1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 335:2013Durability of wood and wood-based products Use classes: definitions, application to solid wood and wood-based productsBS EN 335:2013 BRITISH STANDARDNational forewo
2、rdThis British Standard is the UK implementation of EN 335:2013.It supersedes BS EN 335-1:2006 and BS EN 335-2:2006 andBS EN 335-3:1996 which are withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee B/515, Wood preservation.A list of organizations represented on this
3、 committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2013. Published by BSI Standards Limited 2013 ISBN 978 0 580 75630 6 ICS 7
4、1.100.50; 79.040 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2013.Amendments issued since publicationDate Text affectedBS EN 335:2013EUROPEAN STANDA
5、RD NORME EUROPENNE EUROPISCHE NORM EN 335 March 2013 ICS 71.100.50; 79.040 Supersedes EN 335-1:2006, EN 335-2:2006, EN 335-3:1995English Version Durability of wood and wood-based products - Use classes: definitions, application to solid wood and wood-based productsDurabilit du bois et des matriaux b
6、ase de bois - Classes demploi: dfinitions, application au bois massif et aux matriaux base de bois Dauerhaftigkeit von Holz und Holzprodukten - Gebrauchsklassen: Definitionen, Anwendung bei Vollholz und Holzprodukten This European Standard was approved by CEN on 5 February 2013. CEN members are boun
7、d 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 may be obtained on application to the CE
8、N-CENELEC Management Centre 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 CEN-CENELEC Management Centre h
9、as 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, L
10、uxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2013
11、CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 335:2013: EBS EN 335:2013EN 335:2013 (E) 2 Contents Page Foreword 3 Introduction .4 1 Scope 5 2 Normative references 5 3 Terms and definitions .5 4 Use classes: application to wood an
12、d wood-based products 5 4.1 General 5 4.2 Use class 1 (UC 1) 5 4.3 Use class 2 (UC 2) 6 4.4 Use class 3 (UC 3) 6 4.4.1 General 6 4.4.2 Sub-class 3.1 (UC 3.1) .6 4.4.3 Sub-class 3.2 (UC 3.2) .6 4.5 Use class 4 (UC 4) 6 4.6 Use class 5 (UC 5) 7 4.7 Summary of use classes for wood and wood-based produc
13、ts 8 Annex A (informative) Service classes according to EN 1995-1-1 9 Annex B (informative) Additional information for the assignment of use classes 10 Annex C (informative) Information on biological agents 11 C.1 General . 11 C.2 Fungi 11 C.2.1 General . 11 C.2.2 Wood-destroying fungi 11 C.2.3 Wood
14、-disfiguring fungi 11 C.3 Insects 12 C.3.1 Coleoptera (beetles) . 12 C.3.2 Isoptera (termites). 12 C.4 Marine borers 13 Bibliography . 14 BS EN 335:2013EN 335:2013 (E) 3 Foreword This document (EN 335:2013) has been prepared by Technical Committee CEN/TC 38 “Durability of wood and wood-based product
15、s”, the secretariat of which is held by AFNOR. 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 September 2013, and conflicting national standards shall be withdrawn at the latest by September 2013
16、. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 335-3:1995, EN 335-1:2006 and EN 335-2:2006. Compared to
17、 EN 335, parts 1 to 3, the main modifications are as follows: 1) the former three parts of EN 335 have been combined; 2) the subclasses 3.1 and 3.2 have been redefined; 3) the subdivision of use class 4 has been omitted. According to the CEN-CENELEC Internal Regulations, the national standards organ
18、isations of the following countries are bound to implement this European Standard: 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,
19、Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 335:2013EN 335:2013 (E) 4 Introduction This standard gives general definitions of use classes for different service situations and is relevant to solid wood and
20、 wood-based products. This standard gives information on the biological agents that can attack wood and wood-based products in defined situations. The possibility of alignment between the three service classes of Eurocode 5 (EN 1995-1-1) and the five use classes of EN 335 has been carefully studied.
21、 It is important to note that the two systems use different criteria to achieve different results. Annex A gives guidance on relationships between use classes and service classes. Annex B gives additional information for the assignment of use classes. Annex C gives information on biological agents.
22、BS EN 335:2013EN 335:2013 (E) 5 1 Scope This European Standard is applicable to solid wood and wood-based products. This European Standard defines five use classes that represent different service situations to which wood and wood-based products can be exposed. This standard also indicates the biolo
23、gical agents relevant to each situation. A use class is not a performance class and does not give guidance for how long wood and wood-based product will last in service. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispens
24、able for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 1001-2:2005, Durability of wood and wood-based products Terminology Part 2:Vocabulary EN 1995-1-1, Eurocode 5 D
25、esign of timber structures Part 1-1: General Common rules and rules for buildings 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 1001-2:2005 and the following apply. 3.1 service situation situation of exposure of the wood element in use 3.2 wood-base
26、d product any products containing wood Note 1 to entry: For instance solid wood panel, laminated veneer lumber (LVL), plywood, oriented strand board (OSB), resin-bonded particleboard, cement-bonded particleboard or fibreboard, modified wood are wood-based products. 4 Use classes: application to wood
27、 and wood-based products 4.1 General The differences between the use classes are based on differences in environment exposures that can make the wood or wood-based products susceptible to biological deterioration. NOTE Border line and extreme cases of use of wood and wood-based products exist. This
28、can cause the assignment of a use class that differs from that defined in this standard (see Annex B). 4.2 Use class 1 (UC 1) Situations in which the wood or wood-based product is inside a construction, not exposed to the weather and wetting. The attack by disfiguring fungi or wood-destroying fungi
29、is insignificant and always accidental. BS EN 335:2013EN 335:2013 (E) 6 Attack by wood-boring insects, including termites, is possible although the frequency and importance of the insect occurrence depends on the geographical region1). 4.3 Use class 2 (UC 2) Situations in which the wood or wood-base
30、d product is under cover and not exposed to the weather (particularly rain and driven rain) but where occasional, but not persistent, wetting can occur. In this use class, condensation of water on the surface of wood and wood-based products may occur. Attack by disfiguring fungi and wood-destroying
31、fungi is possible. Attack by wood-boring insects, including termites, is possible although the frequency and importance of the insect risk depends on the geographical region1). 4.4 Use class 3 (UC 3) 4.4.1 General Situations in which the wood or wood-based product is above ground and exposed to the
32、weather (particularly rain). Attack by disfiguring fungi and wood-destroying fungi is possible. Attack by wood-boring insects, including termites, is possible although the frequency and importance of the insect risk depends on the geographical region1). A large variety of in-use situations exists an
33、d, when relevant, use class 3 may be divided into two sub-classes use class 3.1 and use class 3.2. NOTE Decay risk depends on the climatic and other in-use conditions (temperature, RH, rainfall, structural conditions, design details and maintenance provisions). 4.4.2 Sub-class 3.1 (UC 3.1) In this s
34、ituation the wood and wood-based products will not remain wet for long periods. Water will not accumulate. NOTE This may be achieved by, for example, a maintained and suitable coating, or by design or orientation of components to shed water or to dry quickly. 4.4.3 Sub-class 3.2 (UC 3.2) In this sit
35、uation the wood and wood-based products will remain wet for long periods. Water may accumulate. NOTE Components are not designed or orientated to shed water or dry quickly. 4.5 Use class 4 (UC 4) A situation in which the wood or wood-based product is in direct contact with ground and/or fresh water.
36、 Attack by disfiguring fungi and wood-destroying fungi is possible. 1)If national standards do not specify the risk of insect attack, local or national experts should be consulted for advice on the risk of insect attack. BS EN 335:2013EN 335:2013 (E) 7 Attack by wood-boring insects, including termit
37、es, is possible although the frequency and importance of the insect occurrence depends on the geographical region 1). NOTE Wood and wood-based products which are constantly below water level or completely buried and fully saturated by water are not susceptible to be attacked by fungi but may be dama
38、ged by bacterial decay. 4.6 Use class 5 (UC 5) A situation in which the wood or wood-based product is permanently or regularly submerged in salt water (i.e. sea water and brackish water). Attack by invertebrate marine organisms is the principal problem, particularly in the warmer waters where organi
39、sms such as Limnoria spp., Teredo spp. and Pholads can cause significant damage. Attack by wood-destroying fungi and growth of surface moulds and staining fungi is also possible. The above water portion of certain components, for example harbour piles, can be exposed to wood-boring insects. BS EN 33
40、5:2013EN 335:2013 (E) 8 4.7 Summary of use classes for wood and wood-based products Table 1 Summary of use classes and relevant attacking biological agents for wood and wood-based products Use class General use situation aOccurrence of biological agents b, cDisfiguring fungi Wood-destroying fungiBee
41、tles Termites Marine borers 1 Interior, dry - - U L - 2 Interior, or under cover, not exposed to the weather. Possibility of water condensation U UU L - 3 Exterior, above ground, exposed to the weather. When sub-divided: 3.1 limited wetting conditions 3.2 prolonged wetting conditions U U U L - 4 Ext
42、erior in ground contact and/or fresh water U U U L - 5 Permanently or regularly submerged in salt water UdUdUdLdU U = ubiquitous in Europe and EU territories L = locally present in Europe and EU territories aBorder line and extreme cases of use of wood and wood-based products exist. This can cause t
43、he assignment of a use class that differs from that defined in this standard (see Annex B). bIt may not be necessary to protect against all biological agents listed as they may not be present or economically significant in all service conditions in all geographic regions, or may not be able to attac
44、k some wood-based products due to the specific constitution of the product. cSee Annex C. dThe above water portion of certain components can be exposed to all of the above biological agents.BS EN 335:2013EN 335:2013 (E) 9 Annex A (informative) Service classes according to EN 1995-1-1 EN 1995-1-1 def
45、ines a set of three service classes which are relevant to a designer when assigning strength values and calculating deformations for timber elements to be used in a construction. These service classes are determined by the wood moisture content corresponding to the humidity and temperature which are
46、 expected to prevail in service. The wood moisture content is also an important factor in biological durability, but the system of service classes in EN 1995-1-1 and the system of use classes in this standard differ in their considerations of the effects of this moisture, and individual classes do n
47、ot directly align with one another. Table A.1 gives guidance on the possible corresponding use classes for each of the service classes. Service class definitions in EN 1995-1-1 and use class definitions in this standard should be consulted to ensure correct classification. Attention of users is draw
48、n to the need to avoid misinterpretation of any numbering system using classes for timber that cannot correspond exactly to the European use classes defined in EN 335. Specifiers need to work with both systems when designing load bearing structures. Table A.1 Service classes and their possible corre
49、sponding use classes Service class according to EN 1995-1-1 Possible corresponding use class according to EN 335:2012 Service class 1 Use class 1 Service class 2 Use class 1 Use class 2 if the component is in a situation where it could be subjected to occasional wetting caused by e.g. condensation Service class 3 Use class 2 Use class 3 or higher if used externally BS EN 335:2013EN 335:2013 (E) 10 Annex B (informative) Additional information for the assignment of use classes If the use class or intended use conditions of a component cannot be accurately d
