Fireline Intensity
Fireline intensity is the heat energy released per unit time from a one-foot-wide (or one-meter-wide) section of the fuel bed extending from the front to the rear of the flaming zone. Fireline intensity is a function of rate of spread and heat per unit area, and is directly related to flame length.
In IFTDSS this is expressed in BTU/foot/second in the Map Studio and reports, in the download it is in kilowatt/meter.