Effective Heat of Combustion for Flaming Combustion of Mediterranean Forest Fuels

An adapted bench-scale Mass Loss Calorimeter (MLC) device is proposed for evaluating effective heat of rapid flaming combustion of fine Mediterranean forest fuels. The MLC apparatus uses a calibrated thermopile to quantify heat release rate (HRR) as an alternative to the classical oxygen consumption measurement. A porous holder was used to simulate rapid flaming combustion. Average effective heat of combustion (AEHC) during the flaming phase was related to the classical measurement of gross heat of combustion (GHC) obtained in oxygen bomb calorimeter. Results showed that the effective heat of combustion (oven-dry basis) was between 18% and 44% lower than the gross heat of combustion. A linear regression was obtained (r(2) = 0.48; SEE = 1.25; p < 0.01; n = 26) to relate AEHC and GHC values. The simple model developed (AEHC = GHC - 6.75) suggests the possibility of reducing the heat of combustion values used in forest fire behaviour models for Mediterranean forest fuels.