STUDY ON PREDICTION METHOD FOR INSULATION OF TRIPLE-LAYER WALL USING “INCLUSIVE THERMAL CONDUCTIVITY” IN FIRE-RESISTANCE TEST

In this study, a method for predicting the unexposed surface temperature of triple-layer wall is proposed by using "inclusive thermal conductivity" which considers transfer of heat and moisture, and influence of occurring cracks and contained water in materials. In our previous studies, the unexposed surface temperature was predicted by using the inclusive thermal conductivity for single- and double-layer wall. In each case, more accurate temperature history was also obtained by this numerical calculation. The proposed method will enable the estimation of thermal conductivities of materials that are difficult to assess using conventional technologies. Fire-resistance tests were conducted on specimens with fiber-reinforced cement siding, insulation, and gypsum boards overlaid. Fire-resistance tests were conducted based on ISO834. Inclusive thermal conductivities are estimated based on the results of temperature measurements from fire-resistance tests. The inclusive thermal conductivities are calculated by using the finite differential method. The inclusive thermal conductivities of fiber-reinforced cement siding and gypsum board that were estimated in the study on the double-layer wall were examined whether it is possible to work well enough on the prediction for triple-layer. The inclusive thermal conductivity of the insulation was estimated using the inclusive thermal conductivities for the double-layer which were estimated in our previous study. On the estimation of the inclusive thermal conductivity, the calculated internal temperatures of the materials, temperature between materials, and unexposed surface temperature were compared with the experimental results. Additionally, on estimation of inclusive thermal conductivities the influence of the moisture behavior and cracks in the materials are considered. Since the inclusive thermal conductivities have some peaks and/or dips at various temperatures, they are approximated to polynomial approximation for each temperature region. In order to estimate that unexposed surface temperature of similar triple-layer specimen whose thickness of gypsum board layer is decreasing, the number of inclusive thermal conductivities are reduced. In the case of estimating the specimen thickness whose thickness is changed, the inclusive thermal conductivities of predictive calculations were performed by removing layers of the same thickness as the divided layer. The calculations using this inclusive thermal conductivity suff