How to store filled scuba tanks

[Mopey]

Hello, we have four tanks which were filled four years ago and now sit in a non-climate controlled storage unit.
Real cold. Awful barren ugly freezing bitter cold.
They are aluminum and purchased 2009 and 2012.
Is it safe to store them this way and should I remove some air?
Thanks in advance.

 

[macado]

They can be stored full or almost empty. For aluminum I'd almost recommend nearly empty but it shouldn't matter too much. They're going to need a new visual inspections (and probably hydros anyway) so they'll need to be drained before re-filling/inspected.

I've always been told storing tanks half-full or partially full can be dangerous in the event of a fire. The pressure would increase substantially and the burst disks may not release beforee the tank ruptures.

 

[flots am]

Hello, we have four tanks which were filled four years ago and now sit in a non-climate controlled storage unit.
Real cold. Awful barren ugly freezing bitter cold.
They are aluminum and purchased 2009 and 2012.
Is it safe to store them this way and should I remove some air?
Thanks in advance.

If I had to guess, I'd say they're already empty. The valves tend to leak when cooled.

However if they're not already empty, draining them is safer in case one of them has developed an undetected flaw.

If you're looking for an actual pressure, the DOT considers them non-hazardous if they're drained down to 40PSI.

flots.

 

[kombiguy]

I've always been told storing tanks half-full or partially full can be dangerous in the event of a fire. The pressure would increase substantially and the burst disks may not release beforee the tank ruptures.

I can't even imagine a scenario where an aluminum tank would rupture before an ultra-thin copper disk.

 

[SubAquatix]

I can't even imagine a scenario where an aluminum tank would rupture before an ultra-thin copper disk.

They used to say that about Aluminum tanks in 1989, too!! LOL

 

[flots am]

I can't even imagine a scenario where an aluminum tank would rupture before an ultra-thin copper disk.

You know what's weaker than a burst disk?

The last few thousandths of an inch of aluminum and paint covering up a neck crack.

Especially when the tank hasn't been emptied or inspected in years.

There's a reason it's called "Sustained Load Cracking"

flots

 

[Octopusprime]

Keep them full.... They will lose pressure over time... If they get empty there is a posibility to get humidity in them and moisture can cause oxidation then tanks will not pass vis. I never store a tank with less than 1000 psi. Over the winter a tank can go from 3000psi to 2200 psi. If you start at 1000 psi and it looses pressure and your at 200 psi for a long time tanks will prob have humidity in it.

ues the tank will still need new vis and or hydro but it will likely pass. Leave it empty... Might as well buy a new tank.

 

[Festus]

My tanks stay upstairs in the laundry room filled or at 500 psi . She who must be obeyed does not object. My garage has flammable crap and woodworking dust so not a great choice.

 

[redacted]

You know what's weaker than a burst disk?

The last few thousandths of an inch of aluminum and paint covering up a neck crack.

Especially when the tank hasn't been emptied or inspected in years.

There's a reason it's called "Sustained Load Cracking"

flots

I don't believe sustained load cracking is a recognized problem with modern aluminum materials. If they were my tanks and still full, I would drain them over a hour or so under water.

 

[Patoux01]

I'd store them at 50bar or something... Simply because I would dive them before storage.
Or without the valve and heads down, to make sure there's no water in it, but not sure that's the right thing to do.
I would avoid exposing them to really cold temperature, but what would cause issues is mainly temperature changes than just cold or warm imho.