Quote Originally Posted by angrybear View Post
In the rules for testing compressed gas pressure vessels.

As hareng above has put, there might even be a link in the stickies.
Which rules are they then?

Here's the rules. TPED.

http://www.conformance.co.uk/adirect...nsportpressure

Here's the UK law carrying out the EU directive

http://www.legislation.gov.uk/uksi/2.../contents/made

It makes reference to the directive, which in turn defines what is covered in section 2. There's some exceptions in section 6 from here.

http://eur-lex.europa.eu/legal-conte...X%3A32008L0068

So you'll have to do some cross referencing.

No where does it say under 500cc doesn't need a test. Well not that I can find.

What it says is that if it's manufactured to spec it should carry markings which should cover you for 10 years. Like Pi for instance (which is on at least one of my Walther tubes). This is why ISSF don't allow cylinders over 10 years in their competitions because presumably there's no way to remark thin walled cylinders even if they're tested, or perhaps because they're deemed to be industrial cylinders (pi) there isn't a established test method.

Industrial cylinders are covered by different tests to scuba cylinders designed to be used for breathing air... assuming they have the correct markings.