Oxygen narcotic?

[rjack321]

I guess my real question is, if oxygen is narcotic, why is there no discussion about it when talking about accelerated deco? Or is it not a significant factor when shallow? And if it isn't a significant factor when shallow, why should it be an issue at depth?

Have you ever heard someone complain or discuss major narcosis at 20ft no matter what the breathing gas?

Narcosis doesn't factor into even the most conservative dive planning at 0-90ft(ish) depth. Very few divers are doing deco deeper than that so until you start doing 250-300ft dives and starting your deco below 100ft its not an issue.

 

[uncfnp]

Have you ever heard someone complain or discuss major narcosis at 20ft no matter what the breathing gas?

Narcosis doesn't factor into even the most conservative dive planning at 0-90ft(ish) depth. Very few divers are doing deco deeper than that so until you start doing 250-300ft dives and starting your deco below 100ft its not an issue.

Its not about depth. Its the partial pressure. Deco O2 is commonly done at 1.6. So I think his point is why don’t deco divers commonly experienced narcosis if O2 is as narcotic as some seem to think, despite evidence and expert opinion to the contrary.

 

[Storker]

Its not about depth. Its the partial pressure. Deco O2 is commonly done at 1.6. So I think his point is why don’t deco divers commonly experienced narcosis if O2 is as narcotic as some seem to think, despite evidence and expert opinion to the contrary.

1.6 bar PO2 is 6m (1.6 ATA) with 100%. With 50% it's 21m (3.1 ATA). Even if O2 were somewhat more narcotic than N2 (as one would expect from Meyer-Overton), 3.1 ATA is well below the 4-5 ATA where narcosis usually is noticed.

So while it's about partial pressure, pP and depth are pretty well correlated unless you start putting He in the mix.

 

[cerich]

1.6 bar PO2 is 6m (1.6 ATA) with 100%. With 50% it's 21m (3.1 ATA). Even if O2 were somewhat more narcotic than N2 (as one would expect from Meyer-Overton), 3.1 ATA is well below the 4-5 ATA where narcosis usually is noticed.

So while it's about partial pressure, pP and depth are pretty well correlated unless you start putting He in the mix.

hydrogen is explosive choice as well.
in fact, back in 60's-70's there was some comex hydrogen based diving going on (Hydrox)
Diving with Hydrogen – It’s a Gas

There is the "bonus" that hydrogen narcosis is like a lsd trip

 

[Storker]

There is the "bonus" that hydrogen narcosis is like a lsd trip

I think I'll avoid hydrox.

 

[cerich]

I think I'll avoid hydrox.

meanwhile in Georgia I am writing out a new instructor specified specialty course where strobes are used, not as navigation or anything but for additional atmosphere.

 

[Storker]

meanwhile in Georgia I am writing out a new instructor specified specialty course where strobes are used, not as navigation or anything but for additional atmosphere.

Seizure specialty?

 

[rjack321]

Its not about depth. Its the partial pressure. Deco O2 is commonly done at 1.6. So I think his point is why don’t deco divers commonly experienced narcosis if O2 is as narcotic as some seem to think, despite evidence and expert opinion to the contrary.

O2 would have to be radically different than N2 for you to notice or measure at 20ft. Nobody is saying its radically different. Its generally treated as roughly equal to O2. That's why there's no measurable different in narcosis where the vast majority of deco is done.

1.6 bar PO2 is 6m (1.6 ATA) with 100%. With 50% it's 21m (3.1 ATA). Even if O2 were somewhat more narcotic than N2 (as one would expect from Meyer-Overton), 3.1 ATA is well below the 4-5 ATA where narcosis usually is noticed.

So while it's about partial pressure, pP and depth are pretty well correlated unless you start putting He in the mix.

plus what he said ^^^

 

[cerich]

Seizure specialty?

Quadmix 200m

 

[Storker]

Quadmix

And the fourth gas is...? H2?

Not that I'm ever gonna take that specialty, it's purely intellectual (AKA geeky) curiosity.