（Please give us guidance on how to package cylinders.）
30 small cylinders each containing 500mL of Div. 2.2 UN 3159 Refrigerant gas R134a is to be shipped. As stated in PI 200, cylinders with capacities of 1L or less must be packed in outer packaging constructed of suitable material and of adequate strength and design in relation to the packaging capacity and its intended use, a strong fibreboard box is used as outer packaging. Should we consider the 30 small cylinders as inner packaging and the fibreboard box as outer packaging, or should the 30 small cylinders be considered as outer packagings and the fibreboard box as an Overpack? Please advise. (31 Jul 13)
To start out with, the 30 small cylinders would have to be UN certified cylinders satisfying the requirements of DGR 6.4. If not, they should be non-UN cylinders however certified according to the laws of the country where they are produced according to DGR 6.4.3.
Consequently all the 30 small cylinders are considered as “outer packagings” and the strong fibreboard box that contain these 30 small cylinders is an Overpack.