The extinction of hydrocarbon flames based on the heat‐absorption processes which occur in them

An empirical relation has been developed which correlates and predicts the fire‐suppression effectiveness of a wide variety of gaseous, liquid and solid agents. The flame‐extinguishment model is based on the premise that extinction is dominated by heat‐absorption processes and that a flame is extinguished when sufficient heat has been removed by the extinguishant to reduce the temperature to a limit value. This limit value. This limit is the minimum temperature at which the effective rate of the combustion reactions is sufficient to maintain flamepropagation, and it depends in a predictable way on the properties of the suppressant and flame system. The heat‐balance equation describing this is derived in two stages. In the first, a preliminary equation is obtained by considering only those substances which are thermally stable and act only as heat‐capacity sinks. In the second, the equation is generalized by consideration of all endothermic reaction sinks, e.g. vaporization, dissociation and decomposition. The general equation correlates most of the extinction data found in the literature. The results suggest that for most substances the extinguishing capacity is related to heat‐extraction data found in the literature. The results suggest that for most substances the extinguishing capacity is related to heat‐extraction and that many of the effects previously attributed to chemical mechanisms may be thermodynamic in nature rather than kinetic.