防耐火試験における包括熱伝導率を用いたせっこうボードの遮熱性予測

In this study, a prediction method of the unexposed surface temperature of a wall is proposed using "inclusive thermal conductivity" that takes into consideration heat and mass transfer in a material containing moisture. Inclusive thermal conductivity is estimated based on the results of temperature measurements from actual fire tests. The proposed method will enable the estimation of thermal conductivities of materials that are difficult to assess using conventional technologies. The inclusive thermal conductivities are estimated by using the finite differential method.The estimated thermal conductivities of gypsum board were based on the results of temperature measurements from actual fire test which was conformed in ISO834. On the estimation of the inclusive thermal conductivity, the calculated internal temperatures of the materials and exposed surface temperature on the non-heated side were compared with the experimental results. The inclusive thermal conductivities were estimated considering the moisture behavior and cracks in the materials.The inclusive thermal conductivities have some peaks and troughs at various temperatures. The inclusive thermal conductivity of gypsum board becomes larger as the temperature becomes higher. Furthermore, an approximate formalization of the inclusive thermal conductivities was conducted in order to use them in numerical calculations, they are segmented for each temperature region.In order to verify the usefulness of inclusive thermal conductivities for temperature prediction, the unexposed surface temperatures were predicted for decreasing material thicknesses of gypsum board. For changing specimen thickness, the inclusive thermal conductivities of predictive calculations were performed by removing layers of the same thickness as the divided layer.Calculations using this inclusive thermal conductivity sufficiently captured the temperature history. Unexposed surface temperature prediction is affected by the exposed surface temperature of the fire-resistance test, and that is a high accuracy as the difference of the material thickness is smaller. Exposed surface temperature obtained from the fire-resistance test result influenced the prediction of the unexposed surface temperature. The results confirmed that the inclusive thermal conductivity reflects the influence of moisture movement, evaporation of water, deterioration, or crack formation in the material at high temperatures.The prediction accuracy of numerical ana