Full Tank Storage - How Long is Too Long?

[rustyshakelford]

i just had two tanks hydro'd that i had forgotten about in storage and sat for about 9 years. they both had air and were above atleast 2000 best i can remember. I drained them and dropped them off and there were no reported ill effects noted.

they were also al80s

brett

 

[DA Aquamaster]

I guess next time I rent a tank, I'll flip it over and see if it has a "Best If Use By" date on the bottom.

For freshest air, breathe by 1 December 2009

Its already got a "BORN ON" date - you will always know for a fact that the gas in the tank was put there after the initial hydro test and in most cases since the last hydro test.

 

[LeadTurn_SD]

i just had two tanks hydro'd that i had forgotten about in storage and sat for about 9 years. they both had air and were above atleast 2000 best i can remember. I drained them and dropped them off and there were no reported ill effects noted.

they were also al80s

brett

When I returned to diving in 2007, I rumaged through my old gear, and found my original steel 72, hydro 1976. The last time I had used it was in 1982. I had stored it with with about 500 lbs of air all those years.... I was afraid of what it might look like inside, but took it down to the dive shop, had it inspected.... some very mild rust that tumbling took care of, it passed hydo and "+" rating without a problem. It did blow the blow-out plug when we tried to fill it after hydro (we figured it probably would, but tried for fun...). Put in a new blow-out plug, and it's been diving happlily agains since.

I'll be diving it again this weekend, weather permitting

Best wishes.

 

[mark00020]

Static hoop stress so far under yield strength with have no negative effects (except marginal creep over a VERY long period of time, which the alloys that cylinders are made from are designed to minimize.) Keep in mind that while your tank has a working pressure of XXXX PSI, it is designed with margin of safety to keep it from failing under dynamic loading (quickly filling, or even more so hydro test that pumps it to 5/3 working pressure) so in all honesty, 3000 or 3500 PSI static load isn't going to stress the tank.

 

[Doc Harry]

The search function will produce many answers.

Last year I posted a long article reviewing all known data regarding long-term storage of scuba cylinders.

Try here