EN IEC 60216-6:2023
(Main)Electrical insulating materials - Thermal endurance properties - Part 6: Determination of thermal endurance indices (TI and RTI) of an insulating material using the fixed time frame method
Electrical insulating materials - Thermal endurance properties - Part 6: Determination of thermal endurance indices (TI and RTI) of an insulating material using the fixed time frame method
This part of IEC 60216 specifies the experimental and calculation procedures for deriving the thermal endurance characteristics, temperature index (TI) and relative temperature index (RTI) of an electrical insulating material (EIM) using the "fixed time frame method (FTFM)". In this protocol, the ageing takes place for a small number of fixed times, using the appropriate number of ageing temperatures throughout each time, the properties of the specimens being measured at the end of the relevant time interval. This differs from the procedure of IEC 60216-1, where ageing is conducted at a small number of fixed temperatures, property measurement taking place after ageing times dependent on the progress of ageing. The diagnostic tests employed in the fixed time frame method are restricted to destructive tests. The method has not yet been applied to non-destructive or proof test procedures. Both the TI and the RTI determined according to the FTFM protocol are derived from experimental data obtained in accordance with the instructions of IEC 60216-1 and IEC 60216-2 as modified in this part of IEC 60216. The calculation procedures and statistical tests are modified from those of IEC 60216-3 and IEC 60216-5.
Elektroisolierstoffe - Eigenschaften hinsichtlich des thermischen Langzeitverhaltens - Teil 6: Bestimmung der thermischen Langzeitkennwerte (TI und RTI) eines Isolierstoffes unter Anwendung des Festzeitrahmenverfahrens
Matériaux isolants électriques - Propriétés d'endurance thermique - Partie 6: Détermination des indices d’endurance thermique (IT et ITR) d’un matériau isolant en utilisant la méthode de trame de durées fixes
IEC 60216-6:2022 est disponible sous forme de IEC 60216-6:2022 RLV qui contient la Norme internationale et sa version Redline, illustrant les modifications du contenu technique depuis l'édition précédente. L’IEC 60216-6:2022 spécifie les procédures expérimentales et de calcul à utiliser pour déduire les caractéristiques d’endurance thermique, l’indice de température (IT) et l’indice de température relatif (ITR) d’un matériau isolant électrique (MIE) à l’aide de la "méthode de trame de durées fixes" (FTFM - fixed time frame method). Avec ce protocole, le vieillissement se produit après un petit nombre de durées déterminées, en utilisant le nombre approprié de températures de vieillissement tout au long de chaque durée pertinente, et les propriétés des éprouvettes sont mesurées à la fin de chaque intervalle de temps. Ce protocole diffère de la procédure de l’IEC 60216-1, dans laquelle le vieillissement est effectué à un petit nombre de températures déterminées, et le mesurage des propriétés des éprouvettes est effectué après des temps de vieillissement variables en fonction de la progression du vieillissement. Les essais de diagnostic utilisés dans la méthode de trame de durées fixes sont limités aux essais destructifs. La méthode n’a pas encore été appliquée aux essais non destructifs ni aux procédures d’essais d’épreuve. Cette édition inclut les modifications techniques majeures suivantes par rapport à l'édition précédente: - clarification de la définition des propriétés d’indice par rapport aux propriétés d’endurance; - remaniement complet de l’Annexe G et du programme correspondant.
Elektroizolacijski materiali - Lastnosti v zvezi s toplotno vzdržljivostjo - 6. del: Ugotavljanje indeksov toplotne vzdržljivosti (TI in RTI) izolacijskega materiala z uporabo metode fiksnih časovnih okvirov (IEC 60216-6:2022)
Ta del standarda IEC 60216 določa eksperimentalne in računske postopke za izpeljavo lastnosti toplotne vzdržljivosti, toplotnega indeksa (TI) in relativnega toplotnega indeksa (RTI) elektroizolacijskega materiala (EIM) z uporabo metode »fiksnih časovnih okvirov (FTFM)«.
Po tem protokolu staranje poteka v fiksnih časovnih okvirih ob različnih temperaturah staranja skozi vsak interval, lastnosti vzorcev pa se merijo na koncu ustreznega časovnega intervala. Postopek je drugačen od tistega v standardu IEC 60216-1, kjer se staranje izvaja pri majhnem številu fiksnih temperatur, meritve lastnosti pa se izvajajo po časih staranja, ki so odvisni od napredka staranja.
Diagnostični preskusi, uporabljeni pri metodi fiksnih časovnih okvirov, so omejeni na porušitvene preskuse. Metoda še ni bila uporabljena za neporušitvene ali dokazne postopke preskušanja.
Tako toplotni indeks kot relativni toplotni indeks, določena v skladu s protokolom fiksnih časovnih okvirov, izhajata iz eksperimentalnih podatkov, dobljenih v skladu z navodili iz standardov IEC 60216-1 in IEC 60216-2, kot sta spremenjena v tem delu IEC 60216. Računski postopki in statistični preskusi dopolnjujejo postopke iz standardov IEC 60216-3 in IEC 60216-5.
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
01-marec-2023
Elektroizolacijski materiali - Lastnosti v zvezi s toplotno vzdržljivostjo - 6. del:
Ugotavljanje indeksov toplotne vzdržljivosti (TI in RTI) izolacijskega materiala z
uporabo metode fiksnih časovnih okvirov (IEC 60216-6:2022)
Electrical insulating materials - Thermal endurance properties - Part 6: Determination of
thermal endurance indices (TI and RTI) of an insulating material using the fixed time
frame method (IEC 60216-6:2022)
Elektroisolierstoffe - Eigenschaften hinsichtlich des thermischen Langzeitverhaltens - Teil
6: Bestimmung der thermischen Langzeitkennwerte (TI und RTI) eines Isolierstoffes
unter Anwendung des Festzeitrahmenverfahrens (IEC 60216-6:2022)
Matériaux isolants électriques - Propriétés d'endurance thermique - Partie 6:
Détermination des indices d’endurance thermique (IT et ITR) d’un matériau isolant en
utilisant la méthode de trame de durées fixes (IEC 60216-6:2022)
Ta slovenski standard je istoveten z: EN IEC 60216-6:2023
ICS:
29.035.01 Izolacijski materiali na Insulating materials in
splošno general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
EUROPEAN STANDARD EN IEC 60216-6
NORME EUROPÉENNE
EUROPÄISCHE NORM January 2023
ICS 17.220.99; 29.035.01 Supersedes EN 60216-6:2006
English Version
Electrical insulating materials - Thermal endurance properties -
Part 6: Determination of thermal endurance indices (TI and RTI)
of an insulating material using the fixed time frame method
(IEC 60216-6:2022)
Matériaux isolants électriques - Propriétés d'endurance Elektroisolierstoffe - Eigenschaften hinsichtlich des
thermique - Partie 6: Détermination des indices thermischen Langzeitverhaltens - Teil 6: Bestimmung der
d'endurance thermique (IT et ITR) d'un matériau isolant en thermischen Langzeitkennwerte (TI und RTI) eines
utilisant la méthode de trame de durées fixes Isolierstoffes unter Anwendung des
(IEC 60216-6:2022) Festzeitrahmenverfahrens
(IEC 60216-6:2022)
This European Standard was approved by CENELEC on 2023-01-02. CENELEC 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 CENELEC 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 CENELEC member into its own language and notified to the CEN-CENELEC Management Centre has the
same status as the official versions.
CENELEC members are the national electrotechnical committees of Austria, Belgium, Bulgaria, Croatia, Cyprus, the Czech Republic,
Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, the
Netherlands, Norway, Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Türkiye and the United Kingdom.
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2023 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC Members.
Ref. No. EN IEC 60216-6:2023 E
European foreword
The text of document 112/583/FDIS, future edition 3 of IEC 60216-6, prepared by IEC/TC 112
"Evaluation and qualification of electrical insulating materials and systems" was submitted to the IEC-
CENELEC parallel vote and approved by CENELEC as EN IEC 60216-6:2023.
The following dates are fixed:
• latest date by which the document has to be implemented at national (dop) 2023-10-02
level by publication of an identical national standard or by endorsement
• latest date by which the national standards conflicting with the (dow) 2026-01-02
document have to be withdrawn
This document supersedes EN 60216-6:2006 and all of its amendments and corrigenda (if any).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CENELEC shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national committee. A
complete listing of these bodies can be found on the CENELEC website.
Endorsement notice
The text of the International Standard IEC 60216-6:2022 was approved by CENELEC as a European
Standard without any modification.
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications
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.
NOTE 1 Where an International Publication has been modified by common modifications, indicated by (mod), the
relevant EN/HD applies.
NOTE 2 Up-to-date information on the latest versions of the European Standards listed in this annex is available
here: www.cenelec.eu.
Publication Year Title EN/HD Year
IEC 60212 - Standard conditions for use prior to and EN 60212 -
during the testing of solid electrical
insulating materials
IEC 60216-1 2013 Electrical insulating materials - Thermal EN 60216-1 2013
endurance properties - Part 1: Ageing
procedures and evaluation of test results
IEC 60216-2 - Electrical insulating materials - Thermal EN 60216-2 -
endurance properties - Part 2:
Determination of thermal endurance
properties of electrical insulating materials
- Choice of test criteria
IEC 60216-3 2021 Electrical insulating materials - Thermal EN IEC 60216-3 2021
endurance properties - Part 3: Instructions
for calculating thermal endurance
characteristics
IEC 60216-4-1 - Electrical insulating materials - Thermal EN 60216-4-1 -
endurance properties - Part 4-1: Ageing
ovens - Single-chamber ovens
IEC 60216-4-2 - Electrical insulating materials - Thermal EN 60216-4-2 -
endurance properties - Part 4-2: Ageing
ovens - Precision ovens for use up to 300
°C
IEC 60216-4-3 - Electrical insulating materials - Thermal EN 60216-4-3 -
endurance properties - Part 4-3: Ageing
ovens - Multi-chamber ovens
IEC 60216-5 2022 Electrical insulating materials - Thermal EN 60216-5 2022
endurance properties - Part 5:
Determination of relative temperature index
(RTI) of an insulating material
IEC 60493-1 - Guide for the statistical analysis of ageing - -
test data - Part 1: Methods based on mean
values of normally distributed test results
IEC 60216-6 ®
Edition 3.0 2022-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Electrical insulating materials – Thermal endurance properties –
Part 6: Determination of thermal endurance indices (TI and RTI) of an insulating
material using the fixed time frame method
Matériaux isolants électriques – Propriétés d'endurance thermique –
Partie 6: Détermination des indices d’endurance thermique (IT et ITR) d’un
matériau isolant en utilisant la méthode de trame de durées fixes
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 17.220.99; 29.035.01 ISBN 978-2-8322-6022-7
– 2 – IEC 60216-6:2022 © IEC 2022
CONTENTS
FOREWORD . 5
1 Scope . 7
2 Normative references . 7
3 Terms, definitions, symbols and abbreviated terms . 8
3.1 Terms and definitions . 8
3.2 Symbols and abbreviated terms . 11
4 FTFM protocol . 12
4.1 Principles of FTFM protocol . 12
4.2 Objective of FTFM protocol . 12
5 TI determination . 13
5.1 Ageing procedures . 13
5.2 Ageing times and temperatures . 13
5.3 Test specimens . 13
5.3.1 Preparation . 13
5.3.2 Number of specimens . 14
5.4 Diagnostic tests . 14
5.5 Selection of end-points . 15
5.6 Establishment of initial property value . 15
5.7 Ageing conditions . 15
5.7.1 Ageing ovens . 15
5.7.2 Environmental conditions . 15
5.7.3 Conditions for property measurement . 16
5.8 Procedure for ageing . 16
6 Calculation procedures . 16
6.1 General principles . 16
6.1.1 Thermal endurance calculation . 16
6.1.2 Property value – equivalent temperature transform (Calculation of
hypothetical ageing temperature derived from the value of a property) . 17
6.2 Precision of calculations . 17
6.3 Derivation of temperatures equivalent to property values . 17
6.3.1 General . 17
6.3.2 Preliminary calculations . 17
6.3.3 Regression calculations (property on temperature) . 18
6.3.4 Linearity test . 20
6.3.5 Estimation of end-point temperatures equivalent to property values . 21
6.4 Regression analysis (temperature on time) . 21
6.4.1 General . 21
6.4.2 Group means and variances . 21
6.4.3 General means and variances . 21
6.4.4 Regression . 22
6.5 Statistical tests . 23
6.5.1 Variance equality test . 23
6.5.2 Linearity test (F-test) . 24
6.5.3 Estimates of x and y and their confidence limits . 24
6.6 Thermal endurance graph . 26
7 Calculation and requirements for results . 26
IEC 60216-6:2022 © IEC 2022 – 3 –
7.1 Calculation of thermal endurance characteristics . 26
7.2 Reporting of results . 27
7.2.1 Summary of statistical tests and reporting . 27
7.2.2 Report format . 27
8 Report . 27
9 RTI determination . 28
10 Additional symbols. 28
11 Experimental procedures . 29
11.1 Selection of reference EIM . 29
11.2 Selection of diagnostic test for extent of ageing . 29
11.3 Ageing procedures . 29
12 Calculation procedures . 29
12.1 General principles . 29
12.2 Input data . 29
12.3 RTI . 30
12.4 Confidence limits . 31
12.5 Extrapolation. 32
13 Results and report . 33
13.1 Results of statistical and numerical tests. 33
13.2 Result . 33
13.3 Report. 33
Annex A (normative) Decision flow chart . 34
Annex B (normative) Decision table . 36
Annex C (informative) Statistical tables . 37
Annex D (informative) Suggested ageing times and temperatures . 41
D.1 TI determination . 41
D.1.1 Correlation time (TI) = 20 000 h . 41
D.1.2 Other correlation times for TI calculation (see 12.3) . 41
D.2 RTI determination . 42
Annex E (informative) Figures . 43
Annex F (normative) Statistical significance of the difference between two regression
estimates . 46
Annex G (informative) Computer program . 47
G.1 General . 47
G.1.1 Overview . 47
G.1.2 Convenience program execution . 48
G.2.1 Content of file Control6.ftd . 50
G.2.2 Report . 52
G.2.3 Thermal endurance graph . 54
Figure A.1 – Decision flow chart . 35
Figure E.1 – Property-temperature graph with regression line . 43
Figure E.2 – Thermal endurance graph . 43
Figure E.3 – Ageing times and temperatures in relation to thermal endurance graph. 44
Figure E.4 – Ageing times and temperatures in relation to thermal endurance graph. 44
Figure E.5 – Ageing times and temperatures in relation to thermal endurance graph. 45
– 4 – IEC 60216-6:2022 © IEC 2022
Figure G.1 – Shortcut property dialog for program launch . 49
Figure G.2 – Thermal endurance graph . 54
Table 1 – Intermediate data values . 30
Table B.1 – Decision table . 36
Table C.1 – χ -function . 37
Table C.2 – t-function . 37
Table C.3 – F-function, P = 0,05 . 38
Table C.4 – F-function, P = 0,005 . 39
Table D.1 – Ageing temperatures and times . 41
IEC 60216-6:2022 © IEC 2022 – 5 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ELECTRICAL INSULATING MATERIALS –
THERMAL ENDURANCE PROPERTIES –
Part 6: Determination of thermal endurance indices (TI and RTI)
of an insulating material using the fixed time frame method
FOREWORD
1) The International Electrotechnical Commission (IEC) is a worldwide organization for standardization comprising
all national electrotechnical committees (IEC National Committees). The object of IEC is to promote international
co-operation on all questions concerning standardization in the electrical and electronic fields. To this end and
in addition to other activities, IEC publishes International Standards, Technical Specifications, Technical Reports,
Publicly Available Specifications (PAS) and Guides (hereafter referred to as “IEC Publication(s)”). Their
preparation is entrusted to technical committees; any IEC National Committee interested in the subject dealt with
may participate in this preparatory work. International, governmental and non-governmental organizations liaising
with the IEC also participate in this preparation. IEC collaborates closely with the International Organization for
Standardization (ISO) in accordance with conditions determined by agreement between the two organizations.
2) The formal decisions or agreements of IEC on technical matters express, as nearly as possible, an international
consensus of opinion on the relevant subjects since each technical committee has representation from all
interested IEC National Committees.
3) IEC Publications have the form of recommendations for international use and are accepted by IEC National
Committees in that sense. While all reasonable efforts are made to ensure that the technical content of IEC
Publications is accurate, IEC cannot be held responsible for the way in which they are used or for any
misinterpretation by any end user.
4) In order to promote international uniformity, IEC National Committees undertake to apply IEC Publications
transparently to the maximum extent possible in their national and regional publications. Any divergence between
any IEC Publication and the corresponding national or regional publication shall be clearly indicated in the latter.
5) IEC itself does not provide any attestation of conformity. Independent certification bodies provide conformity
assessment services and, in some areas, access to IEC marks of conformity. IEC is not responsible for any
services carried out by independent certification bodies.
6) All users should ensure that they have the latest edition of this publication.
7) No liability shall attach to IEC or its directors, employees, servants or agents including individual experts and
members of its technical committees and IEC National Committees for any personal injury, property damage or
other damage of any nature whatsoever, whether direct or indirect, or for costs (including legal fees) and
expenses arising out of the publication, use of, or reliance upon, this IEC Publication or any other IEC
Publications.
8) Attention is drawn to the Normative references cited in this publication. Use of the referenced publications is
indispensable for the correct application of this publication.
9) Attention is drawn to the possibility that some of the elements of this IEC Publication may be the subject of patent
rights. IEC shall not be held responsible for identifying any or all such patent rights.
IEC 60216-6 has been prepared by IEC technical committee 112: Evaluation and qualification
of electrical insulating materials and systems. It is an International Standard.
This third edition cancels and replaces the second edition published in 2006. This
edition constitutes a technical revision.
This edition includes the following significant technical changes with respect to the previous
edition:
a) clarification of definition of index properties vs. endurance properties;
b) complete rework of Annex G and the corresponding program.
– 6 – IEC 60216-6:2022 © IEC 2022
The text of this International Standard is based on the following documents:
Draft Report on voting
112/583/FDIS 112/589/RVD
Full information on the voting for its approval can be found in the report on voting indicated in
the above table.
The language used for the development of this International Standard is English.
This document was drafted in accordance with ISO/IEC Directives, Part 2, and developed in
accordance with ISO/IEC Directives, Part 1 and ISO/IEC Directives, IEC Supplement, available
at www.iec.ch/members_experts/refdocs. The main document types developed by IEC are
described in greater detail at www.iec.ch/standardsdev/publications.
A list of all parts in the IEC 60216 series, published under the general title Electrical insulating
materials – Thermal endurance properties, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under webstore.iec.ch in the data related to the
specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The "colour inside" logo on the cover page of this document indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.
IEC 60216-6:2022 © IEC 2022 – 7 –
ELECTRICAL INSULATING MATERIALS –
THERMAL ENDURANCE PROPERTIES –
Part 6: Determination of thermal endurance indices (TI and RTI)
of an insulating material using the fixed time frame method
1 Scope
This part of IEC 60216 specifies the experimental and calculation procedures for deriving the
thermal endurance characteristics, temperature index (TI) and relative temperature index (RTI)
of an electrical insulating material (EIM) using the “fixed time frame method (FTFM)”.
In this protocol, the ageing takes place for a small number of fixed times, using the appropriate
number of ageing temperatures throughout each time, the properties of the specimens being
measured at the end of the relevant time interval. This differs from the procedure of IEC 60216-
1, where ageing is conducted at a small number of fixed temperatures, property measurement
taking place after ageing times dependent on the progress of ageing.
The diagnostic tests employed in the fixed time frame method are restricted to destructive tests.
The method has not yet been applied to non-destructive or proof test procedures.
Both the TI and the RTI determined according to the FTFM protocol are derived from
experimental data obtained in accordance with the instructions of IEC 60216-1 and IEC 60216-2
as modified in this part of IEC 60216. The calculation procedures and statistical tests are
modified from those of IEC 60216-3 and IEC 60216-5.
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.
IEC 60212, Standard conditions for use prior to and during the testing of solid electrical
insulating materials
IEC 60216-1:2013, Electrical insulating materials –Thermal endurance properties – Part 1:
Ageing procedures and evaluation of test results
IEC 60216-2, Electrical insulating materials – Thermal endurance properties – Part 2:
Determination of thermal endurance properties of electrical insulating materials – Choice of test
criteria
IEC 60216-3:2021, Electrical insulating materials – Thermal endurance properties – Part 3:
Instructions for calculating thermal endurance characteristics
IEC 60216-4-1, Electrical insulating materials – Thermal endurance properties – Part 4-1:
Ageing ovens – Single-chamber ovens
IEC 60216-4-2, Electrical insulating materials – Thermal endurance properties – Part 4-2:
Ageing ovens – Precision ovens for use up to 300 °C
– 8 – IEC 60216-6:2022 © IEC 2022
IEC 60216-4-3, Electrical insulating materials – Thermal endurance properties – Part 4-3:
Ageing ovens – Multi-chamber ovens
IEC 60216-5:2022, Electrical insulating materials – Thermal endurance properties – Part 5:
Determination of relative temperature index (RTI) of an insulating material
IEC 60493-1, Guide for the statistical analysis of ageing test data – Part 1: Methods based on
mean values of normally distributed test results
3 Terms, definitions, symbols and abbreviated terms
3.1 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at https://www.electropedia.org/
• ISO Online browsing platform: available at https://www.iso.org/obp
3.1.1
electrical insulating material
EIM
material of low electric conductivity, used to separate conducting parts at different electric
potentials or to isolate such parts from the surroundings
3.1.2
assessed temperature index
ATI
numerical value of the temperature index in degrees Celsius of the reference EIM
Note 1 to entry: The ATI of a specific material may vary between different applications of the material.
3.1.3
ageing temperature
temperature in degrees Celsius at which a group of specimens is thermally aged
3.1.4
end-point temperature
temperature in degrees Celsius at which a specimen is considered to have reached end-point
after ageing for a specified time
3.1.5
candidate EIM
material for which an estimate of the thermal endurance is required to be determined
Note 1 to entry: The determination is made by simultaneous thermal ageing of the material and a reference EIM.
3.1.6
central second moment of a data group
sum of the squares of the differences between the data values and the value of the group mean
divided by the number of data items in the group
3.1.7
95 % confidence limit
statistical parameter, calculated from test data, which with 95 % confidence constitutes an
upper or lower limit for the true value of a quantity estimated by statistical analysis
IEC 60216-6:2022 © IEC 2022 – 9 –
Note 1 to entry: This implies that there is only 5 % probability that the true value of the quantity estimated is actually
larger (or smaller) than the upper (or lower) confidence limit.
Note 2 to entry: In other connections, confidence values other than 95 % may sometimes be used, e.g. in the
linearity test for destructive test data.
3.1.8
reference EIM
material with known thermal endurance, preferably derived from service experience, used as a
reference for comparative tests with the candidate EIM
3.1.9
correlation coefficient
number expressing the completeness of the relation between members of two data sets, equal
to the covariance divided by the square root of the product of the variances of the sets
Note 1 to entry: The value of its square is between 0 (no correlation) and 1 (complete correlation).
Note 2 to entry: In this standard, the two data sets are the values of the independent variable and the means of the
corresponding dependent variable groups.
3.1.10
correlation time for RTI
estimated time to end-point of the reference EIM at a temperature equal to its ATI in degrees
Celsius
Note 1 to entry: In this document, it is expressed by symbol τ , see Clause 10.
c
3.1.11
correlation time for TI
hypothetical time to end-point used to calculate TI
Note 1 to entry: Its usual value is 20 000 h, see Clause D.1.
3.1.12
covariance,
for two sets of data with equal numbers of elements where each element in one set corresponds
to one in the other, sum of the products of the deviations of the corresponding members from
their set means, divided by the number of degrees of freedom
3.1.13
degrees of freedom
number of data values minus the number of parameter values
3.1.14
destructive test
diagnostic property test, where the test specimen is irreversibly changed by the property
measurement, in a way which precludes a repeated measurement on the same specimen
Note 1 to entry: An example of a destructive test is the measurement of electric strength. An example of a non-
destructive test is the measurement of dissipation factor tan δ.
3.1.15
end-point line
line parallel to the temperature axis intercepting the property axis at the end-point value
3.1.16
halving interval
HIC
numerical value of the temperature interval in Kelvin which expresses the halving of the time to
end-point taken at a time equal to TI
– 10 – IEC 60216-6:2022 © IEC 2022
3.1.17
regression analysis
process of deducing the best fit line expressing the relation of corresponding members of two
data groups by minimizing the sum of squares of deviations of members of one of the groups
from the line
3.1.18
regression coefficients
coefficients of the equation of the best fit line derived by regression analysis
3.1.19
relative temperature index
RTI
determined by test in relation to the thermal performance of a known reference EIM
3.1.20
significance
probability of a value of a statistical function greater than a specified value
Note 1 to entry: The value is equal to (1–p) where p is the cumulative distribution function value. Significance is
conventionally printed in upper case (P).
3.1.21
standard deviation
square root of the variance of a data group or sub-group
3.1.22
standard error of an estimate of the true value of a data group property
value of the standard deviation of the hypothetical sampling population of which the group
property may be a member
Note 1 to entry: For an estimate of the group mean, the standard error is equal to the group standard deviation
divided by the square root of the number of data items in the group, and indicates the uncertainty in the estimate of
the true value of the mean. This standard is concerned only with means and the difference between two means.
3.1.23
temperature index
TI
numerical value of the temperature in degrees Celsius determined by test by itself
Note 1 to entry: This rating is based on 20 000 h life, unless otherwise specified, based on one of the end-of-life
criteria listed in IEC 60216-2.
3.1.24
temperature group,
number of specimens being exposed together to thermal ageing at the same temperature in the
same oven
Note 1 to entry: Where there is no risk of ambiguity, either temperature groups or test groups may be referred to
simply as “groups”.
3.1.25
test group,
number of specimens removed together from a temperature group for destructive testing
Note 1 to entry: Where there is no risk of ambiguity, either temperature groups or test groups may be referred to
simply as “groups”.
3.1.26
thermal endurance graph
graph in which the logarithm of the time to reach a specified end-point in a thermal endurance
test is plotted against the reciprocal thermodynamic (absolute) test temperature
IEC 60216-6:2022 © IEC 2022 – 11 –
3.1.27
thermal endurance graph paper
graph paper having a logarithmic time scale as the ordinate and values proportional to the
reciprocal of the thermodynamic (absolute) temperature as the abscissa
Note 1 to entry: The ordinate is usually graduated in powers of ten (from 10 h to 100 000 h is often a convenient
range). The abscissa is usually graduated in a non-linear (Celsius) temperature scale oriented with temperature
increasing from left to right.
3.1.28
time group,
all test groups removed for testing at the same time
3.1.29
variance of a data group
sum of the squares of the deviations of the data from a reference level defined by one or more
parameters divided by the number of degrees of freedom
Note 1 to entry: The reference level can, for example be a mean value (1 parameter) or a line (2 parameters, here
intercept on the axis of the independent variable and slope).
3.2 Symbols and abbreviated terms
The following symbols are used in the calculations of Clauses 6, 7, 12 and Annex A, Annex B
and Annex C.
Symbol Description Clause
a Regression coefficient: intercept of regression line with x-axis 6.4.4
b Regression coefficient: slope of regression line relative to y-axis 6.4.4
6.5.3
ˆ
b
r
Y
Parameter derived from b for calculation of
c
b
p Regression coefficient for destructive test calculations 6.3.5
c 6.5.1
Parameter in calculation of χ
6.3.4,
F F-distributed variance ratio for linearity test
6.5.2
g, h, i, j Indexing parameters for regression calculations 6.3, 6.4
HIC Halving interval 7.1
k Number of ageing times 6.1.1
Total number of x values 6.4.3
N
ij
n Number of x values in time group i 6.1.1
i ij
Annex A,
Annex B
P Significance of the value of a statistical test function
and
Annex C
p 6.3
End-point property value
e
p 6.3
Property value h in temperature group g (time group i implied)
gh
6.3
p
Mean property value in temperature group g (time group i implied)
g
q 6.5.1
Base of logarithms in calculation of χ
r Number of temperature groups selected in time group i 6.3.3
Square of correlation coefficient 6.4.4
r
– 12 – IEC 60216-6:2022 © IEC 2022
Symbol Description Clause
6.5.2
Total (non-regression) variance of x-values
s
Variance of property values in temperature group g (time group i 6.3.3
s
1g
implied)
6.5.2
Value of s adjusted to allow for acceptable non-linearity
s
a
6.5.3
ˆ
Y
Parameter derived from s for calculation of
s
c
r
t Student's t-distributed stochastic variable 6.5.3
7.1
TC, TC
a s
Lower confidence limit of TI or TI (see above)
a
a
t 6.5.3
Value of t with probability p and N degrees of freedom
p,N
x 6.3.5
Value of x, index number j, in time group i
ij
x
General mean of x-values 6.4.3
6.5.3
ˆˆ
XX, Estimate of x, and its confidence limit
c
y 6.1.1
Value of y for time group i
i
y
General mean of y-values 6.4.3
6.5.3
ˆˆ
YY,
Estimate of y, and its confidence limit
c
Reciprocal kelvin temperature for 6.1.1
z ϑ
ij
ij
nd
µ (y)
6.4.3
2 Central 2 moment of y values
Total number of property values in time group (i implied) 6.3.3
ν
2 2
6.5.1
χ χ distributed variable for variance equality (Bartlett's) test
ϑ
ij
Ageing temperature for specimen group j in time group i 6.1.1
Θ
273,15 K (corresponding to 0 °C) 6.1.1
τ
i Ageing time for time group i 6.1.1
4 FTFM protocol
4.1 Principles of FTFM protocol
The FTFM (fixed time frame method) protocol is based upon the principle that thermal ageing
for determination of thermal endurance characteristics is carried out over a small number of
fixed times, with a sufficient range of ageing temperatures at each time to ensure that the
property values determined reach the end-point in a satisfactory manner.
In this it differs from the fixed temperature frame procedure of IEC 60216-1, where a small
number of ageing temperatures is employed, with ageing being carried out with testing at
intervals, until the end-point has been reached.
4.2 Objective of FTFM protocol
The protocol shall achieve the following advantages:
The determination of thermal endurance characteristics is completed in a fixed, predetermined
time.
IEC 60216-6:2022 © IEC 2022 – 13 –
This enables much more efficient planning of the determination and will often have substantial
commercial advantage. A simple TI determination can be completed in 5 kh, whereas by the
fixed temperature frame procedure, it can be necessary for ageing to be considerably prolonged
past this time to achieve the end-point at the lowest chosen ageing temperature.
Each temperature to end-point (i.e. time-group mean) in the thermal endurance regression is
based on the temperatures selected in a time group. The number of temperatures selected may
be any number between three and the number of temperature groups in a time group.
Since the largest source of systematic error in the fixed temperature frame procedure is
temperature error (actual indication error or temperature distribution error), systematic errors
can be considerably reduced. Errors from this source can lead to results which are either
inaccurate or invalid through incorrect assessment of linearity.
5 TI determination
5.1 Ageing procedures
Each test procedure shall specify the shape, dimensions and number of the test specimens, the
times of exposure, the property to which TI is related, the methods of its determination, the end-
point, and the derivation of the thermal endurance characteristics from the experimental data.
The chosen property should, if possible, reflect in a significant fashion a function of the EIM in
practical use. A choice of properties is given in IEC 60216-2.
To provide uniform conditions, the conditioning of specimens after removal from the oven and
before measurement should be specified.
5.2 Ageing times and temperatures
In the majority of cases, the required thermal endurance characteristics are for a projected
duration of 20 000 h. However, there is often a need for such information related to other, longer
or shorter times. In cases of longer times, the times given as requirements or recommendations
in the text of this standard (e.g. 5 kh for the minimum value of the longest ageing time) shall be
increased in the ratio of the actual specification time to 20 kh.
In cases of shorter specification times, the related times may be decreased in the same ratio if
necessary.
Particular care will be needed for very short specification times, since the higher ageing
temperatures can lead into temperature regions which include transition points, e.g. glass
transition temperature or partial melting, with consequent non-linearity. Very long specification
times can also lead to non-linearity.
Recommendations for ageing times and temperatures are given in Annex D and illustrated in
Figure E.3 to Figure E.5.
5.3 Test specimens
5.3.1 Preparation
The specimens used for the ageing test shall constitute a random sample from the population
investigated and shall be treated uniformly.
Since processing conditions may significantly affect the ageing characteristics of some EIMs, it
shall be ensured that, for example, sampling, cutting sheet from the supply roll, cutting of
anisotropic material in a given direction, moulding, curing, preconditioning, are performed in the
same manner for all specimens.
– 14 – IEC 60216-6:2022 © IEC 2022
The material specifications or the standards for the diagnostic test methods will contain all
necessary instructions for the preparation of specimens.
The thickness of specimens is in some cases specified in the list of property measurements for
the determination of thermal endurance. See IEC 60216-2. If not, the thickness shall be
reported. Some physical prop
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.
Loading comments...