ISO 11623:2015 specifies the requirements for periodic inspection and testing and to verify the integrity for further service of hoop-wrapped and fully-wrapped composite transportable gas cylinders, with aluminium-alloy, steel or non-metallic liners or of linerless construction (Types 2, 3, 4, and 5), intended for compressed, liquefied or dissolved gases under pressure, of water capacity from 0,5 l up to 450 l. ISO 11623:2015 is written to address the periodic inspection and testing of composite cylinders constructed to ISO 11119‑1, ISO 11119‑2, and ISO 11119‑3 standards and can be applied to other composite cylinders designed to comparable standards when authorized by the competent authority. As far as practicable, this International Standard also can be applied to cylinders of less than 0,5 l water capacity.