BS EN 16254:2013+A1:2016 BS EN 16254:2013 BSI Standards Publication Adhesives — Emulsion polymerized isocyanate (EPI) for load-bearing timber structures — Classification and performance requirements BS EN 16254:2013+A1:2016 BRITISH STANDARD National foreword This British Standard is the UK implementation of EN 16254:2013+A1:2016 It supersedes BS EN 16254:2013 which is withdrawn The start and finish of text introduced or altered by amendment is indicated in the text by tags Tags indicating changes to CEN text carry the number of the CEN amendment For example, text altered by CEN amendment A1 is indicated by 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 include all the necessary provisions of a contract Users are responsible for its correct application © The British Standards Institution 2016 Published by BSI Standards Limited 2016 ISBN 978 580 91268 ICS 83.180 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 31 October 2013 Amendments/corrigenda issued since publication Date Text affected 30 April 2016 Implementation of CEN amendment A1:2016 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM ICS 83.180 EN 16254:2013+A1 April 2016 Supersedes EN 16254:2013 English Version Adhesives - Emulsion polymerized isocyanate (EPI) for load-bearing timber structures - Classification and performance requirements Adhésifs - Isocyanate polymérisé en émulsion (EPI) pour structures portantes en bois - Classification et exigences de performance Klebstoffe - Emulsionspolymerisiertes Isocyanat (EPI) für tragende Holzbauteile - Klassifizierung und Leistungsanforderungen This European Standard was approved by CEN on 22 June 2013 and includes Amendment approved by CEN on February 2016 CEN members are bound 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 CEN-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 has 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, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels © 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members Ref No EN 16254:2013+A1:2016 E BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Contents Page European foreword Introduction Scope Normative references Terms and definitions Classification 5.1 5.2 5.3 5.4 Requirements General Bond strength in longitudinal tensile shear test Resistance to delamination 10 Tensile strength perpendicular to the glue line after climatic treatment (acid damage test) 11 Effect of wood shrinkage on the shear strength 11 Static load test of multiple glue line specimens in compression shear 11 Creep deformation test at cyclic climate conditions with specimens loaded in bending shear 12 Long term sustained load test at cyclic climate conditions with specimens loaded perpendicular to the glue line (“Glass house test”) 12 5.5 5.6 5.7 5.8 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 7.1 7.2 7.3 7.4 Test methods 12 General 12 Determination of bond strength in longitudinal tensile shear test 12 Determination of resistance to delamination 12 Determination of tensile strength perpendicular to the glue line after climatic treatment (acid damaged test) 12 Determination of the effect of wood shrinkage on the shear strength 13 Static load test of multiple glue line specimens in compression shear 13 Creep deformation test with specimens loaded in bending shear 14 Long term sustained load test at cyclic climate conditions with specimens loaded perpendicular to the glue line (“Glass house test”) 14 Working properties of the adhesive 14 General 14 Determination of working life under reference conditions 14 Determination of open assembly time under reference conditions 14 Determination of pressing time under reference conditions 14 Annex A (normative) Climatic treatment prior to shear test 15 Annex B (normative) Glass house test 16 Annex C (informative) Product limitations and glulam production control for beams produced with Small Dimension adhesives 19 Bibliography 20 BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) European foreword This document (EN 16254:2013+A1:2016) 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 publication of an identical text or by endorsement, at the latest by October 2016, and conflicting national standards shall be withdrawn at the latest by October 2016 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 includes Amendment approved by CEN on 2016-02-09 This document supersedes EN 16254:2013 The start and finish of text introduced or altered by amendment is indicated in the text by tags !" According to the CEN/CENELEC Internal Regulations, the national standards organizations 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, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Introduction This document is one of a series dealing with emulsion polymerised isocyanate (EPI) adhesives for use with timber structures, and is published in support of product standards for bonded load-bearing timber structures The series consists of: — one standard for classification and performance requirements (EN 16254), — seven test methods (EN 302-1, EN 302-2, EN 302-3, EN 302-4, EN 15416-2, EN 15416-3 and the method given in Annex B of this standard (“Glass house”)) used to assess the performance of adhesives after specified heat and humidity treatments, and — three test methods (EN 302-7, EN 15416-4 and EN 15416-5) to characterise the working properties of the adhesive BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Scope This European Standard establishes a classification for emulsion polymerised isocyanate (EPI) adhesives according to their suitability for use in load-bearing timber structures in defined climatic exposure conditions, and specifies performance requirements for such adhesives for the industrial manufacture of load-bearing timber structures only !The performance requirements of this European Standard apply to the adhesives only, not to the timber structure This European Standard does not cover the performance of adhesives for on-site gluing (except for factory-like conditions) nor the production of wood-based panels, except solid wood panels, or modified and stabilized wood with considerably reduced swelling and shrinkage properties, e.g such as acetylated wood, heat treated wood and polymer impregnated wood." This European Standard is primarily intended for the use of adhesive manufacturers and for the use in timber structures bonded with adhesives, to assess or control the quality of adhesives This European Standard only specifies the performance of an adhesive for use in an environment corresponding to the defined conditions Such an adhesive meeting the requirements of this European Standard for its type is adequate for use in a load-bearing timber structure, provided that the bonding process has been carried out according to an appropriate product standard Normative references The following 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 302-1, Adhesives for load-bearing timber structures — Test methods — Part 1: Determination of longitudinal tensile shear strength EN 302-2, Adhesives for load-bearing timber structures — Test methods — Part 2: Determination of resistance to delamination EN 302-3, Adhesives for load-bearing timber structures — Test methods — Part 3: Determination of the effect of acid damage to wood fibres by temperature and humidity cycling on the transverse tensile strength EN 302-4, Adhesives for load-bearing timber structures — Test methods — Part 4: Determination of the effects of wood shrinkage on the shear strength EN 302-7, Adhesives for load-bearing timber structures — Test methods — Part 7: Determination of the working life under referenced conditions EN 923:2005+A1:2008, Adhesives — Terms and definitions EN 15416-2, Adhesives for load bearing timber structures other than phenolic and aminoplastic — Test methods — Part 2: Static load test of multiple bondline specimens in compression shear EN 15416-3, Adhesives for load bearing timber structures other than phenolic and aminoplastic — Test methods — Part 3: Creep deformation test at cyclic climate conditions with specimens loaded in bending shear BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) EN 15416-4, Adhesives for load bearing timber structures other than phenolic and aminoplastic — Test methods — Part 4: Determination of open assembly time for one component polyurethane adhesives EN 15416-5, Adhesives for load bearing timber structures other than phenolic and aminoplastic — Test methods — Part 5: Determination of conventional pressing time Terms and definitions For the purposes of this document, the terms and definitions given in EN 923:2005+A1:2008, and the following, apply 3.1 emulsion polymerised isocyanate (EPI) adhesive water based emulsion polymer or a mixture of water based emulsion polymers cross-linked with an isocyanate as hardener 3.2 service class climatic conditions characterised by a moisture content in the materials corresponding to a temperature of 20 °C and the relative humidity of the surrounding air only exceeding 65 % for a few weeks per year [SOURCE: EN 1995-1-1:2004, 2.3.1.3] Note to entry: In service class 1, which comprises typical indoor conditions, the average moisture content in most soft-woods will not exceed 12 % 3.3 service class climatic conditions characterised by a moisture content in the materials corresponding to a temperature of 20 °C and the relative humidity of the surrounding air only exceeding 85 % for a few weeks per year [SOURCE: EN 1995-1-1:2004, 2.3.1.3] Note to entry: In service class 2, to which most covered exterior conditions belong, the average moisture content in most soft-woods will not exceed 20 % 3.4 service class climatic conditions leading to higher moisture contents than in service class [SOURCE: EN 1995-1-1:2004, 2.3.1.3] Note to entry: Exterior conditions typically belong to service class 3.5 glue line adhesive layer between the wood members 3.6 close contact glue line (cc) glue line of thickness maximum 0,1 mm BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Note to entry: Close contact glue line is achieved by pressing together two plane wood members with a clamping pressure of (0,8 ± 0,1) N/mm2 without groves, spacers or similar device 3.7 thick glue line glue line of nominal thickness 0,3 mm to 2,0 mm Note to entry: Thick glue lines can be achieved by using spacers, grooves or similar devices Classification Adhesives for structural purpose shall produce joints of such strength and durability that the integrity of the bond is maintained in the assigned service class throughout the expected life of the structure EPI-adhesives according to EN 16254 are classified by Type (climate condition in use), Maximum test temperature and Maximum glue line thickness in use These three subclasses are subdivided as follows: Type I: To be used in service class and Type II: To be used in service class only Maximum test temperature: 50 °C, 70 °C or 90 °C Maximum glue line thickness in use: 0,1 mm, 0,2 mm and 0,3 mm Depending on the maximum glue line thickness in use, the adhesives are assigned to different application areas as described below and shown in Table — General purpose adhesives: to be used for glue lines between laminations (maximum glue line thickness 0,3 mm) and for finger joints in laminations — Small dimension adhesives: to be used in beams with a maximum cross section 45 000 mm2 (maximum glue line thickness 0,2 mm) and for finger joints in laminations The beam width shall not exceed 180 mm and the beam height shall not exceed 300 mm — Finger jointing adhesives: to be used for finger jointing of laminations and structural timber only (maximum glue line thickness 0,1 mm) The application of EPI shall always be in mixed state These adhesives shall be applied according to the manufacturer`s instructions NOTE The definition of General purpose and Type could be different in other standards BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Table — Adhesive classes Adhesive type designation Application area Max test temperature a Normal use Test General purpose 70 0,5 0,3 1, General purpose 90 0,5 0,3 1, Finger jointing 90 0,3 0,1 1, Special use EN 16254 I 90 0,2 EN 16254 I 90 0,1 EN 16254 I 70 0,2 EN 16254 I 70 0,1 EN 16254 II 50 0,3 EN 16254 II 50 0,2 EN 16254 II 50 0,1 a Small dimension 90 Small dimension 0,3 70 Finger jointing 0,3 70 General purpose 0,3 50 Small dimension 0,5 50 Finger jointing 0,3 50 0,3 mm Service classes °C EN 16254 I 70 0,3 EN 16254 I 90 0,3 Max glue line thickness Use 0,2 1, 0,2 1, 0,1 1, 0,3 0,2 0,1 Tested according to EN 15416–2 and Annex A in this standard, designation A6, A7 and A8 Table specifies the tests which shall be performed for each application area References are given to the actual subclause in this standard and to which standard the tests are based on Table — Necessary tests for adhesive use in difference application areas Application area General Purpose Small dimension Finger jointing a b EN 302– (based on 6.2)a EN 302– (based on 6.3) 0,1 X X 0,5 X Glue line thickness in test mm 0,3 0,1 0,2 X 0,3 X 0,3 X 0,1 X X X EN 302– (based on 6.4) EN 302– (based on 6.5) EN 15416–2 (based on 6.6)b X X X X X X X X EN 15416 –3 (based on 6.7) X X X Annex B in this standard (based on 6.8) X X X X X Climate treatment A1 to A5 and A6 or A7 or A8, depending on maximum test temperature (see Table and Annex A) Maximum test temperature according to Table BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Requirements 5.1 General Adhesives complying with this European Standard shall meet the performance requirements specified in 5.2 to 5.8 when tested in accordance with the following test methods: a) The tensile shear test (see 5.2 and 6.2) using bonded test pieces made from beech (Fagus sylvatica L.) b) The delamination test (see 5.3 and 6.3) on bonded test pieces made from Norway spruce (Picea abies L.) If the adhesive is to be used on wood from other conifers species like larch (Larix decidua), douglas fir (Pseudotsuga menziesii) and pines with coloured heartwood other than scots pine (Pinus sylvestris), from hardwood species and/or preservative treated wood, also prepare four laminated members using representative samples from those species or wood treated that way c) Tensile strength perpendicular to the glue line after climatic treatment (see 5.4 and 6.4) on bonded test pieces made from Norway spruce (Picea abies L.) The test will only be mandatory if the pH value in the mixed adhesive is lower than 3,0 d) The shrinkage stress test (see 5.5 and 6.5) on bonded test pieces made from Norway spruce (Picea abies L.) e) Static load test (see 5.6 and 6.6) on bonded test pieces made from beech (Fagus sylvatica L.) f) Creep deformation under bending shear (see 5.7 and 6.7) on test pieces made from Norway spruce (Picea abies L.) g) Long term sustained load test (see 5.8 and 6.8) under cyclic climate conditions perpendicular to the glue line on test pieces made from beech (Fagus sylvatica L.) All these tests are to be carried out with ready for use glue mixes, i.e adhesive and hardener mixed immediately before application These adhesives shall be applied according to the manufacturer`s instructions NOTE For application area Small dimension, requirements regarding product limitations and internal factory control by glulam production are given in the informative Annex C of this European Standard The adhesives in questions are EN 16254 I 70 02, EN 16254 I 90 02 and EN 16254 I I 50 02 5.2 Bond strength in longitudinal tensile shear test When tested in accordance with 6.2, the tensile shear strength values of close contact glue lines, 0,3 mm and 0,5 mm thick glue lines shall meet the requirements given in Table BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Table — Minimum mean tensile shear strength (N/mm2) for close contact, 0,3 mm and 0,5 mm thick glue lines after treatments according to Annex A Treatment Close contact 0,3 mm 0,5 mm (see Annex A) Type I Type II Type I Type II Type I Type II A1 A2 10,0 9,5 9,5 9,0 9,0 A3 6,0 10,0 8,0 8,0 7,6 7,6 7,2 7,2 A4 6,0 NRa A6 NRa A8 8,0 A5 8,0 A7 a 6,0 8,0 Treatment cycle not required NOTE 5,5 5,5 5,5 NRa 9,5 NRa NRa 7,2 NRa 7,6 NRa 7,2 5,0 5,0 5,0 NRa 8,3 NRa 7,2 NRa 6,5 NRa NRa 7,2 6,5 NRa NRa NRa In Table Type I adhesives includes: EN 16254 l 90 0,3 EN 16254 l 90 0,2 EN 16254 l 90 0,1 EN 16254 l 70 0,3 EN 16254 l 70 0,2 EN 16254 l 70 0,1 NOTE In Table Type II adhesives includes: EN 16254 ll 50 0,3 EN 16254 ll 50 0,2 EN 16254 ll 50 0,1 5.3 Resistance to delamination When tested in accordance with 6.3, the limits on delamination shall be those specified in Table Table — Resistance to delamination after treatment according to EN 302–2 Treatment Maximum delamination of any test sample Type I Low temperature High temperature 10 % of total glue line length Not required 5,0 Type II 10,0 Not required BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) NOTE In Table Type I adhesives includes: EN 16254 I 90 0,3 EN 16254 I 90 0,2 EN 16254 I 90 0,1 EN 16254 I 70 0,3 EN 16254 I 70 0,2 EN 16254 I 70 0,1 NOTE In Table Type II adhesives includes: EN 16254 II l 50 0,3 EN 16254 II 50 0,2 EN 16254 II 50 0,1 In the case of specific hardwood species 1), the following provisions apply: — The test shall be performed with the lamination and glulam cross-section and sawing patterns of the laminations conforming to the maximum sizes and the laminations sawing patterns used in the respective product — The maximum delamination shall be less than or equal to % for Type I adhesives and less than or equal to 12 % for Type II adhesives 5.4 Tensile strength perpendicular to the glue line after climatic treatment (acid damage test) When tested in accordance with 6.4, the average tensile strength of the untreated control samples shall not be lower than 2,0 N/mm2 The average tensile strength after cyclic treatment shall not be lower than 80 % of the average tensile strength of the untreated control samples 5.5 Effect of wood shrinkage on the shear strength When tested in accordance with 6.5, the average shear strength after climatic treatment shall not be lower than 1,5 N/mm2 5.6 Static load test of multiple glue line specimens in compression shear When tested in accordance with 6.6, not more than one of the six samples is allowed to fail during the test period The mean creep deformation of the bond lines in each of the remaining test samples shall not exceed 0,05 mm after the test 1) Oak (Quercus robur, Quercus petrea, Quersus alba) with a mean density of less than 830 kg/m3 11 BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) 5.7 Creep deformation test at cyclic climate conditions with specimens loaded in bending shear When tested in accordance with 6.7, the average ratio of the relative creep values of all five matched bending specimen pairs evaluated after t = 26 weeks, Rcmean (26 weeks), shall not be higher than 1,12 If the requirement is fulfilled, the test is completed If a larger average ratio is obtained, the test may be continued for a second period of 26 weeks and a second assessment shall be performed after a total of 52 weeks under load The average ratio of the relative creep value after 52 weeks, Rcmean (52 weeks), shall not be higher than 1,15 The load shall not be removed from the samples between the two test periods 5.8 Long term sustained load test at cyclic climate conditions with specimens loaded perpendicular to the glue line (“Glass house test”) When tested according to 6.8, not more than one of the 10 loaded samples for each climatic period (3, and 12 months) is allowed to fail during the test The mean tensile strength perpendicular to the glue line in each test series (control batch included) shall not be less than 5,0 N/mm2 Test methods 6.1 General The following test methods shall be used for establishing the requirements given in Clause 6.2 Determination of bond strength in longitudinal tensile shear test Tests shall be made in accordance with EN 302-1 but with close contact and 0,5 mm (application area General purpose) or 0,3 mm (application area Small dimension and Finger jointing) thick bond lines Climatic treatments shall be performed according to Annex A Test samples subjected to climatic treatment A6, A7 or A8 shall be wrapped airtight before treatment to reduce moisture loss The samples shall be tested immediately after removal from the climate chamber in a testing machine supplied with a temperature-controlled chamber 6.3 Determination of resistance to delamination Tests shall be made in accordance with EN 302-2 Bonded, laminated specimens are subjected to an impregnation-drying procedure The specimens are impregnated with water by immersing them and applying alternating high and low (vacuum) pressures They are then dried rapidly in a high velocity air stream by (65 ± 3) °C and 10 % to 15 % relative humidity for Type I adhesives, or 25 °C to 30 °C and (30 ± 5) % relative humidity for Type II adhesives The extent of open bond lines, delamination, as a result of these treatments is measured and compared with the total length of bond lines on both endgrain faces of the specimen 6.4 Determination of tensile strength perpendicular to the glue line after climatic treatment (acid damaged test) The test shall be made according EN 302-3, and will only be mandatory if the pH value in the mixed adhesive is lower than 3,0 The glue line thickness shall be 0,5 mm for application area General purpose, 0,3 mm for Small dimension and 0,1 mm for Finger jointing Care should be taken to prevent adhesive to escape from the glue line area (see Figure 1) 12 BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Dimensions in millimetres Key ledge from beech wood, glued on the wooden piece of same length (at least 800 mm) Figure — Suggestion for wooden ledges to prevent adhesive leakage 6.5 Determination of the effect of wood shrinkage on the shear strength Tests shall be made in accordance with EN 302-4 The bond line thickness shall be 0,5 mm for application area General purpose and 0,3 mm for Small dimension 6.6 Static load test of multiple glue line specimens in compression shear Tests shall be made in accordance with EN 15416-2, with the exception that climate 1, deviating from EN 15416-2, shall have a temperature as given in Table with the relative humidity and equilibrium moisture content unspecified Table — Test temperatures Adhesive type Application area EN 16254 II 50 0,3 General purpose EN 16254 II 50 0,1 Finger jointing EN 16254 II 50 0,2 EN 16254 I 70 0,3 EN 16254 I 70 0,2 EN 16254 I 70 0,1 EN 16254 I 90 0,3 EN 16254 I 90 0,2 EN 16254 I 90 0,1 Small dimension General purpose Small dimension Finger jointing General purpose Small dimension Finger jointing Temperature in test °C 50 70 90 13 BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) 6.7 Creep deformation test with specimens loaded in bending shear Tests shall be made in accordance with EN 15416-3 The bond line thickness shall be 0,3 mm for application area General purpose, 0,2 mm for Small dimension and 0,1 mm for Finger jointing 6.8 Long term sustained load test at cyclic climate conditions with specimens loaded perpendicular to the glue line (“Glass house test”) Test samples shall be made in accordance with Annex B in this standard The glue line thickness shall be close contact and 0,5 mm for application area General purpose, close contact and 0,3 mm for Small dimension and close contact for Finger joints Working properties of the adhesive 7.1 General The working properties to be determined are given in the relevant product standards 7.2 Determination of working life under reference conditions In some member states, it may be required to determine the conventional working life In this case, the conventional working life shall be determined according to EN 302-7 7.3 Determination of open assembly time under reference conditions In some member states, it may be required to determine the open assembly time In this case, the open assembly time shall be determined according to EN 15416-4 7.4 Determination of pressing time under reference conditions In some member states, it may be required to determine the pressing time In this case, the pressing time shall be determined according to EN 15416-5 The glue line thickness shall be 0,3 mm for application area General Purpose and 0,2 mm for application area Small dimension 14 BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Annex A (normative) Climatic treatment prior to shear test Assemblies are glued and thereafter conditioned for to 14 days in a standard climate of (20 ± 2) °C and (65 ± 5) % relative air humidity A longer conditioning time may be used if recommended by the adhesive manufacturer Test samples are prepared and treated according to Table A.1 Table A.1 — Climatic treatment prior to shear test Designation A1 A2 A3 A4 A5 Treatment Test immediately after the obligatory conditioning during days in standard climate 20/65 a days soaking in water at (20 ± 5) °C Samples tested in the wet state days soaking in water at (20 ± 5) °C Recondition in standard climate 20/65 a to original mass b Samples tested in the dry state h in boiling water h soaking in water at (20 ± 5) °C Samples tested in the wet state h in boiling water h soaking in water at (20 ± 5) °C Recondition in standard climate 20/65 a to original mass b A6 A7 A8 a b Samples tested in the dry state 72 h in 50 °C wrapped in aluminium foil Samples tested hot in temperature controlled test cabinet at (50 ± 2) °C 72 h in 70 °C wrapped in aluminium foil Samples tested hot in temperature controlled test cabinet at (70 ± 2) °C 72 h in 90 °C wrapped in aluminium foil Samples tested hot in temperature controlled test cabinet at (90 ± 2) °C The standard climate 20/65 is defined as temperature (20 ± 2) °C and a relative humidity of (65 ± 5) % Tolerance of the original mass within +2 % and −1 % 15 BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Annex B (normative) Glass house test B.1 General description The tests shall be performed with specimens according to EN 302-3 As a change to EN 302-3, the specimens are made from beech wood with a glue line thickness close contact and 0,5 mm for application area General purpose, close contact and 0,3 mm for Small dimension and close contact for Finger joints The beech wood boards from which the specimens are cut shall be free from knots, straight grained and shall have a density (700 ± 50) kg/m3 at 12 % moisture content The timber prior to specimen manufacture shall be conditioned in a climate chamber at storage conditions of (20 ± 2) °C and (65 ± 5) % RH The moisture content shall be (12 ± 1) % B.2 Production of the specimens In total, five sticks with a cross section of 50 mm x 60 mm and a length of at least 700 mm, enabling the cutting of eight test specimens and two reserve specimens from each stick of the specimen type described in EN 302-3, shall be manufactured for each glue line thickness The 10 specimens for each test are therefore made up of two specimens (see Figure B.2) from each stick Figure B.2 gives a view of the stick and of the cutting scheme for its subdivision into 10 specimens for the determination of the tensile strength perpendicular to the glue line The manufacture and build-up of the sticks shall follow the scheme shown in Figures B.1a) and B.1b) The annual ring orientation of both components glued together shall be roughly co-linear and shall be in the range of 30° to 60° NOTE For details of cutting, see EN 302–3 and Figure B.1 a) dimensions before cutting Key and 16 Dimensions in millimetres b) dimensions after planing positions of corners before cutting and after planing Figure B.1 — Cutting scheme of the components of the test sticks BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Dimensions in millimetres Key A current specimen numbers test batch (BC = control batch, BD x = Batch for a test after a duration of x months) reserve sample Figure B.2 — Cutting scheme for test stick and numbering of specimen B.3 Test procedure and climate conditions The test procedure shall consist of the following test series: a) short-term testing of a control batch BC of 10 specimens in ramp loading The specimens are tested after 14 days of conditioning in (20 ± 2) °C and (65 ± 5) % RH subsequent to gluing; b) long-term testing of batches BD3, BD6, BD12, each with 10 specimens, whereby each batch shall be subjected to a different duration of load time being 3, and 12 months All batches shall be subjected to the same constant stress level specified below At the end of each load period, all specimens of the respective batch not having failed shall be tested for residual tensile strength perpendicular to the glue line in ramp loading Constant stress equal in all three duration of load times shall be N/mm2 related to the net cross section of 25 mm x 50 mm The test climate shall be at natural outdoor conditions in Europe between latitude 45 and 60 degrees protected with light penetrable covering (“Glass house”) An alternative test procedure is to use a climate chamber with cyclically stepped climate varying stepwise with 24 h step length between two climates (10 ± 2) °C with (90 ± 5) % RH, and (35 ± 2) °C with (40 ± 5) % RH The specimens tested for residual strength after removal of the constant long-term load shall be conditioned at least for two weeks in climate (20 ± 2) °C and (65 ± 5) % RH before ramp loading 17 BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) B.4 Requirements The mean tensile strength perpendicular to the grain of the control batch BC and of each of the batches BD3, BD6 and BD12 tested for residual strength after 3, and 12 months of duration of load shall not be less than N/mm2 In each batch tested in long-term loading, only one specimen may fail within each of the respective load duration periods In case a specimen has failed in long-term loading, the mean value of the residual strength of the respective batch shall be calculated from the remaining nine specimens 18 BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Annex C (informative) Product limitations and glulam production control for beams produced with Small Dimension adhesives C.1 Product limitations The following restrictions exist: a) Straight glued laminated timber in coniferous wood with maximum lamellae width 180 mm and maximum beam height 300 mm can be produced In any case, the cross section shall not exceed 45 000 mm2 b) The nominal glue line thickness in the finished bonded product shall be limited to a maximum of 0,2 mm C.2 Control of the glue line thickness The allowed maximum nominal glue line thickness in use is 0,2 mm To control that the allowed thickness not exceed 0,2 mm, there shall be a daily control ensuring that the following tolerance limits for planing accuracy and parallelism is observed: a) Thickness variation within a lamella length of 1,0 m shall after planing not differ more than ± 0,1 mm from the mean value b) The difference in thickness measured along the two edges within a lamination length of 1,0 m shall after planing be less than 0,10 % of the lamella width If these criteria are fulfilled, and the recommendations from the adhesive suppliers are followed, the experience is that the produced bond line will comply with the thickness requirement 19 BS EN 16254:2013+A1:2016 EN 16254:2013+A1:2016 (E) Bibliography [1] [2] 20 EN 15425, Adhesives — One component polyurethane for load bearing timber structures — Classification and performance requirements EN 1995-1-1:2004, Eurocode 5: Design of timber structures — Part 1-1: General — Common rules and rules for buildings This page deliberately left blank NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW British Standards Institution (BSI) BSI is the national body responsible for preparing British Standards and other standards-related publications, information and services BSI is incorporated by Royal Charter British Standards and 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