what the different between using Nitrox and Normal Air to dive???

[boulderjohn]

My original question at the start of this is was there an oxygen tolerance test being done before starting a nitrox class. From that point on I have just quoted the Navy on nitrox use. In my opinion it is fine for the purpose it was intended and that was for use at shallow water decompression stops. The deeper you go from there the more risk you open yourself up to so that test seems like an easy precaution for anyone using it below 50'.

Please show me where the Navy manual says this. I don't want your decision making about the data--I want to see where the Navy manual says what you say it says. When I read the same thing you do in that manual, I draw the exact opposite conclusion. It seems to me it is recommending its use, not discouraging it.

 

[Rich Keller]

Blindly following anything is the worst thing you can do, no one really knows how Oxygen toxicity occurs no one really knows how decompression works, and that includes the US navy, so you educate yourself, be a thinking diver and make your decisons.

One thing to consider, how many dives a year do you think US navy divers make a year in total, how many dives do divers from the main rec/tech agencies make a year? Hell I'd be willing to bet the divers on this board make more dives a year than the US navy do.

What you said was the "divers from main rec/tech agencies" not the WHOLE rec/tech community! The entire rec/tech community is not doing research just the ones working at the agencies! Again putting a spin on what I said!

 

[boulderjohn]

It is well established that ppO2 1.4 or lower does not cause statistically significant number of CNS toxicity cases. Recreational Nitrox is used below that threshold, or at least Nitrox classes teach you that. EANx 32 is about as safe as air from tox point of view below 100 feet and has significant benefits from a lower percentage of Nitrogen in it.

And that is almost exactly what the Navy manual says, as I quoted earlier. It baffles me that this document is being used to support an argument to the contrary!

 

[Elvistheking]

What you said was the "divers from main rec/tech agencies" not the WHOLE rec/tech community! The entire rec/tech community is not doing research just the ones working at the agencies! Again putting a spin on what I said!

Oh I'm sorry replace Whole rec/tech community with "divers from the main rec/tech agencies", so who aren't the main ones and we can exclude them, that'll only leave 95% of divers instead of 99%, erm OK I think lets exclude that recreation CCR one, they must be pretty small, erm that German DIR one, err any more?

The recommendations are being shown to work by the fact that loads are not Ox Toxing at 1.4 bar, I prefer my absolutely mahosive data set to you sorry (and it would appear so does the US navy diving manual).

 

[ianr33]

It is well established that ppO2 1.4 or lower does not cause statistically significant number of CNS toxicity cases.

Kinda depends how long you breathe it for. Would you breathe a pO2 of 1.4 for a week?

 

[chokolad]

Kinda depends how long you breathe it for. Would you breathe a pO2 of 1.4 for a week?

Here you will have problems with pulmonary toxicity, not CNS. And again, at recreational diving depths and bottom times it is pretty hard to get close to pulmonary tox limit. It becomes an issue when decoing on 50% or 100% o2.

 

[Ana]

My original question at the start of this is was there an oxygen tolerance test being done before starting a nitrox class. From that point on I have just quoted the Navy on nitrox use. In my opinion it is fine for the purpose it was intended and that was for use at shallow water decompression stops. The deeper you go from there the more risk you open yourself up to so that test seems like an easy precaution for anyone using it below 50'.

Thanks, I appreciate the clarification.

now.. on your quote below I see more uses for NITROX besides shallow decompression.

"NITROX breathing gas mixtures are normally used for shallow dives. The most benefit is gained when NITROX is used shallower than 50 fsw, but it can be advantageous when used to a depth of 140 fsw.

BEST used shallower than 50fsw
ADVANTAGEOUS down to 140fsw

right? isn't advantageous a good thing? there is no warning on the statement, granted there are rules to follow,of course. Everything in diving has something that could bite if not done correctly.
Why wouldn't the rec community use something that is considered advantageous.
I mean looking back, maybe at the beginning it may have been prudent to test people for their oxygen tolerance, but seems to me it has been well proven that people in general tolerate NITROX fairly well... have you seen the completely out of shape fat asses that get on dive charters sometimes, if the risk was a factor tons of people would have crocked by now... just my opinion.

Funny thing is that I work in the bldg directly behind the NEDU bldg, when I left to lunch a bit ago, I was actually tempted to walk in there and ask them what is their position on NITROX, then I came to my senses...not only is Friday afternoon during spring break so very few people would be there, also I remembered the cartoon with the guy telling his wife he can't go to bed just yet because someone in the internet is wrong.

 

[ianr33]

Here you will have problems with pulmonary toxicity, not CNS.

You totally certain about that i.e I can breathe a pO2 of 1.4 for as long as I like and not worry about CNS toxicity?

Damn.Obviously wasted my money on that silly Trimix course.

(I agree with you about the pulmonary issue.Lets just consider CNS)

 

[Elvistheking]

Kinda depends how long you breathe it for. Would you breathe a pO2 of 1.4 for a week?

Either your carrying around some seriously massive cylinders (you know your not supposed to use J's to dive with?) or your SAC must be through the floor (or both).

 

[ScubaSteve]

They are also talking to more qualified people then just sport divers!

Well obviously you are on their payroll right?