Sheet materials. Determination of water vapour transmission rate (WVTR). Gravimetric (dish) method Ingestion-build-73073 BS 5642‑2

BS 5642‑2

and classification by green weight

equivalent to that of the defined reference condition

Their predilection for warm water means that they are capable of colonizing artificial water systems and equipment containing water

Sheet materials. Determination of water vapour transmission rate (WVTR). Gravimetric (dish) method Ingestion-build-73073 BS 5642‑21 Scope This document specifies a method for the determination of the water vapour transmission rate (often erroneously called permeability) of sheet materials. This method is not generally recommended for use if the transmission rate is expected to be less than 1 g m2 per day or for materials thicker than 3 mm. In such cases the method specified in ISO 9932 is preferred. The method cannot be applied to film materials that are damaged by hot wax or