Interlaboratory comparison for a laboratory leaching test procedure with façade coatings

Façade coatings are exposed to weathering. Driving rain events can cause façade runoff bearing the potential to release substances from the coating. In order to derive reliable and reproducible information about this so-called leaching (emission into water), a laboratory test method has been developed, that has been published as European Standard EN 16105:2011. An interlaboratory comparison has been performed with 8 participants in order to validate the test method. This article describes the test results that reveal statistics on the quality of the test method and allows further insights to the leaching mechanism in coatings.

► EN 16105 is a method to measure emissions of substances from façade coatings.
► The results of an interlaboratory comparison for EN 16105 are presented.
► EN 16105 is reproducible between laboratories and repeatable within laboratories.
► Analysis of dry films does not reveal reliable leaching data.
► Leaching is diffusion controlled and correlates with physico-chemical parameters.