Packing, Marking and Labelling
Packing
Packing must be UN specification packaging where required, and the packaging must be marked with the UN specification code. The code tells you the packaging type, the packing group it is approved for, and the maximum gross mass. Inner packagings must be secured against movement, and absorbent material is required for liquids in certain cases. A common trap is using UN specification packaging that is approved for packing group III for a packing group II substance; the code must match or exceed the required packing group.
Marking
Marking includes the UN number and proper shipping name, the shipper's and consignee's names and addresses, and the UN specification mark on the packaging. Markings must be durable and legible.
Labelling
Labels show the hazard class. Primary hazard labels go on the package, and subsidiary risk labels are added where required. The "Cargo Aircraft Only" label is used when the shipment is forbidden on passenger aircraft. Orientation labels (the "package orientation" arrows) are required for certain liquid packages.
Worked example
A package is marked with a UN specification code ending in "X" and carries a Class 3 label. The shipper wants to add a Class 8 subsidiary label. The X in the code means the packaging is approved for packing groups I, II and III, so it is acceptable. The subsidiary label must be applied adjacent to the primary label, not replacing it. The answer: the package is acceptable once the subsidiary label is added correctly.
Rule of thumb
Match the UN specification code to the packing group, then check that every required mark and label is present, durable and correctly placed.