Does tank air go bad?

[UnderSeaBumbleBee]

I was in the LDS the other day and over heard the lds owner tell another diver that he needed open the valve to drain his tanks and bring them in for refill. They were full, but the air had been sitting in the for a year. The LDS owner said you never want to breathe old air, always fresh.

So is that true or was the owner just trying to get they guy back in the shop?
Thanks,
Leah

 

[do it easy]

After a year, I think it would be a good idea to VIP the tank to check the condition on the inside. The air would probably be fine, although I would be too paranoid to use it.

 

[wallacm]

The air is prolly good but i agree with Do It Easy. I know i have used air thats about 2 months old, dont try to go anymore than that.

 

[Scuba Sciences]

Hi,

I have come across this problem a few times when a cylinder has sat in the garage or home for a long time, I have definitely smelled some stale and bad air. I had a cylinder one time that had rust inside and another with oil inside (from an airfill in Mexico) that smelled really bad.

The cylinder should be annually inspected anyway, it is drained for that process, then refilled with clean air once it passes the VIP.

I hope this helps!

Tina
Scuba Sciences, Inc.
www.scubasciences.com

 

[miketsp]

It is generally accepted that compressed gases are good for a lifetime.
The only exception would be a possible O2 reduction due to internal oxidation of a steel cylinder filled with damp air.
So provided the cylinder is not so old there's a VIP problem, if it's AL just use it, if it's steel just put an O2 analyser on it.

 

[LOOPS]

Just as a normal rule... all tanks are to be VIP every year and hydro tested every 5 years. So if the air has been in there for a year or more it is old and the tank does need to be visually inspected. I would never use air that has been in a tank for an extended amount of time. When renting a tank always make sure the visual has been done in the past year and the hydro is up to date. Especially if you are renting the tank for a few days and having it filled elsewhere... otherwise the tank will not be refilled by another location if it is not up to date. Hope this helps!

Cheers!

 

[markfm]

If you have any E7-100s, just send them to me, I'll take care of the air