Study on Suppression of Dew Condensation for lnsulation made of Cellulose Fiber

两个同样大小的实验房屋（楼层：7 m^2）用纤维素纤维作为绝缘材料。一个房子（A房子）在墙的外侧有通风空间，而另一个房子（B房子）没有。7点至22点，室温和相对湿度分别调节为22‰和80%。这些规定分别保存2周和4周，每小时在每个房屋的40个点测量保温箱内的温度和相对湿度。得到以下结果：1)未检测到两个房屋之间的温度差异。2)对A住宅隔热层两侧的绝对湿度梯度进行了观测。保温层外侧的湿度高于保温层内侧。相反，B屋没有观察到湿度梯度。这一事实表明，水分通过绝缘材料传递。3) B住宅的顶棚以上保温层含水率比A住宅高近1.2倍。墙体的通风空间影响保温材料的含水率。在实验室中测定了纤维素纤维的透气性。保持保温两侧的绝对湿度恒定，并测量保温过程中的水蒸气传量。虽然纤维素纤维的水蒸气传递量取决于两侧湿度的不同，但玻璃纤维的水蒸气传递量没有表现出相同的趋势。纤维素纤维的透气性估计为1.9，与木纤维板的透气性几乎相同。测定了纤维素纤维对水分的吸附。

Two same sized experimental houses (floor : 7 m^2) were charged with cellulose fiber as insulation. One house (A house) has venting space on the outer side of the wall and the other (B house) has not.The room temperature and relative humidity were regulated at 22ﾟC and 80% from 7 to 22 o'clock. The regulations were kept for 2 and 4 weeks and the temperature, relative humidity in the insulation were measured in every hour at 40 points of each house. The following results were obtained :1) Differences in temperature between two houses were not detected.2) The absolute humidity gradient between both sides of the insulation were observed in A house. The humidity at the onter side of insulation was higher than that of inner side. On the contrary, no humidity gradient was observed in B house. This fact indicates that moisture transfer through the insulation.3) The moisuture content of the insulation above the cieling in B house was higher (nearly 1.2 times) than that of A house. Venting space in the wall affects to keep the moisture content in the insulation low.The vapor permeance of cellulose fiber was estimated in laboratory. Absolute humidity of both sides of the in sulation were kept constant and the amount of water vapor transfer during the insulation was measured.Though the amount of water vapor transfer through cellulose fiber depends on difference of humidity of both sides, that of glass fiber did not show same tendency. The vapor permeance of cellulose fiber estimated 1.9 and is nearly same value of the woodenn fiber board. The adsorption of moisture by cellulose fiber was also detected.