LAUSR

Abstract Gypsum board assemblies are important in preventing spread of flame and hot smoke, keeping escape routes available, and extending evacuation time. In general, heavier assemblies are expected to provide a higher degree of fire resistance, while low density board can reduce transportation and labor costs. The focus of this paper is to identify key model parameters that affect performance under fire conditions to enable design of lower weight board assemblies without compromising fire performance. A mathematical model was developed to estimate the thermal response of full scale 3-D gypsum wall assemblies subjected to ASTM E-119 furnace test conditions. The effect of insulation in the air cavity (including melting) was modeled. The estimated thermal response compared favorably with the measured experimental furnace test data. It was found that lots of factors were positively correlated with failure time. Among them, the board thickness, the activation energy of di-hydrate gypsum and hemi-hydrate gypsum had the most significant influence. When these factors were increased by 5% respectively, failure time was extended by 8.06%, 7.81% and 11.84% accordingly. Some factors were negatively correlated with failure time, such as the emissivity of anhydrous gypsum, the thermal conductivity and melt conductivity of insulation. Emissivity of the hemi-hydrate gypsum did not affect the failure time obviously.