Nitrox vs. Regular Air?

[Blackwood]

No its not. You're assuming that tissues react in a simplistic way. The benefit if any maybe a lot lower than logic would dictate. Real life effects can be so small as to be insignificant or masked by many other factors.

I don't claim to know anything about how tissues react.

 

[texdiveguy]

Nitrox is a wonderful breathing gas for many profiles within recreational diving, and a great deco gas for moderate and shallow decompression.

I did not take the time to read this entire thread so not sure were folks are in a discussion, just thought I would voice an opinion on nitrox.

Air also is great as well as trimix.

 

[MikeFerrara]

What follows on paper isnt always what actually happens in the real world. The change if any at all was found to be statistically insignificant on the only large scale study into determining if diving nitrox on air tables reduced the risk of DCS. Real world tissues may not obey tissues and just because something seems "obvious" on paper doesn't mean it is in reality.

Taking a look at limit conditions is often a good way to get a feel for the mechanics.

While, the statistical advantage of lowering a risk that is already very low may seem insignificant, that can be decieving. You would need a huge number of samples to prove anything. You see? If virtually nobody gets bent diving air to an air table and nobody gets bent diving nitrox to an air table, you didn't demonstrate anything.

Try diving EAN36 NDL's using air and see what happens...or noting that we use O2 enriched mixtures to cut our deompression time to a small fraction of what they would be on air, try those short decompression schedules on air and see what happens.

Sorry, all else being equal, less inert gas means a lower risk of decompression sickness and we prove it all the time.

 

[espenskogen]

Why would someone deco out on 18/40???? That would be absurd.

That was in response to your post that Trimix had all the benefits, but none of the disadvantages.

Nitrox? Why the heck would anyone want to dive Nitrox for? Trimix is where it's at. All the advantages of Nitrox without all the narcosis.

The point is that whilst diving nitrox gives you a longer NDL at a give depth, trimix does quite the opposite, but it eliminates narcosis.

So in other words Trimix is a solution to a different problem. To mix it into the NDL discussion and benefits of Nitrox is the absurd bit. Divers who are unfamiliar with mixed gas diving might actually believe that Trimix is the rage for recreational no-stop diving.

So in response to your question - Nobody in their right mind would attempt to deco on 18/40 - That'd be crazy. But so would using trimix for recreational depths to extend your no-decompression limit.

So there.

 

[ianr33]

That was in response to your post that Trimix had all the benefits, but none of the disadvantages.



The point is that whilst diving nitrox gives you a longer NDL at a give depth, trimix does quite the opposite, but it eliminates narcosis.

So in other words Trimix is a solution to a different problem. To mix it into the NDL discussion and benefits of Nitrox is the absurd bit. Divers who are unfamiliar with mixed gas diving might actually believe that Trimix is the rage for recreational no-stop diving.

So in response to your question - Nobody in their right mind would attempt to deco on 18/40 - That'd be crazy. But so would using trimix for recreational depths to extend your no-decompression limit.

So there.

Errr........ Its still trimix if it has more than 21% O2 in it.

The NDL of 30/30 is more than the NDL of air.

So there back at you

 

[espenskogen]

Errr........ Its still trimix if it has more than 21% O2 in it.

The NDL of 30/30 is more than the NDL of air.

So there back at you

Yes, that is correct, but why would anyone want to dive 30/30? Just to burn some extra money on gas?

I guess if you REALLY hated narcosis, then you could potentially get some benefit out of it..

It's true that the NDL of 30/30 is more than air, but if you compare it to EAN30, it's pretty close. Strictly speaking 30/30 is considered Triox not trimix, but it's close enough I guess.

You have some advantage of the helium when you're decoing - Offgassing is slightly faster, but you are more exposed to injuries should you have a rapid ascents etc with Helium, so buoyancy control becomes considerably more important on trimix.

When it comes to costs however... To fill a 12 liter cylinder (in Egypt) with 30/30 would set you back £39 - Or roughly $78 accross the pond.

The same cylinder with EAN30 would cost you £4 - or $8.

So the question is: Are you LOADED!??

E

 

[TSandM]

30/30 at 100 fsw is probably of dubious benefit. Even for me, and I've had significant narcosis problems at that depth in the past, and I can afford the mix. This is the big argument about recreational triox; enough O2 in it to extend NDLs and you are looking at shallow depths, but lower O2 levels mean pretty brief stays where it's deep enough for the helium to make a big difference. What it all boils down to is that Mike Ferrara is right (as he so often is) when he says that dives in the deeper recreational range are just better planned and executed as mandatory decompression dives (for those with appropriate training, of course . . .)

 

[ianr33]

Yes, that is correct, but why would anyone want to dive 30/30? Just to burn some extra money on gas?

It's true that the NDL of 30/30 is more than air, but if you compare it to EAN30, it's pretty close. Strictly speaking 30/30 is considered Triox not trimix, but it's close enough I guess.

When it comes to costs however... To fill a 12 liter cylinder (in Egypt) with 30/30 would set you back £39 - Or roughly $78 accross the pond.

The same cylinder with EAN30 would cost you £4 - or $8.

So the question is: Are you LOADED!??

E

The cost of a dive should never be a factor! Either Do It Right or dont do it at all !! If you go deeper than 100 feet on air you're gonna die !!!

(Heck,who am I kidding ! I was just pointing out that He mixes do not neccesarily have shorter NDL's than air )

And whats with all the names for Trimix? If it contains He,O2 and N2 then its trimix as far as I am concerned. (I only have a trimix card,am I allowed to dive triox or do I have to pay for another course first?? )

 

[texdiveguy]

Strictly speaking 30/30 is considered Triox not trimix, but it's close enough I guess.

'Triox' is just another coined name for hyperoxic trimix.

Don't need that whimpy mix myself......

 

[Blackwood]

And whats with all the names for Trimix? If it contains He,O2 and N2 then its trimix as far as I am concerned. (I only have a trimix card,am I allowed to dive triox or do I have to pay for another course first?? )

I agree. I call it all trimix.

It seems that names like Triox and Helitrox were coined by training agencies simply to differentiate themselves from other agencies. "IANTD calls this Trimix, so we should call it TriOx. "GUE calls this TriOx, so we should call it Helitrox." "NAUI calls this Helitrox, so" blah blah blah.



If you are full trimix certified, you can get normoxic or hyperoxic blends. However, the opposite isn't always true. Someone who is certified for recreational trimix can't necessarily get 10/70.