Scuba Tank Storage

[rstofer]

FWIW,

I have two Dacor, Super 80 tanks (Luxfer, I think) that were purchased new in 1991 (6061?). Both were filled and remained filled between dives every time I surfaced. I last dove one of them in 1995 and it's still showing 3000 PSI. The other, I couldn't tell you when I dove it last, but it's been longer than that. I'd like to put an analyzer on them to test the O2 percentage just for fun, but I don't have one.

My OW instructor used the basic function of metal fatigue as an example of why they should be stored full. And I always have. So far those are the only two tanks I've owned, and of course, haven't had problems with them, but they're both WAY past due for a hyrdo and viz.

I've been careful about moisture in them, but they've been stored full for over 13 years each; will they pass?

I have a pair of Luxfer tanks. One predates 6061 alloy and has been stored full for 20 years. The other is newer (1993) and stored full for 15 years. Both have passed hydro every 5 years and are due for testing in 2 years. I have no reason to believe the newer tank will fail. I have been told the cost to inspect the older tank has increased dramatically due to some change in the requirements for these older aluminum tanks. If so, I'll probably scrap it and buy a HP Steel 100. We'll see...

Both were VI'd and cleaned for Nitrox this year without concern.

An aluminum 80 is on the order of $140. That works out to about $7 per year - a little more than the cost of 1 refill at Monterey. So what if it only lasts 20 years?

Richard

 

[String]

The hot car/garage thing isnt likely to ever be a real life problem.

If you have a standard steel tank at its normal rated pressure of 232 bar in a room of 21c then in order to reach its test pressure (348 bar) the temperature would have to be raised to over 168c (334f).

No car, garage or house gets to anything like that temperature. Unless you shove it in a fire or jet exhaust that isnt a problem.

No idea about burst disks as ive never seen one and not even sure they're legal in europe but even with those im guessing you'd need some heating impossible to get just from the sun to cause it to bang.

Incidentally, if anyone wonders how much energy IS in a scuba tank, see here:

How much energy is there in a filled scuba tank

Answer:- About the same as 300g of TNT.

 

[Doc Harry]

I haven't forgotten abut y'all. I'm still waiting for more material to arrive via inter-library loan.

Looks like I'll have a lot of original research and data for you to consider. Some of you will be surprised by the information.

I'll post the data in a couple of weeks.

 

[Doc Harry]

There's been a bit of a snag.

The University of Rhode Island won't loan out some of the key research articles that I need.

So the next time I'm in Boston I'll drive down to Rhode Island to copy the articles.

So don't hold your breath waiting for my final paper.

 

[wlb03]

Man, you guys seem to be putting way to much into this....
As a firefighter, we have had our steel, al., and composite bottles in some of the most extreme conditions that you can get one into. As far as I know, over the years and countless bottles that we have and have had, only a very few have evently failed a hydro.
I do not foresee my scuba tanks suddenly failing anytime soon...

 

[Doc Harry]

Scuba cylinder long term storage: fact and fiction

 

[divepirate]

save our savers!
keep 'em full.
when your house/garage burns, the burst disc will go first, saving the brave firefighter from wearing your scuba tank as a mask.
as already mentioned, it is the filling/depleting cycle that causes fatigue, so full or near empty, wont affect the tank...
good question though, thanks.