This document specifies minimum requirements for the materials, design, construction, prototype testing and routine manufacturing inspections of composite gas cylinders and tubes for compressed hydrogen. NOTE 1 Unless specified in the text, for the purposes of this document, the word cylinder includes tubes. This document applies to: fully wrapped composite cylinders (Type 3 and Type 4); hoop wrapped cylinders (Type 2); with carbon fibres intended to be permanently mounted in a frame (e.g. bundle or trailer) with a test pressure of not less than 300 bar, with: non-metallic liners (Type 4) or seamless metallic liners (for Type 2 and Type 3); a maximum water capacity of 3 000 l; a maximum working pressure of 1 000 bar; the product of working pressure times water capacity (p × V) not exceeding 1 000 000 bar.l. NOTE 2 A glass fibre protective layer is sometimes applied to the external surface of the cylinder.