Co2 expiry dates

dweb · Dec 14, 2023

My tank is nearly empty and I was checking my new spare tank which has been in my garage for about a year and noticed the expiry date on the sticker on the tap is June 2023. It's a 22.4kg tank. Is the co2 still ok?

jof · Dec 14, 2023

I very much doubt it will have 'gone off'

Leard · Dec 15, 2023

I've had tanks for over a year and they've been fine. It's literally just gas, not food. I'm sure the expiry date is down to some safety thing with the tank, rather than the gas not being suitable to use. Maybe each tank needs a yearly inspection or something?

Rodcx500z · Dec 15, 2023

To be honest i didn't know co2 has an expiry date

kenstel · Dec 15, 2023

Hmm, think the air we breathe has been around for a lot longer than a year. No indication its going off. Its just that mankind is polluting it. The world keeps recycling and regenerating it.

I know in scuba diving, there is concern that old air in a tank (the standard stuff is ordinary atmospheric air, filtered, not oxygen) can become tainted because any moisture in the air can cause corrosion in the tank which can cause noxious gases to be created. Scuba tanks have to be visually inspected internally every 2 years.

There may well be similar concerns about old CO2. The tanks themselves will be subject to inspection and pressure testing but I don't know precisely what. There may be labels or stamps in the neck of the bottle indicating test dates.

With scuba tanks, if it is out of test validity, no one will fill it because of the risk of 'bad things' happening. I can't believe other pressure tanks are different.

hoppyscotty · Dec 15, 2023

kenstel said:
Hmm, think the air we breathe has been around for a lot longer than a year. No indication its going off. Its just that mankind is polluting it. The world keeps recycling and regenerating it.

I know in scuba diving, there is concern that old air in a tank (the standard stuff is ordinary atmospheric air, filtered, not oxygen) can become tainted because any moisture in the air can cause corrosion in the tank which can cause noxious gases to be created. Scuba tanks have to be visually inspected internally every 2 years.

There may well be similar concerns about old CO2. The tanks themselves will be subject to inspection and pressure testing but I don't know precisely what. There may be labels or stamps in the neck of the bottle indicating test dates.

With scuba tanks, if it is out of test validity, no one will fill it because of the risk of 'bad things' happening. I can't believe other pressure tanks are different.

Well scuba tanks contain oxygen which is an extremely corrosive substance so there is an active reaction going on with compressed air inside a metal cylinder.

Not sure it's the same with CO2, but suspect it's there to ensure there is no degradation of the seals or the cylinder in some way rather than the gas 'going off'. Also co2 is usually in its liquid form in a co2 cylinder as you have a dip so under alot more pressure so again, more to worry about regarding the actual vessel it's contained within.

I suspect you'll be OK if you overshoot the 'best before date' as these things are always massively conservative anyway...we're talking factors of safety of 3 or 4.