Temperature and Thermal Stress Simulation of Window Glass Exposed to Fire

Abstract

In a compartment fire environment, the high temperature encountered could induce important stresses in glass panes, resulting into cracks and possible fallout of the glazing. The aim of the present work is to investigate thermal stress distributions in a glazing system for fire scenarios. A two dimensional glass thermal stress model to calculate the transient temperature and thermal stress distributions in a typical window glass under fire conditions was developed based on the Kong's work. The basic thermal conduction equation and thermal stress equation for glass were discretized by using the Galerkin method. A computer program based on the model was also developed. For validation purposes, simulations have been carried out using literature experimental data on glazing behavior in an enclosure fire. The glass surface temperature (exposed side) and thermal stress distributions in the glass pane were calculated. The simulation results of the transient temperature and thermal stress are overall in line with the experimental data reported in literature. The major principal thermal stress distribution in the glass at the time of first crack is consistent with the experimental crack patterns. The calculated maximum stress is located at the top edge of the glass pane, as the first crack recorded by experiments. The model does not predict second or later cracks. These results illustrate the relatively good predictions and usefulness of the developed simulation code.