Analysis techniques for system reliability - Procedure for failure mode and effects analysis (FMEA)

This International Standard describes Failure Mode and Effects Analysis (FMEA) and Failure Mode, Effects and Criticality Analysis (FMECA), and gives guidance as to how they may be applied to achieve various objectives by: providing the procedural steps necessary to perform analysis; identifying appropriate terms; defining basic principles; providing examples of the necessary worksheets or other tabular forms.

Analysetechniken für die Funktionsfähigkeit von Systemen - Verfahren für die Fehlzustandsart- und -auswirkungsanalyse (FMEA)

Techniques d'analyse de la fiabilité du système - Procédure d'analyse des modes de défaillance et de leurs effets (AMDE)

La présente Norme Internationale décrit l'analyse des modes de défaillance et de leurs effets (AMDE) et l'analyse des modes de défaillance, de leurs effets et de leur criticité (AMDEC), et apporte des conseils sur l'application de ces méthodes selon les divers objectifs recherchés, de la façon suivante: en fournissant la procédure à suivre pour réaliser une analyse, en spécifiant les termes pertinents, les hypothèses, les mesures de criticité, les modes de défaillance, en déterminant les principes de base, en fournissant des exemples-types de documents et tableaux.

Analizne tehnike za sistemsko zanesljivost – Postopek za analizo vrste okvar in njihovih učinkov (FMEA) (IEC 60812-2006)

General Information

Status
Withdrawn
Publication Date
16-May-2006
Technical Committee
Drafting Committee
Parallel Committee
Current Stage
6060 - Document made available
Completion Date
17-May-2006

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SIST EN 60812:2007
01-januar-2007
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Analysis techniques for system reliability - Procedure for failure mode and effects

analysis (FMEA)
Analysetechniken für die Funktionsfähigkeit von Systemen - Verfahren für die
Fehlzustandsart- und -auswirkungsanalyse (FMEA)

Techniques d'analyse de la fiabilité du système - Procédure d'analyse des modes de

défaillance et de leurs effets (AMDE)
Ta slovenski standard je istoveten z: EN 60812:2006
ICS:
21.020 =QDþLOQRVWLLQQDþUWRYDQMH Characteristics and design of
VWURMHYDSDUDWRYRSUHPH machines, apparatus,
equipment
SIST EN 60812:2007 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN 60812:2007
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SIST EN 60812:2007
EUROPEAN STANDARD
EN 60812
NORME EUROPÉENNE
May 2006
EUROPÄISCHE NORM
ICS 03.120.01; 03.120.30; 21.020 Supersedes HD 485 S1:1987
English version
Analysis techniques for system reliability –
Procedure for failure mode and effects analysis (FMEA)
(IEC 60812:2006)
Techniques d'analyse Analysetechniken für
de la fiabilité du système – die Funktionsfähigkeit von Systemen –
Procédure d'analyse des modes Verfahren für die Fehlzustandsart-
de défaillance et de leurs effets (AMDE) und -auswirkungsanalyse (FMEA)
(CEI 60812:2006) (IEC 60812:2006)

This European Standard was approved by CENELEC on 2006-03-01. 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 Central Secretariat 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 Central Secretariat has the same status as the official versions.

CENELEC members are the national electrotechnical committees of Austria, Belgium, Cyprus, the Czech

Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia,

Lithuania, Luxembourg, Malta, the Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain,

Sweden, Switzerland and the United Kingdom.
CENELEC
European Committee for Electrotechnical Standardization
Comité Européen de Normalisation Electrotechnique
Europäisches Komitee für Elektrotechnische Normung
Central Secretariat: rue de Stassart 35, B - 1050 Brussels

© 2006 CENELEC - All rights of exploitation in any form and by any means reserved worldwide for CENELEC members.

Ref. No. EN 60812:2006 E
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SIST EN 60812:2007
EN 60812:2006 - 2 -
Foreword

The text of document 56/1072/FDIS, future edition 2 of IEC 60812, prepared by IEC TC 56,

Dependability, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as

EN 60812 on 2006-03-01.
This European Standard supersedes HD 485 S1:1987.
The main changes from HD 485 S1:1987 are as follows:
– introduction of the failure modes effects and criticality concepts;
– inclusion of the methods used widely in the automotive industry;
– added references and relationships to other failure modes analysis methods;
– added examples;
– guidance on advantages and disadvantages of different FMEA methods.
The following dates were fixed:
– latest date by which the EN has to be implemented
at national level by publication of an identical
(dop) 2006-12-01
national standard or by endorsement
– latest date by which the national standards conflicting
(dow) 2009-03-01
with the EN have to be withdrawn
Annex ZA has been added by CENELEC.
__________
Endorsement notice

The text of the International Standard IEC 60812:2006 was approved by CENELEC as a European

Standard without any modification.

In the official version, for Bibliography, the following notes have to be added for the standards indicated:

IEC 60300-1 NOTE Harmonized as EN 60300-1:2003 (not modified).
IEC 60300-2 NOTE Harmonized as EN 60300-2:2004 (not modified).
IEC 61160 NOTE Harmonized as EN 61160:2005 (not modified).
ISO 9000 NOTE Harmonized as EN ISO 9000:2000 (not modified).
__________
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SIST EN 60812:2007
- 3 - EN 60812:2006
Annex ZA
(normative)
Normative references to international publications
with their corresponding European publications

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.

NOTE When an international publication has been modified by common modifications, indicated by (mod), the relevant EN/HD

applies.
Publication Year Title EN/HD Year
IEC 60300-3-1 2003 Dependability management EN 60300-3-1 2004
Part 3-1: Application guide - Analysis
techniques for dependability - Guide on
methodology
1) 2)
IEC 61025 Fault tree analysis (FTA) HD 617 S1
- 1992
1) 2)
IEC 61078 Analysis techniques for dependability - EN 61078
- 2006
Reliability block diagram and Boolean
methods
Undated reference.
Valid edition at date of issue.
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SIST EN 60812:2007
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SIST EN 60812:2007
INTERNATIONAL IEC
STANDARD 60812
Second edition
2006-01
Analysis techniques for system reliability –
Procedure for failure mode
and effects analysis (FMEA)
© IEC 2006 Copyright - all rights reserved

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 the publisher.

International Electrotechnical Commission, 3, rue de Varembé, PO Box 131, CH-1211 Geneva 20, Switzerland

Telephone: +41 22 919 02 11 Telefax: +41 22 919 03 00 E-mail: inmail@iec.ch Web: www.iec.ch

PRICE CODE
Commission Electrotechnique Internationale
International Electrotechnical Commission
МеждународнаяЭлектротехническаяКомиссия
For price, see current catalogue
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SIST EN 60812:2007
60812  IEC:2006 – 3 –
CONTENTS

FOREWORD...........................................................................................................................7

1 Scope.............................................................................................................................11

2 Normative references .....................................................................................................11

3 Terms and definitions .....................................................................................................11

4 Overview ........................................................................................................................15

4.1 Introduction ...........................................................................................................15

4.2 Purpose and objectives of the analysis..................................................................17

5 Failure modes and effects analysis.................................................................................19

5.1 General considerations..........................................................................................19

5.2 Preliminary tasks...................................................................................................21

5.3 Failure mode, effects, and criticality analysis (FMECA) .........................................41

5.4 Report of analysis .................................................................................................55

6 Other considerations ......................................................................................................59

6.1 Common-cause failures.........................................................................................59

6.2 Human factors.......................................................................................................59

6.3 Software errors .....................................................................................................61

6.4 FMEA regarding consequences of system failure ..................................................61

7 Applications....................................................................................................................61

7.1 Use of FMEA/FMECA ............................................................................................61

7.2 Benefits of FMEA ..................................................................................................65

7.3 Limitations and deficiencies of FMEA ....................................................................65

7.4 Relationships with other methods ..........................................................................67

Annex A (informative) Summary of procedures for FMEA and FMECA .................................71

Annex B (informative) Examples of analyses........................................................................79

Bibliography..........................................................................................................................93

Figure 1 – Relationship between failure modes and failure effects in a system hierarchy ......25

Figure 2 – Analysis flowchart ................................................................................................39

Figure 3 – Criticality matrix ...................................................................................................47

Figure A.1 – Example of the format of an FMEA worksheet...................................................77

Figure B.1 – FMEA for a part of automotive electronics with RPN calculation........................81

Figure B.2 – Diagram of subsystems of a motor generator set ..............................................83

Figure B.3 – Diagram of enclosure heating, ventilation and cooling systems .........................85

Figure B.4 – FMEA for sub-system 20...................................................................................87

Figure B.5 − Part of a process FMECA for machined aluminium casting................................91

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SIST EN 60812:2007
60812  IEC:2006 – 5 –

Table 1 – Example of a set of general failure modes.............................................................29

Table 2 – Illustrative example of a severity classification for end effects ...............................35

Table 3 – Risk/criticality matrix .............................................................................................49

Table 4 – Failure mode severity............................................................................................51

Table 5 – Failure mode occurrence related to frequency and probability of occurrence .........51

Table 6 – Failure mode detection evaluation criteria .............................................................53

Table 7 – Example of a set of failure effects (for a motor vehicle starter) ..............................57

Table 8 – Example of a failure effects probability ..................................................................57

Table B.1 – Definition and classification of the severity of the effects of failures on the

complete M-G system ...........................................................................................................83

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SIST EN 60812:2007
60812  IEC:2006 – 7 –
INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
ANALYSIS TECHNIQUES FOR SYSTEM RELIABILITY –
PROCEDURE FOR FAILURE MODE
AND EFFECTS ANALYSIS (FMEA)
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 provides no marking procedure to indicate its approval and cannot be rendered responsible for any

equipment declared to be in conformity with an IEC Publication.

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.

International Standard IEC 60812 has been prepared by IEC technical committee 56:

Dependability.

This second edition cancels and replaces the first edition published in 1985 and constitutes a

technical revision.
The main changes from the previous edition are as follows:
– introduction of the failure modes effects and criticality concepts;
– inclusion of the methods used widely in the automotive industry;
– added references and relationships to other failure modes analysis methods;
– added examples;
– provided guidance of advantages and disadvantages of different FMEA methods.
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SIST EN 60812:2007
60812  IEC:2006 – 9 –
The text of this standard is based on the following documents:
FDIS Report on voting
56/1072/FDIS 56/1091/RVD

Full information on the voting for the approval of this standard can be found in the report on

voting indicated in the above table.

This publication has been drafted in accordance with the ISO/IEC Directives, Part 2.

The committee has decided that the contents of this publication will remain unchanged until

the maintenance result date indicated on the IEC web site under "http://webstore.iec.ch" in

the data related to the specific publication. At this date, the publication will be

• reconfirmed;
• withdrawn;
• replaced by a revised edition, or
• amended.
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SIST EN 60812:2007
60812  IEC:2006 – 11 –
ANALYSIS TECHNIQUES FOR SYSTEM RELIABILITY –
PROCEDURE FOR FAILURE MODE
AND EFFECTS ANALYSIS (FMEA)
1 Scope

This International Standard describes Failure Mode and Effects Analysis (FMEA) and Failure

Mode, Effects and Criticality Analysis (FMECA), and gives guidance as to how they may be

applied to achieve various objectives by
− providing the procedural steps necessary to perform an analysis;

− identifying appropriate terms, assumptions, criticality measures, failure modes;

− defining basic principles;
− providing examples of the necessary worksheets or other tabular forms.

All the general qualitative considerations presented for FMEA will apply to FMECA, since the

latter is an extension of the other.
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.

IEC 60300-3-1:2003, Dependability management – Part 3-1: Application guide – Analysis

techniques for dependability – Guide on methodology
IEC 61025, Fault tree analysis (FTA)

IEC 61078, Analysis techniques for dependability – Reliability block diagram method

3 Terms and definitions
For the purposes of this document, the following definitions apply.
3.1
item

any part, component, device, subsystem, functional unit, equipment or system that can be

individually considered

NOTE 1 An item may consist of hardware, software or both, and may also in particular cases include people.

NOTE 2 A number of items, e.g. a population of items or a sample, may itself be considered as an item.

[IEV 191-01-01]
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SIST EN 60812:2007
60812  IEC:2006 – 13 –

A process can also be defined as an item which carries out a predetermined function and for

which a process FMEA or FMECA is carried out. Normally, a hardware FMEA does not

address people and their interactions with hardware/software, while a process FMEA normally

includes actions of people.
3.2
failure
termination of the ability of an item to perform a required function
[IEV 191-04-01]
3.3
fault

state of an item characterized by the inability to perform a required function, excluding the

inability during preventive maintenance or other planned actions, or due to lack of external

resources

NOTE 1 A fault is often the result of a failure of the item itself, but may exist without prior failure.

[IEV 191-05-01]

NOTE 2 In this document “fault” is used interchangeably with the term “failure” for historical reasons.

3.4
failure effect

consequence of a failure mode in terms of the operation, function or status of the item

3.5
failure mode
manner in which an item fails
3.6
failure criticality

combination of the severity of an effect and the frequency of its occurrence or other attributes

of a failure as a measure of the need for addressing and mitigation
3.7
system
set of interrelated or interacting elements
NOTE 1 In the context of dependability, a system will have
a) defined purposes expressed in terms of required functions;
b) stated conditions of operation use (see 191-01-12);
c) a defined boundary.
NOTE 2 The structure of a system is hierarchical.
[ISO 9000:2000]
3.8
failure severity

significance or grading of the failure mode’s effect on item operation, on the item surrounding,

or on the item operator; failure mode effect severity as related to the defined boundaries of

the analysed system
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SIST EN 60812:2007
60812  IEC:2006 – 15 –
4 Overview
4.1 Introduction

Failure Modes and Effect Analysis (FMEA) is a systematic procedure for the analysis of a

system to identify the potential failure modes, their causes and effects on system performance

(performance of the immediate assembly and the entire system or a process). Here, the term

system is used as a representation of hardware, software (with their interaction) or a process.

The analysis is successfully performed preferably early in the development cycle so that

removal or mitigation of the failure mode is most cost effective. This analysis can be initiated

as soon as the system is defined enough to be presented as a functional block diagram where

performance of its elements can be defined.

FMEA timing is essential; if done early enough in the development cycle, then incorporating

the design changes to overcome deficiencies identified by the FMEA may be cost effective. It

is therefore important that the FMEA task and its deliverables be incorporated into the

development plan and schedule. Thus, FMEA is an iterative process that takes place

coincidentally with design process.

FMEA is applicable at various levels of system decomposition from the highest level of block

diagram down to the functions of discrete components or software commands. The FMEA is

also an iterative process that is updated as the design develops. Design changes will require

that relevant parts of the FMEA be reviewed and updated.

A thorough FMEA is a result of a team composed of individuals qualified to recognize and

assess the magnitude and consequences of various types of potential inadequacies in the

product design that might lead to failures. Advantage of the team work is that it stimulates

thought process, and ensures necessary expertise.

FMEA is considered to be a method to identify the severity of potential failure modes and to

provide an input to mitigating measures to reduce risk. In some applications however, FMEA

also includes an estimation of the probability of occurrence of the failure modes. This

enhances the analysis by providing a measure of the failure mode’s likelihood.

Application of FMEA is preceded by a hierarchical decomposition of the system (hardware

with software, or a process) into its more basic elements. It is useful to employ simple block

diagrams to illustrate this decomposition (IEC 61078). The analysis then starts with lowest

level elements. A failure mode effect at a lower level may then become a failure cause of a

failure mode of an item in the next higher level. The analysis proceeds in a bottom-up fashion

until the end effect on the system is identified. Figure 1 illustrates this relationship.

FMECA (Failure Modes, Effects and Criticality Analysis) is an extension to the FMEA to

include a means of ranking the severity of the failure modes to allow prioritization of

countermeasures. This is done by combining the severity measure and frequency of occur-

rence to produce a metric called criticality.

The principles of an FMEA may be applied outside of engineering design. FMEA procedure

can be applied to a manufacturing or any other work process such as in hospitals, medical

laboratories, school systems, or others. When FMEA is applied to a manufacturing process,

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SIST EN 60812:2007
60812  IEC:2006 – 17 –

this procedure is known in industry as the Process FMEA, or PFMEA. For an FMEA to be

effective, adequate resources for a team work have to be committed. A thorough

understanding of the system under analysis may not be essential for a preliminary FMEA.

With development of design, a detailed failure mode analysis requires thorough knowledge of

the design performance and its specifications. Complex engineering designs usually require

the involvement of multiple areas of design expertise (e.g. mechanical engineering, electrical

engineering, systems engineering, software engineering, maintenance support, etc).

FMEA generally deals with individual failure modes and the effect of these failure modes on

the system. Each failure mode is treated as independent. The procedure is therefore

unsuitable for consideration of dependent failures or failures resulting from a sequence of

events. To analyse these situations other methods and techniques, such as Markov analysis

(see IEC 61165) or fault tree analysis (see IEC 61025), may be required.

In determining the impact of a failure, one must consider higher level induced – resultant

failures and possibly the same level of induced failures. The analysis should indicate,

wherever possible the combination of failure modes or their sequence that was a cause of a

higher level effect. In that case additional modelling is required to estimate the magnitude or

probability of occurrence of such an effect.

FMEA is a flexible tool that can be tailored to meet specific industry or product needs.

Specialized worksheets requiring specific entries may be adapted for certain applications. If

severity levels of failure modes are defined, they may be defined differently for different

systems or different system levels.
4.2 Purpose and objectives of the analysis

The reasons for undertaking Failure Mode Effects Analysis (FMEA) or Failure Mode Effects

and Criticality Analysis (FMECA) may include the following:

a) to identify those failures which have unwanted effects on system operation, e.g. preclude

or significantly degrade operation or affect the safety of the user;
b) to satisfy contractual requirements of a customer, as applicable;

c) to allow improvements of the system’s reliability or safety (e.g. by design modifications or

quality assurance actions);

d) to allow improvement of the system’s maintainability (by highlighting areas of risk or

nonconformity for maintainability).

In view of the above reasons for undertaking a FMEA effort, the objectives of an FMEA (or

FMECA) may include the following:

a) a comprehensive identification and evaluation of all the unwanted effects within the

defined boundaries of the system being analysed, and the sequences of events brought

about by each identified item failure mode, from whatever cause, at various levels of the

system’s functional hierarchy;

b) the determination of the criticality or priority for addressing/mitigation (see Clause 6) of

each failure mode with respect to the system’s correct function or performance and the

impact on the process concerned;
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SIST EN 60812:2007
60812  IEC:2006 – 19 –

c) a classification of identified failure modes according to relevant characteristics, including

their ease of detection, capability to be diagnosed, testability, compensating and operating

provisions (repair, maintenance, logistics, etc.);

d) identification of system functional failures and estimation of measures of the severity and

probability of failure;
e) development of design improvement plan for mitigation of failure modes;

f) support the development of an effective maintenance plan to mitigate or reduce likelihood

of failure (see IEC 60300-3-11).

NOTE When criticality or probability of occurrence is addressed, the comments regard FMECA methodology.

5 Failure modes and effects analysis
5.1 General considerations

Traditionally there have been wide variations in the manner in which FMEA is conducted and

presented. The analysis is usually done by identifying the failure modes, their respective

causes and immediate and final effects. The analytical results can be presented on a

worksheet that contains a core of essential information for entire system and details

developed for that specific system. It shows the ways the system could potentially fail, the

components and their failure modes that would be the cause of system failure, and the

cause(s) of occurrence of each individual failure mode.

The FMEA effort applied to the complex products might be very extensive. This effort may be

sometimes reduced by having in mind that design of some subassemblies or their parts may

not be entirely new and by identifying parts of the product design that are a repetition or a

modification of a previous product design. The newly constructed FMEA should use

information on those existing subassemblies to the highest possible extent. It must also point

to the need for eventual test or full analysis of the new features and items. Once a detailed

FMEA is created for one design, it can be updated and improved for the succeeding

generations of that design, which constitutes a significantly less effort than the entirely new

analysis.

When using an existing FMEA from a previous product version, it is essential to make sure

that the repeated design is indeed used in the same manner and under the same stresses as

the previous design. The new operational or environmental stresses may require review of the

previously completed FMEA. Different environmental and operational stresses may require an

entirely new FMEA to be created in view of the new operational conditions.
The FMEA procedure consists of the following four main stages:
...

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