What is UN performance-oriented packaging and how does it relate to packing groups?

UN performance-oriented packaging is packaging that has been independently tested and certified to the structural and containment standards required for the packing group it is approved to carry. Drop tests are conducted from 1.8 metres for X-level (PG I) packaging, 1.2 metres for Y-level (PG II) packaging, and 0.8 metres for Z-level (PG III) packaging. Additional stacking, leakproofness, and hydraulic pressure tests apply depending on container type and contents. The results are marked on the approved container — for example, "UN 4G/Y" identifies a fibreboard box certified for PG II and PG III goods. A shipper must confirm that the letter code stamped on the packaging equals or exceeds the packing group of the substance being shipped before placing it in that container.