Determination of water vapour transmission properties
- Product Code: IN025
Standard : EN 12086,
EN 13469
This equipment and procedures for determining the water vapour transmission
rate, water vapour permeance and water vapour permeability of test specimens in
the steady state under different sets of specified test conditions. It is
applicable to thermal insulating products.
It is intended to be
used for homogeneous materials and for products which may contain integral
skins or facings of different material(s).
A material is
considered to be homogeneous, with regard to mass distribution, if its density
is approximately the same throughout, i.e. if the measured density values are
dose to its mean density.
This test method is
not normally used for determining the water vapour transmission properties of
single, separate vapour barriers (of high diffusion resistance), such as
prefabricated films, foils, membranes or sheets, due to the long duration of
the test.
For products with a
vapour retarder or barrier with a water vapour diffusion equivalent air layer
thickness Sd ≥1000 m other test methods e.g. IR-detection can be used for
measuring the single separate vapour retarder or barrier, provided that the
results obtained are in the same range as the values measured in accordance
with this standard.
The water vapour
transmission rate and permeance values are specific to the test spedmen (i.e.
the product) thickness tested. For homogeneous products, the water vapour
permeability is a property of the material.