N. Jensen, E. B. Møller, Kurt Kielsgaard Hansen, Carsten Rode
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引用次数: 0
Abstract
The present project investigated the hygrothermal performance and risk of mould growth in solid masonry walls retrofitted internally with three diffusion-open bio-based insulation materials (two loose-fill cellulose and one hemp fibre), installed in test containers with controlled indoor climate. Focus was on bio-based insulation materials, as these are upcoming due to necessary CO2 reductions and because the hygroscopic properties of bio-based materials are different from traditional insulation materials like mineral wool therefore, some manufacturers claim a vapour barrier is unnecessary, even in relatively cold climates. The project was a large experimental study in two reefer containers with reconfigured facades, in which solid masonry walls with embedded wooden elements were constructed. The study focused on the conditions in the masonry/insulation interface and in the embedded wooden elements. The effect of hydrophobization and different indoor moisture loads were also investigated. Moreover, the bio-based insulation systems were compared with a wall insulated with the traditional mineral wool and vapour barrier system. Relative humidity and temperature were measured at several locations in the test walls for 1 year and 9 months. Measurements show that exposed masonry walls retrofitted internally with diffusion-open bio-based insulation materials resulted in unacceptably high moisture levels (>80% RH over longer periods). Lower moisture levels were observed when the internal insulation was combined with hydrophobization against wind-driven rain, but unacceptably high moisture levels still occurred (60%–70% in summer and 95%–100% in winter in the interface). Hydrophobization reduced the moisture levels in the interface and embedded wooden elements only in walls facing southwest, which is the direction with the most wind-driven rain. Mould growth tests showed no growth in the interface in walls insulated with cellulose insulation (mycometer surface value <25). Meanwhile growth was found in all four walls insulated with hemp fibre matts (mycometer surface value >400).
期刊介绍:
Journal of Building Physics (J. Bldg. Phys) is an international, peer-reviewed journal that publishes a high quality research and state of the art “integrated” papers to promote scientifically thorough advancement of all the areas of non-structural performance of a building and particularly in heat, air, moisture transfer.