INITIATED TAKING SEVERAL STEPS TO PREVENT THIS INCIDENT FROM HAPPENING AGAIN ON THE REPLACEMENT UNIT AND ON EXISTING UNITS. DURING THE INSTALLATION OF THE NEW GAS FIRED HEATER, WBI WILL REQUIRE THE MANUFACTURE OF THE GAS FIRED HEATER TO BE ONSITE FOR THE STARTUP/COMMISSIONING AND VERIFICATION OF ALL LOGIC, SYSTEM INTERLOCKS, AND SHUTDOWNS. ADDITIONAL SHUTDOWNS WILL BE ADDED TO THE LOGIC INCLUDING A SHUTDOWN REQUIRING THE REGEN COMPRESSOR TO BE IN A RUN STATE FOR THE GAS FIRED HEATER TO BE IN OPERATION AND A SECONDARY DIFFERENTIAL PRESSURE SHUTDOWN DEVICE WILL BE ADDED TO MEASURE FLOW GOING INTO THE GAS FIRED HEATER AND SHUTDOWN ON LOW FLOW CONDITIONS. IN ADDITION TO THE STEPS WBI WILL TAKE ON THE REPLACEMENT GAS FIRED HEATER UNIT, WBI WILL ALSO TAKE ADDITIONAL STEPS WITH OUR EXISTING UNITS TO CONFIRM THEY ARE IN SATISFACTORY OPERATIONAL CONDITION. PRIOR TO THE END OF 2014 WBI WILL: - DEVELOP A PLAN TO VERIFY THE INTEGRITY OF THE TUBING BUNDLES TO IDENTIFY AREAS OF TUBE SWELLING AND CRACKING AND FULLY IMPLEMENT THIS PLAN WITHIN 12 MONTHS, - ESTABLISH CRITERIA AND VERIFY THAT SYSTEM SHUTDOWNS OCCUR QUICKLY ENOUGH TO PREVENT ANY DAMAGE FROM OCCURRING IN THE CASE OF A UNIT MALFUNCTION, AND - INSPECT AND CALIBRATE ALL GAS FIRED HEATER EQUIPMENT. WBI WILL STANDARDIZE THE INSPECTION AND CALIBRATION FORM AND REQUIRE THAT ALL STATIONS INSPECT AND CALIBRATE ALL GAS FIRED HEATER EQUIPMENT ANNUALLY; AND WBI WILL IMPLEMENT THE DEVELOPED INSPECTION PLAN OF THE TUBING BUNDLES TO BE DONE EVERY THREE YEARS. WBI FEELS IMPLEMENTING THE ABOVE DESCRIBED PROCESSES IS A PRUDENT APPROACH TO MITIGATING SAFETY CONCERNS ASSOCIATED WITH THIS INCIDENT.