expired VIP... air still good?

[geraldp]

Sorry for the dumb question (I did a search first).
My tertiary tank (al80) is 9 months past it's vip date. That puts the air in there about 15 -18 months old. Should I go ahead and dive with it and then get it vip'ed or have the vip done first?

Thanks,

Jerry

 

[brdr882]

personally, i'd get the VIP and with it the free fill. Something about breathing air that's over a year old doesn't appeal to me. I'm pretty sure there's a more scientific explanation but I don't want to make it up.

edit:

My tertiary tank

Thats quite the $.10 word!

 

[CAPNVINNY]

you can dive with it and get a new vip and fresh fill.There are many people that get to dive only a few times a year because of climate.He we routinely dont dive in the colder months so the last time we fill our tanks after the season till we go out again is usually 7 or 8 months.

 

[H2Andy]

there is nothing in air to "spoil" over time, so ... you'd be fine

 

[Scared Silly]

Actually there can be some thing to spoil. But not in this case because the cylinder is made from aluminum. There are some cases of the air in a steel cylinders being O2 depleted because of it being consumed during the rust formation process. Of course there needs to be a reason for the rust forming - like water in the cylinder.

That said, breath on it while on land for any odd tastes/smells. Otherwise go get a VIP and you will get a fill with it.

 

[H2Andy]

that's interesting

how long do you think it would take (assuming rusting) for the air to be made unsafe?

 

[jbd]

There was a discussion about this(O2 depletion) some years back. I don't recall the specifics.

 

[Scared Silly]

Ditto ... I can not remember all of the specifics either. I learned about this in my PSI Inspection course if my memeory serves me correct.

 

[spectrum]

that's interesting

how long do you think it would take (assuming rusting) for the air to be made unsafe?

I remember at least one clever chemist type posting about a year ago that the cylinder would essentially be a pile of rust and fail before the air was appreciably hypoxic.

This winter has been crap for diving, I'll be using a number of 5-6 month old fills soon, I hope!

Pete

 

[aowdan]

Sorry for the dumb question (I did a search first).
My tertiary tank (al80) is 9 months past it's vip date. That puts the air in there about 15 -18 months old. Should I go ahead and dive with it and then get it vip'ed or have the vip done first?

Thanks,

Jerry

not a dumb question whatsoever. aluminum tanks are self limiting for corrosion, meaning they only corrode "a little bit" and that's it. if it were steal, as stated before there is more chance of worse corrosion. just so you know, with alm tanks, most visuals are targeted towards the cylinder neck area. that is is the area were most problems with folds/cracks occur. send me the tank, i'll dive it.