Is it ok to store tanks outside in a shed

[awdemeo]

Hi all
I have 4 al 80 cf tanks currently i store them in my basement full but it is a pain to get them up and down every weekend to go diving. I live in the DC area and would like to store them outside in a patio box (plastic weather proof box) but was wondering if this was ok to do due to temperature changes around here. Thanks Alex

 

[Doc Harry]

Not an issue.

 

[Cylinder Tester]

I concur.

Roger

 

[I Dive]

I'd be more concerned about the box holding up in the elements than the tanks...

 

[Doc Harry]

I'd be more concerned about the box holding up in the elements than the tanks...

If you have valve covers, just keep about 300-500 PSI in the clyinders and throw a tarp over them.

 

[Wayward Son]

I'm thinking his concern is storing them in the shed, full.

Not a problem. I would use tape and/or valve covers (or DIN plugs if they're DIN) to make sure nothing gets in the openings.

 

[Leadking]

If they are 6351's store them at under 500 lbs. Remember SLC is Sustained Load Cracking!

 

[crlavoie]

OK... I'll be the guy to mix it up a bit. In my opinion, it depends. If you're planning to use them for winter diving, there are some folks that suggest that tanks should be stored inside and reasonable efforts made to keep them from freezing up to the time of diving. The reason is that any reg, sealed or not is capable of freezing and main reason is not so much cold ambient air or water, as it is the phenomonon of adiabatic cooling.

Adiabatic cooling occurs when a compressed gas expands as it moves from high pressure to low pressure. To see this in action, open a warm tank on an otherwise warm day and you will feel that the air is dramatically cooler than you would expect. The reverse of this is true when you are filling tanks and they become hot. With that in mind, my understanding of the theory is that you are starting the dive with an already cold gas that will become colder still as it moves from HP to LP and expands.

BTW, this guy does a far better job of explaining the concept:Cold Water Diving | Thinking Diver

Again, this is my interpretation of the theory and it should be approached with great caution and skepticism. Science aside, I've done it and have even attempted to purposely freeze a reg by free flowing it under water. Oddly enough, it mas my sealed Atomic B2 and 2 other SP MK25's that froze. My little unsealed AL Titan LX was just fine. Go figure.

 

[JanK]

From an article somewhere comes a recommendation to store them almost empty, so you should fill them just before a dive and their initial low temperature doesn't matter anyway. Otherwise the higher pressure (and thus pO2) accelerates any corrosion processes.

 

[Doc Harry]

From an article somewhere comes a recommendation to store them almost empty, so you should fill them just before a dive and their initial low temperature doesn't matter anyway. Otherwise the higher pressure (and thus pO2) accelerates any corrosion processes.

Actually, the OP wanted to know about storing them full. There is no problem with storing aluminum cylinders full for long periods of time. Even if the cylinders ended up not passing hydro later on, they're so cheap that you can throw them away and buy a new one.

Steel cylinders... now that's a different ball of wax. Some research performed back in the 1970s suggested that, with some moisture in the cylinders, the elevated cylinder pressure (that translates into increased partial pressure of oxygen, pO2) can accelerate corrosion of the steel. The number of cylinders in this old study was extremely small, and the conditions were rather extreme to shorten the study duration, but it's the only research that has even been done in this regard. This old study was the source of the recommendation to store steel cylinders almost empty to minimize the pO2.