Air and nitrox life?

[bazzurco]

How long can you store a full tank of air or nitrox in a steel tank before it goes bad? I know from experience if air gets too old it can develope a bad ordor. I have quite a few tanks and don't mark the fill date like I should. Recently I started to use nitrox once in awhile and was wondering about shelf life.

Thanks for your help.

 

[Jonathan]

interesting question - I've just checked in as I'd like to know the answer to that too.....

I know you mustn't store tanks empty but that's about it on that front....

Jonathan

 

[Compressor]

Don't think it matters much. Unless there is rust in the tank in which case the oxygen level may drop as a function of the rust. In reality when you to have to VIP your tank, they will have to empty the tank and thus it becomes a non issue.

 

[Rick Murchison]

A rule of thumb is a year. However, there has been at least one case of a steel tank with moisture in it that had enough oxidation to lower the oxygen content to the point that the diver passed out and drowned in a pond.
This was a very unusual case in that it took a special combination of long storage, moisture in the tank and pretty low pressure (with a full tank the tank would likely fail before oxidation could reduce the amount of oxygen to dangerous levels).
Anyway - fills are cheap - if it's been sitting for a year go ahead and get a VIP and fill before using it.
Rick

 

[Jonathan]

I seem to remember reading somewhere that storing oxygen or high percentage O2 nitrox was bad for the tanks - or was I just dreaming?

Not much of an issue for me as in Japan it is very unusual to own your own tanks and getting nitrox of any sort is not easy for a non native like myself (i.e. don't speak the lingo yet....)

Cheers
Jonathan