For our expert software WINISO® for the calculation of heat flows, thermal bridges, isotherms and Uf values according to EN ISO 10077-2:2018 the add-on “Humidity” is available for the calculation of relative humidity, vapour diffusion and condensation water failure.
The following evaluation modes are available with the “Humidity” add-on:
Relative humidity fields
The display provides information about the quality of the profile/component. The darker the spots in the profile, the greater the relative humidity, i.e. the risk of condensation. The calculated value Psat is the saturation vapour pressure at the point in the component. It is temperature-dependent and indicates the maximum amount of water the component can absorb in Pa at the respective point.
Pi is the partial water vapour pressure at the respective point. The partial pressure is adjusted by the boundary conditions and the heat transfer in components and cavities. If the partial pressure exceeds the saturation pressure, the component is “supersaturated” at the point in consequence condensation water precipitates.
Vapour diffusion flow fields
It shows how much water in g/m*d flows through a component. The water vapour flow runs through a component in the same way as the temperature curve. This means that the water vapour flows along the partial pressure gradient from high to low. The resistance number μ is decisive for the diffusion current through a component. The larger the number, the more impermeable the building material is.
If the partial pressure Pi exceeds the saturation vapour pressure Psat, condensation occurs in the profile. Common causes are low temperatures and low diffusion resistance figures μ of the individual components. Places where condensation precipitates are marked in blue.