A basic study on characteristics of mold movement in glass wool heat insulating materials

It is necessary to insulate a building envelope in order to improve the indoor environment and to save energy consumption in houses. However, if vapor protection or an airtight seal is not perfect, condensation decreases the durability of the structure and lowers the indoor air quality. The air pollutants enter from concealed spaces (beam space, crawl space, etc.) to the indoor space through indoor decompression in the ventilation system. If mold infiltrates through the glass wool heat insulating materials, some of the mold may stay and grow. The objective of the present investigation is to characterize the movement of mold spores between heat insulators. It is concluded that the sampling method for the concealed space must use a Teflon tube that is about 0.3 m long. The heat insulator was washed using sterilized physiological salt solution to clarify the movement of mold spores in a heat insulator. The amount of mold spores in the heat insulator decreased with an increase in the number of times it was washed. After the third washing, the desorption rate of mold spores in the heat insulator was about 85%. Hence, three rounds of washing were required to measure the mold movement in glass wool heat insulators. For movement of mold spores inside the heat insulator, the quantity of mold spores adhering to the heat insulator decreases exponentially with an increase in length. In this range of the wind velocity, it was found that the movement of mold spores between insulators through the heat insulator is not significantly influenced by wind in the small chamber.