SIST EN ISO 9080:2012
(Main)Plastics piping and ducting systems - Determination of the long-term hydrostatic strength of thermoplastics materials in pipe form by extrapolation (ISO 9080:2012)
Plastics piping and ducting systems - Determination of the long-term hydrostatic strength of thermoplastics materials in pipe form by extrapolation (ISO 9080:2012)
This International Standard specifies a method for predicting the long-term hydrostatic strength of thermoplastics materials by statistical extrapolation. The method is applicable to all types of thermoplastics pipe at applicable temperatures. It was developed on the basis of test data from pipe systems.
Kunststoff-Rohrleitungs- und Schutzrohrsysteme - Bestimmung des Zeitstand-Innendruckverhaltens von thermoplastischen Rohrwerkstoffen durch Extrapolation (ISO 9080:2012)
Diese Internationale Norm beschreibt ein Verfahren zur Ermittlung der Zeitstand-Innendruckfestigkeit von thermo¬plastischen Werkstoffen durch statistische Extrapolation.
Das Verfahren gilt bei den vorgesehenen Temperaturen für sämtliche Arten thermoplastischer Rohre. Es wurde auf der Grundlage von Prüfergebnissen für Rohrsysteme entwickelt. Die Maße der zu prüfenden Rohre können in den entsprechenden Produkt-/Systemnormen festgelegt sein.
Systèmes de canalisations et de gaines en matières plastiques - Détermination de la résistance hydrostatique à long terme des matières thermoplastiques sous forme de tubes par extrapolation (ISO 9080:2012)
L'ISO 9080:2012 décrit une méthode d'estimation de la résistance hydrostatique à long terme des matières thermoplastiques à l'aide d'une extrapolation par les statistiques. La méthode peut être utilisée pour tous les types de tubes thermoplastiques aux températures appropriées. Elle a été développée sur la base de données d'essai provenant de systèmes de canalisations.
Cevni in kanalski sistemi iz polimernih materialov - Ugotavljanje dolgotrajne hidrostatične trdnosti termoplastičnih materialov za cevi z metodo ekstrapolacije (ISO 9080:2012)
Ta mednarodni standard določa metodo za predvidevanje dolgotrajne hidrostatične trdnosti termoplastičnih materialov s statistično ekstrapolacijo. Ta metoda se uporablja za vse vrste termoplastičnih cevi pri ustreznih temperaturah. Razvit je bil na osnovi podatkov o preskusu iz cevnih sistemov.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 9080:2012
01-december-2012
1DGRPHãþD
SIST EN ISO 9080:2003
&HYQLLQNDQDOVNLVLVWHPLL]SROLPHUQLKPDWHULDORY8JRWDYOMDQMHGROJRWUDMQH
KLGURVWDWLþQHWUGQRVWLWHUPRSODVWLþQLKPDWHULDORY]DFHYL]PHWRGRHNVWUDSRODFLMH
,62
Plastics piping and ducting systems - Determination of the long-term hydrostatic strength
of thermoplastics materials in pipe form by extrapolation (ISO 9080:2012)
Kunststoff-Rohrleitungs- und Schutzrohrsysteme - Bestimmung des Zeitstand-
Innendruckverhaltens von thermoplastischen Rohrwerkstoffen durch Extrapolation (ISO
9080:2012)
Systèmes de canalisations et de gaines en matières plastiques - Détermination de la
résistance hydrostatique à long terme des matières thermoplastiques sous forme de
tubes par extrapolation (ISO 9080:2012)
Ta slovenski standard je istoveten z: EN ISO 9080:2012
ICS:
23.040.20 Cevi iz polimernih materialov Plastics pipes
SIST EN ISO 9080:2012 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 9080:2012
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SIST EN ISO 9080:2012
EUROPEAN STANDARD
EN ISO 9080
NORME EUROPÉENNE
EUROPÄISCHE NORM
October 2012
ICS 23.040.20 Supersedes EN ISO 9080:2003
English Version
Plastics piping and ducting systems - Determination of the long-
term hydrostatic strength of thermoplastics materials in pipe
form by extrapolation (ISO 9080:2012)
Systèmes de canalisations et de gaines en matières Kunststoff-Rohrleitungs- und Schutzrohrsysteme -
plastiques - Détermination de la résistance hydrostatique à Bestimmung des Zeitstand-Innendruckverhaltens von
long terme des matières thermoplastiques sous forme de thermoplastischen Rohrwerkstoffen durch Extrapolation
tubes par extrapolation (ISO 9080:2012) (ISO 9080:2012)
This European Standard was approved by CEN on 6 October 2012.
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
Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2012 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9080:2012: E
worldwide for CEN national Members.
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SIST EN ISO 9080:2012
EN ISO 9080:2012 (E)
Contents Page
Foreword .3
2
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SIST EN ISO 9080:2012
EN ISO 9080:2012 (E)
Foreword
This document (EN ISO 9080:2012) has been prepared by Technical Committee ISO/TC 138 "Plastics pipes,
fittings and valves for the transport of fluids" in collaboration 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 April 2013, and conflicting national standards shall be withdrawn at the
latest by April 2013.
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 9080:2003.
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, 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 9080:2012 has been approved by CEN as a EN ISO 9080:2012 without any modification.
3
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SIST EN ISO 9080:2012
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SIST EN ISO 9080:2012
INTERNATIONAL ISO
STANDARD 9080
Second edition
2012-10-15
Plastics piping and ducting systems —
Determination of the long-term
hydrostatic strength of thermoplastics
materials in pipe form by extrapolation
Systèmes de canalisations et de gaines en matières plastiques —
Détermination de la résistance hydrostatique à long terme des matières
thermoplastiques sous forme de tubes par extrapolation
Reference number
ISO 9080:2012(E)
©
ISO 2012
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SIST EN ISO 9080:2012
ISO 9080:2012(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2012
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO’s
member body in the country of the requester.
ISO copyright office
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Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2012 – All rights reserved
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SIST EN ISO 9080:2012
ISO 9080:2012(E)
Contents Page
Foreword .iv
Introduction . v
0.1 General . v
0.2 Principles . v
0.3 Use of the methods . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Acquisition of test data . 3
4.1 Test conditions . 3
4.2 Distribution of internal pressure levels and time ranges . 3
5 Procedure . 3
5.1 Data gathering and analysis . 3
5.2 Extrapolation time factors for polyolefins (semi-crystalline polymers) . 6
5.3 Extrapolation time factors for glassy, amorphous vinyl chloride based polymers . 7
5.4 Extrapolation time factors for polymers other than those covered in 5.2 and 5.3 . 7
6 Example of calculation, software validation . 7
7 Test report . 8
Annex A (normative) Methods of analysis . 9
Annex B (normative) Automatic knee detection .13
Annex C (informative) Application of SEM to stress rupture data of a semi-crystalline polymer .14
Annex D (informative) Application of SEM to stress rupture data of a vinyl chloride based polymer .22
Annex E (informative) Software for calculation of stress-rupture data according to ISO 9080 .28
Bibliography .29
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SIST EN ISO 9080:2012
ISO 9080:2012(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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 9080 was prepared by Technical Committee ISO/TC 138, Plastics pipes, fitings 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 second edition cancels and replaces the first edition (ISO 9080:2003), which has been technically revised.
The following changes have been made:
— all references to lifetime have been removed, as this standard only deals with the mathematics for
extrapolation and the calculation of long-term strength;
— a more accurate description of the number and distribution of the observations and of the use of the
extrapolation has been included;
— the observations in the example of Annex C have been modified in order to comply with the specifications
of this standard and, consequently, the results of the regression calculations have been updated;
— a second set of observations has been added in Annex D in order to provide an evaluation according to
the 3-parameter model (see Annex C), and according to the 4-parameter model (see Annex D);
— a second software package has been evaluated and included in Annex E.
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SIST EN ISO 9080:2012
ISO 9080:2012(E)
Introduction
0.1 General
This Standard Extrapolation Method (SEM) is meant to be used to evaluate the long-term hydrostatic strength
of a material in pipe form. Product standards have specific requirements for the physical and mechanical
properties of the material used for the intended application. It is emphasized that the Standard Extrapolation
Method (SEM) described in this document is not intended to be used to disqualify existing procedures for
arriving at design stresses or allowable pressures for pipelines made of plastics materials, or to disqualify
pipelines made of materials proven by such procedures, for which experience over many years has been
shown to be satisfactory.
Software packages have been developed for the SEM analysis as described in Annex A and Annex B. Windows-
based programmes are commercially available (see Annex E). Use of these software packages is recommended.
0.2 Principles
The suitability of a plastics material for a pressure pipe is determined by its long-term performance under
hydrostatic stress when tested in pipe form, taking into account the envisaged service conditions (e.g.
temperature). For design purposes, it is conventional to express this by means of the hydrostatic (hoop) stress
which a plastics pipe made of the material under consideration is expected to be able to withstand for 50 years
at an ambient temperature of 20 °C using water as the internal test medium. The outside test environment can
be water or air. This method is not intended to imply service life. In certain cases, it is necessary to determine
the value of the hydrostatic strength at either shorter design times or higher temperatures, or on occasion both.
The method given in this International Standard is designed to meet the need for both types of estimate. The
result obtained will indicate the lower prediction limit (LPL), which is the lower confidence limit of the prediction
of the value of the stress that can cause failure in the stated time at a stated temperature.
This International Standard provides a definitive procedure incorporating an extrapolation method using
test data at different temperatures analysed by multiple linear regression analysis. The results permit the
determination of material-specific design values in accordance with the procedures described in the relevant
product standards.
This multiple linear regression analysis is based on the rate processes most accurately described by log (stress)
10
versus log (time) models.
10
In order to assess the predictive value of the model used, it has been considered necessary to make use of
the estimated 97,5 % lower prediction limit (LPL). The 97,5 % lower prediction limit is equivalent to the lower
97,5 % confidence limit for the predicted value. This convention is used in the mathematical calculations to be
consistent with the literature. This aspect necessitates the use of statistical techniques.
The method can provide a systematic basis for the interpolation and extrapolation of stress rupture characteristics
at operating conditions different from the conventional 50 years at 20 °C (see 5.1.5).
Thermoplastic materials in pipe form such as mineral filled thermoplastic polymer, fibre reinforced thermoplastics,
plasticized thermoplastics, blends and alloys may have further considerations with regards to prediction of long
term strength which have to be taken into account in the corresponding product standards.
It is essential that the medium used for pressurizing the pipe does not have an adverse effect on the pipe. In
general, water is considered to be such a medium.
Long consideration was given to deciding which variable should be taken as the independent variable to
calculate the long-term hydrostatic strength. The choice was between time and stress.
The basic question the method has to answer can be formulated in two ways, as indicated below:
a) What is the maximum stress (or pressure) that a given material in pipe form can withstand at a given
temperature for a defined time?
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SIST EN ISO 9080:2012
ISO 9080:2012(E)
b) What is the predicted time to failure for a material in pipe form at a given stress and temperature?
Both questions are relevant.
If the test data for the pipe under study does not show any scatter and if the pipe material can be described
perfectly by the chosen empirical model, the regression with either time independence or stress independence
will be identical. This is never the case because the circumstances of testing are never ideal nor will the
material be 100 % homogeneous. The observations will therefore always show scatter. The regressions
calculated using the two optional independent variables will not be identical and the difference will increase
with increasing scatter.
The variable that is assumed to be most affected by the largest variability (scatter) is the time variable and it
has to be considered as a dependent variable (random variable) in order to allow a correct statistical treatment
of the data set in accordance with this method. However, for practical reasons, the industry prefers to present
stress as a function of time as an independent variable.
0.3 Use of the methods
The purpose of this extrapolation method is to estimate the following:
1)
a) The lower prediction limit (at 97,5 % probability level) of the stress which a pipe made of the material
under consideration is able to withstand for 50 years at an ambient temperature of 20 °C using water or air
as the test environment. In accordance with ISO 12162, the categorised value of this lower prediction limit
is defined as MRS and is used for classification of the material.
b) The value of the lower prediction limit (at 97,5 % probability level) of the stress, either at different design
times or at different temperatures, or on occasion both. In accordance with ISO 12162, the categorised
value of this lower prediction limit is defined as CRSθ and is used for design purposes.
,t
There are several extrapolation models in existence, which have different numbers of terms. This SEM will use
only models with two, three or four parameters.
Adding more terms could improve the fit but would also increase the uncertainty of the predictions.
The SEM describes a procedure for estimating the lower prediction limit (at 97,5 % probability level) whether a
knee (which demonstrates the transition between data type A and type B) is found or not (see Annex B).
The materials are tested in pipe form for the method to be applicable.
The final result of the SEM for a specific material is the lower prediction limit (at 97,5 % probability level) of the
hydrostatic strength, expressed in terms of the hoop stress, at a given time and a given temperature.
For multilayer pipes, the determination of the long-term hydrostatic pressure strength of the products is carried
out in accordance with ISO 17456.
For composite and reinforced thermoplastics pipes, guidance on the use of this method is given in the
product standards.
Guidance for the long-term strength of a specific material with reference lines is given in the appropriate
product standard.
1) In various ISO documents, the lower prediction limit (LPL) is defined incorrectly as the lower confidence limit (LCL),
where LCL is the 97,5 % lower confidence limit for the mean hydrostatic strength.
vi © ISO 2012 – All rights reserved
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SIST EN ISO 9080:2012
INTERNATIONAL STANDARD ISO 9080:2012(E)
Plastics piping and ducting systems — Determination of the
long-term hydrostatic strength of thermoplastics materials in
pipe form by extrapolation
1 Scope
This International Standard specifies a method for predicting the long-term hydrostatic strength of thermoplastics
materials by statistical extrapolation. The method is applicable to all types of thermoplastics pipe at applicable
temperatures. It was developed on the basis of test data from pipe systems.
2 Normative references
The following referenced documents are indispensable for the application 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 1167-1, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of the
resistance to internal pressure — Part 1: General method
ISO 1167-2, Thermoplastics pipes, fittings and assemblies for the conveyance of fluids — Determination of the
resistance to internal pressure — Part 2: Preparation of pipe test pieces
ISO 2507-1:1995, Thermoplastics pipes and fittings — Vicat softening temperature — Part 1: General test method
ISO 3126, Plastics piping systems — Plastics piping components — Measurement and determination of dimensions
ISO 11357-3, Plastics — Differential scanning calorimetry (DSC) — Part 3: Determination of temperature and
enthalpy of melting and crystallization
ISO 12162, Thermoplastics materials for pipes and fittings for pressure applications ― Classification,
designation and design coefficient
ISO 17456, Plastics piping systems — Multilayer pipes — Determination of long-term strength
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
internal pressure
p
force per unit area exerted by the medium in the pipe, in bars
3.2
stress
σ
force per unit area in the wall of the pipe in the hoop (circumferential) direction due to internal pressure, in megapascals
NOTE It is derived from the internal pressure using the following simplified equation:
pd()−e
em y,min
σ =
20e
y,min
where
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SIST EN ISO 9080:2012
ISO 9080:2012(E)
p is the internal pressure, in bars;
d is the mean outside diameter of the pipe, in millimetres;
em
e is the minimum measured wall thickness of the pipe, in millimetres.
y,min
3.3
test temperature
T
t
temperature at which stress rupture data have been determined, in degrees Celsius
3.4
maximum test temperature
T
t,max
maximum temperature at which stress rupture data have been determined, in degrees Celsius
3.5
service temperature
T
s
temperature at which the pipe will be used, in degrees Celsius
3.6
time to failure
t
time to occurrence of a leak in the pipe, in hours
3.7
maximum test time
t
max
time obtained by averaging the logarithms of the five longest times to failure, in hours
3.8
extrapolation time
t
e
time limit for which extrapolation is allowed, in hours
3.9
long-term hydrostatic strength
σ
LTHS
quantity with the dimensions of stress, which represents the predicted mean strength at a temperature T and
time t, in megapascals
3.10
lower confidence limit of the predicted hydrostatic strength
σ
LPL
quantity with the dimensions of stress, which represents the 97,5 % lower confidence limit of the predicted
hydrostatic strength at a temperature T and time t, in megapascals
NOTE It is given by
σ = σ
LPL (T, t, 0,975)
3.11
knee, data type A, data type B
point of intersection of two branches at the same temperature; data points used to calculate the first branch are
designated as type A, data points used to calculate the second branch are designated as type B
3.12
branch
line of constant slope in the log (stress) versus log (time) plot representing the same failure mode
10 10
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SIST EN ISO 9080:2012
ISO 9080:2012(E)
3.13
extrapolation time factor
k
e
factor for calculation of the extrapolation time
4 Acquisition of test data
4.1 Test conditions
The pipe stress rupture data shall be determined in accordance with ISO 1167-1 and ISO 1167-2. The
determination of the resistance to internal pressure shall be carried out using straight pipes.
The mean outside diameter and minimum wall thickness of each pipe test piece shall be determined in
accordance with ISO 3126.
For all calculations, the pipes tested shall be of the same nominal dimension and made from the same batch
of material and come from the same production run.
For existing materials evaluated according to ISO/TR 9080:1992 or ISO 9080:2003, the initial data set may be complemented
by additional data produced from other batches to meet the requirements of 4.2. In such case, the additional data should
be spread regularly at each temperature and documented in the test report.
4.2 Distribution of internal pressure levels and time ranges
4.2.1 For each temperature selected, a minimum of 30 observations shall be obtained, spread over the
testing time. Internal pressure levels shall be selected such that at least four observations will occur above
7 000 h and at least one above 9 000 h (see also 5.1.5). In the event of prediction based on the second branch,
a minimum number of 20 observations is required for the second branches, with a minimum of 5 observations
per temperature.
4.2.2 For all temperatures, times to failure up to 10 h shall be neglected.
4.2.3 At temperatures ≤ 40 °C, times to failure up to 1 000 h may be neglected, provided that the number
of remaining observations conforms to 4.2.1. In that case, at the selected temperature(s), all points below the
selected time shall be discarded.
4.2.4 Test pieces which have not failed above 1 000 h may be used as observations in the multiple linear
regression computations and for the determination of the presence of a knee. Otherwise, they should be
disregarded, provided that the number of remaining observations conforms to 4.2.1.
5 Procedure
5.1 Data gathering and analysis
5.1.1 General
The method is based on multiple linear regression and calculation details given in Annex A. It requires testing
at two or more temperatures and times of 9 000 h or longer and is applicable whether or not indications are
found for the presence of a knee.
5.1.2 Required test data
Obtain test data in accordance with Clause 4 and the following conditions, using two or more
temperatures T , T , …, T :
1 2 n
a) Each pair of adjacent temperatures shall be separated by at least 10 °C and at most 50 °C.
b) One of the test temperatures shall be 20 °C or 23 °C.
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SIST EN ISO 9080:2012
ISO 9080:2012(E)
c) The highest test temperature T shall not exceed the Vicat softening temperature, VST , determined in
t,max B50
accordance with ISO 2507-1:1995 minus 15 °C for glassy amorphous polymers, or the melting temperature
determined in accordance with ISO 11357-3 minus 15 °C for semi-crystalline polymers.
d) The number of observations and the distribution of internal pressure levels at each temperature shall
conform to 4.2.
e) To obtain an optimum estimate of σ , the range of test temperatures shall be selected such that it
LPL
includes the service temperature or range of service temperatures.
Failures resulting from contamination may be disregarded, provided that the number of remaining observations
conforms to 4.2.1.
All valid data points shall be used in the calculations.
For most materials, the test environment and test temperatures are specified in the relevant product standards.
5.1.3 Detection of a knee and validation of data and model
Use the procedure given in Annex B to detect the presence of any knee.
After detecting a knee at any particular temperature, split the data set into two groups, one belonging to the first
branch (data type A), the other belonging to the second branch (data type B).
Fit the multiple linear regression as described in Annex A independently, using all first-branch (type A) data
points for all temperatures and all second-branch (type B) data points for all temperatures.
When studying the data for the occurrence of a knee, attention should be paid to the occurrence of a degradative
failure. Such data (usually characterized by a nearly stress-independent line and visually recognizable) should not
be considered for the calculation, but should only be used for determination of the extrapolation time (see 5.1.5).
If the automatic knee detection does obviously not correspond with the visual examination of the diagram, then
the data points type A and type B in the region of the predicted knee can be manually reclassified to better align
the knee point position with the data. In this case all data points at higher stresses than the stress level of the
reclassified transition from type A to type B data points shall be declared type A and all data points at lower
stresses shall be declared type B. The extrapolation shall be performed again without automatic knee detection.
It is recommended in this case that more data points beyond the time of the predicted knee are obtained.
The reasons for following the manual
...
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