1、BRITISH STANDARDBS EN14257:2006Adhesives Wood adhesives Determination of tensile strength of lap joints at elevated temperature (WATT 91)The European Standard EN 14257:2006 has the status of a British StandardICS 83.180g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g
2、54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 14257:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June 2006 BSI 2006ISBN 0 580 48871 3National forewordThi
3、s British Standard is the official English language version of EN 14257:2006. The UK participation in its preparation was entrusted to Technical Committee PRI/52, Adhesives, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secre
4、tary.Cross-referencesThe 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 the BSI Electronic Catalogu
5、e 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 enquirers to understand the t
6、ext; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate them in the UK.Summary of pagesThis document comprises a front cover,
7、an inside front cover, the EN title page, pages 2 to 6, an inside back cover and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 142
8、57June 2006ICS 83.180English VersionAdhesives - Wood adhesives - Determination of tensile strengthof lap joints at elevated temperature (WATT 91)Adhsifs - Adhsifs pour bois - Dtermination de larsistance en traction temprature leve des joints recouvrement (essai WATT 91)Klebstoffe - Holzklebstoffe -
9、Bestimmung der Klebfestigkeitvon Lngsklebungen im Zugversuch in der Wrme (WATT91)This European Standard was approved by CEN on 21 November 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a na
10、tional standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards 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 an
11、y other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland,
12、 France,Germany, 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
13、 NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 14257:2006: EEN 14257:2006 (E) 2 Contents Page Foreword3 1 Scope.4 2 Normative references 4 3 Terms and definitions4
14、4 Principle 4 5 Apparatus .4 6 Sample preparation5 6.1 Preparation of the bonded test pieces.5 6.2 Conditioning bonded assemblies or test pieces 5 7 Test procedure .5 8 Calculation and expression of results.5 9 Test report 5 9.1 General5 9.2 The adhesive 6 9.3 Preparation of the test pieces and test
15、ing procedures6 9.4 Test results .6 EN 14257:2006(E) 3 Foreword This European Standard (EN 14257:2006) 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 standard, either by public
16、ation of an identical text or by endorsement, at the latest by December 2006, and conflicting national standards shall be withdrawn at the latest by December 2006. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implemen
17、t this European Standard: Austria, Belgium, 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, Sweden, Switzerland and United Ki
18、ngdom. EN 14257:2006 (E) 4 SAFETY STATEMENT: Persons using this European Standard should be familiar with the normal laboratory practice, in principle. This European Standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user
19、 to establish appropriate safety and health practices and to ensure compliance with any regulatory conditions. 1 Scope This European Standard specifies a method for testing the strength of wood adhesives at 80 C. NOTE The procedure described is based on a test developed in Germany known originally a
20、s the WATT 91 test. It uses the test piece described in EN 205. 2 Normative references The following referenced documents are indispensable for the application of this European Standard. For dated references, only the edition cited applies. For undated references, the latest edition of the reference
21、d document (including any amendments) applies. EN 205, Adhesives Wood adhesives for non-structural applications Determination of tensile shear strength of lap joints EN 923, Adhesives Terms and definitions ISO 5893, Rubber and plastics test equipment Tensile, flexural and compression types (constant
22、 rate of traverse) Specification 3 Terms and definitions For the purposes of this European Standard, the terms and definitions given in EN 923 apply. 4 Principle A symmetrical bonded lap joint between two wooden adherents is subjected to a period of heating at controlled temperature and then straine
23、d to rupture by a longitudinal force parallel to the grain. The heating test is normally carried out on thin (0,1 mm) glue lines. However if the manufacturer makes specific claims for the gap filling properties of the test adhesive then the heating test is carried out with both thin and thick (1 mm)
24、 glue lines. 5 Apparatus 5.1 Tensile testing machine, as described in ISO 5893, capable of maintaining a constant strain rate of 50 mm/min. The jaws shall be mounted in such a way as to permit self-alignment whilst the test pieces are being pulled. 5.2 Fan assisted oven, capable of maintaining a tem
25、perature of (80 2) C. EN 14257:2006(E) 5 6 Sample preparation 6.1 Preparation of the bonded test pieces Prepare 10 test pieces in accordance with the procedure described in EN 205. 6.2 Conditioning bonded assemblies or test pieces After bonding and pressing, condition the assembly or test pieces for
26、 a minimum of seven days in a standard atmosphere of either (20 2) C, (65 5) % relative humidity 20/65 or (23 2) C, (50 5) % relative humidity 23/50. 7 Test procedure Place each test piece, in a preheated fan oven, at (80 2) C, for (60 2) min and then test it to fracture in a tensile testing machine
27、. NOTE In order to allow time for removal and testing it can be helpful to place the test pieces into the oven at set intervals, and to remove them in sequence after each has been in the oven for 1 h. Whilst in the oven, the test pieces shall be well spaced in the circulating air. The time between r
28、emoval of the test piece from the oven and the start of the test (beginning of the application of the load) shall be (9 1) s. Clamp the ends of the test pieces in the jaws of the tensile testing machine to a length of 40 mm to 50 mm. Load the test piece to fracture and determine the maximum force Fm
29、ax. The rate of separation of the jaws shall be 50 mm/min. 8 Calculation and expression of results Calculate the hot strength, , of the joint in N/mm2using the equation: maxFA = where Fmaxis maximum force in Newtons; A is area of bonded test surface in square millimetres. 9 Test report 9.1 General A
30、 reference to this European Standard, i.e. EN 14257 and the items listed in 9.2 to 9.4 shall be recorded in the test report. EN 14257:2006 (E) 6 9.2 The adhesive a) Type and origin of the adhesive; b) batch number or other marking of uniquely identifying the adhesive used; c) number of components an
31、d working methods (procedure of preparing and applying of adhesive); d) durability class (for information only). 9.3 Preparation of the test pieces and testing procedures a) Species of wood with botanical name; b) moisture content of wood relative to oven-dry mass; c) characteristic data relating to
32、 the bonding procedure (for instance information about the amount of glue applied, the open and closed assembly time, pressing pressure, pressing temperature, pressing time); d) special treatment of the surface of the boards to be bonded; e) time between the termination of pressing and the cutting o
33、f the test pieces; f) indication whether test pieces with a thin (0,1 mm) bond-line or with a thick (1 mm) bond-line have been used; g) number of bonded test pieces; h) conditioning atmosphere used; i) rate of traverse or the time required to rupture. 9.4 Test results a) Hot strength in Newton per s
34、quare millimetre, rounded to nearest 0,1 N/mm2of each of the 10 test pieces; b) mean and standard deviation of the 10 values of hot strength and coefficient of variation (expressed as percentage); c) for each test piece, an indication of the proportion of wood failure graded as follows: 0 %, 25 %, 5
35、0 %, 75 %, 100 % and mean percentage wood failure for the group of 10 test pieces; d) any further particularities in the appearance of the bounded surfaces; e) any deviation from this European Standard; f) date of test and details of the testing organisation. blankBS EN 14257:2006BSI389 Chiswick Hig
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