MOBIL PIPE LINE COMPANY

Incident Narrative

CORROSION TECHNICIAN WAS MAKING HIS ROUTINE ROUNDS AT THE HWY 160 VALVE SITE WHEN HE NOTICED A FUGITIVE EMISSION ON VALVE #12217. HE INFORMED THE FIRST LINE SUPERVISOR, AND CONSEQUENTLY SENT A TECHNICIAN TO ADDRESS THE VALVE PACKING LEAK, RESOLVING THE FUGITIVE EMISSION. AT 10:37AM, WHILE ATTEMPTING TO REINSTALL THE INJECTOR PLUG, THE BALL CHECK LOCATED INSIDE THE INJECTOR FAILED. RGP BEGAN TO RELEASE THROUGH 1/8"" ORIFICE INSIDE THE INJECTOR TO ATMOSPHERE. AT 10:39AM, THE PIPELINE WAS SHUT-IN AND THE 8"" DOUBLE BLOCK BLEED VALVE WITH THE LEAKING INJECTOR WAS CLOSED, STOPPING THE LEAK. FOR SAFETY PURPOSES, THE TECHNICIAN BLED DOWN THE VALVE CAVITY TO SAFELY REPAIR THE INJECTOR. VERIFICATION OF REPORTABLE CRITERIA BEING MET WAS AT 3:31PM (15:31) CENTRAL STANDARD TIME. THE INCIDENT INVESTIGATION CONCLUDED THAT THE PACKING INJECTOR FAILED TO PERFORM AS DESIGNED. TO PREVENT REOCCURRENCE, OPERATIONS INSTALLED A BALL VALVE BETWEEN THE MAINLINE VALVE BONNET AND A NEW PACKING INJECTOR. THIS REPAIR METHODOLOGY WAS REVIEWED WITH THE EXXONMOBIL VALVE SUBJECT MATTER EXPERT TO ENSURE ADEQUACY FOR THIS PARTICULAR VALVE DESIGN AND FAILURE MECHANISM. REGARDING PART E, QUESTION 5, THIS ACCIDENT DID NOT REQUIRE AN UPSTREAM OR DOWNSTREAM ISOLATION, SINCE THE VALVE IS A DOUBLE BLOCK AND BLEED EXPANDING WEDGE GATE VALVE.