DS CEN/TS 927-9:2023

Paints and varnishes - Coating materials and coating systems for exterior wood - Part 9: Determination of pull-off strength

Scope

This document specifies a method for assessing the resistance of a coating system on wet wood to separation from the substrate by measuring the force necessary to detach or rupture the coating system by a normal tensile strain applied through an attached stud (dolly). Additional information is gained by noting the type and locus of failure. The force required for detachment will depend on several factors including the adhesion of the coating to the substrate and between intermediate coating layers. The procedure is not regarded as a direct means of measuring adhesion but an indicator of adhesive performance (adherence) under wet conditions.
A procedure for wetting the wood substrate is described. The test method is only suitable for wood and wood-based substrates.
For dry adhesion the test method can be carried out without wetting, in which case it will differ very little from EN ISO 4624.