Fire parameters, behaviour, and comparative thermal hazard of food grains based on the cone calorimeter tests

Abstract

Agricultural food grains have been involved in various large fires, but little is known about the fire parameters for many varieties required to evaluate their fire hazard. This research experimentally studied various food grains, with an emphasis on African food grains to obtain their important fire parameters. Oven-dried cowpea, lentils, millet, soybean, flax (linseed), unshelled peanuts, sunflower, shelled peanuts, and sesame were subjected to heat fluxes of 25 kW/m2, 35 kW/m2, and 50 kW/m2 in a cone calorimeter. Heat release rate, effective heat of combustion, mass loss, critical heat flux, time to ignition, peak heat release rate, total heat release, and time to peak heat release rate were obtained. Thermal fire hazard indices derived from these primary parameters, such as flashover potential, fire growth rate, and percentage mass loss were determined and compared with wood pellets. Under a 50 kW/m2 heat flux, the peak heat release rate ranged from 230 to 608 kW/m2 for millet and sunflower respectively. The correlation of materials characteristics and fire parameters shows that the oil content is the dominant determinant of the thermal fire hazard level in the food grains tested. These grains were also found to have a higher fire hazard compared to wood pellets.