Dangerous Goods List, Special Provisions and Packing Instructions
Reading the Dangerous Goods List
The Dangerous Goods List (DGL) is the master table. Each entry gives the UN number, proper shipping name, class or division, subsidiary risk, packing group, special provisions, packing instruction, quantity limits (passenger and cargo aircraft), and whether the item is forbidden, excepted or permitted only with approval. Candidates must be able to read across a row and apply every column, not just the class.
Special provisions
Special provisions are numbered codes that modify or add requirements. Some permit exceptions, some add conditions, and some prohibit carriage. A common trap is treating a special provision as optional; it is mandatory whenever it is referenced in the DGL row.
Packing instructions
Packing instructions are numbered (for example, 3xx series for Class 3 liquids) and specify the inner and outer packaging, maximum net quantities and whether single packaging is allowed. The packing instruction must match the substance, the packing group and the mode (passenger or cargo aircraft).
Worked example
A shipper wants to send a Class 3 liquid with packing group II by passenger aircraft. The DGL row lists packing instruction 353 and a passenger-aircraft quantity limit of 5 litres per package. The shipper's package contains 10 litres. The answer: the shipment cannot go by passenger aircraft under that packing instruction; it must be repacked to the limit or moved to cargo aircraft if the cargo limit allows.
Rule of thumb
Read the DGL as a checklist: UN number, name, class, packing group, special provisions, packing instruction, and both quantity limits. If any column fails, the shipment fails.