EN 16296:2021
(Main)Imperfections in thermoplastics welded joints - Quality levels
Imperfections in thermoplastics welded joints - Quality levels
This document specifies quality levels for imperfections in thermoplastics welded joints that have cooled to ambient temperature and is applicable to material thickness above 2,0 mm.
Three quality levels are specified 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) of the manufactured product.
The quality level necessary are expected to be defined by the application standard or by the fabricator in conjunction with the user and/or other parties concerned. The level is expected to be prescribed before the start of production, preferably at the enquiry or order stage.
This document applies to the following thermoplastic materials in Table 1:
and to the following welding processes:
- heated tool welding;
- electrofusion socket welding;
- hot gas welding using filler rod only;
- extrusion welding;
- solvent welding of pipes.
Unregelmäßigkeiten an Schweißverbindungen von thermoplastischen Kunststoffen - Qualitätsstufen
Dieses Dokument legt Qualitätsstufen für Unregelmäßigkeiten an Schweißverbindungen von thermo-plastischen Kunststoffen fest, die auf Umgebungstemperatur abgekühlt sind, und gilt für Materialdicken über 2,0 mm.
Um eine Anwendung für eine große Auswahl von Schweißerzeugnissen zu ermöglichen, sind drei Qualitäts¬stufen festgelegt. Diese sind durch Symbole B, C und D gekennzeichnet, wobei B die höchste Qualitätsstufe ist. Die Qualitätsstufen beziehen sich auf die Fertigungsqualität und nicht auf die Gebrauchstauglichkeit (siehe 3.2) des hergestellten Produkts.
Es wird davon ausgegangen, dass die für den jeweiligen Fall erforderliche Qualitätsstufe durch die Anwendungsnorm oder vom Hersteller zusammen mit dem Anwender und/oder sonstigen Parteien festgelegt wird. Es wird davon ausgegangen, dass die Qualitätsstufe vor dem Fertigungsbeginn, vorzugs-weise bei der Anfrage oder Bestellung, festgelegt wird.
Dieses Dokument gilt für die folgenden thermoplastischen Materialien in Tabelle 1:
und die folgenden Schweißverfahren:
- Heizelementschweißen;
- Heizwendelmuffenschweißen;
- Warmgasschweißen, ausschließlich unter Anwendung von Schweißstab;
- Extrusionsschweißen;
- Quellschweißen von Rohren.
Défauts dans les assemblages soudés en thermoplastiques - Niveaux de qualité
Le présent document spécifie les niveaux de qualité pour les défauts des assemblages soudés en thermoplastiques qui ont refroidi à la température ambiante et s'applique aux matériaux présentant une épaisseur supérieure à 2,0 mm.
Trois niveaux de qualité sont spécifiés afin de permettre l'application à une large gamme d'assemblages soudés. Ils sont désignés par les symboles B, C et D, B étant le niveau le plus contraignant. Les niveaux de qualité s'appliquent à la qualité de la production et non pas à l'aptitude à l'emploi (voir 3.2) du produit fabriqué.
Le niveau de qualité nécessaire devrait être défini par la norme d'application ou par le fabricant en collaboration avec l'utilisateur et/ou d'autres parties concernées. Le niveau est supposé être prescrit avant le démarrage de la production, de préférence au moment de la consultation ou de la commande.
Le présent document s'applique aux matériaux thermoplastiques suivants dans le Tableau 1:
et aux procédés de soudage suivants :
- soudage par outil chauffant ;
- soudage par emboîture électrosoudable ;
- soudage au gaz chaud avec baguette d’apport uniquement ;
- soudage par extrusion ;
- collage au solvant de tubes.
Nepravilnosti v zvarjenih spojih plastomerov - Stopnje kakovosti
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-julij-2021
Nadomešča:
SIST EN 16296:2014
Nepravilnosti v zvarjenih spojih plastomerov - Stopnje kakovosti
Imperfections in thermoplastics welded joints - Quality levels
Unregelmäßigkeiten an Schweißverbindungen von thermoplastischen Kunststoffen -
Bewertungsgruppen
Défauts dans les assemblages soudés en thermoplastiques - Niveaux de qualité
Ta slovenski standard je istoveten z: EN 16296:2021
ICS:
25.160.40 Varjeni spoji in vari Welded joints and welds
83.080.20 Plastomeri Thermoplastic materials
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EN 16296
EUROPEAN STANDARD
NORME EUROPÉENNE
May 2021
EUROPÄISCHE NORM
ICS 25.160.40 Supersedes EN 16296:2012
English Version
Imperfections in thermoplastics welded joints - Quality
levels
Défauts dans les assemblages soudés en Unregelmäßigkeiten an Schweißverbindungen von
thermoplastiques - Niveaux de qualité thermoplastischen Kunststoffen - Qualitätsstufen
This European Standard was approved by CEN on 12 April 2021.
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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, 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: Rue de la Science 23, B-1040 Brussels
© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN 16296:2021 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative reference . 5
3 Terms and definitions . 6
4 Quality levels . 6
4.1 Classification. 6
4.2 Choice of quality level . 6
5 Requirements for welded joints . 7
Bibliography . 22
European foreword
This document (EN 16296:2021) 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 November 2021, and conflicting national standards shall
be withdrawn at the latest by November 2021.
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 16296:2012.
In comparison with the previous edition, the following technical modifications have been made:
— the PA polyamide thermoplastic material has been added in Table 1 — Thermoplastic materials;
— in Tables 3 to 8:
— the designation 1AAAA of the quality levels for “cracks” has been deleted to be consistent with
EN 14728:2019;
— the numbers and designations have been updated to be aligned with EN 14728:2019 as the texts
for the quality levels.
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, France, Germany, Greece, Hungary, Iceland, Ireland,
Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of North
Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United
Kingdom.
Introduction
This document is used as a reference in the drafting of application codes and/or other application
standards. It contains a simplified selection of imperfections based on the designations and illustrations
given in EN 14728, Imperfections in thermoplastic welds — Classification.
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 document is to define quality levels based on typical imperfections, which might occur
in normal fabrication. It is applicable for use 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 levels given in this document are intended to provide basic reference data and are not
specifically related to any particular 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.
This document is directly applicable to visual examination of welds or test specimens. The need for
detection is not the subject of this document and this document does not include details of recommended
methods of detection and sizing.
1 Scope
This document specifies quality levels for imperfections in thermoplastics welded joints that have cooled
to ambient temperature and is applicable to material thickness above 2,0 mm.
Three quality levels are specified 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) of the manufactured product.
The quality level necessary are expected to be defined by the application standard or by the fabricator in
conjunction with the user and/or other parties concerned. The level is expected to be prescribed before
the start of production, preferably at the enquiry or order stage.
This document applies to the following thermoplastic materials in Table 1:
Table 1 — Thermoplastic materials
Abbreviation Material description
ABS Acrylonitrile-butadiene-styrene plastic
ECTFE Ethylene-chlorotrifluoroethylene copolymer
FEP Fluorinated ethylene propylene
PA-U Unplasticized polyamide
PB Polybutylene
PE Polyethylene
PFA Perfluoroalkoxy
PP-B Polypropylene block copolymer
PP-H Polypropylene homopolymer
PP-R Polypropylene random copolymer
PVC-C Chlorinated polyvinyl chloride
PVC-U Unplasticized polyvinyl chloride (rigid PVC)
PVDF Polyvinylidene fluoride
and to the following welding processes:
— heated tool welding;
— electrofusion socket welding;
— hot gas welding using filler rod only;
— extrusion welding;
— solvent welding of pipes.
2 Normative reference
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at https://www.electropedia.org/
— ISO Online browsing platform: available at https://www.iso.org/obp
3.1
quality level
description of the qualities of a weld on the basis of type, size and number or frequency 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 quality 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 Intermediate
D Moderate
The purpose of this document is to define quality levels based on typical imperfections, which might occur
in normal fabrications and are classified in EN 14728 [1]. 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 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 pressure pipe systems, it is recommended that at least level B be chosen.
For specific applications, some requirements more stringent than level B might need to be prescribed and
shall be defined between the contracting parties as quality level A.
4.2 Choice of quality level
For the choice of the quality level, the following factors, among others, shall be taken into account:
— mechanical 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;
— design considerations.
Economic factors are also important and should include not only the cost of welding but also the cost of
inspection, test and repair.
5 Requirements for welded joints
Although this document 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 dimensions. However, their detection and evaluation
could 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.
The indication provided by non-destructive testing should not be used directly for the evaluation of
quality levels. Therefore, it needs to be supplemented by requirements for examinations, inspection and
testing.
The requirements for the quality levels in Table 2 (B, C and D) are listed as follows:
— heated tool butt welds: Table 3;
— heated tool socket welds: Table 4;
— electrofusion socket welds: Table 5;
— hot gas welds: Table 6;
— extrusion welds: Table 7;
— solvent socket welds: Table 8.
Different types of imperfection occurring simultaneously at any cross-section of the joint need special
consideration.
Any two adjacent imperfections separated by a distance less than the major dimension of the smaller
imperfection shall be considered as a single imperfection.
In certain circumstances, it is necessary to machine the completed weld. In this case, the weld shall be
examined both before and after machining.
Table 3 — Definition of quality levels for heated tool butt welds
Number Designations Level B Level C Level D
2BAAA Gas cavity Isolated cavities Permissible if Permissible if
permissible if diameter of diameter of
diameter ≤ 5 % largest largest
of wall thickness cavity ≤ 10 % of cavity ≤ 15 % of
wall thickness wall thickness
2CAAI Shrinkage cavity Isolated cavities Permissible if Permissible if
permissible if diameter of diameter of
diameter ≤ 5 % largest largest
of wall thickness cavity ≤ 10 % of cavity ≤ 15 % of
wall thickness wall thickness
2MAAA Surface bubble Permissible if, Permissible if, Permissible if,
when the weld when the weld when the weld
bead is removed, bead is bead is
there is no removed, there removed, there
evidence of gas is no evidence is no evidence of
cavities at the of gas cavities gas cavities at
weld interface at the weld the weld
interface interface
3AAAA Particulate inclusion Isolated and/or Isolated and/or Isolated and/or
multiple multiple multiple
inclusions inclusions inclusions
permissible if permissible if permissible if
sum of maximum sum of sum of
dimensions ≤ 5 maximum maximum
% of wall dimensions ≤ 10 dimensions ≤ 15
thickness % of wall % of wall
thickness thickness
3JAAI Parent material inclusion Not permissible Not permissible Not permissible
3KAAA Degraded polymer Not permissible Not permissible Not permissible
4BAAA Lack of fusion Not permissible Not
...
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