EN ISO 899-2:2024

Plastics - Determination of creep behaviour - Part 2: Flexural creep by three-point loading (ISO 899-2:2024)

This document specifies a method for determining the flexural creep of plastics in the form of standard test specimens under specified conditions such as those of pre-treatment, temperature and humidity. It is only applicable to a simple freely supported beam loaded at mid-span (three-point-loading test).
 The method is suitable for use with rigid and semi-rigid non-reinforced, filled and fibre-reinforced plastics materials (see ISO 472 for definitions) test specimens moulded directly or machined from sheets or moulded articles.
NOTE            The method can be unsuitable for certain fibre-reinforced materials due to differences in fibre orientation
The method is intended to provide data for engineering-design, quality control, research and development purposes.
The method might not be applicable for determining the flexural creep of rigid cellular plastics (attention is drawn in this respect to ISO 1209-1 and ISO 1209-2).

Kunststoffe - Bestimmung des Kriechverhaltens - Teil 2: Zeitstand-Biegeversuch bei Dreipunkt-Belastung (ISO 899-2:2024)

1.1   Dieses Dokument legt ein Verfahren zur Bestimmung des Biege-Kriech-Verhaltens von Kunststoffen in Form von genormten Probekörpern unter festgelegten Bedingungen z. B. von Vorbehandlung, Temperatur und Luftfeuchte fest. Es ist nur auf einen einfachen, frei aufgelegten Biegebalken anwendbar, der in der Mitte belastet ist (Dreipunkt-Biegeversuch).
1.2   Das Verfahren ist geeignet für die Anwendung auf Probekörper aus steifen und halbsteifen unverstärkten, gefüllten und faserverstärkten Kunststoff-Formmassen (Definitionen siehe ISO 472), die entweder direkt gespritzt oder spanend aus Platten oder gespritzten Fertigteilen entnommen wurden.
ANMERKUNG   Das Verfahren kann für bestimmte faserverstärkte Kunststoffe wegen Unterschieden in der Faserorientierung ungeeignet sein.
1.3   Das Verfahren soll Daten für konstruktive Zwecke, Qualitätskontrolle, Forschung und Entwicklung liefern.
1.4   Das Verfahren ist möglicherweise nicht anwendbar für die Bestimmung des Biege-Kriech-Verhaltens von harten Schaumstoffen (in diesem Zusammenhang wird auf ISO 1209 1 und ISO 1209 2 verwiesen).

Plastiques - Détermination du comportement au fluage - Partie 2: Fluage en flexion par mise en charge en trois points (ISO 899-2:2024)

Le présent document spécifie une méthode de détermination du fluage en flexion des plastiques sous forme d’éprouvettes normalisées dans des conditions spécifiées, telles qu’en matière de traitement préalable, de température et d’humidité. Cette méthode s’applique uniquement aux poutres simples, supportées sans contrainte et chargées au milieu de leur portée (méthode de mise en charge en trois points).
Cette méthode est destinée aux éprouvettes en matériaux plastiques rigides et semi-rigides, non renforcés, chargés et renforcés par des fibres (voir l’ISO 472 pour les définitions) moulées directement ou usinées dans des feuilles ou des objets moulés.
NOTE            Cette méthode peut s’avérer inappropriée dans le cas de certaines matières renforcées par des fibres en raison des différences d’orientation de celles-ci.
Cette méthode est proposée pour fournir des données utiles pour la conception en ingénierie, la recherche et le développement.
La présente méthode peut s’avérer inapplicable pour déterminer le fluage en flexion des plastiques alvéolaires rigides (à cet égard, l’attention est attirée sur l’ISO 1209-1 et l’ISO 1209-2).

Polimerni materiali - Ugotavljanje lezenja - 2. del: Lezenje pri tritočkovni obremenitvi (ISO 899-2:2024)

1.1 Ta dokument določa metodo za ugotavljanje upogibnega lezenja polimernih materialov v obliki standardnih preskušancev pod določenimi pogoji, npr. pogoji za predhodno obdelavo, temperaturo in vlago. Uporablja se samo za preprost prosto podprt nosilec, obremenjen na sredini (preskus s tritočkovno obremenitvijo).
1.2 Metoda je primerna za uporabo s preskušanci iz trdih in poltrdih neojačanih polimernih materialov, polnjenih polimernih materialov ter z vlakni ojačanih polimernih materialov (za definicije glej standard ISO 472), ki so neposredno oblikovani oziroma izdelani iz trakov ali oblikovanih predmetov.
OPOMBA: Metoda morda ne bo primerna za nekatere z vlakni ojačane materiale zaradi različne usmerjenosti vlaken.
1.3 Cilj metode je zagotoviti podatke za namene tehničnega načrtovanja, nadzora kakovosti, raziskav in razvoja.
1.4 Metoda morda ne bo primerna za ugotavljanje upogibnega lezenja penjenih polimernih materialov (to je podrobneje zajeto v standardih ISO 1209-1 in ISO 1209-2).

General Information

• Status: Published
• Publication Date: 22-Oct-2024
• ICS: 83.080.01 - Plastics in general
• Technical Committee: CEN/TC 249 - Plastics
• Drafting Committee: CEN/TC 249 - Plastics
• Current Stage: 6060 - Definitive text made available (DAV) - Publishing
• Start Date: 23-Oct-2024
• Completion Date: 23-Oct-2024
• Ref Project: SIST EN ISO 899-2:2024 - Plastics - Determination of creep behaviour - Part 2: Flexural creep by three-point loading (ISO 899-2:2024)

Relations

• Replaces: EN ISO 899-2:2003/A1:2015 - Plastics - Determination of creep behaviour - Part 2: Flexural creep by three-point loading - Amendment 1 (ISO 899-2:2003/Amd 1:2015)
• Effective Date: 19-Jan-2023
• Replaces: EN ISO 899-2:2003 - Plastics - Determination of creep behaviour - Part 2: Flexural creep by three-point loading (ISO 899-2:2003)
• Effective Date: 22-Dec-2021

Overview

EN ISO 899-2:2024 (ISO 899-2:2024) specifies a standardized laboratory method to determine the flexural creep behaviour of plastics using a simple three-point loading (mid-span loaded, freely supported beam) test. The document defines specimen requirements, test atmosphere, loading and deflection measurement practices, result calculation and presentation. It is intended to generate reliable creep data for engineering design, quality control and research.

Key topics and technical requirements

• Test scope and applicability
  • Applies to rigid and semi-rigid non-reinforced, filled and fibre‑reinforced plastics (moulded or machined specimens).
  • May be unsuitable for some fibre‑reinforced materials due to fibre‑orientation effects and for certain rigid cellular plastics (see ISO 1209‑1 and ISO 1209‑2).
• Specimens and conditioning
  • Defines specimen shape and dimensions (aligned with ISO 178-derived definitions), preferred types, and pre‑treatment/conditioning in standard atmospheres (see ISO 291).
• Apparatus and measurement
  • Requires a three‑point loading fixture with defined support spacing and a deflection‑measurement system meeting updated accuracy requirements; extensometer calibration references include ISO 9513 and ISO 16012 for dimensional measurement.
• Procedure
  • Covers preloading, selection of stress levels, loading schedules, time and temperature/humidity control, and optional recovery measurements.
• Data and results
  • Prescribes calculations and presentation for flexural‑creep modulus, flexural‑creep compliance, flexural stress, flexural‑creep strain, time to rupture and creep‑strength limit.
  • Recommends graphical outputs such as creep curves, creep‑modulus/time curves, isochronous stress‑strain curves and three‑dimensional representations.
• Precision and reporting
  • Includes guidance on precision and the required content for a complete test report.

Practical applications

• Produces time‑dependent deformation data for:
  • Structural and mechanical design (long‑term load performance)
  • Material selection and specification for components under sustained bending
  • Quality control and batch verification of plastics and compounded materials
  • Research & development, ageing studies and comparative material testing

Who should use this standard

• Materials engineers, design engineers and R&D laboratories working with thermoplastics, thermosets and reinforced plastics
• Quality control technicians and testing labs performing mechanical property verification
• Standards committees and product certifiers requiring harmonized flexural creep data

Related standards

• ISO 178 (flexural properties)
• ISO 291 (standard atmospheres)
• ISO 472 (vocabulary)
• ISO 9513, ISO 16012 (measurement and calibration)
• ISO 1209‑1 / ISO 1209‑2 (rigid cellular plastics - applicability notes)

Keywords: EN ISO 899-2:2024, ISO 899-2:2024, flexural creep, three-point loading, plastics testing, creep behaviour, flexural‑creep modulus.

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2024
Nadomešča:
SIST EN ISO 899-2:2003/A1:2015
Polimerni materiali - Ugotavljanje lezenja - 2. del: Lezenje pri tritočkovni
obremenitvi (ISO 899-2:2024)
Plastics - Determination of creep behaviour - Part 2: Flexural creep by three-point
loading (ISO 899-2:2024)
Kunststoffe - Bestimmung des Kriechverhaltens - Teil 2: Zeitstand-Biegeversuch bei
Dreipunkt-Belastung (ISO 899-2:2024)
Plastiques - Détermination du comportement au fluage - Partie 2: Fluage en flexion par
mise en charge en trois points (ISO 899-2:2024)
Ta slovenski standard je istoveten z: EN ISO 899-2:2024
ICS:
83.080.01 Polimerni materiali na Plastics in general
splošno
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 899-2
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2024
EUROPÄISCHE NORM
ICS 83.080.01 Supersedes EN ISO 899-2:2003, EN ISO 899-
2:2003/A1:2015
English Version
Plastics - Determination of creep behaviour - Part 2:
Flexural creep by three-point loading (ISO 899-2:2024)
Plastiques - Détermination du comportement au fluage Kunststoffe - Bestimmung des Kriechverhaltens - Teil
- Partie 2: Fluage en flexion par mise en charge en trois 2: Zeitstand-Biegeversuch bei Dreipunkt-Belastung
points (ISO 899-2:2024) (ISO 899-2:2024)
This European Standard was approved by CEN on 18 October 2024.

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, Türkiye 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
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 899-2:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 899-2:2024) has been prepared by Technical Committee ISO/TC 61 "Plastics" in
collaboration with Technical Committee CEN/TC 249 “Plastics” the secretariat of which is held by SIS.
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 April 2025, and conflicting national standards shall be
withdrawn at the latest by April 2025.
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 ISO 899-2:2003.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations 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, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 899-2:2024 has been approved by CEN as EN ISO 899-2:2024 without any modification.

International
Standard
ISO 899-2
Third edition
Plastics — Determination of creep
2024-10
behaviour —
Part 2:
Flexural creep by three-point loading
Plastiques — Détermination du comportement au fluage —
Partie 2: Fluage en flexion par mise en charge en trois points
Reference number
ISO 899-2:2024(en) © ISO 2024
ISO 899-2:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii
ISO 899-2:2024(en)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Apparatus . 3
5 Test specimens . 4
5.1 Shape and dimensions .4
5.2 Preferred specimen type .4
5.3 Other test specimens .5
6 Procedure . 5
6.1 General .5
6.2 Conditioning and test atmosphere.5
6.3 Measurement of test-specimen dimensions and distance between supports .5
6.4 Mounting the test specimens .6
6.5 Selection of stress value .6
6.6 Loading procedure .6
6.6.1 Preloading .6
6.6.2 Loading .6
6.7 Deflection-measurement schedule .6
6.8 Time measurement .7
6.9 Temperature and humidity control .7
6.10 Measurement of recovery rate (optional) .7
7 Expression of results . 7
7.1 Method of calculation .7
7.1.1 Flexural-creep modulus .7
7.1.2 Flexural-creep compliance .7
7.1.3 Flexural stress .8
7.1.4 Flexural-creep strain .8
7.1.5 Time to rupture .8
7.1.6 Creep-strength limit .8
7.2 Presentation of results .9
7.2.1 Creep curves.9
7.2.2 Creep-modulus/time curves .9
7.2.3 lsochronous stress-strain curves .10
7.2.4 Three-dimensional representation .10
7.2.5 Creep-to-rupture curves .10
7.3 Precision . . .11
8 Test report .11
Annex A (informative) Physical-ageing effects on the creep of polymers .12
Bibliography .16

iii
ISO 899-2:2024(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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 61, Plastics, Subcommittee SC 2, Mechanical
behavior, in collaboration with the European Committee for Standardization (CEN) Technical Committee
CEN/TC 249, Plastics, in accordance with the Agreement on technical cooperation between ISO and CEN
(Vienna Agreement).
This third edition cancels and replaces the second edition (ISO 899-2:2003), which has been technically
revised. It also incorporates the Amendment ISO ISO 899-2:2003/Amd. 1:2015.
The main changes are as follows:
— the accuracy requirements for the deflection measurement device have been updated;
— the normative references have been updated;
— the definition of "creep" has been adapted for clarity;
— the definitions for shape and dimensions of test specimens were adapted from ISO 178:2019;
— identified inconsistencies and mistakes have been corrected.
A list of all parts in the ISO 899 series can be found on the ISO website.
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
International Standard ISO 899-2:2024(en)
Plastics — Determination of creep behaviour —
Part 2:
Flexural creep by three-point loading
1 Scope
1.1 This document specifies a method for determining the flexural creep of plastics in the form of standard
test specimens under specified conditions such as those of pre-treatment, temperature and humidity. It is
only applicable to a simple freely supported beam loaded at mid-span (three-point-loading test).
1.2 The method is suitable for use with rigid and semi-rigid non-reinforced, filled and fibre-reinforced
plastics materials (see ISO 472 for definitions) test specimens moulded directly or machined from sheets or
moulded articles.
NOTE The method can be unsuitable for certain fibre-reinforced materials due to differences in fibre orientation.
1.3 The method is intended to provide data for engineering-design, quality control, research and
development purposes.
1.4 The method might not be applicable for determining the flexural creep of rigid cellular plastics
(attention is drawn in this respect to ISO 1209-1 and ISO 1209-2).
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 178, Plastics — Determination of flexural properties
ISO 291, Plastics — Standard atmospheres for conditioning and testing
ISO 472, Plastics — Vocabulary
ISO 9513, Metallic materials — Calibration of extensometer systems used in uniaxial testing
ISO 16012, Plastics — Determination of linear dimensions of test specimens
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 .electropedia .org/

ISO 899-2:2024(en)
3.1
creep
increase in strain with time under constant force, measured from the first moment when the loading of the
specimen started
3.2
load
force applied to the test specimen at mid-span
Note 1 to entry: It is expressed in Newtons
3.3
flexural stress
σ
surface stress in the mid-span section of the test specimen
Note 1 to entry: It is expressed in megapascals.
Note 2 to entry: It is calculated from the relationship given in 7.1.3
3.4
deflection
s
t
distance over which the top or bottom surface of the test specimen at mid-span deviates from its unloaded
original position during flexure
Note 1 to entry: It is expressed in millimetres.
3.5
flexural-creep strain
ε
t
strain at the surface of the test specimen produced by a stress at any given time t during a creep test
Note 1 to entry: It is calculated according to 7.1.4.
Note 2 to entry: It is expressed as a dimensionless ratio or as a percentage.
3.6
flexural-creep modulus
E
t
ratio of flexural stress to flexural-creep strain
Note 1 to entry: It is calculated as in 7.1.1.
Note 2 to entry: It is expressed in megapascals.
3.7
flexural-creep compliance
D
t
ratio of flexural-creep strain to flexural stress
Note 1 to entry: It is calculated as in 7.1.2.
-1
Note 2 to entry: It is expressed in gigapascals
3.8
isochronous stress-strain curve
Cartesian plot of stress versus creep strain, at a specific time after application of the load to the specimen
3.9
time to rupture
period of time the specimen is under full load until rupture

ISO 899-2:2024(en)
3.10
creep-strength limit
initial stress which will just cause rupture (σ ) or will produce a specified strain (σ ) at a specified time t,
B,t ε,t
at a given temperature and relative humidity
Note 1 to entry: It is expressed in megapascals.
3.11
initial distance between specimen supports
span
L
initial distance between lines of contact between test specimen and supports (see Figure 1)
Note 1 to entry: It is expressed in millimetres.
4 Apparatus
4.1 Test rack, comprising a rigid frame with two supports, one for each end of the test specimen, the
distance between the supports being adjustable to (16 ± 1) times the thickness (height) of the specimen (see
Figure 1) for normal specimens, or to greater than 17 times the thickness (height) of the specimen or a fixed
distance (100 mm) for rigid unidirectional-fibre-reinforced test specimens (see 6.3). The test rack shall be
levelled, and sufficient space shall be allowed below the specimen for the specimen to flex under constant
loading at mid-span.
Key
1 applied force, F L initial distance between specimen supports
2 loading edge l specimen length
3 test specimen h specimen thickness
4 support R radius of the loading edge
R radius of the supports
Figure 1 — Characteristics of flexural-creep apparatus
The radius R of the loading edge and the radius R of the supports shall conform to the values given in
1 2
Table 1.
ISO 899-2:2024(en)
Table 1 — Radii of the loading edge and the supports
Values in millimetres
Radius of loading edge Ra
...