1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationImperfections in thermoplastics welded joints Quality levelsBS EN 16296:2012National forewordThis British Standard is the UK implementation of EN 16296:2012.The UK participation
2、in its preparation was entrusted to Technical CommitteePRI/80, Welding thermoplastics.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 i
3、ts correct application. The British Standards Institution 2012Published by BSI Standards Limited 2012 ISBN 978 0 580 75090 8 ICS 25.160.40Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy a
4、nd Strategy Committee on 30 November 2012.Amendments issued since publicationDate Text affectedBRITISH STANDARDBS EN 16296:2012EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 16296 October 2012 ICS 25.160.40 English Version Imperfections in thermoplastics welded joints - Quality levels Dfauts d
5、ans les assemblages souds en thermoplastiques - Niveaux de qualit Unregelmigkeiten an Schweiverbindungen von thermoplastischen Kunststoffen - Qualittsstufen This European Standard was approved by CEN on 22 September 2012. CEN members are bound to comply with the CEN/CENELEC Internal Regulations whic
6、h 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 Eur
7、opean 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 a
8、re 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, R
9、omania, 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 2012 CEN All rights of exploitation in any form and by any mean
10、s reserved worldwide for CEN national Members. Ref. No. EN 16296:2012: EBS EN 16296:2012EN 16296:2012 (E) 2 Contents Page Foreword . 3Introduction 41 Scope . 52 Normative reference . 63 Terms and definitions 64 Quality levels. 64.1 Classification . 64.2 Choice of quality level 75 Requirements for we
11、lded joints 7Bibliography . 18BS EN 16296:2012EN 16296:2012 (E) 3 Foreword This document (EN 16296:2012) has been prepared by Technical Committee CEN/TC 249 “Plastics”, the secretariat of which is held by NBN. This European Standard shall be given the status of a national standard, either by publica
12、tion of an identical text or by endorsement, at the latest by April 2013, and conflicting national standards shall be withdrawn at the latest by April 2013. 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
13、not be held responsible for identifying any or all such patent rights. According to the CEN/CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmar
14、k, 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 16296:2012
15、EN 16296:2012 (E) 4 Introduction This European Standard should be used as a reference in drafting of application codes and/or other application standards. It contains a simplified selection of imperfections based on the designations given in EN 14728, Imperfections in thermoplastic welds Classificat
16、ion. Some imperfections according to EN 14728 have been used directly and some have been grouped together. The basic numerical referencing system from EN 14728 has been used. The purpose of this standard is to define quality levels based on typical imperfections, which might occur in normal fabricat
17、ion. It may be used within a quality system for the production of factory welded joints. It provides three sets of dimensional values from which a selection can be made for a particular application. The quality level necessary in each case should be defined by the application standard or the fabrica
18、tor in conjunction with the user and/or other parties concerned. The level should be prescribed before the start of production, preferably at the enquiry or order stage. The quality levels given in this standard are intended to provide basic reference data and are not specifically related to any par
19、ticular application. They refer to the types of welded joints in a fabrication and not to the complete product or component itself. It is possible, therefore, that different quality levels are applied to individual welded joints in the same product or component. The choice of quality level for any a
20、pplication should take account of design considerations, subsequent processing, mode of stressing (e.g. static, dynamic), service conditions (e.g. pressure, temperature, environment) and consequences of failure. Economic factors are also important and should include not only the cost of welding but
21、also of inspection, test and repair. Although this European Standard includes types of imperfections relevant to the processes given in Clause 1, only those which are applicable to the process and application in question need to be considered. Imperfections are quoted in terms of their actual dimens
22、ions. However their detection and evaluation may require the use of one or more methods of non-destructive testing. It should be noted that the detection and sizing of imperfections is dependent on the inspection methods and the extent of testing specified in the application standard or contract. Th
23、e need for detection is not the subject of this standard. This European Standard is directly applicable to visual examination of welds or test specimens. It does not include details of recommended methods of detection and sizing. The indication provided by non-destructive testing should not be used
24、directly for the evaluation of quality levels. Therefore, it needs to be supplemented by requirements for examinations, inspection and testing. BS EN 16296:2012EN 16296:2012 (E) 5 1 Scope This European Standard provides quality levels for imperfections in thermoplastics welded joints. It applies to
25、material thickness above 2,0 mm. Three quality levels are given in order to permit application for a wide range of welded fabrication. They are designated by symbols B, C and D, where B is the most stringent. The quality levels refer to production quality and not to the fitness-for-purpose (see 3.2)
26、 of the manufactured product. This European Standard applies to the following thermoplastic materials: Table 1 Abbreviation Material description ABS Acrylonitrile-butadiene-styrene plastic ECTFE Ethylene-chlorotrifluoroethylene copolymer FEP Fluorinated ethylene propylene PB Polybutylene PE Polyethy
27、lene PFA Perfluoroalkoxy PP-B Polypropylene block copolymer PP-H Polypropylene homopolymer PP-R Polypropylene random copolymer PVC-C Chlorinated polyvinyl chloride PVC-U Unplasticised polyvinyl chloride (rigid PVC) PVDF Polyvinylidene fluoride and to the following welding processes: Heated tool weld
28、ing; Electrofusion welding; Hot gas welding using filler rod only; Extrusion welding; BS EN 16296:2012EN 16296:2012 (E) 6 Solvent welding of pipes. 2 Normative reference The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its applicatio
29、n. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 14728, Imperfections in thermoplastic welds Classification 3 Terms and definitions For the purposes of this document, the following te
30、rms and definitions apply 3.1 quality level description of the qualities of a weld on the basis of type and size of selected imperfections 3.2 fitness-for-purpose ability of a product, process or service to serve a defined purpose under specific conditions 4 Quality levels 4.1 Classification Three q
31、uality levels are defined as B, C and D in order to permit application for a wide range of welded fabrications (see Table 2). Table 2 Quality levels for weld imperfections Symbol Requirement B Stringent C IntermediateD Moderate The purpose of this standard is to define quality levels based on typica
32、l imperfections, which might occur in normal fabrications and are classified in EN 14728. It may be used within a quality system for the production of factory welded joints. It provides three sets of dimensional values from which a selection can be made for a particular application. The quality leve
33、l necessary in each case should be defined by the application standard or the fabricator in conjunction with the user and/or other parties concerned. The level should be prescribed before the start of production, preferably at the enquiry or order stage. For specific applications, additional require
34、ments not covered by this standard may need to be prescribed. These additional requirements shall be defined as quality level A. BS EN 16296:2012EN 16296:2012 (E) 7 4.2 Choice of quality level For the choice of the quality level, the following factors, among others, shall be taken into account: mech
35、anical loading (static, dynamic); environment (media, temperature); material properties (ductile, brittle); manufacturing conditions (workshop, construction site, welding in constrained condition); operating conditions; potential danger in the event of failure. 5 Requirements for welded joints The r
36、equirements for the above mentioned quality levels (B, C and D) are listed as follows: Heated tool butt welds: Table 3; Heated tool socket welds: Table 4; Electrofusion welds: Table 5; Hot gas welds: Table 6; Extrusion welds: Table 7; Solvent welds in pipes: Table 8. Different types of imperfection
37、occurring simultaneously at any cross-section of the joint may need special consideration and advice should be sought from the product manufacturer. Any two adjacent imperfections separated by a distance smaller than the major dimension of the smaller imperfection shall be considered as a single imp
38、erfection. In certain circumstances, it is necessary to machine the completed weld. In this case, the weld shall be examined both before and after machining. BS EN 16296:2012EN 16296:2012 (E) 8 Table 3 Definition of quality levels for heated tool butt welds Number Designations Level B Level C Level
39、D 1AAAA Cracks Not permissible Not permissible Not permissible 2BAAA Gas cavity Isolated cavities permissible if diameter 5 % of wall thickness Permissible if diameter of largest cavity 10 % of wall thickness Permissible if diameter of largest cavity 15 % of wall thickness 2CAAA Shrinkage cavity Iso
40、lated cavities permissible if diameter 5 % of wall thickness Permissible if diameter of largest cavity 10 % of wall thickness Permissible if diameter of largest cavity 15 % of wall thickness 2DAAA Craze Not permissible Not permissible Not permissible 3AAAA Inclusion Isolated inclusion permissible if
41、 maximum dimension 5 % of wall thickness Isolated and rows of inclusions permissible if maximum dimension 10 % of wall thickness Isolated and rows of inclusions permissible if maximum dimension 15 % of wall thickness 3KAAA Degraded polymer Not permissible Not permissible Not permissible 4BAAA Lack o
42、f fusion Not permissible Not permissibleNot permissible 5AAAA Imperfect shape Mechanical testing of sample welds is recommended Mechanical testing of sample welds is recommended Mechanical testing of sample welds is recommended 5EJAA Linear misalignment Permissible if misalignment is not greater tha
43、n 10 % of the wall thickness Permissible if misalignment is not greater than 15 % of the wall thickness Permissible if misalignment is not greater than 20 % of the wall thickness 5EKAA Angular misalignment Permissible if misalignment is not greater than 0,2 Permissible if misalignment is not greater
44、 than 0,4 Permissible if misalignment is not greater than 0,8 5HAAA Irregular surface Not permissible Not permissible Not permissible 6EAAA Excessive upset Not permissible Not permissible Not permissible 6HAAA 6HAAC Excessive asymmetry of welds Permissible if smaller half of weld bead is not less th
45、an 70 % of Permissible if smaller half of weld bead is not less than 60 % of Permissible if smaller half of weld bead is not less than 50 % of BS EN 16296:2012EN 16296:2012 (E) 9 Number Designations Level B Level C Level D larger half of weld bead around the whole circumference larger half of weld b
46、ead around the whole circumference larger half of weld bead around the whole circumference 7BAAA Thermal damage Not permissible Not permissible Not permissible 9CAAA Tool mark Locally permissible if bottom of notch is not acute and the notch depth is less than 10 % of the wall thickness and not grea
47、ter than 0,5 mm Locally permissible if bottom of notch is not acute and the notch depth is less than 10 % of the wall thickness and not greater than 1,0 mm Locally permissible if bottom of notch is not acute and the notch depth is less than 15 % of the wall thickness and not greater than 2,0 mm NOTE
48、 The data in this table can also be found in DVS 2202-1 1. BS EN 16296:2012EN 16296:2012 (E) 10 Table 4 Definition of quality levels for heated tool socket welds Number Designations Level B Level C Level D 2BAAA Gas cavity Isolated cavities permissible if diameter 5 % of insertion length Permissible
49、 if diameter of largest cavity 10 % of wall thickness Permissible if diameter of largest cavity 15 % of wall thickness 2DAAA Craze Not permissible Not permissible Not permissible 3AAAA Inclusion Isolated inclusion permissible if maximum dimension 5 % of fusion length Isolated and rows of inclusions permissible if maximum dimension 10 % of fusion length Isolated and rows of inclusions permissible if maximum dimension 15 % of fusion length 3KAAA Degraded
