oSIST prEN ISO 10928:2025
(Main)Plastics piping systems - Glass-reinforced thermosetting plastics (GRP) pipes and fittings - Methods for regression analysis and their use (ISO 10928:2024)
Plastics piping systems - Glass-reinforced thermosetting plastics (GRP) pipes and fittings - Methods for regression analysis and their use (ISO 10928:2024)
This document specifies procedures suitable for the analysis of data which, when converted into logarithms
of the values, have either a normal or a skewed distribution. It is intended for use with test methods and
referring standards for glass-reinforced thermosetting plastics (GRP) pipes or fittings for the analysis of
properties as a function of time. However, it can also be used for the analysis of other data.
Two methods are specified, which are used depending on the nature of the data. Extrapolation using these
techniques typically extends a trend from data gathered over a period of approximately 10 000 h to a
prediction of the property at 50 years, which is the typical maximum extrapolation time.
This document only addresses the analysis of data. The test procedures for collecting the data, the number of samples required and the time period over which data are collected are covered by the referring standards and/ or test methods. Clause 6 discusses how the data analysis methods are applied to product testing and design.
Kunststoff-Rohrleitungssysteme - Rohre und Formstücke aus glasfaserverstärkten Kunststoffen (GFK) - Verfahren zur Regressionsanalyse und deren Anwendung (ISO 10928:2024)
Systèmes de canalisations en matières plastiques - Tubes et raccords plastiques thermodurcissables renforcés de verre (PRV) - Méthodes pour une analyse de régression et leurs utilisations (ISO 10928:2024)
Cevni sistemi iz polimernih materialov - Cevi in fitingi iz duromernih materialov, ojačenih s steklenimi vlakni (GRP) - Metode za regresijsko analizo in njihova uporaba (ISO 10928:2024)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-januar-2025
Cevni sistemi iz polimernih materialov - Cevi in fitingi iz duromernih materialov,
ojačenih s steklenimi vlakni (GRP) - Metode za regresijsko analizo in njihova
uporaba (ISO 10928:2024)
Plastics piping systems - Glass-reinforced thermosetting plastics (GRP) pipes and fittings
- Methods for regression analysis and their use (ISO 10928:2024)
Kunststoff-Rohrleitungssysteme - Rohre und Formstücke aus glasfaserverstärkten
Kunststoffen (GFK) - Verfahren zur Regressionsanalyse und deren Anwendung (ISO
10928:2024)
Systèmes de canalisations en matières plastiques - Tubes et raccords plastiques
thermodurcissables renforcés de verre (PRV) - Méthodes pour une analyse de
régression et leurs utilisations (ISO 10928:2024)
Ta slovenski standard je istoveten z: prEN ISO 10928
ICS:
23.040.20 Cevi iz polimernih materialov Plastics pipes
23.040.45 Fitingi iz polimernih Plastics fittings
materialov
83.120 Ojačani polimeri Reinforced plastics
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
International
Standard
ISO 10928
Fourth edition
Plastics piping systems — Glass-
2024-03
reinforced thermosetting plastics
(GRP) pipes and fittings — Methods
for regression analysis and their use
Systèmes de canalisations en matières plastiques — Tubes et
raccords plastiques thermodurcissables renforcés de verre (PRV)
— Méthodes pour une analyse de régression et leurs utilisations
Reference number
ISO 10928:2024(en) © ISO 2024
ISO 10928:2024(en)
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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Published in Switzerland
ii
ISO 10928:2024(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Procedures for determining the linear relationships — Methods A and B . 1
5.1 Procedures common to methods A and B .1
5.2 Method A — Covariance method.2
5.2.1 General .2
5.2.2 Suitability of data . .3
5.2.3 Functional relationships . .3
5.2.4 Calculation of variances .4
5.2.5 Check for the suitability of data for extrapolation .4
5.2.6 Validation of statistical procedures by an example calculation .5
5.3 Method B — Regression with time as the independent variable .8
5.3.1 General .8
5.3.2 Suitability of data . .9
5.3.3 Functional relationships . . .9
5.3.4 Check for the suitability of data for extrapolation .9
5.3.5 Validation of statistical procedures by an example calculation .9
6 Application of methods to product design and testing .11
6.1 General .11
6.2 Product design .11
6.3 Comparison to a specified value .11
6.4 Declaration of a long-term value .11
Annex A (informative) Second-order polynomial relationships .12
Annex B (normative) Calculation of lower confidence and prediction limits for method A .16
Bibliography . 19
iii
ISO 10928:2024(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 138, Plastics pipes, fittings and valves for the
transport of fluids, Subcommittee SC 6, Reinforced plastics pipes and fittings for all applications.
This fourth edition cancels and replaces the third edition (ISO 10928:2016), which has been technically
revised.
The main changes are as follows:
— Annex B, “Non-linear relationships”, has been removed due to its complexity and highly specialized and
limited application;
— Formula (B.3) [Formula (C.3) in ISO 10928:2016] has been corrected to include a factor 2 before Bx
L.
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
ISO 10928:2024(en)
Introduction
This document describes the procedures intended for analysing the regression of test data, usually with
respect to time, and the use of the results in the design and assessment of conformity with performance
requirements. Its applicability is limited to use with data obtained from tests carried out on samples.
Referring standards require estimates to be made of the long-term properties of the pipe for such parameters
as circumferential tensile strength, long-term ring deflection, strain corrosion and creep or relaxation
stiffness.
A range of statistical techniques that can be used to analyse the test data produced by destructive tests were
investigated in the preparation of this document. Many of these simple techniques require the logarithms of
the data to:
a) be normally distributed;
b) produce a regression line having a negative slope; and
c) have a sufficiently high regression correlation (see Table 1).
Analysis of data from several tests showed that in the destructive test context, while conditions b) and c)
can be satisfied, there is often a skew to the distribution and hence condition a) is not satisfied. Further
investigation into techniques that can handle skewed distributions resulted in the adoption of the covariance
method (method A, see 5.2) for the analysis of such data within this document.
The results from non-destructive tests, such as long-term creep or relaxation stiffness, often satisfy all three
conditions. Therefore, a simpler procedure, using time as the independent variable (method B, see 5.3), can
also be used in accordance with this document.
These two analysis procedures (method A and method B) are limited to analysis methods specified in ISO
product standards or test methods. Other analysis procedures can be useful for the extrapolation and
prediction of long-term behaviour of some properties of glass-reinforced thermosetting plastics (GRP)
piping products. For example, a second-order polynomial analysis is sometimes useful in the extrapolation
of creep and relaxation data. This is particularly the case for analysing shorter term data, where the shape
of the creep or relaxation curve can deviate considerably from linear. A second-order polynomial analysis is
included in Annex A.
v
International Standard ISO 10928:2024(en)
Plastics piping systems — Glass-reinforced thermosetting
plastics (GRP) pipes and fittings — Methods for regression
analysis and their use
1 Scope
This document specifies procedures suitable for the analysis of data which, when converted into logarithms
of the values, have either a normal or a skewed distribution. It is intended for use with test methods and
referring standards for glass-reinforced thermosetting plastics (GRP) pipes or fittings for the analysis of
properties as a function of time. However, it can also be used for the analysis of other data.
Two methods are specified, which are used depending on the nature of the data. Extrapolation using these
techniques typically extends a trend from data gathered over a period of approximately 10 000 h to a
prediction of the property at 50 years, which is the typical maximum extrapolation time.
This document only addresses the analysis of data. The test procedures for collecting the data, the number of
samples required and the time period over which data are collected are covered by the referring standards and/
or test methods. Cl
...
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