Imperfections in thermoplastic welds - Classification

This document specifies a system for classifying imperfections that may be encountered in thermoplastic welded joints during manufacture and provides examples of imperfections for the following welding processes:
-   heated tool butt welding;
-   heated tool socket welding;
-   electrofusion socket welding;
-   hot gas welding;
-   extrusion welding;
-   solvent socket welding.
This document does not describe imperfections that may be generated during service or imperfections present before welding, which are due to poor preparation or assembly of components (e.g. fit up). The correct preparation and assembly of components (e.g. fit up) are described in the relevant welding procedure specification (WPS).
This document is also not concerned with the search for the possible influence of these imperfections on the behaviour of joints in relation to the different types of stress to which the latter may be subjected or on methods for preventing such imperfections.
This document can be used in conjunction with EN 16296 [1] to determine the acceptance of welds.
Only imperfections giving rise to discontinuities of materials or changes in shape are taken into consideration in this document, specifying their type, their shape and their positions. This classification can be used to determine the possible origin or causes of the imperfections.

Unregelmäßigkeiten an Schweißverbindungen von thermoplastischen Kunststoffen - Einteilung

Dieses Dokument legt ein System zur Einteilung von Unregelmäßigkeiten, die während der Herstellung in Schweißverbindungen von thermoplastischen Kunststoffen auftreten können, fest und enthält Beispiele von Unregelmäßigkeiten für die folgenden Schweißverfahren:
-   Heizelementstumpfschweißen;
-   Heizelementmuffenschweißen;
-   Heizwendelmuffenschweißen (E-Muffenschweißen);
-   Warmgasschweißen;
-   Extrusionsschweißen;
-   Klebemuffenschweißen (Diffusionskleben).
Dieses Dokument beschreibt keine Unregelmäßigkeiten, die während des Betriebs entstehen können oder vor dem Schweißen vorhanden sind, die auf mangelhafte Vorbereitung oder Zusammensetzung der Bestand¬teile (z. B. mangelhafte Passung) zurückzuführen sind. Die ordnungsgemäße Vorbereitung und Zusammen¬setzung der Komponenten (z. B. Passung) ist in der entsprechenden Schweißanweisung (WPS, en: Welding Procedure Specification) beschrieben.
Dieses Dokument befasst sich auch nicht mit der Suche nach möglichen Auswirkungen dieser Unregel-mäßigkeiten auf das Verhalten von Verbindungen in Bezug auf die unterschiedlichen Belastungen, denen diese Verbindungen ausgesetzt sein können, oder mit Verfahren zur Vermeidung solcher Unregelmäßig-keiten.
Dieses Dokument kann im Zusammenhang mit EN 16296 [1] für die Bewertung von Schweißnähten ver-wendet werden.
Nur Unregelmäßigkeiten, die Inhomogenitäten der Werkstoffe oder Formveränderungen zur Folge haben, sind in diesem Dokument berücksichtigt und zwar unter Angabe ihrer Art, ihrer Form und ihrer Lage. Diese Einteilung kann zur Bestimmung des möglichen Ursprungs oder der Ursachen von Unregelmäßigkeiten ver¬wendet werden.

Défauts dans les assemblages soudés en thermoplastiques - Classification

Le présent document  spécifie un système de classification des défauts susceptibles d’être rencontrés dans les assemblages soudés en thermoplastiques lors de la fabrication et fournit des exemples de défauts pour les procédés de soudage suivants :
-   soudage bout à bout par élément chauffant ;
-   soudage d’emboîture par élément chauffant ;
-   soudage d’emboîture par électrofusion ;
-   soudage au gaz chaud ;
-   soudage par extrusion ;
-   soudage d’emboîture par adhésif.
Le présent document ne décrit pas les défauts qui pourraient être générés au cours du service ni les défauts présent avant le soudage, qui sont causés par une mauvaise préparation ou un mauvais assemblage des composants (par exemple, l'ajustement). La bonne préparation et le bon assemblage des composants (par exemple, l’ajustement) sont décrits dans la spécification des modes opératoires de soudage (WPS) correspondante.
Le présent document ne traite également pas de la recherche de l’éventuelle influence de ces défauts sur le comportement des assemblages en fonction des différents types de contraintes auxquels ces derniers peuvent être soumis ni sur les méthodes pour éviter de tels défauts.
Le présent document peut être utilisé conjointement avec l'EN 16296 [1] pour déterminer  l’acceptation des soudures.
Seuls les défauts donnant lieu à des discontinuités de matériau ou à des modifications de forme sont pris en compte dans le présent document, en spécifiant leur type, leur forme et leurs positions. Cette classification peut être utilisée pour déterminer les possibles origines ou causes des défauts.

Napake v plastomernih zvarih - Razvrstitev

Ta evropski standard določa sistem za razvrstitev napak, ki se lahko pojavijo v plastomernih zvarnih spojih med izdelavo, in podaja primere napak pri naslednjih postopkih varjenja:
–   soležno varjenje z ogrevanim orodjem;
–   obojno varjenje z ogrevanim orodjem;
–   elektrofuzijsko obojno varjenje;
–   varjenje z vročim plinom;
–   ekstrudersko varjenje;
–   obojno varjenje s topilom.
Ta dokument ne opisuje napak, ki se lahko pojavijo med uporabo, ali napak, ki so prisotne pred varjenjem, kot je npr. slabo prileganje. Pravilna priprava (npr. prileganje) je opisana v ustrezni specifikaciji varilnega postopka (WPS). Ta dokument prav tako ne obravnava iskanja morebitnega vpliva teh napak na obnašanje spojev v povezavi z različnimi vrstami obremenitev, ki so jim spoji lahko podvrženi, ali metod za preprečevanje takšnih napak.
Zato tega dokumenta ni mogoče uporabiti za določevanje sprejemljivosti zvarov, kar je opredeljeno v standardu EN 16296 [1].
Ta dokument obravnava samo napake, ki povzročajo nehomogenost materialov ali spremembe oblike, in sicer določa njihovo vrsto, obliko ter položaj. Ta razvrstitev se lahko uporabi za določanje možnega izvora ali vzrokov napak.

General Information

Status
Published
Publication Date
19-Feb-2019
Current Stage
6060 - Definitive text made available (DAV) - Publishing
Due Date
20-Feb-2019
Completion Date
20-Feb-2019

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Napake v plastomernih zvarih - RazvrstitevUnregelmäßigkeiten an Schweißverbindungen von thermoplastischen Kunststoffen - EinteilungDéfauts dans les assemblages soudés en thermoplastiques - ClassificationImperfections in thermoplastic welds - Classification83.080.01Polimerni materiali na splošnoPlastics in general25.160.40Varjeni spoji in variWelded joints and weldsICS:Ta slovenski standard je istoveten z:EN 14728:2019SIST EN 14728:2019en,fr,de01-maj-2019SIST EN 14728:2019SLOVENSKI

STANDARDSIST EN 14728:20051DGRPHãþD
SIST EN 14728:2019
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 14728
February
t r s { ICS
t wä s x rä v r Supersedes EN
s v y t zã t r r wEnglish Version

Imperfections in thermoplastic welds æ Classification Dßfauts dans les assemblages soudßs en thermoplastiques æ Classification

Unregelmäßigkeiten an Schweißverbindungen von thermoplastischen Kunststoffen æ Einteilung This European Standard was approved by CEN on

s v December
t r s zä

egulations which stipulate the conditions for giving this European Standard the status of a national standard without any alterationä Upætoædate lists and bibliographical references concerning such national standards may be obtained on application to the CENæCENELEC Management Centre or to any CEN memberä

translation under the responsibility of a CEN member into its own language and notified to the CENæCENELEC Management Centre has the same status as the official versionsä

CEN members are the national standards bodies of Austriaá Belgiumá Bulgariaá Croatiaá Cyprusá Czech Republicá Denmarká Estoniaá Finlandá Former Yugoslav Republic of Macedoniaá Franceá Germanyá Greeceá Hungaryá Icelandá Irelandá Italyá Latviaá Lithuaniaá Luxembourgá Maltaá Netherlandsá Norwayá Polandá Portugalá Romaniaá Serbiaá Slovakiaá Sloveniaá Spainá Swedená Switzerlandá Turkey and United Kingdomä

EUROPEAN COMMITTEE FOR STANDARDIZATION COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre:
Rue de la Science 23,
B-1040 Brussels

t r s { CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Membersä Refä Noä EN

s v y t zã t r s { ESIST EN 14728:2019

EN 14728:2019 (E) 2 Contents Page European foreword ...................................................................................................................................................... 3 1 Scope ............................................................................................................................................................................ 4 2 Normative references ............................................................................................................................................ 4 3 Terms and definitions ............................................................................................................................................ 4 4 Definition and classification of imperfections .............................................................................................. 5 Annex A (normative)

Explanations for each character ..................................................................................29 Bibliography .................................................................................................................................................................33

SIST EN 14728:2019

EN 14728:2019 (E) 3 European foreword This document (EN 14728:2019) 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 publication of an identical text or by endorsement, at the latest by August 2019, and conflicting national standards shall be withdrawn at the latest by August 2019. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights. This document supersedes EN 14728:2005. In comparison with the previous edition, the following technical modifications have been made: — Clause 3, Symbols and designations, has been deleted; — examples of imperfections for the different welding processes are in Tables 1 to 6; — in Annex A (normative) in the heading, no more reference to CEN ISO/TS 17845; — in the text of Annex A, Table A.1 — Definition of the first character and Table A.2 — Definition of the second character, have been added. 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, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 14728:2019

EN 14728:2019 (E) 4 1 Scope This document specifies a system for classifying imperfections that may be encountered in thermoplastic welded joints during manufacture and provides examples of imperfections for the following welding processes: — heated tool butt welding; — heated tool socket welding; — electrofusion socket welding; — hot gas welding; — extrusion welding; — solvent socket welding. This document does not describe imperfections that may be generated during service or imperfections present before welding, which are due to poor preparation or assembly of components (e.g. fit up). The correct preparation and assembly of components (e.g. fit up) are described in the relevant welding procedure specification (WPS). This document is also not concerned with the search for the possible influence of these imperfections on the behaviour of joints in relation to the different types of stress to which the latter may be subjected or on methods for preventing such imperfections. This document can be used in conjunction with EN 16296 [1] to determine the acceptance of welds. Only imperfections giving rise to discontinuities of materials or changes in shape are taken into consideration in this document, specifying their type, their shape and their positions. This classification can be used to determine the possible origin or causes of the imperfections. 2 Normative references The following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN 12201-3:2011+A1:2012, Plastics piping systems for water supply, and for drainage and sewerage under pressure - Polyethylene (PE) - Part 3: Fittings 3 Terms and definitions No terms and definitions are listed in this document. ISO and IEC maintain terminological databases for use in standardization at the following addresses:

IEC Electropedia: available at http://www.electropedia.org/

ISO Online browsing platform: available at http://www.iso.org/obp SIST EN 14728:2019

EN 14728:2019 (E) 5 4 Definition and classification of imperfections The numbering system used for the classification of imperfections shall be as defined in Annex A. Examples of imperfections in thermoplastics welded joints are given in the following tables: — Heated tool butt weld: Table 1; — Heated tool socket weld: Table 2; — Electrofusion socket weld: Table 3; — Hot gas weld: Table 4; — Extrusion weld: Table 5; — Solvent socket weld: Table 6. An explanation of each character used in the imperfection numbering system is given in Annex A. Table 1 — Heated tool butt weld Number Designation Description Illustration 2BAAA Gas cavity Cavity formed by evolution or entrapment of gas(es). This cavity is distinguishable by having a similar colour as the surrounding material. It could be: Spherical Elongated Tubular (wormhole).

2CAAI Shrinkage cavity Cavity due to shrinkage of weld during solidification. This cavity may be distinguishable by evidence of ductility or stress whitening.

2MAAA
Surface bubble On weld bead.
SIST EN 14728:2019
EN 14728:2019 (E) 6 Number Designation Description Illustration 3AAAI 3AAAF

Particulate inclusion Foreign material trapped at weld interface. Foreign material on surface of weld beads.

3JAAI Parent material inclusion Inclusion of parts of parent material at weld interface.

3KAAI 3KAAF

Degraded polymer Inclusion of decomposition products at weld interface. Inclusion of decomposition products on surface of weld beads.

4BAAA Lack of fusion No fusion across weld interface.

4QBAF Groove in upset or reinforcement Excessive groove depth at centre of weld bead.

4WAAA Cold fusion Incomplete fusion across weld interface.
SIST EN 14728:2019

EN 14728:2019 (E) 7 Number Designation Description Illustration 5CAAAa Incorrect weld profile Deviation of the specified shape of the weld bead.

5EIAAa Linear misalignment Deviation from specified tolerances in coplanarity between two welded pieces.

5EJAAa Angular misalignment Deviation from specified angle between two welded pieces.

5GAAAa Irregular width Excessive variation in weld or bead width.
6DAAAa Excessive width Width of the weld bead greater than specified.
6HAAAa Excessive asymmetry of welds Asymmetric weld bead.

6MAAAa Insufficient upset material Upset material smaller than the specified value.

SIST EN 14728:2019

EN 14728:2019 (E) 8 Number Designation Description Illustration 7BAAA Thermal damage outside of welding Surface alteration resulting from the accidental action of a source of heat.

7VAAAa Excessive toe in Deviation between the outside diameter at the end of the pipe and the outside diameter remote from the pipe end.

9CAAA Tool mark Local damage due to clamping.
Key
good fusion at interface
cold fusion at interface

lack of fusion at interface a Not applicable to fabricated fittings according to EN 12201-3:2011+A1:2012, Annex B. SIST EN 14728:2019

EN 14728:2019 (E) 9 Table 2 — Heated tool socket weld Number Designation Description Illustration 2CAAA Shrinkage cavity Cavity due to shrinkage of weld during solidification.

2MAAA Surface bubble On weld bead.

3AAAF 3AAAI Particulate inclusion Foreign material trapped in the weld and/or on the surface of the weld bead.

SIST EN 14728:2019

EN 14728:2019 (E) 10 Number Designation Description Illustration 3KAAF 3KAAI Degraded polymer Inclusion of decomposition products at the weld interface and/or on the surface of the weld bead.

4BAAA Lack of fusion Area of no fusion between pipe and fitting.
4CAAA
Incomplete penetration Insufficient penetration of the pipe(s) into the socket.
4PAAA Material extrusion Extrusion of material from the joint (sheeting).
SIST EN 14728:2019

EN 14728:2019 (E) 11 Number Designation Description Illustration 4RAAA Excessive penetration Pipe is inserted beyond the centre stop of the fitting.

4WAAA Cold
fusion Incomplete fusion around the circumference of
joint.
5EJAA
Angular misalignment Deviation of alignment between pipe and fitting.
5GAEF Irregular width Excessive variation of the width of the weld bead.
6DAAA Excessive width Excessive weld bead dimension.
SIST EN 14728:2019
EN 14728:2019 (E) 12 Number Designation Description Illustration 6HAAA
Excessive asymmetry Deviation from specified weld bead shape.
6MAAA Insufficient upset material Weld bead smaller than the specified value.

7BAAA Thermal damage Surface alteration resulting from the accidental action of a source of heat.

9CAAA Tool mark Local damage due to weld preparation tool.
Key
cold fusion at interface

good fusion at interface NOTE All imperfections can occur on one or both sides of the joi

...

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