50% O2 and and O2 for deco...........WHY? also labelling tanks........WHY?

[wedivebc]

Pls paraphrase point 13 for me

As to the CNS% thing, its kind of a fake concept. You can tox before hitting 100% and passing 100% doesn't mean you will tox. The "risk" of crossing 100% isn't even quantified.

So in your estimation the CNS clock thing is just a rough approximation not to be taken too seriously but the 1.6 oxygen window is a minuscule target that requires precise accuracy?
Just my interpretation of Trey's rant

 

[PfcAJ]

AJ does not equal Trey.

I (AJ, not speaking for anyone else) think the CNS% thing is capital baloney. I'd be long gone if that thing were even close to accurate.

I also don't find it that hard to hold a stop within a foot or so. I think a tech diver SHOULD be able to hold a stop within a foot or so with ease.

 

[100days-a-year]

There won't be any way to quantify the effect of long term elevated p02 on recreational divers until there have been enough of them doing it long enough to have developed any conditions that take a long time to induce.That means subjective opinions on it's relative safety are moot at best and foolish at worst.


Discussed here is one considerationhttp://www.scubaboard.com/forums/ask-dr-decompression/96586-aseptic-bone-necrosis.html

 

[kwinter]

I also don't find it that hard to hold a stop within a foot or so. I think a tech diver SHOULD be able to hold a stop within a foot or so with ease.

Have you got a jon line AJ? Come on up here and let's do some rock n roll northeast wreck diving. Last time on the Doria the swells were bouncing me at least 10-12 feet, even with the jon line. A tech diver ain't no match for God or King Neptune.


Please pardon any typos. Sent from my iPhone using Tapatalk

 

[PfcAJ]

Sounds miserable. I dive for fun.

 

[swimguard]

AJ does not equal Trey.

I (AJ, not speaking for anyone else) think the CNS% thing is capital baloney. I'd be long gone if that thing were even close to accurate.

I also don't find it that hard to hold a stop within a foot or so. I think a tech diver SHOULD be able to hold a stop within a foot or so with ease.

The CNS clock is place NOT because you will tox right at that moment you hit 100% but to give you a buffer of high o2 exposure to allow a doc to press you if you get bent.

There does come a point where your o2 exposure can become too high where someone can't put you into a chamber. I am not a doc so I don't know that magic number but the more you go over 100% the less wiggle room a doc has in the chamber to treat you, especially if you need multiple rides....

 

[PfcAJ]

Interesting. A buddy of mine got bent on a REALLY long dive with a ridiculous CNS% and I was with him when he went into the chamber.

Citation for your claim, please?

 

[karstdvr]

I use 80% instead of 100% because I do think it is safer by a small margin.

Studies have shown the off gas gradients between O2 and 80% are not that much different. On a sidenote,how many people test the oxygen? Very rarely does anybody get 100% from suppliers,and I have seen numbers as low as 92% Which,yikes,what is the other 8%? Which inspite of the variance of oxygen %s from suppliers,this minute difference doesn't seem to cause wholesale problems.

 

[Hickdive]

It is far more likely that the analyser cell used to analyse the gas is current limited than the oxygen is impure.

If the "oxygen" content was less than 100% this would manifest itself in incorrect nitrox blending results at lower concentrations.

 

[PfcAJ]

Yeah I've never seen low o2 like that.