Do you think Nitrox is a deep diving gas?

[Thalassamania]

Actually, this is the recurring theme for the "old timer" , "...has more to do with a paucity of knowledge and experience". It seems to be the precurser to "I know better than you" and, "I didn't mean to insult your lack of knowledge and experience"...

You left out a few: I've forgotten more than you've learned to date; when you reach my level you'll understand ... until then you'll just have to take my word for it, "Genius has no youth, but starts with the ripeness of age and old experience." (Mark Twain); "Experience is not what happens to a man. It is what a man does with what happens to him." (Aldous Huxley); "Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so." (Douglas Adams); etc.

 

[BHB ScubaTroll]

You left out a few: I've forgotten more than you've learned to date; when you reach my level you'll understand ... until then you'll just have to take my word for it, "Genius has no youth, but starts with the ripeness of age and old experience." (Mark Twain); "Experience is not what happens to a man. It is what a man does with what happens to him." (Aldous Huxley); "Human beings, who are almost unique in having the ability to learn from the experience of others, are also remarkable for their apparent disinclination to do so." (Douglas Adams); etc.

Nope... I left them out... based on courtesy.... :cool2:

 

[Thalassamania]

Nope... I left them out... based on courtesy.... :cool2:

And best of all, "Old age and treachery will overcome youth and enthusiasm."

 

[Reg Braithwaite]

And best of all, "Old age and treachery will overcome youth and enthusiasm."

Hey! That's the line I use when cycling or playing Ultimate! My version is "Experience and treachery will overcome youth and talent," but close enough

 

[HowardE]

Howard, we are in violent agreement about estimating the risk of a seizure using the generally accepted tables for exposure. My understanding is that deco chambers have a slightly different risk scenario because you are not going to spit your mouthpiece out and drown if you have a seizure. Likewise, if you are in a chamber and suffering from DCS, the treatment plan weighs the risk and consequences of toxicity against the risk and consequences of prolonging your exposure to DCS. Is that true? If so would that play a part in a deco chamber being willing to dial the PPO2 up to 2.0?

Actually. What do you think the Exposure table leads to (tells us)? The simple explanation that is most often left out of basic nitrox courses is that - If you exceed the limits set forth on the tables, you risk the increased danger of oxygen toxicity (seizure) hits; so it's not just black and white like the standard dogma says, "don't exceed 1.6 PPO2 - period - EVER - or you will die"

My point is. The current training method uses scare tactics to scare people from exceeding 1.6 PPO2 because of eminent (immediate) danger. In reality, there is time at that level of exposure, or even greater levels of exposure to make an educated decision as to what actions need to be accomplished, and weigh the risks and lack there of to exposure yourself to high ATA's of Oxygen Partial Pressure.

Let's say you're out of back gas for some reason, and you're at 100 feet. All you have is a bottle of 50% for deco. Do you breathe it and breathe O2 at 2ATA's, or do you blow and go up to 70' rapidly; right away so you can stay below the magic 1.6 ATA's?

Certainly there is no risk of drowning in a chamber, but what is the % of incidence in chambers where people actually do tox from oxygen? (I don't know).

When I took my rebreather training, one of the students was a hyperbaric doc, and he told me that it's extremely rare for ox tox in the chamber, and more often than not it's a hypoglycemic event (convulsion), rather than a hyperoxic event. I don't have numbers on this, so maybe someone else may know more.

 

[DeepSeaExplorer]

If Nitrox has reduced incidents of DCS, it's probably only because new divers can't hit the NDL of Nitrox on shallow dives and have to ascend due to gas volume limitations before they can accumulate enough N2 to get bent. So if every new diver were required to use Nitrox and small tanks; theoretically, they could not get bent, excepting AGE.

On recreatinal dives, Nitrox gives you more bottom time at almost every depth, even though it may only be a couple of minutes. Where it really excels is in the 60 to 90 foot range. I've mixed Nitrox for 150 dives, so you can use it for back gas at deeper depths. However, because of the PPO2 limitations, I generally think of it as a deco or shallow water gas, if only because there are other more appropriate gases for deeper dives.

 

[OneBoatNut]

Depends on the definition of “Deep” to me that is over 250 feet.
Depends on your independent physiology and ability to metabolize inert gases.
Depends on your O2 toxicity, which is the real unknown

Really now we all know depth increases inert gas metabolic rate and oxygen toxicity.
So why ask such a question?
It would be a great gas after a ˜160FSW dive for the trip back and deco stages; nice gas switch for the camp out time and stops.

 

[OneBoatNut]

Howard E is spot on.

 

[Kern]

Depends on the definition of “Deep” to me that is over 250 feet.
Depends on your independent physiology and ability to metabolize inert gases.
Depends on your O2 toxicity, which is the real unknown

Really now we all know depth increases inert gas metabolic rate and oxygen toxicity.
So why ask such a question?
It would be a great gas after a ˜160FSW dive for the trip back and deco stages; nice gas switch for the camp out time and stops.

Inert gasses aren't metabolised. Some non inert gasses are physiologically inert & so by definition aren't metabolised. These gasses are on & off gassed without entering a metabolic pathway.

 

[BHB ScubaTroll]

lets keep the discussion in the 99fsw-140fsw range. Divers choice of O2 with no He

The OP did attempt to define the parameters the day after he posted the original thread

It appears this thread has overrun its course