Class 3 - Definitions

Flash point is defined as the lowest temperature at which flammable vapor is given off a liquid in a test vessel in a sufficient concentration to be ignited in air when exposed momentarily to a source of ignition. The flash point of flammable and combustible liquids may be altered by the presence of an impurity. Generally, the flash point is quoted for a chemically pure substance.

A spontaneous ignition temperature is the lowest temperature at which a substance will ignite spontaneously without an external source of ignition.

The boiling point of a substance is the temperature at which the vapor pressure of the liquid equals the pressure surrounding the liquid, causing the liquid to change into vapor.

Flash points may be altered by the presence of an impurity, so flash points may vary.

The word flammable has the same meaning as inflammable. Flammable is the term used throughout the DGR.

Flammable liquids are liquids, mixtures of liquids, or liquids containing solids in solutions or suspension that give off a flammable vapor at temperatures of not more than 60°C (140°F) in a closed-cup test or not more than 65.6°C (150°F) in an open-cup test, also referred to as the flash point. This also includes liquids offered for transport at temperatures at or above their flash point and substances that are transported at elevated temperatures in a liquid state and that give off a flammable vapor at a temperature at or below the maximum transport temperature.

Examples of flammable liquids include the following:

• Acetone
• Alcohols
• Gasoline
• Aviation fuel
• Kerosene
• Ethanol
• Butanol

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