DIN Standards Committee Coatings and Coating Materials
DIN CEN/TS 16498
; DIN SPEC 91032:2014-02
Paints and varnishes - Coating materials and coating systems for exterior wood - Assessment of tannin staining; German version CEN/TS 16498:2013
Beschichtungsstoffe - Beschichtungsstoffe und Beschichtungssysteme für Holz im Außenbereich - Beurteilung von unerwünschten Verfärbungen aufgrund von Holzinhaltsstoffen; Deutsche Fassung CEN/TS 16498:2013
Procedure
VN
Overview
Coatings on exterior wood surfaces have both decorative and protective functions. A valued function of the coating system is to protect against discoloration caused by the presence of wood extractives in the coating migrating from the wood material. This Technical Specification (CEN/TS 16498:2013) specifies a test method for assessing the discoloration of coatings on wood by tannin staining due to wood extractives. The method uses an extract from Merbau wood as an indicator. Bleeding of wood extractives is assessed at two specified stages firstly after coating application and secondly after cyclic climate exposure. A qualification of colour differences that can be attributed to three different causes, bleeding of extractives, low opacity of the coating film or general yellowing in climate exposure, is included. This document does not specify acceptance values for colour differences that can be tolerated and it is not applicable to staining caused by knots for which there is a different test method (e. g. CEN/TS 16359). The committee responsible for this standard is NA 002-00-15 AA "Bautenbeschichtungen" ("Coatings for masonry") at DIN.
Document: references other documents
Responsible national committee
NA 002-00-15 AA - Coatings for masonry
