Classification of dangerous goods
Domain 3 - Classification. The exam tests whether you can assign the correct class or division, subsidiary risk, packing group and proper shipping name from given properties or test data.
The nine classes
- Class 1 explosives (divisions 1.1–1.6), Class 2 gases (2.1 flammable, 2.2 non-flammable non-toxic, 2.3 toxic), Class 3 flammable liquids, Class 4 (4.1 flammable solids, 4.2 spontaneously combustible, 4.3 dangerous when wet), Class 5 (5.1 oxidizers, 5.2 organic peroxides), Class 6 (6.1 toxic, 6.2 infectious), Class 7 radioactive, Class 8 corrosives, Class 9 miscellaneous.
- Packing groups I, II and III express degree of danger and are not assigned to Classes 1, 2, 6.2 or 7.
- Where several hazards exist, the precedence-of-hazard table decides the primary class; the other hazards become subsidiary risks and drive subsidiary labels.
Worked example
A liquid has a closed-cup flash point of 12 °C and an initial boiling point of 40 °C. It is a Class 3 flammable liquid. Because the initial boiling point is above 35 °C and the flash point is below 23 °C, it falls in Packing Group II, not PG I. If oral toxicity data also met the Class 6.1 criteria, the precedence table would decide whether Class 3 or 6.1 becomes primary, and a subsidiary label would be added.
Traps that cost marks
- Assigning PG I whenever the flash point is low, without checking the boiling point criterion.
- Using the lowest flash point from any source rather than validated test data.
- Forgetting to record a subsidiary risk, then omitting the label and the declaration detail.
- Treating Class 9 as unrestricted; lithium batteries, dry ice and magnetized material are Class 9 entries with real conditions.
- Using a trade name as the proper shipping name instead of the DGL entry, for example choosing a brand name where a n.o.s. entry with a technical name is required.