Radiation-conduction heat transfer in fibrous heat-resistant insulation under thermal effect

The conjugate diffusion model of radiation transfer and the approximation of radiant thermal conductivity are used to investigate the radiation-conduction heat transfer in a flat layer of fibrous heat-resistant insulation under the effect of fire. The results of calculation of the characteristics of unsteady-state heat transfer and of the duration of heat resistance of the substrate demonstrate the accuracy of the approximation of radiant thermal conductivity which is good for practical applications. The fireproof efficiency of fibrous quartz heat insulation is investigated. The calculation results demonstrate that the application of this insulation provides for high limits of fire resistance of metal structures.