Fireline Intensity Calculator

Tecnobosque Interactive Engineering Tool Explore wildfire fireline intensity in real time

Move the sliders and watch Byram’s fireline intensity update instantly from heat content, flaming fuel consumption and rate of spread.

Live calculation Interactive sliders Instant results Transparent equation

Interactive inputs Fire behaviour inputs

Drag any slider. The value and calculation update immediately.

Low heat of combustion H

MJ/kg

5 MJ/kg 30 MJ/kg

Flaming fuel consumption w

kg/m²

0.05 kg/m² 5 kg/m²

Rate of spread r

m/s

0.001 m/s 0.2 m/s

Illustrative examples

Live fireline intensity 360 kW/m 0.360 MW/m

Relative visual scale 360 kW/m

Logarithmic visualisation only. This is not an operational fire-behaviour or safety classification.

US customary 104.0 Btu/(ft·s)

Heat release along 10 m front 3.60 MW

Rate of spread 0.0200 m/s

If spread rate doubles 720 kW/m

18,000 × 1.000 × 0.0200 = 360 kW/m

Method Byram’s fireline intensity relationship

I = fireline intensity (kW/m)

H = low heat of combustion (kJ/kg)

w = flaming fuel consumption (kg/m²)

r = rate of spread (m/s)

I = H × w × r

Explore the equation

Move any slider above and the result changes immediately. Byram’s relationship is directly proportional to all three variables, so increasing one input while holding the others constant increases calculated fireline intensity by the same proportion.

Worked default example

With a low heat of combustion of 18 MJ/kg, flaming fuel consumption of 1 kg/m² and rate of spread of 0.02 m/s:

18,000 × 1 × 0.02 = 360 kW/m

Important limitation

Important: this calculator is intended for educational, analytical and engineering exploration. It is not an operational wildfire forecast and must not be used for evacuation, suppression or emergency safety decisions.