Have a read of the ukpsf hpa1 air safety information:
http://www.ukpsf.com/index.php/paintball-players/high-pressure-air-safety-guide/
Specifics may vary by the actual type / standard of cylinder and legislation over time, but currently you would expect the following:
Fibre cylinder:
15 year maximum lifetime with 5 years between tests
Ultra lite fibre cylinders previously were disposable and could only be used for 5 years. This is no longer true for current designs and you should be able to expect 15 years maximum with 5 year tests, but there may be cylinder designs in use with a different schedule.
Steel (you're unlikely to find one)
Unlimited maximum lifetime with 5 years between tests
Aluminium
Unlimited maximum lifetime with 5 years between tests. In fact legislation allows for 10 years but not all sites will recognise this, some will
Compact aluminium
Unlimited maximum lifetime and exempt from tests
With all cylinders check the label
When you buy new unless you are lucky and pick up the cylinder the day it arrives in the shop, straight from the factory you won't get a new born cylinder
It will have been manufactured, shipped around, stocked in warehouses etc. so it will be normal to lose a few months
Everytime you use it you are responsible for checking it's condition, the same as driving a car, the driver is responbsible for the tyres, wipers etc
If there's anything visually wrong with a fibre such as a scratch then don't fill it. Have it looked at
If there's a scratch on an aluminium then happily ignore it, it's only paint. But you're still responsible, if it's something that could affect integrity then don't use it
If in doubt a 'competent person' can look it over for condition
Testing can happen at anytime, you don't have to wait for the 5 year mark.
Testing starts with a visual, and can fail on this. If the fibre wrap is gouged then testers won't bother continuing and will fail it
The next stage is overpressurising in water and checking the expansion. The cylinders markings specify the test standards, if it explodes or expands out of the tolerance it fails
If it's within specifications it passes
The cylinder gets a new label and you get a matching certificate
Secondhand aluminium sales are rare, you can happily buy new for little £
Equaly people don't tend to retest them as they are cheap enough to replace
Fibre wraps typically go for about £80 for various ages
If you assess a fibre at £150 new, plus 2 tests across its life, eg £25 per test (prices vary) then it has a life cost of about £200
Divide £200 by 15, multiply by the number of years left and deduct £25 for any future tests
That gives you its 'value'
