Numerical Methodology for Thermal-mechanical Analysis of Fire Doors

The certification process of a fire door implies that the structure is subjected to a standard fire test, to evaluate its resistance to thermal load. In particular, the door must fulfil specific requirements, such as, that the gaps among the door labyrinths and frame are able to stop flame propagation and that the mean and maximum temperature on the unexposed surface does not exceed defined values. The present paper describes the numerical methodology used to assess the fire performance of large fire doors (single leaf and double-leaf sliding doors), having a length of the order of 15-25m, commonly used for civil/industrial applications. These fire doors cannot be tested at lab scale, due to their size, and the only way to verify their structural integrity when subjected to fire is via numerical simulations. This paper presents the numerical methodology developed for verifying thermo-structural response of fire door starting from results of laboratories tests on specimen fire doors. The aforementioned methodology, based on the use of the Finite Element Method (FEM), foresees, first, the implementation of a coupled thermal-structural analysis on the 3D FE model of the specimen fire door, to predict the evolution of the distribution of temperature and deformations, to be validated with the values obtained from a set of thermocouples during the experimental tests. Then, the second step is the thermal-structural analysis on the FE model of the full scale fire door using the same materials and simulations’ parameters used for the specimen fire door’s model. The experience carried out for different configurations of door for various applications confirms the procedure is valid and reliable.