Thermoplastics pipes and fittings - Vicat softening temperature: General test method and test conditions for Vinyl chloride - based (PVC-U, PVC-C, PVC-Hi) and Acryl nitrile - based (ABS, ASA) pipes and fittings (ISO/DIS 2507:2025)

The method specified is based on determining the temperature at which a standard indenter, under a force of 50 N ± 1 N, penetrates 1 mm into the surface of a test piece cut from the wall of a pipe or fitting while the temperature is raised at a constant rate. Is applicable only to thermoplastics materials for which it is possible to measure the temperature at which the rate of softening becomes rapid. Is based on ISO 306:1994 which, however, applies to materials in the form of sheets.

Rohre und Formstücke aus Thermoplasten - Vicat-Erweichungstemperatur: Allgemeines Prüfverfahren und Prüfbedingungen für Rohre und Formstücke auf Poly(vinylchlorid)- (PVC-U, PVC-C, PVC-Hi) und auf Acrylnitrilbasis (ABS, ASA) (ISO/FDIS 2507:2025)

Dieses Dokument legt ein spezifisches Verfahren zur Bestimmung der Vicat-Erweichungstemperatur (VST) von Rohren und Formstücken aus Thermoplasten fest. Es enthält eine Anpassung des Verfahrens B 50 von ISO 306:2022, in der eine Last von 50 N und eine Heizrate von 50 °C/h angewendet wird, sowie das Verfahren zur Herstellung von Probekörpern.
Es enthält die besonderen Prüfbedingungen für die Bestimmung der Vicat-Erweichungstemperatur (VST) von Rohren und Formstücken aus weichmacherfreiem Poly(vinylchlorid) (PVC-U) oder chloriertem Poly(vinylchlorid) (PVC-C), von Rohren aus hochschlagzähem Poly(vinylchlorid) (PVC-HI) sowie von Rohren und Formstücken aus Acrylnitril-Butadien-Styrol (ABS) und Acrylnitril-Styrol-Acrylester (ASA).
Dieses Dokument kann auch auf Rohre und Formstücke aus anderen Werkstoffen (z. B. PE-UHMW) angewendet werden.

Tubes et raccords en matières thermoplastiques - Température de ramollissement Vicat: Méthode d'essai générale et conditions d’essai pour les tubes et raccords à base de chlorure de vinyle (PVC-U, PVC-C, PVC-Hi) et à base d'acryl nitrile (ABS, ASA) (ISO/FDIS 2507:2025)

Plastomerne cevi in fitingi - Temperatura zmehčišča po Vicatu: Splošna preskusna metoda in preskusni pogoji za cevi in fitinge na osnovi vinilklorida (PVC-U, PVC-C, PVC-Hi) in akrilonitrila (ABS, ASA) (ISO/FDIS 2507:2025)

General Information

Status
Not Published
Public Enquiry End Date
19-May-2025
Current Stage
5020 - Formal vote (FV) (Adopted Project)
Start Date
27-Oct-2025
Due Date
15-Dec-2025
Completion Date
28-Oct-2025

Relations

Effective Date
21-Feb-2024
Effective Date
21-Feb-2024
Effective Date
21-Feb-2024

Overview

kSIST FprEN ISO 2507:2025 is a forthcoming international standard establishing a general test method and precise conditions for determining the Vicat softening temperature (VST) of thermoplastic pipes and fittings. This standard specifically addresses vinyl chloride-based materials-including unplasticized poly(vinyl chloride) (PVC-U), chlorinated poly(vinyl chloride) (PVC-C), and high-impact poly(vinyl chloride) (PVC-Hi)-as well as acrylonitrile-based products such as acrylonitrile/butadiene/styrene (ABS) and acrylonitrile/styrene/acrylic ester (ASA). Developed under the International Organization for Standardization (ISO) and the European Committee for Standardization (CEN), it combines previously separate parts into a comprehensive document, harmonizing test procedures based on the latest revisions of ISO 306.

The standard delineates the methodology for measuring the temperature at which a thermoplastic material softens under a specific load, indicated by a 1 mm penetration of a standardized indenter during controlled heating. This standard is essential for manufacturers, quality controllers, and researchers working with thermoplastic piping systems to ensure reliable performance and compliance with industrial specifications.

Key Topics

  • Scope and Materials
    Applies to thermoplastic pipes and fittings made from PVC-U, PVC-C, PVC-Hi, ABS, and ASA. It excludes crystalline or semi-crystalline polymers. The focus is on materials suited for assessing rapid softening rates through the Vicat softening temperature test.

  • Vicat Softening Temperature (VST)
    Defines VST as the temperature at which a flat-ended indenter penetrates 1 mm into the test specimen under a load of 50 N ± 1 N while the temperature rises steadily at 50 °C per hour ± 5 °C. This temperature reflects the material’s transition from rigid to softened state.

  • Test Specimen Preparation
    Detailed guidelines on extracting test specimens from the walls of pipes and fittings to ensure reproducible and representative results.

  • Apparatus Requirements
    Specifies equipment needed, including:

    • Standard indenters and penetration devices
    • Heating ovens with air circulation to maintain uniform temperature rise
    • Accurate temperature-measuring instruments such as thermocouples or platinum resistance sensors
    • Weights to apply specified load
  • Test Procedure
    Describes conditioning of specimens, especially critical for acrylonitrile-based materials, and the stepwise procedure for conducting the Vicat softening test and recording results.

  • Normative References
    Incorporates related ISO and IEC standards such as ISO 306:2022 (general VST methods), ISO 291 (standard atmospheres for conditioning), and IEC thermocouple and temperature sensor specifications.

  • Informative Annexes
    Provide basic specifications for each thermoplastic material type covered by the standard, facilitating conformance verification and comparison.

Applications

  • Quality Control of Thermoplastic Pipes and Fittings
    Ensures that vinyl chloride and acrylonitrile-based pipes meet critical thermal performance criteria for intended applications, helping manufacturers maintain consistent product quality.

  • Material Selection and Design
    Assists engineers and product developers in selecting appropriate pipe materials based on softening temperature characteristics to guarantee safe use under operational temperature ranges.

  • Regulatory Compliance and Standardization
    Facilitates compliance with national and international regulations where Vicat softening temperature is a key performance metric, supporting market acceptance and certification processes.

  • Research and Development
    Enables precise thermal characterization for new thermoplastic formulations or enhanced compounds designed for improved heat resistance.

Related Standards

  • ISO 306:2022 – Thermoplastics materials - Determination of Vicat softening temperature (general method for sheet materials). ISO 2507 adapts this method specifically for pipes and fittings.

  • ISO 291 – Plastics - Standard atmospheres for conditioning and testing ensures environmental consistency during tests.

  • ISO 472 – Plastics - Vocabulary provides definitions of relevant terminology used in ISO 2507.

  • IEC 60584-1 and IEC 60584-3 – Thermocouples specifications and tolerances essential for calibration of temperature measuring devices.

  • IEC 60751 – Industrial platinum resistance thermometers and temperature sensors-used for accurate temperature monitoring in test setups.


Keywords: Vicat softening temperature, thermoplastic pipes, PVC-U, PVC-C, PVC-Hi, ABS, ASA, test method, ISO 2507, pipe fittings, thermal properties, plastic materials testing, standardized test, quality control, material performance, polymer softening temperature.

Draft

oSIST prEN ISO 2507:2025

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Frequently Asked Questions

kSIST FprEN ISO 2507:2025 is a draft published by the Slovenian Institute for Standardization (SIST). Its full title is "Thermoplastics pipes and fittings - Vicat softening temperature: General test method and test conditions for Vinyl chloride - based (PVC-U, PVC-C, PVC-Hi) and Acryl nitrile - based (ABS, ASA) pipes and fittings (ISO/DIS 2507:2025)". This standard covers: The method specified is based on determining the temperature at which a standard indenter, under a force of 50 N ± 1 N, penetrates 1 mm into the surface of a test piece cut from the wall of a pipe or fitting while the temperature is raised at a constant rate. Is applicable only to thermoplastics materials for which it is possible to measure the temperature at which the rate of softening becomes rapid. Is based on ISO 306:1994 which, however, applies to materials in the form of sheets.

The method specified is based on determining the temperature at which a standard indenter, under a force of 50 N ± 1 N, penetrates 1 mm into the surface of a test piece cut from the wall of a pipe or fitting while the temperature is raised at a constant rate. Is applicable only to thermoplastics materials for which it is possible to measure the temperature at which the rate of softening becomes rapid. Is based on ISO 306:1994 which, however, applies to materials in the form of sheets.

kSIST FprEN ISO 2507:2025 is classified under the following ICS (International Classification for Standards) categories: 23.040.20 - Plastics pipes; 23.040.45 - Plastics fittings. The ICS classification helps identify the subject area and facilitates finding related standards.

kSIST FprEN ISO 2507:2025 has the following relationships with other standards: It is inter standard links to SIST EN ISO 2507-2:2018, SIST EN ISO 2507-1:2018, SIST EN ISO 2507-3:2018. Understanding these relationships helps ensure you are using the most current and applicable version of the standard.

kSIST FprEN ISO 2507:2025 is available in PDF format for immediate download after purchase. The document can be added to your cart and obtained through the secure checkout process. Digital delivery ensures instant access to the complete standard document.

Standards Content (Sample)


SLOVENSKI STANDARD
oSIST prEN ISO 2507:2025
01-maj-2025
Plastomerne cevi in fitingi - Temperatura zmehčišča po Vicatu: Splošna preskusna
metoda in preskusni pogoji za cevi in fitinge na osnovi vinilklorida (PVC-U, PVC-C,
PVC-Hi) in akrilonitrila (ABS, ASA) (ISO/DIS 2507:2025)
Thermoplastics pipes and fittings - Vicat softening temperature: General test method and
test conditions for Vinyl chloride - based (PVC-U, PVC-C, PVC-Hi) and Acryl nitrile -
based (ABS, ASA) pipes and fittings (ISO/DIS 2507:2025)
Rohre und Formstücke aus Thermoplasten - Vicat-Erweichungstemperatur: Allgemeines
Prüfverfahren und Prüfbedingungen für Rohre und Formstücke auf Poly(vinylchlorid)-
(PVC-U, PVC-C, PVC-Hi) und auf Acrylnitrilbasis (ABS, ASA) (ISO/DIS 2507:2025)
Tubes et raccords en matières thermoplastiques - Température de ramollissement Vicat:
Méthode d'essai générale et conditions d’essai pour les tubes et raccords à base de
chlorure de vinyle (PVC-U, PVC-C, PVC-Hi) et à base d'acryl nitrile (ABS, ASA) (ISO/DIS
2507:2025)
Ta slovenski standard je istoveten z: prEN ISO 2507
ICS:
23.040.20 Cevi iz polimernih materialov Plastics pipes
23.040.45 Fitingi iz polimernih Plastics fittings
materialov
oSIST prEN ISO 2507:2025 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

oSIST prEN ISO 2507:2025
oSIST prEN ISO 2507:2025
DRAFT
International
Standard
ISO/DIS 2507
ISO/TC 138/SC 5
Thermoplastics pipes and fittings —
Secretariat: NEN
Vicat softening temperature:
Voting begins on:
General test method and test
2025-02-25
conditions for Vinyl chloride - based
Voting terminates on:
(PVC-U, PVC-C, PVC-Hi) and Acryl
2025-05-20
nitrile - based (ABS, ASA) pipes and
fittings
Tubes et raccords en matières thermoplastiques — Température
de ramollissement Vicat : Méthode d'essai générale et conditions
d’essai pour les tubes et raccords à base de chlorure de vinyle
(PVC-U, PVC-C, PVC-Hi) et à base d'acryl nitrile (ABS, ASA)
ICS: 23.040.20; 23.040.45
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS.
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Reference number
ISO/DIS 2507:2025(en)
oSIST prEN ISO 2507:2025
DRAFT
ISO/DIS 2507:2025(en)
International
Standard
ISO/DIS 2507
ISO/TC 138/SC 5
Thermoplastics pipes and fittings —
Secretariat: NEN
Vicat softening temperature:
Voting begins on:
General test method and test
conditions for Vinyl chloride - based
Voting terminates on:
(PVC-U, PVC-C, PVC-Hi) and Acryl
nitrile - based (ABS, ASA) pipes and
fittings
Tubes et raccords en matières thermoplastiques — Température
de ramollissement Vicat : Méthode d'essai générale et conditions
d’essai pour les tubes et raccords à base de chlorure de vinyle
(PVC-U, PVC-C, PVC-Hi) et à base d'acryl nitrile (ABS, ASA)
ICS: 23.040.20; 23.040.45
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2025
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
ISO/CEN PARALLEL PROCESSING
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
BE CONSIDERED IN THE LIGHT OF THEIR
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
or ISO’s member body in the country of the requester.
NATIONAL REGULATIONS.
ISO copyright office
RECIPIENTS OF THIS DRAFT ARE INVITED
CP 401 • Ch. de Blandonnet 8
TO SUBMIT, WITH THEIR COMMENTS,
CH-1214 Vernier, Geneva
NOTIFICATION OF ANY RELEVANT PATENT
Phone: +41 22 749 01 11
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION.
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland Reference number
ISO/DIS 2507:2025(en)
ii
oSIST prEN ISO 2507:2025
ISO/DIS 2507:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions, . 1
4 Principle . 2
5 Apparatus . 2
5.1 Means of producing penetration .2
5.2 Indenter . . .2
5.3 Heating equipment .3
5.4 Weights .3
5.5 Temperature-measuring device .3
5.6 Penetration-measuring device .3
5.7 Micrometers and gauges .4
5.8 Oven with air circulation .4
6 Test specimens . 5
6.1 Specimen preparation from pipes .5
6.2 Specimen preparation from fittings .7
6.3 Number of test specimen .7
7 Conditioning . 7
7.1 General .7
7.2 Conditioning for specimens from acrylonitrile-based (ABS, ASA) pipes and fittings .7
8 Procedure . 7
9 Test Report . 8
Annex A (informative) Unplasticized poly(vinyl chloride) (PVC-U) pipes and fittings – Basic
specification . 9
Annex B (informative) Chlorinated poly(vinyl chloride) (PVC-C) pipes and fittings – Basic
specification .10
Annex C (informative) High impact resistant poly (vinyl chloride) (PVC-HI) pipes – Basic
specification .11
Annex D (informative) Acrylonitrile/butadiene/styrene (ABS) pipes and fittings – Basic
specification .12
Annex E (informative) Acrylonitrile/styrene/ acrylic ester (ASA) pipes and fittings – Basic
specification .13

iii
oSIST prEN ISO 2507:2025
ISO/DIS 2507:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent
rights identified during the development of the document will be in the Introduction and/or on the ISO list of
patent declarations received (see www.iso.org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 5, General properties of pipes, fittings and valves of plastic materials
and their accessories – Test methods and basic specifications.
ISO 2507:1995 consists of the following parts, under the general title Thermoplastics pipes and fittings – Vicat
softening temperature:
— Part 1: General test method
— Part 2: Test conditions for unplasticized poly(vinyl chloride) (PVC-U) or chlorinated poly(vinyl chloride)
(PVC-C) pipes and fittings and for high impact resistant poly(vinyl chloride) (PVC-HI) pipes.
— Part 3: Test conditions for acrylonitrile/butadiene/styrene (ABS) and acrylonitrile/styrene/ acrylic ester
(ASA) pipes and fittings.
This third edition cancels and replaces all three parts of the first edition (ISO 2507-1:1995; ISO 2507-2:1995;
ISO 2507-3:1995), by merging all parts into one document (ISO 2507:2024) and has been technically revised.
The main changes are as follows:
— The document was modified following edition 6 of ISO 306:2022
— The procedure for test piece preparation from pipes and fittings is described more detailed
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
oSIST prEN ISO 2507:2025
ISO/DIS 2507:2025(en)
Introduction
This International Standard is based on ISO 306.
For convenience of use, it has been considered preferable to draw up a complete document for use in
determining the Vicat softening temperature of thermoplastics pipes and fittings. For further details,
reference to ISO 306 is recommended.
Please note, however, that ISO 306 is applicable to materials in the form of sheets, whereas this International
Standard is applicable to products in the form of pipes and fittings.
ISO 2507 gives the general conditions under which the Vicat softening temperature of pipes and fittings is
determined and provides the particular requirements for conducting tests on pipes and fittings of various
materials.
The basic specifications for various materials are given in the informative annexes.

v
oSIST prEN ISO 2507:2025
oSIST prEN ISO 2507:2025
DRAFT International Standard ISO/DIS 2507:2025(en)
Thermoplastics pipes and fittings — Vicat softening
temperature: General test method and test conditions for
Vinyl chloride - based (PVC-U, PVC-C, PVC-Hi) and Acryl nitrile
- based (ABS, ASA) pipes and fittings
1 Scope
ISO 2507 specifies a general method for determining the Vicat softening temperature (VST) of thermoplastics
pipes and fittings. It includes the adaption of method B 50 of ISO 306: 2022 using a force of 50 N and a
heating rate of 50 °C/h.
It includes the particular test conditions for determining the Vicat softening temperature (VST) of
unplasticized poly(vinylchloride) (PVC-U) or chlorinated poly(vinylchloride) (PVC-C) pipes and fittings, for
high impact resistance poly(vinylchloride) (PVC-HI) pipes and for acrylonitrile/butadiene/styrene (ABS)
and acrylonitrile/styrene/acrylic ester (ASA) pipes and fittings.
It also gives, for information, the corresponding base specifications.
It is not applicable to crystalline or semi-crystalline polymers.
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.
ISO 291, Plastics — Standard atmospheres for conditioning and testing
ISO 306:2022, Plastics — Thermoplastic materials — Determination of Vicat softening temperature (VST)
ISO 472, Plastics — Vocabulary
ISO 16012, Plastics — Determination of linear dimensions of test specimens
IEC 60584-1, Thermocouples -Part 1: EMF specifications and tolerances
IEC 60584-3, Thermocouples - Part 3: Extension and compensating cables - Tolerances and identification system
IEC 60751, Industrial platinum resistance thermometers and platinum temperature sensors
3 Terms and definitions,
For the purposes of this document, the terms and definitions given in ISO 472 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www
...

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