Hazardous goods classification and hazard classes
What this domain tests
The RTO Hazardous Goods Test checks whether you can read a dangerous goods entry and assign the correct UN number, proper shipping name, hazard class, subsidiary risk and packing group. Classification drives every later decision: packaging, labels, placards, segregation and emergency response.
Core rules
- There are nine hazard classes: 1 explosives; 2 gases; 3 flammable liquids; 4 flammable solids, spontaneously combustible and water-reactive substances; 5 oxidizers and organic peroxides; 6 toxic and infectious substances; 7 radioactive material; 8 corrosives; 9 miscellaneous dangerous substances.
- A substance is classified by its primary hazard, not by its trade name. If it has more than one hazard, the primary class is shown first and subsidiary risks are shown separately.
- Packing groups apply mainly to classes 3, 4, 5, 6.1, 8 and 9: PG I = great danger, PG II = medium danger, PG III = minor danger. PG is not the same as hazard class.
- Use the dangerous goods list, safety data sheet and UN number to confirm the entry.
Worked example
A consignment is described as "motor spirit". The SDS gives UN 1203, flash point about -43 C, liquid, highly flammable. Reasoning: it is a liquid, gives off flammable vapour below 60 C, so Class 3; the UN entry is UN 1203 MOTOR SPIRIT or GASOLINE, Class 3, PG II. It is not Class 9 because its primary risk is flammability. The vehicle placard and paperwork must match that entry.
Traps
Using the product brand instead of the UN proper shipping name; swapping PG I and PG III; treating a subsidiary risk as the primary class; assuming all aerosols are non-hazardous.