Flame Length Calculator

Flame Length Calculator: Estimate Visible Flame Height

Predicting how tall a flame will rise above a burner or fire source matters for clearance design, hazard assessment, and combustion chamber sizing. This calculator uses the Heskestad correlation, a well-established relationship from fire dynamics that relates flame height to heat release rate and source diameter.

The Formula

L = 0.235 × Q^0.4 − 1.02 × D

Worked Example

A burner releases 1,000 kW of heat from a 0.5 m diameter base.

L = 0.235 × 1,000^0.4 − 1.02 × 0.5 = 3.21 m

How to Use This Calculator

1. Enter the heat release rate in kW.
2. Enter the base diameter of the burner or fire source in meters.
3. Click Calculate to see the estimated flame length in meters.

Related Calculations

Combine with the Heat Release Rate Calculator to determine the input needed for this formula.