Flammability Characteristics of Vehicle Fluids

The flammability characteristics of fluids are measured by standard laboratory tests. The procedures for these tests are rigorously defined to maximize repeatability of the measurements. Researchers have also performed tests of flammability properties of vehicle fluids in conditions more similar to those found in real-world vehicle fires. The results of both laboratory and real-world testing together provide the investigator with an understanding of the range of possible fire characteristics for the fluids of interest.

Standardized tests of flammability characteristics

Before presenting flammability data, it will be helpful to review the vocabulary used to characterize the fluids.

Flash point: The minimum temperature at which the liquid gives off sufficient vapor to form an ignitable mixture with air. (At flash point, there may not be sufficient vapor produced to sustain a fire after the vapors are ignited.)

Autoignition: The lowest temperature at which a substance ignites without the aid of an external energy source such as spark or flame.

Fire point: The minimum liquid temperature for which sustained burning of the liquid occurs after ignition of vapors. (Fire point is slightly higher than flash point.)

Flammability limits: Flammability requires a fuel and oxygen together. Flammability limits are the boundaries of high and low fuel concentration, within which flammability is possible.

Combustible fluid: A fluid with a flash point above 100 degrees F.

Flammable fluid: A fluid with a flash point below 100 degrees F.

For more detailed descriptions of the definitions and information about the standardized tests used to measure the values, click here.