Low heat of combustion

n. Caloric content of wildland fuel reduced by the latent heat absorbed when the water of reaction is vaporized.

 

  • Discussion

 

During a fire, the combustion reaction itself produces water which, when vaporized in the fire, absorbs heat. Thus, the high heat of combustion, such as that determined with a bomb calorimeter, must be reduced by this amount to obtain the low heat of combustion -- a standard value of 1263 kJ/kg of fuel is assumed for wildland fuels (Byram 1959).

 

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Low heat of combustion is further reduced by the latent heat of vaporization of the fuel's moisture content to estimate heat yield. A standard value of 24 kJ/kg per moisture content percentage point (Van Wagner 1972) accounts for this heat loss.