1、BRITISH STANDARD BS EN 460:1994 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 The European Standard EN 460:1994 has the status of a British Standard UDC 674.03:620.193.8:620.193.91BSEN 460:1994 T
2、his British Standard, having been prepared under the directionof the Technical Sector Board for Building and Civil Engineering, was published underthe authority ofthe Standards Board and comes into effect on 15 August 1994 BSI 07-1999 The following BSI references relate to the work on this standard:
3、 Committee reference B/515 Draft for comment 91/51885 DC ISBN 0 580 22911 4 Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries: Austria Oest
4、erreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standard Finland Suomen Standardisoimisliito, r. y. France Association franaise de normalisation Germany Deutsches Institut fr Normung e.V. Greece Hellenic Organization for Standardization Iceland Technological Inst
5、itute of Iceland Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portugus da Qualidade Spain Asociacin Es
6、paola de Normalizacin y Certificacin Sweden Standardiseringskommissionen i Sverige Switzerland Association suisse de normalisation UnitedKingdom British Standards Institution Amendments issued since publication Amd. No. Date CommentsBS EN 460:1994 BSI 07-1999 i Contents Page Cooperating organization
7、s Inside front cover National foreword ii Foreword 2 Text of EN 460 3 National annex NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross-references Inside back coverBS EN 460:1994 ii BSI 07-1999 National foreword This British Standard has been prepared und
8、er the direction of the Technical Sector Board for Building and Civil Engineering and is the English language version of EN460:1994 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, published by the
9、 European Committee for Standardization (CEN). EN460 was produced as a result of international discussion in which the UnitedKingdom took an active part. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their co
10、rrect application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, theEN title page, pages2to6, an inside back cover and a back cover. This standard has been u
11、pdated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 460 May 1994 UDC 674.03:620.193.8:620.193.91 Descriptors: Wood, tests, durability, classifications, biode
12、gradability, hazards, pest resistance 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 Durabilit du bois et des matriaux drivs du bois Durabilit naturelle du bois massif Guide dexige
13、nces de durabilit du bois pour son utilisation selon les classes de risque Dauerhaftigkeit von Holz und Holzprodukten Natrliche Dauerhaftigkeit von Vollholz Leitfaden fr die Anforderungen an die Dauerhaftigkeit von Holz fr die Anwendung in den Gefhrdungsklassen This European Standard was approved by
14、 CEN on 1994-05-18. 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. Up-to-date lists and bibliographical references concerning such national standards
15、may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists 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 C
16、entral Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. CEN Europea
17、n Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1994 Copyright reserved to CEN members Ref. No. EN460:1994 EEN460:1994 BSI 07-1999 2 Foreword This European Standard has been drawn up by WG2 “Natura
18、l durability” of Technical Committee CEN/TC38, Durability of wood and wood-based products, with AFNOR as Secretariat. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November1994, and conflicting
19、national standards shall be withdrawn at the latest by December 1996. This European Standard was adopted by CEN and in accordance with the Common CEN/CENELEC Rules, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Ice
20、land, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and UnitedKingdom. Contents Page Foreword 2 Introduction 3 1 Scope 3 2 Normative references 3 3 Definition 3 4 Hazard classes 3 5 Durability classes 3 6 Durability for use in the various hazard classes 3 Anne
21、x A (informative) Important factors intherelationship between expected servicelifeandnatural durability 5 Annex B (informative) Hazard classes andgeneralservice situations taken from Table1ofEN 335-1 6 Annex C (informative) Bibliography 6 Table 1 Wood-destroying fungi Guidance onthe durability class
22、es of wood species for use inhazard classes 4 Table B.1 General service situations and hazardclasses given in EN335-1 (extract ofTable1of EN335-1) 6EN460:1994 BSI 07-1999 3 Introduction Where wood-destroying organisms are likely to attack timber in service, either a timber of sufficient natural dura
23、bility should be selected or the durability characteristics of the timber should be enhanced by preservative treatment. Guidance on the various classification systems used to describe the natural durability of timber to attack by wood-destroying organisms is given in EN350-1, and the system used to
24、classify preservative-treated timber is given in EN351-1. The need for specific durability characteristics for a timber will depend on its conditions of service (as defined by the class of biological hazard, see EN335-1 and EN335-2). 1 Scope This European Standard gives guidance on the selection of
25、wood species based on their natural durability to attack by wood-destroying organisms for use as solid wood or as glued laminated timber (glulam) in the hazard classes defined in EN335-1. This standard does not consider the durability characteristics of the glue used in glued laminated timber. 2 Nor
26、mative references This European Standard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions
27、of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies. EN 335-1:1992, Durability of wood and wood-based products Definitions of hazard classes of biological
28、attack Part 1: General. EN 335-2:1992, Durability of wood and wood-based products Definitions of hazard classes of biological attack Part 2: Application to solid wood. EN 350-2:1994, Durability of wood and wood-based products Natural durability of solid wood Part2: Guide to natural durability and tr
29、eatability of selected wood species of importance in Europe. 3 Definition For the purposes of this standard, the following definition applies. 3.1 glued laminated timber structural member formed by bonding together timber laminations with the grain running essentially parallel 4 Hazard classes The s
30、ervice situations in which wood is susceptible to biological attack have been divided into five hazard classes which are defined in EN335-1 (seeTable B.1). Guidance on the application of these hazard classes to solid wood is given in EN335-2. 5 Durability classes Classification systems for the natur
31、al durability of solid wood based on resistance to attack by various wood-destroying organisms are given in EN350-1. 6 Durability for use in the various hazard classes 6.1 General The natural durability of a wood species should be considered separately for each wood-destroying organism. In practice
32、supplies of sawn timber may include sapwood as well as heartwood. If the proportion of sapwood present is such that its loss would have adverse implications for the performance of the component, or if the sapwood and heartwood cannot be distinguished, the durability of the whole component should be
33、regarded as equivalent to that of the sapwood. In addition to the natural durability, there are other factors that influence performance which should also be taken into consideration in the selection of a wood species and the decision whether or not it should be treated with a preservative.EN460:199
34、4 4 BSI 07-1999 For example wood with low permeability may acquire lower moisture contents under intermittent wetting conditions, compared to more permeable species, and will therefore have a reduced risk of fungal attack under such service conditions. An indication of propensity to take up moisture
35、 may be obtained from the treatability classification of different wood species (see EN350-2). Hence timbers having a particular natural durability classification for wood-destroying fungi and with a treatability classification of3 or4 may achieve an increased service life in out of ground contact c
36、onditions (hazard class2 or hazard class3) compared to wood of similar durability classification but with a treatability classification of 1or2. Information on some further factors is given in Annex A. 6.2 Natural durability to wood-destroying fungi Guidance on the use of a wood species in the vario
37、us hazard classes depending upon their degree of natural durability is given in Table 1. If the natural durability is inadequate, preservative treatment should be considered. Table 1 Wood-destroying fungi Guidance on the durability classes of wood species for use in hazard classes 6.3 Natural durabi
38、lity to wood-destroying beetles Wood-destroying beetles are present throughout the European area, but the risk of attack varies greatly from high to insignificant. Reference should be made to local or regional expertise for advice on the risk of attack by wood-destroying beetles. In situations where
39、 there is a significant risk of attack which would result in an unacceptable loss of strength or visual degradation, wood species classified as susceptible in EN350-2 should be treated with a preservative. 6.4 Natural durability to termites In situations where there is a significant risk of termite
40、attack only the heartwood of wood species which is classified in EN350-2 as “durable” (D) or “moderately durable” (M) to termites may be used untreated. The choice between “durable” (D) and “moderately durable” (M) wood depends upon the specific requirements, for example for function, end use, expec
41、ted service life, and the significance of failure. 6.5 Natural durability to marine organisms In situations where there is a significant risk of attack by marine organisms, only the heartwood of wood species which is classified in EN350-2 as “durable” (D) or “moderately durable” (M) to marine organi
42、sms may be used untreated. The choice between “durable” (D) and “moderately durable” (M) wood depends upon the specific requirements, for example for function, end use, expected service life, and the significance of failure. Hazard class Durability class 1 2 3 4 5 1 o o o o o 2 o o o (o) (o) 3 o o (
43、o) (o) (x) (o) (x) 4 o (o) (x) x x 5 o (x) (x) x x Key o natural durability sufficient. (o) natural durability is normally sufficient, but for certain end uses treatment may be advisable (seeAnnex A). (o) (x) natural durability may be sufficient, but depending on the wood species, its permeability (
44、see6.1), and end use (seeAnnex A), preservative treatment may be necessary. (x) preservative treatment is normally advisable, but for certain end uses natural durability may be sufficient (seeAnnex A). x preservative treatment necessary. NOTESapwood of all wood species should be regarded as durabili
45、ty class5.EN460:1994 BSI 07-1999 5 Annex A (informative) Important factors in the relationship between expected service life and natural durability A.1 Service life The service life of a timber component will depend upon many factors, not just durability classification against wood-destroying organi
46、sms. For instance, in hazard class3 the design details of a timber component, which prevent water penetration and collection and encourage drainage and ventilation, together with local climatic conditions and maintenance procedures, may have an influence on long-term performance. Similarly, in hazar
47、d class 4 climatic conditions can have a marked effect on performance. Therefore, it is not appropriate to base an expected service life solely upon the durability classification. For most constructional uses there is a generally accepted minimum level of natural durability, which in conjunction wit
48、h the other factors gives a service life considered reasonable for a given component. The selection of a wood with a higher durability classification than that recommended in this standard may be expected to provide an increased service life for a given end-use. If constructional components are requ
49、ired to have only a short service life (temporary or semi permanent) or if extreme longevity is necessary, it may be appropriate to use wood species with lower or higher durability classifications than those given in Table 1. An estimate of expected service life may be obtained by comparing the durability of the wood which is proposed for use with the known durability and service life of other well known wood species that have been used in the same location and for constructions with similar design and mai
