Heat transfer model for calculation of the temperature field inside thin-walled sections in fire

This paper introduces the heat transfer model for simple calculation of the temperature field inside thin walled sections in fire. It is dedicated for various shapes of a cross-section of structural elements made of metal. It utilizes the concept of an adiabatic surface temperature (AST) for determination of thermal boundary conditions. Due to the non-uniform heat exposure and arbitrary shape of the cross-section, the resulted temperature field is non-uniform. The given solution is valid for a transient heat transfer problem. The heat transfer model takes into account the practical abilities for measuring heat exposures both in experiments and numerical fire simulations and takes into account the inherent features of beam finite elements with stiffness integration at each step of an analysis, which is important for analyses of skeletal structures in fire. Finally, the heat transfer model is verified by comparison of results to the 2D finite element method solution and validated using data obtained from experiments.