What do veteran divers think about Air vs Nitrox

[scubadobadoo]

IMHO, another example of an agency writing for the courts and not for divers' best interests. Does it make any sense to you that if you reduce the nitrogen fraction from say 79% to 64% that for the same pressure exposure the risk of DCS is the same? Horse pucky! And as to that second statement, without the reference for the study in which, "statistical estimates suggest that using enriched air within normal air limits only reduces the incidence rate a fraction of a percent," I frankly do not believe it. Just because nonsense finds its way into print does not mean that anyone should believe it without independent corroboration.

I never said or used the words, "risk is the same." I used and actually quoted PADI and those words were, "no meaningful advantage," and I am still waiting for anyone to prove them wrong. This is kind of like an Agnostic talking to a Christian, lol. I mostly believe (Agnostic) and you live it and teach it (Christian). How's that for a bad analogy?

Now, do I think it makes sense that reducing nitrogen helps? Sure, of course it makes sense but like Jim said, nothing can be proven here. Anyway, I don't teach it. I'm just quoting it. I'll leave the teaching to you.

 

[Charlie99]

If the fatigue thing is hard to pin down, think about how much fun it would be to try and prove or disprove the "oxygen is as narcotic as N2" issue.

Or to put it another way --- at the same depth, do you have less narcosis when on nitrox than when on air?

 

[Thalassamania]

I never said or used the words, "risk is the same." I used and actually quoted PADI and those words were, "no meaningful advantage,"

No, you offered up PADI's answer from the Basic Nitrox manual, "...simply reducing nitrogen is unlikely to produce a meaningful safety advantage." It is not unreasonable to say that if there is not a meaningful safety advantage that the "risk is the same." Those are, for the purposes of this discussion, equivalent statements.

Iand I am still waiting for anyone to prove them wrong

The onus for proof is usually on the proponent (you).

This is kind of like an Agnostic talking to a Christian, lol. I mostly believe (Agnostic) and you live it and teach it (Christian). How's that for a bad analogy?

The word agnostic comes from the Greek a (without) and gnosis (knowledge). While I am tempted, I will refrain from the sophist desire to tar you with the brush of being without knowledge. I for one question EVERYTHING and EVERYONE'S motives. That's what this is about. I question PADI's statement, I do not recognize anything that they publish as authoritative because I question their basic motives.

How's that for a bad analogy?

Smells like dirty sneakers.

Now, do I think it makes sense that reducing nitrogen helps? Sure, of course it makes sense but like Jim said, nothing can be proven here. Anyway, I don't teach it. I'm just quoting it. I'll leave the teaching to you.

Make up your mind (or are you of two minds?) Is it:

1) no meaningful advantage, or is it
2) sure, of course it makes sense.

Hard to have it both ways.

And you've still not supplied a refference for PAID's claim that "...statistical estimates suggest that using enriched air within normal air limits only reduces the incidence rate a fraction of a percent."

 

[scubadobadoo]

You are perfectly allowed to question PADI. I agree that they could be covering their ***. I also question the LDS's that lie to new divers and tell them that taking a nitrox course will make them feel better and make them safer and that those statements are facts and have been proven when they haven't. Even DAN can only RECOMMEND, they don't KNOW for sure so why the heck should I agree with you, lol?

I know for a fact that I am only guessing. You on the other hand, seem to know for sure that you aren't guessing about THEORY and that really makes you a dive "Christian." You believe because you believe, not because you can prove. I am simply unsure and I made that clear. I am truly Agnostic here. That's why I used the word agnostic. Theory isn't fact. I repeat, I don't really know the answer.

Now, if I am "without knowledge (Agnostic)," it is only because I was given this title because the person who made it up in the first place (the Christian) believed their knowledge was flawless, like you. Are you telling me that this theory is fact and that you can prove it?

When one puts the onus on another it usually means that they are full of ****.

I am of both minds. I thought I had made that clear. It makes sense, but I don't believe it (nitrox) offers a MEANINGFUL advantage over air, unless we are talking about a long week on a live-aboard and I mentioned that earlier too. The Big Bang theory makes sense too. Does that mean we all believe in it? The lottery is pretty hard to win. If I told you that you had about a 10% increased chance of wining the lottery would you call that a meaningful avantage? Sure, I'll take 10%, but it probably won't help, lol.

"Meaningful" and "risk is the same." LOL. Those are "for the purpose of this discussion" only the same BECAUSE YOU DECIDED THEY SHOULD BE TO HELP PROVE YOUR POINT.

 

[Doc Harry]

I think what PADI is saying is that, as mentioned in their course, the risk of DCS is already so low when following the guidelines that reducing it doesn't make a big difference.

I think this is very accurate and the whole point of PADI's comments on Nitrox as previously noted above by scubadobadoo.

But even though the risks are very low for the general population of rec divers, the risks are 100% if you are the unlucky person who gets a hit. That's why I use nitrox whenever it's available, to avoid being that unlucky statistic. I don't mind forking out the extra cash for the magic gas.

 

[scubadobadoo]

I think what PADI is saying is that, as mentioned in their course, the risk of DCS is already so low when following the guidelines that reducing it doesn't make a big difference.

Exactly. Like I said, a 10% increased chance of winning the lottery doesn't really help in a meaningful way when the chances are so low in the first place. Nonetheless, I'll take the 10% increased chance even if it is almost useless statistically, but I won't pay double for only 10%.

 

[TheRedHead]

I don't thnk money should be a factor when choosing the approrpiate gas for a dive when we're talking about $6 or so.

 

[scubadobadoo]

I don't thnk money should be a factor when choosing the approrpiate gas for a dive when we're talking about $6 or so.

Of course not, I think that is obvious and I agree eventhough I was kinda teasing above, but I rarely NEED to dive nitrox so it is therefore rarely the appropriate gas for me. Moreover, appropriate doesn't mean safer when comparing nitrox (rec. nitrox) to air. If nitrox is a more appropriate choice than air in your case then chances are you aren't choosing it for safety. Chances are you are choosing it to have longer BT's and that makes the dive on nitrox just as risky as the dive on air if you stay down longer. Now, if you are choosing it becasue you are a high risk diver, then you are choosing it because it may or probably or should be safer. Not becasue it WILL be safer. If I were a high risk diver I would use it and I do sometimes use it but I don't see a need to use it while at Dutch Springs for a day while doing two dives to 60 and then 50 feet for 35 minutes each. Please don't think I am bashing nitrox or nitrox divers. That's not the case. My comments should be read with a smile here. That is how they are intended.

Of course nitrox is safer than air when only thinking about the reduced nitrogen aspect, that I have never argued and believe, but I still say that advantage is very slim and so does DAN.

 

[Peter McGuinness]

I use it when I am on a trip, diving 3-5 dives a day for 5 or 6 days. I rarely use it to increase bottom times. I usually dive air tables (21% O2 setting on the computer) to add an extra margin of safety, which is particularly important when doing that much diving. Although there is no good empirical evidence, I am one of the people who believes that EANx also decreases fatigue. I don't use it at home in the Great Lakes, partly because a fair number of the wrecks are deep enough to push or exceed the MOD and partly because I do not keep a set of O2-clean tanks. Using EANx for Great Lakes diving would often mean dragging an extra tank or two along, so I have not gone to the bother and expense of keeping O2-clean tanks and dragging them around.

Actually, you *are* using it to increase bottom time. You have decided to increase your margin of safety, and if you were still diving air, that would imply reducing bottom time accordingly, either by using an altitude setting, or some other means.
Diving nitrox means you get the increased margin while still maintaining bottom times.
I agree strongly withe practice of diving nitrox on intensive dive vacations; I use it at the very least to draw down n2 ahead of the flight home.

Peter (happily splitting hairs)

 

[Peter McGuinness]

EAN was suggested to me due to the presence of significant scarring due to cervical surgery, titanium screws and plates and other scarring throughout my body. The reason for the suggestion was the lack of data about bubble formation in scarred areas. One school of thought is that reduced vascularity results in LESS formation, the other that reduced vascularity results in reduced off-gassing. I dive the richest mix I can get for my MOD, using air tables. I also feel less fatigue after diving....I am also middle-aged

cervical? uhh......you're a bloke!
Feel free to correct my anatomical assumptions but still....

Peter