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Hygric and Thermal Simulation

Under (vapor) pressure – condensation under indoor pool climate conditions

In his bachelor’s thesis Andreas Schmid of the East Bavarian Technical University of Applied Sciences Amberg-Weiden used HTflux for the hygrothermal assessment and optimization of construction details under exceptional climate conditions.

We are happy to publish an excerpt of his thesis here. The detail assessed shows the sill region of a window frame in a public swimming pool. Since the internal climate conditions depend very much on the specific building and climate control a measurement was carried out to determine these. The measurements showed an average temperature of 32,5°C and a relative humidity level of 50%. Due to the elevated temperature the relevant indoor water vapor partial pressure reaches an exceptional value of more than 2400 Pascals. Using the HTflux climate tool it can easily be determined, that under these conditions the air contains more than 17 grams of water per cubic meter and the dew-point temperature rises to more than 20 degree celsius(!).

Condensation on window frame under swimming pool climate conditions

Condensation at window sill region under swimming pool climate conditions, before and after restoration

Condensation can hardly be avoided under these conditions. The evaporative dry out potential is very limited, as even with summer temperatures there will be no relevant pressure gradient to the inside. It is therefore essential to ensure that condensation will only occur in non-critical regions (e.g. on glass surfaces). If condensation occurs in the interior of building components the risk of mold formation is high, and the condensate can negatively affect the properties of the insulation materials, exacerbating the situation even further…

Here is a link to the excerpt of the thesis of Mr. Schmid (unfortunately it’s available only in German):

Hygrothermische Analyse eines Sockelanschlussdetails in einem Schwimmbad mit HTflux nach den Vorgaben der Feuchteschutznorm DIN 4108-3