Hazard Classes and Divisions
What this domain covers
You must name the nine classes, know the divisions inside them, and read a shipping description to predict the hazard.
The nine classes
- Class 1 - Explosives, Divisions 1.1 (mass explosion hazard) through 1.6 (extremely low risk).
- Class 2 - Gases: 2.1 flammable, 2.2 nonflammable/non-toxic (oxygen, refrigerated liquids), 2.3 toxic.
- Class 3 - Flammable and combustible liquids: flash point at or below 60 °C (140 °F); combustible liquids run 60–93 °C.
- Class 4 - Flammable solids: 4.1 flammable solid, 4.2 spontaneously combustible, 4.3 dangerous when wet.
- Class 5 - Oxidizers (5.1) and organic peroxides (5.2).
- Class 6 - Toxic (6.1) and infectious substances (6.2).
- Class 7 - Radioactive: labels White-I, Yellow-II, Yellow-III; the category reflects the transport index.
- Class 8 - Corrosives: destroys skin or corrodes steel or aluminum.
- Class 9 - Miscellaneous: lithium batteries, dry ice, environmentally hazardous substances.
Packing groups
I is great danger, II medium, III minor. They are assigned to Classes 3, 4, 5.1, 6.1, 8, and some Class 9 materials - not to gases or Class 1.
Toxic-by-inhalation
Division 2.3 gases and Division 6.1 materials in Hazard Zone A or B are PIH: special placards, isolation distances, and route restrictions apply.
Worked example
A solid that ignites within five minutes of contact with air is not 4.1 - spontaneous ignition is the 4.2 definition. A material with a flash point of 38 °C is Class 3, PG III, because the flash point is at or above 23 °C but not over 60 °C.
Traps
Mixing up 4.1, 4.2, and 4.3; calling oxygen a flammable gas (it is 2.2); assuming all Class 9 materials are harmless; and assigning a packing group to a Division 2.1 gas.