CEN/TC 38/WG 28 - Performance classification

This document gives guidance on the selection of wood and wood-based products for use in situations where they can be subject to degradation by fungi, wood destroying insects or marine borers. This guidance includes information on factors that can influence the service life of a wood or wood-based product when considering biological degradation. In many end uses, design, workmanship and maintenance will also influence the service life of the wood or wood-based product.
This document is a step toward the evaluation of the service life of a wood product.
This document does not consider:
1)   the durability characteristics of the glue used in wood-based products;
2)   the aesthetic function of wood products (discoloration, surface weathering, mould).

This document details a method for determining the water uptake and the effectiveness of the drying process on solid wood, wood-based materials or coated wood by means of water absorption and water vapour desorption. This document lays down a method to assess the moisture dynamics of wooden products which can be a contributing factor to the susceptibility to wood decay.

The scope of WG28 Performance Classification is expressed in this Technical Report:
Guidance on the determination of end use performance of wood products: utilization and improvement of existing test methods to estimate service life, in order to give input to the harmonized product standards dealing with the durability requirement of the CPD and future Regulation (EU) No 305/2011 (The Construction Products Regulation CPR).
This Technical Report brings together the evaluations and discussions to date that have occurred within CEN/TC38/WG28 Performance Classification.
This technical report does not address panel products specifically.

This document gives guidance on the selection of wood species based on their biological durability and selection of wood materials based on their specific enhanced resistance (wood preservative treatment, wood modification and other non-biocidal methods) to attack by wood-destroying organisms for use as solid wood, as engineered wood products (e.g. glulam) and as wood based composites (e.g. plywood, wood polymer composites) in the use classes defined in EN 335.
This standard does not consider:
i)   the durability characteristics of the glue used in engineered wood products or wood-based composites;
ii)   the aesthetic function of wood products (discoloration, surface weathering, mould);
iii)   the strategy for protection of products as it will be different based on priorities of the user and client and the type of product e.g. glulam compared to plywood.