(112d) Ruptured Rupture Disc

The FRI distillation unit in Stillwater, OK, contains 11 relief valves and 2 rupture discs.  One of those rupture discs protects the steam system that drives the FRI reboilers.  On 4 June 2012, FRI purposely blew that rupture disc.  Video cameras were placed at four outside locations and at one location inside the control room.  Birds seemed to know when the disc was about to rupture.  The event was loud.  As a result of this study, FRI gained additional confidence in the discs that had been used successfully for many years. 

            Enclosed vessels, the ones that experience internal pressures in excess of ambient pressures, must be protected from over-pressurizations.  Those vessels can be protected with relief valves or with rupture discs.  When those valves/discs blow open, the resultant rapid depressurizations are shocking, frightening and loud.  When those valves/discs fail to open, or when they were not engineered into the processing system in the first place, the resultant rapid vessel depressurizations - - - are far worse - - - and people sometimes get hurt.