Effect of width on the fire spreading characteristics of PE metal sandwich panels under the action of double fire sources

The exterior walls of high-rise buildings typically contain substantial thermal insulation materials. Once ignited, these materials can readily induce major fire accidents. In this study, through the constructed reduced-size experimental bench to evaluate the effect of window overflow fire and upper chamber fire on the fire spreading properties of PE metal sandwich panels with different widths. The result shows that the average flame height and flame oscillation intensity increased with an increase in fire source power and sandwich panel width. Temperature curves exhibited a consistent trend under different working conditions. Dimensionless analysis of the sandwich layer temperature indicated that under specific fire source power conditions, the 60 cm sandwich panel reached the highest peak temperature and posed the greatest fire hazard. Based on the width and length of the preheating zone, a model for the rate of flame spreading was created. At a constant sample width, the accelerated spread of the upper part of the plate by the action of fire source B was more obvious. These conclusions are instructive for the study of building facade fire.