Quote: (Originally Posted by
PaulTG2)
If you run a PO2 of 1.3 you would have 8 x 1.3 or 10.4 lts or O2. To get to a PO2 of .2 you would have to use 8.8 liters of O2 -- or almost 9 minutes at a 1.0 lpm O2 comsumption rate.
That amount of time you have is dependent on the loop volume and initial PO2 set-point. It doesn't vary with depth.
To me that's a pretty good buffer, even at higher consumption rates.
Anyone see a hole in my logic?
-p
Thanks for the reply. I would not call it a hole in your logic, but I would add a caveat just to close the loop (so to speak
) ...
The scenario under consideration assumes a diver ascends from 50m starting at a PO2 of 1.3 without additional gas added to the loop.
If the diver ascends at a rate of 20m/min and consumes 1 lpm of O2 along the way, the diver will surface with a PO2 of about 0.11, with some variation depending on loop size and other variables.
In this case, within just a couple of minutes (not 8 or 9) a very comfortable PO2 has become life threatening. Ascent should always be considered a time for extreme diligence.