Durability of wood and wood-based products - Natural durability of solid wood - Guide to the durability requirements for wood to be used in hazard classes

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.

Dauerhaftigkeit von Holz und Holzprodukten - Natürliche Dauerhaftigkeit von Vollholz - Leitfaden für die Anforderungen an die Dauerhaftigkeit von Holz für die Anwendung in den Gebrauchsklassen

Dieses Dokument gibt eine Anleitung für die Auswahl von Holzarten basierend auf deren biologischer Dauerhaftigkeit und zur Auswahl von Holzmaterialien auf der Grundlage ihrer spezifisch erhöhten Resistenz gegen den Befall von holzzerstörenden Organismen (Holzschutzmittelbehandlung, Holzmodifikation und andere biozidfreie Verfahren), die als Vollholz, Holzwerkstoffe (z. B. Brettschichtholz) und als Holzverbundstoffe (z. B. Sperrholz, Holz-Polymer-Verbundwerkstoffe) in den in EN 335 definierten Gebrauchsklassen verwendet werden.
Diese Norm berücksichtigt nicht:
i)   die Dauerhaftigkeit des Klebstoffs, der in Holzwerkstoffen oder Holzverbundstoffen verwendet wurde;
ii)   die ästhetische Funktion von Holzprodukten (Verfärbung, Oberflächenverwitterung, Schimmel);
iii)   die verschiedenen Verfahren zum Schutz von Produkten, da diese basierend auf den Prioritäten des Anwenders und des Kunden und der Art des Produkts variieren, z. B. Brettschichtholz im Vergleich zu Sperrholz.

Durabilité du bois et des matériaux dérivés du bois - Durabilité naturelle du bois massif - Guide d'exigences de durabilité du bois pour son utilisation selon les classes de risque

Le présent document contient des recommandations relatives au choix d'essences de bois, d'après leur durabilité biologique, et au choix de matériaux dérivés du bois, d'après leur résistance améliorée spécifique aux attaques d'organismes lignivores (traitement par produit de préservation du bois, modification du bois et autres méthodes non biocides), pour l'emploi en tant que bois massif, produits transformés à base de bois (par exemple bois lamellé-collé) et composites dérivés du bois (par exemple contreplaqué, composites bois-polymères) dans les classes d'emploi définies dans l'EN 335.
La présente norme ne traite pas :
i)   des caractéristiques de durabilité de la colle utilisée dans les produits transformés à base de bois ou les composites dérivés du bois ;
ii)   de la fonction esthétique des produits en bois (discoloration, altération de la surface, moisissure) ;
iii)   de la stratégie de protection des produits étant donné qu'elle diffère en fonction des priorités de l'utilisateur et du client, et du type de produit (par exemple le bois lamellé-collé comparé au contreplaqué).

Trajnost lesa in lesnih izdelkov - Naravna trajnost masivnega lesa - Zahteve po trajnosti lesa, ki se uporablja v posameznih razredih ogroženosti

General Information

Status
Not Published
Publication Date
28-Jun-2020
Current Stage
4098 - Decision to abandon - Enquiry
Completion Date
18-Aug-2020

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SLOVENSKI STANDARD
01-januar-2019
Trajnost lesa in lesnih izdelkov - Naravna trajnost masivnega lesa - Zahteve po
trajnosti lesa, ki se uporablja v posameznih razredih ogroženosti
Durability of wood and wood-based products - Natural durability of solid wood - Guide to
the durability requirements for wood to be used in hazard classes
Dauerhaftigkeit von Holz und Holzprodukten - Natürliche Dauerhaftigkeit von Vollholz -
Leitfaden für die Anforderungen an die Dauerhaftigkeit von Holz für die Anwendung in
den Gebrauchsklassen
Durabilité du bois et des matériaux dérivés du bois - Durabilité naturelle du bois massif -
Guide d'exigences de durabilité du bois pour son utilisation selon les classes de risque
Ta slovenski standard je istoveten z: prEN 460
ICS:
79.040 Les, hlodovina in žagan les Wood, sawlogs and sawn
timber
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
November 2018
ICS 79.040 Will supersede EN 460:1994
English Version
Durability of wood and wood-based products - Natural
durability of solid wood - Guide to the durability
requirements for wood to be used in hazard classes
Durabilité du bois et des matériaux dérivés du bois - Dauerhaftigkeit von Holz und Holzprodukten -
Durabilité naturelle du bois massif - Guide d'exigences Natürliche Dauerhaftigkeit von Vollholz - Leitfaden für
de durabilité du bois pour son utilisation selon les die Anforderungen an die Dauerhaftigkeit von Holz für
classes de risque die Anwendung in den Gebrauchsklassen
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 38.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2018 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 460:2018 E
worldwide for CEN national Members.

Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Use class . 7
5 Durability classes . 7
6 Consequence of failure . 8
7 Material resistance in the various Use classes . 8
7.1 General . 8
7.2 Durability: wood-destroying fungi . 8
7.3 Durability: wood-destroying beetles . 11
7.4 Durability: termites . 11
7.5 Durability: marine organisms . 11
Annex A (informative) Important factors in the relationship between expected service life
and natural durability . 12
A.1 Service life . 12
Annex B (informative) Example of a factorisation approach for durability-based design and
service life prediction of timber structures . 13
Annex C (informative) Moisture dynamics . 16
C.1 General . 16
C.2 Treatability . 16
C.3 Moisture dynamics . 16
C.4 Test methods . 16
Annex D (informative) National interpretation of performance classes . 18
Annex E (informative) Consequence of Failure (CoF) . 19
Bibliography . 21

European foreword
This document (prEN 460:2018) has been prepared by Technical Committee CEN/TC 38 “Durability of
wood and wood-based products”, the secretariat of which is held by AFNOR.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 460:1994.
Compared to the current EN 460, the following modifications apply:
— general modifications.
Introduction
There is increasing need to understand and be able to communicate with users the service life of wooden
components, especially in construction. Service life in the Construction Products Regulations is
performance within an economically acceptable period, under normal exposure and normal
maintenance. It is usually considered to be how many years a construction component will provide
satisfactory function in its use environment. This standard is concerned with performance classification
for wood and wood-based products, the first building block for understanding service life for
construction products and other wood products.
Architects, construction engineers, the public, life cycle assessments (EN 15804) and other standards
(e.g. ISO 15686 series) require information on service life of construction products. Internationally wood
experts are currently developing methods and techniques to match data on durability of wood against
biological hazards with service life expectation, considering numerous influencing factors. As long as
reliable methods continue to be unavailable to prevent misleading interpretation of durability data and
to avoid unjustified expectations of service life the following is stated:
As for other materials wood in outdoor applications or exposed to high moisture content will age in a
distinct manner.
Wood utilized in the correct way can be in service for hundreds of years, as examples worldwide show.
At present due to the variety of conditions under which wood may be in service a direct, simple and
reliable deduction from durability classes to service life under real-use conditions is not available.
In addition to the durability against biological hazards service life depends on wood species, construction
details, climate, maintenance and many other issues.
The shorter the forecasting horizon the higher the probability that an estimated service life will be
reached in practice.
If wood-destroying organisms are likely to attack wood in service, a suitable pathway for meeting service
life needs to be selected. There are principally two pathways (i) by durability - either select a wood
species of sufficient natural durability or ensure the durability characteristics of the wood are enhanced
by treatment with a wood preservative, chemical modification or non-biocidal treatment to manage the
challenge presented in the use environment or (ii) by design for durability - minimizing the moisture risk
(or exposure dose) the wooden component is exposed to or by denying the access for organisms through
construction measures. Typically it is a combination of both to deliver a reasonable service life.
This standard allows a user to choose a wood or wood-based material for a product and knowing its
durability class alongside the use class of the end use environment establish a performance classification.
No attempt has been made to quantify the working life that could be expected from a particular
combination which is reflected in national interpretation documents (Annex D).
This standard includes scope for benchmark performance testing e.g. if the product performs better or
equal to the existing product in service, which can be used for CE marking purposes.

1 Scope
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.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies. For
undated references, the latest edition of the referenced document (including any amendments) applies.
EN 335:2013, Durability of wood and wood-based products — Use classes: definitions, application to solid
wood and wood-based products
EN 350, Durability of wood and wood-based products — Testing and classification of the durability to
biological agents of wood and wood-based materials
CEN/TS 16818, Durability of wood and wood-based products — Moisture dynamics of wood and wood-
based products
EN 599-1, Durability of wood and wood-based products — Efficacy of preventive wood preservatives as
determined by biological tests — Part 1: Specification according to use class
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp
3.1
benchmark performance
performance of an existing product well-known in the market place in that end use
3.2
biological durability
quality of resistance against wood destroying organisms
Note 1 to entry: This inherent resistance is due to the presence of natural components that can exhibit different
levels of toxicity towards biological organisms and/or to anatomical particularities or a specific constitution of
certain wood-based materials.
3.3
component
product manufactured as a distinct unit to serve a specific function or functions
3.4
consequence of failure (COF)
significance of the components failure in service expressed as a risk and a tolerance of that risk
3.5
critical biological hazard (CBH)
biological hazard or hazards that are most significant for the end use application and its geographical
location (see Annex E)
3.6
desired s
...

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