Wetting diffusivity
Assessing risks in insulation retrofits using hygrothermal software tools, Heat and moisture transport in internally insulated stone walls, by Joseph Little, Calina Ferraro and Beñat Arregi, published by Historic Environment Scotland in 2015, defines wetting diffusivity (Dws) as: ‘…the liquid transport coefficient for suction, measured in units of square metre per second (m2/s). It describes the capillary uptake of water when the imbibing surface is fully wetted. In the context of building physics this describes rain on a façade or an imbibition experiment. The suction transport is dominated by the larger capillaries, since their lower capillary tension is more than compensated by their markedly lower flow resistance.’
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