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6Gill · 3rd January 2007, 14:27

I believe the USN has abandoned the 60 for 30 O2 tolerance test. We used to do this in the seventies when I was in; and I did have 2 guys (out of about 150 that I tended) tox on the tests while I was a chamber tender. Since I left, I'm told the Navy reached the conclusion that the test really wasn't valid as a person could pass it one day and fail at a future date. PO2 above 2.0 would be an option in combat or with FFM but IMHO probably isn't worth the elevated risk in sport diving.

Quote: (Originally Posted by pimderhoodes)

Reading the stories about ppo2 from Joe,

In water-pure 02 deco at 40 FSW was observed by me personally for literally *thousands* of hours., right out of the US Navy dive manual and using the tables custom produced for us by Dr. Bill Hamilton..... and we never saw an 02 tox symptom ever. We did *much* longer 40 foot chamber decompressions (hours) after the in-water portion of the deco was done and never saw an issue there either. Every 6 months each diver did a 60 FSW for 30 minute chamber run on pure 02 for the "02 tolerance test" and in literally hundreds of chamber runs we *never* had a hit. Don't take me wrong: 02 tox *is* an issue, just that it's a "fuzzy" limit and not a "hard" one. Go see how the SEALs use LAR-V's for emergency combat escape dives to 75 feet plus (diving in an emergency to below hand-grenade sinking depth) and then talk to me.

makes me ask the question to all of you, how much PPO2 do you use during the dive ?
Are you putting it to the max of 2.0 ? or just doing deco at 2.0.
Or are we all doing the "normal" 1.5 / 1.6

thanks pim

3rd January 2007, 14:27	#7 (permalink)
6Gill Custom Title Allowed! Current Rebreather/s: Megalodon Classic Kiss Other Rebreather/s: Join Date: Apr 2006 Location: Washington state Posts: 112	Re: max PPO2 I believe the USN has abandoned the 60 for 30 O2 tolerance test. We used to do this in the seventies when I was in; and I did have 2 guys (out of about 150 that I tended) tox on the tests while I was a chamber tender. Since I left, I'm told the Navy reached the conclusion that the test really wasn't valid as a person could pass it one day and fail at a future date. PO2 above 2.0 would be an option in combat or with FFM but IMHO probably isn't worth the elevated risk in sport diving. Quote: (Originally Posted by pimderhoodes) Reading the stories about ppo2 from Joe, In water-pure 02 deco at 40 FSW was observed by me personally for literally thousands of hours., right out of the US Navy dive manual and using the tables custom produced for us by Dr. Bill Hamilton..... and we never saw an 02 tox symptom ever. We did much longer 40 foot chamber decompressions (hours) after the in-water portion of the deco was done and never saw an issue there either. Every 6 months each diver did a 60 FSW for 30 minute chamber run on pure 02 for the "02 tolerance test" and in literally hundreds of chamber runs we never had a hit. Don't take me wrong: 02 tox is an issue, just that it's a "fuzzy" limit and not a "hard" one. Go see how the SEALs use LAR-V's for emergency combat escape dives to 75 feet plus (diving in an emergency to below hand-grenade sinking depth) and then talk to me. makes me ask the question to all of you, how much PPO2 do you use during the dive ? Are you putting it to the max of 2.0 ? or just doing deco at 2.0. Or are we all doing the "normal" 1.5 / 1.6 thanks pim __________________ "It's a shame ignorance isn't painful!"
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