How can ignition sources be characterized?

Ignition sources can be characterized as piloted and autoignition sources. Piloted ignition refers to instances where an external heat source, such as a flame, spark, or heat from another source, initiates the combustion of fuel. For example, striking a match or a spark from electrical equipment can create a piloted ignition.

On the other hand, autoignition occurs when a fuel ignites without the need for an external ignition source, solely due to the heat generated by compression or other conditions. An example of this would be in internal combustion engines where the air-fuel mixture ignites due to the heat generated by compressing the mixture in the cylinder.

This characterization is crucial in fire investigation because determining the type of ignition source can help in understanding how a fire started and how different materials behave under various conditions. By differentiating between piloted and autoignition sources, investigators can better assess fire scenarios and develop strategies for fire prevention and safety. This is why the answer that identifies these two categories as the basis for characterizing ignition sources is correct.