Fire Hazards of Façade Materials for Energy Conservation under Flashover

Abstract

Several fires had occurred in air-conditioned double-deck buses with energy-conserving façade foam materials in the past few years. Citizens in Hong Kong are now worrying whether they are safe while staying inside enclosures with energy-conserving foam materials. There are very few studies on evaluating the fire performance of façade materials. Solar heat gain control by using Overall Thermal Transfer Value in buildings would give shorter time to flashover. Flashover is hazardous in a room for fires with a sharp increase in burning rate and gas temperature. In this paper, nonlinear dynamics was used to study flashover in an example room using a two-layer zone model. A differential equation was set up to describe the rate of change of the layer temperature based on simple heat balance of the smoke layer. Evolution of the smoke layer temperature, equilibrium states of the system and their corresponding stabilities were then investigated.