In the sequence for identifying components on a placard for flammable liquids, which part is labeled '1' for the United Nations hazard class number?

In the context of identifying components on a placard for flammable liquids, the part labeled '1' refers to the bottom number, which signifies the United Nations hazard class number. This number is a critical identifier used to categorize the hazardous materials based on their specific characteristics and the types of risks they pose. For flammable liquids, this classification helps emergency responders quickly identify the potential hazards associated with the substance in question, facilitating appropriate handling and response measures.

The bottom number serves as a universal reference, ensuring that firefighters, hazardous material teams, and other emergency personnel can effectively communicate the risks and manage incidents involving flammable liquids. Understanding the significance of this number is essential for ensuring safety and adherence to regulations in emergency situations.