ROCKIES EXPRESS PIPELINE LLC

Incident Narrative

AT APPROXIMATELY 17:56 CST ON JANUARY 29, 2015, A RUPTURE RESULTING IN A NATURAL GAS RELEASE OCCURRED ON THE ROCKIES EXPRESS PIPELINE (REX) NEAR STATE ROAD U AND PIKE COUNTY ROAD 43 (CLASS 1 AREA) IN PIKE COUNTY, MISSOURI. THE 42"" PIPELINE WAS OPERATING AT 1296 PSIG AT THE TIME OF THE INCIDENT, WITH AN ESTABLISHED MAXIMUM ALLOWABLE OPERATING PRESSURE (MAOP) OF 1480 PSIG. THERE WAS NO FIRE, EXPLOSION, INJURY/DEATH, OR MAJOR PRIVATE PROPERTY DAMAGE ASSOCIATED WITH THE RUPTURE. FIFTY FAMILIES WERE EVACUATED BY LOCAL LAW ENFORCEMENT. THE FIRST SCADA SAFETY RELATED LINE BREAK ALARM FOR THE MEXICO COMPRESSOR STATION WAS RECEIVED IN THE OPERATIONAL CONTROL CENTER (OCC) AT 17:56 CST. THE CONTROLLER IMMEDIATELY CONTACTED THE ON-CALL STATION OPERATOR AT MEXICO COMPRESSOR STATION TO DETERMINE IF THERE WAS AN ISSUE AT THE STATION. THE VALVE DOWNSTREAM OF THE RUPTURE SITE (MLV 65) CLOSED IMMEDIATELY UPON SENSING THE PRESSURE DROP. A REPRESENTATIVE OF THE BOWLING GREEN FIRE DEPARTMENT CONTACTED OCC AT 18:15 CST, WHICH WAS FOLLOWED BY A CALL FROM THE PIKE COUNTY SHERIFF AT 18:20 CST TO COMMUNICATE THEIR ARRIVAL ON SITE. AT 18:30 CST THE CONTROLLER SPOKE WITH LOCAL FIELD OPERATIONS PERSONNEL WHO WERE IN ROUTE TO THE SITE. TALLGRASS FIELD OPERATIONS PERSONNEL ARRIVED ON SITE AT 19:40 CST, MET WITH THE LOCAL INCIDENT COMMANDER, AND AT THAT TIME CONFIRMED THE RUPTURE. FIELD OPERATIONS SUPERVISED THE BLOWDOWN OF GAS UNTIL IT WAS SAFE TO APPROACH THE RUPTURE SITE IN PREPARATION FOR THE INCIDENT INVESTIGATION. AT 0:52 CST EMERGENCY RESPONSE ACTIVITIES CONCLUDED AND THE SITE WAS DEEMED SECURE. INCIDENT INVESTIGATION AND CLEAN-UP BEGAN THE MORNING OF JANUARY 30, 2015. THE FIELD INVESTIGATION REVEALED THAT THE FAILURE OCCURRED AT A WELD. INCLUDED ARE BOTH THE UPSTREAM AND DOWNSTREAM PIPE CHARACTERISTICS: - UPSTREAM: X70, WT. 0.74, ARO - DOWNSTREAM: X80, WT. 0.486, FBE - 0.740"" BEVEL WAS PREPARED IN ACCORDANCE WITH ASME B31.8 ANNEX I AND SHOWED EVIDENCE OF GOOD WORKMANSHIP SUBSEQUENT TO THE ROOT CAUSE ANALYSIS DISCUSSION, AND WITH AGREEMENT FROM ALL PARTIES INVOLVED, IT WAS DEEMED THAT THE GIRTH WELD RUPTURE WAS AN OVERLOAD FAILURE CAUSED BY AXIAL STRESS THAT EXCEEDED THE CROSS SECTION TENSILE STRENGTH OF THE CRACK INITIATION LOCATION. THIS DETERMINATION IS SUPPORTED BY CRACK CHARACTERISTICS, METALLURGICAL ANALYSIS, POTENTIAL FAILURE MODES AND OBSERVATION OF THE PIPE GEOMETRY RESULTING FROM THE RUPTURE. THE RCA IDENTIFIED FIVE AXIAL LOAD INDUCING VARIABLES THAT LIKELY LEAD TO THE EXCEEDANCE OF THE CROSS SECTION TENSILE STRENGTH, HOWEVER, NO SINGLE VARIABLE CAN BE BLAMED FOR THE OVERALL CAUSE OF THE RUPTURE. THE FIVE PREDOMINATE AXIAL LOAD INDUCING VARIABLES ARE AS FOLLOWS: PIPELINE SETTLEMENT, PIPELINE MISALIGNMENT, TEMPERATURE STRESSES, INTERNAL PRESSURE, AND CONSTRUCTION FORCES.