IEC/ISO 31010:2009

IEC/ISO 31010
Edition 1.0 2009-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Risk management – Risk assessment techniques

Gestion des risques – Techniques d'évaluation des risques

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IEC/ISO 31010
Edition 1.0 2009-11
INTERNATIONAL
STANDARD
NORME
INTERNATIONALE
colour
inside
Risk management – Risk assessment techniques

Gestion des risques – Techniques d'évaluation des risques

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
COMMISSION
ELECTROTECHNIQUE
PRICE CODE
INTERNATIONALE
XD
CODE PRIX
ICS 03.100.01 ISBN 978-2-88910-788-9

– 2 – 31010 © IEC:2009
CONTENTS
FOREWORD.4

INTRODUCTION.6

1 Scope.7

2 Normative references .7

3 Terms and definitions .7

4 Risk assessment concepts .7

4.1 Purpose and benefits .7

4.2 Risk assessment and the risk management framework .8
4.3 Risk assessment and the risk management process .8
4.3.1 General .8
4.3.2 Communication and consultation .9
4.3.3 Establishing the context.9
4.3.4 Risk assessment .10
4.3.5 Risk treatment .10
4.3.6 Monitoring and review .11
5 Risk assessment process .11
5.1 Overview .11
5.2 Risk identification .12
5.3 Risk analysis .12
5.3.1 General .12
5.3.2 Controls Assessment.13
5.3.3 Consequence analysis.14
5.3.4 Likelihood analysis and probability estimation .14
5.3.5 Preliminary Analysis .15
5.3.6 Uncertainties and sensitivities .15
5.4 Risk evaluation.15
5.5 Documentation .16
5.6 Monitoring and Reviewing Risk Assessment.17
5.7 Application of risk assessment during life cycle phases .17
6 Selection of risk assessment techniques .17
6.1 General .17
6.2 Selection of techniques .17

6.2.1 Availability of Resources .18
6.2.2 The Nature and Degree of Uncertainty.18
6.2.3 Complexity .19
6.3 Application of risk assessment during life cycle phases .19
6.4 Types of risk assessment techniques .19
Annex A (informative) Comparison of risk assessment techniques .21
Annex B (informative) Risk assessment techniques .27
Bibliography.90

Figure 1 – Contribution of risk assessment to the risk management process .11
Figure B.1 – Dose-response curve.37
Figure B.2 – Example of an FTA from IEC 60-300-3-9.49
Figure B.3 – Example of an Event tree.52

31010 © IEC:2009 – 3 –
Figure B.4 – Example of Cause-consequence analysis .55

Figure B.5 – Example of Ishikawa or Fishbone diagram .57

Figure B.6 – Example of tree formulation of cause-and-effect analysis.58

Figure B.7 – Example of Human reliability assessment .64

Figure B.8 – Example Bow tie diagram for unwanted consequences .66

Figure B.9 – Example of System Markov diagram .70

Figure B.10 – Example of State transition diagram.71

Figure B.11 – Sample Bayes’ net .77

Figure B.12 – The ALARP concept.79
Figure B.13 – Part example of a consequence criteria table.84
Figure B.14 – Part example of a risk ranking matrix .84
Figure B.15 – Part example of a probability criteria matrix .85

Table A.1 – Applicability of tools used for risk assessment .22
Table A.2 – Attributes of a selection of risk assessment tools .23
Table B.1 – Example of possible HAZOP guidewords .34
Table B.2 – Markov matrix .70
Table B.3 – Final Markov matrix.72
Table B.4 – Example of Monte Carlo Simulation .74
Table B.5 – Bayes’ table data .77
Table B.6 – Prior probabilities for nodes A and B .77
Table B.7 – Conditional probabilities for node C with node A and node B defined .77
Table B.8 – Conditional probabilities for node D with node A and node C defined .78
Table B.9 – Posterior probability for nodes A and B with node D and Node C defined .78
Table B.10 – Posterior probability for node A with node D and node C defined .78

– 4 – 31010 © IEC:2009
INTERNATIONAL ELECTROTECHNICAL COMMISSION

____________
RISK MANAGEMENT –
RISK ASSESSMENT TECHNIQUES
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,
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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-
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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. Whi
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