DOMINION HOPE

Incident Narrative

AT 06:09 ON 10/08/2013, AN OVERPRESSURE EVENT OCCURRED ON DOMINION HOPE GAS' MAIN PIPELINE (HM-3095). THE ROOT CAUSE WAS THE FAILURE OF HOPE GAS REGULATORS DUE TO ICING CONDITIONS. THESE REGULATORS ARE LOCATED IN STATION HX-363 AND REDUCE PRESSURE FROM OVER 500 PSIG TO 70 PSIG. AT 06:47, A SERVICE PIPELINE THAT IS CONNECTED TO M-3095 RUPTURED, CAUSING A BLOWING LEAK. THE SYSTEM WAS ISOLATED AND COMPLETELY SHUT DOWN AT 8:10. NO INJURIES OR PROPERTY DAMAGE OCCURRED. A CONSULTANT (JANA LABORATORIES, INC.) WAS EMPLOYED TO ANALYZE THE INCIDENT AND RECOMMEND CHANGES. AS ADVISED BY JANA LABS' PRELIMINARY REPORT, DOMINION HOPE GAS IS IN THE PROCESS OF INSPECTING AND/OR REPLACING VARIOUS COMPONENTS OF THE AFFECTED PIPELINE SYSTEM. TESTING OF THE PIPELINES AND THE REGULATING/METERING STATIONS WILL BE PERFORMED IN ACCORDANCE WITH 46 CFR PART 192. THE SYSTEM WILL BE PLACED INTO SERVICE ONLY WHEN ALL COMPONENTS ARE DEEMED SAFE AND OPERATIONAL. AS REQUESTED BY DOMINION, JANA LABORATORIES IS COMPILING AN ADDITIONAL REPORT TO RECOMMEND LONG-RANGE PLANS AND CONCERNS. COMPLETION INFORMATION: A CONSULTANT (JANA LABORATORIES) COMPLETED AN EVALUATION OF THE AFFECTED PIPELINE SYSTEM: 5.0 RECOMMENDATIONS BASED ON THE ANALYSIS TO DATE AND THE TESTING OF THE SAMPLES RECEIVED, THE FOLLOWING RECOMMENDATIONS ARE MADE:  THE OVERPRESSURIZATION RESULTED IN THE EXPOSURE OF THREE REGULATOR STATIONS, THE HDPE MAINLINE, AND THE MDPE BRANCH TO INCREASING PRESSURE UP TO >500 PSIG (MAXIMUM 528 PSIA, OR 513 PSIG), RAMPING UP OVER A PERIOD OF APPROXIMATELY ONE HOUR. THE ROOT CAUSE WAS REPORTEDLY THE FAILURE OF REGULATOR STATION HX-363 TO REGULATE PRESSURE FROM THE TRANSMISSION LINE DUE TO FROZEN WATER IN THE REGULATOR RUN.  THE INTEGRITY OF THE PIPES AND FITTINGS HAS BEEN ASSESSED AS FOLLOWS: O 6"" HDPE PIPE AND ASSOCIATED HEAT FUSION, ELECTROFUSION, AND TRANSITION FITTINGS: NO EXPECTED IMPACT OF OVERPRESSURIZATION ON LONG-TERM PERFORMANCE O 6"" HDPE BALL VALVES: NO EXPECTED IMPACT OF OVERPRESSURIZATION ON LONG-TERM PERFORMANCE O 4"" MDPE PIPE AND ASSOCIATED HEAT FUSION, ELECTROFUSION, AND TRANSITION FITTINGS AFFECTED (PIPE BURST); NON-BURST REGIONS EXPOSED TO PRESSURE CLOSE TO TENSILE LIMIT O 4"" MDPE BALL VALVE: POSSIBLY AFFECTED; EXPOSED TO PRESSURE CLOSE TO TENSILE LIMIT  THE INTEGRITY OF THE REGULATOR STATIONS HAS BEEN ASSESSED AS FOLLOWS: O HX-363: NOT EXPECTED TO BE AFFECTED; ROOT CAUSE ANALYSIS OF ENTRAINED WATER FREEZING ADVISED BEFORE REPRESSURIZATION O TYGART VALLEY REGIONAL JAIL: POSSIBLY AFFECTED; METER, VALVES, AND REGULATORS EXPOSED TO PRESSURE > MAOP O IS-267: POSSIBLY AFFECTED; METER, VALVES AND REGULATORS EXPOSED TO PRESSURE > MAOP  ALL POTENTIALLY AFFECTED COMPONENTS SHOULD BE CLOSELY EXAMINED FOR DAMAGE (IN SIMILAR FASHION TO HX-363 AFTER THE INCIDENT) AND REPLACED IF DAMAGE IS FOUND. IT HAS BEEN INDICATED THAT THE JAIL REGULATOR STATION AND THE ENTIRE MDPE LINE ARE SCHEDULED TO BE REPLACED.. 1 . REGULATORS WERE COMPLETED DISASSEMBLED AND INSPECTED AT ALL THREE STATIONS BY A CONSULTANT (MASTER CONTROLS). REGULATORS WERE FOUND TO BE UNAFFECTED BY THE OVERPRESSURE SITUATION. 2 TWIN 3X4 MERCER RELIEF VALVES WERE INSTALLED AS ADDITIONAL OVER-PRESSURE PROTECTION AT THE HIGH PRESSURE CUT REGULATION STATION. 3. BRUEST PILOT HEATERS WERE INSTALLED ON THE HIGH PRESSURE CUT REGULATION STATION. 4. NEW STEEL ENAMEL BUILDING INSTALLED OVER THE HIGH PRESSURE CUT REGULATION STATION TO PROTECT HEATERS FROM THE WIND. 5. MDPE PIPE WAS REMOVED AND REPLACE WITH HDPE. 6. ENTIRE SYSTEM WAS RETESTED WITH AIR TO 155 LBS. 7. COMPLETE STATION INSPECTIONS WERE PERFORMED WHEN GAS WAS REINTRODUCED. GAS WAS REINTRODUCED ON 11/25/13.