Combustion and fire safety of energy conservation materials in building vertical channel: Effects of structure factor and coverage rate

Abstract

Experimental study on combustion and fire safety of energy conservation materials (extruded polystyrene, i.e., XPS) in vertical channel with front openings of building façade is conducted, and effects of channel structure factor (α) and curtain wall coverage rate (β) are revealed. The XPS flame in the vertical channel is turbulent. There is a correlation between the flame height and pyrolysis length: xf=mxpn, where m and n vary with the change in structure factor and coverage rate. Upward flame spread rate decreases first and then increases as β rises. When 0≤β<0.2, the restraining effect of vertical channel on air entrainment dominates, while for 0.2≤β≤0.8, the heat feedback from curtain wall dominates. When β = 0, the influence of α on flame spread rate is not significant. The flame spread rate increases with increasing α when 0.2≤β≤0.8. A model is established to predict the flame spread rate under different coverage rates and structure factors. Compared with experimental results, the prediction error is smaller than 10%. Larger values of flame height and flame spread rate correspond to higher fire hazard. This work is beneficial for fire safety assessment of building thermal insulation materials and optimal design of energy-saving curtain wall.