Long term tank storage

[kjunheart]

I am sure this has been discussed but I couldn't find the info I wanted.

It looks as though I will not be diving again until sometime in 2004 ;-0 and I am not sure what to do with my new tanks (figures I have less than 5 dives on each). I store them in a closet in my apartment where it is cool. But do store with air or without? One tank is full and the other has about 700 psi. Do I let all the air out, most of the air or bleed over a period of time?

Any other suggestions you may have about storing my tanks and equipment for that length of time would be greatly appreciated!

Sandy

 

[WreckWriter]

Store them with about 500-1000 psi in them. Let the air out slowly to avoid creating condensation.

WW

 

[Padipro]

You don't have to do a thing. Just leave the tanks standing upright in a cool dry place with the air that is in them and they will be just fine the way they are. Of course the VIP (Visual Inspection Program) will have expired by then and they will need to be inspected before you can get them filled again but that's a good idea anyway if you've left tanks in storage for a length of time.

Scott

 

[joens]

a tank should be stored either full or nearly empty [100 psi]
not empty and preferably not in between one reason is that in the event of a fire a full tank will blow the burst disk with relatively little heat and one with 100 psi will not build up that much pressure .a tank with 1000psi -2000 psi will more than likely not burst the disc before the tank explodes .it only takes about 350 degrees to destroy the integrity of an aluminium tank. and before the tank gets that hot either the burst disk should have alreadyblown or not have enough pressure to create a hazard . the reason for keeping a little bit of pressure instead of completely empty is to keep miosture out .there has been some discussion about if storing the tank full for a long period of time causes unnecessary strain on the tank or not ,I wont get into that .If it was me I would leave the one full and drain the other down a little more .
Joens

 

[Cave Diver]

I would recommend storing them nearly empty.

You want to keep some air in them so that the tank pressure stays above ambient and keeps moisture etc. out.

The reason I say "nearly" empty, is because there are mixed opinions on the quality of air that has been stored for long periods of time. If you store the tanks full, you might be tempted to just go out and use them whenever you do your next dive, where as if you store them nearly empty you will be forced to get a fresh fill.

BTW, why no diving until 2004???

 

[FredT]

Fire safety indicates aluminum tanks should be stored full or empty (<500psi) but not in between.

Steel tanks can be stored either way, and anywhere in between, if the air in them is dry.

Either material: If stored full for over 6 months or a year simply sniff them for O2 content before using the canned air. Anything significantly lower than what you put in them indicates interior corrosion and a vip and gas change is in order before you use them. I have used air that has been canned for over 3 years with no problem, but check the O2 content first!

For long term storage depress the purge button on your second stage and bag it to keep the six and eight legged critters from moving in.

FT

 

[Walter]

Sandy,

I'll be glad to help ya, I'll let the air out of your full tank very slowly. What mix is in it?

 

[joens]

I will make a better offer I will keep the tanks for you and make sure they get used once in a while and when you are ready for them back just holler.
Joens

 

[Padipro]

FredT once bubbled...
Fire safety indicates aluminum tanks should be stored full or empty (<500psi) but not in between.
FT

Fred,

I can't say as I've ever heard that one about fire safty before. Could you elaborate a little on the subject?

Thanks,

Scott

 

[Walter]

Scott,

As you know, Amonton's Law explains pressure and temperature relationships. As heat is applied (as in a house fire) the pressure increases. If your AL tank is full the burst disk will blow releasing the pressure. If your AL tank has relatively high pressures (as Fred mentioned, more than 500 PSI, but not full) you run the risk of the tank failing before the pressure is high enough to cause the burst disk to blow. Heat weakens the walls of an AL tank and an explosion can occur. HTH.