1、BRITISH STANDARDBS EN 14256:2007Adhesives for non-structural wood applications Test method and requirements for resistance to static loadThe European Standard EN 14256:2007 has the status of a British StandardICS 83.180g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g
2、54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 14256:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 August 2007 BSI 2007ISBN 978 0 580 58716 0National forew
3、ordThis British Standard is the UK implementation of EN 14256:2007. The UK participation in its preparation was entrusted to Technical Committee PRI/52, Adhesives.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to in
4、clude all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 14256August
5、2007ICS 83.180English VersionAdhesives for non-structural wood applications - Test methodand requirements for resistance to static loadAdhsifs pour bois usages non structuraux - Mthodedessai et exigences pour la rsistance la charge statiqueHolzklebstoffe fr nicht tragende Anwendungen -Prfverfahren u
6、nd Anforderungen an die Bestndigkeitgegen statische BelastungThis European Standard was approved by CEN on 23 June 2007.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without
7、any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the CEN 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
8、by translationunder the responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Ge
9、rmany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGMa
10、nagement Centre: rue de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14256:2007: EEN 14256:2007 (E) 2 Contents Page Foreword3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Princi
11、ple4 5 Apparatus .5 6 Sample preparation .5 6.1 Preparation of test pieces.5 6.2 Conditioning bonded panels or test pieces7 7 Test procedure.7 8 Calculation and expression of results.7 9 Performance requirements .7 10 Test report 8 10.1 General8 10.2 The adhesive 8 10.3 Preparation of the test piece
12、s and the testing procedures.8 10.4 Test results.8 Bibliography 9 EN 14256:2007 (E) 3 Foreword This document (EN 14256:2007) has been prepared by Technical Committee CEN/TC 193 “Adhesives”, the secretariat of which is held by AENOR. This European Standard shall be given the status of a national stan
13、dard, either by publication of an identical text or by endorsement, at the latest by February 2008, and conflicting national standards shall be withdrawn at the latest by February 2008. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries
14、 are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, S
15、weden, Switzerland and United Kingdom. EN 14256:2007 (E) 4 Safety statement Persons using this document should be familiar with the normal laboratory practice, if applicable. This document does not purport to address all of the safety problems, if any, associated with its use. It is the responsibili
16、ty of the user to establish appropriate safety and health practices and to ensure compliance with any regulatory conditions. 1 Scope This European Standard specifies a method for determining the ability of a test piece bonded with a thermoplastic adhesive, to support a given load for a specified tim
17、e without fracture or excessive distortion, and specifies performance requirements for mean survival time. It should be used in conjunction with EN 204 and EN 205, which describe durability classes and corresponding test methods for non-structural wood adhesives based on their ability to withstand v
18、arious water treatments and relatively rapidly applied loads. The test described in this standard may be used to assess joints made with thin glue line, as defined in EN 205. NOTE The test described in this standard is not a mandatory requirement for the classification of adhesives into the classes
19、D1, D2, D3 and D4 given in EN 204. It is an additional test that can be specified by a purchaser if required. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references
20、, the latest edition of the referenced document (including any amendments) applies. EN 205:2003, Adhesives - Wood adhesives for non-structural applications - Determination of tensile shear strength of lap joints EN 923:2005, Adhesives -Terms and definitions EN 13183-1, Moisture content of a piece of
21、 sawn timber - Part 1: Determination by oven dry method EN 13183-2, Moisture content of a piece of sawn timber - Part 2: Estimation by electrical resistance method 3 Terms and definitions For the purposes of this document, the terms and definitions given in EN 923:2005 apply. 4 Principle A number of
22、 test pieces, each incorporating a symmetrical single lap joint between two rectangular wooden adherents, is placed in a jig in a climatically controlled environment. A weight is suspended from the jig applying a constant shear force to each joint for a period of 21 d. The time after which any joint
23、 fails is reported. EN 14256:2007 (E) 5 5 Apparatus 5.1 Jigs, for holding the test pieces (see Figure 1). 5.2 Weights, (30,0 0,5) kg with means of attachment to the jigs. 5.3 Enclosure, capable of maintaining the test piece assembly at (23 2) C and (50 5) % relative humidity. 6 Sample preparation 6.
24、1 Preparation of test pieces Prepare 10 test pieces, thin line only, in accordance with 7.1 to 7.2 of EN 205:2003 but with an overlap of (20,0 0,2) mm. A diagram of the test piece is given in Figure 1. EN 14256:2007 (E) 6 All dimensions in millimetres 0,5 unless otherwise stated Key 1 Plywood (5 to
25、7 ply) 2 Test piece The overlapping dimension l1is (20,0 0,2) mm Figure 1 Jig for assessing the resistance of bonded lap joints to a static load; hanging device made of 5 to 7-ply plywood Make flat-bottomed cuts of (2,5 0,5) mm width in the test pieces across the grain so that an overlap of (20,0 0,
26、2) mm is produced in the middle section, ensuring that cuts just cut through the bond-line but only penetrate as little as possible into the other part of the joint. EN 14256:2007 (E) 7 Apply the adhesive to be tested according to the manufacturer instructions. Where no manufacturer instructions are
27、 available for the application of the adhesive, use the following bonding procedures: The adhesive application shall be on both sides of the joint. The adhesive spread shall be (150 10) g/m2on each side. The open assembly time shall be (120 10) s. The closed assembly time shall be (180 10) s. The pr
28、essing pressure shall be 0,7 N/mm2 to 1,0 N/mm2. The pressing time shall be minimum of 2 h. 6.2 Conditioning bonded panels or test pieces After bonding and pressing, condition the bonded assemblies or test pieces for a minimum of seven days but not more than eight days in the standard atmosphere tha
29、t is to be used for testing, i.e. (23 2) C and (50 5) % relative humidity, 23/50. 7 Test procedure Just after the conditioning period described in 6.2, carry out the test at 23/50, testing 10 test pieces. Mount each test piece in the special jig (5.1) and suspend the jigs vertically. It is permissib
30、le to suspend one jig from another, up to a maximum of 10. Apply the required load of (30 0,5) kg to the bottom of the jig assembly. Failure is either when the test pieces are broken or when the two jigs are no longer supported by the specimen and they are in contact with each other because of the e
31、xtent of its deflection. Inspect the test pieces daily, and note the time to failure of each test piece, attributing a survival time, for example, of 3,5 d for test pieces failing between 3 d and 4 d, and 4,5 d for those failing between 4 d and 5 d, etc. Terminate the test after 21 d, or after a mea
32、n endurance of 14 d has been achieved, whichever is the sooner. Note the failure in days of each test piece. Standard deviation should be reported in test results. 8 Calculation and expression of results Calculate the mean survival time for the 10 test pieces and report the individual and mean survi
33、val times. 9 Performance requirements The mean survival time shall not be less than 14 d. EN 14256:2007 (E) 8 10 Test report 10.1 General The items listed in 10.2 to 10.4 shall be recorded in the test report. 10.2 The adhesive a) type and origin of the adhesive; b) batch number or other marking of u
34、niquely identifying the adhesive used; c) number of components and working methods (procedure of preparing and applying of adhesive); d) if known, durability class (for information only). 10.3 Preparation of the test pieces and the testing procedures a) species of wood with botanical name; b) moistu
35、re content of wood relative to oven-dry mass according to EN 13183-1, or the electric method according to EN 13183-2; c) characteristic data relating to the bonding procedure (for instance information about the amount of adhesive applied, the open and closed assembly time, pressing pressure, pressin
36、g temperature, pressing time); d) special treatment of the surface of the boards to be bonded (e.g. sanding); e) time between the termination of pressing and the cutting of the test pieces; f) number of bonded test pieces. 10.4 Test results a) indication that the test was carried out in accordance w
37、ith EN 14256; b) mean survival time and individual survival times of the test pieces; c) number of test pieces not failed (unbroken and still supporting the two jigs (see Clause 7) after 21 d loading; d) any deviations from this European Standard; e) date of test. EN 14256:2007 (E) 9 Bibliography 1
38、EN 204, Classification of thermoplastic wood adhesives for non-structural applications BS EN 14256:2007BSI389 Chiswick High RoadLondonW4 4ALBSI British Standards InstitutionBSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europ
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