1、BRITISH STANDARD BS EN 14374:2004 Timber structures Structural laminated veneer lumber Requirements The European Standard EN 14374:2004 has the status of a British Standard ICS 79.080; 91.080.20 BS EN 14374:2004 This British Standard was published under the authority of the Standards Policy and Stra
2、tegy Committee on 15 December 2004 BSI 15 December 2004 ISBN 0 580 45088 0 National foreword This British Standard is the official English language version of EN 14374:2004. EN 14374 is a candidate “harmonized” European Standard and fully takes into account the requirements of the European Commissio
3、n mandate M 112, “Structural timber products and ancillaries” given under the EU Construction Products Directive (89/106/EEC), and intended to lead to CE marking. The date of availability of EN 14374 as a harmonized European Standard, i.e. the date from which this standard may be used for CE marking
4、 purposes, is subject to an announcement in the Official Journal of the European Communities. The UK participation in its preparation was entrusted to Technical Committee B/518, Structural timber, which has the responsibility to: A list of organizations represented on this committee can be obtained
5、on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of th
6、e BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enq
7、uirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This do
8、cument comprises a front cover, an inside front cover, the EN title page, pages 2 to 23 and a back cover. The BSI copyright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPIS
9、CHENORM EN14374 November2004 ICS91.080.20;79.080 Englishversion TimberstructuresStructurallaminatedveneerlumber Requirements StructuresenboisLVL(Lamibois)Exigences HolzbauwerkeFurnierschichtholzfrtragendeZwecke Anforderungen ThisEuropeanStandardwasapprovedbyCENon22July2004. CENmembersareboundtocompl
10、ywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapplicationtotheCentralSecretariatortoanyCENmember. ThisEuropeanSt
11、andardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheCentralSecretariathasthesamestatusast heofficial versions. CENmembersarethenationalstandardsbodiesofAustria,Belgium,Cyprus,Czech
12、Republic,Denmark,Estonia,Finland,France, Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFORSTANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEF
13、RNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2004CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN14374:2004:EEN 14374:2004 (E) 2 Contents page Foreword3 1 Scope.4 2 Normative references.4 3 Terms, definitions and symbols .5 4 Requirements
14、5 4.1 Veneers .5 4.2 Bonding quality5 4.3 Dimensions and tolerances .6 4.4 Strength .6 4.4.1 General.6 4.4.2 Bending strength edgewise 6 4.4.3 Bending strength flatwise .6 4.4.4 Tension strength parallel to the grain .7 4.4.5 Tension strength perpendicular to the grain.7 4.4.6 Compression strength p
15、arallel to the grain.7 4.4.7 Compression strength perpendicular to the grain 7 4.4.8 Shear strength related to edgewise bending7 4.4.9 Shear strength related to flatwise bending.7 4.5 Stiffness.7 4.5.1 General.7 4.5.2 Modulus of elasticity parallel to the grain .7 4.5.3 Modulus of elasticity perpend
16、icular to the grain .8 4.5.4 Shear modulus related to edgewise bending .8 4.5.5 Shear modulus related to flatwise bending 8 4.6 Density.8 4.7 Moisture content 8 4.8 Reaction to fire 8 4.9 Release of formaldehyde 8 4.10 Natural durability against biological attack 8 5 Evaluation of conformity .8 5.1
17、General8 5.2 Initial type testing or assessment 9 5.2.1 General.9 5.2.2 Sampling.9 5.2.3 Characteristics to be initial type tested or assessed 9 5.3 Factory production control.11 5.3.1 General.11 5.3.2 Characteristics of the finished product to be control tested .11 6 Marking12 Z.1 Scope and relevan
18、t characteristics .17 Z.2 Procedure for attestation of conformity of laminated veneer lumber 18 Z.2.1 System of attestation of conformity18 Z.2.2 EC Certificate and Declaration of conformity.20 Z.3 CE Marking21 Bibliography 23 EN 14374:2004 (E) 3 Foreword This document (EN 14374:2004) has been prepa
19、red by Technical Committee CEN/TC 124 “Timber Structures“, the secretariat of which is held by SFS. 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 May 2005, and conflicting national standards sha
20、ll be withdrawn at the latest by May 2005. No existing European Standards are superseded. This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s). For relationship with EU
21、Directive(s), see informative annex ZA, which is an integral part of this document. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Est
22、onia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 14374:2004 (E) 4 1 Scope This document specifies the requirements for laminated
23、 veneer lumber for structural applications. The tests to be used, methods to carry out the evaluation of conformity and content of the marking of the product are given. This document does not cover laminated veneer lumber treated against biological attack or fire. 2 Normative references The followin
24、g referenced documents are indispensable for the application 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 314-1, Plywood Bonding quality Part 1: Test methods. EN 32
25、2, Wood-based panels Determination of moisture content. EN 323, Wood-based panels Determination of density. EN 350-2, Durability of wood and wood-based products Natural durability of solid wood Part 2: Guide to natural durability and treatability of selected wood species of importance in Europe. EN
26、408, Timber structures Structural timber and glued laminated timber Determination of some physical and mechanical properties. ENV 717-1, Wood-based panels Determination of formaldehyde release Part 1: Formaldehyde emission by the chamber method. EN 717-2, Wood-based panels Determination of formaldeh
27、yde release Part 2: Formaldehyde release by the gas analysis method. EN 789, Timber structures Test methods Determination of mechanical properties of wood based panels. EN 1438:1998, Symbols for timber and wood-based products. EN 13501-1, Fire classification of construction products and building ele
28、ments Part 1: Classification using test data from reaction to fire tests. prEN 14358, Structural timber Calculation of characteristic 5-percentile value. EN 14374:2004 (E) 5 3 Terms, definitions and symbols For the purposes of this document, the symbols in EN 1438:1998 and the following terms and de
29、finitions apply. 3.1 laminated veneer lumber (LVL) a composite of wood veneers with wood fibres essentially oriented in the same direction NOTE This definition does not exclude laminated veneer lumber with cross grained veneers. 3.2 characteristic strength and stiffness value the population fifth pe
30、rcentile value and for stiffness also the mean value obtained from results of tests with a duration of 300 s using test specimens at an equilibrium moisture content resulting from a temperature of 20 C and a relative humidity of 65 % 3.3 thickness the dimension of a cross section, which is perpendic
31、ular to the plane of the veneers, see Figure 1 3.4 width the dimension of a cross section, which is perpendicular to the thickness, see Figure 1 3.5 target size the size of the laminated veneer lumber member specified by the purchaser at the reference moisture content of (10 2) % a) b) t b t bFigure
32、 1 Thickness t and width b of cross section of laminated veneer lumber. Case a) is the cross section related to edgewise bending while case b) is the cross section related to flatwise bending 4 Requirements 4.1 Veneers The minimum number of veneers in the cross section shall be five. The maximum thi
33、ckness of each veneer shall be 6 mm. 4.2 Bonding quality The bonding quality shall be determined in accordance with the method given in annex B. For each tested glueline the apparent cohesive wood failure percentage shall be at least 70 %. EN 14374:2004 (E) 6 4.3 Dimensions and tolerances The thickn
34、ess shall not deviate more than +(0,8 + 0,03 t) mm or -(0,4 + 0,03 t) mm from the target thickness (t). NOTE Local thickness deviations related to discontinuities of the veneers, e.g. knot holes and veneer joints, are allowed. For widths 400 mm the width shall not deviate more than 2 mm from the tar
35、get width. For widths 400 mm the width shall not deviate more than 0,5 % from the target width. The length shall not deviate more than 5 mm from the target length. The angles of the cross section shall not deviate more than 1:50 (about 1,1) from a right angle, see Figure 2. Figure 2 Example of an an
36、gle of a cross section of laminated veneer lumber 4.4 Strength 4.4.1 General The manufacturer of laminated veneer lumber shall declare fifth percentile characteristic strength values. NOTE The orientation of strength is given in annex A. The characteristic values shall be determined from tests given
37、 in 4.4.2 to 4.4.9 and evaluated in accordance with the method given in prEN 14358. 4.4.2 Bending strength edgewise The bending strength tests shall be carried out in accordance with the test method given in EN 408. In edgewise bending the width of the specimen shall be at least 100 mm. If the width
38、 of the specimen is lower than the reference width of 300 mm, the individual test results shall be multiplied by the factor k m,corr:s corr m b k = 300 ,where b is the width of the tested specimen in mm and s is the size effect parameter given by: 05 , 0 2 = v s where v is the coefficient of variati
39、on of the test results. v may be taken less than 0,10 only if it is verified from at least two years of documented experience. 4.4.3 Bending strength flatwise The bending strength tests shall be carried out in accordance with the test method given in EN 408. In flatwise bending the thickness of the
40、specimen shall be at least 38 mm. EN 14374:2004 (E) 7 4.4.4 Tension strength parallel to the grain The tension strength tests parallel to the grain shall be carried out in accordance with the test method given in EN 408. The length of the specimen between the testing machine grips shall be at least
41、1 000 mm. If the length of the specimen between the testing machine grips is lower than the reference length of 3 000 mm, the individual test results shall be multiplied by the factor k t,corr:2 / , 000 3 s corr t l k = where l is the length of the specimen between the testing machine grips in mm an
42、d s is the size effect parameter given in 4.4.2. 4.4.5 Tension strength perpendicular to the grain The tension strength tests perpendicular to the grain shall be carried out in accordance with the test method given in EN 408. The cross section of the specimen shall be at least 45 mm x 45 mm. 4.4.6 C
43、ompression strength parallel to the grain The compression strength tests parallel to the grain shall be carried out in accordance with the test method given in EN 408. The cross section of the specimen shall be at least 45 mm x 45 mm. 4.4.7 Compression strength perpendicular to the grain The compres
44、sion strength tests perpendicular to the grain shall be carried out in accordance with the test method given in EN 408. The cross section of the specimen shall be at least 45 mm x 45 mm. 4.4.8 Shear strength related to edgewise bending The shear strength tests related to edgewise bending shall be ca
45、rried out in accordance with the test method given in EN 408. 4.4.9 Shear strength related to flatwise bending The shear strength tests related to flatwise bending shall be carried out in accordance with the planar shear test method given in EN 789. The thickness of the specimen shall be at least 25
46、 mm. 4.5 Stiffness 4.5.1 General The manufacturer of laminated veneer lumber shall declare fifth percentile as well as mean characteristic modulus of elasticity values and mean characteristic shear modulus values. The characteristic values shall be determined from tests given in 4.5.2 - 4.5.5 and ev
47、aluated in accordance with the method given in prEN 14358. 4.5.2 Modulus of elasticity parallel to the grain The modulus of elasticity tests parallel to the grain shall be carried out in accordance with the local modulus of elasticity in bending test method given in EN 408. The specimen shall be loa
48、ded in edgewise bending. The width of the specimen shall be at least 100 mm. EN 14374:2004 (E) 8 4.5.3 Modulus of elasticity perpendicular to the grain The modulus of elasticity tests perpendicular to the grain shall be carried out in accordance with the test method given in EN 408. The specimen shall be loaded in tension. The cross section of the specimen shall be at least 45 mm x 45 mm. 4.5.4 Shear modulus related to edgewise bending The shear modulus tests related to edgewise bending shall be carried
