Are you using PI marked
valves and regulators ?

All Arrow Precision CO2 valves and compressed
air regulators conform to the new regulations ­and are marked, as are all cylinders supplied by Powerball.

From 30th of May 2002
“Pressure equipment and assemblies placed on the market and put into service in the United Kingdom and EEC must comply with the Pressure Equipment Directive (P.E.­­­­­­D)”
Source: DTI Product Standards Pressure Equipment URN 05/1074

Non maked valves cannot legally be used or supplied in the UK or EEC.

A fine of £5,000 and or imprisonment for up to 3 months can be imposed for breaking the regulations.

Use of non approved equipment, may invalidate your site liability insurance.

Refilling of non conforming equipment is a breach of regulations.

These laws are enforced in Great Britain by the
Health & Safety Executive.

Read the officall document :
Small gas cylinders and fittings for use in paintball sports