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Transportation of Dangerous Goods study materials
Transportation of Dangerous Goods study resources

Transportation of Dangerous Goods: Classification of Dangerous Goods

Transportation of Dangerous Goods · Work through your exam, one topic at a time.

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Classification of Dangerous Goods

Classification of dangerous goods

This domain tests whether you can assign class, UN number, packing group, and proper shipping name from properties and transport conditions. Questions often use flash point, boiling point, toxicity, corrosivity, or a mixture with several hazards.

The nine classes

1 Explosives; 2 Gases; 3 Flammable liquids; 4 Flammable solids, spontaneously combustible, dangerous when wet; 5 Oxidizers and organic peroxides; 6 Toxic and infectious substances; 7 Radioactive; 8 Corrosives; 9 Miscellaneous. Class determines label, packaging, segregation, and documentation.

Precedence and packing groups

  • Classify by the hazard the goods present in transport, not by intended use or trade name.
  • Use test data, SDS, and the regulations' decision logic. If several hazards apply, apply the precedence rules and assign subsidiary hazards.
  • Packing group reflects degree of danger: I great danger, II medium, III minor. Not every class has packing groups.
  • For Class 3, a liquid with flash point at or below 60°C is flammable. PG I if initial boiling point is at or below 35°C; PG II if flash point is below 23°C and boiling point is above 35°C; PG III if flash point is 23–60°C and boiling point is above 35°C.

Worked example

A solvent has a closed-cup flash point of 38°C and initial boiling point of 120°C. It is Class 3 because the flash point is at or below 60°C. The boiling point is above 35°C, so PG I does not apply. The flash point is not below 23°C, so PG II does not apply. It is PG III. The proper shipping name must match the entry; solvent alone is not enough unless it is the listed name.

Traps

  • Classifying from flash point alone and ignoring boiling point.
  • Assigning PG I because the liquid is volatile; volatility is not the PG test.
  • Missing a subsidiary hazard, such as a toxic or corrosive property.
  • Using an SDS section 2 heading without checking transport-specific data.
  • Forgetting that mixtures and solutions may have their own UN entries.

Exam focus

State the class first, then the UN number and proper shipping name, then PG. Show the deciding property in one sentence.