Quote: (Originally Posted by
Humuhumu)
Personaly I can live with a PpO2 of 2.1, it will not be a problem if the situation is not lasting: this means if this happens you will have to go on the bail out, that's it ! That's why I have a 80 cft AIR, with me.
The problem is that the pO2 spike IS long lasting. Realistically, you won't hit 2.1 as there is still a proportion of 'used' gas in the loop [hoses and scrubber].
Let's say you end up with a pO2 of 1.9 after a flush-at 60m an fO2 of 27%. In a loop of 10.5L volume, that is 2.85L of O2-
surface litres. If you are at 60m it is equivalent to 19.95L because of the pressure at that depth. If you were injecting 28% into the loop at a flow rate of 10.4 L/min you will be injecting 2.9 L/min of O2 into the loop. With your low vO2 the pO2 spike will last a long time. The only thing you could do to reduce it, other than ascend, is to turn off your supply gas and wait for the pO2 to drop, and the deeper you are the longer it will take.
Best not to forget to turn the tank back on!