Quote: (Originally Posted by
jradomski)
the one thing to note on the classic is that the duration is stated at 40m.. most of the other rigs tested state the max duration based on ~20m testing..
Yes Joe. I don't know why the EU use the 20M depth, the 18M depth for the Prism unmanned testing was specified by USN. The unit was tested at multiple depths, both manned and unmanned and the results have not been released yet. Maybe Alex can clarify why 20M was chosen by the EU. Maybe it's an average depth of a typical recreational profile? I don't know. Would testing a scrubber with a continuous flow at an average depth be a good way to evaluate it and make planning your dives around this time simpler? Maybe, but again, I don't know if averages are an accurate way to plan scrubber life on a multi level dive.
I think useful testing could be of 3 kinds:
1) Unmanned coldwater testing of common profiles for CCR like say, a 70M dive with a 30 minute bottom time at a moderately high workload and of course the deco stops that come with them.
2) A sort of sprint test to see just how high the CO2 flow would have to be to bypass the scrubber at the beginning, middle and end of a given scrubber's life, like Stefan suggested.
Or 3) Just test every 10M depth down to 150M in cold water at a moderately high workrate unitl breakthrough and maybe these data could be put into dive planning software like any other element of dive planning-deco obligations, O2 exposure, gas consumption, etc.
It would be nice to have limits we could use in real world diving, instead of worst case scenerios. Doesn't seem like so much to ask for...