1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 302-7:2013Adhesives for load-bearing timber structures T e s t m e t h o d sPart 7: Determination of the working life under referenced conditionsBS EN 302-7:2013 BRITISH ST
2、ANDARDNational forewordThis British Standard is the UK implementation of EN 302-7:2013. It supersedes BS EN 302-7:2004, which is withdrawn.The UK participation in its preparation was entrusted to T e c h n i c a l C o m m i t t e e P R I / 5 2 , A d h e s i v e s .A list of organizations represented
3、 on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2013. Published by BSI Standards Limited 2013.ISBN 978 0 580 75
4、260 5 ICS 83.180 Compliance with a British Standard cannot confer immunityfrom 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 T e x t a f f e c t e dBS EN 302-7:2013EURO
5、PEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 302-7 March 2013 ICS 83.180 Supersedes EN 302-7:2004English Version Adhesives for load-bearing timber structures - Test methods - Part 7: Determination of the working life under referenced conditions Adhsifs pour structures portantes en bois - Mthodes
6、 dessai - Partie 7 : Dtermination de la dure dutilisation dans des conditions de rfrence Klebstoffe fr tragende Holzbauteile - Prfverfahren - Teil 7: Bestimmung der Gebrauchsdauer bei Referenzbedingungen This European Standard was approved by CEN on 5 February 2013. CEN members are bound to comply w
7、ith 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 CEN-CENELEC Man
8、agement 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 has the same s
9、tatus 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, Luxembourg, Ma
10、lta, 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 CEN All right
11、s of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 302-7:2013: EBS EN 302-7:2013EN 302-7:2013 (E) 2 Contents Page Foreword 3 Introduction .4 1 Scope 6 2 Normative references 6 3 Terms and definitions .6 4 Principle 6 5 Apparatus .6 6 Procedure .7
12、7 Expression of results 8 8 Test report 8 BS EN 302-7:2013EN 302-7:2013 (E) 3 Foreword This document (EN 302-7:2013) 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, ei
13、ther 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. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CE
14、N and/or CENELEC shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 302-7:2004. According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Aust
15、ria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Swede
16、n, Switzerland, Turkey and the United Kingdom. BS EN 302-7:2013EN 302-7:2013 (E) 4 Introduction This document is one of a series dealing with adhesives for use with timber structures, and is published in support of EN 1995, Eurocode 5: Design of timber structures. The series consists of three classi
17、fication and performance requirements for adhesives for load-bearing timber structures; phenolic and aminoplastic adhesives (EN 301), one component polyurethane adhesive (EN 15425) and emulsion polymerised isocyanate adhesive (prEN 16254) and all together eleven test methods (EN 302 Parts 1 to 7 and
18、 EN 15416 Parts 2 to 5). These European Standards have the following titles: EN 301, Adhesives, phenolic and aminoplastic, for load-bearing timber structures Classification and performance requirements EN 15425, Adhesives One component polyurethane for load bearing timber structures Classification a
19、nd performance requirements prEN 16254, Adhesives Emulsion polymerized isocyanate (EPI) for load-bearing timber structures Classification and performance requirements EN 302, Adhesives for load-bearing timber structures Test methods Part 1: Determination of longitudinal tensile shear strength Part 2
20、: Determination of resistance to delamination Part 3: Determination of the effect of acid damage to wood fibres by temperature and humidity cycling on the transverse tensile strength Part 4: Determination of the effects of wood shrinkage on the shear strength Part 5: Determination of maximum assembl
21、y time under referenced conditions Part 6: Determination of the minimum pressing time under referenced conditions Part 7: Determination of the working life under referenced conditions EN 15416, Adhesives for load bearing timber structures other than phenolic and aminoplastic Test methods Part 2: Sta
22、tic load test of multiple bondline specimens in compression shear Part 3: Creep deformation test at cyclic climate conditions with specimens loaded in bending shear Part 4: Determination of open assembly time for one component polyurethane adhesives Part 5: Determination of conventional pressing tim
23、e Safety statement Persons using this document should be familiar with the normal laboratory practice, if applicable. This document cannot address all of the safety problems, if any, associated with its use. It is the responsibility of the user to establish appropriate safety and health practices an
24、d to ensure compliance with any regulatory conditions. BS EN 302-7:2013EN 302-7:2013 (E) 5 Environmental statement It is understood that some of the material permitted in this standard can have a negative environmental impact. As technological advantages lead to better alternatives for these materia
25、ls, they will be eliminated from this standard to the greatest extent possible. At the end of the test, it is recommended that the user of the standard take care to carry out an appropriate disposal of the wastes, according to local regulations. BS EN 302-7:2013EN 302-7:2013 (E) 6 1 Scope This Europ
26、ean Standard specifies a method for determining the working life for adhesives mixed with hardener for load-bearing timber structures, by a viscosity test. This method is not suitable for determining the working life of a multi-component adhesive whose actual working life is very short. This documen
27、t is only intended for obtaining a reliable basis for comparison between adhesives. The method gives results which cannot be applied to the safe manufacture of timber structures without modifications for the influences of factory temperature and relative air humidity. 2 Normative references The foll
28、owing documents, in whole or in part, are normatively referenced in this document and are indispensable 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 923:2005+A1:
29、2008, Adhesives Terms and definitions EN ISO 2555:1999, Plastics Resins in the liquid state or as emulsions or dispersions Determination of apparent viscosity by the Brookfield test method (ISO 2555:1989) 3 Terms and definitions For the purposes of this document, the terms and definitions given in E
30、N 923:2005+A1:2008 and the following apply. 3.1 working life under referenced conditions period of time at 20 C during which an adhesive, prepared for application, increases in apparent viscosity to 25 000 mPa s under referenced conditions 4 Principle The viscosity of a specified volume of adhesive
31、at 20 C is monitored using a Brookfield type viscometer, until it reaches 25 000 mPa s. 5 Apparatus 5.1 Beaker, approximately 850 ml capacity, 90 mm to 95 mm internal diameter, 115 mm to 160 mm height with a wall thickness not exceeding 1 mm. The beaker shall be made of a material that ensures a goo
32、d heat conductivity and that does not react with the adhesive. NOTE A stainless steel beaker is suitable for most of the commercial adhesives used for the gluing of load-bearing timber structures. 5.2 Brookfield type viscometer, type A. BS EN 302-7:2013EN 302-7:2013 (E) 7 The detailed operating prin
33、ciple of this apparatus, its description and characteristics are given in EN ISO 2555. The viscometer comprises the following elements: the viscometer body; seven removable, interchangeable spindles, numbered 1 to 7; a support which holds the viscometer and moves it into the vertical plane; a remova
34、ble guard stirrup, which is not used in this method. NOTE A Brookfield RVF model is an example of a suitable product available commercially.1)5.3 Temperature regulated water bath, capable of maintaining the mixture to be tested at 20 C with an accuracy of 2 C. 5.4 Thermometer, graduated to 0,1 C, to
35、 measure the temperature of the adhesive being tested. 6 Procedure 6.1 Handle the adhesive components in accordance with the instructions of the manufacturer of the adhesive. Ensure that at the start of the test, all the components have a temperature of (20 0,5) C. Ensure that during the test, the r
36、elative humidity of the air in the testing room remains at (65 5) %. NOTE It is a common practice to store the components at (20 2) C for one night before testing. 6.2 Set up, calibrate and operate the viscometer in accordance with the instructions of the instrument manufacturer. Choose a rotational
37、 frequency of 20 min-1. Spindles shall be chosen such that the instrument reading is in the range from 20 % to 95 % of the full scale value. 6.3 Prepare a sufficient amount of the glue mix in the beaker (5.1) to fill 2/3 of its volume, in accordance with the specifications of the manufacturer. Start
38、 to record the time at the moment (t0) the component that initiates the reaction is added. 6.4 Gently stir the mixture manually for 5 min at (20 2) C. In order to allow any exothermic reaction to proceed normally, do not place the beaker in the water bath during this operation and avoid heating the
39、mixture by body heat through the hand. 6.5 Place the beaker in the water bath (5.3) adjusted at (20 2) C for the rest of the procedure. Adjust the water level of the water bath so that it is slightly above that of the adhesive in the beaker (5.1). Keep the beaker uncovered throughout the test. 6.6 D
40、etermine the viscosity of the adhesive system at 15 min intervals, or with shorter intervals for fast setting adhesives, from the initial time (t0). About one minute before each reading, gently stir the sample for 15 s to ensure homogeneity. 6.7 Remove the beaker from the water bath, hold the spindl
41、e at an angle of about 45 to the surface of the adhesive and immerse it in the product, taking care not to introduce air bubbles. Orientate the spindle vertically and connect it to the shaft of the apparatus. Check that the spindle is vertical using the bubble level and that the spindle is immersed
42、to the underside of the mark on its shaft. Allow the instrument to run for 30 s and read the torque meter to the nearest 0,25 % of the maximum value indication at the pre-set time. Lock the 1) This information is given for the convenience of users of this European Standard and does not constitute an
43、 endorsement by CEN of the product named. Equivalent products may be used if they can be shown to lead to the same results. BS EN 302-7:2013EN 302-7:2013 (E) 8 needle and stop the motor to take the reading. Immerse the thermometer (5.4) into the sample and record the temperature. Place the beaker ba
44、ck into the water bath (5.3). 6.8 After each measurement, detach the spindle from the instrument, wash it thoroughly in a suitable solvent and dry it before re-use. 6.9 Continue determining the viscosity of the sample at 15 min intervals until the viscosity exceeds 25 000 mPa s. In order to increase
45、 the accuracy of the determination of the conventional working life, it is advisable to reduce the time interval between two readings in the final stage of the reaction. 7 Expression of results Calculate the apparent viscosity, in millipascal seconds (mPa s), of the adhesive system tested, using the
46、 formula: = k x l where is viscosity in millipascal seconds; k is a coefficient depending on the rotational frequency-spindle combination used; in the case of apparatus as specified in 5.2 and in EN ISO 2555:1999, B.3, the values of k are as shown in Table 1; l is the value read on the scale. Table
47、1 Coefficient k (scale 0 to 100) for each spindle and a rotational frequency of 20 min-1 Spindle number 1 2 3 4 5 6 7 Coefficient k 5 20 50 100 200 500 2 000 Plot the change of apparent viscosity with time (in minutes). Record the working life of the adhesive under referenced conditions as the time
48、between t0(see 6.3) and the time that the apparent viscosity reaches 25 000 mPa s. 8 Test report The test report shall contain the following information: a) reference to this document (EN 302-7); b) identification of the adhesive system tested; c) proportions used when mixing the adhesive for use; d
49、) model of viscometer used; e) spindles used; BS EN 302-7:2013EN 302-7:2013 (E) 9 f) plotted curve giving the viscosity evolution in millipascal seconds, the time in minutes and, on the same graph, a second curve giving the evolution of the temperature during the test; g) value of the working life under referenced conditions; h) date of issue of the report; i) a note stressing the attention on the fact that the working life obtained by this standardized method is only relevant for comparison
