Burning Index
Burning Index is a number used by the National Oceanic and Atmospheric Administration to describe the potential amount of effort needed to contain a single fire in a particular fuel type within a rating area. The National Fire Danger Rating System uses a modified version of Bryam's equation for flame length – based on the Spread Component and the available energy – to calculate flame length from which the Burning Index is computed.
The equation for flame length is listed below:
where:
Consequently, the equation for the Burning Index is:
where is the Burning Index scaling factor of. Therefore, dividing the Burning Index by 10 produces a reasonable estimate of the flame length at the head of a fire. A unique Burning Index table is required for each fuel model.
