cen:proj:73036

prEN 927-12, Paints and varnishes — Coating materials and coating systems for exterior wood — Assessment of tannin staining using water immersion test cen:proj:73036

Scope

This Technical Specification specifies a test method using water immersion test for assessing the
discoloration of coatings on tannic wood (oak, chestnut) by tannin staining due to wood extractives. Leachates of coated and uncoated wood are collected after the immersion procedure and their colour is compared. The colour of the coated wood before and after immersion tests is also compared. 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.