Nitrox vs Air

[SilverNU]

I plan on getting my Nitrox certification.. was wondering what the main differences were between Nitrox (mixes) and a regular tank of Air.

What will it let me do that air lack? etc etc

 

[Thalassamania]

EAN has more oxygen than air, this lowers your nitrogen uptake for a given pressure exposure. The price that you pay, on the other end, is a depth limitation due to danger of breathing high partial pressure oxygen and (less often) a time limit for the same reason.

 

[SilverNU]

so.. at 100ft EAS would increase your bottom time?

 

[drdaddy]

Yes, but ... there are some very definite limitations and even dangers. You need the class to know about the great advantages and limitations. Nitrox is just another tool to be used in the enjoyment of diving. I use it infrequently, but when one wants it - it's nice to have.

About increasing your bottom time, possibly (depending on your air supply), but most likely the advantage is that you would need less surface time (releasing nitrogen) between dives to keep you from your "No Decompression Limit".

 

[MuddyRubberDuck]

so.. at 100ft EAS would increase your bottom time?

Yes. You are adding oxygen which displace some nitrogen. Nitrogen loading is what determines your ndl. Less nitrogen means longer ndl times. Sorry for the half ass response but I'm tired. Lol

 

[sardiverdan]

Yes it would but not by that much. The issue here is also what tables you are going to use. Some are a little more forgiving than others. Lets say 100 FSW on air is 20 min NDL while EAN 32 may be 25 min NDL. EAN really shines in the shallower depths. 60 FSW on air is about 60 min NDL (Navy tables) while EAN 32 my be between 75-90, again depending upon what tables you are using. Like Thalassamania pointed out. The depth limit of EAN can be a real concern. EAN 32 has a max depth of 130; however at that depth you are around 1.58 PPO2 and many people I know try to keep their PPO2 around the 1.4 range so a dive to 130 would be better on EAN 28 vice EAN 32.

 

[gcbryan]

I plan on getting my Nitrox certification.. was wondering what the main differences were between Nitrox (mixes) and a regular tank of Air.

What will it let me do that air lack? etc etc

It will extend your NDL times or reduce your surface intervals. It may or may not extend your actual dive. As a new diver if you are running out of "gas" before you reach your current NDL then using Nitrox will not result in a dive that is any longer.

It also generally will cost more to fill your tank and may mean that you need to get your tank cleaned to a different standard than required for standard air and may mean that you can't use standard air in your Nitrox tanks. It depends on the shop and how they do their fills.

 

[DandyDon]

EAS...?

Yes it would but not by that much. The issue here is also what tables you are going to use. Some are a little more forgiving than others. Lets say 100 FSW on air is 20 min NDL while EAN 32 may be 25 min NDL. EAN really shines in the shallower depths. 60 FSW on air is about 60 min NDL (Navy tables) while EAN 32 my be between 75-90, again depending upon what tables you are using. Like Thalassamania pointed out. The depth limit of EAN can be a real concern. EAN 32 has a max depth of 130; however at that depth you are around 1.58 PPO2 and many people I know try to keep their PPO2 around the 1.4 range so a dive to 130 would be better on EAN 28 vice EAN 32.

..."not by that much." Yeah, the dive plan will vary with which tables or computer one uses, but I generally expect 50% more NDL time on 32% Nitrox. Using the common Padi tables, the differences at 100 ft are 20 vs 30 min; at 60 ft - 55 vs 90 min, or 115 min on 36%. Even tho many new divers run low on air before they hit NDLs, it's still preferable to not push NDLs anyway.

You really want to get your Nitrox card before driving down to NC to dive the wrecks. The charters will take air divers to them, but cutting your NDL by 33% is tough, and finding another air diver to buddy with is challenging, but it's unfair to a buddy on Nitrox to quit when you need to. Been thru that.

The vast majority of charters I've dived with on various trips furnished Nitrox pre-bleneded so even if I could have taken my own tank, it wouldn't have matter. There are certainly exceptions. If you fly out west, I don't think you'll find it a common option in CA or Seattle. I didn't.

 

[sam1]

The graph from a previous post of mine shows an example of depth ranges, NDLs (PADI), and air consumption constraint. http://www.scubaboard.com/forums/4474187-post129.html

FWIW I use Nitrox on virtually all dives, not to extend bottom times but to add a margin of safety.

 

[String]

I plan on getting my Nitrox certification.. was wondering what the main differences were between Nitrox (mixes) and a regular tank of Air.

What will it let me do that air lack? etc etc

Well you have a shallower maximum depth. Your NDL for a certain depth range is increased vs air. It often costs 2-3x that of an air fill.

If you're ending dives because you're running up to a NDL as opposed to a time or air limit then nitrox is useful. If you're not ending dives due to NDL limits it won't be.
For open water level dives that are 18m max its almost certainly air consumption not NDL limiting the dives.

FWIW I use Nitrox on virtually all dives, not to extend bottom times but to add a margin of safety.

and your referenced source to back this claim up is where exactly?