Assuming depth of 40 meters, diluent 21% O2(air), do I not have roughly 20 breaths on the loop before venting and manually refilling my inhalation bag? Assume my electronics have failed and I have no means to measure loop po2.
Again this is assuming I'm in bailout mode with no means to introduce pure O2 to the loop.
If I were on the surface, the ratio would obviously be 4 breaths to every vent, so @ 5atm, I should have 20 breaths right?