OXTOX limits - MOD, PPO2 or CNS Clock?

[berk]

Andy, what are in the standards and instruction regarding going deeper than MOD? (rescue etc.) Perhaps nothing due to liability issues.

 

[PfcAJ]

Ok wiseguy. Should divers have such a fear of going beyond a 1.6 PO2 that they would opt NOT to rescue a buddy who has gone deeper than their "MOD"?? Which btw, I've seen people post this scenario: "What else could I do? I didn't want to go deeper than my MOD even though my buddy appeared to be in trouble"

How many divers have toxed by NOT exceeding the 100%?

Shouldn't people at least have the benefit of WHY 1.6 is the agreed upon MOD, rather than the general methodology of teaching students to avoid at all costs "violating the MOD or you will die" approach that is the norm.

Easy there.

I'm just sayin that the clock thing isn't valid. If you need to go beyond 1.6 to save your buddy's life, then go for it. I would do it RIGHT now, without hesitation.

I think the lady that passed at "The Crack" (cave) a few years ago was quite inside the 100% limit. Could be wrong, though. There was a guy at Ginnie (cave) a number of years back that died from "unexplained reasons" (one of those where the ME report says 'drowning') that was on 36% or somethin like that. There have been some more that are suspected o2 issues, as well. Its hard to say for sure since there isn't any evidence unless someone witnesses it.

I think the value of the clock is over rated. If it was a real thing, then bad stuff would happen when you hit 100%, and it doesn't.

 

[The Chairman]

I was trying to edit the thread at the same time another mod was. I think I killed it as I can't find it anywhere. I apologize for the inconvenience.

 

[The Chairman]

I have exceeded 1.6 to enact a rescue. I would do it again. As an instructor, I would never suggest exceeding any limit to a student. I do avoid "or you're gonna die" scenarios.

 

[HowardE]

I'm just sayin that the clock thing isn't valid. If you need to go beyond 1.6 to save your buddy's life, then go for it. I would do it RIGHT now, without hesitation.

It's not invalid either. It's just a general guideline, not a rule. It's advised that you don't exceed the clock. My dive buddy has done 200% of his clock several times. The point is - that OxTox isn't an instantaneous thing, as the Nitrox classes would lead people to believe. It's a function of TIME and EXPOSURE. That's my point.

I think the lady that passed at "The Crack" (cave) a few years ago was quite inside the 100% limit. Could be wrong, though. There was a guy at Ginnie (cave) a number of years back that died from "unexplained reasons" (one of those where the ME report says 'drowning') that was on 36% or somethin like that. There have been some more that are suspected o2 issues, as well. Its hard to say for sure since there isn't any evidence unless someone witnesses it.

I think the value of the clock is over rated. If it was a real thing, then bad stuff would happen when you hit 100%, and it doesn't.

The value of the clock needs to be - that you shouldn't exceed 100% in a day. That you shouldn't plan a dive that exceeds 100%. Some people may have a higher tolerance to the clock times.

My dive buddy was a commercial diver for many years. When he started commercial diving - they did a "test". Basically - get into the chamber, and dial up the PO2 to 2.0 - and wait 30 minutes. If the guy toxed... they couldn't be a commercial diver.

There is NO rule to who toxes out and when. But I think people are too quick to conclude Ox Tox, when its a mystery, mostly because they've been taught all along "Don't Violate your MOD or you will die" - That is what pisses me off.

 

[PfcAJ]

I think we're in agreement, for those most part, then.

I've exceeded 100% on a single dive many many times, and 200% a number of times. I see why agencies can't recommend that, but I also think a whole lot more research into oxygen toxicity is needed so we can make realistic, accurate, guidelines.

A max ppo2 of 1.2-1.4 working and 1.6 for deco seems to be working out pretty well. Its the clock thing that I think is questionable.

 

[HowardE]

I think we're in agreement, for those most part, then.

I've exceeded 100% on a single dive many many times, and 200% a number of times. I see why agencies can't recommend that, but I also think a whole lot more research into oxygen toxicity is needed so we can make realistic, accurate, guidelines.

Exactly

 

[berk]

I think the value of the clock is over rated. If it was a real thing, then bad stuff would happen when you hit 100%, and it doesn't.

True, accuracy is very over-rated, but the value is still there.

The flip side is consequence. It's meant to keep one very clear of problems. You can survive getting bent, often with zero consequence. The odds of surviving a CNS toxicity seizure are not favorable on recreational SCUBA gear and the situation is always dire.

-matt

 

[berk]

I also think a whole lot more research into oxygen toxicity is needed so we can make realistic, accurate, guidelines.

And whole lot more lawyers for the agencies too to look at the research

 

[jtivat]

I see it both way those that think they will die if they cross that magic 1.6. Then there are all these new tech divers that want to push the limits and are using 1.4 and 1.5 for there bottom mix to save a few minutes of deco. For me on a big dive I like to keep it under 1.3 will I die if it is higher most likely not but why push it to save a little deco???