Tank storage and life span

[TwoBitTxn]

I keep my aluminum tanks inside the house where they aren't exposed to drastic temp changes. No highs of the summer around 100 or lows of the winter around 15*F. Does it matter if I store them full or should I keep them with around 500 lbs of air in them? I know not to store them empty.

Second question: What is the average lifespan of an aluminum tank. I'm sure the variables of salt or fresh and frequency and number of fills and proper care all have factors but about how long should a talk last before it fails hydro or the neck cracks?

Tom

 

[Thomas Ivey]

Originally posted by Tom Vyles
I keep my aluminum tanks inside the house where they aren't exposed to drastic temp changes. No highs of the summer around 100 or lows of the winter around 15*F. Does it matter if I store them full or should I keep them with around 500 lbs of air in them? I know not to store them empty.

Second question: What is the average lifespan of an aluminum tank. I'm sure the variables of salt or fresh and frequency and number of fills and proper care all have factors but about how long should a talk last before it fails hydro or the neck cracks?

Tom

Recommended storage of any scuba cylinder, is if you do not have immediate plans on diving there is no logical reason to keep a fully charge cylinder in your house, garage or car. Best is to keep a minimum of 50 psi in the tank. If at the end of your dive season (if you have one) it is a good idea to have the tank internally visual, so there is no possibility of having any standing water in it. The tempatures stated will not have any effect on your scuba cylinder.

Life expediency for scuba tank is roughly 25 years. Actual life will be based on the life the tank experiences. This why we hydro scuba cylinders every five years and have a visual done at least once a year. The new Eddy current equipment that is know in the market place seems to be keeping the cracked neck issue (sustained load cracking) SLC, in check. I think the last published finding from Luxfer Gas Cylinders is to have this done every two years. Steel tanks are not involved with SLC, this seems only to be aluminum tank issue. If you talk to a retester they will tell you that more tanks are removed from service due to excessive use than failing the hydro test.

ti

 

[scuba_guy]

if your storing your tanks for any period of time. drain the tank down to around 200psi if you keep it topped up , it stresses the tank. also over a period of time it will start to develop a lower O2 content.as the O2 starts to oxidize the tank

 

[Thomas Ivey]

Originally posted by scuba_guy
if your storing your tanks for any period of time. drain the tank down to around 200psi if you keep it topped up , it stresses the tank. also over a period of time it will start to develop a lower O2 content.as the O2 starts to oxidize the tank

I have never heard of this before, where can I get further detailed information regarding what you have stated.

ti

 

[scuba_guy]

it was in the PSI course i took, with AAL tanks in time the O2 content will deplete its self as oxidization occurs. it does take a long time but thats what happens

 

[Thomas Ivey]

Originally posted by scuba_guy
it was in the PSI course i took, with AAL tanks in time the O2 content will deplete its self as oxidization occurs. it does take a long time but thats what happens

Thanks for the info, it was my uderstanding that when the O2 level is depleted the corrison would stop, since there is no oxidating agent present. The time element would it be relevent to a scuba divers that stores his tank in the off season?

ti