Wreck Penetration

[AquaTec]

So, what's the deal? Is it know that O2 is not as narcotic as nitrogen or is just suspected? I thought I read in my Dir-f book that O2 had an even higher nacrotic potential

I agree whats the deal, the only place i have ever heard this is from people who have read it in a DIR manual, I would love to see some evedence of the "Narcotic" effects of oxygen.

I though that EAD (in terms of NITROX) was just for NDL stuff not for how now narced you are going to be?

EAD is relative to NDL in the fact that the EAD will be shallower than your actual depth therfore allowing you a longer NDL dive.

If I'm diving at 100' with EANx32 is my head really going to clearer than air? I dive with nitrox and air and I really can't tell, but, am I supposed to be not as narced?

Narced is a relative term, you may not feel narced until you are at 130 feet on air and therfor you EAD would need to be 130 to "feel" the same but your actual depth would be deeper if on nitrox. the effects of high Pn2 would be less at 100 ft using 32% than it would be on 21%

This is why I like the tech forum, I know you guys all know your stuff, but, I read in Ontario Diver's last post that NITROX is good for the 100-180' range. Could some explain this? After about 100-130' don't you need air (or TRIMIX with 21% or less of O2) to prevent from taking an O2 tox hit? [/B]

[/QUOTE]
first off deeper than 100 feet trimix is better than other mixes
but keeping with using just nitrox and using a maximum Po2 of 1.6 which may not be your best choice. your "best" mixes are as follows

100 feet = 39.8%
130 feet = 32.5%
180 feet = 24.9%
219 feet = 21.0%

with a Po2 higher than 1.6 at any depth leaves you highly vunrable to a tox hit, even if you are at 30 feet deep, it is not the depth, it is the Po2 that leads to a tox hit


hope that explains it a bit. it is 2:00am and i have been drinking
=-)

 

[AquaTec]

JT2 once bubbled...
6. Narcotic factors of gases:
Narcotic factors of gases:

(Chemical sign, name, factors (divide by / multiply by) )

He, helium, 4.26 / 0.23
Ne, neon, 3.58 / 0.28
H2, hydrogen, 1.83 / 0.55
N2, nitrogen, 1 / 1
Ar, argon, 0.43 / 2.33
Kr, krypton, 0.14 / 7.14
Xe, xenon, 0.039 / 25.64

(Source: "The Physiology and Medicine of Diving" by Peter Bennett and David Elliott, 4th edition, 1993, W.B.Saunders Company Ltd, London.)

The table above is based on narcotic effect of air (=1). So, for example, xenon (as diluent gas in same percentage as nitrogen in air) in breathing mix is 25.64 times as narcotic as nitrogen. Or helium is 4.26 times less narcotic than nitrogen, etc.
It is also good to know, than oxygen is narcotic in high partial pressures. Some sources claim it to be as narcotic than nitrogen (Bill Hamilton, http://www.tekniskdykking.org/tekniskdykking/artikler/aqua/RWHNitrox.htm.

I thought this was a good comparison of narcotic factors...

I would like to see this link but it doesn't open

also if oxygen is narcotic why is it not on your list...good list by the way

 

[dothanfrogman]

So from what I gather IANTD or the like will be my best bet. The rest of the rambalings really dont apply for my question. By the way I am a rescue diver on nitrox.

 

[O-ring]

You are looking for overhead training..here are some of the places that provide it:

TDI
IANTD
GUE

 

[Jarhead]

O-ring once bubbled...
You are looking for overhead training..here are some of the places that provide it:

TDI
IANTD
GUE

NSS/CDS

 

[JT2]

There is lots of good reading here on diving with exotic gases.
http://www.techdiver.ws/exotic_gases.shtml

 

[AquaTec]

thanks for the link but i was looking for something on the narcotic effect of oxygen.

got a handle on the rest.

i am looking for scuentific evedence

 

[MikeFerrara]

From memmory...It is thought that the nacotic effect of a gas is related to it's lipid solubility. Based on that O2 should be about twice as narcotic as N2. However, We motabolize O2 so some believe that it's a wash and their about the same. If I was in the shop I could pull some references. Yes there is some theory here and I don't know of any conclusive data.

The thing is this though, as we approach depths where narcosis is more of a factor we are also reaching depths where we can't add much if any extra O2. Therefore, I would have to say that Nitrox is of no use in controling narcosis.

There are two commonly used equations for calculating END. One assumes that O2 is not narcotic the other assumes that it is. In most cases the difference in calculated END is only a few feet. If your planning using a reasonable END I don't think the difference is significant..

For easy penetrations at recreational depths the PADI class may be OK. If your seriouse about wreck penetration get a cave card. Caves and wrecks are not the same but many of the required skills are.

 

[AquaTec]

Let me throw a couple of things at you.

O2 should be about twice as narcotic as N2

If it is twice as narcotic as N2, and you feel the effects of nitrogen 'narcosis" at say 4ata .79% nitrogen at 4ata =3.16ata
1/2 of that being twice as narcotic is coincedently 1.58ata

so if we breath 02 at 100% at 1.58ata which would take place at 20 feet +/- then we would remove the nitrogen and be as narced as air at 100 feet. but we are not, even if we encrease the Po2 of O2 we still do not feel the effects of narcosis.

now the fact that we matabalis it doesn't make a whole lot of since, in simple terms...as i am a simple guy....we also matabalise alcohol...we just convert it to sugar..after it has had its narcotic effect on us.

I have heard this theory before, but it comes from only one source...now they might be on to something, but you would think that with all the research that is being done in hyperbaric medicine right now, some real smart scientist / doctor should also have even a wild theory about this. I have yet to read anything.

I don't say it is not true i would just like to know more about it as i really enjoy oxygen every day

My thought have been higher O2 and higher He at shallower depths for deco reducing the N2 to as much as possible because of the rapid ongassing and offgassing effects of He. finishing off the deco with pure O2 and backswitching to bottom gas throughout the final stages. this assisting in a cleaner dive.

Nitrogen is the enemy, if O2 is as well I would like to know more from many different sources.

maybe the narcotic efects are from the specific gravity of the gas alone, it seems to coincide with how narced you can get from the different gasses. ie argon is twice as narcotic as N2. or that Hydrogen is better than He as far as narcosis.


sorry i have been rambling here.
see what you can do to answered some of my questions barried in my ramblings

 

[CheeseWhiz]

Why not pop on over to Dr. Deco's section of the board and see what he knows?

If he doesn't know the answer to the question of O2 narcosis then I'll be he knows where to find the answer.