50 replies to this topic

[echo3]

I'm looking for a new reg. and before I do, I'm trying to do a bit of homework.

I'd like to eventually try nitrox.

any FAQ/must read references on nitrox equipment?

do most people have a dedicated setup for nitrox or is there gear that will do both?
(I"m thinking once you have your gear set up for nitrox, you wouldn't want to use it for regular air at the risk of contaminating it.)

any guidance you can provide would be greatly appreciated.

thanks

[annasea]

Good question! (I'm hoping to do a Nitrox course during my next trip so I look forward to people's input here.)

[timalso]

Iwould say that 99% of all regs made today are totally interchangeable between nitrox and air and there is no possable way of damaging the equipment by changeing back and forth between the two. There are depth limits in diveing with nitrox. so if your going beyond 110ft. you will want to be diveing with air not nitrox. there may be other cituations where you will not want to use nitrox and there may be a cituation where you travel that nitrox may not be available. your LDS will confirm this when selling you equipment. I did my nitrox cert dives with five year old set of regs there isnt much of a concern here. Tim

[cmt489]

My understanding is the same as Tim's. The reg is interchangeable between the two. I have never had any issues with mine. Where you will want to take future diving plans into consideration will be with your computer purchase. If you plan on diving Nitrox you will want a computer that is capable of both air and Nitrox otherwise you will just be purchasing a second computer in the future.

[PerroneFord]

Hmmmm,

So can't use nitrox below 110 eh? Alrighty.

Might want to be cautious using those titanium regs around enriched air nitrox, they don't mix well at ALL.

[annasea]

What's the deal with Nitrox regarding deeper depths? I haven't paid too much attention to Nitrox up to this point, but I was under the impression that Nitrox was for dive depths of greater than 60' but not much deeper, i.e. 100'+. Why is it *recommended* to not use Nitrox for deep dives? Or, what happens if you do use Nitrox for depths greater than 110'?

[cmt489]

The reason for not going deeper is that oxygen becomes toxic at certain levels. Given that Nitrox has an enriched level of oxygen, as you go deeper, the amount of actual oxygen that you take in with every breath increases. While oxygen toxicity will not kill you, the problem is that it can render you unconcious which, of course, is not a desirable trait underwater...

This is also why the depth you can go on Nitrox varies depending on the blend.

[PerroneFord]

CMT489 is being kind...

It would be nice if the overdoes of oxygen simply rendered you unconscious. Carbon dioxide does that. Nice and peaceful..

CONVENTID is a word you'll hopefully hear in Nitrox class and its a shortened word that describes what happens in an oxygen toxicity event. The CONV portion at the beginning of that word stands for convulsion. Because that is what happens. You'll convulse, spit out your reg, may swallow your tongue, and eventually drown. Ugly stuff.

So, be careful the mix you use when you dive nitrox. And yes, it can be taken below 100 or even 110ft. I dove nitrox on the Oriskany at nearly 125ft, and could have gone to the deck at 135.

As you'll learn in your nitrox class, be DARN SURE, you know what's in your tanks. Analyzing the gas in your tanks is crucial. Marking your tanks properly is also crucial. If anyone tells you that these two steps can safely be ignored, RUN from them. Check the mix. EVERY time.

[Capn Jack]

any FAQ/must read references on nitrox equipment?

do most people have a dedicated setup for nitrox or is there gear that will do both?
(I"m thinking once you have your gear set up for nitrox, you wouldn't want to use it for regular air at the risk of contaminating it.)

any guidance you can provide would be greatly appreciated.

Good questions - as far as training goes - I think you've heard the message - go get some.

For your equipment - the simple answer is recreational nitrox (i.e. less than 40% O2) can be used on virtually any non-titanium reg. There are as Perrone stated, some issues around Titanium you should really understand before making that investment decision.

Higher concentrations of O2 require regs (and all of your other stuff attached to your 1st stage) that are "O2 clean" which means all of the components are safe in a pure O2 environment - this means an exceptionally thorough overhaul and cleaning, with O2 compatible o-rings and grease. I think there may be gear on the market that is O2 safe out of the box, but everyone I know who has gone down this road started by overhauling their current gear.

You can switch between air and nitrox mixes without worry about "contaminating" your gear, it's not the air that will contaminate, it would be the introduction of a non-O2 compatible grease, a replacement o-ring or a flammable contaminant.

You should focus on buying a reg that will serve your needs - now and in the future. If you're attracted to technical diving, ice diving, caving etc. you'll need to work with some of the experts to carefully choose based on the demands of those environments.

Edited by Capn Jack, 27 February 2007 - 05:55 AM.

[Moose]

As you'll learn in your nitrox class, be DARN SURE, you know what's in your tanks. Analyzing the gas in your tanks is crucial. Marking your tanks properly is also crucial. If anyone tells you that these two steps can safely be ignored, RUN from them. Check the mix. EVERY time.

If your nitrox class teaches you NOTHING but the point that PerroneFord made, you are fine!

This is the MOST important part of Nitrox. In fact, my dive center (and I'm sure others) will NOT label a nitrox tank. When you come to pick it up, they MAKE you analsys the mix yourself. Then you mark the tank in front of them and sign a log book. It's a great practice. Of course, only the Nitrox certified diver actually using the tank can pick them up from the shop.

[echo3]

thanks for the replies.

most of the pre-post reading I did was reinforced here (dive levels, % mix and Verification being #1)

I didn't see too much info about the hardware part.

so I'm understanding that as long as the 1st stage is compatable with nitrox and your equipment is maintained accordingly, it should be a non issue changing back and forth between it and regular air. (?)

are there any precautions on the 2nd, octo, bcd & spg ?



my computer will already do nitrox

[matts1w]

As far as "recreational nitrox" (for lack of a better term) i.e. mixes 40% and lower, any reg set made in the last few years is fine...including the 1st stage, both 2nd stages, spg, hoses, as well as you BCD. You may want to check with the retailer as perscribed in many nitrox textbooks, but no worries.

Going back and forth between air and nitrox is a non issue too.

Edited by matts1w, 27 February 2007 - 08:18 AM.

[shadragon]

As far as "recreational nitrox" (for lack of a better term) i.e. mixes 40% and lower, any reg set made in the last few years is fine...including the 1st stage, both 2nd stages, spg, hoses, as well as you BCD. You may want to check with the retailer as perscribed in many nitrox textbooks, but no worries.

Going back and forth between air and nitrox is a non issue too.

When I was looking at equipment I looked to make sure they were EAN 40 compatible as I wanted to go that path (and did). I did find gear that was not nitrox compatible. You have to read the specs on the models you are looking at to make sure they do allow it. Some equipment manufacturers specify NOT to use >21% in the small print or your warranty is voided. Same goes for all your gear that uses HP or LP air.

Knowing the limits of your gear before you get wet will ensure a safer dive. Waiting until you are at 80 feet before finding out something does not work is not recommended.

[Cold_H2O]

If you own your own tanks and are planning on using them for Nitrox.
They must be O2 cleaned.
If your LDS blends while filling it is not a problem.
Some shops do this MOST shops DO NOT ~ So to get a Nitrox fill you must have dedicated Nitrox tanks... Cleaned and stickered.[i]
Most shops put the Oxygen in first and that requires a cleaned tank and compatible O-rings.

I have never had a problem switching between air and Nitrox with my regs.

It has already been stated but let me repeat the information (Perrone you are fabulous )
Nitrox is NOT for every dive. If you are going deep you might want to consider a different gas mix.
Most important thing is to check the mix yourself.
Then you can calculate your max depth for each tank.
You must remember to check each tank.
Just because they were filled at the same time does not mean they have the same blend.
I stick a piece of duct tape on the tank.
Write the date, mix % and the max depth right on the tape with a sharpie....I even initial it to remind myself that I checked it myself.
That way when I get to the dive site ~ there is no question of which tank was 32% and which was 34%.

If you are planning on diving Nitrox the class is a MUST do.

Edited by gis_gal, 27 February 2007 - 09:03 AM.

[matts1w]

When I was looking at equipment I looked to make sure they were EAN 40 compatible as I wanted to go that path (and did). I did find gear that was not nitrox compatible. You have to read the specs on the models you are looking at to make sure they do allow it. Some equipment manufacturers specify NOT to use >21% in the small print or your warranty is voided. Same goes for all your gear that uses HP or LP air.

Knowing the limits of your gear before you get wet will ensure a safer dive. Waiting until you are at 80 feet before finding out something does not work is not recommended.

I would be interested to see who is voiding their warrenty when using nitrox with their gear.