Nitrox!

[AndyNZ]

Is it possible that while incidences of Type I though IV DCS are equally unlikely with and without Nitrox on "recreational" dives, incidences of sub-clinical DCS are reduced through the use of Nitrox? This could explain why divers report feeling "less tired" after diving Nitrox.

It's possible. But from my own experience, ascent rate is the key factor to fatigue as well. I never notice any discernible difference after diving nitrox than air, but I notice a huge difference in fatigue levels when introduce deep stops and graduated ascents on minimum deco dives.

Of course, when I dive nitrox I tend to push the limits anyway.... if you do 30 mins @ 30m on 32%, you've essentially got the same levels of nitrogen in your tissues as if you'd done 20 mins @ 30m on air.

 

[Dannybot]

I was just wondering, I don't dive nitrox and I was wondering if it's worth it to get it. Everybody says it is, because its safer and you can get more time out of your dives as long as you still manage your air intake. But, How much longer will it let you stay down compared to the normal recreational no decompression limits?

Back to the original question. If you eat up a whole tank using an air NDL model, then there is not likely much advantage to diving NITROX. But if you are pushing NDL's and still have air left at the end of the dive, then maybe. Does your buddy sip air as well? Does the dive operator you are using allow for the extended bottom time? NITROX reduces nitrogen loading, but if you don't have any air in your tank, then what's the use?

Education is always good, learn more, dive more. Good luck.

 

[Monkey_Gland]

I would argue that it's no more dangerous than diving air if you've understood the parameters under which you can use it successfully. Education is probably the key to understanding the bang for buck, so go do the course and come back and tell us we were wrong! Or not

 

[masterof0]

Of course, when I dive nitrox I tend to push the limits anyway.... if you do 30 mins @ 30m on 32%, you've essentially got the same levels of nitrogen in your tissues as if you'd done 20 mins @ 30m on air.

you hit the nail on the head. If you dive the NDL of the mix you are using, your benefits are increased bottom time, but your nitrogen loading will be the same.

if you dive the bottom time based air, your benefit will be decreased nitrogen loading.

ultimately, there is no increased risked of going to nitrox, only perceived benefits. its up to you to decide if the perceived benefits is worth the efforts. Having recently gone through the class, I certainly think so. If for no other reason, it helped be better understand NDL, MODs, PPO2, and nitrogen loading.

 

[Reg Braithwaite]

Of course, when I dive nitrox I tend to push the limits anyway.... if you do 30 mins @ 30m on 32%, you've essentially got the same levels of nitrogen in your tissues as if you'd done 20 mins @ 30m on air.

This agrees with my mental model: One factor is your decompression profile, the other is your nitrogen loading. Nitrox provides lower loading for a given dive, or it provides a longer dive with the same loading. But once loaded, it's up to your decompression profile to reduce sub-clinical DCS or the risk of DCS itself.

Getting back to the OP, my feeling is that on guided group dives with some divers on Nitrox and some on Air, the divers on Air and the wind-sucking pigs are going to limit the dive profile, so reducing consumption and diving Nitrox are going to be wins, since you can't stay in the water longer than the air divers.

That being said, you might end up diving deeper than the folks on Air, so you may give back some of the benefit. Here's my actual advice: Take the course, get the certification. Now you have more knowledge and the ability to choose to dive Nitrox or not. It's another tool in your tool box.

 

[wve]

The benefit of nitrox is to extend your bottom time by reducing nitrogen loading, not to make "dives safer".

I agree that if you are diving Nitrox in order to extend certain limits, then you are trying to achieve a greater result with a degree of risk that equals air.

On the other hand, if you dive the same profile as you would on air while using Nitrox, and if you stay well within the MOD of the mixture, how could reduced nitrogen loading NOT be safer?

Study results can be misleading. Considering the relative infrequency of DCS in the first place, it is easy to imagine that a study comparing divers on Nitrox versus divers on air could be under-powered, lacking enough subjects to be able to detect a statistically significant difference.

A study's inability to demonstrate a difference may be due to a flaw in the study, not the concept of using a gas which contains less nitrogen.

That said, I agree those who advise taking the course. It's fun stuff to talk about. Look at how many replies the original post already generated!

 

[rongoodman]

Where Nitrox really helps is on a liveaboard, where you could be doing 5 dives a day for a week. I think it's worth taking in any event, just for the additional knowledge about gas laws, partial pressures, etc., stuff that isn't always absorbed the first time around.

 

[Blackwood]

wow, this thread exploded.

I'm surprised to see almost 3 full pages with no mention of repetitive dives.

 

[masterof0]

you can dive nitrox using the same diving times as air as long as you don't exceed the MOD of the mixture you are using. By doing this, you reduce the amount of nitrogen loading in the tissue. By using it this way, you are building in an additional safety factor on top of what is built into your diving profile. Also, by doing this, you reduce your SI requirement for successive dives.

Here was a brief comment about repetetive dives....

 

[Steve50]

Believe I mentioned that. The benefit of EAN is to extend RDP bottom times. The safer tagline is used by some instructors to sell courses and by ill-advised divers. Only one case I know of that was a good reason for using EAN other than extended bottom times. I had a student who had an illness that caused a disproportional drop in his oxygen levels with exercise (can`t remember the name of the illness) and managed average dive times when he swapped to EAN. If you`re using EAN as "it`s safer" you are indeed wasting money on fills. Personally no EAN student of mine (except the aforementioned guest) has ever been sold an EAN course with me because "it`s safer".

If reducing nitrogen loading for a given dive does not make it safer - why bother with dive tables or dive planning with regard to nitrogen loading, at all?