IEC 62506:2023

Methods for product accelerated testing

IEC 62506:2023 provides guidance on the application of various accelerated test techniques for measurement or improvement of item reliability. Identification of potential failure modes that can be experienced in the use of an item and their mitigation is instrumental to ensure dependability of an item. The object of the methods is to either identify potential design weakness or provide information on item reliability, or to achieve necessary reliability and availability improvement, all within a compressed or accelerated period of time. This document addresses accelerated testing of non-repairable and repairable systems. It can be used for probability ratio sequential tests, fixed duration tests and reliability improvement/growth tests, where the measure of reliability can differ from the standard probability of failure occurrence. This document also extends to present accelerated testing or production screening methods that would identify weakness introduced into the item by manufacturing error, which can compromise item reliability. Services and people are however not covered by this document.

Méthodes d'essais accélérés de produits

L'IEC 62506:2023 fournit des recommandations pour l’application de diverses techniques d’essais accélérés permettant de mesurer ou d’améliorer la fiabilité de l’entité. L’identification des modes de défaillance potentiels qui peuvent être rencontrés lors de l’utilisation d’une entité donnée et la manière d’y remédier contribuent à assurer la sûreté de fonctionnement d’une entité. L’objectif de ces méthodes est soit d’identifier les faiblesses potentielles de la conception et fournir des informations sur la fiabilité de l’entité, soit d’atteindre l’amélioration nécessaire de la fiabilité et de la disponibilité, dans les deux cas en comprimant ou en accélérant la durée. Le présent document couvre les essais accélérés de systèmes non réparables et de systèmes réparables. Elle peut être utilisée pour des essais de rapport de probabilité progressifs, des essais à durée fixe et des essais d’amélioration/croissance de la fiabilité, lorsque la mesure de la fiabilité peut être différente de la probabilité normale d’occurrence de défaillance. Le présent document décrit également des méthodes d’essais accélérés ou de déverminage de la production qui permettraient d’identifier les faiblesses induites par une éventuelle erreur de fabrication de l’entité et qui peuvent de ce fait d’en compromettre la fiabilité. Les services et les personnes ne sont cependant pas couverts par le présent document.

General Information

• Status: Published
• Publication Date: 06-Nov-2023
• ICS: 03.120.01 - Quality in general
• ICS: 21.020 - Characteristics and design of machines, apparatus, equipment
• Technical Committee: TC 56 - Dependability
• Drafting Committee: MT 32 - TC 56/MT 32
• Current Stage: PPUB - Publication issued
• Start Date: 24-Nov-2023
• Completion Date: 07-Nov-2023

Relations

• Revises: IEC 62506:2013 - Methods for product accelerated testing
• Effective Date: 05-Sep-2023

Standards Content (Sample)

IEC 62506 ®
Edition 2.0 2023-11
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Methods for product accelerated testing
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
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copyright or have an enquiry about obtaining additional rights to this publication, please contact the address below or
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About the IEC
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International Standards for all electrical, electronic and related technologies.

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IEC 62506 ®
Edition 2.0 2023-11
COMMENTED VERSION
INTERNATIONAL
STANDARD
colour
inside
Methods for product accelerated testing
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 03.120.01, 21.020 ISBN 978-2-8322-7828-4

– 2 – IEC 62506:2023 CMV © IEC 2023
CONTENTS
FOREWORD .5
INTRODUCTION .7
1 Scope .8
2 Normative references .8
3 Terms, definitions, symbols and abbreviated terms .9
3.1 Terms and definitions .9
3.2 Symbols and abbreviated terms . 11
4 General description of the accelerated test methods . 12
4.1 Cumulative damage model . 12
4.2 Classification, methods and types of test acceleration . 15
4.2.1 General . 15
4.2.2 Type A: qualitative accelerated tests . 16
4.2.3 Type B: quantitative accelerated tests . 16
4.2.4 Type C: quantitative time and event compressed tests . 17
5 Accelerated test models . 18
5.1 Type A, qualitative accelerated tests . 18
5.1.1 Highly accelerated limit tests (HALT) . 18
5.1.2 Highly accelerated stress test (HAST) . 23
5.1.3 Highly accelerated stress screening/ or audit (HASS/ or HASA) . 23
5.1.4 Engineering aspects of HALT and HASS . 24
5.2 Types B and C – Quantitative accelerated test methods . 25
5.2.1 Purpose of quantitative accelerated testing . 25
5.2.2 Physical basis for the quantitative accelerated Type B test methods . 25
5.2.3 Type C tests, time (C ) and event (C ) compression . 27
1 2
5.3 Failure mechanisms and test design . 28
5.4 Determination of stress levels, profiles and combinations in use and test –
Stress modelling . 29
5.4.1 General . 29
5.4.2 Step-by-step procedure . 29
5.5 Multiple stress acceleration methodology – Type B tests . 30
5.6 Single and multiple stress acceleration for Type B tests . 33
5.6.1 Single stress acceleration methodology . 33
5.6.2 Stress models with stress varying as a function of time – Type B tests . 41
5.6.3 Stress models that depend on repetition of stress applications – Fatigue
models . 43
5.6.4 Other acceleration models – Time and event compression . 45
5.7 Acceleration of quantitative reliability tests . 46
5.7.1 Reliability requirements, goals, and use profile . 46
5.7.2 Accelerated testing for reliability demonstration or life tests . 48
5.7.3 Testing of components for a reliability measure . 61
5.7.4 Reliability measures for components and systems/items . 62
5.8 Accelerated reliability compliance or evaluation tests . 63
5.9 Accelerated reliability growth testing . 65
5.10 Guidelines for accelerated testing . 65
5.10.1 Accelerated testing for multiple stresses and the known use profile . 65
5.10.2 Level of accelerated stresses . 65
5.10.3 Accelerated reliability and verification tests . 66

6 Accelerated testing strategy in product development . 66
6.1 Accelerated testing sampling plan . 66
6.2 General discussion about test stresses and durations . 67
6.3 Testing components for multiple stresses . 67
6.4 Accelerated testing of assemblies . 68
6.5 Accelerated testing of systems . 68
6.6 Analysis of test results . 68
7 Limitations of accelerated testing methodology . 68
Annex A (informative) Highly accelerated limit test (HALT) . 70
A.1 HALT procedure . 70
A.2 HALT step-by-step procedure. 70
A.3 Example 1 – HALT test results for a DC/DC converter . 72
A.4 Example 2 – HALT test results for a medical product item . 73
A.5 HALT test results for a Hi-Fi equipment . 74
Annex B (informative) Accelerated reliability compliance and growth test design . 75
B.1 Use environment and test acceleration . 75
B.2 Determination of stresses and stress duration . 75
B.3 Overall acceleration of a reliability test . 77
B.4 Example of reliability compliance test design assuming constant failure rate
or failure intensity . 79
B.4.1 General . 79
B.4.2 Thermal cycling . 81
B.4.3 Thermal exposure, thermal dwell . 82
B.4.4 Humidity . 83
B.4.5 Vibration test . 84
B.4.6 Accelerations summary and overall acceleration . 85
B.5 Example of accelerated reliability growth test data analysis .
B.5 Example of reliability compliance test design assuming non-constant failure
rate or failure intensity (wear-out). 96
Annex C (informative) Comparison between HALT and conventional accelerated
testing .
Annex C (informative) Estimating the activation energy, Ea . 98
Annex D (informative) Calibrated accelerated life testing (CALT) . 100
D.1 Purpose of test . 100
D.2 Test execution . 100
Annex E (informative) Example of how to estimate empirical factors . 102
Annex F (informative) Determination of acceleration factors by testing to failure . 109
F.1 Failure modes and acceleration factors . 109
F.2 Example of determination of acceleration factor . 109
Annex G (informative) Median rank tables 95 % rank. 113
Bibliography . 115
List of comments . 118

Figure 1 – Probability density functions (PDF) for cumulative damage, degradation,
and test types . 14
Figure 2 – Relationship of PDFs of the product item strength versus load in use . 19
Figure 3 – How uncertainty of load and strength affects the test policy .
Figure 3 – How HALT tests detect the design margin . 21

– 4 – IEC 62506:2023 CMV © IEC 2023
Figure 4 – PDFs of operating and destruct limits as a function of applied stress . 22
Figure 5 – Line plot for Arrhenius reaction model . 38
Figure 6 – Plot for determination of the activation energy . 39
Figure 7 – Multiplier of the test stress duration for demonstration of required reliability
for compliance or reliability growth testing .
Figure 7 – Bathtub curve . 53
Figure 8 – Multiplier of the duration of the load application for the desired reliability .
Figure 8 – Test planning with a Weibull distribution . 56
Figure 9 – Example of a test based on the Weibull distribution. 57
Figure 10 – Life time and "tail" of the failure rate or failure intensity . 58
Figure 11 – Reliability as a function of life time ratio L and number of test items . 59
v
Figure 12 – Nomogram for test planning .
...

IEC 62506 ®
Edition 2.0 2023-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Methods for product accelerated testing
Méthodes d'essais accélérés de produits
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 IEC or IEC's member National Committee in the country of the requester. If you have any questions about IEC
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About the IEC
The International Electrotechnical Commission (IEC) is the leading global organization that prepares and publishes
International Standards for all electrical, electronic and related technologies.
About IEC publications
The technical content of IEC publications is kept under constant review by the IEC. Please make sure that you have the
latest edition, a corrigendum or an amendment might have been published.
IEC publications search - webstore.iec.ch/advsearchform IEC Products & Services Portal - products.iec.ch
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a month by email.
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IEC 62506 ®
Edition 2.0 2023-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Methods for product accelerated testing
Méthodes d'essais accélérés de produits
INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
INTERNATIONALE
ICS 03.120.01, 21.020 ISBN 978-2-8322-7727-0
– 2 – IEC 62506:2023 © IEC 2023
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions, symbols and abbreviated terms . 9
3.1 Terms and definitions . 9
3.2 Symbols and abbreviated terms . 11
4 General description of the accelerated test methods . 12
4.1 Cumulative damage model . 12
4.2 Classification, methods and types of test acceleration . 14
4.2.1 General . 14
4.2.2 Type A: qualitative accelerated tests . 15
4.2.3 Type B: quantitative accelerated tests . 15
4.2.4 Type C: quantitative time and event compressed tests . 16
5 Accelerated test models . 17
5.1 Type A, qualitative accelerated tests . 17
5.1.1 Highly accelerated limit tests (HALT) . 17
5.1.2 Highly accelerated stress test (HAST) . 21
5.1.3 Highly accelerated stress screening or audit (HASS or HASA) . 22
5.1.4 Engineering aspects of HALT and HASS . 23
5.2 Types B and C – Quantitative accelerated test methods. 23
5.2.1 Purpose of quantitative accelerated testing . 23
5.2.2 Physical basis for the quantitative accelerated Type B test methods . 23
5.2.3 Type C tests, time (C ) and event (C ) compression . 25
1 2
5.3 Failure mechanisms and test design . 27
5.4 Determination of stress levels, profiles and combinations in use and test –
Stress modelling . 27
5.4.1 General . 27
5.4.2 Step-by-step procedure . 28
5.5 Multiple stress acceleration methodology – Type B tests . 28
5.6 Single and multiple stress acceleration for Type B tests . 31
5.6.1 Single stress acceleration methodology . 31
5.6.2 Stress models with stress varying as a function of time – Type B tests . 38
5.6.3 Stress models that depend on repetition of stress applications – Fatigue
models. 40
5.6.4 Other acceleration models . 41
5.7 Acceleration of quantitative reliability tests. 42
5.7.1 Reliability requirements, goals, and use profile . 42
5.7.2 Accelerated testing for reliability demonstration or life tests . 44
5.7.3 Testing of components for a reliability measure . 55
5.7.4 Reliability measures for components and systems . 56
5.8 Accelerated reliability compliance or evaluation tests . 57
5.9 Accelerated reliability growth testing . 58
5.10 Guidelines for accelerated testing . 59
5.10.1 Accelerated testing for multiple stresses and the known use profile . 59
5.10.2 Level of accelerated stresses . 59
5.10.3 Accelerated reliability and verification tests . 59

6 Accelerated testing strategy in product development . 60
6.1 Accelerated testing sampling plan . 60
6.2 General discussion about test stresses and durations . 60
6.3 Testing components for multiple stresses. 61
6.4 Accelerated testing of assemblies . 61
6.5 Accelerated testing of systems . 61
6.6 Analysis of test results . 62
7 Limitations of accelerated testing methodology . 62
Annex A (informative) Highly accelerated limit test (HALT) . 63
A.1 HALT procedure . 63
A.2 HALT step-by-step procedure . 63
A.3 Example 1 – HALT test results for a DC/DC converter. 65
A.4 Example 2 – HALT test results for a medical item . 65
A.5 HALT test results for a Hi-Fi equipment . 67
Annex B (informative) Accelerated reliability compliance and growth test design . 68
B.1 Use environment and test acceleration . 68
B.2 Determination of stresses and stress duration . 68
B.3 Overall acceleration of a reliability test . 69
B.4 Example of reliability compliance test design assuming constant failure rate
or failure intensity . 70
B.4.1 General . 70
B.4.2 Thermal cycling . 71
B.4.3 Thermal exposure, thermal dwell . 72
B.4.4 Humidity . 72
B.4.5 Vibration test . 73
B.4.6 Accelerations summary and overall acceleration . 73
B.5 Example of reliability compliance test design assuming non-constant failure

rate or failure intensity (wear-out) . 75
Annex C (informative) Estimating the activation energy, E . 76
a
Annex D (informative) Calibrated accelerated life testing (CALT) . 78
D.1 Purpose of test . 78
D.2 Test execution . 78
Annex E (informative) Example of how to estimate empirical factors . 80
Annex F (informative) Determination of acceleration factors by testing to failure . 83
F.1 Failure modes and acceleration factors . 83
F.2 Example of determination of accelerat
...