The Development of Hazardous Conditions in Enclosures with Growing Fires

Abstract

A mathematical model for stimulating the environment in enclosures during the growth stage of hazardous fires was developed previously. To use the model one must specify the energy release rate of the fire, certain heat transfer parameters, the area and height of the enclosure and the elevation of the fire above the floor. Solution to the model’s equations would yield the timevarying thickness, temperature, and product of combustion concentrations of an upper smoke layer which starts to drop from the enclosure ceiling at the time of ignition. In this paper the model equations are solved for the general class of fires whose energy release rate, Q, and product of combustion generation rates, C, are approximately proportional to tⁿ (t is time and n≥0).For such fires, general results for the complete solution history of the enclosure environment are obtained and presented in the form of graphs, and, where possible, by closed form analytic expressions. ∪se of the results is illustrated in two example problems. The first of these involves a problem in smoldering combustion where, according to experimental data, the combustion zone can be simulated by an n=1 fire. The second involves a prediction of the environment produced in an enclosure which contains an n=2 fire, which simulates a specific, large-scale, flaming fire hazard.