NBN EN 12257:2002

This European Standard specifies minimum requirements for the materials, design, construction, prototype testing and routine manufacturing inspections of composite gas cylinders with a water capacity up to and including 450 litres for compressed, liquefied and dissolved gases.
NOTE For the purposes of this standard, the word "cylinder" includes tubes up to 450 litres water capacity.
This standard is applicable to cylinders that comprise a seamless metal liner reinforced over a substantial part of the parallel length by wound composite fibres of glass, carbon, aramid, or wire.
This standard is not applicable to gas cylinders which are almost totally covered with fibres and commonly called "fully-wrapped" cylinders. For fully-wrapped composite cylinders see prEN 12245.
NOTE The specification does not address the design, fitting and performance of removable protective sleeves. Where these are fitted they should be considered separately.