Converting tanks to Nitrox

[The Chairman]

Originally posted by pescador775
Boy, that's a pain, but it makes sense. Bit' by the Vyper. Thanks.

Actually,

I dive the Cobra and the default mode for me is NitrOx at 21%. All I have to do is set the % of O2 and I am off. If I am diving air, no change is needed. If I decide to dive 32% on the next dive, it won't lock me out for a day.

 

[Garfish]

i"ll agree with Net Dock. My computer operates in the same respect.
As for having my own tank o2 cleaned, i have gone that route.
It didn't cost me that much to have it changed over and i have the convenience to use EAN 32 or 36 or Nitrox cleaned compatible air.
As for having my tank filled, i'm very particular who gives me a refill. I try to stay with my LDS if possible .
As for the price is concerned , i don't mind paying the extra 5 bucks for Nitrox. It's nice to have the best of both worlds.

 

[BEM]

Oops! No, I didn't check to see if the BC was Nitrox compatible, had to re-read my post to see if I said "BC" - I did! - but I wouldn't be surprized if Mares said that it was (somewhere in their literature.)

As an aside, do you Nitox divers, who use pony tanks, also fill them with Nitrox?

 

[WreckWriter]

Originally posted by BEM
Oops! No, I didn't check to see if the BC was Nitrox compatible, had to re-read my post to see if I said "BC" - I did! - but I wouldn't be surprized if Mares said that it was (somewhere in their literature.)

As an aside, do you Nitox divers, who use pony tanks, also fill them with Nitrox?

Good! The oxygen cleaning thing really doesn't get critical until you go over 50%, even then you only really need it in your regs. Never heard of an O2 clean BC! (although if it was as critical as some folks think we'd have to, wouldn't we?)

As for the pony question, yea, if you're diving nitrox always, I'd say fill your pony with same. Again, its not critical in my opinion.

Tom

 

[Ontario Diver]

If you are diving Nitrox, a popular method is partial pressure blending. Using this method - pure O2 is pumped into your tank first and then air is added.

If your shop uses this method (and all of those I've seen in Ontario do!!!) your tank and yoke must be O2 Cleaned and serviced (because it is exposed to 99.lots % O2). In fact, they shouldn't even do it unless your VIS states that the tank is O2 ready.

 

[Ron Brandt]

How many on this discussion have Blender Credientials ? Credientals from an original tech agency and not PADI .

It seems that no one on here has actually explained how to "02 Clean",what has to be done and what is involved.

I have a line on some nitrox snorkels if anyone is interested


Ron

 

[Drew Sailbum]

As one who does have a blender ticket, I wouldn't fill a tank with nitrox unless it had been O2 cleaned. If the tank is properly handled, the cleaning is a one time process.

Proper handling includes only filling off hyper-filtered compressors so as not to introduce organic contaminants into the cyclinder.

Some manufacturers ship new tanks in an O2 clean state. So long as the valve is properly prepared (viton o-rings and such), a new setup may not require cleaning.

Similarly, some regulator manufacturers are using Christolube and O2 compatible materials so that new regs are O2 clean from the start.


Flash fires involving nitrox fills are extremely rare. The only instance I am aware of involved an 80% fill in a tank that was not O2 clean. Risks may be lower with reduced O2 percentages, but I'll stick with the cleaning.

 

[Ron Brandt]

You made that short and sweet , I just could not do that

Hyperfiltered air ? The only time I think it would not be hyperfiltered would come from a "backyard" fill with a very old and non maintained compressor.

I have done location fills with a portable compressor for years. PP blending , made to order , on site . Even 18/36 .

Ron

 

[jonnythan]

Originally posted by WreckWriter
In a perfect world it would be no problem to invest a ton of money getting everything you own oxygen cleaned and it would make a discernable difference. In reality though, for the low percentage nitrox you're talking about, you likely won't even notice an increase in the life of your o-rings. A safety benefit? I doubt it.

Again, in my opinion only, for low level nitrox, a cool green sticker will do the trick.

Tom

ps- You didn't really check to see if your BC was nitrox compatible, did you?

The issue is that at many shops Nitrox tanks are filled to several hundred psi with pure oxygen. That's corrosive and combustible. I'd be concerned if any of the gear I used, including BC, were regularly exposed to pure O2, much more so when exposed to 400 psi of it.

 

[WreckWriter]

Originally posted by jonnythan
The issue is that at many shops Nitrox tanks are filled to several hundred psi with pure oxygen. That's corrosive and combustible. I'd be concerned if any of the gear I used, including BC, were regularly exposed to pure O2, much more so when exposed to 400 psi of it.

And how long is that oxygen pure in your tank? Is it EVER pure anywhere other than in your tank? Is 40% EANx more corrosive than air? Likely not much.

That negates the corrosive factor. As for it being combustible, not exactly..... Pure O2 in a clean environment will not burn. What it does is make combustible materials burn much better. In a welding class the instructor may take a tiny dab of grease and direct a stream of O2 onto it. The grease will catch fire, the fire will not run up the stream of O2. The O2 isn't burning, the grease is.

Hopefully you are keeping your scuba gear away from oil and other petroleum products anyway, aren't you? (this includes having your tanks filled only from well maintained compressors)

OK, it is definately better to have tanks oxygen cleaned and to use viton o-rings. For standards EANx mixtures I just don't think it's terribly critical. You certainly don't need to be concerned about your BC....

Tom