Euroview 70 Technical Manual - West Coast Vinyl Windows

- 2°C
1°C
4°C
7°C
10°C
12,6°C
16°C
- 2°C
1°C
4°C
7°C
10°C
12,6°C
16°C
7.1.2.3 Water vapour diffusion
In gases, liquids and even in solid bodies a concentration
balance occurs, which is dependent, among other things, on
temperature, the difference of pressure and concentration.
This concentration balance is called diffusion.
A high water vapour partial pressure and the high tempera-
ture in the interior cause water vapour diffusion from the
interior through the building envelope to the outside.
outside -5°C
inside +20°C
outside -5°C
inside +20°C
WITHIN THE QKE · WWW.GKFP.DE
Construction basics
Each material of the building envelope opposes water vapour
current by an amount, which is characterised by the water
vapour diffusion resistance factor μ of the material con-
cerned. The smaller the μ-factor, the more water vapour can
diffuse through the material (see chart 9).
Fig. 38: Concrete wall with
external thermal in-
sulation composite
system, plastic win-
dow with concrete
flush in the front
Fig. 39: Concrete wall with
external thermal
insulation compos-
ite system, plastic
window in centre,
reveal insulation
Chapter
7
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