SIST EN ISO 9967:2016

SLOVENSKI STANDARD
SIST EN ISO 9967:2016
01-april-2016
1DGRPHãþD
SIST EN ISO 9967:2008
3ODVWRPHUQHFHYL'RORþDQMHUD]PHUMDOH]HQMD,62
Thermoplastics pipes - Determination of creep ratio (ISO 9967:2016)
Thermoplastische Rohre - Bestimmung des Verformungsverhaltens (ISO 9967:2016)
Tubes en matières thermoplastiques - Détermination du taux de fluage (ISO 9967:2016)
Ta slovenski standard je istoveten z: EN ISO 9967:2016
ICS:
23.040.20 Cevi iz polimernih materialov Plastics pipes
SIST EN ISO 9967:2016 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 9967:2016

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SIST EN ISO 9967:2016


EN ISO 9967
EUROPEAN STANDARD

NORME EUROPÉENNE

January 2016
EUROPÄISCHE NORM
ICS 23.040.20 Supersedes EN ISO 9967:2007
English Version

Thermoplastics pipes - Determination of creep ratio (ISO
9967:2016)
Tubes en matières thermoplastiques - Détermination Thermoplastische Rohre - Bestimmung des
du taux de fluage (ISO 9967:2016) Verformungsverhaltens (ISO 9967:2016)
This European Standard was approved by CEN on 7 November 2015.

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, 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
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9967:2016 E
worldwide for CEN national Members.

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SIST EN ISO 9967:2016
EN ISO 9967:2016 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 9967:2016
EN ISO 9967:2016 (E)
European foreword
This document (EN ISO 9967:2016) has been prepared by Technical Committee ISO/TC 138 "Plastics
pipes, fittings and valves for the transport of fluids" in collaboration with Technical Committee
CEN/TC 155 “Plastics piping systems and ducting systems” the secretariat of which is held by NEN.
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 July 2016, and conflicting national standards shall be
withdrawn at the latest by July 2016.
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 not be held responsible for identifying any or all such patent
rights.
This document supersedes EN ISO 9967:2007.
This document has been prepared under a mandate given to CEN by the European Commission and the
European Free Trade Association.
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, 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.
Endorsement notice
The text of ISO 9967:2016 has been approved by CEN as EN ISO 9967:2016 without any modification.
3

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SIST EN ISO 9967:2016

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SIST EN ISO 9967:2016
INTERNATIONAL ISO
STANDARD 9967
Third edition
2016-01-15
Thermoplastics pipes —
Determination of creep ratio
Tubes en matières thermoplastiques — Détermination du taux de
fluage
Reference number
ISO 9967:2016(E)
©
ISO 2016

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SIST EN ISO 9967:2016
ISO 9967:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

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SIST EN ISO 9967:2016
ISO 9967:2016(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Symbols . 1
4 Principle . 2
5 Apparatus . 2
6 Test pieces . 3
6.1 Marking and number of test pieces . 3
6.2 Length of test pieces . 3
6.3 Inside diameter of test piece(s) . 4
6.4 Age of test pieces . 4
7 Conditioning . 5
8 Test procedure . 5
9 Determination of the creep ratio . 6
10 Test report . 9
Annex A (informative) Creep in thermoplastics material .10
Bibliography .12
© ISO 2016 – All rights reserved iii

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SIST EN ISO 9967:2016
ISO 9967:2016(E)

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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is 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.
This third edition cancels and replaces the second edition (ISO 9967:2007), which has been
technically revised.
iv © ISO 2016 – All rights reserved

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SIST EN ISO 9967:2016
ISO 9967:2016(E)

Introduction
Experience shows that when a pipe is installed in the soil in accordance with an appropriate code of
practice an increase in deflection may be observed. Depending on the soil and installation conditions
this period will vary but normally not exceed two years.
Therefore, the two-year creep ratio as determined in accordance with this International Standard is
intended for use when long-term static calculations are carried out.
The theory of creep in thermoplastics materials is briefly explained in Annex A.
For experiments, the test can be carried out based on other ages of the test pieces, other test
temperatures and/or other test durations.
© ISO 2016 – All rights reserved v

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SIST EN ISO 9967:2016

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SIST EN ISO 9967:2016
INTERNATIONAL STANDARD ISO 9967:2016(E)
Thermoplastics pipes — Determination of creep ratio
1 Scope
This International Standard specifies a method for determining the creep ratio of thermoplastics pipes
having a circular cross-section.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 3126, Plastics piping systems — Plastics components — Determination of dimensions
3 Symbols
Unit
d nominal diameter of pipe mm
n
d inside diameter of test piece of pipe mm
i
F loading force kN
F pre-load force N
0
p pitch mm
L length of test piece mm
y measured initial deflection mm
0
Y calculated deflection at time t mm
t
Y extrapolated two-year deflection mm
2
δ vertical deflection used to determine the loading force mm
B theoretical deflection, at t = 1 h mm
M gradient coefficient
N number of points on the deflection curve used for the linear regression
R correlation coefficient
t time h
x log(t)
y measured total deflection mm
γ creep ratio
© ISO 2016 – All rights reserved 1

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SIST EN ISO 9967:2016
ISO 9967:2016(E)

2
S stiffness kN/m
2
E modulus of elasticity of the material kN/m
3
I moment of inertia m
D mean diameter of the test ring m
4 Principle
A cut length of pipe is placed between two parallel flat horizontal plates and a constant compressive
force is applied for 1 008 h (42 days).
The deflection of the pipe is recorded at specified intervals so as to prepare a plot of pipe deflection
against time. The linearity of the data are analysed and the creep ratio is calculated as the ratio between
the two years’ extrapolated deflection value and the measured 6 min (0,1 h) deflection.
NOTE It is assumed that the test temperature, as appropriate (see 8.1), is set by the referring standard.
5 Apparatus
5.1 Compressive loading machine, capable of applying via plates (5.2) and maintaining to with a
precision of ± 1 % both the applicable pre-load force, F (see 8.4), and the necessary loading force, F
0
(see 8.5), on the pipe.
The force may be applied either directly or indirectly, e.g. by use of a lever arm arrangement.
5.2 Two plates, through which the compressive force can be applied to the test piece. The plates shall
be flat, smooth and clean and shall not deform during the test to an extent that would affect the results.
The length of each plate shall be at least equal to the length of the test piece. The width of each plate
shall be not less than the maximum width of the contact surface with the test piece while under
load plus 25 mm.
5.3 Dimensional measuring devices, capable of determining:
— individual values for the length of a test piece (see 6.2) to with an accuracy of ± 1 mm;
— the inside diameter of a test piece to with an accuracy of ± 0,1 mm or ± 0,2 % d , whichever is the
i
greater;
— the change in inside diameter of a test piece in the direction of loading with an accuracy of 0,1 mm
or 0,1 % of the deflection, whichever is the greater.
The change in inside diameter may be measured inside the pipe or be
...