air in nitrox tank?

[rds912]

Ok,
After reading alot of threads on this I am still confused. Can a buy a tank and have it serviced for nitro, but then have plain air put in it if there is no nitrox available. Would I have to have it re-serviced before getting a nitrox fill again even if it is premix? Thanks for the help

 

[divad]

Ok,
After reading alot of threads on this I am still confused. Can a buy a tank and have it serviced for nitro, but then have plain air put in it if there is no nitrox available. Would I have to have it re-serviced before getting a nitrox fill again even if it is premix? Thanks for the help

You can put "premix" in anything.

 

[jfoutz]

If the tank is just rated for premix, you can put either air or nitrox in it. Switch back and forth all you want, it doesn't matter.

If the tank is O2 clean for partial pressure nitrox blending, anything you put in it needs to come from an 02 clean compressor. (This can include just putting air in it.) Violate that rule and, until the tank is 02 cleaned again, it's an air or premix only cylinder.


The nice people at Luxfer of course are going to disagree with me, as they explain here:
http://www.luxfercylinders.com/support/faq/aluminumoxygen.shtml
You can take it for what you will, but I'm not buyin it...

 

[lamont]

Ok,
After reading alot of threads on this I am still confused. Can a buy a tank and have it serviced for nitro, but then have plain air put in it if there is no nitrox available. Would I have to have it re-serviced before getting a nitrox fill again even if it is premix? Thanks for the help

You need to read up on "oxygen clean" and "oxygen compatible."

If your tanks are oxygen compatible then they just have viton o-rings and O2 compatible lube. You are not supposed to partial pressure mix into these tanks, since there's a risk of O2 fire. You can put any air or any premix into these tanks that is less than 40% O2. The O2 compatability is not changed by putting in non-hyperfiltered air. Also, even if the tank isn't O2 compatible, you can still put nitrox in the tanks, it'll just attack the O-ring. Personally, I'd make sure the tank had O2 compatbile o-rings and lube -- a bad tank neck o-ring at depth would kinda suck...

If your tanks are oxygen cleaned, then they've been washed of any hydrocarbons that could cause an O2 fire. You can partial pressure fill with 100% O2 into the tanks, and you can store any concentration of nitrox in the tanks. If you put hyperfiltered air into the tanks (EAN21) you will not void the O2 cleaning of the tanks. Many dive shops that don't have nitrox will still have acceptable hyperfiltered air. If you put non-hyperfiltered air into the tanks it will technically void the O2 cleaning and it should be treated as an O2-compatible tank.

The oxy hackers books mentions that in reality a tank is unlikely to lose its O2 clean virginity from a single fill of bad air. It also mentions numerous times that O2 is fickle though and warns not to push it.

 

[mike_s]

Basically, you can put the equivalent of air in your tank, which is 21% Nitrox. (which is the same as air). It's just put in from a "Nitrox" blending panel on the compressor banks. It's still o2 clean.


If you take it to a places that doesn't do Nitrox fills and just has a regular "air" compressor system, then time to have the tanks cleaned again before you put Nitrox in them.

Btw... Most places won't charge you "extra" for a 21% Nitrox(clean air) fill.

 

[Jason B]

Short simple answer and jfoutz said it best. By the way, have you had a nitrox class. I sure would have hoped this would have been covered.

Jason

 

[Dive4Life]

Basically, you can put the equivalent of air in your tank, which is 21% Nitrox. (which is the same as air). It's just put in from a "Nitrox" blending panel on the compressor banks. It's still o2 clean.


If you take it to a places that doesn't do Nitrox fills and just has a regular "air" compressor system, then time to have the tanks cleaned again before you put Nitrox in them.

Btw... Most places won't charge you "extra" for a 21% Nitrox(clean air) fill.

If you have a clean tank you generally want to put in clean air. Clean air being air that is filtered to have less than 0.1 microns of hydrocarbons in it. Any technical diving facility should be able to help you with that. A good question to ask when you fill your tank is, "What kind of compressor? and "What kind of filters/or grade of air are they using?" Grade E air IS NOT GOOD ENOUGH FOR O2 cleaning. Then again, others would argue that your tank could have pure oil in the bottom and have it filled with 100% O2 with no problems. I'm just preaching what I was trained in. From experience not many people have problems with it either way.

 

[OE2X]

Perhaps a more simplified version of the above:
Ask for hyper filtered air for you tank. It is 21% but it goes through and extra filtering stage. Any shop that fills nitrox will have have hyper filtered air. A shop that doesn't fill nitrox is suspect. Using hyper filtered air will not compromise your tanks nitrox rating.

 

[Wijbrandus]

I wonder what kind of a look I'll get if I walk into my LDS and ask for EAN21?

Will I have to pay the nitrox fill rate?

Things that make you go, "Hmm..."

 

[Dive4Life]

Perhaps a more simplified version of the above:
Ask for hyper filtered air for you tank. It is 21% but it goes through and extra filtering stage. Any shop that fills nitrox will have have hyper filtered air. A shop that doesn't fill nitrox is suspect. Using hyper filtered air will not compromise your tanks nitrox rating.

LOL, thats what I was trying to get out. Thanks OE2X :dazzler1: