| I choose gases to give 1.0 bar ppO2 during the dive for trimix or a max of 1.2bar on EAN and then hike them up on deco. I use O2 at 6m on most deco dives and to be honest I never bother calculating the %CNS thingie, even for long dives. I'm not even convinced the whole idea that the percentage concept even works, it has no experimental basis and was just thought up by IANTD when they were writing the courses. In my view, there are more factors at work. For example, you can tolerate 1.6 ppO2 on a nitrogen based gas a lot longer than you can tolerate 1.6bar on pure oxygen. I just don't think it is as simple as trading off the various limits as in the %CNS idea.
__________________ "I hate to advocate drugs, alcohol, violence or insanity to anyone, but they've always worked for me" Hunter S Thompson http://www.snp.org |