Experimental methods for studying heat transfer in cable penetrations in case of fire

An experimental technique for studying the processes of heat transfer in cable penetrations under the thermal effects of fire is proposed. To study the influence of the design of cable penetrations on cable heating processes, three most common types of penetrations were selected. New experimental data on the dependence of the temperature of the structural elements of the cable and the penetration on time have been obtained. It is shown that the conductive core of the cable is the main element involved in the propagation of heat. The presence of an air space or a material that promotes intensive heat exchange in the cable penetration design leads to an increase in its fire resistance limit. It is determined that the cable penetration with the filling of the internal space with fire-fighting foam based on polyurethane foam is most susceptible to rapid heating and loss of fire resistance. Studies have shown that when assessing the fire resistance limits of cable penetrations, it is necessary to take into account the thermophysical characteristics of cables, their number, as well as the design features of cable penetrations.