Li ce ns ed C op y A ki n K ok sa l, B ec ht el L td , 1 2 D ec em be r 20 02 , U nc on tr ol le d C op y, ( c) B S I BRITISH STANDARD BS EN 12814 4 2001 Testing of welded joints of thermoplastic semi[.]
British Standard Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI A single copy of this British Standard is licensed to Akin Koksal 12 December 2002 This is an uncontrolled copy Ensure use of the most current version of this document by searching British Standards Online at bsonline.techindex.co.uk BRITISH STANDARD Testing of welded joints of thermoplastic semi-finished products — Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI Part 4: Peel test The European Standard EN 12814-4:2001 has the status of a British Standard ICS 83.080.20; 25.160.40 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW BS EN 12814-4:2001 BS EN 12814-4:2001 National foreword This British Standard is the official English language version of EN 12814-4:2001 The UK participation in its preparation was entrusted to Technical Committee PRI/80, Welding of plastics, which has the responsibility to: — aid enquirers to understand the text; — present to the responsible 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 Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI A list of organizations represented on this committee can be obtained 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 Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application Compliance with a British Standard does not of itself confer immunity from legal obligations This British Standard, having been prepared under the direction of the Sector Policy and Strategy Committee for Materials and Chemicals, was published under the authority of the Standards Policy and Strategy Committee on 09 November 2001 Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages to 16, an inside back cover and a back cover The BSI copyright date displayed in this document indicates when the document was last issued Amendments issued since publication Amd No © BSI 09 November 2001 ISBN 580 38617 Date Comments EUROPEAN STANDARD EN 12814-4 NORME EUROPÉENNE EUROPÄISCHE NORM September 2001 ICS 25.160.40 English version Testing of welded joints of thermoplastics semi-finished products - Part 4: Peel test Essai des assemblages soudés sur produits semi-finis en thermoplastiques - Partie 4: Essai de pelage Prüfen von Schweißverbindungen aus thermoplastischen Kunststoffen - Teil 4: Schälversuch This European Standard was approved by CEN on 16 August 2001 Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI 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 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 Management Centre has the same status as the official versions CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: rue de Stassart, 36 © 2001 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members B-1050 Brussels Ref No EN 12814-4:2001 E EN 12814-4:2001 (E) Contents page Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI Foreword Scope Normative references Terms and definitions 4 Symbols and designations 5 Peel test methods 6.1 6.2 6.3 6.4 6.5 6.6 6.7 T-peel test .5 Principle of the test Sampling procedures Dimensions of test specimens .6 Cutting of test specimens .7 Mechanical testing Test equipment Determination of the peel resistance 7.1 7.2 7.3 7.4 7.5 7.6 7.7 Decohesion test .9 Principle of the test Sampling procedure Conditioning Preparation of test specimens Test equipment 12 Mechanical testing .12 Calculation of joint toughness 12 8.1 8.2 8.3 8.4 8.5 Crush test .12 Principle of the test 12 Sampling procedure 13 Conditioning 14 Test equipment 14 Mechanical testing .14 Test report 15 EN 12814-4:2001 (E) Foreword This European Standard has been prepared by Technical Committee CEN/TC 249 "Plastics", the secretariat of which is held by IBN 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 March 2002, and conflicting national standards shall be withdrawn at the latest by March 2002 Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom EN 12814-4:2001 (E) Scope This standard specifies the dimensions, the method of sampling, the preparation of the test specimens, and also the conditions for performing the peel test perpendicular to the weld in order to determine the peel resistance and the failure behaviour A peel test may be used in conjunction with other tests (e.g tensile creep, macro ) to assess the performance of welded assemblies, made from thermoplastics materials Peel tests are applicable to overlap welded assemblies made from thermoplastics materials, irrespective of the welding process used Normative references This European Standard incorporates by dated or undated reference, provisions from other publications These normative references are cited at the appropriate places in the text and the publications are listed hereafter For dated references, subsequent amendments to, or revisions of, any of these publications apply to this standard only when incorporated in it by amendment or revision For undated references the latest edition of the publication referred to applies (including amendments) Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI EN 12814-5, Testing of welded joints of thermoplastics semi-finished products — Part : Macroscopic examination EN 13100-1, Non destructive testing of welded joints of thermoplastics semi-finished products — Part : Visual examination ISO 5893, Rubber and plastics test equipment — Tensile, flexural and compression types (constant rate of traverse) — Description ISO 13954, Plastics pipes and fittings — Peel decohesion test for polyethylene (PE) electrofusion assemblies of nominal outside diameter greater than or equal to 90 mm Terms and definitions For the purposes of this European standard, the following term and definition apply 3.1 peel resistance, f the arithmetic mean of the force values divided by the width of the test specimen (only relevant for T-peel test) EN 12814-4:2001 (E) Symbols and designations Symbols and designations are given in Table Table — Test specimen designations Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI Symbols and abbreviations Designations Units an Nominal thickness of test piece millimetre b Width of the test specimen millimetre c Maximum width of the air channel (if applicable) millimetre ci Initial crack size millimetre Dn Nominal diameter of tube millimetre Fw Maximum force measured during the test H Half thickness of decohesion test specimen K Apparent toughness Lc Clamped length of test specimen ligament millimetre Ld Length of fracture in the fusion plane millimetre Li Free length of test specimen millimetre Maximum width of the weld of the test specimen millimetre Lw a Pl Peel resistance Newton millimetre mega N.m N/mm -3/2 a For welds containing an air channel, Lw shall be taken as the width of the whole weld minus the width of the channel (c) Peel test methods Peel tests can be used to assess the performance of overlap joints in both welded sheet and pipe assemblies For assessing welded sheet assemblies the T-peel test shall be used as defined in clause This test is not applicable to welded test pieces containing sheets of different nominal thickness For electrofusion joints with nominal thickness of pipe/fitting greater than 10 mm, a decohesion test shall be used as defined in ISO 13954 or in clause For socket fusion joints, and for electrofusion joints with nominal outside diameter less than or equal to 90 mm, the crush test shall be used, as defined in clause The crush test can also be used for electrofusion joints with outside diameters greater than 90 mm 6.1 T-peel test Principle of the test The test consists of peeling a test specimen at a constant rate of displacement until it fractures, peels or yields 6.2 Sampling procedures The welded test specimens shall be cut perpendicular to the welded joint following a lapse of at least eight hours from welding EN 12814-4:2001 (E) Each test specimen shall be marked so that its original position in the test piece can be identified No heat treatment or mechanical straightening operations shall be carried out on the test specimen 6.3 Dimensions of test specimens The test specimen is shown in Figure and the dimensions are given in Table Lw Li an Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI Li b Lc Figure — T-peel test specimen The value of Lc shall be greater than, or equal to, b Table — Dimensions of test specimen Dimensions in millimetres a an ba Li an 1,5 15 15 1,5 < an 15 an < an 25 an an > 5 x an an For reinforced materials, b shall be 50 mm The tolerance for b shall be ± 0,5 mm EN 12814-4:2001 (E) 6.4 Cutting of test specimens The test specimens shall be cut with parallel sides as shown in Figure During cutting, heating of the test specimen should be avoided Cutting of the test specimen shall not produce notches After cutting, a macroscopic examination of the weld should be carried out, according to EN 12814-5 6.5 Mechanical testing The two unwelded ends of the test specimen shall be bent in opposite directions until each end is perpendicular to the weld, to form a T-shaped specimen (see Figure 2) for clamping in the jaws of the test equipment Inserting the test specimen into the test equipment shall not cause cracking at the weld If it does, the test is invalid Test specimen shall be conditioned to a temperature of (23 2) °C and unless otherwise specified, the test shall be carried out at a room temperature of ( 23 25 ) °C Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI The test speeds for some relevant thermoplastic materials are listed in Table Table — T-peel test speeds for some thermoplastics Material Speed mm/min PVC 10 PVDF, PP-H, PP-B 20 PE, PP-R 50 For other materials, the test speed shall be agreed between the contracting parties At least five test specimens shall be tested for each welded test piece The force shall be measured and recorded with an accuracy of % EN 12814-4:2001 (E) Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI Key jaws jaws Figure — Peel test arrangement In order to provide additional information, a graph of force versus crosshead displacement may be recorded for each specimen 6.6 Test equipment The test equipment shall conform to the requirements given in ISO 5893 The crosshead displacement shall be continuous, uniform and in accordance with Table The test equipment shall be provided with a suitable self-aligning grip to hold the specimen 6.7 Determination of the peel resistance The peel resistance is the arithmetic mean of the force values, FW , divided by the width of the test specimens, b, i.e Pl Fw b At least five test specimens shall be used in the evaluation of the peel resistance No test specimen shall be disregarded unless failure occurs in the clamps EN 12814-4:2001 (E) Decohesion test 7.1 Principle of the test A fused socket joint is sectioned at four equidistant positions around the circumference of the fitting and subjected to a longitudinal peel test, such that the resultant peel should be along the length of the fusion interface Separation of the joint components is taken to completion and the parted surfaces shall be inspected for evidence of ductile and/or brittle failure along the joint interface 7.2 Sampling procedure Each test specimen shall be cut from an assembly between a socket and a spigot end of a fitting or a pipe The number of test specimens tested shall be as specified in the relevant application standard 7.3 Conditioning Between the welding and machining operations, the test piece shall be conditioned for at least h at the ambient temperature of (23 ± 2) °C Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI After machining, the test specimen shall be continuously conditioned at the test temperature 7.4 Preparation of test specimens Initially standard test specimens shall be used for the decohesion test If the joint cannot be broken, using this test specimen, a side grooved test specimen shall be used (see 7.4.2) 7.4.1 Preparation of standard test specimens Following jointing and cooling to (23 ± 2) °C, the welded assembly shall be cut into rectangular sections see Figure Figure — Cutting test specimens Test specimens shall be cut, using a bandsaw or equivalent, spaced at equidistant intervals around the joint circumference The specimen length shall be half the length of the coupler Test specimen shall not include terminals To form a flat surface to act as a register for further machining, each test specimen shall be held flat on a linisher or worked with a saw or plane, in order to remove the curvature of the pipe surface see Figure EN 12814-4:2001 (E) Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI Key Linish/saw Cut rectangular sample Figure — Preparing test specimen A bandsaw or similar apparatus shall then be used to produce rectangular test specimens with flat parallel surfaces as shown in Figure For electrofusion joints with nominal outside diameter greater than 90 mm and up to and including 180 mm, the width b of the test specimen shall be 20 mm For tubes of nominal outside diameter greater than 180 mm, the width b of the test specimen shall be 30 mm One hole of at least mm diameter shall be drilled through the pipe and one hole of equal size through the fitting at the ends containing the "cold zones" see Figure 10 EN 12814-4:2001 (E) Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI Key Loading pins mm diameter holes in samples Figure — Loading arrangement The holes shall be located as close to each other as possible NOTE 7.4.2 Standard dimensions are not specified as individual manufacturer's dimensions vary Preparation of side grooved test specimens A mm wide side groove shall be machined in the test specimen, using a shaping machine (or similar apparatus) see Figure Figure — Side grooved test specimen 11 EN 12814-4:2001 (E) Grooves shall be machined into both faces of the test specimen, penetrating to a quarter of the specimen width The joint interface shall lie within the groove 7.5 Test equipment All tests shall be conducted on a tensile testing machine conforming to the requirements given in ISO 5893 The tensile testing machine shall incorporate a means of providing a permanent record of the force/displacement history during the test 7.6 Mechanical testing The test temperature shall be (23 ± 2) °C Push fit metal pins shall be placed in the holes drilled in the test specimen and drilled side plates attached which allow free movement during alignment see Figure The tensile force shall be applied using a cross-head rate of displacement of (25 ± 2,5) mm/min The test shall be continued until there is complete separation of the test specimen Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI A force/displacement graph shall be obtained for each test The maximum force (Fw) obtained during the test shall be recorded After failure has occurred, the size of the initial "crack" formed by the unfused section and cold zone shall be measured using a microscope and recorded The initial "crack" size (ci) shall be taken as the distance from the centre-line of the loading pin hole to the start of the joint This is defined by the presence of first signs of stress whitening due either to the onset of slow crack growth or ductile yielding NOTE Whatever the failure mode, a white zone can always by discerned at the origin of the initial "crack" The mode of failure shall be recorded by noting the location and length of either brittle crack growth (with no signs of macro-ductility) or ductile yielding as marked by intense white colouring and/or extensive cold-flow of the plastic material 7.7 Calculation of joint toughness For each joint tested, a value of the apparent toughness, K, shall be calculated using the equation : K NOTE 8.1 Fw ci H (3,46 2,38 ) 3/ ci bH When using side grooved samples, b shall be taken as the width across the ligament between the grooves Crush test Principle of the test A welded socket joint is sectioned in the axial direction in two equal parts The pipe is squeezed in order to assess the weld properties of the assembly 12 EN 12814-4:2001 (E) 8.2 Sampling procedure Each test specimen shall be cut from an assembly between a socket and a spigot end of a fitting or a pipe Two test specimens shall be cut from each welded assembly An example of a test specimen is shown in Figure Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI The number of test specimens tested shall be as specified in the relevant application standard 13 EN 12814-4:2001 (E) Dimensions in millimetres Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI 5dn Figure — Crush test specimen 8.3 Conditioning Between the fusion and machining operations, the test piece shall be conditioned for at least h at the ambient temperature of (23 ± 2) °C After machining, the test specimen shall be continuously conditioned at the test temperature 8.4 Test equipment All tests shall be carried out on compression equipment, capable of applying the necessary compressive force 8.5 Mechanical testing The pipe of each test specimen shall be squeezed approximately mm from the mouth of the socket (see Figure 8) until the internal pipe surfaces touch, i.e the distance between the jaws of the squeezing equipment becomes equal to twice the pipe wall thickness The assembly shall be held in this position for ten minutes, at the end of which, the fused interface shall be inspected and the length of fracture in the fusion plane, parallel to the axis of the pipe, Ld, shall be measured 14 EN 12814-4:2001 (E) Dimensions in millimetres >5Dn (approx) >5Dn Licensed Copy: Akin Koksal, Bechtel Ltd, 12 December 2002, Uncontrolled Copy, (c) BSI