Burning Index
Encyclopedia
Burning Index is a number used by the National Oceanic and Atmospheric Administration (NOAA)
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 (NFDRS)
uses a modified version of Bryam's equation for flame length - based on the Spread Component (SC) and the available energy (ERC) - 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 (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.
National Oceanic and Atmospheric Administration
The National Oceanic and Atmospheric Administration , pronounced , like "noah", is a scientific agency within the United States Department of Commerce focused on the conditions of the oceans and the atmosphere...
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 (NFDRS)
National Fire Danger Rating System
-Background:John J. Keetch, a fire researcher in the southeast, wrote:"One of the prime objectives of the National Fire Danger Rating System is to provide as accurate a measure as possible of the relative seriousness of burning conditions and thereby, NFDRS can serve as an aid to fire control...
uses a modified version of Bryam's equation for flame length - based on the Spread Component (SC) and the available energy (ERC) - to calculate flame length from which the Burning Index is computed.
The equation for flame length is listed below:
where:
- j is a scaling factor,
- SC is the spread componentSpread ComponentSpread Component - The Spread Component is a rating of the forward rate of spread of a headfire. Deeming states that "the spread component is numerically equal to the theoretical ideal rate of spread expressed in feet-per-minute." This carefully worded statement indicates both guidelines and...
, - and ERC is the Energy Release ComponentEnergy Release ComponentThe Energy Release Component is a number related to the available energy per unit area within the flaming front at the head of a fire. Daily variations in ERC are due to changes in moisture content of the various fuels present, both live and dead...
.
Consequently, the equation for the Burning Index is:
where
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.