Which statement correctly describes the relationship between the UN number and packaging instructions?

• A. The UN number is used to select the packing instruction.
• B. The UN number has no relation to packaging instructions.
• C. Packaging instructions determine the UN number.
• D. The UN number only indicates the destination.

Answer: (A)

The UN number identifies the material and drives which packing instruction applies. In dangerous goods transport, every UN number corresponds to a specific packing instruction that lays out how to package the item—what packaging types are allowed, how inner and outer packaging must be arranged, any fill limits, testing or leakage requirements, labeling, and other handling rules. Because this number comes from the substance itself, it is used to determine the correct packing instruction; packaging instructions do not determine the UN number. The UN number isn’t about destination—destination details belong to shipping documents and routing, while the packing instruction is dictated by the material’s hazard classification identified by the UN number. So, using the UN number to select the packing instruction is the correct relationship.