1 Scope
This document specifies the equipment and procedure for determining the water vapour
transmission properties in the steady state under specified test conditions for test
specimens of preformed pipe insulation. It is applicable to thermal insulating products.
It is intended to be used for homogeneous materials (see NOTE below) and for products
which can have integral skins or adhered facings of some different material.
NOTE A material is considered to be homogeneous in terms of mass distribution if its density
is approximately the same throughout, i.e. if the measured density values are close
to its mean density.