Winter storage for SCUBA tanks

[SDAnderson]

It's November in Chicago. That means the season is pretty well done for unless you have anti-freeze for blood. Time to pack up the gear for the next several months. I have some questions about storing SCUBA tanks and am looking for advice.

The tanks: Luxfer AL80's - I looked at Luxfer's website and couldn't find any information, so here goes:

How cold can they get? Is there a preferred ambient temperature? Does it matter if the ambient temp fluctuates between, say, 20F and 70F?

How much of a charge should be in the tanks? Is 500 psi better than 3000 psi? Somewhere in between?

Anything else I should know about overwinter storage but am too ignorant to ask?

Thank you in advance.

 

[Ontario Diver]

Hey-o reefraff;

Just did my equipment course up here in Toronto - (My LDS takes it real serious - lot of extra stuff beyond the PADI requirements)

We covered storage of tanks and other gear....

Now speaking from the PADI Equipment Specialist Pulpit

Tanks should stored upright and with 300-500 psi.

I don't believe that the air temp is a major issue as long as it doesn't fluctuate too much, which would cause internal condensation, which leads to rust. (Extemes, of course; could harm o-rings and stuff but I don't think that that is an issue in this case....)

Basement (off the floor - floors get cold through conduction whch causes condesation, yada yada yada.) or closet should be ok. Of course since they are upright, they need to be secured......

Any other opinions?

 

[MrMrEZG]

according to TDI's visual tank inspection course. A tank should be stored either full or with less than 300psi. the reason is that if in a fire a full tank's burst disc will rupture before the tank heats up enough to fail catastrophicly.

with less than 300psi the tank will soften enough, to fail
non-catastrophicly, prior to the pressure rising high enough to cause failure. anything in between could be bad.

I probably have not explained this as well as it should be explained so if you have any questoins just ask.

 

[SDAnderson]

Thanks - two great responses. I appreciate the input. Tough enough to keep all of the gear in shape through the regular season without letting it get trashed from inactivity.

Toronto, eh? I sacrified a bunch of weekends at a little mudhole not too far from you called Tobermory, although it's been awhile. I have REALLY great memories of diving Fathom Five MP, hopefully the park is still being well taken care of. Love to get back someday.

Again, thanks to both for the advice.

 

[The Chairman]

Tanks should now be EMPTIED when not in use. It will eliminate the sustained load cracking (room temperature grain creep) and even a tank with 300 can rupture catastrophically in a fire. Yes, this goes against all that we were previously taught, but it is the current deal... I just took my PSI tank inspection course yesterday and this was one of the "hot" topics.

 

[blacknet]

Ontario Diver,

Why upright?

Ed

 

[The Chairman]

1) If there is any liquid, it will concentrate in the base instead of being spread out along the wall. This will localize corrosion to one ring near the base, instead of two longer lines along the side.

2) Circumferential distortion is avoided. One tank manufacturer recommends that their tanks be taken to %90 of their hydrostatic test range for 1 minute then released before the actual hydrostatic test is performed. They claim this will round the tank out.

 

[syruss32]

Originally posted by NetDoc
Tanks should now be EMPTIED when not in use. It will eliminate the sustained load cracking (room temperature grain creep) and even a tank with 300 can rupture catastrophically in a fire. Yes, this goes against all that we were previously taught, but it is the current deal... I just took my PSI tank inspection course yesterday and this was one of the "hot" topics.

Where did this info come from NetDoc? Won't the tank have to be inspected again before use if you do this? Sounds like Padi Propoganda to get more money into the LDSs again hehehehe

 

[The Chairman]

We read their memo in class on Sunday...

 

[Ontario Diver]

Originally posted by blacknet
Ontario Diver,

Why upright?

Ed

NetDoc is right about the reasons to store upright. Make sure that they are secured.

All you need to keep the tank dry is 50-300 psi to have some positive presure. If it is completely emptied, it is expected to be VIS'ed. You need a really hot fire to blow the tank (the burst disk will go first. )

Pete - it that memo on thier web site?

Matt