Burning Index (BI)

A number relating to the potential amount of effort needed to contain a single fire in a particular fuel type within a rating area. NFDRS uses a modified version of Bryam's equation for flame length - based on the Spread Component (SC) and the available energy (ERC) - to calcuate flame length from which the Burning Index is computed.

The equation for flame length is listed below:

F_L=j[(SC/60)(25(ERC))]^0.46

where (j) is a scaling factor, (SC) is the spread component, and (ERC) is the energy release component.

Consequently, the equation for the Burning Index is:

BI=j₁*F_L

where j1 is the Burning Index scaling factor of (10/ft). 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 (BI) table is required for each fuel model.

References