Storing tanks under pressure, how long?

[UnderSeaBumbleBee]

Did you use the seach function of this site before posting, because there are a BUNCH of threads on this subject.

You know if everyone used the search function every time the had a question, as long as this board has been around the conversation and interaction would stop. Scuba isn't developing rocket science and a planned trip to Mars. Since this board has been around for so long, just about everything has been covered.

Can you name any topic, dive location or other matter that hasn't been discussed several times that you would permit us to discuss?

I wonder why it upsets you that someone asked a question on a public discussion board, and that people responded to help the person with their question? And what is it about you that doesn't want to allow other people to express themselves and interact with others?

By the way, I have been reading the thread from the start. I often lurk on thread topics that I think I would learn something from when I click on new posts and notice a thread that I find interesting. Not knowing everything I don't know, it is hard to do a search on that. I have learned useful information from the above posters.

There are 6 conversation participants and several others reading the discussion. Seriously, who are you to waltz into a conversation to tell everyone to stop and not do it again but rather do a search first? And before you say you never said that, it is exactly what you said/implied when you scolded the OP for not doing a search first and stating that there were already a bunch threads on the matter.

 

[M_Bipartitus]

As long as the storage temperature does not go below the dew point of the air in the tank it will be fine. I wouldn't store them in unheated spaces in winter temperatures.

Most air should be dry enough that dew isn't that much a problem. The concern over rust is that elevated partial pressures of oxygen will increase the speed of rusting and the extent to which rusting can occur. This is related to Le Chatelier principle and the models for reaction rates. It shouldn't be important unless you have very high FO2 in your stored cylinders and enough moisture so that there is actual drops of water in the tank. Rust can occur without drops, but liquid water catalyzes the "rusting reaction" speeding it up substantially. Salts in the water speed the reaction up even more. ( This doesn't address the mechanical stresses discussed elsewhere)

Basically, a well maintained tank filled by a well maintained compressor should have no problem.

 

[TulsaVet64]

good info, thanks.

 

[diver 85]

Forever

and ever------now, how bout dem Tigers.....

 

[DA Aquamaster]

The concern over rust is that elevated partial pressures of oxygen will increase the speed of rusting and the extent to which rusting can occur. This is related to Le Chatelier principle and the models for reaction rates. It shouldn't be important unless you have very high FO2 in your stored cylinders and enough moisture so that there is actual drops of water in the tank. Rust can occur without drops, but liquid water catalyzes the "rusting reaction" speeding it up substantially. Salts in the water speed the reaction up even more. ( This doesn't address the mechanical stresses discussed elsewhere)

Basically, a well maintained tank filled by a well maintained compressor should have no problem.

The critical issue here is moisture. I store my steel 45 deco bottles full with 80% to 100% O2 in them and they are consistently free of even flash rust from year to year.If the gas is suitably dry going in, rust is not going to be an issue regardless of FO2 or PO2.