This International Standard deals with seamless aluminium-alloy transportable gas cylinders intended for compressed and liquefied gases under pressure, of water capacity from 0,5 l to 150 l; it also applies, as far as practical, to cylinders of less than 0,5 l water capacity. This International Standard specifies the requirements for periodic inspection and testing to verify the integrity of such gas cylinders for further service. This International Standard does not apply to periodic inspection and testing of acetylene cylinders or composite cylinders with aluminium-alloy liners.