How long is it safe to store air in your scuba tanks?

[Bogie]

How long is it safe to store air in your scuba tanks safely without resupplying with fresh air?

I personally would not use air that was over 60 days. (just my preference)

How does Oxygen content degrade in stored scuba tanks? You start with an air fill with the normal 21% Oxygen. If you store a full tank for 3,6, or 12 months does the Oxygen content decrease? What if stored longer 2, 3, 5 years? Does temperature, moisture, or other factors contribute? What about type and physical make up (steel, AL, composite) of the tank? Are there other factors (rust, organic growth etc.) that can make the air unsafe?

Do the other gases of air in the tank change concentration? (Nitrogen, carbon dioxide, argon)

Are there any scientific studies on this?

[wedivebc]

There was a thread like this year ago and the upshot was the tank would weaken and probably explode before corrosion had consumed enough oxygen to become hypoxic. I would say there is not practical shelf life on a

[DevonDiver]

When you get a fill, be sure to confirm what the 'best before' date is. This can vary from store to store, depending on what air they use to fill. I prefer organic air, without artificial preservatives - my body is a temple. The downshot is that organic doesn't last as long in storage.

You can also improve shelf-life by refrigerating your air. It's amazing how many people overlook this. If the air is going to be in storage for a very long time, for instance beyond 2 months, then you can always freeze it. However, once thawed, don't refreeze it again. If you like to plan your diving a long way in advance, just get frozen air from your LDS.

I don't see much point to buying the expensive 'imported air' that some people claim is much nicer. Gas imported from the Himalayas, Artic or Amazon regions has a ridiculous price tag, but if stored for longer than a few weeks will just lose all its flavour.

Locally produced 'free range' air is more than sufficient, unless you're rich. Farm produced is an adequate compromise. I do avoid mass-produced factory air though, as it's not so healthy. Just look for the 'free range' sticker at your LDS and you'll be fine.


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:D




Also these threads are helpful:

http://www.scubaboard.com/forums/basic-scuba-discussions/254495-scuba-tank-storage.html

http://www.scubaboard.com/forums/general-scuba-equipment-discussions/353426-bleed-old-air-tank.html

http://www.scubaboard.com/forums/tanks-valves-bands/404384-how-long-can-air-sit-tank-2.html

http://www.scubaboard.com/forums/tanks-valves-bands/2090-tank-storage-life-span.html

[Searcaigh]

Would not want farm fresh air really, it stinks of poo as any good farmer will tell you :D

[LowDrag]

Hey Devon,

Not that I am questioning you or anything but are you kidding about "organic air" or what??? :confused: I know I am new but my gullible meter is screaming at me...LOL!!! Do I need to recalibrate it or is this an early Aprils Fools joke? :D

[DevonDiver]

Yes, it was a joke. You killed the vibe now... shame on you ;)

The links I posted are valuable though. I just couldn't be bothered to copy and paste my previous answers on the same subject. It was far more fun to create some bad photoshop :)

However, given some of the junk ideas promulgated by the scuba industry to make cash out of diver enthusiasm/naivety... I'm surprised that nobody came up with the idea seriously yet. LOL It's not much dafter than a 'nitrox' Spare Air. :)

[Jim Lapenta]

Andy is not kidding. I only use organic air from reliable sources. So that means no air fills from NY, LA, Chicago, or the shop that takes in their air in DC from the Capitol building. I also do not store air in tanks longer than 6 months unless it is the air specifically desginated for use after the apocalypse this year. Unless you have bugs or mold growing in tanks storing air for up to 6 months is no big deal. If they need to sit longer than that why do you even own tanks?

[LowDrag]

Yes, it was a joke. You killed the vibe now... shame on you ;)


Oh CRAP!!! I guess my gullible meter was dead on and I should have realized that and played along...:dork2:


Sorry man!!!

[reo]

I remember someone in Florida a few years back was selling bottled hurricane air--air bottled during a hurricane.

Ron

[reo]

Andy is not kidding. I only use organic air from reliable sources. So that means no air fills from NY, LA, Chicago, or the shop that takes in their air in DC from the Capitol building. I also do not store air in tanks longer than 6 months unless it is the air specifically desginated for use after the apocalypse this year. Unless you have bugs or mold growing in tanks storing air for up to 6 months is no big deal. If they need to sit longer than that why do you even own tanks?

I would use the Capitol Building air in a separate tank for my drysuit inflation gas. Cheaper than Argon, and a plentiful supply.

Ron

[DevonDiver]

I remember someone in Florida a few years back was selling bottled hurricane air--air bottled during a hurricane.


That makes sense. Hurricane = high pressure area. More pressure = more air in the tank = longer dives. :)

Normally atmospheric pressure isn't an issue, because most bottling occurs at sea level. Inland dive centres may be at a higher altitude (less air pressure) - and consequently give weaker fills. I'd always get my fills from a sea-level cannery.

I heard that they get helium from mines... higher pressure then, as below sea level.... better for deep diving. That's a primary benefit.

They should mine for regular air too... for those of us who like deep air diving. It'd also make Nitrox production cheaper. Less oxygen at altitude. More oxygen at depth. Would save having to blend, if they took nitrox directly from a deep well. I'm sure someone could calculate what depth needed to be bored to obtain 32%.

[Wolfie]

I like the Jamaican deep air blend myself!

[DandyDon]

That makes sense. Hurricane = high pressure area.
Ding ding ding...!!

A tropical cyclone is a storm system (http://en.wikipedia.org/wiki/Storm) characterized by a low-pressure (http://en.wikipedia.org/wiki/Low_pressure_system) center and numerous thunderstorms (http://en.wikipedia.org/wiki/Thunderstorms) that produce strong winds and heavy rain
I keep a tank filled at my house and it often goes a year or more between fills. Still dive it.

[nolatom]

No "mile-high" air from Denver either....I want sea-level air.

[Searcaigh]

Theoretically then, air filled at the level of the Dead Sea would be better still.

[ajtoady]

I find there's nothing like "winter air", cool, crisp and clear! My tanks are rotated just about every week so as not to go stale. It just makes sense to go diving each and every weekend and burn two tanks of air. I have three tanks and I have yet to have one full for more than 5 weeks. Why take a chance on wasting a fill?:D

[Wolfie]

FWIW - I understand that Dandy Don checks his CO and O2 before every dive. Therefore IF something is happening inside his tank with moisture or what not he would know. This seems like a great idea even though the equipment is not cheap...

[WreckDiver1321]

Remember, ALWAYS roll your tanks down the driveway before every dive trip. That will ensure the gas re-mixes properly just in case it had separated. :D
Driving down a bumpy gravel road with the tanks unsecured in the back of the vehicle will work too.

Damn! I live in Montana, so I can't get at any of that high pressure sea level air! I have to live with the short fills given from high altitude.
Maybe I could convince my LDS owner to invest in one of those wells....

:popcorn:

[Tracy Saunders]

Andy is not kidding. I only use organic air from reliable sources. So that means no air fills from NY, LA, Chicago, or the shop that takes in their air in DC from the Capitol building. I also do not store air in tanks longer than 6 months unless it is the air specifically desginated for use after the apocalypse this year. Unless you have bugs or mold growing in tanks storing air for up to 6 months is no big deal. If they need to sit longer than that why do you even own tanks?

I thought the Air from Washington DC was the same quality as the one from the Dairy Farm.... :D:rofl3: Especially the ones from the White House. :D

[eponym]

Some great advice so far.

I'm currently bidding on some very rare air, tanks filled in Jan 1952 in England. These could be the last air from the reign of King George the sixth.
The tanks will be out of hydro, of course, but still . . .

-Bryan

[meebs86]

I remember someone in Florida a few years back was selling bottled hurricane air--air bottled during a hurricane.

Ron

Better watch out when you unleash that.. that's some high powered air right there! /s

[beaverdivers]

There's nothing better than Rocky Mountain Fresh Air mixed w/ PURE O2!

[KWS]

HEY BOGIE.

Good question. My opinion;;;;;; you dont leave tanks on full presure for storage. metel has to relax sometine. There is somewhere a thing about storing less than 50 lbs psi. that is not for protecting the the material from presure. i has to do with corrosion. steel rusts in o2 environment the higher psi the higher the ppo2 and the faster the rusting process. So i think that is the real reason for storing at lp and not working psi. most willl not see anything in the tank as most fills are good dry air, however a damp fill could do you in over time. i have not seen problems in my tanks having them full for a year and the o2 is good when i test them prior to use but i now make it a practice to run them down to <100 for the rusting issue. one never knows what he got filled with the last time. besides who needs a "BOMB" in the closet. Especially if your dive site has a good filling service.

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How long is it safe to store air in your scuba tanks?
How long is it safe to store air in your scuba tanks safely without resupplying with fresh air?

I personally would not use air that was over 60 days. (just my preference)

How does Oxygen content degrade in stored scuba tanks? You start with an air fill with the normal 21% Oxygen. If you store a full tank for 3,6, or 12 months does the Oxygen content decrease? What if stored longer 2, 3, 5 years? Does temperature, moisture, or other factors contribute? What about type and physical make up (steel, AL, composite) of the tank? Are there other factors (rust, organic growth etc.) that can make the air unsafe?

Do the other gases of air in the tank change concentration? (Nitrogen, carbon dioxide, argon)

Are there any scientific studies on this?







dioxide, argon)

Are there any scientific studies on this?[/QUOTE]

[randy88k5]

This should answer most of the questions

http://www.scubaboard.com/forums/tanks-valves-bands/260189-scuba-cylinder-long-term-storage-fact-fiction.html

[cbrich]

I like to add a little Scope to my air, so it's Minty Fresh. :rofl3::rofl3::rofl3::rofl3::rofl3::rofl3:

[Garth]

Until the next hydro/viz?

I don't feel it's safe to let air sit for two weeks and that's why I tell my wife I have to dive at least once a week.

[Hatul]

Along the lines of Andy's post, being into animal welfare I only buy cage free and free-range air. Sure it costs a little more, but I feel better that the animals are treated humanely.