Maybe someone from Europe can help out with the Carbon fiber tank rules.

To the best of my knowledge carbon fibre tanks require testing every 5 years (here in UK), Mike.

They have an overall life of 15 years (so, 3 tests) - they are not used by Divers of course - maybe their lightweight construction is the reason for that lifespan. Most Dive shops are just as 'interested' in the tanks' valve gear as the tank wall condition (when testing).

That is my understanding of the UK situation.

It all depends on what bottle it is.
For instance, I have a ABB interspiro 7 Liter CF bottle which is "NLL" (non limited lifetime).
It needs a visual inspection and hydro test every 5 years. As long as it keeps on passing the hydro test, it is OK. There is no expiring date on this bottle.

I also have a 6 Liter Dräger (luxfer) bottle with a 20 year design life. This one also needs a hydro test every 5 years until the end of life date is reached.
However, in NL some hydro stations can proof it as being a industrial bottle if desired, then it needs a hydro test every 10 years. It can't be used for diving anymore in that case.
But to be sure, please check your local regulations, different countries, different regulations

kind regards,

Gijs 

Interesting. I think in the US, the main users of carbon fiber wrapped tanks are firemen. Just like divers, their life depends on the function of that tank.

We need to get a new category on the books for airgun fill tanks. Our life doesn't depend on it, we just need them not to explode or leak. I see "expired" CF tanks for sale often, but they're only useful to those of us with compressors. I say "us" but I'm not one of those blessed few, hehehe.

I've heard 2 reasons why Divers DONT USE these CF tanks:

1) Obvious really they're too light !!! ie: much too buoyant to be of use

2) Sea water / salt water was stated as "unsuitable" for Carbon Fibre

This was stated to me by a regular Diver I know.