A flammable liquid is a liquid with flash point

Flash point

The flash point of a volatile material is the lowest temperature at which it can vaporize to form an ignitable mixture in air. Measuring a flash point requires an ignition source...

 of not more than 60.5°C (141°F), or any material in a liquid phase

Liquid

Liquid is one of the three classical states of matter . Like a gas, a liquid is able to flow and take the shape of a container. Some liquids resist compression, while others can be compressed. Unlike a gas, a liquid does not disperse to fill every space of a container, and maintains a fairly...

 with a flash point at or above 37.8°C (100°F).

Divisions

Class 3: Flammable Liquids

A flammable liquid

Flammable liquid

Generally, a flammable liquid is a liquid that can catch fire.In the USA, there is a precise definition of flammable liquid as one with a flash point below 100 degrees Fahrenheit. Less-flammable liquids are defined as combustible liquids...

 is a liquid having a flash point of not more than 60.5°C (141°F), or any material in a liquid phase with a flash point at or above 37.8°C (100°F) that is intentionally heated and offered for transportation or transported at or above its flash point in a bulk packaging. The following exceptions apply:

1. Any liquid meeting one of the definitions specified in 49CFR 173.115.
2. Any mixture having one or more components with a flash point of 60.5°C (141°F) or higher, that make up at least 99 percent of the total volume of the mixture, if the mixture is not offered for transportation or transported at or above its flash point.
3. Any liquid with a flash point greater than 35°C (95°F) which does not sustain combustion according to ASTM 4206 or the procedure in Appendix H of this part.
4. Any liquid with a flash point greater than 35°C (95°F) and with a fire point
   Fire point
   The fire point of a fuel is the temperature at which it will continue to burn for at least 5 seconds after ignition by an open flame. At the flash point, a lower temperature, a substance will ignite briefly, but vapor might not be produced at a rate to sustain the fire...
   
    greater than 100°C (212°F) according to ISO 2592.
5. Any liquid with a flash point greater than 35°C (95°F) which is in a water-miscible solution with a water content
   Water content
   Water content or moisture content is the quantity of water contained in a material, such as soil , rock, ceramics, fruit, or wood. Water content is used in a wide range of scientific and technical areas, and is expressed as a ratio, which can range from 0 to the value of the materials' porosity at...
   
    of more than 90 percent by mass.

Flash Point: The flash point is the minimum temperature at which a liquid gives off vapor within a test vessel in sufficient concentration to form an ignitable mixture with air near the surface of the liquid.

Placards

Alternate Placards and Labeling

• Combustible Liquids:
  • A combustible liquid means any liquid that does not meet the definition of any other hazard class
    Dangerous goods
    Dangerous goods are solids, liquids, or gases that can harm people, other living organisms, property, or the environment. They are often subject to chemical regulations. "HazMat teams" are personnel specially trained to handle dangerous goods...
    
     specified in this subchapter and has a flash point above 60.5°C (141°F) and below 93°C (200°F).
  • A flammable liquid with a flash point at or above 38°C (100°F) that does not meet the definition of any other hazard class may be reclassed as a combustible liquid. This provision does not apply to transportation by vessel or aircraft, except where other means of transportation
    Mode of transport
    Mode of transport is a term used to distinguish substantially different ways to perform transport. The most dominant modes of transport are aviation, land transport, which includes rail, road and off-road transport, and ship transport...
    
     is impracticable. An elevated temperature material that meets the definition of a Class 3 material because it is intentionally heated and offered for transportation or transported at or above its flash point may not be reclassed as a combustible liquid.
  • A combustible liquid which does not sustain combustion is not subject to the requirements of this subchapter as a combustible liquid. Either the test method specified in ASTM 4206 or the procedure in Appendix H of this part may be used to determine if a material sustains combustion when heated under test conditions and exposed to an external source of flame.

• Gasoline: This placard is an alternative placard, which may be used for gasoline
  Gasoline
  Gasoline , or petrol , is a toxic, translucent, petroleum-derived liquid that is primarily used as a fuel in internal combustion engines. It consists mostly of organic compounds obtained by the fractional distillation of petroleum, enhanced with a variety of additives. Some gasolines also contain...
  
   in non-bulk quantities.
• Fuel Oil: This placard is an alternative placard, which may be used for fuel oil
  Fuel oil
  Fuel oil is a fraction obtained from petroleum distillation, either as a distillate or a residue. Broadly speaking, fuel oil is any liquid petroleum product that is burned in a furnace or boiler for the generation of heat or used in an engine for the generation of power, except oils having a flash...
  
  in non-bulk quantities.