What does "primary class" refer to in the context of TDG?

In the context of Transportation of Dangerous Goods (TDG), "primary class" refers to the main category under which a dangerous good is classified based on its primary hazard. This classification provides a systematic way to identify the inherent risks associated with transporting specific materials, which is crucial for ensuring safety during transport and handling.

Each dangerous good is associated with one primary class that corresponds to its most significant hazard (e.g., explosive, flammable, toxic). For example, a substance that is flammable will be classified primarily under the flammable liquids class, as this represents the greatest risk that it poses during transport. This classification plays a vital role in determining how the material should be packaged, labeled, and handled, in compliance with safety regulations.

Understanding the primary class of dangerous goods helps transporters and emergency responders quickly assess risks and take appropriate safety measures to manage those risks effectively.