Quote: (Originally Posted by
Dave Sutton)

Better to isolate gas in front of any subsystem rather than behind. This produces two advantages with one part. Typical alpine mindset.
Dave
My mindset is to 'rely' on the Rebreather breaking down

(allthough it hardly ever goes wrong) and have a BOV on diluent with FO2>=21% + a stage so for now I'll leave it in the current position. I agree with what you say but would hate to loose the stuck_kiss_valve_when_ball_valve_is_closed safety net allready. The design principle itself I'll try to engrain in my mind.