DIN EN ISO 7783:2012-02

ISO 7783 is one of a series of standards dealing with the sampling and testing of paints, varnishes and related products. The standard describes a method for determining the water-vapour transmission rate of self-supporting and nonself-supporting coatings. The water-vapour transmission rate is not necessarily a linear function of film thickness, temperature or relative humidity difference. A determination carried out under one set of conditions will not necessarily be comparable with one carried out under other conditions. Therefore, it is essential that the conditions of test are chosen to be as close as possible to the conditions of use. Water-vapour transmission is of greatest interest under conditions of high humidity. For this reason, the wetcup method has been adopted as the reference method. By agreement, other procedures and conditions, like the dry-cup method, may be used. This International Standard specifies a method for determining the water-vapour transmission properties of coatings of paints, varnishes and related products. It supplements ISO 12572. As far as possible, the procedure, the definitions and the calculations have been taken over from ISO 12572. It is recommended that ISO 12572 be consulted, if necessary, to obtain a better understanding of the procedure specified in this standard. The committee responsible for this standard is NA 002-00-15 AA "Bautenbeschichtungen" ("Coatings for masonry") at DIN.