1、CEN ENa460 94 = 3404589 0065290 OT8 = BRITISH STANDARD Durability of wood and wood-based products - Natural durability of solid 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 Durabilit du bois et des
2、 matriaux drivs du bois - Durabilite naturelle du bois massif - Guide dexigences 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
3、fr die Anwendung in den Gefhrdungsklassen UDC 674.03. 620.193.8 : 620.193.91 BS EN 460 : 1994 CEN EN*460 94 m 3404589 0065293 T34 m under the authority of the effect on 15 August 1994 0 BSI 1994 Standards Board and comes into Amd. No. The following BSI references relate to the work on this standard:
4、 Committee reference B/515 Draft for comment 91161885 DC ISBN O 580 22911 4 BSEN460: 1994 Date Rxt affected Cooperating organizations The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the f
5、ollowing countries: Austria Belgium Denmark Finland France Germany Greece Iceland Ireland Italy Luxembourg Netherlands Norway Portugal Spain Sweden Switzerland United Kingdom Oesterreichisches Normungsinstitut Institut belge de normalisation Dansk Standard Suomen Standardisoimisliito, r. y. Associat
6、ion franaise de normalisation Deutsches Institut fr Normung e.V. Hellenic Organization for Standardization Tkchnological Institute of Iceland National Standards Authority of Ireland Ente Nazionale Italiano di Unificazione Inspection du Travail et des Mines Nederlands Normalisatie-instituut Norges St
7、andardiseringsforbund Instituto Portugus da Qualidade Asociacin Espaola de Normalizacin y Certificacin Standardiseringskommissionen i Sverige Association suisse de normalisation British Standards Institution CEN EN*4bO 9q D 3404589 O065292 970 D BS EN 460 : 1994 Contents Cooperating organizations Na
8、tional foreword page Inside front cover i Foreword 2 kxt of EN 460 3 National annex NA (informative) Committees responsible Inside back cover National annex NB (informative) Cross-references Inside back cover National foreword This British Standard has been prepared under the direction of the Techni
9、cal Sector Board for Building and Civil Engineering and is the English language version of 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, published by the European Committee f
10、or Standardization (CEN). EN 460 was produced as a result of international discussion in which the United Kingdom took an active part. Compliance with a British Standard does not of itself confer immunity from legal obligations. i CEN EN*4b 74 m 3404589 0065273 807 m EUROPEAN STANDARD EN 460 NORME E
11、UROPENNE EUROPISCHE NORM May 1994 UDC 674.03 : 620.193.8 : 620.193.91 Descriptors: Wood, tests, durability, classifications, biodegradability, hazards, pest resistance English version Durability of wood and wood-based products - Natural durability of solid wood - Guide to the durability requirements
12、 for wood to be used in hazard classes Durabilit du bois et des matriaux drivs du bois - Durabilit naturelle du bois massif - Guide dexigences de durabilit du bois pour son utilisation selon les classes de risque Dauerhaftigkeit von Holz und Holzprodukten - Natrliche Dauerhaftigkeit von Vollholz - L
13、eitfaden fr die Anforderungen an die Dauerhaftigkeit von Holz fr die Anwendung in den Gefhrdungsklassen This European Standard was approved by CEN on 1994-05-18. CEN members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard
14、the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (Enghsh, French, Germa
15、n). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Ge
16、rmany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36. 3-1050 Brussels O 1994 C
17、opyright reserved to CEN members Ref. No. EN 460 : 1994 E CEN EN+4b0 94 m 3404589 0065294 743 m Page 2 EN460: 1994 Foreword This European Standard has been drawn up by WG 2 Natural durability of Qchnical Committee CEN/TC 38, Durability of wood and wood-based products, with AFNOR as Secretariat. This
18、 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 November 1994, and conflicting national standards shall be withdrawn at the latest by December 1996. This European Standard was adopted by CEN and in a
19、ccordance with the Common CENKENELEC Rules, the following countries are bound to implement this European Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. Introduct
20、ion Where wood-destroying organisms are likely to attack timber in service, either a timber of sufficient natural durability should be selected or the durability characteristics of the timber should be enhanced by preservative treatment. Guidance on the various classification systems used to describ
21、e the natural durability of timber to attack by wood-destroying organisms is given in EN 350-1, and the system used to classify preservative-treated timber is given in EN 351-1. The need for specific durability characteristics for a timber will depend on its conditions of service (as defined by the
22、class of biological hazard, see EN 335-1 and EN 335-2). Contents Foreword Introduction 1 Scope 2 Normative references 3 Definition 4 Hazard classes 5 Durability classes 6 Durability for use in t,he various hazard classes Annex A (informative) Important factors in the relationship between expected se
23、rvice life and natural durability Annex B (informative) Hazard classes and general service situations taken from table 1 of EN 335-1 Annex C (informative) Bibliography Page 3 5 5 6 CEN EN*YbO 9Y D 3404589 00b5295 b8T 1 Scope This European Standard gives guidance on the selection of wood species base
24、d 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 EN 335-1. This standard does not consider the durability characteristics of the glue used in glued laminated timber. 2 Normative reference
25、s 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 of any of these
26、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 attack - Part
27、 1: General Durability of wood and wood-based products - Definitions of hard classes of biological attack - Part 2: Application to solid wood Durability of wood and wood-based products - Natural durability of solid wood - Part 2: Guide to natural durability and treatability of selected wood species
28、of importance in Europe EN 335-2 : 1992 EN 350-2 : 1994 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 servi
29、ce situations in which wood is susceptible to biological attack have been divided into five hazard classes which are defined in EN 335-1 (see table B.l). Guidance on the application of these hazard classes to solid wood is given in EN 335-2. Page 3 EN 460 : 1994 5 Durability classes Classification s
30、ystems for the natural durability of solid wood based on resistance to attack by various wood-destroying organisms are given in EN 350- 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
31、organism. In practice 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 whol
32、e component should be 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
33、preservative. 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 m
34、ay be obtained from the treatability classification of different wood species (see EN 350-2). Hence timbers having a particular natural durability classification for wood-destroying fungi and with a treatability classification of 3 or 4 may achieve an increased service life in out of ground contact
35、conditions (hazard class 2 or hazard class 3) compared to wood of similar durability classification but with a treatability classification of 1 or 2. 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
36、various 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. CEN EN*4b0 94 3404589 0065296 5Lb Page 4 EN 460 : 1994 able 1. Wood-destroying fungi - Guidance on the durability classe
37、s of wood species for use in hazard classes class I l l I I 2 lo /o lo /(o) l(o) Key o natural durability sufficient. (0) natural durability is normally sufficient, but for certain end uses treatment may be advisable (see annex A). natural durabiljty may be sufficient, but depending on the wood spec
38、ies, its permeability (see 6.1), and end use (see annex A), preservative treatment may be necessary. advisable, but for certain end uses natural durability may be sufficient (see annex A). (o) - (x) (XI preservative treatment is normally X preservative treatment necessary NOTE. Sapwood of all wood s
39、pecies should be regarded as durability class 5. 6.3 Natural durability 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
40、 the risk of attack by wood-destroying beetles. In situations where 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 EN 350-2 should be treated with a preservative. 6.4 Natural durability to
41、termites In situations where there is a significant risk of termite attack only the heartwood of wood species which is classified in EN 350-2 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 sp
42、ecific requirements, for example for funct,ion, end use, expected 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 EN 350
43、-2 as durable (D) or moderately durable (M) to marine organisms 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. CEN EN*4b0 94 W 340
44、4589 00b5297 452 W Annex A (informative) Important factors in the relationship between expected service life and natural durability A.l Service life The service life of a timber component will depend upon many factors, not just durability classification against wood-destroying organisms. For instanc
45、e, in hazard class 3 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 hazard class 4 clima
46、tic 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 with the other fac
47、tors 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 required to have on
48、ly 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 w
49、ood 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 maintenance details. Where fungal attack occurs on lateral surfaces, the service life of a timber component can be expected to increase in proportion to its thickness. For example, a stake of cross-section 50 mm x 50 mm, embedded in the ground can be expected to have a service life approximately twice that of a stake of the same durability classi
