Does gas go bad / expire / go stale in a tank?

[KidK9]

Of course I'll check the O2. So how long does anybody think that should be good for? I plan on going to the shop tomorrow to use their analyzer, anybody wanna guess what it'll read??

 

[miketsp]

Being a high grade aluminium alloy cylinder I would expect it to read the same as it did 8 months ago.
The only place for the oxygen to go would be if it could combine with something in the inner surface of the cylinder or in the actual air mixture - oxidation. The inner surface of the cylinder should already have oxidised to its maximum extent before you had it filled and there should be no significant impurities in the nitrox mix.
But you still test with your O2 analyser to make sure.

If it was a steel cylinder with any humidity in the mix then other factors would come into play.
See thread
http://www.scubaboard.com/t57807.html

 

[miketsp]

I gave the answer above because I remember looking into this after my Nitrox course some time ago but then I became curious about O2 PP above 40% so I researched several sites of cylinder manufacturers and medical gas suppliers.
The general opinion from the manufacturers is that compressed medical gas products, including pure O2, do not degrade over time. The only check necessary apart from periodic cylinder structural testing is remaining pressure.

 

[Pierre Siquet]

Do not know what VIP is, but refilling is 8 hours drive from here to go and extra 8 back. But I am going to refill it as I am also going to dive at 8 hours drive.

Cheers

 

[Web Monkey]

VIP = Visual Inspection Program

Someone lets the air out, removes the valve and inspects the inside of the tank for rust, cracks, etc. (or in my case, some type of small mysterious green slimy smear that appeared on the bottom of my pony after a trip to Florida).

Terry

Do not know what VIP is, but refilling is 8 hours drive from here to go and extra 8 back. But I am going to refill it as I am also going to dive at 8 hours drive.

Cheers

 

[Pierre Siquet]

Thanks

 

[Henry]

Do not know what VIP is, but refilling is 8 hours drive from here to go and extra 8 back. But I am going to refill it as I am also going to dive at 8 hours drive.

Cheers

Seriously, move closer to dive shop and dive site. It will make your life easier and I will feel less pain when I read you posts.

Henry

 

[Pierre Siquet]

Seriously, move closer to dive shop and dive site. It will make your life easier and I will feel less pain when I read you posts.

Henry

Yep Henry, I have the same pain than you when I read myself. I will get them inspected and rifilled. Actually, the risk of problem is very low, as Tanks are almost brand new.

Feel released!

 

[Curt Bowen]

Hi all,

Got steel tanks filled now for over a year. Is there any health problem in breathing this air? I know it is recommended to change every 6 months, but why?

Thanks for your ideas.

Pierre

Seems like a lot of talk when its much easier just to drain and refill if your concerned.

 

[Pierre Siquet]

Lots of talk, because the place I can refill is 8 hours drive to go.