ISO 11119-1 specifies requirements for composite gas cylinders up to and including 450 litres water capacity, for the storage and conveyance of compressed or liquefied gases with test pressures up to and including 650 bar. The cylinders are constructed in the form of a seamless metallic liner over-wrapped with carbon fibre or aramid fibre or glass fibre (or a mixture thereof) in a resin matrix, or steel wire, to provide circumferential reinforcement.

This part of ISO 11119 addresses cylinders with a design life from 10 a to non-limited life. For cylinders with a design life in excess of 15 a, and in order for these cylinders to remain in service beyond 15 a, re-qualification of these cylinders is recommended.

This part of ISO 11119 does not address the design, fitting and performance of removable protective sleeves. Where these are fitted they should be considered separately.