Nitrox vs Normal compressed air

[jimdiverman]

Do you have to have seperate tanks for Nitrox and regular compressed air? can they be swapped out pretty easily? Im guessing it makes no difference at all but just want to be sure

Below 40% Nitrox, you can dive with regular tanks that are marked for use with Nitrox, unless the fill station uses partial pressure blending. If they use partial pressure blending, then the cylinder could be in contact with pure oxygen, requiring it to meet oxygen service standards.

There is also a special green and yellow band that goes on the tank. Above 40% O2, you always need an O2 clean tank that is rated for Oxygen service. This is not your standard run-of-the-mill Aluminum 80 that you find at the LDS.

 

[Papa_Bear]

I have more than a thousand dives on Nitrox and have never gotten dry mouth from Nitrox! If your doing more than three dives a day it is the only way to go! I do five or more dives in one day on Nitrox I am up to 11:00pm, but on air I am in bed by 9:00pm! All antidotal but if it's just a placebo I will take it, but I do think it's in your mind Caving wouldn't be what it is without it and if you don't think it makes a deference go caving on air, but bring more air! For me it also improves bottom time and I can prove that based on my computer log!

 

[berick]

All antidotal but if it's just a placebo I will take it. . .

I agree totally (except for the spelling of anecdotal -- unless it was a pun) with the quote above. It may be in my mind, but, I feel better (less tired) on Nitrox on a 20+ dive week and I get less cotton mouth on Nitrox.

 

[BKP]

I usually don't have the luxury to dive five times a day, so while I'm EANx certed, I mostly use just air (unless I specifically know that my planned profile means incurring a restrictive nitrogen loading, deco obligation, or otherwise limit bottom time).

I don't know if Nitrox has a dry-mouth benefit, clinically. I've only experienced an improvement in dry-mouth when I heavily hydrate prior to the dives, regardless of my mix. I've always looked for that mystical fatigue abatement on Nitrox, and have yet to feel it. Perhaps it's individual physiology dependent. I can't comment on that -- I just don't know.

I *do* look forward to the day when my profiles require more frequent Nitrox use (but my company keeps refusing my transfer requests to Belize).

 

[peterbj7]

This is not your standard run-of-the-mill Aluminum 80 that you find at the LDS

Actually it can be just that. Most tanks manufactured these days are recreational nitrox friendly (but not pure oxygen friendly, so you mustn't use them for partial pressure blending).

A special note to the OP - at the age of 12 you're not going to be diving so close to the limits that nitrox will extend your dives (or you shouldn't be!), but doing a nitrox course will if it's a good one teach you a lot about diving in general and make you a better and better informed diver. Actually, as you obviously have an enquiring mind you might like to read up about it by yourself. I'm sure there are general books that you could read, but in terms of course manuals you can't do much better than to get hold of the IANTD Nitrox manual. Way more comprehensive and better written than the PADI effort. And if you find you take that in pretty easily then also get their Advanced Nitrox manual. A lot of that is about equipment handling, but it also goes even more in depth into nitrox theory. Look up their website www.iantd.com.

 

[jimdiverman]

Actually it can be just that. Most tanks manufactured these days are recreational nitrox friendly (but not pure oxygen friendly, so you mustn't use them for partial pressure blending).

Actually Pete, you have contradicted yourself in your quote of what I said. You first imply that a run-of-the-mill tank can be used for oxygen service when you said "Actually it can be just that", and then you say you can't use it for partial pressure blending. Oxygen service is exactly what I was referring to when I was talking about the run-of-the-mill tank at the LDS. It is NOT clean for oxygen service from the factory and NOT maintained for oxygen service by the LDS. Recreational nitrox and oxygen clean are not the same thing. So, ACTUALLY, it ain't just that, and most factory tanks and regulators can't be used for partial pressure blending or oxygen service unless the factory specifically states it. In fact, if the tanks actually were oxygen service from the factory, most would lose their rating the first time they hooked their rental regulators up to it which are not rated for oxygen service because everything you hook up to an oxygen service system including the air, (yes even compressed air must be filtered to remove very small particulate and rated for oxygen service if you use that in the tank) and including the first and second stages must be cleaned for oxygen service and O2 service compatible (Viton o-rings, crysto lube, etc.) in order to maintain that rating, and while some shops, mainly tech shops, keep some equipment for this sole purpose, the run-of-the-mill tank, 1st stage regulator, and 2nd stage regulator is not only not cleaned for oxygen service from the factory, they aren't O2 service compatible to begin with. And most honest shops will tell you when their gas isn't up to snuff either and you want to use it in your O2 clean system that you paid to have cleaned. And if they are using partial pressure blending at their shop (instead of banking 32% or 36%), and not requiring systems be O2 service compatible and O2 clean to fill, then shame on them.

 

[BarryNL]

Actually it can be just that. Most tanks manufactured these days are recreational nitrox friendly (but not pure oxygen friendly, so you mustn't use them for partial pressure blending).

Just to add, it's not really the tank that is the critical component but the valve. When oxygen filling it's the valve parts which are subjected to high temperatures due to adiabatic compression and most sensitive to hydrocarbon contamination. When I'm oxygen cleaning my valves I don't even touch the parts unless I'm wearing latex gloves - even the oils on your skin can be enough to cause a fire.

 

[stairman]

I seem to be less fatiged after diving nitrox.As far as the dry mouth it seems the same,I dont get it with either because I hydrate like crazy before a dive.I would incorporate a nitrox class with your advanced o.w diver course.My daughter was certified at 12 also.[scuba steph]and is taking intro cave next month.Continuing education is important.The more you know the better youll be.Good luck!

 

[Tomeck]

I use air, because I often dive on 200 feet and I am afraid of hyperoxy. If up to 130 feet, it is a good idea to use nitrox.

 

[peterbj7]

Jim - I just tried to check back to your original post and I can't find it! So I can't now be sure what you said, but I don't disagree with anything you say in your latest post.

To pick up on what BarryNL says about high temperatures, I was astonished to read that the temperature at the end of the debris tube (protruding into the tank from the valve) can reach 3000 degrees celcius if the tank is filled as fast as many fills stations do. IANTD have it that a tank should be filled at 4-7 bar/minute to avoid high temperatures, which is greatly slower than anyone I know does.

Tomeck - no-one would choose to use nitrox for those dives, but what about subsequent shallower ones?