Improvements on Wall Construction in order to Prevent the Condensation in a Wall and an Evaluation of them.

Research Project

Project/Area Number	62560162
Research Category	Grant-in-Aid for General Scientific Research (C)
Allocation Type	Single-year Grants
Research Field	林産学
Research Institution	Gunma University
Principal Investigator	KATO Koichi Gunma University・Associate Professor, 教育学部, 助教授 (80126846)
Co-Investigator(Kenkyū-buntansha)	UEDA Masafumi Gunma University・Professor, 教育学部, 教授 (50008116)
Project Period (FY)	1987 – 1988
Project Status	Completed (Fiscal Year 1988)
Budget Amount *help	¥1,900,000 (Direct Cost: ¥1,900,000) Fiscal Year 1988: ¥500,000 (Direct Cost: ¥500,000) Fiscal Year 1987: ¥1,400,000 (Direct Cost: ¥1,400,000)
Keywords	Condensation / Condensation in a wall / Moisture Conductivity / Simultantaneous heat and moisture transfer equations / Air layer / 恒温恒湿層 / 恒温恒湿槽 / 水分拡張係数
Research Abstract	To establish a planning method of a moisture-protected wall, we examined the influence of wall construction on the condensation process in a wooden wall and expressed that process by a simultantaneous heat and moisture transfer equations. The results obtained are as follows: 1) The transfer coefficients contained in the equations haven't been measured about woods and wooden materials. We measured the moisture conductivity under moisture content-gradients or temperature-gradients about several wall materials, and applied the equations to a drying process of wood and a condensation process in a single layer wall. The calculated values of moisture content in the material were nearly equal to the observed values. Therefore, it was recognized that the equations became a useful method to evaluate the condensation process. 2) The condensation process in the three layers walls which were constructed with two plates and an air layer between them were examined. We expressed an air layer by a mathematical model which is equivalent to moisture or hear transfer coefficient, and calculated the condensation process in a wall numerically. The influences of wall materials, thickness of an air layer, and the situation of a vapor barrier installed were investigated. It was recognized that a wall which hadn't a varrier on the exterior tended to avoid the moisture condensation. The calculated values of temperature agreed with the observed values. However, the caluculated values of the relative humidity in an air layer didn,t agree with observed values. 3) Several constant humidity boxes by using the saturated salt solution were examined in connection with the studies mentioned above. Some technical results were obtained about getting a constant humidity.