BSI PD CEN/TS 16498:2013
$102.76
Paints and varnishes. Coating materials and coating systems for exterior wood. Assessment of tannin staining
| Published By | Publication Date | Number of Pages |
| BSI | 2013 | 16 |
This Technical Specification 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).
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 4 | Contents Page |
| 5 | Foreword |
| 6 | Introduction |
| 7 | 1 Scope 2 Normative references 3 Terms and definitions 4 Apparatus and materials |
| 8 | 5 Procedure 5.1 Preparation of wood extract |
| 9 | Figure 1 — Extraction model 5.2 Wood panels, extract application and sealing |
| 10 | Figure 2 — Drawing of sample with wood extract applied on a part of the test surface (regions for colour measurements) 5.3 Coating application 5.4 Colour measurements after coating application |
| 11 | 5.5 Cyclic climate exposure 5.6 Colour measurements after cyclic climate exposure 5.7 Calculation and assessment of colour differences Table 1 — Assessment of colour measurements in phases of extract bleeding; colour differences; end condition minus standard (regions R and S according to Figure 2) |
| 12 | Table 2 — Assessment of colour measurements in phases of extract bleeding; qualification of bleeding of extracts 6 Test report |
| 13 | Bibliography |
