Impact of core thickness and opening height on the combustion characteristics of polyethylene sandwich panels

Polyethylene (PE) sandwich panels are being increasingly used in external building insulation, but they may also contribute to the upward spread of flames during fires. This work investigates the impact of core thickness and opening height on the combustion characteristics of PE sandwich panels. Small-scale experiments and numerical simulations show that flame stretching and intermittent flames occurr during combustion. The average flame spread height is proportional to the thickness and the opening height, and a dimensionless relationship between the flame height and the characteristic length is established. As the thickness increases, the high-temperature zone within the PE sandwich panels increases. The average mass loss rate is proportional to the thickness and opposite to the opening height. The findings of this study hold crucial theoretical significance for ensuring the safe design of windows and PE sandwich panels in high-rise buildings.